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BACKGROUND OF THE INVENTION
The present invention generally relates to fluid cleaning compositions containing water and one or more surfactants, soaps and/or detergents. More particularly, it relates to a new and improved thickening agent containing an amide useful for thickening liquid cleaner compositions.
Illustrative examples of cleaning compositions containing a mixture of at least one surface-active agent whose viscosity characteristics may need to be modified or increased may include cosmetics, such as shampoos, shower gels or creams, as well as, liquid detergents for use in the home, e.g., dishwashing liquids, bathroom and toilet cleaners and gels, and liquid laundry detergents, to name but a few. It may be desired to modify the viscosity of these liquids by increasing the viscosity to provide thicker or thickened liquids.
It is well known that surface-active agents in a dilute mixtures produce low viscosity formulations. Whenever the mixture has a low viscosity, contact with the surface on which it is used is often undesirably short, i.e., the cleaner runs or rolls off the surface. Moreover, since the product flows more easily, it has no time to react with the surface so that the user tends to use too much of the cleaner.
In order to solve this problem, many thickening agents have been added into cleaner compositions. Among them diethanolamides that are prepared with secondary amides. These materials contain high amounts of nitrosamines which is a serious drawback because it is well known that nitrosamines are carcinogenic. Copra diethanolamides have been extensively used for this purpose since they are in a liquid form and can be easily handled at room temperature, despite the fact that they contain nitrosamines. Moreover, copra diethanolamides do not provide high viscosity mixtures except at relatively high amide concentrations.
The use of palm, copra, stearin and olein monoisopropanolamides has also been suggested, because these amides generally do not contain nitrosamines since they are prepared from primary amines. However, these amides are solid at ambient or room temperatures and therefore are difficult to handle.
Furthermore, until recently, in order to obtain a cleaning mixture with a desirably high viscosity, it has been necessary to add a large quantity of mineral salt, such as sodium chloride or magnesium sulfate. For a given quantity of thickening amide, viscosity of the overall formulation increases to a maximum as mineral salts are added and then decreases. With the type of amides used, optimum viscosity can only be achieved with relatively high quantities of mineral salts (NaCl, MgSO 4 ). A major disadvantage associated with adding large amounts of mineral salts to the formulation is that the cleaner product is less stable at low temperature and less soft when used. These drawbacks are even greater when the mineral salt content is higher.
According to this invention, it is easy to prepare mixtures containing at least one surface-active agent, having a desirably high viscosity, having only a minimum quantity of mineral salts. More particularly, superior viscosity modification at lower salt concentrations is provided by using certain room temperature liquid amides as the thickening agent which do not contain nitrosamines.
SUMMARY OF THE INVENTION
A primary object of this invention is to provide a new and improved thickener for cleaner compositions comprising certain fatty acid amides derived from beta-hydroxyalkyl units and terminally-branched fatty acid units having a long hydrocarbon chain containing at least about 15 carbons in length. In accordance with the preferred embodiment, the new and improved amide thickener in accordance with this invention comprises a N-2-hydroxypropyl-isostearyl amide: ##STR1##
It has been observed that in addition to its excellent viscosity, 2-hydroxypropyl-isostearyl amide has softening, lubrifying, emulsifying and foam-intensifying properties. Another advantage of 2-hydroxypropyl-isostearyl amide is that ambient temperature mixtures containing at least one surface-active agent can be formulated because the amide is a liquid and easy to handle at this temperature. It is therefore easy to introduce with surface active agents.
The preferred amide shown in structural formula (1) can be obtained by condensing isostearic acid and amino-1 propanol-2 (also called 2-hydroxypropylamine, monoisopropanolamine or MIPA). At 20° C. the product looks like a clear to slightly cloudy liquid which gets clearer between 30° and 40° C. The density of this amide, measured at 40° C. is equal to about 0.0904 and its viscosity at 40° C. is equal to about 320 mPa.s.
In addition, the invention relates to a thickening agent that can be used in mixtures containing at least one surface-active agent which is made up of at least one fatty acid amide characterized by the fact that it contains the amide given in structural formula (1). The thickening agent contains at least 90 weight % of the amide given in structural formula (1).
The thickening agent in this invention meets the following specifications:
______________________________________Visual at 25° C. Clear to slightly cloudy liquidDensity at 40° C. 0.900-0.908Viscosity at 40° C. 310 to 330 Mpa · sColor at 40° C. (measured ≦3in Gardner units)Acidity (in mg KOH/G) ≦3Free amine content (weight %) ≦1Esteramide content (weight %) ≦5Ph measured in a weight 8 to 9% solution in a water/isopropanol mixture (50/50in volume)Water content ≦0.5______________________________________
This invention also relates to thickened compositions comprising a liquid or pasty mixture containing at least one surface-active agent and an effective quantity of the thickening agent defined above. Other object and advantages provided by the present invention will become apparent from the following Detailed Description of the Preferred Embodiments, taken in conjunction with the Drawings, in which:
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a copy of the Infra-Red Spectrum of the new and improved 2-hydroxypropyl-isostearyl amide thickener compound of the present invention;
FIG. 2 is a graphical illustration showing the thickening ability of the thickener of the present invention, curve (a), compared to prior art compounds palm monoisopropanolamide, curve (b) , and copra monoisopropanolamide, curve (c), shown in terms of viscosity, as measured at 20° C. in a Brookfield RVT Viscosimeter, as a function of NaCl mineral salt content; and
FIG. 3 is a graphical plot showing viscosity, as measured at 20° C. in a Brookfield RVT Viscosimeter, as a function of NaCl mineral salt content for a composition without thickener, curve (a); with 0.5% copra diethanolamide as thickener, curve (b); with 1.0% copra diethanolamide as thickener, curve (c); with 0.5% of 2-hydroxypropyl-isostearylamide as thickener in accordance with this invention, curve (d); and with 1.0% of 2-hydroxypropyl-isostearylamide as thickener in accordance with this invention, curve (e).
DETAILED DESCRIPTION OF THE INVENTION
According to the invention, the thickening agent is compatible with most surface-active agents and soaps. Surface-active agents can be selected from the following group in the case of this invention: anionic, cationic, zwitterionic and amphoteric surfactants and mixtures thereof, alkaline alkylamidosulfosuccinates, sodium, potassium or triethanolamine soaps, betaine and sulfobetaines, amphoteric surface-active agents derived from imidazoline, alkylpolyglycolethers, polyalcohols, polyethyleneglycol, and more particularly, sorbitol or ethoxyl sorbitol fatty esters.
More particularly, suitable anionic surfactants are water-soluble salts of C 8 -C 22 alkyl benzene sulfonates, C 8 -C 22 alkyl sulfates, C 10-18 alkyl polyethoxyether sulfates, C 8-24 paraffin sulfonates, alpha--C 12-24 olefin sulfonates, alpha-sulfonated C 6 -C 20 fatty acids and their esters, C 10 -C 18 alkyl glyceryl ether sulfonates, fatty acid monoglyceride sulfates and sulfonates, especially those prepared from coconut oil, C 8 -C 12 alkylphenol polyethoxyether sulfates, 2-acyloxy--acyloxy--C 9 -C 23 alkane-1-sulfonate, and beta-alkyloxy--C 8 -C 20 alkane sulfonates.
Preferably, the anionic surfactant is selected from alkali metal, alkaline earth metal, ammonium, and alkanolammonium salts of alkyl sulfates, alkyl ethoxy sulfates, alkyl benzene sulfonates and mixtures thereof.
The alkyl sulfate component is preferably a primary alkyl sulfate in which the alkyl group contains about 10-16 carbon atoms, more preferably an average of 12-14 carbon atoms. The alkyl group may be linear or branched in configuration. C 10 -C 16 alcohols, derived from natural fats or Ziegler olefin build-up or OXO synthesis, from suitable sources for the alkyl group. Examples of synthetically derived materials include Dobanol 23 (RTM) sold by Shell Chemicals (UK) Ltd., Ethyl 24 sold by the Ethyl Corporation, a blend of C 13 -C 15 alcohols in the ratio 67% C 13 , 33% C 15 sold under the trade name Lutensol by BASF GmbH and Synperonic (RTM) by ICI Ltd., and Lial 125 sold by Liquichimica Italiana. Examples of naturally occurring materials from which the alcohols can be derived are coconut oil and palm kernal oil and the corresponding fatty acids.
For the purposes of the present invention any alkali metal, alkaline earth metal, ammonium or substituted ammonium cation can be used in association with the alkyl sulfate. In particular, the alkyl sulfate can be associated with a source of magnesium ions either introduced as the oxide or hydroxide to neutralize the acid, or added to the composition as a water soluble salt.
Alkyl benzene sulfonates preferred for use in compositions of the present invention are those in which the alkyl group, which is substantially linear, contains about 10-16 carbon atoms, preferably about 11-13 carbon atoms, a material with an average chain length of 11.8 being most preferred. An alkylbenzene sulfonate content of from about 10% to about 28% by weight of the composition is generally suitable. In a preferred aspect of the invention an alkylbenzene sulfonate content of from 13% to 17% by weight is used.
The alkyl ethoxy sulfate surfactant component preferably comprises a primary alkyl ethoxysulfate derived from the condensation product of a C 10 -C 16 alcohol with an average of up to 6 ethylene oxide groups. The C 10 -C 16 alcohol itself can be obtained from any of the sources previously described for the alkyl sulfate component. It has, however, been found preferable to use alkyl sulfate and alkyl ether sulfate in which the carbon chain length distributions are the same. C 12 -C 13 alkyl ether sulfates are preferred.
Conventional ethoxylation processes result in a distribution of individual ethyoxylates ranging from 1 to about 10 ethoxy groups per mole of alcohol, so that the desired average can be obtained in a variety of ways. Blends can be made of material having different degrees of ethoxylation and/or different ethoxylate distributions arising from the specific ethoxylation techniques employed and subsequent processing steps such as distillation. For example, it has been found that approximately equivalent sudsing to that given by a blend of alkyl sulfate and alkyl triethoxy ether sulfate can be obtained by reducing the level of alkyl sulfate and using an alkyl ether sulfate with an average of approximately two ethoxygroups per mole of alcohol. In preferred compositions in accordance with the present invention the average degree of ethoxylation is from about 0.5 to about 4, more preferably from about 0.8 to about 2.0.
Cationic detergents include those having the formula R-N(R 2 ) 3 (+)X(-) wherein R is an alkyl chain containing from about 8 to about 20 carbon atoms, each R 2 is selected from alkyl and alkanol groups containing from 1 to 4 carbon atoms and benzyl groups, there being normally no more than one benzyl group and two R 2 groups can be joined by either a carbon-carbon ether, or imino linkage to form a ring structure, and X represents a halogen atom, sulfate group, nitrate group or other pseudohalogen group, nitrate group or other pseudohalogen group. Specific examples are coconut alkyl trimethyl ammonium chloride, dodecyldimethyl benzyl bromide and dodecyl methyl morpholino chloride.
Zwitterionic synthetic detergents can be broadly described as derivatives of aliphatic quaternary ammonium, phosphonium, and sulfonium compounts, in which the aliphatic radical may be straight chain or branched, and wherein one of the aliphatic substituents contains from about 8 to 18 carbon atoms and one contains an anionic water solubilizing group, e.g., carboxy, sulfo, sulfato, phosphato, or phosphono. Examples of compounds falling within this definition are 3-(N,N-dimethyl-N-hexadecylammonio) propane-1-sulfonate and 3-(N,N-dimethyl-N-hexadecylammonio)-2-hydroxypropane-1-sulfonate.
Amphoteric synthetic detergents can be broadly described as derivatives of aliphatic secondary and tertiary amines, in which the aliphatic radical may be straight chain or branched and wherein one of the aliphatic substituents contains from about 8 to 18 carbon atoms and one contains an anionic water solubilizing group, e.g., carboxy, sulfo, sulfato, phosphato, or phosphone. Examples of compounds falling within this definition are sodium-3-dodecylaminopropionate and sodium-3-dodecylaminopropane sulfonate.
Other suitable surfactants herein are the long chain tertiary amine oxides of general formula:
R.sub.1 R.sub.2 R.sub.3 N+-O.sup.-
wherein R 1 represents alkyl, alkenyl or monohydroxyalkyl radical of from 8 to 18 carbon atoms optionally containing up to 10 ethylene oxide moieties or a glyceryl moiety, and R 2 and R 3 represents alkyl of from 1 to 3 carbon atoms optionally substituted with a hydroxy group, e.g., methyl, ethyl, propyl, hydroxyl ethyl, or hydroxy propyl radicals. Examples includes dimethyldodecylamine oxide, oleyldi(2-hydroxyethyl)amine oxide, dimethyldecylamine oxide, 3,6,9-trioxaheptadecylamine oxide, 2-dodecoxyethyldimethylamine oxide, 3-dodecoxy-2-hydroxypropyl-di-(3-hydroxypropyl)amine oxide, dimethylhexadecylamine oxide. The amine oxide surfactants are generally referred to as semi-polar although in acidic to neutral media they behave akin to cationic surfactants.
According to the invention, the mixtures contain certain quantities of thickening agents that change depending on the type and the quantity of surface-active agent used and on the use of the mixture. These quantities vary between 0.5 to about 5.0% by weight compared to the total weight of the mixture, preferably between 0.1 and 2.5%, more preferably between 0.5 and 1.5%.
Mixtures thickened as per the invention, containing amides, also contain a mineral salt, a chloride, an alkaline-earth sulfate and more particularly sodium chloride or magnesium sulfate; the quantity of sodium chloride or magnesium sulfate required to obtain a given viscosity with a determinate quantity of amide can be reduced by using the amide from structural formula (1) as an essential constituent of the thickening agent; in practice, the quantity of sodium chloride or magnesium sulfate is therefore chosen so as to optimize viscosity according to the quantity of amide from structural formula (1) present in the mixture.
According to the invention, the mixture contains, for example, between 0.25 and 10 weight % of sodium chloride for a quantity or monoisopropanolamide isostearic acid ranging between 0.1 and 2.5%; preferably, it contains between 0.75 and 1.75 weight % of NaCl for 0.5 to 1% of amide from structural formula (1).
According to the invention, the mixture can be used in a shampoo, a cream, a shower gel, a liquid soap or a liquid detergent for cleaning dishes, WV's, tiles.
Monoisopropanolamide isostearic acid can be prepared by reacting isostearic acid with monoiso-propanolamine, through any known amide preparation process. A process through which a stoichiometric quantity or a slight excess of isopropanolamine is reacted with isostearic acid in the presence of phosphoric acid as a catalyst is preferred. However, depending upon the process used, a product can be obtained with too high a colored value (a coloring in Gardner units, greater than 5) with too high a content of esteramides, obtained as a secondary product, as well as, too high a content of free amines. Such a product when used with the amide from structural formula (1) may be problematic, as an appropriate thickening agent in mixtures.
According to the invention, a product with a coloring of 5 (maximum) in Gardner units, a content of 5 weight % (maximum) of esteramides and a content of 1 weight % (Maximum) of free amines can be obtained through the thickening agent preparation process described hereafter.
According to this process:
(a) isostearic acid is introduced in a reaction vessel through which an inert gas current is passed and heated at a temperature ranging from 40° to 70° C.;
(b) in this reaction vessel, an anti-oxidizing agent is then added and mixed for 0.5 to 2 hours;
(c) monoisopropanolamine is gradually introduced into the reaction vessel and temperature is increased until it reaches 90° to 110° C. This temperature is maintained by regulating monoisopropanolamine introduction flow until 1.00 and 1.10 times the number of acid moles has been introduced in the reaction vessel at step (a);
(d) the temperature is maintained and then phosphoric acid (between 2 and 5 parts in weight for 10,000 parts in weight of acid placed in the reaction vessel in step (a) is slowly introduced into the reaction vessel and heated until temperature reaches 145° to 170° C.;
(e) temperature is maintained until the acid is lower than 5 (mg KOH/g);
(f) when acid index is lower than 5, a second quantity of anti-oxidizing agent is added. A low pressure of 4.0 to 1.9×10 3 Pa is established by maintaining the inert gas atmosphere in order to eliminate excess amine;
(g) then, temperature is reduced to under 75° C. by maintaining the inert gas atmosphere and the mixture is allowed to return to room temperature.
The examples given hereafter are illustrations and in no way limitations and will allow permit those skilled in this art to better understand the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
EXAMPLE 1
Preparation of a 2-Hydroxypropyl-isostearylamide Thickener
The following components are used (quantities are given in grams):
______________________________________Isostearic acid 668Monoisopropanolamine 186Phosphoric acid at 85% 0.242.6-di-tert-butyl-p-cresol 1.92(anti-oxidizing agent)______________________________________
A 1 liter reaction vessel is purged with nitrogen and the entire amount of isostearic acid is introduced. The acid is heated at a temperature ranging between 60° and 70° C. under a nitrogen flow of 0.41/h. Thereafter, half of the anti-oxidizing agent is added and maintained under agitation for one hour.
The monoisopropanolamine (MIPA) (2-hydroxypropylamine) is added in a thin stream. The reaction is exothermic and the temperature of the mixture increases. It is allowed to reach 100° C. so as to liquefy the reaction mixture and maintained at 100° C. by regulating the flow of MIPA.
After introducing MIPA, phosphoric acid is slowly introduced at 100° C. Nitrogen flow is doubled and the mixture is heated to 155°-160° C.
This temperature is maintained during the entire reaction until the acid index (in mg KOH/g) is lower than 5. The evolution of reaction is controlled by sampling it every one and a half hours. Acid index as well as alkalinity index are checked. The alkalinity index expressed in mg KOH/g must always be 10 points above the acid index. If it is not the case, the alkalinity index is adjusted by adding MIPA.
During the reaction, the nitrogen flow is gradually increased so that at the end of the reaction it reaches ten times the initial flow use date at the time the isostearic acid is heated. Therefore, the water formed is more easily drained. When the acid index is under 5 (mg KOH/g), the second half of the anti-oxidizing agent is added.
A pressure of 2.66 c 10 3 Pa is set in the reaction vessel under a nitrogen flow of 4.3 liters/hour in order to eliminate excess MIPA through distillation. Distillation temperature of amine is very important because for higher temperatures, a product with too many esteramides would then be obtained. Low pressure is maintained until the alkalinity index is under 0.1 meq/g.
Finally, the reaction mixture is cooled down to 60° C. under a nitrogen flow of 0.91/h and then allowed to come back to ambient temperature.
With a 93% yield compared to the raw materials used, we thus obtain a thickening agent that satisfies the following specifications:
______________________________________Visual at 25° C. Clear to slightly cloudy liquidColor in Gardner 4.5units (%)Acidity (mg KOH/g) 4.2Free amine content (weight %) 0.8Esteramide content (weight %) 4.1Water content 0.05Crystallization point (°C.) 10pH in a 1% solution in a 10water/isopropanol mixture50/50 in volumeViscosity at 40° C. (Mpa · s) 8.8Density at 40° C. 0.904______________________________________
(%) Measurement is taken by comparing coloring disks in normal Gardner units from 1 to 18.
The infra-red spectrum of the compound thus obtained is given in FIG. 1, wherein wavelengths in cm -1 are given on the x-axis and the transmission percentage on the y-axis. This spectrum confirms the fact that the product obtained is essentially made up of 2-hydroxypropyl-isostearyl amide.
EXAMPLE 2
Shampoo Preparation
A shampoo containing variable quantities of sodium chloride has been prepared. It has the following formulation (in weight %):
______________________________________Surface-active agents with sulfo- 15succinates acids sold on the marketas "EMCOL 1484" by "WITCO"Surface-active agents with sodium 20alkylethersulfates sold on themarket as "NEOPON LOS/NF" by "WITCO"Thickening agent 1Sodium chloride 1 to 10Water (balance) 100______________________________________
The thickening agent used is either the thickening agent of the invention obtained by the following Example 1, or, as a comparison, palm monoisopropanolamide sold as "WITCAMIDE PPA" by the WITCO Corporation and copra monoisopropanolamide sold as "WITCAMIDE CPA" by the WITCO Corporation.
Viscosity of the various formulations obtained was measured at 20° C. with a "Brookfield RVT" viscosimeter. The results of these measurements are given in FIG. 2. The percentage of sodium chloride is given on the x-axis and the viscosity measured at 20° C. in mPa.s, on the y-axis. Curve (a) corresponds to the thickening agent of this invention. Curve (b) shows the results obtained with the WITCAMIDE PPA and curve (c) with WITCAMIDE CPA.
FIG. 2 shows that a maximum viscosity obtained with the thickening agent of the invention is substantially similar to the viscosity achieved with the WITCAMIDE CPA and PPA prior art thickeners. A comparison of FIG. 2 results illustrates that for a given viscosity value, the viscosity was achieved using a smaller quantity of NaCl with the thickening agent of the invention, curve (a).
The cloud point of the above mixture containing WITCAMIDE CPA and WITCAMIDE PPA was measured as well as that for the thickening agent of the invention at a NaCl content of 7% and 8%. The results are given in Table 1 hereunder.
TABLE 1______________________________________Thickening Agent NaCl Content Cloud Point °C.______________________________________WITCAMIDE CPA 7% -4 8% -4WITCAMIDE PPA 7% -2 8% -2Thickening agent 7% -7according to Example 1 8% -7______________________________________
Therefore, the cloud point is clearly lower with the thickening agent from Example 1 rather than with WITCAMIDE PPA and CPA. Moreover, for the mixtures containing WITCAMIDE PPA and CPA, it has been observed that crystals have formed as it ages; with the thickening agent of the invention, this phenomena does not occur.
EXAMPLE 3
Preparation of a Dishwashing Liquid
A detergent dishwashing liquid containing 10% active ingredient was prepared with the following formulation (in weight %):
______________________________________Surface-active agents with p-alkylbenzene 23.8sodium sulfonate sold on the marketas "SULFRAMINE 1230" by "WITCO"Surface-active agents with alkylether 10.2sodium sulfate sold as "NEOPON LOS/NF"by "WITCO"Thickening agent 0.05 and 1Sodium chloride 0.5 to 3City supply water (balance) 100______________________________________
The thickening agent used was either the preferred 2-hydroxypropyl-isostearyl amide of Example 1, copra diethanolamide, or copra monoisopropanolamide sold as WITCAMIDE CPA by WITCO Corporation.
Viscosity at 20° C.±1° C. was measured in mPa.s with the help of the Brookfield RVT viscosimeter.
Immediate foaming power has been measured in foam ml and after 5 minutes with a 0.1% solution of dry matter from city water formulations.
Cloud point in °C. has been determined and the appearance of the detergent obtained at 20° C. has been observed.
The results are set forth in Table II hereafter and in FIG. 3. In FIG. 3, curve (a) corresponds to the viscosities obtained with increasing quantities of NaCl without thickening agents, curve (b) with 0.5% of copra diethanolamide, curve (c) with 1% of copra diethanolamide, curve (d) with 0.5% of the thickening agent from Example 1, and curve (e) with 1% of the thickening agent from Example 1. On these curves, the NaCl content is given on the x-axis and viscosity in mPa.s on the y-axis.
TABLE II______________________________________ Foaming Power at 0.1% in city water FoamViscosity after Cloud Visualat 20° C. Immediate 5 min. Point at(mpa · s) foam (ml) (ml) (°C.) 20° C.______________________________________WithoutThickeningagent:As such 25 370 360 -2 clear+ 1.00% 75 clearNaCl+ 2.00% 840 clearNaCl+ 2.50% 1100 350 340 +14 clearNaCl+ 3.00% 360 clearNaCl0.5% agentfromExample 1:As such 30 330 320 -2 clear+ 0.50% 42 clearNaCl+ 1.00% 210 clearNaCl+ 1.25% 960 400 380 -1 clearNaCl+ 1.50% 1600 clearNaCl+ 1.75% 1600 +11 clearNaCl+ 2.00% 750 +18 cloudyNaCl0.5% copradiethanol-amide:As such 25 310 300 -2 clear+ 1.00% 150 clearNaCl+ 1.50% 980 clearNaCl+ 1.75% 1300 360 350 -1 clearNaCl+ 2.00% 1240NaCl0.5% copramonoisopropanolamide+ 1.25% 380 0NaCl+ 1.50% 510 0NaCl+ 1.75% 1160 +3NaCl+ 2.00% 980 +6NaCl1% agentfromExample 1:As such 30 310 300 -2 clear+ 0.30% 100 clearNaCl+ 0.75% 370 -2 clearNaCl+ 1.00% 2400 360 350 +16 clearNaCl+ 1.25% 2000 turbidNaCl1% copradiethanol-amideAs such 25 310 300 -2 clear+ 1.00% 310 clearNaCl+ 1.50% 1450 clearNaCl+ 1.75% 1750 380 370 -1 clearNaCl+ 2.00% 900NaCl1% copramonoisopropanolamide+ 0.50% 75 +2NaCl+ 0.75% 230 -2NaCl+ 1.00% 940 -2NaCl+ 1.25% 1920 -2NaCl______________________________________
Although the present invention has been described with reference to certain preferred embodiments, modifications or changes may be made therein by those skilled in this art. For example, instead of using 2-hydroxypropyl-isostearyl amide as the thickening agent, 2-hydroxyethyl-isostearylamide or 2- or 3-hydroxybutyl-isostearylamide may also be used. All such obvious modifications may be made herein without departing from the scope and spirit of this invention as defined by the appended claims. | New and improved thickeners for mixtures of one or more surface active agent include beta-hydroxyalkyl-terminally branched fatty acid amides. The new and improved thickeners achieve the same or better viscosity with lower amounts of mineral salts being required to be added. Concomitant benefits such as improved softening, lubricity, emulsifying and foam intensifying properties are also achieved. The thickeners and cleaner compositions containing them may also be prepared so that they do not contain nitrosamines, unlike prior art amide thickeners. A preferred thickener in accordance with the invention is 2-hydroxypropyl-isostearyl amide. A novel method for making the preferred thickener, so that it is substantially free of undesirable impurities is also provided. | 2 |
RELATED APPLICATIONS
This application is a divisional of U.S. application Ser. No. 11/110,288 filed Apr. 20, 2005, now U.S. Pat. No. 7,306,030, which is hereby incorporated by reference as though fully set forth herein.
FIELD OF THE INVENTION
This invention relates to flow-circuiting in fluid devices such as heat exchangers.
BACKGROUND OF THE INVENTION
Heat exchangers are commonly used to remove heat from fluids. In the context of the automotive field, for example, it is well-known to use heat exchangers as oil coolers, to transfer heat from engine oil or transmission fluid to engine coolant.
One known type of oil cooler is constructed from a stack of thin-gauge metal plates. The plates are formed such that, in the stack, interstices are formed, the plates and interstices being disposed in alternating relation. The interstices define a plurality of oil passages and a plurality of coolant passages. The oil passages and the coolant passages are disposed in the stack in alternating relation. Thus, each plate separates a respective oil passage from a respective coolant passage, thereby to conduct heat between any contents of the oil passage and any contents of the coolant passage when a temperature differential exists therebetween. The oil passages are coupled to one another in parallel to provide an oil flow path, and the coolant passages are coupled to one another in parallel to provide a coolant flow path. Thus, when a flow of relatively hot oil is delivered to the oil flow path and a flow of relatively cold coolant is delivered to the coolant flow path, a flow of relatively cool oil and a flow of relatively warm coolant results.
As is well known, the heat transfer efficiencies of such structures is a function of the temperature differential between the fluid inlet and outlet, and the relative direction of flow of the fluids passing through the structures.
Normally, it is necessary to manufacture a variety of heat exchangers of varied dimensions to provide heat transfer performance suitable for a particular application in which it is to be employed. However, this necessitates relatively short production runs, which has an associated cost. As well, flexibility for a given application demands that a variety of heat exchangers be on hand, which has an associated inventory cost. Modern manufacturing is very cost-sensitive, and as such, these costs are disadvantageous.
In United States Patent Application Publication No. US 2002/0129926 A1, (Yamaguchi), published Sep. 19, 2002, it is taught to divide the plurality of oil passages into three groups; connect the oil passages of each group in parallel to form a respective oil flow subpath; and connect the oil flow subpaths in series. This provides a heat exchanger wherein the oil path is three times the length and one third the width than that of a heat exchanger of otherwise identical structure wherein all of the oil passages are connected in parallel, and which therefor has heat exchange characteristics differing therefrom. In this reference, which employs a plurality of plates including apertures for forming manifolds for oil and coolant, such separation is attained by omitting the openings in selected plates. This structure arguably overcomes in part the problem of short production runs, since a variety of heat exchangers can be provided simply by altering the number and position of the plates in which openings are omitted. However, this structure does not overcome the problem of inventory cost associated with flexibility.
SUMMARY OF THE INVENTION
In the present invention, an insert is provided. The insert can be snap-fit into place anywhere desired in a fluid device manifold to perform a flow baffling function. This permits a variety of heat exchangers of varying performance characteristics to be readily constructed from a single inventory of basic heat exchange elements, thereby reducing the costs of flexibility and inventory associated with devices of the prior art.
According to one aspect of the invention there is provided an insert for use with a fluid device having a flow distribution passage defined by a peripheral wall formed with opposed recesses therein. The insert comprises a cradle dimensioned to be slidably located in the flow distribution passage to block flow through the flow distribution passage. The cradle has opposed, resilient, outwardly disposed fingers adapted to engage the opposed recesses and retain the insert at an operative position in the flow distribution passage to perform a flow baffling function in use.
According to another aspect of the invention, there is provided a heat exchanger for use with a heat exchange fluid. The heat exchanger comprises a heat exchange element including: a pair of manifolds; and a plurality of heat exchange flow passages extending between the manifolds for the passage of heat exchange fluid through the heat exchange element. One of the manifolds has a flow distribution passage defined by a peripheral wall formed with opposed recesses therein. An insert includes a cradle that is dimensioned to be slidably located in the flow distribution passage in an operative position to block flow through the flow distribution passage. The cradle has opposed, resilient, outwardly disposed fingers engaged in the opposed recesses to retain the insert in the operative position.
Advantages, features and characteristics of the present invention, as well as methods of operation and functions of the related elements of the structure, and the combination of parts and economies of manufacture, will become apparent upon consideration of the following detailed description with reference to the accompanying drawings. A brief description of the drawings follows.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a heat exchanger according to a first preferred embodiment of the present invention;
FIG. 2 is a side, partially cut-away view of the heat exchanger of FIG. 1 ;
FIG. 3 is a perspective view of an insert according to a second preferred embodiment of the present invention, the insert being a component of the heat exchanger of FIG. 1 ;
FIG. 4 is a view, similar to FIG. 2 , of a heat exchanger according to a third preferred embodiment of the present invention;
FIG. 5 is a view, similar to a portion of FIG. 2 , of a heat exchanger according to a fourth preferred embodiment of the present invention;
FIG. 6 is a perspective view, similar to FIG. 3 , of an insert according to a fifth preferred embodiment of the present invention;
FIG. 7 is an exploded perspective view of the insert of FIG. 6 ; and
FIG. 8 is a view, similar to FIG. 2 , of a heat exchanger according to a sixth preferred embodiment of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 shows a heat exchanger 20 according to a first preferred embodiment of the present invention.
FIG. 2 is a side, partially cut-away view of the heat exchanger 20 of FIG. 1 . From FIG. 2 , it can be seen that the heat exchanger 20 comprises a fluid device in the form of a heat exchange element 22 . The heat exchanger 20 also comprises an insert 24 .
The heat exchange element 22 is for use as part of a coolant circuit (not shown) and as part of an oil circuit (not shown) and is of the donut type. That is, it includes a central aperture 26 (delineated in phantom outline in FIG. 2 ), to permit mounting on a threaded pipe attached to an engine block (neither shown). This permits the subsequent threaded engagement of an oil filter (also not shown) onto the pipe, to hold the heat exchange element 22 in place against the engine block. It should be understood that other configurations are possible. For example, the heat exchange element need not be of the donut type. As well, the heat exchange element could be an air-cooled radiator, in which event a liquid coolant circuit would not be involved therewith in use. Further, the heat exchange element could be used for cooling or heating fluids other than oil. Additionally, the heat exchange element could be for use as part of multiple heating or cooling circuits and/or multiple oil circuits.
Preferably, the heat exchange element 22 is of the stacked-plate type, comprising a plurality of plates 28 of aluminum, brazed to one another. The plates are arranged back-to-back into plate pairs. The plates 28 have apertures 30 formed therein. The apertures 30 are ringed or encircled by raised bosses 32 , and when the plates 28 are stacked against one another into the plate pairs, the bosses are opposite facing with the apertures 30 and the bosses 32 aligned. The bosses 32 thus form a pair of spaced-apart manifolds 34 , 34 ′ which each define a respective flow distribution passage 36 , 36 ′.
Each manifold 34 , 34 ′ has a respective central, longitudinal axis A-A. The peripheral edges of apertures 30 in abutting bosses 32 define a plurality of axially or spaced-apart annular ridges 38 projecting into the flow distribution passages 36 , 36 ′. The annular ridges 38 , in turn, define therebetween a plurality of axially or longitudinally spaced-apart annular recesses or channels 40 , which also form parts of the flow distribution passages 36 , 36 ′. The bosses 32 form peripheral walls of the manifolds 34 , 34 ′. The manifolds 34 , 34 ′ are coupled to one another in heat exchanging relation such that, in use, upon a flow of heated oil being forced into one of the manifolds 34 , 34 ′, a flow of cooled oil issues from the other of the manifolds 34 , 34 ′. Such coupling is effected in this embodiment by a plurality of heat exchange fluid flow passages or oil passages, shown in phantom in FIG. 2 and identified with reference numerals 42 , formed by the plate pairs. For greater clarity, it should be understood that in this preferred embodiment, the heat exchange flow passages 42 extend between the manifolds 34 , 34 ′ encircling the central aperture 26 in a split flow configuration. Again, other configurations are possible.
With continuing reference to FIG. 2 , the donut cooler 20 also comprises a top plate 44 and a bottom plate 46 . The top plate 44 has ports 48 , 50 formed therethrough communicating with respective upper ends of manifolds 34 , 34 ′, and includes a flat surface 52 for sealingly receiving the base of an oil filter. The bottom plate 46 has a single port 54 therethrough which communicates with the bottom end of manifold 34 ′.
It should be understood that the heat exchange element 22 is of generally conventional construction, and therefore, only those parts necessary for an understanding of the present invention are shown in the figures and/or described hereinbefore.
Turning now to FIG. 3 , the insert 24 includes a cradle 56 . The cradle 56 comprises a base portion 58 , a peripheral wall portion 60 and spaced-apart, resilient fingers 62 . The peripheral wall portion 60 is dimensioned for disposition in sliding but snug-fitting relation within a respective annular ridge 38 in FIG. 2 . The base portion 58 spans the peripheral wall portion 60 , to check or block flow therethrough. The fingers 62 are four in number, although greater or lesser numbers can be employed, and extend outwardly from the peripheral wall portion 60 in opposed relation to one another. Each finger 62 has a V-shaped tab portion 64 , the tab portion 64 having an apex that extends outwardly. Fingers 62 are resiliently deformable from an outwardly disposed arrangement as seen in FIGS. 2 and 3 , to an inwardly deformable arrangement. In the inwardly deformable arrangement, the fingers 62 are compressed toward one another, such that the width of the insert 24 is smaller in dimension than the ports 48 , 50 , 54 and the apertures 30 , so that insert 24 can pass therethrough. In the non-compressed or outwardly disposed arrangement, the fingers 62 extend outwardly, as shown in FIG. 3 , such that the width of the insert 24 is larger in dimension than the ports 48 , 50 , 54 and the plate apertures 30 , as described next below.
The foregoing structure permits the ready construction of heat exchangers having any desired number of passes from a common heat exchange element, merely by suitably positioning inserts 24 into the manifolds thereof. Such positioning of the inserts is conveniently effected by passing the inserts through a desired port 48 , 50 , 54 using a suitable tool (not shown), and then pushing the insert through the respective manifold to a desired depth. In this process, the fingers 62 are forced inwardly into their inwardly deformed arrangement as each port 48 , 50 , 54 or annular ridge 38 is passed by the V-shaped tab portions 64 , and the fingers 62 spring or snap outwardly to their non-compressed or outwardly disposed arrangement with the V-shaped tabs 64 engaging opposed recesses 40 in the manifolds, to retain the insert in the location desired.
The heat exchanger of FIG. 2 is an example of a single pass heat exchanger constructed in this manner. As is evident, in this embodiment, a single insert 24 is provided. The peripheral wall portion 60 of such insert 24 is disposed in snug-fitting relation within an upper annular ridge 38 of manifold 34 ′. The insert 24 , and more particularly, the base portion 58 thereof, thus stops or blocks flow from flow distribution passage 36 ′ through port 50 when disposed in this terminal location in the manifold 34 ′. As will also be seen, as so positioned, the fingers 62 releasably engage the uppermost of the annular recesses or channels 40 , to lock the insert 24 in this operative position. It will be understood that the portions of the annular recess 40 in which fingers 62 are located are considered to be opposed recesses for the purposes of this specification. Such opposing location of said recesses serves to lock the insert 24 against axial movement. Discrete opposed recesses (not shown) or sockets may be provided in the place of annular recesses 40 , if desired. For example, if the base portion 58 of insert 24 was circular, it may be advantageous to provide discrete recesses for the fingers, to resist rotation of insert 24 .
In use, oil from an engine block (or another heat exchange fluid) is received into manifold 34 ′ through port 54 in the bottom plate 46 . The insert 24 blocks flow through port 50 . This forces oil introduced into manifold 34 ′ to flow through oil passages 42 . Oil exiting from the oil passages 42 is collected by manifold 34 and exits through aperture 48 in the top plate and into an oil filter, for example, and subsequent return through the central aperture 26 as mentioned above. It will be evident that a device with similar functionality could be obtained by omitting bottom plate 46 , and fitting an additional insert in the lowermost position of manifold 34 . Top plate 44 could also be omitted. As well, it should also be apparent that the device could function equally well if flow was reversed, that is, if flow was received from a filter or other device into manifold 34 via port 48 . In such situation, the flow would flow through the oil passages 42 , be collected in manifold 34 ′, and then exit the heat exchanger through port 54 .
FIG. 4 shows a two-pass heat exchanger 20 ′. In this heat exchanger 20 ′, the heat exchange element 22 is identical to that provided in FIG. 2 , but includes two inserts 24 , disposed respectively at the upper end of manifold 34 , and at an intermediate location in manifold 34 ′. The former insert 24 blocks flow through port 48 . The latter insert 24 separates the plurality of oil passages 42 into two oil flow subpaths, A and B, as indicated in FIG. 4 , which are connected in series to one another, each subpath A, B being composed of a group of oil passages 42 connected in parallel to one another. In use, oil is received into manifold 34 ′ through port 54 and channeled by subpath “A” to manifold 34 . From manifold 34 , the oil is channeled back to manifold 34 ′ by subpath “B”, and then issues through port 50 in the top plate 44 . Of course, flow patterns can be reversed herein as well, and the top plate and/or bottom plate can be omitted as discussed above.
FIG. 5 shows a three-pass heat exchanger 20 ″. In this heat exchanger 20 ″, the heat exchange element 22 is identical to that provided in FIG. 2 , but includes three inserts 24 , disposed respectively at the upper end of manifold 34 ′, and at intermediate locations in manifolds 34 and 34 ′. The insert disposed at the upper end of manifold 34 ′ blocks flow through port 50 . The inserts 24 disposed at intermediate locations separate the plurality of oil passages 42 into three oil flow subpaths, A, B, C connected in series to one another, each subpath A, B, C being composed of a group of oil passages 42 connected in parallel to one another. In use, oil is received into manifold 34 ′ through port 54 and channeled by subpath “C” to manifold 34 . From manifold 34 , the oil is channeled back to manifold 34 ′ by subpath “B”. Finally, oil received into manifold 34 ′ from subpath “B” is channeled back to manifold 34 by subpath “A”/and ultimately issues through port 48 in top plate 44 . Again, flow patterns can be reversed herein, and the top plate and/or bottom plate can be omitted as discussed above.
Referring next to FIGS. 6 and 7 , a modified insert 24 ′ according to a fourth preferred embodiment of the present invention will next be described. FIG. 7 is an exploded view of the insert 24 ′ of FIG. 6 . This insert 24 ′ is similar in structure to insert 24 (similar parts being identified with like reference numerals). However, in this insert 24 ′, the base portion 58 defines a fluid port 66 to allow flow therethrough. Further, this insert 24 ′ additionally includes a flapper 68 . The flapper 68 preferably is stamped from spring steel and has a mounting part 70 and a resilient hinged tongue part 72 . The mounting part 70 is secured to the cradle 56 by a standard rivet 74 . The tongue part 72 extends away from the mounting part 70 and includes a transverse corrugation 76 . Corrugation 76 is optional. The corrugation 76 helps to bias the flapper 68 to assume a fluid tight closed configuration, wherein the tongue part 72 is disposed at a closed position whereat it abuts and bears against the cradle base portion 58 to cover fluid port 66 , as shown in FIG. 6 . The tongue part 72 is dimensioned to restrict, and more specifically, substantially arrest flow through the fluid port 66 when the flapper 68 is so disposed. However, tongue part 72 can be shaped or dimensioned to restrict or block only a portion of fluid port 66 where it is desired to have some seepage or trickle flow through insert 24 ′. The tongue part 72 is movable by flexure of the tongue part 72 from the closed position at least partially closing fluid port 66 , to an open position, whereat the tongue part 72 is spaced from the fluid port 66 to permit flow therethrough. Usually this occurs when in cold start-up conditions, where there is high fluid pressure on the underside of insert 24 ′, but it could also occur if there is a pressure spike in the oil circuit unrelated to oil temperature. The closed and open positions of the tongue part 72 respectively define closed and open configurations of the flapper 68 . Flapper 68 could also be made of bimetallic material, as described further below.
Inserts of this type can be deployed to great advantage. For example, an insert 24 ′ of this type could be deployed in the structure of FIG. 2 , in place of the insert 24 shown therein, and the spring bias of the flapper 68 could be selected to substantially arrest flow through the fluid port 66 in normal operating conditions, yet allow flow through fluid port 66 when the pressure drop across insert 24 ′ exceeds a predetermined value. This would provide selective cold flow bypass of or through the heat exchanger 20 . That is, in normal operating conditions, wherein relatively warm, substantially free-flowing oil is delivered to manifold 34 ′, the spring constant of the flapper 68 would keep the tongue part 72 in its closed position against the base portion 58 to restrict, and more specifically, substantially arrest or stop flow through fluid port 66 . Thus, most of the flow arriving at manifold 34 ′ would pass in heat exchanging relation through the oil passages 42 to manifold 34 prior to passing through port 48 . In contrast, in conditions such as cold start-up in relatively cold ambient conditions, wherein the oil is relatively cold, highly viscous oil is delivered to manifold 34 ′. In these circumstances, the flow resistance through the oil passages 42 is relatively high, with the result that the viscous oil would force the tongue part 72 to its open position, above the base portion 58 , to permit flow from manifold 34 ′ through port 50 . That is, bypass flow would occur. The foregoing structure is of particular advantage, in that it obtains relatively high cooling performance in normal operating conditions, when cooling is needed, as substantially all oil passes through the heat exchange element. At the same time, the structure avoids starvation of mechanical components in normal transient high pressure conditions, such as cold weather start-up, and also avoids metal fatigue that can result from pressure spikes in the thin-wall plates forming the heat exchanger, since in such conditions bypass flow occurs.
As a further, non-limiting example, inserts 24 ′ of this type could be deployed in the structure of FIG. 5 , in place of the inserts 24 shown therein, with the spring bias of the flappers 68 thereof selected to provide sequential bypass. That is, in normal operating conditions, flow through the heat exchanger 20 ″ would be as shown in FIG. 5 , i.e. the oil flow would be forced sequentially through subpaths C, B, A. In slightly elevated pressure conditions, the flapper 68 of the uppermost insert in manifold 34 ′ would open, thereby to permit a portion of the flow to bypass oil subpath A, i.e. such that all of the oil would be forced only through subpaths C, B, and very little, if any, would pass through subpath A. In moderately elevated pressure conditions, the flapper 68 of the insert in manifold 34 would also open, thereby to permit a portion of the flow to bypass oil subpath B i.e. all the oil would be forced only through subpath C, and very little, if any, would pass through subpaths B, A. In highly elevated pressure conditions, the flapper 68 of the lowermost insert in manifold 34 ′ would further open, thereby to permit most, if not all, of the oil to bypass subpaths A, B, C, i.e. the oil would not be forced to flow through any high-resistance portion of the heat exchanger. This arrangement would tend to avoid pressure-related damage to the heat exchanger, while at the same time, maintaining heat transfer functionality except under conditions of very high pressure.
It will be appreciated that the more passes a heat exchanger has, the higher will be the heat transfer of the heat exchanger, but the pressure drop across the heat exchanger also increases with more passes. With the present invention, the heat transfer and pressure drop characteristics of the heat exchanger can be designed to suit end user needs, simply by modifying the characteristics of the inserts.
As yet a further alternative, the flappers 68 can take the form of a bimetallic strip or coil, adapted to move in response to temperature variations. For example, the bimetallic characteristics could be chosen to allow full bypass flow in cold start-up conditions, and gradually reduce the bypass flow as the oil heats up and becomes less viscous such as at normal operating conditions.
FIG. 8 shows a heat exchanger 20 ′″ similar to the heat exchanger of FIG. 5 . However, in this heat exchanger, modified inserts 24 ″ with bimetallic strip flappers 80 are substituted for the inserts 24 disposed at intermediate positions in the manifolds 34 , 34 ′. As well, an insert 24 ′ is substituted for the insert 24 disposed at the upper end of manifold 34 ′, although this could be a bimetallic insert 24 ″ as well. The bimetallic strip flappers 80 are constructed so as to assume the open configuration at temperatures significantly below normal operating conditions, and to assume the closed configuration at temperatures at or above normal operating conditions. This heat exchanger 20 ′″ could have selective cold flow bypass characteristics, in that it could operate as a single-pass configuration in cold or below normal temperature flow conditions, as shown in FIG. 8 , and switch automatically to a three-pass configuration (i.e. the flow pattern shown in FIG. 5 ) in normal or abnormally hot conditions. Of course, any configuration in between could be obtained by choosing the characteristics of the bimetallic flapper appropriately. Further, by mixing the inserts 24 ′ and 24 ″, heat exchanger 20 ′″ could have both pressure responsive and temperature responsive characteristics, as desired.
Having described the preferred embodiments of the present invention, it will be appreciated that various modifications may be made to the structures described above without departing from the spirit or scope of the invention.
For example, whereas the present disclosure is directed largely to heat exchangers, it should be understood that the invention is not so limited. Inserts according to the present invention may be deployed in association with any fluid device defining a flow distribution passage and further defining a peripheral wall with opposed recesses that the insert can engage to be retained in position. The invention could, of course, be used with any type of fluids.
It will also be appreciated that other combinations of normally closed inserts 24 and inserts with bypass flappers 24 ′ and inserts with bimetallic flappers 24 ″ can be used to give a variety of flow configurations, in different operating conditions, inside the fluid devices.
Further, whereas the heat exchange element shown has a plurality of axially-spaced channels or opposed recesses, this need not be the case; the insert can be used with a heat exchanger having only one such channel or one pair or set of opposed recesses.
It should also be understood that whereas the disclosure illustrates and describes heat exchangers of generally similar construction, modifications therein are also contemplated to fall within the scope of the invention.
For example, the heat exchangers need not be formed of stacked plates, nor is it required that all or any of the various components be brazed to one another. The plates forming the heat exchanger could, for example, be made of other material, such as plastics, or they could be secured to one another with a suitable adhesive, such as epoxy. Tubes could be used instead of plate pairs to define some or all of the flow passages.
Further, whereas the flapper tongue parts illustrated in the preferred embodiments are substantially planar, it will be evident that this need not be the case, and any form of protuberance could be formed to fit, in whole or in part, in the fluid port 66 .
As well, the construction of the flapper need not be limited to a single material. The mounting part could be made of a different material than that of the tongue part. Coatings could also be applied to assist in sealing, especially if the flapper is made of a weaker spring material.
If desired, the finger tab portions 64 could be lengthened a bit and holes formed in them, so the fingers could be gripped by a suitable tool (not shown). This would allow the fingers to be deformed inwardly by the tool so that the inserts 24 could be relocated or removed, as desired.
Finally, the insert can be located facing up, as described, or turned upside down, to suit the direction of flow through the heat exchanger or other fluid device with which it is used. | An insert snaps into position in a manifold of a fluid device to perform a baffling function. The insert includes a cradle having a base portion and opposed spring fingers for retaining the insert in position. The base portion can be completely closed to prevent flow through the insert, or have a spring flapper valve or bimetallic flapper valve to permit partial or full flow through the insert under predetermined conditions. | 8 |
BACKGROUND OF INVENTION
(1) Field of Invention
The present invention relates to cluster bombs and more specifically to a bomb assembly, comprising a cylindrical casing adapted to contain a cargo of munitions and a safer and simpler system for the ejection and dispersal of these munitions from the cluster bomb.
(2) Description of Related Art
Clustered bombs have been used extensively in trying to increase the effectiveness of air dropped munitions. These have been used since prior to World War II and basically involved the combination of a number of smaller bombs held together by some frangible or breakable link. These could be dropped together and would separate at the time of drop or during the descent so that they would have separated in distance from each other in the air and retain the capability, individually to damage or destroy the targets which they hit or which were in their area. U.S. Pat. No. 2,604,043 shows an example of such clustered bombs and the manner in which they were held together and subsequently were permitted to separate.
Parachutes have been used for retarding bombs and have been used to initiate the drop of repeated single parachute bombs, wherein a detent mechanism accomplishes that release as shown in U.S. Pat. No. 2,317,256.
Similarly large canisters were rear ejected from a main, still larger container by the release of a parachute, pulling out one canister which is hooked to a static line to the next parachute, pulling this out, to further pull out the next canister, and so on. This is shown in U.S. Pat. No. 3,940,443.
In still another patent, bomb clusters have been opened during the deployment of a parachute where the downward fall of the cluster opening permitted some dispersion of the small numbers of bombs in the cluster as shown in U.S. Pat. No. 2,874,639.
All of the above involved bomb clusters which were in free fall and which opened after that downward free fall and gave some dispersion to the few bombs of the cluster.
In time, it became apparent that it would be more advantageous to further reduce the size of these smaller bombs since computations, dating back to Leonardo DaVinci showed that anti-personnel effectiveness could be greatly improved by accomplishing this. Studies after World War II had shown that relatively small bombs, considerably smaller than those used in clustered bombs, could destroy tanks, armored vehicles, trucks and similar military vehicles. It soon became apparent that it was difficult and costly to place such larger numbers of much smaller bombs in clusters and reliably and safely hold them together for aircraft drop. This led to the placement of such clustered smaller bombs within the confines of a larger bomb, acting as a container for the smaller bombs, where, after drop from the aircraft, the bomb would open and somehow disperse the cargo of the contained smaller bombs over a target area. An example of this is U.S. Pat. No. 2,809,583.
The initial and continuing problem in trying to accomplish the ejection and dispersion of the cargo of such larger bombs has been the means of accomplishing this objective. Actually, two types of clustered dispensing systems came into being. One is commonly known in the U.S. as Slung Under Unit Dispensers or SUU Dispensers. These are hung under aircraft and directly used to dispense a cargo of munitions, through RAM air or propellants with the dispenser container retained on the aircraft. The United States Air Force has been using such SUU dispensers extensively. Here smaller bombs or other munitions are dispensed usually out of the rear end of SUU dispensers as a result of forces applied against the cargo to cause it to eject rearward. Thus Ram air was used frequently to eject the cargo of munitions as is shown in U.S. Pat. No. 3,308,719.
In a related application, such dispensers were replaced by a nest of rocket launcher tubes that may cluster a larger number of rocket launchers to propel or project rockets in the forward direction at the target. The 2.75 inch rocket launcher system used on aircraft is the best of such examples. See also U.S. Pat. No. 3,269,268.
The United States Navy was of the opinion that the aircraft dispensing of munitions, requiring a flight over the target would result in excessive losses to enemy air defenses. The Navy consequently developed an alternate form of dispensing clustered munitions, which would not require a flight over the target. Instead of leaving the dispenser on the aircraft during the dispensing of the munition, the dispenser itself was dropped from the aircraft and designed in a missile configuration, so as to fly toward the target, while the aircraft would turn so as to permit the aircraft to be out of gun reach of the defending gun positions. In one tactical use, this dispenser, which is now known as a cluster bomb, would be dropped from great altitudes at long distances from the target where the aircraft was out of reach of most air defense weapons. The forward velocity of the aircraft would to a large extent be retained by the aerodynamically shaped cluster bomb and would permit it to fly a long distance in the direction of the target before the cargo of munitions would be dispensed from that bomb to cover all or part of the target area.
In a second tactical use the aircraft would be flying at a low altitude. As it approached the target area, it would fly upward and release the cluster bomb on the "up-leg" of flight. This upward angle of flight of the cluster bomb would cause it to fly in a mortar shaped flight configuration. The cluster bomb, which is in effect a missile would fly a considerable distance toward the target area, to discharge the cargo of submunitions over the target area. The aircraft would turn and not be required to fly over the target area.
A major problem in the design of a cluster bomb as described above involved the complexity and resulting cost, as well the safety of such bombs. A cluster bomb had to be fuzed such that the dispensing of smaller bombs, mines or grenades could be conducted efficiently and reliably. Consequently, various designs of the cluster bomb were produced to properly contain and be able to discharge the cargo of munitions. These designs used a number of basic techniques, including combinations of such techniques to eject and disperse the cargo of munitions. This required the packing of the munitions such that they could be dispersed from the cluster bomb without damage. It further was a desire to pack the maximum cargo of munitions within the cluster bomb. As a result of these objectives a number of cluster bomb designs were produced and patented. Some initial designs used a simple unthreading means of the clamping means provided by a turbine to open the cluster and release the cargo. (U.S. Pat. No. 2,450,910). This was unsatisfactory since the timing of release became important. Consequently new designs were made which, could be used with time fuzes and which at a preset time of the fuze, would cause the ejection and discharge of the cargo.
A large number of ways of opening up of the cluster bomb to disperse the cargo of munitions were devised. Gas pressure was used to break open a frangible jacket (U.S. Pat. No. 2,802,396). The skin was removed by explosives in the form of linear shaped charges (U.S. Pat. No. 2,996,985). This is used in the U.S. Rockeye II Cluster Bomb. The casing of the bomb was destroyed by pyrotechnic material (U.S. Pat. No. 3,016,011). Hot gas was used in a piston ejection system (U.S. Pat. No. 3,295,444). In related clustered rocket pods used on aircraft these used propellant projection of the individual rockets (The 2.75 inch rocket system which was under a U.S. Project Manager is an example of such a clustered weapon system). Bomblets have been dispersed through the ogive of such rockets (U.S. Pat. No. 4,488,488). Submissiled air to surface warheads, which closely resemble cluster bombs used a propellant diaphragm deployment mechanism for dispersing the cargo of munitions (U.S. Pat. No. 3,865,034). Gas generating foam was placed between the munitions, to disperse the same on ignition (U.S. Pat. No. 4,063,508). High speed spin as a result of propellant burning was another means of dispersing the cargo of munitions (U.S. Pat. No. 4,488,489). Ejection of subunits containing a cargo of munitions from a guided missile was still another dispensing technique (U.S. Pat. No. 4,498,393). In the case of munitions having a circular cross section a sudden change of acceleration or deceleration produced by propellants is used to eject the cargo sideways from a plurality of receptacles arranged such as to induce spin (U.S. Pat. No. 4,555,971).
The following prior art discussed below is also to be considered in relation into this invention: U.S. Pat. Nos. 4,005,655, 4,273,048.
U.S. Pat. No. 2,317,256 involves a cluster of bombs dropped from an aircraft. A parachute is used to retard the descent of the container containing that cluster. The bomb is adapted to automatically and sequentially at predetermined intervals, release the bombs so as to drop these bombs over a wide area.
U.S. Pat. No. 2,874,639 involves a bomb which deploys a parachute and on deployment of that parachute ejects a package of cargo out of the nose section. This does not involve the dispersion of the cargo itself, which is the subject of the instant invention.
U.S. Pat. No. 4,005,655 shows the use of an inflatable stabilizer/retarder to slow down the flight of a bomb. This involves a flexible, inflatable, conical shaped bag which is stored in the tail segment of the bomb for deployment where a high drag mode of operation for the weapon is required. It is also small in size and inexpensive.
U.S. Pat. No. 4,273,048 shows a mine field clearance round where a parachute is deployed from the tail section to slow down and orient the same so as to face down.
U.S. Pat. No. 4,488,488 shows a parachute projection system for submunitions which are explosively projected through the ogive of a rocket over a tank containing area. The explosive projection created severe problems which U.S. Pat. No. 4,488,488 attempted to overcome, while retaining the explosive projection. The elimination of any explosive projection is one of the basic objectives of the instant invention.
U.S. Pat. No. 4,498,393 shows the ejection of dispensing units from rockets or shells using parachutes to slow down these dispensing units. These subsequently further dispense a cargo of mines, bomblets or subsidiary projectiles in order to obtain the desired dispersion of this cargo of munitions. Here the ejection of these dispensing units is obtained by either strongly braking the dispensing units or instead braking the carrier, so as to eject the dispensing units whether through the tail or the nose section. This is not used to obtain dispersion. It is used to obtain the ejection and to prevent impact between the carrier and the dispensing units.
U.S. Pat. No. 4,555,971 shows the use of propellants to accelerate or decelerate a carrier projectile and to eject, side launch and disperse the contained cargo of submunitions from rifled tubes within the carrier projectile. It teaches the use of acceleration or deceleration to launch such submunitions, but depends on chemical propellants to achieve this. It further requires complex rifled tubing in order to obtain the desired objectives. It is the use of propellants and the complexity of such devices which the instant invention is designed to overcome.
All of the prior stated methods of producing ejection and satisfactory dispersion systems for their cargo of submunitions suffer in that most involve complex and costly designs, difficult to manufacture. Most use explosives, propellants, pyrotechnic or gas producing systems to expel the cargo and to provide tangential velocity so as to disperse the cargo.
Any energetic material has the potential of deteriorating in storage or handling such that it becomes inoperable. This is especially applicable where these energetic materials are chemical disperal systems and are subjected to higher temperatures, high humidity conditions such as would be found in the storage compartments of ships and in tropical areas, where these cluster bombs are frequently used. All energetic materials pose a degree of danger in storage, handling and in use on air-craft.
There has been a continuous desire to produce lower cost, easier to fabricate and safer to handle cluster bombs. Normally, the container main body of cluster bombs are fabricated from metal or plastic components and, therefore, cluster bombs can be manufactured competitively in a very large number of industrial organizations. Competition drives the cost down to a minimal amount. But, once energetic materials, such as propellants, explosives or pyrotective materials must be attached to that body or container, then the competition is effectively eliminated since only one or two special facilities in the locality can handle such energetic materials. Governmental restrictions severely limit the licenses given out to organizations authorized to handle explosives, propellants or pyrotechnic materials. These organizations need extra land and special facilities to store these energetic materials. Operators need special training and receive higher pay. Storage, handling and transportation requirements are severe and increase costs. There is always the potential of accidents with explosives, propellants or pyrotechnic materials. This forces special handling of loaded items. Even cluster bomb bodies containing small amounts of explosives require special handling and escort of police or similar protection during transportation, especially across bridges and through tunnels. All of these considerations cause a higher cost for energetically loaded cluster bomb bodies as compared to inert bodies which do not contain explosives or propellants.
Cost becomes an important consideration when extensive competition in international sales of cluster bombs occurs. Thus, companies in countries such as France, England, Israel and the United States compete for international sales of cluster bombs containing dual purpose, anti-tank, anti-personnel bomblets to countries which had conflicts with other countries and needed such cluster bombs for their defense. The result of these considerations has been that a need exists for cluster bombs, whose bodies could be manufactured without explosives, propellants or pyrotechnic materials so as to reduce the prior stated cost in transportation and manufacturing and to overcome safety problems. Similarly, complex designs could not be used since costs would be excessive.
It is consequently an objective of this invention to overcome the prior higher cost of fabrication of such bombs and the inherent safety problems that result from the energetic, propellant, pyrotechnic or explosive content used in some bombs to release the cargo of munitions. It is another objective of this invention to provide for a cluster bomb that does not require energetic materials to discharge and/or disperse the munitions, yet retaining the prior dispersion pattern of those cluster bombs, but thereby increasing the safety and reliability of such cluster bombs. It is further another objective of this invention to provide for a cluster bomb which is simpler in construction and therefore easier to manufacture than prior art bombs and yet able to disperse in a proper pattern a cargo of anti-tank, anti-personnel, dual purpose bomblets. Here, in fact, incendiary action has been added to result in a multi-purpose bomblet.
Consequently one object of this invention is to provide for a body or container for the submunition cargo that could be totally devoid of any energetic material during the manufacture and transportation thereof to the loading plant. This would provide for a much lower cost of fabrication, transportation and storage thereof. Lacking such energetic materials increased safety in manufacture, transportation and storage of such bodies or containers can take place. A further objective was to eliminate all explosives, propellant and pyrotechnic materials other than those normally contained in initiators, detonators or low energy detonating cord from the cluster bombs, since propellants and pyrotechnic material are deteriorated by higher temperature and higher humidity conditions, their elimination increases the high temperature and high humidity storage characteristics of the cluster bombs. Eliminating the larger amounts of all of these energetic and consequently hazardous marterials increases the safety in the use of the cluster bombs of this invention since malfunctioning would result in "failsafe" performance, rather than a more hazardous energetic event.
Yet, in spite of these advantages, which drive costs down and provide for a much safer to use cluster bomb, this invention provides a mechanism of retaining the dispersion or dispersal capability of the prior art, which is obtained in the prior art by complex and costly dispersal systems employing spin and energetic ejection systems. The present invention obtains the dispersion by ejecting the bomblets through the nose section, while the body or container is retarded and pulled away from the bomblets. The bomblets traveling at a high speed forward velocity upon entering the windstream can only be deflected outwardly as a result of their dense packing in the cluster bomb. This causes the bomblets to angle their direction off-axis with respect to the flight of the cluster bomb and to disperse, resulting in a dispersal pattern which is equivalent to that obtained by the prior art.
In the prior art, where spin and explosive dispersion was used, the load of bomblets were ejected sideways, while the axis was parallel with the cluster's longitudinal axis. This resulted in high drag forces to be exerted on the bomblets and reduced the side dispersion. In the present "forward projection mode" this is no longer the case and results in a dispersion equivalent to this prior art, but without the complexity.
SUMMARY
This invention pertains to cluster bombs and is an improvement in the construction from the point of view of safety and economical fabrication, while maintaining the desired cargo dispersal patterns on the target equal to that achieved by the prior art.
Where most such prior bombs needed propellant, pyrotechnic or explosive dissemination of their "pay load" of munition sub-units, which could consist of bomblets, mines, grenades or missiles, this is no longer the case here and simplifies the fabrication process. This cargo of ammunition can be delivered, deployed or ejected from cluster bombs, rockets or missiles in the air, over target area. Where the potential existed that the propellant or explosive disseminating system might accidentally malfunction and cause serious damage in fabrication, storage, transportation or when used on the aircraft, this is no longer the case in this invention which eliminates such energetic dissemination material and relies instead on a novel mechanical disseminating process.
In the cluster bomb of the instant invention, the functioning of a time fuze transmits a signal (or activation) to the tail stabilizer section which contains within it a drag means, which is activated. The drag means is deployed and suddenly "brakes" or slows down the bomb and causes the munition cargo located in the body or container section to shift or move toward the nose area. Simultaneously, or prior to this braking or slowing down action, the front end of the bomb is opened in any of large number of ways. In the instant invention, a cylindrical body or container is also used to contain the munition cargo, so as to permit these munitions uninterfered ejection out of the cluster bomb as a result of their own inertia during the sudden slowing down of the cylindrical container of the cluster bomb and the near simultaneous opening and discarding of the entire nose section to permit the munition cargo to exit and to be dispersed by the onrushing airstream. Ejection of the cargo is accomplished by the sudden slowing down of the air born cluster bomb, rocket or missile. This causes the munition cargo in the foam packing in which it is contained to set forward and exit through the nose section, the nose section having been either previously opened or opened in the process. The opening of the nose section may be accomplished by the cargo directly, by a separate inertial mass, or both. Or the nose cone can be forced open by other means. Thus the nose section may be weakened to yield to the force of the cargo, the inertial mass, or other means, as the body or container is suddenly slowed down. When this happens, the inertial mass and/or the cargo of bomblets sets forward moving to the nose section.
The sudden slowing down of the cluster bomb, rocket or missile is preferably accomplished by an inflatable stabilizer drag retarder deployed from the tail section, (A drag device, which is especially applicable to this invention is described in U.S. Pat. No. 4,005,655) of sufficient size such that it imparts a sudden deceleration to the cargo of munition of sufficient magnitude as to overcome the combined holding forces of inertia, that of the packaging materials and incident air and to overcome the pressures from the inrushing air through the open nose, so as to cause that cargo to set forward, and move and exit through the nose section. As noted in said patent, such inflatable stabilizers are small in size and inexpensive to fabricate.
The slowing down of the cluster bomb, rocket or missile can be accomplished by drag devices such as a conventional parachute, a rotating parachute, a combination of a pilot parachute and a main parachute or an inflatable stabilizer/retarder. Alternatively, slowing-down can be accomplished by the deployment of retrorocket propulsion of sufficient force to cause the shear of the cargo of ammunition from the container walls and to overcome inertia, and to be of sufficient impulse (long enough duration time of that force) to cause all of the cargo to shift forward toward the nose section and exit through the nose section before the retrorocket propellant has burned out.
The nose section can be opened either by the initial fuze action providing energetic forces to open that section through explosives, propellant or pyrotechnic means or, instead, where a spring loaded mechanism is activated to open that nose section, either from the rear or directly located in the nose section and where the same is activated subsequent to the fuze action. Thus explosives can be used directly to blow the nose section apart by using, for example "sheet explosive" on the inside of the nose sections. Propellant charges could be used to blow the panels of the nose section outwards. Neither of these processes would have any deleterious effect on the bomb body or container. Pyrotechnic materials could be used to cut the nose section apart, so as to have it fall away from the bomb. While less desireable than the preferred embodiments, these are available options for opening of the nose section. The nose section in the preferred embodiments is divided such that it will rupture after fuze action and the forces being applied to that section will split it apart, and the nose section is further opened by aero-dynamic pressure of the incident onrushing air so as to open to the full diameter of the munition cargo containing cylindrical body, so as to permit ejection of the munition cargo thereof through this open nose section.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a longitudinal, axial, sectional view through a cluster bomb assembly of a preferred embodiment A of this invention.
FIG. 2, detail "I" is a detailed longitudinal, axial, sectional view of the nose section of preferred embodiment A detailed as "I" in FIG. 1.
FIG. 3, is a detailed longitudinal, axial, sectional view of the base end section of this preferred embodiment detailed as "II" in FIG. 1.
FIG. 4, is an axial, cross sectional view of segment AA of FIG. 1, at section A--A.
FIG. 5, is an axial cross sectional view of section B--B in FIG. 1.
FIG. 6 shows the opening of the closure of the parachute compartment and the initial release of the drag device or parachute.
FIG. 7 shows the cluster bomb shortly after deployment of the inflatable stabilizer/retarder of the embodiments and the discarding of the nose section.
FIG. 8 is a longitudinal, axial, sectional view through a cluster bomb assembly of another preferred embodiment, B, of this invention.
FIG. 9 shows the spring loaded mechanism used to open the nose section upon withdrawal of two pins holding the mechanism from performing that function and which is shown as segment "IV" in FIG. 8.
FIG. 10 is a longitudinal sectional view of segment "III" in FIG. 8 showing the open hinged nose section on opening and just before separation from the remaining cluster bomb.
FIG. 11A shows details of sectional view of segment "V" of FIG. 8 showing the spring loaded cable or lanyard system in the base used to open the closure and to release the parachute, or inflatable stabilizer/retarder. The FIG. 11A is a split view which shows the system before functioning, while FIG. 11B is a split view showing the system shortly after functioning.
FIGS. 12A and 12B show two 90° apart sectional views along the longitudinal axis of the tail segment spring loaded release mechanism used to open the tail end closure shown as segment "VI" in FIG. 8.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention is a dispensing system for ejecting, for example, a cargo of anti-tank, antipersonnel, incendiary, multi-purpose munitions from a carrier cluster bomb in the preferred mode. FIG. 1, Preferred Embodiment A and FIG. 8, Preferred Embodiment B show two preferred embodiments of the invention. Both of these preferred embodiments utilize a drag device, here an inflatable stabilizer/retarder connected to the tail section of the cluster bomb. The drag device is ejected on fuze functioning out of the tail end stabilizer section during which process the nose section is opened, so that the sudden radical deceleration of the bomb causes the cargo of munitions located in the body or container to set forward and, as a result of their inertia move in the direction of the nose to exit out of the nose section and out of the cluster bomb. a. Preferred Embodiment A
FIG. 1, shows, in general, one preferred embodiment of a configuration of the dispensing system related to the carrier cluster bomb. The lugs 7 are used for suspending the cluster bomb on aircraft. Section "I" comprises the nose section, composed of a programmable time fuze 1, a nose segment 2, capable of being severed. As seen in FIG. 2 it is held together by joint 4 but capable of being forced apart by the explosion of a detonator 13, which may be a delay detonator so as to provide additional safety in case of mal-functioning of the programmable time fuze (FIG. 2). The split nose segment could very readily be composed of a larger number of segments capable of being severed. A front compartment separator or bulkhead 5 separates the nose section from the mid section cylindrical shaped body 11 of the bomb which contains the bomblet munition pay load 6. A nose end bulkhead 22 supports the fuze within the nose segments.
FIG. 5 is a horizontal cross section at point B--B of FIG. 1 showing the bomblet munition pay load 6, encased in a cushioning foam 47 (as shown in FIG. 5) contained within the cylindrical shaped body or pay load container 11. It also shows the rod 3 contained within the central tubular cylinder 20 surrounded by the pay load 6. Further shown are the lugs 7 used to suspend the cluster bomb on aircraft.
In FIG. 1, a rear end compartment separator or rear bulkhead 8 closes off the munition containing, cylindrical shaped body or pay load container 11 from the rear end, stabilizer section generally shown within "II". This segment is composed of four 90° spaced apart fins 9 and contains a parachute 12 or similar drag device, such as an inflatable stabilizer/retarder (see also FIG. 7) in a compartment 34 closed off by a closure 10. The fins 9 provide for a stable flight characteristics to prevent tumbling of the cluster bomb after launch. FIG. 4 shows a cross sectional view at point A--A of FIG. 1 of that compartment section, showing the parachute compartment cylindrical walls 34, the "parachute" 12 and the four fins 9.
The front end section of FIG. 1, "I" is detailed separately in FIG. 2. FIG. 2 shows the nose sections capable of being split, or segmented by the functioning of the detonator 13. A rod 3 extends into it and is held in a conical shaped cavity 16 within the support 17 by being connected to a conical segment 18 within the support 17. The fuze is supported by housing 14 of the nose segment which is secured in the support 17. The front bulkhead 5 of the cylindrical shaped body 11, containing the bomblet pay load 6 is held at joint 4 to the split nose sections 2. A central tubular, cylinder 20 is supported against the front bulkhead by a wedge shaped support 19 such that it fits into the interior of that cylinder and permits the rod 3 to freely pass through it. It is also held by the rear end bulkhead 8, passing through it. Central guides 23 or 24 made of washers or springs surrounding a cylindrical inner tube 21, hold the rod 3 central to the central tubular cylinder through a washer 25 or similar holding means and the wedge shaped support 19 and maintain it in that position. A frangible matrix 15 holds the segments of the nose end together. The metal rod 3 is connected or machined to have a conical section 18 which is wedged in the support 17 to that it cannot move. A detonator 13 is located in the segment of the nose that supports the rod (support 17) and prevents it from movement. The explosive power or brisance of that detonator 13 is such that it is able to destroy the segment holding the wedge shaped section 18 of the rod 3 splitting the support 17 and expanding the frangible matrix 15 causing the nose section to break apart.
Detail "II" of FIG. 1 is shown in FIG. 3. This shows the tail section that then comes into action. The rod 3 is secured within the central tubular cylinder 20 by a nut 33 against a closure 37 secured in the central tubular cylinder 20. Within that closure is located a cylindrical cavity, holding spring 38 spring loaded in a contracted condition and pushing against a metal washer 39 held by nut 33. A spring 31 is held in an expanded conditions in a stable hooked position 32 and a hinge 30 prevented from movement by washer 29 which is firmly secured to rod 3. The hinge 30 is connected to a cable or lanyard 27 running through a guide 28 to pin 42 securing the lip 41 of the closure 10 of the cylindrical wall of the parachute compartment 34 where closure 10 is hinged to compartment 34 by hinge 35 on the side opposite to pin 42.
As shown in FIG. 6, when rod 3 shown in FIG. 2 is no longer supported by the wedged segment 18 in the support 17 on the forward end because of the functioning of the detonator 13 and break-up of the support, then as shown in FIG. 6 the compressed spring 38 expands and moves the rod 3 contained within the central tubular cylinder and the connected washer 29 to impact the movable facing section or front end face 43 of the parachute compartment 34. As shown in FIG. 6. This permits the hinge 30 to tilt and now permits the spring 31 to contract and transmit that pull through cable 27 and a cable support 28 to withdraw a pin 42 which secured the lip 41 of the closure 10 thereby releasing the "parachute", an inflatable stabilizer/retarder 12 to permit it to deploy as shown in FIG. 6. The spring loaded pressure of spring 38 pushing against front end face 43 aids in opening the closure 10 and pushing the parachute 12 into the air stream. The closure 10 opens sufficiently so that the aerodynamic forces of the high velocity air catches and further opens the cover and pulls it and the attached conical shaped "parachute" into the air stream to inflate.
With reference to FIGS. 2, 3, and 6, one or more cables 26 are fixed to washer 25 located in the rear end of cylindrical inner tube 21, and extent forward toward the cylinder's front end, emerging in front of front central guide 24, and continuing rearward between central cylindrical tube 20 and the cylindrical inner tube 21, emerging through the rear end of cylinder 20, where the cables are connected to the breaking means compartment 34 front end face 43.
When the front end face 43 is pushed rearward by spring loaded rod 3, cables 26 are pulled rearward at their ends connected to front end faces 43, while their ends connected to washer 25 draw the washer against inner tube 21 so that its front end compresses the wedged shaped support 19 to help frangible nose separation.
While as shown in FIG. 6 the unlatching of the closure 10 and deployment of the "parachute" 12 is taking place, the segments of the nose section have been broken apart by the explosion of the detonator 13 and the parts of the nose section, including the fuze are fully discarded as shown in FIG. 7, prior to the time that the "parachute" inflatable stabilizer/retarder 12 has deployed. Whereafter the inertia of the bomblet munition pay load 6 of FIG. 1 causes this cargo to shift toward the nose and exit through the open front into the airstream where they are aerodynamically dispersed by that airstream. This dispersal is like that discussed in Preferred Embodiment B, next.
b. Preferred Embodiment B
FIG. 8 shows in general a longitudinal sectional view through a cluster bomb of a second preferred embodiment B of the configuration of the dispensing system thereof. The functioning of the cluster bomb, after drop from the aircraft while suspended previously by lugs 63 is provided by the programmable time fuze 51. The fuze is held to the bomb within two split nose sections 52. The two sections are open hinged, as in section "III" FIG. 8, and as in FIG. 10; 76, 77, so as to permit complete separation from the bomb, upon opening of the halve sections as shown in FIG. 10.
The output of the fuze is a detonator within the fuze 51, which is connected to low energy detonating cord 55. This low energy cord detonating contains very little explosive and when exploding fully contains the explosive power within it, so as to be incapable of doing any damage, and therefore to be completely nonhazardous in its use. This low energy detonating cord transfers the explosive energy to a detonator 84 (FIG. 11A) contained in the tail, stabilizer section and is used to cause the opening of the tail closure 59 of the tail end parachute compartment 60 which permits a retained conical shaped inflatable stabilizer/retarder 58 to be released to the air stream as shown in FIG. 11B, and be inflated.
Returning to FIG. 8 the two or more nose sections 52 are held together by weak joints 70 capable of being split and the halves separated by the release of a compressed spring mechanism shown as Section "IV" in FIG. 8.
The details of the compressed spring mechanism are shown in FIG. 9. The same consists of two plates 95 that are adhered to opposite nose sections 52. Adhered to one side is a hollowed sectional piece of a rod 101 with a cylindrical cavity configured so us to permit a rod 98 to be placed into that hollowed end. With rod 98 placed in the hole and nearly bottomed, two holes were drilled through the rod 98 of such size as to permit insertion of two pins 103 to prevent the withdrawal or the rod from the cylindrical hole. A compressed spring 100 is held in that compressed condition by a pin 99 placed in a hole through the rod 98 and by the other end where the pins 103 prevent the movement of the rod 98 from the cavity in the rod 101. On the opposite end, the plate 95 is adhered to a section of pipe 96 threaded such that it will permit the threated insertion of the rod 98 in a straight line between two opposite sections of the nose FIG. 9, 52.
The nose section is connected by the prior stated hinge system, III, FIG. 8 to the cylindrical munition compartment 53, which contains the bomblet munition pay load, 62, such as anti-armor, anti-personnel, incendiary, multi-purpose munitions. The discarding of the nose section leaves the forward bulkhead FIG. 8, 71 unsupported by the nose and permits that bulkhead to be ejected by the inertial forces of the munition cargo as the parachute is deployed and decelelerates the cluster bomb.
The packaging of the munition cargo is effectively identical to that shown in FIG. 1. The tail segment or stabilizer segment as shown in FIG. 8 is composed of four fins 56 90° apart, connected to the rear bulkhead 54 or separator from the cylindrical, munition compartment 53.
A cylindrical compartment 60 within that tail segment as shown in FIG. 8 contains the "parachute," which in the preferred embodiment is an inflatable stabilizer/retarder 58. The compartment is closed off at the tail end with a latched cover 59. The lanyard or cable 69 that connects the pins in the compressed spring, nose spreading mechanism to the parachute is shown in FIG. 8.
FIG. 11A and 11B show the details of the tail section, "V" of FIG. 8 "parachute" release mechanism before and after functioning, where that release mechanism is also more closely shown in FIGS. 12A and 12B as follows: A spring loaded cable or lanyard 79 is connected by ring 89 connected to a wedge 80 held in position by a stationary retainer 87 against an opposing wedge 86 which is held stationary by a housing 81. A spring in an expanded, pull position 78 is connected to the first wedge 80 but can not exert any force on the lanyard 79, being prevented from doing so by the opposing wedge 86 held in the cylindrical casing 81 and also in place in a pinned segment 85. The pinned segment 85 is provided with a detonator 84 in the pin position. The low energy detonating cord 55 is connected to and caused to initiate the detonator. For safety purposes, to assure safe separation in case of fuze malfunctioning, the detonator 84 may be a delay detonator, functioning after a time delay to provide that safe separation. The detonator 84 is capable of destroying the pinned segment and thereby permitting wedge 86 to withdraw and release wedge 80 to permit the spring 78 to contract and pull on lanyard 79. As shown in FIG. 11B, this cable or lanyard 79 then pulls the pin 88 out of the spring loaded latch 83 fitting over lip 82 of closure or cover 59 thereby releasing the cover 59 and the "parachute," which are partially ejected and pulled by air pressure into the air stream where the "parachute", i.e. the stabilizer/retarder begins to inflate.
As the "parachute" type of inflatable stabilizer/retarder 58 is pulled by the high velocity air into the air stream the cable or lanyard 69 is pulled tight. It is connected through tubing 72 (FIG. 8) running along the inner wall of the cluster bomb to the nose section, where it is connected to the two pins 103 (FIG. 9) that keep the front end nose section release mechanism from functioning. The cable or lanyard 69 withdraws the two pins 103 (FIG. 9) as the parachute is being pulled out further by the air stream. This causes the nose section 52 of FIG. 8 to be pushed apart by the spring loaded rod 98 (FIG. 9) acting under the pressure of the released compressed spring 100.
As shown in FIG. 10 the 2 nose section 52 of the preferred embodiment B rotate around their open hinges 76, until they separate from the pins 77 and fall past the bomb.
The fuze 51 of FIG. 8 which may stay with one of the 2 segments and is similarly released.
The forward bulk-head 71 of FIG. 8 is no longer supported by the nose section. The "parachute" inflatable stabilizer/retarder 58 begins to fully inflate. Upon full inflation and being connected to the tail section it causes a sufficient sudden deceleration of the bomb so that the contained munition cargo 62 (FIG. 8) overcomes both inertia and the binding and frictional forces of the packing holding it in the cylindrical body 53 and it pushes against the loose front bulkhead, overcoming the air pressure against it and forcing it to give way.
The basic dispersalsystem and advantages thereof is applicable to both of the preferred embodiments. In both cases the bomblet munition pay load as a result of its inertia is forced out of the open nose section into the air stream, where the bomblets are dispersed by it, by being forced to have an angle of attack at an angle to the flight of the cluster bomb. The high pressure incident air, impinging on the tightly packed cluster of bomblets, tilts the same at an angle to the flight of the cluster bomb and this causes the dispersion which is surprisingly, equivalent to that obtained by the more costly, complex and more hazardous dispersion system of prior art. Thus, there is no loss of velocity in the ejection system here. The bomblets retain the velocity of the cluster bomb and use this velocity to obtain an angular dispersion as a result of the impinging air, which drives the tightly packed bomblets apart and forces them to take on a considerable outward angle from the flight direction of the cluster. This causes the dispersion. The dispersion, previously widely used causes a high "drag" or degradation in velocity resulting from air frictional forces. The high drag side dispersion is consequently not an efficient dispersion system in spite of the spin used to obtain dispersion. Where under similar conditions of drop at medium altitudes and speeds a dispersion over an area of 50,000 m 2 was obtained with the prior explosively opened spin activated dispersion systems, the same degree of coverage was obtained with this forward deploying bomblet system. | The design of low cost, safe to use cluster bombs is a prime military objective of aircraft weaponization. Present barriers to cost and safety result from the needed complex dispersion system of the submunition cargo. Spin-up, propulsion of the submunitions, projection of the submunitions and cutting of the walls of the bomb require usually explosives or propellants and always involve complex designs, which are costly to fabricate. The present invention overcomes the deficiencies of the prior art by providing for a novel, simple and inert ejection and adequate dispersion system of the submunition cargo, of multi-purpose, anti-tank, anti-personnel, incendiary bomblets wherein the bomblets are dispersed through the nose end and the aerodynamic forces of the air impinging on the high speed bomblets cause these to fan out and provide for an area coverage which is equivalent to that obtained by the prior more complex and costly dispersal systems. | 5 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to the field of electrical signal processing circuitry, and more particularly to the use of such circuitry for controlling internal combustion engine parameters such as the spark advance in an ignition system.
2. Description of the Prior Art
It has been recognized that the present day mechanical ignition systems for automobiles and similar vehicles cannot meet the requirement for reliably controlling the spark timing, dwell and the proper spark advance of an internal combustion engine over the estimated lifetime of the engine. Generally, most prior art electronic ignition systems utilize a crankshaft position sensor for synchronizing developed electronic control signals to predetermined positions of the engine crankshaft. However, the accuracy of prior art electronic ignition systems is critically dependent upon the duty cycle of the crankshaft position sensor signal. Since the duty cycle of the sensor signal (the ratio of one logic state produced by the sensor to the period of the sensor signal) may vary substantially for various configurations of sensors and under certain extreme engine conditions, most prior art electronic ignition systems have been unable to utilize the sensor signal to accurately control the dwell and spark timing of the engine with the precision which is desired.
One system describes a constant duty cycle monostable multivibrator circuit to produce a simulation of the pulses generated by a conventional point contact ignition system. The time during which the contact points would be held open is made equivalent to the time period of the output pulse generated by the circuit in its unstable state. The ratio of the times for the stable and unstable states or duty cycle of the monostable is a constant although the magnitude of each time individually varies inversely with engine speed.
U.S. Pat. No. 4,170,209, issued Oct. 9, 1979, to Petrie et al. titled "Ignition Dwell Circuit for an Internal Combustion Engine" and assigned to the assignee of the present application shows a circuit especially useful for producing output pulses which occur a fixed time before a predetermined rotational position of an engine's crankshaft. The circuit includes a position sensor triggered dual slope integration circuit producing signals which provides an accurate division of the rotational motion. A clamping circuit generates a corresponding signal having a peak magnitude which corresponds to a first predetermined reference level. A comparator produces a pulse when the clamping signal corresponds to a second reference level which occurs at the fixed time before the rotational position is reached.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide an improved signal processing circuit producing a monostable timing signal adaptable for use with an internal combustion engine.
It is a further object of the present invention to provide an apparatus employing a hysteresis circuit for generating periodic pulse of selectable duration which is independent of the signal period of an input signal derived from a crankshaft position sensor.
In one embodiment of the present invention an improved apparatus for producing monostable type periodic pulses having selectable durations is provided. The apparatus comprises: input sensor means for producing periodic input pulses having leading and trailing edges, wherein the period of said input pulses is variable; bi-stable flip-flop means having set, reset and output terminals, said set terminal coupled to said input sensor means, said flip-flop means producing a first logic state signal at said output terminal in response to each input pulse, said flip-flop capable of producing a second logic state at said output terminal in response to pulses applied to said reset terminal; dual slope rate change means coupled to said bi-stable output terminal for producing a time varying signal having a magnitude varying at a first predetermined slope and direction in response to said first logic state signals and varying at a second predetermined slope with an opposite direction in response to said second logic state signals, said second rate being slower than said first rate; comparator means for comparing the magnitude of said varying signal, while said signal is varying at said first rate, to a predetermined reference level and initiates an output pulse when the magnitude equals said reference levels; hysteresis means coupled between the output of said comparator and said predetermined reference level; and means for coupling said output pulse to said reset terminal, said bi-stable means producing said second logic signal at said output terminal in response to the onset of said output pulse until a subsequent input pulse is received at said set terminal, whereby the duration of said output pulse is controlled by said hysteresis means and is independent of the period of said input pulses.
Essentially, a crankshaft position sensor produces input signal pulses where the period of these pulses is variable and inversely proportional to the speed of engine crankshaft rotation. A flip-flop circuit receives these input pulses at its set terminal and the logic states at its output terminal control a dual slope capacitive integrating circuit such that by charging a capacitor at a first slope and direction in response to one of the flip-flop output logic signals and at a second slope and opposite direction in response to another of the flip-flop output signals, a dual ramp (saw-toothed) waveform is produced. The waveform is coupled to a comparator means that compares the magnitude of the waveform to a reference level and produces an edge of output pulse when the magnitude of the waveform equals the reference level. The comparator means are coupled to the reset terminal of the flip-flop. A hysteresis circuit also connects the output of the comparator back to the reference level whereby the duration of the output pulse is selectable by adjustment of the values of the components in the hysteresis circuit and is independent of the variable period of the input signal pulses. By maintaining the first nd second slopes and directions constant, a precise angular division of the input signal period is performed and the selectable duration output pulse produced can be used to control such engine parameters as the spark timing advance in an electronic ignition system.
BRIEF DESCRIPTION OF THE DRAWINGS
For a more complete understanding of the invention reference should be made to the drawings, in which:
FIG. 1 is a functional block diagram of an apparatus adaptable for use in an ignition system in which periodic output pulses are produced having selectable durations and which are independent of the period of an input signal;
FIG. 2 is a schematic diagram of the electronic circuit diagrammed in FIG. 1.
FIGS. 3A-E are graphs illustrating the relative timing sequence and amplitudes of various signals produced by the circuit shown in FIG. 2.
FIGS. 4A, B are graphs illustrating the timing sequence for the operation of a voltage comparator without hysteresis.
FIGS. 5A, B are graphs of a portion of FIG. 3 enlarged for additional clarity.
FIGS. 6A, B are graphs illustrating the timing sequences shown in FIG. 5 under the condition of very rapid engine acceleration.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to FIG. 1, an apparatus for the generation of monostable pulses having durations which are independent of the input signal period is shown. A periodic input signal from sensor 10 is coupled to an input of a flip-flop circuit 12 which has an output coupled to a dual slope integrating means 14. The dual slope integrating means (shown enclosed in a broken line) is further comprised of a discharging slope means 16, which receives an output signal from flip-flop 12 and charging slope means 18. Both signal means are connected to an integrator 20 whose output is coupled to a first input of a comparison means 22. Comparison means 22 also receives at a second input, a voltage signal from reference voltage source 24. The output signal from comparison means 22 is coupled to hysteresis control circuit 26 and to flip-flop 12. Hysteresis control circuit 26 is connected to reference signal source 24 and operates to change the reference voltage input to comparison means 22 at a predetermined time. The output of comparison means 22 is a monostable pulse having a duration which is independent of the period of the input sensor signal.
The hysteresis control circuit operates to change the voltage at the reference input of comparison means 22 immediately after the comparison means 22 has changed its state in response to the initial condition of voltage equality. Hysteresis in this sense means a form of non-linearity in the response of the circuit to a particular set of input conditions which depend not only on the instantaneous values of those conditions, but also on the immediate past of the input and output signals. It is the interconnection of the hysteresis circuit with the comparison means 22 which establishes at the output of comparison means 22 the fixed duration monostable pulses. As will be more particularly described later, a fixed width time pulse can be generated at a period corresponding to the engine rotation period detected by sensor 10. Modifications in the hysteresis control circuit can alter the pulse width of the monostable output pulses. Thus, within certain design limitations which relate to the design criteria of the engine and the speed range over which it operates, a selectable range of pulse widths may be established to control engine parameters. In particular the pulses may be used to advance or retard the spark timing by a fixed amount. It will be understood by those skilled in the art that additional spark timing modification may be achieved in an incremental manner.
FIG. 2 is a schematic for the circuit block diagrammed in FIG. 1 and illustrates the apparatus which receives periodic input signals producing periodic monostable output pulses that have durations independent of the input signal period. The apparatus basically comprises an input sensor 10, a D-type flip-flop circuit 12 connected as an R-S flip-flop, a dual slope integrating circuit 14 again shown enclosed with a broken line and a voltage comparator 30.
Preferably, the apparatus is intended for use in the ignition system of an internal combustion engine and the sensor 11 corresponds to a crankshaft position sensor for producing periodic input pulses having leading and trailing edges at an output terminal A. The period of these input pulses is variable and related (inversely proportional) to the rotational speed of the crankshaft of the engine since the occurrence of these pulses is determined by predetermined rotational positions of the engine crankshaft (not shown). The sensor 10 can be either a magnetic sensor or, preferably, a Hall effect sensor.
The terminal A of the sensor 10 is directly coupled to a set terminal S' of the flip-flop 12. Data and clock terminals (D' and C', respectively) of the flip-flop are both directly connected to ground potential and a flip-flop output terminal Q is directly connected to an output terminal B while an additional flip-flop output terminal Q is directly connected to a terminal C, which is the input terminal of the dual slope integrating circuit 14. A terminal D is the output terminal of the dual slope circuit 14 and is directly connected as an input to an inverting input terminal of a comparator 30. A non-inverting input terminal of the comparator 14 is connected to ground through a resistor 32 and is also connected to a positive voltage supply terminal 34 through a resistor 36. A terminal E represents the output terminal of the comparator 30 and is coupled to the positive voltage supply terminal 34 through a resistor 38. Terminal E is directly connected by a conductor 40 to a reset terminal R' of the flip-flop 12.
The output terminal of comparator 30 is also connected to its own non-inverting input terminal through a resistor 42. It is this circuit interconnection which provides the hysteresis effect and determines the fixed pulse width for output pulses from comparator 30. It may be appreciated that the value of resistor 42 in the hysteresis circuit can be changed in conjunction with the reference voltage source to produce a different pulse width.
The dual slope integrating circuit 14 shown in FIG. 2 comprises a resistor 44 coupled between the terminal C and the base of an NPN transistor 46 which is also connected to ground through a resistor 48. The emitter of the transistor 46 is connected to ground and the collector is directly connected to both the base and collector electrodes of an NPN transistor 50 which has its emitter directly connected to ground. The collector of transistor 50 is connected to the voltage supply terminal 34 through a resistor 52 and is directly connected to the base of an NPN transistor 54. Transistor 54 has its emitter directly connected to ground and its collector directly to the output terminal D. An integrating capacitor 56 is coupled between the terminal D and ground. A PNP transistor 58 has its collector electrode directly connected to the terminal D and its emitter electrode connected to the terminal 34. The base of the transistor 58 is connected to ground through a resistor 60 and is directly connected to the base and collector electrodes of a PNP transistor 62, which has its emitter directly connected to the terminal 34. The components 44-62 comprise the dual slope integrating circuit 14 shown in FIG. 2.
The operation of the circuit shown in FIG. 2 will now be described with reference to the signal waveforms illustrated in FIGS. 3A through 3E which directly correspond to the signal waveforms produced at the terminals A-E in FIG. 2, respectively. The waveforms in FIGS. 3A-E represent voltage waveforms for which the vertical axis represents amplitude and the horizontal axis represents time. A breakpoint 64 is shown in the time axis of these waveforms and the waveforms to the right of the breakpoint represent those signals produced at an engine crankshaft speed which is approximately twice the engine crankshaft speed that produced the waveforms to the left of the breakpoint. In all of the drawings, identical reference numbers and letters are used to identify identical components, terminals, signals and reference voltage levels.
As previously mentioned, the crankshaft position sensor 10 produces a sensor signal designated generally by the reference number 70 and shown in FIG. 3A. This signal 70 comprises a plurality of variable period input signal pulses 72 wherein each pulse occurs at a predetermined rotational position of the engine crankshaft. Each pulse has a leading edge 74 and a trailing edge 76. FIG. 3A illustrates that the pulses produced to the left of the breakpoint 64 occur at a period T. This period is variable and is inversely proportional to the rotational speed of the engine crankshaft. To the right of the breakpoint 64, the signal 70 is illustrated as having a period T' which represents a higher engine crankshaft rotational speed, approximately twice the rotational speed that created the signal 70 to the left of the breakpoint 64. While FIGS. 3A-E illustrate signals with constant periods to the right and left of the breakpoint 64, it should be noted that the input signal period is related to the engine crankshaft speed and therefore is contemplated as being variable. FIGS. 3A-E are merely shown with two different constant periods to clarify the explanation of the operation of the present invention.
In FIG. 3A each sensor pulse 72 is illustrated as occurring at a time t o , and the time from one t o to the next represents the period T of the signal 70. The pulses 72 are received at the set terminal S' of the bi-stable flip-flop circuit 12. FIGS. 3B and 3C illustrate the outputs of the flip-flop circuit 12 at the output terminals Q and Q, repsectively, as well as the signals created at the terminals B and C, respectively. The signal produced at terminal B is designated by the reference number 78 whereas the signal produced at the terminal C is designated by the reference numberal 80. Each signal comprises first and second logic states and the logic states of signal 78 are the inverse of the logic states of signal 80.
In response to each sensor pulse 72 received at the set terminal S', the flip-flop circuit 12 creates a low logic signal 82 at the terminal C. Subsequently for the preferred embodiment, after precisely one-third of the period T has elapsed, the signal 82 will be switched to a second or high logic state 84 and the signal 80 will retain this second logic state until the next input sensor pulse 72. The manner by which the signal 80 is caused to switch logic states after the elapsing of precisely one-third of the period T will now be discussed.
FIG. 3D illustrates a dual ramp signal 86 representing the voltage at the terminal D which is the voltage maintained at one terminal of the capacitor 56. Initially, at the time t o the voltage 86 is assumed to be at an initial value V i . In response to the low logic state 82 produced at the terminal C, with the low logic state corresponding to ground potential, the transistor 46 is turned off. This results in turning on the transistor 50 and having the transistor 54 discharge the capacitor 56 at a constant predetermined rate. This constant discharging rate is illustrated in FIG. 3D by the straight line segment having negative slope k 1 and this rate of discharge is determined by the current passing through the resistor 52, minus any charging current supplied by the transistor 58. The transistor 50 is essentially connected as a diode and the current through the resistor 52 determines the voltage developed by the diode connected transistor 50. Since transistor 54 has its base-emitter junction biased by the voltage developed by the diode connected transistor 50, the transistor 54 will also conduct precisely the same current that is being drawn through the resistor 52. Thus the combination of the components 50 through 54 represents a constant current source that results in discharging the capacitor 56 at a predetermined rate k 1 which results in decreasing the voltage across the capacitor, corresponding to the signal 86, at the same rate.
The voltage at the terminal D is monitored by the comparator 30 which compares this voltage to a predetermined reference level voltage initially determined by the resistor divider network comprising the resistors 32 and 36 since the output of comparator 30 is at a low logic level. This first reference level voltage corresponds to the voltage at the junction between the resistors 32 and 36 and is illustrated in FIG. 3D by the broken reference line 88.
The output of the comparator 30 at the terminal E remains constant at a low level until the capacitor voltage signal 86 at the terminal D is decreased enough so that its magnitude equals the initial reference level voltage 88. When this occurs, the comparator 30 produces a pulse signal 90 as shown in FIG. 3E. As shown, the equality condition occurs at a time t 1 after the time t o . The duration of this pulse 90 is controlled by the presence of the hysteresis circuit and will be explained in greater detail later. It may be observed in FIG. 3D that when signal 86 reaches a second voltage reference level 89 the pulse 90 is terminated. The pulse 90 is supplied to the reset terminal R' of the flip-flop 12 by a conductor 40. The leading edge 92 of the pulse 90 causes switching of the logic state of the signal 80 at the terminal C to the second logic state 84.
With signal 80 having a magnitude corresponding to the second logic state or high voltage logic state 84, transistor 46 is turned on. When transistor 46 is turned on, the transistors 50 and 54 are turned off thereby preventing the discharge of the capacitor 56 by means of the current drawn by the transistor 54.
Whenever the transistor 54 is not discharging the capacitor 56, the transistors 58 and 62 will charge up the capacitor at a constant predetermined rate k 2 (smaller magnitude than the rate k 1 ) determined by the magnitude of the resistor 60. The components 58-62 represents a constant current source which functions identically to the constant current source created by the components 50-54. The signal 86, corresponding to the voltage at terminal D, is increased at a constant rate determined by the magnitude of the resistor 60. This constant rate of increase is illustrated in FIG. 3D by a straight line segment having a positive slope k 2 , whereas the slope k 1 had a negative slope. The magnitude of the signal 88 continues to increase until a crankshaft position pulse 72 is again received at the set terminal S' of the flip-flop 12, which results in recommencing the entire previously described cycle.
As will be described more fully later, since the magnitude of the voltage at the terminal D is increasing at the rate k 2 at time t 1 , this would normally result in terminating the pulse 90 produced by the comparator 30 resulting in a spike. But the presence of the hysteresis circuit prevents the termination under these conditions and pulse 90 is characterized by a leading edge 92, a trailing edge 93 and having a low logic level 94 and a high logic level 95. The hysteresis circuit functions to maintain the high logic level output for comparator 30 for a predetermined time after which the output returns to the low logic level 94. The pulse 90 termination is determined by equality between signal 86 and the second voltage reference level 89. This is shown in FIG. 3E which also shows that although T' on the right side of break line 64 is much less than T and the corresponding sensor and voltage signals are contracted on the right hand side of break line 64, the pulse width T for pulse 90 remains invariant.
For the magnitude of slope k 1 , equal to 2 times the magnitude of slope k 2 which is the case for the preferred embodiment the time division of the input sensor signal is 1:2. An additional description of the circuit operation and a full discussion of the design parameters for the dual slope integrating circuit without a hysteresis circuit may be found in the above-mentioned U.S. Pat. No. 4,170,209 which is hereby incorporated by reference.
Although voltage comparators are well known in the art, it is advantageous to describe the operation so that the function of the comparator with the hysteresis circuit can be better understood. FIG. 4A illustrates the voltage levels at the inputs to a comparator, identical to comparator 30 but with the hysteresis circuit comprising resistor 42 removed, and FIG. 4B illustrates the corresponding logic levels at the comparator output. Ramp voltage signals 100 and 102 are serially applied to the inverting input terminal of the comparator. A reference voltage 104 is applied to the non-inverting input terminal of the comparator. FIG. 4B shows the output of the comparator as a square wave pulse having a low logic level 106 and a high logic level 108. The leading edge 110 of the square wave pulse occurs at a time when ramp voltage 100 is equal to the reference voltage 104. At this instant the comparator changes state producing leading edge 110. The voltage level at the negative input voltage to the comparator has now become less than the reference voltage 104 and as long as this condition exists the comparator is inhibited from further changes of state. At the same time subsequent to the change to a high logic state, ramp signal 102 increases the voltage level applied at the negative input of the comparator to again equal the reference voltage 104. At equality, the comparator changes state to the low logic level 106 and produces the trailing edge 112 of the square wave pulse. The state of the comparator output is seen to depend upon the relative magnitudes of the voltages at the input terminals and changes of state occur only at equality.
It is the interconnection of resistor 42 in combination with resistors 32, 36 and 38 which constitute the hysteresis circuit in the preferred embodiment. Comparator 30 compares two along voltages, one from capacitor 56 and the other a reference, and develops logic output signals distinguishing the variable input voltage as being greater or less than the reference level. The transition between the logic levels occurs at the instant of equality at the input terminals of comparator 30. As those skilled in the art will appreciate variation of the values of resistors 32, 36, 38 and 42 will produce a range of output pulse durations.
In operation, as the voltage 86 at terminal D of capacitor 56 decreases to an initial reference level 88, comparator 30 remains in a low logic level designated as 94 in FIG. 3E. For increased clarity FIGS. 5A, B show corresponding portions of FIGS. 3D and 3E on an enlarged scale. At time t 1 when the voltage at terminal D equals the initial reference voltage level 88 now designated as V REF1 in FIG. 5A, the comparator 30 changes its logic state from 94 to 95 to produce the leading edge 92 of pulse 90. However, due to the hysteresis circuit, at substantially the same time t 1 , the original reference voltage level V REF1 has been changed to a voltage level 89 now designated as V REF2 . Since the voltage at terminal D is now less than the new reference level, comparator 30 maintains the high logic level 95 as shown in FIG. 5B. No change of state can occur in comparator 30 until the voltage at terminal D is increased to equal the value of the new reference level V REF2 . This occurs at time t 2 at which time the output of comparator 30 returns to its low logic level 94. And, at substantially the same time, the voltage reference level returns to V REF1 . It may be observed that the reference voltage level changes are always in the direction of anticipated changes in the voltage at terminal D to prevent any uncertainty caused by a multi-valued functional relationship in the voltage vs time plots. As before, the time interval Δt=t 2 -t 1 does not vary from pulse to pulse.
FIGS. 6A, B show graphs similar to FIGS. 5A, B but under the conditions of very rapid engine acceleration. As may be seen the intervals between pulses 90 is rapidly diminishing but the pulse width Δt is again invariant. Thus, as may be seen in FIGS. 6A, B, a fixed duration time pulse has been derived which is independent of the period of the incoming sensor pulse signal.
As will be appreciated by those skilled in the art, one or more additional comparators may be coupled to capacitor 56 and to an independent reference voltage source for the purpose of initiating a pulse which has a leading edge at any time before or after the initiation of the pulse by comparator 30. A more likely choice is to initiate the new pulse before the equality in comparator 30. This additional pulse may be combined with the output pulse from comparator 30 in a logic circuit to generate a fixed duration time pulse beginning at any time within the period of the sensor signal. The combined pulse would again have a selectable duration and be invariant within the normal design limitations of the engine and its operational range.
While a specific embodiment of this invention has been shown and described, further modifications and improvements will occur to those skilled in the art. All modifications which retain the basic underlying principles disclosed and claimed herein are within the scope of this invention. | Electronic signal processing circuitry particularly useful in the ignition system of an internal combustion engine is disclosed. A pulse generator includes a crank-shaft position sensor supplying periodic position pulses to a bi-stable flip-flop circuit controlling a dual slope integration circuit. The integration circuit establishes a dual ramp time varying voltage signal at one input to a comparator for comparison with a reference voltage source which is established at the second input. At equality, an output pulse is initiated at the output of the comparator and this pulse is also used to change the logic state of the flip-flop. A hysteresis circuit responds to the initiation of the output pulse by modifying by a predetermined amount, the reference voltage level at the comparator. The duration of the output pulse is thereby made selectable and independent of variations in the period of the sensor pulses. | 8 |
CROSS REFERENCE TO RELATED APPLICATION
The application claims priority to U.S. Provisional Application No. 60/937,413 which was filed on Jun. 27, 2007.
BACKGROUND OF THE INVENTION
This disclosure generally relates to a speaker assembly mounted within a vehicle instrument panel for generating warning and alert tones. More particularly, this disclosure relates to a speaker assembly that is substantially resistant to water and that is installed on the face of a vehicle instrument panel.
Instrument panels in motor vehicles are required to be substantially water proof to prevent potential damage caused by any number of events that could result in liquid penetrating to the electrical devices and connections within the instrument panel. Because of the requirement to be waterproof, speakers are not included on an exposed face of the instrument panel, but are instead mounted deep within the instrument panel and under the dashboard. Such a location presents several disadvantages. In some instances the location of the speaker will mute or muffle the warning and alert noises such that the operator may not hear them. To overcome this problem, a larger and more powerful speaker may be required, at a corresponding increase in cost and space utilized.
Accordingly, it is desirable to develop a speaker for use within a vehicle instrument panel that can be mounted in a location favorable for directing alert sounds to a vehicle operator.
SUMMARY OF THE INVENTION
An example speaker for a vehicle instrument panel includes a membrane for preventing water from intruding into the speaker assembly and instrument panel. The membrane is spaced apart from the speaker and over an open end of a speaker housing. Sound energy from the speaker travels through an open space against a back side of the membrane. The membrane possesses acoustic properties to receive and pass on the sound energy. Because the example speaker assembly is water proof, it can be directed outward on the visible and exposed face of the instrument panel. Because nothing is obstructing sounds emanating form the speaker assembly, the sound quality can be improved along with increasing volumes to aid in alerting and warning a vehicle operator.
These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front view of an example instrument panel.
FIG. 2 is a schematic side view of an example speaker assembly.
FIG. 3 is an exploded view of the example speaker assembly.
FIG. 4 is a block diagram of the example speaker assembly.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1 , a vehicle dashboard 11 includes an instrument panel 10 with speaker assemblies 12 . The speaker assemblies 12 emit sounds generated to alert a vehicle operator of specific vehicle conditions, such as for example a door open, keys left in the ignition or a warning when a fuel level goes low. The sounds generated are noises such as beeps, chimes or other tones familiar to a vehicle operator to warn and inform of current vehicle condition. The instrument panel 10 is required by vehicle manufacturers to be water proof. The example speaker assemblies 12 are pointed outward from the instrument panel 10 to improve the communication of sounds to an operator.
Referring to FIGS. 2 and 3 , the example assembly 12 includes a speaker 22 mounted to a printed circuit board (PCP) 18 . The speaker 22 and circuit board 18 are mounted within a housing 16 . The example housing 16 is cylindrical and includes an open front end 48 . The open front end 48 faces outward from the instrument panel 10 similar to how a dial gauge is positioned and visible in the instrument panel 10 . Connectors 20 provide electrical communication between the PCP 18 and a circuit ( FIG. 4 ) powering the speaker 24 . The connectors 20 are as known in the art.
A membrane 24 extends over the open end 48 over the speaker 22 . The membrane 24 is spaced apart from the speaker 22 such that an open space is provided between the speaker 22 and the membrane 24 . The membrane 24 is held in place across the open end by a guide ring 26 and bezel 28 . The bezel 28 may provide for securing the membrane 24 in place along with the guide 26 or may simply provide a desired cosmetic appearance providing a desired look to the instrument panel 10 .
The membrane 24 is fabricated from a material that prevents water from penetrating through to the housing 16 . The specific material can be any material that provides a water resistant or water proof function. The membrane 24 also includes desired acoustic properties such that it is reactive to sound energy. The membrane 24 receives sound energy generated by the speaker 24 and communicates and amplifies that sound energy to project the desired sounds outward from the panel 10 toward an occupant of the vehicle.
The membrane 24 provides the function of preventing water from entering the speaker assembly 12 , while also performing the function of a speaker cone to further amplify and communicate sound energy from the instrument panel 10 . Sound energy generated by the speaker 22 is communicated to a back side of the membrane 24 . The membrane 24 vibrates in response to the sound energy from the speaker 24 and communicates that sound energy outward. The sound energy is amplified due to the larger area of the membrane as compared to the speaker 22 .
Referring to FIG. 4 , the speaker assembly 22 includes an amplifier 30 powered by a power supply 34 and controlled by a microcontroller 32 . The power supply includes a positive lead 40 and a ground 42 that is connected to a vehicle power supply. A communication link 38 provides signal indicative of vehicle conditions to a communication hub 36 and further from the communication hub 36 to the microcontroller 32 . The microcontroller 32 actuates the amplifier to generate signals utilized by the speaker 30 to generate sound energy and specified frequencies and volumes to produce the desired tones.
The speaker 22 generates sound energy matched to the membrane 24 to produce the desired tone, chime or beep. The speaker 22 and membrane 24 act in concert within the housing 16 to produce the final audible tones. The housing 16 , speaker 22 and membrane 24 all factor into the end sound produced by the speaker assembly 12 .
Besides projecting sound energy from the speaker 22 , the membrane 24 protects and prevents water intrusion. This feature provides for the speaker assembly 12 to meet water proofing requirements of the instrument panel 10 . Because the example speaker assembly 12 is water proof, it can be directed outward on the visible and exposed face of the instrument panel. Additionally, it may be possible to utilize a smaller, less powerful speaker 22 as compared to prior art speakers that were required to be installed deep within the instrument panel and still provide an equal volume. Further, because nothing is obstructing sounds emanating form the speaker assembly, the sound quality can be improved along with increasing volumes to aid in alerting and warning a vehicle operator.
Although a preferred embodiment of this invention has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention. | An example vehicle instrument panel includes a speaker for producing alert and warning sounds. A membrane prevents water from intruding into the speaker assembly and instrument panel. The membrane is spaced apart from the speaker and over an open end of the speaker housing. Sound energy from the speaker travels through an open space against the membrane. The membrane possesses acoustic properties to receive and pass on the sound energy. | 1 |
This is a Continuation-in-Part of Application Ser. No. 07/255,699, filed on Oct. 11, 1988 now issued as U.S. Pat. No. 4,967,818.
BACKGROUND OF THE INVENTION
White sidewall tires are very popular in the United States and Canada. Tires having other types of appliques on the sidewalls thereof, such as lettering, logos, and the like, are also very popular. However, the construction of tires having white sidewalls or decorative appliques on the sidewall thereof is a complicated procedure. It involves the coextrusion of a black sidewall rubber with a white sidewall rubber and laminating a protective cover strip over the white rubber to form a sidewall preassembly. This tire sidewall preassembly is then applied in sequence with the other required tire components to the tire building drum to form a green or uncured tire. The green tire is then typically cured in a tire press, with the desired applique being formed by the grooves in the tire mold. After the tire has been cured, it is carefully ground and buffed to expose the decorative applique which was previously covered and protected by the cover strip.
Coextrusion is a complicated process which involves the utilization of sophisticated equipment and a large number of profile dies. The grinding and buffing step which is required to remove the cover strip is also complicated and labor intensive. These additional steps which are required in building tires having decorative appliques on a sidewall thereof add significantly to the cost of building the tire.
In conventional white sidewall tires, the white rubber component represents a very substantial portion of the sidewall. However, it is desirable for tires to have thin sidewalls in order to attain desired performance characteristics. Accordingly, the decorative applique on the sidewall of a tire should be as thin as possible. Nevertheless, certain production and performance criteria has limited the degree to which the thickness of sidewall applique can be reduced.
There are additional problems associated with tires having decorative applique on a sidewall thereof which are built using standard techniques. For instance, such tires have more blemishes, imperfections, and voids in the sidewall area as compared to black sidewall tires. Additionally, problems associated with the white sidewall splice opening sometimes also occur. Misalignment of the white sidewall preassembly relative to mold grooves is a frequently encountered problem which leads to blemished tires. The grinding procedure used in building standard tires having decorative appliques on a sidewall thereof some times leads to the formation of surface crack sites.
For the aforementioned reasons, tires having decorative appliques on a sidewall thereof and the conventional procedures used in building such tires leave much to be desired. To obviate these shortcomings associated with standard techniques for building tires having decorative appliques on a sidewall thereof, it has been proposed to replace the previously known sidewall decorative features with appliques which are painted on to conventional black wall tires. However, painting designs on to the sidewall of tires has not proven to be a satisfactory answer to the problem. This is largely due to the fact that designs which are painted on are quite thin and can be easily damaged by scraping, scuffing and the like.
The concept of applying premolded tire sidewall appliques to standard black wall tires has also been proposed. For example, such a procedure is described in European Patent Application Publication No. 249,918. However, such procedures have not proven to be entirely satisfactory. For instance, difficulties have been encountered with maintaining adequate adhesion between the sidewall applique and the tire. More specifically, tires made utilizing such techniques typically have inferior scuff resistance such that the applique fails at the interface.
SUMMARY OF THE INVENTION
By practicing the technique of this invention, uncured tire sidewall appliques can be successfully applied to standard uncured black wall tires. These appliques can be affixed to uncured tires prior to putting them in the curing mold or the appliques can be placed in a specific location in the curing mold, such as a white sidewall groove, prior to putting the uncured tire in the curing mold. This technique involves utilizing decorative appliques which are comprised of from about 25 weight percent to about 75 weight percent syndiotactic 1,2-polybutadiene and from about 25 weight percent to about 75 weight percent of at least one polydiene rubber. In the method of this invention, the decorative design is simply applied to the sidewall of a standard uncured black wall tire with the tire being subsequently cured so as to permanently affix the decorative design or applique to the sidewall thereof.
This invention specifically discloses a method of preparing a pneumatic rubber tire having a decorative applique on the sidewall thereof which comprises (a) applying the decorative applique to the sidewall of an uncured tire; wherein the decorative applique has a thickness which is within the range of about 10 mils to about 125 mils; and (b) curing the tire; wherein the decorative design is comprised of from about 25 weight percent to about 75 weight percent syndiotactic 1,2-polybutadiene having a melting point which is within the range of about 70° C. to about 160° C. and from about 25 weight percent to about 75 weight percent of at least one polydiene rubber which is cocurable with said syndiotactic 1,2-polybutadiene, sulfur, zinc oxide, and at least one pigment or colorant.
The subject invention also reveals a pneumatic tire having a decorative applique on the sidewall thereof, comprising an outer circumferential tread, a supporting carcass therefor, two-spaced beads and two rubber sidewalls connecting said beads; wherein at least one of said sidewalls has a decorative applique thereon; wherein the decorative applique has a thickness which is within the range of about 10 mils to about 125 mils; and wherein said decorative applique is comprised of from about 25 weight percent to about 75 weight percent syndiotactic 1,2-polybutadiene having a melting point which is within the range of about 70° C. to about 160° C. and from about 25 weight percent to about 75 weight percent of at least one polydiene rubber which is cocured with said syndiotactic 1,2-polybutadiene, and at least one pigment or colorant.
DETAILED DESCRIPTION OF THE INVENTION
Standard uncured black wall tires are utilized in manufacturing the tires of this invention which have a decorative applique on a sidewall thereof. The uncured black wall tire which is utilized is built utilizing conventional procedures which are well known to persons skilled in the art of building black wall tires. In accordance with this invention, the decorative applique is affixed as desired to the sidewall of the green black wall tire. The tire is then cured in a mold utilizing standard curing procedures. The decorative applique can be applied to the sidewall of the uncured tire before it is put in the curing mold. However, it is normally advantageous to position the decorative applique in the tire mold prior to putting the uncured tire therein. In either case, during the curing process the decorative applique becomes securely bound to the tire sidewall. It is believed that the syndiotactic 1,2-polybutadiene (SPBD) and the diene rubbers in the decorative applique cocured with the rubbers in the sidewall of the uncured tire. It is, accordingly, believed that the decorative applique becomes cocured to the standard tire sidewall.
The syndiotactic 1,2-polybutadiene used in the practice of the subject invention normally has more than 65% of its monomeric units in a syndiotactic 1,2-configuration. SPBD can be prepared in an inert organic solvent utilizing the technique described in U.S. Pat. No. 3,901,868 or in an aqueous medium utilizing the process described in U.S. Pat. No. 4,506,031. U.S. Pat. No. 4,506,031 more specifically reveals a process for producing polybutadiene composed essentially of SPBD comprising the steps of:
(A) preparing a catalyst component solution by dissolving, in an inert organic solvent containing 1,3-butadiene (a) at least one cobalt compound selected from the group consisting of (i) β-diketone complexes of cobalt, (ii) β-keto acid ester complexes of cobalt, (iii) cobalt salts of organic carboxylic acids having 6 to 15 carbon atoms, and (iv) complexes of halogenated cobalt compounds of the formula CoX n , wherein X represents a halogen atom and n represents 2 or 3, with an organic compound selected from the group consisting of tertiary amine alcohols, tertiary phosphines, ketones, and N,N-dialkylamides, and (b) at least one organoaluminum compound of the formula AlR 3 , wherein R represents a hydrocarbon radical of 1 to 6 carbon atoms;
(B) preparing a reaction mixture by mixing said catalyst component solution with a 1,3-butadiene/water mixture containing desired amounts of said 1,3-butadiene;
(C) preparing a polymerization mixture by mixing carbon disulfide throughout said reaction mixture, and
(D) polymerizing said 1,3-butadiene in said polymerization mixture into polybutadiene while agitating said polymerization mixture. In the process described therein the crystallinity and melting point of the SPBD can be controlled by adding alcohols, ketones, nitriles, aldehydes or amides to the polymerization mixture.
The SPBD utilized in making the decorative appliques for tires has a melting point of about 160° C. or less. The SPBD will normally have a melting point within the range of about 70° C. to about 160° C. It is generally preferred for the SPBD utilized in making decorative white sidewalls for passenger car or truck tires to have a melting point which is within the range of about 80° C. to about 150° C. with a melting point which is within the range of 90° C. to 125° C. being most preferred. The melting points referred to herein are the minimum endotherm values determined from DSC (differential scanning calorimetry) curves.
The compositions utilized in making the decorative appliques of this invention is a blend which is comprised of SPBD and at least one rubber which is cocurable with the SPBD. The rubber used in such blends can be virtually any type of elastomer which contains unsaturation that allows for sulfur curing. Typically, the elastomer will be one or more polydiene rubbers. Some representative examples of suitable polydiene rubbers include cis-1,4-polybutadiene, natural rubber, synthetic polyisoprene, styrene butadiene rubber, EPDM (ethylene-propylene-diene monomer) rubbers, isoprene-butadiene rubbers, and styrene-isoprene-butadiene rubbers. In many cases it will be desirable to utilize a combination of diene rubbers in the blend. For instance, the rubber portion of the blend can be a combination of chlorobutyl rubber, natural rubber, and EPDM rubber. It is particularly preferred to utilize a combination which contains from about 30 weight percent to about 80 weight percent chlorobutyl rubber, from about 15 weight percent to about 55 weight percent natural rubber, and from about 2 weight percent to about 10 weight percent EPDM rubber as the rubber component in such blends. A rubber composition which contains from about 55 weight percent to about 65 weight percent chlorobutyl rubber, from about 25 weight percent to about 45 weight percent natural rubber, and from about 3 weight percent to about 7 weight percent EPDM rubber is more highly preferred.
The blend utilized in preparing the decorative applique will normally contain from about 25 weight percent to about 75 weight percent SPBD and from about 75 weight percent to about 25 weight percent elastomers which are cocurable with the SPBD. The inclusion of high levels of SPBD results in better adhesion, abrasion, and tear resistance for the cured material. High levels of SPBD also result in increased green strength and stiffness. Additionally, the use of high levels of SPBD reduces green tack which makes handling easier and allows for stacking without the use of a substrate. However, the incorporation of large amounts of SPBD into the blend also results in reduced flexibility and modulus. Accordingly, for the best balance of overall properties, the blend utilized will contain from about 33 weight percent to about 67 weight percent SPBD and from about 67 weight percent to about 33 weight percent cocurable rubbers. The blends which are most highly preferred will contain from about 45 weight percent to about 55 weight percent SPBD and from about 55 weight percent to about 45 weight percent of the elastomeric component.
The SPBD used in making the blends from which the appliques are formed is generally incorporated into the blend in powder or pellet form. In other words, the SPBD is in the form of a powder or pellet at the time it is compounded with the rubber component utilized in making the blend of which the decorative applique is comprised. The SPBD utilized in accordance with this invention can be reduced to powder form by grinding or another appropriate technique.
The SPBD powder or pellets can be mixed into the rubber component utilizing standard mixing techniques. However, the mixing is normally carried out at a temperature which is at least as high as the melting point of the SPBD being utilized. During the mixing procedure, the SPBD powder pellets are fluxed into the rubber with additional desired compounding ingredients. Such mixing is typically carried out in a Banbury mixer, a mill mixer or in some other suitable type of mixing device.
In an alternative embodiment of this invention, the blend utilized in preparing the decorative applique is prepared by inverse phase polymerization. For example, a blend of SPBD with cis-1,4-polybutadiene can be prepared in an organic solvent by inverse phase polymerization. In such a procedure, the cis-1,4-polybutadiene is first synthesized in an organic solvent under solution polymerization conditions. This polymerization can be catalyzed by using a variety of catalyst systems. For instance, a three component nickel catalyst system which is comprised of an organoaluminum compound, a soluble nickel containing compound and a fluorine containing compound can be utilized to catalyze the polymerization. Such a polymerization can also be catalyzed by utilizing rare earth catalyst systems, such as lanthanide systems, which are normally considered to be "pseudo-living". Such rare earth catalyst systems are normally comprised of three components which include (1) an organoaluminum compound, (2) an organometallic compound which contains a metal from Group III-B of the Periodic System, and (3) at least one compound which contains at least one labile halide ion. Metals from Group I and II of the Periodic System can also be utilized as catalysts for polymerizing 1,3-butadiene monomer into cis-1,4-polybutadiene. The metals which are most commonly utilized in such initiator systems include barium, lithium, magnesium, sodium and potassium with lithium and magnesium being the most commonly utilized. The cis-1,4-polybutadiene cement which is synthesized is then subsequently utilized as the polymerization medium for the synthesis of the SPBD. It will generally be desirable to add additional 1,3-butadiene monomer to the cis-1,4-polybutadiene cement for the synthesis of the SPBD. In some cases, it will also be desirable to add additional solvent. The amount of monomer added will be contingent upon the proportion of SPBD desired in the blend being prepared. It will, of course, also be necessary to add a catalyst system to the rubber cement which is capable of promoting a polymerization which results in the formation of SPBD. A detailed description of such catalyst systems is given in U.S. Pat. No. 3,778,424 which is herein incorporated by reference in its entirety.
The blend of SPBD and rubber will also contain other standard rubber chemicals. For instance, such blends will additionally contain sulfur and at least one desired colorant or pigment. They will also typically contain other rubber chemicals, such as antioxidants, accelerators, oils, and waxes in conventional amounts. For instance, the SPBD/rubber blend will normally contain from about 0.2 to about 8 phr of sulfur. It is generally preferred for the blend to contain from about 0.5 to 4 phr of sulfur with it being most preferred for such blends to contain from 1 to 2.5 phr of sulfur. A primary accelerator is generally also present at a concentration which is within the range of about 0.1 to about 2.5 phr. It is normally preferred for the primary accelerator to be present at a concentration which is within the range of about 0.2 to about 1.5 phr with it being most preferred for the primary accelerator to be at a concentration of 0.3 to 1 phr. Secondary accelerators will also commonly be utilized at a concentration which is within the range of about 0.02 to about 0.8 phr. Secondary accelerators are preferably utilized at a concentration of 0.05 to 0.5 phr with the utilization of 0.1 to 0.3 phr of a secondary accelerator being most preferred. Such SPBD/rubber blends will typically contain from about 1 to about 10 phr of various processing oils and it is generally preferred for such blends to contain from about 2.5 to about 7.5 phr of processing oils. The SPBD/rubber blend will generally contain from about 25 phr to about 100 phr of various fillers such as clay and/or titanium dioxide. It is normally preferred for such blends to contain from about 40 phr to about 80 phr fillers. It should be noted that titanium dioxide acts as both a filler and a white pigment. Some representative examples of colorants that can be utilized in the SPBD/rubber blend to impart desired colors to the decorative appliques include diarylid yellow 17, pththalocy blue 15, diarylid orange 13, and perm red 2B (red 48:1).
After the SPBD/rubber blend has been compounded as desired, it is processed into the desired decorative applique. This can be accomplished by milling and calendering the compounded blend into a continuous sheet and subsequently cutting an applique having the desired shape out of the sheet. Sheets of the compounded SPBD/rubber blend can also be made by continuous cold feed extrusion, such as with twin screw equipment or single screw extruders with mixing sections. Decorative appliques in the form of strips, rings, logos, letters, or numbers can also be prepared by injection molding or transfer molding.
The decorative appliques utilized in the process of this invention that are obtained from calendered film will normally have a thickness which ranges from about 10 mils to about 80 mils (0.010 to 0.080 inch). However, appliques having a thickness within the range of about 15 mils to about 50 mils will normally be utilized to save material. This is because satisfactory performance can normally be obtained without the need for utilizing thicker decorative appliques. Letters, numbers, and logos which are made by calendering will normally have a thickness of about 30 mils to about 50 mils. On the other hand, decorative appliques having a thickness of less than about 40 mils are generally difficult to injection mold. For this reason, appliques which are injection molded will normally have a thickness of at least about 60 mils. There are generally no problems in calendering sheets of the SPBD/rubber component blends which have thicknesses of less than 30 mils. For this reason, thin appliques will normally be calendered into sheets with the desired design being cut therefrom. White sidewall rings which are made by injection molding will generally be from about 60 mils to about 125 mils thick and will preferably be from about 70 mils to about 90 mils thick.
The present invention will be described in more detail in the following examples. The subject invention will also be contrasted to other possible techniques for affixing decorative appliques to the sidewalls of tires in certain comparative examples which are included. These examples are merely for the purpose of illustrating the subject invention and are not to be regarded as limiting the scope of the subject invention or the manner in which it can be practiced. Unless specifically indicated otherwise, all parts and percentages are given by weight.
EXAMPLE 1
A SPBD/rubber blend containing 50 weight percent SPBD, 30 weight percent chlorobutyl rubber, 17.5 weight percent natural rubber and 2.5 weight percent EPDM rubber, based upon total polymers, was prepared using conventional Banbury mixing procedures for non-productive and productive batches. The SPBD/rubber blend also contained 4.75 phr of processing oils, 1.0 phr of antioxidants, 1.0 phr of stearic acid, 27.5 phr of clay, 37.5 phr of titanium dioxide, 0.175 phr of a blue pigment, 5.0 phr of zinc oxide, 1.2 phr of sulfur, and 1.54 phr of an accelerator. The SPBD utilized in this example had a melting point of 123° C. It should be noted that the SPBD utilized in accordance with this invention is a crosslinking thermoplastic resin. However, SPBD is considered to be a rubber in calculating phr (parts per hundred parts of rubber).
The SPBD/rubber blend was Banbury mixed and milled into continuous strips. The strips were then used in injection molding equipment to obtain white sidewall quarter segments which were 65 mils thick. This injection molding process involves heating the SPBD/rubber blend in a temperature controlled barrel and injection of the hot SPBD/rubber blend into a cooler mold to permit the recrystallization of the SPBD. After molding, the white sidewall quarter segment was considered to be dimensionally stable and was stiff in the uncured state. The white sidewall quarter segments made had minimal green tack adhesion to themselves and did not stick together.
A 75 ton Van Dorn injection molding machine was used in making the white sidewall segments. In a typical molding cycle, the operator closes the safety gate located at the clamp/mold area which activates the molding cycle start. The clamp moves forward closing the mold halves and builds sufficient force (clamp tonnage) to hold the mold halves closed against the high injection pressure of the polymer blend into the mold cavity. The SPBD/rubber blend is forced into the mold cavity by the forward motion of the reciprocating screw. Pressure and injection rates are very high initially in order to completely fill the mold cavity before the melt begins to cool and set-up. In fact, pressure can reach as high as 20,000 psi (1.379×10 8 Pascals). After the mold cavity is almost filled, the pressure and fill rate are reduced to accomplish final filling (hold pressure) and packing the mold cavity. When the cavity sprue gates have solidified, the injection pressure is relieved.
The screw within the injection unit simultaneously rotates to build a shot for injection in the next cycle. While this is occurring, SPBD/rubber blend that has been injected into the mold cavity is cooling and solidifying. After sufficient cooling time, the clamping mechanism is released, the mold is opened and the white sidewall ring segment is removed. The gate is then closed to initiate another cycle.
The injection molding conditions which were typically used are as follows:
______________________________________Barrel temperature 285° F. (141° C.)Mold temperature 160° F. (71° C.)Injection pressure 13,000 psi (8.96 × 10.sup.7 Pa)Holding pressure 7000 psi (4.83 × 10.sup.7 Pa)Back pressure 50 psi (3.44 × 10.sup.5 Pa)Injection forward time 2 secondsHolding pressure time 8 secondsMold shut time 300 secondsScrew speed 45 rpm______________________________________
The mold is designed such that two quarter ring segments are molded at the same time using a single gated cold runner system. White sidewall rings were assembled from the segments with overlapping tabs being bonded together with a gum stock or latex adhesive.
The white sidewall rings made were placed in the recessed groove of a standard tire mold. A standard blackwall P195/75R14 uncured tire was then placed onto the deflated bladder of the tire mold. The mold was closed and the bladder was inflated thereby bringing the green (uncured) tire into contact with the white sidewall ring. The tire was then cured using a mold temperature of 315° F. (157° C.), a bladder temperature of 340° F. (171° C.), and a bladder pressure of 300 psi (2.07×10 6 Pascals). The tire was cured utilizing a cycle time of 13.2 minutes.
The tire was then removed from the tire mold. Over 175 tires were successfully built and cured utilizing this procedure. The molded tires exhibited desirable mold release with no blisters or delaminations, excellent mold surface detail with good location of the white sidewall and excellent adhesion.
The tires built were subjected to a series of tests to evaluate the performance and integrity of the white sidewall. The tires passed Department of Transportation (DOT) Endurance FMVSS-109 at full and half tire inflation pressure with no evidence of white sidewall defects. In addition, the DOT High Speed FMVSS-109 test was run with no signs of white sidewall failure.
The tires were also subjected to additional tests. Test tires exceed more than 40,000 miles on the Outdoor Resiliometer (ODR) without failure due to white sidewall delaminating and/or cracking. The experimental test tires were subjected to 300 hours of whole tire ozone chamber testing (50 parts per hundred million of O 3 ) and exhibited no signs of failure due to cracking.
The tires built utilizing the procedure of this invention were satisfactory in every way. Additionally, the tires built were superior to conventional white sidewall tires in several respects. For instance, the tires built utilizing the process of this invention were more uniform than standard whitewall tires. For example, they possess better balance from side to side. The removal of standard white sidewall compounds also eliminates problems associated with modulus transitions due to widely different compounding materials within the sidewall construction. The potential for the white splice in standard whitewall tires to open during curing and consequently causing a defect was also eliminated. Misalignment of the white sidewall material relative to the mold groove is a frequently encountered problem in conventional techniques for building whitewall tires which is also eliminated.
EXAMPLE 2
A blend containing 50 weight percent SPBD and 50 weight percent rubbers was prepared. The SPBD which was utilized had a melting point of 123° C. The rubber component utilized in the blend contained 60% chlorobutyl rubber, 35% natural rubber, and 5% EPDM rubbers. The blend prepared also contained about 1 phr of an antioxidant, about 37.5 phr of titanium dioxide (a white pigment), 27.5 phr of clay, about 0.5 phr of stearic acid, about 3.75 phr of zinc oxide, about 0.9 phr of sulfur, and about 1.16 phr of an accelerator. It should be noted that the SPBD utilized in accordance with this invention is a crosslinking thermoplastic resin and is considered to be a rubber in calculating phr (parts per hundred parts of rubber).
The SPBD/rubber composition blend was milled and calendared into a continuous sheet. A clicking die having a curvature which matched that of the recessed groove in the tire mold was used. Segmented strips were then spliced together to form a ring which was placed in the recessed groove of a standard tire mold. A standard blackwall P195/75R14 uncured tire was then placed onto the inflating bladder of the tire mold. The mold was closed and the bladder was inflated, thereby bringing the green tire into contact with the white sidewall ring. The tire was then cured at a mold temperature of 315° F. (157° C.), a bladder temperature of 340° F. (171° C.) and at a bladder pressure of 300 psi (2.07×10 6 Pascals). The tire was cured utilizing a cycle time of 13.2 minutes.
The tire was then removed from the tire mold. Nine additional tires were successfully built and cured utilizing the same procedure. The white sidewalls on the tires made were precisely located with excellent mold detail and surface smoothness being obtained. The white SPBD/rubber blend flowed into the vent holes of the mold which is a good indication of melt flow. Excellent mold release was observed with no blisters or delaminations. Additionally, the splices between the ring segments were almost invisible. It should be noted, however, that such splices could be easily eliminated by preparing one piece ring structures. Adhesion was also adequate on demolding because there were no separations caused by pulling the tire out of the mold.
The tires built were subjected to the G05 Department of Transportation (DOT) endurance test for full and half tire inflation pressure and passed with no evidence of white sidewall cracking. A test tire also completed 300 hours of whole tire ozone chamber testing with no evidence of failure. The tires tested also passed outdoor resiliometer testing for failure due to sidewall delamination and/or cracking. Test tires were also subjected to a very severe curb scuff test. In this test the tire's white sidewalls were run against an abrasive curb surface for 200 feet (61 meters). After completion of the test, inspection of the tires revealed no adhesion loss between the white sidewall ring and the tire. However, some of the white SPBD/rubber composition was worn away to expose the black sidewall. This was, however, expected in such a severe test.
The tires built utilizing the procedure of this invention were satisfactory in every way. Additionally, the tires built were superior to conventional white sidewall tires in several respects. For instance, the tires built utilizing the process of this invention were more uniform than standard whitewall tires. For example, they possess better balance from side to side. The removal of standard white sidewall compounds also eliminates problems associated with modulus transitions due to widely different compounding materials within the sidewall construction. The potential for the white splice in standard whitewall tires to open during curing and consequently causing a defect was also eliminated. Misalignment of the white sidewall material relative to the mold groove is a frequently encountered problem in conventional techniques for building whitewall tires which is also eliminated.
Comparative Example 3
Tires were built utilizing the procedure described in Example 1 except that the white sidewall rings were made without including SPBD in the blend. It was readily determined that tires could not be made in this manner because the uncured white sidewall rings simply could not be handled.
Comparative Example 4
In this experiment, tires were built utilizing the procedure described in Example 1 except that the white sidewall rings were made with a blend which did not include SPBD. In an attempt to overcome the problem described in Comparative Example 1, the white sidewall rings were precured. Tires were successfully built. However, the tires made utilizing this procedure failed the curb scuff test. This was because there was inadequate adhesion between the precured white sidewall ring and the tire. This example shows that it is not viable to precure decorative tire sidewall appliques because unsatisfactory adhesion results. By including SPBD in the blend used in making the decorative applique, it is not necessary to precure the applique prior to affixing it to the tire sidewall.
EXAMPLES 5-13
SPBD imparts properties to green rubber that are desirable for improved handling characteristics for in mold applied white sidewall rings. The addition of SPBD having a melting point of 115° C., 123° C. or 141° C. at any level results in reduced tack, increased stiffness, and increased static modulus for green stocks. In this series of experiments, various levels of SPBD were blended with a rubber blend containing 60% chlorobutyl rubber, 35% natural rubber and 5% EPDM rubber. The physical properties of the uncured SPBD/rubber blends made are reported in Table I.
TABLE I__________________________________________________________________________SPBD SPBD Tensile* 100%* 300%*Examplem.p., °C. Level, % Strength Elongation, % Modulus Modulus__________________________________________________________________________5 -- 0 145 >900 75 1056 115 20 350 805 275 3057 115 33 515 490 385 4958 115 50 820 400 575 7059 123 33 390 390 280 38010 123 50 740 510 470 60011 123 67 1220 580 740 89012 141 33 410 330 310 40013 141 50 830 310 670 820__________________________________________________________________________ *in pounds per inch.sup.2
Example 5 was done as a control and did not include any SPBD. Tensile strength and elongation were determined by ASTM D-412. As can be seen, the incorporation of SPBD into the rubber blend yields high green strength and stiffness without the need for precure.
The SPBD/rubber blends made were then compounded with 1.0 phr of antioxidants, 1.0 phr of stearic acid, 27.5 phr of clay, 37.5 phr of titanium dioxide, 0.175 phr of a blue pigment, 5.0 phr of zinc oxide, 1.2 phr of sulfur, and 1.54 phr of an accelerator. The productive compounds made were then cured and the physical properties of the cured samples are reported in Table II.
TABLE II__________________________________________________________________________ Tensile.sup.a 50%.sup.a Trouser.sup.b Strebler.sup.c DIN.sup.dExampleShore A Strength Elongation, % Modulus Tear Adhesion Abrasion__________________________________________________________________________5 56 1190 560 180 60 50 3706 70 1440 600 340 65 60 3307 77 1460 540 480 70 70 3308 85 1730 520 690 105 65 2809 77 1590 570 450 90 50 32010 85 1920 530 690 120 90 26011 90 2220 505 885 185 105 20012 80 1580 210 580 95 50 28513 89 1850 390 920 140 100 195__________________________________________________________________________ .sup.a in pounds/inch.sup.2 .sup.b in pounds/inch .sup.c in pounds/inch width .sup.d in mm.sup.3 (relative loss)
The SPBD modified compounds exhibited increased tear, hardness and static modulus as well as improved abrasion resistance and enhanced adhesion to a black sidewall compound. The cured SPBD modified compounds showed physical properties which are superior for white sidewall applications.
SPBD compounds can be processed on conventional Banbury mixers, mills, calendering equipment and injection molders. However, higher processing temperatures are required depending upon the SPBD melting point range. For this reason, extending the scorch time is beneficial. The cure system used in the SPBD/rubber blend should, therefore, be adjusted to match the cure performance of a conventional white sidewall, otherwise delaminations and/or blisters may occur upon demolding the tire from the mold at the end of the curing cycle. Monsanto cure properties of the productive compounds made are reported in Table III.
TABLE III______________________________________ Torque.sup.b Torque.sup.b Delta.sup.bExample T.sub.2.sup.a T.sub.25.sup.a T.sub.90.sup.a Maximum Minimum Torque______________________________________5 5.1 8.0 19.7 25.1 5.9 19.26 6.8 10.7 19.8 26.0 4.8 21.27 6.5 10.6 18.1 25.0 4.9 20.18 7.4 10.7 19.8 24.2 3.8 20.49 7.6 10.1 22.9 26.5 7.7 18.810 7.5 8.9 19.8 26.0 7.7 18.311 7.0 9.0 19.2 26.6 7.8 19.012 7.5 10.0 23.3 29.8 11.6 18.213 7.6 10.7 24.5 34.0 15.7 18.3______________________________________ .sup.a Reported in minutes .sup.b decinewton · meters (dN · m)
The Monsanto Cure Rheometer was run at 302° F. (150° C.), 1 degree arc and 100 cycles per minute for a 60 minute test period. The cure packages used in the compounds listed in Table III were adjusted to reflect the addition of SPBD to the compound. The SPBD is treated as a crosslinkable polymer and not as a filler additive. The SPBD/rubber compound should have a cure time (T90) which is essentially equivalent to that of a standard white sidewall compound used in the black sidewall of a conventional tire.
EXAMPLE 14
In this procedure, tires having decorative appliques on the sidewalls thereof were prepared. Goodyear's Wingfoot® design was applied to the tire sidewalls in this procedure.
An experimental steel rule clicking die for the Goodyear logo was constructed. The Wingfoot® design was omitted for simplicity. Letters in the logo had a height of about 0.80 inches.
The SPBD/rubber compound utilized in making the logo was prepared by mixing 50 parts of SPBD (having a melting point of 141° C.), 30 parts of halobutyl rubber, 17.5 parts of natural rubber, 2.5 parts of EPDM rubber, 1 part of an antioxidant, 4.75 parts of processing aids (oils and waxes), 27.5 parts of clay, 37.5 parts of titanium dioxide, 0.175 parts of blue pigment, 3.75 parts of zinc oxide, 0.90 parts of sulfur, 1.15 of a primary accelerator and 0.30 parts of a secondary accelerator. These SPBD/rubber blends were prepared by utilizing standard Banbury mixing techniques for non-productive and productive compounds. The blends were milled into continuous sheets. However, such sheets could also be prepared by calendering. The temperature used in the milling procedure was somewhat higher than temperature normally required because of the melting point and amount of SPBD utilized in the blend. The logo was clicked out from the sheets using the appropriate clicking die. The logos prepared had a typical thickness of about 30 mils. After the letters were clicked out, the scrap stock was removed and the letters were transferred to a conventional rubber stock (having a thickness of 30 mils) by contact. The rubber stock utilized should be soft and tacky to provide adequate properties as the backing stock which can also serve as a stain-barrier compound. The decorative applique was applied to the tire sidewall components before the tire was built. In other instances, the decorative applique was applied to green tires before shaping, or to green tires after shaping or by placing the applique into the tire mold before placing the tire therein.
The green tires were cured utilizing standard techniques. The decorative designs on the tires built maintained distinctness after curing with only minimal distortion. When logos were placed on a non-shaped tire, the letters radiused nicely upon shaping and remained tacked to backing stocks. When the tires were placed in the tire mold or applied to the shaped green tire, the resulting logo was molded directly into the rubber with very little distortion. Based upon tire molding, the best results for letter definition were obtained for compounds containing 50% SPBD having a melting point of 141° C. Logos which were prepared utilizing SPBD having a melting point of 123° C showed more of a tendency toward flowing and distorting but were also deemed to be acceptable.
The radial medium truck tires which were built were tested for ozone resistance and bead area durability. After 300 hours of testing in an ozone chamber, the logos exhibited some cracking but it was no worse than was experienced on the sidewalls of the tires. No edge separation occurred with the logos. Logos which were prepared utilizing SPBD having a melting point of 141° C. experienced slightly more cracking than those prepared utilizing the SPBD having a melting point of 123° C. but was not considered to be objectionable. Truck tires which were built utilizing this procedure have completed 11,000 miles of bead out durability testing. The logos were positioned in the lower sidewall, the middle sidewall and the upper sidewall of test tires. No cracking of the logos was observed regardless of the position in the sidewall for the compounds which were made utilizing SPBD having a melting point of 123° C. or 141° C. Based upon these test results, the more preferred location for truck tire logo placement is on the upper sidewall near the gravel guard groove. It was also determined that the logos should be streamlined and radiused in critical areas such as corners to eliminate points of stress concentration.
EXAMPLE 15
In this experiment P195/75R14 tires were made using the technique described in Example 1, except the SPBD utilized had a melting point of only 92° C. The procedure used in this example also differed from the procedure of Example 1 in that a whole white sidewall ring having a thickness of 85 mils was made by injection molding. The tires made were equivalent to the tires made in Example 1. This example shows that SPBD having a melting point of only 92° C. can be used in the practice of this invention. It also shows that one-piece white sidewall rings can be made by injection molding.
While certain representative embodiments and details have been shown for the purpose of illustrating the subject invention, it will be apparent to those skilled in this art that various changes and modifications can be made therein without departing from the scope of the subject invention. | Tires having white sidewalls are very popular in the United States and Canada. Tires having white lettering thereon are also very popular. This invention discloses a process for preparing such tires having decorative appliques thereon. By practicing the process of this invention, tires having better uniformity can be built at lower costs than when standard tire building techniques are utilized. This invention specifically relates to a method of preparing a pneumatic rubber tire having a decorative design on the sidewall thereof which comprises (a) applying the decorative applique to the sidewall of an uncured tire and (b) curing the tire; wherein the decorative applique is comprised of from about 25 weight percent to about 75 weight percent syndiotactic 1,2-polybutadiene having a melting point which is within the range of about 70° C. to about 160° C. and from about 25 weight percent to about 75 weight percent of at least one polydiene rubber which is cocurable with said syndiotactic 1,2-polybutadiene, sulfur, zinc oxide and at least one pigment or colorant. | 8 |
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention is related to a machine and a method of plaiting threads resulting in braids, wherein thread can be made of all types of materials, e.g., cotton, metal, synthetic polymers, alloys, carbon, etc. Therefore, the machine and the method of the present invention would be used in a broad variety of industries.
[0003] 2. Description of Prior Art
[0004] Machines to make braids have the limitation of being complex machines because the braids are made from filament, threads, strands, or fibers provided by a reels or cylinders, wherein the each reel or cylinder is physically connected to an element which moves around the reel or cylinder the filament from each reel or cylinder is released, wherein the multiples released filaments form braid. This need of a physical contact element to move the reels or cylinders in such a way that braids are formed make this kind of machines costly not only to make, but also to maintain. An example of this type of braiding machine is described by Leon Bettger, J. et al. in U.S. Pat. No. 6,360,644.
[0005] The present invention overcomes the above mentioned limitation, the need of a physical contact element to move the reels or cylinders that provide the threads or filaments which would form a braid.
SUMMARY OF THE INVENTION
[0006] The present invention provides a machine and method wherein there is no physical contact between one or more thread or filaments reels and the element that generates the movement of said reel or reels in such a way that the thread or filament provided by said reel or reels can form a braid. The element that generates the movement of the reel or reels have a magnetic constituent, wherein the magnetic constituent remotely pulls into moving the device or devices holding the reel or reels.
[0007] Specifically, the present invention provides a machine for plaiting, wherein a first embodiment of the machine comprises:
A. A circular movement platform, wherein the circular movement platform has on top at least one fixed thread reel that moves along a first circumference path with the platform, wherein the platform has a center leg, wherein the platform and the center leg are moved circularly by a first motor that moves the center leg and the platform in a circular movement; B. At least one magnetic stand, wherein the magnetic stand serves as the base for a magnetic stand based thread reel, wherein the magnetic stand lies unattached over the platform, wherein the magnetic stand moves freely over the platform; and, C. At least one arm with at least one control magnet, wherein the control magnet is immediately underneath the platform exactly below the magnetic stand, wherein the control magnet is moved circularly by a second motor, wherein the control magnet emits a magnetic force that moves the magnetic stand in a independent circular movement, and wherein the control magnet and the magnetic stand follow the same synchronous independent circular movement;
[0011] Wherein the magnetic stand based thread reel releases a first thread end, wherein the fixed thread reel releases a second thread reel, wherein, as the magnetic stand moves circularly, the first thread end and the second thread end form a braid.
[0012] In one aspect of the machine of the present invention, the braid is rolled into a braid reel.
[0013] In another aspect of the machine of the present invention, the at least one arm has at least two control magnets, wherein the machine also has at least two magnetic stands, wherein the at least two magnetic stands move following an independent circular movement, wherein the at least two magnetic stands are opposite an symmetrically positioned on the imaginary circular perimeter of the independent circular movement, wherein the at least two control magnets are immediately underneath the platform, wherein the at least two control magnets are exactly below the at least two magnetic stands, wherein the at least two control magnets govern the independent circular movement of the at least two magnetic stands.
[0014] In one more aspect of the machine of the present invention, the arm is supported on a wing, wherein the arm is on the wing end, wherein the wing is attached to an axial support, wherein the second motor is at the wing body, wherein the wing and the axial support move following a circular movement around the same axis of the circular movement of the center leg and the platform, wherein the machine also has a third motor that moves circularly the wing and the axial support, wherein the circular movement of the wing displaces the control magnet circularly, wherein the control magnets pulls the magnetic stand making the magnetic stand to move following a displacement movement over the platform, wherein the magnetic stand circular movement is independent of the magnetic stand displacement movement, wherein the magnetic stand displacement movement is along a second circumference path, wherein the first circumference path and the second circumference path are parallel.
[0015] In a second embodiment of the machine for plaiting of the present invention, the machine comprises:
A. A fixed platform that has on top at least one fixed thread reel, wherein the fixed thread reel is positioned in a point that coincides with perimeter line of a first circumference path; B. At least one magnetic stand, wherein the magnetic stand serves as support for a magnetic stand based thread reel, wherein the magnetic stand lies unattached over the platform, wherein the magnetic stand moves freely over the platform; C. At least one circular movement wing with an axial support, wherein the circular movement wing with the axial support is moved by a center motor, wherein at the end of the circular movement wing there is a independent circular movement arm controlled by a wing motor located at said wing body, wherein at the independent circular movement arm there is at least one control magnet, wherein the control magnet is underneath the platform, wherein the control magnet is exactly below the magnetic stand, wherein, as the arm moves circularly, the control magnet moves circularly; wherein the wing circular movement around the axial support displaces the arm with control magnet around the axial support, wherein the control magnet emits a force that pulls the magnetic stand to move following a displacement movement over the platform, wherein the control magnet force also pulls the magnetic stand into an independent circular movement, wherein both, the control magnet, and the magnetic stand, have the same synchronous circular movement and the same displacement movement, and wherein the magnetic stand displacement movement over the platform follows a second circumference path, wherein the first circumference path and the second circumference path are parallel;
[0019] Wherein the magnetic stand based thread reel releases a first thread end, wherein the fixed thread reel releases a second thread reel, wherein, as the magnetic stand moves circularly, the first thread end and the second thread end form a braid.
[0020] In an aspect of the second embodiment of the machine of the present invention, the braid is rolled into a braid reel.
[0021] In another aspect of the second embodiment of the machine of the present invention, at the independent movement arm there is at least two control magnets, wherein the at least two control magnets are underneath the platform, wherein the machine also has at least two magnetic stands that serve as bases for two thread reels, wherein the at least two magnetic stands lie unattached on top of the platform, wherein at least two magnetic stands move freely on top of the platform, wherein at least two magnetic stands are exactly above the at least two control magnets, wherein the at least two control magnets emit a force that pulls the at least two magnetic stands, wherein both, the control magnets, and the magnetic stands, have the same synchronous circular movement and the same displacement movement.
[0022] The present invention also provides a method of plaiting braids in a machine, wherein the machine comprises:
A. A platform B. At least one magnetic stand lying on top of the platform, wherein on top of the magnetic stand there is a magnetic stand based thread reel, C. At least one fixed thread reel attached on top of the platform; D. A least one control magnet underneath the platform, wherein the control magnet is exactly below the magnetic stand, wherein the control magnet is on an arm, wherein the arm is moved circularly by a motor, wherein the control magnet emits a magnetic force that pulls the magnetic stand, wherein the magnetic stand also moves circularly and synchronously with the control magnet, wherein the magnetic stand thread reel releases a first thread end, and wherein fixed thread reel releases a second thread reel, wherein, as the magnetic stand moves circularly, the first thread end and the second thread end form a braid.
[0027] In an aspect of the method of the present invention, the arm has at least two control magnets, and the machine also has two magnetic stands with magnetic stand based thread reels, wherein the two control magnets are positioned opposite on the arm, wherein the two magnetic stands are also opposite positioned exactly on top of the control magnets.
[0028] In another aspect of the method of the present invention, the fixed thread reel moves with the platform, wherein the fixed thread reel moves along a first path, wherein, after, the fixed thread reel passes along the first path at a first point next to the magnetic stand, the magnetic stand moves circularly.
[0029] In an additional aspect of the method of the present invention, the control magnet and the magnetic stand together have a second displacement movement that follows a second path, wherein, after, the magnetic stand passes along the second path at a second point next to the fixed thread reel, the magnetic stand moves circularly.
[0030] In one more aspect of the method of the present invention, the fixed thread reel moves with the platform, wherein the fixed thread reel moves along a first path, wherein, after, the fixed thread reel passes along the first path at the first point where the fixed thread reel is between the two magnetic stands, the magnetic stands move circularly.
[0031] In another aspect of the method of the present invention, the two control magnets and the two magnetic stands together have a second displacement movement that follows a second path, wherein, after, the magnetic stands pass along the second path at a second point next to the fixed thread reel, having passed the fixed thread reel between the two magnetic stands, the magnetic stands move circularly.
[0032] Additional objectives and advantages of the present invention will be more evident in the detailed description of the invention and the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033] FIG. 1 . shows a transversal view a first embodiment of the machine of the present invention.
[0034] FIG. 2 . shows a tridimensional view of the first embodiment of the present invention.
[0035] FIG. 3 . shows a transversal view of a variation of a first embodiment of the machine of the present invention.
[0036] FIG. 4 . shows a tridimensional view of a variation of the first embodiment of the present invention.
[0037] FIG. 5 . shows a transversal view of a second embodiment of the machine of the present invention.
[0038] FIG. 6 . shows a tridimensional view of the second embodiment of the present invention.
[0039] FIG. 7 . shows a diagrammatic top view of the machine of the present invention to illustrate the method of the present invention.
[0040] FIG. 4 . shows another diagrammatic top view of the machine of the present invention to illustrate the method of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0041] FIGS. 1 and 2 show a first embodiment of the machine for plaiting of the present invention, wherein the machine comprises:
A. A circular movement platform ( 1 A), wherein the circular movement platform ( 1 A) has on top at least one fixed thread reel ( 2 ) that moves along a first circumference path ( 3 arrow indicating displacement with the platform movement) with the platform ( 1 A), wherein the platform ( 1 A) has a center leg ( 4 ), wherein the platform ( 1 A) and the center leg ( 4 ) are moved circularly ( 5 arrow indicating platform movement) ( FIG. 8 ) by a first motor ( 6 ) that moves the center leg ( 4 ) and the platform ( 1 A) in a circular movement ( 5 ); B. At least one magnetic stand ( 7 ), wherein the magnetic stand ( 7 ) serves as the base for a magnetic stand based thread reel ( 8 ), wherein the magnetic stand ( 7 ) lies unattached over the platform ( 1 A), wherein the magnetic stand ( 7 ) moves freely over the platform ( 1 A; and, C. At least one arm ( 9 ) with at least one control magnet ( 10 ), wherein the control magnet ( 10 ) is immediately underneath the platform ( 1 A) exactly below the magnetic stand ( 7 ), wherein the control magnet ( 10 ) is moved circularly by a second motor ( 11 ), wherein the control magnet ( 10 ) emits a magnetic force that moves the magnetic stand ( 7 ) in a independent circular movement ( 12 ) ( FIGS. 7 and 8 ), and wherein the control magnet ( 10 ) and the magnetic stand ( 7 ) follow the same synchronous independent circular movement ( 12 circular arrow indicating circular movement);
[0045] Wherein the magnetic stand based thread reel ( 8 ) releases a first thread end ( 13 ), wherein the fixed thread reel ( 2 ) releases a second thread reel ( 14 ), wherein, as the magnetic stand ( 7 ) moves circularly ( 12 ), the first thread end ( 13 ) and the second thread end ( 14 ) form a braid ( 15 ).
[0046] The fixed thread reel ( 2 ) is fixedly attached to the top of the platform ( 1 A) y ( 1 B)( FIGS. 5 and 6 ), wherein the fixed thread reel ( 2 ) does not move freely on top of the platform ( 1 A) y ( 1 B).
[0047] For the purpose of this patent application, the term thread is synonymous to other similar terms such as filament, strand, string, fiber, etc.
[0048] In all cases in this patent application, the term reel means a reel, a cylinder or any device around or over which a thread or a braid can be stored, hoarded, gathered, or rolled.
[0049] For the purposes of this patent application, threads can be made of all types of materials, e.g., cotton, wool, metal, synthetic polymers, alloys, carbon, etc. Therefore, the machine and the method of the present invention would be used in a broad variety of industries.
[0050] For the purpose of this patent application, the term “magnetic stand” indicates that the stand is made of any material that can be attracted by a magnetic force emitted by a magnet. The magnetic stand is not attached on top of the platform, and preferably is made of a material which has very low friction with respect to the surface of the platform ( 1 A) y ( 1 B), wherein the magnetic stand ( 7 ) slides without effort on top of the platform ( 1 A) y ( 1 B).
[0051] For the purpose of this patent application the term “control magnet” indicates that the control magnet ( 10 ) is made of any material that can emit a magnetic form. For example, a preferably material of which the control magnet ( 10 ) is made could be neodymium magnetic material.
[0052] In one aspect of the machine of the present invention, the braid ( 15 ) is rolled into a braid reel ( 16 ).
[0053] In another aspect of the machine of the present invention, the at least one arm ( 9 ) has at least two control magnets ( 10 ), wherein the machine also has at least two magnetic stands ( 7 ), wherein the at least two magnetic stands ( 7 ) move following an independent circular movement ( 12 ), wherein the at least two magnetic stands ( 7 ) are opposite an symmetrically positioned ( FIGS. 7 and 8 A and B) on the imaginary circular perimeter of the independent circular movement, wherein the at least two control magnets ( 10 ) are immediately underneath the platform ( 1 A) y ( 1 B), wherein the at least two control magnets ( 10 ) are exactly below the at least two magnetic stands ( 7 ), wherein the at least two control magnets ( 10 ) govern the independent circular movement ( 12 ) of the at least two magnetic stands ( 7 ).
[0054] FIGS. 3 and 4 show a variation of the first embodiment of the machine of the present invention, wherein the arm ( 9 ) is supported on a wing ( 17 ), wherein the arm ( 9 ) is on the wing end ( 17 A), wherein the wing ( 17 ) is attached to an axial support ( 18 ), wherein the second motor ( 11 ) is at the wing body ( 17 B), wherein the wing ( 17 ) and the axial support ( 18 ) move following a circular movement around the same axis of the circular movement of the center leg ( 4 ) and the platform ( 1 A), wherein the machine also has a third motor ( 19 ) that moves circularly the wing ( 17 ) and the axial support ( 18 ), wherein the circular movement of the wing ( 17 ) displaces the control magnet ( 10 ) circularly, wherein the control magnet ( 10 ) pulls the magnetic stand ( 7 ) making the magnetic stand ( 7 ) to move following a displacement movement ( 20 indicating displacement) ( FIG. 7 ) over the platform ( 1 A), wherein the magnetic stand ( 7 ) circular movement ( 12 ) ( FIGS. 7 and 8 ) is independent of the magnetic stand ( 7 ) displacement movement ( 20 ), wherein the magnetic stand ( 7 ) displacement movement ( 20 ) is along a second circumference path ( 20 ), wherein the first circumference path ( 3 ) and the second circumference path ( 20 ) are parallel.
[0055] In all instances in the present application, preferably, the second motor ( 11 ) or later referred in paragraph 0042 C. as a wing motor ( 11 ) is positioned on the wing body ( 17 B). However, the term “at the wing body” means that said second motor or wing motor ( 11 ) could also be located in any appropriate position in or on the wing ( 17 ), e.g., on top of the wing, inside the body of the wing, etc.
[0056] Despite of the fact that the circular platform ( 1 A and 1 B), and the displacement along the first circumference path ( 3 ) and the displacement along the second circumference path ( 20 ) is the most efficient and preferably in the design of the machine of the present invention, it is possible to replace a circular platform and the movements along the first circumference path ( 3 ) and the second circumference path ( 20 ) with a platform that does not move circularly, but a platform that is rectangular and moves longitudinally, and displacement movements of fixed and rotating reels along a first path and a second path that are longitudinally and parallel.
[0057] FIGS. 6 and 7 show a second embodiment of the machine for plaiting of the present invention, wherein the machine of the second embodiment comprises:
A. A fixed platform ( 1 B) that has on top at least one fixed thread reel ( 2 ), wherein the fixed thread reel ( 2 ) is positioned in a point that coincides with perimeter line of a first circumference path ( 3 ) ( FIG. 8 ); B. At least one magnetic stand ( 7 ), wherein the magnetic stand ( 7 ) serves as support for a magnetic stand based thread reel ( 8 ), wherein the magnetic stand ( 7 ) lies unattached over the platform ( 1 B), wherein the magnetic stand ( 7 ) moves freely over the platform ( 7 B); C. At least one circular movement wing ( 17 ) with an axial support ( 18 ), wherein the circular movement wing ( 7 ) with the axial support is moved by a center motor ( 19 ), wherein at the end of the circular movement wing ( 17 A) there is a independent circular movement arm ( 9 ) controlled by a wing motor ( 11 ) located at said wing body ( 17 B), wherein at the independent circular movement arm ( 9 ) there is at least one control magnet ( 10 ), wherein the control magnet ( 10 ) is underneath the platform ( 1 B), wherein the control magnet ( 10 ) is exactly below the magnetic stand ( 7 ), wherein, as the arm ( 7 ) and the control magnet ( 10 ) move circularly; wherein the wing ( 17 ) circular movement around the axial support ( 18 ) displaces the arm ( 9 ) with control magnet ( 10 ) around the axial support ( 18 ), wherein the control magnet ( 10 ) emits a force that pulls the magnetic stand ( 7 ) to move following a displacement movement over the platform ( 20 ), wherein the control magnet ( 10 ) force also pulls the magnetic stand ( 7 ) into an independent circular movement, wherein both, the control magnet ( 10 ), and the magnetic stand ( 7 ), have the same synchronous circular movement and the same displacement movement ( 20 ), and wherein the magnetic stand ( 7 ) displacement movement over the platform ( 1 B) follows a second circumference path ( 20 ), wherein the first circumference path ( 3 ) and the second circumference path are parallel ( 20 )(Although is this second embodiment the platform does not move around since it is fixed ( FIGS. 5 and 6 ), and therefore the fixed thread reel does not move either, a first circumference path is mentioned to indicate that if an imaginary circumference perimeter is traced, it will coincide with a circumference path as if the fixed thread reel would move);
[0061] Wherein the magnetic stand based thread reel ( 8 ) releases a first thread end ( 13 ), wherein the fixed thread reel ( 2 ) releases a second thread reel ( 14 ), wherein, as the magnetic stand ( 7 ) moves circularly, the first thread end ( 13 ) and the second thread end ( 14 ) form a braid ( 15 ).
[0062] In an aspect of the second embodiment of the machine of the present invention, the braid ( 15 ) is rolled into a braid reel ( 16 ).
[0063] In another aspect of the second embodiment of the machine of the present invention, at the independent movement arm ( 9 ) there is at least two control magnets ( 10 ), wherein the at least two control magnets ( 10 ) are underneath the platform ( 1 B), wherein the machine also has at least two magnetic stands ( 7 ) that serve as bases for two thread reels ( 8 ), wherein the at least two magnetic stands ( 7 ) lie unattached on top of the platform ( 1 B), wherein at least two magnetic stands ( 7 ) move freely on top of the platform ( 1 B), wherein at least two magnetic stands ( 7 ) are exactly above the at least two control magnets ( 10 ), wherein the at least two control magnets ( 10 ) emit a force that pulls the at least two magnetic stands ( 7 ), wherein both, the control magnets ( 10 ), and the magnetic stands ( 7 ), have the same synchronous circular movement ( 12 ) and the same displacement movement ( 20 ).
[0064] In all cases of the present application, the first ( 6 ), second (wing motor) ( 11 ) and third ( 19 ) motors can be controlled and synchronized in order to obtain precise movements of the center leg ( 4 ) and the circularly moving platform ( 1 A), the arm ( 9 ), and the wing ( 17 ) and the axial support ( 18 ), either by analogous or digital means, e.g., PLC (programmable logic control), computer numeric control, etc.
[0065] In all cases in the present application, depending on the number of magnetic stands ( 7 ) (which will be equal to the number of control magnets ( 10 )) per arm ( 9 ), the rotating movement ( 12 ) of each magnetic stand would be different, e.g., more than 180 degrees when there is only one magnetic stand, 180 degrees or less when there are two magnetic stands, 120 degrees or less when there are three magnetic stands, and so on.
[0066] The present invention also provides a method of plaiting braids in a machine, wherein the method is mainly illustrated in diagrams of FIGS. 7 and 8 ( FIGS. 1-6 show additional illustrative details), wherein the machine comprises:
E. A platform ( 1 A or 1 B) F. At least one magnetic stand ( 7 ) lying on top of the platform ( 1 A or 1 B) (although, preferably the platform is circular, the platform could also have a different geometrical perimeter as explained in paragraph 0041), wherein on top of the magnetic stand ( 7 ) there is a magnetic stand based thread reel ( 8 ), G. At least one fixed thread reel ( 2 ) attached on top of the platform ( 1 A or 1 B); H. A least one control magnet ( 10 ) underneath the platform ( 1 A or 1 B), wherein the control magnet ( 10 ) is exactly below the magnetic stand ( 7 ), wherein the control magnet ( 10 ) is on an arm ( 9 ), wherein the arm ( 9 ) is moved circularly by a motor ( 11 ), wherein the control magnet ( 10 ) emits a magnetic force that pulls the magnetic stand ( 7 ), wherein the magnetic stand ( 7 ) also moves circularly and synchronously with the control magnet ( 10 ), wherein the magnetic stand thread reel ( 8 ) releases a first thread end ( 13 ), and wherein fixed thread reel ( 2 ) releases a second thread reel ( 14 ), wherein, as the magnetic stand ( 7 ) moves circularly ( 12 ), the first thread end ( 13 ) and the second thread end ( 14 ) form a braid ( 15 ).
[0071] In an aspect of the method of the present invention, the arm has at least two control magnets ( 10 ), and the machine also has two magnetic stands ( 7 ) with magnetic stand based thread reels ( 8 ), wherein the two control magnets ( 10 ) are positioned opposite on the arm wherein the two magnetic stands ( 7 ) are also opposite ( FIGS. 7 and 8 ) positioned exactly on top of the control magnets ( 10 ).
[0072] In another aspect of the method of the present invention, the fixed thread reel ( 2 ) moves with the platform ( 1 A) ( FIG. 8B ), wherein the fixed thread reel ( 8 ) moves along a first path ( 3 ), wherein, after, the fixed thread reel ( 2 ) passes along the first path ( 3 ) at a first point ( 21 ) next to the magnetic stand ( 7 ), the magnetic stand ( 7 ) moves circularly ( 12 ).
[0073] In an additional aspect of the method of the present invention, the control magnet ( 10 ) and the magnetic stand ( 7 ) together have a second displacement movement ( 20 ) ( FIG. 7 ) that follows a second path ( 20 ), wherein, after, the magnetic stand ( 7 ) passes along the second path ( 20 ) at a second point ( 22 ) next to the fixed thread reel ( 2 ), the magnetic stand ( 7 ) moves circularly ( 12 ).
[0074] In one more aspect of the method of the present invention, the fixed thread reel ( 2 ) moves with the platform ( FIG. 8B ), wherein the fixed thread reel ( 2 ) moves along a first path ( 3 ), wherein, after, the fixed thread reel ( 2 ) passes along the first path ( 3 ) at the first point ( 21 ) where the fixed thread reel ( 21 ) is between the two magnetic stands ( 7 ), the magnetic stands move circularly ( 12 ).
[0075] In another aspect of the method of the present invention, the two control magnets ( 10 ) and the two magnetic stands ( 7 ) together have a second displacement movement ( 20 ) that follows a second path ( 20 ), wherein, after, the magnetic stands ( 7 ) pass along the second path ( 20 ) at a second point ( 22 ) next to the fixed thread reel ( 8 ), having passed the fixed thread reel ( 8 ) in between the magnetic stands ( 7 ), the magnetic stands ( 7 ) move circularly ( 12 ).
[0076] Although the description presents preferred embodiments of the present invention, additional changes may be made in the form and disposition of the parts without deviating from the ideas and basic principles encompassed by the claims. | The present invention provides a machine and method wherein there is no physical contact between one or more thread or filaments reels and the element that generates the movement of said reel or reels in such a way that the thread or filament provided by said reel or reels can form a braid. The element that generates the movement of the reel or reels have a magnetic constituent, wherein the magnetic constituent remotely pulls into moving the device or devices holding the reel or reels. | 3 |
BACKGROUND OF THE INVENTION
The present invention relates to a fuel injection pump for an internal combustion engine. U.S. Pat. No. 3,006,556 discloses an injection pump comprising a locking mechanism which holds a drive rod for a pump piston on the injection pump and prevents it from being lost when the injection pump is separated from a mechanical drive element such as a driving cam, for example, during servicing. This arrangement also prevents a restoring spring which also acts on the pump piston via the drive route from accidently pulling the piston out of its cylinder. This safety mechanism comprises a bolt with a molded locking lug within a bore extending transversely through the drive route. The locking lug engages in a slot-shaped recess which is located in a rod guide tube embracing the drive rod. The spring which is also disposed in the bore extending at right angles to the drive route keeps the locking lug in the slot-shaped recess. Both the bolt and the spring are prevented from being accidently released from the bore by means of a locking ring or locking disc. By reason of the fact that this safety mechanism consists of a number of parts it is costly to produce and difficult to assemble. Furthermore, the flat-shaped recess prevents the drive rod from rotating freely because it runs essentially parallel to the longitudinal access of the drive rod.
U.S. Pat. No. 2,819,657 discloses an injection pump in which a locking bolt is inserted in a recess bored transversely in a stationary guide tube and penetrates a slot extending in the longitudinal direction of a coupling sleeve surrounding the drive rod. The bolt has a complicated shape and is therefore costly and during assembly its pin-shaped end must be inserted first into the opening. This safety mechanism also prevents free rotation of the drive rod.
ADVANTAGES OF THE INVENTION
The injection pump revealed in the specification and finally claimed herein is inexpensive and because the locking elements is in the form of a bearing it can be assembled using simple means.
The characterizing features of claim 2 allow the drive rod and piston to be rotated about angles of any desired magnitude relative to the pump cylinder. The characterizing feature of claim 3 prevents dent depressions from being produced in the annular groove and thereby eliminates the risk of the drive rod being prevented from rotating freely. According to the feature of claim 4, when the bearing performs its locking function, no auxiliary means are required to keep it in a position in which its locking forces are exerted. The advantage of the embodiments comprising the features according to claims 5 and 6 and claims 5 and 7 is that the bearing is held in its appropriate recesses by existing essential pump components. The refinement claimed in claim 8 has a relatively short coupling sleeve.
The drawings show two embodiments of the invention. Further details of these embodiments are provided in the subsequent description.
The invention will be better understood and further objects and advantages thereof will become more apparent from the ensuing detailed description of preferred embodiments taken in conjunction with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a longitudinal cross sectional view of a first embodiment;
FIG. 2 is a second longitudinal cross sectional view of the embodiment according to FIG. 1.
FIG. 3 is a cross sectional view on line III--III of FIG. 1;
FIG. 4 is a cross sectional view on line IV--IV of FIG. 2; and
FIG. 5 is a longitudinal cross sectional view of a second embodiment.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The injection pump 2 shown in FIGS. 1-4 comprises a pump housing 3, a cylinder 4 inserted in the pump housing 3, a piston 5, a pressure valve 6 disposed beneath the pump cylinder 4, an injection nozzle 7 connected in series with the pressure valve 6 and a mounting sleeve 8 by means of which the injection nozzle 7, the pressure valve 6, and the cylinder 4 are held in the pump housing 3. The injection nozzle 7 corresponds to one disclosed in German Offenlegungsschrift No. 31 11 837. The pressure valve 6 comprises a pressure valve holder 9, a valve body 10 which is displaceable in the valve holder 9 and a closing spring 11. A valve spool 12 passes through the pump cylinder 4 between the pressure valve 6 and the piston 5. The valve spool 12 is longitudinally displaceable in a seal tight manner in a bore 13 extending transversely through the cylinder 4. Another bore 14 which forms a valve seat is disposed in an extension of the bore 13. The valve spool 12 has an annular closed control edge 15 which faces towards the bore 14. A spring support plate 17 is disposed on an end 16 of the valve spool 12; said end 16 projecting away from the bore 14. A spring 18 presses on this spring support plate 17 in the direction of the cylinder 4. The bore 13 is connected with a hydraulic control device (not shown) via a connection nipple 19. This control device is described in German Offenlegungschrift No. 31 11 837. It is used to control injection operations.
A guide conduit 20 is provided on the pump housing 3 and is concentrically disposed with respect to the cylinder 4. A guide sleeve 21 is mounted in a longitudinally displaceable manner in the guide conduit 20. The guide sleeve 21 comprises an outwardly projecting flange 23 on its end projecting from the guide conduit 20. A prestressed restoring spring 24 is inserted between this flange 23 and the housing 3. The end 22 receives a means 25 arranged to receive a drive rod 25 which is not shown said means being prevented from falling out of a locking ring 26. A coupling sleeve 27 is inserted in the guide sleeve 21. This coupling sleeve 27 grips beneath a collar 28 disposed on the piston 5 and thereby holds the piston 5 on the drive rod 25. The coupling sleeve 27 is inserted between the guide sleeve 21 and the drive rod 15 and is thus prevented from axial displacement. A mechanical drive element (not shown) acts on the drive means 25 in the direction of the piston 5. This mechanical drive element may consist, for example, of a push rod which is displaced in a known manner by a cam means driven by an internal combustion engine. The drive means 25 reciprocates the piston 5 within the cylinder 4. As a result, fuel which is sucked into the cylinder 4 via a suction opening 29 is subjected to pressure and depending on the position of the valve spool 12, it either flows back into a supply chamber 30 or it flows through the pressure valve 6 to the injection nozzle 7. A subsequent suction stroke is then produced as a result of the following operations: the restoring spring 24 raises the guide sleeve 21 via the flange 23, moves the drive means 25 towards the drive member and thus moves the piston 5 upwards within the cylinder 4 via the coupling sleeve 27.
The injection pump 2 comprises a locking mechanism 31. It consists of a recess 32 internally provided in the guide conduit 20, of a recess 33 provided in the guide sleeve 21, of a bearing 34 and of the upper end 35 of the pump cylinder 4. The bearing 34 projects both into the recess 32 and also into the recess 33. In the embodiment shown the recess 32 consists of an annular groove. The recess 33 is a slot which extends in the longitudinal direction of the guide sleeve 21. The end 35 of the cylinder 4 holds the bearing 34 in the recess 32. The length of the recess 33 is such that during normal operation of the pump 2 when the pump piston 5 reaches its maximum position at the end of a suction stroke its lower end does not touch the bearing 34. When the injection pump 2 is not mounted in an internal combustion engine the locking mechanism 31 prevents the guide sleeve 21 and thus the piston 5 from falling out of the injection pump 2. The locking mechanism 31 also performs this task during removal of the drive element (not shown) which acts on the drive means 25. The locking mechanism 31 also facilitates assembly of the internal combustion engine after insertion of the injection pump 2.
It is occasionally desirable between the end of one suction stroke and the subsequent pressure stroke of the injection pump to obtain a slight play between the drive means and the drive element acting upon it with the purpose of forming a lubricating film between said elements. In this event, a plurality of recesses 33 can be provided on the guide sleeve 21 and a plurality of bearings 34 can be inserted. When this is the case, the cross sections of the recesses 32 and the low end 36 of the recesses 33 are designed to perform closely to the radii of the bearings 34 to avoid dent depressions in the recesses 32 and 33 as a result of successive stroke limitations by the bearing 34. As a result of this conformity, the locking forces act essentially at acute angles relative to the longitudinal access of the injection pump 2. As a result, the sum of these forces is not substantially greater than the force of the restoring spring 24 and the inert forces of the injection pump components being displaced. A further advantage of adapting the lower ends 36 to the radii of the bearings 34 is that these do not exert disruptive forces on the end 35 of the cylinder 4. The groove 32 can be easily manufactured as a result of its configuration as an annular groove. The annular groove allows the guide sleeve 21 to rotate freely relative to the guide conduit 20. In the event that free rotatability about angles of any size is not required, the recess 32, respectively recesses, need only extend as an are of specific lengths. For example, the recess 32 may be in the form of a blind hole when it is undesirable for the bearing 34 to be displaced in the circumferential direction of the guide conduit 20.
The second embodiment of an injection pump 42 shown in FIG. 5 also comprises a pump housing 43, a cylinder 44, a piston 45, a pressure valve 46, an injection nozzle 47 and a securing sleeve 48. A discharge channel 52 which opens into the cylinder 44 is provided in place of a valve spool 12 extending through the cylinder 4 of the first embodiment. This discharge channel 52 is connected via another channel 53 which crosses the pump housing 43 with a fuel quantity control device 54. This fuel quantity control device is constructed similar to one described in U.S. Pat. No. 3,486,494 or German disclosure document No. 19 07 316. A guide conduit 60 is provided on the injection pump housing 43 concentrically with respect to the cylinder 44. A guide sleeve 61 is disposed in a longitudinally displaceable manner within the guide conduit. On its end 62 which projects from the guide conduit 60 the guide sleeve 61 comprises a radially outwardly directed flange 63. A prestressed restoring spring 64 is inserted between the flange 63 and the housing 43. At its end 62 the guide sleeve 61 receives a means 65 adapted to receive a drive rod. The drive means for the rod is prevented from falling out of a locking ring 66. A coupling sleeve 67 is inserted between the drive rod 65 and the guide sleeve 61. The coupling sleeve 67 grips beneath a collar 68 which is provided on the piston 45. It holds the piston 45 against the support means 65 for the drive rod via the collar 68. The injection pump 42 also comprises a locking mechanism 71. This locking mechanism 71 consists of a first recess 72 in the guide conduit 60, a second recess 73 in the guide sleeve 61 and a bearing 74. As in the first embodiment, the recess 72 can be in the form of an annular groove, an arched groove or a blind hole. The recess 73 is also a slot as in the first embodiment. When the recess 72 is in the form of an annular groove or an arched groove, the recess 73 is preferably disposed in the longitudinal direction of the guide sleeve 61. When the recess 72 is in the form of a blind hole, the slot-shaped recess 73 can be in the form of a course thread groove. The coupling sleeve 67 and the drive means 65 for the rod are longer than those of the first embodiment. The coupling sleeve 67 covers the recess sleeve 73 inwardly over its entire usable length. As a result, the coupling sleeve 67 serves as a lock element which prevents the bearing 74 from being released from the recess 73. The coupling sleeve 67 is equipped with an integral nose 75 to enable it to be as short as possible in spite of its locking function. This nose 75 engages in the recess 73 and prevents the coupling sleeve 77 from being rotated relative to the guide sleeve 61. As a result, the nose 75 prevents a recess 76 which is disposed in the lower end of the coupling sleeve 67 through which the collar 68 of the piston 45 is naturally inserted into the coupling sleeve 67 from coming into alignment with the bearing 74. This form of incorrect alignment would result in the bearing 74 leaving its appointed place both in the recess 72 and also the recess 73. As in the first embodiment the locking mechanism 71 can also be designed in such a way that a slight play is provided from time to time between a drive element (not represented) and the drive rod means 65 which support this play promoting formation of a lubricating film in a specific manner. Once this is the case a plurality of bearing recesses 74 and recesses 73 can be provided as described above.
The foregoing relates to preferred exemplary embodiments of the invention, it being understood that other embodiments and variants thereof are possible within the spirit and scope of the invention, the latter being defined by the appended claims. | The fuel injection pump of this invention proposes at least one cylinder, a piston, a drive rod, a guide sleeve for the drive means, a guide conduit embracing the guide sleeve, a restoring spring for the drive rod and piston, said piston being designed to execute a suction stroke under the influence of the restoring spring. The injection pump also comprises a locking mechanism comprising a bearing which extends into two recesses. The one recess is in the form of an annular groove located in the guide conduit. The other recess is a slot formed in the guide sleeve in its longitudinal direction. The locking mechanism prevents the guide sleeve together with the rod and piston from falling out after the injection pump has been assembled. The locking mechanism is inexpensive and easy to assemble because it requires only a single bearing in addition to already existing components of the injection pump. | 5 |
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a device and method for the removal and/or installation of a vehicular component from a vehicle. In particular, the present invention relates to a such a device and a method for removal, whereby a vehicular component, such as a transmission or differential unit may be removed via the underside of a vehicle.
DESCRIPTION OF THE PRIOR ART
[0002] The removal of vehicular components, such as transmission units and differentials from trucks, tractors, graders, earthmoving and mining equipment, such vehicles typically being quite large in size, is a necessary function for servicing of such components. The removal of such components to date has typically been done by means of cranes and other similar devices to extract the components in a direction substantially upwardly from the vehicle.
[0003] This not only requires specialised equipment, but is also somewhat dangerous in that persons are required to work at elevated positions. In recent times in Australia, the requirement of workers to work at such elevated positions have come to issue with regulatory occupational health and safety authorities, which authorities now require the use of harnesses, railings, etc., to ensure the improved safety of such workers. Consequently, the expense of utilising such equipment for the removal of the vehicular components from the vehicles for servicing and the like, has been even further increased.
SUMMARY OF THE INVENTION
[0004] The present invention seeks to provide a device and method for the removal and/or installation of a vehicular component, such as a differential or transmission unit, from a vehicle, whereby, by use of the device and method of the present invention, the component is manocuvred underneath the vehicle.
[0005] In one broad form, the present invention provides a device for removal/installation of a vehicular component from a vehicle, said device including:
[0006] trolley means, for movement of said device over a substrate surface;
[0007] actuation means, a first end of which is attached to said trolley means, and, a second end of which is adapted to be connected to said vehicular component;
[0008] whereby, when said vehicular component is attached to said second end of said actuation means, said vehicular component is manoeuvred between an installed position where said vehicular component is installed on said vehicle, and, an uninstalled position where said vehicular component is provided substantially on said trolley means for movement below said vehicle.
[0009] Preferably, said vehicle is a truck, tractor, earthmoving or mining equipment, and, said vehicular component is a differential, transmission unit or other vehicular component.
[0010] Also preferably, said actuation means includes a pair of articulated arms, one on substantially each side of said trolley means.
[0011] In its preferred form, each of said arms includes a plurality of pivotally connected arm members.
[0012] Preferably, each said member is movable by means of an actuator, such as a hydraulic cylinder, a motor or other actuator.
[0013] Also preferably, said second end of said actuation means is adapted to be connected to said vehicular component in a removable manner, such as means of any one or combination of bolt(s), screw(s), a clamp(s), or other removable means.
[0014] In a preferred embodiment, said second end of said actuation means is adapted to be connected to said vehicular component in a removable manner to said vehicular component by means of a saddle device.
[0015] In this preferred form, preferably, said vehicular component is a transmission unit whereby said saddle device includes a pair of spaced apart saddle components adapted to surround said transmission unit and be bolted or otherwise attached to flanges provided therearound.
[0016] In another preferred embodiment, said second end of said actuation means is adapted to be connected to a differential unit by means of an adaptor of complementary shape and be adapted thereto by any one or combination of bolt(s), screw(s), clamp(s).
[0017] In a preferred embodiment of the invention, said trolley is substantially elongated and lowstrung in shape, and is provided with wheels, rollers or the like for the movement thereof over the substrate surface.
[0018] In a further broad form, the present invention provides a method of removing a vehicular component from a vehicle using the device as hereinbefore defined, said method including the steps of:
[0019] providing said trolley means into a position substantially below said vehicular component;
[0020] operating said actuation means such that said second end thereof is positioned substantially proximal to said vehicular component;
[0021] attaching said second end of said actuation means to said vehicular component, for example, by bolts, screws, clamps and/or the like;
[0022] removing said vehicular component from said vehicle, by operating said actuation means to manoeuvre said vehicle component to a position substantially onto said trolley means; and,
[0023] removing said trolley means, with said vehicular component, from underneath said vehicle.
[0024] In a further broad form, the present invention provides a method of installing a vehicular component from a vehicle using the device as hereinbefore described, said method including the steps as hereinbefore recited but performed in the reverse order.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] The present invention will become more filly understood from the following detailed description of a preferred but non-limiting embodiment thereof, described in connection with the accompanying drawings, wherein:
[0026] [0026]FIG. 1 illustrates an isometric view of a device in accordance with the present invention, supporting a transmission unit;
[0027] [0027]FIG. 2 illustrates, in FIGS. 2 ( a ), 2 ( b ) and 2 ( c ) thereof, various views of the transmission unit,
[0028] FIGS. 2 ( a ) and 2 ( b ) illustrating alternative isometric views, whilst, FIG. 2( c ) illustrating an elevational view of the transmission unit;
[0029] [0029]FIG. 3, in FIGS. 3 ( a ), 3 ( b ) and 3 ( c ), illustrate a “saddle” which may be utilised in the device of FIG. 1 to support the transmission unit shown in FIG. 2, FIGS. 3 ( a ) and 3 ( b ) illustrating alternative isometric views of the saddle, and, FIG. 3( c ) illustrating an elevational view thereof,
[0030] [0030]FIG. 4 illustrates the various steps by which a transmission unit may be extracted from the vehicle utilising the device of the present invention;
[0031] [0031]FIG. 5 illustrates how a differential unit may also be extracted utilising the device in accordance with the present invention; and,
[0032] [0032]FIG. 6 illustrates, in FIGS. 6 ( a ) and 6 ( b ), isometric and plan vies of an alternative embodiment of a device in accordance with the present invention, similar to that shown in FIG. 1, but without the vehicular components attached.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0033] Throughout the drawings, like numerals will be used to identify similar features, except where expressly otherwise indicated.
[0034] As shown in FIG. 1, the device for removal and/or installation of a vehicular component from a vehicle, is generally referenced by numeral 1 , and includes a trolley means 2 , supporting an actuation means 3 .
[0035] The trolley is embodied as a substantially elongate device having wheels or rollers at a first end 4 thereof, and also at a second end 5 thereof (not shown). The trolley is therefore formed of a substantially elongate lowstrung frame member which is adapted for travel over a substrate surface. The travel of the trolley may either be performed manually, i.e. by being pushed, or, it may be motorised. Appropriate controls 6 may be provided at a convenient location to be activated by an operator. In a preferred form, at least one of the sets of wheels or rollers provided at one end of the trolley is pivotal, for steering movement of the trolley, as desired, for optimal positioning of the trolley. This is illustrated in the embodiment of FIG. 6, where the front wheels 4 are pivoted at pivots 36 , being actuated by steering actuator 37 .
[0036] The actuation means 3 includes a first end thereof 7 , which is adapted to be connected to the trolley means 2 , and, a second end thereof 8 which is adapted to be connected to the vehicular component. The vehicular component illustrated in FIG. 1 is a transmission unit 9 . Further views of the transmission unit 9 are illustrated in FIG. 2, where it can be seen that the transmission unit 9 includes a main body portion 10 having a pair of flanges 11 and 12 at opposed ends thereof, each of which are typically provided with a plurality of bolt holes 13 .
[0037] The mode by which the transmission unit may be attached to the second end 8 of the device 1 in accordance with the present invention may be via a variety of attachment mechanisms. A suitable attachment mechanism or ‘saddle’ 14 is shown in FIG. 3, wherein FIGS. 3 ( a ) and 3 ( b ) illustrate alternative isometric views thereof, and, FIG. 3( c ) illustrates an elevational view thereof. The attachment mechanism illustrated in FIG. 3, embodied in the form of a saddle device 14 has a pair of saddle arms 15 and 16 connected via an intermediate portions 17 . As will be appreciated, the saddle device 14 is adapted to effectively straddle the underside of the transmission unit 9 and support same thereby. Firstly, the guide sleeves 15 a and 16 a are bolted to the flanges 11 and 12 respectively via bolt holes 13 . As will be seen, each of the guide sleeves 15 a and 16 a includes a guide channel 38 which are adapted to locate and receive rollers 19 as the saddle 14 (attached to the device 1 ) is brought into engagement with the transmission unit 9 . This, of course, greatly simplifies the attachment of the transmission unit 9 to the device 1 by effectively performing a self-centering function. Without this, alignment of the attachment means of the device 1 to the transmission unit 9 would be considerably more complex and tedious requiring precise alignment of bolt holes or the like for insertion of bolts therethrough.
[0038] A variety of rollers, including axial constraint rollers 18 and lateral constraint rollers 19 may be provided to permit rotation of the transmission whilst it is supported thereby. Appropriate engagement means, such as illustrated by reference numeral 20 may be provided to abut the flanges 11 and 12 , and for connection of the transmission unit to the saddle thereby, by provision of suitable bolts or the like device through bolt holes 21 and 13 (on flanges 11 and 12 ).
[0039] The manner by which the transmission unit may be manoeuvred from its installed position on the vehicle to a position remote from the vehicle, whereat it may be serviced or the like, is illustrated in FIG. 4. As will be appreciated, the vehicle has various components such as cross-member 22 and differential housing 23 , past which the transmission unit 9 must be manoeuvred from the installed position to the position substantially on the trolley 2 , such as illustrated in the various representations shown in FIG. 4.
[0040] This manoeuvring is basically performed by selective movement of the various articulated arm members which combine to form the actuation means. The illustrated embodiments shows that the actuation means includes a pair of articulated arms 24 and 25 on opposed sides of the trolley 2 (see FIG. 1). Each articulated arm is shown to include a plurality of pivotally connected arm members. For example, arm 24 includes a first arm member 26 and a second arm member 27 connected by pivot 28 . Arm member 26 is attached via pivot 29 to support 30 , which itself is attached to trolley means 2 . A further pivot point 34 enables further pivotal movement of the device by operation of cylinder 33 . Hydraulic cylinders, or other actuating means, such as motors, may be then operated to provide the appropriate pivotal activation of arms 27 and 28 , such that they may be used to manoeuvre the transmission unit 9 from its installed position on to the trolley means 2 , such as shown in FIG. 4. Appropriate hydraulic cylinders 31 , 32 and 33 are illustrated in FIG. 1 for this purpose. FIG. 4 also illustrates the basic lifting parallelogram which enables such functional movement, the movement being achieved by extension of the lift ram 31 , and, the tilt ram 32 being extended to control the relative movement of arms 26 and 27 .
[0041] It will therefore be appreciated that by appropriate movement of the arms via the hydraulic cylinders or the like, the vehicular component, being the transmission shown in FIG. 4, may be removed from a vehicle by means of firstly providing a trolley in to a position substantially below the vehicular component, operating the actuation means such that the second end thereof is positioned substantially proximal to the vehicular component, in this case the transmission, attaching the second end of the actuation means to the vehicular component by bolts, screws, clamps and/or the like, and then removing the vehicular component from the vehicle by sequentially or simultaneously operating the actuation means to manoeuvre the vehicular component to a position substantially onto the trolley, and then, being able to remove the trolley from underneath the vehicle, such that the transmission may be then serviced.
[0042] Likewise, the method of installing the transmission is performed by carrying out those steps in the opposite order.
[0043] [0043]FIG. 5 illustrates an alternative preferred embodiment of the invention, in this case, the device is utilised to install or remove a different vehicular component, in this case, the differential unit. Instead of attaching the saddle 14 shown in FIG. 3, the second end of the actuation means is provided with an alternative attachment for removable securement on to the differential, as shown. The differential may then be moved out of the differential housing, and likewise, with appropriate tilting and manoeuvring of the arms and the trolley, the differential unit may be extracted from the vehicle for servicing.
[0044] It will be appreciated by persons skilled in the art that, whilst a particular embodiment of the device is illustrated, utilising a trolley and an actuation means, numerous variations and modifications may be made to such a device whilst still performing the function of the device, that is, the extraction of vehicular components from vehicles in a position substantially underneath the vehicle.
[0045] It will also be appreciated that whilst the installation of and removal of a transmission unit and differential are described hereinbefore, that other vehicular components may likewise be removed or installed from vehicles by appropriate attachment of those components to the second end of the actuation means, in a similar manner, and as such should also be considered to fall within the spirit of this invention.
[0046] These and all other variations and modifications to the present invention which become obvious to persons skilled in the art, and which enable the function of the device embodied by the present invention to still be effectively performed, should be considered to fall within the scope of the invention as broadly hereinbefore described and as hereinafter claimed. | A device and method for removing or installing a vehicular component, such as a transmission or differential, from a vehicle. The device ( 1 ) includes a trolley ( 2 ) having an actuation means ( 3 ) thereon. A saddle like device ( 14 ) is engaged with the vehicular component ( 9 ), the saddle ( 14 ) utilizing a self-aligning guide channel ( 38 ) and roller ( 19 ) locating and engaging system. Once attached, the vehicular component ( 9 ) may be uniquely manoeuvred via the underside of the vehicle, effected by a pair of articulated arms ( 24 ) and ( 25 ) operated by a plurality of hydraulic cylinders ( 31 ) and ( 32 ) to achieve the required movement of the arms ( 24 ) and ( 25 ). The trolley may then be moved from under the vehicle, such that the transmission, differential or other vehicular component may then be easily accessed for servicing. | 8 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a rotary capping apparatus for applying a screw-on type cap to a filled container and, more particularly, to a rotary capping apparatus having an integrated feedback control system to precisely regulate the torque applied to such a container.
2. Description of Related Prior Art
Rotary capping devices are commonly used in industrial container filling operations such as pharmaceuticals wherein containers are filled with liquid or powder and then capped. In such filling operations empty containers are initially placed in so-called unscrambling devices, which are advanced to a filling line for filling, and then carried to the capping station via conveyor belts, starwheel devices and other apparatus for capping.
The screw-on type caps are disposed in unscrambling devices and then fed to the capping apparatus by way of conveyors and/or vibratory guides. Next, the caps are placed on the containers by a so-called pick-and-place mechanism. At the torquing station, the capping apparatus clamps the filled containers and grips the caps pre-positioned on the containers and rotates the caps onto the container. After a predetermined torque is applied by an adjustable chuck, the torquing operation is completed and the installed cap is released. The container clamping means is then released and the container is moved away from the capping apparatus by a suitable conveying means, for example, the belt or starwheel device that initially brought the container to the capping apparatus.
The containers capped by such a rotary capping apparatus must be subsequently unscrewed by hand to permit dispensing of the contents. Thus, the caps must be applied with sufficient torquing force so as not to leak during storage and transportation to the consumer, but may not be so tightly applied as to make it difficult for the consumer to remove the cap using only finger force. Consequently, the amount of torque applied must be within predetermined limits.
The prior art shows numerous patents in the field of capping devices for controlling the torque applied to such screw-on caps for containers. Most of the devices shown in the prior art use spring or air actuated friction slip clutches. In recent years, magnetic clutches or magnetic drives have also been frequently employed to control the torque applied to the caps.
Some examples of rotary capping devices in the prior art which utilize a disk clutch in the capping chuck are described in U.S. Pat. Nos. 4,558,554, 5,148,652 and 5,983,596. These disk clutches are comprised of a number of friction plates stacked together. The amount of torque applied on the caps is controlled by a mechanical adjustment of the pressure in the friction plates. Once the desired torque is applied, the friction clutch will slip and interrupt the connection with the actuating means. At this point the gripping means are gradually opened to disengage from the cap and to allow the next container to be fed into the device, and the application head is lifted away from the container to allow the next container to be fed into the device. The disk clutches can also be actuated by pressure from a compressed air source. These clutches are known as air clutches and permit more accurate control of the pressure on the friction plates through an air pressure regulator and an air pressure gauge. In such air clutches an air piston is carried in the underside of an air clutch hub between a pair of piston seals and a retaining ring. The air clutch mechanism senses the applied torque between the cap and neck of a container and will allow the cap tightening discs thereon to stop once the desired torque is reached. The air pressure regulator can vary the air pressure to the air clutch piston to change the tension on the friction plate assembly thereby varying the torque setting.
Some examples of the use of magnetic clutches in the prior art are described in U.S. Pat. Nos. 5,197,258 and 5,437,139. In these patents, a pair of axially aligned circular cylinders is provided. Each of the cylinders is provided with cavities containing magnets. The maximum torque provided by the clutch is controlled by the vertical distance between the two disks through removable spacer disks of varying thickness. By providing a greater number of spacer disks, finer adjustment in torque values can be achieved.
The cap gripping mechanisms of the prior art are indeed diverse. Perhaps the most common mechanism is a tapered insert inside an aperture for engagement with caps of different sizes as exemplified in U.S. Pat. No. 5,148,652. Another common device is the use of two or three gripping jaws as disclosed in U.S. Pat. Nos. 4,232,499 and 5,983,596. The capping chucks in these patents have retaining jaws that are adapted to receive and support a cap and to cooperate with an internal torque release lever and torsion spring arrangement operative to release the jaws from the cap after a predetermined rotational torque is applied between the cap and a container.
Still another cap gripping mechanism is disclosed in U.S. Pat. No. 5,459,975. The chuck disclosed in this patent has a plate that provides a seat for a flat elastomeric ring, which constrains the ring against radial expansion. The elastomeric ring defines an opening to accommodate the cap to be tested. The housing further accommodates a so-called pusher member, which normally engages the elastomeric ring. A cam applies a force to move the pusher member against the elastomeric ring and this force coacts with the constraining force of the annular plate to cause the elastomeric ring to expand inwardly into tight gripping engagement with a cap disposed within the elastomeric ring permitting torque to be applied to the cap by rotation of the chuck without deforming the cap.
Although the methods and apparatus for capping containers described hereinabove are effective, the capping devices of the prior art have inherent limitations, which require further improvement. Due to the difficulty in making adjustments to the torque exerted during the cap-tightening process, the prior art mechanisms for tightening caps onto containers have resulted in leaking containers requiring time consuming and expensive reprocessing. Also the mechanisms for gripping such screw-on caps frequently damage the caps due to the use of excessive and/or non-uniform gripping forces. If too much compression force is applied to the cap, it may be damaged or deformed resulting in faulty application of torque, or the cap may bind and not screw onto the container properly causing the containers to be rejected.
The cap gripping mechanisms of the prior art need improvement for the following additional reasons. Such cap gripping mechanisms of the prior art often employ gripping jaws, which are mechanically complex, expensive, difficult to adjust for individual cap sizes and shapes or which are custom made for each different cap size and shape. Such mechanically complex gripping mechanisms also introduce potential operator error into the capping process requiring complicated adjustments and resultant time losses during production set-up for different products. In addition, such mechanical gripping jaws require manual set-up and do not provide for computer-controlled adjustment to different cap sizes. Additionally, prior art capping devices have generally been configured such that when chuck jaws have to be repaired or replaced, either due to changes in the sizes of the caps and/or containers being processed or due to damage to the jaws in use, extensive delays are encountered while the capping apparatus is disassembled to allow the chucking jaws to be serviced.
Prior art cap gripping mechanisms that utilize a tapered aperture for engagement with caps depend on frictional engagement between the aperture and the contact area of the cap. It is well known that friction is an unstable parameter and that the friction coefficient varies significantly with ambient conditions and the shape of contact surfaces often causing slippage. This slippage is more likely to occur when there is a relatively small contact area between the cap and tapered aperture of the gripping device. Such slippage will cause rapid wear of the gripping device having a detrimental effect on gripping performance as well. In addition, the fixed size of such tapered-aperture gripping mechanisms does not allow for computer-programmable changeover for different cap sizes.
Prior art gripping mechanisms utilizing an elastomeric ring that expands inwardly into tight gripping engagement with the cap have the inherent disadvantage of wearing relatively quickly because the elastomeric ring deforms all of its volume and still has a limited contact area with the cap. Also, different cap sizes and shapes require manual change over to different tooling. In addition, such cap gripping mechanisms do not allow for computer-programmable adjustment for different cap sizes.
Prior art torquing mechanisms having a disk clutch in the chucking device have the disadvantage of not utilizing any feedback in compensating significant errors affecting the capping torque. Large variations in such error is due to friction fluctuation in clutch disks due to changes in ambient conditions, especially temperature rising during the slippage, and wearing of slipping surfaces. Any required changeover to different torque settings will require numerous set-up samples and many adjustments and may still result in unstable torque. In addition, the disk clutch type torque mechanism does not allow for computer-adjustable torque over a large torque range.
Other prior art torquing mechanisms utilizing magnetic clutches in the capping chuck have the disadvantage of lacking any feedback in compensating for significant error affecting the capping torque. In such torquing mechanisms any changeover to different torque requires manual exchange of so-called spacer disks for varying the magnetic force. In addition, such magnetic clutch torquing mechanisms do not provide for computer-controlled adjustment of torquing changes over the entire torquing range.
SUMMARY OF THE INVENTION
Accordingly, the present invention is a rotary capping apparatus and feedback control system for regulating the torque applied to screw-on type caps for industrial containers such as pharmaceutical containers. The present capping apparatus and feedback control system is integrated into a machine suitable for so-called clean room production, which provides for automated, sterile processing of such caps and containers. In the present invention such caps are gripped by an inflatable chucking device actuated by compressed air including an elastomeric insert that grasps the entire surface of the cap and not just a few contact points about a top edge of the cap as in prior art devices. Thus, in the present apparatus the pressure applied via the inflatable chucking device can be minimal. This significantly increases the life of the tooling and the stability of performance, reduces pressure on the periphery of the cap, and also prevents deformation of the cap.
The present capping apparatus also provides for positive gripping, that is, undesired slippage or slippage as a means of metering the torque is totally eliminated. The gripping force is sufficient to prevent any slippage between the cap and the inflatable chucking device. The minimum required gripping force can be varied for different caps and can be adjusted by a computer-programmable pressure regulator thereby providing programmable changeover for different applications. This eliminates operator involvement and associated human error and reduces production down time by allowing immediate changeover by selection of new parameters from a computer console. The gripping force is released by purging (or vacuuming for increased speed) the pressurized air from the inflatable elastomeric insert surrounding the cap.
The present invention is also able to control torque more accurately by the use of a closed loop feedback control system including a servomechanism to control the applied torque. In the present feedback system a comparison between the actual process condition and the desired condition is made. The difference between these two signals (i.e. the error) is fed into the control system, which uses this information to alter the output signal to attain the required torque value calculated as: Error signal=set point−measured value. More specifically, in this application the actual torque being applied on the caps can be continuously fed back into the system for further action until the desired torque applied on the caps is reached. The present apparatus uses a proportional, integral and derivative known as a (PID) control system to control the applied torque for purposes of this invention. Such a PID control system consists of the following major components: a central processing unit (CPU), an input section, and output section, a power supply and a computer program.
The torque in the present capping apparatus is applied to the cap via a computer (CPU) controlled servomechanism. The servomechanism is engaged with the inflatable chucking device and executes closed loop PID control with position feedback, which results in precise torque application. Moreover, the value of the applied torque is adjustable from the computer console allowing for immediate changeover to different products, and eliminates any operator error associated with mechanical adjustments. The driver of the servomechanism is a servomotor. When the desired torque value is reached, the CPU immediately interrupts the PID controlling loop and removes voltage from the servomotor.
This system represents a significant improvement over the prior art capping devices described hereinabove wherein so-called open-loop control is used. In such devices no information is fed back to the system to determine whether the desired output was achieved and consequently a large error in the desired applied torque may result. Many outside influences affect the operation of such prior art capping devices. For example, the friction coefficient varies significantly with ambient conditions and shape of the cap engaging surfaces often causing slippage. Such slippage is more likely to occur due to a relatively small contact area between the cap and tapered aperture of the gripping chuck. Such slippage will often cause rapid wear of the gripping chuck and will generate heat. Both the resultant wear of the gripping chuck and the heat generated adversely impact the accuracy of the applied torque.
The present rotary capping apparatus also features automatic secondary height adjustment functions such that the machine will automatically set the vertical height of the cap dispensing mechanism based on a computer program for a specific product selected. This function is carried out manually in the prior art devices.
Other features and technical advantages of the present invention will become apparent from a study of the following description and the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
The novel features of the present invention are set forth in the appended claims. The invention itself, however, as well as other features and advantages thereof will be best understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying figures, wherein:
FIG. 1 is a cutaway perspective view of a rotary capping apparatus in accordance with the present invention;
FIG. 2 is a perspective view of the inflatable chuck insert of the present invention;
FIG. 3 is a perspective view of a cylindrical air tube component utilized in conjunction with the inflatable chuck insert of FIG. 2;
FIG. 4 is a cross-sectional view taken through the cap driver assembly of the present invention showing the components thereof;
FIG. 5 is an orthogonal view of the gear mechanism within the capping head of the present invention;
FIG. 6 is a plan view of the gear mechanism within the capping head of the present invention;
FIG. 7A is a cross-sectional view taken through the capping head along line A—A of FIG. 6;
FIG. 7B is a cross-sectional view taken through the capping head along line B—B of FIG. 6 showing the inflatable chuck in a deflated condition;
FIG. 7 B′ is also a cross-sectional view taken through the capping head along line B—B of FIG. 6 showing the inflatable chuck in an inflated condition;
FIG. 8A is a side elevational view of the actuating mechanism for the present capping apparatus showing the capping head in the raised position;
FIG. 8B is a side elevational view of the actuating mechanism for the present capping apparatus showing the capping head in the lowered position;
FIG. 8C is a side elevational view of the actuating mechanism for the present capping apparatus with the container and cap removed to show the vertical movement of the capping head by the drive carrier shaft and the air/vacuum channel shaft;
FIG. 9 is a perspective view of the spline mechanism of the present mechanism connecting the servomotor to a drive shaft;
FIG. 10 is a schematic representation of the operation of the present rotary capping apparatus;
FIG. 11A is a graphical representation showing the theoretical position of the cap driver assembly generated by the servomotor as a function of time, (t);
FIG. 11B is a graphical representation of the actual position of the cap driver assembly generated by the servomotor as a function of time, (t);
FIG. 11C is a graphical representation showing the position error, which is the difference between the theoretical position and the actual position;
FIG. 11D is a graphical representation showing the torque as a function of time, (t);
FIG. 12 is a diagrammatic representation showing the sequence of actions in the present capping process as a function of time, (t);
FIG. 13 is a schematic representation depicting the vertical height adjustment function of the present rotary capping apparatus;
FIG. 14 is an orthogonal view the present rotary capping apparatus showing the components thereof which effectuate vertical height adjustment with various other components deleted for clarification purposes; and
FIG. 15 is a schematic representation depicting the vertical height adjustment function of the secondary supporting frame.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
With further reference to the drawings there is shown therein a rotary capping apparatus in accordance with the present invention, indicated generally at 10 and illustrated in FIG. 1 . The rotary capping apparatus 10 includes a cap placement station, indicated generally at 44 , a cap torquing station, indicated generally at 45 , and an optional filling station, indicated generally at 41 . The present capping apparatus 10 may further include a transparent safety shield (not shown) affixed thereto so as to extend downwardly over the cap driver assembly 401 to protect the operator of the device. It will be appreciated by those skilled in the art that the cap placement station 44 , cap feeder bowl 22 , and optional filling station 41 are all of conventional design.
The capping apparatus 10 further comprises a frame structure shown generally at 31 , comprising a plurality of vertical frame members 32 , 33 , 34 , 35 . The frame structure includes two horizontal plates, namely a bottom plate 37 and a top plate 38 that are fixedly attached to the vertical frame members 32 - 35 , which extend therebetween. It will be noted that members 33 and 34 are partially cutaway in FIG. 1 to show the interior of the present apparatus. Four adjustable legs 851 , 852 , 853 , and 854 (not shown) are attached to the bottom plate 37 to support the structure and provide for height adjustment, which is accomplished by turning the corresponding foot of each respective leg 851 - 854 in a known manner. The present capping apparatus 10 also includes sheet metal side covers (not shown) which enclose the frame structure.
A vibratory feeder bowl or unscrambling device 22 is fixedly secured to a feeder bowl base 39 , which is enclosed by a sheet metal cover 97 . The feeder bowl base 39 is separately supported by legs 855 , 856 , 857 (not shown), and 858 (not shown). The feeder bowl 22 functions to receive and dispense caps 40 therefrom for installation on containers 11 . The feeder bowl 22 orients the caps 40 and discharges them in series with their threaded ends down into a transfer track 23 . Caps 40 are transported from the bowl 22 onto the transfer track 23 via the feeder track 99 . A small gap exists between the feeder track 99 and the transfer track 23 such that vibrations from the feeder bowl 22 are not transmitted to the transfer track 23 .
The transfer track 23 is mounted on track support plate 80 , which in turn is supported by shafts 81 and 82 as more clearly shown in FIG. 14 . Once a product is selected for processing, the present system will automatically move the transfer track 23 to the correct vertical height required to process the product selection. Shafts 81 and 82 are attached to carrier plate 36 and provide for automatic adjustment of the height of the transfer track 23 as described hereinafter in further detail.
It will be appreciated that transfer track 23 has an inlet portion aligned with the outlet portion 22 a of the feeder bowl 22 . The caps 40 are discharged into track 23 with their threaded ends face down. A track cover (not shown) is mounted on the track 23 to keep the caps from stacking on top of one another. The caps 40 move along the track 23 in the direction indicated by the directional arrow 24 in FIG. 1 . The end of the track 23 is disposed adjacent to the cap placement station 44 .
The cap placement station 44 is reciprocated up and down by a shaft 46 , which is positioned within a bearing (not shown) located in the top plate 38 . The shaft 46 is driven pneumatically by an air cylinder mounted on carrier plate 36 . A drive motor 49 is mechanically coupled to shaft 46 by a bracket 66 . A plunger 25 is connected to drive motor 49 and rotated in timed relationship to the capping apparatus cycle. A conventional belt and pulley system (not shown) is used to vary the speed of the motor 49 .
The outlet end of the transfer track 23 is provided with a cap retaining means (not shown), which prevents the leading cap 40 from falling off the track 23 . For example, the cap retaining means can be a spring-biased pair of levers or a rubber gasket with cutouts that will open up when downward force is applied to a cap 40 . Adjacent to the cap retaining means there is also provided an optical sensor (not shown) to detect the presence of a cap 40 ready for cap placement and to send a signal to a computer integrated with the present apparatus. The caps 40 slide with their open, threaded ends down by gravity or under the urging of vibratory pulses or other suitable means. Typically the container caps 40 applied by the capping apparatus 10 have an internal right-handed thread formed therein and adapted for threaded cooperation with a mating external thread formed on the upper neck of the containers 11 . In operation, plunger 25 pushes the leading cap 40 onto the containers 11 . The caps 40 are loosely applied at this stage and may be partially threaded onto the necks of the containers 11 .
The optional filling station 41 includes a fluid discharge nozzle 42 , tubing 43 , and bracket 56 to hold the discharge nozzle 42 . The remainder of the filling mechanism is of conventional design and is not shown. The tubing 43 carries the fluid from a pumping means (not shown) in the filling mechanism to the discharge nozzle 42 , which is mounted on bracket 56 as shown.
The present rotary capping apparatus 10 includes a drive mechanism and associated electronic circuitry and controls that drive and rotate a starwheel 16 that indexes the containers 11 one step at a time as they are filled, capped and torqued. The containers 11 are supported by a bottle support plate 75 , which is fixedly mounted on a plurality of blocks 76 on the plate 38 . Appropriate optical sensors (not shown) are positioned in the capping apparatus 10 to indicate the presence of containers 11 at the start of each cycle.
In operation, a plurality of containers 11 having external threads adjacent the top opening thereof are sequentially transported via conveyor system 14 for pick-up at the entry slot 58 of the starwheel 16 . Once all the stations of the capping apparatus 10 have a container 11 in position, the production operation can start. During the production operation of the capping apparatus 10 , the filling, capping and torquing stations all operate simultaneously. Once all the stations have completed their function, the starwheel 16 is indexed and the containers 11 advance one position. A new container will enter the entry slot 58 and a torqued container will exit from the exit slot 59 . The conveyor system 14 is driven in the direction indicated by directional arrow 65 using known driving means (not shown). Optical sensors (not shown) are used to sense the location of the containers 11 . These optical sensors transmit signals via electrical circuits (not shown) that interrupt the operation of the capping apparatus 10 in the event of a malfunction of the equipment. The actuation and deactuation of the various pneumatic cylinders and electrical motors utilized in the present device are controlled by a central processing unit (CPU) that is installed in the control cabinet 29 .
At the filling station 42 the containers 11 are filled; at the cap placement station 44 a cap is placed and partially threaded onto the neck of a container 11 ; and at the torquing station the cap 40 is fully threaded to a predetermined torque. When the filled and partially capped containers 11 arrive at the torquing station 45 , a clamping block 17 holds the containers 11 in position. The clamping block 17 is operated by a pneumatic cylinder 18 , which is actuated via an electrovalve (not shown). The pneumatic line and associated electronics to extend and retract the clamping cylinder 18 are omitted for purposes of clarity in FIG. 1 .
During the torquing operation the loosely capped containers 11 are held securely at the torquing station against the starwheel 16 . A clamping block 17 mechanically coupled to a pneumatic cylinder 18 is free to move forward and backward to clamp and release the containers 11 . The pneumatic line and associated electronics to extend and retract the clamping cylinder 18 are also omitted for clarity. The clamping block 17 is shown in its extended position in FIG. 1 . Clamping the containers 11 in this position prevents them from rotating when caps 40 are being torqued on to seal the containers. The clamping force with which the containers 11 are secured is adjustable by a compressed air regulator and gauge (not shown) so as to apply only sufficient force to hold the containers 11 against rotation under the applied torque and not so high as to damage the containers.
Once a container 11 at the torquing station 45 has been torqued to the desired setting, the clamping block 17 will retract to permit the starwheel 16 to index the next set of containers 11 . The starwheel 16 rotates in a clockwise direction as viewed from the top as shown by directional arrow 48 . A semicircular starwheel guide 15 is disposed to the outside of the starwheel 16 . The starwheel guide 15 and the starwheel 16 are configured and dimensioned such that there is a loose fit of the containers 11 and there is minimal friction between the containers 11 and the guide 15 during operation. The starwheel guide 15 does not extend 360° as it has a section removed to allow incoming containers 11 to enter and outgoing containers 11 to exit. Guide rails (not shown) serve to guide the containers 11 into and out of the starwheel 16 . With each closing of the clamping block 17 , a new container torquing cycle is initiated by the present capping apparatus 10 as described hereinafter in further detail.
Referring now to the torquing station 45 , its operation will now be considered in detail. Prior to starting the torquing operation, the capping head 12 is moved to its optimal vertical position by the movement of horizontal carriage plate 36 . Such optimal vertical position is determined by the height of the container 11 to be torqued. The horizontal carriage plate 36 serves as a base for all the mechanisms that must be adjusted for variations in container height. In particular, the servomechanism which drives the cap driver assembly 401 is attached to the horizontal carriage plate 36 .
The vertical height adjustment motor 68 is mounted on horizontal plate 36 . Motor 68 controls the height of the capping head 12 by the rotation of shaft 72 , which is transmitted to lead screw 70 by way of belt and pulley system 69 . The lead screw 70 is mounted on plate 37 by bearing 78 such that it is free to turn, but may not move in the vertical direction. A lead nut 89 is attached to the carrier plate 36 and engages the lead screw 70 . When the lead screw 70 is turned the lead nut 89 causes carriage plate 36 to move up and down, which in turn moves the capping head 12 vertically. Vertical shafts 61 , 62 , 63 and 64 extend between and are coupled to bottom plate 37 and top plate 38 by a collar on each end of the respective shafts. Collars 90 , 91 , and 92 are shown in FIG. 1 . Four linear bearings (only three of which are shown namely 94 , 96 , and 97 ) are disposed on plate 36 to engage and move plate 36 up and down the vertical shafts 61 - 64 .
Leadscrew 70 is supported by bottom bearing 78 and top bearing 77 as most clearly shown in FIG. 14 . An ultrasonic transmitter 79 capable of measuring the distance to the carriage plate 36 is disposed on support plate 37 as also seen in FIG. 14 .
Referring again to FIG. 1, the capping head 12 is supported by vertical hollow shafts 5 and 6 . Each of the vertical hollow shafts 5 and 6 can move vertically inside linear bearing blocks (not shown) that are fixedly attached to horizontal plate 38 . The outer portion of the shafts 5 and 6 serve as bearing races sliding up and down in the bearing blocks. On the bottom portion, the vertically parallel, hollow shafts 5 and 6 are attached to the vertical motion driver plate 19 by collars 50 and 51 , which are fixedly attached to driver plate 19 . On the top portion, hollow shafts 5 and 6 are mechanically connected to the capping head 12 .
Vertical motion driver plate 19 moves up and down by the action of a linear actuator, indicated generally at 74 , and being comprised of pneumatic cylinders 9 and 10 . Cylinders 9 and 10 are fixedly attached to horizontal carriage plate 36 . Plate 36 contains clearance holes (not shown) for accommodating the extension rods of cylinders 9 and 10 , which are shown respectively at 52 and 53 . When the piston rods of cylinder 9 and 10 are retracted the capping head 12 is in its lower position Such lower position is used for torquing the containers 11 . The upper position is used when the containers 11 are moved underneath the cap driver assembly 401 . Thus, the vertical motion driver plate 19 is imparted with vertical movement by the action of pistons 9 and 10 .
Compressed air for inflating the elastic gripper 201 is supplied from a compressor means (not shown) via an air/vacuum port 67 . The port 67 is connected to hollow shaft 6 by a channel or orifice inside plate 19 . A regulating valve and pressure gauge (not shown) are utilized by the operator to manually adjust the air pressure in the elastic gripper 201 disposed within the cap driver assembly 401 as most clearly seen in FIG. 4 . This provides control of the gripping force applied to a cap 40 during the torquing operation. At the same port 67 shown in FIG. 1, a vacuum source is also connected to permit quick deflation of the insert 201 at the end of each torquing cycle.
In general, the inflatable insert 201 wraps around the entire periphery of a cylindrical cap. However, the insert 201 is also capable of gripping caps of an irregular shape such as caps (not shown) having a pour spout because the insert 201 is sufficiently flexible to conform to an irregular shape. Advantageously, this permits a reduction of the pressure applied to such a cap and avoids damage thereto.
Still referring to FIG. 1, a servomotor 8 is mounted on horizontal carriage plate 36 . Servomotor 8 is electrically connected to a servoamplifier. Further description of how the servomotor 8 is driven by the servoamplifier is provided in conjunction with FIG. 8 . At the upper end thereof servomotor 8 includes a spline mechanism, indicated generally at 73 , that drives a rotatable drive shaft 7 . The operation of the spline mechanism 73 will be described in further detail in connection with FIG. 7 .
On the lower end thereof servomotor 8 includes an encoder 20 . Encoder 20 is electrically connected to a servocontroller (not shown). Drive shaft 7 extends into the capping head 12 within the hollow shaft 5 . This permits rotational motion of shaft 7 inside the hollow shaft 5 even while shaft 7 is moving up and down. The rotational motion of shaft 7 is transmitted to spindle shaft 4 by a gear mechanism shown and described in connection with FIG. 6 .
FIG. 4 depicts a cross-sectional view of the cap driver assembly 401 in its operative position in relation to a container 11 disposed underneath it. In this view the container 11 has been loosely capped at the cap placement station 44 . The cap driver assembly 401 encloses the elastic gripper 201 , which is disposed in functional position around the cylindrical sleeve 301 as shown in FIG. 4 . The elastic insert 201 comprises a cylindrical body 202 and two integrally formed, overhanging flanges 203 and 204 as most clearly shown in FIG. 2. A circular cavity 205 extends along the entire length of the insert 201 . In the preferred embodiment the inflatable insert 201 is a unitary construction being fabricated of any elastomeric material of suitable physical and chemical properties for this application.
The inflatable insert 201 is dimensioned such that when the insert 201 is in a deflated condition, it will provide a loose fit with a cap 40 within the cap driver assembly 401 in position over the cap 40 as shown in FIG. 4 . Prior to the torquing operation the inner surface of the elastic insert 201 surrounds the entire circular periphery of the cap 40 as illustrated.
The cap driver assembly 401 further comprises a housing 408 having a central cavity 416 . A cap stabilizing plunger 407 is disposed in cavity 416 of the cap driver assembly 401 to ensure that any misaligned caps can be straightened prior to starting the torquing operation. The cap stabilizing plunger 407 can be either rigid or resilient in construction.
The top portion of the cap driver assembly 401 has affixed to it a circular plate 413 that is threaded to receive the spindle shaft 4 . The top portion of plate 413 contains a groove for seating an O-ring 415 . When the assembly 401 is threaded onto the spindle shaft 4 , the O-ring 415 is compressed and forms an air tight connection between the capping head 12 and the cap driver assembly 401 . Of course, the cap driver assembly 401 can be easily removed by unscrewing it from the spindle shaft 4 . Thus, the insert 201 is replaceable without requiring major disassembly of the rotary capping apparatus 10 during maintenance procedures.
Referring now to FIG. 4 in conjunction with FIG. 1, the sequence of operations for a capping cycle will now be described. The starwheel 16 first advances a filled and loosely capped container 11 to the torquing station 45 . Movement of the containers 11 and the capping head 12 is synchronized such that each container 11 is positioned vertically and axially underneath the cap driver assembly 401 . Clamping block 17 clamps the container 11 underneath the cap driver assembly 401 in preparation for torquing. The capping head 12 then descends to its lowermost position, which is slightly above the upper end of the container 11 . The capping head 12 moves down a predetermined distance, which has been determined by the initial height of the cap driver assembly 401 and the height of the container 11 .
Thereafter, the elastic gripper 201 inflates into tight gripping engagement with a cap 40 disposed within the insert 201 such that torque can be applied to the cap 40 by rotation of the cap driver assembly 401 without deforming or damaging the cap 40 . It will be appreciated by those skilled in the art that the elastic insert 201 can expand only in a direction toward the longitudinal axis A of the cap driver assembly 401 due to the constraining effect of the surface of the sleeve 301 .
FIG. 3 illustrates the cylindrical sleeve 301 including a plurality of holes 303 formed around its body. In the preferred embodiment four holes of approximately ¼″ diameter, each located 90 degrees away from the prior hole are formed at the same vertical height. The holes 303 permit the passage of compressed air. The sleeve 301 is preferably made of stainless steel to avoid corrosion.
With further reference to FIG. 4, the mechanism for gripping and tightening a cap will now be described in greater detail. Compressed air is fed through bore 403 in spindle shaft 4 . The compressed air then flows into cavity 405 , into bores 404 and 406 , and air chamber 402 . The air flows through the holes 303 of sleeve 301 and inflates the elastic insert 201 . Note that the elastic insert 201 is shown in its deflated position in FIG. 4 . Upon inflation, the elastic insert 201 tightly grips the circular periphery of the cap 40 in cavity 416 of the cap driver assembly 401 . After securing the cap 40 , the cap driver assembly 401 turns to tightly screw the cap 40 onto the neck of container 11 to the predetermined torque programmed in the console 27 .
Servomotor technology and a computer program are utilized to stop the servomotor 8 at a predetermined torque setting. Parameters for setting the proper torque are entered in operator console 27 . The console is elevated by post 28 as seen in FIG. 1 for ease of use. Briefly, it will be noted that the servomotor 8 is able to detect the error in rotation that is caused by the resisting force exerted on the cap 40 . As a rule the greater the error, the greater the torque applied. The operation of this servomotor 8 will be explained hereinafter in further detail.
Once the predetermined torque is attained, vacuum is applied through port 67 on plate 19 illustrated in FIG. 1 . The vacuum is transmitted through spindle shaft orifice 403 and exerts negative pressure on the insert 201 and contracts it to its original condition. In this manner, the cap driver assembly 401 provides for a quick release of the associated cap 40 before the chuck moves back up to start a new cycle. At that point, the cap driver assembly 401 is raised and the container 11 is indexed away from the cap torquing station. At the same time, a newly capped container 11 arrives at the torquing station to start the next cycle.
FIG. 5 is an orthogonal view of the gear drive mechanism within the capping head 2 of FIG. 1 . This mechanism serves to transmit a precisely controllable torque to each cap 40 . Hollow shaft 5 is fixedly attached to the housing 508 of capping head 2 by means of suitable fasteners such as screws (not shown). The housing includes a top plate 509 and a housing body 510 . The housing body has a central cavity 512 for accommodating a gear mechanism and two parallel side cavities for accommodating the two vertical shafts namely driver carrier shaft 5 and air/vacuum channel shaft 6 (shown in FIG. 1) which move up and down together to impart vertical movement to the capping head 12 . Rotatable shaft 7 , which is disposed inside driver carrier shaft 5 carries rotational motion in a clockwise direction as viewed from the top in FIG. 1 and FIG. 6 . At its lowermost portion, rotatable shaft 7 is engaged with the motor shaft via spline mechanism 73 to be described hereinafter in further detail. External spur gear 501 is affixed to the end of rotatable shaft 7 . At its uppermost portion, rotatable shaft 7 is engaged with spur gear 501 . Rotatable shaft 7 moves up and down with driver carrier shaft 5 .
When the input torque motor turns shaft 7 and the attached external spur gear 501 in a clockwise direction, this rotational movement is transmitted to counterclockwise movement of external spur gear 507 , which in turn transmits clockwise rotation to external spur gear 503 . Spur gear 503 transmits the rotational motion to spindle shaft 4 , which in turn transmits it to the cap driver assembly 401 . The capping head 12 is provided with antifriction bearings such as ball bearings 504 , 505 and 506 , which respectively support shafts 4 , 7 , and 507 .
FIG. 6 is a top view of the capping head 12 with the top plate 509 removed showing the arrangement of the gear mechanism and shafts. Air/vacuum carrier shaft 6 is parallel to driver carrier shaft 5 and moves the cap driver assembly 401 up and down in conjunction with driver carrier shaft 5 . Shaft 6 provides pressurized air and vacuum for the elastic gripper 201 . The clockwise rotation of the spur gear 501 when shaft 7 turns is shown by the directional arrow 604 . Spur gear 502 rotates in a counterclockwise direction as shown by directional arrow 603 . Spur gear 503 rotates in a clockwise direction as shown by directional arrow 602 . A channel 601 extends from shaft 6 to carry the air/vacuum from shaft 6 to channel 403 (refer to FIG. 4 ). The channel 601 is formed in the top plate 509 and cannot actually be seen when the top cover 509 is removed, but its location is shown in FIG. 6 for purposes of clarification.
FIGS. 7 A through 7 B′ are a series of cross-sectional views taken through the capping head 12 and the cap driver assembly 401 depicting the arrangement of the internal components thereof and their operation including the gear mechanism, shaft rotation and, compressed air/vacuum flow during actuation of the elastic gripper 201 .
FIG. 7A is a sectional view taken along the line A—A of FIG. 6 showing capping head 12 and the cap driver assembly 401 and the components thereof, This illustration permits a full view of the rotatable drive shaft 7 . The direction of rotation of rotatable drive shaft 7 and cap driver assembly 401 is shown by directional arrows 723 and 724 respectively.
FIG. 7B is a sectional view of the capping head 12 and the cap driver assembly along the line B—B of FIG. 6 . The interior channel 720 of the hollow shaft 5 is illustrated. The channel 720 inside shaft 5 permits the compressed air to exhaust from the gripper 201 via air chamber 402 , orifice 406 , and cavity 405 either by opening a valve to exhaust the air or by applying vacuum to exhaust it more rapidly. Directional arrow 721 shows the direction of flow of the exhausted air or the applied vacuum. The gripper 201 is shown in a deflated condition in this view.
FIG. 7 B′ is a sectional view along the line B′—B′ of FIG. 6 . It is similar to FIG. 7B except that it illustrates the gripper 201 in an inflated condition. Compressed air enters the cavity 725 between the insert 201 and sleeve 301 , which expands under the air pressure and actuates the gripper 201 to permit the gripping and torquing of caps 40 . The path of the compressed air for actuation of the gripper 201 is indicated by directional arrow 722 which shows air flowing into channel 720 of the rotatable drive shaft 5 into channel 601 , orifice 403 , orifice 406 , air chamber 402 , holes 303 and into cavity 725 within the insert 201 .
Referring to FIG. 9 there is shown therein a spline mechanism, indicated generally at 73 , which mechanically couples the servomotor 8 to the drive shaft 7 . The spline mechanism 73 transfers rotations from the servomotor 8 to the rotatable shaft 7 in such a way that allows drive shaft 7 to move up and down simultaneously with rotation. As described hereinabove, downward movement of the capping head 12 is required for positioning the cap driver assembly 401 for gripping of caps to be torqued. After the torquing cycle is completed, the gripper 201 is released and the cap driver assembly 401 moves upwardly to allow the capped container to be removed and a new container to be brought into the torquing station. This up/down movement with simultaneous rotation of the drive shaft 7 is facilitated by the construction of the spline mechanism, indicated generally at 73 , as seen in FIG. 9 . Disk 701 is fixedly attached to the output shaft 704 of the servomotor 8 . Disk 701 includes a plurality of finger shafts 703 permanently attached thereto. Disk 702 includes mating holes (shown in broken lines in FIG. 9) sized to a slip fit condition with each of the finger shafts 703 such that disk 702 is able to slide up and down in engagment with finger shafts 703 . Disk 702 is fixedly attached to rotatable shaft 7 , which carries the rotational motion when rotatable shaft 7 is moving up and down or when shaft 7 is stationary.
Referring to FIGS. 8A-8C there is shown an orthogonal view of the drive mechanism of the rotary capping apparatus 10 with the starwheel 16 removed for clarification purposes. FIG. 8A shows the capping head 12 in the raised position. When the capping head 12 is in such raised position, a container 11 can be delivered to a position underneath it for torquing by the cap driver assembly 401 . Block 76 includes linear bearings (not shown) to guide the upward and downward movement of shafts 5 and 6 carrying the capping head 12 from a raised to a lowered position Cylinder rods 52 and 53 projecting from cylinders 98 and 99 are shown in an extended position in FIG. 8 A. The servomotor 8 is provided with leads 822 , which are electrically connected to the servoamplifier (not shown). The encoder 20 is also provided with leads 821 , which are electrically connected to the servocontroller (not shown).
FIG. 8B is similar to FIG. 8A except that the capping head 12 is shown in its lowermost position. It will be noted that the cap 40 being applied to container 11 cannot be seen as it is inside cap driver assembly 401 . When the capping head 12 moves to this lowermost position, the cylinder rods 52 and 53 are retracted within cylinders 9 and 10 and cannot be seen. At the position shown in FIG. 8B, the capping head 12 is ready to drive the cap 40 onto the neck of the container 11 and torque it to the preset value.
FIG. 8C illustrates the drive mechanism again in the raised position of FIG. 8A with the container 11 and cap 40 removed for purposes of clarity to show the vertical movement of the capping head 2 is supported by the drive carrier shaft 5 and the air/vacuum channel shaft 6 , which move up and down together.
FIG. 10 is a schematic representation, which illustrates the operation of the rotary capping apparatus of the present invention. The operation of the present apparatus is controlled by a so-called closed loop control system. A closed loop system being one in which an actual measured variable (i.e. angular position) is sent back as feedback to the servocontroller 803 for comparison with the desired variable (i.e. angular position error) to provide control based on the error found in the comparison (i.e. desired position vs. actual position). The error between desired and actual position represents the torque applied to the cap when applying it to a container. When the desired torque has been applied, the control system stops applying torque, the container 11 is removed from the cap driver assembly 401 , and a new container is moved into position.
Still referring to FIG. 10, the present control system includes an operator console 27 , a central processing unit (CPU) 801 , a servocontroller 803 , a servoamplifier 804 , a servomotor 8 and an encoder 20 . The console 27 is connected to the CPU 801 for entry of parameters that control the movement and gripping action of the cap driver assembly 401 . The servocontroller 803 is interfaced with CPU 801 for bi-directional communication.
The servocontroller 803 generates a theoretical position profile, which is a function of time, t: Pos-theor (t). The servocontroller 803 receives position feedback from an incremental position monitoring device such as encoder 20 . The servocontroller 803 generates an output control signal S(t) which is sent to the servoamplifier 804 . The output control signal is a function of time, t. The servocontroller 803 executes proportional, integral and derivative (PID) control as follows: The position feedback from the encoder 20 is sent to operating block 806 which generates the real position, POS_REAL(t) of the rotary capping apparatus as a function of time, t. The POS_REAL(t) is fed into a comparator junction 802 .
In one embodiment of this invention, an incremental quadrature encoder is used with two channels: A and B, generating 500 pulses per revolution Channels A and B are shifted by +90 or −90 electrical degrees in relation to each other, depending on the direction of rotation. The servocontroller 803 can read incoming pulses from the encoder 20 and calculate precisely the current position of the drive shaft: POS_REAL(t). At the same time, junction 802 receives the theoretical position POS_THEOR(t) from operating block 805 . At the beginning of each cap torquing cycle, POSITION PROFILE GENERATOR block 805 generates the POS_THEOR(t) from parameters received from the CPU 801 . These parameters include the angular acceleration of the rotation of the capping apparatus, the angular velocity of the rotation of the present capping apparatus and an allowable position error, E LIMIT. These parameters can be changed via the console 27 .
At junction 802 the theoretical position generated, POS_THEOR(t) is compared to the real position POS_REAL(t) and a Position Error, E(t) is generated. The mathematical relation is E(t)=POS_THEOR(t)−POS_REAL(t). This comparison is carried out by adding the theoretical position as a positive number and adding the real position as a negative number as indicated by the positive and negative symbols adjacent to junction block 802 . The PID FILTER block 807 then generates the control signal S(t) as a function of the position error E(t). S(t) is the PID output and is obtained from the following well known mathematical expression for PID control: S(t)=Kp*E(t)+Ki ∫E(t) dt+KdE(t)/dt. Kp*E(t) is the proportional control term, Ki∫E(t) dt is the integral control term and +KdE(t)/dt Ki is the derivative control term S(t) is the signal output. Kp, Ki and Kd are constant coefficients, which are experimentally determined and adjusted to produce an optimal control signal S(t), The adjustment of Ki and Kd results in greater stability of the motor.
For purposes of illustration, one embodiment setting Ki=0 and Kd=0 will provide an adequate control signal S(t). Thus, S(t)=Kp*E(t). The servocontroller 803 is programmed to set S(t) to zero when the position error E(t) exceeds a certain predetermined value E_LIMIT. The E_LIMIT value is adjustable from the console 27 and is stored in the CPU memory. If the error E(t) is less than the predetermined value E_LIMIT, the control signal is set to S(t)+Kp*E(t).
On the other hand if E(t) is greater than E_LIMIT, then S(t) is set to zero. At this point the FLAG is set to 1. Setting the FLAG to 1 causes the cycle to start anew. Thus, the maximum value of the signal S(t) before it becomes zero is Max(S)=Kp*E_LIMIT. The signal S(t) is sent from the servocontroller 803 to the servoamplifier 804 where it is converted to a value of electrical current I(t) by the following mathematical relationship: I(t)=GAIN*S(t), where GAIN is a constant coefficient. The maximum current I(t) is related to the maximum signal S(t) as follows: Max (I)=Gain*Max (s); or Max (I)=Gain KpE_LIMIT. The servoamplifier 804 controls the servomotor 8 with the current I(t). The servomotor 8 in turn converts the electrical current I(t) into the torque TQ(t) that is applied to the motor shaft. TQ(t)=Ka*I(t), where Ka is a constant coefficient. The maximum torque is related to the maximum current as follows: Max TQ=Ka*Max (I); or Max TQ=Ka*GAIn*Kp*E_LIMIt. Considering that Ka, Gain, Kp are constants, Ka*Gain*Kp is also a constant. Thus, Max TQ=CONSTANT E_limit. In summary, the servocontroller 803 reads the maximum torque after capping is completed and the cap driver assembly 401 cannot rotate any further due to the solid stop.
The position error (difference between Pos_THEOR(t) and POS_REAL(t) increases quickly since the theoretical motion profile, POS_THEOR(t) is calculated based on the continuous velocity, so POS THEOR(t) continues to increase. However, POS_REAL(t) is restricted and remains almost unchanged. As soon as the position error E(t) exceeds the preset limit E_LIMIT, which results in reaching the torque associated with it according to MaxTQ=CONSTANT*E_LIMIT, the signal S(t) will be reset to zero by the servocontroller 803 and consequently I(t)=0 as well as TQ(t)=0. When the servoamplifier 804 receives the incoming signal of S(t)=0, it will remove any voltage applied to the servomotor 8 resulting in no current being sent to the servomotor, i.e. I(t)=0. The servomotor 8 will release the torquing force from its shaft, and the servocontroller 803 will set a flag in block 808 noting this event for the CPU 801 . As can be seen from MAXTQ=CONSTANT*E_LIMIT, the maximum applied torque is adjustable by setting the value of E_LIMIT. This value is entered and adjusted from the console 27 .
Still referring to FIG. 10, the torque produced by the servomotor 8 is transmitted to the cap driver assembly 401 by way of spline mechanism 73 , rotatable shaft 7 , and the gear mechanism 511 as described in connection with FIGS. 1 and 9. At the same time that the hereinabove described servomechanism is controlling the torque of the cap driver assembly 401 , the CPU 801 is operating the gripper 201 by inflating it prior to torquing and deflating it after torquing. Prior to any torquing action, the cap driver assembly 401 is moved to its lowest vertical position by the action of the vertical motion driver plate 19 , which moves the cap driver assembly 401 up and down as previously described in conjunction with FIG. 1 . An air pressure source 810 provides air to pneumatic switch 809 , which sends air through the air/vacuum channel shaft 6 to the gripper 201 in the cap driver assembly 401 . At the end of each cycle, the pneumatic switch 809 is activated and air pressure is cut off. Instead of air pressure, a vacuum source 811 provides vacuum through the pneumatic switch 809 and air/vacuum channel shaft 6 into the gripper 201 . This permits rapid deflation of the gripper 201 . After deflation, the cap driver assembly 401 is raised by the action of vertical motion driver plate 19 , which is activated by linear actuator 74 . Linear actuator 74 is activated by an electrovalve (not shown).
FIG. 11 consists of four related diagrams. The first diagram, FIG. 11A shows the theoretical position of the cap driver assembly 401 , POS_THEORET(t) that is generated by the servomotor 8 as a function of time, t. FIG. 11B shows the actual position of the cap driver assembly 401 as a function of time. FIG. 11C shows the position error, which is the difference between the theoretical position POS_THEOR(t) and the actual position POS_REAL(t). At the beginning of the cycle, the position error is small. As a cap 40 is driven onto a container 11 , there is a point at which the position error begins to increase. This is the point at which the cap 40 has been completely screwed onto a container 11 and starts being torqued. At a further point in time, the position error reaches the value of E-Limit, at which point the cycle is stopped. FIG. 11D plots the torque as a function of time. The torque limit TORQUE_LIMIT is reached when E-LIMIT is reached.
FIG. 12 depicts a timing sequence illustrating when specific actions in the present capping process occur. The horizontal lines in FIG. 12 represent time proceeding from left to right. In FIG. 12 if a portion of a horizontal line is raised it indicates that the subject device is active. The production cycle begins at t=0 time. Prior to the cap driving cycle, a new container 11 is moved in place by the star wheel 16 . This happens between t=0 and t=1. During this time, the cap driver assembly 401 is in the up position, vacuum to the inflatable gripper 201 is applied, the cap driver assembly 401 is not being rotated, the torque limit has not been reached and the container clamping mechanism is released.
At time t=1 a container 11 has been moved into position, the cap driver assembly 401 is commanded by the CPU to move down, and the container 11 is held in place by the clamping mechanism. At time t=2 air pressure is applied to the gripper 201 so that a cap 40 is held in position. Thereafter, at t=3, the servomotor 8 is commanded to apply torque and to rotate the cap driver assembly 401 to screw the cap onto the container. This is continued until t=4, at which time the torque limit is reached. The cap 40 initially introduces a small resistance to the servomotor 8 . Thus, the torque and associated position error E(t) of the servomotor shaft is relatively small until the cap is screwed on almost all the way at which time the resistance starts to increase. As soon as the value of E(t) exceeds the limit (i.e. E-LIMIT) as discussed hereinabove, the current (i.e. I(t)) is removed from the servomotor 8 via setting S(t)=0, where E(t) is a position error calculated as a difference between theoretical position and a real position of the motor shaft. S(t) is the outcome of the PID filter filtering E(t), I(t) is proportional to the S(t) signal and motor torque TQ(t) is proportional to I(t). S(t) is proportional to E(t), thus TQ(t) is proportional to E(t). Since Max E(t)=E_LIMIT, Max TQ(t) is proportional to E_LIMIT. The event of E(t) exceeding E LIMIT is marked as t=4 and the motor 8 will stop a moment later as a result of mechanical inertia of the load attached to its shaft and the fact that the current I(t) was set to zero via S(t)=0. Immediately after that, at time t=6, the gripper 201 is commanded to release by application of vacuum. After the cap is released, at time t=7, the cap driver assembly 401 is commanded to move up to clear the container movement. At time t=8, the cap driver assembly 401 is in its up position and the container clamping mechanism is commanded to release the container. A moment later, at time t=9, the machine is ready to repeat the cycle.
Thus, again at time t=1, a cap is placed on the container at the prior position in preparation for torquing in the next cycle. At this juncture optional functions like filling the container with a liquid or powder may take place. These functions last until time t=x. The time t=8 will occur after t=7 or t=x, whichever is larger.
FIG. 13 is a schematic representation depicting the operation of the feeder bowl automatic height adjustment function of the present rotary capping apparatus. This feeder bowl automatic height adjustment of the present invention is also controlled by a closed loop control system.
Referring to FIGS. 13 and 14 collectively, the present height adjustment system includes the operator console 27 , the central processing unit (CPU) 801 , the servocontroller 803 as described hereinabove and, in addition, an ultrasonic transmitter 76 , the horizontal carriage plate 36 , the height adjustment motor 68 , an amplifier 910 and operating blocks 911 and 912 .
In the height adjustment system the console 27 is connected to the CPU 801 for entry of parameters that control the height of the capping head 2 . A signal from the ultrasonic transmitter representing the distance 85 shown in FIG. 14 to the horizontal carriage plate 36 is sent to the CPU 801 for positional feedback of the horizontal carriage plate 36 . When the height adjustment motor 68 rotates, the horizontal carriage plate 36 moves up or down, and the capping head 12 moves with it. The distance between the carriage plate 36 and the bottom plate as at 85 corresponds to the height of container 11 . The container height parameter is entered from the console 27 and stored for a particular product. When a new product is selected with a new value of height or when the height is manually changed from the console 27 , the CPU 801 compares the height value with the measured distance as at 85 from the ultrasonic transmitter in operating block 911 shown in FIG. 13 . If the distance 85 is greater than the height of the container 11 , then the CPU 801 sends a signal to the amplifier 910 which is in turn sent to the height adjustment motor 68 rotating the lead screw 70 in a clockwise direction moving the horizontal carriage plate 36 and thus the capping head 12 downward. On the other hand, if the distance 85 is less than the height parameter in the console 27 , then lead screw 70 is rotated in a counterclockwise direction moving the horizontal carriage plate 36 upward. Thus, depending on the difference in these two values, the CPU 801 sends a signal to drive the horizontal carriage plate 36 up or down until said difference is small with an allowable tolerance. Thus, the present apparatus will automatically adjust the height of the feeder bowl 22 to the correct level for the container being processed.
FIG. 14 is an orthogonal view of the present rotary capping apparatus 10 depicting the vibratory bowl 22 and the vibratory bowl support frame, indicated generally at 934 , with the sheet metal cover 97 as seen in FIG. 1 removed to permit viewing of the internal components of the vibratory table adjustment mechanism. The vibratory bowl 22 is mounted on the free standing frame 934 such that vibrations are not transmitted to the rotary capping apparatus 10 .
Frame 934 includes four vertical members of which only two, namely 931 and 932 are shown in FIG. 14 . The lowermost portion of each vertical member is disposed within a thrust bearing. Only thrust bearings 928 and 929 associated with members 931 and 932 can be seen in this view. Such thrust bearings carry the weight of the frame 934 and bowl 22 . Frame 934 is also provided with a top horizontal plate 930 and a bottom horizontal plate 933 . The frame 934 can be moved up or down via rotations of motor 921 . A leadscrew is attached to each of the vertical frame members; however, only leadscrews 855 and 856 associated with members 931 and 932 can be seen in FIG. 14 .
A drive pulley 925 is attached to the shaft of motor 921 to drive the upward/downward movement of the frame 934 via belt 926 . Although each leg of the vibratory frame is provided with such a pulley, only pulleys 923 and 924 can be seen in this view. It will be understood that belt 926 surrounds and engages all four pulleys. Rotation of the pulleys in one direction causes the frame 934 to move upwardly and rotation in the opposite direction causes the frame 934 to move downwardly.
A sensor 87 is mounted on the rotary capping apparatus 10 to detect the lower edge 920 of the vibratory bowl 22 . More particularly, sensor 87 is mounted on bracket 86 , which is in turn mounted on track support plate 80 . The track support 80 also carries the feeder track 97 . The track support 80 is supported by a set of shafts 81 that are attached to carriage plate 36 . A feeder track 97 for the disbursement of caps 40 is fixedly attached to the vibratory bowl 22 . Container caps 40 exit the vibratory bowl 22 through feeder track 97 and are delivered into the transfer track 23 .
Still referring to FIG. 14, the height adjustment is calculated based on an offset such that the feeder track 87 and the transfer track 23 are at the same level and the container caps 40 can move freely. During installation of the machine, this is accomplished by moving the sensor 87 on bracket 86 such that it detects the edge 920 of the vibratory bowl when the feeder track 97 and transfer track 23 are on the same level. Thereafter, the height adjustment of the tracks 97 and 23 is automatic.
When an operator enters a new container height in the CPU 801 via the console, the height of transfer track 23 is determined by the procedure described hereinabove in connection with FIG. 13 . As the sensor 87 is moved on transfer track 23 to accommodate the new height setting, the sensor moves away from edge 920 of the vibratory bowl 22 . The CPU 801 then commands motor 921 to rotate and move the vibratory bowl frame 934 up or down to align the edge of the bowl 22 with the sensor 87 , which event is detected by the sensor and a signal is sent to the CPU 801 . A rotating wheel (not illustrated) or other alternative transfer means is functionally disposed above the caps 40 within transfer track 23 so as to advance the caps 40 into position at the cap placement station 44 .
FIG. 15 is a schematic diagram depicting the operational steps followed by the present capping apparatus in order to move the vibratory bowl frame 934 to a new height setting. As described hereinabove, an operator first enters a desired new height in the console. This is represented by step 974 in FIG. 15 . In the next step 975 , the new height is sent to the CPU. The CPU then sends the new height parameter to operating block 976 which determines whether the sensor 87 is on. If the sensor 87 is on, then a signal is sent to the motor 921 for raising the vibratory frame as at block 977 in FIG. 15 . If the sensor 87 is not on, then a signal is sent to the motor 921 to lower the vibratory bowl frame 934 . After the motor 921 is operated to lower the frame 934 , the sensor is checked again as at block 979 . If the sensor 87 is still not on, this process continues and the operator continues to lower the vibratory frame. Once the sensor 87 is on, the motor is stopped as at block 980 . When the present apparatus recognizes that the sensor 87 is on the edge 920 of bowl 22 as at box 981 , a completion signal is transmitted to the CPU.
It will be apparent from the foregoing description that this invention provides for a variety of improved features with respect to rotary capping apparatus and to closure grasping and torquing apparatus. The level of torque employed in securing caps on containers is digitally and precisely adjustable and can be conveniently reset by entering the appropriate parameters on a computer console.
Although not specifically illustrated in the drawings, it should be understood that additional equipment and structural components will be provided as necessary, and that all of the components described hereinabove are arranged and supported in an appropriate fashion to form a complete and operative system incorporating features of the present invention.
Moreover, although illustrative embodiments of the invention have been described, a latitude of modification, change, and substitution is intended in the foregoing disclosure, and in certain instances some features of the invention will be employed without a corresponding use of other features. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of invention. | A rotary capping apparatus and feedback control apparatus for regulating torque applied to screw-on type caps for containers is disclosed. The present system is integrated into a machine suitable for a clean-room environment. The apparatus includes a supporting frame whereon a computer-controlled driving mechanism including a servomotor for transmitting a predetermined torque to an inflatable gripping device actuated by compressed air for gripping and torquing such caps is provided. The inflatable gripper is imparted with automatic vertical height adjustment to accommodate containers of various sizes. The present rotary capping apparatus provides an integrated closed loop feedback control system utilizing a computer for setting parameters for regulating the application of such torque and a servocontroller interfaced for bidirectional communication with the computer. The servocontroller generates an output signal to the servomotor based upon the position of the rotary capping apparatus for precise torquing of the caps onto containers. The rotary capping apparatus also incorporates automated cap and container delivery mechanisms, which provide for synchronous advancement of the caps and containers to different stations within the machine for continuous processing. | 1 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The subject invention relates to a transport device having a portable work surface, and particularly to a device capable of carrying a portable computer, or the like, and associated devices and providing a work surface for supporting the devices during use.
2. Description of the Related Art
The use of computers has increased steadily over the last decade. In fact, the ability to access, store, and manipulate data with computers has made computers an indispensable business tool. Further, recent technological advances with respect to miniaturization has allowed substantial computing power to be accommodated in a small portable package. Such devices are known as "laptop" or "notebook" computers The development of such portable computers along with the flexibility of remote systems has resulted in an increase in the number of people traveling with computers and working in "virtual spaces" which can be anywhere that the person and computer happen to be, such as an airport, the office of another, and hotel rooms.
Although computers have become smaller, and lighter, the peripherals required to support mobile computing in virtual spaces is quite large and thus the traveling weight of a complete system can be quite high. For example, a complete system may include a modem, cellular phone, printer, instruction manuals, power converters, and cables. Therefore the load handling requirements of the typical mobile worker can be substantial
Additionally, increased use of keyboards and other devices associated with the operation of a computer have recently been discovered to be the source of repetitive strain injuries. Studies have shown that repetitive strain injuries, as well as back strain, eye strain, and other work related injuries can be alleviated by proper posture and support. In fact, recent ADA and OSHA regulations have begun to define standards for computing support. To comply with these regulations, and to reduce medical expenditures, many employers have begun to invest in adjustable keyboard supports, wrist rests, foot rests and other devices to properly position and support workers who operate computers. However, these devices are fixed devices which cannot easily be moved form one location to another along with the worker.
In addition, portable luggage carts are well known. Such devices have wheels and can be collapsed for storage. However, known luggage carts do not have any type of work surface on which a computer, or the like, can be supported during use. Clearly, luggage carts do not address the above-noted support problems associated with mobile computing.
SUMMARY OF THE INVENTION
In view of the above, it is an object of the invention to provide a device which facilitates transport of a portable computer, or other work device, and associated devices.
It is a further object of the invention to provide a transport device which easily converts to a work surface for supporting a portable computer, or the like.
It is still a further object of the invention to provide a device which properly supports a worker who is operating a computer, or the like.
In order to accomplish the objectives above, the invention includes a main stem, a support base, and a keyboard tray. Both the support base and the keyboard tray are adjustable on the main stem to allow the device to achieve various configurations. In a collapsed state, wheels coupled to the base are accessible to allow the device to be easily moved. The position of the keyboard tray is easily adjustable and a wrist support can be coupled thereto. The invention also allows for the configuration of a foot support creating a stable base in the engaged state. Luggage can be coupled to the device by conventional straps or by being locked into the extended "members" of the collapsible foot rest/base.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be better understood based on the following description of preferred embodiments thereof taken in connection with the Figures in which:
FIG. 1 illustrates a first preferred embodiment in the transport mode with a piece of luggage supported thereon;
FIG. 2 is a side view of the first preferred embodiment in a work mode supporting a portable computer and a utility bag with side "members" collapsed to form the footrest/base;
FIG. 3A illustrates the first preferred embodiment in the transport mode without any luggage after the palm rest has been removed;
FIG. 3B illustrates the optional utility bag of the first preferred embodiment;
FIG. 3C illustrates the optional luggage of the first preferred embodiment;
FIG. 4 is a perspective view of the first preferred embodiment in the work mode;
FIGS. 5A-C illustrate typical operator posture while using the preferred embodiments;
FIG. 6 is a front perspective view of a second preferred embodiment;
FIG. 7 is a rear perspective view of the second preferred embodiment;
FIG. 8 is a perspective view showing the stem channel configuration in detail;
FIG. 9 is a top view showing the stem channel configuration in detail;
FIG. 10 is a side view showing the stem channel configuration in detail;
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIGS. 1 and 3A illustrate the first preferred embodiment in a transport mode. Transport 20 is constructed essentially of three main parts. Stem 22 and two moveable members 24. Once moveable member 24 is disposed on each side of stem 22, it defines a substantially flat surface when moveable members 24 are in the extended position as shown in FIG. 3. Movable members 24 are each constructed of upper portion 24a, middle portion 24b and lower portion 24c which are hinge connected together by hinges h1 and h2. Hinges h1 and h2 can be a hinge pin extending through holes formed in the respective portions or any other appropriate hinge device. Upper portions 24a are slidably mounted to stem 22 to be slidable up and down in the direction indicated by arrow A in FIG. 1. For example, upper portions 24a can have a protrusion thereon which is received in a track groove defined in a side of stem 22. Lower portions 24c are pivotally connected to stem 22 at point p by a pin or the like. Tray 30 is secured to stem 22, in a manner which is discussed in greater detail below, to extend transversely from stem 22. An elongated bar serves to connect upper portions 24a to each other. The elongated bar extends behind stem 20.
When transport 20 is in the transport mode, luggage 60 and utility bag 50 can be attached thereto by velcro straps 52, bungee cords or any other appropriate means. Transport 20 can then be pulled on wheels 28 in a manner similar to a conventional luggage cart as illustrated in FIGS. 5A and 5B. Telescoping handle 36 is provided to allow transport 20 to be easily pulled. Typically, utility bag 50 is used for carrying the computer and peripherals associated with a portable computer. However, any combination of containers can be mounted on transport 20 and these containers can, of course contain a computer or any other items needed by the user such as clothes and toiletries.
In the preferred embodiment, moveable members 24 each have elongated channel 32 formed therein. Channel nuts 34 are affixed to a back surface of luggage 60 and can be slid into respective channels 32 to fix luggage 60 to transport 20. Specifically, luggage 60 can be lifted above transport 20 so that channel nuts 34 oppose the upper opening of respective channels 32 and luggage 60 can be lowered so that channel nuts 34 slide into channels 32. A front portion of channels 32 is narrowed so that channel nuts 34 can only exit channels 32 through the top opening thereof. Channel nuts 32 can be formed integrally on luggage 60 or conventional luggage can be retrofitted to include channel nuts 34.
Once luggage 60 is lowered onto transport 20, lock bar 40 can be attached to stem 22 by thumbscrew 73 which includes a bolt extending through slot s formed in an upper portion of stem 20 and members 24. Alternatively, lock bar 40 can have thumb screws, or the like coupled thereto which can be threadably engaged with an upper portion of stem 20. Lock apparatus 44 can be tightened from a rear portion of transport 20 while engaged with a threaded nut, or the like, formed on lock bar 40 to fix lock bar 40 to stem 22 and prevent luggage 60 from moving upward out of channels 32 and detaching from transport 20.
When the user has reached a destination at which a work surface is needed, i.e. a virtual workspace is to be created, luggage 60 can be removed in a manner opposite the attachment procedure described above. At this time, transport 20 can be easily converted to a work mode. Specifically, tray 30, which is secured in channel 70 formed along a length of stem 20 is moved upward, and relocated at the top of stem 20. FIGS. 8-10 illustrate the connection between platform 30 and stem 20 in detail. Angular plate 72 is fixed to an edge of platform 30. Angular plate 72 is shaped to conform to a cross section of channel 70 so that when angular plate 72 is received in channel 70, it can slide along channel 70 but is restrained from lateral or torsional movement. Second locking device 45, similar to locking device 44 described above, serves to secure tray 30 to stem 20 while angular plate 72 is received in channel 70. Second locking device 45 can be released to allow tray 30 to slide. At this time, first locking device 44 can be used to lock tray 30 in place at an upper portion of stem 20. In this position, tray 30 serves as a work surface. First locking device and tray 30 can be moved along slots to allow tray 30 to be locked at a desired height which is ergonomically correct for the user.
To provide a base, hinge portions h2 can be moved in the direction of arrow B in FIG. 1. This movement causes upper portion 24a to move downward and lower portion 24c to pivot about pin p (clockwise in FIGS. 1 and 2). Hinge portion h2 is restrained from further movement in the direction opposite to arrow B through engagement with stem 20 or construction of the hinge itself, for example. Also, first lock apparatus 44 can extend laterally (see FIG. 7) to prevent movement of central portion 24b to the left in FIG. 1 and thus prevent the central hinge portion h2 from moving further in a reverse direction. Further, the lock apparatus can be engaged with upper portion 24a to prevent linear movement thereof and thus prevent reverse movement of central hinge portion h2.
In the working mode illustrated in FIG. 2, central portion 24b serves as an angled footrest and lower portion 24c serves as a stable base to support stem 22 and tray 30. Lacking apparatus 45 is threadably engaged with a nut, or the like, formed in the bar which connects upper portions 24a to secure moveable members in the position illustrated in FIG. 2. In this manner, a stable work surface, which can be used to support a portable computer or the like, is defined by tray 30. Also, angled foot rests are defined by central portions 24b. Finally, lock bar 40 can have a soft resilient wrist rest defined thereon and can be easily attached to an edge of tray 30 by thumbscrews coupled thereto, or the like, as illustrated in FIG. 2. This configuration, which is illustrated best in FIG. 4, provides a convenient work surface with proper ergonomic support at any location. Of course, the height of the work surface can be adjusted by loosening locking apparatus 44 and sliding tray 30 up and down along slot s and subsequently once again tightening locking apparatus 44. Also, angle adjustment for the footrests could be provided by known mechanical elements. A typical operator work position is illustrated in FIG. 5B.
FIGS. 6 and 7 illustrate a second preferred embodiment of the invention which is best adapted to use where transport of large luggage is not required. In this embodiment like elements are labeled with the same reference numerals as in the first embodiment and are not described in detail to avoid redundancy. In this embodiment, tray 30 is connected to an upper portion of stem 22 and, in the transport position illustrated in FIGS. 6 and 7, essentially parallel with stem 22. Locking apparatus 44, which is similar to locking apparatus 44 of the first embodiment, has a bolt which is threadably engaged with a nut or the like formed on a rear surface of tray 30 in order to secure tray 30 in this position. Locking apparatus 44 has a transverse bar which extends to upper portions 24a of the moveable members to also lock the moveable members in the transport position. Utility bag 50 can be secured to the transport 20 in the same manner as in the first embodiment. Further, a portable computer or other light baggage can be secured to the front or rear of the transport by strap 52.
When transport 20 is to be set into the work mode, locking apparatus 44 is first released and tray 30 is fastened to stem 22 in a manner similar to the first embodiment (see FIGS. 8 and 5c) and moveable members 24 are folded downwards in a manner similar to the first embodiment. In this embodiment, locking apparatus 44 is coupled to upper portions 24a by the transverse bar so that as the moveable members are folded downward to the work position, locking apparatus 44 moves downward along slots. When moveable members reach the proper position, locking apparatus 44 can be locked once again to secure the base and footrest of transport 20 in the work mode. Therefore, only one locking apparatus is required. Tray 30 can be secured on the extended position by the use of known locking hinges, an extendable support bar or other known devices.
From the description above, it is clear that the invention allows a portable computer and other equipment to be easily transported to any desired location and further allows a virtual work space to be set up in the desired location. In the workspace, the invention provides proper support for the computer and the operator to minimize fatigue and injuries.
The invention has been described through preferred embodiments. However, it is apparent that various modifications can be made without departing from the scope of the invention as defined by the appended claims. For example, various features of the preferred embodiments can be combined and interchanged as desired. Also, various mechanical devices can be used to secure the various portions of the invention in the desired positions. | A combination transport device and work surface has a collapsible support member and base member. In the collapsed position, the support member and base member are close to a stem of the device to define a transport surface. The transport surface can be easily moved via a handle and wheels. In the extended position, the support member and the base member extend transversely from the stem to define a work surface and a support base respectively. | 0 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to apparatus used in the processing of semiconductor wafers. More particularly, it relates to apparatus for transporting cassettes holding multiple semiconductor wafers that can be used in the automated processing of semiconductor wafers through a sequence of operations in which the wafer cassettes must be transported from one processing station to another.
2. Description of the Prior Art
The handling and storage of thin, delicate wafers for the semiconductor industry present difficult problems because of the high value of such wafers and their fragility. The wafers may be of very brittle material, such as silcon, and are usually three to six inches in diameter but only a few thousandths of an inch thick.
The processing of such wafers usually requires them to be successively bathed in and drained free of liquids, sometimes at elevated temperatures. They may also be dried, placed in an epitaxial reactor or diffusion furnace or merely transported from one location to another. In the past few years it has become common to use cassettes in the form of small baskets or racks of a size suitable to accommodate an array of wafers of a particular size to carry or store the batch of wafers during processing or transport. During processing, the cassettes together with their wafers are usually successively immersed in baths of liquids or used at other wafer batch processing stations performing other operations previously mentioned.
Several factors make it desirable to provide automation in the processing of cassettes of semiconductor wafers. First, the wafers must be processed in extremely, dust-free environments in order to achieve high yields. The hair, skin and clothing of human beings necessarily release particulate matter that can cause problems at the microscopic level in semiconductors. Second, the processing of semiconductor wafers sometimes involves hazardous or unpleasant chemicals or other environments to which human beings should not be exposed for prolonged periods. Third, the timing of certain processing operations is critical. Automated equipment is superior to human labor for repetitive sequences of time-critical operations. However, even automated equipment must be carefully designed to represent an improvement over human labor. For example, parts that move against each other can be a source of dust or particulate matter. It is also desirable to avoid direct automated or manual contact with the cassettes themselves, as this can lead to chipping, breaking or contamination of the semiconductor wafers in the cassettes.
While the semiconductor industry has developed certain standards relating to the dimensions, wafer capacity and other characteristics of the cassettes used to hold semiconductor wafers, present cassette designs (e.g., U.S. Pat. Nos. 3,923,156 and 3,961,877) do not lend themselves easily to interfacing with robotics equipment. Robotic handling equipment working with the delicacy and dexterity of the human hand is now possible in some circumstances, but such equipment is extremely expensive. Accordingly, what has been needed in the prior art is apparatus that aids in the use of automated equipment for handling cassettes that hold semiconductor wafers (or other similar semiconductor materials) during their processing. Such equipment will have the widest usefulness when it can interface with relatively inexpensive robotic devices and when it can serve as the interface for all manual or automated handling of cassettes, so that direct manual or automated handling of cassettes (which can lead to chipping, breaking or contamination of wafers) is avoided.
SUMMARY OF THE INVENTION
The present invention is an apparatus for holding and transporting semiconductor material cassettes during processing of the semiconductor material. In the apparatus there is a tray having at least one cassette station thereon. This cassette station comprises a cassette supporting surface, a first pair of substantially parallel cassette guides on the supporting surface and a second pair of substantially parallel cassette guides on the supporting surface located between and substantially at right angles to the first pair. The first and second pairs of parallel cassette guides form a generally rectangular boundary. A handle neck extends upwardly from the same side of the tray as the cassette guides. A handle crosspiece is connected to the handle neck and has a bearing surface oriented substantially parallel to the plane of the tray.
It is an objective of the invention to provide a carriage for conveniently holding one or more semiconductor material cassettes during processing.
It is another objective of the invention to provide a carriage for holding semiconductor material cassettes that is easily grasped or engaged by automated equipment.
It is a further objective of the invention to provide a carriage for transporting semiconductor material cassettes in which engagement of the handle of the tray by the end effector of a robot arm occurs without requiring any moving parts in either the end effector on the robot arm or the handle of the apparatus.
It is an additional objective of the invention to provide a carriage that is flexible in that it can accommodate several standard sizes of semiconductor material cassettes.
It is a still further objective of the invention to provide a carriage for transporting semiconductor material cassettes that permits such cassettes to be transported by automated equipment or manually without direct physical contact with the cassettes by such automated equipment or hands.
These and other objects of the invention will become more apparent in the following detailed description of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an isometric pictorial view of the carriage of the present invention.
FIG. 2 is an isometric pictorial view of the picker means used with the carriage of the present invention, with part of a robot arm shown in phantom dashed lines.
FIG. 3 is a partial isometric view of the upper part of the carriage with the carriage handle and the picker means shown engaged.
FIG. 3a is a detailed pictorial view very greatly enlarged showing contact points between the picker means and carriage handle, taken from the area encircled by 3a in FIG. 3.
FIG. 4 is a perspective view of the carriage of the invention with two semiconductor material cassettes of different sizes placed on the supporting surfaces with some parts shown in phantom dashed lines.
FIG. 5 is a sectional elevation taken along line 5--5 of FIG. 3.
FIG. 6 is a sectional elevation taken along line 6--6 of FIG. 3.
DESCRIPTION OF THE PREFERRED EMBODIMENT
As may be seen in FIG. 1, the carriage 10 of the present invention generally comprises a horizontal tray 20 to which is connected a handle neck 60 extending vertically upward from the center of the tray 20. A handle crosspiece 70 is attached to the upper end of the handle neck 60. The tray 20 incorporates at least one, preferably two wafer cassette stations, shown at 22 and 122 in FIG. 1. In the preferred embodiment, each of these wafer cassette stations 22, and 122 have the same structure and each is able to accommodate cassettes of various sizes that carry semiconductor materials such as silicon wafers. In the following, wafer cassette station 22 will be described. Its structure is symmetrically identical to that of wafer cassette station 122. This symmetry is indicated by comparable drawing numbers, e.g., support surface 23 at wafer cassette station 22 corresponding to support surface 123 at wafer cassette station 122.
Wafer cassette station 22 comprises a support surface 23 that is generally rectangular and bounded by a pair of parallel transverse cassette guides, exterior cassette guide 30 and interior cassette guide 32. Oriented at right angles to the transverse cassette guides 30 and, 32 is a pair of outer longitudinal cassette guides 40, 40 recessed slightly from the outer longitudinal edges of the tray 20. Located parallel to and between the outer longitudinal cassette guides 40, 40 is a pair of inner longitudinal cassette guides 42, 42.
Because the carriage 10 is to be used in connection with processing steps involving liquids, drainage of the wafer cassette station 22 is provided by an elongated opening 50 in the center of the support surface 23, as well as smaller drainholes 52 located in rows between the inner longitudinal cassette guides 42, 42 and the outer longitudinal cassette guides 40, 40. These openings also help reduce the weight of the carriage 10, thereby decreasing demands on any automated equipment that must lift or move the carriage 10.
The handle neck 60 extending vertically upward from the center of the tray 20 is formed by a pair of parallel neck members 62, and 63 in spaced relation to each other. These are attached to the tray 20 by screws or other suitable fasteners (not shown), made preferably from the same material as the tray 20. A buttress 64 is attached to each of the neck members 62, and 63 for additional support of the neck members 62, and 63. The buttresses 64, 64 are connected to the tray 20 in a manner similar to the neck members 62, and 63. Each buttress 64 has an opening through it to reduce weight.
At the upper end of the neck members 62, and 63 is a handle crosspiece 70. This consists of a pair of crossbars 72, and 73 with a spacer 74 located between them. The crossbars 72, and 73 are preferably molded as part of the respective handle neck members 62, and 63 to which they are connected. This facilitates the introduction of fillets 81, 81 located at the right angle connection points between handle neck member 63 and its corresponding crossbar 73, as well as between handle neck member 62 and its corresponding crossbar 72 (the latter fillets are not visible in FIG. 1). Spacer 74 is held in position by a suitable fastener, made preferably from the same material as the tray 20 and neck members 62, and 63.
As best seen in FIG. 4, each of the wafer cassette stations 22, 122 can accommodate a wafer cassette, such as large wafer cassette 24 shown in FIG. 4 at cassette station 22 or smaller wafer cassette 124 shown at cassette station 122. The wafer cassettes 24, and 124 come in a variety of standard sizes as described in "Book of Semi Standards 1985", published by Semiconductor Equipment and Materials Institute, Incorporated, Mountain View, Calif. These standards describe three-inch, four-inch, five-inch and six-inch wafer carriers or cassettes, named for the nominal size of the wafers accommodated by the cassettes. In FIG. 4, large wafers 25 are shown in large wafer cassette 24, while smaller wafers 125 are shown in smaller wafer cassette 124. The supporting surfaces 23, and 123 are sized so that they can accommodate more than one cassette size; preferably, they can handle three-inch, four-inch, five-inch and six-inch wafer cassettes.
As best seen at cassette station 22 in FIG. 4, the side wall 27 and the end wall 26 of the base of the wafer cassette 24 are confined by the outer longitudinal cassette guides 40, 40 and the outer and inner transverse cassette guides 30, and 32, respectively. In the case of a larger wafer cassette 24, the base of the cassette 24 occupies most of the supporting surface 23 and there is little room for lateral or longitudinal motion of the cassette 24. If such motion occurs, it is limited by the presence of the various cassette guides. The inner transverse cassette guide 32 maintains the cassette 24 in spaced relation to the handle cross piece 70 and buttresses 64, 64 so that both the inner and the outer ends of the cassette 24 may be grasped by hand or by automated equipment.
FIG. 4 shows the manner in which a smaller wafer cassette 124 is also confined by outer and inner transverse cassette guides 130, and 132 and outer longitudinal cassette guides 140, 140, although a greater portion of the supporting surface 123 is left exposed. In the case of a smaller wafer cassette 124, the presence of the inner longitudinal cassette guides 142, 142 also aids stable holding of the wafer cassette 124, as these limit skewing of the wafer cassette 124 to the extent that it has freedom to rotate on the support surface 123.
Turning now to FIGS. 2, 3, 3a, 5 and 6, the manner in which the handle crosspiece 70 and handle neck 60 are engaged or grasped by automated equipment is described. FIG. 2 shows a picker 90 used as the end effector of a robot arm 92. The picker 90 includes a picker mount 91 that has clamping set screws 100 and alignment abutment screws 102 at either end for attachment to and alignment on the robot arm 92. Extending from the picker mount 91 is a pair of lift fingers 94. Each of these has an upper face 95 with sloping sides 96, and 97 forming a capture groove. In addition, the interior leading surface of each lift finger 94 includes a rounded corner 98.
Turning specifically to FIGS. 3, 3a, 5 and 6, the engagement relationship between the picker 90 and the handle neck 60 together with the handle crosspiece 70 can be seen. The lift fingers 94 of the picker 90 straddle the handle neck 60 with the lift fingers 94 oriented at right angles to the handle crosspiece 70. The sloping sides 96, and 97 associated with the upper face 95 of each finger 94 help to guide the handle crossbars 72, and 73 into stable engagement with the upper faces 95 of the fingers 94. Centering of the handle neck 60 between the lift fingers 94 is initially facilitated by the rounded corners 98 and later by the fillets 81 on either side of the handle neck 60. FIGS. 5 and 6 show the final engaged position of the picker 90 and the handle neck 60 and handle crosspiece 70. In this position, there is stable, surface-to-surface contact between the upper faces 95 of the lift fingers 94 meeting the lower surfaces of the crossbars 72, and 73. Also, the outer edges of the fillets 81 of handle neck members 62, and 63 are engaged by the internal upper edges of the lift fingers 94. Because the lower surfaces of the crossbars 72, and 73 are substantially parallel to the plane of the tray 20, when upper surfaces 95, 95 of the fingers 94, 94 are horizontal, the tray 20 is held horizontal. In this position, the picker 90, driven by the robot arm 92, can lift and move the carriage 10. To the extent that lifting or other motion causes movement of the carried wafer cassettes 24 or 124, this movement is limited by the various cassette guides discussed above. The crossbar structure with flat engagement surfaces also reduces possible adverse effects from wafer cassettes of unequal weight.
The carriage 10 of the present invention is preferably made from a temperature-resistant plastic such as "Teflon PFA," a perfluoroalkoxy-substituted polytetrafluoroethylene resin, molded in two or more pieces and connected by fasteners made of the same material. Alternatively, for certain designs the entire carriage 10 could be molded as a unit.
In summary, it will be seen from the above that the present invention comprises an apparatus useful for the transport of semiconductor wafer cassettes during processing. The wafer cassettes are stably held and confined at one or more wafer cassette stations 22, or 122 on a tray 20. The handle neck 60 and handle crosspiece 70 of the carriage 10 can be engaged by a picker 90 that has no moving parts that open or close for engagement. Because of its own construction and the complementary construction of the handle neck and handle crosspiece, the picker 90 will center itself into stable engagement even if the robot is not precise in its approach to the carriage 10. The carriage is flexible because it can hold different sizes of wafer cassettes, including more than one size at once.
While a preferred embodiment of the invention has been illustrated and described, it is to be understood that the invention is not limited to the precise apparatus herein disclosed, and the right is reserved to all variations coming within the scope of the appended claims. For example, it will be clear that the invention could involve support surfaces of varying shapes and various different constructions for the handle neck and handle crosspiece. Designs with a single cassette station or more than two cassette stations are also possible. In addition, in the embodiment shown material could be removed from a variety of other members to facilitate drainage and/or to reduce the total weight of the carriage. Finally, while a preferred material for the carriage has been specified, other materials suitable for the work environment and the required degree of rigidity can be found. | An apparatus for holding and transporting semiconductor material cassettes during processing of the semiconductor material. There is a tray having at least one cassette station thereon. This cassette station comprises a cassette supporting surface, a first pair of substantially parallel cassette guides on the supporting surface, and a second pair of substantially parallel cassette guides on the supporting surface located between and substantially at right angles to the first pair. The first and second pairs of parallel cassette guides form a generally rectangular boundary. A handle neck extends upwardly from the same side of the tray as the cassette guides. A handle crosspiece is connected to the handle neck and has a bearing surface oriented substantially parallel to the plane of the tray. A picker is also disclosed for engaging the handle neck and handle crosspiece, and can be used as the end effector of a robot arm that provides lifting power and transport motion. | 8 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to nylon copolymer compositions and to multilayered film structures made therefrom. More particularly, the invention pertains to coextruded films having at least one polyamide copolymer layer attached to at least one olefin containing polymer layer by means of an optional adhesive composition therebetween. Such structures are suitable for use as barrier films, such as aroma barrier films, which have reduced curl. The nylon compositions are extremely uniform, and have only a single melting point rather than individual melting points of the component nylon copolymer parts.
2. Description of the Prior Art
It is known in the art to prepare blends of nylon polymers. Melt blending of N6 and N66 under commercial processing conditions leads to non-homogenous products with two separate phases as indicated by their individual characteristic melting points. It is well known to prepare copolymers of N6 with other polyamides such as nylon 66, nylon 11, nylon 12, nylon 6T, nylon 46, etc. It has now been unexpectedly found that when blends are formed from two different nylon copolymers, each containing either nylon 6 or nylon 66, in certain proportions, that homogenous, super-miscible blends are formed having improved properties. Films produced from dual nylon copolymer compositions, when attached to polyolefin films produce multilayered structures having unexpectedly reduced curl.
U.S. Pat. No. 5,206,309 teaches heat stable films based on melt blends of N6 and N6/N66. U.S. Pat. Nos. 5,053,259 and 5,344,679 teach blends of an amorphous nylon, a copolyamide, and optionally a polyamide homopolymer. U.S. Pat. No. 4,877,684 claims films based on mixtures of nylon 6 and N6/N66. EP Patent 408,390 discloses the use of any polyamide, any copolyamide, or a mixture of polyamides along with amorphous polyamide or a copolyamide. Japanese patent 115,4752 discloses films based on mixtures of an aliphatic polyamide and a partially aromatic amorphous polyamide along with EVOH. AU Patent 8825700 discloses an aliphatic polyamide, e.g., nylon 6 or N6/66 copolymer and an amorphous polyamide. All of these do not teach random copolymers of nylons in certain proportions to form a homogenous, miscible phase composition according to the invention. U.S. Pat. Nos. 4,647,483; 4,665,135 and 4,683,170, show blends of N6 plus a copolymer of N6/N66 or N6/N 12 rich in N6. A film that is formed from a blend of a polyamide and a polyolefin is described in U.S. Pat. No. 4,444,829.
It would be desirable to provide super-miscible blends of semi-crystalline nylon copolymers where each have a nylon 6 or nylon 66 moiety.
SUMMARY OF THE INVENTION
The invention provides a nylon composition which comprises a substantially uniform blend of at least one semi-crystalline copolymer I and at least one semi-crystalline copolymer II, wherein the proportion by weight of each of copolymer I and copolymer II is such that the composition has only one significant melting point; wherein
(a) copolymer I is a copolymer of a semi-crystalline nylon A and a semi-crystalline different nylon B wherein nylon A is present in copolymer I in an amount of from about 70 percent to about 95 percent by weight and nylon B is present in copolymer I in an amount of from about 5 percent to about 30 percent by weight of copolymer I; and
(b) copolymer II is a copolymer of semi-crystalline nylon A and at least one different semi-crystalline nylon C wherein nylon A is present in copolymer II in an amount of from about 40 percent to about 95 percent by weight and nylon C is present in copolymer II in an amount of from about 5 percent to about 60 percent by weight of copolymer II; and
(c) wherein nylon A and nylon B are selected from the group consisting of nylon 6 and nylon 66; and
(d) wherein nylon C is selected from the group consisting of nylon 9, nylon 11, nylon 12, nylon 46 and nylon 69.
The invention also provides a method for producing a substantially uniform nylon composition which comprises:
(i) forming a mixture of solid particles of at least one semi-crystalline copolymer I and at least one semi-crystalline copolymer II, wherein the proportion by weight of each of copolymer I and copolymer II is such that the composition has only one significant melting point; wherein and wherein copolymer I and copolymer II are as defined above; and
(ii) melt blending the mixture at a temperature of at least the higher of the melting points of copolymer I or copolymer II.
The invention further provides a multilayered film structure which comprises at least one nylon composition film layer attached to at least one olefin containing polymer film layer, wherein the nylon composition film layer comprises a substantially uniform blend of at least one semi-crystalline copolymer I and at least one semi-crystalline copolymer II, wherein the proportion by weight of each of copolymer I and copolymer II is such that the composition has only one significant melting point; wherein copolymer I and copolymer II are as defined above.
The invention still further provides method for preparing a multilayered film structure which comprises coextruding a molten nylon composition film layer and a molten polyolefin layer attached onto at least one side of the nylon composition film layer, through a coextrusion die, wherein the polyolefin layer comprises at least one olefin containing polymer; wherein the nylon composition film layer comprises a substantially uniform blend of at least one semi-crystalline copolymer I and at least one semi-crystalline copolymer II, wherein the proportion by weight of each of copolymer I and copolymer II is such that the composition has only one significant melting point; wherein copolymer I and copolymer II are as defined above.
Such copolymers have improved anti-curling properties and a single melting point. According to this invention, nylon copolymers can be incorporated into a miscible blend in such a way that the resulting product is a one-component, homogenous material. The products of this invention are different from conventional blends in view of having only one melting point. The invention, in addition, allows one to incorporate multi-component copolyamides together with amorphous nylons, without observing non-homogeneity.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a graph of the melting pattern of copolymer blended films.
FIG. 2 shows a graph of the melting pattern of other copolymer blended films.
FIG. 3 shows a graph of the melting pattern of other copolymer blended films.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
In the practice of the present invention, a composition is prepared by melt blending at least one semi-crystalline copolymer which is a copolymer of a nylon A with a different nylon B, plus at least one semi-crystalline nylon copolymer which is a copolymer of nylon A with a different nylon C. The composition optionally also comprises a non-crystalline amorphous nylon copolymer D. The formed composition is determined to have only a single significant melting point. For purposes of this invention, having only a single significant point means that a second melting point, if one is observed, is no more than 35% of the main melting peak, more preferably no more than 20% of the main melting peak and most preferably no more than 10% of the main melting peak. The intensity of the second melting peak, if observed, is determined by known DSC methods. Such methods include analyzing a film to be tested after drying at 25° C.-45° C. under vacuum for several hours. The intensity of the major and any minor peaks in DSC are determined by heat of fusion integrated over the melting ranges of the individual peaks. Preferably the composition has only one melting point and no other melting point at all.
The first component of the inventive composition is a semi-crystalline copolymer of nylon A with a different nylon B. Each of nylon A and nylon B may be either nylon 6 or nylon 66. Nylon 6 is also known as poly(caprolactam) and nylon 66 is also known as poly(hexamethylene adipamide).
The second component of the inventive composition is a semi-crystalline nylon copolymer which is a copolymer of nylon A plus at least one different nylon C which may be nylon 9-poly(9-aminononanoic acid), nylon 11-poly(11-aminoundecanoic acid), nylon 12-poly(12-aminododecanoic acid), nylon 46 or nylon 69.
The number average molecular weight of the nylon A/nylon B copolymer as well as the nylon A/nylon C copolymer may vary widely. Such are sufficiently high to form a free standing film but sufficiently low to allow melt processing of the blend. Such number average molecular weights are well known to those of skill in the film forming art and are usually at least about 5,000 as determined by the formic acid viscosity (FAV) method (ASTM D-789). In this method, a solution of 11 grams of aliphatic polyamide in 100 ml of 90% formic acid at 25° C. is used. In the preferred embodiments of the invention, the number average molecular weight of nylon A as well as the nylon A/nylon B ranges from about 5,000 to about 100,000, preferable from about 10,000 to about 60,000 and more preferably from about 20,000 to about 40,000.
The nylon composition may further contain an optional non-crystalline, non-crystallizable, amorphous nylon component D. Amorphous nylons are well known in the art and are available commercially. Amorphous nylons are typically prepared by the reaction of at least one diamine with at least two different diacids. The result is a non-homogeneous nylon having no determinable melting point. Amorphous nylons are available as Grivory 21 available from EMS of Switzerland and Zytel amorphous nylon from DuPont.
The proportion by weight of each of copolymer I and copolymer II is such that the composition has only one significant melting point. Preferably the amount of copolymer I ranges from about 75% to about 95% and the amount of copolymer II ranges from about 5% to about 25% based on the weight of the composition. More preferably the amount of copolymer I ranges from about 90% to about 93% and the amount of copolymer II ranges from about 7% to about 10% based on the weight of the composition.
Nylon A is preferably present in copolymer I in an amount of from about 70 percent to about 95 percent by weight and nylon B is preferably present in copolymer I in an amount of from about 5 percent to about 30 percent by weight of copolymer I. More preferably the amount of nylon A in copolymer I ranges from about 75% to about 90% and the amount of nylon B ranges from about 10% to about 25% by weight of copolymer I. Most preferably the amount of nylon A in copolymer I ranges from about 80% to about 85% and the amount of nylon B ranges from about 15% to about 20% by weight of copolymer I.
Nylon A is preferably present in copolymer II in an amount of from about percent to about 95 percent by weight and nylon C is preferably present in copolymer II in an amount of from about 5 percent to about 60 percent by weight of copolymer II. More preferably the amount of nylon A in copolymer II ranges from about 50% to about 80% and the amount of nylon C ranges from about 30% to about 50% by weight of copolymer II. Most preferably the amount of nylon A in copolymer II ranges from about 50% to about 65% and the amount of nylon C ranges from about 35% to about 50% by weight of copolymer II.
When an amorphous nylon is included in the composition, it is present in the overall composition an amount of from about 1% to about 5%, preferably from about 2% to about 4% and more preferably from about 2% to about 3% based on the weight of the nylon composition.
The nylon composition may be formed by dry blending solid particles or pellets of each of the nylon components and then melt blending the mixture at a temperature of at least the melting point of the higher melting point component. Typical melting temperatures range from about 175° C. to about 260° C., preferably from about 215° C. to about 225° C., and more preferably from about 220° C. to about 223° C. Blending may take place in any suitable vessel such as an extruder, a roll mixer, or the like. Blending is conducted for a period of time required to attain a substantially uniform blend. Such may easily be determined by those skilled in the art. If desired, the composition may be cooled and cut into pellets for further processing, or it may be formed into films and optionally uniaxially or biaxially stretched by means well known in the art.
In the practice of the present invention, a multilayered film is prepared which is broadly composed of the nylon copolymer composition layer and a polyolefin layer attached to at least one side of the nylon layer by an optional adhesive. The adhesive preferably comprises at least one polyolefin having at least one functional moiety of an unsaturated carboxylic acid or anhydride thereof.
The polyolefins used herein include polymers of alpha-olefin monomers having from about 2 to about 6 carbon atoms and includes homopolymers, copolymers (including graft copolymers), and terpolymers of alpha-olefins. Illustrative homopolymer examples include ultra low density (ULDPE), low density (LDPE), linear low density (LLDPE), medium density (MDPE), or high density polyethylene (HDPE); polypropylene; polybutylene; polybutene-1; poly-3-methylbutene-1; poly-pentene-1; poly-4-methylpentene-1; polyisobutylene; and polyhexene.
Polyolefins such as polyethylenes are commonly differentiated based on the density which results from their numbers of chain branches per 1,000 carbon atoms in the polyethylene main chain in the molecular structure. Branches typically are C 3 -C 8 olefins, and which are preferably butene, hexene or octene. For example, HDPE has very low numbers of short chain branches (less than 20 per 1,000 carbon atoms), resulting in a relatively high density, i.e. density ranges from about 0.94 gm/cc to about 0.97 gm/cc. LLDPE has more short chain branches, in the range of 20 to 60 per 1,000 carbon atoms with a density of about 0.91 to about 0.93 gm/cc. LDPE with a density of about 0.91 to about 0.93 gm/cc has long chain branches (20-40 per 1,000 carbon atoms) instead of short chain branches in LLDPE and HDPE. ULDPE has a higher concentration of short chain branches than LLDPE and HDPE, i.e. in the range of about 80 to about 250 per 1,000 carbon atoms and has a density of from about 0.88 to about 0.91 gm/cc. Illustrative copolymer and terpolymers include copolymers and terpolymers of alpha-olefins with other olefins such as ethylene-propylene copolymers; ethylene-butene copolymers; ethylene-pentene copolymers; ethylene-hexene copolymers; and ethylene-propylene-diene copolymers (EPDM). The term polyolefin as used herein also includes acrylonitrilebutadiene-styrene (ABS) polymers, copolymers with vinyl acetate, acrylates and methacrylates and the like. Preferred polyolefins are those prepared from alpha-olefins, most preferably ethylene polymers, copolymers, and terpolymers. The above polyolefins may be obtained by any known process. The polyolefin may have a weight average molecular weight of about 1,000 to about 1,000,000, and preferably about 10,000 to about 500,000. Preferred polyolefins are polyethylene, polypropylene, polybutylene and copolymers, and blends thereof. The most preferred polyolefin is polyethylene.
In accordance with the present invention, suitable adhesives include modified polyolefin compositions composed of a polyolefin having at least one functional moiety of unsaturated polycarboxylic acids and anhydrides thereof. Polyolefins include any of those listed above.
Unsaturated carboxylic acid and anhydrides include maleic acid and anhydride, fumaric acid and anhydride, crotonic acid and anhydride, citraconic acid and anhydride, itaconic acid an anhydride and the like. Of these, the most preferred is maleic anhydride. The modified polyolefins suitable for use in this invention include compositions described in U.S. Pat. Nos. 3,481,910; 3,480,580; 4,612,155 and 4,751,270 which are incorporated herein by reference. The most preferred adhesive is a maleic anhydride modified ethylene -olefin copolymer which is also known as linear ultra low density polyethylene. The preferred modified polyolefin composition comprises from about 0.001 and about 10 weight percent of the functional moiety, based on the total weight of the modified polyolefin. More preferably the functional moiety comprises from about 0.005 and about 5 weight percent, and most preferably from about 0.01 and about 2 weight percent. The modified polyolefin composition may also contain up to about 40 weight percent of thermoplastic elastomers and alkyl esters as described in U.S. Pat. No. 5,139,878. The most preferred adhesive is Flexomer 1373 from Union Carbide which is a 10% maleic anhydride modified copolymer of ethylene and butene.
Each layer of the multilayer film structure can contain additives which are conventionally used in such films. Examples of such additives are pigments, dyes, slip additives, fillers, nucleating agents, plasticizers, lubricants, reinforcing agents, antiblocking agents, stabilizers and inhibitors of oxidation, thermal stabilizers and ultraviolet light stabilizers. Preferably, such may be present in an amount of about 10% or less based on the weight of the layer.
The multilayer films of this invention may be produced by conventional methods useful in producing multilayer films, including coextrusion, blown film and extrusion lamination techniques. In the most preferred method, the film is formed by coextrusion. Melted and plasticated streams of the polyamide and polyolefin layer materials are fed into a co-extrusion die. While in the die, the layers are juxtaposed and combined, then emerge from the die as a single multiple layer film of polymeric material. Suitable coextrusion techniques are more fully described in U.S. Pat. Nos. 5,139,878 and 4,677,017 except coextrusion in this invention is conducted at from about 460° F. (238° C.) to about 510° F. (266° C.). Coextrusion techniques include methods which include the use of a feed block with a standard die, a multimanifold die such as a circular die, as well as a multimanifold die such as used in forming multilayer films for forming flat cast films and cast sheets. Alternatively the composition may be formed into a film using a conventional blown film apparatus.
An advantage of coextruded films is the formation of a multilayer film in a one process step by combining molten layers of each of the film layers of polyamide and polyolefin blend into a unitary film structure. Preferably the multilayers form an inseparable bond with one another. The term "inseparable bond" as used herein shall mean a bond strength of at least about 700 g/inch as determined by testing the film according to the procedure set forth in ASTM D-3359-90 and F88-85.
In order to produce a multilayer film by a coextrusion process, it is necessary that the constituents used to form each of the individual films be compatible with the film extrusion process. The term "compatible" in this respect means that the film-forming compositions used to form the films have melt properties which are sufficiently similar so as to allow coextrusion. Melt properties of interest include, for example, melting points, melt flow indices, apparent viscosity, as well as melt stability. It is important that such compatibility be present to assure the production of a multilayer film having good adhesion and relatively uniform thickness across the width of the film being produced. As is known in the art, film-forming compositions which are not sufficiently compatible to be useful in a coextrusion process frequently produce films having poor interfacial lamination, poor physical properties as well as poor appearance. One skilled in the art can readily weigh the above-noted compatibility in order to select polymers having desirable physical properties and determine the optimal combination of relative properties in adjacent layers without undue experimentation. If a coextrusion process is used, it is important that the constituents used to form the multilayer film be compatible within a relatively close temperature range in order to permit extrusion through a common die. In the preferred embodiment when the nylon has a formic acid viscosity FAV of from about 120 to about 250 by ASTM D-789 and the polyolefin layer has a melt index of from about 0.5 to about 3 melt index units (MI) as determined by ASTM D-1238, the films will be compatible. That is, the nylon and polyolefin layers will flow uniformly in the coextruder. The multilayered structure may have two, three or more layers of alternating nylon and polyolefin layers with the optional adhesive intermediate each layer.
Alternatively, the multilayer films of the present invention can be produced by lamination whereby a multilayer film structure is formed from pre-fabricated film plies by methods which are well known in the art. The basic methods used in film laminating techniques are fusion, wet combining, and heat reactivating. Fusion, which is a method of laminating two or more film plies using heat and pressure laminated are comprised of polymers that readily form interfacial adhesion. Wet combining and heat reactivating are utilized in laminating incompatible films using adhesive materials. Typically, laminating is done by positioning the individual layers of the inventive film on one another under conditions of sufficient heat and pressure to cause the layers to combine into a unitary film. Typically the polyolefin and polyamide layers are positioned on one another, and the combination is passed through the nip of a pair of heated laminating rollers by techniques well known in the art such as those described in U.S. Pat. No. 3,355,347. Lamination heating may be done at temperatures ranging from about 75° C. to about 175° C., at pressures ranging from about 5 psig (0.034 MPa) to about 100 psig (0.69 MPa) for from about 5 seconds to about 5 minutes, preferably from about 30 seconds to about 1 minute.
The multilayer film, whether comprising a two, three or more layer structure, may be stretched or oriented in any desired direction using methods well known to those skilled in the art. Examples of such methods include those set forth in U.S. Pat. No. 4,510,301. Optionally, the film may be stretched uniaxially in either the direction coincident with the direction of movement of the film being withdrawn from the film forming apparatus, also referred to in the art as the "machine direction", or in as direction which is perpendicular to the machine direction, and referred to in the art as the "transverse direction", or biaxially in both the machine direction and the transverse direction. The films of the present invention have sufficient dimensional stability to be stretched at least 1.5 and preferably more than three times and more preferably from more than three times to about ten times in either the machine direction or the transverse direction or both. Typically for use in the present invention, the oriented film formed from the composition of the invention are preferably produced at draw ratios of from about 1.5:1 to about 6:1, and preferably at a draw ratio of from about 3:1 to about 4:1. The term "draw ratio" as used herein indicates the increase of dimension in the direction of the draw. Therefore, a film having a draw ratio of 2:1 has its length doubled during the drawing process. Generally, the film is drawn by passing it over a series of preheating and heating rolls. The heated film moves through a set of nip rolls downstream at a faster rate than the film entering the nip rolls at an upstream location. The change of rate is compensated for by stretching in the film.
Although each layer of the multilayer film structure may have a different thickness, the total thickness of the multilayered structure preferably ranges from about 0.3 mils (7.6 μm) to about 5.0 mils (127.0 μm) and preferably from about 0.5 mils (12.7 μm) to about 1.5 mils (37.5 μm). While such thicknesses are preferred as providing a readily flexible film, it is to be understood that other film thicknesses may be produced to satisfy a particular need and yet fall within the scope of the present invention.
The following non-limiting examples serve to illustrate the invention.
EXAMPLES
The starting polymers used were analyzed by Gas Chromatography (GC) using standard procedures. The precision of these measurements is ±2%. The films were analyzed by Differential Scanning Calorimetry (DSC) using a Seiko RDC-220 thermal analyzer, equipped with a robotics system. About 7.5 (±0.5) mg of the film sample was crimped in an aluminum pan, heated from room temperature to about 280° C. at a heating rate of 10° C./min., and held there to erase crystalline memory. Subsequently, the sample was cooled from 280° C. to room temperature at a cooling rate of 10° C. and then reheated at the same rate. The T m reported in the examples is the one obtained upon initial heating cycle, i.e., corresponding to the "as--received films" cast under the same conditions. All grades of nylons used in this study are readily commercially available.
Example 1
This example prepares physical blends of a copolymer of nylon 6/nylon 66 with a copolymer of nylon 6/nylon 12. Dried pellets of 50% nylon 6 (85)/nylon 66(15) and 50% nylon 6(81)/nylon 12(19) copolymers were physically mixed in the weight percents indicated in Table 1. The compositions were dried at 82° C. for about 18 hours and then extruded through a Killion single screw extruder (D=1.5 in; L/D=24/1) equipped with three heating zones (232° C., 257° C. and 260° C.) and two adapters (260° C.). The melt temperature was measured as 267° C. After passing through an extrusion film die maintained at 260° C., the extrudate was cast on a roll maintained at 82° C. followed by a cooling roll maintained at 43° C. The resultant film had a total thickness of about 2 mil.
TABLE 1______________________________________Film # Film Description Tm, ° C.______________________________________1 100% N6(85)/N66(15) (control) 196.72 50% N6(85)/N66(15) Copolymer 198.0 50% N6(81)/N12(19) Copolymer3 100% N6(81)/N12(19) Copolymer 203.5 (control)______________________________________
The melting patterns of each film are plotted in FIG. 1. These data show that physical mixtures of a nylon 6/66 copolymers and a nylon 6/12 copolymer according to the invention (film 2) yields a composition having only one detectable melting point. It is clear that the blend according to the invention is homogenous and miscible in the crystalline phase, as evident by a single T m . These data are shown in FIG. 1.
Example 2
This example prepares physical blends of a copolymer of nylon 6/nylon 66 with a copolymer of nylon 6/nylon 12. Dried pellets of nylon 6(85)/nylon 66(15) and nylon 6(50)/nylon 12(50) copolymers were physically mixed in the weight percents indicated in Table 2. The compositions were dried at 82° C. for about 18 hours and then extruded through a Killion single screw extruder (D=15 in; L/D=24/1) equipped with three heating zones (232° C., 257° C. and 260° C.) and two adapters (260° C.). The melt temperature was measured as 267° C. After passing through an extrusion film die maintained at 260° C., the extrudate was cast on a roll maintained at 82° C. followed by a cooling roll maintained at 43° C. The resultant film had a total thickness of about 2 mil.
TABLE 2______________________________________Film # Film Description Tm, ° C.______________________________________1 100% N6(85)/N66(15) (control) 196.72 75% N6(85)/N66(15) Copolymer 195.3 25% N6(50)/N12(50) Copolymer3 100% N6(50)/N12(50) Copolymer 132.0 (control)______________________________________
The melting patterns of each film are shown in FIG. 2. These data show that physical mixtures of a nylon 6/66 copolymers and a nylon 6/12 copolymer according to the invention (film 2) yield a composition having only one detectable melting point. It is clear that the blend according to the invention is homogenous and miscible in the crystalline phase, as evident by a single T m . These data are exhibited in FIG. 2.
Example 3
This example prepares physical blends of copolymers nylon 6 and nylon 66 in varying proportions. Dried pellets of nylon 6 (85)/nylon 66(15) and nylon 6(50)/nylon 69(50) copolymers were physically mixed in the weight percents indicated in Table 3. The compositions were dried at 82° C. for about 18 hours and then extruded through a Killion single screw extruder (D=1.5 in; L/D=24/1) equipped with three heating zones (232° C., 257° C. and 260° C.) and two adapters (260° C.). The melt temperature was measured as 267° C. After passing through an extrusion film die maintained at 260° C., the extrudate was cast on a roll maintained at 82° C. followed by a cooling roll maintained at 43° C. The resultant film had a total thickness of about 2 mil.
TABLE 3______________________________________Film # Film Description Tm, ° C.______________________________________1 100% N6(85)/N66(15) (control) 196.72 95% N6(85)/N66(15) Copolymer 196.8 5% N6(50)/N66(50) Copolymer3 90% N6(85)/N66(15) Copolymer 196.7 10% N6(50)/N69(50) Copolymer4 75% N6(85)/N66(15) Copolymer 195.4 and 128 25% N6(50)/N69(50) Copolymer5 100% N6(50)/N69(50) Copolymer 129.0 and 139.6 (control)______________________________________
The melting patterns of each film are shown in FIG. 3. These data show that physical mixtures of two nylon copolymers according to the invention (films 2 and 3) yield a composition having only one detectable melting point. By increasing the amount of copolymer II to 25% (Film 4) a single significant melting point is detected as well as a trivial melting point at 128° C. It is clear that the blends according to the invention are homogenous and miscible in the crystalline phase, as evident by a single T m . These data are shown in FIG. 3.
It is clear that the blends according to the invention are homogenous and miscible in the crystalline phase as evidenced by their single significant melting points. Examples 1-3 show that the two copolymers can be blended in any proportion as long as only one or predominantly one melting peak is observed, i.e. the mixed composition fulfills the criteria for super-miscibility.
Example 4
A three extruder system is constructed of 3.2 cm (11/4",) Killion single screw extruders (two with L/D=24/1, and the other with L/D=30/1).
Dried pellets of 50% nylon 6 (85)/nylon 66(15) and 50% nylon 6(81)/nylon 12(19) copolymers are physically mixed and fed into the extruder with L/D=30/1 with an extrusion profile set at 232° C., 254° C., and 260° C. for the heating zones 1-3 and 260° C. for the adapters. The melt temperature is measured at 257° C. A maleic anhydride modified polyolefin tie resin (density: 0.88 gm/cc, melt index: 1.0 gm/10 min. at 190° C. is extruded through a 3.2 cm (11/4") diameter Killion single screw extruder L/D=24/1 equipped with four heating zones and two adapters. The extruder temperature profiles are set at 238° C., 249° C., 260° C., 266° C. for the zone 1-4 and the adapters are maintained at 266° C. The resulting melt temperature is 263° C. Polyethylene is extruded in the extruder with L/D=24/1 with an extrusion profile set at 238° C., 252° C., 257° C., and 260° C. for the heating zone 1-4 and 260° C. for the adapters. The melt temperature is measured at 260° C. The extrudates, after passing through a coextrusion film die kept at 260° C., is then cast on a roll maintained at 38° C., followed by a cooling roll set at 35° C. The resultant film has a thickness of 25 μm. The polyethylenes used are: LDPE: low density PE-density=0.919, melt index=0.65; LLDPE: linear low density PE-density=0.920, melt index=l; MDPE: medium density PE-density=0.941, melt index=4; HDPE: high density PE-density=0.954, melt index=6. The films are exposed to the environment without restraints. No edge curl is noticed from any film. It can be seen from the foregoing that that the invention provides films having excellent curl resisting properties.
Example 5
Example 4 is repeated except the nylon used is nylon 6 homopolymer. Significant edge curl is noticed from the multilayered film produced.
Example 6
Example 4 is repeated except the nylon used is nylon 66 homopolymer. Significant edge curl is noticed from the multilayered film produced.
Example 7
Example 4 is repeated except the nylon used is N6(85)/N66(15) copolymer. Significant edge curl is noticed from the multilayered film produced.
Example 8
Example 4 is repeated except the nylon used additionally contains 2% of amorphous nylon. No significant edge curl is noticed from the multilayered film produced. | Super-miscible blends of nylon copolymers are provided as well as multilayered film structures made therefrom. A nylon composition is a substantially uniform blend of at least one semi-crystalline copolymer I and at least one semi-crystalline copolymer II, wherein the proportion by weight of each of copolymer I and copolymer II. The nylon compositions are extremely uniform, and have only a single melting point rather than individual melting points of the component nylon copolymer parts. Coextruded films of a layer of this nylon composition with an olefin containing polymer are suitable for use as barrier films, such as aroma barrier films, which have reduced curl. | 8 |
FIELD OF THE INVENTION
With the renewed and ever expanding interest in Stirling engines, efforts have been made to continually improve upon their design. Basic Stirling engine principals of operations are set forth in a text entitled, "Stirling Engines" by G. Walker, 1st Edition, 1980. Essentially, in this regard, a Stirling engine operates on the principal of heating and cooling a working fluid (gas), with the expansion and compression of the gas utilized to perform useful work. A variety of designs are illustrated in the aforenoted text with their attendant advantages.
A great many designs of Stirling engines utilize lighter-than-air gases such as hydrogen or helium as the working fuid due to their relatively high conductivity, lighter specific heat and lower viscosity. While the use of such gases has its advantages, an important requisite is to maintain a fixed inventory of the working gas, thus requiring that a sealed cycle is maintained.
As an alternative to the lighter gases, air has been used. A distinct advantage of an air-cycle Stirling engine as compared to the fixed inventory lighter than air engine is that of the nature of the sealing between the working spaces and ambient conditions. Current hydrogen and helium engines use a sliding seal on a rod between the pistons and crossheads.
Because of the clearance requirements of this arrangement, engine height and volume are penalized to accommodate it. Since an air cycle engine in an air environment would not need near perfect sealing because any leakage can be easily replaced from the environment, such an engine would not only avoid the elaborate sealing arrangements utilized but also could use the volume and weight saved by that avoidance to its advantage.
Heretofore, however, due to the poor transport and fluid properties of air, (i.e., lower conductivity, lower specific heat and higher viscosity), designs of Stirling engines utilizing air as a working fluid have not been entirely satisfactory. Attempts to compensate for relatively poor fluid properties, usually resulted in extremely large, inefficient engines having low power-to-weight ratio. While efficiencies in an air-cycle engine as compared to those engines utilizing the lighter gases has heretofore been possible, it has usually been realized only at low speeds and low specific power, thus limiting their applications.
SUMMARY OF THE INVENTION
Accordingly, it is a principal object of the present invention to provide for an air-cycle Stirling engine which is relatively efficient and capable of widespread application similar to that enjoyed by lighter-than-air cycle engines in high-speed, high power-density duty.
It is a further object of the present invention to provide for such an air-cycle Stirling engines, which is relatively simple in design and relatively inexpensive.
It is another object of the present invention to provide a Stirling engine which removes certain of the shortcomings of the lighter-than-air working fluid engines, particularly the rigid sealing requirements.
The present invention provides for an air-cycle Stirling engine which is a viable alternative to, for example, hydrogen or helium engines. In this regard, through the use of an improved heat exchanger design, the shortfalls of using air as a working fluid are overcome. Moreover, the present heat exchanger design allows an engine having a weight and volume comparable to e.g., hydrogen cycle engines, with however, a simpler, cheaper and more reliable construction.
In this regard, the present invention provides for a heat exchange module which integrates in a layered fashion the heater, regenerator and cooler about the combustion chamber as a compact and inexpensive unit. The particular heater tube construction, regenerator and cooler design allows for effective heat transfer in a compact situation necessary for an air-cycle engine while being relatively simple and inexpensive.
BRIEF DESCRIPTION OF THE DRAWINGS
Thus, by the present invention, the aforenoted objects and advantages and others will be realized, the description of which should be taken in conjunction with the drawings, wherein:
FIG. 1 is a side, partially sectional view of the Stirling engine incorporating the teachings of the present invention;
FIG. 2 is a top partially sectional view of the Stirling engine incorporating the teachings of the present invention;
FIG. 3 is a somewhat schematic representation illustrating the relationship between the heat exchange module and the expansion and compression pistons;
FIG. 4 is an exploded, partially sectional view of portions of the heat exchange module, incorporating the teachings of the present invention;
FIG. 4A is a sectional view of an assembled heating tube unit incorporating the teachings of the present invention;
FIG. 5 is an enlarged, partially sectional top view of a portion of the heat exchange module positioned within the Stirling engine;
FIG. 6 is a side partially sectional view looking toward the axis of the expansion piston of the Stirling engine; and
FIG. 7 is an enlarged side sectioal view of a portion of the heat exchange module positioned within the Stirling engine shown in FIG. 6.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
With more particular regard to the drawings, there is generally shown a Stirling cycle or engine 10 which is designed to utilize air as its working fluid. The engine includes an outer casing 12 in which is positioned a heat exchange module 14 which includes a heater tube matrix 16 comprised of individual heater tubes 18, a regenerator 20 and a cooler 22 successively positioned in a layered fashion about the combustion chamber 24, as shown in FIGS. 1 and 2.
The general relationship between the heat exchange module 14 and the compression (cold) and expansion (hot) pistons 26 and 28 respectively, which are part of the engine, can best be described with reference to FIG. 3. The pistons are shown on a common crank and are displaced spatially to cause the expansion piston 28 to lead the compression piston 26 by some angle (i.e. 90°). The cold compression piston 26 is coupled to a cold compression duct 29 and drives air through the heat exchange module 14 where it is heated. A hot connecting duct 30 communicates between the expansion space and a ring duct 31 which picks up the heated air from the heat exchange module 14. Piston 18 is driven by the heated air with the oscillating air flow back and forth generating work in accordance with well known Stirling engine principals.
The present invention minimizes the volume or space required for the components involved in the heat exchanger i.e., heating tubes, regenerator and cooler. In this regard and with reference to FIG. 4, the heater exchange module 14 is shown in an exploded view. The heater tube unit 32, made of highly thermally conductive material, includes a flared, blind ended, deep draw member 34 around which snugly fits a crenulated open ended tube 36 to form channels 38 therebetween. This in turn then snugly fits into a plain open ended tube 40 which forms channels 42. The assembly is then brazed into a single heater tube unit as shown in FIG. 4A. Since the unit is fully brazed, hoop stress is largely taken on the small effective passage diameter allowing thin walls and good thermal performance. The members 34-36 are relatively simple allowing for inexpensive production and assembly. Like the cooler (to be discussed), the heater needs many air passages which are shorter and finer than those heretofore utilized on the lighter gas engines.
The heater tube unit 32 is essentially an annular collection of gas passages or channels from space 44 to space 46 and back again with simple coaxial manifolds. Air entering at 48 would flow between members 36 and 38 via channels 42 to space 44 then reverse directions and flow down between 34 and 36 via channels 38 and out opening 50 of tube 36 and vice versa. The effective number of passages is determined by the number of crenulations on tube 36.
The heat transfer to the air flowing within the heater tube may be enhanced by finning or perhaps by adding a varied pitch fluted tube 52 about it so as to swirl the combustion gas in the channels formed therebetween which would exit as exhaust. FIG. 5 shows the optional use of such fluted tubes with the heater tube units 32. These tubes are positioned in openings in a cylindrical fiber ceramic manifold 53 in the combustion chamber 24 as shown in the drawings. To achieve a similar result to using the fluted tube, the openings in the ceramic manifold 53 may be grooved to provide the desired swirling of the combustion gas.
A large amount of tube assemblies 32 are utilized and positioned radially in layered rows about the combustion chamber as shown in the figures. They are short and small in diameter, are capable of high performance, and may be mechanically assembled by pre-manifolding a number of tube units thereby reducing assembly costs.
Each heater tube unit 12 is fitted radially inside openings 654 in a high pressure cylinder 56 positioned about the combustion chamber 24 and affixed thereto. In this regard, the end of tube 38 is flush with the outer surface 58 of cylinder 56 as shown most clearly at 60 in FIGS. 5 and 7.
Manifold 62 is then provided and is formed out of a thin sheet and punched to create raised openings 64 which are axially positioned with respect to openings 54. Openings 65 slide into engagement with the interior surfaces of the opening 50 in the heater tube units 32. Manifold 62 inlcudes raised interlocks 66 which allow the ready coupling of adjacent manifolds 68. The mainfold 62 are fitted around the cylinder 56 such that an annulus space 70 is defined therebetween which communicates with channels 42 on the heater tubes 32 and is coupled with the expansion space 28, as will be discussed. In addition, the channels 38 are restricted to communicating with the space outside the manifold 62 via the openings 64.
In this latter space, there is wrapped the regenerator matrix 20. It has been found that a regenerator fabricated out of a ceramic fiber such as Nextel 312 manufactured by the 3M Company, in a spiral wound mesh is very effective. Such heat resistant fibers are strong and flexible allowing for thin weaving and are low in conductivity. In the present invention, the use of such fibers is advantageous since with a conventional regenerator material, the short length in the temperature gradient direction would have an undesired amount of conduction loss which is here avoided. Such fibers provide high regenerator effectiveness and prevent loss of heat from hot to cold faces and have been found superior to the metallic wire designs heretofore utilized.
Positioned about the regenerator 20 is a radial gas flow cylindrical cooler 22 which comprises numerous hollow tapered tubes 72 assembled into a ring 74. Positioned between the tubes 72 are folded metal finstocks 76. The entire assembly of tubes 72 and finstocks 76 with perhaps end plates shown in phantom to keep them assembled, may then be brazed as a unit much like a conventional automobile radiator. Through the hollow of the tube 72 is passed the coolant (H 2 O) while through the channels formed by the finstocks 76 flow the working gas (air).
Note that rather than using finstocks, the tubes themselves may be provided with transversal grooves in the walls thereof; such grooves being in a zone between the ends to form the channels for air and then brazed together. By either method, many thousands of efficient passages are inexpensively made with few parts while having high thermal performance.
This entire heat exchange module 14 is then positioned in the engine 10. Located between the cooler 22 and the external casing 12 is the cold connecting channel which communicates with duct 29 and which may include channels 80 formed in a cold pressure cylinder or manifold 82 which may be part of the external casing 12.
With reference now to FIG. 6, a general description of the engine's operation is as follows. A combustor system 82 is provided for heating the heater tubes 32 and in turn the working fluid (air) passing through the tubes. Air for combustion enters at 84 and passes through a standard recuperative preheater 86 into the combustion chamber 24. From there, it moves axially along the heater tube units 32, through the ceramic manifold 53 (or fluted tube 52) and then to a return annulus 88, through the preheater 86 and out as exhaust at 90.
Movement of the working fluid (air) would be along the following paths. The expansion piston 28 is coupled to the hot connecting duct 30 and the ring duct 31 which is coupled to annulus space 70 between the manifold 62 and the cylinder 56. The channels 42 of the heater tubes are coupled with this area. The cold connecting duct 29 communicates with the channels formed by the finstocks 76, through the regenerator 20 and to the channels 38 formed in the heater tubes 32 via manifold 50.
Oscillating flow in the heater tubes between the channels as discussed earlier completes the cycle. Working fluid (air) from the expansion space is introduced axially into the annulus space 70, and flows up and down through the heater tube channels and out through the regenerator and cooler (both radial flow) then around the channels 80 and into the compression space.
Note that this cylindrical structure having radial flow allows for a very large flow area without high hoop and vessel stress that normally occur with the large diameter vessels associated with large flow areas for axial flow. In addition, the structure is largely self-insulating having attendant advantages.
Also, additional Stirling cycles may be added on the same crankshaft with their heat exchange module sharing the same combustor adding to the versatility and efficiency of such a system.
Thus, by the present invention, its objects and advantages are realized and although a preferred embodiment has been disclosed and described in detail herein, its scope should not be limited thereby, rather its scope should be determined by that of the appended claims. | A Stirling engine capable of utilizing air as a working fluid which includes a compact heat exchange module which includes heating tube units, regenerator and cooler positioned about the combustion chamber. This arrangement has the purpose and effect of allowing the construction of an efficient, high-speed, high power-density engine without the use of difficult to seal light gases as working fluids. | 5 |
BACKGROUND
With the increase in airfreight, and the utilization of a variety of narrow and wide-bodied aircraft, a need has arisen to couple cargo pallets together for handling of cargo which is larger than can be carried by a single cargo pallet and for ease of loading and securing pallets to the cargo floor.
When two pallets are connected together, the connection should be designed, as simply as possible to hold the pallets in a spaced relationship for ease of securing the pallets to the floor of the aircraft and also permit the pallets to travel over crests and valleys in the loading and unloading process without placing concentrated loads on the pallet attachments, pallet structure or aircraft floor.
U.S. Pat. No. 3,703,870 discloses a cargo pallet coupler. This coupler appears to join the pallets into a specified configuration; however, a special fitting must be attached to the pallets to receive the coupler-rod and the attachment is only preserved by a friction fit.
SUMMARY OF THE INVENTION
The inventive coupler provides a means for interconnecting two cargo pallets by the standard attach rings. A spacer with parallel sides contacts the side flanges on the pallet and limits the distance between the pallets. It is desirable that joined pallets have a uniform spacing so that they will contact loading brackets on the floor of cargo aircraft. The cargo attach rings of the pallets are captured by a positive connection with the coupler. Elastomeric bushings surrounding the bolts holding the attach rings to the coupler are compressed and contact the inside of the cargo attach rings and provide a flexible joint between joined pallets. The flanges on the attached pallets pivot against the parallel sides of the spacer member and the bendability of the joint is controlled by the compression applied to the elastomeric collars. The parallel sides of the spacer portion of the coupler provides a lateral stability between the attached pallets. The inventive coupler keeps the pallets in a spaced relationship and the coupled pallets can traverse crests and valleys in the loading and unloading process.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows two adjacent pallets interconnected by the inventive couplers;
FIG. 2 shows an enlarged top plan view of two pallets connected by the inventive coupler;
FIG. 3 shows a side elevation view along the line 3--3 of FIG. 2;
FIG. 4 shows a side elevation view along the line 4--4 of FIG. 2 wherein the attached bolt has been threaded into the coupler to a maximum depth; and
FIG. 5 shows an alternative construction of the inventive coupler.
DESCRIPTION OF PREFERRED EMBODIMENT
Referring to FIGS. 1 and 2, pallets 10 and 12 are held by the inventive couplers 14 and 15. The inventive coupler 14 is comprised of spacer member 16 and an offset base member 18 (FIGS. 2 and 3). The spacer member 16 holds pallets 10 and 12 at a prescribed distance apart by contacting flanges 20 and 22 of pallets 10 and 12, respectively.
Standard cargo attach rings 24 and 26 are located on the edge of pallets 10 and 12 and mounted for rotational movement on pins 27. In FIGS. 2 and 3 attach rings 24 and 26 have been rotated to the horizontal position to overlie base member 18. Plate 28 overlies attach rings 24 and 26. Bolts 30 and 32 penetrate plate member 28, attach rings 24 and 26, and thread into base member 18.
Surrounding bolts 30 and 32 are sheer collars 34 and 36. Rubber bushings 38 and 40 surround sheer collars 34 and 36. When bolts 30 and 32 are threaded into base member 18, as shown in FIG. 4, rubber bushings 38 and 40 are compressed between plate member 28 and base member 18. Sheer collars 34 and 36 act as a stop to limit the threading of bolts 30 and 32 into base member 18 by setting the minimum distance between plate member 28 and base member 18.
When bolts 30 and 32 have been threaded to the maximum distance into base member 18, rubber bushings 38 and 40 are expanded circumferentially and are in compressive engagement with inside of attach rings 24 and 26. When bolts 30 and 32 are threaded to the correct depth into base member 18 and cargo attach rings 24 and 26 have been captured between plate member 28 and base 18 and spacer member 16 is positioned vertically as shown in FIG. 3 between flanges 20 and 22. During the loading operation flanges 20 and 22 pivot on edges of spacer member 16 and provide for bendability of the two attached pallets. The sheer collars 34 and 36 also provide a larger bearing surface of the rubber bushings, thus reducing the tendency to cut the rubber bushings when a shearload is imposed.
The spacer 16 provides a lateral stability between the joined pallets 10 and 12 as the pallets move over the crests and valleys of the loading and cargo floors.
The rubber bushings 38 and 40 provide for a flexible attachment between the coupler and the pallet cargo attach rings. This flexible attachment permits the joined pallets to bend with respect to each other while traveling crests and valleys in loading and unloading operations. Bending of the joined pallets permits a larger area of the pallets to contact loading platform or aircraft floor during transfer thereby move evenly distributing the load of the pallets.
In operation, to connect two pallets 10 and 12 with the inventive coupler 14, the two pallets are moved into close proximity and spacer member 16 is placed between flanges 20 and 22. Attach rings 24 and 26 are then rotated into position overlying base member 18. Bolts 30 and 32 are inserted into plate member 28 and sheer collars 34 and 36 are placed on bolts 30 and 32. Rubber or elastomeric bushings 38 and 40 are placed encircling sheer collars 34 and 36 and the entire assembly is placed on rings 24 and 26. Bolts 30 and 32 are threaded into base member and tightened, linking plate member 28 to the base member 18. As rubber bushings 38 and 40 are compressed between the plate member 28 and base member 18, the bushings expand circumferentially and firmly contact the inside of attach rings 24 and 26. This rubber interface between the attach rings and the sheer collars provides a limited flexibility to the joint between the coupled pallets and allows a limited bendability between the joined pallets.
In the preferred embodiments of the inventive coupler 14 shown in FIG. 3, bolts 30 and 32 are tightened until metal sheer collars 36 and 38 contact base member 18 and plate member 28. This limits the compressibility of rubber bushings 38 and 40 and controls the bendability of the joint between the coupled pallets.
FIG. 5 depicts an alternate construction of the inventive coupler 41. Bolts 30 and 32 of FIG. 2 have been replaced by upstanding studs 42 and 44 which are attached to base member 46. Rubber bushings 48 and 50 encircle studs 42 and 44, respectively. To join pallets with this alternative embodiment of inventive coupler 41, the cargo attach rings are rotated and placed around the rubber bushings 48 and 50. When plate member 52 is placed over studs 42 and 44, nuts 54 and 56 are used to secure plate member 52 in place. As nuts 54 and 56 are tightened, plate 52 compresses rubber bushings 48 and 50 against base 46. The compressed rubber bushings 48 and 50 expand circumferentially to contact the cargo attach rings 24 and 26. When the enlarged collar portion of studs 42 and 44 contact plate 52, they provide a stop and limit the minimum distance between plate 52 and base 46. By limiting the compressibility of rubber bushings 48 and 50, their circumferential expansion and the contact with the inside of attach rings 24 and 26 is controlled as is the amount of flexibility of the joint between the coupled pallets.
While certain exemplary embodiments of this invention have been described above and shown in the accompanying drawings, it is to be understood that such embodiments are merely illustrative of, and not restrictive on, the broad invention and that we do not desire to be limited in our invention to the specific constructions or arrangements shown and described, since various other obvious modifications may occur to persons having ordinary skill in the art. | A coupler for use in joining cargo pallets by their attach rings. The coupler, normally used in pairs, provides for uniform spacing of joined pallets and bendability between pallets, permitting the joined pallets to traverse crests and valleys without putting concentrated loads on the coupler, the pallet, or cargo floor. | 1 |
BACKGROUND OF THE INVENTION
The present invention generally relates to high intensity discharge (“HID”) lamps, arc tubes, and methods of manufacture.
HID lamps such as metal halide and mercury lamps have found widespread use in lighting large outdoor and indoor areas such as athletic stadiums, gymnasiums, warehouses, parking facilities, and the like, because of the relatively high efficiency, compact size, and low maintenance of HID lamps when compared to other lamp types. Metal halide lamps are often preferred because of the efficiency of such lamps in producing white light.
HID lamps include an arc tube supported within an outer lamp envelope. The arc tube comprises a generally tubular body of light transmissive material such as quartz or ceramic material which forms a hermetically sealed light emitting chamber containing the lamp fill material and an inert fill gas. Generally, there are several types of arc tube bodies for HID lamps. One type of arc tube body is a “cylindrical” body formed from quartz tubing having the diameter of the generally cylindrical arc tube chamber in which the chamber is formed by pinch-sealing the end portions of the tubing. Another type of arc tube body is a “formed” body which is formed from quartz tubing of a much smaller diameter in which a bulbous light emitting chamber is formed by expansion under internal pressure between two end portions having the much smaller diameter of the tubing. The aforementioned types of arc tube bodies are used in forming “double-ended” arc tubes, i.e. arc tubes having spaced apart electrodes with one sealed at each end. The arc tubes for HID lamps may also be “single-ended” arc tubes having a bulbous chamber sealed at its only end.
An arc tube includes a pair of spaced apart electrodes between which the arc is established during operation of the lamp. In a double-ended arc tube, an electrode lead assembly is sealed in each end portion of the arc tube. The electrode lead assembly typically comprises a tungsten electrode, a molybdenum foil, and an outer molybdenum lead.
In the manufacture of double-ended arc tubes for HID lamps, either cylindrical body or formed body arc tubes, the light emitting chamber is sealed by positioning the electrode lead assemblies in each end portion of the arc tube body, heating a portion of each end portion, and then shrinking or pinching the heated portion around the electrode lead assembly positioned therein to thereby fix the position of the assembly relative to the arc tube body and to form a hermetic seal. The temperature of the heated portions typically reaches about 2000° C. or more. At these high temperatures, the metallic components of the electrode lead assembly positioned within the end portion are highly susceptible to corrosion when exposed to an uncontrolled atmosphere such as the air surrounding a factory production line, and any corrosion may significantly degrade the performance of the lamp and possibly lead to the mechanical failure of the lead assembly. Thus it is important to avoid exposure of the electrode lead assemblies to an uncontrolled atmosphere when the temperature of the assemblies is elevated during the manufacturing process.
In the context of the present invention, an “uncontrolled atmosphere” is any atmosphere other than one in which the composition of the atmosphere is strictly controlled such as the atmosphere in a glove box. The atmosphere surrounding a factory production line is considered to be an uncontrolled atmosphere even though there may be some control of the temperature, humidity, particulate content etc. of the atmosphere.
In the manufacture of HID lamps, the light emitting chamber of the arc tube body is dosed with solid lamp fill material such as one or more metal halides. This material is susceptible to moisture contamination when exposed to an uncontrolled atmosphere which significantly degrades the performance of the lamp. Thus in the manufacturing process, it is also important to avoid exposure of the solid lamp fill material to contaminating atmospheres.
In a known method of making arc tubes for HID lamps, an arc tube body is formed from vitreous material such as quartz. A fill/exhaust tube is then fused near the longitudinal center of the body where the light emitting chamber will be formed. The exhaust tube provides a means for communication between the interior of the chamber and the exterior of the arc tube body. The electrode lead assemblies are positioned and then pinch-sealed in the end portions of the arc tube body. During the pinch-sealing process, anon-reactive gas is introduced into the chamber through the fill/exhaust tube to prevent the exposure of the metallic components of the electrode lead assemblies to air when the components are heated during the sealing process, to thereby prevent corrosion of the metallic components. In the context of this invention, a “non-reactive” gas is a gas which is non-reactive with respect to the lamp components including, for example, the electrode lead assemblies and lamp fill material.
Once the ends of the arc tube body are sealed, the solid fill material and mercury are introduced into the chamber through the fill/exhaust tube. An inert fill gas is then introduced into the chamber at the desired fill pressure and the fill/exhaust tube is fused closed to thereby hermetically seal the chamber.
This prior art method suffers from several disadvantages including the substantial disadvantage that the chamber wall includes an irregularity at the point where the fill/exhaust tube was attached and then fused closed and tipped off. This irregularity may cause a cold spot on the wall of the chamber where halides will condense during operation of the lamp, and the condensation of halides may have a significant effect on the color uniformity of the light emitted from the lamp. The irregularity in the chamber may also disturb the light emitted from the chamber and the condensed halides may create shadows, making it difficult to control and direct the light. This is especially undesirable in optical systems such as fiber optics, projection display, and automotive headlamps. These disadvantages have a greater detrimental effect on lower wattage lamps which are smaller and where the irregularity includes a greater portion of the chamber wall.
A further disadvantage of the arc tube having a fused closed fill/exhaust tube applies to arc tubes mounted within a protective shroud or within tubular outer envelopes. The portion of the fill/exhaust tube which has been fused closed protrudes radially from the chamber wall of the arc tube. Thus a cylindrical shroud or tubular envelope must be of a larger diameter to envelope an arc tube with a radially protruding tip.
The prior art has developed methods of making “tip-less” arc tubes to obviate the deficiencies of the arc tube having a fused closed fill/exhaust tube. However, the prior art methods of making tipless arc tubes require the use of a controlled environment during at least some of the process steps.
Generally, the known methods of making tipless arc tubes include the steps of providing an arc tube body; positioning and then sealing an electrode lead assembly in one end portion of the arc tube body; introducing the solid lamp fill material and an inert fill gas into the interior of the body through the remaining open end portion of the body; and positioning and then sealing another electrode lead assembly in the remaining open end portion of the body to thereby form a hermetically sealed light emitting chamber.
To prevent oxidation of the metallic components of the first electrode lead assembly during the sealing process of the first end portion, it is known to introduce a non-reactive gas into the interior of the body through the other end portion to thus create a flow of non-reactive gas past the lead assembly during the sealing process. This prevents exposure of the metallic components to a reactive atmosphere such as moisture laden air during the sealing process. The non-reactive gas is commonly introduced into the interior of the body by conventional means such as fitting a hose over the end of the open end portion or inserting a probe into the interior of the body through the open end portion.
The interior of the body is then filled with a non-reactive gas through the open end portion prior to the introduction of the solid lamp fill material. The lamp fill material is typically stored in a dry non-reactive atmosphere and thus may be introduced into the interior of the body without contamination.
To prevent oxidation of the metallic components of the second electrode lead assembly during the sealing process of the second end portion, the prior art teaches that the interior of the arc tube body must be isolated from an uncontrolled atmosphere once the solid fill material and mercury are introduced into the interior of the arc tube body and the second electrode lead assembly is positioned in the remaining open end portion.
The prior art teaches that the interior of the arc tube may be isolated from an uncontrolled atmosphere by either (i) placing the arc tube body in a controlled atmosphere such as a glove box as taught in U.S. Pat. No. 5,108,333 to Heider et al. dated Apr. 28, 1992 or (ii) connecting the open end to a vacuum system which provides the necessary seal as taught in U.S. Pat. No. 5,505,648 to Nagasawa et al. dated Apr. 9, 1996. As illustrated by the prior art, one end portion of the arc tube body must be long enough to enclose the entire electrode lead assembly when the assembly is positioned within the end portion. Once the arc tube is isolated, the arc tube body is filled with the inert fill gas at the desired pressure and then the end portion is fused closed to the outside of the electrode lead assembly to enclose the entire assembly within the body. The arc tube may then be removed from the glove box or vacuum system and the second end portion is sealed by shrinking or pinching, after which the excess portion of the end portion may be removed to expose the outer lead of the electrode lead assembly.
The prior art methods suffer from the significant disadvantage of the requirement for isolating the arc tube body from the uncontrolled atmosphere. This has generally required the use of a glove box or vacuum system. Such methods are complex and difficult to automate.
Accordingly, it is an object of the present invention to obviate many of the deficiencies of the prior art and provide a novel HID lamp, arc tube and method of making arc tubes.
It is another object of the present invention to provide a novel arc tube and method of making arc tubes for HID lamps which obviates the need to perform any process steps within a controlled atmosphere.
It is a further object of the present invention to provide a novel arc tube and method of making tipless arc tubes for HID lamps in which the arc tube remains open to an uncontrolled atmosphere during the step of finally sealing the arc tube.
It is yet another object of the present invention to provide a novel arc tube and method of making tipless arc tubes for HID lamps in which communication of an inert fill gas with an uncontrolled atmosphere such as air is maintained until the arc tube is hermetically sealed.
It is yet a further object of the present invention to provide a novel arc tube and method of making arc tubes for HID lamps which obviates the need to remove a portion of the end portion to expose the outer portion of the electrode lead assembly.
It is still another object of the present invention to provide a novel arc tube and method of making arc tubes for HID lamps in which each end portion of the arc tube body has substantially the same length as the end portions of the finished arc tube.
It is still a further object of the present invention to provide a novel apparatus for extending the tubular opening formed by the end portion of an arc tube body and method of making arc tubes for HID lamps.
It is often desirable to obtain a final fill gas pressure which is significantly below atmospheric pressure at substantially room temperature, i.e., pressures below 500 torr. Final fill gas pressures below about one-half atmosphere are common and may be as low as about 30 torr. A fill pressure of about 100 torr is common in metal halide lamps. In order to obtain such final subatmospheric fill pressures, the prior art uses mechanical means to evacuate the interior of the arc tube to the desired pressure prior to hermetically sealing the interior of the arc tube, i.e., by fusing closed the fill/exhaust tube or shrinking or pinching the remaining open end portion in a tipless arc tube. Such methods require the use of expensive pumps and/or vacuum systems, are complex, and difficult to automate.
The patent to Heider et al. discloses that a “slight” under-pressure of the fill gas may be obtained by heating the fill gas and fusing closed the open end portion within a glove box and then removing the arc tube from the glove box to shrink or pinch seal the remaining unpinched end portion. Heider et al. disclose raising the temperature of the fill gas by only 100° C. prior to fusing closed the arc tube to obtain a slight under-pressure when the fill gas cools. If the fill gas is heated at atmospheric pressure, a temperature differential of 100° C. will provide a final fill gas pressure of greater than 500 torr when the arc tube is sealed and cooled. There is no disclosure in Heider et al. that a significantly subatmospheric fill pressure, i.e., a pressure less than 500 torr, may be obtained by this process, or that the fill gas temperature may be controlled outside of a glove box while open to an uncontrolled atmosphere.
Accordingly, it is yet another object of the present invention to provide a novel arc tube and method of making arc tubes for HID lamps which obviates the need to mechanically evacuate the arc tube to obtain a significantly subatmospheric fill pressure.
It is still another object of the present invention to provide a novel arc tube and method of making arc tubes for HID lamps in which the temperature of the fill gas is controlled prior to sealing the arc tube in an uncontrolled atmosphere.
It is yet another object of the present invention to provide a novel arc tube and method of making arc tubes for HID lamps having significantly subatmospheric fill pressure in which there is no pressure differential at the time of sealing.
These and many other objects and advantages of the present invention will be readily apparent to one skilled in the art to which the invention pertains from a perusal of the claims, the appended drawings, and the following detailed description of the preferred embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross-sectional view of an arc tube body having a bulbous light emitting chamber.
FIGS. 2 a-e illustrate the prior art process steps for forming the arc tube body illustrated in FIG. 1 .
FIG. 3 a illustrates the step of heating the end portion of an arc tube body while flushing the interior of the body with an inert gas during the pinch sealing process.
FIG. 3 b is a cross-sectional view of an arc tube body having an electrode lead assembly pinch sealed in one end.
FIG. 4 is a schematic illustrating an electrode lead assembly.
FIG. 5 illustrates the step of introducing the solid lamp fill material and mercury into the interior of the chamber.
FIG. 6 is a cross-sectional view of a prior art arc tube body having its elongated end portion tipped off beyond the electrode lead assembly.
FIG. 7 illustrates the step of heating the upper end portion of an arc tube body while maintaining the interior of the body open to the surrounding atmosphere.
FIG. 8 is a cross-sectional view of an arc tube made by one method of the present invention.
FIG. 9 is a cross-sectional view of one embodiment of an arc tube body according to the present invention.
FIG. 10 is a cross-sectional view of an arc tube made from the arc tube body illustrated in FIG. 9 .
FIG. 11 a illustrates the step of flushing and filling the arc tube body with the final fill gas according to the present invention.
FIG. 11 b illustrates the step of positioning the electrode lead assembly and pinch sealing the second end portion of the arc tube according to the present invention.
DESCRIPTION OF PREFERRED EMBODIMENTS
The present invention finds utility in arc tubes for all types and sizes of HID lamps and methods of manufacture of such lamps generally. By way of example only, certain aspects of the present invention will be described in connection with tipless quartz formed body arc tubes for double-ended metal halide lamps.
FIG. 1 illustrates a prior art arc tube body which has been formed from a quartz tube. The arc tube body 10 comprises a bulbous light emitting chamber 12 intermediate open tubular end portions 14 , 16 . The arc tube body 10 may be formed using any suitable conventional method.
Formed body arc tubes may be manufactured in the manner described in the Lamouri et al. copending patent application Ser. No. 09/597,547 filed Jun. 19, 2000, and entitled “Horizontal Burning HID Lamps And Arc Tubes” assigned to the assignee of the present invention. FIGS. 2 a-e illustrate such a method of forming arc tubes from quartz tubing (FIG. 2 a ) by loading the tubing on a lathe and heating the tubing (FIG. 2 b ), gathering the heated tube by axial movement of the tube (FIG. 2 c ), and expanding with internal pressure the gathered tube against a mold (FIG. 2 d ) to obtain the desired shape of the arc tube body (FIG. 2 e ). The thickness of the arc tube body may be adjusted by the amount of quartz accumulated in the gathering process and the shape of the arc tube body is determined by the shape of the mold.
As shown in FIGS. 3 a and 3 b , a first electrode lead assembly 18 is positioned within the open tubular end portion 14 and the end portion 14 is sealed using a conventional pinch sealing process. During the pinch sealing process, a portion of the end portion 14 is heated to soften the quartz, and then the softened portion is pressed together and around the portion of the electrode lead assembly 18 positioned therein using conventional pinch jaws (not shown) forming pinch seal 20 . The pinch seal 20 fixes the position of the assembly 18 relative to the arc tube body 10 and provides a hermetic seal between the interior of the chamber 12 and the exterior of the body 10 through the end portion 14 .
The electrode lead assembly 18 may be a conventional lead assembly comprising several metallic components including a tungsten electrode 22 , a molybdenum foil 24 , and a molybdenum outer lead 26 as shown in FIG. 4 . During the pinch sealing process, the metallic components may reach temperatures as high as 2000° C. or more when the quartz is softened. At such high temperatures, the metallic components are highly susceptible to corrosion if exposed to moisture in a reactive atmosphere such as air. To prevent such corrosion, an inert gas is introduced into the chamber 12 through the remaining open tubular end portion 16 and flows past the lead assembly 18 during the pinch sealing process. The gas may be introduced by any conventional means such as insertion of a probe 28 as shown in FIG. 3 a or the connection of a hose (not shown) to the open end portion 16 . The gas may be any inert gas such as nitrogen or argon or mixtures thereof.
The next step is to dose the arc tube body with the desired fill material by introducing the material into the chamber 12 through the remaining open end portion 16 . The solid lamp fill material 30 may be introduced into the chamber 12 through the remaining open end portion 16 by any conventional means such as a pin type dispenser of lamp fill pellets manufactured by APL Engineered Materials, Inc. Mercury 31 , if desired, may also be introduced into the chamber 12 through the end portion 16 by any conventional means. FIG. 5 illustrates an arc tube body 10 having lamp fill pellets 30 and mercury 31 within the chamber 12 .
The remaining steps in the process include the flushing and filling of the chamber with the final fill gas, the positioning of the second electrode lead assembly in the remaining open end portion, and the sealing of the remaining open end portion. As discussed with respect to the pinch sealing of the first end portion, it is important to prevent the exposure of the metallic components of the electrode lead assembly to a corrosive atmosphere at high temperature.
The prior art methods teach the necessity to isolate the components from an uncontrolled atmosphere by either (i) placing the arc tube body in a glove box, or (ii) connecting the open end of the arc tube body to a vacuum system prior to filling the interior of the arc tube body with the final fill gas and positioning the second electrode lead assembly. As shown in FIG. 6, the open end portion 16 may be fused closed outside the lead assembly 32 once the final fill pressure is obtained to isolate the interior of the chamber 12 containing an inert atmosphere. Thus the prior art prevents corrosion of the metallic components of the lead assembly during the pinch sealing of the end portion 16 by isolating the components in an inert atmosphere within the interior of the arc tube body.
It has been discovered that the isolation of the interior of the arc tube from an uncontrolled atmosphere by use of a glove box or vacuum system may be obviated by orienting the arc tube body 10 so that the open end portion 16 extends upwardly as shown in FIGS. 5 and 7, and relying on the relative weight of the fill gas to air to maintain a fill of inert gas within the arc tube body. The final inert fill gas may be introduced into the interior of the chamber 12 by insertion of a suitable conventional probe 34 . The fill gas may be any inert gas such as argon, neon, xenon, krypton, or a combination thereof. In the preferred embodiment of the invention, the fill gas comprises a mixture of argon and krypton. The mixture of argon and krypton is heavier than air and will tend to remain within the interior of the arc tube body 10 so long as the body remains in a substantially vertical orientation, thus retarding the influx of the lighter contaminated air of the uncontrolled atmosphere surrounding the arc tube.
The interior of the arc tube body 10 is flushed and filled with the fill gas to the tip 38 of the end portion 16 so that all other gases are displaced. Once the arc tube body is flushed and filled, the probe 34 may be removed and the second electrode lead assembly 32 is positioned within the end portion 16 as shown in FIG. 7 . The end portion 16 must extend sufficiently above the lead assembly 32 so that the lead assembly 32 will remain immersed in the column of fill gas within the end portion 16 despite some mixing of the fill gas with the uncontrolled atmosphere surrounding the arc tube body near the tip 38 of the end portion 16 .
As shown in FIGS. 7 and 8, the second end portion 16 may then be sealed by a conventional pinch sealing process. A portion of the end portion 16 is heated to soften the quartz, and then the softened portion is pressed together and around the portion of the electrode lead assembly 32 positioned therein using conventional pinch jaws (not shown) forming pinch seal 36 . The pinch seal 36 fixes the position of the assembly 32 relative to the arc tube body 10 and provides a hermetic seal between the interior of the chamber 12 and the exterior of the body 10 through the end portion 16 . In another embodiment, the end portion may be sealed by a shrink sealing process.
As further illustrated in FIG. 8, the chamber 12 is now hermetically sealed from the exterior of the arc tube body 10 . The excess portion of the end portion 16 may then be removed to expose the outer lead 42 of the electrode lead assembly 32 .
FIGS. 9 and 10 illustrate another emdodiment of the present invention. The arc tube body 50 may be formed having a chamber 52 intermediate the open end portions 54 , 56 . The end portions 54 , 56 may have substantially the same length. In the preferred embodiment, the length of the end portions 54 , 56 of the arc tube body 50 may be substantially the length of the end portions of the finished arc tube so that the step of trimming the excess portion of the second end portion once the chamber is sealed may be eliminated. However, it remains necessary to provide a column of fill gas which is sufficiently long so that the second electrode lead assembly 58 positioned within the second end portion 56 is completely immersed in fill gas during the pinch sealing process of the second end portion.
In one embodiment of the present invention, the column of fill gas may be extended beyond the length of the end portion by communication of the open end portion with a mechanical means forming an elongated shaft having substantially the same diameter as the outside diameter of the end portion. In the embodiment shown in FIGS. 11 a and 11 b , a flush and fill block 60 forms a main shaft 62 which communicates with the open end portion 56 of the arc tube body 50 during the steps of positioning the electrode lead assembly 58 , flushing/filling the body 50 with the final fill gas, and pinch sealing the end portion 56 .
The block 60 forms the main shaft 62 and one or more auxiliary shafts 64 which provide communication between the main shaft 62 and the surrounding atmosphere. The open end of the end portion 56 may be positioned relative to the block 60 to effect communication of the main shaft 62 with the tubular opening formed by the end portion 56 . The interior of the arc tube chamber 52 and open end portion 56 may be flushed and filled with the final fill gas by insertion of a conventional probe 66 into the chamber 52 as shown in FIG. 11 a.
Once the arc tube body 50 is flushed and filled with the final fill gas, the probe 66 may be removed. The fill gas now fills the end portion 56 and the main shaft 62 and tends to remain within the shaft 62 as a result of the relative weight of the fill gas to the surrounding atmosphere. The electrode lead assembly 58 may then be positioned within the end portion 56 and main shaft 62 using a conventional assembly holder 68 as shown in FIG. 11 b . With the fill gas filling the shaft 62 to the top, the electrode lead assembly 58 may be completely immersed in the fill gas to prevent corrosion during the pinch sealing process. Once the electrode lead assembly 58 is positioned, the end portion 56 may be pinch sealed using a conventional pinch seal process. In another embodiment, the end portion 56 may be sealed by a shrink seal process.
In many applications, it is desirable to provide an arc tube having a fill gas pressure which is significantly below atmospheric pressure at substantially room temperature, e.g., pressures lower than 500 torr. Arc tubes having fill gas pressure below one-half atmosphere and even as low as 30 torr are common. In order to obtain such subatmospheric fill gas pressures, the prior art methods use mechanical systems such as vacuum pumps to control the fill gas pressure prior to fusing closed the end portion and then pinch or shrink sealing the end portion to finally seal the chamber. Such mechanical systems are expensive and the process steps using such systems are difficult to automate.
In one aspect of the present invention, the use of such mechanical systems is obviated in providing significantly subatmospheric fill gas pressures in arc tubes. During the final pinch sealing process to hermetically seal the upper end portion 16 , 56 , communication between the interior of the chamber 12 , 52 and the uncontrolled atmosphere surrounding the arc tube body 10 , 50 is maintained. Thus the pressures of the fill gas and surrounding atmosphere are the same and the fill gas may expand or contract responsive to the temperature of the fill gas relative to the temperature of the surrounding atmosphere. In order to obtain a significantly subatmospheric fill gas pressure at substantially room temperature, the arc chamber may be heated to thereby elevate the temperature of the fill gas during the pinch sealing process to thereby reduce the density of the fill gas within the chamber at the time the chamber is hermetically sealed. The pressure of the fill gas at the time the chamber is sealed will be equal to the pressure of the surrounding atmosphere because communication between the atmospheres is maintained during the sealing process. In the uncontrolled atmosphere of a factory production area, the pressure will be substantially atmospheric pressure and elevating the temperature of the fill gas will result in flow of fill gas from the arc tube through the open end portion to prevent contamination from the mixing of the gases at the end of the tube. When the arc tube and fill gas cools to room temperature, the pressure of the fill gas in the fixed volume of the chamber will be reduced and the final pressure of the fill gas at substantially room temperature may be controlled by controlling the temperature of the fill gas at the time the chamber is sealed.
In a preferred embodiment, a burner 70 applies direct heat to the bulbous chamber 52 of the arc tube body 50 during the pinch sealing process to control the temperature of the fill gas within the chamber 52 . The intensity of the burner 70 , and thus the amount of heat applied to the fill gas, may be controlled according to the desired fill gas pressure of the completed arc tube.
Alternatively, in another aspect of the invention, the fill gas may be cooled at the time the chamber is hermetically sealed to obtain a superatmospheric fill gas pressure at substantially room temperature. Care must be given to prevent contamination, e.g., by continuing to introduce fill gas into the arc tube during the cooling process.
While preferred embodiments of the present invention have been described, it is to be understood that the embodiments described are illustrative only and the scope of the invention is to be defined solely by the appended claims when accorded a full range of equivalence, many variations and modifications naturally occurring to those of skill in the art from a perusal hereof. | A tipless arc tube for a high intensity discharge lamp and method of manufacture wherein the arc tube may remain open to an uncontrolled atmosphere during the step of hermetically scaling the arc tube. The novel arc tube and method obviate the need to perform any process steps within a controlled atmosphere. The pressure of the fill gas sealed within the arc tube may be controlled by controlling the temperature of the fill gas during the step of hermetically sealing the arc tube. The novel arc tube and method obviate the need to use a pump to control the fill gas pressure. | 7 |
BACKGROUND OF THE INVENTION
In typical ball or roller bearings the rotating elements slide against each other or slide against a cage. This sliding friction causes heat and wear, and necessitates providing clearances and lubrication in the bearing. In U.S. Pat. No. 1,289,062 issued to A. L. Westman a rolling contact bearing is illustrated, but it is excessively complex in that the rollers are complicated and make more contacts than necessary.
SUMMARY OF THE INVENTION
The invention provides axial and radial load rolling contact bearing devices including two bearing races, major rotating elements which are located between these races and carry the loads, minor rotating elements which prevent contact between the major rotating elements, and retainers for positioning the minor rotating elements. There is only rolling contact between all elements.
In some embodiments the minor rotating elements are located to one side of the major rotating elements with respect to the races, in others they are located on both sides, and in yet others the minor rotating elements pass between the major rotating elements and are supported on both sides. The contact between elements may be rolling point contact as a ball rolling on a flat surface, or rolling line contact as a cylinder rolling on a flat surface. Rolling contact is obtained by locating the minor rotating elements on the side of the major rotating elements generally opposite the side to which their retaining race is attached, and further by properly dimensioning the elements. In some embodiments it is possible to provide speed change devices by using dimensions that will provide to one of the retaining races a speed differential with respect to the race to which it would otherwise be attached, and by then permitting this retaining race to rotate independently. In other embodiments the minor rotating elements may carry part of the load.
Accordingly, it is an object of the present invention to provide an improved rolling contact bearing without sliding friction. Another object of the invention is to provide a rolling contact bearing in which there are zero clearances between elements, thus providing for exact centering of rotating shafts with no displacement due to clearances.
A further object of the invention is to provide a rolling contact device wherein speed ratios between rotating elements ranging from infinitely small to infinitely large can be obtained without sliding friction and without clearances between the elements of the device.
A still further object of the invention is to provide rolling contact devices wherein the rotating elements are simple spheres and cylinders, to thus minimize the manufacturing cost.
Yet another object of the invention is to provide rolling contact bearing devices wherein loads are distributed between major and minor rotating elements.
Other objects of this invention will appear from the following description and appended claims, reference being had to the accompanying drawings forming a part of this specification wherein like reference characters designate corresponding parts in the several views.
FIG. 1 is a vertical sectional view of a radial load rolling contact bearing wherein loads are transferred through spherical ends of rollers and balls are used to provide separation between these rollers in accordance with one embodiment of the invention.
FIG. 2 is a sectional view taken along line 2--2 of FIG. 1 and looking in the direction of the arrows.
FIG. 3 is a vertical sectional view of a device similar to FIG. 1 in which axial bearing loads are accommodated instead of radial loads.
FIG. 4 is a vertical sectional view of the right portion of a device similar to FIG. 1 in which both radial and axial bearing loads are accommodated instead of only radial loads.
FIG. 5 is a vertical sectional view of the central and right portions of a device similar to FIG. 3, but in which speed changes are obtained in accordance with another embodiment of the invention.
FIG. 6 is a vertical sectional view of the central and right portions of a device similar to FIG. 5 in which speed changes are obtained.
FIG. 7 is a vertical sectional view of the upper portion of a radial load rolling contact bearing similar to FIG. 1 in which loads are transferred through rollers instead of balls.
FIG. 8 is a vertical sectional view of the left portion of a device similar to FIG. 7 in which axial bearing loads are accommodated instead of radial loads.
FIG. 9 is a vertical sectional view of the left portion of a device similar to FIG. 8 in which radially outward movement of the load bearing rollers is prevented by a rotating retaining ring instead of by a stationary retaining ring.
FIG. 10 is a vertical sectional view of the upper portion of a radial load rolling contact device similar to FIG. 7 in which the separating balls contact axial extensions of the load bearing rollers instead of a groove in the load bearing rollers in accordance with another embodiment of the invention.
FIG. 11 is a vertical sectional view of the upper portion of a device similar to FIG. 10 in which the separating elements are rollers instead of balls.
FIG. 12 is a vertical sectional view of the upper portion of a device similar to FIG. 10 in which the separating balls are located radially outwards of the load bearing rollers instead of radially inwards and in which the separating balls roll in grooves in the load bearing rollers.
FIG. 13 is a vertical sectional view of the upper portion of a radial load rolling contact device in which both major and minor rotating elements are balls in accordance with another embodiment of the invention.
FIG. 14 is a vertical sectional view of the left portion of a device similar to FIG. 13 in which axial bearing loads are accommodated instead of radial loads.
FIG. 15 is a vertical sectional view of the left portion of a device similar to FIG. 13 accommodating both radial and axial bearing loads.
FIG. 16 is a vertical sectional view of the upper portion of a device similar to FIG. 13 in which the load bearing elements are rollers instead of balls.
FIG. 17 is a vertical sectional view of the left portion of a device similar to FIG. 16 in which axial bearing loads are accommodated instead of radial loads.
FIG. 18 is a vertical sectional view of the upper portion of a device similar to FIG. 16 in which both radial and axial bearing loads are accommodated.
FIG. 19 is a vertical sectional view of a radial load rolling contact bearing in which the minor rotating elements are rollers supported on both sides of the major rotating elements in accordance with another embodiment of the invention.
FIG. 20 is a sectional view taken along the line 20--20 of FIG. 19 and looking in the direction of the arrows.
FIG. 21 is a vertical sectional view of the left portion of a device similar to FIG. 19 in which axial bearing loads are accommodated instead of radial loads.
FIG. 22 is a vertical sectional view of the upper portion of a device similar to FIG. 20 in which the load bearing elements are rollers instead of balls and in which the minor rotating elements are located radially outwards of the load bearing elements instead of radially inwards.
FIG. 23 is a vertical sectional view of the left portion of a device similar to FIG. 22 in which both axial and radial loads are accommodated instead of only radial loads.
FIG. 24 is a vertical sectional view of the upper portion of a radial load rolling contact device in which both the load bearing rotating elements and the secondary rotating elements are balls and in which the secondary balls are located on both sides of the load bearing balls in accordance with another embodiment of the invention.
FIG. 25 is a vertical sectional view of the left portion of a device similar to FIG. 24 in which both radial and axial loads are accommodated instead of only radial loads.
FIG. 26 is a vertical sectional view of the left portion of a device similar to FIG. 24 in which the load bearing elements are rollers instead of balls and in which axial loads are accommodated instead of radial loads.
Before explaining the present invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practiced or carried out in various ways. Also, it is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.
DETAILED DESCRIPTION
Turning now to FIGS. 1 and 2 there is shown device 10 which is a radial load rolling contact bearing, there being no sliding contact present. Radial loads are transferred from a circular surface on outer race 11 through the spherical ends of rollers 12, which comprise the major rotating elements, to a circular surface on inner race 13. Balls 14 are the minor rotating elements and are alternately interposed between rollers 12, rolling against the constricted portion of their sides to prevent their touching each other. Balls 14 also roll in a groove in circular retaining race 15 and are held in position thereby. The blunt ends 12a of rollers 12 have the same diameter as their spherical ends, and roll on a circular surface on the inner periphery of retaining race 15, which has the same diameter as the inner periphery of outer race 11. Retaining race 15 is adjustably screwed onto outer race 11, but could be otherwise fastened thereto. Please note that the elements of this radial load device are oriented generally perpendicular to its axis. Note too that balls 14 and race 15 carry none of the load because races 11 and 13 are on opposite sides of the spherical ends of rollers 12.
All elements of device 10 will be in rolling contact provided there is no mechanical interference and provided the following dimensional proportions are observed: ##EQU1## where D 1 is the diameter of the inner periphery of race 11 where it contacts rollers 12, D 2 is the diameter of the groove in retaining race 15 where it contacts balls 14, d 1 is the major diameter of rollers 12, and d 2 is the diameter of the constricted midsection of rollers 12 where they contact balls 14.
Device 30 of FIG. 3 is similar to device 10, but is instead an axial load rolling contact bearing. Loads are transferred axially from upper race 31 through the large ends of rollers 32 to lower race 33. The smaller ends of rollers 32 roll on a radially inward surface of race 33. Balls 34 are interposed between rollers 32, contacting them on their concave central portion and being held in position by retaining race 35. Race 35 is adjustable and may be used to provide positive clearance, zero clearance, or pressure between the elements, depending on how far race 35 is screwed onto race 33. All elements will be in rolling contact if their diameters of rolling contact are proportional to their distance from the device 30 axis and if the axes of rollers 32 are perpendicular to this axis.
FIG. 4 depicts device 40 which is a combination of devices 10 and 30 in that it will accommodate both axial and radial loads. The large ends of rollers 42 are in rolling contact with races 41 and 43 and transfer loads therebetween. The small ends of rollers 42 roll on a radially inward surface of race 43. Adjustable retaining race 45 screws onto race 43 and holds balls 44 in position between rollers 42. Only one roller 42 and one ball are shown in FIG. 4, but there would be many more of each.
In FIG. 5 is shown device 50 which is a rolling contact speed-change device. It is similar to device 30, except that the narrow central portion of each roller has a diameter less than that optimum which would cause the retaining race to remain stationary with respect to the lower race. In device 50 axial loads are transferred from rotating upper race 51 through the large ends of rollers 52 to stationary lower race 53. The small ends of rollers 52 roll on a radially inward surface of lower race 53. Balls 54 are interposed between the narrow portions of rollers 52 and are held in position by retaining race 55. However, the central portion of rollers 52 is only about half the optimum diameter; thus race 55 will rotate at about half the speed of upper race 51, and in the same direction. Ball 56 is positioned along the rotating axis of device 50 in recesses in the center of races 51 and 55 and may be used to transfer a portion of the axial load through the bending of the disc portion of race 55 to balls 54 and from thence to rollers 52 and thereafter to lower race 53.
In device 50 it can be seen that when race 51 is the driving element, the speed of race 55 will decrease as the diameter of the central portion of rollers 52 increases until the optimum diameter is reached, at which diameter the speed of race 55 will be zero with respect to lower race 53. However, if race 55 is the driving element, the speed of race 51 will increase as the diameter of the central portion of rollers 52 increases until the optimum is reached, at which diameter the speed of race 51 will theoretically be infinite; actually slippage instead of rotation will occur at diameters near the optimum.
If the shaft is removed from race 55 or is not utilized, device 50 becomes an axial load bearing with race 55 simply being a freely rotating retainer. The size of the central portion of rollers 52 in this event will not matter, provided each is the same diameter.
Device 60 of FIG. 6 is another rolling contact speed change device, and is essentially what would be obtained by inverting device 50 and holding race 51 stationary. Device 60 differs further in that it provides concentric shafts at the same end of the bearing. Loads are transferred from race 61 through the large ends of rollers 62 to lower race 63. Balls 64 are interposed between rollers 62 and held in position by retaining race 65 which is free to rotate and is held in position by ball 66 at the axis of the bearing. Note that the diameter of the central portion of roller 62 is larger than the optimum and thus races 61 and 65 will rotate in opposite directions; whereas in device 50 with a central diameter less than the optimum, races 51 and 55 have the same direction of rotation. When race 61 is the driving element and lower race 63 is stationary, speed differentials down to zero may be obtained between races 61 and 65; extremely high speed differentials being theoretically possible when race 65 is the driving element.
FIGS. 7, 8, and 9 depict devices which are similar to those of FIGS. 1, 2, 3, and 4, except the load bearing elements are rollers instead of balls and thus the load bearing contacts are lines instead of points.
In FIG. 7, device 70 is a radial load rolling contact bearing in which loads are transferred from outer race 71 through rollers 72 to inner race 73. Balls 74 roll between rollers 73 in concave grooves at one of their ends and are held in position by rolling also in an adjustable V-groove which is formed between a radially inward extension of outer race 71 and retaining race 75; adjustment being provided by the extent to which the two are screwed together. Snap ring 76 prevents axial movement between rollers 72 and inner race 73.
Rolling contact bearing 80 of FIG. 8 is similar to bearing 70 except that it is an axial load bearing. Upper race 81 transfers loads through rollers 82 to lower race 83 by rolling line contact. Rollers 82 have a rounded portion at one end which is in rolling point contact with a reverse slope portion of lower race 83 which prevents them from shifting radially outwards. Balls 84 are interposed between rollers 82 to preclude their mutual contact. Retaining race 85 is screwed onto lower race 83 and has a concave portion which is in rolling contact with balls 84 and holds them in position. Race 85 may be made of thin, flexible material so as to exert a readily adjustable amount of pressure on rollers 82.
Combination radial and axial load bearings similar to devices 70 or 80 may be obtained by tilting the rollers to a position intermediate to them and by using a retainer similar to either device.
FIG. 9 shows device 90 which is an axial load bearing similar to device 80 but using a moving ring to prevent radially outward movement of the rollers. In device 90, upper race 91 is in rolling line contact with rollers 92, which are also in rolling line contact with lower race 93. Separating balls 94 are held in position by retaining race 95 which is shown fastened to lower race 93. The rounded, radially outward ends of rollers 92 are in point contact with concave retainer ring 96 which is free to rotate and prevents rollers 92 from moving radially outwards.
FIGS. 10, 11 and 12 depict devices 100, 110, and 120 which are similar to device 70, except that the minor rotating elements contact axial extensions of the major rotating elements instead of a portion between their ends.
In FIG. 10, device 100 has an outer race 101 which transfers radial loads to inner race 103 by means of rolling line contact with rollers 102. Balls 104 are interposed between axial extensions 102a at one end of rollers 102, and are held in position therebetween by concave retaining race 101a, which is an extension of race 101. Snap ring 105 prevents axial shifting of the rollers 102 with respect to outer race 101. Both axial and combination radial-axial load variations of device 100 are also possible.
A major variation of device 100 would be to increase the diameter of axial extensions 102a so that they have a greater diameter than the load bearing portion of rollers 102 and then interposing balls 104 radially outwards between extensions 102a instead of radially inwards. The retaining race would then be attached to inner race 103 instead of to outer race 101, as in the device of FIG. 12, which will be discussed later.
FIG. 11 represents device 110 which is similar to FIG. 10, except that the interposed elements are rollers instead of balls. Outer race 111 transfers radial loads through rollers 112 to inner race 113. Interposed rollers 114 are held in position by retaining race 111a, which is integral with race 111. Snap ring 115 holds rollers 112 in position.
FIG. 12 shows device 120 which is similar to device 100 and to the major variation there described. In device 120 the interposed balls are located radially outwards instead of radially inwards of the centerlines of the load bearing rollers, and the retaining race is fastened to the inner instead of the outer race. Device 120 has an outer race 121 in rolling line contact with rollers 122, which in turn roll against inner race 123. Balls 124 are interposed between the V-notched ends 122a of rollers 122 and are held in position by retaining race 125, which is screwed onto inner race 123. Note that the inner periphery of retaining race 125 is tapered where it contacts balls 124 and thus provides a means of adjusting the bearing. Note also that each ball 124 has two points of contact with adjacent rollers 122.
FIGS. 13, 14, and 15 depict rolling point contact devices wherein both the load bearing rotating elements and the secondary rotating elements are balls. In FIG. 13, device 130 is a radial load rolling contact bearing in which outer race 131 transfers loads through balls 132 to inner race 133. Balls 134 are interposed between balls 132 and are held in position by retaining race 131a which is attached to or integral with outer race 131.
All elements will be in rolling contact and balls 132 will not twist as they rotate if the following dimensional proportions are observed: ##EQU2## where D 1 is the diameter of the inner periphery of race 131, D 2 is the diameter of the circle of contact of race 131a where it contacts balls 134, d 1 is the diameter of balls 132, and d 2 is the diameter of the circular loci on balls 132 where they contact balls 134. For some applications a minor deviation from this proportion may be desireable in that such deviation will cause balls 132 to twist as they rotate, thus theoretically assuring that every portion of the surface of balls 132 will at one time or another bear the load and that wear will thus be evenly distributed over their surface.
In a variation of device 130, race 133 would be shifted slightly clockwise so that it contacts balls 132 at a greater distance from retaining race 131a. This will give the bearing an axial load bearing capability and will cause balls 134 and race 131a to carry such axial load.
FIG. 14 depicts device 140 which is an axial load variation of device 130. Loads are transferred from upper race 141 through balls 142 to lower race 143. Interposed balls 144 are held in position by a V-groove in retaining race 143a, which is integral with race 143.
Device 150 of FIG. 15 is both an axial load and a radial load bearing. The loads are transferred from upper race 151 to balls 152. Axial loads are transferred from balls 152 to lower race 153, which is not directly opposite race 151. The radial loads are transferred through interposed balls 154 to retaining race 153a, which is fastened to lower race 153. In a variation of this device the entire load may be transferred directly to race 153 by shifting its concave surface clockwise so that it contacts balls 152 opposite their points of contact with upper race 151; then balls 154 will carry no load but will only serve to position balls 152.
FIGS. 16, 17, and 18 show devices similar to those of FIGS. 13, 14, and 15 respectively, differing primarily in that the load bearing elements are rollers instead of balls. In FIG. 16, device 160 is a radial load rolling contact bearing in which loads are transferred from outer race 161 through rollers 162 to inner race 163. Balls 164 are interposed between concave end portions of rollers 162 and are held in position by race 161a, which is integral with race 161. Snap rings 165 and 166 prevent axial shifting of the elements.
FIG. 17 shows device 170 which is an axial load variation of device 160. Loads are transferred from upper race 171 through rollers 172 to lower race 173. Balls 174 are interposed between the conically shaped ends of rollers 172 and serve both to separate them and to prevent their radially outward movement. Retaining race 173a is integral with race 173 and holds balls 174 in position.
FIG. 18 depicts device 180, which is essentially a combination of devices 160 and 170. In FIG. 18, both radial and axial loads are transferred between races 181 and 183 through rolling line contact with rollers 182. Interposed balls 184 roll on conical ends of rollers 182 and are held in position by retaining race 181a which is integral with race 181.
All of the rolling contact devices thus far described have interposed rolling elements supported on only one side of the main load bearing elements. The remainder of the devices to be described all have their interposed rotating elements supported on both sides of the major rotating elements, either in the form of rollers which are supported on both sides or as balls located on both sides. It should be noted that there is only one point or line contact between adjacent rotating elements, although more may be possible. The rollers may be in one piece or made up of several parts.
FIGS. 19 and 20 show device 190 which is a radial load rolling point contact bearing in which loads are transferred between outer race 191 and inner race 193 through balls 192. Rollers 194 are placed between rollers 192 to keep them from touching each other. Retaining races 191a are integral with race 191 and are in rolling contact with the reduced diameter ends 194a of rollers 194, holding them radially outwards between rollers 192. Although means are not shown for assembly, this may be accomplished in several ways, such as by making one of the retaining races 191a removable.
All elements will be in rolling contact if the following dimensional relationships are observed: ##EQU3## where D 1 is the inner diameter of race 191 where it contacts balls 192, D 2 is the outer diameter of retaining races 191a where they contact rollers 194a, d 1 is the major diameter of rollers 194, and d 2 is the diameter of roller ends 194a.
Device 210 of FIG. 21 is an axial load variation of device 190 in which balls 212 are in rolling contact with races 211 and 213. Interposed rollers 214 are held in position by races 214a and 215. Rolling contact of all elements is assured if roller 214 is in the shape of a truncate cone perpendicular to the axis of the bearing and whose apex, if extended, would coincide with the axis of the bearing. Bearings intermediate to devices 190 and 210 are quite practical and would result in bearings with both radial and axial load capability.
FIG. 22 depicts device 220 which is a radial load bearing similar to that of device 190, except that the main load bearing elements are rollers instead of balls, and the axes of the intervening minor rollers are located radially outward of the axes of the load bearing rollers instead of radially inward of them. In device 220, loads are transferred from outer race 221 through rollers 222 to inner race 223. Interposed rollers 224 have enlarged ends which are in rolling contact on one side with retaining race 223a on the other side with adjustable retaining race 225. Snap ring 226 holds rollers 222 in position with respect to race 221.
FIG. 23 shows device 230 which is a combination radial and axial load bearing similar to device 220. Loads are transferred between races 231 and 233 through rollers 232. Tapered rollers 234 are located between rollers 232 to keep them apart, and are held in positon by adjustable retaining races 235 and 236. In an axial load variation of this device, rollers 232 and 234 would be oriented horizontally.
Device 240 of FIG. 24 has balls as load bearing elements and instead of rollers to separate them, two series of balls are used, one series on each side. Loads are transferred from outer race 241 through balls 242 to inner race 243. One series of balls 244 is interposed balls 242 on one side and held in position by retaining race 241a, and the other series of balls 224 is interposed between balls 242 on their other side and held in position by adjustable retaining race 245.
FIG. 25 shows device 250 which is similar to device 240, except that it is a combination radial and axial load bearing. Loads are transferred from race 251 through balls 252 to another race 253. Balls 252 are separated on one side by a series of balls 254 which also roll in a V-groove on the inner hub of race 253 and are held in position therewith. A second series of balls 254 is interposed between balls 252 on their upper side, this series of balls being held in position by their contact with a concave groove in adjustable retaining race 255.
Device 260 of FIG. 26 is an axial load rolling contact bearing smilar to devices 240 and 250, except that the load bearing elements are rollers instead of balls. Loads are transferred from race 261 through rollers 262 to race 263. Balls 264 rotate between the outer ends of rollers 262 and are held in position by V-grooved adjustable retaining race 266. Balls 265, which are shown as smaller in size than balls 264 but could be the same size, rotate between the inner ends of rollers 262 and are held in position by another V-grooved retaining race which is shown as integral with race 263.
Radial and axial load bearings similar to device 260 may be had by shifting the angle of the axes of rollers 262 with respect to the axis of the bearing, and by changing the locations of the other elements to suit. | Rotary radial and axial load bearing devices in which loads are transferred from a race through circularly disposed rotating elements to a second race. Secondary rotating elements are interposed between the load bearing rotating elements to prevent their mutual contact and are in turn held in position by retaining rings fastened to the race opposite their location. All elements are in rolling contact only, so friction is minimized. In some of the devices, secondary rotating elements may carry part of the load; others are capable of rolling contact speed changes. | 5 |
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to the significant reducing of the dynamic loads produced by earthquake, vibration, or collision. The present invention prevent structure failures for subjects, such as electrical boxes on top of bridges, or any important instruments that subject dynamic loads induced by earthquake, truck traffic, sudden acceleration or collision.
[0003] 2. Description of the Related Art Including Information
BRIEF SUMMARY OF THE INVENTION
[0004] Since vibrations created by the heavy trucks, earthquakes, vibrations, or collisions induce significant dynamic force to the supports of an object; an isolation supporting system is proposed to reduce the dynamic impact to the supporting system and instrument itself. The system is isolated through four spring supports from bottom of the object.
[0005] At the same time, dampers are attached between the supporting structure and the instrument vertically and horizontally. The functions of the dampers are to convert the kinetic energy of the system to the heat energy through a special liquate confined inside of the dampers. The manufacture claims that the damper can create 50% of the damping factor. The dynamic loads of the object are substantially reduced by the combination of spring and damper system.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
[0006] The invention is better understood by reading the following Detailed Description of the Preferred Embodiments with reference to the accompanying drawing figures, in which like reference numerals refer to like elements throughout, and in which:
[0007] FIG. 1 illustrates a front elevation view of the shock absorbing support system with springs and dampers at bottom and dampers at the top portion according to the present invention.
[0008] FIG. 2 illustrates a side elevation view in cross-section of the shock absorbing support system with springs at bottom and damper at the top portion.
[0009] FIG. 3 is a schematic damper location plan, top view of the shock absorbing support system.
[0010] FIG. 4 is a schematic spring and damper location plan, bottom view of the shock absorbing support system.
[0011] FIG. 5 is an enlarged elevation view of damper and spring assemble at the bottom support.
[0012] FIG. 6 is an enlarged elevation view of damper assemble at the top support.
[0013] FIG. 7 is an enlarged view of the spring assembles in FIG. 1 .
[0014] FIG. 8 is an enlarged view of the damper assembles in FIG. 1 .
[0015] FIG. 9 is an enlarged view of the damper support in FIG. 1 .
[0016] FIG. 10 is an enlarged view of the pin and retaining ring for the damper support in FIG. 1 .
[0017] FIG. 11 is a flow chart of model analysis
DETAILED DESCRIPTION OF THE INVENTION
[0018] In describing preferred embodiments of the present invention illustrated in the drawings, specific terminology is employed for the sake of clarity. However, the invention is not intended to be limited to the specific terminology so selected, and it is to be understood that each specific element includes all technical equivalents, which operate in a similar manner to accomplish a similar purpose.
[0019] Referring initially to FIG. 1 , a preferred embodiment of the shock absorbing support system is shown. Vertical members 7 sit on a horizontal member 8 that is fixed attached to a structure that has vibration source. Horizontal members 6 sit on the vertical members 7 . The horizontal members 6 function as a platform that supports the instrument 3 . The vertical upper members 4 are fixed attached to the horizontal members 6 . Rigid frame 5 functions as a cage that hold the instrument 3 . Between the frame 5 and horizontal platform, springs 1 and dampers 2 isolate the instrument 3 from the support 7 and 8 . Upper end of members 4 are connected to upper portion of frame 5 through several dampers 2 .
[0020] In the FIG. 2 , a preferred embodiment side elevation of the shock absorbing support is shown. Vertical beams 7 sitting on horizontal member 8 support the platform 6 . Springs 1 isolating instrument 3 from the vibration source are guided through steel rods 20 . Steel rods 20 prevent instrument 3 vibrate erratically without restrains. Vertical dampers 2 at the bottom support of instrument 3 convert vertical kinetic energy of the vibration into heat energy dissipated to the surrounding atmosphere. Thus the vertical load from instrument 3 transfer back to the supporting system is significantly reduced. Horizontal dampers 2 at the top portion of instrument 3 connecting instrument 3 to vertical members 4 convert the horizontal kinetic energy into the heat energy dissipated to the surrounding atmosphere. Thus the horizontal load from instrument 3 transfer back to the supporting system is significantly reduced.
[0021] FIG. 3 shows a preferred embodiment with schematic location of top horizontal dampers 2 in two directions of horizontal plain. Horizontal dampers can transfer horizontal vibrating energy (kinetic energy) into heat energy from any horizontal direction in this configuration. There are no dampers 2 at front face 10 of instrument 3 because instrument 3 can be removed or installed from the system. At back face 9 , dampers 2 are attached to instrument 3 . Two section views are shown in FIG. 1 and FIG. 2 .
[0022] FIG. 4 shows a preferred embodiment with schematic location of bottom vertical dampers 2 and springs 1 at each bottom corner of instrument 3 . Vertical springs 1 isolate the system from the vibration source and support the weight and dynamic load of instrument 3 . Vertical dampers 2 can transfer vertical vibrating energy (kinetic energy) into heat energy in this configuration. Two section views are shown in FIG. 1 and FIG. 2 .
[0023] Members 6 provide a platform for springs 1 and dampers 2 . In FIG. 5 , bottom of steel rods 20 are welded to members 6 . Spring coils 21 are placed around steel rods 20 as shown in FIG. 7 . Top of steel rods 20 is free standing. Plate 14 welded to member 12 of instrument rigid frame 5 . A hole in the center area of plate 4 is large enough to let steel rods 20 through and some room for lateral movement. Steel nuts 23 lock steel rods 20 after steel rods 20 go through the hole of plate 14 .
[0024] By the side of springs 1 , dampers 2 are connecting members 6 and members 12 through damper mounting assemblies 10 . Damper mounting assemblies 10 are welded or bolted to members 6 and members 12 . Dampers 2 are pined to damper mounting assemblies 10 by pin assembles 31 . Pin assembles 31 are composed of steel rods 51 with two recesses for retaining ring at each end and locked by retaining rings 52 in FIG. 10 .
[0025] FIG. 6 shows a preferred assemble of horizontal dampers 2 . Damper mounting assemblies 10 are welded or bolted to members 4 and members 41 . Members 41 are part of rigid frame 5 . FIG. 8 shows a typical damper, which is preferred to be manufactured by Taylor Devices Inc. FIG. 9 shows a preferred damper mounting assemblies 10 . Damper mounting assemblies 10 are composed by steel u frame 30 , two shim plates 32 , and pin assembles 31 .
[0026] The requirement for a dynamic analysis often leads to a direct need by the engineer for a sophisticated general-purpose computer software system such as GTSTRUDL. GTSTRUDL permits the engineer to utilize all of the member, finite element, graphical display, and steel design features available in static analysis in conjunction with the dynamic analysis capabilities in those structures subjected to strong wind, seismic, heavy truck traffic, or vibrating machinery loadings. Using combinations of these features, dynamic analysis results may be obtained for a large variety of structures and loading conditions.
[0027] The dynamic analysis of the shock absorbing support system can best be summarized by FIG. 11 . First geometry (Joint coordinates) 101 of the system is input into the computer. Topology (member and finite element incidences), support boundary conditions, member and finite element boundary conditions, material properties, and member and finite element properties 102 are also needed for the input. Dynamic information, such as structure damping and dynamic loadings (time history or spectrum) 103 , may be collected from the field or from lab experiment. If the dynamic loading is from time history, it can be converted to spectrum 104 .
[0028] Static loads 108 are inputted to perform static analysis 109 . The static analysis result 112 can be outputted independently from dynamic output 107 . With dynamic data 103 , computer first perform eigensolution without initial stress 105 , then dynamic analysis through one of the following method: (1) Response spectrum analysis (Including Missing Mass, Base Shear, and Shear Wall Analysis calculations) or (2) transient time history analysis 106 . After the dynamic analysis 106 , the program creates pseudo static loading 111 results from dynamic analysis results. Dynamic analysis results such as dynamic data output, eigensolution results output, response spectrum analysis results output and transient analysis results output 107 can be outputted independently. Program combines static analysis result 112 and dynamic analysis results 107 into shock result 113 . After the combination, program also can perform member design and/or code checking 114 .
[0029] The dynamic analysis is based on the following theories. The dynamic equilibrium equation may be written in the following matrix form:
[ M]{a}+[C]{v}+[K]{x}={F ( t )} (1-1)
where [M], [C], AND [K] are matrices representing the mass, damping, and stiffness of the structure, respectively. The vectors {a}, {v}, and {x} represent the acceleration, velocities and displacement of the joint degree of freedom. The vector {F(t)} represents the applied transient forces.
[0030] Response spectrum analysis is an approximate method of dynamic analysis that uses the know response of single degree of freedom systems with the same natural frequency and percents of critical damping as the modes of vibration of the structure being analysis when subjected to the same transient loading.
[0031] For applied support acceleration,
{ F ( t )}=−[ M]{E}a G ( t ) (1-2)
Where,
a G (t) is the time dependent support acceleration {E} is a vector containing one's for degrees of freedom in the direction of the applied ground motion and zeroes otherwise.
[0034] Then
{ a t ( t )}={ a ( t )}+{ a G ( t )} (1-3)
[0035] Where,
a t (t) contains the total acceleration where the subscript t indicates total a(t) contains the nodal point acceleration relative to the supports
[0038] Therefore,
[ M]{a t }+[C]{v t }+[K]{x t }=−[M]{E}a G ( t ) (1-4)
[0039] As in the modal analysis method, the equation of motion must be uncoupled and transformed to normal coordinates for the response of each mode to be calculated. In a modal time history analysis, Eq. 1-4 would be solved in order to evaluate the response at each time step. However, in a response spectrum analysis, it is assumed that we know the maximum value of the integrals from either previous computation or experimental results.
[0040] Once the maximum response for each mode is obtained, the maximum total response must be computed. GTSTRUDL computes response spectra maximum response by combining the modal responses by seven different approaches. These seven methods are root mean square, absolute summation, peak root mean square, complete quadratic combination, nuclear regulatory commission grouping method, nuclear regulatory commission ten percent method, and nuclear regulatory commission double sum method. Each of the seven combination techniques may be performed for each response spectra loading condition. In addition, the root mean square method may be used to combine the results of two or more response spectra loadings, which may represent statistically independent dynamic components.
[0041] An instrument with 800 pounds of static load was modeled with vibration generated by heavy truck load using this shock absorbing support system. A model without this system is also analyzed. The next table shows the juxtaposition of two models. It demonstrates the system with dampers and springs has significant advantages over the model having no dampers and springs.
COMPARISON OF RESULTS w/ springs w/o springs Model and dampers and dampers Acceleration 148.5 in/sec{circumflex over ( )}2 614.64 in/sec{circumflex over ( )}2 At vertical direction Acceleration 60.5 in/sec{circumflex over ( )}2 250.4 in/sec{circumflex over ( )}2 At horizontal direction Velocity 8.9 in/sec 11.69 in/sec At vertical direction Velocity 5.7 in/sec 4.76 in/sec At horizontal direction Max. stress of support 0.168 ksi 3.9 ksi member Max. dynamic force of 176 lbs 703 lbs support member Max. dynamic force at each 102 lbs 356 lbs VMS box support | A Shock absorbing support system isolates vibrations that would otherwise pass through the important instrument mounted on the vibration source. The isolation includes springs and dampers under the bottom of the instrument while dampers around tops of the instrument. The combination of the springs and the dampers results in a dissipation of kinetic energy caused by vibrations that would otherwise pass through the instrument and cause significant dynamic load and damages to the support and the instrument. | 4 |
BACKGROUND OF THE INVENTION
NOTICE OF INTENT TO RESERVE COPYRIGHT OR MAST WORK RIGHTS
[0001] Not Applicable.
CROSS-REFERENCE TO RELATED APPLICATIONS
[0002] Not Applicable.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0003] Not Applicable.
[0004] REFERENCE TO SEQUENCE LISTING A TABLE, OR A COMPUTER PROGRAM LISTING COMPACT DISC APPENDIX
[0005] Not Applicable.
BACKGROUND OF THE INVENTION
[0006] Pipe fencing is very popular due to its durability and adaptability to many situations/uses. During fabrication, a plurality of posts are placed in the ground at intervals to support the railing. Horizontal railing is then used to span the gaps between the posts.
[0007] A single railing connects one or more posts to create a barrier and to add structural support. Pipes come in lengths as long as 40 feet and can weigh more than 300 lbs., making precise alignment difficult, and requiring several people to properly position and secure each rail.
[0008] In one common form of pipe fencing, the rails are attached along the front face of the post. In this configuration, the central axis of the rail is oriented perpendicular to the central axis of the post. These axes are offset by a distance of the combined radii of the post and rail, placing the two outer walls of the pipe in proximity, and then joining the pipes in such configuration. This configuration is referred to as a lap joint.
[0009] In another common configuration of the pipe fencing, the rails are attached to the sides of the post. In this configuration, the central axis of the rail is oriented perpendicular to the central axis of the post, and these central axes intersect at the approximate center of the joint location. The walls of the post and/or rail are often drilled, notched, cut, or otherwise shaped to reduce gap space in the joint. This configuration is referred to as a butt joint.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 illustrates a front view of typical construction for a welded pipe fence.
[0011] FIG. 2 illustrates a side view of typical construction for a welded pipe fence.
[0012] FIG. 3 illustrates a positioning bracket in accordance with an exemplary embodiment of the innovation.
[0013] FIG. 4 shows an alternative positioning bracket in accordance with an exemplary embodiment of the invention.
[0014] FIG. 5 shows the positioning bracket installed to position a butted rail for securing in accordance with the teachings herein.
[0015] FIG. 6 shows the positioning bracket installed to position a spanning rail for securing in accordance with the teachings herein.
[0016] FIG. 7 shows an alternative embodiment of the positioning bracket in accordance with the teachings herein.
[0017] FIG. 7A shows the attachment of the body to the clamp, in place of force binders, in the alternative embodiment of FIG. 7 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0018] Described herein is an apparatus and method of use which allows repeatable, precise positioning of the railing by a single individual. A single clamp may be used to quickly and temporarily support one end of a pipe railing at the correct height so a worker may position and secure the distal end. A plurality of clamps may be utilized to position the pipe along its length at multiple points so a worker is free to secure the railing to the post or make positioning adjustments.
[0019] In one implementation, the body of the positioning brackets is secured to a plurality of posts at a specific height. In the case of long railing, that span more than a single post interval, positioning brackets may be used at each end and additional positioning brackets may be used on central posts to prevent the rail from sagging under its own weight.
[0020] Once the positioning brackets are placed and secured, the railing is lifted onto the positioning brackets. The railing may then be moved horizontally in the positioning brackets to allow precise alignment. Once aligned, the rail is secured to the post. In the preferred embodiment securing the rail to the post is accomplished by welding. One skilled in the arts would appreciate that other methods could be employed such as, but not limited to, bolting, screwing, drilling, pegging, and slotting, or by employing adhesives.
[0021] The positioning bracket allows precise, repeatable positioning, because the top of the positioning bracket's body is always secured at a designated offset from the rail's resting position.
[0022] In the preferred embodiment, the rail support projects from the body proximately even with the top of the body. The rail will be supported on the top of the rail support for a lap joint; therefore, the positioning brackets should be positioned with the top of the body aligned with the bottom of the rail's desired position.
[0023] Railing will be supported on the butt support for a butt joint; therefore, the positioning brackets should be positioned with the top of the body a precise distance below the bottom of the rail's desired position. The precise distance depends on the positioning bracket's actual construction.
[0024] FIGS. 1 & 2 illustrate a typical construction for a welded pipe fence. Posts ( 10 ) are placed in the ground ( 30 ) at intervals. The intervals between posts ( 10 ) are spanned by rails ( 20 ). Top rails ( 20 A) are traditionally secured on top of posts ( 10 ) with a notched lap joint ( 70 A) and secured with a welded seam ( 80 ) to ‘finish’ the top of the post ( 10 ) without requiring a cap or other ‘closing’ of the post ( 10 ) top. One or more rails ( 20 ) may then be added below the top rail ( 20 A), depending on the fence's intended uses. These rails ( 20 ) may be butted rails ( 20 B), or spanning rails ( 20 C).
[0025] Butted rails ( 20 B) are cut and optionally notched to fit the interval between the posts ( 10 ). The butted rails ( 20 B) are joined to the posts ( 10 ) with a butt joint ( 50 ) where the ends of the rails ( 20 ) are notched to join the sides of the post ( 10 ) and then welded ( 80 ) into place.
[0026] Spanning rails ( 20 C) extend beyond the intervals between the posts ( 10 ) and therefore are positioned against the inside or outside of the fence. The outer wall of the spanning rail ( 20 C) is positioned against the outer wall of the post ( 10 ) at the desired location and the two are joined producing a lap joint ( 70 ). In the preferred embodiment, the joining is accomplished by a weld ( 80 ).
[0027] FIG. 3 illustrates the preferred embodiment of the positioning bracket. The bracket ( 100 ) comprises a body ( 110 ) and a door ( 130 ) connected by a hinge ( 120 ), which allows the bracket to encompass the post ( 10 , not shown) by use of a clamping mechanism ( 90 , not shown), which secures against the force binders ( 140 ). One skilled in the arts would appreciate that vice clamping is utilized because the vice clamps are a mainstay of a typical welding kit. However, other mechanisms can be utilized to secure the bracket to the post such as, but not limited to, chaining, screws, spring clamps and levered closers.
[0028] From the top edge of the body ( 110 ), a rail support ( 150 ) extends such that it will be substantially perpendicular to the position of the post. The end of the rail support ( 150 ) distal to the body ( 110 ) curves upward and ends in a butt support ( 160 ), which optionally includes extended butt supports ( 160 A).
[0029] FIG. 4 shows an alternative positioning bracket in accordance with an exemplary embodiment of the invention. The bracket comprises a body ( 110 ) and a door ( 130 ) connected by a hinge ( 120 ), which allows the bracket to encompass the post ( 10 , not shown) by use of a clamping mechanism ( 90 , not shown), which secures against the force binders ( 140 ). In this embodiment, the body ( 110 ) and the door ( 130 ) are substantially similar in construction, but are differentiated by the rail support ( 150 ) which extends from the top edge of the body ( 110 ). In this embodiment, the force binders ( 140 ) are significantly larger making it easier to apply multiple clamps for additional holding power.
[0030] As in the previous design, a rail support ( 150 ) extends from the top edge of the body ( 110 ), such that it will be substantially perpendicular to the position of the post. In the preferred embodiment, this rail support ( 150 ) is angled slightly upward to cause the rail to naturally roll back toward the post. The end of the rail support ( 150 ) distal to the body ( 110 ) curves upward and ends in a butt support ( 160 ), here shown without the optional extended butt supports ( 160 A).
[0031] FIG. 5 shows the positioning bracket installed to position a butted rail for securing in accordance with the teachings herein. The positioning bracket ( 100 , not labeled) is secured to the post ( 10 ) with a butted rail ( 20 B), supported by the extended butt support ( 160 & 160 A).
[0032] FIG. 6 shows the positioning bracket installed to position a spanning rail for securing in accordance with the teachings herein. The positioning bracket ( 100 , not labeled) is secured to the post ( 10 ) with a spanning rail ( 20 C), supported by the rail support ( 150 ). A slight upward angle to the rail support ( 150 ) causes the rail ( 20 ) to naturally rest against the post ( 10 ) to facilitate joining.
[0033] FIG. 7 shows an alternative embodiment of the positioning bracket in accordance with the teachings herein. In the alternative embodiment, there are two bodies ( 110 ) and no door ( 130 ). The bodies ( 110 ) are NOT joined by the hinge ( 120 ). Instead, they are pivotally mounted on the “jaws” of the clamping mechanism ( 90 ). This alternative arrangement allows for single handed application of the clamp to the post ( 10 , not shown). The rail support ( 150 ) on each body, with the curved upward butt support ( 160 ) distal to the body ( 110 ) still functions in the same way as previously defined. In an alternative embodiment, one of the bodies ( 110 ), which face each other on opposite sides of the post, may be circumrotated 180 degrees such that one rail support ( 150 ) points up, and the other points down. This ensures that anytime the clamp is installed on the post, the rail supports ( 150 ) are positioned correctly due to the mirrored orientation.
[0034] FIG. 7A shows the attachment of the body to the clamp in place of force binders in the ° alternative embodiment of FIG. 7 . The jaws of the clamp ( 90 ) are pivotally attached to the body ( 110 ) via brackets ( 210 ). In the preferred embodiment, there are two parallel brackets ( 210 ) extending perpendicular from the rear of the body ( 110 ) and spaced to allow the jaws of the clamp ( 90 ) to be positioned there between. A fastener ( 220 ) is positioned through the brackets ( 210 ) and the clamp ( 90 ) to allow rotation. In one embodiment, the rotation may be limited to ensure the faces of the bodies ( 110 ) always remain oriented toward center.
[0035] The diagrams, in accordance with exemplary embodiments of the present invention, are provided as examples and should not be construed to limit other embodiments within the scope of the invention. For instance, heights, widths, and thicknesses may not be to scale and should not be construed to limit the invention to the particular proportions illustrated. Additionally, some elements illustrated in the singularity may actually be implemented in a plurality. Further, some element illustrated in the plurality could actually vary in count. Further, some elements illustrated in one form could actually vary in detail. Further yet, specific numerical data values (such as specific quantities, numbers, categories, etc.) or other specific information should be interpreted as illustrative for discussing exemplary embodiments. Such specific information is not provided to limit the invention.
[0036] The above discussion is meant to be illustrative of the principles and various embodiments of the present invention. Numerous variations and modifications will become apparent to those skilled in the art once the above disclosure is fully appreciated. It is intended that the following claims be interpreted to embrace all such variations and modifications. | A method of constructing a fence comprising encircling one or more of the posts with supporting brackets which support railing members for securing to the post. The supporting brackets allowing for repositioning of the rail before securing. The supporting brackets further being conducive to welding, drilling, or use of adhesives in securing the railing to the post. | 4 |
BACKGROUND OF THE INVENTION
In the fabrication of transducers, it is frequently necessary to join parts through the use of adhesive. An example of an application of such a transducer is a scale that utilizes a strain gauge for the purpose of measuring the deflection of a beam. The strain gauge must be attached to the beam in such a way that the deflection of the beam is accurately measured by the strain gauge. This requires that the strain gauge be firmly attached to the beam with a minimum of adhesive holding the strain gauge to the beam.
Prior art methods for curing adhesive for bonding a strain gauge to a beam involved applying adhesive to the strain gauge and attaching it to a beam and curing the adhesive. This was accomplished by mechanically clamping the strain gauge to the beam with the adhesive therebetween in a fixture and placing the fixture in a heating chamber which was then brought to the curing temperature of the adhesive. The quality of the transducer is materially affected by the bond line temperature, i.e. the temperature reached by the adhesive. Achieving the proper bond line temperature requires a considerable amount of time so that the temperature of the entire mass may be brought to the curing temperature relatively uniformly. In this scheme of curing, the entire fixture had to be heated.
As is known, it is difficult to control the temperature within a heating chamber, particularly when the heat is supplied by resistance heating. The heat from the atmosphere is transferred to the fixture and the bond line eventually reaches the desired temperature. The shortcoming of this method of curing the adhesive of a transducer is that furnaces, whether they be resistance furnaces or combustion furnaces, do not display either uniform increase in temperature or uniform temperature throughout the chamber. As a consequence, some of the transducers will achieve a proper curing of the adhesive while others will either be cured at too high or too low a temperature. The rate of heat rise also could be too high or too low. Furthermore, a large amount of energy is required in this mass method of curing for the small amount of material that is to be cured. A still further disadvantage is that only when a large number of transducers are being fabricated does the method approach any type of economic justification.
BRIEF DESCRIPTION OF THE INVENTION
A system has been conceived whereby the adhesive used in the bonding of transducer parts may be controlled so as to achieve maximum adherance at a lesser cost. This is accomplished by applying a strain gauge having an adhesive layer on the surface thereof against a transducer body and placing a resilient pad on the opposite side of the strain gauge. This assembly is then placed into a clamping device that is made up of a fixture that backs the transducer body and a shoe that engages the resilient pad with the strain gauge therebetween. The fixture contains heaters and a temperature sensor whereby heat may be applied to the transducer body in a controlled fashion. One of the advantages of this scheme is that the resilient pad which previously acted as an insulator that kept heat away from the strain gauge now acts as an insulator to prevent heat loss and maintain uniform temperature of the adhesive layer.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is an isometric view of a clamping device with which the instant invention may be practiced;
FIG. 1a is a cross-sectional view taken along the lines 1,1 of FIG. 1;
FIG. 2 is a cross-sectional view of a portion of the clamping device shown in FIG. 1 with a transducer assembly disposed therein;
FIG. 3 is a block diagram of the circuitry used to supply and control heat to the assembly shown in FIG. 2;
FIG. 4 is a schematic diagram of the clock generator shown in FIG. 3;
FIG. 5 is a schematic diagram of the initializing circuit shown in FIG. 3;
FIG. 6 is a schematic diagram of the interval timer and cycle counter of the system shown in FIG. 3;
FIG. 7 is a schematic diagram of the interval counter shown in FIG. 3;
FIG. 8a is a schematic diagram of the cycle gating shown if FIG. 3;
FIG. 8b shows the mode control and temperature detector shown in FIG. 3; and
FIG. 8c is a schematic diagram of the heater driver shown in FIG. 3.
FIG. 9 is a graph showing the relationship between time and temperature of the curing cycle.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to FIGS. 1 and 1a a clamping device is shown generally at 10 and includes a base 12 having an opening 14 therein. A block 16 is secured to the base 12 as by bolts 18 (only one being shown) adjacent to the opening 14. A fixture 20 is received within the opening 14 as is an insulator 22 and the two are secured to the block 16 as by bolts 24 (only one being shown). The fixture 20 extends well above the base 12 and has electric heating elements 26 to which leads 27 are attached and a temperature sensing device 28, such as a thermocouple or thermistor, to which a lead 29 is attached. The fixture 20 is made of a material, such as stainless steel, with high thermal conductivity. The insulator 22 is made of an insulating material, such as phenolic or ceramic, that acts to reduce heat losses from the fixture 20.
Addressing the fixture 20 is a buttress 30 that is secured to the base 12 by bolts 32. A plank 34 may be first welded to the base 12 so as to assure alignment of the buttress 30. The buttress 30 has an opening 36 therein that receives a plunger 38. The plunger 38 has a collar 40 thereon and is partially received within a sleeve 42 that is attached to a threaded shaft 44. An internally threaded collar 46 is disposed upon the threaded shaft 44 as is a nut 48 that secures the position of the collar 46. Also disposed upon the threaded shaft 44 is a second nut 50. A spring 52 is disposed about the sleeve 42 and a portion of the plunger 38 intermediate the collars 40,46.
A bracket 54 is secured to the base 12 by bolts 56. The bracket 54 has an opening 58 therein with a cylindrical guide 59 intergral therewith. A piston 60 is received within the guide 59 and extends through the opening 58. The piston 60 has a slotted end 62 that receives an arcuate arm 64. The arcuate arm 64 is supported within the slot 62 by a pin 66. A handle 68 has an elongated slot 70 that receives a projection 72 of the bracket 54. The handle 68 is pivotally mounted to the projection 72 by pin 74 and the arcuate arm 64 is pivotally supported by the handle by another pin 76. This construction allows the plunger 38 to be moved toward and away from the fixture 20 by pivoting the handle 68 in a clockwise or counter-clockwise direction, respectively. The plunger 38 will be locked when the handle 68 is in its maximum clockwise position.
Referring now to FIG. 2, a transducer body 78 to which a strain gauge is to be attached is placed next to the fixture 20. A layer of adhesive 80 is applied to the transducer body 78 and a strain gauge 82 is placed over the adhesive layer. A resilient pad 84 is located between the strain gauge 82 and a force, transfer shoe 86. The plunger 38 is applied against the force transfer shoe 86 by movement of the handle 68 to its most clockwise position with a resilient force sufficiently great to hold the various components 78, 80, 82, 84 and 86 firmly against one another. The resilient holding by the plunger 38 is occasioned by the presence of the spring 52.
Referring now to FIG. 3, a block diagram is shown of the circuitry used to control the heat applied to the fixture 10 so as to cure the adhesive layer 80 in what is believed to be the most advantageous manner. A temperature detector 89, which includes the temperature sensing device 28, is in electrical connection with a mode control unit 88 that may be a microprocessor such as an Intel 8085. The heating elements 26 are part of a heat driver 87 that is also connected to the mode control unit 88. In addition, a cycle gating unit 90 is in electrical connection with the mode control unit 88. Timing signals are generated by a clock generator 92 that is in connection with an interval timer and cycle counter 94. An interval counter 96 receives the output of the interval timer and cycle control unit 94 and is connected to an initializer 98. The interval counter 96 is connected to the cycle gating unit 90 so as to control the cycling of the system. The clock generator 92 generates a timing signal with every zero crossing of the cycle. The clock rate is preferably 120 hertz.
This timing signal is sent to the interval timer and cycle counter 94 that divides the line current into 32 segments. The cycle counter portion of the interval timer and cycle unit 94 counts from 1/32nd to 31/32nds, depending upon the adjustment, and determines the interval that is to be used. The interval counter 96 determines the status of the cycle counter 94 and selects the interval required. The initializer 98 is the start/stop controller and initializes the counters 94,96.
The cycle gating 90 controls the heating rate by sending the appropriate gate signal in terms of the segment to be applied. This gate signal is directed to the mode control unit 88 that acts upon the heater driver 87. The temperature detector 89 determines the temperature of the material and supplies the information to the mode control 88 so that the power supplied to the heater driver may be controlled after a predetermined temperature is attained. More specifically, when the temperature is reached for optimum curing of the adhesive layer, the power will be controlled to maintain this temperature within pre-set limits.
Referring now to FIG. 4, details are shown of the clock generator 92. A zero crossing detector 100 receives AC through lines 102 and sends a signal to an optocoupler 104. The output transistor 105 of the optocoupler 104 is in connection with the voltage source 106 and acts as a conditioner for the signal received from the zero crossing detector 100. A one shot multivibrator 108 receives the output of the transistor 105 to generate clock pulses CLK and CLK and is in contact with a one shot multivibrator 110.
Referring now to FIG. 5, details will be given of the initializer 98 which includes a flip-flop 114 which is connected to the source of power 106. When power is first supplied, the flip-flop 114 is forced into the reset state by an R-C circuit 116. This results in INIT being low and INIT high; this sets the counters, shift registers and flip-flops to the state desired for non-operating condition. When the start line is brought low, the flip-flop changes state, INIT is high, INIT is low and the cycle starts. The cycle is stopped by an external stop switch that is either manual or activated by a timer.
The output of the one shot multivibrator 108 is connected to the interval timer and cycle counter 94 to provide the clock signal as seen in FIG. 6. The clock output and the signal INIT from the initializer 98 are received by a shift register 118 which divides the cycle into 32 segments. The 32 segments are shown as 2 0 , 2 1 . . . 2 4 which combinations will yield every segment from 1 to 32. The output of the shift register 118 is received by flip-flop 122 and 124 via an inverter 126. The shift register 118 and flip-flops 122 and 124 form an interval timer whose output drives a shift register 128. This shift register 128 is wired to allow one of its eight outputs to be brought to the input of a one shot multivibrator 132 (FIG. 7) which advances shift registers 140 and 144 to successive intervals. The Q outputs of a pair of one shot multivibrators 132,136 are connected to an OR gate 138 which connects to the inputs of the shift registers 140,144. The selected output of shift registers 140,144 determines the length of the interval for each power level. A flip-flop 142 initializes the shift registers 140,144 and another flip-flop 146 serves as an interval counter. These two flip-flops 142,146 allow half the number of segments to be processed in each cycle of the shift registers 140,144. The shift registers 140 and 144 will determine the segments 1-16 in the first cycle and are then used to determine the intervals 17 through 32 i.e. 16+1, 16+2, etc. in the next cycle.
Referring now to FIG. 8, the cycle gating unit 90 includes a decoding circuit that is made up of a number of AND gates 148-1 to 148-4 and OR gates 150-1 to 150-10 that receive signals from the interval timer and cycle counter 94 and from self generated signals as indicated. The outputs from these AND gates 148-1 to 148-4 and OR gates 150-1 to 150-10 are supplied to NAND gates 152-1 to 152-15 as are timing signals EN 1 to EN 15 , the appropriate signal from one of these NAND gates being supplied to an inverter 154. Receiving the output from the inverter 154 is an AND gate 156 that also receives the output at one of its terminals from another inverter 158 that receives the output of the 2 4 pin of the shift register 118. The 2 4 output of counter 118 is also in contact with another AND gate 160 that also receives the output from the Q pin of the flip-flop 146 of the interval counter 96. As a result of this construction, the AND gate 156 will only output a signal when one of the NAND gates 152-1 to 152-15 outputs a negative signal and the pin 2 4 is low. When 2 4 goes high, then the AND gate 160 will be enabled when in phase with the output from the flip-flop 146. The outputs from the AND gates 156,160 are connected to an OR gate 162.
The output of the OR gate 162 is received by the mode control unit 88 and the temperature detector 89. The mode control unit 88 is made up of a pair of AND gates 166,168 the outputs of which are connected to a NOR gate 170. The other inputs of the AND gates 166,168 are provided by the clock generator 92 and by the temperature detector 89. The temperature detector 89 includes the temperature sensing device 28 that is connected to an operational amplifier 172, the output of which is directed to an inverter 174. The output of the inverter 174 is connected to a terminal of a flip-flop 176 whose Q output is received by the AND gate 168 and whose Q output is received by the AND gate 166. The output from the NOR gate 170 is directed to an optocoupler 178 that is connected to an output transistor 180. The output transistor 180 is in connection with a triac 182 which in turn is connected to the heating elements 26.
Consequently, what is shown is a system wherein the temperature of the transducer body is measured by the temperature sensing device 28 and the temperature detector 89 sends a signal indicative of the temperature to a mode controller 88. After the predetermined temperature is reached, the temperature sending device will change the state of the flip-flop 176 and put the mode controller 88 into the mode control to control the cycle gating unit 90 which in conjunction with the interval time and cycle counter unit 94 will output time increments to the heater driver 87. These time increments will vary from 1/32nd to 31/32nds depending upon the temperature of the transducer body 78 and heat losses. In this way, an accurate temperature and length of heating cycle will be maintained. Preferably, the temperature of the transducer body 78 is maintained at 300° F. ±5° F.
The relationship between time and temperature is shown in the graph of FIG. 9. The heating elements 26 are turned on by increasing the power incremently. The incremental increase in power is continued until the temperature measured by the temperature detector reaches a selected level, in this case 300° F. The power is then applied in an interrupted fashion between full power and no power so as to maintain the temperature between approximately 290° F. to 320° F. The temperature will reach the curing temperature of approximately 300° F. in somewhat less than 30 minutes which is the preferred rate of heat rise. It has been found that this has resulted in a strong bond when this rate of heat rise is followed by a heating period of approximately five minutes. Thereafter, the power is turned off and the assembly will cool as shown in the graph. | A method of curing adhesive applied between a strain gauge and a transducer body. The method includes the steps of placing the transducer into contact with a fixed member, applying adhesive to a strain gauge and pressing the adhesive coated strain gauge on the transducer body while heating the fixed member. Heating is provided for by controlling the heat supplied to the fixed member so as to maintain the member at a predetermined temperature. | 2 |
TECHNICAL FIELD
[0001] The invention relates to safety pressure relief devices, and more particularly to reverse buckling discs which are designed to rupture reliably at relatively low pressures.
BACKGROUND
[0002] It is conventional practice to provide reverse buckling discs comprising an annular peripheral flange portion bounding an integral concave/convex dome portion, the disc being provided with one or more scores positioned to encourage opening of the disc on reversal thereof.
[0003] A currently preferred position for the score is around the dome portion adjacent the transition region between the dome portion and the flange portion, such a score being in a position of relatively high stress, and providing maximum free flow area for fluid subsequent to tearing of the collapsed reversed dome portion along the score.
[0004] Manufacture of such reverse buckling discs, however, poses a number of problems, both economical and practical.
[0005] One current method of manufacture is, with reference to FIG. 1 , to provide a pre-form 2 incorporating a hemisphere the shape of which conforms with that of the dome portion 4 of the desired disc, to form the dome portion 4 of the disc in the pre-form 2 , and then to score the dome portion 4 with an associated blade 6 whilst the dome portion is supported in the pre-form 2 .
[0006] However it is necessary to provide separate tooling for each and every deliverable range of burst pressure of disc, which is clearly financially impractical.
[0007] Alternative known methods are shown in FIGS. 2 to 4 , FIG. 2 showing a pre-form 8 which can be used for a range of anticipated dome heights all of which are less than that of the hemisphere 10 provided in the pre-form 8 . Thus the dome portion 12 of the formed disc terminates below the hemisphere 10 , and the scoring is effected by a score blade 14 . However, scoring of the dome portion 12 in this manner can, as shown in FIG. 4 , damage the dome portion by distorting the unscored reverse of the dome portion 12 , which leads to an unreliable product and underlying issues in respect of:
repeatable performance low product yield range limitation reduced in-service cycle life high maintenance costs for tooling inability to produce a specific burst pressure high production costs.
[0015] FIG. 3 shows an annular pre-form or anvil 16 with a chamfered or angled lower inner region 18 for accommodating a range of discs in a similar manner to the pre-form of FIG. 2 , such an arrangement suffering from the same disadvantages detailed above in respect of FIG. 3 .
SUMMARY OF THE INVENTION
[0016] It would be desirable to be able to provide reverse buckling discs and a method of manufacture thereof which resulted in reliability of the discs over a wide range of deliverable burst pressures, sizes and materials in a more economical manner than heretofore.
[0017] According to one aspect of the present invention there is provided a safety pressure relief device comprising an annular flange portion, a concave/convex dome portion and a transition portion between the flange portion and the dome portion, characterised in that the transition portion comprises a linear extent extending from the annular flange portion at a first acute angle to the plane of the flange portion, a tangent to the dome portion at its junction with the transition portion making a second acute angle with the plane of the flange portion which is greater than said first angle, a line of weakness being formed in and around part at least of the linear extent of the transition portion.
[0018] In a preferred embodiment of the invention, the transition between the linear extent and the dome portion is radiused, while it is further preferred that the transition between the linear extent and the flange portion is angular.
[0019] Conveniently the first acute angle is between 20° and 50°, preferably 35°, while the value of the second acute angle exceeds that of the first acute angle by at least 1° up to a maximum of about 40°.
[0020] According to a further aspect of the invention there is provided a method of manufacturing a safety pressure relief device as defined above, the method comprising the steps of providing an annular pre-form having a lower surface thereto, the circumferential inner corner of the pre-form being chamfered to provide a flat surface extending at an acute angle to the plane of the lower surface of the pre-form, locating a circular disc blank with the outer regions thereof abutting, to be supported by, the lower surface of the pre-form, applying pressure to the disc blank to form a concave/convex dome portion within the hollow interior of the pre-form, an intermediate portion of the disc blank being urged against said flat surface of the pre-form to form a linear transition extent to the disc, and forming a line of weakness in and around part at least of the linear extent whilst said extent abuts said flat surface.
[0021] It will be appreciated that, by forming the line of weakness, conveniently a score, in the linear extent of the disc while that extent is supported by the pre-form, any damage to the disc during scoring is eliminated.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIGS. 1 to 4 illustrates prior art arrangements detailed above;
[0023] FIG. 5 shows a reverse buckling disc according to the invention;
[0024] FIG. 6 illustrates the production of the disc of FIG. 5 ,
[0025] FIGS. 7 a and 7 b show two alternative discs according to the invention;
[0026] FIG. 8 is a detail of FIG. 5 illustrating load application to the scored area of the disc;
[0027] FIG. 9 is a detail of FIG. 6 ;
[0028] FIG. 10 is a detail of FIG. 5 to a larger scale, and
[0029] FIG. 11 is a diagrammatic representation of comparative performance changes for a given material and type for prior art discs and discs according to the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0030] Referring to FIGS. 5 to 11 , the reverse buckling disc according to the invention is illustrated generally at 20 and comprises a flat annular flange portion 22 , a concave/convex dome portion 24 and an intermediate transition region 26 including a linear extent 28 making an acute angle θ 1 with the plane of the flange portion 22 , there being a sharp corner 30 between the linear extent 28 and the flange portion 22 . The transition region 26 further includes a radius 32 blending into the dome portion 24 , there being a positive transition between the region 26 and the dome portion 24 —i.e. the tangent to the dome portion 24 at its junction with the transition region 26 makes an acute angle θ 2 with the plane of the flange portion 22 that is greater than the angle θ 1 .
[0031] A circular score (not shown) is formed in the face of the linear extent 28 of the transition region 26 forming a continuation of the concave face of the dome portion 24 —i.e. the vent side of the disc—as will be detailed below.
[0032] Referring in particular to FIG. 6 , the disc of the invention is formed using an annular anvil or forming tool 34 the lower inner corner of which is chamfered to provide a flat surface 36 extending at an angle θ 1 to the lower surface of the tool 34 . On formation of the disc, the surface 36 defines the linear extent 28 of the transition region 26 , and the score is imparted into the linear extent 28 by means of a hardened score blade 38 dimensioned in accordance with the tool 34 . The linear extent 28 of the disc 20 is supported against the surface 36 of the tool 34 during formation of the score, whereby the score can be accurately located without any damage to or distortion of the disc 20 .
[0033] Once the disc 20 has been scored, a support ring 40 is permanently fixed to the vent side of the disc.
[0034] The disc of the invention is intended to be installed in a suitable bursting disc holder between pipe flanges in conventional manner.
[0035] The disc of the invention is found to have several benefits over conventional products, in particular inversely proportional characteristics whereby the higher the height of the dome portion 24 , the lower the pressure required to effect reversal.
[0036] Referring in particular to FIG. 8 , the arrows A indicate pressure being isentropically applied as a load to the convex face of the dome portion 24 , arrow B indicates the turning moment of the applied load about a fulcrum provided by the corner 30 of the disc, and arrow C indicates the direction of the resultant vectored forces on the disc.
[0037] It will be appreciated that, as the height of the dome portion 24 increases, so does the angle θ 2 (to an approximate maximum of 40°) whereby the direction of the resultant vectored forces as indicated by arrow C is moved in-bound of the support ring 40 and sets up a turning moment indicated by the arrow B about the fulcrum defined by corner 30 .
[0038] There is also an increasing disparity between the strength of the dome portion 24 and the transition region 26 of the disc as the curvature of the dome portion (and consequently the height thereof) increases. The blended nature of the radius 32 prevents a sudden focused failure occurring, in essence diffusing the resultant force vector and preventing a buckle failure about the junction between the transition region 26 and the dome portion 24 .
[0039] The increasing magnitude of the turning moment B about the corner 30 as the height of the dome portion 24 increases (and the strength of the dome portion 24 increases) produces a controllable (linear) repeatable reduction in reverse burst pressure without the need to rely on low dome heights or uncontrollable damage to the dome portion of the disc as has always been necessary heretofore.
[0040] This inversely proportional nature of the disc of the invention will allow the discs to be scored whilst at their lowest dome height (highest burst pressure) and subsequently domed higher (to provide a lower burst pressure), thereby allowing ‘configuration to burst’ of part finished stock.
[0041] Further increases in performance (burst pressure and duty) can be achieved by the inclusion of areas of great rigidity in the dome portion 24 of the disc, thereby focussing all the damage during buckle failure into the scored transition region 26 of the disc. This will result in a more damage-resistant product more capable of handling high duties. For example, a honeycomb-like structure of concave/convex domes of varying heights and dimensions may be provided on the dome portion 24 .
[0042] The preferred value for angle θ 1 is 35°, but this may vary between, for example, 20° and 50°. The height of the dome portion 24 of the disc 20 delivers the tuneable burst pressure of the disc, while the radius 32 between the dome portion 24 and the transition region 26 is a vital part in delivering stable performance and the inversely proportional characteristics. The geometric content of each portion of the disc 20 is a function of the scoring process, free flow area (FFA) requirements and proportionality. Generally speaking, the effective ratio of the transition region 26 to the overall free flow area is 1:4, although ratios between 1:2 and 1:20 can also produce effective results.
[0043] The radius 32 is proportional to the type and gauge of the material of the disc 20 and the nominal bore. Generally speaking the radius needs to be greater than 5 times the thinnest material gauge intended for use on any preform tool.
[0044] Discs according to the invention have the following attributes:
the burst pressure of the formed disc can be left as it is or changed as part of the scoring process, although it is preferred not to change the burst pressure on scoring; the provision of the transition region 26 enables scoring to be effected accurately in a known location whereby a score of reduced magnitude is required, resulting in reduced production time, increased product life, increased yield, easier scoring of difficult materials, more accurate performance and reduced tooling maintenance; controlled variation of inter-relating vectors within the disc allow the production of a wider range of burst pressures from fewer gauges of material using comparatively lower preform energies than heretofore; the design of the product allows for final ‘configure to burst’ features to be tuned in after manufacture by applying further forming energy and/or changing the supporting structure approximately 10 to 20% reduction for the starting burst pressure can be achieved); the nature of the disc allows for a more rigid, damage resistant product than heretofore; the disc of the invention produces lower burst pressures for higher preform energies—true inverse proportionality—thus offering massive benefits, as the previous boundary for a low pressure reverse product was largely driven by the practical limitations of material gauge and low dome portion heights which led to products that either did not open in service or that were scored so heavily that they opened prematurely due to fatigue; the design of the disc 20 and its interaction with the support ring 40 is such that the rest position of the disc once ruptured will allow for a previously unattainable flow performance; as detailed above, the performance of the disc can be enhanced by adding rigidity to the dome portion, for example in the form of a series of hexagon shapes, to create a greater disparity between the area where the score is and where it is not (such an arrangement helps to deliver the objective of putting the score in a location which receives most damage during reversal).
[0053] The provision of the support ring 40 serves a number of functions by:
making the finished product more easily handled; facilitating low energy opening of the product when including teeth; preventing fragmentation of the disc under high energy conditions; providing a means for orienting the disc; providing a means for identifying the product.
[0059] Thus the invention provides a disc which surpasses the previous boundaries for performance of low pressure reverse buckling discs.
[0060] Current materials accepted, the lowest useable pressures for conventional reverse discs are controlled by the ability to provide enough ‘damage’ to the scored area during reverse buckling of the initial dome portion. Various design elements can be included to facilitate a range extension to acquire lower burst pressures, but, in general, it has been the height of the dome portion that has driven the issue to date—the lower the height the lower the burst pressure.
[0061] Recent developments have seen the provision of a single dent to the centre of the dome portion, and in some cases peripheral indentation, in attempts to lower the burst pressure for given dome portion heights and material gauge/type. These efforts result in damaged dome portions which can no longer vector forces efficiently, and use the damaged area as a failure mode or focus to lower the reverse pressure. However such arrangements are still constrained by the issue of the height of the dome portion and providing sufficient damage to the scored area on reversal to tear the score.
[0062] The invention delivers a means whereby the highest dome height (as shown in FIG. 7 a ) delivers the lowest reverse pressure and the lowest dome height (as shown in FIG. 7 b ) delivers the highest reverse pressure. This inverse proportionality is clearly evident from the graph of FIG. 11 in which the abscissa represents the pressure applied to form the dome portion and the ordinate represents the reverse burst pressure. Lines X and Y thereon represent, respectively, traditional scored and unscored discs, while line Z represents a disc according to the invention, either scored or unscored. | A safety pressure relief device comprises an annular flange portion ( 22 ), a concave/convex dome portion ( 24 ) and a transition portion ( 26 ) between the flange portion ( 22 ) and the dome portion ( 24 ), the transition portion ( 26 ) comprising a linear extent ( 28 ) extending from the annular flange portion ( 22 ) at a first acute angle (θ 1 ) to the plane of the flange portion ( 22 ), a tangent to the dome portion ( 24 ) at its junction with the transition portion ( 26 ) making a second acute angle (θ 2 ) with the plane of the flange portion ( 22 ) which is greater than said first angle (θ 1 ), a line of weakness being formed in and around part at least of the linear extent ( 28 ) of the transition portion ( 26 ). | 8 |
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention relates to a method and apparatus for storage and playback of video, audio, multimedia and other data recorded on re-writeable, non-volatile, solid-state storage media.
[0003] 2. Background Art
[0004] In the current environment, when you wish to view a movie that has been released on DVD or Video Cassette, the movie is rented for some period of time from a rental location (Blockbuster™, Hollywood Video™, or similar) at the end of said period of time the DVD or Video Cassette must be returned to the rental location. Alternative rental modalities (MovieBeam™, NetFlix™, or similar) offer either significantly less selection, or the need to receive and return the DVD or Video Cassette back to the rental location via a postal/mail service. The perennial problem for consumers of video rental services is the need to return the DVD or Video Cassette after the prescribed viewing period or incur fines or other penalties, or the fact that alternative rental modalities have significantly lower selections, and do not offer the “browsing” capability offered by a “brick and mortar” rental facility. Some services have attempted to remove the need to return the DVD media by creating “degrading” DVD media which become unreadable and thus unusable after a certain time period. This absolves the user of the need to return the DVD media itself, but adds considerably to the cost of goods for the rental facility, and creates significant waste if these degradable DVD's are utilized to any great degree. Despite the need to return the DVD or Video Cassette, and the possible late fees or other fees associated with renting programs from “brick and mortar” rental facilities, consumers are still attracted to these sites because of the vast selection and the ability to browse not only categories and titles, but the actual packaging of the movies. Brick and mortar facilities have attempted to mitigate the negatives associated with their services by creating “no late fee” policies, but these are still tied to the need to return the DVD or Video Cassette at some point.
SUMMARY OF THE INVENTION
[0005] The present invention comprises a method and apparatus for playback of programs and other works recorded on re-writeable, non-volatile, solid-state storage media. One embodiment of the invention relates to re-writeable, non-volatile, solid-state storage media used to distribute motion pictures and other audio/video data, programs or works. The data stored on said storage media is stored with pre-determined playback criteria, which determines the allowed number of playback sessions, or the time-period where the recorded data remains useable. After the allowed number of playback sessions have been used, or the pre-determined time-period has elapsed, the data set to which the playback criteria is assigned is permanently erased, and the storage media is prepared to receive new data sets during the next visit to the rental facility or internet rental site.
[0006] For example, a “key-drive” form-factor utilizing re-writeable, non-volatile, solid-state storage media, and a corresponding “set-top-box” playback device would be provided to the consumer at the rental facility. At some future point, it is envisioned that the interface for the storage device would be integrated into the actual television set or other viewing device. This “key-drive” would then be loaded with the consumer's choice of programs, and the playback criteria set to the number of viewings or the time-period for viewing the consumer desires for each program. The consumer returns home and is able to view the programs according to the pre-determined playback criteria, after which the media erases itself and is ready to load new programs from the rental facility at the consumer's convenience.
[0007] In one embodiment of the invention, the consumer would choose several movies, and could assign the same playback criteria to all of the movies, or could assign each movie a separate set of playback criteria. After setting these playback criteria and paying the rental fees the consumer can leave with the “key-drive”. After arriving at their home or other viewing location, the consumer places the “key-drive” into the interface of the “set-top-box” and can then view each program as desired according to the playback criteria.
[0008] In one embodiment of the invention, the consumer may choose to utilize an “online” service wherein the consumer would download programs from the internet and load them through their computer onto the “key-drive”. The “online” service would provide the same functionality of setting playback criteria, and paying for the rental, but would also offer the option to pay for and modify already set playback criteria for any of the programs already loaded onto the “key-drive”.
BRIEF DESCRIPTION OF THE FIGURES
[0009] FIG. 1 is a block diagram of a video viewing component system that can be used with an embodiment of the invention.
[0010] FIG. 2 is a block diagram of a computer system that can be used with an embodiment of the invention.
[0011] FIG. 3 is a graphical representation of a re-writeable, non-volatile, solid-state storage medium on which media content data files are recorded in accordance with an embodiment of the invention.
[0012] FIG. 4 is a flow chart of a method that may be used to store media content as data files onto re-writeable, non-volatile, solid-state storage medium of FIG. 3 for playback in an embodiment of the invention.
[0013] FIG. 5 is a flow chart of a method that may be used to playback the media content stored as data files on storage medium of FIG. 3 .
[0014] FIG. 6 is a flow chart of a method that may be used to modify playback criteria for media content stored as data files on storage medium of FIG. 3 .
DETAILED DESCRIPTION OF THE INVENTION
[0015] A method and apparatus for storage and playback of programs recorded on re-writeable, non-volatile, solid-state storage media is described. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the invention. It will be apparent, however, to one skilled in the art, that the invention may be practiced without these specific details. In other instances, well-known features have not been described in detail in order not to obscure the invention.
[0016] The invention can be implemented using any type of re-writeable, non-volatile, solid-state storage media. Examples include, without limitation, flash memory, nano-film based memory, memory sticks of various types, RAM cards, and other specific and non-specific re-writeable, non-volatile, solid-state storage media.
[0017] One embodiment uses a memory stick (or Flash Drive) as the re-writeable, non-volatile, solid-state storage media. In this embodiment, the re-writeable, non-volatile, solid-state storage media contains one or more program files, such as motion pictures, musical performances, and a plurality of secondary programs, such as movie trailers and product advertisements. The invention is, however, equally applicable to other types of primary and secondary programs, including musical recordings, computer software (including computer games, simulations and virtual environments), video recordings, multi-media programs, etc.
[0018] FIG. 1 shows an example of apparatus that may be used to playback media content stored as data files recorded on a re-writeable, non-volatile, solid-state storage media in one embodiment of the invention. The apparatus of FIG. 1 includes a re-writeable, non-volatile, solid-state storage media (such as a memory stick, “Flash Drive”, or other) component 100 which is inserted into a playback device 140 , which is in-turn connected to a receiver and/or video monitor 120 and, in this embodiment of the invention, a sound system 110 is connected. The playback device 140 is as described in 29 below, and provides a video signal output and any corresponding sound output, or simply a sound output in the case of audio only recordings, and subsequently displaying it on video monitor 120 . Monitor 120 is any kind of display monitor that can display the video signal received from playback device 140 . Monitor 120 may, for example, comprise a cathode ray tube monitor, a projection monitor, a gas plasma monitor, an LCD monitor, etc. Sound system 110 is any kind of sound amplifier and speaker system capable of reproducing an audio signal output by playback device component 140 . Sound system 110 may, for example, comprise a stereo amplifier and speaker system, and may include features such as, for example, Dolby™ surround sound compatibility. Monitor 120 and sound system 110 may comprise separate components or may be integrated into one or more combined units. Control of playback device 140 may be controlled via a remote control device 130 specific to playback device 140 , or a remote control device 130 compatible with any or all of the components 110 , 120 , and/or other components not mentioned, but capable of being controlled via such remote control device 130 .
[0019] FIG. 2 shows a computer system that may be used to playback media content stored as data files recorded on a re-writeable, non-volatile, solid-state storage media in one embodiment of the invention. The computer system shown in FIG. 2 includes a CPU unit 150 that includes a central processor, main memory, peripheral interfaces, input-output devices, power supply, and associated circuitry and devices; a display device 170 which may be a cathode ray tube display, LCD display, gas-plasma display, or any other computer display; a keyboard input device 190 , and/or a secondary input device 180 which may include a mouse, digitizer, or other input device; and a playback device 140 for retrieving data stored on a re-writeable, non-volatile, solid-state storage media 100 . The computer system may or may not include non-volatile storage, which may include magnetic, optical, or other mass storage devices, and a printer 195 . The computer system may also include a network interface 185 , which may include a modem, allowing the computer system to communicate with other systems over a communications network such as the Internet. Any of a variety of other configurations of computer systems may also be used.
[0020] FIG. 3 is a graphical representation a re-writeable, non-volatile, solid-state storage medium. The re-writeable, non-volatile, solid-state storage medium shown in FIG. 3 may comprise a memory stick, “Flash Drive” or any other suitable re-writeable, non-volatile, solid-state storage media.
[0021] In FIG. 3 , storage medium 100 includes one or more re-writeable, non-volatile, solid-state storage medium (a memory “chip”) 200 , a processor 210 for executing computer processor readable program code embodied and stored on the memory chip 200 , and support chipset and electronics 205 which support the execution of said computer processor readable program code. File system information which contains information about the file system structure used to store data on memory chip 200 may also be stored on memory chip 200 using any number of partitioning technologies, known to those skilled in the art, or may be stored on an alternative memory chip collocated with memory chip 200 , or as part of the support chipset and electronics 205 . File system information area may also contain directory information indicating the identity and storage location of programs stored on memory chip 200 . Playback criteria and user account information may likewise be stored on memory chip 200 or stored on an alternative memory chip collocated with memory chip 200 , or as part of the support chipset and electronics 205 .
[0022] FIG. 4 is a flow chart of a method that may be used to store media content data files on storage medium 100 of FIG. 1 . In this embodiment, media content is stored as one or more data files on the memory chip 200 and linked to playback criteria set at the time of initial storage on memory chip 200 or on support chips 205 , or to playback criteria modified after the time of initial storage on memory chip 200 or on support chips 205 . Playback criteria may remain stored on memory chip 200 , or on support chips 205 and act as “default” playback criteria in the absence of newer playback criteria, thus retaining the user's preferential playback criteria through multiple storing and deletion cycles. The method of storing media content data files may be controlled and implemented by the user, a store clerk, or by some other means of either manual or automated processes known to those skilled in the art. In this embodiment, the user may provide the storage medium 100 to the media rental clerk with a selection of desired media programs, and the clerk will load the desired media content data files onto the storage medium 100 and apply playback criteria to each file as per the user's instructions, or as per default store policy, or may simply default to existing playback criteria previously stored on storage medium 100 .
[0023] According to the method of FIG. 4 , the storage process begins with a storage library of any number of media content data files stored at 235 , where all video, audio, or other media content data files are stored on a referenced database, or in any of a multitude of data storage systems known to those skilled in the art. Data transfer from the data storage system 235 to the storage medium 100 is initiated by instructions input at input device 240 , which device may be a data-entry terminal, desktop computer, cash register terminal, or any other input device either specifically designed for such function, or modified through attachment, integration, or some other method to function as said input device. Each instruction for a transfer of data from storage system 235 to storage medium 100 is authorized, and payment transacted by reference to the payment account system 250 . Payment account system 250 applies charges as per pre-established pricing structures, which are set by the rental service to each program data set transferred from storage system 235 to storage medium 100 and may consist of any pricing structure conceived and deemed satisfactory by the proprietors of the establishment utilizing the invention as a part of their service, and said payment account system may be an existing account system integrated into this system by an Application Programming Interface (API), or by some other method, or may be an account system designed specifically for this system. After account system correlation, playback criteria is assigned to each media content data file as per the protocol described above in FIG. 4 and is linked independently to each media content data file selected for transfer to storage medium 100 . Prior to media content data file's storage on storage medium 100 , media content data is encrypted and prepared for transport by a data encryption system 260 . This encryption system may exist on the rental facility's computer system, register terminals, on an independent encryption device attached to, or independent of any other system, or any other system known to those skilled in the art to affect the encryption of the data, rendering it unusable outside of the scope of this invention. After encryption at data encryption system 260 the data is recorded to storage medium 100 and is ready for viewing at a remote location via playback device 140 , and a viewing system similar to that described in FIG. 1 , and/or FIG. 2 . Those skilled in the art will recognize that myriad playback systems may be utilized that are substantially different that those described in FIG. 1 , and/or FIG. 2 , but that are still within the scope of this invention.
[0024] FIG. 5 shows a flow chart of a method that may be used to playback programs stored as data files on storage medium 100 of FIG. 3 . In this embodiment of the invention, media content such as video programs, audio programs, or other proprietary or non-proprietary media content stored as data files on storage medium 100 are caused to be played back on a media content viewing component system similar to that described in FIG. 1 , using playback device 140 .
[0025] In this embodiment of the invention, storage medium 100 is placed in the receptacle provided on playback device 140 , which causes playback device 140 to attempt to recognize storage medium 100 as an authorized and compatible device. Upon recognition of storage medium 100 as an authorized and compatible device, computer programmable logic resident on playback device 140 seeks and identifies media content program data files contained on storage medium 100 . If no such files are recognized, playback device 140 sends a video signal to the viewing system as described in FIG. 1 , and/or FIG. 2 displaying text indicating no data files found. If files are found, the files are prepared for de-encryption by de-encryption computer programmable logic corresponding to encryption provided by encryption and transport system 260 , also resident in playback device 140 . Computer programmable logic resident on playback device 140 confirms the status of the playback criteria, and, if any data files have expired their playback date or their number of viewing sessions allocated by the playback criteria, said logic triggers the deletion of said files from storage medium 100 . Playback device 140 sends a video signal to the viewing system indicating the selection of data files available for viewing, and provides a graphical user interface displayed on the viewing system for navigation and selection of data files for viewing utilizing the remote control device 130 . Upon selection of a file for viewing, playback device commences playback of the selected file, and offers myriad options for viewing, similar in substance to all viewing options available through other, standard viewing system available today. Such options may include, but are not limited to fast forward, slow play, rewind, fast rewind, stop, pause, menu of selections, etc. Those skilled in the art will recognize that any number of menu control options for viewing may or may not be included in the viewing options for any given embodiment of the invention.
[0026] FIG. 6 shows a flow chart of a method that may be used to modify playback criteria for data-files recorded on storage medium 100 of FIG. 3 . In this embodiment of the invention, playback criteria linked to media content data files stored on storage medium 100 is modified to allow an extension of the time allocated for viewing, or increase the number of viewing sessions allowed for said media content data files, and payment for said extension of time allocated for viewing or increase in number of viewing sessions is made.
[0027] In this embodiment of the invention, storage medium 100 is inserted into input device 240 as described in FIG. 4 . In addition to the input device 240 described in FIG. 4 , those skilled in the art will recognize that a personal computer with internet connectivity could serve as input device 240 provided a computer processor readable program is provided the user to affect the use of said personal computer as an input device. Upon insertion of storage medium 100 into input device 240 , computer processor readable program code initiates a verification of status of all media content files and associated playback criteria stored on storage medium 100 , correlates said status with the user's account on payment account system 250 , and presents the user with a Graphic User Interface (GUI) which provides a menu of options, including, but not limited to account status, status of media content data files stored on storage medium 100 , and an option to extend the time or number of viewing sessions for any or all of the media content data files stored on storage medium 100 . If the user elects to increase the allocated viewing time, or increase the number of viewing sessions, the system modifies payment account 250 accordingly and debits the user account according to the pre-determined payment structure. Those skilled in the art will recognize that any number of variations exist for modification of both the account status and the media content file status through this embodiment of the invention, including adding and subtracting media content files from storage medium 100 , debiting or crediting the user account, or any number of other modifications.
[0028] Thus, a method and apparatus for time/date and/or session-limited storage and playback of proprietary and non-proprietary media content utilizing re-writeable non-volatile memory. Although the invention has been described with respect to certain example embodiments, it will be apparent to those skilled in the art that the present invention is not limited to these specific embodiments. Further, although the operation of certain embodiments has been described in detail using certain detailed process steps, some of the steps may be omitted, the steps may be performed in different sequences, or other similar steps may be substituted without departing from the scope of the invention. Other embodiments incorporating the inventive features of the invention will be apparent to those skilled in the art. | The present invention comprises a method and apparatus for temporary storage and playback of proprietary and non-proprietary media content and other works temporarily recorded on a re-writeable, non-volatile solid-state memory device. One embodiment of the invention relates to media such as motion pictures and other audio/video programs or works. The invention involves a manner of utilizing re-writeable, non-volatile, solid-state storage media (such as Flash memory), including but not limited to a USB-memory key or similar device, to transfer proprietary and non-proprietary content such as the above referenced motion picture and other audio/video programs or works, from a distribution source such as a video rental facility, to the re-writeable, non-volatile, solid-state storage media, and then to a user's viewing location (home, office, or other remote location), and allowing viewing of said content through a set-top box or other specifically designed playback device for a limited period of time, at the expiration of which time the re-writeable storage device automatically and permanently erases the recorded content leaving the storage device ready to receive and again temporarily store and playback new content. Because of the increasingly large capacity of non-volatile memory to store content, the content provider/rental facility can allow for storage of any number of motion picture and other audio/video programs, and said provider/rental facility can set varying expirations for each of the stored motion picture and other audio/video programs. | 7 |
TECHNICAL FIELD
This invention relates generally to a liquid crystal display (LCD) device, and more particularly to a nematic LCD device having a storage effect.
This invention is related to commonly assigned, copending U.S. patent application Ser. No. 381,281 by K.-H. Yang filed May 24, 1982 entitled "Weak Boundary Storage Liquid Crystal Display Devices".
BACKGROUND ART
Conventional direct-view field effect liquid crystal display (LCD) devices, such as twisted nematic (TN) displays and guest-host (GH) displays having dichroic dyes as the guest material in nematic or cholesteric hosts, are known. These conventional LCD devices have limited multiplex capacity because of a high V on /V th ratio, where V on and V th are the root-mean-square voltages for the device to be turned on and when the device is at threshold voltage, respectively. Furthermore, conventional nematic LCD devices have no storage effect, so that direct pel (picture element) drive or refresh circuits are necessary for their operation. For these reasons, in general, conventional nematic LCD devices are suitable only in display applications of the low information content type, such as digital watch displays.
To achieve greater versatility field effect LCD cells, such as the TN type, have been constructed. In such cells a liquid crystal material having a positive dielectric anisotropy is interposed between a pair of (upper and lower) parallel glass substrates, with the molecules of the LC material paralleled with the upper and lower substrates and twisted 90° therebetween. Such an LCD cell is disposed between a pair of polarizers with polarizing axes intersecting with each other at right angles. With this typical construction, light impinging upon the device is first polarized linearly by one of the polarizers. Then its polarized plane is rotated 90° by the liquid crystal molecules in a twisted arrangement and finally light transmits through the other polarizer. Where transparent electrodes formed with a pattern of a letter, digits, or other symbols are disposed on the inner surfaces of the upper and lower substrates, and are impressed with a voltage greater than the threshold voltage of the device, the LC (Liquid Crystal) molecules will be arranged in substantially the vertical direction or in the direction of the field. Under these conditions, the polarized plane of incident light will be intercepted by the analyzer. Thus the pattern can be displayed by controlling the direction of the LC medium within the LC cell to yield a transmission and an interception of the light.
Smectic liquid crystal display devices having a storage effect also known. This type of LCD device provides an indefinite storage of the information in the form of scattering regions in an otherwise clear background. More specifically, information is recorded by an intensity modulated laser beam which heats the LC material locally to create light-scattering centers. For more details see, for instance, "Laser-Addressed Liquid Crystal Projection Displays", by A. G. Dewey et al, pp. 1-7, Proceeding of the S.I.D., Vol. 19/1 (1978).
Optical storage effects in mixtures of nematic and cholesteric materials with negative dielectric anisotropy were observed and reported by Heilmeier and Goldmacher, Proceedings IEEE 57, 34 (1969). According to Heilmeier et al, a sample with no applied voltage was initially in a relatively clear state. The application of a DC or a low frequency AC voltage of a sufficient magnitude induced an intense scattering known as dynamic scattering. When the voltage was removed, the dynamic scattering disapppeared, but a quasi-permanent forward scattering stage remained. The storage decay time was reported to be on the order of hours. Furthermore, the scattering state could be erased and returned to the clear state by the application of an audio frequency signal.
The effects of weak boundary coupling on liquid crystal display performance is reported in an article by J. Nehring et al entitled, "Analysis of Weak-Boundary-Coupling Effects in Liquid-Crystal Displays" J. of Applied Physics 47, 850 (1976). According to the article, the multiplexing capacity of LCD devices can be improved by controlling the liquid crystal material-to-substrate anisotropy.
Heretofore several types of surface treatment techniques have been employed and applied in the making of liquid crystal display devices. For instance, in U.S. Pat. No. 4,140,371 entitled, "Liquid Crystal Display Devices", and issued to M. Kanazaki et al, an LCD device is described in which liquid crystals are oriented slightly inclined by the use of an orientation controlling structure formed by rubbing or oblique vapor deposition.
In order to control the alignment of the molecules of a liquid crystal material, some prior LCD devices employ surfactant coatings. For instance, in U.S. Pat. No. 3,967,883 entitled, "Liquid Crystal Devices of the Surface Aligned Type", and issued to D. Meyerhofer et al, it is described that one or more inside surfaces of an LCD device enclosure is coated with successive, slant-evaporated layers for the purpose of controlling the alignment of the molecules of the liquid crystal material.
Another prior LCD device employing the surface rubbing technique is described in U.S. Pat. No. 4,083,099 entitled, "Manufacture of a Twisted Nematic Field Effect Mode Liquid Crystal Display Cell", and issued to K. Yano et al. According to the patent, the surface of the transparent insulating film of the LCD device is rubbed to form micro-grooves aligned in a predetermined direction. The two glass substrates of the LCD device carry these transparent insulating films having micro-grooves formed using this rubbing technique. In addition, the application of this rubbing technique to promote the uniformity of the LCD optical effect is also mentioned and appreciated by M. Biermann, et al, in U.S. Pat. No. 3,892,471 entitled, "Electrodes for Liquid Crystal Components".
The effects of surface treatment on the liquid crystal material-to-substrate anisotropy is described in an article entitled, "Anisotropic Interactions Between MBBA and Surface-Treated Substrates", by S. Naemura, pp. C3-514-518, Journal De Physique, Colloque C3, supplement au no. 4, Tome 40. The article reported the measurements of the easy axis and anchoring strength coefficient between MBBA and substrates with various surfactants layers.
U.S. Pat. No. 4,028,692 of Ngo for "Liquid Crystal Display Device" requires no refresh because storage is provided.
U.S. Pat. No. 4,228,449 of Braatz for "Semiconductor Diode Array Liquid Crystal Device" describes an LC device incorporating semiconductor diodes with a storage mode.
U.S. Pat. No. 3,936,816 of Murata et al for "Flat Display System" shows a display system with row electrodes and column electrodes. The display elements can be LC devices, but no memory effect is described.
It will be seen from a careful consideration of all the foregoing art that there exists a need for an improved direct-view, high information content LCD device having convenient addressability along with an inherent storage effect.
SUMMARY OF THE INVENTION
It is a principal object of this invention to provide an improved direct-view, high information content nematic liquid crystal display (LCD) device.
It is a further object of this invention to provide a four-terminal LCD cell having convenient addressability combined with an inherent storage effect.
It is another object of the present invention to provide a low voltage, low power LCD cell having no requirement for refresh circuitry for its proper operation.
It is also an object of the present invention to provide a storage effect twisted nematic (TN) LCD cell.
It is still another object of the present invention to provide a storage effect nematic homogeneous LCD cell.
A four terminal liquid crystal display device in accordance with the invention includes two sets of orthogonally related row and column electrodes separated by dielectric on their respective surfaces above and below the interposed liquid crystal medium. The electrodes in proximity to the LC medium are the column electrodes which are foraminated or have microapertures therethrough which permit the electric field established between the row and the column electrodes in each set to extend through the microapertures into the LC medium to establish a fringe electric field normal to the surface of the column electrodes tending to retain the LC directors in the vertical position. This permits the application of low voltages to the electrodes and thereby increases the life of the LC media which are otherwise degraded by high voltages.
In accordance with this invention, the liquid crystal display device includes at least one cell having a memory effect comprising:
first and second parallel arrays of column electrodes;
a liquid crystal material contained between the first and second arrays of column electrodes,
first and second parallel arrays of row electrodes respectively disposed outwardly of the extending orthogonally to the first and second arrays of column electrodes;
the fifrst array of column electrodes being isolated from the first array of row electrodes by a first thin dielectric layer;
the second array of column electrodes being isolated from the second array of row electrodes by a second thin dielectric layer;
a pair of parallel housing plates and means for sealing the plates together for containing the row and column electrodes and the liquid crystal material with at least one of the plates being optically transparent; wherein the column electrodes are electrically porous such that when potentials are applied to the row and column electrodes fringe fields may be produced in the boundary layers of the liquid crystal material to overcome the anisotropic surface anchoring force
whereby the memory effect is achieved by these fringe fields when appropriate potentials are applied to the row and column electrodes.
A typical display device comprises an array of the liquid crystal display cells, with these column electrodes composed of a porous material.
Preferably the column electrodes may each be composed of a foraminated structure, and more particularly, it is desirable that the foraminated structure comprise conducting grids with nonconducting voids. Alternatively, the column electrodes may each be composed of a segmented structure, which preferably comprises a set of fine parallel conducting stripes.
In any event, it is desirable that the column electrodes have surfaces with mechanical characteristics enhancing the wall surface anchoring force applied to the liquid crystal material anisotropically.
Therefore, the surface of each column electrode in the first and second arrays of the column electrodes preferably comprises a matrix of apertures in the form of micropores therethrough.
The foregoing and other objects, features and advantages of this invention will be apparent from the following more particular description of the best mode for carrying out the invention, as illustrated in the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
The details of the invention will be described in connection with the accompanying drawings, in which:
FIG. 1 is a plot of θ(x) as a function of x/ξ m for both the relationship between the electric field force which acts upon liquid crystals on the surface of an electrode and the anisotropic surface anchoring force acting on the liquid crystals. The lower curve is that for an isotropic liquid crystal to surface anchoring force.
FIG. 2 is a schematic diagram of a display cell with liquid crystal directors shown parallel to the walls of the display cell.
FIG. 3 is a schematic diagram of a four terminal display device in accordance with this invention.
FIG. 4 is a diagram of the row and column lines for the first and second pel positions of a cell, with the voltages applied indicated on the lines for the two pels.
FIG. 5 is a graph of intensity vs voltage for both homogeneous and homeotropic boundary conditions (BC) with the threshold voltage shown, for a cholesteric dye system.
FIG. 6 is a similar graph to FIG. 5 showing the effects of employing a 90 degree twist homogeneous boundary condition on the cholesteric dye system.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Conventional liquid crystal devices (LCD) operated by electric field switching which provide a direct view of the liquid crystals have limited multiplex capability. The limitation in multiplex capability is caused by the large ratio of the RMS turn on voltage (V on ) to the threshold voltage (V th ) where V on /V th is greater than or equal to 1.25. Such conventional LCD devices include twisted nematic (TN), dichroic dyes in guest-host/nematic (GH-N), or in guest-host/cholesteric (GH-C) liquid crystal media.
As a result such conventional LCD's with their large V on /V th ratios are suitable for use only for the display of images with low information content applications such as digital watches. It is too expensive to employ these LCD's for the display of information content greater than two lines of about two hundred characters because of the limited multiplex addressing capability. [See Alt and Pleshko, IEEE Trans. Elec. Dev. E.D.-21, 990 (1973)]. Furthermore, such LCD's are inadequate because they include no memory capacity so that direct pel drive or refresh circuits for refreshing the signals to the display are necessary for their operation.
This invention relates to a new type of LCD display which incorporates a memory effect retaining the displayed data for a predetermined time. This is particularly useful for directly viewable high information content displays. We have named these display devices Fringe Field Switching Liquid Crystal Displays (FFSLCD). These FFSLCD devices operate based on the fringe-field switching of an LC boundary layer adhering to the wall of the LC cell in addition to the bulk switching of conventional LCD devices.
In accordance with this invention the LC medium contacts a wall along the x-axis from x=0 to x approaching infinity. The layer of molecules of LC medium in contact with the wall is strongly anchored to the wall surface anisotropically with LC directors comprising local unit vectors indicating the average direction of orientation of the LC molecules along their lengths parallel to the surface of the wall (FIG. 2). If a uniform electric field E is applied to the LC medium along its x-axis in the position direction where
0<ε.sub.a /ε.sub.11 <<1
where ε a and ε 11 are the LC dielectric anisotropy and the LC dielectric constant parallel to the director, respectively, by solving the elastic deformation equation in one dimension which follows:
(1/ξ.sub.m).sup.2 (d.sup.2 θ(x)/dx.sup.2)-sin θ(x) Cos θ(x)≡0
or ##EQU1##
θ(x)=2 tan.sup.-1 [exp (-x/ξ.sub.m)]x≧0 (1)
where ##EQU2## K is the LC splay elastic constant, and θ(x) is the angular orientation of an LC director as a function of x (θ=0 is parallel to x-axis). If the LC-to-wall surface anchoring is isotropic, then the solution will be
θ(x)=0 for x≧0 (2)
FIG. 1 depicts the results of Eqs (1) and (2). In the first case [Eq. (1)], the LC is subjected to two forces, a force due to the electric field and an anisotropic surface anchoring force. The balancing of the two forces creates strain in the LC medium. The strain energy per unit area in the LC medium can be calculated as ##EQU3##
In the solution of Eq. (2), there is no strain energy deposit in the LC medium because there is no anisotropic surface anchoring force to balance the force due to the electric field so that the LC directors are aligned parallel to the electric field to minimize the free energy. The free energy difference per unit area between Strong Anisotropic Surface Anchoring (SASA) (Eq. (1)) and Isotropic Surface Anchoring (ISA) (Eq. (2)) is ##EQU4##
If F/A is greater than the strong anisotropic surface anchoring (SASA) energy Fa s (i.e., the electric field is strong enough to overcome the SASA force) the molecules in the LC layer adjacent to the wall surface will flip their director orientation from parallel (as shown in FIG. 2) to perpendicular to the surfaces of the walls of plates 12 and 13. The director orientation equation is switched from Eq. (1) to Eq. (2). Typical anisotropic surface anchoring energy ranges from 1 erg/cm 2 to 10 -3 erg/cm 2 , [sec E. Guyon and W. Urbach in "Nonemissive Electrooptic Displays" edited by A. R. Kmetz and F. K. Von Willisen, P121, Plenum Press (1976)]. If we assume Fa s =1 erg/cm 2 , the SASA condition, the corresponding electric field required to flip the orientation of the directors, of the boundary LC layer is E c ≅0.75×10 6 V/cm.
In the SASA case, if we apply E<E c =0.75×10 6 V/cm on the LC medium first to align the LC molecules as described by Eq. (1) and later remove the applied electric field, the LC molecules will relax back to the case where their LC directors are aligned parallel to the wall surface to release the strain energy. Now, consider an SASA case in which one applies an electric field E m <E c to the LC medium first. Eq. (2) will describe the LC director orientation with corresponding constant ξ m .
Then, a strong surface electric field impulse E s i >E c parallel to E m is applied on the LC molecule layer adjacent to the wall surface to overcome the SASA energy of the wall. The θ(x) will flip from Eq. (1) to Eq. (2) and will maintain this state after the surface electric field impulse is removed if
E.sub.m ≧E.sub.c sin.sup.2 φ≅0.2 E.sub.c (5)
Equation (5) is derived based on the assumption that [Rapini and Papoular J. Phys. (Paris) 30 C4-54, (1969)]:
Fa.sub.s =W. sin.sup.2 θ(x=0) (6)
and
P=1/2<3 cos.sup.2 φ-1> (7)
where P is the order parameter of the nematic LC molecules and P=0.72 [W. Maier and A. Saupe, Z. Naturfor Schg. 14a 882 (1959) and 15a 287 (1960)] at room temperature and TnT=100° C. After E s i is removed, the LC layer molecules adjacent to the wall surface have a tendency to restore their LC directors back parallel to the wall due to the thermal fluctuation of the LC director orientation. But this tendency is reduced due to the LC long range interaction force which tends to keep the LC directors uniformly aligned along the x-axis. The electric field E m has to be greater or equal to 0.2 E c to enforce the directors to align along the x-axis.
Now consider the case of FIG. 2 in which a nematic LC medium is confined within the space between two conducting-film coated glass plates separated by distance d (cell spacing). The LC directors 10 in the cell 9 in FIG. 2 are aligned parallel to the glass plate walls 12 and 13 (coated with conducting films 14 and 15) under homogeneous boundary condition due to the SASA force described by Eq. (6). FIG. 2 depicts this situation. The deformation of LC directors in the cell by an externally applied electric field has been solved by Rapini and Papoular, supra. There exists a threshold electric field E th , below which no deformation occurs, and above which the deformation of the LC director orientation starts at the middle of the cell and propagates toward the wall as the applied field increases further beyond ##EQU5##
In the SASA case, biasing the cell 9 with an uniform electric field E such that 0.5×E th .sup.(s) <E<E th .sup.(s), the LC is in a quiescent state. If a surface electric field impulse greater than E c ≃0.75×10 6 V/cm is applied to both the wall surfaces and flips the LC directors 11 adjacent to the walls 12 and 13 into the perpendicular direction, the LC directors 10 throughout the cell 9 will align parallel to E. The LC directors 10 will remain in this activated state and have a memory effect after the surface field impulse is removed. When E is removed, the LC directors 10 in the cell 9 will relax back to the original homogeneous orientation.
In a twisted nematic LC cell with SASA boundary conditions the formula to calculate the threshold field is similar to Eq. (8) except that it takes a different value of elastic constant.
The conventional LCDs including TN, GH-N and GH-C have a common cell structure. The cell is a two-terminal device in the sense that the LC is sandwiched between two electrodes which are fabricated on two pieces of glass serving as the LC container. The FFSLCD cell 19 of this invention is a four-terminal device and its schematic is shown in FIG. 3. The LC containing cell 19 is composed of two pieces of glass 22 and 23 on which arrays of stripes of row electrodes 24 and 25 are evaporated. The width of each row electrode 24, 25 is from 0.127 mm to 2.5 mm depending on the display resolution chosen. The upper array of row electrodes 24 is transparent to visible light and the lower row electrodes 25 can be transparent (for TN configuration) or reflective (for GH-N or GH-C configurations). Upon each of those arrays of row electrodes 24, 25 are fabricated a set of uniform transparent dielectric layers 26, 27 with thickness ranges from a few hundred angstroms to a few micrometers. Arrays of transparent column electrodes 28, 29 are then deposited on top of the respective dielectric layers 26, 27. The width of each column electrode 28 and 29 is similar to that of the row electrodes 24, 25. Each column electrode 28, 29 is not a piece of uniform conducting film. It consists of either a segmented structure of parallel fine conducting stripes (width<few microns) or a foraminated (mesh-like) structure (with small pores or perforations, extending completely through the column electrodes to permit the fringe electric fields to extend through the surfaces of the column electrodes into the LC media, on the order of 0.2 μm to 5. μm in size) such as conducting grids with square, circular or hexagonal non-conducting voids 30. The LC liquid is filled in between the segmented or foraminated column electrodes. There are several ways to apply the voltage waveform to operate the device. The following is an example. Assume a TN LC configuration with homogeneous boundary condition and the SASA case. The foraminated column electrodes are connected to signal drivers which output square wave AC voltage such that, when +V o appears on the top column electrode 28, then -V o appears on the corresponding bottom column electrode 29 and vice versa. The non-strobing top and bottom row electrodes 24, 25 are at zero voltage. The magnitude of V o is selected according to two criteria. It is (1) below the threshold voltage of the LC cell and (2) its fringe field, leaking through the non-conducting voids 30 in column electrodes 28, 29, and the dielectric layers 26, 27 to the adjacent row electrodes, is less than E c =0.75×10 6 V/cm so that the fringe field is not large enough to flip the boundary LC layer from the homogeneous to homeotropic condition. Regarding the first criterion, one can also change the E th .sup.(s) (or threshold voltage) of a TN cell according to Eq. (8) by tailoring the LC material with a different ε a . In the strobing row electrodes 24, 25, a single square wave with magnitude 2 V o is applied on the top row electrode 24 and -2 V o on the bottom row electrode 25. For simplicity, two rows and two columns of the crossed arrays are shown in FIG. 4 as disposed on the surface of the top glass 22. The voltage waveform is shown for the top row 24 and the top column electrodes 28 only. By symmetry, the corresponding voltage waveforms on the bottom row and the bottom column electrodes 25, 29 have the reverse polarity. The pel #1 represents the selected pel and is turned on and remains on after the strobe pulse. The requirement of the 2 V o magnitude is to satisfy the condition that, when the voltage drop between the top row and column electrodes 24, 28 at the turned-on pel is 3 V o , most of the fringe field at that pel, appearing on the surface of the foraminated column electrode 28, is greater than E c ˜0.75×10 6 V/cm to flip the boundary LC layer from homogeneous into homestropic condition. Due to this flip, the threshold voltage across #1 pel is suddenly lowered to a value less than |2 V o | so that this pel is turned on and remains on. The pel #2 represents a non-selected element. At this pel position, the corresponding voltage is V o whose fringe field is below E c so that this pel cannot be turned on since the LC directors of the boundary LC layer are not flipped to lower the threshold field across the LC sample. Detailed dimensions on ds (dielectric thickness), d (cell spacing: spacing between column electrode arrays), L (dimension of voids or holes 30 on a mesh-type conducting column electrode), and W (the width of conducting-mesh lines on a mesh-type conducting column electrode), as shown in FIG. 3, can be calculated and fabricated when different LC material and surface anchoring methods are chosen.
The cell structure as shown in FIG. 3 is also suitable using GH-N and GH-C configurations. The LC-to-surface anchoring condition can also be adjusted. The corresponding dimensions of the cell structure and the voltage waveform can also be selected for their operations.
Combining the structure of the top or bottom substrate as shown in FIG. 3 with a conventional piece of conducting-film coated glass to form an LC cell with, respectively, different surface anchoring treatments for each substrate is also comprehended by this invention. In this case, the flipping of a single LC director boundary layer is enough for the operation of the FFSLCD.
Above, the basic concept, the device fabrication and the operation of FFSLCD (Fringe Field Switching Liquid Crystal Displays) are described. This section describes methods for improving the storage time and contrast ratio of FFSLCD using dichroic dyes in cholesteric LC as the display medium. The name of the fringe-field-switched storage dichroic dyes in cholesteric liquid crystal display will be abbreviated as FFSGH-C. The conventional dichroic dyes in cholesteric LC display will be abbreviated as the W-T cell. The light transmission of a transmitting W-T cell as a function of the applied root-mean-square voltage is sketched in FIG. 5 for both homeotropic perpendicular and homogeneous (parallel) boundary conditions. As shown in FIG. 5, there exists a threshold voltage ##EQU6## for both boundary conditions, where P, K 2 , and ε a are the pitch, the twist elastic constant, and the dielectric anisotropy of the cholesteric LC, respectively. The cell spacing is denoted by d. Eq. (9) is derived without reference to the boundary conditions. However, when the applied voltage exceeds V th , the increase in the light transmission for the case of the homogeneous boundary condition is much slower than that of the homeotropic boundary condition. This is expected because the homogeneous boundary condition adds hindrance for the LC to align parallel to the electric field.
Now assume a FFSGH-C with the homogeneous boundary condition using a line-at-a-time, three-to-one, matrix addressing scheme. The column drivers deliver a root-mean-square voltage V o on each quiescent LC pel at the beginning. If V o =V th , the selected pel on the strobing row has 3 V o across its electrodes.
This pel is turned on during the strobe pulse. After the strobe pulse, the transmission of this on-pel will be shown as point #1 on the solid curve of FIG. 5. (In operating the FFSGH-C, the boundary condition is changed from the homogeneous to the homeotropic by the fringe field). This point is on the hysteresis loop of the solid curve. It represents a meta-stable state and is transformed into the scattering focal-conic state by the gradual generation of nucleation centers within the LC or from the boundary. The life time of this state is difficult to predict, control, and reproduce. The same argument holds if V o lies within the range shown as V th to V 1 in FIG. 5.
If V o assumes a value greater than V 1 , the storage effect of the turned-on pel is improved with the trade-off of degrading the contrast ratio. In order to improve both the storage time and the contrast ratio of FFSGH-C, we can shift the dashed curve as shown in FIG. 5 to a higher voltage region as shown in FIG. 6. This can be done by imposing a 90° twist homogeneous boundary condition on the cholesteric dye system such that the imposed twist is in the same direction as the natural cholesteric helix. V o can take a value in the region shown as the shaded area in FIG. 6 to improve both the contrast ratio and the storage time of FFSGH-C.
The value of τ in FIG. 4 is within the range of 5-50 milliseconds. The frequency of the column voltage should be in the range from 10 Hz to 100 Hz. More importantly Δt as shown for the column voltage transition from low to high (vice versa) must be shorter than about 2 milliseconds to minimize the tendency of the LC directors to change orientation. The fringe fields passing through the pores 30 in the column electrodes 28 and 29 from the row electrodes 24 and 25 are vertical to hold the LC directors in the vertical position subsequent to the row voltage pulse. The voltage at the row electrodes returns to ground potential subsequent to the pulse, but the column driver square wave provides the voltage which maintains a reversing vertical fringe field through the pores 30. The pulse of 2 V o on the row electrodes plus V o on the column driver, as described above, is strong enough to produce a stronger fringe field which moves the boundary layer of LC directors to the vertical position. The fringe field technique described above eliminates the need of high electrode voltages and high fringe fields which greatly shorten the life of the LC media. | A four terminal liquid crystal display device includes orthogonally related row and column electrodes separated by a dielectric and disposed in respective sets above and below the liquid crystal medium. The electrodes in proximity to the LC medium are the column electrodes which have a small alternating square wave bias voltage±Vo imposed therebetween so that a voltage of 2Vo magnitude is normally impressed across the LC medium. When an impulse voltage of magnitude 4Vo is impressed across the exterior row electrodes (+2Vo and -2Vo respectively), since the column electrodes are foraminated or have microapertures therethrough, the electric field established between the row and column electrodes in opposite sets, 3Vo, extends through the microapertures into the LC medium to establish a fringe electric field normal to the surfaces of the column electrodes tending to retain the LC directors in the vertical position. This arrangement avoids the imposition of large voltages directly across the LC media and permits the application of low voltages to the electrodes and thereby increases the life of only the column LC media which are otherwise degraded by high voltages. | 6 |
BACKGROUND OF THE INNENTION
[0001] 1. Field of the Invention
[0002] This invention relates to a method for operating a mass flowmeter that employs the Coriolis principle and encompasses a measuring tube through which flows a medium, wherein the measuring tube is stimulated into oscillating, and the resulting oscillatory response of the measuring tube is measured.
[0003] 2. Description of Prior Art
[0004] A similar method has been described earlier for instance in DE 100 02 635 A1. According to that document, the measuring tube is stimulated in three mutually different oscillating modes, and by means of the recorded oscillatory response pattern of the measuring tube, the characteristic values of the mass flowmeter such as its zero point and its sensitivity are determined during the operation of the mass flowmeter with the aid of a mathematical-physical model.
[0005] Determining the zero point and sensitivity as the characteristic values during the operation of the mass flowmeter essentially serves the purpose of improving the accuracy of the mass flow measurements. But with a Coriolis-type mass flowmeter, it is additionally possible to measure the pressure of the medium flowing through the measuring tube. One approach frequently employed to that effect in conventional mass flowmeters has been to measure the expansion of the measuring tube, for instance with the aid of strain gauges. The pressure value thus obtained as an additional measured variable can be used, for instance, to correct for pressure-induced errors in other quantities to be measured. To be sure, this always requires additional pressure-measuring provisions such as the aforementioned strain gauges.
SUMMARY OF THE INVENTION
[0006] It is therefore the objective of this invention to introduce a method for operating a mass flowmeter in which, in elegant fashion, the pressure in the measuring tube can be determined without any additional devices. Expanding on the above-described method, this objective is achieved by determining the pressure of the medium flowing through the measuring tube in that the detected oscillatory response is evaluated with the aid of a physical-mathematical model for the dynamics of the mass flowmeter.
[0007] Specifically, according to the invention, the measuring tube is caused to oscillate by an excitation that can vary substantially depending on the intended application, for instance a stimulation at one or two mutually different frequencies and/or one or two mutually different natural oscillating modes, whereupon the oscillatory response of the measuring tube is collected, and by means of a physical-mathematical model that reflects the oscillatory response to a predefined oscillation stimulation, the pressure in the measuring tube is calculated.
[0008] Specifically, one preferred embodiment of the invention provides for the use of at least a second-order physical-mathematical model for the dynamics of the mass flowmeter. Incidentally, it should be noted that in addition to the described oscillation excitation modes for the measuring tube at one or two mutually different frequencies and/or in one or two mutually different natural oscillating modes it is possible, of course, to generate oscillations at other additional frequencies and/or natural oscillating modes. What matters is that the physical-mathematical model employed is capable of providing information on the expected oscillatory response to a predefined oscillation excitation of the measuring tube.
[0009] Accordingly, in a preferred embodiment of the invention, the physical-mathematical model is capable of describing the oscillations of the mass flowmeter upon stimulation of the measuring tube in at least one natural oscillating mode. Any natural oscillating mode will serve the purpose, especially the first and second natural oscillating modes. Another preferred implementation of the invention provides for the physical-mathematical model to include the coupling between the first natural oscillating mode and the second natural oscillating mode of the oscillations of the measuring tube.
[0010] There are many possible approaches to measuring the pressure with the aid of such a physical-mathematical model. In one preferred embodiment of the invention, however, the physical-mathematical model factors in the effective elastic rigidity of the measuring tube. A preferred, enhanced embodiment of the invention includes an operational stimulation and an additional excitation in the first natural oscillating mode of the measuring tube, and a quantification of the effective elastic rigidity of the measuring tube when oscillating in the first natural oscillating mode by means of the resonant frequency of the medium-conducting measuring tube in its first natural oscillating mode, as determined via the operational stimulation and the oscillatory response to the additional excitation. The term “operational stimulation” refers to the excitation of the measuring tube of the Coriolis mass flowmeter for “normal” operation, i.e. for the actual mass flow measurement. The term “additional excitation” as used herein, therefore, refers to an excitation other than the “operational stimulation”, serving to generate additional oscillatory responses.
[0011] In another preferred embodiment of the invention, two additional excitations take place in the first natural oscillating mode of the measuring tube, and the effective elastic rigidity of the measuring tube when oscillating in its first natural oscillating mode is determined on the basis of the oscillatory responses to these two additional excitations.
[0012] As an alternative, another preferred implementation of the invention provides for two additional excitations to take place in the second natural oscillating mode of the measuring tube, and the effective elastic rigidity of the measuring tube when oscillating in its second natural oscillating mode is determined via the oscillatory responses to the two additional excitations.
[0013] Using the physical-mathematical model alone already permits a very precise determination of the pressure in the measuring tube of a Coriolis mass flowmeter. In a preferred embodiment of the invention, however, the determination of the pressure additionally takes into account other factors affecting the dynamics of the measuring tube such as the movement of the support pipe and/or the suspension, if any, of the measuring tube. Also, in another preferred embodiment of the invention, the temperature in the mass flowmeter can be measured to allow compensation for the temperature dependence of the function of certain components of the mass flowmeter system such as an oscillation generator for the measuring tube and/or an oscillation sensor for the measuring tube.
[0014] In a preferred implementation of the invention, the temperature of the measuring tube is also measured to allow for thermally induced changes in the elastic rigidity of the measuring tube to be taken into account when quantifying the pressure. Finally, a preferred embodiment of the invention also factors into the pressure measurement the mechanical stress of the measuring tube and/or of a support pipe by detecting sensitivity variations in the elastic rigidity for the natural oscillating modes of the measuring tube, or by using strain gauges.
[0015] There are numerous ways in which the novel method for operating a Coriolis mass flowmeter can be configured and further enhanced. In this context, attention is invited to the independent patent claims and to the following detailed description of preferred embodiments of the invention with reference to the attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] In the drawings:
FIG. 1 is a schematic illustration of the mechanical configuration of a Coriolis mass flowmeter for use with the respective method according to the preferred embodiments of the invention; FIG. 2 shows one approach to the physical-mathematical model, with concentrated substitute elements, according to the invention; FIG. 3 shows the progression of the elastic rigidity in the first natural oscillating mode of the measuring tube of the FIG. 1 Coriolis mass flowmeter as a function of the operating pressure, and FIG. 4 shows the progression of the elastic rigidity in the second natural oscillating mode of the FIG. 1 measuring tube as a finction of the operating pressure.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0021] As has been explained further above, conventional Coriolis mass flowmeters detect pressure-related changes in the measuring tube with the aid of traditional expansion-measuring techniques, employing for instance strain gauges. The pressure value thus obtained as an additional measured variable can be used to correct for pressure-induced errors in other quantities to be measured. According to the invention, however, the pressure is measured without any additional devices, instead utilizing existing components already serving to quantify the response pattern of the Coriolis mass flowmeter upon oscillatory stimulation.
[0022] According to the invention, the measuring tube acts as a pressure-indicating membrane whose resilience varies as a finction of the pressure in the measuring tube. This variation is detected as a measure of the pressure and is recorded. In the preferred embodiments of the invention described below, the basic concept involves peforming a specifically targeted stimulation of the measuring tube of the Coriolis mass flowmeter and an evaluation of the oscillatory response in such fashion that the stress pattern of the measuring tube as a function of the pressure in the measuring tube is measured via the effective elastic rigidity of the measuring tube in at least one natural oscillating mode.
[0023] FIG. 1 is a schematic illustration, to wit a longitudinal sectional view, of a Coriolis mass flowmeter, showing its mechanical configuration that lends itself to the method here described and applied in the preferred embodiments. It should be pointed out that the method according to this invention is not limited to the Coriolis mass flowmeter configured as shown in FIG. 1 . On the contrary, essentially any tube geometries including designs with only one oscillation generator or even dual-tube configurations can be employed.
[0024] The FIG. 1 Coriolis mass flowmeter encompasses a measuring tube 1 , a support pipe 2 and a protective tube 3 , two oscillation generators 4 and two oscillation sensors 5 . The one measuring tube 1 is of a straight linear design and the Coriolis mass flowmeter depicted in FIG. 1 can be installed, with flanges 6 , an existing pipeline system, not illustrated. The connection between the flanges 6 and the system consisting of the measuring tube 1 and the support pipe 2 is in the form of mounting sections referred to as suspensions 7 . In addition, a central spring 8 provided in the center of the measuring tube 1 connects the measuring tube with the support pipe to enhance the rigidity of the measuring tube 1 , as described, for instance, in DE 42 00 060 A1.
[0025] FIG. 2 shows a model insert, designed for the physical-mathematical model employed in this case, with concentrated substitute elements of the FIG. 1 Coriolis mass flowmeter. The significant mechanical movements of the Coriolis mass flowmeter as shown in FIG. 1 represent the oscillations of the measuring tube 1 and the support pipe 2 in the first natural oscillating mode and in the second natural oscillating mode. They can be described on the basis of the oscillation pattern of the model shown in FIG. 2 . The substitute elements marked M describe the respective effective mass, spring and attenuator of the measuring tube 1 ; the elements marked T describe the corresponding parameters of the support pipe 2 . The substitute elements marked A for the respective mass, spring and attenuator are the substitute elements for the suspensions 7 . The indices A and B represent the left and, respectively, the right half of the measuring tube 1 , the support pipe 2 and the suspensions 7 . The spring and attenuator marked Fm account for the fact that the measuring tube 1 is held in a central position by the central spring 8 . Of course, in the absence of a central spring, the corresponding references do not apply. The respective mass marked m accounts for the fact that a larger mass is involved in the oscillations in the first natural oscillating mode of the measuring tube 1 and of the support pipe 2 than in the oscillations of the second natural oscillating mode.
[0026] Corresponding to this model of an oscillation in the first natural oscillating mode is the cophasal translational movement of the respective mass of the measuring tube 1 , the support pipe 2 and the suspensions 7 . One rotation of the outer masses a and b around the axis of rotation x 2 and X 4 corresponds to one oscillation in the second natural oscillating mode. The mathematical description of the oscillation pattern of this system can be derived with the aid of the 2nd Lagrange equation.
[0027] Assuming that the oscillations of the measuring tube 1 in its natural oscillating modes are mutually decoupled, that the movements of the support pipe 2 are ignored and that the suspension does not move, the simplest model for the pressure measment can be a 2nd order model that describes the oscillations of the measuring tube 1 only in its natural oscillating modes v =1, 2, 3 etc. The correlated transfer function is as follows:
G v ( s ) = k v s s 2 + 2 d v ω 0 v s + ω 0 v 2 ( 1 )
[0028] An example of the parameters of this transfer finction for the first natural oscillating mode is this:
k 1 = 1 m Ma + m Mb + m Mm = 1 m 1 ( 2 ) ω 01 = c Ma + c Mb + c Fm m Ma + m Mb + m Mm = c 1 k 1 = c 1 m 1 ( 3 ) d 1 = 1 2 d Ma + d Mb + d Fm ( c Ma + c Mb + c Fm ) ( m Ma + m Mb + m Mm ) ( 4 )
For the second natural oscillating mode it is:
G 2 ( s ) = k 2 s s 2 + 2 d 2 ω 02 s + ω 02 2 ( 5 )
For the parameters of these transfer functions it is:
k 2 = 1 m Ma + m Mb = 1 m 2 ( 6 ) ω 02 = c Ma + c Mb m Ma + m Mb = c 2 k 2 = c 2 m 2 ( 7 ) d 2 = 1 2 d Ma + d Mb 2 ( c Ma + c Mb ) ( m Ma + m Mb ) ( 8 )
The elasticity constant c v , is composed of the elasticity constants of the oscillator components the measuring tube 1 , the support pipe 2 , the central spring 8 , etc. It depends on the respective module of elasticity of the components, their shape and their location and will vary with the variables pressure and temperature. Moreover, the oscillation amplitude and profile have an effect on the resiliency.
[0029] As a whole, the elasticity constant is a function of numerous process and measuring parameters:
c=f ( T,ΔT,σ,Δσ,P,{dot over (m)}, {dot over ({circumflex over (x)})} ,Formulation . . . ) (9)
[0030] This functional relationship between the influencing variables and the elasticity constant c is very complex and permits only limited description in analytical terms. Still, under certain conditions, it can be used for the indirect measurement of pressure as a process variable. For determining the elasticity constant c v and from it the process pressure, the Coriolis mass flowmeter is additionally stimulated at one or several frequencies, the transfer finction is measured and, based on the result, the rigidity values c v , are calculated. Appropriate calibration will establish the relation between the elasticity constants and the operating pressure. Described below are several preferred embodiments of the invention in both the first and second natural oscillating modes. They can be applied in corresponding fashion with other natural oscillating modes as well.
[0000] Determination of the Elastic Rigidity in the First Natural Oscillating Mode Via a Single Additional Excitation
[0031] The defining equation for the elasticity constant c 1 , is as follows:
c 1 =ω 2 01 m 1 . (10)
The effective mass obtained via an additional excitation at the additional frequency ω Zl after a few transformations will be:
m 1 = ω z1 ( ω 01 2 - ω Z1 2 ) · Im { G 1 ( j ω Z1 ) } Im { G 1 ( j ω Z1 ) } 2 + Re { G 1 ( j ω Z1 ) } 2 . ( 11 )
Provided there is adequate separation between the additional excitation and the resonant frequency, the Equation ( 11 ) can be simplified to read:
m 1 = ω Z1 Im { G 1 ( j ω Z1 ) } ω 01 2 , ( 12 )
while the elasticity constant is derived from:
c 1 = ω Z1 Im { G 1 ( j ω Z1 ) } . ( 13 )
In selecting the frequency position of the additional excitations it is necessary to weigh the trade-off between the highest possible amplitude of the measuring signals—with the frequency response of the transfer fuinction G 1 and, respectively, G 2 declining above and below the resonant frequency at—20[dB] per decade—and an adequate distance from the operating frequency ω ol in order to ensure good signal discrimination. This also applies to the preferred embodiments of the invention described below.
Determining the Elasticity Constants Via Two Additional Excitations in the First Natural Oscillating Mode
[0032] The parameter c 1 as a measure of the process pressure can be determined, corresponding to the operating frequency and without using the natural frequency, through excitation at a minimum of two additional frequencies in the first natural oscillating mode.
[0033] The defining equation for the mass c 1 is:
c 1 = ω ZA ω ZB ω ZB 2 - ω ZA 2 ω ZB Im { G 1 ( j ω ZA ) } Im { G 1 ( j ω ZA ) } 2 + Re { G 1 ( j ω ZA ) } 2 - ω ZA ω ZB ω ZB 2 - ω ZA 2 ω ZA Im { G 1 ( j ω ZB ) } Im { G 1 ( j ω ZB ) } 2 + Re { G 1 ( j ω ZB ) } 2 . ( 14 )
In theory, the position of the additional frequencies has no bearing on the pressure measurment. In reality, however, there is a minor dependence, making it desirable to tie the position of the additional frequencies to the operating frequency in symmetrically mirrored fashion.
[0034] The elasticity constants c v , can in general be determined as a measure of the process pressure upon excitation at a minimum of two additional frequencies in the second or a higher natural oscillating mode.
[0035] The defining equation for the elasticity constant c v is:
c v = ω ZA ω ZB ω ZB 2 - ω ZA 2 ω ZB Im { G v ( j ω ZA ) } Im { G v ( j ω ZA ) } 2 + Re { G v ( j ω ZA ) } 2 - ω ZA ω ZB ω ZB 2 - ω ZA 2 ω ZA Im { G v ( jω ZB ) } Im { G v ( j ω ZB ) } 2 + Re { G v ( j ω ZB ) } 2 . ( 15 )
In the case of the additional excitations, one of the excitation frequencies could coincide with the resonant frequency of the mode concerned. However, the additional frequencies are preferably selected in a symmetrically mirrored position relative to the resonant frequency ωhd 01 .
[0036] It is generally possible to determine the value of the transfer function G v , at a frequency ω for instance from the ratio between the oscillatory response V v , and the oscillation stimulation F v :
G v ( j ω ) = V v ( j ω ) F v ( jω ) . ( 16 )
The oscillation stimulation F v , is a physical stimulation of the measuring tube 1 in its natural oscillating mode vfor instance by means of electromagnetic actuators. The oscillatory response V v , represents the speed of the transverse movement of the measuring tube 1 in its natural oscillating mode, measured, for instance, via the induced voltages that are proportional to the speed, on one or several electromagnetic sensor or sensors. Other actuatiors and sensors may lead to a modified Equation ( 16 ). For example, sinusoidal signals A v , from acceleration sensors can be converted into speed data in accordance with the following relationship:
V v ( jω ) = 1 jω A v ( jω ) ( 17 )
Correspondingly, for sinusoidal signals S v , for instance from optical sensors and proportionally reflecting lateral excursions, it will be:
V V ( j ω)= jω·S v ( jω ). (19)
Relationship Between Process Pressure P and Elasticity Constant c v
[0037] The relationship between the elasticity constant c v , and the process pressure P is:
p=f ( c v ,T , . . . ). (19)
and in specific cases:
P=k v ·c v +k 0v ·c 0v ( T ). (20)
The proportionality factor k v , and, respectively, k 0v , is a design parameter which for a given natural oscillating mode can be viewed as a constant over a certain pressure-measuring range. It can also be established through calibration. The elasticity constant C 0v is temperature-dependent and describes the zero point of the characteristic curve for the natural oscillating mode concerned. It can be corrected with the aid of the measured temperature.
[0038] In typical Coriolis mass flowmeters, the elasticity constants depend only to a minor extent on the oscillation amplitude and, accordingly, the effect of the oscillation amplitude on the pressure measurement can be ignored. For systems with a more dynamic amplitude and consequently greater amplitude dependence, an on-line correction of the oscillation amplitude is possible.
[0000] Compensation for Cross Sensitivities
[0039] The relationship between the elastic rigidity and the pressure in the measuring tube 1 is also affected by other process variables. Correction for the thermal effect on the elastic rigidity is possible by measuring the temperature of the measuring tube 1 . The effect of stress distortions can be compensated for, where necessary, by determining the sensitivity variations of the elastic rigidity in the different natural oscillating modes or by installing in the Coriolis mass flowmeter tension indicators such as strain gauges.
[0000] Experimental Results
[0040] For experimental purposes, a vertically mounted Coriolis mass flowmeter was connected to a pressure-gauge test pump that is capable of generating static pressures up to a maximum of 60 bar (870 psi). About every ten minutes during the test, the pressure was set at a different value, which in each case remained essentially constant for a ten-minute time span (maximum pressure drop 2 bar (29 psi) after an initial pressure of 50 bar (725 psi)).
[0041] FIGS. 3 and 4 show the measured results obtained with distilled water as the medium flowing through the measuring tube 1 . As is quite evident, the pressure-related change in the elastic rigidity is conspicuously detected by means of the model-based quantification of the elastic rigidity cv. | A method for operating a mass flowmeter that employs the Coriolis principle and through which flows a medium, the flowmeter including a measuring tube through which passes a medium, which measuring tube is stimulated into oscillating and the resulting oscillatory response of the measuring tube is measured includes the step of gauging the pressure of the medium flowing through the measuring tube by evaluating the collected oscillatory response on the basis of a physical-mathematical model for the dynamics of the mass flowmeter. Thus, without requiring any additional devices, it is possible for a Coriolis mass flowmeter, apart from measuring the mass flow, to also measure the pressure in the measuring tube. | 6 |
BACKGROUND OF THE INVENTION
Hitch mechanisms for trailers have taken a wide variety of different forms. For example, one type of mechanism used when the trailer is being attached to a tractor, includes a "V" opening to receive the king pin of the trailer when the tractor is being moved into position. After the king pin has been inserted into the opening, the hitch mechanism is closed to maintain the trailer attached to the tractor.
On so-called "piggy back" systems, a trailer is carried by a freight car. In these cases, the trailer is generally physically lifted, moved over the freight car and then lowered vertically with the king pin of the trailer being lowered into an opening of the hitch mechanism mounted to the freight car.
In the past, many such hitch mechanisms used in "piggy back" systems have involved movable locking elements which are opened or closed by screw mechanisms. For example, when the hitch is opened, a screw mechanism is in a first position. After the king pin of the trailer has been lowered into the opening of the hitch, a wrench is used to turn the screw mechanism to close the hitch. Additional safety means are sometimes then employed to maintain the hitch in a locked position.
The present invention is directed toward mechanisms specifically designed for freight cars for receiving and transporting a trailer. While the hitch mechanisms used heretofore have proven satisfactory in many cases, they have often required special tools to open and close the hitches. This sometimes is inconvenient and time consuming. Also, the additional safety means used to keep the hitch mechanisms closed often required a conscious manual operation of the person operating the hitch, an operation which may be overlooked.
OBJECTS OF THE INVENTION
It is an object of this invention to provide an improved hitch mechanism for a freight car for securing a trailer in place as it is being transported.
It is a further object of this invention to provide an improved hitch mechanism for a freight car for securing a trailer in place during transit in which no tools are required to open and close the hitch mechanism.
It is still a further object of this invention to provide an improved hitch mechanism for securing a trailer to a freight car during transit which includes an additional automatic safety lock after the hitch mechanism is closed and which requires a manual release before the hitch mechanism can be opened.
SUMMARY OF THE INVENTION
In accordance with the present invention, a hitch mechanism is connected to a freight car, preferably a low-level freight car. The hitch mechanism is adapted to be manually opened or closed by a lever. A spring biased safety latching mechanism is adapted to automatically lock the lever in place when the hitch mechanism is closed. The latching mechanism must be first manually released before the hitch mechanism can be opened. A trailer is adapted to be lowered on to the freight car, with the king pin of the trailer being moved into an opening of the hitch mechanism while it is open. The hitch is then manually closed and automatically locked in place.
Other objects and advantages of the present invention will be apparent and suggest themselves to those skilled in the art, from a reading of the following specification and claims, taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side view illustrating one embodiment of the present invention with a low level freight car carrying a typical trailer;
FIG. 2 is an isometric view of a hitch mechanism embodying the present invention of the type which may be used in connection with FIG. 1;
FIG. 3 is a bottom view of the hitch mechanism illustrated in FIG. 2;
FIG. 4 is a side view taken from the right side of the hitch mechanism illustrated in FIG. 2;
FIG. 5 is a cross-sectional view taken along lines 5--5 of FIG. 2;
FIG. 6 is a cross-sectional view taken along lines 6--6 of FIG. 2; and
FIG. 7 is a cross-sectional view taken along lines 7--7 of FIG. 2.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIG. 1, freight cars 10, 12 and 14 are illustrated carrying trailers 16, 18 and 20, respectively. The trailers may be of the type normally attached to tractors. The freight cars 10, 12 and 14 may be of the low level type, of the type described in copending application entitled "A Low Level Freight Car for Carrying Trailers", Ser. No. 147,965, filed May 8, 1980, and assigned to the same assignee as the present invention.
The trailer 16 includes conventional wheels 22, a trailer hitch mechanism 24 and a landing gear 26. The present invention is directed primarily to the trailer hitch mechanism 24, which will be shown and described in detail in connection with subsequent figures.
The trailer may include various conventional items such as positioning rails 28 and other elements as illustrated. Truck assemblies 30 and 32 are disposed on either side of the freight car unit 10. The truck assemblies 30 and 32 include elements found in conventional railway trucks including wheels associated with axle and brake assemblies. The details of these trucks are only incidentally related to the present invention and will not be shown or described in detail.
In general, in the "piggy back" system illustrated in FIG. 1, require that the trailers be first physically lifted and moved into positions over the freight cars. The trailers are then lowered with their respective king pins moving into openings in their respective hitch mechanisms.
Referring to the other figures of the drawings, FIG. 2 illustrates the hitch mechanism 24 in a closed position. The hitch mechanism includes pedestals 34 and 36 which are adapted to be attached to the mounting plate 35 of a freight car and support the main locking elements of the hitch mechanism 24. The mechanism 24 includes a top head member 38 supported on the pedestals 34 and 36 which holds the various movable locking or hitching elements as will be described. A retainer shaft 40 and block 41 on either side secures the top head member 38 to the pedestals 34 and 36 (FIG. 4).
The head member 38 includes a substantially rectangular opening 42 for receiving the movable members for locking the hitch mechanism 24. A movable jaw 44 is adapted to be selectively moved back and forth to open and close the hitch mechanism 24. When the movable jaw 44 is in a closed position, as illustrated in FIG. 2, a central opening 46 is provided to securely hold a king pin 47 (FIG. 6) of a trailer securely in place. The total opening in the hitch when it is open may be approximately 36 square inches. This makes it relatively easy to locate the king pin of a container into the opening because the diameter of the king pin may be in the order of 2 inches.
The movable jaw 44 is disposed to be opened and closed by a lever mechanism 48. A spring biased latch element 50 locks the lever mechanism in place when the hitch mechanism 24 is closed. The latch mechanism 50 automatically maintains the lever 48 and the movable jaw 44 is in a locked position when the hitch is closed. This provides a safety lock feature which does not require a positive action on the part of the person closing the hitch. When it is desired to open the hitch mechanism, the latch mechanism 50 must be manually operated against a bias of a spring to permit the lever arm 48 to be moved to move the movable jaw 44 out of a lcoking position.
Referring to FIG. 3, the movable jaw 44 is adapted to be moved away or toward a fixed jaw 52. The movable jaw 44 is adapted to be guided by a pair of slide members 49 and 51 (FIG. 6). As illustrated in FIG. 6, the movable jaw 44 include guiding grooves 43 and 45 to receive projection sections from the members 49 and 51, respectively, to permit a sliding and guiding movement of the movable jaw 44 to open or close the hitch mechanism 24.
As illustrated in FIGS. 3 and 5, the lever arm 48 is secured at one end to a pivot connection 54, which includes a suitable bearing, bolt and nut, and is adapted to be manually moved about this connection. The lever arm 48 is also connected by suitable connection beams 58 including a bolt connected to the top plate, bushing and nut. A link arm 59 connects the pivot connection 58 to a pivot connection 62, which also includes a bolt connected to the top plate, and a bushing and nut. When the lever 48 is moved in a clockwise direction with respect to FIG. 3, it is pivoted about pivot point 54 causing the link arm 59 to move to force the jaw 44 to move and open the hitch mechanism 24. In like manner, when it is desired to close the hitch mechanism 24, the lever arm 48 is moved in a counter-clockwise direction to cause the link arm 59 to force movement of the jaw 44 to close the hitch mechanism.
Referring to FIG. 7, the latch mechanism 50 is rotatable about a pivot connection 64. The main latch element 68 includes a cut out groove or hook 70 to receive the lever arm 48 therein.
A compression spring 74 is held by a holder element 73 and is connected between the top plate 38 and a curved cam section 76 in the end of the main latch element 68. The spring has a cap 75 which is forced into the cam portion 76 at the end of the latch element 68 to bias it downwardly about the pivot connection 64. This prevents the lever arm 48 from being moved out of the locked position unless the latch is manually moved by an operator.
When it is desired to move the lever arm 48, it is necessary to move downwardly a handle 72 which is secured to the latch element 68. This movement overcomes the bias of the compression spring 74 to permit free movement of the lever arm 48. | A hitch mechanism connected to a freight car is disposed to receive a king pin of a trailer to be carried by the car. The hitch mechanism is adapted to be selectively opened to receive the king pin therein and then closed by a lever to secure the king pin in place. A latch mechanism automatically locks the hitch mechanism in a closed position after the hitch mechanism is closed. A manual operation of the latch mechanism is required before the hitch mechanism can be opened. | 1 |
FIELD OF THE INVENTION
The invention relates to a method for archiving data, and more particularly, archiving data in a storage server using a runtime monitoring system.
BACKGROUND OF THE INVENTION
Current archiving methods archive files based on their respective last access times, i.e., a file “atime” (last time accessed). For example, a policy may be to archive all files that have not been accessed for more than “x” number of days. Traditional algorithms designed for such an archiving policy typically scan all files in the system on a regular basis, e.g., once per day, and check whether “x” days have passed since the last access for each file. Files that have not been accessed for at least “x” days will then be archived.
Generally, to archive a file if it has not been accessed for some time, requires an archiving module to gather the last file access time, i.e., atime, and the current time, to determine if an archiving criteria is met, such as, to archive when a file has not been accessed for a week. Thus, the atime of the file and the current time are used to make a determination of when the file was last accessed and if the file should be archived.
A disadvantage of typical algorithms used in archiving methods occurs because data has grown exponentially for many business making daily scans of entire file systems for archiving a non-viable solution to archiving needs. For example, millions of files can require hours to scan, leading to significant performance-intrusion to normal production workloads, even though typically, only a fraction of files need to be archived on each day. Scanning numerous files typically found at a business raises issues pertaining to cost, performance, reliability, and availability. Cost-effective information management, including archiving, throughout the information's lifecycle can be of critical importance to a company. Archiving is prominent in the domain of Information Lifecycle Management (ILM).
One solution to managing abundant data is using a leveraging cost-effective tiered storage infrastructure e.g., high end or low end disk storage, where high end disk storage may be server hard drives and low end disk storage may be tapes using tape drives. However, the solutions to the problem of volumous data storage, as well as, accessing such data effectively and efficiently has been directed toward traditional archiving or Hierarchical Storage Management (HSM) technologies, which moves data across tiered storage.
Known, are archiving solutions that archive files based on the last access time of the file. However, the existing archiving technologies typically rely on regular and expensive data repositories or file system scans to determine the archiving candidate files. In typical customer environments, the high-end storage can often host several terabytes of data and the low-end tape storage can keep tens or hundreds of terabytes of data, sometimes even petabytes. A disadvantage of current archiving techniques includes the lack of an efficient technology, system or method for scanning numerous files for archiving and archiving selected files. The lack of such an efficient system or method in the art results in slow and performance intrusive archiving techniques.
It would therefore be desirable to avoid direct file set scans when extracting an atime (last time accessed) from the files and checking if a current time is later than the atime. It would also be desirable for an archiving solution to provide efficient archiving with less runtime performance interference. It further is desirable to provide a scalable and efficient archiving algorithm for large file sets.
SUMMARY OF THE INVENTION
In an aspect of the present invention a method for archiving data in a storage server is provided using a runtime monitoring system. The method includes providing a plurality of data files and creating access logs according to a specified format from the plurality of data files. At least one of the access logs from the plurality of data files is examined and a file will be archived from the examination of the access logs. An archive procedure is initiated for a file when the file has not been accessed for a specified period of time.
In a related aspect, the step of determining if the file will be archived includes ascertaining if the file has a duplicate entry in the access log, and archiving the file when the file does not have the duplicate entry in the access log.
In a related aspect, the specified format is an append only access log.
In a related aspect, the file is not archived if its access log has been examined within a specified time period.
In a related aspect, the plurality of data files are tracked as the data files are created, and the tracking of the plurality of data files may occur when the data files first enter a data storage system which may include a plurality of computer data storage elements.
In a related aspect, the method further includes the steps of determining when the access log is available and not available. When the access log is not available the plurality of data files are scanned to determine if the file will be archived, and the archive procedure is initiated for the file when the file has not been accessed for the specified period of time.
In another aspect according to the invention, a runtime monitoring system for archiving data in a storage server comprises a plurality of data files, and an access monitoring device for monitoring a users accessing of the data files and creating at least one access log according to a specified format from the plurality of data files. A monitoring daemon examines at least one of the access logs from the plurality of data files and determines if an accessed file will be archived from the examination of the at least one of the access logs. The monitoring daemon initiates an archive procedure for the accessed file when the accessed file has not been accessed for a specified period of time.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other objects, features and advantages of the present invention will become apparent from the following detailed description of illustrative embodiments thereof, which is to be read in connection with the accompanying drawings, in which:
FIG. 1 is a diagram depicting an archiving system according to the present invention; and
FIG. 2 is a block diagram of access logs shown in FIG. 1 .
DETAILED DESCRIPTION OF THE INVENTION
Referring to FIG. 1 , an archiving system architecture according to an embodiment of the present invention comprises a runtime monitoring system 10 which includes an access monitor module 18 installed on the storage server 14 , e.g., a file system server, and an archiving daemon 22 . Users or administrators 11 are able to access the storage servers 14 and access local applications or host application on their individual nodes or computers 12 . One computer and user system 11 is shown in FIG. 1 for illustrative purposes, however, it is understood that numerous users and computers are envisioned as accessing the storage servers 14 . The storage servers 14 can access high-end storage, for example, hard drives on servers, and low-end storage 38 , for example, tapes in a tape drive. The module 18 intercepts file accesses, i.e., reads files passed by the host applications to the storage servers and creates an access log file. Thus, the module 18 tracks a file access time “atimes” as they occur.
For each file access, the module 18 appends a record to an append-only log (for example, log 202 shown in FIG. 2 ). The record in the append-only log indicates that an access has occurred on the file. The append-only logs are allocated from the high-end storage space 30 . Since no actual data is logged and only the un-archived files' access information is logged, the log space needed for the method according to the present invention is small. The monitor 18 can also bundle a large number of file accesses into a single large write to a disk log to minimize performance overhead.
An advantage of the present invention over conventional archiving algorithms is that the module 18 of the present invention tracks file atimes in the access log, and therefore does not have to regularly examine all files in an entire file set which can require significant processing time and resources. Thus, by tracking the file atimes as they occur, the method of the present invention avoids file set scans which would require extracting an atime and checking if a current time is later than the atime. Furthermore, archiving system module 18 efficiently identifies archiving candidates by using the access logs to identify the archiving candidates.
The archiving daemon 22 portion of the archiving system 10 installed on the storage server 14 can ran periodically, e.g., daily, or weekly. The daemon 22 examines the append-only access logs 34 , determines which files to archive, and archives them accordingly. The archiving periodicity is a parameter which can be tuned or refined to archive files, for example, once every few hours, or once a day, or once a week. In the exemplary embodiment discussed below, a sample archiving policy is explained which archives all files which have not been accessed for at least “x” days. In practice, “x” is typically on the order of tens of days, e.g., 30 days. It is envisioned that if users wish to use smaller time units, e.g., hour or minute, instead of a day to define the archiving policy, the scan-free algorithm of the present invention can be easily modified to accommodate such requirements.
When the archiving unit is, for example, a day, the archiving daemon 22 can be invoked once a day to extract the files that have become qualified for archiving on that day and archive them accordingly. The invocation interval or the archiving interval defines the time between two successive archiving daemon invocations. An archiving interval can be larger than the archiving unit itself, e.g., a multiple of archiving units such as “n” days. In such cases, the archiving daemon is invoked once every “n” days. In general, files that have not been accessed for the last x+n, x+n−1, . . . , x+1, and x days can all be archived by the time the archiving daemon is invoked. When n>0, multiple days of accessed files may be batched together. The archiving daemon may delay archiving of some of the qualified files. For instance, when n=2, the archiving daemon is invoked once every 2 days. When the archiving daemon is invoked, there may be files that have not been accessed for x+1 and x days. The archiving daemon can archive all such files at one time. However, if n=0, there will be only files that have not been accessed for x days. Clearly, a small “n” ensures that the archiving is done more precisely and timely. A large “n” may delay archiving of old files that are no longer needed. Without archiving them away promptly, they can take up valuable space in high-end storage for unnecessary amounts of time, which also leads to suboptimal resource utilization.
The described archiving architecture/runtime monitoring system 10 according to the present invention includes monitoring and archiving. Both monitoring and archiving incur performance overheads. Monitoring is directed to how to efficiently track the file access information to facilitate the archiving candidate file identification. Archiving is directed to how to utilize the tracked file access information to identify the candidate files efficiently.
A preferred embodiment of the archiving method according to the present invention includes an append-only update archiving method to logically remove the log records from the logs as needed. Specifically, if a file “F” is accessed on day “i” and “k”, where “k” is the most current day, i.e., (k>i), a log record for “F” is simply appended to the end of the log L i , hence the name “append-only update”. Later, when the archiving daemon examines log L i to identify candidate files for archiving, the archiving daemon knows that all files that have duplicate log record entries cannot be archived, since they must have been accessed on an later day. Thus, only the files that do not have duplicate entries can be archived, since they must have not been accessed for the last “x” days.
The append-only update method described above avoids scanning either the access logs or file systems. Furthermore, the monitor 18 can batch multiple updates to the same log into one append by first sorting the log records by their old atimes, and then updating all records that belong in the same log at once. This further improves the monitoring performance.
An exemplary append only update method is shown in FIG. 2 . The log memory 100 includes log 060105 ( 202 ), log 060205 ( 204 ), log 062005 ( 206 ), and log 070105 ( 208 ). Log 202 includes files 1 - 3 , 104 , 108 , and 112 , respectively. To archive the files, the archiving daemon 22 can read the entire log in memory 100 , filter out the duplicate file entries file 1 and file 2 , 104 and 108 , respectively, and then archive the remaining file entries. Using the append-only update method, duplicate file records may be seen in each log L i . However, there cannot be more than two records for each file. This is because if a file is accessed on day “i” and a later day “j”, there must be a new file record created in log L j . For subsequent access to the same file, only log L j will be updated, but not L i . If the original log size for L i is “s” when L i was initially created, then the maximum size for log L i is 2×s. This case may happen when all files accessed on day “i” were accessed on a later day before they are archived.
Depending on the available memory space, the archiving daemon may or may not be able to read the entire log L i into memory at once for processing because each of such logs can be tens or hundreds of MBs. If the memory space is not large enough to hold the entire log, the archiving daemon can divide the log into pieces and work on one piece at a time.
For each piece, the archiving daemon checks if all the file records have duplicate entries in the file records which are already read, if not, the file can be archived. Additional optimizations are possible to work with even smaller memory spaces by converting filenames into hash values rather than using absolute filenames. A hash function can use, for example, substitution or transposition of data to create a fingerprint, i.e., a hash value, which can be represented as a short string of random-looking letters and numbers.
For example, if the storage server has enough memory space for log processing, the append-only update will not need to break the log into multiple smaller pieces. For an append-only update, the monitoring costs include a new log write and appending to the “N” old logs if “N” files must be updated. Unlike the method of the present invention, traditional archiving incurs significant amount of random disk I/Os (input/output) simply to identify archiving file candidates. The append-only update incurs significantly less overhead because the monitor and archiving only needs to update logs and process them once a day.
In one scenario, an access buffer may be lost due to a storage server crash, which raises an issue of crash recovery. In the present invention, access logs may be buffered and the writes to the access logs are delayed. Thus, if there is a crash during the day, the entire buffer may be lost. This would result in the loss of the file accesses which occurred on that day, resulting in the archiving daemon not archiving all files that are qualified for the specified conditions. This problem may be resolved by having a separate daemon to scan the entire file system periodically, or initiating the entire file system scan after the access logs are found to be unavailable to retrieve the files that were missed from a normal archiving invocation due to the loss of an access buffer.
Thus, the append-only access log structure for tracking file accesses according to the present invention discloses an efficient and highly scalable archiving method, that archives files without expensive file system scans. The present invention introduces little runtime overhead for normal accesses while significantly reducing the archiving time because of the append-only access log structure for tracking file accesses and a runtime monitoring mechanism that tracks the file accesses as they occur.
Another technique to minimize runtime overhead may include merging into a single file multiple accesses which occurred on the same file during a time delay. The time delay is incurred while the access monitor delayed the writing of log records for accessed files by using a memory access buffer.
Another method according to the present invention includes avoiding log scans by keeping the access log records in the access log up-to-date. For example, if a file “F” is accessed on day one and day i (i>1), when day i's log record is written to the access log, the log record for F on day one can be logically removed from the log because the file was accessed after day one. Thus, the access log will contain only one access log record per file, and when the archiving daemon is invoked on, for example, the last day of the month, the portion of access log for day one will only contain the log records for files that have not been accessed for the month. All other files should have been logically deleted as they are accessed later on in the month. Using this method, there are only unique file records in the log.
Another method for archiving includes sequential log sequencing. Since the access records are typically bundled into large writes, the monitor creates one access log for each log write. The access logs also have a special naming scheme to allow the archiving daemon to easily identify them without searching through the entire log directory. For instance, if a log is created daily, the log name can be constructed as “log.date” where “date” indicates the date on which the log is created. This is effectively creating a log deliminator that separate one day's log from another. As shown in FIG. 2 , the logs have different log names 202 - 208 to indicate different days logs. Any delimitation scheme may be used as long as the monitor and archiving daemon can identify the desired portions of the access log, e.g., for a particular day.
To avoid scanning the access logs, the access monitor keeps track of an additional piece of information in memory as each file is accessed. That is, when a file “F” is accessed, the monitor records the last atime before the atime is updated to the current access time. The old atime indicates when “F” was accessed last. Such information allows the monitor to easily compute which access log would contain a record for “F” and hence needs to be updated. Specifically, if the last atime was “n” days ago, the access log that was created “n” days ago must contain a log record for “F”. That record can now be removed since more recent accesses of the file F have occurred after that day. The old atime can be extracted without any additional overhead when the atime field is updated.
Thus, when the monitor is about to write out the entire access record buffer to a new access log “k”, for each file record in the buffer, it checks its old atime and determines if the file was accessed on an earlier day based on that atime. If so, the corresponding log should be updated, otherwise, only a new log record will be written in the log created for day “k”. Updating old access logs must be done with care to avoid a large number of random disk I/Os. In particular, the monitor can batch the updates to the same log L i together to avoiding multiple random updates to L i .
While the present invention has been particularly shown and described with respect to preferred embodiments thereof, it will be understood by those skilled in the art that changes in forms and details may be made without departing from the spirit and scope of the present application. It is therefore intended that the present invention not be limited to the exact forms and details described and illustrated herein, but falls within the scope of the appended claims. | A method is disclosed for archiving data in a storage server using a runtime monitoring system. The method includes providing a plurality of data files and creating access logs according to a specified format, which may include an append only access log, from the plurality of data files. At least one of the access logs from the plurality of data files is examined and a file will be archived from the examination of the access logs. An archive procedure is initiated for a file when the file has not been accessed for a specified period of time. If the file will be archived includes ascertaining if the file has a duplicate entry in the access log, and archiving the file when the file does not have the duplicate entry in the access log. | 6 |
FIELD OF THE INVENTION
The invention relates to a method of encoding lines in a print from the skin, and particularly a fingerprint.
BACKGROUND OF THE INVENTION
To allow fingerprints to be identified, images of the fingerprints are analyzed, this being done by extracting characteristic features, particularly endings and branchings of the ridges on the skin, and comparing them with reference features that are held in store.
To enable the characteristic features to be extracted, it is necessary for the images to be pre-processed and the details produced by the pre-processing to be pre-processed and stored. A step that is frequently taken as part of the pre-processing is so-called skeletonization, in which the ridges, which are a plurality of picture elements (pixels) wide, are reduced to lines only one pixel wide. Before this is done, the brightness levels are turned into binary values. To store a line of this kind, all the raster dots that go to make up the line therefore have to be stored in the memory together with their co-ordinates. Given the large number of lines that there are, this takes up a considerable amount of space in the memory.
It is therefore an object of the invention to encode the lines in a manner that reduces the data without there being any loss of the information required for structural analysis.
SUMMARY OF THE INVENTION
This object is achieved in accordance with the invention in that one line at a time is encoded by means of vertices, which include the starting point and the end point, that are situated on the line, such that connecting line segments between adjacent vertices are no more than a preset distance away from the line.
It is not only a saving in storage space that is made possible by the method according to the invention. The subsequent structural analysis, and particularly the extraction of characteristic features, takes places faster and more easily than with a binary image that comprises the skeletonized ridges. Depending on the methods that are employed for the purpose, it is enough for only the vertices to be covered, without the line as such having to be decoded by calculating other points situated on the segments of connecting line.
One embodiment of the method according to the invention makes it possible for the vertices to be determined in a particularly advantageous way in that, after the starting point and the end point have been determined, a search is made for that point on the line that is the maximum distance away from a connecting line between the starting point and the end point, the point that is the maximum distance away is stored as a first vertex, a search is made, between the first vertex and the starting point and the end point, for other points that are the maximum distance away from their associated segment of connecting line, the points that are found constitute a second and a third vertex, between which and the starting point, the end point and the first vertex a search is made for further points each at the maximum distance, which further points form further vertices, and a search of this kind is continued until such time as no point is found that is at a distance greater than the preset distance.
The preset distance will depend on various attributes of the print from the skin, such as on the distance between the lines and the maximum curvature of the latter. It has proved advantageous in practice if the preset distance is less than a third of the distance between the lines.
The branchings in ridges that occur in prints from the skin can be allowed for in the method according to the invention by splitting branching lines apart at the branch. When this is done, it has proved advantageous if all three limbs of the branch are each processed as single lines. The splitting-apart then also causes a starting point and an end point to be defined for each of these lines.
Where there are closed lines, which also occur in prints from the skin, provision may be made in the method according to the invention for closed lines to be broken open. A starting point and an end point are then defined for the broken-open line too.
In an advantageous embodiment of the method according to the invention, the perpendicular from the given point to the straight line comprising a connecting line is calculated when determining a distance from the connecting line. However, where there are pronounced curvatures, this embodiment may, under certain circumstances, produce errors but it does impose only a relatively small burden in terms of calculation.
Another embodiment of the method according to the invention allows distance to be determined correctly even in cases where there are pronounced curvatures and involves the distance between one point at a time and a connecting line or segment thereof being calculated as the distance to the start or end of the connecting line or segment thereof if the perpendicular from the given point to the straight line containing the connecting line or segment thereof is not situated on the connecting line or segment thereof.
These and other aspects of the invention are apparent from and will be elucidated with reference to the embodiments described hereinafter.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1 shows a skeletonized fingerprint,
FIG. 2 is a diagrammatic view of a skin ridge that has been skeletonized into a run of line,
FIG. 3 shows representations relating to the determination of the distance of a point from a connecting line.
FIG. 4 shows a line that is being encoded by the method according to the invention.
FIG. 5 shows a program for carrying out the method according to the invention in the form of a flow chart, and
FIG. 6 is a more detailed view of part of the flow chart shown in FIG. 5 .
DESCRIPTION OF PREFERRED EMBODIMENTS
FIG. 1 shows a fingerprint, after pre-processing into the form of a raster image in binary form made up of, for example, 250×350 pixels, which may each assume a value of 0 or 1 (black or white). The image contains various lines 1 that have starting points 2 , end points 3 and branchings 4 .
FIG. 2 is a diagrammatic view of one of the skeletonized lines, each of which is only one pixel wide. A line connecting the centers of the pixels making up the skeletonized line represents a run of line of which the individual points would, without the method according to the invention, have to be stored together with their co-ordinates.
To enable the lines 1 to be individually encoded, in a first step of the method the end points and branch points are found in the skeletonized image. This is done by known methods. For this purpose, a search is, for example, made for points having the binary value representing a line (black in the Figures) that have only one neighbor of the same binary value. In the case of branchings, a search is, for example, made for points that have more than two neighbors.
This produces lines that each have a starting point and an end point. By a tracing process, these lines are each converted into an array of points, the co-ordinates of the points of one run of line at a time being stored in a memory in the sequence in which they are found in the tracing process.
To enable the storage space required to be reduced, a check is now made to see which of the inner points along each line are required (i.e. “necessary”) to represent the line to within a preset standard of accuracy. The standard laid down for this purpose is that none of the points in the original run of line should be more than a preset distance away from the reduced run of line. Before the method proper is considered, two ways of determining the distance between a point and a connecting line between the two ends of a run of line AB will be explained by reference to FIG. 3 .
In the variant shown in FIG. 3 a , all that is done is to determine the distance to the straight line that extends through the ends A and B. This is enough whenever, for any point whose distance from the straight line is at most the preset distance h, the distance to the connecting line is likewise at most h.
In FIG. 3 a , equidistant straight lines are shown in parallel with the straight line passing through A and B. This method can lead to errors in the case of lines having very pronounced curvatures, which is avoided in the case of the method shown in FIG. 3 b . In this case, it is the actual distance from the connecting line between A and B that is determined, for which purpose it has to be established whether the perpendicular from the point to the straight line meets the straight line inside or outside A and B. In the first case, it is the distance to the closer of points A and B that is determined and in the second it is the distance to the connecting line, i.e. to the foot of the perpendicular. When use is being made of the method of determining distance shown in FIG. 3 b , the binary image taken as a basis may contain any desired structures.
FIG. 3 c again makes clear how distance is determined for a point C. With the method shown in FIG. 3 a , a distance of less than h would be determined, which is clearly not the case. With the method shown in FIG. 3 b however, the distance is determined as equal to the distance between C and B.
FIG. 4 illustrates individual steps in the method according to the invention by taking a line 1 as an example. First, as shown in FIG. 4 a , a connecting line 5 is formed between the end points x 1 and x 9 of the line 1 , which latter is, for example, initially made up of approximately 300 points. Next, that point on the line which is the greatest distance away from the connecting line 5 is calculated, namely point x 5 in the present example. Segments 6 , 7 of connecting line are formed in turn from point x 5 to points x 1 and x 9 respectively ( FIG. 4 b ). In the view shown in FIG. 4 c are shown those points x 3 and x 7 that are the maximum distances away from the segments 6 , 7 of connecting line ( FIG. 4 b ), which points x 3 and x 7 in turn form starting points for further segments 8 , 9 , 10 , 11 of connecting line, a process which in turn generates intermediate points x 2 , x 4 , x 6 and x 8 ( FIG. 4 d ).
After the calculation of each of the segments 5 to 19 of connecting line, a check is made to see that none of the points on the line 1 , between the points x 1 to x 9 defining a given segment of connecting line, is a distance greater than h away from the segment of connecting line ( FIG. 3 ). If none of them is, a new vertex is not formed on the relevant portion of line. Once there is no point along the whole of the line that is further away than the corresponding segment of connecting line, then all the vertices are determined and are then entered in an array that fully defines the line to within the standard of accuracy required. In the example shown, the nine points x 1 to x 9 shown in FIG. 4 d are all that are needed rather than the original 300 points.
In a study of 880 fingerprints, it was found that an average number of 275 points were required to represent or encode one complete fingerprint by the method according to the invention. In less than 2% of all the cases were more than 400 points required. If it is assumed that the position of a point can be stored in two bytes and that approximately another 100 bytes will be needed to separate the individual runs of line from one another in the memory by end markers, then a fingerprint can be stored in less than 1 kB with the method according to the invention. Uncompressed, even if stored bit by bit, a binary image measuring 256×384 pixels on the other hand requires 12 kB.
Added to the reduction in storage space, there is also another advantage that the invention has, namely that the vectorial representation allows a detailed structural analysis to be carried out. It is easier for the ridges to be examined for their length and direction. It is easier to find which minutiae are situated on a common ridge or how many ridges may, in a given case, be situated between two minutiae. The removal of artifacts (bridges, spurs, islands), which constitutes a major part of the work done to process fingerprints, is made easier.
FIG. 5 shows a program for carrying out the method according to the invention in the form of a flow chart. After the start at 21 , an image that has already been skeletonized ( FIG. 1 ) is read in at 22 , as also is a preset tolerance h. This is followed at 23 by the skeleton image being split up into individual lines. At 24 the lines are traced, thereby generating arrays of the points forming the lines. In the next step 25 of the program, which is performed for each of the lines obtained at 23 , vertices are determined as shown in FIG. 4 . The steps in the program that are involved here will be explained in detail in connection with FIG. 6 . Once the vertices have been found for all the lines, the program is brought to an end at 26 .
The program shown in FIG. 6 is run for each of the lines. To start, the index of the first vertex, namely the starting point of the given line, is pushed onto a first stack at 31 and the index of the last vertex, namely the end point, is pushed onto a second stack. Next, the starting and end points are marked as “necessary”. After a branch at 33 , the two indexes idx 1 and idx 2 are popped from their respective stacks at 34 , provided the stack is not empty. As was described in connection with FIG. 4 , at 35 a search is made between points x 1 and x 2 for that point whose distance from the run of connecting line is a maximum.
If a point of this kind is found, a check is made at 36 to see whether the distance is greater than the tolerance h. If this is not the case when even the first vertex situated along the course of the line is calculated, then this vertex is not “necessary” because what is involved is a straight line within the tolerance h. The program is brought to an end after the branch at 33 by rebuilding the array from the “necessary” vertices in step 37 of the program, that is to say by deleting all the points on the line except the starting and end points.
If, however, the distance dmax is greater than h, then at 38 index idx 1 is pushed onto stack 1 and the index idxmax for the point at the maximum distance is pushed onto stack 2 , whereupon, at 39 , the index idxmax for the point at the maximum distance is pushed onto stack 1 and the index idx 2 for the end point is pushed onto stack 2 . In this way, prerequisites have been met to allow a search to be made for further points between points x 1 , x 5 and x 9 , the point at the maximum distance (point x 5 in the program loop) having first been marked as “necessary” in step 40 of the program.
After this, a check is again made at 33 to see whether the stack is empty. This, however, will not be the case if a new vertex was found at 35 . The next program loop then produces points x 3 and x 7 . After this, points x 2 , x 4 , x 6 and x 8 are found. In the case described in connection with FIG. 4 , dmax will not be greater than h in a further loop, whereupon it will be found at 33 that the stack is empty and an array of the “necessary” vertices will be compiled at 37 . | In a method of encoding lines in a print from the skin and particularly a fingerprint, one line at a time is encoded by means of vertices, which include the starting point and the end point, that are situated on the line, in which case segments of connecting line between adjacent vertices are no more than a preset distance away from the line. | 6 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of U.S. patent application Ser. No. 13/531,227, entitled “Method And Devices For Flow Occlusion During Device Exchanges,” filed on Jun. 22, 2012, which claims priority to U.S. Provisional Patent Application Ser. Nos. 61/501,125, entitled “Methods, Devices, and Systems for Flow Occlusion During Device Exchanges,” filed on Jun. 24, 2011; and 61/540,994, entitled “Method and Devices for Flow Occlusion During Device Exchanges,” filed on Sep. 29, 2011. This application is related to U.S. patent application Ser. No. 11/112,877, entitled “Apparatus and Methods for Sealing a Puncture in Tissue,” filed on Apr. 22, 2005, and now issued as U.S. Pat. No. 8,002,742. The full disclosures of these references are hereby incorporated by reference.
FIELD
[0002] The field of the present application pertains to medical devices, and more particularly, to methods and systems for maintaining vascular access and/or minimizing bleeding, for example, during and after catheter-based interventions, for example, in the settings of device exchanges, vascular access closure, and the management of vascular complications.
BACKGROUND
[0003] Catheter-based medical procedures using large diameter (or “large bore”) vascular access sheaths are becoming increasingly more common. Two examples of such large bore catheterization procedures that are gaining rapid popularity are Transcatheter Aortic Valve Implantation (“TAVI”) and EndoVascular abdominal Aortic aneurysm Repair (“EVAR”). Although these procedures may often be effective at treating the condition addressed, they often cause injury to the blood vessel in which the large bore vascular access catheter is inserted to gain access for performing the procedure. In fact, vascular injury requiring treatment occurs in as many as 30-40% of large bore vascular procedures, according to some sources. Injury to the blood vessel may include perforation, rupture and/or dissection, which causes blood to flow out of the artery (“extravascular bleeding”), often requiring emergency surgery to repair the damaged blood vessel wall. If not properly treated, such a vascular injury may lead to anemia, hypotension or even death.
[0004] Vascular injury during large bore intravascular procedures is typically caused by the vascular access sheath itself and/or one or more instruments passed through the sheath to perform the procedure. Larger diameter vascular access sheaths are required in a number of catheter-based procedures, such as those mentioned above, where relatively large catheters/instruments must be passed through the sheath. Several other factors may increase the risk of vascular injury, including occlusive disease of the access vessel(s) and tortuosity/angulation of the access vessel(s). Another vascular injury caused by large bore intravascular procedures that can be challenging is the access site itself. Typically, large bore catheterizations create a significantly large arteriotomy, due to a disproportionately large ratio of the diameter of the vascular access catheter to the diameter of the artery in which it is placed. Large arteriotomies may require special management and multiple steps during closure. This may lead to significant blood loss while access closure is attempted.
[0005] Several techniques have been attempted to reduce the incidence of vascular injury in large bore vascular access procedures. For example, preoperative imaging of the blood vessel to be accessed, in the form of CT and MR angiography, may provide the physician with an idea of the anatomy of the vessel. If a particular vessel appears on imaging studies to be relatively tortuous or small, possible adjunctive maneuvers to prevent arterial dissection include pre-dilatation angioplasty of the iliofemoral vessels prior to large bore sheath placement, utilization of smaller access sheaths when possible, stiffer wires to aid in sheath placement and/or use of hydrophobic sheaths. In another attempt at preventing vessel injury, sheath placement may be performed under fluoroscopic guidance, and advancement may be halted when resistance is encountered. Despite the availability of these techniques, vascular injury requiring treatment still occurs in a large percentage of large bore vascular procedures.
[0006] Vascular injuries caused by intravascular procedures are generally quite difficult to diagnose and treat. When an arterial dissection occurs, it often remains undetected until the catheterization procedure is completed and the vascular access sheath is removed. For example, upon removal of the access sheath, large segments of the dissected vessel wall may be released within the vessel. The dissected vessel wall may lead to a breach in the artery wall, a flow-limiting stenosis, or distal embolization. Perforation or rupture of the iliofemoral artery segment may occur from persistent attempts to place large access sheaths in iliac arteries that are too small, too diseased, and/or too tortuous. Here too, a perforation may be likely to remain silent until sheath withdrawal.
[0007] Generally, vascular perforations and dissections caused by large bore vascular procedures allow very little time for the interventionalist to react. Frequently, these vascular injuries are associated with serious clinical sequelae, such as massive internal (retroperitoneal) bleeding, abrupt vessel closure, vital organ injuries, and emergency surgeries. In some cases, an interventionalist may first attempt to repair a vascular injury using an endovascular approach. First, the injury site may be controlled/stabilized with a balloon catheter, in an attempt to seal off the breached vessel wall and/or regain hemodynamic stability in the presence of appropriate resuscitation and transfusion of the patient by the anesthesiologist. Subsequently, endovascular treatment solutions may be attempted, for example if wire access is maintained through the true lumen. This may involve placement of one or more balloons, stents, or covered stents across the dissection/perforation. If the hemorrhage is controlled with these maneuvers and the patient is hemodynamically stabilized, significant reduction in morbidity and mortality may be realized. If attempts at endovascular repair of the vessel fail, emergency surgery is typically performed.
[0008] Presently, vascular injuries and complications occurring during and after large bore intravascular procedures are managed using a contralateral balloon occlusion technique (“CBOT”). CBOT involves accessing the contralateral femoral artery (the femoral artery opposite the one in which the large bore vascular access sheath is placed) with a separate access sheath, and then advancing and maneuvering a series of different guidewires, sheaths and catheters into the injured (ipsilateral) femoral or iliofemoral artery to treat the injury. Eventually, a (pre-sized) standard balloon catheter is advanced into the injured artery, and the balloon is inflated to reduce blood flow into the area of injury, thus stabilizing the injury until a repair procedure can be performed. Typically, CBOT involves at least the following steps: (1) Place a catheter within the contralateral ilofemoral artery (this catheter may already be in place for use in injecting contrast during the intravascular procedure); (2) Advance a thin, hydrophilic guidewire through the catheter and into the vascular access sheath located in the ipsilateral iliofemoral artery; (3) Remove the first catheter from the contralateral iliofemoral artery; (4) Advance a second, longer catheter over the guidewire and into the vascular access sheath; (5) Remove the thin, hydrophilic guidewire; (6) Advance a second, stiffer guidewire through the catheter into the vascular access sheath; (7) In some cases, an addition step at this point may involve increasing the size of the arteriotomy on the contralateral side to accommodate one or more balloon catheter and/or treatment devices for treating arterial trauma on the ipsilateral side; (8) Advance a balloon catheter over the stiffer guidewire into the damaged artery; (9) Inflate the balloon on the catheter to occlude the artery; (10) Advance one or more treatment devices, such as a stent delivery device, to the site of injury and repair the injury.
[0009] As this description suggests, the current CBOT technique requires many steps and exchanges of guidewire and catheters, most of which need to be carefully guided into a vascular access catheter in the opposite (ipsilateral) iliofemoral artery. Thus, the procedure is quite challenging and cumbersome. Although considered the standard of care in the management of vascular complications, the CBOT technique may not provide immediate stabilization of an injured segment, may lack ipsilateral device control, and/or may not provide ready access for additional therapeutics such as stents, other balloons and the like.
[0010] Therefore, in the management of vascular injuries and complications stemming from large bore intravascular procedures, it would be useful to provide a solution for minimizing blood loss and bridging the time to treatment (for example, an endovascular or surgical procedure) while maintaining an access pathway for delivering one or more treatment devices (balloon catheters, stents, etc.) to the injury site. It would also be desirable to provide blood flow occlusion during vascular closure after femoral artery catheterization. Ideally, a device for blood flow occlusion would be compatible with commonly available blood vessel closure devices and techniques, to facilitate blood flow occlusion during closure and occlusion device removal after closure. At least some of these objectives will be met by the embodiments described herein.
SUMMARY
[0011] Example embodiments described herein have several features, no single one of which is indispensable or solely responsible for their desirable attributes. Without limiting the scope of the claims, some of the advantageous features of some embodiments will now be summarized.
[0012] The present application is directed generally to medical devices, and more particularly, to methods and devices for maintaining vascular access and/or minimizing bleeding during percutaneous interventions.
[0013] For example, the methods and devices described herein may allow for simultaneous blood flow occlusion and device exchanges in the iliofemoral segment. In addition or alternatively, the methods and devices may maintain percutaneous vascular access while allowing for simultaneous flow occlusion and device exchanges. Optionally, the methods and devices may be utilized through the same (ipsilateral) interventional access site. The methods and devices may also be compatible with commonly available balloon/stent, and/or vascular closure systems.
[0014] In one aspect, a method of reducing the risk of clinical sequelae to catheter induced vascular injuries may involve: introducing a guide wire into a vascular sheath residing in a blood vessel, the guide wire having a distal end and an inflatable balloon at least 5 cm proximal of the distal end; proximally retracting the vascular sheath while leaving the wire in place; and observing indicia of the presence or absence of a vascular injury caused to the blood vessel by the vascular sheath or a procedural catheter previously advanced through the vascular sheath. If indicia of a vascular injury are observed, the method may further include proximally retracting the guide wire to position the inflatable balloon adjacent the injury and inflating the balloon to reduce blood flow past the injury, while leaving the guide wire in place to provide subsequent access to the injury.
[0015] In some embodiments, prior to the introducing step, the vascular sheath may be used for performing an intravascular procedure, such as but not limited to implantation of an aortic valve (TAVI/TAVR) and abdominal aortic aneurysm repair (EVAR). In some embodiments, observing indicia may involve observing contrast injected into the blood vessel using a radiographic imaging device. In some embodiments, the vascular sheath may have an external diameter at least about 80 percent as large as an internal diameter of the blood vessel. In some embodiments, the vascular sheath may be disposed in a femoral artery, the inflatable balloon may be at least 15 cm proximal of the distal end, and introducing the guide wire may involve advancing a tip of the wire into an aorta.
[0016] In some embodiments, inflating the balloon may involve inflating at a location of the vascular injury. Alternatively, inflating the balloon may involve inflating at a location upstream of the vascular injury. In some embodiments, the method may further include: removing the vascular sheath from the blood vessel; forming at least a partial seal at a puncture site in the blood vessel through which the vascular sheath was removed from the blood vessel; deflating the inflatable balloon of the guide wire; and removing the guide wire from the blood vessel through the seal at the puncture site, where the seal closes around a small hole left in the seal when the guide wire is removed. In some embodiment, the method may further involve introducing a vascular repair device over the guide wire and repairing the vascular injury using the vascular repair device. In some embodiments, the vascular repair device may include a stent deployment catheter, and repairing the vascular injury comprises placing a stent in the blood vessel.
[0017] In another aspect, a method of treating a patient may include: advancing a guide wire into a vascular sheath following an intravascular procedure, the guide wire comprising a distal end and a radially expandable structure spaced at least 5 cm proximally of the distal end; proximally withdrawing the sheath; evaluating the presence of a vascular injury caused by the sheath or a device introduced through the sheath; and if a vascular injury is observed, repositioning the guide wire and expanding the radially expandable structure to stabilize the injury. In some embodiments, the vascular sheath may be located in an iliofemoral artery, and advancing the guide wire may involve advancing the wire through into the vascular sheath from outside the body.
[0018] In one embodiment, the intravascular procedure includes implantation of an aortic valve. In another embodiment, the intravascular procedure includes an abdominal aortic aneurysm repair. In some embodiments, expanding the radially expandable structure may involve inflating a balloon. In some embodiments, expanding the radially expandable structure to stabilize the injury may involve reducing blood flow in an area around the vascular injury.
[0019] In another aspect, a method of treating a patient may involve introducing a guide wire into a blood vessel, the guide wire comprising a distal end and an inflatable balloon spaced at least 5 cm proximally of the balloon, introducing an index procedure catheter over the wire, and conducting an index procedure proximally of the balloon. In some embodiments, the index procedure may include implantation of an aortic valve. In some embodiments, the index procedure may include an abdominal aortic aneurysm repair.
[0020] In another aspect, a method of reducing the risk of clinical sequelae to catheter induced vascular injuries may include introducing a guide wire into a vessel, the guide wire having a distal end and a radially enlargeable structure at least 5 cm proximal of the distal end, advancing a procedure catheter along the wire, and performing a procedure with the procedure catheter, such that if the procedure catheter or an access sheath used introduce the procedure catheter produces a vascular injury, the guide wire can be advanced or retracted to position the radially enlargeable structure adjacent the injury, and the structure can be radially enlarged to control the injury while leaving the guide wire in place to provide subsequent access to the injury. In one embodiment, the procedure catheter may be an over the wire catheter. In one embodiment, the procedure catheter may be a rapid exchange catheter. In one embodiment, the procedure may be a heart valve repair. In one embodiment, the procedure may be a heart valve replacement. In one embodiment, the procedure may be implantation of an abdominal aortic aneurysm graft.
[0021] In some embodiments, if a vascular injury is not observed, the guide wire may be advanced or retracted without radially enlarging the radially enlargeable structure. In some embodiments, the radially enlargeable structure may be an inflatable balloon. Some embodiments may further include the step of evaluating the presence of a vascular perforation using Doppler ultrasound. Some embodiments may further include the step of evaluating the presence of a vascular perforation using contrast injection. In some embodiments, a vascular perforation is observed, the radially enlargeable structure is enlarged to control the injury, and a repair catheter is advanced along the guide wire. In some embodiments, the repair catheter may include a stent delivery catheter. In some embodiments, the repair catheter may include a graft delivery catheter. In some embodiments, a vascular injury is observed, the radially enlargeable structure is enlarged to control the injury, and the injury is thereafter surgically repaired.
[0022] In another aspect, a method of treating a catheter induced vascular injury may involve: advancing an inflatable balloon of a guide wire through a vascular sheath disposed in an iliofemoral artery, where the vascular sheath was used to perform a catheter based intravascular procedure; retracting the vascular sheath proximally; assessing the artery for injury; repositioning the guide wire within the artery; inflating the balloon to occlude the artery; removing an inflation device from the guide wire, wherein the balloon remains inflated after the inflation device is removed; advancing a vascular repair device over a proximal end of the guide wire; performing a repair procedure on the artery, using the repair device; removing the repair device over the guide wire; deflating the balloon using the inflation device; and removing the guide wire from the artery.
[0023] In some embodiments, prior to the advancing step, the vascular sheath is used for performing an intravascular procedure, such as but not limited to implantation of an aortic valve or abdominal aortic aneurysm repair. In some embodiments, observing indicia involves observing contrast injected into the artery using a radiographic imaging device. In some embodiments, the vascular sheath may be disposed in a femoral artery, the inflatable balloon may be at least 15 cm proximal of a distal end of the guide wire, and advancing the guide wire may involve advancing a tip of the wire into an aorta. In some embodiments, inflating the balloon may involve inflating at a location of the vascular injury. In some embodiments, inflating the balloon may involve inflating at a location upstream of the vascular injury.
[0024] In another aspect, a vascular guide wire may include: an elongate tubular body having a proximal end, a distal end and a lumen extending longitudinally through at least part of the body, which may include a proximal portion, a flexible distal tip that is at least about 15 cm long and is more flexible than the proximal portion, and a transition portion between the proximal and distal portions. The guide wire may further include an inflatable balloon disposed on the transition portion and in communication with the lumen and a valve on the proximal portion of the elongate body configured to couple with an inflation device to allow for inflation and deflation of the balloon.
[0025] In some embodiments, the valve may include an axially movable occluder, positioned within the lumen, and the valve may be configured to lock inflation fluid inside the lumen when in a closed position, to allow the inflation device to be removed, thus leaving a hubless proximal end over which one or more devices may be advanced. In some embodiments, the occluder may be movable between a proximal position and a distal position, and the valve may be closed when the occluder is in the distal position. In some embodiments, the distal tip may include a proximal section having a first flexibility and a J-tip at the distal end of the elongate body having a second flexibility that is greater than the first flexibility. In some embodiments, the proximal section may have a length of at least about 15 cm, and the J-tip may have a length of at least about 5 cm. In some embodiments, the distal tip may have a length of at least about 20 cm. In some embodiments, the distal tip may have a length approximately equal to an average length of an iliofemoral artery.
[0026] In some embodiments, the proximal portion may include a tube with a spiral cut along a portion of its length nearer its distal end, and the spiral cut may have decreasing spacing toward the distal end. In some embodiments, the distal tip may include a core wire wrapped in a coil, and the core wire may extend through the transition portion and into the proximal portion. Optionally, some embodiments may further include a coating over the spiral cut to prevent fluid from passing out of the lumen through the cut.
[0027] In another aspect, a vascular guide wire may include an elongate tubular body having a proximal end, a distal end, and a lumen extending longitudinally through at least part of the body. The elongate body may include a proximal section having a first average stiffness, a transition section having a second average stiffness that is less than the first stiffness, and a distal tip having a length of at least about 15 cm and a third average stiffness that is less than the second stiffness. The guide wire may further include an expandable member disposed on the transition section, wherein the expandable member is expandable via fluid advanced through the central lumen of the elongate body.
[0028] In some embodiments, the distal tip may have approximately the same stiffness as the transition section immediately adjacent a distal end of the transition section and may become significantly more flexible toward the distal end of the elongate body. In some embodiments, the guide wire may also include a valve within the tubular body. In some embodiments, the valve may include a locking feature for locking in an inflated configuration to maintain the expandable member in an expanded configuration even after an inflation device is removed from the wire. In some embodiments, the distal tip may include a preformed J-tip such that a curved sidewall of the J-tip rather than the distal end of the elongate body is the leading structure during normal transvascular advance.
[0029] Optionally, the guide wire may also include at least one radiopaque marker for indicating a position of the expandable member. In some embodiments, the expandable member may be an inflatable balloon. In some embodiments, the distal tip may have a length of at least about 20 cm. In some embodiments, the distal tip may have a length approximately equal to an average length of an iliofemoral artery. In some embodiments, the proximal end of the elongate body may be hubless, such that at least one additional device may be passed over the proximal end while the guide wire device is in the patient with the expandable member in an expanded configuration.
[0030] In another aspect, a vascular guide wire system may include a guide wire device and an inflation device. The guide wire device may include an elongate tubular body having a proximal portion, a flexible distal tip that is at least about 15 cm long and is more flexible than the proximal portion, a transition portion between the proximal and distal portions, and a lumen extending longitudinally through at least part of the body. The guide wire device may also include an inflatable balloon disposed on the transition portion and in communication with the lumen and a valve on the proximal portion of the elongate body. The inflation device may be configured to couple with the elongate body to open and close the valve and allow for inflation of the inflatable balloon.
[0031] In some embodiments, the valve may include an axially movable occluder, positioned within the lumen, and the valve may be configured to lock inflation fluid inside the lumen when in a closed position, to allow the inflation device to be removed, thus leaving a hubless proximal end of the elongate body, over which one or more devices may be advanced. Optionally, some embodiments of the system may further include an inflation medium injection device, such as but not limited to a pump. In some embodiment, the distal tip of the guide wire device may be a J-tip and may have a length of at least about 20 cm. In some embodiments, the proximal end of the elongate body may be hubless. In some embodiments, the distal tip of the guide wire device may include a core wire wrapped in a coil, and the core wire may extend through the transition portion and into the proximal portion.
[0032] In another embodiment, the valve provided to lock inflation fluid inside the lumen when in a closed position, can comprise a microvalve assembly. The microvalve assembly can be provided such that it allows the inflatable balloon to be inflated while the valve is in the open position, and upon closing the valve it locks the inflation fluid inside the lumen. The microvalve can be provided with a profile small enough such that the vascular guide wire or elongate body can continue to function as a guide wire. To deflate the balloon, the valve can be re-opened.
[0033] In yet another embodiment, the valve can comprise a micro O-ring that can be constrained on each end by a pair of small sleeves. A movable wire, or piston element, can be integrated with a frictional element and handle that when shifted into the lumen of the guide wire in a distal direction can act as a sealing mechanism. The O-ring can be stationary and the action of the piston shifting into the inner diameter of the O-ring sealing member can cause it to seal and provide a closed state. Shifting the handle of the piston in a proximal direction, partially withdrawing the piston from the lumen of the guide wire can open the valve by removing the piston from the O-ring inner diameter. Alternatively, the O-ring can be attached at the end of the piston and movable together with the piston to block the inflation port or fill ports.
[0034] These and other aspects and embodiments of the invention will be described below in further detail, in relation to the attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0035] FIGS. 1A-1E are diagrammatic illustrations of a femoral artery, iliofemoral segment and aorta portion, showing an exemplary method for controlling blood flow during vascular access closure, according to one embodiment;
[0036] FIGS. 2A-2I are diagrammatic illustrations of a femoral artery, iliofemoral segment and aorta portion, showing an exemplary method for stabilizing vascular injuries and managing blood flow during interventions to treat vascular injuries, according to one embodiment;
[0037] FIG. 3 is a side view of an exemplary guide wire balloon device, along with close-up, cross-sectional views of a distal tip, balloon section and valve section of the device, according to one embodiment;
[0038] FIGS. 4A and 4B are cross-sectional side views of an alternative embodiment of a valve section (fluid regulator/valve), shown in a valve-closed configuration ( FIG. 4A ) and a valve-open configuration ( FIG. 4B ), which may be included in a guide wire device, such as the guide wire device shown in FIG. 3 ;
[0039] FIGS. 5A and 5B are cross-sectional side views of another alternative embodiment of a valve section (fluid regulator/valve), shown in a valve-closed configuration ( FIG. 5A ) and a valve-open configuration ( FIG. 5B ), which may be included in a guide wire device, such as the guide wire device shown in FIG. 3 ;
[0040] FIGS. 6A and 6B are cross-sectional side views of an alternative embodiment of a valve section (fluid regulator/valve), shown in a valve-open configuration ( FIG. 6A ) and a valve-closed configuration ( FIG. 6B ), which may be included in a guide wire device, such as the guide wire device shown in FIG. 3 ;
[0041] FIGS. 7A and 7B are cross-sectional side views of an alternative embodiment of a valve section (fluid regulator/valve), shown in a valve-open configuration ( FIG. 7A ) and a valve-closed configuration ( FIG. 7B ), which may be included in a guide wire device, such as the guide wire device shown in FIG. 3 ;
[0042] FIG. 8 is a side view of a guide wire balloon device, along with close-up, cross-sectional views of a distal tip, balloon section and valve section of the device, according to an alternative embodiment;
[0043] FIGS. 9A-9L illustrate alternative stiffness characteristics of the individual segments of a guide wire device, according to various alternative embodiments;
[0044] FIG. 10 is a diagrammatic illustration of a femoral artery, iliofemoral segment and aorta portion, illustrating the relative length of a portion of a guide wire device, with the device in position across an iliofemoral segment, according to one embodiment;
[0045] FIG. 11 is a diagrammatic illustration of a femoral artery access site and a side view of a portion of a guide wire device passed through an access site in the artery, where the guide wire device has a flexible distal end, extending across a nonlinear path at the vascular access site, according to one embodiment;
[0046] FIG. 12 is a chart illustrating experimental results comparing the stiffness characteristics of a guide wire device according to one embodiment with existing products;
[0047] FIG. 13 shows an angiogram of a guide wire device according to one embodiment, illustrating the device's ability to occlude blood flow in a blood vessel;
[0048] FIGS. 14A and 14B show angiographic images of the guide wire device of FIG. 13 extending from an iliofemoral segment to an aorta;
[0049] FIG. 15 is a perspective view of a guide wire balloon system, including close-up views of an inflation device, a balloon section of a guide wire device, and a core wire and distal tip of the guide wire device, according to one embodiment;
[0050] FIG. 16 is a perspective view of the system of FIG. 15 partially packaged in a kit with other components, according to one embodiment;
[0051] FIG. 17A is a side view of a guide wire device such as that shown in FIG. 15 ;
[0052] FIG. 17B is a side, cross-sectional view of the distal tip of the guide wire device of FIG. 17A ;
[0053] FIGS. 17C and 17D are side, cross-sectional views of the valve section of the guide wire device of FIG. 17A , shown in a valve-closed configuration ( FIG. 17C ) and a valve-open configuration ( FIG. 17D );
[0054] FIGS. 18-25 are side, cross-sectional views of balloon sections of guide wire devices, according to various alternative embodiments;
[0055] FIG. 26A is a perspective view of an inflation device for use with a guide wire balloon device, according to one embodiment;
[0056] FIG. 26B is an exploded view of the inflation device of FIG. 26A ;
[0057] FIGS. 26C-26F are top, perspective, side and end-on views, respectively, of the inflation device of FIG. 26A ;
[0058] FIGS. 27A and 27B are top views of an inflation device and the hands of a user, illustrating a method for using the inflation device, according to one embodiment;
[0059] FIG. 28 is a side view of an exemplary guide wire balloon device, along with close-up, cross-sectional views of a distal tip, balloon section and valve section of the device, according to one embodiment;
[0060] FIGS. 29A and 29B are cross-sectional side views of an alternative embodiment of a valve section (fluid regulator/valve), shown in a valve-closed configuration ( FIG. 29A ) and a valve-open configuration ( FIG. 29B ), which may be included in a guide wire device, such as the guide wire device shown in FIG. 28 ;
[0061] FIG. 30 is a cross-sectional side view of a piston assembly inserted at the proximal end of a guide wire device, such as the guide wire device shown in FIG. 28 ;
[0062] FIG. 31A is a side view of a piston assembly with a split tube attached to a piston of the piston assembly, prior to forming the split tube into a frictional element;
[0063] FIG. 31B is a side view of the piston assembly of FIG. 31A , where the split tube has been formed into the frictional element; and
[0064] FIGS. 32A and 32B are cross-sectional side views of another alternative embodiment of a valve section (fluid regulator/valve), shown in a valve-closed configuration ( FIG. 32A ) and a valve-open configuration ( FIG. 32B ), which may be included in a guide wire device.
DETAILED DESCRIPTION
[0065] Although certain embodiments and examples are disclosed below, inventive subject matter extends beyond the specifically disclosed embodiments to other alternative embodiments and/or uses, and to modifications and equivalents thereof. Thus, the scope of the claims appended hereto is not limited by any of the particular embodiments described below. For example, in any method or process disclosed herein, the acts or operations of the method or process may be performed in any suitable sequence and are not necessarily limited to any particular disclosed sequence. Various operations may be described as multiple discrete operations in turn, in a manner that may be helpful in understanding certain embodiments; however, the order of description should not be construed to imply that these operations are order dependent. Additionally, the structures, systems, and/or devices described herein may be embodied as integrated components or as separate components.
[0066] For purposes of comparing various embodiments, certain aspects and advantages of these embodiments are described. Not necessarily all such aspects or advantages are achieved by any particular embodiment. Thus, for example, various embodiments may be carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other aspects or advantages as may also be taught or suggested herein.
[0067] Referring now to FIGS. 1A-1E , one embodiment of a method for controlling bleeding during vascular closure, for example after femoral artery catheterization, is illustrated. FIG. 1A shows a segment of an arterial pathway, including the iliofemoral artery 100 , the femoral artery 102 , and the aorta 101 . (This and other anatomical drawings are not drawn to scale and are not necessarily anatomically correct but are provided for descriptive, exemplary purposes.) Many of the descriptions herein discuss accessing and treating an iliofemoral artery (or “iliofemoral segement”), which is a length of an artery extending from a portion of a femoral artery to a portion of an iliac artery. These descriptions are for exemplary purposes only, and in various embodiments, other blood vessels may be accessed and/or treated, such as but not limited to femoral arteries, iliac arteries, aortas and the like. For example, using various devices and methods described below, a guide wire balloon catheter device may be advanced into a femoral artery, a distal tip of the device may be passed into the aorta, and the device may then be used to occlude flow within, and provide access to, an iliofemoral artery. Thus, the descriptions below should not be interpreted to limit the scope of the invention to a particular blood vessel.
[0068] FIG. 1B shows a vascular access sheath 110 inserted through a vascular access site in the femoral artery 102 and extending through the iliofemoral segment 100 for conducting any suitable diagnostic and/or therapeutic catheterization procedure. The sheath 110 may have a diameter of 14F, 16F, 18F or the like in some embodiments, or may be smaller or larger in alternative embodiments. Generally, the sheath 110 may be any suitable sheath for performing an intravascular procedure and is placed in the iliofemoral artery 100 to perform the procedure (i.e., prior to the introduction and use of the guide wire device described herein.) The sheath 110 may be introduced in a retrograde orientation, as shown, or alternatively, in some procedures, the sheath 110 and/or other devices herein may be introduced antegrade relative to the patient's blood flow, as appropriate for a given application.
[0069] Referring now to FIG. 1C , upon completion of the catheter-based procedure, and before sheath withdrawal, a guide wire balloon device 120 or system (for example, any of the embodiments described elsewhere herein or in the applications incorporated by reference herein) may be inserted into the sheath 110 such that a tip 121 of the guide wire device 120 , for example, a floppy “J tip,” is positioned past the distal tip 111 of the sheath 110 inside the aorta 101 . The guide wire balloon device 120 may be described herein as an “guide wire,” “guide wire balloon catheter,” “guide wire device” or the like. As described further elsewhere herein, the guide wire device 120 may have a cross-sectional size that allows the sheath 110 to be inserted, withdrawn and/or exchanged over the guide wire shaft (and/or allow secondary devices to be advanced over the device 120 ). Thus, the sheath 110 may be withdrawn (partially or completely) proximally and/or advanced distally over the guide wire device 120 to adjust positioning of the sheath 110 relative to the device 120 .
[0070] As illustrated in FIG. 1D , in a next step, the sheath 110 may be retracted/withdrawn relative to the guide wire device 120 , while maintaining the device 120 in position, to expose a balloon 122 or other expandable member on the guide wire device 120 . The balloon 122 may be positioned and inflated at a desired occlusion site before, during, or after complete withdrawal of the sheath, as shown in FIG. 1D .
[0071] With continuing reference to FIG. 1D , after the sheath 110 has been removed from the femoral artery, the vascular access site may be closed, for example, with a suture/sealant combination 130 , advanced about or otherwise in cooperation with the guide wire device 120 at the site of arteriotomy. Exemplary closure devices and methods that may be delivered over or otherwise in conjunction with the guide wire device 120 (or any of the embodiments herein) are disclosed in U.S. Pat. Nos. 7,316,704, 7,331,979, 7,335,220 and 7,806,856, and U.S. Patent Application Publication Nos. 2007/0231366, 2008/0082122, 2009/0088793, 2009/0254110, 2010/0168789, 2010/0274280 and 2010/0280546. The entire disclosures of these references are expressly incorporated by reference herein.
[0072] As shown in FIG. 1E , next the balloon 122 may be deflated, and the guide wire device 120 may be withdrawn through the closed arteriotomy. In these embodiments, the sealant 130 may be capable of closing the hole left by the guide wire device 120 after withdrawal.
[0073] Referring now to FIGS. 2A-2I , another method is provided for managing vascular complications and/or controlling bleeding during or after trans-femoral catheterization. FIG. 2A again illustrates the femoral artery 102 , iliofemoral artery 100 (or “iliofemoral segment”) and a small portion of the aorta 101 . As shown in FIG. 2B , the method may initially include inserting a vascular access sheath 110 (or “procedure sheath”) into the femoral artery 102 and advancing its distal end 111 into the iliofemoral segment 100 for conducting a catheterization procedure, similar to the previous embodiment. In most embodiments, the vascular access sheath 110 will be used for performing one or more intravascular or transvascular procedures, such as but not limited to EVAR or TAVI (also called transvascular aortic valve replacement, or “TAVR”). Next, as illustrated in FIG. 2C , upon completion of the procedure, and before withdrawing the vascular access sheath 110 , a guide wire balloon device 120 (for example, any of the embodiments described elsewhere herein or in the applications incorporated by reference herein) may be inserted into the procedure sheath 110 , such that a tip 121 of the guide wire device 120 is positioned past the sheath tip 111 inside the aorta 101 (or other body lumen).
[0074] Referring to FIGS. 2D and 2E , the sheath 110 may then be withdrawn, for example, under angiographic guidance, while maintaining the position of the guide wire device 120 in the iliofemoral artery 100 . If sheath withdrawal uncovers a vascular injury, such as dissections 132 (shown in FIG. 2D ) or perforations 134 (shown in FIG. 2E ), expedient catheter management of the injury is possible by the guide wire device 120 , which is positioned in the true lumen of the vessel 100 . As shown in FIG. 2F , as a first step, the balloon 122 may be positioned at the location of the vascular injury 132 and inflated, in an effort to stabilize the vessel wall at the site of injury, and/or to bridge the complication for further treatment options.
[0075] With reference to FIG. 2G , the guide wire device 120 may provide a path for ipsilateral insertion of a treatment device, such as a catheter 134 with a balloon 136 and possibly a stent mounted on the balloon 136 , for treating the vascular injury 132 . In most or all embodiments, the guide wire device 120 may be “hubless,” meaning that once an inflation device (not shown) is removed from the device 120 , one or more instruments may be passed over the proximal end of the guide wire device 120 without having to remove or navigate over a proximal hub. This hubless feature provides a significant advantage in ease of use for passing one or more additional devices to the area of the vascular injury. In other embodiments, alternative or additional treatment devices may be advanced over guide wire device 120 , such as but not limited to any suitable catheter device, such as balloon expandable devices, stent delivery devices, graft delivery devices, radiofrequency or other energy delivery devices or the like. Under such scenarios, the device(s) 134 may be inserted into the target vessel over the guide wire device 120 while the injury is stabilized and bleeding is minimized by the expanded balloon 122 , as shown in FIG. 2G .
[0076] Referring now to FIG. 2H , to facilitate positioning of a treatment device 134 , the balloon 122 of the guide wire device 120 may be deflated and moved as desired within the vessel, for example, to an upstream location, as shown. Optionally, the tip 121 may be positioned past the iliofemoral segment 100 in the aorta 101 at anytime during the procedure, for example, in order to prevent tip-related injury. In such procedures, the floppy tip 121 , which may include the entire length distal to the balloon 122 , may be sufficiently long to extend into the aorta when the balloon 122 is positioned in the iliofemoral segment 100 . For example, in various embodiments, the tip 121 may be at least longer than the average length of the iliofemoral segment 100 , such as at least about 15 cm, more preferably at least about 20 cm, and even more preferably between about 20 cm and about 25 cm.
[0077] In the embodiments described above, the guide wire device 120 and therapeutic device(s) 134 are advanced to the injury site through vasculature on the same side of the patient's body that the procedural vascular access sheath 110 was placed. For the purposes of this application, this side of the patient is referred to as the ipsilateral side of a patient. In other words, in this application, “ipsilateral” refers to the side of the patient's body on which the main access was achieved for performing a given endovascular procedure. For example, the “ipsilateral femoral artery” or “ipsilateral iliofemoral artery” will generally be the artery in which a vascular access sheath 110 (or any other access device) is placed for advancing instruments to perform the intravascular procedure (TAVI, EVAR, etc.). “Contralateral” refers to the opposite side of the patient, relative to the procedure access side. In this regard, “ipsilateral” and “contralateral” relate to the side on which access is gained to perform the main procedure and do not relate to where the physician stands to perform the procedure. In any case, various embodiments of the methods and devices described herein may be used exclusively via an ipsilateral approach, exclusively via a contralateral approach, or interchangeably via an ipsilateral or contralateral approach.
[0078] The method just described in relation to FIGS. 2A-2I may have a number of advantages over the prior art contralateral balloon occlusion technique (CBOT). One advantage, for example, is that the guide wire balloon device 120 will typically be located very close to the vascular injury 132 , 134 when the vascular sheath 110 is withdrawn. Thus, the balloon 122 may be inflated quickly within the iliofemoral artery 100 , aorta 101 or femoral after 102 , perhaps after minor positional adjustments, to quickly occlude the vessel and stabilize the injury 132 , 134 while treatment options are being assessed and prepared. Another potential advantage of the method described above is that only one combined guide wire balloon device 120 is needed to stop blood flow/stabilize the injury 132 , 134 and to provide a path along which treatment device(s) 134 may be advanced into the vessel. In other words, the method does not require multiple different guidewires, guide catheters, introducer sheaths and the like, nor does it require difficult threading of a guidewire into a contralaterally placed sheath. In general, therefore, the described method may be easier and quicker to perform, thus facilitating a quicker and more effective vascular repair.
[0079] FIG. 3 illustrates one embodiment of a guide wire device 300 for performing the various procedures described herein, such as occluding an artery to stop blood flow past a vascular injury and to provide a path for delivering one or more treatment devices to the injury site. Generally, the guide wire device 300 may include a hollow guide wire body having a central lumen 320 , an occlusion balloon 302 (or other expandable member) attached to or otherwise carried on a distal end of the guide wire 300 adjacent a distal tip of the guide wire 300 , and a hubless extracorporeal or proximal end 303 including a valve with an inflation port 306 in communication with the lumen 320 and a balloon inflation port 305 .
[0080] The guide wire device 300 may have dimensions and/or characteristics similar to conventional guide wires. For example, the guide wire device 300 may allow for introduction of other devices, such as catheters or other tubular devices carrying therapeutic and/or diagnostic elements (for example stents, covered stents, stent-grafts, balloons, etc.) In certain embodiments, the guide wire device 300 (including the balloon 302 in a collapsed state) may be sized to be received in and/or to occlude an arterial or other body lumen, for example, sized between about 3 mm and about 15 mm in some embodiments and in other embodiments as large as about 30-40 mm. The guide wire device 300 may also have a sufficient working length to allow introduction of other devices over the guide wire shaft.
[0081] The entire length or the distal end of the guide wire device may be made of compliant material that provides a flexible shape and/or accommodates the distal end conforming to the target lumen geometry. Alternatively, the proximal end 303 may be rigid, semi-rigid, or simply stiffer than the distal end to facilitate advancement of the guide wire device 300 from the proximal end 303 .
[0082] In some embodiments, the central lumen 320 of the guide wire 300 may communicate with the external surface or environment of the device through a series of valves (or other flow regulators) for example, within or on the proximal end 303 of the guide wire device 300 .
[0083] In some embodiments, the deflated balloon 302 may have an overall low profile substantially similar to the guide wire shaft dimension, for example, such that at least the distal end has a substantially uniform diameter and/or the entire length of the guide wire device 300 has a substantially uniform diameter.
[0084] In certain embodiments, the proximal end 303 of the guide wire shaft may be attached to a detachable inflation unit for balloon 302 inflation/deflation. The inflation unit may be sealingly attached around or otherwise to the balloon shaft to provide inflation.
[0085] Some embodiments may include a fluid regulation system, for example, within the proximal end 303 of the guide wire shaft, that maintains inflation/deflation state during operation, for example, when the inflation unit has been utilized to inflate or deflate the balloon 302 and then removed. The fluid regulation system may include a plurality of fluid regulators that are serially installed in order to maintain the balloon 302 in an inflation state, for example, in case of failure of an individual fluid regulator (for example, as a result of balloon catheter manipulation). In one embodiment, the fluid regulator system may include an internal fluid regulator and an external fluid regulator, which are operatively coupled such that opening the internal fluid regulator may cause the external fluid regulator to open as well. The fluid regulation system may also include one or more mechanisms designed to automatically lock at least one fluid regulator. In certain embodiments, the fluid regulator system may also include one or more protective features to prevent or minimize accidental manipulation, kinking etc., which may adversely affect inflation or deflation status. For example, one or more protective sleeves, caps, segments of enhanced stiffness, locking mechanisms, etc. (not shown) may be provided.
[0086] In one embodiment, the guide wire shaft may be configured to accept parts that enable extension of the guide wire shaft. For example, a shaft extension mechanism may be connected to the fluid regulator system in an effort to simplify overall design.
[0087] In certain embodiments, the guide wire device 300 may be compatible with vascular closure devices, for example, utilizing sutures, clips, and other implants, etc. The guide wire device 300 may also include one or more radiographic markers, for example, on the distal end adjacent to the balloon 302 , to aid radiographic positioning.
[0088] FIG. 3 shows an exemplary embodiment of a guide wire balloon device or system 300 that includes a guide wire shaft or other outer tubular member including a proximal end 303 , a distal end terminating in a substantially non traumatic distal tip 301 , and a balloon or other expandable member 302 carried on the distal end. The balloon 302 may be formed from a soft membrane 304 , for example, to provide a compliant balloon. The balloon 302 communicates with an internal guide wire lumen 320 of the guide wire shaft, for example, via one or more inflation ports 305 in a side wall of the tubular member. Optionally, an internal wire may be provided within the guide wire shaft, for example, within the lumen 320 , to stiffen, straighten, or otherwise support the distal end or the entire length of the guide wire shaft. The internal wire may be smaller than the lumen 320 , as shown, for example, to accommodate fluid delivery through the lumen 320 around the internal wire. Optionally, the distal tip 301 may include a “J” tip and/or other features (not shown) beyond the balloon 302 , similar to conventional guide wires, if desired.
[0089] The proximal (extra-corporeal) end 303 of the guide wire device 120 may be connected to an inflation device (not shown) for balloon inflation and deflation. In addition, the proximal end 303 may have an integrated flow regulator (valve) system designed to maintain balloon 302 inflation/deflation state, for example, when inflation device is disconnected, such as the embodiments described elsewhere herein and/or in the applications incorporated by reference herein.
[0090] Turning to FIGS. 4A and 4B , an exemplary embodiment of a fluid regulator (valve) system is shown that includes an internal piston 309 that may be directed to sealingly engage and disengage an internal valve 307 within the proximal end 303 of the guide wire shaft, for example, when piston shaft 308 is moved axially relative to the guide wire shaft. For example, as shown in FIG. 4A , the piston shaft 308 may be advanced distally until the piston 309 engages the valve 307 in a distal position. Thus, in the distal position, the lumen 320 of the guide wire shaft may be substantially sealed, for example, after delivering sufficient fluid into the lumen 320 to inflate the balloon 302 . Conversely, as shown in FIG. 4B , the piston shaft 308 may be retracted proximally until the piston 309 reaches a proximal position proximal to an outlet or side port 306 in a side wall of the proximal end 303 of the tubular member. The internal lumen 320 may communicate with the external environment adjacent the proximal end 303 through the outlet 306 when the piston shaft 308 is retracted to the proximal position such that fluid may be delivered into or evacuated from the lumen 320 , for example, to inflate or deflate the balloon 302 (not shown). Optionally, a low profile plunger (not shown) may be provided on the proximal end of the piston shaft 308 outside the proximal end of the guide wire shaft to facilitate actuation of the valve system. Alternatively, a cap (not shown) similar to other embodiments herein may be provided on the proximal end of the guide wire shaft that is coupled to the piston shaft 308 . The cap may have a profile small enough to accommodate advancing supplementary devices (not shown) over the cap onto the guide wire shaft. For example, the proximal end of the guide wire shaft may be smaller than the adjacent length of the guide wire shaft such that the cap provides a substantially uniform outer diameter (“O.D.”) on the guide wire device.
[0091] Turning to FIGS. 5A and 5B another embodiment of a fluid regulator (valve) system is shown that may be provided on the proximal end 303 of a guide wire device, such as device 300 described above. In this embodiment, the internal piston 308 is driven by a spring 310 , for example, a tension spring, which, in a substantially relaxed or relatively lower energy position ( FIG. 5A ) maintains a substantially sealed and/or closed fluid regulator (valve) system. As shown in FIG. 5B , when the piston 308 is moved distally relative to the guide wire shaft, the internal valve 307 may be opened to allow communication between the internal lumen 320 and the external environment of the guide wire device through outlet or side port 306 . When the piston shaft is advanced distally to open the valve 307 , the spring 310 may be subjected to increased tension such that, when the piston shaft is released, the piston shaft may resiliently retract proximally to engage the piston 308 with the valve 307 to automatically seal the lumen 320 , for example, after inflating or deflating the balloon (not shown), similar to the previous embodiments.
[0092] FIGS. 6A and 6B show yet another embodiment of a fluid regulator (valve) system that may be provided on a guide wire device, such as any of the embodiments herein, whereby an external cap 312 covers the outlet or side port 306 that communicates between the guide wire internal lumen 320 and the external environment of the guide wire device 300 . The cap 312 may be moved relative to the outlet 306 , for example, between a proximal position (shown in FIG. 6A ) and a distal position (shown in FIG. 6B ) to open and substantially seal the outlet 306 , for example, to allow fluid to be delivered into and evacuated from the lumen 320 , similar to the previous embodiments.
[0093] Turning to FIGS. 7A and 7B , still another embodiment of a fluid regulator (valve) system is shown that may be provided on a balloon guide wire device. Unlike the previous embodiments, the system includes an internal valve element 307 and an external valve element 306 , which are operatively (serially) connected such that a single actuation step may open both valves (as shown in FIG. 7A ) or close them (as shown in FIG. 7B ). Such a combination of valves may assure that flow within wire's internal lumen 320 is controlled to maintain a desired balloon inflation state.
[0094] In certain embodiments, devices and methods described herein may be compatible with existing devices and work-flow, for example, such that the guide wire device may be the last device to be removed from the target artery. Therapeutic device exchanges may be possible while vascular complications are stabilized endovascularly with a balloon. This may be especially significant, for example, if bleeding occurs at vascular segments that are inaccessible for manual compression (for example, the iliac artery, the proximal femoral artery, specific patient anatomy, etc.).
[0095] In certain clinical scenarios, there might be a need for the guide wire device to be introduced before or during sheath advancement, i.e. through devices with true wire lumens. Therefore, in some embodiments, the guide wire device may have a uniform diameter over the entire length including the inflatable segment and the distal tip.
[0096] The devices and methods described herein may also ensure that access to the true lumen of the target vessel is maintained, when vascular complications are anticipated, but before they are encountered.
[0097] In some embodiments, the devices and methods described herein may facilitate an ipsilateral approach, for example, for better device control and improved blood loss management.
[0098] In certain clinical scenarios, it may be necessary to obtain angiographic guidance during insertion/withdrawal/maneuver of the guide wire device. Therefore, the guide wire device could incorporate mechanisms allowing for contrast injection at or close to the distal tip of the device. Such mechanisms may include channels, valves, and orifices for contrast injection. Alternatively, a custom sheath could be used in conjunction with the guide wire device. Such a custom sheath may be sufficiently dimensioned for housing the guide wire device and allowing for simultaneous contrast flow. The custom sheath may be equipped with a contrast injection port and an extracorporeal valve that prevents contrast back-flow during injection.
[0099] In special clinical scenarios, it may also be useful to assess intravascular pressure, flow, temperature, general morphology, or other properties of the anatomy encountered, for example, to interrogate a special condition beyond angiography. In one embodiment, the guide wire device or system may include elements providing physiological or image data during operation. These elements may include one or more pressure, flow and/or temperature sensors, and/or ultrasound, light, infrared, or other imaging elements. Additionally, one or more features may be provided for assessing intravascular dimensions, including balloon inflation dimension and/or pressure, for example, for estimating vessel sizes, and/or for targeting a specific inflation threshold.
[0100] The devices and systems herein may also have characteristics that allow it to be integrated into a robotic vascular surgery environment, such as the DaVinci system, the Zeus System, the Sensei system, etc.
[0101] In special scenarios, additional treatment to a body lumen or other target segment may be needed beyond balloon inflation. In one embodiment, the system may provide capabilities of local drug or agent or energy delivery through the guide wire system, for example, more desirably through the balloon.
[0102] In special scenarios, it may also be useful to provide a source of therapeutic and/or diagnostic agents, for example, including one or more devices for injection of agents about the target treatment area. For example, the system may include a syringe, pump, or other source for intravascular injection of agents. Such guide wire devices may include an extracorporeal injection port in the proximal end, an injection channel or other lumen, and/or a distal agent release port located in proximity to the balloon.
[0103] In certain clinical scenarios, the best therapy option is endovascular stent implantation. The guide wire device may, thus, incorporate a stent delivery system that is readily available for treatment or in anticipation of vascular injuries.
[0104] The guide wire device may integrate additional lumens for introduction of therapeutic/diagnostic agents/devices. Alternatively, the guide wire system may be provided with a larger sheath that can be introduced over the wire, thereby forming a channel around the external surface of the wire.
[0105] In cases where prolonged flow occlusion is desired, it may be useful to provide simultaneous occlusion of a target region, and perfusion of distal regions. Therefore, the guide wire device or system may include tissue perfusion across the balloon occlusion area. Such features may include perfusion channels in the shaft or balloon, for example, with appropriate ports, valves, and/or flow drivers.
[0106] In special clinical scenarios, it may be useful to isolate a specified segment of a body lumen for diagnostic or treatment purposes. In one embodiment, the guide wire system can be combined with a standard balloon catheter to create a double-balloon catheter system that is capable of isolating a targeted vessel or other bodily passages.
[0107] In certain embodiments, the balloon may provide an anchoring mechanism for the guide wire device, for example, such that over-the-wire device insertion is facilitated.
[0108] In certain embodiments, the occlusion balloon may be conforming to the lumen shape, and may grow axially/longitudinally during inflation. The balloon could exhibit varying wall thicknesses to provide preferential inflation shape. For example, thinner sections inflate first followed by thicker sections as the thin walled portions contact the vessel wall. The balloon could be corrugated by thicker wall sections or Kevlar inflation restrictions to mitigate pressure on the vessel wall.
[0109] In some scenarios, balloon occlusion/inflation is required over long vascular segments. One embodiment could incorporate a device shaft with multiple balloon units that collectively cover a longer vascular segment. The balloon units could be collectively or individually connected to the same/multiple inflation system(s).
[0110] In certain clinical scenarios, balloon dilatation might be required. The guide wire balloon device could incorporate a balloon that fulfills occlusion and dilatation function.
[0111] In one embodiment, the guide wire device could be a closed system with balloon inflation agent stored inside a sealed tubing system. Collapse (or expansion) of the internal lumen of the tubing system would move the fluid into (or away) from the balloon thereby causing balloon inflation (or deflation). This embodiment foresees a tubing system that is not in communication with the external surface and has a pre-installed balloon inflation agent.
[0112] In special clinical scenarios, it may be desirable to have a system for facilitating device insertion through tortuous vascular segments. For example, it might be desirable to have a guide wire device or system that includes a flexible tip designed for retrograde insertion and a stiffer shaft proximal to the tip designed for facilitating over-the-wire device insertion through tortuous segments.
[0113] In certain clinical scenarios, vessel tortuosity may require straightening in order to ease device (sheath) insertion/retraction. The guide wire device could have a stiff shaft capable of non-traumatic straightening originally tortuous vessel. The stiffness could vary along the length. The distal section should be flexible and atraumatic.
[0114] In certain clinical scenarios, vessel tortuosity may require intravascular shape change of the distal tip. The proposed system may integrate steerability mechanisms that allow for temporary shape change of individual segments of the device.
[0115] Referring now to FIG. 8 , in certain clinical scenarios, the target treatment segment may be rigid and/or tortuous and may not respond to straightening attempts. Therefore, it would desirable for the balloon to adapt to vessel tortuosity. In one embodiment, the inflatable segment (i.e., the portion of the device 300 along which the balloon 302 is mounted) may include a more flexible, distal segment 340 (or joint), which allows for the inflatable segment to bend and provide flexibility, and a less flexible, proximal segment 330 . The flexible segment 340 will not impact the balloon inflation functionality.
[0116] Referring now to FIGS. 9A-9L , in certain clinical scenarios, insertion or advancement of the guide wire device requires a minimum of catheter shaft back-bone support (stiffness). This guide wire characteristic is required for segments of the guide wire device such as the device shaft and the proximal part of the distal tip. FIGS. 9A-9L illustrate the stiffness characteristics of the balloon segment 212 a - 212 l relative to the stiffness proximal and distal to the balloon segment 212 a - 212 l , according to various alternative embodiments of the guide wire device. The stiffness/flexibility along each embodiment is designated, from a proximal end 205 a - 205 l to a distal end 219 a - 219 l . In the graphs, the upward direction designates more stiffness (i.e., less flexibility), and the lower direction designates less stiffness (i.e., more flexibility). In all the embodiments shown, the balloon segment 212 a - 212 l may be described as a transition zone or transition segment between a proximal portion and a distal portion. Also, in all embodiments, there is a drop-off in stiffness (increased flexibility) in the balloon segment 212 a - 212 l relative to the proximal portion. In some embodiments, such as those shown in FIGS. 9A-9D and 9 G- 9 J, flexibility is greater in the balloon segments 212 a - 212 d , 212 g - 212 j of the guide wire devices than in the areas of the devices immediately proximal and distal to the balloon segments 212 a - 212 d , 212 g - 212 j . In alternative embodiments, such as those shown in FIGS. 9E , 9 F, 9 K and 9 L, flexibility is greater in the balloon segments 212 e , 212 f , 212 k , 212 l of the guide wire devices than in the areas of the devices immediately proximal to the balloon segments 212 e , 212 f , 212 k , 212 l , but the portions of the devices immediately distal to the balloon segments 212 e , 212 f , 212 k , 212 l are either as flexible as, or more flexible than, the balloon segments 212 e , 212 f , 212 k , 212 l . In other alternative embodiments, other flexibility profiles may be possible. In general, however, it may be advantageous to have a balloon segment 212 a - 212 l of a guide wire device that is positioned between a relatively proximal portion and a relatively stiff distal section, where the balloon segment 212 a - 212 l is more flexible than at least the proximal portion.
[0117] In some embodiments, the removable inflation handle may integrate a torque system that provides torqueing of the guide wire device during operation if desired.
[0118] Referring now to FIG. 10 , in certain clinical scenarios, it is necessary to provide occlusion at the level of the femoral arteriotomy 900 , for example with an inflatable occlusion balloon 302 of a guide wire balloon device 300 , while maintaining position of the distal tip 301 of the device 300 in the aorta 101 . It is therefore desirable for the distal end 311 of the device 300 to be of sufficient length to extend through the iliofemoral 100 segment and be safely positioned (during femoral occlusion) in the aorta 101 , as shown in FIG. 10 . In one embodiment of the guide wire device 300 , the outer diameter of the device 300 may be between about 0.014 and about 0.038 inches. In one embodiment, the length of the distal tip 311 of the device 300 may be between about 20 cm and about 50 cm. Optionally, the distal tip 311 may include a J-tip 301 , as shown, and/or other features (not shown) beyond the balloon 302 , similar to conventional guide wires, if desired.
[0119] As shown in FIG. 11 , in certain embodiments, a distal portion and/or balloon portion 123 of the guide wire device 120 may be capable of bending at sites of procedural bends such as the site of percutaneous catheter insertion. The embodiment shown in FIG. 11 may have a similar “flexibility profile” to those shown in FIGS. 9A-9E , where the portion of the device 120 between the proximal and distal ends of the balloon 122 is more flexible than the shaft of the device 120 immediately proximal and immediately distal to the balloon.
[0120] Referring now to FIG. 11 , several catheter characteristics such as pushability, trackability, and adaptability to vessel tortuosities are directly related to stiffness patterns of the catheter along its shaft. To determine the appropriate stiffness patterns for the guide wire device described herein, the following experiment was performed. The device disclosed herein was compared to the Guardwire balloon system (Medtronic PercuSurge, 0.014″) and the Guideright guide wire (St. Jude, 0.038″). Each device was inserted into a catheter fixture, and the region of interest was aligned with the fixture. After the Instron was calibrated with regard to push force, deflection, and position, the Instron was advanced to cause a 5 mm deflection at the region of interest. Deflection force (LbF, N) and position of deflection (distance from inflatable segment) were recorded. The procedure was then repeated for each additional region of interest. The experimental results are illustrated in FIG. 12 , where the solid line 910 represents the flexibility profile of the exemplary embodiment of the device 120 described herein, the dashed line 912 represents the profile of the Guardwire device, and the dashed line 914 represents the profile of the Guideright device.
[0121] Two catheters, the guide wire device disclosed herein and Guardwire, showed comparable stiffness profiles at the distal tip. The guide wire device, however, showed a different stiffness profile marked by the segmental decrease in stiffness at the balloon segment (position 0) relative to the proximal catheter shaft and the distal tip. This functionality lends a special flexibility feature to the balloon and allows for balloon occlusion at sites of significant tortuosity (where complications are expected), and/or at sites of procedure induced bends (such as transitions from tissue tract into arteriotomy).
[0122] Referring now to FIGS. 13 , 14 A and 14 B, the utility of the guide wire device was successfully tested in the sheep and showed that the intended design of decreased stiffness at the balloon segment allowed for balloon occlusion at sites of significant tortuosity (where complications are expected), and/or at sites of procedure induced bends (such as transitions from tissue tract into arteriotomy). FIG. 13 shows an angiogram of the sheep femoral artery at the site of 18Fr arteriotomy, showing the guide wire device's ability to occlude blood (contrast) flow at the site of percutaneous catheter insertion (arteriotomy). FIG. 14B is an angiographic image showing a clinical scenario where an occlusion at the femoral arteriotomy is required. In this scenario, as shown in FIG. 14A , it would be desirable for the J-tip of the distal tip to be of sufficient length to extend through the iliofemoral segment and be safely positioned (during femoral occlusion) in the aorta.
[0123] Referring now to FIG. 15 , in another embodiment, a guide wire balloon system 200 (or “guide wire system”) for providing blood vessel occlusion, blood vessel injury stabilization and/or a device along which one or more treatment devices may be introduced during or after a large bore or other intravascular procedure may include a guide wire device 202 (or “guide wire balloon device”) and an inflation device 222 . Optionally, the system 200 may also include an inflation medium container/injection device (not shown), such as but not limited to a syringe, a pump or the like. The guide wire device 202 extends from a hubless proximal end 205 to a distal end 219 and includes an expandable member such as an inflatable balloon 220 closer to the distal end 219 than the proximal end 205 . The guide wire device 202 may be described as having a valve portion 204 (or “proximal portion”), a middle portion 210 , a balloon portion 212 (or “transition portion”, “transition section” or “transition zone”) and a flexible tip 216 (or “J-tip,” “distal tip” or “distal portion”). These designations of the various portions of the guide wire device 202 are made for descriptive purposes only and do not necessarily connote specific demarcations or mechanical differences between the various portions, although in some embodiments, the various portions may have one or more unique characteristics.
[0124] The guide wire device 202 may further include a shaft 206 that extends from the valve portion 204 of the guide wire device 202 to at least a proximal end of the balloon 220 . In one embodiment, the shaft 206 may be a hypotube, made of Nitinol, stainless steel, or some other metal, and may include a spiral cut 211 along part of its length to increase flexibility, as will be described in greater detail below. Inside the shaft 206 , within the valve portion 204 , there may reside an inflation hypotube 207 (or “inner tube”) with an inflation port 209 , through which inflation fluid may be introduced. A valve cap 203 may be slidably disposed over the proximal end of the inflation hypotube 207 , such that it may be moved proximally and distally to close and open, respectively, the inflation port 209 . As best seen in the bottom magnified view of FIG. 15 , a core wire 208 may be disposed within the shaft 206 along at least part of the middle portion 210 and may extend through the balloon portion 212 and in some embodiments through at least part of the distal tip portion 216 . A coil 214 may be wrapped around part of the core wire 208 and may also extend beyond the core wire 208 to the extreme distal end 219 . Various aspects and features of the shaft 206 , inflation hypotube 207 , core wire 208 , coil 214 , etc. will be described in further detail below.
[0125] The inflation device 222 , which is also described in more detail below, may generally include a handle 224 , a wire lumen 226 for inserting the guide wire device 202 , and a locking inflation port 228 . The handle 224 may be movable from a first position in which the guide wire device 202 may be inserted into the lumen 226 to a second position in which the handle 224 locks onto the shaft 206 and the valve cap 203 . The handle may also be moveable from a valve-open position, in which inflation fluid may be passed into the inflation port 209 of the guide wire device 202 , to a valve-closed position, in which the inflation fluid is trapped inside the balloon 220 and guide wire device 202 . These positions and other aspects of a method for using the inflation device 222 will be described further below.
[0126] In one embodiment, the guide wire device 202 may have varying amounts of stiffness along its length, typically being stiffest at the proximal end 205 and most flexible at the distal end 219 . The proximal/valve portion 204 and a proximal portion of the middle portion 210 of the guide wire device 202 are typically the stiffest portions of the device and will have sufficient stiffness to allow the device 202 to be advanced through a sheath and into a blood vessel, typically against the direction of blood flow (i.e., retrograde advancement). Along the middle portion 210 , the device 202 may be relatively stiff at a most proximal end and quite flexible at a distal end (within, or adjacent the proximal end of, the balloon 220 ). This change in stiffness/flexibility may be achieved using any of a number of suitable mechanical means. In the embodiment shown, for example, the shaft 206 includes a spiral cut 211 along its length, where the spacing between the cuts becomes gradually less along the middle portion 210 from proximal to distal. In other words, the “threads” of the spiral cut are closer together distally. In alternative embodiments, increasing flexibility of the shaft 206 from proximal to distal may be achieved by other means, such gradually thinning the wall thickness of the shaft, using different materials along the length of the shaft or the like.
[0127] In the embodiment of FIG. 15 , the spiral cut 211 may be configured such that the shaft 206 has a relatively constant stiffness along a the valve portion 204 and a proximal part of the middle portion 210 . As the shaft 206 approaches the proximal end of the balloon 220 , the stiffness may fall off abruptly. In other words, the stiff shaft 206 has a significant drop-off in stiffness immediately proximal to the balloon 220 . This type of stiffness/flexibility profile is in direct contrast to the typical prior art balloon catheter, which simply becomes more flexible at a gradual, consistent rate over its length. The unique stiffness profile of the guide wire device 202 may be advantageous, because maintaining significant stiffness along most of a proximal length of the device 202 provides for enhanced pushability against blood flow, while a significantly more flexible portion immediately proximal to, within, and distal to the balloon 220 will help to prevent injury to the vessel through which the device 202 is being advanced. A stiffer proximal portion 204 and middle portion 210 may also help temporarily straighten out a tortuous blood vessel, which may facilitate stabilizing and/or treating an injury in the vessel.
[0128] The top portion of FIG. 15 is a close up of the balloon section 212 of the guide wire device 202 , with the balloon 220 removed. In this embodiment, the shaft 206 extends into a portion of the balloon section 212 , with the spiral cut getting tighter, and then ends, leaving a small portion of the core wire 208 exposed. Inflation fluid exits from the distal end of the shaft 206 to inflate the balloon 220 . The shaft 206 thus forms an inflation lumen (not visible in FIG. 15 ), and in the embodiment with the spiral cut 211 , a coating or sleeve may be used to seal the shaft 206 to prevent inflation fluid from escaping the shaft 206 through the spiral cut 211 . For example, a polymeric coating may be used, such as a shrink wrap coating, sprayed-on coating, dip coating, or the like. In alternative embodiments, the shaft 206 may end at the proximal end of the balloon 206 or may continue through the entire length of the balloon 220 and include one or more inflation ports in its sidewall. A distal portion of the core wire 208 is wrapped by the core wire 214 . In these or other alternative embodiments, core wire 214 may stop at a distal end of the balloon 220 or alternatively extend all the way through the balloon 220 . A number of various embodiments of the balloon section 212 will be described below in greater detail.
[0129] Referring now to the bottom close-up of FIG. 15 , the core wire 208 may, in some embodiments, have a varying diameter at one or more points along its length. In alternative embodiments, it may have a continuous diameter. In the embodiment shown, for example, the core wire 208 has a relatively small diameter proximally, widens to a wider diameter, widens again to a widest diameter, and contracts gradually to a smallest diameter the flexible, J-tip portion 216 . As will be described in greater detail below, the proximal end of the core wire 208 (not visible in FIG. 15 ) may also be widened, flattened or otherwise shaped to facilitate attaching the proximal end to an inner wall of the shaft 206 via gluing, welding, soldering or the like. The widest diameter section of the core wire 208 , in this embodiment, is located where the distal end of the balloon 220 is mounted onto the core wire 208 . This widest portion thus helps provide strength at an area of stress of the device 202 . In some embodiments, the proximal end of the core wire 208 is attached to an inner surface of the shaft 206 by any suitable means, such as by welding, soldering, gluing or the like. In some embodiments, the attachment point of the core wire 208 to the shaft 206 is proximal to the area along the shaft 206 where the spiral cut 211 begins. Alternatively, the core wire 208 may be attached at any other suitable location.
[0130] As illustrated in the bottom close-up of FIG. 15 , in one embodiment, the diameter of the core wire 208 gets smaller and smaller distally along the length of the flexible J-tip portion 216 , thus forming the most flexible, J-curved, distal portion of the guide wire device 202 . In alternative embodiments, the core wire 208 may end proximal to the extreme distal end 219 of the guide wire device 202 , and the coil 214 may continue to the distal end 219 . In other alternative embodiments, the distal tip 216 may be straight, may include two core wires 208 , may include more than two core wires 208 , may be straightenable and/or the like. In the embodiment shown, the core wire includes a flat portion through the curve of the J-shape of the tip 216 and is attached to the coil 214 at the distal end 219 via a weld (or “weld ball”). The distal, curved portion of the J-tip is designed to be atraumatic to blood vessels through which it is advanced, due to its flexibility and shape.
[0131] The distal J-tip 216 of the guide wire device 202 may include special properties and/or features allowing for retrograde (against blood flow) insertion, maneuvering, and/or placement. For example, the “J-tip” shape of the distal tip 216 allows it to be advanced against blood flow without accidentally advancing into and damaging an arterial wall. Additionally, the distal tip 216 has a proximal portion through which the core wire 208 extends and a distal portion that is more flexible and includes only the coil 214 . This provides for a slightly stiffer (though still relatively flexible) proximal portion of distal tip 216 and a more flexible (or “floppy”) distal portion of distal tip 216 , thus providing sufficient pushability while remaining atraumatic. The extreme distal end 219 may also have a blunt, atraumatic configuration, as shown. In various embodiments, the distal tip 216 may also include a tip configuration, flexibility, radiopacity, rail support, core material, coating, and/or extension characteristics that enhance its function. Alternatively or in addition, device length considerations and/or overall shaft stiffness may be modified accordingly.
[0132] The core wire 208 , the shaft 206 and the coil 214 may be made of any of a number of suitable materials, including but not limited to stainless steel, Nitinol, other metals and/or polymers. Each of these components may also have any suitable size and dimensions. For example, in one embodiment, the shaft 206 has an outer diameter of approximately 0.035 inches (approximately 0.9 mm). The guide wire device 202 may also have any suitable overall length as well as lengths of its various parts. Generally, the distal tip 216 will have a length that allows it to extend into an aorta when the balloon is inflated anywhere within an iliofemoral artery. In other words, the distal tip 216 may be at least approximately as long as the average iliofemoral artery. In various embodiments, for example, the distal tip 216 (measured from the distal end 219 of the device 202 to a distal end of the balloon 220 ) may be at least about 15 cm long, and more preferably at least about 20 cm long, and even more preferably between about 20 cm and about 25 cm long, or in one embodiment about 23 cm long. In various embodiments, the balloon section 212 of the device 202 may have a length of between about 10 mm and about 15 mm, or in one embodiment about 12 mm. In various embodiment, the middle section 210 of the device 202 may have a length of between about 70 cm and about 90 cm, and more preferably between about 75 cm and about 85 cm, or in one embodiment about 80 cm. And finally, in some embodiments, the valve section 204 may have a length of between about 10 cm and about 3 mm, or in one embodiment about 5 cm. Therefore, in some embodiments, the overall length of the device 202 might be between about 85 cm and about 125 cm, and more preferably between about 95 and about 115 cm, and even more preferably between about 105 cm and about 110 cm. Of course, other lengths for the various sections and for the device 202 overall are possible. For example, in some embodiments, the distal tip 216 may be longer than 25 cm, and in various embodiments, the overall length of the guide wire device 202 may range from may be longer than 115 cm. It may be advantageous, however, for ease of use and handling, to give the guide wire device 202 an overall length that is shorter than most currently available catheter devices. For an ipsilateral approach, the device 202 should generally have a length such that it is possible for the proximal portion 204 to extend at least partially out of the patient with the balloon 220 positioned within the iliofemoral artery and the distal end 219 residing in the aorta.
[0133] The balloon 220 of the guide wire balloon device 202 is generally a compliant balloon made of any suitable polymeric material, such as polyethylene terephthalate (PET), nylon, polytetrafluoroethylene (PTFE) or the like. The balloon 220 may be inflatable to any suitable diameter outside and inside the body. In one embodiment, for example, the balloon 220 may be inflatable within a blood vessel to a diameter of between about 6 mm and about 12 mm. In alternative embodiments, the balloon 220 may be semi-compliant or noncompliant. In some embodiments, the balloon 220 and/or portions of the device 202 immediately proximal and distal to the balloon 220 may include one or more radiopaque markers, to facilitate visualization of the balloon outside a patient's body using radiographic imaging techniques and thus facilitate placement of the balloon 220 in a desired location. The balloon 220 may be inflated, according to various embodiments, by any suitable inflation fluid, such as but not limited to saline, contrast solution, water and air.
[0134] With reference now to FIG. 16 , the guide wire balloon system 200 is shown in kit form, with one embodiment of a packaging component. The guide wire device 202 and inflation device 222 are shown, along with a guide wire balloon packaging card 230 , a syringe 232 (for example 10 mL syringe with clips) for inflating the balloon 220 , and a guide wire balloon sheath valve introducer 234 . The sheath valve introducer 234 is generally a funnel-shaped device for facilitating introduction of the J-tip 216 into a vascular sheath through which the device 202 is to be introduced. In various embodiments, the system 200 or kit may include fewer or more components.
[0135] Referring now to FIGS. 17A-17D , further details of the guide wire device 202 are shown. FIG. 17A shows the entire length of the guide wire device 202 , though it may not be drawn to scale. FIG. 17B shows a close-up view of the J-tip portion 216 , including the core wire 208 , coil 214 and distal end 219 . For simplicity, the core wire 208 is shown as transitioning from a larger diameter proximally to a smaller, constant diameter distally. Alternatively, however, the core wire 208 may transition to a gradually smaller and smaller diameter distally.
[0136] FIGS. 17C and 17D show the inner workings of one embodiment of the valve portion 204 . As mentioned previously, in at least some embodiments, the proximal end 205 and valve/proximal portion 204 of the guide wire device 202 are hubless, meaning that no hub or other obstruction is located on these portions to interfere with the advancement of one or more additional devices over the proximal end 205 . The inflation device 222 is, of course, attached to inflate or deflate the balloon 220 , but once the balloon 220 is inflated, the inflation device 222 may be removed, leaving the balloon 220 inflated and the proximal end 205 (located outside the patient's body) free for advancement of one or more additional devices.
[0137] In the embodiment shown, the valve portion 204 includes a proximal portion of the shaft 206 , which forms an inflation lumen 213 , and the valve cap 203 , which is slidably disposed over the inflation hypotube 207 and abuts the proximal end of the shaft 206 . In this embodiment, the valve cap 203 has a different wall thickness than that of the shaft 206 . The valve cap 203 may be made of the same material as the shaft 206 or, in alternative embodiments, a different material, such as but not limited to Nitinol, stainless steel, other metals or polymers. The inflation hypotube 207 , which is fixedly attached to an inner surface of the proximal end of the shaft 206 , may also be made of Nitinol, stainless steel or any other suitable material, and may be the same material as the shaft 206 and the valve cap 203 in one embodiment. The inflation hypotube 207 also includes the inflation port 209 , as described previously. In one embodiment, a silicone ring 241 (or “coating”) may be positioned on an inner surface of the valve cap 203 at or near its distal end. The silicone ring 241 may form a seal between the valve cap 203 and the inflation hypotube 207 , thus preventing the escape of inflation fluid between the two.
[0138] The valve portion 204 may also include a proximal end cover 246 attached to the proximal end 205 of the valve cap 203 . A post 242 (or “wire”) may be attached to the proximal end cover 246 , and a flow regulator 240 may be attached to the post 242 . Finally, the valve portion 204 may also include a stop member 244 on an inside surface of the inflation hypotube 207 at or near its proximal end. The stop member 244 may stop the flow regulator 240 from being drawn too far proximally and thus being pulled out of the inflation hypotube 207 .
[0139] These components of the valve portion 204 effectively form a two-part valve, where inflation fluid is blocked from escaping externally by the valve cap 203 and is blocked internally by the flow regulator 240 . The valve portion 204 may work as follows. Referring to FIG. 17C , to close the valve, the valve cap 203 is advanced distally to cover the inflation port 209 and abut the proximal end of the shaft 206 . In this valve-closed configuration, the flow regulator 240 is positioned distal to the inflation port 209 , thus blocking inflation fluid from entering the inflation hypotube 207 from the inflation lumen 213 . Thus, again, inflation fluid is prevented from entering or exiting the inflation lumen 213 by the flow regulator 240 and the valve cap 203 .
[0140] Referring now to FIG. 17D , to open the valve, the valve cap 203 may be moved proximally to expose the inflation port 209 and to move the flow regulator 240 proximal to the inflation port 209 . At this point, with the valve portion 204 in the valve-open position, the inflation device 222 may be used to pass contrast solution, saline solution, air, water or other inflation medium through the inflation port 209 and into the inflation lumen 213 of the shaft 206 to inflate the balloon 220 . When the balloon 220 is inflated, the valve cap 203 may be once again advanced distally to the valve-closed position, thus covering the inflation port 209 and blocking the inflation hypotube 207 with the flow regulator 240 . If desired, the inflation device 222 may then be removed from the guide wire device 202 , and one or more therapeutic devices may be passed over the hubless proximal end 205 of the device 202 . In one embodiment, the inflation device 222 may be used to advance and retract the valve cap 203 , as will be described further below.
[0141] Referring to FIGS. 18-25 , balloon segments of various alternative embodiments of guide wire balloon devices are shown. In general, in all the embodiments described in FIGS. 18-25 , various structural configurations are included to provide a desired flexibility/stiffness profile immediately proximal to the balloon, between the two ends of the balloon, and immediately distal to the balloon. In the embodiment shown in FIG. 18 , for example, the balloon segment 212 includes a balloon 220 , an shaft 206 proximal to the balloon 220 , an extension 227 extending distally from the shaft 206 and on which the balloon 220 is mounted, a core wire 208 extending through the extension 227 and attached to the shaft 206 via an attachment member 242 , and a coil 214 wrapped around the core wire 208 and a portion of the extension 227 . The extension 227 fits within the distal end of the shaft 206 . The balloon 220 may be mounted to the extension 227 via one or more threads 224 and epoxy 246 or other form of adhesive. The extension 227 includes a spiral cut 211 , which increases its flexibility. The core wire 208 may have a varying diameter along its length, for example a widened section to close off the inner lumen of the extension 227 to prevent air or other inflation fluid from escaping distally out of the balloon 220 . The proximal end of the core wire 208 may be attached to the shaft 206 by any suitable attachment member 242 or attachment means. For example, attachment member 242 may be a weld, glue, other adhesive, anchor or the like.
[0142] With reference to FIG. 19 , in an alternative embodiment, a balloon segment 412 of a guide wire balloon device may include a balloon 420 , a shaft 406 , a core wire 408 with a thinner balloon section 408 ′ and a coil 414 around at least part of the core wire 408 . The shaft 406 may, for example, be a hypotube. A flattened proximal end of the core wire 408 may be attached to the shaft 406 by any suitable means, such as welding, gluing, soldering or the like. Coil 414 provides extra support to the balloon segment 412 .
[0143] In another alternative embodiment, and with reference now to FIG. 20 , a balloon segment 442 of a guide wire balloon device may include a balloon 440 , a shaft 446 , a core wire 448 with a thinner balloon section 448 ′ and a coil 444 around at least part of the core wire 448 . In this embodiment, the thinner balloon section 448 ′ may include a bend 450 (or fold), which may help provide stress relief when the balloon segment 442 is bent during use. A flattened proximal end of the core wire 448 may be attached to the shaft 446 by any suitable means, such as welding, gluing, soldering or the like. Coil 444 provides extra support to the balloon segment 442 .
[0144] Referring to FIG. 21 , in another alternative embodiment, a balloon segment 462 of a guide wire balloon device may include a balloon 460 , a shaft 466 , a core wire 468 with a thinner balloon section 468 ′ and a coil 464 around at least part of the core wire 468 . In this embodiment, a proximal end of the core wire 468 , which may be part of the thinner balloon section 468 ′, may include (or be attached to) a ball-shaped member 470 . Shaft 466 may include an inward facing stop member 472 . Together, the ball-shaped member 470 and the stop member 472 act as a joint, allowing the balloon segment to flex at the joint and thus accommodate bending during use. Coil 464 provides extra support to the balloon segment 462 .
[0145] Referring to FIG. 22 , in another alternative embodiment, a balloon segment 482 of a guide wire balloon device may include a balloon 480 , a shaft 486 , a core wire 488 with a thinner balloon section 488 ′ and a coil 484 around at least part of the core wire 488 . In this embodiment, a proximal end of the core wire 488 ″ may be flattened to facilitate attachment to shaft 486 via welding, gluing, soldering or the like. The thinner balloon section 488 ′ may continue up to the proximal end 488 ″. Coil 484 provides extra support to the balloon segment 482 .
[0146] Referring to FIG. 23 , in another alternative embodiment, a balloon segment 502 of a guide wire balloon device may include a balloon 500 , a shaft 506 , a core wire 508 with a thinner balloon section 508 ′ and a coil 504 around at least part of the core wire 508 . In this embodiment, as in the previously described embodiment, a proximal end of the core wire 508 ″ may be flattened to facilitate attachment to shaft 506 via welding, gluing, soldering or the like. The thinner balloon section 508 ′ may continue up to the proximal end 508 ″. Unlike the previous embodiment, in this embodiment, the thinner balloon section 508 ′ is not covered with the coil 504 . This will make the thinner balloon section 508 ′ more flexible than in the previously described embodiment.
[0147] With reference now to FIG. 24 , in yet another alternative embodiment, the balloon segment 522 may include a balloon 520 , a shaft 526 having a spiral cut 527 along at least a portion of its length proximal to a proximal end of the balloon 520 , a core wire 528 extending from the distal tip 536 and through the extension balloon segment 522 and attached to the shaft 526 proximally, and a coil 524 disposed over at least a portion of the core wire 528 distal to the balloon 520 . The core wire 528 may include a thinner balloon section 528 ′ underlying the balloon 520 and a flattened proximal end 528 ″, which may facilitate attachment to the shaft 526 via welding, gluing, soldering or the like. As in most or all embodiments, the shaft 526 forms an inflation lumen 530 for inflating the balloon 520 . Due to the spiral cut 527 , the shaft 526 will typically be coated or covered with a sheath, such as a polymeric coating or sheath, to prevent inflation fluid (air, saline, etc.) from leaking through spiral cut 527 . The balloon 520 may be mounted to the shaft 526 proximally and to the core wire 528 distally via threads 534 and epoxy 532 or other form of adhesive.
[0148] Referring now to FIG. 25 , in another alternative embodiment, the balloon segment 542 may include a balloon 540 , a shaft 546 proximal to the balloon 540 , an extension tube 556 extending distally from the shaft 206 and on which the balloon 540 is mounted, a core wire 548 extending through the extension 556 and attached to the shaft 546 via welding, gluing, soldering or the like of a flattened proximal end 548 ″ to the shaft 546 , and a coil 544 wrapped around a portion of the core wire 548 distal to the balloon 540 . The extension tube 556 attaches to the proximal end of the shaft 546 by fitting around its outer surface. In one embodiment, the extension tube 556 may be made of polyamide or other flexible plastic. The balloon 540 may be mounted to the extension tube 556 via one or more threads 554 and epoxy 552 or other form of adhesive. The core wire 548 may have a varying diameter along its length, such as a thinner balloon section 548 ′ and a wider proximal end 548 ″. The wider proximal end 548 ″ may be attached to the shaft 546 by any suitable attachment means.
[0149] The foregoing examples of balloon sections of various embodiments of a guide wire balloon device are provided for exemplary purposes only and should not be considered as an exhaustive list or as limiting the scope of the claims of this application. Various features and elements described above may be interchanged or eliminated and/or other features may be added in alternative embodiments.
[0150] Referring now to FIGS. 26A-26F , further detail of the inflation device 222 is shown. As shown in FIG. 26A , the inflation device 222 may include one or more markings 223 , for example to show which direction the parts of the device 222 may be moved to release or secure the guide wire device, to open or close the valve, etc. As shown in FIG. 26B , the inflation device 22 may suitably include a high pressure luer 250 a , 250 b , extension tubing 252 , O-ring seal 254 , a handle body main portion 256 , a handle body cap 258 , a flared hypotube 260 , a one-way stopcock/luer 262 , a handle outer shell slider 264 , a handle outer shell main portion 266 , an outer shell pin 268 , a handle luer cap 270 , and a non-vented luer cap 272 . In various alternative embodiments, one or more of these components may be changed, replaced with another like component, repositioned, etc., without departing from the scope of an inflation device as described in the claims. In various embodiments, the components of the inflation device 222 may be made of one or more polymers, metals or combinations thereof. Some or all of the various components will be described in further detail below, in relation to an exemplary method for using the device 222 .
[0151] FIGS. 26C-26F are top, perspective, side and end-on views of the inflation device 222 , respectively, according to one embodiment. The inflation device 22 may have any of a number of suitable configurations and dimensions. For example, it may be advantageous to have an inflation device 222 that can be easily held in one hand, so a user may use his/her other hand for holding a syringe or other inflation medium carrying/injecting device coupled with the inflation device 222 . The inflation device 222 may also have a size selected such that a user may grip the outer shell slider 264 with one hand and the outer shell main portion 266 with the other hand, to move the two portions 264 , 266 away from and towards one another to open and close the valve of the guide wire balloon device. In some embodiments, for example, an outer diameter of the outer shell slider 264 may be between about 20 mm and about 30 mm, or more preferably between about 24 mm and about 25 mm. In some embodiments, the inflation device 222 may have an overall length from one end of the luer cap 270 to an opposite end of the non-vented luer cap 272 of between about 120 mm and about 150 mm, or more preferably between about 130 mm and about 140 mm. These and other dimensions may be different in alternative embodiments and are thus provided here for exemplary purposes only.
[0152] Referring now to FIGS. 27A and 27B , a method for using the inflation device 222 , according to one embodiment, will be described. First, the proximal end of a guide wire balloon device (not shown in these figures) may be passed into the inflation device via the wire lumen 226 on the handle luer cap 270 (inflation port 226 visible in FIG. 15 ). In one embodiment, the proximal end of the guide wire device may be advanced into the inflation device 222 until it contacts a stop. To lock the inflation device 222 onto the guide wire device, the two slide members 250 a , 250 b that make up the high pressure luer 250 a , 250 b may be moved towards one another within the outer shell slider 264 and the outer shell main portion 266 , as designated by the words “SECURE” and the accompanying arrows marked on the outer shell slider 264 and the outer shell main portion 266 . Next, as in FIG. 27A , the outer shell slider 264 and outer shell main portion 266 may be moved apart from one another to open the valve of the guide wire balloon device (i.e., to expose the inflation port 209 shown in FIGS. 15 , 17 C and 17 D). This may optionally be designated, for example, by markings 223 , such as the “VALVE OPEN” marking and arrows shown in FIG. 26A . At this point (or, alternatively, at any time before this point), an inflation medium carrying and injection device, such as but not limited to a syringe, pump or the like, may be attached to the stopcock/luer 262 , and inflation medium may be introduced into the guide wire to inflate the balloon. In some embodiments, for example, approximately 2-3 mL of diluted contrast solution (e.g., about 50% contrast and about 50% saline) may be used to inflate the balloon. In other embodiments, more or less fluid and/or some other fluid may be used, such as saline, undiluted contrast, water, air or the like.
[0153] Next, as illustrated in FIG. 27B , once the balloon of the guide wire device (or other expandable member) is inflated, the outer shell slider 264 and outer shell main portion 266 may be moved toward one another to close the valve of the guide wire balloon device, thus locking the inflation medium inside the balloon so that it maintains its inflated configuration. The slide members 250 a , 250 b of the high pressure luer 250 a , 250 b may next be moved away from one another to unlock the inflation device 222 from the guide wire device, and the inflation device 222 may then be removed from the guide wire device. At this point, the guide wire device has its balloon (or other expandable member) locked in the expanded/inflated configuration and has a hubless proximal end, over which one or more additional devices (such as vessel treatment devices) may be passed.
[0154] Once a vascular repair procedure is complete, or whenever the user wants to deflate the balloon of the guide wire device, the user may reattach the inflation device 222 to the guide wire device and repeat the steps outlined above, except that the inflation fluid is withdrawn instead of injected. This process may be repeated as many times as desired, for example to reposition the balloon of a guide wire balloon device within an iliofemoral artery, aorta and/or femoral artery one or more times. Alternatively, the user can reopen the valve positioned at the proximal end of the guide wire, which allows the inflation fluid to release through the valve opening resulting in the deflation of the balloon.
[0155] Turning to FIGS. 28 , 29 A and 29 B, another exemplary embodiment of a fluid regulator (valve) system is shown that includes an internal piston 609 that may be directed to engage and disengage in a fluid-tight manner an internal sealing member 607 within the proximal end 303 of the guide wire shaft, for example, when piston 609 is moved axially relative to the guide wire shaft. For example, as shown in FIGS. 28 and 29A , the piston 609 may be advanced distally until the piston 609 engages the sealing member 607 in a distal position by passing through the sealing member 607 and effectively blocking the inner diameter of the sealing member, preventing flow out of the catheter and through the sealing member 607 . Thus, in the distal position, the lumen 320 of the guide wire shaft may be substantially sealed or closed, for example, after delivering sufficient fluid into the lumen 320 to inflate the balloon 302 , providing the valve in a closed position. Conversely, as shown in FIG. 29B , the piston 609 may be retracted proximally until the piston 609 reaches a position proximal to an outlet or side port 306 in a side wall of the proximal end 303 of the tubular member. The internal lumen 320 may communicate with the external environment adjacent the proximal end 303 through the outlet 306 when the piston 609 is retracted to the proximal position such that fluid may be delivered into or evacuated from the lumen 320 , for example, to inflate or deflate the balloon 302 (not shown), where the valve is in an open position.
[0156] In one aspect, the sealing member 607 can comprise an O-ring that is held stationary in the lumen of the guide wire. The O-ring can be constrained between a pair of small collars or sleeves inside of the lumen 320 , or in another aspect, the O-ring can be constrained by providing an indentation or crimp in the guide wire on one or both sides of the O-ring to hold it in place. In yet another aspect, the collar can comprise a pair of hypotubes 630 A and 630 B, or stainless steel tubes, as shown in FIG. 30 . The collars or hypotubes can restrain movement of the O-ring inside of the lumen of the guide wire. In another embodiment, the O-ring can be constrained in a groove machined in the internal lumen 320 . In yet another embodiment, the O-ring can be constrained by crimps or swaged features both proximally and distally of the O-ring formed in the body of the guide wire shaft 303 . As mentioned above, the sealing member 607 is opened and closed by sliding the piston 609 in and out of the inner diameter of the sealing member 607 , such as an O-ring. The O-ring can be kept static within the inner lumen 320 of the guide wire while the piston moves in and out of the inner diameter of the O-ring to close and open the valve, respectively. The inner diameter of the O-ring sealing member 607 should be less than the outer diameter of the guide wire shaft at that position in the guide wire, i.e., at the proximal end 303 . Thus, the inner diameter of the sealing member 607 should be smaller than the outer diameter of the guide wire, which in some embodiments can be about 0.035 inches. For example, the inner diameter of the sealing member 607 can have a range from about 0.004 inches to about 0.040 inches, or in another embodiment, can have a range from about 0.004 inches to about 0.035 inches, or in yet another instance, the inner diameter of the sealing member 607 can be about 0.010 inches. The O-ring used for the valve can comprise any material that is known in the art for use with a guide wire or catheter and, in particular, can comprise EPDM (ethylene propylene diene monomer) or, in another aspect, can comprise silicone, rubber, Viton, nitrile, polyurethane, PVC, or thermoplastic elastomers, such as styrene-ethylene/butylene-styrene (SEBS), styrene-butadiene-styrene (SBS), styrene-ethylene/propylene-styrene (SEPS), thermoplastic polyolefins (TPO), among others.
[0157] The O-ring sealing member can be loaded into the lumen 320 of the guide wire utilizing a loading process that can include an O-ring loading tool. The first hypotube, or the distally-positioned hypotube 630 B, can be placed on the tool, which looks like a wire that can fit inside of the guide wire lumen, followed next by the O-ring, and another hypotube, or the proximally-positioned hypotube 630 A. The hypotubes 630 A and 630 B and the O-ring 607 can then be inserted into the lumen 320 of the guide wire by advancing the loading tool into the lumen 320 . The loading tool can be advanced distally into the lumen 320 until it abuts a distal crimp in the lumen 320 . A distal crimp 608 formed in the guide wire can act as a positive stop against the distal hypotube 630 B.
[0158] The adjacent hypotubes 630 A and 630 B can have a slightly larger inner diameter than the O-ring 607 in order to hold the O-ring 607 in place, thus, essentially having an inner diameter sized to maintain the O-ring within the lumen 320 of the guide wire. In one aspect, the hypotubes 630 A and 630 B can have an inner diameter in the range of about 0.005 inches to about 0.035 inches and, in another aspect, can have a range from about 0.005 inches to about 0.034 inches, and in yet another aspect can have an inner diameter of approximately 0.017 inches. The outer diameter of the hypotubes 630 A and 630 B should be slightly less than the inner diameter of the guide wire shaft 320 at the position of the hypotubes 630 A and 630 B and can be in the range of about 0.006 inches to about 0.035 inches or, in another aspect, can have an outer diameter of about 0.025 inches. The hypotubes 630 A and 630 B can have a length between about 0.004 inches and about 1 inch and, in one aspect, a length of about 0.100 inches. It is preferred that both hypotubes have the same length, but is not necessary. The hypotubes can be any material that is appropriate for its use adjacent the O-ring and, in one aspect, can be a stainless steel tube. It is preferred that the hypotubes 630 A and 630 B are made out of a rigid or semi-rigid material in order to properly restrain movement of the O-ring and, in one aspect, can be any metal, ceramic or plastic material. In one embodiment, the hypotubes can be of polyimide, polyether ether ketone, polyether block amide, or other polymers that have a high durometer and rigid stiffness.
[0159] The hypotubes 630 A and 630 B can be kept in place by any method known in the art, such as by swaging, providing an adhesive to adhere the hypotubes in place, laser welding, providing a crimp, or any other appropriate process. In one aspect, the hypotubes 630 A and 630 B can be held in place by providing indentations or crimps in the guide wire. A middle crimp, or a second indentation 606 , and a distal crimp 608 , or a first indentation, can be provided on either end of the hypotubes 630 A and 630 B, as shown in FIG. 30 . The second crimp 606 can be placed proximal to the proximally-positioned hypotube 630 A and helps to hold the hypotubes in place, while the distal crimp 608 can be placed distal to the distally-positioned hypotube 630 B and can also hold the hypotubes in place but it can also be used to aid in positioning the O-ring 607 between the two hypotubes. A crimp can be used to either restrict the inner diameter of the proximal end of the shaft 320 or to hold something in place, like the hypotubes, or both. The crimping of the wire can reduce the diameter of the wire. In one aspect, the inner diameter of the lumen 320 containing the crimp can range from about 0.006 inches to about 0.035 inches and, in another aspect can range from about 0.006 inches to about 0.034 inches, and in still another aspect can range from about 0.0225 inches to about 0.0275 inches. In yet another aspect, each end of the hypotube can have a different diameter crimp. In one preferred embodiment, the middle crimp 606 proximal to hypotube 630 A can have a diameter of about 0.0215 inches while the distal crimp 608 , distal to hypotube 630 B, can have a diameter of about 0.0165 inches. However, the middle and distal crimps 606 and 608 can have different values than those indicated or can have values that are identical to one another. In adding the crimp marks to the wire, they can either be added manually using a crimp tool or by an automated process, using standard procedures known in the art. The crimp marks can comprise two crimp marks or indentations in the wire, with a middle section therebetween which is not indented. In the case of the distal crimp 608 , it is preferred to have the center section C of the distal crimp 608 at a set distance from the proximal end 603 of the wire, as shown in FIG. 30 . This ensures that the placement of the O-ring sealing member 607 will be positioned properly. In one aspect, the center C of the distal crimp 608 can be positioned at about 0.95 inches to about 0.97 inches from the proximal end 603 of the wire, as shown by distance Y in FIG. 30 . Thus, if the distal crimp 608 is placed too far distal along the wire, then the O-ring 607 may not be positioned properly within the lumen of the guidewire.
[0160] The proximal end 303 of the guide wire can be provided with a valve handle assembly, or piston assembly 600 , which can be used to slide the piston 609 back and forth axially in and out of the lumen of the guide wire and in and out of the inner diameter of the sealing member 607 . The piston assembly 600 , can include a handle 610 with an integrated piston portion or piston 609 of smaller diameter. The distal end of the piston 609 can be provided with a rounded tip or edge for easier insertion through the inner diameter of the O-ring when closing the valve. When the piston assembly 600 is moved in the proximal position, as shown in FIG. 29B , the one or more side ports 306 in the body of the guide wire are exposed such that they are no longer covered up or blocked by the piston 609 ; this is the valve open position. When the piston assembly 600 is in its closed position, as shown in FIG. 29A , the sealing member 607 is engaged by the piston to prevent fluid from escaping from the lumen 320 to the one or more side ports 306 and the valve is closed by the inner piston 609 . In one aspect, there is at least one side port 306 and, in another aspect, there can be any number of side ports as are necessary for fluid flow. In yet another aspect, there can be up to 8 side ports positioned in the proximal end of the guide wire. The one or more side ports 306 can be provided in the body of the guide wire at a proximal end and if there are more than one, the ports can be equidistantly spaced from one another or they can be placed in any position that is most appropriate for fluid flow through and into the inner lumen 320 of the guide wire and into the open valve. In one aspect, the side ports can be laser cut holes into the guide wire such that the laser cut holes provide low restriction to fluid flow therethrough for inflation and deflation of the balloon, and it can be further electropolished such that the holes are burn-free allowing the O-ring to be loaded into the lumen of the guide wire without getting cut or damaged. The diameter of these side port holes can be any diameter that is appropriate for proper fluid flow therethrough and can range from about 0.0005 inches to about 0.03 inches, and in another aspect, can be from about 0.0005 inches to about 0.0265 inches, and in still another aspect, can be about 0.007 inches in diameter.
[0161] In order for the piston assembly 600 to be movable within the lumen 320 of the guide wire, it can be provided with a frictional element, such as a spring element 640 , that collapses when placed into the lumen 320 of the guide wire and acts to push against the inner diameter of the guide wire to provide a certain level of friction. The amount of friction can be adjusted by the bend angle on the frictional element, by the thickness of the spring members, and/or by the modulus of the material chosen for the frictional element. The spring element 640 can be made by splitting the wire of the piston, such as creating a “w” shaped wire, or from a separate piece of material, such as a split tube, for example, that is welded onto the wire of the piston 609 , such that it acts as a spring to create friction between the spring element and the guide wire lumen to prevent the valve from being inadvertently opened or closed. A “w” shaped wire can be formed in the wire of the piston, such that the straight piston is bent at a section of the wire to make several bends resembling the peaks and valleys of the letter w. Fewer or additional bends may be added to decrease or increase the amount of friction. Alternatively, other materials or elements can be used as a friction element such as elastomeric materials, another O-ring, or multiple O-rings, for example.
[0162] In one embodiment, the frictional element 640 can be formed by adding a separate element, or split tube, welded onto the piston 609 , which can then be bent after it is attached to the piston 609 to provide the frictional element 640 . Alternatively, a separate tube can first be bent into shape and then attached to the piston. The frictional element may also be bonded or crimped onto the piston. Where a split tube 614 is welded onto the piston 609 of the piston assembly 600 prior to shaping it in the bent configuration, it can be welded at a location on the piston assembly 600 that is on the piston near the distal end 611 of the piston 609 , as seen in FIG. 31A . In one aspect, the split tube 614 can be welded by laser beam welding. The split tube 614 can be welded at a distal end 615 of the split tube 614 positioned a certain distance from the distal end 611 of the piston 609 such that the split end 616 of the tube is positioned a certain distance from the handle 610 . The split end 616 , in one embodiment, can be formed by splitting a tube in half such that two leaves or wings 612 are created. In another aspect, the split tube 614 can be attached at a position that is about 0.250 inches proximal to the distal end 611 of the piston 609 . In yet another aspect, the split tube 614 can be welded at a position that is between about 0.010 inches to about 6 inches from the distal end 611 . The diameter of the split tube 614 can be slightly larger than that of the piston and, in one aspect, the diameter of the split tube can be about 0.017 inches. The split tube 614 outer diameter, not including the formed frictional portion, can be slightly smaller than the inner diameter or lumen of the guide wire to allow it to slide freely in and out of the lumen without interference. The wings 612 of the frictional element, once formed or shaped, are larger than the inner diameter of the guide wire so that it can cause friction upon axially shifting the piston in the lumen.
[0163] In one embodiment, the diameter of the piston 609 can be about 0.015 inches and the diameter of the handle 610 can be about 0.0320 inches. In another embodiment, the diameter of the piston can range between about 0.005 inches to about 0.035 inches, or in another aspect from 0.005 inches to about 0.034 inches. The diameter of the handle 610 can range between about 0.005 inches to about 0.04 inches, and in another aspect can range from about 0.005 inches to about 0.038 inches. The piston 609 can be provided integrated with the handle 610 such that there is a reduction in diameter from the handle to the piston and, in one aspect, this reduction can be about 50%. The piston can also be electropolished to aid in minimizing wear upon the O-ring each time the piston is inserted into the inner diameter of the O-ring. The distal end of the piston, i.e., the end being inserted into the inner diameter of the O-ring, can be provided as a fully rounded end. The piston can also be electropolished, ground smooth, lapped or chemically polished to provide a smooth surface, e.g., a burn-free surface, to slide smoothly without cutting the O-ring each time it is opened and closed. The length of the piston assembly 600 , can have a length that is long enough to be inserted into the lumen 320 of the guide wire and advance distally through the lumen 320 and through the inner diameter of the O-ring an appropriate distance to provide a closed state of the valve. In one aspect, the length of the piston assembly 600 can be about 1.355 inches, where the handle 610 can be about 0.50 inches in length and the piston 609 can be about 0.855 inches in length. In a preferred embodiment, the length of the piston 609 can be greater than the length of the handle 610 , where these two lengths can range from about 0.010 inches to about 6 inches. Alternatively, the handle 610 can be longer than the piston 609 . In another preferred embodiment, the diameter of the piston can be less than the diameter of the handle. Alternatively, the handle can have a smaller diameter than the piston. In one aspect, the piston 609 can comprise at least 50% of the length of the piston assembly and, in a preferred aspect, at least 60% of the piston assembly, and still more preferred, at least 63% of the piston assembly. In one embodiment, the handle 610 can comprise 37% of the piston assembly 600 while the piston 609 can comprise about 63% of the piston assembly. The handle and piston can be formed as one unit and can be formed out of stainless steel, however, other materials of construction appropriate for use with the guide wire can be provided. It is preferred that the diameter of the handle provides a similar profile as the guide wire shaft or lumen, e.g., has a similar diameter, or still more preferred that the diameter of the handle is slightly smaller than the diameter of the lumen so as not to catch on catheters or other devices sliding over it, in order to prevent the valve from being inadvertently opened or closed. It is preferred that the diameter of the piston is compatible with the O-ring inner diameter, and is still more preferred that the diameter of the piston is slightly larger than the inner diameter of the O-ring, for example, by at least 0.0005 inches, in order to form a seal, yet not too large where it could tear the O-ring. In one aspect, the O-ring inner diameter is 0.010 inches and the piston outer diameter is about 0.015 inches.
[0164] The length of the split tube 614 can be shorter than the overall length of the piston 609 extending distal from the handle 610 . In one aspect, the length of the split tube can be about 0.35 inches, with the leaves or wings 612 having a length of about 0.25 inches. In another aspect, the length of the split tube can vary between about 0.030 inches to about 6 inches and the length of the wings can vary between about 0.020 inches to about 6 inches, or in another aspect the length of the wings can vary between about 0.020 inches to about 5.950 inches. Any length of the wings is appropriate that can be made into the frictional element. In one aspect, the length of the wings can comprise at least about 10% of the overall length of the split tube, in another aspect, at least about 60% of the overall length of the split tube, and in yet another aspect, can comprise at least about 70% of the overall length of the split tube, and in still another aspect, at least about 71% of the overall length of the split tube.
[0165] One method of forming the frictional element includes attaching the split tube, which can comprise two leaves or wings, and placing the split tube and piston on a bending tool between two pins. The leaves or wings of the split tube can then be spread such that the wings can catch on the two pins and can be spread apart and away from the piston to stick outward in a V-shape. The piston is then shifted in a manner that further separates the wings of the split tube and brings them in contact with a second set of pins. The second set of pins can bring the outward ends of the wings together while at the same time bending the mid-section of the wings around the first set of pins to result in a diamond-shape orientation of the wings. This diamond-shape orientation can result in the frictional element of the piston, as shown in FIG. 31B . Alternatively, other methods for forming bends in a wire or tube may be employed.
[0166] Another method of forming a frictional element is to machine, stamp, etch or laser cut a flat or curved piece of metal, and form it into a spring. This formed sheet metal component can then be attached to the piston and pushed onto the inner diameter of the guide wire shaft to provide friction. In one embodiment, a frictional element can be formed from a flat sheet of sheet metal. The sheet metal can have a hole cut in the middle of it and bend along bend lines, where the hole remains as a centerpoint. When bent, the sheet metal can look like a backwards ‘C.’ This bent sheet metal can then be attached to the piston, by inserting the piston through the hole of the bent sheet metal. In other embodiments, a plurality of sheet metal parts can be bent and formed without cutting a hole in the middle and can be attached to the piston.
[0167] One benefit of utilizing the frictional element-split tube design is that the bends in the split tube are located symmetrical to one another such that upon inserting the piston into the lumen 320 of the guide wire the frictional element provides for a centering of the piston in the lumen 320 . If a w-wire is used, it may sometimes provide an off-center positioning of the piston due to its w-orientation of the bends, i.e., non-symmetrical bends on either side of the wire.
[0168] The spring element 640 in a relaxed, uncollapsed state can be seen in FIG. 31B , prior to it being introduced into the lumen 320 . When the piston and piston assembly 600 are placed inside of the lumen 320 of the guide wire, the spring element 640 can collapse inside of the lumen 320 , as seen in FIG. 30 .
[0169] At the proximal end 602 of the guide wire, can be provided another crimp or third indentation 604 . This crimp, or proximal crimp 604 , can provide a positive stop on opening the sealing member 307 , i.e., proximally withdrawing the piston 609 from the lumen 320 , which interacts with the frictional element 640 such that it catches on the proximal end of the frictional element 640 and prevents the frictional element 640 and handle from being pulled out of the lumen 320 upon withdrawing the piston 609 in a proximal direction. This proximal crimp 604 can provide a narrowed or smaller diameter than that of the guide wire and, in one aspect, can provide a reduced diameter of about 0.006 inches to about 0.035 inches, or in another aspect from about 0.006 inches to about 0.034 inches. In yet another aspect, the reduced diameter can be about 0.0275 inches or less. In still another aspect, the proximal crimp 604 can have a diameter of about 0.0225 inches. The piston 609 becomes visible upon opening valve because the diameter of the piston 609 is less than the diameter of the piston assembly 600 such that a difference in thickness between the two becomes visible. Upon closing the valve, i.e., moving the piston 609 in a distal direction further into the lumen 320 and into the inner diameter of the O-ring, the handle 610 and, in particular, the larger diameter of the handle in comparison to the piston, can provide a positive stop against the guide wire shaft upon closing the valve due to a stepped portion on the handle (not shown in Figures). When the diameter of the handle is similar to the diameter of the guide wire shaft, this can allow for a smooth transition between the two in the closed position to allow devices to pass over the proximal end of the guide wire. As previously mentioned, the difference in the diameter of the handle and the piston (e.g., for instance, where the handle diameter is greater than the piston diameter) can provide a visual feedback that the valve is in an open state. When the piston shaft is no longer visible, then the valve is in a closed state. In another aspect, the piston can be marked, plated, covered in colored heat shrink, or painted a different color to improve contrast to show that it is in an open state.
[0170] Turning to FIGS. 32A and 32B , another embodiment of a fluid regulator (valve) system is shown that includes the sealing member (e.g., O-ring) 607 attached to the piston 609 , and reciprocating distally past the fill port(s) 306 to seal it in the closed position, i.e., covering/blocking the fill ports 306 with the piston 609 to prevent any fluid from escaping or entering, and shifted proximally of the fill port(s) 306 to allow fluid flow. In this embodiment, the O-ring can move with the piston and can also act as a friction element.
[0171] Some benefits of having the piston assembly at the proximal-most end of the guide wire is that the there is a visual indication whether the valve is in a closed or open position based upon the position of the piston assembly. For instance, when the valve is in an opened position, the piston assembly is pulled proximally away from the guide wire such that it exposes the piston and exposes one or more side ports 306 . When the piston assembly is in this extended position, as shown in FIG. 29B or 32 B, a certain distance of the piston 609 is exposed. In one aspect, at least about 4 millimeters of the piston tube 609 are visible. When in the closed position, the piston is not visible outside of the lumen such that the user understands that the valve is closed. Another benefit of a valve system with a frictional element, is that the friction element of the piston assembly requires a certain force be exerted upon the proximal end to slide the handle proximal to the valve and thus, accidental opening or closing of the valve is prevented. The piston assembly allows for the user to easily open and close the valve manually and to do so multiple times, as necessary.
[0172] In addition, the sealing member 607 can have a small profile such that the outer diameter of the sealing member is smaller than the guide wire outer diameter. The small diameter and the way in which the O-ring is constrained on either end by a small hypotube sleeve allows for the profile of the O-ring as the sealing element to remain small. The integrated piston and design of the friction element allows for a small profile where the piston has an end integrated into a handle that substantially matches the outer diameter of the guide wire. Moreover, the piston 607 provided in the guide wire can be robust enough such that it allows other devices, such as introducers, to be passed over the valve. As the piston is integrated with the handle as a single unit, i.e., as the piston assembly, it can all be ground from stainless steel or other high strength metal or alloy to improve its robustness. The proximal end of the handle can be provided with a smooth rounded tip and the distal end of the handle can further provide a smooth transition to the main body of the guide wire when in the closed position, hence minimizing any sharp edges when passing other devices over the proximal end of the handle and guide wire assembly. Furthermore, the integrated frictional element can help to center the piston into the O-ring and to center the handle to the guide wire body to help maintain them coaxial to one another.
[0173] Other benefits are that when the valve is in the open position, there are minimal flow restrictions to any fluid that is introduced to allow for adequate inflation and deflation of the balloon. Multiple ports in the guide wire can help to reduce flow restrictions into the lumen of the guide wire. Additionally, there is provided a visual feedback to the user to determine if the valve is in an opened state or a closed state. This can be provided by a stepped transition from the piston to the handle, which can be visible when the valve is in the open position, providing the necessary visual feedback when the valve is in the open position. Another benefit is in having the frictional element along the piston can prevent accidental opening and/or closing of the valve provided by a spring force to increase friction to keep the valve from accidentally opening or closing.
[0174] Further benefits include the ability to open and close the valve manually by a user, even a user that is wearing gloves or a covering on the hands. Special tools are not required to open and close the valve. The amount of friction provided by the frictional element can be adjusted to allow for ease of opening and closing, yet to prevent an accidental opening or closing. Additionally, providing a stationary O-ring valve allows for multiple actuation of the valve with minimal wear upon the valve. Providing the valve in an open position where the piston is not engaged with the O-ring can minimize the effects of compression on the O-ring during storage. Alternatively, a non-stationary O-ring valve can also be provided upon the end of a piston, which can also provide for multiple actuation of the valve with minimal wear upon the valve.
[0175] The method of inflating the balloon provided herein also applies to the alternative valve embodiment provided above and in FIGS. 28-31B . In order to inflate the balloon, the sealing member 607 can first be opened by sliding or withdrawing the piston assembly 600 in a proximal direction to expose the piston 609 as well as exposing the holes 306 and opening the sealing member 607 , as shown in FIG. 29B . The balloon can then be inflated as already provided herein and in order to maintain the inflation of the balloon, the valve should be closed, as shown in FIG. 29A . To close the valve, the piston assembly 600 can be advanced in a distal direction until the piston 609 is no longer visible. This ensures that the distal end of the piston 609 has passed through the inner diameter of the sealing member, e.g., O-ring, closing off the valve, as well as blocking off the holes 306 and preventing any fluid from exiting therethrough. The piston assembly 600 can remain in this position until it is necessary to deflate the balloon, then the piston assembly can be withdrawn once more in the proximal direction to expose the piston at the proximal end of the guide wire and to slide the piston proximally out of the O-ring inner diameter to open the valve allowing the fluid to escape through the holes and O-ring and thus deflating the balloon. The side ports or holes 306 do not need to be completely exposed in order to allow for fluid to escape therethrough. There can be enough of a gap provide between the piston and, in particular, between the piston and the frictional element that even if the piston is not withdrawn completely to expose the holes, the gap between the piston and the holes is adequate to provide for fluid to escape therethrough. Similarly, the balloon can be inflated in a like manner in the embodiments of FIGS. 32A and 32B , only the method of closing and opening the valve varies.
[0176] Elements or components shown with any embodiment herein are exemplary for the specific embodiment and may be used on or in combination with other embodiments disclosed herein.
[0177] While the invention is susceptible to various modifications, and alternative forms, specific examples thereof have been shown in the drawings and are herein described in detail. It should be understood, however, that the invention is not to be limited to the particular forms or methods disclosed, but to the contrary, the invention is to cover all modifications, equivalents and alternatives thereof. | A method of reducing the risk of clinical sequelae to catheter induced vascular injuries may include introducing a guide wire into a vascular sheath residing in a blood vessel, proximally retracting the vascular sheath while leaving the wire in place, and observing indicia of the presence or absence of a vascular injury caused to the blood vessel by the vascular sheath or a procedural catheter previously advanced through the vascular sheath. If indicia of a vascular injury are observed, the method may further involve proximally retracting the guide wire to position the inflatable balloon adjacent the injury and inflating the balloon to reduce blood flow past the injury, while leaving the guide wire in place to provide subsequent access to the injury. The inflatable balloon can be inflated and deflated through a valve positioned at the proximal end of the guide wire. | 0 |
CROSS REFERENCE TO RELATED APPLICATIONS
This application is a continuation of U.S. patent application Ser. No. 09/531,626, filed Mar. 21, 2000, now U.S. Pat. No. 6,291,571.
BACKGROUND OF THE INVENTION
This invention relates to a lap edge sealant composition for sealing the lap joints of roofing materials, and more particularly, to a lap edge sealant having a high solids content and a low volatile organic compound (VOC) content.
In the field of single-ply commercial rubber roofing, sheets of roofing material are typically laid on a roof in an overlapping fashion and spliced together to form a continuous sheet which covers the roof Lap joints are typically used to splice adjacent sheets of roofing material together. The exposed seams of the lap joints are then sealed with an adhesive, typically, a caulking compound, to act as an additional seal to prevent penetration of moisture along the external seam. Currently, solvent-based adhesive sealants are used for sealing the lap joints of adjacent sheets of membrane roofing materials. Such sealants typically utilize aromatic solvents such as benzene, toluene, xylene, etc. However, such solvent-based sealants are environmentally undesirable as they typically contain over 350 grams per liter (3 pounds per gallon) of volatile organic compounds. Because of environmental concerns, many states are beginning to mandate products having no more than 250 grams per liter (2 pounds per gallon) of volatile organic compound (VOC) content.
Another disadvantage of solvent-based sealants currently in use is their low solids content, i.e., about 20 to 30%. As such sealants typically cure by solvent evaporation, high shrinkage (typically about 40-60%) can occur when using these sealants. As a consequence, the cured films may exhibit fissure-type cracking and degradation after long term outdoor exposure.
A number of adhesives have been developed which exhibit lower VOC levels. For example, Congelio et al., U.S. Pat. No. 5,817,708, teach a low VOC content (less than 250 g/l) solvent-based adhesive for use in joining thermoplastic materials. Patel et al., U.S. Pat. No. 5,495,040, also teaches a low VOC (less than 250 g/l) solvent-based adhesive for joining ABS molded articles. However, such adhesives are not specifically formulated for use as lap edge roofing sealants, nor do they have a high solids content.
Backenstow et al., U.S. Pat. No. 4,849,268 teach a 100% solids sealant for providing an internal seal to spliced roofing membranes which is formed from EPDM, butyl or silicone based caulking compositions. The sealant is applied in combination with a splicing cement to the internal portion of the splice. However, Backenstow et al. require that the sealant, splicing cement, and roofing membrane be compatible in order to avoid separation of the sealant from the cement. In addition, Backenstow et al. do not seal the exterior seam on the lap joint.
Accordingly, there is still a need in the art for a lap edge sealant which effectively seals the external lap joints of adjacent sheets of membrane roofing material, which has a high solids content, a low VOC content, and which exhibits low shrinkage upon curing.
SUMMARY OF THE INVENTION
The present invention meets those needs by providing a lap edge sealant composition having a high solids content, a low VOC content of less than 250 g/l, and which exhibits no more than about 35% shrinkage upon curing. By shrinkage, it is meant the decrease in volume of the sealant after curing. The sealant composition provides excellent adhesion to a variety of roofing materials such as EPDM.
In accordance with one aspect of the present invention, a lap edge sealant composition for sealing the lap joints of roofing materials is provided comprising a rubbery polymer, a thermoplastic rubber, a tackifier, and a solvent, where the composition has a solids content of from about 65 to 90% and a VOC content of less than about 250 g/l.
Preferably, the rubbery polymer comprises EPDM. The thermoplastic rubber preferably comprises a styrene-ethylene/propylene copolymer.
The tackifier is preferably selected from the group consisting of aliphatic hydrocarbon resins, polybutene, and combinations thereof.
The solvent is preferably selected from the group consisting of aliphatic hydrocarbons, para-chlorobenzotrifluoride, and blends thereof. The aliphatic hydrocarbons are preferably selected from the group consisting of n-pentane, n-hexane, n-heptane, n-octane, and naphtha. The naphtha may comprise high flash naphtha solvent or VM&P (Varnish Makers and Painters) naphtha. In one preferred embodiment of the invention, the solvent comprises from about 26% by weight para-chlorobenzotrifluoride and from about 74% by weight VM&P naphtha. In another preferred embodiment, the solvent comprises from about 33% high flash naphtha and 67% VM&P naphtha.
The sealant composition also preferably includes an accelerator/cure package, which preferably comprises a mixture of a sulfur-containing composition and zinc oxide.
In a preferred form, the sealant composition comprises: a) from about 3 to 6% by weight of a rubbery polymer; b) from about 1 to 5% by weight of a thermoplastic rubber; c) from about 1 to 10% by weight of a tackifier; d) from about 30 to 50% by weight of a filler; and e) and from about 5 to 35% by weight of a solvent.
The sealant composition of the present invention may be applied at a job site under a variety of weather conditions to the lap joints of overlapping sheets roofing materials such as EPDM. The sealant composition exhibits low shrinkage upon curing, i.e., less than about 35%.
Accordingly, it is a feature of the present invention to provide a lap edge sealant having a high solids content, a low VOC content, and which exhibits low shrinkage upon curing. Other features and advantages of the invention will be apparent from the following detailed description, the accompanying drawing, and the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of the sealant composition of the present invention being applied to seal a lap joint of roofing membranes.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The lap edge sealant of the present invention provides an improvement over currently available lap edge adhesives or sealants in that the VOC content of the composition is less than 250 grams per liter (about 1.7 pounds per gallon) with no more than about 35% shrinkage upon curing, and preferably, less than about 20% shrinkage. The finished cured films are typically 30% thicker than prior art cured films and do not exhibit fissure-type cracking or degradation after long term outdoor field exposure. For example, the typical film thickness in its center portion after application is about 0.20 inches. With typical lap edge sealants, the film thickness will be reduced to as thin as 0.08 inches or less after curing. With the high solids lap edge sealant of the present invention, the film thickness is reduced to only about 0.14 to about 0.16 inches thick.
The lap edge sealant composition of the present invention preferably comprises, as the rubbery polymer component, an ethylene-propylene-diene terpolymer (EPDM). A preferred EPDM rubber for use in the present invention is a low Mooney viscosity EPDM terpolymer commercially available from Uniroyal Chemical under the designation Trilene 77. Mooney viscosity is a measure of the viscosity of a rubber as determined by a Mooney shearing disk viscometer. The viscosity is indicated by the torque required to rotate a disk embedded in a rubber specimen and enclosed in a die cavity under specified conditions. For the EPDM rubbers disclosed herein, a large rotor is used, and the test temperature is 125° C. with a running time of 4 minutes. For typical commercially available EPDM rubbers, the Mooney viscosity is from about 1 to 80. The EPDM rubbers used in the present invention have a low Mooney viscosity of from about 1 to 40, which ensures that the final compounded sealant will have a high solids content with low shrinkage and a low press-flow viscosity for ease of gunnability from a tube, pail or drum.
Other suitable low Mooney viscosity EPDM terpolymers include Trilene 56, 65, 66, and 67 and Royalene LV-1125, LV-1142 and LV-1145, available from Uniroyal Chemical, and Keltan 2506 and 7040, available from DSM Copolymer. Other low Mooney viscosity EPDM terpolymers are Nordel 1320, commercially available from Dupont Dow Elastomer, and TXA-6070, commercially available from DSM Copolymer.
A thermoplastic rubber is also included in the composition to gel the sealant (provide sag resistance) and add cohesive strength. Preferably, the thermoplastic rubber comprises a copolymer of styrene-ethylene/propylene, which is commercially available from a variety of sources. A preferred copolymer for use in the present invention is available from Shell Chemical Company under the designation Kraton G-1701 (which contains 37% styrene). Other suitable thermoplastic rubbers include Kraton G-1702 (28% styrene) and Kraton G-1726 (30% styrene).
The tackifier in the sealant composition preferably comprises an aliphatic hydrocarbon resin, polybutene, or combinations thereof. The tackifier is preferably included to provide the adhesive composition with high initial adhesivity and softness. Preferred aliphatic hydrocarbon resin tackifiers for use in the present invention include Escorez 5300 and 5340, a fully hydrogenated polycyclic hydrocarbon resin available from ExxonMobil Chemical. A preferred polybutene tackifier is Indopol H-300, commercially available from Amoco Chemical. Other suitable polybutene tackifiers include Indopol H-100, H-1500 and H-1900 (available from Amoco Chemical) and Parapol 450, 700, 950, 1300, 2400 and 2500 available from ExxonMobil Chemical.
Suitable fully hydrogenated polycyclic hydrocarbon resins include Escorez 5380 and 5320, available from ExxonMobil Chemical and Regalrez 1018, 1085, 1094, 1126, 1128, 1139, 3102, 5095 and 6108, available from Hercules. Additional aliphatic hydrocarbon resins include Escorez 1102, 1304 and 1315 available from ExxonMobil Chemical; Eastotac H-100, H-115, H-130 and H-142, available from Eastman Chemical; Wingtack 10 and 95 available from Goodyear Chemical; Adtac LV, Piccopale 100, Piccotac B, 95 and 115, Piccovar AB-180, Regalrez 1018, available from Hercules; and Nevtac 10, 80, 100 and 115, available from Neville Chemical.
The adhesive composition also preferably contains a compatible plasticizer for the rubbery polymer component which imparts softness to the composition. Suitable plasticizing agents include liquid polyisobutylene, for example, Vistanex CP-24, or LM-MH, both of which are commercially available from Exxon Chemical. Other suitable liquid polyisobutylenes include Vistanex LM-S, LM-MS and LM-H, available from ExxonMobil Chemical and Oppanol B-10, B12 and B-15, available from BASF Corporation.
The composition may also include a an oil such as mineral oil which functions as a low viscosity plasticizer to provide flexibility to the composition at low temperatures. A preferred mineral oil is available from Pennzoil Company under the designation Drakeol 10B.
Preferred solvents for use in the present invention include para-chlorobenzotriflouride or aliphatic hydrocarbons such as n-pentane, n-hexane, n-heptane, n-octane and naphtha. High flash naphtha solvent or VM&P (Varnish Makers and Painters) naphtha are the preferred aliphatic hydrocarbons for use in the invention. The aliphatic hydrocarbon solvents are commercially available from a variety of suppliers including Ashland Chemical, ExxonMobil Chemical, Eastman Chemical and Shell Chemical. Para-benzotrifluoride is commercially available from Occidental Chemical Company, Dallas Tex. under the designation Oxsol 100. The solvent preferably comprises either a blend of high flash naphtha solvent (90 solvent) and VM&P naphtha or a blend of para-chlorobenzotrilfluoride and VM&P naphtha.
The sealant composition may optionally include a deodorant mask such as Cherry mask #5236, commercially available from Andrea Aromatics, Princeton, N.J., which masks the odor of the solvent. Other suitable masking agents are Cherry Almond 183-301 and Citrus 173-218, available from Alpine Aromatics International, Inc. (Piscataway, N.J.), #18293 and #18294 available from Atlanta Fragrance (Kennesaw, Ga.), Masking Fragrance AP-970, available from Kraus & Company, Inc. (Oak Park, Mich.) and Fruity 91754, Fruity Vanilla 83576 and Non-Descript 95624 available from Stanley S. Schoenmann, Inc. (Clark, N.J.).
The lap edge sealant composition also includes an accelerator/cure package or system for the rubber polymer component. The present composition may be cured using several well-known curing systems including sulfur and sulfur-containing systems as well as zinc oxide. Typically, about 0.2 to about 2.0% by weight of the accelerator/cure package in the composition is sufficient. Preferably, the accelerator/cure package comprises a mixture of sulfur, tetramethylthiuram disulfide (TMTD), 2-mercaptobenzothiazyl disulfide (MBTS), butyl zimate, stearic acid, and zinc oxide.
Suitable accelerators for use in the present invention include, but are not limited to, thioureas such as ethylene thiourea, N,N-dibutylthiourea, N,N-diethylthiourea and the like; thiuram monosulfides and disulfides such as tetramethylthiuram monosulfide (TMTMS), tetramethylthiuram disulfide (TMTD), tetraethylthiuram monosulfide (TETMS), dipentamethylenethiruam hexasulfide (DPTH) and the like; benzothiazole sulfenamides such as N-oxydiethylene-2-benzothiazole sulfenamide, N-cyclohexyl-2-benzothiazole sulfenamide, N,N-diisopropyl-2-benzothiazolesulfenamide, N-tert-butyl-2-benzothiazole sulfenamide (TBBS) and the like; 2-mercaptoimidazoline, N-N-diphenylguanidine, N-N-di(2-methyl-phenyl)-guanidine, 2-mercaptobenzothiazole (MBT), 2-mercaptobenzothiazyl disulfide (MBTS), 2-(morpholinodithio)benzothiazole disulfide, zinc 2-mercaptobenzothiazole and the like; dithiocarbamates such as tellirium diethyldithiocarbamate, copper dimethyldiothiocarbarnate, bismuth dimethyldithiocarbamate, cadmium diethyldithiocarbamate, lead dimethyldithiocarbamate, zinc dibutyldithiocarbamate (butyl zimate), zinc diethyldithiocarbamate and zinc dimethyldithiocarbamate. Typically, the composition includes from about 0.5 to about 2.0% by weight of accelerator.
The cure package may also include a small amount of stearic acid (about 1 to 2 phr) to initiate the vulcanization process. The cure package may further include a surface treated activator (BIK-OT), available from Uniroyal Chemical and a substituted diphenylamine antioxidant (Naugard 445) available from Uniroyal Chemical.
The composition may further include conventional fillers such as carbon black, ground coal, and aluminum silicate. Other suitable fillers include treated fillers such as calcium stearate-treated calcium carbonate, which is available from George Marble Company of Tate, Ga. under the designation CS-11. Oleic acid may also be included as a wetting agent for the fillers. Desiccants such as calcium oxide (lime) may also be included in the composition.
The composition may also include a rheology modifier such as an organoclay and a wax such as a polyethylene wax.
The lap edge sealant composition also preferably includes an antioxidant to stabilize the thermoplastic rubber and the copolymer. While there are many suitable antioxidants, it is preferable to use a phenolic material which is commercially available from The Goodyear Tire & Rubber company under the product name Wingstay L.
The composition is preferably made by mixing all of the components in a medium to high powered mixer, such as a sigma blade or Banbury type mixer. The composition should be vigorously mixed to ensure good dispersion of all the components.
Referring now to FIG. 1, the lap edge sealant composition may be used to seal the lap joints of adjacent sheets of synthetic rubber roofing materials by applying the composition to at least one overlapping edge of the sheets. To achieve a uniform application, the lap edge sealant is preferably applied with a caulking gun nozzle as described in commonly assigned U.S. Pat. No. 5,000,361, the disclosure of which is incorporated herein by reference. As shown in FIG. 1, the sealant 10 is squeezed from the caulking gun 12 and applied to the overlap seam 20 of roofing material 18 .
The sealant composition may be applied in a variety of weather conditions and becomes fully cured at room temperature (i.e., about 24° C.) after about 21 days. The sealant preferably exhibits a sag of less than about 1½ inches when measured according to ASTM D2202.
In order that the invention may be more readily understood, reference is made to the following example which is intended to illustrate the invention, but not limit the scope thereof.
EXAMPLE 1
Three sets of lap edge sealants were prepared in accordance with the present invention. The proportions of each component in the sealants designated as 1 A, 1 B, 1 C, 2 A, 2 B, 2 C, and 3 A, 3 B, and 3 C are listed in Tables 1-3 below as parts by weight.
TABLE 1
Compound
1A
1B
1C
EPDM 1
60
60
60
styrene-ethylene/propylene
48
48
48
copolymer 2
EPDM 3
20
20
20
polyisobutylene 4
80
80
80
polyethylene wax
30
30
30
carbon black
20
20
20
antioxidant
2.4
2.4
2.4
organoclay
40
40
40
treated calcium carbonate
660
660
660
metallic oxide silica
20
20
20
lime
20
20
20
tackifier(s)
88
88
88
mineral oil
30
30
30
para-chlorobenzotrifluoride 5
112
112
112
naphtha
315
310
315
n-butyl acetate
—
6
—
Cherry mask #5236
—
—
0.6
1 Nordel 1320 from Dupont Dow Elastomer
2 Kraton G-1701 from Shell Chemical Company
3 TXA-6070 from DSM Copolymer
4 LMMH from Exxon Chemical
5 Oxsol 100 from Occidental Chemical Company
TABLE 2
Compound
2A
2B
2C
EPDM 1
70
70
70
styrene-ethylene/propylene
50
50
50
copolymer 2
polyisobutylene 3
80
80
80
polyethylene wax
30
30
30
antioxidant
2
2
2
carbon black
20
20
20
treated calcium carbonate
750
500
500
metallic oxide silica
20
20
20
aluminum silicate
—
250
—
tackifier(s)
95
95
95
lime
20
20
20
oleic acid
2
2
2
ground coal
—
—
250
organoclay
40
40
40
mineral oil
40
40
40
naphtha
100
100
100
VM&P naphtha
200
200
200
1 Trilene 77 from Uniroyal
2 Kraton G-1701 from Shell Chemical Company
3 Vistanex CP-24 from Exxon Chemical
TABLE 3
Compound
3A
3B
3C
EPDM 1
70
70
70
styrene-ethylene/propylene
50
50
50
copolymer 2
polyisobutylene 3
80
80
80
polyethylene wax
30
30
30
antioxidant
2
2
2
carbon black
20
20
20
calcium carbonate
750
750
750
filler
20
20
20
tackifier(s)
85
85
85
lime
20
20
20
oleic acid
2
2
2
organoclay
30
30
30
mineral oil
30
30
30
Accelerator/cure package
14
12.7
6.6
naphtha
71
71
71
VM&P naphtha
141
141
141
1 Trilene 77 from Uniroyal
2 Kraton G-1701 from Shell Chemical Company
3 Vistanex CP-24 from Exxon Chemical
All of the above sealants were tested to determine VOC content, solids content, press-flow viscosity, weight per gallon, specific gravity, sag at 25° C. and 70° C., flexibility at −30° C., adhesion to EPDM, and shrinkage. The results are shown below in Table 4. VOC content was determined by ASTM Standard test method D 3960. Solids content was determined by ASTM standard test method C 681. Press-flow viscosity was determined by ASTM standard test method D 2452 (time to extrude 20 grams at 40 psi at 25° C.). The weight per gallon and specific gravity were determined by ASTM standard test method D 1475. Sag at 25° C. and 70° C. were determined by ASTM standard test method D 2202. Flexibility at −30° C. was determined by ASTM standard test method C 711. Adhesion to EPDM was determined by ASTM standard test method C 794. Shrinkage was determined by ASTM standard test method C 733 for volume shrinkage of sealants.
TABLE 4
VOC
Solids
Press-flow
Weight
Sag @
Sag @
Content
Content
viscosity
per gallon
specific
25° C.
70° C.
Flexibility
Adhesion
Product
(g/l)
(%)
(seconds)
(lbs)
gravity
(inches)
(inches)
@ −30° C.
to EPDM
Shrinkage
1A
244
69.1
18
9.83
1.18
2.14
1.73
Good
Good
31.4%
1B
249
68.2
16
9.75
1.17
3.48
3.11
Good
Good
32.3%
1C
247
71.3
39
9.91
1.19
0.60
2.06
Good
Good
29.2%
2A
194
86.4
61
11.93
1.43
0.44
0.55
Good
Excellent
14.2%
2B
211
84.8
36
11.57
1.39
2.56
2.00
Good
Excellent
15.8%
2C
219
83.2
36
10.9
1.31
0.08
0.10
Good
Excellent
17.3%
3A
213
83.6
34
11.84
1.42
1.02
1.03
Good
Good
17.1%
3B
215
84.1
35
11.94
1.43
1.16
0.87
Good
Good
16.6%
3C
213
83.6
25
11.84
1.42
1.28
1.46
Good
Good
17.1%
The sealants were also tested for center and edge cracking using ASTM standard test method C 1257. None of the sealants exhibited center or edge cracking.
While certain representative embodiments and details have been shown for purposes of illustrating the invention, it will be apparent to those skilled in the art that various changes in the methods and apparatus disclosed herein may be made without departing from the scope of the invention, which is defined in the appended claims. | A lap edge sealant composition is provided for adhering together overlapping sheets of roofing material which includes a rubbery polymer such as EPDM, a thermoplastic rubber, a tackifier, and a solvent, where the solvent is selected from aliphatic hydrocarbons, para-chlorobenzotrifluoride, or blends thereof. The lap edge sealant has a high solids content of about 65 to 90%, a volatile organic compound (VOC) content of less than about 250 g/l, and exhibits no more than about 35% shrinkage upon curing. | 2 |
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
The United States Government has rights in this invention pursuant to Contract No. W-31-109-Eng-38 between the U.S. Department of Energy and the University of Chicago representing Argonne National Laboratory.
BACKGROUND OF THE INVENTION
Field of the Invention
This invention relates to the operation of electrostatic precipitators for use in fossil fuel fired power plants which use low sulfur fuels to generate heat or electricity. More particularly, this invention relates to an improved apparatus and process for increasing the particulate removal efficiency of electrostatic precipitators used in such facilities by the conversion of sulfur dioxide, present in the flue gas stream, to sulfur trioxide which reacts with the fly ash to improve the electrical conductivity of the fly ash.
Fuels, typically fossil fuels, are combusted with air in a boiler to generate heat. The heat generated is converted into useful energy to heat a product or process, or to produce electricity. The fossil fuels normally used, such as coal or oil, contained sulfur. When coal is burned, the products of combustion include particulate matter (commonly known as fly ash), sulfur dioxide (SO 2 ) and water, which are exhausted from the boiler as part of an exhaust stream known as flue gas. Fly ash and SO 2 are both undesirable pollutants and must be removed from the flue gas to a desirable level. These levels are normally set by environmental regulatory agencies.
In most fossil fuel-fired plants, fly ash in the flue gas stream is removed by electrostatic precipitation. An electrostatic charge is applied to the fly ash in the flue gas stream as the flue gas passes between charged electrodes contained in an electrostatic precipitator. The particulate matter is deposited upon the electrode having the opposite charge to that of the fly ash and is later removed. The efficiency with which fly ash is removed from the flue gas stream by the electrostatic precipitator depends in part upon the electrical conductivity of the fly ash. This, in turn, is influenced by the absorption by the particles of fly ash, of sulfuric acid (H 2 SO 4 ) that is generated as a by-product of the combustion process through the reaction of SO 2 with oxygen and water in the flue gas stream. The sulfuric acid deposited upon the particulate matter imparts a degree of electrical conductivity to the particulate and promotes the electrostatic precipitation process.
When fuels having a relative large sulfur contents are used, only a portion of the SO 2 generated by combustion is converted to the sulfuric acid required for conditioning the fly ash. Absent expensive process equipment for removing SO 2 from the flue gas stream, the excess SO 2 in the flue gas is exhausted to the atmosphere. This is undesirable since SO 2 can cause pollution problems, such as acid rain. One alternative to reduce the amount of SO 2 generated by the combustion process is to use fuel that is lower in sulfur content. However, the combustion of low sulfur coal would also result in the amount of SO 3 produced by the combustion process being insufficient to produce the quantities of sulfuric acid required to efficiently remove fly ash at the electrostatic precipitator. To combat this problem power plant operators have been introducing sulfur trioxide (SO 3 ) from other sources into the flue gas stream or generating SO 3 by catalytic means within the exhaust system of the power plant.
Archer et al., U.S. Pat. No. 3,993,429 and Hankins et al., U.S. Pat. No. 5,244,642, disclose burning sulfur in air to produce SO 2 , which is then catalytically oxidized to SO 3 . The SO 3 generated by the processes of Archer and Hankins is directed into the flue gas stream where it reacts with water vapor from the combustion process to form sulfuric acid, which is in turn absorbed by the fly ash. The process of Hankins further provides for a control loop that maintains a constant level of SO 2 produces based upon the fly ash content of the exhaust gas.
Processes that burn sulfur such as Archer and Hankins et al., provide a simple, direct solution to the problem of providing a sufficient amount of SO 3 in a flue gas stream to permit the efficient removal of fly ash by electrostatic precipitation. However, these processes require the addition of extra sulfur to the flue gas exhaust stream which must be removed later in the combustion process by additional pollution control equipment. Further, a separate combustion system must be monitored and maintained. The catalytic system for conversion of SO 2 to SO 3 must also be maintained and replenished with fresh catalysts.
Spokoyny et al., U.S. Pat. No. 5,320,052 describes a sulfur trioxide conditioning system that includes a catalytic converter that oxidizes a portion of the sulfur dioxide in a flow of flue gas to sulfur trioxide. The catalytic converter incorporates a catalyst support, which is disposed across at least a portion of the cross section of a main duct from a burner to a heat recovery apparatus, and a catalyst on the catalyst support. The amount of the catalyst surface exposed to the flow of flue gas is selectively varied to control the conversion of sulfur dioxide to sulfur trioxide. Spokoyny et al., U.S. Pat. No. 5,540,755 discloses an aspirating device to draw SO 2 laden flue gas through the catalyst beds.
The devices of the Spokoyny patents provide a catalytic oxidation system for conversion of SO 2 to SO 3 . As with any catalytic system, provisions must be made to compensate for the pressure drop across the catalytic bed. This pressure drop represents a loss of energy that must be made up for with additional fans or blowers. Further, as with all catalytic systems the catalyst becomes deactivated or poisoned with use. The catalyst must be monitored and replenished as needed. This is extremely difficult from a plant operating perspective when the catalyst is located within a transport line as disclosed in the Spokoyny patents.
Alternative catalytic oxidation systems have been disclosed by Altman et al., U.S. Pat. No. 5,011,516, and U.S. Pat. Nos. 5,356,597 and 5,547,495 to Wright et al.
Altman describes an alternate approach in which a flue gas stream is divided into two streams. One flue gas stream is passed through a heat exchanger and continues on to a bag house for particulate removal. The second flue gas stream is passed over a catalyst. A portion of the sulfur dioxide in the second stream is oxidized to sulfur trioxide, and the two streams are then merged back into the main flue gas flow prior to the bag house. The second stream is not passed over a heat exchanger since the gas stream must be maintained at a high temperature to permit efficient conversion of sulfur dioxide to sulfur trioxide. While of interest, this approach has major drawbacks when implemented. System thermal efficiency is reduced because less heat is recovered. Further, there is typically insufficient mixing of the slip stream and the main flow at the point where they rejoin due to an insufficient pressure differential. Moreover, the Altman patent does not disclose any approach which permits control of the amount of sulfur trioxide produced, responsive to variations in the sulfur content of the fuel and changes in other operating parameters.
The Wright patents disclose a catalytic oxidation system in which a catalyst bed is maintained in a slidably mounted platform within the duct connecting the combustion chamber with the electrostatic precipitator. While the devices of Wright provide for the easy removal of the catalyst bed from the flue gas duct for servicing, the problems associated with catalyst deactivation and poisoning is still present.
A system for the simultaneous destruction of SO 2 and NO x by a plasma reactor has been disclosed by Mathur et al., U.S. Pat. No. 5,020,457. Ammonia, methane, steam, hydrogen, nitrogen or combinations of these gases are subjected to plasma conditions sufficient to create free radicals, ions or excited atoms. These ions or atoms are then reacted with SO 2 and NO x in the flue gas stream to produce environmentally safe compounds or compounds that can easily be removed from the flue gas stream. In PLASMA-ASSISTED CLEANUP OF FLUE GAS, by S. K. Dhali it is suggested to convert SO 2 and NO x to stable acid mists which can be removed by mist eliminators.
BRIEF SUMMARY OF THE INVENTION
An object of this invention is to provide an apparatus for the conversion of at least part of the sulfur dioxide present in the flue gas into sulfur trioxide without the need to provide significant modification to the existing gas treatment apparatus and process.
Another object of this invention is to provide an apparatus for the conversion of at least part of the sulfur dioxide present in the flue gas into sulfur trioxide wherein such apparatus is not readily deactivated or damaged by the exhausted flue gas.
Another object of this invention is to provide a process for the conversion of at least a part of the sulfur dioxide present in the flue gas into sulfur trioxide without the need to provide significant modification to the existing gas treatment apparatus and process.
Another object of this invention is to provide a process for the conversion of a portion of the sulfur dioxide present in the flue gas stream that will minimize the energy lost due to lost heat and process inefficiencies.
These and other objectives of the invention, which will become apparent from the following description, have been achieved by a novel system for the oxidation of the sulfur dioxide, present in a primary flue gas stream, to sulfur trioxide. The sulfur dioxide is discharged from a fossil-fuel fired combustion device through a main duct to particulate removal equipment for subsequent discharge to the atmosphere. The conversion system comprises a low temperature plasma reactor, the interior of which defines a plasma volume. A portion of the primary flue gas stream is directed to the plasma volume and is passed through the plasma volume. A fraction of the sulfur dioxide present in the flue gas is converted into a sulfur trioxide to form a sulfur trioxide-laden flue gas. The sulfur trioxide laden flue gas is then returned to the primary flue gas stream upstream of the particulate removal equipment. Preferably the plasma reactor is a low temperature nonequilibrium plasma reactor. Low-temperature herein means an increase in the temperature of the gas exiting from the plasma volume of from about 25° C. to about 100° C. above the temperature of the gas entering the plasma volume.
The means for directing a portion of the primary flue gas stream to the plasma volume may withdraw flue gas from the ductwork located upstream or downstream of the particulate removal equipment. Preferably the gas is removed from the ductwork downstream of the particulate removal equipment in order to reduce the dust loading within the plasma volume.
An air preheater assembly may be arranged upstream of the particulate removal equipment electrostatic precipitator in the main duct. The means for returning the sulfur trioxide laden flue gas to the primary flue gas may be attached to the main duct upstream or downstream of the air preheater assembly.
Preferably the plasma reactor comprises a plasma reactor tube having an inlet end and a discharge end, wherein the interior of the plasma reaction tube from the inlet to the discharge defines the plasma volume; a microwave generator coupled to the plasma reactor tube; and an electric power supply electrically coupled to the microwave generator.
The means for directing a portion of the primary flue gas stream to the plasma volume, the plasma reactor and the means for returning the sulfur trioxide laden flue gas to the primary flue gas stream may be located within the main duct upstream of the particulate removal equipment.
Preferably, the conversion system for the oxidation of sulfur dioxide in a primary flue gas stream, that is discharged from a fossil-fuel fired combustion device, comprises; a fuel burning device for the combustion of sulfur containing fuels, an electrostatic precipitator; and a plasma reactor. The electrostatic precipitator has an inlet end and an outlet end. A first duct connects the fuel burning device to the inlet end of the electrostatic precipitator. The first duct transports the primary flue gas comprising particulate matter, sulfur dioxide and oxygen to the electrostatic precipitator. A second duct is attached to the outlet of the electrostatic precipitator for the discharge of the cleaned flue gas to the atmosphere. A diverter duct is attached to the second duct, wherein the diverter duct transports a portion of the flue gas contained in the second duct to the plasma reactor. The plasma reactor converts a portion of the sulfur dioxide present in the flue gas passing through the plasma reactor to sulfur trioxide to produce a sulfur trioxide-laden flue gas. A return duct attached to the plasma reactor returns the sulfur trioxide-laden flue gas to the first duct upstream of the electrostatic precipitator.
The plasma reactor is preferably a low temperature plasma reactor that comprises, a plasma reactor tube, a microwave generator coupled to the plasma reactor tube, and an electric power supply electrically coupled to the microwave generator. The plasma reactor tube has an inlet end and a discharge end. The interior of the plasma reaction tube from the inlet to the discharge defines the plasma volume. Other low temperature plasma reactor systems, i.e., barrier discharge, radio frequency, etc., can be used.
The conversion process for the oxidation of sulfur dioxide in a primary flue gas stream to sulfur dioxide comprises, the following steps: a) removing a portion of the primary gas stream; b) directing this stream to a low temperature plasma reactor, the interior of which defines a plasma volume; c) passing the portion of the primary flue gas through the plasma volume, such that a fraction of the sulfur dioxide therein is converted into sulfur trioxide to form a sulfur trioxide-laden flue gas; and d) returning the sulfur trioxide laden flue gas to the primary flue gas stream upstream of particulate removal equipment.
The conversion process may also include removing heat from the primary gas stream and transferring the heat to the fossil-fuel fired combustion device inlet air. The removal of heat from the primary gas stream typically takes place upstream of the particulate removal equipment in the main duct.
Preferably, the process of this invention for the efficient removal of particulate matter from a flue gas of a fossil fuel-fired burner that burns low sulfur fossil fuel (less than 1 weight percent), prior to the discharge of the flue gas to the atmosphere comprising the following steps: a) providing a flue gas comprising particulate matter, sulfur dioxide, water in the gaseous form, and oxygen; b) conducting the flue gas to the upstream side of the electrostatic precipitator; c) conducting the flue gas through the electrostatic precipitator; d) diverting a portion of the flue gas downstream of the electrostatic precipitator; e) conducting the diverted flue gas to a plasma reactor and passing the flue gas through the plasma reactor wherein a portion of the sulfur dioxide present in the flue gas is converted to sulfur trioxide to form a sulfur trioxide laden flue gas; f) returning the converted flue gas to the upstream side of the electrostatic precipitator; g) and conducting exhaust gas from the downstream end of the electrostatic precipitator.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF DRAWINGS
With this description of the invention, a detailed description follows with reference being made to the accompanying figures of drawings which form part of the specification, in which like parts are designated by the same reference numbers, and of which:
FIG. 1 is a schematic diagram of a boiler waste gas treatment process illustrating a number of possible locations from which flue gas can be drawn for direction through the plasma reactor in order to accomplish the process of this invention;
FIG. 2 is a schematic diagram of the waste gas treatment process illustrating the apparatus of this invention illustrating the preferred embodiment of this invention;
FIG. 3 is a schematic illustration of one possible design of a low temperature plasma reactor;
FIG. 3a is a schematic illustration showing a further modification of the low-temperature reactor of FIG. 3;
FIG. 4 is a fragmented diagram of a side view illustrating one possible placement for the low temperature plasma reactor, for use with the apparatus of this invention, within the piping between an air preheater and an electrostatic precipitator;
FIG. 5 is an enlarged cross-sectional view of area 5 of FIG. 4 illustrating the placement of the low temperature reactor within the piping between an air preheater and an electrostatic precipitator;
FIG. 5a illustrates the embodiment of FIG. 5 without a plasma conduit; and
FIG. 6 is a schematic diagram illustrating one possible placement of the low temperature plasma reactor for use with the apparatus of this invention, wherein the plasma reactor is placed outside of the piping between the air preheater and the electrostatic precipitator.
DETAILED DESCRIPTION OF THE INVENTION
Description of the Preferred Embodiment(s)
A typical flue gas clean up system modified to form the apparatus and process of this invention is shown generally at 10 of FIG. 1. This system is typically used to treat the products of combustion produced from coal containing less that 1 weight percent sulfur. The flue gas contains less than 1000 parts per million (ppm) of SO 2 , and preferably less than 400 ppm of SO 2 . This process diagram has been simplified to focus on the process components that are relevant to the practice of this invention. Flue gas is generated by a coal-fired boiler or furnace (not shown in FIG. 1). The flue gas, which contains SO 2 , water vapor or gas, and fly ash, along with other products of combustion, proceeds through duct 12 to economizer 14 wherein some heat is removed from the flue gas to preheat the incoming boiler water. The flue gas exits the economizer 14 and passes through duct 16 to the air preheater 18 where heat is removed from the flue gas in order to preheat air for combustion prior to its introduction to the boiler. The flue gas exiting the air preheater 18 passes through duct 20 and enters the electrostatic precipitator 22 (hereinafter "ESP") where fly ash is removed from the flue gas by processes known in the industry. The gas exiting the ESP 22 passes through exhaust duct 24 and enters an exhaust stack 26 where it is discharged to the atmosphere. The flue gas may pass through other process components to further treat or condition the flue gas. These components have been deleted from the drawing in order to simplify it and the following discussion. Other process components known in the field may be used with the process of the invention, as needed, without taking away from the basic concept of this invention.
Flue gas may be directed to a plasma reactor 28 from one of any number of places along the flue gas clean up system 10. For example, a portion of flue gas may be withdrawn from duct 12, prior to entry into economizer 14, and diverted through economizer bypass duct 30 to the inlet 32 of plasma reactor 28. Alternatively, flue gas can be diverted from duct 16 through air preheater diverter duct 34, from duct 20 through ESP diverter duct 36, or from duct 24 through stack diverter duct 38 (a preferred embodiment) to the inlet 32 of plasma reactor 28.
The preferred embodiment of the instant invention is illustrated in FIG. 2. As in FIG. 1, the diagram of the flue gas clean up process has been simplified to reduce the complexity of the drawing and the associated discussion. In the preferred embodiment flue gas from a coal fired boiler 40 exits through duct 16, enters air preheater 18, passes on to the ESP 22 through duct 20 and exits through exhaust duct 24 into stack 26. In the preferred embodiment, a portion of the flue gas passing through exhaust duct 24 is diverted through stack diverter duct 38 to the inlet 32 of plasma reactor 28. The flue gas stream proceeds through the plasma reactor 28, exits through plasma outlet 42, and passes through plasma reactor return duct 44 as the flue gas is returned to duct 16 for reentry into the flue gas system upstream of the air preheater. A fan 45 may be installed in the return duct 44 to move flue gas from the low pressure conditions in exhaust duct 24 to the high pressure conditions in duct 16. It is believed that flue gas passing through exhaust duct 24 will be substantially free from fly ash and have a higher concentration of SO 2 and oxygen. Flue gas removed from this point in flue gas clean up system will result in less wear on the plasma reactor 28 due to a much lower level of fly ash, while having improved conversion of SO 2 to SO 3 due to the higher level of SO 2 and O 2 . Further, any energies in the form of heat that is added to the flue gas by the plasma reactor 28 can be recovered by the preheater 18.
Any low-temperature nonequilibrium plasma reactor can be used with this invention. One example of a suitable plasma reactor is shown in U.S. Pat. No. 5,542,967. A low-temperature plasma reactor herein is defined as a plasma reactor that increases the temperature of the gas exiting the plasma reactor 28 over the temperature of the incoming gas by from about 25° C. to about 100° C. and preferably from 25° C. to about 50° C. A preferred low-temperature nonequilibrium reactor for use with this invention is shown generally at 50 in FIG. 3. An electrical power source 52 provides electricity to a microwave generator power supply 54. The power supply 54 is cooled by a cooling water source 56. The power supply 54 provides a stable source of power to microwave generator 58 thereby producing a steady source of microwave radiation 60 in the range of from about 10 -3 m to about 5×10 -1 m (1 millimeter to 50 cm). The input power levels and intensity will be determined by the mass flow rates of the flue gas to be conditioned and the degrees of SO 2 to SO 3 conversion that is required. The microwave radiation 60 passes through a plasma volume 62 within which the microwave radiation is of sufficient energy and intensity to partially ionize the chemical constituents of the gas stream passing therethrough. The plasma volume 62 may be defined by a conduit 64 in the form of a duct or tube that directs the flow of flue gas through a delineated volume. The conduit 64 should be constructed of a material that is transparent to microwave radiation. Transparent herein means to permit the transmission of radiation without a significant loss in the amplitude of the radiation (Less than a 20% loss). Suitable materials, from which the conduit 64 may be constructed, include but are not limited to: ceramic, glass, or quartz. Alternatively, a window 65 that is transparent to the microwave radiation 60 may be installed in the wall of conduit 64, as shown in FIG. 3a. The microwave radiation 60 passes through the plasma volume 62 and on into the duct containing the flue gas. When a microwave source is used to generate the nonequilibrium plasma a suitable outer container or shield should be installed to absorb or contain the microwave radiation. Further, a waveguide 66 may be installed to direct the microwave radiation 60 to the plasma volume 62. The waveguide 66 helps in preventing a reduction in the intensity of the microwave radiation and to reduce side reactions or problems associated with the uncontrolled distribution of the microwave radiation 60. The microwave generator 58 is thereby coupled to the plasma volume 62 and the conduit 64 in that the microwave radiation 60 is transferred without being diminished significantly in amplitude.
The waveguide 66 referred to hereinabove is a conduit having a circular or rectangular cross-section for directing the microwave radiation 60 from the microwave generator 58 to the plasma reactor 28. The waveguide 66 can be constructed from any suitable material that is opaque and which reflects the microwave radiation 60. Suitable materials for the construction of the waveguide 66 include, but are not limited to: mild steel, stainless steel, aluminum, or iron. The waveguide 66 may be of any suitable linear geometry to direct the microwave radiation 60 as describe hereinabove.
Under normal operating conditions with the apparatus and process of this invention, as shown in FIG. 2, flue gas containing SO 2 and O 2 is removed from the exhaust duct 24 and is conducted via the stack diverter duct 38 to the plasma reactor 28. Typically, between 5 to 20 volume percent of the gas is diverted and most preferably 10 volume percent is diverted. The flue gas, which contains a mixture of SO 2 , O 2 , H 2 O gas, and products of combustion; such as carbon dioxide (CO 2 ), carbon monoxide (CO), nitrogen oxides (NO x ), and nitrogen, passes through plasma reactor 28 and in particular the plasma volume 62 defined hereinabove. The chemical compounds present in the flue gas stream are ionized to form distinct chemical species. The particular chemical compounds and the associated reactions involve SO 2 , O 2 , and H 2 O gas. Other reactions may occur, however, they are not important with respect to the instant invention. The important ionizations that take place with the plasma reactor for the purposes of this invention are as follows:
H 2 O+e→OH+H+e
H 2 O+O 2 +e→2OH+O+e
SO 2 +OH→HSO 3
After these chemical constituents leave the plasma volume 62 the following reactions are believed to occur:
SO 2 +O→SO 3 -
SO 3 +H 2 O→H 2 SO 4
HSO 3 +OH→H 2 SO 4
Between 50 and 99 volume percent of the SO 2 present in the gas stream is converted to SO 3 , and preferably between 80 and 90 volume percent of the SO 2 present in the gas stream is converted to SO 3 .
The sulfuric acid (H 2 SO 4 ) along with other gaseous components exits through plasma outlet 42, and passes through plasma reactor return duct 44 as the flue gas is returned to duct 16 for reentry into the flue gas clean up system. The H 2 SO 4 and the other gases mix with the gases present in the air preheater duct 16 and proceed through the system. As the H 2 SO 4 passes along with the flue gas, a portion of it combines with the fly ash thereby increasing its electrical conductivity. As the higher conductivity fly ash passes through the ESP 22 it is removed from the gas stream by operation of the unit. The other gases, including unreacted SO 2 proceed through the ESP 22 and out of the stack 26.
An alternative arrangement for the placement of the plasma reactor 28 is shown in FIGS. 4 and 5. FIG. 4 illustrates the installation of the plasma reactor 28 in duct 20 between the air preheater 18 and the ESP 22. Although this drawing demonstrates the installation of the plasma reactor 28 immediately upstream of the ESP 22, the plasma reactor 28 can be installed in any duct within the flue gas clean up system upstream of the ESP 22 (FIG. 5). In this embodiment the plasma conduit 64 is held in place within duct 20 by plasma reactor supports 68. A waveguide 66 conducts microwave radiation 60 from the microwave generator 58 through the wall 70 of duct 20 to the plasma reactor conduit 64. A window 72 that is transparent to the microwave radiation may be installed in wall 70 of duct 20 to provide for improved performance while maintaining the flue gas clean up system under preferred operating conditions. The window 72 can be constructed out of any suitable material such as silica glass, ceramic, or quartz. Flue gas, containing a mixture of SO 2 , O 2 , H 2 O gas and other gases, passes through the plasma conduit 64 and enters the plasma volume 62 wherein the SO 2 is dissociated and upon exiting the plasma volume 62 is converted to SO 3 . The plasma volume 62 can also be created in situ within the flue gas stream without the use of the plasma reactor conduit 64 as is shown in FIG. 5a.
Another embodiment of the instant invention is illustrated in FIG. 6 where the plasma reactor 28 is placed external to a duct 74 within the flue gas clean up system. Flue gas is diverted from the duct 74 through plasma inlet duct 76 and into the plasma reactor 28. The flue gas returns to duct 74 through plasma return duct 78 containing fan 80.
Thus, in accordance with the invention, there has been provided an apparatus for the conversion of at least part of the flue sulfur dioxide present in the flue gas into sulfur trioxide without the need to provide significant modification to the existing gas treatment apparatus and process. There has also been provided an apparatus for the conversion of at least part of the sulfur dioxide present in the flue gas into sulfur trioxide wherein such apparatus is not readily deactivated or damaged by the exhausted flue gas. There has also been provided a process for the conversion of at least a part of the sulfur dioxide present in the flue gas into sulfur trioxide without the need to provide significant modification to the existing gas treatment apparatus and process. Additionally, there has been provided a process for the conversion of a portion of the sulfur dioxide present in the flue gas stream that will minimize the energy lost due to lost heat and process inefficiencies.
With this description of the invention in detail, those skilled in the art will appreciate that modification may be made to the invention without departing from the spirit thereof. Therefore, it is not intended that the scope of the invention be limited to the specific embodiments that have been illustrated and described. Rather, it is intended that the scope to the invention be determined by the scope of the appended claims. | An apparatus and process that utilize a low temperature nonequilibrium plasma reactor, for improving the particulate removal efficiency of an electrostatic precipitator (ESP) are disclosed. A portion of the flue gas, that contains a low level of SO 2 O 2 H 2 O, and particulate matter, is passed through a low temperature plasma reactor, which defines a plasma volume, thereby oxidizing a portion of the SO 2 present in the flue gas into SO 3 . An SO 2 rich flue gas is thereby generated. The SO 3 rich flue gas is then returned to the primary flow of the flue gas in the exhaust treatment system prior to the ESP. This allows the SO 3 to react with water to form H 2 SO 4 that is in turn is absorbed by fly ash in the gas stream in order to improve the removal efficiency of the EPS. | 2 |
REFERENCE TO RELATED APPLICATIONS
[0001] This is a Continuation of U.S. patent application Ser. No. 10/487,920, which is the U.S. National Phase of International Patent Application No. PCT/EP2002/09641, having an international filing date of Aug. 28, 2002, and claims priority to United Kingdom application GB01210277, filed Aug. 30, 2001. The entire disclosure of U.S. patent application Ser. No. 10/487,920 is incorporated herein by reference.
FIELD OF THE DISCLOSURE
[0002] The present disclosure relates to tools such as embossing tools or tape printers.
BACKGROUND
[0003] Known embossing tools are generally hand held and mechanically operated. Embossing tools are designed to emboss selected characters or numbers on an elongated strip of embossable material. This embossable material can be of any suitable construction and may for example be of a thermoplastic resin. The tape is mechanically deformed by squeezing the tape between a die set of a selected character, number or the like. The die set is carried by first and second wheels. The tape passes between the first and second wheels. To emboss an image on the tape, a portion of one of the wheel is urged against the opposite wheel to deform the tape therebetween. The wheels are rotated so that the selected character or like is at the embossing position.
[0004] Tape printing apparatus of the type with which the present disclosure is generally concerned are disclosed for example in EP-A-322918 and EP-A-322919 (Brother Kogyo Kabushiki Kaisha) and EP-A-0267890 (Variatronics). The printers each include a printing device having a cassette receiving bay for receiving a cassette or tape holding case. The ink ribbon may be included in the same cassette as the image receiving tape or in a different cassette.
[0005] In these known tape printing apparatus, an image is input via a keyboard. The image is printed onto the image receiving tape using a thermal printhead. In these known tape printers, the heat from the thermal printhead causes ink from the ink ribbon to be transferred to the image receiving tape. It is also known for an image to be transferred directly to thermally sensitive image receiving tape, without the need for an ink ribbon.
[0006] Both of these products can be designed to be relatively small. As the embossers and tape printers are relatively small, it can be difficult to see the numbers or characters of the respective input means. In the case of the tape printer, the input means usually comprises a keyboard or a dial. In the case of an embosser, the input means comprises a rotatable wheel which can be moved. Additionally, visually impaired people can have problems in ascertaining whether or not the right letter or symbol has been printed. A further problem exists hen the embosser or tape printer is used by someone who is learning to write. This may be for example a young child or someone learning a new language.
SUMMARY OF THE DISCLOSURE
[0007] It is the aim of embodiments of the present disclosure to address one or more of these problems.
[0008] According to an aspect of the present disclosure there is provided a tool for providing an image on a tape medium, said tool comprising means for inputting an image, means for providing said image on said tape medium, means for obtaining input image information from said input means, and sound generation means for using said information to provide an audible output in dependence on said input image.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
[0009] For a better understanding of the present disclosure and as to how the same may be carried into effect, reference will now be made by way of example to the accompanying drawings in which:
[0010] FIG. 1 shows an embosser embodying the present invention;
[0011] FIG. 2 shows part of the embosser of FIG. 1 in more detail, with no tape present;
[0012] FIG. 3 is a diagrammatic representation of the circuitry of the embosser of FIG. 1 ;
[0013] FIG. 4 is schematic view of the embosser of FIG. 1 showing its construction;
[0014] FIG. 5 shows a tape printer embodying the present invention;
[0015] FIG. 6 shows the cassette receiving bay of the tape printer of FIG. 5 with a cassette in place; and
[0016] FIG. 7 is a diagrammatic representation of the circuitry of the tape printer of FIG. 5 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0017] Reference is made to FIGS. 1 to 4 which show a hand operated embossing tool 10 . The tool 10 is designed to emboss selected indicia, such as characters, symbols, numbers or the like, on an elongated strip of embossable material such as a plastic tape 14 or the like. Some embodiments of the present invention are able to deal with more than one width of tape. Other embodiments of the present invention are arranged to deal with a single width of tape. In the embodiment shown in the Figures, precut lengths of tape are inserted into the tool and are embossed. Alternatively or additionally, he embosser can be used with a reel of tape. That reel may be external to the tool or in alternative embodiments of the present invention may be incorporated in the embosser. For example, in some embodiments of the present disclosure, the tape may be received in the handle of the embosser.
[0018] Embossing of the tape is accomplished at an embossing station 26 where there is located embossing means in the form of an embossing die set 28 actuated by a actuating member 30 . Die set 28 is one of a series of die sets located in a ring on a selector wheel 32 . The selector wheel 32 is rotatable about its central axis 33 and comprises an upper 35 and a lower wheel 37 . One part of a die set is on the upper wheel 35 and the other is arranged opposite thereto on the other wheel 37 . In particular, one of these wheels carries the die and the other of which carries the punch of each die set. In this way, any one of the series of die sets can be located at the embossing station 26 to emboss the selected indicia on the tape 14 .
[0019] As can be seen from FIG. 4 , the actuating member 30 is part of the handle 31 . When the handle in actuated, it pivots about point 53 causing the actuating member to move upwardly to move the part of the die set of the lower ring toward the upper ring.
[0020] The handle is additionally arranged to receive batteries 70 which are used to supply the circuitry illustrated in FIG. 3 .
[0021] Reference is made to FIG. 2 which shows the view from above of the embosser with no tape medium 14 being present. A switch 50 is provided. The switch 50 is a plunger switch. When tape medium is present, the plunger is depressed thus closing a contact. When no tape is present, the switch is open.
[0022] Reference is made to FIG. 3 which shows the circuitry for controlling the embosser. The switch 50 is connected to detection circuitry 60 which receives an input therefrom. In particular, the detection circuitry 60 determines whether or not the plunger switch 50 is depressed or not. If the switch is depressed, then the contact will be closed and it can be determined that tape is present. If, on the other hand, the switch is not depressed, the contact is open and the detection circuitry determines that no tape is present. Any other suitable mechanism may alternatively be used.
[0023] In preferred embodiments of the present invention, the voice generator 62 is arranged only to operate when the tape is present.
[0024] The circuitry comprises a character detector 64 which is arranged to detect which character or the like is at the embossing station. The underside of the wheel is coded with a coding ring 39 having metal strips. Six contacts 41 are provided. Depending on whether or not a contact 41 is in contact with a metal strip depends on whether or not a signal is provided. In this way, the output of the contacts 41 provides a binary output which is unique for each position of the wheel. This binary output is used by the detection circuitry 60 to identify the letter or the like at the embossing station. It should be appreciated that the character detector can be replaced by any other type of detector.
[0025] The detection circuitry 60 is arranged to use the information from the character detector 64 to determine which character or symbol has been selected. Also provided is a movement detector 66 which is arranged to determine when the handle has been activated to emboss a character on the tape. This is done by a switch 66 . When the handle is in its unactivated position, the switch is open. When the handle is squeezed, the switch is closed. Again any other suitable arrangement may be alternatively used.
[0026] The detection circuitry thus provides an output to a voice generator 62 identifying that a character is being embossed, that tape is present and the identity of the character. The voice generator 62 then provides an output to a speaker 68 and the speaker outputs the selected letter or the like. The voice generator may in some embodiments of the invention only provide an output if tape is present. However this is optional. The voice generator preferably only provides an output when the handle is activated and the image is embossed on the tape.
[0027] FIG. 5 shows a simplified plan view of a tape printing apparatus 102 . The tape printing apparatus 102 comprises a keyboard 104 . The keyboard 104 has a plurality of data entry keys and in particular comprises a plurality of numbered, lettered and punctuation keys 106 for inputting data to be entered as a label and function keys 108 for editing the input data. The keyboard 104 also comprises a print key 110 which is operated when it is desired that a label be printed as well as tape feeding keys 112 . Additionally, the keyboard 104 has an on/off key 114 for switching the tape printing apparatus 102 on and off. The function keys 108 allow the attributes of the label to be altered. For example, the function keys 108 can control the size or font of the input data, underlining, boxing or the like.
[0028] The tape printing apparatus 102 also has a liquid crystal display 118 which displays the data as it is entered. The display 118 allows the user to view all or part of the label to he printed which facilitates the editing of the label prior to its printing. Additionally, the display 118 can also display messages to the user, for example, error messages or an indication that the print key 110 should be pressed. The display 118 is driven by a display driver 128 which can be seen in FIG. 7 . In certain embodiments of the present invention, the display can be omitted.
[0029] On the underside of the tape printing apparatus 102 , which can be seen from FIG. 6 , there is a cassette receiving bay 140 . The cassette receiving bay 140 includes a thermal printhead 142 and a platen 144 which cooperate to define a print zone 146 . The printhead 142 is pivotable about a pivot point 148 so that it can be brought into contact with the platen 144 for printing and moved away from the platen 144 to enable a cassette to be removed and replaced. A cassette inserted into the cassette bay 140 is denoted generally by reference numeral 150 . The cassette 150 holds a supply spool 152 of image receiving tape 154 . The image receiving tape 154 comprises an upper layer for receiving a printed image on one of its surfaces and has its other surface coated with an adhesive layer to which is secured a releasable backing layer. The image receiving tape 154 is guided by a guide mechanism (not shown) through the cassette 150 , out of the cassette 150 through an outlet O, past the print zone 146 to a cutting location C. The same cassette 150 also has an ink ribbon supply spool 156 and ink ribbon takeup spool 158 . The image receiving tape 154 and ink ribbon 160 are arranged to pass in overlap between the printhead 142 and the platen 144 . In particular, the image receiving layer of the image receiving tape 154 is in contact with the ink ribbon 160 .
[0030] The platen 144 is driven by a motor 130 (see FIG. 7 ), for example a DC motor or a stepper motor no that it rotates to drive the image receiving tape 154 in a direction which is parallel to the lengthwise extent of the image receiving tape 154 through the print zone 146 . In this way, an image is printed on the image receiving tape 154 and the image receiving tape is fed from the print zone 146 to the cutting location C provided at a location on a portion of the wall of the cassette 150 which is close to the print zone 146 . The portion of the wall of the cassette 150 where the cutting location C is defined is denoted by reference 162 . A slot 164 is defined in the wall portion 162 and the image receiving tape 154 is fed past the print zone 146 to the cutting location C where it is supported by facing wall portions on either side of the slot 164 .
[0031] A cutting mechanism 166 s provided and includes a cutter support member 168 which carries a blade 170 . The blade 170 cuts the image receiving tape 154 and enters the slot 164 .
[0032] In those embodiments where the motor 130 is a DC motor, the image receiving tape 154 is driven continuously through the print zone 146 during printing. Alternatively in those embodiments where the motor is a stepper motor, the platen 144 rotates stepwise to drive the image receiving tape 154 in steps through the print zone 146 during the printing operation.
[0033] The print head 142 is a thermal printhead comprising a column of a plurality of printing elements which are selectively activatable in dependence on the image to be printed. The printhead 142 is preferably only one printing element wide and the column extends in a direction perpendicular to the lengthwise direction of the image receiving tape 154 . The height of the column of printing elements is preferably equal to the width of the image receiving tape 154 to be used with the label printing apparatus 102 . Where more than one width of image receiving tape 154 is used, the printhead column has a height equal to the largest width of tape 154 . An image is printed on the image receiving tape 154 column by column by the printhead 142 .
[0034] The printhead 142 has a printing cycle having a first part (strobe type) in which the selected printing elements are activated and a second part in which none of the printing elements are activated.
[0035] As an alternative to the one cassette system shown in FIG. 6 , the cassette receiving bay may be arranged to receive a separate image receiving tape cassette and a separate ink ribbon cassette which are arranged so that the ink ribbon and image receiving tape are passed in overlap through a print zone. This particular cassette arrangement is described for example in our European Patent Application No 578372, the contents of which are herein incorporated by reference. Any other suitable arrangement for providing a supply of image receiving tape can of course be used with embodiments of the present invention.
[0036] FIG. 7 shows the basic control circuitry for controlling the tape printing apparatus of FIGS. 5 and 6 There is a microprocessor chip 120 having a read only memory (ROM) 122 , a microprocessor 124 and random access memory capacity indicated diagrammatically by RAM 126 . The microprocessor 124 is controlled by programming stored in the ROM 122 and when so controlled acts as a controller. The microprocessor chip 120 is connected to receive label data input to it from the keyboard 104 . The microprocessor 120 outputs data to drive the display 118 via the display driver chip 128 to display a label to be printed (or apart thereof) and/or a message or instruction for the user. The display driver chip 128 may be incorporated in the microprocessor chip 120 . Additionally, the microprocessor chip 120 also outputs data to drive the printhead 142 which prints an image onto the image receiving tape 154 to form a label. The data output to the printhead 142 defines which of the printing elements are to be activated and the duration of the first part of the printing cycle. Finally, the microprocessor chip 120 also controls the motor 130 for driving the image receiving tape 154 through the tape printing apparatus 102 . The microprocessor chip 120 may also control the cutting mechanism 166 to allow lengths of image receiving tape 154 to be cut off after the image has been printed thereon. It should be appreciated that the cutter mechanism can alternatively be manually operated.
[0037] It should be appreciated that in alternative embodiments of the present invention, an image can be printed directly onto a thermally sensitive image receiving tape, thus avoiding the need for an ink ribbon.
[0038] The microprocessor 124 comprises a voice generation processor 143 . The voice generation processor may be part of the microprocessor 124 or may be provided by a separate processor. If the voice generation processor 143 is provided by a separate processor, that may be provided on a different integrated circuit to the microprocessor 124 . The voice generation processor 143 is arranged to receive information from the keyboard 104 , via the microprocessor 124 in preferred embodiments of the present invention, identifying the key which has been pressed. The microprocessor 124 may be arranged to receive the information from the keyboard 104 and identify the key which has been pressed.
[0039] For those keys associated with characters or letters, the associated letter or character is identified. Information identifying the character or number is output to the voice generation processor 143 which outputs a signal to a speaker 117 . The speaker 117 thus outputs the letter or number which has been activated by the user. Thus, if the user presses a key for the letter “K” the speaker will broadcast the sound of the letter “K”.
[0040] Additionally or alternatively, the functions selected using the keys 108 may be also output by the speaker 117 . For example, the speaker 117 may say that there is a “box” when boxing is selected, indicate the font, size of font or the like. | A tape printer for providing an image on a tape medium, the tape printer permitting inputting an image; providing the image on the tape medium; obtaining input image information; and using the input image information to provide an audible output in dependence on the input image. | 1 |
RELATED APPLICATIONS
This application is a continuation of U.S. application Ser. No. 12/415,808 filed Mar. 31, 2009 which claims priority to U.S. provisional application No. 61/040,952, entitled “Adjustable Ergonomic Chair” and filed Mar. 31, 2008, and hereby incorporates the same by reference, and to U.S. provisional application No. 61/165,307, entitled “Adjustable Task Chair” and filed on Mar. 31, 2009, and hereby incorporates the same by reference.
FIELD
The invention relates to chairs or supports, and more specifically to chairs in which the user's back and knees are supported with respect to the chair seat to enhance the anatomical, physiological and psychological support afforded to the user by the chair.
BACKGROUND
Many people spend the substantial part of their workday sitting in a task chair at a desk or table. Therefore, properly designed task chairs and posture are important for the comfort and health of many people. To this end, many different task chairs have been devised.
Many designs are directed towards adjustability, weight distribution and style but few designs ensure that the user is sitting properly in the chair. One such design is the so-called kneeling chair, where the seat is at a forward angle such that the knees are lower than the hips and the thighs are at an angle of about 60 to 70 degrees from vertical, and some weight is borne by the knees. Another such design is described in U.S. Pat. No. 6,086,157 to Toso, entitled “Ergonomic Chair” and hereby incorporated by reference. This design incorporates a horizontal seat, a back brace and a knee brace, which are adjustable with respect to each other. This design ensures proper posture because the knee brace prevents slouching or other incorrect posture. Another solution to this problem may be found in U.S. Pat. No. 4,773,106 to Toso et al., entitled “Back Support” and hereby incorporated by reference, which is directed to a back support strap that permits the wearer to sit in an upright position for extended periods of time by tensioning the strap against the knees to support the wearer's back.
There is thus an ongoing need to develop ergonomic task chairs that provide comfort and proper positioning.
SUMMARY
One embodiment pertains to an ergonomic task chair which maintains a seated person in an erect position in order to aid in relieving stress in the back while seated. The ergonomic task chair includes a seat portion, a back brace portion and a knee brace portion. The ergonomic task chair also includes struts to connect the knee brace and the back brace to the seat such that the knee brace and the back brace automatically adjust from a first position to a second position when a person sits in the task chair. The first position is a position where the back brace and the knee brace are spread out from each other to permit easy access to the chair and the second position is a position when the back brace and knee brace are closer together. In the second position, the back brace applies pressure to the lower back of the seated person and the knee brace applies pressure to the knees or upper shins of the seated person to help maintain an optimal seated posture for the seated person.
The chair may include a back in which the back brace is disposed. In some embodiments, the back includes an upper back portion and a lower back portion and the back brace is disposed between the upper back portion and the lower back portion. Some embodiments may include arm rests, which may be adjustable. In some embodiments the chair is disposed on a wheeled or footed base. The base may have five feet or wheels and may include a hydraulic arm or other system to adjust the height of the seat to customize the chair to an individual. The back brace may be attached by a telescoping mechanism to allow the user to adjust the height of the back brace relative to the seat. Likewise the knee brace may be attached by a telescoping mechanism to allow the user to adjust the forward distance of the knee brace with respect to the seat. A button, lever or other mechanism may be included to lock the chair in the first position.
The knee brace may include a left knee brace and a right knee brace, which may pivot to the sides of the chair to allow easier access to the seat and to allow the chair to be used as a regular task chair when desired.
In some embodiments, the seat is suspended above and spaced apart from the base, which base is connected to a top platform. One or more struts from the back brace are pivotably connected to the front of the platform and slideably and pivotably connected to the bottom of the front of the seat. In a similar fashion, one or more struts from the knee braces are pivotably connected to the rear of the platform and slideably and pivotably connected to the rear of the bottom of the seat. This connection arrangement fixes the seat above and spaced apart from the platform and allows the back brace and knee braces to close into position when a user sits in the chair. The back brace may be pivotably connected to the back brace struts and the knee braces may likewise be pivotably connected to the knee brace struts.
One embodiment pertains to an ergonomic task chair having a front and a rear that includes a laterally extending seat having a front and a rear, a back brace disposed above the rear of the seat, and a knee support disposed in the front of the chair, wherein the back brace and the knee support have a first position where there is a first minimum distance between the back brace and the knee support and a second position where there is a second minimum distance between the back brace and the knee support, the second minimum distance being less than the first minimum distance, wherein movement from the first minimum distance to the second minimum distance is triggered by a downward movement of the seat.
Some embodiment pertains to a task chair as described above and further including a platform disposed beneath and spaced apart from the seat, the platform having a front and a rear, a back brace strut, a knee brace strut, wherein the back brace strut is connected to the back brace, the platform and the seat, and wherein the knee brace strut is connected to the knee brace, the platform and the seat. Some embodiments pertain to a task chair as described above and wherein the back brace strut is connected to the front of the platform and the front of the seat and wherein the knee brace is connected to the rear of the platform and the rear of the seat. Some embodiments pertain to a task chair as described above and wherein the back brace strut is connected to the platform by a first joint that allows the back brace strut to pivot about a first axis with respect to the platform and wherein the knee brace strut is connected to the platform by a second joint that allows the knee brace strut to pivot with respect to the platform about a second axis.
Some embodiments pertain to a task chair as described above and wherein the back brace strut is connect to the seat by a first joint that allows the back brace strut to pivot with respect to the seat about a first axis and to slide with respect to the seat along a second axis and wherein the knee brace strut is connect to the seat by a second joint that allows the back brace strut to pivot with respect to the seat about a third axis and to slide with respect to the seat along a fourth axis.
Some embodiments pertain to a task chair as described above and wherein the back brace is biased to the first position.
Some embodiments pertain to a task chair as described above and wherein the back brace is biased to the first position by a hydraulic cylinder.
Some embodiments pertain to a task chair as described above and wherein the back brace is biased to the first position by a spring.
Some embodiments pertain to a task chair as described above and wherein the knee brace is biased to the first position.
Some embodiments pertain to a task chair as described above and wherein the back brace is pivotably connected to the back brace strut.
Some embodiments pertain to a task chair as described above and wherein the knee brace is pivotably connected to the knee brace strut.
Some embodiments pertain to a task chair as described above further including a back disposed above the rear of the seat portion wherein the position of the back relative to the seat portion does not change between the first position and the second position.
Some embodiments pertain to a task chair as described above and wherein the back comprises an upper back portion and a lower back portion and wherein the back brace is disposed between the upper back portion and the lower back portion where in the first position.
Some embodiments pertain to a task chair as described above and further including a second back brace strut connected to the back brace, the platform and the seat.
Some embodiments pertain to a task chair as described above and wherein the knee brace is a left knee brace and further comprising a right knee brace and a second knee brace strut, the knee brace strut connected to the left knee brace and the second knee brace strut connected to the right knee brace.
Some embodiments pertain to a task chair as described above and wherein the knee brace strut includes a hinge such that the left knee brace can be moved from a position in front of the seat to a position that is to the left of the first position and wherein the second knee brace strut includes a hinge such that the right knee brace can be moved from a position in front of the seat to a position that is to the right of the first position.
The above summary of some example embodiments is not intended to describe each disclosed embodiment or every implementation of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention may be more completely understood in consideration of the following detailed description of various embodiments in connection with the accompanying drawings, in which:
FIG. 1 is a diagrammatic isometric view of an adjustable task chair 10 in accordance with one embodiment of the invention in a first position;
FIG. 2 is a diagrammatic isometric view of an adjustable task chair 10 in accordance with one embodiment of the invention in a second position;
FIG. 3 is a diagrammatic right side view of an adjustable task chair 10 in accordance with one embodiment of the invention in a first position;
FIG. 4 is a diagrammatic right side view of an adjustable task chair 10 in accordance with one embodiment of the invention in a second position;
FIG. 5 is a diagrammatic front view of an adjustable task chair 10 in accordance with one embodiment of the invention in a first position;
FIG. 6 is a diagrammatic front view of an adjustable task chair 10 in accordance with one embodiment of the invention in a second position;
FIG. 7 is a diagrammatic isometric view of an adjustable task chair 10 in accordance with one embodiment of the invention in a first position;
FIG. 8 is a diagrammatic isometric view of an adjustable task chair 10 in accordance with one embodiment of the invention in a first position;
While the invention is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit aspects of the invention to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.
DETAILED DESCRIPTION
For the following defined terms, these definitions shall be applied, unless a different definition is given in the claims or elsewhere in this specification.
All numeric values are herein assumed to be modified by the term “about”, whether or not explicitly indicated. The term “about” generally refers to a range of numbers that one of skill in the art would consider equivalent to the recited value (i.e., having the same function or result). In many instances, the term “about” may be indicative as including numbers that are rounded to the nearest significant figure.
The recitation of numerical ranges by endpoints includes all numbers within that range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5).
Although some suitable dimensions ranges and/or values pertaining to various components, features and/or specifications are disclosed, one of skill in the art, incited by the present disclosure, would understand desired dimensions, ranges and/or values may deviate from those expressly disclosed.
As used in this specification and the appended claims, the singular forms “a”, “an”, and “the” include plural referents unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term “or” is generally employed in its sense including “and/or” unless the content clearly dictates otherwise.
The following detailed description should be read with reference to the drawings in which similar elements in different drawings are numbered the same. The detailed description and the drawings, which are not necessarily to scale, depict illustrative embodiments and are not intended to limit the scope of the invention. The illustrative embodiments depicted are intended only as exemplary. Selected features of any illustrative embodiment may be incorporated into an additional embodiment unless clearly stated to the contrary.
Referring now to FIGS. 1-8 , an adjustable task chair 10 is shown from various perspectives as described above. FIGS. 1 , 3 , 5 , 7 and 8 illustrate the chair in a first position, which is the position that the chair 10 will generally assume when empty. FIGS. 2 , 4 and 6 illustrate the chair in a second position, which is a position the chair may assume when someone is sitting in the chair (the user is not illustrated). The reference directions used herein will be from the perspective of one sitting in the chair as it is intended to be sat in. It is from this perspective that terms such as front, rear, left, right, raise, lower, up, down and the like should be understood.
The chair 10 includes a seat 12 that extends generally laterally, a back brace 14 and one or more knee braces 16 and 18 . While embodiments are contemplated where a single knee brace extends across the front to accommodate a pair of knees, the embodiment illustrated includes a left knee brace 16 and a right knee brace 18 . The back brace may be integrated into a back 20 . The back 20 does not move with the back brace from the first position to the second position and thus, during seating, is fixed with respect to seat 10 . Back 20 , nevertheless, may be other adjustable with respect to seat 12 to accommodate particular users and particular adjustments to the back brace 14 . Back 20 may include an upper back portion 22 and an lower back portion 24 where the back brace 14 is disposed between the upper and lower back portions as illustrated. In some embodiments, a button or lever is included that can be operated to lock the chair into the first position or, in other embodiments, into any desired position so that the chair may be used as a typical task chair.
Back brace 14 is attached to the rest of chair 10 through one or more back brace struts 32 . In the embodiment illustrated, two back brace struts 32 are illustrated which are disposed symmetrically about a plane between the left and right halves of the chair. It can be appreciated, however, that other configurations for attaching the back brace to the rest of chair 10 using one or more back brace struts are possible. For example, a single back brace strut 32 may be disposed along the plane described above. Back brace 14 may be pivotably connected to back brace struts 32 and may be biased by springs or another mechanism (not shown) to a default position. Back brace struts 32 may also include a telescoping portion (not shown) to allow a user to raise or lower the back brace 14 to a desired height.
Left and right knee braces 16 and 18 are connected to the rest of the chair 10 using left and right knee brace struts 34 and 36 , respectively. Each strut may include a hinge to allow the left and right knee braces to swing out to provide easier access to the seat as illustrated in FIGS. 7 and 8 . Hinge 46 in right knee brace strut 36 may be seen in several of the views. Hinge 46 may include one or more detents to fix the struts in certain desired positions. For example, one detent may fix the struts in the position shown in FIG. 7 and, in other embodiments, another detent may fix the struts in the position shown in FIG. 8 . An appropriate degree of lateral force may allow a user to over the force of the detent to move the struts between positions. Left and right knee braces may also include telescoping portions (not shown) to allow a user to lengthen or shorten the struts to accommodate a particular user.
A chair base 26 may include wheels 28 and may be of any suitable configuration. For example, the chair base 26 illustrated includes five wheels 28 on arms extending radially out from a central hub. On top of chair base 26 is a platform 30 , which may be seen in FIGS. 3 , 4 , 7 and 8 . Platform 30 may be connected to chair base 26 with a hydraulic cylinder 48 or other suitable mechanism for adjusting the height of the seat 12 and other portions of the chair above the cylinder by the use of a lever (not shown).
Struts 32 , 34 and 36 may be connected to the chair and the platform in the following manner. As can be seen, for example, in FIG. 3 , back brace struts 32 curve or bend around the bottom of seat 12 and are attached to seat 12 near the front of the seat. The connections between back brace struts 32 and seat 12 allow for lateral movement in a front to back direction and pivoting about an axis extending parallel to the front of the seat 12 . When the chair is in the first position, the back brace struts are towards the rear of their lateral freedom of movement in the connection. As can be better send in FIG. 7 , the back brace struts 32 are attached to the platform 30 in the front portion of platform 30 . Element 50 is a hinge that allows pivoting of the back brace struts with respect to platform 30 . Element 50 may be a simple hinge or may be a hinge biased to keep back brace 14 in the first position. Element 50 may be biased by the inclusion of a spring or hydraulic element as desired. In some embodiments, an additional biasing element is not needed to move the chair into the first position. The back brace 14 and the back brace struts 32 are substantially to the rear of the pivot connection with the platform 30 . Likewise, the knee braces and the knee brace struts are substantially to the front of their pivot connections with platform 30 . The weight of the configuration, therefore, may be sufficient to move the chair to the first position when empty.
Knee brace struts 34 and 36 similarly curve or bend around the bottom of seat 12 to connect to the rear of seat 12 as shown in FIG. 3 . The connections between struts 34 and 36 and seat 12 allows for lateral movement in a front to back direction and pivoting about an axis extending parallel to the rear of the seat 12 . When the chair is in the first position, the knee brace struts are towards the front of their lateral freedom of movement in the connection. Knee brace struts are pivotably connected to the rear of platform 30 at joints 52 as can be best seen in FIG. 8 .
The chair 10 may also include armrests 54 , which may be adjustable to fit the user, and which may be attached to the seat as illustrated.
The chair may be manufactured in any desired manner as is known in the art. For example, the chair may include fabrics, meshes, foam, batting, metal and polymer parts as appropriate and desired and may be fabricated using any conventional manufacturing techniques.
In use, a user may open the knee brace struts 34 and 36 as illustrated in FIG. 8 and move so the back of the knees are near the front edge of the seat 12 . The user may then close the knee brace struts 34 and 36 to the position shown in FIG. 7 and sit in the chair. The weight of the user will cause both the back brace 14 and the knee braces 16 and 18 to rotate inward towards the user. The back brace will contact the user's back and the knee braces will contact the users knees and urge the user into an erect sitting position, where pressure from the back brace and the knee braces will support the user in the erect sitting position.
Those skilled in the art will recognize that the present invention may be manifested in a variety of forms other than the specific embodiments described and contemplated herein. Accordingly, departure in form and detail may be made without departing from the scope and spirit of the present invention as described in the appended claims. | An ergonomic task chair having a front and a rear, including a laterally extending seat having a front and a rear, a back brace disposed above the rear of the seat, and a knee support disposed in the front of the chair, wherein the back brace and the knee support have a first position where there is a first minimum distance between the back brace and the knee support and a second position where there is a second minimum distance between the back brace and the knee support, the second minimum distance being less than the first minimum distance, wherein movement from the first minimum distance to the second minimum distance is triggered by a downward movement of the seat. | 0 |
CROSS-REFERENCES TO RELATED APPLICATIONS
This application claims the benefit of German patent application DE19917968.9, filed Apr. 21, 1999, herein incorporated by reference.
FIELD OF THE INVENTION
The present invention relates to a service unit for textile machines which wind yarn into a cheese, in particular open-end spinning machines, and relates more particularly to a service unit having manipulation devices for repairing ordinary yarn breaks and having an auxiliary yarn feeding device for piecing the yarn being wound following an exchange of an empty tube for a finished cheese.
BACKGROUND OF THE INVENTION
Such service units are known to be employed in connection with open-end spinning machines as disclosed, for example, in German Patent Publications DE 44 43 818 A1, DE 38 01 964 A1, DE 42 44 081 A1 or DE 44 04 538 A1.
The service units described in these patents service the numerous work stations of the open-end spinning machines, i.e. they act autonomously in case a need for a service operation or action occurs at one of the work stations. Such a need arises, for example, if a yarn break has occurred at one of the work stations, or if a cheese at one of the work stations has attained its prescribed full diameter and must be exchanged for an empty tube.
In such case, the service unit moves to an operative position at the respective work station and, in case of an ordinary yarn break, i.e., a yarn break occurring during the course of winding the cheese to its prescribed diameter, the service unit actuates a yarn searching nozzle to locate and aspirate the torn yarn end lying on or extending from the circumferential surface of the cheese. The yarn end is prepared for continuation of the spinning process and, after the spinning rotor has been cleaned, the yarn end is reinserted into the spinning box of the work station.
In the case of the service units known from German Patent Publications DE 44 43 818 A1 or DE 38 01 964 A1, the prepared yarn end is attached to a fiber ring formed from individual fibers, which rotates along with the spinning rotor, while with the service units in accordance with German Patent Publications DE 42 44 081 A1 or DE 44 04 538 A1 the delivery of fibers to the spinning rotor from the sliver opening device is first completely rerouted and is only re-fed to the fiber collecting surface of the spinning rotor after conditions are appropriate for resuming the spinning operation.
Since a pieced portion of a yarn should differ as little as possible from the remaining extent of the yarn as normally spun by the spinning rotor in regard to the appearance as well as the strength of the pieced portion of yarn, various setting parameters, for example the number of revolutions at the spinning start, the feed-in of the fiber end and the yarn retraction, should be exactly maintained. It is therefore known to check after each piecing operation whether the yarn profile in the area of the piecing device falls within preset acceptable values. Thus, the values determined during the check of the piecing operation can be processed, as described in German Patent Publication DE 196 49 314 A1, in a control device of the service unit in such a way that subsequent yarn piecings are optimized. Here, the optimization of the yarn piecing is performed by means of a defined small change of one or several of the setting parameters which are responsible for the condition of the yarn piecing.
This service process becomes somewhat more difficult when an empty tube must be exchanged for a full finished cheese and a fresh spinning process must be started thereafter. In this case, following the ejection of the finished cheese and the insertion of an empty tube, an auxiliary yarn is initially provided by an auxiliary yarn feeding device arranged in the service unit.
As described, for example, in German Patent Publication DE 44 43 818 A1, the auxiliary yarn, which extends between the mouth of the feed tube of the auxiliary yarn feeding device and the yarn search nozzle, is used for piecing by the yarn piecing devices of the service unit. Thus, the auxiliary yarn is first positioned in front of a yarn catching plate and is transferred to the yarn feeding device by a yarn draw-in device. Subsequently the auxiliary yarn, which is gripped in feeding tongs of the yarn feeding device, is cut by means of a yarn cutting device, and the severed yarn end is removed by the yarn search nozzle via suction. The end of the auxiliary yarn end gripped in the feeding tongs of the yarn feeding device is finally prepared in a customary manner, transferred by the forward pivoting yarn feeding device to the spinning box of the appropriate work station of the open-end spinning machine and is threaded into a small yarn withdrawal tube of the spinning box. Shortly before the auxiliary yarn is placed into the rotating spinning rotor against the ring of individual fibers therein, the auxiliary yarn feeding device is switched to suction air and the auxiliary yarn is cut by a yarn cutting device.
Thereafter the auxiliary yarn and the freshly spun yarn are drawn off by means of the yarn withdrawal device of the service unit and aspirated into the feed tube of the auxiliary yarn feeding device. Then a length of yarn including the auxiliary yarn and the reattached piecing of spun yarn are cut off by a yarn cutting device arranged in the area of the feed tube, and the freshly spun yarn is placed against an empty winding tube maintained between the tube plates of the bobbin creel of the respective work station.
Since the auxiliary yarn used by the above described service units often is not identical with the yarn to be subsequently produced, for example in case of the start of a batch, problems can sometimes arise in the course of the piecing process.
SUMMARY OF THE INVENTION
In view of the above mentioned prior art, it is an object of the present invention to improve the known service units, which have proven satisfactory in basic operation, in respect to their piecing dependability and, in particular, with respect to piecing by means of an auxiliary yarn.
In accordance with the present invention, the piecing process, which per se is always somewhat critical, is made less critical, especially in those cases where the pieced yarn extent will be later removed anyway, in that a pieced yarn portion is produced according to operational parameters of the piecing process which are changed from the parameters conventionally observed. The changed operational parameters for the piecing process differ in part quite clearly from the operational parameters of a normal yarn piecing made optimally according to conventional practices. By changing the operational parameters, it is possible in a simple and dependable manner to produce a visually less beautiful, but extremely durable so-called “safety” pieced yarn extent.
In a preferred embodiment, the operational parameters for a safety pieced yarn extent can be corrected at any time and, if necessary, can also be newly set later, for example manually. In this manner, it is possible to react promptly to any contingencies and in particular to improve the strength of any failed yarn piecings.
According to an advantageous feature of the invention, a first program stored in the control device of the service unit provides operational parameters for a piecing process to produce a yarn piecing which is almost identical to the yarn itself which is being pieced, while a second program also stored in the control device provides operational parameters for a piecing process to produce a yarn piecing which is primarily sturdy but whose visual appearance is of no importance. A service unit designed in this way produces the correct, i.e. optimal, yarn piecing for any occasion.
In a preferred embodiment, the operational piecing process parameters which can be changed for producing a safety yarn piecing are the number of revolutions of the spinning rotor during the piecing process, increasing the sliver feeding and/or elongating the operation of the piecing yarn retracting device. By lowering the number of revolutions of the spinning rotor during piecing, it is possible to reduce the yarn tension and therefore the stress acting on the pieced yarn extent in the process. An elongation of the yarn retraction leads to an extension of the winding zone between the fiber ring and the yarn end being pieced, which rotates with the spinning rotor, and the inserted yarn end. The number of fibers involved in the piecing process can be increased by a change in the sliver feeding operation, in particular by an increase of the sliver feeding rate, whereby the pieced yarn extent as a whole can be made sturdier as a result. These steps, individually or in combination, result in very sturdy safety yarn piecings, although they are not optimal in appearance.
Further features, details and advantages of the present invention will be understood from the following description of an exemplary embodiment of the present invention with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic side elevational view of one side of an open-end spinning machine with a traveling autonomously-operating service unit for servicing the work stations and, in particular, for performing the yarn piecing operation of the present invention,
FIG. 2 is a schematic side elevational view of the service unit in accordance with FIG. 1, the housing of which is broken away to show some of the essential yarn manipulating elements provided for piecing a yarn, and
FIG. 3 is a schematic side elevational view of the spinning station of the open-end spinning machine of FIG. 1 and the control device of the service unit of FIG. 2 with further manipulating and functional elements.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the accompanying drawings and initially to FIG. 1, one side of an open-end spinning machine, known per se, is represented schematically and identified in its entirety at 1. Spinning machines of this type have a plurality of work stations 2 , i.e., spinning stations, each of which is equipped with a spinning box 3 as well as with a winding device 4 for winding the yarn produced into a so-called cheese 8 . More specifically, a sliver 6 delivered from sliver storage cans 5 is fed into the spinning box 3 of each work station wherein the sliver is spun into yarn 7 which is then withdrawn from the spinning box 3 and wound into a cheese 8 at the winding device 4 . As represented, the winding devices 4 are equipped with a bobbin creel 9 for rotatably holding a yarn winding tube 10 on which the yarn is wound into the cheese 8 , and a winding drum 11 for peripherally driving the surface of the cheese or the empty tube. Typically, the open-end spinning machine also has a cheese transporting device 12 for removing finished cheeses 8 and transporting them to a collection location at the end of the spinning machine.
A service unit, for example a piecing carriage 16 , is mounted on or otherwise arranged in association with the spinning machine 1 for traveling movement therealong for performing servicing operations at the individual spinning stations as needed, e.g., the service unit may be supported on guide rails 13 , 14 , and on a support rail 15 for movement alongside the spinning stations. The running gear 17 of this piecing carriage 16 includes rollers 18 and a support wheel 19 . The piecing carriage 16 is supplied with electrical energy via a wiper contact arrangement 20 or any other suitable means, e.g., by a drag chain.
Such service units 16 can thusly move along the work stations 2 of the open-end spinning machine 1 and act independently when there is need for an action at one of the work stations 2 . Such need for action occurs, for example, when a yarn break has occurred at one of the work stations 2 , or if the cheese at one of the work stations has reached its predetermined diameter and must be exchanged for an empty tube. In such a case the service unit 16 travels to the respective work station, is positioned thereat and, in case of an ordinary yarn break, searches for the broken yarn end resting on the circumferential surface of the cheese 8 with its pivotably movable yarn suction nozzle 21 (FIG. 2 ).
As shown in FIG. 2, in addition to the pivotably seated yarn suction nozzle 21 , the service unit 16 has an expulsion and drive arm 22 having a drive roller 23 located at its end which can be placed against the cheese surface to eject a finished cheese 8 onto the transport device 12 . Moreover, the service unit 16 is equipped in a known manner with a yarn catch plate 25 , a yarn draw-in device 26 , a yarn feeding device 27 with feeding tongs 28 and a yarn cutting device 29 , as well as with a controllable yarn draw-off device 30 , 31 . In this case the yarn draw-off device comprises a draw-off roller 30 which is drivable in a defined manner, as well as a pivotably arranged pressure roller 31 . A creel opener 32 as well as a pressure lever 33 are integrated into the service unit 16 as further service elements. The service unit 16 furthermore has an auxiliary yarn transport device 34 , as well as a sliver draw-in arm 35 (FIG. 3 ), as well as a sensor device 39 (FIG. 3) for detecting the respective number of revolutions of the rotor.
The above described yarn manipulating devices as well as cleaning elements (not represented) of the service unit 16 are as a rule mechanically driven by means of cam disk packages, to which appropriate lever rods are connected.
The sliver draw-in arm 35 , whose movement is also controlled by means of a cam disk, has on its end a coupling sleeve 37 , which can be acted upon by means of a drive mechanism 36 in a defined manner. During the piecing process, the coupling sleeve 37 is positioned on a sliver infeed cylinder 38 of the open-end spinning device 3 .
As is customary, continuous monitoring of the rotational speed of a support disk 40 , and therefore of the number of revolutions with which the associated spinning rotor (not represented) rotates, takes place during a piecing process by means of the sensor device 39 which is connected to a control device 24 of the service unit 16 .
As can furthermore be seen from FIG. 3, the drive motor 36 of the sliver draw-in arm 35 is connected via a control line 41 , and the sensor device 39 is connected via a signal line 46 , to the control device 24 of the service unit 16 , while a drive motor 42 for a yarn withdrawal roller 30 is also connected via a control line 43 with the control device 24 .
The operation of the device in accordance with the present invention may thus be understood. As soon as the service unit 16 has determined or has been advised that there is need for action at one of the work stations 2 , for example by a data transmission system of the open-end spinning machine 1 , the service unit 16 travels to the respective work station 2 and is positioned thereat.
Thereupon, the service unit 16 either determines individually what type of error has occurred at the respective work station, for example an ordinary yarn break, a full cheese in need of exchanging, etc., or the data transmission system of the open-end spinning machine 1 communicates to the control device 24 of the service unit 16 the reason for calling the service unit 16 to the work station.
In case of an ordinary yarn break, the yarn end which has been wound onto the surface of the cheese is aspirated in a known manner by means of the suction nozzle 21 , is prepared for piecing, and is placed on a fiber ring which rotates along with the spinning rotor in the open-end spinning device 3 . The yarn which is subsequently withdrawn is wound on the cheese 8 .
In this case, a first program stored in the control device 24 of the service unit 24 controls the operational parameters of the piecing process such that the yarn piecing created has an appearance as well as strength values which are almost equal to that of the yarn itself. Moreover, measurements are taken of the created yarn piecing by means of a piecing check device 45 , the results of which measurements are processed in the control device 24 of the service unit 16 for further optimizing subsequent yarn piecings.
Once a cheese 8 has reached its prescribed diameter or a prescribed yarn length has been wound thereon, the cheese 8 must be exchanged for an empty tube 10 , whereupon the service unit 16 first ejects the finished cheese 8 onto the cheese transporting device 12 in a known manner by means of the expulsion and drive arm 22 and thereafter the service unit 16 places a fresh empty tube 10 into the bobbin creel 9 .
While the cheese transporting device 12 conveys the cheese 8 to a collection location arranged at the end of the machine, a piecing yarn is produced by means of the auxiliary yarn transport device 34 . This piecing yarn is prepared in a customary manner by the previously described yarn manipulating devices and is placed onto the fiber ring rotating together with the spinning rotor 4 in the open-end spinning device 3 .
Since the yarn piecing being created in the process is removed in every case prior to placing the yarn 7 against the empty tube 10 , the control device 24 operates in this case according to a second program which observes special operational parameters for producing a so-called “safety” yarn piecing which parameters differ clearly from the parameters followed for producing an ordinary yarn piecing which is approximately equal to the yarn itself.
Thus, for example, the control device 24 of the service unit 16 operating under this second program initiates an appropriate control of the drive mechanism 36 of the sliver draw-in arm 35 in the course of the sliver prefeeding E 2 to feed more fibers than usual into the spinning rotor, which results in a relatively thick, but more stable yarn piecing.
In place of or in additional to the increased sliver prefeeding E 2 , the second control program may also control the drive motor 36 to appropriately increase the length of time of its operation which achieves a so-called fiber addition (ΔE 3 ) thereby similarly resulting in a relatively thick, very durable safety piecing
Further setting parameters of the second control program may be to increase the yarn retracting length R 3 during the piecing process and/or to increase the number of revolutions of the spinning rotor during piecing, by means of which a safety piecing can be produced in a simple manner. For example, for increasing the yarn retracting length R 3 , the drive motor 42 of the yarn withdrawal roller 30 is controlled by the control device 24 of the service unit 16 in such a way that a slightly longer than normal yarn length is fed back into the spinning rotor. This increased yarn retraction length results in the yarn length as a whole involved in the piecing operation being slightly increased.
Since the respective number of revolutions of the spinning rotor during the piecing process is monitored by the sensor device 39 , and the piecing process is customarily initiated at a predetermined number of revolutions, it is also possible to affect the piecing by changing the predetermined number of revolutions for piecing. Thus, the control device 24 of the service unit 16 causes the sliver infeed, and correspondingly the yarn retraction, to be started at a number of revolutions which is clearly less than the number of revolutions for piecing customary for producing yarn piecings which are equal to the yarn. A safety piecing can also be produced in this manner while the risk of a faulty piecing can be clearly reduced.
As already previously explained, the above described steps result in yarn piecings which, although not visually attractive because they are not equivalent to the yarn, are extremely durable and in any event are cut out and removed prior to the yarn being fixed on the empty tube to resume the yarn spinning and winding process.
It will therefore be readily understood by those persons skilled in the art that the present invention is susceptible of broad utility and application. Many embodiments and adaptations of the present invention other than those herein described, as well as many variations, modifications and equivalent arrangements, will be apparent from or reasonably suggested by the present invention and the foregoing description thereof, without departing from the substance or scope of the present invention. Accordingly, while the present invention has been described herein in detail in relation to its preferred embodiment, it is to be understood that this disclosure is only illustrative and exemplary of the present invention and is made merely for purposes of providing a full and enabling disclosure of the invention. The foregoing disclosure is not intended or to be construed to limit the present invention or otherwise to exclude any such other embodiments, adaptations, variations, modifications and equivalent arrangements, the present invention being limited only by the claims appended hereto and the equivalents thereof. | A service unit ( 16 ) for a cheese-producing textile machine ( 1 ), in particular an open-end spinning machine, has manipulation devices for repairing ordinary yarn breaks, an auxiliary yarn transport device ( 34 ) for piecing yarn following a cheese/empty tube exchange, and a control device ( 24 ) storing a first program with optimal operating parameters for piecing an ordinary yarn break and a second program setting differing operating parameters for producing a safety piecing following a cheese/empty tube exchange. | 3 |
BACKGROUND OF THE INVENTION
[0001] The present invention concerns toiletries like soap for hand, body and surface use, as well as other cleaning products.
[0002] The amount of time needed to clean the skin or a surface has been researched extensively. The Association for Professionals in Infection Control and Epidemiology (APIC) Guideline for Hand Washing and Hand Antisepsis in Health - Care Settings (1995) (Table 1), recommends a wash time of 10-15 seconds with soap or detergent for routine hand washing for general purposes. The APIC recommends an antimicrobial soap or detergent or alcohol-based rub wash for 10-15 seconds to remove or destroy transient micro-organisms in for example, nursing and food preparation applications. The APIC further recommends an antimicrobial soap or detergent with brushing for at least 120 seconds for surgical applications. The US Centers for Disease Control and Prevention (CDC) recommends up to 5 minutes of hand cleaning for surgical applications. Clearly, the length of time spend washing the hands can have a great effect on eradication of microbes. Thus there is a need for a cleaning formulation that will enable the user to judge how long he has washed his hands in order to comply with the guidelines.
[0003] Proper hand washing habits are important for children also. Children in particular need guidance in determining the appropriate amount of time hand washing should be performed. This guidance is generally given by parents or other caregivers and, while important, is not omni-present. In addition to parental guidance, various other mechanisms have been used to encourage longer hand washing times in children. Soaps have been formulated as foams, for example, to increase the enjoyment children find in hand washing and thus to increase the amount of time children spend in washing. Fragrances have also been used to make the hand washing experience more enjoyable. Dual chamber vessels have been used to produce a color change upon the mixing of the components. It has also been suggested that the reactants in the dual chamber system may alternatively be kept together with one component inactive by some means, such as by microencapsulation, until sufficient physical stimulus results in their effective mixing, or that the components be kept separate yet in one container through the use of a non-miscible mixture of two phases. These methods, though possible, are somewhat impractical and expensive. Far simpler would be a system that produces a color change which does not rely on a physical or phase separation to keep the components unmixed.
[0004] There is a need for a color changing toiletry or cleaning product that will provide a time delayed indication that a predetermined cleaning interval has passed after dispensing. There is a further need for a toiletry that is also fun for children to use. There is a further need for the color changing chemistry to be made from components that may be pre-mixed and packaged together for later dispensing from a single chamber vessel.
SUMMARY OF THE INVENTION
[0005] In response to the difficulties and problems encountered in the prior art, a new composition has been developed which contains a base material and an indicator or color change agent that provides a change detectible by a user some time after dispensing, and which is stable in a single phase and suitable for storage in a single chamber dispenser. The detectible change may occur in from a finite time to at most about 5 minutes after dispensing, though the change generally does not occur until a second or more after dispensing. The change may occur in at between about 1 second and about 120 seconds, or more desirably between about 5 seconds and about 45 seconds, or still more desirably between about 15 and 35 seconds. The color change may occur in about 10 seconds. This color change composition may be added to toiletries such as soaps, skin lotions, colognes, sunscreens, shampoos, gels, toothpastes, mouthwashes and so forth as well as to other cleaning products like surface cleaners and medical disinfectants.
[0006] In another aspect, the invention includes a dispenser having a storage chamber and a dispensing opening in liquid communication therewith, and a cleaning composition within the storage chamber. The cleaning composition is a single phase mixture of a surfactant, a reactant and a dye and the cleaning composition changes color after being dispensed.
[0007] This invention also encompasses a hygiene teaching aid and a method of developing a hygiene habit. The hygiene teaching aid has an indicator that provides a change detectible to a user after a period of time after dispensing has passed. The method of developing a hygiene habit includes the steps of dispensing soap and water into a user's hands, rubbing the hands together until a change detectible to the user is detected, and washing the hands with water, where the soap contains an indicator that provides the change after a period of time after dispensing the soap into the hands has passed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a drawing of a pump type liquid soap dispenser.
[0009] FIG. 2 is a drawing of a foaming liquid soap dispenser using a pump.
[0010] FIG. 3 is a drawing of a pliable storage bottle for liquid soap which may be inverted for soap dispensing.
[0011] FIG. 4 is a drawing of a non-pliable, manually openable storage container for liquid soap.
[0012] FIG. 5 is a drawing of a pump type liquid soap dispenser suitable for wall mounting.
DETAILED DESCRIPTION OF THE INVENTION
[0013] The invention includes a base or carrier material such as a toiletry or cleaning product, and an indicator that provides a detectible change after a period of time, and that may be stably kept before use in a single closed vessel. It contains at least one dye or pre-dye and a modifying agent that causes a detectible change to occur. The detectible change may be, for example, in color or in shade or degree of color and changes in color may be from colorless to colored, colored to colorless, or from one color to another.
[0014] One method of producing the color change effect of this invention is by using color changing electrochemistry based on a reduction/oxidation or redox reaction, in the presence of a dye that is sensitive to this reaction; a redox dye. This reaction involves the transfer of electrons between at least one element or substance and another. In a redox reaction the element that loses electrons increases in valency and so is said to be oxidized and the element gaining electrons is reduced in valency and so is said to be reduced. Conversely, an element that has been oxidized is also referred to as a reducing agent since it must necessarily have reduced another element, i.e., provided one or more electrons to the other element. An element that has been reduced is also referred to as an oxidizing agent since it must necessarily have oxidized another element, i.e., received one or more electrons from the other element. Note that since redox reactions involve the transfer of electrons between at least two elements, it is a requirement that one element must be oxidized and another must be reduced in any redox reaction.
[0015] Reduction potential refers to the voltage that a redox reaction is capable of producing or consuming. Much effort has gone into the compilation of reduction potential for various redox reactions and various published sources, such as “Handbook of Photochemistry” by S. Murov, I. Carmichael and G. Hug, published by Marcel Dekker, Inc. N.Y. (1993), ISBN 0-8247-7911-8, are available to those skilled in the art for this information. The invention uses a reducing agent with sufficient redox potential to reduce a dye to a colorless state. Thus in the absence of such a reducing agent the dye, and by extension the base material, would remain the same color before and after use. A successful redox reaction for the practice of the invention should use components having a potential in the range of +0.9 to −0.9 volts. Oxygen, for example, has a redox potential of +0.82 volts.
[0016] Oxygen is poorly soluble in water and other materials like, for example, liquid soap formulations. There is normally, therefore, insufficient oxygen in the liquid to oxidize the colorless dye back to the colored state. It is known that the maximum concentration of oxygen in water at room temperature is approximately 13 parts per million (ppm), and, in the practice of the invention, this trace amount is consumed rapidly by the vastly greater amount of reducing agent. As a result, in a stationary, capped bottle, the dye in the liquid formulation will remain in the reduced or colorless state. When a small amount of the liquid formulation is used by placing it on the hands and by hand-washing action, for example in the case of hand soap, it is spread over a large surface area of the skin. This causes the oxygen concentration in this very thin film coating to exceed the concentration that the reducing agent can handle, allowing the dye to be oxidized and the color to develop in the desired indicator time period. Adjusting the concentration of the reducing agent and dye allows the modification of the desired time period from dispensing to color change.
[0017] This phenomenom is also observable by vigorously shaking a closed containing having a base material, such as a liquid soap formulation, and the color change indicator of this invention. When this is done, a color is developed due to the increased concentration of oxygen in the liquid soap. This color dissipates slowly after the container is allowed to rest as the oxygen slowly leaves the liquid soap. The reducing agent eventually overcomes the oxygen concentration in the liquid soap and reduces the oxidized dye back to the colorless state.
[0018] In one aspect of the invention, therefore, a redox reaction is triggered when the base material containing the color change composition of this invention is mixed with the air. It is the reaction with the oxygen in the air that is the primary reaction that begins the color change. In the case of a liquid hand soap, as discussed above for example, the action of rubbing the hands together results in mixing air into the soap to begin the reaction. In the redox reaction with oxygen, the oxygen is reduced and the dye is oxidized. As shown below (e.g. Example 1), this primary redox reaction results in a direct change in color, such as those reactions using a reducing agent and dye where the dye is a redox dye. When the color change composition is in storage, the redox dye is kept in its unoxidized state by the action of the reducing agent reacting with the available oxygen. Once the composition is in contact with an excess of oxygen such as when it is dispensed, the reducing agent is exhausted through oxidation and the redox dye then takes part in the oxidation, producing the color change.
[0019] This aspect of the invention, as discussed above, includes a redox dye and a reducing agent. These components are elaborated upon as follows:
[0020] Redox Dyes
[0021] Redox dyes include but are not limited to Food Blue 1, 2 and Food Green 3, Basic Blue 17, resazurin, FD&C Blue No. 2, FD&C Green No. 3,1,9-dimethyl methylene blue, and saframine O. Suitable dyes include but are not limited to members of the thiazine, oxazines, azine and indigo dye classes. Other redox dye candidates have been identified allowing the following color changes to occur with this system:
Colorless to blue Basic Blue 17 Colorless to red Resazurin (low dye concentration) Yellow (similar in color to FD&C Green No. 3 Dial liquid soap) to green Yellow to purple 1,9-dimethyl methylene blue Yellow to red Resazurin (higher dye conc.) Yellow to pink Saframine O
[0022] Food grade dyes were evaluated as dye candidates in the reducing agent/redox dye color change liquid soap formulation and a variety of color changing chemistries are available. The results of this evaluation may be seen in Example 6.
[0023] The amount of dye used in the practice of the invention is desirably between about 0.001 and 0.5 weight percent, more desirably between about 0.002 and 0.25 weight percent dye and still more desirably between about 0.003 and 0.1 weight percent.
[0024] Reducing Agents
[0025] Reducing agents include but are not limited to any compound that is compatible with the redox dye and base material being used and which will react with oxygen in a redox reaction. Upon mixing the base material, dye and reducing agent, the reducing agent reduces the dye to the colorless “reduced dye”. The base material will generally have a small amount of dissolved oxygen already present, and this oxygen reacts (oxidizes) with the “reduced dye” to form the colored dye. This is quickly re-converted back to the reduced form (colorless) by the high concentration of the reducing agent present in the formulation. The oxygen is therefore consumed in the formulation and converted, eventually, to water. The formulation therefore has essentially no oxygen present in it. This equilibrium may be represented as follows:
[0026] In the case of a liquid soap formulation, for example, on dispensing the soap onto the hand(s) and conducting hand-washing action, the soap is spread out over the hands as a thin layer and diluted with water. This action allows atmospheric oxygen to penetrate this thin layer and oxidize the dye to the colored state. The reducing agent reduces this dye to an extent but is eventually overwhelmed by the excess amount of atmospheric oxygen introduced by virtue of the large exposed surface area, and is consumed, allowing the dye to remain colored. This color formation gives the visual indication that sufficient hand-washing time has occurred. The “battle” of oxygen against reducing agent for the dye takes a finite time, thus allowing control of the hand-washing period for indicating purposes.
[0027] When a liquid soap formulation containing the inventive composition in a container is shaken, oxygen is introduced into the soap. The oxygen converts the colorless “reduced dye” to the colored form, but due to the solubility of oxygen in water being only about 13 parts per million (ppm) the oxygen is rapidly consumed in converting some of the dye. This colored oxidized dye is reduced by the larger concentration of reducing agent and the soap quickly becomes colorless once more. With repeated vigorous shake-cycles it may be possible to consume the reducing agent entirely, in which case the soap would remain colored.
[0028] Reducing agents suitable for producing a redox reaction upon exposure to the oxygen in air include but are not limited to sugars like glucose, galactose and xylose and so forth. Other suitable reducing agents include but are not limited to hydroquinone, ascorbic acid, cysteine, dithionite, ferric ion, copper ion, silver ion, chlorine, phenols, permanganate ion, glucothione, iodine and mixtures thereof. Metal complexes that can function as reducing agents are also suitable for the practice of this invention. Metal complexes include but are not limited to mononuclear, binuclear and cluster complexes like iron protoporyphyrin complexes and iron-sulfur proteins.
[0029] The reaction rates are different for the same amount by weight of different reducing agents and this may be an additional method of modifying the color change to the desired time period. Various sugars were evaluated as reducing agents and the results of this evaluation may be seen in Example 6.
[0030] The amount of reducing agent used in the practice of this invention is desirably between about 0.1 and 2.0 weight percent, more desirably between about 0.2 and 1.50 weight percent and still more desirably between about 0.3 and 1 weight percent. It is also desirable that the ratio of reducing agent to redox dye be at least about 2 to 1, more desirably at least about 5 to 1 and still more desirably at least about 10 to 1.
[0031] In another aspect of the invention, the primary redox reaction begun with contact with air may then initiate a secondary reaction that results in a color change. An example of this aspect is shown in Example 2. The primary reaction between a reducing agent and the air may, for example, result in a change in pH of the solution. The change in pH may then cause a color change through the use of pH sensitive dyes like those described in, for example The Sigma - Aldrich Handbook of Stains, Dyes and Indicators by the Aldrich Chemical Company (1990), ISBN 0-941633-22-5, at the inside back cover. Catalysts and buffers may also be used to control the reaction kinetics. The components of this aspect of the invention are discussed immediately below.
[0032] PH Sensitive Dyes
[0033] Suitable dyes may be activated between about the pHs of 4 and 9 or more particularly 5 and 8 for normal use on the human body and may thus be paired with the primary redox reactants in such a way as to produce the most effective color change. Suitable pH sensitive dyes include but are not limited to carminic acid, bromocresol green, chrysoidin, methyl red/Na salt, alizarin red S, cochineal, chlorphenol red, bromocresol purple, 4-nitrophenol, alizarin, nitrazine yellow, bromothymol blue, brilliant yellow, neutral red, rosolic acid, phenol red, 3-nitrophenol, orange II and so forth.
[0034] The amount of dye used in the practice of the invention should be between about 0.001 and 0.5 weight percent, more desirably between about 0.002 and 0.25 weight percent dye and still more desirably between about 0.003 and 0.1 weight percent.
[0035] Catalysts
[0036] The use of a catalyst, as the term is commonly understood in the scientific community, increases the ability of the designer to control the speed of the reaction by selecting the type and amount of catalyst present. An example of a catalyst is an enzyme, e.g.; glucose oxidase. The catalyst produces a change in the pH of the solution upon reaction with air (oxygen), which subsequently produces a color change through the use of a pH sensitive dye. An example of the effect of catalysts on the reaction is shown in Example 2. If a catalyst is used it may be present in an amount between about 0.001 and 0.5 weight percent.
[0037] pH Buffering
[0038] pH buffering is commonly used in chemical reactions to control the rate of reaction. In the case of the invention, a pH buffer may be used for this purpose as well as to increase the stability of the mixture in storage and transportation. The buffering capacity may be designed to be sufficient for any pH change induced by the relatively small amount of oxygen contained within the solution or in the “headspace” above the solution in the storage container, yet below that needed for buffering of the solution when exposed to large amounts of oxygen as occurs during use. Suitable pH buffers include but are not limited to sodium laureth sulfate and citric acid, and so forth. Selection of one or more buffering agents, however, would be dependent upon the reactants used, the choice of dye and the catalyst used, if any, and are within the ability of those skilled in the art to select.
[0039] In yet another aspect of the invention, the color change caused by both the redox dye and the pH sensitive dye compositions may be used together in the same solution. More than one reducing agent may also be employed to initiate the color change-producing redox reaction with the oxygen in the air.
[0040] The amount of time between dispensing and color change will depend on the formulation used as well as the energy used to introduce oxygen to the solution. Dispensing a color change soap solution onto the hands, followed by vigorous hand rubbing, for example, will result in a more rapid color change than would less vigorous hand rubbing. Reducing the amounts of dye and other components will likewise result in lengthening the time to the color change. Relatively simple experimentation with the amounts and types of soap, dye and other components discussed herein allows one to design a color change composition that will change color in a length of time up to about 5 minutes.
[0041] It is believed that the reversible color change feature of the invention would provide a fun and play aspect to a single chamber liquid soap. Each change of color from its starting color to a second color and back to the starting color is a “cycle” and it should also be noted that the color change cycle is dependent on the dye concentration. In the laboratory experiments discussed herein, the number of color change cycles possible ranged from 12 cycles to 35 cycles, depending on the dye concentration.
[0042] Dispensers
[0043] The indicator composition of the invention may be dispensed with, for example, liquid soap, in a number of different ways. One particular example is by the use of the liquid pump type dispenser, as illustrated in FIG. 1 . This dispenser contains soap 8 , has a lower intake member 10 , a central pump assembly 12 and an outlet member 14 . The lower intake member 10 extends downward into a supply container 16 for liquid soap 8 storage to a point near the bottom 18 . The lower intake member 10 within the supply container 16 is shown in dashed lines. The central pump assembly 12 has a check-valve and spring arrangement (not shown) which allows the one-way movement of liquid soap 8 through the pump assembly 12 . When a user pushes down on the upper outlet member 14 , the pump assembly 12 is actuated, moving liquid soap 8 upwardly from the supply container 16 , through the intake member 10 and pump assembly 12 and discharging it from the outlet member 14 .
[0044] It is believed that any of numerous dispensing mechanisms can be used with the present invention. As a further example is a foaming pump dispenser, such as, for example, described in U.S. Pat. No. 6,446,840. In reference to FIG. 2 , a foaming dispenser has a lower intake member 20 , a central pump assembly 22 , and an upper outlet member 24 . The intake member 20 has an open intake tube 26 extending into the liquid soap during normal operation, and connected to a lower extension 28 forming a liquid chamber 30 projecting from a housing 32 . A check-valve 34 permits flow only up into the chamber 30 from the tube 26 . The central pump assembly 22 has a foam-generating nozzle which, when pressurized with a liquid on one sides emits on the opposite side a swirling aerosol spray. Axial passages and radial ports allow air flow from the chamber 36 into the chamber 38 . The foaming chamber 38 holds a foam generator. The housing 32 is designed to sit on the rim of a supply container holding a body of liquid foamable soap or detergent.
[0045] Still another dispenser is seen in FIG. 3 . In this dispenser, the supply container 40 is pliable and is fitted with a valve 42 . Withdrawal of liquid soap 8 is accomplished by opening the valve 42 , inventing the dispenser, and squeezing the supply container 40 to force soap through the valve 42 and onto, for example, the hands.
[0046] Still another dispenser is shown in FIG. 4 and in which the supply container 50 is non-pliable. The supply container 50 is fitted with a removable top 52 which may be unscrewed from the supply container 50 so that liquid soap 8 may be removed manually by a user.
[0047] Yet another example of a dispenser is commonly used in wall mounting installations. This dispenser is depicted in FIG. 5 and described in U.S. Pat. No. 6,533,145 and U.S. Design Pat. No. 388,990, the contents of which are hereby incorporated by reference as if set forth in their entirety, and has a supply container 60 , a central pump assembly 62 and an outlet part 64 . Similarly to the pump dispenser of FIG. 1 , the central pump assembly 62 has a check-valve and spring arrangement (not shown) which allows the one-way movement of liquid soap through the pump assembly 62 . When a user pushes on the outlet part 64 , the pump assembly 62 is actuated, moving liquid the supply container 60 , through the pump assembly 62 and discharging it from the outlet part 64 . In various aspects of the inventions, the outlet part 64 may be located below the supply container 60 and the pump assembly 62 may be recessed within the supply container 60 .
[0048] Base Materials
[0049] The color change composition of the invention is suitable for addition to base materials such as toiletries. Toiletries include but are not limited to soaps (liquid and bar), skin lotions, colognes, sunscreens, shampoos, gels, toothpastes, mouthwashes and the like.
[0050] Base materials further include but are not limited to cleaning products such as hard surface cleansers and medical disinfectants. Hard surface cleansers incorporating the color change chemistry of the invention may be used in the home or business environment in, for example, food preparation areas. In such uses, the time from application to color change may be adjusted to provide effective microbial elimination. Likewise, medical disinfectants using the color change indicator of this invention can let a user know when a time sufficient for effective microbial control has elapsed.
[0051] Many toiletries and cleaners contain similar core ingredients; such as water and surfactants. They may also contain oils, detergents, emulsifiers, film formers, waxes, perfumes, preservatives, emollients, solvents, thickeners, humectants, chelating agents, stabilizers, pH adjusters, and so forth. In U.S. Pat. No. 3,658,985, for example, an anionic based composition contains a minor amount of a fatty acid alkanolamide. U.S. Pat. No. 3,769,398 discloses a betaine-based composition containing minor amounts of nonionic surfactants. U.S. Pat. No. 4,329,335 also discloses a composition containing a betaine surfactant as the major ingredient and minor amounts of a nonionic surfactant and of a fatty acid mono- or di-ethanolamide. U.S. Pat. No. 4,259,204 discloses a composition comprising 0.8 to 20% by weight of an anionic phosphoric acid ester and one additional surfactant which may be either anionic, amphitricha, or nonionic. U.S. Pat. No. 4,329,334 discloses an anionic amphoteric based composition containing a major amount of anionic surfactant and lesser amounts of a betaine and nonionic surfactants.
[0052] U.S. Pat. No. 3,935,129 discloses a liquid cleaning composition containing an alkali metal silicate, urea, glycerin, triethanolamine, an anionic detergent and a nonionic detergent. The silicate content determines the amount of anionic and/or nonionic detergent in the liquid cleaning composition. U.S. Pat. No. 4,129,515 discloses a liquid detergent comprising a mixture of substantially equal amounts of anionic and nonionic surfactants, alkanolamines and magnesium salts, and, optionally, zwitterionic surfactants as suds modifiers. U.S. Pat. No. 4,224,195 discloses an aqueous detergent composition comprising a specific group of nonionic detergents, namely, an ethylene oxide of a secondary alcohol, a specific group of anionic detergents, namely, a sulfuric ester salt of an ethylene oxide adduct of a secondary alcohol, and an amphoteric surfactant which may be a betaine, wherein either the anionic or nonionic surfactant may be the major ingredient. Detergent compositions containing all nonionic surfactants are shown in U.S. Pat. Nos. 4,154,706 and 4,329,336. U.S. Pat. No. 4,013,787 discloses a piperazine based polymer in conditioning and shampoo compositions. U.S. Pat. No. 4,450,091 discloses high viscosity compositions containing a blend of an amphoteric betaine surfactant, a polyoxybutylenepolyoxyethylene nonionic detergent, an anionic surfactant, a fatty acid alkanolamide and a polyoxyalkylene glycol fatty ester. U.S. Pat. No. 4,595,526 describes a composition comprising a nonionic surfactant, a betaine surfactant, an anionic surfactant and a C12-C14 fatty acid mono-ethanolamide foam stabilizer. The contents of the patents discussed herein are hereby incorporated by reference as if set forth in their entirety.
[0053] Further information on these ingredients may be obtained, for example, by reference to: Cosmetics & Toiletries , Vol. 102, No.3, Mar. 1987; Balsam, M. S., et al., editors, Cosmetics Science and Technology, 2nd edition, Vol. 1, pp 27-104 and 179-222 Wiley-Interscience, New York, 1972, Vol. 104, pp 67-111, Feb. 1989; Cosmetics & Toiletries , Vol. 103, No. 12 , pp 100-129, Dec. 1988, Nikitakis, J. M., editor, CTFA Cosmetic Ingredient Handbook , first edition, published by The Cosmetic, Toiletry and Fragrance Association, Inc., Washing-ton, D.C., 1988, Mukhtar, H, editor, Pharmacology of the Skin , CRC Press 1992; and Green, F J, The Sigma - Aldrich Handbook of Stains. Dyes and Indicators ; Aldrich Chemical Company, Milwaukee Wis., 1991, the contents of which are hereby incorporated by reference as if set forth in their entirety.
[0054] Exemplary materials that may be used in the practice of this invention further include but are not limited to those discussed in Cosmetic and Toiletry Formulations by Ernest W. Flick, ISBN 0-8155-1218-X, second edition, section XII (pages 707-744).
[0055] These include but are not limited to for example, the following formulations:
wt % Liquid hand soap EMERY 5310 coconut sulfosuccinate 20 EMERSAL 6400 sodium lauryl sulfate 10 EMID 6513 lauramide DEA 3 EMID 6540 linoleamide DEA 2 ETHOXYOL 1707 emulsifying acetate ester 1 EMERSOL 233 oleic acid 1 EMERESSENCE 1160 rose ether phenoxyethanol 1 Triethanolamine 0.5 Deionized water balance Liquid soap Ammonium laureth sulfate, 60% 24 Cocamidopropyl betaine 6 Stearamidopropyl dimethylamine 1.5 Sodium chloride 1.3 Glycol distearate 1 Citric acid 0.25 Methylparaben 0.15 Propylparaben 0.05 Bronopol 0.05 Water balance Bar soap Soap base 80/20 95.68 Water 1 Antioxidant 0.07 Perfume oil 0.75 Titanium dioxide 0.5 GLUCAM E-20 2
EXAMPLES
Example 1A
Redox Dye/Reducing Agent Producing Color Change
[0056] The formulation used was: 200 grams of Kimberly-Clark Professional antibacterial Clear Skin Cleanser (PCSC C2001-1824), 0.01 gram of Food Blue No.2 dye and 1.2 grams of glucose sugar. In weight percentage this was 0.005 weight percent dye and 0.6 weight percent sugar and the balance soap. The mixture was stirred at ambient temperature for 20 minutes to dissolve additives and then poured into a dispenser container. On standing, the color turned a pale yellow color.
[0057] In this example, Indigo Carmine (Food Blue No.2, FD&C No. 1) dye, normally blue/green in color, when mixed into a glucose/liquid soap solution, was reduced by the glucose to a pale yellow color. On exposure of the soap mixture to the air and with rubbing on the hands, oxygen oxidized the dye back to the green/blue color in about 10 to 20 seconds. Interestingly, there is not enough oxygen in the soap while sealed in a container to oxidize the reduced dye, thereby allowing it to remain yellow in the container.
[0058] As a variation of this Example 1A, a number of additional Examples 1B-1G were conducted with the same ingredients in different proportions and the time to initial color change noted. These examples used a soap solution of 500 ml of Kimberly-Clark Professional antibacterial Clear Skin Cleanser with 9 grams of glucose and a dye solution of 0.2 grams of Food Blue No. 2 in 100 ml of water. Samples were prepared by placing the dye solution in the amounts below into 100 ml beakers and adding the soap solution to make a total volume of 20 ml. Example 1G used 10 ml of the soap and glucose solution with another 9 ml of only soap, with 1 ml of dye solution.
Dye Stock Glucose Stock Solution (ml) Solution (ml) (gram of glucose) (mg of dye) time Example 17 (0.170 g) 3 (6 mg) <5 sec 1B 18 (0.180 g) 2 (4 mg) 5-10 sec 1C 19 (0.190 g) 1 (2 mg) 15-20 sec 1D 19.5 (0.195 g) 0.5 (1 mg) 40-50 sec 1E 19.75 (0.198 g) 0.25 (0.5 mg) 2 min +/− 1F 10 sec 10 plus 9 ml soap (0.10 g) 1 (2 mg) 15-20 sec 1G
[0059] Tailoring the time for initial color change can be seen therefore to be a relatively straight forward matter within the range of normal experimentation.
Example 2
pH Change Producing Color Change
[0060] The formulation used was: 76 grams of Kimberly-Clark Professional antibacterial Clear Skin Cleanser (PCSC C2001-1824), 1 gram of glucose oxidase enzyme catalyst and a trace amount of chlorophenol red (the initial mixture), followed by the addition of 6.4 milligrams of glucose sugar to 4.7 grams of the initial mixture. The initial mixture remained red upon mixing and after the addition of the glucose (the final mixture). The final mixture was placed on a tile and spread manually, resulting in a gradual color change to yellow in about 20 seconds.
[0061] This example of pH change producing a color change is the addition of a glucose enzyme catalyst and chlorophenol red to a soap solution. After mixing, glucose, having a redox potential of −0.42v, was added and the color (red) did not change. Upon agitation in air on a surface, however, sufficient oxygen was introduced to react the glucose, in the presence of the catalyst, to gluconic acid and so reduce the pH of the solution below 6, inducing a color change caused by the chlorophenol red.
Example 3
Redox Dye/Reducing Agent Producing Color Change Using Cysteine/Ascorbic Acid
[0062] Reagent stock solutions were made having the following compositions:
[0063] 2.0 grams of Indigo Carmine (Food Blue 1, FD&C Blue 2) redox dye dissolved in 1000 ml of tap water. Indigc Carmine dye is available from the Aldrich Chemical Company of Milwaukee Wis., catalog number 13,116-4.
[0064] 10 weight percent L-ascorbic acid reducing agent in tap water. Ascorbic acid is available from the Aldrich Chemical Company, catalog number 25,556-4.
[0065] 10 weight percent DL-cysteine reducing agent in tap water. Cysteine is available from the Aldrich Chemical Company, catalog number 86,167-7.
[0066] A series of water solutions were made with 1 ml of Indigo Carmine dye reagent stock solution and made up to 100 ml with tap water. Various amounts of the other two reagent stock solutions were added to this dye solution as shown below. After being shaken to initiate the color change, the compositions were then allowed to equilibrate and were timed for the reverse color change (to colorless) and tested for pH as indicated.
REAGENT Volume (ml) of Reagent Stock Solution Added Cysteine 0 0 0 0 1 5 10 20 1 5 10 20 Ascorbic 1 5 10 20 0 0 0 0 1 5 10 20 Acid Time To NC NC NC NC 90 130 260 ? 260 45 25 10 Colorless (min) pH 6.4 6.4 6.1 6.0 6.4 6.2 6.1 5.9 6.4 6.3 6.2 6.0 NC = No change in color after 19 hours. ? = Turned colorless sometime after 3 hours and before 19 hours.
[0067] The cysteine/ascorbic acid solution was tested in liquid soap formulations (PCSC C2001-1824) as well. The water solutions of the reagent stock solutions were added directly to 50 mls of liquid soap in the amounts indicated below. The compositions were again shaken and then allowed to equilibrate and the time to reverse the change color and the pH tested as reported.
Volume (ml) of Reagent SAMPLE Stock Solution Added Dye 1 3 1 1 3 Ascorbic Acid 0 0 9 20 20 Cysteine 0 0 9 20 20 Time to colorless NC NC 120 60 90 (min) pH 6.7 6.7 6.1 6.0 6.0
[0068] The blue to colorless change is reversible by shaking the liquid to introduce oxygen, which oxidizes the dye back to the blue color in about 20 seconds.
[0069] As can be seen from these results, the cysteine/ascorbic acid system can be used to formulate a color changing liquid soap with Indigo Carmine dye. Cysteine alone also causes a reversible de-colorization reaction to occur, but the reaction rate is much slower. In addition, substitutes known to those skilled in the art may be used for these reagents. Cysteine, for example, may substituted with glutathione, though the color change is somewhat slower. Indigo carmine dye may be substituted with 1, 9 dimethyl methylene blue (thiazine dye class) and brilliant cresyl blue acid (thazine dye class).
Example 4
Redox Dye/Reducing Agent Producing Color Change
[0070] The formulation used was: 200 grams of Kimberly-Clark Professional Moisturizing Instant Hand Antiseptic as given above, 0.01 gram of Food Blue No.2 dye and 1.2 grams of glucose sugar. On handwashing, the color turned from colorless to blue in about 10 to 20 seconds.
Example 5
Redox Dye/Reducing Agent Producing Color Change
[0071] The formulation used was: 200 grams of Kimberly-Clark Professional Eurobath Foaming Soap (P8273-PS117-81.102), 0.01 gram of Food Blue No.2 dye and 1.2 grams of glucose sugar. After mixing the ingredients, the white foam was place on the hand and with handwashing action the soap changed from white to blue. The foaming dispenser, as discussed above, also introduced enough oxygen to the soap upon dispensing that the soap changes color even without agitation in approximately 10 to 20 seconds.
Example 6
Redox Dyes Producing Color Change
[0072] The dyes were evaluated by preparing the formulation in Example 1A using the corresponding dye, washing the hands with running water, and grading the color and time to change. The following results were obtained.
Food Dye Color in Soap Color on Use Evaluation Blue 1 Yellow Blue Works Blue 2 Yellow Blue Works Red 40 Yellow Yellow Fails Green 3 Yellow Green Works Yellow 5 Yellow Yellow Fails
The study showed that Food Blue 1, 2 and Food Green 3 all work well in the liquid soap formulation.
Example 7
Evaluation Of Simple Sugars
[0074] A side-by-side study was carried out to examine the effect of substituting various simple sugars on the time taken for the color to revert back to the pale yellow. (Food blue No.2 was used as the dye.) It should be noted that the reaction of oxygen from the air to convert the colorless (or pale yellow) soap into a colored liquid during handwashing is very rapid. Thus, to study the reducing power of the various sugars the soap/dye solutions were shaken and the time taken to revert to colorless/pale yellow determined. The results are shown below:
Sugar Time (Seconds) Glucose 100 Xylose 80 Galactose 120 Sucrose No change
[0075] As will be appreciated by those skilled in the art, changes and variations to the invention are considered to be within the ability of those skilled in the art. Examples of such changes are contained in the patents identified above, each of which is incorporated herein by reference in its entirety to the extent it is consistent with this specification. Such changes and variations are intended by the inventors to be within the scope of the invention. | There is provided a color change composition that remains stable in a single phase and that contains an indicator that produces an observable color change after a period of time to show that sufficient cleaning has been done or to indicate the thoroughness of the cleaning. This use indicating color change is useful for, for example, in soap for teaching children to wash their hands for a sufficient period of time. This composition may be added to many different base materials to indicate time of use or as a way to introduce enjoyment to the activity. | 2 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of co-pending U.S. patent application Ser. No. 09/398,317, filed Sep. 16, 1999, which is herein incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to an apparatus and method for transferring objects in a processing system. More specifically, the present invention relates to a robot assembly having a multiple sided robot blade which can support one or more substrates.
[0004] 2. Background of the Related Art
[0005] Modern semiconductor processing systems typically process a large number of substrates by moving the substrates between a series of process chambers or enclosures using a robot. To increase the throughput rates of substrates, the trend is to increase the speeds at which substrates are moved in the system. However, increased speeds add complexity to the substrate handling systems. Increased speeds have decreased the allowable tolerances necessary to maintain repeatability because precise movement is needed to avoid damaging the substrate or the films formed thereon as the substrate is moved between the process chambers or enclosures using the robot.
[0006] One type of system used in substrate processing is a chemical mechanical polishing (CMP) system used to polish a substrate surface to remove high topography, surface defects, scratches, or embedded particles. FIG. 1 is a schematic perspective view of one CMP system known as a Mirra® CMP system available from Applied Materials, Inc. of Santa Clara, Calif., which is shown and described in U.S. Pat. No. 5,738,574, incorporated herein by reference. The system 2 includes a loading station 4 and three polishing stations 6 having polishing and/or rinsing pads 8 disposed therein. A rotatable multi-head carousel 10 having four polishing heads 12 is mounted above the stations and indexes the heads from station to station. The loading station 4 is supplied by a front-end substrate transfer region 14 disposed adjacent to the CMP system and is considered a part of the CMP system, although the transfer region 14 may be a separate component. The loading station 4 includes a pedestal 16 on which a substrate is supported following delivery by an overhead track robot 18 prior to and after processing in the polishing stations 6 . Vertically aligned substrate(s) 20 are held in cassette(s) 22 disposed in a fluid in a load tank 24 .
[0007] Generally, an overhead track robot 18 includes a downwardly extending blade support arm 28 , also known as a shoulder. A blade 26 is attached to the blade support arm at a pivot joint 30 , typically referred to as a wrist. The track robot 18 is capable of operating the blade support arm in three directions: in a linear direction along an X-axis across the front of the system, in a vertical direction along a Z-axis, and in a rotational direction about the Z-axis. Additionally, the blade 26 is capable of rotating about pivot joint 30 between a substantially horizontal position and a substantially vertical position. The blade 26 typically includes a vacuum port (not shown) for holding a substrate 20 to the blade during transfer within the system 2 .
[0008] [0008]FIG. 2 is a cross sectional schematic view of the overhead track robot 18 , showing details of the robot components. A blade support arm 28 is vertically disposed below a carriage 32 . The carriage 32 is attached to a drive belt 34 which is supported between two sheaves 36 , 38 . A motor 40 having a worm gear 42 is mounted on the carriage 32 and engages a mating gear 44 mounted on the support arm 28 . The blade support arm 28 supports a support column 60 that is connected to the pivot joint 30 . The pivot joint 30 includes a first portion 46 connected to the blade support arm 28 , a second portion 48 connected to a blade 26 , and a pivot element 50 pivotally connecting the first portion 46 with the second portion 48 of the pivot joint 30 . The pivot joint 30 allows the blade 26 to rotate at a pivot axis 52 between a horizontal and a vertical position. The blade 26 is a single-sided blade, i.e., the blade has one substrate supporting surface that is used to support the substrate during retrieval and delivery of a substrate 20 from and to the various stations. The carriage 32 houses a motor 54 having a worm gear 56 which passes through a worm nut 58 attached to the support column 60 . The blade support arm 28 houses a motor 62 which is attached to a drive shaft 64 and a worm gear 66 . The worm gear 66 engages a mating gear 68 on the pivot joint 30 . The blade 26 is attached by screws (not shown) to the pivot joint 30 .
[0009] The blade support arm 28 rotates about the Z-axis 70 when the motor 40 rotates the worm gear 42 which in turn rotates the mating gear 44 connected to the blade support arm. In the typical system, the pivot axis 52 is offset from the Z-axis 70 to enable use of a shorter blade 26 and consequently reduce blade deflection when extended horizontally in the system 2 on delivery and retrieval of a substrate 20 . The worm nut 58 rises and lowers on the worm gear 56 as the motor 54 rotates the worm gear 56 , thus raising and lowering the support column 60 attached thereto. To rotate the pivot joint 30 about the pivot axis 52 , the motor 62 rotates the drive shaft 64 which causes the worm gear 66 to rotate. Rotation of the worm gear 66 causes the mating gear 68 to rotate, thus rotating the second portion 48 of the pivot joint 30 and the blade 26 attached thereto.
[0010] Typically, in loading the substrate 20 into the system 2 , the robot 18 rotates the blade 26 into a vertical position, aligns the blade 26 with the substrate, lowers the blade 26 into an adjacent position with the substrate 20 , and vacuum chucks a substrate 20 on a substrate supporting surface of the blade 26 . A vacuum provided to a port on the blade supplies a vacuum to hold the substrate 20 to the supporting surface of the blade 26 so that when the blade is raised vertically, the substrate remains supported by the blade in the vertical position. The robot 18 then rotates the blade 26 about the pivot joint 30 into a substantially horizontal position, moves in the X-direction toward the loading station 4 rotates the blade about the Z-axis 70 , aligns the blade with a loading station 4 , and delivers the substrate to the loading station. The loading station pedestal 16 raises to engage the substrate 20 and lowers the substrate below the blade 26 so that the blade 26 can retract out of the loading station 4 . One of the heads 12 indexes above the pedestal 16 , the pedestal 16 raises the substrate 20 into contact with the head, the head chucks the substrate and indexes to a polishing station 6 for processing. After processing at the station(s), the substrate 20 is returned to the loading station 4 . The robot 18 aligns the robot blade 26 with the loading station 4 to retrieve the processed substrate, retrieves the processed substrate, traverses the X-axis back into an unloading position at the load tank 24 , and returns the substrate 20 to the load tank 24 . The robot then loads another unprocessed substrate and delivers the substrate to the loading station 4 .
[0011] One problem with this conventional design and process is that the system may sit idle while awaiting retrieval of an unprocessed substrate following removal of a processed substrate. The time required for the robot to cycle between a processed substrate and an unprocessed substrate is typically referred to as the “swap” time. In the system referenced in FIG. 1, the swap time includes the time required to retrieve and place a processed substrate in the load tank and retrieve and deliver an unprocessed substrate to the loading station.
[0012] There remains a need for a system and method that can reduce the swap time required to pick up a processed substrate and position an unprocessed substrate for processing in the system.
SUMMARY OF THE INVENTION
[0013] The present invention generally provides a processing system having a robot assembly which includes a multiple sided robot blade that can support a substrate on at least two sides thereof and associated methods to transfer one or more substrates in a processing system. An unprocessed substrate can be supported on the blade while a processed substrate is retrieved from a location to which the unprocessed substrate is to be delivered. The processing throughput rate is increased by reducing the movements required by the robot to exchange processed substrates and unprocessed substrates, thus decreasing the swap time.
[0014] In one aspect, the invention provides a substrate processing system, comprising an enclosure, a robot as least partially disposed within the enclosure, and a multiple sided robot blade attached to the robot and adapted to support substrates on at least two surfaces thereof. The robot can include a blade support arm connected to a drive mechanism, a pivot joint connected to the blade support arm, a two sided blade connected to the pivot joint, and associated actuators and controllers. In another aspect, the invention provides a robot blade for a substrate processing system, comprising a first and a second substrate supporting surface on opposed faces of the blade.
[0015] In another aspect, the invention provides a method for transferring substrates in a processing system, comprising supporting a first substrate on a first substrate supporting surface of a robot blade, retrieving a second substrate on a second substrate supporting surface of the robot blade from the system, and delivering the first substrate supported on the first substrate supporting surface to the system while supporting the second substrate on the second substrate supporting surface. In another aspect, the invention provides a method of transferring substrates in a processing system using a robot, comprising retrieving a first substrate from a first location and supporting the first substrate on a first substrate supporting surface of a robot blade, positioning the robot blade to retrieve a second substrate from a second location, retrieving the second substrate from the second location and supporting the second substrate on a second substrate supporting surface of the blade, delivering the first substrate to the second location, and delivering the second substrate to another location in the system.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] So that the manner in which the above recited features, advantages and objects of the present invention are attained and can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to the embodiments thereof which are illustrated in the appended drawings.
[0017] It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.
[0018] [0018]FIG. 1 is a schematic perspective view of a typical processing system.
[0019] [0019]FIG. 2 is a schematic cross sectional view of a typical track robot having a blade support arm and a robot blade.
[0020] [0020]FIG. 3 is a schematic cross sectional view of one embodiment of the robot of the present invention.
[0021] [0021]FIG. 4 a is a schematic top view of one embodiment of the robot blade.
[0022] [0022]FIG. 4 b is a schematic bottom view of the robot blade of FIG. 4 a.
[0023] [0023]FIG. 4 c is a schematic cross sectional view of FIG. 4 a through the blade showing the longitudinal channels.
[0024] [0024]FIG. 4 d is a schematic cross sectional view of FIG. 4 a through the blade showing the transverse channels.
[0025] [0025]FIG. 4 e is a schematic side view of the robot blade of FIG. 4 a.
[0026] [0026]FIG. 5 is a schematic cross sectional view of another embodiment of the robot of the present invention.
[0027] [0027]FIG. 6 is a schematic side view of the robot with the blade in a vertical position with a first substrate over a first location.
[0028] [0028]FIG. 7 is a schematic side view of the robot with the blade rotated to a substantially horizontal position with a first substrate.
[0029] [0029]FIG. 8 is a schematic side view of the robot with the blade supporting the first and second substrates on the first and second substrate supporting surfaces, respectively.
[0030] [0030]FIG. 9 is a schematic side view of the robot with the blade rotated about a pivot joint from the position referenced in FIG. 8.
[0031] [0031]FIG. 10 is a schematic side view of the robot with the blade rotated about a first axis.
[0032] [0032]FIG. 11 is a schematic side view of the robot with the blade having unloaded the first substrate into a second location while supporting the second substrate.
[0033] [0033]FIG. 12 is a schematic side view of the robot with the blade in a vertical position with a second substrate over the first location.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0034] The present invention generally provides a processing system having a robot assembly with a multiple sided robot blade that can support a plurality of substrates on at least two sides thereof. In general, the system includes an enclosure, such as a CMP system 2 , and a robot, such as an overhead track robot 72 shown in FIG. 3. The system may also include a loading station 4 adjacent a plurality of polishing stations 6 . The loading station 4 is supplied with substrates by an overhead track robot 72 disposed in a substrate transfer region 14 above a load tank 24 having a plurality of cassette(s) 22 .
[0035] [0035]FIG. 3 is a schematic cross sectional view of one embodiment of the robot 72 of the system. A carriage 74 is attached to the drive belt 76 which is supported between two sheaves 78 , 80 . A blade support arm 82 is connected to the carriage 74 and is vertically disposed below the carriage 74 . The blade support arm 82 supports a support column 84 that is connected to a pivot joint 86 . The pivot joint 86 includes a first portion 88 connected to the blade support arm 82 , a second portion 90 connected to a multiple-sided robot blade 94 , and a pivot element 92 pivotally connecting the first portion 88 with the second portion 90 of the pivot joint 86 . The robot blade 94 includes at least two substrate supporting surfaces 96 , 98 to support one or more substrates. Preferably, the blade support arm 82 can rotate at least 180° around a first axis 100 to assist the blade in moving from a first location to a second location. The pivot joint 86 having a pivot axis 102 allows the blade 94 to rotate at least 180° from a first horizontal position 104 as shown through a vertical position 106 to at least a second horizontal position 108 . The carriage 74 houses a motor 110 having a worm drive 112 which passes through a worm nut 114 attached to the support column 84 . The carriage 74 is connected to a motor 116 having a worm gear 118 . The worm gear 118 is engaged with a mating gear 120 that is connected to the blade support arm 82 . The blade support arm 82 houses a motor 122 which is attached to a drive shaft 124 and a worm gear 126 . The worm gear 126 engages a mating gear 128 coupled to the second portion 90 of the pivot joint 86 .
[0036] The blade support arm 82 rotates about a first axis 100 when the motor 116 rotates the worm gear 118 which in turn rotates the mating gear 120 connected to the blade support arm 82 . The motor 110 rotates the worm gear 112 to raise and lower the support column 84 . The worm nut 114 rises and lowers on the worm gear 112 , thus raising and lowering the support column 84 attached thereto. To rotate the pivot joint 86 about the pivot axis 102 , the motor 122 rotates the drive shaft 124 which rotates the worm gear 126 . The worm gear 126 rotates the mating gear 128 that is coupled to the second portion 90 of the pivot joint 86 and the blade 94 connected thereto.
[0037] In the embodiment shown in FIG. 3, the vertical first axis 100 is substantially aligned in a transverse direction with the horizontal pivot axis 102 , so that the first axis substantially intersects the pivot axis. The intersection of axes allows the first substrate supporting surface 96 to be symmetrically aligned with the second substrate supporting surface 98 when the blade 94 is rotated about the first axis 100 and about the pivot axis 102 . For example, in the embodiment described in FIG. 3, the first substrate supporting surface 96 is disposed upwardly and the second substrate supporting surface 98 is disposed downwardly at position 104 . The blade 94 can be rotated at least 180° about the pivot axis 102 through a vertical position 106 to a second horizontal position 108 , where the first substrate supporting surface 96 is downwardly disposed and the second substrate supporting surface 98 is upwardly disposed. The blade 94 can also be rotated at least 180° about the first axis 100 , so that the blade 94 returns to position 104 , but this time the first substrate supporting surface 96 is downwardly disposed and the second substrate supporting surface 98 is upwardly disposed, in contrast to the original relative positions. Thus, the blade 94 can rotate about both axes 100 , 102 and preserve the symmetry between substrate positions of the first and the second substrate supporting surfaces 96 , 98 . The substantial intersection of the two axes 100 , 102 should be at least enough so that upon repositioning a second substrate to the position of a first substrate, enough symmetry is maintained to satisfy normal manufacturing and placement tolerances of the equipment for interchangeable placement of the substrates. In some embodiments, where the axes are not aligned, the robot 72 could compensate for the relative difference by, for instance, programming a controller 130 for positional relative movements.
[0038] The blade 94 will now be described in reference to FIGS. 4 a and 4 b . FIG. 4 a is a schematic top view of the blade 94 . FIG. 4 b is a schematic bottom view of the blade 94 , showing similar components as the top view of the blade. The blade 94 is an elongated thin member, preferably made of stainless steel, having a first substrate supporting surface 96 and a second substrate supporting surface 98 . The blade 94 can be made of other materials, such as alumina, silicon carbide, or other ceramics or combinations thereof. The blade 94 can have an intermediate section 132 between two end sections 134 , 136 that is narrower in width than the two end sections. The blade 94 is attached to the pivot joint 86 by screws (not shown) disposed through holes 138 . The first substrate supporting surface 96 defines a longitudinal channel 140 aligned along the length of the blade 94 and a transverse channel 142 , where the longitudinal channel 140 intersects the transverse channel 142 . Similarly, the second substrate supporting surface 98 defines a longitudinal channel 144 and a transverse channel 146 , where the longitudinal channel 144 intersects the transverse channel 146 . The longitudinal channel 140 and transverse channel 142 on the first substrate supporting surface 96 are isolated from the longitudinal channel 144 and transverse channel 146 on the second substrate supporting surface 98 . The channels 140 , 142 , 144 , 146 can be any shape and size as needed to support the particular substrate in the particular process. Each longitudinal channel 140 , 144 is sealably covered by covers 148 , 150 respectively, to allow the longitudinal channels to sealably communicate with the transverse channels. Gaskets 152 , 154 are affixed to the blade 94 in proximity to the transverse channels 142 , 146 to assist is sealing between the substrate and the respective substrate supporting surface when the substrate is supported by the substrate supporting surface through, for example, a vacuum applied to the channels.
[0039] The second portion 90 of the pivot joint 86 preferably has at least two independent ports 156 , 158 that are connected to one end of hoses 160 , 162 , respectively. The port 156 is coupled to a port 164 on the blade 94 which fluidicly communicates with the channel 140 . Similarly, port 158 is coupled to port 166 on the blade 94 which fluidicly communicates with the channel 144 . Another end of the hose 160 is directed past the pivot joint 86 and then upward along the blade support arm 82 to pressure sensor 168 and to valve 170 . Similarly, another end of the hose 162 is directed past the pivot joint 86 and then upward along the blade support arm 82 to pressure sensor 172 and to valve 174 . The valves 170 , 174 can be mounted on the robot 72 and controlled by controller 130 . The valves 170 , 174 are preferably three-way valves having three ports. On valve 170 , a first port 176 is connected to a pressure source 178 , the second port 180 is connected to a vacuum source 182 , and the third port 184 is fluidicly connected to the sensor 168 and the hose 160 . Similarly, on valve 174 , a first port 186 is connected to the pressure source 178 , the second port 188 is connected to the vacuum source 182 , and the third port 190 is fluidicly connected to the sensor 172 and the hose 162 .
[0040] The ports 164 , 166 allow the independent placement of at least two substrates. In other embodiments, a single port, or multiple ports coupled together, could be used so that when one substrate was released on one side, the other substrate on the other side would be released from the vacuum. For instance, in an upright position, a substrate on top of the blade 94 could rely on gravity to remain substantially stationary while a substrate underneath the blade was unloaded, such as a loading station, and then reapply the vacuum to the blade 94 to support the substrate remaining on the blade.
[0041] [0041]FIG. 4 c is a schematic cross sectional view through the blade, showing the longitudinal channels referenced in FIG. 4 a . Substrate supporting surface 96 includes the longitudinal channel 140 aligned longitudinally to the length of the blade. The longitudinal channel is preferably pneumatically sealed with a cover 148 . The cover 148 can be attached to the blade 94 preferably by welding, such as electron beam welding, or it can be fastened, adhesively attached or otherwise connected. Substrate supporting surface 98 is similarly arranged and the longitudinal channel 144 is preferably pneumatically sealed with a cover 150 . The port 164 is disposed through the cover 148 and fluidicly connected to the channel 140 . Likewise, port 166 is disposed through the blade 94 and fluidicly connected to the channel 144 .
[0042] The cross sectional area of the channels 140 , 144 is preferably about the same as the cross sectional area of the hoses 160 , 162 . Furthermore, the channels 140 , 144 preferably have a width (W) to height (H) ratio of less than about 38:1 and more preferably a W:H ratio of about 21:1 or less.
[0043] [0043]FIG. 4 d is a schematic cross sectional view through the blade, showing the transverse channels 142 , 146 referenced in FIG. 4 a . On the substrate supporting surface 96 , the longitudinal channel 140 is fluidicly connected to the transverse channel 142 . On substrate supporting surface 98 , the longitudinal channel 144 is fluidicly connected to the transverse channel 146 . A blade web 192 isolates the longitudinal channel 140 and transverse channel 142 from the longitudinal channel 144 and transverse channel 146 . The isolation of the channels allows independent control over each substrate (not shown) held to each substrate supporting surface 96 , 98 .
[0044] [0044]FIG. 4 e is a side view of the blade 94 attached to the pivot joint 86 . Hose 160 is coupled to port 156 and hose 162 is coupled to port 158 . The port 156 is coupled to port 164 on the blade 94 and the port 158 is coupled to the port 166 on the blade 94 , where each of the ports are upwardly disposed on the blade 94 . Gaskets 152 , 154 are disposed toward the end of the blade 94 .
[0045] Other methods of supporting substrates on the blade can be used, such as electrostatic chucks, adhesive substances such as polymers, and mechanical devices such as “grippers” and other clamps. Also, multiple ports or other methods of support could be used on one substrate supporting surface. For instance, if more than one substrate were supported on one substrate supporting surface, then each substrate could be supported and released independently on that substrate supporting surface.
[0046] A controller 130 , shown in FIGS. 3 and 4 a , controls the functions of the robot movement, rotation and linear actuators, power supplies, and other associated components and functions. In general, the controller 130 preferably comprises a programmable microprocessor and executes system control software stored in a memory, which in the preferred embodiment is a hard disk drive, and can include analog and digital input/output boards, interface boards, and stepper motor controller boards (not shown). The controller 130 controls electrical power to the components of the system and includes a panel that allows an operator to monitor and operate the system. Optical and/or magnetic sensors (not shown) are generally used to move and determine the position of movable mechanical assemblies. The controller 130 also controls a pressure and a vacuum system, such as pressure source 178 , vacuum source 182 , and valves 170 , 174 . A vacuum can be supplied through the hoses 160 , 162 to the blade 94 when the blade is lowered into the load tank 24 and allows the blade to retrieve and support the substrate 20 . The particular sensor, either sensor 168 or sensor 172 , coupled to the surface of the blade supporting the substrate 20 senses a change in vacuum performance with the substrate on the particular surface. The surface of the blade 94 not supporting a substrate 20 is exposed to the fluid in the load tank 24 and can entrain some fluid into the channel from that surface. The sensor for the respective surface with the entrained load tank fluid senses no8 substrate on that surface and switches the respective valve from the valve second port which allows vacuum to the respective port on the blade to the valve first port which allows pressurized fluid to the respective port on the blade. The pressurized fluid flows outward through the channel on the substrate supporting surface not supporting the substrate to purge the channel of the load tank fluid, thus creating a purge mode, while the port to the substrate supporting surface supporting the substrate maintains vacuum on the substrate. Preferably, the controller 130 defaults to a purge mode except when the particular surface(s) is supporting the substrate(s).
[0047] [0047]FIG. 5 is a schematic perspective view of another embodiment of the robot including the multiple sided blade 94 and associated components. In this embodiment, the robot blade is able to rotate about a blade axis 194 in addition to being able to rotate about the first axis 100 and the pivot axis 102 , described herein. The pivot joint 196 includes a first portion 198 connected to the blade support arm 82 , a second portion 200 connected to a rotatable actuator 202 , and a pivot element 204 pivotally connecting the first portion 198 with the second portion 200 of the pivot joint 196 . The rotatable actuator 202 is coupled to the blade 94 and can rotate the blade about the blade axis 194 . The actuator 202 , such as a servomotor, preferably directly drives the rotation of the blade 94 . The actuator 202 could have the typical pneumatic lines if pneumatic actuation is used. The controller 130 , referenced in FIG. 3, can also be used to control the actuator. A sensor 206 , such as an optical sensor, may be coupled to the actuator 202 to determine the position of the blade 94 and provide input to the controller 130 . The pivot joint 196 allows the blade 94 to rotate at the pivot axis 102 . The blade support arm 82 can also rotate about 180° around the first axis 100 .
[0048] The actuator 202 can rotate the blade 94 about the blade axis 194 to selectively position the first substrate supporting surface 96 and the second substrate supporting surface 98 in a face up or face down position. In the embodiment shown, the pivot joint 196 could be rotated about 90° from a substantially vertical position to a substantially horizontal position to retrieve and deliver the substrate 20 from the load tank 24 and the loading station 4 , referenced in FIG. 1. Because the actuator 202 can rotate the blade 94 with a first and second substrate supporting surfaces between face up and face down positions, the pivot axis 102 need not be aligned with the first axis 100 nor does the pivot joint 196 need to rotate about the pivot axis 102 through at least 180°.
[0049] FIGS. 6 - 12 show schematic side views of an operational sequence for transferring a first substrate 210 and second substrate 212 between a first location 214 and a second location 216 in a CMP system. FIG. 6 is a schematic side view of the robot 72 with the blade 94 in a vertical position over the load tank 24 . In operation, a controller 130 determines that the loading station 4 needs or will need a substrate, for instance, by using a sensor or timer (not shown) to determine that a substrate has been processed or will be processed. The controller 130 activates the robot 72 to rotate the blade 94 about the pivot joint 86 to a substantially vertical position to retrieve a first substrate 210 from the load tank 24 . The first substrate 210 is held on the blade 94 by, for example, a vacuum source. The blade support arm 82 raises the blade 94 and substrate supported thereon in a vertical direction to clear the load tank 24 . The blade 94 is then moved into a horizontal position.
[0050] [0050]FIG. 7 is a schematic side view of the robot 72 with the blade 94 supporting a first substrate 210 rotated to a substantially horizontal position. The blade 94 has been rotated about the pivot joint 86 by about 90° from the position referenced in FIG. 6. Also, the robot 72 has moved the blade support arm 82 and blade 94 to a position over a second substrate 212 disposed in the loading station 4 . The second substrate 212 is positioned adjacent the lower surface of the blade and chucked thereto. The robot 72 then retracts from the loading station as shown in FIG. 8.
[0051] [0051]FIG. 8 is a schematic side view of the robot 72 with the blade 94 supporting the first and second substrates on the first and second substrate supporting surfaces, respectively. In this embodiment, both substrate supporting surfaces of the blade 94 are used to support the substrates 210 , 212 by a vacuum, although other techniques of holding the substrates in place known in the art, such as mechanical grippers and adhesive films, can be used. In this view, the first substrate 210 is disposed in a top position on the blade 94 and the second substrate 212 is disposed in a bottom position on the blade 94 .
[0052] The blade 94 is then rotated 180 ° about the pivot joint 86 and its axis 102 as shown in FIG. 9. As a result of the rotation, the two substrates are “flipped” so that the first substrate 210 , which was at the top position 210 ′ of the blade 94 , is relocated to the bottom of the blade. Similarly, the second substrate 212 , which was at the bottom position 212 ′, is relocated to the top of the blade 94 . The blade 94 is then rotated 180° about a first axis 100 to position the blade for re-entry into the loading station 4 , as shown in FIG. 10.
[0053] The blade 94 then moves to the loading station 4 and the first substrate 210 is unloaded into the loading station 4 , as shown in FIG. 11. The second substrate 212 remains supported on the blade.
[0054] The blade 94 is then moved from a horizontal position to a vertical position to align the second substrate 212 over an open position in the load tank 24 as shown in FIG. 12. Alternatively, the second substrate 212 could be moved to an inspection device and another substrate retrieved from the inspection device and loaded into the loading tank 24 . A substrate purge sequence could be performed at the inspection station as well.
[0055] Variations in the orientation of the blade, substrates, robot, robot support arm, loading stations, and other system components are possible. Additionally, all movements and positions, such as “above”, “top”, “below”, “bottom”, “side”, described herein are relative to positions of objects such as the robot blade, the substrates, and the first and second locations. Accordingly, it is contemplated by the present invention to orient any or all of the components to achieve the desired movement of substrates through a processing system.
[0056] While foregoing is directed to the preferred embodiment of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow. | The present invention generally provides a processing system having a robot assembly which includes a multiple sided robot blade that can support a substrate on at least two sides thereof and associated methods to transfer one or more substrates in a processing system. An unprocessed substrate can be supported on the blade while a processed substrate is retrieved from a location to which the unprocessed substrate is to be delivered. The processing throughput rate is increased by reducing the movements required by the robot to exchange processed substrates and unprocessed substrates, thus decreasing the swap time. | 8 |
BACKGROUND OF THE INVENTION
The present invention relates to an organopolysiloxane composition curable by condensation reaction or, in particular, to an organopolysiloxane composition curable by condensation reaction with extended pot life.
The condensation reaction between organopolysiloxanes is a well known reaction and widely utilized in preparing various kinds of silicone products. The products by the condensation reaction are used as intermediate compounds for the preparation of various kinds of products with complicated structures or used per se as final objective products of value. For example, they are used as a mold release agent or a coating material on a release paper. When the intended use of these organopolysiloxane compositions is in the preparation of a release paper, they are put to use by adding a catalyst for accelerating the condensation reaction. The catalyst-added organopolysiloxane composition has desirably a sufficiently long pot life at room temperature. In other words, the velocity of the crosslink formation in the composition by the condensation reaction should be as low as possible at room temperature after admixing of the condensation catalyst. On the other hand, the curing velocity of the catalyst-added organopolysiloxane composition must be sufficiently large at an elevated temperature to give good productivity in the production process by use of the composition.
In recent years, there is known an organopolysiloxane composition curable by condensation reaction with improved curing velocity but such a type of the composition suffers from shortened pot life. The requirements for the pot life as long as possible and for the large curing velocity cannot be compatible with each other because an extended pot life is obtained only in the sacrifice of the curing velocity. This problem of undesirably short pot life is especially difficult to solve in an organopolysiloxane composition in which the condensation reaction takes place by the dehydrogenation reaction between silicon-bonded hydroxy groups and silicon-bonded hydrogen atoms among various types of the condensation reactions including dehydration condensation between silicon-bonded hydroxy groups, dealcoholation condensation between silicon-bonded hydroxy groups and silicon-bonded alkoxy groups and de(carboxylic acid) condensation between silicon-bonded hydroxy groups and silicon-bonded acyloxy groups and the like.
Therefore it has been a generally accepted practice that the extension of the pot life is achieved by the dilution of the organopolysiloxane composition having large curing velocity with large volume of an organic solvent. As a trend in recent years, however, the amount of an organic solvent to be added to such a composition is limited further and further from the standpoint of toxicity against human body, danger of fire or explosion and the problem of air pollution as well as from the standpoint of saving of natural resources. Thus it is eagerly desired to develop an organopolysiloxane composition having sufficiently extended pot life along with no influence on the curing velocity and on the properties of the composition after curing by use of a minimum volume of an organic solvent.
Besides the organopolysiloxane compositions curable by condensation reaction, on the other hand, there is known another type of organopolysiloxane compositions curable by addition reaction. For this type of organopolysiloxane compositions, several kinds of effective reaction retarders are proposed such as acetylenic compounds as a result of investigations and they are widely utilized industrially.
Unfortunately, no reaction retarders are known for the organopolysiloxane compositions curable by condensation reaction with exception of acetic acid and the like with only limited effects (see Japanese Patent Publication SHO 38-13913) necessitating to recur to the use of large volumes of organic solvents to dilute the composition. In addition, the method relying on acetic and the like is inapplicable to the organopolysiloxane compositions used in a high solid concentration or as solvent-free and it is also inapplicable to the organopolysiloxane compositions used in the form of an aqueous emulsion since such an additive is sometimes harmful to the stability of the aqueous emulsion.
In addition, the curable organopolysiloxane compositions of the above described type have a problem that, when used as a coating agent on release papers, the coating and heat-curing steps of the composition must follow as soon as possible the admixing of the curing catalyst into the composition because a delay in the coating and heat-curing sometimes leads to undesirable increase in the peeling resistance of the finished release paper products to such an extent as inapplicable to practical use.
In short, the conventional reaction retarders described above have very little effectiveness in retarding the condensation reaction and are hardly applicable to the organopolysiloxane compositions of high-solid type or aqueous emulsion type.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to present a reaction retarder applicable to various types of organopolysiloxane compositions curable by the mechanism of condensation reaction, in particular, by the mechanism of dehydrogenation very effective even in a small amount of addition without a danger of destroying aqueous emulsions and having no adverse effects on the curing velocity of the composition when put to use as well as on the properties of the cured composition such as the mechanical strengths of the films formed thereof and the releasability of the surface.
The present invention completed as a result of the inventors' extensive investigations relates to an organopolysiloxane composition formulated with the addition of a reaction retarder to satisfy the above requirements and the organopolysiloxane composition of the invention comprises
(a) 100 parts by weight of a diorganopolysiloxane terminated at both chain ends with hydroxy groups directly bonded to the silicon atoms,
(b) from 0.1 to 50 parts by weight of an organohydrogenpolysiloxane having, in a molecule, at least three hydrogen atoms directly bonded to the silicon atoms,
(c) from 1 to 20 parts by weight of a catalyst for condensation reaction,
(d) from 5 to 80% by weight, based on the amount of the component (c) above, of an acyloxysilane compound represented by the general formula
R.sub.3.sup.1 SiOCOR.sup.2 (I)
where R 1 and R 2 are each a monovalent hydrocarbon or halogenated hydrocarbon group having 1 to 18 carbon atoms, and
(e) from zero to 50% by weight, based on the amount of the component (c) above, of a carboxylic acid represented by the general formula
R.sup.3 COOH (II)
where R 3 is a monovalent hydrocarbon or halogenated hydrocarbon group having 1 to 6 carbon atoms.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The organopolysiloxane composition of the present invention is now described below in further detail.
The component (a) which is the main ingredient of the inventive composition is a substantially linear diorganopolysiloxane expressed by the general formula ##STR1## where R is a substituted or unsubstituted monovalent hydrocarbon group and P is a positive integer, terminated at both chain ends with hydroxy groups directly bonded to the silicon atoms. The group R is exemplified by alkyl groups such as methyl, ethyl and propyl groups; alkenyl groups such as vinyl and allyl groups; cycloalkyl groups; cycloalkenyl groups; aryl groups such as phenyl group; halogenated hydrocarbon groups; cyano-substituted hydrocarbon groups; cyano-substituted hydrocarbon groups; and the like. It is preferable that the diorganopolysiloxane as the component (a) has a viscosity of at least 10 centistokes at 25° C. in order that the cured product of the composition may have sufficiently high mechanical strengths.
Several of the examples of the diorganopolysiloxane suitable as the component (a) are shown by the following structural formulas, in which, and hereinafter, Me, Vi and Ph denote methyl, vinyl and phenyl groups, respectivly, and m and n are each a positive integer. ##STR2##
The second component (b) in the inventive composition serves as a crosslinking agent by the condensation reaction with the diorganopolysiloxane as the component (a) above and the organohydrogenpolysiloxane as the component (b) is expressed by the average unit formula ##EQU1## where R' has the same meaning as defined for R above and b and c are each a positive number with the proviso that 2≦b+c≦3. In order that the component (b) serves as a crosslinking agent, the organohydrogenpolysiloxane should have at least three hydrogen atoms directly bonded to the silicon atoms in a molecule. The molecular configuration of the organohydrogenpolysiloxane is not limitative including linear chains, branched chains and cyclic rings in so far as it has at least three silicon-bonded hydrogen atoms in a molecule and it is also not limited rheologically including oily fluids, gums and resins.
It is preferable that the organohydrogenpolysiloxane as the component (b) has a viscosity of at least 10 centistokes at 25° C. in order that the cured products of the composition may have sufficiently high mechanical strengths.
Typical examples of the organohydrogenpolysiloxane as the component (b) in the present invention are dimethylhydrogenpolysiloxanes having a linear molecular configuration of various degrees of polymerization terminated at both chain ends with trimethylsilyl groups or dimethylhydrogensilyl groups, copolymeric linear organohydrogenpolysiloxanes composed of diorganosiloxane units and monoorganohydrogen siloxane units and terminated with triorganosilyl groups or diorganohydrogensilyl groups at the chain ends with various degrees of polymerization and copolymeric branched-chain organohydrogenpolysiloxanes composed of the siloxane units of SiO 2 and R 2 HSiO 0 .5 units, where R is the same as defined above, including tetrakis(dimethylhydrogensiloxay)silane expressed by the structural formula Si(--OSiMe 2 H) 4 and those having complicated molecular structures.
The amount of the component (b) to be formulated in the inventive composition is in the range from 0.1 to 50 parts by weight or, preferably, from 0.5 to 20 parts by weight per 100 parts by weight of the component (a) since smaller amounts of the component (b) than above result in insufficient cure of the composition while excessive amounts of the component (b) over the above range give no particular advantages with only economical disadvantages.
The condensation catalyst as the component (c) in the inventive composition may be a conventional one with no specific limitation used in the prior art compositions of the similar type as exemplified by dibutyltin dilaurate, dibutyltin dioctoate, dibutyltin diacetate, zinc octoate, tetrabutyl titanate, iron stearate, lead octoate and the like.
The amount of the condensation catalyst as the component (c) is preferably in the range from 1 to 20 parts by weight per 100 parts by weight of the component (a) since smaller amounts than above result in insufficient curing of the inventive composition while excessive amounts over the above range give no particular advantages.
The components (d) and (e) serves to impart sufficient pot life to the inventive composition and the component (d) is an acyloxysilane represented by the general formula (I) above, in which R 1 and R 2 in the formula are each a monovalent hydrocarbon group or halogenated hydrocarbon group with 1-18 carbon atoms exemplified by alkyl groups such as methyl, ethyl, propyl, octyl, undecyl, heptadecyl and octadecyl groups; alkenyl groups such as vinyl and allyl groups; aryl groups such as phenyl groups; and those groups having one or more of halogen atoms, e.g. chlorine or fluorine atoms, in substitution of the hydrogen atoms in the above named hydrocarbon groups such as chloromethyl, trichloroethyl, perfluoropropyl, perfluorovinyl groups and the like.
Several of the examples of the acyloxysilanes suitable for use as the component (d) in the inventive composition are shown by the formulas given below, in which, and hereinafter, Pr denotes a propyl group. ##STR3##
These acyloxysilanes are readily prepared by the well known synthetic methods. For example, the method for the synthesis of trimethylacetoxysilane is described in Journal of the American Chemical Society, Vol. 69, page 2110 (1947).
In the above given general formula (II) representing the carboxylic acid as the component (e), R 3 is a monovalent hydrocarbon or halogenated hydrocarbon group having 1 to 6 carbon atoms as exemplified by alkyl groups such as methyl, ethyl, propyl, butyl and hexyl groups; cycloalkyl groups such as cyclohexyl group; alkenyl groups such as vinyl and allyl groups; aryl groups such as phenyl group, and those groups having one or more of halogen atoms, e.g. chlorine or fluorine atoms, in substitution of the hydrogen atoms in the above named hydrocarbon groups such as chloromethyl, trichloroethyl, perfluoropropyl and perfluorovinyl groups.
Several of the examples of the carboxylic acids as the component (e) in the inventive composition are acetic acid, propionic acid, n-butyric acid, benzoic acid, dichloroacetic acid, trichloroacetic acid, trifluoroacetic acid and the like.
The amounts of the acyloxysilane as the component (d) and the carboxylic acid as the component (e) are preferably in the ranges from 5 to 80% by weight and up to 50% by weight, respectively, each based on the amount of the component (c). When the amount of the acyloxysilane is smaller than the above, the pot life of the resultant composition cannot be extended sufficiently while larger amounts of the acyloxysilane than above result in an excessively high effect of retarding the reaction and, consequently, in an undesirably slow curing velocity or almost no curing. It has been found that the pot life of the composition as defined below reaches a maximum with a suitable amount of the acyloxysilane and decreases by further increase of the amount of the acyloxysilane while the curing velocity decreases steadily with the increase of the amount of the acyloxysilane. The pot life of the compositions can be extended sufficiently by the use of the above specified amount of the component (d) but the combined use of the component (e) with the component (d) gives further enhanced effect of pot life extension although an excessively large amount of the component (e) over 50% by weight based on the component (c) leads to the same disadvantages as with too large amounts of the component (d).
The organopolysiloxane composition of the present invention can be prepared by merely blending the components (a) to (e) uniformly and the composition is readily cured by heating at an elevated temperature to give cured products, such as a coating film on a release paper, with excellent properties not affected by the addition of the components (d) and (e) while the velocity of curing at room temperature is very low with sufficiently extended pot life of the composition.
It is optional that the composition of the present invention is used as dispersed in or diluted with an organic solvent according to need and the organic solvent suitable for such a purpose is exemplified by toluene, xylene, methylethylketone, technical grade gasoline and the like.
The present invention presents a means to almost completely solve the problems in the prior art methods of pot life extension of the organopolysiloxane compositions curable by condensation reaction such as the addition of a large volume of organic solvents or the use of acetic acid and the like. The largest advantage obtained by the present invention is that the effect of the extension of the pot life is very high so that the pot life of the inventive composition is several times or even several tens of times longer than in the similar compositions of the prior art contributing to the reduction of the number of preparations of the ready-mixed compositions and to the stable running of the machines over a long period of time for the process using the organopolysiloxane composition. Further, as a result of the very remarkable effectiveness of pot life extension obtained in the inventive compositions, the retarder components (d) and (e) are used in so small amounts that these components have almost no influence on the concentration of the composition with consequent applicability to the high-solid compositions or solvent-free compositions by complete elimination or reduction of the necessity of the troublesome use of organic solvents. This advantage is very great from the standpoint of preventing environmental pollution and decreasing the danger of fire or explosion as well as from the standpoint of saving of natural resources.
The second advantage obtained by the present invention is that no adverse effects are given on the properties of the films of the cured organopolysiloxane composition unless too much amount of the component (d) is used. This means that the pot life of the composition can be sufficiently extended with no adverse effects on the heat-curability, peeling resistance and residual adhesiveness when used as a coating material on release papers and the adhesion and the mold releasability when used as a releasing agent.
The third advantage obtained by the present invention is that the principle of the inventive composition is applicable also to the organopolysiloxane compositions of aqueous emulsion type. In an organopolysiloxane composition of aqueous emulsion type used as a coating material on release papers, for example, the retarder components may be admixed in the aqueous medium or in the so-called self-emulsifiable catalyst mix to exhibit the retarding effect on the condensation reaction. Thus a possibility is given of the extension of the pot life of aqueous emulsion type organopolysiloxane compositions hitherto considered as almost impossible.
It is also noteworthy that the addition of the acyloxysilane as the component (d) brings about an unexpected advantage in the manufacturing process of release papers since, different from the conventional organopolysiloxanes of similar types, no adverse effects are given on the peeling resistance of the release paper products even with a delay in the coating and heat-curing of the composition up to 24 hours or longer after admixing of the curing catalyst into the composition.
Further an additional advantage is obtained in that the principle of retardation of the present invention is applicable regardless of the types of the catalysts or catalyst systems. For example, the condensation catalyst formulated in the inventive compositions may be any one of dibutyltin dioctoate, dibutyltin diacetate, zinc octoate, tetrabutyl titanate and the like.
In addition, the established interrelationship between the amounts of the retarder components and the pot life of the composition permits the adequate control of the curing time of the organopolysiloxane rubbers and the like by using an appropriate amount of the retarder components.
As is understood by the description above given, the compositions of the present invention may include those silicone products of not only solution types but also products of aqueous emulsion types and solvent-free products.
Following examples are given to illustrate the present invention in further detail, in which parts are all given by parts by weight and the values of viscosity are those measured at 25° C. unless otherwise mentioned.
The procedures for the determination of the pot life, peeling resistance and residual adhesiveness are as follows.
Pot life
The composition after admixing of the metal salt of an organic acid as the curing catalyst was kept for a length of time and then applied evenly to the surface of a polyethylene-laminated paper in a coating amount of 0.8 g/m 2 as organopolysiloxane. The thus obtained coated paper was heated in an air oven at 180° C. for 30 seconds to cure the organopolysiloxane composition to determine the longest time of standing, i.e. pot life, from the admixing of the catalyst to the coating of the paper with the composition capable of giving a curable coating layer. Whether or not the coating layer had been cured by heating was determined by rubbing the surface of the coating layer with a finger tip and, if the coating layer was readily removed by this rubbing test, it was recorded as uncured. When the composition became gelled to such an extent that the coating therewith was no longer possible, the time to the gellation was recorded as the pot life.
Peeling resistance
A polyethylene-laminated paper coated with the organopolysiloxane composition was heated in an air oven at 180° C. for 30 seconds to cure the composition into a coating layer of about 0.8 g/m 2 as organopolysiloxane. After standing at 23° C. for 24 hours in an atmosphere with a relative humidity of 65%, the thus obtained coated paper was further coated with a pressure-sensitive acrylic adhesive of solution type BPS-5127 (product of Toyo Ink Seizo Co., Japan) in a coating amount of about 130 μm thickness and kept at 23° C. for 15 minutes for drying. Then a paper for recorder chart was laid on the adhesive surface and adhesively bonded by pressing with a roller weighing 2 kg which was moved once to the right and left on the paper followed by keeping at 23° C. for 3 hours in an atmosphere with a relative humidity of 65%. The thus bonded paper was peeled at a speed of 30 mm/minute in the 180° C. direction to determine the resistance against peeling which was recorded in grams per 5 cm.
Residual adhesiveness (by tape method)
A polyethylene-laminated paper was coated with the organopolysiloxane composition in the same manner as in the test for peeling resistance above described and kept at 23° C. for 24 hours in an atmosphere with a relative humidity of 65%. An adhesive tape, Scotch Tape No. 28 (product of Minesota Mining & Manufacturing Co.) of 1/2 inch width was attached to the silicone-coated surface and bonded by pressing with a load of 20 g/cm 2 for 20 hours at 70° C. and then kept at 23° C. for 4 hours in an atmosphere with a relative humidity of 65%. Then the adhesive tape was taken by peeling and attached again on to the surface of a stainless steel plate by pressing with a roller weighing 2 kg which was moved once to the right and left. After keeping at 23° C. for 30 minutes in an atmosphere with a relative humidity of 65%, the adhesive tape was peeled at a speed of 30 mm/minute in the 180° direction and the resistance against peeling was recorded.
The above obtained value of the peeling resistance was compared with the reference value, which was obtained with the same tape but taken from the surface of a plate of polytetrafluoroethylene resin instead of the silicone-coated surface, the other conditions of the procedure being the same as in the above, and expressed in percentages to be recorded as the value of the residual adhesiveness.
Example 1
A curable composition was prepared by uniformly blending 49.5 parts of a dimethylpolysiloxane terminated at both chain ends with hydroxy groups and having a viscosity of 700 centistokes, 0.5 part of a methylhydrogenpolysiloxane expressed by the structural formula ##STR4## having a viscosity of 20 centistokes, 50 parts of toluene and 5 parts of dibutyltin diacetate. The pot life of this compostion at 25° C. was about 20 minutes.
Into the composition prepared in the same formulation as above were added trimethylacetoxysilane and trichloracetic acid in amounts varied as indicated in Table 1 below and the pot life of the composition was examined to give the results as set out in the same table. As is evident from the table, remarkable extension of the pot life was achieved by the addition of trimethylacetoxysilane and trichloroacetic acid.
Table 1______________________________________Trimethylacetoxy- Trichloroacetic Pot life,silane, parts acid, parts minutes______________________________________0 0 202.5 0.20 1502.5 0.24 2500.7 1.20 360______________________________________
Example 2
A curable composition was prepared by uniformly blending 43 parts of a dimethylpolysiloxane terminated at both chain ends with hydroxy groups and having a viscosity of 600 centistokes, 7 parts of a methylhydrogenpolysiloxane expressed by the structural formula ##STR5## having a viscosity of 15 centistokes, 40 parts of technical grade gasoline and 5 parts of dibutyltin dioctoate. The pot life of this composition was about 50 minutes at 25° C.
Into the composition prepared in the same formulation as above were added trimethylacetoxysilane and acetic acid in amounts varied as indicated in Table 2 below and the pot life of the composition was examined to give the results as set out in the same table. As is evident from the table, remarkable extension of the pot life is achieved by the addition of trimethylacetoxysilane and acetic acid.
Table 2______________________________________Trimethylacetoxy- Acetic acid, Pot life,silane, parts parts minutes______________________________________0 0 505 0 1705 1 300______________________________________
EXAMPLE 3
Curable compositions were prepared in the same formulation as in Example 2 except that the trimethylacetoxysilane and acetic acid were replaced with 5 parts of an acyloxysilane and 1 part of a carboxylic acid as indicated in Table 3 below to give the values of the pot life at 25° C. as set out in the same table.
Table 3______________________________________ Pot life,Acyloxysilane Carboxylic acid minutes______________________________________Dimethylvinyl Acetic acid 270acetoxysilaneTrimethylbutan- Trichloroacetic acid 360oyloxysilaneDimethylphenyl Trifluoroacetic acid 330acetoxysilaneTrimethyllauroyl- Trichloroacetic acid 230oxysilaneTrimethylbutanoyl- Benzoic acid 250oxysilane______________________________________
EXAMPLE 4
An aqueous emulsion of an organopolysiloxane curable by condensation reaction was prepared by uniformly blending 9 parts of a dimethylpolysiloxane terminated at both chain ends with hydroxy groups and having a viscosity of 2,000 centistokes, 1 part of the same methylhydrogenpolysiloxane as used in Example 2, 5 parts of toluene, 1 part of a nonionic surface active agent Newcol 131C (product of Nippon Emulsifier Co.), 81 parts of water and 0.1 part of acetic acid.
On the other hand, a self-emulsifiable catalyst mix was prepared by uniformly blending 1 part of dibutyltin dioctoate, 1 part of toluene and 1 part of the same nonionic surface active agent as above.
A silicone emulsion for release paper coating was prepared by uniformly blending the above prepared organopolysiloxane emulsion and the catalyst mix and found to have a pot life of about 20 minutes at 25° C.
Five other silicone emulsions for release paper coating were prepared in the same formulation as above except that the catalyst mixes were admixed in advance with trimethylacetoxysilane in varied amounts as indicated in Table 4 below, in which the values of the pot life at 25° C. are also given. The values of the peeling resistance and the residual adhesiveness were determined after 1, 3, 5 or 24 hours of keeping of the emulsions after admixing of the catalyst mix and the results are set out in Table 4.
Table 4__________________________________________________________________________ Peeling resistance inTrimethyl- g/5 cm determined Residual adhesivenessacetoxy after: in % determined after:Emulsionsilane, Pot life, 1 3 5 24 1 3 5 24No. parts hours hr. hrs. hrs. hrs. hr. hrs. hrs. hrs.__________________________________________________________________________1 0 2 26 147 200 220 87 94 95 942 0.12 5 18 14 18 185 87 92 93 923 0.24 24 23 12 16 27 88 90 91 904 0.34 72 20 13 20 20 87 90 90 885 0.42 24 19 16 21 22 87 88 80 816 0.60 24 20 17 22 21 86 87 81 80__________________________________________________________________________
EXAMPLE 5
A curable composition was prepared by uniformly blending 100 parts of a dimethylpolysiloxane terminated at both chain ends with hydroxy groups and having a viscosity of 1,000 centistokes, 0.6 part of a methylhydrogenpolysiloxane expressed by the structural formula ##STR6## having a viscosity of 20 centistokes and 5 parts of dibutyltin diacetate. The pot life of this composition was about 33 minutes at 25° C.
Into the composition prepared in the same formulation as above were admixed trimethylacetoxysilane and trichloroacetic acid in varied amounts as indicated in Table 5 below and the pot life of these compositions was examined to give the results as set out in the same table.
Table 5______________________________________Trimethylacetoxy- Trichloroacetic Pot life,silane, parts acid, parts minutes______________________________________0 0 330 1.5 533.5 0 2341.0 0.8 400______________________________________ | Organopolysiloxane compositions are provided which are curable by condensation reaction taking place between a first component, hydroxy-terminated diorganopolysiloxane and a second component, organohydrogenpolysiloxane by aid of a third component, a condensation catalyst, and which are made to have their pot life extended by adding a fourth component, acyloxysilane, optionally in combination with a carboxylic acid, as a condensation retarder. The addition of the retarder does not adversely effect the curing velocity of the composition even at an elevated temperature and the properties of the cured composition. | 2 |
FIELD OF THE INVENTION
[0001] The present invention relates to systems for lubricating a pneumatically-driven power tool and specifically to an in-line lubricator configured to introduce a predetermined amount of lubricant into the compressed airflow which drives the motor.
BACKGROUND OF THE INVENTION
[0002] Pneumatic tools such as screwdrivers, nailers and the like, generally comprise a body housing a pneumatic motor connected by a kinematic coupling to a drive member. The body includes a handle connected to a source of fluid under pressure and a trigger for controlling the entry of fluid, such as compressed air, to drive the motor.
[0003] In many cases, it is desirable to introduce lubricant into the compressed air flow for lubricating the motor or other parts of the tool. A number of conventional arrangements provide lubrication consistently into the flow of air when the device is in operation. Often it is not desirable to provide a constant flow of lubrication into the components of the tool. Thus, an in-line lubricator which selectively introduces a metered amount of lubrication into the compressed airflow is needed.
SUMMARY OF THE INVENTION
[0004] It is a general object of the present invention to provide a method and apparatus which provide an in-line lubricator for transferring a predetermined amount of fluid from a first location to a second location.
[0005] In one form, the present invention provides an apparatus including a body defining a working channel and a fluid reservoir. The fluid reservoir contains lubricating fluid therewithin. The apparatus further includes an actuator having an elongated body including a transfer cavity. The transfer cavity is in fluid communication with the fluid reservoir in a first position. The actuator is movable to a second position whereby the transfer cavity dispenses a predetermined amount of lubricating fluid into the working channel.
[0006] In another form, the present invention provides an arrangement for delivering a predetermined amount of lubricating fluid from a first location to a second location. The apparatus includes a body defining a working channel and fluid reservoir, the fluid reservoir containing lubricating fluid therewithin. The arrangement further includes a piston actuable between a first position and a second position. The piston includes a collection chamber in fluid communication with and operable to accumulate fluid from the fluid reservoir in the first position and dispense fluid therefrom into the working channel in the second position.
[0007] Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limited the scope of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:
[0009] [0009]FIG. 1 is a cutaway view of the in-line lubricator shown in the first position.
[0010] [0010]FIG. 2 is a cutaway view of the in-line lubricator shown in the second position.
[0011] [0011]FIG. 3 is a cutaway view of the in-line lubricator with the actuator removed.
[0012] [0012]FIG. 4 is a side view of the actuator.
[0013] [0013]FIG. 5 is a detailed view of the second end of the actuator.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0014] The following description of the preferred embodiment is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.
[0015] With initial reference to FIG. 1, the in-line lubricator according to the teachings of the present invention is illustrated and identified at reference numeral 10 . The in-line lubricator 10 generally includes a body 12 and actuator or piston 14 . As particularly shown, body 12 defines a first cavity or fluid reservoir 16 and a second cavity or working passageway 18 . As presently preferred, the volume of fluid reservoir 16 is approximately one-eighth (⅛) of an ounce.
[0016] With continued reference to FIGS. 1 - 3 , the body 12 will be described in more detail. In the exemplary embodiment the fluid reservoir 16 contains a lubricating fluid such as oil and is oriented in a parallel relationship to the working passageway 18 which is configured to allow air flow therethrough. Working passageway 18 terminates at each end with threaded apertures adapted to receive a coupling for connecting the in-line lubricator between a compressor or other source of compressed air and a pneumatic tool. While in-line lubricator 10 is illustrated as a separate component from tool and compressor, one skilled in the art would recognize that the present invention could be configured as an integrated part of the tool and/or the compressor.
[0017] With particular reference to FIG. 3, actuator 14 has been removed for illustrative purposes. A first bore 20 extends from an outer surface 26 of body 12 through an inner circumferential wall 28 of fluid reservoir 16 defining first and second diametrically opposed ports 30 , 32 . First bore 20 further extends to an inner circumferential wall 38 of working passageway 18 defining a third port 34 thereat. A second bore 40 extends from outer surface 26 of body 12 to inner circumferential wall 38 of working channel 18 defining passage 44 . Second bore 40 is preferably aligned axially with first bore 20 .
[0018] Actuator 14 will be further described referencing all figures. The actuator 14 is configured to axially slide through first bore 20 between a first position (FIG. 1) and a second position (FIG. 2). Actuator 14 is generally defined by elongated body 50 . First end 52 is defined by head 54 configured to receive handle 22 therearound. Handle 22 may be press fit onto head 54 or otherwise suitably secured to head 54 by a threaded connection or other like fastening means. First and second collars 56 , 58 are axially separated by first neck 60 . A transfer cavity or collection chamber 66 is axially displaced from second collar 58 by second neck 68 . A second end 70 of elongated body 50 is defined by disk 72 which is axially displaced from collection chamber 66 by third neck 74 . A ridge 76 radially extends from disk 72 defining a step thereat to form a spring. Seat 78 as further described hereafter.
[0019] First neck 60 includes a first O-ring 80 journalled therearound for engagement with circumferential wall 24 of first bore 20 . First O-ring 80 provides an interference fit between actuator 14 and circumferential wall 24 of bore 20 creating a seal therebetween. Second O-ring 82 provides an interference fit between actuator 14 and bore 20 when the actuator 14 is in the second position creating a seal therebetween to inhibit fluid flow from the fluid reservoir 16 to the working passageway 18 . Second O-ring 82 is disengaged from bore 20 in the first position. Third O-ring 84 provides an interference fit between actuator 14 and circumferential wall 36 of bore 20 when the actuator is in the first position creating a seal therebetween to inhibit fluid flow from the fluid reservoir 16 to the working passageway 18 . Third O-ring 84 is disengaged from bore 20 in the second position.
[0020] Turning now to FIG. 5, collection chamber 66 is defined by the area between opposing radiused surfaces 86 , 88 of ribs 90 , 92 . Collection chamber 66 further includes an inner boundary defined by circumferential wall 94 and an outer boundary defined as circumferential wall 36 . Thus, the volume of collection chamber 60 is the annulus defined by radiused surfaces 86 , 88 and circumferential walls 36 , 94 . As presently preferred the volume of collection chamber 16 is approximately 0.001 in 3 or approximately the equivalent of one (1) drop of oil. However, One skilled in the art will recognize that the volume of collection chamber may be adjusted in accordance with the given application.
[0021] Referencing FIG. 1, a spring 96 biases disk 72 into engagement with inner circumferential wall 38 of working channel 18 around third port 34 . Spring 96 is supported at one end by spring set 78 of disk 72 and at the opposite end by a threaded plug 98 disposed in passage 44 and axially biases actuator 14 in the first or closed position. Plug 98 is removable from passage 44 to provide access to working chamber 18 for assembly of in-line lubricator 10 and for drainage purposes or other maintenance needs.
[0022] The operation of in-line lubricator 10 will now be described. Actuator 14 is linearly actuable from a first position (FIG. 1) to a second position (FIG. 2). To displace actuator 14 from a first position to a second position, the handle 22 is from a location laterally displaced from the outer wall 26 of body 12 , i.e. the first position to a location laterally engaged with outer wall 26 , i.e. the second position. While handle 22 is shown as a cylindrical disk, one skilled in the art will recognize that other geometrical configurations may be used or alternately a cantilever arm extending at various orientations relative to body 12 may be used.
[0023] In the first position, fluid within the fluid reservoir 16 occupies the area defining collection chamber 66 . Fluid also fills an annular trough 74 bounded by third O-ring 84 and the circumferential wall 36 of bore 20 as represented by the flow arrows in FIG. 1. Accordingly, collection chamber 66 is filled with a volume of oil equal to one (1) drop as the actuator 14 is displaced from the first position to the second position until second O-ring 82 engages second port 32 . Displacement of actuator allows fluid contained in the collection chamber 66 to be emitted from third port 34 whereby the fluid is deposited into working passageway 18 upon disengagement of third O-ring 84 from third port 34 . When air flows through working passageway 18 , the oil spring 96 returns actuator 14 to the first position upon release of the handle 22 .
[0024] The detailed description of the invention set forth above is merely exemplary in nature and, thus, the present invention may include variations that do not depart from the spirit and scope of the invention as defined in the appended claims. | An in-line lubricator for a pneumatic tool system includes a body defining a fluid reservoir and a working passageway and an actuator positionable within the body. The actuator includes an elongated body having a transfer cavity formed therein which is in fluid communication with the fluid reservoir when the actuator is in a first position and which is in fluid communication with the working passageway when the actuator is in the second position. Movement of the actuator from the first position to the second position transports a predetermined amount of fluid from the fluid reservoir into the working passageway. | 5 |
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a detection apparatus, and more particularly to a detection apparatus set up in a cleaning tank, and is adjustable according to the size thereof.
[0003] 2. Description of the Related Art
[0004] A complete semiconductor process includes many steps such as film deposition, lithography, and etching. Large quantities of materials and solutions are used for manufacturing or washing, while mostly water is used in a wet bench.
[0005] Acidic or chemical solvents such as H 2 SO 4 , HF and H 3 PO 4 are the principal solutions used in etching or dissolving in semiconductor processes. Residue of acidic or chemical solvents easily remains on the wafer, which must then be thoroughly cleaned with large quantities of deionized water (DI water).
[0006] The chemical wet bench includes a cleaning tank, a cassette, and a megasonic device.
[0007] In FIG. 1, wafers 101 are vertically disposed in the cassette 102 . The two wafers 101 are separated by a divider 102 a . The wafers 101 are supported in an upright position by the divider 102 a.
[0008] In FIG. 2, the cassette 102 and the wafers 101 are placed in a cleaning tank 105 . The cleaning tank 105 has a bottom portion 104 provided with air holes 104 a.
[0009] A megasonic device 106 comprises a megasonic tank 106 a . Cleaning solution 107 is placed in the megasonic tank 106 a . The megasonic device 106 is coupled beneath the cleaning tank 105 .
[0010] The cleaning solution 107 , at megasonic energy levels, is injected into the cleaning tank 105 through the air holes 104 a of the bottom portion 104 .
[0011] [0011]FIG. 3 shows a cleaning tank 105 , in which the cassette 102 is placed and a megasonic device 106 , which includes megasonic tank 106 a containing DI water 107 , coupled beneath the cleaning tank 105 .
[0012] The DI water 107 , at megasonic energy levels, is injected from megasonic tank 106 a into the cleaning tank 105 via the air holes of the bottom portion 104 when the megasonic device 106 is turned on.
[0013] The cleaning tank 105 contains DI water 107 and the wafers 101 . The cleaning tank 105 further comprises a discharging portion (not shown). Surplus DI water 107 is discharged by the discharging portion. Residue on the wafers 101 cannot be thoroughly removed if the megasonic device 106 provides insufficient megasonic energy due to damage.
[0014] There are several commercially available detectors to measure the megasonic energy levels of the DI water 107 in the cleaning tank 105 . The detector is placed in the activated cleaning tank 105 in a predetermined position, and the megasonic energy levels of the DI water 107 in the cleaning tank 105 are directly measured by the detector. The detector can be, for example, a sound level meter.
[0015] Because commercially available detectors require manual operation and estimation of distance by the operator, error can result.
SUMMARY OF THE INVENTION
[0016] Accordingly, the object of the present invention is to provide a detection apparatus for a cleaning tank. The detection apparatus can be adjusted according to the dimensions of the cleaning tank. In addition, the detection apparatus can detect the megasonic energy levels in the cleaning tank in a predetermined position when the coordinate values of the position are set.
[0017] The present invention provides an adjustable detection apparatus comprising a first holding member, a second holding member, and a detection device. The first holding member has a first sliding area, and the second holding member is moveable in the first sliding area. The second holding member has a second sliding area, and the detection device is moveable in the second sliding area.
[0018] The present invention also provides an adjustable detection apparatus, for detecting the megasonic energy levels of the clean liquid in a cleaning tank, comprises a first holding member, a second holding member, and a detection device with a detachable detector. The first holding member has a first sliding area, and the second holding member is moveable in the first sliding area. The second holding member has a second sliding area, and the detection device is moveable in the second sliding area. The detachable detector can measure the megasonic energy levels of the clean liquid in the cleaning tank.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The present invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein:
[0020] [0020]FIG. 1 is a cross section of a cassette of a conventional chemical wet bench;
[0021] [0021]FIG. 2 is a top view of a conventional chemical cleaning machine in which a cassette is displaced;
[0022] [0022]FIG. 3 is a cross section taken along lines A-A of FIG. 2;
[0023] [0023]FIG. 4 a shows an adjustable detection apparatus of the present invention; and
[0024] [0024]FIG. 4 b is a perspective view of the adjustable detection apparatus of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0025] A detailed description of the adjustable detection apparatus of the present invention is given hereafter with reference to FIGS. 4 a and 4 b . FIG. 4 a shows the adjustable detection apparatus of the present invention. FIG. 4 b is a perspective view of the adjustable detection apparatus of the present invention.
[0026] The adjustable detection apparatus comprises first holding members 401 , second holding members 402 , and a detection device 403 . The first holding members 401 are coupled to the second holding members 402 . Running gears (not shown) are sequentially coupled to the first holding members 401 and the second holding members 402 and the detection device 403 to drive the detection device 403 . The running gear can, for example, be a stepping motor.
[0027] The adjustable detection apparatus can be used on a wafer cleaning tank. The first holding members 401 are adjustable according to the length of the cleaning tank, suitable for any size of cleaning tank.
[0028] The first holding members 401 , parallel to each other, each have a sliding area 401 a . The second holding members 402 sequentially have a sliding area 402 a and a sliding member 402 b . The second holding members 402 are parallel to each other, and the second holding member 402 and the first holding member 401 are perpendicular to one another. The detection device 403 has a sliding member 403 a.
[0029] The second holding members 402 are adjustable according to the width of the cleaning tank. The sliding member 402 a is positioned within the sliding area 401 a , such that the holding members 402 are coupled to the holding members 401 .
[0030] The sliding member 403 a is positioned within the sliding area 402 a , so that the detection device 403 is coupled to the second holding members 402 .
[0031] The running gear coupled to the first holding members 401 is turned on to drive the second holding members 402 , followed by the sliding member 402 b moving in the sliding area 401 a.
[0032] The running gear coupled to the second holding members 402 is turned on to drive the detection device 403 , followed by the sliding member 403 a moving in the sliding area 402 a.
[0033] The detector 404 is fixed in the detection device 403 via a hole 403 b thereof. The hole 403 b is adjustable according to the diameter of the detector 404 . After the detector 404 is fixed in the detection device 403 via the hole 403 c , the running gear, coupled to the detection device 403 , is turned on to drive the detector 404 up or down. The detector 404 can be a commercially available sound level meter.
[0034] The detecting method applied to the megasonic cleaning tank of the present invention is herein described.
[0035] First, a value that indicates a coordinate is input. For example, the coordinate value can be (25, 17, and 4) or (25, 33, 4).
[0036] Next, the running gears (not shown) are turned on to sequentially drive the first holding members 401 and the second holding members 402 to the position indicated by the coordinate in the X-Y. For example, after the running gear is turned on, the detection device 403 is driven to the position indicated by the coordinates (25, 17).
[0037] After that, the running gear coupled to the detection device 403 is turned on to drive the detector 404 on the Z-axis to arrive at the predetermined coordinates. For example, after the running gear is turned on to drive the detector 404 , the detector 404 is driven in the Z-direction to the position indicated by the coordinate (25, 17, and 4).
[0038] By this means, the detector 404 is moved into detecting position. The apparatus of the present invention can bring the detector to any predetermined position to perform detection. The results can then be compared to each other.
[0039] After detection is complete and the results of the detection are recorded, the running gears are turned on again to drive the first holding members 401 and the second holding members 402 and the detection device 403 to the, next desired coordinates.
[0040] For example, if the next coordinate values are (25, 33, 4), the X-value of next position is the same number, but the Y-values of (25, 33, 4) and (25, 17, 4) are different. Thus the running gear on the holding member that controls the movement of the detection apparatus in the Y-axis is turned on the holding member to Y=33 from Y=17. The Z-value of the next position is the same number as well, so the running gear coupled to the detection device 403 is not turned on to drive the detector 404 . Then, the megasonic energy levels of the position at coordinates (25, 33, and 4) are detected by the detector 404 .
[0041] The adjustable detection apparatus detects the megasonic energy levels of the clean liquid, such as DI water or chemical solution, when wafers are being cleaned, so real-time detecting results of the clean liquid are recorded.
[0042] The adjustable detection apparatus can detect the megasonic energy levels of the clean liquid at any position in the cleaning tank. The position of the cleaning tank can be selected by any controlling apparatus or user.
[0043] The adjustable detection apparatus of the present invention is not limited to detection of the megasonic energy levels of the clean liquid of the cleaning tank, and can be used in any suitable device. Furthermore, other types of detection can be performed in the cleaning tank.
[0044] While the invention has been described by way of example and in terms of the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements. | An adjustable detection apparatus. The apparatus includes a first holding member and a second holding member and a detection device. The first holding member has a first sliding area, in which the second holding member is moveable. The second holding member has a second sliding area. The detection device comprises a detachable detector, wherein the detection device is moveable in the second sliding area. | 6 |
This is a division of application Ser. No. 475,579 filed June 3, 1974.
BACKGROUND OF THE INVENTION
The backfilling of sewers, embankments, structures and utility trenches, for example electrical, gas and water conduits, has often created a problem in the past. This is particularly true where, for example, a pavement or other structure must be placed over a backfilled sewer. If a sewer line was installed by using, for example, an open trench method of construction and if poor soil conditions were present, the normal method of construction to obtain the desired compaction of the backfill material was to remove the original soil and replace it with sand, the original material or other specified backfill soil. In addition, it was often necessary to backfill in layers, often as small as three inch layers, and then mechanically compact these layers. While the results were satisfactory this was a very expensive method of construction.
A similar problem was encountered if the soil bedding was so poor that it had to be removed and replaced with an adequate bedding material for the conduit. It is very important to have a proper bedding under conduits so that the resulting forces are equalized throughout the length of the conduit. For example, if rigid pipe is utilized as the conduit material, and if the bedding does not uniformly support the conduit throughout its length, there is a tendency for the conduit to shear or otherwise fail. In the case of flexible pipe, proper backfill is necessary to insure passive resistance pressure, otherwise the pipe will fail by excessive deflection.
To backfill the trench with, for example, a concrete is also not a proper solution. For example, if a sanitary sewer is being backfilled, and the backfill material is concrete, it is very difficult if not impossible to dig downwardly through the concrete to either repair a break in the line, install a lateral sewer connection into the main line, or make a house tap.
The present invention is directed to solving the above problems and consists of a controlled density fill material. The controlled density fill material, while including Portland cement as one of its constituents, is not a concrete as the term is normally used in the construction industry. A conventional concrete has an average concrete comparison 28-day compressive strength of 4000 psi while the controlled density fill material, according to the present invention, has a compressive strength preferably less than 1600 psi. In fact, when utilized in backfilling a sewer conduit, the preferred material, according to the present invention, has a compressive strength in the range of 200 psi.
On the other hand, the controlled density fill material, according to the present invention, is not a soil as that term is typically used in the construction industry. Rather than having to compact individual layers of the controlled density fill material, according to the present invention, one needs only to place the mix into the trench. The material, because it does not have the structural strength of concrete, may be re-excavated, for example, by using a trencher, in order to reach the pipe to make a repair or to make a connection for a future lateral line.
Furthermore, because the controlled density fill material does not have the rigid structural strength of concrete, it is also an excellent material for use in backfilling adjacent a structure, for example against a bridge abutment. It may also be placed in embankments in place of the customary earth compaction system of construction.
SUMMARY OF THE INVENTION
The present invention relates to a controlled density fill material and a method of using such fill material. The material is a composition which has a compressive strength of not greater than about 1600 psi. The controlled density fill material, according to the present invention, comprises 3% to 6% by weight of Portland cement, 1% to 4% by weight of fly ash, 75% to 90% by weight of aggregate and 5% to 15% by weight of water. In its broadest form, the controlled density fill material comprises 2% to 6% by weight of Portland cement, 1% to 10% by weight of fly ash, 70% to 90% by weight of aggregate and 5% to 15% by weight of water.
After the original soil is removed or an original structure built, it is replaced with controlled density fill material, according to the present invention, or in the alternative such fill material is used as backfill around structures or for embankments. The controlled density fill material does not experience the settlement that is common with conventional soil backfill material.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The controlled density fill material, according to the present invention, is neither a concrete nor a soil. The fill material is generally comprised of Portland cement, fly ash, aggregate and water. However, the fill material made from these ingredients has a compressive strength preferably below 1600 psi and often as low as 100 psi.
Portland, cement -- fly ash compositions are well known in the prior art. Nelles, U.S. Pat. No. 2,250,107 discloses a concrete composition including Portland cement, fly ash and aggregate. However, the Nelles disclosure is directed to a structural concrete having compressive strengths over 2000 psi.
Keyishian, U.S. Pat. No. 2,622,989 is directed to a cementitious structural composition which includes Portland cement, fly ash and aggregate. This patent discloses the use of such a cementitious structural composition in structural forms such as the building of blocks, panels and the construction of road surfaces.
Other uses of fly ash compositions, including the prior art usage as a soil stabilizer for roadway construction, are disclosed in a Bureau of Mines Information Circular No. 8483 entitled "Fly Ash Utilization: A Summary of Applications and Technology," John D. Capp and John D. Spencer (1970).
The preferred controlled density fill material, according to the present invention, has a compressive strength of less than 1600 psi and has the range of ingredients indicated below in Table A.
TABLE A______________________________________Material Percent by Weight______________________________________Portland Cement 2 - 6Fly Ash 1 - 4Selected Aggregate 75 - 90Water 5 - 15______________________________________
Fly ash, as used in the present specification and claims, includes any ash residue from the burning of coal, including cinder material and bottom ash as well as the gray, finely divided ash which is collected by electrostatic precipitators or mechanical collectors in, for example, a power plant operation. A commercially available fly ash suitable for use in the instant invention is designated as Trenton Channel Fly Ash. The Trenton Channel Fly Ash analysis is indicated below in Table B.
TABLE B______________________________________TRENTON CHANNEL FLY ASHChemical Analysis Percent of Dry Weight______________________________________Fe.sub.2 O.sub.3 21.0Al.sub.2 O.sub.3 25.0MgO 1.0CaO 1.8Na.sub.2 O 0.4K.sub.2 O 1.5TiO.sub.2 1.3SiO.sub.2 48.0 100.0Loss on ignition 5.89Actual Carbon 5.43pH 10.4Specific Gravity 2.41Moisture 0.28______________________________________
The Portland cement utilized in the controlled density fill material, according to the present invention, is normally a Type I cement, certified to meet the requirements of ASTM C150. For example, a Huron Type I cement was utilized in the controlled density fill material, which is the subject matter of the examples reported below. However, other types of Portland Cement may be utilized.
The aggregates utilized are various types of granular materials that can be used as fillers. The selected aggregates would, of course, be locally selected materials. By way of examples, two types of aggregates which have been used in connection with controlled density fill materials, according to the present invention, are berm aggregates, obtained from a limestone processing company and Maumee Estuary sand. By way of examples, laboratory data relating to the berm aggregate is indicated below in Table C and data relating to the Maumee Estuary sand is indicated below in Table D.
TABLE C______________________________________BERM AGGREGATEMoisture Content, as used 2.4%Average Absorption 1.3%Total Percent Retained on 3/4" 8.0%Total Percent Retained on 1/2" 32.0%Total Percent Retained on 3/8" 57.0%Total Percent Retained on #4 78.0%Total Percent Retained on #8 90.0%Total Percent Retained on #16 91.0%Total Percent Retained on #30 94.0%Total Percent Retained on #50 96.0%Total Percent Retained on #100 97.0%______________________________________
TABLE D______________________________________MAUMEE ESTUARY SANDMoisture Content, as used 4.2%Absorption 1.3%Total Percent Retained on 3/8" 0%Total Percent Retained on #4 2.0%Total Percent Retained on #8 12.0%Total Percent Retained on #16 18.0%Total Percent Retained on #30 41.0%Total Percent Retained on #50 73.0%Total Percent Retained on #100 91.0%Fineness Modulus 2.37%______________________________________
Many other types of granular materials may be utilized as aggregates in the fill material, according to the present invention.
The controlled density fill material may be utilized for several uses, however, all of these uses require a compressive strength preferably below 1600 psi.
One use is as a backfill material when backfilling a sewer trench which will ultimately be beneath a pavement structure. In this situation, the soil is first excavated and the sewer conduit laid to its proper grade. The controlled density backfill material (see Example 1) is lowered or dumped into the trench over the sewer conduit and the trench is filled to its desired heighth. A concrete comparison 28-day compressive strength of this material is approximately 200 psi. This slow strength allows the material to be recut or re-excavated easily with, for example, a backhole if it is necessary to make connections or repair the sewer conduit in the future.
The conduit backfill material preferably has a concrete comparison 28-day compressive strength of between 100 psi and 300 psi. The range of ingredients by percentage of total weight are as follows: 2% to 5% by weight of Portland cement; 2% and 9% by weight of fly ash; 74% to 86% by weight of aggregates; and 8% to 13% by weight of water.
EXAMPLE 1
SEWER BACKFILL UNDER PAVEMENT STRUCTURE
a. Concrete comparison 28-day compressive strength of 200 psi.
______________________________________Mix proportions - per cubic yard measure.Material Weight (lb.) % Total Weight (lb.)______________________________________Portland Cement 167 4.0Fly Ash 111 2.6Selected Aggregate 3400 82.4Water 450 11.0 4128 100.0______________________________________
b. Requirements
Required 120 pcf. density backfill to be placed in sewer cut. Material strength is regulated to allow for lateral sewer cuts and future sewer placement of laterals. Unit weight of mix is 138 pcf.
c. Mixing procedures
Conventional ready mix operation. Delivery to project site in ready mix truck or dump truck.
d. Construction procedure
Actual backfill placement consists of dumping material into sewer trench. No placement operations required or labor other than material flow direction.
Another use of the present material is as an embankment fill or as a support fill around structures, for example, buildings or bridges. Referring to Example 2, below, a concrete comparison 28-day compressive strength of approximately 1000 psi is required. Forms are provided, either constructed forms or earth forms, and the material is normally delivered to the job site by truck. The material is then placed in the forms. This material has uniform density in its entirety which is an improvement over conventional fill practices.
Controlled density fill material which is used as embankment fill, fill for structures or pipe bedding has a range of ingredients by percentage of total weight as follows: 4% to 6% by weight of Portland cement; 2% to 9% by weight of fly ash; 75% to 90% by weight of aggregates; and 6% and 10% by weight of water.
EXAMPLE 2
FILL FOR EMBANKMENT OR AROUND STRUCTURES
a. A concrete comparison 28-day compressive strength of 1000 psi.
______________________________________Mix proportions - cubic yard measure.Material Weight (lb.) % Total Weight (lb.)______________________________________Portland Cement 222 4.8Fly Ash 333 7.3Selected Aggregate 3600 78.7Water 420 9.2 4575 100.0______________________________________
b. Requirements
Required compaction fill for embankments or structural support fill. Unit weight of granular fill and/or compressive strength to be at least 1000 psi at 28 days. Unit weight of designed mix (a) is 151.6 pcf. with strength at 28 days equal to 1014 psi.
c. Mixing procedures
Conventional ready mix operation. Delivery to project site in ready mix truck or dump truck.
d. Construction procedure
Placement consists of controlling fluidity of material is fill. Total fill heights may be placed depending on confinement conditions on the perimeter of the fill.
Another use of controlled density fill material, according to the present invention, is as a designed bedding for pipe. The pipe may be of several types, for example, vitrified clay tiles for sanitary sewers, reinforced concrete pipe for storm sewers, cast iron pipe for water lines and steel gas lines. It is most important that pipe be properly bedded to insure the uniform distribution of forces along the pipe. The original soil is removed and the controlled density fill material is placed below the pipe or conduit. Referring to Example 3, below, the controlled density fill material for this use has a compressive strength of approximately 1400 psi. While the bedding material is often placed only below the pipe, in some situations it is installed completely around the pipe.
EXAMPLE 3
PIPE SUPPORT OR BEDDING IN TRENCH
a. A concrete comparison 28-day compressive strength of 1400 psi.
______________________________________Mix proportions - cubic yard measure.Material Weight (lb.) % Total Weight (lb.)______________________________________Portland Cement 222 4.8Fly Ash 222 4.8Selected Aggregate 3850 82.9Water 350 7.5 4644 100.0______________________________________
b. Requirements
Required compressive strength of pipe support material --1400 psi at 28 days.
c. Mixing procedures
Conventional ready mix operation. Delivery to project site in ready mix truck or dump truck.
d. Construction procedure
Placement in trench is accomplished by dumping material into trench for placement around pipe.
In the use of flexible pipe bedding and backfilling, controlled density fill is regulated to control the maximum limiting deflection of the pipe. | The invention relates to a controlled density fill material and a method of using such fill material in, for examples, the backfilling of sewers, embankments, structures and utility trenches. The material includes Portland cement, fly ash and aggregates. The material, while having some properties of both, is neither a soil nor a concrete. | 4 |
FIELD OF THE INVENTION
[0001] The present invention is directed to a mounting assembly for mounting blades to a straw chopper rotor.
BACKGROUND OF THE INVENTION
[0002] Straw choppers are typically provided with rotors having a plurality of blades. The blades may be pivotally mounted to the straw chopper rotor (see DE 36 31 485 C) with screws and flanged nuts. The blades are pivotally mounted to mounts. The mounts are welded to the straw chopper rotor. In order to attain a certain quality of chopper output and to keep the power requirement of the chopper within limits, the blades, are provided with cutting edges on both sides. The blades are disassembled after approximately 100 to 200 hours of operation and reassembled after reversing the blades to use the other cutting edge. After this operating time the blade is dull, as a rule, the length of cut becomes larger and the power requirement increases considerably. After a further 100 to 200 hours of operation the old blades are exchanged for new blades.
[0003] The disadvantage of mounting the blades to the mounts by screws and flanged nuts lies in the large amount of time required for changing or reversing the blades. This operation takes approximately four hours for a complete blade exchange for a combine having six straw walkers.
SUMMARY OF THE INVENTION
[0004] When the mounting assembly is assembled a spring brings the locking element in a trapping position in which it cannot be loosened. In this position the normal operation of the straw chopper is performed. The locking element can be brought into a loosening position by the application of an external force, in which it can be loosened from the pin or fastened to the pin. After the removal of the locking element, the blades can be exchanged or turned around rapidly and without any problems.
[0005] In this way the result is that the spring securely traps the locking element during normal operation. In order to attach or exchange the blades, the locking element is brought in a simple way out of the trapping position into the loosening position, in which the locking element can be removed. The pin is removed and the blades can be exchanged or rotated. Following this, the mounting assembly is again attached in reverse order.
[0006] The spring pre-loads the pin in the axial direction that is, it applies a force to it that attempts to draw the ends into the holes from which they are projecting. By moving the pin (manually or by means of a tool) against the force of the spring, the locking element can be moved between the trapping position and the loosening position. A Belleville spring or a helical spring can be used. In the illustrated embodiment the spring is in contact with the inner side of the projecting head of the pin that is adjacent to the shank. It would also be conceivable for the spring to act on the pin in an indirect manner, wherein the spring acts on the locking element and pre-loads it into the trapping position. Furthermore, the spring could also be a torsion spring that pre-loads the pin and/or the locking element in the rotary direction into the trapping position.
[0007] There are a number of possibilities for the attachment of the locking element to the pin. On the one hand the locking element can be applied to the pin in the radial direction. Thereby when the locking arrangement is brought into the loosening position, the locking element is removed by radially sliding it off the pin. This process can be accomplished without any significant loss of time.
[0008] The locking element may be, a cylindrical locking pin that is inserted into a compatible opening in the pin. It can extend with both its ends beyond the pin for trapping the pin in the mounting assembly. In place of a pin, the use of a snap ring is also conceivable, that is inserted into a groove in the pin.
[0009] In the trapping position it is appropriate to limit the axial movement of the locking pin (or the snap ring), so that it does not become loosened from the pin in an undesirable manner. For this purpose, the edge of a recess in an element, such as a bushing, could be used to which the locking pin comes into contact.
[0010] A bayonet attachment could be used for the blades of the straw chopper, in which the locking element is an element that is rigidly attached to the pin or, particularly for repair purposes, a removable element connected to the pin which can be locked and unlocked by a rotation of the pin only in the loosening position. In the trapping position the element is in contact with a counter bearing. Furthermore, in the trapping position the pin is appropriately secured against a rotation relative to the counter bearing so that an undesirable loosening is not to be feared.
[0011] The locking element connected to the pin may be a locking pin extending transverse to the longitudinal axis of the pin, that is inserted in a first rotary position of the pin through the holes and a first groove of a recess in its counter bearing. In a second rotary position of the pin the locking pin is arrested in a second groove of the counter bearing. In order to be able to move the pin between the first and the second rotary position, it must be in the loosening position; in the trapping position no rotation is possible. The counter bearing is preferably arranged in a bushing that is supported in a blade.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] [0012]FIG. 1 shows a harvesting machine with a straw chopper.
[0013] [0013]FIG. 2 shows a perspective exploded view of a first embodiment of a mounting assembly of the blades of the straw chopper.
[0014] [0014]FIG. 3 shows a perspective exploded view of a second embodiment of a mounting assembly of the blades of the straw chopper.
DETAILED DESCRIPTION
[0015] A harvesting machine 10 shown in FIG. 1 in the form of a combine is carried and propelled on front driven wheels and rear steerable wheels 12 and 14 , respectively. The combine is provided with an operator's cab 16 from which it can be controlled by an operator. A grain tank 18 is located behind the operator's cab 16 . The grain tank 18 is provide with a discharge auger 20 for directing harvested grain to a waiting grain truck or cart. The grain tank 18 is supported on a frame 22 . The harvested crop is separated into its large and small components by the threshing assembly. The threshing assembly comprises a rotating threshing cylinder 24 , a stationary concave 26 and a beater 28 . Straw walkers 30 are located downstream form the threshing assembly and receives the large components of the threshed crop. Grain and chaff fall from the threshing concave and the straw walkers and are directed to a grain pan 32 . The grain pan 32 directs the grain and chaff to the cleaning assembly. The cleaning assembly comprises sieves 34 and blower 36 . The blower blows the chaff out the rear of the combine, whereas the cleaned grain is allowed to fall onto the floor of the combine. The cleaned grain is collected and routed to an elevator which lifts the clean grain to the grain tank 18 . The large crop components left over after passing across the straw walkers 30 are passed over a straw guide vane 40 to a straw chopper 42 . Crop standing or lying on the ground is collected by a harvesting assembly and directed to a feeder house 38 . The feeder house 38 conveys the harvested crop past a stone trap to the threshing assembly.
[0016] Although the illustrated embodiment discloses a conventional combine having a transverse threshing cylinder and concave, and straw walkers, the present invention could also be used on combines having rotary threshing and separating units, and other types of harvesting machines requiring a straw chopper.
[0017] The straw chopper 42 comprises a hollow cylindrical rotor 44 having blades 46 distributed over its circumference and transversely over its length. The blades 46 are pivotally coupled to the rotor 44 . The rotor is driven by a drive, not shown, for rotation in housing 48 about an approximately horizontal axis that extends transverse to the direction of operation. The threshed out large crop components are chopped by the blades 46 interacting with the stationary shear bars 50 . The rear of the straw chopper 42 is provided with a distributing arrangement 54 having a number of guide vanes 56 that are located beneath a straw distributor hood 58 .
[0018] [0018]FIGS. 2 and 3 illustrate two embodiments of a mounting assembly for mounting the blades 46 to the rotor 44 . FIG. 2 shows an exploded view of a first embodiment of such a mounting assembly. The blades 46 are equipped with ground edges on their long sides and preferably on their outer ends and are fastened in pairs to a mount 60 that is welded or fastened by other means to the rotor 44 . A blade 46 is located on each side of the mount 60 . The mount 60 extends in the direction of rotation of the rotor 44 . The mount 60 is provided with a hole 62 extending in the axial direction of the rotor 44 . For mounting the blades 46 , a pin 64 , a Belleville spring 66 , bushings 68 , 70 , 72 , 74 as well as a locking piece 76 are used. The bushings 68 , 70 and 72 as well as the blades 46 and the rotor 44 with the mount 60 are elements that are also used with conventional straw choppers 42 . Therefore these are available at favorable cost. In the assembled condition the outer bushings 68 and 74 extend into the holes 78 of the blades 46 , and the inner bushings extend into the hole 62 of the mount 60 . The pin 64 is inserted successively through the central opening of the Belleville spring 66 , the central opening of the first bushing 68 , a hole 78 in the first blade 46 , a central opening in the second bushing 70 , the hole 62 in the mount 60 , a central opening in the third bushing 72 , a hole 78 in the second blade 46 and finally through a corresponding opening in the fourth bushing 74 . In the assembled condition, the pin 64 extends through the aforementioned elements where its head 80 , that is adjacent to the Belleville spring 66 projects radially outward form the shank. The head 80 prevents the pin 64 from sliding through the opening of the Belleville spring 66 . Thereby, the head 80 holds the pin 64 in contact with the Belleville spring 66 , which in turn is in contact with the first bushing 68 . At its opposite end, the pin 64 is retained by the locking piece 76 acting as a locking element which penetrates the opening 82 . The locking piece 76 extends radially from both sides of the pin 64 and is spaced away from the head 80 . The outwardly extending portion of the locking piece 76 is in contact with the outer surface of the fourth bushing 74 which projects beyond the opening 82 . The Belleville spring 66 axially tensions the pin 64 . The tensioned pin 64 is trapped in its axial direction at the fourth bushing 74 and holds together the entire assembly described here.
[0019] In order to prevent the locking pin 76 from loosening and escaping out of the opening 82 , a recess 84 is provided in the fourth bushing 74 which extends radially and which is shaped with approximately rectangular cross section, that is slightly longer than the locking pin 76 and whose width and depth are somewhat larger than the diameter of the locking pin 76 . Thereby the edge of the recess 84 defines the border of the region within which the locking pin 76 can move axially in the recess 84 . Therefore the recess 84 could also be circular in shape, since the azimuthal orientation of the locking pin 76 does not have any significance. Since the pin 64 and the remaining elements for the fastening of the blades 46 are dimensioned in such a way that the Belleville spring 66 is compressed when the opening 82 projects beyond the edge of the recess 84 in the axial direction of the pin 64 . The spring force of the Belleville spring 66 holds the opening 82 and therewith the locking pin 76 within the recess 84 .
[0020] To assembly the mounting assembly of the blades 46 , the blades 46 with the bushings 68 , 70 , 72 and 74 are positioned alongside the hole 62 . Then the pin 64 which has been inserted into the Belleville spring 66 is inserted through the holes that have been aligned with each other. Vise-grip pliers can then be used to squeeze the head 80 of the pin 64 and the fourth bushing 74 compressing the Belleville spring 66 and extending the pin 64 outwardly from the fourth bushing 74 so that the opening 82 projects beyond the fourth bushing 74 . Only after the Bellville spring 66 has been compressed is it possible to insert the locking pin 76 into the opening 82 . The vise-grip pliers is removed and the Belleville spring 66 is unloaded, so that it draws the locking pin 76 into the opening 84 in which it is trapped, fixing the mounting assembly. Preferably the spring deflection of the Belleville spring 66 is so small that when the blades 64 are tilted (in FIG. 1 to the left or to the right) they cannot touch the shear bars 50 . In a further embodiment, the head 80 of the pin 64 and the fourth bushing 74 may be provided with corresponding flats on its outside or a hexagonal shape that is reproduced in the tensioning arrangement (vise-grip pliers or the like), so that the opening 82 and the recess 84 are in alignment, in order to simplify the assembly. The disassembly is performed in the opposite sequence.
[0021] [0021]FIG. 3 shows a second embodiment of a mounting assembly according to the invention, where elements that correspond to the first embodiment are identified with identical reference numbers, while elements that differ have the same reference numbers but are further designated with a prime.
[0022] In contrast to the first embodiment, in the second embodiment the locking pin 76 ′ is rigidly connected with the pin 64 ′. The locking pin 76 ′ is configured, for example, as a spring-type locking pin or a dowel pin with a press fit. It could also be welded, attached with adhesive or soldered to the pin 64 ′. Furthermore the fourth bushing 74 ′ is equipped with a cross-shaped recess 84 ′ that includes a first groove that extends through the bushing 74 ′ and a second groove indexed through 90° thereto, which, however, is configured as a depression, as in the first embodiment. The locking pin 76 ′ prevents the Belleville spring 66 from being lost. In this embodiment all further bushings 68 ′, 70 ′ and 72 ′ must be provided with a slot corresponding to the first groove or a bore, so that the pin 64 ′ with the locking pin 76 ′ can be inserted through it. The head 80 ′ of the pin 64 ′ is preferably provided with an inner (or outer) hexagonal shape or other deformations, in order to make it possible to turn it with a corresponding wrench.
[0023] For the assembly of the mounting assembly the blades 46 and the bushings 68 ′, 70 ′, 72 ′ and 74 ′ are aligned with the hole 62 in the mount 60 . After the insertion of the pin 64 ′, where the locking pin 76 ′ is conducted through the grooves in the bushings 68 ′, 70 ′, 72 ′, and 74 ′, the head 80 ′ of the pin 64 ′ and the fourth bushing 74 ′ the Belleville spring 66 is compressed with an appropriate tool. The pin 64 ′ and/or the fourth bushing 74 ′ is rotated through 90° with a corresponding tool and the tensioning tool is released. Thereby the locking pin 76 ′ comes into contact in the second groove, that is a blind groove, of the recess 84 ′ of the fourth bushing 74 ′ and thereby arrests the mounting assembly. Here the locking element is the locking pin 76 ′ interacting with the fourth bushing 74 ′. Here too, the disassembly is performed in the reverse sequence.
[0024] It should be noted that in both embodiments it would be conceivable that the Belleville spring 66 be attached at any desirable other location in which it forces the locking pin 76 or 76 ′ into the recess 84 or 84 ′. It could be arranged between the second bushing 70 or 70 ′ and the mount 60 (then it is indirectly attached to the pin 64 , 64 ′) or between the mount 60 and the third bushing 72 or 72 ′ (then it acts upon the fourth bushing 74 , 74 ′). It could also, if necessary with the use of appropriate washers, be positioned between the fourth bushing 74 , 74 ′ and the blade 46 shown at left. In all these locations it acts indirectly upon the pin 64 , 64 ′ and/or the fourth bushing 74 , 74 ′ and forces the locking pin into its arresting position in the recess 84 , 84 ′.
[0025] Having described the preferred embodiment, it will become apparent that various modifications can be made without departing from the scope of the invention as defined in the accompanying claims. | A mounting assembly for fastening blades to a straw chopper rotor. The rotor is provided with a plurality of mounts each mount having a rotor mounting hole. The blades are secured to the mounts. Each blade is provide with a blade mounting hole. A pin is inserted into the rotor mounting hole and the blade mounting hole. The pin is provided with a locking element for holding the pin in place. The locking element having a trapping position where it is locked in place and a loosening position wherein the pin can be removed. The locking element is held in its trapping position by a spring. The locking element engaging a recess having an edge for holding the locking element in the trapping position. | 0 |
This application claims priority from U.S. provisional patent application Ser. No. 60/824,281 filed on Aug. 31, 2006.
This invention was made with government support under contract number NNG06LA05C awarded by the National Aeronautics and Space Administration (NASA). The government has certain rights in this invention.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to methods of detecting strain in birefringent materials.
2. Background of the Related Art
Strain is a geometrical expression of deformation caused by the action of stress on a physical body. Strain therefore expresses itself as a change in size and/or shape, and is typically measured as a percentage elongation.
When transparent, isotropic materials are squeezed, bent or stretched to become anisotropic, birefringence can result. Birefringence, or double refraction, is the decomposition of a ray of light into two rays when it passes through certain types of material, such as calcite crystals, depending on the polarization of the light. This effect can occur only if the structure of the material is anisotropic. Many plastics are birefringent, because their molecules are ‘frozen’ in a stretched conformation when the plastic is molded or extruded. Alternatively, many plastics such as cellophane exhibit birefringence when strained.
A pressurized balloon formed of polyethylene film is a good example of a birefringent material that may become strained. One existing method for monitoring balloon strain in flight uses permanent marks on the balloon with a known distance between them at zero strain to determine stretch via a video inspection feed. Another method uses distributed piezoelectric strain gauges on the surface of the balloon and relies on the electrical signal produced in the gauges as the film stretches. A third approach involves the monitoring of differential Global Positioning System (GPS) receivers arrayed around the balloon surface to determine stretch in the film. However, each of these approaches has shortcomings which limit its functionality and practicality for this application.
The use of photogrammetry is currently the most viable method of measuring strain in balloons. As the balloon expands, the distance between marks on the balloon increases and the length increase can be measured directly. However, the requirement that multiple cameras be used for triangulation of point positions complicates this measurement approach significantly. Additionally, measurements can only be taken from discrete points on the balloon where marks had been made. Even when the film could be directly measured, this measurement method is limited to an accuracy of approximately 0.5%, with the values obtained representing an average over the entire range. This resolution limit can lead to small defects being missed.
Distributed strain gauges are inherently noisy and do not provide data from much of the balloon's surface. High noise levels in the signals make it difficult to detect the small changes that can be precursors of a larger failure. Averaging the data over time can improve sensitivity but it can delay detection of an impending failure. In addition, because strain gauges can only report changes in the local area around the strain gauge, localized failures between strain gauges can go undetected. Increasing the density of the strain gauges can improve the coverage, but more gauges and their connections also increase the weight of the system. This increase reduces the load capacity of the balloon, which means less instrumentation can be carried.
Using differential GPS (DGPS) is logistically complex and requires careful mounting of GPS receivers over the entire surface of the balloon. This type of system is less sensitive, and cannot detect point failures until they are large enough to deform the entire balloon shell. Current, state-of-the-art DGPS receivers have a relative accuracy measured in centimeters. Therefore, this approach would only be practical for monitoring large-scale balloon deflections. Like strain gauges, increasing receiver density can improve the coverage. However, such an increase in receiver number would increase the weight of the system and reduce the load capacity of the balloon. An effective system for measuring the strain on the balloon would preferably monitor the entire surface of the balloon with no need for an extensive network covering the surface of the balloon. Ideally, such a system would be able to detect impending failure of all sizes and from a variety of causes while adding a minimum of weight.
All the methods described above have fundamental limitations that severely limit the precision and accuracy capabilities of a balloon strain monitor. Therefore, there is a need for an improved method and system for measuring strain in birefringent materials, such as a plastic film forming a balloon. It would be desirable if the method and system were adaptable to measuring strain in birefringent materials in a variety of applications, including plastic film production processes and quality control. Ideally, such a method and system would provide spatially continuous monitoring of the birefringent material. Furthermore, it would be desirable if the method and system provided greater accuracy than any of the other existing technologies described above.
SUMMARY OF THE INVENTION
One embodiment of the present invention provides a method comprising analyzing multispectral images from a plurality of regions of birefringent material, such as a polymer film, using polarized light and a corresponding polar analyzer to identify differential strain in the birefringent material. For example, the birefringent material may be low-density polyethylene (LDPE), high-density polyethylene (HDPE), polypropylene, polyethylene terephthalate (PET), polyvinyl chloride (PVC), polyvinylidene chloride, polyester, nylon, or cellophane film or fiber. Optionally, the method includes generating a real-time quantitative strain map.
Another embodiment of the present invention provides a method of identifying strain in a birefringent material, comprising measuring light intensity (I) as a function of wavelength (λ) from a polarized light source through the surface area of the birefringent material and another polarizer, identifying the location of light intensity measurements that indicate the presence of optical retardation beyond a setpoint, and calculating a value representative of the extent of the optical retardation, such as a differential strain value. Alternatively, if the step of measuring is performed in the absence of any strain fluctuations, then the optical retardation may be attributed to deviations in thickness.
Yet another embodiment of the present invention provides a method of identifying strain, comprising detecting light intensity (I) as a function of wavelength (λ) from polarized light transmitted through birefringent material and another polarizer for each of a plurality of regions over a surface of birefringent material under differential strain (Δσ), calculating an optical retardation (δ) value for each of the plurality of regions as the best fit of the light intensity (I) as a function of wavelength (λ) data for that region using the transmittance relation T∝ Sin 2 [π(δ/λ)], wherein the transmittance (T) is a ratio of the light intensity detected under differential strain (I strain ) to light intensity through the birefringent material without strain (I relaxed ) or with unpolarized light or with linearly polarized light in which the polarization axis is aligned with the primary strain direction, as a function of wavelength (λ), and calculating a differential strain (Δσ) value for each of the plurality of regions by applying a correlation between optical retardation (δ) and differential strain (Δσ) to the optical retardation (δ) value calculated for that region. Optionally, the method may include identifying each of the plurality of regions by coordinates, and producing a map of the differential strain values arranged by the coordinates of the plurality of regions.
Preferably, the step of detecting light intensity (I) as a function of wavelength (λ) for each of a plurality of regions includes the steps of: (a) detecting light intensity (I) as a function of wavelength (λ) for each of a plurality of regions positioned along a first coordinate axis, and then (b) repeating step (a) for each of plurality of positions along a second coordinate axis. Optional further embodiments may include determining the polarization fraction of incoming light, using the polarization fraction to distinguish intensity variations resulting from changes in polarization fraction from intensity variations resulting from film strain, and factoring out intensity variations resulting from changes in polarization fraction. Still further, the method may include using a lens to control the size of each of the regions.
A further embodiment of the present invention provides a computer program product comprising a computer useable medium including a computer readable program, wherein the computer readable program when executed on a computer causes the computer to perform a method of the present invention.
A still further embodiment of the present invention provides a system for identifying strain in a birefringent material using a light source having an unknown polarization fraction, a variable polarization fraction or non-uniform distribution of polarization fraction. The system may comprise a hyperspectral polarimeter including a CCD camera, spectrograph, lens, and rotating polarizer for measuring light intensity as a function of wavelength, wherein the lens is disposed to focus light into the spectrograph, and wherein the rotatable polarizer is disposed in front of the lens or between the lens and the hyperspectral polarimeter, a computer processor in communication with the CCD camera for receiving the light intensity measurements; and a computer readable medium in communication with the processor and containing instructions, which when executed by the processor, cause the processor to determine an optical retardation value from the recorded intensity measurements, map this to a differential strain value, and create a map of strain in the birefringent material under analysis. In specific implementations, the system may optionally further include a solar tracking device, and a rotatable base for controllably rotating the hyperspectral polarimeter at approximately right angles to the sun.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic diagram of hyperspectral polarimeter (HP) being used to measure strain of birefringent film with a source of polarized light in accordance with the present invention.
FIG. 2 is a graph of relative intensity as a function of distance in the Y direction for the wavelengths between about 406 nm and 780 nm.
FIGS. 3A through 3P provide a series of graphs of data from a film under various known percent strain applied using a film tensioner, where the graphs are set out in pairs including a lower graph showing the average background intensity for a pixel and the spectrum obtained for that particular pixel and an upper graph showing the ratio of the two bottom plots and the fit used to determine the optical retardation.
FIGS. 4A through 4P provide a series of optical retardation maps for uniformly strained Ultra Long Duration Balloon (ULDB) film under applied strain varying from 0 to 15% to indicate the relative change in retardation for each plot. Oriented as shown, the stretching force on the film is applied vertically. The minimum, average, and maximum optical retardation values are indicated above each plot.
FIG. 5 is a graph illustrating the linear relationship between applied strain and average measured optical retardation.
FIG. 6 is a strain map of a high-strain area of a non-uniformly (25%-65%) strained polyethylene film.
FIGS. 7A through 7D provides a series of four optical retardation maps of one strained section of ULDB film obtained under various percentages of linearly polarized light intensity out of total light intensity passing through the film. For each set of data, consisting of the analysis for pixel (100, 90) and the complete retardation map, the light polarization fraction and mean retardation deviation is indicated. The deviation is calculated relative to the mean obtained from measurement of the film under 100% polarized light using only the crossed polarizer and background data. Note that a minimum fraction of polarized light is necessary to image the film, as indicated by the non-converging results obtained using 25% polarized light.
FIG. 8 is a perspective view of a HP centrally positioned at the base of a ULDB.
FIG. 9 provides front and back perspective views of a hyperspectral polarimeter arrangement suitable for use in a ULDB, in which the electronics will control the rotation of the base, the tilt of the spectrograph, and the rotation of the polarizer on the front of the unit through feedback loops created by optical encoders. Data is relayed from the spectrograph and CCD camera to the central computer in the base of the unit for computational analysis, balloon image reconstruction, and strain map generation.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a schematic diagram of hyperspectral polarimeter (HP) 10 being used to measure strain of birefringent film 12 with a source of polarized light 14 in accordance with the present invention. Unpolarized light 30 from the sun 32 is scattered from the atmosphere 34 and becomes linearly polarized when viewed from a 90° scattering angle. This polarization can also be used to analyze the strain in balloon films. The polarized light is optically retarded as it passes through the birefringent film. The optically retarded light 16 contains the strain information needed for analysis. After passing through a lens assembly 18 , the light traverses an analyzing polarizer 20 and is detected on a CCD imaging array 22 of the HP 10 . A spectrum 24 of light intensity as a function of wavelength is recorded for each pixel row 26 of the CCD array 22 . A curve-fit is automatically performed on the spectrum obtained from each pixel row to determine the magnitude of optical retardation, which is proportional to strain. Other rows of the CCD array 22 image other points along a vertical line on the balloon film 12 . Balloon rotation, for example, provides the scanning motion to image the entire balloon film. A complete strain map of the film is then produced by plotting the differential strain values determined for each point (such as point 28 ) on the film where the light came through.
Birefringent materials have two indices of refraction, a fast axis and a slow axis, which separate incident polarized light into two wavefronts traveling at two different velocities. Most polymer films become birefringent when they are stretched, such as low linear density polyethylene (LLDPE). The molecular orientations of the polymer chains are re-arranged as the polymer is pulled, producing an anisotropy in the film. This effect, known as stress birefringence or photoelasticity, allows a high degree of correlation between the strain in the polymer film and the alteration of the light polarization.
The Stress-Optic Law, or Brewster's Law, states that the relative change in the index of refraction is proportional to the difference in principal stresses applied to the material,
( n 1 −n 2 )= C B (σ 1 −σ 2 )
where n 1 and n 2 are the indices of refraction, σ 1 and σ 2 are the principle stresses, and C B is the stress-optical constant. Therefore, the difference in principal stresses is directly proportional to the birefringence, n 1 −n 2 =Δn. This birefringence causes a phase lag between the fast and slow light wavefronts in the material known as retardation, δ. This retardation can be directly determined from the birefringence of a material and its thickness, t, as δ=Δn·t. Combining these equations, the differential stress in the material can be determined;
σ=(σ 1 −σ 2 )=δ/( tC B ).
An identical relationship exists with strain for relevant materials within a range of deformation, albeit with a different constant of proportionality than C B . This strain relationship is used for the present invention.
To measure the retardation of the light, an analyzing polarizer is used to cause the intensity of transmitted light to vary with wavelength, producing an interference spectrum. The fractional transmittance of light as a function of wavelength can be described as
T(λ)∝ Sin 2 [π(δ/λ)].
Using this relation, the retardation in the birefringent material and, thus, the strain can be directly determined by curve-fitting the spectrum of light passing through the analyzing polarizer.
In polyethylene film, birefringence is directly proportional to strain and a similar relation to the stress-optic law applies. Although stress is proportional to strain for small deformations, hysteresis effects become apparent when the film is deformed beyond a point. However, the linear relationship between strain and birefringence remains constant for all deformations. Other polymer films such as polyester and nylon are photoelastic as well, although polyethylene is predominantly discussed here, since it is a common polymer film used in many applications, such as the shell construction of an Ultra Long Duration Balloon (UDLB).
Hyperspectral imaging itself is well-established and has been used for years in the field of astronomy. Hyperspectral imaging collects a continuous emission spectrum by dispersing the wavelength of light using gratings and measuring the wavelength intensities. A hyperspectral image is fully three dimensional. Every XY spatial pixel of the image has an arbitrarily large number of wavelengths allied with it. Ultimately, an intensity cube of data is collected for which two of the axis of the cube are spatial and one axis is wavelength. At each of the points in the 3D cube, there is an associated intensity value. Therefore, a plurality of the hyperspectral images provide four-dimensional information space. FIG. 2 illustrates a hyperspectral image for a single line scan in the Y direction. Specifically, FIG. 2 is a graph of relative intensity as a function of distance in the Y direction for the wavelengths between about 406 nm and 780 nm.
When the light source is not 100% polarized, such as would be the case on an actual ULDB flight, then the HP must be able to distinguish intensity variations due to changes in polarization fraction from intensity changes due to film strain. In order to achieve this, a technique has been devised which permits the determination of both polarization fraction and optical retardation from incoming light by rotating the polarizer in front of the HP. In 100% polarized light, the transmission coefficient through film with σ at 45° to the axes of the crossed polarizers it is located between is Sin 2 (πδ/λ)=A. Therefore, the measured light intensity through this arrangement would be T + =BA, where B is the background intensity through unstrained film between parallel polarizers. If the light is only fractionally polarized, as represented by the factor P, then the transmitted light intensity through strained film between crossed polarizers becomes T + =B(1−P)+BPA, Likewise, for 100% polarized light, the transmission coefficient for strained film through parallel polarizers is T = =B−BA. However, in fractionally polarized light, the transmission becomes T = =B−BPA. By linearly combining the two equations for transmission of fractionally polarized light, either the polarization fraction or the optical birefringence can be determined independently, as indicated below.
P =(2 B−T + −T = )/ B A= Sin 2 (πδ/λ)=( B−T = )/(2 B−T + −T = )
Therefore, by rotating the polarizer on the HP, the film strain can be determined even if the polarization fraction is unknown.
However, if you assume the light source is 100% polarized, then the simpler relationship for the transmission coefficient may be used. For the special case of 100% polarization, a background spectrum is obtained by imaging unstrained film between parallel polarizers. The data set for strained film between two crossed polarizers is read in next. In order to avoid an artificial offset in measured intensity, the “dark count” intensity measured with the HP shutter closed is subtracted from each spectrum and the background spectrum. This value is usually small in relation to the measured intensity (e.g. 70 counts out of a maximum of 4,096). The spectrum collected for each pixel is then divided by the background spectrum to produce the interference spectrum from which the optical retardation value is determined. (See graphs in FIGS. 3A through 3P ).
Once the interference plots for each pixel of an analysis map are obtained, they were fit to determine the value for optical retardation. Two approaches were explored for simple film strain at 45° to the axes of two crossed polarizers. The first used a one-parameter fit to δ in the function T=Sin 2 (πδ/λ), where T is the fractional intensity transmitted, δ is the optical retardation, and λ is the light wavelength.
To automatically generate a birefringence map from recorded data, an initial guess for the δ fitting parameter must be determined. Although “goodness of fit” may be visually apparent to a human user, the development of a separate optimization process to determine an appropriate starting parameter was necessary for automatic map generation. To determine this initial guess, five distributed points on the map were chosen as representative pixels. Fits were then performed on those points for a wide range of initial guesses for δ and the residuals of these fits were plotted as a function of δ. The δ value which produced a global minimum was then used as the initial guess parameter for all other pixels to produce a strain map. This technique produced accurate fits over a wide range of mapping conditions in slightly more than one minute. It may also be possible to obtain the strain information simply through polarizer rotation, without taking an initial background measurement.
A prototype hyperspectral imaging device was adapted for collecting the complete visible emission spectrum. The system was built around a standard Olympus IX70 epifluorescence microscope. For polarimetry measurements, a brightfield tungsten source was used to produce a broad, blackbody irradiance similar to solar light in the visual range. The side port of the microscope was optically coupled to a SpectraPro 556i spectrograph (Acton Research Corp., Acton, Mass.). A narrow entrance slit into the spectrograph allowed for only one line (˜0.1 μm using a 100× objective) of the image to be photographed.
The calculations described above for 100% polarized light were programmed using the MATLAB® platform by MathWorks. This software was then used to analyze the data sets produced from the hyperspectral imager. The software operated by first collecting a background image, consisting of unstrained film between two parallel polarizers, to generate an average reference spectrum. This reference was used to normalize the source intensity, absorption from the film and polarizer, detector efficiency profile, and other system components which may attenuate the signal non-uniformly as a function of wavelength.
EXAMPLE 1
Optical Retardation Maps
A series of tests were performed in which a polyethylene film sheet for a ULDB was uniaxially and incrementally strained a known and uniform amount using a film tensioning jig and the birefringence of the film was measured using the software methodology described above. The data from these tests is shown in FIGS. 3A-3P and FIGS. 4A-4P .
In the first set of plots shown in FIG. 3A , one pixel at the position of (100,100) near the center of the imaging region was arbitrarily chosen from the data cube for each strain value to indicate a representative recorded spectra and the automatic fit generated to determine optical retardation value. Most fits to the data appeared to be accurate and resulted in δ values that correlated well with expectation. Occasional fits deviated from the apparent best-fit, which added some noise to the resulting map of δ values. Often, this fitting deviation was the result of a localized intensity spike detected on the imaging CCD for a particular pixel, as was evident in the normalized spectra for the 8, 10, and 12% strain runs. Interference data for all relevant film strains was smooth and slowly-varying; therefore such localized spikes could be removed through post-processing by smoothing the data in software, thereby removing much of this noise.
The full δ maps for these strain values are shown in FIGS. 4A to 4P . Each map area imaged was approximately 11.1 mm×11.6 mm and each imaging pixel covered an area roughly 58 μm×58 μm. The plots are all shown using the same scale to indicate relative values as the strain is increased. Although this limits the δ resolution on any one map, it does permit simpler comparative evaluation. As can be seen from the series of images, there are some minor weak points in the particular piece of film imaged. These may be due to a crease, for example, that the film might have experienced before imaging. No visible defects were apparent in the film either before or after imaging, however. Aside from these localized effects, the applied strain was fairly uniformly distributed across the film.
EXAMPLE 2
Correlation between Optical Retardation and Strain
To determine the relation between physical strain and measured optical retardation, the average optical retardation fit value obtained over an entire map was plotted as a function of strain applied for the collection of all strain maps obtained from 0 to 15% strain, as shown in FIG. 5 . Vertical error bars shown are the standard deviation in δ measured on each map and the horizontal error bars are defined by the uncertainty in relative inter-clamp distance in the film tensioner. Note that an increase of 1% strain corresponds to only a 0.005″ distance increase between the tensioner clamps. This distance was difficult to control and measure to mil accuracy using the thumb wheels on the tensioner and an external caliper.
From this plot, the strain-optic ratio determined is [retardation (nm)/% strain]=9.2±0.3. The apparent linear offset in the data was determined to be due to a measurement artifact, rather than residual stress in the film. When film was clamped into the film tensioner, it would become slightly taut when the clamping screws were tightened. This imparted some initial strain to the film before the clamps were moved. Separate measurement of unclamped, unstrained film confirmed that the optical retardation of unstrained ULDB film is zero to within measurement uncertainty.
To confirm these results, additional measurements were then recorded on other pieces of ULDB film, taken from well-separated sections of one large ULDB film sample. These measurements demonstrated the measurement repeatability that the instrument and analysis method are capable of. By compiling the results from all three analyses, a weighted average of the strain-optical constant for ULDB film was obtained. The results for each of the three data sets were: 9.2±0.2 nm, 9.1±0.4 nm, and 8.8±0.4 nm. Therefore, the composite weighted average for all measurements was 9.1±0.2 nm, indicating an error within 3%. Based on these results, the ULDB film has been analyzed to produce real strain maps, as shown in the following section.
EXAMPLE 3
Film Strain Map
Calibrated strain maps, such as the one shown in FIG. 6 , demonstrate the capability of the hyperspectral polarimeter to precisely measure complex film strain, as might be found in a ULDB. The film represented in this image was a narrow strip which was non-uniformly deformed in order to evaluate the HP. In the orientation displayed, one clamp was just above the top of the image. The strain was distributed in a pattern typically seen during previous calibration attempts in which edge effects would dominate the strain distribution. There was high strain near the center of the film with sharp strain spikes near the clamping surface. This explains the behavior seen earlier where apparent strain values far exceeded the average distributed strain applied to a film. This data strongly indicates that the HP is a feasible technology for the ULDB platform.
EXAMPLE 4
Measurements Using Fractionally Polarized Light
The HP was used to take measurements with fractionally polarized light in order to determine the polarization fraction required for accurate measurements of strain. The intensities of the polarized source shown and the white light source could be varied independently to produce any polarization fraction from 0 to 1, although the uncertainty in the polarization fraction using this method was approximately ±10%. A polarized light source and a beam splitter were positioned so that polarization resulting from the beam splitter reflection was parallel to the polarization from the polarized light source. Therefore, one light source provided nearly 100% polarized light and the other provided almost 0% polarized light. This experimental configuration was used to collect the measurements below.
The two light sources used for these measurements had different spectral profiles and the method of mixing the two beams resulted in spatial non-uniformity across the film area measured. However, because the algebra used for analysis is insensitive to these types of variation, accurate strain maps were still obtained. The strain measurement results using 100%, 75%, 50%, and 25% polarized light are shown in FIG. 7A-7D , respectively.
The data shown were all recorded from the same piece of ULDB film in the same strain state. The only difference between measurements was the fraction of polarized light used during imaging. For each data set, the calculations to obtain the retardation interference pattern are shown graphically for pixel (100,90), as well as the complete retardation map obtained from the data set. Notice that in each of the lower plots for pixel (100,90), three curves are now shown, corresponding to the spectra obtained for the background, as well as strained film between crossed and parallel polarizers. To evaluate the data, the retardation maps were compared to the maps obtained in 100% polarized light, using the original analysis equation which took only the background and cross-polarized data as input. The deviation of the mean retardation value for each map from the mean retardation obtained through the original equation is indicated.
The signal-to-noise ratio (SNR) for the computed spectra decreases with decreasing polarization fraction. As a result, measurements in fractionally polarized light are more inaccurate than measurements taken with fully polarized light. If the fraction is low enough, the fitting equation will not converge accurately, as seen in the 25% polarized light data. Note from the pixel plots for the 25% polarization data, however, that it is not inherently the SNR but, rather, a crossing between the background, parallel, and crossed data sets which caused the computed interference spectrum to be ill-behaved. Recall that if 2B−T + −T = =0, then the computed interference spectrum (A) is undefined. If all three data sets could be taken nearly simultaneously, on the timescale of background fluctuations, this crossing behavior would not occur and accurate retardation maps could be obtained at a lower polarization fraction.
In one embodiment, the background measurement may be replaced with a hyperspectral measurement taken with the polarizers oriented at 45° to one another. This approach will also produce a background spectrum for each pixel which will be obtained at the time of measurement.
Implementation in a Balloon
It has been known for almost two centuries and explained for well over a century that sunlight which has been scattered off of the atmosphere is plane polarized. On the ground, the degree and orientation of polarization varies with the position of the sun and atmospheric conditions. At sea level, polarizations of 75% can be reached in the morning and evening, when sunlight is maximally scattered. As shown in FIG. 1 , light 30 from the sun 32 that has scattered from the atmosphere 34 becomes linearly polarized when viewed from a 90° scattering angle. This polarization can also be used to analyze the strain in balloon films.
As noted above, the polarization of skylight is at a maximum at an angle of 90° to the sun with a band extending on either side of this arc sufficiently polarized to be useful. As a result of this geometrical limitation it is not practical to image the entire surface of the balloon (ULDB) at one time. However, balloons typically rotate at a slow rate of less than 60°/min. at float altitude; as the balloon rotates its entire surface will pass between the centrally located imager and the arc of maximum polarization. The polarizer will be capable of rotating with respect to the imaging device. This rotation can be used to match the angle on the polarizer with the sun and hold it fixed to examine the balloon as each section passes over the arc of maximum polarization. This approach will work with almost any rotation rate. At higher rotation rates it may be more effective to target a specific section of film and capture a quick series of image slices when it passes through the optimal location. After an image slice is obtained, the HP is rotated slightly and another slice is collected.
In each of these approaches a series of images are collected, each of which has a portion of the balloon properly aligned for examination. The HP can zoom into one section of film for detailed analysis of a gore, or pan out to scan a broad area. An image of the entire balloon is obtained by stitching together the desirable portion of each of the multiple images obtained. The overall image can be analyzed for evidence of excessive strain, either over large areas or at small point defects. Images may be stored for comparison with later images to detect gradual changes, or transmitted to a ground station for further analysis, either automatically or manually.
A hyperspectral polarimeter flight unit 44 could be mounted at the base 40 of a ULDB 42 , as shown in FIG. 8 , and rotate based on feedback from a solar tracking device. The images obtained can then be analyzed on-board to determine the strain in the balloon wall and the results can be sent back to the ground via a radio transmitter.
The operation of the Hyperspectral Polarimeter 44 is consistent with the description of FIGS. 1 and 8 , where the scattered sunlight provides the initial polarization for analysis. As the scattered light passes through the balloon film 42 (See FIG. 8 ), birefringence resulting from strain in the film retards one optical axis with respect to the other. After crossing the balloon film, the light is collected by a lens assembly 46 attached to the inlet of the HP. By proper location of the detector, the lens 46 allows the HP to observe the entire interior of the balloon surface. The light then passes through a polarizer 48 that has its axis dynamically oriented relative to the polarization orientation of the incoming scattered light. This orientation is determined by noting the position of the sun, which is tracked as the brightest light source. On crossing this polarizer, the light spectrum is non-uniformly attenuated with respect to wavelength because of the optical retardation of one optical axis with respect to the other. If the balloon film is not strained, the incoming light would be unaltered and, hence, blocked by the polarizer. However, if the film is strained even a fraction of a percent, the light experiences a phase difference which varies depending on the light wavelength. As a result, an interference spectrum is produced which uniquely identifies the optical retardation of the light and, hence, the strain in the balloon film. By imaging the balloon with a hyperspectral analyzer, a full visual spectrum is recorded for each pixel of the compiled image. Each spectrum can then be fit with a function to determine the optical retardation produced by the balloon film and, thus, the strain in that film. By assigning a strain value to each pixel of the compiled image, a color-mapped image of the balloon can then be constructed to show the balloon film strain in real time. This data can then be sent to the ground control center via radio communication link either continuously or on command from ground control.
A hyperspectral polarimeter 44 is shown in FIG. 9 . Rotators 50 with optical-encoder feedback orient the unit in the direction of maximally polarized sunlight, perpendicular to the direction of the sun, and provide the tilt needed to scan the entire balloon surface, and rotate the polarizer 48 on the front of the unit to generate the measurements needed for strain analysis. The electronics to control this motion may be housed in the base 52 of the unit. The base may also house the central processor, which may be a laptop computer. The central computer will communicate with the spectrograph 54 and CCD camera 56 , such as through a USB 2.0 interface 58 , and will preferably analyze the hyperspectral data cubes collected to determine strain in the balloon film.
The measurements in the above Examples have demonstrated strain measurement in ULDB film with an accuracy of better than ±2% of the measured strain value and a full measurement range from 0% strain to well beyond the operating point of ULDBs. The HP can be installed on existing balloons without modification of balloon design except for a small mount near the base of the balloon. After a mission is complete, the HP can be recovered by parachute and reused for later missions.
The optical assembly is preferably capable of both a wide field of view of roughly 120°, to cover large swaths of balloon film for scanning operations, as well as a telephoto range of 10° for more detailed inspections of film areas. Although simple lens assemblies may be used, such as a Tessar, Double Gauss (Biotar), or Cooke (Taylor) triplet, a more advanced optical design might also be used.
Gratings can also be selected which are tailored for the wavelength range of interest, currently 500-650 nm, and which spread this range across the CCD imaging array. A 50 g/mm grating with a 600 nm blaze wavelength would be well suited to this task.
The CCD camera is the last stage of the light path and critical for accurate detection of the signal. The CCD should be fast, sensitive, and have the resolution required for imaging. In one embodiment, the camera may be oriented so that 1,340 pixels are used for spatial resolution (such as in the Y direction) and only 100 pixels are used for spectral resolution. Since the spectral profile is slowly varying, this resolution should be adequate for curve fits, whereas the spatial resolution will be more important for high-resolution film analysis.
The unit may then be actuated through mechanical rotators. Specifically, the HP is preferably capable of movement and orientation measurement through three degrees of rotational freedom to image all surfaces of a balloon. For example, the logic for the rotational control and position measurement system may utilize a spherical coordinate system. In practice, the HP is preferably located at the base of the balloon, but need not necessarily be positioned exactly in its center. Precise angular measurement and control are needed both to obtain adequate resolution as well as good registration accuracy when a strain map is reconstructed from individual images acquired as the balloon rotates. Additionally, the value of θ must be known precisely so that the images collected can be accurately matched to actual physical locations on the balloon. To achieve this requirement, a stepper motor and encoder may be used to rotate the base of the HP and measure its rotational position. A second degree of freedom corresponds to attitude measurement and control necessary to view various elevations or latitudes of the balloon. The HP may pivot forward and back on a horizontal axle, as driven by a linear actuator connecting the rear of the spectrograph mounting bracket to the base bracket. The linear actuator position may also be monitored by an embedded encoder to provide attitudinal feedback.
Lastly, the analyzing polarizer must be rotated about its axis in order to complete the actual measurement of balloon strain. The rotational accuracy requirement for this rotator is actually the least stringent of the three described here. A deviation from the intended rotation as large as 8°would affect the measured retardation value by less than 1%. However, as opposed to the other three, actuation is preferably rapid, because as many as three different orientations between 0° and 90° may be necessary.
The power supply for the HP in the ULDB may be a lithium ion battery pack. The power supply is used to power the spectrograph, the CCD Camera, the stepper motors, the encoders, and the computer processor. For example, a laptop computer may be used as the master system control.
The software is responsible for timing and synchronizing the motion of all actuators in the system, including the rotators, shutter, and grating turret, with the collection of raw data from the CCD array. Different operating modes may be accommodated depending on whether a zoomed-in image of a film section or a wide-ranging view of a major section of the balloon is being obtained. Coordination between the actuation elements and camera preferably has accurate registration between all the “slices” of the hyperspectral data cube.
All data signals for actuation can originate from the laptop software and be transmitted through digital TTL pulses to avoid timing delays. Mechanical actuation, both of rotators and the shutter, would be the most significant contributor to the time required for one image capture. Therefore, timing delays to allow mechanical elements to complete their motions must be integrated with the timing requirements for the camera, itself.
In one embodiment, each pixel is treated independently, including background determination, so that variations in background intensity can be directly accounted for on a pixel-by-pixel basis. Pixel analysis and polarization rotation positions are based on the generalized equation for optical retardation, T=B[(1−P)+P{Cos 2 φ−Sin [2(τ−φ]·Sin [2τ]·Sin 2 [π·δ/λ]}]. Here, T is the transmitted light intensity, B is the background light intensity as would be seen through parallel polarizers and unstrained film, P is the polarization fraction, φ is the angle between the sun polarization and the analyzing polarizer privileged directions, τ is the angle between the sun polarization and the film strain privileged directions, λ is the wavelength of light, and δ is the optical retardation. Again, δ is defined as τ·Δn, where τ is the effective film thickness and Δn is the film birefringence, equal to the product of the strain-optic constant and the difference in principal film strains. By working directly from the generalized equation, the computer program will be capable of determining the strain value even in the complex lighting environment found during a stratospheric flight.
The present invention may be implemented in stratospheric balloons used to perform high-altitude experiments economically. NASA engineers could use the data collected to better understand the behavior of ULDBs in flight, to predict their performance on future missions or modify future designs of the ULDB shell. The device can continuously monitor all film strain in a balloon, in-flight and in real time, from a single point of observation.
In a further embodiment, the proposed Hyperspectral Polarimeter system could be implemented without use of a spectrograph. In this implementation, the system would be identical in all respects but, after crossing the polarizer, light would be directly imaged on a CCD array, instead of first passing through a spectrometer. Instead of taking a full spectrum of the incident light, the intensity would be recorded at the wavelengths corresponding to red, green, and blue light. Although this recording method would provide some information about the light spectrum, it would also be highly affected by signal noise. The precision and accuracy would be considerably reduced, compared to the capabilities of the hyperspectral polarimeter. Additionally, complex interference spectra could not be accurately reproduced, since only three points on the spectral curve would be represented.
Embodiments Utilizing Fiber Optics
In a further embodiment, the invention may utilize an array of fiber optic cables to transmit the light which has passed through the birefringent material into the spectrograph. At the entrance to the spectrograph, the fiber optic cables that made up the optical array, which collectively form a field of view that is square or other shape, are rearranged into a line to match with the entrance slit of the spectrograph. The light from each individual fiber is diffracted off a grating and images on a specific row of a CCD camera. This measurement configuration enables simultaneous acquisition of spectral data from each of the pixels that make up the instrument's field of view. Accordingly, there is no scanning or panning necessary which would blur rapid events. Once the spectra from each pixel in the fiber array have been read by the spectrograph, they can each be curve fit, based on the known transmission function for the material. In a reduced form, the transmitted light intensity is T λ =B·Sin 2 [π·δ/λ], where B is the background light intensity, λ is the wavelength of light, and δ is the optical retardation of the light, equal to the birefringence of the material times its thickness, δ=Δn−τ.
In a specific embodiment, the optical fiber array may form a square that is 32 pixels (fibers) wide and 32 pixels (fibers) long, so that 1,024 spectra will stream to on-board memory for later analysis. Using high speed electronics this amount of spectral data might be acquired every 0.5 milliseconds. The array could image a large area or the light from a smaller area can be focused into the array for higher resolution of the data.
The terms “comprising,” “including,” and “having,” as used in the claims and specification herein, shall be considered as indicating an open group that may include other elements not specified. The term “consisting essentially of,” as used in the claims and specification herein, shall be considered as indicating a partially open group that may include other elements not specified, so long as those other elements do not materially alter the basic and novel characteristics of the claimed invention. The terms “a,” “an,” and the singular forms of words shall be taken to include the plural form of the same words, such that the terms mean that one or more of something is provided. For example, the phrase “a solution comprising a hydrocarbon-containing compound” should be read to describe a solution having one or more hydrocarbon-containing compound. The term “one” or “single” shall be used to indicate that one and only one of something is intended. Similarly, other specific integer values, such as “two,” are used when a specific number of things is intended. The terms “preferably,” “preferred,” “prefer,” “optionally,” “may,” and similar terms are used to indicate that an item, condition or step being referred to is an optional (not required) feature of the invention.
It should be understood from the foregoing description that various modifications and changes may be made in the preferred embodiments of the present invention without departing from its true spirit. It is intended that this foregoing description is for purposes of illustration only and should not be construed in a limiting sense. Only the language of the following claims should limit the scope of this invention. | A method, computer program product and system for analyzing multispectral images from a plurality of regions of birefringent material, such as a polymer film, using polarized light and a corresponding polar analyzer to identify differential strain in the birefringent material. For example, the birefringement material may be low-density polyethylene (LDPE), high-density polyethylene (HDPE), polypropylene, polyethylene terephthalate (PET), polyvinyl chloride (PVC), polyvinylidene chloride, polyester, nylon, or cellophane film. Optionally, the method includes generating a real-time quantitative strain map. | 6 |
FIELD
This invention relates to rotary vane compressors and more particularly to an improved compressor which exhibits low sound emission due to a combination of improved elements.
BACKGROUND
Rotary vane compressors are used in a variety of applications. One such compressor includes a rotor having vane receiving slots with a vane in each slot. The rotor is rotated, in an eccentric manner, in a cavity within a body to produce compressed gas. One major application is in home sewage treatment. There the rotary vane compressor is used to pump air into home sewage treatment tanks to provide bacteria growth, which in turn, will break down the effluent in the tank. The compressor is typically located outside, next to the house and operates continuously.
A typical rotary vane compressor is sold by Gast Manufacturing, Inc. of Benton Harbor, Mich., 49023-0097 as its “23 Series”. These compressors usually include the following components: (1) a motor in a vented housing having a bearing mounted drive shaft; (2) a vented back plate or closure for the motor housing; (3) a rear plate mounted to the housing and though which the shaft extends; (4) an inlet ring between the motor housing and rear plate; (5) a rotor with vanes mounted to the drive shaft, and positioned within a body; (6) a vented shroud surrounding the body which abuts the motor housing; (6) a front plate that bears against the body and rotor; and (7) a muffler box positioned against the front plate and through which air enters and exits the compressor.
The muffler box, front plate, body, rear plate and motor housing are secured together. The major moving parts are the motor, drive shaft, bearings and rotor with vanes all of which produce sound. However, vibration of the non-moving parts is also important. The compressor emits sound during operation, which due to its 24-hour operation can become irritating over time.
It is an object of this invention to reduce the sound of the compressor when it operates.
This and other objects of the invention will become apparent from the following description and independent claims.
SUMMARY
The compressor of this invention is quieter in operation and exhibits reduced sound emission. The compressor operates at sound levels of less than about 50 dBA (decibels) at one meter. This low sound level has been achieved by various improvements taken in combination. These include improvements relate to the motor, a shorter non-vented motor housing, a non-vented back plate for the motor housing, improved bearings for the drive shaft, and a change in the rotor carrying body such as an increased mass, a solid or non-vented shroud made of a laminated material that surrounds the body, modifications in the vane carrying rotor and optionally an improved muffler box made out of a cast iron, zinc or magnesium casting.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is an isometric view of a sound-reduced rotary vane compressor;
FIG. 2 is a back view of the compressor of FIG. 1 ;
FIG. 3 is an exploded isometric view of components of the compressor of FIG. 1 ;
FIG. 4 is a top or elevational and exploded view of components shown in FIG. 3 ;
FIG. 5 is a front view of an improved inlet ring used in the compressor of FIG. 1 ;
FIG. 6 is a perspective view of the body used in the compressor of FIG. 1 ;
FIG. 7 is a top view of the body of FIG. 6 ;
FIG. 8 is a front view of the body of FIG. 6 ;
FIG. 9 is a front view of the vane-carrying rotor used in the compressor of FIG. 1 ;
FIG. 10 is a side view of the rotor used in the compressor of FIG. 1 ;
FIG. 11 is a perspective view of a non-vented cylindrical shroud used in the compressor of FIG. 1 ;
FIG. 12 is a sectional view of the shroud taken along line 12 — 12 of FIG. 11 and showing the laminated construction of the shroud.
DESCRIPTION
The compressor 10 is shown in FIG. 1 . Externally the compressor has a solid, non-vented motor housing 12 , a non-vented back 13 , a rear plate 14 , a solid non-vented shroud 16 , a front plate 18 and a muffler box 20 . The components are bolted together so as to form a unit. Two ports 22 and 24 are provided in the muffler box for the entry of air and exit of compressed air. Muffler constructions 26 and 28 are provided for use in the muffler box. The rear or back 13 of the compressor is shown in FIG. 2 and includes a solid non-vented plate.
Referring now to FIG. 3 , an exploded view of the compressor is shown and the internal mechanism can be seen. In the housing there is positioned an electric motor which can be generally characterized as a one-sixth horsepower motor, having a four pole stator and a six pole rotor. The housing 12 has a maximum length of about 5.22 inches so as to reduce the vibrations. The motor's rotor drives a drive shaft 30 which is mounted on a plurality of deep groove ball bearings 32 .
An inlet ring 34 is positioned against the motor housing 12 . There is provided the rear plate 14 which includes a centrally positioned bolting and bearing support section 38 which is held in position by a plurality of webs such as 40 . It is seen that the drive shaft 30 is also supported by a second set of bearings 42 which is secured to the section 38 . The rear plate 14 is secured to the motor housing with the inlet ring 34 positioned therebetween like a gasket. Bolts such as 44 from the motor housing are secured to the periphery of the rear plate 14 . The shroud 16 is non-vented and made of a laminated material and fits against the rear plate 14 .
The body 36 defines a rotor cavity 46 therein, fits within the shroud 16 , has a radius of at least about 2.62 inches, a minimum weight of about 4.63 pounds, and is made of a gray iron casting, more specifically SAE J4321 G2500. A rotor and vane assembly 48 is positioned within the cavity 46 . The drive shaft 30 extends to and engages the rotor and rotates the assembly 48 . The assembly 48 includes the rotor 50 and four vane receiving slots such as 52 within each of which there is a positioned a vane 54 . It will be appreciated that the motor rotates the drive shaft which, in turn, rotates the assembly 48 for compressing incoming air and expelling compressed air. When the rotor is rotated, each vane can slide within a rotor slot and can engage the cavity wall or body 36 . The front plate 18 engages the front face of the body 36 and is divided into two chambers or sections 58 and 60 by the by a central rib 62 and peripheral edge 64 . The muffler box 20 which is preferably made from a gray iron, but can be made from die cast aluminum, is secured against the front end plate. The muffler box defines the exit and inlet ports 22 and 24 and each communicates with a chamber 58 or 60 . The muffler box is deep enough to receive the muffler elements 26 and 28 .
Elements or components of the compressor are also seen in FIG. 4 and include the motor housing 12 , the drive shaft 30 , the inlet ring 34 , the rear plate 14 , the shroud 16 , the rotor assembly 48 , the body 36 , the front plate 18 and muffler box 20 .
Inlet Ring
The inlet ring 34 is seen in FIG. 5 . The ring 34 has a small wall thickness 66 [i.e., the difference between the outside diameter (OD) and inside diameter (ID)] of about 1.25 inches and is made of 20 gage cold rolled steel. The ring is positioned between the motor housing 12 and the rear plate 14 . The ring is crushable and acts like a gasket to seal against both the housing and plate. The ring OD is fixed by the compressor size and the ID is increased as much as possible so as to reduce vibration and maintain sealing.
The Body
The body 36 is shown in FIGS. 6 , 7 and 8 . The body 36 has a positioning groove 62 located at the top thereof, has an increased mass or, a weight of about 4.63 pounds, as well as an increased outer radius 68 of about 2.62 inches. The body 36 is fabricated from a first sound dampening material, which in a preferred embodiment,is gray iron, as specified hereinbefore, which exhibits good sound-dampening characteristics. In addition, the size, weight and mass of the body is maximized so as to maximize sound dampening. The outside diameter is increased, but is limited by the size of the compressor. The inside diameter or cavity is maintained for cooperation with the rotor assembly.
Rotor
The rotor body 50 which has vane-carrying slots such as 52 is shown in FIGS. 3 and 9 . Each of the slots carries a vane, extends into the rotor body, is at right angles to an adjacent vane slot and forms a chord-like construction which extends from the circumference or periphery of the rotor into the rotor body as shown. The positioning of the slot relative to the center and relative to the other slots is important in reducing the sound of operation. The angular relation between the centerline of a vane receiving slot and a line passing through the rotor center and the center of the vane slot opening at the periphery of the rotor is about 24°. The angular relation can vary between 23° and 25°. This angular relationship is important as it permits vane movement in the slot and reduces vane bounce during rotation. The mass or weight of each vane is important to maximize radial force. The weight of the vane herein is about 6.75 grams. The combination of vane mass and angular relation also reduces vane bounce and noise.
The Shroud
FIGS. 10 , 11 and 12 show the shroud 16 . The shroud 16 is a cylindrical member which fits about the body 18 and engages the rear plate 14 and the front plate 56 . The shroud is a solid non-vented member which can be made of a laminated structure seen in FIG. 12 . The laminated structure may include at least one of an outer metal layer 70 and an inner metal layer 72 . Also, the laminated structure includes and an intermediate viscous layer 74 made from a second sound dampening material.The solid or non-vented structure and the laminated structure contributes to the dampening or sound reduction. The inner and outer layers are 24 to 26 gauge Galvaneal steel (Galvaneal steel is electro-galvanized steel which is made for painting) and the sound dampening material is a viscous material such as Acrylic pressure sensitive adhesive. The laminate can be purchased from Roush Anatrol Main Office, 11953 Market Street, Livonia, Mich. 48100, under the trade name Anatrol 980.
Bearings
The bearings such as 32 and 42 are referred to as deep groove ball bearings (See NSK catalog, Rolling Bearings, Cat. No. A 140b, 19933-10 Printed in Japan, Copyright NSK Ltd. 1989) are sealed and utilize a grease or lubricant to dampen sound. This grease or lubricant is a polyurea grease (available as POLYREX EM, from Exxon Mobile Corporation, 3225 Gallows Road, Fairfax, Va. 22037. The combination of the deep groove bearing and grease reduce the sound of operation.
Motor and Housing
The motor itself is one-sixth horse power, 6-pole rotor and 4-pole stator type. The motor housing is less than about 5.22 inches in length and is solid or non-vented. Sound emanating from the motor during operation has been minimized.
The back or closure 13 for the motor housing 12 is a solid non-vented member which is secured to the housing. The fact that the back is solid and non-vented minimizes sound emanating from the rear of the compressor.
Summary
The combination of above-identified factors reduces the sound emitted from the compressor during operation to about 50 dB at 1 meter. Those factors include the solid non-vented motor housing 12 , the solid non-vented housing back 13 , the 6-pole rotor 4-pole stator motor, the deep groove bearings 32 and 42 and lubricant, the rotor-vane angular relationship and vane weight or mass, the increased body size and mass 18 and the non-vented solid or laminated shroud 16 . In addition, the muffler 20 can be made of various materials so as to enhance the sound deadening property.
It will be appreciated that numerous changes and modifications can be made to the embodiments detailed above. | A rotary vane compressor having features for reducing sound emitted from the compressor during operation. The sound reduction features include and relate to specific components of the compressor. Specifically the features relate to (1) the compressor motor; (2) a non-vented motor housing and back or closure; (3) the inlet ring; (4) the bearing system; (5) the rotor and vane positioning and vane weight or mass; (6) the mass of the body within which the rotor and vane rotate; and (7) a shroud which surrounds the body which is solid and non-vented solid and may be formed of a laminated material having a sound dampening core layer. | 5 |
TECHNICAL FIELD
[0001] The present invention generally relates to a cooled vane component in a gas turbine engine. More specifically, the gas turbine vane has an improved cooling flow design and lower operating stresses.
BACKGROUND OF THE INVENTION
[0002] Gas turbine engines operate to produce mechanical work or thrust. Specifically, land-based gas turbine engines typically have a generator coupled thereto for the purposes of generating electricity. A gas turbine engine comprises an inlet that directs air to a compressor section, which has stages of rotating compressor blades. As the air passes through the compressor, the pressure of the air increases. The compressed air is then directed into one or more combustors where fuel is injected into the compressed air and the mixture is ignited. The hot combustion gases are then directed from the combustion section to a turbine section by a transition duct. The hot combustion gases cause the stages of the turbine to rotate, which in turn, causes the compressor to rotate.
[0003] The air and hot combustion gases are directed through a turbine section by turbine blades and vanes. These blades and vanes are subject to extremely high operating temperatures, often times upwards of 2800 deg. F. These temperatures often exceed the material capability from which the blades and vanes are made. Extreme temps also cause thermal growth in the component, which if not permitted, causes thermal stresses and can lead to cracking. In order to lower the effective operating temperature, the blades and vanes are cooled, often with air or steam. However, the cooling must occur in an effective way so as to use the cooling fluid efficiently.
SUMMARY
[0004] In accordance with the present invention, there is provided a novel configuration for a gas turbine vane assembly that provides effective cooling to gas-path surfaces while permitting movement of the platform. The vane assembly includes a plurality of airfoil cooling tubes and directed cooling to a vane platform.
[0005] In an embodiment of the present invention, a gas turbine vane assembly comprises an outer diameter pan coupled to an outer diameter platform, a hollow airfoil extending radially inward from the outer diameter platform, and an inner diameter platform connected to the hollow airfoil opposite the outer diameter platform such that the platforms are generally parallel to each other. The outer diameter platform has a trailing edge face spaced an axial distance from a leading edge face and includes a plurality of openings capable of receiving a plurality of cooling tubes and a tube collar associated with each of the plurality of openings. The plurality of cooling tubes extend radially inward from the outer diameter platform such that the tube collars are connected to each of the plurality of cooling tubes and the corresponding opening at the outer diameter platform. The plurality of cooling tubes extend through passages in the airfoil. The inner diameter platform includes a trailing edge face, a leading edge face, a plurality of corresponding openings for receiving the plurality of cooling tubes. A cover is fixed to each of the plurality of cooling tubes proximate the inner diameter platform and a forward pan is coupled to a forward end of the inner diameter platform while a meterplate is fixed to the inner diameter platform adjacent to the forward pan and is in fluid communication with an aft pan that is connected to an aft end of the inner diameter platform. The meterplate has a plurality of holes located therein capable of restricting a cooling fluid flow to a desired pressure and mass flow for a region of the holes positioned in the inner diameter platform and in fluid communication with the aft cavity. An aft cover is fixed to the aft end of the inner diameter platform to form an aft cavity. The inner diameter platform also includes a plurality of holes that receive a cooling fluid from the aft pan. An undercut is positioned in the inner diameter platform for providing increased flexibility to the inner diameter platform.
[0006] In an alternate embodiment, a flow restriction device capable of controlling a cooling fluid to an aft portion of an inner diameter platform of a gas turbine vane comprises an aft cover fixed to the inner diameter platform forming an aft cavity, a meterplate with a plurality of feed holes fixed to the inner diameter platform between a forward pan and the aft cover, a plurality of file cooling holes located in the inner diameter platform and in fluid communication with the aft cavity, and wherein the cooling fluid is capable of passing through the feed holes of the meterplate, into the aft cavity, and through the plurality of film cooling holes.
[0007] In yet another embodiment, an inner diameter platform of a gas turbine vane capable of increased thermal deflection comprise a gas path surface separated from a cold surface by a platform thickness, a forward pan, and an aft cover fixed to the cold surface. The platform thickness having an undercut extending between the gas path surface and cool surface, such that the undercut reduces stiffness of the inner diameter platform adjacent to the aft cover.
[0008] Additional advantages and features of the present invention will be set forth in part in a description which follows, and in part will become apparent to those skilled in the art upon examination of the following, or may be learned from practice of the invention. The instant invention will now be described with particular reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0009] The present invention is described in detail below with reference to the attached drawing figures, wherein:
[0010] FIG. 1 is an exploded view of the a gas turbine vane in accordance with an embodiment of the present invention.
[0011] FIG. 2A is a perspective view of an embodiment of the present invention including a plurality tube collars.
[0012] FIG. 2B is an alternate perspective view of an embodiment of the present invention that includes an outer diameter pan over the outer diameter platform.
[0013] FIG. 3 is a cross section view looking at the gas path surface of the outer diameter platform in accordance with an embodiment of the present invention.
[0014] FIG. 4 is a perspective view of a trailing edge cooling tube used in an embodiment of the present invention.
[0015] FIG. 5 is a perspective view of a mid-body cooling tube used in an embodiment of the present invention.
[0016] FIG. 6 is a cross section view looking at the gas path surface of the inner diameter platform in accordance with an embodiment of the present invention.
[0017] FIG. 7 is a perspective view looking at the cool surface of the inner diameter platform without the inner diameter pan in accordance with an embodiment of the present invention.
[0018] FIG. 8A is a detailed perspective view of a portion of FIG. 7 in accordance with an embodiment of the present invention.
[0019] FIG. 8B is a detailed perspective view similar to that of FIG. 8A but with the aft pan in place in accordance with an embodiment of the present invention.
[0020] FIG. 9 is a perspective view from the cool surface of the inner diameter platform with the inner diameter pan connected to the aft end of the inner diameter platform in accordance with an embodiment of the present invention.
[0021] FIG. 10 is a detailed perspective view of an inner diameter platform in accordance with an alternate embodiment of the present invention.
[0022] FIG. 11 is a cross section view of the airfoil of the vane assembly in accordance with an embodiment of the present invention.
DETAILED DESCRIPTION
[0023] The subject matter of the present invention is described with specificity herein to meet statutory requirements. However, the description itself is not intended to limit the scope of this patent. Rather, the inventors have contemplated that the claimed subject matter might also be embodied in other ways, to include different components, combinations of components, steps, or combinations of steps similar to the ones described in this document, in conjunction with other present or future technologies.
[0024] Referring to FIG. 1 , an exploded view of the gas turbine vane 100 , is depicted. An outer diameter pan 102 is affixed to the outer diameter platform 112 and has a plurality of holes 103 . Acceptable means for fixing the outer diameter pan 102 to the outer diameter platform 112 includes welding or brazing. The outer diameter platform 112 has a cool surface 111 and a gas path surface 113 . A plurality of cooling tubes 104 , 106 , and 108 extend from the outer diameter platform 112 . Specifically, the leading edge cooling tube 104 , mid-body cooling tube 106 , and the trailing edge cooling tube 108 are placed through openings in the outer diameter platform 112 , extending through the hollow airfoil 114 and reaching respective openings in the inner diameter platform 116 . Each opening in the outer diameter platform 112 has a respective tube collar 110 that is affixed to each of the cooling tubes 104 , 106 , and 108 and the corresponding opening. The outer diameter platform 112 has a leading edge face 112 A and a trailing edge face 112 B.
[0025] The cooling tubes 104 , 106 , 108 are capped at the inner diameter platform 116 . This embodiment illustrates three cooling tubes but the quantity of cooling tubes is not limited to exclusively three tubes. Covers 120 are affixed to the openings of the tubes to prevent cooling fluid from flowing from the airfoil 114 into the inner diameter platform 116 . The inner diameter platform 116 has a gas path surface 115 and a cool surface 117 that are separated by a platform thickness. The inner diameter platform 116 has a leading edge face 116 A and a trailing edge face 116 B.
[0026] An undercut 118 is located along within the inner platform thickness of the inner diameter platform 116 . The undercut 118 extends between the gas path surface 115 and the cool surface 117 . The undercut 118 can also be located adjacent to a joint between the aft cover 126 and the inner diameter platform 116 . The undercut 118 provides for increased flexibility of the inner diameter platform 116 , which helps to decrease the stress in the joint between the aft cover 126 and the inner platform 116 . Extending along the inner platform is a rail 119 that provides structural rigidity to the inner diameter platform 116 .
[0027] A meterplate 122 is affixed to the inner diameter platform 106 adjacent to a forward pan 124 . The meterplate 122 is oriented generally perpendicular to the inner diameter platform 116 so as to close an opening in the aft cavity while permitting a flow of the cooling fluid to enter the aft cavity generally parallel to the inner diameter platform 116 . The meterplate 122 restricts a supply of fluid flow to a desired pressure and mass flow for a region of film holes between a forward plenum and an aft plenum formed adjacent to the inner diameter platform 116 .
[0028] A forward pan 124 is affixed to the forward end of the inner diameter platform 116 and has a plurality of cooling holes 148 . An aft pan 126 is affixed to the aft end of the inner diameter platform 116 and does not have any cooling holes located therein. The aft pan 126 forms an aft cavity and has a generally flat portion and three sidewalls. Acceptable means for fixing the aft pan and the forward pan includes welding or brazing. In the gas turbine vane assembly 100 , the outer diameter platform 112 , the airfoil 114 , and the inner diameter platform 116 can be one single part, a welded assembly of parts, or any combination in between.
[0029] Referring to FIG. 2A , a view of the cool surface 111 of the outer diameter platform 112 without the outer diameter pan 102 , is depicted. The outer diameter platform has a trailing edge face and a leading edge face, where the outer diameter platform trailing edge face is spaced an axial distance from the outer diameter platform leading edge face. The openings for each of the cooling tubes is shown and fixed to the openings are the tube collars 110 for the corresponding cooling tubes. Referring to FIG. 2B , a view of the cool surface 111 of the outer diameter platform 112 with the outer diameter pan 102 , is depicted. The figure illustrates how the outer diameter pan 102 is affixed to the outer diameter platform 112 . The plurality of cooling holes 103 located on the outer diameter pan 102 are oriented at a surface angle relative to the outer diameter platform 112 .
[0030] Referring to FIG. 3 , a cross section view looking at the gas path surface 113 of the outer diameter platform 112 , is depicted. A plurality of cooling holes 121 are illustrated. Also, there are the openings for each of the cooling tubes. The cooling holes 103 located on the outer diameter pan 102 supply cooling fluid to pass through the cooling holes 121 to cool the gas path 113 surface of the outer diameter platform 112 .
[0031] Referring to FIG. 4 , an illustration of a trailing edge cooling tube 108 , is depicted. The trailing edge (TE) cooling tube 108 has an opening 128 , an opposing end 130 and a plurality of cooling holes 132 . The opening 128 receives cooling fluid from the outer diameter platform 102 with the cooling fluid passing through the tube 108 . The end 130 of the TE cooling tube 108 is closed by a cover 120 which prevents the cooling fluid from flowing into the inner diameter platform 116 . Since the cooling fluid is trapped in the body of the TE cooling tube 108 , the cooling fluid is forced out through the plurality of holes 132 . The cooling fluid exits the cooling tube and is directed towards an inner wall of the airfoil 114 and thus, cooling the airfoil 114 . The cooling fluid can be air or stream or a comparable cooling fluid. The TE cooling tube 108 also has raised surfaces 134 along the tube 108 . These raised surfaces 134 touch the inside of the airfoil and helps to hold the tube in place.
[0032] Referring to FIG. 5 , an illustration of a mid-body cooling tube 106 , is depicted. The mid-body cooling tube 106 has an opening 136 , and an opposing end 138 , and a plurality of cooling holes 140 . Similar to the TE cooling tube 108 , the mid-body cooling tube 106 directs cooling fluid from the outer diameter platform 112 and into the opening 136 of the mid-body cooling tube 106 . The cooling fluid is trapped in the body of the tube 106 because the end 138 is closed off with a cover 120 affixed at the inner diameter platform 116 . This forces the cooling fluid to pass through the plurality of holes 140 and onto the inner wall of the airfoil 114 .
[0033] Referring to FIG. 6 , a cross section view looking at the gas path surface 115 of the inner diameter platform 116 , is depicted. This view is from the gas path side 115 of the turbine vane. The inner diameter platform 116 can have a plurality of cooling holes 142 for directing a supply of cooling fluid along the gas path surface 115 of the inner diameter platform 116 . The cooling holes 142 could be oriented at a surface angle relative to the inner diameter platform 116 . This allows for improved cooling of the gas path surface 115 of the inner diameter platform 116 .
[0034] Referring to FIG. 7 , a view looking at the cool surface 117 of the inner diameter platform 116 without the inner diameter pan 124 , is depicted. The covers 120 are affixed to the cooling tubes to prevent cooling fluid from flowing into the cooling tubes 104 , 106 , and 108 from the inner diameter platform 116 . The meterplate 122 is shown affixed to an inner rail 119 of the inner diameter platform 116 . The undercut 118 in the inner diameter platform 116 is also visible. The exact size and shape of the undercut 118 can vary depending on the vane configuration. However, the shape of the undercut 118 is designed to reduce any stress concentrations and to decrease stiffness in the inner diameter platform 116 . In one embodiment, as shown in FIG. 7 , the undercut 118 has a general U-shape cross section.
[0035] Referring to FIG. 8A , a close up view of the sidewall portion of the inner diameter platform 116 of FIG. 7 , is depicted. FIG. 8A illustrates an example of a sheet metal seal slot 146 along one of the side walls of the inner diameter platform 116 and outer diameter platform 112 . There are a plurality of cooling holes 144 extending through the inner diameter platform 116 . Cooling fluid is provided through the cooling holes 148 of the inner diameter pan 124 . The cooling fluid is passed through the plurality of holes 144 on the cool side of the inner diameter platform 116 . The cooling fluid then passes through the cooling holes 142 on the gas path surface 115 of the inner diameter platform 116 to help cool the gas path surface 115 of the turbine vane. The illustrated slot 146 is an example of the orientation and position of a sealing slot. A sheet metal seal fits into the slot 146 .
[0036] Referring to FIG. 8B , a similar view to FIG. 8A , but with the aft pan 126 included. The aft pan 126 receives the cooling fluid and directs the cooling fluid into the inner diameter platform 116 and through the plurality of cooling holes 144 located along the inner diameter gas path surface 115 .
[0037] Referring to FIG. 9 , a view looking at the cool surface 117 of the inner diameter platform 116 with the inner diameter pan 124 , is depicted. The inner diameter pan 124 can have a plurality of cooling holes 148 for receiving a supply of cooling fluid and directing the cooling fluid to holes 142 in the inner diameter platform. In this view of the inner diameter platform 116 , the undercut 118 , the meterplate 122 and the cooling tube covers 120 are visible.
[0038] Referring to FIG. 10 , a close up, cutaway section of the cool surface 117 of the inner diameter platform 116 , is depicted. In this view of the inner diameter platform 116 , the undercut 118 and the aft pan 126 are visible.
[0039] Referring to FIG. 11 , a view from the top of the cross section of the airfoil 114 , is depicted. The figure illustrates the three hollow cavities for holding the three cooling tubes 104 , 106 , and 108 . However, the invention is not limited to three cavities within the airfoil and can be more or less than three.
[0040] The present invention has been described in relation to particular embodiments, which are intended in all respects to be illustrative rather than restrictive. Alternative embodiments will become apparent to those of ordinary skill in the art to which the present invention pertains without departing from its scope.
[0041] From the foregoing, it will be seen that this invention is one well adapted to attain all the ends and objects set forth above, together with other advantages which are obvious and inherent to the system and method. It will be understood that certain features and sub-combinations are of utility and may be employed without reference to other features and sub-combinations. This is contemplated by and within the scope of the claims. | A gas turbine vane to improve vane performance by addressing known failure mechanisms. A cooling circuit to the trailing edge of a vane airfoil is fed from the outer diameter platform, which prevents failure due to an oxidized and eroded airfoil trailing edge. The gas turbine includes an outer diameter platform, a hollow airfoil and an inner diameter platform with a plurality of cooling tubes extending radially through the airfoil. The cooling tubes are open at the outer diameter end and closed with covers at the inner diameter end. The inner diameter platform is also cooled and includes a meterplate for a portion of the cooling passageway and includes an undercut to improve thermal deflections of the inner diameter platform. | 5 |
TECHNICAL FIELD
Embodiments of the invention relate to systems for borehole cleaning that allow removal of materials in a borehole preventing flow. In particular, embodiments of the invention relate to system for use in wells such as oil and gas wells.
BACKGROUND OF THE INVENTION
As oil and gas are extracted from producing wells, sand and heavy oils that have flowed through the perforations accumulate. These are too heavy to flow to the surface along with the usual fluids produced by the well at normal production rates, and tend to accumulate in low-lying areas as shown in FIGS. 1 and 2 . Additionally, drilling muds used during the drilling process are generally heavier than the reservoir fluid, and tend to also segregate to low-lying areas of the well. Finally, proppant used during reservoir fracturing operations is not always completely removed. The accumulation problem in particularly severe where the trajectory of the well 10 is at or close to horizontal in the producing reservoir 12 and sumps 14 are present. Deposits 16 in these regions reduce the effective cross-section of the well 10 with a corresponding decrease in flow area 18 and therefore increase the pressure drop of the production fluids. In order to maintain or increase the production of such a well, it is necessary to remove this fill. Conventional methods of fill removal (or cleanout) involve high-pressure jetting through coiled tubing (CT) to mobilize the fill around the cleaning tool and sweep it to the surface by slowly pulling the CT up, the flow of jetting fluid and production fluid carrying the loosened fill to the surface. This high pressure mobilization jetting does increase the Bottom Hole Pressure (BHP) of the reservoir though, so it is only applicable to wells in formations that can sustain a full hydrostatic column (or foam column, in the case of foam clean-outs) and the increased pressure due to jetting. An example of one such technique is the PowerCLEAN service offered by Schlumberger.
In most well cleanout applications, the reservoir pressure is high enough, and the rock permeability low enough, to allow increase of pressure in the well while performing cleanout operations. In others, foam can be used to sweep the fill up. However there are still many wells that either cannot hold a foam column, or where foam use is restricted due to logistics reasons (e.g. procurement and disposal of N2 foam). In these situations, the only existing cleanout solution is a concentric coiled tubing (CCT) service to power a downhole jet pump. Using CCT implies a high use of power liquid to move the fill out and is limited in length by the weight of the coil-in-coil assembly.
Examples of CCT techniques can be found in U.S. Pat. No. 2,548,616, U.S. Pat. No. 5,033,545, U.S. Pat. No. 5,269,384, U.S. Pat. No. 5,375,669, U.S. Pat. No. 6,263,984, U.S. Pat. No. 6,015,015, U.S. Pat. No. 6,497,290, U.S. Pat. No. 6,640,897, U.S. Pat. No. 6,712,150, U.S. Pat. No. 5,503,014, and WO 2005085580 A.
Embodiments of the invention aim to provide an alternative to CCT techniques while also extending the depths at which clean-out operations can be performed. An embodiment of the invention is based on the use of a downhole pump that is powered by a cable running inside the tubing conveyance.
SUMMARY OF THE INVENTION
One aspect of the invention provides apparatus for borehole cleaning, comprising:
a tubular conveyance for extending from the surface into a borehole to a region to be cleaned; a motor mounted at the end of the tubular conveyance that in use is introduced into the borehole; a pump connected to the motor and having a nozzle; a power cable extending trough the tubular conveyance from the surface to provide power to the motor;
the pump being arranged such that, when positioned in the borehole and operated by the motor, the pump withdraws material from the borehole through the nozzle and pumps it into the tubular conveyance to the surface.
A second motor and pump can be located in the tubular conveyance above the pump so as to provide extra lift to the material to be removed from the well. Additional ‘booster’ pumps can be added in this way up to the power limit of the wireline cable.
A gas supply line can extend at least part way along the inside of the tubular conveyance and be arranged to introduce gas into the material-laden flow in the tubular conveyance above the pump.
The apparatus can further comprise a filter between the nozzle and the pump to prevent large particulate material passing into the pump from the borehole. Preferably, the filter removes material of greater than 1 mm from the flow.
It is particularly preferred that the apparatus comprises means to move the nozzle when the pump is operated downhole. Movement of the nozzle can be used to further mobilize the fill and suspend it in the fluids in the well. The means can rotate and/or reciprocate the nozzle. A separate motor can be provided to enable this mobilizing movement. Alternatively, a mechanical connection to a rotor in the pump can be provided for this purpose.
Features can be provided on the outside and/or inside of the nozzle to accelerate the flow of material when operated downhole to aid in movement of solids.
The tubular conveyance is preferably coiled tubing.
Another aspect of the invention provides a method of cleaning a well using an apparatus as defined above, comprising:
extending the tubular conveyance into the borehole so as to position the nozzle in a region to be cleaned; operating the pump so as to draw fluid and solid material from the region and pump them to the surface through the tubular conveyance.
The method can further comprise injecting gas into the materials in the tubular conveyance to create foam of reduced density to assist pumping of the materials to the surface.
Preferably, the solid materials are agitated downhole to improve removal by the pump.
The nozzle can be rotated or reciprocated while operating the pump.
Alternately advancing and withdrawing the tubular conveyance over a limited distance can be used to reciprocate the downhole end of the conveyance in the region to be cleaned.
In one embodiment, the tubular conveyance is extended until the pump is located at the bottom of a region to be cleaned and progressively withdrawing the conveyance to move the pump upwards through the region as the pump is operated. In another, the tubular conveyance is extended until the pump is positioned at the top of a region to be cleaned and progressively advancing the conveyance to move the pump downwards through the region as the pump is operated.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a schematic view of a well in which the invention can be used;
FIG. 2 shows a cross-section through the well on line 2 - 2 of FIG. 1 ;
FIG. 3 shows a schematic view of a system according to the invention deployed in a well;
FIG. 4 shows a detailed view of part of the system of FIG. 3 ;
FIG. 5 shows an embodiment of the invention for handling larger particulate materials in the fill;
FIG. 6 shows an embodiment of the invention for fill mobilisation;
FIGS. 7-11 show embodiments of features that can be added to a nozzle to improve fill mobilisation; and
FIG. 12 shows an embodiment of the system comprising a flow-diverter.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 3 shows the use of a system according to an embodiment of the invention in a well of the type shown in FIGS. 1 and 2 . The system includes a CT surface system 20 that reels a coiled tubing 22 into the well 24 through surface pressure control equipment 26 . An electrically powered motor 28 and pump 30 are located at the end of the CT 22 . A power cable 32 (see FIG. 4 ) runs from the surface to the motor 28 through the CT 22 for protection. The CT 22 also acts as a conduit for fluid/fill mixture removal. The pump 30 is configured to flow in the ‘reverse’ sense, sucking from the lower end and moving the fluid and fill solids upwards through the pump 30 itself and through the CT 22 towards the surface. The CT insulates the well from any pressure increase caused by the pump as it pumps fluid to the surface so avoiding damage to the formation. This can be particularly important in Low BHP reservoirs that can easily be damaged by relatively small increases in wellbore pressure above the in-situ reservoir pressure.
The power required to overcome the vertical height (TVD) hydrostatic pressure can be relatively large compared to the power usually available for downhole tools powered via an electric cable (e.g. wireline tools). Since 3-9 kW of electrical power is typically available to power the pump with current wireline technology, for a flow rate of 10 gpm (considered as suitable for this type of application), flow can only be assured for the first few kilometers (depending on CT size and fluid/fill density and viscosity). Therefore, an additional boost may be required to move the fluid mixture to the surface where it can be disposed of or separated.
One method of boosting the hydraulic power is to add a second pump/motor combination 34 in series with the first pump of an embodiment of this invention; either right next to it, or further up along the CT 22 . Another method of using dual pumps to carry cuttings during drilling has been disclosed in GB2416550A.
Another preferred method of assisting the fluid to reach the surface is to run a pilot line 38 partway along the CT (to point 36 ) to inject N 2 gas via a nozzle 40 . The length of this pilot line 38 can be determined a priori by knowing the geometry of the well, as it is preferable to inject the gas into the CT above the horizontal section. This will decrease the hydrostatic weight of the fluid above the injection point as the gas moves up, and will also avoid the risk of creating a gas ‘plug’ if the gas were injected lower (if the gas is injected in the horizontal section 42 , then the pump 30 will need to push the fluid and the gas up the CT 22 , thus increasing the system losses and causing a ‘slug’ flow condition where gas and fluid ‘slugs’ alternatively flow to the surface; leading to a less efficient carrying capacity system).
In the case of the sand plug where it is not possible to force the end of the CT 22 through merely by pushing the CT from the surface, pump operation can start from the top of the plug and the CT 22 slowly be run-in-hole to pump a mixture of well fluid and sand.
A mechanical sand mobilization means may be beneficial under this situation so as to fluidize the sand and make it easier to flow through the pump and up the CT. These are described below in more detail in relation to FIGS. 7-9 .
In the case of leftover drilling muds or heavy oils, then the apparatus can be run to the bottom of the well and pulled out of hole while the pump is operated. This will use the heavy fluids behind (i.e. above) the apparatus to act as a temporary dynamic seal and the removal of fluid from the lower part of the well can create a localized drawdown at that level. If the upper fluid is not viscous enough, then the drawdown will not materialize locally, but rather from a reduction of the well fluid level; in turn lowering the hydrostatic pressure over the entire well. If this is not desired, water or other appropriate fluid can be injected at the well head to compensate for the fluid removal through the CT.
During a clean-out operation, the apparatus may encounter pebbles and larger particles that have gravitated to the low side of the well and are mixed with the fill. One particular embodiment of the invention for use in such circumstances is shown in FIG. 5 . In this embodiment, the pump motor 50 is connected to the rotor 52 of a Moineau-type pump having an elastomer stator 54 . A junk basket 56 is added between the pump nozzle 58 and the pump 52 , 54 and can be used to retain the larger particles that might otherwise harm the pump or that cannot be effectively transported to the surface while still allowing through the finer fill encountered in the well. A typical pass-through particle diameter can be <1 mm.
The effectiveness of the mobilization of the fill can be greatly enhanced if a mechanical mixing of some sort takes place. There are various techniques that can be used for creating mechanical mobilization of fine particles and sand.
The surface injector can be used to stroke the CT backwards and forwards over a predetermined length (e.g. 1 foot (300 mm) as the nozzle is moved through the fill.)
A second motor can be provided at the tip of the pump tool to rotate the pump nozzle as is shown in FIG. 6 . In this embodiment, an electric motor 60 is positioned in the CT 62 near the nozzle 64 . The nozzle 64 is provided with a wire brush or mill 66 . Operation of the motor 60 rotates the nozzle 64 and brush or mill 66 to mobilise the fill.
Features can be added at or around the pump nozzle to mechanically agitate the fill as the nozzle is rotated. FIGS. 7-11 show examples of such features. In FIG. 7 , blades/scallops and threads 70 are formed around the outside and inside respectively of the nozzle 72 , serving to accelerate the fill as the nozzle 72 is rotated. In FIG. 8 , hard buttons 74 are provided around the nozzle 72 for the same purpose. In FIG. 9 , a brush 76 is connected to the pump rotor (not shown) and projects through the nozzle 72 into the fill. As the rotor rotates, the brush 76 rotates to mobilise the fill. These and/or other features can be used alone or in combination to improve mobilisation of the fill.
In another embodiment, pump hydraulic power can be used to create a slow reciprocating motion of the nozzle (via a low power turbine for example), that can assist mobilisation of the fill using features such as those described above.
FIG. 10 shows and embodiment in which the nozzle 80 (carrying a brush/mill 82 similar to that shown in FIG. 6 ) is linked to the lower part of the pump rotor 84 (for a Moineau-type positive displacement pump, for example) that is driven by an electric motor 86 . In use, some of the power of the motor 86 is used to rotate the nozzle and brush/mill 82 , the remaining power being used to pump the mobilised fill.
FIG. 11 shows one particular mechanism for converting the rotational motion of a pump rotor into reciprocating motion at the nozzle. In this embodiment, a Moineau-type pump having a rotor 90 and a stator 92 , the rotor 90 is driven by a motor 94 . The stator housing is extended at its lower end and carries a nozzle 96 mounted so as to be able to slide therein. Keys 98 positioned between the stator 92 and nozzle 96 prevent relative rotation of the stator and nozzle while allowing relative axial sliding. A rotatable J-slot holder 100 is positioned inside the nozzle 96 and connected to the pump rotor 90 by means of a drive shaft 102 . A J-slot 104 is provided in the outer surface of the holder 100 . A peg 106 projects from the inner surface of the nozzle 96 so as to engage in the J-slot 104 . As the holder 100 rotates with the rotor 90 , the peg 106 is forced to follow the path of the J-slot 104 , in turn causing the nozzle to move axially with respect to the stator 92 (the J-slot 104 and peg 106 act in the manner of a cam and cam follower to convert rotary motion into reciprocating motion). Depending on the particular design of the rotor and stator, various mechanisms can be used to provide the rotary drive to the nozzle. These can include simple drive shafts, shafts connected by universal joints, mutation disks and other such devices.
The limitation of how far the pump could be pushed in the well is usually the helical lockup of the CT in a deviated well. One way of circumventing this limitation is to combine an electric borehole tractor to pull the pump to depth, and then disengage and deactivate it to allow pumping while pulling the CT and pump back towards the surface. Hydraulic tractors can also be used when flowing in ‘standard’ (i.e. down the CT) circulation. However, their flow requirements can tend to increase BHP, which may be undesirable in very low pressure reservoir conditions.
The pump can also contain a flow-diverter 110 above it, best seen in FIG. 12 , that may be commanded from the surface via optical or electrical means, that would allow opening ports to the annulus to flow through the CT in cases when well control or CT cleaning is required. Once the CT has been cleaned, or any obstructions have been removed, the flow-diverter can close the ports and normal ‘reverse’ circulation can resume.
Even without the flow-diverter described above, flowing in the ‘standard’ direction from the surface can also be used to clean the filter of accumulated pebbles by ejecting them further up the wellbore and then moving the tool back down to the fill and proceeding with the clean-out operation.
It will be appreciated that the various techniques described above can be combined to give the described advantages. Other changes can be made while staying within the scope of the invention. | An apparatus for borehole cleaning comprises a tubular conveyance extending from the surface into a borehole to a region to be cleaned, a motor mounted at the end of the tubular conveyance that in use is introduced into the borehole, a pump connected to the motor and having a nozzle, and a power cable extending trough the tubular conveyance from the surface to provide power to the motor, The pump is arranged such that, when positioned in the borehole and operated by the motor, the pump withdraws material from the borehole through the nozzle and pumps it into the tubular conveyance to the surface. | 4 |
[0001] The present application is a continuation-in-part of U.S. application Ser. No. 12/291,441, filed on Nov. 11, 2004, and incorporated herein by reference.
BACKGROUND
[0002] Hammer unions are commonly employed to join pipe segments together. Typically, the wing nut component of the hammer union, which has a wing nut pipe segment with a threaded wing nut having integrated lugs, is tightened onto a male threaded pipe component by hammering upon the lugs. When the wing nut becomes unusable, it is usually necessary to remove the entire wing nut pipe segment from service.
[0003] It is standard practice to capture the wing nut on the wing nut pipe segment which prevents users from removing or replacing the wing nut. Once captured, the wing nut and the wing nut pipe segment are generally inseparable.
[0004] Often, before the full, useful life of the wing nut pipe segment is reached, one or more lugs on the wing nut will become deformed. A wing nut with one or more deformed lugs cannot reliably be mated to a male threaded piece of piping equipment. The piping equipment, however, would generally still be usable if the wing nut is replaced. At this time, there is no safe, field-installable wing nut that can be used to replace deformed, damaged or worn-out wing nuts which are captured on the wing nut pipe segment.
[0005] Currently, when a wing nut becomes deformed due to damaged or deformed lug(s), the end of the wing nut pipe segment on which the wing nut is installed is cut off, the deformed wing nut is replaced with a new wing nut, and the pipe is machined and welded together. Unfortunately, this repair approach often has quality problems. These quality problems lead to safety issues.
[0006] Safety of a joined hammer union is a major concern because hammer unions are often used to connect piping carrying large volumes of fluid under high pressures. Due to the internal forces on the pipe joint, hammer union joints commonly fail in an explosive manner. A misaligned wing nut on a hammer union joint may hold pressure for a period of time, but may ultimately fail as the pressure pushes against the joint.
[0007] An attempted field repair of a wing nut using common cutting and welding techniques creates a significant risk for misaligned or poorly welded joints. In normal field situations, there are few or no field personnel qualified to perform the highly skilled welding and machining operations required for a safe repair. Additionally, there is usually an absence of qualified welding and machining standards for field personnel to follow.
[0008] Since field repairs may result in significant down time, there is also an economic impact when removing a pipe section to replace a deformed wing nut. In manufacturing and drilling operations, down time directly impacts a company's cost of operations.
[0009] As identified herein, there is a need for a hammer union wing nut that does not require welding or machining. Additionally, there is a need for a field replaceable hammer union wing nut that may be easily and efficiently installed by field personnel.
SUMMARY
[0010] This disclosure provides a wing nut that requires no welding or machining operations. The wing nut may be installed in the field.
[0011] One embodiment discloses a wing nut including an arcuate body, an arcuate insert, a retaining ring, and a support member. The arcuate body defines a first portion of a mounting thread and the arcuate insert defines a second portion of a mounting thread. The arcuate insert is complementary to the arcuate body such that when connected to the arcuate body, the arcuate body and arcuate insert define an upper ring and a collar and the first and second portions of the mounting thread define a complete mounting thread for receiving a threaded male pipe end. The retaining ring is for securing the collar, and the support member is for securing the upper ring.
[0012] Another embodiment discloses a wing nut including an arcuate body, an arcuate insert, a retaining ring, and a support member. The arcuate body defines a first portion of a mounting thread. The arcuate insert defines a second portion of a mounting thread. The arcuate insert is complementary to the arcuate body such that when connected to the arcuate body, the arcuate body and arcuate insert define an upper ring and a collar and the first and second portions of the mounting thread define a complete mounting thread for receiving a threaded male pipe end. The retaining ring is disposed about the collar for securing the collar, and the support member is disposed about a pilot on the upper ring for securing the upper ring.
[0013] Still another embodiment discloses a wing nut including a first arcuate body, a second arcuate body, a retaining ring, and a support member. The first arcuate body has a first portion of a mounting thread thereon. The first arcuate body defines a radial arc greater than 180 degrees. The first arcuate body has a first and second clearance end defining a circumferential gap therebetween that is large enough for the first arcuate body to receive a pipe therethrough, wherein the first and second clearance ends have an acute angle.
[0014] The second arcuate body of this embodiment has a second portion of a mounting thread thereon. Further, the second arcuate body defines a radial arc complementary to the radial arc of the first arcuate body that when connected to the first arcuate body defines an upper ring and a collar. Still further, the second arcuate body has first and second mating ends for engaging the first and second clearance ends, wherein the first and second mating ends have an obtuse angle.
[0015] Continuing with this embodiment, the retaining ring is disposed about the collar defined by the connected first and second arcuate bodies. The first and second threaded portions define a complete connecting thread for receiving a threaded male pipe when the first and second arcuate bodies are connected. Further, the support member is adapted to engage a pilot on the upper ring that is defined by the connection of the first and second arcuate bodies.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is an exploded bottom perspective view of an embodiment of the wing nut.
[0017] FIG. 2 depicts a top plan view of an embodiment of an arcuate body.
[0018] FIG. 3 is a top plan view of an embodiment of the wing nut.
[0019] FIG. 4 is a cross-sectional view of an embodiment of the wing nut taken from FIG. 3 along line 4 - 4 .
[0020] FIG. 5 is an exploded plan view of an embodiment of the wing nut with a pipe section.
[0021] FIG. 6 is a top perspective view depicting an embodiment of the assembled wing nut.
[0022] FIG. 7 is a cross-sectional view of an embodiment of the wing nut installed on an un-threaded pipe segment with a shoulder.
[0023] FIG. 8 is a perspective view of an alternative embodiment of the wing nut including a support member.
DETAILED DESCRIPTION
[0024] This disclosure is directed to a wing nut that requires no welding or machining operations. The wing nut installation does not require any special qualifications or procedures, and can easily be accomplished by field maintenance personnel in normal field situations.
[0025] Generally, wing nut 10 is selected to correspond to a defined nominal pipe diameter. It is anticipated that a series of wing nuts 10 will be available for different sizes of pipes being employed.
[0026] Referring to FIGS. 1-8 wing nut 10 is generally comprised of arcuate body 12 , arcuate insert 14 , retaining ring 16 , and attachment devices 18 . Attachment devices 18 are used to connect, or join, arcuate insert 14 with arcuate body 12 . Arcuate body 12 may also be referred to as the first arcuate body 12 , and arcuate insert 14 may also be referred to as the second arcuate body 14 .
[0027] Wing nut 10 is preferably an alloy or carbon steel piece capable of withstanding high pressure when fully assembled and installed. Arcuate body 12 and arcuate insert 14 are preferably manufactured out of the same material. A non-limiting example of the material to form arcuate body 12 and arcuate insert 14 is to use a circular metal slug of hot-rolled grade 4340 steel. Retaining ring 16 may be manufactured from the same material as arcuate body 12 and arcuate insert 14 . However, retaining ring 16 is preferably manufactured out of a material different than that of arcuate body 12 and arcuate insert 14 . A non-limiting example is to use grade 4140 steel tubing for retaining ring 16 . Furthermore, retaining ring 16 preferably has material properties with specific capabilities as described herein. Wing nut 10 may be fabricated from other types of materials. These materials are preferably matched to a pipe size and have a desired pressure containment capability.
[0028] As depicted in the drawings, assembled wing nut 10 defines an annular body 20 with at least one lug 22 thereon. Annular body 20 , which may be referred to as upper ring 20 , has inner diameter 21 and first outer diameter 24 , and in the embodiment shown has three lugs 22 defined thereon. Assembled wing nut 10 has a collar 26 extending longitudinally from annular body 20 . Collar 26 may be referred to as lower ring 26 . Collar 26 has second outer diameter 28 , which is preferably smaller than first outer diameter 24 , so that shoulder 30 is defined by, and extends between, first and second outer diameters 24 and 28 . Wing nut 10 has a length 32 . Collar 26 has a collar length 34 that is shorter than length 32 . Collar 26 has a threaded inner surface 38 extending along collar length 34 to define mounting or connecting threads 40 , and has a collar thickness 42 . Wing nut 10 is thus compatible with a male thread 36 , and will receive a threaded male pipe segment as will be described in more detail herein.
[0029] As depicted in FIG. 2 , arcuate body 12 has an arc that is preferably equal to or greater than arcuate insert 14 , and that is at least circumferentially 180 degrees. The embodiment shown has an arc of approximately 220 degrees. Arcuate insert 14 will complement arcuate body 12 so that when assembled, arcuate body 12 and arcuate insert 14 comprise wing nut 10 and define upper ring 20 and collar 26 thereon.
[0030] Arcuate body 12 has a first clearance end 44 and a second clearance end 46 defining a gap or space 48 therebetween. Gap 48 will receive a pipe segment 50 therethrough. When pipe segment 50 is received through gap 48 , and arcuate body 12 and arcuate insert 14 are connected, the assembled wing nut 10 will provide fluid communication between pipe segments 50 and 52 when connecting threads 40 are properly mated with male threads 36 on pipe segment 52 .
[0031] Arcuate insert 14 has first and second mating ends 54 and 56 . First clearance end 44 of arcuate body 12 will mate with first mating end 54 of arcuate insert 14 . Second clearance end 46 of arcuate body 12 will mate with second mating end 56 of arcuate insert 14 . First and second seams, or joints 58 and 60 , are formed when arcuate insert 14 is inserted or positioned in gap 48 with first clearance end 44 adjacent to and engaging first mating end 54 , and second clearance end 46 adjacent to and engaging second mating end 56 .
[0032] Joints 58 and 60 are designed to ensure a tight seal between arcuate body 12 and arcuate insert 14 . Thus, it is preferred that joints 58 and 60 have a radially straight seam as depicted in FIGS. 2 , 3 and 6 . However, the shape of the seam between joints 58 and 60 is not limited to any particular shape or configuration. Joint 58 preferably has an exemplary angle 62 of about 13 degrees. However, it is understood that angle 62 may be any angle that allows arcuate body 12 and arcuate insert 14 to be joined. Similarly, joint 60 preferably has an exemplary angle 66 of about negative 13 degrees. It is also understood that angle 66 may be any angle that allows arcuate body 12 and arcuate insert 14 to be joined. In FIG. 2 , angles 62 and 66 are measured relative to horizontal centerline 64 .
[0033] Referring to FIG. 5 , attachment openings 68 and 70 are preferably threaded, countersunk attachment openings centered on joints 58 and 60 , and, referring to FIG. 3 , having a radial center point 72 positioned on upper surface 74 of assembled wing nut 10 . Preferably, radial center point 72 is positioned between first outer diameter 24 and inner diameter 21 . Attachment devices 18 are threaded connectors that will hold arcuate body 12 and arcuate insert 14 in place so that connecting threads 40 may receive male thread segment 36 , such as that on pipe segment 52 , to connect pipe segments 50 and 52 .
[0034] Arcuate body 12 and arcuate insert 14 each define a portion of connecting threads 40 as depicted in FIGS. 1 , 6 and 7 . Arcuate body 12 has first thread portion 76 of mounting thread 40 thereon, while arcuate insert 14 has second thread portion 78 of mounting thread 40 thereon. When arcuate body 12 and arcuate insert 14 are connected and aligned, first and second threaded portions 76 and 78 form connecting or mounting thread 40 . The alignment of first and second mounting thread 76 and 78 to form connecting thread 40 is facilitated by the insertion of attachment devices 18 into attachment openings 68 and 70 . In the preferred embodiment, connecting threads 40 are preferably machined into arcuate body 12 and arcuate insert 14 while they are joined. As will be understood, arcuate body 12 and arcuate insert 14 may be threaded prior to being machined from a single piece into the separate arcuate body 12 and arcuate insert 14 . Connecting threads 40 may also be part of a cast or forged wing nut 10 . As described above, connecting threads 40 are located on threaded inner surface 38 of collar 26 .
[0035] In the embodiments shown in FIGS. 1-8 , three lugs 22 are employed. A minimum of one lug 22 is required. The maximum number of lugs 22 is limited by the available circumferential space on annular body 20 . However, it is anticipated that the number of lugs 22 will typically be between two and four. Lugs 22 extend radially outward from annular body 20 . The spacing between lugs 22 is not critical in that lugs 22 may be uniformly spaced or not uniformly spaced.
[0036] FIG. 5 depicts a plan view of wing nut 10 with three lugs 22 and wing nut pipe segment 50 . FIG. 5 depicts wing nut pipe segment 50 positioned to be received by arcuate body 12 through gap 48 . In the preferred embodiment, wing nut pipe segment 50 is able to pass through gap 48 without external force applied. In other words, gap 48 has sufficient clearance for pipe segment 50 to pass therethrough.
[0037] Retaining ring 16 , depicted in FIGS. 1 , 7 , and 8 , is designed to secure arcuate body 12 and arcuate insert 14 in the assembled state. Retaining ring 16 is preferably comprised of a material having properties sufficient to resist the circumferential stress exerted upon it by arcuate body 12 and arcuate insert 14 , once installed. It is preferred that retaining ring 16 have a coefficient of thermal expansion sufficient to allow it to expand to an inner diameter that is greater than second outer diameter 28 of collar 26 when heated. The same coefficient of thermal expansion of retaining ring 16 allows it, when cooled to an ambient temperature, to return to an inner diameter less than second outer diameter 28 of collar 26 . Thus, when retaining ring 16 is heated and placed over collar 26 and then cooled, it will apply an inwardly directed radial force to collar 26 , and hold arcuate body 12 and arcuate insert 14 in place. Retaining ring 16 , when installed, will preferably have a thickness 82 about equal to the width 84 of shoulder 30 , and as such will have an outer diameter about the same as first outer diameter 24 of upper ring 20 . Retaining ring 16 preferably has a length similar to collar length 34 of collar 26 .
[0038] Referring generally to FIG. 8 , an alternative embodiment of wing nut 10 includes support member 90 associated with upper ring 20 for securing upper ring 20 . Support member 90 holds arcuate body 12 and arcuate insert 14 in place on an opposite side of wing nut 10 from collar 26 and retaining ring 16 . Support member 90 enhances the connection of arcuate body 12 with arcuate insert 14 to preclude any potential separation from the previously described radial and inwardly directed force applied to collar 26 by retaining ring 16 . In the embodiment shown in FIG. 8 , support member 90 is a ring-shaped member. However, support member can have different shapes and configurations for securing upper ring 20 , as discussed below. The materials described above for the manufacture of arcuate body 12 and arcuate insert 14 are also suitable for support member 90 .
[0039] In the exemplary embodiment of FIG. 8 , upper ring 20 has pilot 94 adapted to engage support member 90 for securing upper ring 20 , However, alternative embodiments for associating support member 90 with upper ring 20 are suitable as long as support member 90 engages both arcuate body 12 and arcuate insert 14 . By way of non-limiting example, support member 90 can engage both arcuate body 12 and arcuate insert 14 with pins or threaded fasteners.
[0040] Continuing with FIG. 8 , first portion 98 of arcuate body 12 and second portion 102 of arcuate insert 14 define pilot 94 when arcuate body 12 and arcuate insert 14 are connected to one another. Pilot 94 is shown as an integrally machined portion of upper ring 20 having a length that extends from an opposite side of upper ring 20 than collar 26 , described above. However, pilot 94 may alternatively be a separately connected component. In this embodiment, outer diameter 106 of pilot 94 engages inner diameter 110 of support member 90 for securing upper ring 20 , As shown, outer diameter 106 of pilot 94 is less than first outer diameter 24 of upper ring 20 .
[0041] As depicted in the embodiment of FIG. 8 , wing nut 10 has fasteners 112 for securing support member 90 to upper ring 20 . Fasteners 112 may be countersunk such that the head or surface of each fastener 112 resides below an outer surface of support member 90 and wing nut 10 when support member 90 is secured to upper ring 20 . As shown, fasteners 112 insert through mating lugs 114 around the circumference of support member 90 and connect to corresponding mounting holes 115 disposed in lugs 22 of upper ring 20 . Fasteners 112 may be, for example, any threaded fastener known in the art suitable for the environment and forces that will be applied to wing nut 10 in a particular application. Further, the present disclosure contemplates other methods for securing support member 90 to upper ring 20 , such as, for example, by welding or pinning.
[0042] Without limitation to any particular number of mating lugs 114 , FIG. 8 depicts three mating lugs 114 on support member 90 that connect to a corresponding number of lugs 22 on upper ring 20 . As shown, arcuate body 12 and arcuate insert 14 each define a lug 22 corresponding to a mating lug 114 on support member 90 . Securing support member 90 to both arcuate body 12 and arcuate insert 14 in this manner enhances the connection between arcuate body 12 and arcuate insert 14 .
[0043] Support member 90 may include stakes 116 to preclude loosening of fasteners 112 . In the embodiment shown, stakes 116 are portions of an outer surface of support member 90 deformed onto fasteners 112 . Although three stakes 116 are shown for each fastener 112 , the present disclosure is not limited to any particular number of stakes 116 . Stakes 116 may be provided in any convenient manner known in the art, such as, for example, by using a drift punch and a hammer to deform an outer surface of support member 90 onto fasteners 112 .
[0044] Similar to fasteners 112 , attachment devices 18 may be countersunk such that they reside below an outer surface of upper ring 20 and wing nut 10 when arcuate body 12 and arcuate insert 14 are connected to one another. Further, upper ring 20 of wing nut 10 may include stakes 116 that deform an outer surface of upper ring 20 onto attachment devices 18 to preclude loosening. Stakes 116 are not limited to any particular number and may be provided in any convenient manner as previously described.
[0045] A method of installing wing nut 10 may require initially removing a deformed or damaged wing nut from a wing nut pipe segment 50 . The damaged wing nut may be removed at any time prior to installing retaining ring 16 . Alternatively, the damaged wing nut may be moved axially on pipe segment 50 and left in place a sufficient distance from the end of pipe segment 50 to allow wing nut 10 to be installed. To install wing nut 10 , arcuate body 12 radially receives pipe segment 50 through gap 48 . Once pipe segment 50 is in place, arcuate insert 14 is inserted into gap 48 so that first and second clearance ends 44 and 46 of arcuate body 12 engage first and second mating ends 54 and 56 of arcuate insert 14 . Attachment devices 18 are threaded into attachment openings 68 and 70 , and are also used to align first and second mounting threads 76 and 78 . Once first and second thread portions 76 and 78 are aligned to form connecting thread 40 , the combined unit of arcuate body 12 and arcuate insert 14 is longitudinally moved along pipe segment 50 until it is positioned at pipe segment end 80 , thereby making collar 26 accessible.
[0046] Retaining ring 16 is heated to a temperature that allows it to expand to an inner diameter greater than second outer diameter 28 of collar 26 . The heated and expanded retaining ring 16 is slipped over collar 26 , and allowed to cool to an ambient temperature. In one non-limiting example, retaining ring 16 is heated to about 400 degrees Fahrenheit. It is preferred that retaining ring 16 be uniformly heated in a field oven or similar device. However, it is also acceptable to heat retaining ring 16 in any manner that creates near uniform thermal expansion without changing the material properties. After retaining ring 16 has radially retracted, pipe segment 52 may be threaded into collar 26 of wing nut 10 . Wing nut 10 is thus a field replaceable wing nut that requires no welding, or machining, and requires no special training of field personnel.
[0047] In the embodiments of wing nut 10 that include circular support 90 , an operator positions circular support 90 over pipe segment 50 prior to the step of installing arcuate body 12 and arcuate insert 14 as described above. Support member 90 is moved longitudinally along the length of pipe segment 50 and away from pipe segment end 80 to permit installation of arcuate body 12 and arcuate insert 14 between circular support 90 and pipe segment end 80 . After retaining ring 16 has been slipped over collar 26 and allowed to cool, as described above, inner diameter 110 of support member 90 is engaged with outer diameter 106 of pilot 94 . Subsequently, support member 90 is secured to upper ring 20 using fasteners 112 . Each fastener 112 connects through a mating lug 114 and into a mounting hole 115 disposed in a lug 22 on upper ring 20 .
[0048] Thus, it is shown that the apparatus and methods of the present disclosure readily achieve the ends and advantages mentioned, as well as those inherent therein. While certain preferred embodiments of the disclosure have been illustrated and described, numerous changes in the arrangement and construction of parts and steps may be made by those skilled in the art. All such changes are encompassed within the scope and spirit of the present disclosure as defined by the appended claims. | The present disclosure provides a wing nut including an arcuate body, an arcuate insert, a retaining ring, and a support member. The arcuate body defines a first portion of a mounting thread and the arcuate insert defines a second portion of a mounting thread. The arcuate insert and the arcuate body are complementary to one another such that when connected, the arcuate insert and the arcuate body define an upper ring and a collar and the first and second portions of the mounting thread define a complete mounting thread for receiving a threaded male pipe end. The retaining ring is for securing the collar, and the support member is for securing the upper ring. The wing nut is designed to replace an existing wing nut on a hammer union connection that has deformed lugs. The wing nut can be safely replaced in the field without any special equipment or training. | 5 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention concerns mechanical creping of wet-laid or dry form (air-laid) webs. More particularly this invention concerns controlling the mechanical creping process by employing two creping adhesives having properties different then each other.
2. Description of the Prior Art
Paper webs are conventionally softened by working them in different ways such as by mechanically creping them from a surface, usually a drying surface such as a Yankee dryer with a creping doctor blade. Such a process disrupts and breaks many of the inter-fiber papermaking bonds in the paper web which are formed during drying. These inter-fiber bonds are the principle source of strength in ordinary paper since very little strength results from the physical entanglement of the fibers.
Creping adhesives have been employed for adhering the webs to the creping surface sometimes in combination with release agents in order to control the degree of adhesion between the web and the creping surface. Control of the adhesion permits the continuous production of creped webs having substantially uniform characteristics imparted by the creping process.
Creping adhesives have also been used for adhering relatively dry paper webs to a creping surface since such dry webs do not have the usual natural adherence obtained by pressing wet webs to a creping surface.
The softness of paper webs has been increased by chemically impeding or preventing the inter-fiber papermaking bonds with a chemical debonder which also tends to weaken the sheet. Usually a wet or dry strength chemical is added to the sheet to make up for the strength loss caused by the chemical debonder. Unfortunately, the chemical debonders also tend to interfere with proper adhesion of the fibrous webs to a creping surface which tends to prevent creping of a chemically debonded web.
Creping adhesives have been added to the paper sheet or directly on to the creping surface to overcome the effect of the chemical debonder and obtain proper adhesion between the chemically debonded fibrous sheet and the creping surface.
The nature of the finished paper depends upon the mechanical forces at the locus of removal of the web from the cylinder, and also upon the angle of removal. Without a doctor blade or with a doctor blade substantially tangent to the circumference of the cylinder, the paper tends to have a smoother, "machine-glazed" finish. If the doctor blade is at an angle to the tangent, the finished paper is creped and this procedure is known as "creping off the Yankee drier."
In spite of the many desirable advantages which accrue in creping from Yankee driers, there is often much difficulty in maintaining smooth removal of the web by the doctor blade. This operation requires a delicate balance between the adhesive forces holding the web uniformly on the cylinder surface and the releasing forces occurring at the source of contact with the doctor blade. The creping forces can get out of balance. Too great of an adhesive force can result in "pickouts" of paper, or fibers remaining with the dryer surface and the inability of the cleaning doctor to remove sufficient adhesive from the dryer to avoid buildup of adhesive and an irregular surface. On the other hand, too little of an adhesive force can result in the paper being removed from the creping surface without sufficient creping action being applied to the web. Many attempts have been made to attain this needed balance but none have been entirely satisfactory. The present invention provides the desired control and balance.
SUMMARY OF THE INVENTION
A method is provided for mechanically creping a web from a creping surface by applying a layer of a first creping adhesive directly onto the creping surface, applying a second creping adhesive to the web, pressing the web onto the already formed layer of first creping adhesive to contact the second creping adhesive with the first creping adhesive for adhesively attaching the web to the creping surface, and creping the web from the creping surface. The invention also provides for the first creping adhesive to be relatively softer than the second creping adhesive so that when creping the web from the creping surface with a creping doctor blade, the blade tends to shear the layer of first creping adhesive rather than the second creping adhesive. The mechanical creping action can be controlled by adjusting (1) the quantity of first creping adhesive applied to the creping surface, (2) the quantity of second creping adhesive applied to the web and (3) the ratio of first and second creping adhesives.
BRIEF DESCRIPTION OF THE DRAWINGS
The FIGURE schematically illustrates a papermaking process employing the present invention.
DETAILED DESCRIPTION OF THE INVENTION
The drawing illustrates one type of conventional Fourdrinier papermaking machine with which the present invention can be used. The papermaking machine is illustrative of the double-felt type, on which paper furnish 10 flows from a headbox 11 through a slice 12 onto the substantially horizontal surface of a Fourdrinier wire 13 through which water is withdrawn and upon which web formation takes place. Wire 13 is entrained around breast roll 14 and over a plurality of table rolls 15 to a wire turning roll 16. It is then fed around a lower couch roll 17 and around to other guide rolls 18 back to breast roll 14. One or more of the above-described rolls is driven and propels the Fourdrinier wire 13 through the desired path so that the upper surface or flight moves from the breast roll 14 to the lower couch roll 17 and returns along the bottom. In addition, one or more vacuum boxes, deflectors, and hydrofoils (not shown) may be employed between table rolls 15 to assist in the removal of water from the web during its formation.
The wet web formed on the upper surface of Fourdrinier wire 13 is transferred to a pickup felt 20, which is pressed into engagement with the web on wire 13 by means of an upper couch roll 21. The pickup felt 20 meeting wire 13 moves in the same direction as the wire 13, as indicated in the drawings, and at substantially the same speed. Pickup felt 20 carrying the newly formed web is advanced through the nip of a press assembly, indicated generally by reference numeral 22. Felt 20 is then moved around a pressure roll 23 which may be of the suction type, and hence, is entrained around a plurality of guide rolls 24 back to upper couch roll 21. A guard board 25 and shower (not shown) are employed adjacent the surface of felt 20 in front of the point where it contacts the newly formed sheet and accomplishes pickup. Guard board 25 and the showers clean and condition the felt to receive the wet web.
Press assembly 22 comprises a upper press roll 26 and a lower press roll 27, one of which is a suction press roll. A wet felt 28 is entrained over a plurality of guide rolls 30 and over lower press roll 27. One or more of the rolls contacting wet felt 28 and pickup felt 20 is driven to insure movement thereof at the proper speed. Moisture is removed from the newly formed web in the nip of a press assembly 22 and transferred into wet felt 28. It is normally removed from wet felt 28 by a wringer roll 29.
The formed and pressed web on felt 20 issuing from the nip of press assembly 22 is then pressed into engagement with the surface of the rotating drying cylinder 31 of a conventional Yankee dryer. The Yankee dryer includes a hood 32 surrounding a portion of the surface of cylinder 31 contacted by the web. Hood 32 includes therein a plurality of air input nozzles 33 and an exhaust means 34 for removing air from the chamber enclosed by hood 32. This flow of air within hood 32 over the surface of the web carried on the drying cylinder 31 assists in removing moisture from the web and accomplishing drying. The paper web 35 shown issuing from the opposite side of drying cylinder 31 is removed from the surface of drying cylinder 31 by a conventional doctor blade 36 which accomplishes creping of the web. Web 35 is pulled from the vicinity of Yankee dryer 31 by passing the web 35 through a nip formed by a pair of rolls 42, from which it is conventionally wound into a roll 43.
With this description of a conventional Fourdrinier papermaking machine, the apparatus for applying creping adhesives in the manner of the invention will now be described. The creping adhesives are applied at two or more locations. The first location is by spray means 39 to the surface of the Yankee dryer 31, and the other location is by way of spray means 40 to the wet web carried upon pickup felt 20 and/or by application of the adhesive into the paper furnish 10 in the head box 11 by conventional means (illustrated by the pipe 41). The spray means 39 which applies the first creping adhesive to the Yankee surface 31 consists of a series of spray nozzles attached to a header pipe extending across the width of the Yankee surface 31 in a conventional manner. The nozzles are spaced apart from each other so as to have overriding spray patterns. By properly spacing the spray nozzles in a manner known in the art, the application of the adhesive is generally uniform across the width of the Yankee surface 31.
Spray application means 40 is provided by an apparatus similar in structure to spray means 39, but extending across the width of the pickup felt 20 at a point close to where the wet paper web is pressed to the Yankee surface 31 by press roll 23. The second creping adhesive applied through spray means 40 is applied to the surface of the wet paper web which will face the Yankee surface 31. As can be readily appreciated, the ratio of quantity of the first creping adhesive applied by spray means 39 to the quantity of second creping adhesive applied at spray means 40 can be accurately and quickly controlled by adjusting the flow at each spray means. The application of a third creping adhesive into the slurry, if desired, can be accomplished by well known conventional means, such as methods for the applicaton of wet strength resins, and is illustrated only schematically as pipe 41. After the paper web 35 is creped from the Yankee cylinder 31 by means of doctor blade 36, a residual film of creping adhesive remains on the Yankee surface 31. Most of this film is removed by conventional cleaning doctor 38, but a very thin uniform layer remains on the cylinder surface 31.
Spray means 39 are positioned as close as possible after the cleaning doctor 38 so that the first creping adhesive applied to the Yankee surface 31 will be heated by the Yankee surface 31 sufficiently before the wet web is applied to the Yankee surface to form a definitive layer of first creping adhesive upon which the paper web and the second creping adhesive are pressed. This definitive layer can be more satisfactorily formed if spray means 39 for spraying the first creping adhesive are positioned a significant distance from the location where the paper web is pressed to the Yankee surface 31.
The drawing shows the first creping adhesive being sprayed from sprayer tube 39 onto a rotating creping surface 31 which rotates clockwise. A continuous layer of this first creping adhesive is formed on the creping surface 31 prior to the point where the web is pressed against the creping surface. The first creping adhesive applied to the creping surface 31 should be applied at a rate of from about 0.01% to about 1.0% based upon the air-dry weight of the web.
While the first creping adhesive is shown in the figure as being sprayed onto the creping surface to form a layer on the surface, other methods of applying the creping adhesive to the creping surface are suitable including the use of fountain coaters, and reverse blade coaters which are well known.
With reference to the figure, the web 35 is pressed onto the creping surface 31 from pickup felt 20 by pressing roller 23. At this critical point of engagement of the web 35 onto the creping surface, the web already contains the second creping adhesive and a film of the first creping adhesive has already been formed on the creping surface 31. This aspect is the critical point of the invention. It is critical in practicing the present that:
1. a layer of first creping adhesive is formed on the creping surface;
2. the web is pressed onto the formed layer of first creping adhesive on the creping surface;
3. at the time when the web is pressed onto the layer of first creping adhesive, the web has already been treated with a second creping adhesive so that the pressing of the web contacts the second creping adhesive with the already formed layer of first creping adhesive.
The above critical sequence in the process of the present invention results in a web being adhesively attached to a creping surface by two discrete adhesives. While there may be some intermixing of adhesives at the adhesive interface, a layer consisting essentially of the first creping adhesive exists adjacent to the creping surface.
The web 35 is adhesively attached to the creping surface 31, rotates with the creping surface and is creped from the creping surface by a creping doctor blade 36. The creping doctor blade is urged against the creping surface 31 with a force sufficient to overcome the adhesive force of the web to the creping surface and accordingly the web is creped and removed from the creping surface.
A particular and unique advantage of the present invention is the controlability of the creping process to produce consistent uniform product. Because of the use of two distinct creping adhesives, the creping process can be controlled by adjusting the type and/or quantity of the first creping adhesive, and by adjusting the type and/or quantity of the second creping adhesive. Furthermore, the relative adhesive characteristics between the first and second creping adhesives can be adjusted in terms of there relative hardness or softness.
The present system permits the adhesive bond with the creping surface to be determined primarily by the characteristics of the first creping adhesive while the adhesive bond with the web is determined primarily by the characteristics of the second creping adhesive. These bonds can be separately controlled. Accordingly, the web can be tenaciously adhered with a hard creping adhesive while the creping blade can be cutting in the layer of the first creping adhesive to permit good removal without irregular surface buildup which causes plugging.
Problems usually associated with creping can be controlled with the present invention. For example a creping problem known as picking or plugging which results in holes in the paper and believed to be caused by excessive adhesion with the creping surface can be corrected by increasing the amount of the softer first adhesive applied to the creping surface. At other times the creped sheet may be too harsh with a blister type crepe indicating that the web is "too loose" or not adhered strongly enough to the creping surface. This condition can be corrected by decreasing the amount of first adhesive or increasing the amount of the second adhesive.
The film of the first should be softer than the second adhesive which results in the blade 36 riding in the layer of first adhesive and shearing the layer during the creping action. In such an embodiment, there remains on the creping surface, 31 immediately after the creping blade 36 a layer consisting essentially of the first creping adhesive. Most of this layer of the first creping adhesive is removed by a cleaning doctor blade 38 located behind the creping doctor blade 36 shown in the figure. A film having a glass transition temperature of less than about 30 10° C will be softer than adhesives suitable for use as the second creping adhesive.
In addition to individually controlling the adhesive bonds with the creping surface and with the web, the rheology of the film or layer of first adhesive can be adjusted independently of the adhesive bond imparted to the web by the second adhesive. Accordingly, the flow and shearing characteristics of the layer of first adhesive can be separately controlled. With such a system, the fibrous web can be tenaciously adhered by means of the second adhesive while the creping doctor blade can function in the layer or film of first creping adhesive which has film and shear characteristics independently selected to optimize the shearing of the film from the creping surface by the creping doctor blade.
The present invention produces a more uniformly and more extensibly creped web in comparison to employing only the first creping adhesive because of the superior adhesion of the web imparted by the second creping adhesive. Furthermore, superior product uniformity is obtained in comparison to employing just the second creping adhesive because of the superior shearing characteristics of the layer of first creping adhesive which permits controlled, uniform, consistent creping which minimizes chattering of the creping blade and plugging of the web.
Particularly good creping control is obtained when the first creping adhesive is a latex of a polymer that is essentially non-cross-linking. An example of such an adhesive is a non-cross-linking copolymer of vinyl acetate and acrylic esters. The latex is formed by emulsifying the copolymer that has been stabilized with a non-ionic hydrocolloid in the ratio of about 3 part by weight copolymer to about 1 part by weight hydrocolloid. The resulting latex is an emulsion of the copolymer and hydrocolloid having a large particular size (usually 1 micron). The presence of the hydrocolloid molecules in the emulsion imparts water redispersibility so that a dried film obtained from the emulsion is water redispersible when contacted with water and thereby tends to reemulsify. The advantage of using essentially non-cross-linking (thermoplastic) polymers is that the rheology of the thermoplastic polymer system in the emulsion is substantially retained when a dried film is formed of the emulsified components (non water components) even when the film is heated such as when the latex is sprayed onto the surface of a Yankee dryer.
Hydrocolloids suitable for use for imparting water redispersibility to emulsified copolymers are well-known in the latex art and are water soluble polymers that function as protectors in the formulation of an emulsion of a non-water soluble polymer and which tend to be electrochemically attached to the copolymer. Typical known hydrocolloids are hydroxyethyl cellulose, methyl cellulose, alginates and polyvinyl alcohols. An example of a non-water dispersible polymer that can be combined with a hydrocolloid and emulsified to produce a water based colloidal emulsion, the solid components of which produce a dried film that is redispersible in water is a vinyl acetate-acrylate copolymer available from National Starch Corporation as Latex No. 4441 or Latex No. 4442, which have a molecular weight of about 2,000,000, a glass transition temperature of about -40° C and a Sward Rocker hardness of about 3.
Water redispersible latexes, as exemplified above, should be a water based emulsion of a non-cross-linking polymer combined with a hydrocolloid so that a film of the solids in the emulsion (non-water components) is water redispersible, sufficiently soft to have a glass transition temperature lower than about -10° and preferably from about -20° C to about -50° C and have a Sward Rocker hardness between about 1 and about 4. Such polymers usually have a molecular weight of about 2,000,000.
Sward Rocker Hardness values and the test procedure are described in "Paint Testing Manual" G. G. Sward, Editor, ASTM Special Technical Publication -- 500 and also described in "Surface Coatings And Finishes" Gordon & Dolgin, Chemical Publishing Co., 1954.
There are particular advantages associated with employing the water redispersible latex adhesive described above as the first adhesive in practicing the present invention. Such latexes produce a particularly suitable film in which the creping doctor blade tends to ride and shear the film for creping the web from the creping surface and in addition any residue of the first creping adhesive which becomes deposited upon the papermaking felt or permeates other areas of the papermaking process is readily removable due to its water redispersibility. However, other adhesives are suitable for use as the first adhesive in practicing the invention provided they are softer than the second adhesive as can be indicated by a lower glass transition temperature for a film of the first adhesive than a film of the second adhesive. Relative softness between the two adhesives can also be determined by measuring the adhesive strength of each adhesive with the weaker adhesive being softer. Another good indication of relative softness is the modulus of elasticity. A lower modulus indicates a softer adhesive.
Latexes made from polymers capable of forming an emulsion in water either with or without normal emulsifiers are suitable. Preferably a film of the polymer solids has an initial modulus of less than about 2 × 10 7 dynes/cm 2 and a glass transition temperature less than about +10° C. The initial molulus referred to above is an initial modulus at 1% elongation for a film of a solid being tested according to ASTM Test D 638. Examples of suitable emulsion polymers (latexes) are water emulsions of acrylates; styrenebutadienes; polybutadienes; acrylonitriles; acrylontrile-butadienes; polyurethanes; ethylenevinyl acetates; polyvinyl alkyl ethers; polyacetals; polyterpenes; vinyl acrylics; ethylene-vinyl acrylates; polychloroprenes; polyhalohydrins; acrylate-acetate copolymers; plasticized polyvinyl chlorides and plasticized polyvinyl acetates. An example of a commercially available latex suitable for use as the first adhesive though it does not produce a water redispersible film is an acrylic ester copolymer emulsion available from Rohm & Haas under the tradename HA-8, having a glass transition temperature of about -13° C and an initial modulus of about 7 × 10 6 dynes/cm 2 .
Adhesives suitable for use as the second adhesive include the adhesives normally used as creping adhesives either added to the wet end of the papermaking process or to the web prior to contacting the creping surface. Such adhesives include the polyamines, polyamides, water soluble acrylates, animal glues, polyacrylamides, and polyacrylic-polyacrylamide copolymers. The above adhesives are water soluble have a viscosity in the range of about 50 cps to about 1,000 cps for solution having a solids content from about 7% to about 70% by weight; and a molecular weight of from about 150,000 to about 1,000,000.
The second adhesive when added to the wet end is added in amounts to result in from about 0.1% to about 4.0% adhesive based upon the air dry weight of cellulosic fibers in the furnish. When added directly to the formed web, the second adhesive should be added in amounts of from about 0.05% to about 4.0% based upon the air dry weight of the web.
The method of the present invention may be applied to a wide variety of webs in order to form creped sheet materials by the easily controllable process of the present invention. This means that a wide variety of processes may be utilized to form the web. The preferred means is by depositing fibers on a foraminous surface from a suspension in a fluid medium such as a water based furnish deposited upon a Fourdrinier wire as illustrated in the drawing. The invention is particularly suitable for creping wetlaid sheets whose natural fiber to fiber bonding in the formed web has been impeded or prevented either by chemical means (chemical debonders) or by the avoidance of wet pressing during the sheet formation and drying.
Suitable webs are preferably those having a basis weight between about 5 and about 55 pounds per 2,880 square feet. Such basis weight sheets particularly when chemically debonded derive the most benefit from the improved and controllable creping process of the present invention. | Mechanical creping of fibrous webs is improved by employing two creping adhesives applied at different points in the papermaking process and having relatively different adhesive properties for adhering the web to the creping surface. The process crepes the web from a conventional creping surface by applying a layer of a first creping adhesive directly onto the creping surface while applying a second creping adhesive to the web, followed by pressing the web onto the already formed layer of first creping adhesive and then creping the web from the creping surface. | 3 |
REFERENCE TO RELATED APPLICATIONS
This application claims priority to United Kingdom Patent Application 0606631.0 filed on Apr. 1, 2006, the entirety of which is incorporated by reference herein.
BACKGROUND TO THE INVENTION
The present invention relates to a paddle latch for a closure. Particularly, although not exclusively, the present invention concerns paddle latches designed to be installed on the doors of heavy plant containers and buildings where water ingress to the interior of the container or building is undesirable.
It is known to provide paddle latches on the doors of heavy plant containers or buildings containing heavy plant equipment such as generators or pumps. Paddle latches are suited to this application as paddles generally provide a large area with which to actuate the latch, which can be advantageous if the user is wearing protective gloves. Furthermore, the paddle latch acts as a latch and handle whereby the user only needs to pull on the paddle to both actuate the latch and open the door in the same movement.
Paddle latches often comprise a latch member which, when in a latched condition, engages with a feature on the door frame such that the door cannot be opened. The latch member is often mounted on a shaft such that it can rotate from a latched position whereby it engages the feature on the door frame to an unlatched position whereby it is clear of that feature and the door can be opened.
In known paddle latches, the latch member is often resiliently biased towards the latched position. Unlatching can be achieved by actuating the paddle which physically contacts the latch member overcoming the resilient bias and moving the latch member into an unlatched position whereby the door may be opened. It is also known for the interaction between the paddle and the latch member to only act to move the latch member into an unlatched position. Therefore when the paddle is in the closed position, movement of the latch member will not cause corresponding movement of the paddle. Consequently, the door can be closed and latched without any corresponding motion of the paddle. This is desirable as it is instinctive to apply a door closing force upon the paddle, and if it was to move in an opposite sense to the applied force, this movement would create both undue stresses on the components of the latch and would make closing the door more difficult.
In order to provide a slam function that allows the door to be shut without corresponding movement of the paddle, previous paddle latches have provided a mechanical interaction between the paddle and the latch member that is only effective in a single direction, such that movement of the paddle actuates the latch member from a latched to an unlatched position (in order to open the door), but movement of the latch member from a latched position to an unlatched position and back again (e.g. during door closure) does not cause corresponding motion of the paddle.
It is generally undesirable to allow water ingress into the container or building in which the equipment is stored. Heavy plant equipment such as generators and transformers do not respond well to the presence of water, and regulations stipulating levels of sealing on the containers or buildings are becoming ever more stringent. Water ingress can not only impair the operation of this equipment, but can also cause corrosion of metals. Furthermore, water can collect in sumps provided under such equipment, reducing their capacity for collecting oil, and resulting in oil over-flowing into the surrounding environment.
Items of heavy plant equipment such as generators often create a negative pressure environment inside the container or building as they operate, which results in a “suction” effect at any orifices between the exterior and the interior of a container or building. This suction effect draws in any water that may be present on the surface of the container or building resulting from rain fall or condensation.
Furthermore, items of heavy plant equipment (such as generators) often create a lot of noise. Any such noise can be transmitted from the interior to the exterior of the container via orifices and slots in latches. This noise can be disruptive, and cause discomfort to those in the vicinity of the container. It is therefore desirable to decrease the noise transmitted from the interior to the exterior of the container.
As discussed above, known paddle latches require that the paddle (normally located on the exterior of the building for access) and the latch member (normally located on the interior of the building such that it can contact a part of the door frame) have to be in contact in order for the latch to operate. The requirement for a mechanical interaction implies that there must be some kind of orifice or slot through which one of the components must pass in order to interact with the other. Furthermore, due to the motion of the components the orifice or slot is usually at least partially open in order to allow linear movement during operation.
Bearing in mind the requirement for sealing discussed above, the existence of such slots and orifices is disadvantageous in paddle latches.
SUMMARY OF THE INVENTION
It is an object of this invention to provide an improved paddle latch.
According to a first aspect of the invention there is provided a paddle latch comprising a housing defining a first side and a second side, a shaft extending through the housing defining a first shaft portion on the first side and a second shaft portion on the second side, a paddle for actuation by a latch user on the first side and a releasable latch member for co-operation with an associated striker to latch the, latch paddle on the second side wherein the paddle is connected to the first shaft portion and the latch member is connected to the second shaft portion such that torque may be transferred from the paddle to the latch member to release the latch member from the striker in use.
As discussed, known latches often comprise shafts on which the paddle rotates, but the interaction between the paddle and the latch member is normally a direct one giving rise to the necessity for large slots or orifices, which can cause water ingress into the container or building. The present invention overcomes this by allowing the drive shaft to transfer the force between the paddle and the latch member such that the only orifices that are required in the paddle latch are those through which the drive shaft must pass. This is advantageous as the drive shaft motion is only rotational and therefore orifices with a tight fit can be used, which may be more resistant to water ingress than prior art latches whilst still providing the required functionality.
Large slots of orifices can transmit noise from the interior to the exterior of the container, which is undesirable (as discussed above). The present invention mitigates this problem by allowing the drive shaft to transfer the force between the paddle and the latch member such that the only orifices that are required in the paddle latch are those through which the drive shaft must pass. Consequently as the drive shaft fits tightly inside these orifices, there is very little or no gap through which noise may pass.
A latch retention device will now be described in detail by way of example and with reference to the accompanying drawings in which:
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front elevation of a wall of a container comprising a door and a paddle latch in accordance with the present invention;
FIG. 2 is a perspective view of a paddle latch in accordance with the present invention;
FIG. 3 is a side section view of the latch of FIG. 2 in the direction denoted by III;
FIG. 3 a is a perspective view of a drive shaft for the latch of FIG. 2 ;
FIG. 4 is an end view of the latch with FIG. 2 with a partially cut-away section;
FIG. 4 a is a perspective exploded view of a drive shaft and latch arm for the latch of FIG. 2 ;
FIG. 5 is a bottom view of the latch of FIG. 2 ;
FIG. 6 is an end view of the latch of FIG. 2 ;
FIG. 7 is a side view of a part of the latch of FIG. 2 .
FIG. 8 a is a similar view to FIG. 7 showing the latch of FIG. 2 interacting with a striker in a latched position;
FIG. 8 b is a similar view to FIG. 8 a showing the latch of FIG. 2 in an unlatched position as actuated by a user;
FIG. 9 a is a similar view to FIG. 7 showing the latch of FIG. 2 interacting with a striker with the closure in an open position;
FIG. 9 b is a similar view to FIG. 9 a showing the latch interacting with a striker upon movement of the closure from an open to a closed position;
FIG. 9 c is a similar view to FIG. 9 b showing the latch of FIG. 2 interacting with a striker when the closure is in a closed position;
FIG. 10 is a section view of a drive shaft interacting with a latch arm according to a further embodiment of the latch of FIG. 2 ; and
FIG. 11 is a section view of a drive shaft interacting with a latch arm in accordance with the still further embodiment of the latch with FIG. 2 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1 a paddle latch 10 is configured for use with a door 12 on a container 14 .
The container 14 comprises a striker 15 (as shown in FIG. 3 ) with which the panel latch 10 interacts in order to secure the door 12 in a closed position. The striker 15 may take many forms but is generally a metal member or bar attached to the container 14 , or simply a portion of the door surround of the container.
Referring to FIGS. 2 to 6 , paddle latch 10 comprises a handle, commonly referred to as a paddle 16 , housing 18 , latch member 20 and drive shaft 22 .
The housing 18 comprises a housing body 24 and an attachment bracket 26 as depicted in FIG. 4 .
The housing body 24 is a moulded plastic or stamped metal component comprising a substantially flat flanged portion 28 , a first depression 30 and a further depression 32 formed therein. The first depression 30 comprises a small rectangular section 34 and an adjacent large rectangular section 36 . The small rectangular section 34 comprises a circular orifice 35 defined through two opposite side walls 39 , 41 thereof. The further depression 32 is substantially rectangular in shape.
A tab 37 as shown in FIG. 4 extends from an end face of the small rectangular section of 34 and substantially parallel with it. The function of the tab 37 will be described later.
The housing body 24 further defines two attachment posts 38 which project from the rear wall of the first depression 30 such that they are level with the further depression 32 . The attachment posts 38 are threaded internally.
When installed (as shown in FIG. 4 ), the flange portion 28 abuts the surface of the door 12 such that it is sealed against water ingress, optionally utilising a seal 29 . Attachment bracket 26 is mounted on the inside of the door 12 so as to abut the inner surface of the door 12 and the attachment posts 38 . Bolts 40 can then be threaded through washers 42 and through orifices (not shown) in attachment bracket 26 to be threadably engaged with the interior threads of the attachment posts 38 such that the paddle latch 10 is held in position.
The paddle 16 is constructed from a moulded plastic or stamped metal material and comprises handle portion 44 and hub portion 46 . The handle portion 44 is substantially wider than the hub portion 46 and when in the closed position sits within the large rectangular section 36 of first depression 30 within the housing 18 . The handle portion 44 is shorter than the large rectangular section of first depression 30 and consequently defines a finger hole 48 into which the operator's fingers may be inserted.
The hub portion 46 sits within the small rectangular section 44 of the first depression 30 . When the paddle 16 is in a closed position (as shown in FIG. 2 ) the surfaces of handle portion 44 and hub portion 46 are flush with the flange portion 28 of the housing 18 .
The handle portion 44 optionally contains a lock 50 extending therethrough and into the housing 18 through the first depression 30 into the further depression 32 . The lock 50 comprises a locking member 52 which may be rotated about the lock axis (denoted by broken line A in FIG. 3 ) following insertion of a key (not shown) such that the locking member 52 engages a feature of the further depression 32 such that the paddle 16 cannot be moved. This prevents the paddle latch 10 from being actuated and hence prevents the door from being opened.
The hub portion 46 extends into the first depression 30 of the housing 18 and defines a circular passageway 54 therethrough. The paddle 16 is positioned in the housing 18 such that it is able to rotate about the axis of the circular passageway 54 .
A drive shaft 22 is depicted in FIG. 3 a and comprises central a cylindrical section 56 , a first end section 58 and a second end section 60 , the end sections 58 , 60 being semicircular in cross section. The end sections 58 and 60 may be formed by, for example, a machining operation on circular bar stock. The drive shaft 22 further comprises a threaded hole 62 extending at least part way through the central cylindrical section 56 . The drive shaft 22 receives a grub screw 64 defining a complementary thread to that of the threaded hole 62 . The cylindrical section has a diameter to be a snug fit in passageway 54 and has a length sufficient to extend into the opposite walls 39 , 41 of the small rectangular section 34 of the housing 18 . Furthermore, the cylindrical section comprises a first o-ring groove 59 and a second o-ring groove 61 , into which drive shaft o-rings 63 fit (as shown in FIG. 4 ). The drive shaft o-rings 63 form a water and/or noise resistant seal between the interior and the exterior of the container.
The latch member 20 comprises a first latch arm 66 , a second latch arm 68 , a latch head 70 , a latch spring 72 , a return spring 73 and screws 74 .
The first latch arm 66 and the second latch arm 68 are constructed from sheet metal material and each comprise a head portion 76 , a centre portion 78 (substantially perpendicular to the head portion 76 ) and a base portion 80 (parallel to the head portion 76 ), such that the head portion 76 and the base portion 80 are offset by the length of the centre portion 78 as shown in FIG. 4 . The latch head 70 is configured to sit between the head portions 76 of the latch arms 66 , 68 . It comprises a moulded metal or plastic body defining four threaded holes 82 , which correspond to holes through the head portions 76 of the latch arms 66 , 68 . The screws 74 are inserted through the holes in the latch arms 66 , 68 and engaged with the threaded holes 82 of the latch head 70 as shown in FIG. 4 . In other embodiments the latch head may be adapted to suit various configurations of door and striker.
The base portions 80 of the latch arms 66 , 68 each comprise an orifice 84 defining a circle sector with an angle greater than 180° as depicted in FIG. 4 a . It should be noted that the shape of this orifice may vary greatly within the scope of the invention, and is generally dependent on the cross-sectional shape of the ends 58 and 60 of the drive shaft 22 , as will be described later.
In order to assemble the paddle latch 10 , the paddle 16 is inserted into the first depression 30 of the housing 18 as shown in FIG. 2 . The circular passageway 54 lines up with the circular orifices 35 in the walls of the small rectangular section 34 in the housing 18 . The axis on which these orifices lie is shown at R in FIG. 4 .
Orifices 84 of the base portion 80 of the latch arms 66 , 68 also line up with axis R, such that a passageway is defined through the latch arms 66 , 68 , the small rectangular section 34 , and the circular passageway 54 which receives the drive shaft 22 as shown in FIG. 4 . In this embodiment the drive shaft comprises seals (not shown) such as o-rings where it engages the housing in order to prevent the passage of liquid through the orifices 35 . In other embodiments for applications with less stringent sealing requirements, the seals may be omitted.
The latch member 20 is positioned substantially perpendicular to the closure 12 as shown in FIG. 3 with the base portion 80 of the first latch arm 66 abutting the tab 37 of the housing 18 as shown in FIG. 4 , such that it is able to rotate about the drive shaft 22 only in a clockwise direction from the state shown in FIG. 3 .
The latch spring 72 is threaded onto the drive shaft 22 such that it engages the second latch arm 68 and the flange portion 28 of the housing 18 as shown in FIG. 7 . The latch spring 72 therefore resiliently biases the latch member 20 in an anticlockwise direction when viewed in FIG. 7 (or alternatively a clockwise direction when viewed in FIG. 3 ) against the tab 37 .
The return spring 73 is threaded onto the drive shaft 22 such that it engages the drive shaft 22 and the flange portion 28 of the housing 18 . In this manner the return spring resiliently biases the drive shaft 22 (and therefore paddle 16 ) to its retracted position. The spring therefore need only be sufficiently strong to bias the paddle flush with the housing.
It should be noted that both springs 72 , 73 are located on the interior of the paddle latch 10 , and are therefore advantageously well protected from water damage which may impair their function.
Furthermore, the drive shaft 22 is rotationally positioned within the orifices 84 of the latch arms 66 , 68 such that the flat end sections 58 , 60 abut the corresponding surfaces of the orifices 84 , of the latch arms 66 , 68 so as to rotate the latch arms 66 , 68 when a torque is applied to the drive shaft 22 . As can be seen in FIG. 7 , rotation of the latch member 20 in a clockwise direction through its normal range of motion, would not cause a corresponding rotation of the drive shaft 22 due to the shape of the orifice 84 .
The paddle latch 10 is shown in FIG. 3 in a latched position. The door 12 is unable to open due to the interaction of the latch member 20 and the striker 15 . Rotation of the paddle 16 by an operator's fingers inserted into finger hole 48 causes rotation of the drive shaft 22 via the engagement of the grub screw 64 with the drive shaft 22 . This rotation causes the abutting surfaces of the drive shaft 22 and the latch member 20 to cause the latch member 20 to rotate as shown in FIGS. 8 a to 8 b.
FIG. 8 a shows a view similar to that of FIG. 7 with the shaft 22 cross-hatched and the latch member 20 hatched for clarity. The latch spring 72 abuts the flange portion 28 and the latch member 20 such that it is biased in an anticlockwise direction against the tab 37 . FIG. 8 b shows the condition whereby the paddle 16 has been used to rotate the drive shaft 22 by angle X. This rotation acts against the bias of the latch spring 72 and rotates the latch arm 20 by angle X moving the latch member 20 out of alignment with striker 15 such that the door may be opened (from the position shown in FIG. 8 b ).
The torsional restoring force of the latch spring 72 acts to bias the latch member 20 back to the position shown in FIG. 8 a . The torsional restoring force of the return spring 73 acts to bias the paddle back to its original position in order to avoid accidental damage as a result of its exposure.
The container 14 comprises a striker 15 (as shown in FIG. 3 ) with which the panel latch 10 interacts in order to secure the door 12 in a closed position. The striker 15 may take many forms but is generally a metal member or bar attached to the container 14 .
FIGS. 9 a to 9 c show a slamming event whereby an open door is required to be closed by pushing on the paddle 16 . In this situation it is undesirable for the paddle 16 to move for the reasons discussed above.
In FIG. 9 a , a force is applied to the door 12 or paddle latch 10 (usually by the paddle 16 ) in the direction shown by arrow F. In order for the latch member 20 to pass the striker 15 , the inclined surface on the latch head 70 slides along the striker 15 , causing the latch member 20 to rotate by angle Y as shown in FIG. 9 b . As the orifice 84 defines a sector of a circle substantially larger than the semi-circular profile of the corresponding flat end section of the shaft 22 , the latch member 20 can rotate freely without engaging the drive shaft 22 against the resilient bias of the latch spring 72 . When the door has closed far enough for the latch head 70 to pass the striker 15 , the resilient bias of the latch spring 72 causes the latch member 20 to return to its position abutting the tab 37 as shown in FIG. 90 . This entire sequence occurs without movement of the paddle 16 .
It should be understood that the angle of the sector defined by the orifice 84 should be greater than the maximum desired angle of rotation, Y, experienced when the door is closed in the manner described above. If this is not the case, then the latch member 20 will engage the drive shaft 22 actuating the paddle 16 , which is undesirable.
If, when in a closed position as shown in FIG. 3 , it is desired that the paddle latch 10 should be locked such that the door 12 cannot be opened, then the lock 50 may be engaged in a blocking position such that the paddle 16 cannot move and therefore it would not be possible to actuate the latch member 20 by using the paddle 16 . However, it should also be noted that if the lock is engaged whilst the door 12 is open, then it is entirely possible to slam the door in the manner described above, as the latch member 20 can rotate without engaging the drive shaft 22 . Therefore, it is not possible to damage any of the components of the paddle latch 10 by slamming the door 12 when the lock 50 is engaged.
It should be understood that the interaction between the drive shaft 22 and the latch member 20 may be defined by a wide range of geometries. Any interaction between the drive shaft and the latch member that results in torque being transferred with relative rotation of the two components in a first direction (e.g. if the drive shaft 22 is rotated clockwise from FIG. 8 a to FIG. 8 b ) but not in a second direction (e.g. if the latch member is rotated in a clockwise sense from FIG. 9 a to FIG. 9 b ) is within the scope of the invention. Optionally, at the point at which the drive shaft and the latch member interact, the drive shaft cross-section may define a circle sector with a first included angle, and the orifice in the latch member a circle sector with a second included angle. As long as the second included angle is Y° above the first included angle, where Y° is the maximum desired angle of rotation of the latch member, then the latch will operate. In the embodiment described here, the first included angle is 180° (a semicircle) and the second included angle is (180+Y)°. It should be noted that the first included angle may vary greatly within the scope of the invention. Examples of alternative geometries of drive shafts and latch members are described below.
FIG. 10 shows an alternative embodiment of the device whereby drive shaft 122 comprises a spline-type cross section instead of a flat end section. The corresponding orifice 184 on latch member 120 defines a spline with wider grooves such that rotation of the drive shaft 122 in a clockwise fashion will engage the latch member 120 but corresponding motion of the latch member 120 will not cause rotation of the drive shaft 122 .
FIG. 11 shows another embodiment of the invention whereby the shaft 124 comprises a protrusion 126 and the latch member 122 comprises a corresponding protrusion 123 in orifice 186 , such that clockwise rotation of the shaft 124 causes corresponding rotation of the latch member 122 but clockwise rotation of the latch member 122 will not cause rotation of the drive shaft 124 . Alternatively, the protrusion 126 of the drive shaft 124 could be provided via a key and keyway assembly.
It will be appreciated that by using the shaft to transfer torque from the paddle to the latch member means that only the shaft needs to extend from the exterior of the housing through to the interior. Inherently, it is far easier to seal this type of opening through the housing than the openings of known paddle latches, resulting in a latch that is cost-effective to manufacture, whilst achieving the desired sealing properties.
Numerous changes may be made within the scope of the present invention. Two examples of alternative drive shaft/latch member interfaces have been given in FIGS. 10 and 11 . The intention that any mechanical interface may be used as long as it provides torque transmission in a first direction but not in a second. Consequently, a large range of profiles of the drive shaft and corresponding orifice may be selected.
The lock 50 does not have to contact the housing to prohibit the movement of the paddle 16 , rather it may pass through the housing 18 and directly engage the latch member 20 when in a locked position.
The latch member 20 need not be in a vertical position when latched, the position may vary depending on the relative position of the paddle latch 10 and the striker 15 .
The biasing method used may vary from the torsional latch spring 72 . For example, a linear compression spring may be used between the latch member 20 and a corresponding surface of the housing 18 .
Different methods may be used to provide the mechanical connection between the paddle 16 and the drive shaft 22 . The grub screw 64 may be replaced with an interference fit between the drive shaft 22 and the paddle 16 . For example, the drive shaft 22 may be profiled to define a flat portion (such as seen in FIG. 3 a at 58 ) all the way along, and the paddle 16 may define a corresponding orifice such that rotation of the drive shaft 22 within paddle 16 is not possible.
This concept extends to the further examples shown in FIGS. 10 and 11 whereby the features of the drive shaft may extend along its length and the passageway 54 of the paddle 16 and may be adapted to engage them.
The application of the paddle latch 10 is not limited to doors but may be any type of closure. Correspondingly, a resilient biasing means (in this case latch spring 72 ) may not be present at all and the paddle latch 10 may be mounted such that the latch member 20 is restored to its latch position by action of gravity, or other suitable means.
The lost motion created between the end sections 58 , 60 of the drive shaft 22 and the orifices 84 of the latch arm 20 may alternatively exist between the centre portion 56 of the drive shaft 22 and an orifice in the hub portion 46 of the paddle 16 . In this instance, the drive shaft 22 and the latch member 20 would be fixably attached so as to rotate together.
In order to facilitate assembly, the drive shaft 22 may comprise two separate components for insertion at either side of the latch. In this way the drive shaft 22 would not have to pass all the way through the hub portion 46 of the paddle 16 .
The drive shaft o-rings 63 are provided to seal the circular orifices 35 . Alternatively, design tolerances and materials selection may be made such that sufficient relative motion and sealing is created without further sealing means.
The output from the shaft may be adapted to drive an alternative form of latch member, such as a sliding latch bolt. Also, either or both of the latch spring or the return spring may be replaced with resilient means integrated to the components which they bias. For example small, leaf-spring type structures could be machined in the orifices of the latch arm to interact with the drive shaft in this manner.
Locks are commonly employed in paddle latches for security reasons, but in certain embodiments may be omitted if so desired. | A paddle latch comprising a housing defining a first side and a second side, a shaft extending through the housing defining a first shaft portion on the first side and a second shaft portion on the second side, a paddle for actuation by a latch user on the first side and a releasable latch member for co-operation with an associated striker to latch the paddle latch on the second side wherein the paddle is connected to the first shaft portion and the latch member is connected to the second shaft portion such that torque may be transferred from the paddle to the latch member to release the latch member from the striker in use. | 4 |
[0001] This invention was made with United States Government support under Government Contract/Purchase Order No. DE-FC26-02NT41246. The Government has certain rights in this invention.
[0002] The present invention relates to fuel cells; more particularly, to an Auxiliary Power Unit (APU) including a solid oxide fuel cell (SOFC) system; and most particularly, to a Combined Heat and Power System (CHPS) for producing electric power and heating through combination of an SOFC system and a vapor-compression-cycle heat pump (VCCHP).
BACKGROUND OF THE INVENTION
[0003] Solid Oxide Fuel Cell systems are high-efficiency generators of electric power from a variety of fuels including Natural Gas, Liquified Petroleum Gas (LPG), Ethanol, and other hydrocarbon and non-hydrocarbon fuels. Due to the high operating temperature of an SOFC (700-900° C.), the tail pipe exhaust is generally also at a high temperature. A known state-of-the-art integration of SOFC systems is as part of a Combined Heat and Power System (CHPS). Prior art CHP systems use the electrical output of the SOFC system directly, and also utilize the energy leaving the SOFC system in the form of hot exhaust for heating air or water for space heating or for heating water for domestic usage (showers, etc).
[0004] No fuel cell system is 100% efficient, so there will always be heat leaving in the SOFC exhaust. For a typical 1 kW electrical service demand (e.g., a small residence), the heating or thermal needs are typically in the range of 5-10 kW. If the SOFC system has a reasonably good electrical efficiency, for example 33%, the heat output for 1 kW net electric output is 2 kW. Since 2 kW is much less thermal energy than desired, auxiliary direct-fueled condensing or non-condensing burner-heat exchangers are commonly used to make up the difference. The best of these are 80-90% efficient in converting fuel to electric and thermal energy.
[0005] What is needed in the art is an improved CHP system with increased overall fuel efficiency.
[0006] It is a principal object of the present invention to increase the fuel efficiency of a CHP system.
SUMMARY OF THE INVENTION
[0007] Briefly described, the invention seeks to improve the overall efficiency of a CHP system with respect to conversion of fuel energy to usable heat and electrical energy. In addition, a method to flexibly close the gap between thermal energy available vs. thermal energy demand is presented without the need for an accessory burner-heat exchanger system. The invention is directed to an improved CHP system which combines a VCCHP system with an SOFC system, both of which are well known in the art, for application as a combined CHP system wherein the compressor motor of a heat pump is powered by a portion of the electricity generated by the SOFC, and wherein the thermal output of the heat pump is increased by abstraction of heat from the SOFC exhaust. This integration allows for novel and complementary operation of each type of system, with the benefits of improved overall fuel efficiency for the improved CHP system.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The present invention will now be described, by way of example, with reference to the accompanying drawings, in which:
[0009] FIG. 1 is a schematic drawing of a first exemplary CHP system in accordance with the invention;
[0010] FIG. 2 is a diagram of a second exemplary CHP system wherein the evaporator section of a VCCHP is interfaced with system process air;
[0011] FIG. 3 is a diagram of a third CHP system embodiment wherein the evaporator section of a VCCHP is interfaced only with SOFC exhaust which is tempered by mixing with intake system process air;
[0012] FIG. 4 is a table showing total percent efficiency of a CHP system in accordance with the invention as a function of electric demand and compressor power; and
[0013] FIG. 5 is a table showing kW thermal output of a CHP system in accordance with the invention as a function of electric demand and compressor power.
[0014] Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate currently preferred embodiments of the invention, and such exemplifications are not to be construed as limiting the scope of the invention in any manner.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0015] Referring to FIG. 1 , a schematic drawing of a first exemplary CHP system embodiment 10 in accordance with the invention is shown. A solid oxide fuel cell system 12 as is well known in the fuel cell arts is provided with a supply of fuel 14 and air 16 . Fuel 14 is typically a hydrocarbon fuel conventionally available in liquid or gaseous form such as an alkane or alcohol. It is also known to fuel an SOFC directly with ammonia, obviating the need for a reformer. SOFC 12 provides electric power 18 and also emits a hot exhaust 20 that is directed through one side of a heat exchanger 22 , creating a partially-cooled exhaust 24 that may be discharged to atmosphere 26 .
[0016] A VCCHP system 28 includes conventionally a compressor 30 driven by an electric motor 32 ; a heat exchanger condenser 34 ; an expansion valve 36 ; and a heat exchanger evaporator 38 . VCCHP system 28 may be of a prior art type with a suitable refrigerant (first working medium). As used herein, a “working” medium is a fluid medium recirculated in a closed loop. The first working medium is pumped as a gas through a first side of heat exchanger/condenser 34 wherein the medium is condensed to a heated liquid wherein the heat of vaporization is recovered. A second thermal carrier fluid medium 41 is pumped by a recirculation pump 35 through the second side of heat exchanger/condenser 34 , abstracting heat from the hot first working medium, and thence through a customer application 37 requiring heated fluid 39 , for example, hot air, hot water, or hot refrigerant. The second fluid medium may be in a closed system wherein heat is extracted therefrom in customer application 37 and the medium is then returned 43 for reheating; or application 37 may consume the heated second working medium, in which case fresh cold medium is supplied to recirculation pump 35 . Advantageously, the second fluid medium is also passed through the second side of heat exchanger 22 wherein the second fluid medium is further heated by abstraction of waste heat from hot SOFC exhaust 20 . The thermal output of VCCHP system 28 is thus augmented by heat from exhaust 20 in accordance with the invention, and thus the thermal efficiency of the overall CHP system is substantially increased.
[0017] In addition, a portion or all 40 the balance of the SOFC exhaust heat 24 may be channeled to the evaporator 38 of the heat pump system, thus providing an additional temperature sink for the remainder of the SOFC heat before final exhaust 26 ′. This provides additional efficiency, and/or expanded operating range for lower outdoor or low temperature reservoir temperatures.
[0018] In operation, electric compressor motor 32 is driven by a portion of the electric power 18 of SOFC system 12 . The heat pump system drives evaporator 38 to a temperature below the temperature of a low temperature reservoir 52 or SOFC exhaust 40 , causing heat to flow to the first working medium. The compression process condenses the first working medium and increases the temperature thereof to a temperature above a high temperature reservoir. The condensed high temperature medium then passes through condenser 34 which has heat exchange with a high temperature reservoir defining a thermal carrier medium, for example, space heating air or coolant or water for circulation heating in customer application 37 . A separate water loop may be channeled through the condenser to handle domestic water needs (showers, drinking, etc.). In this way, heat from both the low temperature reservoir 52 , 40 and electric power 18 are channeled to the high temperature reservoir (coolant, water, or air 39 ). The amount of heat transferred from the low temperature reservoir to the high temperature reservoir is a function of the amount of compression power (assuming non-limiting cases in heat exchangers etc.).
[0019] For a heat pump system, a coefficient of performance (COP) is defined as the heat output to the high temperature reservoir divided by the heat, or work, driven into the refrigerant by the compressor. COPs for good heat pump systems are typically between 2 and 3. This means that 2 to 3 times the electric power (minus motor losses) driven to the compressor is driven to the high temperature reservoir (air, coolant, or water). This is a primary efficiency improvement for the utilization of fuel power to heat power.
[0020] Heat exchanger 22 may be separate from VCCHP system 28 or may be an integrated heat exchanger with condenser/exchanger 34 used to transfer the SOFC exhaust heat to the same heating air, coolant, or heating water. Since the SOFC exhaust 20 is at a higher temperature than the condenser 34 of the heat pump system, additional heat flows from the exhaust of the SOFC to the coolant. Where constant massflow of coolant or air is desired at a prescribed temperature, the heat pump compressor may be driven at variable speed to adjust the heating load depending on demand or operating conditions. By this method, a novel simple control may be obtained for either constant temperature or constant massflow heating needs under variable demand or environmental conditions.
[0021] Note that with the addition of a compressor reversing valve (not shown but well known in the prior art) in the refrigerant loop of VCCHP 28 , the heat pump may be reversed, and condenser 34 becomes the evaporator, and evaporator 38 becomes the condenser. Heat exchanger 22 is bypassed, and the hot SOFC exhaust is not used with the VCCHP 28 ; SOFC electrical output 18 , however, continues to power the pump compressor. In this way, electrical air conditioning, or water or coolant chilling, may be provided during warm months where heating is not needed. This provides additional features to the customer not provided by any prior art CHP system, all of which are limited to electric power generation and heating.
[0022] FIG. 2 shows an exemplary second embodiment 110 of an SOFC Heat Pump CHP system in accordance with the invention. A key feature is the integration of the heat exchanger for evaporator 138 with the process air inlet and exhaust streams 152 , 154 , respectively, of the device. Thus, separate heat exchanger 22 ( FIG. 1 ) is omitted, and all heat from SOFC exhaust 20 is entered into the heat pump through extraction by evaporator 138 .
[0023] An SOFC system normally intakes both process air and auxiliary cooling air (cabinet, electronic, and space cooling) from an external source and vents the hot exhaust to a suitable outside air space. In this embodiment, the evaporator also draws heat out of the process air 152 coming into the system. This low temperature air is used for cooling and SOFC system operation. The lower temperature process air intake 152 improves the efficiency of the SOFC air pumps and blowers as well as improving the cooling of onboard electronics and other devices. The heat entering evaporator 138 from this stream becomes available to the application at the condenser 134 through the heat pump system operation. The hot system exhaust stream 20 also travels through evaporator 138 giving additional heat input to the heat pump process (analogous to stream 40 in FIG. 1 ). This integration allows for access to the low temperature heat source in the outside air without having to place an evaporator outside of the system or appliance boundary 160 , or directly outdoors. This integration also improves system cooling and allows for efficient use of system exhaust heat. The specifics of the ducting and heat exchanger technology are not critical to the invention, but use of concentric inlet and outlet ducts and multi-pass heat exchangers enhances the functionality and performance and are obvious to those skilled in the art.
[0024] Referring to FIG. 3 , an exemplary third embodiment 210 in accordance with the invention is generally similar to first embodiment 110 but outside air 16 bypasses evaporator 238 and passes directly to SOFC 12 as process air and cooling air. Additionally, air intake plenum 252 includes a diversion plenum 270 connecting the outside air 16 with hot SOFC exhaust 20 such that a portion of the intake air may be diverted ahead of SOFC 12 and mixed with the SOFC exhaust in a mixing zone 272 to adjust the temperature of heating gas being passed through evaporator 238 . Exemplary steady-state operating temperatures are provided for various locations in system 210 .
[0025] System efficiencies and thermal outputs of a combined SOFC and VCCHP CHP system in accordance with the invention are shown in FIGS. 4 and 5 for variable electric demand. Note that the first row of these tables, wherein compressor input is 0 kW, represents a prior art CHP system wherein the heat in the system exhaust is recovered via an auxiliary burner-heat exchanger. Thus it is seen that for the typical prior art CHP case without a heat pump, thermal output is low at low electric loads, and is insufficient to meet high thermal demand at any electrical load; hence the need for the supplemental burner. In the present invention, the thermal demand may be met with high efficiency at low to moderate electrical demand through use of a VCCHP. This is a primary advantage of the invention.
[0026] While the invention has been described by reference to various specific embodiments, it should be understood that numerous changes may be made within the spirit and scope of the inventive concepts described. Accordingly, it is intended that the invention not be limited to the described embodiments, but will have full scope defined by the language of the following claims. | A Combined Heat and Power System (“CHPS”) includes a solid oxide fuel cell system and a vapor compression cycle heat pump. The CHPS improves the overall efficiency of a CHP system with respect to conversion of fuel energy to usable heat and electrical energy without need for an accessory burner-heat exchanger system. The compressor motor of the heat pump is powered by a portion of the electricity generated by the SOFC, and the thermal output of the heat pump is increased by abstraction of heat from the SOFC exhaust. This integration allows for novel and complementary operation of each type of system, with the benefits of improved overall fuel efficiency for the improved CHP system. | 8 |
This invention concerns liquid transfer devices and, more particularly, volume definition in such devices used for biochemical diagnostic testing in extra-laboratory situations.
BACKGROUND OF THE INVENTION
A number of such devices for manual operation have been developed in recent years, these being designed to avoid any need for complex procedures, and thus be suitable for use by lay persons. For example, to avoid the necessity of a timed sequence of reagent additions to an analyte, devices have been developed to automatically sequentially deliver such reagents by use of multiple capillary flow channels. Examples of these capillary flow diagnostic devices are further described in Patent Specification WO90/11519 and in co-pending UK Patent Applications GB-2261283 and GB-2261284.
In some applications of devices of this type a user is looking for a simple colour change to confirm the presence of a specific analyte in a sample. In others, the user may be seeking a quantified result such as a certain degree of colour change, and it is in these latter applications that a need arises to accurately measure out, or define, a desired volume of the sample onto the device.
Currently, the sample volume is measured out and applied to an analytical site of the diagnostic device, the analytical site comprising a quantity of antibodies immobilised within a specific region. The volume measuring is done using a hand pipette or capillary tube. Pipettes are expensive precision instruments and considerable skill is needed to achieve accurate results. Capillary tubes are less expensive, and may include a porous plug to define the sample volume. However, they are usually made of glass and therefore readily breakable in mass usage, and in any case an inexperienced user can find them difficult to use.
If an undefined amount of sample is applied to an analytical site, then there may well be an `error volume` of sample deposited beyond the boundaries of the immobilised region. This is in general terms unlikely to create a major inaccuracy with respect to sample lying downstream or laterally of the immobilised region, but error sample lying upstream of the immobilised region will be passed by liquid flow through the region and there may be reaction between the antigen of interest contained therein and the antibodies at the analytical site, thus ultimately leading to an inaccurate result.
One known method of sample volume definition is to incorporate a manually operated valve mechanism, which shears off a defined volume of sample in;to the diagnostic device. Such a device is described in M. P. Allen et al, Clinical Chemistry 36 (1990) p.1591-1597. The measuring out of sample volume is thus automatically realised and possibilities for error are thus greatly reduced. However, the mechanism involves precision moving parts and is thus relatively expensive to manufacture.
SUMMARY OF THE INVENTION
It is an object of the present invention to achieve volume definition in a manner that is simple, inexpensive, automatic and which avoids the use of mechanical moving parts, and which is of a type compatible with currently available diagnostic devices.
According to one aspect of the invention, there is provided a capillary flow liquid transfer device comprising a first flow channel leading from a first channel end to a volume determination site and a second flow channel leading from a second channel end and crossing said first channel in an interception area bordering said volume determination site directly upstream thereof relative to flow in said first channel, the channels being arranged so that, subsequent to simultaneous liquid application at said first and second channel ends, liquid flow in said second channel reaches the interception area, before that in said first channel.
With this arrangement, applied substance whose volume is to be defined, such as sample, extending beyond the volume determination site into the interception area, will be carried away by liquid flow in the second channel before liquid flow in the first channel arrives at the interception area.
This provides effective volume definition, since excess volume, which might otherwise upset a quantifiable result of a diagnostic test carried out with the device, will be removed before, say, a reagent is delivered to the volume determination site. Unlike prior art volume definition techniques which simply confine a desired quantity of, say, sample, the invention ensures that excess volume is hydraulically removed in a procedural step automatically initiated by use of the device.
In a preferred embodiment a third flow channel is provided, leading from a third channel end and crossing said first channel in a further interception area bordering said volume determination site directly downstream thereof relative to flow in said first channel, said third channel being arranged so that, subsequent to simultaneous liquid application at said first, second and third channel ends, liquid flow in said third channel reaches said further interception area before that in said first channel.
With such a device, excess volume extending beyond the volume determination site into the further interception area will be carried away by liquid flow in the third channel before liquid flow in the first channel arrives at the further interception area.
The provision of both the second and third flow channels bordering the volume determination site both upstream and downstream thereof relative to flow in the first channel allows balancing of the hydraulic pressures over the volume determination site and this prevents liquid flow in the second and third channels from being diverted into the volume determination site.
Commonly, the applied substance whose volume is to be defined is a sample of blood serum or urine, but may be for example a reagent whose volume is required to be defined for subsequent delivery to a sample, or a diluent, whose volume is to be defined for subsequent delivery to a reagent or sample.
Preferably the second channel and/or the third channel, after crossing the first channel, lead(s) to a waste reservoir. This reservoir receives the flow carrying away excess volume from the interception area or areas.
In order to check the satisfactory functioning of the device, it may comprise means for indicating to a user the contents of the waste reservoir. This may be a plurality of windows which give a view of the waste reservoir through a device housing, and provide a visual indication of the amount of a given substance within the waste reservoir.
Preferably, the flow channels of the device are conformed to prevent liquid flow in the first channel being diverted by flow in the second and/or third channel, and this may be done by including at least one further flow channel in the device to provide hydraulic flow balancing.
In a further aspect of the invention, there is provided a first liquid transfer means for transporting liquid by capillary action to a site defined by boundaries, at which site a substance is to be applied;
applying substance in a quantity at least sufficient to fill said site such that substance may extend beyond the boundaries of said site; and
providing second liquid transfer means that, once said first liquid transfer means is operated, automatically transports liquid by capillary action to entrain and remove substance extending beyond the boundaries of said site before said first liquid transfer means has transported liquid to said site.
The substance may be applied to the site by way of a separation membrane through which selected constituents may travel.
BRIEF DESCRIPTION OF THE DRAWINGS
Specific embodiments of the invention will now be described by way of example with reference to the accompanying drawings in which:
FIGS. 1a and 1b represent one embodiment of a device according to the invention;
FIG. 2 represents a second embodiment of such a device;
FIG. 3 depicts an electrical circuit analogue of the device shown in FIG. 2; and
FIGS. 4a-7b represent respective further embodiments with respect to biochemical assay procedures.
DETAILED DESCRIPTION OF THE INVENTION
FIGS. 1a and 1b shows an analytical test device 1 comprising a sheet of porous material for carrying out sequential delivery of two reagents X and Y to an analytical site S. The device features a number of interconnected channels, four of which, A,B,C and D, are formed as `legs`, the free ends of which are adapted to be simultaneously introduced to a liquid reservoir 2 which contains an appropriate buffer solution. A transverse common channel E links the other ends of these four legs and in this channel are located sites for reagents X and Y, between the ends of pairs of legs A and C, and C and D, respectively.
The volume determination site is a sample site S, which in this case is the analytical site, and is located in a portion of channel E between the ends of legs A and B. Typically at this position an antibody is held which is capable of reacting with an antigen of interest contained in the applied sample.
When liquid is introduced to the ends of legs C and D it is drawn up through the porous material by capillary action until it reaches transverse channel E, along which it then moves towards analytical site S, solubilising and entraining reagents X and Y such that they are subsequently delivered in turn to the analytical site. This basic technique of automatic sequential delivery is disclosed in the above mentioned publication WO 90/11519 and reference can be made thereto for more specific details of such devices.
A fluid sample, which may be urine or blood serum, say, is applied to analytical site S before the device s activated. This may be accomplished by depositing a quantity of sample on an application `window` realised in a housing (not shown) surrounding the porous material of the test device. Analytical site S is defined by the immobilised antibody region, but it is likely that excess sample 3 will also find itself deposited in or ingressing into the porous material, this excess sample being capable of affecting the diagnostic procedure such that a false result may ultimately be obtained. Legs A and B are arranged symmetrically of analytical site S as shown in FIG. 1 and the device also features additional waste channels F and G which extend transversely from channel E on either side of site S and on the opposite side of channel E from legs A and B. Transverse flow channel E continues downstream beyond analytical site S into waste channel H where waste products from the reactions are ultimately washed.
The operation of this device can be seen from FIG. 1b. Upon activating the device (by simultaneously introducing the ends of legs A,B,C and D to liquid reservoir 2) liquid flows by capillary action along all four legs and into transverse common channel E. Liquid from legs A and B flows past analytical site S and into waste channels F and G respectively, and in passing through notional `interception` areas bordering the analytical site S on either side thereof, this flow entrains, or `slices off`, excess sample 3, and carries it away into the waste channels F and G, leaving only the defined quantity of sample corresponding to the immobilised region at the analytical site. Subsequently reagents X and Y, solubilised by liquid flow from channels C and D are delivered successively to the analytical site and incubate with the defined amount of sample to produce an indication of detected content for the user, before all waste products are washed by the continuing flow into waste channel H. Meanwhile, excess sample 3 remains trapped in waste channels F and G and is not redirected by diffusion and subsequent flow into the sample site. It therefore has no further part in the process. It is important therefore that in such devices the flow carrying removed excess sample has stopped before wash liquid and subsequent reagent begins to flow at the analytical site.
In actual fact experimentation has shown that the delivery of reagents to the analytical site is distorted by the flow from legs A, B and C (shown by dotted lines in FIG. 1b), and to reduce this problem an improvement to the hydraulic circuit of the device is shown in FIG. 2. In this embodiment transverse channel I connects the end of leg D with the analytical site S, whilst additional transverse channel J connects the end of leg C with the ends of legs B and A. Parallel transverse channels I and J are interconnected at nodes N 1 and N 2 as shown in FIG. 2. Channels I and J continue downstream into common waste reservoir T.
It is well understood that hydraulic flow and pressure are analogous to electrical current and voltage, with hydraulic resistance to flow equating with electrical resistance. However, the hydraulic flow in porous media exhibits some laminar characteristics and forms separate subflows within the various channels. FIG. 2 represents the hydraulic resistances R 1 to R 10 of each portion of the hydraulic circuit, and the electrical analogue circuit is given in FIG. 3. As can be appreciated from this figure, the circuit comprises electrical resistors R 1 to R 10 and incorporates a double electrical bridge, and by careful selection of the relative values of these resistors null currents can be created at nodes N 1 and N 2 . In the equivalent hydraulic circuit the result of an analogous hydraulically balanced arrangement is therefore to achieve null flow between transverse channels I and J at nodes N 1 and N 2 once these channels are saturated. It will be appreciated that the flows in channels A and B and the subflows downstream of the sample region at T (shown by dot-dash lines), also contribute to the flows in the double bridge hydraulic network. The device will still achieve the effect of initial `slicing off` of excess sample from analytical site S, but once saturation occurs the bridge circuits will balance and the flow will continue such that reagents X and Y can be delivered to the analytical site without flow In channel I being distorted by that in channel J. Sample excess will again be retained in waste channels F and G and will therefore be unable to interfere in the process.
Whilst only the flow passing from A to F is needed to remove excess sample upstream of the analytical site (this being the excess contributing to inaccuracies in results), the flow passing from B to G across the interception area downstream of the analytical site is required to provide hydraulic balancing across the site and thus prevent any liquid flow from being diverted across the site.
As can be appreciated from the above, by appropriate design of the hydraulic circuit, balanced flows can be established once the excess sample has been sliced off and carried away from the analytical region, thus defining the correct sample volume.
EXAMPLES
Three specific examples of devices illustrative of the invention will now be described, for use in biochemical assay procedures.
Example 1
FIG. 4 shows an analytical device 20 in the form of a capillary flow circuit made from porous material, in this case Millipore AP25 filter paper. It may be used to indicate in a fixed area display the presence of pregnancy hormone HCG in a urine sample.
Liquid channels are formed by cutting or by wax printing impervious barriers. Channel 21 extends from a channel end 35 across a widened common flow region 33, and on to waste reservoir 24. The common flow region is connected to a source of liquid 22 through channel 26 via channel end 36. An analytical site 23 is located in the common flow region 33, in line with channel 21 and with the connection to waste reservoir 24. The common flow region 33 also includes channels 25 and 28 which can be connected to liquid source 22 via the channel 26. Channel 25 crosses and connects to channel 21 and terminates in waste reservoir 27. Channel 28 is also connected to channel 26, crosses and connects to channel 21, and terminates in a separate waste reservoir 29. An impermeable barrier 32 is provided in the form of a bar defining an obstacle between analytical site 23 and flow arriving at the common flow region 33 from channel 26.
Positioned on channel 21 is a zone of blue latex particles 30 which are coated with a second antibody to HCG, and which are free to be entrained and to move with liquid flow along the channel. Positioned at the analytical site 23 is a defined zone of a first antibody to HCG 31 which is immobilised to the porous material within a specific region as shown in FIG. 4a.
In use, a urine sample for analysis is applied at the analytical site 23 and HCG hormone present In the sample proceeds to bind to the immobilised first antibody. The sample volume is undefined at this stage and excess sample ingresses beyond the specific immobilised region 31 into excess regions 37 (FIG. 4b).
It Is important that the applied sample volume is chosen with respect to the thickness of the material of the device so that a volume of the sample to be defined is substantially uniformly distributed, at least within the material defined by zone 31. Furthermore, as a practical requirement of this and subsequent examples, the volume of applied sample must not be so great as to ingress beyond the capability of the volume definition means. For example excess sample volume 37 to the left of analytical site 23 must be less than the liquid capacity of reservoir 27. The device is then connected to the source of liquid 22 via the ends 35 and 36 of channels 21 and 26, as shown n FIG. 4b, and liquid begins to flow along these channels by capillary action. The lengths of channels are selected such that liquid flows up channel 26 and along channels 25 and 28 respectively, about each side of transverse bar 32 and analytical site 23, and washes excess urine sample into reservoirs 27 and 29 respectively, before liquid from channel 21 reaches the common flow region 33. This is shown in FIG. 4c, in which the whole common flow region has become saturated. Meanwhile, liquid continues to flow in channel 21 and opposing flows in this channel (shown by arrows) meet at the second antibody zone 30. Once saturated, all liquid in channel 21, including entrained blue latex particles coated with second antibody, begins to flow towards the analytical site 23 and waste reservoir 24. Liquid flow serves to wash any unbound sample 39 from the analytical site towards reservoir 24 (FIG. 4d) before the blue latex particles coated with second antibody 30 arrive at the analytical site 23. Any HCG antigen present in the sample, now bound to the first antibody 31 immobilised at the analytical site, binds to the blue latex particles thereby forming a visual indicator to display to the user an indication of the amount of HCG antigen present. Further liquid flow serves to wash unbound latex particles into reservoir 24 and thereby visually enhance any bound at the analytical site. Flow terminates when reservoir 24 is totally saturated.
After the sample volume has been defined as described above it is important to prevent flow arriving from channel 26 joining and distorting that in channel 21 travelling towards the analytical site 23. This is achieved by arranging the dimensions of channels 21, 25, 26 and 28 to form a hydraulic bridge circuit such that the bridge is balanced to attain zero flow along a stagnation line 38 (FIG. 4c). This design can be achieved by calculation, computer modelling or by iterative empirical determination.
As previously explained the sample excess waste reservoirs are designed so that waste products remain trapped therein, since it is important that these products do not interfere in subsequent stages of the process. To monitor this, `sample too large` or `sample too small` indicators can be provided. FIG. 4e shows a detail of the device of FIG. 4a contained within a housing P provided with two transparent windows W 1 and W 2 coincident with reservoir 27. If the sample is coloured (such as blood), then the appearance of the colour in one or both of the windows indicates the presence of the trapped excess sample. If the sample is colourless then a chemical, which produces a colorimetric reaction with the sample, can be incorporated into the waste reservoir. FIG. 4e shows a satisfactory result, with the steady state situation being the appearance of colour only in window W 2 . If the colour appears in neither window then this a `sample too small` indication, and if the colour appears in both windows W 1 and W 2 then this provides a `sample too large` indication. In either case the user is warned that the sample volume is inappropriate to perform an accurate test.
Example 2
FIG. 5 illustrates an analytical device 40 in the form of a capillary flow circuit constructed generally as described n example 1 but with a linear analogue display to indicate a quantifiable result. Its purpose is to quantify the amount of cholesterol present in a specimen of blood serum.
A channel 41 extends from an end 42 for liquid application through a widened common flow region 44 and to waste reservoir 43. A channel 45 extends from an end 46 to the common flow region 44 and separates into two channels 47 and 48 which connect to channel 41. A third channel 49 connects an end 50 to channel 41 midway between the points at which channels 47 and 48 connect to channel 41. Liquid impermeable bars 51, 52 and 53 are provided in common flow region 44. Parallel bars 51 and 52 between the points at which channels 45 and 49 connect with the common flow region 44 define a first immobilised region 54 therebetween and in this specific region, which corresponds to the sample site, a fixed volume of cholesterol esterase and cholesterol oxidase is immobilised onto the porous material. Located alongside liquid-impermeable bar 53 is an elongated second immobilised region 55 where horseradish peroxidase (HRP) on a colorimetric substrate is immobilised onto the porous material. Bar 53 separates the porous material into two parallel channels 41a and 41b, region 55 being in channel 41b, and the region lies in line with first immobilised region 54.
In use, an undefined volume of serum sample 56 Is applied at the first immobilised region and excess serum 57 ingresses beyond the boundaries of the region 54. The ends 42,46 and 50 of channels 41, 45 and 49 respectively are then simultaneously introduced to a liquid source 60 (FIG. 5b) and the liquid commences to flow in the channels. The combined length of channels 45 and 47, and that of channels 45 and 48, between channel end 46 and the first region 54, are chosen such that liquid flows about each side of the region 54 before liquid In channels 41 and 49 reaches the common flow region 44. This initial liquid flow washes excess serum 57 into channel 41, to the left of liquid impermeable bar 52 as shown In FIG. 5b. Meanwhile, liquid continues to flow n channels 41 and 49, and opposing flows eventually meet in these channels. During this time any cholesterol contained in the serum sample, the volume of which has now been automatically defined, reacts with the fixed volume of immobilised cholesterol esterase and cholesterol oxidase in first region 54, to produce an amount of hydrogen peroxide proportional to the amount of cholesterol present. The hydrogen peroxide then begins to flow upward carried by the liquid flow, thus terminating the first incubation stage. Providing the device is connected quickly to the liquid reservoir 60 after sample application, the incubaton stage producing hydrogen peroxide is timed automatically by the liquid travel time in the various channels.
A `slug` of hydrogen peroxide 62, proportional to the amount of cholesterol in the sample, then ascends channel 41b (FIG. 5c) and reacts with the HRP and the colorimetrc substrate at second immobilised region 55. This produces an insoluble coloured product 63, the reaction using up hydrogen peroxide as the latter ascends channel 41b such that a coloured line or bar s produced whose length is proportional to the amount of cholesterol in the serum sample (FIG. 5d). The user can read off the cholesterol level from a graduated scale on the device housing (not shown).
After the sample volume has been defined as described above it is important to prevent flow from the various channels distorting the `slug` of hydrogen peroxide and its ascent in channel 4lb. Once again, this is achieved by arranging the dimensions and positioning of the various channels to produce a balanced hydraulic circuit, such that when saturated there will be no flow between channels 41a and 41b. The slug will then travel straight into immobilised site 55, and the excess sample 57 will be washed straight up channel 41a and into the waste reservoir 43 (FIG. 5d).
Example 3
FIG. 6 shows an alternative analytical device 70, again taking the form of a capillary flow circuit in porous material. This example concerns once again a cholesterol assay and a linear analogue result, and uses the same chemistry as example 2 above, the device distinguishing itself in that it can be fabricated in a more compact form, using only two channels instead of three to connect to the liquid source.
Channel 71 extends from an end 72 to reservoir 73. Channel 74 extends from end 75 via channels 76 and 77 and connects to channel 71. Channel 71 is separated into channels 71a, 71b and 71c by parallel liquid impermeable bars made up of in line portions 78, 79, 80 and 81, 82 respectively, as can be seen in FIG. 6a. A first immobilised region 83, corresponding to the sample site, is located between bars 79 and 81 and defined by an area of cholesterol esterase and cholesterol oxidase. An area of immobilised HRP on a colorimetrtc substrate 84 makes up the second immobilised region which occupies a strip of material between bars 80 and 82, in channel 71b.
Once again in use an undefined volume of serum sample is applied at the first immobilised region, ingressing beyond the boundaries of the region to provide excess 85 in the surrounding channels (FIG. 6a).
The channel ends 72 and 75 are then connected to liquid source 90 (FIG. 6b). As liquid from channel 74 through channels 76 and 77 reaches the sample before that from channel 71, it flows around either side of impermeable bar 81 and washes excess serum 85 into channel 71 (FIG. 6b). Meanwhile, liquid continues to flow in channel 71 from channel end 72 and opposing flows meet as shown at 92 and 93, from where the liquid moves towards the immobilised regions and waste reservoir 73. In a similar manner to the operation of the device of Example 2, a `slug` of hydrogen peroxide 94 is produced at first region 83 and carried into second region 84 in channel 7lb, where it begins to react with the HRP and colorimetric substrate therein FIG. 6c). Again, a coloured bar 95 is produced whose length is proportional to the amount of cholesterol in the metered serum sample FIG. 6d).
After the sample volume has been defined it is important to prevent flow from entering or leaving the analytical channel 71bother than axially. This is achieved by arranging the geometry of the device to create a balanced hydraulic bridge circuit such that once saturated no flow occurs across connections 96 and 97 between channels (FIG. 6b).
Clearly, numerous other devices can be designed according to the invention for a wide variety of different analytical tests, in each case arranging that initial liquid flow automatically removes excess sample from around a defined reaction area, subsequent flow being such that this removed excess will not interfere with later stages of the analysis.
The invention may be used in conjunction with separation membranes such as plasma/red cell separation membranes as described in, e.g., Patent Specification U.S. Pat. No. 5,240,862. Such a membrane entraps red blood cells but allows plasma to pass.
The use of a separation membrane in a device according to the invention is illustrated in FIGS. 7a and 7b. In FIG. 7athe dominant flow of plasma is along the separation membrane 100, the whole blood being applied to a retention zone 101 arranged symmetrically to and adjacent to the plasma volume definition region 102. The dimensions of the retention zone are such that the red blood cells are retained within this zone, whilst the plasma can fill and extend beyond the plasma volume definition region 102, the volume to be determined by subsequent liquid flow according to the invention. In FIG. 7b the dominant flow of plasma is transverse to the plane of the separation membrane 110, in this case a separate membrane which overlies and extends beyond the plasma volume definition region 111.
Separation membranes such as X-flow PS21 are suitable for this application.
It is to be noted that each device preferably additionally comprises a housing around the porous material through which the sample can be applied, and may also additionally comprise a means of connecting the device to a liquid source, ensuring the liquid is applied to the extremity of each appropriate channel simultaneously.
To make the devices more compact, they need not be of planar form but may be folded or composed of multiple superposed layers forming the various channels, with cross connections provided between different layers.
The above examples use porous material suitable for capillary flow, such as filter paper. However the invention can also be applied in devices employing non-porous capillary action, such devices still providing hydraulic circuits which can be designed to produce the desired flow conditions when component channels are filled.
It will also be appreciated that the specific device embodiments and indeed other devices according to the invention are not intended to be limited to adaptation and use in diagnostic applications.
Embodiments of the invention illustrated in the accompanying Figures and described above are given by way of example only, and it should be understood that these in no way limit the scope of the invention, which is intended to embrace all embodiments falling within the spirit and scope of the appended claims. | Capillary flow liquid transfer device having first and second flow channels, the first leading from a first channel end to a volume determination site and the second flow channel leading from a second channel end and crossing the first channel in fluid connection therewith in an interception area bordering the volume determination site directly upstream thereof relative to the flow in the first channel. The liquid flow in the second channel reaches the interception area before that in the first channel upon simultaneous application of liquid from the liquid supply to the first and second channel ends such that excess substance is received in a waste reception area separate from substance received in the volume determination site. | 1 |
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to the German application No. 10 2004 014 712.4, filed Mar. 25, 2004 which is incorporated by reference herein in its entirety.
FIELD OF INVENTION
[0002] The present invention relates to a method for the enabling or blocking of an operating mode in a medical diagnostic device, in particular to image-generating diagnostics.
BACKGROUND OF INVENTION
[0003] Such a method is known from DE 102 20 348 A1. Whenever a user wishes to use a piece of medical equipment, a check is made as to whether the user is authorized to use said equipment and whether the costs incurred are to be paid before the use thereof. Use is automatically enabled if authorization still exists, and if no costs are outstanding. Alternatively, use is automatically blocked if authorization no longer exists, or if costs are still outstanding.
[0004] DE 101 55 092 A1 discloses a method for enabling an operational part of a computer software product and of installations pertaining thereto. As soon as a user wishes to use the operational part of the computer software product, a processor causes a transmitter to transmit a launch signal. It is only when a transponder receives this launch signal and thereupon transmits back an enabling code that the operational part of the computer software product is run.
SUMMARY OF INVENTION
[0005] In medical diagnostic devices, in particular for image-generating diagnostics, consumable materials are frequently used. These may be, for example, sedatives or contrast media. In particular, when using contrast media in image-generating diagnostics, for example in computer tomography scanners or magnetic resonance tomography scanners, correct use is necessary. Likewise the possibility should be excluded of a contrast medium or consumable material that is incompatible with the respective selected operating mode of the diagnostic device being used.
[0006] An object of the present invention is to provide a method by means of which the use in medical diagnostic devices of consumable materials that are not suitable for the respective operating mode is prevented.
[0007] The above object is achieved by the claims. The consumable materials required for an operating mode are provided with a machine-readable identification tag and are detected by a reading device. Then an enabling system connected to the reading device verifies that the consumable materials required have been detected correctly by interrogating a database connected thereto which stores corresponding information relating to the respective operating mode. It is only after successful verification of the consumable material that the enabling system releases the operating mode of the diagnostic device. If, for example, a user inadvertently attempts to use an incorrect contrast medium for an examination, this is detected by the enabling system and the respective operating mode is blocked. Unnecessary repeat examinations are thus avoided, which is an advantage in particular where there may be side effects of using consumable materials or of the examination itself, for example in computer tomography scanning.
[0008] In an advantageously designed method, each time the identity tag is read off, the reading device decreases a value on a counter located in the identification tag by a given value. Here the counter contains the possible number of applications for the respective pack of consumable material. The enabling system releases the operating mode of the diagnostic device only when the decrease on the counter has been successfully verified. As soon as the counter reaches a given value, the operating mode of the diagnostic device is blocked by the enabling system when the identification tag is read off by the reading device. This prevents, for example, a used bottle of contrast medium being filled with a contrast medium that does not correspond with the operating mode and being incorrectly used.
[0009] In an advantageously designed method, the enabling system releases the operating mode of the diagnostic device only after successful verification by the reading device of a particular manufacturer of the required consumable material. This has the advantage, in particular when using contrast media in image-generating diagnostics, that the same contrast medium from a particular manufacturer is always used and that no generic products of a different quality or composition come into use, in which case the parameters of the examination would have to be modified.
[0010] In an advantageously designed method, the use of the consumable material is transmitted by the enabling system to a storage device that is connected to the diagnostic device, such that the use can be stored in a patient-related manner. This has the advantage that the costs of medical diagnostic examination can be calculated in a patient-related manner. There is the additional advantage that the use of the consumable material is documented in a patient-related manner, which is particularly desirable where the consumable material has side effects.
[0011] In a further advantageously designed method, the database likewise stores advice on the use of the respective operating mode and in particular on the consumable material used. After the consumable material has been read in by the reading device, information on the use of the consumable material in the respective operating mode of the diagnostic device is requested from the database by the enabling system and displayed on a display medium together with advice relating to the use of the respective mode of operation. This minimizes the risk of incorrect operation by the user.
[0012] One embodiment of the method is advantageous in that a contactlessly readable transponder is read off by the reading device, as a result of which handling is facilitated.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Further advantages and details will become apparent from the description that follows of an embodiment, in conjunction with the drawings. The drawings show:
[0014] FIG. 1 : a diagram of the diagnostic device and
[0015] FIG. 2 : a flowchart showing the main process steps.
DETAILED DESCRIPTION OF INVENTION
[0016] The diagnostic device shown in diagram form in FIG. 1 comprises a diagnostic module 101 , which is connected to an enabling system 102 . The test control unit 103 is used to select an operating mode for the diagnostic device. A database 104 stores information relating to the respective mode of operation, which information is interrogated by the enabling system 102 . In particular, information relating to the consumable material required for the respective operating mode is interrogated and displayed on a display medium 105 . A reading device 106 that is connected to said enabling system comprises a transmitter and receiver unit 107 , which establishes a wireless communication 108 with a transponder 109 . The transponder 109 is affixed to a pack of consumable material, which here takes the form of a bottle of contrast medium 110 . In addition to an operating unit 111 and a transmitter and receiver unit 112 , the transponder 109 also contains a memory in the form of an EEPROM 113 . Said EEPROM 113 is both readable and writable by the operating unit 111 . Writing procedures, that is, changes to the EEPROM 113 are irreversible. The EEPROM 113 functions as a counter that stores the number of possible uses of the bottle of contrast medium 110 . In each read-off procedure, the operating unit 111 transmits the value stored in the EEPROM 113 to the reading device 106 and decreases the value stored in the EEPROM by “one”. A successful or unsuccessful decrease is likewise transmitted to the reading device 106 . The EEPROM 113 additionally contains information on the brand and “best before” date of the contrast medium. The above data are likewise transmitted to the reading device 106 . All the data transmitted by the transponder to the reading device 106 are further transmitted to the enabling system 102 , which decides from data whether it will enable or block the operating mode of the diagnostic device. If, for example, the “best before” date on the contrast medium has been exceeded, the operating mode of the diagnostic device is blocked. Likewise from a given value of the EEPROM 113 , preferably the value “zero”, the operating mode of the diagnostic device is blocked by the enabling system 102 and thus the bottle of contrast medium 110 cannot be used. As a result thereof, use of a bottle of contrast medium 110 filled with a potentially inferior generic product is prevented, for example. After successful verification by the reading device 106 , the enabling system 102 transmits the use of the consumable material to a connected memory unit 114 , wherein corresponding data are stored in a patient-related manner.
[0017] According to the method shown in FIG. 2 , the operating mode of the diagnostic device is selected in step 1 . Then in step 2 information from the database relating to the operating mode is interrogated and stored in the enabling system. Said information contains in particular the consumable material that is required for the respective mode of operation. In step 3 the user is prompted to determine, by means of the reading device, the consumable material that is required for the mode of operation. In step 4 a check is made as to whether the consumable material has been determined. If this is not the case, the user is again prompted to do so in step 3 . If the consumable material is detected, then a check is made in step 5 as to whether the correct consumable material has been detected. If this is not the case, in step 6 , the operating mode is blocked and the user is again prompted in step 1 to select a mode of operation. In three subsequent steps 7 , 8 and 9 , the manufacturer of the consumable material, the number of applications that can be carried out with the respective pack and the “best before” date are checked. If one of the checks 7 , 8 or 9 is unsuccessful, in step 6 the operating mode is blocked and the user is again prompted in step 1 to select an operating mode. Where there is a positive outcome for selection steps 7 , 8 and 9 , in the subsequent step 10 the number on the consumable material counter in the transponder is decreased by the value “one”. In step 11 the transponder subsequently provides notification as to whether the decrease in the number on the counter has been successfully achieved. In step 12 , the enabling system checks from the data transmitted by the transponder whether the decrease in the number on the counter was successful. If this is not the case, the operating mode is blocked in step 6 and the user is again prompted in step 1 to select an operating mode. In the case of a correct decrease in the number on the counter, in step 13 the advice relating to the use of the consumable material and operational mode that has been interrogated in the database is displayed on the display medium. The operating mode is then enabled in step 14 and the use of the consumable material is stored in step 15 at the same time as the patient-related documentation. | A method for the enabling or blocking of an operating mode in a medical diagnostic device enables the operating mode of the diagnostic device only after successful verification of the consumable material required for the operational mode. The consumable material is identified by a machine-readable identification tag, which is read off by a reading device. | 0 |
FIELD OF THE INVENTION
[0001] This invention relates, in general, to equipment utilized in conjunction with operations performed in subterranean wells and, in particular, to an apparatus and method for reaming a wellbore during the installation of a tubular string without rotating the tubular string.
BACKGROUND OF THE INVENTION
[0002] Without limiting the scope of the present invention, its background is described with reference to constructing a subterranean well including a liner string, as an example.
[0003] In conventional practice, the drilling of an oil or gas well involves creating a wellbore that traverses numerous subterranean formations. For a variety reasons, each of the formations through which the well passes is preferably sealed. For example, it is important to avoid an undesirable passage of formation fluids, gases or materials out of the formation and into the wellbore or for wellbore fluids to enter the formation. In addition, it is commonly desired to isolate producing formations from nonproducing formations to avoid contaminating one formation with the fluids from another formation.
[0004] To avoid these problems, conventional well architecture includes the installation of casing within the wellbore. In addition to providing the sealing function, the casing also provides wellbore stability to counteract the geomechanics of the formation such as compaction forces, seismic forces and tectonic forces, thereby preventing the collapse of the wellbore wall. In standard practice, each succeeding casing string placed in the wellbore has an outside diameter having a reduced size when compared to the previously installed casing string. Specifically, the wellbore is drilled in intervals whereby a casing, which is to be installed in a lower wellbore interval, must be passed through the previously installed casing string in an upper wellbore interval.
[0005] The casings are generally fixed within the wellbore by a cement layer between the outer wall of the casing and the wall of the wellbore. During the drilling of the wellbore, annuli are provided between the outer surfaces of the casings and the wellbore wall. When a casing string is located in its desired position in the well, a cement slurry is pumped via the interior of the casing, around the lower end of the casing and upwards into the annulus. As soon as the annulus around the casing is sufficiently filled with the cement slurry, the cement slurry is allowed to harden. The cement sets up in the annulus, supporting and positioning the casing and forming a substantially impermeable barrier which divides the wellbore into subterranean zones.
[0006] In one approach, each casing string extends downhole from the surface such that only a lower section of each casing string is adjacent to the wellbore wall. Alternatively, the wellbore casings may include one or more liner strings, which do not extend to the surface of the wellbore, but instead typically extend from near the downhole end of a previously installed casing downward into the uncased portion of the wellbore. Liner strings are typically lowered downhole on a work string that may include a drill pipe string and a running tool that attaches to the liner string. The liner string typically includes a liner hanger at its uphole end that may be mechanically or hydraulically set.
[0007] Preferably, the liner string is set or suspended by the liner hanger at a location in the wellbore so that the downhole end of the liner string extends to close proximity of the bottom of the wellbore. It has been found, however, that in certain wellbores such as deviated wellbores, horizontal wellbores, multilateral wellbores and the like, it is difficult to work the liner string to the bottom of the wellbore. For example, during drilling of the lowermost section of the wellbore and the installation of the liner string, debris may build up near the bottom of the wellbore, which prevents installation of the liner string at the desired depth. Attempts have been made to use a conventional reamer shoe at the lower end of the liner string such that rotation of the liner string will allow the cutting structure of the reamer shoe to penetrate through the debris. It has been found, however, that in certain deep wells including the aforementioned deviated wellbores, horizontal wellbores, multilateral wellbores and the like, the torque capacity of the drilling rig, the liner threads or both, limits the ability to rotate the liner string. Accordingly, a need has arisen for an apparatus and method for reaming a wellbore during the installation of a liner string without the requirement of rotating the liner string.
SUMMARY OF THE INVENTION
[0008] The present invention disclosed herein is directed to an apparatus for reaming a wellbore during the installation of a tubular string without rotating the tubular string. More specifically, the apparatus and method of the present invention utilize a reamer shoe that does not require rotation of the tubular string during installation but instead utilizes a rotatable sleeve to rotate the reamer shoe.
[0009] In one aspect, the present invention is directed to an apparatus for reaming a wellbore without rotating the tubular string that extends to the surface of the wellbore. The apparatus includes a mandrel that is coupled to the downhole end of the tubular string. A sleeve is operably associated with the mandrel such that longitudinal travel of the mandrel relative to the sleeve rotates the sleeve relative to the mandrel. A reamer shoe is coupled to a downhole end of the sleeve such that rotation of the sleeve rotates the reamer shoe.
[0010] In one embodiment, the tubular string may be a liner string, a casing string or the like. In another embodiment, the mandrel includes at least one groove, such as a plurality of spiral grooves or a J-slot, cut in a sidewall portion of the mandrel, such as the inner or outer surface of the mandrel. In this embodiment, a coupling device that is operably associated with the sleeve and extendable into the at least one groove translates the longitudinal travel of the mandrel relative to the sleeve into rotation of the sleeve and the reamer shoe relative to the mandrel. In certain embodiments, a biasing member may be used to urge the sleeve from a contracted position toward an extended position. In this embodiment, at least one of the mandrel and the sleeve may have at least one slot in a sidewall portion thereof. In another embodiment, the reamer shoe may include a cutting structure, at least one flow port or both.
[0011] In another aspect, the present invention is directed to an apparatus for reaming a wellbore. The apparatus includes a drill pipe string extendable to the surface of the wellbore. A liner string is coupled to the downhole end of the drill pipe string. A mandrel is coupled to the downhole end of the liner string. The mandrel includes at least one groove cut in an outer surface of a sidewall portion thereof. A sleeve is at least partially position about the exterior of the mandrel such that longitudinal travel of the mandrel relative to the sleeve shifts the sleeve between an extended position and a contracted position relative to the mandrel. A reamer shoe is coupled to the downhole end of the sleeve. At least one coupling device is operably associated with the sleeve and extendable into the at least one groove such that the longitudinal travel of the mandrel relative to the sleeve caused the sleeve to rotate relative to the mandrel, thereby rotating the reamer shoe.
[0012] In another aspect, the present invention is directed to a method for reaming a wellbore. The method includes coupling a reamer assembly to a tubular string, the reamer assembly includes a mandrel, a sleeve operably associated with the mandrel and a reamer shoe coupled to the sleeve, running the tubular string into the wellbore until the reamer shoe contacts a restriction in the wellbore, applying weight on the reamer shoe via the tubular string, longitudinally contracting the reamer assembly to rotate the sleeve relative to the mandrel, thereby rotating the reamer shoe, reducing the weight applied to the reamer shoe and longitudinally extending the reamer assembly.
[0013] The method may also include coupling the reamer assembly to a liner string, a casing string or the like, sliding a coupling device operably associated with the sleeve in a groove cut in a surface of the mandrel, sliding the coupling device in the groove cut in an outer surface of the mandrel, urging the sleeve toward the extended position of the reamer assembly with a biasing member and urging the sleeve toward the extended position of the reamer assembly by pumping a fluid through at least one flow port of the reamer shoe.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] For a more complete understanding of the features and advantages of the present invention, reference is now made to the detailed description of the invention along with the accompanying figures in which corresponding numerals in the different figures refer to corresponding parts and in which:
[0015] FIG. 1 is a schematic illustration of an offshore oil and gas platform operating an apparatus for reaming a wellbore according to an embodiment of the present invention;
[0016] FIG. 2 is a side view of a reamer assembly in its extended configuration for use in an apparatus for reaming a wellbore according to an embodiment of the present invention;
[0017] FIG. 3 is a top view of a reaming bit for use in an apparatus for reaming a wellbore according to an embodiment of the present invention;
[0018] FIG. 4 is a side view of the reamer assembly of FIG. 2 in its contracted configuration;
[0019] FIG. 5 is a side view of a reamer assembly for use in an apparatus for reaming a wellbore according to an embodiment of the present invention;
[0020] FIG. 6 is a side view, partially cut away, of a reamer assembly for use in an apparatus for reaming a wellbore according to an embodiment of the present invention; and
[0021] FIG. 7 is a side view, partially cut away, of a reamer assembly for use in an apparatus for reaming a wellbore according to an embodiment of the present invention;
[0022] FIG. 8 is a side view, partially cut away, of a reamer assembly for use in an apparatus for reaming a wellbore according to an embodiment of the present invention; and
[0023] FIG. 9 is a side view of a reamer assembly for use in an apparatus for reaming a wellbore according to an embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0024] While the making and using of various embodiments of the present invention are discussed in detail below, it should be appreciated that the present invention provides many applicable inventive concepts, which can be embodied in a wide variety of specific contexts. The specific embodiments discussed herein are merely illustrative of specific ways to make and use the invention, and do not delimit the scope of the invention.
[0025] Referring initially to FIG. 1 , an apparatus for reaming a wellbore being deployed from an offshore platform is schematically illustrated and generally designated 10 . A semi-submersible platform 12 is centered over submerged oil and gas formation 14 located below sea floor 16 . A subsea conduit 18 extends from deck 20 of platform 12 to wellhead installation 22 , including blowout preventers 24 . Platform 12 has a hoisting apparatus 26 , a derrick 28 , a travel block 30 , a hook 32 and a swivel 34 for raising and lowering pipe strings, such as a liner string 36 .
[0026] A wellbore 38 extends through the various earth strata including formation 14 . An upper portion of wellbore 38 includes casing 40 that is cemented within wellbore 38 by cement 42 . Disposed within the lower portion of wellbore 38 is liner string 36 . Liner string 36 is being lowered downhole on a work string 44 that includes a setting tool 46 that attaches work string 44 to liner string 36 . Preferably, the upper portion of work string 44 is formed from a drill pipe string or similar tubular members. Liner string 36 includes a liner hanger 48 at its uphole end that is operable to be set by setting tool 46 .
[0027] A reamer assembly 50 is coupled to the downhole end of liner string 36 . As shown, liner string 36 has been run in wellbore 38 to a position in which reamer assembly 50 has come in contact with debris 52 which has built up in the bottom of wellbore 38 . This debris 52 makes it difficult to work liner string 36 to its desired location proximate the bottom of wellbore 38 . Use of the present invention, however, enables liner string 36 to be positioned as desired. Specifically, reamer assembly 50 is used to clear debris 52 from the bottom of wellbore 38 . Reamer assembly 50 is operated without the need to provide torque from the surface via rotating working string 44 and liner string 36 . Instead, reamer assembly 50 of the present invention is rotatable responsive to the application of a compressive force applied to reamer assembly 50 . This compressive force may be delivered via the application of a longitudinal force in the downhole direction from the surface via liner string 36 and work string 44 to operate reamer assembly 50 of the present invention as described in greater detail below.
[0028] Even though FIG. 1 depicts a deviated wellbore, it should be understood by those skilled in the art that the apparatus for reaming a wellbore of the present invention is equally well suited for use in wellbores having other directional orientations including vertical wellbores, horizontal wellbores, multilateral wellbores or the like. Accordingly, it should be understood by those skilled in the art that the use of directional terms such as above, below, upper, lower, upward, downward, uphole, downhole and the like are used in relation to the illustrative embodiments as they are depicted in the figures, the uphole direction being toward the top or the left of the corresponding figure and the downhole direction being toward the bottom or the right of the corresponding figure. Also, even though FIG. 1 depicts an offshore operation, it should be understood by those skilled in the art that the apparatus for reaming a wellbore of the present invention is equally well suited for use in onshore operations.
[0029] Referring next to FIG. 2 , therein is depicted a reamer assembly 100 for use in an apparatus for reaming a wellbore according to the present invention. Reamer assembly 100 is used to clear the bottom of a wellbore of debris or open a restriction encountered during the installation of a tubular string such as a casing string or liner string in a wellbore that has been previously drilled. Reamer assembly 100 includes a mandrel 102 that preferably includes a box end 104 for threadably coupling mandrel 102 with the lower end of a tubular string. In the illustrated embodiment, mandrel 102 includes a radially expanded section 106 that defines a shoulder 108 . As illustrated, mandrel 102 has four spiral grooves 110 forming a plurality of turns around the outer surface of mandrel 102 . Preferably, spiral grooves 110 take the form of helical curves. Even though reamer assembly 100 has be depicted as having a mandrel with four spiral grooves, it should be understood by those skilled in the art that reamer assembly 100 could alternatively have a mandrel with a greater number or lesser number of spiral grooves including a single spiral groove. In addition, even though reamer assembly 100 has be depicted as having a mandrel with spiral grooves formed in the outer surface, it should be understood by those skilled in the art that reamer assembly 100 could alternatively have a mandrel with spiral grooves formed in the inner surface.
[0030] Reamer assembly 100 includes a sleeve 112 . In the illustrated embodiment, sleeve 112 is partially positioned around mandrel 102 and is sized such that mandrel 102 can move longitudinally within sleeve 112 . In other embodiments, such as those embodiments in which the spiral grooves are formed in the inner surface of mandrel 102 , sleeve 112 could alternative be positioned partially within mandrel 102 and sized such that mandrel 102 could move longitudinally along the exterior of sleeve 112 . Sleeve 112 has a plurality of openings 114 that are preferably threaded. A pin 116 is securably received within each of the openings 114 such that pins 116 extend into spiral grooves 110 to secure sleeve 112 and mandrel 102 together. At its upper end, sleeve 112 defines a shoulder 118 . Preferably, sleeve 112 has a box end 120 for threadably coupling sleeve 112 with the upper end of a reamer shoe 122 . Positioned around mandrel 102 and between shoulder 108 of mandrel 102 and shoulder 118 of sleeve 112 is a biasing member depicted as a spiral wound compression spring 132 that urges sleeve 102 in the downhole direction away from radially expanded section 106 of mandrel 102 . Even though a particular type of biasing member has been depicted and described, those skilled in the art will recognize that other types of biasing members, such as wave springs, spring stacks and the like could alternatively be used in conjunction with the present invention.
[0031] As best seen in FIG. 3 , reamer shoe 122 has a cutting structure 124 that preferably includes a plurality of inserts 126 such as tungsten carbide inserts, polycrystalline diamond compact inserts or the like. As illustrated, inserts 126 are positioned on the leading edges of a plurality of reaming blades 128 such that inserts 126 will contact not only the bottom of the wellbore or restriction in the wellbore but also the sides of the wellbore during rotation of reamer shoe 122 . Reamer shoe 122 includes a plurality of flow ports that are depicted as nozzles 130 . Even though a particular type of reamer shoe has been depicted and described, those skilled in the art will recognize that other types of reamer shoes having cutting structures that are operable to ream a wellbore when rotated could alternatively be used in conjunction with the present invention.
[0032] In operation, reamer assembly 100 is coupled to the lower end of a tubular string such as a liner string, a casing string or the like and is run downhole until, for example, reamer shoe 122 contacts debris or a restriction in the wellbore. At this point, the operator can apply weight on reamer shoe 122 via the tubular string. The applied weight creates a compressive force within reamer assembly 100 . The compressive force within reamer assembly 100 causes mandrel 102 to longitudinally move within sleeve 112 , which contracts reamer assembly 100 , as best seen in FIG. 4 . Due to the pin 116 and groove 110 coupling of sleeve 112 and mandrel 102 , this longitudinal movement of mandrel 102 relative to sleeve 112 causes sleeve 112 to rotate relative to mandrel 102 . As reamer shoe 122 is securably coupled to sleeve 112 , this rotation of sleeve 112 causes reamer shoe 122 to rotate, thereby reaming the wellbore. Preferably, fluid is circulated from the surface through the tubular string and reamer assembly 100 such that the fluid is injected out of reamer shoe 122 via nozzles 130 . The fluid then carries the cutting to the surface by traveling up through the annulus surrounding the tubular string.
[0033] The process of rotating reamer shoe 122 can be repeated as necessary such that the tubular string may be positioned in the wellbore as desired. Specifically, by slacking off on the weight being applied to reamer shoe 122 , the tensile force generated by spring 132 as well as the downhole force generated by the pressure drop of fluids travel through nozzles 130 , during pumping operations, will urge sleeve 112 to travel longitudinally relative to mandrel 102 and return reamer assembly 100 to the position depicted in FIG. 2 . Thereafter, repeated cycles of weight on reamer shoe 122 will rotate reamer shoe 122 as required.
[0034] Referring next to FIG. 5 , therein is depicted a reamer assembly 200 for use in an apparatus for reaming a wellbore according to the present invention. Reamer assembly 200 includes a mandrel 202 that preferably includes a box end 204 for threadably coupling mandrel 202 with the lower end of a tubular string. As illustrated, mandrel 202 has four spiral grooves 210 forming a plurality of turns around the outer surface of mandrel 202 . Reamer assembly 200 includes a sleeve 212 . In the illustrated embodiment, sleeve 212 is partially positioned around mandrel 202 and is sized such that mandrel 202 can move longitudinally within sleeve 212 . Sleeve 212 has a plurality of openings 214 that are preferably threaded. A pin 216 is securably received within each of the openings 214 such that pins 216 extend into spiral grooves 210 to secure sleeve 212 and mandrel 202 together. Preferably, sleeve 212 has a box end 220 for threadably coupling sleeve 212 with the upper end of a reamer shoe 222 that includes a cutting structure 224 and a plurality of flow ports (not pictured).
[0035] In operation, reamer assembly 200 is coupled to the lower end of a tubular string and is run downhole until, for example, reamer shoe 222 contacts debris or a restriction in the wellbore. At this point, the operator can apply weight on reamer shoe 222 via the tubular string. The applied weight creates a compressive force within reamer assembly 200 . The compressive force within reamer assembly 200 causes mandrel 202 to longitudinally move within sleeve 212 , which contracts reamer assembly 200 . Due to the pin 216 and groove 210 coupling of sleeve 212 and mandrel 202 , this longitudinal movement of mandrel 202 relative to sleeve 212 causes sleeve 212 and reamer shoe 222 to rotate relative to mandrel 202 , thereby reaming the wellbore. A fluid is circulated from the surface through the tubular string and reamer assembly 200 such that the fluid is injected out of reamer shoe 222 via the nozzles to carry cutting to the surface. The process of rotating reamer shoe 222 can be repeated as necessary by slacking off on the weight being applied to reamer shoe 222 which allows the downhole force generated by the pressure drop of fluids travel through the nozzles to extend sleeve 212 relative to mandrel 202 .
[0036] Referring next to FIG. 6 , therein is depicted a reamer assembly 300 for use in an apparatus for reaming a wellbore according to the present invention. Reamer assembly 300 includes a mandrel 302 that preferably includes a box end 304 for threadably coupling mandrel 302 with the lower end of a tubular string. As illustrated, mandrel 302 has four spiral grooves 310 forming a plurality of turns around the outer surface of mandrel 302 . Reamer assembly 300 includes an outer shroud 306 that is securably coupled to or integral with mandrel 302 . Outer shroud 306 includes a shoulder 308 . Reamer assembly 300 also includes a sleeve 312 . In the illustrated embodiment, sleeve 312 is partially positioned around mandrel 302 and is sized such that mandrel 302 can move longitudinally within sleeve 312 . Sleeve 212 has a plurality of openings 314 that are preferably threaded. A pin 316 is securably received within each of the openings 314 such that pins 316 extend into spiral grooves 310 to secure sleeve 312 and mandrel 302 together. Preferably, sleeve 312 has a box end 320 for threadably coupling sleeve 312 with the upper end of a reamer shoe 322 that includes a cutting structure 324 and a plurality of flow ports (not pictured). Sleeve 312 includes a shoulder 318 . A spring 332 is positioned around mandrel 302 , between shoulder 308 and shoulder 318 . Shroud 306 protects spring 332 from damage during installation and operation of reamer assembly 300 . Reamer assembly 300 operates substantially similar to reamer assembly 100 described above.
[0037] Referring next to FIG. 7 , therein is depicted a reamer assembly 400 for use in an apparatus for reaming a wellbore according to the present invention. Reamer assembly 400 includes a mandrel 402 that preferably includes a box end 404 for threadably coupling mandrel 402 with the lower end of a tubular string. As illustrated, mandrel 402 has four spiral grooves 410 forming a plurality of turns around the outer surface of mandrel 402 . Mandrel 402 includes a radially expanded section 406 that defines a shoulder 408 . Reamer assembly 400 includes a sleeve 412 . In the illustrated embodiment, sleeve 412 is partially positioned around mandrel 402 and is sized such that mandrel 402 can move longitudinally within sleeve 412 . Sleeve 412 has a plurality of openings 414 that are preferably threaded. A pin 416 is securably received within each of the openings 414 such that pins 416 extend into spiral grooves 410 to secure sleeve 412 and mandrel 402 together. Preferably, sleeve 412 has a box end 420 for threadably coupling sleeve 412 with the upper end of a reamer shoe 422 that includes a cutting structure 424 and a plurality of flow ports (not pictured). Sleeve 412 includes a shoulder 418 . A spring 432 is positioned around mandrel 402 , between shoulder 408 and shoulder 418 . Reamer assembly 400 includes an outer shroud 434 that is securably coupled to or integral with sleeve 412 . Shroud 434 includes one or more slots 436 . Shroud 434 protects spring 432 from damage during installation and operation of reamer assembly 400 and slots 436 allow fluid to flow around spring 432 to keep this area free from debris. Reamer assembly 400 operates substantially similar to reamer assembly 100 described above.
[0038] Referring next to FIG. 8 , therein is depicted a reamer assembly 500 for use in an apparatus for reaming a wellbore according to the present invention. Reamer assembly 500 includes a mandrel 502 that preferably includes a box end 504 for threadably coupling mandrel 502 with the lower end of a tubular string. Mandrel 502 includes a radially expanded section 506 that defines a shoulder 508 . As illustrated, mandrel 502 has four spiral grooves 510 forming a plurality of turns around the outer surface of mandrel 502 . Mandrel 502 has one or more slots 536 . Reamer assembly 500 includes a sleeve 512 . In the illustrated embodiment, sleeve 512 is partially positioned around mandrel 502 and is sized such that mandrel 502 can move longitudinally within sleeve 512 . Sleeve 512 has a plurality of openings 514 that are preferably threaded. A pin 516 is securably received within each of the openings 514 such that pins 516 extend into spiral grooves 510 to secure sleeve 512 and mandrel 502 together. Preferably, sleeve 512 has a box end 520 for threadably coupling sleeve 512 with the upper end of a reamer shoe 522 that includes a cutting structure 524 and a plurality of flow ports (not pictured). Sleeve 512 includes a shoulder 518 . A spring 532 is positioned around mandrel 502 , between shoulder 508 and shoulder 518 . Reamer assembly 500 includes an outer shroud 534 that is securably coupled to or integral with sleeve 512 . Shroud 534 protects spring 532 from damage during installation and operation of reamer assembly 500 and slots 536 of mandrel 502 allow fluid to flow around spring 532 to keep this area free from debris. Reamer assembly 500 operates substantially similar to reamer assembly 100 described above.
[0039] Referring next to FIG. 9 , therein is depicted a reamer assembly 600 for use in an apparatus for reaming a wellbore according to the present invention. Reamer assembly 600 includes a mandrel 602 that preferably includes a box end 604 for threadably coupling mandrel 602 with the lower end of a tubular string. Mandrel 602 includes a radially expanded section 606 that defines a shoulder 608 . As illustrated, mandrel 602 has a single continuous groove depicted as a J-slot 610 forming a plurality of turns around the outer surface of mandrel 602 . Reamer assembly 600 includes a sleeve 612 . In the illustrated embodiment, sleeve 612 is partially positioned around mandrel 602 and is sized such that mandrel 602 can move longitudinally within sleeve 612 . Sleeve 612 has a plurality of openings 614 that are preferably threaded. A pin 616 is securably received within each of the openings 614 such that pins 616 extend into J-slot 610 to secure sleeve 612 and mandrel 602 together. Preferably, sleeve 612 has a box end 620 for threadably coupling sleeve 612 with the upper end of a reamer shoe 622 that includes a cutting structure 624 and a plurality of flow ports (not pictured). Sleeve 612 includes a shoulder 618 . A spring 632 is positioned around mandrel 602 , between shoulder 608 and shoulder 618 . Reamer assembly 600 operates substantially similar to reamer assembly 100 described above except that sleeve 612 and therefore reamer shoe 622 rotate to the right as reamer assembly 600 is compressed but do not counter rotate on the reverse stroke as pins 616 travel in the longitudinal portions of J-slot 610 .
[0040] While this invention has been described with reference to illustrative embodiments, this description is not intended to be construed in a limiting sense. Various modifications and combinations of the illustrative embodiments as well as other embodiments of the invention will be apparent to persons skilled in the art upon reference to the description. It is, therefore, intended that the appended claims encompass any such modifications or embodiments. | An apparatus for reaming a wellbore without rotating a tubular string that is extendable to a surface. A mandrel ( 102 ) is coupled to a downhole end of the tubular string. The mandrel ( 102 ) has at least one groove ( 110 ) in a sidewall portion thereof. A sleeve ( 112 ) is operably associated with the mandrel ( 102 ) such that longitudinal travel of the mandrel ( 102 ) relative to the sleeve ( 112 ) shifts the sleeve ( 112 ) between extended and contracted positions relative to the mandrel ( 102 ). A reamer shoe ( 122 ) is coupled to a downhole end of the sleeve ( 112 ). At least one coupling device ( 116 ) is operably associated with the sleeve ( 112 ) and extendable into the at least one groove ( 110 ) such that longitudinal travel of the mandrel ( 102 ) relative to the sleeve ( 112 ) caused the sleeve ( 112 ) to rotate relative to the mandrel ( 102 ), thereby rotating the reamer shoe ( 122 ). | 4 |
BACKGROUND AND SUMMARY OF THE INVENTION
The present invention relates to chokes or starting aids for small internal combustion engines and more particularly, to a choke or starting aid which is responsive to the vibration of the internal combustion engine upon start-up of the engine.
When starting small internal combustion engines, it is usually necessary to pull on the starter rope several times before the engine kicks over and begins to run. Generally, after a couple of pulls on the starter rope the engine starts and runs for a short period of time and then stops. This is what is commonly known in the field as a "false start". This "false start" phenomenon has been present in the chain saw art for several years and has come to be accepted by the users of such saws as an acceptable starting method. The user generally has knowledge of the fuel system procedure and understands why the system is not starting.
The difficulty in starting a cold small internal combustion engine centers around the choke system of these particular engines. When the choke system is in a closed position, the fuel line system of the cold engine has a very high restriction in the air intake. This restriction of the air intake forms a vacuum in the fuel line, sucking fuel into the engine via the carburetor from the fuel tank. As the starting rope is pulled, the engine sucks fuel into the carburetor by the vacuum created in the system. As the engine begins to fire, a certain amount of air is necessary to keep the engine running. With a manual choke, the user must open the choke quickly after the engine begins running or the user will experience the "false start" phenomenon. The reason for the "false start" is that as the speed of the engine increases, the engine sucks more fuel. With the choke in a closed position however, the amount of air flow entering the engine is not increased. Thus, a proper mixture of air and fuel is not achieved and the engine dies instantly. Also, if the engine does not start up, a substantial amount of fuel is sucked into the engine, via the carburetor causing the engine and carburetor to become flooded, further hampering the starting procedure of the engine.
Choke devices presently used in the field are of the butterfly type. These types of chokes are pivotally secured in the carburetor air port of an internal combustion engine. The choke usually pivots about a central axis, flipping from a closed to an open position. This type of choke assembly has several disadvantages. The choke is either in a fully closed or a fully open position. When starting the engine the choke is in the fully closed position. Once the engine starts, it is nearly impossible to rotate the choke to its open position, so that the engine will continue to run. Also, the butterfly valve may slip from a closed to an open position without notice to the user. This slippage is due to the fact that, in many instances, there is no resistance member holding the butterfly valve in position. Those skilled in the art are aware of yet other disadvantages of this type of choke assembly.
Accordingly, it is an object of the present invention to overcome the disadvantages of the above art. The present invention provides the art with a new and improved choke assembly which enables air to automatically enter the carburetor during the start-up of an internal combustion engine for providing a continuous running situation. The present invention includes a resilient biasing member for securing the choke assembly in place against slippage. Further, the present invention utilizes the vibration of the small internal combustion engine during start-up for enabling air to enter into the carburetor of the engine at start-up.
The new and improved choke assembly of the present invention provides the art with a semi-automatic choke or starting aid. The choke assembly generally is for small internal combustion engines having a carburetor with an air port in communication with the carburetor and combustion air. Also, a bore, through the carburetor, is in communication with the piston cylinder of the internal combustion engine. The choke of the present invention includes a mechanism for controlling an amount of combustion air entering the carburetor. The mechanism includes an inertia valve member positioned in the inlet air manifold for selectively controlling the amount of combustion air entering into the carburetor. A resilient biasing member, secured in the inlet air manifold, resiliently secures the inertia valve member in the inlet air manifold. The inertia vlave member and biasing member are responsive to the vibration of the internal combustion engine for controlling the amount of combustion air entering into the carburetor.
Generally, the inlet air manifold is coupled with a seating member which provides a seating surface for the interia valve in the manifold. The seating member has an aperture for metering the amount of air which enters into the carburetor. Also, the aperture provides the seating surface for the inertia valve member.
From the subsequent description and the appended claims taken in conjunction with the accompanying drawings, other objects and advantages of the present invention will become apparent to one skilled in the art.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross-sectional view of a small internal combustion engine having a choke or starting aid in accordance with the present invention.
FIG. 2 is an enlarged view of the choke or starting aid of FIG. 1.
FIG. 3 is a cross-sectional view similar to FIG. 2 of an alternative embodiment of a choke or starting aid in accordance with the present invention.
FIG. 4 is a cross-sectional view similar to FIG. 2 of an alternative embodiment of a choke or starting aid in accordance with the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIGS. 1 and 2, a choke assembly or starting aid is shown and is designated with the reference numeral 10. As best seen in FIG. 1, the choke assembly 10 is coupled with an internal combustion engine 12. The internal combustion engine 12 includes a crankshaft 14 having a piston rod 16 secured to it. The piston rod 16 has a piston head 18 which is slidably positioned in a piston cylinder 20 in the internal combustion engine 12. A carburetor 22, coupled with the internal combustion engine 12, is in communication with the piston cylinder 20 via a carburetor bore 24. The carburetor 22 provides a combustionable air/fuel mixture to the piston cylinder 20 for driving the internal combustion engine 12. The carburetor 22 is in communication with an inlet air manifold 26 which, in turn, is in communication with a source of combustion air, preferably atmospheric air. The choke assembly 10 is generally positioned in the inlet air manifold 26 of the carburetor 22 of the internal combustion engine 12, as best seen in FIGS. 1 and 2.
The carburetor 22 generally has a fuel inlet port 28 for providing fuel to the piston cylinder 20 for combustion in the piston cylinder 20. The carburetor 22 also has a throttle valve 30 for controlling the amount of air/fuel mixture which enters into the piston cylinder 20. The throttle valve 30 is pivotally positioned in the carburetor bore 24. A venturi 32 is formed in the carburetor bore 24 for enabling the air/fuel mixture to move more rapidly into the piston cylinder 20.
The inlet air manifold 26 is generally adjacent to and in communication with the carburetor bore 24. Combustion air is drawn through the inlet air manifold 26 for supplying combustion air into the piston cylinder 20 via the carburetor 22. Generally, the inlet air manifold 26 is formed of a projecting member 34 which is secured to the carburetor 22 by conventional means. The projecting member 34 has a bore 36 through the projecting member 34 enabling air to pass through the inlet air manifold 26. The projecting member 34 includes a continuous wall 38 defining the bore 36. The wall 38 has at least one, preferably two or more, apertures 40 and 42 in the wall 38 in communication with the bore 36. The apertures 40 and 42 enable combustion air to enter the carburetor 22, while bypassing the choke assembly 10, when the internal combustion engine is beyond the start-up condition.
The choke assembly 10 includes an inertia valve member 44 positioned in the inlet air manifold 26, a biasing member 46 securing the inertia valve member 44 in the inlet air manifold 26, a retaining member 48 for retaining the biasing member 46 in the inlet air manifold 26, and a manually rotatable seating member 50 for seating the interia valve member 44 in the inlet air manifold 26.
The interia valve member 44 is preferably a spherical member secured in the inlet air manifold 26 by the biasing member 46. The valve member 44, however, can be of any geometry with a mass or weight which reacts to vibration. The inertia valve member 44 responds to the vibration of the internal combustion engine 12. The valve member 44 vibrates off of the seat member 50 during start-up to enable combustion air to enter into the inlet air manifold 26 and provide a controlled amount of combustion air at start-up.
The biasing member 46 is preferably a helical spring. The biasing member 46 has a diameter such that the spherical inertia valve member 44 seats on one end of the biasing member 46. A spring constant is predetermined for the biasing member 46 so that when the internal combustion engine 12 is started the vibration of the engine 12 enables the biasing member 46 to compress enabling the inertia valve 44 to move away from the seat member 50 permitting air to enter into the inlet air manifold 26. The predetermined spring constant of the biasing member 46 also enables the biasing member 46, in a resting position, to firmly seat the inertia valve member 44 against the seat member 50.
The retaining member 48 preferably has a projecting member 52 for securing one end of the biasing member 46 onto the retaining member 48. The projecting member 52 has an aperture 55 through it for allowing combustion air to pass through the retaining member 48. The retaining member 48 is positioned in a groove 54 in the bore 36 of the wall 38 of the projecting member 34 for securing the retaining member 48 in the bore 36 of the projection member 34. The retaining member 46 also includes a plurality of apertures 56 and 59 about its projecting member 52 and flange portion 57 for enabling air to pass through the retaining member 48.
A foam filter 25 is positioned adjacent to the retaining member 48. The filter 25 traps and prevents inpurities in the combustion air from entering into the carburetor 22. The filter 25 may be removed and cleaned or replaced as needed.
The seating member 50 generally has a planar surface 58 covering the free depending end of the projecting member 34. The planar member 58 has an aperture 60 through it for seating the inertia valve member 44 in the aperture 60. The seating member 50 has a continuous wall 62 depending from the planar member 58 which surrounds a portion of projecting member 34. The seating member 50 has an overall cap shape. The depending wall 62 has at least one aperture 64, and preferably two or more apertures, for aligning with apertures 40 and 42 when seating member 50 is positioned in the open-choke position for enabling air to bypass the inertia valve member 44 when the internal combustion engine 12 is beyond the start-up condition. This alignment provides the choke assembly 10 with an open position which enables combustion air to bypass the inertia valve member 44.
FIG. 3 illustrates a second embodiment of the present invention. The previously discussed elements that are common between the disclosed embodiment will be designated with the same reference numerals.
FIG. 3 shows the projecting member 34. The wall 38 of the projecting member 34 has a flange 80 extending into the bore 36 and defining an aperture 82. The aperture 82 functions the same as the seating aperture 60 as described herein. Also, a pair of apertures 84 and 86 are in the flange 80. The apertures 84 and 86 function the same as apertures 40 and 42 as described herein.
A seating member 90 having an annular shaped planar body 92 is rotatably secured to the flange 80 via an annular element 93 which is nonrotatably secured to the flange 80 by a conventional fastening means. The body 92 has an aperture 94 aligned with aperture 82 for enabling combustion air to enter into the carburetor during start-up. The body 92 has a pair of smaller apertures 96 and 98, which function the same as apertures 64 and 65 described herein, which align with apertures 84 and 86 for enabling combustion air to bypass the inertia valve 44 when the choke assembly is in an off position. The body 92 has at least one projecting tab 100 for providing a means for easy rotation of the seating member 90. When the seating member 90 is rotated so that apertures 96 and 98 are not in alignment with apertures 84 and 86 the choke assembly is in a closed position. The function of the choke assembly is the same as that disclosed herein for the other embodiment of the present invention.
FIG. 4 illustrates another embodiment of the present invention. The previously discussed elements that are common between the disclosed embodiment will be designated with the same reference numerals.
FIG. 4 shows the projecting member 34 wherein the wall 38 of the projecting member 34 has a continuous top wall 120 having a series of apertures 122. A choke lever 124 is rotatably secured to the top wall 120 to rotate around a pin 125 secured to the top wall 120. The choke lever 124 has at least one aperture 126. Apertures 122 and 126 function the same as apertures 40 and 42, and 64 and 65, respectively, as described herein. The choke lever 124 rotates from an open position as shown, where apertures 122 and 126 are in alignment, to a closed position, not shown, when apertures 122 and 126 are not in alignment.
A foam air filter 25 is positioned in the bore 36 adjacent the top wall 120 by a plurality of ribs 127 and 128. A pair of inertia valve members 132 and 134 are seated on apertures 136 and 138, respectively, in the wall 38 of the projecting member 34. A spring biasing member 140 is positioned between the inertia valve members 132 and 134 for seating the members 132 and 134 in the apertures 136 and 138. The apertures 136 and 138 function the same as seating aperture 60 as described herein. An elongated housing 142 shaped like a tube cut in half axially along its centerline encapsulates the members 132 and 134 and spring biasing member 140 to retain the member 132, 134, and 140 in a proper relative position within the bore 36. The housing 142 is held in place by suitable means, such as by ribs 144. The choke assembly functions in the same general manner as that disclosed herein for the other embodiments of the present invention as described above.
As seen in FIG. 1, the fuel inlet port 28 of each embodiment is coupled with a fuel line 29 which, in turn, is coupled with a fuel tank 31. The fuel tank 31 has a rotatable removable cap 33. As an optional feature, the cap 33 has a primer bulb 35 positioned on the cap 33. The primer bulk 35 is coupled with a one way check valve 37 for enabling air to enter and remain in the fuel tank 31. When the primer bulb 35 is pushed several times against the one way valve 37, air can enter the fuel tank 31 to create a positive pressure in the fuel tank 31.
The disclosed choke assembly works as follows. The apertures 64 and 65 of the seating member 50 are rotated so that the apertures 64 and 65 are not in alignment with the apertures 40 and 42 of the projecting member 34. The inertia valve member 44 is seated in the aperture 62 of the seating member 50. The choke assembly 10 is now in its closed position.
The cold internal combustion engine 12 is started as follows. The choke is positioned in its closed position and the starting rope is pulled to cause the fuel to be sucked through the carburetor 22 due to the vacuum created in the fuel line by the closing of the choke assembly 10. Fuel is sucked through the carburetor 22 into the piston cylinder 20. The pulling on the starter rope causes the piston to begin its upstroke which, in turn, causes the piston to fire. As the piston 30 begins to fire, more fuel is sucked through the carburetor 22 which, in turn, passes the fuel into the piston cylinder 20. If this process continues without sufficient air entering the piston cylinder, the engine will become flooded.
As the engine begins to start, a vibratory shock wave is sent throughout the engine. This shock wave excites the biasing member 46 which, in turn, excites the inertia valve member 44. The biasing member 46 deflects to permit the inertia valve member 44 to disengage from its seating engagement with the seating member 50. This disengagement enables a controlled amount of combustion air to enter into the carburetor 22 which, in turn, enables a proper air/fuel mixture to enter into the piston cylinder 20 enabling the engine 12 to continue to run without a "false start".
As the engine continues to run, the inertia valve member 44 continues to vibrate away from the seating member 50 enabling combustion air to continue to enter into the piston cylinder 20. The engine continues to run under this choked condition for several seconds. The user thus has enough time to rotate the seating member 50 so that the apertures 64 of the wall 62 of the seating member 50 are in alignment with the apertures 40 and 42 of the projecting member 34. The choke is now in its open position and combustion air bypasses the inertia valve member 44 and is sucked directly into the carburetor 22 which, in turn, permits the proper air/fuel ratio into the piston cylinder 20.
Thus, the choke of the present invention permits the engine to continuously run under choked conditions for several seconds. This time gives the operator sufficient time to align the apertures of the seating member with the apertures of the projecting member so that continuous running of the engine is accomplished.
While it will be apparent that the preferred embodiment is well calculated to fill the above-stated objects, it will also be appreciated that the present invention is susceptible to modification, variation, alteration and change without varying from the scope and spirit of the present invention. | A choke assembly or starting aid for small internal combustion engines is disclosed. An inertia valve is resiliently biased in the bore of the engine. The inertia valve is responsive to vibration of the internal combustion engine for providing a controlled amount of combustion air into the carburetor of the internal combustion engine. | 5 |
CROSS-REFERENCE TO A RELATED APPLICATION
[0001] Pursuant to 35 U.S.C. §119(a), this application claims the benefit of earlier filing date and right of priority to Korean Application 10-2009-0018146, filed on Mar. 3, 2009, the content 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 graphene composite nanofiber, and particularly, to a graphene composite nanofiber including monolayer graphenes and multilayer graphenes having a thickness of 10 nm or less, and having a nanoscale fibrous shape, and a preparation method thereof.
[0004] 2. Background of the Invention
[0005] Graphene is a monolayer of graphite, and is a sheet of carbon atoms bound together with double electron bonds (called as an sp 2 bond) in a thin film only one atom thick. Atoms in graphene are arranged in a honeycomb-style lattice pattern. This graphene is a very thin single flat sheet having a thickness of about 0.3 nm, and is a two-dimensional (2D) material for carbon. This graphene was firstly discovered by Andre Geim and Kostya Novoselov at Manchester University in England in 2004 (Novoselov, K. S. et al., Science, 2004, 306, 666-669). According to the American Physical Society (APS) and the English Nature Nanotechnology, this graphene is being spotlighted as one of the most remarkable new materials which can change the future information technology.
[0006] Differently from other carbon allotropes (e.g., carbon nanotube, graphite), the graphene is a semiconductor material having an energy gap of ‘0’. The graphene has characteristics such as high electron mobility, a quantum-hole characteristic (electrons inside graphenes behave like relativistic particles having no rest mass, with a speed of about 1,000,000 m/s), a low specific resistance, high to mechanical strength, and a wire surface area. Furthermore, the graphene is much more advantageous than carbon nanotubes due to low costs in an economic aspect.
[0007] However, in the aspect of application fields, the graphenes have a difficulty in being processed and treated like other carbon allotropes. Each layer of graphite (i.e., each graphene layer) is stacked to each other due to Van der Waal's force (5.9 kJ/mol carbon), thereby not implementing a physical property of a graphene monolayer. Since the first discovery of the graphenes, research has been mainly executed with respect to a method for preparing graphenes from graphite and dispersing the graphenes (Novoselov, K. S. et al., Science 2004, 306, 666-669), an analysis of various characteristics of graphenes (Kern, K. et al., Nano Lett. 2007, 7, 3499-3503), a method for preparing a graphene composite material (Stankovich, S. et al., Nature 2006, 442, 282-286), application fields to a transistor or a sensor (Vandersypen, K. et al., Nature Mater. 2008, 7, 151-157). Among the above research, the research about a graphene composite material has been actively executed based on suspension and dispersion of a graphene monolayer into a polymer matrix. And, research about a method for forming a graphene composite having a nanoscale one-dimensional structure has never been executed.
SUMMARY OF THE INVENTION
[0008] Therefore, a first object of the present invention is to provide a graphene composite in the form of a nanoscale one-dimensional structure, the graphene composite in which graphene monolayers (hereinafter, will be also referred to as “monolayer graphenes”) and/or graphene multilayers (hereinafter, will be also referred to as “multilayer graphenes”) having a thickness of 10 nm or less are well-dispersed.
[0009] A second object of the present invention is to provide a method for orienting (aligning) the monolayer graphenes and/or multilayer graphenes in a specific direction in the form of the one-dimensional structure.
[0010] A third object of the present invention is to provide a carbon nanofiber including the monolayer graphenes and/or multilayer graphenes.
[0011] To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is provided a graphene composite nanofiber produced by dispersing graphenes to at least one of a surface and inside of a polymer nanofiber or a carbon nanofiber having a diameter of 1˜1000 nm, wherein the graphenes comprise at least one type of monolayer graphenes, and multilayer graphenes having a thickness of 10 nm or less.
[0012] To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is also provided a method for preparing a graphene composite nanofiber, the method comprising: preparing a spinning solution in which polymers are dissolved and graphenes are dispersed, wherein the graphenes comprise at least one type of monolayer graphenes, and multilayer graphenes having a thickness of 10 nm or less; and spinning the spinning solution in the form of fibers in an electric field thereby preparing a graphene composite nanofiber where the polymers and the graphenes are combined with each other.
[0013] The present invention may have the following effects.
[0014] Firstly, may be produced a graphene composite nanofiber produced by dispersing monolayer graphenes, and/or multilayer graphenes having a thickness of 10 nm or less, to at least one of a surface and inside of a nanofiber, with an orientation (alignment) parallel to an axis of the nanofiber.
[0015] Secondly, owing to a unique property and a one-dimensional nano structure of graphenes, the graphene composite nanofiber may have a very excellent mechanical and/or electric characteristic. Accordingly, the graphene composite nanofiber may be applied to various industrial fields, e.g., a light emitting display, a micro resonator, a transistor, a sensor, a transparent electrode, a fuel cell, a solar cell, a secondary cell, and a composite material.
[0016] The foregoing 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
[0017] The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention.
[0018] In the drawings:
[0019] FIG. 1 is a schematic view showing a method for preparing a graphene composite nanofiber according to the present invention.
[0020] FIG. 2 is an image showing a graphene dispersion solution after seven days, the solution in which monolayer graphenes and multilayer graphenes having a thickness of 10 nm or less are dispersed, each graphenes prepared by a chemical method;
[0021] FIG. 3 is a transmission electron microscopy (TEM) image of the graphene dispersion solution of FIG. 2 ;
[0022] FIG. 4 shows a scanning electron microscopy (SEM) image of a PVA fiber including no graphenes;
[0023] FIG. 5 shows a scanning electron microscopy (SEM) image of a PVA/graphene composite nanofiber prepared according to a first embodiment of the present invention; and
[0024] FIG. 6 shows a TEM image of a PVA/graphene composite nanofiber prepared according to a first embodiment of the present invention in a lengthwise direction, and a TEM image indicating a sectional surface of the PVA/graphene composite nanofiber (inset of the lower image indicates a diffraction image of the circle).
DETAILED DESCRIPTION OF THE INVENTION
[0025] Description will now be given in detail of the present invention, with reference to the accompanying drawings.
[0026] In the present invention, “monolayer graphenes” signifies a planar monolayer of graphite (0001), and “multilayer graphenes” signifies a stacked structure of the “monolayer graphenes” having several to several tens of layers.
[0027] The multilayer graphenes have a thickness thicker than that of the monolayer graphenes, and less than 10 nm (about less than 20 layers), preferably, to less than 5 nm (about less than 10 layers).
[0028] The graphene composite nanofiber according to the present invention is characterized in that graphenes are dispersed to a surface and/or inside of a nanofiber. Here, the nanofiber has a diameter of 1˜1000 nm, preferably 10˜500 nm, more preferably 100˜200 nm. The nanofiber may be a polymer nanofiber formed of polymers, or a carbon nanofiber prepared by carbonizing the polymer nanofiber. The graphenes include at least one type of monolayer graphenes, and multilayer graphenes having a thickness of 10 nm or less. When the multilayer graphenes have a thickness more than 10 nm, they are present in the form of a graphite plate implemented as the graphenes are bonded to each other. As a result, mechanical and electric characteristics of the graphenes can not be prepared. For instance, when the multilayer graphenes have a thickness more than 10 nm, charge mobility is significantly degraded when being applied to a semiconductor device. Furthermore, mechanical strength due to complexity with other materials is significantly degraded.
[0029] In order to produce desired mechanical and electric characteristics of the graphenes, the graphenes are preferably oriented (aligned) parallel to an axis of the nanofiber. The reason is as follows. When the graphenes are oriented parallel to an axis of the nanofiber, an electric characteristic of the graphenes is implemented along the orientation direction, and mechanical strength in the orientation direction is significantly increased.
[0030] When the multilayer graphenes have a thickness more than 10 nm, it is difficult to implement the orientation characteristic.
[0031] The graphenes dispersed in the nanofiber may be graphene oxides in an oxidized state, or may be graphenes produced by reducing (deoxidizing) the graphene oxides. As explained later, a graphene oxide solution in an oxidized state is prepared so as to implement dispersability of graphenes inside a solvent. By mixing the graphene oxides with polymers and spinning the mixture, may be produced a graphene composite nanofiber that graphene oxides are dispersed to a nanofiber. This graphene composite nanofiber has an excellent mechanical characteristic, but has a degraded electric characteristic since it is present in the form of graphene oxides. Therefore, when an excellent electric characteristic is required, applied is an additional process for reducing the graphene oxides after the spinning process.
[0032] A method for preparing a graphene composite nanofiber according to the present invention largely comprises preparing a spinning solution (1), and preparing a graphene composite nanofiber (2).
[0033] The method may further comprise carbonizing the graphene composite nanofiber produced through the step (2), so as to produce a carbon fiber including graphenes. In this case, the method may further comprise performing an insolubilization process in air before carbonizing the graphene composite nanofiber. Hereinafter, each step will be explained in more detail. FIG. 1 is a schematic view showing a method for preparing a graphene composite nanofiber according to the present invention.
Preparation of Spinning Solution
[0034] Firstly, prepared is a spinning solution in which polymers are dissolved and graphenes are dispersed. The graphenes include at least one type of monolayer graphenes, and multilayer graphenes having a thickness of 10 nm or less.
[0035] A spinning solution may be prepared by the following three methods.
[0036] Firstly, prepared is a graphene solution that the graphenes are dispersed in a solvent, and then polymers are dissolved in the graphene solution, thereby producing a spinning solution. Secondly, additionally prepared is a polymer solution in which polymers are dissolved, and then the polymer solution is mixed with the graphene solution, thereby producing a spinning solution. Thirdly, graphenes are put in the polymer solution thus to be dispersed, thereby producing a spinning solution. Among these three methods, the first method is preferable for dispersability of graphenes and accuracy of concentration control. More concretely, in case of dispersing about 1 wt % of graphenes by concentration based on polymers and dispersing at least 10 wt % of polymers, if an additionally prepared polymer solution is mixed with the graphene solution (i.e., graphene oxide solution) by the second method, it is difficult to increase a concentration of the polymers due to limitations of solubility of the graphene oxide solution. For instance, in case of putting about 1 wt % of graphenes to 10 wt % of polymers, if 9 mL of water is put, about 1 g of the polymers and about 0.01 g of the graphenes have to be used. In this case, solubility of the graphene oxide solution nearly reaches a limitation value, ca. 1 mg/ml. Therefore, it is preferable to firstly disperse graphenes in water, and then to disperse polymers therein by the first method.
[0037] The graphene solution may be prepared by the following three methods. Generally, graphenes are easily bonded to each other, whereas graphene oxides are well-dispersed in a solvent. Therefore, prepared is a graphene oxide solution in an oxide state. In the present invention, the term of “graphene solution” will be also referred to as “graphene oxide solution”.
[0038] Firstly, the graphene oxide solution may be produced by performing acid treatment and sonication with respect to graphite (chemical method). More concretely, graphite is added to a mixed solution of sulfuric acid and nitric acid. Next, the mixture is sonicated (using a voltage more than 200 W) for one or more hours, thereby producing a dispersed solution. In case of aging the dispersed solution at room temperature for three or more days, it turns purplish brown. Next, the dispersed solution is washed by water, and then multilayer graphenes (having a thickness of about several tens of nm) is filtered, the multilayer graphenes of which interlayer gap has been widened by centrifugation and filtering methods. Next, the multilayer graphenes are oxidized by a strong oxidant, thereby producing multilayer graphenes oxides. These multilayer graphenes oxides undergo heat treatment and sonication, thereby producing monolayer graphenes oxides, or multilayer graphenes oxides having a thickness of 10 nm or less. Next, the oxides undergo centrifugation and filtering processes, thereby producing a graphene oxide solution having a yellowish brown color.
[0039] Secondly, graphite is consecutively exfoliated with using a cellophane tape, thereby producing monolayer graphenes, and/or multilayer graphenes having a thickness of 10 nm or less (physical method). Next, these monolayer graphenes, and/or multilayer graphenes are put in a solvent, and undergo acid treatment and sonication, thereby producing a graphene oxide solution.
[0040] Thirdly, Si on the surface of SiC is sublimated by an epitaxial growth method through pyrolysis (thermal decomposition) of the SiC under a vacuum atmosphere, thereby producing graphenes produced by carbon atoms remaining on the surface of the SiC. Next, these monolayer graphenes, and/or multilayer graphenes having a thickness of 10 nm or less are put in a solvent, and undergo acid treatment and sonication, thereby producing a graphene oxide solution.
[0041] The present invention is not limited to the above three methods. That is, the graphene oxide solution may be produced by various methods rather than the above three methods.
[0042] As the polymers of the present invention, may be used all types of polymers that can be dissolved by a solvent, and that can be spun (e.g., electrospun) in an electric field. For instance, the polymers may include poly(vinylidene fluoride), poly(vinylidene fluoride-co-hexafluoropropylene), polyacrylonitrile, poly(acrylonitrile-co-methacrylate), polymethylmethacrylate, polyvinylchloride, poly(vinylidenechloride-co-acrylate), polyethylene, polypropylene, etc. (1), nylon-based polymers such as nylon 12 and nylon-4,6 (2), aramid, polybenzimidazole, polyvinylalcohol, cellulose, cellulose acetate, cellulose acetate butyrate, polyvinyl pyrrolidone-vinyl acetates, poly(bis-(2-(2-methoxy-ethoxyethoxy)) phosphazene, poly(ethylene imide), poly(ethylene succinate), poly(ethylene sulphide), poly(oxymethylene-oligo-oxyethylene), poly(propylene oxide), poly(vinyl acetate), polyaniline, poly(ethylene terephthalate), poly(hydroxy butyrate), poly(ethylene oxide), SBS copolymer, poly(lactic acid), etc. (3), biopolymer such as polypeptide and protein (4), phenolic resin (5), and pitch-based polymers such as coal-tar pitch and petroleum pitch.
[0043] Alternatively, not only the copolymer and blend of the polymers, but also a mixture of emulsion or organic/inorganic powder may be used as the polymers. As the solvent, may be properly used a solvent capable of dissolving a corresponding polymers, and capable of dispersing graphenes according to the polymers.
Preparation of Graphene Composite Nanofiber
[0044] Next, the prepared spinning solution is spun in the form of fibers in an electric field, thereby preparing a graphene composite nanofiber in which the polymers and the graphenes are combined with each other.
[0045] The spinning method may be an electrospinning method. For instance, the spinning solution in which graphenes are well-dispersed is put in a dosing pump, and an electric field of a high voltage is applied between a spinning nozzle and a collector. As a result, the spinning solution is discharged from the spinning nozzle, and the graphene composite nanofiber is collected on the collector in the form of a web or a non-woven fabric in which graphene composite nanofibers are entangled with each other.
[0046] The spinning method may include electro-blown spinning, melt-blown spinning, and flash spinning rather than the electrospinning.
[0047] The prepared graphene composite nanofiber is produced by dispersing the graphenes to a nanofiber composed of polymers aligned in an oxide state with a high orientation degree.
[0048] In order to orient the polymer composite nanofiber finally produced in the present invention, the spinning may be performed into an electric field formed by two electrodes, or formed inside a drum type of electrode being rapidly rotated. In this case, the formed fiber is oriented to a specific direction by a magnetic field.
[0049] The graphenes include at least one type of monolayer graphenes, and multilayer graphenes having a thickness of 10 nm or less. The graphene composite nanofiber has a diameter of 1˜1000 nm, preferably 10˜500 nm, more preferably 100˜200 nm.
[0050] In application fields requiring an excellent electric characteristic, further comprised is an additional process for reducing graphene oxides from the graphene composite nanofiber. More concretely, graphene oxides may be reduced from the graphene composite nanofiber by selecting one of the following three methods, or by combing the three methods with each other. The first method is to reduce graphene oxides by exposing the graphene composite nanofiber to a gaseous or liquid chemical drug including a hydrogen oxide (e.g., hydrogen iodide, hydrogen sulfide, aluminum hydride, etc.), a low oxide (an oxide having an oxidation degree than that of a general oxide lower by one degree) (e.g., carbon monoxide, sulfur dioxide, etc.), salt of low oxyacid (e.g., sulfite, sodium sulfide, etc.), metal having large electropositivity, i.e., metal that can easily transit to a positive ion (e.g., alkali metal, magnesium, zinc, etc.), an organic compound having a low oxidation degree (e.g., aldehyde, sugars, formic acid, oxalic acid, etc.). The second method is to reduce graphene oxides by contacting the graphene composite nanofiber to hydrogen by blowing the hydrogen into the graphene composite nanofiber. And, the third method is to reduce graphene oxides by irradiating strong optical energy (light) onto the graphene composite nanofiber.
[0051] Thirdly, graphene oxides including reduced graphenes may be reduced from the graphene composite nanofiber by reducing the spinning solution by using the aforementioned chemical drug or by blowing hydrogen before the spinning process, and then by spinning the reduced spinning solution. In order to remove impurities which are present in the spinning solution by the reduction process, the reduced spinning solution may be precipitated by a non-solvent. Then, the precipitated spinning solution may undergo a filtering process and a washing process, thereby removing a residual solvent, a reducing agent, impurities, etc. Next, the spinning solution may undergo a drying process thus to produce high purity powder where graphenes and polymers are mixed to each other. Then, the high purity powder is re-dispersed to a solvent by sonication, a stirring process, heat treatment, etc. And, this reduced spinning solution may be spun.
Preparation of Carbon Nanofiber Including Graphenes
[0052] The present invention may further comprise carbonizing the prepared graphene composite nanofiber.
[0053] The carbonization process may be performed under an inactive atmosphere (e.g., nitrogen atmosphere) at 500˜3000° C. Through this carbonization process, polymers of a nanofiber is carbonized to form a carbon nanofiber. Accordingly, can be produced a graphene composite nanofiber produced by dispersing graphenes to at least one of a surface and inside of the carbon nanofiber with a high orientation degree.
[0054] Before the carbonization process, the present invention may further comprise a crosslinking process (insolubilization process) for preventing the graphene composite nanofiber produced by the spinning process from being melted or thermally decomposed due to the carbonization process.
First Embodiment
[0055] 10 g of graphite (Aldrich) was put in a flask containing 7.5 g of NaNO 3 (99%). Next, 621 g of H 2 SO 4 (96%) was slowly added to the mixture, and was cooled. To this mixture, 45 g of KMnO 4 was slowly added for 1 h. The mixture was cooled for 2 h, and then was reacted for four days while being slowly stirred at 20° C. Next, a solution having a high viscosity was diluted in 250 mL of exceptionally high purity distilled water with maintaining a temperature below 50° C., and then was stirred for 2 h. To this resultant, added were 700 mL of exceptionally high purity distilled water and 20 mL of H 2 O 2 (30%), thereby producing a yellow solution with bubbling. Next, this mixed solution was filtered, and metallic impurities were removed by using 1 L of HCL aqueous solution (volume ratio of HCl:H 2 O is 1:10). Next, the mixed solution was washed a plurality of times with using exceptionally high purity distilled water, thereby having a neutral pH value. Next, residual metallic ions in the mixed solution were removed by a dialysis process. This prepared 0.1 mg/mL of solution was sonicated (400 W) at room temperature for about 30 minutes, thereby producing a graphene oxide solution as shown in FIG. 2 , the graphene oxide solution in which graphene oxides are stably dispersed to water even after one week. As an analysis result of the graphene oxide solution with using a transmission electron microscopy (TEM), as shown in FIG. 3 , at least 90% of the graphene oxides were implemented as single layers and exhibited a structure that ending portions thereof are rolled-up. The graphene oxides were put into H 2 O solution so that a weight ratio of the graphene oxides with respect to polyvinylalcohol (PVA) could be 0.01-2 wt %. Next, the graphene oxides were re-dispersed to the H 2 O solution by sonication, a stirring process, etc. Next, a spinning solution was prepared by controlling a weight ratio of the PVA with respect to the H 2 O as 10 wt %.
[0056] This prepared spinning solution was put in a dosing pump, and electro spinning was performed by controlling a voltage of 5˜20 kV to be applied, thereby producing a graphene composite nanofiber non-woven fabric. As shown in the SEM image of FIG. 4 , the conventional PVA nanofiber exhibited a welding structure on a spun substrate. On the contrary, FIG. 5 exhibited a graphenes/PVA composite nanofiber having a stable fiber structure, and including graphenes having a diameter of about 120˜200 nm and having a weight ratio of 0.1 wt %. Referring to FIG. 6 , graphenes were oriented, in a position selection manner, with a thickness less than 5 nm (less than about ten layers) towards the surface of the composite nanofiber. From a highly-magnified image and a diffraction image showing a sectional surface of the graphene/PVA composite nanofiber, crystallinity of graphenes located on the surface of the composite nanofiber could be observed.
Second Embodiment
[0057] Graphite layers were consecutively exfoliated with using a cellophane tape, thereby producing a multilayer graphenes film having a thickness of 5 nm or less. 0.3 g of the graphite produced in a mechanical manner was added to 20 mL of H 2 SO 4 (96%) at 0° C. To this mixture, 15 g of KMnO 4 was slowly added with maintaining a temperature of 20° C. This mixed solution was stirred for 2 h with maintaining a temperature of 35° C. Next, the mixed solution was diluted in 120 mL of exceptionally high purity distilled water with maintaining a temperature below 50° C., and then was stirred for 2 h. To this resultant, added were 700 mL of exceptionally high purity distilled water and 20 mL of H 2 O 2 (30%), thereby producing a yellow solution with bubbling. Next, this mixed solution was filtered, and metallic impurities were removed by using 1 L of HCL aqueous solution (volume ratio of HCl:H 2 O is 1:10). Next, the mixed solution was washed a plurality of times with using exceptionally high purity distilled water, thereby having a neutral pH value. Next, residual metallic ions in the mixed solution were removed by a dialysis process. Graphenes were put into an N,N-dimethylformamide (DMF) solution so that a weight ratio of the graphenes with respect to Polyacrylonitrile (PAN) could be 0.5˜5 wt %. Next, the graphenes were re-dispersed to the DMF solution by sonication, a stirring process, etc. Next, a spinning solution was prepared by controlling a weight ratio of the PAN with respect to the DMF as 5˜20 wt %.
[0058] This prepared spinning solution was put in a dosing pump, and electro spinning was performed by controlling a voltage of 5˜20 kV to be applied, thereby producing a non-woven fabric of a graphenes/PAN composite nanofiber.
Third Embodiment
[0059] The graphenes/PAN composite nanofiber prepared according to the second embodiment underwent an insolubilization process in air at 260° C. (during the insolubilization process, polymers are heated, and have a net-shaped three-dimensional structure thus to be cured. Accordingly, in case of forming a carbon fiber, it is more advantageous for a cured resin to undergo a graphitization process). Then, the graphenes/PAN composite nanofiber was carbonized up to 1400° C. under a nitrogen atmosphere, thereby preparing a graphene composite carbon nanofiber.
Comparative Example
[0060] 10 g of graphite (Aldrich) powder (having a diameter of about 20 μm) was put in an N,N-dimethylformamide (DMF) solution. Next, the graphite powder was dispersed to the DMF solution by sonication, a stirring process, etc. Next, a spinning solution was prepared by controlling a weight ratio of the PAN with respect to the DMF as 0.01˜2 wt %, the same ratio as that in the aforementioned First Embodiment.
[0061] This prepared spinning solution was put in a dosing pump, and electro spinning was performed by controlling a voltage of 5˜20 kV to be applied, thereby producing a graphite/PAN composite nanofiber. Here, partially entangled fibers and graphite lumps were observed.
[0062] The foregoing embodiments and advantages are merely exemplary and are not to be construed as limiting the present disclosure. The present teachings can be readily applied to other types of apparatuses. This description is intended to be illustrative, and not to limit the scope of the claims. Many alternatives, modifications, and variations will be apparent to those skilled in the art. The features, structures, methods, and other characteristics of the exemplary embodiments described herein may be combined in various ways to obtain additional and/or alternative exemplary embodiments.
[0063] As the present features may be embodied in several forms without departing from the characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its scope as defined in the appended claims, and therefore all changes and modifications that fall within the metes and bounds of the claims, or equivalents of such metes and bounds are therefore intended to be embraced by the appended claims. | Disclosed are a graphene composite nanofiber and a preparation method thereof. The graphene composite nanofiber is produced by dispersing graphenes to at least one of a surface and inside of a polymer nanofiber or a carbon nanofiber having a diameter of 1˜1000 nm, and the graphenes include at least one type of monolayer graphenes, and multilayer graphenes having a thickness of 10 nm or less. The graphene composite nanofiber can be applied to various industrial fields, e.g., a light emitting display, a micro resonator, a transistor, a sensor, a transparent electrode, a fuel cell, a solar cell, a secondary cell, and a composite material, owing to a unique structure and property of graphene. | 2 |
BACKGROUND OF THE INVENTION
The present invention pertains generally to magnetic water conditioning devices and more particularly to magnetic water conditioning devices disposed within a water heater.
Over the last several years the efficiency of commercial and residential water heaters has been improved in response to the increasing cost of fuel. One such improved efficiency design is described in U.S. Pat. No. 4,397,296. The water heater described in that patent, like most water heaters, comprises a water containing vessel, a water inlet pipe, a water outlet pipe, a combustion chamber and associated equipment.
A problem common to all water heaters, but of particular concern in high efficiency water heaters, is the formation of scale on the interior surfaces of the water containing vessel. This scale is formed from impurities in the water such as calcium salts and magnesium salts and adheres to the surfaces of the vessel including the surfaces of the combustion chamber through which heat is transferred to the water within the vessel. Scale build up on vessel surfaces, particularly combustion chamber surfaces, significantly impedes the efficient operation of the water heater by interfering with heat transfer to the water. In extreme cases, scale accumulation can cause operating temperatures of combustion chamber surfaces to rise and shorten the useful life of a water heater.
Magnetic devices have been used in the past to combat scale formation. In general, these devices operate by passing the water to be treated through magnetic fields. The scale forming salts are caused to nucleate in the water by the magnetic fields. The nucleated salts do not adhere to water heater surfaces to form harmful scale.
One of the most successful of these magnetic devices is described by Shalhoob et al in U.S. Pat. No. 4,216,092. Shalhoob describes a device to be inserted into a water heater cold water inlet pipe comprised of a non-magnetic cylindrical outer housing and a cylindrical insert contained within the housing. The housing contains the flow of water through the device and has a series of turbulence inducing circumferential ridges spaced along its length. The insert consists of a series of cylindrical magnets having their magnetic poles on their axial ends separated from one another by cylindrical spacers. Adjacent magnets have similar poles facing one another across the intervening spacers. This arrangement provides strong radial magnetic fields concentrated at the ends of the magnets. Water passing through the device flows through the magnetic fields in a direction perpendicular to the strong radial magnetic fields. Magnetic effects on ions and salts contained in the water are most pronounced when the direction of water flow is perpendicular to the magnetic fields. Salts are caused to nucleate in the flowing water rather than on the interior surfaces of the water heater vessel. The magnetically nucleated salts are then flushed from the system.
The device described by Shalhoob is a complex device. The large cylindrical insert requires that the housing have a much larger diameter than the pipe feeding water to the device in order to maintain adequate flow. Therefore, the device must be added on the water heater by cutting out a segment of the cold water inlet pipe and replacing the removed segment with the device. Moreover, the housing itself must be processed into a complex form to provide flow restriction ridges. This adds to the cost of the device. The magnetic fields of the Shalhoob device have large components perpendicular to the direction of water flow only near the magnetic poles. Over most of the length of the device, the principal direction of water flow and the magnetic fields are substantially parallel.
SUMMARY OF THE INVENTION
The present invention contemplates a new and improved apparatus and method which overcomes all of the above referred to problems and others and provides a magnetic water conditioning device which is an integral part of the water heater it is protecting and is easily and economically installed in the water heater.
In accordance with the present invention, there is provided a magnetic scale inhibiting apparatus comprised of a plurality of thin magnets assembled with spacers and disposed within the inlet tube of a heater. The magnets are orientated with their north poles all on one side of the axis of the inlet tube and their south poles all on the opposite side of the axis of the inlet tube thereby providing magnetic fields of semi-circular shape perpendicular to the axis of the inlet tube and thus, the principal direction of water flow, over the entire length of the apparatus.
Further in accordance with the invention, the spacers between adjacent magnets comprise transverse sections interconnecting longitudinal sections and forming receptacles for the ends of adjacent magnets firmly locking them in assembled position.
Yet further in accordance with the invention, the transverse sections of the spacers extend laterally outwardly from the longitudinal sections providing turbulence inducing ridges.
Yet further in accordance with the invention, the spacers are somewhat resilient and are sized to engage the sides of the tube in which the device is inserted, thereby allowing an assembled magnetic scale inhibiting device to be pushed into an inlet tube to a desired position which the device will maintain.
Yet further in accordance with the invention, the magnets have a width only slightly less than the inside diameter of the inlet tube and a thickness small in comparison to their width.
Still further in accordance with the invention, the magnetic scale inhibiting device is contained within the dip tube portion of a water heater inlet contained within the water heater vessel itself.
Still further in accordance with the invention, the magnetic scale inhibiting device is assembled with the water heater by pushing it into the dip tube.
The principal object of the present invention is the provision of a magnetic scale inhibiting device within a water heater.
Another object of the present invention is the provision of a magnetic scale inhibiting device of small cross section which will only minimally impede the flow of a fluid around it.
Still another object of the present invention is the provision of a magnetic scale inhibiting device which does not require a housing having a larger diameter than the tube into which it is inserted.
Yet another object of the present invention is the provision of a magnetic scale inhibiting device providing a magnetic field which is almost uniformly perpendicular to the principal direction of fluid flow around the device.
Still another object of the present invention is the provision of a magnetic scale inhibiting device which can be easily positioned in the dip tube of a water heater by pushing it into the dip tube to the desired position which it will maintain.
Still another object of the present invention is the provision of a magnetic scale inhibiting device which will induce turbulent fluid flow in the areas of maximum usable magnetic field strength and accelerated flow in the areas of minimum magnetic field strength.
The invention may take physical form in certain parts and arrangements of parts, the preferred embodiment of which will be described in detail in the specification and illustrated in the accompanying drawings which form a part hereof.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side elevation of a water heater, partially broken away, showing the major elements of the water heater and the location of the magnetic scale inhibiting device;
FIG. 2 is a greatly enlarged broken away view showing the dip tube portion of water heater inlet tube broken away with the magnets and spacers forming the magnetic scale inhibiting device disposed there within;
FIG. 3 is a cross section of the dip tube and contained magnetic device taken along line 3--3 of FIG. 2; and,
FIG. 4 is a cross section of an alternate spacer and end piece for use in the magnetic scale inhibiting device.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawings, wherein the showings are for the purposes of illustrating a preferred embodiment of the invention only and not for the purposes of limiting same, the figures show a water heater A comprised of a water containing vessel 10, a combustion chamber 12 contained within the water containing vessel, a flue tube 14 extending vertically from the combustion chamber through the water containing vessel and exiting through its top, a cold water inlet 16 and a hot water outlet 18. Combustion chamber 12 contains a burner 20 which provides heat to the combustion chamber surfaces thereby heating the water 22 contained in the vessel 10. The cold water inlet 16 and the hot water outlet 18 are connected to the building plumbing system through unions 24, 26. Additionally, the water heater includes a thermostat and control mechanism (not shown) feeding fuel to the burner 20 and an insulating jacket (not shown) surrounding the water containing vessel 10 in a conventional manner. All of the above referred to elements are conventional and operate in a conventional manner.
All water entering the water heater A to be heated enters through the cold water inlet 16 which is comprised of an exterior portion 28 and a portion interior to the water containing vessel 10 known as the dip tube 30. The exterior portion 28 and the dip tube 30 are comprised of a continuous piece of tubing having a circular cross section and constant diameter which is preferably plastic but may be brass or any other non-ferrous material.
FIG. 2 shows a broken away segment of the dip tube 30 containing a magnetic water conditioning device B comprised of a plurality of identical magnets 40 spaced from one another by a plurality of identical spacers 42.
Each magnet 40 is a bar magnet of uniform rectangular cross section. Each magnet is disposed along a diameter of the dip tube 30 with the long dimension of the magnet being disposed parallel to the axis of the dip tube. The width of the magnets is slightly less than the inside diameter of the dip tube 30 such that the magnets may be moved along the axis of the dip tube. The thickness of the magnets is substantially less than the width of the magnets and therefore substantially less than the interior diameter of the dip tube 30 such that fluid may flow past the magnets 40 on either side of their width.
Each of the magnets 40 has a single north pole N and a single south pole S. The north poles N of all the magnets 40 are disposed along one side of the axis of the dip tube 30 and the south poles S are disposed along the opposite side of the dip tube axis. Magnetic lines of force 44 representing the magnetic fields produced by the magnets 40 emanate from the north poles N and proceed in a circumferential direction to the south poles S. Because all of the magnets have the same orientation with all of the north poles N on the first side of the axis of the dip tube 30 and all of the south poles S on the second side of the axis of the dip tube, lines of magnetic force do not interconnect adjacent magnets. The magnetic lines of force all proceed from the north pole N of one magnet to the south pole S of the same magnet. Therefore, the magnetic fields produced by the magnets 40 are generally perpendicular to the axis of the dip tube 30 and, hence, the principal direction of fluid flow through dip tube 30. Moreover, the magnetic poles extend along the entire length of each magnet 40. Uniform magnetic fields 44 perpendicular to the axis of the dip tube 30 over the length of each magnet are provided.
The magnets 40 are held in place and separated from one another by several H-shaped spacers 42. The spacers 42 are seen in perspective in FIG. 2 and in cross section in FIG. 3. Each spacer has a width substantially equal to the inside diameter of the dip tube 30. Because of the curvature of the cross section of the dip tube 30, the spacers 42 have a slight interference fit when installed in the dip tube 34. Each spacer is comprised of a transverse member 46 and two longitudinal members 48, 50. The transverse member 46 is thin and separates adjacent magnets 40 by a small distance only. The longitudinal members 48, 50 have a substantially constant thickness, are parallel to one another, and engage the opposite sides of two adjacent magnets 40 over the entire width of the magnets. The two longitudinal members are interconnected at their longitudinal centers by the tranverse member 46. Thus, the interior surfaces 52, 54 of the longitudinal members 48, 50 and the surfaces of the transverse member 46 form receptacles tightly receiving the ends of two adjacent magnets 40. The ends of the adjacent magnets 40 are thereby protected from damage and held in alignment closely spaced from one another. The magnetic fields produced by the magnets 40 are therefore substantially continuous over the entire length of the magnetic water conditioning device B and perpendicular to the axis of the dip tube 30.
The spacer transverse member 46 extends slightly beyond the outside surfaces 56, 58 of the longitudinal members 48, 50. These extensions form two turbulence inducing ridges 60, 62 extending across the entire width of the spacer 42. Of course, the ridges 60, 62 could be replaced by a series of round bumps or other shapes and still obtain the turbulence desired.
The magnetic water conditioning device B is installed into the water heater by first inserting a spacer 42 into the cold water inlet 16, placing a magnet 40 into the spacer 42 and pushing it into the inlet 16. Additional magnets 40 and spacers 42 are alternately inserted until the desired number of magnets are in place. Once the final spacer 42 is assembled on top of the last magnet, a push rod (not shown) is inserted into the cold water inlet 16 and the assembled magnetic water conditioning device B is pushed downwardly into the dip tube 30 to its desired position. Because the spacers are resilient and sized to have a slight interference with the inside of the dip tube 30, the assembly can be easily pushed into the dip tube but, once at its desired position, will hold its place under normal flow conditions.
Once the magnetic water conditioning device B is installed and the water heater is filled, water will flow through cold water inlet 16 and dip tube 30 past the magnetic water conditioning device B. Because the magnets 40 are thin and the spacers 42 are not substantially thicker than the magnets, full flow through the inlet tube is not appreciably impeded.
Water flowing past the magnetic water conditioning device B is traveling principally perpendicularly to the lines of magnetic force 44. Maximum force upon calcium salts and the like is therefore induced. This causes auto-nucleation of these salts. Turbulence is induced in the flow of water by the presence of the spacers 42, which are slightly wider than the magnets, and the turbulence inducing ridges 60, 62. This turbulence mixes the water allowing auto-nucleated salt particles to agglomerate and be carried away.
FIG. 4 shows an alternate spacer design. The alternate spacer 142 is H-shaped in cross section and comprised of a transverse member 146 and two longitudinal members 148, 150. The alternate spacer 142 engages adjacent magnets 40 in a manner identical to the primary spacer 42. The outside surfaces 156, 158 of the longitudinal members 148, 150 of the alternate spacer are curved such that the longitudinal members each have a very thin leading edge, a wide central portion, and a very thin trailing edge. No turbulence inducing bumps are provided. Streamlined surfaces at the junction of adjacent magnets are provided when the alternate spacer 142 is used in place of spacer 42. Also, the alternate spacer 142 occupies less of the cross sectional area of the dip tube 30 than the primary spacer 42. An end insert 170 fits into the recess between the spacer longitudinal members 148, 150 of the top spacer in the magnetic device B. An identical end insert fits into the unoccupied recess of the bottom spacer in the magnetic device B. The end inserts have a bullet shaped cross section and create a streamlined leading edge and trailing edge for the magnetic device B further reducing turbulence. The entire magnetic water conditioning device B presents less resistance to flow when alternate spacers 142 and end inserts 170 are used. More flow through the dip tube 30 can therefore be accommodated. While more flow is accommodated, somewhat less turbulence and mixing of auto-nucleated particles is induced and, therefore, less agglomeration occurs.
Two particular embodiments of the magnetic water conditioning device B have been described. Both of these devices can be inserted into any tubular, non-magnetic water containing vessel of appropriate diameter and perform the anti-scale formation function described. While the device has been described with specific reference to a water heater dip tube, the device can also be used by insertion into any feed water tube leading to any water processing or consuming device. This is accomplished by sizing the spacers and magnets to fit the diameter of the tube into which they are to be inserted and pushing the assembly into the tube to its desired position. No special housing is required.
Obviously, modifications and alterations will occur to others upon the reading and understanding of this specification. It is my intention to include all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof. Having thus described the invention, the following is claimed. | A magnetic scale inhibiting device is easily installed in a water heater inlet dip tube without the need of an external housing. The device comprises a number of thin magnets held in aligned relationship within the dip tube by resilient spacers which engage the magnet and the dip tube. | 5 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of copending U.S. application Ser. No. 786,594 filed Apr. 11, 1977, now abandoned, claiming priority of French patent application 76 27771, filed Sept. 6, 1976 and filing date of the U.S. application and the priority under the Convention of the French application are claimed herefor for all subject matters common to them.
BACKGROUND OF THE INVENTION
1. Field of the Invention
An apparatus for treating edible materials the intended operation of which includes mincing, beating, mixing, cutting, pulverising, whisking, emulsifying and the like. (Class 241/282X) 2. Description of the Prior Art
U.S. Pat. Nos. 3,024,010 issued Mar. 6, 1962 to K. H. Sperling, 3,700,176 issued Oct. 24, 1972 to N. Haber, and French Pat. No. 1,053,044 published Jan. 29, 1954, to C. F. Jaeger, are made of record.
Food mincing and mixing apparatus are well known in many different forms, most of which employ knives or whisks which are rotated in a container or drum for the material to be treated. In one particular form of the apparatus, the knives are mounted for rotation about a horizontal axis within a semi-toric container; for achieving homogeneity of the resulting product, the container is given a rapid rotational movement about a vertical axis passing through the center of the container itself. The resulting complexity of the apparatus limits it to industrial users, such as butchers, bakers and confectioners.
A mixing apparatus which is simpler and therefore suitable for domestic use has a flat-bottomed container, in which one or more horizontal knives rotate adjacent the bottom of the container, with the knife ends passing close to the lateral wall of the container. In such an apparatus, there is a tendency for the treated material to move up in contact with the container wall, to which the material tends to stick and therefore to be incompletely worked by the knives.
SUMMARY OF THE INVENTION
In accordance with the present invention, an apparatus is provided for mincing and/or beating and/or mixing, having a near spherical container for materials to be treated and an inwardly directed protuberance in the form of a truncated cone. A knife or knives are mounted for rotation within the container, on a drive shaft passing through the protuberance. With such an apparatus, material rising up the wall of the container is automatically detached to fall back into the zone of the knife or knives. As the material moves up the wall the surface volume of the wall increases towards the horizontal diametrical plane of the container and facilitates a return movement of the material. Beyond the aforesaid diametrical plane, the forces of gravity on the material overcome the adhesive forces and thus cause the material to fall back into the interior of the container.
Preferably the knife, or one of the knives, has a blade portion which is arcuately curved to conform to the lower interior shape of the container and to extend contiguous thereto, from a location at the upper terminus of the shaft, downwardly along the frustoconical shape of the protuberance, then upwardly along the spherical surface of the container, to terminate in a first plane normal to the axis of rotation of the shaft, and lying between second and third planes passing respectively through the upper end of the shaft and the geometrical center of the sphere, all planes being parallel. The portion of the blade thus shaped is adapted to act on material located within an annular space between the lateral conical surface of the protuberance and the adjacent wall of the container. As a consequence, there is no dead space in which material can accumulate without being acted upon by the knife. There may additionally be at least one flat knife mounted to rotate parallel to the upper face of the protuberance and to operate on material disposed above that annular space. The flat knife or knives thus act on material present in considerable quantity, and/or while the material is falling back into the annular space from the wall. The combination of the actions of the two knives acting in different regions ensures that complete treatment of the material is achieved.
Preferably the shaft is inclined to the vertical at a relatively small or acute angle when the container is in operating position. As a result when there is only a small quantity of material to be treated, that material is located in the bottom portion of the annular space and is subjected very thoroughly to the action of the arcuately-curved knife, without any danger of the knife being operative only on the surface layers of the material. The driving shaft may be driven by any suitable means. However, in the preferred form of the invention, it is rotated by direct connection to the rotor shaft of an electric motor. The motor control circuit includes braking means by which the motor is quickly stopped when its circuit is opened. Coasting of the motor is thus obviated. As a further safety feature, switch means for the motor circuit are provided which are closed only by and in response to closure or emplacement of the cover of the container.
In another and preferred embodiment the container is removable, and can be separated from the base, and the container can be held on the base by securing means. This provision enables, firstly, the items of food to be treated to be placed in the container in advance and, secondly, the container to be very easily cleaned after use and independently of the base.
The invention also provides that the container may be equipped, instead of the knives, with either a slicing disc or a grating disc. In this case the invention provides two different covers, one for use with the knives and the other for use with the discs. The covers are each equipped with a tongue which, after the cover has been placed on the container and the cover has been rotated, forces down a button, thereby closing the starting contact of a motor. Further, the motor incorporates a device which causes the motor to be stopped immediately after the starting contact has been disengaged through the cover being rotated in the opposite direction.
As the cover can only be raised by this rotation in the opposite direction, by which the starting contact of the motor is opened, the user of the apparatus cannot be hurt or injured as, in order to reach the items of food being treated, he has to raise the cover and, hence, to open the starting contact for the motor. This represents a novel feature over the prior art apparatuses.
In accordance with a particular feature of the invention the shaft of the driving device is inclined by an angle of between 5° and 20° relative to the vertical. A number of experiments have shown that an angle within this range permits optimal processing of the items of food by the knives, and causes them to fall back to the base of the container in the most efficient way possible.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a view in vertical section of the apparatus.
FIG. 2 is a section on the line a-b-c-d-e-f of FIG. 1.
FIG. 3 is a perspective view of another embodiment of an apparatus according to the invention.
FIGS. 4a and 4b are front and side views of a cover.
FIG. 5 is a front view of another form of cover.
FIG. 6 is a cross-sectional view of the knives.
FIG. 7 is a cross-section through the container, without the cover.
FIG. 8 is a view of the driveshaft, the base being shown partially cross-sectioned.
FIGS. 9a and 9b are perspective views of two ribs belonging to the base.
FIG. 10 illustrates the means for locking the container to the base.
FIG. 11 is a view of the electrical contact mechanism for starting the motor.
FIGS. 12 and 13 are views from below and in cross section, respectively, of a slicing disc.
FIGS. 14 and 15 are views from below and in cross section, respectively, of a grating disc.
FIG. 16 depicts a wiring diagram, as an example, of a conventional electric braking apparatus which may be adapted to the device of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The apparatus illustrated in FIGS. 1 and 2 has a container 1, which is of near-spherical form and which has a removable cover 2, enabling material to be treated to be introduced into the container. The container 1 is mounted on or in a base or frame 12, by means of two interfitting rings or rims 13 and 14, ring 13 being integral with base 12 and ring 14 being integral with container 1. Base 12 forms a casing for an electric motor 5 having a drive shaft 4, and is so constructed that shaft 4 is inclined to the vertical by an angle ω, when the apparatus is located upon a horizontal table T. The inventor conducted a considerable amount of experiments and ascertained that the near-spherical container must be tilted to the optimum angle which is preferably between 5° to 20°. It will be understood that the motor housing encompasses the control circuitry subsequently described in connection with FIG. 16.
Container 1 is formed at its base with an inwardly-extending protuberance 3 which as shown is in the form of a truncated cone and through which extends the shaft 4 of motor 5. Mounted on the upper end of the shaft by means of a retainer ring 8, are two knives 6 and 7. Knife 6 is flat and as shown extends at right angles to the axis of the shaft. The blade of knife 7 comprises two portions or parts. First part 9 which is substantially planar or flat, closely conforms to the conical surface of protuberance 3 when the appliance is in operation. The other part 10 has a form which as shown upon FIG. 1, extends arcuately upwardly from a point at the outer or distal end of part 9 closely contiguous to the circular intersection of the base of protuberance 3 and the spherical surface of the container, to a point indicated at "d," lying in a plane intermediate a plane through the upper end of shaft 4 and another through the geometrical center of the container, all planes being parallel and normal to the axis of rotation of the shaft.
Part 10 as shown lies closely adjacent the wall of the container.
Also referring to FIG. 2 it is noted that the blade of knife 7, in plan, has the form of an "S," symmetrical with the axis of the shaft, the cutting edges being on and along the convex edges. That is, the blade rotates counterclockwise as viewed upon the figure.
An annular space 11-11' is defined between protuberance 3 and the adjacent wall of the container. It is in that space that the material accumulates when the quantity is small, it being noted that material within the space thus defined, is not subject to the action of blade 6 but, because of the particular form thereof, is subject to the action of blade 7.
The apparatus as described and illustrated is capable of being used for domestic and industrial purposes, only the dimensions varying according to the use for which it is intended. There is no dead space in which material can accumulate, without being treated. The material is thoroughly worked by the knives 6, 7, any material rising up the wall of the container being caused to fall back, as explained above, into the path of the knives. Because of the absence of any dead space, the apparatus can be used for the treatment of small quantities of material, the entire volume at the bottom of the container being swept by knife 7.
Although an electric motor 5 is shown for driving the blade 6, 7, it will be understood that other drive means may be employed, such as a hand driven mechanism.
In the preferred embodiment illustrated in FIG. 3 and in the following Figures an apparatus according to the invention comprises a base 15, a removable container 16, above which is a cover 17.
The base 15 encloses an electric motor (not shown) which drives an inclined shaft 18, which has a frustoconical base 19. The shaft 18 has splines 20. The container 16 has a base having a frustoconical protuberant portion 21 surmounted by a hollow column 22.
The frustoconical shape of the protuberant portion 21 matches that of the base 19, and the height of the hollow column 22 matches the height of the shaft 18.
Also, the upper part of the base 15 is in the form of a dished portion 23, which matches the shape of the lower spherical part of the container 16. Thus, when the container 16 has been placed in position, the frustoconical portion 21 and the column 22 surmount, and closely follow the shape of, the base 19 and shaft 18.
The apparatus comprises a device for attaching the removable container 16 to the base 15 so that, during operation, the container 16 and base 15 cannot be separated from each other. The fastening device comprises means for ensuring that the container 16 will be fast in rotation with the base 15, and means for locking the container 16 and base 15 to one another.
The means for making the container and base fast in rotation with one another are constituted by, firstly, two ribs 24 and 25 on the upper part of the base 15, this upper part being shaped as a dished part 23. The ribs 24 and 25 stand out from the wall 26 of the dished part 23, and lie diametrically opposite one another. These ribs 24, 25 are each constituted by a first, gently inclined face, 27 and 28, and by a second, more steeply inclined face 29 and 30. Container 16 also has two ribs 31 and 32, which are diametrically opposed, on its lower wall.
When the container 16 is placed on to the base 15 and the container 16 is turned in the direction in which the ribs 31 and 32 first meet the faces 27 and 28 (that is to say in the direction of arrows f 1 and f 2 of FIGS. 9a and 9b) it is easy, by continuing this rotation, to cause ribs 31 and 32 to pass ribs 24 and 25. The container 16 will then be in position for operation. The container cannot become disengaged through rotation in the opposite direction from that described above, because it would require the exertion of greater force to cause ribs 31 and 32 to pass ribs 24 and 25, as ribs 31 and 32 would then first have to cross the more steeply-inclined faces 29 and 30.
The means for locking the container 16 to the base 15 comprises two lugs 36, which belong to the base 15, are diametrically opposite one another relative to the shaft 18, and jut out in two recesses 37 formed in the outer wall of the base 15.
Provided for co-operation with the lug 36 are two slots 38 formed in two symmetrically disposed faces 39 on the wall of the container 16, close to the bottom of the latter. These faces 39 are constituted by two cheeks 40 and 41, which are offset relative to one another and interconnected by a shoulder 42.
When, prior to use and when the container 16 is positioned on the stand, the container 16 is turned so as to bring the ribs 31 and 32 in contact with ribs 24 and 25, in the manner described above, lug 36 lies behind cheek 41 and directly behind the part of the slot 38 formed in this cheek 41.
By rotating container 16 in the direction of arrow f 3 in FIG. 10 ribs 31 and 32 are caused to pass ribs 24 and 25, and lug 36 is brought into the part of slot 38 formed in the cheek 40.
The front face 43 of lug 36 comes into contact with the end 44 of slot 38, thereby preventing any continuation of rotation of container 16 relative to the base 15. The lug 36 then participates in making the container fast in rotation with the base.
Further, the lug 36 locks the container to the base, as this lug 36 is completely engaged in the part of the slot lying in cheek 40, and prevents any upward movement of the container relative to the base.
FIGS. 4a and 4b illustrate a cover which is similar to cover 17 illustrated in FIG. 3. It comprises an upper part 45 which is in the form of a spherical cap having a long projecting ridge 46 and two shorter ridges 47 and 48. The three ridges enable the cover to be easily manipulated.
The top of the spherical cap comprises a funnel 49 by means of which materials to be treated can be introduced into the container 16, in particular liquids. At the base of the spherical cap a lower cylindrical extension 50 corresponds to an upper projection 51 belonging to the container, the extension 50 lying within the extension 51 when the cover is in position.
The cover also comprises a circular rim 52 having two segments bent over to define a hook-like portion 53 which is intended to engage under two arcuate protuberances 54 of the upper extension 51 of the container 16. Rotating the cover relative to the container causes the protuberances 54 to engage in the hook-shaped segments 53, so that the cover is locked on to the container.
The cover 17 is equipped with a tongue 55 which is extended by a cranked part 56 composed of two flat segments 57 and 58 which together include a right angle. Segment 58 is cut across to define a bevel, and the two sides 59 and 60 of its lower portion together include an obtuse angle.
The base 15 (FIG. 3), which encloses the motor, comprises an upper extension 61 which forms a hood for a contact for starting the motor of the apparatus. The hood 61 is formed with a slot 62 in which the crank parts 56 can enter.
The slot 62 itself defines an elbow bend and is constituted by a first, substantially horizontal slot 63, which merges into a second, substantially vertical slot 64.
During the turning movement by means of which cover 17 is locked to container 16, the segment 57 enters the slot 63, and segment 58 enters slot 64. During the turning movement of the cover 17 (FIG. 11) in the direction of arrow f 4 the side 59 of segment 58 comes into contact with a spring-loaded push knob 65. This knob or button 65 is pressed down in the direction of arrow f 5 until it abuts against the edge 60, thus closing a switch 66 serving to start the apparatus motor 67. Switch 66 is described with more details in conjunction with FIG. 16.
This reveals a notable feature of the apparatus, that is to say the rotation of the cover relative to the container thus causes this cover to be locked to the container and also causes the motor to be started. As soon as the items of food have been treated rotation of the cover in the opposite direction disengages the push button 65, thereby opening contact 66 and stopping the motor; at the end of the rotation of the cover the hook-shaped segments 53 disengage from the protuberant portions 54 and the cover can be raised.
FIG. 5 illustrates another cover 68 which can be fitted on the container 16. Cover 68 comprises the same means as cover 45 for securing it to the container, viz. rims and hook-shaped segments, and also the same means (as cover 45) for actuating the push button (a cranked tongue). In place of a funnel, cover 68 comprises a spout 69 by means of which the products to be treated can be introduced; cover 68 also comprises a plug or stopper 70.
FIGS. 12, 13 and 14, 15 respectively show discs 71 and 72, which can be fitted on the shaft 18 of the apparatus motor. Disc 71 is extended by an internally splined column or stem, which can engage on the splines 20 of shaft 18.
Stem 73 is connected to disc 71 by three ribs 74 each of which carries a stud 75, in which a screw 76 makes the disc fast with the corresponding rib 74.
Disc 71 is formed with a substantially radial slot 77; a toothed blade 78 is spot-welded (79) slightly above, and set back from, slot 77.
Disc 72 is also extended by a stem 80, which is internally splined in the same manner as stem 73.
Stem 80 is secured to disc 72 in the same way as stem 73 is secured to disc 71. Disc 72 is formed with a number of substantially circular, small orifices 81, and a part 82 of the edge of each orifice 81 is upwardly raised so as to form a number of small knives.
FIG. 6 shows two knives 92 and 93 mounted on a ring 94. These knives 92, 93 each has a blade which is identical to the blade of knives 6 and 7 of FIGS. 1 and 2.
Ring 94 is provided with a central tube 95 which is internally splined in such a way that splines exactly fit on the splines of shaft 18. The space defined between the ring 94 and the inner tube 95 corresponds to the column 22, so that the ring can fit over this column 22 when the apparatus is to be used with the knives.
Knife 92 comprises, like knife 7, two parts, viz. a planar portion 92 a and an arcuate portion 92 b .
As is clear from FIG. 7, in which knife 92 is indicated by dashed line, the length of part 92 b is such that its end lies below the plane P.P', which extends perpendicularly of the shaft 18 passing through the centre of the spherical container.
The two latches of the base and the combination of the two first ribs on the external surface of the ball with the two ribs on the base having a special profile of a gentle slope upwardly and a steep slope downwardly facilitate the anticlockwise rotation necessary to lock the ball and ensures that a clockwise rotation of the ball cannot occur such as from an occasional shock.
Referring to FIG. 16, motor 5 is indicated by dot-dash lines. Although the control parts are or may be enclosed within the motor casing, they are, for clarity of illustration and description, shown apart from the motor, enclosed within the dot-dash rectangle 5a. The motor is a single-phase machine equipped with two field coils 115 and 116, a relay or coupler 117 and a starting condenser 118. Coils 115 and 116 are connected to the neutral N of an a.c. supply. When connected through one pair of terminals 119 of an on-off switch 66 (see also FIG. 11), the motor is supplied by way of a terminal B. As will be noted from FIG. 16, switch 66 includes three pairs of terminals, namely, terminals 119 previously identified, 120 and 121. When in the "off" position shown upon the figure, terminals 120 are bridged. When in the "on" position, terminals 120 are opened and terminals 119 and 121 are closed. Passage of "off" to "on" position is due to the pressing down of spring-loaded push knob 65 by segment 58 as explained previously in connection with FIG. 11.
Contacts or terminals 120 connect phase U and the anode of thyristor T 1 , the cathode of which is connected directly to motor terminal A, and to the anode of diode D 1 . The cathode of D 1 is connected through terminals 121, to motor terminal A. Terminals 121 are shunted by a time-constant circuit comprising resistors R 1 and R 2 , and condenser C 1 . One terminal of the condenser is also connected to the trigger of tyristor T 1 . When terminals 120 are bridged, this time circuit is supplied by diode D 1 , with a half-wave current.
When switch 66 is in the "off" position of FIG. 16, terminals 119 are open and the motor is de-energized. Terminals 120 being closed at this time, condenser C 1 is charged. The voltage on the trigger of T 1 is then equal to that on its cathode and T 1 is blocked.
When switch 66 is moved to its "on" position, terminals 120 are opened and 119 and 121 are closed. The motor is energized through terminals 119. As terminals 121 are also bridged at this time, condenser C 1 is discharged, T 1 becomes unblocked but is not supplied since terminals 120 are open at this time. When switch 66 is again moved to the "off" position of FIG. 16, terminals 119 are opened and motor 5 is no longer supplied. T 1 being then unblocked, is supplied through presently-closed terminals 120. Terminals 121 are also open at this time. Thus motor terminal A is supplied with a half-wave current as indicated at 123, thus producing an instantaneous induction braking. But C 1 is then progressively charged through diode D 1 and resistances R 1 and R 2 . When thus charged, C 1 blocks T 1 , motor terminal A is no longer supplied and the motor is immediately brought to rest.
The combination of the circuitry of FIG. 16 with the ball mount to the base and the safety interlock controlled by the rotation of the cover ensures that the electric circuit is open when the cover is not locked. When the motor is shut off by the unlocking of the cover it stops immediately the shaft and leaves it free to rotate about its axis. | The invention relates to an apparatus for mincing and/or beating, comminuting, chopping, pulverizing, emulsifying, mixing, kneading, whisking and the like of materials, particularly edible materials, such as meat, starchy foods, fruit and vegetables which comprises a near-spherical container, at least one knife mounted for rotation within the container, coupled with safety features to prevent injuries to the operators. | 0 |
CROSS REFERENCE TO RELATED APPLICATION
This application is a continuation-in-part of prior copending application 08/241,874, filed May 12, 1994, now abandoned.
FIELD OF THE INVENTION
This invention relates to the art of catalytic conversion of hydrocarbons to useful hydrocarbon products. More specifically, it relates to the reconditioning of spent hydrocarbon conversion catalyst so that the catalyst can be reused in a hydrocarbon conversion reaction.
BACKGROUND OF THE INVENTION
Catalytic processes for the conversion of hydrocarbons are well known and extensively used. Invariably the catalysts used in these processes become deactivated for one or more reasons. Where the accumulation of coke deposits causes the deactivation, reconditioning of the catalyst to remove coke deposits restores the activity of the catalyst. Coke is normally removed from catalyst by contact of the coke-containing catalyst at high temperature with an oxygen-containing gas to combust and remove the coke in a regeneration process. These processes can be carried out in-situ or the catalyst may be removed from a vessel in which the hydrocarbon conversion takes place and transported to a separate regeneration zone for coke removal. Arrangements for continuously or semi-continuously removing catalyst particles from a reaction zone and for coke removal in a regeneration zone are well known.
In continuous or semi-continuous regeneration processes, coke-laden particles are added and withdrawn from a regeneration zone. In order to combust coke in a typical regeneration zone, coke-containing catalyst particles are contacted with an oxygen-containing recycle gas in a combustion section. Coke combustion is regulated by controlling a low oxygen concentration in the recycle gas. Most of the flue gas, which contains the by-products of coke combustion, is continuously recirculated and forms at least a portion of the recycle gas. A small stream of makeup gas is added to the recycle gas to replace oxygen consumed in the combustion of coke and a small amount of flue gas is vented off to allow for the addition of the makeup gas.
After coke burning, the catalyst requires reconditioning to restore the noble metal, usually platinum, to its most highly catalytic state and to replace chloride on the catalyst that may be lost in the reaction zone or through the regeneration process. Reconditioning for a reforming catalyst will include contact with oxygen and a chlorine-containing compound to redisperse and oxidize the platinum metal and to replace the chloride on the catalyst, followed by a drying step to reduce the moisture content of the catalyst. Alternatively, the reconditioning will involve reversing the order of the redispersion and drying steps. Finally, the catalyst is contacted with hydrogen to change the platinum metal from various oxidized states to a reduced metallic condition.
Prior to the reduction step, it is usual practice to cool the catalyst in a cooling zone. Cooling may be accomplished by passing the catalyst through a cooling vessel containing coils through which cooling water flows. Alternatively, cooling without the use of cooling water may be accomplished by countercurrently contacting the catalyst with a cool gas, such as dried cooled air. After having been heated by the catalyst, the air stream leaving the cooling zone may be used in some or all of the previously-described regeneration steps, including drying, redispersion, and coke combustion.
One of the problems with continuous catalyst regeneration processes is a phenomenon called speckling. Speckling refers to the mottled or speckled appearance of oxidized-metal catalyst particles that have undergone multiple regenerations. It has been observed that the presence of catalyst particles of various shades of color is symptomatic of a general degradation of the physical properties of the catalyst particles, the metal in particular. And it has been observed that performance problems in the reaction section are associated with this speckled appearance. It is believed that the metal has become degraded in the sense that the metal on the catalyst is either not uniformly dispersed or not in a uniform oxidation state. But it has been unknown for a long time why the catalyst particles take on this appearance after multiple regenerations.
INFORMATION DISCLOSURE
U.S. Pat. No. 3,652,231 (Greenwood et al.) shows regeneration apparatus in which a constant-width movable bed of catalyst is utilized. The '231 patent also describes a continuous catalyst regeneration process which is used in conjunction with catalytic reforming of hydrocarbons. U.S. Pat. No. 3,647,680 (Greenwood et al.) and U.S. Pat. No. 3,692,496 (Greenwood et al.) also deal with regeneration of reforming catalyst. The teachings of patents ('231, '680, and '496) are hereby incorporated in full into this patent application.
U.S. Pat. No. 4,647,549 (Greenwood) discloses a regeneration method and apparatus in which an air stream is introduced into the bottom of a regeneration vessel and is heated by exchange of heat with catalyst, thereby effecting cooling of the catalyst. Before passing into a drying zone and then into a combustion zone, the air stream is heated further by heating means located in the regeneration vessel.
Thermal channelling is described in the article by E. P. Wonchala and J. R. Wynnyckyj entitled, "The Phenomenon of Thermal Channelling in Countercurrent Gas-Solid Heat Exchangers," published in The Canadian Journal of Chemical Engineering, Volume 65, October 1987, Pages 736-743.
U.S. Pat. No. 2,696,461 issued to Howard discloses a fluidized catalyst regeneration process that employs a fluidized catalyst cooling zone.
U.S. Pat. Nos. 2,908,636 and 2,965,563 issued to Steffgen et al. disclose basic steps for the regeneration of reforming catalyst.
U.S. Pat. No. 3,701,203 issued to Anderson discloses a method for drying heat-sensitive particles in a moving bed tower that comprises a preheat zone, a steep zone, a drying zone, another steep zone, and a cooling zone.
U.S. Pat. No. 3,986,982 issued to Crowson et al. teaches the completion of reforming catalyst regeneration with a final reduction step.
U.S. Pat. No. 4,621,069 issued to Ganguli discloses a catalyst regeneration process in which hot regenerated catalyst is cooled by indirect heat exchange.
U.S. Pat. No. 4,664,778 issued to Reinkemeyer discloses a catalyst regeneration process in which the oxygen source for the catalyst regeneration step is cooled.
U.S. Pat. Nos. 4,687,637 and 4,701,429 issued to Greenwood disclose a continuous regeneration apparatus and process in which the amount of air supplied to a combustion zone is adjusted independently of the air supplied to a drying zone.
SUMMARY OF THE INVENTION
It has now been recognized that speckling of oxidized catalyst particles may be caused by non-uniform cooling of catalyst particles in continuous regeneration processes. We have recognized that variations in thermal exposure in a cooling zone may affect catalyst properties. This invention is a method of obtaining catalyst particles that have been uniformly exposed to thermal conditions and have been uniformly cooled to a desired degree. With our invention, not only is the desired bulk or average temperature of all the catalyst particles exiting the cooling zone achieved, but also uniformity of temperature among individual catalyst particles is also achieved.
In its broadest aspect, this invention is a method of cooling particles that leave a zone by using a stream that is to be heated before it enters the zone from which the particles leave. More specifically, in a catalyst regeneration process, this invention is a method of operating a cooling zone by bypassing a portion of a cooling stream around the cooling zone and passing it through a drying zone. Also, in a catalyst regeneration process, this invention is a method of operating a cooling zone by venting one portion of a cooling stream after it has passed through the cooling zone, and passing another portion of the stream into a drying zone. This invention obtains proper and independent flow rates through the cooling zone and the drying zone, avoids non-uniform flow patterns in the cooling zone, and results in uniform cooling in the cooling zone.
We have recognized that regeneration processes of the prior art that employ a drying zone and a cooling zone are especially likely to have variations in thermal exposure of catalyst particles that can lead to speckling. In processes of the prior art, the flow rate of the cool air stream to the cooling zone is a rate that is determined by the flow requirements elsewhere in the regeneration process, such as the flow rate that is required either for drying or for coke combustion, whichever is greater.
We have recognized that the flow rates of air typically used for drying or for coke combustion are usually not suitable for cooling the reconditioned catalyst particles because those flow rates typically cause thermal channelling in the cooling zone bed. Thermal channelling is a phenomenon that appears in countercurrent cooling of hot, moving packed beds. It arises because the resistance to the flow of gas through the moving packed bed decreases with decreasing temperature. Within a moving packed bed, once a colder region with respect to the remainder of the bed is established somehow, it becomes the favored flow channel by virtue of its lower resistance to flow. Within the moving packed bed, some vertical regions or channels of relatively-high flow and other channels of relatively-low flow are established.
Thermal channelling can cause two undesirable effects: it can reduce heat transfer efficiency and it can affect the properties of the catalyst. The heat transfer efficiency is reduced, regardless of the catalyst surface area that is available for heat transfer. The gas passing up through the relatively-high flow channel can absorb by heat exchange only the thermal mass of the catalyst that is passing downward through that channel. Likewise, the catalyst that is passing down through the relatively-low flow channel can absorb by heat exchange only the thermal mass of the gas that is passing upward through that channel. Therefore, thermal channelling will always cause an observed loss in thermal efficiency. Second, the properties of the catalyst particles can be affected because some catalyst particles may be exposed to high temperature for longer periods of time than other catalyst particles, even though the average amount of time that the catalyst particles are in the cooling zone may be the same. Variations in the periods of time that individual catalyst particles are exposed to high temperatures can affect properties of the catalyst, such as metal dispersion, moisture content or chloride content, and changes in any of these properties can adversely affect the performance of the catalyst in the reaction zone.
This invention is most suitable for particles and gases having respective flow rates that are related such that the thermal flow rates of the particles and the gases are nearly equal. Thermal flow rate is defined as the product of mass flow rate and the average heat capacity through the operating temperature range. Thus, the thermal flow rate of the particle stream is the product of the mass flow rate of the particle stream and the average heat capacity of the particle stream. Likewise, the thermal flow rate of the gas stream is the product of the mass flow rate of the gas stream and the average heat capacity of the gas stream. Where mass flow rate is measured in units of pound/hour and heat capacity is measured in units of BTU/pound/°F., then the units of thermal flow rate are BTU/hour/°F. See the article by E. P. Wonchala and J. R. Wynnckyj entitled, "The Phenomenon of Thermal Channelling in Countercurrent Gas-Solid Heat Exchangers," published in The Canadian Journal of Chemical Engineering, Volume 65, October 1987, at pages 736-743, the teachings of which are incorporated herein by reference. For purposes of this discussion, it is convenient to define a thermal flow ratio, which is the ratio of the thermal flow rate of a first stream divided by the thermal flow rate of a second stream. The thermal flow ratio has dimensionless units, because the units of the thermal flow rates in both the numerator and the denominator of the ratio are the same.
For a given imposed pressure difference across a moving packed bed of solids that is to be cooled by countercurrent gas flow, if the overall, or average, thermal flow ratio of the gas to solid through the bed is equal to 1, the previously-mentioned article by Wonchala and Wynnyckyj explains that it is unlikely that the entire moving packed bed operates at a thermal flow ratio of gas to solid equal to 1. Instead, the gas distributes itself into channels, each occupying a fraction of the total cross-section of the bed. Some of the channels have a relatively-low gas flow and, hence, a relatively-low thermal flow ratio (e.g., below 0.65), while other channels have a relatively-high gas flow and thermal flow ratio (e.g., above 1.3). The rate of cooling and even the extent of cooling thus varies greatly from one channel to another. The pressure drop from channel to channel remains the same despite differences in channel flow rates because the physical flow properties of the gas vary with temperature.
Only particular pairs of gases and solids flowing countercurrently for the purpose of cooling the solids result in a combination of flow rates and heat capacities such that the thermal flow ratio of gas to solid is equal to 1. One common situation where this arises is in processes for the removal of coke by combustion from spent catalyst particles in hydrocarbon conversion processes. The catalyst particles are typically solid particles comprised of a base material containing alumina, silica, or silica-alumina. By silica-alumina it is meant the wide variety of amorphous and crystalline combinations of silicon, aluminum, and oxygen atoms that form solids, including clays and zeolites. The catalyst particles may also comprise coke, which may typically be 1-25 wt-%, or more, of the weight of catalyst particles in use in hydrocarbon conversion processes. The gases that contact these catalyst particles are typically air, molecular oxygen, and molecular nitrogen.
In these catalyst regeneration processes, the ratio of flow rates of gas to solids that is required to provide makeup gas to combust coke from spent catalyst particles, to dry the catalyst particles after coke combustion, and even to redisperse and oxidize the metal on the catalyst typically includes a range in which the thermal flow ratio of gas to solid is 1.0. Despite variations in the amount and composcatalyst, this is on the catalyst, and on the properties of the catalyst, this is true for a wide range of commercially-important catalysts that can undergo continuous regeneration.
This invention is not limited to processes that employ catalysts comprising silica, alumina, and silica-alumina. It is believed that this invention is also applicable to processes that employ catalysts comprising titanium oxide, phosphoric acid, zirconium oxide, tin oxide, etc. Moreover, this invention is not limited to processes that employ cooling gases that comprise oxygen and nitrogen. This invention is also applicable to processes that employ hydrogen-containing gases or hydrocarbon-containing gases for cooling catalyst particles, such as in cooling coke-containing catalyst particles that are withdrawn from hydrocarbon-processing reactors. Preferably, the cooling fluid absorbs only sensible heat in the cooling zone. For example, if the cooling fluid comprises a liquid, then liquid does not vaporize in the cooling zone.
The present invention provides a method of reactivating a catalyst that has been deactivated by the accumulation of coke on its surface, that requires regeneration to remove coke, and that needs cooling of the catalyst to provide adequate catalytic performance. The present invention is particularly suited for catalysts that use platinum metals and maintain a chloride concentration on the catalyst particles. For such catalyst particles, the arrangement and operation of this method and apparatus will improve the cooling of the catalyst particles.
In a broad embodiment, this invention is a method for cooling particles. Particles are withdrawn from a first zone and passed at least periodically to a second zone. In the second zone a packed bed of the particles is formed. The bed is moved at least periodically to establish a particle thermal flow rate. A first portion of a first gas stream is passed through the bed, thereby cooling the particles and producing a heated first portion. The first portion of the first gas stream contacts the particles in the bed at a gas flow rate that establishes a gas thermal flow rate such that the ratio of the gas thermal flow rate to the particle thermal flow rate in the bed is less than about 0.9 or more than about 1.15. The heated first portion of the first gas stream is withdrawn from the second zone and is combined with a second portion of the first gas stream to form a second gas stream. The second gas stream is heated to produce a heated second gas stream. The heated second gas stream is passed to the first zone and contacts the particles in the first zone. Cooled particles are withdrawn at least periodically from the second zone.
In another embodiment, this invention is a method for cooling particles. Particles are withdrawn from a first zone. The particles are passed at least periodically to a second zone. In the second zone, a packed bed of the particles is formed. The bed is moved at least periodically to establish a particle thermal flow rate. A first gas stream is passed through the bed, thereby cooling the particles and producing a heated first gas stream. The first gas stream contacts the bed at a gas flow rate that establishes a gas thermal flow rate such that the ratio of the gas thermal flow rate to the particle thermal flow rate in the bed is less than about 0.9 or more than about 1.15. The heated first gas stream is withdrawn from the second zone. The heated first gas stream is heated to produce a twice-heated first gas stream, which is passed to the first zone where the twice-heated first gas stream contacts the particles in the first zone. Cooled particles are withdrawn at least periodically from the second zone.
In a more detailed embodiment, this invention is a method for effecting regeneration of catalyst particles used in hydrocarbon conversion reactions. Catalyst particles are passed through a burn zone by means of gravity. The burn zone is maintained at a coke-oxidizing temperature, wherein catalyst particles are contacted with a recycle gas comprising oxygen. The catalyst particles are passed from the burn zone through a catalyst drying zone by means of gravity. In the catalyst drying zone, water is removed from the catalyst particles. The catalyst particles are passed from the catalyst drying zone to a catalyst cooling zone by means of gravity. In the catalyst cooling zone, a packed cooling bed of the particles is formed, and the temperature of the catalyst particles is reduced. The catalyst particles are moved at least periodically through the burn zone, the catalyst drying zone, and the catalyst cooling zone by withdrawing catalyst particles from the catalyst cooling zone and adding catalyst particles to the burn zone, thereby establishing a catalyst thermal flow rate in the catalyst cooling zone. Air drawn from the atmosphere is compressed to an elevated pressure to produce a compressed air stream. The compressed air stream is cooled and passed through an air drying zone. In the air drying zone, water is removed from the compressed air stream, thereby producing a dried air stream. A first portion of the dried air stream is passed through the cooling bed, thereby cooling the catalyst particles and producing a heated air stream. The catalyst particles in the cooling bed are contacted with the first portion of the dried air stream at an air flow rate that establishes an air thermal flow rate such that the ratio of the air thermal flow rate to the catalyst thermal flow rate in the cooling bed is less than 0.9 or more than 1.15. The heated air stream from the catalyst cooling zone is combined with a second portion of the dried air stream to form a combined stream. The combined stream in heated in an air heating zone. At least a portion of the combined stream from the air heating zone is passed through the catalyst drying zone, thereby removing water from the catalyst particles. At least a portion of the gas from the catalyst drying zone is mixed with gas exiting from the catalyst particles in the burn zone to form a flue gas stream. The flue gas stream is withdrawn from the burn zone. A first portion of the flue gas stream is discharged from the process. A second portion of the flue gas stream is passed to the burn zone, thereby providing at least a portion of the recycle gas.
Other objects and embodiments of this invention are discussed in the following detailed description.
BRIEF DESCRIPTION OF THE DRAWING
The drawing is a schematic illustration of a regeneration zone arranged in accordance with this invention and some of the equipment associated therewith.
DETAILED DESCRIPTION OF THE INVENTION
In its broadest aspect, this invention may be used to cool any particles leaving a zone by using a stream that is to be heated before it enters the zone from which the particles are withdrawn. The particles leaving the zone are directly and countercurrently contacted with the gas stream in order to cool the particles and to return to the zone the heat that is recovered from the particles. Particles that are suitable for use in this invention will normally comprise geometric shapes of regular size. In most cases, the particles will have a maximum dimension of less than 1/2 inch. Gases that are suitable for use in this invention will be cooled gases which can exchange heat directly with the withdrawn particles without adversely affecting the particles. When heated, suitable gases will also not be detrimental to the operation or performance of the zone from which the particles are withdrawn. Preferably, the stream of heated gases that enters the zone is a stream that is required for the operation and performance of the zone.
The present invention is applicable to a wide variety of hydrocarbon conversion processes including hydrogenation and dehydrogenation processes, but the most widely practiced hydrocarbon conversion process to which the present invention is applicable is catalytic reforming. Therefore the discussion of the invention contained herein will be in reference to its application to a catalytic reforming reaction system. It is not intended that such discussion limit the scope of the invention as set forth in the claims.
Catalytic reforming is a well-established hydrocarbon conversion process employed in the petroleum refining industry for improving the octane quality of hydrocarbon feedstocks, the primary product of reforming being motor gasoline. The art of catalytic reforming is well known and does not require detailed description herein.
Briefly, in catalytic reforming, a feedstock is admixed with a recycle stream comprising hydrogen and contacted with catalyst in a reaction zone. The usual feedstock for catalytic reforming is a petroleum fraction known as naphtha and having an initial boiling point of about 180° F. and an end boiling point of about 400° F. The catalytic reforming process is particularly applicable to the treatment of straight run gasolines comprised of relatively large concentrations of naphthenic and substantially straight chain paraffinic hydrocarbons, which are subject to aromatization through dehydrogenation and/or cyclization reactions.
Reforming may be defined as the total effect produced by dehydrogenation of cyclohexanes and dehydroisomerization of alkylcyclopentanes to yield aromatics, dehydrogenation of paraffins to yield olefins, dehydrocyclization of paraffins and olefins to yield aromatics, isomerization of n-paraffins, isomerization of alkylcycloparaffins to yield cyclohexanes, isomerization of substituted aromatics, and hydrocracking of paraffins. Further information on reforming processes may be found in, for example, U.S. Pat. No. 4,119,526 (Peters et al.); U.S. Pat. No. 4,409,095 (Peters); and U.S. Pat. No. 4,440,626 (Winter et al.).
A catalytic reforming reaction is normally effected in the presence of catalyst particles comprised of one or more Group VIII noble metals (e.g., platinum, iridium, rhodium, palladium) and a halogen combined with a porous carrier, such as a refractory inorganic oxide. The halogen is normally chlorine. Alumina is a commonly used carrier. The preferred alumina materials are known as the gamma, eta and theta alumina with gamma and eta alumina giving the best results. An important property related to the performance of the catalyst is the surface area of the carrier. Preferably, the carrier will have a surface area of from 100 to about 500 m 2 /g. The particles are usually spheroidal and have a diameter of from about 1/16th to about 1/8th inch (1.5-3.1 mm), though they may be as large as 1/4th inch (6.35 mm). In a particular regenerator, however, it is desirable to use catalyst particles which fall in a relatively narrow size range. A preferred catalyst particle diameter is 1/16th inch (3.1 mm). During the course of a reforming reaction, catalyst particles become deactivated as a result of mechanisms such as the deposition of coke on the particles; that is, after a period of time in use, the ability of catalyst particles to promote reforming reactions decreases to the point that the catalyst is no longer useful. The catalyst must be reconditioned, or regenerated, before it can be reused in a reforming process.
In preferred form, the reformer will employ a moving bed reaction zone and regeneration zone. The present invention is applicable to a moving bed regeneration zone and a fixed bed regeneration zone. Fresh catalyst particles are fed to a reaction zone, which may be comprised of several subzones, and the particles flow through the zone by gravity. Catalyst is withdrawn from the bottom of the reaction zone and transported to a regeneration zone where a hereinafter described multi-step regeneration process is used to recondition the catalyst to restore its full reaction promoting ability. Catalyst flows by gravity through the various regeneration steps and then is withdrawn from the regeneration zone and furnished to the reaction zone. Movement of catalyst through the zones is often referred to as continuous though, in practice, it is semi-continuous. By semi-continuous movement is meant the repeated transfer of relatively small amounts of catalyst at closely spaced points in time. For example, one batch per minute may be withdrawn from the bottom of a reaction zone and withdrawal may take one-half minute, that is, catalyst will flow for one-half minute. If the inventory in the reaction zone is large, the catalyst bed may be considered to be continuously moving. A moving bed system has the advantage of maintaining production while the catalyst is removed and replaced.
Referring to the drawing, the invention is illustrated in association with a section 10 of a cylindrical catalyst regeneration tower. Looking first at the flow of catalyst particles, upper nozzle 11 passes through the upper head 13 of regeneration tower 10. The upper nozzle 11 distributes catalyst particles generally uniformly through a plurality of conduits 12 into an upper annular catalyst particle bed 14 formed by an outer catalyst particle retention screen 18 and an inner catalyst particle retention screen 16. The upper annular catalyst particle bed 14, called the burn zone bed, is located above the elevation of a baffle 22, which is attached to the wall of the regeneration tower 10 and is located outside of the outer catalyst particle retention screen 18. The upper annular catalyst particle bed 14 discharges into a lower annular catalyst particle bed 21, which is located below the elevation of the baffle 22 and is also formed by the outer catalyst particle retention screen 18 and the inner catalyst particle retention screen 16. Baffle 22 segregates the gas streams that flow into and through the upper annular catalyst particle bed 14 and the lower annular catalyst particle bed 21, which is called the reheating zone bed. Burning of carbon off the catalyst particles occurs in the upper annular catalyst particle bed 14, and reheating the catalyst particles to the desired temperature for halogenation occurs after carbon burning and prior to halogenation in the lower annular catalyst particle bed 21.
In this embodiment, catalyst particle retention screens 16 and 18 ar cylindrical in form and concentric with the center line of regeneration vessel 10. Retention screens 16 and 18 are perforated with holes that are large enough to allow gas to pass through the annular catalyst bed but do not permit the passage of catalyst particles therethrough. Outer catalyst particle retention screen 18 extends downward from the bottom of conduits 12 to a swedge section 19 of regeneration vessel 10. Inner catalyst particle retention screen 16 is attached to the top head 13 of regeneration vessel 10 and extends downward therefrom to a point slightly above the lower end of outer catalyst particle retention screen 18. The bottom of the lower annular catalyst particle bed 21 is open to allow catalyst particles to empty from the catalyst bed into a halogenation zone bed 24 in a central portion of regeneration vessel 10. The annular catalyst bed transforms into a cylindrical shape as it passes into the halogenation zone bed 24.
Halogenation of the catalyst particles occurs in the halogenation zone bed 24. The upper portion of the bed 24 is formed by the wall of the regeneration vessel 10, and the lower portion of the bed 24 is formed by a baffle 26 that comprises an upper frusto-conical section and a lower vertical, cylindrical section. The lower portion of the bed 24 is open to allow catalyst particles to empty from the catalyst bed into a cylindrical bed 38, called the drying zone bed. In this embodiment, the catalyst particles reach cylindrical bed 38 from cylindrical bed 24 by passing through an annular bed 35 formed between an annular baffle 28 and a central baffle 34. Annular baffle 28 is cylindrical in form and concentric with the center line of regeneration vessel 10. Central baffle 34 comprises an upper conical section and a lower cylindrical section, and central baffle 34 is concentric with the center line of regeneration vessel 10. Horizontal conduits, not shown in the drawing, provide communication for gas between the annular space 36 and the space that is above the catalyst bed 38 and beneath the central baffle 34. These horizontal conduits do not significantly interfere with the flow of catalyst through the annular bed 35.
Drying of the catalyst particles occurs in the drying zone bed 38. The structural design of the bed 38 is in many respects the same as that of the bed 24. The upper portion of the bed 38 is formed by the wall of the regeneration vessel 10, and the lower portion of the bed 38 is formed by a baffle 42 that comprises an upper frusto-conical section and a lower vertical, cylindrical section. The lower portion of the bed 38 is open to allow catalyst particles to empty from the catalyst bed into a cylindrical bed 50, called the cooling zone bed. In this embodiment, the catalyst particles reach cylindrical bed 50 from cylindrical bed 38 by passing through an annular bed 45 formed between an annular 46 and a central baffle 44. Annular baffle 46 comprises an upper frusto-conical section and a lower vertical, cylindrical section, and annular baffle 46 is concentric with the center line of regeneration vessel 10. Central baffle 44 comprises an upper conical section and a lower cylindrical section, and central baffle 44 is concentric with the center line of regeneration vessel 10. Horizontal conduits, not shown in the drawing, provide communication for gas between the annular space 48 and the space that is above the catalyst bed 50 and beneath the central baffle 44. These horizontal conduits do not significantly interfere with the flow of catalyst through the annular bed 35.
Cooling of the catalyst particles occurs in the cooling zone bed 50. The structural design of the bed 50 is essentially the same as that of the bed 38. The upper portion of the bed 38 is formed by the wall of the regeneration vessel 10, and the lower portion of the bed 38 is formed by a baffle 52 that comprises an upper frusto-conical section and a lower vertical, cylindrical section. The lower portion of the bed 50 is open to allow catalyst particles to empty from the catalyst bed and into an outlet nozzle 104. The catalyst particles leave the regeneration tower 10 through a conduit 108. A temperature sensor/controller 106 measures the temperature of the catalyst particles in the conduit 108. The catalyst particles in the bed 50 are statically supported by catalyst particles that extend through the lower end closure 55 of regeneration tower 10 and through the conduit 108.
The catalyst particles are periodically transferred by withdrawing a predetermined volume of catalyst from the bed 50 through the conduit 108 which in turn allows all the catalyst particles to slump downward through the previously-described zones. Catalyst is withdrawn from conduit 108 at a rate that creates a 1.0 hour residence time for a particle to pass from the top of the cylindrical section of annular baffle 52 to the bottom of the cylindrical section of annular baffle 52. Only a matter of seconds or minutes are required for substantially complete heat transfer to occur. The residence time of 1 hour is a consequence of the vessel geometry required to get approximately uniform gas distribution when using an annular gas distribution baffle, such as annular baffle 52. Although other structure is preferably present above upper nozzle 11 and below the conduit 108, such structure has no bearing on the present invention and need not be described, except as already described as needed to statically support the catalyst particles in bed 50 and to periodically transfer catalyst particles from the regeneration vessel 10.
An important aspect of the present invention is that a controlled flow rate of cooled, dried air can be allowed to enter the cooling zone bed 50 through an inlet nozzle 94 in order to permit the hot catalyst particles which have descended into bed 50 from the bed 38 to be cooled to a desired degree. The source of air is preferably the plant supply of compressed air, which is generally produced by drawing air from the atmosphere, compressing to a convenient and elevated pressure, and cooling to a temperature less than about 100° F., which is lower than the temperature of the catalyst leaving the catalyst bed 38. Air dryer 96 removes water from the cooled air. Control over the total amount of cooled, dried air admitted is by means of a flow control valve 100 operated by a flow controller 98.
A first portion of the cooled, dried air enters inlet 94 in order to cool the catalyst in the bed 50. The cooled dried air that enters the bottom of the cooling bed 50 is generally at a temperature of between about 50° F. (10° C.) to about 100° F. (38° C.), or cooler. The pressure at the air inlet into the cooling bed 50 is generally between about 0 psig (0 kg/cm 2 g) to about 50 psig (3.5 kg/cm 2 g). Preferably, the pressure of the cooling bed 50 is any convenient pressure of the vessel with which it is associated, which, in this case, is the regeneration vessel 10. The pressure of the cooling bed 50 is generally not limited by cooling considerations, because heat transfer between solid particles and a gas is not strongly dependent on pressure. One skilled in the art is able to compute the heat transfer coefficient between the air and the catalyst particles for any pressure of the cooling bed 50. This first portion is preferably distributed downwardly through an annular chamber 54 that is defined by the annular baffle 52 and the wall of the regeneration vessel 10. At the bottom of the cylindrical section of the annular baffle 52, the cooling air reverses direction and flows nearly uniformly upwardly in a counterflow manner through the cooling zone bed 50. The ratio of the thermal flow rate of the cooling air to the thermal flow rate of the catalyst is less than 0.9 or greater than 1.15, and preferably it is less than 0.85 and greater than 1.20. The pressure difference from the bottom to the top of the cooling zone bed 50 that results from the flow of air is generally less than the average bulk density of the catalyst particles, and preferably less than one-half of the average bulk density of catalyst particles. The air that reaches the top of the cooling zone bed 50 exits through nozzle 86 and into a first conduit 88. From the previous description, catalyst particles reach cylindrical bed 50 from cylindrical bed 38 by passing through an annular bed 45, and some of the air that reaches the top of the cooling zone bed does flow through the annular bed 45 and into the cylindrical, drying zone bed 38. Preferably, however, the restriction to gas flow through the packed bed of catalyst in the annular bed 45 is relatively large in comparison to the restriction to the gas flow through the conduits 88, 90, the heater 84, the nozzle 82, and the annular chamber 40, none of which contain catalyst. So, most of the air that reaches the top of the cooling zone bed exits through the nozzle 86.
The air that exits the top of the cooling bed 50 is generally at a temperature of between about 980° F. (527° C.) to about 1020° F. (549° C.). Preferably, the temperature of the air that exits the cooling bed 50 is nearly at the temperature of the catalyst that enters the cooling bed 50. For example, the temperature of the exiting air may be within 1°-5° F. (1°-3° C.) of the entering catalyst particles. In general, the difference in temperature between the exiting air and the entering catalyst particles depends on the superficial velocity of the air through the cooling bed 50: the lower the velocity, the lower is the temperature difference, and likewise the higher the velocity, the higher is the temperature difference. The pressure of the air leaving the top of the cooling zone bed 50 is generally between about 1.0 psig (0.1 kg/cm 2 g) to about 50 psig (3.5 kg/cm 2 g), although, as described previously, the pressure is conveniently determined by the pressure of the regeneration tower 10. The air that exits through the nozzle 86 and into the conduit 88 combines with a second portion of the cooled, dried air. The second portion of the cooled, dried air stream is regulated by means of a flow control valve 92 operated by the temperature sensor/controller 106. The second portion combines with the air passing through the conduit 88, and the combined stream flows through the conduit 90 into an air heater 84. The heated, combined stream passes through a conduit and into the regeneration vessel 10 through the nozzle 82. Preferably, the air heater 84 is an electric air heater, and a temperature controller senses the temperature of the heated, combined stream that leaves the air heater 84 and adjusts an electric power control for the air heater 84.
The heated, combined air stream enters inlet 82 in order to dry the catalyst in the bed 38. The heated, combined stream that enters the bottom of the drying zone bed 38 is at a temperature that depends on the affinity of the catalyst particles for water, with a higher temperature generally being preferred for more drying when the catalyst's affinity for water is greater. Preferably, the heated, combined stream is at a temperature of between about 1000° F. (538° C.) to about 1050° F. (566° C.). The pressure in the drying zone bed 38 is generally between about 1.0 psig (0.1 kg/cm 2 g) to about 50 psig (3.5 kg/cm 2 g). In general, the pressure also depends on the affinity of the catalyst particles for water, with a lower pressure generally being preferred for more drying when the catalyst's affinity for water is greater. Preferably, however, the pressure of the drying zone bed 38 is determined by the pressure of the regeneration tower 10. The heated, combined air stream is preferably distributed downwardly through the annular chamber 40 that is defined by the annular baffle 42 and the wall of the regeneration vessel 10. At the bottom of the cylindrical section of the annular baffle 42, the heated, combined air stream reverses direction and flows nearly uniformly upwardly in a counterflow manner through the drying zone bed 38.
Most of the air that reaches the top of the drying zone bed 38 enters the annular space above the drying zone bed that is formed by the wall of the regeneration tower 10, a horizontal annular baffle 32, and the cylindrical baffle 28. A first portion of the air that reaches the top of the catalyst drying zone bed 38 passes through the horizontal, annular baffle 32, which is perforated with holes for gas flow, and into an annular chamber 30, which is defined by the wall of the regeneration tower 10 and the vertical, cylindrical baffle 28. A second portion of the air that reaches the top of the catalyst drying zone bed 38 is vented through nozzle 110. The amount of air which is vented through nozzle 110 is controlled by a valve 112. In principle, a third portion of air that reaches the top of the catalyst drying zone bed 38 could flow through the annular bed 35 and into the cylindrical, drying zone bed 38, since, as described above, catalyst particles reach cylindrical bed 50 from cylindrical bed 38 by passing through an annular bed 35. Preferably, however, the restriction to gas flow through the packed bed of catalyst in the annular bed 45 is relatively large in comparison to the restriction to the gas flow through the baffle 32, and the annular chambers 30 and 33, none of which contain catalyst. So, most of the air that reaches the top of the drying zone bed 38 exits either through the nozzle 110 or through the holes in the baffle 32.
The air which passes through the baffle 32 is combined with a halogenation agent in the annular chamber 30. The halogenation agent, such as an organic chloride, is generally supplied as a liquid by an injection pump from bulk containers of organic chloride, and such means are not an essential part of this invention. The liquid organic chloride passes through a conduit 76 and a steam heater 78 that vaporizes the organic chloride, which enters the regeneration tower 10 through the nozzle 80. In the annular chamber 30, the entering organic chloride vapor mixes with the upflowing air stream to produce the halogenation gas. At the top of the cylindrical baffle 28, the halogenation gas reverses direction and begins to flows downwardly through the annular chamber 33 that is defined by the baffles 28 and 26. At this point, the halogenation gas stream enters the catalyst bed 24 in essentially the same manner as the first portion of the air stream enters the catalyst bed 50. The halogenation gas is preferably distributed downwardly through the annular chamber 33. At the bottom of the cylindrical section of the annular baffle 26, the halogenation gas reverses direction and flows uniformly upwardly in a counterflow manner through the halogenation bed 24.
When the halogenation gas reaches the top of the bed 24, it will exit into an open chamber 23 defined by the inner wall of the screen 16 and at an elevation below the location of the baffle 22. As the halogenation gas moves up through open chamber 23, it will mix with the radially inwardly flowing flue gas exiting the screen 16. The flue gas exiting the reheating zone bed 21 has essentially the same oxygen content as the gas that enters the reheating zone bed 21. This is because essentially no combustion of coke occurs in the reheating zone bed 21, which has the purpose of only heating the catalyst exiting the burn zone bed 14.
The mixture of the halogenation gas and the flue gas exiting the reheating zone bed 21 move upward into a chamber 20, which is defined by the inner wall of the screen 16 and at an elevation above the location of the baffle 22. As the mixture moves upward through open chamber 20, it will mix with the radially inwardly flowing flue gas exiting the screen 16 above the baffle 22. The flue gas exiting the burn zone bed 14 has a relatively high temperature and substantially no oxygen content after having contacted the coke-covered catalyst within the burn zone bed 14. However, by mixing the gas mixture with the flue gas, a recycle gas mixture is produced. The recycle flue gas, which will have a variable oxygen content and a relatively high temperature, depending upon the portion of air in it, is delivered through the exit nozzle 60 and a conduit to a blower or fan 62.
The blower 62 forces a first portion of the recycled flue gas through a conduit 74 and an nozzle 76 into the regeneration tower 10 below the elevation of the baffle 22. This first portion, having a relatively high temperature, heats the reheating zone bed 21 containing catalyst after it has exited the bed 14 and before it enters the bed 24. The blower forces a second portion of the recycled flue gas through a conduit 64, a regeneration cooler 66, and an electric heater 68. The regeneration cooler 66 and the electric heater 68 operate in combination to ensure that the temperature of the gas entering the burn zone bed 14 is constant. In the event that the temperature of the recycle flue gas exceeds the desired inlet temperature, the regeneration cooler removes the heat of combustion from the second portion of the recycled flue gas by heat exchanging the recycled flue gas with atmospheric air. On the other hand, in the event that the temperature of the recycle flue gas is less than the desired inlet temperature, the electric heater 68 reheats the flue gas to the desired temperature. Preferably, a temperature controller senses the temperature of the recycled flue gas just before it re-enters the regeneration tower 10 through the inlet 72 and controls, as needed, either a regulating valve on the atmospheric air to the regeneration cooler 66 or the electric power control to the electric heater 68. The flue gas enters past an oxygen analyzer 70, and into the inlet nozzle 72 of the burn zone bed 14.
Assuming that it is desired that the recycle flue gas or combustion gas entering the nozzle 72 has an oxygen content of 0.8%, for example, a signal may be generated by the oxygen analyzer 70 to be used to control the operation of the valve 112 to vent a greater or lesser amount of the drying air in drying zone bed 38 through exit nozzle 1 10. The types of controls, analyzers, and valves used are conventional and will not be described here. Venting more air through nozzle 110 will decrease the amount left to exit through the baffle 32 and will therefore cause a decrease in the oxygen content of the recycle flue gas leaving the exit nozzle 60. Likewise, venting less air through exit nozzle 110 will increase the oxygen content of the recycle flue gas. In a typical situation, the amount of air required by the halogenation zone bed 24 and for combustion in the burn zone bed 14 might be only about 50% of that required by the drying zone bed 38. The remainder would be vented.
Assuming that it is desired that the catalyst exiting the regeneration tower through the nozzle 104 has a desired temperature of 400° F. (200° C.), for example, a signal may be generated by the temperature sensor/controller 106 to be used to control the operation of the valve 92 to bypass a greater or lesser amount of the cooled, dried air through regulating valve 92. The types of controls, sensors and valves used are conventional and will not be described here. Bypassing more air through regulating valve 92 will decrease the amount left to pass through the cooling zone bed 50 and will therefore cause an increase in the temperature of the catalyst leaving the exit nozzle 104. Likewise, bypassing less air through regulating valve 92 will increase the amount left to pass through the cooling zone bed 50 and will decrease the temperature of the catalyst leaving the exit nozzle 104.
The method of controlling the catalyst outlet temperature described in the preceding paragraph is particularly well-suited for when a sustained thermal flow ratio in the cooling zone bed 50 of equal to or less than 0.85 is desired. On the other hand, if a sustained thermal flow ratio greater than 1.2 is desired, an alternative method of control is as follows. The changes that are necessary to implement this control scheme can best be described by referring to the diagram. First, the temperature sensor/controller for the catalyst exiting through the conduit 108 is replaced with a temperature sensor/controller for the heated air stream exiting through the nozzle 86 or the conduit 88. Second, the regulating valve 92 is eliminated, along with the conduit that permits cooled, dried air to bypass the cooling zone bed 50. And third, the control of the regulating valve 100 by a signal from the flow controller 98 is replaced by a signal from the temperature sensor/controller for the heated air stream exiting the nozzle 86. Then, assuming that it is desired that the heated air stream exiting the regeneration tower 10 through the nozzle 86 has a desired temperature of 400° F. (200° C.), for example, a signal may be generated by the temperature sensor/controller to be used to control the operation of the valve 100 to permit a greater or lesser amount of the cooled, dried air through regulating valve 100. Again, the types of controls, sensors and valves used are conventional and will not be described here. Permitting more air through regulating valve 100 will increase the amount to pass through the cooling zone bed 50 and will therefore cause a decrease in the temperature of the air stream leaving the exit nozzle 86. Likewise, permitting less air through regulating valve 100 will decrease the amount to pass through the cooling zone bed 50 and will increase the temperature of the gas leaving the exit nozzle 86. Alternatively, excess air could be passed through the cooling bed zone, withdrawn from the cooling zone, and vented from the process if the temperature of the air at the outlet of cooling zone increases too high. A high gas outlet temperature indicates that the thermal ratio is decreasing towards 1.0.
A variation of the method of control described in the preceding paragraph is preferred when a sustained thermal flow ratio in the cooling zone bed 50 of greater than 1.2 is desired. Again, the changes that are necessary to implement this control scheme can best be described by starting with the diagram. First, the temperature sensor/controller for the catalyst exiting through the conduit 108 is replaced with a temperature sensor/controller for the heated air stream exiting through the nozzle 86 or the conduit 88. Second, the regulating valve 92 is eliminated, along with the conduit that permits cooled, dried air to bypass the cooling zone bed 50. Instead of valve 92 and its bypass conduit, a conduit is used to vent from the process a portion of the heated air stream in the conduit 88, and this vent conduit is equipped with a regulating valve. And third, the control of the regulating valve in the vent conduit is by a signal from the temperature sensor/controller for the heated air stream exiting the nozzle 86. Then, assuming that it is desired that the heated air stream exiting the regeneration tower 10 through the nozzle 86 has a desired temperature of 400° F. (200° C.), for example, a signal may be generated by the temperature sensor/controller to be used to control the operation of the regulating valve in the vent conduit to permit a greater or lesser amount of the heated air stream to vent from the process. Again, the types of controls, sensors and valves used are conventional and will not be described here. Permitting more air through regulating valve in the vent conduit will increase the amount to pass through the cooling zone bed 50 and will therefore cause a decrease in the temperature of the air stream leaving the exit nozzle 86. Likewise, permitting less air through the regulating valve in the vent conduit will decrease the amount to pass through the cooling zone bed 50 and will increase the temperature of the gas leaving the exit nozzle 86. In this manner, excess air may be passed through the cooling zone bed 50, withdrawn from the cooling zone, and vented from the process if the temperature of the air at the outlet of cooling zone increases too high. In this control arrangement, a high gas outlet temperature indicates that the thermal ratio of air to catalyst particles is approaching 1.0.
From the preceding description, it will be apparent that the flow rate of cooling air through the cooling zone bed 50 may be regulated at a thermal flow ratio of gas to solid that is not near 1, even though the rate of air that might otherwise be required for drying or for combustion in the regeneration tower 10 might be 1. The flow of cooling air which can enter the cooling zone 50 through the inlet 94 can be controlled completely independently of the control means for the drying air entering through the inlet 82, the drying air that exits the regeneration tower 10 through the nozzle 110, and the combustion air entering inlet nozzle 72. | A regeneration process is described that eliminates or greatly reduces thermal channelling in a cooling zone bed. The method controls the flow rate of cooling gas independently of the requirements of the regeneration process for combusting coke and for halogenating or drying the catalyst. In one embodiment, a portion of a cooling stream is bypassed around a cooling zone and then passed to a drying zone. In another embodiment, one portion of a cooling stream from a cooling zone is vented, and another portion of the stream is passed to a drying zone. | 1 |
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional application of U.S. application Ser. No. 12/310,146. The U.S. application Ser. No. 12/310,146 is the U.S. National Stage of International Application No. PCT/EP2007/057999 filed Aug. 2, 2007, and claims the benefit thereof. The International Application claims the benefits of European Patent Application No. 06017047.9 EP filed Aug. 16, 2006. All of the applications are incorporated by reference herein in their entirety.
FIELD OF INVENTION
[0002] The invention relates to a plain bearing which has a bearing body in which a body to be borne is borne, wherein the bearing body is surrounded by a supporting body.
BACKGROUND OF INVENTION
[0003] A plain bearing is a bearing in which the body which is rotating and is to be borne slides on sliding surfaces. In this case, the sliding surface of the body to be borne slides on the sliding surfaces of the bearing body. Depending on the nature of the plain bearing, the bearing body is designed differently. In the case of a radial plain bearing, the bearing body is in the form of a bearing shell which is embedded in a housing and may be subdivided into a plurality of bearing segments.
[0004] During operation of the plain bearing, the sliding surface of the body to be borne rubs on the sliding surfaces of the bearing body. In order to keep this friction, and therefore the wear of the plain bearing as well, as low as possible, a lubricant film, for example an oil film, is provided between the sliding surfaces.
[0005] When rotation starts, the lubricant is drawn into the gap between the sliding surfaces, and the body to be borne moves to an eccentric position in the bearing body. During this process, it passes through the range of mixed friction. As the sliding speed and the movement into the eccentric position increase, a lubricant wedge is formed between the body to be borne and the bearing body, whose pressure results in the body to be borne being lifted off the bearing body. The body to be borne then runs in a stable form in the bearing body, in the case of purely hydrodynamic lubrication without any direct contact between the bearing body and the body to be borne. This effect occurs in a radial plain bearing by a bearing clearance that is provided.
[0006] A plain bearing, in particular a radial plain bearing of the type mentioned initially, can be used, for example, in steam-turbine, generator and gas-turbine construction. In this case, the plain bearing bears rotor shafts as the bodies to borne.
[0007] The objective of current new developments in steam-turbine construction for electricity generation is to significantly increase the efficiency and to convert the energy efficiently. In this case, high operational reliability must be ensured, and cost savings must be achieved. As a result of this development:
a) the rotors are becoming longer, and the bearing separation is becoming greater, b) the evaporation cross sections are becoming greater, particularly in the low-pressure area, and c) the specific power of the individual turbine elements is increasing.
[0011] While at the same time maintaining a so-called mono block construction principle, particularly in the low-pressure area of steam turbines, this development is in the end leading to a significant increase in the specific bearing loads. The bearings and their maximum load-bearing capacity are therefore becoming limiting factors for turbine development, particularly in the low-pressure area. A similar development can also be observed in the case of generators and gas turbines. The load-bearing capacity of the plain bearings is limited by the maximum temperature, the maximum specific bearing load and the minimum lubricating film thickness.
[0012] In addition to the significant increase in the load-bearing capacity, this bearing is subject to the following additional requirements:
high stability for all load ranges, and good rotor-dynamic characteristics, maintenance friendliness, very high operating availability/low-wear operation, raising of the rotors by high-pressure oil during rotation high reliability (integrity of the turbine set with high unbalance levels), use in the existing bearing housing, and retrofit capability.
[0020] In order to comply with the abovementioned requirements and in order to significantly increase the load-bearing capacity of the plain bearings, the following measures, for example, are known:
reduction of the rotor weight, use of high-viscosity oils, greater bearing widths and/or bearing journal diameters, lower oil supply temperature, and directional (directed) lubrication (in the case of tilting pad bearings).
[0026] These standard measures to increase the load-bearing capacity have been proven in practice, but are reaching their limits ever more frequently.
SUMMARY OF INVENTION
[0027] An object of the invention is to improve a plain bearing of the type mentioned initially such that it complies with the requirements mentioned above for example for large-turbine construction, preferably for steam-turbine construction.
[0028] The object is achieved in that the bearing body is arranged as a multiple-surface bearing with its separating joint at an angle with respect to a horizontal.
[0029] It is advantageous for the bearing body to be formed from two half-shells, whose separating joint is arranged at an angle with respect to the horizontal.
[0030] It is expedient for the separating joint to be offset, seen in cross section, in the opposite direction to a rotation direction of the body to be borne or of a rotor shaft.
[0031] It is advantageous for the bearing body to be fixed with its separating joint in the angle position arranged with respect to the horizontal, wherein a fixing element, for example one or more pins, can be used for fixing, which fixing element is arranged in the supporting body and engages, for fixing purposes, in the bearing body, or rests on it for fixing purposes, such that the bearing body is held in its angle position in an adequately rotationally secure manner.
[0032] In a further advantageous refinement, the bearing body has a first channel, which is arranged at least in places, in its wall, seen in the circumferential direction, wherein at least one axial hole is arranged in the wall and passes through the first channel. This provides active cooling for the plain bearing and the bearing body.
[0033] In this case, it is expedient if the bearing body has at least one second channel which is at a distance from the first channel, seen in the axial direction, wherein at least one axial hole is arranged in the wall and passes through the first and the second channel, such that these channels are connected to one another via the axial hole. It is, of course, also possible to provide for a third or further channels to be provided, wherein the first channel is arranged between the second and third channel, seen in the axial direction, and wherein a plurality of axial holes are provided, which each pass through all three channels.
[0034] The first channel is advantageously incorporated in a loaded bearing shell of the bearing body and is open toward the supporting body, wherein the first channel is incorporated in a semicircular shape in the wall of the bearing body, seen in the circumferential direction, such that a semicircular groove is effectively formed which extends somewhat into the wall of an unloaded bearing shell, that is to say the second half-shell.
[0035] The first channel advantageously has bearing pockets at its opposite ends, seen in the circumferential direction, in each of which at least one injection element is arranged for injection of liquid lubricant, preferably of lubricating oil, to the body to be borne and to the rotor shaft.
[0036] The bearing body is advantageously in the form of a multiple-surface bearing composed of two half-shells, wherein the first channel is arranged in the loaded half-shell and extends at least at one end somewhat into the unloaded half-shell, wherein a separating joint of the multiple-surface bearing is arranged at an angle with respect to a horizontal, such that one of the bearing pockets is arranged above the horizontal, and the other bearing pocket is arranged below the horizontal, seen in cross section. By virtue of the configuration of at least the first channel, the bearing pockets are in this case arranged on the one hand in the loaded bearing shell and on the other hand in the unloaded bearing shell. The loaded bearing shell is that shell which absorbs the nominal load, while the role of the unloaded bearing shell is restricted predominantly to guiding the body to be borne in the bearing body.
[0037] In a further advantageous refinement, the bearing body is in each case arranged on its opposite bearing pockets, in the circumferential direction, with injection elements which are each arranged in a plurality of rows and spray liquid lubricant on the one hand onto the body to be borne and onto the rotor shaft and on the other hand into an outlet gap.
[0038] It is advantageous if the injection elements are arranged as a plurality of two rows in the respective bearing pockets, wherein the injection elements are screwed into the bearing pockets as nozzles.
[0039] In one preferred refinement, the injection elements and nozzles are arranged such that the required amount of oil or the required amount of liquid lubricant is sprayed at right angles onto the body to be borne or onto the rotor shaft, and on the other hand obliquely into the outlet gap of the loaded half-shell.
[0040] Overall, the invention preferably relates to radial plain bearings for rotating shafts with hydrodynamic lubrication. The shape of the hole in each bearing can be described by the horizontal displacement of two half-shells (cylindrical or profiled). In this case, the direction of the bearing separating joint in the case of split bearings is referred to as the horizontal. The bearing is suitable for only one rotation direction and therefore offers the advantage of the long, very slightly convergent, pulling-in gap, which results in broadening of the hydrodynamic pressure build-up.
[0041] Overall, this provides a better plain bearing which has adjustable injection lubrication (directed lubrication) for a completely surrounded plain bearing, in which case it is possible to dispense with hinged segments according to the prior art. In this case, fresh oil or the liquid lubricant is supplied through a hole, which is arranged on one side, through the supporting body (generally the housing) and first of all passes into a half-surrounded channel of the loaded half-shell, and then into the injection elements. A plurality of these are in each case arranged in two rows in the bearing pockets, or in the bearing pockets seen in the circumferential direction, and spray the amount of oil at right angles onto the body to be borne, or onto the rotor shaft, and obliquely into the outlet gap of the loaded half-shell. In this case, only the obliquely directed nozzles in one of the bearing pockets are active. This is preferably the bearing pocket which is arranged under the horizontal when the bearing body is in the fixed state. All the nozzles are screwed in, thus allowing metering of the oil throughput in the inlet.
[0042] Inlet wear and uncontrolled wear during operation are advantageously prevented by means of a supporting mirror. A channel (internal ring channel) which is closed in the width direction is arranged centrally and extends over the entire circumference of the unloaded half-shell.
[0043] Active cooling of the bearing is achieved by means of the preferably three channels that are provided, which extend in the circumferential direction, and by means of a plurality of axial holes in the loaded half-shell, wherein the liquid lubricant which is supplied through the hole, which is arranged at one end, in the supporting body first of all passes into the first channel and is then passed through each of the axial holes which are open to the other channels, as a result of which the loaded half-shell is actively cooled. The channels and axial holes therefore have a dual function. On the one hand, they are used for active cooling with fresh oil. On the other hand, they are used to supply fresh oil to the injection elements.
[0044] The plain bearing or the bearing body is advantageously turned into the supporting body in the opposite direction to the rotation direction of the body to be borne or the rotor shaft, and is held in an optimized angle position by the fixing element, to be precise the pin or pins. The angle position, to be precise the optimized angle position, is in this case different from one application to another, and can be calculated in accordance with the respective application.
[0045] This results in a plain bearing which has high stability over a wide load range and very good rotor-dynamic characteristics, with a very high load-carrying capacity as well, and at high circumferential speeds. Furthermore the plain bearing has a low friction power and low losses, and is distinguished by maintenance friendliness, because of the shell structure. In particular, the noticeable reduction in the friction power is achieved by the internal ring channel in the unloaded half-shell. It is particularly advantageous that the plain bearing can be used by virtue of the modular design in existing bearing housings and in existing installation conditions, with very high reliability. The plain bearing can be used in steam turbines, generators and/or for example gas turbines.
BRIEF DESCRIPTION OF THE DRAWINGS
[0046] Further advantageous refinements are disclosed in the dependent claims and in the following descriptions of the figures, in which:
[0047] FIG. 1 shows a cross section through a plain bearing,
[0048] FIG. 2 shows a longitudinal section through the plain bearing shown in FIG. 1 , and
[0049] FIG. 3 shows a graph, in which the (calculated) maximum lubricating film temperature is plotted against the specific bearing load.
DETAILED DESCRIPTION OF INVENTION
[0050] Identical parts are always provided with the same reference symbols in the various figures, as a result of which they are generally also described only once.
[0051] FIG. 1 shows a plain bearing 1 which, in the illustrated exemplary embodiment, is in the form of a radial plain bearing. The plain bearing 1 has a bearing body 2 in which a body 3 to be borne, which is referred to in the following text as a rotor shaft 3 , is borne. The bearing body is surrounded by a supporting body 4 , which is referred in the following text as a housing 4 .
[0052] The housing 4 has a horizontal 6 , with the direction of the bearing separating joint in the case of split bearings being referred to as the horizontal 6 .
[0053] The bearing body 2 is arranged as a multiple-surface bearing with its separating joint 7 at an angle with respect to the horizontal 6 .
[0054] A hole 8 , which is arranged at one end, is incorporated in the supporting body 4 or in the housing 4 . In the exemplary embodiment illustrated in FIG. 1 , this is arranged on the left-hand plane of the drawing, with the hole 8 being bisected by the imaginary horizontal 6 .
[0055] A fixing element 9 is arranged in the hole 8 such that the bearing body 2 can be fixed in its angular position. The fixing element 9 is, for example, in the form of a pin which engages in a corresponding receptacle in the bearing body 2 , as a result of which this is fixed such that it is sufficiently rotationally secure. FIG. 2 shows two high-pressure screw unions 25 which allow oil to be supplied at high pressure into hydrostatic pockets 29 for raising the rotor shaft.
[0056] In the illustrated exemplary embodiment, the bearing body 2 is composed of two half-shells 11 , 12 , with the bearing shell 11 being referred to in the following text as the loaded bearing shell 11 , and with the bearing shell 12 being referred to in the following text as the unloaded bearing shell 12 .
[0057] Three outer channels 13 , 14 , 16 ( FIG. 2 ) are arranged in the loaded bearing shell 11 and are open toward the housing 4 . A first channel 13 , which is illustrated in FIG. 2 , is in each case at a distance, seen in the axial direction, from the adjacent second channel 14 and third channel 16 , with the first channel 13 being arranged between the second and the third channel 14 and 16 , respectively.
[0058] Because of the chosen cross section, only the first channel 13 is illustrated in FIG. 1 . The first channel 13 is incorporated in the wall 17 of the loaded bearing shell 11 and extends in the rotation direction 18 of the body 3 to be borne, or of the rotor shaft 3 , somewhat beyond the separating joint 7 into the unloaded bearing shell 12 . Bearing pockets 19 and 21 are arranged at the opposite ends of the first channel 13 , seen in the circumferential direction, with the bearing pocket 19 being arranged in the loaded bearing shell 11 , and the bearing pocket 21 being arranged in the unloaded bearing shell 12 .
[0059] The second channel 14 and the third channel 16 are designed in a corresponding manner to the first channel 13 .
[0060] Longitudinal holes or axial holes 22 , which pass through the three channels 13 , 14 and 16 , are incorporated in the wall 17 in the area of the first channel 13 , and of the second and third channels 14 and 16 respectively.
[0061] Injection elements 23 , 24 , preferably nozzles, are arranged in the respective bearing pockets 19 and 21 , which are arranged at the end in the respective channels 13 , 14 and 16 , seen in the circumferential direction, which injection elements 23 , 24 in the preferred refinement on the one hand spray liquid lubricant or lubricating oil at right angles (injection element 23 ) onto the body 3 to be borne or onto the rotor shaft 3 , and on the other hand obliquely (injection element 24 ) into an outlet gap 26 of the loaded half-shell 11 and of the unloaded half-shell 12 , respectively. In this case, only the injection elements 23 or nozzles which are directed at right angles in the bearing pocket 21 are not active.
[0062] In the exemplary embodiment illustrated in FIG. 1 , the bearing body 2 is shifted with its separating joint 7 out of the horizontal 6 , in the opposite direction to the rotation direction 18 . The bearing body 2 is therefore arranged with its separating joint 7 at an angle with respect to the horizontal 6 , wherein an angle a may have a different magnitude from one application to another, and can be determined and/or calculated separately for each specific application.
[0063] Fresh lubricant or oil is supplied through the hole 8 , which is arranged at one end, in the supporting body 4 or in the housing 4 , and is first of all passed into the half-surrounded first channel 13 of the loaded half-shell 11 , and then into the injection elements 23 and 24 , respectively. A plurality of these are in each case arranged in two rows in the respective bearing pockets 19 and 21 , and spray the required amount of oil at right angles onto the rotor shaft 3 and obliquely into the outlet gap 26 of the loaded half-shell 11 . All of the injection elements 23 , 24 or nozzles are preferably screwed into the respective bearing pockets 19 or 21 , thus allowing metering of the oil throughput in the inlet.
[0064] An internal ring channel 31 is arranged approximately centrally in FIG. 2 and is closed in the width direction, extending over the entire circumference of the unloaded half-shell 12 .
[0065] By way of example, FIG. 3 shows the (calculated) maximum lubricating film temperature (T max [° C.]) plotted against the specific bearing load (p lat [N/mm 2 ]). In this case, a temperature/load characteristic of a conventional plain bearing (reference symbol 27 ) is illustrated in comparison to a temperature/load line (reference symbol 28 ) of the plain bearing designed according to the invention, or radial plain bearing with hydrodynamic lubrication. The graph in FIG. 3 clearly shows that the plain bearing according to the invention is subject to considerably lower temperatures for the same load. | A plain bearing includes a bearing body in which a body, which is to be stored, is arranged. The bearing body is surrounded by a supporting body. The bearing body has a partial joint arranged at an angle in relation to the horizontal. The plain bearing has an active cooling system and an articulated lubrication system. | 5 |
CROSS-REFERENCE TO RELATED PATENTS
The following coassigned patent applications are hereby incorporated herein by reference:
______________________________________ Pat. No. Filing Date______________________________________ 5,096,279 Nov. 26, 1990 5,083,857 Jun. 29, 1990______________________________________
FIELD OF THE INVENTION
This invention relates to digital micro-mirror devices (DMD's), also known as deformable mirror devices, and more particularly to an addressing arrangement for such devices.
BACKGROUND OF THE INVENTION
DMD's have found numerous applications in the areas of optical information processing, projection displays, and electrostatic printing. See references cited in L. Hornbeck, 128×128 Deformable Mirror Device, 30 IEEE Tran. Elec. Dev. 539 (1983).
A great number of the applications described in Hornbeck, supra, use DMD's operated in a bistable mode as described in U.S. Pat. No. 5,096,279, incorporated by reference herein. The details of '279 will be summarized in some detail herein, but briefly in the bistable mode of a DMD a deflectable beam or mirror may be deflected to one of two landing angles, ±θ L , by underlying electrodes to which an address voltage is applied. At either landing angle (±θ L ) an extremity of the deflectable mirror lies in contact with an underlying device substrate.
With further reference to '279, in order to lower the address voltage requirement, a bias voltage is applied to the mirror relative to the address electrodes. The bias voltage serves to create energy potential minima. The amount of bias determines whether the deflectable mirror and its associated address and bias circuitry operated in a monostable, tristable, or bistable mode corresponding respectively to one, three, or two energy potential minima. The required address voltage also varies with the amount of bias, and typically the bias voltage is chosen such that the address voltages may operate with 5 V CMOS limits. For example, a typical bistable DMD operated with no bias requires a 16 volt address. At a bias of -10 V the DMD is operating in the tristable mode and requires a +10 V address. At a bias of -16 V the DMD is operating in the bistable mode and requires only a +5 V address. It is clear in this example, that to be compatible with standard 5 V CMOS address circuitry, it is necessary to operate in the bistable mode, which requires bidirectional operation and addressing. When the bias voltage is applied to the deflectable mirror, further changes in the address electrodes within normal operating limits cause no change in state of the deflectable mirror because the address voltage is not sufficient to overcome the potential energy barrier between the stable state in which the mirror resides and the other stable state which exists in a bistable mode. In order to change stable states it is necessary to remove the bias voltage to allow the deflectable mirror to respond to the voltage of the address electrode.
It has been discovered with prior art DMD's that when a deflectable mirror is deflected and in contact with the landing pads on the DMD substrate, it is necessary to apply a high voltage, high frequency resonant reset sequence to allow the mirror's addressed state to change. The reset sequence was adopted to overcome sticking difficulties caused by Van der Waal's forces or surface contamination. These sticking difficulties cause the beam to resist changing states regardless of the condition of the address electrodes underneath the beam.
SUMMARY OF THE INVENTION
The present invention recognizes that the longer the mirror and the landing electrode are in contact in an uninterrupted fashion, the higher the reset voltage must be to release the pixel. The amount of time the mirror and the landing electrode are in contact in an uninterrupted fashion shall be referred to as the residence time. Typical reset voltages are in the range of 12-25 V for residence times ranging from milliseconds to seconds. The present invention seeks to minimize the residence time thereby reducing the required reset voltages or eliminating the high voltage, high frequency, resonant reset altogether.
As such, a preferred embodiment of the present invention superimposes an AC signal onto the normal DC bias signal described above. In this manner it is possible to tilt the mirror to its full deflection (±θ L ) without having prolonged, uninterrupted contact with the underlying DMD substrate. By defining the AC signal to have a relatively small amplitude, the optical performance of the micromirror is unaffected, as the small superimposed mirror deflections are insignificant with respect to the addressed deflection to the mirror landing angle (±θ L ). Still, the AC signal may be defined to have a large enough amplitude to periodically interrupt contact between the mirror and the DMD substrate preventing formation of chemical bonds and condensation of moisture which can cause the sticking between the mirror and the DMD substrate.
The preferred embodiment provides a method of addressing a digital micromirror device (DMD) having an array of electromechanical pixels comprising deflectable beams wherein each of the pixels assume one of two or more selected stable states according to a set of selective address voltages. A first step of the preferred method is electromechanically latching, by applying a bias voltage with an AC and DC component to the array of pixels, each of the pixels in one of the selected stable states. A second step is applying a new set of selective address voltages to all the pixels in the array. A third step is electromechanically unlatching, by removing the bias voltage from the array, the pixels from their previously addressed state. A fourth step is allowing the array of pixels to assume a new state in accordance with the new set of selective address voltages. A fifth step is electromechanically latching, by reestablishing the bias voltage with the AC component and the DC component, each of the pixels.
The elimination of the high voltage, high frequency resonant reset circuitry and associated switching devices represents a considerable system simplification and cost reduction without degradation in performance. Indeed performance should be slightly improved, as the time taken for application of the reset sequence would be eliminated and can be applied to displaying data.
BRIEF DESCRIPTION OF THE DRAWINGS
For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:
FIGS. 1a-c illustrate in perspective, cross sectional elevation, and plan views, a functional rendering of a preferred embodiment pixel;
FIG. 2 illustrates deflection of a mirror of the preferred embodiment;
FIGS. 3a-c illustrate a prior art method of a high voltage, high frequency, resonant reset for a prior art DMD;
FIG. 4 illustrates a bias method for the mirror of the preferred embodiment which eliminates the need for a high voltage, high frequency, resonant reset;
FIGS. 5a-c schematically illustrate use of the preferred embodiment DMD for electrophotographic printing;
FIG. 6a illustrates a top view of a partial array of preferred embodiment mirrors;
FIG. 6b illustrates a top view of a preferred embodiment mirror showing major hidden features;
FIG. 6c illustrates a detailed cross sectional view as indicated in FIG. 6b of a preferred embodiment mirror; and
FIGS. 7a-d illustrate, in partial cross section, progressive formation of a mirror of the preferred embodiment.
Corresponding numerals and symbols in the different figures refer to corresponding parts unless otherwise indicated.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
FIGS. 1a-c illustrate in perspective, cross sectional elevation, and plan views a functional rendering of a preferred embodiment mirror. As illustrated by these figures, pixel 20 is operated by applying a voltage between beam 30 and electrodes 42 or 46 on substrate 22. Beam 30 and the electrodes form the two plates of an air gap capacitor and the opposite charges induced on the two plates by the applied voltage exert electrostatic force attracting beam 30 to substrate 22, whereas electrodes 40 and 41 are held at the same voltage as beam 30. The electrostatic force between electrodes 42,46 and beam 30 causes beam 30 to twist at hinges 34 and 36 and be deflected towards substrate 22.
FIG. 2 is a schematic view of the deflection of beam 30 with an indication of the charges concentrated at the regions of smallest gap for a positive voltage applied to electrode 42. For voltages in the range of 20 to 30 volts, the deflection is in the range of 2 degrees. Of course, if hinge 34 were made longer or thinner or narrower, the deflection would increase as the compliance of hinge 34 varies linearly with the inverse of its width and directly with the square of its length and inversely with the cube of its thickness. For a DMD operating in its bistable mode, the beam design is such that the beam's 30 deflection is defined by the landing angles, ±θ L , at which point the beam 30 contacts the DMD substrate on landing electrodes 40,41. Note that the thickness of beam 30 prevents significant warping of beam 30 due to surface stress generated during processing, but that the thinness of hinge 34 allows for large compliance. FIG. 2 also indicates the reflection of light from deflected beam 30 as may occur during operation of the DMD.
FIGS. 3a-c illustrate a prior art reset method which uses a pulse train of five reset pulses. A typical waveform of this prior art method is illustrated in FIG. 3a. The use of a pulse train in this prior art method allowed the frequency of the pulse train to be adjusted. In particular, if the pulse train frequency is near the resonant frequency for the torsion hinge flexure (nonrotational bending), then maximum energy is transferred into the flexure mode, and a smaller reset voltage may be used. FIG. 3b illustrates the minimum voltage needed for reset as a function of frequency for the prior art pulse train reset applied to a particular DMD having a linear array of 840 pixels with each pixel similar to the first preferred embodiment. FIG. 3c illustrates the effect of the number of pulses in the reset pulse train when the frequency of the pulses is at a resonant frequency. The minimum reset voltage decreases as the number of pulses is increased to five, and beyond five pulses no further decrease is observed. Apparently, with more than five pulses the kinetic energy is large enough that the energy losses due to air damping just balances the energy gained for each additional pulse. Note that while this prior art reset method reduced the minimum reset voltage to approximately 20 V, difficulties exist in constructing circuitry to generate a high voltage, high frequency resonant reset pulse train.
FIG. 4 illustrates the biasing method of the present invention which obviates the reset pulses and circuitry of prior art devices. U.S. Pat. No. 5,096,279, incorporated by reference herein, discloses the addressing and biasing scheme of a typical bistable DMD in great detail. To summarize, a bistable pixel 20 can be made addressable by establishing a preferred direction for rotation. If both address electrodes 42 and 46 are grounded, then small perturbations will cause beam 30 to randomly rotate and collapse to one of the landing electrodes 40,41 upon application of the differential bias V B to beam 30 and landing electrodes 40 and 41. However, if prior to application of the differential bias V B , address electrode 46 is set to a potential then a net torque will be produced to rotate beam 30 towards landing electrode 41. Symmetrically, applying the triggering potential to address electrode 42 will rotate beam 30 to landing electrode 40 upon application of the differential bias V B .
Referring still to FIG. 4, the preferred embodiment of the present invention superimposes an AC signal onto the normal DC bias signal, V B , described above. This AC signal has a small amplitude, V 1 , which may be varied for optimal performance. Of course, other signal shapes (such as sine wave or triangular) may be used. As long as V B is maintained, beam 30 remains in a stable state regardless of the state of the address electrodes (as long as the voltage applied to address electrodes 42,46 is insufficient to overcome the potential well in which the beam is held by the bias voltage V B ). In this manner it is possible to tilt the beam or micromirror 30 to its full deflection (±θ L ) without having prolonged, uninterrupted contact with the underlying DMD substrate. By defining the AC signal to have a relatively small amplitude, V 1 , the optical performance of the micromirror 30 is unaffected, as the small superimposed micromirror 30 deflections are insignificant with respect to the addressed deflection to the mirror landing angle (±θ L ). Still, the AC signal may be defined to have a large enough amplitude, V 1 , to periodically interrupt contact between the mirror and the DMD substrate, preventing formation of chemical bonds and condensation of moisture which can cause the sticking between the micromirror 30 and the DMD substrate. The period of this AC signal, τ r , is preferably the inverse of the resonant frequency for the torsion hinge flexure (nonrotational bending) which in the preferred embodiment is about 0.2 μs. Upon completion of a video frame period, τ f , the bias voltage V B is removed from the beam 30 and the beam 30 is set to zero potential initiating a mirror unlatching time period, t 1 . During this period, t 1 , the beams 30 assume neutral positions. Optionally, an AC signal may still be applied during unlatching time period, t 1 , to act as a low voltage reset pulse train. Again, the amplitude, V 2 , and period of this AC signal may be adjusted for best operation. Preferably the period of this signal is τ r . After a sufficiently long period, approximately 12 to 15 μs in a preferred embodiment, the bias voltage V B is reapplied to the beam 30 and landing electrodes 40,41. For a mirror latching time period, t 2 , the mirrors assume their new positions. After latching time period, t 2 , which is typically approximately 12 to 15 μs, the mirrors have settled into their newly addressed positions and new data may be addressed upon the DMD. During mirror latching time period, t 2 , the AC signal may or may not be applied (if mirror latching time period is reasonably short). During the remainder of video frame period, τ f , the pixels 20 are held in their stable states as established during the previous video frame, while new data is updated and placed on address electrodes 42,46.
Additional advantages of minimizing or eliminating the reset voltage include a minimizing of the possibility of dielectric failure on the DMD chip and a reduction in power supply complexity. As previously mentioned, the elimination of the high voltage, high frequency resonant reset circuitry and associated switching devices represents a considerable system simplification and cost reduction without degradation in performance. Indeed performance should be slightly improved, as the time taken for application of the reset sequence would be eliminated and can be applied to displaying data.
A linear array 310 of preferred embodiment pixels 20 could be used for electrophotographic printing as illustrated schematically in FIGS. 5a-c. FIG. 5a is a perspective view and FIGS. 5b-c are elevation and plan views showing system 350 which includes light source and optics 352, array 310, imaging lens 354 and photoconductive drum 356. The light from source 352 is in the form of a sheet 358 and illuminates linear array 310. Light from the areas between pixels 20 forms sheet 360 which is the specularly reflected sheet of light. The light reflected from negatively deflected beams form sheet 361. The light reflected from positively deflected beams 30 pass through imaging lens 354 within sheet 362 and focus on drum 356 within line 364 as a series of dots, one for each deflected beam 30. Thus a page of text or a frame of graphics information which has been digitized and is in raster-scanned format can be printed by feeding the information a line at a time to array 310 to form dots a line 364 at a time on drum 356 as drum 356 rotates. These dot images are transferred to paper by standard techniques such as xerography. If 0 is the deflection angle of beam 30 when on landing electrodes 41, then sheet 362 is normal to linear array 310 when the angle of incidence of sheet 358 is 20° from the normal to linear array 310. This geometry is illustrated in FIG. 5b and permits imaging lens 354 to be oriented normal to linear array 310. Each positively deflected beam produces an image 355 of light source 352 on imaging lens 354 as schematically shown in FIG. 5c for three beams.
FIGS. 6a-c illustrate a top view, a top view showing major hidden features, and a detailed cross section of a partial array of preferred embodiment mirrors. This preferred embodiment structure uses a multi-level deformable mirror structure and method of manufacturing as disclosed by Hornbeck in U.S. Pat. No. 5,083,857. As shown in FIG. 6a, this structure provides a greatly improved area of rotatable reflective surface for a given pixel size. The underlying hinges, address and landing electrodes are shown as dotted lines in FIG. 6b. Beam support post 201 rigidly connects beam 200 to underlying torsion hinge 401. Details of the underlying hinge and electrodes are shown in FIG. 6b. Beam support post 201 allows beam 200 to rotate under control of hinges 401 which in turn are connected to posts 406. This allows rotatable surface (beam) 200 to rotate under control of an electrode supported by posts 403. Beam 200 lands in contact with landing electrode 405. Contact 402 extends through the substrate and is in contact with the underlying address electronics. The construction and operation of this device will be discussed hereinafter. FIG. 6c illustrates beam 200 rotation 200a to landing angle -θ L and rotation 200b to landing angle +θ L . Also shown are address electrodes 404 which control the movement (200a, 200b) and landing electrodes 405 positioned at the other end of the see-saw swing of beam 200. The manner of controlling the rotational movement of beam 200 is detailed in U.S. Pat. No. 5,096,279 filed on Nov. 26, 1990.
The process sequence for the hidden hinge architecture is shown in FIGS. 7a-7d and consists of five layers (hinge spacer, hinge, electrode, beam spacer, and beam). Referring now specifically to FIG. 7a, the process begins with a completed address circuit 503 including contact openings formed in protective oxide 501 of the address circuit. The address circuit is typically a two metal layer/poly CMOS process. The contact openings allow access to the second level metal (METL2) 502 bond pads and to the METL2 address circuit output nodes.
Still referring to FIG. 7a, hinge spacer 701 is spin-deposited over the address circuit and patterned with holes 702 that will form the hinge support posts and electrode support posts and contacts. This spacer is typically 0.5 μm thick and is a positive photoresistant deep UV hardened to a temperature of 200° C. to prevent flow and bubbling during subsequent processing steps.
As shown in FIG. 7b, the next two layers 703 and 704 are formed by the so-called buried hinge process. An aluminum alloy that forms the hinge is sputter-deposited onto the hinge spacer. This alloy is typically 750 Å thick and consists of 0.2% Ti, 1% Si and the remainder Al. A masking oxide is plasma-deposited and patterned in the shape of hinges 401. This hinge oxide is then buried by a second aluminum alloy layer 704 that is to form the electrode (typically 3000 Å thick).
With further reference to FIG. 7b, a masking oxide is plasma-deposited and patterned in the shape of the electrodes 404, the electrode support posts 406 and the beam contact metal 405. Next, a single plasma aluminum etch is used to pattern the hinges, electrodes, support posts and beam contact metal. The electrode metal overlying the hinge region is etched away, exposing the buried-hinge oxide which acts as an etch stop. When the plasma aluminum etch is complete, regions of thin hinge metal 703 and thick electrode metal 704 have been simultaneously patterned. The masking oxide is then removed by a plasma etch.
Next as shown in FIG. 7c, beam spacer 705 is spin-deposited over the hinges and electrodes and patterned with holes that will form beam support posts 201. Spacer 705 determines the torsion beam angular deflection and is typically 1.5 microns thick and is a positive photoresistant. It is deep UV hardened to a temperature of 180° C. to prevent flow and bubbling during subsequent processing steps. Note that no degradation of hinge spacer 701 occurs during this bake, because the hinge spacer was hardened to a higher temperature (200° C.). Next, an aluminum alloy that is to form beam 200 (typically 4000 Angstroms thick) is sputter-deposited onto beam spacer 705. Next, masking oxide 707 is plasma-deposited and patterned in the shape of the beams. The beam is then plasma etched to form the beams and beam support posts. This completes the process at the wafer level. Masking oxide 707 on beam 200 is left in place. The wavers are then coated with PMMA, sawed into chip arrays and pulse spin-cleaned with chlorobenzene. Finally, the chips are placed in a plasma etching chamber, where masking oxide 707 is removed and both spacer layers 701 and 705 are completely removed to form the air gaps under the hinges and beams as shown in FIG. 7d.
Although this description describes the invention with reference to the above specified embodiments, the claims and not this description limited the scope of the invention. Various modifications of the disclosed embodiment, as well as alternative embodiments of the invention, will become apparent to persons skilled in the art upon reference to the above description. Therefore, the appended claims will cover such modifications that fall within the true scope of the invention.
A few preferred embodiments have been described in detail hereinabove. It is to be understood that the scope of the invention also comprehends embodiments different from those described, yet within the scope of the claims. Words of inclusion are to be interpreted as nonexhaustive in considering the scope of the invention. Implementation is contemplated in discrete components or fully integrated circuits in silicon, gallium arsenide, or other electronic materials families, as well as in optical-based or other technology-based forms and embodiments. It should be understood that various embodiments of the invention can employ or be embodied in hardware, software or microcoded firmware.
While this invention has been described with reference to illustrative embodiments, this description is not intended to be construed in a limiting sense. Various modifications and combinations of the illustrative embodiments, as well as other embodiments of the invention, will be apparent to persons skilled in the art upon reference to the description. It is therefore intended that the appended claims encompass any such modifications or embodiments. | A preferred embodiment of the present invention provides a method of addressing a digital micromirror device (DMD) having an array of electromechanical pixels (20) comprising deflectable beams (30) wherein each of the pixels (20) assume one of two or more selected stable states according to a set of selective address voltages. A first step of the preferred method is electromechanically latching, by applying a bias voltage with an AC and a DC component to the array of pixels (20), each of the pixels (20) in one of the selected stable states. A second step is applying a new set of selective address voltages to all the pixels (20) in the array. A third step is electromechanically unlatching, by removing the bias voltage from the array, the pixels (20) from their previously addressed state. A fourth step is allowing the array of pixels (20) to assume a new state in accordance with the new set of selective address voltages. A fifth step is electromechanically latching, by reestablishing the bias voltage with the AC component and the DC component, each of the pixels (20 ). Other devices, systems and methods are also disclosed. | 8 |
[0001] This application claims priority to PCT/US2004/040458, filed Dec. 2, 2004, which claims priority to U.S. 60/526,471, filed Dec. 2, 2003.
BACKGROUND
[0002] This invention relates to biocompatible implants, and in particular to implants that promote the growth and attachment of tissue to the implant Biocompatible implants are commonly used to secure or to replace bone structures in humans and animals. Implants used to maintain and extend the functionality of limbs, joints, and dental functions are typically made from corrosion resistant metal materials, such as stainless steels, cobalt-chromium molybdenum alloys, or titanium alloys. They are commonly applied to hips, knees, shoulders, hands, jaws, and other areas where stabilization may be required, such as vertebra segments or support rods for the backbone. In other applications implants are used to reinforce or reshape vascular structures such as aneurisms. Advancements in implant technology have included the development of coatings for implants that improve the ability of the body to accept the implant, as well as the ability to accelerate the growth and attachment of body tissues onto the implant. Typical approaches employed include the attachment to the implant surface of high surface area metal beads or high surface area hydroxyapatite (HA), which is the chemical equivalent of bone onto the implant. Typical approaches employed include the attachment to the implant surface of high surface area metal beads, or high surface area hydroxyapatite (HA), which is the chemical equivalent of bone. These surface coatings provide both chemical compatibility, as well as a textured surface onto which the body tissues can firmly attach.
[0003] While these advancements have reduced the rejection rate of implants in human and animal recipients, they also suffer from metallurgical property shortcomings that result in premature failure of the implant, rejection by the recipient, and/or damage to the surrounding bone and tissue in the recipient. There are several major shortcomings of current technologies.
[0004] In the case of high surface area metal surfaces, such as titanium spheres that are sintered onto the implant, the issue is that of tissue compatibility. Even if tissue grows into the porous structure provide by the coating, the bond between the tissue and the titanium coating is strictly mechanical rather than biological. Because the bone tissue sees the metal surfaces as a “foreign” material, de-bonding occurs over time, and the implant fails to perform according to design.
[0005] Another shortcoming of the prior art is that surface coatings of metal or HA are mechanically bonded to the underlying implant surface. Over time the surface coatings de-bond from the implant body. Debonding of the implant coatings causes mechanical failure of the implant and/or rejection of the implants.
[0006] Finally, most mechanically bonded metal and HA coatings applied today are the result of either thermal spray technology or a sintering process, both of which expose the base metal (or implant) to high temperatures. This exposure can result in the formation of a heat affected zone (HAZ) within the base metal or implant. An HAZ can result in premature fatigue cracking of the implant, as can compromise other important properties of the implant such as tensile strength and Young's Modulus.
[0007] In any of the above, the result is often the premature failure of the implant and premature replacement surgery, exposing the patient to the inherent risks, expense and inconvenience of additional surgery. Clearly, technological advances in this area that could improve the bond of surface layers to the body of the implant while at the same time enhancing the growth and attachment of tissue to the implant would represent a major improvement in implant technology.
SUMMARY OF THE INVENTION
[0008] This invention provides improved biocompatible implants that exhibit improved structural integrity when compared to known implants, and that accelerate the growth and attachment of body tissues to the implant. The invention is embodied in implant devices that include an underlying structure and a surface layer deposited on the underlying structure by a method known as fusion surfacing.
[0009] Pulse fusion surfacing (PFS) refers to a pulsed-arc micro-welding process that uses short-duration, high current electrical pulses to deposit an electrode material onto a metallic substrate. PFS allows a fused, metallurgically bonded coating to be applied with a sufficiently low total heat output so that the bulk substrate material remains at or near ambient temperatures. The short duration of the electrical pulse allows an extremely rapid solidification of the deposited material and results in a fine-grained, homogeneous coating that approaches an amorphous structure. The process has been used in the past to apply wear and corrosion resistant surfaces on materials used in harsh environments. Alternative coatings have been used to alter the substrate surface resistance to wear and corrosion.
[0010] PFS is generally described in U.S. Pat. No. 5,448,035 to Thutt, Kelley et al., which is hereby incorporated by reference in its entirety. In general, PFS is a welding method in which very small, pulsed electrical currents are discharged through an electrode into a workpiece, in this instance an implant. The current pulses melt small portions of the electrode and at the same time heat and melt a very thin layer of a small portion of the surface. The molten electrode material is welded to the surface while the workpiece remains largely unaffected since the current pulses are so small. The result is a very thin layer of alloy “welded” to the surface of the workpiece. The alloy can be chosen to provide wear resistance, chemical resistance, surface hardness or any of a number of desired properties. In a PFS process both the electrode and the workpiece (i.e., substrate) are conductive and form the terminal poles of a direct current power source. When a high surge of energy is applied to the electrode, a spark is generated between the electrode and the substrate. While not known for sure, it is generally assumed that a gas bubble forms about the spark discharge from the electrode and persists for a time longer than the spark itself. Metal melted due to the high temperature of the spark is then transferred from the electrode to the substrate surface via the expanding gas bubble. Alternatively, the polarities between the electrode and the substrate can be reversed so that metal can be transferred from the substrate to the electrode.
[0011] The PFS surface layer as used in the present invention is formed of any of a number of metallic or ceramic alloys, or can be formed of the same material as the implant or workpiece. The PFS surface layer according to this invention includes one or more tissue growth-enhancing elements such as calcium or phosphorous integrated into the PFS-formed surface layer, and which stimulate tissue growth and attachment to the PFS-applied surface layer. The PFS layer of the present invention is applied by a novel method in which the underlying structure is immersed in a liquid bath containing one or more dissolved tissue growth enhancing elements. The PFS layer can be tailored in both composition and surface morphology to provide any number of properties as is described in the prior art. In addition, however, this invention provides a significant additional feature that has heretofore not been possible. In this invention the PFS layer is applied with the electrode and workpiece submerged in a liquid bath. The liquid bath contains one or more tissue-growth enhancing elements or compounds in solution or in suspension that are integrated into the PFS layer as it is applied to the workpiece. The tissue-growth enhancing elements promote the growth and attachment of tissue to the implant, leading to a more reliable and durable treatment when implants are required.
[0012] The invention is embodied in orthopedic implants such as hip and knee implants, spinal inserts, orthopedic and dental attachment devices such as screws and wires, cardiac devices, and vascular implants such as vascular occlusive devices used to treat aneurysms. This list is intended to be inclusive and not exhaustive.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a schematic view of a processing bath according to the invention.
DESCRIPTION OF THE INVENTION
[0014] Preferred embodiments of the invention will now be described in greater detail by reference to the drawings and several examples.
EXAMPLE 1
[0015] In one example, a liquid bath ( FIG. 1 ) was made from a mixture of 69 grams of distilled water, 10 grams of calcium carbonate, and 82 grams of phosphoric acid (H3PO4), and 52 grams of calcium phosphate (monobasic monohydrate). A sample disc of Ti-6Al-4V was submerged in the bath, grounded to the PFS circuit, and supported by a non-conductive polymeric support. A stream of argon was bubbled into the bottom of the bath for agitation. A suitable PFS system is currently made and sold by Advanced Surfaces and Processes, Inc., assignee of the present invention. A PFS electrode of the same alloy was connected to the PFS apparatus, and placed in operative proximity to the sample. A relatively low energy PFS process was then conducted for about 3 minutes during which current was passed through the electrode and into the sample. The sample was then removed from the bath, ultrasonically cleaned, and analyzed by Energy-Dispersive X-Ray Spectroscopy (EDX) for calcium and phosphorous content. The PFS-applied layer included 0.34 atomic % calcium and 1.54 atomic % phosphorous. The sample was then tested for tissue-growth enhancement.
[0016] Primary rat osteoblasts were seeded onto the sterile surface of the sample and onto the sterile surface of an unmodified Ti-6Al-4V sample by placing each sample into a well containing 10,000 cells per disc in a 100 milliliter volume of tissue culture media (alpha MEM, supplemented with 5% FBS, (Gibco). Following a 1, 4 and 7 day culture period, attachment and proliferation was measured with the metabolic indicator Alamar Blue (Biosource International, Camarillo, Calif.). Alamar blue is a non-destructive oxidation-reduction calorimetric indicator that enables repeated analysis of each sample over several intervals. The cell culture medium was removed from each well and was replaced with a 100% Alamar blue solution. Following a 4 hour incubation period at 37 degrees C., samples were collected, plated in a fluorescence measurement system with 544 nm excitation and 590 nm emission. Control wells containing 10% Alamar blue solution were used to provide the background level measurements for oxidation of Alamar blue. Absorbance values were converted into cell numbers extrapolated from established standard curves. After 1 day the PFS modified sample according to the invention exhibited a remarkable acceleration of cell growth on its surface, 14,400 (±2,500) cells vs. 10,400 (±1,000) cells on the control sample. Samples taken after 4 days and 7 days also showed a remarkable acceleration of cell growth on the sample prepared according to the invention.
EXAMPLE 2
[0017] In one example, a liquid bath was made from a mixture of 69 grams of distilled water, 11 grams of HNO3, 20 grams of tricalcium phosphate, and 8 grams of phosphoric acid (H3PO4). A sample disc of Ti-6Al-4V was submerged in the bath, grounded to the PFS circuit, and supported by a non-conductive polymeric support. A stream of argon was bubbled into the bottom of the bath for agitation. A PFS electrode of the same alloy was connected to the PFS apparatus, and placed in operative proximity to the sample. A relatively low energy PFS process was then conducted for about 3 minutes during which current was passed through the electrode and into the sample. The sample was then removed from the bath, ultrasonically cleaned, and analyzed by Energy-Dispersive X-Ray Spectroscopy (EDX) for calcium and phosphorous content. The PFS-applied layer included 7.33 atomic % calcium and 5.22 atomic % phosphorous. The sample was then tested for tissue-growth enhancement by the same methods as in Example 1.
[0018] Following a 1, 4 and 7 day culture period, attachment and proliferation was measured as was done in Example 1. After 1 day the PFS modified sample according to this embodiment of the invention exhibited a similar acceleration of cell growth on its surface, 14,500 (±1,900) cells vs. 10,400 (±1.000) cells on the control sample. Samples taken after 4 days and 7 days also showed a dramatic acceleration of cell growth on the sample prepared according to this embodiment of the invention.
[0019] It is believed that further development will reveal processing solutions and methods that provide even greater increases in cell growth and attachment rates. Accordingly, while the invention has been illustrated by way of the foregoing examples, it is not intended to be limited by those examples to the compositions or processing conditions therein. Those of skill in the art will understand that the methods and implants illustrated by way of the foregoing examples could be modified in numerous ways without departing from the scope of the invention. | A biocompatible implant comprising a surface layer metallurgically bonded to a substrate and incorporating one or more tissue-growth enhancing materials such as calcium or phosphorus therein. The implant may formed by a submerged arc welding process, or other suitable methods. | 1 |
CROSS-REFERENCE TO OTHER APPLICATIONS
This Application is a divisional of patent application Ser. No. 09/952,653, filed on Sep. 13, 2001 now U.S. Pat. No. 6,730,860.
BACKGROUND OF THE INVENTION
1). Field of the Invention
This invention relates generally to an electronic assembly, typically of the kind having a package substrate secured to a printed circuit board utilizing solder bumps.
2). Discussion of Related Art
Integrated circuits are often manufactured in and on semiconductor wafers which are subsequently cut into individual semiconductor chips. A chip is then mounted to a package substrate and electrically connected thereto. The package substrate is then mounted to a printed circuit board.
Solder balls are usually located on the surface of the package substrate which is located against the printed circuit board. The combination is then heated and allowed to cool so that the solder balls form solder bumps which secure the package substrate structurally to the printed circuit board, in addition to electrically connecting the package substrate to the printed circuit board.
Electronic signals can be provided through the solder bumps between the printed circuit board and the integrated circuit. Other ones of the solder bumps provide power and ground to the integrated circuit. It may occur that high currents flow through some of the solder bumps, in particular those providing power or ground to the integrated circuit. These high currents may cause damage to the solder bumps. The solder bumps providing power, ground and signal communication are also usually equally spaced from one another thus taking up similar amounts of space.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is described by way of examples with reference to the accompanying drawings wherein:
FIG. 1 is a cross-sectional side view illustrating components of an electronic assembly according to an embodiment of the invention;
FIG. 2 is a view similar to FIG. 1 after the components are brought together, heated and allowed to cool;
FIG. 3 is a plan view illustrating the layout of solder bumps and vias of a printed circuit board of the electronic assembly;
FIG. 4 is a side view illustrating more components of the electronic assembly; and
FIG. 5 is a plan view of a printed circuit board according to another embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 of the accompanying drawings illustrates components of an electronic assembly 10 before being secured to one another. The electronic assembly 10 includes a package substrate subassembly 12 and a printed circuit board subassembly 14 .
The printed circuit board subassembly 14 includes a printed circuit board 16 , vias 18 , and contact pads 20 .
The printed circuit board 16 includes a number of layers including a power plane 22 , a ground plane 24 , and other layers 26 . The power plane 22 is separated from a ground plane 24 by one of the layers 26 . Another one of the layers 26 is located on top of the power plane 22 and a further one of the layers 26 is located on a lower surface of the ground plane 24 . The power and ground planes 20 and 24 are thus separated from one another by one of the layers 26 and spaced from upper and lower surfaces of the printed circuit board 16 by other ones of the layers 26 .
The vias 18 are located in the printed circuit board 16 and extend from the upper surface thereof to the lower surface thereof through the layers 22 , 24 , and 26 . The vias 18 include power vias 18 A, ground vias 18 B and signal vias 18 C. The power vias 18 A have lower ends connected to the power plane 22 . The ground vias 18 B have lower ends connected to the ground plane 24 . The signal vias 18 C are disconnected from the power and ground planes 22 and 24 .
The contact pads 20 include a power contact pad 20 A, a ground contact pad 20 B and signal contact pads 20 C. The power contact pad 20 A has a height measured in a direction from the bottom of the paper to the top of the paper, a width as measured into the paper, and a length as measured from the left to the right of the paper. The length is a multiple of the width. The power contact pad 20 A is located on all the power vias 18 A. Each one of the power vias 18 A is attached and connected to the power contact pad 20 A at a respective location along the length of the power contact pad 20 A. As such, the power vias 18 A connect the power contact pad 20 A in parallel to the power plane 22 . In another embodiment the vias may be located outside the contact pads in an arrangement commonly referred to as a “dogbone” configuration.
The ground contact pad 20 B, similarly, has a height, a width, and a length which is a multiple of the width. The ground contact pad 20 B is located on all the ground vias 18 B so that each ground via 18 B has a respective upper end connected to the ground contact pad 20 B at a respective location along its length.
Each signal contact pad 20 C is located on and connected to a respective one of the signal vias 16 C. Each signal contact pad 20 C is disconnected from every other contact pad 20 .
The package substrate subassembly 12 includes a package substrate 30 , vias 32 , bond pads 34 , and solder balls 36 . The package substrate 30 is also a multi-layer substrate having a ground plane and a power plane. The vias include power vias 32 A, ground vias 32 B, and signal vias 32 C. Each one of the power vias 32 A has an upper end connected to a ground plane in the package substrate 30 and each one of the ground vias 32 B has an upper end connected to a ground plane in the package substrate 30 .
The bond pads 34 include the power bond pads 34 A, ground bond pads 34 B, and signal bond pads 34 C, all located on a lower surface of the package substrate 30 . Each power bond pad 34 A is located on a respective lower end of a respective one of the power vias 32 A, each ground bond pad 34 B is located on a respective lower end of a respective ground via 32 B, and each signal bond pad 34 C is located on a respective lower end of a respective signal via 32 C.
The solder balls 36 include power solder balls 36 A, ground solder balls 36 B, and signal solder balls 36 C. Each power solder ball 36 A is located on a respective lower surface of a respective one of the power bond pads 34 A, each ground solder ball 36 B is located on a respective lower surface of a respective ground bond pad 34 B, and each signal solder ball 36 C is located on a respective lower surface of respective signal bond pads 34 C.
Each respective power via 32 A is aligned with one power bond pad 34 A, one power solder ball 36 A, and one power via 18 A. Center points of the power solder balls 36 A are spaced from one another by about 1 mm. A center point of the power solder ball 36 A on the right is spaced from a center point of the ground solder ball 36 B on the left by about 1.2 mm. Center points of the ground solder balls 36 B are spaced from one another by about 1 mm. A center point of the ground solder ball 36 B on the right is spaced from a center point of the signal solder ball 36 C on the left by about 1.2 mm. Center points of the signal solder balls 36 C are spaced from one another by about 1.2 mm. All the solder balls 36 A, B, and C have equal mass and size. Therefore, the combined mass of the power solder balls 36 A divided by the number of power vias 18 A equals the combined mass of the ground solder balls 36 B divided by the number of ground vias 18 B, and equals the combined mass of the signal solder balls 36 C divided by the number of signal vias 18 C.
The package substrate subassembly 12 is lowered onto the printed circuit board subassembly 14 so that lower surfaces of the solder balls 36 contact upper surfaces of the contact pads 18 A. All the power solder balls 36 A contact the power contact pad 20 A, all the ground solder balls 36 B contact the ground contact pad 20 B, and each signal solder ball 36 C contacts a respective one of the signal contact pads 20 C.
The combination of the package substrate assembly 12 and the printed circuit board subassembly 14 is then located in a reflow furnace. The solder balls 36 are heated to above their melting temperature so that they melt. The power solder balls 36 A combine when they melt due to their relative close spacing and the ground solder balls 36 B combine when they melt due to their relative close spacing. The power solder balls 36 A however do not combine with the ground solder balls 36 B. The signal solder balls 36 C remain disconnected from one another from the ground solder balls 36 B and from the power solder balls 36 A.
The combination of the package substrate subassembly 12 and the printed circuit board subassembly 14 is then removed from the reflow furnace and allowed to cool so that the material of the melted solder balls again solidifies. The solidified material of the power solder balls 36 A is represented in FIG. 2 of power solder bumps 40 B, the combination of the ground solder balls 36 B is represented as a ground solder bump 40 B, and the melted and reflowed signal solder balls 36 C is represented by signal solder bumps 40 C.
Each one of the power solder bumps 40 A has a height, a width, and a length with the width and length of the power solder bump 40 A correspond to the width and the length of the power contact pad 20 A. Similarly, the ground solder bump 40 B has a height, a width, and a length, the width and length corresponding to the width and length of the ground contact pad 20 B. As such, the power solder bump 40 B has a length which is a multiple of its width and the ground solder bump 40 B has a length which is a multiple of its width.
Upper ends of the power vias 18 A are connected through the power contact pads 20 A to respective points of the power solder bump 40 A along its length and upper ends of the ground vias 18 B are connected to the ground contact pad 20 B to the ground solder bump 40 B at respective locations along its length. The power solder bump 40 A is thus connected in parallel through the power vias 18 A to the power plane 22 and the ground solder bump is connected in parallel through the ground vias 18 B to the ground plane 24 .
An advantage of combining the power solder balls 36 A and combining the ground solder balls 36 B is that they can be located closer to one another. More space is so freed up for additional ones of the signal solder balls 36 C. Another advantage of combining the power solder balls 36 A and combining the ground solder balls 36 B is that potential high currents through individual ones of the balls 36 A or B can be distributed through the larger solder bumps 40 A or 40 B.
FIG. 3 is a more accurate representation of the relative positioning of the power and ground solder bumps 40 A and 40 B. The power and solder bumps 40 A and 40 B are represented by rectangles. The signal solder bumps 40 C are represented by larger circles. The power ground and signal vias 18 A, 18 B, and 18 C are represented by the smaller circles.
It can be seen that the power and ground solder bumps 40 A and 40 B are located in lines parallel to one another, directly adjacent one another with a respective ground solder bump 40 B located between two of the power solder bumps 40 A. A surface of one of the power solder bumps 40 A thus faces a respective surface of one of the ground solder bumps 40 B to form a plurality of capacitors. In the example illustrated, there are three power solder bumps 40 A and three ground solder bumps 40 D and five capacitors are created. The capacitors assist in reducing resistive and inductive time delay of power or ground signals. All the power and ground vias 18 A and 18 B are located over a rectangular area where there are none of the signal vias 18 C and all the signal vias are located around the rectangular area where all the power and ground vias 18 A and 18 B are located.
FIG. 4 illustrates more components of the electronic assembly. In addition to the package substrate 30 and the printed circuit board 16 , the electronic assembly 10 further includes a semiconductor chip 50 . The semiconductor chip 50 has an integrated circuit of electronic components therein The semiconductor chip 50 is mounted on the package substrate 30 and electrically connected thereto. Electronic signals can be provided to and from the integrated circuit in the semiconductor die 50 and the printed circuit board 16 through the solder bumps 40 and the package substrate 30 .
FIG. 5 illustrates another manner in which capacitors can be created with power and ground solder bumps. Similar reference numerals are used as in the embodiment of FIG. 3 . A power solder bump 140 has a plurality of limbs 140 A–E. The limbs 140 A–D all lead off the limb 140 E. A ground bump 150 is provided having limbs 150 A–E. The limbs 150 A–D lead off the limb 150 E. The limbs 150 A–D are located between the limbs 140 A–D so that the limbs 140 are alternated by the limbs 150 A–D. It has been found that a larger capacitor can be created over a given surface area by “fanning” the limbs into one another as illustrated in FIG. 5 .
While certain exemplary embodiments have been described and shown in the accompanying drawings, it is to be understood that such embodiments are merely illustrative and not restrictive of the current invention, and that this invention is not restricted to the specific constructions and arrangements shown and described since modifications may occur to those ordinarily skilled in the art. | Solder bumps are created on a substrate of an electronic assembly having lengths that are longer than the widths. The solder bumps are created by locating solder balls of power or ground connections close to one another so that, upon reflow, the solder balls combine. Signal solder balls however remain separated. Capacitors are created by locating power solder bumps adjacent ground solder bumps and extending parallel to one another. | 8 |
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional Patent Application Nos. 60/752,455 filed Dec. 21, 2005; 60/760,510 filed Jan. 20, 2006; 60/760,880 filed Jan. 20, 2006; 60/782,478 filed Mar. 15, 2006; 60/830,319 filed Jul. 12, 2006 and 60/830,326 filed Jul. 12, 2006; the contents of each being incorporated by reference herein.
FIELD OF THE INVENTION
[0002] This invention relates to the treatment of viral infections with topical formulations.
DISCUSSION OF THE RELATED ART
[0003] Viral infections are often highly infectious, rapidly mutating, and often debilitating. One type of viral disease is Herpes simplex—commonly referred to as cold sores or fever blisters. Herpes is a viral infection that causes lesions on the tissue of the infected such as blisters and sores. One feature of a virus is its potential for spread and reoccurrence. It is believed that when treated, the Herpes virus is never completely removed from the body, but resides and potentially spreads along the nervous system. For example a herpes virus outbreak that originally resides in the mouth can potentially spread along the nervous system to the eye or other parts of the face.
[0004] Herpes infections are very common. It is estimated that 90% of the population have been exposed to herpes—the most common outbreaks of herpes around the mucosal membranes of the mouth or genital region. Ocular herpes is relatively rare, but difficult to treat. When the eye is afflicted by herpes simplex, it usually affects only one eye and most often occurs on the cornea of the eye. This type of corneal infection is called Herpes Keratitis. The infection may be superficial, involving only the top layer of the cornea—referred to as the epithelium. Generally the lesions on the eye will heal without scarring. However, when the infection involves deeper layers of the cornea, it may lead to scars of the cornea, loss of vision, and sometimes even blindness. Less commonly, herpes simplex virus may also infect the inside of the eye (Herpes Uveitis) or the retina (Herpes Retinitis).
[0005] Current treatment for Herpes and other ocular viral disease may include administering systemic antiviral agents. One type of systemic antiviral agents have viral thymidine kinase activity. Viral thymidine kinase converts these drugs to a monophosphate form which disrupts replication of the virus. Examples of such include Valaciclovir (GlaxoSmithKline, Philadelphia, Pa.) disclosed in U.S. Pat. No. 4,957,924; Famciclovir (Novartis, East Hanover, N.J.) covered in U.S. Pat. No. 5,246,937; Tromantadine and Penciclovir (GlaxoSmithKline, Philadelphia, Pa.) disclosed in U.S. Pat. No. 5,075,445.
[0006] Another class of systemic treatment prevents the virus from attaching to cell membranes and thus, barring entry of the virus DNA to the host cell. This treatment method is effective for containing an outbreak of Herpes. Doccsanol sold under the trademark Abreva (GlaxoSmithKline, Philadelphia) is sold in a 10% topical cream form. U.S. Pat. No. 4,874,794 relates to doccsanol products.
[0007] Patients with topical virus infections may benefit from a topically administered antiviral ointment. Treatment of topical virus infections with a topical ointment compared to a systemic antiviral medicament will limit any toxicity of the medicine and other side effects because therapeutic levels of the antiviral agent is not required throughout the entire body. Ophthalmic ointments for treatment of ocular disease include but are not limited to Acyclovir ophthalmic ointment (GlaxoSmithKline, Philadelphia, Pa.) or Viroptic® 1.0% sterile ophthalmic solution of trifluridine (King Pharmaceuticals, Bristol, Tenn.).
[0008] For more developed infection, some ophthalmologists may also treat these patients by wiping away infected cells from the cornea with a dry, cotton-tipped applicator. Treatment may vary for deeper, more severe corneal infection and for herpetic inflammation within the eye. The antiviral eye drops presently available are less effective in treating these severe infections than early stage infections. Steroids, in the form of drops, may help decrease inflammation and corneal scarring. Despite the available treatments, some patients do not respond well or rapidly to treatment. These patients may have prolonged inflammation and ultimately permanent corneal scarring and may need corneal transplantation to restore their vision. Thus, better therapies for viral infection, including topical viral infection and particularly ocular viral infection, are required.
[0009] Biguanide antimicrobial agents have been used to preserve ophthalmic solutions and demonstrate relatively low toxicity in ocular tissues. Biguanide antimicrobial agents include polyhexamethylene biguanide, chlorhexidine and Alexidine.
[0010] To effectively preserve an ophthalmic composition, sufficient preservative is necessary to prevent growth of S. aureus, P. aeruginosa and E. coli bacteria and C. albicans and A. niger fungi over the shelf life of the product. Typically, a clinically effective formulation will contain an amount of a preservative required to accomplish the preservative effect without unnecessary excess. Between 0.5 ppm and 3.0 ppm of a biguanide has been used to preserve most ophthalmic solutions.
[0011] Biguanide antimicrobial agents have been used as disinfectant agents for contact lenses. To be considered a disinfectant, a solution needs sufficient antimicrobial agent to kill S. aureus, P. aeruginosa and S. marcescens bacteria and C. albicans and F. solani fungi over the shelf life of the product. Furthermore, the solution must show efficacy in disinfecting contact lenses using the disinfecting regimen that is recommended on the product. This regimen is arrived at through data which supports the disinfecting properties described above.
[0012] Disinfecting solutions containing antimicrobial agents include ReNu® Multiplus sold by Bausch & Lomb, Rochester, N.Y. ReNu® Multiplus is a multipurpose cleaning, conditioning and disinfecting solution for contact lenses that contains 1 ppm of polyhexamethylene biguanide. ReNu® with MoistureLoc is a multipurpose cleaning, conditioning and disinfecting solution for contact lenses that contains 4.5 ppm of Alexidine.
[0013] Disinfecting solutions such as the two mentioned above are ophthalmically safe solutions. They are safe to administer to the eye of a patient. Contact lenses that have been rinsed with these solutions are placed in the eye. However, these solutions are not approved for use as a medicament in the eye. There is no evidence to suggest that the level of antimicrobial agent in a multipurpose contact lens solution would be effective to treat ocular infection.
[0014] Several studies have been conducted on the effectiveness of polyhexamethylene biguanide and/or chlorhexidine for treatment of Acanthamoebal keratitis.
[0015] In Schuster, et al., “Opportunistic Amoebae: Challenges In Prophylaxis And Treatment,” Drug Resistance Updates: Reviews And Commentaries In Antimicrobial And Anticancer Chemotherapy , vol. 7(1) pp. 41-51 (February 2004), Acanthamoeba keratitis , a non-opportunistic infection of the cornea, was found to respond to treatment with chlorhexidine gluconate and polyhexamethylene biguanide, in combination with propamidine isothionate ( Brolene ), hexamidine ( Desomodine ), or neomycin.
[0016] In Rama et al., “Bilateral Acanthamoeba keratitis with late recurrence of the infection in a corneal graft: a case report,” European Journal of Ophthalmology , vol. 13 (3), pp. 311-4 (April 2003), recurrences of Acanthamoeba keratitis in both eyes were successfully treated with a combination of hexamidine and neomycin, and with polyhexamethylene biguanide, respectively.
[0017] Anita et al., “Role of 0.02% polyhexamethylene biguanide and 1% povidone iodine in experimental Aspergillus keratitis,” Cornea , Vol. 22 (2), pp. 138-41, (March 2003) showed that polyhexamethylene biguanide (0.02%) is a moderately effective drug for experimental Aspergillus keratitis.
[0018] Sharma et al., “Patient characteristics, diagnosis and treatment of non-contact lens related Acanthamoeba keratitis ,” British Journal of Ophthalmology, Vol. 84/10, pp. 1103-1108 (2000) illustrates the combination of polyhexamethylene biguanide and chlorhexidine.
[0019] Alexidine has been screened against Acanthamoeba keratitis in several studies. See Eye, vol. 17, pp. 893-905 (2003). J. Pharm. Pharmacol. (47, No. 12B, 1107, 1995) 1 Tab. 6 Ref. British Journal of Ophthalmology, (1996) Vol. 80, No. 9, pp. 849. Transactions of the Royal Society of Tropical Medicine and Hygiene (1995) 89, 245-247.
[0020] U.S. Pat. No. 5,942,218 teaches the use of an anti-infective material based upon polyhexamethylene biguanide as a component in an antiviral composition that can be used for wound treatment.
[0021] Consequently, there is a need for a topical antimicrobial composition that is effective treatment for viral infections. Additionally, there is a need for a topical ophthalmic antimicrobial composition that is effective for treatment of viral infections in the ocular region of the patient. The present invention addresses these and other needs.
SUMMARY OF INVENTION
[0022] The present invention, according to one embodiment, is a method of treating a viral infection comprising administering a topical composition to the skin or mucous membranes of a patient. The topical composition comprises a topically acceptable carrier and a biguanide containing antimicrobial agent.
[0023] The present invention, according to one embodiment, is a method of treating a viral infection comprising administering an ophthalmically acceptable composition to the ocular region of a patient, the ophthalmically acceptable composition comprising an ophthalmically acceptable carrier and a biguanide containing antimicrobial agent. The administration of the biguanide antimicrobial agent to the eye results in a reduction of the viral load in the eye. Typically, the administration of the biguanide antimicrobial agent results in a reduction of the viral load to the extent that the symptoms of the viral infection are reduced or, preferably eliminated. The topically or ophthalmically acceptable carrier is water containing carrier. In another embodiment, the topically or ophthalmically acceptable carrier is an oil, grease, wax or petrolatum based carrier.
[0024] The present invention, according to one embodiment, is administered to the ocular region of a patient. Typically, the ophthalmically acceptable composition can safely be administered to the eye of a patient. By safe, it is meant that the medicament is approved for use in the eye or is capable of being approved for use in the eye by the Food and Drug Administration. The medicament does not contain any ingredients that are toxic or harmful or cause an unacceptable degree of irritation to the eye of a patient according to FDA guidelines.
[0025] In another embodiment, the method includes treating a patient that is infected with a viral infection. In another embodiment, the method includes treating a patient that is infected with the Herpes virus. Typically, the patient is infected with Herpes Simplex-1. In another embodiment, the patient is infected with Herpes Simplex-2. In still another embodiment, the patient is infected with an adenovirus. In still another embodiment the adenovirus is Adenovirus Type-4 or Adenovirus Type-8. In one other embodiment, the virus is cytomegalovirus.
[0026] In another embodiment, there is a composition for treating infectious disease comprising water, and a biguanide containing antimicrobial agent in an amount effective to treat a viral infection.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0027] Alexidine is a biguanide antimicrobial agent that is defined by the formula 1,1′-hexamethylene-bis[5-(2-ethylhexyl)biguanide]. By biguanide antimicrobial agent it is meant an antimicrobial agent that has biguanide substituents and has antimicrobial properties in an ophthalmically safe amount. Suitable biguanide antimicrobial agents include but are not limited to 1,1′-hexamethylene-bis[5-(p-chlorophenyl)biguanide](Chlorhexidine) or water soluble salts thereof, 1,1′-hexamethylene-bis[5-(2-ethylhexyl)biguanide](Alexidine) or water-soluble salts thereof, and poly(hexamethylene biguanide) (PHMB).
[0028] In one embodiment, the amount of antimicrobial agent in the ophthalmic composition is a minimum of about 1 ppm and a maximum of about 10 wt. %. Typically, the amount of antimicrobial agent in the ophthalmic composition is a minimum of about 5 ppm, about 10 ppm, about 20 ppm, about 50 ppm, about 100 ppm or about 200 ppm. Typically, the amount of antimicrobial agent in the ophthlamic composition is a maximum of about 1 wt. %, 1000 ppm, about 500 ppm, about 300 ppm, about 100 ppm. In one embodiment, the amount of Alexidine is about 30 ppm. In another embodiment, the amount of Alexidine is about 300 ppm.
[0029] Due to the tendency of Alexidine or other biguanide antimicrobial agents to hydrolyze in an aqueous solution, it is desirable to include a stabilizer for formulations in which Alexidine is likely to hydrolyze. A stabilizer is a compound that prevents the chemical degradation of an active agent when the compound is in the presence of the stabilizer. Examples of stabilizers that are effective in an aqueous solution include but are not limited to hydroxyl alkyl phosphonate, Tetronics® 908, tyloxapol, cyclodextrin and derivatives of cyclodextrin, hyaluronic acid, sodium edetate, citric acid as well as ophthalmically acceptable antioxidants, complexing agents and chelating agents and salts thereof. In one embodiment, preferred stabilizers are hydroxyalkyl phosphonate, ethylenediamine-tetraacetic acid, Tetronics® 908, tyloxapol, cyclodextrin and derivatives of cyclodextrin, hyaluronic acid or EDTA.
[0030] In one embodiment, the stabilizer is present in an amount effective to stabilize the compound. An amount effective to stabilize a compound means that the stabilizer is present in an amount that prevents deterioration of at least 90% of the compound in a period of 24 months. In another embodiment, the preferred stabilizer is present in a minimum amount of about 0.001 wt. %, about 0.005 wt. %, about 0.01 wt. % and/or a maximum amount of about 5 wt. %, about 1 wt. %, about 0.5 wt. %, about 0.3 wt. %, about 0.1 wt. %, about 0.08 wt. %, about 0.05 wt. %, about 0.03 wt. %, about 0.01 wt. % based upon the total volume of the composition. In another embodiment, the stabilizer is a cyclodextrin or cyclodextrin derivative and is present in an amount that is a minimum of about 0.001 wt. %, about 0.005 wt. %, about 0.01 wt. % and/or a maximum of about 50 wt. %, about 40 wt. %, about 20 wt. % or about 10 wt. % cyclodextrin or cyclodextrin derivative based upon the total amount of the composition.
[0031] In another embodiment the effective shelf life of the antimicrobial agent is extended by a minimum of about 10 percent of the shelf life without the stabilizer. In another embodiment, the antimicrobial agent is extended by a minimum of about 20 percent, about 40 percent, about 80 percent, about 100 percent or about 200 percent.
[0000] Delivery Vehicle
[0032] In another embodiment, the composition of the present invention contains a delivery vehicle that increases the mean residence time of the active agent in the eye and/or enhances penetration in the eye. U.S. Pat. Nos. 6,884,788 or 6,261,547 or 5,800,807 or 5,618,800 or 5,496,811 disclose various ophthalmic delivery vehicles the teachings in these patents are incorporated by reference in their entirety.
[0033] Various anatomical barriers relating to the eye may underlie the poor intraocular penetrance of whole antibodies. In this regard, the cornea is the principal barrier to entry of foreign substances. It has two distinct penetration barriers, the corneal epithelium and the corneal stroma. Thus, it is desirable to use a penetration enhancer to improve the penetration of the active ingredients of the present invention.
[0034] The penetration enhancer generally acts to make the cell membranes less rigid and therefore more amenable to allowing passage of drug molecules between cells. The penetration enhancers preferably exert their penetration enhancing effect immediately upon application to the eye and maintain this effect for a period of approximately five to ten minutes. The penetration enhancers and any metabolites thereof must also be non-toxic to ophthalmic tissues. One or more penetration enhancers will generally be utilized in a minimum amount of about 0.01 weight percent and/or a maximum of about 10 wt. %.
[0035] The preferred penetration enhancers are saccharide surfactants, such as dodecylmaltoside (“DDM”), and monoacyl phosphoglycerides, such as lysophosphatidylcholine. The saccharide surfactants and monoacyl phosphoglycerides, which may be utilized, as penetration enhancers in the present invention are known compounds. The use of such compounds to enhance the penetration of ophthalmic drugs is described in U.S. Pat. No. 5,221,696 the entire contents of which are incorporated by reference into the present specification.
[0036] The viscosifiers are optionally used in the present invention to increase the mean residence time of the active ingredient in the eye. With the aid of a viscosifier, liquid drops can be used having a viscosity that is a minimum of about 2 cps and a maximum of about 100 cps. Viscosifiers can be used to formulate liquid gels that have a viscosity that is a minimum of about 100 cps and a maximum of about 1000 cps. Ophthalmic gels will generally have a viscosity in excess of about 1,000 cps. Regardless, the viscosifier is utilized to ensure an adequate mean residence time in the eye. Any synthetic or natural polymer, which is capable of forming a viscous or a solid insert, may be utilized. In addition to having the physical properties required to form a viscous gel or solid insert, the polymers must also be compatible with tissues of the eye. The polymers must also be chemically and physically compatible with the above-described active agent and other components of the compositions.
[0037] Polymers, which satisfy the foregoing criteria, are referred to herein as “ophthalmically acceptable viscous polymers.” Examples of suitable polymers include: natural polysaccharides and gums, such as alginate, carrageenan, guar, karaya, locust bean, tragacanth agarose and xanthan; modified naturally occurring polymers such as carboxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, methylcellulose, hydroxypropylmethylguar and carboxymethyguar, synthetic polymers, such as carboxy vinyl polymers, polyvinyl alcohol and polyvinyl pyrrolidone.
[0038] In addition, proteins and synthetic polypeptides that form viscous gels and are ophthalmically acceptable can be used to provide better bioavailability. Typically, proteins that can be used include: gelatin, collagen, albumin, whey protein and casein.
[0039] Polymers which have high molecular weights and, most importantly, physical properties that mimic the physical properties of the mucous secretions found in the eye are referred to herein as being “mucomimetic.” A preferred class of mucomimetic polymers are carboxy vinyl polymers having molecular weights in the range of from about 50,000 to about 6,000,000. The polymers have carboxylic acid functional groups and preferably contain between 2 and 7 carbon atoms per functional group. The gels that form during preparation of the ophthalmic polymer dispersion have a viscosity between about 1,000 to about 300,000 centipoise (cps). Suitable carboxy vinyl polymers include those called carbomers, e.g., Carbopol® P (B.F. Goodrich Co., Cleveland, Ohio). Specifically preferred are carbomer 934, 940, 970, 974 and 980. Such polymers will typically be employed in an amount between about 0.05 and about 8.0 wt %, depending on the desired viscosity of the composition.
[0040] Aqueous compositions of the invention have an ophthalmically compatible pH, which generally will range between about 6 to about 8, and more preferably between 6.5 to 7.8, and most preferably about 7 to 7.5. One or more conventional buffers may be employed to obtain the desired pH value. Suitable buffers include for example but are not limited to borate buffers based on boric acid and/or sodium borate, phosphate buffers based on Na 2 HPO 4 , NaH 2 PO 4 and/or KH 2 PO 4 , citrate buffers based on sodium or potassium citrate and/or citric acid, succinate buffers, sodium bicarbonate, aminoalcohol buffers, Good buffers and combinations thereof. Generally, buffers will be used in amounts ranging from about 0.05 to about 2.5 weight percent, and preferably, from about 0.1 to about 1.5 weight percent.
[0041] Compositions of the present invention likewise include one or more tonicity agents to approximate the osmotic pressure of normal lachrymal fluids, which is equivalent to a 0.9 percent solution of sodium chloride or 2.5 percent glycerin solution. Examples of suitable tonicity agents include but are not limited to sodium and potassium chloride, dextrose, mannose, glycerin, calcium and magnesium chloride. These agents are typically used individually in amounts that are a minimum of about 0.01 wt. % or about 0.2 wt. % and/or a maximum of about 2.5 wt. % or 1.5 wt. %. Preferably, the tonicity agent is employed in an amount to provide a final osmotic value that is a minimum of about 200 mOsm/kg, about 220 mOsm/kg and/or a maximum of about 450 mOsm/kg, about 350 mOsm/kg or about 320 mOsm/kg.
[0042] Aqueous compositions may likewise include a humectant to provide moisture to the eye. A first class of humectants is polymer humectants. Examples of suitable humectants include for example but are not limited to poly(vinyl alcohol) (PVA), poly(N-vinylpyrrolidone) (PVP), cellulose derivatives and poly(ethylene glycol). As disclosed in U.S. Pat. No. 6,274,133, cationic cellulosic polymers include for example but are not limited to water soluble polymers commercially available under the CTFA (Cosmetic, Toiletry, and Fragrance Association) designation Polyquaternium-10, including the cationic cellulosic polymers available under the trade name UCARE® Polymers from Amerchol Corp., Edison, N.J., such as for example but not limited to Polymer JR™. Generally, these cationic cellulose polymers contain quaternized N,N-dimethylamino groups along the cellulosic polymer chain.
[0043] Another suitable class of humectants is non-polymeric humectants. Examples may include glycerin, propylene glycol, and other non-polymeric diols and glycols. The specific quantities of humectants used in the invention will vary depending upon the application. However, the humectants will typically be included in an amount from about 0.01 to about 5 weight percent, preferably from about 0.1 to about 2 weight percent.
[0044] It will be understood that some constituents possess more than one functional attribute. For example, cellulose derivatives are suitable polymeric humectants, but are also referred to as “viscosity increasing agents” to increase viscosity of the composition if desired. Glycerin is a suitable non-polymeric humectant but is also may contribute to adjusting tonicity.
[0045] Compositions of the present invention may optionally include one or more sequestering agents. Suitable sequestering agents include for example but are not limited to ethylenediaminetetraacetic acid (EDTA) and its salts. Sequestering agents are preferably present in a minimum of about 0.01 wt. % and/or a maximum of about 0.2 wt. %.
[0046] It will be understood that the present invention is typically applied by administering a composition to the eye of a patient in the form of eye drops, liquid gels or viscous gels. In one embodiment, one to four drops are applied to each eye. Preferably two drops are applied to each eye. In one embodiment, the drops are placed directly on the eye. In another embodiment, the drops are placed in the conjuntival sac beneath the eye.
[0047] Typically, the drops are administered a minimum of once daily, two times daily or three times daily.
EXAMPLES
Example 1
HSV-1 Viral Suspension Assay
[0048] The Viral Suspension Assay was used to evaluate the antiviral properties of Alexidine against Herpes simplex virus type 1 when exposed in suspension for 1, 2, 5, and 10 minutes. The presence of virus (infectivity) was determined by monitoring the virus specific cytopathic effect (CPE) on an appropriate indicator cell line, rabbit kidney. Results are reported as Percent (%) Reduction in virus titer as compared to the corresponding virus control titer (Table 1). The titer of the virus controls were 7.5 log 10 following the one minute exposure time; 7.0 log 10 following the two minute exposure time; and 7.75 log 10 following both the five and ten minute exposure times. The results are listed in Table 1 and show that Alexidine at both 30 ppm and 99 ppm are effective agents against herpes simplex type-1 virus (HSV-1).
TABLE 1 Viral Suspension Assay Percent Reduction of Herpes simplex virus type 1 after 1, 2, 5 and 10 Minute Exposure to Alexidine Alexidine Test Concentration 1 minute 2 minutes 5 minutes 10 minutes 30 ppm 99.99% 99.99% 99.9994% ≧99.99994% 99 ppm 99.999% 99.994% 99.9999% ≧99.99994%
Example 2
Adenovirus and Cytomegalovirus Testing
[0049] The Viral Suspension Assay was used to evaluate the antiviral properties of Alexidine against Adenovirus Type-4, Adenovirus Type-8 and Adenovirus Type-19 and Cytomegalovirus when exposed in suspension for 1, 2, 5, and 10 minutes. The presence of virus (infectivity) was determined by monitoring the virus specific cytopathic effect (CPE) on an appropriate indicator cell line, rabbit kidney. Results are reported as Percent (%) Reduction in virus titer as compared to the corresponding virus control titer (Table 1). The titer of the virus controls were 7.5 log 10 following the one minute exposure time; 7.0 log 10 following the two minute exposure time; and 7.75 log 10 following both the five and ten minute exposure times. The results are listed in Table 1 and show that Alexidine at both 30 ppm and 99 ppm are somewhat effective against viral strains of Adenovirus Type-4, Adenovirus Type-8, and Cytomegalovirus. However, Alexidine did not appear to be effective against the particular strain of Adenovirus Type-19 that was tested. Alexidine is a potent antimicrobial agent against Herpes Simplex-1 and has some effectiveness against certain strains of other viruses that cause ocular infection.
TABLE 2 Viral Suspension Assay Percent Reduction of Adenovirus Type-4, Adenovirus Type-8 and Adenovirus Type-19 and Cytomegalovirus after 1, 2, 5 and 10 Minute Exposure to Alexidine Alexidine Percent Reduction (%) Test 1 2 5 10 Virus Concentration minute minutes minutes minutes Adenovirus 30 ppm 43.8 — 82.2 68.4 type 4 99 ppm 68.4 — 43.8 68.4 Adenovirus 30 ppm 96.8 94.4 82.2 90.0 type 8 99 ppm 82.2 82.2 90.0 90.0 Adenovirus 30 ppm No reduction type 19 99 ppm Cytomegalovirus 30 ppm 43.8 68.4 — 43.8 99 ppm 98.2 99.0 99.8 99.98 | An ophthalmically acceptable composition comprising to the ocular region of a patient, the ophthalmically acceptable composition comprising water, a biguanide containing antimicrobial in an amount effective to treat viral infection. The invention further comprises administering the ophthalmically acceptable composition to the eye of a patient in need of treatment. | 0 |
BACKGROUND OF THE INVENTION
The invention relates to a fire control system for a vehicle or vessel, which fire control system is provided with:
a turret and gun;
a target tracking unit;
a data processor connected to the target tracking unit for determining, in a first coordinate system coupled to the target tracking unit, angular (error) data about the position of the target being tracked;
a servo control unit connected to the data processor for aligning the target tracking unit with the target position by means of the angular error data supplied; and
a fire control computer for determining, from a series of successive positions of the target tracking unit and target range values, associated target positions in a second, fixed horizontal coordinate system, and for generating, from said target positions, gun aiming data for transmission to the turret and gun.
Such a fire control system for a vehicle or vessel is widely known.
With a combat vehicle fitted with a spring-suspended chassis on pneumatic tires and with the abovementioned fire control system, it is customary to stop the vehicle when entering the aiming phase of the gun and to give the vehicle a stable position by means of collapsible levelling jacks. This ensures that with a burst of fire the position of the combat vehicle will not be subject to change through the gun recoil. The use of these levelling jacks for such a vehicle could of course be dispensed with if only one single round need be fired. Furthermore, a heavy combat vehicle, such as a tank, need not be fitted with levelling jacks since, due to the large mass of the vehicle, the recoil of the gun when fired has no appreciable effect on the position of this vehicle. The adjustment of levelling jacks for a combat vehicle fitted with a spring-suspended chassis on pneumatic tires and with the above-mentioned fire control system is however time-consuming, and hence a disadvantage of such a combat vehicle.
SUMMARY OF THE INVENTION
The present invention has for its object to obviate the disadvantage with the use of the above fire control system for a vehicle fitted with a spring-suspended chassis on pneumatic tires or for a rolling vessel.
According to the invention, in a fire control system of the type set forth in the opening paragraph the fire control computer comprises a (first) coordinate conversion unit for determining the elements of the transformation matrix (H) associated with the transformation from the first coordinate system to the second coordinate system, using supplied data concerning the relative angular positions measured at the axes of rotation between the target tracking unit, the turret, and the vehicle or vessel, and using data supplied by reference orientation means and concerning the angular positions with respect to the tilt of the vehicle or vessel in the second coordinate system, and for converting the angular error data obtained from the data processor in the first coordinate system into target positions in the second coordinate system, using the elements of said transformation matrix. The fire control computer further comprises a (second) coordinate conversion unit for transforming, on the basis of the data supplied by said reference orientation means, the gun aiming data determined in the second coordinate system to a third coordinate system coupled to the vehicle or vessel.
A preferred embodiment of a fire control system, according to the invention, for a vehicle fitted with a spring-suspended chassis or a vessel subject to roll, pitch and yaw motions is obtained by transforming the gun aiming data determined in the second coordinate system first to the first coordinate system, using matrix H*, where H*=H -1 , being the inverse of matrix H, and by transforming the gun aiming data determined in the first coordinate system to the third coordinate system on the basis of the data concerning the angular positions at the axes of rotation between the target tracking unit, the turret, and the vehicle or vessel.
BRIEF DESCRIPTION OF THE DRAWING
The invention will now be described with reference to the accompanying figures, of which:
FIG. 1 is a schematic representation of a vehicle fitted with a fire control system;
FIG. 2 is a block diagram of a fire control system, according to the invention, for a vehicle or vessel; and
FIGS. 3 and 4 are orthogonal coordinate systems containing transformations to be effected.
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 shows a three-axle combat vehicle 1, provided with a turret 2 and gun 3. Vehicle 1 is fitted with a spring-suspended chassis on pneumatic tires. The turret 2 is rotatable about an axis 4, which is perpendicular to the roof 5 of vehicle 1. The gun 3 is movable in elevation about an axis 6 in the turret 2; axis 6 is oriented parallel to the roof 5. Mounted on the turret 2 is a target tracking unit 7 for tracking a target in range and in angles. The target tracking unit 7 may consist of a radar tracking apparatus, a laser range detector, an infrared tracking unit, a TV tracking unit or optical detection means (periscope, binocular), as well as combinations thereof. The target tracking unit 7 is biaxially connected with the turret 2, one axis 8 being oriented parallel to or coaxially with axis 4 on the turret 2 and the other axis 9 parallel to the roof 5. The relative motion of the turret 2 with respect to the vehicle 1 (about axis 4), the gun 3 with respect to the turret 2 (about axis 6), and the target tracking unit 7 with respect to the turret 2 (about axes 8 and 9), is achieved by servo control units 10, 11, 12 and 13, respectively, shown schematically in FIG. 1. The angular rotations of the turret 2 with respect to the vehicle 1 (about axis 4), the gun 3 with respect to the turret 2 (about axis 6), and the target tracking unit 7 with respect to the turret 2 (about axes 8 and 9) are measured by angle data transmitters 14, 15, 16 and 17, respectively, shown schematically in FIG. 1, which transmitters may be synchros, digital angle data transmitters, etc.
The vehicle 1 is further provided with reference orientation means for obtaining time-reliable data about the orientation of the vehicle with respect to a fixed horizontal (second) coordinate system; the reference orientation means may consist of a three-axis, vertical gyroscope 18 and/or rate gyroscopes 19 and 20, shown schematically. The rate gyroscopes 19 and 20 are mounted on the axes 8 and 9 and furnish data about the angular velocities of the rate gyroscopes relative to the fixed horizontal plane. After fractional integration and after correction for the initial values of the tilt of target tracking unit 7, as determined by gyroscope 18, the results obtained from the measurements of these angular velocities yield the instantaneous tilt angles of a plane defined by axis 9 and the line of sight of the target tracking unit 7, which tilt angles are relative to the fixed horizontal plane. It should be noted that axis 9 may be tilted at an angle to the base plane of the second coordinate system through the combat vehicle being located on hilly ground and/or through the recoil of the gun 3. The required initial values of the tilt may be furnished separately, for instance, by gyroscope 18. With such a (joint) operation of gyroscope 18 and rate gyroscopes 19 and 20 it suffices to use a coarse, single-axis gyroscope 18 and accurate rate gyroscopes 19 and 20. In the absence of rate gyroscopes 19 and 20, the gyroscope 18 should be multi-axial and should provide accurate measuring results.
FIG. 2 is a block diagram of a fire control system for the combat vehicle 1 of FIG. 1. The fire control system contains a data processor 21, which is fed with angle and range data from the target tracking unit 7. During target tracking the data processor 21 furnishes data about the angular deviation between the line of sight of the target tracking unit 7 and the target line of sight, and hence target positional values in a first coordinate system coupled to the target tracking unit 7 and oriented perpendicularly to the line of sight of this unit. In a fire control computer 22 the target positional values are converted to a second, fixed horizontal coordinate system to generate the target track by means of an aiming-point generator 23 and, hence, to calculate aiming values for the gun 3. The fire control computer 22 comprises a first coordinate conversion unit 24, containing means 25 for establishing the elements of the matrix (H) associated with the transformation of the first coordinate system coupled to the target tracking unit 7 to the second coordinate system. Means 25 is supplied with the data from the angle data transmitters 14-17 and the reference orientation means 18, 19 and 20. For the transformation (H) of a target position (z) from the target tracking unit 7 to the second horizontal coordinate system the first coordinate conversion unit 24 further contains another transformation unit 26 to provide H(z) as the target position in the second coordinate system. On the basis of a series of target positions thus obtained (in the second coordinate system) and an associated series of target range values obtained from data processor 21, the aiming-point generator 23 is capable of generating the target track and calculating aiming values with the aid of additionally supplied data about ballistic corrections to be made and the data from rate gyroscope 18 about the gravitational direction.
Since the gun 3 is always aimed relative to the vehicle 1, the aiming data must be transformed from the second coordinate system to a third coordinate system coupled to the vehicle 1. To carry out such a transformation V, the fire control computer 22 comprises a transformation unit 27, using a matrix whose elements are calculable with the aid of the data supplied by the reference orientation means 18, 19 and 20. A preferred embodiment of such a transformation unit 27 comprises: a unit 28 for transforming the aiming values from the second coordinate system to the first coordinate system coupled to the target tracking unit 7; a unit 29 for transforming the aiming values obtained from unit 28 in the first coordinate system to a coordinate system coupled to the turret 2; and a unit 30 for transforming the aiming values obtained from unit 29 to the third coordinate system coupled to the vehicle 1. The transformation in unit 28 is realised by elements of a matrix H*, where H*=H -1 , being the inverse of matrix H, while the transformation in units 29 and 30 consists of correcting the supplied aiming values obtained from the angular values of the angle data transmitters. The aiming values thus obtained are supplied to servo control units 10 and 11.
Servo control unit 13 coupled to axis 9 is controlled with the angular error data of data processor 21 measured along the coordinate axis of the first coordinate system which is perpendicular to axis 9. Rotation of turret 2 about axis 4 also changes the position of the spatial aiming point of target tracking unit 7; to obtain a true tracking motion of tracking unit 7, any interferences in the tracking motion of target tracking unit 7, due to rotation of turret 2, must be compensated. To this effect the servo control unit 12 acting about axis 8 receives the angular data from angle data transmitter 14, in addition to the angular error data supplied by data processor 21 and measured along the coordinate axis of the first coordinate system which is parallel to axis 9. If target tracking unit 7 were rotatably mounted on the gun 3, the servo control unit 13 would have to be supplied with the angular data from angle data transmitter 15, as well as with the angular error data from data processor 21.
The above-described fire control system is also applicable to rolling vessels, where the transformation of the target coordinates to the second coordinate system according to matrix H compensates for the roll, pitch and yaw motions of the vessel.
If the target tracking unit 7 is directly and rotatably mounted on the roof 5 of the vehicle, the units 29 and 30 are of a combined design.
Reaction forces exerted on the vehicle or vessel due to bursts of fire are measured in the target tracking unit 7 and in the reference orientation means 18 and/or 19, 20. Under these conditions, the angular data from data processor 21, as well as the elements of matrix H constituted by means 25, are subject to change, such that the result of transformation unit 26, i.e. H(z), represents the true target motion, undisturbed by the gun recoil. Also the rocking motions of the combat vehicle driving on hilly ground or the rolling motions of a ship have no influence on the target position H(z) produced. The target data transformation in the first coordinate system, coupled to target tracking unit 7, on the basis of the position of target tracking unit 7 in the fixed horizontal system, thus provides true target data in the horizontal coordinate system, which does not show any dependency on the target tracking unit 7 subjected to motion.
A condition for proper operation of the above fire control system is however that the processing of the target motion, varying as a consequence of the vehicle or vessel motions, as performed by the target tracking unit 7 and data processor 21, be in synchronism with the processing of the associated data from the reference orientation means (18 and/or 19, 20) and angle data transmitters 14-17, as performed by means 25. This processing rate should be sufficiently large to permit any corrections to be made to the measured target positions during a burst of fire on account of the gun recoil, in order to position the gun 3 in accordance with the aiming values (still subject to variations at that time) during this burst.
The form of matrix H may be obtained as follows: FIG. 3 shows the orthogonal first coordinate system coupled to the target tracking unit 7, to be rotated through an angle φ about an axis e to obtain the fixed, horizontal, second coordinate system. In the X, Y and Z directions the reference orientation means measure the results E, Q and B, where the rotation vector e T is defined. The direction cosines of rotation vector e T are: ##EQU1## Instead of rotating the coordinate axes X, Y and Z, it is possible to rotate a random vector r through an angle φ about the axis e. To this effect, allow a plane to cut vector r at point P and to pass axis e at right angles. In this plane two mutually perpendicular unit vectors a and b are chosen, vector a lying along the line 0'P, where 0' is the point of intersection of this plane with vector e. The two unit vectors a and b may be expressed by:
a=r-(e,r)e
and
b=[e×r].
The vector q obtained after rotation through angle φ is given by: ##EQU2## where: ##EQU3## The matrix H to transform r to q will be: ##EQU4## Since the rotation angle φ may usually be considered small, cosφ and sinφ may be approximated by 1-φ 2 and φ, respectively. After substitution of l, m and n for their equivalent expressions, the matrix H obtained is: | In a fire control system for a vehicle or vessel a data processor (21) connected to the target tracking unit (7) determines, in a first coordinate system coupled to said unit (7), angular error data about a target position for aligning the tracking unit (7) with the target position.
A fire control computer (22) is incorporated for:
a. determining matrix (H) elements concerning the transformation from the first coordinate system to a second fixed horizontal coordinate system, using data about relative angular positions between the tracking unit (7), the vehicle or vessel and a turret mounted thereon, and using data from reference orientation means (18, 19, 20) about the angular positions in said second coordinate system;
b. converting the angular error data into target positions in said second coordinate system;
c. changing said target positions to gun aiming data; and
d. transforming the latter data to a third coordinate system coupled to the vehicle or vessel. | 5 |
CROSS REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of U.S. Provisional Patent Application having serial number 60/075,631, filed on Feb. 21, 1998, entitled “Automated Test Vector Generation and Verification.” This application is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to integrated circuits, and more particularly to methods for automated test vector generation and verification.
2. Description of the Related Art
Testing integrated circuits that are ultimately fabricated onto silicon chips has over the years increased in complexity as the demand has grown, and continues to grow for faster and more densely integrated silicon chips. In an effort to automate the design and fabrication of circuit designs, designers commonly implement hardware descriptive languages (HDL), such as Verilog, to functionally define the characteristics of the design. The Verilog code is then capable of being synthesized in order to generate what is known as a “netlist.” A netlist is essentially a list of “nets,” which specify components (know as “cells”) and their interconnections which are designed to meet a circuit design's performance constraints. The “netlist” therefore defines the connectivity between pins of the various cells of an integrated circuit design. To fabricate the silicon version of the design, well known “place and route” software tools that make use of the netlist data to design the physical layout, including transistor locations and interconnect wiring.
When testing of the digital model, various test vectors are designed in order to test the integrated circuit's response under custom stimulation. For example, if the integrated circuit is a SCSI host adapter chip, the test vectors will simulate the response of the SCSI host adapter chip as if it were actually connected to a host computer and some kind of peripheral device were connected to the chip. In a typical test environment, a test bench that includes a multitude of different tests are used to complete a thorough testing of the chip. However, running the test vectors of the test bench will only ensure that the computer simulated model of the chip design will work, and not the actual physical chip in its silicon form.
To test a silicon chip 12 after it has been packaged, it is inserted into a loadboard 14 that is part of a test station 10 , which is shown in FIG. 1 A. Although the model of the chip design was already tested using the test vectors of the test bench, these test vectors are not capable of being implemented in the test station 10 without substantial modifications, to take into account the differences between a “model” and a “physical” design. In the prior art, the conversion of a test model test vector into test vectors that can actually be run on the test station 10 required a very laborious process that was unfortunately prone to computer computational errors as well as human errors. Of course, if any type of error is introduced during the generation of the test vectors that will ultimately be run on the silicon chip 12 , the testing results generated by the test station 10 would indicate that errors exist with the part, when in fact, the part functions properly. This predicament is of course quite costly, because fabrication plants would necessarily have to postpone release of a chip until the test station indicated that the part worked as intended.
As mentioned above, the prior art test vector generation methodology was quite laborious, which in many circumstances was exacerbated by the complexity of the tests and size of the chip being tested. The methodology required having a test engineer manually type up the commands necessary to subsequently generate a “print-on-change” file once executed using Verilog. Defining the commands for generating the print-on-change file includes, for example, typing in the output enable information for each pin, defining pin wires, setting up special over-rides for power-on reset pins, etc. At this point, the print-on-change file would then be generated using a Verilog program, which in turn uses the commands generated by the test engineer.
In addition to manually producing these commands, a separate parameter file having timing information is separately produced in a manual typing-in fashion by the engineer. The generated print-on-change file and the parameter file are then processed by a program that is configured to produce a test file, which is commonly referred to as an AVF file. However, the production of the AVF is very computationally intensive because the generated print-on-change file can be quite large. The size of the print-on-change file grows to very large sizes because every time a pin in the design changes states, a line of the print-on-change file is dumped. Thus, the more pins in the design, more CPU time is required to convert the print-on-change file into a usable AVF file. In some cases where the test is very large or complex, the host computer processing the print-on-change file is known to crash or in some cases lock-up due to the shear voluminous amount of data.
Unfortunately, as mentioned above, the generated AVF file may have defects, such as timing errors, which may translate into errors being reported by the test station 10 . The problem here is that the test station 10 will stimulate the part differently than the stimulation designed for the digital version. This problem therefore presents a very time consuming test and re-test of the part by the test station 10 . When re-testing is performed, many modifications to the parameter file, containing timing information, are performed in an effort to debug errors with the AVF file. Although some parts are in fact defective in some way, the test engineer is still commonly required to re-run the tests to determine whether the errors are due to a defective AVF file or the physical device.
In view of the foregoing, there is a need for a method that reduces test vector generation cycle time, as well as increases the accuracy of test vector generation and simulation processes. Another need exists for a new method for automating the generation of the initial AVF file, which reduces computation time and reduces test engineer manual interaction that is susceptible to the introduction of errors. There is also a need for a method for automatically verifying whether the generated AVF file is free of defects, which will enable a substantial reduction in test cycle time.
SUMMARY OF THE INVENTION
Broadly speaking, the present invention fills these needs by providing a method to reduce test vector generation cycle time, as well as increase the accuracy of test vector generation and simulation processes. It should be appreciated that the present invention can be implemented in numerous ways, including as a process, an apparatus, a system, a device, a method, or a computer readable medium. Several inventive embodiments of the present invention are described below.
In one embodiment, a method for generating AVF test file data for use in testing a simulation of an integrated circuit design and subsequently testing a physical silicon version of the integrated circuit design is disclosed. The method includes providing a map file that contains a plurality of identifying statements for each multiple port I/O cell in the integrated circuit design. Then, generate a verilog executable file for the integrated circuit design. The verilog executable file is configured to contain data associated with the map file, output enable data derived from a netlist, and AVF data conversion information. The method further comprises executing the verilog executable file along with a test bench that includes the netlist of the integrated circuit design, a set of test files, and models. The execution is configured to produce the AVF test file data and a DUT timing file data.
In another embodiment, an automated test vector verification method is disclosed. The method includes receiving an AVF test file of an integrated circuit design and receiving a DUT test file of the integrated circuit design. The method then executes using the AVF test file and the DUT test file to produce an input vector (.invec), an environment file (.env), and an expected output vector (.outvec). Then, the method provides the input vector to a standalone chip on a model test station. Once provided to the standalone chip on a model test station, the method will execute the environment file that causes the input vector to be processed through the standalone chip on the model test station. The executing is configured to produce an output vector from the model test station. Then, the method compares the output vector from the model test station with the expected output vector. Finally, the method will determine whether the comparing produces a match that indicates that the AVF test file data is free of errors. When the AVF test file data is not free of errors, the method further comprises the option of processing through a verification loop.
In this embodiment, the verification loop includes: (a) modifying a test file data that is used to generate the AVF test file data and the DUT test file data; (b) generating a new AVF test file data and a new DUT test file data; (c) running the automated test vector verification method using the new AVF test file data and the new DUT test file data; and (d) determining whether the comparing produces a match that indicates that the AVF test file data is free of errors.
In yet another embodiment, a method for generating AVF test file data for use in testing a simulation of an integrated circuit design and subsequently testing a physical silicon version of the integrated circuit design is disclosed. The method includes providing a map file that contains a plurality of identifying statements for each multiple port I/ 0 cell in the integrated circuit design. Then generating a verilog executable file for the integrated circuit design. The generation of the verilog executable file includes: (a) reading the map file; (b) reading a netlist of the integrated circuit design; (c) generating a list of pins for the integrated circuit design; (d) defining output enable data for each pin of the integrated circuit design; (e) defining an AVF data conversion function having AVF data conversion information; (f) reading the generated list of pins; (g) generating code that produces timing for a DUT file for each pin in the generated list of pins; (h) generating a display statement; and (i) generating DUT creation code. The method then includes executing the verilog executable file along with a test bench that includes the netlist of the integrated circuit design, a set of test files, and models. The execution is configured to produce the AVF test file data and a DUT timing file data.
In still another embodiment, another automated test vector verification method is disclosed. The method includes receiving an AVF test file and a DUT test file of an integrated circuit design. Executing the AVF test file and the DUT test file to produce an input vector, an environment file, and an expected output vector. Providing the input vector to a standalone chip on a model test station. Executing the environment file that causes the input vector to be processed through the standalone chip on the model test station. The executing is configured to produce an output vector from the model test station. The method then proceeds to comparing the output vector from the model test station with the expected output vector, and determining whether the comparing produces a match that indicates that the AVF test file data is free of errors. The method then includes running the automated test vector verification method for a plurality of test files of the AVF test file data, and generating a test result log.
In another embodiment, a method for generating a map file for I/O cells of an integrated circuit design is disclosed. The map file, in this embodiment, will be generated for both single port and multi port cells. The method includes: (a) generating an output enable equation for a current cell type; (b) determining a port name for a current signal name; (c) inputting the determined port name for the current signal name into the map file; and (d) repeating (a)-(c) once for a single port cell and multiple times for a multi port cell.
These methods of the present invention therefore remove the uncertainty involved with standard vector conversion, by providing an automated way of generating vectors, as well as providing a verification methodology. By automating the vector generation and conversion process, at-speed testing can now accurately be performed. The process of the present invention also automatically senses input timings and creates a timing definition (DUT) file that can be used in the conversion/verification process. This therefore creates a virtually “hands-off” test vector generation/verification methodology.
Other aspects and advantages of the invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will be readily understood by the following detailed description in conjunction with the accompanying drawings, wherein like reference numerals designate like structural elements.
FIG. 1 illustrates a test station that is typically used in testing physical silicon integrated circuit devices.
FIG. 2 illustrates a flowchart that details the operations performed in generating an AVF file, a DUT file, and a log file in accordance with one embodiment of the present invention.
FIG. 3 illustrates a flowchart which illustrates the execution of the AVF generator (avfgen) that is configured to produce an avf.v file in accordance with one embodiment of the present invention.
FIG. 4A illustrate example AVF generator commands in accordance with one embodiment of the present invention.
FIGS. 4B and 4C illustrate a more simplified example of a chip design and an associated command line entry in accordance with one embodiment of the present invention.
FIG. 5A illustrates a flowchart defining the method operations performed in generating a map file for a particular chip design in accordance with one embodiment of the present invention.
FIGS. 5B and 5C illustrate an example of a multiple I/O port cell and a map file entry in accordance with one embodiment of the present invention.
FIG. 5D illustrates the method of generating a map file for all I/O cells, including single and multi port cells, in accordance with one embodiment of the present invention.
FIG. 6A illustrates an example of the method operations performed in generating a list of pins for the chip design in accordance with one embodiment of the present invention.
FIGS. 6B through 6D illustrate tables that are implemented during the generation of the AVF file and DUT file data in accordance with one embodiment of the present invention.
FIG. 7A illustrates a more detailed description of the sub-method operations of an operation of FIG. 3 where output enables are defined for each pin or pad in the chip design, in accordance with one embodiment of the present invention.
FIG. 7B illustrates an example of an AVF data conversion truth table, in accordance with one embodiment of the present invention.
FIG. 8A illustrates the method operations performed when timing data is generated for the production of the DUT file in accordance with one embodiment of the present invention.
FIG. 8B is a table illustrating an exemplary statement timing calculation in accordance with one embodiment of the present invention.
FIG. 9 illustrates a more detailed flowchart diagram of the method operations performed in FIG. 3 when generating a display statement in accordance with one embodiment of the present invention.
FIG. 10 illustrates a flowchart diagram of an AVF test vector verification loop in accordance with one embodiment of the present invention.
FIG. 11A illustrates a flowchart identifying the operations performed during AVF data verification in accordance with one embodiment of the present invention.
FIG. 11B illustrates pictorial examples of a multitude of tests that may be run as part of the test files in order to stimulate the chip design under test, in accordance with one embodiment of the present invention.
FIG. 12 illustrates a flowchart that describes the generation of a Verilog environment file that is subsequently executed in an operation of FIG. 11A, in accordance with one embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
An invention for generating test vectors for use on a physical test station to test a packaged integrated circuit design, and verifying the generated test vectors to ensure that the generated test vectors will actually generate the proper test result data once used on the physical test station. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be understood, however, to one skilled in the art, that the present invention may be practiced 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.
As discussed above, FIG. 1 illustrates a test station 10 that is typically used in testing integrated circuit devices. The test station 10 typically includes a computer station which is coupled to a unit that has a loadboard 14 . The loadboard 14 , as is well known in the art, is used to receive integrated circuit devices 12 . By the time testing is performed on the test station 10 , the integrated circuit device 12 will be in a packaged form and has the proper package pins that will communicate with appropriate electrical receptacles on the loadboard 14 . The following description will therefore detail the computer process implemented in automating the generation of test vectors and the automated verification of the test vectors before they are transferred to the test station 10 for use in testing the packaged circuit device 12 . Section A will therefore describe the automated generation of the AVF file data and DUT timing file data (e.g., that includes the execution of avfgen and avf.v), and section B will describe the automated verification loop (e.g., that includes the execution of avf2vlg) that is executed to verify the generated AVF file data.
A. Automated AVF and DUT Data Generation
FIG. 2 illustrates a flowchart 100 that details the operations performed in generating an AVF file, a DUT file, and a log file in accordance with one embodiment of the present invention. The method begins at an operation 102 where a chip design is provided for testing along with a netlist for the chip design. Also provided are testing parameters for the chip design, such as the file names for the chip design, the file name for the netlist, whether or not debugging information will be generated along with the file, instantiations for the chip and the I/O pads, the pin number for the power-on reset pin, etc.
Once these testing parameters have been provided in operation 102 , the method will proceed to an operation 104 where a map file is provided for the chip design. As will be described below with reference to FIGS. 5A through 5C, the map file will identify a port/pin map list for each of the multiple port cells. Accordingly, for each multi-port cell, the instance for the cell, the ports for the cell, the enable information for the cell, and the pin numbers for the cell will be generated as an entry in the map file. Once a map file having a plurality of entries for each of the multi-port cells is provided, the method will proceed to an operation 106 .
In operation 106 , an AVF generator (avfgen) is provided, which is configured to be executed by using the information provided in operations 102 and 104 . The method now proceeds to operation 108 where the AVF generator is executed to produce an “avf.v” file, which is a Verilog executable file. The avf.v file is then provided as part of a test bench for testing the target chip design. As shown, the test bench will generally include test files 110 a , the avf.v file 110 b , a netlist 110 c for the chip design, and a set of models 110 d . The test files 110 a include information that details the wiring information for interconnecting the chip design to the set of models 110 d . In addition, the test files 110 a also include information that will detail the commands that are designed to stimulate the chip design under test and in accordance with the appropriate timing.
It should be noted that the avf.v file 110 b is a generic file that will work with all of the tests provided in the test files 110 a . Once the test bench has been established, the method will proceed to make the test bench information accessible to operation 112 , where the test bench is executed to generate an AVF file 114 , a DUT file 116 , and a log file 118 .
FIG. 3 illustrates a flowchart 200 which illustrates the execution of the AVF generator that is configured to produce the avf.v file as described with reference to 108 of FIG. 2 . Initially, the method begins at an operation 202 where the command line is set up to generate an avf.v file using a netlist of the chip design. As mentioned above, the avf.v file can then be subsequently executed along with a test bench in order to generate the desired AVF file and the DUT file.
Setting up the command line generally entails typing in the correct data to enable running the AVF generator and a desired chip design, and its associated instantiations, map file, and netlist. FIG. 4A illustrates the typically commands that may be provided in a command line when it is desired to generate the avf.v file. As shown, a command line 202 a is provided with a reference to avfgen and associated commands for running the AVF generator. The typical commands include, -V, -P, -0 FILENAME, -M FILENAME, -N FILENAME, -T TOP INSTANCE, -I IOPAD INSTANCE, and -R RESET PIN NUMBER. These identifying commands will therefore assist the AVF generator in producing the proper avf.v file for the desired chip design and associated netlist. FIGS. 4B and 4C illustrate a more simplified example of a chip design 226 and an associated command line entry. For example, the chip design 226 includes associated instantiations for u_top 232 , u_iopad 234 , and u_top.x 236 . These example instantiations identify some characteristics for this simplified chip design 226 . Accordingly, the command line entry referenced in 202 a of FIG. 3 for the simplified chip design 226 would read as shown in FIG. 4 C.
Referring once again to FIG. 3, once the setup of the command line is complete, the method will proceed to execute the AVF generator to produce the avf.v file in operation 108 . The generation of the avf.v file begins at an operation 204 where a map file is read into memory for the desired chip design. Next, the method will proceed to an operation 206 where the netlist for the chip design is read in order to generate a list of pins based in part from data in the map file that is stored in memory. Once the list of pins have been generated in operation 206 , the method will proceed to an operation 208 where output enables for each pin in the chip design are identified.
The method now proceeds to an operation 210 where an AVF data conversion function is defined that considers output enabled data, current pin values, and power-on reset states. Once the AVF data conversion function has been defined in operation 210 , the method will proceed to an operation 212 where the list of pins stored in memory are retrieved to generate code that produces timing for a DUT file for each pin in the list of pins. The method now proceeds to an operation 214 where a large display statement (i.e., a Verilog statement) is produced to enable the generation of a line of the AVF file for a particular cycle. In general, generating a display statement includes, performing a function call (for each pin) to the AVF data conversion table (i.e., FIG. 7 B), and then taking the result from the function call and placing it into the proper entry location in the AVF file.
After the large display statement has been produced in operation 214 , the method proceeds to an operation 216 where a DUT creation code is generated. As will be described below, the DUT creation code is configured to produce the DUT file once the avf.v file produced in 108 is executed along with the test bench. Once the DUT creation code has been generated in operation 216 , the method of flowchart 200 will be done. As described above with reference to FIG. 2, the avf.v file 110 b and other test bench files may then be executed to generate the AVF file 114 , the DUT file 116 , and the log file 118 .
Accordingly, the avf.v file that is produced when the AVF generator is executed, may be used with any number of test files 110 a and associated models 110 b , in order to test the true functionality of the chip design under test. Reference may be made to Appendix A, which is an exemplary AVF file that may be generated once the test bench for a particular design is executed. Appendices B-1 through B-3 illustrates an exemplary DUT file 116 that may also be generated when the Verilog test bench executable files are executed.
FIG. 5A illustrates a flowchart 250 that identifies the method operations performed in generating a map file for a particular chip design in accordance with one embodiment of the present invention. The method begins at an operation 252 where cell types and their associated logical functionality are identified from the netlist of the chip design. Once the cell types and their associated logical functions have been identified, the method will proceed to an operation 254 where the method will proceed to a next multiple I/O cell in the netlist for the chip design.
Initially, the method will go to the first multiple I/O cell. Once at the first multiple I/O cell, the method will proceed to an operation 256 where the multiple I/O cell is formatted in an identifying statement. FIG. 5B illustrates one example of a multiple I/O cell that may be part of the chip design. In the example of FIG. 5B, an instance of an oscillator (u_OSC) is provided having a dataport 1 and a dataport 2. The multiple I/O oscillator is shown having a first pin and a second pin. The first pin is assigned pin number 34 , and the second pin is assigned pin number 35 . Dataport 1 of the first cell is shown having output enabled data .ned 1, and .neu 1. Dataport 2 is shown having output enabled data .ned 2 and .neu 1.
Therefore, for this exemplary multiple I/O cell of FIG. 5B, the identifying statement formatted in operation 256 is shown in FIG. 5C as 256 ′. This exemplary map file entry will therefore identify the oscillator as being a multiple I/O cell, which is part of the netlist. The method will now proceed to an operation 258 where it is determined if there is a next cell. If there is a next cell, the method will proceed to an operation 252 where the cell types and their associated logical functionality are identified. Now, the method will again proceed to operation 254 where the method will move to the next multiple I/O cell in the netlist for the chip design. Once the next multiple I/O cell in the netlist for the chip design is identified, it will be formatted in a proper identifying statement in operation 256 . This method will therefore continue until there are no more multiple I/O cells in the netlist. At that point, the method of generating a map file 250 will be complete.
FIG. 5D is a flowchart 270 illustrating the method operation performed in generating a map file for all I/O cells including single port cells and multi port cells, in accordance with one embodiment of the present invention. The method begins at an operation 272 where all cell types and their associated logical functionality are identified. Once all cell types have been identified, the method will proceed to an operation 274 where the method will proceed to a next cell type in the list of I/O cells. Initially, the method will begin with the first cell in the list of I/O cells. Then, the method will proceed to a decision operation 276 where it is determined whether the current cell is either a single port or a multi-port cell.
If the current cell is a single-port cell, the method will proceed to an operation 278 where an output-enable equation for the current single-port cell type is generated. Once the output-enable equation has been generated, the method will proceed to an operation 280 where the port name associated with the signal name is input into the map file. Specifically, this operation informs the program where to look for the signal name. This is needed because for each cell type, the signal name will be at a different port. Once operation 280 has been performed, the method will proceed to a decision operation 282 where it is determined whether there are anymore cells in the list of I/O cells. If there are no more cells, the method will be done. Alternatively, if there are more cells, the method will proceed back to operation 274 .
Assuming now that the current cell in decision operation 276 is a multi-port cell, then the method will proceed to an operation 284 . In operation 284 , an output-enable equation will be generated for the current pin/pad of the multi-port cell type. Next, the method will proceed to an operation 286 where the port name associated with the signal name for a current port is input into the map file. Once the input has been performed for the current port, the method will proceed to a decision operation 288 where it is determined whether there are anymore ports in the current multi-port cell. If there are, operations 284 and 286 will be repeated for each port in the multi-port cell. Once all ports have been completed for the multi-port cell, the method will proceed to decision operation 282 where it is determined if there are anymore cells in the list of I/O cells. If there are, the method will again proceed back up to operation 274 where the next cell type will be identified. Alternatively, if it is determined in operation 282 that there are no more cells in the I/O cell list, the method will be done.
An example of the map file entries for single port and multi-port cells is shown in Table A below. Specifically, an example for a single port cell and a multi-port cell have been provided, including the output-enable equations and the pin names.
TABLE A
Exemplary Map File Entries For Single/Multi Port Cells
Cell Type
Single/Multi
Output-Enable Equation
Pin Name
Single port cell
ioej08
S
“{NED} && {NEU}”
{PAD};
: :
:
: :
:
Multi port cell
ioaj06
M
“!{OEN} && {SESEL}”
{PADP}
“!{OEN}”
{PADM};
: :
:
: :
:
FIG. 6A illustrates an example of the method operations performed in generating a list of pins for the chip design in accordance with one embodiment of the present invention. Accordingly, flowchart 206 is a more detailed description of the method operations performed in operation 206 of FIG. 3 . The method will begin at an operation 302 where parsing of the netlist of the chip design will be performed to identify the I/O module. FIG. 6B illustrates an example of a port/net table 302 ′ of the netlist for the chip design that may be parsed through during operation 302 . As shown, the exemplary table 302 ′ identifies an instance, a cell type, a port and net for the enable information and the signal information, respectively. Once the I/O module has been identified in operation 302 , the method will proceed to an operation 304 where the first line in the I/O module is read. Once the first line in the I/O module is read in operation 304 , the method will proceed to a decision operation 306 where it is determined if the current line is for a pin or a pad (as used herein, the pin and pad terms are interchangeable).
If it is not for a pin or a pad, then it is most likely some other type of logical gate. At that point, the method will proceed back to operation 304 where the next line in the I/O module is read. Once again, the method will proceed to decision operation 306 where it is determined if the current line is for a pin or a pad. When it is determined that it is for a pin or a pad, the method will proceed to an operation 308 where a table identifying port and net for the current pin or pad is generated. As shown in FIG. 6C, table 308 ′ illustrates an example of the generated table for the port and net. The port will identify the output enable data (e.g.,.neu, ned, etc.), and net data will identify the signal data (e.g., signal 1 , signal 2 , etc.). In this embodiment, the generated table 308 ′ of FIG. 6C will be generated for each line in the I/O module, and then erased from memory. The data in FIG. 6C therefore corresponds to PAD001 in FIG. 6B where the appropriate port and net data is illustrated. When the next line in the I/O module is read, table 308 ′ will be generated anew for the current line.
From operation 308 in FIG. 6A, the method will proceed to a decision operation 310 where it is determined if the current pin or pad is associated with a map cell. As mentioned above, map cells are cells that have multiple I/O ports. If the current pin is for a map cell, the method will proceed to an operation 312 where reference will be made to the map file and the pin or pad is identified.
Once the pin or pad in the map file has been identified for the map cell, the method will proceed to an operation 314 where a pin or pad entry is created for each port. Reference is now drawn to FIG. 6D where an example of a port pin/pad entry table is provided. The entry table therefore identifies a port name, a pin or pad number, output enable data, and associated signals. For the exemplary multiple I/O cell of FIG. 5B, the port pin/pad entry table will have an entry for dataport 1, dataport 2, and its associated parameters. These entries will be made in operation 314 of FIG. 6 A. On the other hand, if it is determined in operation 310 that the current pin or pad is not for a map cell, the method will proceed to an operation 316 where one entry for the single port is created. As an example, FIG. 6D illustrates a single entry for a pad having a pin or pad number 1 and its associated output enable data and signal data.
At this point, the method will proceed from either operation 314 or 316 to a decision operation 318 . In decision operation 318 , it is determined whether there is a next line in the I/O module. If there is, the method will proceed back to operation 304 where the next line in the I/O module is read. As mentioned above, an example of a simplified I/O module is shown in FIG. 6 B. The method will then proceed filling-in the port pin or pad entry table of FIG. 6D until each line of the I/O module has been read and processed in FIG. 6A to generate a list of pins for the chip design.
FIG. 7A illustrates a more detailed description of the method of operation 208 of FIG. 3 where output enables are defined for each pin or pad in the chip design. The method begins at an operation 350 where the method will go to a next entry in the pin or pad entry table of FIG. 6D, once it has been completed during the method operations of the flowchart of FIG. 6 A. The method will now proceed to a decision operation 352 where it is determined whether the entry is empty because it is a deleted power pin. If it is a deleted power pin, the method will skip the entry in operation 356 and proceed back to operation 350 . In operation 350 , the method will go to the next entry in the port or pin entry table. Once it is determined that the next entry is not empty in operation 352 , the method will proceed to an operation 354 where the signals in the port or pin entry table are used to generate wire statements. Exemplary wire statements, familiar to those skilled in the art are shown in Appendix C for completeness.
FIG. 7B illustrates an example of an AVF data conversion table which is defined in operation 210 of FIG. 3 . As shown, the AVF data conversion table is used to determine what the AVF data is supposed to be depending upon the power-on reset information, the output enable information, and the value for each pin in a particular cycle.
FIG. 8A illustrates the method operations performed when timing data is generated for the production of the DUT file. The method begins at an operation 402 where the method proceeds to the next entry in the port or pin entry table which was defined in FIG. 6 D. In operation 404 , it is determined whether the entry is empty because it is a deleted power pin. If it is a deleted power pin, the method will proceed to an operation 410 where the entry is skipped and the method will proceed back to operation 402 . When it is determined that the current entry in the port or pin entry table is not deleted, the method will proceed to an operation 406 where a statement timing calculation is provided to the AVF file.
Next, the method will proceed to an operation 408 where the current pin name is inserted into the statement timing calculation. FIG. 8B provides an exemplary statement timing calculation in accordance with this embodiment. At this point, the method proceeds to a decision operation 412 where it is determined if there is a next pin in the entry table. If there is, the method will again proceed to operation 402 . If there are no more pins in the entry table, the method will be done.
FIG. 9 illustrates a more detailed flowchart diagram of the method operations performed in 214 of FIG. 3 when generating a display statement in accordance with one embodiment of the present invention. The method begins at an operation 420 where the method moves to the next entry in the port/pin entry table. The method now moves to an operation 422 where it is determined if the entry is empty because it is a deleted power pin. If it is, the method proceeds to an operation 424 where the entry is skipped and the method moves to operation 420 . Once it is determined that the entry is not empty because it was not a deleted power pin, the method will proceed to an operation 426 .
In operation 426 , an AVF data conversion function call is generated for the current pin entry using output enable data (wire statements), value data (port name), and power-on reset data. Reference should be made to the exemplary output enable data, value data, and power-on reset data provided in the table of FIG. 7 B. The AVF data conversion function call is essentially the call that will generate AVF data similar to the AVF file illustrated in Appendix A, once the avf.v file along with the test bench (which are Verilog executables) are executed. Next, the method proceeds to an operation 428 where it is determined if there is a next pin. If there is a next pin, the method will proceed back to operation 420 . From operation 420 , the method will again proceed to decision operation 422 and then to skip the current entry 424 if the entry is empty because it is a deleted power pin. If it is not a deleted power pin, the method will again proceed to operation 426 and then back to operation 428 . Once there are no more pins, the method will be done.
B. AVF Vector Data Verification Loop
FIG. 10 illustrates a flowchart diagram of an AVF test vector verification loop 500 in accordance with one embodiment of the present invention. As discussed above, the verification loop is performed to substantiate the correctness of the generated AVF file data and the DUT file data that has just been generated. By executing this verification loop, the generated AVF file data and the DUT file data are used to generate input vector data and expected output vector data. The input vector data is then provided to a digital model of the test station having a model of the chip design under test. The input test vector is then feed to the model test station, which then generates an output that is compared with an expected output. If the output from the model test station matches the expected output, then the AVF file data and the DUT file data will be ready for use in the physical test station.
Reference is again made to FIG. 10, where the verification loop begins at an operation 502 and a test bench is provided. As discussed with reference to FIG. 2 above, the test bench typically includes the generated avf.v file 110 b , test files 110 a , the netlist for the chip design being tested 110 c , and models 110 d . Therefore, once the test bench is provided, the test bench files are executed in 112 to generate the AVF file 114 and the DUT file 116 .
However, to ensure that the generated AVF file 114 and DUT file 116 are accurate once they are provided to the physical test station, they are processed through the verification loop. In this process, the AVF file 114 and the DUT file 116 are provided to a block 504 (e.g., av2vlg) where the AVF file and the DUT file are processed for use in the verification loop. During the processing, input test data (.invec) 508 , output test data (.outvec) 510 , and an.env file 506 (e.g., which is an environment file) are produced. In general, the invec 508 is provided to the.env file 506 which has information about a model of a standalone chip which is simulated on a model test station 512 . The.outvec 510 is essentially the expected outputs that should be generated once the.env file 506 is executed.
Once the.env 506 is executed, an actual output will be provided to a comparator 514 . The.outvec 510 , which is the expected output, is also provided to the comparator 514 . If the expected output and the actual output match, then the AVF file is ready for use in the actual physical test station. However, if a match is not produced by the comparator 514 , the loop will continue to a block 518 where the test file data of the test bench is modified to fix any timing errors that may have caused the “actual output” to not match the “expected output.”
After the modification to the test file has been performed, the loop will again cause the test bench to be executed to generate another AVF file 114 and another DUT file 116 . The AVF test vector verification loop 500 will therefore continue to be processed (if desired by the test engineer, because less than a perfect match may be acceptable in certain cases) until the comparator 514 determines that the actual output coming from the standalone chip on the model test station 512 , matches the expected output from the.outvec 510 . At that point, the AVF file should function properly with the actual physical test station hardware and properly test the integrity of the chip design being tested. In another embodiment, each time a test of the test files is run, the results of the verification are provided to a test result log 517 (which may be a long log of all of the run tests). In one embodiment of the present invention, a test engineer can examine the test result log 517 and determine if the verification loop should be run again after modifications are made to the test file data of the test bench.
It should also be noted that because the standalone chip on the model test station is actually a computer model of the test station, complete test coverage testing can also be performed during the model testing stage. As can be appreciated, this a substantial advance in the art.
FIG. 11A illustrates a flowchart 504 identifying the operations performed during AVF data verification in accordance with one embodiment of the present invention. The method begins at an operation 550 where the method will go to a first test that is identified in the test files 110 a in a particular test bench. Thus, FIG. 11B illustrates a plurality of tests which may be run during verification of the AVF data. For example, a first test may include a test 1 .invec file, a test 1 .outvec file, and a test 1 .env file. The first test may be, for example, to test the interaction of the chip design with a given microprocessor. A second test may be to test the interaction of the chip design with a hard disk drive. A third test may be to test the chip design's interaction with a DVD player. Of course, the test files 110 a may include many more tests in the range of hundreds or even many thousands of different tests to test the interaction of the chip design with its expected real world stimulation when the packaged chip is used for its intended purpose.
Reference is again drawn to FIG. 11A where the method continues in operation 552 where an AVF file and a DUT file is provided, and a chip file for the verification of generated AVF and DUT data is made available. Reference may be made to Appendix D which identifies an exemplary chip file. The chip file includes an identification of a netlist, pullup data, external signal names (e.g., chip wiring to external components), and bus declarations. Once the AVF file, the DUT file, and the chip file have been provided for verification in operation 552 , the method will proceed to an operation 554 . In operation 554 , the method will parse through the chip file to extract netlist information, external signal name information, bus definition information, and pullup information.
Once the parsing through the chip file has been completed, the method will proceed to an operation 556 where a parsing through the DUT file to extract I/O information, channel member information, and timing information is performed. As mentioned above, an exemplary DUT file is shown in Appendices B-1 through B-3. The method then proceeds to an operation 558 where the AVF file data is split into input data (.invec), and output data (.outvec). After the AVF data has been split, the method will proceed to an operation 560 where a Verilog.env file is generated that simulates the test station (i.e., the physical tester) using a standalone test bench. The standalone test bench will basically include the netlist for the chip design being tested.
Next, the method will proceed to an operation 562 where the Verilog.env file is executed using the input data and the output data. With reference to FIG. 10, the .env file 506 is executed using the standalone chip on the model test station 512 , including the comparator 514 . Once executed, a determination is made as to whether the expected output matches the output from the standalone chip on the model test station. At this point, the method will proceed to a decision operation 564 where it is determined if there is a next test. As shown in FIG. 11B, there are typically many more tests that are run during the verification stage.
Accordingly, for the next test, the method will proceed back up to operation 550 where the method will go to the next test. Once it is determined that there are no more tests, a log is generated identifying any errors in the tests in operation 566 . At this point, the test engineer can analyze the generated log to determine if any of the errors should be fixed in operation 568 . If fixing the errors is desired, the method will proceed to an operation 570 where a test file having a particular error is located. Once the test file is located, the method will proceed to operation 572 where the test file errors are fixed to attempt to eliminate miscompares. Once the test file errors have been fixed, the method will proceed to operation 574 where the method will return to operation 112 of FIG. 2, where the test bench is executed. The execution of the test bench is also pictorially shown in FIG. 10 .
At that point, a new AVF file and DUT file are generated, and verification of the AVF data can again be performed, if desired. Alternatively, if it is determined in operation 568 that there are no errors to fix, it will be assumed that the execution of the .env file produced actual outputs from the standalone chip on the model test station that matched the expected outputs. In that case, the method will be done. At the same time, if the errors are such that further verification is not desired, the method will also be done from the determination of operation 568 .
FIG. 12 illustrates a flowchart 560 that describes the generation of a Verilog .env file that is subsequently executed in operation 562 of FIG. 11 A. The method of generating a Verilog .env file begins at an operation 572 where wire statements for each input of the chip design are generated. Next, the method will move to an operation 573 where each input pin is assigned to a pin column of the invec file. In general, the .invec file is arranged in a memory array having columns for each pin in the chip design, and a row number for each cycle in a test. Next, the method will proceed to an operation 574 where wire statements for each output of the chip design is generated.
Once wire statements have been generated, the method will proceed to an operation 575 where each output wire is assigned to a pin column of the.outvec file. The method now proceeds to an operation 576 where Verilog code configured to read the invec and.outvec data into memory is generated. Once that set of code is generated, the method will proceed to an operation 578 where Verilog code configured to load capacitance information for the chip design is generated. As is well known, the chip wiring has particular capacitance for the various wires that should be approximated during the modeling of the chip design in order to approximate the actual true physical chip design circuit. Next, the method will proceed to an operation 579 where Verilog code configured to generate an input delay statement for inputs is generated. Verilog code is also generated to assign an input-delay wire to a current pin. An example of an input-delay wire is shown below.
wire #delay signalname_drv=signalname_input
Typical input-delay statements of the present invention can handle non-return to 0, return to 1, and return 0 statements. In the above example, each time the “signalname_input” changes, the “signalname_drv” will also change after a given “delay” that is specified in the input delay wire statement.
The method will then proceed to and operation 580 where Verilog code configured to generate a Zycad file is generated. The Zycad file is a fault creating file that applies inputs and can determine what amount of test coverage is achieved during a particular test. This test coverage testing will, therefore, closely if not identically, approximate the test coverage achieved in the true integrated circuit device being tested on the physical test station.
From operation 580 , the method will proceed to an operation 581 where Verilog code configured to compare outputs at a strobe time and generate an error if a miscompare is detected, is generated. In this exemplary design, the strobe is set for 90 percent of a given cycle. Next, the method will proceed to an operation 582 where Verilog code configured to instantiate the chip design and wire each pin of the chip to its associated driving wire, is generated.
At this point, the method will proceed to an operation 583 where Verilog code will assign a pullup to each pin that is configured to have a pullup according to the chip file, is generated. Once the pullup information has been configured, the method will proceed to an operation 584 where Verilog code configured to generate an undertow file is generated. An undertow file is one that can be executed using a well known undertow program that enables computer graphical inspection of signals to facilitate debugging of errors. At this point, the method will be done. As mentioned above, the .env file generated in flowchart 560 is then subsequently executed along with the standalone chip on the model test station and the invec data to determine whether the output produced from the standalone chip on the model test station will match the expected output (i.e.,.outvec).
If a match is achieved, the AVF file data and the DUT file data will be considered to be appropriate for running on the physical test station. However, if the comparison determines that the actual outputs do not match the expected outputs, a test log will be generated for each of the files identifying where errors in comparisons were detected. At that point, the test engineer can decide whether further loops through the AVF test vector verification loop 500 of FIG. 10 should be executed in order to produce a suitable AVF file for use on the physical test station.
The present invention may be implemented using any type of integrated circuit logic, state machines, or software driven computer-implemented operations as described above. By way of example, a hardware description language (HDL) based design and synthesis program may be used to design the silicon-level circuitry necessary to appropriately perform the data and control operations in accordance with one embodiment of the present invention. Although any suitable design tool may be used, a hardware description language “Verilog®” tool available from Cadence Design Systems, Inc. of Santa Clara, Calif., is used.
The invention may employ various computer-implemented operations involving data stored in computer systems. These operations are those requiring physical manipulation of physical quantities. Usually, though not necessarily, these quantities take the form of electrical or magnetic signals capable of being stored, transferred, combined, compared, and otherwise manipulated. Further, the manipulations performed are often referred to in terms, such as producing, identifying, determining, or comparing.
Any of the operations described herein that form part of the invention are useful machine operations. The invention also relates to a device or an apparatus for performing these operations. The apparatus may be specially constructed for the required purposes, or it may be a general purpose computer selectively activated or configured by a computer program stored in the computer. In particular, various general purpose machines may be used with computer programs written in accordance with the teachings herein, or it may be more convenient to construct a more specialized apparatus to perform the required operations.
Although the foregoing invention has been described in some detail for purposes of clarity of understanding, it will be apparent that certain changes and modifications may be practiced within the scope of the appended claims. Accordingly, the present embodiments are to be considered as illustrative and not restrictive, and the invention is not to be limited to the details given herein, but may be modified within the scope and equivalents of the appended claims. | Disclosed is a method for generating AVF test file data for use in testing a simulation of an integrated circuit design, and verifying the generated AVF test file data before they are delivered to a physical silicon version of the integrated circuit design. The generation method includes providing a map file that contains a plurality of identifying statements for each multiple port I/O cell (or also including single port I/O cells) in the integrated circuit design. Then, generate a verilog executable file for the integrated circuit design. The verilog executable file is configured to contain data associated with the map file, a netlist of the integrated circuit design, output enable data derived from the netlist, and AVF data conversion information. The method further comprises executing the verilog executable file along with a test bench that includes the netlist of the integrated circuit design, a set of test files, and models. The execution is configured to produce the AVF test file data and a DUT timing file data. The generated data is then processed through a verification loop that is configured to identify in a log all of the possible errors with the generated test data. The input data used to generate the AVF test file data may then be modified to enable the re-generation of new AVF test file data and new DUT timing file data. If errors are still present, the loop may again be re-run, if the errors are of the kind that would necessitate correction. Once the verification loop has been run to the satisfaction of the test engineer, the test vector data can be applied to the physical test station for use on the physical silicon chip. | 6 |
[0001] This invention is called PISTON ROTARY PUMP OF VARIABLE FLOW. Is a mechanical device destined to impel and/or to compress fluids through the action of a piston guided by driven rotary parts, delineating a rotary movement and at the same time a king pin or pendulum within a stator contention case, arranging the chambers that compress and expand during its performance.
SEVERAL VIEWS OF THE DRAWINGS-BRIEF DESCRIPTION
[0002] FIG. 1 : Lay out view of the pump in its two models or construction varying.
[0003] FIG. 1Y : Model or varying Y
[0004] FIG. 2X : Model or varying X
[0005] FIG. 2 : Cross-section in front and back of the pump in its two varying or constructions models.
[0006] FIG. 2Y : Varying Y
[0007] FIG. 2X : Varying X
[0008] FIG. 3 : View of the working development of the pump in its two varying or construction models:
[0009] FIG. 3Y (AY, BY, CY): Varying Y
[0010] FIG. 3X (AX, BX, CX): Varying X
[0011] FIG. 4 : Cross-Section in front A and side B of the transference device from the cneter or rotation point of the secondary conductor rotor part.
DETAILED DESCRIPTION OF THE INVENTION
[0012] This invention represent a PISTON ROTARY PUMP OF VARIABLE FLOW, is submitted in two models or construction varying: Y and X, FIG. 1 ( FIG. 1Y , FIG. 1X ), FIG. 2 ( FIG. 2Y , FIG. 2X ), FIG. 3 ( FIG. 3Y , FIG. 3X ). Said pump is composed by a case 5 Y ( FIG. 1Y ) or 5 X ( FIG. 1X ) of cylindrical hole 8 Y ( FIG. 1Y ) or 8 X ( FIG. 1X ), with an internal circular stator wall HY ( FIG. 1Y ) or HX ( FIG. 1X ), where a piston runs inside, 11 Y ( FIGS. 1Y, 2Y , 3 Y) or 11 X ( FIGS. 1X, 2X , 3 X) showing a rotation movement and at the same time a king pin or pendulum movement, due that is driven by two conducting rotary parts, one is the principal conducting rotary part 12 Y ( FIGS. 1Y, 2Y , 3 Y) or 12 X ( FIGS. 1X , 2 X) which has a rotary center that coincides with the center of the internal hole of the case and takes the piston in a coupling or junction point movable or articulated, UY ( FIGS. 1Y, 2Y , 3 Y), or UX ( FIGS. 1X, 2X , 3 X), and a secondary conducting rotary part 10 Y ( FIGS. 1Y, 2Y , 3 Y) or 10 X ( FIGS. 1X, 2X ) that has a rotation center 9 Y (FIGS. 1 Y, 2 Y,) or 9 X ( 1 X, 2 X) exocentric with the case hole center, taking the piston in a coupling or junction point movable or articulated SY ( FIGS. 1Y, 2Y , 3 Y) or SX ( FIGS. 1X, 2X , 3 X).
[0013] The pump, in its two models or construction varying, keeps always the same functioning concept, which is the characteristics of the invention that covers a piston with rotary movement together with a king pin or pendulum within the stator contention case driven by the two rotary parts, one part rotates with the rotation center of the circumference of the case hole and the other rotates keeping an exocentric rotation center with the center of the circumference of the case hole. Being, said center, variable in its location, which allows modifying the volume of flow of the fluid that impels the pump.
[0014] Therefore, the constructive difference between the two models or varying the pump do not affect the performance, basic characteristics or fundamentals of the invention, which are only secondary and minor modifications in the structure of some of the pump components.
[0015] In the model or varying Y of the pump, the principal rotor conducting part 12 Y has a bell shape which in its cross-section or outside shape coincides exactly with the cylindrical hole of the case 8 Y, and in the cross-section or perimeter inside the section of its internal hole, is located the piston 11 Y, which has the shape of an irregular circumference that follows the running of the king pin or pendulum of said piston.
[0016] The par 12 Y has ports 14 Y that allow the flow of the fluid, because this part acts as a rotary valve, which is clearly appreciated in FIG. 3 .
[0017] In the case of the varying or model X, the principal rotary conducting part 10 X has the shape of a lever that fits in a hole or depression, adequately, that has one side of the piston 11 X dividing said hole in two independent chambers between them, RX and PX ( FIG. 3X ) that compress and expands during the running of the piston and interact with the principal chambers LX and MX ( FIG. 3X ), arranged between the piston and the stator case hole, allowing the flow of fluid of the principal chambers to the port of exit 15 X ( FIG. 1X ) or entry port 15 BX ( FIG. 1X ) to the corresponding principal chamber, whichever the case, through the ports 14 X ( FIG. 1X ) located at both sides of the piston 11 X. In this case the rotor part 11 X, has the function of a rotary valve, opening and closing the entrance and exit ports 15 BX and 15 X of the pump. The piston 11 X requires sealing parts 16 X and 16 BX ( FIGS. 1X, 2X , 3 X) that are set up in grooves in both ends of the piston 11 X and using springs 17 X and 17 BX ( FIG. 1X ), allow the proper adjustment of the piston with the inside walls of the stator HX of the case, covering the separation produced between both, during pendulum displacement or king pin of the piston, reaching this way to divide the hole of the case in two independent chambers between them LX and MX ( FIG. 3X ).
[0018] The pump has a device to move the rotation center of the secondary conductor rotor part 10 Y or 10 X ( FIG. 4 ) composed of a body 3 that bears the rotor shaft of the secondary conductor rotor part E, which runs in a contention groove K moved by a threaded shaft 1 which is inserted in a port 5 with female thread located in body 3 , being the threaded shaft 1 fasten by a contention part 7 with a steering wheel 2 at one end to transmit movement through an outside gear.
DESCRIPTION OF THE PERFOMANCE OF THE PUMP
[0019] The pump works as follows: the piston inside the stator case is driven by the principal conductor rotor part that rotates within the case, coinciding its rotation center with the center of the circumference of the case hole, therefore, the piston makes a revolving movement within the case, but as is connected to a secondary conductor rotor part, that has an exocentric rotation center with respect to the center of the circumference related to the cylindrical hole of the case, the piston moves as well in a king pin or pendulum at the same time, being the center or partial rotation of the pendulum movement of the piston, the coupling of the piston with the principal conductor part UY or UX. Said king pin movement, added to the rotation movement, is due to the fact that the piston works as a bond between the principal rotor part and secondary rotor part, because when the principal conductor rotor part pulls through the piston the secondary rotor part, however, as the secondary rotor part has a different rotation center than the principal rotor part and is exocentric with respect to the case hole, moves in its end where the piston is fasten, a variation in the approach to the stator wall HY or HX of the inside hole of the case, displacing from a minimum to a maximum distance and vice versa in the rotation of the parts, unlike of the principal conductor rotor part that has a centralized rotation center with the circumference of the case hole, its end fasten to the piston keeps always the same distance of approach with the stator inside wall of the case, there is a variation in the angle between the imaginary axis that divides symmetrically the piston all along, and the imaginary axis that joints the coupling point of the principal rotor part with the piston and the rotary axis of the same, as if the secondary rotor part virtually pull and push the piston, which results in the king pin or pendulum movement of the piston.
[0020] As the piston divides the hole of the case in two chambers, GX and FX, or LX and MX ( FIG. 3 ), when tilt to the right due to the king pin movement, close or compress the chamber located to the rigth GY ( FIG. 3Y (AY)) or LX ( FIG. 3X (AX)) and expands the one to its left FY ( FIG. 3Y (AY)) or MX ( FIG. 3X (AX)), and when changing to the contrary, that is to say tilt to the left, compress the chamber to the left FY (Fig. CY) or MX (Fig. CX) and expands to the right GY (Fig. CY) or LX (Fig. CX) Therefore, in a rotation of the principal conductor rotor part driving the piston, it expands and compress the two chambers LX, and MX or GY and FX, each at its respective time.
[0021] The pump has at the entrance and exit of the fluid of the respective ports of entry and exits 15 BY and 15 Y ( FIG. 1Y ) or 15 BX and 15 X ( FIG. 1X ), wich can be opened and closed alternatively by the principal conductor rotor part which has also the function rotary valve, when rotating.
[0022] Other component parts of the pump indicated in the drawings are: the cover 4 Y or 4 X ( FIG. 1 ) and the entrance and exit ducts of the fluid 7 BY and 7 X, or 7 BX and 7 X ( FIG. 1 ).
[0023] In all drawings is used the same code for the same part or component. | This invention called PISTON ROTARY PUMP OF VARIABLE FLOW. Is a mechanical device destined to impel and/or to compress fluids through the action of a piston guided by driven rotary parts, delineating a rotary movement and at the same time a king pin or pendulum movement within a stator contention case, arranging the chambers that compress and expand during its performance. The pump flow vary thru a simple movement of the device that support the rotation axle of one of the rotary parts. | 5 |
BACKGROUND OF THE INVENTION
A variety of methods have heretofore been used or proposed for use in applying metallic platings to all or portions of the surfaces of polymeric plastic parts. Such processes conventionally comprise a plurality of sequential pre-treatment steps to render the plastic substrate receptive to the application of an electroless plating whereafter the plated part can be processed through conventional electroplating operations to apply one or a plurality of supplemental metallic platings over all or selected portions of the plastic substrate. Conventionally, the pre-treatment steps employed include a cleaning or series of cleaning steps, if necessary, to remove surface films or contaminating substances followed thereafter by an aqueous acidic etching step employing a hexavalent chromium solution to achieve a desired surface roughness or texture enhancing a mechanical interlock between the substrate and the metallic plating to be applied thereover. The etched substrate is subjected to one or a plurality of rinse treatments to extract and remove any residual hexavalent chromium ions on the surfaces of the substrate which may also include a neutralization step including reducing agents to substantially convert any residual hexavalent chromium ions to the trivalent state. The etched substrate is thereafter subjected to an activation treatment in an aqueous acidic solution containing a tin-palladium complex to form active sites on the surface of the substrate followed by one or more rinsing steps after which the activated surface is subjected to an accelerating treatment in an aqueous solution to extract any residual tin constituents or compounds on the surface of the substrate. The accelerated plastic part is again water rinsed and thereafter is subjected to an electroless plating operation of any of the types known in the art to apply a metallic plate such as copper, nickel or cobalt over all or certain selected areas thereof whereafter the part is rinsed and thereafter is subjected to conventional electroplating operations.
Typical of such plastic plating processes are those described in U.S. Pat. Nos. 3,622,370; 3,961,109; and 3,962,497 to which reference is made for further details of the process. The present invention is also applicable to processes of the foregoing type and is specifically directed to an improved aqueous accelerating solution which provides benefits and advantages heretofore unattainable in accordance with prior art practices.
A continuing problem associated with the electroplating of polymeric substrates has been in the careful control of the activation and accelerating steps to achieve a plastic substrate which is receptive to the subsequent electroless plating solution to provide 100% coverage of a conductive metal layer which is adherent to the substrate and which is devoid of any lack of continuity of coverage or "skipping". The presence of such discontinuities or skips results in plastic parts which upon subsequent electroplating contain non-plated areas or non-uniformity in the metallic plating deposit rendering them unsuitable for the intended end use.
It has been observed that etched and activated plastic substrates employing a tin-palladium complex activator which have not been accelerated or which have been subjected to an accelerating treatment in a weak accelerator will not become plated or will only become partially plated in the subsequent electroless plating step. Such parts are ordinarily referred to as being "under accelerated". On the other hand, when such parts are accelerated in an accelerating solution that is too strong or too aggressive, electroless plating is also adversely effected as evidenced by discontinuity or skips and in some instances no plating deposit at all. In such instances, the parts are referred to as being "over-accelerated". It is important, accordingly, that the accelerating solution employed be carefully controlled so as to provide the requisite degree of acceleration in order to achieve uniform continuous electroless plating deposits on a consistent basis.
It has been observed that accelerating solutions of the types heretofore known are extremely sensitive to the presence of contaminating metal ions carried over from other processing steps or inherently present in the accelerating solution. For example, hexavalent chromium ions in spite of vigorous rinsing and neutralization steps nevertheless are carried over into the subsequent accelerating solution by entrapment in the plastic parts being processed as well as by bleed-through from cracks or openings in the protective plastisol coating conventionally employed over portions of the work racks. Tin compounds similarly are carried over from the prior activation step which adversely affect the accelerating treatment. The presence of ferric and cupric ions in relatively low concentrations such as only 10 ppm and 20 ppm, respectively, have been found to significantly alter the agressiveness of the accelerating solution rendering it unsuitable for further use. Ferric ions constitute a normal contaminant in the water employed for preparing the several aqueous solutions and are further introduced by the dissolution of the stainless steel components of the work rack on which the plastic parts are suspended. Additionally, ferric ions are introduced by oxidation attack of the steel tanks through imperfections in the protective plastic coating which enter the solution and also by conventional rust present in the plating environment. Copper ions similarly are introduced through the water system including copper pipeline, the copper bus bars adjoining the treating receptacles, a dissolution of the rack splines as well as from carryover and bleed-out from the racks as a result of the presence of residual copper on the racks resulting from copper plating operations. Such residual contamination of the racks cannot be completely eliminated in spite of vigorous stripping of the racks at the conclusion of each plating cycle. In many instances, ferric and cupric ion contamination is also introduced as inherent impurities in the chemicals employed to make up the several solutions including the accelerator solution.
In any event, the presence of such ferric cupric, and hexavalent chromium ions in only relatively minimal amounts has adversely effected the accelerating treatment and heretofore has occasioned a discarding and replacement of the aqueous accelerating solution after only a short period of operation.
The present invention overcomes the problems and disadvantages associated with processes for the plating of plastic articles, and particularly the acceleration thereof, by providing a solution which is stable, which is easy to control, which is tolerant to such conventional metallic impurities present, which will further inhibit plating on the protective plastic rack coating, and which is of versatile use over a variety of conventional platable plastic materials.
SUMMARY OF THE INVENTION
The benefits and advantages of the present invention are achieved by a process in which a polymeric plastic substrate is treated to render it receptive to electroless plating and includes the steps of etching plastic substrate with an aqueous acid solution containing hexavalent chromium ions whereafter the etched substrate is rinsed one or a plurality of times. The resultant etched substrate is thereafter activated with an acidic tin-palladium complex and is rinsed. The activated plastic substrate thereafter is contacted with an improved accelerating solution containing an aqueous soluble compatible substituted alkylamine which is present in an amount effective to complex substantially all of any contaminating reducible metal ions present, such as cupric and ferric ions, to extract any residual tin constituents present on the surface of the activated substrate. Conventionally, the substituted alkyl amine can be present in an amount of about 0.001 to about 100 g/l with amounts of about 0.01 to about 10 g/l being preferred. The aqueous amine containing accelerating solution further contains ions of mineral acids and/or aqueous soluble alkali salts thereof in amounts up to 120 g/l, and may additionally include a reducing agent for reducing agent for reducing any hexavalent chromium present to the trivalent state and may also contain a surfactant to provide a more uniform surface reaction.
The process employed the accelerating solution can be performed from about room temperature up to about 160° F. with temperatures ranging from about 135° F. to about 150° F. being preferred. Time periods of about 30 seconds up to about 5 minutes are usually satisfactory which will vary depending upon the type of plastic substrate, the degree of activation thereof, the temperature of the activating solution and related variables. The activating solution is operated in the acidic range of pH 0 up to about neutral and preferably less than pH 1.
Additional benefits and advantages of the present invention will become apparent upon a reading of the detailed description of the preferred embodiments taken in conjunction with the accompanying examples.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The process of the present invention is applicable for use with any of the various platable plastic or polymeric plastics including acrylonitrile-butadiene-styrene (ABS), polyaryl ethers, polyphenylene oxide, nylon and the like. The polymeric plastic parts are usually subjected to a cleaning treatment to remove any surface contamination which may further include an organic solvent treatment, in some instances, to render the substrate hydrophilic during the subsequent chromic acid etching step. Usually the cleaning step is performed employing an aqueous alkali soak solution followed by contact in an organic solvent medium which may comprise either a single-phase system or an aqueous-organic solvent emulision. The clean part is thereafter thoroughly water rinsed and is next subjected to an etching treatment in an aqueous acid solution containing hexavalent chromium ions and acid, such as sulfuric acid, to effect an etching of the surface thereof. The specific concentration of the etching solution, the temperature, and the duration of treatment will vary depending upon the specific type of plastic substrate and the parameters of the etching step are, accordingly, dictated by procedures well known and practiced in the art.
Following the etching step, the etched polymeric substrate is subjected to one or more cold water rinses and may additionally include a neutralization step employing an aqueous solution containing a reducing agent to effect a reduction of any residual contaminating hexavalent chromium ions to the trivalent state. A typical neutralization treatment is described in U.S. Pat. No. 3,962,497, the teachings of which are incorporated herein by reference. Following neutralization, if employed, the substrate is again water rinsed and thereafter is subjected to an activation treatment employing an aqueous acid solution containing a tin-palladium complex of the various types well known in the art. A typical one-step activation treatment is described in U.S. Pat. No. 3,011,920 and U.S. Pat. No. 3,532,518, the substance of which is incorporated herein by reference.
Following the activation treatment, the activated polymeric substrate is subjected to one or a series of separate cold water rinse treatments whereafter it is subjected to acceleration in an aqueous solution in accordance with the practice of the present invention as more fully hereinafter to be described. Following acceleration, the part is cold water rinsed and thereafter is subjected to an electroless plating to apply a conductive continuous and adherent metallic plating such as copper, nickel, or cobalt over all or selected surface areas thereof. The electroless plating step is performed in accordance with well known and established practices employing an aqueous solution containing a reducing agent and a reducible salt of the metal to be deposited on the surface. Following the electroless plating step, the part is subjected to one or a plurality of water rinse treatments and is thereafter in condition for conventional electroplating employing normal procedures to apply one or a plurality of overlying plating on the polymeric substrate.
In order to achieve selective plating of only certain areas of polymeric plastic articles, it is conventional either prior to or following the cleaning step to apply a stop-off coating to those areas which are not to be plated. Any of the commercially available stop-off compositions can be employed for this purpose. The present invention also provides benefits in this regard by achieving proper acceleration of the plastic substrate to be plated while inhibiting or substantially completely eliminating plating on such stop-off areas.
The accelerating solution of the present invention comprises an aqueous solution containing as its essential constituents an aqueous soluble compatible substituted alkyl amine which may be present in an amount of 0.001 up to about 100 g/l, and preferably from about 0.01 to about 10 g/l. The substituted alkyl amine is further characterized as one which is compatible with the palladium constituent on the plastic surface as well as the polymeric material itself and which is effective to form complexes with any ferric and cupric ions present thereby reducing their oxidation potential and preventing oxidation of the palladium constituent on the substrate. The substituted alkyl amine further includes the alkali metal salts thereof as well as derivatives thereof. The term "alkali metal" is used herein in its broad sense to include ammonium as well as the alkali metals.
Typical of the substituted alkyl amines which are suitable for use in the practice of the present invention are:
Glycine;
[NH 2 CH 2 COOH]
Alanine;
[CH 3 CH(NH 2 )COOH]
Aspartic Acid;
[COOHCH 2 CH(NH 2 )COOH]
Glutamic Acid;
[COOH(CH 2 ) 2 CH(NH 2 )COOH]
Cystine;
[HOOCCH(NH 2 )CH 2 SSCH 2 CH(NH 2 )COOH]
Nitrilodiacetic Acid;
[HN(CH 2 COOH) 2 ]
Triethanolamine;
[N(CH 2 CH 2 OH) 3 ]
Nitrilotriacetic Acid;
[N(CH 2 COOH) 3 ]
N-Hydroxyethylenethylenediamenetetraacetic Acid, (HEDTA);
[HOOCCH 2 N(CH 2 CH 2 OH) (CH 2 ) 2 N(CH 2 COOH) 2 ]
Ethylenediaminetetraacetic Acid, (EDTA);
[(HOOCCH 2 ) 2 NCH 2 CH 2 N(CH 2 COOH) 2 ]
N,N,N',N'-Tetrakis (2-Hydroxypropyl) Ethylene Diamine;
[(CH 3 CHOHCH 2 ) 2 NCH 2 CH 2 N(CH 2 CHOHCH 3 ) 2 ]
Diethylenetriamine Pentaacetic Acid;
[(HOOCCH 2 ) 2 NCH 2 CH 2 N(CH 2 COOH)CH 2 CH 2 N(CH 2 COOH) 2 ]
Of the substituted alkyl amines suitable for use in the practice of the present process EDTA comprises the preferred material including the mono, di, tri and tetra alkali metal salts thereof.
The foregoing amines or classes of amines can be further categorized by the following general structural formula: ##STR1## Wherein:
R 1 is an organic radical ##STR2## in which x and y=1 to 4;
R, R 2 and R 3 is H or --CH 2 ] z X in which z=1 to 6 and X is --OH, --SO 3 H, --COOH, --NH 2 , halide, --CH 3 , or --OCH 3 ,
as well as the alkali metal salts of the foregoing.
The aqueous accelerating solution, in addition to the substituted alkyl amines, further includes, as an essential constituent, mineral acids and/or aqueous soluble salts thereof which are compatible with the other constituents of the accelerating solution as well as the plastic substrate. Included among the such mineral acids are acids such as halogen acids including hydrochloric, hydrobromic, hydrofluoric and fluoroboric of which hydrochloric constitutes the preferred acid. Additionally, acids such as sulfuric acid can also be employed as well as alkali metal bisulfates to introduce sulfate and bisulfate ions in the accelerating solution. Nitric acid and the alkali metal salts thereof and phosphoric based acids and the alkali metal salts thereof are also suitable for use. The presence of such anions further facilitates the extraction and solubilization of the residual tin compounds or constituents on the surfaces of the activated polymeric substrate. Typically, at least a portion of the halogen and sulfate anions can be introduced by way of salts such as sodium chloride, sodium sulfate, sodium bisulfate, and the like. Conventionally, the inclusion of such supplemental acid constituents can be made to provide a pH of the resultant accelerating solution ranging from 0 up to about neutral, and preferably a pH of less than 1. The total concentration of the acid anions is usually controlled within a range up to about 120 g/l, with concentrations of about 40 to about 90 g/1 being preferred. When fluoride and/or nitrate anions are employed, their total concentration in the solution should not exceed about 10 g/l because of their relatively high activity toward the plastic substrate.
In accordance with a further embodiment of the present invention, it is preferred to further incorporate a controlled effective amount of a reducing agent in the aqueous accelerating solution for the purpose of reducing any residual hexavalent chromium ions to the trivalent state. Suitable reducing agents include those which are compatible with the other accelerating solution constituents and include reducing sugars, hydrazine, oxalate, alkali metal hypophosphites, hydroxylamine salts, and the like. Of the foregoing, hydroxylamine salts of the type disclosed in U.S. Pat. No. 3,962,497 including hydroxylamine hydrochloride, [NH 2 OH.HCl], hydroxylammonium acid sulfate, [NH 2 OH.H 2 SO 4 ], hydroxylammonium sulfate, [(NH 2 OH) 2 .H 2 SO 4 ] and related compounds constitute the preferred reducing agent. Such reducing agents can usually be employed in amounts of about 0.005 up to about 10 g/l.
In accordance with a further preferred embodiment of the present invention, the aqueous acid solution can contain a controlled amount of a surfactant to increase uniformity of reaction with the substrate achieving a more uniform acceleration thereof. Surfactants suitable for use include any of those well known in the art which are compatible with the other bath constituents. Such surfactants, when employed, can be used in amounts up to about 5 g/l.
The accelerating solution can be employed at temperatures ranging from about room temperature (65° F.) to temperatures below boiling point of the solution. Ordinarily, the accelerating solution is contained in treating tanks incorporating a protective plastisol lining and for practical consideration, temperatures up to about 160° F. are employed to avoid any thermal degradation or decomposition of such protective linings. In accordance with a preferred practice, the aqueous accelerating solution is employed at temperatures ranging from about 135° F. up to about 150° F. which provides for reasonable treating times consistent with the available operating cycle time of the continuous plating system.
The aqueous accelerating solution can be applied to the activated plastic substrate by any one of a variety of techniques of which immersing the plastic parts in the solution constitutes a preferred practice. Generally, immersion times from about 15 seconds up to about 30 minutes can be employed while time periods ranging from about 30 seconds up to about 5 minutes employing solutions at a temperature of about 135° F. to about 150° F. are satisfactory for most plastic materials and part configurations. The specific time period will vary somewhat depending upon the nature of the plastic material, the degree of activation of the polymeric substrates and the temperature of the solution. Typically, for ABS type plastics, accelerating treatments of from about 30 seconds to about 90 seconds at temperatures of 135° to about 150° F. are satisfactory.
In order to further illustrate the process of the present invention, the following examples are provided. It will be understood that these examples are provided for illustrative purposes and are not intended to be limiting of the scope of the invention as herein described and as set forth in the subjoined claims.
EXAMPLE 1
A series of test panels of a nominal size of about 3 inches by about 4 inches by 1/10th inch thick comprised of a platable ABS plastic are subjected to a pretreatment and electroless plating as hereinafter described. One set of such panels is comprised of a ABS plastic commercially available under the designation PG 298 from Monsanto Chemical while another ABS plastic was employed commercially available under the designation EP-3510 Marbon Cycolac from Borg-Warner Chemicals. In addition, test parts comprised of a modified polyphenylene oxide resin were also processed. The polyphenylene oxide resin is commercially available under the designation Noryl TN-235 from General Electric Company.
After appropriate cleaning, the plastic panels and parts are etched in an aqueous acid solution containing 356 g/l chromic acid, 412 g/l sulfuric acid and 0.2 g/1 of a perfluorinated proprietory wetting agent commercially available under the designation FC-98 from Minnesota Mining and Manufacturing Company. The parts and panels were immersed for a period of five minutes in the aqueous etching solution maintaining at 160° F. while undergoing an air agitation. At the conclusion of the etching treatment, the parts and panels were removed and cold water rinsed with tap water for a period of 30 seconds. The rinsed parts are thereafter neutralized in an aqueous solution containing 18 g/l hydrochloric acid, 3 g/l hydroxyl amine sulfate. The neutralization treatment is carried out for one minute with air agitation at a solution temperature of about 100° F.
After neutralization the panels and parts are cold water rinsed and are subjected to an activation treatment in an aqueous acid solution containing 0.77 g/1 palladium, 9 g/l tin chloride, 35.2 g/l hydrochloric acid and 192 g/l sodium chloride. An activation treatment of about 3 minutes at a solution temperature of 90° F. is employed. Thereafter the parts are cold water rinsed with tap water and are subjected to an accelerating solution hereinafter described.
After acceleration the parts are again cold water rinsed and subjected to an electroless plating step to apply a nickel plate thereover employing an aqueous bath containing 12 g/l nickel chloride hexahydrate [NiCl 2 .6H 2 O], 18 g/l of sodium hypophosphite [NaH 2 PO 2 .H 2 O], and 9 g/l citric acid. The electroless plating is performed at about 85° F. for a period of about 5 minutes. The electroless plated parts are extracted from the solution, are cold water rinsed and thereafter are inspected to examine the nature of the electroless plating obtained.
In accordance with the present example, the aqueous acceleration solution employed is formulated by dissolving 1 gram of the tetra sodium salt of ethylene diamine tetra-acetic acid in one liter of de-ionized water together with 45 g/l sulfuric acid, 40 g/l sodium chloride and 1 g/l hydroxyl ammonium sulfate. The plastic parts and test panels are immersed in this accelerating solution for a period of one and one half minutes at a temperature of 130° F. in the presence of air agitation.
The resultant nickel electroless plated parts and panels produced as hereinabove set forth are inspected and are observed to contain a lustrous, uniform metal deposit.
EXAMPLE 2
ABS test panels and parts comprised of the modified polyphenylene oxide polymer as described in example 1 are accelerated in an aqueous acid accelerating solution containing 30 g/l sulfuric acid, 15 g/l of sodium chloride and N,N,N',N'-Tetrakis (2-hydroxy propyl)-ethylene diamine. The activated and water rinsed plastic panels and parts are immersed in this accelerator solution for 1.5 minutes at 130° F. in the presence of air or mechanical agitation. The resultant parts and panels at the completion of the nickel electroless plating step are observed to contain lustrous, uniform metallic nickel deposits.
By employing de-ionized water for preparing the accelerator solution, no contaminating ferric or cupric ions are present. It was observed that similar good electroless nickel deposits are obtained employing such solution without incorporating the substituted alkyl amine. However, by an addition of 20 mg/l of trivalent iron introduced by way of ferric chloride to the solution, the nickel electroless plating coverage is reduced by approximately 90%. In contrast, when an equivalent 20 mg/l of trivalent iron is introduced in the accelerator solution containing the substituted alkyl amine, the electroless nickel plating coverage is only reduced by about 10%.
EXAMPLE 3
The same plastic panels and parts as described in Example 1 were processed in accordance with the sequence described in Example 1 with the exception that an accelerator solution is employed containing 30 g/l sulfuric acid, 15 g/l sodium chloride and 2 g/l of the tetra-sodium salt of ethylene diamine tetra-acetic acid (EDTA). The plastic test panels and parts are immersed in this accelerator solution for time periods of 30 seconds up to 30 minutes at temperatures varying from 70° up to 150° F. In all cases, lustrous, uniform metallic nickel deposits are rapidly formed during the subsequent electroless plating step.
The aqueous accelerating solution is further modified by the addition of 200 mg/l of cupric ions introduced by way of copper chloride and 10 mg/l of ferric ions introduced by way of ferric chloride. Satisfactory electroless nickel plating are again obtained and it is observed that no rack plating occurred on the plastisol protective rack coating during the electroless plating operations.
Another aqueous accelerator solution is prepared as before but omitting the substituted alkyl amine. Processing of test panels and plastic parts through the sequence as described in Example 1 results in a 50% to a 100% rack plating during the subsequent nickel electroless plating step. The further addition of 200 mg/l per liter of cupric ions and 10 mg/l of ferric ions to the accelerator solution devoid of the substituted alkyl amine resulted in substantially no nickel deposits on the test panels and parts.
EXAMPLE 4
A fourth series of test panels and plastic parts are processed through the sequence as described in Example 1 with the exception that an aqueous accelerator solution is employed containing 40 g/l sulfuric acid, 15 g/l sodium chloride and 10 g/l glycine. During the accelerating step, the test panels and plastic parts are immersed for a period of 90 seconds at 130° F. The panels and parts at the completion of the electroless plating step are observed to contain lustrous, uniform metallic nickel deposits. The addition of 20 mg/l of ferric ions to the accelerator solution did not significantly affect the quality of the electroless nickel deposits obtained. However, the addition of an equivalent quantity of ferric ions to the accelerator solution of this example devoid of the glycine additive resulted in little or no metallic nickel plating at all on the test panels and parts at the conclusion of the electroless plating step.
EXAMPLE 5
A fifth series of test panels and plastic parts are processed through the sequence as described in Example 1 with the exception that an aqueous accelerator solution is employed containing 50 g/l sodium bisulfate, 58 g/l sodium chloride and 0.016 g/l of the tetra-sodium salt of EDTA.
The acceleration step is performed employing the foregoing accelerating solution for a period of 90 seconds at a temperature of 130° F. Lustrous, uniform nickel metal deposits are obtained during the subsequent electroless nickel plating step.
The foregoing excellent results are obtained in spite of the fact that the commercial grade of sodium bisulfate employed incorporated 0.0276% by weight iron as a normal contaminant. Accordingly, the accelerating solution contained 13.8 mg/l of ferric ions.
A similar accelerating solution is prepared but without the addition of the substituted alkyl amine. In this instance, the resultant test panels and plastic parts at the conclusion of the electroless plating step are observed to incorporate dark deposits of low metal integrity and plate coverage of only about 85% of the plastic surface is obtained. By the addition of 5 mg/l of cupric ions to this same solution, the plating coverage was further reduced to only 70%. The addition of 10 mg/l of cupric ions caused a further reduction in nickel plating coverage to only 10% of the surface of the panels and parts. The further addition of cupric ions to provide a final concentration of 20 mg/l resulted in a nickel plating coverage of substantially zero. However, by the addition of 1 g/l of the tetra-sodium salt of EDTA to this solution containing 20 mg/l of cupric ions and the 13.8 mg/l of ferric ions resulted in an immediate restoration of the electroless nickel deposits providing for coverages of at least about 98% to 100% of the plastic surfaces.
While it will be apparent that the invention herein disclosed is well calculated to achieve the benefits and advantages as hereinabove set forth, it will be appreciated that the invention is susceptible to modification, variation and change without departing from the spirit thereof. | A process for treating a polymeric plastic substrate to render it receptive to electroless plating including the steps of etching the substate, rinsing and activating the etched substrate with an acidic tin-palladium complex, rinsing and thereafter accelerating the activated substrate employing an improved aqueous accelerating solution containing an aqueous soluble compatible substituted alkyl amine. The improved accelerating solution is stable, easy to control, tolerant to metallic impurities present in the solution, inhibits rack plating and is of versatile use. | 2 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a portable shelter whose frame members expand and contract between maximum and minimum dimensions. This movement permits selectively applying various sized shelter skins to a single frame and provides flexible resistance to the forces of the wind against the portable shelter skin. Such structure also provides a means for tensioning the shelter skin to keep the skin taunt against the frame when wind forces are not present.
2. Description of the Prior Art
Portable shelters are well known in the art and include various structures from simple pup tents to larger and more complex shelters, for example circus tents. These portable shelters are constructed using frames that are generally rigid in the belief that rigidity is necessary to resist the forces of the wind against the shelter skin. Adjustability built into most portable shelters is primarily to ease assembly and to provide some limited stretching of the shelter skin. In many cases, the shelter skin extends from the shelter poles without structural support, being simply stretched as taunt as possible in order to maintain the interior space. Without structural support the shelter skin flaps and moves with the wind creating a collapsing and expanding interior space frequently to the discomfort of those occupying the shelter. In addition, strong winds striking shelters supported by rigid frames such as that disclosed by U.S. Pat. No. 2,897,831 issued to O. G. A. Liden, meet such resistance and lack of flexibility that the structures may collapse.
The current art requires that when portable shelters of different sizes are needed a new shelter must be obtained, including a new frame and a new skin. Another problem with proper fit occurs when shelter skins shrink in some areas and stretch in others so that they no longer properly fit frames that have fixed dimensions.
Notwithstanding the existence of such prior art, it remains clear that there is a need for a portable shelter having a frame that provides full support for a shelter skin in order to maintain the interior space and yet provides flexibility so that the portable shelter can flex and give in strong winds. There is a need for a portable shelter having a frame that provides structure for tightening the skin in relation to the frame to reduce the amount of flapping of the skin and to reduce sagging of the skin into the interior space. There is also a need for a frame that may be enlarged by extending the existing members of the frame or by adding new members, which only requires the purchase and storage of a larger skin.
SUMMARY OF THE INVENTION
The present invention relates to a portable shelter that has a frame that is flexible, expandable, and has structure for tensioning the shelter skin. The shelter frame fully supports the shelter skin so that the interior space is maintained. The shelter frame comprises a plurality of posts each having a first end and a second end. The first end of each post is connected to the first ends of the other posts and the second end of each post engages a support surface. A plurality of attaching means connects at least one of the posts to the support surface.
Each post comprises a rafter member having a first end and a second end, the first end including the first end of the post, and a leg member having a first end and a second end, whose second end includes the second end of the post. The second end of the rafter member is attached to the first end of the leg member to form a hip portion. Each rafter member comprises a first portion and a second portion with the second portion slideably engaging the first portion so that the rafter member is extendable between an extended position and a shortened position.
In a first embodiment the posts are connected to one another by being attached to a ridge pole. The ridge pole is comprised of at least one section which includes a first part and a second part. The second part of the section slideably engages the first part so that the ridge pole is extendable between an expanded position and a retracted position.
A lifting means is attached to the ridge pole and applies a lifting force thereto. The lifting force is angularly applied creating vertical and horizontal components of that force, the vertical component lifting the rafter and the horizontal component pulling the rafter ends longitudinally outwardly.
In another embodiment, the first ends of the posts are connected to one another by the skin of the shelter. In this embodiment, the lifting means is attached to the first end of at least one post.
The invention accordingly comprises an article of manufacture possessing the features, properties, and the relation of elements which will be exemplified in the article hereinafter described, and the scope of the invention will be indicated in the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
For a full understanding of the nature and objects of the invention, reference should be had to the following detailed description taken in connection with the accompanying drawings, in which:
FIG. 1 is a side elevational view of the portable shelter frame of this invention illustrating the shelter skin mounted thereon, a portion of which is broken away to better view the shelter frame.
FIG. 2 is an end view of a pair of posts of the invention of FIG. 1 with one of the posts broken away and illustrating the shelter skin attached thereto.
FIG. 3 is a perspective detailed view of a leg tensioning means of FIG. 2 illustrating the shelter skin attached thereto.
FIG. 4 is a detailed view of the ridge pole of FIG. 2.
FIG. 5 is a detailed sectional view of the rafter of FIG. 2 illustrating the means for extending the rafter.
FIG. 6 is a detailed sectional view of the hip portion of the invention of FIG. 2 illustrating a means for tensioning the skin attached thereto.
FIG. 7 is a detailed sectional view of the leg tensioning means of FIG. 2.
FIG. 8 is a detailed sectional view of the ridge pole of FIG. 1 with portions broken away for convenience.
FIG. 9 is a side elevational view of a second embodiment of the invention of FIG. 1.
FIG. 10 is a side elevational of a third embodiment of the invention of FIG. 1.
Similar reference characters refer to similar parts throughout the several views of the drawings. Different embodiments utilize reference numbers increased in increments of 100 for identification of similar parts.
DETAILED DESCRIPTION
A preferred embodiment for the portable shelter of this invention is illustrated in the drawing FIGS. 1-8 and is generally indicated as 1. The portable shelter 1 comprises a frame 10 and a skin 11 that is mounted thereon. The frame is includes a ridge pole 12 that has a first end 14 and a second end 16. The ridge pole comprises at least one section 18; however, in the embodiment illustrated in FIG. 1 the ridge pole 12 comprises two sections 18. Each section 18 comprises a first part 20 and a second part 22 that extend between two pair of posts as discussed further below. As best seen in FIG. 8, the first part 20 has a first end 24 and a second end 26 and the second part 22 has a first end 28 and a second end 30. The ridge pole 12 has a bore 32 therethrough that extends from the first end 14 to the second end 16. In a preferred embodiment illustrated in FIG. 1, the bore 32 proximal the first end 28 of the second part 22 is enlarged to form an enlarged portion 33 that is sized to receive the second end 26 of first part 20. The first end 26 is allowed to freely move inwardly and outwardly within the enlarged bore 33 of the second part 22 extending the ridge pole 12 between a fully expanded position and a retracted position. The fully expanded position is defined as the position of the ridge pole 12 just before the first end 26 of the first part 20 disengages from the enlarged portion 33 of the second part 22 in each section 18. The fully retracted position is defined as the position of the ridge pole 12 when the first end 26 engages the stop 34 in each section 18.
The length of the enlarged portion 33 is based upon the desired expansion for a particular sized shelter. For example, a 12 foot by 16 foot shelter frame 10 having two sections 18, is preferably sized to extend to a 14 foot by 20 foot shelter. Thus, each enlarged portion 33 of the second part 22 extends 21/2 feet so that it can receive approximately 21/2 feet of first part 20 in the retracted position. The ridge pole 12, in the retracted position, is approximately 16 feet long and when each section 18 is moved to the expanded position the ridge pole 12 extends to at least 20 feet. This is but one configuration, many other sizes of portable shelters 1 with predetermined expansion capability may be made using the teachings of this invention.
The ridge pole 12 of the shelter frame 10 may be comprised of a plurality of sections to create a shelter 1 of greater overall length. Each section 18 may comprise a first part 20 and a second part 22 which slidably engage one another for extension of that section 18. Other configurations may comprise sections 18 that are not extendable, that is sections 18 that do not have first and second parts 20 and 22 respectively. In the preferred embodiment illustrated in FIG. 1, two sections are provided and each section 18 is comprised of extendable parts 20 and 22.
A lifting means 35 is attached to the ridge pole 12 to provide a lifting force in support of the ridge pole 12. The lifting means 35 comprises joining means, conveniently eye bolts 36a and b with nuts 37a (not shown) and 37b respectively threaded thereto, and a plurality of first, second, third, and fourth lines, 38a, 38b, 38c, and 38d, respectively attach the eye bolts 36a, 36b, and 36c to a support means, conveniently trees 40, as shown in FIG. 1. Line 38a at one end is connected to eye bolt 36a and at the other end is connected to a portion of the tree 40a that lies in a horizontal plane above the ridge pole so that an upward force is applied to the ridge pole by the line 38a. Line 38a extends upwardly and outwardly, in relation to the frame 10, at an angle less than 90 degrees; therefore, the force comprises vertical and lateral components that are each applied to the ridge pole 12. One end of line 38b is connected to the eye bolt 36b and the other end is attached to a tree 40b to also apply a lifting force to the ridge pole 12 that has both vertical and lateral components extending outwardly from the shelter 1. One end of a third line 38c is attached to eye bolt 36a and the other end extends through the bore 32 of the ridge pole 12 and is attached to eye bolt 36b. A ring 42a is placed on line 38c adjacent to the eye bolt 36a and line 38a is attached to the ring 42a. Similarly, at the other end of the ridge pole 12, a ring 42b is placed about the line 38c adjacent the eye bolt 36b so that the line 38b may be attached thereto and thus be connected to eye bolt 36b. The rings 42a and 42b permit movement of the ridge pole 12 along line 38c, particularly during the expansion and contraction movement of the ridge pole 12. To provide additional lifting support to the ridge pole 12, a linking means, conveniently eye bolt 36c, is attached to the ridge pole 12 intermediate the first end 14 and second end 16 of the ridge pole 12, preferably to the center of the ridge pole 12 between the two sections 18. A fourth line 38d extends from a point on tree 40a, that is above the ridge pole 12 through eye bolt 36c to a point in the second tree 40b, which is also above the ridge pole 12. As can be seen in FIG. 1, lines 38a, 38b, and 38d may be a single line which extends from the ring 42a to the tree 40a through the eye bolt 36c to the tree 40b and to the ring 42b or they may be individual lines tied individually to the trees 40. In the embodiment illustrated in FIG. 1, two trees 40 that are spaced apart from one another comprise the support means; however, any convenient support means may be used, including but not limited to a single large tree, a pair of poles that extend above the shelter frame 10 or large vehicles parked adjacent to the shelter frame 10.
A plurality of posts 44 each have a first end 46 that is connected to the ridge pole 12 and a second end 48 that engages a support surface 50, which in FIG. 1 is illustrated as being the surface of the ground. In a preferred embodiment as illustrated in FIG. 1, the posts 44 are attached to one another in opposing pairs at the end of each section 18 and between the sections 18. The shelter frame 10 may be erected on wooden platforms, concrete slabs or any other convenient surface. As illustrated in FIG. 2, each post 44 is comprised of a rafter member 52, having a first end coinciding with the first end 46 of the post 44 and a second end 54. Each post 44 further comprises a leg member 56 having a first end 58 and a second end that coincides with the second end 48 of the post 44. The first end 58 of the leg 56 is attached to the second end 54 of the rafter 52 to form a hip portion 60 where the rafter member 52 forms an angle with the leg member 56. Each rafter member 52 is comprised of a first rafter portion 62 and a second rafter portion 64 that slidably engages the first rafter portion 62 so that the rafter member 52 is extendable between an extended position and a shortened position. In the embodiment disclosed in FIG. 1 and FIG. 2, the first end 66 of the first rafter portion 62 has a bore 68 therein which is sized to receive the first end 70 of the second rafter portion 64. As seen in the detail in FIG. 5, the second rafter portion 64 has an elongated aperture 72 therethrough that has a first end 74 and a second end 76. The first rafter portion 62 has a port 78 therethrough which is aligned with aperture 72 when the second rafter portion 64 is inserted in the bore 68 of the first rafter portion 62. A rafter eye bolt 36d is inserted through the port 78 and the aperture 72 and is attached loosely to the rafter member 52 by nut 37d. Pulling on the second rafter portion 64 extends the rafter member 52 until the rafter eye bolt 36d engages the second end 76 of the aperture 72, which is defined as the extended position. When the second rafter portion 64 is pushed inwardly into the first rafter portion 62, the second end 74 of the aperture engages the rafter eye bolt 36d, which defines the shortened position. Additional ports, for example port 78b may be provided through the second rafter portion 62 to increase the maximum length of the rafter member 52.
The length of the bore 68, as in the ridge pole 12, is determined by the desired expansion needed to create a particular sized shelter 1. For example, a 12 foot by 16 foot shelter is preferably sized to extend to a 14 foot by 20 foot shelter. Thus, each rafter must be extendable for more than 1 foot (due to the angle of the rafters) to enable the shelter to be extended from 12 to 14 feet. Therefore, the bore is generally two (2) feet in length so that it can receive approximately two (2) feet of the first end 70 of the second rafter portion 64 in the shortened position (12 foot wide). A pair of posts 44 extend across the support surface 50 approximately twelve (12) feet in the shortened position, and approximately fourteen (14) feet when each rafter member 52 is moved to the extended position. As mentioned previously, this is but one configuration as many other sizes of portable shelters 1 with predetermined expansion capability may be made using the teachings of this invention.
As seen in FIG. 1 and FIG. 2, the portable shelter frame comprises a plurality of tensioning means 80 with at least one of the tensioning means slidably attached to at least one of the posts 44. In the embodiment disclosed in FIG. 1 and FIG. 2, it can be seen that two tensioning means 80 are attached to each post 44. One of the tensioning means 80 is attached to leg member 56 intermediate the first end 58 and the second end 48 and a second tensioning means 80 is attached adjacent the hip portion 60. As best seen in FIG. 7, the tensioning means 80 on the leg member 56 comprises a sleeve 82 having a hole 84 therethrough which is aligned with a slot 86 that is formed through the leg member 56 so that a sleeve eye bolt 36e may be inserted through the hole 84 and the slot 86 and be attached firmly to the sleeve 82 by nut 37e. The sleeve 82 is free to slide upon the leg member 56 until the sleeve eye bolt 36e engages one end of the slot 88, defining the first position, or engages the other end of the slot 90 defining the second foot position. The slot 86 in a preferred embodiment, for a 12×18 shelter 1, is generally three (3) inches long; however any length suitable for the size of shelter 1 may be used.
FIG. 6 illustrates a tensioning means 80 attached adjacent to the hip 60 which is configured identically with the tensioning means that is attached to the leg as illustrated in FIGS. 7 with one exception. The sleeve 82 is curved so that it may slide upon the curved hip portion 60. In a preferred embodiment, the curvature is approximately 60 degrees; however, since any reasonable curvature may be used to form the hip portion 60 a sleeve only need to approximately match that curvature so that it will freely slide upon the hip portion 60 of the post 44.
A plurality of attaching means 92 are used to attach the posts 44 to the support surface 50. In the embodiment disclosed in FIG. 1 in which the support surface 50 comprises the earth, the attaching means comprises a stake 94 with a cord 96 that is attached to the stake 94 at one end and to a sleeve eye bolt 36e at the other end.
The frame 10 for a shelter 1 may be provided to fit existing shelter skins or an appropriately sized skin 11 may be provided with the particular frame offered. The shelter skin 11 may be made of any suitable water resistant or water proof material well known in the art. The skin is prepared as shown in FIG. 4, with holes 97 through the skin 11 to receive all the eye bolts 36 therethrough. Each hole 97 is placed in the skin 11 so that the sleeve eye bolt 36e are generally at the mid point of the slots 86 of the tensioning means 80 when the skin 11 is generally taunt and at the appropriate points to receive the rafter eye bolts 36d in the rafters 52 and the eye bolts 36a-c in the ridge pole 12, which depends largely upon the size of the skin being used.
FIG. 9 discloses a second embodiment 100 of the invention of FIG. 1, in which the line 138c is not utilized. The skin 111 limits the expansion of the ridge pole 112.
FIG. 10 discloses a third embodiment 200 of the portable shelter which comprises at least two pair of posts 244. Each post 244 having a first end 246 and a second end 248. The first ends 246 of each pair of posts are attached to one another and the second ends 248 engage the support surface 250. In this embodiment there is no ridge pole 212, but the remainder of the structure of each post 244 is the same as the structure in the other embodiments of the invention. Each pair posts 44 are spaced apart from the other pairs of posts 44. Without the ridge pole 212 the pairs of posts 44 are held in place by the attaching means 292 and the skin 211 when mounted thereon. Additionally, there is no line 238c as the lines 238b and 238a are attached directly to the eye bolts 236b and 236a, respectively, which are attached to the first ends 246 of the posts 244.
The portable shelter frame in each of the preferred embodiments disclosed is comprised of Poly Vinyl Chloride (PVC) piping which is selected to support a particular sized portable shelter. For example, a 12 by 16 portable shelter 1 having three pairs of posts 44 as disclosed in FIG. 1 will be constructed of schedule 40 PVC piping having an outside diameter of approximately 1 and 1/40 inches and a thickness of approximately 3/16ths of an inch. Of course, any other material suitable for the purpose may be substituted for PVC, including but not limited to aluminum, wood, steel, or any other suitable synthetic resin. When using PVC plastic piping material standard fittings that are well known in the art are used to connect the various parts of the portable shelters 1, 100, and 200. When using other materials connectors suitable for that purpose that are well known in the art are used to make the connections, including but not limited to, providing sleeving with bolted connections or other disassembleable attaching means for easy assembly and disassembly. The PVC piping is held in the fittings by a friction fit so that the frame 10 may easily be disassembled for portability and storage.
Having thus set forth a preferred construction for the portable shelter 1 of this invention, it is to be remembered that this is but a preferred embodiment. Attention is now invited to a description of the use of the portable shelter 100 and 200.
As mentioned previously the assembly of the portable shelter 1 requires adjacent structures to which a line may be attached to provide a lifting force to the upper portion of the shelter 1. When in the woods, trees may be easily located which are sufficiently spaced apart to provide the necessary support; however, when the portable shelter 1 must be assembled in an area without trees separate posts, not shown, are used to provide the necessary support similar to that provided by a tree. Once a suitable site is located a ridge pole is stretched upon the ground to fit the size of skin 11 being used. The skin 11 is then placed over the ridge pole 12 so that the eye bolts 36a, 36b, and 36c may be passed through a washer 98, the skin 11 and the ridge pole 12 with a nut 37 being attached to the bolt to hold the skin 11 to the ridge pole 12. Line 38c is inserted through bore 32 and then attached at one end to eye bolt 36a and at the other end to eye bolt 36b with rings 42a and 42b located proximal to the respective eye bolts 36a and 36b. Lines 38a and 38b are then attached to the respective rings 42a and 42b with the other ends of the lines being attached to a point in a tree that will be above the expected height of the shelter 1. The first end 46 of each rafter 52 is then attached to the ridge pole 12. The skin 11 is then stretched over the rafter members 52 and attached thereto by the rafter eye bolts 36d and the sleeve eye bolts 36e of the tensioning means at the hip portion 60. Lines 38a and 38b are then shortened raising the ridge pole and rafters above the support surface 50 so that the remaining portion of the legs 56 may be easily attached to the legs and rafters by the coupling 99. Once the legs 56 are in place the lines 23a and 23b are again tightened applying a lifting force so that the ridge pole 12 is longitudinally stretched to match the length of the ridge of the skin 11 removing wrinkles from the skin 11. In addition, line 38b is tightened to reduce any sag in the middle of the ridge pole. The vertical element of the lifting force extends the rafters from the shortened position toward the extended position as necessary to remove wrinkles in the skin 11.
The attaching means 92, in the embodiment disclosed in FIG. 1, comprises a stake 94 and cord 96 which are attached individually to each tensioning means 80. As the cord 96 is tightened the sleeve eye bolts 36e move downwardly along the slot 86 stretching the skin 11 between rafter eye bolt 36d and sleeve eye bolt 36e at the hip 60 and between the tensioning means 80 at the hip 60 and the tensioning means on the leg 56. The bottom of the skin is then tightened by staking (not shown) or by placing the skin under the ends 48 of the legs 56 and attaching them to a ground cloth (not shown).
The portable shelter is now assembled with the skin 11 stretched smoothly over the frame 10. Assembled in this manner, when the wind blows the ridge pole 12 will give inwardly as the first part 20 slides inwardly into the second part 22. In addition, the ridge pole will slide upon line 38d on eye bolt 36c providing additional increasing resistance through the wind as the eye bolt 36c moves up the line 38d. When the wind subsides the frame 10 returns to its original position. As the skin 11 is tauntly applied to the frame 10, little flapping of the skin 11 occurs, providing a stable and clear area on the interior of the portable shelter 1.
Now that the invention has been described, | A portable shelter having a frame whose members freely move between a maximum and a minimum dimension to enable selectively applying various sized shelter skins to the frame and to tauntly stretch the shelter skin thereon. The skin also comprises slidable tensioning means that stretch the skin over a portion of the frame. The upper portion of the shelter is partially supported by a lifting force applied thereto. | 4 |
BACKGROUND AND SUMMARY OF THE INVENTION
The present invention relates to a new variety of sweet cherry tree which bears medium to large, firm, attractive fruits of excellent quality and flavor.
This new variety was developed at the Washington State University's Irrigated Agriculture Research and Extension Center (I.A.R.E.C.) at Prosser, Washington. It was selected from among fourteen (14) seedlings of the variety Stella (unpatented variety)×unknown and was tested as PC 7222-1. Second generation test trees were planted on the Roza Unit of the Center in the spring of 1979 and came into production in 1983.
The new sweet cherry variety ripens 5-6 days before Bing (popular unpatented commercial variety). It is self-fertile, blooms 2-3 days before Bing and is pollen compatible with Bing.
The new cherry variety resembles Bing in shape and appearance. The trees have been consistently productive, bearing fruits comparable in size and as firm as Bing. The fruits are Bing-shaped, glossy and attractive when mature and possess good cracking tolerance.
Fruit stems are medium length, similar to those of Bing. Fruit shape is broadly cordate and the flesh, which colors slowly, is light to medium red.
Fruit buds of PC 7222-1 have greater winter hardiness than Bing as demonstrated by winter freezes at the test site near Prosser in December 1990 and February 1996.
The tree is vigorous and spreading in shape and has proven to be a very precocious and fruitful bearer of early to mid-season high quality cherries.
Soluble solids are equal to or slightly more than Bing when comparing fruits of equal maturity and fruit kept in cold storage at 33°-34° F. for four weeks stored equal to Bing fruits.
The seeds are semi-freestone and small. All second and third generation test trees observed closely have shown no tendency toward the "Cherry Crinkle-leaf" genetic disorder which is common in Bing, as well as in several other varieties of sweet cherry.
Interest in this new variety is for a firm, high quality shipping variety for the early season market. The present new variety fills the gap between the early maturing Chelan variety (U.S. Plant Pat. No. 8545) and the popular commercially grown Bing variety. The present variety fits into this gap period very well, maturing about five days after Chelan and about 5-6 days ahead of Bing.
Trees of the subject variety are vigorous and, following several years of testing, have proven compatible with all common rootstocks used under sweet cherry trees.
Asexual reproduction of this new and distinct variety shows that its desirable characteristics come true to form and are established and transmitted through succeeding propagations by grafting at the test facilities near Prosser.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
In the accompanying photographs, vegetative growth, fruit and seeds are shown in color as nearly true as is reasonably possible to make in color photographs of this nature.
FIG. 1 shows and compares the maturity of fruit picked from trees of the subject variety, PC 7144-3 (unnamed), PC 7146-23 (Chelan) and Bing. The trees were planted in adjacent rows in a test orchard near Wapato, Wash.
FIG. 2 compares size and shape of mature PC 7222-1 and Bing fruits.
FIG. 3 shows size of mature PC 7222-1 fruits (all cherries pictured are 10 row or larger).
FIG. 4 shows PC 7222-1 fruits with seeds exposed and light-red flesh color.
FIG. 5 shows current-season vegetative growth and leaves of the subject variety.
DETAILED DESCRIPTION OF THE INVENTION
Following is a detailed description of the new variety of cherry tree with color terminology in accordance with the Munsell Color Cascade chart except where general color terms of ordinary dictionary significance are used.
Tree:
Size.--Large.
Vigor.--Vigorous.
Branching habit.--Upright-spreading.
Density.--Average for sweet cherry.
Form.--Round-headed when mature.
Hardiness.--Hardy in area where tested (lower Yakima Valley of Washington).
Production.--Very productive.
Bearing.--Consistent, regular.
Trunk.--Size: Stocky. Bark texture: Typical for sweet cherry. Bark color: Grey-brown (26-13). Lenticels: Numerous, medium 3.2-5.4 mm in diameter, brown.
Branch.--Size: Stocky. Texture: Average, typical for sweet cherry. Color: First year wood: greenish-brown (32-10); second year wood: grey-brown (24-12). Lenticels: Numerous, small, 1.5-2.1 mm in diameter, brown.
Leaves.--Measurements are from mature leaves attached at midpoint of actively growing upright shoots of current season's growth. Size: Large, 16-17 cm long, 8.5-9 cm wide. Form: Lanceolate with acuminate tip. Color: Upper surface: glossy-green (20-12), lower surface: light-green (17-10). Midvein: Medium, light-red (40-11), 1.5 mm in diameter. Petiole: Medium, 4.5 cm long, thick 2.3 mm, light-green to pink with darker red tinge along petiole groove. Texture: Smooth. Margin: Crenate to finely serrate. Glands: Variable in number but mostly two, compressed, positioned both alternate and irregular, medium, oval to reniform shape, shiny with slightly reddish center when immature, darker red (38-12) when mature, glabrous, positioned on rim of petiole groove 4-7 mm from base of leaf petiole. Stipules: Small, usually two 1.2-1.8 cm in length, light-green (18-8).
Flower buds.--Hardiness: Hardy. Size: Medium. Length: Medium. Form: Plump, conic, free.
Flowers.--Self-fertile. First bloom: April 5 at Prosser test site (10-year average), early when compared with other varieties. Full bloom: April 12 at Prosser test site. Size: Medium large, 24-30 mm in diameter when fully open. Color: White. Bloom count: Abundant, 5-8 per spur cluster. Petals: Average, 18-20 mm in length and 14-15 mm in width, obovate, cupped slightly inward, white. Nectaries: Light-green when mature (22-7). Anthers: Large, yellow (27-4). Pollen: Abundant, yellow (27-6). Pedicel: Medium length 13-15 mm, light-green (23-6).
Fruit.--Maturity: Eating ripe June 11 at Prosser test site (9 year average). Date of first picking: June 11 at Prosser. Date of last picking: June 19 at Prosser. Size: Large, 9.1-9.5 grams, diameter transversely across suture 2.7-2.9 cm, diameter apically 2.4-2.5 cm. Form: Uniform, symmetrical, broadly cordate, rounded apex end. Suture: Very shallow, very slight darker mahogany-colored line extends from base to apex. Stem cavity: Broad, rounded shoulders, shallow. Base: Rounded. Apex: Rounded, pistil point apical and distinctive with very small white dot. Stem: Medium thick, variable 3.5-3.9 cm in length, light-green (21-8). Skin: Thickness: Medium. Texture: Medium. Tenacity: Tenacious to flesh. Tendency to crack: Susceptible to cracking caused by prolonged rains but more tolerant than Bing, none in dry season. Down: Wanting. Color: Mahogany-red (41-15). Flesh: Color: Red (39-9). Surface of pit cavity: Red (38-11). Texture: Very firm, crisp. Fibers: Few, cream color, fine. Ripens: Very evenly. Flavor: Sweet, low acid. Juice: Light-red (39-8). Aroma: Slight. Eating quality: Very good.
Stone.--Type: Semi-free. Size: Small, 1.2-1.3 cm long, 0.9 cm wide. Form: Oval with small protruding wing along basal shoulder of ventral suture. Base: Rounded. Helium: Small, oval to slightly oblong. Apex: Rounded. Sides: Equal. Surface: Smooth. Ventral edge: Narrow suture subtended by two low ridges converging basally and apically. Dorsal edge: Narrow, smooth, narrow ridge from base to apex. Color: Tannish-white when dry. Tendency to split: None.
Use: Early season shipping, fresh market.
Keeping quality: Good.
Resistance to insects and diseases: Susceptible to Bacterial Canker (Pseudomonas), no Cherry Crinkle-leaf noted.
Shipping quality: Firm, excellent, at least as good as Bing.
Variance in botanical details: The cherry tree and its fruit herein described will vary due to climatic, soil and growing conditions under which it may be grown. The present description being of the variety as grown in the Lower Yakima Valley of Washington. Comparisons to the Bing variety are referenced to Bing cherry trees growing in the same area under similar circumstances. | A new and distinct variety of self-fertile sweet cherry, Prunus avium, tree which bears medium to large 9.1-9.5 grams in weight firm mahogany-red colored fruits. Its exceptional, high quality, attractive fruits ripen four to five days ahead of the commercially grown Bing variety, which it is compared to herein. | 0 |
FIELD OF THE INVENTION
[0001] The present invention relates to CDMA2000 mobile networks, and more particularly to the interaction between always-on mobile data devices and third generation CDMA2000 networks.
BACKGROUND
[0002] In CDMA2000 networks it is important for a wireless data device to acquire and stay in a network that provides third generation (3G) data services such as email, browser and short message service (SMS) text messaging to the device. An always-on device should always try to keep a valid point-to-point protocol (PPP) session in order to send or receive data packets in a timely manner. When a mobile data device loses its PPP session or the device moves to a new network where, for example, the SID/NID/packet zone ID (system identification/network identification/packet zone identification) changes, the device should try to negotiate for a new PPP session with the network.
[0003] The problem with this, however, is that in current CDMA2000 networks there is no information broadcast to a mobile device on whether the network supports data services. The mobile device is merely notified that is has acquired a second generation (2G) or a 3G system.
[0004] Third generation systems do not always support data services. In some cases such a network only supports 3G voice services. In other situations such 3G networks might not have a data roaming agreement with the mobile device's home network, and therefore not allow the mobile device to access data services.
[0005] A mobile data device moving into a system that does not support 3G data currently wastes battery power by trying to establish a data connection with the network. Further, such attempts to establish a data connection waste network resources.
SUMMARY OF THE INVENTION
[0006] The present invention seeks to overcome the above deficiencies by providing a mobile data device with information about the capabilities of networks the device can connect to. Each mobile device includes a preferred roaming list (PRL) built into it, which assists the device to perform system selection and acquisition. This PRL includes the SID/NID pair Preference and Roaming Indication to aid the device in deciding whether the system is a preferred system that the device should connect to. In the present invention, information about whether the network supports 3G data capability is added to the PRL to assist a device in deciding whether it should connect to the network.
[0007] Other information that can be added to the PRL in the present invention includes whether the network supports data roaming for the device's home network. This allows the mobile data device to know whether the network can be connected to for data roaming services.
[0008] Also, with the advent of Mobile IP (Internet Protocol), a device prefers to connect to a network that supports Mobile IP rather than simple IP. This allows the device to move between networks with less time and effort spent establishing an IP connection. Information about whether the network supports Mobile IP can also be added to the PRL.
[0009] Further, with CDMA2000 networks, a device will prefer a packet data serving node that supports the always-on feature. Information about whether the network supports this feature can also be added to the PRL.
[0010] The new information provided to an always-on data device allows the device to create its own system preferences based on the 3G data capability of the network. If the network does not provide data capability, the device should search for a different network and not try to establish a PPP session, thereby saving batteries and network resources. Further, an attempt to connect to preferred networks, such as those that support Mobile IP data services and data roaming, should be made before attempting to connect to networks that do not support these services. The mobile data device should also try to stay in these networks whenever possible.
[0011] In present wireless devices, the device does not know what data service capabilities it has. The network stores this information, and resources may be wasted in attempting to utilize services the device does not support. A further possibility is therefore to include a field in the PRL to indicate what services the device supports. This will save battery life and network capacity by preventing the device from attempting to utilize a service it does not support.
[0012] The present invention therefore includes a method of providing a mobile data device in a wireless system with information about preferred networks to connect to, said mobile data device having a preferred roaming list with a list of networks, said method comprising the steps of: adding information to the preferred roaming list about data capabilities of each network; and determining preferred networks based on information within said preferred roaming list including a geographic area and the data capabilities of said network.
[0013] The present invention further includes a method of providing a mobile data device in a wireless system with information about preferred networks to connect to, said mobile data device having a preferred roaming list with a list of networks, said method comprising the steps of: adding information to the preferred roaming list about whether each said network in said list of networks supports third generation data capabilities; and determining preferred networks based on information within said preferred roaming list including a geographic area and whether said network supports third generation data capabilities whereby, within said geographic area, said mobile data device prefers those of said networks which support third generation data capabilities over said networks which do not support third generation data capabilities.
[0014] The present invention still further includes a method of providing a mobile data device in a wireless system with information about preferred networks to connect to, said mobile data device having a preferred roaming list with a list of networks, said method comprising the steps of: adding to the preferred roaming list information about whether each said network in said list of networks supports third generation data capabilities; adding to the preferred roaming list information about whether each said network in said list of networks supports data roaming; adding to the preferred roaming list information about whether each said network in said list of networks supports Mobile IP service; adding to the preferred roaming list information about whether each said network in said list of networks supports an always-on feature; and determining preferred networks based on information within said preferred roaming list including a geographic area and whether said network supports third generation data capabilities, data roaming, Mobile IP service and always-on feature; whereby, within said geographic area, said mobile data device firstly prefers those of said networks which support said third generation data capabilities over networks which do not support said third generation data capabilities, secondly prefers those of said networks which support said data roaming over networks which do not support said data roaming, thirdly prefers those of said networks which support said Mobile IP service over networks which do not support said Mobile IP service, and fourthly prefers those of said networks which support said always-on feature over networks which do not support said always-on feature.
[0015] The present invention still further includes A system for providing a mobile data device in a wireless system with information about preferred networks to connect to from a list of networks, said system comprising: the mobile data device, said mobile data device being capable of connecting to some or all networks within said list of networks; and a preferred roaming list within said mobile data device, said preferred roaming list including: identification information for each network within said list of networks; geographic information for each network within said list of networks; and information about each network within said list of networks indicating whether each network supports data capability; whereby said mobile data device chooses a preferred network based on said geographic information and those of said networks within said list of networks that supports said data capability.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The present invention will be better understood with reference to the drawings, in which:
[0017] FIG. 1 is a schematic diagram of a wireless device of the present invention; and
[0018] FIG. 2 is a flow diagram of a method of acquiring a system according to the method of the present invention.
DETAILED DESCRIPTION
[0019] Referring to the drawings, mobile data device 100 is preferably a two-way wireless communication device. Where mobile data device 100 is enabled for two-way communication, it will incorporate a communication subsystem 111 , including both a receiver 112 and a transmitter 114 , as well as associated components such as one or more, preferably embedded or internal, antenna elements 118 , local oscillators (LOs) 113 , and a processing module such as a digital signal processor (DSP) 120 . As will be apparent to those skilled in the field of communications, the particular design of the communication subsystem 111 will be dependent upon the communication network in which the device is intended to operate.
[0020] When required network registration or activation procedures have been completed, mobile data device 100 may send and receive communication signals over the network 119 . Signals received by antenna 116 through communication network 119 are input to receiver 112 , which may perform such common receiver functions as signal amplification, frequency down conversion, filtering, channel selection and the like, and analog to digital (A/D) conversion.
[0021] Mobile data device 100 preferably includes a microprocessor 138 , which controls the overall operation of the device. Communication functions are performed through communication subsystem 111 . Microprocessor 138 also interacts with further device subsystems such as the display 122 , flash memory 124 , random access memory (RAM) 126 , auxiliary input/output (I/O) subsystems 128 , serial port 130 , keyboard 132 , speaker 134 , microphone 136 , a short-range communications subsystem 140 and any other device subsystems generally designated as 142 .
[0022] Preferred roaming lists used by the microprocessor 138 during network registration are preferably stored in a persistent store such as flash memory 124 , which may instead be a read-only memory (ROM) or similar storage element (not shown).
[0023] As shown, flash memory 124 can be segregated into different areas for both programs storage 150 and preferred roaming list 152 .
[0024] Mobile devices 100 use preferred roaming lists to determine with whom contact should attempt to be established. This is useful when the mobile device loses the signal from the base station and a new signal needs to be acquired.
[0025] Table 1 shows an example of a PRL table as currently used by wireless devices 100 . One skilled in the art will realize that the information may be arranged differently depending on the mobile device, and that Table 1 is merely an example of a PRL table.
TABLE 1 INDEX SID NID N/PREF GEO PRI ACQ ROAM 0 253 65535 Pref NEW SAME 21 0 1 3682 65535 Pref SAME MORE 2 0 2 2157 65535 Pref SAME SAME 14 1 3 46 65535 Pref NEW SAME 6 0 4 257 65535 Pref SAME SAME 7 1
[0026] If a mobile device 100 loses its signal, the device will attempt to reestablish contact. This will be done based on the information in the PRL. This information includes whether the SID/NID pair is negative or banned, or preferred and desired, as indicated in the column labeled N/PREF.
[0027] The PRL further includes information about whether the SID/NID pair is in the same or different geographical area. In Table 1, most of the entries are marked SAME under the GEO column. This means that they are in the same geographical area as the previous index SID. When the column indicates NEW, this SID is in a different geographical area than the previous index SID. The mobile device will first attempt to establish contact with a system in the same geographical area as the signal it just lost.
[0028] The PRL then ranks the priority of each system. This is seen in the column labeled PRI in Table 1. SAME indicates that the SID has the same priority as the next indexed SID. MORE indicates that the SID has more priority than the next indexed SID.
[0029] In Table 1, if a mobile device loses the signal for SID 2157 , it first looks for a new network in the same geographical area, or within SIDS 253 , 3682 and 2157 . Within these areas the mobile device then looks for the highest priority networks, which in the example are SIDs 253 and 3682 . If these cannot be connected to, the mobile device moves to the next highest priority network, which in the example is SID 2157 .
[0030] ACQ is the acquisition index, which tells the mobile device which channels to look for signals on. Roam tells the mobile device what to do with the roam indicator.
[0031] As indicated above, the problem with current PRL system tables is that they do not tell the mobile device whether the SID/NID pair support third generation data capabilities. This could lead to a mobile data device attempting to make contact with a SID/NID pair that does not support data capability, thus wasting both battery power on the mobile device and network resources due to the attempt to establish contact.
[0032] Table 2 shows an example PRL system table using the method and system of the present invention. Table 2 includes a column that indicates whether the SID/NID pair supports third generation data communications. One skilled in the art will realize that there are other ways to amend a PRL table to indicate that the SID/NID pair supports data capability, and the table below is merely meant to be illustrative of one way to implement this.
TABLE 2 3G INDEX SID NID N/PREF GEO PRI ACQ ROAM Data 0 253 65535 Pref NEW SAME 21 0 0 1 3682 65535 Pref SAME MORE 2 0 1 2 2157 65535 Pref SAME SAME 14 1 1 3 46 65535 Pref NEW SAME 6 0 0 4 257 65535 Pref SAME SAME 7 1 1
[0033] Using the PRL system table of Table 2, a mobile device can determine whether to attempt to establish communications with an SID/NID pair. Using the above example, if the mobile device 100 loses contact with SID 2157 , it will attempt to establish contact based on the PRL table in Table 2. This is done by geography first in this case, but now also by 3G data capability. In the prior art model, the mobile device would have first attempted to establish contact with SID 253 . However, using the method of the present invention the mobile data device does not attempt to contact SID 253 since it does not support 3G data capability. This saves both battery power and system resources. The device instead attempts to communicate with SID 3682 first.
[0034] One skilled in the art will appreciate that the PRL table of Table 2 can also save resources by identifying to the mobile device that no SID/NID pair in the area supports data capability, and thus the system should not attempt to establish contact at all.
[0035] Table 2 overcomes many of the deficiencies of the prior art. However, an alternate preferred PRL table may also include information about whether the SID/NID pair allows data roaming. This is used, for example, if the mobile device is outside of its home system. Table 3 shows an example of a PRL that includes information about whether the SID/NID will allow data roaming.
TABLE 3 3G Data INDEX SID NID N/PREF GEO PRI ACQ ROAM Data Roam 0 253 65535 Pref NEW SAME 21 0 0 0 1 3682 65535 Pref SAME MORE 2 0 1 0 2 2157 65535 Pref SAME SAME 14 1 1 1 3 46 65535 Pref NEW SAME 6 0 0 0 4 257 65535 Pref SAME SAME 7 1 1 1
[0036] Table 3 includes the additional column for data roaming, indicating whether the network will accept data roaming. If it does not, the mobile data device that is not within that system as its home system will not attempt to establish communications with this SID.
[0037] Continuing with the above example, if the mobile device 100 is not within its home system for SID 3682 , it will know that 3682 does not allow roaming, and thus not attempt to establish contact with this system. The device will instead move to SID 2157 , which allows 3G data services and also allows roaming.
[0038] One skilled in the art will realize that 3G data and roaming may be combined or may be represented differently from the PRL system table of Table 3.
[0039] A further benefit would be to know whether the SID supports Mobile IP. Mobile IP allows a mobile device to move between SID/NID pairs without having to establish a simple IP. This presents significant benefits for roaming with mobile data devices.
[0040] A further preference criterion for a PRL can thus be whether the system supports Mobile IP. An example is illustrated in Table 4 below.
TABLE 4 3G Data Mobile INDEX SID NID N/PREF GEO PRI ACQ ROAM Data Roam IP 0 253 65535 Pref NEW SAME 21 0 0 0 1 1 3682 65535 Pref SAME MORE 2 0 1 0 1 2 2157 65535 Pref SAME SAME 14 1 1 1 0 3 46 65535 Pref NEW SAME 6 0 0 0 1 4 257 65535 Pref SAME SAME 7 2 1 1 1
[0041] In Table 4, the preference is first given by geography, then by 3G data capability, then by roaming, and finally by whether the network supports Mobile IP services.
[0042] A further benefit would be to know whether the packet data serving node (PDSN) supports an always-on feature. If the device is an always-on device and the PDSN supports an always-on feature, the PDSN is informed that the device is an always-on device and the device is informed about the maximum PPP inactivity time. Based on this, an always-on device would prefer to select a network that supports the always-on feature.
[0043] A further preference criterion for a PRL can thus be whether the system supports the always-on feature. An example is illustrated in Table 5 below.
TABLE 5 3G Data Mobile Always- INDEX SID NID N/PREF GEO PRI ACQ ROAM Data Roam IP On 0 253 65535 Pref NEW SAME 21 0 0 0 1 0 1 3682 65535 Pref SAME MORE 2 0 1 0 1 1 2 2157 65535 Pref SAME SAME 14 1 1 1 0 1 3 46 65535 Pref NEW SAME 6 0 0 0 1 0 4 257 65535 Pref SAME SAME 7 1 1 1 1 0
[0044] In Table 5, the preference is first given by geography, then by 3G data capability, then by roaming, then by whether network supports Mobile IP services, and finally by whether the network support an always-on feature. One skilled in the art will realize that preference can be given to networks using a different ordering of the PRL table data, and that in some cases various columns in the PRL table may be omitted altogether.
[0045] The implementation of the table can further be a single data capability field, in which, for example, an eight bit field could use various bits to signify whether the network supported always-on, mobile IP, 3G data and data roaming, or other data capability features. For example, the first bit in the field could signify that the network supported an always-on feature with a “1”, or that the network did not support the always-on feature with a “0”. The remaining bits could similarly be used for other data capability information.
[0046] In a wireless system where the mobile data device can connect to a plurality of networks, the above is implemented by amending the PRL table and the logic for establishing priority within the mobile device. The PRL table can be modified and loaded onto the mobile device through known methods within the art. Further, the mobile device can be programmed to select preferred networks based on the modified PRL table.
[0047] A further benefit would be to know whether the data device is able to support various services, such as voice, data, or SMS. The device is configured by the carrier for specific services based upon the service plan that the user selects. In the current CDMA2000 standard, the device is not aware of the service configuration file at the network. The device is aware of the service that the network supports only after it sends a service request that is granted or rejected by the network.
[0048] In operation, if the device wants to send an SMS message in a non-provisioned network, the device first sends an SMS origination request to set up a dedicated traffic channel. The device next sends an SMS message on the dedicated traffic channel. Finally the network checks whether the devices is entitled to the SMS service. If not, the network sends an SMS error code to the device.
[0049] By adding device service information to the PRL, the device has the ability to know its service capability at the time the network is acquired and without any service request being sent out. This saves battery life and system capacity by ensuring the device does not attempt to establish a service it does not have the capability for.
[0050] A further preference criterion for a PRL can thus be the device service capability. An example is illustrated in Table 6 below.
TABLE 6 Data Device Service INDEX SID NID N/PREF GEO PRI ACQ Capability Capability 0 253 65535 Pref NEW SAME 21 01100000 1010 1 3682 65535 Pref SAME MORE 2 00110000 1010 2 2157 65535 Pref SAME SAME 14 11010000 1010 3 46 65535 Pref NEW SAME 6 00010000 1010 4 257 65535 Pref SAME SAME 7 11110000 1010
[0051] In Table 6, the preference to the choice of network is made as above, with the data capability field using the first four bits to indicate 3G data, Mobile IP, Always-On PDSN and data roaming. The device further has information about what services it supports. In Table 6, the four bits can, for example, indicate whether the device supports data service (first bit), voice service (second bit), SMS (third bit) and browser (fourth bit). The device will thus know what types of service it can request.
[0052] In a preferred embodiment, the carrier could update the device by downloading a new PRL when the user changes their service plan. The device could further display the services it supports using an icon to indicate its service capability.
[0053] The above will be better understood with reference to FIG. 2 . In FIG. 2 , a mobile device 100 stays in step 200 until the device realizes that it needs to acquire a new system. If the device 100 does not need to acquire a new system, the device stays in step 200 .
[0054] Once mobile device 100 realizes it needs to acquire a new system, mobile data device 100 moves to step 202 in which it stats a search for a new system. In step 204 mobile device 100 determines whether it has acquired a new system.
[0055] In step 204 , if the device finds that it has not acquired a new system, the device moves back to step 202 in which a search for a new system is again started.
[0056] Conversely, if the device finds that a new system has been acquired, the device next moves to step 206 . In step 206 the device asks the PRL table whether the potential system supports third generation (3G) data capabilities. As indicated above, for a data device this is a key feature.
[0057] In step 206 if the device finds that the potential network does not support third generation data, the system next moves to step 208 . In step 208 the device asks whether any network that the device can access supports third generation data capability. If step 208 finds networks that support 3G data capability, the device will prefer to connect to those networks, and will thus move back to step 202 and start a search for a new system.
[0058] Conversely, if the network does not support third generation data capability, the device can either decide not to connect to a system (not shown) or can connect to the potential system acquired in step 204 .
[0059] If in step 206 the system that is found supports 3G data, the system next moves to step 210 . In step 210 the device asks whether this is the best system to connect to. The decision in step 210 is based on the PRL table and the information contained therein. Specifically, depending on the device, it may prefer systems that support mobile IP, data roaming or always-on capabilities. Based on the device and the PRL table, a decision is made in step 210 whether the potential system is the best system to acquire.
[0060] If step 210 finds that the best system is being acquired, the system next moves to step 212 and acquires the system. Conversely, if step 210 finds that a better system exists, the device moves back to step 202 and start a search for the new system.
[0061] 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. Also, various modifications, which would be readily apparent to one skilled in the art, are intended to be within the scope of the present invention. The only limitations to the scope of the present invention are set forth in the following claims appended hereto. | A method and system of providing a mobile data device in a wireless system with information about preferred networks to connect to, the mobile data device having a preferred roaming list with a list of networks, the method comprising the steps of: adding to the preferred roaming list information about whether each network in the list of networks supports third generation data capabilities; and determining preferred networks based on information within the preferred roaming list including a geographic area and whether the network supports third generation data capabilities, whereby, within the geographic area, the mobile data device prefers networks which support third generation data capabilities over networks which do not support said third generation data capabilities. Other information that may be added to the preferred roaming list includes whether the network supports data roaming, Mobile IP services or always-on features. The preferred roaming list may also include information about the device service capabilities. | 7 |
BACKGROUND OF THE INVENTION
The present invention relates to generally surface materials, and particularly, to surface materials which are suitable for use in absorbent articles such as sanitary napkins or disposable diapers and to the absorbent articles using such surface materials.
Conventionally, nonwoven fabrics obtained through a so-called air-through process have often been used as surface materials of absorbent articles such as disposable diapers or sanitary napkins. The air-through process comprises a step of subjecting a fibrous web such as a carded web laid on an air-permeable net or a drum to hot blast so as to heat-weld component fibers at intersections thereof.
The air-through nonwoven fabrics obtained through such process are characterized by comfortably airy texture. However, on the surface of such air-through nonwoven fabrics directly exposed to hot blast (referred to hereinafter as “hot blast-exposed surface”), the component fibers are generally apt to be raised.
Taking accounting of such tendency when the air-through nonwoven fabric is used as a surface material for the absorbent article, the surface of such type of nonwoven fabric opposite to the blown surface, i.e., the surface opposed to the net or the drum (referred to hereinafter as “net-side surface”) has usually been laid so as to face the article wearer's skin.
However, a fibrous layer on the net-side surface is not apt to become airy as easily as the hot blast-exposed surface is and, in many cases, remains in a state compressed in thickness direction thereof. Therefore, if the absorbent article is designed in a manner that the fibrous layer on the net-side surface is put in contact with the wearer's skin, there will be likely that at least a portion of body fluids discharged by the article wearer might stay on and/or soak through the surface material.
Recently, there is a demand for a tangibly improved texture of the absorbent article and it has already been proposed to design the absorbent article so that the hot blast-exposed surface of the air-through nonwoven fabric is opposed to the article wearer's skin (See REFERENCE: Japanese Unexamined Patent Application Publication No. 2004-166831).
In the case of the absorbent article disclosed in this REFERENCE, a diameter of each component fibers on the hot blast-exposed surface of the air-through nonwoven fabric is dimensioned as thin as in a range of 11 to 18 μm and thereby intersections of the component fibers are increased in order to alleviate the tendency that the component fibers would readily raise on the hot blast-exposed surface. Even in this case, however, it will be impossible to restrain the raising tendency to an acceptable degree because much more component fibers on the hot blast-exposed surface than those on the net-side surface are headed in the thickness direction of the nonwoven fabric.
The conventional technique according to which the absorbent article is designed so that the net-side surface of the surface material faces the wearer's skin may result in poor absorbency for body fluids discharged by the wearer for the reason as has been described above. On the other hand, the technique disclosed in REFERENCE according to which the absorbent article is designed so that the hot blast-exposed surface of the surface material faces the wearer's skin is unable to restrain the raising tendency to an acceptable degree and consequentially to achieve touch and feeling which are comfortable for the article wearer. Therefore, there is a demand for development of the air-through nonwoven fabric improved so as to solve the problems as have been described above.
SUMMARY OF THE INVENTION
In view of the problems as have been described above, it is an object of the present invention to provide a surface material and an absorbent article using the same wherein a thermally bondable fibrous layer on the side opposite to the hot blast-exposed surface is prevented from being fixed in a state compressed in the thickness direction as the surface material is exposed to hot blast and, in addition, to provide an absorbent article using such surface material.
The object set forth above is achieved, according to the present invention, an improvement in the surface material comprising fibrous web in which thermally bondable component fibers have been bonded together as these component fibers are exposed to hot blast, and having a hot blast-exposed surface and a surface opposite thereto, wherein the surface material comprises a first layer defining the hot blast-exposed surface so as to function as a buffer adapted to alleviate an influence of hot blast upon the surface opposite to the hot blast-exposed surface and a second layer defining the surface opposite to the hot blast-exposed surface.
The first layer's buffer function against hot blast herein specifically refers to the function which alleviates an influence of hot blast upon the surface opposite to the hot blast-exposed surface and thereby allows the second layer to become appropriately airy. More specifically, the surface material according to the present invention includes the first layer having such buffer function against hot blast so that an interfiber distance in the second layer on the surface opposed to the hot blast-exposed surface (i.e., the net-side surface) can be prevented from being excessively shortened (i.e., a density of the second layer is prevented from increasing). In this way, the problem that body fluids discharged by the article wearer may stay on or soak through the surface material even when the surface opposed to the hot blast-exposed surface is laid so as to face the article wearer's skin.
The first layer having the buffer function against hot blast may be formed, for example, by microporous plastic film having porosity in a range of 5 to 40%. Such microporous plastic film used as the first layer interfaces passage of hot blast and correspondingly buffers the influence of hot blast upon the second layer. If the porosity is less than 5%, an interfiber bond in the second layer would be insufficient and the component fibers in this second layer would be readily raised. If the porosity exceeds 40%, on the contrary, it would be impossible to assure the desired buffer function against hot blast and the interfiber distance in the second layer would be unacceptably shortened.
While a diameter of each micropore as well as an area of each micropore is not specified herein, the diameter is preferably in a range of 0.2 to 5.0 mm and more preferably in a range of 0.5 to 3.0 mm in order to ensure the buffer function against hot blast which is effective evenly over the whole area. The area of each micropore is preferably in a range of 0.03 to 30 mm 2 and more preferably in a range of 0.3 to 20 mm 2 .
Preferred film material may be selected from various types of thermoplastic resin such as polyethylene, polypropylene, polyethyleneterephthalate, polyvinyl alcohol, polylactic acid and polybutyl succinate. In any case, a thickness of the film is preferably in a range of 15 to 60 μm. A basis weight of the film is preferably in a range of 15 to 60 g/m 2 .
Furthermore, the microporous plastic film is preferably filled with inorganic filler such as titanium oxide, barium sulfate or calcium carbonate in order to prevent body fluids such as menstrual blood or urine from being seen through the article from the outside after passage through the film.
Moreover, the microporous plastic film used for the present invention is preferably mixed with or coated on its surface with suitable agent modifying the film to be hydrophilic in order that the hydrophilicity of the film can be improved and body fluids can smoothly pass through the micropores of the film.
The micropores may be formed optionally by any one of various processes such as embossing, perforating and tentering and also by filling the film material with said inorganic filler followed by orientation thereof. It should be noted that, when the plastic film formed with the micropores by perforation is used as the first layer, the first and second layers are placed upon each other preferably with edges of the respective micropores headed away from the second layer.
Generally, the second layer is preferably formed by fibers adapted to be thermally bonded together at a temperature as low as the micropored plastic film defining the first layer is not molten at this temperature. It should be understood that the second layer may be formed by either fibers of simplex structure or composite fibers of side-by-side structure, core-sheath structure, etc. In the latter case, the second layer is preferably formed by the composite fibers made primarily of high density polyethylene, polypropylene, etc. The first and second layers may be bonded together in such a manner that the component fibers of the second layer molten under the effect of hot blast may be bonded to the microporous plastic film, or may be partially bonded together by embossing or by means of appropriate adhesive such as hot melt adhesive.
When both the first layer and the second layer are made of fibrous material, the first layer can be provided with the desired buffer function against hot blast by meeting requirements as will be described below.
The first and second layers comprise one or more types of thermoplastic resin fibers and a melting point of thermoplastic resin contained in the second layer and having the highest melting point is higher than a melting point of thermoplastic resin contained in the first layer and having the highest melting point by 50° C. or more; the first layer comprises first and second fibers made of one or more types of thermoplastic resin while the second layer comprises third and fourth fibers made of one or more types of thermoplastic resin, a melting point of thermoplastic resin contained in the first fibers and having the highest melting point is higher than a melting point of thermoplastic resin contained in the second fibers and having the highest melting point by 50° C. or more, a differential melting point between a melting point of thermoplastic resin contained in the third fibers and a melting point of thermoplastic resin contained in the fourth fibers and having the highest melting point is less than 50° C. and a content of the second fibers with respect to all fibers contained in the first layer is 5 mass % or higher; and the first layer comprises first and second fibers made of one or more types of thermoplastic resin while the second layer comprises third and fourth fibers made of one or more types of thermoplastic resin, a melting point of thermoplastic resin contained in the first fibers and having the highest melting point is higher than a melting point of thermoplastic resin contained in the second fibers by 50° C. or more and having the highest melting point, a melting point of thermoplastic resin contained in the third fibers and having the highest melting point is higher than a melting point of thermoplastic resin contained in the fourth fibers by 50° C. or more, and a content of the second fibers with respect to all fibers contained in the first layer is higher than a content of the fourth fibers with respect to all fibers contained in the second layer by 5 mass % or more.
In the fibrous web formed by the fibers meeting the requirements as have been described above, thermal strain is generated in the component fibers of the first layer as this first layer is exposed to hot blast and consequentially the first layer buffers an influence of hot blast upon the second layer. At the same time, heat resistance is higher in the second layer than in the first layer and therefore it is not likely that the first layer might get soft and collapse more significantly than the first layer under the effect of hot blast.
While not specified so long as the requirements as have been described above are met, the type of thermoplastic resin may be preferably selected from polyolefin-based resin, polyester-based resin, polyamide-based resin and polyurethane-based resin.
Polyolefin-based resin may include low density polyethylene, high density polyethylene, polypropylene and modified polypropylene. Polyester-based resin may include polyethyleneterephthalate and copolymer polyester. Polyamide-based resin may include nylon.
While the above-described fibers may be either the fibers of simplex structure or composite fibers, more particularly composite fibers of core-sheath structure is preferable. When the composite fibers of core-sheath structure is used as the above-described fibers, a melting point of the resin defining the core is preferably higher than a melting point of the resin defining the sheath in order to ensure that the resin of the sheath is reliably fused together. Core-sheath ratio is preferably in a range of 70:30 to 30:70 and more preferably in a range of 60:40 to 40:60. It is possible also to use the core-sheath composite fibers in which the core is eccentric.
While the above-described fibers may be either hollow or solid, the second layer preferably comprises a combination of the solid fibers and the hollow fibers. Cross-section of the above-described fibers may be selected from circular shape, flat shape, Y-shape and C-shape.
Alternatively, either stereoscopically crimped fibers which is explicitly crimped or potentially crimped as it is heated, or split fibers adapted to split under a physical load such as water stream or embossing may be also used as the above-described fibers.
According to one preferred embodiment, in the first layer, the first fibers in the first layer is composite fibers made of polyolefin-based resin and polyester-based resin while the second fibers is composite fibers made of polyolefin-based resin. According to a particularly preferred embodiment, the first fibers are composite fibers made of polyethylene and polyethyleneterephthalate while the second fibers is composite fibers made of polyethylene and polypropylene.
As one embodiment of the invention, both the third and fourth fibers in the second layer may be composite fibers made of polyolefin-based resin and polyester-base resin. Alternatively, the third fibers may be composite fibers made of polyolefin-based resin and polyester-based resin while the fourth fibers may be composite fibers made of polyolefin-based resin. In the former case in which each of the third and fourth fibers is composite fibers made of polyolefin-based resin and polyester-based resin, this composite fibers is preferably made of polyethylene and polyethyleneterephthalate. In the latter case in which the third fibers is composite fibers made of polyolefin-based resin and the fourth fibers is composite fibers made of polyolefin-based resin, the third fibers is preferably made of polyethylene and polyethyleneterephthalate while the fourth fibers is preferably made of polyethylene and polypropylene.
Particularly in the first layer, on one hand, the first fibers is composite fibers of core-sheath structure consisting of the core formed by polyethyleneterephthalate and the sheath formed by polyethylene while the second fibers is composite fibers of core-sheath structure consisting of the core formed by polypropylene and the sheath formed by polyethylene wherein a mixing ratio of these first and second fibers is preferably in a range of 95:5 to 0:100, more preferably in a range of 90:10 to 20:80 and most preferably in a range of 85:15 to 75:25. In the second layer, on the other hand, each of the third and fourth fibers is composite fibers consisting of the core formed by polyethyleneterephthalate and the sheath formed by polyethylene or the third fibers is composite fibers consisting of the core formed by polyethyleneterephthalate and the sheath formed by polyethylene while the forth fibers is composite fibers of core-sheath structure consisting of the core formed by polypropylene and the sheath formed by polyethylene wherein a mixing ratio of these third and fourth fibers is preferably in a range of 100:0 to 20:80, more preferably in a range of 100:0 to 60:40 and most preferably in a range of 100:0 to 80:20.
In this way, both the first layer and the second layer reliably become airy so that the component fibers may be sufficiently spaced one from another to obtain the surface material being outstanding in air-permeability and drape characteristics.
Preferred examples of resin constituting the first to fourth fibers and melting points of the respective examples are shown in TABLE 1. These examples shown in TABLE 1 may be selectively used. Melting points of the respective examples can be measured by reading peak values of calorific capacity from a thermogram obtained by thermal analysis using a differential scanning calorimeter (DSC).
TABLE 1
Resin
MP (° C.)
Low density polyethylene (LDPE)
80-125
Linear low density polyethylene (LLDPE)
90-135
High density polyethylene (HDPE)
110-145
Polypropylene (PP)
155-175
Copolymer polypropylene
110-135
Copolymer polyester
100-120
Polyethyleneterephthalate (PET)
245-265
Nylon
210-225
Polyurethane
150-230
Also for the surface material in which both the first layer and the second layer are formed by fibrous material, the first through fourth fibers are preferably filled with inorganic filler such as titanium oxide, barium sulfate or calcium carbonate to assure a concealing effect. A content of such inorganic filler in the first through fourth fibers is preferably in a range of 0.2 to 50 mass %. For these first through fourth fibers each of which is composite fibers of core-sheath type, one or both of these core and sheath may be added with the inorganic filler. However, taking account of possibility that the inorganic filler might fall off from the fibers during the process for making the fibrous web, it is preferred to add only the core with the inorganic filler. In this case, a content of the inorganic is preferably in a range of 0.2 to 6 mass % with respect to the resin destined to form the core.
In view of the fact that the fibers made of thermoplastic resin is hydrophobic as has previously been described, at least one of the first through fourth fibers is preferably mixed with suitable agent modifying it to become hydrophilic or coated with such modifying agent to obtain the surface material which has a sufficiently high liquid-permeability to alleviate undesirable phenomenon of wet-back. In this case, the desired effect can be further reliably obtained by making such fibers treatment in a manner that the first layer facing the article wearer's skin becomes more hydrophilic than the second layer. As the agent modifying the fibers to become hydrophilic, for example, surface active agent or hydrophilic high-molecular compounds may be used. While the surface active agent to be used may be selected from those of well known art such as nonionic surface active agent, anionic surface active agent, cationic surface active agent and amphoteric surface active agent, the nonionic surface active agent and the anionic surface active agent are more preferable. These surface active agents may be used independently or in a combination of two or more thereof. The hydrophilic high-molecular compound to be used may be selected from polyvinyl alcohol, methyl cellulose, carboxylmethylcellulose, hydroxymethylcellulose, polyvinyl pyrrolidone, polystyrene sulfonic acid, polyalkylpolyamine salt and alkali metal salt of polyethylene oxide. These hydrophilic high-molecular compounds may be used independently or in a combination of two or more thereof. Preferably, one or more of the hydrophilic high-molecular compounds are used in combination with one or more of the above-described surface active agents. Depending on desired hydrophilicity of the first through fourth fibers, it is possible also to treat the fibers with water repellent agent. As the water repellent agent, for example, silicone oligomer or fluorine oligomer may be used. As the typical silicone oligomer, polydimethyl silicone of chain structure is often used and polymethylphenyl silicone or polyfluorosilicone having methyl-groups partially substituted with phenyl-group or trifluoropropyl-group, respectively, may be also used. As the fluorine oligomer, polymeric acrylic ester of alcohol including perfluoroalkyl-group or phosphate ester may be used. These oligomers may be used independently or in a combination of two or more thereof.
In the first layer, mixing ratio between the fibers modified to be hydrophilic and water-repellent treated fibers is preferably in a range of 100:0 to 60:40 and, in the second layer, mixing ratio between the fibers modified to be hydrophilic and water-repellent treated fibers is preferably in a range of 0:100 to 70:30.
Both the first layer and the second layer may contain, in addition to the first through fourth fibers as have been described above, hydrophilic cellulosic fibers such as pulp, chemical pulp, rayon, acetate and natural cotton. It should be noted that a content of such cellulosic fibers with respect to the surface material as a whole is preferably up to 0.1 to 5 mass % and such cellulosic fibers should be contained preferably only in the first layer.
The surface material comprising the first layer and the second layer has, as a whole, a basis weight preferably in a range of 14 to 80 g/m 2 and more preferably in a range of 20 to 45 g/m 2 . If the basis weight of the surface material is less than 14 g/m 2 , the wet-back phenomenon would readily occur and, if the basis weight exceeds 80 g/m 2 , a spot absorbency would decrease. The first layer has a basis weight preferably in a range of 5 to 40 g/m 2 and more preferably in a range of 8 to 30 g/m 2 . The first layer having such basis weight has a density preferably in a range of 0.03 to 0.20 g/cm 3 and more preferably in a range of 0.05 to 0.15 g/cm 3 . The second layer has a basis weight preferably in a range of 5 to 40 g/m 2 and more preferably in a range of 10 to 30 g/m 2 . The second layer having such basis weight has a density preferably in a range of 0.01 to 0.15 g/cm 3 and more preferably in a range of 0.02 to 0.10 g/cm 3 . Setting of the basis weights and the densities to the ranges as have been indicated above facilitates the first layer to function as buffer against hot blast, on one hand, and effectively alleviates the wet-back phenomenon possibly occurring in the first layer, on the other hand, and assures an appropriate strength of the second layer to ensure that body fluids smoothly move from the second layer to the first layer.
The surface material comprising the first layer and the second layer has, as a whole, a thickness preferably in a range of 0.3 to 4.0 mm and more preferably in a range of 0.5 to 2.0 mm as measured under a pressure of 3 g f/cm 2 . The surface material having such range of thickness is able to maintain an appropriate flexibility. A thickness ratio between the first layer and the second layer is preferably in a range of 10:90 to 70:30 as measured under no pressure. Setting of the thickness and the thickness ratio to the ranges as have been indicated above allows body fluids to move rapidly from the second layer to the first layer.
To obtain improved air-permeability and touch, the first through fourth fibers have fineness preferably in a range of 0.1 to 6.6 dtex and more preferably in a range of 1.0 to 4.4 dtex.
To ensure that the component fibers are reliably heat-bonded together and are appropriately spaced one from another, a fibers length of the component fibers forming the first layer and the second layer may be selected upon a particular process for making the fibrous web. When the fibers is carded to open it, a fibers length is preferably in a range of 20 to 100 mm and more preferably in a range of 38 to 64 mm in order to obtain a texture formation as even as possible. When the fibers is air laid to open it, a fibers length is preferably in a range of 1 to 30 mm and more preferably in a range of 2 to 10 mm in order to obtain a texture formation as even as possible.
The first layer as well as the second layer may be fibrous web obtained by any one of the air-through process, the point bond process, the air laid process, dry spun lace process, the chemical bond process, etc. or a combination thereof. In an example of such composite process comprising two or more processes, fibrous web is accumulated on the air-permeable net as the second layer after having passed through the card and then ultrafine fibers are melt-blown onto the second layer so as to be accumulated thereon as the first layer. Alternatively, fibrous web may be accumulated on the air-permeable net as the second layer after having passed through the card and then short fibers each having a fibers length in a range of 1 to 30 mm may air laid thereon as the first layer. In this way, the first layer is obtained in the form of fibers assembly in which an interfiber distance is sufficiently small to obstruct passage of hot blast therethrough and thereby to restrain an interfiber distance of the second layer to an appropriate range. In further another example, fibrous web may be accumulated on the air-permeable net as the second layer after having passed through the card and then fibrous web may be formed on the second layer form the first layer by the point bond process, spun lace process or spun bond process. Among these processes, the air-through process is most preferable. The air-through process provides comfortable airy texture, sufficiently high liquid-permeability to alleviate undesirable wetback phenomenon and thereby the surface material of comfortable touch.
Preferred process for making the surface material according to the present invention will be described with respect to the air through process in which the first fibers are composite fibers of polyethyleneterephthalate/polyethylene core-sheath structure, the second fibers are composite fibers of polypropylene/polyethylene core-sheath structure, and both the third and fourth fibers are composite fibers of polyethyleneterephthalate/polyethylene core-sheath structure.
<Step of Stacking>
The fibrous assembly comprising the first fibers and the second fibers is opened by a first card to obtain carded web defining the first layer. The fibrous assembly comprising the third and the fourth fibers is opened by a second card to obtain carded web defining the second layer. The carded web is stacked on the air-permeable conveyor net made of wire mesh and then the carded web defining the first layer is stacked on the air-permeable net.
<Oven Step>
During conveyance of the web, hot blast at a predetermined temperature is blown out from a blower provided above the air-permeable net. Below the air-permeable net, a suction mechanism is provided to suck hot blast blown out from the blower.
A velocity of hot blast is preferably in a range of 0.2 to 2.0 m/sec and more preferably in a range of 0.5 to 1.0 m/sec. If the velocity of hot blast exceeds 2.0 m/sec, pressure of hot blast excessively compress the fibrous web as a whole against the net and prevent the fibrous web from becoming airy. If the velocity of hot blast is less than 0.2 m/sec, on the contrary, it will be difficult hot blast to exert evenly on the fibrous web over the entire area. A temperature of hot blast is preferably in a range of a melting point of the sheath resin in the composite fibers to be used minus 10° C. to this melting point plus 40° C. If the sheath resin is polyethylene, the optimal temperature of hot blast is in a range of 110 to 150° C. If the temperature of hot blast is less than the above-indicated range, the component fibers will be insufficiently bonded together resulting in an apprehension that the component fibers may be raised and/or the component fibers may partially fall off from the assembly. If the temperature of hot blast is exceeds the above-identified range, on the contrary, the thermal strain of the fibers will notably occur and the interfiber distance will be correspondingly reduced resulting in a compressed state of the fibrous web as a whole. A velocity at which the fibrous web is conveyed under hot blast is most preferably in a range of 60 to 200 m/min from the viewpoint of productivity as well as evenness of texture formation. A time for which the fibrous web stays within the oven is approximately 3 to 10 sec.
<Optional Steps>
One or more of the steps as will be described below may be optionally incorporated in the process.
Step of line tension: Before stacked on the second layer, a line tension in the direction of conveyance may be exerted upon the carded web defining the first layer. Such step of line tension causes the interfiber distance of the component fibers in the first layer to be reduced and facilitates the first layer to function as the buffer against hot blast. The preferred interfiber distance of the component fibers in the first layer is preferably in a range of 5 to 200 μm and more preferably in a range of 20 to 100 μm to ensure that the first layer effectively functions as the buffer against hot blast.
Step of cooing: The fibrous web may be cooled immediately after the oven step. For this step, the cooling system usually used for this purpose, for example, the system conveying the fibrous web along a chilling drum within which coolant water circulates or the system to blow out cold blast against the fibrous web may be used. Such step of cooling prevents the fibrous web from becoming narrow and/or collapsing even when a line tension is exerted on the fibrous web because, after the fibrous web has been subjected to the step of cooling, the fibers orientation is not easily changed and an appropriate interfiber distance is maintained.
Step of smoothing treatment: If the first layer and the second layer of the fibrous web obtained after the oven step have respective surfaces which are not smooth, the nonwoven fabric may guided along a heated roll.
When the fibrous web obtained as has been described above is used as the surface material for the absorbent article, an absorbent core is interposed between such fibrous web and the liquid-impervious sheet material. Such absorbent article is preferably designed so that the surface opposite to the hot blast-exposed surface, i.e., the second layer faces the article wearer's skin. It is possible to interpose a cushion sheet between the surface material and the absorbent core. The surface material may be embossed in order to form the surface material with the micropores and irregularities. In this case, it is also possible to emboss the surface material together with the cushion sheet.
The surface material according to the present invention may be used for various types of the absorbent article such as sanitary napkin and disposable diaper.
The present invention can provide the surface material in which the thermally bondable fibrous layer opposite to the hot blast-exposed surface is well protected from being put in a compressed state in the thickness direction thereof as this surface material is exposed to hot blast.
Various advantages are provided by the absorbent article using this surface material in a manner that the surface thereof opposite to the hot blast-exposed surface is adapted to face the article wearer's skin. Specifically, there is substantially no anxiety that body fluids discharged by the article wearer might stay on and/or soak through the surface material and the article wearer might suffer from stuffiness, itch or the other skin disorders.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a microscopic cross-sectional photo of the surface material according to Example 1 (×120);
FIG. 2 is a microscopic cross-sectional photo of the surface material according to Example 2 (×120);
FIG. 3 is a microscopic cross-sectional photo of the surface material according to Example 3 (×120);
FIG. 4 is a microscopic cross-sectional photo of the surface material according to Example 4 (×120);
FIG. 5 is a microscopic cross-sectional photo of the surface material according to Comparative Example 1 (×120);
FIG. 6 is a microscopic cross-sectional photo of the surface material according to Example 5 (×90);
FIG. 7 is a microscopic cross-sectional photo of the surface material according to Example 6 (×90); and
FIG. 8 is a microscopic cross-sectional photo of the surface material according to Comparative Example 2 (×90).
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention will be exemplarily described more in more details. It should be noted here that the present invention is not limited to these examples mentioned below.
Example 1
Core-sheath type polyethyleneterephthalate/polyethylene composite fibers each having a fineness of 2.6 dtex were coated with a hydrophilic agent and thereby fibers A was obtained. Similarly, core-sheath type polypropylene/polyethylene composite fibers having a fineness of 3.3 dtex were coated with the hydrophilic agent and thereby fibers B were obtained. The fibers A and the fibers B were mixed together at a mass ratio of 70:30. In both the fibers A and the fibers B, a core/sheath mass ratio was 50:50. A fibrous assembly obtained by mixing the fibers A and the fibers B was opened by the card at a rate of 20 m/min and thereby a carded web defining the first layer was obtained. The carded web obtained in this manner had a basis weight of 25 g/m 2 .
Aside from this, core-sheath (macaroni) type polyethyleneterephthalate/polyethylene composite fibers having a fineness of 2.6 dtex was coated with a hydrophilic agent and thereby fibers C were obtained. Core-sheath type polyethyleneterephthalate/polyethylene composite fibers having a fineness of 2.2 dtex was coated with a water repellent agent and thereby fibers D were obtained. The fibers C and the fibers D were mixed together at a mass ratio of 50:50. In both the fibers C and the fibers D, a core/sheath mass ratio was 50:50. A fibrous assembly obtained by mixing the fibers C and the fibers D was opened by the card at a rate of 20 m/min and thereby a carded web defining the second layer was obtained. The carded web obtained in this manner had a basis weight of 10 g/m 2 .
The carded webs defining the first layer and the second layer, respectively, were subjected to line tension.
The carded web defining the second layer was laid on a air-permeable net comprising a 20-mesh wire mesh and then the carded web defining the first layer was stacked thereon.
Hot blast at a temperature of 139° C. and a velocity of 0.6 m/sec was exerted on the fibrous assembly from the side of the first layer for approximately 5 sec while the air-permeable net is running at a velocity of 80 m/min. Consequently, intersections of the component in the web were thermally bonded together and the surface material made of the air-through nonwoven fabric was obtained. FIG. 1 is a microscopic cross-sectional photo of this surface material.
Example 2
The same fibers A and fibers B as used in EXAMPLE 1 were used and the carded web defining the first layer were obtained substantially in the same manner as in EXAMPLE 1 except that the these fibers A and B were mixed together at a mixing ratio of 60:40. The carded web had a basis weight of 20 g/m 2 .
Similarly, the same fibers C and fibers D as used in EXAMPLE 1 were used and the carded web defining the second layer substantially in the same manner as in EXAMPLE 1 except that the carded web had a basis weight of 15 g/m 2 .
Subsequent steps were performed in the same conditions as in EXAMPLE 1 to obtain the surface material made of the air-through nonwoven fabric. FIG. 2 is a microscopic cross-sectional photo of this surface material.
Example 3
The same fibers A and fibers B as used in EXAMPLE 1 were used and the carded web defining the first layer were obtained substantially in the same manner as in EXAMPLE 1 except that the these fibers A and B were mixed together at a mixing ratio of 54:46. The carded web had a basis weight of 17.5 g/m 2 .
Similarly, the same fibers C and fibers D as used in EXAMPLE 1 were used and the carded web defining the second layer substantially in the same manner as in EXAMPLE 1 except that the carded web had a basis weight of 17.5 g/m 2 .
Subsequent steps were performed in the same conditions as in EXAMPLE 1 to obtained the surface material made of the air-through nonwoven fabric. FIG. 3 is a microscopic cross-sectional photo of this surface material.
Example 4
The same fibers A and fibers B as used in EXAMPLE 1 were used and the carded web defining the first layer were obtained substantially in the same manner as in EXAMPLE 1 except that the these fibers A and B were mixed together at a mixing ratio of 20:80. The carded web had a basis weight of 10 g/m 2 .
Similarly, the same fibers C and fibers D as were used in EXAMPLE 1 were used and the carded web defining the second layer substantially in the same manner as in EXAMPLE 1 except that the carded web had a basis weight of 25 g/m 2 .
Subsequent steps were performed in the same conditions as in EXAMPLE 1 to obtained the surface material made of the air-through nonwoven fabric. FIG. 4 is a microscopic cross-sectional photo of this surface material.
Comparative Example 1
The same fibers C and fibers D as used in EXAMPLE 1 were mixed together at a mass ratio of 80:20. The fibrous assembly obtained by mixing the fibers C and D were opened by the card at a rate of 20 m/min and thereby the carded web was obtained. The basis weight was 35 g/m 2 . Then, this carded web was subjected to a line tension and laid on the air-permeable net comprising the 20-mesh wire mesh.
Hot blast at a temperature of 139° C. and a velocity of 0.6 m/sec was exerted on the fibrous assembly from one side of the first layer for approximately 5 sec while the air-permeable net was running at a velocity of 80 m/min. Consequently, intersections of the component in the web were thermally bonded together and the surface material comprising the air-through nonwoven fabric was obtained. FIG. 5 is a microscopic cross-sectional photo of this surface material.
Constituents as well as fibers structures of fibers A through D defining the respective layers in the surface materials of EXAMPLES 1 through 4 and COMPARATIVE EXAMPLE 1 are set forth in TABLE 2.
TABLE 2 Ex. 1 1st Fibers A: PET/PE core-sheath type; fineness of 2.2 dtex; layer coated with agent to modify it hydrophilic Fibers B: PP/PE core-sheath type; fineness of 3.3 dtex; coated with agent to modify it hydrophilic Basis weight ratio: A:B = 70:30; basis weight: 25 g/m 2 2nd Fibers C: PET/PE core-sheath macaroni type; fineness of layer 2.6 dtex; coated with agent to modify it hydrophilic Fibers D: PET/PE core-sheath type; fineness of 2.2 dtex, coated with repellent Basis weight ratio: C:D = 50:50; basis weight: 10 g/m 2 Ex. 2 1st Fibers A: PET/PE core-sheath type; fineness of 2.2 dtex; layer coated with agent to modify it hydrophilic Fibers B: PP/PE core-sheath type; fineness of 3.3 dtex; coated with agent to modify it hydrophilic Basis weight ratio: A:B = 60:40; basis weight: 20 g/m 2 2nd Fibers C: PET/PE core-sheath macaroni type; fineness of layer 2.6 dtex; coated with agent to modify it hydrophilic Fibers D: PET/PE core-sheath type; fineness of 2.2 dtex; coated with repellent Basis weight ratio: C:D = 50:50; basis weight: 15 g/m 2 Ex. 3 1st Fibers A: PET/PE core-sheath macaroni type; fineness of layer 2.2 dtex; coated with agent to modify it hydrophilic Fibers B: PP/PE core-sheath type; fineness of 3.3 dtex; coated with agent to modify it hydrophilic Basis weight ratio: A:B = 54:46; basis weight: 17.5 g/m 2 2nd Fibers C: PET/PE core-sheath macaroni type; fineness of layer 2.6 dtex; coated with agent to modify it hydrophilic Fibers D: PET/PE core-sheath type; fineness of 2.2 dtex; coated with repellent Basis weight ratio: C:D = 50:50; basis weight: 17.5 g/m 2 Ex. 4 1st Fibers A: PET/PE core-sheath type; fineness of 2.2 dtex; layer coated with agent to modify it hydrophilic Fibers B: PP/PE core-sheath type; fineness of 3.3 dtex; coated with agent to modify it hydrophilic Basis weight ratio: A:B = 20:80; basis weight: 25 g/m 2 2nd Fibers C: PET/PE core-sheath macaroni type; fineness of layer 2.6 dtex; coated with agent to modify it hydrophilic Fibers D: PET/PE core-sheath type; fineness of 2.2 dtex; coated with repellent Basis weight ratio: C:D = 50:50; basis weight: 10 g/m 2 Com- Fibers C: PET/PE core-sheath macaroni type; fineness of para- 2.6 dtex; coated with agent to modify it hydrophilic tive Fibers D: PET/PE core-sheath type; fineness of 2.2 dtex; ex. 1 coated with repellent Basis weight ratio: C:D = 80:20; basis weight: 35 g/m 2
All ratios set forth in EXAMPLE 2 are mass ratios. In any of the fibers A through D, the mass ratio between the core and the sheath is core:sheath=50:50.
Example 5
The same fibers A, fibers B and fibers D as used in EXAMPLE 1 and were used and the carded web defining the first layer were obtained substantially in the same manner as in EXAMPLE 1 except that the these fibers A, B and D were mixed together at a mixing ratio of 75:5:20. The carded web had a basis weight of 10 g/m 2 .
The same fibers C and fibers D as used in EXAMPLE 1 were used and the carded web defining the second layer was obtained substantially in the same manner as in EXAMPLE 1 except that these fibers C and D were mixed together at a mixing ratio of 80:20. The carded web had a basis weight of 25 g/m 2 .
Without exerting any line tension on the first layer and the second layer, the carded web defining the second layer was stacked on the air-permeable net comprising 20-mesh wire mesh and then the carded web defining the first layer was stacked thereon.
Hot blast at a temperature of 131° C. and an air flow of 20 Hz was exerted on the fibrous assembly from the side of the first layer for approximately 30 sec while the air-permeable net was running at a velocity of 3 m/min. Consequently, intersections of the component in the web were thermally bonded together and the surface material comprising the air-through nonwoven fabric was obtained. FIG. 6 is a microscopic cross-sectional photo of this surface material.
Example 6
As the component fibers of the first layer, the same fibers B and fibers D as used in EXAMPLE 1 and the carded web defining the first layer was obtained substantially under the same conditions as in EXAMPLE 1 except that these fibers were mixed together at a mass ratio of 80:20. The first layer had a basis weight of 10 g/m 2 .
As the component fibers of the second layer, the same fibers C and fibers D as used in EXAMPLE 1 and the carded web defining the second layer was obtained substantially under the same conditions as in EXAMPLE 1 except that these fibers were mixed together at a mass ratio of 80:20. The second layer had a basis weight of 25 g/m 2 .
Without exerting any line tension on the first layer and the second layer, the carded web defining the second layer was stacked on the air-permeable net comprising 20-mesh wire mesh and then the carded web defining the first layer was stacked thereon.
Hot blast at a temperature of 131° C. and an air flow of 20 Hz was exerted on the fibrous assembly from the side of the first layer for approximately 30 sec while the air-permeable net was running at a velocity of 3 m/min. Consequently, intersections of the component in the web were thermally bonded together and the surface material comprising the air-through nonwoven fabric was obtained. FIG. 7 is a microscopic cross-sectional photo of this surface material.
Comparative Example 2
The same fibers C and fibers D as used in EXAMPLE 1 were mixed together at a mass ratio of 80:20. Fibrous assembly obtained by mixing these fibers C and D was opened by the card at a rate of 20 m/min to obtain the desired carded web. This carded web had a basis weight of 35 g/m 2 . Without exerting any substantial line tension thereon, the carded web was laid on the air-permeable net comprising 20-mesh wire mesh.
Hot blast at a temperature of 131° C. and an air flow of 20 Hz was exerted on the fibrous assembly from one side of the first layer for approximately 30 sec while the air-permeable net was running at a velocity of 3 m/min. Consequently, intersections of the component in the web were thermally bonded together and the surface material comprising the air-through nonwoven fabric was obtained. FIG. 8 is a microscopic cross-sectional photo of this surface material.
Constituents as well as fibers structures of fibers A through D defining the respective layers in the surface materials of EXAMPLES 5, 6 and COMPARATIVE EXAMPLE 2 are set forth in TABLE 3.
TABLE 3 Ex. 5 1st Fibers A: PET/PE core-sheath type; fineness of 2.2 dtex; layer coated with agent to modify it hydrophilic Fibers B: PP/PE core-sheath type; fineness of 3.3 dtex; coated with agent to modify it hydrophilic Fibers D: PET/PE core-sheath type; fineness of 2.2 dtex; coated with repellent Basis weight ratio: A:B:D = 75:5:20; basis weight: 10 g/m 2 2nd Fibers C: PET/PE core-sheath macaroni type; fineness of layer 2.6 dtex; coated with agent to modify it hydrophilic Fibers D: PET/PE core-sheath type; fineness of 2.2 dtex; coated with repellent Basis weight ratio: C:D = 80:20; basis weight: 25 g/m 2 Ex. 6 1st Fibers B: PET/PE core-sheath type; fineness of 3.3 dtex; layer coated with agent to modify it hydrophilic Fibers D: PET/PE core-sheath type; fineness of 2.2 dtex; coated with repellent Basis weight ratio: B:D = 80:20; basis weight: 10 g/m 2 2nd Fibers C: PET/PE core-sheath macaroni type; fineness of layer 2.6 dtex; coated with agent to modify it hydrophilic Fibers D: PET/PE core-sheath type; fineness of 2.2 dtex; coated with repellent Basis weight ratio: C:D = 80:20; basis weight: 25 g/m 2 Com- Fibers C: PET/PE core-sheath macaroni type; fineness of para- 2.6 dtex; coated with agent to modify it hydrophilic tive Fibers D: PET/PE core-sheath type; fineness of 2.2 dtex; ex. 2 coated with repellent Basis weight ratio: C:D = 80:20; basis weight: 35 g/m 2
All ratios set forth in EXAMPLE 2 are mass ratios. In any of the fibers A through D, the mass ratio between the core and the sheath is core:sheath=50:50.
Basis weight, thickness and density of the surface materials respectively set forth in EXAMPLES 1 through 6 and COMPARATIVE EXAMPLES 1 and 2 are shown in TABLE 4 below.
TABLE 4
Basis weight
Thickness
Density
[g/m 2 ]
[mm]
[g/cm 3 ]
Example 1
36.2
0.58
0.062
Example 2
36.3
0.62
0.059
Example 3
36.1
0.65
0.056
Example 4
35.8
1.06
0.034
Comparative
35.1
0.52
0.068
example 1
Example 5
34.9
1.98
0.018
Example 6
34.4
1.89
0.018
Comparative
36.7
1.96
0.019
example 2
As will be apparent from FIGS. 1 through 5 , the second layers of the respective surface materials ( FIGS. 1 through 4 ) according to EXAMPLES 1 through 4 are not excessively collapsed in comparison with the associated first layers. In contrast therewith, the surface material ( FIG. 5 ) according to COMPARATIVE EXAMPLE 1 is significantly collapsed and the interfiber distance is apparently reduced.
As will be apparent from FIGS. 6 through 8 , the second layers of the respective surface materials ( FIGS. 6 and 7 ) according to EXAMPLES 5 and 6 also are not excessively collapsed in comparison with the associated first layers. In contrast therewith, the surface material ( FIG. 8 ) according to COMPARATIVE EXAMPLE 2 is significantly collapsed and the interfiber distance is apparently reduced.
For the surface materials according to respective Examples and respective Comparative Examples, liquid residual ratio and liquid spreading were evaluated using methods as will be described below. Result of these evaluations will be shown in TABLE 5.
<Preparation of Specimen for Evaluation>
The air-through nonwoven fabric obtained by the process as has been described above was partially cut off to prepare a specimen for evaluation each dimensioned to be 100 mm in longitudinal direction×60 mm in transverse direction (machine direction during the process for making the air-through nonwoven fabric corresponds to the longitudinal direction). On the other hand, NB pulp was wrapped with tissue paper having a basis weight of 15 g/m 2 , then partially cut off to a size of 100 mm in the longitudinal direction×60 mm in the transverse direction and compressed in the thickness direction to obtain an absorbent pad having a basis weight of 500 g/m 2 and a density of 0.09 g/cm 3 .
<Test Method>
The specimen was placed upon the absorbent pad with the second layer facing upward.
Acrylic board centrally formed with an opening dimensioned to be 40 mm in the longitudinal direction×10 mm in the transverse direction was placed upon the specimen for evaluation so that a center of the opening may fall substantially on the center of the specimen. The acrylic board was dimensioned to be 200 mm in the longitudinal direction×100 mm in the transverse direction and had a weight of 130 g.
A burette was fixed at a position so that its nozzle may be spaced 10 mm above the acrylic board and from this nozzle 3 ml of artificial menstrual blood was dropped at a dropping rate of 95 ml/min onto the specimen. Composition of the artificial menstrual blood is shown in TABLE 6 below.
One minute after dropping of artificial menstrual blood had been started, the acrylic board was removed.
Specimens (N=10) for each EXAMPLE were tested and an average value was obtained.
<Measuring Method>
Weight [g] (1) of the specimen prior to dropping of artificial menstrual blood and weight [g] (2) of the same specimen after dropping of artificial menstrual blood were measured.
Liquid residual ratio was calculated from an equation as follows:
Liquid residual ratio={(2)−(1)}/(1)×100(%)
Longitudinal dimension [mm] (3) and transverse dimension [mm](4) were measured using a ruler.
TABLE 5
Liquid Spreading
Liquid
Longitudinal
Transverse
Area
residual
dimension [mm]
dimension [mm]
[mm 2 ]
ratio [%]
Example 1
44
13
572
2.15
Example 2
43
13
559
1.79
Example 3
42
12
504
1.61
Example 4
42
11
462
0.57
Comparative
49
19
931
3.97
example 1
Example 5
36
17
612
1.36
Example 6
34
16
544
1.04
Comparative
38
19
722
5.43
example 2
TABLE 6
Aqueous solution containing
Carboxymethylcellulose sodium of 0.7 wt %,
Glycerin of 7.2 wt %,
Sodium chloride of 0.9 wt %,
Sodium bicarbonate of 0.4 w %,
Edible dye compound “Food Red” of 0.9 wt %
and
Edible dye compound “Food Yellow” of 0.2 wt %
was prepared.
Viscosity of this aqueous solution was in a range of
22 to 26 mPa · s as measured using VISMETRON Model VGA 4
available from SHIBAURA SYSTEM Co., Ltd.
As will be understood from TABLE 5, the surface material according to the present invention which is provided with the first layer having a buffer function against hot blast as has been described above with respect to Examples 1 through 6 is superior to those described as Comparative Examples 1 and 2 in the aspect that any unacceptable spreading of artificial menstrual blood can be effectively prevented and liquid residual ratio can be significantly reduced.
The entire discloses of Japanese Patent Application No. 2005-203732 filed on Jul. 12, 2005 including specification, drawings and abstract are herein incorporated by reference in its entirety. | A surface material for an absorbent article includes a fibrous web formed by thermally bondable component fibers bonded together under the effect of a hot blast and has a hot blast-exposed surface and a surface opposite to this hot blast-exposed surface. The fibrous web includes, in turn, a first layer lying on the side of the hot blast-exposed surface and having a buffering function to alleviate an influence of the hot blast upon the surface opposite to this hot blast-exposed surface, and a second layer lying on the side opposite to the hot blast-exposed surface. | 3 |
[0001] (Divisional of US patent application Ser. No. 09/476,968, filed on Dec. 30, 1999, claiming priority from CA patent application 2,293,134) This invention relates to a cold starting aid system for internal combustion engines.
BACKGROUND OF THE INVENTION
[0002] Air-cooled internal combustion engines are employed in a variety of applications in everyday life, from mopeds to family transport, large trucks, and industrial power plants. Today's engines are designed to operate reliably within a limited temperature range, typically between −20° C. to 40° C. When faced with extreme operating conditions, such as low temperatures, consistent engine start up and operation cannot be relied upon without assistance.
[0003] In order to initiate the combustion of an air/fuel mixture in a combustion chamber of an engine, the internal energy of the mixture must be raised to a critical level. For gasoline engines, this is typically accomplished through a compression of the air/fuel mixture and a subsequent ignition supplied by a spark plug. If the engine start up is not achieved immediately, then power, supplied by a battery is used to crank the engine over an extended period of time until the engine starts. In extreme cold conditions, a block heater can sometimes be relied upon, to warm up the engine block and, thereby, raise the internal energy of the fuel and air closest to the combustion chamber, in combination with the compression cycle and the ignition spark. The disadvantages of this start up aid is that it expends energy not used during start up, it requires time to warm up the engine block before starting can be tried, and an external energy source must be used to power the block heater. It is not uncommon for the battery to run out of charge at extreme cold temperatures before achieving start up.
[0004] In operation with diesel engines in extreme temperature conditions, raising the internal energy of the air/fuel mixture is accomplished by compression of the air/fuel mixture only, or by compression and the use of an electric glow plug. These starting systems are suitable only for smaller size engines with high compression ratio and high RPM (automobile diesel engines). Larger engines, like the ones of transport trucks, require different starting aids. Some are using the same block heaters as for the gasoline engines. The block heaters are not usually relied upon because of inaccessibility en-route (no external power source to connect the heater). Therefore, at low temperatures, it is not uncommon to leave the engine running rather than risk restart. Also, the use of a block heater is practical where the engine is water-cooled, but in some applications air cooled engines are preferred. The start up of diesel engines can also experience other disadvantages, namely running down of the battery, extended start up times, and excessive use of power resources.
[0005] One startup aid for diesel engines is to heat the intake air with fuel-fired (combusting) glow plugs. This starting aid is reliable only if the engine draws excess amounts of air through its intake manifold to supply oxygen to both the fuel fired glow plugs and a fuel charge in the combustion chamber. Otherwise, the fuel-fired glow plug can consume all the oxygen in the air and “starve” the engine.
[0006] A particular problem arises where an internal combustion engine is used to drive stationery equipment, e.g. a generator or pump. Such devices are used intermittently and may remain idle or in storage for extended periods. The devices typically are transported to a remote location and the engine must be able to start quickly and reliably without significant preparation.
[0007] It is therefore an objective of the present invention to provide a cold starting aid system and a starting method that will obviate or mitigate the above disadvantages.
SUMMARY OF THE INVENTION
[0008] In general terms, the present invention relates to a cold start system for internal combustion engines and its method of use. In one aspect of the invention, there is provided a cold start system for an engine having at least one fuel injector and an air intake manifold to supply fuel and air respectively, into a combustion chamber. The cold start system includes at least one heating element to be disposed in the air intake manifold to heat a body of air and at least one heating element to be disposed around the fuel injector to heat the fuel contained therein.
[0009] Preferably, a controller, including a series of switches, is used to regulate a supply of power from a battery to the starter, and the plurality of heating elements. The controller is connected to a microprocessor with associated power management software. The software directs the controller by way of a feed back loop connected to an ambient temperature sensor, to select an appropriate heating and cranking cycle. Additional sensors can be incorporated into the controller and include a RPM sensor which detects if the engine has started, an oil pressure sensor which monitors the pressure of the oil, a water sensor which detects if there is water present in the fuel, and a range RPM sensor which detects if the speed of the engine is outside of the normal operating range.
[0010] In a preferred embodiment, a fuel pre-heat system consists of a heater body mounted around the fuel injector. The body houses the fuel injector and a thermally conductive gasket may be positioned between the body and the fuel injector, to enhance heat transfer there between. A plurality of heating elements are inserted into a series of holes located around an exterior of the body, which minimizes the distance between the fuel pre-heat system and the combustion chamber.
[0011] An air pre-heat system of a preferred embodiment includes a spacer located in the air intake manifold and a plurality of heating elements. A series of ports are preferably located in a peripheral wall of the spacer, into which the heater elements are inserted. A thermal insulator may be positioned between the spacer and the air intake manifold. A plurality of insulating fasteners are used to mount the spacer to the air intake manifold and minimize heat transfer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] These and other features of the preferred embodiments of the invention will become more apparent in the following detailed description in which reference is made to the appended drawings wherein:
[0013] [0013]FIG. 1 is a schematic representation of an internal combustion engine including a cold starting aid system.
[0014] [0014]FIG. 2 is a plan view of a fuel heater used in the system of FIG. 1.
[0015] [0015]FIG. 3 is a section on the line A-A of FIG. 2.
[0016] [0016]FIG. 4 is a side view of an air heater.
[0017] [0017]FIG. 5 is a section on the line B-B of FIG. 4.
[0018] [0018]FIG. 6 shows details of start sequences.
[0019] [0019]FIG. 7 shows details of start sequences.
[0020] [0020]FIG. 8 shows details of start sequences.
[0021] [0021]FIG. 9 shows details of start sequences.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0022] Referring to FIG. 1, a typical air-cooled internal combustion engine 10 includes a crank case 11 , a crank shaft 12 connected to a piston 14 which is housed in a cylinder 16 , and a to combustion chamber 18 disposed between the piston 14 and cylinder 16 . An air intake manifold 24 and an exhaust manifold 26 are connected to the combustion chamber 18 . A starter 22 is connected to the crankshaft 12 . An electrical fuel pump 30 is connected by fuel lines 13 to a fuel injector 28 , which supplies the fuel 34 to the combustion chamber 18 . The fuel pump 30 is controlled by a “Fuel ON” solenoid 31 , and a “Fuel OFF” solenoid 32 , to regulate the supply of electrical power from a battery 56 to the pump 30 . The voltage supplied to the system by the battery 56 can be 12 volt DC or 24 volt DC. Incorporated in the engine 10 is a cold starting aid system 8 consisting of a fuel heater 35 distributed around the fuel injector 28 to heat the fuel 34 , and an air heater 43 positioned on the air intake manifold 24 to heat the air 33 .
[0023] The fuel heater 35 , shown in FIGS. 2 and 3, includes a heater body 38 , which is mounted onto the cylinder 16 of FIG. 1, and a recess 42 in the body 38 to encompass the body of the fuel injector 28 . A thermally conductive gasket 40 is positioned between the heater body 38 and the injector 28 to enhance the transference of heat therebetween. A plurality of heating elements 37 , which in the preferred embodiment are electric Firerod cartridges, are inserted into a plurality of corresponding holes 41 located around an exterior of the heater body 38 . These heating elements 37 are powered by the battery 56 of FIG. 1.
[0024] The air heater 43 of the preferred embodiment, shown in FIGS. 4 and 5, includes a spacer 48 and a plurality of heating elements 36 . A series of ports 44 are located in a peripheral wall 46 of the spacer 48 in a staggered orientation, into which the heater elements 36 are inserted. In the preferred embodiment, the air heating elements are electric Glow plugs that are powered by a 12 volt DC battery 56 . For systems that use 24 volt DC power, the spacer 48 is divided into a first portion 47 and a second portion 49 . An electrical insulator 51 is sandwiched between the portions 47 , 49 , of the spacer 48 , in order to separate the electrical grounds of the two portions 47 , 49 . A thermal insulator 50 is positioned between the spacer 48 and the air intake manifold 24 , to help inhibit thermal transfer to the rest of the engine 10 , which may act as a thermal heat sink. The same thermal insulator 50 acts as an electrical insulator, which electrically isolates the spacer from the air manifold 24 . A wraparound housing 80 , made of a thermally conductive material, such as aluminum, is installed on both sides of the spacer 48 in order to protect the heating elements 36 from the inclusion of foreign matter. A plurality of insulating fasteners 45 are used to mount the spacer 48 , thermal insulator 50 , and wraparound housing 80 to the air manifold 24 .
[0025] A controller 52 , including a series of switches 54 , is used to regulate the supply of power from the battery 56 to the starter 22 , the “Fuel ON” solenoid 31 , the “Fuel OFF” solenoid 32 , and the heating elements 36 . The controller 52 is connected to a microprocessor with real time clock 62 and is controlled by the associated power management software 60 . The software 60 directs the controller 52 by way of a feedback loop 57 connected to a temperature sensor 58 to select an appropriate heating and cranking cycle. The heating/cranking cycle depends of the ambient temperature read by the temperature sensor 58 . In the preferred embodiment, the temperature of the oil 9 in the crankcase 11 is monitored for an indication of ambient temperature. Additional sensors can be included to feed various signals into the controller, in order to monitor the engine operation. Examples of additional sensors include a proximity sensor 64 which detects if the engine 10 has started, an oil pressure sensor 66 which monitors the pressure of the oil 9 , a water in fuel sensor 68 which detects if there is water present in the fuel 34 , and a range RPM sensor 70 which detects if the speed of the engine 10 is outside of the normal operating range. All the run or fault states monitored by the various sensors are indicated on the controller 54 by a series of indicators 69 .
[0026] The operation of the cold starting aid system 8 in connection with the internal combustion engine 10 is directed by a series of different start up sequences 71 , 72 , 73 , 74 , 75 , 76 , 77 and 78 , given in FIGS. 6 through 9. Each of the start up sequences 71 - 78 provides a different sequence of the operation of the starter 22 , fuel pump 30 , solenoids 31 , 32 , and heating elements 36 , 37 . The sequencing logic of the power management software 60 directs the order in which the components 22 , 31 , 32 , 36 , 37 are enabled or disabled, in order to minimize the amount of power required for start up of the engine 10 . In certain instances the air 33 and the fuel 34 , either simultaneously or separately, are heated for a certain delta time unit before being delivered into the combustion chamber 18 . In other instances, the air 33 and fuel 34 are delivered into the combustion chamber 18 without the application of heat.
[0027] The power management software 60 selects which of the particular startup sequences 71 - 78 is followed, preferably based on the ambient temperature measured by the temperature sensor 58 in the oil 9 . By way of example only, an outline of the start up sequence 77 for the temperature range −32° C. to −41° C. shown in FIG. 9 is now described.
[0028] For the first six seconds the starter 22 is de-energized and the fuel pump 30 and the air and fuel heaters 35 , 43 are energized, thereby heating the air 33 situated near the spacer 48 and heating the fuel 34 deposited into the fuel injector 28 by the pump 30 , before the crankshaft 12 is rotated. After the sixth second until the end of the fifteenth second the fuel pump 30 is de-energized, the starter 22 remains de-energized, and the fuel and air heating systems 35 , 43 remain energized, thereby further heating of the air 33 near the spacer 48 and heating of the fuel 34 retained in the injector 28 . After the fifteenth second until the end of the eighteenth second the fuel pump 30 is energized, the fuel and air heating systems 35 , 43 are de-energized, and the starter 22 is energized, thereby allowing the pre-heated air 33 and the pre-heated fuel 34 to be drawn into the combustion chamber 18 as the crankshaft 12 is rotated. Further amounts of fuel 34 and air 33 supplied to the combustion chamber IS are not pre-heated. After the eighteenth second until the end of the thirtieth second all the components 30 , 35 , 43 and 22 are energized, whereby the fuel 34 and the air 33 are heated as they flow into the combustion chamber 18 , during rotation of the crankshaft 12 . If the engine 10 starts, the proximity sensor 64 detects the increase in speed and directs the controller 52 to stop the heating and cranking cycle.
[0029] If after the thirtieth second the engine 10 has not started, the fuel pump 30 and the starter 22 are de-energized while the fuel and air heating systems 35 , 43 remain energized until the thirty ninth second. These systems 35 , 43 continue to pre-heat the air 33 situated in the vicinity of the spacer 48 and the fuel 34 retained in the injector 28 , before the crankshaft 12 is further rotated. After the end of the thirty ninth second until the end of the forty fifth second the fuel pump 30 and starter 22 are energized and the fuel and air heating systems 35 , 43 are de-energized, thereby supplying the pre-heated air 33 and the pre-heated fuel 34 to the combustion chamber 18 , during crankshaft 12 rotation. Further amounts of fuel 34 and air 33 supplied to the combustion chamber 18 are not pre-heated. After the forty fifth second until the end of the sixtieth second all the components 30 , 35 , 43 , and 22 are energized, whereby the air 33 and fuel 34 supplied to the combustion chamber 18 are pre-heated as the crankshaft 12 is rotated.
[0030] The start-up sequence 77 is completed after the end of the sixtieth second, where by this point if the engine 10 has not started the sequence 77 can be repeated up to four times. The proximity sensor 64 will interrupt the start up sequence 77 , once the engine 10 has started, at any time during the ignition process. The other sensors 66 , 68 , and 70 can also interrupt the ignition process.
[0031] Different ambient temperatures will initiate different sequences as indicated by the sequences 71 - 76 and 78 where a “1” indicates an energized state and “0” indicates a de-energized state. It should be noted that sequence repetition and interruption is experienced by the other startup sequences 71 - 76 and 78 as well.
[0032] The cold starting aid system 8 can be used with 12 volt DC and 24 volt DC batteries 56 . The fuel heating elements 37 in the preferred embodiment are electric Firerod cartridge plugs and are preferably pressed into the holes 41 of the heater body 38 . The heater body 38 is made of a conductive material, such as aluminum. The casket 40 between the body 38 and injector 28 is made of a silicone based compound containing zinc oxide, such as Wakefield Engineering Thermal Joint Compound, which is typically malleable in order to fill in the space between the body 38 and injector 28 . Placement of the fuel heater 35 around the fuel injector 28 minimizes the distance between the heater 35 and the combustion chamber 18 , shown in FIG. 1. This results in heating of the fuel 34 closest to the combustion chamber 18 which inhibits the potential risk of vaporizing the fuel 34 in the fuel lines 13 , whereby vapor lock can occur. The air heating elements 36 in the preferred embodiment, are electric Glow plugs and are preferably threaded into the ports 44 of the spacer 48 . The use of non-combusting heaters 36 in the air intake 24 ensures that the air 33 is heated without depleting the oxygen in the air 33 inside the intake manifold 24 . The thermal insulator 50 , the electrical insulator 51 , and the fastener 45 are made of an insulating material such as Teflon.
[0033] During testing, the heat output of the four Fireroad cartridges used as fuel heating elements 37 to heat the fuel 34 in the vicinity of the fuel injector 28 , reached a maximum of 200 watts in less than 4 seconds. The four Glow plugs used as air heating elements 36 , for the air heater 43 , obtained a maximum heat output of 480 watts in less than 4 seconds. The amount of heat generated to heat the fuel 34 and air was adequate and enough to produce a reliable engine start in less than one minute, and a sustained operation for all ambient temperature ranges investigated.
[0034] All of the start up sequences 71 - 78 are typically of one minute in duration. These ignition processes can be repeated up to four times and are interruptible if the proximity sensor 64 detects that the engine 10 has started. The oil temperature ranges tested were 140° C. to 4° C. for sequence 71 , 4° C. to 4° C. for sequence 72 , −4° C. to −12° C. for sequence 73 , −12° C. to −18° C. for sequence 74 , −18° C. to −25° C. for sequence 75 , −25° C. to −32° C. for sequence 76 , −32° C. to 41° C. for sequence 77 , and −41° C. to −55° C. for sequence 78 . The temperature of other mediums, such as the ambient air, can also be used as input to the power management software 60 .
[0035] Although the invention has been described with reference to certain specific embodiments, various modifications thereof will be apparent to those skilled in the art without departing from the spirit and scope of the invention as outlined in the claims appended hereto. | A cold starting system and power management software consisting of an air heater system, a fuel heater system, a controller with microprocessor and related software, a series of devices comprising of switches, indicators, solenoids and sensors, is used as an aid to assist start up of air cooled combustion engines in extreme temperature environments. Both the air and fuel heater systems include electrically powered heating elements. The power management software controls the sequential operation of individual system components. | 5 |
[0001] This application claims the benefit of the Korean Patent Application No. P2006-52038, filed on Jun. 9, 2006, which is hereby incorporated by reference as if fully set forth herein.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a mechanical apparatus for washing/drying, and more particularly, to a structure for damping and absorbing vibration of a tub in a washer or dryer.
[0004] 2. Discussion of the Related Art
[0005] FIG. 1 is a structural diagram of a drum type washer according to a related art and FIG. 2 is a cross-sectional diagram of a damper of a drum type washer according to a related art.
[0006] Referring to FIG. 1 and FIG. 2 , a drum type washer consists of a washing tub 2 provided within an exterior 1 of the drum type washer, a dewatering tub 3 provided within the washing tub 2 to accommodate a laundry 6 therein, a damper 4 provided between the exterior 1 and the washing tub 2 to support and fix the washing tub 2 thereto and reduce an amplitude of vibration of the washing tub 2 , a spring 5 elastically provided to an upper space between the exterior 1 and the washing tub 2 to fix and support the washing tub 2 , and a leg 7 provided beneath the exterior 1 to support the drum type washer.
[0007] The damper 4 , as shown in FIG. 2 , consists of an outer pipe 8 assembled to an outer circumference of the washing tub 2 to have a pipe shape, an inner cylinder 9 assembled to an inner circumference of the exterior 1 to reciprocate within the outer pope 8 by the vibration of the washing tub 2 , and a lubricative member 10 provided between an inner circumferential part of the outer pipe 8 and an outer circumferential part of the inner cylinder 9 to generate a frictional force for alleviating the amplitude of the vibration of the washing tub 2 .
[0008] After the laundry 6 has been loaded in the dewatering tub 3 provided with the washing tub 2 , if a power is applied to the above-configured drum type washer, water is introduced into the washing tub. Once a prescribed quantity of the water is introduced, the dewatering tub 3 is rotated to wash the laundry 6 .
[0009] After completion of the washing of the laundry 6 , the laundry 6 is dewatered. In a transition state that a considerable force is instantly applied to the dewatering tub 3 in initiating the dewatering, the laundry 6 inclines to generate imbalance. While the imbalance is maintained, the dewatering tub 3 is rotated at high speed to perform the dewatering of the laundry 6 . So, an amplitude of vibration of the washing tub 2 increases.
[0010] Yet, in a normal status, the dewatering tub 3 is smoothly rotated to perform the dewatering of the laundry 6 , whereby the vibrational amplitude of the washing tub 2 decreases.
[0011] In order to reduce the vibrational amplitude generated from the washing tub 2 due to the imbalance attributed to the incline of the laundry 6 in the transition state for the dewatering initiation of the laundry 6 , the damper 4 is provided between the exterior 1 and the washing tub 2 of the drum type washer. So, the vibrational amplitude of the washing tub 2 can be reduced.
[0012] The vibrational amplitude of the washing tub 2 is reduced by a vertical force N between an inner circumference of the outer pipe 8 and an outer circumference of the inner cylinder 9 reciprocated within the outer cylinder 8 by the vibrational amplitude of the washing tube 2 or by a frictional force FN with the lubricative member 10 provided to increase the coefficient of friction.
[0013] Yet, the above-configured damper of the related art is hinged to both of the tub and the cabinet and has an excessively large incline angle. So, it is unable to effectively reduce or absorb the tub vibration in a lateral direction.
[0014] A damping force of the above-configured damper of the related art is about 70˜120N to minimize a displacement of transient vibration in initial dewatering. Yet, since the damping force is excessively large, it is unable to effectively reduce the vibration in entering normal dewatering in particular. So, most of the vibration is transferred to a floor on which the washer including the cabinet is installed.
[0015] In this case, if the damping force of the related art damper is reduced to decrease the transferred force of the vibration, the displacement in the transient vibration is increased to cause a problem.
[0016] To effectively reduce the vibration of the normal dewatering as well as the vibration of the initial dewatering and to minimize the displacement of the tub, a damping means having a new configuration is needed.
[0017] Besides, the damping means is applicable to a dryer, for which tub vibration needs to be reduced, as well as a washer.
[0018] A dryer is a well-known mechanical device for drying laundry and its details will be omitted in the following description.
SUMMARY OF THE INVENTION
[0019] Accordingly, the present invention is directed to a mechanical apparatus for washing/drying that substantially obviates one or more problems due to limitations and disadvantages of the related art.
[0020] An object of the present invention is to provide a washer or dryer, by which a damping means differing from a related art damper in configuration is provided to effective reduce vibration in normal dewatering as well as transient vibration in initial dewatering and minimize a displacement of a tub.
[0021] Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
[0022] To achieve these objects and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, a mechanical apparatus for washing/drying according to the present invention includes a tub accommodating water therein, a drum rotatably provided within the tub, a spring provided to elastically support the tub, and a damping means having one end rotatably connected to the tub by a hinge assembly and the other end connected to a shock-absorbing member fixed to a cabinet.
[0023] Thus, one end of the damping means is hinged to the tub, whereas the other end is connected to the fixed shock-absorbing member. When the tub vibrates horizontally or vertically, the vibration is buffered by the shock-absorbing member and damped by the damping means.
[0024] Since the related art damper is hinged to the cabinet and the tub, it is difficult to effectively restrict a lateral motion of the tub and the damping effect is insufficient.
[0025] Yet, in the present invention, since the damping means is fixed to the fixed shock-absorbing member, a lateral motion of the tub can be effectively restricted and damped. If the tub moves in a lateral direction, the damping means connected to the tub is turned centering on the other end connected to the shock-absorbing member. In doing so, the shock-absorbing member is bent to perform shock absorbing.
[0026] In the related art, since both end of the damper are rotatably hinged, it is unable to provide the shock-absorbing effect attributed to the bending action. So, it is difficult to buffer the lateral motion of the tub. Besides, the related art damper connection having the 4-pint link structure is unable to restrict the lateral motion of the tub correctly.
[0027] Preferably, the spring is provided to support an upper part of the tub. The spring is needed since it is not enough for the tub to be supported by the damping means only.
[0028] Preferably, the spring is loaded in the damping means. If the tub is supported by the damping means only, it is unable to place the tub at a correct position. So, the spring is necessary. Although the spring can be provided separate from the damping means, it can be loaded in the damping means.
[0029] Preferably, the shock-absorbing member includes a rubber bushing. And, the rubber bushing is fixed to the cabinet via a bracket. More preferably, the bracket has one end connected to a circumference of the rubber bushing and the other end fixed to the cabinet. So, the connection via the bracket provides additional shock absorbing attributed to the elastic power of the bracket.
[0030] Preferably, the rubber bushing is provided with a passing hole. And, the damping means includes an upper support part supporting a topside of the rubber bushing, a lower support part supporting a bottom side of the rubber bushing, and a connecting part inserted in the passing hole to connect the upper and lower supports parts.
[0031] More preferably, the rubber bushing is compressed and installed between the upper and lower support parts. Thus, if the rubber bushing is installed by being compressed, it is able to sustain the contacts between the rubber bushing and the support parts. And, it is also able to solve the problem of the loosened connection between the rubber bushing and the damping means.
[0032] As the rubber bushing is in a compressed state, compressive stress is applied to its inside. The compressive stress plays a role in preventing the crack generation of the rubber bushing. Weight is repeatedly applied to the rubber bushing by the tub vibration, which may cause fatigue breakage. Yet, if the rubber bushing is assembled in the compressive state, the compressive stress prevents the crack generation to extend a usable duration of the rubber bushing.
[0033] More preferably, the hinge assembly includes a hinge bracket having a fixing projection rotatably inserted in a fixing hole provided to the tub. In this case, the fixing projection is rotatable. So, the fixing projection is inserted in the fixing hole and then rotated to prevent its separation from the fixing hole.
[0034] And, the hinge bracket can include a hinge pin rotatably connecting the damping means. In this case, a rubber bushing is preferably provided between the damping means and the hinge pin.
[0035] More preferably, the hinge bracket has a separable configuration. In this case, the hinge bracket includes a first bracket and a second bracket assembled together to facilitate a connection between the damping means and the hinge pin.
[0036] For instance, the hinge pine is formed in one body of the first and second brackets. After the hinge pin has been inserted in an insertion hole provided to the damping means, the first and second brackets are assembled together to achieve the hinge connection with the damping means.
[0037] By inserting the rubber bushing between the hinge pin and the damping means and by forming the hinge pin in one body of the hinge bracket, it is able to prevent abrasion of the hinge pin. If the hinge pin abrades, the connection with the damping means is loosened to cause noise.
[0038] Preferably, the damping means includes a left damper connected to a left side of the tub in front of a weight center of the tub, a right damper connected to a right side of the tub to oppose the left damper, and a rear center damper connected to a center side of the tub in rear of the weight center of the tub.
[0039] In this case, if the spring is provided over the tub to support, it is able to omit the rear center damper. The spring hangs the tub to support and both of the left and right dampers can support the lower part of the tub.
[0040] If the spring supporting the upper part of the tub is omitted, the rear center damper is necessary. In this case, it is preferable that the spring is loaded in each of the dampers. In this case, it is preferable that the spring loaded in the rear center damper is greater than that of the rest of the dampers.
[0041] In this case, a damping force of each of the left and right dampers is preferably equal to or smaller than 20N. In the related art, the damping force of the damper is excessively large to increase the transfer force of the vibration to the cabinet from the tub.
[0042] And, each of the left and right dampers preferably inclines within 10° in a vertical direction. Moreover, the rear center damper can be vertically installed.
[0043] In another aspect of the present invention, a mechanical apparatus for washing/drying includes a cabinet, a tub provided within the cabinet to accommodate water therein, a damping means for supporting the tub by connecting the tub and the cabinet, a hinge assembly rotatably connecting the damping means to the tub, and a shock-absorbing member connecting to fix the damping means to the cabinet.
[0044] It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0045] The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principle of the invention. In the drawings:
[0046] FIG. 1 is a structural diagram of a drum type washer according to a related art;
[0047] FIG. 2 is a cross-sectional diagram of a damper shown in FIG. 1 ;
[0048] FIG. 3 and FIG. 4 are diagrams of preferred embodiments of the present invention;
[0049] FIG. 5 is a cross-sectional diagram of a damper shown in FIG. 4 ; and
[0050] FIGS. 6 to 8 are diagrams of a hinge connection of a damper.
DETAILED DESCRIPTION OF THE INVENTION
[0051] Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.
[0052] FIG. 3 shows a first preferred embodiment of the present invention.
[0053] Referring to FIG. 3 , a left spring 51 and a right spring 52 support an upper part of a tub 20 . And, a left damper 41 and a right damper 42 support a lower part of the tub 20 .
[0054] The dampers 41 and 42 are rotatably hinged to the tub 20 and connected to a base 70 of a cabinet via a shock-absorbing member. And, each of the left and right dampers 41 and 41 inclines toward a center of the tub 20 at an angle θ against a vertical direction. In the first embodiment of the present invention, the θ is 5˜10°.
[0055] FIG. 4 shows a second preferred embodiment of the present invention.
[0056] Referring to FIG. 4 , a spring 116 elastically supporting a tub 20 is loaded in a damper 41 ˜ 43 . And, the damper includes a left damper 41 , a right damper 42 , and a rear center damper 43 .
[0057] The left and right dampers 41 and 42 are placed in front of a center of the tub 20 . The springs 51 and 52 in FIG. 3 and the rear center damper 43 in FIG. 4 are provided in rear of the center of the tub 20 .
[0058] And, the rigidity of the spring 116 of the rear center damper 43 is greater than that of the spring 116 of each of the left and right dampers 41 and 42 .
[0059] Like the embodiment shown in FIG. 3 , the left and right dampers 41 and 42 of the embodiment shown in FIG. 4 are configured to incline. Yet, the rear center damper 43 is vertically installed.
[0060] FIG. 5 shows an internal configuration of the right damper 42 shown in FIG. 4 , which is identically applicable to the left damper 41 or the rear center damper 43 .
[0061] Besides, the former dampers 41 and 42 shown in FIG. 3 have the same damper configuration shown in FIG. 5 except that the spring 116 is excluded.
[0062] Referring to FIG. 5 , a damper includes a piston 115 , a piston rod 110 , a cylinder 113 accommodating the piston 115 and the piston rod 110 therein, and a spring 116 provided within the cylinder 113 to support the piston 115 .
[0063] And, a friction ring 114 is provided to a circumference of the piston 115 . So, the friction ring 114 slides up and down on an inner wall of the cylinder 113 to perform a damping action.
[0064] The piston 115 partitions an internal space of the cylinder into an upper space and a lower space. A communicating hole (not shown in the drawing) can be provided to the piston 115 to enable the upper and lower spaces to communicate with each other.
[0065] Optionally, another communicating hole (not shown in the drawing) can be provided to the cylinder 113 to enable the upper and lower spaced to communicate with an external environment.
[0066] Optionally, the internal space of the cylinder 11 can be filled with such liquid as oil and the like. Fluid such as air and the like within the internal space of the cylinder 113 performs damping and shock absorbing together with the friction ring 114 .
[0067] The piston rod 110 is guided by a guide part 112 formed of a plastic based material on the cylinder 113 .
[0068] A hole is provided to an upper part of the piston rod 110 to enable a hinge pin 134 to be inserted therein. And, a rubber bushing 111 is fitted into the hole.
[0069] Meanwhile, the damper is connected to the cabinet base 70 via a shock-absorbing member such as a rubber bushing 118 shown in FIG. 5 .
[0070] A bracket 71 is assembled to a circumference of the rubber bushing 118 and fixed to the cabinet base 70 as well.
[0071] A passing hole is formed in the rubber bushing 118 . And, a connecting part 120 of the damper is inserted in the passing hole. A topside of the rubber bushing 118 contacts with an upper support part 119 of the damper to be supported and a bottom side of the rubber bushing 118 contacts with a lower support part 118 of the damper to be supported. And, the lower and upper support parts 118 and 119 are connected to each other by the connecting part 120 .
[0072] The rubber bushing 118 is compressed and installed between the lower and upper support parts 118 and 119 .
[0073] The hinge assembly between the damper and the tub 20 is explained with reference to FIGS. 6 to 8 as follows.
[0074] First of all, the tub 20 and the damper are rotatably connected together by a hinge assembly.
[0075] In this case, the hinge assembly includes a hinge bracket 130 . The hinge bracket includes a first hinge bracket 131 and a second hinge bracket 132 assembled together by a hook locking. In particular, a half portion of a hinge pin 134 is built in one body of each of the first and second hinge brackets 131 and 132 .
[0076] And, the hinge bracket 130 is provided with a fixing projection 132 inserted in a fixing hole 21 of the tub 20 . In this case, the fixing projection 132 is rotatable.
[0077] So, after the fixing projection 132 has been inserted in the fixing hole 21 of the tub 20 , it is turned by 90° to provide the status shown in FIG. 8 . Hence, the hinge bracket 130 and the damper are prevented from being separated from the tub 20 .
[0078] In particular, a half portion of the fixing projection 132 is provided to each of the first and second hinge brackets 131 and 132 . And, the half portions of the fixing projection 132 have a hook-locking configuration.
[0079] After the hinge pin 134 has been inserted in the upper part of the piston rod 110 , the first and second hinge brackets 131 and 132 are assembled together. The fixing projection 133 is inserted in the fixing hole 21 of the tub 20 and then turned by 90° to be prevented from being separated from the tub 20 .
[0080] Preferably, a stopper is provided to the tub 20 to prevent the fixing projection 133 from being turned over 90°. More preferably, the stopper can include a projection enough to interrupt the rotation of the fixing projection 133 .
[0081] In the above-configured mechanical apparatus according to the present invention, when the drum is rotated to make the tub vibrate, the piston of the damper slides within the cylinder to perform the damping action while the rubber bushing as the shock-absorbing member buffers the bending of the damper to reduce the vibration.
[0082] Accordingly, the present invention provides the following effects or advantages.
[0083] First of all, the present invention provides a damping means having a configuration differing from that of the related art, thereby reducing vibration in normal dewatering as well as transient vibration in initial dewatering effectively. And, the present invention is able to minimize a displacement of a tub as well.
[0084] Secondly, the vibration transferred from a tub downwardly is minimized. And, vibration and noise caused to an installation place are considerably reduced. Hence, a silent operation is available.
[0085] Thirdly, the present invention prevents a walking phenomenon that a mechanical apparatus rocks or shakes in case of transient vibration.
[0086] It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the inventions. Thus, it is intended that the present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents. | A mechanical apparatus for washing/drying is disclosed. Accordingly, the present invention provides a structure for damping and absorbing vibration of a tub in a washer or dryer. The present invention includes a tub accommodating water therein, a drum rotatably provided within the tub, a spring provided to elastically support the tub, and a damping means having one end rotatably connected to the tub by a hinge assembly and the other end connected to a shock-absorbing member fixed to a cabinet. | 3 |
This is a continuation of application Ser. No. 08/056,502, filed May 3, 1993 and now abandoned.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a switched capacitor charge pump including a capacitor having a first capacitor terminal and a second capacitor terminal, a charging device coupled to the first capacitor terminal, for charging the capacitor, a discharge switch coupled to the first and the second capacitor terminal, for recurrently discharging the capacitor by the closing and opening of the discharge switch in response to a first or second value respectively, of a binary cyclic clock signal from a clock signal source.
The invention likewise relates to a sawtooth oscillator including such a switched capacitor charge pump.
2. Description of the Prior Art
A switched capacitor charge pump of this type is known from Proceedings of the IEEE, Vol. 71, No. 8, August 1983, pp. 941-965, R. Gregorian et al., "Switched-Capacitor Circuit Design", FIG. 1(b). The charging device in this paper is a switch capable of connecting the first capacitor terminal to a first voltage source which carries voltage V1. The second capacitor terminal is connected to a second voltage source which carries voltage V2. In each cycle of the clock signal the capacitor is first discharged by the discharge switch and then charged to a voltage difference V1-V2. In the cycle time interval T a charge dQ equal to C*(V1-V2) where C is the capacitance of the capacitor, is flowing. When the capacitor is being charged, the first voltage source is loaded, so that the voltage V1 and hence the charge dQ changes. The loading of the first voltage source may be reduced by a buffer stage i.e. a first operational amplifier arranged as a voltage follower. The second voltage source is usually the inverting input of a feedback second operational amplifier whose noninverting input is connected to the second voltage V2. The output of the second operational amplifier supplies a signal which is a measure for the charge dQ. The second voltage source carrying voltage V2 could be omitted by selecting this voltage to be equal to ground potential. However, in that case a supply voltage which is negative relative to ground potential will have to be available to the second operational amplifier. The realization of an accurate charge pump i.e. an arrangement supplying on its output a predetermined charge dQ in each cycle interval T thus turns out not to be of a simple kind.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a switched capacitor charge pump in which the above objections are met.
According to the invention a switched capacitor charge pump of the type mentioned in the opening paragraph is characterized, in that: the charging device includes a first current source coupled to the first capacitor terminal for supplying a first current to the capacitor, and in that the switched capacitor charge pump further includes: a reference voltage source, a comparator having a first input connected to the first capacitor terminal, having a second input connected to the reference voltage source and having an output for supplying an essentially binary comparison signal of which a first and a second value respectively, denote that the voltage on the first input is smaller and larger respectively, than the voltage on the second input, a second current source for supplying a second current, an output terminal, a current switch for passing the second current to the output terminal in response to a transition from the first value to the second value of the clock signal and for preventing the second current flowing to the output terminal in response to a transition from the first to the second value of the comparison signal.
The first current source charges the capacitor with the first current I1, while the current switch passes the second current I2 to the output. When the voltage on the capacitor is equal to the reference voltage Vref of the reference voltage source, the current switch prevents the second current I2 from reaching the output. In this manner the output presents a current pulsating in timing with the clock signal and producing a charge dQ=(I2/I1)*C*Vref in the time interval T of the clock signal. The reference voltage source is hardly loaded or not loaded at all by the comparator. A buffer is not necessary. The relation between the currents I2 and I1 may be accurately defined during design, certainly in the case of an integrated version. The first capacitor terminal may be connected to earth and the current switch may comprise a current router for which no negative supply voltage relative to earth is necessary.
The comparator and the current switch may be realized in various ways. A first embodiment of a switched capacitor charge pump according to the invention is thereto characterized, in that the comparator and the current switch comprise: a first and a second transistor arranged as a differential pair, and a third transistor, each transistor comprising a first main electrode, a second main electrode and a control electrode, the first main electrodes of the first and second transistors being coupled to the second current source, the control electrodes of the first and second transistors to the first capacitor terminal and the reference voltage source respectively, the second main electrode of the second transistor to a first terminal for producing a fixed potential, the second main electrode of the first transistor to the output terminal, and the first main electrode, the second main electrode and the control electrode of the third transistor being coupled to the second main electrode of the first transistor, a second terminal for producing a fixed potential, and the clock signal source respectively.
The differential pair combines the functions of comparator and current switch. Consequently, the charge pump is not only very simple but also very fast. When the second transistor takes over the second current from the first transistor, the current switch function is not performed stepwise, but in a gradual manner. However, this is no objection. Viewed over a period of time T the charge dQ remains the same. The third transistor passes the current through the first transistor to the second terminal with a fixed potential during discharging of the capacitor by the discharge switch. If the charge pump is used for charging a further capacitor, this further capacitor would be discharged by the third transistor. This may be avoided by a second embodiment of a switched capacitor charge pump according to the invention, in which the output is coupled to the second main electrode of the first transistor across a diode. The diode prevents the further capacitor from being discharged. The same effect may be realized with a third embodiment of a switched capacitor charge pump according to the invention, characterized in that the comparator and the current switch comprise: a first and a second transistor arranged as a differential pair, and a third transistor, each transistor having a first main electrode, a second main electrode and a control electrode, the first main electrodes of the first and second transistors being coupled to the second current source, the control electrodes of the first and second transistors to the first capacitor terminal and the reference voltage source respectively, the second main electrode of the second transistor to a first terminal for producing a fixed potential, the second main electrode of the first transistor to the first main electrode of the third transistor, and the second main electrode and the control electrode of the third transistor being coupled to the output terminal and the clock signal source respectively.
The third transistor is now combined in series with the first transistor, so that any discharging of a further capacitor is avoided.
The switched capacitor charge pump according to the invention may now be used for all kinds of purposes. Capacitors can be charged with this charge pump by relatively small charge portions without the use of current sources that carry absolutely small current values. For that matter, in the above formula for dQ only the relation between the second current I2 to the first current I1 plays a role. The mean value of the output current of the charge pump may be determined by the selection of the ratio I2/I1, the time interval T and thus also the frequency f=1/T of the clock signal, the capacitance C of the capacitor and/or the value Vref of the reference voltage. Long time-constants may thus be realized, for example, in control loops for voltage-controlled oscillators.
The switched capacitor charge pump is pre-eminently suitable for use in a sawtooth oscillator which comprises: a capacitor having a first capacitor terminal and a second capacitor terminal, a first transistor arranged as a current source, a main conduction path thereof being coupled to the first capacitor terminal for charging the capacitor, a first discharge transistor including a first and a second main electrode which are coupled to the second and the first capacitor terminal respectively, and including a control electrode connected for receiving a binary cyclic clock signal for recurrently discharging the capacitor by rendering the first discharge transistor conductive and nonconductive in response to a first or second value respectively, of the clock signal, and a device for generating the clock signal in response to a voltage across the capacitor.
Sawtooth oscillators of this type are used, for example, in timer circuits. The device for generating the clock signal may in practice be arranged in various ways but they always include a comparator which compares the voltage across the capacitor with the reference voltage and generates a discharge signal the moment the reference voltage is reached. By switching over the reference voltage or using an additional comparator (window comparator) and a second reference voltage, the circuit becomes self-oscillating. The oscillation frequency is then determined, for example, by the period of time necessary for charging the capacitor to the reference voltage by the first transistor. Even if the capacitor as such has an accurate value, for example, because it is connected as a discrete component to a furthermore integrated sawtooth oscillator, the parasitic capacitance on the first capacitor terminal will still be a source of inaccuracy; certainly so if the external capacitor is to have a relatively small value. The parasitic capacitance Cpar is determined by the dimensions and properties of specifically the first transistor arranged as a current source and the Miller capacitance of the first discharge transistor. Furthermore, the wiring capacitance and the input capacitance of the comparator which is connected to the first capacitor terminal play a role. As a result, the frequency of the known sawtooth oscillator is not entirely fixed due to design and process tolerances.
The consequences may now be reduced according to the invention in that the sawtooth oscillator further includes: a second transistor of similar type to the first transistor, including a main current path with a blocked current transfer, a second discharge transistor of similar type to the first discharge transistor, including a second main electrode coupled in a node to the main current path of the second transistor, and including a first main electrode and a control electrode which are connected to the first main electrode and the control electrode respectively, of the first discharge transistor, a first current source coupled to the node, for producing a first current, a reference voltage source, a comparator having a first input connected to the node, a second input connected to the reference voltage source and having an output for supplying an essentially binary comparison signal of which a first or second value respectively, denotes that the voltage on the first input is smaller and larger respectively than the voltage on the second input, a second current source for supplying a second current, for a current switch for passing the second current to the first capacitor terminal in response to a transition from the first value to the second value of the clock signal and for preventing the second current flowing to the first capacitor terminal in response to a transition from the first to the second value of the comparison signal.
The second transistor and the second discharge transistor are a copy of the first transistor and the first discharge transistor respectively, so that the parasitic capacitance on the node is substantially equally as large as the parasitic capacitance on the first capacitor terminal. The second transistor is arranged in such a way that no current flows through it and that it functions as a dummy. The second transistor and the second discharge transistor, together with the first current source, the reference current source, the comparator, the second current source and the current switch, form a charge pump which compensates with a substantially equally large compensation charge for the charge that would disappear into the parasitic capacitance Cpar. The effect of the parasitic capacitance Cpar is thereby substantially eliminated. The charge pump components connected to the node, more specifically, the second transistor and the second discharge transistor, may also be scaled versions of the corresponding components of the sawtooth oscillator. As a result, the parasitic capacitance on the node is reduced by a specific scaling factor, but this may be compensated for by an adjusted ratio of the second current I2 to the first current I1. The effect of the input capacitance of the comparator on the means for generating the clock signal may be removed by selecting for the charge pump a comparator that has an about equally large input capacitance.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other aspects of the invention will be described and explained with reference to the annexed drawing, in which:
FIG. 1 shows a functional block diagram of a switched capacitor charge pump according to the invention,
FIG. 2 shows signal diagrams in explanation of the operation of the switched capacitor charge pump shown in FIG. 1,
FIG. 3 and FIG. 4 show embodiments of a switched capacitor charge pump according to the invention,
FIG. 5, FIG. 6 and FIG. 7 show details of alternative versions of the embodiment shown in FIG. 4, and
FIG. 8 shows a sawtooth oscillator comprising a switched capacitor charge pump according to the invention.
In these drawing Figures components or elements having like function or connotation are denoted by like reference characters.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 shows the block diagram of a charge pump according to the invention. A number of signals whose signal shapes are represented in FIG. 2 occur in the charge pump. A first capacitor terminal 2 of a capacitor 4 is connected to a first current source 6 which charges the capacitor 4 with a first current I1, causing the capacitor voltage Vc across the capacitor 4 to increase with time. The second capacitor terminal 8 is connected to ground. The first capacitor terminal 2 is connected to a first input 10 of a comparator 12, a second input 14 of which is connected to a reference voltage source 16 which supplies a reference voltage Vref relative to ground. The comparator 12 has an output 18 for supplying a binary comparison signal Vcomp which adopts a low or high value respectively, if the capacitor voltage Vc on the first input 10 is smaller or larger respectively, than the reference voltage Vref on the second input 14. The capacitor 4 is periodically discharged by way of a discharge switch 20 connected to the first capacitor terminal 2 and the second capacitor terminal 8. The discharge switch 20 is controlled by a clock signal CS from a clock signal source 22, wherein a high or low value, respectively, of the clock signal CS closes or opens, respectively, the discharge switch. A current switch 24 includes a current input 26, an output terminal 28 for supplying an output current Iout and a first control input 30 and a second control input 32, to which are applied the comparison signal Vcomp and the clock signal CS respectively. The current input 26 is connected to a second current source 34 which applies a second current I2 to the current switch 24.
The current switch 24 passes the second current I2 to the output terminal 28 after a descending edge of the clock signal CS, that is to say, after the moment the capacitor 4 begins to be recharged by the first current source 6. The output current Iout then has the value I2. The current switch 24 blocks the current supply to the output terminal 28 in the case of an ascending edge of the comparison signal Vcomp, that is to say, when the capacitor voltage Vc exceeds the reference voltage Vref. The output current Iout then drops to zero again. This drop may be abrupt or gradual; the current Iout is to have dropped at any rate to zero with the next descending edge of the clock signal CS. The time elapsing between two descending edges in the clock signal CS is the clock period T. From the descending edge in the clock signal CS to the ascending edge in the comparison signal Vcomp a current I1 flows to the capacitor 4, while the capacitor voltage Vc increases to Vref. The charge dQ in the capacitor 4 is then equal to C*Vref, where C is the capacitance of the capacitor 4. During this period of time the output current Iout is proportional to the first current I1, because the following holds in that case: Iout=I2=(I2/I1)*I1. Over each clock period T the output current Iout therefore represents a charge portion dQ equal to: dQ=C*Vref*(I2/I1).
The drop of the output current Iout from the value I2 to zero may also present a gradual behaviour. If this behaviour is symmetrical around the ascending edge of the comparison signal Vcomp, it does not affect the magnitude of the charge portion dQ, because the integral of the output current Iout is not changed by it over the entire clock period T.
FIG. 3 shows a first embodiment of the charge pump. The first current source 6 and the second current source 34 from the block diagram of FIG. 1 are arranged here as a PMOS transistor 36 and a PMOS transistor 38 arranged as current sources and, together with a PMOS transistor 40 arranged as a diode, form a current mirror circuit. The sources of the PMOS transistors 36, 38 and 40 are connected to a positive supply terminal 42 and the gates of these transistors as well as the drain of PMOS transistor 40 are connected to a bias current source 44 which produces a current Ib. By scaling the PMOS transistors 36, 38 and 40, the mutual relation between the current I1 flowing through PMOS transistor 36 and I2 flowing through PMOS transistor 38 can be determined. The drain of the PMOS transistor 36 is connected to the first capacitor terminal 2 of the capacitor 4, whose second capacitor terminal 8 is connected to ground. The discharge switch 20 from the block diagram shown in FIG. 1 is arranged as an NMOS transistor 46, whose source, drain and gate are connected to the second capacitor terminal 8, the first capacitor terminal 2 and the clock signal source 22 respectively, for receiving the clock signal CS. The charge pump further includes a reference voltage source 16 and a comparator 12 which are arranged similarly to those shown in FIG. 1. The current switch 24 shown in FIG. 1 comprises the PMOS transistors 48 and 50 and the NMOS transistor 52. The sources of the PMOS transistors 48 and 50 are connected to the drain of PMOS transistor 38. The gate of PMOS transistor 48 is connected to the output 18 of the comparator 12. The gate of PMOS transistor 50 is connected to the output 18 via an inverter 54, so that only one of either of the two PMOS transistors 48 and 50 is conducting. The drain of the PMOS transistor 48 is connected to the output 28 and the drain of the PMOS transistor 50 is connected to ground. The source, drain and gate of the NMOS transistor 52 are connected to ground, the drain of PMOS transistor 48 and the clock signal generator 22 respectively, to receive the clock signal CS. As appears from FIG. 2, the comparison signal Vcomp becomes low while capacitor 4 is being discharged, so that the current I2 is passed to the output terminal 28 by PMOS transistor 48. The NMOS transistor 52, however, short-circuits the current supply to ground when capacitor 4 is being discharged. This achieves that the current Iout in the output terminal 28 adopts the shape as represented in FIG. 2.
The embodiment of the charge pump shown in FIG. 3 may be simplified by letting the PMOS transistors 48 and 50 operate both as a comparator and as a current switch. The result is represented in FIG. 4. The gate of the PMOS transistor 48 is now directly connected to the first capacitor terminal 2 and the gate of the PMOS transistor 40 is directly connected to the reference voltage source 16. A capacitor 56 charged with charge portions dQ by the charge pump is connected to the output 28 by way of example. In that case a diode 58 prevents the capacitor 56 from being discharged unintentionally by the NMOS transistor 52. Once the capacitor 56 has been charged, it may be discharged again as desired by way of charge portions dQ. This is provided by the NMOS transistors 60, 62 and 64 and the selector switch 66. The NMOS transistors 62 and 64 are arranged as a current mirror, while the drain of NMOS transistor 64, which operates as an output of the current minor, is connected to the output terminal 28. The drain of NMOS transistor 62, which operates as an input of the current minor, is connected to the drain of the PMOS transistor 48 via the main current path of the NMOS transistor 60. The gate of the NMOS transistor 60 can be connected, by way of the selector switch 66, to ground (position a) or to the positive supply terminal 42 (position b). In position b the NMOS transistor 60 is conducting and the current I2 flows through the current minor to the output terminal 28, so that the capacitor 56 is discharged. In position a the current minor is inoperative and the capacitor 56 is charged.
FIG. 5 shows a first variant of the circuit of FIG. 4, in which the drain of the PMOS transistor 48 is connected to the output terminal 28 by way of the main current path of a PMOS transistor 68. The gate of the PMOS transistor 68 is connected to the clock signal CS, so that this transistor operates as a serial switch blocking the current supply to the output terminal 28 when the capacitor 4 is being discharged.
FIG. 6 shows a second variant of the circuit shown in FIG. 4. The blocking of the current supply to the output terminal 28 is now realized by use of an NMOS transistor 70, whose source, drain and gate are connected to earth, the drain of PMOS transistor 38 and the clock signal CS respectively.
FIG. 7 shows a third variant of the circuit of FIG. 4. The blocking of the current supply to the output terminal 28 is realized here by use of a PMOS transistor 72, whose source, drain and gate are connected to the drain of PMOS transistor 38, the sources of the PMOS transistors 48 and 50 and the clock signal CS respectively. Furthermore, there is shown that the current Iout may be tapped by way of a current mirror 74 as desired.
FIG. 8 shows a sawtooth oscillator in which the charge pump is used. The actual sawtooth oscillator is of a prior-art type and includes a PMOS transistor 80 arranged as a current source, a capacitor 82 which includes a first capacitor terminal 84 and a second capacitor terminal 86, an NMOS transistor 88 for discharging the capacitor 82, a reference voltage source 90 and a clock signal generator 92 which generates a clock signal CS. The clock signal generator 92 includes a comparator 94 comparing the voltage on the first capacitor terminal 84 with the reference voltage Vref of the reference voltage source 90. The comparator 94 triggers a one-shot generator 96 whose output signal functions as the clock signal. In lieu of the comparator 94 and the one-shot generator 96 alternatively a window comparator may be used in known fashion. The source and drain of the PMOS transistor 80 are connected to the first capacitor terminal 84 and the positive supply terminal 42 respectively. The gate of the PMOS transistor 80 may be supplied with a voltage in a similar manner to the one shown for the PMOS transistor 36 in FIG. 3. The second capacitor terminal 86 is connected to ground. The drain, source and gate of the NMOS transistor 88 are connected to the second capacitor terminal 86, the first capacitor terminal 84 and the clock signal CS respectively, of the clock signal generator 92. The clock period T and thus also the frequency of the sawtooth oscillator are determined, for example, by the period of time necessary for charging the capacitor 82 up to the reference voltage level Vref. The charge current Ich of the PMOS transistor 80 arranged as a current source flows not only to the capacitor 82 but also partly to a parasitic capacitor 98 present on the first capacitor terminal 84. The clock period T will thus be longer than could be expected. This effect is the more obvious when the capacitance of the parasitic capacitor 98 can no longer be discarded relative to the capacitance of the capacitor 82. The parasitic capacitance is formed, among other things, by the output capacitance of the PMOS transistor 80, the Miller capacitance of the NMOS transistor 88 and the wiring capacitance.
The charge pump includes the NMOS transistor 46, the first current source 6, the comparator 12, the second current source 34 and the current switch 24 which are connected between earth and the positive supply terminal 42 in similar manner to the one shown in FIGS. 1 and 3. The output terminal 28 is connected to the first capacitor terminal 84. The NMOS transistor 46 is connected in a node 100 to the first current source 6, the first input 10 of the comparator 12 and to the drain of a PMOS transistor 102 whose source and gate are connected to the positive supply terminal 42. The PMOS transistor 102 is a copy of the PMOS transistor 80, but does not supply current to the node 100. The NMOS transistor 46 is a copy of the NMOS transistor 88. The capacitance of the parasitic capacitor 104 on the node 100 is then substantially equal to the capacitance of the parasitic capacitor 98 on the first capacitor terminal 84. The parasitic capacitor 98 is charged up to the reference voltage level Vref. By using the same reference voltage in the charge pump, the parasitic capacitor 104 will have a same charge as the parasitic capacitor 98. By leading the current Iout to the first capacitor terminal 84, the charge which would otherwise flow into the parasitic capacitor 98 will be compensated for the charge pump. In this manner the influence of the parasitic capacitor is strongly reduced.
The charge pump may be realized by the embodiments already shown and discussed. When the charge pump shown in FIG. 4 is used, the diode 58 and the transistors 60, 62 and 64 are redundant. So is the NMOS transistor 52, because the NMOS transistor 88 carries out the same function. When the charge pump shown in FIG. 6 is used, the diode 58 will be redundant.
By selecting the comparators 94 and 12 of the same type, the mutual equality of the parasitic capacitors 98 and 104 is even further increased and so is the accuracy with which the influence of the parasitic capacitor 98 is reduced. The NMOS transistor 46 and the PMOS transistor 102 may also be scaled versions of the corresponding transistors 88 and 80. The same is possible with the comparators 94 and 12. The attendant capacitance reduction of the parasitic capacitor 104 may be adjusted by selecting an appropriate relation between the currents I2 and I1.
The invention is not restricted to the embodiments shown. In lieu of or in combination with the unipolar transistors shown, also bipolar transistors may be used, the emitter, collector and base then substituting for the source, drain and gate. | Charge pump including: a capacitor (4) which includes a first capacitor terminal (2) and a second capacitor terminal (8), a discharge switch (20) for discharging the capacitor (4) by the closing and opening of the discharge switch (20) in response to a first or second value respectively, of a clock signal (CS), a first current source (6) for supplying a first current (I1) to the first capacitor terminal (2), a comparator (12) whose first input (10) is connected to the first capacitor terminal (2) and whose second input (14) is connected to a reference voltage source (16) and which comparator generates a comparison signal (Vcomp) of which a first or second value denotes that the voltage (Vc) on the first input (10) is smaller or larger than the voltage on the second input (14), a current switch (24) passing a second current (I2) coming from the second current source (34) to an output terminal (28) once the clock signal (CS) has changed from the first to the second value, and prevents the second current (I2) flowing to the output terminal (28) once the comparison signal (Vcomp) has changed from the first to the second value. A sawtooth oscillator is formed by using the charge pump as a timing circuit with the oscillator providing the clock signal, and the second current from the output terminal being fed back to the first capacitor terminal. | 7 |
CROSS REFERENCE TO RELATED APPLICATION
This application claims the benefit of U.S. Provisional Application 60/703,208, filed Jul. 28, 2005.
TECHNICAL FIELD
The present invention relates generally to torque converters, and more specifically, to novel vehicular torque converters having turbine and impeller assemblies that employ more economic, integrated structural features for fluid coupling and increased torque capacity.
BACKGROUND OF THE INVENTION
Torque converters are positioned between the engine and transmission case of motorized vehicles. They play an important role by controlling on/off power from the engine to the rest of the drive train. In addition, they provide torque multiplication, dampen engine vibration and assure smooth start-ups and speed changes.
A typical torque converter assembly comprises as principal components, an impeller or pump, a turbine and a stator positioned between the turbine and pump. The turbine and pump are seated in opposing shells and rotate therewith. The torque converter pump is connected to the engine, and as the pump rotates energy is transmitted to the turbine by forcing fluid against turbine blades causing their rotation. The turbine, which is connected to the transmission, transmits torque to vehicle wheels. The torque converter pump also turns the transmission oil pump. The stator positioned between the turbine and impeller operates to redirect the flow of fluid allowing the pump to rotate with less torque, so as to provide torque multiplication.
Heretofore, when larger torque capacities were required, the usual practice was to increase the size of the torque converter. This however, has resulted in economic tradeoffs. Also contributing to overall higher costs has been the industry practice of manufacturing core assemblies for torque converters as multiple separate components requiring additional manufacturing steps.
While the foregoing practices have been effective in meeting needs for torque converters with greater torque capacities, there still remains an unfulfilled need for a solution to the problem of increasing torque capacity and overall values of torque converter performance, but with fewer significant economic trade-offs.
SUMMARY OF THE INVENTION
Accordingly, it has now been found that torque converter capacity can be increased more economically by fabricating converter turbine cores as integrated assemblies. That is to say, instead of fabricating torque converter blades and cores as independent structures, the two structures are integrated during the manufacturing process eliminating one or more fabrication steps, for example. The integration of blades and cores simplifies the assembling process for enhanced cost savings. Integration also eliminates the need for multiple sets of forming dies, normally required. Importantly, integration, while achieving improved economics, it is also capable of increasing torque capacity by inducing fluid coupling. Other advantages of the novel integrated turbine/impeller assemblies include a more robust design for greater strength and durability.
It is therefore one principal object of the invention to provide novel integrated torque converter blade and core assemblies comprising a generally crescent shaped blade body having an outer convex edge, and an inner concave edge. The integrated structure includes a truncated core portion engaged with the inner concave edge of the blade body to form an “integrated torque converter blade-core segment”. The latter expression is generic, and intended to include both integrated turbine blade-core segments and integrated impeller or pump blade-core segments.
It is yet a further object of the invention to provide integrated torque converter assemblies, wherein the turbine, for example, possesses structural features for inducing fluid coupling. The core portion of a converter blade is generally incurved or concave shaped forming a void or space filled with transmission fluid. Such space in conventional turbine and impeller cores is normally unused, or otherwise wasted space. These inventors, however, discovered the capacity of a torque converter can be increased by inducing fluid coupling in this otherwise structurally “empty” space.
Thus, it is still a further principal object of the invention to provide the truncated core interior of the integrated torque converter blade segment with structural means, such as a baffle or barrier member suitable for inducing fluid coupling. Baffles and barriers, for example that induce fluid coupling and concomitant increased torque capacity may even be integral with the truncated core portion of the converter blade segment.
Importantly, the shape or configuration of the barrier or baffle member may be any design or curved shape that provides overall efficient fluid coupling performance in the core interior. The particular configuration of the fluid coupling element presented in the drawings is but one representative example of a suitable baffle design.
It is yet a further principal object of the invention to provide a torque converter turbine, wherein a plurality of adjacent integrated torque converter blade-core segments, as previously discussed, are adjoined through their truncated cores to form integrated turbine-core assemblies. That is, unlike conventional turbine-core assemblies wherein individual blades with tabs are installed onto prefabricated cores having slotted openings for receiving the tabs of torque converter blades, the integrated torque converter blade segments of this invention are adjoined to adjacent segments through their truncated cores to form fully integrated turbine blade-core assemblies, as well as integrated impeller blade-core assemblies. Thus, the integrated turbine core assemblies, and pump core assemblies of this invention achieve further cost advantages by eliminating conventional independent slotted torque converter cores for mounting tabbed turbine and impeller blades.
While the foregoing objects, features and advantages of the invention have been described mainly in connection with increasing torque capacity of turbines, this is for purposes of convenience only. And, it is to be understood the same objects, features and advantages apply equally to impellers for torque converters for increasing pump capacities as well.
It is still a further principal object of the invention to provide for novel torque converters per se, generally for use whenever extra torque capacity is required in motorized vehicles. The invention is especially well adapted for use in motor vehicles when start-up torque ratio is a not a premium requisite for a given vehicle.
The torque converters of the invention are characterized by at least an integrated turbine-core assembly and integrated impeller-core assembly for increased torque capacities. The turbine core assembly and the impeller core assembly each comprise a plurality of the integrated torque converter blade-core segments. As previously pointed out, the segments have a generally crescent shaped blade body with an outer convex edge, an inner concave edge and a truncated core engaged with the inner concave edge of the blade body. A plurality of adjacent integrated blade segments adjoined through their truncated cores form the integrated turbine-core and integrated impeller-core assemblies. The innovative torque converters comprising the integrated turbines and impellers of the invention include means for effecting fluid coupling for increased torque capacity, such as through rigid tabs of suitable design which perform as barriers or baffles for inducing fluid coupling in the interior region of their respective cores.
As part of the torque converters of the invention, including the integrated torque converter blade segments assembled into turbines and impellers, they are equipped with slotted shells for seating the integrated and assembled turbines and impellers into unitized components for use in torque converters of the invention, especially when requiring higher torque capacities. The integrated, higher capacity torque converters of the invention are suitable for use with most all vehicular transmissions, including, but not limited to automotive applications, but also commercial vehicles including buses, trucks, military vehicles, and the like.
These and other features and advantages will become more apparent from a reading of the detailed description below.
BRIEF DESCRIPTION OF THE DRAWINGS
The nature and mode of operation of the present invention will now be more fully described in the following detailed description of the invention taken with the accompanying drawing figures, in which:
FIG. 1 of the drawings is a frontal view of a conventional torque converter blade assembly illustrating a continuous, empty, non-integrated core, blade design associated with the prior art;
FIG. 2 of the drawings is a backside view of the non-integrated torque converter blade assembly of FIG. 1 .
FIG. 3 of the drawings is an isometric view of a torque converter blade employed in the non-integrated core assemblies of FIGS. 1 and 2 , illustrating the tabs for engaging with slots of a torque converter core.
FIG. 4 is an isometric backside view of a representative integrated torque converter blade-core segment, either turbine or impeller, of the invention with an end plate or tab member as means for inducing fluid coupling for increased torque capacity;
FIG. 5 is a frontal view illustrating a partially assembled turbine comprising integrated torque converter blade segments of the invention arranged in overlapped format wherein each segment is nestled against and brazed to the adjacent blade segment for uniform spacing in an early stage of turbine fabrication, and further illustrating core development from segmented structures with internal tabs as baffles for fluid coupling.
FIG. 6 is a backside view of a plurality of the integrated converter blade segments of the invention with overlapped truncated core segments engaged and bonded to one another in an early stage fabrication of a torque converter turbine;
FIG. 7 is a frontal, isometric view of an integrated torque converter turbine assembly of the invention mounted in a converter shell;
FIG. 8 is a backside view of the assembly of FIG. 7 ;
FIG. 9 is an isometric view of a torque converter of the invention with increased torque capacity shown in an exploded format to illustrate the main components of the device; and,
FIG. 10 is an elevated side sectional view of an assembled torque converter equipped with the integrated turbine and impeller assemblies of the invention also illustrating the fluid coupling means in the core area.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Turning first to FIGS. 1-3 , illustrated are conventional, non-integrated turbine assemblies 10 for torque converters, frontal and rear views, FIGS. 1 and 2 , respectively, and an enlarged blade 14 ( FIG. 3 ) employed in the turbines of FIGS. 1-2 . FIG. 1 illustrates in the frontal view of this non-integrated turbine a core 12 , which is a continuous incurved or concaved ring. The interior of the incurved ring while filled with fluid is devoid of obstructions or structural discontinuities. Core 12 , however, contains a series of slots (not shown) for receiving mounting tabs 16 of turbine blade 14 . Such state-of-the-art nonintegrated turbine assemblies 10 , while generally reliable, lack the improved structural features for effectuating the desired fluid coupling for increasing torque converter capacity economically like that of the instant invention.
The fundamental building-block of the instant invention is illustrated beginning with FIG. 4 , which is a back view of an integrated turbine blade-core segment 18 . Segment 18 is comprised of blade portion 20 and core portion 22 . Segments 18 may be fabricated using methods familiar among ordinary skilled artisans, wherein, for example, an integral one-piece blade-core structure is fabricated, or alternatively, blade and core fabricated as separate components and brazed or welded into one-piece structures in a sequence of steps.
Blade 20 is generally crescent or crescentic in shape, or in other words, possesses the appearance of a moon-like fractional phase with a generally rounded outer convex edge 24 and an inner inwardly curved or concave edge 26 . Blade portion 20 is also preferably rounded or bowed generally along its longitudinal axis, as best illustrated by FIG. 6 , and comprises one or more, usually dual tabs 28 for affixing to a turbine shell.
It will be observed that core portion 22 is preferably tiered into two or more layers 30 - 32 in a stepped pattern, wherein margin 34 performs as a demarcation between the upper tier portion 30 and lower tier 32 . Margin 34 is especially useful by aiding in the assembly process of the turbine, wherein individual integrated blade-core segments are conveniently overlapped with the next adjacent segment whereby the truncated core portion of the next adjacent segment is butted-up against margin 34 prior to brazing, for example, for uniform spacing between turbine blade-core segments, as best illustrated by FIGS. 5-6 .
The integrated turbine blade-core segments 18 preferably include at least one fluid coupling element 36 , which is capable of coupling with transmission fluid for increasing torque capacity. Preferably, element 36 consists of any suitable rigid structure forged as an integral or nonintegral tab positioned principally in the inwardly curved region of the core. Representative examples include a functional baffle, rounded tab, wall, partition, screen member, or separator of suitable design, to name but a few. Fluid coupling element 36 can be integral with the truncated core or affixed to the core during fabrication. Usually, each core segment of the integrated turbine blade-core may have at least one fluid coupling element 36 . However, the invention contemplates integrated turbines wherein not each and every truncated blade-core segment is necessarily equipped with a fluid coupling element 36 .
FIG. 5 illustrates a frontal view of a plurality of integrated torque converter blade-core segments 38 nestled together with each segment 40 , 42 and 44 having a fluid coupling element 36 . In this featured embodiment, the fluid coupling element is rounded on the bottom-edge 46 to conform with the generally rounded pattern of the turbine core.
As previously discussed, FIG. 6 consists of a plurality of integrated torque converter blade-core segments with tabs 28 for mounting to a turbine shell (See FIG. 8 ). In addition, the turbine blades 20 are preferably bowed along their longitudinal axes.
FIG. 7 a frontal view of an assembled integrated torque converter turbine 48 of the invention positioned in turbine shell 50 , (the latter illustrated in greater detail in FIG. 8 with tab slots 51 ) before tabs 28 are rolled (folded). Each torque converter blade segment comprises a bowed blade 20 , wherein the core segments converge into an essentially seamless continuous structure 52 with each segment having an elevated fluid coupling tab 36 in the interior region of the incurved core.
FIG. 9 provides an exploded view of a torque converter 54 with torque converter turbine assembly 48 , torque converter impeller assembly 56 and stator 58 . The impeller assembly 56 is shown in perspective for a better view of impeller 53 seated in shell 51 .
Finally, FIG. 10 provides a sectional, side elevational view of torque converter 54 of the instant invention comprising the integrated torque converter turbine 48 and impeller 56 assemblies of the invention having turbine blades/impeller blades 20 with fluid coupling tabs 36 in the core region. | More efficient, economic vehicular torque converters comprising novel integrated one-piece turbine/impeller blade-core assemblies with innovative fluid coupling means for greater torque capacities. | 5 |
BACKGROUND OF THE INVENTION
[0001] The present invention relates generally to the manufacture of automotive engine components possessing non-round exterior shapes using a powder metallurgy process, and more particularly to the manufacture of camshaft lobes using a modified dynamic magnetic compaction (DMC) process.
[0002] Automotive engine camshaft lobes must endure significant and repeated mechanical loading under high-speed, high-temperature and tribologically-varying conditions. The use of conventional manufacturing processes, such as casting, forging or the like, tends to produce components which, while satisfactory from a load-bearing perspective, result in heavy, inefficient structures. Likewise, the use of conventional manufacturing approaches is not conducive to tailoring a particular material's desirable properties to discreet locations on a camshaft lobe. Furthermore, the use of DMC, which is taught in U.S. Pat. Nos. 5,405,574, 5,611,139, 5,611,230 and 5,689,797 (all of which are hereby incorporated by reference), while a valuable way to compact both metallic and non-metallic powders to achieve high-density components, has not hitherto been extended to camshaft lobes, gears or other non-axisymmetric (i.e., non-cylindrical) or otherwise irregularly-shaped components.
[0003] Camshaft lobes and other highly-loaded engine components could benefit from the strategic placement of materials into the lobe that can be tailored to the lobe operating environment. For example, surface portions (for example, the generally planar eccentric surfaces) of the lobe that are exposed to higher loads may benefit from harder or other more load-bearing materials that would not be needed in the generally axisymmetric portion of the lobe. Likewise, such materials could be used in the DMC process to give a particular shape to a formed component. Because such more robust materials may involve greater expense, weight or detrimental features, they may only be used sparingly. As such, it would be advantageous to develop ways to combine the efficient manufacturing attributes of DMC with the tailored structural properties of disparate constituent materials to fabricate structurally efficient components.
BRIEF SUMMARY OF THE INVENTION
[0004] These advantages can be achieved by the present invention, wherein improved engine components and methods of making such components are disclosed. According to a first aspect of the invention, a method of fabricating an automotive engine component using DMC is disclosed. Under the present method, an exterior profile of the component can be made non-axisymmetric (i.e., such that its external shape deviates from a cylindrical form). The method includes providing a die or related tool with an interior profile that is substantially similar to the exterior profile of the component being formed. Furthermore, a first material in powder form is placed within a first part of the die interior profile such that the first material defines at least a first portion of the component being formed. In addition, the method includes placing within a second part of the die interior profile a second material, and then forming the automotive engine component using dynamic magnetic compaction to compact or otherwise densify the two materials together. In the present context, the term “substantially” refers to an arrangement of elements or features that, while in theory would be expected to exhibit exact correspondence or behavior, may, in practice embody something slightly less than exact. As such, the term denotes the degree by which a quantitative value, measurement or other related representation may vary from a stated reference without resulting in a change in the basic function of the subject matter at issue.
[0005] In one form, the second material is placed within the region that defines the non-axisymmetric exterior profile, while the first material is placed in the region that defines the axisymmetric exterior profile, non-axisymmetric profile or both. In a more specific form, the first powder can be used to form a majority of the component, with the second material being placed in a location such that upon formation of the component, the second material occupies a portion of the surface of the component that can be expected to be exposed to increased load, wear or related mechanical requirements. In one optional form, the method further includes making the automotive component into a camshaft lobe. In another option, the second material comprises a second powder, which in a more particular optional form, may possess different wear, friction or related tribological properties from the powder of the first material. In an even more particular form, the second powder is harder or otherwise more wear-resistant than the first powder. In another option, at least one of the first and second powders are selected from the group consisting of metal powders, ceramic powders and a combination of both.
[0006] In another option, instead of a powder, the second material may be in the form of a substantially rigid insert. Such insert may be made from a different material from the alloy used to make up the remainder of the component. In one form, the different material may be a hardenable steel alloy, ceramic material or other long-wearing, high load-bearing composition. Such an insert defines a profile such that can be placed over at least a portion of the first material such that the second material forms an outer surface of a part of the component that is expected to be exposed to higher levels of load, wear, friction or the like. For example, in situations where the component includes an eccentricity or related non-axisymmetric shape and such non-axisymmetric shape corresponds to the part of the component in need of additional structural properties, the second material can be placed in such a way that it makes up at least a majority of the non-axisymmetric exterior profile, or takes a majority of the loading when the load is at a maximum. The substantially rigid insert may be made from either a reusable or non-reusable. In the case of the latter, the insert may remain with the formed component upon completion of the compaction. In the case of the former, such as when being used to shape the outer profile of the component of interest, the insert does not remain with the automotive engine component upon the fabrication such that it may be re-used. In one configuration, during the forming process, the one or more substantially rigid insert cooperates with one or more reusable inserts such that an outer shape of the component is defined by such cooperation. In a more particular form, numerous such reusable segments can be placed within a die so that their inner surfaces compact the first and second materials in response to the DMC process. In this way, the reusable segments can press the non-reusable segments into place in a particular location in the component to be formed.
[0007] According to another aspect of the invention, a method of fabricating a camshaft lobe is disclosed. The method includes providing a die with an interior profile that substantially defines an exterior surface of the lobe, placing a first material within a first part of the interior profile of the die, placing a second material within a second part of the interior profile of the die such that the second material is used to form at least a portion of the exterior surface of the lobe that corresponds to the lobe eccentricity, and forming the lobe using dynamic magnetic compaction. As with the previous aspect, one significant advantage over the prior art DMC process is that non-axisymmetric and related irregular component shapes can be formed.
[0008] Optionally, the second material occupies a majority of the exterior surface of the lobe that corresponds to the lobe eccentricity. In this way, the use of materials with tribologically superior properties can be tailored to corresponding surface regions of the lobe. This can be an advantageous way of supplementing the tribological or related structural properties of heavily-loaded parts of the lobe, such as its eccentric region, where conventional DMC may not be capable of producing a part with the necessary structural attributes. In another option, at least one of the first and second materials is made of a powder that can be compacted via the DMC process. In a further option, the second material can be made from a different composition than the first material. In this way, metal alloys, ceramic precursors or related materials can be strategically placed on portions of the exterior surface of the lobe to tailor the material properties to the load-bearing needs of the lobe. In yet another option, the second material is made from a substantially rigid non-reusable insert that may be operated upon by a reusable insert. The interior profile of the die used to form the lobe may be made up of reusable inserts that cooperate with the one or more non-reusable inserts so that the second material that makes up the non-reusable insert is pressed together with the first material. In this way, the lobe is formed as a substantially unitary structure that can be further processed.
[0009] According to yet another aspect of the invention, a camshaft lobe for an internal combustion engine is disclosed. The lobe can be made by the DMC process discussed in the previous aspects, and includes a camshaft-engagable interior surface made up of a first material and an exterior surface made up of one or more eccentric portions at least a portion of which is formed by a second material. In this way, the interior surface defines an axial bore thought the lobe.
[0010] Optionally, the first material is made from different than the second material. In a more specific option, both the first and second materials comprises a powder such that each is tailored to particular portions of the lobe. In another option, the second material can be made from a substantially rigid insert selected from the group consisting of reusable inserts and non-reusable inserts. In the case of re-usable inserts, the second material is used to form a portion of the finished lobe, but does not remain with it. In the case of non-reusable inserts, the second material, by virtue of the DMC process, is formed into at least a portion of the lobe exterior surface and remains with it. In this way, the second material can (in the case of a re-usable insert) help to define the shape during DMC or (in the case of a non-reusable insert) be used to actually occupy a portion of the lobe exterior surface once co-formed with the first material during DMC.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0011] The following detailed description of the present invention can be best understood when read in conjunction with the following drawings, where like structure is indicated with like reference numerals and in which:
[0012] FIGS. 1A through 1C shows a the various steps used in the DMC process of the prior art for making a cylindrical-shaped powder component;
[0013] FIG. 2 shows a top-down view of a cylindrical part and the various parts used to form such part using a conventional DMC process of the prior art;
[0014] FIG. 3 shows a cutaway view of a camshaft lobe and associated tooling of the modified DMC process according to an aspect of the present invention;
[0015] FIG. 4 shows a cutaway view of a camshaft lobe and associated tooling of the modified DMC process according to another aspect of the present invention;
[0016] FIG. 5 shows a camshaft lobe as produced by the tooling of FIG. 3 ; and
[0017] FIG. 6 shows a partial cutaway view of an automotive engine with a camshaft employing one or more lobes made by the modified DMC process of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0018] Referring initially to FIGS. 1A through 1C , the DMC process according to the prior art is shown, where a generally cylindrical-shaped component is produced. FIG. 1A shows a powder material 10 placed within an electrically conductive cylindrical armature 20 . A coil 30 is connected to a direct current power supply (not shown) such that electric current can be passed through the coil 30 . The powder material 10 substantially fills the electrically conductive armature 20 (also called a sleeve). Referring with particularity to FIG. 1B , a large quantity of electrical current 40 is made to flow through the coil 30 ; this current induces a magnetic field 50 in a normal direction that in turn sets up magnetic pressure pulse 60 that is applied to the electrically conductive container 20 . This radially inward pressure acts to compress the container 20 , causing the powder material 10 to become compacted and densified into a full density parts in a very brief amount of time (for example, less than one second) and at relatively low temperatures. In addition, this operation can (if necessary) be performed in a controlled environment to avoid contaminating the consolidated material. By way of example, the current flow through the coil 30 may be in the order of 100,000 amperes at a voltage of about 4,000 volts, although it will be appreciated that other values of current and voltage may be employed, depending on the characteristics of the container 20 and the powder material 10 inside. Referring with particularity to FIG. 1C , once the DMC process is complete, the armature 20 and powder material 10 are shown compressed, occupying a smaller transverse dimension than previous size of FIG. 1A .
[0019] Referring next to FIG. 2 , a top-down view of a notional cylindrical DMC containment structure according to the prior art is shown. A loosely held powder 10 is placed in an electrically conductive round container 20 . The sudden passage of a large amount of current through the coil 30 produces a magnetic field, which in turn induces a current in the container 20 . This induced current produces a second magnetic field which, by its magnitude and direction, repels the first magnetic field. This mutual repulsion causes container 20 to be compressed, which in turn applies pressure on the powder 10 , causing its compaction. A top-down view of a notional cylindrical DMC containment structure is shown. Coil 30 is placed inside an external containment shell 70 to restrain the coil 30 against radially-outward expansion when repelled by the second magnetic field.
[0020] Referring next to FIGS. 3 and 4 , camshaft lobes 110 ( FIG. 3) and 210 ( FIG. 4 ) are shown, as well tooling used to form them. The use of non-axisymmetric tooling results in a modified DMC process in that the axisymmetric limits of the traditional DMC process have been overcome. Referring with particularity to FIG. 3 , an electrically-conducting coil 130 is wound around a sleeve 125 that is placed between the coil 130 and die 120 . As shown, a gap (for example, and air gap) 135 is situated between coil 130 and sleeve 125 . As with conventional DMC, the present DMC-based process exploits the electric current flowing through coil 130 in order to impart a magnetically-compressive force onto the sleeve 125 , die 120 and the precursor materials within. The die 120 is generally axisymmetrically-shaped around its outer surface 121 , while its inner surface 122 is similar to the desired outer shape of the lobe 110 being formed. The die 120 is formed from four reusable segments 120 A, 120 B, 120 C and 120 D, where the portion of the inner surface 122 that is used to form the axisymmetric part of the lobe 110 corresponds to die segments 120 A and 120 B and the portion of the inner surface 122 that is used to form the non-axisymmetric eccentric part of the lobe 110 corresponds to die segments 120 C and 120 D. A central bore 101 can be formed in the lobe 110 through the inclusion of an appropriately-shaped mandrel (not shown) during the lobe-forming process. Sleeve 125 is compressed by the magnetic forces generated by coil 130 , as is die 120 ; this in turn causes the precursor materials to be deformed by the compressive forces to compact the precursor powder materials. This results in formation of a “green” or un-sintered lobe 110 that may undergo conventional sintering, machining and related finishing steps (none of which are shown).
[0021] As can be seen in the figure, lobe 110 has at least two distinct portions 110 A and 110 B. The first portion 110 A forms a base circle portion of lobe 110 and is preferably made from a material such as an alloy steel powder possessive of mechanical properties suitable for camshaft lobe applications. In addition to occupying the substantial entirety of the axisymmetric portion of the lobe 110 , the first portion 110 A can form the underlying (i.e., interior) surface of the non-axisymmetric part, and a first material can be used to define or otherwise occupy this first portion 111 A. By contrast, a second material can be used for the second portion 110 B where additional structural (including tribological) properties may be desired. Unlike the first portion 111 A, the second portion 110 B is preferably limited to parts of the lobe 110 that require the enhanced properties associated with the second material. As with the first material, the second material may be a metal powder specifically formulated to meet the specific needs for an application where the lobe surface would experience at least one of rolling loads, sliding loads or a combination thereof. In one example, the powder may be made from a ferrous alloy with chemical composition formulated in a way so as to improve wear resistance, friction reduction or the like of the second material. Because the second material is tailored to meet particular performance needs, and is typically at least one of more expensive, heavier or more difficult to fabricate with, it should be used sparingly. As such, it may be advantageous to only have it occupy as much surface area of lobe 110 as necessary. By having this structurally-enhanced second material occupy the outer surface of portion 110 B of lobe 110 , it can, with subsequent compaction with the first material of the first portion 110 A by DMC, form lobe 110 into a substantially unitary structure with composite properties: a low-cost, lightweight, readily manufacturable first portion 110 A and a durable, tribologically-enhanced second portion 110 B.
[0022] Referring with particularity to FIG. 4 , lobe 210 can be formed by the operation of the die 220 , coil 230 and sleeve 225 . Lobe 210 can define a slightly different shape than that of lobe 110 , including a reduced use of a second material in first portion 210 A in a region that makes room for an insert in the form of second portion 210 B. Unlike the lobe 110 of FIG. 3 , the first portion 210 A may have an exposed outer surface in the non-axisymmetric portion of the lobe 210 . As with the lobe 110 of FIG. 3 , a first material may be used to occupy the first portion 210 A. Also, as with the lobe 110 , lobe 210 includes discrete locations on the outer surface of the second portion 210 B where a second material insert can be used to enhance local structural properties. Also as with the device of FIG. 3 , the die 220 with inner and outer surfaces 222 , 221 can be segmented into reusable segments 220 A, 220 B, 220 C and 220 D and include the shaped cutouts on the inner surface 222 thereof to promote ease of component assembly. Also as with the configuration depicted in FIG. 3 , a gap 235 may be formed between the coil 230 and the die 220 .
[0023] Unlike the assembly of FIG. 3 , the second material used for the second portion 210 B of lobe 210 is in the form of an insert that cooperates with the first material such that upon compaction by the DMC process, forms indentations into the lobe 210 that define the second portion 210 B. In one form, the second portion insert 210 B can be a material (for example, in powder form) that has tribologically different properties than the material making up the first portion 210 A of lobe 210 . Together, the inserts made up of lobe inserts 210 B and die 220 (including its segments 220 A, 220 B, 220 C and 220 D) take on one of two forms. In the first form, inserts in the form of die segments 220 A, 220 B, 220 C and 220 D are reusable, while in the second, the inserts 210 B are non-reusable in that they become a part of the finished lobe 210 , and the two forms can cooperate with one another to form lobe 210 . Die segments 220 A and 220 D are placed such that upon compaction, the non-reusable inserts fill the indents that are formed in the outer surface of the second portion 210 B of lobe 210 that, in addition to being used to help create a desired lobe profile, remain with the lobe 210 upon completion of the compaction process, thereby forming an integral part of the outer surface thereof by occupying the second portion 210 B. As such, it is designed to couple with the powder first material precursor to form a composite lobe 210 in a manner generally similar to that of lobe 110 . Placement of the non-reusable insert (made of, for example, the second material) into the precursor may be simpler than in the case of lobe 110 , where both the first and second materials are in powder form. To facilitate the process (where a dual powder filling operation is employed), a temporary screen (not shown) may be used to keep fill powders in the desired regions until compaction. Appropriate heat treatment may be performed on the compacted lobes. As with the previous aspect of lobe 110 , once DMC has been completed, various additional sintering, machining and related finishing steps may be undertaken.
[0024] Referring next to FIGS. 5 and 6 , an as-manufactured lobe 1100 and incorporation into a camshaft 1150 and automotive engine 1000 is shown. Referring with particularity to FIG. 5 , the two portions 1100 A and 1100 B of lobe 1100 are shown co-formed by the DMC process. As will be understood from the above discussion, first portion 1110 A is generally made up of the first material that occupies the substantial entirety of the axisymmetric part 1110 . Second portion 1110 B is generally made up of the structurally-enhanced second material that occupies the substantial entirety of the non-axisymmetric part 1120 . The central bore 1001 that is used to connect the lobe 1100 to a camshaft 1150 (shown in FIG. 6 ) may be of any appropriate size.
[0025] Referring with particularity to FIG. 6 , portions of the top of an automotive engine 1000 incorporating a lobe 1100 and accompanying camshaft 1150 is shown for a notional direct-acting tappet design. A piston 1300 reciprocates within a cylinder in the engine block (not shown). A cylinder head 1200 includes intake ports 1240 and exhaust ports 1250 with corresponding intake and exhaust valves 1400 , 1500 to convey the incoming air and spent combustion byproducts, respectively that are produced by a combustion process taking place between the piston 1300 and a spark plug (not shown) in the cylinder. Camshaft 1150 is driven from an external source, such as a crankshaft (not shown), and includes a cam lobe 1100 that defines a non-axisymmetric profile about the longitudinal axis of the camshaft 1150 . Upon camshaft 1150 rotation about its longitudinal axis, the eccentric portion of the lobe 1100 selectively overcomes a bias in valve spring 1600 to force exhaust valve 1500 at the appropriate time. It will be appreciated that similar structure is included for the intake valve 1400 , but is removed from the present drawing for clarity. The lobe 1100 of the present invention includes selective reinforcement in the eccentric portion as discussed above to promote enhanced durability and performance. It will be appreciated by those skilled in the art that the valve train architecture shown associated with engine 1000 , which includes a direct-acting tappet, is merely representative, and that camshaft lobes manufactured using the modified DMC process as described herein are equally applicable to other valve train architectures (not shown).
[0026] While certain representative embodiments and details have been shown for purposes of illustrating the invention, it will be apparent to those skilled in the art that various changes may be made without departing from the scope of the invention, which is defined in the appended claims. | An automotive engine component and method of producing the same. The method uses dynamic magnetic compaction to form components with non-axisymmetric and related irregular shapes. A die is used that has an interior profile that is substantially similar to the non-axisymmetric exterior of the component to be formed such that first and second materials can be placed into the die prior to compaction. The first material is in powder form and can be placed in the die to make up a first portion of the component being formed, while a second material can be placed in the die to make up a second portion of the component. The second material, which may possess different tribological properties from those of the first material, can be arranged in the die so that upon formation, at least a portion of the component's non-axisymmetric exterior profile is shaped by or includes the second material. | 8 |
REFERENCE TO RELATED APPLICATION
This application claims the benefit of provisional application No. 60/609,105, filed Sep. 10, 2004 the disclosure of which is incorporated herein by reference.
FIELD OF THE INVENTION
The present invention is directed to a collection apparatus and methods for use of the collection apparatus. The present invention relates to liquid handling devices and more particularly to fraction collectors. The devices of the present invention may be used for chromatographic separations, sample purifications, and more particularly, for high throughput purification of samples from a chemical library.
BACKGROUND
Fraction collectors are well-known devices intended for collecting liquid samples originating from slow-flowing sources having variable liquid compositions. Fraction collectors are typically used in chromatographic separations such as high performance liquid chromatography (HPLC), gas chromatography (GC), supercritical fluid chromatography (SFC), column chromatography, and liquid-liquid separations, and for the collection of distillates from various distillation processes. The size of each individual sample or fraction dispensed by the fraction collector is determined by conventional measuring equipment such as a timer, a drop counter, a level sensing device, or by a variety of spectrophotometric methods. Fraction collectors typically sequentially align a dispensing head, carry a sample delivery conduit or tube over individual collection vessels part of an array of collection vessels, and deliver sample to collection vessels.
Fraction collectors may be broadly categorized into two groups. The first group includes fraction collectors in which a plurality of collection vessels are mounted on a generally circular turntable. These fraction collectors are commonly called “turntable collectors.” The turntable collectors all generally operate to fill a plurality of collection vessels by the combination of a rotatably mounted turntable and a rotatably mounted arm carrying a dispensing head. The dispensing head is typically aligned over a single collection vessel, the liquid is dispensed into the collection vessel, and the turntable then rotates to align with another collection vessel. In turntable collectors, the plurality of collection vessels are typically arranged in a concentric circular or spiral pattern. In order to manipulate the dispensing head over collection vessels in different circles of a concentric pattern or with an expanding or contracting spiral pattern, the rotatably mounted arm moves to align the dispensing head with each of the individual collection vessels in the arrangement.
The second group of fraction collectors includes collectors with the collection vessels arranged in a grid pattern on a stationary stage, and a dispensing head manipulated in either a 2-dimensional plane or in all three dimensions to selectively dispense liquid into the individual collection vessels. Fraction collectors in the second group are commonly called “X-Y collectors.”
The two groups of fraction collectors each have distinct advantages. For example, when handling a large number of liquid collection vessels, fraction collectors with rectangular grid patterns more effectively use bench space. X-Y collectors are also better suited to handling large scale collection vessels than are the rotatably mounted turntables. Furthermore, X-Y collectors may be adapted to popular standardized receptacle plates, such as microtiter plates, or other standard or custom arrangements. In contrast, turntable-type fraction collectors may be more advantageous when used in high resolution liquid chromatography as they require shorter attachment tubing between the slow-flowing source and the dispensing head, thus limiting diffusional re-mixing of the separated components within the liquid flow and resulting in better separation.
Both X-Y and turntable fraction collectors must be adjusted to fit the collection vessels used for sample collection, which commonly come in various sizes. Generally, vertical adjustment of the fraction collector has typically been done by either manual adjustment of the legs or incorporation of a vertical adjustment (Z-axis) of the dispensing head. The first method, utilized in some X-Y collectors, allows for manual adjustment of the height of the dispensing head by removing the legs of the base of the fraction collector and putting on longer or shorter legs as desired. However, while this method can be effective, if the legs of the base are adjusted manually, the racks containing the collection vessels need to be removed during adjustment, as the legs can only be adjusted individually. Furthermore, it is difficult to balance the collection bed during the adjustment, creating the opportunity for spillage to occur. Moreover, manual adjustment requires realignment of the dispensing head with the collection vessels and collection bed, introducing additional steps that could damage the fraction collection apparatus. As fraction collectors have become more advanced, the tolerances have become tighter, and therefore manual adjustment of the dispensing head assembly threatens to damage some of the fragile electrical parts.
In addition, manual vertical dispensing head adjustment may knock the dispensing head out of horizontal alignment, causing the liquid fractions to miss the sample collection vessels. This can result in lost time in cleaning up the liquid, damage to the instrument, or present a hazardous environment for the operator, depending on the contents of the liquid. Furthermore, when a dispensing assembly is knocked out of alignment, the precision alignment procedures required to realign the assembly can be very time consuming.
Incorporation of a vertical adjustment (Z-axis) axis into the dispensing head is known in the art. However, fraction collectors with a Z-axis require complex mechanics, and sometimes software, in order to get the dispensing head to move reliably and precisely in all three directions. These complex mechanics often add both size and cost. Furthermore, because collection vessels used in a single fraction collection run are commonly of uniform size, a dispensing head that moves in a vertical direction is often unnecessary.
Regardless of whether the fraction collector is an X-Y collector or a turntable collector, it is of primary importance in the design that the mechanism for aligning the dispensing head and collection vessels be as simple and as sturdy as possible, while being reliably capable of precisely positioning the dispensing head over sequential collection vessel. Although many fraction collectors known in the art can reliably and precisely position the dispensing head over a sequential collection vessel, many are quite complex and therefore not only expensive but difficult to adjust and maintain. In particular, known fraction collector arrangements may include dispensing head adjustment mechanisms that are extremely complicated and delicate.
Therefore, a need exists for a fraction collector that reliably and precisely aligns a dispensing head and collection vessel without adding significant cost or fragility.
SUMMARY OF THE INVENTION
This invention relates to a new device for adjusting the distance between the dispensing head and the collection vessel on a fraction collector. More specifically, this invention relates to a bed on a fraction collector that can be adjusted without adjusting the legs of the fraction collector. Because the bed of the fraction collector can be adjusted, there is no need for a Z-axis on the dispensing head.
In one embodiment, the invention provides for a fraction collector that includes a support system, a carriage movably supported by the support system, an extension arm attached to the carriage, a dispensing head moveably attached to the extension arm, wherein the dispensing head and carriage can move along the support system in a first plane, and a collection bed moveably connected to the support system wherein the collection bed may be moved in a second plane perpendicular to the first plane without adjusting the support system.
In certain embodiments, the invention may comprise a method for using the fraction collector by determining a proper displacement of the collection bed from the dispensing head, aligning the collection bed with the support system at the proper displacement, and stably attaching the collection bed to the support system.
In one embodiment of the present invention, the fraction collector includes a support system, a carriage including an extension arm with a dispensing head connected to the support system, wherein the dispensing head and carriage move together in a single plane, and a collection bed connected to the support system such that the collection bed is adjustable in a direction perpendicular to the single plane. In this embodiment, the support system for the fraction collector comprises left and right legs with leg bases and a front and top brace. Generally the support system supports both the carriage and the collection bed. In some embodiments, the single plane is an X-Y plane level with and parallel to a support surface such as a bench or table and the direction perpendicular to the single plain is the Z direction. Typically, the collection bed will be capable of holding collection vessels of various sizes and shapes with or without a system of racks.
In another aspect of the invention, the collection bed of the fraction collector is made of a tray having two side edges and front and rear edges. Attached to the collection bed are collection bed arms which extend to attach the collection bed to the support system. In one embodiment of the invention, the support system has a series of pegs in the right and left legs and the collection bed arms have anchor points spaced in a complementary fashion to the pegs in the legs of the support system. The collection bed may be vertically adjusted by raising or lowering the collection bed and locking the collection bed in place on the support system through the pegs and anchor points on the collection bed arm. In alternative embodiments, the anchor points on the collection bed may be slots or holes and the pegs in the legs may be fixed or removable.
In another embodiment, the collection bed may be vertically adjusted by raising or lowering the collection bed and locking the collection bed in place on the support system through a series of peg holes in the right and left legs, and anchor holes on the collection bed arms such that removable pegs may be inserted through the anchoring holes and into the peg holes to secure the collection bed in place.
In still another embodiment, the collection bed arms are angularly disposed from the tray of the collection bed by an angle, such that when the tray is tipped back the whole collection bed is vertically adjustable. In this and other related embodiments, the right and left legs of the support system may have grooves or notches for retaining the vertical adjustment of the collection bed. Furthermore, in certain embodiments, the rear edge of the collection bed tray may be shaped to fit into the grooves or notches, or the rear edge of the collection bed tray may have an attached complementary shape to the grooves or notches such that the complementary shape precisely fits into the groove or notch.
In yet another aspect of the invention, the right and left legs of the fraction collector support system may have exterior or interior channels capable of holding the collection bed at a level orientation when the collection bed arms are inserted into them.
Other embodiments of the invention may include a fraction collector for dispensing liquid from a dispensing head into collection vessels carried on a collection bed, the fraction collector includes a support system, a carriage including an extension arm with a dispensing head connected to the support system, wherein the dispensing head and carriage move together in a single plane, and a collection bed connected to the support system such that the collection bed is adjustable by way of lift movement.
In other contemplated embodiments of the invention, the collection bed may not be attached to the apparatus and instead may rest upon or fully integrate a stage that can be raised or lowered manually, via hydraulic methods, or with a motorized screw mechanism. In such embodiments, the collection bed needs will be reliably and precisely aligned with the dispensing head on the apparatus using markings on the fraction collector and collection bed, positioning lasers on the apparatus, and/or markings on both the fraction collector and support on which the fraction collector rests, such as a laboratory bench.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a fraction collector demonstrating the use of pegs on the legs of the fraction collector.
FIG. 2 is a perspective view of a fraction collector demonstrating the use of peg holes in the legs of the fraction collector.
FIG. 3 is a perspective view of a fraction collector demonstrating the use of exterior channels in the legs of a fraction collector.
FIG. 4 a perspective view of a fraction collector demonstrating the use of interior channels in the legs of a fraction collector.
FIG. 5 is a perspective view of an alternative style collection bed.
FIG. 6 is a perspective view of a mechanized style collection bed.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
As illustrated by the embodiment of FIG. 1 , the fraction collector device 100 comprises a vertically adjustable collection bed 101 in a given position under a dispensing head 150 . As one of skill in the art will understand, this given position may be in any of a range of positions. As a non-limiting example, the given positions may be appropriate for racks containing collection vessels of known size. In other embodiments, the given position may be adjustable along a continuum allowing the use of custom collection vessels. The dispensing head 150 is moveably mounted on an extension arm 160 that is in turn moveably mounted on a carriage 170 . In the embodiment demonstrated by FIG. 1 , the dispensing head 150 is capable of movement along the extension arm 160 in a Y-direction, and the extension arm 160 is capable of movement in an X-direction. The skilled artisan understands that the X and Y directions are arbitrarily assigned and not meant to be limiting. Embodiments where the dispensing head 150 moves in the X-direction and the extension arm 160 moves in the Y-direction are anticipated.
The fraction collector 100 , as shown in FIG. 1 , is supported by a left leg 180 , a left leg base 200 , a right leg 190 , and a right leg base 210 . As will be understood by one skilled in the art, the bases of the legs may be any shape adequate to stabilize the legs. Although a certain shape of base is demonstrated in the figures, the base is not meant to be so limiting. The two legs are connected by a top brace 220 and a front brace 230 . Although the embodiment of FIG. 1 demonstrates the top brace 220 and front brace 230 as permanently connecting the two legs, further embodiments anticipate the top brace 220 and the front brace 230 as removably connected to the two legs, such as through the use of screws. Additional embodiments contemplate the front brace extending to the support surface. In some embodiments, the legs, leg bases, and braces will form a support system for the fraction collector. In still other embodiments, it is contemplated that the support system will not include a front brace.
The carriage 170 is mounted behind the front brace 230 by one of a number of methods well known to those of ordinary skill in the art. The collection bed 101 has a tray area 102 where the racks 240 are situated, as shown, or where individual collection vessels may be arranged using a system other than the rack system. The collection bed 101 further has two collection bed arms 110 , that extend from the tray area of the collection bed 101 , and provide attachment of the collection bed to the left 180 and right leg 190 . The collection bed arms 110 allow for vertical height adjustment of the collection bed 101 .
A number of specific devices for attaching the collection bed are contemplated as demonstrated by FIGS. 1 , 2 , and 3 . In FIG. 1 , both the left leg 180 and the right leg 190 have a series of front pegs 140 and rear pegs 145 . As shown, all of the pegs are in fixed positions, however the skilled artisan will appreciate that the pegs may also be moveable. FIG. 1 shows the collection bed arms as having front anchoring points 120 and rear anchoring points 130 . The collection bed 101 is attached to the left leg 180 and right leg 190 by engaging the front anchoring points 120 with the front pegs 140 and the rear anchoring points 130 with the rear pegs 145 . The front pegs 140 and the rear pegs 145 are situated on the left leg 180 and right leg 190 such that the collection bed 101 is level when all the anchoring points are engaged by the corresponding pegs.
In the embodiment of FIG. 1 , vertical adjustment of the collection bed 101 is made by manually disengaging the anchoring points 120 , 130 and moving the collection bed up or down, depending on the desired location, and then reengaging the anchoring points 120 , 130 with the pegs 140 , 145 at the new location.
The embodiment of FIG. 2 demonstrates another way of attaching the collection bed 101 to the legs 180 , 190 of the fraction collector 100 . FIG. 2 shows the collection bed arm 110 as having front 125 and rear 135 anchoring holes, while the left leg 180 and right leg 190 have front 142 and rear 148 peg holes. The peg holes and anchoring holes are positioned such that the front anchoring holes 125 will align with the front peg holes 142 and the rear anchoring holes 135 will align with the rear peg holes 148 when the collection bed 101 is level. When the anchoring holes and peg holes are aligned, movable pegs 141 may be inserted to fix the collection bed 101 to the legs. Although the embodiment demonstrates peg holes and pegs cylindrical in shape, one skilled in the art will understand that the pegs may be any shape, including squares, rectangles, semi-circles and the like. In alternative embodiments, pins will be placed through the anchoring holes and peg holes to fix the collection bed 101 to the legs.
FIG. 3 demonstrates yet another embodiment of the present invention. In FIG. 3 , left leg 180 and right leg 190 of the fraction collector have mounted exterior channels 250 . In certain embodiments, the exterior channels 250 will not be mounted, but will be an integral part of the legs. In the embodiment of FIG. 3 , the collection bed arms 110 are inserted into the exterior channels 250 in order to hold the collection bed in a fixed position. The exterior channels 250 are positioned on the legs, at various heights, such that the collection bed 101 will be level when attached to the fraction collector 100 . Numerous channel sizes and spacings may be envisioned by one of ordinary skill in the art in order to achieve a greater or lesser range of height adjustment for the collection bed 101 . For example, the exterior channels 250 may be arranged according to collection vessels currently known to exist in the art. It is not an object of this invention to be limited by the illustrated scale of the positions or number of positions shown in the figures.
The embodiment of FIG. 4 shows an arrangement similar to that in FIG. 3 . FIG. 4 demonstrates interior channels 260 recessed into the left and right legs 180 , 190 of the fraction collector 100 . In this case, the collection bed arms 110 are inserted into the interior channels 260 . The interior channels 260 are positioned on the legs, at various heights, such that the collection bed 101 will be level when attached to the fraction collector 100 . Once again, the positioning of the interior channels are not meant to be limiting. Furthermore, the skilled artisan will understand that although the exterior channels demonstrated in FIG. 3 and the interior channels demonstrated in FIG. 4 are shown on perpendicular sides of the legs, the channels may be on any side of the leg, as long as the collection bed arms are adapted. In some embodiments, the interior channel will extend through the leg. In other embodiments, the interior channels may be on a parallel side of the leg. If the interior channels are on a parallel side of the leg, the collection bed arm will need to include at least one projection for connection.
Although FIGS. 1-3 demonstrate attachment of the collection bed arm 110 on the outside side of the leg, it is also contemplated that the locus of attachment using any of the above-mentioned attachment devices could be also on the inward facing portion of the legs. Moreover, one of skill in the art will understand that different styles of legs may be used in place of legs 180 , 190 . In certain embodiments, the legs may encompass legs with grooves, as well as legs having other styles. In some embodiments, both edges of the leg will have cutouts or other types of notches. In other embodiments, only one side of the leg will have grooves or notches. The skilled artisan will understand that the number, size and side of the attachment devices are not meant to be limited by the illustrated scale of the positions or number of positions shown in the figures.
FIG. 5 shows an embodiment of an alternate style of collection bed assembly 300 . In the embodiment of FIG. 5 , the leg of the support system includes grooves or notches 280 , that are able to receive a rod 330 . A rear edge 290 of the collection bed 300 may rest against legs 180 , 190 possibly in grooves or notches to further support the collection bed 101 . As in FIG. 5 , the collection bed arms 320 are angularly disposed from the plane of the collection bed. The arms 320 can either be attached by the rod 330 as shown in FIG. 5 , looped, or a rod may only partially extend from one leg to the other. As one of skill in the art understands the extension of the rod may vary in alternative embodiments. The rod can either be short or long while still keeping within the spirit of the invention.
In the embodiment of FIG. 5 , the alternate style collection bed 300 is vertically adjusted by raising the front portion of bed 300 enough to free the rear edge 290 from the legs 180 , 190 and to release the rod 330 from the grooves 280 and then sliding the collection bed 300 up and down the legs to the desired position. In addition to the grooves 280 as shown in FIG. 5 , other embodiments are envisioned. For example, a series of notches that receive a complementarily shaped portion of the rear edge of the collection bed tray is contemplated. Furthermore, the notches could also be locks designed to accept a complementarily shaped key.
Mechanized embodiments of the invention are contemplated. For example, the fraction collector may include a collection bed with a hydraulic lift. As demonstrated by FIG. 6 , the fraction collector 500 may comprise a collection bed 510 with a screw-driven lift 520 . The screw-driven lift 520 may include a screw 530 and an expandable lattice 540 . Although the embodiment shown in FIG. 6 demonstrates two screw driven lifts, the skilled artisan will understand that any number of lifts, as long as they can function with a fraction collector, may be used. It is contemplated that embodiments comprising a hydraulic lift or a screw-driven lift may be motorized with either an automatically driven system or a manually driven system. In the mechanized embodiments, the collection bed may not be attached to the fraction collector. Instead, the collection bed may rest upon or fully integrate with a stage that can be raised or lowered manually, via hydraulic methods, or with a motorized screw mechanism. In such embodiments, the collection bed needs to be reliably and precisely aligned with the dispensing head on the apparatus. Precise alignment could be carried out via markings on the apparatus and collection bed, positioning lasers on the apparatus, and/or with markings on both the apparatus and support on which the apparatus rests, such as a bench. Because mechanized versions add a layer of complexity to the vertically adjustable collection bed, and may be impractical in certain situations and because mechanized versions utilize mechanics well understood by the skilled artisan, these embodiments will not be further described.
While embodiments of the foregoing invention have been described in some detail and by way of illustration and example to provide clarity and understanding, it should be understood that certain changes and modifications can be made therein in accordance with ordinary skill in the art without departing from the invention in its broader aspects as defined in the following claims. | A fraction collector comprising a movable tray is provided. The movable tray may be attached to the fraction collector support system in a variety of ways and adjusted without adjusting the parts of the fraction collector support system. The moveable tray may be stably attached to the fraction collector support system by either fixed or removable pegs, as well as by channels. | 1 |
BACKGROUND OF THE INVENTION
This invention relates to a method of identifying piston rings having an asymmetrical cross section such as taper face rings, scraper rings or bevelled edged rings. The method comprises the application of a marking which extends from an annular face (flank face) of the piston ring to a circumferential face thereof.
For identifying piston rings, particularly piston rings having a non-cylindrical running face, so-called "top" markings have been stamped on the annular faces of the piston ring adjacent the piston ring gap to ensure a proper positioning of the piston ring when installed in the engine. While the piston rings have the "top" marking on that annular face which is to be oriented towards the combustion chamber, it occurs quite frequently that individual rings, in the course of further machining, stacking or packaging are accidentally inverted so they are positioned in an inverted state in the piston ring stack. Since in general the piston rings are no longer drawn onto the piston manually (this operation has largely been taken over by machines) the installer has to rely fully on the piston ring manufacturer concerning the correct positioning of the piston rings in the packages. Piston rings drawn onto the piston in an inverted position not only affect adversely the operation of the engine, but later necessitate a time-consuming disassembly thereof. Although with significant labor and thus with the substantial cost the above-descirbed error can conceivably be detected during the final inspection of the piston rings, such individual checking is otherwise only seldom justified and furthermore, the possibility of oversight by the inspectors (due to carelessness or fatigue) cannot be discounted.
German Pat. No. 1,251,114 discloses piston rings having a circumferential groove which is provided in the running face of the piston ring for mechanically sensing the position of the piston rings. This type of marking, however, is expensive to provide: markings on the running faces of the piston rings must not exceed a certain thickness since the surface quality of the running faces has to meet very high standards. If a marking of substantial depth is provided, its sealing function in the engine may be adversely affected.
Further, according to German Utility Model (Gebrauchsmuster) No. 7,039,835, each piston ring is provided with a notch which extends from one of the annular faces to one of the circumferential faces of the piston ring. It is a disadvantage of such an arrangement that the notch can only extend into the inner, and not into the outer circumferential face and thus the packaged rings can be checked only with difficulty concerning their correct positioning. If such a notch extended from one of the annular faces to the outer circumferential face (that is, the running face of the piston ring), the latter would no longer have the required sealing properties.
It is further generally known to identify piston rings by stamping the annular faces. Such a method, however, is generally not acceptable because of the resulting protrusions of material and the damaging of the wear-resistant layers which are at least partially applied to the running faces.
SUMMARY OF THE INVENTION
It is an object of the invention to so improve the above-outlined method of identifying piston rings of asymmetrical cross section that an inverted position of any individual piston ring in a package can be readily detected and further, the marking does not adversely affect the properties of the piston ring.
This object and others to become apparent as the specification progresses, are accomplished by the invention, according to which, briefly stated, the marking is applied in one operational step exclusively on the upper surface of one of the annular faces and one part of the running face (outer circumferential face) of the piston ring.
It is an advantage of the above-outlined method according to the invention that the installing personnel can determine immediately upon visual inspection of the outer face of the packed piston rings whether all rings are positioned in their proper orientation.
BRIEF DESCRIPTION OF THE FIGURE
The sole FIGURE is a perspective view of a piston ring having a marking thereon applied with a method according to the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Dependent upon the particular type of piston ring, the marking may be applied either over one part or over the entire axial height of the running face of the ring. Preferably, the marking extends from that annular face of the piston ring which is to be oriented towards the combustion chamber in the internal combustion engine.
According to a preferred embodiment of the invention, the identification of the piston ring comprises the application of a relatively thin foil which is made of a synthetic material (for example PVC) and which, because of the earlier-described reasons regarding the stringent requirements concerning the running face of the piston ring, is less than 2μ thick. It is a significant advantage of this embodiment that such a marking which extends from one of the annular faces onto the running face, does not adversely affect the sealing properties of the ring during its service since the marking is worn off immediately as the piston starts its operation. Further, the piston rings may be marked at the annular face and the running face by means of a colored layer which may be stamped or sprayed onto the piston ring.
Turning now to the FIGURE, there is shown a cast iron piston ring 1 which has a slightly conical running face 2. When installed, the circular edge 3 of greater diameter is oriented towards the oil sump of the internal combustion engine. In the vicinity of the piston ring gap 4, there is provided a marking 5 which, in the illustrated embodiment, is formed of a foil having a thickness of 1μ and which has a color that differs from that of the piston ring. The marking extends from an annular surface 6 over only one portion of the conical running face 2.
In accordance with another preferred embodiment of the invention, the marking is provided by etching. In such a case the metal is treated with an etching agent only on the locations to be marked, that is, in the vicinity of the piston ring gap. The etching agent dissolves the metal at these locations up to an adjustable depth of less than 2μ and thus the marking does not adversely affect the sealing function of the piston ring. A similarly small-quantity material removal from an annular ring face and the running face may be effected by an electrolytic or a thermal treatment.
According to another preferred embodiment of the invention, the marking is applied galvanically, that is, in appropriate baths a metallic deposit is provided by electrolysis at the locations to be marked. The thickness of the deposited layer depends from the intensity and duration of the current. Similarly, the marking may be applied by plating, that is, by the application of a thin metal layer which in color differs from the ring body; such a metal layer is rolled under pressure onto the ring body in a hot condition. During such an operation, the metal layer becomes welded to the base body. Copper, nickel and aluminum may be used as the metal layer. It is to be understood, however, that this particular method is not limited to these three metals.
In accordance with still another embodiment of the invention, the marking may be applied by sandblasting.
It will be understood that the above description of the present invention is susceptible to various modifications, changes and adaptations, and the same are intended to be comprehended within the meaning and range of equivalents of the appended claims. | Piston rings of asymmetrical cross section are identified by providing a surface marking which extends from one flank face of the piston ring to the outer circumferential face (running face) thereof. | 8 |
FIELD OF THE INVENTION
The field of the invention is subterranean safety valves of the flapper type and more particularly vortex control features that allow the flapper to close in high velocity fluid flow applications.
BACKGROUND OF THE INVENTION
Subsurface safety valves generally have a flapper that is closed by a torsion spring that is mounted on a pivot pin for the flapper. A hydraulic control system actuates a piston to move a flow tube in the valve passage against the flapper to hold it open. If pressure in the hydraulic system is removed or lost, the closure spring acts on the flow tube to lift it away from the flapper that until that time had been behind the flow tube in a recess in the housing. Once the flow tube moves up the torsion spring in the flapper pivot shaft would do the work of starting rotational movement of the flapper toward its conforming seat. When the flapper contacted the seat the pressure of the fluid below kept the flapper in that closed position sealed against the flapper seat. Pressurizing the control system again brought the flow tube against the closed flapper and made it pivot off the seat back to the open position.
As safety valves were made with larger flow bores and dealt with higher velocities particularly in gas service transient vortexes were formed of high pressure zones that changed location depending on the velocity. At certain flow passage dimensions and flow velocities these high pressure zones occurred in front of an open flapper to create a sufficient hold open force that the torsion spring was unable to move the flapper to the closed position even after the flow tube was raised to allow such flapper movement.
In the past, in addressing the larger sized flapper safety valves and the limitations of the torsion spring to move an ever heavier flapper, designs were developed along the lines of providing an assist to the torsion spring to start the flapper moving toward the closed position when the flow tube was raised up. U.S. Pat. No. 6,227,299 used a leaf spring 122 located behind the flapper 86 to add a closing force. US Publication 2009/0151924 uses a shape memory alloy closure spring to get a boost in the flapper closing force. Going in the opposite direction, U.S. Pat. No. 7,703,532 holds the flapper open with movably mounted magnets and U.S. Pat. No. 7,270,191 provides a mechanism to open the flapper when it will not go from the closed to the open position with the hydraulic system. US Publication 2009/0032238 uses repelling magnets in the housing and the flapper to give an assist to a torsion spring on the flapper pivot pin. U.S. Pat. No. 7,448,219 is a hingeless flapper design that shapes the flapper to be aerodynamic so that it can operate responsive to the flow passing by in an automotive application. U.S. Pat. No. 7,644,732 uses a bypass technique for dealing with pressure surges in a lubrication system when the circulating oil is still cold.
The various solutions discussed above have in common a focus on adding a closing force when it is time for the flapper to go to the closed position. The present invention addresses the configuration of the flow passage to reduce or eliminate the effect of flow induced pressure transients that can overcome the ability of the flapper torsion spring to close it in high velocity fluid flow situations in the order of 300 feet per second or higher. Rather than adding to the mechanical closing force applied to the flapper, the present invention focuses on dissipation of flow induced moving pressure gradients that can act on the flapper at the time it needs to close and reducing their affects by shaping the profile of the flow passage in the vicinity of the flapper or the flapper itself so that the localized pressure differentials are not large enough to overcome the torsion spring trying to close the flapper. Those and other aspects of the present invention will become more apparent to those skilled in the art from a review of the description of the preferred embodiment and the associated drawings while recognizing that the full scope of the invention is provided by the appended claims.
SUMMARY OF THE INVENTION
The problem of flappers that will not close due to high velocity gas rushing past and creating a vortex that has zones of high pressure pressing the flapper against the force of the torsion spring is reduced or overcome with modifications in the passage through a subsurface safety valve so as to reduce the intensity of the vortex to allow the torsion spring to pivot the flapper to closed position. Various shapes are inserted adjacent the flapper base to create turbulence to minimize or prevent the vortex and the associated pressure increases that would otherwise prevent flapper closure with the flow tube retracted. Inserts that create turbulence are placed in a recess that in part holds the flapper when it is rotated to the open position. Additionally and alternatively the flapper itself can be machined so as to create a larger annular space behind the flapper when it is open so that some part of the generated vortex can be used to push the flapper to the closed position and to offset the high pressure zones created on the other side of the open flapper.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a prior art view of a flapper in the open position even after the flow tube moves uphole and flow passing through the passage that holds the flapper open due to a vortex causing high pressure;
FIG. 2A schematically shows the vortex against the flapper to hold it open in the prior art;
FIG. 2B illustrates the vortex shown in FIG. 2A and the high velocity flow passing straight through as the flapper is held open in the prior art;
FIG. 3 shows one form of a device to reduce the pressure in the vortex using a partial sleeve that comes to a point directed at the incoming flow and has opposed sides sloping away from the leading point;
FIG. 4 puts an insert in the groove where the flapper is located when it is open showing a series of transverse ridges; and
FIG. 5 shows an insert member in the groove where the flapper is located in the open position where the insert has an internal open space.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
As an introduction to the issue addressed by the invention FIG. 1 illustrates a tubular string 10 that has a safety valve housing 12 secured to the string 10 at opposite ends 14 and 16 . In the position of FIG. 1 the flow tube (not shown) has already been raised by a control system (not shown). Normally, the raising of the flow tube allows a torsion spring 20 about a pivot shaft 18 to apply its stored potential energy force and rotate the flapper 22 toward a schematically illustrated seat 24 . All the components of the housing 12 are not shown to add clarity to the identification of the issue using FIG. 1 . Arrow 26 represents the incoming high velocity stream that is most likely to be gaseous and in the order of about 300 feet per second or higher to cause the problem. Flow lines 28 graphically illustrate how most of the flow goes straight through the housing 12 in a direction toward the surface. However, depending on the velocity and the composition of the passing fluid some of the flow begins to ebb into the recess 30 and create a vortex 32 generally that begins away from the location of the flapper 22 and works its way around the housing 12 in the recess 30 . The vortex creates a high pressure concentration that is shiftable with the velocity that passes through the housing 12 . In the beginning as the velocity picks up the vortex 32 is located near the lower end 34 of the flapper 22 . At that location, the vortex 32 can actually be an aid to closure of the flapper 22 as it can pass through the gap 36 between the inside of the recess 30 and the housing 12 . Once reaching the small annular space 38 defined by the tapered surface 40 on flapper 22 and the housing 12 , the presence of the higher pressure at location 38 helps push the flapper away from wall 42 . However as the velocity increases and the center of the higher pressure vortex 32 moves closer to the surface and toward the pivot shaft 18 the moment balance shifts and there is an ever greater moment acting on the top side 44 of the flapper that can be easily in excess of the closing moment applied by the torsion spring 20 as aided by what remaining portions of the vortex 32 still in the vicinity of the gap 36 .
FIG. 2A adds to the schematic representation of how the vortex 32 works its way circumferentially to the top surface 44 of the flapper 22 . FIG. 2B is the same illustration as FIG. 2A but showing a different viewing angle for more of a perspective view. Should the velocity at the time the flow tube is raised in an effort to have the torsion spring 20 rotate the flapper 22 to a closed position against its seat 24 , the result can be that there is no flapper 22 movement at all. This can defeat the operation of the safety valve and can cause a blowout that would otherwise be prevented by the proper operation of the safety valve.
There are several ways that this situation can be addressed and three variations are illustrated in FIGS. 3-5 as preferred without any intent on limiting the variety of the approaches that look to reconfigure the internal passage in the housing 12 or the relation of the passage 44 to the flapper 22 or/and shaping of the flapper so that the vortex 32 is minimized in its intensity to the point where the torsion spring 20 can close the flapper 22 ′ as needed or in the ideal case prevent the vortex 32 from forming at all. In FIG. 3 the shoulder 46 and the flapper base 48 define the recess 30 ′ between them. Since the view in FIG. 3 is in section, only one half of the insert 50 is illustrated. The balance of the insert 50 that is not shown is preferably the mirror image of what is depicted. As a result the shape forms a downhole oriented point that can be sharp or blunt 52 from which opposed sides 54 extend and diverge in a direction toward the surface. The flow direction is given by arrow 56 . The thickness of the insert 50 as well as its shape can be optimized using Computational Flow Dynamics software that can create a three dimensional model of the flow regime through the passage 44 . Thus the height of the insert 50 can be varied to be taller, shorter or about the same height as the shoulder 46 that defines the recess 30 ′.
In a variation of the FIG. 3 design the insert 50 can be shaped to be a cylindrical member that fills partially to totally that portion of the recess 30 ′ that continues beyond the sides of the flapper 22 ′ so that in essence the circumferential extent of the recess 30 ′ is somewhat wider that the width of the flapper 22 ′ and that is it. Alternatively the flapper base 48 can be extended to accomplish the same result in a one piece rather than a two piece construction.
Another option is shown in FIG. 4 where the insert 58 is similarly positioned as in FIG. 3 and this time has a series of ridges such as 60 and 62 that are transverse to the direction of flow 64 that would otherwise cause the vortex 32 to form. The number and height and orientation of the ridges can also be optimized for the expected flow velocities. There can be ridge combinations that are transverse as shown in FIG. 4 combined with some ridges that are closer to parallel to the flow direction. A surface roughening on the face of the insert that faces the passage 44 is another alternative to control the vortex 32 ′.
Another approach is seen in FIG. 5 where the insert 65 has a void 66 that in the FIG. 5 is illustrated as square. Here again as in FIGS. 3 and 4 what is shown is a part of the insert 64 without the mirror image of it that is not in the illustration. Here again the void shape can be varied and optimized by mathematical modeling. There are other options for vortex control that can be implemented. For one the width of the gap 36 can be varied. Another approach is to increase the volume of the space behind the flapper and the surrounding housing. One example is to machine grooves on the back side of the flapper that faces the wall 42 ′ such as schematically illustrated by the dashed line 68 . There is a limit to the extent that the grooves on the back of the flapper can be used especially in the larger sizes as the flapper has to take large pressure differentials when closed and adding grooves can promote flapper distortion under maximum working pressure differentials to the point where leakage can occur. The idea on the back of the flapper is to create empty space behind the flapper to enable the vortex 32 to get into that space and add a closing moment that can help the torsion spring close the flapper.
It should also be noted that as the velocity increases the vortex 32 moves closer to the pivot shaft 18 and has a much smaller moment arm in the high pressure zone that it creates. That is one reason that the various inserts of FIGS. 3-5 end at the flapper base 48 . Optionally there can be a gap between the insert of any of the illustrated configurations or others that can be developed with mathematical modeling and the flapper base.
Another option to get an assist to the flapper 22 ′ is illustrated in FIG. 3 . A passage or passages 70 can start at passage 44 at a location 72 that is above the shoulder 76 where the flow tube 77 lands when the valve is in the open position. When the vortex 32 is centered on the flapper 22 ′, the tubing pressure in the passage 44 can be communicated to the zone behind the flapper 22 ′ at 74 . The passage 70 can be run as shown in FIG. 3 or it can use an external jumper if the passage from location 72 is run to the exterior face 79 and then jumpered to the outer face and into a lateral bore of the housing 81 in behind the flapper 22 ′.
While the illustrated valve is shown as operated with a flow tube 77 other designs using flappers that operate without a flow tube are also contemplated. Such devices can be powered by magnetic or other force fields to move the flapper between the open and closed positions.
The above description is illustrative of the preferred embodiment and various alternatives and is not intended to embody the broadest scope of the invention, which is determined from the claims appended below, and properly given their full scope literally and equivalently. | The problem of flappers that will not close due to high velocity gas rushing past and creating a vortex that has zones of high pressure pressing the flapper against the force of the torsion spring is reduced or overcome with modifications in the passage through a subsurface safety valve so as to reduce the intensity of the vortex to allow the torsion spring to pivot the flapper to closed position. Various shapes are inserted adjacent the flapper base to create turbulence to minimize or prevent the vortex and the associated pressure increases that would otherwise prevent flapper closure with the flow tube retracted. Inserts that create turbulence are placed in a recess that in part holds the flapper when it is rotated to the open position. | 4 |
BACKGROUND OF THE INVENTION
The present invention relates to a masking member which protects a part of an article from a surface treatment such as coating, plating, vacuum evaporation, phosphatizing, and the like. More particularly, the present invention relates to a masking member consisting of an elastic sheet having a groove(s) for bending in a selected position(s) on one or both sides of said sheet. When a surface treatment is effected on the surface of an article, and if said surface of said article has a part(s) on which said surface treatment should not be effected for the reason that another surface treatment is effected on said part(s) after said surface treatment or said surface treatment spoils the appearance of said article and so on, said part(s) of said surface of said article may be covered and protected with said masking member.
DESCRIPTION OF THE PRIOR ART
Hitherto, adhesive tape has been used as a masking member to protect a pillar, frame, and the like. Namely, the adhesive tape is wound round said pillar, frame, and the like to protect them from said surface treatment and after said surface treatment, said adhesive tape is removed from said pillar, frame, and the like. Said pillar, frame, and the like may be not effected by said surface treatment since said pillar, frame, and the like was covered with said adhesive tape during said surface treatment.
Nevertheless, adhesive tape as a masking member has faults in that attaching and removing of the adhesive tape to/from a pillar, frame, and the like take time and have a high labor cost, and further, the adhesive tape wound round a pillar, frame, and the like is buried in the layer of said surface treatment and it is very difficult to find the outer end of said buried adhesive tape to remove said adhesive tape. Said faults of adhesive tape may seriously obstruct a mass-production line such as a coating line for automobiles.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to save trouble when the masking member is attached/removed to/from a part to be protected such as a pillar, frame, and the like. According to the present invention, there is provided a masking member consisting of an elastic sheet having groove(s) for bending in selected position(s) on one or both sides of said sheet. Said masking member may be attached on a pillar, frame, and the like by bending said masking member along said groove(s) to surround said pillar, frame, and the like.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 to FIG. 4 relate to a first embodiment of the present invention.
FIG. 1 is a cross sectional view of the masking member.
FIG. 2 is a partial perspective view of both ends of the masking member.
FIG. 3 is a cross sectional view showing that the masking member is attached on a pillar.
FIG. 4A is a partial front view of the said pillar after coating.
FIG. 4B is a partial front view of the said pillar after the masking member has been removed.
FIG. 5 is a cross sectional view of the masking member of a second embodiment of the present invention.
FIG. 6 to FIG. 8 relate to a third embodiment of the present invention.
FIG. 6 is a cross sectional view of the masking member.
FIG. 7 is a plane view of the masking member.
FIG. 8 is a cross sectional view showing that the masking member is attached on a pillar.
DETAILED DESCRIPTION
FIG. 1 to FIG. 4 relate to a first embodiment of the present invention. Referring now to FIG. 1 to FIG. 6, a masking member (101) consists of an elastic sheet (111) made of polystyrene foam and having four parallel grooves (112) which are formed on a side of said sheet (111) at regular intervals. A flange part (113) is extended from one end of one side of said sheet (111) and further, a flange part (115) is extended from the other end of the other side of said sheet (111). Two holes (114) are formed in said flange part (113) while two projections (116) are formed on said flange part (115).
Said masking member (101) is attached on a part (110A) of a pillar (110) of a door of an automobile by bending said masking member (101) along said groove (112) to surround said part (110A) of said pillar (110) and said two projections (116) of said flange part (115) are respectively engaged in said holes (114) of said flange part (113) to secure said masking member (101) on the circumference of said part (110A) of said pillar (110) as shown in FIG. 3.
After said masking member (101) has been attached on said part (110A) of said pillar (110) as above described, said pillar (110) is coated by spraying a paint (110B) as shown in FIG. 4A and said part (110A) of said pillar (110) which is covered with said masking member (101) is not coated with said paint (110B). After coating, said masking member (101) is removed from said part (110A) of said pillar (110) by hand, hook, and the like and said pillar (110) has said part (110A) which is not coated with said paint (110B) as shown in FIG. 4B.
FIG. 5 relates to a second embodiment of the present invention. Referring now to FIG. 5, a masking member (102) consists of an elastic sheet (121) made of a laminated sheet (121) of a polystyrene foam sheet (121A) and a polypropylene film (121B) and having four parallel grooves (112) which are formed on said polystyrene sheet (121A) side of said laminated sheet (121) at regular intervals. A flange part (123) is extended from one end of one side of said sheet (121) and further, a flange part (125) is extended from the other end of the other side of said sheet (121). Two holes (124) are formed in said flange part (123) while two projections (126) are formed on said flange part (125).
Said masking member (102) is attached on a pillar, frame, and the like the same as in the first embodiment. In this next embodiment, said masking member (102) may have a higher solvent resistance and a higher heat resistance than the masking member (101) of the first embodiment since said polypropylene film (121B) protects and reinforces said polystyrene foam sheet (121A) so that said masking member (102) can be reused.
FIG. 6 to FIG. 8 relate to a third embodiment of the present invention. Referring now to FIG. 6 to FIG. 8, a masking member (103) consists of a molded elastic sheet (131) made of polypropylene in which 30% by weight of calcium carbonate is mixed. Said masking member (103) comprises a pair of hill parts (131A) and (131B), a connecting part (131C) between said hill parts (131A) and (131B), and a pair of flange parts extending respectively from the outer ends of said hill parts (131A) and (131B), and two insert parts (133) are extended from the outer end of said flange part (131D) while two holes (134) are formed in said flange part (131E). Two grooves (132A) are formed between said hill parts (131A), (131B) and said connecting part (131C) and further a groove (132B) is formed between said hill part (131A) and said flange (131D). Said masking member (103) may be produced by vacuum forming, press, extrusion, injection molding, and the like. Said masking member (103) is attached on a part (120A) of a pillar (120) to be protected from a coating by bending said masking member (103) along said grooves (132A), and (132B), to surround said part (120A) of said pillar (120) and said two insert parts (133) of said flange (131D) are respectively inserted into said holes (134) of said flange (131E) to secure said masking member (103) on said part (120A) of said pillar (120) as shown in FIG. 8. Said masking member (103) has an excellent solvent resistance and an excellent heat resistance since said masking member (103) is made of polypropylene in which calcium carbonate is mixed so that said masking member (103) can be reused.
The masking member of the present invention is made of an elastic sheet such as from plastics such as polystyrene, polyethylene, polypropylene, polyvinylchloride, polyurethane, melamine resin, urea resin and the like; plastic foams of said plastics; laminated sheet of said plastic foams and said plastics; fiber sheet such as fabric, knitting, non-woven fabric, paper, corrugated card board and the like; thermoplastic resin--impregnated fiber sheet; thermo-setting resin--impregnated fiber sheet; wooden sheet such as wood board, hardboard, plywood and the like; metal sheet and the like.
In cases where said masking member is made of plastics, it is desirable to mix inorganic filler such as calcium carbonate, talc, bentonite, stone powder, blast furnace slag, flyash, and the like into said plastics since heat resistance, mechanical properties and the like of said masking member are improved by said inorganic filler and further, when used masking member is burnt in a combustion furnace, a smaller combustion energy is produced so that said combustion furnace will stand long use. Usually, 10 to 500 weight parts, desirably 20 to 400 weight part of said inorganic filler are mixed into said plastics. Polyolefin such as polyethylene, polypropylene and the like is desirable plastics for the material of the masking member of the present invention since said polyolefin has high solvent resistance and is inexpensive, and of course, polyolefin in which said inorganic filler is mixed is a desirable material for said masking member. Polystyrene foam is also a desirable material for said masking member since said polystyrene foam is light and inexpensive, nevertheless, since said polystyrene foam has a low solvent resistance and a low heat resistance, it is desirable to laminate a suitable plastic onto said polystyrene foam. | A masking member consisting of an elastic sheet having a groove(s) for bending in a selected position(s) on one or both sides of said sheet is provided in the present invention. Said masking member is used to protect a pillar, frame, and the like from a surface treatment such as coating. | 1 |
The present invention relates to a process for the production of polylactide (PLA). Particularly, the present invention relates to an improved process where the goal is to recover a maximum of useful matters in order to recycle without loss and so significantly improving the global yield of the production process of PLA when starting from lactic acid.
BACKGROUND
Mainly two types of process have been described for the production of PLA; the first one consists in a direct polycondensation of lactic acid, as described for instance in JP patent 733861; such type of process is limited by the use of a solvent and the difficulty of removing water out of the reaction medium.
It is well known that in a second type of usual process for producing PLA starting from lactic acid, a significant loss of products, including lactic acid, lactide, oligomers of lactic acid and similar, occurs at each step of the global polymerization process; such steps may be summarized as follows: (i) oligomerization of lactic acids into oligomers, (ii) cyclization of the oligomers into lactide species, (iii) purification of lactide to obtain a suitable grade to start the last step which is the polymerization by ring opening of the purified lactide. Of course after this last step a devolatilization shall take place to recover the non-converted lactide.
Depending of the various processes for the production of PLA, it may be said that a lot of matters are lost all along the achievement of the process, so decreasing considerably the overall yield of said process. Indeed, if we take as a reference, a theoretical process without any recycling, the overall yield is as low as about 50% (molar).
It was therefore envisioned in the past to control certain partial recycling of streams issued from the step of evaporation of water from the starting lactic acid aqueous solution, from the step of oligomerization and from the step of the cyclization reaction; with such recycling operations, the overall yield has reached values as high as 75% (molar); however, even with those efforts which have been made and described to recover and finally recycle such type of lost product, this is not yet satisfactory to conduct an industrial process.
Therefore, there is a need for a process which enables not only to drastically reduce such loss of products, but mainly to incorporate in a global process the implementation of the recovery of the lost products and a process to convert such products to the starting monomer or its derivatives.
Therefore, the object of the present invention is to provide a process for the production of PLA wherein the recovery of the oligomers of lactic acid, lactide, and catalytic residues as well are implemented in order to treat and convert them into the starting monomer or its derivatives.
Another object is to recover the residues at each step of the process.
A further object is to treat the residues of lactic acid oligomers.
Another object is to implement the recovery and the recycle of the streams of lactic acid and water.
Another object is to provide a trans-esterification process to convert the oligomers residues with an alcohol.
Finally the process of the invention should also provide for treating the formed lactate compounds by hydrolysis in order to recover the alcohol and the lactic acid or its derivatives.
At least one of these objectives is met by the process of the invention.
DETAILED DESCRIPTION
The process of the present invention is also described in view of the accompanying drawings where FIG. 1 is representing the global flow sheet of a process for the production of PLA with the recovery steps and conversion steps to the starting monomer.
DESCRIPTION OF THE GLOBAL PROCESS
The present invention provides an integrated process for the production of polylactide (PLA) comprising the steps of:
(1) Water evaporation from the lactic acid aqueous solution starting stream; (2) Oligomerization of lactic acid and recycle of reaction water and unconverted lactic acid; (3) Cyclization of the lactic acid oligomers and production of crude lactide and recycle of unreacted monomers, catalytic residues and heavy products; (4) Purification of the crude lactide and recycle of lactic acid, water, heavy components, catalytic residues and impurities; (5) Ring opening polymerization of the purified lactide and production of PLA; (6) Purification of the PLA by devolatilization and recycle of non-reacted lactide;
wherein
recycle of step (2) comprises water, which is purged, and lactic acid which is recycled to reactor ( 20 ); recycle of step (3) is sent to trans-esterification reactor ( 80 ); recycle of step (4) comprising (i) the light components, is sent to reactor ( 20 ) the other part to the hydrolysis reactor ( 90 ), and (ii) the heavy components stream is sent to trans-esterification reactor ( 80 ); recycle of step (6) is sent partially to step (4) and the rest is sent to trans-esterification reactor ( 80 ).
The first step of the process to produce PLA consists in the removal of water from the starting aqueous solution of lactic acid (from 50 to 100% concentration) and the second step consists in the oligomerization of the lactic acid monomers into oligomers of low viscosity and molecular weight, generally comprised between 400 and 5,000 Dalton, in presence or not of a catalyst like for example a tin based catalyst. Typical temperature and pressure range for these two steps are respectively 100° C. to 200° C. and 5 mbara to 500 mbara. The molecular weight was measured by chromatography by gel permeation compared to standard polystyrene in chloroform at 30° C.
From these first and second steps, the process of the invention provides for the recovery of water, non-reacted lactic acid, oligomers of lactic acid.
The Applicant has noted that the residues of water and lactic acid are relatively pure, and therefore may be directly recycled to the evaporation step or the oligomerization step.
The Applicant has found that such a recycling of lactic acid could represent up to 5-15% by weight of the incoming lactic acid stream.
The oligomers coming from the step of oligomerization are then sent to the cyclization step which consists of treating the oligomers in a cyclization reactor, in the presence of a usual catalyst for such reaction like a tin based catalyst. From this third step, and besides the obtained crude lactide stream which will be sent to the purification, it is necessary to recover the unreacted oligomers, the non volatile impurities, the high boiling point lactic acid oligomers, the low molecular weight polylactic acid, having a molecular weight comprised between 2,000 and 8,000 Dalton, as well as the heavy residues and the catalytic residues which all form the cyclization residues. Typical temperature and pressure range for this step are respectively 200° C. to 320° C. and 5 mbara to 80 mbara.
These cyclization residues are sent back to the oligomerization step. However it is important to note that in order to avoid dramatic accumulation of catalytic residues in the system as well as degradation by-products, a purge is absolutely needed, which also contribute to the elimination of impurities giving rise to unwanted color. The products of the purge are then sent to the trans-esterification reactor ( 80 ).
During the fourth step, which is the purification of the crude lactide stream which may comprise different types of purification units like distillation means, crystallization means and analogs, it is recovered a light components stream containing lactic acid and water which is divided into two sub-streams, the first, representing from 10 to 100% by weight of the light components stream, is sent to the hydrolysis reactor ( 90 ) while the second, representing from 0 to 90% by weight of the light components stream, is recycled to reactor ( 20 ), while a bottom stream, containing heavy oligomers, lactide and impurities constituting stream will be recycled to the trans-esterification reactor ( 80 ).
The purified lactide is finally sent to the step of polymerization by ring opening to form PLA, having a molecular weight comprised between 10,000 and 200,000 Dalton.
This polymerization step is followed by a devolatilization step to purify the obtained PLA and to recover unreacted monomers and diluents as well as impurities.
The Applicants have now found that by operating the improved process of the invention, which comprises the steps of the water evaporation, oligomerization, crude lactide production, purification of the crude lactide, polymerization of the purified lactide by ring opening (ROP), devolatilization and the recovery of PLA, the improvement consists in:
(i) recovery water and lactic acid in steps evaporation, oligomerization, cyclization and purification, and sent them back to step of evaporation and/or oligomerization, (ii) recovery of oligomers of lactic acid, lactide, catalytic residues of steps cyclization, purification, and devolatilization and sent them back to a trans-esterification reactor, where a trans-esterification reaction shall take place, and finally (iii) send the so formed alkyl lactate to a hydrolysis step to recover the starting monomer.
According to the process of the present invention, the trans-esterification reaction may be operated in accordance with known processes and under usual conditions; such a reaction may be achieved in one or more than one reactors at a temperature comprised between 80 and 200° C. and at a pressure comprised between the atmospheric pressure and 10-50 bara and in the presence of a catalyst.
According to one embodiment of the process of the present invention, the recycle stream from cyclization (noted step (3)) and the heavy components recycled from lactide purification (noted step (4)) and the part of stream coming from devolatilization (noted step (6)) are collected and sent to the trans-esterification reactor ( 80 ) where the trans-esterification reaction is conducted in one or more than one continuous stirred reactors working at a temperature ranging between 80 and 200° C., preferably between 100 and 180° C. and at pressure ranging between 1 and 20 bara, preferably between 2 and 15 bara, and finally the recovery of a stream comprising alkyl lactate which is sent to the hydrolysis reactor ( 90 ).
Generally the catalyst is at least partially supplied with the flow recovered from the cyclization step coming from the production of crude lactide stream.
With the trans-esterification reaction an alkyl lactate is formed and recovered which is further sent to a hydrolysis step to finally recover the starting monomer.
Before being sent to the hydrolysis reaction, the crude alkyl lactate exiting the reactor ( 80 ) is first purified in order to separate the lactate molecules from the heavier molecules. With this purification step, it is generally expected to recover substantially 80 to 100% of the lactate molecules, based on the fed lactate molecules. Usually, to achieve such a separation, the mixture coming out of the trans-esterification reactor ( 80 ) is first sent to a distillation step operated under pressure of 0.01 to 4 bara preferably between 0.1 to 1 bara and at a temperature comprised between 40 to 180° C., preferably between 60 to 150° C., said distillation step comprising one or more than one distillation columns or equivalent apparatus, where it is recovered at one side, the light components like lactate molecules which are then sent to the hydrolysis and on the other side the heavy components such as the catalytic residues, oligomers and the unreacted products, which are partially recycled to reactor ( 80 ) for trans-esterification and the rest is purged and optionally treated for example by filtration or decantation to separate the catalytic residues from the oligomers. These catalytic residues can be sent back to trans-esterification and/or oligomerization and/or cyclization reactors as such or with an additional treatment (e.g. drying).
The hydrolysis reactor (noted 90 ) is receiving, after distillation, the stream from the trans-esterification reactor as well as the part of light components coming from the purification of lactide and which is directly sent to the hydrolysis reactor. The hydrolysis reactor is then operated in accordance with the usual process to achieve such reaction and in accordance with usual conditions.
The hydrolysis reaction may be summerized as follows:
Alkyle lactate+water→lactic acid+alcohol.
According to one embodiment of the present invention, this type of reaction is achieved either in batch or continuously, and the reactor for such reaction may be realized generally in a reactive distillation column, a plug flow reactor or a continuous stirred reactor system operated at a temperature comprised between 70 and 180° C., preferably 90 to 150° C. and at a pressure comprised from 0.01 and 10 bara, preferably between atmospheric pressure and 3 bara.
The alcohol, which is most often an aliphatic alcohol having from 1 to 12 carbon atoms might be withdrawn from the reaction medium in order to increase reaction efficiency. The hydrolysis reaction may be conducted in the presence of a catalyst, which may be lactic acid itself.
The finally recovered lactic acid may be further concentrated and then recycled to the oligomerization reaction, or to the upstage lactic acid production step.
The process of the invention has the unexpected advantage that it can recover all the residues which are mentioned like water, lactic acid oligomers and lactide, that cannot be done in the previous processes, and therefore, the process of the invention enables to reach very weak amount of lost products.
The overall process for producing PLA and taking into account the steps of the present invention to drastically reduce the loss of products while recovering a maximum and recycling the products like water, lactic acid, oligomers, catalytic residues at the different steps may be described in view of FIG. 1 which represent a flow sheet of the process.
An aqueous solution of lactic acid is subjected to water elimination through evaporation. The eliminated water recovered from reactor ( 20 ) which contains some lactic acid is then recycled to reactor ( 20 ), while the main flow coming out from reactor ( 20 ) is sent to the oligomerization reaction in reactor ( 30 ). During said oligomerization reaction, some water, lactic acid, which has not oligomerized are withdrawn from reactor ( 30 ) and after separation of the water, which is simply purged, the remaining lactic acid is recycled to reactor ( 20 ).
The main flow coming out from reactor ( 30 ) is sent to the cyclization reactor ( 40 ) for the production of a crude lactide stream. From reactor ( 40 ), a flow is withdrawn containing the unreacted oligomers, catalytic residues and heavier products, said flow being sent to the trans-esterification reactor ( 80 ).
The crude lactide stream resulting from cyclization is then sent to purification of lactide and which is represented by reactors ( 50 ), comprising any well known apparatus used for such purification and comprising at least distillation and/or melt crystallization means.
From purification step, represented by reactor ( 50 ), the light components lactic acid and water are recovered and recycled to reactor ( 20 ), while part of it, which may be up to 100%, is sent to the hydrolysis reactor ( 90 ) where lactic acid can act as catalyst of the hydrolysis reaction. Depending on lactic acid concentration in this stream and hydrolysis process efficiency, the minimum content of the light components stream to be sent to the hydrolysis reactor evolves between a few to several tens of percents. On the other hand the heavier components, the impurities and catalytic residues withdrawn from purification step, represented by ( 50 ), are recovered and recycled to the trans-esterification reactor ( 80 ).
The purified lactide is then sent to ring opening polymerization in reactor ( 60 ) and the obtained PLA is purified in a devolatilization reactor ( 70 ).
From the devolatilization reactor ( 70 ) it is recovered and recycled the non reacted lactide which is withdrawn and recycled partially to lactide purification or directly to the trans-esterification unit ( 80 ).
The process of the invention is further described by the following examples which are in no way limitative of the scope of the invention.
EXAMPLES
Example 1
We started with 6,000 Kg of an 88% aqueous solution of lactic acid.
This solution was subjected to water elimination by heating at a temperature of 100° C. and under reduced pressure of 250 mbara.
Water recovered was purged and the lactic acid recovered was recycled to reactor ( 20 ).
The concentrated lactic acid (100%) is sent to reactor ( 30 ) for oligomerization, which is operated at temperature of 160° C. and at a reduced pressure of 250 and down to 80 mbara, to produce oligomers of lactic acid having a molecular weight of about 950 Dalton (comprised between 900 and 1,000 Dalton.).
From reactor ( 30 ) water is withdrawn and purged, while unreacted lactic acid is recovered and recycled to reactor ( 20 ).
The oligomers formed in reactor ( 30 ) were then sent to the cyclization step in reactor ( 40 ).
The cyclization of the oligomers of lactic acid was achieved in the presence of Sn octanoate as catalyst, at a temperature of 250° C. and pressure of 10 mbara and enabled to produce a crude lactide stream.
From reactor ( 40 ), the unreacted oligomers, the catalytic residues as well as the heavier components were withdrawn and the withdrawn flow was sent to the trans-esterification reactor ( 80 ).
The crude lactide stream coming out from reactor ( 40 ) was sent to the purification step of the crude lactide. Said purification comprises, in the present example, melt crystallization means ( 50 ), from which the heavy components withdrawn from melt-crystallization means ( 50 ) were recovered and sent to the trans-esterification reactor ( 80 ).
The obtained lactide was then subjected to ring opening polymerization in reactor ( 60 ) at a temperature of 185° C. during 30 minutes in the presence of Sn octanoate and the obtained PLA is purified in a devolatilization reactor ( 70 ) from which the non-reacted lactide was removed and recycled to lactide purification. In case of presence of catalytic or other impurities, devolatilization stream can be sent to trans-esterification reactor ( 80 ).
We finally recovered PLA with an overall molar yield of 96%.
Example 2
By way of comparison a process has been conducted with the recycling as described in the prior art, meaning at the evaporation step, at the oligomerization and cyclization steps. The overall molar yield obtained in said comparative process was of 78%. | The present invention relates to an improved process for producing polylactide where the goal is to recover a maximum of useful matters in order to recycle without loss and so significantly improving the global yield of the production process of polylactide when starting from lactic acid. | 2 |
RELATED APPLICATIONS
This application claims benefit of and priority to U.S. Provisional Application Ser. No. 61/800,153 filed Mar. 15, 2013 entitled Low-Profile Prosthetic Valve Structure, which is hereby incorporated herein by reference in its entirety.
BACKGROUND OF THE INVENTION
Replacing heart valves with prosthetic valves was, until recently, a complicated surgical procedure that involved cutting open the chest, establishing blood flow through a blood pump, stopping the heart, etc. This complicated procedure, even when performed perfectly, required extensive recovery time due to the invasiveness and damage done to access the implantation site. Additionally, the risk of infection or other complications is extremely high.
Numerous advancements have been made to develop prosthetic valves that can be implanted percutaneously, using a catheter to snake the prosthetic valve through the vasculature to the implantation site. If successful, the recovery time is greatly minimized relative to conventional open-heart surgery.
A designer of a percutaneously-delivered prosthetic valve is faced with numerous challenges, however. First and foremost is designing a prosthetic valve that can be compressed enough to be inserted into a catheter small enough to be navigated to the valve site through the vasculature. Other challenges include anchoring the valve at the valve site so the valve does not migrate after release; including a support structure for the valve that is robust enough to push the native, often calcified valve out of the way and prevent it from later interfering with the function of the new valve; ensuring that the new valve allows proper flow in a desired direction and effectively stops flow in the opposite direction; ensuring that no blood flows around the sides of the implanted device (this is known as perivalvular leakage); designing a prosthetic valve device that does not fail due to fatigue after hundreds of thousands of cycles of leaflet function; designing a valve that meets all of these criteria and can still be manufactured economically; and the list goes on.
These prosthetic valves, and their respective delivery catheters, are designed to replace a particular native valve, such as the aortic valve, for example. Percutaneous navigation to a valve is easiest, and least traumatic to the patient, when a smaller catheter is used. Smaller catheters, however, present challenges when designing effective prosthetic valves that can be compressed enough to fit, and slide, within the lumen of a small catheter, such as a 16 Fr or even a 14 Fr catheter. Significant strides have been made in recent years in designing prosthetic valves that have reduced profiles when in a catheter-loaded configuration. For example, the devices described in U.S. Patent Publication Number 2006/0271166 to Thill et al., the contents of which are incorporated by reference herein, can assume an elongated, unfolded configuration when loaded into a catheter and, when released from the catheter at a target site, resume a folded configuration. The present invention is directed to taking this innovative concept and presenting additional ways that the loaded configuration could present an even lower profile.
OBJECTS AND SUMMARY OF THE INVENTION
One aspect of the invention is directed to a prosthetic valve device that presents a low profile in a catheter-loaded configuration.
Another aspect of the invention is directed to a prosthetic valve device that is sized to replace an aortic valve and capable of being delivered using a small, flexible catheter.
Another aspect of the invention is directed to a prosthetic valve device that comprises two components are connected but positioned in series (spaced apart axially) in a delivery catheter to reduce the size of the delivery catheter required.
One aspect of the invention provides a device for replacing a native valve comprising: a stent; a tissue sleeve; and, an anchoring mechanism usable to secure said tissue sleeve within said stent; wherein, in a configuration inside a delivery catheter, said anchoring mechanism is not located within said stent; and wherein, in a deployed configuration, said tissue sleeve is located within said stent.
Another aspect of the invention provides prosthetic valve device that comprises a braided anchoring mechanism connected at a proximal end to a wireform.
Another aspect of the invention provides an implantable device that includes a support structure having an extended configuration and a folded configuration, the support structure having a first end, a second end and a preformed fold between said first end and said second end, wherein said preformed fold at least assists in inverting said first portion into said second portion when said support structure is released from a delivery device, and a prosthetic valve structure including a hinged end hingedly attached to said support structure first end, thereby allowing said support structure first portion to invert into said support structure second portion without inverting said prosthetic valve structure.
Another aspect of the invention provides an implantable prosthetic valve structure with a support structure that has a folded configuration in which the prosthetic valve structure extends, at least partially, into said support structure.
Another aspect of the invention provide a prosthetic valve device that includes a support structure that has inwardly curved sidewalls when it is in a folded configuration.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other aspects, features and advantages of which embodiments of the invention are capable of will be apparent and elucidated from the following description of embodiments of the present invention, reference being made to the accompanying drawings, in which
FIG. 1 is an elevation of an embodiment of the invention;
FIG. 2 is an elevation of an embodiment of the invention in a folded configuration;
FIG. 3 is a partial view of an embodiment of the invention;
FIG. 4 is a partial view of an embodiment of the invention; and
FIG. 5 is a partial view of an embodiment of the invention.
DESCRIPTION OF EMBODIMENTS
Specific embodiments of the invention will now be described with reference to the accompanying drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. The terminology used in the detailed description of the embodiments illustrated in the accompanying drawings is not intended to be limiting of the invention. In the drawings, like numbers refer to like elements.
Referring first to FIG. 1 there is shown a device 10 of the invention. Device 10 generally includes a support structure 20 , a valve assembly 40 , and a connection 60 between the support structure 20 and the valve assembly 40 . FIG. 1 shows the device 10 in an elongate configuration prior to being compressed in order to fit within the lumen of a delivery catheter. It can be seen that the support structure 20 , the valve assembly 40 , and the connection mechanism 60 are all linearly arranged along a longitudinal axis in a series configuration, with no overlapping of components.
With regard to the support structure, a dotted line 22 represents a preformed fold created in the support structure 20 that at least partially causes the device 10 to fold inwardly on itself when released from a delivery catheter. The support structure 20 can be described as having a first end 24 , a first portion 26 between the first end 24 and the preformed fold 22 , a second end 30 , and second portion 32 between the second end 30 and the preformed fold 22 .
The valve assembly 40 includes tissue valve 42 attached to a wireform 44 . The wireform 44 gives structural integrity to the tissue valve 42 .
The connection 60 between the valve assembly 40 and the support structure 20 is described in more detail below.
FIG. 2 shows the device 10 of FIG. 1 in a fully expanded, delivered configuration. The device 10 has folded inwardly on itself such that the fold 22 is now defining the proximal end of the support structure 20 . As the device 10 folded, the wireform 40 , which contains a tissue valve 42 , is drawn into the support structure 20 . Because the first portion 26 is now inverted, in other words, it is inside-out in comparison to its prefolded configuration of FIG. 1 , the connection mechanism 60 must hinge or pivot in order to maintain the orientation of the valve assembly 40 . Because the connection mechanism 60 hinges, when the first portion 24 inverts into the second portion 32 , the valve assembly 40 moves only linearly (axially) into the support structure 20 , as shown by the arrow 100 in FIG. 2 . Thus, only one preformed fold 22 is needed in the support structure 20 to allow the valve assembly 40 to maintain its orientation while moving axially.
FIG. 3 shows an embodiment of a connection mechanism 60 . The connection mechanism 60 may be a link 62 having two ring connectors 64 separated by a spacer 66 . The spacer 66 is sized to ensure that, in the elongated configuration, the connection mechanism 60 adequately separates the support structure 20 from the valve assembly 40 . The connection mechanism 60 may be constructed of a variety of bio-compatible material such as an alloy, including but not limited to stainless steel and Nitinol, or may be a polymer or other suitable non-metallic material.
FIG. 4 shows another embodiment of a connection mechanism 60 . This connection mechanism 60 may be a tether 70 having ends 72 that are tied to the wireform 44 of the valve assembly 40 and to the support structure 20 . The tether may be constructed of any suture material or may be a wire having suitable flexibility to be tied in a knot. The length of the tether 70 between the tied ends 72 constitutes a spacer 74 that is sized to ensure adequate separation of the support structure 20 from the valve assembly 40 in the elongated configuration of FIG. 1 .
FIG. 5 shows an embodiment of a connection mechanism 60 that is a single loop 80 . The loop 80 extends around the wireform 44 and a strand of the support structure 20 . The loop 80 is sized to ensure adequate separation of the support structure 20 from the valve assembly 40 in the elongated configuration of FIG. 1 .
Although the invention has been described in terms of particular embodiments and applications, one of ordinary skill in the art, in light of this teaching, can generate additional embodiments and modifications without departing from the spirit of or exceeding the scope of the claimed invention. Accordingly, it is to be understood that the drawings and descriptions herein are proffered by way of example to facilitate comprehension of the invention and should not be construed to limit the scope thereof. | A prosthetic valve assembly that includes a stent, a tissue sleeve and an anchoring mechanism. By loading the three components of the valve assembly into a delivery catheter in a series formation, such that no two components are located within each other, the size of the delivery catheter can be reduced. | 0 |
This application is a Continuation-In-Part of co-pending U.S. patent application Ser. No. 162,088, filed June 23, 1980 and now abandoned.
BACKGROUND AND SUMMARY OF THE INVENTION
The invention relates to a door operator comprising an electric drive motor unit mechanically connected to pulling means for a single or multiple panel door by a belt drive or the like. The belt is guided positively by three pulleys. The middle pulley is a drive pulley mounted on or integral with the motor drive shaft, and the other two pulleys are guide pulleys mounted on portions of a plate located on both sides of the drive pulley and pivotable on a shaft parallel to the drive shaft. The plate, which is spring loaded toward the middle position of its pivoting range, is provided with an extension which engages switching means located in the path of plate motion.
The door operator structure is used to monitor the door panel motion in case an obstacle is present in the path of the door. The obstacle may be a vehicle, another object, or even a person. For this reason, means are provided (sometimes by law in many areas) to stop or reverse the door motion in the presence of such an obstacle.
In this case, the drive belt connected to the motor unit to transmit the drive motion to the door drive means has been guided by two pulleys around said drive pulley mounted on or integral with the motor unit output element in such a manner as to provide for a sufficiently wide loop angle for the transmission of the drive power from the drive pulley to the belt, see German Gebrauchsmuster No. 7,817,731.
Mounting of at least the guide pulleys on a plate which is pivotable about an axis located outside the output shaft axis makes it possible for the belt portion under greater load, depending on the direction of drive, to apply on its pulley a force stronger than that applied by the other belt portion on its own guide pulley. When, because of the presence of an obstacle in the path of door motion, a particularly heavy load is applied to one belt portion while the motor drive continues, the plate is deflected by the belt under heavier load and operates, by way of an extension thereof, on one of the two switches. One of these switches stops or reverses the motor, so that the door moves away from the obstacle. The other switch, arranged in the other direction of plate deflection, also provides for stopping or reversing the motor to the opposite direction of door motion or motor drive. The fact that the basic loads related to the door motion may differ in the open position and the closed position is taken into account by adjusting the switch actuator. With normal load, depending on the belt portion under load, the spring loaded plate is deflected in one or the other direction by a longer or shorter distance without actuating the switch concerned. It is only when a determined deflection value is exceeded that one of the two adjustable stops of the extension engages one or the other switch. Therefore, this accident-preventing switching arrangement is primarily responsive to the amount of deflection. This entails disadvantages because a determined amount of deflection is allowed for the normal load range, which may result in plate rocking even with weak motion resistance in the normal load range, which, at appropriate resonance, triggers the switching arrangement even in the absence of an obstacle. Consideration must be given in this connection to the load variations which are applied by variable wind pressures on the door.
For the above reasons, the threshold value for door motion inhibition should be adjustable on the basis of local conditions such as wind effects. Moreover, the door should be operable manually when the drive operation is faulty or has failed. Generally, satisfactory accessibility to the device is desirable for the easy adjustment of the above-cited safety threshold value and disconnection of the drive on failure.
Thus, an object of the invention is to provide a door drive of this type which operates exactly and separately in normal operation and accident-preventing operations, and also generally permits an improved adjustment of the actuation threshold values in response to belt tension.
The invention also relates to the adjustment of the stopping or reversing of the drive motor when an obstacle is present in the path of motion of the door with the highest possible sensitivity; and to the reduction of production costs.
Finally, another object of the invention is to provide a drive unit which requires low-maintenance, generally, and particularly relative to the adjustment of the safety threshold value.
According to the invention, the drive motor is stopped or reversed for accident prevention in the presence of an obstacle by a force-responsive value determination. The actuating elements for the switch, switch covers, or the like, which can be mounted in fixed position, are located more or less directly on either side of the extension of the pivotable plate. The springs act on both sides of the extension and their values in the inactive state are predetermined so as to be large enough that, in normal operation, a deflection of the plate will not occur that could actuate one of the switches. Only for accident prevention, i.e., when the resistance to movement is sufficiently strong and its value rises above the level indicative of an obstacle, will the drive motor be reversed or stopped. Since the adjustment can be made precise by varying the spring load, in normal operation, plate deflection practically does not occur and no rocking develops in normal operation in response to relatively small periodic disturbances in the door motion. Therefore, the drive of the invention operates faultlessly with sensitive adjustment of the threshold from which the resistance corresponding to accident prevention rises.
In another embodiment of the invention, no switch with springs is used, but a photoelectric cell is influenced by a shield when the plate is deflected in response to an obstacle, so that the beam path between the photoelectric cell transmitter and receiver is interrupted. To adjust the switching threshold value, the plate is in contact with adjustable springs whose characteristic is thus responsive exclusively to the force ratios for which the plate deflection determining the switch condition occurs. The photoelectric cell also offers the advantage that it can be operated as a normally closed contact switch, i.e., is always on, when the drive is operative. If the photoelectric cell fails or its operation is otherwise affected, the danger of the drive operating in the presence of an obstacle is avoided.
In a preferred form of this embodiment, the shield part comprises elements near the middle of the plate deflection range, on both sides of the beam path, so that always the same photoelectric cell is operated for both directions of deflection. Therefore, only one switch is needed. Basically, the beam path of the photoelectric cell can be directed perpendicularly to the plane of the plate. In another embodiment, the photoelectric cell beam path may be parallel to the plane of the plate, which, in some cases, provides for an advantage in respect to the space occupied by the structure. The structure of the shield part or shield elements is readily adaptable to this embodiment.
The springs which engage the plate on opposite sides are preferably in the form of two-armed springs pivotably mounted on a pin. The ends of the arms of said springs extending away from the plate are in contact with setscrews which are threaded into a fixed part. This fixed part is preferably the edge of the frame housing which holds the motor, the plate, and the motor-driven output pulley and can be provided with appropriate threads. Therefore, the adjustment can be effected outside the housing.
In another preferred development, the belt is in the form of a toothed belt which engages corresponding teeth of the drive pulley or motor output shaft, or of the output pulley. Thus, no problems arise in the necessary securing of the belt engagement, and the plate need not be adjusted.
The low-maintenance requirement and the device structure providing for the adjustment of the threshold value are taken into consideration by providing the housing with a housing frame component and a second component which holds the drive unit and is connected by a guide to the frame in which said housing component is movable between an operating position, in which the motor is mechanically connected to the door, and a disconnected position in which the mechanical connection is disengaged.
In the event of a malfunction in the drive unit, according to the invention, the mechanical connection of said unit with the door can be discontinued without disassembling the drive unit since the drive unit remains in the guide on disconnection and remains connected to the frame component of the housing. The shift in the guide between the operating position and the disconnected position is simple so that it can be effected by an unskilled person. Consequently, even an unskilled person can move the door manually on occurrence of a fault, without waiting for a specialist, and without the risk of damage to the mechanical connection between the door and the motor when the force is applied in the direction opposite to that of normal operation.
As a result of the shiftability of the drive unit in the guide, according to the invention, the specialist can effect repairs without disassembling the drive unit. When, at least some of the parts of the units must be changed, the unit or the intermediate housing is removed from the guides. Therefore, repair and possible prescribed maintenance are considerably simpler.
In an especially preferred embodiment of the invention, the electric power supply is interrupted when the drive is shifted in the guides for the mechanical disconnection. This provision reduces the risk of damage to the drive unit due to continued current supply in case of malfunction, and makes it possible for the specialist to conduct maintenance or repairs without risk of electrical shocks, unanticipated short circuits, or the like.
Another preferred embodiment provides for the separation of at least the mechanical connection in a first disconnection step, and then for a second disconnection step for the motor drive unit, in which the housing cover is removed. Thus, in the event of a malfunction, an unskilled person can move the door manually, and then the drive unit is made accessible to a specialist in the second disconnection step.
In still another advantageous development, the connection and/or the intermediate housing component and, optionally, also the frame component are made of elastic plastic material to avoid the transmission of vibrations, caused by the motor or the stepdown transmission, to the door acting as resonator, or the fixed portion of the housing.
These and further objects, features and advantages of the present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, several embodiments in accordance with the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic perspective view of a door with a drive of the type to which the present invention is directed;
FIG. 2 is a partial horizontal sectional view of a motor drive unit as in FIG. 1, in accordance with a first embodiment of the invention, with FIG. 2a being a sectional view taken along line A--A of FIG. 2;
FIG. 3 is a horizontal sectional view of the motor drive unit as in FIG. 1, in accordance with a second embodiment of the invention;
FIG. 4 is a sectional view along line IV--IV in FIG. 3;
FIG. 5 is a cross section of the drive motor unit of FIG. 1, in accordance with another embodiment; and
FIG. 6 is a cross section of the motor drive unit of FIG. 1, in accordance with a further embodiment of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
To clarify with an example the application of the drive considered, FIG. 1 is a perspective view of a closed single-panel, up-and-over door. The upper edges of the door 91 are guided on the right and left sides by rollers in horizontal guide rails 92. Guides 94 are provided on the jambs 93 for additional guidance of the door.
A carriage 95 is pivotably connected to the door and longitudinally movable along a rail 96 parallel to guide rails 92. Carriage 95 is attached to an endless chain 97 which passes over a deflecting sprocket at the door end of rail 96, and a drive sprocket that is driven by drive unit 98 at the other end of rail 96. In the embodiments of FIGS. 5 and 6, the drive sprocket is designated by numeral 56 and driven by an output pulley 55 in said figures, or 7 in FIG. 2. A similar arrangement is utilized, but not shown, with respect to the FIG. 3 embodiment.
In the first embodiment represented in FIG. 2, a two-part housing for drive unit 98, which contains the motor, the plate and the chain drive sprocket by means which are not represented, appears only as its frame component 1. The motor (not shown), which drives a belt drive pulley 2, is fixed to said frame component 1. A plate 4 is pivotally mounted on a pin 3 that extends parallel to and axially spaced from belt drive pulley 2. The plate 4 carries two belt guide pulleys 5 and 6, which are in contact with the outside surface of the two portions of a belt 8 that extends from belt drive pulley 2 to the output pulley 7. The two belt portions are, thus, held mutually out of line so that, when the motor is running and the speed of output pulley 7 is braked by an obstacle, said pulley deflects plate 4, in a manner determined by the belt portion that is tensioned in accordance with the direction of rotation, by forcing outward the belt guide pulley 5 or 6 concerned. The braking of output pulley 7, relative to the speed of drive pulley 2, is caused by an obstacle in the path of motion of the door since the door motion is reduced accordingly, and transmitted to output pulley 7 by the chain.
On each of opposite sides of the plate 4, a respective one of two-armed springs 9 and 10 is retained on a respective one of pins 11 and 12, which are fixed to the housing. One spring arm, 13 or 14, is in contact with a respective side of the plate 4, and the other spring arm, 15 or 16, is in contact with an inner face of the setscrew 17 or 18, which is engaged in a threaded hole, 19 or 20, in a wall of the frame component 1. The spreading motion of the two-armed springs is limited by stops 21, which are in contact with the arms.
Near the middle, widthwise of the portion of plate 4 disposed on the side opposite to that receiving pin 3 and closest to output pulley 7, an extension 22 is provided. The extension 22 carries a shield part generally designated by numeral 23. This shield part comprises two elements 24 and 25 in the form of projections oriented substantially at a right angle to the bottom plane of frame 1. Observed from the top, these projections end a short distance from the beam path of a photoelectric cell 26, which is located between the screen elements 24, 25 when the plate is in the illustrated central position, and whose beam is not interrupted in this condition, which is the normal operating condition, and in which control switch contacts are closed.
As clearly apparent, especially in the drawing, the load applied by two-armed springs 9 and 10 on the sides of plate 4 can be finely adjusted by turning setscrews 17 and 18. The load force determines the threshold value of the belt tension. When this value is exceeded, plate 4 is deflected to the right or to the left, depending on the belt direction of motion, and the right or left screen element 24 or 25 penetrates the beam of the photoelectric cell, and, therefore, stops or reverses the motor. For this purpose, optical switching means (not shown) are placed beyond the photoelectric cell. While, in the illustrated embodiment, beam interruption is produced by one of vertically oriented shield elements passing between transmitter and receiver parts 26a, 26b of cell 26, horizontal shield parts passing between transmitter and receiver parts located above and below same may also be utilized.
The belt is provided with internal teeth (not shown) which engage the corresponding teeth of belt drive pulley 2 and output pulley 7. Since no slip can then develop, the belt tension need not be adjusted, for example, by varying the distance from plate 4.
In the embodiment of FIGS. 3 and 4, the portion of the motor drive to which the provisions and preferred structures of the invention refer are represented. In addition, basically similar developments derived therefrom can be adopted, such as those disclosed in the embodiment of German Gebrauchsmuster (Utility Model) No. 7,817,731, reference to which is made here is this respect. In principle, it is certainly possible also to construct a door drive provided with the characteristic features determining the present form, so that the drive belt, or, for example, a chain or a pulling means, moves the door directly.
As with the first embodiment, in this embodiment, drive belt 8 extends around a drive shaft or drive pulley and an output pulley, and between a pair of guide pulleys. In this embodiment, the drive shaft is designated 27, the guide pulleys 29 and 30, and the output pulley equivalent to pulley 7 of the first embodiment is not shown. The pair of belt guide pulleys 29 and 30 form the ends of two free arms of a sort of triangular configuration whose vertex is the belt drive shaft 27, or can be a pulley which is attached coaxially on the output shaft of the drive motor unit as in the first embodiment.
Similar to the object of the above-cited Gebrauchsmuster, belt guide pulleys 29 and 30 are mounted on a plate 28 which is pivotably mounted on a shaft 31 that is parallel to drive shaft 27. In this case, the two guide pulleys are placed on arms 28a which extend on both sides of the output shaft. Plate 28 consists of a root piece, at the base end of the plate that is pivotable about shaft 31, the two arms 28a carrying guide pulleys 29 and 30, which form fork portions branching from the root piece, and an extension 32 which, in the present embodiment, extends away from shafts 31 and 27 in a straight line on a connector portion 28b located between arms 28a, and because the ends of the fork arms 28a, carrying guide pulleys 29 and 30, are so connected with each other, a plate is formed which is provided with an opening 28c in which output shaft 27 is placed and can move freely, even with maximum swinging of the plate.
As apparent from the drawing, the actuators 35 and 36 of switches 37 and 38 engage the lateral surfaces of the extension 32 practically without play in such a manner that one of switches 37, 38 is actuated when plate 28 is deflected in one direction, and the other switch when the plate is deflected in the other direction. As determined by the structural form, actuators 35 and 36 can actuate the switches directly or indirectly. The actuators are held stationary in the represented inactive position by the load force of one of the related coil springs 39 and 40. Thus, each actuator can be moved with movement of extension 32 toward it and its associated one of the switches, but does not follow extension 32 when movement of the plate 28 shifts it from the position shown toward the other of the switches 37, 38.
Each switch 37, 38 cooperates with one actuator 35, 36, which actuator is pressed by a spring 39 or 40 of each switching unit. The rear ends of the springs 39, 40, i.e., the ends away from extension 32, are in contact with adjusting means 42 and 41. The adjusting means are in the form of cams which are rotatable about screws in the direction indicated by arrows in the drawing. In regard to each screw and related axis of rotation, the cam surfaces are in the form of spirals, so that, for different positions of the cams, the distance between the axis of rotation and the rear end of the corresponding spring can be adjusted accordingly. Therefore, a highly precise, easily effected, continuously variable adjustment of the spring load is obtained. Thus, the nominal value of the belt load for which the plate and, therefore, extension 32 can be deflected and carry along actuators 35 and 36 against the preset force of springs 39 and 40, can be adapted to occurring usage conditions.
The two switches 37, 38 with related actuators 35, 36, springs 39, 40 and adjusting means 41, 42, are advantageously made in identical form for both sides of extension 32. The parts that are associated with each other are preassembled on a support plate 43 or 44 as units that may be mounted at either side of extension 32 by merely rotating same by 180°, thereby contributing to favorable manufacturing considerations. Individually actuated adjusting means 41 and 42 permit the consideration of different faults in the door opening and closing motions, despite the identicality of the switch units.
In the two directions of motion, different threshold values may be introduced for obstacles triggering accident-responding disconnection. Therefore, beside the exact adjustment based on the limited play or no-play switching arrangement cooperating with the extension in normal operation, the structure of the invention for the door operator is such that malfunctions in the motion processes do not result in corresponding pendulum motions of the plate, so that the system can be unstable in normal operation, yet false indications or simulations of the presence of an obstacle will not result in the accident-responsive disconnection of the drive being produced.
Since the belt tension is another factor in the regulation of the entire system, this tension is adjustable. This condition is simply obtained by securing the shaft 31, about which plate 28 is pivotable, to a support plate 45 which is adjustable by bolt and slot connections 46 and 47, so that the distance between drive shaft 27 and the shafts of belt guide pulleys 29 and 30 is adjustable. To effect as much as possible the same adjustment for the two belt portions, the slots 46a, 47a are parallel to the bisector of the vertex angle of the triangle formed by drive shaft 27 (vertex) and the two pulleys 39 and 30 (free legs). Since extension 32 is also oriented in this direction, when the shifting of the bolts 46b, 47b in the slots 46a, 47a is exactly straight, there is no variation in the application of extension 32 on actuators 35 and 36. To obtain such a straight shift, support plate 45 is provided with an additional slot 48 which is in line with the noted bisector and engaged by a guide pin 49. As a result of this, a three-point attachment of support plate 45 and plate 28 mounted thereon is achieved, and they can be moved only in the direction of the slots. Thus, they can be fixed in different positions as determined by the desired tension of belt 8 or at equivalent distances between output shaft 27 and belt guide pulleys 29 and 30, without affecting the interaction between extension 32 and the switch units.
FIG. 5 is a view partly in section of one embodiment of a door operator with a pulling chain drive.
FIG. 6 is a view partly in section of another embodiment of such a door operator.
In the embodiments of FIGS. 5 and 6, a housing generally designated by numeral 51 contains a drive motor 52 connected to a clutch, generally designated by numeral 57, by a step-down transmission 53 consisting of two V-belt pulleys 54 and 55 interconnected by a V-belt 8'. The smaller pulley 54 constitutes the rotor of the motor and larger pulley 55 is coaxial with a drive sprocket 56. Sprocket 56 engages a chain (simply represented by a dot-and-dash line) which is guided along a rail 58. In a manner such as shown in FIG. 1, a return sprocket is arranged at the other end of the rail, so that the chain extends continuously between the two sprockets and is connected to a door. Depending on the direction of rotation of motor 52, the pulling member reciprocates on one of the portions of the chain between two positions. The door is closed in one position, and open in the other position.
Housing 51 consists of a frame component 58, a second component 59, and a cover 60. At least the second housing component is made of vibration-damping material. Frame component 58 is provided with brackets 61 to fix the housing in position, for example, on a garage ceiling 62. A bearing 63 for the shaft 64 of output sprocket 56 is provided on the inside surface of frame component 58. A part of a guide generally designated by numeral 65, on which second housing component 59 is connected to frame component 58, is fixed to or built into the bottom of frame component 58.
In the embodiment of FIG. 5, four guides 65 are arranged at right angles to frame 58. In the partial section shown, only two of these guides are visible. Each of the guides comprises a projection 66, formed on the bottom of frame component 58, which extends perpendicularly to said bottom, and in which an elongated slot 67 is formed. On second housing component 59, extensions 68 are directed toward the bottom of frame component 58. The ends of the extensions proximate to the bottom are provided with pins 69 which penetrate slots 67. Thus, second housing component 59 can be moved in the direction of slots 67 relative to frame component 58, between two end positions. The position in which second housing component 59 is closest to frame component 58 is the operating position, as apparent from the drawing.
Drive motor 52 and step-down transmission 53 are mounted in second housing component 59. One half 70 of clutch 57 is keyed to the shaft of drive pulley 55. The dogs 71 of the said clutch half engage corresponding recesses in the other clutch half 72 which is keyed to output pulley 56. At least the contact surfaces of the clutch are made of vibration-damping material. In this operating position, the shaft of motor 52 is mechanically connected to output pulley 56 by step-down transmission 53 and belt 8 (see FIGS. 1-4) and clutch 57, so that the chain of the pulling chain drive is moved. In this regard, it is intended that pulley 55 correspond to pulley 7 and pulley 54 to either pulley 2 or shaft 27, with the corresponding malfunction switching arrangement interposed therebetween, the latter being omitted from FIGS. 5, 6 for ease in illustration only. The frame component 1 in FIGS. 2 and 3 may be a part of second component 59 in FIGS. 5 and 6.
Housing cover 60 and second housing component 59 are provided with aligned holes into which a screw 73 is introduced. The end of said screw projecting from cover 60 is provided with a knob 74, and the other end thereof engages a thread 75 formed in the bottom of frame component 58.
When screw 73 is rotated out of thread 75, the pins 69 of second housing component 59 move in slots 67 to a position of the slot connection for which second housing component 59 is separated by the maximum distance from frame bottom 58. The drive elements mounted on second housing component 59, specifically motor 52, step-down transmission 53, and clutch half 70 also move away with the said component, so that the dogs 71 of clutch half 70 move out of the recesses in clutch half 72. Therefore, the motor is mechanically separated from output pulley 56 which can rotate freely as the chain is moved on manual operation of the door. In this uncoupled position, the two halves 86 and 87 of an electric plug connection 85 joining the electric supply lines 88, and possible control lines, are separated. As shown in FIG. 6, control circuits 76 can be provided in second housing component 59. In any case, the electric plug connection 85 is closed or opened with engagement and disengagement of clutch 57, when second housing component 59 is moved in guide 65 between the operating position and the disconnected position. Therefore, the electric elements mounted in housing component 59 are not supplied current when second housing component 59 has been moved to the disconnected position.
When screw 73 has been moved completely out of thread 75, it can be pulled through the hole (not shown) in second housing component 59, and cover 60 can be removed from the housing. In this position, the parts of the drive unit are accessible without risk since the current supply has been interrupted on separation of the electric plug connection. Clutch 57 is also disengaged, so that the moving parts of the drive unit can be easily rotated manually, for example, for maintenance.
The length of the distance of engagement of screw 73 in thread 75 can be determined so that clutch 57 is disengaged after screw 73 has been rotated a first distance out of thread 75, so that, in the event of a malfunction in the drive unit, the door can be moved manually as previously disclosed. Screw 73 is fully released after further rotation, so that cover 60 can be removed.
In the embodiment represented in FIG. 6, only the structure of guide 65 between frame component 58 and second housing component 59 has been modified, the other elements being identical, so that reference can be made to the appropriate description of the embodiment of FIG. 5.
In the embodiment represented in FIG. 6, two projecting bearing brackets 77 and 78 are provided in frame component 58. Bracket 78 carries a pivot bearing with a pin 79 about which one end 80 of second housing component 59 is pivotable. Opposite bearing bracket 77, second housing component 59 is provided with a support bracket 81 which engages bearing bracket 77 so that holes present in the two brackets can be aligned. Then a pin, retaining rod, or the like (not shown) can be removably introduced into the holes through an opening in the cover 60 as will be readily apparent to be skilled artisan. to prevent the pivoting of second housing component 59 in the indicated operating position. In this operating position, the halves 70 and 72 of clutch 57 are engaged and the drive motion of motor 52 is transmitted to output pulley 56.
When the connection between bearing bracket 77 and support bracket 81 is separated, second housing component 59 can be pivoted about pin 79, so that clutch 57 is disengaged. In this disconnecting motion, i.e., in the transition from the operating position to the disconnected position (not shown), an electric plug connection is acted upon so as to be coupled in the operating position represented, and moved to the disconnected position on pivoting of second housing component 59 about pin 79. Thus, the resulting conditions are the same as those disclosed in reference to FIG. 5.
In the present case, two successive separate operating phases can be provided for, for example, by uncoupling the connection between bearing bracket 77 and support bracket 81 while cover 60 is closed, second housing component 59 being subsequently moved to the disconnected position. In conditions which are not represented, the housing can be removed only by a specialist to provide for the accessibility of the drive unit for repairs and maintenance.
When the drive unit or parts thereof must be replaced, the pins 69 of the slot connections in the embodiment of FIG. 5, or the pivot pin 79 in the embodiment of FIG. 6, can be removed by taking simple locking means holding the pins in position out of their engagement position, so that second housing component 59 can be totally removed from frame component 58. Naturally, other disconnecting means may be provided, depending on the structure of the guide. The same remark applies to the structure of other components and elements.
While I have shown and described various embodiments in accordance with the present invention, it is understood that the same is not limited thereto, but is susceptible of numerous changes and modifications as known to those skilled in the art and I, therefore, do not wish to be limited to the details shown and described herein, but intend to cover all such changes and modifications as are encompassed by the scope of the appended claims. | A door operated drive assembly comprising an electric drive motor mechanically connected to a door pulling device by a transmission in the form of a belt drive or the like, utilizes an extension of a plate that is swingable in response to deviations of application pressure of the drive belt on belt guide pulleys carried thereby to trigger a switching arrangement utilized to trigger stopping or reversal of the drive motor. In order to make actuation of the switching arrangement a function of the degree of pressure applied by the drive belt, the plate is elastically loaded toward a middle position of its range of swingable movement. The elastic loading of the plate in accordance with a first embodiment is by way of two-arm springs positioned at opposite sides thereof, and in a second embodiment is produced by helical springs which act via actuators, on opposite sides of the plate extension. In both embodiments, the extension reaches to a position adjacent the switching arrangement, but, in the first embodiment, the extension comprises a pair of shields and the switching arrangement comprises a single photoelectric arrangement disposed therebetween, while, in the second embodiment, the extension is a straight projecting arm and the switching arrangement is a pair of switches disposed at opposite sides thereof. In accordance with a feature common to either embodiment, the drive arrangement is mounted in a multiple-component housing that comprises two components which are shiftable relative to each other between an operating position in which the drive motor is mechanically connected to a door pulley means, and a disconnected position in which the mechanical connection is interrupted. | 4 |
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority of European Patent Office Application No. 08013174.1 EP filed Jul. 22, 2008, which is incorporated by reference herein in its entirety.
FIELD OF INVENTION
[0002] This invention relates to signal processing in pulse-echo measurement system such as level measuring systems. The invention will be particularly described with reference to measuring the level of flowable materials within a container by microwave pulse-echo techniques, but is equally applicable to other contexts such as acoustic pulse-echo measurement.
BACKGROUND OF INVENTION
[0003] In systems of this nature, the echo profile typically contains a number of false echoes arising from obstacles, reflections and the like. It is well known to provide signal processing which discriminates between these and the true measurement echo. Many systems make use of a time-varying threshold (TVT). The echo of the material sometimes dips below the TVT causing the device to select another echo and potentially go into loss of echo state. There are also instances where an unwanted echo rises above the TVT, causing the device to lock onto that echo and produce incorrect readings.
[0004] Up to now, the echo has been tracked by a simple discrimination window: the next echo must fall within the window to be accepted. The window is centred on the position of the current echo, and has its width adjusted based on historical knowledge. The window is initially narrow, and an echo within the window is selected. When no echoes are found within the present window, the size of the window is increased until an echo falls within it.
[0005] Unwanted echoes are eliminated from the selection process by the TVT curve. At commissioning, the TVT is shaped around the known fixed obstacles. Once the commissioning is complete, the device no longer has any means to discriminate for obstacles. If the level of an echo from an obstacle rises above the TVT, then the device will lock onto it when the level of the material is below the level of the obstacle. This can be a significant problem, which the present invention seeks to overcome or mitigate.
REFERENCES
[0000]
[1] H Leung, Z Hu, and M Blanchette, “Evaluation of multiple radar target trackers in stressful environments”, IEEE Transactions on Aerospace and Electronic Systems, vol 35, pp 663-674, April 1999.
[2] S S Blackman, “Multiple-Target Tracking with Radar Applications”, Norwood, M A, Artech House, 1986
[3] Y Bar-Shalom and T E Fortmann, “Tracking and Data Association”, San Diego, Calif., Academic Press, 1988.
SUMMARY OF INVENTION
[0009] The invention provides a method of processing echo signals in a pulse-echo measurement system where obstacles are likely to cause false echoes, the method comprising:
[0010] forming tracks of multiple received echoes;
[0011] using a recursive filter, such as a Kalman filter, to monitor each track by estimating a track velocity and predicting the position of the next echo;
[0012] selecting one echo from the multiple echoes received at any given time by selecting the echo on that track which has a non-null velocity and is closest to the transmitter or, if all tracks have a null velocity, that which is closest to the transmitter.
[0013] This enables the moving target to be identified amongst the clutter of echoes from obstacles.
[0014] A track may conveniently be initiated when a set of three points have a similar velocity. Optionally, it is also advantageous that said track is not initiated if the set of three points have accelerations which differ by more than a predetermined amount.
[0015] Preferably a track is deleted when no measurement update has occurred on that track for a predetermined period of time. This reduces the amount of data to be handled.
[0016] Preferably also each track is updated by a gating procedure, using a gate of predetermined width centered on a predicted track position, this again being an efficient means of maintaining the track.
[0017] In order to further simplify data processing, the method preferably includes discriminating between multiple candidates on a single track by use of a nearest neighbour procedure, which most conveniently comprises forming an assignment matrix, and applying to the assignment matrix a suboptimal solution comprising the steps:
[0018] (1) Search the assignment matrix for the closest (minimum distance) measurement-to-track pair and make the indicated assignment.
[0019] (2) Remove the measurement-to-track pair identified above from the assignment matrix and repeat Rule 1 for the reduced matrix.
[0020] The method of the present invention is preferably carried out in software. Accordingly, the present invention also provides a computer program with a computer readable program code for carrying out the foregoing method, and a computer program product (such as a storage medium) for implementing the method, when the program code is run on a computer.
[0021] The invention also provides a pulse-echo measurement system including signal processing means, the signal processing means being operable to discriminate against false echoes caused by obstructions by carrying out the foregoing method. The signal processing means preferably comprises computer program storage means comprising the foregoing computer program.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] An embodiment of the invention will now be described, by way of example only, with reference to the drawings, in which:
[0023] FIG. 1 is a schematic block diagram of a pulse-echo measurement system;
[0024] FIG. 2 is a graphical representation of a sequence of measurements in such a system, where multiple echoes are present at times;
[0025] FIG. 3 is a similar representation illustrating measurements being assigned to tracks;
[0026] FIG. 4 represents results obtained in an experiment in which a tank is filled and emptied;
[0027] FIG. 5 and FIG. 6 show filter estimates of the position and velocity, respectively, of the measurements of FIG. 4 ; and
[0028] FIG. 7 shows the selection of echoes from the results of FIG. 4 .
DETAILED DESCRIPTION OF INVENTION
[0029] Referring to FIG. 1 , a radar or ultrasonic transmitter 1 transmits an interrogating pulse into a storage vessel 2 . A captured echo signal 3 is applied to a signal processing circuit 4 as an example of signal processing means in which the echo signal is digitised and processed as will now be described.
[0030] The invention is based on a recursive filter such as a Kalman filter to track all echoes above the TVT, and even some echoes, specially selected that may fall below the TVT. Each echo constitutes a track and each track is monitored by a Kalman filter. For each track the method estimates the velocity and predicts the position of the next echo.
[0031] In cases where a fixed obstacle would rise above the TVT, a null velocity is assigned to that track and that echo is not selected if there is another track that has a non-null velocity. In other words, the method prefers to pick a moving echo rather than a stationary echo.
[0032] Track Initialization and Track Deletion
[0033] The method has the ability to add tracks when a new echo is detected, and the ability to delete tracks when there is no echo in the expected area of the profile.
[0034] A track is initialized when a set of three points jointly satisfy the velocity test and the acceleration test. The velocity test focuses the associations of points that have a similar velocity, and a smaller acceleration. The acceleration test prevents the association of a point to a track that would be too far. The velocity test initializes tentative tracks while the acceleration test confirms them. The criteria for velocity and acceleration can be adjusted for each application types.
[0035] The following example illustrates the track initialization process.
[0036] In each of FIGS. 2-4 and 6 there is shown a series of snapshots taken at time intervals k, with each measurement made in any snapshot being denoted by the symbol *.
[0037] FIG. 2 shows a series of snapshots of detected echoes taken at time intervals k. The sequence of measurements depicted in FIG. 2 is given in Table 1.
[0000]
TABLE 1
k = 1
k = 2
k = 3
y k 1
310.01
3173.8
1115.9
y k 2
N/A
2885.9
353.2
y k 3
N/A
2036.9
N/A
y k 4
N/A
324.4
N/A
m(k)
1
4
2
[0038] The following steps are then carried out.
[0039] 1. Conduct the velocity test for each pair of (unassociated) measurement in snapshot k−1 and snapshot k−2. That is,
[0000]
v
min
≤
(
y
k
-
1
j
-
y
k
-
2
i
)
T
k
-
1
≤
v
max
(
1
)
[0000] where 0≦v min and 0≦v max ≦v max . Pairs with velocities greater than v min but less than v max are declared as tentative tracks. If k=3 and T 2 =1 sec. in FIG. 2 , one would compute (see Table 1)
[0000]
(
y
2
1
-
y
1
1
)
T
2
=
3173.8
-
310.01
1
=
2863.8
mm
/
sec
.
(
y
2
2
-
y
1
1
)
T
2
=
2885.9
-
310.01
1
=
2575.9
mm
/
sec
.
(
2
)
(
y
2
3
-
y
1
1
)
T
2
=
2036.9
-
310.01
1
=
1726.9
mm
/
sec
.
(
y
2
4
-
y
1
1
)
T
2
=
324.4
-
310.01
1
=
14.4
mm
/
sec
.
(
3
)
[0000] if v min =0 mm/sec. and v max =20 mm/sec., (y 1 1 ,y 2 4 ) would be the only pair of measurements satisfying equation (1). Hence, it would be the only pair of measurements that form a tentative track.
[0040] 2. For every tentative track consisting of two measurements, perform track confirmation via an acceleration test with {y k n } n=1 m(k) ={y k 1 , . . . , y k m(k) } That is,
[0000]
(
(
y
k
n
-
y
~
k
-
1
j
)
T
k
-
(
y
~
k
-
1
j
-
y
~
k
-
2
i
)
T
k
-
1
)
≤
T
k
a
max
(
4
)
[0000] where “˜” indicates the tentative track obtained in the previous test. For FIG. 2 assuming T 3 =1 sec., one would compute (see Table 1)
[0000]
(
(
y
3
1
-
y
~
2
4
)
T
3
-
(
y
~
2
4
-
y
~
1
1
)
T
2
)
=
1115.9
-
324.4
1
-
14.4
=
777.1
mm
/
sec
2
(
(
y
3
2
-
y
~
2
4
)
T
3
-
(
y
~
2
4
-
y
~
1
1
)
T
2
)
=
353.2
-
324.4
1
-
14.4
=
14.4
mm
/
sec
2
[0041] if a max =20 mm/sec 2 , (y 1 1 ,y 2 4 ,y 3 2 ) would be the final confirmed track.
[0042] We stress that measurements not associated with any track, and those unused from previous tests, are used to search for new potential tracks as outlined above. So it should be understood that the initiation procedure is applied in a sliding window to the set of unassociated measurements.
[0043] Track Maintenance
[0044] FIG. 3 shows a typical sequence of measurements to illustrate a procedure of track maintenance.
[0045] To set the stage for a detailed discussion, assume that N tracks have been formed by the previous snapshot. Now, at snapshot k, we receive a new set of measurements {y k n } n=1 m(k) to update established tracks. The immediate question of interest is this: what are the measurements we use to update each track? In multi-target tracking systems, this is the so-called “data association” problem. The classical answer is to use “gating” and an appropriate solution to the assignment matrix problem [2].
[0046] For an illustration, see FIG. 3 where there are seven measurements {y 6 n } n=1 7 at snapshot 6 , but only two established tracks at snapshot 5 .
[0047] Gating
[0048] Gating is a technique which reduces the number of candidate measurements for an established track. At snapshot k, we construct for each target a gate in the region where the measurement is expected to lie. The gate is centered at the predicted measurement ŷy n j , and only those measurements lying within this gate are considered for track update. Defining d k j,i to be the distance function for associating measurement y k i to track j at snapshot k, the gating test can be written as
[0000]
d
k
j
,
i
=
(
y
k
i
-
y
^
k
j
)
2
S
k
j
≤
γ
(
5
)
[0000] where ŷ k j is the predicted measurement for track j, S k j is the average MSE (mean square error) for estimate ŷ k j , and γ is a number generally chosen between 16 and 25 [1, 2, 3]. If d k j,i ≦γ, y k j is a candidate measurement for track j. Conversely, if d k j,i ≧γ, y k i is not a candidate measurement for track j. If a measurement is not associated with any track, then we call it an unassociated measurement. As discussed in the previous section, all unassociated measurements are considered for track initiation.
[0049] A track could have multiple candidate measurements. An additional procedure must be carried out to assign a measurement y k i to a particular track. Traditionally, there are two approaches to solve this problem. They are “nearest-neighbour” (NN) approach and the “all-neighbour” approach. The NN approach is less computationally demanding than the all-neighbour approach. For multi-target tracking in limited clutter, it represents a good tradeoff between complexity and performance [1]. For this reason, we use a nearest neighbour (NN) approach to assign a measurement y k i to a particular track.
[0050] Suboptimal Solution to the Data Association Matrix Problem
[0051] The NN approach is based on a solution to the assignment matrix problem. In general, the assignment matrix, for N established tracks and m(k) measurements at snapshot k, is given by Table 2.
[0000]
TABLE 2
Meas.
Tracks
y k 1
y k 2
. . .
y k m(k)−1
y k m(k)
Track 1
d k 1,1
d k 1,2
. . .
d k 1,m(k)−1
d k 1,m(k)
Track 2
d k 2,1
d k 2,2
. . .
d k 2,m(k)−1
d k 2,m(k)
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
Track N − 1
d k N−1,1
d k N−1,2
. . .
d k N−1,m(k)−1
d k N−1,m(k)
Track N
d k N,1
d k N,2
. . .
d k N,m(k)−1
d k N,m(k)
[0052] The desired (optimal) NN solution to the assignment matrix problem is one that maximizes the number of measurement-to-track pairing, while minimizing the total summed distances [2].
[0053] For very small N and m(k), we can find the optimal solution through simple enumeration. But for N significantly greater than 1 and m(k) significantly greater than 1, simple enumeration is far too time consuming to find the optimal solution. For this reason, researchers have suggested the use of Munkres algorithm to find the optimal solution [1,2].
[0054] Munkres algorithm is an efficient algorithm, but the required computational demands may still preclude its implementation on a dedicated DSP processor. In response to this, several suboptimal algorithms have been proposed in the literature. They do not guarantee optimality of the solution, but they are computationally attractive, and appealing to intuition. For scenarios with limited clutter, they often yield solutions that are often close to the optimal solution. The rules for one such suboptimal solution are shown below [1,2].
[0055] Suboptimal Solution to the Assignment Matrix Problem
[0056] Search the assignment matrix for the closest (minimum distance) measurement-to-track pair and make the indicated assignment.
[0057] Remove the measurement-to-track pair identified above from the assignment matrix and repeat Rule 1 for the reduced matrix.
[0058] In the following, we will adopt this approach to solve the assignment matrix problem. For this reason, we have effectively proposed an implementation of the NN filter.
[0059] Example of Gating and the Suboptimal Solution to the Assignment Matrix Problem
[0060] For the scenario depicted in FIG. 3 , we can at k=6, choose between seven measurements {y 6 n } n=1 7 to update the tracks. To reduce the number of candidate measurements for each track, we must first calculate (5) for all y 6 n . Evidently, y 6 1 , y 6 2 , and y 6 3 will not satisfy the gating test for either tracks, i.e., d 6 1,f ≧γ and d 6 2,i ≧γ for i=1, 2, 3. To reflect this outcome, we assign to their associated distance functions. That is,
[0000] d 6 1,i =∞ (6)
[0000] d 6 2,i =∞ (7)
[0000] for i=1, 2, 3. For the remaining measurements which satisfy at least one of the gates specified by (5), we assume the following hypothetical values for
[0000] d 6 1,4 ==2.2 d 6 2,4 =√ (8)
[0000] d 6 1,5 =1 d 6 2,5 =∞ (9)
[0000] d 6 1,6 =2 d 6 2,6 =1.5 (10)
[0000] d 6 1,7 =∞ d 6 2,7 =0.5 (11)
[0061] Then, according to Table 2, the corresponding data association matrix can be written as
[0000]
Meas.
Tracks
y 6 1
y 6 2
y 6 3
y 6 4
y 6 5
y 6 6
y 6 7
Track 1
∞
∞
∞
2.2
1
2
∞
Track 2
∞
∞
∞
∞
∞
1.5
0.5
[0062] For data association (see suboptimal solution), y 6 7 is first assigned to track 2, then y 6 5 is assigned to track 1, but y 6 4 and y 6 6 are left without any assignment. Thus, y 6 4 and y 6 6 are both unassociated measurements.
[0063] Finally, we stress that the NN filter finds a unique pairing for each track. At most, one measurement can be used to update each track. With a measurement assigned to a particular track, we run the standard Kalman filter update equations to update that track.
[0064] Track Deletion
[0065] Tracks with no measurement updates are deleted. If the gate of track j is empty for N del consecutive snapshots, track j is deleted. In this work, we choose N del =1, so that we may minimize the complexity of the algorithm.
[0066] We can add robustness to the track deletion to delay the deletion after m consecutive gates come up empty.
[0067] Also, we can look for echoes that would have fallen below the TVT but that are within the gate. This would add significant robustness to echo level that may dip just below the TVT.
EXAMPLE
[0068] An example of the invention in the form of an experimental filling and emptying of a tank will now be described.
[0069] A tank containing obstructions was filled with kerosene and emptied. FIG. 4 shows the resulting sequence of measured echo profile. FIG. 5 shows the position and velocity estimates of the peaks of the measured echo profiles. Velocity estimates are based on sampling interval of T k =1 sec.
[0070] FIG. 7 shows the selected echo for the sequence of measured echo profiles, the selected echo being shown by a solid line.
[0071] Clearly, the NN filter accurately estimates the position and the velocity of the peaks of the measured echo profile. The echo for the pending TOF (time of flight) calculation is also correctly chosen.
[0072] Modifications may be made to the foregoing embodiment. Instead of using a Kalman filter, other forms of recursive filter may be used. Other procedures may be used for initiating, maintaining and deleting tracks; for example, techniques other than nearest neighbour and gating may be sued for assigning echoes to tracks.
[0073] The main advantage of the invention is to be able to identify the moving target amongst the clutter of echoes from obstacles. The device becomes immune to echoes from obstacles that may rise above the TVT. Furthermore, the device will not lose an echo that may fall below the detection threshold, or even below the TVT. | Pulse echo signals containing false echoes are processed by forming tracks of multiple received echoes and monitoring these tracks by a recursive filter such as a Kalman filter. A track velocity is estimated for each track, and the position of each the next echo on the track is predicted. | 6 |
BACKGROUND OF THE INVENTION
The present invention relates to a centrifugal compressor such as an exhaust gas turbine supercharger or the like, and more particularly to a diffuser device disposed in a passageway between an air outlet of an impeller and a swirl chamber within a casing in such a centrifugal compressor and a method for manufacturing the diffuser device.
One example of an essential structure on the blower side of an exhaust gas turbine supercharger in the prior art is illustrated in cross-section in FIG. 1. In the structure shown in FIG. 1, externally supplied fresh air is compressed by front blades 5 and an impeller 6 mounted on a rotor shaft 7 which is in turn driven by an exhaust gas turbine, and then an air flow having a pressure and a flow rate required by a diesel engine is formed by a diffuser device 4' and is supplied to a diesel engine through a swirl chamber formed by an outer volute casing 1 and an inner volute casing 2. The diffuser device 4' is fixedly secured to the inner volute casing 2 by means of bolts 20. The air flow supplied by the supercharger is matched with the pressure and flow rate required by the diesel engine generally by means of the diffuser device 4', front blades 5 and impeller 6, but it is a common practice to achieve fine adjustment by means of the diffuser device 4'. In the illustrated construction, since the diffuser device 4' has an integral structure, varieties of specifications required for the diffuser device 4' are so many that even if calculations matching are conducted with the highest class of electronic computer known at present, normally it is required to prepare diffuser devices 4' having two different specifications close to a desired specification. Increase of the construction time, cost and amount of storage due to the necessity for such diffuser devices will raise the overall cost of a supercharger. Moreover, there is a shortcoming that the preparation of two or more diffuser devices require a relatively large investment.
SUMMARY OF THE INVENTION
It is therefore one object of the present invention to provide a diffuser device in a centrifugal compressor which can achieve required matching of a pressure and a flow rate with only one variety of structure.
Another object of the present invention is to provide a method for manufacturing a diffuser device in a centrifugal compressor, by which an adjustable diffuser device can be easily and accurately assembled, and which method is suitable for mass-production at low cost.
Still another object of the present invention is to provide an adjustable diffuser device in a centrifugal compressor, which includes ganged drive means capable of simultaneously and accurately achieving adjustment of a plurality of diffuser blades.
According to one feature of the present invention, there is provided a diffuser device disposed in a passageway between an air outlet of an impeller and a swirl chamber within a casing in a centrifugal compressor, which diffuser device is divided into a diffuser disc capable of being fixed to the casing and a plurality of diffuser blades adapted to be arranged in the circumferential direction of the diffuser disc, and in which the respective diffuser blades have their one ends fitted in bores drilled in the diffuser disc in the circumferential direction and equal in number to the diffuser blades so as to be freely rotatable about the axies of the bores, whereby the blade angle is made variable.
According to another feature of the present invention, there is provided a method for manufacturing a diffuser device in a centrifugal compressor, consisting of the steps of dividing the diffuser device into a diffuser disc and a plurality of diffuser blades produced separately, forming a cylindrical boss integrally with each of the diffuser blades, fitting the bosses of the respective diffuser blades in bores drilled in the diffuser disc, then adjusting the inlet width and outlet width between the adjacent diffuser blades by means of positioning jigs, and fixing the diffuser blades with respect to the diffuser disc.
BRIEF DESCRIPTION OF THE DRAWINGS
In the accompanying drawings
FIG. 1 is a cross-section view showing one example of an essential structure on the blower side of an exhaust gas turbine supercharger of the prior art,
FIG. 2(a) is a cross-section similar to FIG. 1 of the essential structure on the blower side of an exhaust gas turbine supercharger according to one preferred embodiment of the present invention,
FIG. 2(a) is a sectional view taken along line A--A in FIG. 2(b) as viewed in the direction of the arrows,
FIG. 3(a) is an enlarged cross-section showing the details of the mounting of an adjustment flange and diffuser blades onto a diffuser disc generally illustrated in FIGS. 2(a) and 2(b),
FIG. 3(b) is a plan view of the part of the diffuser divice illustrated in FIG. 3(a),
FIG. 4(a) is a cross-section showing a diffuser device according to another preferred embodiment of the present invention,
FIG. 4(b) is a plan view of the diffuser device illustrated in FIG. 4(a),
FIG. 4(c) is an enlarged side view of a diffuser blade in the diffuser device of FIG. 4(b),
FIG. 4(d) is a cross-section of the diffuser blade taken along line B--B in FIG. 4(c) as viewed in the direction of the arrows,
FIG. 5(a) is a cross-section similar to FIG. 2(a) showing a diffuser device according to still another preferred embodiment of the present invention, in which a ganged drive mechanism for simultaneously adjusting each diffuser blade is included,
FIG. 5(b) is a cross-section taken along line Y--Y in FIG. 5(a) as viewed in the direction of the arrows,
FIG. 6(a) is a diagram showing the geometrical relation between two adjacent sprockets in the preferred embodiment illustrated in FIGS. 5(a) and 5(b),
FIG. 6(b) is a diagram showing the geometrical relation between sprockets and a roller chain in the same preferred embodiment,
FIG. 6(c) is a cross-section taken along line X--X in FIG. 6(b) as viewed in the direction of the arrows,
FIG. 7(a) is a diagram showing the geometrical relation between two alternate sprockets in a ganged drive mechanism for diffuser blades according to yet another preferred embodiment of the present invention,
FIG. 7(b) is a diagram showing the geometrical relation between sprockets and roller chains in the preferred embodiment illustrated in FIG. 7(a), and
FIG. 7(c) is a cross-section taken along line X'--X' in FIG. 7(b) as viewed in the direction of the arrows.
DESCRIPTION OF PREFERRED EMBODIMENTS
The present invention is generally applicable to a centrifugal compressor such as an air compressor, a gas turbine, an exhaust gas turbine supercharger, a gas compressor, a centrifugal pump, etc., but in the following, for convenience of explanation, it will be described in more detail in connection with its preferred embodiments as applied to an exhaust gas turbine supercharger.
In FIGS. 2(a), 2(b), 3(a) and 3(b) which illustrate one preferred embodiment of the present invention, reference numerals 1, 2, 3, 5, 6 and 7 designate the same members as those given like reference numerals in FIG. 1 which shows one example of the prior art structure. In the illustrated structure, the diffuser device 4' provided in the passageway between the impeller 6 and the swirl chamber delimited by the outer volute casing 1 and the inner volute casing 2 in the prior art structure is divided into a diffuser disc 4 mounted on a wall of a similar passageway and diffuser blades 9 adapted to be connected to the diffuser disc 4.
The diffuser blade 9 is provided with a boss 9a on the side of its front edge, and the boss 9a has a positioning pin 13 fixedly secured thereto and a threaded hole formed therein so that a center bolt 12 may be screwed into the hole through a spring washer 15.
An adjustment flange 10 is provided with a cylindrical protrusion having the same diameter as the above-described boss 9a. In the cylindrical protrusion are drilled an appropriate number of positioning bores 13a adapted to have the above-described positioning pin 13 selectively inserted therein, at predetermined intervals in the circumferential direction of the adjustment flange 10, and also at the center of the cylindrical protrusion is drilled a bolt passage bore that is coaxial with the threaded hole in the above-described boss 9a. In the peripheral portion of the adjustment flange 10 are drilled other bores for receiving fixing bolts 11 and parallel pins 14 to be used for relative positioning of the adjustment flange 10 and the diffuser disc 4.
In the diffuser disc 4 is formed a flange receiving bore 41, into which the boss 9a of the diffuser blade 9 and the cylindrical protrusion of the adjustment flange 10 are inserted and opposed to each other. Then, by inserting the positioning pin 13 into a selected positioning bore 13a and fastening the bolts 11 and 12 to fix the relative positions of the adjustment flange 10, diffuser blade 9 and diffuser disc 4, the diffuser blades 9 can be mounted on the diffuser disc 4 at a predetermined mounting angle, that is, so as to have predetermined inlet angle α°, inlet width a and outlet width b as indicated in FIGS. 2(b) and 3(b).
An O-ring 8 is provided in tight contact with the diffuser disc 4 on the side of a thrust bearing therefor in order to prevent leakage of compressed air and vibrations of the diffuser blades 9.
Now a description will be of the operation of the diffuser device constructed as described above. Fresh air is sucked from an inner cylinder side of a guide casing 3, then compressed by the front blades 5, impeller 6 and rotor shaft 7, and further raised in pressure by means of the diffuser disc 4 and the diffuser blades 9. Thereafter the compressed air is supplied at a necessary pressure and a required flow rate to a diesel engine through the swirl chamber delimited by the outer volute casing 1 and the inner volute casing 2.
In the event that it becomes necessary to change the specifications of the diffuser, change of the inlet angle α°, inlet width a and outlet width b can be effected in a simple manner by removing the guide casing 3, drawing the inner volute casing 2 away from the turbine housing 16 a distance of about 5-10 mm, removing the bolts 11 and 12 and spring washer 15 which fix the adjusting flange 10, extracting the positioning pin 13 from the positioning bore 13a located at a reference index point 0 for the inlet angle α° of the diffuser blade 9 and inserting it into another positioning bore 13a located at an adjacent index point +1 or -1 while slightly separating the adjustment flange 10 from the boss 9a, and then assembling the diffuser device in the sequence opposite to the above-described disassembly. In this case, the inner diameter of the array of the diffuser blades 9 serves as a reference for every adjustment.
As will be seen from FIG. 2(b), the pitch θ of the diffuser blades 9 is θ=360°/Z, where Z represents the number of the diffuser blades 9. In the case where the adjustment of the diffuser blades 9 cannot be achieved only be means of the positioning pin 13 and the positioning bores 13a, instead of replacing the diffuser blades 9, adjustment flanges 10 having a different reference value of the inlet angle α o could be prepared and used to replace the previous ones. Then the diffuser device can be reassembled in a simple manner so as to achieve any desired blade angle.
The diffuser device according to the present invention which is constructed as described above has the following advantages. That is, in the event that it becomes necessary to change the specifications of a diffuser device for matching a diesel engine and an exhaust gas turbine supercharger, the necessary specifications of the diffuser device can be achieved in a simple and less expensive manner by replacing inexpensive adjustment flanges and/or selecting new positioning bores, instead of replacing the entire diffuser device or the expensive diffuser blades. In other words, the advantages are as follows:
(1) The cost is low.
(2) Change of the specifications of a diffuser can be achieved in a simple manner by minor disassembly of an exhaust gas turbine supercharger on a diesel engine.
(3) The adjustment flange 10 can be reused.
(4) The inlet angle α°, inlet width a and outlet width b of the diffuser blades 9 can be selectively varied owing to the use of the adjustment flange 10.
(5) Adjustment of the diffuser device can be achieved without completely removing it from an exhaust gas turbine supercharger.
It is to be noted that while the bosses receiving bores 41 were provided on the inner diameter end of the array of diffuser blades in the above-described embodiment, it is also possible to arbitrarily select the positions of the bosses and to effect adjustment in a similar manner to the above-described embodiment by taking the diameter of the selected positions in the array of diffuser blades as a reference However, due to interference with the inner volute casing 2, depending upon the selected reference diameter, sometimes it may happen that change of the specifications cannot be achieved unless the diffuser device is removed from the supercharger.
Now a description will be given with reference to FIGS. 4(a) to 4(d) of a diffuser device according to another preferred embodiment of the present invention in which the blade angle of diffuser blades and accordingly the inlet width and outlet width between diffuser blades is made continuously adjustable without employing the positioning pin 13 as used in the preceding embodiment, and a method for manufacturing the same diffuser device.
In FIGS. 4(a) to 4(d), the diffuser disc 4 is a doughnut-shaped disc with boss receiving bores 41 having a diameter d drilled at an equal pitch along its inner diameter portion in a number equal to the number Z of diffuser blades 9.
Each diffuser blade 9 has an airfoil cross-section associated with a cylindrical boss 9a having a diameter: d centered at the front edge, and it is produced by precision casting or precision forging.
With regard to the configuration of the blade 9, in a diffuser device having a low pressure ratio it has a rectilinear cross-section, while in a diffuser device having an increased pressure ratio and required to have excellent performance it has an airfoil cross-section.
Upon assembly, diffuser blades 9 are assembled by inserting their bosses 9a into the corresponding bores 41 in the diffuser disc 4, and the desired inlet width a and outlet width b are preset by transversely moving the rear edges of the diffuser blades 9, and then, while holding the diffuser blades in this position by means of jigs so as to prevent further movement, brazing of bosses 9a on the diffuser disc 4 and the diffuser blades 9 into the receiving bore 41 bosses 9a is effected within a thermostat or within an argon atmosphere to bond them together, and thereby the desired specifications of the diffuser device can be achieved.
In summary, a diffuser device 4' is produced in the form of a diffuser disc 4 and separate diffuser blades 9, and after the desired inlet angle, outlet angle, inlet width and outlet width have been preset by means of positioning jigs by transversely moving the rear edges of the diffuser blades, the diffuser blades 9 are bonded to the diffuser disc 4.
According to the second preferred embodiment of the present invention constructed as described above, the following advantages can be obtained owing to the fact that boss receiving bores arrayed at an equal pitch are preliminarily formed in the diffuser disc and cylindrical bosses formed at one ends of the diffuser blades are fitted into these bores:
(a) Diffuser blades can be preset precisely at an equal pitch.
(b) Adjustment of the inlet width and outlet width can be achieved easily by merely moving the ends of the diffuser blades remote from the bosses.
(c) A boss formed integrally with a diffuser blade can serve as a reinforcement for the diffuser blade, especially for its thin inlet end portion, and also makes positioning of the diffuser blade simple.
(d) Rigid mounting of a diffuser blade onto a diffuser disc is facilitated, and also there is no fear that the diffuser blade will tilt during brazing.
(e) Exchangeability of diffuser blades is enchanced, and as a result, diffuser blades can be mass-produced at a low cost and can be assembled into products within a short period.
(f) With regard to the set angle of the diffuser blades, it is not always expected that the best result will be obtained by exactly following the design of the angle, and in the event that one fails to obtain the best result, the diffuser device according to the above-described embodiment is especially effective for determining the set angle by seeking the optimum condition by varying the inlet angle, outlet angle, inlet width and outlet width.
It is to be noted that although the size of the boss is restricted in view of the size of the edge area of the diffuser disc, for the purpose of fully realizing the above-described advantages it is preferable to select a diameter of the boss which is not so small. That is, the largest diameter within the range allowed on the diffuser disc should preferably be selected. However, since the disc itself does not any special mechanical strength, with respect to this point there is no need to impose any restriction.
With regard to the mode of bonding the diffuser blades to the diffuser disc, there are the following alternative ways:
(1) When employing an inner diameter D 1 (FIG. 4(b)) of an array of diffuser blades as a reference:
Receiving bores 41 for mounting diffuser blades 9 are formed on the inner diameter portion of a diffuser disc 4, and bosses 9a connected with the diffuser blades 9 by being centered at the radially inner edges of the blades.
(2) When employing an outer diameter D 2 (FIG. 4(b)) of an array of diffuser blades as a reference:
Receiving bores 42 for mounting diffuser blades 9 are formed on the outer diameter portion of a diffuser disc 4, and bosses 9a are connected with the diffuser blades 9 by being centered at the radially outer edges of the blades.
(3) When employing a circle having an arbitrary diameter in an array of diffuser blades as a reference:
Receiving bores for mounting diffuser blades are formed along a circle having an arbitrary diameter on a diffuser disc 4, and bosses 9a are connected with diffuser blades 9 by being centered at arbitrary points on the blades.
In every case, when providing an inlet width a and an outlet width b the diffuser blades are simultaneously adjusted by positioning jigs after transversely moving the diffuser blades about their bosses, and then the diffuser blades are fixed at the adjusted positions and bonded to the diffuser disc by brazing.
As described above, while the position on a diffuser blade where a boss is formed could be any place, for the purpose of adjustment of the mounting angle and enhancement of the reinforcement effect, the position (1) as described above is most preferable.
Summarizing the method for manufacturing a diffuser device according to the above-described embodiment, it consists of the following four steps:
(1) A cylindrical boss is connected with a diffuser blade by being centered at the front or rear edge of the diffuser blade on its inlet end or on its outlet end.
(2) Bores are drilled at an equal pitch in a diffuser disc by employing a blade inlet or a blade outlet as a reference to be used as a reference for mounting diffuser blades.
(3) Diffuser blades are produced by precision casting or precision forging.
(4) Diffuser blades are brazed to a diffuser disc within a thermostate or within an argon atmosphere.
As a result of such structure and/or such method for manufacture of a diffuser device, the following advantages can be obtained:
(1) Where the boss is mounted on the inlet end, the structure can withstand a high frequency vibration induced by an impeller well because the blade and the boss are integrally fixed to the diffuser disc.
(2) The mass-productivity is high, and hence the manufacturing cost can be reduced.
(3) Regardless of respective specifications, a diffuser disc and diffuser blades of a single type can be used in common.
(4) The manufacturing period can be shortened from 3-4 months to 10-15 days.
Now two other preferred embodiments of the present invention, in which adjustment of diffuser blades in a diffuser device is not effected one by one for individual blades but is effected by means of a ganged drive mechanism which enables all the diffuser blades to be rotated simultaneously in the same phase, will be explained in the following with reference to FIGS. 5(a), 5(b), 6(a), 6(b) and 6(c) and FIGS. 7(a), 7(b) and 7(c), respectively.
In FIGS. 5(a), 5(b), 6(a), 6(b) and 6(c), reference numeral 51 designates diffuser blades provided in the gas flow path of a blower, numeral 52 designates a blade sprocket mounted on a rotary shaft of the diffuser blades 51 extending through an inner volute casing 59, numeral 53 designates a roller chain would around a plurality of sprockets 52, and numeral 55 designates a diffuser disc which is interposed between the diffuser blades 51 and the wall surface of the inner volute casing 59 so as to be displaceable in the direction of the rotary shaft of the diffuser blades 51. Reference numeral 54 designates a schematically shown spring-loaded cylinder which either pulls the diffuser disc 55 towards the inner volute casing 59 or pushes it away from the latter. Reference numeral 58 designates an outer volute casing, and reference numeral 60 designates an O-ring provided for the purpose of preventing pressurized gas from escaping through the clearance between the back surface of the diffuser disc 55 and the inner volute casing. Reference numeral 61 designates a shaft for externally driving a chain drive sprocket 52'. It is to be noted that the driving of the diffuser blades 51 could be achieved from the side of the turbine casing 57 on the opposite side of diffuser from the volute casings. Reference numeral 56 designates an impeller of the blower.
Now a description will be given of the operation of the diffuser device constructed in the above-described manner. By actuating the spring-loaded cylinder 54 with compressed air or hydraulic pressure, the diffuser disc 55 is pulled towards the inner volute casing 59 a distance C to form clearances C 1 and C 2 , respectively, ahead of and behind the diffuser blades 51. With the blades in this condition, the drive shaft 61 is driven in rotation to turn drive sprocket 52' to drive roller chain 53 to in turn drive the respective sprockets 52 and thus rotate blades 51, whereby the diffuser blades 51 are adjusted to the desired inlet angle β and to have the desired inlet width a, and thus the desired specifications of the diffuser device can be achieved.
With regard to the change of the blade angle by employing the inner diameter of the blade array as a reference, a description will be given with reference to FIGS. 6(a), 6(b) and 6(c). In these figures, representing the number of the diffuser blades 51 by Zn, the center of the diffuser blade array by O, the centers of rotation for adjustment of the respective diffuser blades by O 1 , O 2 , . . . O n , the central angle of the arc O 1 O 2 by α=360°/Zn=∠O 1 OO 2 , the radius of the sprockets for the respective diffuser blades by R, and the diameter of the circle passing through the centers O 1 , O 2 , . . . O n by D, the amount of movement of every point on the respective sprockets 52 when driving the sprockets for the respective diffuser blades by stretching a roller chain around the respective sprokets is calculated as follows:
(1) Common tangential lines are drawn for two circles having a diameter R and representing the sprockets having two adjacent centers (O n -O 1 , O 1 -O 2 , O 2 -O 3 , etc.), and the common points between the circles O 1 , O 2 , . . . and the common tangential lines are designated by A', A", B', B", . . .
(2) An intersection between a common tangential line for two adjacent circles representing sprockets and a bisector of a central angle α of a regular n-angle polygon determined by the number of blades Zn, is denoted by H. Then, an equation of ∠AOH-(α/2)=∠BOH is fulfilled.
Then, according to the law of trigonometry and the above assemptions (1) and (2), the following relations are derived.
∠AO.sub.1 A"=∠AOH=(α/2)
∠BO.sub.2 B'=∠BOH=(α/2)
hence, we obtain ∠AO 1 A"=∠BO 2 B'
Therefore, when a point A" on a circle having a radius R and its center at O 1 is moved to a point A, a point B on a circle having a radius R and its center at O 2 which circle represents a sprocket coupled via a roller chain to the sprocket represented by the former circle O 1 is moved exactly to a point B'.
The diffuser device according to the above-described embodiment of the present invention provides the following advantages.
(1) The clearances C 1 and C 2 ahead of and behind the diffuser blades can be varied between the period when the diffuser device is operating and the period when the inlet angle β is being varied. Therefore, during operation the diffuser device is operated with minimum clearances near to zero, hence performance is improved and generation of vibrations is limited.
(2) By initially selecting the clearance C to be a maximum value that is allowable in view of performance, during the period of varying the inlet angle β of the diffuser blades driving of the rotary shaft 61 can be achieved with a small torque while maintaining the clearance C 1 and C 2 large.
(3) Since commercially available standard parts can be used, and since the number of parts is reduced, the cost of the diffuser device is lowered.
(4) The manufacturing period can be shortened owing to the use of commercially available parts.
(5) If adjustable pieces are used in the roller chain, fine adjustment of the diffuser blades during assembly can be made.
FIGS. 7(a), 7(b) and 7(c) show still another preferred embodiment of the present invention. Where the number of the diffuser blades 51 is increased to the extent that the adjacent sprockets interfere with each other if the preceding embodiment is employed, this modified embodiment can be conveniently employed, in which the axial positions of the sprockets for the respective diffuser blades are alternately varied, the respective groups of sprockets are coupled with two separate loops of roller chains 53 and 53' for which two separate drive sprockets 52' and 52" are provided so as to drive the respective groups of sprockets through the same angle. The effects and advantages of the diffuser device according to this embodiment are exactly the same as those of the preceding embodiment. | A diffuser device disposed in a passageway between an air outlet of an impeller and a swirl chamber within a casing in a centrifugal compressor, is formed as divided into a diffuser disc capable of being fixed to a casing and a plurality of blades adapted to be arranged along the circumferential direction of the diffuser disc, and the respective diffuser blades have their one ends fitted in fitting bores drilled in the diffuser disc as arrayed along the circumferential direction as many as the diffuser blades so as to be freely rotatable about the axes of the fitting bores, whereby a blade angle is made variable. Also, a method for assembing such a diffuser device in a desired adjusted condition and a ganged drive mechanism for the diffuser blades for bringing the blade angles of the plurality of diffuser blades simultaneously into a desired adjusted condition are disclosed. | 5 |
FIELD OF INVENTION
[0001] This invention relates to methods, which provide access to [F-18]fluoropegylated (aryl/heteroaryl vinyl)-phenyl methyl amine derivatives.
BACKGROUND
[0002] Alzheimer's Disease (AD) is a progressive neurodegenerative disorder marked by loss of memory, cognition, and behavioral stability. AD is defined pathologically by extracellular senile plaques comprised of fibrillar deposits of the beta-amyloid peptide (Aβ) and neurofibrillary tangles comprised of paired helical filaments of hyperphosphorylated tau. The 39-43 amino acids comprising Aβ peptides are derived from the larger amyloid precursor protein (APP). In the amyloidogenic pathway, Aβ peptides are cleaved from APP by the sequential proteolysis by beta- and gamma-secretases. Aβ peptides are released as soluble proteins and are detected at low level in the cerebrospinal fluid (CSF) in normal aging brain. During the progress of AD the Aβ peptides aggregate and form amyloid deposits in the parenchyma and vasculature of the brain, which can be detected post mortem as diffuse and senile plaques and vascular amyloid during histological examination (for a recent review see: Blennow et al. Lancet. 2006 Jul. 29; 368(9533):387-403).
[0003] Alzheimer's disease (AD) is becoming a great health and social economical problem all over the world. There are great efforts to develop techniques and methods for the early detection and effective treatment of the disease. Currently, diagnosis of AD in an academic memory-disorders clinic setting is approximately 85-90% accurate (Petrella J R et al. Radiology. 2003 226:315-36). It is based on the exclusion of a variety of diseases causing similar symptoms and the careful neurological and psychiatric examination, as well as neuropsychological testing.
[0004] Molecular imaging has the potential to detect disease progression or therapeutic effectiveness earlier than most conventional methods in the fields of neurology, oncology and cardiology. Among the several promising molecular imaging technologies, such as optical imaging, MRI, SPECT and PET, PET is of particular interest for drug development because of its high sensitivity and ability to provide quantitative and kinetic data.
[0005] For example positron emitting isotopes include e.g. carbon, iodine, nitrogen and oxygen. These isotopes can replace their non-radioactive counterparts in target compounds to produce PET tracers that have similar biological properties. Among these isotopes F-18 is a preferred labeling isotope due to its half life of 110 min, which permits the preparation of diagnostic tracers and subsequent study of biochemical processes. In addition, its low β+ energy (634 keV) is also advantageous.
[0006] Post-mortem histological examination of the brain is still the only definite diagnosis of Alzheimer's disease. Thus, the in vivo detection of one pathological feature of the disease—the amyloid aggregate deposition in the brain—is thought to have a strong impact on the early detection of AD and differentiating it from other forms of dementia. Additionally, most disease modifying therapies which are in development are aiming at lowering of the amyloid load in the brain. Thus, imaging the amyloid load in the brain may provide an essential tool for patient stratification and treatment monitoring (for a recent review see: Nordberg. Eur J Nucl Med Mol Imaging. 2008 March; 35 Suppl 1:S46-50).
[0007] In addition, amyloid deposits are also known to play a role in amyloidoses, in which amyloid proteins (e.g. tau) are abnormally deposited in different organs and/or tissues, causing disease. For a recent review see Chiti et al. Annu Rev Biochem. 2006; 75:333-66.
[0008] Fluoropegylated (aryl/heteroaryl vinyl)-phenyl methyl amines such as 4-[(E)-2-(4-{2-[2-(2-fluoroethoxy)ethoxy]ethoxy}phenyl)vinyl]-N-methylaniline and 4-[(E)-2-(6-{2-[2-(2-fluoroethoxy)ethoxy]ethoxy}pyridin-3-yl)vinyl]-N-methylaniline have been labeled with F-18 fluoride and are covered by patent applications WO2006066104, WO2007126733 and members of the corresponding patent families.
[0000]
[0009] The usefulness of this radiotracers for the detection of Aβ plaques have been reported in the literature (W. Zhang et al., Nuclear Medicine and Biology 32 (2005) 799-809; C. Rowe et al., Lancet Neurology 7 (2008) 1-7; S. R. Choi et al., The Journal of Nuclear Medicine 50 (2009) 1887-1894).
[0010] To not limit the use of such F-18 labeled diagnostics, processes are needed, that allow a robust and safe manufacturing of the F-18 labeled tracers. Additionally, such processes should provide high yield of the overall synthesis to allow the production of quantities of the diagnostic to supply the radiotracer, despite of the half life of 110 min, to facilities without cyclotron or radiopharmaceutical production facility.
[0011] Syntheses of F-18 labeled fluoropegylated (aryl/heteroaryl vinyl)-phenyl methyl amines have been described before:
4-[(E)-2-(4-{2-[2-(2-[F-18]fluoroethoxy)ethoxy]ethoxy}phenyl)vinyl]-N-methylaniline
[0012]
a) W. Zhang et al., Nuclear Medicine and Biology 32 (2005) 799-809
4 mg precursor 2a (2-[2-(2-{4-[(E)-2-{4-[(tert-butoxycarbonyl)(methyl)amino]-phenyl}vinyl]phenoxy}ethoxy)ethoxy]ethyl methanesulfonate) in 0.2 mL DMSO were reacted with [F-18]fluoride/kryptofix/potassium carbonate complex. The intermediate was deprotected with HCl and neutralized with NaOH. The mixture was extracted with ethyl acetate. The solvent was dried and evaporated. The residue was dissolved in acetonitrile and purified by semi-preparative HPLC (acetonitrile/5 mM dimethylglutarate buffer pH 7 9/1). 20% (decay corrected), 11% (not corrected for decay) 4-[(E)-2-(4-{2-[2-(2-[F-18]fluoroethoxy)ethoxy]ethoxy}phenyl)vinyl]-N-methylaniline were obtained within 90 min. An additional re-Formulation, necessary to obtain a solution suitable for injection into human is not described.
b) WO2006066104
4 mg precursor 2a (2-[2-(2-{4-[(E)-2-{4-[(tert-butoxycarbonyl)(methyl)amino]-phenyl}vinyl]phenoxy}ethoxy)ethoxy]ethyl methanesulfonate) in 0.2 mL DMSO were reacted with [F-18]fluoride/kryptofix/potassium carbonate complex. The intermediate was deprotected with HCl and neutralized with NaOH. The mixture was extracted with ethyl acetate. The solvent was dried and evaporated, the residue was dissolved in acetonitrile and purified by semi-preparative HPLC. 30% (decay corrected), 17% (not corrected for decay) 4-[(E)-2-(4-{2-[2-(2-[F-18]fluoroethoxy)ethoxy]ethoxy}phenyl)vinyl]-N-methylaniline were obtained in 90 min. An additional re-Formulation, necessary to obtain a solution suitable for injection into human is not described. c) C. C. Rowe et al., Lancet Neurology 7 (2008) 129-135 After radiolabeling, acidic hydrolysis and purification by semi-preparative HPLC, 4-[(E)-2-(4-{2-[2-(2-[F-18]fluoroethoxy)ethoxy]ethoxy}phenyl)vinyl]-N-methylaniline was Formulated via solid-phase extraction (SPE).
d) H. Wang et al., Nuclear Medicine and Biology 38 (2011) 121-127
5 mg (9.33 μmol) precursor 2a (2-[2-(2-{4-[(E)-2-{4-[(tert-butoxycarbonyl)(methyl)amino]-phenyl}vinyl]phenoxy}ethoxy)ethoxy]ethyl methanesulfonate) in 0.5 mL DMSO were reacted with [F-18]fluoride/kryptofix/potassium carbonate complex. The intermediate was deprotected with HCl and neutralized with NaOH. The crude product was diluted with acetonitrile/0.1 M ammonium formate (6/4) and purified by semi-preparative HPLC. The product fraction was collected, diluted with water, passed through a C18 cartridge and eluted with ethanol, yielding 17% (not corrected for decay) 4-[(E)-2-(4-{2-[2-(2-[F-18]fluoroethoxy)ethoxy]ethoxy}phenyl)vinyl]-N-methylaniline within 50 min. In the same paper, the conversion of an unprotected mesylate precursor (is described: 5 mg (11.48 μmol) unprotected mesylate precursor (2-{2-[2-(4-{(E)-2-[4-(methylamino)phenyl]vinyl}phenoxy)ethoxy]-ethoxy}ethyl 4-methanesulfonate) in 0.5 mL DMSO were reacted with [F-18]fluoride/kryptofix/potassium carbonate complex. The crude product was diluted with acetonitrile/0.1 M ammonium formate (6/4) and purified by semi-preparative HPLC. The product fraction was collected, diluted with water, passed through a C18 cartridge and eluted with ethanol, yielding 23% (not corrected for decay) 4-[(E)-2-(4-{2-[2-(2-[F-18]fluoroethoxy)ethoxy]ethoxy}phenyl)vinyl]-N-methylaniline within 30 min. A process wherein the radiotracer was purified by SPE (without HPLC) only, was found to afford a product with acceptable radiochemical purity (>95%), however, the chemical purity was too low, e.g. side products derived from the excess of precursor could not be removed.
e) US20100113763
2a (2-[2-(2-{4-[(E)-2-{4-[(tert-butoxycarbonyl)(methyl)amino]phenyl}vinyl]-phenoxy}ethoxy)ethoxy]ethyl methanesulfonate) was reacted with [F-18]fluoride reagent in a mixture of tert-alcohol and acetonitrile. After fluorination, the solvent was evaporated and a mixture of HCl and acetonitrile was added. After deprotection (heating at 100-120° C.), the crude product mixture was purified by HPLC (C18, 60% acetonitrile, 40% 0.1M ammonium formate). An additional re-Formulation, necessary to obtain a solution suitable for injection into human is not described.
4-[(E)-2-(6-{2-[2-(2-(F-18]fluoroethoxy)ethoxy)ethoxy}pyridin-3-yl)vinyl]-N-methylaniline
[0024]
a) S. R. Choi et al., The Journal of Nuclear Medicine 50 (2009) 1887-1894.
1 mg precursor 2b (2-{2-[2-({5-[(E)-2-{4-[(tert-butoxycarbonyl)(methyl)amino]-phenyl}vinyl]pyridin-2-yl}oxy)ethoxy]ethoxy}ethyl 4-methylbenzenesulfonate) in 1 mL DMSO was reacted with [F-18]fluoride/kryptofix/potassium carbonate complex. The intermediate was deprotected with HCl and neutralized with NaOH. DMSO and inorganic components were removed by solid-phase-extraction on SepPak light C18 cartridge (Waters). The crude product was purified by semi-preparative HPLC (55% acetonitrile, 45% 20 mM NH 4 OAc+0.5% w/v sodium ascorbate). The product fraction was diluted with water and passed through a SepPak light C18 cartridge. The radiotracer was eluted with ethanol. The yield for 4-[(E)-2-(6-{2-[2-(2-[F-18]fluoroethoxy)ethoxy]ethoxy}pyridin-3-yl)vinyl]-N-methylaniline was 10-30% (decay corrected).
b) WO2010078370
1.5 mg (2.45 μmol) precursor 2b (2-{2-[2-({5-[(E)-2-{4-[(tert-butoxycarbonyl)(methyl)amino]-phenyl}vinyl]pyridin-2-yl}oxy)ethoxy]ethoxy}ethyl 4-methylbenzenesulfonate) in 2 mL DMSO was reacted with [F-18]fluoride/kryptofix/potassium carbonate complex. The intermediate was deprotected with HCl and diluted with 1% NaOH solution for neutralization. The mixture was loaded onto a reverse phase cartridge. The cartridge was washed with water (containing 5% w/v sodium ascorbate). The crude product was eluted with acetonitrile into a reservoir containing water+5% w/v sodium ascorbate and HPLC solvent. After purification by semi-preparative HPLC, the product fraction was collected into a reservoir containing water+0.5% w/v sodium ascorbate. The solution was passed trough a C18 cartridge, the cartridge was washed with water (containing 0.5% w/v sodium ascorbate and the final product was eluted with ethanol into a vial containing 0.9% sodium chloride solution with 0.5% w/v sodium ascorbate.
c) Y. Liu et al., Nuclear Medicine and Biology 37 (2010) 917-925
1 mg (1.63 μmol) precursor 2b (2-{2-[2-({5-[(E)-2-{4-[(tert-butoxycarbonyl)(methyl)amino]-phenyl}vinyl]pyridin-2-yl}oxy)ethoxy]ethoxy}ethyl 4-methylbenzenesulfonate) in 1 mL DMSO was reacted with [F-18]fluoride/kryptofix/potassium carbonate complex. The intermediate was deprotected with HCl and diluted with 1% NaOH solution. The mixture was loaded onto a Oasis HLB cartridge. The cartridge was washed with water, dried under a flow of argon and the product was eluted with ethanol into a vial containing a saline solution. Although, radiochemical impurities were removed by this procedure, non-radioactive by-products derived from hydrolysis of the excess of precursor, remained in the final product solution. The yield for 4-[(E)-2-(6-{2-[2-(2-[F-18]fluoroethoxy)ethoxy]ethoxy}pyridin-3-yl)vinyl]-N-methylaniline was 34% (non-decay corrected) within 50 min at a radioactive level from 10-100 mCi (370-3700 MBq) of [F-18]fluoride.
d) L. Silva et al., Abstract/Poster EANM 2010
An IBA Synthera platform was adapted for the synthesis of 4-[(E)-2-(6-{2-[2-(2-[F-18]fluoroethoxy)ethoxy]ethoxy}pyridin-3-yl)vinyl]-N-methylaniline. Additionally, a semi-preparative HPLC system and a further Synthera module for re-Formulation was integrated.
e) G. Casale et al. World Journal of Nuclear Medicine, 9 S1 (2010), S-174 (Abstract of 10 th Congress of WFNMB, Cape Town, South Africa, 18-23 Sep. 2010)
The manufacturing of 4-[(E)-2-(6-{2-[2-(2-[F-18]fluoroethoxy)ethoxy]ethoxy}pyridin-3-yl)vinyl]-N-methylaniline have been accomplished by use of an IBA Synthera synthesis module, combined with an HPLC semi preparative purification system and an additional module for Formulation (dilution of HPLC fraction, trapping on a C18 cartridge, washing and elution with ethanol).
[0036] Although, cartridge based purification processes have been investigated, an optimum of product quality regarding radiochemical purity and separation from non-radioactive by-products have been demonstrated and proofed only for HPLC purification. So far, F-18 labeled fluoropegylated (aryl/heteroaryl vinyl)-phenyl methyl amines have been purified by HPLC using solvent systems consisting of acetonitrile and aqueous buffer. Obviously, collected product fractions can not directly used for administration into patient. Acetonitrile and further compounds of the solvent systems that are not tolerated for injection into human have to be removed. This could be accomplished by evaporation or by solid phase extraction (e.g. trapping on C18 solid phase extracting cartridge and elution with ethanol, see FIG. 1 : final solid-phase extraction cartridge C3, elution with ethanol from V8; see also FIG. 7 , final solid-phase extraction cartridge 11, elution with ethanol from one of the vials 9).
[0037] However, especially at higher levels of radioactivity, decomposition of the radiotracer due to radiolysis processes might be an issue. This problem is well known, to prevent radiolysis during the purification of 4-[(E)-2-(6-{2-[2-(2-[F-18]fluoroethoxy)ethoxy]ethoxy}pyridin-3-yl)vinyl]-N-methylaniline sodium ascorbate (as an radical scavenger) was added to the HPLC solvent and to washing solutions (S. R. Choi et al, WO2010078370). However, the concentration of the radiotracer after HPLC by evaporation or by solid-phase extraction is a critical step of the manufacturing. In upscaling experiments, higher radiochemical purities of F-18 labeled fluoropegylated (aryl/heteroaryl vinyl)-phenyl methyl amines can be found after HPLC, before the solid phase extraction compared to the composition after solid phase extraction.
[0038] The general setup of the manufacturing process for F-18 labeled fluoropegylated (aryl/heteroaryl vinyl)-phenyl methyl amines as previously described is illustrated in FIG. 7 . The manufacturing process can be divided into three major parts:
A) Synthesis B) Purification by HPLC C) Formulation
[0042] The manufacturing steps of drying of [F-18]fluoride, radiolabeling of the precursor molecule and deprotection are performed on the part A of the synthesis device ( FIG. 7 ). The crude product mixture is transferred to the second part B for purification by HPLC (on reversed phase silica gel using acetonitrile/buffer eluent). To obtain the radiotracer in a Formulation, suitable for injection into human. The solvent (acetonitrile) present in the product fraction needs to be removed and exchanged by a composition that is appropriate for the manufacturing of a medicament. Typically (and described in the references above), the product fraction is diluted with water (vessel “8”, FIG. 7 , part C) and then passed through a reversed phase cartridge (“11”, FIG. 7 , part C). The cartridge is washed with a aqueous solution from one of the reservoirs 9 ( FIG. 7 , part C) and finally eluted from the cartridge with an ethanolic solution (or ethanol) from another of the reservoirs 9 into the product vial, that optionally comprises further parts and excipients of the final Formulation. It is obvious to those skilled in the art, that the illustration in FIG. 7 is a simplification of process and equipment and that further parts such as valves, vials, tubing ect. can be part of such process or equipment.
[0043] A “GMP compliant” manufacturing process for 4-[(E)-2-(6-{2-[2-(2-[F-18]fluoroethoxy)ethoxy]-ethoxy}pyridin-3-yl)vinyl]-N-methylaniline is disclosed in WO2010078370 and C.-H. Yao et al., Applied Radiation and Isotopes 68 (2010) 2293-2297. To prevent the decomposition of 4-[(E)-2-(6-{2-[2-(2-[F-18]fluoroethoxy)ethoxy]-ethoxy}pyridin-3-yl)vinyl]-N-methylaniline, sodium ascorbate was added to the HPLC solvent (45% acetonitrile, 55% 20 mM ammoniumacetate containing 0.5% (w/v) sodium ascorbate) and the final Formulation (0.5% (w/v) sodium ascorbate). The process afforded up to 18.5 GBq (25.4±7.7%, decay corrected) 4-[(E)-2-(6-{2-[2-(2-[F-18]fluoroethoxy)ethoxy]-ethoxy}pyridin-3-yl)vinyl]-N-methylaniline. The radiochemical purity was 95.3±2.2%.
[0044] Although ascorbate/ascorbic acid is added to solvents involved in the purification, radiochemical purity was only about 95.3±2.2% at product activity levels of up to 18.5 GBq (Yao et al.)—probably due to decomposition by radiolysis.
[0045] At higher product activity levels an even higher variation of radiochemical purity was found for the manufacturing of 4-[(E)-2-(4-{2-[2-(2-[F-18]fluoroethoxy)ethoxy]-ethoxy}phenyl)vinyl]-N-methylaniline (Example 7, FIG. 9 , method A).
[0046] Beside of the variation of radiochemical purity, the re-Formulation during the current process (conversion of the radiotracer from HPLC media into an injectable solution) requires additional process time and demands more complex equipment. For example, the process for the synthesis of 4-[(E)-2-(6-{2-[2-(2-[F-18]fluoroethoxy)ethoxy]ethoxy}pyridin-3-yl)vinyl]-N-methylaniline described by Silva et al. and Casale et al. demands three modules for the overall manufacturing procedure. The Synthesis of the crude product (schematically illustrated in FIG. 7 , Part A) was accomplished on an IBA Synthera module, a semi-preparative HPLC system was used for purification (schematically illustrated in FIG. 7 , Part B) and an additional IBA Synthera synthesis module was used for re-Formulation (schematically illustrated in FIG. 7 , Part C).
[0047] The problem to be solved by the present invention is to provide an improved HPLC purification process for F-18 labeled fluoropegylated (aryl/heteroaryl vinyl)-phenyl methyl amines that provides high chemical and radiochemical purities of the radiotracer, avoiding a concentration of the labeled product after purification to prevent radiolysis, especially at higher levels of radioactivity. Such process should be suitable for the manufacturing of larger quantities (radioactivity) of the radiotracer to allow a distribution to imaging facilities without own radiopharmaceutical production. So far the maximum activity for a F-18 labeled fluoropegylated (aryl/heteroaryl vinyl)-phenyl methyl amine was reported to be 18.5 GBq (Yao et al.). However, even higher yields would be supportive for a widespread use and availability of the radiotracer. A prerequisite of the new manufacturing method should be a high radiochemical purity (e.g. >95%) within a broad range of radioactivity. More precisely, such process should be suitable for the manufacturing of higher activity levels of the radiotracer than previously described (e.g. >20 GBq, or even >50 GBq, or even >100 GBq) with radiochemical purities reliably 95%. As an additional feature such process should be less complex than the processes described before.
[0048] The problems described above were solved by an modified purification procedure. To simplify the overall setup for manufacturing, the solvent composition for HPLC purification was modified. Instead of an acetonitrile/buffer mixture, an ethanol/buffer mixture is used. An advantage of the new HPLC solvent mixture is, that all constituents of the HPLC solvent—in contrast to previously described compositions—are well tolerated as part of a Formulation, thereby suitable for injection into human. Therefore a re-Formulation to remove constituents of the HPLC solvent (as illustrated in FIG. 7 , Part C) is not longer required. This further advantage of the new process—the simplified setup—is schematically illustrated in FIG. 8 . (Obviously, this illustration is a simplification that shows a general setup of the new method described herein.) Following the drawing in FIG. 8 , the product fraction is collected directly (by switching valve “7”) into the product vial (that could contain further parts of the final Formulation). Due to the reduced complexity, the overall manufacturing time by using the new method described herein is shorter, directly contributing to higher non decay corrected yields compared to the previous used process wherein a HPLC purification with additional (time consuming) re-Formulation on a solid-phase cartridge (SPE) is used.
[0049] The major advantage of the new method described herein, is the reliably high radiochemical purity of the F-18 labeled fluoropegylated (aryl/heteroaryl vinyl)-phenyl methyl amines synthesized by the new method. In Example 7 and FIG. 9 the radiochemical purity in dependence of purification method and amount (radioactivity) of radiolabeled product at end of synthesis is demonstrated. The dots/squares (each representing an individual experiment) and the trendlines in FIG. 9 clearly demonstrate that the radiochemical purity obtained after HPLC with re-Formulation by SPE varies significantly ( FIG. 9 , empty squares). Especially at higher radioactivity levels (>20 GBq) the radiochemical purity often is even ≦95%. In contrast, variability of radiochemical purities obtained by the new method of the present invention is much lower and high radiochemical purities of >95% were achieved, even at radioactivity levels of the product of greater than 50 GBq or even greater than 100 GBq ( FIG. 9 , filled dots).
SUMMARY OF THE INVENTION
[0000]
The present invention provides a Method for production of radiolabeled compound of Formula I and suitable salts of an inorganic or organic acid thereof, hydrates, complexes, esters, amides, solvates and prodrugs thereof and a optionally a pharmaceutically acceptable carrier, diluent, adjuvant or excipient.
The method comprises the steps of:
Radiofluorination of compound of Formula II Optionally, cleavage of a protecting group Purification and Formulation of compound of Formula I by HPLC using a solvent system that can be part of an injectable Formulation
[0000]
The Method provided by the present invention is schematically illustrated in FIG. 8 . Radiofluorination of compound of Formula II and optionally, the cleavage of a protecting group are performed on the left-hand part of the equipment ( FIG. 8 , part A). The purification of compound of Formula I is performed in a way, that the product fraction obtained by HPLC ( FIG. 8 , part B) can be directly transferred into the product vial, wherein the product vial optionally contains further pharmaceutically acceptable carriers, diluents, adjuvant or excipients. A further part of process and equipment as illustrated in FIG. 7 (Part C) is not longer required by the Method of the present invention.
The present invention also provides compositions comprising a radiolabeled compound of Formula I or suitable salts of an inorganic or organic acid thereof, hydrates, complexes, esters, amides, solvates and prodrugs thereof and optionally a pharmaceutically acceptable carrier, diluent, adjuvant or excipient.
The present invention also provides a Kit for preparing a radiopharmaceutical preparation by the herein described process, said Kit comprising a sealed vial containing a predetermined quantity of the compound of Formula II.
DESCRIPTION OF THE INVENTION
[0058] In a first aspect the present invention is directed to a Method for producing compound of Formula I
[0000]
[0000] comprising the steps of:
Step 1: Radiolabeling compound of Formula II with a F-18 fluorinating agent, to obtain compound of Formula I, if R═H or to obtain compound of Formula III, if R=PG
[0000]
Step 2: Optionally, if R=PG, cleavage of the protecting group PG to obtain compound of Formula I
Step 3: Purification and Formulation of compound of Formula I
wherein:
n=1-6, preferably 2-4, more preferably 3.
X is selected from the group comprising
a) CH,
b) N.
[0066] In one preferred embodiment, X═CH.
[0067] In another preferred embodiment, X═N.
[0068] R is selected from the group comprising
a) H, b) PG.
[0071] PG is an “Amine-protecting group”.
[0072] In a preferred embodiment, PG is selected from the group comprising:
a) Boc, b) Trityl and c) 4-Methoxytrityl.
[0076] In a more preferred embodiment, R is H.
[0077] In another more preferred embodiment, R is Boc.
[0078] LG is a Leaving group.
[0079] In a preferred embodiment, LG is selected from the group comprising:
a) Halogen and b) Sulfonyloxy.
[0082] Halogen is chloro, bromo or iodo. Preferably, Halogen is bromo or chloro.
[0083] In a preferred embodiment Sulfonyloxy is selected from the group consisting of Methanesulfonyloxy, p-Toluenesulfonyloxy, Trifluormethylsulfonyloxy, 4-Cyanophenylsulfonyloxy, 4-Bromophenylsulfonyloxy, 4-Nitrophenylsulfonyloxy, 2-Nitrophenylsulfonyloxy, 4-Isopropyl-phenylsulfonyloxy, 2,4,6-Triisopropyl-phenylsulfonyloxy, 2,4,6-Trimethylphenylsulfonyloxy, 4-tert-Butyl-phenylsulfonyloxy, 4-Adamantylphenylsulfonyloxy and 4-Methoxyphenylsulfonyloxy.
[0084] In a more preferred embodiment, Sulfonyloxy is selected from the group comprising:
a) Methanesulfonyloxy, b) p-Toluenesulfonyloxy, c) (4-Nitrophenyl)sulfonyloxy, d) (4-Bromophenyl)sulfonyloxy.
[0089] In a even more preferred embodiment LG is Methanesulfonyloxy.
[0090] In another even more preferred embodiment LG is p-Toluenesulfonyloxy.
[0091] A preferred compound of Formula I is:
[0000]
[0000] 4-[(E)-2-(4-{2-[2-(2-[F-18]fluoroethoxy)ethoxy]ethoxy}phenyl)vinyl]-N-methylaniline.
[0092] Another preferred compound of Formula I is:
[0000]
[0000] 4-[(E)-2-(6-{2-[2-(2-[F-18]fluoroethoxy)ethoxy]ethoxy}pyridin-3-yl)vinyl]-N-methylaniline.
[0093] A preferred compound of Formula II is:
[0000]
[0000] 2-[2-(2-{4-[(E)-2-{4-[(tert-butoxycarbonyl)(methyl)amino]phenyl}vinyl]phenoxy}-ethoxy)ethoxy]ethyl methanesulfonate.
[0094] Another preferred compound of Formula II is:
[0000]
[0000] 2-[2-(2-{4-[(E)-2-{4-[(tert-butoxycarbonyl)(methyl)amino]phenyl}vinyl]phenoxy}-ethoxy)ethoxy]ethyl 4-methylbenzenesulfonate
[0095] Another preferred compound of Formula II is:
[0000]
[0000] 2-{2-[2-(4-{(E)-2-[4-(methylamino)phenyl]vinyl}phenoxy)ethoxy]ethoxy}ethyl 4-methylbenzenesulfonate
[0096] Another preferred compound of Formula II is:
[0000]
[0000] 2-{2-[2-(4-{(E)-2-[4-(methylamino)phenyl]vinyl}phenoxy)ethoxy]ethoxy}ethyl 4-methylbenzenesulfonate
[0097] Another preferred compound of Formula II is:
[0000]
[0000] 2-{2-[2-({5-[(E)-2-{4-[(tert-butoxycarbonyl)(methyl)amino]phenyl}vinyl]pyridin-2-yl}oxy)ethoxy]ethoxy}ethyl 4-methylbenzenesulfonate
[0098] Step 1 comprises a straight forward [F-18]fluoro labeling reaction from compounds of Formula II for obtaining compound of Formula I (if R═H) or compound of Formula III (if R=PG).
[0099] The radiolabeling method comprises the step of reacting a compound of Formula II with a F-18 fluorinating agent for obtaining a compound of Formula III or compound of Formula I. In a preferred embodiment, the [F-18]fluoride derivative is 4,7,13,16,21,24-Hexaoxa-1,10-diazabicyclo[8.8.8]-hexacosane K[F-18]F (Kryptofix K[F-18]F), K[F-18]F, H[F-18]F, KH[F-18]F 2 , Cs[F-18]F, Na[F-18]F or tetraalkylammonium salt of [F-18]F (e.g. [F-18]tetrabutylammonium fluoride). More preferably, the fluorination agent is K[F-18]F, H[F-18]F, [F-18]tetrabutylammonium fluoride, Cs[F-18]F or KH[F-18]F 2 , most preferably K[F-18], Cs[F-18]F or [F-18]tetrabutylammonium fluoride.
[0100] An even more preferred F-18 fluorinating agent is kryptofix/potassium[F-18]fluoride, preferably generated from [F-18]fluoride, kryptofix and potassium carbonate.
[0101] The radiofluorination reactions are carried out in acetonitrile, dimethylsulfoxide or dimethylformamide or a mixture thereof. But also other solvents can be used which are well known to someone skilled in the art. Water and/or alcohols can be involved in such a reaction as co-solvent. The radiofluorination reactions are conducted for less than 60 minutes. Preferred reaction times are less than 30 minutes. Further preferred reaction times are less than 15 min. This and other conditions for such radiofluorination are known to experts (Coenen, Fluorine-18 Labeling Methods: Features and Possibilities of Basic Reactions, (2006), in: Schubiger P. A., Friebe M., Lehmann L., (eds), PET-Chemistry—The Driving Force in Molecular Imaging. Springer, Berlin Heidelberg, pp. 15-50).
[0102] In one embodiment, 7.5-75 μmol, preferably 10-50 μmol, more preferably 10-30 μmol and even more preferably 12-25 μmol and even more preferably 13-25 μmol of compound of Formula II are used in Step 1.
[0103] In another embodiment, more than 7.5 μmol, preferably more than 10 μmol, and more preferable more than 12 μmol and even more preferably more than 13 μmol of compound of Formula II are used in Step 1.
[0104] In another embodiment, more than 5 mg, preferably more than 6 mg and more preferably more than 7 mg of compound of Formula II are used in Step 1. In another embodiment 7 mg of compound of Formula II are used in Step 1. In another embodiment 8 mg of compound of Formula II are used in Step 1.
[0105] In one preferred embodiment, the Radiofluorination of compound of Formula II is carried out in acetonitrile or in a mixture of acetonitrile and co-solvents, wherein the percentage of acetonitrile is at least 50%, more preferably at least 70%, even more preferably at least 90%.
[0106] Optionally, if R=PG, Step 2 comprises the deprotection of compound of Formula III to obtain compound of Formula I. Reaction conditions are known or obvious to someone skilled in the art, which are chosen from but not limited to those described in the textbook Greene and Wuts, Protecting groups in Organic Synthesis, third edition, page 494-653, included herewith by reference. Preferred reaction conditions are addition of an acid and stirring at 0° C.-180° C.; addition of an base and heating at 0° C.-180° C.; or a combination thereof.
[0107] Preferably the step 1 and step 2 are performed in the same reaction vessel.
[0108] Step 3 comprises the purification and Formulation of compound of Formula I using a HPLC separation system, wherein, the HPLC solvent eluent (e.g. mixtures of ethanol and aqueous buffers) can be part of the injectable Formulation of compound of Formula I. The collected product fraction can be diluted or mixed with other parts of the Formulation.
[0109] In a preferred embodiment, the HPLC solvent mixture is consisting of ethanol or an aqueous buffer or an ethanol/aqueous buffer mixture, wherein the aqueous buffer is consisting of components or excipient that can be injected into human. Examples for such aqueous buffer are solutions of sodium chloride, sodium phosphate buffer, ascorbic acid, ascorbate buffer or mixtures thereof.
[0110] In a preferred embodiment, the Method for manufacturing of compound of Formula I is carried out by use of a module (review: Krasikowa, Synthesis Modules and Automation in F-18 labeling (2006), in: Schubiger P. A., Friebe M., Lehmann L., (eds), PET-Chemistry—The Driving Force in Molecular Imaging. Springer, Berlin Heidelberg, pp. 289-316) which allows an automated synthesis. More preferably, the Method is carried out by use of an one-pot module. Even more preferable, the Method is carried out on commonly known non-cassette type modules (e.g. Ecker&Ziegler Modular-Lab, GE Tracerlab FX, Raytest SynChrom) and cassette type modules (e.g. GE Tracerlab MX, GE Fastlab, IBA Synthera, Eckert&Ziegler Modular-Lab PharmTracer), optionally, further equipment such as HPLC or dispensing devices are attached to the said modules.
[0111] In a second aspect the present invention is directed to a fully automated and/or remote controlled Method for production of compound of Formula I wherein compounds of Formula I, II and III and Steps 1, 2 and 3 are described above. In a preferred embodiment this method is a fully automated process, compliant with GMP guidelines, that provides a Formulation of Formula I for the use of administration (injection) into human.
[0112] In a third aspect the present invention is directed to a Kit for the production of a pharmaceutical composition of compound of Formula I.
[0113] In one embodiment the Kit comprising a sealed vial containing a predetermined quantity of the compound of Formula II. Preferably, the Kit contains 1.5-75 μmol, preferably 7.5-50 μmol, more preferably 10-50 μmol and even more preferably 12-25 μmol and even more preferably 12-25 μmol and even more preferably 13-25 μmol of compound of Formula II.
[0114] In another embodiment the Kit contains more than 7.5 μmol, preferably more than 10 μmol and more preferably more than 12 μmol and even more preferably more than 13 μmol of compound of Formula II.
[0115] In another embodiment the Kit contains more than 5 mg, preferably more than 6 mg and more preferably more than 7 mg of compound of Formula II.
[0116] In another embodiment the Kit contains 7 mg of compound of Formula II.
[0117] In another embodiment the Kit contains 8 mg of compound of Formula II.
[0118] The kit also contains a solvent or solvent mixture or the components for the solvent(mixture) for HPLC purification, wherein those solvent, solvent mixture or components are appropriate for the direct use for injection into patient.
[0119] Optionally, the Kit contains further components for manufacturing of compound of Formula I, such as solid-phase extraction cartridges, reagent for fluorination (as described above), acetonitrile or acetonitrile and a co-solvent, reagent for cleavage of deprotection group, solvent or solvent mixtures for purification, solvents and excipient for Formulation.
[0120] In one embodiment, the Kit contains a platform (e.g. cassette) for a “cassette-type module” (such as Tracerlab MX or IBA Synthera).
DEFINITIONS
[0121] In the context of the present invention, preferred salts are pharmaceutically suitable salts of the compounds according to the invention. The invention also comprises salts which for their part are not suitable for pharmaceutical applications, but which can be used, for example, for isolating or purifying the compounds according to the invention.
[0122] Pharmaceutically suitable salts of the compounds according to the invention include acid addition salts of mineral acids, carboxylic acids and sulphonic acids, for example salts of hydrochloric acid, hydrobromic acid, sulphuric acid, phosphoric acid, methanesulphonic acid, ethanesulphonic acid, toluenesulphonic acid, benzenesulphonic acid, naphthalene disulphonic acid, acetic acid, trifluoroacetic acid, propionic acid, lactic acid, tartaric acid, malic acid, citric acid, fumaric acid, maleic acid and benzoic acid.
[0123] Pharmaceutically suitable salts of the compounds according to the invention also include salts of customary bases, such as, by way of example and by way of preference, alkali metal salts (for example sodium salts and potassium salts), alkaline earth metal salts (for example calcium salts and magnesium salts) and ammonium salts, derived from ammonia or organic amines having 1 to 16 carbon atoms, such as, by way of example and by way of preference, ethylamine, diethylamine, triethylamine, ethyldiisopropylamine, monoethanolamine, diethanolamine, triethanolamine, dicyclohexylamine, dimethylaminoethanol, procaine, diben-zylamine, N methylmorpholine, arginine, lysine, ethylenediamine and N methylpiperidine.
[0124] The term Halogen or halo refers to Cl, Br, F or I.
[0125] The term “Amine-protecting group” as employed herein by itself or as part of another group is known or obvious to someone skilled in the art, which is chosen from but not limited to a class of protecting groups namely carbamates, amides, imides, N-alkyl amines, N-aryl amines, imines, enamines, boranes, N—P protecting groups, N-sulfenyl, N-sulfonyl and N-silyl, and which is chosen from but not limited to those described in the textbook Greene and Wuts, Protecting groups in Organic Synthesis, third edition, page 494-653, included herewith by reference. The amine-protecting group is preferably Carbobenzyloxy (Cbz), p-Methoxybenzyl carbonyl (Moz or MeOZ), tert-Butyloxycarbonyl (BOC), 9-Fluorenylmethyloxycarbonyl (FMOC), Benzyl (Bn), p-Methoxybenzyl (PMB), 3,4-Dimethoxybenzyl (DMPM), p-methoxyphenyl (PMP) or the protected amino group is a 1,3-dioxo-1,3-dihydro-2H-isoindol-2-yl(phthalimido) or an azido group. The term “Leaving group” as employed herein by itself or as part of another group is known or obvious to someone skilled in the art, and means that an atom or group of atoms is detachable from a chemical substance by a nucleophilic agent. Examples are given e.g. in Synthesis (1982), p. 85-125, table 2 (p. 86; (the last entry of this table 2 needs to be corrected: “n-C 4 F 9 S(O) 2 —O— nonaflat” instead of “n-C 4 H 9 S(O) 2 —O— nonaflat”), Carey and Sundberg, Organische Synthese, (1995), page 279-281, table 5.8; or Netscher, Recent Res. Dev. Org. Chem., 2003, 7, 71-83, scheme 1, 2, 10 and 15 and others). (Coenen, Fluorine-18 Labeling Methods: Features and Possibilities of Basic Reactions, (2006), in: Schubiger P. A., Friebe M., Lehmann L., (eds), PET-Chemistry—The Driving Force in Molecular Imaging. Springer, Berlin Heidelberg, pp. 15-50, explicitly: scheme 4 pp. 25, scheme 5 pp 28, table 4 pp 30, FIG. 7 pp 33).
[0126] The term Sulfonyloxy refers to
[0000] —O—S(O) 2 -Q wherein Q is optionally substituted aryl or optionally substituted alkyl.
[0127] The term “alkyl” as employed herein by itself or as part of another group refers to a C 1 -C 10 straight chain or branched alkyl group such as, for example methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, isopentyl, neopentyl, heptyl, hexyl, decyl or adamantyl. Preferably, alkyl is C 1 -C 6 straight chain or branched alkyl or C 7 -C 10 straight chain or branched alkyl. Lower alkyl is a C 1 -C 6 straight chain or branched alkyl.
[0128] The term “aryl” as employed herein by itself or as part of another group refers to monocyclic or bicyclic aromatic groups containing from 6 to 10 carbons in the ring portion, such as phenyl, naphthyl or tetrahydronaphthyl.
[0129] Whenever the term “substituted” is used, it is meant to indicate that one or more hydrogens on the atom indicated in the expression using “substituted” is/are replaced by one ore multiple moieties from the group comprising halogen, nitro, cyano, trifluoromethyl, alkyl and O-alkyl, provided that the regular valency of the respective atom is not exceeded, and that the substitution results in a chemically stable compound, i. e. a compound that is sufficiently robust to survive isolation to a useful degree of purity from a reaction mixture.
[0130] Unless otherwise specified, when referring to the compounds of Formula the present invention per se as well as to any pharmaceutical composition thereof the present invention includes all of the hydrates, salts, and complexes.
[0131] The term “F-18” means fluorine isotope 18 F. The term“F-19” means fluorine isotope 19F.
Examples
Determination of Radiochemical and Chemical Purity
[0132] Radiochemical and chemical purities of 4-[(E)-2-(4-{2-[2-(2-[F-18]fluoroethoxy)ethoxy]-ethoxy}phenyl)vinyl]-N-methylaniline and 4-[(E)-2-(4-{2-[2-(2-[F-18]fluoroethoxy)ethoxy]-ethoxy}phenyl)vinyl]-N-methylaniline were determined by analytical HPLC (column: Atlantis T3; 150×4.6 mm, 3 μm, Waters; solvent A: 5 mM K 2 HPO 4 pH 2.2; solvent B: acetonitrile; flow: 2 mL/min, gradient: 0:00 min 40% B, 0:00-05:50 min 40-90% B, 05:50-05:60 min 90-40% B, 05:60-09:00 min 40% B).
Retention time of 4-[(E)-2-(4-{2-[2-(2-[F-18]fluoroethoxy)ethoxy]-ethoxy}phenyl)-vinyl]-N-methylaniline: 3.5-3.9 min depending on the HPLC system used for quality control. Due to different equipment (e.g tubing) a difference in retention time is observed between the different HPLC systems. The identity of 4-[(E)-2-(4-{2-[2-(2-[F-18]fluoroethoxy)ethoxy]-ethoxy}phenyl)vinyl]-N-methylaniline was proofed by co-injection with the non-radioactive reference 4-[(E)-2-(4-{2-[2-(2-[F-19]fluoroethoxy)ethoxy]-ethoxy}phenyl)vinyl]-N-methylaniline. Retention time of 4-[(E)-2-(6-{2-[2-(2-[F-18]fluoroethoxy)ethoxy]-ethoxy}pyridin-3-yl)vinyl]-N-methylaniline: 3.47 min. The identity of 4-[(E)-2-(6-{2-[2-(2-[F-18]fluoroethoxy)ethoxy]-ethoxy}pyridin-3-yl)vinyl]-N-methylaniline was proofed by co-elution with the non-radioactive reference -[(E)-2-(6-{2-[2-(2-[F-19]fluoroethoxy)ethoxy]-ethoxy}pyridin-3-yl)vinyl]-N-methylaniline.
Example 1
Synthesis of 4-[(E)-2-(4-{2-[2-(2-[F-18]fluoroethoxy)ethoxy]-ethoxy}phenyl)vinyl]-N-methylaniline radiosynthesis on Eckert&Ziegler modular lab
[0135]
[0136] The synthesis of 4-[(E)-2-(4-{2-[2-(2-[F-18])fluoroethoxy)ethoxy]-ethoxy}phenyl)vinyl]-N-methylaniline have been performed on a Eckert&Ziegler modular lab synthesizer. [F-18]Fluoride (60362 MBq) was trapped on a QMA cartridge. The activity was eluted with potassium mesylate/kryptofix/n-Bu 4 NHCO 3 /methanol mixture into the reactor. The solvent was removed while heating under gentle nitrogen stream and vacuum. Drying was repeated after addition of acetonitrile. A solution of 4 mg 2a in 1 mL tert-amylalcohol/acetonitrile (9:1) was added to the dried residue and the mixture was heated for 20 min at 120° C. During heating, the exhaust of the reactor was opened to allow the evaporation of the solvent. A mixture of 2.2 mL 1.5M HCl, 1.1 mL acetonitrile and 30 mg sodium ascorbate was added and the reactor was heated at 100° C. for 10 min. The crude product was neutralized (1.5 mL 2M NaOH+0.3 mL buffer) and transferred to a semi-preparative HPLC column (Synergy Hydro-RP, 250×10 mm, Phenomenex). A mixture of 60% ethanol and 40% ascorbate buffer (pH 7.0) was flushed through the column with 3 mL/min. The product fraction at ≈18 min ( FIG. 2 ) was directly collected into the product vial containing 8.5 mL Formulation basis (phosphate buffer, ascorbic acid, PEG400). Analytical HPLC of the final product ( FIG. 3 ) showed excellent radiochemical and chemical purity. Only cold 4-[(E)-2-(4-{2-[2-(2-[F-18]fluoroethoxy)ethoxy]-ethoxy}phenyl)vinyl]-N-methylaniline have been detected in the UV chromatogram ( FIG. 3 , bottom), all non-radioactive impurities have been separated. The radiochemical purity was determined to be 99.6%.
Example 2
Synthesis of 4-[(E)-2-(4-{2-[2-(2-[F-18]fluoroethoxy)ethoxy]-ethoxy}phenyl)vinyl]-N-methylaniline radiosynthesis on Tracerlab FX N
[0137] A Tracerlab FX N synthesizer have been adopted to the “direct cut HPLC approach” ( FIG. 4 ).
[0138] [F-18]Fluoride (3700 MBq) was trapped on a QMA cartridge. The activity was eluted with potassium carbonate/kryptofix/acetonitrile/water mixture into the reactor. The solvent was removed while heating under gentle nitrogen stream and vacuum. Drying was repeated after addition of acetonitrile. A solution of 7 mg 2a in 1 mL acetonitrile was added to the dried residue and the mixture was heated for 8 min at 120° C. After cooling to 60° C., a mixture of 0.5 mL 2M HCl, and 0.5 mL acetonitrile was added and the reactor was heated at 110° C. for 4 min. The crude product was neutralized (1 mL 1M NaOH+2 mL buffer) and transferred to a semi-preparative HPLC column (Synergy Hydro-RP, 250×10 mm, Phenomenex). A mixture of 60% ethanol and 40% ascorbate buffer (pH 7.0) was flushed through the column with 3 mL/min. The product fraction at ≠16 min ( FIG. 2 ) was directly collected into the product vial containing 8.5 Formulation basis (phosphate buffer, ascorbic acid, PEG400). Radiochemical purity was determined to be >99%.
Example 3
Synthesis of 4-[(E)-2-(4-{2-[2-(2-[F-18]fluoroethoxy)ethoxy]-ethoxy}phenyl)vinyl]-N-methylaniline radiosynthesis on Tracerlab MX and Eckert&Ziegler Purification unit
[0139] A Kit have been assembled for the synthesis of 4-[(E)-2-(4-{2-[2-(2-[F-18]fluoroethoxy)ethoxy]-ethoxy}phenyl)vinyl]-N-methylaniline (Table 1).
[0000]
TABLE 1
Composition of Kit for manufacturing of 4-[(E)-2-(4-{2-[2-(2-[F-
18]fluoroethoxy)ethoxy]-ethoxy}phenyl)vinyl]-N-methylaniline on
tracerlab MX and Eckert&Ziegler Purification unit
Eluent vial
22 mg kryptofix. 7 mg potassium carbonate in 300
μL water + 300 μL acetonitrile
Blue capped vial
8 mL acetonitrile
Red capped vial
8 mg precursor 2a
Green capped vial
2 mL 1.5M HCl + 30 mg sodium ascorbate
2 mL syringe
1.5 mL 2M NaOH + 0.3 mL phosphate buffer
Water bag
Water
Product line to
Tube with two luer lock fittings
Eckert&Ziegler
purification unit
Anion exchange cartridge
QMA light, Waters (pre-conditioned)
Disposable 3-way valve
With tubing and needle to product vial, incl. sterile
filters
Product vial
20 mL vial
Formulation basis
8.5 mL (PEG 400, Na 2 HPO 4 •H 2 O,
ascorbic acid in water)
HPLC solvent
ethanol
water
sodium ascorbate
ascorbic acid
HPLC flow rate
3 mL/min
[0140] The design of the Tracerlab MX cassette has been adopted ( FIG. 5 ). [F-18]Fluoride was trapped on the QMA cartridge. The activity was eluted with potassium carbonate/kryptofix/acetonitrile/water mixture (from “eluent vial”) into the reactor. The solvent was removed while heating under gentle nitrogen stream and vacuum. Drying was repeated after addition of acetonitrile. A solution of 8 mg 2a in 1.8 mL acetonitrile (acetonitrile from “blue capped vial” was added to solid 2a in the “red capped vial” during the sequence) was added to the dried residue and the mixture was heated for 10 min at 120° C. 1.5M HCl (from “green capped vial”) was added and the reactor was heated at 110° C. for 5 min. The crude product was neutralized (1 mL 1M NaOH+0.3 mL buffer, from “2 mL syringe”) and transferred to the injection valve of the Eckert&Ziegler HPLC ( FIG. 6 ) by the left syringe pump of the MX module. The crude product was purified on a Synergy Hydro-RP, 250×10 mm, Phenomenex HPLC column using a mixture of 60% ethanol and 40% ascorbate buffer (pH 7.0). The product fraction at ≈17.5 min ( FIG. 2 ) was directly collected into the product vial containing 8.5 Formulation basis (phosphate buffer, ascorbic acid, PEG400).
Example 4
Synthesis of 4-[(E)-2-(4-{2-[2-(2-[F-18]fluoroethoxy)ethoxy]-ethoxy}phenyl)vinyl]-N-methylaniline radiosynthesis on Eckert&Ziegler modular lab
[0141] The synthesis has been performed on Eckert & Ziegler ModularLab synthesizer using acetonitrile as solvent for fluorination. The setup of the synthesizer and the results are summarized in Table 2.
[0142] [F-18]Fluoride was trapped on a QMA cartridge (C1). The activity was eluted with a kryptofix mixture (from “V1”) into the reactor. The solvent was removed while heating under gentle nitrogen stream and vacuum. Drying was repeated after addition of 100 μL acetonitrile (from “V2”). The solution of precursor 2a (from “V3”) was added to the dried residue and the mixture was heated for 10 min at 120° C. After cooling to 40° C., 2 mL 1.5M HCl (from “V4”) was added and solution was heated for 5 min at 110° C.
[0143] The crude product mixture was diluted with 1.2 mL 2M NaOH and 0.8 mL ammonium formate (1 M) from vial “V5” and then transferred to the HPLC vial (“Mix-Vial”) containing previously 1 mL acetonitrile and 0.5 mL ethanol.
[0144] The mixture was transferred to the 10 mL sample injection loop of the semi-preparative HPLC using a nitrogen overpressure in the HPLC vial (“Mix-Vial”) and via a liquid sensor which controlled the end of the loading. The mixture is loaded to the semi-preparative HPLC column (Synergi Hydro-RP, 250×10 mm, Phenomenex). A mixture of 60% ethanol and 40% ascorbate buffer was flushed through the column with 6 mL/min. The product fraction at ≈7 min was collected directly into the product vial containing 15 mL Formulation basis (consisting of phosphate buffer, PEG400 and ascorbic acid). Analytical HPLC of the final product showed excellent radiochemical and chemical purity. No impurity higher than 0.3 μg/mL was quantified.
[0000]
TABLE 2
Vial V1
22 mg kryptofix
7 mg potassium carbonate
300 μL acetonitrile
300 μL water
Vial V2
100 μL acetonitrile
Vial V3
8 mg precursor 2a in 1.8 mL acetonitrile
Vial V4
2 mL HCl 1.5M
Vial V5
1.2 mL NaOH 2.0M
800 μL ammonium formate 1M
Cartridge C1
QMA light (waters) conditioned with potassium
carbonate 0.5M
Mix-Vial
1 mL acetonitrile
500 μL ethanol
HPLC column
Synergi Hydro-RP, 250*10 mm, 10 μm 80Å, Phenomenex
HPLC solvent
60% ethanol, 40% ascorbate buffer (5 g/l sodium ascorbate
and 50 mg/l ascorbic acid)
HPLC flow
6 mL/min
Start activity of
46.0 GBq
[F-18]fluoride
Product activity
19.4 GBq
Product radio-
99%
purity (RCP)
Radiochemical
42% (not corrected for decay)
yield
Example 5
Synthesis of 4-[(E)-2-(4-{2-[2-(2-[F-18]fluoroethoxy)ethoxy]-ethoxy}phenyl)vinyl]-N-methylaniline radiosynthesis on tracerlab MX and Eckert&Ziegler Purification Unit
[0145] The synthesis has been performed on GE TracerLab MX synthesizer, purification of 4 has been performed on Eckert & Ziegler Purification Unit. The filling of the injection loop of the HPLC was controlled using the syringe of the MX module. The setup of both automates and the results are summarized in the Table below. [F-18]Fluoride was trapped on a QMA cartridge (C1). The activity was eluted with a kryptofix mixture (from “V1”) into the reactor. The solvent was removed while heating under gentle nitrogen stream and vacuum. Drying was repeated after addition of acetonitrile (from “V2”). The solution of precursor 2a (from “V3”) was added to the dried residue and the mixture was heated for 10 min at 120° C. After cooling to 40° C., 2 mL 1.5M HCl (from “V4”) was added and solution was heated for 5 min at 110° C.
[0146] The crude product mixture was diluted with 1.2 mL 2M NaOH and 0.8 mL ammonium formate (1 M) from syringe “S1” and then transferred to the HPLC vial (“Mix-Vial”) in which 1 mL acetonitrile (from “V2”) and 0.5 mL ethanol (from “V5”) are added separately.
[0147] The average 6-7 mL mixture was transferred to a 30 mL syringe which then pushed the totality of the volume into the 10 mL sample injection loop of the semi-preparative HPLC. The mixture is loaded to the semi-preparative HPLC column (Synergi Hydro-RP, 250×10 mm, Phenomenex). A mixture of 60% ethanol and 40% ascorbate buffer was flushed through the column with 6 mL/min. The product fraction at ≈9 min was collected for 50 sec directly into the product vial containing 15 mL Formulation basis (consisting of phosphate buffer, PEG400 and ascorbic acid). Analytical HPLC of the final product showed excellent radiochemical and chemical purity. No impurity higher than 0.5 μg/mL was quantified.
[0000]
TABLE 3
Vial V-1
22 mg kryptofix
7 mg potassium carbonate
300 μL acetonitrile
300 μL water
Vial V2
8 mL acetonitrile
Vial V3
8 mg precursor in 1.8 mL acetonitrile
Vial V4
2 mL HCl 1.5M
Vial V5
8 mL ethanol
Syringe S1
1.2 mL NaOH 2.0M
800 μL ammonium formate 1M
Cartridge C1
QMA light (waters) conditioned with potassium
carbonate 0.5M
HPLC column
Synergi Hydro-RP, 250* × 10 mm, 10 μm 80Å, Phenomenex
HPLC solvent
60% ethanol, 40% ascorbate buffer (5g/l sodium ascorbate
and 50 mg/l ascorbic acid)
HPLC flow
6 mL/min
Start activity of
36.9 GBq
[F-18]fluoride
Product activity
14.2 GBq
Product radio-
100%
purity (RCP)
Radiochemical
38% (not corrected for decay)
yield
[0148] Example 6 Synthesis of 4-[(E)-2-(4-{2-[2-(2-[F-18]fluoroethoxy)ethoxy]-ethoxy}phenyl)vinyl]-N-methylaniline radiosynthesis on tracerlab MX and Eckert&Ziegler Purification Unit
[0149] The synthesis has been performed on GE TracerLab MX synthesizer, purification of 4 has been performed on Eckert & Ziegler Purification Unit. The filling of the injection loop of the HPLC was controlled by a fluid detector of the Eckert&Ziegler Purification unit. The setup of both automates and the results are summarized in the Table below. [F-18]Fluoride was trapped on a QMA cartridge (C1). The activity was eluted with a kryptofix mixture (from “V1”) into the reactor. The solvent was removed while heating under gentle nitrogen stream and vacuum. Drying was repeated after addition of acetonitrile (from “V2”). The solution of precursor (from “V3”) was added to the dried residue and the mixture was heated for 10 min at 120° C. After cooling to 40° C., 2 mL 1.5M HCl (from “V4”) was added and solution was heated for 5 min at 110° C.
[0150] The crude product mixture was diluted with 1.2 mL 2M NaOH and 0.8 mL ammonium formate (1 M) from syringe “S1”. 1 mL acetonitrile (from “V2”) and 0.5 mL ethanol (from “V5”) are added separately to the mixture and then transferred to the right syringe of the GE TracerLab MX automate.
[0151] The mixture was transferred to the 10 mL sample injection loop of the semi-preparative HPLC using the right syringe of the GE TracerLab MX automate via a liquid sensor which controlled the end of the loading. The mixture was loaded to the semi-preparative HPLC column (Synergi Hydro-RP, 250×10 mm, Phenomenex). A mixture of 60% ethanol and 40% ascorbate buffer was flushed through the column with 6 mL/min. The product fraction at ≈9 min was collected directly during 50 sec into the product vial containing 15 mL Formulation basis (consisting of phosphate buffer, PEG400 and ascorbic acid). Analytical HPLC of the final product showed excellent radiochemical and chemical purity. No impurity higher than 0.7 μg/mL was quantified.
[0000]
TABLE 4
Vial V1
22 mg kryptofix
7 mg potassium carbonate
300 μL acetonitrile
300 μL water
Vial V2
8 mL acetonitrile
Vial V3
8 mg precursor in 1.8 mL acetonitrile
Vial V4
2 mL HCl 1.5M
Vial V5
8 mL ethanol
Syringe S1
1.2 mL NaOH 2.0M
800 μL ammonium formate 1M
Cartridge C1
QMA light (waters) conditioned with potassium
carbonate 0.5M
HPLC column
Synergi Hydro-RP, 250* × 10 mm, 10 μm 80Å, Phenomenex
HPLC solvent
60% ethanol, 40% ascorbate buffer (5 g/l sodium ascorbate
and 50 mg/l ascorbic acid)
HPLC flow
6 mL/min
Start activity of
62.2 GBq
[F-18]fluoride
Product activity
24.8 GBq
Product radio-
100%
purity (RCP)
Radiochemical
40% (not corrected for decay)
yield
Example 7
Influence of Purification Method on Radiochemical Purity
[0152] A series of 4-[(E)-2-(4-{2-[2-(2-[F-18]fluoroethoxy)ethoxy]-ethoxy}phenyl)vinyl]-N-methylaniline syntheses was performed on two different synthesizers (Eckert & Ziegler modular lab and GE tracerlab MX) as generally described in the examples 1, 3-6. The radiolabelings have been performed using 4-10 mg precursor 2a in acetonitrile as well as in tert-amylalcohol/acetonitrile mixture at 100-120° C. for 10-20 min. (in case of radiolabelings in tert-amylalcohol the solvent was evaporated prior deprotection). The N-Boc protecting group was removed by heating with HCl (1.5M-2M).
[0153] Crude product mixtures were individually purified by one of the two methods A) or B).
Method A):
[0154] The crude product mixture obtained after deprotection is neutralized with a mixture of 2M NaOH and 0.1M ammonium formate and injected onto a semipreparative HPLC (e.g. column: Gemini C18, 10×250 mm, 5 μm, Phenomenex; solvent: 70% acetonitrile, 30% ammonium formate buffer 0.1M with 5 mg/mL sodium ascorbate, flow rate 3 mL/min). The product fraction is collected into a flask containing approx. 160 mL water with 10 mg/mL sodium ascorbate. The mixture is passed through a C18 cartridge (tC18 SepPak environmental, Waters). The cartridge is washed with approx. 8-10 mL 20% EtOH in water (containing 10 mg/mL sodium ascorbate). Finally, the product is eluted with 1.5 to 3 mL ethanol into a vial containing 8.5 to 17 mL “Formulation basis” (comprising PEG400, phosphate buffer and ascorbic acid).
Method B):
[0155] The crude product mixture obtained after deprotection is neutralized with a mixture of 2M NaOH and 0.1M ammonium formate and injected onto a semipreparative HPLC (column: e.g.: Gemini C18, 10×250 mm, 5 μm, Phenomenex or Synergi Hydro-RP, 250×10 mm, 10 μm 80 Å, Phenomenex or Synergi Hydro-RP, 250×10 mm, 4 μm 80 Å, Phenomenex; solvent: 60-70% ethanol, 40-30% ascorbate buffer ≈5 mg/mL ascorbate; flow 3 mL/min or 4 mL/min or 6 mL/min). The product fraction is directly collected into a vial containing “Formulation basis” (comprising PEG400, phosphate buffer and ascorbic acid) to provide 10-24 mL of the final Formulation. The peak-cutting time was adjusted in the software to obtain a Formulation comprising 15% EtOH.
[0156] Every empty square (each one result for a synthesis comprising a purification by method A, 110 experiments) and every filled dot (each one result for a synthesis comprising a purification by method B, 105 experiments) in FIG. 9 represents an individual experiment for the manufacturing of 4-[(E)-2-(4-{2-[2-(2-[F-18]fluoroethoxy)ethoxy]-ethoxy}phenyl)vinyl]-N-methylaniline. The tendency of radiochemical purity in correlation with radioactivity of the final product is illustrated by linear trendlines.
[0157] The radiochemical purity obtained after HPLC with re-Formulation by SPE (method A) varies significantly ( FIG. 9 , empty squares). Especially at higher radioactive levels (>20 GBq) the radiochemical purity often is even ≦95%.
[0158] In contrast, variability is much lower for method B). Consistently high radiochemical purities of >95% were achieved at activity levels of the product of greater than 50 GBq, and even greater than 100 GBq ( FIG. 9 , filled dots).
Example 8
Synthesis of 4-[(E)-2-(6-{2-[2-(2-[F-18]fluoroethoxy)ethoxy]-ethoxy}pyridin-3-yl)vinyl]-N-methylaniline on Tracerlab FX N
[0159]
[0160] A Tracerlab FX N synthesizer has been adopted to the “direct cut HPLC approach” ( FIG. 4 ).
[0161] [F-18]Fluoride (10 GBq) was trapped on a QMA cartridge. The activity was eluted with potassium carbonate/kryptofix/acetonitrile/water mixture into the reactor. The solvent was removed while heating under gentle nitrogen stream and vacuum. Drying was repeated after addition of acetonitrile. A solution of 8 mg 2b in 1.5 mL acetonitrile was added to the dried residue and the mixture was heated for 10 min at 120° C. After cooling to 60° C., 1 mL 1.5M HCl was added and the reactor was heated at 110° C. for 5 min. The crude product was neutralized (1 mL 1M NaOH/ammonium formate), diluted (with 0.5 mL EtOH and 1.5 mL MeCN) and transferred to a semi-preparative HPLC column (Synergy Hydro-RP, 250×10 mm, Phenomenex). A mixture of 60% ethanol and 40% ascorbate buffer (5 g/l sodium ascorbate and 50 mg/l ascorbic acid, pH 7.0) was flushed through the column with 3 mL/min. The product fraction at ≈10 min (see FIG. 10 ) was directly collected for 100 sec and mixed with 15 mL Formulation basis (phosphate buffer, ascorbic acid, PEG400).
[0162] 4.2 GBq (42% not corrected for decay) were obtained in 61 min overall synthesis time. Radiochemical purity (determined by HPLC, t R =3.42 min) was determined to be >99%.
Example 9
Synthesis of 4-[(E)-2-(4-{2-[2-(2-[F-18]fluoroethoxy)ethoxy]-ethoxy}phenyl)vinyl]-N-methylaniline on Tracerlab FX N
[0163]
[0164] A Tracerlab FX N synthesizer have been adopted to the “direct cut HPLC approach” ( FIG. 4 ).
[0165] [F-18]Fluoride (6.85 GBq) was trapped on a QMA cartridge. The activity was eluted with potassium carbonate/kryptofix/acetonitrile/water mixture into the reactor. The solvent was removed while heating under gentle nitrogen stream and vacuum. Drying was repeated after addition of acetonitrile. A solution of 8 mg 2c in 1.5 mL acetonitrile was added to the dried residue and the mixture was heated for 10 min at 120° C. After cooling to 60° C., the crude product was diluted with 4 mL HPLC eluent and transferred to a semi-preparative HPLC column (Synergy Hydro-RP, 250×10 mm, Phenomenex). A mixture of 60% ethanol and 40% ascorbate buffer (5 g/l sodium ascorbate and 50 mg/l ascorbic acid, pH 7.0) was flushed through the column with 3 mL/min. The product fraction at ≈12 min was directly collected for 100 sec and mixed with 15 mL Formulation basis (phosphate buffer, ascorbic acid, PEG400).
[0166] 2.54 GBq (37% not corrected for decay) were obtained in 53 min overall synthesis time. Radiochemical purity (determined by HPLC, t R =3.78 min) was determined to be >99%.
DESCRIPTION OF THE FIGURES
[0167] FIG. 1 Setup of Tracerlab FX N for purification with re-Formulation (adopted from tracerlab software)
[0168] FIG. 2 Chromatogramm of purification using Synergy column on Eckert&Ziegler modular lab (Radioactivity channel)
[0169] FIG. 3 Analytical HPLC of radiolabeled product (top radioactivity channel, bottom UV channel)
[0170] FIG. 4 Setup of Tracerlab FX N for purification without re-Formulation (adopted from tracerlab software)
[0171] FIG. 5 Setup of Tracerlab MX (adopted from Coincidence FDG software)
[0172] FIG. 6 Setup of Eckert&Ziegler purification unit (adopted from Modual-Lab software)
[0173] FIG. 7 Schematic illustration of process and equipment for manufacturing of F-18 labeled fluoropegylated (aryl/heteroaryl vinyl)-phenyl methyl amines comprising three parts: A) Synthesis, B) HPLC, C) Formulation; including (1) vials for reagents and solvents, (2) a reaction vessel, (3) target line for F-18, optionally gas lines, vacuum ect., (4) optionally fluid detector or filter ect., (5) injection valve, (6) HPLC column, (7) valve for peak cutting, (W) waste line(s), (8) vessel for collection/dilution of HPLC fraction, (9) solvent vials for washing and elution, (10) valve, (11) cartridge, e.g. C18 cartridge for trapping of the product, (12) valve.
[0174] FIG. 8 Schematic illustration of process and equipment for manufacturing of F-18 labeled fluoropegylated (aryl/heteroaryl vinyl)-phenyl methyl amines comprising two parts: A) Synthesis, B) HPLC; including (1) vials for reagents and solvents, (2) a reaction vessel, (3) target line for F-18, optionally gas lines, vacuum ect., (4) optionally fluid detector or filter ect., (5) injection valve, (6) HPLC column, (7) valve for peak cutting.
[0175] FIG. 9 Influence of purification method on radiochemical purity
[0176] FIG. 10 Chromatogramm of purification of 4-[(E)-2-(6-{2-[2-(2-[F-18]fluoro-ethoxy)ethoxy]ethoxy}pyridin-3-yl)vinyl]-N-methylaniline on Eckert&Ziegler modular lab (Radioactivity channel) | This invention relates to methods, which provide access to [F-18]fluoropegylated (aryl/heteroaryl vinyl)-phenyl methyl amine derivatives. | 2 |
BACKGROUND OF THE INVENTION
1. Field Of The Invention
The present invention relates to the field of electrical connectors for coaxial cables and, more particularly, to the class of zero insertion force (ZIF) connectors having receptacles constructed of wire formed in the shape of a single- or double-helix.
In ZIF connectors, pressure between a mating pair of contacts in a male connector part and female receptacle is temporarily withheld during coupling or decoupling, typically by causing a temporary enlargement of the effective inside diameter of the female receptacle so as to disengage the male contact during insertion or removal.
The splicing of two coaxial cable ends requires first removing the insulation from each end, mounting a male fitting on each end, and then screwing the fittings onto a double-ended adapter having opposing female threads in each end. Typically, special tooling is required to apply the fittings, which if improperly applied can result in unreliable performance. The splicing process as presently practiced requires multiple successive operations which are time consuming to execute and require extensive practice to perfect.
There is thus an ongoing and unfulfilled need to easily and efficiently connect and disconnect coaxial cables to each other, whether in a stand-alone device, mounted in a panel, or mounted within electronic equipment.
2. Description Of The Related Art
The use in electrical connectors of single-helix spring coils as variable diameter clamping elements is known in the art. U.S. Pat. No. 4,082,399 to Barkhuff is directed to a ZIF connector wherein a plurality of resilient helical contact members each receive a pin of a multi-pin module.
U.S. Pat. No. 3,518,614 to Nyberg is directed to a receptacle having a plurality of coiled springs attached to and positioned between a pair of rotatable plates. When the plates are rotated with respect to each other in one direction the inner diameters of the coiled springs are simultaneously increased; when rotated in the other direction the diameters are decreased.
U.S. Pat. No. 4,874,909 to Velke, Sr. et al., is directed to a connector for butting the ends of two single-conductor cables within a helically coiled grip element.
U.S. Pat. No. 3,440,333 to Blomstrand is directed to a connector including a helically coiled spring to grip the ends of a plurality of parallel wires without resort to soldering or welding.
U.S. Pat. No. 3,295,872 to Kragle uses a single helical spring to provide a mechanical grip on a coaxial cable. The spring does not contact the outer-conductor of the coaxial cable and thus is not involved in electrical connection.
U.S. Pat. No. 2,427,001 to Hubbel et al., is directed to a panel-mounted receptacle including a coiled spring within a longitudinal chamber which receives and grips a male pin or plug. This is not a ZIF device as there is no provision to enlarge or contract the spring opening.
U.S. Pat. No. 4,192,567 to Gomolka is directed to a ZIF electrical connector including a male connector part having a plurality of prongs, and a female connector part including a corresponding plurality of receptacles, each containing a coiled spring. The connector includes means to expand or contract the coiled spring receptacles.
U.S. Pat. No. 5,042,146 to the present inventor discloses forming interconnecting hookup wire into a double-helix configuration. The double-helix serves as a receptacle for receiving component leads or other hookup wire ends for soldering, and also provides an integrally connected point-to-point hookup wiring alternative to printed circuit traces.
None of the above-cited references provide for zero-insertion force connection simultaneously to an inner conductor and an outer-conductor as exist in a coaxial cable.
U.S. Pat. No. 5,154,626 ("626") issued to the present inventor on Oct. 13, 1992, entitled "Double-Helix Zero Insertion Force Connector System", discloses a method to use an interleaved double-helix receptacle as a ZIF connector and is incorporated herein in its entirety by this reference. A double-helix, formed from a length of bared or uninsulated wire, includes a bridging loop which connects the two helix halves. Applying a rotational torque to the loop causes the receptacle opening to expand or contract.
The '626 patent primarily is directed to an embodiment where the male connector part includes a cylindrical contact pin which is engaged by a double-helix coil disposed within a female receptacle. A second embodiment of the '626 patent discloses a double-helix receptacle for connecting the bared center-conductor of two coaxial cables, but does not disclose a ZIF connector enabling coaxial cable ends to be easily and reliably connected so as to achieve strong mechanical connection as well as electrical connection between the two center-conductors and two outer-conductors.
OBJECTS OF THE INVENTION
Accordingly, it is a primary object of the present invention to provide an improved connector or coupler over current techniques to join the ends of two coaxial cables, which securely connects the cable ends mechanically while providing reliable electrical connectivity between the two center-conductors and the two coaxial outer-conductors.
Another object of the invention is to provide a connector or coupler enabling two coaxial cable ends to be connected and disconnected in a zero insertion force manner.
A further object of the invention is to accomplish zero insertion force connection or disconnection of two coaxial cable ends without applying a large rotational torque to the connector or coupler.
Yet another object of the invention is to provide a connector or coupler which when used to connect two coaxial cables results in a consistent and uniform characteristic impedance, without injecting any disruptions or noise.
A further object of the invention is to provide a connector or coupler which is of rugged construction.
Another object of the invention is to provide a connector or coupler that is simple, reliable, and easy to use.
One more object of the invention is to provide a connector or coupler that is inexpensive to manufacture.
Other objects of the invention will become evident when the following description is considered with the accompanying drawings.
SUMMARY OF THE INVENTION
The above and other objects are met by the present invention, a coupler having two opposing receptacles each including an inner, relatively small diameter single- or interleaved multiple-helix which closely receives the center-conductor of a coaxial cable, and an outer, larger diameter single- or interleaved multiple-helix which closely receives the outer-conductor. The interior cross-sectional areas of each receptacle helix pair may be contracted to contact and grip the center-conductor and outer-conductor and may be enlarged to allow easy insertion or removal of a coaxial cable. A large surface area around the circumference of a mating male coaxial cable is contacted, providing high electrical conductivity and strong mechanical gripping. By fabricating the helixes from a resilient material, the helix receptacles are self-constrictive. By providing limited slippage of a mechanism controlling the cross-sectional area of either an inner or outer helix receptacle, one helix can firmly engage its male contact before the other helix engages its contact.
A first preferred embodiment includes opposed first and second receptacle sub-assemblies disposed, respectively, within first and second cylindrical sleeves, and separated by a cylindrical insulating base. Each receptacle sub-assembly includes an inner double-helix receptacle formed from interleaved, coiled first and second bare wires and having an alterable inner circular cross-sectional area which can be enlarged and then contracted so as to easily receive and then provide constriction around a coaxial cable center-conductor. Each receptacle sub-assembly further includes an outer double-helix receptacle, generally concentric around the inner double-helix, formed from interleaved, coiled first and second bare wire ribbons and having an alterable inner circular cross-sectional area which can be enlarged and then contracted so as to easily receive and then provide constriction around a coaxial cable outer-conductor. Opposing first and second ribbons of the two opposed inner double-helixes are interconnected, respectively, by a first and second electrically conductive bridge. Opposing first and second ribbons of the two opposed outer double-helixes are interconnected, respectively, by a third and fourth electrically conductive bridge.
The first and second receptacle sub-assemblies further include, respectively, a first and second cylindrical insulating housing disposed on opposite sides of the base, which rigidly constrain the inner and outer double-helixes. Each housing is separately rotatable with respect to the base about a common axis in either rotational direction by applying a torque to a housing extension rigidly attached to the housing. Rotating a housing causes the attached inner and outer double-helix receptacles to enlarge or contract. Thus, each pair of double-helix receptacles are separately ganged to enable individual control for insertion or extraction of a coaxial cable end.
A second preferred embodiment includes opposed first and second receptacle sub-assemblies disposed, respectively, within first and second cylindrical sleeves, and separated by a cylindrical insulating base. Each receptacle sub-assembly includes an inner single-helix receptacle formed from a coiled bare wire and having an alterable inner circular cross-sectional area which can be enlarged and then contracted so as to easily receive and then provide constriction around a coaxial cable bared center-conductor. Each receptacle sub-assembly further includes an outer single-helix receptacle, generally concentric around the inner helix, formed from a coiled bare wire ribbon and having an alterable inner circular cross-sectional area which can be enlarged and then contracted so as to easily receive and then provide constriction around a coaxial cable bared outer-conductor. Ribbons of the two opposed inner helixes are interconnected by a first electrically conductive bridge. Ribbons of the two opposed outer helixes are interconnected by a second electrically conductive bridge.
The first and second receptacle sub-assemblies further include, respectively, a first and second cylindrical insulating housing disposed on opposite sides of the base, rigidly attached, respectively, to the first and second sleeves. The first and second inner helix receptacles are rigidly attached, respectively, to the first and second insulating housings; the first and second outer helix receptacles are rigidly attached, respectively, to the first and second sleeves. Each sleeve-housing combination is separately rotatable with respect to the base about a common axis in either rotational direction by applying a torque to the sleeve or housing. Such rotation causes the attached inner and outer helix receptacles to enlarge or contract. Thus, the housings and each pair of helix receptacles are separately ganged to enable individual control for insertion or extraction of a coaxial cable end.
A more complete understanding of the present invention and other objects, aspects and advantages thereof will be gained from a consideration of the following description of the preferred embodiments read in conjunction with the accompanying drawings provided herein.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. I is a partial sectional view of a first preferred embodiment, including opposed first and second inner double-helix receptacles, opposed first and second outer double-helix receptacles, first and second sleeve housings, a base, and opposed first and second housings.
FIG. 2 is a perspective view of conductive elements of the FIG. I embodiment, including first and second inner double-helix receptacles, first and second outer double-helix receptacles, and first, second, third and fourth bridges.
FIG. 3 is a perspective view of the FIGS. 1 and 2 first inner double-helix receptacle, first inner double-helix receptacle tabs, second outer double-helix receptacle, second outer double-helix receptacle tabs, base, and partial first and second bridges.
FIG. 4 is a partial sectional view of the FIG. 1 embodiment, including the first inner double-helix receptacle, first and second outer double-helix receptacles, base, first and second housings, and first and second housing extensions.
FIG. 5 is a perspective view of the FIG. 1 embodiment.
FIG. 6A is a perspective view of the FIG. 1 embodiment receiving a bared end from each of two opposing coaxial cables.
FIG. 6B is a perspective view of the coaxial cable ends inserted into the FIG. 1 embodiment.
FIG. 7 is a perspective view of the FIG. 4 first and second housing extensions modified to allow limited slippage between the inner double-helix receptacles and outer double-helix receptacles.
FIG. 8A is a perspective view of the FIG. 4 base, modified to include a first locking mechanism, and first and second housing extensions, and the FIG. 1 first and second sleeve housings.
FIG. 8B is a perspective view of the FIG. 4 base, modified to include a second locking mechanism alternative to the FIG. 8A locking mechanism, the FIG. 8A first and second housing extensions, and the FIG. 1 first and second sleeve housings.
FIG. 9 is a perspective view of the FIG. 4 base, first and second housings, and first and second housing extensions, and including a partial sectional view of an exterior outer-conductor.
FIG. 10 is a partial sectional view of a second preferred embodiment, including opposed first and second inner single-helix receptacles, opposed first and second outer-helix receptacles, opposed first and second sleeves, a base, and opposed first and second housings.
FIG. 11 is a perspective view of conductive elements of the FIG. 10 embodiment, including first and second inner helix receptacles, first and second outer helix receptacles, and first and second bridges.
FIGS. 12A-12F show six steps in constructing a double-helix receptacle such as those used in the FIG. 1 embodiment.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
I. INTRODUCTION
While the present invention is open to various modifications and alternative constructions, the preferred embodiments shown in the drawings will be described herein in detail. It is to be understood, however, there is no intention to limit the invention to the particular forms disclosed. 0n the contrary, it is intended that the invention cover all modifications, equivalences and alternative constructions falling within the spirit and scope of the invention as expressed in the appended claims.
II. FIRST PREFERRED EMBODIMENT
As shown in FIG. 1, a coupler 20 for connecting two opposing coaxial cable ends includes opposed first and second receptacle sub-assemblies 22 and 24. Sub-assembly 22 includes a first inner double-helix receptacle 26 formed from interleaved, coiled first and second bare wire ribbons 28A, 28B. Receptacle 26 has an alterable circular inner cross-sectional area which can be enlarged and then contracted so as to easily receive and then constrict around and tightly retain the bared center-conductor of a first coaxial cable within the receptacle 26. Sub-assembly 22 further includes a first outer double-helix receptacle 30, generally concentric around the inner receptacle 26, formed from interleaved, coiled first and second bare wire ribbons 32A, 32B. Receptacle 30 has an alterable circular inner cross-sectional area which can be enlarged and then contracted so as to easily receive and then constrict around and tightly retain the outer-conductor of the first coaxial cable within the receptacle 30.
Sub-assembly 24 includes a second inner double-helix receptacle 34 formed from interleaved, coiled first and second bare wires 36A, 36B. Receptacle 34 has an alterable circular inner cross-sectional area which can be enlarged and then contracted so as to easily receive and then constrict around and tightly retain the bared center-conductor of a second coaxial cable within the receptacle 34. Sub-assembly 24 further includes a second outer double-helix receptacle 40, generally concentric around the inner receptacle 34, formed from interleaved, coiled first and second bare wire ribbons 42A, 42B. Receptacle 40 has an alterable circular inner cross-section which can be enalrged and then contracted so as to easily receive and then constrict around and tightly retain the outer-conductor of the second coaxial cable within the receptacle 40.
Sub-assemblies 22 and 24 further include, respectively, generally cylindrical first and second sleeve housings 46 and 48, having first and second interior surfaces 49A and 49B, and concentric about and closely receiving, respectively, the outer receptacles 30 and 40.
As best shown in FIG. 2, ribbon 32A of outer receptacle 30 is rigidly connected to ribbon 42A of outer receptacle 40 at their opposed proximal ends by a first electrically conductive bridge 50A. Ribbon 32B of outer receptacle 30 is rigidly connected to ribbon 42B of outer receptacle 40 at their opposed proximal ends by a second electrically conductive bridge 50B. The outer receptacles 30 and 40 are rigidly connected at their opposite distal ends to diametrically opposed first and second outer-conductor helix tabs 52A, 52B and 54A, 54B, respectively.
Ribbon 28A of receptacle 26 is rigidly connected to ribbon 36A of inner receptacle 34 at their opposed proximal ends by a third electrically conductive bridge 60A. Ribbon 28B of inner receptacle 26 is rigidly connected to ribbon 36B of inner receptacle 34 at their opposed proximal ends by a fourth electrically conductive bridge 60B. The inner receptacles 26 and 34 are rigidly connected at their opposite distal ends to diametrically opposed first and second center-conductor helix tabs 65A, 65B and 68A, 68B, respectively.
FIG. 3 shows a generally cylindrical insulating base 72 having a first surface 74A and an opposing parallel second surface 74B (not shown). First and second half-sections 82A and 82B include, respectively, arcuate slots 84B and 84A extending between surfaces 74A and 74B (not shown). The slots 84A and 84B closely receive, respectively, first and second bridges 50A and 50B. First and second half-sections 82A and 82B further include, respectively, slots 86A and 86B extending between surfaces 74A and 74B. The slots 86A and 86B closely receive, respectively, the third and fourth bridges 60A (not shown) and 60B (not shown).
FIG. 4 shows first and second generally cylindrical insulating housings 90 and 92 fitting and rotating against, respectively, first and second smooth surfaces 94A and 94B (not shown) of base 72. The housings 90 and 92 are closely received, respectively, within the bridges 50A and 50B interconnecting receptacles 30 and 40. Inner receptacle 26 and inner receptacle 34 (not shown) are closely received, respectively, within bore 96 and bore 98 (not shown) of housings 90 and 92. Housings 90 and 92 are rigidly attached over a limited portion of their circumference to, respectively, first and second housing projections 100 and 102.
Referring to FIGS. 2 and 4, tabs 65A, 65B and 68A, 68B are closely received, respectively, within diametrically opposed slots 104A, 104B and 106A, 106B (not shown) in opposing distal surfaces 108 and 110 (not shown) of housings 90 and 92, respectively. Rigidity of bridges 60A and 60B within base 72 and constraints imposed on the distal ends of receptacles 26 and 34 by tabs 65A, 65B and tabs 68A, 68B, respectively, combine to cause inner helical receptacle 26 or 34 to coil or uncoil when housing 90 or 92 undergoes a rotational displacement about axis 8-8'.
FIG. 5 shows first and second housing projections 100 and 102 including, respectively, an end 114 and 116 extending, respectively, through slots 118 and 119 of sleeve housings 46 and 48. The sleeve housings 46 and 48 can be fabricated from solid metal, an insulating material, or a dielectric material within a metal skin.
Referring to FIGS. 4 and 5, tabs 52A, 52B and 54A, 54B are rigidly received within slots at the distal ends of sleeve interior surfaces 49A and 49B (not shown). Rigidity of bridges 50A and 50B within base 72 and constraints imposed on the distal ends of the outer receptacles 30 and 40 by tabs 52A, 52B and 54A, 54B, respectively, combine to cause outer-helical receptacle 30 or 40 to coil or uncoil when sleeve housing 46 or 48 undergoes a rotational displacement about axis 8-8'. The helix pairs 30, 26, or 40, 34 (not shown), are conveniently enlarged or contracted by gripping the base 72 and applying a twisting force to sleeve housing 46 or 48.
The helical ribbons of the inner and outer receptacles can be wound either right-handed or left-handed. In FIG. 2, (28A, 28B) and (32A, 32B) are wound left-handed, while (36A, 36B) and (42A, 42B) are wound right-handed. Configurations for the ribbon pairs can mix the left- and right-handed windings. However, (28A, 28B), (32A, 32B) or (36A, 36B), (42A, 42B) must be wound in the same direction in order that the inner and outer helix pairs expand or contract together.
FIG. 6A shows the coupler 20 ready to receive a bared end 120A, 120B from each of two opposed coaxial cables 122A and 122B. The cable ends 120A, 120B include, respectively, a bared center-conductor 124A, 124B, a dielectric 126A, 126B, an outer wire-braid shield 128A, 128B, and an outer insulating sheath 130A, 130B.
FIG. 6B shows the coaxial cables 122A and 122B inserted into coupler 20, with cable 122A seated and locked within a region 132A of the coupler and cable 122B seated within a region 132B of the coupler. The proximal ends of the sheaths 130A, 130B are disposed external to the coupler 20.
Other types of conductors that can be contacted with a coupler of the present invention instead of the wire-braid shields 128A, 128B of FIGS. 6A and 6B include the outer conductor of a male-end connector such as the outer shield of an RCA (phono) plug, UHF-type plug, N-type plug, and any coaxial male end connector assembly having an outer conductive member and a central pin or plug.
In some circumstances, especially when utilizing helixes fabricated from resilient conducting material, a limited amount of slippage between the inner and outer helixes may be desirable to allow uniform compression of the inner and outer receptacles on, respectively, a coaxial cable center-conductor and an outer conductive shield. Such slippage may be achieved by any number of methods, such as allowing movement of the helix tabs within their respective restraining slots, or by allowing substantial rotational movement of housing projections 100 and 102 within sleeve housings 46 and 48.
FIG. 7 shows a modified configuration 20A of the coupler 20 wherein first and second housing projections 100A and 102A are able to move rotationally within slots 118 and 119 of sleeve housings 46 and 48, thereby providing limited slippage between either set of (inner, outer) receptacle pairs.
Referring to FIGS. 2 and 7, limited slippage between helix pairs 28A, 28B and 32A, 32B or 36A, 36B and 42A, 42B allows the continued travel of one helix after the other helix has constricted around its respective conductor.
FIG. 8A illustrates a first preferred method of locking housing projections 100 or 102 of coupler 20B in place, in order to keep the helix-pairs tightly constricted around their respective coaxial cable conductors. A cylindrical pin 140 inserted into one of a plurality of holes 142 in a modified base 72A prevents rotation of housings 90 and 92 (not shown) with respect to base 72A. Pin 140, retained by friction within any of the holes 142, may be threaded and subsequently screwed into a threaded hole. A single pin may be used within a hole 142 to lock both housing projections 100 and 102. Alternatively, two pins may be inserted in different holes 142, on opposing surfaces of 72A, to accommodate different angular positions of projections 100 and 102. For couplers having helix receptacles fabricated from non-resilient material, such locking is required to maintain constriction and coupling in the absence of an external torque. Couplers with receptacles fabricated from resilient material can utilize such locking mechanisms to ensure high coupling reliability, especially in strong shock and high vibration environments.
FIG. 8B shows a coupler 20C with a second preferred method of locking housing projections 100 and 102 in place. Base 72B includes first and second pluralities of depressible keys 144A and 144B disposed, respectively, around the periphery of surface 74A and surface 74B (not shown). Keys 144A, 144B are capable of being pushed flush to surface of 74A, 74B, respectively, so as to allow rotational movement of housing projections 100 and 102 past the keys. Housing projections 100 and 102 are closely received, respectively, between two of the keys 144A and 144B.
FIG. 9 shows a modified configuration 20D of the coupler 20 wherein first and second electrical outer-conductor shields 150, 152, conforming, respectively, to housing projections 100B, 102B, and housings 90A, 92A, are interposed between and contact, respectively, the housings and bridges 50A, 50B. A third generally cylindrical electrical outer shield 154 is generally concentric about a base 72C and is directly attached to bridge 50A and 50B, respectively, by a wire 156A and 156B. The base 72C includes first and second opposed parallel surfaces composed of shields 158A and 158B (not shown). Shields 158A and 158B are used in conjunction with 150, 152, and 154 to provide complete shield around base 72C, housing 90A and housing 92B (not shown). Addition of shielding can be extended to include the entire exterior surface of the coupler; the only provision for exterior shielding is that it does not contact the cable center-conductor. Such shielding acts to reduce radio-frequency emission-leakage at coupler junctions, and also provides a more homogeneous transition between two cables, as well as providing an even distribution of inductive and capacitive components of impedance. As different applications require different impedances, construction of a coupler will vary according to the specific application.
As an alternative to the normally closed configuration of the double-helix receptacles, the helix receptacles may be normally open with the locking mechanism as shown in FIGS. 8A or 8B keeping the helix receptacles closed after cables are inserted.
In addition, the coupler is not limited to a stand-alone configuration, but can also be panel-mounted or mounted within an electronics chassis.
III. SECOND PREFERRED EMBODIMENT
As shown in FIGS. 10 and 11, a coupler 200 for connecting a bared end from each of two opposing coaxial cables includes opposed first and second receptacle sub-assemblies 202 and 204. Sub-assembly 202 includes a first inner single-helix receptacle 206 formed from a coiled bare wire 208. Receptacle 206 has an alterable circular inner cross-sectional area which can be enlarged and then contracted so as to easily receive and then constrict around and retain the bared center-conductor of a coaxial cable within the receptacle 206. Sub-assembly 202 further includes an outer single-helix receptacle 210, generally concentric around the inner receptacle 206, formed from a coiled bare wire ribbon 212. Receptacle 210 has an alterable circular inner cross-sectional area which can be enlarged and then contracted so as to easily receive and then constrict around and retain the outer conductive shield of the first coaxial cable within the receptacle 210.
Sub-assembly 204 includes a second inner single-helix receptacle 214 formed from a coiled bare wire 216. Receptacle 214 has an alterable inner cross-sectional area which can be enlarged and then contracted so as to easily receive and then constrict around and retain the bared center-conductor of a second coaxial cable within the receptacle 214. Sub-assembly 204 further includes a second outer single-helix receptacle 218, generally concentric around the inner receptacle 214, formed from a coiled bare wire ribbon 220. Receptacle 218 has an alterable circular inner cross-sectional area which can be enlarged and then contracted so as to easily receive and then constrict around and retain the outer conductive shield of the second coaxial cable within the receptacle 218.
Sub-assemblies 202 and 204 further include, respectively, generally cylindrical first and second sleeve housings 222 and 224, having, respectively, first and second interior surfaces 226A and 226B (not shown), and concentric about and closely receiving, respectively, the outer receptacles 210 and 218. First and second interior surfaces 226A and 226B (not shown) have an inner diameter slightly larger than the diameter of outer receptacles 210 and 218 in their fully opened state. The outer receptacles 210 and 218 are rigidly connected at their opposite distal ends to outer-conductor helix tabs 228A and 228B, respectively. Tabs 228A and 228B are rigidly received, respectively, within slots 230A (not shown) and 230B (not shown) in the distal ends of sleeve interior surfaces 226A and 222B. Ribbon 212 of outer receptacle 210 is rigidly connected to ribbon 220 of outer receptacle 218 at the opposed proximal ends of outer receptacles 210 and 218 by a first electrically conductive bridge 232. Rotation of sleeve housing 222 or 224 and the subsequent rotation of tabs 228A and 228B, being rigidly connected at their distal ends to outer receptacles 210 and 218, relative to bridge 232, combine to cause outer helical receptacle 210 or 218 to coil or uncoil.
Referring to FIG. 10, the coupler 200 further includes a generally cylindrical insulating base 240 having opposed parallel first and second surfaces 242A and 242B (not shown). A first generally cylindrical insulating housing 244 and housing extension 245, including therethrough a central bore 246, is fitted against and is smoothly rotatable with respect to surface 242A. A second generally cylindrical insulating housing 248 and housing extension 249, including therethrough a central bore 250, is fitted against and is smoothly rotatable with respect to surface 242B (not shown). Housing extensions 248 and 249 have limited rotation within the area unobstructed by bridge 232. Bores 246 and 250 in housings 244 and 248 each have an outer diameter slightly larger than the diameter of inner receptacles 206 and 214 in their fully opened state.
As further shown in FIGS. 10 and 11, inner receptacles 206 and 214 rigidly connected, respectively, at their opposite distal ends to center-conductor helix tabs 254 and 256. Inner receptacles 206 and 214 are closely received, respectively, within bores 246 and 250 of housings 244 and 248. Tabs 254 and 256 are closely received, respectively, within slots 258 and 260 in opposing distal surfaces 272A and 272B (not shown) of housings 244 and 248, respectively. Ribbon 208 of inner receptacle 206 is rigidly connected to ribbon 216 of inner receptacle 214 at the opposed proximal ends of inner receptacles 206 and 214 by a second electrically conductive bridge 276. Rigidity of the inner receptacles 206 and 214 at their proximal ends due to bridge 276, and constraints imposed on their distal ends by tabs 254 and 256, respectively, combine to cause inner helical receptacle 206 or 214 to coil or uncoil when housing 244 or 248 undergoes rotational displacement with respect to base 240.
As in the first embodiment, the helical receptacles of coupler 200 can be wound in a right- or left-handed manner, provided that each (inner, outer) helix pair are wound in the same direction. The single-helix configuration, when constructed of a resilient conducting material, can be normally contracted or normally open. In addition, the single-helix configuration can include provision(s) for slippage, locking, shielding, and be chassis- or panel- mounted, all in a manner similar to provision(s) for the double-helix configuration.
IV. HELIX FABRICATION METHODS
Square, rectangular, or round stock may be used in fabricating inner single- or double-helix receptacles. Fabrication methods are similar to those described in the '726 patent which use a rotating rod-toolset to wrap a helix onto itself.
Fabrication of outer double helix receptacles according to the present invention is shown in FIGS. 12A-12F. Referring to FIG. 12A, two appropriately sized lengths 270A, 270B of an electrically conductive ribbon material are positioned alongside a rotating tool 272 including a catch 274. The ribbons 270A, 270B are caught in and bent within the catch 274.
In FIG. 12B, the ribbons are initially bent and suitably angled to provide an appropriate pitch. Alternatively, the shape of ribbons 270A and 270B can be stamped out from a sheet of appropriate conductive material, thereby bypassing the bending step between steps 12A and 12B. A stamped-out form of this nature can provide any desired shape and contour to support the pitch and dimensional requirements of the helix.
FIGS. 12C, 12D and 12E show three successive stages in forming an outer double-helix receptacle as the tool 272 undergoes axial rotation. FIG. 12F shows a fully-formed double-helix receptacle 276 including first and second tabs 278A, 278B.
The electrically conductive material used for inner or outer-helix fabrication can be resilient or non-resilient. The type of material used depends on intended applications of a particular coupler. | A coupler of the zero insertion force (ZIF) type for connecting two coaxial cables. A first embodiment includes a pair of opposed (inner) cylindrical receptacles, electrically connected, each formed from two lengths of helically coiled, interleaved wire, which each receive and grip a cable center-conductor. A pair of opposed (outer) cylindrical receptacles, electrically connected, each formed from two lengths of helically coiled, interleaved wire ribbon, each receive, contact, and grip a cable outer-conductor. The first embodiment further includes means for concurrently enlarging or contracting each (inner, outer) receptacle pair, and means for maintaining receptacle contraction. A second embodiment includes a pair of opposed (inner) cylindrical receptacles, electrically connected, each formed from a length of helically coiled wire, which each receive, contact and grip a cable center-conductor. A pair of opposed (outer) cylindrical receptacles, electrically connected, each formed from a length of helically coiled wire ribbon, each receive and grip a cable outer-conductor. The second embodiment further includes means for concurrently enlarging or contracting each (inner, outer) receptacle pair, and means for maintaining receptacle contraction. | 7 |
CLAIM FOR PRIORITY
This application claims priority to International Application No. PCT/EP01/12367 which was published in the English language on Jun. 14, 2002.
TECHNICAL FIELD OF THE INVENTION
The invention relates to a method for transmitting data with a reduced bandwidth in which the quantity of the data to be transmitted over a data transmission network is reduced by a reduction method.
BACKGROUND OF THE INVENTION
The data is transmitted in data packets or in transmission channels with a fixed bandwidth in the data transmission network. The data packets are usually of a permanently predefined size. Information relating to the destination is specified in a packet header. The user information data to be transmitted is located in a packet body.
During the transmission in transmission channels, in the simplest case a line is used for each user information connection. However, a plurality of user information connections are usually transmitted over one transmission link, fixed time windows being predefined in one time frame for the transmission of the user information data of a user information channel.
As a result of opening the telecommunications market, there are network operators which do not have their own transmission links or switching devices. FIG. 1 shows a telecommunications network 10 whose operator has leased the greater part of the switching and transmission equipment from a conventional network operator and which is therefore referred to below as a new operator. The telecommunications network 10 contains three local switching offices 12 to 16 which are associated with the conventional network operator and are used by the new operator. The network operator of the telecommunications network 10 also has leased transmission links 20 to 26 from the conventional network operator. The transmission link 20 connects the local switching office 12 to a subscriber line concentrator 30 to which a multiplicity of subscribers are connected, two subscribers Tln 1 and Tln 2 of which are shown in FIG. 1 . A telecommunications system 32 , which is used by a private company for toll-free switching of connections within the company's premises being also connected to the concentrator 30 . The concentrator 30 has also been leased by the conventional network operator. A PCM30 (pulse code modulation) system, for example, is used for transmission on the transmission link 20 .
The transmission link 22 connects the local switching office 14 to a subscriber line concentrator 34 to which a multiplicity of subscribers are also connected, subscribers Tln 3 and Tln 4 of which are illustrated in FIG. 1 . A telecommunications system 36 is connected directly to the local switching office 14 via a transmission link 38 .
The transmission link 24 lies between the local switching offices 12 and 14 . The local switching offices 14 and 16 are connected using the transmission link 26 . A telecommunications system 40 is connected to the local switching office 16 via the public telecommunications network 42 . Voice data according to the ISDN (Integrated Services Digital Network) standard are transmitted in the public telecommunications network 42 .
The network operator of the telecommunications network 10 attempts to utilize the leased transmission links 20 to 26 as well as possible. Compression algorithms for voice are defined, for example, in the standards of the ITU-T (International Telecommunication Union—Telecommunication), for example in the Standards G.723 to G.729. According to the standards, the voice information to be switched within the scope of a normal voice connection can be reduced to bit rates of up to 8 kbit/s on certain links or sections without a disruptive loss of voice quality. This permits a basic channel with a bit rate of 64 kbit/s to be used for transmitting up to eight voice connections. If facsimile data, program data or file data are transmitted over a connection, suitable measures can also be taken to reduce the bandwidth.
The voice quality of a connection depends in particular on the following factors:
falsification due to voice processing, for example due to voice compression/decompression, delays due to transmission, packetizing and/or voice processing, echo effects, and information losses, for example due to transmission errors or due to losses of packets or cells.
Multiple transcoding leads to audible degradations in the voice quality, for example to:
voice noise and relatively large voice falsifications, reduction in the clarity and comprehensibility, the increased difficulty in recognizing the speaker by his voice, and listener and speaker echo owing to the relatively long delay times in the transmission of transcoded voice.
Multiple transcodings are therefore to be avoided as much as possible.
However, multiple transcodings occur to an increasing degree due to the following causes:
connections are switched between different networks, the use of reduction methods in private networks, and the inclusion of new techniques in voice transmission, for example voice transmission over the Internet.
SUMMARY OF THE INVENTION
It is an aspect of the invention to transmit data with a reduced bandwidth according to a simple method whose use avoids multiple transcodings. In addition, an associated switching device and an associated remote connection unit are provided.
According to an aspect of the invention, a method for transmitting data with a reduced bandwidth, in which the quantity of data to be transmitted over a data transmission network is reduced is provided. The type of reduction is signaled by a source switching device for switching data in the data transmission network to a terminal switching device of the data transmission network. The data processed by the reduction method is transmitted to the terminal switching device. The transmitted data is processed as a function of the signaling using a partner method which is associated with the reduction method and which restores the original data in unchanged form or in an essentially equivalent form.
According to an aspect of the invention, the type of reduction is signaled from a source switching device for switching data in a data transmission network to a terminal switching device of the data transmission network. The data which is processed by the reduction method is transmitted to the terminal switching device. The transmitted data is processed as a function of the signaling using a partner method which is associated with the reduction method and which restores the original data in identical form or an essentially qualitatively equivalent form.
The signaling of the type of reduction to the following switching device in the transmission link ensures that one of a plurality of reduction methods can optionally be used and nevertheless the associated partner method can be determined. In the next switching office, in particular a further reduction with the same method as would be the case for the section-by-section reduction and immediate execution of the partner method at the end of a section, can also be avoided.
According to an aspect of the invention, the partner method is executed only in the terminal switching device. The terminal switching device determines, by reference to the destination of the data to be transmitted, that the partner method is to be executed by the terminal switching device itself. In switching devices upstream of the terminal switching device along the transmission link, it is detected, by reference to the destination call number, that the partner method is not yet to be executed.
According to another aspect of the invention, multiple transcoding with the same reduction method along the transmission link can be avoided. The consequence is an improved transmission quality, in particular an improved voice quality.
The bandwidth of the data to be transmitted is reduced by the use of the reduction method. The transmission capacity of transmission links in the data transmission network and thus the transmission capacity of the data transmission networks can consequently be used very well. In particular, on leased transmission links, the use of the method according to the invention leads to better use of the transmission capacity with a simultaneously high transmission quality. According to another aspect of the invention, the reduction method is carried out in the source switching device. The partner method is carried out in the terminal switching device. The terminals can remain unchanged as a result of this measure.
According to another aspect of the invention, the reduction method used is either a method for demodulating fax data, a method for compressing voice data or a method for handling the TFO (Tandem Free Operation) mode. The selection is carried out automatically. A selection unit monitors the data transmitted on the transmission link and selects a suitable reduction method as a function of the data type. The selection method senses the signal tones of various fax devices and modems. If a device is not detected, the fax data is transmitted without processing by the reduction method. The selection unit also contains devices with which a transmission mode for mobile radio data in a fixed network can be detected, said mode also being known under the name “TandemFree Operation”, abbreviated as TFO mode. In this mode, stop data are added to user information data with a bandwidth of 32 kbit/s so that the bandwidth of 64 kbit/s required for transmission in the fixed network is produced. In order to be able to take the TFO mode into account, what is referred to as a TRAU unit Transcoder/Rate Adapter Unit), such as is usually used only at a network gateway between the fixed network and the mobile radio network, is arranged in the selection unit.
According to a further aspect of the invention, the data processed by the reduction method is first transmitted from the source switching device to a transit switching device of the data transmission network. The signaling also initially takes place from the source switching device to the transit switching device, and only then from the transit switching device to the terminal switching device. Stop data is added to the transmitted data in the transit switching device. The data processed using the reduction method is transmitted together with the stop data from the transit switching office to the terminal switching device. While the first transmission section between the source switching device and the transit switching device is effectively utilized in terms of its bandwidth, a higher transmission capacity is required on the second transmission section from the transit switching device to the terminal switching device and is actually necessary. This results in a situation in which it is possible to dispense with transmitting the data with specific modules in multiply used basic channels in the transit switching device. Methods in which there are a plurality of transit switching devices between the source switching device and terminal switching device can also be applied.
According to yet a further aspect of the invention, it is possible to detect, in the switching devices downstream of the source switching devices, that stop data has been added on the basis of the signaling and the transmission bandwidth of the incoming transmission channel. This stop data can be removed in the switching devices which pass through, if corresponding units are present. The following transmission sections can thus again be utilized better in terms of the bandwidth. If appropriate, stop data which is still present is to be removed in the end switching device. Only then is the partner method executed.
In one development, if the switching devices are switching offices in a switched telecommunications network, the signaling takes place inside or outside the transmission channel used for the user information data. The signaling of the type of reduction is carried out in particular using a signaling protocol for the signaling between switching offices. At present, signaling data is increasingly being exchanged between switching offices in accordance with the international signaling protocol No. 7 which was produced by the ITU-T (International Telecommunication Union—Telecommunication Standardization Sector) or its predecessor the CCIT (Commité Consultatif International Télégraphique et Téléphonique). The signaling of the type of reduction can be carried out, for example, by using already defined parameters, not used in the telecommunications network, of the signaling protocol number 7. In particular, the signaling of the type of reduction can advantageously be integrated into protocol-based signaling systems. Signaling which takes place in the user information channel is in principle conceivable but is associated with considerable limitations owing to the restriction on the information which can be signaled.
In another development, transmission links on which the data processed by means of the reduction method are transmitted with a reduced bandwidth are preferably characterized by a network administration center in such a way that these transmission links are known to the controller of a switching device or switching office. The execution of the partner method is in this case also controlled as a function of the prescriptions for the transmission links. This procedure makes it possible to inform a multiplicity of switching offices of the respective transmission links in a simple way.
The switching devices are generally only capable of switching channels with a specific switching bandwidth. For this reason, stop data is added to the data in transmission channels with a smaller bandwidth than the switching bandwidth before the switching operation. This stop data is either removed again immediately after the switching operation, if the user information data is to be transmitted with a reduced bandwidth, or remains with the user information data if it is not necessary to pay attention to the bandwidth during the transmission over the next transmission link.
The invention also relates to switching devices and a remote connection unit for carrying out the method according to the invention and to its developments. In this way, the abovementioned technical effects also apply to the switching device and to the remote connection unit.
The remote connection unit according to the invention is used in the method according to the invention for switching connections with a reduced bandwidth. The remote connection unit is either connected directly to a connection unit in which the method according to the invention or one of its developments is executed, or alternatively the remote connection unit is connected to a connection unit of a switching office which does not carry out the method steps according to the inventive method. However, the switching office contains connection units which execute the method according to the invention or its developments. Connections are switched with double use of a main switching matrix of the switching device both via a connection unit which carries out the method steps according to inventive methods and using a connection unit which does not carry out the inventive method. This measure makes it possible to bundle the connections of a plurality of connection units according to the invention. In addition, switching twice in the switching matrix brings about greater flexibility.
The invention will be explained below with reference to the appended drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a telecommunications network.
FIG. 2 shows a switching office having a plurality of subscriber line modules,
FIG. 3 shows a subscriber line module having a plurality of connection units,
FIG. 4 shows the signaling of the type of reduction and thus also the required transmission capacity between the switching offices,
FIG. 5 shows switching processes in a switching office, and
FIG. 6 shows a unit which is remote from a switching office.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 2 shows, in a telecommunications network 50 , a switching office 52 , also abbreviated to SWO, having a plurality of subscriber line modules 54 and 56 . The subscriber line modules are also referred to in English as “line trunk group”, abbreviated to LTG. Further subscriber line modules are indicated by points 58 .
A connecting line 60 connects the switching office 52 to a concentrator unit 62 . Digitized voice data, for example, according to the PCM30 (pulse code modulation) standard are transmitted on the connecting line 60 in 30 basic channels which each have a transmission capacity of 64 kbit/s. The connecting line 60 ends at the subscriber line module 54 , which is used to connect lines which come from subscribers, for example from a subscriber Tln 5 . A further connecting line 64 which is connected to the subscriber line module 54 leads, for example, to a telecommunications system (not illustrated). The subscriber line module 54 is of similar design to the subscriber line module 56 , whose design is explained below with reference to FIG. 3 .
A connecting line 66 connects the subscriber line module 56 to a switching office 68 . Voice data, for example according to the PCM30 standard but in a bandwidth-reduced form, is transmitted on the connecting line 66 . The reduction in the bandwidth is represented below by double lines.
The switching office 52 also contains a main switching matrix 70 and a central processor 72 . All the subscriber line modules 54 to 56 are connected to the main switching matrix 70 via connecting lines, connecting lines 76 and 78 of which are illustrated in FIG. 2 .
Each connecting line 76 , 78 has a transmission capacity of, for example, eight Mbit/s so that in each case voice data or control data can be transmitted over 128 transmission channels with a bandwidth of 64 kbit/s. The central processor 72 controls the switching of connections in the switching matrix 70 . For example, the central processor 72 switches a voice channel 80 via which a subscriber Tln 5 which is connected to the switching office 52 can speak with a subscriber Tln 6 connected to the switching office 68 . A signaling channel 82 is used by the subscriber line module 54 to transmit control data to the central processor 72 before the connection set-up. After the switching of the connection using the voice channel 80 , further control data is exchanged between the subscriber line module 54 and the central processor 72 . Control data is exchanged via a signaling channel 84 between the subscriber line module 56 and the central processor 72 .
The voice channel 80 and the signaling channels 82 , 84 have a transmission capacity of, for example, at least 64 kbit/s if the main switching matrix 70 is only capable of switching connections with such a bandwidth (switching bandwidth).
FIG. 3 shows the design of the subscriber line module 56 which contains four connection units, two connection units 100 and 102 of which are illustrated in FIG. 3 . Further connection units are indicated by points 104 . The connecting line 66 is connected to the connection unit 100 . A connecting line 105 on which compressed voice data is transmitted is connected to the connection unit 102 , a plurality of user information channels being transmitted in a basic channel with a bandwidth of 64 kbit/s.
The subscriber line module 56 also contains a group switching matrix 106 and a group processor 108 . The connection units 100 , 102 are connected to the group switching matrix 106 via connecting lines 110 , 112 so that connections between the connection units 100 , 102 and an interface 114 can be switched in the group switching matrix 106 . The interface 114 is connected to the group switching matrix 106 via a connecting line 116 and to the group processor 108 via a connecting line 118 . The connecting line 76 is connected to the other side of the interface 114 .
The connection illustrated in FIG. 2 for the call between the subscribers Tln 5 and Tln 6 is switched using a connection 119 in the group switching matrix 106 . The connection units 100 , 102 are connected to the group processor 108 via a BUS system (not illustrated). The group processor 108 also controls the switching of connections in the group switching matrix 106 via the BUS system.
The subscriber line module 56 contains a signal unit 120 which contains, inter alia, a sound generator, a time pulse generator and a dual tone multi frequency (DTMF) receiver. The signal unit 120 is connected via connections (not illustrated) to the connection units 100 , 102 , the group switching matrix 106 and to the group processor 58 .
In addition, the subscriber line module 54 contains a storage unit 122 which is connected via a BUS 124 to the group processor 108 . Programs during whose processing by the group processor 108 the signaling and the connection control are implemented are stored in the storage unit 122 .
A compression unit 132 monitors the data switched in the group switching matrix 106 and selects a suitable reduction method as a function of the switched data type. Voice data is compressed. Fax data is demodulated and transmitted with a reduced bandwidth. Data in the TFO mode is also suitably processed.
FIG. 4 shows the signaling of the compression method and, thus, also of the required transmission capacity between the switching offices 52 , 68 and switching offices 200 , 202 . The switching office 68 contains not only a main switching matrix 204 but also a subscriber line module 206 connected to the connecting line 66 , as well as a subscriber line module 208 . The subscriber line module 208 is connected to a connecting line 210 which leads from the switching office 68 to the switching office 200 . In the switching office 200 , the connecting line 210 is connected to a subscriber line module 212 which transmits user information data which is incoming on the connecting line 210 to a main switching matrix 214 of the switching office 200 . There is also a subscriber line module 216 in the switching office 200 .
The switching office 202 contains a main switching matrix 218 and two subscriber line modules 220 and 222 . The switching offices 200 and 202 are connected to one another by means of a connecting line 224 , one of whose ends is connected to the subscriber line module 216 and the other end of which is connected to the subscriber line module 220 .
It will be assumed that the subscriber Tln 5 which is connected to the switching office 52 has set up a connection to a subscriber Tln 7 , which is connected to the switching office 202 . The switching office 52 is therefore referred to below as a source switching office. The switching office 202 is referred to as a terminal switching office. The switching offices 68 and 200 are transit switching offices which lie between the source switching office 52 and the terminal switching office 202 . The connection between the subscriber Tln 5 and Tln 7 must be set up via the connecting lines 66 and 224 which have been leased by another network operator. For this reason, the data must be transmitted on the connecting lines 66 and 224 in a compressed form. The user information data is transmitted on the connecting line 210 in compressed form together with stop data in user information channels with a bandwidth of 64 kbit/s. This is represented by two continuous lines which are parallel to one another, and one dashed line parallel thereto.
As explained above with reference to FIG. 3 , the subscriber line module 56 contains a compression unit 132 . In the transmission direction from the subscriber Tln 5 to the subscriber Tln 7 , the compression unit 132 operates as a voice compression unit, demodulation unit or bandwidth reduction unit, depending on the data to be transmitted. As a result of the compression carried out in the compression unit 132 , it is possible to transmit a plurality of user information channels with a transmission bandwidth of, for example, 16 kbit/s each in a basic channel with a transmission capacity of 64 kbit/s on the connecting line 66 to the switching office 68 . The connecting line 66 was characterized, from a network maintenance center (not illustrated) in the switching center 52 and in the switching office 68 , as a connecting line on which data with a reduced bandwidth is transmitted.
If what is referred to as a transparent connection is requested by the subscriber Tln 5 , that is to say a connection which is to expressly have a bandwidth of 64 kbit/s, such a connection is also set up in the switching office 52 . The compression unit 132 is not used for such connections. If, on the other hand, a voice connection or a 3.1 kHz audio connection is requested, the voice compression and the bandwidth reduction take place in the compression unit 132 . The bandwidth reduction takes place either at fixed subrates of 64 kbit/s or in packet-oriented fashion. In the latter case, the channel structure or subchannel structure of the connecting line 66 is generally eliminated. In particular, when silence suppression is applied, the packet-oriented bandwidth reduction is preferred. If the connection temporarily becomes a fax/modem connection, the voice processing in the compression unit 132 is switched off. The signaling data of the fax device or of the modem is switched on. This is possible because the compression unit has control over the fax or modem protocols which are usually used. By demodulating the sound signals coming from the fax device or from the modem, the transmission bandwidth can be reduced if the connected device transmits with a transmission rate which is less than 64 kbit/s.
If the subscriber Tln 5 is in a mobile radio network and if the compression unit 132 detects the TFO (Tandem Free Operation) mode of place, stop data which is already added at another place is removed again by the compression unit 132 .
If the switching office 52 is a network gateway between the mobile radio network and fixed network, the compression unit 132 prevents stop data from being inserted despite the TFO mode during the transmission in the fixed network. To transmit on the connecting line 66 , only one channel with a bandwidth of less than 64 kbit/s is required, for example of 32 kbit/s.
From the source switching office 52 , the method which has been carried out for bandwidth reduction in a respective channel by the compression unit 132 , cf. arrow 225 , is signaled using the signaling protocol to the switching office 68 . Signaling is carried out for each logic channel number used on the connecting line 66 .
The compressed data transmitted on the connecting line 66 is received in the subscriber line module 206 .
Owing to the administrative characterization of the connecting line 66 , the data received on the connecting line 66 is already processed. Initially, the data is divided up according to user information channels. Subsequently, stop data is added to the user information data in each user information channel using adaptation units 226 so that a bandwidth of 64 kbit/s is obtained. Then, the user information data and the stop data are switched via the main switching matrix 204 and the subscriber line module 208 , as in a known switching office. With packet-oriented bandwidth reduction, a 64 kbit/s channel is used exclusively for switching onward the arriving packets of a specific connection in the switching office 204 .
Within the scope of inter-office signaling between the switching offices 52 and 68 , the source switching office 52 signals in particular the type of voice compression and thus, inter alia, also the required net bandwidth during the setting up of a connection to the following switching office 68 . The transit switching office 68 detects through use of the destination call number that it is a transit switching office and thus that no voice decompression, fax/modem remodulation or processing in terms of the TFO method is necessary. The outgoing connecting line 210 was not administratively characterized as a connecting line on which data with a reduced bandwidth have to be transmitted. For this reason, the stop data is not removed on the output-end subscriber line module 208 . The compressed user information data is transmitted to the switching office 200 together with the stop data in 64 kbit/s channels via the connecting line 210 .
Within the scope of the inter-office signaling, in addition to the previously used signaling data, the switching office 68 signals onward to the switching office 200 the type of compression and the net bandwidth of the data received by the source switching office 52 , cf. arrow 228 .
Owing to the forward signaling of the compression type of the connection and the fact that the user information data arrives via an input-end connecting line 210 which is not optimized in terms of bandwidth, the switching office 200 is capable of detecting the content of the 64 kbit/s channel coming from the transit switching office 68 as compressed data with stop data. The output-end connecting line 224 is determined by the destination call number. As already mentioned, the connecting line 224 is characterized as a connecting line on which the data can be transmitted with a reduced bandwidth. As the data is already present in a compressed form, only the stop data is removed from the respective channels in the subscriber line module 216 using an adaptation unit 230 .
The switching office 200 signals the type of compression in a respective channel and the associated, actually required transmission bandwidth to the switching office 202 , cf. arrow 232 . The terminal switching office 202 detects by reference to the destination call number that the subscriber Tln 7 is connected within its own subscriber line region. Owing to the forward signaling of the type of compression, the terminal switching office 202 is capable of carrying out, in the input-end subscriber line module 220 , a partner method of the method carried out in the subscriber line module 56 for bandwidth reduction. The partner method is carried out in a decompression unit 234 which is located on the subscriber line module 220 . Depending on the type of bandwidth reduction, either voice decompression, voice pause generation or fax/modem remodulation is carried out in the decompression unit 234 . In this way, the transmitted data is essentially restored to its original form which was present when the data was generated by the subscriber Tln 5 .
The method explained by reference to FIG. 4 ensures that excess transcodings do not occur in the transit switching offices 68 and 200 . Voice data and fax data are transmitted in a way which is optimized in terms of the bandwidths. In addition, codings can be supported in the sense of a tandem-free operation. If the terminal switching office 202 is a network gateway between the fixed network and a network with mobile subscribers, then, in the decompression unit 234 , the signal which is received via the connecting line 224 is passed on without being changed to the mobile radio network. Stop data do not have to be removed.
In a similar way to that explained with reference to FIG. 4 , the data generated by the subscriber Tln 7 is directed via the terminating switching office 202 , the transit switching office 200 , 68 and the source switching office 52 to the subscriber Tln 5 . However, a compression unit (not illustrated) which corresponds to the compression unit 132 is used in the subscriber line module 220 . Stop data is added in the adaptation unit 230 . Stop data is removed in the adaptation unit 226 and the partner method associated with the method for reducing the bandwidth is carried out in a decompression unit, corresponding to the decompression unit 234 , of the subscriber line module 56 . If the subscriber Tln 7 calls the subscriber Tln 5 , signaling of the type of compression and of the required transmission bandwidth takes place in the direction opposite to the direction illustrated by the arrows 225 , 228 and 232 .
FIG. 5 shows switching operations in the switching office 68 . The subscriber line module 206 is of similar design to the subscriber line module 56 . However, the subscriber line module 206 does not necessarily contain a unit corresponding to the compression unit 132 . The subscriber line module 206 contains four connection units 250 to 256 for connecting various connecting lines. The connecting line 66 is connected to the connection unit 250 . At the output end, the connection unit 250 is connected via a line 258 to a group switching matrix 260 of the subscriber line module 206 . The adaptation unit 226 is located between the connecting line 258 and the group switching matrix 260 . In addition, the subscriber line module 206 contains an interface 262 with the main switching matrix 204 .
The design of the subscriber line module 208 corresponds essentially to the design of the subscriber line module 206 . An interface 264 forms the connection point to the main switching matrix 204 . A group switching matrix 266 in the subscriber line module 208 has the same design and the same function as the group switching matrix 260 . In addition, the subscriber line module 208 contains four connection units 270 to 276 . The connecting line 210 is connected to the connection unit 274 . A connecting line 278 is connected to the connection unit 272 and leads to a further switching office (not illustrated).
A channel structure 280 on the connecting line 66 was defined administratively by a network maintenance center. The PCM30 system on the connecting line 66 was divided into logic transmission channels with a transmission rate which is less than 64 kbit/s. The channels with a reduced transmission rate typically have a transmission bandwidth of n×8 kbit/s, n being a natural number greater than 1. In the exemplary embodiment, a reduced bandwidth of 16 kbit/s per user information channel was selected. For this reason, from a logical point of view, there are user information channels K 1 to K 120 on the PCM30 system 120 . In each case, four user information channels are transmitted in a physical channel P 1 to P 31 with a transmission bandwidth of 64 kbit/s. For example, the four user information channels K 1 to K 4 are transmitted in the physical PCM channel P 1 . The physical channel P 16 can, in principle, be used for the transmission of signaling data and is not divided here into logic channels with a reduced transmission bandwidth.
During the signaling, the user information channels K 1 to K 120 are designated by their logic channel number. If a channel is seized on a connecting line which is set up in this way, the transmission rate of the designated channel and its physical position are determined from the logic channel number in the subscriber line module 206 .
In the adaptation unit 226 , the incoming two bit-long user information data words of the designated channel are written in a predefined fashion into a data word of a 64 kbit/s channel of a PCM frame with a word length of eight bits. Stop data is written into the remaining bit places, for example, by assigning the value zero for the bit places to be filled in. Subsequently, the eight bit-long data words in the switching office 68 are transmitted from the group switching matrix 260 to the main switching matrix 204 via the interface 262 . A data word 280 which is generated by the adaptation unit 226 contains voice data of the user information channel K 1 in the first two places. The further six places of the data word 280 are filled with stop data X. A data word 282 contains user information data of the user information channel K 6 in the first two bit places. The further bit places of the data word 282 are filled with stop data X. In this way, only data words of a bit length of eight bits in channels which are to be switched through with a transmission rate of 64 kbit/s pass from the subscriber line module 206 to the main switching matrix 204 .
After the data words 280 and 282 have been switched in the main switching matrix 204 , they are transmitted in unchanged form as data words 284 and 286 to the subscriber line module 208 and switched to one of the connection unit 270 to 276 in the group switching matrix 266 on the basis of the destination call number. The data word 284 , which corresponds to the data word 280 , is switched to the connection unit 274 and transmitted to the switching office 200 in a physical channel P 1 with a transmission rate of 64 kbit/s. The data word 286 passes to the connection unit 272 and is transmitted in a physical channel P 2 on the connecting line 278 with a transmission rate of 64 kbit/s.
The switching function of the switching office 68 thus remains unchanged in comparison with the function of conventional switching offices. The conversion between the logic channel number and physical position is defined administratively so that the switching functions of the switching office 52 are not affected. The conversion between logic channel number and physical position itself then takes place exclusively in the connection units, for example in the connection unit 250 .
FIG. 6 shows a unit 300 which is remote from the switching office 52 and which can be used to carry out the compressed transmission over a connecting line 302 , although a following switching office 304 does not have a subscriber line module which is suitable for processing channels with a transmission bandwidth of less than 64 kbit/s. The remote unit 300 is located several kilometers from the switching office 52 and is set up directly in or at the switching office 304 . The connecting line 302 corresponds essentially to the connecting line 66 so that there are transmission channels with a transmission rate of, for example, 16 kbit/s on the connecting line 302 as well.
The switching office 52 has already been explained above with reference to FIG. 2 in terms of its design. The subscriber line module 56 and the compression unit 132 were explained above with reference to FIG. 3 . In the exemplary embodiment according to FIG. 6 , the switching office 52 contains a PCM interface 306 to which the end of the connecting line 302 , leading to the switching office 52 , is connected. The PCM interface 306 switches basic channels with a transmission bandwidth of 64 kbit/s and is connected to the main switching matrix 70 via a line 308 . Each basic channel contains four user information channels. Compressed user information data is transmitted on the line 308 from the main switching matrix 70 to the PCM interface 306 .
Instead of the connecting line 66 , in the exemplary embodiment according to FIG. 6 , a connecting line 310 which leads from the connection unit 100 to a directly adjacent connection unit of the subscriber line module 56 is connected to the subscriber line module 56 . Via the connecting line 310 , the user information data coming from the connection unit 100 passes in compressed form up to the connecting line 308 via the group switching matrix 106 , a transmission link 312 and a transmission channel 314 switched in the switching matrix 70 .
The remote unit 300 contains a PCM interface 316 which is connected to the end, leading to the remote unit 300 , of the connecting line 302 . In addition, the remote unit 300 contains a subscriber line module 318 whose design corresponds essentially to the design of the subscriber line module 206 explained above with reference to FIG. 5 . An adaptation unit 320 fulfills the function of the adaptation unit 226 . The subscriber line module 318 generally contains a compression unit/decompression unit. In the exemplary embodiment according to FIG. 6 , this unit is however not used. A connecting line 322 connects the PCM interface 300 to the subscriber line module 318 . A connecting line 326 several meters long connecting line lies between the subscriber line module 318 and a subscriber line module 324 . The subscriber line module 324 is a conventional subscriber line module in the switching office 304 . In addition to a main switching matrix 328 , a further subscriber line module 330 of the switching office 304 is also illustrated in FIG. 6 . The subscriber line module 330 is connected to the connecting line 210 which leads to the switching office 200 .
A control channel 332 leads from the switching office 52 via the connecting line 302 up to the subscriber line module 318 . Using the control channel 332 , the channels on which user information data is transmitted with a reduced bandwidth can be characterized in the subscriber line module 318 . Data passes in user information channels with a transmission rate of 16 kbit/s via the connecting line 302 to the PCM interface 316 and from there to the adaptation unit 320 , also with a transmission rate of 16 kbit/s. In the adaptation unit 320 , the user information data items of various user information channels are separated from one another and replaced by stop data so that the further transmission via the connecting line 326 to the subscriber line module 324 can take place with a transmission rate of 64 kbit/s per user information channel. If appropriate, the user information data is handled by the partner method which is available in the compression unit, as a result of which a bandwidth of 64 kbit/s is also produced. In the switching office 304 , decompressed user information data is switched, or user information data is switched together with the stop data, and said data passes via the connecting line 210 to the switching office 200 and from there to the switching office 202 . The method steps explained above with reference to FIG. 4 are executed in the switching office 202 .
Signaling of the type of compression in the switching office 52 is maintained, as also explained above with reference to FIG. 4 , cf. arrows 225 , 228 and 232 . | The invention relates to a method for transmitting data having a reduced bandwidth wherein the amount of data intended for transfer over a data transfer network is reduced by a reduction method, wherein the type of reduction performed is signaled by a source switching device to a terminal switching device in the data transfer network, such that in the terminal switching device, transferred data is processed using a partner method to the reduction method in order to recover the original data. | 7 |
RELATED APPLICATIONS
[0001] This application is a continuation-in-part of U.S. patent application Ser. No. 13/752,056 filed Jan. 28, 2013, and this application is also a continuation-in-p art of International PCT Application Serial No. PCT/US2013/028555 filed Mar. 1, 2013, which designates the United States and claims benefit of priority to U.S. Provisional Application Ser. No. 61/605,714, filed Mar. 1, 2012, all of which applications are hereby incorporated by reference in their entirety.
BACKGROUND
[0002] Carbonless paper was developed in the 1950's (NCR) to satisfy the need of being able to produce a duplicate image of an original document. The image is developed when pressure is applied to an original top surface. The pressure generated by the tip of a pen crushes capsules containing a leuco dye releasing the dye which is in solution in one of a number of potential solvents. The dye solution then can react with an unencapsulated developer chemical such as an acidified clay or phenolic compound. The dye becomes protonated and develops a permanent color. Various patents have been granted for microencapsulation processes and coating processes to manufacture carbonless paper. The extent of the use of carbonless paper has been for producing duplicates of original documents.
[0003] Pressure-rupturable microcapsules may be formed in any suitable manner. For example, capsules formed from coacervation of gelatin, polycondensation of urea-formaldehyde, interfacial cross-linking, or hydrolysis of isoclyanatoamidine products may be used. The microencapsulation technology is shown generally, by way of example, in U.S. Pat. No. 4,317,743 issued to Chang et al., U.S. Pat. No. 6,620,571 issued to Katampe et al., as well as U. S. Pat. No. 6,162,485 issued to Chang, all of which are incorporated by reference to the same extent as though fully replicated herein.
[0004] Activities for children may include drawing by various means including crayons, water colors, or finger painting. While the children certainly enjoy these activities, this can necessitate the use of special precautions to prevent the children from making an undue mess. For example, the activities may be limited to a special area and frequently also close caregiver supervision is required.
[0005] Chemicals that change color over a range of temperatures are known as thermochromic systems. Thermochromic chemicals can be manufactured to have a color change that is reversible or irreversible. U.S. Pat. No. 5,591,255, entitled “Thermochromic Ink Formulations, Nail Lacquer and Methods of Use”, issued Jan. 7, 1997 to Small et al., discloses methods of producing thermochromic coating formulations without ingredients known to be harmful to thermochromic inks. The use of distilled water as a fountain solution for off-set printing using thermochromic ink is also disclosed.
[0006] Thermochromic systems use colorants that are either liquid crystals or leuco dyes. Liquid crystals are used less frequently than leuco dyes because they are very difficult to work with and require highly specialized printing and handling techniques. Thermochromic pigments are a system of interacting parts. Leuco dyes act as colorants, while weak organic acids act as color developers. Solvents or waxes variably interact with the leuco dyes according to the temperature of the system. As is known in the art, thermochromic systems are microencapsulated in a protective coating to protect the contents from undesired effects from the environment. Each microcapsule is self-contained, having all of the components of the entire system that are required for the color change. The components of the system interact with one another differently at different temperatures. Generally, the system is ordered and colored below a temperature corresponding to the full color point. The system becomes increasingly unordered and starts to lose its color at a temperature corresponding to an activation temperature.
[0007] Below the activation temperature, the system is usually colored. Above the activation temperature the system is usually clear or lightly colored. The activation temperature corresponds to a range of temperatures at which the transition is taking place between the full color point and the clearing point. Generally, the activation temperature is the temperature at which the human eye can perceive that the system is starting to lose color, or alternatively, starting to gain color. Presently, thermochromic systems are designed to have activation temperatures over a broad range, from about −20° C. to about 80° C. or more. With heating, the system becomes increasingly unordered and continues to lose color until it reaches a level of disorder at a temperature corresponding to a clearing point. At the clearing point, the system lacks any recognizable color.
[0008] In this manner, thermochromic pigments change from a specific color to clear upon the application of thermal energy or heat in a thermally-driven cycle exhibiting well-known hysteresis behavior. Thermochromic pigments come in a variety of colors. When applied to a substrate, such as paper, the pigment exhibits the color of the dye at the core of the microcapsules. In one example, when heat is applied generally in the range of 30 to 32° C., the ink changes from the color of the pigment to clear. When the substrate is allowed to return to a temperature under approximately 30° C., the ink returns to the original color of the pigment.
[0009] U.S. Pat. No. 5,785,746, entitled “Preparation Method for Shear-Thinning Water-Based Ball-Point Pen Inks Compositions and Ball-Point Pens Employing the Same,” issued Jul. 28, 1998 to Kito et al., discloses reversible thermochromic microcapsular pigment mixed in an ink composition. The microcapsules have concavities to moderate stress resulting from an external force during use in a ball-point pen.
[0010] U.S. Pat. No. 5,805,245, entitled “Multilayered Dispersed Thermochromic Liquid Crystal,” issued Sep. 8, 1998 to Davis, discloses a thermochromic substance, applied to inert films in stacked layers with a non-invasive barrier between each thermochromic substance. The thermochromic substance in each layer responds in a different temperature range so that as the temperature changes, each layer repeats a similar sequence of colors. The substrate is a water-based acrylic copolymer formulation coated or permeated with a black pigment. A transparent inert film or non-invasive barrier serves as a protective coating for the thermochromic film and as a support for the next layer of the thermochromic substance.
[0011] Specific thermochromic coating formulations are known in the art. See, for example, U.S. Pat. Nos. 4,720,301, 5,219,625 5,558,700, 5,591,255, 5,997,849, 6,139,779, 6,494,950 and 7,494,537, all of which are expressly incorporated herein by reference. These thermochromic coatings are known to use various components in their formulations, and are generally reversible in their color change. Thermochromic; pigments for use in these coatings are commercially available in various colors, with various activation temperatures, clearing points and full color points. Thermochromic coatings may be printed by offset litho, dry offset, letterpress, gravure, flexo and screen processes, among other techniques.
SUMMARY
[0012] The presently disclosed instrumentalities advance the art by providing a roll of adhesive tape that contains microencapulated pigment intermixed with one or more layers. This may be used to facilitate painting operations where a thermochromic color change confirms that the tape is well adhered for masking purposes. Alternatively, the tape may be constructed so that heat or pressure may be used to draw a design on select areas of the tape.
[0013] According to one embodiment, an elongate substrate is formed in a roll. The substrate may be, for example, crepe paper or plastic that presents a first face and a second face remote from the first face. An adhesive layer covers the first face of the substrate. A microencapsulated pigment is intermixed with at least one member of the group consisting of the adhesive layer, a first coating bonded directly to the first face of the substrate and which is interposed between the substrate and the adhesive layer; and a second coating bonded directly to the second face of the substrate. The microencapsulated pigment is responsive to at least one of temperature and pressure to provide a marking that is visible from a perspective encompassing the second face of the substrate.
[0014] In one aspect, the roll of tape may be such that the microencapsulated pigment may be made of frangible capsules as a mixture of different microcapsules respectively incorporating a leuco dye and a developer. The microencapsulated thermochromic pigment responds to pressure that ruptures the microcapsules to provide a pressure-chromic color change by rupturing the capsules. This type of color change is permanent or irreversible.
[0015] In one aspect, the roll of tape may be such that the microencapsulated pigment may be made of capsules that incorporate a leuco dye system with thermochromic functionality. This microencapsulated pigment responds to temperature to provide a thermochromic color change by rupturing the capsules. This type of color change may be reversible upon cooling of the tape, for example, by refrigeration or by the applicant of ice.
[0016] Specific applications include adhesive tape that permanently changes color as it is pressed into position, for example, where the color change confirms to a painter that masking tape is actually adhering to an intended position. Another example is interactive decorative use where schoolchildren place adhesive tape or film on a desk or textbook and ‘finger paint’ designs.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 shows a substrate that supports one or more layers that contain a mixture of microencapsulated components of a leuco dye system where these components are released for a color-producing interaction upon rupture of the microcapsule walls.
[0018] FIG. 2 shows an image that may be produced by the rupturing of frangible microcapsule walls.
[0019] FIG. 3 shows masking tape where the rupture of frangible microcapsule walls produces a color change which assures the tape is adhering well for use in the painting of a wall or floor.
[0020] FIGS. 4A , 4 B and 4 C show a roll of tape wherein the roll of FIG. 4A is unmarked, that of FIG. 4B carries a permanent or non-reversible marking, and that of FIG. 4C carries a temporary or nonreversible marking.
[0021] FIG. 5 shows a thermochromic hysteresis curve for a red pigment.
[0022] FIG. 6 shows a thermochromic hysteresis curve for a green pigment.
[0023] FIG. 7 shows a thermochromic hysteresis curve for a blue pigment.
DETAILED DESCRIPTION
[0024] In accordance with the instrumentalities described herein, microcapsules containing amine-formaldehyde shell walls are prepared by emulsifying an oily material internal phase in an aqueous medium, and subsequently forming amine-formaldehyde walls around the internal phase by in situ polycondensation. A hydrophilic polymer is optionally added to at least one of the internal phase or the continuous aqueous phase. The hydrophilic polymer becomes incorporated into the microcapsule wall. The hydrophilic polymer may be pectin (methylated polygalacturonic acid) or a synthetic hydrophilic polymer, such as a chemically modified gelatin. The hydrophilic polymer may be suitably added to the internal phase in an amount ranging from 0.01 to 10% by weight and more typically about 0.15 to 3% based on the monomer and also dependent on the color of the resultant batch.
[0025] The hydrophilic polymer is alternatively added to the continuous aqueous phase. The hydrophilic polymer can be dissolved in the continuous aqueous phase where it functions as a viscosity modifier and wall component. Incorporating the hydrophilic polymer into the continuous aqueous phase provides a process for increased control over the size of the resultant microcapsules. The increased aqueous phase viscosity leads to smaller size average capsules. The hydrophilic polymer also plasticizes the microcapsule wall thereby providing better stability and control of the dye release mechanism. The amount of hydrophilic polymer added to the continuous aqueous phase varies with the nature of the hydrophilic polymer and the nature and amount of the other materials used in the composition. The amount is limited to an amount that does not interfere with capsule rupture and reaction of the color former with the developer. The hydrophilic polymer is preferably incorporated in the aqueous phase in an amount of about 0.01 to 10% by weight based on monomer used in the composition and more typically in an amount of 0.15 to 3%.
[0026] Useful hydrophilic polymers include synthetic and natural hydrophilic polymers. Representative examples of such hydrophilic polymers include gum arabic, gelatin, gelatin derivatives such as phthalated gelatins, cellulose derivatives such as hydroxy cellulose, carboxymethyl cellulose and the like, soluble starches such as dextrin and combinations thereof. A preferred class of hydrophilic polymers is chemically modified gelatin. Specific examples of chemically modified gelatins include Gelita™ polymers from Kind & Knox and, more particularly, Gelita™ 8104, 8105, 8106 and 8107. These polymers are modified from Type A or Type B gelatin.
[0027] In capsule manufacture, as aqueous phase serves as the continuous phase of an oil-in-water emulsion in which the oily core materials phase is dispersed. The aqueous phase includes agents known as emulsifiers and system modifiers to control the size and uniformity of the microcapsules and to produce individual mononuclear capsules in preference to clusters of microcapsules. Useful emulsifiers and system modifiers are well known in the art. Their selection will depend on the type of microencapsulation process used and the nature of the wall formers. For making melamine-formaldehyde microcapsules a combination of methylated polygalacturonic acid and sulfonated polystyrenes may be used. The polygalacturonic acid acts as both a stabilizer and a viscosity modifier for the aqueous phase, and the sulfonated polystyrenes aid in emulsification.
[0028] Typical examples of useful sulfonated polystyrenes are Versa TL500 and Versa TL503, products of National Starch Co. Useful sulfonated polystyrenes are generally characterized by a sulfonation degree of over 85% and preferably over 95%. The molecular weight of the sulfonated polystyrene is preferably greater than 100,000 and more preferably about 500,000-1,000,000 but other molecular weights can also be used. The sulfonated polystyrene is usually added to the aqueous phase in an amount of about 1 to 6% by weight. The quality of this product has also been found to vary with the method by which it is manufactured such that certain sulfonated polystyrenes are better than others.
[0029] Dye capsules and developer capsules are manufactured separately and subsequently combined as a mixture. The mixture preferably contains a ratio of dye:developer capsules ranging from 1:1 to 1:20 by weight to achieve a pressure sensitive coating of desirable color with minimal residual color. The following examples teach by way of example and not by limitation.
EXAMPLE 1
[0030] Microencapsulation with Gelatin in the Oil Phase
[0031] 1. Into a stainless steel beaker, 110 g water and 4.6 g dry sodium salt of polyvinylbenzenesulfonic acid (VERSA) are weighed.
[0032] 2. The beaker is clamped in place on a hot plate under an overhead mixer. A six-bladed, 45° pitch, turbine impeller is used on the mixer.
[0033] 3. After thoroughly mixing, 4.0 g pectin (polygalacturonic acid methyl ester) is slowly sifted into the beaker. This mixture is stirred for 2 hours at room temperature (800-1200 rpm).
[0034] 4. The pH is adjusted to 6.0 with 2% sodium hydroxide.
[0035] 5. The mixer is turned up to 3000 rpm and the internal phase is added over a period of 10-15 seconds. Emulsification is continued for 10 minutes at a temperature of 25°-30° C.
[0036] 6. After 20 minutes, the mixing speed is reduced to 2000 rpm, and a solution of melamine-formaldehyde prepolymer is slowly added. This prepolymer is prepared by adding 6.5 g formaldehyde solution (37%) to a dispersion of 3.9 g melamine in 44 g water. After stirring at room temperature for 1 hour the pH is adjusted to 8.5 with 5% sodium carbonate and then heated to 62° C. until the solution becomes clear (30 minutes).
[0037] 7. At the start of emulsification, the hot plate is turned up so heating continues during emulsification.
[0038] 8. The pH is adjusted to 6.0, using 5% phosphoric acid. The beaker is then covered with foil and placed in a water bath to bring the temperature of the preparation to 75° C. When 75° C. is reached, the hot plate is adjusted to maintain this temperature for a two hour cure time during which the capsule walls are formed.
[0039] 9. After curing, mixing speed is reduced to 1800 rpm, formaldehyde scavenger solution (7.7 g urea and 7.0 g water) is added and the solution cured another 40 minutes.
[0040] 10. After 40 minutes hold time, turn down the mixer rpm to 1100 and adjust the pH to 9.5 using a 20% NaOH solution and then allow to stir at 500 rpm overnight at room temperature.
[0041] The materials forming the internal phase are added in step 5 above, and the materials forming the aqueous phase are added in step 6. The total capsule weight preferably comprises from 5% to 30% of a melamine formaldehyde polymer, or another polymer known to the art that is suitable for microencapsulation. Melamine resin Cas#9003-08-1 is particularly preferred. The remainder of the capsule constituting 70% to 95% of the capsule weight is the internal phase where the internal phase is formulated either for use as a dye capsule or as a developer capsule. Any system of a leuco dye and developer may be used.
Dye Capsule:
[0042]
[0000]
Core Material
Wt %
Blue Dye
Cas# 69898-40-4
1-20%
Hexamoll Dinch
Cas# 166412-78-8
80-99%
Developer Capsule:
[0043]
[0000]
Core Material
Wt %
4,4-Biphenol
Cas# 92-88-6
1-25%
Isopropyl myristate
Cas# 110-27-0
75-99%
Dye Capsule:
[0044]
[0000]
Core Material
Wt %
Green Dye
Cas# 34372-72-0
1-20%
Dioctyl phthalate
Cas# 117-84-0
80-99%
Developer Capsule:
[0045]
[0000]
Core Material
Wt %
4,4-Biphenol
Cas# 92-88-6
1-25%
Diiso nonylphalate
2855-12-0
75-99%
EXAMPLE 2
[0046] Microencapsulation with Gelatin in the Aqueous Phase
Model Laboratory Capsule Preparation
[0047] 1. Into a stainless steel beaker, 110 g water and 4.6 g dry sodium salt of polyvinylbenzenesulfonic acid (VERSA) are weighed.
[0048] 2. The beaker is clamped in place on a hot plate under an overhead mixer. A six-bladed, 45° pitch, turbine impeller is used on the mixer.
[0049] 3. After thoroughly mixing, 4.0 g pectin (polygalacturonic acid methyl ester) is slowly sifted into the beaker.
[0050] 4. 0.25-5.0 g gelatin (pellets or solution thereof) is added to the beaker containing pectin/versa with continuous stirring. This mixture is stirred for 2 hours at room temperature (800-1200 rpm).
[0051] 5. The pH is adjusted to 6.0 with 2% sodium hydroxide.
[0052] 6. The mixer is turned up to 3000 rpm and the internal phase is added over a period of 10-15 seconds. Emulsification is continued for 10 minutes at from 25°-30° C.
[0053] 7. At the start of emulsification, the hot plate is turned up so heating continues during emulsification.
[0054] 8. After 20 minutes, the mixing speed is reduced to 2000 rpm, and a solution of melamine-formaldehyde prepolymer is slowly added. This prepolymer is prepared by adding 6.5 g formaldehyde solution (37%) to a dispersion of 3.9 g melamine in 44 g water. After stirring at room temperature for 1 hour the pH is adjusted to 8.5 with 5% sodium carbonate and then heated to 62° C. until the solution becomes clear (30 minutes).
[0055] 9. The pH is adjusted to 6.0, using 5% phosphoric acid. The beaker is then covered with foil and placed in a water bath to bring the temperature of the preparation to 75° C. When 75° C. is reached, the hot plate is adjusted to maintain this temperature for a two hour cure time during which the capsule walls are formed.
[0056] 10. After curing, mixing speed is reduced to 1800 rpm, formaldehyde scavenger solution (7.7 g urea and 7.0 g water) is added and the solution cured another 40 minutes.
[0057] 11. After 40 minutes hold time, turn down the mixer rpm to 1100 and adjust the pH to 9.5 using a 20% NaOH solution and then allow to stir at 500 rpm overnight at room temperature.
[0058] The materials forming the internal phase are added in step 6 above, and the materials forming the aqueous phase are added in step 7. The total capsule weight preferably comprises from 5% to 30% of a melamine formaldehyde polymer, or another polymer known to the art that is suitable for microencapsulation. Melamine resin Cas# 9003-08-1 is particularly preferred. The remainder of the capsule constituting 70% to 95% of the capsule weight is the internal phase where the internal phase is formulated either for use as a dye capsule or as a developer capsule. Any system of a leuco dye and developer may be used.
Dye Capsule:
[0059]
[0000]
Core Material
Wt %
Blue Dye
Cas# 69898-40-4
1-20%
Hexamoll Dinch
Cas# 166412-78-8
80-99%
Developer Capsule:
[0060]
[0000]
Core Material
Wt %
4,4-Biphenol
Cas# 92-88-6
1-25%
Isopropyl myristate
Cas# 110-27-0
75-99%
Dye Capsule:
[0061]
[0000]
Core Material
Wt %
Green Dye
Cas# 34372-72-0
1-20%
Dioctyl phthalate
Cas# 117-84-0
80-99%
Developer Capsule:
[0062]
[0000]
Core Material
Wt %
4,4-Biphenol
Cas# 92-88-6
1-25%
Diiso nonylphalate
2855-12-0
75-99%
[0063] A typical coating composition using the microcapsules described above can be coated onto a substrate, such as Mylar or another plastic. Use on paper or plastic used in the manufacture of adhesive tape is particularly preferred.
[0000]
Ingredient
Wt (g)
Wt %%
Microcapsules
4.94 g
29%
Phenolic Resin (HRJ 4542 from
11.54 g
68%
Schenectady Chemical Co.)
Polyvinyl alcohol (airvol grade 205
0.26 g
1.5%
from Air Products Co.)
Sequrez 755 (binder)
0.26 g
1.5%
[0064] FIG. 1 shows a sheet material 100 that is provided with one or more coatings made from a mixture of frangible microcapsules as described above. A substrate 102 may be, for example, a flexible plastic or cellulosic sheet. A variety of options exist for applied coatings that contain a mixture of microcapsules. The microcapsules may be mixed into a liquid material and applied as layer 104 at the bottom of substrate 102 . The layer 104 may be applied as a liquid that is then dried or cured to form a solid or gel material. An adhesive layer 106 is optionally included if it is desirable for the substrate 102 to adhere to other surfaces. If this is the case, then the layer 104 is optionally eliminated, as a commercially available adhesive may be modified by addition of the mixture of microcapsules such that color-forming occurs within the adhesive layer 106 . Layer 108 is optionally included or eliminated, and may be a layer like layer 104 , except one top-coating the substrate 102 .
[0065] It will be appreciated that any system of commercially available leuco dye and developer materials may be used to produce pigments as described above in a range of colors. Color options include blue, red, green, black, magenta, orange, aqua, yellow, purple, etc. Color to color options may be green color that develops on yellow, purple color that develops on pink, red color that develops on yellow, etc.
[0066] A force 110 may be applied to top surface 112 for purposes of rupturing the frangible microcapsules. The force 110 may be applied manually using fingers or manually manipulated tools, such as a spatula or other implement. Where this occurs locally, by way of example, it is possible to drawn an image 200 , as shown in FIG. 2 , where the substrate 102 is a flexible sheet of plastic or cellulosic material. Where the substrate 102 is a masking tape 300 as shown in FIG. 3 , the tape may be deployed at the intersection between a wall 302 and a floor 304 . A color-developed area 306 indicates that the tape has been pressed sufficiently for adherence to the underlying floor 304 or wall 302 , and an undeveloped area 308 indicates that the tape has been positioned but adherence is insufficient because the lack of developed color indicates the tape has not been pressed against the underlying floor 304 or wall 302 .
[0067] As shown in FIG. 4A , a roll of tape 400 that is prepared as described above may be unrolled to present an unmarked face 402 . FIG. 4B shows roll 404 presenting a face 406 that has been marked by the use of pressure sufficient to create a design constituting the words “sign here.” This marking on face 406 is permanent or non-reversible due to the frangible nature of the microcapsules in layers 104 , 106 or 108 (shown in FIG. 1 ).
[0068] In an alternative embodiment of FIG. 4C , roll 408 presents a face 410 with a design, here shown as a cross-hatch design, that is nonpermanent or reversible due to the use of different microcapsules in layers 104 , 106 , 108 .
[0069] FIGS. 5-7 show, by way of example, the thermochromic hysteresis behavior of thermochromic pigments that are formulated for use as described above. Taken altogether, FIGS. 5-7 show that thermochromic pigments with different thermal response profiles may be used in combination to provide variations in color that may differ depending upon the speed at which a heated object traverses surface 410 (see FIG. 4C ).
[0070] FIG. 5 indicates a red pigment response having a color activation along the cooling curve from 20° C. to 16.5° C., with full color development 500 at 16.5° C. The developed color stays red along the warming cycle until color deactivation commences 502 at 29° C. and the color is fully deactivated 504 at 32° C.
[0071] FIG. 6 indicates a green pigment response having a color activation along the cooling curve from 17° C. to 15° C., with full color development 600 at 17° C. The developed color stays green along the warming cycle until color deactivation commences 602 at 26° C. and the color is fully deactivated 604 at 28° C.
[0072] FIG. 7 indicates a blue pigment response having a color activation along the cooling curve from 14° C. to 12° C., with full color development 700 at 12° C. The developed color stays blue along the warming cycle until color deactivation commences 702 at about 24° C. and the color is fully deactivated 704 at 26° C.
[0073] Liquid coating materials for use in forming layers 104 , 106 , 108 may be purchased on commercial order from Chromatic Technologies, Inc. of Colorado Springs, Colo. The color and thermal hysteresis behavior may be adjusted by design using the principles described below.
[0074] Thermochromic coatings useful in the layers 104 , 106 , 108 contain microcapsules, which encapsulate a thermochromic system mixed with a solvent. The thermochromic system has a material property of a thermally conditional hysteresis window that presents a thermal separation. These coatings may be improved according to the instrumentalities described herein by using a co-solvent that is combined with the thermochromic system. The thermochromic system may contain, for example, at least one chromatic organic compound and co-solvents.
[0075] One example of a thermochromic system includes a leuco dye having a lactone ring structure and a phenolic developer. Within the encapsulated thermochromic systems, complexes form between the dye and the weak acid developer that allow the lactone ring structure of the leuco dye to be opened. The nature of the complex is such that the hydroxyl groups of the phenolic developer interact with the open lactone ring structure forming a supra-molecular structure that orders the dyes and developers such that a color is formed. Color forms from this supra-molecular structure because the dye molecule in the ring open structure is cationic in nature and the molecule has extended conjugation allowing absorption in the visible spectrum thus producing a colored species. The color that is perceived by the eye is what visible light is not absorbed by the complex. The nature of the dye/developer complex depends on the molar ratio of dye and developer. The stability of the colored complex is determined by the affinity of the solvent for itself, the developer or the dye/developer complex. In a solid state, below the full color point, the dye/developer complex is stable. In the molten state, the solvent destabilizes the dye/developer complex and the equilibrium is more favorably shifted towards a developer/solvent complex. This happens at temperatures above the full color point because the dye/developer complex is disrupted and the extended conjugation of the π cloud electrons that allow for the absorption of visible light are destroyed.
[0076] The melting and crystallization profile of the solvent system determines the nature of the thermochromic system. The full color point of the system occurs when the maximum amount of dye is developed. In a crystallized solvent state, the dye/developer complex is favored where the dye and developer exist in a unique crystallized structure, often intercalating with one another to create an extended conjugated π system. In the molten state, the solvent(s), in excess, have enough kinetic energy to disrupt the stability of the dye/developer complex, and the thermochromic system becomes decolorized.
[0077] The addition of a co-solvent with a significantly higher melting point than the other dramatically changes the melting properties of both the solvents. By mixing two solvents that have certain properties, a blend can be achieved that possesses a eutectic melting point. The melting point of a eutectic blend is lower than the melting point of either of the co-solvents alone and the melting point is sharper, occurring over a smaller range of temperatures. The degree of the destabilization of the dye/developer complex can be determined by the choice of solvents. By creating unique eutectic blends, both the clearing point and the full color point can be altered simultaneously. The degree of hysteresis is then shifted in both directions simultaneously as the sharpness of the melting point is increased.
[0078] Temperature changes in thermochromic systems are associated with color changes. If this change is plotted on a graph having axes of temperature and color, the curves do not align and are offset between the heating cycle and the cooling cycle. The entire color versus temperature curve has the form of a loop. Such a result shows that the color of a thermochromic system does not depend only on temperature, but also on the thermal history, i.e. whether the particular color was reached during heating or during cooling. This phenomenon is generally referred to as a hysteresis cycle and specifically referred to herein as color hysteresis or the hysteresis window. Decreasing the width of this hysteresis window to approximately zero would allow for a single value for the full color point and a single value for the clearing point. This would allow for a reliable color transition to be observed regardless of whether the system is being heated or cooled. Nonetheless, the concept decreasing separation across the hysteresis window is elusive in practice. Thus, it is an object of the present disclosure to provide thermochromic systems with a reduced hysteresis window achieved by shifting both the full color point and the clearing point or color deactivation temperature, for example.
Leuco Dyes
[0079] Leuco dyes most commonly used as color formers in thermochromic systems of the present disclosure include, but are not limited to, generally; spirolactones, fluorans, spiropyrans, and fulgides; and more specifically; diphenylmethane phthalide derivatives, phenylindolylphthalide derivatives, indolylphthalide derivatives, diphenylmethane azaphthalide derivatives, phenylindolylazaphthalide derivatives, fluoran derivatives, styrynoquinoline derivatives, and diaza-rhodamine lactone derivatives which can include: 3,3-bis(p-dimethylaminophenyl)-6-dimethylaminophthalide; 3-(4-diethylaminophenyl)-3-(1-ethyl-2-methylindol-3-yl) phthalide; 3,3-bis(1-n-butyl-2-methylindol-3-yl)phthalide; 3,3-bis(2-ethoxy-4-diethylaminophenyl)-4-azaphthalide; 3-[2-ethoxy-4-(N-ethylanilino)phenyl[-3-(1-ethyl-2-methylindol-3-yl)-4-azaphthalide; 3,6-dimethoxyfluoran; 3,6-di-n-butoxyfluoran; 2-methyl-6-(N-ethyl-N-p-tolylamino)fluoran; 3-chloro-6-cyclohexylaminofluoran; 2-methyl-6-cyclohexylaminofluoran; 2-(2-chloroanilino)-6-di-n-butylamino fluoran; 2-(3-trifluoromethylanilino)-6-diethylaminofluoran; 2-(N-methylanilino)-6-(N-ethyl-N-p-tolylamino) fluoran, 1,3-dimethyl-6-diethylaminofluoran; 2-chloro-3-methyl-6-diethylamino fluoran; 2-anilino-3-methyl-6-diethylaminofluoran; 2-anilino-3-methyl-6-di-n-butylamino fluoran; 2-xylidino-3-methyl-6-diethylaminofluoran; 1,2-benzo-6-diethylaminofluoran; 1,2-benzo-6-(N-ethyl-N-isobutylamino)fluoran,1,2-benzo-6-(N-ethyl-N-isoamylamino)fluoran; 2-(3-methoxy-4-dodecoxystyryl)quinoline; spiro[5H-(1) benzopyrano(2,3-d)pyrimidine-5,1′(3′H)isobenzofuran[-3′-one; 2-(diethylamino)-8-(diethylamino)-4-methyl-spiro[5H-(1)benzopyrano(2,3-d)pyrimidine-5,1′(3′H)isobenzofuran[-3′-one; 2-(di-n-butylamino)-8-(di-n-butylamino)-4-methyl-spiro[5H-(1)benzopyrano(2,3-d)pyrimidine-5,1′(3′H)isobenzofuran[-3′-one; 2-(di-n-butylamino)-8-(diethylamino)-4-methyl-spiro[5H-(1)benzopyrano(2,3-d)pyrimidine-5,1′(3′H)isobenzofuran[-3′-one; 2-(di-n-butylamino)-8(N-ethyl-N-isoamylamino)-4-methyl-spiro[5H-(1)benzopyrano(2,3-d)pyrimidine-5,1′(3′H)isobenzofuran[-3′-one; and 2-(di-n-butylamino)-8-(di-n-butylamino)-4-phenyl and trisubstituted pyridines.
Developers
[0080] Weak acids that can be used as color developers act as proton donors, changing the dye molecule between its leuco form and its protonated colored form; stronger acids make the change irreversible. Examples of developers used in the present disclosure include but are not limited to: bisphenol A; bisphenol F; tetrabromobisphenol A; 1′-methylenedi-2-naphthol; 1,1,1-tris(4-hydroxyphenyl)ethane; 1,1-bis(3-cyclohexyl-4-hydroxyphenyl)cyclohexane; 1,1-bis(4-hydroxy-3-methylphenyl)cyclohexane; 1,1-bis(4-hydroxyphenyl)cyclohexane; 1,3-bis[2-(4-hydroxyphenyl)-2-propyl]benzene; 1-naphthol; 2-naphthol; 2,2 bis(2-hydroxy-5-biphenylyl)propane; 2,2-bis(3-cyclohexyl-4-hydroxy)propane; 2,2-bis(3-sec-butyl-4-hydroxyphenyl)propane; 2,2-bis(4-hydroxy-3-isopropylphenyl)propane; 2,2-bis(4-hydroxy-3-methylphenyl)propane; 2,2-bis(4-hydroxyphenyl)propane; 2,3,4-trihydroxydiphenylmethane; 4,4′-(1,3-Dimethylbutylidene)diphenol; 4,4′-(2-Ethylidene)diphenol; 4,4′-(2-hydroxybenzylidene)bis(2,3,6-trimethylphenol); 4,4′-biphenol; 4,4′-dihydroxydiphenyl ether; 4,4′-dihydroxydiphenylmethane; 4,4′-methylidenebis(2-methylphenol); 4-(1,1,3,3-tetramethylbutyl)phenol; 4-phenylphenol; 4-tert-butylphenol; 9,9-bis(4-hydroxyphenyl)fluorine; 4,4′-(ethane-1,1-diyfldiphenol; alpha,alpha′-bis(4-hydroxyphenyl)-1,4-diisopropylbenzene; alpha,alpha,alpha'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene; benzyl 4-hydroxybenzoate; bis(4-hydroxyphenyl)sulfide; bis(4-hydroxyphenyl)sulfone; propyl 4-hydroxybenzoate; methyl 4-hydroxybenzoate; resorcinol; 4-tert-butyl-catechol; 4-tert-butyl-benzoic acid; ,1′-methylenedi-2-naphthol 1,1,1-tris(4-hydroxyphenyl)ethane; 1,1-bis(3-cyclohexyl-4-hydroxyphenyl)cyclohexane; 1,1-bis(4-hydroxy-3-methylphenyl)cyclohexane; 1,1-bis(4-hydroxyphenyl)cyclohexane; 1,3-bis[2-(4-hydroxyphenyl)-2-propyl]benzene; 1-naphthol 2,2′-biphenol; 2,2-bis(2-hydroxy-5-biphenylyl)propane; 2,2-bis(3-cyclohexyl-4-hydroxyphenyl)propane; 2,2-bis(3-sec-butyl-4-hydroxyphenyl)propane; 2,2-bis(4-hydroxy-3-isopropylphenyl)propane; 2,2-bis(4-hydroxy-3-methylphenyl)propane; 2,2-bis(4-hydroxyphenyl)propane; 2,3,4-trihydroxydiphenylmethane; 2-naphthol; 4,4′-(1,3-dimethylbutylidene)diphenol; 4,4′-(2-ethylhexylidene)dipheno14,4′-(2-hydroxybenzylidene)bis(2,3,6-trimethylphenol); 4,4′-biphenol; 4,4′-dihydroxydiphenyl ether; 4,4′-dihydroxydiphenylmethane; 4,4′-ethylidenebisphenol; 4,4′-methylenebis(2-methylphenol); 4-(1,1,3,3-tetramethylbutyl)phenol; 4-phenylphenol; 4-tert-butylphenol; 9,9-bis(4-hydroxyphenyl)fluorine; alpha,alpha'-bis(4-hydroxyphenyl)-1,4-diisopropylbenzene; α,α,α-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene; benzyl 4-hydroxybenzoate; bis(4-hydroxyphenyl) sulfidem; bis(4-hydroxyphenyl) sulfone methyl 4-hydroxybenzoate; resorcinol; tetrabromobisphenol A; 3,5-di-tertbutyl-salicylic acid; zinc 3,5-di-tertbutylsalicylate; 3-phenyl-salicylic acid; 5-tertbutyl-salicylic acid; 5-n-octyl-salicylic acid; 2,2′-biphenol; 4,4′-di-tertbutyl-2,2′-biphenol; 4,4′-di-n-alkyl-2,2′-biphenol; and 4,4′-di-halo-2,2′-biphenol, wherein the halo is chloro, fluoro, bromo, or iodo.
Solvents
[0081] The best solvents to use within the thermochromic system are those that have low reactivity, have a relatively large molecular weight (i.e. over 100), and which are relatively non-polar. Very low molecular weight aldehydes, ketones, diols and aromatic compounds should not be used as solvents within the thermochromic system.
[0082] Thermochromic coatings disclosed herein use a co-solvent that is combined with the thermochromic system. This material may be provided in an effective amount to reduce the thermal separation in the overall coatng to a level less than eighty percent of separation that would otherwise occur if the material were not added. This effective amount may range, for example from the 12% to 15% by weight of the composition.
[0083] The addition of a co-solvent with a significantly higher melting point than the other dramatically changes the melting properties of both the solvents. By mixing two solvents that have certain properties, a blend can be achieved that possesses a eutectic melting point. The melting point of a eutectic blend is lower than the melting point of either of the co-solvents alone and the melting point is sharper, occurring over a smaller range of temperatures. The degree of the destabilization of the dye/developer complex can be determined by the choice of solvents. By creating unique eutectic blends, both the clearing point and the full color point can be altered simultaneously. The degree of hysteresis is then shifted in both directions simultaneously as the sharpness of the melting point is increased. Copending application Ser. No. 13/363,070 filed Jan. 31, 2012 discloses thermochromic systems with controlled hysteresis, and is hereby incorporated by reference to the same extent as though fully replicated herein. According to the instrumentalities described therein, the microencapsulate pigments may be formulated to have color transition temperatures across a hysteresis window of less than five degrees centigrade or more than 60 or 80 degrees centigrade.
[0084] Properties of at least one of the co-solvents used in the present disclosure include having a long fatty tail of between 12 and 24 carbons and possessing a melting point that is about 70° C. to about 200° C. greater than the co-solvent partner. The co-solvents are preferably also completely miscible at any ratio.
[0085] Solvents and/or co-solvents used in thermochromic generally may include, but are not limited to, sulfides, ethers, ketones, esters, alcohols, and acid amides. These solvents can be used alone or in mixtures of 2 or more. Examples of the sulfides include: di-n-octyl sulfide; di-n-nonyl sulfide; di-n-decyl sulfide; di-n-dodecyl sulfide; di-n-tetradecyl sulfide; di-n-hexadecyl sulfide; di-n-octadecyl sulfide; octyl dodecyl sulfide; diphenyl sulfide; dibenzyl sulfide; ditolyl sulfide; diethylphenyl sulfide; dinaphthyl sulfide; 4,4′-dichlorodiphenyl sulfide; and 2,4,5,4′tetrachlorodiphenyl sulfide. Examples of the ethers include: aliphatic ethers having 10 or more carbon atoms, such as dipentyl ether, dihexyl ether, diheptyl ether, dioctyl ether, dinonyl ether, didecyl ether, diundecyl ether, didodecyl ether, ditridecyl ether, ditetradecyl ether, dipentadecyl ether, dihexadecyl ether, dioctadecyl ether, decanediol dimethyl ether, undecanediol dimethyl ether, dodecanediol dimethyl ether, tridecanediol dimethyl ether, decanediol diethyl ether, and undecanediol diethyl ether; alicyclic ethers such as s-trioxane; and aromatic ethers such as phenylether, benzyl phenyl ether, dibenzyl ether, di-p-tolyl ether, 1-methoxynaphthalene, and 3,4,5trimethoxytoluene.
[0086] Examples of ketone solvents include: aliphatic ketones having 10 or more carbon atoms, such as 2-decanone, 3-decanone, 4-decanone, 2-undecanone, 3-undecanone, 4-undecanone, 5-undecanone, 6-undecanone, 2-dodecanone, 3-dodecanone, 4-dodecanone, 5-dodecanone, 2-tridecanone, 3-tridecanone, 2-tetradecanone, 2-pentadecanone, 8-pentadecanone, 2-hexadecanone, 3-hexadecanone, 9-heptadecanone, 2-pentadecanone, 2-octadecanone, 2-nonadecanone, 10-nonadecanone, 2-eicosanone, 11-eicosanone, 2-heneicosanone, 2-docosanone, laurone, and stearone; aryl alkyl ketones having 12 to 24 carbon atoms, such as n-octadecanophenone, n-heptadecanophenone, n-hexadecanophenone, n-pentadecanophenone, n-tetradecanophenone, 4-n-dodecaacetophenone, n-tridecanophenone, 4-n-undecanoacetophenone, n-laurophenone, 4-n-decanoacetophenone, n-undecanophenone, 4-n-nonylacetophenone, n-decanophenone, 4-n-octylacetophenone, n-nonanophenone, 4-n-heptylacetophenone, n-octanophenone, 4-n-hexylacetophenone, 4-n-cyclohexylacetophenone, 4-tert-butylpropiophenone, n-heptaphenone, 4-n-pentylacetophenone, cyclohexyl phenyl ketone, benzyl n-butyl ketone, 4-n-butylacetophenone, n-hexanophenone, 4-isobutylacetophenone, 1-acetonaphthone, 2-acetonaphthone, and cyclopentyl phenyl ketone; aryl aryl ketones such as benzophenone, benzyl phenyl ketone, and dibenzyl ketone; and alicyclic ketones such as cyclooctanone, cyclododecanone, cyclopentadecanone, and 4-tert-butylcyclohexanone, ethyl caprylate, octyl caprylate, stearyl caprylate, myristyl caprate, stearyl caprate, docosyl caprate, 2-ethylhexyl laurate, n-decyl laurate, 3-methylbutyl myristate, cetyl myristate, isopropyl palmitate, neopentyl palmitate, nonyl palmitate, cyclohexyl palmitate, n-butyl stearate, 2-methylbutyl stearate, stearyl behenate 3,5,5-trimethylhexyl stearate, n-undecyl stearate, pentadecyl stearate, stearyl stearate, cyclohexylmethyl stearate, isopropyl behenate, hexyl behenate, lauryl behenate, behenyl behenate, cetyl benzoate, stearyl p-tert-butylbenzoate, dimyristyl phthalate, distearyl phthalate, dimyristyl oxalate, dicetyl oxalate, dicetyl malonate, dilauryl succinate, dilauryl glutarate, diundecyl adipate, dilauryl azelate, di-n-nonyl sebacate, 1,18-dineopentyloctadecylmethylenedicarboxylate, ethylene glycol dimyristate, propylene glycol dilaurate, propylene glycol distearate, hexylene glycol dipalmitate, 1,5-pentanediol dimyristate, 1,2,6-hexanetriol trimyristate, 1,4-cyclohexanediol didecanoate, 1,4-cyclohexanedimethanol dimyristate, xylene glycol dicaprate, and xylene glycol distearate.
[0087] Ester solvents can be selected from esters of a saturated fatty acid with a branched aliphatic alcohol, esters of an unsaturated fatty acid or a saturated fatty acid having one or more branches or substituents with an aliphatic alcohol having one or more branches or 16 or more carbon atoms, cetyl butyrate, stearyl butyrate, and behenyl butyrate including 2-ethylhexyl butyrate, 2-ethylhexyl behenate, 2-ethylhexyl myristate, 2-ethylhexyl caprate, 3,5,5-trimethylhexyl laurate, 3,5,5-trimethylhexyl palmitate, 3,5,5-trimethylhexyl stearate, 2-methylbutyl caproate, 2-methylbutyl caprylate, 2-methylbutyl caprate, 1-ethylpropyl palmitate, 1-ethylpropyl stearate, 1-ethylpropyl behenate, 1-ethylhexyl laurate, 1-ethylhexyl myristate, 1-ethylhexyl palmitate, 2-methylpentyl caproate, 2-methylpentyl caprylate, 2-methylpentyl caprate, 2-methylpentyl laurate, 2-methylbutyl stearate, 2-methylbutyl stearate, 3-methylbutyl stearate, 2-methylheptyl stearate, 2-methylbutyl behenate, 3-methylbutyl behenate, 1-methylheptyl stearate, 1-methylheptyl behenate, 1-ethylpentyl caproate, 1-ethylpentyl palmitate, 1-methylpropyl stearate, 1-methyloctyl stearate, 1-methylhexyl stearate, 1,1dimethylpropyl laurate, 1-methylpentyl caprate, 2-methylhexyl palmitate, 2-methylhexyl stearate, 2-methylhexyl behenate, 3,7-dimethyloctyl laurate, 3,7-dimethyloctyl myristate, 3,7-dimethyloctyl palmitate, 3,7-dimethyloctyl stearate, 3,7-dimethyloctyl behenate, stearyl oleate, behenyl oleate, stearyl linoleate, behenyl linoleate, 3,7-dimethyloctyl erucate, stearyl erucate, isostearyl erucate, cetyl isostearate, stearyl isostearate, 2-methylpentyl 12-hydroxystearate, 2-ethylhexyl 18-bromostearate, isostearyl 2-ketomyristate, 2-ethylhexyl-2-fluoromyristate, cetyl butyrate, stearyl butyrate, and behenyl butyrate.
[0088] Examples of the alcohol solvents include monohydric aliphatic saturated alcohols such as decyl alcohol, undecyl alcohol, dodecyl alcohol, tridecyl alcohol, tetradecyl alcohol, pentadecyl alcohol, hexadecyl alcohol, heptadecyl alcohol, octadecyl alcohol, eicosyl alcohol, behenyl alcohol and docosyl alcohol; aliphatic unsaturated alcohols such as allyl alcohol and oleyl alcohol, alicyclic alcohols such as cyclopentanol, cyclohexanol, cyclooctanol, cyclododecanol, and 4-tert-butylcyclohexanol; aromatic alcohols such as 4-methylbenzyl alcohol and benzhydrol; and polyhydric alcohols such as polyethylene glycol. Examples of the acid amides include acetamide, propionamide, butyramide, capronamide, caprylamide, capric amide, lauramide, myristamide, palmitamide, stearamide, behenamide, oleamide, erucamide, benzamide, capronanilide, caprylanilide, capric anilide, lauranilide, myristanilide, palmitanilide, stearanilide, behenanilide, oleanilide, erucanilide, N-methylcapronamide, N-methylcaprylamide, N-methyl (capric amide), N-methyllauramide, N-methylmyristamide, N-methylpalmitamide, N-methylstearamide, N-methylbehenamide, N-methyloleamide, N-methylerucamide, N-ethyllauramide, N-ethylmyristamide, N-ethylpalmitamide, N-ethylstearamide, N-ethyloleamide, N-butyllauramide, N-butylmyristamide, N-butylpalmitamide, N-butylstearamide, N-butyloleamide, N-octyllauramide, N-octylmyristamide, N-octylpalmitamide, N-octylstearamide, N-octyloleamide, N-dodecyllauramide, N-dodecylmyristamide, N-dodecylpalmitamide, N-dodecylstearamide, N-dodecyloleamide, dilauroylamine, dimyristoylamine, dipalmitoylamine, distearoylamine, dioleoylamine, trilauroylamine, trimyristoylamine, tripalmitoylamine, tristearoylamine, trioleoylamine, succinamide, adipamide, glutaramide, malonamide, azelamide, maleamide, N-methylsuccinamide, N-methyladip amide, N-methylglutaramide, N-methylmalonamide, N-methylazelamide, N-ethylsuccinamide, N-ethyladipamide, N-ethylglutaramide, N-ethylmalonamide, N-ethylazelamide, N-butylsuccinamide, N-butyladipamide, N-butylglutaramide, N-butylmalonamide, N-octyladipamide, and N-dodecyladipamide.
[0089] Among these solvents, it has been discovered that certain solvents have the effect of reducing the hysteresis window. The solvent may be material combined with the thermochromic system, for example, to reduce thermal separation across the hysteresis window to a level demonstrating 80%, 70%, 50%, 40%, 30% or less of the thermal separation that would exist if the co-solvent were not present. The co-solvent is selected from the group consisting of derivatives of mysristic acid, derivatives of behenyl acid, derivatives of palmytic acid and combinations thereof. Generally, these materials include myristates, palmitates, behenates, together with myristyl, stearyl, and behenyl materials and certain alcohols. In one aspect, these materials are preferably solvents and co-solvents from the group including isopropyl myristate, isopropyl palmitate, methyl palmitate, methyl stearate, myristyl myristate, cetyl alcohol, stearyl alcohol, behenyl alcohol, stearyl behenate, and stearamide. These co-solvents are added to the encapsulated thermochromic system in an amount that, for example, ranges from 9% to 18% by weight of the thermochromic system as encapsulated, i.e., excluding the weight of the capsule. This range is more preferably from about 12% to about 15% by weight.
Light Stabilizers
[0090] Thermochromic coatings containing leuco dyes are available for all major coating types such as water-based, ultraviolet cured and epoxy. The properties of these coatings differ from process coatings. For example, most thermochromic coatings contain the thermochromic systems as microcapsules, which are not inert and insoluble as are ordinary process pigments. The size of the microcapsules containing the thermochromic systems ranges typically between 3-5 um which is more than 10-times larger than regular pigment particles found in most coatings. The post-print functionality of thermochromic coatings can be adversely affected by ultraviolet light, temperatures in excess of 140° C. and aggressive solvents. The lifetime of these coatings is sometimes very limited because of the degradation caused by exposure to ultraviolet light from sunlight.
[0091] In other instances, additives used to fortify the encapsulated thermochromic systems by imparting a resistance to degradation by ultraviolet light by have a dual functionality of also reducing the width of separation over the hysteresis window. Light stabilizers are additives which prevent degradation of a product due to exposure to ultraviolet radiation. Examples of light stabilizers used in thermochromic systems of the present disclosure and which may also influence the hysteresis window include but are not limited to: avobenzone, bisdisulizole disodium , diethylaminohydroxybenzoyl hexyl benzoate, Ecamsule, methyl anthranilate, 4-aminobenzoic acid, Cinoxate, ethylhexyl triazone, homosalate, 4-methylbenzylidene camphor, octyl methoxycinnamate, octyl salicylate, Padimate O, phenylbenzimidazole sulfonic acid, polysilicone-15, trolamine salicylate, bemotrizinol, benzophenones 1-12, dioxybenzone, drometrizole trisiloxane, iscotrizinol, octocrylene, oxybenzone, sulisobenzone , bisoctrizole, titanium dioxide and zinc oxide.
[0092] Careful preparation of encapsulated reversible thermochromic material enhances coating stability in the presence of low molecular weight polar solvents that are known to adversely affect thermochromic behavior. One skilled in the art of microencapsulation can utilize well-known processes to enhance the stability of the microcapsule. For example, it is understood that increasing the cross linking density will reduce the permeability of the capsule wall, and so also reduces the deleterious effects of low molecular weight solvents. It is also commonly understood that, under certain conditions, weak acids with a pKa greater than about 2 may catalyze microcapsule wall polymerization and increase the resulting cross linking density. It is presently the case that using formic acid as a catalyst enhances solvent stability of blue thermochromic microcapsules in the presence of low molecular weight ketones, diols, and aldehydes at room temperature. Further, it is well understood that increasing the diameter of the thermochromic microcapsule can result in enhanced solvent stability.
[0093] The selection of material for use as the non-polar solvent for the thermochromic dye and color developer that is encapsulated within the thermochromic pigment determines the temperature at which color change is observed. For example, changing the solvent from a single component to a two component solvent system can shift the temperature at which full color is perceived almost 7° C. from just under 19° C. to 12° C. The present disclosure shows how to apply this knowledge in preparing resin-based vehicle coatings for use in can and coil coatings with full color temperatures, i.e., the temperature at which maximum color intensity is observed, as low as −5° C. and as high as 65° C. No adverse effects on the physical properties of the resulting coating were observed as the full color temperature was changed over the above range by the use of different straight chain alkyl esters, alcohols, ketones or amides.
[0094] Thermochromic materials including encapsulated thermochromic systems with a variety of color properties may be purchased on commercial order from such companies as Chromatic Technologies, Inc., of Colorado Springs, Colo.
[0095] Control over observed color intensity is demonstrated in several ways, generally by providing increased amounts of pigment. For a typical coating, material thickness ranges from 1 mg/in2 to 6 mg/in2. Very intense color is observed for coatings with thickness greater than about 3 mg/in2. Increasing thermochromic pigment solids can also result in a more intense observed color even when coating thickness is decreased. However, dried film properties such as flexibility and toughness may be compromised if too much thermochromic pigment is incorporated. The optimal range of thermochromic pigment solids is within 5 to 40% by weight of the coating.
Encapsulation Process For Non-Frangible Capsules
[0096] Nearly all thermochromic systems require encapsulation for protection. As is known in the art, the most common process for encapsulation is interfacial polymerization. During interfacial polymerization the internal phase (material inside the capsule), external phase (wall material of the capsule) and water are combined through high-speed mixing. By controlling all the temperature, pH, concentrations, and mixing speed precisely, the external phase will surround the internal phase droplet while crosslinking with itself. Usually the capsules are between 3-5 μm or smaller. Such small sizes of capsules are referred to as microcapsules and the thermochromic system within the microcapsules are microencapsulated. Microencapsulation allows thermochromic systems to be used in wide range of materials and products. The size of the microcapsules requires some adjustments to suit particular printing and manufacturing processes.
[0097] The size distribution of microcapsules can range from as much as 0.2 μm to 100 μm. Further example techniques of physical microencapsulation include but are not limited to pan coating, air suspension coating, centrifugal extrusion, vibration nozzle, and spray drying. Examples of chemical microencapsulation techniques include but are not limited to interfacial polymerization, in-situ polymerization, and matrix polymerization. Example polymers used in the preferred chemical microencapsulation include but are not limited to polyester, polyurethane, polyureas, urea-formaldehyde, epoxy, melamine-formaldehyde, polyethylene, polyisocyanates, polystyrene, polyamides, and polysilanes.
[0098] The capsule isolates the thermochromic system from the environment, but the barrier that the capsule provides is itself soluble to certain solvents. Therefore, the microcapsule constituents interact with the environment to some extent. The solubility parameter describes how much a material will swell in the presence of different solvents. This swelling will directly impact the characteristics of the reaction potential within the capsule, as well as potentially making the capsule more permeable, both of which will likely adversely affect the thermochromic system. Solvents in which the microcapsules are exposed to are chosen so as not to destroy, or affect, the thermochromic system within.
[0099] The capsule is hard, thermally stable and relatively impermeable. The infiltration of compounds through the capsule are stopped or slowed to the point that the characteristics of the dye are not affected. The pollution of the thermochromic system within the capsule by solvents from the environment affects the shelf life of the thermochromic system. Therefore, the formulation of the applied thermochromic system, as a coating for example, should be carefully considered.
[0100] In an embodiment of the present disclosure, capsules are made from urea formaldehyde. One technique used to produce the encapsulated thermochromic systems is to combine water, dye, oil, and urea formaldehyde and mix to create a very fine emulsification. Because of the properties of the compounds, the oil and dye end up on the inside of the capsule and the water ends up on the outside, with the urea formaldehyde making up the capsule itself. The capsule can then be thermo-set, similar to other resins, such as formica. The thermo-set substance is very hard and will not break down, even at temperatures higher than the encapsulated thermochromic system is designed to be exposed to. The urea formaldehyde capsule is almost entirely insoluble in most solvents, but it is permeable to certain solvents that might destroy the ability of the thermochromic system to color and decolorize throughout a temperature range.
[0101] The extent to which capsules will react with their environment is influenced by the pH of the surrounding medium, the permeability of the capsule, the polarity and reactivity of compounds in the medium, and the solubility of the capsule. Preferred media used in formulating encapsulated thermochromic system are engineered to reduce the reactivity between that medium and the capsules to a low enough level that the reactivity will not influence the characteristics of the dye for an extended period of time.
[0102] Highly polar solvent molecules, with the exception of water, often interact more with the leuco dye than with the capsule shell and other non-polar molecules of the thermochromic system. Therefore, polar solvents that are able to cross the capsule barrier should, in general, be eliminated from the medium within which the encapsulated thermochromic system is formulated.
[0103] Aqueous media that the encapsulated thermochromic systems are placed within should have a narrow pH range from about 6.5 to about 7.5. When an encapsulated thermochromic system is added to a formulation that has a pH outside this range, often the thermochromic properties of the system are destroyed. This is an irreversible effect.
[0104] One aspect of the present disclosure is for a method of improving the formulations of the thermochromic system by removing any aldehydes, ketones, and diols and replacing them with solvents which do not adversely affect the thermochromic system. Solvents having a large molecular weight (i.e. greater than 100) generally are compatible with the thermochromic systems. The acid content of the system is preferably adjusted to an acid number below 20 or preferably adjusted to be neutral, about 6.5-7.5. Implementing these solvent parameters for use in the thermochromic system will preserve the reversible coloration ability of the leuco dyes.
[0105] Formulations for thermochromic systems are engineered with all the considerations previously mentioned. The examples below describe a thermochromic system with excellent color density, low residual color, narrow temperature ranges between full color and clearing point, and a narrow hysteresis window. The full color point and the clearing point are determined by visual inspection of the thermochromic system at a range of temperatures. The difference in temperature between the maxima of color change during the cooling cycle and the heating cycle is used to calculate hysteresis.
Vehicle
[0106] Physical properties of the finished coating can be significantly affected by the selection of resin to be used. When no resin is used in formulating a reversible thermochromic coating, a matte finish is achieved that is able to be formed into can ends, tabs, caps and/or other closures. While this result may be desired, the inclusion of a low viscosity, relatively low molecular weight resin, monomer, oligomer, polymer, or combination thereof, can enhance gloss and affect other physical film properties such as hardness, flexibility and chemical resistance. The resin is designed to supplement the total solids deposited on the substrate, thus impacting the physical properties of the dried film. Any resin material, monomer, oligomer, polymer, or combination thereof that can be polymerized into the commercially available can and coil coating material is suitable for inclusion in the formulation of the current reversible thermochromic can and coil coating. Acceptable classes of resins include, but are not limited to polyester, urethane, acrylic acid and acrylate, or other types of resin systems with suitably high solids content.
Adjusting the Acid Content
[0107] Water-based coatings are pH adjusted prior to addition of thermochromic pigment. As mentioned above, the pH should be neutral unless observation indicates that a different pH is required. To achieve the correct pH, one uses a good proton donor or acceptor, depending on whether the pH is to be adjusted up or down. To lower the pH, sulfuric acid is used, to raise it, the best proton acceptor so far is KOH. These two chemicals are very effective and do not seem to impart undesirable characteristics to the medium. The most effective pH is about 7.0, however, some tolerance has been noted between 6.0 and 8.0. A pH below 6.0 and above 8.0 has almost always immediately destroyed the pigment.
[0108] The acid value is defined as the number of milligrams of a 0.1 N KOH solution required to neutralize the alkali reactive groups in 1 gram of material under the conditions of ASTM Test Method D-1639-70. It is not yet fully understood how non-aqueous substances containing acid affect the thermochromic, but high acid number substances have inactivated the thermochromic pigments. Generally, the lower the acid number the better. To date coating formulations with an acid value below 20 and not including the harmful solvents described above have worked well. Some higher acid value formulations may be possible but generally it is best to use vehicle ingredients with low acid numbers or to adjust the acid value by adding an alkali substance. The greatest benefit of a neutral or low acid value vehicle will be increased shelf life. Buffers have been used historically in offset coating formulations to minimize the effects of the fountain solution on pigment particles. This is one possible solution to the potential acidity problem of the varnishes. One ingredient often used as a buffer is cream of tartar. A dispersion of cream of tartar and linseed oil can be incorporated into the coating. The net effect is that the pigments in the coating are protected from the acidic fountain solution.
Coating Formulations
[0109] The encapsulated thermochromic systems of the present disclosure may be referred to as pigments. In order to add normal pigment to coating, dye, or lacquer, the pigment itself is ground into the base. This disperses the pigment throughout the base. The addition of more pigment intensifies the color. Since the pigment often has a very intense color, it is sometimes acceptable for only about 10% of the final coating to be made up of normal pigments.
[0110] A base for a coating formulation using encapsulated thermochromic systems of the present disclosure may be developed using off the shelf ingredients. The coating will incorporate, where possible, and be compatible with different coating types and solvents with molecular weights larger than 100 while avoiding aldehydes, diols, ketones, and, in general, aromatic compounds Important considerations with respect to the ingredients within the coating vehicle are the reactivity of the ingredients with the encapsulated thermochromic system.
[0111] Unwanted interactions between media and the encapsulated thermochromic systems can occur between compounds found in coating formulations. The long alkyl chains of many of the compounds found in coating vehicles may have reactive portions that can fit through the pores of the capsule and interact with the inner phase and denature it through this interaction. Since the behavior of the thermochromic system is related to the shape and the location of its molecules at given temperatures, disrupting these structures could have a large impact on the characteristics of the thermochromic system. Even molecules that cannot fit through the capsule pores may have reactive portions that could protrude into the capsule and thereby influence the color transition of the thermochromic system within the capsule. Therefore, mineral spirits, ketones, diols, and aldehydes are preferably minimized in any medium in which the encapsulated are also preferably avoided. If these compounds are substantially reduced or eliminated the thermochromic systems will perform better and have a longer shelf life.
[0112] Another important step in using the encapsulated thermochromic systems of the present disclosure in coating formulations is to adjust the pH or lower the acid value of the coating base before the thermochromic system is added. This can be done by ensuring that each individual component of the base is at the correct pH or acid value or by simply adding a proton donor or proton acceptor to the base itself prior to adding the thermochromic system. The appropriate specific pH is generally neutral, or 7.0. The pH will vary between 6.0 and 8.0 depending on the coating type and the color and batch of the thermochromic system.
[0113] Once a slurry and the base have been properly prepared, they are combined. The method of stirring should be low speed with non-metal stir blades. Other additives may be incorporated to keep the thermochromic system suspended. The coating should be stored at room temperature.
[0114] Most thermochromic pigments undergo a color change from a specific color to colorless. Therefore, layers of background colors can be provided under thermochromic layers that will only be seen when the thermochromic pigment changes to colorless. If an undercoat of yellow is applied to the substrate and then a layer containing blue thermochromic pigment is applied the color will appear to change from green to yellow, when what is really happening is that the blue is changing to colorless.
[0115] The substrates that the thermochromic coatings are printed upon are preferably neutral in pH, and should not impart any chemicals to the capsule that will have a deleterious effect on it.
[0116] Thermochromic coatings contain, in combination, a vehicle and a pigment including thermochromic microcapsules. The thermochromic microcapsules are preferably present in an amount ranging from 1% to 50% of the coating by weight on a sliding scale relative to other pigments. The vehicle contains a solvent that is preferably present in an amount ranging from 25% to 75% by weight of the coating.
[0117] The aqueous pigment slurries have particle sizes less than 5 microns and when drawn-down on coating test paper and dried, the pigment coating shows reversible thermochromic properties when cooled to the solidification point of the fatty ester, alcohol, amide, or a blend designed to obtain a specific temperature for full color formation. Such pigments can be designed to have a range of temperature for transition from full absorption temperature (full absorption color or UVA absorption point) to no color or no UVA absorption temperature (clearing point) of 2-7° C. The pigments are very useful for manufacture of coating, and injected molded plastic products by spray drying prior to formulation into coating compositions or extrusion into thermoplastic polymers to produce pellet concentrates for manufacture of injection molded thermochromic plastic products such as cups, cup lids, jars, straws, stirrers, container sleeves, shrink wrap labels. For example, thermochromic compositions were identified that permit generation of high quality saturated photographic quality yellow color that is very useful to formulate new orange, red, and green colors by mixing with magenta and/or cyan thermochromic pigments or by initial co-encapsulation of the yellow leuco dye with magenta and/or cyan leuco dyes and appropriate color developers during the pigment manufacture. Alternatively leuco pigments were identified that can change from absorption mainly in the region from 280 to 350 nm to absorption mainly from 350 to 400 nm.
EXAMPLE 1
Pigment Formulations
[0118] The internal phase chemistry for the microcapsules has been tested with the following solvents that to engineer the temperature profile and thermal memory:
[0000]
Methyl Palmitate
FC 12-13
CP 23-27
Tetradecanol
FC 17-19
CP 29-33
Lauryl Laurate
FC 15-17
CP 25-29
[0119] These internal phase esters or alcohols have been tested with standard fluoran and phthalide dyes using BHPMP as a chemical developer. The exact temperature profile and thermal memory is specific to the dye, or mixture of dyes. The dyes and developer may be co-encapsulated or separately encapsulated to achieve a specific color with the desired temperature profile and thermal memory. The ratio of the dye:developer may be for example 1:1 to 1:4 in order to achieve desirable color density with minimal residual.
[0120] The following dyes may be microencapsulated with Developer CAS#6807-17-6 (BHPMP) for various color formulations as described above.
[0000]
Aqua dye
CAS# 132467-74-4
Blue-63 dye
CAS# 69898-40-4
Black XV
CAS# 36431-22-8
Red-40 dye
CAS# 50292-91-6
Green dye
CAS# 34372-72-0
Orange dye
CAS# 21934-68-9
[0121] The internal phase as described above may be microencapsulated using conventional urea-formaldehyde processes to form thermochromic pigments.
EXAMPLE 2
Coating Formulations
[0122] Any of the thermochromic pigments prepared according to Example 1 above may be mixed with synthetic resins to form liquid coatings for use as precursors in forming the layers 210 - 218 . Various examples of this chemistry are as follows:
[0123] In one embodiment, a thermochromic coating formulation includes:
[0000]
Ingredient
Weight Percent of Coating
Pigment*
1% to 40%
Vehicle
Polymerizable resin
5% to 30%
Dispersing agent
0% to 5%
Solvent
0% to 50%
Curing agent
0% to 25%
Wax
0% to 5%
*Assessed by solids content upon complete drying of pigment capsules, but does not need to be dried and may be mixed as a slurry.
[0124] In one aspect, a reversible thermochromic coating for use in can and coil coatings contains a reversible thermochromic pigment in an amount from 1% to 50% by weight of the coating, and a vehicle forming the balance of the coating. The vehicle includes a resin selected from the group consisting of epoxy, polyester, urethane, acrylic acid and acrylate resins, and combinations thereof. Commercially available thermochromic pigments may be readily obtained in a variety of colors demonstrating color transition temperatures from about 5° C. and up to about 65° C. A range of color formulations may be made by mixing the pigment to include one or more of the following reversible thermochromic colors: yellow, magenta, cyan, and black. These may be further mixed to include other dyes or solid pigments that are non-thermochromic in nature. The pigment may change from a colorless state to a colored state upon cooling to the reactive temperature, or to a colored state upon heating to the reactive temperature. It is preferred that the microcapsules are formed of urea-formaldehyde or melamine-formaldehyde that is acid catalyzed to enhance the inherent stability in polar, low molecular weight solvents having a molecular weight of about less than 100 g/mol.
[0125] When premised using a nonpolar solvent, the coatings can demonstrate shelf stability exceeding 14 or 45 days when stored at about 20° C. Some coating formulations demonstrate shelf stability in excess of one year.
[0126] The curing agent is generally compatible with the resin for this purpose and may be, for example, a latent blocked amine to initiate a polymerization reaction upon heating.
[0127] The coating is preferably roller-coated onto coil stock aluminum or steel and the roll stock aluminum is subsequently formed into one or more beverage can components. These components may be selected from the group consisting of beverage can ends, beverage can tabs, bottle caps, and/or beverage container closures. The aluminum is preferably an alloy that is commonly used in canning operations, such as aluminum alloy 5182-H48. The coating process preferably occurs in one or more coats to yield a dried film with a thickness ranging from 1 mg/in 2 up to 5.5 mg/in 2 .
EXAMPLE 3
Two Part Coating
[0128] Part A (30% by weight of coating)
[0129] Thermochromic pigment (any color)*
[0130] Part B (70% by weight of coating)
[0131] Clear Coating (an epoxy coating available from Watson Standard of Pittsburgh, Pa.)
[0132] * This material may be purchased on commercial order from Chromatic Technologies, Inc. of Colorado Springs Colo., and may include for example S5BOXX3105W, a blue thermochromic slurry that goes from a colored to colorless state when the temperature exceeds 31° C.
EXAMPLE 4
Two Part Coating
[0133] Part A (60% by weight of coating)
[0134] 45% Thermochromic Pigment (any color)*
[0135] 50% Epoxy resin (for example Epon 863 available from Lawter of LaVergne, Tenn.)
[0136] 3.3% Dispersing aid (for example Disperbyk 2025 available from Byk of Wallingford, Conn.
[0137] 1.7% Curing agent (for example Ancamine 2458 available from Air Products of Allentown, Pa.)
[0138] Part B (40% by weight of coating)
[0139] 85% Clear Coating (an epoxy coating available from Watson Standard of Pittsburgh, Pa.)
[0140] 15% Solvent to reduce viscosity (for example, butyl carbitol acetate available from Lawter of LaVergne, Tenn.)
[0141] * This material may be purchased on commercial order from Chromatic Technologies, Inc. of Colorado Springs Colo., and may include for example S5BOXX3105W, a blue thermochromic slurry that goes from a colored to colorless state when the temperature exceeds 31° C.
EXAMPLE 5
One Part Coating
[0142] 20% (w/w) Thermochromic Pigment (any color)* 13% Polyester resin (for example, Decotherm 290 available from Lawter of LaVergne, Tenn.)
[0143] 0.5% (w/w) Dispersing aid (for example, Byk 370 available from Byk of Wallingford, Conn.)
[0144] 7% (w/w) Curing agent 1 (for example, Cymel 328 available from tec Industries of Woodland Park, N.J.
[0145] 1.5% (w/w) Curing agent 2 (for example, imidazole available from Aldrich of St. Louis, Missouri)
[0146] 2% (w/w) Wax (for example, Fluoron 735 available from Lawter of LaVergne, Tenn.)
[0147] 30% (w/w) Solvent (for example, ethyl-3-ethoxypropionate available from Univar of Redmond, Wash.)
[0148] 26% (w/w) Clear Coating (an epoxy coating available from Watson Standard of Pittsburgh, Pa.)
EXAMPLE 6
One Part Coating
[0149] 15% (w/w) Thermochromic Pigment (any color)*
[0150] 10% (w/w) Resin (for example, Epon 896 available from Lawter of LaVergne, Tenn.)
[0151] 1.5% (w/w) Dispersing aid (for example, Disperbyk 112 available from Byk of Wallingford, Conn.
[0152] 0.5% (w/w) Curing agent 1 (for example, Nacure 2500 available from King Industries of Norwalk, Conn.
[0153] 4% (w/w) Curing agent 2 (for example, Cymel 325 available from Cytec Industries of Woodland Park, N.J.
[0154] 1.5% (w/w) Wax—0.5 wt % (for example, Ultrapoly 211A available from Lawter of LaVergne, Tenn.)
[0155] 5% (w/w) Solvent 1 (for example, Heloxy Modifier 62 available from Lawter of LaVergne, Tenn.)
[0156] 21.5% (w/w) solvent 2 (for example, ethyl-3-ethoxypropionate available from Univar of Redmond, Wash.)
[0157] 41% (w/w) Clear Coating (an epoxy coating available from Watson Standard of Pittsburgh, Pa.)
[0158] Having described the invention in detail and by reference to preferred embodiments thereof, it will be apparent that modifications and variations are possible without departing from the scope of the invention defined in the appended claims. | A microencapsulated pigment including a leuco dye system is incorporated as one or more layers in a roll of adhesive tape. The tape is applied and may be rubbed by hand or another object to induce a color change. The change may serve as an indicator that the tape is well adhered for masking purposes in a painting operation, or to present a design where only selected portions of the tape are rubbed to induce the color change. The microencapsulated pigment may be constructed so that the color change is irreversible or reversible. | 2 |
BACKGROUND OF THE INVENTION
The production of laboratory grade ultrapure water or other fluid reagents often requires contacting the fluid feed with various solid filtration and/or adsorption media to free the water from minute quantities of pollutants such as organic compounds, flocculants and dissolved ionic material. See, for example, U.S. Pat. Nos. 5,868,924 and 5,925,240. There is a need in the art for appropriately designed devices for containing such solid media to maximize efficient contact between the fluid and the media.
BRIEF SUMMARY OF THE INVENTION
The media housing of the present invention consists of top and bottom end caps secured to a dual cartridge media container provided with internal flow conduits and flow distributors and with recesses at the inlet and outlet of each cartridge to accommodate porous discs or screens that act as prefilters and to contain purification media within the cartridges. The inside diameter of each cartridge is such as to accommodate linear cross sectional velocity requirements for ion exchange resin applications, while the overall volume of the dual cartridge is such as to provide sufficient empty bed contact time and depth to satisfy application and design requirements for the use of activated carbons, ion exchange resins, catalysts and other purification and filtration media.
The foregoing and other objectives, features, and advantages of the invention will be more readily understood upon consideration of the following detailed description of the invention, taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
FIG. 1 is a perspective view of the dual cartridge media housing of the present invention.
FIG. 2 is a cross sectional view taken through 2 — 2 of FIG. 1 .
FIG. 3 is an exploded view of FIG. 1 .
FIG. 4 is an elevational view of the outside of the top end cap.
FIG. 5 is an elevational view of the inside of the top end cap.
FIG. 6 is an elevational view of the outside of the bottom end cap.
FIG. 7 is an elevational view of the inside of the bottom end cap.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
An exemplary device of the present invention includes two cartridges molded together as a single piece with a common wall and having two smaller conduits or plenums located adjacent the common wall between the two cartridges. One of the smaller conduits is used for fluid communication between the bottom of the first cartridge and the top of the second cartridge when the end caps are attached. The second smaller conduit is used to allow fluid to flow from the bottom of the second cartridge to the outlet for delivery of permeate or purified fluid from the device.
In an especially preferred embodiment the cartridges are cylindrical and the smaller conduits have a triangular cross sectional shape. The triangular cross sectional shape of these smaller conduits or plenums adds strength to the device while saving space. Advantages of such a dual cartridge design include the minimization of parts and reduction in assembly time. As compared to standard external plumbing typically used to hydraulically connect multiple media containers in similar applications, the internal plumbing of the present invention leads to an efficient use of space.
Turning to the drawings, wherein like numerals refer to the same elements, there is shown a dual cartridge media housing 1 comprising a housing body 10 having a top end cap 12 and a bottom end cap 14 . End caps 12 and 14 are preferably provided with reinforcing ribs 30 . Top end cap 12 is provided with fluid inlet port 18 and permeate outlet port 28 . Top end cap 12 may also be provided with a latch boss 13 and mounting bosses 13 ′ for securing an inlet and outlet nozzle assembly (not shown), said assembly being the subject of copending application Ser. No. 09/733,588, filed concurrently. Housing body 10 and end caps 12 and 14 may be made of any suitable material such as 316 or 316L stainless steel or thermoplastic polymers, preferably the latter and the three components may be secured together by any suitable means; in the case of thermoplastic polymers the three components are preferably welded together. Preferred polymeric materials of construction include polyethylene, polypropylene, polytetrafluoroethylene, polyvinylidene fluoride, fluorinated ethylene/perfluoroalkyl vinyl ether copolymer and polyetheretherketone.
Housing body 12 includes first cartridge 20 and second cartridge 24 bound together by common wall 20 - 24 . Both ends of both first cartridge 20 and second cartridge 24 are fitted with porous screens 16 to act as both a prefilter for large particles and to retain filtration and/or adsorption media/ the screens fitting into screen-receiving recesses 17 countersunk into housing body wall 11 and common wall 20 - 24 . The porous screens in the cartridge pack may be constructed of the same types of material as the cartridge pack.
In operation, fluid to be filtered or otherwise treated with media such as activated carbon or ion exchange media enters fluid inlet port 18 in top end cap 12 , flows downwardly through porous screen 16 and first cartridge 20 , then downwardly through media contained in first cartridge 20 through lower screen 16 , then encounters first cartridge flow collector 21 which directs the first cartridge permeate upwardly through first cartridge permeate plenum 21 to the top of second cartridge 24 . At the top of second cartridge 24 the fluid permeate from the first cartridge encounters second cartridge flow distributor 23 , which causes the flow to be distributed uniformly downwardly through porous screen 16 and the media of second cartridge 24 . At the bottom of second cartridge 24 the permeate flows through screen 16 and encounters second cartridge flow collector 25 which directs the fluid permeate upwardly through second cartridge permeate plenum 26 and out through permeate outlet port 28 .
Fabrication of the housing of the invention is straightforward, comprising placing the two porous screens 16 into the recesses 17 provided inside the end of each cartridge 20 and 24 . The top or bottom end cap 12 or 14 is then secured to the dual cartridges 20 and 24 , preferably by welding. The welding operation captures the porous screens 16 in the welding flash while the end cap 12 or 14 is welded to the dual cartridges. The cartridges are then loaded with fluid filtration/treatment media and the other end cap is secured to the housing body. In general when more than one medium is utilized, the media are placed in the device in discrete layers. One layer of media is normally used to remove a particular contaminant before it reaches a subsequent media layer. For example, activated carbon may be used to remove chlorine and organic contaminants from the fluid feed before it reaches ion exchange resin media to prevent oxidation or fouling. Some media, such as mixed bed ion exchange resins and multimedia material, are supplied as mixed materials and used in that form.
The size of the device can be adjusted to meet linear cross sectional velocity (flow rate) and empty bed contact time requirements for a given application. In an exemplary embodiment the device has a nominal tube diameter of 3 inches with a nominal 12-inch internal length from screen to screen with a single tube volume of about 1.4 L or 2.8 L for the dual cartridge. For ion exchange applications the cross sectional area of the tube will allow for a linear cross sectional velocity of from approximately 1 to about 4 L/min. Higher or lower flow rates may be utilized depending on feed solution characteristics and desired effluent quality. Flow rates can be adjusted externally to accommodate desired empty bed contact time relative to feed solution characteristics and effluent quality requirements. For example, a flow rate of 1.0 L/min. would have an empty bed contact time of 2.8 minutes when activated carbon is used as the media.
The flow distributors and collectors of the housing of the present invention contribute greatly to the efficiency of operation. Fluid passing through the bottom screen 16 travels to the permeate plenum 22 via flow collector 21 , which splits the stream into two opposing directions which cancel each other to provide an even flow pattern. Thus, flow collector 21 collects fluid from both clockwise and counterclockwise directions to eliminate or reduce the potential for channeling in the upstream media. Once the fluid reaches permeate plenum 22 it travels upwardly to top end cap 12 , then passes through a flow distributor 23 for clockwise and counterclockwise fluid distribution over top porous screen 16 . Once enough fluid is collected and pressure is generated, the fluid passes downwardly through porous screen 16 and the media located in the second cylinder. Fluid passing through the bottom porous screen 16 of the second cylinder passes through yet another flow collector 25 , which functions in the same fashion as flow collector 21 to create even flow of the fluid from the media. The fluid than travels upwardly again in a second permeate plenum 26 to the top end cap 12 through outlet port 28 for delivery of the purified fluid. In addition to the advantages noted above, such flow collector/distributors further provide flow path for the solution should one of the openings be plugged or restricted with welding flash.
Two or more of the dual cartridge housings of the present invention may be placed in fluid communication with each in series whereby, for example, the outlet of a first housing is placed in fluid communication with the inlet of a second housing, the outlet of the second housing is placed in fluid communication with a third housing, and so on, so as to achieve further treatment stages.
The terms and expressions which have been employed in the foregoing specification are used therein as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding equivalents of the features shown and described or portions thereof, it being recognized that the scope of the invention is defined and limited only by the claims which follow. | An internally plumbed housing for containing fluid purification media especially suitable for the production of ultrapure water. The device may be installed in a system for the production of laboratory grade water or may be used with pressurized feed for the delivery of purified water or other fluids in multiple applications. | 2 |
RELATED APPLICATIONS
[0001] This application claims priority under 35 U.S.C. 120 as a divisional of application Ser. No. 12/471,381 dated May 24, 2009. The disclosure of which is incorporated herein by reference. Application Ser. No. 12/471,381 claims priority from provisional application No. 60/867,725 filed Nov. 27, 2006, which is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to computational geometry in general and to determining visibility of points from a predefined point of view in particular.
[0004] 2. Discussion of the Related Art
[0005] Computer graphics employ processing units to determine visibility of points. Visibility determination is the process of determining whether a particular point in space is visible from a specific point of view. Determining the visibility of a surface of an object quickly and efficiently has been a fundamental problem in computer graphics.
[0006] Determining visible points is useful for indicating field of view from a specific point, for defining shadow casting, for the gaming industry, for the security industry and the like. For example, finding visible points may result in a more clearly visible object enabling to see better the particular features, curves and shapes of the object. In an exemplary case, a computerized image depicting the face of a person can be processed such that the human face contours are visibly shown after the processing. Such processing may be changing the color of some points in case they are not visible, hence distinguishing visible points from non-visible points in the image. After changing the color of the points that are visible from a specific point of view, a person watching the image can then determine if the human face is shown or if the back of the human head is shown.
[0007] A point cloud is a set of three-dimensional points describing the outlines or surface features of an object that may be produced by a 3D digitizer. Alternatively, point cloud can also represent some properties in N dimensional space. Evidently, points cannot occlude one another unless they are collinear with the viewpoint. As a result, points in the point cloud are not considered hidden. However, once the surface from which the points are sampled is reconstructed (in 2D or 3D), it is possible to define which of the points are visible to a viewer having a predetermined point of view. A point cloud inherently contains information from which it is possible to extract the visibility of the points to a viewer having a predetermined point of view.
[0008] Current solutions achieve points visibility by constructing a surface from the points in the point cloud, and using the surface to determine which of the is points is visible. Reconstruction of the surface from the points requires considerable time and computation resources.
[0009] In addition, visibility of point clouds has been addressed in the context of rendering images or representations of objects. For example, rendering visibility maps that indicates whether one point can be viewed from another before the data is actually required. This is done by a matrix having values representing the level of visibility from a viewpoint. This way, runtime of O(l) is required to receive an answer concerning visibility and runtime of at least O(n 2 ) is required to prepare the matrix. No solutions having runtime of O(n log n) are suggested in the art. Moreover, camera rotation or change in the field of view requires time-consuming visibility recalculation.
[0010] Therefore, it is desirable to provide a method and apparatus for efficiently determining the visible points without constructing a surface of points. Further, such method and apparatus are desired to be implemented using less memory, low complexity (e.g. O(n log n)) and be independent of camera rotation.
SUMMARY OF THE PRESENT INVENTION
[0011] The subject matter discloses a method for determining points that are visible from a specific point of view. The method comprises a step of inverting at least a portion of the image thus generating an inversed object. Each point in the object has a parallel point in the inversed object. The next step is determining the convex hull of the inversed object. Each point in the convex hull has a parallel point in the original object that is likely to be visible from the point of view. In some cases, additional conditions are applied on the points in the convex hull. For example, the size of the angle between two neighboring points to the examined point in the convex hull.
[0012] Determining visible points is also useful for determining shadow casting since the viewpoint may also function as a light source. Hence, visible points are illuminated by a light source located in the viewpoint. Performing the convex hull requires runtime of O(n log n) while other methods for determining is visible points require runtime of O(n 2 ). An image-detecting device such as a camera preferably takes the image in case it is a 2D representation. A memory unit within the camera or within a computing device to which the image is sent or copied preferably performs the process of determining the visible points.
[0000] The subject matter discloses a method of determining whether a specific point in a computerized image is visible from a viewpoint; said image is represented as a point cloud, the method comprising: performing inversion on points located in the vicinity of the specific point thus creating a computerized inversed object, each point in the vicinity of the specific point is translated to a parallel point in the computerized inversed object; defining a convex hull of the inversed object; determining if the specific point is visible from the viewpoint according to the position of its parallel point on the convex hull relative to its neighbor points.
The method may further comprise a step of applying an at least one condition on the parallel point of the specific point before determining that the specific point is visible.
The condition is comparing the angle between the parallel point of the specific point and two neighboring points in the point set composing the convex hull to a predetermined value; a line between the point and the viewpoint divides the angle. The method further comprises a step of coloring the specific point in case it is determined visible from the viewpoint.
The method further comprising a step removing the specific point from the computerized image in case said point is not determined visible from the viewpoint.
The method further comprises determining shadow casting of the specific point by determining the point is visible from a viewpoint representing a light source. The inversion is a spherical inversion.
It is another aspect of the subject matter to disclose a method for determining an optimal location for positioning an image capturing device within a volume, the method comprising: obtaining a plurality of points to be visible from the image capturing device; performing inversion on points located in the vicinity of the plurality of points thus creating a computerized inversed object, each point in the vicinity of the plurality of point is translated to a parallel point in the computerized inversed object; defining a convex hull of the inversed object; determining if a point of the plurality of points is visible from the viewpoint according to the position of its parallel point on the convex hull relative to its neighbor points; repeating said determining for multiple locations within the volume, determining whether a predetermined set of points is visible from each location; selecting the optimal location of the image capturing device based on the results of said repeated determining.
The method comprises determining visibility of the plurality of points by indicating the number or percentage of visible points of the plurality of points is higher than a threshold.
The number of points of the plurality of points that are visible from the determined location is higher than the number of points in the plurality of points that are visible from other locations.
The subject matter discloses a method for determining the amount of light falling on an at least one point using the method of claim 1 , the method comprises: determining direct illumination by determining visibility of the at least one point from a first set of points acting as a light source; locating a second set of points that are determined to be visible from the first set of points; determining indirect illumination by determining visibility of the at least one point from the second set of points acting as a source of reflecting light; setting the amount of light falling on the at least one point based on it being directly illuminated or indirectly illuminated.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Exemplary non-limited embodiments of the disclosed subject matter will be described, with reference to the following description of the embodiments, in conjunction with the figures. The figures are generally not shown to scale and any sizes are only meant to be exemplary and not necessarily limiting. Corresponding or like elements are optionally designated by the same numerals or letters.
[0014] FIG. 1 shows computational elements implementing a method for determining visible points from a viewpoint, in accordance with an exemplary embodiment of the disclosed subject matter;
[0015] FIG. 2 , illustrates a flow chart of a method for determining visibility of points from a viewpoint, in accordance with an exemplary embodiment of the disclosed subject matter;
[0016] FIG. 3 is an illustration of a spherical inversion of a cat, in accordance with an exemplary embodiment of the disclosed subject matter;
[0017] FIG. 4 shows a convex hull of the palm of a hand as disclosed in the subject matter, in accordance with an exemplary embodiment of the disclosed subject matter;
[0018] FIGS. 5A and 5B show a convex hull performed on two different shapes performed with the same inversion, in accordance with an exemplary embodiment of the disclosed subject matter;
[0019] FIGS. 6A and 6B illustrate the visibility of points from different viewpoints, in accordance with an exemplary embodiment of the disclosed subject matter; and,
[0020] FIG. 7 , illustrates shadow casting of an image performed after visibility determination, in accordance with an exemplary embodiment of the disclosed subject matter.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0021] The disclosed subject matter describes a novel and unobvious method for determining visible points in a point cloud referring to an object.
[0022] In a computerized image containing an object, it is complicated to determine whether a specific point or portion of an image is visible from a predetermined point of view. A captured image may be insufficiently clear and a person watching the image or a computer handling watching the image cannot define important data related to the image. For example, determining whether a portion of the image is visible from a specific point of view or whether a point in the image may be illuminated by a light source located at another point, or whether an obstacle, such as another object, occludes them.
[0023] The technical solution to the above-discussed problem is performed in a two-step algorithm. The first step is inversing an object in the image, a portion of the image, or the vicinity of a specific point. After an object is inverted, each point in the object has a parallel point in the inversion. Then, having an inversed shape, the next step is obtaining a convex hull of the inversed shape. The points in the original shape that have parallel points in the convex hull are likely to be visible.
[0024] FIG. 1 illustrates a computerized environment 100 implementing methods for determining the visibility of points in a computerize image represented by a point cloud, according to an exemplary embodiment of the subject matter. The point cloud can be acquired from other sources such as 3D scanners, stereo or range cameras, databases and the like. Assuming each point in a point cloud can be distinguished by coordinates or by its location in the point cloud, such data is preferably stored prior to the process of finding the visible points. Computerized environment 100 comprises an I/O device 110 for capturing an image using an imaging device 115 capturing a captured image 117 . The captured image 117 is transmitted to a memory 120 , where a processing unit 130 handles the image. Processing unit 130 performs inversion on at least a portion of the captured image, for example, a spherical inversion. Multiple inversions and the rules concerning the resolution and other characteristics related to the inversion may be stored in storage 140 . Each point in the original object from captured image 117 has a parallel point in the inversed object. Next, processor 130 determines a convex hull of the inversed object. A point in captured image 117 is likely to be visible in case its parallel point is part of the point set composing the convex hull of the inversed image. After determining visible points, some of the pixels in the image may be colored or otherwise processed to better define the visible points from the non-visible points. In an exemplary embodiment of the subject matter, the non-visible points are removed from captured image 117 to generate a processed image 145 . In other embodiments, processed image 145 may modify data related to visible points, such as enlarging visible points, highlighting visible points and the like. Processed image 145 may be displayed on monitor 150 . The results may be used from further computational units or for other applications such as navigation.
[0025] One example of inversion is Spherical Flipping as described in Mesh segmentation using feature point and core extraction KATZ, S., LEIFMAN, G., AND TAL, A. 2005. The article was published in Visual Computer 21, 8-10, 865-875, which is hereby incorporated by reference. Another example of an inversion is a simple inversion in which the radius r is inversed into l/r. Such simple inversion is performed using the equation
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[0026] Typically, when performing an inversion, the computational entity generates an approximately elliptical or spherical with the viewpoint in the center or in one of the focuses of the shape.
[0027] FIG. 2 is a flow chart of a method of determining visibility of points on an object from a viewpoint, according to an exemplary embodiment of the subject matter. In step 205 , data related to the object and the point is stored in storage 140 . Such data may be coordinates of the points in the point cloud, the number of points in the point cloud, coordinates of the viewpoint, and the like. Next, in step 210 , the application handling the process of determining visibility of points performs inversion on the object. As a result of the inversion, a new set of points is generated. In an exemplary embodiment, the number of points in the new set of point is equal to the number of points in the point cloud representing the object. Preferably, each point in the point cloud representing the object has a parallel point in the new set of point related to the inversed object. On step 220 , a convex hull is defined from the inversed object. In one embodiment of the subject matter, all the points that have parallel points in the convex hull of the inversed object are visible from the viewpoint. In other embodiments, as shown on step 230 , other conditions are applied to the points that have parallel points in the convex hull before determining visibility. One example for a condition applied on a point is determining whether the angle between the parallel point in the convex hull and the two neighboring points in the hull is lower or higher than a threshold. A line between the parallel point and the viewpoint divides the angle. Once the condition is satisfied, on step 240 the application determines whether the point is visible from a specific viewpoint. On step 250 , the visible points are colored when shadow casting is performed. In some exemplary embodiments, the level of visibility may be determined as a function of the portion of the point occluded by other points in the point cloud. Hence, visible points may be colored in a color different from non-visible points.
[0028] FIG. 3 illustrates a spherical inversion according to an exemplary embodiment of the subject matter, in which a cat-shaped circumference surrounding a viewer located at a viewpoint in the center 310 of approximate sphere 320 . The circumference is inversed outside in an approximate sphere 320 having center 310 . The result of this specific inversion is that each point that assembles the cat-shaped circumference has a parallel point outside approximate sphere 320 . In FIG. 3 , the article surrounding the object is approximate sphere 320 . In some inversions, the parallel points may reside within the article surrounding the object. In spherical inversion, a parallel point resides on the same line leading from center 310 to a point in the original object that was inverted. Further, the distance between an original point on the cat-like circumference of the object to approximate sphere 320 and the parallel point of the same original point to approximate sphere 320 is equal or has a constant ratio. Each point on the cat is inside approximate sphere 320 , the parallel points are outside the sphere, for example, the point indicating a portion of the cat's head 332 has a parallel point 334 outside approximate sphere 320 , satisfying the conditions described above. In this exemplary embodiment, the distance between point 332 and sphere 320 is equal to the distance between parallel point 334 and sphere 320 . It is noted that point 332 is in relative proximity to approximate sphere 320 ; hence, parallel point 334 is closer to approximate sphere 320 than the parallel points in its vicinity. Similarly, point 342 is relatively far from approximate sphere 320 and close to center 310 , parallel point 344 resides in the proximity of the cat's inversion, relative to approximate sphere 320 . Approximate sphere 320 may be a circle, elliptical, or combine a polygonal and elliptical shape.
[0029] FIG. 4 , shows a convex hull of a palm of a hand 400 . The term convex hull according to the disclosed subject matter refers to a set of points is the intersection of all convex sets which contain the points. Another definition may be a set of points that may reside on lines generated by tensing a band over an object. An alternative definition may that the convex hull of shape S is the unique convex polygon which contains S and whose vertices are from SA convex hull can also be depicted as points creating a polygon outside an elliptical or semi-elliptical shape or volume, in two or three dimensions.
[0030] The result of the convex hull is a set of points. In the exemplary embodiment shown in FIG. 4 , points 410 , 420 , 430 440 , 450 , 460 and 470 are at least a subset of the points contained within the set of points assembling the convex hull of palm 400 . The lines connecting the points in the convex hull belonging to the set of points are outside palm 400 . For example, line 415 connects point 410 and point 420 . The lines connecting the points are useful in determining which of the points in the point set has a visible parallel point in the object. Hence, data related to the lines, such as directions, coordinates, angles toward a specific point or line, offsets and the like is stored in storage and preferably utilized when determining points' visibility.
[0031] FIGS. 5A and 5B show convex hulls 507 , 557 , respectively surrounding two different shapes performed with the same inversion. The figures exemplify the difference in determining visible points in contrast to non-visible points from a similar viewpoint 510 , 550 using similar inversion methods. FIG. 5A depicts a heart shaped object 503 having center 510 . Center 510 is a viewpoint of the points in the point cloud that compose object 503 . Parallel point 522 is the point generated by inverting point 520 . Parallel point 522 lies on convex hull 507 and as a result, point 520 is likely to be visible from center 510 . Similarly, points 530 and 540 are likely to be visible from center 510 since parallel points 532 and 542 reside on convex hull 507 . A Point is determined to be visible if the angle between the two neighboring points of the point towards the viewpoint is smaller than a threshold value. In this case, the angle is defined by summing β k and β j . The center of the angle is parallel point 532 , so the point to be determined visible or not visible is point 530 . Since the angle is smaller than 180, which is the threshold in the exemplary embodiment, point 530 is determined visible from center 510 . Another way for defining the angle between the two neighboring points and the point that is specifically determined as visible or non-visible is to determine whether the angle points at the viewpoint or not. For example, when determining if point 530 is visible, the angle is centered in point 532 , the parallel point of point 530 .
[0032] FIG. 5B discloses an object 555 viewed from a center 550 . The points belonging to object 555 have parallel points in an inversed object 557 . For example, point 560 has parallel point 565 that resides within convex hull 557 , the inversion of object 555 . Similarly, points 570 and 580 of object 555 have parallel points 575 and 585 , respectively. In order to determine the visibility of point 570 from center 550 , the angle between the two neighboring points of parallel point 575 is calculated and compared to a predetermined threshold. In this case, the threshold is 180 degrees and the angle is bigger than the threshold. It is shown that line 590 that passes between neighboring parallel points 565 and 585 , fully resides within inversed object 557 . Determining the number or percentage of points contained in the line between the neighboring points that reside in the inversed object and comparing the result to a predetermined threshold is an alternative test in determining that a point in the convex hull is visible.
[0033] The steps described above, mainly of inversing the object, determining a convex hull and determining visibility of points that have parallel points on the convex hull are preferably performed by a computerized application. The image processing applications comprise software components written in any programming language such as C, C#, C++, Matlab, Java, VB, VB.Net, or the like, and developed under any development environment, such as Visual Studio.Net, J2EE or the like. It will be appreciated that the applications can alternatively be implemented as firmware ported for a specific processor such as digital signal processor (DSP) or microcontrollers, or can be implemented as hardware or configurable hardware such as field programmable gate array (FPGA) or application specific integrated circuit (ASIC). The methods can also be adapted to be executed on a computing platform, or any other type of computing platform that is provisioned with a memory device 120 , a CPU 130 , and several I/O ports 110 as noted above.
[0034] Referring now to FIGS. 6A and 6B , illustrating the result of the methods described above. Both figures show visibility of points from different viewpoints. Visible points are shown in gray, while non-visible points are shown in white. FIG. 6A shows viewpoint 610 and a plurality of points near viewpoint 610 . Some points, such as point 612 , are visible from viewpoint 610 . Obstacles, such as obstacle 614 , prevent visibility of other points near point 610 . One example for a non-visible point is point 616 , hidden behind an obstacle. FIG. 6B shows the same obstacles as in FIG. 6A and a different viewpoint 620 . Hence, the visibility of points differs, by the number of points, as well as their location. Visible point 622 is not visible in the same location in FIG. 6A , while non-visible point 626 is visible in the same location in FIG. 6A .
[0035] FIG. 7 , illustrates shadow casting of an image, performed after visibility determination as described above. Shadow casting is provided according to the visibility determination, since visibility can be transformed into an amount of light emitted to a point. For example, in case a point in a point cloud is visible, it may indicate that the sun or another light source lights the point or points in its vicinity. In other implementation of visibility determination, a visible point may be colored to better distinguish the visible point from other point. FIG. 7 shows dinosaur 700 viewed from viewpoint 710 . Visible points, such as point 720 , are colored white, while non-visible points such as point 730 are colored in a dark color, such as black. Coloring pixels or points in an object as a function of the points' visibility is parallel to determining shadow casting, since visibility from one viewpoint has a similar effect to light emitted from the same view point on an object. The points that are visible from a viewpoint have correspond to points that are illuminated in case a light source resides in the viewpoint.
[0036] One technical effect of the subject matter is the ability to determine visibility for both dense point clouds and sparse point clouds without creating a new image or creating a three-dimensional surface.
[0037] Another technical effect is that the algorithm disclosed above can be applied on multi-dimensional representations. In such cases, the complexity of generating a convex hull is higher than O(n log n). In both cases, known methods such as reconstruction or image rendering are generally difficult and time consuming.
[0038] Another technical effect is that the methods described above are independent from change in the rotation or field of view of a camera or another image processing device used for capturing image data. Hence, the method and system of the disclosed subject matter do not require visibility recalculation. The viewpoint can be positioned either within or outside the point cloud.
[0039] One aspect of the invention is that it adaptively defines the shape of a region between a point and a viewpoint, which indicates the amount of visibility. In other words, “how much” of a point is visible.
[0040] The methods described above are computationally less complex. The first stage of the algorithm, inversion, requires runtime of O(n). The second stage, convex hull computation, requires runtime of O(n log n). Therefore, the asymptotic complexity of the algorithm is O(n log n).
[0041] Another technical effect of the subject matter is the ability to distinguish between two possible positions that produce very similar projections—looking towards or away from the camera. This ability is achieved by determining which points in a 3D object are visible and which points are hidden. By removing the hidden points from the image, or data related to the hidden points from the image, the only pixels displayed are those viewed from the specific viewpoint. Hence, in case the face is shown from a specific point of view, it can be indicated, either automatically or by a human, whether an object faces a viewpoint or not.
[0042] Another technical effect in the subject matter is the ability to determine the desired location of cameras. This is achieved by determining points visibility from multiple locations using the above described method, and comparing the number or percentage of visible points in each location. For example, in case one location has 22 visible points, it is preferred on another location with 18 visible points.
[0043] The invention can be extended to 3D or to any other number of dimensions. In 3D, instead of using two neighboring points, several neighboring points define the surface enclosing the empty volume. However, the algorithm of the disclosed subject matter uses the same convex hull construction.
[0044] Another technical effect of the disclosed subject matter is the ability to determine the amount of light falling on a surface, which takes into account not only the light fallen directly from a light source as performed when determining direct illumination, but also light which has undergone reflection from other surfaces in the world as performed when determining indirect illumination. Direct illumination can be obtained using the methods for determining points visibility to determine the visibility between a point source of light and the illuminated surface. Indirect illumination can be obtained using the same methods to determine the visibility between a first surface acting as a source of reflecting light and a second surface that is being illuminated. The global illumination of a surface can be determined as a function of the direct illumination and the indirect illumination determined using the methods described above.
[0045] While the disclosure 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 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 without departing from the essential scope thereof. Therefore, it is intended that the disclosed subject matter not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but only by the claims that follow. | A method for determining an optimal location for positioning an image capturing device within a volume, the method including, obtaining a plurality of points to be visible from the image capturing device, performing inversion on points located in the vicinity of the plurality of points thus creating a computerized inversed object, each point in the vicinity of the plurality of point is translated to a corresponding point in the computerized inversed object, defining a convex hull of the inversed object, determining if a point of the plurality of points is visible from the viewpoint according to the position of its corresponding point on the convex hull relative to its neighbor points, repeating said determining for multiple locations within the volume, determining whether a predetermined set of points is visible from each location, selecting the optimal location of the image capturing device based on the results of said repeated determining. | 6 |
CROSS-REFERENCE TO RELATED APPLICATION
[0001] The present application is based on and claims priority to U.S. Provisional Patent Application Ser. No. 61/823,630 filed May 15, 2013, the disclosure of which is incorporated herein by reference.
BACKGROUND
[0002] The present disclosure generally relates to a concrete mix that can be used in forming a variety of molded end products. More specifically, the present disclosure relates to a concrete mix that is formed including at least a portion of recycled porcelain, which can include pre-consumer and post-consumer porcelain.
[0003] Porcelain is a ceramic material made by heating raw materials including clay, glass and mullite at temperatures between 1200° C. and 1400° C. The toughness and strength of porcelain comes from the inclusion of glass and the mineral mullite within the fired body of the finished product. Porcelain as a finished product can be in many forms, including but not limited to, kitchenware such as sinks, vanity tops, and bathroom fittings such as tubs, sinks and commodes. Porcelain is an excellent dielectric and is the material of choice for high voltage insulators carrying cable/conductors where voltages can exceed 15,000 volts. Porcelain is also used in buildings in the form of tiles, signs and large translucent wall panels.
[0004] At the end of its life, porcelain is currently discarded and dumped into landfills. Recycling processes and end uses for recycled porcelain have not been developed for such a material. Thus, porcelain is generally considered unsalvageable and therefore unsellable. As a direct result, landfills are filled with materials that are not recyclable, which is certainly an undesirable condition given the limited space allowed for landfills.
[0005] As is well known in today's world, recycling is an established practice. For example, for our mineral assets and wood by-products, such as paper and cardboard, this practice is critical to maximize our natural resources. By contrast, we have been unable to recycle materials such as porcelain, since the composition of porcelain is clay, glass and mullite. Porcelain has a very high heat history that renders it unmalleable in any subsequent forming process.
[0006] The present disclosure is the result of experimentation with combinations of various materials and developing a process that incorporates a composition of previously unrecycled and unsellable post-consumer and post manufactured porcelain materials.
SUMMARY
[0007] A new and heretofore unknown processing method has been developed that provides for the immediate consumption and reuse of porcelain materials from both post-manufacturing and post-consumer materials. Blend ratios of porcelain and other materials exceeding 65% have been achieved with the method of the present disclosure. A post-consumer concrete mix is disclosed consisting of sized granular porcelain kernels that are formed from crushed post-consumer and post-manufacturing finished porcelain materials such as sinks, vanity tops, and all unsalvageable reclaim from any manufacturing facility. The present disclosure also contemplates utilizing any porcelain product that cannot be used in the manner in which it was intended as a source to generate the porcelain kernels. As an example, a porcelain sink that was damaged in transit and cannot or will not be used as a sink any longer can be used as part of the method. The porcelain may be a pre-consumer or post-consumer product of any size, color, shape, or age.
[0008] The porcelain in its resized and treated form is blended with a customized cement and a customized sand slurry to form a countertop and/or any other concrete product, such as firewalls or other decorative and structural concrete products for use in residential and commercial applications.
[0009] The method of blending together of previously considered unsellable and unsalvageable materials to form a commercial and/or residential concrete products, such as a countertop, forms the basis of the present disclosure. The recycled material is porcelain, which is crushed from toilets, sinks, vanity tops, and any unsalvageable porcelain from a manufacturing facility. The porcelain supply can also include any porcelain product that cannot be used in the manner in was it was intended. As an example, a porcelain sink that was damaged in transit and cannot/will not be used as a sink any longer will be used as a supply of porcelain. The porcelain shall be a pre-consumer or post-consumer product of any size, color, shape, or age.
[0010] The concrete mix that includes the recycled porcelain can be used to form a wide variety of molded end products. Such end products, by example, can include countertops, custom moldings, such as flame retardant hearths, heat pads, and enclosures for fireplaces. The end products can also include roofing tiles, floor tiles and any other product currently being formed from molded concrete, building blocks, redi-mix concrete, wet/dry cast concrete, glass fiber reinforced concrete.
[0011] The present disclosure incorporates lightweight composition of materials using not less than 30% of post-consumer and post manufactured materials. In one embodiment of the disclosure, the concrete mix includes treated porcelain kernels that have a size in the range of 0.0117″ to 0.75″. The porcelain kernels are mixed with cement and sand and are provided as a pre-formed concrete mix. The pre-formed concrete mix can be blended with water and used to create any type of molded concrete product.
[0012] In accordance with the method of the present disclosure, a supply of post-consumer or post-manufactured porcelain is received at a recycling location. The supply of porcelain is processed at the recycling location to create a supply of porcelain kernels. The porcelain kernels are sorted and further processed such that the porcelain kernels have a preferred sizing in the range of 0.0117″ to 0.75″.
[0013] Once the porcelain kernels have been sorted and sized, the porcelain kernels are mixed with at least cement and sand to create a concrete mix. The concrete mix including the porcelain kernels created from recycled porcelain products is then packaged for later use in forming an end product.
[0014] This disclosure teaches a method and process of utilizing recycled porcelain as a component part of a materials mix including cement that may or may not include recycled fly ash, sand slurry, sized stones such as pea gravel, Portland cement and water.
[0015] The materials mix may be wet formed into numerous finished products including, but not limited to, such end products as countertops, fireplace surrounds and building blocks.
[0016] The inclusion of porcelain in material mixes as illustrated provides benefits including a significant weight reduction, greater flame retardancy, increased thermal insulating factors and R-values and a greatly improved and even mixture of the various components when the materials are wet formed. In addition to these benefits, the natural buoyancy and light weight of porcelain results in a more even disbursement of the porcelain kernels throughout the entire concrete end product which results in a more structurally sound and stronger end product compared to the use of pea gravel or buck shot as the aggregate. When the end product is polished, the evenly disbursed and exposed kernels provide for a more visually pleasing appearance for the end product as well.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The drawings illustrate the best mode presently contemplated of carrying out the disclosure. In the drawings:
[0018] FIG. 1 is a schematic view of a countertop created in accordance with the present disclosure;
[0019] FIG. 2 is a magnified, section view of the concrete formed utilizing the concrete mix of the present disclosure:
[0020] FIG. 3 is a section view illustrating a sample mold used to form a concrete countertop utilizing the concrete mix of the present disclosure;
[0021] FIG. 4 is a section view similar to FIG. 3 showing the disbursement of the porcelain kernels within the molded countertop; and
[0022] FIG. 5 is a flowchart illustrating the steps utilizing the method of the present disclosure.
DETAILED DESCRIPTION
[0023] FIG. 1 illustrates one potential use for a concrete end product utilizing the concrete mix of the present disclosure. Although one type of concrete end product (countertops) is illustrated in FIG. 1 , it should be understood that various different types of end products could be formed utilizing the concrete mix of the present disclosure. Theses concrete products can include both decorative and structural products that are typically formed from concrete.
[0024] In the embodiment shown in FIG. 1 , the concrete mix is used to form a countertop 10 that can be installed in a kitchen 12 . The countertop 10 includes a cutout that can receive a sink 14 . The countertop 10 includes an edge surface 16 that is formed to provide a decorative and pleasing appearance.
[0025] Presently, it is known to form countertops 10 such as shown in FIG. 1 from various compositions of material that form concrete. Typically, concrete includes a mixture of sand, cement, water and an aggregate material, such as stone or pea gravel. In accordance with the present disclosure, the concrete mix used to form the countertop 10 includes a mixture of cement, sand, water and porcelain kernels formed from recycled porcelain end products.
[0026] Referring now to FIG. 2 , a section view of the concrete formed in accordance with the present disclosure includes the series of porcelain kernels 18 bound together by the mixture of cement, water and sand which forms the binding material 20 between the separate porcelain kernels 18 . The porcelain kernels 18 are illustrated having irregular outer surfaces that are created during the crushing of porcelain end products that are being recycled to provide the source of porcelain for the concrete mix. The specific shape of the individual porcelain kernels 18 varies depending upon the processing techniques utilized and the source of recycled porcelain.
[0027] In accordance with the present disclosure, the porcelain kernels 18 are formed from porcelain products that are being recycled to create the concrete mix. Throughout the present disclosure, the term “recycled porcelain” will be used to refer to porcelain obtained from both post-consumer porcelain products as well as pre-consumer porcelain product or waste. As an example, a post-consumer porcelain product, such as a sink, vanity top, toilet or other similar type of porcelain product can be used to form the porcelain kernels 18 . In addition to post-consumer porcelain products, the porcelain kernels 18 could also be generated from post-manufacturing, pre-consumer porcelain products that cannot be used in the manner which was intended. As an example, a porcelain sink that was damaged in transit or at the manufacturing facility and cannot be used as a sink could be utilized as a recycled supply to create the porcelain kernels 18 . The porcelain used to create the porcelain kernels may be pre-consumer or post-consumer products of any size, color, shape or age.
[0028] In the embodiment shown in FIG. 2 , the porcelain kernels are formed from recycled pre- or post-consumer products. It is desired that the porcelain kernels 18 have a size A shown in FIG. 1 in the range of 0.0117″ to 0.750″. In the most preferred embodiment, each of the kernels will be in the range of 0.265″ to 0.375″. The size of the porcelain kernels will affect the strength and durability of the concrete formed from the porcelain kernels 18 created from the recycled porcelain material. In the embodiment shown in FIG. 2 , the countertop, or other molded product, formed from the concrete mixture that includes the porcelain kernels will have a weight savings of approximately 30% compared to similar commercial offerings for countertops, such as those formed from granite, marble, concrete, limestone, quartz or soap stone. In addition to the weight savings, an end product that is formed from the concrete mix including the porcelain kernels will increase the fire rating of the product by as much as 50% as compared to concrete formed with stone or pea gravel. The use of the porcelain kernels in the concrete shown in FIG. 2 creates a thermal break in the concrete unit's substrate, which leads to the increase in the fire rating.
[0029] In addition to being used as the source of aggregate in the concrete mix, it is contemplated that the recycled porcelain could be ground into very small pieces or particles such that the recycled porcelain would have the general consistency and texture of sand. In such an embodiment, the fine particle recycled porcelain could be used in the place of sand when forming concrete. Such an embodiment would increase the amount of recycled components in the concrete mix.
[0030] When a concrete product, such as a countertop, is formed from the concrete mix shown in FIG. 2 , the countertop will qualify for the LEADS Program (Leadership In Energy And Environmental Design) through the U.S. Green Building Institute. The current qualification requires that the products must include a minimum of 20% post-consumer products or 50% post-industrial. The concrete mix in accordance with the present disclosure includes a minimum of 35% post-consumer products. The 35% post-consumer products include both recycled porcelain and cement that may or may not include recycled fly ash. Additional LEAD points will be given when the credit level requirements for the recycled content are exceeded, such as if the recycled porcelain and cement exceeds the 35% threshold.
[0031] In accordance with one embodiment of the present disclosure, the concrete mix includes porcelain kernels that constitute at least 35% of the mixture by weight. The concrete mix will include a mixture of the porcelain kernels, cement and sand. The porcelain kernels will form at least 35% of the mixture by weight.
[0032] In yet another embodiment that maximizes the amount of recycled components used in the concrete mix, a portion of the cement could be replaced with fly ash and the sand could be replaced with recycled porcelain ground into fine particles. Such an embodiment would increase the number of LEAD points.
[0033] When the concrete mix is used to form countertops, such as shown in FIG. 1 , the countertop can be polished to expose the pores formed in the recycled porcelain kernels. The pores thus provide a visually pleasing appearance to the top surface of the countertop.
[0034] In addition to utilizing the concrete mix for countertops, such as shown in FIG. 1 , it is contemplated that the concrete mix including the recycled porcelain could be utilized to form other end products, such as roofing tiles, vertical concrete columns or pillars, plaster mix, redi-mix, stucco, floor tiles and any other type of end product that is currently being formed from concrete that includes stone aggregate and/or sand. As described above, the concrete mix including the porcelain kernels will have approximately 35% less weight and thus can be utilized in applications in which the weight of a concrete product previously prohibited the use of concrete.
[0035] FIG. 3 illustrates a cross-section view of a countertop mold that will utilize the concrete mix of the present disclosure. In the embodiment shown in FIG. 3 , an expanded metal/diamond mesh 22 is utilized within the concrete mold. In addition to the mesh 22 , the mold can also include concrete wire 24 and rebar 26 to provide further structural integrity for the product formed from the concrete mix. In the embodiment shown in FIG. 3 , the concrete wire has 6″×6″ openings or smaller and the wire has a diameter of between ⅛″ and 3/16″. In the embodiment illustrated, ⅜″ rebar 26 is included for structural purposes. However, it is contemplated that the rebar 26 could be eliminated while operating within the scope of the present disclosure.
[0036] In the embodiment shown in FIG. 3 , the product 28 has an overall thickness B of approximately 1.75″ at a minimum. The product 28 has a first layer 30 between the top surface 32 and the mesh 22 . In the embodiment shown, the top layer 30 has a thickness of approximately 0.50″. An intermediate layer 34 formed between the mesh 22 and the rebar 26 has a thickness of approximately 0.75″ while a third layer 36 between the rebar 26 and the bottom surface 38 has a thickness of approximately 0.50″. Although exemplary dimensions are shown in the embodiment of FIG. 3 , it should be understood that the thickness of the product 28 could be varied depending upon user requirements.
[0037] FIG. 4 illustrates the product 28 as including the porcelain kernels 18 distributed throughout the thickness of the product. The porcelain kernels 18 are balanced and equally distributed throughout the thickness B of the end product 28 . Each of the porcelain kernels 18 , as previously discussed, is a fractured component and is not of a smooth, defined surface. The fractured outer surface of the porcelain kernels 18 enhances the adhesion of the cement within the concrete mix.
[0038] FIG. 5 illustrates one method of creating the concrete mix in accordance with the present disclosure. As illustrated in FIG. 5 , the method first includes the step of receiving recycled post-consumer and/or pre-consumer porcelain products, illustrated by reference numeral 40 . The post-consumer products can include various different types of finished materials formed from porcelain, such as sinks, vanity tops, toilets or any other type of product that is formed from porcelain. Although step 40 shows the use of post-consumer and pre-consumer products, it should be understood that any other porcelain product that is currently undesirable and is being discarded could be utilized. As an example, pre-consumer products, such as a sink that is damaged in transit or during the manufacturing process and can no longer be used for its intended purpose, could be part of the porcelain products received in step 40 .
[0039] Once the porcelain products being recycled and received in step 40 , the porcelain products are processed to create porcelain kernels. Typically, this processing will include crushing and breaking of the consumer product that is formed from porcelain. During this processing step 42 , the porcelain products are crushed until the kernels reach a desired kernel size. In step 42 , the method sorts the kernels such that kernels smaller than a desired size and those larger than a desired size are discarded. Kernels that have a size too large are returned for further processing while kernels of a size less than a minimum are discarded for other use. As discussed previously, the desired size for the porcelain kernels is in the range of 0.0117″ to 0.750″. The most preferred size range for the porcelain kernels is in the range of 0.265″ to 0.375″.
[0040] Once the desired porcelain kernel sizes have been separated, the porcelain kernels are combined with cement and sand to form the concrete mix, as shown in step 46 . Although a concrete mix is described as including sand, the mix could be formed without sand and could incorporate very fine particles of recycled porcelain. As indicated above, it is desired that the porcelain kernels form at least 35% of the concrete mixture. Further, the concrete mix can also include a cement/fly ash mixture that further increases the recycled components of the concrete mix. In an embodiment in which both the porcelain kernels and cement/fly ash are drawn from recycled products, it is desirable that the combination of the porcelain and the recycled cement/fly ash constitute at least 65% of the mix by weight.
[0041] Once the concrete mix is formed in step 46 , the concrete mix is packaged in step 48 for use in forming concrete products. The packaging step 48 can place the concrete mix into 50 lb. bags, or any other size as desired. Alternatively, the packaging step can be eliminated and the concrete mix used immediately to form concrete products, such as countertops.
[0042] Once the concrete mix has been packaged, the concrete mix can be shipped or sold to concrete countertop manufacturers and installers for the creation of concrete countertops having a desired shape and size. The concrete mix can be dyed or colored to meet any decorative look for a home or business owner.
[0043] In addition to utilizing the concrete mix for forming countertops, it is understood that the concrete mix could be utilized to form many other different types of decorative and structural concrete products while operating within the scope of the present disclosure.
[0044] This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to make and use the invention. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims. | A concrete mix for use in forming molded concrete end products is disclosed. The concrete mix includes treated porcelain kernels, cement and sand. The treated porcelain kernels are formed from recycled and currently unusable porcelain products. The porcelain products are crushed and processed to create porcelain kernels having a desired size. The porcelain kernels having the desired size are mixed with cement and sand and the concrete mix is packaged for subsequent use. The concrete mix including the porcelain kernels formed from recycled porcelain products allows the porcelain end products to be recycled while providing concrete products that have lighter weight and greater flame resistance. | 2 |
This application is a division of and claims the benefit of U.S. application Ser. No. 08/706,513, filed Sep. 4, 1996, U.S. Pat. No. 5,851,857 the disclosure of which is incorporated by reference.
BACKGROUND OF THE INVENTION
The present invention relates to power switching devices. More specifically, the present invention relates to a power switching device for high frequency applications which has a relatively low “on resistance.”
Metal-oxide semiconductor field effect transistors (MOSFETs) have become the standard power switching device because of their fast switching capabilities. Unfortunately, as the breakdown voltages of power MOSFETs increase, a correlative increase in device “on resistance,” R ON , is encountered. This undesirable increase is largely a result of the high resistivity of the semiconductor layer which makes the increase in breakdown voltage possible. Increased R ON , in turn, translates into conduction losses and increasingly inefficient operation. The relationship between R ON and the device breakdown voltage, V B , is approximated by the equation:
R ON ≈aV B 2.5 (1)
That is, for every doubling of V B , R ON is increased by a factor of 5.66. Thus, despite their favorable switching characteristics, at some breakdown voltage, standard power MOSFETs become too inefficient for high power operation.
In contrast, insulated gate bipolar transistors (IGBTs) have a lower effective RON than MOSFETs as a result of a four layer structure which facilitates the injection of minority carriers into the high resistivity region. Unfortunately, the injection of these minority carriers results in slower devices which cannot match the switching capabilities of MOSFETs. This is due to the delay required to build up enough minority carriers in the high resistivity region before an IGBT is fully turned on. Similarly, the IGBT experiences a delay turning off because of the time required for the same minority carriers to be removed from this region.
In addition, because the four layer structure of an IGBT is similar to that of a thyristor, if the concentration of minority carriers in the high resistivity region exceeds a certain threshold, the IGBT ceases to behave like a transistor and goes into a latching mode. This behavior is described in detail in U.S. Pat. No. 4,199,774, issued on Apr. 22, 1980, the entire specification of which is incorporated herein by reference. Several techniques have been employed to reduce the susceptibility of IGBTs to latching. One of the most effective techniques involves irradiating the device with electrons after completion of standard semiconductor processing. Other techniques include unique device cell layout, source ballasting, and increasing the doping of the body region of the device. For more detailed descriptions of some of these techniques please see Comparison of 300-, 600-, and 1200-V n-Channel Insulated Gate Transistors, Chow et al., IEEE Transactions on Electron Device Letters, Vol. EDL-6, No. 4, April 1985, pp. 161-163, and The Insulated Gate Transistor: A New Three-Terminal MOS-Controlled Bipolar Power Device, Baliga et al., IEEE Transactions on Electron Devices, Vol. ED-31, No. 6, June 1984, pp. 821-828, both of which are incorporated herein by reference in their entirety. Unfortunately, while these techniques have had varying measures of success in reducing latching susceptibility, the devices remain slower than MOSFETs operating at similar power levels.
A power switching device is therefore desirable which combines the switching speed of a power MOSFET with the low “on resistance” of an IGBT.
SUMMARY OF THE INVENTION
The present invention provides a power switching device which combines the switching speed of a power MOSFET with the low “on resistance” of an IGBT. Moreover, the switching device of the present invention is less susceptible to the above-described latching phenomenon than standard IGBTs. The operational characteristics of the switching device of the present invention are made possible by its unique structure which provides a power MOSFET and an IGBT in parallel in a single device. The devices share a common source/emitter region and a common gate. The drain of the MOSFET comprises a number of island regions adjacent the back side of the device, at which surface the island regions are surrounded by the collector region of the IGBT.
Moreover, by varying the size, shape, number, and alignment of the island drain regions, the operational characteristics of the device of the present invention can be made to be more like either the MOSFET or the IGBT depending upon the application. That is, if in a particular application a fast switching speed is more important than a low “on resistance,” the operational characteristics of the device can be adjusted toward the MOSFET end of the spectrum. This may be accomplished, for example, by increasing the size of the island drain regions. Alternatively, a similar effect may be achieved by aligning the island drain regions more closely with the gate of the device.
Thus, according to the invention, a switching device and a method for fabricating the same are provided. The switching device is fabricated in a semiconductor substrate with a front side and a back side. The switching device includes a first transistor which includes a first region adjacent the front side, a second region within the first region, the semiconductor substrate, and at least one island region adjacent the backside. The switching device also includes a second transistor which includes the first region, the second region, the semiconductor substrate, and a third region coupled to the at least one island region.
A further understanding of the nature and advantages of the present invention may be realized by reference to the remaining portions of the specification and the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic representation of a switching device designed according to the present invention;
FIG. 2 is a simplified illustration of the backside of a switching device designed according to a specific embodiment of the invention;
FIG. 3 is a cross-sectional view of a switching device designed according to a specific embodiment of the invention;
FIG. 4 is a cross-sectional view of a switching device designed according to another specific embodiment of the invention; and
FIG. 5 is a cross-sectional view of a switching device designed according to yet another specific embodiment of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 is a schematic representation of a switching device 100 designed according to the present invention. Switching device 100 is an integrated device which includes a power MOSFET 102 and an IGBT 104 connected in parallel. The devices share the same MOS gate 106 and the same region as the source of the MOSFET and the emitter of the IGBT, i.e., source/emitter node 108 . Device 100 also includes an intrinsic reversed diode 110 in parallel with both MOSFET 102 and IGBT 104 . Intrinsic diode 110 obviates the need for an external diode to be added across IGBT 104 as would typically be the practice.
FIG. 2 is a simplified illustration of the back side 200 of an N-channel switching device designed according to a specific embodiment of the invention. The substrate of the device is an N-type semiconductor crystal into which N+ island regions 202 are formed. At back side 200 , the N+ island regions are surrounded by a P+ doped region. In FIG. 2, island regions 202 are shown as circular. However, according to various embodiments of the invention, these regions may have any of a variety of closed shapes including, for example, ellipses, polygons, triangles, etc. The formation of N+ island regions 202 and the surrounding P+ area 204 may be accomplished sequentially by any of a variety of ion implantation or deposition techniques.
The designer may uniquely determine the operational characteristics of the switching device of the present invention for a particular application by controlling the size, shape, and number of island regions 202 . This is because the ratio of the island region area to the total back side area determines whether the device operates more like a MOSFET or an IGBT. This ratio R may be represented:
R=nA i /AT (2)
where n is the number is island regions, A i is the area of each individual island region, and A T is the total area of the back side of the device. According to various embodiments of the invention, the designer may vary the ratio R between 0 and 1. For R=0, the device is a standard IGBT. For R=1, the device is a standard MOSFET (if no P+ back side doping is used). The alignment of island regions 202 also affects the operational characteristics of the device and will be discussed below with reference to FIGS. 3 and 4.
FIG. 3 is a cross-sectional view of a switching device 300 designed according to a specific embodiment of the invention. Device 300 is formed in an N− semiconductor crystal 302 with P wells 304 formed in the front side thereof. N+ regions 306 are formed within P wells 304 . In the back side of crystal 302 N+ island regions 308 are separated by a continuous P+ region 310 . A collector/drain electrode 312 on the back side of crystal 302 electrically connects island regions 308 with region 310 . Gate electrode 314 and emitter/source electrode 316 are formed on the front side of crystal 302 with oxide layer 318 separating gate electrode 314 from the surface of crystal 302 . Similar device features in subsequent drawings will employ the same reference numbers.
The device features of FIG. 3 combine to form the device of FIG. 1 in the following manner. N+ region 306 A, P well 304 A, N− crystal 302 , and N+ island regions 308 combine to form MOSFET 102 . N+ region 306 A, P well 304 A, N− crystal 302 , and P+ region 310 combine to form IGBT 104 . Intrinsic diode 110 corresponds to P well 304 A, N− crystal 302 , and N+ island regions 308 . Edge of die termination for each device can be a continuous P+ region in the back side of the device and the corresponding N+ scribe line configuration in a standard MOSFET or IGBT device.
Switching devices made according to the present invention such as, for example, device 300 of FIG. 3, have advantages over conventional MOSFETs and IGBTS. A conventional high voltage MOSFET has a high “on resistance” R ON . A typical 1000V MOSFET with an area of 64 mmsq has an R ON of 1 ohm. A 1600V MOSFET with the same die area has an R ON of 3.24 ohms at 25° C. However, as the device heats up, R ON increases. At a junction temperature of 150° C., R ON typically doubles from its rating at 25° C. resulting in an R ON greater than 6 ohms; an unacceptably high value for many applications.
By contrast, and much like the back side P+ region of an IGBT, back side P+ region 310 of switching device 300 injects minority carriers, i.e., “holes,” into the N− region of crystal 302 , thereby reducing the resistance of the switch. The injection of minority carriers into the high resistivity region represented by the N− region is sufficient to reduce R ON of device 300 without slowing it down overly much. Of course, as discussed above, the designer may manipulate the size, shape, number, and alignment of N+ island regions 308 to increase or decrease the effects of minority carrier injection to suit a particular application. An example of such manipulation is described with reference to FIG. 4 .
FIG. 4 is a cross-sectional view of a switching device 400 designed according to another specific embodiment of the invention. Switching device 400 is similar to device 300 except that P+ region 310 is aligned with P wells 304 rather than gate electrode 314 . This configuration results in greater minority carrier injection, and thus device 400 acts more like an IGBT than device 300 . Conversely, the configuration of device 300 in which P+ region 310 is aligned with gate electrode 314 results in lesser minority carrier injection, and thus device 300 acts more like a MOSFET.
In yet another alternate embodiment, the spacing of regions 308 and 310 differs from those of P wells 304 such that no particular alignment occurs. Where precise control over the operational characteristics of the device is desired, the coincident spacing of device 300 or 400 is preferable to a device in which no such alignment may be accomplished. However, it is easier (and therefore cheaper) to manufacture a device without such alignment requirements. Thus, where a wider range of operational characteristics is acceptable, it is not necessary to require alignment of these device features.
The intrinsic diode formed in each of the above devices (i.e., diode 110 of FIG. 1) can be made a fast switching diode by one or a combination of several techniques. For example, the device may be irradiated with a high energy, i.e., greater than 2 mega electron volts (MEV), electron beam. “Deep traps” may also be incorporated in the device crystal by implantation, deposition, or evaporation followed by diffusion of heavy metal atoms such as, for example, gold and platinum. The diffusion step may employ conventional techniques or a rapid thermal process (RTP). Additionally, high energy implantation of ions such as, for example, He+ ions, or “alpha particles.” Any irradiation damage caused by any of these techniques may require a controlled anneal step for correction of the damage.
Even with the use of the above-described techniques to speed up the intrinsic diode, there are some applications for which it is too slow. Therefore, it may be desirable to block it off from operation. This may be accomplished by the formation of a P− layer 502 as shown in FIG. 5 . Switching device 500 is substantially identical to switching device 300 of FIG. 3 except for the introduction of P− layer 502 which blocks the intrinsic diode by isolating N+ island regions 308 from the N− region of crystal 302 . The effectiveness of the blocking is dependent, at least in part, on the net width of layer 502 . In addition, the doping concentration of layer 502 must be carefully controlled to ensure that sufficient hole injection by P+ region 310 will still occur, and that there is effective “emitter shorting” in the back side of the device by N+ island regions 308 . One method of forming layer 502 which facilitates achieving these goals employs an ion implantation and diffusion process. Following implantation in the back side of the N− crystal, the diffusion step brings P− layer 502 relatively deep within crystal 302 as compared to the diffusion depths of the front side regions 304 and 306 . If the doping concentration is relatively high and the net width of layer 502 is greater than about 5 microns, device 500 will tend to behave somewhat like a typical IGBT with a low V SAT (e.g., 2V) and a relatively slow turn-off time (500 ns). For relatively low doping concentrations and net widths less than 5 microns, device 500 will have a greater V SAT (e.g., 2.3-6V) and a much faster turn-off time (e.g., 50 ns), behaving more like device 300 of FIG. 3 .
One method for forming the back side structure of FIG. 5 includes the following steps:
1. Backside implantation of a low dose of boron for creation of P− layer.
2. High temperature (T>1100° C.) diffusion for longer than 12 hours to drive the boron to a depth of greater than 6 microns.
3. Masking and etching of back side to define openings for introduction of impurities for formation of N+ island regions.
4. Introduction of a high dose of N+ impurities (e.g., >1E15) either by ion implantation or by standard diffusion pre-deposition process to form N+ island regions.
5. Etching of the remaining back side oxide.
6. Deposition of boron either by ion implantation or diffusion pre-deposition. The relative concentrations of the boron and the N+ doping in the island regions are such that the N+ regions are not converted to P regions.
7. Diffusion of boron at T<1150° C. for less than 9 hours, the specific temperature and diffusion time of course being dependent upon the desired device characteristics. The shallower the diffusion, the higher the V SAT and the faster the device. For example, for depths of less than 5 microns for both the N+ island regions and the P+ backside region, V SAT ≈3-4V and the device turn-off time is approximately 200 ns. It will be understood that the order of formation of the N+ island regions and the P+ back side region may be reversed.
While the invention has been particularly shown and described with reference to specific embodiments thereof, it will be understood by those skilled in the art that the foregoing and other changes in the form and details may be made therein without departing from the spirit or scope of the invention. For example, the present invention has been described primarily with regard to an N-channel device. However, it will be understood that the invention may just as easily be implemented as a P-channel device with complementary doped regions and substrate. The scope of the invention should therefore be determined by reference to the appended claims. | A switching device is described having a semiconductor substrate with a front side and a back side. The switching device includes a first transistor which includes a first region adjacent the front side, a second region within the first region, the semiconductor substrate, and at least one island region adjacent the backside. The switching device also includes a second transistor which includes the first region, the second region, the semiconductor substrate, and a third region coupled to the at least one island region. | 7 |
FIELD OF THE INVENTION
The invention relates to a cleaning device, more particularly, to a cleaning head which is used to apply cleansing liquid onto a surface, to scrub the surface thus treated and to wipe and to remove residual waste cleansing liquid from it. More specifically, this invention relates to a cleaning head particularly suitable for cleaning surfaces which are flat, impervious and smooth.
BACKGROUND OF INVENTION
Glass, brass, granite, tiles and other materials which can be made to have a hard, smooth and impervious surface are widely used as mirrors, windows, walls or displays in both domestic and high-rise commercial buildings. The exterior appearance of premises or buildings is always regarded as a reflection of the image, personality or characteristics of their owners or occupants, regular cleaning of external surfaces are therefore required to maintain a clean, spotless and dust-free look. These surfaces are always shiny, either highly reflective or transparent, good cleaning would therefore require application of a suitable cleansing agent, scrubbing with a soft material such as foam, sponge, wool or cloth, and drying immediately after scrubbing to avoid residual stains.
Many of these surfaces are large and tall and are often found in business districts or shopping arcades where there is a high pedestrian turn-around rate. Conventional cleaning methods using ladder with bucket, mop and wiper become dangerous and inefficient. Furthermore, residual used liquid not completely removed will be collected at the edges and forming mouldy or rusty layer of residue deposit. There is therefore a particular need for an integral unit which combines cleanser application, scrubbing and drying for this kind of surface in one single trait.
DE 4125866 discloses a cleaning device which comprises a rubber blade for wiping and a vacuum suction nozzle for removing residual fluid or particles. This device, however, requires very strong suction power to retain used liquid inside the suction nozzle when the device is lowered and is not satisfactory. Practical experience shows that, unless the nozzle is always maintained in an upward position, dirty residual matter always drips and leaks out of the nozzle, causing inconvenience add nuisance to both the user and passers-by. For domestic users, dripping of dirty liquid on carpeted floors or upholstery can also be irritating.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a cleaning device which can combine cleaning, scrubbing and efficient residual matter removal in a single integral unit while overcoming the above-mentioned problems.
According to the present invention, there is therefore provided a cleaning device for use with a suction means comprising a head and neck portion, wherein a) said neck portion is in abutment with said head portion and connectible with a suction means; and b) said head portion comprises a base housing and a closure means, said base housing having an inlet edge, said inlet edge being normally in contiguous contact with said closure means, and said closure means being movable relative to said base housing and being normally urged against said inlet edge of said base housing, and being movable away from said inlet edge when pressed against surfaces to be cleaned.
Preferably the closure means comprises i) a rigid, non-absorbent closure plate attached to said base housing along one edge and another edge being movable relative to the housing at the inlet edge, and ii) a wiper blade which is flexible, non-absorbent and releasably attachable to the closure plate.
Preferably head portion of the device further comprises i) a top cover which is rigid and releasably attachable to the closure means, and ii) a wiper blade which is flexible and non-absorbent and sandwiched between the closure means and top cover.
Preferably the cleaning device further comprises scrubbing means having soft, absorbent material secured onto a rigid, non-absorbent attachment means which is releasably attachable from the device.
BRIEF DESCRIPTION OF THE DRAWINGS
A preferred embodiment of the present invention will now be explained by way of example and with reference to the accompanying drawings, in which:
FIG. 1 is an exploded view of a cleaning device embodying the present invention; and
FIG. 2 is a perspective view of a top cover for the device of FIG. 1 in the direction A--A;
FIG. 3 is a perspective view of a locking member for the device of FIG. 1 in the direction B--B; and
FIG. 4 is the cross-sectional view of the assembled cleaning device of FIG. 1.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIGS. 1 to 4, there is shown a cleaning device embodying the present invention comprising a neck 1 and a head 2 portion. The neck 1 comprises a generally tubular section for connection via a handle 3 to a vacuum suction means 4 which is also provided with a waste matter storage (not shown here). A nozzle 11 is mounted on the outside of the neck portion 1 by securing onto coupling means on a duct 12 which is formed on the inside of the neck portion 1. Pressurised cleansing solution supplied from a reservoir (not shown) to the duct is released from the nozzle 11 by a mechanical valve 31 controllable by a mechanical switch 32 on a detachable handle 3. The handle 3 also contains a length of duct 33 and is detachable to allow different possible extensions to be connected between the neck portion 1 and its top part to allow a large cleaning area coverage.
An elongated head 2, transverse to the axis of the neck 1, is formed at the top-end of the neck 1. The head 2 comprises a base housing 20, jaw 21, wiper blade 22, scrubbing means 23, top cover 24, and locking plate 25.
The elongated base housing 20 is made preferably of a hard and durable material such as plastics, it has a partly cylindrical shape with front inlet edge 201 curving upwards. Two sealing walls 202 extending vertically from the base housing 20 are formed at the two ends. Portions of the base housing 20 near the two ends are formed as convex surfaces, intersection of the convex surfaces with the concave base housing forms generally parabolic loci. Two vertical V-shaped sealing walls 203 are formed substantially along the parabolic intersection lines to provide further sealing.
The base housing 20 abuts the neck 1 near the middle, so that the device resembles the external appearance of a suction head for an ordinary vacuum cleaner. A plurality of hollow lugs 204, capable of screw engaging, are formed along a straight line near the rear edge 205. Another row of hollow lugs 206 are formed near the middle of the base housing 20 as part of the means for limiting maximum displacement of the jaw 21 relative to the base housing 20.
The jaw 21 is made preferably of a hard, resilient and non-permeable material, such as polypropylene or other hard plastic materials, and comprises a valve plate 211 which has a generally V-shaped cross-section and is receivable inside the space between the top cover 24 and the base housing 20. Near the rear edge 212, there are provided a plurality of through-holes 213, corresponding to the number of aforementioned hollow lugs 204 on the base housing 20, so that the jaw 21 can be affixed onto the base housing 20 with screws or other fasteners. Another row of through-holes 210 are formed at positions corresponding to the aforementioned lugs 206 so that displacement limiting means, such as large-headed screws, can be fastened onto the lugs through the holes 210 to limit maximum jaw 21 displacements. Formed near the front edge 214 is a slot 215 which is designed to accommodate the vertical limb 221 of a T-shaped wiper blade 22 inside and prevent dislocations thereof.
At a distance about half the blade width behind the slot 215, there is provided a vertical guard wall 216 which extends vertically from the upper surface of the jaw 21 and is designed to be just in contact with rear edge 222 of the wiper blade 22 so that horizontal displacement thereof beyond the wall 216 is prohibited. Behind the guard wall 216 and near the middle of the jaw 21 there are formed along the length a plurality of inverted L-shaped retaining means 217 for coupling with corresponding engaging means 25 1 formed on a slidable locking plate 25. Near the rear edge 212 of the jaw 21 there is provided a plurality of wall-liked protrusions 218 to allow scrubbing means 23 with attachment means to be releasably attached thereto. Thickness of the jaw 21 just before the rear edge 212 is reduced, forming a notch 219, and therefore a weakness, along the width. This notch 219 becomes a pivotal axis about which the front pan of the jaw 21 will be movable when its front part is forced to depart from the front inlet edge 201 of the base housing.
The wiper blade 22 has about the same length as the base housing 20, has a T-shaped cross section to prevent dislocation and is made of a generally flexible, resilient and non-absorbent material, such as silicon rubber, which would not cause scratching on delicate surfaces and is generally considered optimal for cleaning such surfaces. When the wiper blade 22 is properly placed inside the slot 2 15 and fixed in position, its vertical limb 221 extends beyond the slot 215 and is in contiguous contact with the front part of the base housing 20, forming a gate 221 which prevents transportation of matter in and out of the device unless gate 221 is opened.
The scrubbing means 23 is formed preferably by securing a soft and absorbent material 231 suitable for scrubbing, such as sponge, wool, cloth or other synthetic materials, onto a rigid frame 232 which is releasably attachable to the protruding walls 218 formed on the jaw 21. Preferably the frame 232 is also dimensioned with a shape complementary to the rear edge of the jaw 21 to improve sealing against liquid leakage.
A top cover 24, made preferably of the same material as the base housing 20, is designed to sandwich the wiper blade 22 tightly between it and the jaw 21. Such a cover also completes the head housing and therefore also serves to improve the air- and water-tightness. The top cover 24 is formed integrally with a rectangular trough 241 on the bottom of which there are provided a plurality of openings 243 just enough for passage of the aforementioned inverted L-shaped retaining means 217. Furthermore, area of the top cover 24 around the ends and front edge 242 of the trough opening is formed into a shallow indentation 244 to allow a locking plate 25 to sit in and slide on. To complete the construction, there is provided an inverted L-shaped locking plate 25 with a plurality of L-shaped engaging means 251 formed on the lower-side thereof. After the wiper blade 22 and the top cover 24 are put in place, the locking plate 25 is placed inside the aforementioned indentation 244, slightly depressed and slided to the left edge of the indentation 244 at which point the inverted L-shaped retaining means 217 interlock with the L-shaped engaging means 251, thereby securing the top cover 24 and wiper blade 22 together with the base housing 20. When the wiper blade 22 is pressed against a hard surface, front part 214 of the jaw 21 is forced to depart from the base housing 20, bringing with it a pivotal movement of the top cover 24 about the contact edge 245 with base from the inlet edge 201 of housing 20.
In operation, the cleaning device is connected to a vacuum suction means 4, such as a vacuum cleaner or vacuum pump, via the neck 1 and handle 3. Cleansing liquid supply duct 33 is connected to a reservoir from which cleansing liquid can be pressurised and continuously supplied to the surfaces through the nozzle 11. Surfaces thus wetted with cleansing liquid can be scrubbed thoroughly with the attached scrubbing means 23. The residual waste liquid, usually dirty and blended with pollutants, can be wiped by pressing and sliding the wiper blade 22 on the surface, the reactive force exerted on the jaw 21, through the wiper blade 22, by the surface causes the gate 221 to open and the proximity of the slit opening thus formed at the inlet edge 201 is therefore under the influence of suction means 4, residual fluid will therefore be sucked inside the device towards the suction means, thereby producing perfect cleaning with no leakage of dirty residual matter.
If the head 2 is not pressed against a hard surface, as in normal stand-by conditions, bias on the jaw 21 towards the base housing 20 always urges the gate 221 to close, thereby preventing waste matter leakage.
After prolonged repeated use, the wiper blade 22 may be worn out or hardened. Replacement can easily be done by firstly unlocking the locking plate, thereby releasing the top cover 24, and then inserting a new replacement wiper blade. The scrubbing means 23 can also be replaced in a similar manner.
While the present invention has been described with reference to a preferred embodiment, it will be appreciated that many other variations, modifications and applications of the invention may be made. | A cleaning head for use with suction means particularly suitable for cleaning hard, flat and smooth surfaces, such as glass or marble walls. The cleaning head is equipped with attachments for cleansing liquid application, scrubbing, wiping and waste liquid removal in one piece and is normally closed so that no waste liquid inside the head will leak out during quiescent operating condition. | 0 |
[0001] This is a continuation of international application No. PCT/US01/24554, filed Aug. 5, 2001, which is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] This invention relates to a carton and a blank for forming a carton which is used for accommodating one or more articles, for example, flexible pouch packs or bottles. It also concerns the method of forming the carton from the blank and loading the same with one or more articles. More particularly, the invention relates to a wraparound carton incorporating a top-gripping structure which attaches to an upper portion of one or more articles thereby to secure the articles in an array.
[0003] Top-gripping cartons are well known, particularly in the field of multiple packaging of bottles. One example is illustrated in U.S. Pat. No. 3,168,963 which illustrates a wraparound carton having an article-retaining structure and a retention panel between the top and bottom walls formed with at least one article receiving aperture.
[0004] A problem associated with known top-gripping carriers is that the retention panel and/or tubular structure for retaining the article will tend to collapse which creates an unstable carrier.
SUMMARY OF THE INVENTION
[0005] The present invention seeks to overcome or at least mitigate the problems of the prior art.
[0006] One aspect of the invention provides a carton for holding one or more articles, for example, flexible pouches. The carton comprises a sleeve body and an article-retaining structure for preventing the dislodgment of the packaged articles through the open ends of the sleeve body. The sleeve body comprises top and base walls interconnected by a pair of side walls. The article-retaining structure comprises a retention panel extending between the side walls intermediate the top and base walls to form a tubular structure in cooperation with the top wall. The retention panel is formed with at least one article-receiving aperture. The tubular structure is provided with a brace for retaining the tubular structure in an erected form.
[0007] According to an optional feature of this aspect of the invention the brace may comprises a brace panel hingedly connected to the retention panel and folded into the tubular structure to engage the inner side surface of the tubular structure. Optionally, the brace panel is struck from the retention panel and defines the article-receiving aperture when folded into the tubular structure.
[0008] According to another optional feature of this aspect of the invention the brace panel may be provided with a friction tab hingedly connected to the brace panel, the friction tab being adapted to engage the upper portion of one of the carton side walls. Alternatively, the brace panel may be provided with a friction tab hingedly connected to the brace panel, the friction tab being adapted to be pressed against the inner side surface of the tubular structure to retain the tab in the folded position.
[0009] Preferably, friction tab is struck from the side wall of the tubular structure.
[0010] According to a further optional feature of this aspect of the invention the side wall may comprises an upper side panel hingedly interconnecting the top wall and the retention panel and the lower side wall panel connecting the base wall and attached to the upper side wall panel and wherein said friction tab is struck from the upper side wall panel.
[0011] Preferably, the lower side panel is attached to the outer surface of the upper side panel to cover the opening defined in the upper side panel by the friction tab. More preferably, a portion of the friction tabs is revealed in the opening defined in the upper side panel and wherein the friction tab is secured by glue to the lower side panel.
[0012] According to another optional feature of this aspect of the invention wherein at least one opening is formed in either the top wall or in the side wall of the article-retaining structure to allow the top portion of one of the articles to be exposed to view.
[0013] There may further comprise an end closure structure for closing the ends of the carton, which end closure structure comprising an enclosure panel and at least one glue flap hingedly connected to the end closure panel to be secured to one of the base or side wall panels of the carton.
[0014] A second aspect of the invention provides a blank for forming a carton for holding one or more articles, for example, flexible pouches, which blank comprises a plurality of panels for forming a carton including a first side wall panel, a base panel, a second side wall panel and a top panel hingedly connected one to the next, and an article-retaining structure extending from the top panel comprising a retention panel and securing means to connect the retention panel to the side walls panels to form a tubular structure in a set up carton, the retention panel is formed with at least one article receiving aperture and a brace for retaining the tubular structure in an erected form.
[0015] The brace may comprise a brace panel hingedly connected to the retention panel and adapted to be folded into the tubular structure to engage the inner side surface of the tubular structure.
[0016] According to an optional feature of the second aspect of the invention the brace panel is struck from the retention panel and defines the article-receiving aperture when folded into the tubular structure.
[0017] According to a further optional feature of the second aspect of the invention, the brace panel is provided with a friction tab hingedly connected to the brace panel. Optionally, the tab is struck from the side wall panel.
[0018] According to another optional feature of the second aspect of the invention the side wall panel may comprise an upper side panel hingedly interconnecting the top wall panel and a lower side wall panel connected to the base wall and wherein said friction tab is struck from the upper side wall panel.
[0019] There may further comprise at least one opening is formed in either the top wall panel or in the side wall panel of the article-retaining structure to allow the top portion of one of the articles to be exposed to view in the set up carton.
[0020] According to a still further optional feature of the second aspect of the invention there further comprises an end closure structure for closing the ends of the carton, which end closure structure comprising an enclosure panel and at least one glue flap hingedly connected to the end closure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Exemplary embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:
[0022] [0022]FIG. 1 is a plan view of a blank of a first embodiment of the invention;
[0023] [0023]FIG. 2 is a plan view of a blank of a second embodiment of the invention;
[0024] [0024]FIG. 3 is a plan view of a blank of a third embodiment of the invention;
[0025] [0025]FIGS. 4 and 5 illustrate the first stages of construction of the first embodiment so that the carrier is in a flat collapsed condition ready to be supplied to an end user;
[0026] [0026]FIGS. 6, 7 and 8 illustrate the construction of the carrier from a flat collapsed condition illustrated in FIG. 5;
[0027] [0027]FIG. 9 illustrates the carrier shown in FIG. 5 in an erected and loaded condition;
[0028] [0028]FIG. 10 illustrates the carrier shown in FIG. 5 in a set-up and completed condition;
[0029] [0029]FIGS. 11 and 12 illustrate the construction of the carrier according to the third embodiment of the blank shown in FIG. 3;
[0030] [0030]FIG. 13 is a perspective view of the erected carton formed from the blank of FIG. 3; and
[0031] [0031]FIG. 14 is a fragmentary plan view of a blank of a fourth embodiment of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0032] Referring to the drawings, and in particular FIG. 1, there is shown a unitary blank 10 for forming an article carrier made from paperboard or similar foldable sheet material. In other embodiments, there may comprise a two-part blank, for example a blank for forming the wraparound carrier and a separate blank for forming the internal article-retaining structure. The blank 10 comprises a series of panels hingedly connected one to the next in series to define a top wall, opposed side walls and a base. Preferably, there comprises upper and lower side wall panels. Thus, the blank 10 comprises a plurality of panels for forming a wraparound carton, which in this embodiment comprises a first side wall panel 14 , a base panel 16 , second side wall panel 18 , an upper second side wall panel 20 and top wall panel 22 hingedly connected together in series along fold line 32 , 34 , 36 and 38 respectively.
[0033] In order to secure the first side wall panel 14 to the top panel 22 , suitable securing means is provided. In this embodiment, the securing means is provided by a securing flap 12 that is hingedly connected to the lateral edge of side panel 14 along fold line 30 .
[0034] There further comprises a plurality of panels for forming the article-retaining structure which are hingedly connected to the top panel 22 along fold line 40 . In this embodiment, the article-retaining structure is provided by a first spacer panel 24 , a retention panel 26 and a securing panel 28 hingedly connected together in series along fold lines 42 and 44 respectively. The spacer panel 24 spaces the retention panel 26 from the top panel 22 .
[0035] There may further comprise one or more display windows which are provided by apertures 46 , 48 struck from upper second side wall panel 20 that extend into top panel 22 , shown in FIG. 1. In use, the display apertures 46 , 48 reveal a portion of the cap of the article retained within the carrier.
[0036] A brace is provided to prevent the article-retaining structure from collapsing. In FIG. 1, there comprises a brace panel 50 struck from and hingedly connected to retention panel 26 along fold line 54 . Preferably, there further comprises a friction tab 58 struck from the adjacent spacer panel 24 and hingedly connected to bracing panel 50 along fold line 62 . In use, the bracing panel 50 is folded out of alignment with retention panel 26 to reveal an article receiving aperture 90 (FIG. 7). A second bracing panel may be provided which, in this embodiment, is designated by a reference numeral 52 and is struck from retention panel 26 and hingedly connected thereto along fold line 56 . Similarly, a friction tab 60 is hingedly connected to bracing panel 52 along fold line 64 .
[0037] Turning to the second embodiment illustrated in FIG. 2, the blank 110 is substantially the same as the first embodiment and like features are designated by the same reference numerals with the prefix “1”. Therefore, only the differences shall be described in any further detail.
[0038] An end closure structure is provided to prevent the articles from inadvertently being removed, for example, before the product has been sold. The end closure structures are provided by opposing end panels 176 a and 176 b hingedly connected to opposing sides of side wall panel 118 along fold lines 175 a and 175 b respectively. Suitable securing means is provided to secure the end closure panels 176 in place, for example a locking tab and aperture arrangement could be used.
[0039] The construction of each end closure structure is the same, so like reference numerals have been used in FIG. 2 with the addition of letter's ‘a’ and ‘b’ respectively. In this embodiment, glue flaps 178 and 180 are provided to be secured to the adjacent first side wall panel 114 and the base wall 116 respectively. It will be seen from FIG. 2 that glue flap 178 is secured to a longitudinal edge of end closure panel 176 along fold line 182 and that glue flap 180 is secured to a lateral edge of end closure panel 176 along fold line 184 , which in this embodiment is an extension of fold line 134 .
[0040] Turning to the third embodiment illustrated in FIG. 3, it is similar to the first embodiment in its overall construction; and it is similar to the second embodiment in that there are provided end closure panels 276 . Like features of the first and second embodiments are designated by the same reference numeral with the prefix “2”. Therefore, only those differences between the second and third embodiments are described in any further detail.
[0041] In the third embodiment, there further comprises an additional aperture 270 along the opposing part of top panel 220 which is aligned with the corresponding aperture 246 . Aperture 270 is struck from top panel 220 and extends into spacer panel 224 . In use, aperture 270 provides a second display window for the upper portion of the adjacent article A. Likewise, in those embodiments with two rows of articles, a second aperture 272 struck from top panel 220 and extending spacer panel 224 is provided to be substantially aligned with aperture 248 .
[0042] There are also corresponding recesses 286 , 288 along the free edge of side panel 214 . In use, the recesses 286 and 288 are aligned with aperture 270 and 272 respectively to provide a display window.
[0043] In one class of embodiments, the friction tab 258 is not co-extensive with bracing panel 250 and terminates short, so that an aperture or notch 266 is provided. In use, the notch 266 functions to allow the tab 258 to protrude through the opening 270 to be engaged with an article. There is a similar notch 268 provided adjacent to bracing tab 260 that functions in the same way.
[0044] There may further comprise an aperture 274 struck from one of the side panels and a corresponding recess portion 289 in glue flap 228 to provide an additional display window to reveal part of the side wall of an article A.
[0045] Turning to the fourth embodiment illustrated in FIG. 14, it is virtually identical to the third embodiment in its overall construction except for the details of the friction tabs. Like features of the third embodiment are designated by the same reference numeral with the prefix “3”. Therefore, only those differences between the third and fourth embodiments are described in any further detail.
[0046] In the fourth embodiment, the friction tab 358 , again, is not co-extensive with bracing panel 350 and terminates short. However, an aperture or notch 366 is defined adjacent to the free end edge of the bracing panel 350 remote from fold line 354 . In use, the notch 366 functions to prevent the tab 358 from being exposed to view through opening 370 . In other words, the notch 366 is struck from the friction tab 358 to cooperate with the opening 370 to provide a window to reveal the top portion of one of the articles. There is a similar notch 368 provided adjacent to the free end edge of bracing panel 352 . The notch 368 functions to prevent friction tab 360 from being exposed to view through opening 372 .
[0047] Turning to the construction of the carton formed from one of the blanks illustrated in FIGS. 1, 2, 3 or 14 , it is envisaged that the carton of the present invention can be formed by a series of sequential folding and gluing operations which can be performed in a straight line machine, so that the carton is not required to be rotated or converted to complete its construction. The folding process is not limited to that described below and can be altered according to particular manufacturing requirements.
[0048] Turning now in particular to FIG. 4, the blank 10 of the first embodiment is folded in direction X along fold line 40 to form the internal article-retaining structure. Thus, spacer panel 24 and retention panel 26 are placed in face-contacting relationship with top panel 22 and upper second side wall panel 20 and are held in place by securing flap 28 to side wall panel 18 by glue G or other suitable securing means known in the art. The carrier is at an intermediate stage construction, shown in FIG. 5, whereby it is in flat collapsed condition ready to be supplied to a user, for example a bottler, to be loaded with articles, described below.
[0049] In order to construct and load the carrier, the retaining structure and brace are formed, whereby panels 20 , 22 , 24 and 26 forming the article-retaining structure are folded along fold lines 38 , 40 , 42 and 44 in direction Y so as to form a tubular structure T as shown in FIG. 6. This folding action reveals friction tabs 58 and 60 that are ready to form the brace. Thereafter, the brace is formed by folding brace panels 50 and 52 in directions W and V respectively along fold lines 54 and 56 as shown in FIG. 7 to take up a bracing position. The bracing panels 50 , 52 act as braces by their free edges coming into contact with opposed spacer panels 24 , 28 or, as the case may be, side walls. Additionally, or alternatively, the bracing tabs may abut the top wall to provide a brace between the top and retention panels 22 , 26 .
[0050] In those embodiments with friction tabs 58 and 60 are folded along fold lines 62 and 64 , so as to come into face contacting relationship with spacer panel 24 . It is envisaged that in some embodiments the spacer panels are dispensed with, in which case the friction tabs come into face contacting relationship with the side walls.
[0051] Turning again to the embodiment shown in FIG. 7, the brace panels 50 , 52 are held in place by the frictional engagement between the inner face of spacer panel 24 and the tabs 58 and 60 respectively, thereby to maintain the tubular structure in a set-up condition. Optionally, glue may be applied to friction tabs 58 , 60 so that they are secured to spacer panel 24 . The tabs 58 , 60 may be shaped so as to protrude in part 59 , 61 (FIG. 9), through apertures 90 , 92 . Beneficially, this allows tabs 58 , 60 to be secured directly to an outer panel of the carrier, for example, securing tab 12 to provide a structure of improved rigidity.
[0052] In order to complete construction of the carton, the panels forming the wraparound carrier are formed, so that the base panel 16 and first side wall panel 14 are folded out of alignment with second side wall panel 18 along fold lines 34 and 32 respectively as shown in FIG. 8.
[0053] Prior to constructing the wraparound carrier, the articles are applied to the carrier by relative movement between the article A and the tubular structure T, preferably during continuous forward movement. The articles are grouped in a two-by-two array although is anticipated that other groupings or even a single article could be packaged without departing from the scope of the invention.
[0054] As shown in FIGS. 9 and 10 the articles pass through apertures 90 and 92 to be held in place within the tubular structure T. In some embodiments, suitable retention means engage the upper part of the article(s) to prevent any movement within the apertures 90 , 92 . Thereafter, the side and base walls are folded as described above and the first side wall panel 14 is secured to the article-retaining structure by securing glue flap 12 to spacer panel 24 by glue or other suitable means known in the art. Thus, the carton is in set-up and loaded condition as shown in FIG. 10.
[0055] It will be seen that the articles to be packaged, in this embodiment, are flexible foil pouches and so, in order to retain the articles in place, the panels forming the wraparound carrier are drawn in tightly by moving the securing flap 12 up along spacer panel 24 prior to being secured therewith so as to provide a stable and easy stacking package.
[0056] The construction of the second, third and fourth embodiments are substantially the same as the first embodiment described and illustrated in FIGS. 4, 5, 6 and 7 and, therefore, only the construction of the end closure structure is described in any greater detail. The articles A are applied to the article-retaining structure by relative vertical movement during continuous forward feed, as shown in FIGS. 11 and 12, and before folding the base and side wall panels 216 , 214 , the end closure structure is formed. This is achieved by folding end wall panel 276 inwardly along fold line 275 . In addition, glue flaps 278 and 280 are folded along fold lines 282 and 284 respectively around the articles A, as illustrated in FIG. 12. Thereafter, the base and/or first side wall panel 214 may be secured to the glue flaps 278 and/or 280 respectively to retain the end closure panels 276 in place. Thus, the carton is in a set-up condition as shown in FIG. 13.
[0057] In the embodiment shown in FIG. 12, the friction tabs 258 and 260 are engaged in apertures 270 and 272 respectively, to retain the brace panels 250 and 252 in a bracing position.
[0058] The present invention and its preferred embodiments relate to an arrangement for forming a brace in an article-retaining structure formed from material that also forms one or more article receiving apertures. However, it is anticipated that the invention can be applied to a variety of carriers and not limited to those of a wraparound type described above.
[0059] It will be recognized that as used herein, directional references such as “top”, “base”, “end”, “side”, “inner”, “outer”, “upper” and “lower” do not limit the respective panels to such orientation, but merely serve to distinguish these panels from one another. Any reference to “hinged connection” or fold line should not be constructed as necessarily referring to a single fold line only; indeed, it is envisaged that “hinged connection” can be formed from one or more the following, score line, a frangible line or a fold line, without departing from the scope of the invention.
[0060] It should be understood that various changes can be made within the scope of the present invention. For example, the size and shape of the panels and apertures may be adjusted to accommodate articles of different size or shape, alternatively top and base closure structures may be used. The carton may accommodate more than one article in different arrays. In the illustrated embodiment, there comprise four articles arranged in two-by-two array although, of course, other arrays are envisaged. | A carton and blank for forming a carton for holding one or more articles, for example, flexible pouches, which carton comprises an article-retaining structure for preventing the dislodgment of the packaged articles through the open ends of the carton. The article-retaining structure comprises a retention panel extends between the carton side walls intermediate the top and base walls of the carton to form a tubular structure in cooperation with the top wall. The retention panel is formed with at least one article receiving aperture, wherein tubular structure is provided with a brace for retaining the tubular structure in an erected form. | 1 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The following patent applications, all of which were filed on the same day as this patent application, are hereby incorporated by reference into this patent application as if set forth herein in full: (1) U.S. patent application Ser. No. ______, entitled “Injection Molded PTC-Ceramics”, Attorney Docket No. 14219-186001, Application Ref. P2007,1179USE; (2) U.S. patent application Ser. No. ______, entitled “Feedstock And Method For Preparing The Feedstock”, Attorney Docket No. 14219-187001, Application Ref. P2007,1180USE; (3) U.S. patent application Ser. No. ______, entitled “Process For Heating A Fluid And An Injection Molded Molding”, Attorney Docket No. 14219-182001, Application Ref. P2007,1182USE; (4) U.S. patent application Ser. No. ______, entitled “Injection Molded Nozzle And Injector And Injector Comprising The Injection Molded Nozzle”, Attorney Docket No. 14219-183001, Application Ref. P2007,1183USE; and (5) U.S. patent application Ser. No. ______, entitled “PTC-Resistor”, Attorney Docket No. 14219-185001, Application Ref. P2007,1184USE.
TECHNICAL FIELD
[0002] This disclosure relates to fuel injector systems for combustion engines, in particular to heaters for fuels.
BACKGROUND
[0003] There is a need for providing fuel at an appropriate temperature in an engine that is still cold. This problem occurs especially when the fuel contains methanol or ethanol as a main component. In this case, may be difficult to spray the fuel in an appropriate way when the outer temperatures are low and the engine is not located in a heated housing such as the engine of an automobile. If the fuel is not at the minimum temperature and the spray of the fuel is not sufficiently fine, the result is an insufficient mixing of fuel and air in the combustion chamber.
SUMMARY
[0004] A heating system for fluids in the form of a mold comprising a ceramic with a positive temperature coefficient, a so called PTC-ceramic, is described. The ceramic may for example be based on Bariumtitanate (BaTiO 3 ), which is a ceramic of the perovskite-type (ABO 3 ). The ceramic can be doped for example in the view of the Curie-temperature T C , which for example can be chosen on her part in view of the boiling point of the liquid, which should be heated. A doping of the BaTiO 3 ceramic with Sr decreases the Curie-temperature, whereas a doping with Pb increases the Curie-temperature. Additionally TiO 2 and SiO 2 can be added to the ceramic.
[0005] The heating system can be injection molded out of the PTC-ceramic. A fluid to be heated is heated via the heating system as it flows through the mold. The heating system may be located next to a nozzle that ejects it.
[0006] By preheating a fuel before it reaches a nozzle, a finer quality of spray ejected from the nozzle is obtainable. In view of this, the temperature may be controlled in consideration of the boiling point of the fuel or its spraying temperature. The PTC-ceramic and the voltage applied to the mold may be chosen under this aspect.
[0007] The PTC-ceramic comprises a self regulative property. If the temperature of the heating system reaches a critical level, the resistance of the PTC ceramic also rises and thus reduces the electric current running through it. As a result, the PTC ceramic of the mold ceases to heat and is allowed to cool. Thus, no external regulation system is necessary if the PTC-ceramic material is chosen under the view of the fluid respectively to the temperature, which the fluid should reach maximum. This also means that the system regulates itself back, when heat additionally comes from the engine such as when it has been running for a while.
[0008] The heating system responds rapidly for two main reasons: firstly, it warms quickly and secondly, the heat is rapidly transferable to the fluid due to the latter's direct contact with the mold. The direct contact with the mold enables a fast and efficient transfer of the energy to the fluid compared to systems where a heating system is located around a channel or a tube in which the fluid is running.
[0009] In order to increase the rate of heat transfer, the inner surface of the mold may be enlarged by providing it with geometric moldings.
[0010] To achieve a high degree heat transfer between the molding an a fluid passing through the fluid channel, the fluid may flow at a moderate speed in at least one part of the heating system. The cross section of the fluid channel therefore may vary. A larger cross section on the inlet side and a smaller cross section at the outlet side of the fluid channel makes it possible to have a slower flow rate of the fluid in a first part of the mold in order to obtain a high degree of heat transfer a higher flow rate at the end of the heating system. The latter may be preferable for a spraying process. It thus may be preferred to reduce the cross section of the fluid channel in at least one subsection of the mold. Shapes and forms conducive to this goal are obtainable by injection molding.
[0011] For the injection molding process a feedstock could be used comprising a ceramic filler, a matrix for binding the filler and a content of less than 10 ppm of metallic impurities. One possible ceramic filler can be denoted by the structure:
[0000] Ba 1-x-y M x D y Ti 1-a-b N a Mn b O 3
[0000] wherein the parameters are x=0 to 0.5, y=0 to 0.01, a=0 to 0.01 and b=0 to 0.01. In this structure M stands for a cation of the valency two, like for example Ca, Sr or Pb, D stands for a donor of the valency three or four, for example Y, La or rare earth elements, and N stands for a cation of the valency five or six, for example Nb or Sb. Thus, a high variety of ceramic materials can be used wherein the composition of the ceramic may be chosen in dependency of the required electrical features of the later sintered ceramic. The ceramic filler of the feedstock is convertible to a PTC-ceramic with low resistivity and a steep slope of the resistance-temperature curve. The resistivity of a PTC-ceramic made of such a feedstock can comprise a range from 3 Ωcm to 30000 Ωcm at 25° C. in dependence of the composition of the ceramic filler and the conditions during sintering the feedstock. The characteristic temperature T b at which the resistance begins to increase comprises a range of −30° C. to 340° C. As higher amounts of impurities could impede the electrical features of the molded PTC-ceramic the content of the metallic impurities in the feedstock is lower than 10 ppm.
[0012] The metallic impurities in the feedstock may comprise Fe, Al, Ni, Cr and W. Their content in the feedstock, in combination with one another or each respectively, is less than 10 ppm due to abrasion from tools employed during the preparation of the feedstock.
[0013] A method for preparing a feedstock for injection molding is described, comprising the steps A) preparing a ceramic filler being convertible to PTC-ceramic by sintering, B) mixing the ceramic filler with a matrix for binding the filler, and C) producing a granulate comprising the filler and the matrix.
[0014] The method comprises using tools having such a low degree of abrasion that a feedstock comprising less than 10 ppm of impurities caused by said abrasion is prepared. Thus, preparation of injection moldable feedstocks with a low amount of abrasion caused metallic impurities is achieved without the loss of desired electrical features of the molded PTC-ceramic.
[0015] In step A) base materials of the filler can be mixed, calcinated and ground to a powder. During the calcination which can be performed at temperatures of about 1100° C. for around two hours a ceramic material of the structure Ba 1-x-y M x D y Ti 1-a-b N a Mn b O 3 with x=0 to 0.5, y=0 to 0.01, a=0 to 0.01 and b=0 to 0.01 is formed, where M stand for a cation of the valency two, D a donor of the valency three or four, for example Y, La or rare earth elements, and N a cation of the valency five or six, for example Nb or Sb. This ceramic material is ground to a powder and dried to obtain the ceramic filler.
[0016] As base materials, BaCO 3 , TiO 2 , Mn- and Y-ion containing solutions and at least one out of the group of SiO 2 , CaCO 3 , SrCO 3 , Pb 3 O 4 may be used to prepare the ceramic filler. From these base materials a ceramic material of a composition such as (Ba 0.3290 Ca 0.0505 Sr 0.0969 Pb 0.1306 Y 0.005 ) (Ti 0.502 Mn 0.0007 )O 1.5045 can be prepared, for example. A sintered body of this ceramic material has a characteristic reference temperature T b of 122° C. and—depending on the conditions during sintering—a resistivity range from 40 to 200 Ωcm.
[0017] According to an implementation of the method, step B) is performed at a temperature of 100° C. to 200° C. First, the ceramic filler and the matrix are mixed at room temperature, after which this cold mixture is put into a hot mixer which is heated to temperatures of 100° C. to 200° C., e.g., between 120° C. to 170° C., for example 1600 C. The ceramic filler and the matrix which binds the filler are kneaded in the hot mixer to homogenous consistency at elevated temperatures. As a mixer or mixing device, a twin-roll mill or other kneading/crushing device may be used.
[0018] A twin-roll mill may include two counter-rotating differential speed rollers with an adjustable nip and imposes intense shear stresses on the ceramic filler and the matrix as they pass through the nip. Further, a single-screw or a twin-screw extruder as well as a ball mill or a blade-type mixer may be used for preparing the mixture containing the matrix and the ceramic filler.
[0019] In step C), the mixture of matrix and ceramic filler can be cooled to room temperature and reduced to small pieces. The mixture hardens when it is cooled and by reducing it to small pieces a granulate of feedstock material is formed.
[0020] According to an implementation of the method, the tools used in method steps A), B) and C) comprise coatings of a hard material. The coating may comprise any hard metal, such as, for example, tungsten carbide (WC). Such a coating reduces the degree of abrasion of the tools when in contact with the mixture of ceramic filler and matrix and enables the preparation of a feedstock with a low amount of metallic impurities caused by said abrasion. Metallic impurities may be Fe, but also Al, Ni or Cr. When the tools are coated with a hard coating such as WC, impurities of W may be introduced into the feedstock. However, these impurities have a content of less than 50 ppm. It was found that in this concentration, they do not influence the desired electrical features of the sintered PTC-ceramic.
[0021] Where injection molding is used to form the mold, care must be taken regarding the metallic impurities in the mold to ensure that the efficiency of the PTC-ceramic is not reduced. The PTC-effect of ceramic materials comprises a change of the electric resistivity ρ as a function of the temperature T. While in a certain temperature range the change of the resistivity ρ is small with a rise of the temperature T, starting at the so-called Curie-temperature T C the resistivity ρ rapidly increases with a rise of temperature. In this second temperature range, the temperature coefficient, which is the relative change of the resistivity at a given temperature, can be in a range of 50%/K up to 100%/K. If there is no rapidly increase at the Curie-temperature the self regulating property of the mold is unsatisfactory.
[0022] In order to obtain a desirable efficiency of the mold, the entire mold may be suited to transferring heat to the fluid. Thus, an electric current may flow through the entire or nearly the entire mass of the mold. Therefore, the entire or nearly the entire surface of the inner and outer side of the mold is provided with electrical contacts. According to one embodiment of the mold, it is provided with electrically conductive layers on its inner an outer surface.
[0023] The inner side of the mold additionally comprises, according to one embodiment, a passivation layer to prevent interactions, such as chemical reactions, between the fluid and the PTC-ceramic or the electric contact layer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] A number of embodiments are shown in the following drawings. The illustrations of the embodiments are schematic.
[0025] FIG. 1 shows a section of an embodiment of a mold comprising a PTC ceramic,
[0026] FIGS. 2 a to 2 c show a preheating process of a liquid in an embodiment according to FIG. 1 ,
[0027] FIG. 3 shows an embodiment with a non-cylindrical form and more than one fluid outlet,
[0028] FIG. 4 shows a schematic view inside a embodiment with a plurality of fluid channels.
DETAILED DESCRIPTION
[0029] FIG. 1 depicts a mold 1 with a fluid channel 2 , a fluid inlet 3 and a fluid outlet 4 . The mold can be subdivided into three subsections: a first subsection 10 at the fluid inlet 3 , a second subsection 20 at the fluid outlet 4 , and one subsection 15 between the first and the second. In this embodiment the cross section of the first subsection 10 is larger than the cross section of the second subsection 20 and the fluid inlet 3 is larger than the fluid outlet 4 . So the speed of a fluid flowing through the fluid channel 2 is lower in the first subsection, thereby improving heat transfer from the mold to the fluid.
[0030] The inner surface of the first subsection 10 is enlarged by geometric protrusions 5 . In this embodiment the geometric protrusions 5 are molded as ribs. The larger inner surface of the mold 1 makes the heating system more efficient, since the heat can be transferred more rapidly from the mold to the fluid flowing through it. The ribs can be helical such that the fluid flowing through the fluid channel 2 is made to rotate around the axis of the flow.
[0031] The mold 1 is injection molded from a PTC-ceramic with the following composition: ABO 3 +SiO 2 , whereby A is composed of Ba 83.54 mol %, Ca 13.5 mol %, Sr 2.5 mol %, Y 0.4 mol % and B is composed of Ti 99.94 mol %, Mn 0.06 mol %. The part of Si is 2 mol % relating to the sum of both components. This composition can for example be used for a preheating system for ethanol. The concentration of any metallic impurity is lower than 10 ppm.
[0032] The mold 1 is provided with an electrically conductive layer on its inner and outer surface. The inner surface is additionally provided with a passivation layer 6 . This passivation layer 6 can for example comprise low melting glass or nano-composite lacquer. The nano-composite lacquer can comprise one or more of the following composites: SiO 2 -polyacrylate-composite, SiO 2 -polyether-composite, SiO 2 -silicone-composite.
[0033] FIGS. 2 a to 2 c show the preheating process of a liquid in an embodiment of a mold according to FIG. 1 . Three cross sections of the middle of the subsection 20 (left) and the middle of the subsection 10 (right) are shown. The subsection 20 has a constant outer diameter of 2.5 mm and a constant inner diameter of 1 mm. The subsection 10 has a constant outer diameter of 6 mm and a constant inner diameter of 4.5 mm without the ribs.
[0034] The preheating process starts with a liquid at a temperature of −40° C., and a temperature of the mold 1 of 105° C. ( 100 ). FIG. 2 a shows the preheating process after 2 seconds, FIG. 2 b after 5 seconds, and FIG. 2 c after 10 seconds. Already after 2 seconds ( FIG. 2 a ), the liquid between the ribs ( 5 ) has a temperature of minimum 500 C ( 110 ). The temperature of the liquid in the centre of the middle of the subsection 10 is still at −35° C. ( 120 ). After 5 seconds ( FIG. 2 b ), the fluid in the centre of the middle of the subsection 20 has approximately reached the temperature of the mold itself, 105° C. ( 100 ). After 10 seconds ( FIG. 2 c ), the fluid between the ribs ( 5 ) in the middle of the subsection 10 has also reached the temperature of 105° C. ( 100 ).
[0035] FIG. 3 shows a further embodiment comprising more than one fluid inlet 3 and more than one fluid outlet 4 . The mold has a non cylindrical form and nine fluid inlets 3 and nine fluid outlets 4 . The advantage of an embodiment form like this is that a large volume of fluid can be heated in a small device. This embodiment could be used for truck engines which high fuel consumption.
[0036] FIG. 4 schematically shows the view inside a non-cylindrically formed mold with a plurality of fluid channels 2 , in particular with four fluid channels. Here the fluid channels 2 narrows over the entire length of the mold 1 .
[0037] The mold 1 can be used for example in an arrangement with a nozzle. Such an arrangement can be used to preheat fuel in combusting engines. The preheated fuel assures a good spray effect in a few seconds because of its heating efficiency despite the fuel having a low temperature before it entering the preheating system. Thus, such an arrangement is in particular useful for the cold start of an engine using ethanol or methanol as fuel. Arranging the mold 1 close to the nozzle ensures that the fluid reaches the spraying end of the nozzle at the desired temperature. In the case of ethanol, this temperature has to be above 13° C. to obtain a satisfying spray result. In some cases the spray result could be improved if the fluid reaches the nozzle with a rotation around the axis of the flow. So the inner surface of the mold 1 can be formed in a manner such that the fluid is made to rotate like this.
[0038] The mold 1 may include an element of an arrangement further comprising a valve and a nozzle. The fuel is preheated by the mold 1 before it is dosed by the valve into the nozzle out of which the fuel is then sprayed.
[0039] Other implementations are within the scope of the following claims. Elements of different implementations, including elements from applications incorporated herein by reference, may be combined to form implementations not specifically described herein. | A mold includes a fluid channel, a fluid inlet, and a fluid outlet. The mold is manufactured, at least in part, from a PTC-ceramic material. Upon application of a voltage to the mold, the mold is heated such that a fluid passing through the fluid channel may also be subject to heating. | 8 |
CROSS-REFERENCES TO RELATED APPLICATION
[0001] The present application claims priority under 35 U.S.C. §119(a) to Korean application number 10-2013-0046090, filed on Apr. 25, 2013, in the Korean Intellectual Property Office, which is incorporated herein by reference in its entirety.
BACKGROUND
[0002] Currently, resistive memory devices using a resistance material has been suggested, and the resistive memory devices may include phase-change random access memories (PCRAMs), resistance RAMs (ReRAMs), or magentoresistive RAMs (MRAMs) has been suggested.
[0003] The resistive memory devices may include a switching device and a resistance device, and may store data “0” or “1” according to a state of the resistance device.
[0004] Even in the resistive memory devices the first priority is to improve integration density and to integrate memory cells in a narrow area as many as possible.
[0005] Currently, the variable resistance memory device is also configured in a 3D structure, but there is a high need for a method of stably stacking a plurality of memory cells with smaller critical dimension (CD).
SUMMARY
[0006] An exemplary variable resistance memory device. The variable resistance memory device may include: a semiconductor substrate; a common source region formed on the semiconductor layer; a channel layer formed substantially perpendicular to a surface of the semiconductor substrate, the channel layer being selectively connected to the common source region; a plurality of cell gate electrodes formed along a side of the channel layer; a gate insulating layer formed around each cell gate electrode, of the plurality of cell gate electrodes, a cell drain region located between the each cell gate electrode of the plurality of cell gate electrodes; a variable resistance layer formed along another side of the channel layer; and a bit line electrically connected to the channel layer and the variable resistance layer.
[0007] An exemplary method of manufacturing a variable resistance memory device include: forming a common source line on a semiconductor substrate; forming selection switches on the common source region; forming, over the selection switches, an insulating structure on the semiconductor substrate by alternately stacking a plurality of first interlayer insulating layers, having a first etch selectivity, and a plurality of second interlayer insulating layers, having a second etch selectivity that is different than the first etch selectivity; forming through-holes in the insulating structure to expose the string selection switches; forming space portions by removing portions of the plurality of first interlayer insulating layers exposed through the through-holes; forming a cell drain region in each of the space portions; forming, in each through-hole, a channel layer along surfaces defining each through-hole; selectively removing the plurality of second insulating layers to form a plurality of openings; forming a gate insulating layer in each opening of the plurality of openings; forming a cell gate electrode in each opening, of the plurality of openings, so that each cell gate electrode is surrounded by a gate insulating layer; forming a variable resistance layer on a surface of the channel layer; forming an insulating layer in the through-holes; and forming a bit line to be electrically connected to the channel layer and the variable resistance layer.
[0008] An exemplary variable resistance memory device may include: a plurality of cell gate electrodes extending in a first direction, wherein the plurality of cell gate electrodes are stacked in a second direction that is substantially perpendicular to the first direction; a gate insulating layer surrounding each cell gate electrode of the plurality of cell gate electrodes; a cell drain region formed on two sides of the each cell gate electrode of the plurality of cell gate electrodes; a channel layer extending in the second direction along the stack of the plurality of cell gate electrodes; and a variable resistance layer contacting the channel layer.
[0009] A method of operating an exemplary variable resistance memory device, including a plurality of memory cells having a plurality of cell gate electrodes extending in a first direction, wherein the plurality of cell gate electrodes are stacked in a second direction that is substantially perpendicular to the first direction; a gate insulating layer surrounding each cell gate electrode of the plurality of cell gate electrodes; a cell drain region formed on two sides of the each cell gate electrode of the plurality of cell gate electrodes; a channel layer extending in the second direction along the stack of the plurality of cell gate electrodes; and a variable resistance layer contacting the channel layer, wherein the variable resistance memory device is in contact with a selection switch, may include: selecting a memory cell, of the plurality of memory cells, via the selection switch; passing a current from a bit line through a variable resistor of the selected memory cell to perform an operation on the selected memory cell; and passing the current through a portion of the channel layer associated with a non-selected memory cell.
[0010] These and other features, aspects, and exemplary implementations are described below in the section entitled “DETAILED DESCRIPTION”.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The above and other aspects, features and other advantages of the subject matter of the present disclosure will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:
[0012] FIG. 1 is a circuit diagram illustrating an exemplary variable resistance memory device;
[0013] FIG. 2 is a circuit diagram illustrating an exemplary variable resistance;
[0014] FIG. 3 is a view illustrating a driving method of an variable resistance memory device;
[0015] FIGS. 4 to 10 are cross-sectional views sequentially illustrating an exemplary method of manufacturing a variable resistance memory device;
[0016] FIG. 11 is an enlarged view illustrating an exemplary switching device of a variable resistance memory device; and
[0017] FIGS. 12 and 13 are cross-sectional views illustrating exemplary variable resistance memory devices.
DETAILED DESCRIPTION
[0018] Hereinafter, exemplary implementations will be described in greater detail with reference to the accompanying drawings.
[0019] Exemplary implementations are described herein with reference to cross-sectional illustrations that are schematic illustrations of exemplary implementations (and intermediate structures). As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, exemplary implementations should not be construed as limited to the particular shapes of regions illustrated herein but may be to include deviations in shapes that result, for example, from manufacturing. In the drawings, lengths and sizes of layers and regions may be exaggerated for clarity. Throughout the disclosure, reference numerals correspond directly to the like numbered parts in the various figures and implementations of the present invention. It should be readily understood that the meaning of “on” and “over” in the present disclosure should be interpreted in the broadest manner such that “on” means not only “directly on” but also “on” something with an intermediate feature(s) or a layer(s) therebetween, and that “over” means not only directly on top but also on top of something with an intermediate feature(s) or a layer(s) therebetween
[0020] Referring to FIG. 1 , an exemplary variable resistance memory device 10 includes a plurality of memory cells mc 1 , mc 2 , mc 3 , and mc 4 , connected in series.
[0021] The plurality of memory cells mc 1 , mc 2 , mc 3 , and mc 4 , which are connected in series, may be connected between a bit line BL and a common source line CS. That is, the plurality of memory cells mc 1 , mc 2 , mc 3 , and mc 4 may be implemented by sequentially stacking the memory cells mc 1 , mc 2 , mc 3 , and rnc 4 on a semiconductor substrate (not shown). In the exemplary implementation, a set of the stacked memory cells mc 1 to mc 4 , connected in series, may be referred to as a column string SS 1 and SS 2 . A plurality of column strings SS 1 and SS 2 may be connected to one bit line BL.
[0022] Each of the plurality of memory cells mc 1 to mc 4 may include a switching device SW 1 to SW 4 and a variable resistor R 1 to R 4 . The switching device SW 1 to SW 4 and the variable resistor R 1 to R 4 may be connected in parallel to each other.
[0023] A MOS transistor, a diode, a bipolar transistor, or an impact ionization MOS (IMOS) transistor may be used as the switching devices SW 1 to SW 4 . The variable resistors R 1 to R 4 may include various materials, such as a Pr1-xCaxMnO3 (PCMO) layer, if the variable resistor is a ReRAM, a chalcogenide layer, if the variable resistor is a PCRAM, a magnetic layer, if the variable resistor is a MRAM, a magnetization reversal device layer, if the variable resistor is a spin-transfer torque magnetoresistive RAM (STTMRAM), or a polymer layer, if the variable resistor is a polymer RAM (PoRAM).
[0024] A column switch array 15 may be connected between the column strings SS 1 and SS 2 and the common source line CS. The column switch array 15 may include a plurality of string selection switches SSW 1 and SSW 2 . Each of the string selection switches SSW 1 and SSW 2 may be connected to a corresponding column strings SS 1 or SS 2 . Each of the string selection switches SSW 1 or SSW 2 selectively connects a corresponding column string SS 1 or SS 2 to the common source line CS in response to a corresponding selection signal a 1 or a 2 .
[0025] FIG. 2 illustrates an alternative arrangement of the column switch array 15 , the column strings SS 1 and SS 2 , and the bit line BL.
[0026] Hereinafter, driving the exemplary variable resistance memory device will be described. As an example, a process of reading and writing data from and to a third memory cell mc 3 of a first column string SS 1 will be described.
[0027] Referring to 3 , a high voltage is applied to a gate a 1 of a first string switch SSW 1 to select the first column string SS 1 .
[0028] To write data to the third memory cell mc 3 , the switching device SW 3 of the third memory cell mc 3 is turned off, and the first switching device SW 1 of the first memory cell mc 1 , the second switching device SW 2 of second memory cell mc 2 , and the fourth switching device SW 4 of the fourth memory cells mc 4 , are turned on.
[0029] Accordingly, the fourth switching device SW 4 in the fourth memory cell mc 4 , the second switching device SW 2 in the second memory cell mc 2 , and the first switching device SW 1 in the first memory cell mc 1 , are turned on to form a current path is formed in the fourth switching device SW 4 , the second switching device SW 2 , and the first switching device SW 1 . The third switching device SW 3 in the third memory cell mc 3 is turned off, and a current path is formed in a third variable resistor R 3 .
[0030] Therefore, a write current Iw, provided from the bit line BL, flows to the common source line CS through the fourth switching device SW 4 , the third variable resistor R 3 , and the second switching device SW 2 , and first switching device SW 1 . Therefore, data may be written to the third memory cell mc 3 .
[0031] A read operation of the third memory cell mc 3 may be carried out in substantially the same manner as described above for the write operation, except that a read current Ir (instead of a write current Iw) may be provided from the bit line BL. The read current Ir reaches the common source line CS connected to a ground through a corresponding current path. The data written in the variable resistor R 3 may be sensed by measuring using read circuit (not shown) a current value reaching the common source line CS. At this time, the read current Ir has a level that does not affect a crystallization state of the variable resistor R 3 , and may have a lower value than that of the write current Iw.
[0032] Hereinafter, a exemplary method of manufacturing an exemplary variable resistance memory device will be described with reference to FIGS. 4 to 10 .
[0033] Referring to FIG. 4 , a common source region 105 is formed on a semiconductor substrate 100 . In FIG. 4 , an “X” region indicates a portion of the variable resistance memory device taken in a direction parallel to a bit line to be formed later, and a “Y” region indicates a portion of the variable resistance memory device taken in a direction perpendicular to the bit line. The common source region 105 may be configured of, for example, an impurity region or a conductive layer. A conductivity type of the common source region 105 may be determined according to a conductivity type of the string selection switches SSW 1 and SSW 2 . For example, if the string selection switches SSW 1 and SSW 2 are an MOS transistor, then the common source region 105 may be an N-type impurity region or a polysilicon layer doped with an N-type impurity.
[0034] A conductive layer having a certain thickness may be formed on the common source region 105 , and then patterned to form a plurality of pillars 110 that will form channels of the string selection switches SSW 1 and SSW 2 . The pillars 110 may include semiconductor layers, such as polysilicon layers. A drain region 115 may be formed into an upper portion of each of the pillars 110 using an impurity having the same conductivity type as the impurity of the common source region 105 .
[0035] A gate insulating layer 120 may be formed on the semiconductor substrate 100 , on which the pillars 110 are formed. A gate 125 may be formed to surround each of the pillars 110 . The gate insulating layer 120 may be formed by oxidizing the semiconductor substrate 100 , including the pillars 110 , or by depositing an oxide layer on the semiconductor substrate 100 , including the pillars 110 . The gate 125 may be formed to a height (or a thickness) corresponding to the channel formation region (a region between the drain region and the common source region). Therefore, the string selection switches SSW 1 and SSW 2 having vertical structures, are completed,
[0036] An insulating layer 130 may be formed to cover the semiconductor substrate 100 , on which the string selection switches SSW 1 and SSW 2 are formed. The insulating layer 130 may have a thickness sufficient to bury the string selection switches SSW 1 and SSW 2 . The insulating layer 130 may be planarized to expose the drain region 115 . An ohmic layer 135 may be formed in the exposed drain region 115 via a conventional process. The ohmic layer 135 may be, for example, a silicide.
[0037] Referring to FIG. 5 , first interlayer insulating layers 140 a , 140 b, 140 c, 140 d, and 140 e and second interlayer insulating layers 145 a, 145 b, 145 c, and 145 d are alternately formed on the insulating layer 130 to form an insulating structure. For example, first interlayer insulating layer 140 e may be located in the uppermost layer of the insulating structure, The first interlayer insulating layers 140 a, 140 b , 140 c, 140 d, and 140 e may have an etch selectivity that is different than an etch selectivity of the second interlayer insulating layers 145 a, 145 b , 145 c, 145 d and 145 e.
[0038] As illustrated in FIG. 6 , a certain portion of the insulating structure is etched to form a through-hole 150 exposing the ohmic layer 135 , Certain portions of the first interlayer insulating layers 140 a , 140 b, 140 c, 140 d, and 140 e, which are exposed through the through-hole 150 , may be are removed by, for example, a wet etch method. Therefore, the etched first interlayer insulating layers 140 a , 140 b, 140 c, 140 d, and 140 e are narrower than the second interlayer insulating layers 145 a, 145 b, 145 c, and 145 d.
[0039] Drain regions 155 of the switching devices SW 1 , SW 2 , SW 3 , and SW 4 are formed in spaces from which the first interlayer insulating layers 140 a, 140 b, 140 c, 140 d, and 140 e are removed. Therefore, the drain regions of the switching devices are exposed through a sidewall of the through-hole 150 .
[0040] The drain regions 155 may include, for example, a semiconductor layer, such as a silicon (Si) layer, a silicon germanium (SiGe) layer, a gallium arsenide (GaAs) layer, or a doped polysilicon layer, or a metal layer, such as tungsten (W), copper (Cu), titanium nitride (TIN), tantalum nitride (TaN), tungsten nitride (WN), molybdenum nitride (MoN), niobium nitride (NbN), titanium silicon nitride (TiSiN) titanium aluminum nitride (TiAlN), titanium boron nitride (TiBN), zirconium silicon nitride (ZrSiN), tungsten silicon nitride (WSiN), tungsten boron nitride (WBN), zirconium aluminum nitride (ZrAlN), molybdenum silicon nitride (MoSiN), molybdenum aluminum nitride (MoAlN), tantalum silicon nitride (TaSiN), tantalum aluminum nitride (TaAlN), titanium (Ti), molybdenum (Mo), tantalum (Ta), titanium silicide (TiSi), tantalum silicide (TaSi), titanium tungsten (TiW), titanium oxynitride (TiON), titanium aluminum oxynitride (TiAlON), tungsten oxynitride (WON), or tantalum oxynitride (TaON).
[0041] Referring to FIG. 7 , a channel layer 160 is formed along a surface defining the through-hole 150 . The channel layer 160 may include a conductive semiconductor layer, such as an impurity doped semiconductor layer. The channel layer 160 may have a conductivity type that is opposite to the conductivity type of the drain regions 155 . A first buried insulating layer 165 is formed in the through-hole 150 , over the channel layer 160 . At this time, the first buried insulating layer 165 may be provided to prevent the channel layer 160 from being lost when the first and second separation holes are formed.
[0042] Referring to FIG. 8 , a first separation hole H 1 for node separation is formed in a space between through-holes 150 to separate adjacent nodes. The first separation hole H 1 may be formed in the insulating structure between the string selection switches SSW 1 and SSW 2 . The second interlayer insulating layers 145 a, 145 b, 145 c, and 145 d, which are exposed through the first separation hole HI, are removed to form second separation holes H 2 . Since the first interlayer insulating layers 140 a, 140 b, 140 c, 140 d, and 140 e have an etch selectivity that is different than an etch selectivity of the second interlayer insulating layers 145 a, 145 b, 145 c, and 145 d, only the second interlayer insulating layers 145 a, 145 b, 145 c, and 145 d may be selectively removed. Therefore, the first separation holes H 1 are substantially perpendicular to a surface of the semiconductor substrate 100 , and the second separation holes H 2 are substantially parallel to the surface of the semiconductor substrate 100 .
[0043] Referring to FIG. 9 , a gate insulating layer 170 is formed on a surface defining each of the second separation holes H 2 . A gate electrode 175 is formed within each of the second separation holes H 2 . The gate insulating layer 170 may include, for example, silicon oxide or silicon nitride, or an oxide or a nitride of a metal, such as Ta, Ti, barium titanate (BaTi), barium zirconium (BaZr), zirconium (Zr), hafnium (Hf), lanthanum (La), aluminum (Al), or zirconium silicide (ZrSi). The gate electrode 175 may include a semiconductor layer, such as, for example, a Si layer, a SiGe layer, or an impurity doped GaAs layer, or a meta containing layer, such as, for example, W, Cu, TiN, TaN, WN, MoN, NbN, TiSiN, TiAlN, TiBN, ZrSiN, WSiN, WBN, ZrAlN, MoSiN, MoAlN, TaSiN, TaAlN, Ti, Mo, Ta, Tisi, TaSi, TiW, TiON, TiAlON, WON, or TaON. Next, a second buried insulating layer 178 may be formed the first separation hole H 1 . The second buried insulating layer 178 may include a layer having an etch selectivity that is different than an etch selectivity of the first buried insulating layer 165 .
[0044] Referring to FIG. 10 , the first buried insulating layer 165 buried in the through-hole 150 may be selectively removed to expose the channel layer 160 . A variable resistance layer 180 is deposited on an exposed surface of the channel layer 180 . The variable resistance layer 180 may include various materials, such as a Pr1-xCaxMnO3 (PCMO) layer, if the variable resistor is a ReRAM, a chalcogenide layer, if the variable resistor is a PCRAM, a magnetic layer, if the variable resistor is a MRAM, a magnetization reversal device layer, if the variable resistor is a spin-transfer torque magnetoresistive RAM (STTMRAM), or a polymer layer, if the variable resistor is a polymer RAM (PoRAM). At this time, current characteristic of the device may be controlled according to control of a thickness of the variable resistance layer 180 .
[0045] A third buried insulating layer 185 may be formed within the through-hole 150 , over the variable resistance layer 180 . Next, a bit line 190 is formed to be in contact with the channel layer 160 and the variable resistance layer 180 and therefore, the variable resistance memory device having a stacked structure is completed.
[0046] As illustrated in FIG. 11 , in the resistance memory cell, the drain regions 155 are located adjacent to the gate electrodes 175 , and the channel layer 160 and the variable resistance layer 180 are located adjacent to the drain regions. Therefore, when current is provided from the bit line 190 , current selectively flows along the channel layer 160 or the variable resistance layer 180 according to an on/off condition of the switching devices SW 1 , SW 2 , SW 3 , and SW 4 .
[0047] Thus, effective channel lengths (see EC 1 of FIG. 11 ) of the switching devices SW 1 , SW 2 , SW 3 , and SW 4 in the exemplary implementation may be substantially increased as compared with an effective channel length (see EC 2 of FIG. 11 ) of a conventional 3D switching device. Therefore, switching characteristics of the switching devices SW 1 , SW 2 , SW 3 , and SW 4 may be improved without increasing a size of the switching devices SW 1 , SW 2 SW 3 , and SW 4 .
[0048] FIG. 12 shown an alternative exemplary implementation that lacks the first separation holes H (as shown in FIG. 8 ). In this exemplary implementation, the same voltage may be provided to gate electrodes 175 located in the same layer. This structure may be formed by selectively removing second interlayer insulating layers 145 a , 145 b, 145 c, and 145 d without the forming of the first separation hole H 1 .
[0049] As illustrated in FIG. 13 , a channel layer 160 a may be formed on only a portion of a sidewall that defines a through-hole (see 150 of FIG. 6 ) that faces each of the gate electrodes 175 . That is, since drain regions 155 are located below and on gate electrodes 175 , the channel layer 160 a may not affect the operation of the device even when the channel layer 160 a is located in a overlapping region of the gate electrode 175 and the through-hole.
[0050] The above exemplary implementations are illustrative and not limitative. Various alternatives and equivalents are possible. The invention is not limited by the exemplary implementations described herein. Nor is the invention limited to any specific type of semiconductor device. Other additions, subtractions, or modifications are obvious in view of the present disclosure and are intended to fall within the scope of the appended claims. | A variable resistance memory device includes a plurality of cell gate electrodes extending in a first direction, wherein the plurality of cell gate electrodes are stacked in a second direction that is substantially perpendicular to the first direction, A gate insulating layer surrounds each cell gate electrode of the plurality of cell gate electrodes and a cell drain region is formed on two sides of the each cell gate electrode of the plurality of cell gate electrodes A channel layer extends in the second direction along the stack of the plurality of cell gate electrodes, and a variable resistance layer contacting the channel layer. | 6 |
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent application Ser. No. 12/117,673, filed May 8, 2008, which is a continuation of U.S. patent application Ser. No. 11/053,410, filed Feb. 7, 2005 and issued on Aug. 23, 2011 as U.S. Pat. No. 8,002,830, which claims the benefit of U.S. Provisional Patent Application Ser. No. 60/542,514, filed Feb. 6, 2004, the entireties of all of which are incorporated by reference herein.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to the use of surface modified biocompatible materials to promote the attachment of bone or bone-like cells to an implant surface. The surface of the biomaterials, which may include hydrogels, when modified in accordance with the description herein, directs the cells that migrate to the implant site to differentiate into cells that attach and lay down bone or bone-derivative material, or cartilage or cartilaginous material further enhancing the biocompatibility of the implanted device.
[0004] 2. Background Art
[0005] Materials used in the construction of implantable medical devices must be nontoxic, nonantigenic, and noninflammatory. Hydrogels are a preferred type of polymeric material for implantable devices. Because of their high water content, analogous to living tissue, they are superior in biocompatibility to non-hydrous polymeric materials.
[0006] U.S. Pat. No. 5,981,826, issued to Ku et al., describes the preparation of polyvinyl alcohol hydrogels (PVA-H) by physically crosslinking an aqueous solution of polyvinyl alcohol (PVA) to produce a gel. The crosslinking is accomplished by subjecting the aqueous PVA solution to multiple cycles of freezing and thawing. One limitation of the prior art is that the hydrogels produced are relatively nonporous and the pore size and degree of porosity, that is the density of the pores within the hydrogel, cannot vary independently of the mechanical properties or stiffness of the hydrogel.
[0007] Methods for producing certain porous hydrogels also exist in the art. U.S. Pat. No. 6,268,405,0 issued to Yao et al., describes methods for creating porous PVA-Hs by including immiscible materials in the polymerization process. After the hydrogel is polymerized, the included immiscible materials are washed out of the hydrogel by an appropriate solvent, yielding pores which are broadly distributed throughout the hydrogel. Controlling the size and density of the pores is accomplished by varying the molecular weight of the immiscible materials. A disadvantage of Yao et al. is that the range of attainable pore sizes is limited. Moreover, the invention of Yao et al. is limited in that it can only produce hydrogels whose pores extend throughout the hydrogel. The pores in Yao et al. are intended to create vascularization of the hydrogel in soft or non-load bearing tissue. A further disadvantage of Yao et al. is that the pore sizes are broadly distributed about the average pore size.
[0008] In addition to crosslinking by physical means, hydrogels may be chemically crosslinked using, for example, methods similar to those described by Müller in U.S. Pat. No. 5,789,464. Similarly, chemical crosslinking or polymerization methods may also be used to adhere hydrogels to surfaces, including biological tissues. U.S. Pat. No. 5,900,245, issued to Sawhney et al., describes applications of these techniques. These and other methods for the crosslinking or further polymerization of hydrogels are derived from methods used in the polymer industry and are well known in the art.
[0009] Artificial discs intended for the replacement of a damaged intravertebral disc have been described. These are typically articulated devices comprising two rigid metal plates adhered to opposite ends of an elastomeric core. In use, the artificial disc is placed in the intervertebral space and the metal plates are secured to the surfaces of adjacent vertebrae. Various embodiments of artificial discs of this type are described in U.S. Pat. Nos. 5,674,296 and 6,156,067, issued to Bryan et al., U.S. Pat. No. 5,824,094, issued to Serhan et al., U.S. Pat. No. 6,402,785, issued to Zdeblick et al. More recent embodiments, e.g. U.S. Pat. No. 6,419,704, issued to Ferree and U.S. Pat. No. 6,482,234, issued to Weber et al., include descriptions of elastomeric cores that may be formed from materials with different elasticities to better mimic the native structure of spinal discs.
[0010] The disadvantages of the artificial disc devices of the prior art are numerous. These prior art devices require the mechanical attachment of rigid artificial materials, such as titanium, directly to the bone with screws, staples, nails, cement, or other mechanical means. These rigid materials are only minimally compatible with natural, living bone and separation of the implant from the bone is often observed over long-term implantation. In addition, materials used in artificial discs of the prior art have physical and mechanical properties distinctly different from those of natural spinal, discs and thus, inadequately duplicate the desired properties of native spinal discs.
[0011] Vertebral fusion is still the most commonly performed procedure to treat debilitating pain associated with degenerative spinal disc disease or disc trauma, despite the fact that the procedure has many drawbacks. Vertebral fusion increases stress and strain on the discs adjacent to the fusion site, and it is now widely accepted that fusion is responsible for the accelerated degeneration of adjacent levels. Current multicomponent spinal disc prosthesis designs, elastomeric cores with metal plates on both the upper and lower surfaces, are susceptible to problems with interfacial bonding and wear. These designs have shown spontaneous device detachment due to retraction of bone tissue from the metal surface.
[0012] Bone ingrowth and attachment in the art has often required the use of bone promoting growth factors. For example, U.S. Pat. No. 5,108,436, issued to Chu et al., describes using a porous implant for use in load bearing bone replacement which is used in combination with an osteogenic factor such as TGF-β.
[0013] Biomedical devices which are implanted in or around bone often fail because of fibrinogen encapsulation of the implant instead of cellular attachment to the implant itself. This encapsulation is a defensive reaction attempting to minimize contact between the body and the implant and is considered a sign of implant incompatibility.
[0014] Moreover, the art of bone ingrowth to implantable surface contains a multitude of examples relating to porous directed ingrowth where bone essentially grows into and around channels of the implant. For example, U.S. Pat. No. 4,911,720, issued to Collier et al., discusses the ingrowth of bone into interconnecting pores which essentially locks bone into place. This method is disadvantageous in that bone does not actually attach to the material, instead bone attaches to other bone around the implant. In the unfortunate event that an implant must be removed, this type of Collier ingrowth results in large amounts of disruption to the surrounding bone tissue.
SUMMARY OF THE INVENTION
[0015] The present invention describes a biomaterial for implantation into the body. The biomaterial, which can be a hydrogel, possesses a textured surface which is comprised of superficial surface pores. Stated differently, the pores on the surface of the hydrogel substrate do not extend throughout the hydrogel but instead remain within a region near the surface. The hydrogel substrate can be comprised of two or more pore sizes. Specifically, the pores of the first size each have a diameter of between 3 and 1000 micrometers, preferably between 10 and 300 micrometers, and preferably between 30 and 100 micrometers. Further, the pores of the second size would each have a diameter of between 0.5 to 20 micrometers, preferably between 1 to 10 micrometers, and preferably between 2 and 5 micrometers. One embodiment of the present invention provides the second, smaller pores disposed within the first, larger pores. The superficial pores of the present invention extend into the hydrogel substrate less than 1 millimeter, preferably 500 micrometers, and preferably 200 micrometers, from the surface. The hydrogel substrate of the present embodiment can comprise polyvinyl alcohol having a water content of at least 5% and preferably at least 30%.
[0016] The present invention is also drawn to a hydrogel substrate comprising a hydrogel surface having thereon a plurality of first substantially uniform superficial pores and a unique plurality of second substantially uniform superficial pores. This hydrogel can possess two different yet substantially uniform superficial pore sizes grouped into a first, larger pore size and a second, smaller pore size. The pores of one size are substantially uniform in diameter relative to the other pores of the same size. Specifically, the first pores have an average diameter of between 2 and 600 micrometers, preferably between 5 and 200 micrometers, and preferably between 20 and 60 micrometers. Further, the second pores have an average diameter of between 0.1 and 10 micrometers, preferably between 0.2 to 5 micrometers, and preferably between 0.5 to 2 micrometers. The superficial pores of the present invention can be arranged so that the smaller, second pores are within the larger, first pores. The superficial pores of the present invention extend into the hydrogel substrate less than 1 millimeter, preferably no more than 500 micrometers, and preferably no more than 200 micrometers. The hydrogel substrate of the present embodiment can be made up of polyvinyl alcohol having a water content of at least 5% and preferably at least 30% w/w of the overall hydrogel.
BRIEF DESCRIPTION OF DRAWINGS
[0017] FIG. 1 is a spinal disc replacement device made in accordance with one embodiment of the present invention.
[0018] FIG. 2 is an example of a superficial surface pore construct exemplary of one embodiment of the present invention.
[0019] FIG. 3 are multiple types of superficial surface pores embodied by the present invention.
[0020] FIG. 4 is a graph of cell proliferation seen on the surfaces of FIG. 3 .
[0021] FIG. 5 is a graph of increased bone or bone-like cell markers resulting from exposure to the surfaces of FIG. 3 .
[0022] FIG. 6 is an image of a substrate which has been generated in accordance with the present invention. The upper image is a further magnification of the image in the lower portion of FIG. 6 .
DETAILED DESCRIPTION OF THE INVENTION
[0023] The present invention is drawn to a biomaterial substrate which may comprise a hydrogel surface having thereon a plurality of first substantially uniform superficial pores and a unique plurality of second substantially uniform superficial pores. Specifically, the pores of the first size preferably each have a diameter of between 3 and 1000 micrometers, preferably between 10 and 300 micrometers, and preferably between 30 and 100 micrometers, including without limitation, pores with a cross-section of 30, 40, 50, 60, 70, 80, 90, and 100 micrometers. Further, the pores of the second size preferably each have a diameter of between 0.5 to 20 micrometers, preferably between 1 to 10 micrometers, and preferably between 2 and 5 micrometers, including without limitation, pores with a cross-section of 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, and 20 micrometers. It should be readily apparent to one of ordinary skill in the art that the use of the term diameter also would encompass the cross-section of the pore when not a perfect circle. In fact, the term “pore” should not be read to be limited to circular or spherical shapes. Squares, polygons, triangles, octagons, quadrahedrens, or any other geometric or amorphic structure would perform the function for the invention if properly positioned and sized. One embodiment of the present invention provides the second, smaller pores within the first, larger pores. The invention provides that third, fourth, fifth, and greater substantially uniform pore sizes can be on the hydrogel surface. By substantially uniform it is meant that the pore sizes of a particular class (e.g., first, second, etc.) do not vary more than 10%, preferably the pore sizes of a particular class vary less than 5%, 4%, 3%, more preferably less than 2%, and preferably less than 1% or 0.5%.
[0024] The superficial pores of the present invention would extend into the hydrogel substrate no more than 1 millimeter, preferably 500 micrometers, and preferably 200 micrometers, from the surface. The hydrogel substrate of the present embodiment can comprise polyvinyl alcohol having a water content of at least 5% and preferably at least 30% w/w of the overall hydrogel.
[0025] The present invention is also drawn to a hydrogel substrate comprising a hydrogel surface having thereon a plurality of first substantially uniform superficial pores and a unique plurality of second substantially uniform superficial pores. This hydrogel substrate can possess two different yet substantially uniform superficial pore sizes grouped into a first, larger pore size and a second, smaller pore size. The pores of one size are substantially uniform in diameter relative to the other pores of the same size. Specifically, the first pores have an average diameter of between 2 and 600 micrometers, preferably between 5 and 200 micrometers, and preferably between 20 and 60 micrometers. Further, the second pores have an average diameter of between 0.1 and 10 micrometers, preferably between 0.2 to 5 micrometers, and preferably between 0.5 to 2 micrometers.
[0026] The superficial pores of the present invention can be arranged so that the smaller, second pores are within the larger, first pores. The superficial pores of the present invention can extend into the hydrogel substrate preferably no more than 1 millimeter, preferably no more than 500 micrometers, and preferably no more than 200 micrometers. The hydrogel substrate of the present embodiment can be made up of polyvinyl alcohol having a water content of at least 5% and preferably at least 30% w/w of the overall hydrogel.
[0027] In one embodiment of the invention, the superficial pores of the substrate described herein can be arranged in a regular repeating fashion. Such a patter or waffle structure can be used in embodiments of varying pore size as well as in embodiments where the smaller superficial pores are within the area of the larger superficial pores.
[0028] A method provided by the present invention of making a hydrogel substrate possessing a textured surface required by the present invention comprises using an extremely accurate etching technology to generate a mold, pouring a liquid solution of the hydrogel into the mold, allowing the liquid hydrogel to polymerize and/or crosslink while in the mold, and removing the solid hydrogel substrate from the mold. The extremely accurate etching technology can be MEMS technology or its equivalent. Also, the hydrogel substrate made from this method could be a polyvinyl alcohol hydrogel having a water content of at least 5% and preferably at least 30% w/w of the overall hydrogel.
[0029] The present invention also includes a method for making a hydrogel substrate by contacting solid objects with a liquid hydrogel, allowing the hydrogel to polymerize and crosslink while the solid objects are at least partially immersed in the hydrogel, and removing those solid objects from the polymerized and crosslinked hydrogel to form superficial pores therein. The solid objects used to impart the superficial pores may be made of polystyrene beads. Also, the solid objects used to impart the superficial pores may be grit, sand, silicon, silica, and ultra-fine particulate matter. The solid objects used to create the superficial pores can have a diameter of between 3 and 1000 micrometers, preferably between 10 and 300 micrometers, and preferably between 30 and 100 micrometers.
[0030] The solid objects used to create the superficial pores of this invention can be removed by use of an organic solvent or other washing means. This hydrogel can be comprised of polyvinyl alcohol possessing a water content of at least 5% w/w of the overall hydrogel.
[0031] Accordingly, the present invention is directed to an implantable hydrogel substrate product, a method of making that product, and a method of using that product which substantially improves upon the limitations existing in the art. The invention provides methods of selectively promoting cellular residence and/or differentiation over a surface as described herein. To achieve these and other advantages in accordance with the purpose of the invention, as embodied and broadly described herein, the invention includes a load bearing biocompatible hydrogel for medical implantation that promotes bone attachment. The hydrogel consists of a surface component which has been optimized for implantation. This is accomplished through pores on the surface having a controlled range in distribution of size. The surface pores are superficial and do not extend throughout the hydrogel.
[0032] Hydrogels are materials whose state is between that of a solid and of a liquid. Gels consist of polymeric, i.e. long chain, molecules linked together to form a three-dimensional network and are embedded in a liquid medium. In the case of hydrogels, the liquid medium comprises water. The polymer backbone of hydrogels is formed by hydrophilic monomer units and may be neutral or ionic. Examples of neutral and hydrophilic monomer units are ethylene oxide, vinyl alcohol, (meth)acrylamide, N-alkylated (meth)acrylamides, N-methylol(meth)acrylamide, N-vinylamides, N-vinylformamide, N-vinylacetamide, N-vinyl-N-methylacetamide, N-vinyl-N-methylformamide, hydroxyalkyl (meth)acrylates such as hydroxyethylmethacrylate, vinylpyrrolidone, (meth)acrylic esters of polyethylene glycol monoallyl ethers, allyl ethers, of polyethylene glycols, and sugar units such as glucose or galactose. Examples of cationic hydrophilic monomer units are ethyleneimine (in the protonated form), diallyldimethylammonium chloride and trimethylammonium propylmethacrylamide chloride. Examples of anionic monomer units are (meth)acrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, 2-acrylamido-2-methylpropanesulfonic acid, vinylsulfonic acid, vinylphosphonic acid, 2-methacryloyloxyethanesulfonic acid, 4-vinylbenzenesulfonic acid, allylsulfonic acid, vinyltoluenesulfonic acid and vinylbenzenephosphonic acid.
[0033] From the example listing above, a hydrogel for use in the present invention may be selected based upon its biocompatibility and stability at various hydration states. For the purposes of the present invention, a suitable hydrogel will have a moisture content of at least 5% w/w of the overall hydrogel, preferably at least 10%, 15%, 20%, 25%, 30%, 35%, 40%, 50%, 60%, 70%, or 80% w/w of the overall hydrogel.
[0034] Initial events following implantation of a biomaterial in an orthotopic surgical site include rapid adsorption of serum constituents onto the implant surface. The first cells that are likely to come into contact with the surface are polymorphonuclear cells, platelets, monocytes, and macrophages. These cells release bioactive factors that promote mesenchymal cell migration to the wound site. In addition to these natural factors associated with wound healing, surgeons frequently use bone graft and bone graft substitutes to improve bone formation. Such materials include osteoinductive agents such as demineralized bone matrix and bone morphogenetic protein. If appropriate signals are present mesenchymal cells with an osteoprogenitor phenotype will continue to differentiate into osteoblasts; of these a subset will become osteocytes. Ultimately, the newly formed bone will be remodeled via osteoclastic resorption. The invention provides that physical stimulation of cells via a controllably textured surface contributes to desired cellular differentiation, adhesion, and acceptance of the implant. The present invention also provides that well-known grafting agents may be incorporated into the hydrogel composition, which include, but are not limited to growth factors, angiogenic agents, antibiotics, and the like.
[0035] Chemically modified or polar surfaces are generally known to be able to produce more reactive protein adsorption to the implant surface than unmodified or non-polar surfaces. The increased reactivity of the proteins adsorbed onto the polar surface is thought to promote cellular adhesion to that surface. Therefore, the invention provides that the hydrogel composition can possess chemically modified or polar surfaces.
[0036] In general, many materials are well-tolerated in bone, but the success of long-term or chronic implantation often depends on the intimacy of the interface between the material surface and the bone. Microarchitecture of the surface is an important determinant of cell response. It has been observed that osteoblast phenotypic expression is surface-dependent. As described herein, specific surface characteristics enhance osteoblast differentiation while permitting proliferation, leading to optimal cell response to the implantation. Likewise, cartilage or cartilage-derivative cells show enhanced differentiation based on surface microarchitecture. Since both bone and cartilage cells are derived from mesenchymal stem cells and have as a common ancestor, osteoprogenitor cells, the present invention refers to bone and bone-like cells to encompass that branch of the differentiation pathway. Stated differently, the present invention provides for the differentiation of bone cells (for example osteocytes, osteoblasts, osteoclasts) as well as bone-like cells (for example chondrocytes or related cartilaginous tissue producing cells).
[0037] The mechanical properties of the material must be appropriate for the application. When the mechanical properties of the material are similar to the mechanical properties of the tissue adjacent to the implant, tissue tolerance of the artificial material is enhanced. Polymeric and elastomeric biomaterials can be fabricated with a wide range of mechanical properties, making them suitable for many applications as implantable devices. Because of their high water content, similar to that of living tissue, hydrogels are superior in biocompatibility to non-hydrous polymeric materials. Polyvinyl alcohol (PVA) is an example of a polymer that can be used to form hydrogels, and has been studied extensively for its potential in biomedical applications. Polyvinyl alcohol hydrogels (PVA-Hs) are biologically well tolerated and compatible with living cartilage tissue.
[0038] PVA-Hs can be produced from solution via repeated freezing and thawing cycles that increase the order of the microcrystalline regions, changing the dissolution properties, mesh size, and diffusion properties of the polymer. Also, PVA-Hs can be produced from solution via a slow and sustained transition through the freezing point of the solution. The mechanical properties of PVA-Hs can be varied over a wide range, and stable PVA gels can easily be produced to have an elastic modulus ranging from a few MPa, such as articular cartilage, to about 50 MPa, such as the stiffest portion of the annulus of spinal discs. Increasing the stiffness of a hydrogel can also be achieved through chemical crosslinking. Examples of chemical crosslinker groups are vinyl groups, allyl groups, cinnamates, acrylates, diacrylates, oligoacrylates, methacrylates, dimethacrylates, oligomethacrylates, or other biologically acceptable groups.
[0039] Increasing the porosity of a hydrogel substrate produces decreased mechanical strength. When porous hydrogels are used to provide the requisite surface of the present invention, it is advantageous that the porosity not extend throughout the hydrogel, but be limited to a relatively shallow depth below the surface. The thickness of the porous portion of the hydrogel is preferably less than 1 millimeter, less than 500 micrometers, and most preferable less than or equal to 200 micrometers.
[0040] The porosity of the hydrogel surface embodied in this invention may be realized in a variety of ways. Molds may be constructed with patterning on the appropriate surfaces of the cavities in the mold. Alternatively, the porosity can be produced by abrasion of a smooth hydrogel surface after molding. Abrading the surface can result in a surface textured such as desired in this invention. Techniques for applying and using abrasives are well known to those of skill in the art.
[0041] Using extremely accurate surface building or etching techniques, one can generate extremely intricate surfaces to use as a mold for a surface envisioned by the present invention. Solid free-form fabrication methods offer several unique opportunities for the construction of medical devices. Solid free-form fabrication methods can be used to selectively control composition within the build plane by varying the composition of printed material. This means that unconventional microstructures, such as those with complicated porous networks or unusual gradients, can be designed at a computer-aided design (CAD) terminal and built through a solid free-form process such as three-dimensional printing or MEMS micro-fabrication techniques.
[0042] In one embodiment of this invention the molds for casting the hydrogels are created using MEMS micro-fabrication techniques to produce materials with precise repetitive arrays. The microfabrication process uses commercially available, epoxy-based photoresist and standard photolithography masks and techniques to produce the specified surface architecture. The dimensions of features in the x-y plane of the surface are specified by the photomask. The height of the features is dictated by the thickness of the photoresist layer prior to exposure and development. Multiple photoresist layers may be cast and exposed with different masks to build up very complex structures. An example of one such complex feature, with a pseudofractal architecture is shown in the “snowflake” pattern, seen in FIG. 2 .
[0043] Photolithography is the process of transferring geometric shapes on a mask to the surface of a silicon wafer. The steps involved in the photolithographic process are wafer cleaning; barrier layer formation; photoresist application; soft baking; mask alignment; exposure and development; and hard-baking.
[0044] There are two types of photoresist: positive and negative. For positive resists, the resist is exposed with UV light wherever the underlying material is to be removed. In these resists, exposure to the UV light changes the chemical structure of the resist so that it becomes more soluble in the developer. The exposed resist is then washed away by the developer solution, leaving windows of the bare underlying material. The mask, therefore, contains an exact copy of the pattern which is to remain on the wafer.
[0045] Negative resists behave in just the opposite manner. Exposure to the UV light causes the negative resist to become polymerized, and more difficult to dissolve. Therefore, the negative resist remains on the surface wherever it is exposed, and the developer solution removes only the unexposed portions. Masks used for negative photoresists, therefore, contain the inverse (or photographic “negative”) of the pattern to be transferred.
[0046] MEMS fabrication of hydrogel mold surfaces for use in this invention may, for example, involve standard photolithography techniques and epoxy-based photoresists (SU-8 2000 series, MicroChem, Newton, Mass.) in a Class 10 cleanroom facility. Photolithography masks can be designed, for example, using a CAD program, or its equivalent, and supplied to order (DuPont Photomasks, Inc., Round Rock, Tex.).
[0047] One embodiment of this invention is an artificial intervertebral disc, comprising one or more hydrogels shaped substantially similarly to a natural intervertebral disc. The upper and lower surfaces of the hydrogel, or assembly of hydrogels, are constructed to have a textured surface with a defined level of porosity. That porosity depends primarily upon the size and number of the surface features of the mold used to create the surface texture.
[0048] Another embodiment of this invention is a substrate used to repair tissue that has been damaged either chronically or acutely. This substrate can be implanted at a damaged area such as knee cartilage, shoulder bursa repair, or other damaged area one skilled in the art would foresee.
[0049] FIG. 1 shows a spinal disc replacement envisioned by the present invention. The spinal disc has an upper portion 1 and a lower portion 2 . It is the surfaces of the upper portion 1 and lower portion 2 which possess the textured surface envisioned by the present invention. The upper portion 1 and lower portion 2 will be less elastic and more rigid than the inner region 4 which seeks to mimic the nucleus pulposus. Likewise, the spinal disc may have an intermediate region of elasticity 3 which further aids in the function of the spinal disc. The intermediate region of elasticity 3 may or may not differ from the elasticity of either the inner region 4 or the upper portion 1 or lower portion 2 .
[0050] The size of the pores comprising the textured surface of the hydrogel can aid in promoting adhesion of one cell type over the other. For example, bone cells can show better attachment and results on textured surfaces where the pores are larger than the pores on a textured surface where cartilage cells attach. The ability to promote bone cells to attach to a given surface as compared to cartilage cells can be considered in the design of an implant. For example, a biomedical implanted device which needs a more rigid attachment to the native bone might require the attachment of bone cells as opposed to cartilage cells, requiring using a surface with larger pores. Likewise, a different implant may need to induce cartilage development on the surface of the implant and would instead use the textured surface composed of overall smaller pores to enable that selection. Other factors such as the age, sex, and pre-existing medical condition of the patient would be considered depending upon the circumstances.
[0051] Conversely, the present invention provides for a hydrogel substrate that can be implanted which possesses multiple regions on that substrate capable of promoting the differentiation and attachment of both bone and bone-like cells such as, for example, osteocytes and chondrocytes. Such a surface would, after the migration of mesenchymal stem cells, promote the differentiation of the mesenchymal stem cell into the osteoprogenitor cell and ultimately into bone and cartilage cells on each type's respective region. Stated differently, the present invention provides for a single hydrogel substrate that has both bone cell promoting regions and cartilage, or bone-like cell, promoting regions.
[0052] Osteoblasts assume distinct morphologies depending on the architectural features of their substrate. On microrough surfaces, as long as the peak-to-peak distance is less than the length of the cell body, the cell bodies become more cuboidal, and anchor themselves to the surface through long dendritic filopodia. In contrast, on smoother surfaces osteoblasts flatten and spread, resulting in a fibroblastic appearance. The cell morphology correlates with the physiological behavior of the cells. On smooth surfaces, prostaglandin synthesis is low, TGF-β1 levels are low, alkaline phosphatase specific activity is low, and osteocalcin levels are low, whereas proliferation rates are relatively high in comparison with cells cultured on rougher surfaces. That is, a greater number of cells may be present on smooth surfaces, but the cells on textured surfaces show greater tendency to proliferate into bone or bone-like cells.
[0053] Responsiveness to the surface also depends upon the state of maturation of the cell in the osteoblast lineage. Examinations of numerous cell lines and primary cell cultures from the multipotent fetal rat calvarial cells to the osteocyte cell line MLO-Y4 have occurred. These experiments indicate that as cells become more mature, the stimulatory effect of the microrough surface on differentiation becomes attenuated. It is, however, only on textured surfaces and only in the presence of bone morphogenic protein-2 (BMP-2), that fetal rat calvarial cells are able to establish three dimensional nodules that form mineral in a physiological relevant manner. The results support in vivo observations that a mineral can affect cells directly on the surface as well as distal to the biomaterial indicating that the extracellular signaling factors released by the cells in direct contact with material are sensed by other cells in the microenvironment, and potentially systematically as well.
[0054] The surface texture is created by the distribution of pores which do not continue throughout the hydrogel, or stated differently, are superficially located on the hydrogel substrate. These pores can be broken into at least two size groups: large pores and small pores. The large pores can range in size from 3 to 1000 micrometers in diameter. Preferably, the large pores can range in size from 10 to 300 micrometers in diameter. And preferably, the large pores can range in size from 30 to 100 micrometers in diameter. The small pores are smaller in diameter. For example, the small pores can range in size from 0.5 to 20 micrometers in diameter. Preferably, the small pores can range in size from 1 to 10 micrometers. And preferably, the small pores can range in size from 2 to 5 micrometers. The present invention also provides for third, fourth, fifth, and greater numbers of pore sizes on the hydro gel substrate.
[0055] FIG. 2 depicts a superficial pore 20 as envisioned by the present invention. The superficial pore contains a large pore 10 and a small pore 15 . The small pores 15 are located within the large pore 10 . The small pores 15 , in this embodiment, are equally spaced from one another by one diameter and are positioned in a hexagonal layout.
[0056] The pores on the textured surface in this embodiment enable the surface to resemble native bone which has undergone osteoclastic resorption. Increasing the porosity of a PVA-H generally reduces the mechanical strength of the implant. When surface textured hydrogels are used to provide the requisite surface texture, it is advantageous for the pores not to extend throughout the hydrogel, but instead be limited to a relatively shallow depth below the textured surface. The thickness of the porous portion of the hydrogel is less than 1 millimeter, preferably less than 500 micrometers, and preferably less than or equal to about 200 micrometers.
[0057] In order to measure differentiation of cells into bone or bone-like cells four markers are known in the art. The presence of alkaline-phosphatase, TGF-β1, PGE 2 , and osteocalcin function as reliable indicators of cellular differentiation into bone or bone-like cells. Specifically, it has been shown that MG63 osteoblasts, NHOst cells, and fetal rat calvarial cells will attach to surfaces and then differentiate into secretory osteoblasts that exhibit increased levels of alkaline phosphatase activity and osteocalcin. As surface microroughness increases, levels of PGE 2 in the conditioned medium also increase. PGE 2 stimulates osteoclastic activity at high levels, but is required to be present at low levels for osteoblastic activity to occur. It has been previously shown that the elevated prostaglandin levels that are seen in cultures grown on rough microtopographies appear to be required for enhanced osteogenesis since inhibition of prostaglandin production by indomethacin blocks the increase in osteoblast phenotypic expression on these substrates.
[0058] TGF-β1 levels are also surface dependent. The amount of TGF-β1 produced by osteoblasts cultured on surfaces is modulated in a surface dependent manner by factors that regulate osteogenesis and subsequent bone resorption. Regulation of TGF-β1 is important to bone formation for a number of reasons. This growth factor stimulates proliferation of mesenchymal cells and enhances the production of extracellular matrix, particularly of type 1 collagen.
[0059] Osteocalcin is the most abundant non-collagenous protein in bone, comprising almost 2% of total protein in the human body. It is important in bone metabolism and is used as a clinical marker for bone turnover, but its precise function remains elusive. With no known enzyme activity, osteocalcin's function depends on its structure. That structure reveals a negatively charged protein surface that places five calcium ions in positions complementary to those in hydroxyapatite, the structural mineral component of bone. In addition to binding to hydroxyapatite, osteocalcin functions in cell signaling and the recruitment of osteoclasts and osteoblasts, which have active roles in bone resorption and deposition, respectively.
[0060] The hydrogels of the present invention may contain bioactive factors to further stimulate cell growth or differentiation. These factors, for instance attachment peptides, such as RGD containing peptides, and growth factors such as bone morphogenic proteins, insulin-like growth factor, platelet derived growth factor, fibroblast growth factor, cartilage-derived growth factor, transforming growth factor-beta, and parathyroid hormone related peptide, as well as other regulatory chemicals such as statins, prostaglandins, and mineral ions are well known in the art. These factors may be included in the hydrogels of this invention singly or in combination, and they may be included with or without their respective binding proteins.
[0061] The hydrogels of the present invention may also contain bone or cartilage forming cells (osteoblasts or chondrocytes) or precursor cells to bone and cartilage forming cells such as mesenchymal stem cells or osteoprogenitor cells. These precursor cells have the capacity to differentiate into bone and/or cartilage forming cells. Cells may be included in the hydrogels of the present invention alone or in combination with bioactive factors to further stimulate cell growth or differentiation.
[0062] Natural intervertebral discs have a tough outer fibrocartilaginous ring called the annulus fibrosus and a soft, inner, highly elastic structure called the nucleus pulposus. The artificial discs of the present invention may contain an inner core constructed to mimic the physical and mechanical properties of the natural nucleus pulposus, surrounded by an annular region constructed to mimic the physical and mechanical properties of the natural annulus fibrosus.
[0063] In one embodiment, these regions comprise hydrogels whose water content, degree of polymerization, and degree of crosslinking are routinely adjusted to produce the requisite physical and mechanical properties. The hydrogel comprising the inner core has a higher water content and/or a lower degree of polymerization and/or a lower degree of crosslinking to produce a relatively soft and elastic hydrogel. The hydrogel comprising the outer annular region has a lower water content and/or a higher degree of polymerization and/or crosslinking to produce a relatively hard outer hydrogel which mechanically is tough and stiff. The hydrogels comprising the upper and lower surfaces may substantially resemble the hydrogel comprising the annular region in terms of physical and mechanical properties, water content, and degrees of crosslinking and polymerization. The additional requirement, however, for the surfaces to be textured may allow or require a different combination of physical and mechanical properties in these hydrogels compared to the hydrogel comprising the outer annular region.
[0064] In yet another embodiment of the present invention, the hydrogel substrate can be a load bearing patch which can be used in the repair of partially or predominately damaged tissue. For example, the hydrogel substrate bearing the textured surface of the present invention can be relatively thin and small in diameter. That hydrogel substrate can then be placed where deteriorated, either acutely or chronically, cartilage was removed.
[0065] In yet another embodiment of the present invention, the hydrogel substrate can be assembled outside the body in a malleable form. The malleable form of the hydrogel substrate can then be placed in the intended area, be it a spinal disc replacement, knee cartilage replacement, shoulder bursa repair, or other use one skilled in the art would foresee. Once in the proper position, the malleable hydrogel substrate could be hardened or polymerized via photopolymerization. Radiation curing or photopolymerization (photo-induced free radical polymerization) has become an important and useful technique for applying and curing coatings, inks and adhesives. Radiation-curable compositions typically comprise as essential components one or more radiation-curable monomers and a photoinitiator. The compositions are applied as a coating to various articles and surfaces and the monomers are polymerized to form a film by exposing the coating of the radiation-curable composition to radiation, typically ultraviolet (UV) or electron-beam radiation. Examples of chemical crosslinker groups are vinyl groups, allyl groups, cinnamates, acrylates, diacrylates, oligoacrylates, methacrylates, dimethacrylates, oligomethacrylates, or other biologically acceptable photopolymerizable groups.
[0066] In yet another embodiment of the present invention, the biocompatible material used in implantation is selected from the group of polymers, ceramics, metallics, organo-metallics, or other known biocompatible materials. To be used as described herein, the materials need to be castable, formed by the use of molds, in order to have rendered upon the surfaces of the materials the necessary forms embodied in this invention. Castable ceramics would be a preferred selection as the materials are often formed in manners which resembled native bone or bone structures. Likewise, biocompatible metallic components could be fashioned using the various embodiments of this invention such to direct cellular attachment and proliferation at the surface of the implant.
EXAMPLES
Example 1
[0067] A simple mold surface pattern in accordance with this invention, for example, is an array of cylinders which are 5 μm in diameter and 5 μm in height. To construct a mold surface with this pattern, a 4-inch diameter silicon wafer is coated with a 5 μm thick layer of SU-8 2005 by spin coating at 3000 rpm for about 30 seconds. The wafer is then placed on a hotplate at 65° C. for about 1 minute and then at 95° C. for about 2 minutes. The wafer is then exposed to UV light through a photomask defining the array of cylinders using, for example, a mask aligner (Karl Suss MA-6). The exposure time is calculated to give an exposure energy of 75 mJ/cm 2 at a wavelength of 365 nm. The exposed areas of the photoresist are then crosslinked by heating the wager on a hotplate at 65° C. for about 1 minute and then at 95° C. for about 1 minute. The unexposed areas of the photoresist are then dissolved away by immersing the wafer in solvent (SU-8 Developer, MicroChem, Newton, Mass.) for about 1 minute with continuous gentle agitation. The completed wafer is then rinsed, for example, with isopropyl alcohol and dried in a stream of nitrogen. Profilometry measurements and evaluation by scanning electron microscopy can be used to verify that the desired surface pattern is produced.
Example 2
[0068] A more complicated pattern for a hydrogel mold surface, in accordance with the present invention when generated could for example, consist of an array of cylinders 100 μm in diameter and 100 μm in height. Each cylinder is topped with a smaller array of cylinders, 5 μm in diameter, and 5 μm in height. The construction of such a mold requires two layers of photoresist and two separate exposures of those layers. First, a 4-inch diameter silicon wafer is coated with a 100 μm thick layer of SU-8 2050 by spin coating at 1700 rpm for about 30 seconds. The wafer is then placed on a hotplate at 65° C. for about 4 minutes and then at 95° C. for about 1 minute. The wafer is then exposed to UV light through the photomask defining the array of large cylinders, using, for example, a mask aligner (Karl Suss MA-6). The exposure time is calculated to give an exposure energy of 450 mJ/cm 2 at a wavelength of 365 nm.
[0069] The exposed areas of the photoresist are then cross-linked by heating the wafer on a hotplate at 65° C. for about 1 minute and then at 95° C. for about 9 minutes. Without developing the first layer, the wafer was coated with a 5 μm thick layer of SU-8 2005 by spin coating at 3000 rpm for about 30 seconds. The wafer is then placed on a hotplate at 65° C. for about 1 minute and then at 95° C. for about 2 minutes. The wafer is then exposed to UV light through the photomask defining the array of small cylinders using, for example, a mask aligner (Karl Suss, MA-6). The exposure time is calculated to give an exposure energy of 75 mJ/cm 2 at a wavelength of 365 nm. The exposed areas of the photoresist are then crosslinked by heating the wafer on a hotplate at 65° C. for about 1 minute and then at 95° C. for about 1 minute. Finally, the unexposed areas of both photoresist layers are then dissolved away by immersing the wafer in solvent (SU-8 Developer, MicroChem, Newton, Mass.) for about 9 minutes with continuous gentle agitation. The completed wafer is then rinsed with, for example, isopropyl alcohol and dried in a stream of nitrogen. Profilometry measurements and evaluation by scanning electron microscopy can be used to verify that the desired surface pattern has been produced.
Example 3
[0070] Under the methods of this invention, enhanced differentiation of cells into bone or bone-like cells is seen. Specifically, experiments were run using the PVA-H of this invention in multiple forms. This description references FIGS. 3-5 for clarity. As shown in FIG. 3 there were seven conformations of the surface topography taught by this invention used in this experiment—one being smooth hydrogel. Specifically, conformation is described using a two number nomenclature system such as PVA-H 10/2. PVA-H 10/2 refers first to the size of the large pore on the surface. As described above, the large pore can exist in a complex structure resembling a snowflake. The number 10 in the first position represents a large pore of 100 μm in diameter. The number in the second position of the nomenclature system refers to the size and arrangement of the small pores superimposed on the large pore surface. The second position numbers of 2, 5, and 10 refer to a diameter of 2 μm, 5 μm, and 10 μm, respectively. The spacing and orientation of the small pores on the large pore surface follows a hexagonal grid with a spacing between the small pores of twice the diameter of the small pores.
[0071] Moving clockwise through FIG. 3 , surfaces are shown possessing a 100 μm large pore with a 2 μm small pore (10/2) 50 , a 100 μm large pore with a 5 μm small pore (10/5) 55 , a 100 μm large pore with a 10 μm small pore (10/10) 60 , no large pore with 10 μm small pores (0/10) 65 , no large pore with 5 μm small pores (0/5) 70 , and no large pore with 2 μm small pores (0/2) 75 . Not shown is smooth PVA-H which would receive the 0/0 designation in the above described nomenclature.
[0072] FIGS. 4 and 5 when taken together indicate that while tissue culture plastic provides for the greatest amount of cellular proliferation, textured PVA-Hs promote increased differentiation into bone or bone-like cells. MG63 cells were cultured in conditioned media on the surfaces. Specifically, the cells cultured on the 10/10 conformation 60 showed the greatest level of secreted osteocalcin. The next highest amount of osteocalcin secretion was seen in the 10/5 conformation 55 . This indicates the enhanced ability to generate differentiation into bone or bone-like cells by the mimicking of native osteoclastic resorption sites on PVA-H by the use of the present invention.
[0073] FIG. 6 is an image of the surface of a substrate manufactured in accordance with the present invention. The image shows the surface of a hydrogel that was cast in a mold similar to those depicted in FIG. 3 . It should be noted that the substrate could have been generated with this pattern out of any of the materials described herein.
Example 4
[0074] Solid polystyrene objects having complex shapes may be fabricated from uniform polystyrene beads by chemically attaching beads of different sizes. This is illustrated by the following example.
[0075] To a suspension of carboxyl-modified polystyrene beads (20.3 μm+/−0.43 μm diameter, Bangs Laboratories) in 20 mM MES, pH 4.5 is added a 10-fold excess of water-soluble carbodiimide, 1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride. After 15 minutes at room temperature, the beads are washed twice by centrifugation and suspension in 20 mM HEPES, pH 7.5 and then resuspended in the same buffer. This suspension is added to a stirred suspension of a sufficient amount of amino-modified polystyrene beads (3.10 μm+/−0.06 μm diameter, Bangs Laboratories) to give a 25-fold molar excess of amino groups over carboxyl groups, in the same buffer. After 3 hours at room temperature, the unreacted excess smaller beads are removed. Microscopic examination shows substantially monodisperse particles composed of 20-μm beads having the majority of their surface covered with a single layer of 3-μm beads.
[0076] The polystyrene objects of the foregoing example may be used as a template to fabricate a mold for providing the desired porous surface of the hydrogels of the present invention. This may be accomplished by making a metallic replica of a surface comprising a plurality of polystyrene objects using sputtering and/or metal plating techniques and the like, all of which are well known to those skilled in the art. The metallic replica thus produced may be replicated again and reinforced with further metal or other components, again using methods well known to those skilled in the art. The result is a mold suitable for producing the complex surface texture of the hydrogels of the present invention.
[0077] Although the invention has been described with reference to a particular preferred embodiment with its constituent parts, features and the like, these are not intended to exhaust all possible arrangements, mechanical and electrical equivalents, or features, and indeed many other modifications and variations will be ascertainable to those of skill in the art. | Implantable biomaterials, particularly hydrogel substrates with porous surfaces, and methods for enhancing the compatibility of biomaterials with living tissue, and for causing physical attachment between biomaterials and living tissues are provided. Also provided are implants suitable for load-bearing surfaces in hard tissue repair, replacement, or augmentation, and to methods of their use. One embodiment of the invention relates to an implantable spinal disc prosthesis. | 1 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to cuticle care and, more specifically, to a cuticle oil dispensing pen with a ceramic cuticle stone. Cuticle care usually involves a two step process involving moisturizing the cuticle and then cutting and smoothing it. The present invention simplifies this procedure by providing a dispensing pen having a reservoir containing cuticle oil that is delivered by seepage through the stone thereby moisturizing the cuticle simultaneously as the ceramic stone cuts and smoothes it. The present invention provides a fast, efficient means for cuticle care overcoming the shortcomings of the prior art.
2. Description of the Prior Art
There are other heated devices designed as applicators. While these applicators may be suitable for the purposes for which they were designed, they would not be as suitable for the purposes of the present invention, as hereinafter described.
SUMMARY OF THE PRESENT INVENTION
A primary object of the present invention is to provide a cuticle oil dispenser pen.
Another object of the present invention is to provide a cuticle oil dispenser pen having a body with a reservoir for storing cuticle oil.
Yet another object of the present invention is to provide a cuticle oil dispenser pen having a porous ceramic cuticle stone projecting from one end of the dispenser pen's body.
Still yet another object of the present invention is to provide a cuticle oil dispenser pen with a channel communicating between the reservoir and the porous ceramic stone.
Another object of the present invention is to provide a cuticle oil dispenser pen that will deliver oil to moisturize the cuticle simultaneously with treatment from the porous ceramic cuticle stone.
Still another object of the present invention is to provide a cuticle oil dispenser pen with a refillable reservoir.
Additional objects of the present invention will appear as the description proceeds.
The present invention overcomes the shortcomings of the prior art by providing a cuticle oil dispenser pen that simplifies the process of cuticle treatment by dispensing moisturizing cuticle oil through the porous ceramic stone while cutting and smoothing the cuticle.
The foregoing and other objects and advantages will appear from the description to follow. In the description reference is made to the accompanying drawings, which forms a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. These embodiments will be described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that structural changes may be made without departing from the scope of the invention. In the accompanying drawings, like reference characters designate the same or similar parts throughout the several views.
The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is best defined by the appended claims.
BRIEF DESCRIPTION OF THE DRAWING FIGURES
In order that the invention may be more fully understood, it will now be described, by way of example, with reference to the accompanying drawing in which:
FIG. 1 is an illustrative view of the present invention in use.
FIG. 2 is an illustrative view of the present invention.
FIG. 3 is a side view of the present invention.
FIG. 4 is a side view of the present invention.
FIG. 5 is a side sectional view of the present invention.
FIG. 6 is an exploded side sectional view of the present invention.
FIG. 7 is an illustrative view of the present invention in use.
FIG. 8 is a detailed illustrative view of the present invention in use.
DESCRIPTION OF THE REFERENCED NUMERALS
Turning now descriptively to the drawings, in which similar reference characters denote similar elements throughout the several views, the figures illustrate the Combination Cuticle Oil Dispenser and Ceramic Cuticle Stone of the present invention. With regard to the reference numerals used, the following numbering is used throughout the various drawing figures.
10 Combination Cuticle Oil Dispenser and Ceramic Cuticle Stone of the present invention 12 user 14 cuticle of 12 16 porous ceramic cuticle stone 18 body of 10 20 cavity of 16 22 cuticle oil 24 cap 26 oil conduit 28 reservoir 30 gasket 32 filter 34 refill plug 36 first end of 18 38 second end of 18 40 angular distal surface of 16
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The following discussion describes in detail one embodiment of the invention. This discussion should not be construed, however, as limiting the invention to those particular embodiments, practitioners skilled in the art will recognize numerous other embodiments as well. For definition of the complete scope of the invention, the reader is directed to appended claims.
FIG. 1 is an illustrative view of the present invention in use. Shown is the user 12 treating her cuticles with the cuticle oil dispenser pen 10 of the present invention. Moisturizing cuticle oil 22 is delivered through a channel 20 into the porous ceramic cuticle stone 16 to the cuticle 14 . A reservoir is contained within the body 18 of the pen to store the oil therein.
FIG. 2 is an illustrative view of the present invention. Shown is the cuticle oil dispenser pen 10 having a cap 24 that snaps onto the first end 36 of the body 18 to protect the porous ceramic cuticle stone 16 which has an angular distal surface 40 .
FIG. 3 is a side view of the cuticle oil dispenser pen 10 of the present invention. Shown is the cap 24 snapped onto the body 18 to protect the porous ceramic cuticle stone 16 .
FIG. 4 is a side view of the cuticle oil dispenser pen 10 of the present invention. Shown is the oil conduit 26 that transfers the cuticle oil from the reservoir 28 through the channel 20 into the porous ceramic cuticle stone 16 .
FIG. 5 is a side sectional view of the cuticle oil dispenser pen 10 of the present invention. Shown is the assembly of delivery means of the cuticle oil 22 from the reservoir 28 through a filter 32 and into the conduit 26 . A gasket 30 is provided to prevent leakage from the reservoir 28 .
FIG. 6 is an exploded side sectional view of the cuticle oil dispenser pen 10 of the present invention. Shown is the assembly of delivery means of the cuticle oil 22 from the reservoir 28 in the body 18 through a filter 32 and into the conduit 26 which passes through the channel 20 into the porous stone 16 . A gasket 30 is provided to prevent leakage from the reservoir 28 and a refill plug 34 disposed on the second end 38 of said body 18 to provide access to the reservoir 28 for refilling the oil 22 .
FIG. 7 is an illustrative view of the cuticle oil dispenser pen 10 of the present invention in use. Shown is the user 12 applying cuticle oil 22 to the cuticle 14 during treatment with the porous ceramic cuticle stone 16 .
FIG. 8 is a detailed illustrative view of the cuticle oil dispenser pen 10 of the present invention in use. Shown is the user 12 applying cuticle oil 22 to the cuticle 14 during treatment with the porous ceramic cuticle stone 16 .
It will be understood that each of the elements described above, or two or more together may also find a useful application in other types of methods differing from the type described above.
While certain novel features of this invention have been shown and described and are pointed out in the annexed claims, it is not intended to be limited to the details above, since it will be understood that various omissions, modifications, substitutions and changes in the forms and details of the device illustrated and in its operation can be made by those skilled in the art without departing in any way from the spirit of the present invention.
Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention. | A cuticle oil dispenser pen that simplifies the process of cuticle treatment by dispensing moisturizing cuticle oil while cutting and smoothing the cuticle with the associated porous ceramic cuticle stone. | 0 |
BACKGROUND AND SUMMARY OF THE INVENTION
The invention relates to a wiper arm for a system for wiping windows, and more particularly for high-speed rail vehicles.
Numerous wiping arrangements have become known, particularly for motor vehicles. For example, European Patent Document EP-A-92201935.1 shows a wiping arrangement which comprises a wiper arm made of a composite material.
Nowadays, large-surface windshields are used not only in the automobile industry but also in rail vehicles, particularly in the high-speed operation, as, for example, in the case of the ICE (Intercity Railroad) of the Deutsche Bahn AG (German Railroad Corporation). Such windshields provide the required large and good field of vision for the driver of the traction vehicle.
Because of the high traveling speed, special problems occur in the operation with respect to wiping arrangements for wiping the front and rear windows of high-speed rail vehicles. Thus, the aerodynamic lift-off forces of conventional wiper arm bodies, for example, of the wiper arrangement according to European Patent Document EP-A-92201935.1, rise considerably at high traveling speeds, particularly above 120 km/h, so that the wiper blades of the wiper blade arrangement lift off the windshield during the ride.
In order to ensure a sufficient press-on force of the wiper blade, fastened to the wiper arm body and wiper arm, onto the windshield also at high speeds, wind deflector plates have been arranged on the arms and/or wiping blades of the arrangement known so far. The wind deflector plates counteract the lift-off forces which occur at higher vehicle speeds and reduce the press-on force onto the wiper blade.
However, it was a disadvantage of such deflector plates that they considerably restricted the field of vision of the traction vehicle driver and the effectiveness could not be ensured under all possible approach flow conditions. Furthermore, the solutions were very expensive and required high implementation cost because a large number of component parts had to be assembled to form a wiper arm arrangement.
It is therefore an object of the invention to provide a wiper arm for a wiper arm arrangement for wiping windows, particularly in the case of high-speed rail vehicles, to overcome the above-described problems of the state of the art.
In particular, a wiper arm is to be provided wherein the lift-off forces can be kept low also at high traveling speeds and simultaneously a field of vision for the traction vehicle driver is not reduced under unfavorable weather conditions. In addition, a solution is endeavored at reasonable cost.
According to the invention, these objects are achieved in that the wiper arm body of the wiper arm, over its whole length, has essentially a cross-sectional shape with a first curvature facing the windshield and a second curvature facing away from the windshield. The second curvature is smaller than the first curvature.
In such an embodiment of the wiper arm body, the overspeeds and therefore the vacuums occurring on the side of the wiper arm body facing the windshield cause a press-on force which increases with the traveling speed and which counteracts the aerodynamic negative lift forces. As generally in aerodynamics, a curvature in the present patent application is the characteristic of a cross-section which is the result of a curving, thus, of the deviation from a straight line from the nose to the end edge which represents the connection of the center points of circles placed in this cross-section and touching its outer contour.
In an advantageous embodiment of the invention, the curvatures are constructed such that the press on force, on the wiper blade fastened to the wiper arm body, in the whole traveling speed range of the high-speed vehicle up to speeds of 400 km/h, exceeds the aerodynamic lift-off forces of the wiper arm from the windshield. At both ends of a motor car or of a railway engine, the effectiveness of the present invention is independent of the alignment with respect to the traveling direction.
It is particularly advantageous for the curvatures to be selected such that the press-on force, on the wiper blades arranged on the wiper arm which occurs at different traveling speeds, assumes an essentially constant value.
In a first embodiment of the invention, the wiper arm body is a solid body.
As an alternative, the wiper arm body may also be designed as a hollow body. This advantageously permits the arrangement of lines inside the hollow body. An example are the supply lines for the spraying water supply.
The wiper arm body according to the invention expediently consists of a fiber composite, which permits the saving of a considerable amount of weight.
In order to ensure a sufficient flexural strength and resistance to bending in the case of wiper arm bodies made of such fiber composites, it is advantageous for the wiper arm body to have fibers which extend in the longitudinal direction as well as diagonally oriented fibers which provide a sufficient shearing strength and resistance to shearing.
Carbon fiber composites are used as particularly advantageous composites for the wiper arm body according to the invention.
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 a three-dimensional representation of a wiper arm according to the invention with a connection piece for the drive and a connection piece for the wiper arm;
FIG. 2A is a sectional view along Line 2 A— 2 A in FIG. 1 representing the cross-sectional surface of the wiper arm according to the invention, the wiper arm body being constructed as a solid body;
FIG. 2B is a view of a wiper arm body according to the invention which is constructed as a hollow body.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 illustrates an essentially oblong wiper arm body 1 of a wiper arm according to the invention. The wiper arm body 1 has a central area 3 , which extends essentially along the whole length, as well as end areas 5 , 7 . The end area 5 is used as a connection piece 9 for the wiper blade system which is not shown in FIG. 1 and which carries one or several wiper blades which rests against the windshield. The end piece 7 is constructed as a connection piece 11 for the drive of the wiper arm. In the illustrated embodiment, the two end pieces 5 , 7 are constructed as square connection pieces.
Furthermore, FIG. 1 shows the cross-sectional surfaces in the respective areas, that is, in the end areas as well as in the central area 3 . The cross-sectional surface along Line 2 A— 2 A in FIG. 2A is for a wiper arm body which is constructed as a solid body. The cross-sectional surface 20 has a lower first curvature 24 facing the windshield surface 22 . According to the invention, the first curvature 24 is constructed such that the overspeeds and therefore vacuums occurring on the side of the wiper arm body facing the windshield have the effect that a press-on force is built up which increases with the traveling speed and counteracts the aerodynamic lift-off forces. This ensures that, also at very high speeds of above 120 km/h, particularly in the high-speed range of above 300 km/h, the press-on force of the wiper blades, which are not shown, is sufficiently high. It is particularly preferable for the curvature to be selected precisely such that the press-on force of the wiper blade remains essentially constant over the whole speed range and changes only within very narrow limits. The press-on force of the wiper blade is essentially applied by springs which are not shown.
In the application, as generally in the field of aerodynamics, a curvature is a characteristic of the cross-section which is the result of the curving (that is, the deviation from a straight line) of a line from the nose to the end edge, which represents the connection of the center points of circles placed in the cross-section and touching its outer contour.
In order to ensure the operability of the wiper arm body according to the invention, it is advantageously provided in the illustrated embodiment that the profile be constructed symmetrically with respect to a center line H-H situated perpendicularly on the windshield.
In addition to the first curvature 24 facing the windshield, the cross-sectional surface may have another second curvature 26 which is directed away from the windshield, the second curvature 26 always having a smaller or weaker construction than the first curvature 24 . This results in a negative lift on the wiper arm body when air flows around the wiper arm body, and therefore in a pressing-on of the wiper arm body which is fastened to the connection piece 9 and is not shown.
FIG. 2B shows another variant of the wiper arm body according to the invention.
Components identical to those of the wiper arm body according to FIG. 2A have the same reference numbers in FIG. 2 B.
The second wiper arm also has a first curvature 24 as well as a second curvature 26 . The second curvature 26 always has a smaller and weaker construction than the first curvature 24 . In contrast to the embodiment according to FIG. 2A, the embodiment of the invention according to FIG. 2B involves a hollow body, in whose interior lines, particularly supply lines 30 , 32 , can be arranged. The supply lines may, for example, be the spraying water supply of the corresponding windshield wiper arm.
Although the present invention has been described and illustrated in detail, it is to be clearly understood that the same is by way of illustration and example only, and is not to be taken by way of limitation. The spirit and scope of the present invention are to be limited only by the terms of the appended claims. | A wiper arm for wiping vehicle's windows and having an essentially oblong wiper arm body. The wiper arm body has essentially, along its whole length, a cross-sectional shape which has a first curvature facing the window and a second curvature facing away from the window. The second curvature being smaller than the first curvature. | 1 |
FIELD OF THE INVENTION
[0001] The present invention relates to a removable keyboard attachment for a device. The device may typically include an information device such as a mobile phone or personal digital assistant (PDA).
BACKGROUND OF THE INVENTION
[0002] Most portable devices like mobile phones and personal digital assistants do not have a keyboard for user input. Without a keyboard the method of inputting information to the device is very slow and cumbersome. Accordingly, it is extremely desirable and advantageous for keyboards to be provided for these portable devices.
[0003] Although some attempts have been made to address the need to include a keyboard with such devices, the result has been an assembly which is no longer readily portable. For example, one solution has been to attach a keyboard to the front or lower surface of the device so that the keyboard becomes integral to the device. However, when the keyboard is no longer in use it must be removed from the device and then the user is left with the dilemma as to what to do with the keyboard. Given its size, it is difficult and cumbersome to carry and thus the portability feature of the overall device is lost.
[0004] The present invention seeks to address the above problems.
SUMMARY OF THE INVENTION
[0005] According to a first aspect of the present invention there is provided a keyboard attachment including a keyboard member having a keyboard, electrical connection means for detachably connecting the keyboard to an electronic device and attachment means for detachably mounting the keyboard member to the electronic device, said attachment means enabling attachment and detachment of the keyboard member to the electronic device without any damage thereto.
[0006] Preferably, the keyboard attachment is sized to be substantially the same or of a smaller dimension than the device. Preferably, the keyboard attachment is arranged to overlay a front face of the device when it is attached to the device.
[0007] Preferably, during use of the device, the keyboard attachment is connected to the device by an electrical connection, for example a flexible or ribbon cable connected with mating end connectors.
[0008] Preferably, the keyboard attachment includes means to enable the user to view the screen of the device when the keyboard attachment is positioned to overlay the front face of the device.
[0009] Preferably, the viewing means is an aperture or opening in the keyboard attachment which is aligned with the display screen of the device so that the user can view the display screen through the aperture or opening. The viewing means may also include a transparent portion of the keyboard member.
[0010] Preferably, the keyboard attachment is arranged to be connected to the device via a serial port and connector arrangement, or a universal serial bus (USB) and connector arrangement.
[0011] In a preferred form of the invention, the keyboard attachment is arranged to be pivotably attached to the device or to a frame to which the device is attached. The keyboard attachment is preferably arranged to pivot between an in-use position in which it overlays the front face of the device and an access position in which the keyboard attachment is pivoted to a position away from the device and whereby the user can readily access the front face of the device.
[0012] Locking means is preferably provided between the keyboard attachment or the keyboard and the device or the frame of the device, to enable the keyboard attachment or keyboard to be locked in the in-use position. The locking means preferably prevents accidental pivotable movement of the keyboard attachment or keyboard relative to the device.
[0013] The removable keyboard attachment may additionally include a cover arranged to cover the entire keyboard or alternatively arranged to cover the viewing means so as to provide protection to the display screen of the device.
[0014] The removable keyboard attachment may additionally include a light source to provide light to the device. The light source may run along either longitudinal side of the keyboard attachment.
[0015] The removable keyboard attachment is preferably arranged to be secured to the device using a hinge attachment previously provided to attach a conventional cover to the device.
[0016] Preferably, the keyboard attachment is substantially made of a plastics material. It is lightweight so that when the keyboard attachment is attached to the device to form a combined unit, the combined unit is not overly heavy as compared with the device alone.
[0017] In accordance with another aspect of the invention, there is provided a keyboard attachment for a device having a display screen and at least one input, said keyboard attachment incorporating a keyboard which is arranged to be connected to the device so that the keyboard can be used to provide input to the device, said keyboard attachment including support means arranged to support the device when it is connected to the keyboard attachment and wherein when the device is not in use, the keyboard attachment can be attached to the device to form a combined unit in which the display screen and said at least one input are located adjacent the keyboard attachment.
[0018] Preferably, the support means is arranged so that the device during use is supported so that the display screen of the device can be readily viewed by the user.
[0019] Preferably, the support means includes an inclined rest surface. The support means is preferably movable between a position in which it is at least partially contained within the keyboard member and a position in which it extends thereform.
[0020] The support means may also include a serial port arranged to engage with a mating serial port on the device. In one preferred arrangement the support means includes at least one horizontal retraction member and at least one pivotal support arm pivotally attached to a free end of the at least one horizontal retraction member.
[0021] In accordance with another aspect of the invention there is provided a keyboard attachment for a device having a display screen and at least one input, said keyboard attachment including a keyboard member incorporating a keyboard which is arranged to be connected to the device so that they keyboard can be used to provide input to the device when it is connected to the device and a support means arranged to support the device during use thereof so that the display screen of the device can be readily viewed by the user and wherein the support means is movable between a position in which it is at least partially contained within the keyboard member and a position in which it extends therefrom.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:
[0023] [0023]FIG. 1 is a perspective view of a portable information device with conventional cover attached thereto in a closed position.
[0024] [0024]FIG. 2 is a perspective view of a portable information device incorporating a keyboard attachment with a cover in accordance with a first embodiment of the invention. The cover is shown in the closed position.
[0025] [0025]FIG. 3 is a view similar to that shown in FIG. 2 but with the cover in the open position.
[0026] [0026]FIG. 4 is a view similar to FIGS. 2 and 3 but with the keyboard attachment and cover in the access position.
[0027] [0027]FIG. 5 is an assembly view of the device and keyboard attachment with cover as shown in FIGS. 2 to 4 .
[0028] [0028]FIG. 6 is a side view of a portable information device, with a keyboard attachment and cover in an open or access position.
[0029] [0029]FIG. 7 is an enlarged perspective view showing the locking studs of the keyboard attachment and the corresponding apertures in the side wall of the device.
[0030] [0030]FIG. 8 is a perspective view of the hinge of the cover and the detent mechanism.
[0031] [0031]FIG. 9 is a side view of the device with a part of the side wall removed so that the hinge receiving aperture can be viewed.
[0032] [0032]FIG. 10 is a front view of a portable information device with a keyboard attachment in accordance with a second embodiment of the invention attached thereto.
[0033] [0033]FIG. 11 is a side view of the device and keyboard attachment shown in FIG. 10.
[0034] [0034]FIG. 12 is a side view of a keyboard attachment and device in accordance with a third embodiment of the invention.
[0035] [0035]FIG. 13 is a plan view of the keyboard attachment and device shown in FIG. 12.
[0036] [0036]FIG. 14 is a side view of the keyboard attachment and device shown in FIG. 12.
[0037] [0037]FIG. 15 is a top view of the keyboard attachment and device shown in FIG. 12 and showing schematically the retraction of the keyboard attachment into the device.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0038] [0038]FIG. 2 illustrates a device 10 to which a keyboard attachment 12 , in accordance with a first embodiment of the invention, is pivotally attached. The keyboard attachment 12 , in this embodiment, includes a substantially planar keyboard member 14 and a protective cover 16 . Both the keyboard member 14 and protective cover 16 are connected to the device 10 in a manner whereby they can be separately pivoted relative to the device 10 . This form of connection enables the protective cover 16 to move between a closed position, as shown in FIG. 2, to an open position, as shown in FIG. 3. Similarly, the keyboard member 14 is connected to the device 10 so that it can be moved between an in-use position, as shown in FIGS. 2 and 3, and an access position, as shown in FIG. 4. In the in-use position the keyboard member 14 overlaps the front face of the device 10 . In the access position, the keyboard member 14 is located away from the device 10 so that the device 10 can be readily accessed by the user.
[0039] The device 10 includes a display and touch screen 18 and may also include an input area 20 . The input area 20 contains inputs through which a user can provide simple input to the device 10 . The inputs may include an on/off button and up/down navigation buttons. However, other inputs in the form of simple ‘quick launch’ keys, 4-way navigation buttons, a plurality of alpha numeric or numeric buttons may also be included. However, to simplify the present Figures, only five such inputs 21 have been shown in the input area 20 .
[0040] The device 10 has a serial port 22 which enables the device 10 to be electrically detachably connected to the keyboard member 14 . The serial port 22 of the device 10 is located in the bottom side 23 of the device 10 . This facilitates ready attachment of the device 10 to the keyboard member 14 via a serial port connector 24 located in the bottom side 25 of the keyboard member 14 .
[0041] It is envisaged that the connection between the keyboard member 14 and the device 10 would be made via ribbon cable or other flexible cable having appropriately configured end connectors arranged to engage with the respective serial ports of the keyboard member 14 and the device 10 .
[0042] The connection between the keyboard member 14 and the device 10 may also be achieved using a retractable connector. The connector would be retracted from the device 10 before use and would preferably, for aesthetic reasons, remain hidden from view when not in use. The connector would be connected to the port after the keyboard 14 is moved to a position in which it overlays the device 10 .
[0043] Alternatively, connection between the keyboard member 14 and the device 10 may be achieved using a spring loaded connector. When the keyboard 26 is in an in-use position, the user pulls the spring loaded connector in an outward direction from the device 10 so as to release the connector. The connector is then snapped onto the connection port. The connector is preferably hidden from view when not in use.
[0044] The connection between the keyboard member 14 and the device 10 may also be achieved via a wireless connection. For example, an infra red connection. Bluetooth technology may also be incorporated.
[0045] Although, the serial ports of the respective device 10 and keyboard member 14 are envisaged to be located in their respective bottom sides 23 , 25 , other positionings of the serial ports are envisaged. It is proposed however that the serial ports of the respective device 10 and keyboard member 14 be located adjacent to one another when the device 10 is in use so that the flexible or ribbon cable used to connect them can be kept at a minimum.
[0046] Alternatively, the ribbon cable could be located at the top of the device 10 . This would have the advantage that the distance between the keyboard attachment 12 and the device 10 would always be kept at a minimum, regardless of positioning of the keyboard member 14 .
[0047] The keyboard member 14 is sized to be substantially the same planar dimension as the device 10 . Adjacent its bottom side 25 , the keyboard member 14 incorporates a keyboard 26 . The keyboard 26 would preferably include all the features of a standard keyboard and is sized so that it is readily used by the user.
[0048] The keyboard member 14 also includes an opening or aperture 28 , which as shown in FIGS. 3 and 4, is substantially rectangular. The opening 28 is positioned so that when the keyboard member 14 is in the in-use position, the opening 28 is coaxially aligned with the display screen 18 of the device 10 . Consequently, when the keyboard member 14 is in the in-use position, the user will have proper sight and full access to the display and touch screen 18 of the device 10 .
[0049] The cover 16 may be made of a transparent material so that the screen 18 can be viewed even when the cover 16 is in the closed position. It will however be appreciated that the user will have to open the cover 16 to access the display and touch screen 18 .
[0050] When a user wishes to use the keyboard 26 to input to the device 10 , the keyboard member 14 is pivoted to a position wherein it overlays the front face of the device. In this in-use position the inputs 21 of the input area 20 of the device 10 are covered so as to prevent use by the user. However, the user still has full access to the touch and display screen 18 . The user connects the keyboard member 14 to the device 10 using the connector 24 and then the device 10 is ready for use.
[0051] When the device 10 is not in-use, the connection between the keyboard member 14 and device 10 can be disconnected. The protective cover 16 can then be pivoted to the closed position so that it overlays the display screen 18 . The protective cover 16 may be sized so that when it is in the closed position it only covers the opening 28 so as to protect the screen 18 . Alternatively, the cover 16 may be sized that it covers the entire keyboard member 14 when in the closed position so as to provide protection for the keyboard 26 . In this manner, the protective cover 16 would act to protect the entire front face of the device 10 in a fashion similar to that of the conventional protective cover illustrated in FIG. 1.
[0052] The keyboard member 14 includes a locking member 80 for locking the keyboard member 14 to the device 10 . The locking member 80 , as best illustrated in FIGS. 5 and 7, includes a pair of locking studs 82 mounted on a catch member 84 . The locking studs 82 are arranged to fit with corresponding apertures 86 formed in the bottom side 23 of the device 10 . The studs 82 are configured so that they engage into the apertures 86 when the keyboard member 14 is positioned to overlay the front face of the device 10 . The locking member 80 is unlocked to free the keyboard member 14 for pivotal movement by deflecting the catch member 84 away from the bottom side 23 of the device 10 , a sufficient distance to remove the studs 82 from their respective apertures 86 .
[0053] The keyboard member 14 and protective cover 16 are pivotally connected to the device 10 by removing the conventional cover 100 (shown in FIG. 1) and then by pivotally connecting the cover 16 and keyboard member 14 to the existing pivot aperture 40 in the side wall 23 a of the device 10 .
[0054] As best shown in FIGS. 5, 8 and 9 , the cover 16 includes a hinge plate 30 which includes a hinge pin 32 and a detent mechanism 34 mounted on an inner face 30 a thereof. The hinge pin 32 and detent mechanism 34 are arranged to extend through an aperture 36 formed in a hinge plate 38 located on the keyboard member 14 and to locate within the aperture 40 formed in the side wall 23 a of the device 10 . The detent mechanism 34 , aperture 36 and aperture 40 of the device 10 are arranged so that the cover 16 and keyboard member 14 are prevented from inadvertently falling back over the device 10 once they have been pivoted to the access position by the user.
[0055] The protective cover 16 and keyboard member 14 are preferably made from lightweight materials such as a plastics material. This means that the additional weight of the device 10 with the keyboard attachment 12 is not that high. It will be appreciated that it is desirable to maintain the combined unit weight to a minimum. It will also be appreciated that the configuration of the keyboard member 14 and protective cover 16 is such that it does not increase the planar dimension of the device 10 , although there is necessarily some increase in the thickness of the combined unit as opposed to the thickness of the device 10 alone.
[0056] The device 10 with pivotally connected keyboard attachment 12 is particularly advantageous because the user is provided with a complete keyboard 26 which the user can use to provide input to the device 10 . The combined unit and the flexible or ribbon connector 24 required to connect the keyboard attachment 14 to the device 10 can be readily carried by the user, thus there is no change in the portability of the device 10 . It will also be appreciated that the pivotal connection between the cover 16 , keyboard member 14 and the device 10 is such that the keyboard member 14 and cover 16 can be readily removed therefrom without damage thereto if required. Additionally, the keyboard member 14 and protective cover 16 can be pivoted to the access position where after the device 10 can still be connected via the serial port to a standard keyboard. This means that the user has the option to use the keyboard 26 on the keyboard member 14 , use the inputs 21 on the input area 20 or alternatively, when in an office environment, still attach the device 10 to a standard sized keyboard if required.
[0057] It is envisaged that the underside of the protective cover 16 and/or the underside of the keyboard member 14 may be provided with a light source so that when the cover 16 is in the open position, as shown in FIG. 3, the cover 16 can provide light to better view the display screen 18 . Alternatively, when the cover 16 and keyboard member 14 are both in the access position the light source from the underside of the keyboard member 14 could also be used to better view the display screen 18 of the device 10 .
[0058] Although the above embodiment has been described with both a keyboard member 14 and a protective cover 16 it is envisaged that the protective cover 16 may not be included. The keyboard member 14 may not include a mechanism for providing protection to the display screen 18 of the device 10 , or alternatively, may include a snap fit cover or other component for covering the opening 28 of the keyboard member 14 so as to protect the screen 18 .
[0059] The protective cover 16 could also be formed as a mini magnifying glass. This would enable the contents of the display screen 18 to be enlarged.
[0060] The protective cover 16 may also be formed so as to include an internal aperture or a slot for holding a photo or the like.
[0061] [0061]FIGS. 10 and 11 illustrate a second embodiment of the invention. In accordance with this second embodiment, the keyboard attachment 12 ′ is of substantially the same or slightly smaller dimension to the front face of the device 10 . The keyboard attachment 12 ′ has an inner surface 12 a ′ which includes a keyboard 26 ′ and an outer surface 12 b ′. The outer surface 12 b ′ acts as a cover when the keyboard attachment 12 ′ is secured to the device 10 so that the inner surface 12 a ′ is located adjacent the screen 18 of the device 10 .
[0062] When the device 10 is not in use, the keyboard attachment 12 ′ can be hingedly connected to the device 10 using the hinges 40 . In this way, the device 10 and keyboard attachment 12 ′ can be readily attached together to form a combined unit. This combined unit can be readily carried by the user.
[0063] The keyboard attachment 12 ′ when attached to the device 10 covers the front face of the device 10 so that the keyboard 26 ′ is located substantially adjacent to the display screen 18 and the inputs 21 on the device 10 . In this manner accidental damage to the display screen 18 is prevented. The keyboard 26 , being located on the inner surface 12 a ′ of the keyboard attachment 12 ′, is also similarly protected.
[0064] It will also be appreciated that the connection between the keyboard attachment 12 ′ and device 10 when attached to form a combined unit is such that it is effectively “sealed”. Accordingly, dirt or other material cannot contact the screen 18 or the keyboard 26 so as to cause damage thereto.
[0065] As best illustrated in FIG. 11, the keyboard attachment 12 ′ includes a support 50 for the device 10 . The support 50 extends from the keyboard attachment 12 ′ and includes an inclined rest surface 52 against which the rear surface of the device 10 can be rested during use. The angle of inclination of the rest surface 52 is such that when the device 10 is rested there against, the display screen 18 of the device 10 is readily viewed by the user. The angle of inclination is preferably about 60° from the horizontal.
[0066] The support 50 may be permanently connected to the keyboard attachment 12 ′ or may be snapped connected or otherwise fitted to the keyboard attachment 12 ′ as required.
[0067] The keyboard attachment 12 ′ is arranged to be connected to the device 10 via a serial port located on one side 25 ′ of the keyboard attachment 12 ′. Alternatively, the serial port may be located in a portion of the support 50 or another extension of the keyboard attachment 12 ′. In either case, the serial port located in the extension or the support 50 would be arranged to be electrically connected to the keyboard attachment 12 ′. The device 10 includes a mating serial port on the bottom side 23 of the device 10 or in an alternative appropriately located position on the device 10 .
[0068] As shown in FIG. 10, and as described above, the keyboard attachment 12 ′ can be hingedly connected to the device 10 via hinges 40 when the keyboard 26 is not in use. However, other means for attaching the keyboard attachment 12 ′ to the device 10 are envisaged. For example, the keyboard attachment 12 ′ may be snap fitted or clipped to the device 10 .
[0069] FIGS. 12 to 15 illustrate a third embodiment of the invention. In this embodiment, the keyboard attachment 12 ″ is of a similar configuration to that described in relation to the embodiment of FIG. 10. However, instead of including a separate support 50 , the keyboard attachment 12 ″ includes a retractable support device support 60 . The retractable support device 60 includes a horizontal retraction member 62 and a pair of pivotable support arms 64 . The horizontal retraction member 62 is arranged for sliding engagement with a portion or opening 65 in the keyboard attachment 12 ″, whilst the pivotable support arms 64 are pivotable between a storage and an in-use position. In the in-use position the pivotable support arms 64 are arranged so that a device 10 can be positioned there against so that the display screen 18 of the device 10 can be readily viewed by the user. When device 10 is not in use, the pivotable support arms 64 can be pivoted to a position where they lie substantially against the retractable member 62 and so that the retractable member 62 together with pivotable support arms 64 can then be retracted into the portion or opening 65 of the keyboard attachment 12 ″. To achieve this, the keyboard attachment 12 ″ will need to include an appropriately configured portion or opening 65 which is arranged to receive the retractable support device 60 when it is not in-use.
[0070] The horizontal retraction member 62 is preferably made from a plastic material, whilst the pivotable support arms 64 are preferably made from a material such as aluminum. This choice of material provides the required strength to each of the components while minimizing the weight thereof.
[0071] The keyboard attachment 12 ″ of FIGS. 12 to 15 attaches to the device 10 in the same manner as described in relation to the embodiment shown in FIGS. 10 and 11.
[0072] It will be appreciated by those skilled in the art that the keyboard attachments described herein can be readily attached and detached from a device by a user without causing any damage to the device. The keyboard attachments described herein in relation to FIGS. 1 to 11 may be fitted to a user's device simply by removing the existing cover. Alternatively, devices may be sold to the user with a keyboard attachment already fitted.
[0073] While the embodiments described herein are preferred it will be appreciated from the specification that various alternatives, modifications, variations or improvements therein which may be made by those skilled in the art are within the scope of the invention, which is defined by the claims. | The invention relates to a removable keyboard attachment for a device such as a mobile telephone or personal digital assistant. The removable keyboard attachment is preferably arranged for pivotal connection to the device. The removable keyboard attachment includes a keyboard so as to enable ready input to the device via the keyboard. | 6 |
CROSS-REFERENCE TO RELATED APPLICATION
This application is a continuation-in-part of the U.S. patent application Ser. No. 11/101,837 filed Apr. 8, 2005.
This application claims the benefit of U.S. provisional patent application Ser. No. 60/725,555 filed Oct. 11, 2005.
BACKGROUND OF THE INVENTION
The present invention relates generally to telescoping gear pumps and motors and, in particular, to a sealing apparatus for such pumps and motors.
Gear pumps and motors provide variable displacement capabilities to some of the most hostile environments. The sealing however on these functionally durable pumps with variable displacement has been an issue. The rotary seals on the gears have to be maintained by even as the internal components shift as the pressure in the pump increases. The gears shift away from the pressure causing many of the other pump/motor technologies with telescoping. The present invention provides a method of and apparatus for eliminating this shortcoming in an otherwise robust technology.
SUMMARY OF THE INVENTION
The rotary pump and motor described in U.S. Pat. No. 815,522 probably worked at the relatively low pressures needed for irrigation. The pressure required to maintain these seals in today's applications however can be extremely high; so high that the seal may fail completely as the components inside the pump/motor begin to distort even slightly under the operating pressure. The rotary seals of the pump/motor according to the present invention have a feature added to them that allows the seal so shift with the other components while maintaining the seal integrity and without compromising the function of the bearings or the bushings needed to bear the load.
DESCRIPTION OF THE DRAWINGS
The above, as well as other, advantages of the present invention will become readily apparent to those skilled in the art from the following detailed description of a preferred embodiment when considered in the light of the accompanying drawings in which:
FIG. 1 is a cross section of an internal gear pump/motor according to the present invention;
FIG. 2 is a perspective view of the internal gear pump/motor shown in FIG. 1 with portions in cutaway;
FIG. 3 is a cross section of an external gear pump/motor according to the present invention; and
FIG. 4 is a perspective view of the external gear pump/motor shown in FIG. 3 with portions in cutaway.
DESCRIPTION OF THE PREFERRED EMBODIMENT
U.S. patent application Ser. No. 11/101,837, filed Apr. 8, 2005, is hereby incorporated by reference. U.S. provisional patent application Ser. No. 60/725,555, filed Oct. 11, 2005, is hereby incorporated herein by reference.
In the drawings, the components of the external gear pump/motor shown in FIGS. 3 and 4 are identified with reference numerals that are twenty numbers higher than the reference numerals for similar components of the internal gear pump/motor shown in FIGS. 1 and 2 .
The internal gear pump/motor 10 shown in FIGS. 1 and 2 includes a hollow seal housing 4 closed at one end by a cap 1 . A tubular rotary seal 3 has a radially outwardly extending flange 3 c including a downwardly facing annular pressure shift surface 3 a and an outwardly facing peripheral shift riser 3 b.
In order to maintain a seal as the pressure develops in the pump/motor 10 , the seal 3 will shift away from the applied fluid pressure toward the low pressure side of the pump/motor. At low pressures this shifting in minimal and prior art telescoping gear pumps/motors can maintain the seals by simply controlling the tolerance at the interface points between the moving parts. However, as the pressure increases the materials of the pump/motor begin to distort. The pressure distortion forms a gap that runs the length of the seal causing the pump/motor to leak internally.
The shift surface 3 a nests into a matching feature in the seal housing 4 so that the amount of radial distortion that can be tolerated before a leak can begin is the width of the shift surface 3 a.
The external gear pump/motor 30 shown in FIGS. 3 and 4 includes a hollow seal housing 24 closed at one end by a cap 21 . A pair of gears 22 having pluralities of meshing teeth are disposed in the hollow teal housing 24 . The hollow seal housing 24 further includes a first port (not shown) and a second port (not shown) that extend between an internal surface and an external surface thereof. One of the ports is connected to a low pressure segment of fluid system (not shown) such as a reservoir or the like, and another of the ports is connected to a high pressure or pressurized segment of the fluid system.
In operation, a shaft of the external gear pump/motor 30 is connected to a prime mover (not shown), such as an electric motor or the like. When the prime mover rotates the shaft, one of the gears 22 rotates and causes the other of the gears 22 to rotate. Fluid is introduced from the fluid system through one of the ports, is trapped between the pluralities of meshing teeth of the gears 22 , and is discharged through the other of the ports. Suitable passages are formed in the hollow seal housing 24 to ensure that the fluid is routed correctly during operation of the external gear pump/motor 30 . Each of the two tubular rotary seals 23 provides a rotating seal between each of the gears 22 and inner surfaces of the hollow seal housing 24 to ensure the integrity of the cavity of the external gear pump/motor 30 . The external gear pump/motor 30 in accordance with the present invention requires only the tubular rotary seals 23 to maintain a seal and allow for efficient operation of the extending gear pump/motor 30 . Each of two tubular rotary seals 23 has a radially inwardly extending step 23 c including an annular pressure shift surface 23 a and an outwardly facing peripheral shift riser 23 b . The steps 23 c face one another and cooperate to permit radial distortion before a leak can begin.
In accordance with the provisions of the patent statutes, the present invention has been described in what is considered to represent its preferred embodiment. However, it should be noted that the invention can be practiced otherwise than as specifically illustrated and described without departing from its spirit or scope. | Rotary seals in a telescoping gear pump/motor a feature that allows the seal to shift radially relative to other components while maintaining the seal integrity and without compromising the function of the bearings or the bushings needed to bear the load. | 5 |
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