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[0001] This application is a Divisional application based on U.S. application Ser. No. 11/585,924 filed Oct. 25, 2006, which claims priority under 35 USC §119 (a)-(d) to Indian Application No. 1537/DEL/2005 filed Oct. 25, 2005.
FIELD OF THE INVENTION
[0002] The present invention relates to a recombinant 12 kDa protein useful for the detection of respiratory allergies. The invention particularly relates to detection of the respiratory allergies caused by fungal spores and grass pollen using the said protein.
BACKGROUND OF THE INVENTION
[0003] The term “allergy” coined by Von Pirquet (1906) is defined as altered immunologic reactivity to foreign particles. The foreign agents causing altered immunologic reactivity are called allergens, which includes a broad spectrum of substances e.g. proteins, glycoprotein, lipoproteins, etc, derived from diverse sources such as pollens, fungal spores, insects, dust mites, animal danders, foods, etc. Pollen grains and fungal spores are the main constituents of the aerospora. They are significant cause of allergic diseases afflicting more than 25% of the atopic subjects. These foreign substances can trigger the release of mediators from immune system leading to inflammatory and other allergic reactions.
[0004] Allergy is detected clinically by skin testing and ELISA. The fungal extracts generally used for skin testing are complex mixture of proteins, carbohydrates, pigments, toxins, etc. They contain both relevant and non-relevant components that might sensitize the patient and eventually evoke anaphylaxis. Another factor that adds complexities to diagnosis of fungal allergy, is cross-reactivity among allergens from different sources. Cross reactivity is due to the presence of similar protein components and/or epitopes shared by different fungal species. Studies on cross reactivity have shown antigenic/allergenic relationship among species of fungi such as Curvularia, Cladosporium, Fusarium, Peneillium and Aspergillus [ 1]. Curvularia lunata has been shown to be an important allergy causing fungi also responsible for life threatening Allergic bronchopulmonary aspergillosis (ABPA) like symptoms in many patients [2].
[0005] Due to complexities involved in standardizing the large number of extracts, use of recombinant allergens have now begun for diagnostic purposes, e.g. use of rAsp f 1, rAsp f 3 and rAsp f 6 has made it possible to diagnose differentially between ABPA and A. fumigatus sensitized asthmatics, (Hemmann, et al). For three reasons, diagnosis with recombinant allergen is advantageous over heterogeneous crude allergen extract [3,4]. First, it provides pure, standardized and consistent allergen preparations. Secondly, skin tests with these preparations are free of false positive or false negative i.e. non-specific reactions. Thirdly, it allows substantial evidence of patient's specific reactivity against a particular allergen and thus helps in better understanding of the disease causing components. Isolation and purification of recombinant cross-reactive allergens would lead to a better and easier way of diagnosis. Since, using cross-reactive allergens would reduce the number of extracts used for skin testing [5]. The recombinant form of these cross-reactive allergens would improve sensitivity of such diagnosis [6]. An important criterion for such applications is that there should be equivalent immuno-biochemical properties of the recombinant allergen and its native counterpart. Many recent reports have suggested the same e.g. Grendelmeier P S et al have reported [7] that Art v 1 restores its properties after making it recombinant. Similarly, a recent report [8] from Jeong K Y group have shown the similar properties of recombinant and native Bla g 7, an allergen from German cockroach.
OBJECTS OF INVENTION
[0006] The main object of the invention is thus to provide a recombinant 12 K-Da protein useful for the detection of respiratory allergies.
[0007] Another object of the present invention is to provide a method for detection of respiratory allergies using the said recombinant 12 kDa protein.
[0008] Still another object of the invention is to provide novel primers for sequencing and expression of the disclosed 12 kDa protein by recombinant methods.
[0009] Yet another object of the invention is the expression and purification of recombinant 12 kDa protein.
SUMMARY OF THE INVENTION
[0010] The invention discloses the detection of respiratory allergies using a recombinant 12-kDa protein. The present invention is based on the fact that there is a need of a single cross-reactive protein capable of replacing large number of extracts used for detection of raised IgE levels in allergy by ELISA, immunobloting and the likes. It is further based on the realization that such a cross-reactive protein will reduce the number of pricks, a patient gets during allergy skin testing, thus providing a single representative of large number of allergen extracts used. It is further realized that production of such a protein by recombinant methods can lead to its availability in pure form and bulk amounts required for routine diagnosis. In extension to the fact mentioned above, the resemblance of such a recombinant protein to its native form is an additional benefit forming the basis of its use clinically.
[0011] Accordingly, the present invention provides a recombinant 12 kDa fungal protein useful for detection of respiratory allergies, the said protein exhibiting the following characteristics:
a) a protein having mRNA sequence of SEQ ID 1 (NCBI ACCESSION NO. AY034827) and coding sequence (CDS) of SEQ ID 2 (NCBI ACCESSION NO. AY034827), b) the translated protein sequence having SEQ ID 3 (NCBI ACCESSION NO. AAK67492), e) resolves on SDS-PAGE as a protein with molecular weight 12 kDa, d) having an iso-electric point of 9.5 as determined by iso-electric focusing, e) having UV-visible absorbance peaks at 411 nm and 511 nm, f) with CD spectra having characteristic double minima in the range of 210 nm-220 nm signifying high alpha helical content, g) with melting temperature in the range of 57-58° C. as found by CD spectra, h) is recognized by commercially available and raised specific polyclonal antibodies, i) is having allergenic reactivity in patient's sera and which is three to four times that of healthy controls, as confirmed by ELISA and immunoblot, j) is cross-reactive among grasses and fungi as confirmed by ELISA, immunoblot and ELISA k) is having comparable activity with its native form purified from fungus as confirmed by SDS-PAGE, immunoblot, ELISA, ELISA inhibition, absorbance and CD spectra,
[0023] The disclosed recombinant 12-kDa protein is highly cross-reactive in grasses and fungi as tested by ELISA inhibition, EC 50 required for 50% loss of IgE binding activity is in the range of 1-1.5 ng.
[0024] In an embodiment of invention, the cDNA library of fungus was constructed in commercially available λZAP vector and the like.
[0025] In still another embodiment, the fungus for cDNA library was selected from Curvularia lunata [MTCC 2030], Alternaria alternate [MTCC 1362] , Epicoccum nigrum [ MTCC 2129] and Fusarium solani [MTCC 1756].
[0026] In yet another embodiment of the invention, the screening of cDNA library for locating the protein of interest was carried out with pooled sera of patients allergic to Curvularia lunata and the like.
[0027] In still another embodiment of the invention, the mRNA sequence SEQ ID 1 (NCBI ACCESSION NO. AY034827) and its coding sequence (CDS) SEQ ID 2 (NCBI ACCESSION NO. AY034827) were obtained using known primers.
[0028] In still another embodiment of the invention, the protein sequence obtained by translating the coding sequence SEQ ID 3 (NCBI ACCESSION NO. AAK67492) was computationally compared with known sequences available in databank using ClustalW and BLAST and the like.
[0029] In yet another embodiment of the invention, novel primers of SEQ ID NOS. 4 and 5 were designed for sub-cloning the SEQ ID NO. 2.
[0030] In still another embodiment of the invention, the protein of SEQ ID 3, was expressed in E. coli prokaryotic expression vector and the like.
[0031] In still another embodiment of the invention, the purification of the recombinant protein was carried out using two steps comprising metal affinity chromatography and Gel exclusion chromatography and the like.
[0032] In yet another embodiment of the invention, the said protein resolved as 12 kDa protein on SDS-PAGE, was recognized by commercial and raised antibodies.
[0033] In still another embodiment of the invention, the allergenic properties of the recombinant protein were assessed by ELISA, immunoblot, ELISA inhibition and the like.
[0034] In still another embodiment of the invention, the native form of the disclosed allergen was purified using two-step method comprising cation exchange chromatography using CM cellulose and the like and gel exclusion chromatography using Sephadex G50 and the like.
[0035] In still another embodiment of the invention, the disclosed recombinant allergen was compared to its native counterpart by physiochemical viz. CD and absorption spectra and like and immunological methods viz. immunoblot, ELISA, ELISA inhibition and the like.
[0036] In still another embodiment of the invention, the cross-reactivity of the disclosed recombinant allergen was compared with fungi viz. A. alternata, E. purpurascens, F. solani, C. albicans and the like by ELISA, Immunoblot, ELISA inhibition and the like.
[0037] In still another embodiment of the invention, the cross-reactivity of the disclosed recombinant allergen was checked with grass pollen viz. Lolium perenne, Poa pretense, Phleum pretense, Imperata cylindrica Pennisetum sp., Rye grass, Zea Mays and Cenchrus and the like by immunoblot, ELISA and ELISA inhibition using pooled and individual allergic sera as well as commercial and raised antibodies against disclosed protein.
BRIEF DESCRIPTION OF THE FIGURES
[0038] FIG. 1 depicts the 12% SDS-PAGE profile of uninduced (Lane 1) and induced (Lane 2) recombinant protein. Lane 3 shows the profile of purified 12 kDa.
[0039] FIG. 2 shows the absorption spectra of purified 12-kDa protein. The prominent absorption peaks were seen at 410 nm, 470 nm and 511 nm.
[0040] FIG. 3 depicts the CD spectra of both recombinant and native form of 12-kDa protein. The equivalent minima and maxima were observed indicating comparable secondary structure.
[0041] FIG. 4 exhibits the immunoblot of both recombinant and native form of 12-kDa allergen with 15 individual patient sera and 4 control healthy sera.
[0042] FIG. 5 shows the IgE specific ELISA with crude extract of Curvularia and both recombinant and native form of 12-kDa protein.
[0043] FIG. 6 depicts the ELISA inhibition of both recombinant and native form of 12-kDa proteins with crude Curvularia extract. Both the forms of 12-kDa protein required comparable amount (i.e. 8 ng for recombinant and 1 ng for native) for 50% inhibition. This indicates the comparable nature of both these forms.
[0044] FIG. 7 exhibits the cross-reactivity of 12-kDa protein with various prevalent Indian and Western grass positive patient sera.
BRIEF DESCRIPTION OF THE TABLES
[0000]
Table 1: ELISA values carried out with 12-kDa allergen with patient sera of fungal positive sera.
Table 2: ELISA values, carried out with fungal negative and grass positive sera. These values show the cross-reactive nature of 12-kDa protein
DETAILED DESCRIPTION OF THE INVENTION
[0000]
1. Total RNA isolation: C. lunata grown in Sabouraud's broth for 4 days was used for isolating total RNA. Fresh CL culture was separated from the medium and washed with diethyl pyrocarbonate (DEPC) treated water. The total RNA was isolated by monophasic solution of phenol and guanidium isothiocyanate using Trizol reagent (Life Technologies). The yield was determined spectrophotometrically and the purity was determined on formaldehyde agarose RNA gel. Seven hundred twenty microgram of RNA was obtained from 3 g of spore mycelial mass (24 μg/100 mg spore mycelial mass).
2. mRNA isolation: Messenger RNA was isolated from total RNA using oligo (dT) cellulose column commercially available. From total RNA, 7 μg mRNA was obtained and cDNA library was constructed using 5 μg mRNA.
3. Construction of cDNA library: A cDNA expression library was constructed in Uni ZAP XR vector commercially available with poly (A)RNA. The cDNA molecules were synthesized by using 50 base oligonucleotide primer and reverse transcriptase. Using commercial primers provided with kit. The cDNA obtained was ligated with Eco R I adapters. The cDNA was digested with Xho I, fractionated and 0.5-2.0 kb fragments were ligated into Uni-ZAP XR vector. The ligation mix was packaged using commercial Gigapack III Gold packaging extract at 22° C. for 2 h. The percentage of non-recombinant background plaques was determined on NZY plates containing IPTG and X-gal. The background of non-recombinant phages was 0.6%. The Escherichia coli strain XL-1 Blue was used as host for amplification and screening of the library. The titer of the library was 1×10 9 .
4. Escherichia coli strain: E. coli XL-1-Blue MRF′ strain is RecA and contained F′ episome, essential for Uni-ZAP XR vector. The F′ episome present in E. coli XL-1-Blue MRF′ strain is required for phage infection and contains (a) enzymatically inactive β-galactosidase gene required for enzyme based non-recombinant selection strategy (b) expresses the genes forming F′ pili found on the surface of the bacteria (c) contains lac repressor gene.
5 . E. coli SOLR strain was used for plating excised phagemids. Ex ASIST™ interference resistance helper phage was used for excision of the pBluescript phagemids from the Uni-ZAP XR vector.
6. Patient's sera: The serum from 10-nasobronchial allergy patients hypersensitive to Curvularia as determined by intradermal tests were collected pooled and used for screening the cDNA library.
7. Screening of cDNA library with patient's sera: The cDNA library was screened by using a pre-absorbed human serum pool with E. coli XL-1 Blue lysate. The phages were used to infect E. coli XL-1 Blue cells and plated on 90 mm NZY agar plate (density 300-400 plaques/plate). Screening was performed using pre-absorbed patient's serum.
8. PCR Amplification and DNA Sequencing: The positive clones were isolated and the phage stock was used to infect E. coli XL-1 Blue cells. The plaques obtained were transferred onto the nitrocellulose filter, presoaked with IPTG. Rescreening was performed using pre-absorbed patient's serum. The cDNA insert in the phage was amplified by polymerase chain reaction with T3/T7 primers. The amplified product was purified using commercial DNA isolation kit. An overnight culture of E. coli XL-1 Blue cells was co-infected with the cloned phage and helper phage to convert the phage into the phagemid. The plasmid DNA was isolated and was used as a template for DNA sequencing using T3/T7 universal commercial primers and sequences submitted to NCBI GENBANK (SEQ ID # 1 and 2).
9. Computational analysis: ORF of one of the positive clone was obtained using DNASTAR program, translated and homology search was done using NCBI-BLAST both at nucleotide and protein level. ORF of the sequence was 327 bp encoding 108 amino acids (SEQ ID # 3) Molecular mass determined computationally was 12 kDa and pI was 9.5.
10. Expression and purification of recombinant form of 12-kDa protein in E. coli : The ORF obtained was amplified using primer SEQ ID # 4 and 5. The PCR product was digested with restriction enzymes, ligated into pET22b+ vector. The plasmid containing the insert was transformed into BL-21 E. coli cells. The his-tagged recombinant 12 kDa protein was purified using Ni-NTA affinity purification with a yield of about 0.5 mg/l of culture and further by gel filtration chromatography. This protein resolved as 12-kDa protein on SDS-PAGE.
11. Purification of native form of 12-kDa protein: The 13-day old C. lunata fungal mat grown in Sabraoud's media was harvested, lyophilized and stored at −20° C. for purification of native form of this 12-kDa protein. The antigens/allergens from Curvularia were extracted 1:20 (w/v) in 50 mM ammonium bicarbonate (NH 4 HCO 3 ) pH-8. The protein concentration was estimated using Lowry's method. Lyophilized protein was dissolved in sodium phosphate buffer and kept for binding with swollen and equilibrated CM-C50 cation exchange resin (Pharmacia) at 4° C. overnight. The elution of protein was carried out using increasing ionic strength of NaCl gradient in phosphate buffer. The protein was eluted using 0.5M NaCl in 20 mM sodium phosphate buffer. The fractions containing 12 kDa protein were loaded on equilibrated Sephadex G-50 column. The activity of the native protein was estimated by both absorption spectra and immunoblot with raised antibody.
12. Comparative Study of recombinant and native forms of 12 kDa:
A. Immunoblot of 12 kDa protein with allergic patient sera: The purified 12 kDa protein were resolved by SDS-PAGE and transferred onto nitrocellulose. The membranes were washed and incubated overnight at 4° C. with 15 individual hypersensitive patient sera. After washing the strips with PBS-Tween20, anti-human IgE peroxidase or protein G peroxidase or anti-rabbit IgG peroxidase were added to the respective blots. After incubation at 37° C., membranes were washed and developed with Diaminobenzidine in acetate buffer. All the patients' sera reacted positively to both the proteins indicating that they are major allergens. B. ELISA of purified 12 kDa protein with allergic patient sera IgE specific ELISA was performed with both the forms of 12-kDa protein (i.e. recombinant and native) using known methods [12] to determine its allergenic potency. Purified protein was coated on microtiter plate in carbonate buffer (pH9.6) and was kept overnight at 4° C. The plate was washed with PBS-Tween20, blocked and incubated overnight with 120 different fungal allergic patient sera. Appropriate healthy individual sera were also used as controls. The plates were washed with and incubated for 3 hrs at 37° C. with anti-human IgE peroxidase conjugated. The color was developed with o-phenylene diamine in sodium citrate buffer. The reaction was stopped after 30 minutes with 50 μl of 5N H 2 SO 4 and absorbance was read at 490 nm in ELISA reader. IgE ELISA value was comparable for the proteins and ranged from 0.6-1.2 C. ELISA inhibition of 12 kDa recombinant protein with crude Curvularia extract For ELISA inhibition study, crude extract and recombinant protein was coated on ELISA plates separately. The plates were washed, blocked and incubated overnight at 4° C. with pre-incubated mixture of sera having different concentration of recombinant protein. The plates were washed and incubated with anti-human IgE peroxidase labeled. The color was developed with OPD and the reaction was stopped with 5N H 2 SO 4 and read at 490 nm in ELISA reader. Around 5 ng of recombinant 12 kDa protein was required to obtain 50% inhibition. ELISA inhibition study indicates that they are having the same allergenic potential. D. Absorption spectra of purified recombinant protein The absorption spectrum of 12 kDa protein was to find the characteristic absorption maxima peaks of heme containing proteins and shows the peaks at 410 nm, 510 nm and 550 nm.
13. Circular dichroism of 12-kDa protein: CD spectra were carried out with 1 mg/ml of each recombinant and native protein in 20 mM phosphate buffer in the far-UV range. Thermal scans in the range of 10-100° C. were also carried out to find the melting temperature (Tm) of recombinant 12 kDa protein.
14. Detection of 12-kDa protein in fungi: Specific IgE ELISA was performed with fungal hypersensitive sera. Purified protein was coated on the plates and incubated overnight at 4° C. in carbonate buffer (pH9.6). The plate was washed with PBS containing 0.05% Tween20, blocked and incubated overnight with each of 118 different fungal allergic patient's sera. Healthy sera from 20 individuals were used as negative control. The plates were washed, incubated for 3 hrs at 37° C. with anti-human IgE peroxidase. After washing, color was developed with o-phenylene diamine and absorbance was read at 490 nm in ELISA reader. The specific IgE values for 12-kDa recombinant protein with 118 fungal allergy patients. The specific IgE values for 12 kDa protein for most of the patients' sera ranged from 0.7-1.6 compared to 20 healthy controls i.e. 0.2-0.3. It was found that patients positive to A. alternata, E. nigrum, F. solani and A. fumigatus showed slightly higher specific IgE values as compared to other fungi. This data highlights the cross-reactive nature of this protein among fungi.
15. 12 kDa protein as a cross-reactive allergen in tropical and temperate grasses:
To establish the presence of r-12 kDa protein in different grasses, ELISA and immunoblot of various Indian and Western grasses was done. Grass extracts used were Lolium perenne, Poa pretense, Phleum pretense, Imperata cylindrica, Pennisetum sp., Rye grass, Zea Mays and Cenchrus . Protein extracts were coated on microtiter plate and ELISA was done as earlier, using antibodies raised in mouse. Anti-mouse IgG peroxidase labeled as secondary antibody. These extracts were separated on SDS-PAGE and transferred on nitrocellulose membrane and immunoblot performed as earlier using antibody raised in mouse against r 12 kDa protein. It showed the presence of r-12 kDa protein in grass extracts viz. Lolium perenne (Lol p), Poa pretense (Poa p), Phleum pretense (Phl p), Imperata cylindrica (Imp c), Pennisetum sp., Zea Mays and Cenchrus . Further, allergenicity of recombinant 12 kDa protein is demonstrated in FIG. 6 , which shows the immunoblot of recombinant 12 kDa protein with different grass positive sera. It was seen that Lol p, Phl p and Poa p showed higher immunoreactivity on blot followed by Imp c, Zea mays, Pennisetum and Cenchrus . This result demonstrates recombinant 12 kDa protein is an important cross-reactive allergen present in Indian and western grasses.
[0000]
TABLE 1
No. of
patients
Specific IgE value
S. No
Fungus
screened
range
1
Alternaria alternata
20
0.8-1.2
2
Cladosporium herbarum
11
0.7
3
Fusarium solani
9
0.8
4
Epicoccum nigrum
7
0.6-1.2
5
Curvularia lunata
20
0.9-1.6
6
Aspergillus fumigatus
15
0.8-1.0
7
Rhizopus sp.
10
0.8
8
Mucor sp.
8
0.6
9
Pencillium citrinum
11
0.7
10
Candida albicans
7
0.7
11
Healthy controls
20
0.2-0.3
[0000]
TABLE 2
Specific IgE
value to the
Patient
Age/
Skin test reactivity
claimed 12-KDa
No.
Sex
Fungi
Grasses
rCytc
protein
1
M/60
−ve
Cen++±, Cyn++±,
+++
0.762
Imp++, Pen +±,
2
F/28
−ve
Cen+++, Cyn++±,
+++
0.718
Pen+, Imp++
3
M/27
−ve
Cen++, Imp++, Pen+,
++±
0.682
Cyn+
4
F/31
−ve
Cen++, Imp+±,
+±
0.318
Pen+++
5
M/29
−ve
Cen++±, Cyn+++,
++±
0.610
Imp++, Pen +±
6
F/24
−ve
Cen+, Cyn ±, Imp ±,
+±
0.412
Pen+
7
F/23
−ve
Cen+, Cyn±, Imp±,
+±
0.371
Pen+
‘+’ = severity of the skin test reaction
EXAMPLES
[0071] The following examples are given by way of illustration and therefore should not be construed to limit the scope of the present invention.
Example 1
Total RNA Isolation
[0072] One hundred mg of 4 day old CL spore mycelium mass was crushed under liquid nitrogen to obtain a fine paste. Added 1 ml of TRI zol reagent and crushed again. The paste was allowed to thaw at RT and 0.2 ml of chloroform was added to it. After gentle shaking, it was incubated for 3 m at RT and centrifuged at 12000 rpm for 15 m at 4° C. The upper aqueous layer was separated and 0.5 ml isopropanol was added and kept at −20° C. for overnight. It was centrifuged at 12000 rpm at 4° C. The pellet was washed with 75% ethanol followed by centrifugation at 7500 rpm at 4° C. The pellet obtained was air dried and dissolved in 0.5% SDS. The quality of total RNA was checked on formaldehyde gel.
Example 2
mRNA Isolation
[0073] From purified total RNA, double oligo (dT) selection was performed to obtain poly (A) mRNA for cDNA library construction. The concentration of total RNA was adjusted to 0.55 μg/μl with DEPC treated DW and the volume was made up to 640 μl. The oligo dT was washed with 1.5 ml washing buffer 1 (supplied with the kit). The salt concentration of the RNA sample was adjusted to 0.5 M by adding 64 μl of 5 M NaCl and was allowed to hybridize at RT for 10 m.
[0074] The unbound RNA was expelled and the column was washed with 1.5 ml of washing buffer 1 followed by washing with buffer 2 (supplied with the kit). The poly(A) mRNA was eluted with 0.5 ml preheated (65° C.) DEPC treated DW. To the eluted 500 μl mRNA, 2 μl of 50 μg/ml glycogen, 50 μl of 7.5 M ammonium acetate and 1000 μl of chilled ethanol were added. Precipitation of RNA was carried out at −20° C. for overnight. The sample was centrifuged at 3000 rpm for 30 m at 4° C. The pellet obtained was washed with 75% ethanol and centrifuged at 3000 rpm for 10 m at 4° C. The pellet was dissolved in 15 μl of DEPC treated DW.
Example 3
Construction of cDNA Library
[0075] The cDNA library was synthesized using Stratagene ZAP-cDNA Gigapack III Gold cloning kit. It uses a hybrid oligo dT linker primer that contains a Xho I restriction site. Messenger RNA is primed in the first strand synthesis with the linker primer. All the reagents used were provided by commercial cDNA synthesis kit. The various steps involved in the construction of the library are described below:
[0076] First strand cDNA: Messenger RNA was used as template to synthesize first strand cDNA. The reaction mixture contained 5 μg mRNA, 5 μl of 10× first strand buffer, 3 μl of 10 mM first strand methyl nucleotide mixture, 2 μl of linker primer (1.4 μg/μl) and 1 μl of RNase block (Ribonuclease inhibitor 400 U/μl) in 50 μl volume. The reaction mixture was incubated for 10 m at RT and 1.5 μl of reverse transcriptase (Moloney murine Leukemia virus reverse transcriptase, 50 U/μl) was added. The reaction was carried out at 37° C. for 1 h.
[0077] Second strand synthesis: To the first strand mix, 20 μl of 10× second strand buffer, 6 μl of second strand dNTP mixture (10 mM), 114 μl autoclaved DW, 2 μl of RNase (1.5 U/μl) and 11 μl of DNA polymerase I (9.0 U/μl) were added in a total volume of 200 μl. The reaction was carried out at 16° C. for 2.5 h and was kept on ice.
Example 4
Blunting the cDNA Termini
[0078] To the second strand mix, 23 μl of dNTP mix (2.5 mM) and 2 μl of cloned pfu DNA polymerase (2.5 U/μl) were added. The reaction was carried out at 72° C. for 30 m. After the completion of the incubation, 200 μl of pre saturated phenol pH-8.0: chloroform: isopropanol was added. It was mixed at RT and the upper aqueous layer was transferred into a fresh tube. To the tube, equal volume of chloroform was added and mixed. The sample was then centrifuged and the upper aqueous layer was transferred to fresh microcentrifuge tube. The DNA was precipitated by adding 20 μl of 3 M sodium acetate and 400 μl of 100% ethanol at −20° C. for overnight.
Example 5
Ligating the EcoR I Adaptors
[0079] The DNA pellet obtained was washed with 70% ethanol and dried. To this, 1 μl of 10× ligase buffer, 1 μl of 10 mM rATP and 1 μl of T4 DNA ligase (40 U/μl) were added. The reaction was carried out at 8° C. for overnight.
Example 6
Phosphorylating the EcoR I Ends
[0080] After inactivating the ligase at 70° C. for 30 m, 1 μl of 10× ligase buffer, 2 μl of 10 mM rATP, 6 μl of autoclaved DW and 1 μl of T4 polynucleotide kinase (10 U/μl) were added. The reaction was carried out at 37° C. for 30 m.
Example 7
Digesting with Xho I
[0081] The kinase was inactivated at 70° C. for 30 m and 28 μl of Xho I buffer supplement and 3 μl of Xho I (40 U/μl) were added. The tube was incubated at 37° C. for 1.5 h. After the completion of the reaction, 5 μl of 10×STE buffer and 12 μl of 100% ethanol were added. The DNA was precipitated at −20° C. for overnight.
Example 8
cDNA Fractionation
[0082] The DNA pellet was washed, dried and resuspended in 14 μl of 1×STE buffer followed by addition of 3.5 μl of the column loading dye was added. The drip column was packed using Sepharose CL-2B gel filtration medium and washed twice with STE buffer. After this, the cDNA sample was gently loaded without disturbing the resin. The column was washed with STE buffer and cDNA sample eluates were collected. From each fraction, 5 μl of sample was aliquoted and electrophoresed on an alkaline agarose gel.
Example 9
Ligating cDNA into the Uni-ZAP XR Vector
[0083] The reaction mixture contained 100 ng of cDNA, 0.5 μl of 10× ligase buffer, 0.5 μl of 10 mM rATP (pH 7.5), 1 μl of UNI-ZAP XR vector (predigested, 1 μg/μl) and 0.5 μl of T4 DNA ligase (4 U/μl). The autoclaved DW was added in a total volume of 5 μl. The reaction was carried out at 12° C. for overnight.
Example 10
Packaging of Ligation Mixture Using Gigapack III Gold Packaging Extract
[0084] To the packaging extract, 2 μl of ligated DNA was added. After mixing it gently, the reaction mixture was incubated at 22° C. for 2 h. After the completion of incubation, 500 μl of SM buffer and 20 μl of chloroform were added. The contents were gently mixed and centrifuged at 7000 rpm at RT for 2 m. The supernatant was titrated for a suitable library dilution to be used for immunochemical screening.
Example 11
Plating and Titering-Blue and White Selection
[0085] Single colony of XL-1 Blue MRF′ cells was inoculated in LB containing 10 mM MgSO 4 (described in Appendix A) and 0.2% (w/v) maltose. Cells were grown at 37° C. at 220 rpm for overnight. The cells were pelleted at 4° C. at 4000 rpm for 10 m. Different library dilutions (1:10 and 1:100 v/v) were made in SM buffer. From each dilution 1 μl was taken and incubated with 200 μl of XL-1 Blue cells diluted in 10 mM MgSO 4 to 0.5 O.D 600 . The mix was incubated at 37° C. for 15 m in a tube. After incubation, 2-3 ml of NZY top agar (melted and cooled to approx. 48° C., Appendix A) mixed with 5 μl of 0.5 M IPTG and X-gal were plated onto the NZY agar plates. The plates were then incubated at 37° C. for 6-8 h.
Example 12
Amplification of cDNA Library
[0086] XL1 Blue cells were prepared as described earlier. Primary cDNA library (250 μl containing 5×10 4 phage particles) was incubated with 600 μl XL-1 blue cells (O.D 600 0.5) at 37° C. for 15 m. After incubation, mixture of 6.5 ml NZY top agar and infected material was plated onto 150 mm NZY agar plates. The plates were incubated at 37° C. for 6-8 h. The plates were then overlaid with 10 ml SM buffer and stirred gently at 4° C. for overnight. The suspension was pooled in a sterile polypropylene tube. The plates were rinsed with an additional 2 ml of SM buffer and pooled. Chloroform 5% v/v was added, mixed well and incubated for 15 m at RT. The sample was centrifuged at 1000 rpm for 10 m at 40° C. and supernatant was transferred in a fresh tube. The sample was again centrifuged and supernatant was transferred in a fresh polypropylene tube. To this, chloroform was added to a final concentration of 0.3% v/v and stored at 4° C. The titer of the amplified library was checked as described earlier.
Example 13
Immunochemical Screening of cDNA Library
[0087] The cDNA library of C. lunata in UNI-ZAP lambda vector was screened with pre-absorbed pooled CL sensitive patient's sera. The cDNA library was plated after appropriate dilution in SM buffer for obtaining 200-300 plaques per 90 mm NZY agar plates. The cDNA library (1 μl of 1:10 5 diluted in SM) was mixed with the host E. coli XL1-Blue MRF′ cells diluted in 10 mM MgSO 4 to OD 600 =0.5 in a sterile polystyrene falcon tube. The cells were incubated at 37° C. for 15 m to allow the phage to attach to the cells. To this, 3 ml of NZY top agar (melted and cooled to 48° C.) was added and plated immediately onto NZY agar plates. The inverted plates were incubated at 42° C. (4-6 h) until the plaques just begin to form. Soaked the numbered nitrocellulose filter with 10 mM IPTG. The dried nitrocellulose filters were placed on the agar surface in contact with the plaques, taking care to avoid air bubbles under the filter. Using a syringe needle, pierced the filter and agar at asymmetric positions to facilitate paper alignment following staining. The layered plates were incubated at 37° C. for 4 h to induce expression. The filters were removed, washed twice with TBS (2 m each) and incubated in blocking buffer for 1 h at RT. After washing twice with TBS at RT (5 m each), it was incubated with serum 1:10 v/v at 37° C. for overnight. The filters were then washed and incubated in conjugate solution 1:1000 v/v in TBS at 37° C. for 3 h. The filters were washed with TBST thrice (10 m each) and color was developed. The reaction was stopped by rinsing the membranes with distilled water twice.
Example 14
Single-Clone Excision Protocol
[0088] The plaque showing IgE binding was cored out from the agar plate and transferred to a sterile microcentrifuge tube containing 500 μl of SM buffer and 20 μl of chloroform. Vortexed the microcentrifuge tube to release the phage particles into the SM buffer followed by incubation at 4° C. overnight (phage stock). Separate cultures of XL1 and SOLR in LB broth supplemented with 0.2% (w/v) maltose and 10 mM MgSO 4 were obtained as described earlier. On the following day, XL1 Blue and SOLR cells were spun down at 6000 rpm for 5 m at 4° C. and resuspended in 10 mM MgSO 4 at an OD 600 of 1.0. The following components were mixed in a 15 ml sterile polypropylene tube-200 μl of XL1-Blue MRF′ cells at an OD 600 of 1.0; 5 μl of phage stock and 1 μl of the ExAssist helper phage (>1×10 6 pfu/μl). Incubated the tube at 37° C. for 15 in, added 3 ml of LB broth and incubated for 3 h at 37° C. with shaking at 220 rpm. Heated the falcon at 65° C. for 20 m and centrifuged at 10,000 rpm at 4° C. for 10 m. Decanted the phage supernatant into sterile microcentrifuge tube. To plate excised phagemids, 200 μl of SOLR cells were mixed with 2 μl of phage supernatant followed by incubation at 37° C. for 15 m. Plated 200 μl of the cell mixture on LB-ampicillin agar plates (50 μg/ml) and incubated overnight at 37° C.
Example 15
PCR Amplification
[0089] In general, a 50 μl of PCR reaction mixture contained,
[0000]
10x PCR buffer
5.0
μl
dNTP's
4.0
μl (0.2 mM each)
Forward Primer
150
ng
Reverse Primer
150
ng
Template
10-50
ng
Enzyme
0.5
μl (3 U/μl)
DW
To make up the volume to 50
μl
Amplification Conditions:
[0000]
Initial denaturation, 94° C./5 m and added the enzyme
Denaturation, 94° C./1 m
Annealing, 55° C./2 m
Extension, 72° C./2 m
Final extension, 72° C./7′ for 25 cycles.
The size of the amplified insert was determined by agarose gel electrophoresis.
Example 16
Automated DNA Sequencing
[0096] Automated DNA Sequencing was performed using fluorescent dye-terminator chemistry with thermal cycle sequencing. The sequencing reaction was set up as described below: Setting up of the sequencing reaction:
[0000]
Components
Volume
Dye terminator Ready Reaction mix
8 μl
Template DNA
Varied
Primer (4 pm)
Varied
DW
Varied
20 μl
The thermal cycling profile (25 cycles) was as
[0000]
Denaturation
96°
C./10 sec
Annealing
50°
C./5 sec
Polymerization
60°
C./4 m
Sequencing of DNA samples was performed on ABI-377, DNA Sequencer
Example 17
Expression and Immunological Characterization of the cDNA Encoding 12 kDa Protein
[0099] The cDNA insert subcloned into pBluescript SK (+/−) phagemid commercial kit was expressed under lacZ promoter. The phagemid was inoculated into 250 ml LB broth with 100 μg/ml of ampicillin and incubated at 37° C. with shaking (200 rpm) until the absorbance (OD 600 ) reached 0.2. Added IPTG at a final concentration of 1.0 mmol/L and the cultures were further grown for 5 hours at 37° C. with shaking (200 rpm). The cells were spun down at 6000 rpm for 15 min at 4° C. and suspended in 3 ml of 50 mM Tris-HCl, pH 7.5. The cells were sonicated and centrifuged at 6000 rpm for 45 min at 4° C. The supernatant was separated and was analyzed on 10% SDS-PAGE gel under reducing and denaturing conditions. After transferring the proteins onto NCM, the IgE/IgG binding activity of the fusion protein was evaluated. The patient's serum 1:10 v/v and anti CL rabbit serum 1:2000 v/v were used.
Expression of Recombinant Form of 12 kDa Protein in E. coli
Example 18
PCR Reaction to Clone cDNA Encoding 12 kDa Protein
[0100] The standard PCR is typically done in 50-100 □l reaction volume and in addition to sample DNA may also contain 50 mMKCl, 10 mMTrisCl, (pH8.4), 1.5 mMMgCl 2 , 250 nmoles, primers, 200 □mdNTPmix, 2.5 units of Taq DNA Polymerase.
[0101] The reaction mix used generally contained:
Template DNA=20 ng Primers=200 moles dNTPs=0.2 μM 10×PCR buffer=1× Taq DNA pol.=1.5 U The reaction mix in 50 μl volume: Template=10 μl Primers=2 μl dNTPs=4 μl 10×PCR buffer=5 μl PCR grade water=29.5 μl Taq.pol=0.5 μl The reaction conditions maintained were: Step I—95° C.=5 min. (initial denaturation) Step II—94° C.=60 sec. (denaturation of template DNA) Step III—55° C.=60 sec. (primer annealing to the template) Step IV—72° C.=90 sec. (extension by Taq pol) Step V—72° C.=5-7 min. (final extension) Step VI—4° C.=15 min. The reaction (Step II-IV) was cycled 25 times. The PCR conditions decided depend upon the particular primers used, GC content of the template DNA.
Example 19
Restriction Digestion
[0000]
Restriction enzyme buffer (10×)=(1×) final conc.
DNA=1 μg
Restriction enzyme used=1 U to completely digest 1 μg of DNA.
[0126] For complete digestion of DNA the 50 μl reaction mix contained DNA appropriately diluted and 5 μl of assay buffer. The volume was made up by good quality autoclaved water. Finally the enzyme was added. Incubation was done at 37° C., for 3 hrs.
[0127] After first enzyme treatment, heat inactivation was done to stop its non-specific activity. The reaction mix was heated at 65° C. for 15 min. Precipitation was done by adding 0.6 volumes of ammonium acetate and 2.5 volumes of 100% ethanol. Incubate at −20° C., overnight, centrifuged and washed the pellet with 75% ethanol. The pellet was air-dried and then reaction was put up with second enzyme in similar way.
Example 20
Ligation
[0128] The most important thing considered during cloning is the reannealing of the cut ends, which leads to plasmid recircularization. This was prevented by phosphatase treatment that removes 5′ phosphate group to suppress self-ligation. Ligase catalyzes formation of phosphodiester bonds between two nucleotides one with 3′ hydroxyl and other with 5′ phosphate. This way only the foreign DNA insert can be ligated with the vector and self-ligation is minimized. The ligation mix (11 □l) contained:
[0129] 5 μl of 2.2× reaction buffer and various ratios of vector and insert. 0.5 μl of T4 DNA ligase was finally added. The reaction mix was incubated at 16° C., overnight.
Example 21
Preparation of Competent Cells
[0130] Inoculated single colony of E. coli strain to be made competent, e.g. DH5α cells into a 5 ml LB tube and grown overnight at 37° C. The next day secondary culture was done (diluted 1 ml in 100 ml of culture). Grown at 37° C. 250 rpm, 2 hrs approximately for the cells to reach OD of 0.3. OD more than 0.4 leads to decrease in competence i.e. decreases the efficiency of transformation. The culture was aliquoted into prechilled polypropylene sterile tubes and left on ice. The cells need to be kept on ice subsequently. Cells were pelleted down at 3000 rpm, 4° C. for 7 min. (higher speed affects the viability of cells). The cell pellet was suspended gently in 5-6 ml of ice-cold CaCl 2 solution (see in reagents). Cells were pelleted down at 2500 rpm, 4° C., and 5 min.
[0131] Cells were resuspended in ice cold CaCl 2 and incubated on ice for 30-40 min. Cells were pelleted down at same speed. Cell pellet was resuspended in ice cold CaCl 2 . This re-suspension is final and needs to be done very well. The suspension should be kept on ice for about 1 hr. Finally the cells are aliquoted as 100 μl and stored at −70° C.
[0132] Any aliquot taken out should not be refrozen. Competence of cells is assessed by transformation with a known plasmid vector and seeing the number of colonies that appear.
[0133] No. of transformant colonies per aliquot (μl)×105=No, of transformants per μg of DNA used for transformation.
Example 22
Transformation
[0134] For 100 μl of competent cells 10-20 ng of DNA usually suffices (in the volume of 10-20 μl). Competent cells with DNA were swirled gently and kept on ice for 15-20 min. This mix was then incubated at 42° C. for 2 min and immediately put on ice and kept for 5 min. This treatment is called “heat shock treatment” which actually causes DNA to enter inside the cells. The cells were revived with 300 μl of LB media and kept at 37° C., 260 rpm, 1-2 hrs. The cells were plated on LB amp plates and plates kept for overnight incubation at 37° C. Remaining part of transformation mixture can be stored at 4° C.
Example 23
Plasmid Isolation Alkaline Lysis (Mini Prep)
[0135] To confirm the expressed clone, plasmid isolation was carried out by alkaline lysis method. Inoculated single bacterial colony in 5 ml LB medium overnight containing appropriate antibiotic, e.g. here ampicillin (50 μg/ml). The cells were pelleted down at 6000 rpm, 15 min 4° C. The cells were thoroughly mixed with 150 μl of TEG buffer by vortexing. Then cells were kept on ice for five-min. Added 300 μl of alkaline SDS was added. The solution becomes clear and slimy. Added ice-cold 200 μl potassium acetate and incubated on ice for half an hour. This step precipitates all genomic DNA and cell debris. Then centrifuged at 12000 rpm for 30 min, 4° C. Then the clear supernatant was taken out and 0.6 volumes of isopropanol was added and kept on ice for 10-15 min. Then centrifuged for 25 min at 12000 rpm, 4° C. The glassy pellet is difficult to see, thus care needs to be taken while rejecting the supernatant. The pellet was given a wash with 70% ethanol and then with 100% ethanol. The pellet was air dried and dissolved in water and analyzed on 1% agarose gel. The plasmids isolated were then checked with PCR and restriction digestion to confirm the insert of desired size.
Example 24
Expression and Purification of 12-kDa Recombinant Protein
[0136] The positive clone encoding 12 kDa protein was transformed into BL21 E. coli cells. The single clone was inoculated in 5 ml LB broth containing 100 μg/ml of ampicillin and incubated overnight at 37° C. with shaking (200 rpm). This culture was sub-cultured into 250 ml LB broth with 100 μg/ml of ampicillin and incubated at 37° C. with shaking (200 rpm) until the absorbance (OD 600 ) reached 0.2. Added IPTG at a final concentration of 1.0 mmol/L and the cultures were further grown for 5 hours at 37° C. with shaking (200 rpm). The cells were spun down at 6000 rpm for 15 min at 4° C. and suspended in 3 ml of 50 mM Tris-HCl, pH 7.5. The cells were sonicated and centrifuged at 6000 rpm for 45 min at 4° C. The sonicated lysate was loaded onto equilibrated Ni-NTA slurry and incubated for an hour for binding in equilibration buffer containing 10 mMTrsi.Cl, 100 mMsodium phosphate buffer and 500 mM NaCl pH 8.5. The non-specific bound proteins were washed off using wash buffer containing 10 mMTrsi.Cl, 100 mMsodium phosphate buffer and 500 mM NaCl pH 6.2. The bound protein was eluted using wash buffer containing gradient of imidazole and finally eluted at 200 mM imidazole. The protein content was estimated by known method [9] and separated 12% SDS-PAGE gel under reducing and denaturing conditions. FIG. 1 shows the expression and purification of 12 kDa protein on SDS PAGE.
Example 25
SDS PAGE Analysis
[0137] SDSPAGE was performed by known methods [10]
[0000]
RESOLVING
STACKING
CONTENTS.
GEL(15%)
GEL(5%)
Acrylamide
3.75
ml
600
μl
Distilled water
5.1
ml
2.7
ml
Tris ClpH8.8
2.25
ml
—
TrispH6.8
—
375
μl
10% SDS
112.5
□l
37.5
μl
Temed
5.7
□l
3.75
μl
10% APS
37.5
□l
13.5
μl
[0138] The samples were prepared as follows:
[0000] 30 μl eluted sample+1× sample dye (loading buffer)
Boil the samples for 10 min at 100° C. in the dry bath. Load the samples on to the gel along with the molecular weight marker. Run the electrophoresis in 1 liter electrode buffer 1× containing 14.4 gms Glycine, 3.03 gms Tris Cl., and 1% SDS at 120V, 80 mA. The gel is stained with CBB or silver stain to visualize the protein of very little yield.
Example 26
Absorption Spectra of Purified Recombinant Protein
[0139] The absorption spectrum of 12 kDa protein was done to find the characteristic absorption maxima peaks of heme containing proteins and shows the peaks at 410 nm, 510 nm and 550 nm. 1 mg/ml protein was taken in a clean quartz cuvette and absorption scan carried out in the range of 210 nm-700 nm on Shimadzu UV 2100 S. the absorption maxima was recorded and the plot was scaled appropriately to fit all the peaks. FIG. 2 shows the absorption spectra of 12 kDa protein.
Example 27
Circular Dichroism of 12 kDa Protein
[0140] CD spectra were carried out with 1 mg/ml of each recombinant and native protein in 20 mM phosphate buffer in the far-UV range. Thermal scans in the range of 10-100° C. were also carried out to find the melting temperature (Tm) of recombinant 12 kDa protein. FIG. 3 shows the CD spectra of 12 kDa protein.
Example 28
Immunoblot
[0141] The protein is transferred after SDSPAGE onto nitrocellulose membrane by electrotransfer by known methods [11]. Briefly, when the run is over, the gel is transferred on to the nitrocellulose membrane sheet, in the cassette, such that the gel is on negative side and the transfer takes place from negative to positive side. The electro transfer is carried out for about 3 hrs in the transfer buffer containing 6.9 gms Glycine, 6.6 gms Tris and 250 ml methanol the volume was made up to 1 liter with distilled water) at 80 mA. After transfer is over Ponceau staining of NCP is done to see if the transfer is appropriate. Destaining of the NCP is done using PBST solution and wash with PBS. Keep the blot (NCP) in 3% BSA solution/defatted milk (made in water or PBS) used as blocking solution at 4° C., overnight or at 37° C. at 40 rpm for 1 hour. The excess blocking reagent is washed off with PBST. The blot is then incubated with primary antibody (peroxidase conjugated monoclonal antibody could be used too). The incubation could be at 4° C. for overnight or at 37° C. for 3 hours. The excess antibody is washed off with PBST. The secondary antibody is added which has to be peroxidase conjugated and kept for 1-2 hrs at 37° C. The blot is washed by PBST and kept for developing by the addition of substrate, i.e. 15 mg diaminobenzene and 15 μl H 2 O 2 are added freshly to acetate buffer (0.34 g in 50 ml water+39 μl acetic acid). The blot shows brown bands upon developing if the antigen looked for is present. The allergen can also be checked similarly if the primary antibody used is serum of patient allergic to that source. FIG. 4 shows the immunoblot of 12 kDa protein using 15 patients sera.
Example 29
ELISA
[0142] Each well of the microtitre plate was coated with 1 μg of protein in 100 μl of coating buffer pH 9.6. The plate was incubated overnight at 4° C. After washing with 0.1 M PBS containing 0.1% Tween 20 (PBST), the free sites were blocked with 200 μl 3% bovine serum albumin or non fat dry milk for 1 h at RT. The plates were washed again and incubated with either 100 μl serum at 4° C. overnight. IgE binding was determined by allergic patients sera (1:10 v/v) and IgG binding by polyclonal mice sera/commercial antibodies (1:2000 v/v). The plate was washed again and incubated for 4 h at RT with 100 μl antihuman-IgE peroxidase (1:1000 v/v) or anti mice IgG peroxidase (1:2000 v/v). The plate was washed and color was developed using substrate containing 8 mg o-phenylene diaminebenzidine and 18 μl H 2 O 2 in citrate buffer at 37° C. The reaction was stopped with 50 μl 5 N H 2 SO 4 after 40 m and read at 490 nm in ELISA reader (Dynatech). FIG. 5 shows the ELISA table of 12 kDa protein. For ELISA inhibition, the sera used is preincubated mix of patient's serum with different concentrations of purified recombinant or native 12 kDa protein. Rest the methodology remains the same as ELISA. FIG. 6 shows the ELISA inhibition graph. It is seen from the graph that for 50% inhibition of binding of IgE antibodies against Curvularia when incubated with native or recombinant 12 kDa protein, 7-5 ng of these proteins were sufficient. This shows that both the native and recombinant forms of 12 kDa protein are comparable immunologically and allergenically potent.
[0143] FIG. 7 further demonstrates the presence of the disclosed 12 kDa allergen in different grass extracts in immunoblot. The experiment was carried out by probing recombinant 12 kDa protein on immunoblot with different grass sensitive sera. The experiment was confirmed by probing different extracts with polyclonal antibodies raised in mice against recombinant 12 kDa protein.
[0144] Table 1 shows the specific IgE values against recombinant 12 kDa protein in different fungal positive sera. This data demonstrates the presence of detectable specific antibodies against recombinant 12 kDa protein in different fungal sensitized patient's sera.
[0145] Table 2 shows the specific IgE antibodies against the recombinant 12 kDa protein in different grass positive sera. These patients were negative to different fungi but positive to recombinant 12 kDa protein. This shows that this 12 kDa protein contributes significantly to the grass pollen allergy also. This protein can thus be useful for detection of grass and fungal allergies without using large number of grass or fungal extracts.
REFERENCES
[0000]
1. Shen H D, Lin W L, Tsai J J, Liaw S F, Han S H. Allergenic components in three different species of Penicillium : crossreactivity among major allergens. Clin. Exp. Allergy 1996; 26: 444-451.
2. Elliot M W, Taylor A J. Allergic bronchopulmonary aspergillosis. Clin. Exp. Allergy 1997; 27: 55-59
3. Valenta R, Vrtala S, Laffer S, Spitzauer S, Kraft D. Recombinant allergens. Allergy 1998; 53: 552-561
4. Chapman M D, Smith A M, Vailes L D, Arruda L K, Dhanraj V, Pomes A. Recombinant allergens for diagnosis and therapy of allergic disease. J Allergy Clin Immunol 2000; 106:409-18
5. Gupta R., Singh B P, Sridhara S., Gaur S N., Kumar R., Chaudhary V K, Arora N. Allergenic cross-reactivities of Curvularia lunata with other airborne fungal species. Allergy 2002; 57: 636-640 Pauli G. Evolution in the understanding of cross-reactivities of respiratory allergens: the role of recombinant allergens. Int Arch Allergy Immunol 2000; 123:183-195
7. Grendelmeier P S, Holzmann D, Himlyn M, Weichel M, Tresch S, Ruckert B, Menz G, Ferreira F, Blaser K, Wüthrich B, Crameri R. Native Art v 1 and recombinant Art v 1 are able to induce humoral and T cell-mediated in vitro and in vivo responses in mugwort allergy. J Allergy Clin Immunol 2003; 111:1328-36
8. Expression of tropomyosin from Blattella germanica as a recombinant non-fusion protein in Pichia pastoris and comparison of its IgE reactivity with its native counterpart. Jeong K Y, Lee J, Lee I Y, Hong C S Ree H, Yonga T S Protein Exp Purification 2004; 37: 273-278
9. Lowry O H, Rosebrough N J, Farr A L, Randall R J. Protein measurement with the Folin phenol reagent. J. Biol. Chem. 1951; 193:265-275.
10. Laemmli U K. Cleavage of structural proteins during the assembly of the head of bacteriophage T 4 . Nature 1970; 227: 680-685
11. Towbin H, Staehelin T, Gordon J. Electrophoresis transfer of proteins from polyacrylamide gels to nitrocellulose sheets: Procedure and some applications. Proc. Natl. Acad. Sci. USA 1976; 76: 4350-4354
12. Voller A, Bidwell D, Barlette A. Microplate enzyme immunoassay for the immunodiagnosis of virus infection. In: Rose N, Feldman H (eds): Manual of Clinical Immunology. USA. American Society of Microbiology. 1976: p 506.
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The present invention discloses the detection of an important 12K-Da protein having cross-reactivity amongst different prevalent allergenic grasses and fungi can be useful for detection of respiratory allergies. Conventionally, the whole extracts that are used for diagnosis are unable to specifically detect the causative agents. In addition, they are also responsible for additional non-specific sensitivities in patients to other components present in the extract. If a single cross-reactive protein is available, it can replace large number of extracts used for detection of raised IgE levels in allergy by ELISA, immunoblotting and the likes. Further, number of pricks would be reduced and this would benefit both patient and clinicians. It is further realized that production of such a protein by recombinant methods can lead to its availability in pure form and bulk amounts required for routine diagnosis.
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BACKGROUND OF THE INVENTION
The present invention relates generally to devices for controllably dispensing liquids, and more specifically to drip-type odorizing and disinfectant liquid dispensers having a pivotal actuator and an electronic detector and signal system.
Deodorizing and disinfecting treatment systems for urinals and toilet bowls are known in the art and are typically wall mounted units having wick-type dispensing systems that periodically allow drops of olfactory and biocidal fluid to flow through a tube and onto the surface to be treated, such as onto the inside of the toilet bowl or the inside wall of a urinal. The wicks are generally mounted to absorb fluid from a gravity-fed liquid reservoir, while another end of the wick is positioned to drip into a flow tube or other liquid guiding mechanism. At least a portion of the wick is exposed to facilitate odorizing of the surrounding area within a room. Hence, the wick serves as the liquid transfer mechanism between the reservoir, the flow tube and the odorizing medium.
Several problems exist with conventional wick-type systems since they typically require a number of time consuming and messy steps for installation and servicing. Generally, for installation or servicing, a wick must be inserted in a support tube and subsequently splayed at both of its ends so that the wick properly absorbs the liquid. Furthermore, the wick must typically be adjusted so that a sufficient length reaches either the liquid reservoir or the conveying tube to enable the drops to properly flow at a predetermined adjustable rate. The rate is generally adjusted by the size and type of wick used.
There are numerous types of olfactory and disinfectant liquids which typically have differing viscosities. A wick-type system will normally require a different wick for different viscosities of liquid given that the absorption and flow rates will differ depending upon the viscosity of the liquid. This generally requires the service personnel or user to stock a plurality of different wicks. If a user decides to use the same wick, the user is often restricted to using liquids having the same viscosity. Also, the wicks transfer (absorb) the liquid molecules with the lowest specific gravity first, such as alcohol or fragrance molecules. Therefore, the fragrance decreases rapidly after only several drops. Another problem occurs with conventional wick-type systems because the reservoir and wicks are typically exposed to the air. This allows dirt and air-borne particles to accumulate in the reservoir and on the wick. Consequently, clogging occurs because the wick transfers dirt particles to the flow tube opening. Clogging also occurs due to surfactants.
Other types of deodorizing and disinfecting systems are known which operate based on the flush action of the urinal or toilet and are often in-line devices. One such device is disclosed in U.S. Pat. No. 4,984,306 and is a system for injecting metered amounts of chemicals into flush water as the flush water enters the toilet. A small bore in an injector assembly connects to a chemical reservoir so that the chemical is directed into the flush water as the flush water passes through the assembly. Such in-line devices are typically costly and require time consuming installation. Other systems include devices having multiple discharge tubes to service more than one urinal or toilet. However, these units are costly and complex and require time consuming installation procedures.
Known deodorizing and disinfecting systems typically include a container of liquid chemical that must be periodically replenished at predetermined intervals. Replacement of the container is often time consuming and residue producing, as it may require disconnection of supply tubes and the container and subsequent reattachment of the container within the unit. Such systems do not provide a quick and easy method for replacing the chemical liquid container at periodic intervals.
Accordingly, it is a object of the present invention to substantially overcome the above-described problems.
It is another object of the present invention to provide a novel actuator nozzle to facilitate easy and rapid removal and installation of a chemical-containing vessel in a deodorizing and disinfecting system.
It is a further object of the present invention to provide a chemical dispensing apparatus that is simple and inexpensive to manufacture.
SUMMARY OF THE INVENTION
The disadvantages of known chemical delivery apparatus are substantially overcome with the present invention by providing a novel pivotal actuator system for a chemical delivery apparatus.
The present invention provides a novel pivotal actuator nozzle that may be rotated outwardly to facilitate quick and easy replacement of the chemical-containing container. When the container requires replacement, it is simply rotated a few degrees outwardly with the nozzle outwardly rotating along with rotation of the container. The container is then removed while the nozzle remains in the outwardly rotated position to facilitate rapid attachment of the replacement container. Once the replacement container has been connected to the nozzle, the container is downwardly rotated a few degrees as the nozzle pivots therewith until the bottle is in its original position.
More specifically, the present invention includes an actuator system for a chemical dispensing apparatus where the chemical dispensing apparatus includes a chemical-containing vessel and a housing. The invention includes an actuator nozzle having a receiving aperture and a dispensing aperture, where the receiving aperture is operatively coupled to the vessel to receive the chemicals contained within the vessel. The dispensing aperture is coupled to the receiving aperture and is also connected to a conveying tube to direct the chemical from the vessel, through the conveying tube and into a chemical receiving receptacle. Also included is a means for ejecting the chemical from the vessel into the actuator nozzle. The vessel in the preferred embodiment is a canister or bottle equipped with a pump to dispense fluid from the vessel. The present invention can also be used with aerosol dispensing vessels, as well as with equivalent fluid containing devices.
The actuator nozzle is slidingly and pivotally mounted in the housing, and is configured to slide vertically relative to the housing and to pivot outwardly to permit reciprocal engagement and disengagement of an actuating mechanism of the vessel while maintaining communication with the fluid conveying tube. The actuator nozzle remains in an upward and outwardly pivoted position when the vessel is disengaged from the actuator nozzle to facilitate reengagement of a replacement vessel with the actuator nozzle.
BRIEF DESCRIPTION OF THE DRAWINGS
The features of the present invention which are believed to be novel are set forth with particularity in the appended claims. The invention, together with further objects and advantages thereof, may best be understood by reference to the following description in conjunction with the accompanying drawings.
FIG. 1 is a front elevational sectional view of a specific embodiment of a chemical delivery apparatus having a pivotal actuator nozzle according to the prevent invention;
FIG. 2 is a side elevational sectional view of the chemical delivery apparatus having a pivotal actuator nozzle shown in FIG. 1;
FIG. 3 is a perspective internal structural view of a specific embodiment of the apparatus shown in FIG. 1 in accordance with the invention having the front cover shown in outline form.
FIG. 4A is a top plan view of a specific embodiment of a pivotal actuator nozzle and a portion of the chemical delivery apparatus which guides movement of the nozzle;
FIG. 4B is a side elevational sectional view of the pivotal actuator nozzle shown in FIG. 4A;
FIGS. 4C-4E are side elevational views of the pivotal actuator nozzle shown in FIG. 3A, particularly showing oblong shaped tabs;
FIG. 4F is a front elevational view of the pivotal actuator shown in FIG. 3A;
FIG. 5 is a block diagram of an integrated circuit for use as part of a control circuit according to the present invention;
FIG. 6 is a circuit diagram of a specific embodiment of the control circuitry for a chemical delivery apparatus having a pivotal actuator nozzle;
FIG. 7 is a side elevational view of a hose insert according to the present invention shown disposed within the conveying tube;
FIGS. 8a and 9a are side elevational views of the hose insert shown in FIG. 7; and
FIGS. 8b-8c and 9b-9c are end views of the hose insert shown in FIGS. 8a and 9a, respectively.
DETAILED DESCRIPTION OF THE INVENTION
Although the below description will be made with reference to liquids for odorizing and disinfecting urinals, toilets and the like, it will be understood that the inventive dispensing apparatus may be used for controllably dispensing any suitable chemical, such as chlorine or other liquids for pools or other applications.
Referring now to FIGS. 1-3, a chemical delivery apparatus having a pivotal actuator is shown generally as 10. The apparatus includes a housing 12 and a hinged cover 14 (FIGS. 2-3). The housing 12 includes a viewing window 18 for visually observing the status of various aspects of the apparatus 10, as will be described hereinafter. The housing 12 and the cover 14 may be formed from high-impact plastic, metal or other suitable material, as is well known in the art.
A nozzle assembly 20 includes a pivotal actuator nozzle 22 which is mounted between a pair of oppositely disposed runners or guides 30 attached to a motor plate 31, as will be described hereinafter. A chemical-containing canister or bottle 34 is disposed in housing 12 and includes a hollow pump stem 36 attached to a pump mechanism 37 which directs an olfactory and/or disinfecting liquid 38 from a bottom portion 40 within the bottle to a receiving aperture 42 (FIG. 3) disposed within the nozzle 22. The nozzle 22 is disposed at the other end of the hollow pump stem 36. The receiving aperture 42 is operatively coupled to the bottle 34 through the pump stem 36 so that liquid 38 from the bottle is directed into the nozzle 22. The bottle 34 has a ferrule 48 disposed above a collar 50. The housing 12 includes a pair of integrally formed mounting grooves 52 and 54 which secure the collar 50 in place, thus securing the bottle 34 within the housing 12.
The bottle 34 includes a plurality of specifically oriented indentations 70 molded into the bottle which serve as a keying mechanism. The housing 12 has corresponding keys in the form of protrusions 72 which mate with the indentations 70 in the bottle 34 so that only properly keyed bottles may be inserted and correctly positioned into the housing.
The housing 12 includes a base portion 80 upon which the bottle 34 rests and a back wall 82 integrally formed with the base portion. The cover 14 includes side walls 84 forming a skirt such that when the cover engages the housing 12, a fully enclosed structure is formed which encloses the bottle 34 and other internal support and operating mechanisms. The cover 14 is hinged to the housing 12 along the base portion 80 so that the cover may be conveniently rotated away from the housing to allow removal and replacement of the bottle 34. A plurality of mode switches 86 or a switch array 15 is housed under the cover 14, the function of which will be described in greater detail hereinafter. The cover 14 may also be keyed to the housing 12 to prevent tampering and unauthorized access to the internal portion of the housing.
A conveying tube 90 is attached to a dispensing aperture 92 of the actuator nozzle 22. The dispensing aperture 92 operatively communicates with the receiving aperture 42 such that liquid 38 drawn from the bottle 34 into the receiving aperture is directed within the nozzle 22 to the dispensing aperture 92. The conveying tube 90 transports liquid 38 drawn from the bottle 34 by the pumping action of the actuator nozzle 22 into the conveying tube 90 and into an in-line connector 94.
The in-line connector 94 is secured to the back wall 82 of the housing 12 by a threaded retaining ring or clamp 96. The in-line connector 94 includes a nipple portion 98 to which the conveying tube 90 is coupled. The in-line connector 94 also includes a rotatable portion 100 which is capable of swiveling one-hundred and eighty degrees relative to the body of the in-line connector. This allows an in-line tube 110 to be attached to the in-line connector 94 for convenient and easy placement and routing of the in-line tube so that the liquid 38 within the bottle 34, when dispensed, is directed into a urinal, toilet or other suitable destination (not shown). A nut 112 or other pressure fitting may be used to secure the in-line tube 100 to the end of the in-line connector 94. Any suitable in-line connector 94 capable of fluid transport may be used. The conveying tube 90 includes a hose insert or restrictor insert 114 (FIGS. 1 and 2) which provides a number of advantages, as will be described in greater detail hereinafter.
Referring now to FIGS. 3 and 4A-4F, the nozzle assembly 20 is shown generally in FIGS. 3 and 4A. The nozzle 22 is slidingly and pivotally mounted within the pair of guides 30 attached to the motor plate 31. This allows the nozzle 22 to slide or to be reciprocally displaced in a vertical direction relative to the housing, as shown by arrow 115 of FIGS. 2-3. The nozzle 22 is also capable of outward pivotal movement relative to the housing 12 to permit reciprocal engagement and disengagement of the bottle 34, as shown by arrow 116 of FIGS. 3 and 4E. As the nozzle 22 pivots, it maintains communication with the conveying tube 90 to prevent leakage of liquid 38. All connections between the bottle 34, the nozzle 22, the conveying tube 90 and the in-line connector 94 are liquid-tight to prevent inadvertent fluid spills or leaks.
The guides 30 each are formed as "L-shaped" brackets that project outwardly and away from the motor plate 31 to which they are mounted (FIG. 3). The guides 30 may be constructed from plastic, metal or any other suitable material. Each guide 30 includes a guide base 118 and a guide mount portion 120 outwardly projecting from the guide base at right angles. The guide base 118 is secured to the motor plate 31 by screws, rivets, bolts, welds or any other suitable method. Two guide mount portions 120 opposingly face each other so that the nozzle 22 may be mounted therebetween. Each guide mount portion 120 comprises a vertical groove or channel 122 disposed along its center, as best shown in FIG. 4A. The channel 122 may extend along the entire height of the guide mount portion 120, as shown in the illustrated embodiment, or may extend for only a portion of the height of the guide mount, thus providing a bounded channel. Each channel 122 has two vertical sidewalls 124 and a vertical base portion 126 to facilitate vertical displacement and guiding of the nozzle 22.
The nozzle 22 includes two tabs 128 outwardly projecting from opposite sides of the nozzle, which tabs are configured to communicate with the corresponding channels 122 disposed in the guide mount portions 120. When the nozzle 22 is placed between the opposing guides 30, the tabs 128 on each side of the nozzle form a releasable interference fit with the channels 122 sufficient to retain the nozzle in place while allowing simple hand pressure to vertically displace the nozzle.
As best seen in FIGS. 4C and 4D, each of the tabs 128 are slightly oblong in cross-sectional shape and have a first diameter 130 parallel to the length of the channels 122. The first diameter 130 is greater in length than a second transverse diameter 132 which is perpendicular to the first diameter 130. When the nozzle 22 is in a position so that the first diameter 130 of the tab 128 is parallel to the length of the channels 122, the nozzle is vertically and reciprocally displaceable using hand pressure. This is due to the dimension of the second diameter 132 relative to the width of the channels 122. The nozzle 22 may be vertically displaced relative to the channels 122 when the nozzle is between a fully unrotated position (zero degrees, as illustrated in FIG. 4C) and an outwardly rotated position of less than about twenty degrees, as illustrated in FIG. 4E. The angle of rotation is a function of the width of channels 122, the dimension of tabs 128, and the material from which tabs are constructed. Thus, rotation of the nozzle 22 by less than about twenty degrees in the illustrated embodiment is not sufficient to cause the first diameter 130 of the tabs 128 to operatively engage the channel sidewalls 124 in a frictional manner.
When the nozzle 22 is rotated or pivoted forward, as shown by arrow 116 in FIG. 4E such as by rotating the bottle 34 outwardly from the housing 12, the bottle 34 which is attached to the nozzle may be rapidly and conveniently removed and replaced. Rotation of the nozzle 22 causes the first or longer diameter 130 of the tabs 128 to frictionally engage the sidewalls 124 of the channels 122 causing the nozzle 22 to be vertically locked in position relative to the channels. Thus, rotation of the nozzle 22 by about twenty degrees is sufficient to frictionally maintain the nozzle in the outwardly rotated position to facilitate engagement and disengagement of the bottle 34 from the nozzle at an angle relative to the housing 12. Preferably, rotation of the nozzle between about twenty and thirty degrees in the illustrated embodiment facilitates frictional locking engagement. The tabs 128 are formed from material, such as plastic, which may slightly deform under pressure. Thus, the tabs 128 slightly deform within the channel sidewalls 124 creating friction sufficient to maintain the nozzle 22 in the outwardly rotated position. This facilitates rapid and convenient reciprocal engagement and disengagement of the bottle 34 from the nozzle 22. The bottle 34 is preferably held by the nozzle by means of a pressure fit, as is well known in the art. Alternately, the tabs 128 may be formed from hard material while the channel 122 and guide portions 120 are formed from softer, slightly deformable material to achieve the same result.
As best shown in FIG. 3, the switch array 86, such as a dual in-line package switch, is mounted to a printed circuit board 150 which is secured to ribs (not shown) molded into the housing 12. The switch array 86 allows the user to selectively modify the operation of the apparatus 10, as will be described in greater detail hereinafter. A visual indication of the status of the apparatus 10 is provided by two light-emitting diodes (LED1 151 and LED2 152) which are visible through the viewing window 18. Alternatively, LCD displays, or any other suitable visual display device may be used.
The apparatus 10 includes a speed reduction transmission system 172 mounted to the motor plate 31. The transmission system 172 includes a main pinion gear 174 driven by a drive motor 176 operationally coupled to the main pinion gear. The pinion gear 174 couples to a drive gear 178 having a secondary pinion gear 180 which in turn couples to an intermediate gear 182. The intermediate gear 182 has an actuator drive gear 184 which engages an actuating member 186, such as a segment gear or the like. The actuating member 186 has a cam or hammer 188 for contacting the top of the nozzle 22 to depress the nozzle. A spring 190 disposed under the nozzle 22 or within the bottle 34 causes the actuator nozzle 22 to rise after being depressed to facilitate the pumping action. However, it will be recognized that any suitable pump actuating mechanism may be employed to pump fluid from the bottle 34 and into nozzle 22.
The housing 12 includes a pair of integrally formed holding cavities 192 and 194 for housing a pair of 1.5 volt D-cell batteries 196 (FIG. 3) which supply power to various portions of the apparatus 10.
Referring now to FIGS. 3, 5, and 6, FIG. 5 is a block diagram generally depicting an integrated circuit (IC) 300 and FIG. 6 is a schematic diagram implementing the integrated circuit shown in FIG. 5. The integrated circuit 300 is used as part of a control circuit 302 for operating the dispensing apparatus 10. The IC 300 is preferably a model TC-2020 chip manufactured by Holtek Microelectronics Inc., Taiwan. However, any suitably programmed microcomputer or other discrete circuitry may also be used.
The IC 300 includes an oscillator circuit 304 for providing oscillator output signals OSC2 306, OSC3 308 and OSC4 310, and for receiving a variable oscillator input signal OSC1 312. The oscillator circuit 304 provides a frequency output signal 324 to a divider "A" circuit 328 which divides the frequency output signal by a value of 1024 to produce a divider "A" first output signal 330. The number of pulses or the frequency of the output signal 324 varies in accordance with resistance and capacitance changes that are selectable by the user through a selectable switching arrangement in conjunction with the signals OSC1 312, OSC2 306, OSC3 308 and OSC4 310, as will be described hereinafter.
An input control circuit 340 receives various inputs, such as TEST 350, CDS 352, OFF 354, RESET 356, CONT1 360, CONT2 362 DAY/NIGHT 364 and BATT 368. The input control circuit 340 generates an input control first output signal 380 which controls a divider "B" circuit 384. The divider "B" circuit 384 receives its frequency input from the divider "A" first output signal 330 and divides that frequency by a value of 1024. The divider "B" circuit 384 then produces a divider "B" output signal 386 under control of the input control circuit 340. The divider "B" circuit 384 can either divide the input by a value of 512 or by a value of 1024, depending upon the state of the CONT2 pin 362. Preferably, the CONT2 pin is set high so that the divider "B" circuit divides by a value of 1024.
The input control circuit 340 also provides an input control second output signal 390 which is received by an output control circuit 392. Additionally, the input control circuit 340 generates an input control third output signal 394 which is received by a counter & latch circuit 396.
The output control circuit 392 provides an output pulse signal OP 410 to activate a drive motor 412 to periodically depress the nozzle 22. For example, during normal operation, a pulse interval of a predetermined number of counts that correspond to approximately 15 minutes is set so that an output pulse OP 410 occurs every 15 minutes to eject liquid 38 from the bottle 34.
The output control circuit 392 also includes a multi-tone audible signal generating circuit 414 that generates an output buzzer pulse BZB 416 to activate an external buzzer circuit 418. The output control circuit 392 receives a DUTY signal 420 determined by a resistor/capacitor combination R8 and C6, shown in FIG. 6. If the DUTY signal 420 is connected to ground, then the OP signal 410 provides a 1/3 duty cycle pulse stream having a pulse width of about one second. The R/C combination is chosen so that the drive motor 412 is activated for a period of time sufficient to depress the nozzle 22. The output control circuit 392 also receives a counter & latch signal 422 from the counter & latch circuit 396 that indicates when a predetermined time-out period has occurred, such as when a total of 3,072 pulses have been output (e.g. the bottle 34 is empty) so that the drive motor 412 may be inhibited and the user notified to replace the bottle.
The divider "A" 328 divides the frequency output signal 324 from the oscillator circuit 304 into a visual flash pulse signal to drive a first LED drive circuit 440 and a second LED drive circuit 442. The first and second LED drive circuits 440 and 442 activate and deactivate a first LED 446 and a second LED 448, respectively. A maximum pulse count signal 450 is latched by the counter & latch circuit 396 at a maximum counter value corresponding to when a refill of the bottle 34 is required, such as when the count equals 3072. This corresponds to a bottle empty condition. The maximum pulse count signal 450 is coupled to the second LED driver circuit 442 and directs the second LED driver circuit 442 to activate the second LED 448 to provide a visual indication corresponding to the bottle empty condition.
The first LED driver circuit 440 drives the first LED 446 when a low battery condition is detected. Both the first LED driver circuit 440 and the second LED driver circuit 442 include a one-shot circuit (not shown) which provides a 1/128 duty cycle to the corresponding LED's 446 and 448 so that power is conserved.
The oscillator circuit 304 includes a bilateral switch block 480 which contains a switch "A" 482 and a switch "B" 484. Switch "A" and switch "B" 482, 484 are controlled by a switch control signal 486 generated by the counter & latch circuit 346 that allows the oscillator circuit 304 to operate in one of two predetermined modes. When the oscillator circuit 304 is operating in an "A" mode, an oscillator "A" 488 is operational. The oscillator "A" 488 includes the input signal OSC1 312 and the output signals OSC2 306 and OSC3 308, while an oscillator "B" 490 includes the input signal OSC1 and the output signals OSC2 306 and OSC4 310. When the counter & latch circuit 396 is incremented to its maximum pulse count of 3072, the switch control signal 486 is issued to instruct the bilateral switch block 480 to switch to an oscillator "B" mode. The generation of particular frequencies for the oscillator circuit 304 will be described in greater detail hereinafter with respect to the circuit diagram of FIG. 6.
Referring to FIGS. 3, 5, and 6, the IC 300 with support circuitry necessary to complete the control circuit 302 for operation of the dispensing apparatus 10 is shown in FIG. 6. The control circuit 302 includes a memory backup circuit 500 formed by a diode D1 and a capacitor C1 to provide a suitable voltage level to the IC 300 when power is removed. A power supply circuit 502 includes an "ON/OFF" switch S1 coupled to a current limiting resistor R1. The current limiting resistor R1 couples to a filtering capacitor C2 and a diode D2. A three volt DC source of power, such as the batteries 196, supply three volts to the diode D2 and is labeled Power Line A.
A reset circuit 504 formed by a "RESET" momentary switch S2 and a capacitor C3 allows the IC 300 to be manually reset upon the depression of the RESET switch S2. For example, when the bottle 34 is empty, a new bottle is inserted into the apparatus 10 and the user then resets the control circuitry 302 to again begin the timing and control process.
A light sensing circuit 508 includes a photo-sensitive element, such as a photo resistor R2, which has a resistance that varies with the amount of light sensed by the resistor R2. An "AUTO/24 HR" switch S3 allows selection between continuous operation (24 hour continuous operation) and automatic operation (operation dependent on lighting conditions). When the AUTO/24 HR switch S3 is closed, the power line A connects to the CDS pin 352 in the IC 300 through a diode D3 thereby bypassing the photo resistor R2. This indicates to the input control circuit 340 that a continuous twenty-four hour operation has been selected. The diode D3 is coupled to a diode D4 and a current limiting resistor R4 that, in turn, is coupled to ground. The resistors R3 and R4 serve as current limiting resistors. When operating in the automatic mode (switch S3 is open), a variable voltage level on the CDS pin 352 indicates the amount of light detected, and the output pin OP 410 is controlled in response thereto.
A "DAY/NIGHT" switch S4 allows the user to select between a day and a night mode of operation. The DAY/NIGHT switch S4 in combination with the AUTO/24 HR switch S3 provides a selectable daytime mode or nighttime mode. To select the daytime mode, the AUTO/24 HR switch S3 is opened, indicating the automatic mode. Once in automatic mode, the apparatus 10 is responsive to the amount of light detected, as indicated by the voltage level present on the CDS pin 352.
An internal counter 510 in the input control circuit 340, such as a divide by fifteen counter, calculates a preset time period during which, if an insufficient amount of light is sensed, a night condition is indicated. When the DAY/NIGHT switch S4 and the AUTO/24 HR switch S3 are both open, a high voltage level is produced on the DAY pin 364 and if the CDS pin 352 is set to a low voltage (insufficient amount of light), the internal counter 510 starts to count. If there is insufficient light for a night threshold period of approximately 15 times the pulse interval of fifteen minutes, the input control circuit 340 assumes that a night condition exists. When the level of light has increased sufficiently, the CDS pin 352 becomes high due to voltage level produced by the photo resistor R2. This indicates that morning has arrived (e.g., enough light for a sufficient period of time).
When this occurs, the output control circuit 392 issues four pulses on the signal OP 410 to command the drive motor 412 to eject four pulses of liquid from the bottle 34. This feature is designed to increase the fragrance level in the morning after no liquid was dispensed during the night. If the darkness period is less than a night threshold period, the input control circuit 340 assumes that light is sensed periodically, as may occur when the ambient light is turned off for a short period of time. If this occurs, the counter 510 within the input control circuit 340 is reset each time the CDS pin 352 indicates that sufficient light has been sensed.
The control circuit 302 may also output pulses on the OP signal 410 when the control circuit determines that nighttime has arrived. When the DAY/NIGHT switch S4 is closed and the AUTO/24 HR switch S3 is opened, the IC 300 generates four pulses on the OP signal 410 at the beginning of the time when an insufficient amount of light has been sensed for a predetermined period of time. This indicates that nighttime has arrived.
During the 24 hour mode, the AUTO/24 HR switch S3 is closed and the control circuit 302 generates an output pulse OP 410 approximately every fifteen minutes during both morning and night conditions, regardless of lighting conditions. No sequence of four pulses OP 410 is generated during the morning and night transition periods.
A variable frequency selection circuit 520 allows the user to select between a normal mode or a selectable mode where a light and heavy liquid dispensing operation may be selected. The variable frequency selection circuit 520 includes a NORMAL switch S5 and a LIGHT/HEAVY switch S6. When the NORMAL switch S5 is opened, a normal mode is selected and the LIGHT/HEAVY switch S6 has no effect on system operation. When the NORMAL switch S5 is closed, the LIGHT/HEAVY switch S6 controls selection of the mode of the oscillator circuit 304.
In the normal mode (NORMAL switch S5 in the opened position) the amount of capacitance present at the OSC2 pin 306 is essentially governed by a capacitor C4 coupled between the OSC2 pin 306 and the combination of resistors R5 and R6 coupled to the OSC4 pin 310 and the OSC1 pin 312, respectively. The closing of the LIGHT/HEAVY switch S6 has minimal effect and only slightly changes the capacitance present at the OSC2 pin 306. For example, in the normal mode with the NORMAL switch S5 open, the closing of the LIGHT/HEAVY switch S6 may only charge the basic oscillating frequency of the oscillator circuit 304 by less than 0.7% of its nominal frequency of 1.2 KHz.
When the NORMAL switch S5 is closed, however, a capacitor CS is essentially in parallel with the capacitor C4, thus significantly modifying the capacitance between the OSC4 pin 310 and the OSC2 pin 306. When the NORMAL switch S5 and the LIGHT/HEAVY switch S6 are both closed, a resistor R7 is in parallel with a resistor R8, where the parallel resistor combination is coupled between the OSC3 pin 308 and the capacitor combination of C4 and CS. This modified R/C combination causes the oscillator circuit 304 to operate at an increased frequency, essentially double that of the normal frequency, or 2.4 KHz.
This increased frequency causes the counters and dividers 340, 328 and 384 to operate at an increased frequency and causes the maximum count value to be reached sooner than in the normal mode of operation. Such a condition represents a heavy mode of operation where activation of the nozzle 22 occurs at twice the rate as in the normal mode of operation.
When the NORMAL switch S5 is closed and the LIGHT/HEAVY switch S6 is opened, the resistor R7 is essentially an open circuit and only the resistor R8 is in combination with the capacitors C4 and C5. This modified R/C combination causes the oscillator circuit 304 to operate at one-half of its normal frequency, or 0.6 KHz. This reduced frequency represents a light mode of operation since the nozzle 22 will be operated at one-half of its normal rate and dispense one-half of the normal amount of liquid. This allows the bottle of liquid 38 to last twice as long compared to the normal mode of operation.
The duty cycle pin DUTY 420 is connected to the combination of a capacitor C6 and a resistor R9. The other end of the capacitor C6 is connected to ground while the other end of the resistor R9 is connected to the power line A. The combination of the resistor R9 and the capacitor C6 forms an R/C timing circuit which controls the duty cycle of the integrated circuit.
A test switch S7 coupled to a TEST pin 350 may be depressed to temporarily ground the TEST pin and place the integrated circuit 300 in a test mode. When the TEST pin 350 is connected to ground, the divider "B" circuit 384 and the counter latch circuit 396 are tested for proper functioning.
The CONT2 pin 352 is tied high so that a maximum count of output pulses OP 410 (ejections from the nozzle 22) must equal 3072 before the input control circuit 340 determines that the bottle 34 is empty. High and low voltage levels may be applied to CONT2 pin 352 can vary the maximum count, thus varying the output of pulses on OP 410.
In operation, specifically in the normal mode of operation, the oscillator circuit 304 produces a 1.2 KHz frequency on the frequency output signal 324. The divider "A" circuit then divides the frequency output signal 324 by a value of 1024 to produce approximately a 1.2 Hz. signal (1.1719 Hz, divider "A" first output signal 330). The divider "A" first output signal 330 is also routed to an input 522 of the first LED driver circuit 440 and an input 523 of the second LED driver circuit.
The divider "B" circuit 384 divides the frequency output signal 324 by a value of 1024 and produces approximately a 0.001144 Hz signal on the divider "B" output signal 386. This represents a pulse which occurs approximately every 873.8 seconds or approximately every 15 minutes (14.56 minutes). The counter latch circuit 396 counts 3072 such pulses occurring approximately every 15 minutes to produce the maximum pulse count signal 450. This occurs approximately once every 31 days and indicates that the bottle is empty.
A battery voltage detection circuit 524 determines when the battery voltage drops below a predetermined threshold set by a voltage divider that includes resistors R15, R16 and a variable resistor R17. The variable resistor R17 may be adjusted to vary the low battery threshold level. The variable voltage level set by the variable resistor R17 drives the base of an NPN transistor Q1. The emitter of the transistor Q1 is grounded while the collector is coupled to the power line A through the current limiting resistor R17. The collector of the transistor Q1 also drives the base of a transistor Q2. The emitter of the transistor Q2 is coupled to ground while its collector provides the threshold indicator to the BATT pin 308 of the IC 300.
When the battery voltage is above the minimum threshold, for example, above 2.7 volts, the transistor Q1 is turned on and the transistor Q2 is turned off, indicating to the IC 300 that the battery has remaining useful life. Accordingly, the first LED 151 is not illuminated.
The collector of the transistor Q2 is internally pulled to a high voltage level within the IC 300. When the battery voltage falls below the minimum threshold value, the transistor Q1 turns off which allows the collector of the transistor Q1 to be pulled high through the resistor R17. This turns on transistor Q2 causing its collector to be coupled to ground, thus providing a low signal to the BATT pin 368. The IC 300 interprets this as a low battery condition and illuminates the first LED 151.
The first LED 151 is coupled between the LED1 pin 446 and a current limiting resistor R18. The first LED 151 indicates the state of the battery and depends upon the condition of the BATT pin 368. The IC 300 energizes the first LED 151 at a predetermined duty cycle when a low battery condition is detected. The first LED 151 will flash at a periodic rate driven by the first LED drive circuit 440. The flashing rate or duty cycle of the first LED 151 is 1/128. This is selected to conserve power while informing the user of a low battery condition.
However, the visual indicating mode of the first and second LEDs 151 and 152 may be reversed by simple reconfiguration of the CONT1 pin 360. If the CONT1 pin 360 is tied low instead of high, the first LED 151 will not flash when a low power condition is sensed but rather, will flash only when the battery voltage level is sufficient. Alternatively, an AC/DC adapter (not shown) may be incorporated into the apparatus 10 so that the dispensing device may be plugged into an AC wall socket, as is well known in the art.
The second LED 152 is activated when the number of OP pulses 410 reaches the predetermined maximum pulse count to indicate that the bottle 34 is empty and must be changed. The CONT 2 pin 362 controls the second LED 152 to indicate a bottle empty condition. The counter & latch circuit 396 supplies the a maximum pulse count signal 450 to energize the second LED 152. The second LED 152 is similarly coupled between the LED2 pin 448 and the Power Line A through a current limiting resistor R18a.
The second LED 152 is energized only after the counter & latch circuit 396 has counted to its maximum count of 3072. This notifies the user to replace the bottle 34. Approximately 745.6 hours are required for the maximum pulse count of 3072 to be reached while operating in the 24 hour mode. Therefore, the bottle 34 need only be changed approximately every 31 days. In the light mode (non-heavy mode) of operation, the time interval between bottle changes may be double, or 62 days. This time period may increase by use of the DAY/NIGHT mode, which only dispenses liquid during certain preselected day or night conditions.
A motor driver circuit 526 includes transistors Q3 and Q4, resistors R19, R20 and current limiting resistor R21. The motor driver circuit 526 provides drive current for the motor 412 which activates the cam 188 to depress the nozzle 22. When the IC 300 provides the OP pin 410 with a pulse, the transistor Q3 turns on, thus driving the base of the transistor Q4 low. This turns on the transistor Q4 to place the drive motor 412 across the power line A and ground thereby activating the motor. Conversely, a low level on the OP pin 410 allows the base of the transistor Q4 to float high, thus turning off the transistor Q4 and isolating the drive motor 412.
The oscillating buzzer circuit 418 generates an audible tone when the output pin BZB 416 is driven high. This occurs when the counter & latch circuit 396 counts to the maximum pulse count of 3072 OP pulses, thereby audibly indicating that the bottle 34 is empty. The BZB pin 416 is coupled to the base of a transistor Q5 through a current limiting resistor R22. When the BZB pin 416 is activated, the transistor Q5 oscillates and amplifies the signal to produce an audible tone through an audio speaker SP1. The audio speaker SP1 and an inductor L1 are connected in parallel between the collector of the transistor Q5 and the power line A. If the CONT1 pin 350 is connected to ground, the audio feature is disabled.
A "TONE/QUIET" switch S8, when closed, connects the base of the transistor Q5 to ground thereby turning-off the transistor Q5 to prevent the audible tone from occurring. Hence, the switch S8 allows the user to select between a quiet mode and an audible tone mode.
The first and second LEDs 151 and 152 and the optical detector R2 communicate with the ambient environment through the view window 18 located in the upper portion of the housing 12, as shown in FIG. 1. Each of the switches S3, S4, S5, S6 and S7 may be a single switch included in a multiple switch dual in-line package (DIP). The switches S1 and S8 may be, for example, toggle switches while the switch S2 may be, for example, a momentary contact switch.
In operation, the control circuit 302, set for a specific depression frequency, activates the drive motor 412 which causes the cam/hammer 188 to depress the nozzle 22. The olfactory liquid 38 is ejected by the subsequent pump action into the conveying tube 90 through the nozzle 22. Preferably, the amount of depression force and the rate at which the nozzle 22 is depressed is adjusted so that a sufficient quantity of the liquid 38 is dispensed.
The control circuit 302 receives power through the ON/OFF switch S1 which connects the 3-volt battery supply (Power Line A) to the control circuit. The apparatus 10 is controlled so that the nozzle 22 will be periodically depressed to dispense approximately 28 ounces of liquid 38 in a 31-day period. The pump (e.g., nozzle 22 and stem 36) may be a 110 milliliter pump or any suitable pump. A predetermined count is selected which corresponds to the number of depressions necessary to dispense the entire amount of liquid during that 31-day period. Once the predetermined count is reached, for example 3072 depressions of the nozzle 22, the second LED 152 is activated.
The LIGHT/HEAVY switch S6 allows the user to vary the depression frequency according to desired fragrance levels. For example, when the NORMAL switch S5 is closed so that the LIGHT/HEAVY switch S6 is effective, the depression frequency may be varied from one depression every 30 minutes in the light operation mode, to one depression every 71/2 minutes in the heavy operation mode, depending on the desired odorizing level. Depression of the nozzle 22 occurs about once every 15 minutes in the normal operation mode, where the LIGHT/HEAVY switch S6 has no effect.
When the AUTO/24 HR. switch S3 is set in the auto operation mode, the optical detector R2 will turn off the dispensing apparatus 10 if there is insufficient illumination in the room to activate the optical detector. This allows the conservation of olfactory liquid 38 and battery power during periods in which the urinal or toilet bowl are not being used.
Referring now to FIGS. 2 and 7, FIG. 7 shows the hose insert or restrictor insert 114 in greater detail where the hose insert is shown secured within the conveying tube 90. The conveying tube 90 has an outside diameter 600 and an inside diameter 602 which may change slightly along its length since the material from which the conveying tube is formed is elastic or deformable in nature. Thus, the conveying tube 90 may deform under the pressure of the liquid 38 ejected into the conveying tube. The conveying tube 90 may, for example, be formed from soft plastic or rubber such as silicone rubber or surgical-type rubber tubing. However, any suitable elastic or rubber material may be used.
The restrictor insert 114 is configured to selectively regulate the volume of liquid 38 ejected into the conveying tube 90 and hence, the liquid back pressure. The conveying tube 90 is defined as having a source end 610 for receiving the liquid 38 from the nozzle 22 and the pump mechanism 37, and a drain end 612 for discharging the liquid into the nipple 98. The ability to regulate the volume of liquid 38 ejected by the nozzle 22 and the ability to regulate and maintain a predetermined level of liquid back pressure is extremely advantageous. Several conditions exist which necessitate use of the restrictor insert 114.
First, as liquid 38 is ejected into the conveying tube 90 and travels downwardly within the tube, a siphon effect is created which tends to create a slight vacuum within the conveying tube. This causes additional liquid 38 to be "sucked" from the bottle 34 through the nozzle 22. This may result in premature emptying of the bottle 34.
Second, the conveying tube 90 eventually terminates at its suitable destination device (not shown) which may, for example, be a urinal, a toilet and the like. Such devices, when activated or flushed, tend to create a vacuum further increasing the vacuum which may already be present within the conveying tube 90. The siphon effect described above is further increased when the destination device is flushed which may also result in premature emptying of the bottle. This effect may be amplified during simultaneous liquid ejection and destination device flushing since the vacuum or siphon effect acts upon an "open" nozzle 22.
Third, when the nozzle 22 is functioning properly, the siphon effect does not present problems. However, the nozzle 22 may not be functioning properly and may become temporarily unseated after liquid 38 has been ejected. Dirt and particulate matter may cause the nozzle 22 to temporarily jam, thus allowing liquid 38 to be drawn out of the bottle 34 between ejections. If the nozzle 22 becomes temporarily jammed (in an open or "leaky" state), the siphon effect can drain a significant portion of the liquid 38 from the bottle 34. The restrictor insert 114 reduces or eliminates the additional volume of liquid discharged due to the above-described act.
Fourth, the nozzle 22 and the pump mechanism 37 perform optimally when a predetermined amount of back pressure is created within the conveying tube 90 during liquid ejection. Such back pressure, in part, is due the elastic nature of the conveying tube 90. The amount of back pressure required depends upon the size of the nozzle orifice (not shown). For reasons of manufacturability, different nozzles 22 may be interchanged, which may have different diameter orifices. To insure optimal nozzle 22 performance, the back pressure must be adjusted for each different nozzle type. The restrictor insert 114 provides a method for adjusting and maintaining the required amount of back pressure within the conveying tube 90.
Referring now to FIGS. 7, 8a-8c and 9a-9c, the restrictor insert 114 shown generally. The restrictor insert 114 includes a head portion 620, a tail portion 622 and a central portion 624 connected between the head portion and the tail portion. The head portion 620, the tail portion 622 and the central portion 624 are preferably integrally formed using injection molding or other suitable heat processing techniques.
The restrictor insert 114 is disposed within the conveying tube 90 between the source end 610 and the drain end 612 of the conveying tube to selectively regulate the volume of liquid 38 ejected into the conveying tube. The restrictor insert 114 is coaxially disposed within the conveying tube 90 such that the head portion 620 is disposed toward the source end 610 and the tail portion 622 is disposed toward the drain end 612 of the conveying tube.
The head portion 620 has an outside diameter 630 slightly greater than the inside diameter 602 of the conveying tube 90 to form an interference fit with the conveying tube. Since the conveying tube 90 is formed from relatively elastic material, the conveying tube essentially "stretches" or deforms around the head portion 620. Such deformation, in part, tends to retain the restrictor insert 114 vertically in place.
However, the degree of deformation of the conveying tube 90 is not so great as to create a liquid-tight seal between the head portion 620 and the conveying tube 90. The fluid 38 ejected into the conveying tube 90 creates a sufficient amount of pressure to temporarily deform the conveying tube which is in proximity with the head portion 620, thus allowing the liquid to pass along the surface of the head portion 620 and down through the conveying tube. Such resistance to the passage of the fluid 38 around the head portion 620 essentially prevents inadvertent discharge of fluid 38 due to the siphon effect of fluid flowing within the conveying tube 90 below the vertical level of the restrictor insert 114. Additionally, should the nozzle 22 become temporarily "mis-seated" during liquid ejection, such resistance to fluid flow prevents undesirable discharge of liquid into the conveying tube 90.
The head portion 620 also provides a "self-cleaning" feature. Particulate matter and dirt may accumulate or may be dispensed into the conveying tube 90 during liquid ejection, which could clog typical devices. However, such particulate matter tends to become trapped between the outside surface of the head portion 620 and the conveying tube 90 where the elastic nature of the conveying tube traps the particles in place. The liquid 38 is able to flow around any trapped particulate matter.
The above-described pressure created within the conveying tube 90 between the nozzle 22 and the restrictor insert 114 is referred to as "back pressure" and is required for optimal nozzle 22 performance. The amount of back pressure is adjustable through selective vertical placement of the restrictor insert 114 within the conveying tube 90. The amount of back pressure is inversely proportional to the total amount of deformation of the conveying tube 90 and is dependent upon the diameter and the length of the conveying tube subject to deformation.
If the restrictor insert 114 is placed relatively far from the nozzle 22, a large portion of the length of the conveying tube 90 is subject to deformation and hence, the amount of back pressure is small. If the restrictor insert 114 is placed relatively close to the nozzle 22, a small portion of the length of the conveying tube 90 is subject to deformation and hence, the amount of back pressure is great. By selecting the appropriate vertical position within the conveying tube 90 to fixedly place the restrictor insert 114, the back pressure to which the nozzle 22 is subject can be selectively regulated and maintained.
The ability to selectively regulate the amount of back pressure by appropriate vertical placement of the restrictor insert 114 may, for example, modify the volume of liquid pumped over time by about between 5% to 20%. Thus, in a selected period of time, the amount of liquid ejected can be modified by up to 20%. Similarly, increasing the diameter of the conveying tube 90 and the restrictor insert 114 decreases the amount of back pressure while reducing the diameter of the conveying tube and the restrictor insert increases the amount of back pressure. Additionally, the amount of back pressure may be adjusted by changing the degree of elasticity of the conveying tube 90 by appropriate selection of material. Increasing the elasticity of the conveying tube 90 decreases the back pressure while decreasing the elasticity increases the back pressure.
The central portion 624 has a diameter 634 smaller than the diameter 630 of the head portion 620 and permits the fluid 38 to flow along the central portion without resistance. The head portion 620 is integrally formed with the central portion 624 from a suitable plastic material. The tail portion 622 is also integrally formed with the central portion 624 and may, for example, have a diameter 636 greater than the diameter 634 of the central portion. However, this does not present resistance to fluid flow, as will be described hereinafter.
The tail portion 622 includes an annular flange 638 disposed about its circumference forming a barb which creates an interference fit with the conveying tube 90. This fixedly secures the restrictor insert 114 at a selected vertical position within the conveying tube 90. The annular flange 638 or barb has an increased diameter over the diameter 636 of the tail portion 622 such that the conveying tube 90 essentially "stretches" or deforms around the tail portion and the barb 638.
However, to allow the unimpeded flow of liquid from the head portion 620, along the central portion 624 and through the tail portion 622, a longitudinal channel 644 is disposed along a portion of the tail portion and may also be disposed along a portion of the central portion. The channel 644 also passes through the annular flange 638 so that the flange does not inhibit fluid flow.
The channel 644 may extend to a distal end 648 of the tail portion 622 so that the distal end does not terminate in a flat cross-sectional area, as illustrated in FIGS. 8c and 9c. Accordingly, if the restrictor insert 114 is fixedly placed within the conveying tube 90 far from the nozzle 22 and abutting the nipple 98, the distal end 648 cannot block liquid flow into the nipple since the channel permits unimpeded liquid flow.
A specific embodiment of a chemical delivery apparatus having a pivotal actuator according to the present invention has been described for the purpose of illustrating the manner in which the invention may be made and used. It should be understood that implementation of other variations and modifications of the invention and its various aspects will be apparent to those skilled in the art, and that the invention is not limited by the specific embodiments described. It is therefore contemplated to cover by the present invention any and all modifications, variations, or equivalents that fall within the true spirit and scope of the basic underlying principles disclosed and claimed herein.
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The invention includes an actuator system for a chemical dispensing apparatus where the chemical dispensing apparatus includes a chemical-containing vessel and a housing. The invention also includes an actuator nozzle having a receiving aperture and a dispensing aperture where the receiving aperture is operatively coupled to the vessel to receive the chemicals contained within the vessel. The dispensing aperture is coupled to the receiving aperture and is also connected to a conveying tube to direct the chemical from the vessel, through the tube and into a chemical receiving receptacle. Also included is a structure for ejecting the chemical from the vessel into the actuator nozzle. The actuator nozzle is slidingly and pivotally mounted in the housing and is configured to slide vertically relative to the housing and is also configured to pivot outwardly relative to the housing to permit reciprocal engagement and disengagement of the vessel while maintaining communication with the conveying tube. The actuator nozzle remains in an upward and outwardly pivoted position when the vessel is disengaged from the actuator nozzle to facilitate reengagement of the vessel with the actuator nozzle.
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CROSS REFERENCE TO RELATED APPLICATIONS
[0001] The present Application claims the benefit of priority to the following International Application: PCT Patent Application No. PCT/FR2004/002284 titled “System for the Multiple Control of Electric Motors” filed on Sep. 9, 2004 (which is incorporated by reference in its entirety).
BACKGROUND
[0002] The present application relates to the area of the multiple control of electric motors fitted to motor vehicles, particularly those used in the function known as central door locking whereby the locking and unlocking of the doors is controlled centrally. However, many other motors can also be considered, such as those of the seats, the mirrors, the flaps of the air-conditioning system, the fuel flap, the sunroof, the windows, etc.
[0003] The expression “system for the multiple control of motors” is used here to refer to a system designed to combine the commands of several electric motors in different combinations corresponding to different states of the function in question, such as partial or total locking/unlocking corresponding to the “lock”, “superlock” and “rear superlock” (child protection) states of the door locking function referred to above.
[0004] These motors are controlled by relays which in turn are operated by a microprocessor providing central coordination of the commands given by the user.
[0005] A recent technological advance particularly in so-called passive entry technology now allows the use of motors with significantly faster response times, typically a few milliseconds or tens of milliseconds, whereas response times used to be more than one hundred milliseconds, if not hundreds of milliseconds.
[0006] When considering the passive entry function, which allows the door to be opened when its handle is operated because of a badge worn by the user, the slightest wait is no longer acceptable.
[0007] Since these motors have speed of response characteristics close to those of the relays which control them, there is a problem with their multiple-control use in that their commands have to be synchronized more accurately if the system is to avoid transitional combinations which could create a functional state not desired by the user. In other words, and more practically, there is a risk that a car door may be unlocked without the user being aware of the fact.
[0008] The likelihood of these unwanted transitional combinations occurring is increased by the fact that the boxes of relays, sensors and motors provided for the function in question may come from different manufacturers, and may have disparate characteristics.
[0009] Answers to this problem have already been proposed, such as those described in document EP 0 924 372. These consist in introducing delays to each of the commands applied to the motors but this is deliberately to undo what is a valuable advance from the point of view of the vehicle user.
[0010] The applicant has aimed to make the best possible use of the speed characteristics of the new motors, while avoiding constraints in the choice of the manufacturers of the electronic boxes and sensors, as this would be industrially costly.
SUMMARY
[0011] One embodiment of the invention relates to a system for the multiple control of electric motors for operating accessories in a motor vehicle for combining the commands of several electric motors, each combination corresponding to a predetermined function state, wherein the system includes electric power supply means, relays for controlling the said motors, controlled by cutting off their power supply, and means for controlling the said relays, the said system being characterized in that it comprises switch means for cutting off the power supply to the said motors and the control means are designed to open or close the said switch means only when a predetermined state is reached.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] A clearer understanding of the present application will be made possible by the following description of an exemplary embodiment of the system for the multiple control of electric motors according to the invention, with reference to the appended drawings in which:
[0013] FIG. 1 is a functional circuit diagram of the multiple-control system according to the invention; and
[0014] FIG. 2 is a timing diagram of an example of combined commands issued by the control means of the multiple-control system according to the invention.
DETAILED DESCRIPTION
[0015] Referring to FIG. 1 , the system 1 for the multiple control of electric motors performing a function comprises, in addition to motors M 1 to Mn and SL 1 to SLm which are to be operated in combination, a controlling microprocessor 5 which, on the basis of instructions 2 from a user, opens or closes the contacts C 1 , C 2 , C 3 , C 4 , Ci, . . . , and the corresponding relays R 1 , R 2 , R 3 , R 4 , Ri, . . . .
[0016] In the example shown in FIG. 1 , R 1 , C 1 , and R 2 , C 2 are all in one relay box 6 , and R 3 , C 3 , R 4 , C 4 , R 5 , C 5 in another relay box 7 . Only two boxes have been shown but there may of course be more than this number.
[0017] A motor is controlled by two contacts. For example motor M 1 is controlled by the two contacts of box 6 . However, any given motor Mj (j being from 1 to n) or a motor SLk (k being from 1 to m) can be controlled by two relays Ri and Ri+1 from boxes from different manufacturers, like the motors Mn or SL 1 , which are connected, in the figure, to two boxes 6 and 7 .
[0018] All the contacts Ci have two positions 81 and 82 , either of whose terminals can be connected to a terminal 83 of a motor Mj or SLk. Terminal 83 is connected in position 81 to a supply 3 which is common to the motors of the function, and in position 82 to the supply return for the same motors. Here, this return is the reference potential, in the present case the ground 4 of the system 1 .
[0019] The structure thus defined makes it possible to connect the two terminals of a motor either to supply it with a positive or negative current I, or not to supply it therewith, in which case both terminals are connected to the same polarity, the supply 3 or ground 4 .
[0020] The microprocessor 5 is designed to control in combination the relays Ri, and hence the motors Mj or SLk, in view of the function to be performed, taking this structure into account in such a way as to avoid any inconsistency, notably inconsistencies leading to short-circuits or to undesired states of the function, and corresponding to temporary command combinations resulting from the fact that, for example, the boxes are from different manufacturers and that the motors are faster.
[0021] For example, to close the driver's door of a vehicle, only motor M 1 will be operated, while the other motors Mn or SL will be excluded. To lock the rear doors, two motors M 3 and M 4 could be operated, or the “rear superlock” motor SL 2 could be operated alone; but it is also possible, in this state of the function, to also lock the front passenger door through the motor M 2 . General locking will operate four motors M 1 to M 4 , or the two motors SL 1 and SL 2 , etc.
[0022] Here, all terminals 82 of contacts Ci are connected to terminal 11 of a JFET or MOSFET “smart power” transistor 10 , also designated by the letters SM, which furthermore is connected to the ground 4 of the system 1 . The transistor SM is controlled by an output 13 of the microprocessor 5 and sends it an “operating temperature correct” signal, as ordinarily delivered by “smart power” transistors, via a link 14 . These transistors work in two states: an off state and an on state. The off state allows the motor supply to be put in the rest mode.
[0023] The current I passing through the transistor SM is read on its terminal 11 and amplified by an operational amplifier 15 whose output is connected to an analogue-digital converter 16 which provides in real time the digital value of the current I to the microprocessor 5 via a link 17 .
[0024] The microprocessor 5 can thus control a motor Mj or SLk of its choice and collect the value of the resulting current I to compare it with a reference Gj defining correct operation of the motor, chosen according to signal processing methods known to those skilled in the art.
[0025] Referring to FIG. 2 , when the user requests the function performed by the system 1 , with a particular instruction designed to place the function in a particular state Ep, the instruction is transmitted to the microprocessor 5 by the link 2 . To place the function in the state Ep, the microprocessor determines, by considering the desired state Ep and the preceding state Ep−1, what combination of motors Mj and/or SLk should be supplied with electric current I and from this works out which relays Ri to operate, as in the normal way.
[0026] For example, in FIG. 2 , where the motors to be supplied are motors M 1 and Mn, the relays to be operated are relays R 1 , R 2 , and R 3 . The microprocessor 5 operates them and the contacts Ci switch to positions 81 or 82 depending on which combination is required.
[0027] As the transistor SM is not operated, it is in an off state, no current I flows through the motors and no unwanted state can occur while the contacts Ci with the relays Ri are switching.
[0028] After a sufficient period of time T 1 allowing all the relays in question R 1 , R 2 , R 3 to switch, the microprocessor 5 operates the transistor SM via the link 13 , turning it on and causing current to flow. The motors M 1 and M 2 are now connected to the supply 3 on one side and to ground 4 on the other, which causes the current I to flow through them.
[0029] After a second period of time T 2 sufficient for the motors M 1 , M 2 to reach the end of their travel, the desired state Ep is reached and the microprocessor stops the operation of the transistor SM.
[0030] Depending on the particular state Ep that has been reached, it is possible that the next state Ep+1, desired by the user, is naturally known or predictable, or even merely the most likely state. The microprocessor can anticipate this state Ep+1 by pre-positioning the relays Ri after a sufficient period of time T 3 to allow the transistor SM to return to the off state. This possible anticipation saves time T 1 during the next instruction from the user. This would particularly apply to “passive entry” for the general unlocking of car doors. On leaving the car and locking the doors, the user places the elements presented above in the open position.
[0031] If one motor fails, by short-circuiting or any other cause which abnormally increases the electric current I flowing through the motor, the current flowing through the transistor SM increases abnormally and the “smart power” transistor detects an abnormal temperature rise. It reports this to the microprocessor 5 via the link 14 , and the microprocessor can output a message or warning or pre-warning signal to the user.
[0032] When this happens, during repair work, the repairer can isolate the faulty motor Mj by prompting the microprocessor 5 to operate all the motors of the faulty function in turn, detecting the shape of the signal on the terminal 11 of the transistor SM, this signal being amplified by the amplifier 15 , digitized by the converter 16 and transmitted by the link 17 , and comparing each signal from each motor with the reference Gj of correct operation of the tested motor.
[0033] During this operation, the internal resistance (known as DSR for “drain-source resistance”) of the transistor SM is used as the current I measuring resistance.
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The system relates to electric motors for operating accessories in a motor vehicle for combining the commands of several electric motors. Each combination comprises electric power supply means, relays for controlling the motors and means for controlling the relays. Switch means are provided for cutting off the power supply to the motors and the control means are designed to open or close the switch means only when a predetermined state is reached.
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FIELD OF THE INVENTION
[0001] The present invention relates to the techniques used in obtaining polymer compositions and, more particularly, it relates to a copolymer composition having elastomeric properties at wide temperature ranges.
BACKGROUND OF THE INVENTION
[0002] There is a vast amount of polymer composition applications wherein the elements or objects therefrom require having elastomeric properties, that is, to exhibit extensibility and flexibility properties allowing them to recover their shape after being considerably extended.
[0003] Due to the above, a great variety of materials having elastomeric properties have been developed over time, with styrene-butadiene copolymers being among the most renowned and widely used ones:
[0004] Although it is possible to find in the state of the art a great variety of elastomeric polymer compositions having various mechanical or physical properties such as hardness, tensile strength, or modulus of elasticity, among others, the compositions known so far lose their elastomeric properties with temperature, which limits the optimal performance thereof when they are to be used in high-temperature applications.
[0005] With the development of more effective polymerization catalyzers, such as the one depicted in the patent application MX 9801717, it has been possible to control the structure of polymers, allowing thus to obtain regularity in chains. Thus, in the case of styrene elastomers, syndiotactic polystyrene has been used in order to achieve beneficial results for the properties of the polymer compositions therefrom.
[0006] For instance, U.S. Pat. No. 5,260,394 depicts a syndiotactic polystyrene copolymer with inserts of olefin and/or dienic monomers exhibiting proper chemical and thermal resistance properties, in addition to allowing an appropriate processing and good compatibility with other compositions. The copolymers depicted therein aim to have materials with good processing by injection molding due to their low glass transition temperature.
[0007] Likewise, U.S. Pat. No. 5,352,727 depicts a syndiotactic polystyrene composition modified with rubber aiming to provide such composition with better processing properties when it is reprocessed after being used once, keeping its mechanical and heat decomposition resistance properties after being reprocessed.
[0008] Generally, other documents such as U.S. Pat. No. 6,046,275; U.S. Pat. No. 6,191,197; U.S. Pat. No. 5,352,727; U.S. Pat. No. 5,260,394; U.S. Pat. No. 5,543,462; and U.S. Pat. No. 5,777,028 use various mixtures of syndiotactic polystyrene with other polymers or copolymers allowing to modify the mechanical and processing properties of such a polymer compositions.
[0009] However, none of these documents introduce a composition having elastomeric properties at wide temperature ranges since, due to the nature of the compatibilizing agents normally used to obtain compositions in stereoregular polymers, such compositions cannot be used at low temperatures and therefore the use of this kind of materials continues to be limited to temperatures over −4° F.
[0010] According to the above, we have pretended to overcome the disadvantages of known elastomeric compositions by obtaining a polymer composition not also having elastomeric properties at wide temperature ranges, but which can be used at high temperatures and keeps its impact strength, chemical, mechanical, and wear resistance properties under high temperatures, in addition to keep its elastomeric properties at temperatures under −4° F.
OBJECTS OF THE INVENTION
[0011] Considering the limitations of the compositions depicted in the previous art, it is an object of the present invention to provide a polymer composition having elastomeric properties at wide temperature ranges, which is homogeneous and compatible, such composition resulting from stereoregular polymers and not requiring the use of additional compatibilizing agents.
[0012] It is another object of the present invention to provide a polymer composition having elastomeric properties at wide temperature ranges which keeps its chemical, mechanical, and wear resistance properties, as well as its processing and impact strength properties.
[0013] Yet another object of the present invention is to provide a polymer composition having elastomeric properties at wide temperature ranges which is compatible with other polymer materials when being mixed with them.
[0014] Yet another object of the present invention is to provide a polymer composition having elastomeric properties at wide temperature ranges which may be properly processed as a film, by thermoforming, injection, or extrusion.
BRIEF DESCRIPTION OF THE FIGURES
[0015] Novel aspects considered to be characteristic of the present invention will be established with detail in the appended claims. However, the operation, as well as other objects and advantages thereof, will be better understood in the light of the following detailed description of a specific embodiment thereof, considered according to the appended figure, wherein:
[0016] FIG. 1 is a graph of the modulus of elasticity (G′) of some embodiments of the polymer composition of the present invention which are illustrated in the example.
DETAILED DESCRIPTION OF THE INVENTION
[0017] It has been found that a combination of dienic vinyl aromatic polymers having an orderly structure may result in a polymer composition having elastomeric properties at a temperature range from −121° F. (188.15 K) to 572° F. (573.15 K).
[0018] More specifically, the polymer composition of the present invention allowing to achieve elastomeric behavior at wide temperature ranges comprises from 15 to 85% by weight of a copolymer having at least a block from 10 to 5000 structural sequences, which are mainly syndiotactic in nature, of monomer units resulting from at least one substituted or unsubstituted vinyl aromatic monomer, and at least one block formed from 10 to 4000 monomer units resulting from at least one dienic monomer having mainly a 1,4-cis structure; from 15 to 85% by weight of a polymer resulting from dienic monomers, having a molecular weight from 1000 to 600000, the contents of 1,4-cis-type monomer units being of at least 90%; and up to 70% of a polymer resulting from substituted or unsubstituted vinyl aromatic monomers, having a molecular weight from 1000 to 500000 and a degree of syndiotacticity in terms of syndiotactic pentads of at least 95%.
[0019] In a preferred embodiment of the present invention, vinyl aromatic monomers are selected from styrene and substituted styrene, the substituents being preferably selected from the alkyl, halide, alkoxyl, and amine groups. In a specific embodiment, vinyl aromatic monomers are selected from styrene, 4-methyl-styrene, 4-ter-butyl styrene, 4-methoxy styrene, 4-trimethylsililoxy styrene, 4-bromo styrene, and 4-(N—N′-dimethyl amine) styrene.
[0020] Regarding the dienic monomer, in the preferred embodiment of the present invention, the dienic monomer is selected from buta-1,3-diene and 2-methyl buta-1,3-diene.
[0021] In an additional embodiment of the polymer composition of the present invention, the fraction formed by the monomer units resulting from the dienic monomer may be partially or fully hydrogenated, that is, monomer units —CH 2 —CH═CH—CH 2 — may be partially or fully converted into the monomer units —CH 2 —CH 2 —CH 2 —CH 2 —, whereas the monomer units —CH 2 —C(CH═CH 2 )H— may be partially or fully converted into the monomer units —CH 2 —C(CH 2 —CH 3 )H—, 95% of the monomer units resulting from the dienic monomer being preferably hydrogenated.
[0022] In an additional embodiment of the present invention, the polymer composition contains from 0.01 to 4% by weight of at least one organic or inorganic additive depending on the final destination of the composition and, more preferably, less than 3.7%.
[0023] Preferably, inorganic additives are selected from compounds containing aluminum and, more preferably, aluminum oxide, or compounds with the general formula (—Al(X)O—)n, wherein X is a hydroxyl, alkoxyde, or alkyl group, which are obtained by making react the compounds having the general formula (—Al(R)O—)m with water or alcohols, wherein R is an alkyl group, n and m are natural numbers which may be residues from the catalytic system.
[0024] Likewise, it is preferred that organic additives include at least one antioxidant agent, preferably selected from useful antioxidants in compositions containing styrene and butadiene and, more preferably, selected from those containing phenols, phosphates, and amines.
[0025] The polymer composition of the present invention has a first glass transition temperature (T g 1) within the temperature range between −148° F. and −194° F.; a second glass transition temperature (T g 2) within the temperature range between 203° F. and 248° F.; as well as a melting temperature T m within the temperature range between 428° F. and 572° F. The elastomeric behavior of the polymer composition of the present invention ranges from −121° F. up to the dienic-polymer degradation temperature. Likewise, the modulus of elasticity may vary between 10 and 1000 MPa within the temperature range between −121° F. and 194° F., and between 3 and 100 MPa within the temperature range between 248° F. and the dienic polymer temperature.
[0026] The polymer composition of the present invention may be prepared by a process comprising a first contact polymerization stage of at least one vinyl aromatic monomer which is polymerizable by a catalytic system as that comprising a pre-catalyzer consisting of one or more compounds pertaining to the class of compounds such as titanium fluorenyl trialkoxyde (IV), and an activating compound selected from aluminum compounds obtained by trialkylaluminum hydrolysis and, more preferably, a methyl aluminoxane, such as that depicted in the patent application MX 9801717, in mass form or with the presence of a dissolvent selected from aromatic dissolvent and, more preferably, toluene, as well as from aliphatic dissolvents and, more preferably, 2,2,4-trimethyl pentane, or a mixture thereof, at a temperature between 32° F. and 194° F. for a period of time between 1 and 30 minutes; such a contact being followed by a second polymerization stage through subsequent addition of a dienic monomer at a temperature between 32° F. and 158° F. to form an unsaturated polymer composition.
[0027] The unsaturated polymer composition is polymerized for period of time between 10 minutes and 6 hours, and it is then mixed with an alcohol selected from aliphatic alcohols in order to end the polymerization reaction. In a preferred embodiment of the present invention, the aliphatic alcohol has from 1 to 4 carbon atoms, with isopropanol being preferred.
[0028] Once the reaction has come to an end, the composition is finally subjected to a stage of catalytic residue removal by using a mixture of an aliphatic alcohol and a solvent with at least one substituted or unsubstituted aromatic ring. In a preferred embodiment of the present invention, the aliphatic alcohol:aromatic solvent ratio is between 0.5:1 and 5:1, with a 1:1 ratio being preferred. The aliphatic alcohol from the stage of catalytic residue removal is preferably selected from alcohols having between 1 and 4 carbon atoms, preferably isopropanol, with the preferred aromatic solvent being toluene.
[0029] In an additional embodiment of the present invention, it has been surprisingly found that, at the end of the dienic monomer polymerization stage or once the dienic monomer has been converted at least by 50%, the non-hydrogenated polymer composition may be subjected to a hydrogenation stage in situ by direct contact with hydrogen at a partial hydrogen pressure between 10 and 150 psig and a temperature between 32° F. and 194° F. and, more preferably, a partial hydrogen pressure between 20 and 100 psig and a temperature between 68° F. and 158° F. It is yet more surprising that the hydrogenation stage of the non-hydrogenated polymer composition may be performed without the need of using additional hydrogenation catalyzers, which results in materials having up to 95% of hydrogenated polybutadiene.
[0030] The polymer composition of the present invention will be illustrated more clearly by the following examples, which are presented only as an illustration and thus do not limit the same.
[0031] Polymerization processes were performed according to what is depicted below.
EXAMPLES 1-9
[0032] A glass reactor with capacity of 600 mL, provided with a stirring system, a temperature and pressure control system, and a reagent addition system, was charged with a mixture of: 30 mL toluene, 30 mL of a vinyl aromatic monomer (see Chart II) and 3 g of a dry methylaluminoxane. The reactor was heated to 122° F. and was kept at this temperature for 10 minutes. Then, a solution of (C 9 H 13 )Ti(OC 3 H 7 ) 3 in 5 mL toluene was added. The vinyl aromatic monomer/titanium compound molar ratio was of 1000, while the Al/Ti ratio was of 250. The reactor jacket begins to cool down from the addition of the starter compound. 20 seconds after the beginning of polymerization, the reactor was added 200 ml toluene which was previously cooled to 50° F. At time t1 from the beginning of the polymerization (see Chart II), 60 mL butadiene were added. The reaction was left to proceed for 2 hours. The reactive mixture was mixed with 1 L isopropanol.
[0033] In order to remove the catalytic system residue, the product was extracted using the continuous extraction apparatus for 24 hours with a mixture of toluene-isopropanol at a 1:1 ratio, except for the case of Example 8, which has a higher content of the D component, of which the catalytic residue is part.
[0034] In order to characterize the product, the resin was separated into one hexane-soluble fraction and one hexane-insoluble fraction. According to the RMN analysis of 1 H and 13 C, the hexane-soluble fraction consists of polybutadiene having from 91 to 95% of 1,4-cis monomer units, with the rest being 1,2 monomer units. According to the RMN results for 1H, as well as RMN for 13 C and GPC, the hexane-insoluble fraction consists either of syndiotactic vinyl aromatic polymer block copolymer and highly 1,4-cis polybutadiene, or a mixture of syndiotactic vinyl aromatic polymer, syndiotactic vinyl aromatic polymer block copolymer, and highly 1,4-cis polybutadiene.
[0035] The characteristics of every polymer composition obtained are shown in Table II, which uses the same abbreviations as those in Table I.
TABLE I A It generally refers to the properties of the (syndiotactic vinyl aromatic)-(1,4-cis-dienic) copolymer B It generally refers to the 1,4-cis dienic polymer properties C It generally refers to the syndiotactic vinyl aromatic polymer properties D Organic and inorganic additives V Vinyl aromatic monomer St Styrene 4MeSt 4-methyl styrene 4BrSt 4-bromo styrene MeOSt 4-methoxy styrene 4NSt 4-dimethylamine styrene t1 Polymerization time for vinyl aromatic monomer, minutes M w A Molecular weight of A by weight cA, % Contents of 1,4-cis monomer units in A dienic blocks vA, % Contents by weight of A vinyl aromatic blocks PA, % Contents of copolymer A in the composition by weight M p B Peak molecular weight of B cB, % Contents of 1,4-cis monomer units PB, % Contents of B in the composition by weight M w C Molecular weight of C by weight PC, % Contents of C in the composition by weight PD, % Contents of D in the composition by weight Pv, % Total contents of the vinyl aromatic portion in the composition by weight SY, % Degree of syndiotacticity of the vinyl aromatic portion T g 1 First glass transition temperature T g 2 Second glass transition temperature T m Melting transition temperature ΔG′ Variation on the modulus of elasticity within the indicated temperature ranges
[0036]
TABLE II
EXAMPLE
Properties
1
2
3
4
5
6
7
8
9
V
St
St
St
St
St
St
St
4Me St
4Br St
t1
30
25
20
15
10
5
2.5
20
20
Component (A)
M w A, × 10E−3
245
267
201
202
176
207
96
295
304
cA, %
92
93
93
93
92
93
91
95
93
VA, %
96
84
53.2
95.5
72.7
82.2
58.9
60.4
40.2
PA, %
30.2
33.2
36.8
22.6
19.3
19.5
17.5
46.5
15.3
Component (B)
M p B, × 10E−3
246
231
256
385
485
450
284
233
297
cB, %
92.5
92.6
94.3
91.0
93
91
92.2
95
91.8
PB, %
66.2
64.8
55.0
76.5
78.9
80.0
79.5
39.4
67.6
Component (C)
M w C, × 10E−3
—
—
25.6
—
—
—
—
50.7
62.3
PC, %
0
0
7.1
0
0
0
0
10.3
14.6
Component (D)
PD, %
3.6
2
1.1
0.9
1.8
0.5
3
3.8
2.5
Properties
Pv, %
29.0
27.9
26.7
22.0
15.6
16.0
10.3
38.4
20.8
SY, %
99.9
99.9
99.9
99.9
99.9
99.9
99.9
98
96.6
Tg 1 , ° F.
−143.5
−143.5
−144.5
−140.9
−142.6
−143.3
−145.3
−147.2
−133.9
Tg 2 , ° F.
234
243.1
222
246.2
230
233
225
204
247.6
T m , ° F.
509
515
504.3
516.2
512
508
508.1
519.2
564.8
ΔG′, Mpa
From −76° F. to 194° F.
—
—
—
208.4-59
194-140
194-95
86-68
—
—
From 248° F. to 482° F.
—
—
—
39.2-37.4
77-59
44.6-39.2
44.6-42.8
—
—
EXAMPLES 10-18
[0037] A glass reactor with capacity of 600 mL, provided with a stirring system, a temperature and pressure control system, and a reagent addition system, was charged with a composed mixture of: 30 mL 2,2,4-trimethylpentane, 30 mL of a vinyl aromatic monomer (see Table III), and 3 g of a dry methylaluminoxane. The reactor was heated to 122° F. and was kept at this temperature for 10 minutes. Then, a solution of (C 9 H 13 )Ti(OC 3 H 7 ) 3 in 5 mL 2,2,4-trimethylpentane was added. The vinyl aromatic monomer/titanium compound molar ratio was of 1000, while the Al/Ti ratio was of 250. The reactor jacket begins to cool down from the addition of the starter compound. 20 seconds after the beginning of polymerization, the reactor was added 200 ml 2,2,4-trimethylpentane balanced to 68° F. At time t1 from the beginning of the polymerization (see Table III), 60 mL butadiene was added. The reaction was left to proceed for 2 hours. The reactive mixture was mixed with 1 L isopropanol.
[0038] In order to remove the catalytic system residue, the product was extracted using the continuous extraction apparatus for 24 hours with a mixture of toluene-isopropanol at a 1:1 ratio, except for the case of Example 10, which has a higher content of the D component, of which the catalytic residue is part.
[0039] In order to characterize the product, the resin was separated into one hexane-soluble fraction and one hexane-insoluble fraction.
[0040] According to the RMN analysis of 1 H and 13 C, the hexane-soluble fraction consists of polybutadiene having from 88 to 93% of 1,4-cis monomer units, with the rest being 1,2 monomer units.
[0041] According to the RMN results for 1 H, as well as RMN for 13 C and GPC, the hexane-insoluble fraction consists of a mixture of syndiotactic vinyl aromatic polymer, the syndiotactic vinyl aromatic polymer block copolymer, and highly 1,4-cis polybutadiene.
[0042] The characteristics of every polymer composition obtained are shown in Table III, which uses the same abbreviations as those in Table I.
TABLE III EXAMPLE Properties 10 11 12 13 14 15 16 17 18 V St St St St St St St St/ St/ MeOSt = 4NSt = 9/1 9/1 t1 30 25 20 15 10 5 2.5 15 5 Component (A) M w A, × 10E−3 248 201 220 195 151 175 499 193 333 cA, % 87.0 89.7 89.9 90.1 89.5 87.6 88.7 85 90.2 vA, % 76 71 58.5 59 53.5 43.5 40.5 10.5 21.5 PA, % 9.5 22.5 29.5 47.5 53.0 66.5 71.5 16.5 25.5 Component (B) M p B, × 10E−3 105 133 185 154 156 265 200 123 99 cB, % 88.7 90.6 91 89.2 90.3 89 88.1 93 91.8 PB, % 16.3 16.8 18.8 17.5 15.0 15.7 15.0 29.0 27.2 Component (C) M w C, × 10E−3 531 507 780 465 470 403 354 267 609 PC, % 70.2 57.2 51.1 32.0 31.0 14.2 10.5 51.1 44.8 Component (D) PD, % 4.0 3.5 2.8 3.0 1.0 3.6 3.0 3.4 2.5 Properties Pv, % 77.4 73.2 68.4 60.0 59.3 43.1 39.5 52.8 50.3 SY, % 99.9 99.9 99.9 99.9 99.9 99.9 99.9 98.2 97.1 Tg 1 , ° F. −131.8 −134.5 −130.5 −130.9 −131.9 −134.3 −130.1 −136.6 −133.9 Tg 2 , ° F. 239 241.1 242.6 235.7 239.9 238.1 248 200.3 249 T m , ° F. 530 532.4 528.8 536 539.6 525.2 516.2 491 554 ΔG′, Mpa From −76° F. to 194° F. — — — — — — 1832-1292 212-104 — From 248° F. to 482° F. — — — — — — 400-300 104-212 —
[0043] FIG. 1 compares the viscoelastic behavior of the polymer compositions of the present invention with that of a conventional SBR elastomer. It is clearly seen that the modulus of elasticity (G′) of the polymer composition of the present invention is maintained within the temperature range from −121° F. to 536° F., a range in which the material of the present invention does not flow. Conversely, a conventional elastomer loses its viscoelastic properties before the polystyrene-stage T g takes place, at about 158° F.
EXAMPLES 19-23
[0044] The process was the same as for Example 5. After 120 minutes of butadiene polymerization, the reactor was filled up with hydrogen at the partial pressure indicated in Table V and it was kept at such a pressure, as well as at the temperature shown in Table V for 24 hours. The reactive mixture was mixed with 1 L isopropanol.
[0045] In order to remove the catalytic system residue, the product was extracted using the continuous extraction apparatus for 24 hours with a mixture of toluene-isopropanol at a 1:1 ratio.
[0046] In order to characterize the product, the resin was separated into one hexane-soluble fraction, one hot heptane-soluble fraction, and one fraction that was insoluble in such dissolvents.
[0047] According to the RMN analysis of 1 H and 13 C, the hexane-soluble fraction consists of highly 1,4-cis polybutadiene.
[0048] According to the RMN analysis of 1 H and 13 C, the hot heptane-soluble fraction consists of hydrogenated polybutadiene.
[0049] According to the RMN results for 1 H, as well as RMN for 13 C and GPC, the fraction that was insoluble in both dissolvents consists of the syndiotactic polystyrene block copolymer and highly 1,4-cis hydrogenated polybutadiene.
[0050] The characteristics of every polymer composition obtained are shown in Table V, which uses the same abbreviations as those in Table IV.
EXAMPLES 24-27
[0051] The process was the same as for Example 14. After 120 minutes of butadiene polymerization, the reactor was filled up with hydrogen at the partial pressure indicated in Table V and it was kept at such a pressure, as well as at the temperature shown in Table V for 24 hours. The reactive mixture was mixed with 1 L isopropanol.
[0052] In order to remove the catalytic system residue, the product was extracted using the continuous extraction apparatus for 24 hours with a mixture of toluene-isopropanol at a 1:1 ratio.
[0053] In order to characterize the product, the resin was separated into one hexane-soluble fraction, one hot heptane-soluble fraction, and one fraction that was insoluble in such dissolvents.
[0054] According to the RMN analysis of 1 H and 13 C, the hexane-soluble fraction consists of highly 1,4-cis polybutadiene.
[0055] According to the RMN analysis of 1 H and 13 C, the hot heptane-soluble fraction consists of hydrogenated polybutadiene.
[0056] According to the RMN results for 1 H, as well as RMN for 13 C and GPC, the fraction that was insoluble in both dissolvents consists of a mixture of syndiotactic polystyrene, syndiotactic polystyrene block copolymer, and highly 1,4-cis hydrogenated polybutadiene.
[0057] The characteristics of every polymer composition obtained are shown in Table V, which uses the same abbreviations as those in Table IV.
TABLE IV A It generally refers to the properties of the (syndiotactic vinyl aromatic)-(1,4-cis-dienic hydrogenated) copolymer B It generally refers to the 1,4-cis dienic polymer properties BH It generally refers to the 1,4-cis dienic hydrogenated polymer C It generally refers to the syndiotactic vinyl aromatic polymer properties D Organic and inorganic additives P Hydrogen pressure in psig T, ° C. Hydrogenation temperature M w A Molecular weight of A by weight hA, % Fraction of hydrogenated monomer units in A dienic blocks PA, % Contents of copolymer A in the composition by weight M p B Peak molecular weight of B PB, % Contents of B in the composition by weight M w BH Molecular weight of BH by weight hBH, % Fraction of hydrogenated monomer units PBH, % Contents of BH in the composition by weight M w C Molecular weight of C by weight PC, % Contents of C in the composition by weight PD, % Contents of D in the composition by weight T g 1 First glass transition temperature T g 2 Second glass transition temperature T m Melting transition temperature ΔG′ Variation on the modulus of elasticity within the indicated temperature ranges
[0058]
TABLE V
EXAMPLE
Properties
19
20
21
22
23
24
25
26
27
P, psig
10
20
60
80
80
40
60
80
80
T. ° F.
68
158
122
122
158
104
122
122
158
Component (A)
M w A, × 10E−3
185
171
182
190
188
150
135
172
170
hA, %
0
27
68
86
95
5
44
71
89
PA, %
27
21
23
27
26
14
14
15
12
Component (B)
M p B, × 10E−3
263
151
128
101
360
133
105
71
287
PB, %
60
61
39
14
2
50
38
21
5
Component (BH)
M w BH, × 10E−3
15
65; 4
122; 3
120; 3
99; 1.5
3
131; 2.5
125; 2
102; 1.5
hBH, %
55
62
85
93
98
75
83
95
99
PBH, %
10
16
36
57
70
26
39
54
75
Component (C)
M w C, × 10E−3
—
—
—
—
—
465
482
290
472
PC, %
0
0
0
0
0
9
8
9
7
Component (D)
PD, %
2
2
2
2
2
1
1
1
1
Properties
ΔG′, Mpa
From −76° F. to 194° F.
—
176-95
—
—
—
44.6-33.4
—
—
—
From 284° F. to 482° F.
—
64.4-60.8
—
—
—
33.2-33.8
—
—
—
[0059] According to what has been depicted above, it may be seen that the polymer composition with elastomeric properties at wide temperature ranges of the present invention has been designed to comply with the requirements as of elastomeric properties that are needed for applications at a temperature range from −112° F. to 536° F., and it will be apparent for the one skilled in the art that the embodiments of the polymer composition depicted before and illustrated in the preceding examples, are only illustrative in purpose and do not limit the present invention, since may changes in details are possible without departing from the scope of the invention.
[0060] Although one specific embodiment of the invention has been illustrated and depicted, it must be emphasized that many modifications to the same are possible, such as the use of several additives, substituents of vinyl aromatic monomer, or various conjugated dienic monomers. Thus, the present invention shall not be construed to be restricted except for the requirements of the previous art and according to the appended claims and their interpretation according to the present detailed description.
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The invention relates to a polymeric composition having elastomeric properties over wide temperature ranges, of the type that comprises polymers and/of copolymers which are derived from substituted or non-substituted vinylaromatic monomers and compatible, homogeneous diene monomers. The inventive composition is based on stereoregular polymers and does not require the use of compatibilizer agents. The invention further relates to the method of obtaining said compositions and of hydrogenating same without the need for additional catalysts or methods.
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CROSS REFERENCE TO RELATED APPLICATION
This application is the U.S. National Stage of International Application No. PCT/EP2003/009569, filed Aug. 28, 2003 and claims the benefit thereof. The International Application claims the benefits of European Patent application No. 02020251.1 EP filed Sep. 10, 2002, both of the applications are incorporated by reference herein in their entirety.
FIELD OF THE INVENTION
The invention relates to a method for operating a steam generator in which the continuous heating panel of an evaporator is arranged in a heating gas channel which can be cross-flown in a more or less horizontal direction of a heating gas. Said continuous heating panel of the evaporator comprises a plurality of pipes of a steam generator which are connected in parallel to each other. Said pipes are constructed in such a way that they cross a flow medium and are provided with the part of a more or less vertical down pipe which can be cross-flown by the flow medium in a downward direction and with the part of a riser pipe connected downstream with respect to the down pipe on the flow medium side and which is more or less vertical and can be cross-flown by the flow medium in an upward direction in which case the continuous heating panel of the evaporator is arranged in such a way that one pipe of the steam generator which is hotter than the other pipe of the steam generator of the same continuous heating panel of the evaporator has a flow medium rate which is higher than that of the other pipe of the steam generator. It also relates to a steam generator for carrying out said method.
BACKGROUND OF THE INVENTION
In the case of a gas and steam turbine plant, the heat obtained from the operating means or the heating gas from the gas turbine is used to generate steam for the steam turbine. Heat is transferred to a waste-heat steam generator connected downstream of one of the gas turbines in which a plurality of heating panels are usually arranged to preheat the water in order to generate and superheat the steam. The heating panels are connected to the water-steam cycle of the steam turbine. The water-steam cycle usually includes a number of pressure stages, for example three, in which case, each pressure stage can feature an evaporator heating panel.
For the steam generator connected downstream on the heating gas side of the gas turbine as a waste-heat steam generator, several alternative embodiment concepts can be taken into consideration, namely, the embodiment as a continuous steam generator or the embodiment as a circulation steam generator. In the case of a continuous steam generator, when the steam generator pipes provided as evaporator pipes are heated, the flow medium in the steam generator pipes evaporates in a single through-flow. However, by contrast with this, in the case of a natural or forced circulation steam generator, the circulating water is only partially evaporated when flowing through the evaporator pipes. The water not evaporated in this case is again supplied to the same evaporator pipes for further evaporation after the generated steam has been separated.
Unlike a natural or forced circulation steam generator, the continuous steam generator is not subjected to a pressure limit so that in the case of initial steam pressures it can be embodied to exceed the critical pressure of water by far (P Kri ≈221 bar), in which case, it is not possible to differentiate between the water phase and the steam phase and, as a result, a phase separation is also not possible. A high initial steam pressure favors a high thermal degree of effectiveness and, therefore, low CO 2 emissions of a fossil-heated power plant. In addition, a continuous steam generator compared to a circulation steam generator has a simple embodiment and can, as a result, be manufactured particularly cost-effectively. Therefore, the application of a steam generator embodied according to the through-flow principle as a waste-heat steam generator of a gas and steam turbine plant is, in this case, particularly favorable for obtaining a high overall degree of effectiveness of the gas and steam turbine plant with a simple embodiment.
Particular advantages with respect to manufacturing costs, but also with respect to maintenance work are offered by the horizontal waste-heat steam generator, for which the heating medium or the heating gas, that is the waste gas from the gas turbine is cross-flown in a more or less horizontal direction of flow through the steam generator. However, in the case of a horizontal steam generator, the steam generator pipes of a heating panel of the evaporator can, depending on their positioning, be exposed to greatly varying heating temperatures. Particularly in the case of the steam generator pipes of a continuous steam generator connected on the outlet side to a common accumulator, a different heating of the individual steam generator pipes, in each case, can lead to a joining together of the steam flows with the steam parameters deviating strongly from one another and, as a result, to undesirable losses in the efficiency, particularly to a relatively drop in efficiency of the heating panel involved and resulting reduced steam generation. A difference in heating of neighboring steam generator pipes can, in addition, damage the steam generator pipes or the accumulator particularly in the joining area of the accumulators in each case. Thus the desirable application of a horizontal continuous steam generator, in itself, embodied as a waste-heat steam generator for a gas turbine may cause considerable problems with respect to a sufficiently stabilized flow control.
From EP 0 944 801 B1, a steam generator designed for horizontal use is known and it also has the above-mentioned advantages of a continuous steam generator. In addition to this, the heating panel of the evaporator of the known steam generator is arranged as a continuous heating panel and is embodied in such a way that one pipe of the steam generator which is hotter than the other pipe of the steam generator of the same continuous heating panel of the evaporator has a flow medium rate which is higher than that of the other pipe of the steam generator. Thus, the continuous heating panel generally means a heating panel which is embodied for a cross-flow according to the through-flow principle. The flow medium supplied to the heating panel of the evaporator arranged as the continuous heating panel, therefore, completely evaporates in a single through-flow in each case through this continuous heating panel or through a heating panel system comprising a plurality of continuous heating panels which are connected in series to each other.
The evaporator panel of the evaporator of the known steam generator arranged as a continuous heating panel therefore shows, in the nature of the flow characteristics of a heating panel of a natural circulation evaporator (natural circulation characteristics) in the case of a different heating of the individual pipes of a steam generator, a self-stabilizing behavior, which without the requirement of external influences adjusts the temperatures on the outlet side even in the case of differently heated pipes of the steam generator which are connected in parallel on the flow medium side.
For this design of steam generator, in order to obtain a particularly low load through thermally-related stresses particularly in relation to the manufacturing and assembly costs kept particularly low in relation to the distribution of the flow medium on the water side and/or the steam side, the continuous heating panel of the evaporator of the steam generator can be designed as U-shape comprising a plurality of pipes of a steam generator which are connected in parallel to each other for through-flow of the flow medium, which each feature an almost vertically arranged down pipe section through which the flow medium can flow in a downwards direction and connected downstream from this on the flow medium side an almost vertically arranged riser pipe through which the flow medium can flow in an upwards direction. As has been shown, with this type of design, a pressure contribution through the geodetical pressure of the water column in the down pipe of the specific pipe of the steam generator can be utilized in a way that favors and promotes flow when the continuous heating panel is cross-flown.
However, such a design could basically promote the occurrence of flow instabilities on operating the continuous heating panel of the evaporator which could bring about operational disadvantages. Although supplying the pipes of the steam generator forming the continuous heating panel with a relatively low mass flow rate density and the relatively low frictional pressure loss associated with these allows the natural circulation characteristics of the flow in the pipe of the steam generator to be obtained, which has a stabilizing effect on the flow. Nevertheless, it is also desirable especially in the case of such a design with a pipe section which can be cross-flown downwards to contribute, to a particular extent to stabilizing the flow ratios when the continuous heating panel of an evaporator is operated.
SUMMARY OF THE INVENTION
Therefore, it is the object of the invention to specify a method for operating a steam generator of the type stated above in which in a relatively simple manner an especially high level of flow stability can be achieved during operation of the continuous heating panel of the evaporator. In addition a steam generator of the type stated above which is particularly suitable for carrying out the method should be specified.
With regard to the method, this object of the invention is achieved by the flow medium being supplied to the continuous heating panel of the evaporator in such a way that in the down pipe section of the relevant steam generator pipe it has a flow velocity which is higher than a pre-specified minimum flow velocity.
Thus, the invention takes as its starting point the consideration that a particularly high flow stability and thereby an exceedingly high degree of operational safety for the said steam generator can be obtained by explicitly suppressing possible causes for flow instabilities occurring. As has been shown, an occurrence of steam bubbles in the down pipe of the specific steam generator pipe can be considered to be one of these possible causes. However, if steam bubbles should be formed in a part of the down pipe, these could rise in the water column in the down pipe and therefore move against the direction of flow of the flow medium. The explicit suppression of such a movement of possibly occurring steam bubbles flowing against the direction of flow of the flow medium should by means of a suitable specification of the operating parameters ensure a forced entrainment of the steam bubbles in the actual direction of flow of the flow medium. This can be achieved by supplying the continuous heating panel of the evaporator with a flow medium in a suitable way in which case a sufficiently high flow velocity of the flow medium in the pipes of the steam generator brings about the desired entrainment effect on the steam bubbles possibly already there or any bubbles formed.
In this case the flow velocity of the flow medium in the part of the down pipe of the specific pipe of the steam generator is advantageously set in such a way that in the permissible operating area, an entrainment of possibly occurring steam bubbles is guaranteed in any event. For this purpose, the flow velocity required for the entrainment of the steam bubbles is advantageously predefined as the minimum velocity for the flow velocity of the flow medium in the part of the down pipe of the specific pipe of the steam generator and possibly increased by means of a suitably selected margin of safety.
A sufficiently high flow velocity of the flow medium in the part of the down pipe of the specific pipe of the steam generator can be set in a particularly easy way by supplying the flow medium to the part of the down pipe of the specific pipe of the steam generator in the partially evaporated state and/or with a certain minimum enthalpy. For this purpose, the flow medium is advantageously partially pre-evaporated before entering the continuous heating panel of the evaporator in such a way that, on entering the continuous heating panel of the evaporator, it has a steam content and/or an enthalpy of more than one predefined minimum steam content or a predefined minimum enthalpy.
As regards the steam generator, said object of the invention is achieved in that the continuous heating panel of the evaporator is connected upstream of the further continuous heating panel of the evaporator on the flow medium side.
This means that the evaporator system of the steam generator is embodied as a multi-stage design in which case the further continuous heating panel of the evaporator is provided as a pre-evaporator in order to suitably condition the flow medium before it enters the actual continuous heating panel of the evaporator. By contrast, the actual continuous heating panel of the evaporator is used as a kind of second evaporator stage in order to complete the evaporation of the flow medium.
Expediently the further continuous heating panel of the evaporator is in itself also arranged for a self-stabilizing flow behavior by means of the consistent utilization of the natural circulation characteristics in the specific pipes of the steam generator. For this purpose, the further continuous heating panel of the evaporator advantageously comprises a plurality of pipes of a steam generator which are connected in parallel to each other and said pipes are constructed in such a way that they cross a flow medium. Expediently the continuous heating panel of the evaporator is arranged in such a way that one pipe of the steam generator which is hotter than the other pipe of the steam generator of the same continuous heating panel of the evaporator has a flow medium rate which is higher than that of the other pipe of the steam generator. It also relates to a steam generator for carrying out said method.
In order to reliably ensure that the desired effect of a consistent entrainment of steam bubbles possibly occurring in the part of a down pipe of a pipe of the steam generator of the continuous heating panel of the evaporator, the further continuous heating panel of the evaporator is expediently dimensioned in such a way that during operation, the flow medium flowing into the continuous heating panel of the downstream evaporator has a flow velocity which is higher than a minimum flow velocity required for the entrainment of the steam bubbles.
While the continuous heating panel of the evaporator of the steam generator is formed from the said u-shaped pipes of the steam generator, the further continuous heating panel of the evaporator is formed, in order to avoid obstructions there by possibly occurring steam bubbles and expediently, by steam generator pipes so that the flow medium can flow from below in an upward direction. The further continuous heating panel of the evaporator is in particular thereby exclusively formed from riser pipe parts.
With this type of design of the steam generator, the further continuous heating panel of the evaporator is, expediently, provided with a plurality of outlet accumulators arranged above the heating gas for the flow medium. For a concept kept especially simple as regards the outlet-side homogenizing of the flow medium flowing from the further continuous heating panel of the evaporator, the outlet accumulator connected downstream on the flow medium side is advantageously aligned with its longitudinal axis essentially parallel to the direction of a heating gas.
With this type of design, the characteristic of the further continuous heating panel of the evaporator provided in any event, namely a self-stabilizing circulation characteristic, is explicitly used for the simplification of the distribution. Precisely because of the self-stabilizing circulation characteristic, it is possible for the pipes of a steam generator connected in series and as a result heated differently, namely, also seen in the direction of a heating gas, to each case join a common outlet accumulator on the outlet side under more or less the same steam conditions. The flow medium flowing from the pipes of the steam generator is mixed in this unit and provided for forwarding to a subsequent heating panel system without adversely affecting the homogenizing obtained during the mixing process. Therefore, a special, relatively costly distribution system connected downstream of the continuous heating panel is not required.
For a design kept relatively simple the further continuous heating panel of the evaporator comprises, preferably in the form of a bundle of pipes, a plurality of pipe sets connected in series seen in the direction of a heating gas, each one of which is formed from a plurality of pipes of a steam generator connected next to one another in the direction of a heating gas. In essence, the subsequent distribution of the flow medium to the further continuous heating panel of the evaporator by saving on a costly distribution system can be embodied particularly simply while in the further advantageous embodiment of the further continuous heating panel of the evaporator a corresponding plurality of outlet accumulators aligned with their longitudinal axis parallel to the direction of a heating gas are allocated to a plurality of pipes of a steam generator in each pipe set. Therefore, in each case a pipe of the steam generator of each pipe set now joins each outlet accumulator. The outlet accumulators are advantageously arranged above the heating gas channel.
Because of the essentially u-shaped design of the pipes of the steam generator forming the continuous heating panel of the evaporator, their inflow area is in the top area or above the heating gas channel. In essence, both the consistent utilization of the outlet accumulators allocated to the further continuous heating panel of the evaporator and said accumulators arranged above the heating gas channel which are in each case aligned with their longitudinal direction parallel to the direction of flow of a heating gas, in particular, make possible a cost-effective interconnection of the continuous heating panel of the evaporator to the further continuous heating panel of the evaporator by integrating the outlet accumulator or each outlet accumulator of the further continuous heating panel of the evaporator in an advantageous embodiment with a downstream continuous heating panel of the evaporator allocated to the inlet accumulator in each case in a constructional unit on the flow medium side.
Such an arrangement makes possible direct overflowing of the flow medium emerging from the further continuous heating panel of the evaporator in the pipes of the steam generator connected downstream on the flow medium side of the continuous heating panel of the evaporator said in the first instance. In this arrangement, transfer of the flow medium flowing from the further continuous heating panel of the evaporator into the continuous heating panel of the evaporator is possible almost without adversely affecting the homogenization achieved by mixing in the outlet collector of the further continuous heating panel. Costly distributor or connection lines between the outlet accumulator of the further continuous heating panel and the inlet accumulator of the continuous heating panel as well as the allocated mixing and distribution elements can thus be dispensed with and generally line routing is relatively simple.
In a further advantageous embodiment, the pipes of the steam generator of the continuous heating panel of the evaporator are connected on the inlet side to a common plane aligned parallel to the longitudinal direction of the accumulator units to which the inlet accumulators are connected in each case. This type of arrangement ensures that the partially evaporated flow medium to be fed to the continuous heating panel of the evaporator, starting from the part used as the outlet accumulator for the further continuous heating panel of the evaporator of the integrated unit, first of all collides with the bottom of the part of the constructional unit used as the inlet accumulator for the continuous heating panel of the evaporator and is once again subjected to turbulence there and subsequently, with almost the same two-phase components, flows away into the pipes of the steam generator of the continuous heating panel of the evaporator connected to the specific inlet accumulator. As a result of the symmetrical arrangement of the outlet points from the relevant inlet accumulator viewed in the direction of flow of the accumulator units there is particularly homogeneous feed of flow medium to the continuous heating panel.
Expediently, the steam generator is used as a waste-heat steam generator of a gas and steam turbine plant. For this purpose, the steam generator is advantageously connected downstream of the heating gas side of a gas turbine. With this circuit, an additional firing in order to increase the heating gas temperature can expediently be arranged behind the gas turbine.
The advantages obtained with the invention are to be found especially in the fact that the at least partial pre-evaporation of the flow medium now provided before it flows into the continuous heating panel made up essentially of u-shaped pipes of the steam generator, means that a desired steam content and/or a desired enthalpy of the flow medium can be set according to predefined criteria. By suitably selecting the steam content and/or the enthalpy of the flow medium flowing into the continuous heating panel above a predefined minimum steam content and/or a predefined minimum enthalpy, a sufficient flow velocity of the flow medium in the part of the down pipe of the specific pipe of the steam generator of the continuous heating panel can be ensured. The flow velocity of a water-steam mixture is, in particular, in the case of an equal mass through-flow the higher, the greater the steam content, and in this way forms the specific volume of the mixture.
In this case the flow velocity of the water-steam mixture can in particular be set high enough for possible steam bubbles occurring in the part of the down pipe of the specific pipe of the steam generator to reliably be entrained and can be transported in the part of the riser pipe connected downstream of the specific part of the down pipe. Even in the case of the u-shaped embodiment of the pipes of the steam generator of the continuous heating panel of the evaporator, a movement of the steam bubbles away from the flow direction of the flow medium is securely prevented so that a particularly high flow stability and as a result a particularly high operational safety for the steam generator with a continuous heating panel of the evaporator designed in this way is guaranteed.
BRIEF DESCRIPTION OF THE DRAWINGS
An embodiment of the invention is explained in greater detail with reference to the accompanying drawings. They are as follows:
FIG. 1 a simplified, longitudinal sectional view of the evaporator section of a horizontal steam generator,
FIG. 2 a sectional view from above of the steam generator according to FIG. 1 ,
FIG. 3 sectional view of the steam generator according to FIG. 1 along the line of cut shown in FIG. 2 ,
FIG. 4 sectional view of the steam generator according to FIG. 1 along the line of cut shown in FIG. 2 , and
FIG. 5 an enthalpy or mass flow rate diagram of the flow velocity.
In all the figures, the same reference symbols are allocated to the same parts.
DETAILED DESCRIPTION OF THE INVENTION
The steam generator 1 shown in FIG. 1 with an evaporator section is connected downstream, on the waste gas side as a waste-heat steam generator, of a gas turbine which is not shown in greater detail. The steam generator 1 has an enclosing wall 2 which forms a heating gas channel 6 which can be cross-flown in a more or less horizontal direction of a heating gas x indicated by means of arrows 4 for the waste gas from the gas turbine. Said heating gas channel 6 comprises a plurality—two in the embodiment—of continuous heating panels of the evaporator 8 , 10 embodied according to the through-flow principle which are connected in series for the through-flow of a flow medium W, D.
The multi-stage evaporator system formed from the continuous heating panels of the evaporator 8 , 10 can be subjected to a non-evaporated flow medium W which evaporates in the case of a single through-flow through the continuous heating panels of the evaporator 8 , 10 and, after flowing from the continuous heating panel of the evaporator 8 , is discharged as steam D and usually supplied to the superheater panels for superheating. The evaporator system formed from the continuous heating panels of the evaporator 8 , 10 is arranged in the water-steam cycle of a steam turbine not shown in greater detail. In addition to this evaporator system, a plurality of other heating panels are arranged in the water-steam cycle of the steam turbine (not shown in greater detail in FIG. 1 ) in the case of which these may be, for example, a superheater, medium-pressure evaporator, low-pressure evaporator and/or a preheater.
The continuous heating panel of the evaporator 8 of the steam generator 1 comprises a plurality of pipes of a steam generator 12 as a bundle of pipes which are connected in parallel to each other. Said pipes are constructed in such a way that they cross a flow medium W. Thus, a plurality of pipes of a steam generator 12 are seen in each case with the formation of a so-called pipe set in the direction of a heating gas x which is arranged side-by-side so that only one of the pipes of the steam generator 12 of a pipe set is arranged side-by-side in such a way as can be seen in FIG. 1 . On the flow medium side, an inlet accumulator 14 connected upstream in each case and a common outlet accumulator 16 connected downstream in each case are allocated to the pipes of the steam generator 12 which are arranged side-by-side.
The continuous heating panel of the evaporator 8 is embodied in such a way that it is suitable for supplying the pipes of the steam generator 12 with a relatively low mass flow rate density in which case the pipes of the steam generator 12 have natural circulation characteristics. In the case of these natural circulation characteristics, the continuous heating panel of the evaporator is arranged in such a way that one pipe of the steam generator 12 which is hotter than the other pipe of the steam generator 12 of the same continuous heating panel of the evaporator 8 has a flow medium W rate which is higher than that of the other pipe of the steam generator. In order to ensure this, in particular, with simple constructional means in a particularly reliable way, the continuous heating panel of the evaporator 8 comprises two segments which are connected in series on the flow medium side. In the first segment, each pipe of the steam generator 12 of the continuous heating panel 8 is provided with the part of a more or less vertical down pipe 20 which can be cross-flown by the flow medium W in a downward direction. In a second segment, each pipe of the steam generator 12 is provided with the part of a riser pipe 22 connected down-stream with respect to the part of the down pipe 20 on the flow medium side and which is more or less vertical and can be cross-flown by the flow medium W in an upward direction.
In this case the part of the riser pipe 22 is connected to the part of the down pipe 20 allocated to it via a part of the overflow 24 .
Each pipe of the steam generator 12 of the continuous heating panel of the evaporator 8 has an almost u-shaped form (as can be seen in FIG. 1 ) in which case the bend of the U is formed by the part of the down pipe 20 and the part of the riser pipe 22 and the connection elbow by the part of the overflow 24 . In the case of such a pipe of the steam generator 12 embodied in such a way, the geodetical pressure generates the pressure contribution of the flow medium W in the area of part of the down pipe 20 —by contrast with the area of the part of the riser pipe 22 —thus, a flow-promoting and not a flow-inhibiting pressure contribution. In other words: The water column of the non-evaporated flow medium W in the part of the down pipe 20 still carries on “thrusting forward” the cross-flow of the specific pipe of the steam generator 12 instead of preventing this from happening. This means that the pipe of the steam generator 12 all in all has a relatively low loss in pressure.
In the case of a more or less u-shaped design, each pipe of the vertical steam generator 12 is in each case in the inlet area of its part of the down pipe 20 and the outlet area of its part of the riser pipe 22 suspended from or fastened to the top of the heating gas channel 6 . Seen from a point of view in space, the bottom ends of the specific part of the down pipe 20 and the specific part of the riser pipe 22 which are interconnected by means of their part of an overflow 24 are, on the other hand, not fastened directly in space to the heating gas channel 6 . Therefore, extensions of lengths of these segments of the pipes of the steam generator 12 can be tolerated without a risk of being damaged, in which case the specific part of the overflow 24 acts as an extension elbow. This arrangement of the pipes of the steam generator 12 is, as a result, particularly flexible and, with respect to the thermal voltages, is also insensitive to the differential expansions occurring.
However, in the case of a horizontal steam generator 1 and by using the continuous heating panel of the evaporator 8 with, in essence, u-shaped pipes of the steam generator 12 , steam bubbles in general still occur in the part of the down pipe 20 of a steam generator 12 . However, it is possible that these steam bubbles could rise against the direction of flow of the flow medium W in the specific part of the down pipe 20 and, therefore, adversely affect the stability of the flow and also the reliable operation of the steam generator 1 . In order to exclude this in a reliable way, the steam generator 1 is embodied to supply the continuous heating panel of the evaporator 8 with a flow medium W which has already been partially evaporated.
For this purpose, the flow medium D, W of the continuous heating panel of the evaporator 8 is supplied in such a way that the flow medium D, W in the part of the down pipe 20 of the specific pipe of the steam generator 12 has a flow velocity which is higher than a minimum flow velocity predefined in the down pipe. On the other hand, this is again measured in such a way that on the basis of the sufficiently high flow velocity of the flow medium D, W in the part of the down pipe 20 , the steam bubbles occurring there are reliably entrained in the direction of flow of the flow medium D, W and are transported via the specific part of the overflow 24 to the part of the riser pipe 22 connected downstream in each case. For this purpose, the adherence to a sufficiently high flow velocity of the flow medium D, W in the parts of the down pipe 20 of the pipes of the steam generator 12 is guaranteed by means of the fact that the supply of the flow medium D, W to the continuous heating panel of the evaporator 8 is, for this purpose, provided with a sufficiently high steam content and/or with a sufficiently high enthalpy.
Therefore, in order to make possible the supply of the flow medium D, W with suitable parameters in the already partially evaporated condition, the continuous heating panel of the evaporator 8 of the steam generator 1 is connected upstream on the flow medium side as the further continuous heating panel of the evaporator 10 . Therefore, the continuous heating panel of the evaporator 10 is embodied as a pre-evaporator so that the evaporator system is formed by the further continuous heating panel of the evaporator 10 which is connected downstream with respect to the continuous heating panel of the evaporator 8 on the flow medium side. Therefore, the further continuous heating panel of the evaporator 10 provided as a pre-evaporator is then arranged in space in a relatively lower-temperature range of the heating gas channel 6 and, as a result, on the side of the heating gas downstream of the continuous heating panel of the evaporator 8 . On the other hand, the continuous heating panel of the evaporator 8 is arranged closer to the inlet area of the heating gas channel 6 for the heating gas flowing from the gas turbine and, as a result, is exposed in operating cases to a relatively high thermal input because of the heating gas.
The further continuous heating panel of the evaporator 10 is for its part also formed by a plurality of pipes of a steam generator 30 which are connected in parallel to each other so that they cross a flow medium W. Therefore, the pipes of the steam generator 30 , in essence, are arranged with their longitudinal axis in such a way that they are more or less vertical and are constructed in such a way that they cross a flow medium W from a bottom inlet area to a top outlet area, thus from the bottom to the top. In order to also guarantee a particularly high stability of the cross-flow for the further continuous heating panel of the evaporator 10 as a self-stabilizing action, the continuous heating panel of the evaporator 10 is also arranged in such a way that one pipe of the steam generator 30 which is hotter than the other pipe of the steam generator 30 of the same continuous heating panel of the evaporator has a flow medium W rate which is higher than that of the other pipe of the steam generator 30 .
In order to guarantee, according to the concept envisaged for the evaporator system formed by the continuous heating panel of the evaporator 8 and by the further continuous heating panel of the evaporator 10 which is connected upstream with respect to this, namely the embodiment which on the inlet side, supply the continuous heating panel of the evaporator 8 with a partially pre-evaporated flow medium D, W which has a sufficiently high steam content and/or a sufficiently high enthalpy, the further continuous heating panel of the evaporator 10 is suitably dimensioned. In this case, a suitable material selection and a suitable dimensioning of the pipes of the steam generator 30 must in particular be considered comparatively to each other and possibly also varying from each other, but a suitable positioning of the pipes of the steam generator 30 must also be considered. Specifically with a view to these parameters, the further continuous heating panel of the evaporator 10 is dimensioned in such a way that in operating cases the flow medium D, W flowing into the downstream continuous heating panel of the evaporator 8 has a flow velocity which is higher than a minimum flow velocity required for the entrainment of the steam bubbles occurring in the respective parts of the down pipe 20 .
As has been shown, the high operational safety aimed at in the embodiment can, in essence, be achieved to a large extent, by equally distributing the heat absorption in operating cases on the continuous heating panel of the evaporator 8 and on the further continuous heating panel of the evaporator 10 . The continuous heating panels of the evaporator 8 , 10 and the pipes of the steam generator 12 , 30 forming the said continuous heating panels of the evaporator are, as a result, dimensioned in such a way in the embodiment that in operating cases the overall thermal input into the pipes of the steam generator 12 forming the continuous heating panel of the evaporator 8 more or less conforms to the thermal input into the pipes of the steam generator 30 forming the further continuous heating panel of the evaporator 10 . With due regard to the resulting mass flow rates, the further continuous heating panel of the evaporator 10 therefore has a suitably selected plurality of pipes of a steam generator 30 with a view to a plurality of pipes of a steam generator 12 of the continuous heating panel 8 connected downstream on the flow medium side.
The pipes of the steam generator forming the further continuous heating panel of the evaporator 10 are embodied for a cross-flow of the flow medium W from the bottom to the top. In this case, the further continuous heating panel of the evaporator 10 comprises as a bundle of pipes, a plurality of pipe sets 32 seen in the direction of a heating gas x, and arranged side-by-side, each one of which is formed from a plurality of pipes of a steam generator 30 seen in the direction of a heating gas x arranged side-by-side and of which only one pipe of the steam generator 30 can be seen in FIG. 1 . Thus, one common inlet accumulator 34 is connected upstream of the pipes of the steam generator 30 of each pipe set 32 , said inlet accumulator 34 , in essence, being aligned with its longitudinal axis vertical to the direction of a heating gas x. As a result, the inlet accumulators 34 are connected to a water supply system 36 only shown diagrammatically in FIG. 1 which can comprise a distribution system for the tailor-made distribution of the inflow of the flow medium W into the inlet accumulator 34 .
On the outlet side and, therefore, in an area above the heating gas channel 6 , the pipes of the steam generator 30 forming the further continuous heating panel of the evaporator 10 in each case join a plurality of allocated outlet accumulators 38 . In essence, each one of the outlet accumulators 38 arranged parallel and side-by-side to each other, of which only one can be seen in FIG. 1 , is aligned with its longitudinal axis, in essence, parallel to the direction of a heating gas x. In this case, a plurality of outlet accumulators 38 is adapted to a plurality of pipes of a steam generator 30 in each pipe set 32 .
An inlet accumulator 14 is allocated to each outlet accumulator 38 of the continuous heating panel of the evaporator 8 connected downstream to the further continuous heating panel of the evaporator 10 on the flow medium side. On the basis of the u-shaped embodiment of the continuous heating panel of the evaporator 8 , the specific inlet accumulator 14 is arranged, in the same way as the specific outlet accumulator 38 , above the heating gas channel 6 . The continuous heating panel of the evaporator 8 can then be connected in series to the further continuous heating panel of the evaporator 10 in a particularly easy way by integrating each outlet accumulator 38 in the allocated inlet accumulator 14 in a constructional unit 40 in each case. By means of the structural or constructional unit 40 , a direct overflow of the flow medium W of the further continuous heating panel of the evaporator 10 is allowed in the continuous heating panel of the evaporator 8 without a relatively expensive distribution or connection system being necessary.
As is shown in the overhead cross-sectional view of FIG. 2 , the pipes of the steam generator 30 in each case of two neighboring pipe sets 32 seen in a vertical direction of a heating gas x are arranged in a staggered way, so that with regard to the arrangement of the pipes of a steam generator 30 , a rhombic basic pattern is, in essence, obtained as a result. In the case of this arrangement, the outlet accumulators 38 , of which only one is shown in FIG. 2 , are positioned in such a way that one pipe of the steam generator 30 from each pipe set 32 joins each outlet accumulator 38 in each case. In this case, it can also be identified that each outlet accumulator 38 with an allocated inlet accumulator 14 for the continuous heating panel of the evaporator 8 connected downstream of the further continuous heating panel of the evaporator 10 , is integrated in a constructional unit 40 .
It can, in addition, be taken from FIG. 2 that the pipes of the steam generator 12 forming the continuous heating panel of the evaporator 8 also form a plurality of pipe sets seen lying behind one another in the direction of a heating gas x, in which case the first two pipe sets seen in the direction of a heating gas x are formed from the parts of the riser pipe 22 of the pipes of the steam generator 12 which on the outlet side in each case join the outlet accumulator 16 for the evaporated flow medium D. The next two pipe sets seen in the direction of a heating gas x are formed, on the other hand, from the parts of the down pipe 20 of the pipes of the steam generator 12 which on the inlet side are connected to an allocated inlet accumulator 14 in each case.
FIG. 3 shows in a sectional side view, the inlet area of the pipes of the steam generator 12 and the outlet area of the pipes of the steam generator 30 in the allocated constructional unit 40 in each case, which comprises, on the one hand, the outlet accumulator 38 for a plurality of pipes of a steam generator 30 forming the further continuous heating panel of the evaporator 10 and, on the other hand, includes the inlet accumulator 14 for two of the pipes of a steam generator 12 forming the continuous heating panel of the evaporator 8 in each case. From this view it is in particular clear that a flow medium D, W flowing from the pipes of the steam generator 30 and entering the outlet accumulator 38 can overflow directly into the inlet accumulator 14 allocated to the continuous heating panel of the evaporator 8 . When the flow medium D, W overflows, this then first of all collides with a base plate 42 of the constructional unit 40 comprising the inlet accumulator 14 . As a result of this collision there is a turbulence and, in particular, a thorough mixing of the flow medium D, W, before this passes over from the inlet accumulator 14 into the parts of the down pipe 20 of the allocated pipes of a steam generator 12 .
As can also still clearly be seen in the view according to FIG. 3 , the part of the constructional unit 40 on the end side embodied as the inlet accumulator 14 for the pipes of a steam generator 12 is designed in such a way that the flow medium W flows into the pipes of a steam generator 12 for all the pipes of a steam generator 12 from a single plane vertical to the longitudinal direction of the constructional unit 40 . In order to make this possible also for two pipes of a steam generator 12 which, with regard to their actual positioning in space, to which two different pipe sets arranged behind one another seen in the direction of a heating gas x must be allocated, a part of the overflow 46 is, in each case, allocated to each pipe of a steam generator 12 . Each part of the overflow 46 then slopes in the direction of a heating gas x and connects the top area of the pipe of an allocated steam generator 12 to the specific outlet opening 48 of the inlet accumulator 14 in each case. By means of this arrangement, all the outlet openings 48 of the inlet accumulator 14 can be positioned in a common plane vertical to the cylinder axis of the constructional unit 40 so that already on the basis of the symmetrical arrangement of the outlet openings 48 , in relation to the flow path of the flow medium D, W, an equal distribution of the flow medium D, W flowing into the pipes of a steam generator 12 is guaranteed.
In order to further explain the pipe layouts in the area of their inlets or outlets in the constructional unit 40 or from the constructional unit 40 , a plurality of such constructional units 40 is shown in FIG. 4 as a front view, in which case the line of cut designated with IV in FIG. 2 is used as the starting basis. In this case, it can also be identified that the two constructional units 40 shown on the left in FIG. 4 which in the area of their end, embodied as the inlet accumulator 14 for the downstream pipes of a steam generator 12 are in each case connected via the parts of the overflow 46 to the parts of the down pipe 20 connected downstream of the pipes of a steam generator 12 .
In comparison with this, the two constructional units 40 shown on the right in FIG. 4 , in each case shown in the vicinity of their front area embodied as the outlet accumulator 38 for the pipes of a steam generator 30 of the further continuous heating panel of the evaporator 10 are shown. In this case, it can be taken from the drawing that the pipes of a steam generator 30 joining the pipe sets 32 lying behind one another in the constructional unit 40 in each case pass into the constructional unit 40 at simple angles.
The steam generator 1 according to FIG. 1 and with the special embodiments according to FIGS. 2 to 4 is embodied for a safe operation of the continuous heating panel of the evaporator 8 in particular. In this case, when operating the steam generator 1 it is, in essence, ensured that the flow medium D, W of the continuous heating panel of the evaporator 8 which is u-shaped is supplied in such a way that the flow velocity thereof is higher than a minimum flow velocity predefined in the down pipe. This results in the fact that the steam bubbles occurring in the parts of the down pipe 20 of the pipes of a steam generator forming the continuous heating panel 8 are entrained and carried into the part of the riser pipe 22 connected downstream in each case. In order to ensure a sufficiently high flow velocity of the flow medium D, W flowing into the continuous heating panel of the evaporator 8 , the continuous heating panel of the evaporator 8 is supplied by using the further continuous heating panel of the evaporator 10 connected upstream to it in such a way that the flow medium D, W flowing into the continuous heating panel of the evaporator 8 has a steam content or an enthalpy which is higher than that of a predefinable minimum steam content or higher than a predefinable minimum enthalpy. In order to adhere to the operating parameters which are suitable for this, the continuous heating panels of the evaporator 8 , 10 are embodied or dimensioned in such a way that in all the operating points, the steam content or the enthalpy of the flow medium D, W on entering the continuous heating panel of the evaporator 8 is above the suitably predefined characteristics as shown, for example, in FIGS. 5 a , 5 b.
FIGS. 5 a , 5 b show as a family of curves with the operating pressure as the family of parameters, the functional dependency of the minimum steam content X min to be set or the minimum enthalpy H min to be set as a function of the embodiment according to the selected mass flow rate density m. In this case, curve 70 represents the criterion of the embodiment for an operating pressure of p=25 bar in each case, whereas curve 72 is provided for an operating pressure of p=100 bar in each case.
Therefore, it is possible to identify from this family of curves that, for example, during a part load operation in the case of an embodiment of the mass flow rate density m of 100 kg/m 2 s and a provided operating pressure of p=100 bar, it should be ensured that the steam content X min in the flow medium W that flows into the continuous heating panel 8 should have a value of at least 25%, but preferably approximately 30%. In an alternative view of this criterion of the embodiment it can also be provided that the enthalpy of the flow medium W flowing into the continuous heating panel 8 should, in the case of the said operating conditions, at least have a value of H=1750 kJ/kg. The further continuous heating panel 10 provided for the adherence of these conditions according to the embodiment, is adapted to these boundary conditions with regard to its dimensioning, therefore, for example, with regard to the nature, number and embodiment of the pipes of the steam generator 30 forming it, with due consideration of the heat evolved present according to the embodiment in the area provided for its spatial positioning within the heating gas channel 6 .
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The invention relates to a steam generator in which the continuous heating panel of an evaporator is arranged in a heating gas channel which can be cross-flown in a more or less horizontal direction of a heating gas. Said continuous heating panel of the evaporator comprises a plurality of pipes of a steam generator which are connected in parallel to each other. Said pipes are constructed in such a way that they cross a flow medium and are provided with the part of a more or less vertical down pipe which can be cross-flown by the flow medium in a downward direction and with the part of a rising pipe connected downstream with respect to the down pipe on the side of the flow medium and which is more or less vertical and can be cross-flown by the flow medium in an upward direction. The continuous heating panel of the evaporator is arranged in such a way that one pipe of the steam generator which is hotter than the other pipe of the steam generator of the same continuous heating panel of the evaporator has a flow medium rate which is higher than that of the other pipe of the steam generator. The aim of said invention is to operate said steam generator in a relatively simple manner in association with a highly stable flow in the continuous heating panel of the evaporator. For this purpose, the flow medium of the continuous heating panel of the evaporator is supplied in such a way that the flow velocity thereof is higher than a minimum flow velocity predefined in the down pipe. The inventive steam generator is extremely well adapted for carrying out said method and comprises another continuous heating panel of the evaporator which is connected downstream with respect to the continuous heating panel of the evaporator on the side of the flow medium.
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CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims benefit and priority to U.S. Provisional patent application Ser. No. 60/668,651, filed Apr. 5, 2005. The entire contents of which are hereby incorporated by reference.
BACKGROUND
[0002] The invention includes embodiments that relate to a method for producing a cure system and for an adhesive system. The invention includes embodiments that relate to a method for producing an electronic device.
[0003] Semiconductor chips may be mounted to a substrate in an electronic device. The mounting may not be perfect and air-filled gaps may result between a surface of the chip and a surface of the mounting substrate. Because the air gaps may be undesirable, an underfill resin may be used to fill in the gaps. Underfill material may be used to improve reliability of the device. Further, the use of an underfill material may improve a fatigue life of solder bumps in an assembly.
[0004] To address shortcomings associated with traditional capillary underfill resins, a No-Flow Underfill (NFU) material was developed. No-Flow Underfill may include a curable resin, such as an epoxy resin, and may be unfilled, or filled with nano-size filler. The resin filler may be functionalized colloidal silica. The higher the filler content in the resin, the closer may be a match of the coefficient of thermal expansion (CTE) of the cured resin relative to a semiconductor chip. Unfortunately, for reasons of processability and the like, filler loadings of more than about 50 weight percent in the uncured resin may be problematic. To exacerbate the situation, after the addition of a curing agent, the final filler loading may be below 30 weight percent of the total composition. A typical CTE of a cured no-flow underfill epoxy resin with filler loading below 30 weight percent may be above 50 ppm/° C.
[0005] It may be desirable to have an underfill material having one or more of a coefficient of thermal expansion of less than 50 ppm/° C., a filler loading of greater than 30 weight percent, an acceptable level of processability, transparency, or a desirably high glass transition temperature (Tg). It may be desirable to have a process for making and/or using an underfill material system having improved or different properties than are currently available. It may be desirable to have an apparatus or article employing a no-flow underfill material system having improved or different properties than are currently available.
BRIEF DESCRIPTION
[0006] An embodiment of the invention may provide a method of producing a cure system. The method may include mixing a curing agent that is a low temperature liquid and a finely divided refractory solid. The refractory solid may be non-reactive with the curing agent.
[0007] An embodiment of the invention may provide a method, including dispersing a compatibilized and passivated refractory solid into a mixture or solution of a low temperature liquid curing agent and a low boiling solvent, and removing the solvent from the mixture or solution to form a solvent-free liquid dispersion of curing agent and refractory solid. The solvent may be free of hydroxyl-groups and the curing agent may not react with the solid.
[0008] In one aspect, the method may further include mixing the dispersion with a curable resin to form an adhesive system. In another aspect, the method may further include applying a portion of the adhesive system to a substrate and contacting the portion with an electronic component. The adhesive system may be cured to secure the chip to the substrate.
[0009] In one embodiment, the invention may provide a system, including means for securing a chip to a substrate, means for curing the securing means; and means for matching the coefficient of thermal expansion of the securing means to one or both of the chip or substrate. The matching means may be dispersed in the curing means.
DETAILED DESCRIPTION
[0010] The invention includes embodiments that relate to a cure system comprising a compatiblized and passivated refectory solid and a hardener or a curing agent (collectively “curing agent”). The curing agent may be liquid or fluid at a low temperature. The invention includes embodiments that relate to methods of making and/or using the cure system. In one embodiment, an adhesive system includes the cure system in combination with a curable resin. Other embodiments relate to electronic devices made using the adhesive system.
[0011] As used herein, cured refers to a curable composition having reactive groups in which more than half of the reactive groups have reacted or cross linked; curing agent refers to a material that may interact with a curable resin to crosslink monomers in a resin system, such as an epoxy resin. Approximating language, as used herein throughout the specification and claims, may be applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term or terms, such as “about”, may not to be limited to the precise value specified. In at least some instances, the approximating language may correspond to the precision of an instrument for measuring the value.
[0012] Hydroxyl-free, hydroxyl-group free, solvent-free, no-flow, and the like include a complete absence of the indicated material or property, and further include a substantial absence of the indicated material. That is, the “no-” and “-free” modifiers, and the like, are not used in a strict or absolute sense and may contain insignificant, trace, residual or minimal amounts of the indicated material or property unless context or language indicates otherwise. Derivatives may include conjugate acids or salts. Stability, as used herein in the specification and claims, refers to the lack of reaction, or the lack thereof, of active termination sites on the surface of the refractory solid and the curing agent over a period of time, e.g., one week, two weeks, and the like. The term “functionalized” may refer to a material in which functional groups have been manipulated or affected in some manner, such as reacted with a compatibilizing material or a passivating material.
[0013] In one embodiment, a room temperature liquid cure system may include a compatiblized and passivated refectory solid and a liquid curing agent. The cure system may be combined with a curable resin to initiate cure of the resin, that is, to crosslink reactive monomers contained in the resin. Particularly, the compatiblized and passivated refectory solid may be homogeneously dispersed into a low temperature liquid curing agent as filler to form the cure system. In one embodiment, the cure system may be combined with a curable resin to form an adhesive system. The adhesive system may cure quickly after combining, may have a pot life that extends for hours or days, or may have an indefinite pot life or desirable shelf life until a further triggering event occurs, such as the application of energy to the adhesive system. Such energy may include thermal energy, e-beam energy, UV light, and the like.
[0014] Suitable compatiblized and passivated refectory solid may include a plurality of particles of one or more metal, metalloid, ceramic, or organic material. Refractory may include materials with a high melting temperature, such as melting temperatures in a range of greater than about 1000 degrees Celsius. In one embodiment, the solid may include aluminum, antimony, arsenic, beryllium, boron, carbon, chromium, copper, gallium, gold, germanium, indium, iron, hafnium, magnesium, manganese, molybdenum, phosphorous, silicon, silver, titanium, tungsten, or zirconium, or the like, or an alloy of two or more thereof. In one embodiment, the solid may include one or more of arsenic, aluminum, boron, gallium, germanium, silicon, titanium, or an oxide or nitride thereof, such as alumina, silica, titania, boron nitride, and the like. For ease of reference, silica may be used as a non-limiting example of a suitable solide. Silica may include colloidal silica (CS), fused silica, or fumed silica, and the like.
[0015] Prior to compatibilizing and passivating, a suitable solid oxide may have an active surface termination site that comprises a silanol or hydroxyl group. A suitable solid nitride may have the active surface termination site include an amide or an imide. Subesquent to compatibilizing and passivating, the density of active termination sites may be controlled to be in a predetermined range. For example, with colloidal nano-particle silica the active termination site density may be about 5 active sites per square nanometer (OH/nm 2 ) or less, about 4.75 OH/nm 2 or less, or in a range of from about 50H/nm 2 to about 10H/nm 2 , from about 50H/nm 2 to about 3 OH/nm 2 , or from about 4.5 OH/nm 2 to about 4.0 OH/nm 2 . Because the active termination site density may correspond to shelf life or stability, a suitable stability ratio (the ratio of viscosity (two weeks/initial)), may be less than about 5, less than about 4, less than about 3 less than about 2, or about 1.
[0016] As noted hereinabove, compatibilizing and passivating or capping active termination sites may be accomplished by, for example, a sequential treatment. A first portion of active surface termination sites may be reacted with a compatiblizing composition. A suitable compatiblizing composition may include those disclosed hereinabove, such as an alkoxysilane having an organic moiety that may be one or more of acrylate, alkyl, phenyl, cyclohexyloxy, or glycidyl. Of the remaining active termination sites, a second portion may be reacted with a passivating composition, such as a silazane or other capping agent as disclosed herein.
[0017] A suitable water dispersion of colloidal silica for use as a precursor to compatiblized and passivated colloidal silica may be commercially obtained from, for example, Nissan Chemical America Corporation (Houston, Tex.) under the tradename SNOWTEX, or NALCO 1034A, which is available from Nalco Chemical Company (Napier, Ill.). SNOWTEX 40 has an average particle size in a range of from about 10 nanometers to about 30 nanometers.
[0018] The refectory solid initially may be hydrophilic or somewhat incompatible with an organic or non-polar phase due to the presence of active termination sites on the particle surface. For example, colloidal silica may be hydrophilic due to the presence of silanol groups at the surface. The hydrophilicity may make dispersion in an organic phase problematic or impracticable. Compatiblizing the solid surface may create an organophilic coating on the surface of the solid particles to make the particles dispersible in, or compatible with, an organic phase or a non-polar liquid. Compatiblizing may be accomplished with, for example, a trialkoxy organosilanes (e.g., phenyl trimethoxy silane, glycidoxy propyl trimethoxy silane, and the like). To reduce further the content or density of active termination sites on the surface, the compatiblized refectory solid may be post treated or reacted with a capping agent or a passivating agent. The reaction with the capping agent may form particles with a relatively low content of available hydroxyl or silanol groups. As disclosed above, such functional groups may be referred to as active termination sites.
[0019] A compatibilized refectory solid may be further treated or capped with one or more capping agent for passivation. Suitable capping agents may include one or more of a triorganosilane, an organodisilazane, organoalkoxysilane, or an organohalosilane such as organochlorosilane. In one embodiment, the capping agent may include one or more of hexamethyl disilazane (HMDZ), tetramethyl disilazane, divinyl tetramethyl disilazane, diphenyl tetramethyl disilazane, N-(trimethyl silyl) diethylamine, 1-(trimethyl silyl) imidazole, trimethyl chlorosilane, pentamethyl chloro disiloxane, trimethylmethoxysilane and pentamethyl disiloxane, and the like.
[0020] An acid, a base, or a condensation catalyst may be used to promote condensation of, for example, silanol groups on a silica particle surface and an alkoxy silane group to compatiblize the silica particle. Suitable condensation catalysts may include organo-titanate and organo-tin compounds such as tetrabutyl titanate, titanium isopropoxy bis (acetyl acetonate), dibutyltin dilaurate, and the like, or combinations of two or more thereof.
[0021] The compatiblized and passivated (e.g., capped) particles may have a relatively reduced number and/or density of active termination sites on the particle surface. The reduced number or reduced density may provide a stable dispersion of particles in a curing agent, a curable resin, or a mixture of both curing agent and curable resin. Further, reduced density of active termination sites (e.g., hydroxyl content on compatiblized and passivated silica) may reduce or eliminate reactions with an anhydride, which may otherwise react with, for example, available hydroxyl groups. Such anhydride/hydroxyl reactions may form a free acid. Thus, reducing or eliminating active termination sites, such as by passivation, may reduce or eliminate free acid formation and may increase stability.
[0022] The amount of refectory solid present in a cure system may be expressed as a weight percent of the total weight. The refectory solid may be present in a cure system in an amount greater than about 0.5 weight percent, or in a range of from about 0.5 weight percent to about 80 weight percent. In one embodiment, the refectory solid content may be present in a cure system in an amount in a range of from about 1 weight percent to about 5 weight percent, from about 5 weight percent to about 10 weight percent, from about 10 weight percent to about 20 weight percent, from about 20 weight percent to about 30 weight percent, from about 30 weight percent to about 40 weight percent, from about 40 weight percent to about 50 weight percent, from about 50 weight percent to about 60 weight percent, or greater than 60 weight percent.
[0023] Suitable refractory solids may have a surface area greater than about 20 square meters per gram, greater than about 60 square meters per gram, or greater than about 150 square meters per gram. The solid may include a plurality of nano-particles having an average diameter in a range of from about 1 nanometer to about 100 nanometers. In one embodiment, the refractory solids may have an average particle size of less than about 1 micrometer to about 500 nanometers, from about 500 nanometers to about 250 nanometers, from about 250 nanometers to about 100 nanometers, from about 100 nanometers to about 50 nanometers, from about 50 nanometers to about 25 nanometers, from about 25 nanometers to about 10 nanometers, from about 10 nanometers to about 5 nanometer, or less than about 5 nanometer.
[0024] Suitable particles may have one or more of a spherical, amorphous or geometric morphology. In one embodiment, the particles may be amorphous. Suitable particles may be porous, may be non-porous, or may include some porous and some non-porous particles. The pores may be uniform in shape or size, or may be shaped and/or sized differently from each other.
[0025] A suitable low temperature liquid curing agent may include an anhydride, such as carboxylic acid anhydride, with a relatively low melt point (below about 100 degrees Celsius) or that may be liquid at about room temperature. Low temperature may include temperatures in a range of less than about 100 degrees Celsius, and particularly may include temperatures in a range of less than about 50 degrees Celsius. In one embodiment, the curing agent is a flowable liquid in a temperature range of from about 25 degrees Celsius to about 35 degrees Celsius.
[0026] Liquid refers to a property of being fluid or able to flow or thermoplastically deform. A measure of fluidity may be expressed as viscosity, which is the degree to which a fluid may resist flow under an applied force, as measured by the tangential friction force per unit area divided by the velocity gradient under conditions of streamline flow. In one embodiment, the cure system at low temperature may have a Brookfield viscosity of less than about 1000 Poise, in a range of from 1000 Poise about to about 100 Poise, from about 100 Poise to about 1000 centipoise, from about 1000 centipoise, or less than about 1000 centipoise. Viscosity may be measured according to ASTM D-2393-67, which is incorporated herein by reference. The viscosity may differ from embodiment to embodiment, for example, in response to changes in filler loading or type, temperature, and selection of curing agent.
[0027] Suitable liquid or low melting temperature anhydrides may include one or more aromatic anhydride, aliphatic anhydride, or cycloaliphatic anhydride. The curing agent may include one or more carboxylic acid anhydrides, which may be selected from aromatic carboxylic acid anhydride, aliphatic carboxylic acid anhydride, or cycloaliphatic carboxylic acid anhydride. Carboxylic anhydrides may be prepared by reacting a carboxylic acid with an acyl halide, or by dehydrating a carboxylic acid, that is, eliminate water between two carboxylic acid molecules to form the anhydride. Alternatively, carboxylic acid anhydrides may be obtained commercially from common chemical suppliers.
[0028] Aromatic anhydrides may include one or more of benzoic anhydride; phthalic anhydride; 4-nitrophthalic anhydride; naphthalene tetracarboxylic acid dianhydride; naphthalic anhydride; tetrahydro phthalic anhydride; derivatives thereof; and the like. In one embodiment, a curing agent may include one or more aromatic carboxylic acid anhydrides. Cycloaliphatic anhydrides may include one or more of cyclohexane dicarboxylic anhydride, hexahydro phthalic anhydride, methyl-hexahydro phthalic anhydride (MHHPA), derivatives thereof, and the like. In one embodiment, a curing agent may include 5,5′-(1,1,3,3,5,-hexamethyl-1,5-trisiloxane diyl) bis [hexahydro 4,7-methanoisobenzofuran-1,3-dione] (TriSNBA), which is commercially available from GE Silicones (Waterford, N.Y.).
[0029] In one embodiment, a curing agent may include one or more of butanoic anhydride; dodecenyl succinic anhydride; 2,2-dimethyl glutaric anhydride; ethanoic anhydride; glutaric anhydride; hexafluoro glutaric acid anhydride; itaconic anhydride; tetrapropenylsuccinic anhydride; maleic anhydride; 2-methyl glutaric anhydride; 2-methyl propionic anhydride 1,2-cyclohexane dicarboxylic anhydride; octadecyl succinic anhydride; 2-or n-octenyl succinic anhydride; 2-phenylglutaric anhydride; propionic acid anhydride; 3,3-tetramethylene glutaric anhydride; derivatives thereof; and the like.
[0030] Structures of some other suitable anhydrides are shown below.
[0031] The cure system may be blended, dispersed and/or mixed into a curable resin to form an adhesive system. In one embodiment, the resin may have a filler pre-dispersed therein. That is, prior to mixing both the cure system and the resin system each have a high content of refractory solids dispersed therein.
[0032] Suitable resins may include one or more aliphatic epoxy resins, cycloaliphatic epoxy resins, or aromatic epoxy resins. Suitable aliphatic epoxy resins may include one or more of butadiene dioxide, dimethyl pentane dioxide, diglycidyl ether, 1,4-butanediol diglycidyl ether, diethylene glycol diglycidyl ether, and dipentene dioxide, and the like. Suitable aliphatic epoxy monomers may include one or more of butadiene dioxide, dimethylpentane dioxide, diglycidyl ether, 1,4-butanediol diglycidyl ether, diethylene glycol diglycidyl ether, or dipentene dioxide, and the like. In one embodiment, the aliphatic dioxirane monomer may include CYRACURE UVR 6105, which is commercially available from Dow Chemical (Midland, Mich.).
[0033] Suitable cycloaliphatic epoxy resins may include one or more of 3-cyclohexenyl methyl-3-cyclohexenyl carboxylate diepoxide; 2-(3,4-epoxy) cyclohexyl-5,5-(3,4-epoxy) cyclohexane-m-dioxane; 3,4-epoxy cyclohexyl alkyl-3,4-epoxy cyclohexane carboxylate; 3,4-epoxy-6-methyl cyclohexyl methyl-3,4-epoxy-6-methyl cyclo hexane carboxylate; vinyl cyclohexane dioxide; bis (3,4-epoxy cyclohexyl methyl) adipate; bis (3,4-epoxy-6-methyl cyclohexyl methyl) adipate; bis (2,3-epoxy cyclopentyl) ether; 2,2-bis (4-(2,3-epoxy propoxy) cyclohexyl) propane; 2,6-bis (2,3-epoxy propoxy cyclohexyl-p-dioxane); 2,6-bis (2,3-epoxy propoxy) norbornene; diglycidyl ether of linoleic acid dimer; limonene dioxide; 2,2-bis (3,4-epoxy cyclohexyl) propane; dicyclopentadiene dioxide; 1,2-epoxy-6-(2,3-epoxy propoxy) hexahydro 4,7-methanoindane; p-(2,3-epoxy) cyclopentyl phenyl-2,3-epoxypropyl ether; 1-(2,3-epoxy propoxy) phenyl-5,6-epoxy hexahydro-4,7-methanoindane; (2,3-epoxy) cyclopentyl phenyl-2,3-epoxy propyl ether); 1,2-bis (5-(1,2-epoxy) 4,7-hexahydro methano indanoxyl) ethane; cyclopentenyl phenyl glycidyl ether; cyclohexane diol diglycidyl ether; diglycidyl hexahydrophthalate; and 3-cyclohexenyl methyl-3-cyclohexenyl carboxylate diepoxide; and the like. In one embodiment, a cycloaliphatic epoxy monomer may include one or more 3-cyclohexenyl methyl-3-cyclohexenyl carboxylate diepoxide, 3-(1,2-epoxy ethyl)-7-oxabicycloheptane; hexanedioic acid, bis (7-oxabicyclo heptyl methyl) ester; 2-(7-oxabicyclohept-3-yl)-spiro-(1,3-dioxa-5,3′-(7)-oxabicyclo heptane; and methyl 3,4-epoxy cyclohexane carboxylate, and the like.
[0034] Suitable aromatic epoxy resins may include one or more of bisphenol-A epoxy resins, bisphenol-F epoxy resins, phenol novolac epoxy resins, cresol-novolac epoxy resins, biphenol epoxy resins, biphenyl epoxy resins, 4,4′-biphenyl epoxy resins, polyfunctional epoxy resins, divinylbenzene dioxide, resorcinol diglyciyl ether, and 2-glycidyl phenyl glycidyl ether. Other suitable resins may include silicone-epoxy resins and siloxane epoxy resins. Bisphenol-F resins may be commerically available from Resolution Performance Products (Pueblo, Colo.).
[0035] Optional additives may be incorporated into the resin portion of the system, the curing agent portion of the system, or both. Suitable additives may include one or more catalyst, accelerator, flexibilizer, carbinol, organic diluent, suspension agent, fire retardant, pigment, thermally conductive filler, electrically conductive filler, thermally insulative filler, electrically insulative filler, and the like.
[0036] A suitable catalyst or accelerator may initiate a crosslinking process, accelerate cure rate, or decrease cure time or temperature of an adhesive system. A catalyst or accelerator may be present in an amount less than about 10 parts per million (ppm), in a range of from about 10 ppm to about 100 ppm, from about 100 ppm to about 0.1 weight percent, from about 0.1 weight percent to about 1 weight percent, or greater than about 1 weight percent of the total formulation weight.
[0037] A suitable catalyst or an accelerator may include, but is not limited to, an onium catalyst or a free-radical generating compound. Suitable onium catalysts may include bisaryliodonium salts (e.g. bis (dodecyl phenyl) iodonium hexafluoro antimonate, (octyl oxyphenyl phenyl) iodonium hexafluoro antimonate, bisaryl iodonium tetrakis (penta fluorophenyl) borate), triaryl sulphonium salts, and combinations of two or more thereof. Suitable free-radical generating compounds may include one or more aromatic pinacols, benzoinalkyl ethers, organic peroxides, and the like. The presence of a free radical generating compound may enable decomposition of an onium salt at a relatively lower temperature.
[0038] In one embodiment, a catalyst or an accelerator may be added to an epoxy-based adhesive system. Useful catalysts or accelerators may include one or more amine; alkyl-substituted imidazole; imidazolium salt; phosphine; metal salt, such as aluminum acetyl acetonate (Al(AcAc) 3 ); salt of nitrogen-containing compound; and the like. The nitrogen-containing compound may include, for example, one or more amine compounds, di-aza compounds, tri-aza compounds, polyamine compounds and the like. A salt of a nitrogen-containing compound may include, for example 1,8-diazabicyclo (5,4,0)-7-undecane. The salt of the nitrogen-containing compounds may be obtained commercially, for example, as POLYCAT SA-1 or POLYCAT SA-102. POLYCAT SA-1 is a delayed-action, heat-activated catalyst based on the cyclic amine, 1,8 diaza-bicyclo (5,4,0) undec-ene-7. POLYCAT SA-1 contains DBU catalyst and an organic acid “blocker”. POLYCAT is a trademark of Air Products and Chemicals, Inc (Allentown, Pa.). Other suitable catalysts may include triphenyl phosphine (TPP), N-methylimidazole (NMI), and/or dibutyl tin dilaurate (DiButSn).
[0039] Additives, such as flexibilizers, may include one or more organic compounds having a hydroxyl-containing moiety. Suitable flexibilizers may include one or more of polyol or bisphenol. The polyol may be straight chain, branched, cycloaliphatic, or aromatic and may contain from about 2 to about 100 carbon atoms. Examples of such polyfunctional alcohols may include one or more of ethylene glycol; propylene glycol; 2,2-dimethyl-1,3-propane diol; 2-ethyl, 2-methyl, 1,3-propane diol; 1,3-pentane diol; 1,5-pentane diol; dipropylene glycol; 2-methyl-1,5-pentane diol; 1,6-hexane diol; dimethanol decalin, dimethanol bicyclo octane; 1,4-cyclohexane dimethanol; triethylene glycol; and 1,10-decane diol. In one embodiment, an alcohol may include 3-ethyl-3-hydroxymethyl oxetane (commercially available as UVR6000 from Dow Chemicals (Midland, Mich.)).
[0040] Suitable bisphenols may include one or more dihydroxy-substituted aromatic hydrocarbon. In one embodiment, a dihydroxy-substituted aromatic compound may include one or more of 4,4′-(3,3,5-trimethyl cyclohexylidene)-diphenol; 2,2-bis (4-hydroxyphenyl) propane (bisphenol A); 2,2-bis (4-hydroxyphenyl) methane (bisphenol F); 2,2-bis (4-hydroxyl-3,5-dimethylphenyl) propane; 2,4′-dihydroxy diphenylmethane; bis (2-hydroxyphenyl) methane; bis (4-hydroxyphenyl) methane; bis (4-hydroxyl-5-nitrophenyl) methane; bis (4-hydroxyl-2,6-dimethyl-3-methoxyphenyl) methane; 1,1-bis (4-hydroxyphenyl) ethane; 1,1-bis (4-hydroxyl-2-chlorophenyl ethane; 2,2-bis (3-phenyl-4-hydroxyphenyl) propane; bis (4-hydroxyphenyl) cyclohexyl methane; 2,2-bis (4-hydroxyphenyl)-1-phenylpropane; 2,2,2′,2′-tetrahydro-3,3,3′,3′-tetramethyl,1′-spirobi {1H-indene}-6,6′-diol (SBI); 2,2-bis (4-hydroxyl-3-methylphenyl) propane (DMBPC); and C1-C13 alkyl-substituted resorcinols, and the like.
[0041] A suitable organic diluent may be added to an adhesive system according to embodiments of the invention. The organic diluent may decrease a viscosity of the adhesive system. Suitable reactive diluents may include, but are not limited to, dodecylglycidyl ether, 4-vinyl-1-cyclohexane diepoxide, and di (beta-(3,4-epoxy cyclohexyl) ethyl) tetramethyl disiloxane, or combinations of two or more thereof. Other diluents may include monofunctional epoxies and/or compounds containing at least one epoxy functionality. Such diluents may include, but are not limited to, alkyl derivatives of phenol glycidyl ethers such as 3-(2-nonylphenyloxy)-1,2-epoxy propane or 3-(4-nonylphenyloxy) 1,2-epoxy propane; glycidyl ethers of phenol; substituted phenols such as 2-methylphenol, 4-methyl phenol, 3-methylphenol, 2-butylphenol, 4-butylphenol, 3-octylphenol, 4-octylphenol, 4-t-butylphenol, 4-phenylphenol, and 4-(phenyl isopropylidene) phenol; and the like. In one embodiment, the reactive diluent may include 3-ethyl-3-hydroxymethyl-oxetane, which is commercially available as UVR6000 from Dow Chemical (Midland, Mich.).
[0042] A suitable flame retardant may include one or more material that contains phosphorus, iron, halogen, oxide, or hydroxide. In one embodiment, a flame retardant additive may include phosphoramide, triphenyl phosphate (TPP), resorcinol diphosphate (RDP), bisphenol A disphosphate (BPA-DP), organic phosphine oxide, halogenated resin (e.g., tetrabromobisphenol A), metal oxide (e.g. bismuth oxide), metal hydroxide (e.g., MgOH), and combinations of two or more thereof. Suitable pigment may include one or both of reactive and non-reactive materials.
[0043] In one embodiment, a cure system may be produced by dispersion of refractory solids (e.g. CS) into a liquid curing agent and a solvent to form a solution. A suitable solvent may include a hydroxyl-group free solvent, such as propylene glycol methyl ether acetate, toluene, xylene, supercritical fluid (e.g., SCF CO 2 ), and the like.
[0044] After the dispersion or mixing, the solvent may be removed. Suitable solvent removal methods may include affecting the temperature and/or pressure to volatilize the solvent. That is, heat, vacuum, or both may be used to extract or remove the solvent from the dispersion. If a supercritical fluid, such as supercritical carbon dioxide, is used, room temperature and pressure may be sufficient to remove the solvent. Subsequently, a solvent-free filled low temperature liquid cure system according to an embodiment of the invention may be recovered and stored.
[0045] In one embodiment, a cure system further may be mixed with a curable resin to form an adhesive system. The resulting adhesive system may have a flowable or workable viscosity for a predetermined time, i.e., pot life. For a no-flow underfill application, the viscosity may be such to allow flow of the underfill during dispensing on the substrate and formation of solder electrical connection during a reflow process. Viscosity selection may be made by one or more of determining amounts of refractory solids in the resin, amounts of refractory solids in the cure system, the initial unfilled viscosity of the resin and/or cure system, temperature, the presence or amount of additives or flow-modifiers, control over working pressure, use of sonic vibrations, and the like.
[0046] The adhesive system according to embodiments of the invention may be used in an electronic device. In one embodiment, the adhesive system may be used as an underfill material, such as a no-flow underfill, in a flip chip assembly to secure a chip to a substrate. The adhesive system may exhibit one or more of: prolonged room temperature stability, desirable solder ball fluxing, and a coefficient of thermal expansion below about 50 ppm/° C. when cured and used as, for example, an encapsulant or an underfill. In one embodiment, a cured adhesive system may have properties that include one or more of a low CTE (below about 40 ppm/° C.), self-fluxing properties during application, a high Tg (above about 100 degrees Celsius), a high heat deflection temperature (HDT), and relatively high optical transparency.
[0047] An embodiment of the invention may provide a no-flow underfill material having a coefficient of thermal expansion, when cured, of less than 50 ppm/° C., in a range of from about 50 ppm/° C. to about 40 ppm/° C., from about 40 ppm/° C. to about 30 ppm/° C., or less than about 30 ppm/° C. An embodiment may enable a final filler loading of greater than 30 weight percent, a range of from about 30 weight percent to about 40 weight percent, from about 40 weight percent to about 50 weight percent, or greater than about 50 weight percent, while maintaining one or more of an acceptable level of processability, transparency, or a desirably high glass transition temperature (Tg). Processability relates to properties that may include flowability, viscosity, visco-elasticity, tack, wetability, out-gassing, percent void, shelf life, cure time, cure temperature, and the like. Transparency relates to the property of permitting the relatively free passage of electromagnetic radiation through a pre-determined thickness of material without one or more refraction, reflection or absorption. Glass transition temperature relates to an inflection point on a plot of modulus versus temperature. The Tg indicates a temperature range above which a material may undergo plastic deformation, or may change from a rigid or brittle state to a rubbery or softened state.
[0048] In one embodiment, an adhesive system may be a no-flow underfill, a capillary flow underfill, a wafer level underfill, a thermal interface material (TIM), and/or pre-applied and optionally B-staged on a substrate, and may be dispensable and have utility in the fabrication of an electronic device, such as a computer, an optical device, or a semiconductor assembly. As an underfill material or encapsulant, the adhesive system may reinforce physical, mechanical, and electrical properties of solder bumps that may secure a chip to a substrate, and/or may act as flux during solder bump melting.
[0049] No-flow underfilling may include dispensing an underfill encapsulant material on the substrate or semiconductor device and performing solder bump reflowing simultaneously with underfill encapsulant curing. Wafer level underfilling may include dispensing underfill materials onto the wafer before dicing into individual chips that are subsequently mounted in the final structure via flip-chip type operations. Alternatively to no-flow underfill, dispensing the underfill material may include applying in a fillet or bead extending along at least one edge of a chip, and allowing the underfill material to flow by capillary action under the chip to fill all, or nearly all, gaps between the chip and the substrate.
[0050] In one embodiment, an adhesive according to embodiments of the invention may be energy cured, such as by heat, UV light, microwave energy, electron been energy, and the like. For heat or thermal curing, a suitable temperature may be in a range of from about 50 degrees Celsius to about 100 degrees Celsius, from about 100 degrees Celsius to about 200 degrees Celsius, from about 200 degrees Celsius to about 250 degrees Celsius, or greater than about 250 degrees Celsius. For no flow underfill, the cure temperature is in a range of from about 183 degrees Celsius (melting point of eutectic solder) to about 230 degrees Celsius for Sn/Pb eutectic solder and from about 230 degrees Celsius to about 260 degrees Celsius for lead-free solder. Curing may occur over a period of less than about 30 seconds, in a range between about 30 seconds and about 1 minute, from about 1 minute to about 5 minutes, from about 5 minutes to about 30 minutes, from about 30 minutes to about 1 hour, from about 1 hour to about 5 hours, or greater than about 5 hours. For no flow underfill a cure process (during a reflow) may be in a range of from about 3 minutes to about 10 minutes.
[0051] Optional post-curing may be performed at a temperature of less than 100 degrees Celsius, in a range of from about 100 degrees Celsius to about 150 degrees Celsius, or greater than about 150 degrees Celsius, over a period of less than one hour, in a range of from about 1 hour to about 4 hours, or greater than about 4 hours. For no-flow underfill, the post cure may be at a temperature in a range of from about 100 degrees Celsius to about 160 degrees Celsius over a period of from about 1 to about 4 hours. Other times, temperatures and pressures for curing and post-curing may be selected with reference to application specific parameters.
[0052] In one embodiment, a cure system according to an embodiment of the invention may consist essentially of a liquid curing agent and compatiblized and passivated silica. In another embodiment, a cure system may consist essentially of a liquid carboxylic acid anhydride curing agent, and compatiblized colloidal silica treated with a capping agent. In yet another embodiment, a cure system may consist essentially of a room temperature liquid anhydride-curing agent, and compatiblized and passivated colloidal silica having a nano-size average particle diameter.
EXAMPLES
[0053] The following examples are intended only to illustrate methods and embodiments in accordance with the invention, and as such should not be construed as imposing limitations upon the claims. Unless specified otherwise, all ingredients are commercially available from such common chemical suppliers as Alpha Aesar, Inc. (Ward Hill, Mass.), Sigma-Aldrich Corp. (St. Louis, Mo.), and the like.
Example 1
Preparation of Compatiblized and Passivated Solids
[0054] A mixture is made by adding 300 grams of SNOWTEX-ZL (80 nm average particle size) to 300 grams of isopropyl alcohol (IPA). After thoroughly mixing, 2 grams of phenyl trimethoxysilane (Ph(OMe) 3 Si) is added to the mixture. The resulting mixture is refluxed for three hours. After reflux, the mixture is cooled to room temperature. The cooled mixture has 600 grams of methoxypropanol added while mixing, until thoroughly mixed. A stripping process removes 600 grams of volatile material, by weight. Hexamethyl disilazane (HMDZ) is added to the stripped mixture in an amount of 6 grams. The mixture is thoroughly mixed, refluxed for 1 hour at elevated temperature, and then stripped to 200 grams total weight. 300 grams of propylene glycol methyl ether acetate or 1-methoxy-2-acetoxypropane (PGMEA) is added and mixed thoroughly. The resulting mixture is stripped of 300 grams of volatile weight and filtered. The yield is 250 grams of compatiblized and passivated colloidal silica material having solids of 29.10 weight percent. The recovered sample is labeled Sample 1A. An ingredient list is shown in Table 1, below. The above disclosed process is repeated to form Sample 1B, the difference being that silica having an average particle size of 50 nm, rather than 80 nm, is used.
TABLE 1 Ingredient list for compatiblized and passivated solids (Sample 1A) INGREDIENT AMOUNT (g) Snowtex-ZL 300 Snowtex-ZL 80 nm particles, Conc. OH = 5/nm 2 IPA 300 Ph(OMe) 3 Si 2 Methoxypropanol 600 HMDZ 6 PGMEA 300 Yield 215 Solids 29.10% Appearance white liquid
Example 2 through Example 4
Preparation of Cure System Including Compatiblized and Passivated Solids
[0055] The compatiblized and passivated colloidal silica materials produced in Example 1 (Samples 1A and 1B) are added to liquid anhydride materials methylhexahydrophthalic anhydride (MHHPA) and 5,5′-(1,1,3,3,5,-hexamethyl-1,5-trisiloxane diyl) bis [hexahydro-4,7-methanoisobenzofuran-1,3-dione] (TriSNBA) to form Samples 2-4. Samples 2-4 were evaporated using a commercially available rotary evaporator at 70 degrees Celsius. Rotary evaporators may be obtained from, for example, Thomas Industries, Inc. (Skokie, Ill.). An ingredient list for the cure systems containing compatiblized and passivated silica is shown in Table 2. A list of properties for the Samples 2-4 shown in Table 2 is shown is Table 3. The viscosity measurements are performed with SP # 40 at 10 rpm, and the results are in centipoise, unless otherwise indicated.
TABLE 2 Ingredient list for cure systems containing Samples 1A and 1B). Sample 2 Sample 3 Sample 4 Sample 1A 35 35 — (80 nm ave size) Sample 1B — — 37.3 (50 nm ave size) MHHPA 10 — 10 TrisNBA/MHHPA — 10 — (40/60 ratio)
[0056]
TABLE 3
Properties for cure systems (Samples 2-3)
that contain Samples 1A and 1B.
Sample 2
Sample 3
Sample 4
Appearance
yellow
yellow
light yellow
Mass
20.15
20.06
20.1
% solids
50
50
50
Viscosity (centipoise)
600
3040
920
Example 5 and Example 6
Preparation of Adhesive Systems that Include a Cure System
[0057] An aliphatic dioxirane monomer, CYRACURE UVR 6105 is blended with Bisphenol F epoxy resin in a 75/25 ratio to form a base resin. A reactive diluent, UVR6000, is added to the base resin to form a mixture. A cure catalyst, POLYCAT SA-1, is added to the mixture of base resin and diluent to form a catalyzed mixture. The catalyzed mixture is blended with 60 weight percent of a cure system (Samples 2 or 3) at room temperature for approximately 10 minutes to form an adhesive system (Samples 5 and 6, respectively). After which, each adhesive system (Samples 5 and 6) is degassed at relatively high vacuum at room temperature for 20 minutes. Samples 5 and 6 are stored at negative 40 degrees Celsius.
[0058] For test and evaluation, Samples 5 and 6 are applied to a chip and to a substrate. The chip and substrate are set together to form an assembly. Thermal energy is applied to cure the adhesive systems, Samples 5 and 6. Test results are listed in Table 5. Viscosity is performed with spindle #40 at 20 rpm at room temperature, the results are in centipoise.
TABLE 4 Ingredient list for adhesive systems (Sample 5 and Sample 6) that each include a curable resin and a cure system. INGREDIENT Sample 5 Sample 6 Base Resin 1 5 5 Sample 2 4.07 — Sample 3 — 5 UV R6000 0.2 0.2 Polycat SA-1 0.0188 0.0216
[0059]
TABLE 5
Properties list for adhesive systems.
Test
Sample 5
Sample 6
Fluxing of eutectic solder
Good
Good
Viscosity (centipoise)
4880
29700
% solids
53%
52%
Tg TMA (° C.)
138.0
154.0
CTE-20-80 (ppm/° C.)
36.0
39.0
DSC peak (° C.)
214.4
208.1
DSC H onset (° C.)
164.4
154.7
DSC H (J/g)
199.0
168.8
DSC Tg (° C.)
123.5
147.0
[0060] The foregoing examples are merely illustrative, serving to illustrate only some of the features of the invention. The appended claims are intended to claim the invention as broadly as it has been conceived and the examples herein presented are illustrative of selected embodiments from a manifold of all possible embodiments. Accordingly it is Applicants' intention that the appended claims are not to be limited by the choice of examples utilized to illustrate features of the present invention. As used in the claims, the word “comprises” and its grammatical variants logically also subtend and include phrases of varying and differing extent such as for example, but not limited thereto, “consisting essentially of” and “consisting of.” Where necessary, ranges have been supplied, those ranges are inclusive of all sub-ranges there between. It is to be expected that variations in these ranges will suggest themselves to a practitioner having ordinary skill in the art and where not already dedicated to the public, those variations should where possible be construed to be covered by the appended claims. It is also anticipated that advances in science and technology will make equivalents and substitutions possible that are not now contemplated by reason of the imprecision of language and these variations should also be construed where possible to be covered by the appended claims.
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A cure system including a compatiblized and passivated refectory solid dispersed within a low temperature liquid curing agent is provided. An adhesive system including the cure system is provided, and an associated method. A device including the cured adhesive system is provided.
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FIELD OF THE INVENTION
The present invention relates agricultural combine harvesting machinery, and more particularly, to an apparatus and method for adjusting the combine cleaning shoe to offset the position of the shoe resulting from operating the combine on a slope.
BACKGROUND OF THE INVENTION
Combines are large self-propelled vehicles used for harvesting and threshing agricultural crop in a field. A combine operates by cutting or gathering crop standing in a field, and feeding the cut crop to a separator by means of a conveyor mechanism. In the separator, grain is threshed, or beaten from the husk, stems, pods, or cobs, and then the threshed grain is separated from crop material other than grain. After separating, some crop material other than grain is still mixed with the grain. A cleaning system is used to remove the crop material other than grain, sometimes called trash or chaff, from the grain. This is typically done in a device known as a cleaning shoe, which has mechanisms known as a chaffer and a sieve. Typically, the chaffer and sieve are large pans having a flat surface that are oscillated or vibrated to break up the crop material and separate out the grain. The chaffer and sieve can also be a series of adjacent planks that are oscillated or vibrated. The chaffer and sieve can be generally horizontally level from the front to back, or as is commonly seen, arranged to have an upward incline from front to back. In some cleaning systems, a fan is also used to blow the lighter chaff away from the heavier grain material in the chaffer and/or sieve.
In operation, the mixed grain and crop material is deposited onto the top front of the chaffer. The lighter weight chaff is separated from the grain by vibration and/or blowing, and the grain and small heavy particles of crop material other than grain fall through louvers in the floor of the chaffer onto the sieve, which is located beneath the chaffer. The sieve oscillates to separate out and break up crop material. The grain, which is heavier than the other crop material, falls through appropriate-size openings in the floor of the sieve, and the cleaned grain from the sieve is carried to the grain tank.
Because the cleaning shoe operates by shaking and/or blowing lighter material away from the heavier grain, cleaning shoes tend to work best on flat ground. When the combine is operated on a slope, the crop will tend to build up on the low side of the sieve and chaffer due to gravitational forces. This will result in inefficient cleaning action, with resultant grain loss.
While combines with pivoting wheel axles exist for use on land that is predominantly sloped, these hillside combine systems are complex and costly, and of a level of sophistication not needed for operation on generally flat ground or ground having only a mild degree of slope. Instead, one alternative solution for use with limited slope operation is for the level-land combines, as they are sometimes called, to utilize chaffers and sieves made from a plurality of adjacent longitudinal sections separated by dividers. When operating on a slope, material builds up against the dividers, which helps limit the crop build-up to just crop in that particular longitudinal section. However, these devices only reduce crop build-up on the downhill side of the combine, rather than completely eliminating the problem, resulting in cleaning that does not provide maximum grain yield, due to inefficient use of the cleaning shoe.
Additionally, some combines utilize systems in which the chaffer and/or sieve, or each longitudinal section thereof is pivotally mounted in a frame such that it can be pivoted or tilted relative to the frame to maintain the device level in relation to the slope of the combine and the ground. Such mechanisms are typically operated by means of an inclinometer and a motor to pivot the sections along their length with respect to the slope of the ground. Other mechanism utilize hanging weights tied into the pivots of the longitudinal sections to tilt the chaffer and/or sieve sections to horizontal and compensate for the slope of the combine. However, even with the use of systems that keep the chaffer or sieve sections horizontal relative to the ground slope, crop processing efficiency is decreased as compared to level-land processing, with efficiency losses depending on factors such as crop conditions and harvesting speed. Therefore, what is needed is a method and apparatus for crop harvesting on rolling or sloped ground that minimizes grain loss typically seen when harvesting on sloped ground, without having to reduce harvesting speed or utilize expensive mechanisms to achieve desired harvest yields.
SUMMARY OF THE INVENTION
The present invention, accordingly, provides a method limiting crop loss when harvesting on sloped or rolling ground having a limited slope by adjusting the chaffer and/or sieve, or longitudinal sections thereof, so as to overcompensate for the ground slope so that the chaffer and/or sieve sections are actually inclined away from horizontal opposite the direction of ground slope at a selected angle. Such overcompensation has been shown to produce increased crop harvesting efficiencies over systems that simply work to level the chaffer or sieve sections, without the high expenses associated with a hillside combine.
The present invention incorporates a system and apparatus for controlling a cleaning shoe having a chaffer and a sieve on a combine when the combine is operating on sloped ground comprising a detecting mechanism for detecting the angle of at least one of the chaffer or the sieve away from horizontal when the combine is operating on sloped ground, a control system for receiving the angle of operation from the detecting mechanism and calculating an angle of operation to improve grain harvesting efficiency, the angle being greater than the angle necessary to return the chaffer or sieve to a horizontal position, and a motor capable of rotating the chaffer or sieve about its longitudinal axis connected to at least one of the combine or sieve, the motor capable of receiving information from the control system to move the chaffer or sieve to the angle calculated by the control system.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic view illustrating a combine having a cleaning shoe in accordance with the present invention;
FIG. 2 is a perspective view of a cleaning shoe of the present invention;
FIG. 3 is schematic sectional view illustrating a sieve of the present invention when the combine is on a slope; and
FIG. 4 is a flow chart showing the steps of the method of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
In the discussion of the FIGURES the same reference numerals will be used throughout to refer to the same or similar components. In the interest of conciseness, various other components known to the art, such as harvesters, storage mechanisms and the like necessary for the operation of the invention, have not been shown or discussed, or are shown in block form.
In the following, numerous specific details are set forth to provide a thorough understanding of the present invention. However, it will be obvious to those skilled in the art that the present invention may be practiced without such specific details. In other instances, well-known elements have been illustrated in schematic or block diagram form in order not to obscure the present invention in unnecessary detail. Additionally, for the most part, details concerning computer software operation and the like have been omitted inasmuch as such details are not considered necessary to obtain a complete understanding of the present invention, and are considered to be within the knowledge of persons of ordinary skill in the relevant art.
FIG. 1 shows a combine 10 used for harvesting agricultural crops. The combine 10 comprises a supporting structure 12 having ground engaging wheels 14 extending from the supporting structure 12 . The operation of the combine 10 is controlled from the operator's cab 15 . A harvesting platform 16 is used for harvesting grain-bearing crop and directing it to a feeder house 18 . The cut crop is directed from the feeder house 18 to a separator mechanism 20 which threshes the grain from the crop material. Once the grain has been threshed and separated, some crop material other than grain is still mixed in with the grain and must be cleaned out, which is done in the cleaning shoe 100 .
The cleaning shoe 100 is located downstream from the separator mechanism 20 . The cleaning shoe 100 comprises a chaffer 120 and a sieve 150 . In operation, the grain and chaff mixture is delivered to the front of the chaffer 120 from the separator mechanism 20 . The chaffer 120 is shaken or vibrated so as to move the crop along over the surface of the chaffer 120 toward the rear of the combine 10 in the direction of the arrow. Heavier grain falls through openings in the chaffer 120 onto the sieve 150 below the chaffer 120 . The final cleaning is done in the sieve 150 . In some combines 10 , a fan 102 blows air into or across the cleaning shoe 100 to blow the lighter chaff and straw away from the grain in the chaffer 120 . The sieve 150 is also shaken or oscillated so as to move the crop along over the surface of the sieve 150 toward the rear of the combine 10 in the direction of the arrow shown. In some arrangement of combines 10 , the sieve 150 oscillates with the chaffer 120 , and in other combines 10 , the sieve 150 oscillates in a direction counter to the chaffer 120 . The grain falls through openings in the sieve 150 into the clean grain auger 170 , and is carried from there to the grain tank 180 .
As can be seen in FIG. 2 , the cleaning shoe 100 has a frame 110 to which the chaffer 120 , with the sieve 150 below the chaffer 120 , are mounted or suspended. In many combines 10 , the chaffer 120 is a single unit mounted in a frame having edges 121 along the outside length. In other combines 10 , especially those which are used on sloping ground, the chaffer 120 is divided into a series of two or more longitudinal sections 122 mounted in the frame 121 , extending the length of the chaffer 120 as shown in FIG. 2 . Similarly, the sieve 150 can also be a single unit mounted in a frame having edges 151 along the outside length, or can have a series of two or more longitudinal sections 152 mounted in and extending the length of the sieve 150 . The chaffer 120 and sieve 150 have a plurality of openings 124 , 154 contained therein. The position, shape, size and number of openings can be varied to reflect the type of crop being harvested, and the size of the openings 124 in the chaffer 120 is can be different from the size of the openings 154 in the sieve 150 .
The present invention is designed to work with both single-surface chaffers and sieves (not shown) and those having a plurality of longitudinal sections 122 , 152 as shown in FIG. 2 . Additionally, it has been found that having at least one of the chaffer 120 or sieve 150 containing multiple longitudinal sections 122 , 152 results in increased efficiency when operating the combine 10 on a slope, and thus is a preferred embodiment. When the chaffer 120 and/or sieve 150 have a plurality of longitudinal sections 122 , 152 , there are dividers 126 , 156 between the longitudinal sections. The dividers 126 , 156 typically form a seal between and along the edge of the adjacent longitudinal section 122 , 152 to prevent grain and/or crop material from falling through the gaps between the dividers 126 , 156 and the longitudinal sections 122 , 152 that are created when the combine 10 utilizing a cleaning shoe 100 of the present invention is operated on a slope and the longitudinal sections 122 , 152 are tilted at an angle. In operation, the dividers 126 , 156 work like the outside edges 121 , 151 and provide a surface against which grain can accumulate when the combine 10 is leaning in that direction when operating on a slope. With dividers 126 , 156 the grain is compartmentalized, thus limiting the amount of grain that accumulates against the edge 121 , 151 or any one divider 126 , 156 , thus improving efficiency of the cleaning shoe 100 .
When used with the present invention, the frame of the chaffer 120 and/or sieve 150 is configured with a pivot linkage mechanism to pivot or tilt about the longitudinal axis relative to the combine 10 . For chaffers 120 or sieves 150 having a plurality of longitudinal sections 122 , 152 , each of the longitudinal sections 122 , 152 is configured to pivot or tilt about the longitudinal axis relative to the combine 10 . This is achieved by means of pivot pins 130 , 160 at each end of the chaffer 120 or sieve 150 that provide a pivoting longitudinal axis. However, in some arrangements of the present invention, a single long tube, wire or shaft (not shown) runs down the length of the chaffer 120 or sieve 150 , rather than interconnected pins used on each end. When a chaffer 120 or sieve 150 has multiple longitudinal sections, pins 130 , 160 are used at the ends of each longitudinal section 122 , 152 so that each longitudinal section 122 , 152 can be pivoted.
The pins 130 , 160 are connected to a motor-driven adjusting mechanism 200 that moves the longitudinal sections 122 , 152 along the longitudinal axis, the mechanism 200 being capable of sufficient control to move the longitudinal sections to various angle for operation. Typically, an electric motor is used with the adjusting mechanism, although it can be appreciated that other types of drive devices, such as a weight-driven or hydraulic control system can be used as well. Additionally, in some arrangements of the present invention, a manual adjusting system can be used in addition to the motor-driven adjusting mechanism to enable the operator to make additional adjustments to the mechanism.
As shown in FIG. 3 , a control system 210 is attached to the motor driven adjusting mechanism 200 , which controls movements of pivot linkage system. The control system 210 can also receive information from the vehicle Electronic Control Unit (ECU) 300 about combine speed, harvesting rates, and other factors that are relevant to operation of this system. In some arrangements of the present invention, only one of the chaffer 120 or sieve 150 is configured to provide for over-compensation, while in other arrangements of the present invention, both the chaffer 120 and sieve 150 are configured to provide for over-compensation. Additionally, in some arrangements of the present invention, an additional sub-control system 210 ′ (not shown) is typically located in the cab 15 of the combine 10 , which the operator can use to receive information from the detector mechanism 220 , and input information to command the motor 200 for manual operation or override of the automated control system 210 . A detector mechanism 220 is attached to at least one longitudinal section 122 , 152 , or the frame 110 , and is used to detect when the combine 10 is operating on a slope. The detected angle of slope is fed back from the detector mechanism 220 to the control system 210 and/or 210 ′. Based on the information about the operating slope, the control system 210 can determine the ideal over-compensating operating angle A oc , and the control system 210 can send commands to the motor 200 to tilt the longitudinal sections 122 , 152 , or entire chaffer 120 or sieve 150 to an angle equal to and opposite of the slope of the land plus an angle determined necessary to over-compensate for the slope of the ground, as shown in FIG. 3 . For an arrangement of the invention having an operator override system, the cab control system 210 ′ can also be used to select a desired operating angle and send commands to the motor 200 as to the preferred over-compensation angle for the longitudinal sections 122 , 152 or entire chaffer 120 or sieve 150 .
The function of the system in operation is represented in FIG. 4 . The detector mechanism 220 monitors the combine 10 operation and sends signals to the control system 210 on a regular basis. In operation, when the combine 10 is operating at a laterally inclined angle, at step 410 , a signal is sent from the detector mechanism 220 to the control system 210 about the angle of the operating slope. In arrangements of the present invention having an operator override or manual control system 210 ′, the information from the detector mechanism 220 is sent to that control system 210 ′ as well. When at step 412 the control system 210 receives more than a pre-defined number of signals that the combine 10 is operating on greater than a pre-defined level of slope, the over-compensation system of the present invention will be activated. If no, or insufficient slope information, or an insufficient change in slope from the prior slope is detected by the detector mechanism 220 , the present invention will not be activated.
At step 420 , the control system 210 will take the information received from the detector mechanism 220 about the operating angle of the combine 10 , and can collect information from the combine ECU 300 about the current operating speed of the combine, and if suitable for the specific arrangement of the invention, other information such as current harvesting rate, type of crop being harvested, tipping ability of the cleaning shoe, and/or numerous other factors, and calculate the preferred over-compensation angle that would improve grain cleaning efficiency. One very simple formula that could be used to calculate the tilt angle A T needed to over compensate would be to take the current combine operating angle A c, and multiply it by a specified value V to achieve the tilt angle A T , the amount by which the longitudinal sections 122 , 152 should be moved to achieve the appropriate over-compensation angle A oc . For example, a standard value for V could be −2. If the combine operating angle A c is 6°, when it is multiplied by −2, the tilt angle A T would be −12°. The control system 210 would move the longitudinal sections 122 , 152 for −12° from the current position in the opposite direction; this would bring the longitudinal sections 122 , 152 to an over-compensation angle A oc of −6° from level. Other standard values for V could be used, such as −1.2, −1.5, etc. The standard value used could be varied depending on factors such as the crop type (i.e. corn, soy beans) being harvested. Other more complex formulas using other information and factors, such as those mentioned above, could also be used. It can be appreciated that different formulas can be used to calculate different over-compensation angles for the chaffer and sieve, or the same formula and angle used for both mechanisms.
At step 425 , if the system is configured to operate in automatic mode, then at step 440 , the control system 210 sends a signal to the motor 200 to activate the pivot linkage mechanism 140 and move the longitudinal sections 122 , 152 or complete chaffer 120 and/or sieve 150 to the correct over-compensation angle to improve grain cleaning efficiency. At step 425 , if it is determined that the system is set up to operate in manual/override operation, then at step 430 , the operator can use the override control sub-system 210 ′ to send commands to the motor 200 as to the desired over-compensation operating angle, if different from the calculated over-compensation angle. The operator can have access to the information collected by the control system in 420 , including the calculated angle, for use in specifying an operating angle.
The detection mechanism 220 will continue to provide information about the current operating slope to the control system 210 . The control system 210 will compare the inputs received to the previous inputs and determine if there has been a change in the operating slope, and if so, if the change is sufficient to recalculate the preferred overcompensation. In some arrangements of the present invention, the system can be configured to determine if the change in angle has continued for a specified number of inputs before recalculating the over-compensation angle. If so, then at step 420 the control system will calculate a new preferred angle and send the information to the automated control system 210 or the operator's control system 210 ′ if the system is in manual/override operation if the new preferred angle does not equal the current position angle.
In some arrangements of the present invention, each longitudinal section can be positioned at the same over-compensating angle, or each longitudinal section can be adjusted to a different angle so as to appropriately over-compensate and maximize efficiency. For example, the longitudinal section on the furthest downhill side may be tilted at a greater angle than the adjacent or any other uphill longitudinal sections. If the system 210 has determined that for best yield the longitudinal sections 122 , 152 should be at more than one angle, that information can be sent to the motor 200 . If the system is not operating in automatic mode, the operator can use this information to manually adjust the longitudinal sections 122 , 152 to the desired angle using the sub-control system 210 ″ in the cab 15 .
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.
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A system and method for limiting crop loss when harvesting on sloped or rolling ground by adjusting the chaffer and/or sieve, or longitudinal sections thereof, so as to overcompensate for the ground slope so that the chaffer and/or sieve sections are actually inclined away from horizontal opposite the direction of ground slope at a selected angle. Such overcompensation increases crop harvesting efficiencies over systems that simply work to level the chaffer and/or sieve sections, without the high expenses associated with a combine having a pivoting axle.
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This application is the US national phase of international application PCT/GB01/00092 filed 10 Jan. 2001 which designated the U.S.
BACKGROUND
1. Technical Field
The present invention relates to a method of operating a datagram network.
2. Related Art
In recent decades, packet networks (i.e. networks that break a message up into separate parts) have become popular since they allow an efficient sharing of network resources between different users. The Internet is an example of one species of packet network, namely datagram networks (i.e. networks in which packets include a destination address unique to that network).
In his paper, ‘IETF Multiprotocol Label Switching (MPLS) Architecture’, presented at the 1 st IEEE International Conference on ATM in June 1998, Francois Le Facheur describes an MPLS network. MPLS technology is likely to be widely implemented within the so-called backbone networks of the Internet. MPLS is one form of label switched network. In such a network, a label of only local significance is used by each node in determining how to forward a packet. An advantage of a label switched network over a datagram network is that a common label can be assigned to packets belonging to different messages. Packets having similar labels are processed uniformly. That results in a reduction in the amount of processing carried out by nodes within the label-switched network.
It is possible to achieve the same benefit in situations where a group of senders send packets to a single receiver (as might happen when a MPLS network operator provides a Virtual Private Network, for example). In that case, at each node in the network where flows from different senders converge, packets are received with different labels but forwarded with the same label. All packets being sent across the VPN therefore arrive at the sender with the same label. It will be realised that this aggregation leads to the processing burden placed on nodes near the receiver being lessened.
In their paper ‘Concast: Design and Implementation of a New Network Service’ available from the Proceedings of the 7 th Annual International Conference on Network Protocols (October/November 1999), Kenneth L. Calvert et al, propose a method of many-to-one communication for use in the Internet. The aim of the method is to discard copies of a packet already sent to the receiver by another sender in the group. It will be seen that, as with many-to-one communications in an MPLS network, this reduces the burden on nodes closer to the receiver.
BRIEF SUMMARY
According to a first aspect of the present invention, there is provided a method of operating a datagram network comprising at least three nodes having respective external links to a subnetwork, said datagrams being constructed in accordance with a protocol that specifies a first set of predetermined locations in said datagram to represent a source address, said method comprising:
operating each of a group of two or more of said nodes as a sender node to transmit one or more datagrams with a common group identifier in said first set of predetermined locations to one of said nodes which is operating as a recipient node, the transmission taking place via: the sender node's external link to the subnetwork, the subnetwork, and the recipient node's external link to said subnetwork; and operating said subnetwork to forward said datagram across said subnetwork in a manner dependent upon said common group identifier value in said first set of predetermined locations.
By using the source address field of the datagram for group identification, the capacity of the datagram network is used efficiently (since the size of the header of the datagram is not increased as it would be by a separate indication of group membership in the datagram). Furthermore, operating the datagram network to forward datagrams in a manner dependent on the group identifier, results in a reduction in the processing load placed on the datagram network.
It is to be understood that the subnetwork may contain any number of switching elements interconnected via internal links (and not all the switching elements need be connected directly to one another). In particular, the subnetwork may comprise a single switching element.
Preferably, said subnetwork operating step comprises operating said subnetwork to forward said datagram over the external link leading to a recipient node selected in dependence upon said common group identifier value in said first set of predetermined locations. Routing the datagram in dependence upon the common group identifier reduces the processing load placed on the subnetwork.
In preferred embodiments, said subnetwork includes, for each of said groups, stored data representing one or more routing trees associated with said group, said stored data comprising, for each routing tree, routing tree data identifying one of said external links as a root-bound external link in relation to said routing tree and a plurality of others of said external links as leaf-bound external links in relation to said routing tree; furthermore
datagrams having a common group identifier are forwarded over the external link defined as the root-bound external link in relation to the routing tree that corresponds to the group identifier value in said first set of predetermined locations in those datagrams; and
said protocol further defines a second set of predetermined locations to represent a destination address, said method further comprising:
operating one of said nodes to send one or more datagrams with said common group identifier in said second set of predetermined locations; and operating said subnetwork, on receipt of a datagram with said common group identifier in said second set of predetermined locations, to forward said datagram over the leaf-bound external links associated with said routing tree for said group.
In this way the same data can be used both for routing datagrams from a selected node of a group to all the other nodes in a group and for routing from any one of the other nodes to the selected node. This results in further savings in the storage and processing burdens placed on the switching elements of the subnetwork. Note that this is achieved without any increase in the size of the datagram header. Many multicast routing algorithms are known (e.g. Distance Vector Multicast Routing Protocol (DVMRP), Multicast extensions to Open Shortest Path First (MOSPF)), which can be used to generate the tree-defining data. Furthermore, a capability for handling datagrams having a group identifier in their source address field need only be provided in specialised nodes which are also capable of handling multicast datagrams.
Further preferably, said datagram forwarding step further comprises:
identifying those external links defined as leaf-bound external links in relation to the common group identifier value in said first set of predetermined locations; and discarding said data block if it was not received over one of said leaf-bound external links.
This prevents the subnetwork forwarding a datagram that falsely purports to have been sent by a member of the group.
In some embodiments, said subnetwork operating step comprises forwarding said datagram across said subnetwork with a priority which is dependent on said common group identifier.
In preferred embodiments, said method further comprises the steps of:
operating said sending node to append a common group identifier value to a received data block before sending the datagram thus formed to said recipient node, said common group identifier value being appended so as to be located in said first set of predetermined locations; operating said recipient node to remove the common group identifier value before onward transmission of the data block.
Those skilled in the art will recognise that this embodiment involves ‘tunnelling’ a datagram across the subnetwork. The tunnel thus formed is a multipoint-to-point tunnel. Tunnelling has a number of advantages. Firstly, the header information present in the datagram before the common group identifier was appended can be re-used at the recipient node and in any network beyond that node. This may be used to provide a Virtual Private Network which uses a shared subnetwork. The original header information can be encrypted without affecting the operation of the subnetwork, thereby providing security for the communication between the sender and the recipient.
BRIEF DESCRIPTION OF THE DRAWINGS
There now follows a description of specific embodiments of the present invention. These embodiments are described by way of example only with reference to the accompanying drawings, in which:
FIG. 1 is an illustration of an internetwork operating in accordance with a first embodiment of the present invention to interconnect a number of Local Area Networks (LANs);
FIG. 2 is a more detailed illustration of the internetwork of FIG. 1 ;
FIG. 3 is a flow-chart which shows how a router of the internetwork of FIG. 2 operates in accordance with the first embodiment;
FIG. 4 is a flow-chart which shows part of the operation of FIG. 3 in more detail;
FIG. 5A shows the format of a multicast IP packet sent by a computer on one of the LANs of FIG. 1 to a computers on a selection of the other LANs;
FIG. 5B shows the format of a multicast tunnel packet which is used in transmitting the packet of FIG. 5A across the internetwork of FIG. 2 ;
FIG. 5C shows the format of a unicast IP packet sent by a computer on one of the LANs that receives the packet of FIG. 5A back towards the LAN from which the packet of FIG. 5A was sent;
FIG. 5D shows the format of a many-to-one tunnel packet which is used in transmitting the packet of FIG. 5C across the internetwork of FIG. 2 ;
FIG. 6A illustrates a routing tree for a one-to-many communication; and
FIG. 6B illustrates a reversed version of the routing tree of FIG. 6A for use in a many-to-one communication.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
FIG. 1 shows a shared internetwork S which interconnects six Local Area Networks (A to F). The six LANs (A to F) are connected to the shared internetwork S via six respective links (L 1 to L 6 ). Each LAN (A to F) comprises a number of computers connected to one another and to a gateway computer (G 1 to G 6 ) by a broadcast network (SL 1 to SL 6 ). Broadly, the shared internetwork S and Local Area Networks (A to F) operate in accordance with the IP protocol suite.
The computers A 1 to F 3 , the gateway computers G 1 to G 6 , and the routers that operate in the shared internetwork S ( FIG. 2 : R 1 to R 6 ) are all types of nodes. In accordance with the IP protocol suite, each interface between a node and a network link is associated with a unique 4-byte address. These 4-byte addresses are normally written as four decimal digits each of which represent the decimal value of a respective byte—for example the address associated with the interface between the computer A 1 and the shared link SL 1 , might be 172.16.0.2. One possible configuration of IP addresses for the LANs of FIG. 1 is given in Table 1 below:
TABLE 1
Interface
IP address
Interface
IP address
Interface
IP address
A1 to SL1
172.16.0.1
B1 to SL2
172.17.0.1
C1 to SL3
172.18.0.1
A2 to SL1
172.16.0.2
B2 to SL2
172.17.0.2
C2 to SL3
172.18.0.2
A3 to SL1
172.16.0.3
B3 to SL2
172.17.0.3
C3 to SL3
172.18.0.3
G1 to SL1
172.16.0.4
G2 to SL2
172.17.0.4
G3 to SL3
172.18.0.4
G1 to L1
194.10.2.1
G2 to L2
194.10.3.1
G3 to L3
194.10.4.1
D1 to SL4
172.19.0.1
E1 to SL5
172.20.0.1
F1 to SL6
172.21.0.1
D2 to SL4
172.19.0.2
E2 to SL5
172.20.0.2
F2 to SL6
172.21.0.2
D3 to SL4
172.19.0.3
E3 to SL5
172.20.0.3
F3 to SL6
172.21.0.3
G4 to SL4
172.19.0.4
G5 to SL5
172.20.0.4
G6 to SL6
172.21.0.4
G4 to L4
194.10.6.1
G5 to L5
194.10.7.1
GG to L6
194.10.9.1
Those skilled in the art will recognise that the IP addresses assigned to the interfaces within the LANs (A to F) are private IP addresses. Packets having private IP addresses in their destination address field are not forwarded by routers in the public Internet (and, in the present example, are not forwarded across the shared internetwork S). In contrast, the addresses assigned to the interfaces between the gateway computers (G 1 to G 6 ) and the links (L 1 to L 6 ) leading to the shared internetwork are public IP addresses.
A more detailed diagram of the shared internetwork S is given in FIG. 2 . The internetwork S comprises six routers (R 1 to R 6 ), each of which has four physical communication ports. One of the communication ports of each router (R 1 to R 6 ) receives a link (L 1 to L 6 ) to a respective one of the Local Area Networks (A to F). The other three communication ports receive links to respective other routers.
In more detail, a western central router R 3 is directly connected via a central link CT to an eastern central router R 4 and also to a north-western router R 1 and south-western router R 5 via a north-western link NW and south-western link SW respectively. Similarly the eastern central router R 4 is directly connected to a north-eastern router R 2 and a south-eastern router R 6 via a north-eastern link NE and a south-eastern link SE respectively. A northern link N directly connects the north-eastern R 1 and north-western R 2 routers. An eastern link E directly connects the north-eastern R 2 and south-eastern R 6 routers. A western link W directly connects the north-western R 1 and south-western R 5 routers. Finally, a southern link S directly connects the south-western R 5 and south-eastern R 6 routers.
A possible configuration of the IP addresses for the interfaces between the internetwork nodes of the internetwork S and the links (L 1 to L 6 , N, S, E, W, NE, SE, SW, NW, CT) is given in Table 2 below:
TABLE 2
Interface
IP Address
R1 to L1
194.10.1.2
R1 to N
194.10.25.1
R1 to NW
194.10.18.2
R1 to W
194.10.15.2
R2 to L2
194.10.2.2
R2 to N
194.10.25.2
R2 to NE
194.10.11.2
R2 to E
194.10.20.1
R3 to L3
194.10.3.2
R3 to CT
194.10.12.1
R3 to NW
194.10.18.1
R3 to SW
194.10.10.2
R4 to L4
194.10.4.2
R4 to CT
194.10.12.2
R4 to NE
194.10.11.1
R4 to SE
194.10.13.2
R5 to L5
194.10.5.2
R5 to W
194.10.25.1
R5 to SW
194.10.10.1
R5 to S
194.10.14.2
R6 to L6
194.10.6.2
R6 to E
194.10.20.2
R6 to SE
194.10.13.1
R6 to S
194.10.14.1
Those skilled in the art will see that a Class C address has been assigned to each link (L 1 to L 6 , N, S, E, W, NE, SE, SW, NW, CT). The links in this case are provided by Permanent Virtual Circuits set up in an Asynchronous Transfer Mode network that provides the shared internetwork S.
Each of the gateway computers (G 1 to G 6 ) and the routers (R 1 to R 6 ) operates in accordance with the Open Shortest Path First dynamic routing process (defined in Request For Comments (RFC) 1247 available from the Internet Engineering Task Force (IETF)—contactable at 11150 Sunset Hills Road, Suite 100, Reston, Va. 20190-5321, USA). Hence, each router (R 1 to R 6 ) generates a unicast routing table which indicates which of the router's interfaces provides the best route towards any reachable network. An example of such a routing table is given for the north-eastern router R 2 in Table 3 below:
TABLE 3
Best Output
Destination Address
Interface
172.16.x.x [i.e. LAN A]
194.10.25.2
172.17.x.x [i.e. LAN B]
194.10.2.2
172.18.x.x [i.e. LAN C]
194.10.25.2
172.20.x.x [i.e. LAN D]
194.10.11.2
172.21.x.x [i.e. LAN E]
194.10.25.2
172.22.x.x [i.e. LAN F]
194.10.20.1
Comparison with Table 1 will show how each of the entries on the left-hand side of Table 3 refers to one of the Local Area Networks (A to F). (Note that the information in square brackets is not actually stored in the router—it is included for the convenience of the reader). The right-hand column of Table 3 indicates from which interface of the north-eastern router R 2 a packet with a destination address listed in the left-hand column is to be sent.
Both the gateway computers (G 1 to G 6 ) and the routers (R 1 to R 6 ) operate in accordance with the Distance Vector Multicast Routing Protocol (defined in RFC 1075 available from the IETF). This results in each router (R 1 to R 6 ) further storing a multicast routing table which lists for each multicast group that is routed via that router:
for each computer in the multicast group that may act as a source node: i) an indication of the interface through which packets addressed to that multicast group should be received; and ii) an indication of the interface(s) through which multicast packets addressed to that multicast group are to be forwarded.
By way of example, assume the operator of the shared internetwork S provides a Virtual Private Network (VPN) that interconnects LANs A,B,D and F (this might be required where those LANs belong to the same organisation).
To provide the VPN the network operator firstly configures gateway computers G 1 , G 2 , G 4 and G 6 to be members of a multicast group associated with an IP address, say 230.10.10.1. Each of the elements of the shared internetwork S then operate in accordance with the DVMRP algorithm to generate entries relating to that multicast group in their multicast routing tables. The multicast routing table entry stored in the north-eastern router R 2 might then appear as shown in Table 4 below:
TABLE 4
Best Input
Output
Source Address
Destination Address
Interface
Interfaces
194.10.1.1
230.10.10.1
194.10.25.2
194.10.2.2
[i.e. G1]
[i.e. G1, G2, G4, &G6]
194.10.11.2
194.10.20.1
194.10.2.1
230.10.10.1
194.10.2.2
194.10.25.2
[i.e. G2]
[i.e. G1, G2, G4, &G6]
194.10.11.2
194.10.20.1
194.10.4.1
230.10.10.1
194.10.11.2
194.10.25.2
[i.e. G4]
[i.e. G1, G2, G4, &G6]
194.10.2.2
194.10.20.1
194.10.6.1
230.10.10.1
194.10.20.1
194.10.25.2
[i.e. G6]
[i.e. G1, G2, G4, &G6]
194.10.2.2
194.10.11.2
The internetwork operator also configures each of the computers in the LANs A,B,D and F to address packets intended for one or more computers in all those LANs to multicast address 235.255.255.255.
The internetwork operator then places configuration data in the gateway computers G 1 , G 2 , G 4 and G 6 . That configuration data associates destination addresses with tunnel data—the tunnel data at G 1 , for example, might be as follows:
TABLE 5
Source Address of packet
Destination Address of
Contents of Destination
for onward transmission
packet for onward
Address Field of packet
across shared internetwork
transmission across shared
from LAN A
S
internetwork S
172.17.x.x [i.e. LAN B]
230.10.10.1
194.10.2.1
172.19.x.x [i.e. LAN D]
230.10.10.1
194.10.4.1
172.21.x.x [i.e. LAN F]
230.10.10.1
194.10.6.1
235.255.255.255
194.10.1.1
230.10.10.1
In accordance with the first embodiment, a router (R 1 to R 6 ) is programmed to carry out the processes illustrated in FIG. 3 on receiving an IP packet. It is to be understood that the flow-chart shows the processes only to the extent required to explain the present embodiment—processes that are carried out in conventional routers (such as header verification and error checking) are also carried out in the present embodiment but not discussed here.
Firstly, if the source address field of the received packet is in the range 224.0.0.0 to 239.255.255.255 (step 601 ) then a many-to-one forwarding process (step 602 ) is carried out (explained in more detail below in relation to FIG. 4 ). If the source address is not in that range then, if the destination address contained within the received packet is in the range 0.0.0.0 to 223.255.255.255 (step 603 ) the router carries out conventional unicast forwarding (step 604 ) based on the destination address and its unicast routing table (Table 3). After unicast forwarding (step 604 ) the process ends (step 607 ). If the destination address contained within the received packet is instead in the range 224.0.0.0 to 239.255.255.255 (step 605 ) the router carries out conventional multicast forwarding (step 606 ) based on the destination address and its multicast routing table (Table 4). After multicast forwarding (step 606 ) the process ends (step 607 ). Also, if neither the source address nor the destination address is within the above ranges then the process ends (step 607 ).
As shown in FIG. 4 , the many-to-one forwarding (step 602 ) starts at step 701 . Firstly, the multicast routing table is searched for an entry for a multicast group (i.e. the second column of Table 4 is searched) having the same address as the source address contained within the received packet (step 702 ). If a matching entry in the multicast routing table (Table 4) is not found, then the packet is discarded (step 710 ) before the many-to-one forwarding process ends (step 705 ).
If one or more entries corresponding to the multicast address contained within the source address field of the received packet are found in step 702 then a search is carried out for an entry which also has a source address which corresponds to the destination address in the received packet (i.e. the first column of Table 4 is searched). Again, if no such entry is found, then the packet is discarded (step 710 ). If such an entry is found, then the received packet is forwarded (step 704 ) from the interface listed as the best input interface in that entry (i.e. the interface listed in the third column of Table 4). The many-to-one forwarding process then ends (step 705 ).
An example of the operation of first embodiment will now be given. In this example, the network has been configured as explained above and as illustrated in the accompanying diagrams and tables.
A user of the computer A 1 instructs it to send an IP packet to computers B 1 , D 1 and F 1 Following its configuration, the computer A 1 then sends a packet having a source address field which gives the IP address associated with the interface between A 1 and the shared link SL 1 (i.e. 172.16.0.1) and a destination address field 235.255.255.255. The packet is shown in FIG. 5A .
This packet is received by the gateway computer G 1 which notes that the destination address is one of those to be tunnelled (from Table 5) and therefore appends a header to the packet to create a tunnel packet. The tunnel packet uses the multicast address associated with the VPN and is illustrated in FIG. 5B .
The gateway computer then sends the tunnel packet over link L 1 to the shared internetwork S. Since the source address is not in the range 224.0.0.0 to 239.255.255.255 and the destination address is in the range 224.0.0.0 to 239.255.255.255, each of the routers carries out conventional multicast forwarding (step 606 in FIG. 3 ). The shared internetwork thus multicasts the packet in a conventional manner to the recipient LANs B, D and F. A routing tree showing how the routers of the network would forward the packet is illustrated in FIG. 6A . The header of the tunnel packet is then removed at each of the recipient LANs (B, D, and F) and the packets forwarded to the destination computers in a conventional manner.
To continue the example, a user of computer F 3 on LAN F might instruct that computer to send a packet to computer A 1 on LAN A. The packet sent by computer F 3 onto LAN F has a conventional format as shown in FIG. 5C .
On receipt of the packet at the gateway computer G 1 , the gateway computer looks up a Table equivalent to Table 5 above forms a tunnel packet containing the packet sent from computer F 3 . In accordance with that table, the value 230.10.10.1 is placed in the source address field of the tunnel packet, and the value 194.10.1.1 is placed in the destination address field of the tunnel packet. The tunnel packet is shown in FIG. 5D .
Packets having a multicast address can be generated by running the FreeBSD operating system program on each of the gateway computers G 1 to G 6 . Other operating systems may also be used, but any part of the program that prevents the generation of packets having a source address in the range 224.0.0.0 to 239.255.255.255 will have to be removed.
Each of the routers receiving the many-to-one tunnel packet will carry out many-to-one forwarding (step 602 ) after finding that the source address of the many-to-one tunnel packet is in the range 224.0.0.0 to 239.255.255.255 (in step 601 ). The routes followed by many-to-one packets from LANs B,D, and F to LAN A are illustrated in FIG. 6B . It will be seen that the routes are the reverse of those shown in FIG. 6A and followed by multicast packets sent from LAN A.
It will be realised that both the tunnel packets mentioned above ( FIGS. 5B and 5D ) would be forwarded by router R 2 using its multicast routing table (Table 4). It will be seen that both the many-to-one communication and the one-to-many communication use the same routing table entries. Hence, the number of routing entries that need be stored in the router R 2 in order to forward packets from one of the members of the VPN to the others and from one of the members to another member, is reduced. Thus the amount of memory required at R 2 is reduced as is the processing time required to search the routing table for the appropriate entry. Thus a packet forwarding technology is provided that can alleviate concerns about the ability of the core of a network to handle real-time packets.
The new forwarding mode enables computers within a multicast group to send a packet to another member of the group anonymously. This is useful in relation to remote anonymous voting and the like.
Also, routers can be set up to respond to packets of the new type by forwarding packets received from any member of selected group more quickly than those received from other sources. The use of a group source address removes the requirement for the routers of the shared internetwork S from storing and maintaining lists of which computers are present in which groups. In general, the multicast source addresses of packets of the new type can be used to provide any differentiation of service that might be provided by say, the Forward Equivalence Class to be used in proposed Multiprotocol Label Switched networks.
In a preferred embodiment, the many-to-one forwarding process ( FIG. 4 ) includes a further input interface checking step immediately before the forwarding step 704 . In the input interface checking step it is checked to see whether the packet has been received on one of the output interfaces (i.e. the fourth column of Table 4) associated with the entry found in step 703 . If it was not received on one of those interfaces then the packet is discarded.
It will be seen how the preferred embodiment prevents computers on LANs which do not contain members of the multicast group from sending many-to-one packets which have the address of that multicast group in their source address field. In this way, computers which are not in the group are unable to take advantage of services intended only for group members. In order to control membership of the multicast group, methods such as those used in the Remote Authentication Dial In User Service (RADIUS) and the improvement thereof known as DIAMETER.
Although the above embodiment described the routers operating in accordance with the Distance Vector Multicast Routing Protocol (a protocol that builds so-called ‘source-based trees’), it is to be understood that so-called ‘shared tree’ multicast routing protocols, such as Core-Based Tree might also be used.
As another variation, those skilled in the art will realise that the payload of the tunnel packet (which includes the header of the original packet) might be encrypted to provide security for the communication across the shared internetwork S.
In the above embodiment, all of the routers operated a many-to-one forwarding process. However, the embodiment is also of benefit in networks were only a subset of the routers operate such a process. That is because conventional routers will forward a packet based on its destination address, ignoring the source address field—i.e. they will not carry out steps 601 and 602 of FIG. 4 .
It will be realised that the present invention could be used in relation to a number of protocols other than IP version 4 mentioned above. Clearly, it could be used in relation to IP version 6.
Further embodiments of the present invention are similar to the above-described embodiments but have area edge routers in place of the gateway computers (G 1 to G 6 ). It will be realised that such an embodiment can provide differentiated services based on an address carried in an IP packet rather than on a label that would be attached to the packet in accordance with Multiprotocol Label Switching protocols.
Although, in the above embodiment, the internetwork S was configured to use ‘tunnelling’ to provide sites A,B,D & F with a Virtual Private Network, many of the advantages of the present invention would still pertain were the tunnelling feature to be removed. The multicast groups would then have hosts as members and it would be necessary to use public Internet addresses within the sites A to F. Furthermore, without tunnelling, the advantages would be achieved without increasing the size of the IP packet header.
All the above embodiments described the re-use of multicast routing tables, some embodiments of the present invention might not make use of the multicast routing tables—for example, packets from A,B,D, & F could be provided with a Group E source address, the switching elements of the internetwork S operating to route the packets on the basis of that source address and a routing table that is provided at the switching elements by the network operator.
As a further alternative, routing could be carried out conventionally, but with scheduling processes being carried out in dependence on the Group E source address.
Any address value could be used In the source address field to represent the group. Group E source addresses are usefully employed since IP version 4 has not assigned any meaning to them.
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A datagram network is operated by placing a group address in the source address field of the datagram. Nodes within the datagram network forward the datagram in dependence on the contents of the source address field. This provides many of the scalability advantages offered by Multiprotocol Label Switched (MPLS) networks without introducing the overheads caused by connection set-up in MPLS networks. The method can also easily provide different quality of service levels to different types of packets and is especially useful in providing Virtual Private Networks across a shared internetwork such as the public Internet.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to alarm devices and more particularly relates to a latch monitor which provides an indication of door latch or deadbolt position to an alarm system.
2. The Prior Art
Various types of monitoring systems are available in the prior art, usable in connection with closable openings such as doors and windows and which are electrically connected to a monitoring circuit to provide an indication of the position of the closure. However, it is highly desirable to have systems of this type which will also provide the user an indication that the latch or deadbolt associated with the closure is properly engaged as it is possible that a closure, such as a door, may be shut and the deadbolt or latch not properly engaged in the strike, leaving the door other closure in an unsecured position. Because of this need, there are a number of latch or bolt security devices in the prior art as represented by the following:
U.S. Pat. No. 5,257,841, issued to Geringer et al, discloses a lock strike device which has a strike box with spaced side walls and a closed rear wall and is electrically connectable to a monitoring circuit. A first side wall and a portion of the rear define a cut-out through which an elongated blade to trigger a spring bias into the strike space. The trigger is hinged at its front end to a box connected to the front of the side wall. The rear end of the trigger comprises a head which urges a spring-loaded lever of an electrical switch mounted on the exterior of the housing rear into an open circuit position. A movable tab extends transversely into the space from the trigger and the tab senses the presence of a latch to provide a signal to an indicator. This device, while effective in many applications, requires relatively precise adjustment of the head of the trigger to insure engagement with the latch or bolt and may not always be properly performed. Also, since the switch is located on the rear of the housing, a substantial opening or aperture in the door frame is required for mounting this device. The trigger assembly also incorporates a number of precision parts increasing cost and reducing durability and reliability in use.
Another unit presently available in the commercial marketplace is the VonDuprin Model 4582 monitor strike which is manufactured by a division of Ingersoll Rand. This unit incorporates a replacement strike plate which mounts a mechanical switch behind it with a switch trigger protruding into the strike opening so that entry of the latch into the opening depresses a trigger. There are drawbacks with this unit. Installation is costly as a special cut-out needs to be made in the door frame. The manufacturing cost is high because the unit incorporates a replacement strike. Strikes are often made of expensive material such as brass or bronze for aesthetic architectural reasons. This device is located in a fixed position so that a multiplicity of units is necessary to accommodate the large number of various latches and deadbolts available on the market which are produced in different sizes and shapes and which are located in different vertical, lateral and depth positions with respect to the strike opening.
Another unit currently available is the ASSW-1048 Keeper Switch by Folger Adam. This unit addresses some of the disadvantages of the VonDuprin product. The Folger Adam unit retains the existing strike by mounting behind the existing strike. A series of slotted holes allow adjustment of the trigger switch, both vertically and depth wise to accommodate different latches and deadbolts. While this adjustment capability is advantageous as it enhances the use flexibility of the product, there is an associated drawback in that adjustment requires skilled labor and if done incorrectly will lead to a functional failure. The trigger is directly connected to the mechanical switch and rough handling of the door while the latch is engaged can damage the switch.
U.S. Pat. No. 4,465,997, entitled "Exterior Mounted Door and Window Alarm Switch", shows several embodiments of the invention and in each instance the unit is mounted on the exterior of the door frame which may be architecturally and aesthetically objectionable. Further, the installation of this unit require greater skill on the part of the installer as a precision opening must be cut into the door frame.
Accordingly, in spite of the numerous latch monitoring devices available in the prior art, there nevertheless exists a need for an improved latch bolt monitoring device which installs in a concealed manner behind the existing strike and which will work effectively with most all latches and deadbolts and which device does not require field adjustment. It is also highly desirable to have a device of this type which mechanically disconnects the associated switch from the remainder of the device when a latch or bolt is in the strike, therefore achieving maximum ruggedness and durability, as well as simplicity and low cost of manufacture.
SUMMARY OF THE PRESENT INVENTION
Briefly, the present invention provides such an improved latch or bolt monitoring device which has a rectangular housing open on one side to admit the latch or bolt. A pivot pin extends along one side wall and is mounted at opposite ends to the housing end walls. The pin pivotally supports a rocker plate which is spring biased to a rest position in which the strike plate surface of the rocker plate extends substantially across the length and width of the entire latch area opening within the housing. In the rest position, a flange engages and depresses the actuator on a switch mounted on the side of the housing to maintain the switch in a first condition. When a latch or deadbolt is extended into the latch area, the rocker plate is engaged and is pivoted further into the housing causing the flange to disengage from the actuator. This movement of the actuator changes the switch state to a second condition. In this condition, when the latch or bolt is properly within the strike area, the actuator is out of contact with the rocker plate flange so that even violent rattling of the door will not damage the switch.
In an alternate embodiment, multiple rocker plates are provided and a switch and actuator are associated with each of the rocker plates. This construction allows separate monitoring of the latch and deadbolt for a lock of the type that includes both components. In the first embodiment of the invention described above, the monitoring device will monitor the position of both the latch and deadbolt, but because the device has only a single rocker plate, the switch will be moved to the second condition when either the latch or the deadbolt enters the strike opening. With the alternate embodiment, both the latch and bolt may be separately monitored. The terms "latch", "latch bolt" and "bolt" as used herein, comprehend latches and deadbolts as well as any reciprocal member that is engageable in a locking device.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other objects and advantages of the present invention will be more fully appreciated and understood from the following description, claims and drawings in which:
FIG. 1 is an exploded perspective view of a preferred embodiment of the latch monitor of the present invention;
FIG. 2 is a perspective view of an alternate embodiment of the present invention, which embodiment will separately monitor a pair of latches or bolts or a combination thereof;
FIG. 3A is a cross-sectional view of the latch monitor showing the rocker plate in its normal, at rest position with the switch in a first condition;
FIG. 3B is a cross-sectional view of the latch monitor in which a bolt has been extended into the strike causing the switch to move to a second condition;
FIG. 4 is a front view of the latch monitor of FIG. 1;
FIG. 5 is a side view of the latch monitor of FIG. 1;
FIG. 6 is an exploded perspective view of the latch monitor of FIG. 1; and
FIG. 7 is an exploded perspective view of the latch monitor shown in FIG. 2.
DETAILED DESCRIPTION OF THE INVENTION
Turning now to the drawings, particularly FIGS. 1, 3A, 3B, and 4 to 6, the latch monitor 10 of the present invention is shown. The latch monitor includes a box-like housing 12 having a side wall 14, an opposite rectangular side wall 16 having a height slightly less than wall 14, end walls 18 and 20, and rear wall 22. Mounting tabs 24 and 26 are integrally formed with end walls 18 and 20, respectively, and are bent to form right angles with respect to the end walls. Elongate slots 25, 25A are provided in tabs 24, 26. The housing may be of any suitable material such as a rigid, durable plastic material fabricated by injection molding or may be metal suitably formed by stamping and bending operations. The housing defines an interior strike area 30 into which the latch and/or bolt extends when properly engaged.
A rocker plate, generally designated by the numeral 40, is integrally formed from a single piece of material such as stamped from a light gauge steel or aluminum. The rocker plate has a planar strike plate 42 having a flange 44 which extends generally at right angle with respect to the strike plate surface. The distal edge 46 of flange 44 is bent outwardly forming an L-shape. As best seen in FIGS. 4 and 6, relieved areas 48, 49, 50 and 51, are provided at spaced-apart locations along the intersection of the flange and strike plate. Recesses are provided at locations 55, 56 and 57 along the edge so that an axial pivot pin 60 may be axially inserted through the rocker plate along recesses 55, 56 and 57. The opposite ends of the pin 60 extend beyond the ends of the rocker plate 40 and are received in apertures 62, oppositely positioned in end plates 18 and 20. The pivot pin is secured in place by slip-on type retainer nuts 68 which engage the outer surface of the end walls 18 and 20.
A coil spring 70 having opposing arms 72, 74 is positioned about the pivot pin in one of the relieved areas, as for example, registering with area 51. One of the legs 72 is positioned in engagement with side wall 16 of the housing and the opposing arm 74 is placed in engagement with the underside of the rocker plate. In this way, a light biasing force is applied to the rocker plate in the direction of the arrow shown in FIG. 3A which maintains the rocker plate in this position at rest.
Mounted on the outer surface of side wall 16 is a switch 80 which may be a microswitch of the type manufactured by Honeywell or Omron. The switch carries a plurality of terminals 81, 82 and 83 to which wires may be conveniently connected to lead to an alarm system of the type manufactured by Ademco or Napco. These alarm systems are well known to those in the art and further detailed description is not necessary.
The switch 80 is secured to the side wall 16 by screws 85 and a rectangular gasket 86 may be interposed between the switch and the side wall. The switch has an actuator 90 shown as a pin which, in the mounted position, projects upwardly to a location slightly above the upper edge of side wall 16. In the assembled position, referring to FIGS. 1 and 3A, a portion of the edge of the rocker arm flange engages the actuator and the biasing force applied by spring 70 will cause the actuator to be depressed placing the switch 80 in a first state or condition. With the rocker plate in this position, which is considered the "at rest" position, the device will provide an indication to the alarm system that the closure, such as a door, is in an open position and that the associated bolt or latch is not properly seated in the strike.
FIG. 1 illustrates a typical mounting position for the latch monitor, it being understood that the latch monitor may be installed in association with any type of door or other closure. Normally, the device would be installed in a location such as a door frame 100 which is provided with a rectangular recess or cut-out 102, sized to accommodate the dimensions of the latch monitor housing 12 including sufficient lateral clearance for the side-mounted switch 80. The latch monitor is inserted into the opening 102 and the switch 80 suitably connected to wires 81, 82, 83, leading to the alarm system. The latch monitor is held in place by a conventional strike plate 110 having an opening 112 through which the bolt or latch associated with the closure can pass. As is conventional, the strike plate may be provided with a lip 116 to engage the bolt as the closure, such as a door, is pivoted to the closed position. The latch monitor is held in place by the strike plate which, in turn, is secured by fasteners such as screws 120. The slots 25, 25A are positioned to register with the holes 125, 125A in the strike plate.
In FIG. 3B, a closure, such as the door "D", is shown in the closed position and a latch or bolt, such as bolt 150, is moved or caused to be moved into the strike area 30. When this occurs, the bolt or latch 150 will strike the outer surface of the strike plate portion of the rocker plate 40 pivoting it inwardly as shown in FIG. 3B. Note the bolt or latch may enter strike area 30 at any vertical or lateral position and the rocker plate will still pivot as the rocker plate substantially occupies strike area 30. Entry of the bolt or latch will cause the flange 44 of the rocker plate to be pivoted upwardly allowing actuator 90 to extend, thereby moving the switch 80 to a second condition to provide an indication to the alarm system that the latch or bolt is in the proper engaged position. If the door is closed and the latch or bolt does not properly extend into the strike area 30 to cause the rocker plate to disengage the switch actuator, the proper alarm indication, either audio or visual, will not be provided and the occupants will be advised of a possible security problem.
Turning to FIGS. 2 and 7, an alternate embodiment of the present invention is generally designated by the numeral 200 and is constructed generally as described above with reference to embodiment 10. The principle difference is that embodiment 200 is provided with a plurality of rocker plates 240 and 240A which are independently, pivotally mounted on pivot pin 260 which extends longitudinally along the side wall 216 of receptacle 212. The side wall 216 is provided with a plurality of switches 280 and 280A secured by screws 285, each switch having an actuator 290 and 290A, respectively, which in the rest position are engaged by the flanges 246, 246A of the associated rocker plate. A suitable biasing spring 274, 274A is associated respectively with each of the rocker plates to normally urge the rocker plates to a position as seen in FIG. 3A. Each of the switches 280, 280A are connected to a alarm system, as has been described above.
The embodiment 200 is installed in a manner similar as that described with respect to FIG. 1. However, the embodiment of the invention shown in FIGS. 2 and 7 can be positioned so that one of the rocker plates, as for example rocker plate 240, is engaged by a bolt and the other rocker plate 240A, is adapted to be engaged by another locking component such as a latch. Thus, the unit is considered a double unit which will monitor the latch condition and also monitor the position of the accompanying deadbolt.
Thus, it will be seen that the latch monitor of the present invention is ideal for monitoring door latch or bolt condition and communicating that condition to a local or remote monitoring device, usually an alarm system. The device provides substantial advantages over prior art devices in that it is easily installed without the requirement of any field adjustment of the components, regardless of the vertical or lateral position of the associated latch or deadbolt. The rocker plate or plates occupy substantially the entire area within the strike for reliable monitoring. Because the switch is mounted on the side of the housing, maximum throw of the latch or deadbolt with respect to housing depth is permitted. No interfering components restrict the bolt or latch. Also, the rocker plate will be pivoted with minimum bolt throw so that the device accommodates a wide range of latch designs having latches of different shapes, sizes and throw.
The design utilizes a minimum of parts and is relatively easy to manufacture, assemble and install and is reliable and rugged in use. It will be appreciated that even if a locked door is rattled violently, the force will not be transmitted to the switch since the rocker plate is out of contact with the switch when the bolt is in place. Thus, the latch monitor of the present invention is universal and will work even with installations where the latch or bolt is relatively small as the generous extension of the flapper plate into the strike area will allow the flapper to be contacted even by smaller latches or bolts.
While the principles of the invention have been made clear in the illustrative embodiments set forth above, it will be obvious to those skilled in the art to make various modifications to the structure, arrangement, proportion, elements, materials and components used in the practice of the invention. Although described in connection with doors, the invention can be used with a wide variety of closures including, but not limited to gates, windows, doors and even closures such as machine guards. To the extent that these various modifications and applications do not depart from the spirit and scope of the appended claims, they are intended to be encompassed therein.
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A closure latch or bolt monitoring device having a housing mountable in a closure frame which housing receives a latch or bolt. A pivotal rocker plate is normally biased to a rest position in which a flange portion of the rocker engages a switch connectable to an alarm system. When a latch or bolt is extended into the housing, the rocker plate is pivoted causing it to disengage from the switch providing an indication to the alarm system that the bolt or latch is properly engaged in the closure. An alternate embodiment allows separate monitoring of two lock components such as a separate bolt and latch.
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TECHNICAL FIELD
This invention pertains to graphite or carbon and alkali metal compositions for the reversible storage of hydrogen gas and to methods for making such compositions.
BACKGROUND OF THE INVENTION
Hydrogen is a very energetic, clean burning fuel. It can be burned with great energy release in air or oxygen-enriched atmosphere to yield water without unburned hydrocarbons or carbon oxides as byproducts. The problem, of course, is that it is difficult to store hydrogen for mobile applications such as automobiles or trucks. Hydrogen can be stored as a liquid only if it can be kept very cold and under high pressure. If hydrogen is to be stored as a gas, most previous approaches have been to use metal containers suitable for confining the gas under very high pressures. There are no practical materials that can reversibly absorb or adsorb appreciable amounts of hydrogen at low pressure and give it up as a gas on demand. Accordingly, hydrogen has not been available as a practical fuel in vehicular applications.
There is a need to advance the art of hydrogen storage materials that can take up and temporarily hold substantial quantities of hydrogen at relatively low pressure and give up gaseous hydrogen on demand.
SUMMARY OF THE INVENTION
This invention provides a fully reacted alkali metal intercalated graphite or non-graphitic carbon that is capable of reversibly absorbing unusually large amounts of hydrogen gas. It is preferred to use graphite. One use of such material is as a temporary storage device for hydrogen fuel in connection with engines and fuel cells. Another use for the material is as a separation device to remove hydrogen from a mixture of gases.
One aspect of the invention is a method of forming a fully reacted alkali metal-graphite combination that has substantial hydrogen-adsorbing capabilities. The method suitably utilizes ordinary graphite or non-graphitic carbon and one or more alkali metals selected from the group consisting of lithium, sodium and potassium. Graphite, of course, is a crystalline form of carbon in which the carbon atoms lie in planes in C 6 hexagonal cells.
In accordance with the method, a mixture of six to 24 atomic parts of carbon (graphite) and one atomic part of alkali metal is formed. Due to the presence of the readily oxidized metal, the mixture is prepared under a substantially non-oxidizing atmosphere, suitably an argon atmosphere. The dry solid mixture is then vigorously compacted, for example in a die or mold, and heated to promote substantially complete intercalation of the alkali metal atoms between the graphene planes. When lithium is the alkali metal, it is preferred that the reactants be mixed in proportions of six to twelve atoms of carbon per atom of lithium. For sodium, the preferred ratio is eight to twelve carbon atoms per sodium atom, and for potassium the atomic ratio is eight to 24 carbon atoms. When mixtures of metals are used, the ratios are modified in proportion to the amounts of the respective metals.
In these proportions and under suitable conditions of pressure and temperature, the starting materials are fully altered to a binary intercalated structure. For example, an x-ray diffraction analysis of the product will normally contain none of the diffraction peaks of graphite or the alkali metal but will display a diffraction pattern characteristic of an alkali metal intercalated carbon composite suitable for the practice of this invention.
In a preferred embodiment of the invention, the graphite or non-graphitic carbon is pre-reacted with a small (less than specified amount) of the intended alkali metal. A precursor material is made using, for example, about 30 atomic parts of graphite per part of alkali metal. The precursor is suitably made using the same reaction conditions as for the final intercalated product. The formation of the precursor seems to initially exfoliate the graphite planes to better prepare the precursor for further intercalation with the alkali metal to achieve the specified composition for hydrogen storage.
The fully-reacted molded composite is usually initially in the form of a molded body. It can be used in the form of a molded body or comminuted to particles of a desired size. But a first surprising characteristic of the material is its capacity to take up hydrogen gas.
When a quantity of potassium-intercalated graphite is placed in a closed container with hydrogen gas at, e.g., 10 pounds per square inch gage (psig) and 150° C., the pressure in the vessel drops. If the amount of hydrogen is not sufficient to saturate the metal-graphite composite, the pressure falls below atmospheric pressure. The weight of the material increases, for example, by more than one-tenth to one-third of its original weight. The hydrogen absorption of the material is largely reversible.
Upon heating, a material with stored hydrogen releases hydrogen gas. Indeed, hydrogen intake or release can be cyclically induced by temperature or pressure change. In general, by decreasing the temperature or increasing hydrogen partial pressure, hydrogen absorption is increased. Conversely, by increasing temperature or decreasing hydrogen pressure, the hydrogen loading of the metal-graphite composite is decreased.
Obviously, the alkali metal-intercalated graphite material of this invention can be used to temporarily store hydrogen fuel for engines, fuel cells and the like. It can also be used in other hydrogen storage applications or in hydrogen separation applications.
There is an additional surprising feature of the binary material produced in accordance with this invention. It is found that when the lithium, sodium and/or potassium intercalated graphite of this invention is loaded with hydrogen, the resultant ternary material (of metal, graphite and hydrogen origin) has very interesting magnetic and electrical conductivity properties. By varying the hydrogen content of the ternary material, one “tunes” the electrical conductivity and magnetic properties as the material functions within the metal-insulator electron energy gap.
It is believed, without intending to limit the invention in any way, that the unexpected hydrogen storage capacity is related to nature of the electrons in the binary structure and resulting metal-graphite hydrogen ternary. The electrons are of mobile π character in the binary. As the hydrogen is absorbed, its valence electron partially escapes into the π electron environment. The effective volume of the hydrogen is decreased and the capacity of the binary composite for hydrogen is increased. Further, the combination of the hydrogen valence electrons with the π electrons of the binary contribute to the new electronic and magnetic properties of the metal-graphite-hydrogen ternary.
Other objects and advantages of this invention will become more apparent from a detailed description of preferred embodiments which follows. Reference will be had to the drawings that are described in the following section.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a graph of gage pressure, in pounds per square inch, versus time, in minutes, for a sample (Example 1) of a potassium intercalated graphite composition, KC 8 . The sample was contacted with a fixed amount of hydrogen, first at 150° C. and then at increasing temperatures to 300° C.
FIG. 2 is a thermogravimetric analysis (TGA) plot of the Example 1 sample in flowing hydrogen.
FIG. 3 is a thermogravimetric analysis (TGA) plot of the Example 3 sample in flowing hydrogen.
DESCRIPTION OF PREFERRED EMBODIMENTS
In this work, low cost graphite flakes or powder, graphite fibers and non-graphitic carbons have been used to prepare hydrogen-absorbing, carbon compounds. The process includes careful intercalation of alkali metals into a preconditioned graphite structure. The process developed in this work is applicable to most common graphitic materials and to non-graphitic carbons.
EXAMPLE 1
Preparation of Potassium Intercalated Graphite Samples
Twenty grams of graphite particulates with average particle size of five microns were mixed with two grams of elemental potassium and heat treated under argon atmosphere at 150° C. for eight hours under 5 tons/cm 2 pressure. The sample was cooled to ambient temperature and ground to fine powder. The mixture was heat treated for the second time at 150° C. for eight hours and cooled to ambient temperature.
The above sample was reacted with pure methanol in an inert environment. The methanol was added to the sample drop by drop until no gassing was observed. The sample was washed with excess methanol and filtered. This step removed any unreacted potassium from the partially potassium intercalated graphite material. The nominal composition of this precursor material was about KC 32+ . The partially intercalated precursor material was dried at 150° C. under vacuum (10 −3 torr) in argon atmosphere for eight hours. The sample was used for preparation of a hydrogen dense absorbing potassium-graphite composition.
Ten grams of the above potassium-graphite precursor material were used to make two compacted discs for further potassium intercalation. The discs were made at 5 tons/cm 2 pressure inside a dry box filled with argon. Four grams of potassium was sandwiched between the two potassium-graphite precursor discs and heat treated at 150° C. under 5 tons/cm 2 pressure in argon atmosphere for eight hours. The sample was cooled to ambient temperature and ground to fine powder. The powder was compacted under 5 tons/cm 2 and heat treated for a second time at 150° C. for eight hours. The sample was cooled to ambient temperature and stored for hydrogen uptake and release tests.
The composition of the final sample was determined to be close to KC 8 .
Pressure Test
1.5 grams of the above KC 8 , potassium intercalated graphite composition was placed inside a stainless steel bomb for hydrogen uptake—hydrogen release test. The volume of the stainless steel bomb was about 800 ml. The bomb was connected to a one-liter reservoir tank. After the sample was placed in the bomb under argon atmosphere, the bomb and the reservoir were evacuated to 10 −3 torr. The bomb and the reservoir then were pressurized with a fixed quantity of hydrogen to about 10 psig. The sample temperature was ramped to 150° C. and held at that temperature. The pressure of the reservoir tank was monitored as a function of time during heating and isotherm.
A continuous pressure drop from 10 psig was observed as a stable vacuum was developed. As shown in FIG. 1, the pressure steadily dropped over a period of ten to eleven minutes until the pressure of hydrogen in the system was a few pounds per square inch below atmospheric pressure. The potassium intercalated graphite sample had absorbed hydrogen from the bomb and reservoir creating a vacuum in the bomb-reservoir system. The temperature of the sample was then ramped to 300° C. As the temperature in the system increased, the sample released its hydrogen and the pressure increased to more than 15 psig. This cycle of hydrogen adsorption and desorption is reversible.
Thermogravimetric Test
Hydrogen uptake and release of the KC 8 , potassium intercalated graphite sample was measured quantitatively by thermogravimetric analysis. In this test, about 45 mg of the potassium intercalated graphite composition was loaded in a TGA system, which had been purged previously with argon. Then the sample was purged under continuous flow of hydrogen gas while its temperature was ramped to 300° C. at 10 degrees/min. The weight of the sample was monitored at 300° C. The test was continued as the temperature of the sample was cycled between 50° C. and 300° C. (at 10 degrees/min). The weight gain and weight loss of the sample vs. temperature is shown in FIG. 2 .
It is seen in FIG. 2 that the KC 8 sample weight increased steadily to a maximum value of about 117% of its original weight in the flowing hydrogen stream as the temperature first increased (curve 10 ) to about 280° C. The weight of the absorbed hydrogen then decreased as the temperature was further increased to 385° C. When the temperature was decreased at a rate of ten degrees per minute (curve 12 ), the weight of the sample plus hydrogen increased further to about 131% of the original sample weight at about 50° C. Upon heating again (curve 14 ), the sample released hydrogen to about 113% of the original sample weight. A second cooling (curve 16 ) and re-heating (curve 18 ) as well as a third cooling (curve 20 ) produced similar hydrogen storage and release cycles. Thus, it is seen that the potassium intercalated graphite sample of KC 8 composition repeatedly adsorbed up to about 33% of its weight of hydrogen and released about 20% of its weight of hydrogen in these heating and cooling cycles in flowing hydrogen at ambient pressure.
EXAMPLE 2
Preparation of Potassium Intercalated Carbon Samples
Twenty grams of graphite fiber (fiber diameter close to 1 micron) was mixed with 2 grams of potassium and heat treated at 150° C. for eight hours under 5 tons/cm 2 pressure. The sample was cooled to ambient temperature and ground to fine powder, and heat treated again at 150° C. for eight hours. This sample was cooled down to room temperature. Methanol was added to the sample until no further gassing was observed. The sample was rinsed with excess methanol, filtered and dried under vacuum (10 −3 torr) in argon atmosphere at 150° C. for eight hours.
The nominal composition of this precursor material was about KC 32+ . The sample was used for preparation of a hydrogen dense absorbing potassium-graphite composition.
From the precursor material two compacted discs, each weighing about five grams, were formed under 5 tons/cm 2 pressure. Four grams of potassium was sandwiched between the compacted discs under the same multi-ton pressure as above and heated under argon at 150° C. for eight hours. The sample was cooled to ambient temperature and ground to fine powder. The powder was heat treated for the second time under pressure at 150° C. for eight hours under argon gas.
The composition of the potassium intercalated carbon was KC 8 . After cooling the sample to ambient temperature, the sample was used for reversible hydrogen uptake and release tests with substantially the same results as presented in FIGS. 1 and 2 for the Example 1 material made from non-fibrous graphite.
EXAMPLE 3
A potassium intercalated graphite precursor material was prepared as described in Example 1.
Ten grams of the above potassium intercalated graphite precursor samples were used to make two compacted discs. Two grams of potassium were sandwiched between the two discs and reacted according to the procedure described in Example 1. At completion of the reaction process, the composition of this sample was close to KC 16 . The sample was kept under argon for hydrogen uptake-release tests.
The KC 16 composition was subjected to TGA under flowing hydrogen in an experiment like that described in Example 1. The temperature of the sample was slowly increased (10° C./min.) to 290° C. with a concomitant increase in sample weight (curve 30 ) to a maximum of more than 13% at about 205 degrees. This weight increase is attributable to a hydrogen uptake of that amount. A first cooling and heating cycle (curves 32 and 34 ) and second (curves 36 and 38 ) and third cooling and heating cycles (curves 40 and 42 ) again demonstrated the capability of this potassium intercalated graphite, KC 16 , to adsorb and release appreciable amounts of hydrogen gas. As seen, the sample adsorbed over 18% of its weight of hydrogen and released more than half of that hydrogen under the conditions of this example.
Additional general comments may be made about the above alkali metal intercalated graphite samples. The color of the samples ranged from dark copper to yellowish gold. At higher concentrations of potassium, the color was yellowish gold and at lower potassium concentrations the color becomes dark copper.
X-ray diffraction analyses showed single phase compounds when KC 8 was made. No diffraction lines of graphite or potassium were observed in the samples. However, when concentration of potassium was reduced from KC 8 to KC 16 , mixed phases of KC 8 and other phases of intercalated graphite material were formed.
Other interesting properties of the intercalated materials produced by the method aspect of this invention have been noted. The graphite material intercalated with potassium as produced in the above examples were shown to expel a magnetic field at temperatures above room temperature. In fact, the expulsion of the magnetic field was observed at 300° C. Samples with stored hydrogen experienced a weight loss when placed in a magnetic field. The observation of these phenomena suggest the presence of very interesting conductivity properties in the materials produced in accordance with this invention.
While the above examples have illustrated the practice of the invention with potassium intercalated graphite compositions, the invention may likewise be practiced using lithium or sodium as the alkali metal ingredient. Further, mixtures of the metals may be used. As stated above, when lithium is the alkali metal, it is preferred that the reactants be mixed in proportions of six to twelve atoms of carbon per atom of lithium. For sodium the preferred ratio is eight to twelve carbon atoms per sodium atom and for potassium the atomic ratio is eight to 24 carbon atoms. When mixtures of metals are used, the ratios are modified in proportion to the amounts of the respective metals.
Useful hydrogen storage compositions may be made by a one-step intercalation of the carbon with the alkali metal to the preferred atomic proportions. However, it is much preferred to first prepare a graphite-rich composition that has been intercalated with a relatively small amount of the alkali metal as demonstrated in the above specific illustrative examples. Precursors with a carbon-to-alkali metal atomic ratio of about 30 or higher provide a starting material that yields excellent hydrogen storage compositions upon further intercalation.
Also, as stated above, suitable non-graphitic carbons may be employed to make useful hydrogen storage compositions, but graphitic carbons are preferred.
While the invention has been described with reference to preferred embodiments, other forms of the invention could readily be adapted by those skilled in the art. Accordingly, the invention is to be considered limited only by the scope of the following claims.
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A hydrogen fuel storage composition is prepared by mixing and reacting, on an atomic proportion basis, one part of an alkali metal selected form the group of lithium, sodium or potassium with eight to 24 parts of carbon under conditions of temperature and pressure such that a fully-reacted alkali metal intercalated graphitic carbon composite is formed. When suitably prepared, such a composite can reversibly absorb ten percent or more of its weight of hydrogen gas.
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BACKGROUND OF THE INVENTION
[0001] All-terrain vehicles or ATV's are versatile all-season three or four-wheeled motorized vehicles designed for off-road use, including pedestrian and bicycle pathways. Typically ATV's are straddle-type vehicles, where the operator straddles the seat similar to a motorcycle or bicycle. They are generally designed to carry one or two passengers. Although primarily a recreational vehicle, more recently ATV's have been used as utility vehicles. To that end, various utilitarian accessories or implements, such as snow plow blades, can be attached to the ATV. Although the relatively light weight of the ATV allows for the use of small engines, the small engines limit the power capabilities; ATV's generally have a battery and battery recharging system having low amperage storage and low amperage recharging capability relative to a typically automobile. The term “all terrain vehicle” or “ATV” as used herein includes within its scope so-called utility task vehicles or “UTV's”, such as the Kawasaki MULE, the John Deere GATOR, the Polaris RANGER and PROFESSIONAL SERIES, the EZ-GO WORKHORSE, the Club Car CARRYALL and PIONEER and the Toro WORKMAN.
[0002] Conventional snow blade mounts for four wheel drive vehicles such as pick-up trucks can weigh hundreds pounds (e.g., 750 pounds), and generally include a chassis frame that can be permanently fixed to the vehicle chassis, usually behind the vehicle front bumper. A lift frame is then removably coupled to the chassis frame, and the snow blade is then coupled to the front end of the assembly via an A-frame and trip frame assembly. The A-frame with the snow blade attached is typically removable from the vehicle. Such assemblies, however, are too large and too heavy for practical use with the relatively small ATV.
[0003] One drawback of conventional snow blade mounts is the difficulty in readily removing the assemblies from the vehicle chassis, especially in view of their weight. The presence of an implement or accessory on an ATV can render the ATV useless as a recreational all-terrain vehicle. Accordingly, it is highly desirable that the blade be removed after use. However, since the mounting and dismounting operation can be cumbersome and time-consuming, the assemblies are often left on the ATV for the entire winter season.
[0004] It is therefore an object of the present invention to provide a utilitarian accessory mounting assembly for an ATV that is conveniently and easily attachable and removable from the vehicle.
[0005] It is a further object of the present invention to provide a snow blade assembly for an ATV that is mounted and dismounted from the vehicle using a self-aligning hitch mount devoid of mounting pins.
[0006] It is a still further object of the present invention to pivot the utilitarian accessory remotely.
SUMMARY OF THE INVENTION
[0007] The problems of the prior art have been overcome by the present invention, which provides a hitch mount assembly for snow blades or other accessories or implements for off-road vehicles such as all-terrain vehicles. The present invention includes an implement assembly readily removably coupled to the vehicle, such as in conjunction with a receiver that is mounted to the vehicle chassis or frame or is integrated therewith. The configuration of the receiver and implement assembly allows for self-alignment during the mounting operation. A switching mechanism and actuator also can be used to pivot the working implement remotely.
[0008] In one embodiment, a power winch is used to mount the assembly to the ATV. The winch is also used to vertically raise and lower the working implement relative to the ground. In another embodiment, the relatively light-weight of the assembly allows the assembly to be mounted to the ATV manually, without the use of a winch or other power-operated tool, simply by pushing the assembly towards the ATV or by driving the ATV towards the assembly.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] [0009]FIG. 1 is a perspective exploded view of a snow blade mounting assembly in accordance with the present invention;
[0010] [0010]FIG. 2 is a perspective view of a receiver in accordance with the present invention;
[0011] [0011]FIG. 2A is a perspective view of a receiver in accordance with another embodiment of the present invention;
[0012] [0012]FIG. 3 is a front view of the receiver of FIG. 2 shown mounted to the chassis of an ATV;
[0013] [0013]FIG. 4 is a perspective view of a snow blade mounting assembly shown partially mounted to an ATV in accordance with the present invention;
[0014] [0014]FIG. 5 is a perspective view of the blade pivoting mechanism in accordance with the present invention;
[0015] [0015]FIG. 6 is a perspective view of a portion of the mounting assembly in accordance with the present invention;
[0016] [0016]FIG. 6A is a view of a lift handle for manual actuation of a blade;
[0017] [0017]FIG. 7 is a perspective view of a portion of the mounting assembly in accordance with the present invention;
[0018] [0018]FIG. 8 is a perspective bottom view of the blade shown attached to the A-frame in accordance with the present invention;
[0019] [0019]FIG. 9 is a perspective view of the accessory actuator in accordance with the present invention;
[0020] [0020]FIG. 10 is a perspective view of the motor for pivoting the accessory in accordance with the present invention;
[0021] [0021]FIG. 11 is a partial perspective view of the spool and cable assembly in accordance with the present invention;
[0022] [0022]FIG. 12 is a schematic diagram of the switching system in accordance with the present invention; and
[0023] [0023]FIG. 13 is a perspective view of a portion of the mounting assembly in accordance with another embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0024] Turning first to FIG. 1, there is shown generally at 10 the blade and hitch assembly in accordance with a preferred embodiment of the present invention. The assembly 10 is relatively lightweight, preferably weighing between about 50 and about 300 pounds, and is most preferably sufficiently light to enable a single individual to slidingly push the assembly into mounting engagement with the receiver on the vehicle. Thus, its various components can be constructed of metal, steel, stainless steel, plastics or composites, for example, depending upon the relative strength required of each component. Vehicle mounted receiver 11 attaches to the vehicle chassis or frame, or is integrated therewith. Any suitable means can be used to secure the receiver 11 to the vehicle, such as bolting or manufacturing integration (e.g., as a stamped component of the vehicle chassis or frame) For example, as shown in FIG. 2, the receiver 11 can include a pair of U-shaped flanges 8 with holes for coupling the receiver to the vehicle chassis. The design of the receiver 11 interface for attachment to the chassis will depend upon the identity (and thus design) of the particular chassis, and is well within the skill in the art. Because in the embodiment shown the receiver 11 is situated under the chassis and is not obtrusive, it optionally can be permanently affixed to the chassis, regardless of whether the snow plow blade or other accessories or working implements are attached or in use. Alternatively, the receiver can be located on the vehicle frame where it does not extend below the frame so as to provide adequate ground clearance. It is fixed and preferably has no moving parts; its main purpose being to provide a means of attachment of the follow-on components. It also can absorb and transfer any shock loads imposed on the snow blade (or other accessory) into the vehicle. It can be made of any rigid material suitable for the job, such as steel, metal, stainless steel, plastic or composites, for example.
[0025] As best seen in FIGS. 2 and 3, the receiver 11 is preferably trapezoidal in shape, uniformly tapering inwardly from its open front end towards the rear. It has an optional top plate 6 , with opposite vertically depending side guides 7 a and 7 b as shown. Alternatively, the sides 7 a and 7 b could be independently attached directly to the chassis, directly to the frame, or integrated therewith, preferably defining between them a trapezoidal wedge. A front upwardly angled lip 9 is optionally provided at the receiver entry to assist in guiding the implement to be mounted into the receiver 11 , in the direction of the arrows shown in FIGS. 2 and 3. The sides 7 a , 7 b are in a tapered profile such that the distance between them decreases in the direction towards the vehicle rear when mounted thereto.
[0026] Turning back to FIG. 1, the blade and hitch assembly 10 is adapted to be releasably coupled to or engaged by the receiver 11 . In the embodiment shown, a blade 15 is illustrated as the utilitarian accessory or working implement, although those skilled in the art will appreciate that the present invention is not limited to mounting and dismounting of a blade. The blade 15 can be conventional in design. The preferred blade is made of sheet metal, or is a sheet of steel bumped or rolled to a semi-round shape. The blade 15 also can be in the form of an adjustable V-shaped blade. The blade is braced on the backside with a plurality of mounts 4 providing a means of attachment (such as via springs 3 ) to the support frame 20 .
[0027] As best seen in FIGS. 7 and 8, support frame 20 includes opposite side members 21 a , 21 b that preferably are bent along their lengths to define an A-frame portion 22 . The A-frame portion tapers towards an apex that can be pivotably coupled directly to the blade 15 , or is attached to the blade 15 through a trip flame assembly as discussed in greater detail below. Those skilled in the art will appreciate that although the term “A-frame” is used herein, the frame need not be in the shape of an “A”. Male hitch member 25 is coupled to a pivotable cross bar 26 (such as by welding to ears 97 ) that is pivotably supported between opposite sides 21 a , 21 b . At least a portion of the hitch member 25 corresponds in shape to receiver 11 , so that that portion of the hitch member 25 can be slidingly engaged by receiver 11 during the mounting operation. Thus, in the preferred embodiment, hitch member 25 has a trapezoidal portion, which tapers outwardly from the free end 25 a in the direction towards the implement 15 . In the embodiment shown, the taper extends to a maximum and then tapers inwardly to the opposite end of the member 25 . Those skilled in the art will appreciate that the free end of the hitch member 25 can be formed as two or more extensions rather than a single continuous end as shown. The hitch member 25 and cross bar 26 pivot about a horizontal axis, preferably about 200 from horizontal in each direction.
[0028] Turning now to FIG. 4, an optional trip frame assembly is shown that includes half-ring or A-frame retainer 36 supported on the top surface of the A-frame 22 . Those skilled in the art will appreciate that the half-ring 36 can be designed having shapes other than that shown. The trip frame assembly is connected to the blade 15 via springs 3 (two shown). The trip frame assembly allows the blade 15 to pivot forward, which allows it to trip over obstacles and absorb shock that would otherwise be transferred into the plow frame assembly and vehicle, which in extreme cases would cause substantial damage. If the trip frame assembly is eliminated, the blade can have a conventional trip edge as known in the art.
[0029] Extending from the half-ring or retainer 36 is a notched plate 37 , also supported on the A-frame 22 top surface, to set the blade angle. The plate 37 has a plurality of spaced notches 38 extending around the annular edge of the plate 37 as shown. As the blade 15 pivots, the notched plate 37 also pivots, and can be locked in place with locking mechanism 40 that, when properly aligned with a notch 38 , inserts into that notch 38 to prevent movement of the plate (and thus the blade 15 ) until it is retracted from the notch.
[0030] One suitable mechanism for actuating the locking mechanism uses cable 41 extending from the locking mechanism 40 to a location where it is readily accessible by the driver of the ATV. By tensioning the cable 41 by drawing it towards the vehicle rear, such as with remote control actuator 71 (FIG. 9), the locking mechanism is disengaged from the notch 38 , allowing the blade to pivot. More specifically, actuator 71 is slidably mounted in cable bracket 72 as is conventional in the art. By pulling actuator towards the vehicle rear, in the direction of arrow 73 , the cable 41 is tensioned and the locking mechanism is unlocked, allowing the blade 15 to freely pivot. Once the blade 15 is positioned as desired, the tension on the cable 41 is released by releasing the actuator 71 , allowing the locking mechanism to again latch into a notch 38 and lock the blade in place. Those skilled in the art will appreciate that the locking mechanism can be operated manually.
[0031] Proper angling of the blade 15 , when the blade is in a freely pivotable position, was conventionally accomplished manually, requiring the operator to leave the vehicle and physically pivot the blade. Alternatively, the operator would drive the blade into a stationary object, such as a tree, to pivot the blade. Either method was tedious and inconvenient. In accordance with one embodiment of the present invention, the blade angle preferably is controlled remotely, such as by the driver of the ATV when seated on the ATV in the driving position. Thus, the remote actuator 71 can be used not only to unlock the blade 15 as discussed above, but also to remotely pivot the blade. To that end, remote actuator 71 is modified with slotted member 77 that receives switch 76 in slot 78 . Switch 76 , such as rocker or toggle switch, is in electrical communication with a bi-directional motor 80 (FIGS. 4 and 10). It is preferably a double pole, double throw three-position switch, the center being the off position and the other two positions being momentary (FIG. 12 shows a suitable schematic of the switch). The motor 80 is preferably powered by the vehicle battery 90 and reversibly drives drum or spool 81 (FIG. 11) wrapped with two separate cables; one threaded through pulley 82 a and secured at or near an end of the blade 15 , and the other threaded through pulley 82 b and secured at or near the other end of blade 15 . The attachment of each cable to the blade 15 can be a direct attachment, or a spring 84 (FIG. 8) can be positioned between the blade and the cable for added play.
[0032] To pivot the blade 15 , the operator draws actuator 71 in the direction of arrow 73 to unlock the blade. The actuator is then rotated to the left or to the right, depending upon the desired angle of the blade, thereby actuating switch 76 which engages the motor 80 , driving spool 81 . When driven in one direction, the spool 81 deploys one cable and reels in the other, and when driven in the other direction, the opposite cables are deployed from and reeled onto the spool, respectively. The deploying or reeling in of cable pivots the blade accordingly. Once the blade is in the desired position, the actuator is rotated back to the normal position, which corresponds to the center position of the switch 78 , and is then released to lock the blade in place. Those skilled in the art will appreciate that the actuator for power angling of the blade need not be the same actuator used to unlock the blade from its fixed position; separate actuators can be used to accomplish these operations.
[0033] Further details will now be provided regarding the hitch mount of the present invention. As discussed above, receiver 11 , preferably made of ⅜″ mild steel, is attached to the vehicle by suitable means or is integrated therewith such as during manufacturing of the vehicle. Conveniently, some conventional ATV's come equipped with a round bar or rod 200 , solid or tubular, and generally about ⅜ to ½″ in diameter, secured to the vehicle front (FIG. 1). In the embodiment shown in FIGS. 4 and 7, the bar 200 extends horizontally a distance sufficient to be engaged at or near its opposite ends by one or more latch hooks 220 discussed in detail below. Those skilled in the art will appreciate that the bar 200 could be vertical or angled, and need not be continuous; two or more separate bars could be used such as at each end of the receiver 11 (FIG. 2A), as long as they are appropriately positioned for engagement by one or more latch hooks 220 . In addition, the bar need not be round; other shapes corresponding to the receiving shape of the latch hook could be used. Preferably the bar or bars are located above the plane of the receiver 11 . The receiver 11 need not be positioned directly under the bar or bars; the bar or bars could be positioned radially outwardly of the receiver 11 such as shown in FIG. 2A.
[0034] In ATV's where the rod 200 is not original equipment, it can be added. For example, as shown in FIG. 2A, the bar 200 can be part of the receiver 11 , as one continuous bar or as two or more separate bars. Again, the bar(s) could be vertical or angled with respect to horizontal, and need not be positioned directly over the receiver 11 . Where two or more separate bars are used, they are preferably positioned in the same plane. In the embodiment of FIG. 2A, there are two bars that each terminate in opposite free ends.
[0035] Receiver 11 includes generally longitudinally extending (in the direction from the vehicle front to the vehicle rear) side guide members 7 a , 7 b as discussed above, which help ensure proper alignment of the hitch assembly. The spacing or volume or distance between these guide members is configured to accommodate the male hitch 25 pivotably coupled to the frame 20 . Thus, in the embodiment shown, the hitch member 25 is tapered such that the length of its free engaging end 25 a is relatively short, and expands in the direction towards the implement 15 . Similarly, sides 7 a , 7 b are configured and placed such that the receiver volume is tapered, with its end farthest from the vehicle front being shorter than the end closest to the vehicle front. The sides 7 a , 7 b thus act as a track for receiving and aligning hitch member 25 . Free end 25 a of hitch member 25 can be formed with a notch 15 a (FIG. 1) to ensure that the hitch member 25 clears the nut and bolt that attaches the receiver 11 to the vehicle chassis. Those skilled in the art will appreciate that two or more receivers 11 can be used, in which case two or more hitch members would be used.
[0036] Pivotally coupled to spaced side brackets 54 , 55 via a pivot shaft is a latch 220 , which in the embodiment shown, is centrally located on cross bar 23 (FIG. 6). The side brackets 54 , 55 are spaced a sufficient distance to accommodate the latch 220 and allow for its movement. Although only one latch 220 is necessary, multiple latches could be used and are within the scope of the present invention. One such embodiment is illustrated in FIG. 13, where two opposite and aligned latches 220 A, 220 B are shown. Where multiple latches are used, the latches 220 can share a common pivot shaft, the pivot shaft extending from one latch to the other so that movement of the latches is coordinated; actuation of one latch results in a corresponding movement of the other latches. Alternatively, the multiple latches can be actuated separately.
[0037] Each latch 220 preferably has a hook shape including an arcuate recess 225 corresponding in angle to the circumference of the bar 200 . The latch is thereby adapted to receive bar 200 . Preferably the recess is shaped as a concentric cam, so that upon contact with the bar 200 , the latch 220 can automatically pivot to a closed position, locking onto the bar 200 . This design facilitates the grasping and interlocking of bar 200 as well as the dismounting operation. The latch 220 can include a handle 221 for manual actuation for use such as in the event the latch does not properly lock onto the bar 200 . A latch locking assembly 230 (FIG. 1) optionally can be used to lock the latch in place. One suitable locking assembly includes a spring loaded pin assembly, with spring biasing against a pin 241 . In the locked position, the spring forces pin 241 through an appropriately dimensioned aperture in the latch, thereby fixing the latch 220 in place. Lever 243 , shown in FIG. 4 in the locked (orthagonal) position, prevents pin 241 from retracting out of the aperture. In the unlocked position, the pin is retracted from the aperture, allowing movement of the latch for engagement or disengagement of the hitch.
[0038] The preferred method for attaching the hitch mounting assembly to the ATV will now be described with particular reference to FIG. 4. The vehicle 100 is positioned close to the hitch mounting assembly, and one end of a tether 70 , such as a rope, chain, cable, wire, links, etc., is attached to the vehicle 100 preferably at a location higher (to later facilitate lifting of the blade) than the mounting assembly. Most ATV's come equipped with a utility hook or clamp 71 coupled to a rope permanently attached at or near the top of the ATV body. This or any other convenient location typically at or near the front of the ATV can be used as the point of attachment of one end of the tether 70 . In ATV's where the clamp 71 is not original equipment, it can be added or another point of attachment can be used. The tether 70 is also attached to an actuator 75 such as a winch mounted on the mounting assembly, such as on the A-frame or on the working implement itself. In the embodiment shown, the winch 75 is electrically driven by the motor of the ATV, although it is within the scope of the present invention for the which to be powered separately. Actuation of the winch causes the tether to be reeled onto the spool of the winch, in turn causing the mounting assembly to be pulled towards the vehicle 100 . The free end of the hitch member 25 is thus pulled towards receiver 11 in the direction of arrow 90 . In view of the corresponding shapes of the receiver 11 and hitch member 25 , the mounting assembly properly aligns with the vehicle 100 as the hitch member 25 is engaged by the receiver 11 . As the tether continues to wrap around winch 75 and pull the mounting assembly towards the vehicle, the hitch member 25 continues to progress into receiver 11 , until latch 220 engages bar 200 . The engagement of the latch with the bar causes the latch to pivot into a closed position about the bar. The locking assembly is then actuated (either automatically, or manually via lever 243 ) to secure the latch in place. Continued actuation of the winch raises the blade, and thus the winch can be used during operation of the vehicle to raise and lower the blade. Alternatively, the blade can be raised and lowered in a conventional manner, such as manually with a lift handle 210 (FIG. 6A) positioned rearwardly of the blade, the lift handle 210 being pivotally mounted on a bracket 212 and connected to a bell crank to vertically lift or lower the blade. Such manual actuation of the blade is disclosed in U.S. Pat. No. 5,615,745, the disclosure of which is hereby incorporated by reference. In the embodiment shown, in the latched position the recess of the latch 220 faces downwardly towards the ground, although the latch 220 can be designed so that the recess faces upwardly.
[0039] Alternatively, the assembly can be mounted to the vehicle manually. In view of the design of the hitch member 25 and corresponding receiver 11 and the relatively light weight of the hitch assembly, the assembly can be simply “pushed” into mounting relationship by one or more individuals without the use of the winch. For example, an individual can stand in front of the working implement, place his hands on the implement, and slide the assembly 10 towards the receiver 11 , allowing the hitch member to enter the receiver 11 and progress towards the rear thereof until the latch or latches engages bar or bars 200 .
[0040] To remove the hitch mounting assembly from the vehicle chassis, the locking pin is released, and the lever 221 optionally is placed in the down position. Upon separating the vehicle from the assembly (such as by driving the vehicle away from the assembly or by manually pulling the assembly away from the vehicle), the latch moves away from the bar 200 , disengaging the same and actually pushing the receiver 11 away from the assembly. The electrical and mechanical connections are then disconnected to complete the dismount.
[0041] Alternatively still, the assembly can be mounted to the vehicle by driving the vehicle towards the assembly, and in particular, towards the free end of the hitch member 25 so that it can be received by the receiver 11 . As the mounting progresses, the latch or latches engage the bar 200 and are locked in place. To facilitate the mounting and minimize or prevent the assembly from moving away from the vehicle as it is engaged by the receiver, the assembly can be temporarily fixed in place, such as by positioning it in front of an obstruction.
[0042] Those skilled in the art will appreciate that although the foregoing illustrates a front-mounted assembly, mounting the same to the rear of the vehicle is within the scope of the present invention.
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Hitch mount assembly for snow blades or other accessories or implements for off-road vehicles such as all-terrain vehicles. The assembly includes a receiver for mounting to the vehicle chassis and an implement assembly readily removably coupled to the receiver. The configuration of the receiver and implement assembly allows for self-alignment during the mounting operation. A switching mechanism and actuator also can be used to pivot the working implement remotely. The mount assembly can be attached to the vehicle with a powered winch or manually.
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FIELD OF THE INVENTION
The present invention is directed generally to a joist protector. More particularly, the present invention is directed to an extruded plastic or rubber joist protector. Most specifically, the present invention is directed to a plastic joist protector having water deflectors and decking spacers. The plastic joist protector is useable primarily with exterior construction, such as wooden decks, patios and the like. The protector is placed atop the wooden joists and beneath the deck planking to form a barrier which prevents entry of water into nail holes or cracks in the joists to thereby significantly extend the life of these joists.
DESCRIPTION OF THE PRIOR ART
Wooden decks and patios have enjoyed increasing popularity in recent years as an adjunct to homes and in various municipal parks, recreational areas and the like. Additionally, there has been a trend to the inclusion of porches on recently constructed homes. Further, the utilization of elevated wooden bicycle paths, nature trails and other similar exterior wooden structures has also increased markedly in recent years. These wooden exterior structures are typically constructed using either untreated lumber, which may subsequently be painted or stained, or using so-called pressure treated or salt treated materials.
In the course of time in wooden deck and similar construction which is exposed to the elements, water enters the joints through nail holes and starts to rot the wood. Even in pressure treated joists, the treating material often does not permeate throughout the wood so that water which enters into the core of the joists will start the process of rotting which, in time will cause the nails used to secure the deck planking in place to lose their grip. Eventually, this water damage may lead to the complete deterioration of the joists so that it will have to be replaced.
Exterior decks and patios as well as walkways and raised bridges are frequently constructed with the deck plankings being spaced slightly apart from each other. This provides an open appearance which is quite popular and which also allows rain water, melting snow and the like to run off the deck and away through these spaces. Frequently during construction of the deck, the spacing of the deck planks is done by eye or by using a crude spacing scheme, such as by spacing adjacent planks the width of a nail shank. This clearly results in non-uniform spacing which is apt to reduce the overall appearance of the structure.
It will thus be seen that there is a need for a joist protector which will overcome the problems inherent with typical construction procedures, as discussed above. The joist protector in accordance with the present invention provides such a device and is a significant advance in the art.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a joist protector.
Another object of the present invention is to provide a plastic joist protector.
A further object of the present invention is to provide a joist protector which has integral deck planking spacers.
Yet another object of the present invention is to provide a joist protector having spaced water deflectors.
Even a further object of the present invention is to provide a joist protector having a central nailing strip.
Still yet another object of the present invention is to provide an extruded plastic joist protector.
As will be discussed in greater detail in the description of the preferred embodiments which is set forth subsequently, the joist protector of the present invention is useable to shield the upper surface of wooden joists and to prevent water from entering the joist through nail holes, cracks and the like. The joist protector is made of one or more plastic compositions which may be extruded or otherwise formed in various lengths. The joist protector includes a generally planar central web with opposed, downwardly inclined side flanges. A plurality of raised water deflectors may extend transversely across the upper surface of the joist protector as may suitably spaced planking spacers. The joist protector may be extruded of a single plastic material or may be formed having a central, more flexible nailing strip which is co-extruded with spaced, more rigid plastic side portions.
The joist protector of the present invention is used by placing it atop the joists before the dect planks are put down. The two side flanges slope outwardly and downwardly while the planar central web overlies the upper surface of the joist. The deck planks are then put in place and are nailed down in a conventional manner. Since the joist protector is made using a resilient material such as plastic, the nails will pass through the protector and into the joist. In the embodiment which uses a central nailing strip in the planar web of the joist protector, there may be used a plastic material which will essentially be self-sealing to even more fully prevent entry of water into nail holes in the joists.
The joist protector of the present invention may be formed having suitably spaced deck planking spacers which are generally parallel to the water deflector and which may be spaced in accordance with popular deck planking widths. These deck planking spacers extend up from the upper surface of the generally planar central web of the joist protector. These serve as an accurate spacing system so that the deck planks will be uniformly and consistently spaced as the deck or the like is being built.
The joist protector in accordance with the present invention may be molded from a variety of plastics which are well suited for outdoor useage. These plastics may have a colorant added which will match or complement the natural color of the wood or various paints and deck stains. The joist protector in accordance with the present invention provides deck joist protection, is easy to use, and can be installed quickly during construction. As will be appreciated, it is a substantial advance in the art.
BRIEF DESCRIPTION OF THE DRAWINGS
While the novel feature of the joist protector in accordance with the present invention are set forth with particularlity in the appended claims, a full and complete understanding of the invention may be had by referring to the detailed description of preferred embodiments, as is set forth subsequently, and as illustrated in the accompanying drawings, in which:
FIG. 1 is a perspective view of a first preferred embodiment of a joist protector in accordance with the present invention and showing the joist protector in use;
FIG. 2 is a perspective view of a second preferred embodiment of the joist protector in place atop a joist;
FIG. 3 is a sectional side elevation view of the joist protector taken along line III--III of FIG. 2;
FIG. 4 is an enlarged sectional view of a portion of the joist protector and showing the water deflectors; and
FIG. 5 is an enlarged sectional view of another portion of the joist protector and showing the deck planking spacers.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring initially to FIG. 1, there is shown, generally at 10, a first preferred embodiment of a joist protector in accordance with the present invention. Joist protector 10 is depicted in a use position atop a deck joist, generally at 12 to which is being secured one of what will be understood by those of skill in the art a number of decking planks, generally at 14. While the joist portector of the present invention will be discussed hereinafter in conjunction with a deck, it will be understood that its useage is not limited solely to decks. The joist protector of the present invention is useable in any construction in which wooden members are nailed, bolted, or screwed to underlying joists.
As may be seen in FIG. 1, joist protector 10 has a generally planar central web 16 which is bounded by opposed, downwardly inclined side flanges 18. In the first preferred embodiment depicted in FIG. 1, joist protector 10 is fabricated from a somewhat rigid, yet resilient material such as polyvinyl chloride or a rubber having an ultraviolet stabilizer for long life in outdoor conditions. While the material is adequately rigid to provide the side flanges 18 with sufficient stiffness so that they do not sag down onto the sides of joist 12, it will be understood that the material will not split or splinter as a nail 20 is driven through it to secure deck plank 14 to joist 12.
Planar central web 16 of joist protector 10 may have; as is depicted schematically in FIG. 1, and as may be seen more clearly in FIGS. 3-5, a plurality of transversely extending water deflectors 22 and interspersed deck planking spacers 24 which are formed on an upper surface 26 of central web 16. These will be discussed in detail shortly. The width of central web portion 16 is selected to be slightly greater than that of the width of joist 12 with which the joist protector will be used. For example, with a joist having a normal 2 inch width, or an actual width of 15/8 inch, the width of planar web 16 will be generally about 17/8 inch. The length of joist protector 10 can be one of several convenient lengths to match typical joist lengths, i.e., 8, 10, or 12 feet. Joist protector 10 is easily cut to length by using conventional tools. The thickness of joist protector 10 may be generally about 0.080 inch.
Side flanges 18 of joist protector 10 are formed coextensively with central web 16 and, in the preferred embodiments, are inclined downwardly from the horizontal at an angle of generally about 30°. As discussed above, the material selected for joist protector 10 has sufficient rigidity so that these side flanges will stand away from the sides 30 of joist 12. Thus any water which runs off the central web 26 of joist protector 10 will not run down the joist sides 30. The side webs 18 increase the overall width of joist protector 10 to generally about 27/8 inch for a nominally 2 inch joist. It will again be understood that these dimensions are somewhat exemplary and will vary with the width of joist 10.
A second preferred embodiment, generally at 40, of the joist protector in accordance with the present invention is depicted in FIG. 2. Both first and second embodiments 10 and 40 are similar in overall shape and useage and similar numerals are used in both drawings for corresponding parts, where appropriate. While the central web 16 of first joist protector 10 is formed of a single material, the central web 42 of second preferred embodiment 10 has a center nailing strip 44 which extends the length of central web 42 and which, in the preferred embodiment, has a width of generally about 1 inch. This second preferred embodiment 40 can be formed by co-extruding two polyvinyl chlorides of differing hardness. The center nailing strip 44 is the softer of the two and is effectively self-sealing around nails 20 which pass through it into the joist 12. The balance of the central web 40 and the opposed side flanges 18 have sufficient rigidity to prevent the side flanges 10 from sagging down onto the sides 30 of joist 12. Central web 42 of second preferred embodiment 40 of the joist protector may also be provided with transverse water deflectors 22 and deck planking spacers 24 in a manner similar to first preferred embodiment 10.
Turning now primarily to FIGS. 3-5, the structure and function of water deflectors 22 and deck planking spacers 24 will be discussed in detail. It will be understood that the deflectors 22 and spacers 24 are equally useable with either first or second preferred embodiments 10 or 40 and that the discussion hereinafter is appropriate for both. Water deflectors 22, as seen most clearly in FIG. 4 are generally triangular in shape and have upwardly inclined side walls 50 which are inclined at an angle of generally about 45 to the horizontal. These water deflectors extend upwardly about 0.010 inch above the surface the central web and are spaced generally about 1/8 inch apart. It will be understood that in use, these water deflectors 22 form parallel water channels 52 which channel water out to the edges of the central planar web 16 or 42 so that it will flow down the side flanges 18.
Deck planking spacers 24, as may be seen in FIG. 3 are generally parallel to water deflectors 22 and also extend transversely across the central web 16 or 42. These deck planking spacers 24 may be seen most clearly in FIG. 5 and have generally vertical side walls 54 and a generally planar top surface 56. These side walls 54 have heights of generally about 0.030 inch, which is also the width of planar top surface 56. As will be readily apparent, the longitudinal spacing of these deck planking spacers 24 will be one of several standard widths of conventionally used decking plank 14. As discussed above, the purpose of these deck planking spacers 24 is to provide a guide so that planks 14 nailed or otherwise secured to spaced joists 12 will be uniformly spaced.
In use during the construction of a deck, patio or other wooden structure, the joists 12 are placed in any conventional manner. The joist protector of either embodiment 10 or 40 is then placed on the upper surface of each joist and is cut as needed to be generally the same length as the joist. Now the deck planks 14 are put in place on top of the joist protector 10 or 40 with the deck spacers 24 serving to accurately and uniformly space the planks 14. As the planks 14 are put down, they are secured in place by suitable fasteners, such as nails 20. These fasteners pass through the central web of the joist protector, and in the second embodiment 40 through the center nailing strip 44. In either instance, the nail 20 does not split or break the joist protector which thus acts to prevent ingress of water into the nail hole formed in joist 12 by nails 20. Any water which contacts the joist protector will be directed by water deflectors 22 into the water channels 52 and will run off so it does not stand on the joists 12.
The joist protector in accordance with either of the preferred embodiments of the present invention prolongs deck life at a small cost. It is easily put in place during construction, requires no additional tools or equipment, and will not itself rot or deteriorate. It can be colored to match the wood and is very unobtrusive in use. While two preferred embodiment of the joist protector in accordance with the present invention have been fully and completely set forth hereinabove, it will be apparent to one of skill in the art various changes in, for example the specific type of plastic materials used, the particular lengths of the strips, and the like could be made without departing from the true spirit and scope of the invention which is accordingly to be limited only by the following claims.
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A joist protector which is placeable between a joist and a plurality of planks prevents water from entering the joist through nail holes or cracks. The joist protector has a generally planar central web and downwardly angled side flanges. A plurality of spaced water deflectors and interspersed deck planking spacers may be formed on the central web.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention is directed to a novel cement composition for the preparation of a novel aqueous slurry useful in cementing casing in the borehole of a well comprising (1) cement, (2) (a) a hydroxyethylcellulose ether having a critical viscosity or (2) (b) a mixture of a hydroxyethylcellulose ether having a critical viscosity and of a hydroxypropylcellulose ether having a critical viscosity and (3) a dispersant.
2. Description of the Prior Art
After a borehole of an oil or gas well has been drilled, casing is run into the well and is cemented in place by filling the annulus between the borehole wall and the outside of the casing with a cement slurry, which is then permitted to set. The resulting cement provides a sheath surrounding the casing that prevents, or inhibits, communication between the various formations penetrated by the well. In addition to isolating oil, gas and water-producing zones, cement also aids in (1) bonding and supporting the casing, (2) protecting the casing from corrosion, (3) preventing blowouts by quickly forming a seal, (4) protecting the casing from shock loads in drilling deeper and (5) sealing off zones of lost circulation. The usual method of cementing a well is to pump a cement slurry downwardly through the casing, outwardly through the lower end of the casing and then upwardly into the annulus surrounding the casing. The upward displacement of the cement slurry through the annulus can continue until some of the cement slurry returns to the well surface, but in any event will continue past the formations to be isolated.
If the primary cementing of the casing, as described above, does not effectively isolate the formations, it may become necessary to perforate the casing at intervals along its length and then squeeze a cement slurry under high pressure through the perforations and into the defined annulus to plug any channels that may have formed in the cement sheath. Squeezing is an expensive operation that requires bringing perforating and cement service companies back to the well and is therefore to be avoided, if possible.
It is critical in preparing cement compositions useful in cementing casing in the borehole of a well that they be characterized by little or no fluid loss, the presence of little or no measureable free water, a viscosity designed for optimum particle suspension, optimum pumpability, flow properties sufficient to facilitate and maintain laminar and/or plug flow, adequate gel strength to provide thixotropic properties to the slurry when pumping ceases, thickening time tailored or designed to meet field specifications, high compressive strength and substantially no shrinking on setting.
SUMMARY OF THE INVENTION
We have found a novel cement composition particularly suitable for the preparation of a novel aqueous slurry useful in cementing casing in the borehole of a well having the desirable characteristics defined above which comprises (1) cement, (2)(a) a hydroxyethylcellulose ether having a critical viscosity or (2) (b) a mixture of a hydroxyethylcellulose ether having a critical viscosity and of a hydroxypropylcellulose ether having a critical viscosity and (3) a dispersant.
The cement, or first, component of the novel cement composition suitable for preparing the novel aqueous slurry can be any of the cements defined in API, Spec. 10, First Edition, page 6, or in ASTM C150. Examples of these cements are those defined by the API Classes "A" through "J". Of these we prefer to employ those defined in API Classes "H" and "J".
In order to obtain the novel cement composition defined and claimed herein, it is critical that the second component containing the hydroxyethylcellulose ether, and the hydroxypropylcellulose ether if present, have a critical viscosity. Viscosity is empirically related to the molecular weight of the hydroxyalkylcellulose ether, and it is the molecular weight of the hydroxyalkylcellulose ether which is the critical factor. The viscosity measurement is merely a convenient way of defining the molecular weight. In addition, the hydroxyalkylcellulose ethers will desirably possess a specified degree of substitution and a specified molar substitution.
As pointed out above, the second component can contain hydroxyethylcellulose ether along or a mixture of hydroxyethylcellulose ether and of hydroxypropylcellulose ether. In our preferred embodiment, the second component will consist substantially solely of hydroxyethylcellulose ether. If hydroxypropylcellulose ether is also used in combination with hydroxyethylcellulose ether, it can be present in any amount up to about 50 weight percent, based on the total weight of said hydroxyalkylcellulose ethers, but preferably will be present in an amount ranging from about five to about 20 weight percent, based on the total weight of said hydroxyalkylcellulose ethers.
As pointed out above, the viscosity of the hydroxyalkylcellulose ethers used herein is critical in order to obtain a cement composition having the desired characteristics defined above. In obtaining the viscosity measure required, a selected amount of the hydroxyalkylcellulose ether is dissolved in water at 25° C. and the resulting aqueous solution is measured in a Brookfield viscometer. The viscosity of the hydroxyethylcellulose ether must be above about 200 centipoises when measured in a five weight percent aqueous solution but less than about 6000 centipoises when measured in a one weight percent aqueous solution. In a preferred range the viscosity will be from about 1000 to about 10,000 centipoises when measured in a two weight percent aqueous solution. The critical viscosity of the hydroxypropylcellulose ether must be above about 100 centipoises when measured in a two weight percent aqueous solution, but less than about 10,000 centipoises when measured in a one weight percent aqueous solution. In a preferred range, the viscosity will be from about 1000 to about 3000 centipoises when measured in a one weight percent aqueous solution.
The degree of substitution and the molar substitution of the hydroxyalkylcellulose ethers used herein are also important. By "degree of substitution" we mean the average number of total substituents present per glucose unit, while by "molar substitution" we mean the number of mols of ethylene oxide or propylene oxide that are attached to each glucose unit. The degree of substitution can be in the range of about 0.5 to about 3.0, preferably from about 0.9 to about 2.8. The molar substitution can be in the range of about 0.5 to about 10.0, preferably from about 1.0 to about 6.0. It is understood that the hydroxyethylcellulose ether can also carry some propylene oxide substituents and, similarly, hydroxypropylcellulose ether can also carry some ethylene oxide units.
The third component required in the novel cement composition herein is a dispersant. By "dispersant" we mean to include any anionic surfactant, that is, any compound which contains a hydrophobic (for example, any hydrocarbon substituent, such as alkyl, aryl or alkaryl group) portion and a hydrophilic (for example, any negatively-charged moiety, such as O - CO 2 - or SO 3 - ) portion. We prefer to use sulfonic acid derivatives of aromatic or aliphatic hydrocarbons, such as naphthalene sulfonic acid formaldehyde condensation product derivatives, such as their sodium or potassium salts. Examples of dispersants that can be used include polynaphthalene sulfonates available from Dow Chemical Company, such as "TIC I"; lignosulfonates; CFR-2, a sulfonate dispersant sold by the Halliburton Company; sodium naphthalene sulfonate formaldehyde condensation products, such as DAXAD 19 of W. R. Grace Company, Lomar D of Diamond Shamrock Company, D 31 of B. J. Hughes Company, and D 65 of Dowell Company; and potassium naphthalene sulfonate formaldehyde condensation products, such as DAXAD 11 KLS of W. R. Grace Company.
Other additives conventionally added to cement compositions useful in cementing casings in the borehole of a well can also be added to the novel cement compositions herein in the amounts normally used. These additives can include, for example, (1) cement accelerators, such as calcium chloride, sodium chloride, gypsum, sodium silicate and sea water; (2) light-weight additives, such as bentonite, diatomaceous earth, gilsonite, coal, perlite and pozzolan; (3) heavy-weight additives, such as hematite, ilmenite, barite, silica flour and sand; (4) cement retarders, such as lignins, calcium lignosulfonates, CMHEC (carboxymethylhydroxyethylcellulose ether) and sodium chloride; (5) additives for controlling lost circulation, such as gilsonite, walnut hulls, cellophane flakes, gypsum cement, bentonite-diesel oil and nylon fibers; and (6) filtration control additives, such as cellulose dispersants, CMHEC and latex. In addition other unconventional additives, such as Xanthan gum, as disclosed in our copending application Ser. No. 466,550, entitled "Cement Compositions and Method of Cementing Casing in a Well", filed concurrently herewith, can also be used.
Table I below defines the amounts of hydroxyalkylcellulose ethers and dispersant that can be used herein to prepare the novel cement composition based on the weight of the dry cement.
TABLE I______________________________________ Weight Percent Broad Range Preferred Range______________________________________Total Hydroxy- 0.01 to 0.6 0.1 to 0.5alkylcellulose etherDispersant 0.01 to 3.0 0.1 to 2.0______________________________________
The above novel cement composition is merely mixed with any suitable aqueous material used in preparing aqueous cement slurries, for example, water itself, to prepare the novel aqueous cement slurry possessing the desired characteristics; for example having the desired density and setting and pumping properties. Mixing of the novel cement composition with the aqueous solution can be effected in any suitable or conventional manner, for example, by mixing the dry ingredients before addition to the aqueous solution or by adding the individual components to an aqueous slurry of cement.
Table II below defines the amounts of each of the components that can be used to prepare the novel aqueous cement slurry claimed herein, based on the weight of the dry cement.
TABLE II______________________________________ Weight Percent Broad Range Preferred Range______________________________________Total Hydroxy- 0.01 to 0.6 0.1 to 0.5alkylcellulose etherDispersant 0.01 to 3.0 0.1 to 2.0Water 25 to 80 35 to 70KCl* 0 to 7 1 to 5______________________________________ *Based on the weight of the water.
The weight ratio of dispersant (D) to total hydroxyalkylcellulose ether (P) should be in the range of about 10:1 to about 1:5, preferably from about 5:1 to about 1:1.
Cement tests were carried out in the laboratory to evaluate the cement slurries prepared in accordance with out invention. The practices and procedures defined in API Spec 10, First Edition, January 1982, were followed. Appropriate bottom hole circulating temperatures (BHCT), bottom hole static temperatures (BHST) and pressures were chosen for the tests. The BHCT applies for fluid loss, free water, total thickening time, viscosity, initial gel strength and yield point tests. BHST applies for compressive strength and hesitation squeeze tests. Satisfactory results from these tests will fall within the following specifications.
The fluid loss of the above slurry, as determined in accordance with API Spec 10, First Edition, January 1982, pages 72-74, will always be below about 500 milliliters at 1000 psi (6894 kPa), generally below about 200 milliliters at 1000 psi, most generally in the range of about five to about 100 milliliters at 1000 psi.
The amount of free water in the cement slurry, as determined in accordance with the above API Spec 10, page 18, will always be below about 1.4 weight percent, generally in trace amounts (the top of the resulting cement will be moist), but most generally will be free of water (the top of the resulting cement will be dry and crusty).
The total thickening time of the slurry, as determined in accordance with the above API Spec. 10 pages 22-31, can easily be adjusted to meet field requirements. This can be, for example, within the range of about two to about eight hours, generally from about three to about eight hours, but most preferably about four to about six hours.
The viscosity of the slurry, as determined in accordance with API Bulletin RP 13B, Sixth Edition, April 1976, page 6, will be in centipoises at 300R in the range of about 30 to about 400, generally from about 50 to about 300, but most generally from about 100 to about 250.
The initial gel strength of the slurry, as determined in accordance with the above API Bulletin RP 13B, page 6, in pounds per 100 square feet at 3 RPM, will be about two to about 50 pounds/100 square feet (0.1 to 2.5 kg/m 2 ), generally about six to about 30 pounds/100 square feet (0.3 to 1.5 kg/m 2 ), but most generally from about 10 to about 20 pounds/100 square feet (0.5 to 1.0 kg/m 2 ).
The yield point of the slurry as determined in accordance with the above API Bulletin RP 13 B, page 6, in pounds/100 square feet will be in the range of about 1 to about 250 pounds/100 square feet (0.05 to 12.5 kg/m 2 ), generally from about five to about 150 pounds/100 square feet (0.25 to 7.5 kg/m 2 ), but most generally from about 8 to about 100 pounds/100 square feet (0.4 to 5.0 kg/m 2 ).
The compressive strength of the cement, upon setting, as determined in accordance with the above API Spec 10, page 49, will always be above about 1500 psig (10,342.5 kPa), generally in the range of about 2000 to about 8000 psig (13,790 to 55,160 kPa), but most generally from about 2000 to about 4000 psig (13,790 to 27,580 kPa).
We have found that, in general, the compressive strength of the cement prepared in accordance with this invention is independent of the gel strength.
The novel cement slurry herein can then be pumped downwardly into the casing that has been suspended in the borehole of a well and then circulated upwardly into the annulus surrounding the casing. Circulation can continue until the slurry fills that portion of the annular space desired to be sealed and can continue until the cement slurry returns to the surface. In one embodiment wherein the novel cement slurry herein can be utilized, the borehole can be slanted from the vertical. The cement slurry is then maintained in place until the cement sets. The cement so produced will result in a strong, continuous, unbroken bond with the outside surface of the casing and with the wall of the formation.
In a preferred method of cementing casing in a well employing the cement composition of this invention, a lead-scavenger is displaced upwardly through the annulus surrounding the casing and followed by the novel aqueous cement slurry prepared in accordance with the invention herein, for convenience in this description referred to as "pay slurry". An example of a lead-scavenger cement slurry that can be used herein is a gel cement slurry cntaining, for example, from about 10 to about 20 weight percent bentonite, based on the weight of the cement, and about 0 to about 1.0 weight percent of a lignosulfonate retarder. The cement and bentonite are then mixed with sea water, or an aqueous solution containing about three weight percent sodium chloride, to form a slurry having a density of about 11.0 to about 14.0 pounds per gallon (1320 to 1680 grams per liter). The lead-scavenger cement slurry has a low viscosity which results in turbulent flow of the slurry through the annulus at substantially lower velocities than are necessary for turbulent flow of the pay slurry. The lead-scavenger slurry removes drilling mud and the drill cuttings which are present between the wall of the borehole and the outer surface of the casing. The pay slurry of the cement follows the lead-scavenger slurry into the annulus and is held in place until the cement sets. The annular flow patterns, reported in Reynolds No. values, for the scavenger slurry are generally maintained within the range of about 2000 to about 4000, preferably about 2500 to about 3500, while those for the pay slurry are maintained within the range of about 400 to about 1900, preferably about 500 to about 1800.
DESCRIPTION OF PREFERRED EMBODIMENTS
A number of cement slurries were prepared from a number of cement compositions and tested. Each cement slurry was prepared using 800 grams of Class H cement. In each of Runs Nos. 1 to 40, 46 weight percent of water, based on the dry cement, was used. In Run No. 41, 40 weight percent of water, based on the weight of the dry cement, was used. The cement slurries so prepared and the test results based thereon are further defined below the Table III. The viscosities of the hydroxyalkylcellulose ethers used in the preparation of the cement slurries are set forth below in Table IV.
TABLE III Yield Gel Point Compressive Strength #/100 ft.sup.2 Strength API #/100 ft.sup.2 (0.05 Total #/in.sup.2 Viscosity.sup.2 % of Fluid Viscosity (0.05 kg/m.sup.2) Thickening (6.895 Run % Viscosity.sup.2 % of % % Other BHCT Loss % Free cp kg/m.sup.2) 300R- Time, kPa) No. HEC.sup.1 of HEC.sup.1 HPC.sup.3 HPC.sup.3 Dispersant.sup.4 KCl Additives D/P.sup.5 °F.(. degree.C.)(ml) Water 300R 3R (600R-300R) Hrs. 48 Hrs. Remarks 1 0 -- 0 -- 1.0 5 -- -- 152 (67) 928 11 20 3 -4 .sup. NT.sup.7 .sup. NT.sup.7 Too thin 2 0.2 N250MBR 0 -- 1.0 5 -- 5.0 152 (67) 132 0 NT.sup.7 .sup. NT.sup.7 .sup. NT.sup.7 NT NT -- 3 0.17 N250MBR 0.03 KH 1.0 5 -- 5.0 152 (67) 136 0 77 4 13 NT NT -- 4 0.17 N250MBR 0.03 KG 1.0 5 -- 5.0 152 (67) 173 0 75 3 19 NT NT -- 5 0.17 N250MR 0.03 KH 1.0 5 -- 5.0 152 (67) 212 0 110 2 2 NT NT -- 6 0.17 N250MR 0.03 KG 1.0 5 -- 5.0 152 (67) 174 0 52 5 11 NT NT -- 7 0.17 N250LR 0.03 KH 1.0 5 -- 5.0 152 (67) 574 3 24 3 -1 NT NT Too thin 8 0.17 N250LR 0.03 KG 1.0 5 -- 5.0 152 (67) 602 3 22 3 - 1 NT NT Too thin 9 0.17 N210LR 0.03 KH 1.0 5 -- 5.0 152 (67) 536 3 20 2 -3 NT NT Too thin 10 0.17 N210LR 0.03 KG 1.0 5 -- 5.0 152 (67) 610 Trace 21 2 -3 NT NT Too thin 11 0.17 N250HHR 0.03 KH 1.0 5 -- 5.0 152 (67) 148 0 82 3 12 NT NT -- 12 0.17 N250HHR 0.03 KG 1.0 5 -- 5.0 152 (67) 140 0 74 4 5 NT NT -- 13 0.17 N250HHW 0.03 KH 1.0 5 -- 5.0 152 (67) 148 0 75 2 16 NT NT -- 14 0.17 N250HHW 0.03 KG 1.0 5 -- 5.0 152 (67) 158 0 77 3 20 NT NT -- 15 0.17 N250H4R 0.03 KH 1.0 5 -- 5.0 152 (67) 136 Trace 74 3 17 NT NT -- 16 0.17 N250H4R 0.03 KG 1.0 5 -- 5.0 152 (67) 139 0 75 4 10 NT NT -- 17 0.25 N250MBR 0 -- 1.0 5 -- 4.0 152 (67) 86 0 NT NT NT NT NT -- 18 0.30 N250MBR 0 -- 1.0 5 -- 3.33 152 (67) 60 0 NT NT NT NT NT -- 19 0.35 N250MBR 0 -- 1.0 5 -- 2.86 152 (67) 52 0 NT NT NT NT NT -- 20 0.40 N250MBR 0 -- 1.0 5 -- 2.50 152 (67) 46 0 NT NT NT NT NT -- 21 0.213 N250MBR 0.037 KH 1.0 5 -- 4.0 152 (67) 106 0 113 3 32 NT NT -- 22 0.255 N250MBR 0.045 KH 1.0 5 -- 3.33 152 (67) 86 0 146 5 44 NT NT -- 23 0.298 N250MBR 0.052 KH 1.0 5 -- 2.86 152 (67) 56 0 120 5 48 NT NT -- 24 0.34 N250MBR 0.06 KH 1.0 5 -- 2.5 152 (67) 55 Trace 180 10 80 NT NT -- 25 0.34 N250HHR 0.06 KH 1.0 5 -- 2.5 152 (67) 44 0 271 17 242 NT NT -- 26 0.34 N150HHW 0.06 KH 1.0 5 -- 2.5 152 (67) 33 0 227 11 154 NT NT -- 27 0.34 N250H4R 0.06 KH 1.0 5 -- 2.5 152 (67) 42 0 229 13 182 NT NT -- 28 0.14 N250MBR 0.06 KH 1.0 5 -- 5.0 152 (67) 214 Trace 63 5 11 NT NT -- 29 0.175 N250MBR 0.075 KH 1.0 5 --4.0 152 (67) 137 Trace 74 3 13 NT NT -- 30 0.21 N250MBR 0.09 KH 1.0 5 -- 3.33 152 (67) 106 Trace 110 5 35 NT NT -- 31 0.245 N250MBR 0.105 KH 1.0 5 -- 2.86 152 (67) 94 Trace 110 7 36 NT NT -- 32 0.28 N250MBR 0.120 KH 1.0 5 -- 2.5 152 (67) 70 Trace 158 7 68 NT NT -- 33 0.10 N250MBR 0.10 KH 1.0 5 -- 5.0 152 (67) 400 3 37 7 -3 NT NT Too thin* 34 0.125 N250MBR 0.125 KH 1.0 5 -- 4.0 152 (67) 306 2 51 12 7 NT NT * 35 0.15 N250MBR 0.15 KH 1.0 5 -- 3.33 152 (67) 175 2 64 3 8 NT NT * 36 0.175 N250MBR 0.175 KH 1.0 5 -- 2.86 152 (67) 189 1 68 6 10 NT NT -- 37 0.20 N250MBR 0.20 KH 1.0 5 -- 2.5 152 (67) 149 1 83 5 20 NT NT -- 38 0.255 N250MBR 0.045 KH 1.0 3 0.10 2.5 152 (67) 86 0 NT NT NT NT 1550 -- Xanthan Gum 39 0.34 N250MBR 0.06 KH 1.089 3 0.08 2.27 201 (94) 54 0 NT NT NT 4.40 NT -- CMHEC.sup.6 40 0.34 N250MBR 0.06 KH 0.908 3 -- 2.27 201 (94) 90 0 NT NT NT 3.13 3319 -- 41 0.374 N250MBR 0.066 KH 1.195 0 0.1 2.21 256 (125) 44 0 NT NT NT NT 2990 -- CMHEC.sup.6 .sup.1 hydroxyethylcellulose ether .sup.2 defined in Table IV below .sup.3 hydroxypropylcellulose ether .sup.4 CFR2, a sulfonate dispersant of Haliburton Company .sup.5 Weight ratio of dispersant to total celluloses in system .sup.6 carboxymethylhydroxyethylcellulose ether .sup.7 "NT" throughout the table means Not Taken *Free water too high
TABLE IV______________________________________Hydroxy-alkyl- Molarcellulose Substi- Viscosity, CentipoisesEther tution 1 Wt % 2 Wt % 5 Wt %______________________________________N250MBR 2.5 -- 4500-6500 --N250MR 2.5 -- 4500-6500 --N250HHR 2.5 3400-5000 -- --N150HHW 1.5 3400-5000 -- --N250H4R 2.5 2600-3300 -- --N210LR 2.1 -- -- 75-150N250LR 2.5 -- -- 75-150KH ˜4 1500-2500 -- --KG ˜4 -- 150-400 --______________________________________
A study of the data in Table III above clearly illustrates the superior and beneficial results arising from the novel cement slurries prepared using our novel cement compositions. The absence of the specific hydroxyalkylcellulose ethers in Run No. 1 results in a cement slurry having a fluid loss of 928 milliliters, the presence of 11 weight percent free water and a yield point of -4, showing solids separation and a slurry that was too thin to be useful or satisfactory in well cementing operations. Runs Nos. 3-16 and 25-27 show the effect of using hydroxyalkylcellulose ethers of varying viscosities. Thus, when the viscosities of the hydroxyalkylcellulose ethers were outside the critical ranges defined herein in each of Runs Nos. 7-10, the cement slurry was too thin to be useful in well cementing operations. Runs Nos. 2 and 17-24 and 28-37 show the effect of varying the ratio of hydroxyethylcellulose ether to hydroxypropylcellulose, ether from 100:0 to 50:50. Examination of Runs 33-35 wherein the hydroxyethylcellulose ether to hydroxypropylcellulose ether ratio is 50:50, shows unsatisfactory performance. For this reason we prefer to use a hydroxyethylcellulose ether to hydroxypropylcellulose ether ratio of less than 50:50. Runs Nos. 38 and 39 show the advantageous results obtained by the additional presence of xanthan gum and of carboxymethylhydroxyethylcellulose ether, respectively, in the novel cement composition herein. A comparison of Run No. 40 with Run No. 39 shows that the presence of carboxymethyhydroxyethylcellulose ether in Run No. 39 further reduces fluid loss in the cement. Run No. 41 additionally shows that the presence of KCl in the cement slurry is not critical.
Obviously, many modifications and variations of the invention, as hereinabove set forth, can be made without departing from the spirit and scope thereof, and therefore only such limitations should be imposed as are indicated in the appended claims.
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A novel cement composition for the preparation of a novel aqueous slurry useful in cementing casing in the borehole of a well comprising (1) cement, (2) (a) a hydroxyethylcellulose ether having a critical viscosity or (2) (b) a mixture of a hydroxyethylcellulose ether having a critical viscosity and of a hydroxypropylcellulose ether having a critical viscosity and (3) a dispersant.
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This application is a National Stage Application of PCT/1N20078/004245, filed Oct. 5, 2006, which claims benefit of Serial No. 676/KOL/2006, filed Jul. 5, 2006 in India and which application(s) are incorporated herein by reference. To the extent appropriate, a claim of priority is made to each of the above disclosed applications.
FIELD OF THE INVENTION
The present invention relates to a process for preparation of optically pure or optically enriched enantiomers of sulphoxide compounds, such as omeprazole and structurally related compounds, as well as their salts and hydrates.
BACKGROUND OF THE INVENTION
Substituted 2-(2-pyridinylmethylsulphinyl)-1H-benzimidazoles of formula (I) are useful
as inhibitors of gastric acid secretion.
wherein R 1 , R 2 and R 3 are the same or different and selected from hydrogen, alkyl, alkylthio, alkoxy optionally substituted by fluorine, alkoxyalkoxy, dialkylamino, and halogen; R 4 -R 7 are the same or different and selected from hydrogen, alkyl, alkoxy, halogen, halo-alkoxy, alkylcarbonyl, alkoxycarbonyl, and trifluoroalkyl.
For example, the compounds with generic names omeprazole, lansoprazole, rabeprazole, pantoprazole are used in the treatment of peptic ulcer. These compounds have a chiral center at the sulphur atom and thus exist as two optical isomers, i.e. enantiomers.
It has been well recognized in several pharmacologically active compounds that one of the enantiomer has superior biological property compared to the racemate and the other isomer.
For example, omeprazole (CAS Registry No. 73590-58-6), chemically known as 5-methoxy-2-{[(4-methoxy-3,5-dimethyl-2-pyridinyl)methyl]sulphinyl}-1H-benzimidazole, is a highly potent inhibitor of gastric acid secretion. It has a chiral center at the sulphur atom and exists as two enantiomers (S)-(−)-omeprazole and (R)-(+)-omeprazole. It has been shown that the (S)-enantiomer of omeprazole has better pharmacokinetic and metabolic properties compared to omeprazole. The (S)-enantiomer of omeprazole having generic name esomeprazole is marketed by Astra Zeneca in the form of magnesium salt under the brand name NEXIUM®. Therefore, there is a demand and need for an industrial scale process for manufacturing esomeprazole.
The methods of synthesis of racemic sulphoxide compounds of formula (I) are very successful for a large-scale industrial manufacture. However, the production of optically pure sulphoxide compounds of formula (I) is not easy.
The prior art methodologies for the preparation of single enantiomers of sulphoxides of formula (I) are based on enantioselective or chiral synthesis, optical resolution of the racemate, separation by converting the racemate to diastereomers, or by chromatography.
For example, some of the earliest prior art on enantioselective synthesis of the single enantiomers of sulphoxides of formula (I) described in Euro. J. Biochem. 166, (1987), 453, employed asymmetric sulphide oxidation process developed and reported by Kagan and co-workers in J. Am. Chem. Soc. 106 (1984), 8188. The process disclosed therein provides sulphoxide products in an enantiomeric excess of only about 30%, which upon several recrystallization steps yielded optically pure sulphoxide up to an e.e. of 95%. The oxidation was performed by using tert-butyl hydroperoxide as oxidizing agent in the presence of one equivalent of a chiral complex obtained from Ti(OiPr) 4 /(+) or (−)-diethyl tartrate/water in the molar ratio of 1:2:1. A minimum of 0.5 equivalent of titanium reagent was found to be a must for obtaining very high enantioselectivity.
An improvement in the above oxidation process to obtain higher enantioselectivity was reported by Kagan and co-workers in Tetrahedron (1987), 43, 5135; wherein tert-butyl hydroperoxide was replaced by cumene hydroperoxide. In their further study reported in Synlett (1990), 643; Kagan and co-workers found that high enantioselectivity can be obtained if the temperature is maintained between −20° C. to −40° C., and methylene chloride is used as a solvent.
In contrary to Kagan's observation of requirement of low temperature and chlorinated solvent like methylene chloride for high enantioselectivity of the chiral oxidation, Larsson et al in U.S. Pat. No. 5,948,789 (equivalent to PCT publication WO 96/02535) have described an enantioselective process for the synthesis of the single enantiomers of compound of formula (I) by the chiral oxidation of the pro-chiral sulphide of formula (Ia) utilizing a chiral titanium (IV) isopropoxide complex in solvent systems such as toluene, ethyl acetate at 20-40° C., and most importantly a base like amine such as triethyl amine or diisopropyl amine.
Although the formation of % e.e. of the desired isomer is satisfactory, the method suffers from the disadvantage (a) of low chemical conversion; (b) formation of undesired sulphide and sulfone impurities in substantial amounts, necessitating further purification by one or more tedious crystallization.
It is obvious from the above that such conversions which result in low chemical conversion and require costly metal complex and protracted purification, surely, is not desirable process for making a product such as optically active prazole in an industrial scale.
WO 96/17076 teaches a method of enantioselective biooxidation of the sulphide compound (Ia), which is effected by the action of Penicillium frequentans, Brevibacterium paraffinolyticum or Mycobacterium sp.
WO 96/1707 teaches the bioreduction of the racemic omeprazole to an enantiomer or enantiomerically enriched sulphide of formula (Ia), which is effected by the action of Proteus vulgaris, Proteus mirabilis, Escherichia coli, Rhodobacter capsulatus or a DMSO reductase isolated from R. capsulatus.
The separation of enantiomers of omeprazole in analytical scale is described in Marie et al.; J. Chromatography, 532, (1990), 305-19. WO 03/051867 describes a method for preparation of an enantiomerically pure or optically enriched enantiomer of either omeprazole, pantoprazole, lansoprazole, or raberpazole from a mixture containing the same using means for simulated moving bed chromatography with a chiral stationary phase such as amylose tris(S)-methylbenzycarbanmate. However, chromatographic methods are not suitable for large-scale manufacture of these prazoles.
The optical resolution methods taught in the art for separating the enantiomers of certain 2-(2-pyridinylmethylsulphinyl)-1H-benzimidazoles of formula (I) utilizes the diastereomer method, the crystallization method or the enzyme method.
The resolution process disclosed in DE 4035455 and WO 94/27988 involve converting the racemate 2-(2-pyridinylmethylsulphinyl)-1H-benzimidazoles to a diastereomeric mixture using a chiral acyl group, such as mandeloyl, and the diastereomers are separated and the separated diastereomer is converted to the optically pure sulphoxide by hydrolysis.
The method suffers from the following disadvantages,
(i) the resolution process involves additional steps of separation of diastereomeric mixture, and hydrolysis of the N-substituent in separated diastereomer, (ii) the conversion of the racemate to diastereomeric acyl derivative is low yielding (˜40%), (iii) the diastereomer from the unwanted (R)-enantiomer is separated and discarded,
WO 2004/002982 teaches a method for preparation of optically pure or optically enriched isomers of omeprazole by reacting the mixture of optical isomers with a chelating agent (D)-diethyl tartrate and transition metal complex titanium (IV) isopropoxide to form a titanium metal complex in an organic solvent such as acetone in presence of a base such as triethyl amine, which is then converted to salt of L-mandelic acid. The mandelic acid salt of the titanium complex of optical isomer derived from (S)-enantiomer of omeprazole gets precipitated, which is separated and purified to obtain chiral purity of about 99.8%.
Optically active 1,1′-bi-2-naphthol (BINOL) and its derivatives are useful as chiral ligands in catalysts for asymmetric reactions to hosts for molecular recognition and enantiomer separation, and often intermediates for the synthesis of chiral molecules.
BINOL is known to form crystalline complexes with a variety of organic molecules through hydrogen bonding. The (S) and/or (R) BINOL was found to be useful as a chiral host for enantioselective complexation. The application of BINOL in resolution of omeprazole is disclosed Deng et al in CN 1223262.
The Chinese patent application CN 1223262 (Deng et al) teaches the utility of chiral host compounds such as dinaphthalenephenols (BINOL), diphenanthrenols or tartaric acid derivatives in the resolution of prazoles. The method consists of formation of 1:1 solid complex between the chiral host and one of the enantiomer of the prazole, the guest molecule. The other enantiomer remains in the solution. The racemic prazole is treated with the chiral host in a mixture of solvent comprising of aromatic hydrocarbon solvents such as benzene, alkyl substituted benzene or acetonitrile and, hexane. The solid complex is separated from the solution, and dissolved again in afresh solvent system by heating to 60-130° C. and then keeping at −20-10° C. for 6-36 hrs to obtain higher e.e. value for the solid complex. The process is repeated many times to obtain high e.e. values for the solid complex. The host and the guest in the solid complex are separated by column chromatography. The final separated single enantiomer of the prazole is then recrystallized from a mixture of methylene chloride or chloroform and, ether.
In a later publication in Tetrahedron Asymmetry 11 (2000), 1729-1732 the inventors of the above mentioned Chinese patent application reported the resolution of omeprazole using (S)-BINOL. An inclusion complex of (S)-BINOL and (S)-omeprazole was obtained as a grey-blue complex with 90.3% e.e. by mixing racemate omeprazole and (S)-(−)-BINOL in the mole ratio 1:1.5, in a solvent mixture of benzene:hexane (v/v=4:1) at 110° C. The inclusion complex obtained was further purified by recrystallization in benzene:hexane (v/v, 1:1) and separated on a silica gel column to yield (S)-(−)-omeprazole with 98.9% e.e. and 84.1% overall yield. The (S)-(−)-omeprazole so obtained was recrystallized in water to obtain as a white powder with 99.2% e.e.
In this publication, the authors have reported their observation of criticality of the benzene:hexane solvent ratio in obtaining the inclusion complex and the enantioselectivity. The authors reportedly have obtained the best enantioselectivity of 90.3% e.e. when the solvent ratio of benzene:hexane is 4:1 and the mole ratio of racemate omeprazole and (S)-(−)-BINOL is 1:1.5.
Further, by comparing the IR stretching frequencies observed for S═O bond in racemate omeprazole (1018 cm −1 ) and its inclusion complex with (S)-(−)-BINOL (1028 cm −1 ), the authors have concluded that the S═O bond which involved in a N—H . . . O═S hydrogen bond does not attribute the formation of hydrogen bonding in the inclusion complex, and the chiral recognition in the inclusion complex may occur via formation of hydrogen-bonded supramolecular chiron.
The method described in the above-mentioned Chinese patent application suffers in that,
(i) due to very low e.e. value for the solid complex obtained for the first time, the complexation process has to be repeated till the desired e.e. value is obtained, (ii) to separate the host and the guest, one has to take recourse to tedious chromatographic methods, (iii) overall the resolution involves several operations of complex formation, separation, purification by chromatography and recrystallization, (iv) For the purpose of chromatography the amount silica and the solvent required is exorbitant (v) with more operation steps, there is considerable material loss leading to lowering of the overall yield, which is not satisfactory for a commercial scale production, (vi) the use of hexane with low flash point is not recommended for industrial processes, (vii) volumes of the solvents to be handled having low flash point are quite large, necessitating special design of plant and machinery for safety, (viii) benzene is carcinogenic and is listed as a class 1 solvent in ICH guideline.
Taking these considerations, the process disclosed in the CN 1223262 (Deng et al) does not give cost effective and eco-friendly method of manufacture.
It is evident from the above that there is a need for synthesizing optically pure sulphoxide compounds of formula (I), their salts, and their hydrates by a process that is (a) cost effective (b) simple (c) easy to operate (d) eco-friendly, (e) consistently give good yields and purity with minimum variables (e) highly reproducible.
The present invention provides such a solution.
OBJECT OF THE INVENTION
The object of the invention is to provide an improved method for the manufacture of single enantiomers of the sulphoxide compounds of the formula (I) and their pharmaceutically acceptable salts and hydrates, thereby resulting in significant economic and technological improvement over the prior art methods.
More specifically, the object of the invention is to manufacture single enantiomers of Omeprazole, Rabeprazole, Lansoprazole or Pantoprazole covered by the formula (I), and pharmaceutically acceptable salts and hydrates.
SUMMARY OF THE INVENTION
Thus, according to one aspect of present invention there is provided a process for preparation of an optically pure or optically enriched enantiomer of a sulphoxide compound of formula (I), said process comprises:
a) providing, a mixture of optical isomers of the sulphoxide compound of formula (I) as starting material, in an organic solvent; the different optical isomers having R and S configurations at the sulfur atom of the sulphoxide group; b) reacting the mixture of optical isomers, in the organic solvent, with a chiral host; c) separating the adduct formed by the enantiomer and the chiral host; d) if desired, repeating the operation of step (b); e) treating the adduct obtained in step (c) or (d) with a metal base selected from Group I or Group II metal, thereby obtaining the metal salt of the enantiomer of the sulphoxide compound in a substantially optically pure or optically enriched form; f) optionally, converting the Group I metal salt of substantially optically pure or optically enriched enantiomer of the sulphoxide compound obtained in step (e) to magnesium salt.
BRIEF DESCRIPTION OF FIGURES
FIG. 1 illustrates an infrared (IR) spectrum of racemic omeprazole.
FIG. 2 illustrates an IR spectrum of S-BINOL.
FIG. 3 illustrates an IR spectrum of the host-guest inclusion complex including S-BINOL and esomeprazole.
FIG. 4 illustrates an X-ray powder diffraction pattern of the host-guest inclusion complex including S-BINOL and esomeprazole.
FIG. 5 illustrates an X-ray powder diffraction pattern of an amorphous form of esomeprazole magnesium salt.
DETAILED DESCRIPTION OF THE INVENTION
The invention is directed to a process for preparation of an optically pure or optically enriched enantiomer of a sulphoxide compound of formula (I). Intermediates in the processes of this invention are also part of this invention, as are their salts and hydrates. The sulphoxide compounds suitable as substrates for the process of this aspect of the invention include, for example, omeprazole, lansoprazole, pantoprazole, rabeprazole In a preferred embodiment in step (b), the chiral host is optically pure or optically enriched (S)-(−)-BINOL or (R)-(+)-BINOL.
In a more preferred embodiment, the invention provides a specific process for preparing a substantially optically pure or optically enriched form of omeprazole and its pharmaceutically acceptable salts. In other preferred aspect, the invention also provides an amorphous form of magnesium salt of esomeprazole trihydrate.
The process is depicted in the following Scheme 1
In their endeavor to obtain optically pure enantiomer of the sulphoxide compounds of the formula (I), for example the (S)-omeprazole from racemate omeprazole or optically enriched omeprazole by resolution method using BINOL, the present inventors surprisingly found that,
(i) use of mixture of toluene and cyclohexane significantly improved the e.e. value of the inclusion complex of (S)-BINOL and (S)-omeprazole, (ii) the inclusion complex of (S)-BINOL and (S)-omeprazole can be directly converted to Group I or Group II metal salt of (S)-omeprazole without any further purification of the complex by recrystallization and separation of the host and the guest by chromatography, (iii) the (S)-BINOL and the other isomer (R)-omeprazole could be recovered and recycled, (iv) the methodology could be conveniently adopted for other sulphoxide compounds such as Rabeprazole, Lansoprazole, or Pantoprazole,
The present method addresses the drawbacks of the resolution using chiral host disclosed in the CN 1223262 by,
(i) providing the chiral complex in very high e.e. in minimum number of operational steps, (ii) obviates the usage of hexane which is having low flash point, (iii) utilizes cyclohexane which is a preferred solvent over hexane as the allowed limit of residual solvent for cyclohexane is 3880 ppm, while it is 290 ppm for hexane, in the ICH guideline, (iv) significantly increases the overall yield through recovering of the chiral material and racemization of the undesired isomer,
In one embodiment of the process aspect of the invention, the starting material is a compound of the formula (I). In one variant, R 1 , R 2 are methyl; R 2 and R 5 are methoxy; and R 4 , R 6 , and R 7 are hydrogen. In another variant R 4 , R 5 , R 6 , and R 7 are hydrogen; R 1 is hydrogen; R 3 is methyl, and R 2 may be —O(CH 2 ) 3 OCH 3 or —OCH 2 CF 3 . In a further variant, R 1 , R 4 , R 6 and R 7 are hydrogen; R 5 is difluoromethoxy; and R 2 and R 3 are methoxy. Specific starting materials that are suitable include omeprazole, lansoprazole, rabeprazole, and pantoprazole.
Initially, a solution of the racemic mixture of the sulphoxide compound of formula (I) is provided in an organic solvent, by suspending or dissolving the compound of formula (I). As used herein, the term “solvent” may be used to refer to a single compound or a mixture of compounds. Suitable organic solvents are preferably alkyl benzenes and cyclohexane. Among the alkyl benzenes, toluene and xylene are preferred. Preferably, the organic solvent is at least a mixture of alkyl benzene such as toluene or xylene and cyclohexane. More preferably, the organic solvent is a mixture of toluene and
cyclohexane.
Suitable chiral host include 1,1′-bi-2-naphthol (BINOL), diphenanthrenols or tartaric acid derivatives. Preferably, the (S)-(−)-BINOL or (R)-(+)-BINOL are used. The (S)-(−)-BINOL or (R)-(+)-BINOL may be used in optically pure or optically enriched form.
By mixing the chiral host with the racemate sulphoxide of formula (I) (guest molecules) in the solvent and gently warming to about 50-55° C., the chiral host forms an adduct with one of the enantiomer by a chiral recognition or molecular recognition process. The adduct known as a host-guest inclusion complex is formed via selectively and reversibly including the chiral guest molecules in host lattice through non-covalent interactions such as hydrogen bonding.
The host-guest inclusion complex crystallizes out as solid compound upon lowering the temperature, from ambient to about 0-10° C. The complex was separated out, washed with the solvent. If desired, the separated host-guest inclusion complex may be re-dissolved in the solvent and crystallized out.
By these operations, the process achieves the physical separation of the two enantiomers of the sulphoxide compound of formula (I), one enantiomer in the form of a host-guest inclusion complex and the other enantiomer remains in the solution.
If only one enantiomer is desired, the other may be racemized, in any way known to those skilled in the art, to obtain the starting material sulphoxide of formula (I). The racemization permits increased utilization of the material since the racemized product may be re-used in the process as described.
The adduct is treated with a metal base (MB) where M is the metal of Group I or Group II in an alcoholic solvent selected from methanol, ethanol, isopropanol, and tent-butyl alcohol or mixtures thereof to obtain the corresponding metal salt of optically pure optically enriched enantiomer of the sulphoxide compound of formula (I).
In one embodiment, the adduct is treated with a metal base of Group I metal to obtain an alkali metal salt of optically pure optically enriched enantiomer of the sulphoxide compound of formula (I). The alkali metal salt is then converted to the magnesium salt.
The preferred metal base of Group I metal are potassium hydroxide or sodium hydroxide.
In another embodiment, the adduct is directly converted to the magnesium salt of optically pure optically enriched enantiomer of the sulphoxide compound of formula (I), for instance, by treating with magnesium in methanol.
In a further embodiment, the adduct is first converted to an alkaline earth metal salt such as barium or calcium by treating with their oxide or hydroxide in an alcoholic solvent, and subsequently converted to the magnesium salt.
The preferred embodiment of the process aspect of the invention involves preparation of the (S) enantiomer of omeprazole, known as esomeprazole, and its salts. The scheme 2 illustrates the preferred process contemplated by the inventors.
Racemic omeprazole, was treated with the chiral host (S)-(−)-BINOL, in toluene-cyclohexane (4:1 v/v). A bluish gray adduct, the inclusion complex was formed between the (S)-BINOL and (S)-isomer of omeprazole, which was separated by filtration and washed with a mixture of cyclohexane and toluene. The optical purity of esomeprazole in the complex as measured by HPLC was not less than 99.5% e.e.
The IR-spectra of racemic omeprazole, (S)-BINOL and the host-guest inclusion complex is provided in FIGS. 1 , 2 , and 3 respectively. There is no significant difference in the stretching frequency of S═O bond in racemate omeprazole (1017 cm −1 ) as compared to the stretching frequency of 1028 cm −1 in the inclusion complex.
The adduct isolated is treated with potassium hydroxide or sodium hydroxide in an alcoholic solvent selected from methanol, ethanol, isopropanol, and tent-butyl alcohol or mixtures thereof to obtain the potassium or sodium metal salt of optically pure optically enriched enantiomer of the sulphoxide compound of formula (I).
The sodium or potassium salt of optically pure optically enriched enantiomer of the sulphoxide compound of formula (I) is converted to magnesium salt by treating with MgSO 4 .
In another embodiment the (S)-omeprazole-(S)-(−)-BINOL adduct is converted directly to its magnesium salt by treating with magnesium in methanol as depicted in Scheme 2.
The esomeprazole magnesium obtained by the process is in an amorphous form characterized by powder X-ray diffraction pattern given in FIG. 5 .
Alternatively, if (R)-enantiomer of omeprazoele is desired, (R)-(+)-BINOL may be used in the process described above.
The following examples illustrate the practice of the invention without being limiting any way.
EXAMPLE 1
Preparation of (S)-omeprazole-(S)-(−)-BINOL complex
Omeprazole (100 g, 0.2898 mole) was added to a mixture of toluene (1600 ml) and cyclohexane (400 ml) in a round bottom flask kept at 25-30° C. (S)-(−)-BINOL (124.3 g, 0.4346 mole) was added and the content warmed to about 50-55° C. with stirring for 30-45 minutes. The content of the flask was allowed to attain the ambient temperature and then cooled to 0-5° C. with stirring for about an hour. The (S)-omeprazole-(S)-(−)-BINOL complex crystallizes out, filtered and washed with a mixture of cyclohexane/toluene (1:4, v/v) pre-cooled to 0-5° C. The (S)-omeprazole-(S)-(−)-BINOL complex was dried at 35-40° C. under reduced pressure. The e.e. of (S)-omeprazole in the complex was found to be 99.5%. Yield: 85%.
The IR spectrum of the complex is given in FIG. 3 . The powder X-ray diffraction pattern is given in FIG. 4
EXAMPLE 2
Preparation of Esompeprazole Potassium Salt
To a solution of potassium hydroxide (31 g, 0.5535 mole) in methanol (500 ml) kept in a round bottom flask was added (S)-omeprazole-(S)-(−)-BINOL complex (100 g, 0.1584 mole) with stirring at 25-30° C. The content of the flask were stirred for about 2-2.5 hrs at 25-30° C. and then cooled to 0-5° C. and stirred for a further period of about 1-1.5 hrs. The potassium salt of esomeprazole was filtered, washed with cold methanol (50 ml), followed by washing with cold acetone (100 ml) and dried under suction. The optical purity of esompeprazole potassium as tested by HPLC was not less than 99.5%. Yield: 80%.
EXAMPLE 3
Preparation of Esomeprazole Magnesium Salt
To a solution of esomeprazole potassium salt (100 g, 0.261 mole) in methanol (500 ml) kept in a round bottom flask, was added magnesium sulphate heptahydrate (64.1 g, 0.26 mole) at 25-30° C. and stirred for 1.5-2 hrs. The insoluble material formed was filtered off and the filtrate was passed through a 0.45 micron membrane filter. To the filtrate, water (1300 ml) was added and stirred at 25-30° C. for 1-1.5 hrs, cooled to 0-5° C., and stirred for a further period of 1-1.5 hrs. The solid formed was collected by filtration and washed with water and dried under reduced pressure at 40-45° C. to obtain the esomeprazole magnesium salt.
Yield: 45%.
Optical purity: 100%
Optical rotation: [α] D =−142.04° at 25° C. and c=0.5% in methanol
e.e.: 100%
The esomeprazole magnesium salt obtained is in an amorphous form as characterized by its powder X-ray diffraction pattern given in FIG. 5 .
The moisture content of the product is 7.5% by TGA, indicating that the product is a trihydrate.
EXAMPLE 4
Preparation of Esomeprazole Magnesium Salt
To a suspension of Magnesium turnings (0.5 g, 0.0208 mole) in methanol (15 ml) was added methylene chloride (0.5 ml), stirred for about 1.5-2 hrs at 55-60° C. (S)-omeprazole-(S)-(−)-BINOL complex (2 g, 0.0030 moles) was added and stirred for 45-60 minutes. The insoluble salts were filtered off. To the combined filtrate was added water (30 ml), stirred for about 45-60 minutes and cooled to 0-5° C. to obtain a solid, which was collected by filtration and dried.
Yield: 35.4%
e.e.: 99.6%
optical purity: 99.8%
EXAMPLE 5
Preparation of (S)-rabeprazole-(S)-(−)-BINOL complex
To a mixture of toluene (100 ml) and cyclohexane (150 ml) in a round bottom flask was added rabeprazole (10 g, 0.0278 mole), and gently warmed to 48-52° C. for 30-45 minutes. The reaction mass was cooled to 25-30° C. and further cooled to 3-8° C., stirred for 45-60 minutes to isolate a solid product, which was washed with cold cyclohexane-toluene (1:1 v/v). The product was dried at 35-40° C. under reduced pressure.
Yield: 55.6%
e.e.: 99.8%
optical purity: 99.9%
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A process for preparation of optically pure or optically enriched enantiomers of sulphoxide compounds of formula (I), such as omeprazole and structurally related compounds, as well as their salts and hydrates. The said process comprises
a) providing, a mixture of enantiomers of the sulphoxide compound of formula (I) as starting material, in an organic solvent; said enantiomers having R and S configurations at the sulfur atom of the sulphoxide group; b) treating the mixture of enantiomers, in the organic solvent, with a chiral host; c) separating the adduct formed by the enantiomer and the chiral host; d) if desired, repeating the operation of step (b); e) treating the adduct obtained in step (c) or (d) with metal base selected from Group I and Group II metal, thereby obtaining metal salt of one of the optical isomers of the sulphoxide compound in optically pure or optically enriched form; f) optionally, converting the Group I metal salt of optically pure or optically enriched form the optical isomers of the sulphoxide compound obtained in step (e) to magnesium salt.
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REFERENCE TO COPENDING APPLICATIONS
This application is a continuation-in-part of U.S. patent applications Ser. No. 508,959 and Ser. No. 508,907, filed June 29, 1983, now U.S. Pat. Nos. 4,471,147 and 4,450,311, respectively, incorporated herein by reference.
FIELD OF THE INVENTION
This invention relates to processes and apparatus for converting olefins to higher hydrocarbons, such as gasoline-range and/or distillate-range fuels. In particular it relates to techniques for operating a catalytic reactor system and feedstock fractionation system.
BACKGROUND OF THE INVENTION
Improved catalytic hydrocarbon conversion processes have created interest in utilizing olefinic feedstocks, such as petroleum refinery streams rich in lower olefins, for producing C 5 + gasoline, diesel fuel, etc. In addition to the basic work derived from ZSM-5 type zeolite catalyst research, a number of discoveries have contributed to the development of a new industrial process, known as Mobil Olefins to Gasoline/Distillate ("MOGD"). This process has significance as a safe, environmentally acceptable technique for utilizing refinery streams that contain lower olefins, especially C 2 -C 5 alkenes. This process may supplant conventional alkylation units. In U.S. Pat. Nos. 3,960,978 and 4,021,502, Plank, Rosinski and Givens disclose conversion of C 2 -C 5 olefins, alone or in admixture with paraffinic components, into higher hydrocarbons over crystalline zeolites having controlled acidity. Garwood et al have also contributed improved processing techniques to the MOGD system, as in U.S. Pat. Nos. 4,150,062, 4,211,640 and 4,227,992. The above-identified disclosures are incorporated herein by reference.
Conversion of lower olefins, especially propene and butenes, over H-ZSM-5 is effective at moderately elevated temperatures and pressures. The conversion products are sought as liquid fuels, especially the C 5 + aliphatic and aromatic hydrocarbons. Olefinic gasoline is produced in good yield by the MOGD process and may be recovered as a product or recycled to the reactor system for further conversion to distillate-range products.
As a consequence of the relatively low reactivity of ethylene with known zeolite oligomerization catalysts (about 10-30% conversion for H-ZSM-5), distillate-mode reactor systems designed to completely convert a large ethylene component of feedstock would require much larger size than comparable reactor systems for converting other lower olefins. Recycle of a major amount of ethylene from the reactor effluent would result in significant increases in equipment size. By contrast, propene and butene are converted efficiently, 75 to 95% or more in a single pass, under catalytic conditions of high pressure and moderate pressure used in distillate mode operation. In U.S. Pat. No. 4,433,185, Tabak employs a two stage conversion process, with interstage flashing of unconverted ethene and subsequent high severity ethene conversion.
Ethylene has substantial value as a feedstock for polymer manufacture or other industrial processes, and can be recovered economically. It has been found that an olefin-to-distillate process utilizing C 2 -C 4 olefinic feedstock can be operated to prefractionate the feedstock for ethylene recovery and catalytic conversion of the C 3 + olefinic components.
Olefinic feedstocks may be obtained from various sources, including fossil fuel processing streams, such as gas separation units, cracking of C 2 + hydrocarbons, coal byproducts, alcohol conversion, and various synthetic fuel processing streams. Cracking of ethane and conversion of effluent is disclosed in U.S. Pat. No. 4,100,218 and conversion of ethane to aromatics over Ga-ZSM-5 is disclosed in U.S. Pat. No. 4,350,835. Olefinic effluent from fluidized catalytic cracking of gas oil or the like is a valuable source of olefins, mainly C 3 -C 4 olefins, suitable for exothermic conversion according to the present MOGD process. It is an object of the present invention to provide a unique prefractionation system for recovery of valuable ethylene and economic operation of an integrated MOGD type reactor system.
SUMMARY OF THE INVENTION
A novel technique has been found for separating and catalytically converting olefins in a continuous process. Methods and apparatus are provided for converting a fraction of olefinic feedstock comprising ethylene and C 3 + olefins to heavier liquid hydrocarbon product. It is an object of this invention to effect conversion by prefractionating the olefinic feedstock to obtain a gaseous stream rich in ethylene and a liquid stream containing C 3 + olefin; vaporizing and contacting the liquid stream from the prefractionating step with hydrocarbon conversion oligomerization catalyst in at least one exothermic catalytic reaction zone at elevated temperature and pressure to provide a heavier hydrocarbon effluent stream comprising heavy, intermediate and light hydrocarbons; flashing the effluent stream between the reaction zone and a first phase separation zone by reducing pressure of the effluent stream, thereby producing a first liquid effluent fraction rich in heavy hydrocarbons and a first effluent vapor stress containing intermediate and light hydrocarbons; condensing a portion of the first effluent vapor stream in a second phase separation zone to produce a second liquid effluent stream rich in intermediate boiling range hydrocarbons and a second vapor stream rich in light hydrocarbons; recycling at least a portion of the second liquid effluent stream as a liquid sorbent stream to the prefractionating step; and further reacting the recycle stream together with sorbed C 3 + olefin in the catalytic reactor system.
A continuous process has been designed to achieve these objectives for an exothermic reactor system with efficient heat exchange, product recovery and recycle system. Advantageously, exothermic heat is recovered from at least a portion of the reactor effluent and utilized to heat one or more fractionation system liquid streams, such as a sorption prefractionator reboiler stream. In a preferred embodiment, this is achieved by exchanging heat between at least a portion of hot vapor effluent from a first phase separation zone and prefractionator bottoms liquid rich in C 3 + olefin in a prefractionator absorber reboiler loop.
Typically, the olefinic stock consists essentially of C 2 -C 6 aliphatic hydrocarbons containing a major fraction of monoalkenes in the essential absence of dienes or other deleterious materials. The process may employ various volatile lower olefins as feedstock, with oligomerization of C 3 + alpha-olefins being preferred for either gasoline or distillate production. Preferably the olefinic feedstream contains about 50 to 75 mole % C 3 -C 5 alkenes.
These and other objects and features of the novel MOGD system will be seen in the following description of the drawing.
DESCRIPTION OF THE DRAWING
The drawing is a schematic system diagram showing a process equipment and flow line configuration for a preferred embodiment.
DESCRIPTION OF PREFERRED EMBODIMENTS
Various olefinic and paraffinic light hydrocarbon streams may be involved in the reactor or fractionation subsystems. An olefinic feedstock, such as C 2 -C 4 olefins derived from catalytic cracker (FCC) effluent, may be employed as a feedstock rich in ethene, propene, butenes, etc. for the process. The prefractionator/absorber unit separates the feedstock into a relatively pure ethene gas product and C 3 + liquid comprising the rich sorbent. Following reaction at elevated temperature and pressure over a shape selective catalyst, such as ZSM-5 or the like, the reactor system effluent is fractionated in a series of phase separators and distillation towers. In the examples herein fractionation sub-system has been devised to yield three main product streams--LPG (mainly C 3 -C 4 alkanes), gasoline boiling range hydrocarbons (C 5 to 330° F.) and distillate range heavier hydrocarbons (330° F + ). However, the inventive concept applies to various separatory techniques for heavy, intermediate and light hydrocarbon products, as determined by relative molecular weight or carbon number. Optionally, all or a portion of the olefinic gasoline range hydrocarbons from the phase separation units may be recycled for further conversion to heavier hydrocarbons in the distillate range. This may be accomplished by combining the recycled intermediate range hydrocarbons with C 3 + olefin feedstock in the prefractionation step prior to heating the combined streams.
Process conditions, catalysts and equipment suitable for use in the MOGD process are described in U.S. Pat. Nos. 3,960,978 (Givens et al), 4,021,502 (Plank et al), and 4,150,062 (Garwood et al). Hydrotreating and recycle of olefinic gasoline are disclosed in U.S. Pat. No. 4,211,640 (Garwood and Lee). Other pertinent disclosures include U.S. Pat. No. 4,227,992 (Garwood and Lee) and U.S. patent application Ser. No. 488,834, filed Apr. 26, 1983 (Owen et al.) , now U.S. Pat. No. 4,456,779 relating to catalytic processes for converting olefins to gasoline/distillate. The above disclosures are incorporated herein by reference.
CATALYST
The catalytic reactions employed herein are conducted, preferably in the presence of medium pore silicaceous metal oxide crystalline catalysts, such as acid ZSM-5 type zeolites catalysts. These materials are commonly referred to as aluminosilicates or porotectosilicates; however, the acid function may be provided by other tetrahedrally coordinated metal oxide moieties, especially Ga, B, Fe or Cr. Commercially available aluminosilicates such as ZSM-5 are employed in the operative embodiments; however, it is understood that other silicaceous catalysts having similar pore size and acidic function may be used within the inventive concept.
The catalyst materials suitable for use herein are effective in oligomerizing lower olefins, especially propene and butene-1 to higher hydrocarbons. The unique characteristics of the acid ZSM-5 catalyts are particularly suitable for use in the MOGD system. Effective catalysts include those zeolites disclosed in U.S. patent application Ser. No. 390,099 filed Jun. 21, 1982 (Wong and LaPierre) , now U.S. Pat. No. 4,430,516, and application Ser. No. 408,954 filed Aug. 17, 1982 (Koenig and Degnan), now U.S. Pat. No. 4,465,884 which relate to conversion of olefins over large pore zeolites. A preferred catalyst material for use herein is an extrudate (1.5 mm) comprising 65 weight % HZSM-5 and 35% alumina binder, having an acid cracking activity (α) of about 160 to 200.
The members of the class of crystalline zeolites for use in this invention are characterized by a pore dimension greater than about 5 Angstroms, i.e., it is capable of sorbing paraffins having a single methyl branch as well as normal paraffins, and it has a silica to alumina mole ratio of at least 12.
Although such crystalline zeolites with a silica to alumina mole ratio of at least about 12 are useful, it is preferred to use zeolites having higher ratios of at least about 30. In some zeolites, the upper limit of silica to alumina mole ratio is unbounded, with values of 30,000 and greater.
The members of the class of zeolites for use herein are exemplified by ZSM-5, ZSM-5/ZSM-11 intermediate, ZSM-11, ZSM-22, ZSM-23, ZSM-35, ZSM-38, ZSM-48 and other similar materials. U.S. Pat. No. 3,702,886 describing and claiming ZSM-5 is incorporated herein by reference. Also, U.S. Pat. No. Re. 29,948 describing and claiming a crystalline material with an X-ray diffraction pattern of ZSM-5, is incorporated herein by reference as is U.S. Pat. No. 4,061,724 describing a high silica ZSM-5 referred to as "silicate" in such patent. The ZSM-5/ZSM-11 intermediate is described in U.S. Pat. No. 4,229,424. ZSM-11 is described in U.S. Pat. No. 3,709,979. ZSM-23 is described in U.S. Pat. No. 4,076,842. ZSM-35 is described in U.S. Pat. No. 4,016,245. ZSM-38 is described in U.S. Pat. No. 4,046,859. The entire contents of the above identified patents are incorporated herein by reference. ZSM-48 is more particularly described in U.S. patent application Ser. No. 343,131 filed Jan. 27, 1982, now U.S. Pat. No. 4,375,573 the entire contents of which are incorporated herein by reference.
The zeolites used in additive catalysts in this invention may be in hydrogen form or they may be base exchanged or impregnated to contain a rare earth cation complement. Such rare earth cations comprise Sm, Nd, Pr, Ce and La. It is desirable to calcine the zeolite after base exchange.
The catalyst and separate additive composition for use in this invention may be prepared in various ways. They may be separately prepared in the form of particles such as pellets or extrudates, for example, and simply mixed in the required proportions. The particle size of the individual component particles may be quite small, for example from about 10 to about 150 microns, when intended for use in fluid bed operation, or they may be as large as up to about 1-10 mm for fixed bed operation. The components may be mixed as powders and formed into pellets or extrudate, each pellet containing both components in substantially the required proportions. It is desirable to incorporate the zeolite component of the separate additive composition in a matrix. Such matrix is useful as a binder and imparts greater resistance to the catalyst for the severe temperature, pressure and velocity conditions encountered in many cracking processes. Matrix materials include both synthetic and natural substances. Such substances include clays, silica and/or metal oxides. The latter may be either naturally occurring or in the form of gelatinous precipitates, sols or gels including mixtures of silica and metal oxides. Frequently, zeolite materials have been incorporated into naturally occurring clays, e.g. bentonite and kaolin.
A particularly advantageous form of the catalyst is an extruded pellet having a diameter of about 1-3 mm, made by mixing steamed zeolite crystals e.g. silica:alumina=70:1-500:1 with α-alumina monohydrate in a proportion of about 2:1 and calcining the formed material to obtain an extrudate having a void fraction of about 30-40%, preferably about 36%.
Referring to the drawing, olefinic rich feedstock is supplied to the plant through fluid conduit 1 under steady stream conditions. The olefins are separated in prefractionator 2 to recover an ethylene-rich stream 2E and liquid hydrocarbon stream 2L containing C 3 + feedstock components. This C 3 + feedstream is pressurized by pump 12 and then sequentially heated by passing through indirect heat exchange units 14, 16, and furnace 20 to achieve the temperature for catalytic conversion in reactor system 30, including plural reactor vessels 31A, B, C, etc.
The reactor system section shown consists of three downflow fixed bed, series reactors on line with exchanger cooling between reactors. The reactor configuration allows for any reactor to be in any position, A, B or C. The reactor in position A has the most aged catalyst and the reactor in position C has freshly regenerated catalyst. The cooled reactor effluent is separated by the high temperature separator (HTS) 33 and low temperature separator (LTS) 35 into light, intermediate and heavy range hydrocarbons. The intermediate range hydrocarbons are recycled to the inlet of the reactor in position A. The light and heavy hydrocarbons are further fractionated in the debutanizer 40 to provide lower aliphatic liquid and then in splitter unit 50, which not only separates the debutanizer bottoms into gasoline and distillate products, but provides additional liquid intermediate range hydrocarbon recycle.
The recycle is not only necessary to produce the proper distillate quality and yield but also limits the exothermic rise in temperature across each reactor to less than about 30° C. Change in recycle flow rate is intended primarily to compensate for gross changes in the feed non-olefin flow rate. As a result of preheat, the liquid recycle is substantially vaporized by the time it reaches the reactor inlet. The following is a description of the process flow in detail.
Sorbed C 3 + olefin combined with olefinic gasoline is pumped up to system pressure by pump 12 and is combined with intermediate range hydrocarbon recycles 35L and 50R after these streams have been pumped up to system pressure. The combined stream (C 3 + feed plus recycle) after preheat is routed to the inlet 30F of the reactor 31A of system 30. The combined stream (herein designated as the reactor feedstream) is first preheated against the effluent in exchanger 16C (reactor feed/position C reactor effluent exchanger), then against the effluent from the reactor in position B, in exchanger 16B (reactor feed/position B reactor effluent exchanger) and then against the effluent from the reactor in position C in exchanger 16C (reactor feed/position C reactor effluent exchanger). In the furnace 20, the reactor feed is heated to the required inlet temperature for the reactor in position A.
Because the reaction is exothermic, the effluents from the reactors in the first two positions A, B are cooled to the temperature required at the inlet of the reactors in the last two positions, B, C, by preheating the reactor feed. Temperature control is accomplished by allowing part of the reactor effluents to bypass exchangers 16A and 16B.
After heating part of fractionator 2 bottoms in reboiler 2R, the high temperature separator overhead is routed to the low temperature separator. Both high temperature separator bottoms, 33L after heating the deethanizer 60 bottoms in deethanizer reboiler 61, and the low temperature separator overhead, 35V enter on separate stages the debutanizer, which is operated at a pressure which completely condenses the debutanizer tower overhead 40G by cooling in condenser 44. The liquid from debutanizer overhead accumulator 46 provides the tower reflux 47, and feed to the deethanizer 60, which, after being pumped to the deethanizer pressure by pump 49 is sent to the deethanizer 60. The deethanizer accumulator overhead 35 is routed to the fuel gas system. The accumulator liquid 64 provides the tower reflux. The bottoms stream 63 (LPG product) may be sent to an unsaturated gas plant or otherwise recovered.
Under temperature control of the bottom stage of the sorption fractionator 2, the additional energy required for reboiling is provided by at least part of the debutanizer 41 bottom in the reboiler 2R. The bottoms stream 41 from the debutanizer 40 is sent then to the splitter, 50 which splits the C 5 + material into C 5 -330° F. gasoline (overhead liquid product and recycle) and 330° F. + distillate (bottoms product). The splitter tower overhead stream 52 is totally condensed in the splitter tower overhead condenser 54. The liquid from the overhead accumulator 56 provides the tower reflux 50L, the gasoline product 50P and the make-up gasoline recycle 50R under flow control and pressurized for recycle. After being cooled in the gasoline product cooler 50P, the gasoline product is sent to the gasoline pool. The splitter bottoms fraction is pumped to the required pressure pump 58 and then preheats the reactor feed stream in exchanger 14. Finally, the distillate product 50D is cooled to ambient temperature before being hydrotreated to improve its cetane number.
From an energy conservation standpoint, it is advantageous to reboil the prefractionator bottoms 2L using hot effluent vapor and debutanizer bottoms liquid. A kettle reboiler 42 containing 2 U-tube exchangers 43 in which these streams are circulated is a desirable feature of the system. Liquid from the bottom stage of sorption fractionator 2 is circulated in the shell side.
The product fractionation units 40, 50, and 60 may be a tray-type design or packed column. The splitter distillation tower 50 is preferably operated at substantially atmospheric pressure to improve separation and to avoid excessive bottoms temperature, which might be deleterious to the distillate product. The fractionation equipment and operating techniques are substantially similar for each of the major stills 40, 50, 60, with conventional plate design, reflux and reboiler components. The fractionation sequence and heat exchange features of the present system are operatively connected in an efficient MOGD system to provide significant economic advantages.
MOGD operating modes may be selected to provide maximum distillate product by gasoline recycle and optimal reactor system conditions. Operating examples are given for distillate mode operation, utilizing as the olefinic feedstock a pressurized stream olefinic feedstock (about 1200 kPa) comprising a major weight and mole fraction of C 3 = /C 4 = . The adiabatic exothermic oligomerization reaction conditions are readily optimized at elevated temperature and/or pressure to increase distillate yield or gasoline yield as desired, using H-ZSM-5 type catalyst. Particular process parameters such as space velocity, maximum exothermic temperature rise, etc. may be optimized for the specific oligomerization catalyst employed, olefinic feedstock and desired product distribution.
DISTILLATE MODE REACTOR OPERATION
A typical distillate mode multi-zone reactor system employs inter-zone cooling, whereby the reaction exotherm can be carefully controlled to prevent excessive temperature above the normal moderate range of about 190° to 315° C. (375°-600° F.).
Advantageously, the maximum temperature differential across any one reactor is about 30° C. (°TΔ50° F.) and the space velocity (LHSV based on olefin feed) is about 0.5 to 1. Heat exchangers provide inter-reactor cooling and reduce the effluent to fractionation temperature. It is an important aspect of energy conservation in the MOGD system to utilize at least a portion of the reactor exotherm heat value by exchanging hot reactor effluent from one or more reactors with the reactor feed. Optional heat exchangers may recover heat from the effluent stream prior to fractionation. Gasoline from the recycle conduit is pressurized by pump means and combined with feedstock, preferably at a mole ratio of about 1-2 moles per mole of olefin in the feedstock. It is preferred to operate in the distillate mode at elevated pressure of about 4200 to 7000 kPa (600-1000 psig).
The reactor system contains multiple downflow adiabatic catalytic zones in each reactor vessel. The liquid hourly space velocity (based on total fresh feedstock) is about 1 LHSV. In the distillate mode the inlet pressure to the first reactor is about 5500 kPa (800 psig total), with an olefin partial pressure of at least about 1200 kPa. Based on olefin conversion of 50% for ethene, 95% for propene, 85% for butene-1 and 75% for pentene-1, and exothermic heat of reaction is estimated at 450 BTU per pound of olefins converted. When released uniformly over the reactor beds, a maximum ΔT in each reactor is about 30° C. In the distillate mode the molar recycle ratio for gasoline is 1.5 based on olefins in the feedstock.
SORPTION/PREFRACTIONATOR OPERATION
The prefractionation system is adapted to separate volatile hydrocarbons comprising a major amount of C 2 -C 4 olefins, and typically contains 10 to 50 mole % of ethene and propene each. In the detailed examples herein the feedstock consists essentially of volatile aliphatic components as follows: ethene, 24.5 mole %, propene, 46%; propane, 6.5%; 1-butene, 15% and butanes 8%, having an average molecular weight of about 42 and more than 85 mole % olefins.
The gasoline sorbent is an aliphatic hydrocarbon mixture boiling in the normal gasoline range of about 50° to 165° C. (125° to 330° F.), with some amounts of C 3 -C 5 alkanes and alkenes. Preferably, the total gasoline sorbent stream to feedstock weight ratio is greater than about 3:1; however, the content of C 3 + olefinic components in the feedstock is a more preferred measure of sorbate or sorbent ratio. Accordingly, the process may be operated with a mole ratio of about 0.2 moles to about 10 moles of gasoline per mole of C 3 + hydrocarbons in the feedstock, with optimum operation utilizing a sorbent:sorbate molar ratio about 1:1 to 1.5:1.
It is understood that the various process conditions are given for a continuous system operating at steady state, and that substantial variations in the process are possible within the inventive concept. In the detailed examples, metric units and parts by weight are employed unless otherwise specified.
Olefinic feedstock is introduced to the system through a feedstock inlet 1 connected between stages of a fractionating sorption tower 2 wherein gaseous olefinic feedstock is contacted with liquid sorbent in a vertical fractionation column operating at least in the upper portion thereof in countercurrent flow. Effectively this unit is a C 2 /C 3 + splitter. Design of sorption equipment and unit operations are established chemical engineering techniques, and generally described in Kirk-Othmer "Encyclopedia of Chemical Technology" 3rd Ed. Vol. 1 pp. 53-96 (1978) incorporated herein by reference. In conventional refinery terminology, the sorbent stream is sometimes known as lean oil.
Sorption tower 2, as depicted, has multiple contact zones, with the heat of absorption being removed via interstage pump around cooling means. The liquid gasoline sorbent is introduced to the sorption tower through an upper inlet means above the top contact section. It is preferred to mix incoming liquid sorbent with outgoing splitter overhead ethylene-rich gas from upper gas outlet 2E and to pass this multi-phase mixture into an interstage phase separator, operatively connected between the primary sorption tower 2 and a secondary sponge absorber 3. Liquid sorbent from the separator is then pumped to the upper liquid inlet for countercurrent contact in a plate column or the like with upwardly flowing ethylene rich vapors. Liquid from the bottom of upper contact zone is pumped to a heat exchanger in an upper loop, cooled and returned to the tower above an intermediate contact zone, again cooled in lower loop, and returned to the tower above a lower contact zone, which is located below the feedstock inlet 1. Under tower design conditions of about 2100 kPa (300 psia), it is preferred to maintain liquid temperature of streams entering the tower from each liquid inlet at about 40° C. (100° F.). The lower contact zone provides further fractionation of the olefin-rich liquid. Heat is supplied to the sorption tower by removing liquid from the bottom via a reboiler loop, heating this stream in heat exchanger, and returning the reboiled bottom stream to the tower below the lower contact zone.
The liquid sorbate-sorbent mixture is withdrawn through bottom outlet 2L and pumped to storage or to olefins recovery or to reaction. This stream is suitable for use as a feedstock in an olefins oligomerization unit or may be utilized as fuel products. Ethylene rich vapor from the primary sorption tower is withdrawn via the interstage separator through conduit 3.
Distillate lean oil is fed to the top inlet 3 of sponge absorber 3 under process pressure at ambient or moderately warm temperature (e.g. 40° C.) and distributed at the top of a porous packed bed, such as Raschig rings, having sufficient bed height to provide multiple stages. The liquid rate is low; however, the sponge absorber permits sorption of about 25 wt. percent of the distillate weight in C 3 + components sorbed from the ethylene-rich stream. This stream is recovered from bottom outlet 3L. It is understood that the sorbate may be recovered from mixture with the sorbent by fractionation and the sorbent may be recycled or otherwise utilized. High purity ethylene is recovered from the system through gas outlet 3G and sent to storage, further processing or conversion to other products.
The sorption towers depicted in the drawing employ a plate column in the primary tower and a packed column in the secondary tower, however, the fractionation equipment may employ vapor-liquid contact means of various designs in each stage including packed beds of Raschig rings, saddles or other porous solids or low pressure drop valve trays (Glitsch grids). The number of theoretical stages will be determined by the feedstream composition, liquid:vapor (L/V) ratios, desired recovery and product purity. In the detailed example herein, 17 theoretical stages were employed in the primary sorption tower and 8 stages in the sponge absorber, with olefinic feedstock being fed between the 7th and 9th stages of the primary sorption tower.
In general, as the flow rate of lean oil increases, the ethylene recovery decreases, while the purity increases. The data for the splitter/absorber combination show that the excellent results are obtained with a gasoline mole ratio of at least 1:1 (based on C 3 + hydrocarbons). Such conditions will result in a C 2 = recovery of greater than 98%. Purity of more than 91 mole % can be achieved with a gasoline mole ratio of at least 2:1.
A preferred sorbent source is olefinic gasoline and distillate produced by catalytic oligomerization according to U.S. Pat. No. 4,211,640 (Garwood and Lee) and U.S. patent application Ser. No. 488,834, filed Apr. 26, 1983 (Owen et al), incorporated herein by reference. The C 3 + olefin and gasoline sorbate may be fed directly to such oligomerization process, with a portion of recovered gasoline and distillate being recycled to the sorption fractionation system herein.
The stream components of the olefinic feedstock and other main streams of the sorption/prefractionator unit and reactor feedstreams are set forth in Table I, based on parts by weight per 100 parts of feedstock.
TABLE I__________________________________________________________________________ Main Sponge SpongeComponent Fresh Sorption Gasoline Absorber Sorption Distillate Ethene Sorber Reactorwt. % Feed Fract. Recycle Feed Reflux Sorbent Product Bottoms Inlet__________________________________________________________________________C.sub.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0C.sub.2.sup.= 16.3 49.6 0.0 16.3 33.2 0.0 16.1 0.3 0.0C.sub.2 0.0 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0C.sub.3.sup.= 45.9 3.8 1.7 0.6 5.1 0.0 0.6 0.0 46.9C.sub.3 6.8 3.8 6.3 1.0 9.3 0.0 1.0 0.1 12.1i-C.sub.4 7.7 2.5 11.8 0.7 13.7 0.0 0.6 0.1 18.8C.sub.4.sup.= 20.0 0.3 1.7 0.1 1.9 0.0 0.1 0.0 21.7NC.sub.4 3.3 1.3 8.5 0.4 9.6 0.0 0.3 0.1 11.4i-C.sub.5 0.0 0.4 5.8 0.1 6.1 0.0 0.1 0.0 5.7C.sub.5.sup.= 0.0 0.8 12.7 0.2 13.4 0.0 0.1 0.1 12.4n-C.sub.5 0.0 0.0 0.3 0.0 0.3 0.0 0.0 0.0 0.4125-330° F. 0.0 1.3 209.6 0.4 210.6 0.06 0.0 0.4 209.3330° F.+ 0.0 0.0 16.8 0.0 16.3 3.5 0.0 3.5 16.3Stream No. 1 2E 35R 3F 2F liq 3S 3G 3L 30F__________________________________________________________________________
More than 98% of ethylene is recovered in the above example from the feedstock, and the gas product requires additional treatment to raise its purity from 91 mol % to polymer grade.
In the refining of petroleum or manufacture of fuels from fossil materials or various sources of hydrocarbonaceous sources, an olefinic mixture is often produced. For instance, in cracking heavier petroleum fractions, such as gas oil, to make gasoline or distillate range products, light gases containing ethene, propene, butene and related aliphatic hydrocarbons are produced. It is known to recover these valuable by-products for use as chemical feedstocks for other processes, such as alkylation, polymerization, oligomerization, LPG fuel, etc. Ethylene is particularly valuable as a basic material in the manufacture of polyethylene and other plastics, and its commercial value is substantially higher as a precursor for the chemical industry than as a fuel component. Accordingly, it is desirable to separate ethylene in high purity for such uses.
A typical byproduct of fluid catalytic cracking (FCC) units is an olefinic stream rich in C 2 -C 4 olefins, usually in mixture with lower alkanes. Ethylene can be recovered from such streams by conventional fractionation means, such as cryogenic distillation, to recover the C 2 and C 3 + fractions; however, the equipment and processing costs are high.
There are several reasons for not converting the ethylene to distillate and gasoline. The high pressure and low space velocity required for any significant conversion (on the order of 75 wt. %) would require a separate reactor train and at least one additional tower. This would substantially increase the capital cost of the unit. Converting the ethylene with the propylene/butylene stream would result in an ethylene conversion of about 20 wt. %. Additionally, the value of polymer grade ethylene may be much higher than the gasoline and distillate which would be produced if the ethylene were to be converted. Finally, there would be difficulty in scheduling the regeneration section to regenerate both the ethylene conversion and propylene/butylene conversion reactors.
While the invention has been described by specific examples and embodiments, there is no intent to limit the inventive concept except as set forth in the following claims.
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An improved catalytic process for converting an olefinic feedstock comprising ethylene and C 3 + olefins to heavier liquid hydrocarbon product comprising the steps of:
(a) prefractionating the olefinic feedstock to obtain a gaseous stream rich in ethylene and a liquid stream containing C 3 + olefin;
(b) vaporizing and contacting the liquid stream from the prefractionating step with hydrocarbon conversion oligomerization catalyst in at least one exothermic catalytic reaction zone at elevated temperature and pressure to provide a heavier hydrocarbon effluent stream comprising heavy, intermediate and light hydrocarbons;
(c) flashing the effluent stream between the reaction zone and a first phase separation zone by reducing pressure of the effluent stream, thereby producing a first liquid effluent fraction rich in heavy hydrocarbons and a first effluent vapor stream containing intermediate and light hydrocarbons;
(d) condensing a portion of the first effluent vapor stream in a second phase separation zone to produce a second liquid effluent stream rich in intermediate boiling range hydrocarbons and a second vapor stream rich in light hydrocarbons;
(e) recycling at least a portion of the second liquid effluent stream as a liquid sorbent stream to prefractionating step (a);
(f) further reacting the recycled gasoline together with sorbed C 3 + olefin in the catalytic reactor system of step (b).
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional Application No. 60/961,547, filed on Jul. 20, 2007. The disclosure of the above application is incorporated herein by reference in its entirety.
FIELD
[0002] The present disclosure relates to hybrid vehicles, and more particularly to smoothing non-driver-commanded engine restarts in hybrid vehicles.
BACKGROUND
[0003] The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
[0004] Referring now to FIG. 1 , a functional block diagram of a hybrid powertrain of a vehicle is presented. An engine 102 provides torque to a transmission 104 . The transmission 104 transmits torque to a driveline 106 . The engine 102 also drives and is driven by a belt alternator starter (BAS) system 110 . BAS systems may be characterized by a combination motor/generator used in place of a standard alternator and connected to the crankshaft of the engine 102 via the accessory drive belt.
[0005] The BAS 110 converts power from the engine 102 into electrical power, which may be stored in charge storage 112 . When the engine 102 is not running, the BAS 110 may use power from the charge storage 112 to drive the crankshaft of the engine 102 , and thereby propel the vehicle. The BAS 110 and the engine 102 are controlled by a hybrid engine control module (ECM) 120 . The hybrid ECM 120 receives signals from driver inputs 122 , such as an accelerator pedal, a gear shift lever, and/or a brake pedal.
[0006] When the vehicle comes to a stop, the hybrid ECM 120 may instruct the engine 102 to shut off. For example, this may be achieved by stopping fuel delivery and spark to the engine 102 . When the driver desires to start the vehicle from the stop, as indicated by lifting their foot off the brake pedal or pressing the accelerator pedal, the hybrid ECM 120 may command the engine 102 to restart. Also, the engine 102 may be commanded to start by the ECM 120 for reasons not initiated by the driver. When the engine 102 restarts, torque from the engine 102 is transmitted through the transmission 104 to the driveline 106 . If the brakes are applied during the engine 102 start, the driveline 106 is unable to rotate, and the torque is transmitted directly to the frame of the vehicle, which is experienced as a jerk disturbance by the driver.
SUMMARY
[0007] A hybrid engine control system comprises a hybrid engine control module and a torque mitigation module. The hybrid engine control module selectively stops an internal combustion engine (ICE). The hybrid engine control module selectively starts the ICE based upon driver inputs and non-driver inputs. The torque mitigation module reduces torque transfer from the ICE to a driveline while the ICE is started based upon the non-driver inputs and maintains torque transfer from the ICE to the driveline while the ICE is started based upon the driver inputs.
[0008] In other features, the torque mitigation module reduces torque transfer by commanding a reduced hydraulic pressure from a pump in a transmission. The reduced hydraulic pressure is a function of transmission oil temperature. The pump is powered by a charge storage module. The torque mitigation module reduces torque transfer by disengaging an electronically-controlled clutch in a transmission.
[0009] In further features, the torque mitigation module reduces torque transfer by selecting a higher gear in a transmission. The non-driver inputs include low state-of-charge of a charge storage module. The non-driver inputs include a demand signal from a heating, ventilation, and air-conditioning module. The driver inputs include signals from an accelerator pedal and a brake pedal.
[0010] A method comprises selectively stopping an internal combustion engine (ICE); selectively starting the ICE based upon driver inputs and non-driver inputs; reducing torque transfer from the ICE to a driveline while the ICE is started based upon the non-driver inputs; and maintaining torque transfer from the ICE to the driveline while the ICE is started based upon the driver inputs.
[0011] In other features, the reducing torque transfer includes commanding a reduced hydraulic pressure from a pump in a transmission. The reduced hydraulic pressure is a function of transmission oil temperature. The reducing torque transfer includes disengaging an electronically-controlled clutch in a transmission.
[0012] In further features, the reducing torque transfer includes selecting a higher gear in a transmission. The non-driver inputs include low state-of-charge of a charge storage module. The non-driver inputs include a demand signal from a heating, ventilation, and air-conditioning module. The driver inputs include signals from an accelerator pedal and a brake pedal.
[0013] Further areas of applicability of the present disclosure 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 disclosure, are intended for purposes of illustration only and are not intended to limit the scope of the disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The present disclosure will become more fully understood from the detailed description and the accompanying drawings, wherein:
[0015] FIG. 1 is a functional block diagram of a hybrid powertrain of a vehicle according to the prior art;
[0016] FIG. 2A is a functional block diagram of an exemplary hybrid powertrain according to the principles of the present disclosure;
[0017] FIG. 2B is a functional block diagram of another exemplary hybrid powertrain according to the principles of the present disclosure;
[0018] FIG. 3 is a graphical illustration of auxiliary oil pressure commands during a non-driver-commanded engine restart according to the principles of the present disclosure;
[0019] FIG. 4A is a flowchart depicting exemplary steps performed in control of the hybrid powertrain of FIG. 2A according to the principles of the present disclosure; and
[0020] FIG. 4B is a flowchart depicting exemplary steps performed in control of the hybrid powertrain of FIG. 2B according to the principles of the present disclosure.
DETAILED DESCRIPTION
[0021] The following description is merely exemplary in nature and is in no way intended to limit the disclosure, its application, or uses. For purposes of clarity, the same reference numbers will be used in the drawings to identify similar elements. As used herein, the phrase at least one of A, B, and C should be construed to mean a logical (A or B or C), using a non-exclusive logical or. It should be understood that steps within a method may be executed in different order without altering the principles of the present disclosure.
[0022] As used herein, the term module refers to an Application Specific Integrated Circuit (ASIC), an electronic circuit, a processor (shared, dedicated, or group) and memory that execute one or more software or firmware programs, a combinational logic circuit, and/or other suitable components that provide the described functionality.
[0023] Referring now to FIG. 2A , a functional block diagram of an exemplary hybrid powertrain is presented. The engine 102 transfers torque to a transmission 202 , which transfers torque to the driveline 106 . The transmission 202 may include a torque converter 204 , which receives torque from the engine 102 and couples the torque to a gearset 206 .
[0024] The gearset 206 transfers torque to the driveline 106 . The transmission 202 includes an oil pump 210 , which may be driven by the input to the torque converter 204 . The transmission 202 also includes an auxiliary pump 212 , which may be powered by a charge storage module 216 . The auxiliary pump 212 and the oil pump 210 provide hydraulic power to friction devices 220 of the transmission 202 .
[0025] For example only, the friction devices 220 may include clutches and/or bands. The friction devices 220 control which gear ratio is selected in the gearset 206 . For example only, the gearset 206 may be a planetary gearset. The friction devices 220 may control which components of the gearset 206 are locked to each other, to a housing of the gearset 206 , and/or to the input or the output of the gearset 206 . This controls the gear ratio of the gearset 206 .
[0026] The belt alternator starter (BAS) 110 converts power from the engine 102 into electrical power, which may be stored in the charge storage module 216 . The BAS 110 may also drive the crankshaft of the engine 102 in order to propel the vehicle when the engine 102 is not running. The BAS 110 and the engine 102 may be coupled via a front end accessory drive (FEAD) belt.
[0027] The FEAD belt may also drive an air-conditioning (A/C) compressor 230 . A heating ventilation and air-conditioning (HVAC) control module 232 controls the A/C compressor 230 . The HVAC control module 232 may control a blower motor for blowing conditioned air into the passenger compartment of the vehicle and may measure a temperature of the engine 102 and/or engine coolant. The HVAC control module 232 may use the A/C compressor 230 to provide cooled and/or dehumidified air and may use heat from the engine 102 to provide heated air.
[0028] A hybrid engine control module (ECM) 240 controls the engine 102 and the BAS 110 . When the vehicle comes to a stop, the hybrid ECM 240 may instruct the engine 102 to shut off, such as by stopping provision of fuel and spark to the engine 102 . When the driver wishes to start the vehicle from the stop, as indicated by the driver inputs 122 , the hybrid ECM 240 may instruct the engine 102 to restart. This is termed a driver-commanded engine restart.
[0029] The auxiliary pump 212 is used to pump oil to provide hydraulic pressure to the transmission 202 when the engine 102 is not running. When vehicle conditions allow, such as zero vehicle speed, brake applied and zero accelerator pedal position, the hybrid ECM 240 may instruct the engine 102 to shut off. The hybrid ECM 240 may instruct the engine 102 to shut off to improve fuel economy. When the speed of the engine 102 falls below a threshold, the hybrid ECM 240 may instruct the auxiliary pump 212 to turn on and produce a predetermined boosted pressure.
[0030] The boosted auxiliary pump pressure minimizes pressure dips during the transition between pressure being provided by the mechanically-driven oil pump 210 and being provided by the electrically-powered auxiliary pump 212 . After shut-off of the engine 102 has begun, the auxiliary pump 212 is directed to produce a steady-state pressure that is less than the boosted pressure. This transition may occur once the engine 102 has stopped rotating. Once the engine 102 is restarted and reaches a certain RPM, pressure from the auxiliary pump 212 may be reduced to zero and the auxiliary pump 212 may be turned off.
[0031] While the engine 102 is shut off, the hybrid ECM 240 may measure state of charge of the charge storage module 216 . If the state of charge of the charge storage module 216 decreases below a threshold level, the hybrid ECM 240 may instruct the engine 102 to restart. This is an example of a non-driver-commanded engine restart.
[0032] Another possible example of a non-driver-commanded engine restart is when the HVAC control module 232 requests that the engine 102 restart. For example, the HVAC control module 232 may require that more heat be generated in the engine 102 to provide heated air. The HVAC control module 232 may require that the A/C compressor 230 be powered to provide chilled and/or dehumidified air.
[0033] When the engine 102 restarts, torque transmitted through the transmission 202 to the driveline 106 may be absorbed by the frame of the vehicle because the wheels of the driveline 106 are not turning. This may be experienced by the driver as a jerk or a bump. This jerk may be expected by the driver during a driver-commanded engine restart. However, a non-driver-commanded engine restart may be surprising to the driver, and may be experienced as a quality issue.
[0034] To mitigate the feeling of jerk, the hybrid ECM 240 may instruct a torque mitigation module 250 to reduce the amount of torque coupled to the driveline 106 by the transmission 202 . In order to reduce torque transfer by the transmission 202 , the torque mitigation module 250 may temporarily allow the friction devices 220 to slip and/or instruct the gearset 206 to temporarily select a lower gear ratio.
[0035] The torque mitigation module 250 may instruct the auxiliary pump 212 to reduce hydraulic line pressure while the engine is restarted in response to a non-driver-commanded restart. With lower line pressure, the friction devices 220 will not be fully engaged and will allow slippage of components of the gearset 206 . The lower line pressure selected may be a function of transmission oil temperature. For example, the friction devices 220 may include a multi-plate wet clutch, whose capacity is affected by oil viscosity, which is a function of temperature. The lower line pressure may also prevent a hydraulic piston from fully engaging a band.
[0036] Once the engine has restarted, pressure from the oil pump 210 takes over and the auxiliary pump 212 can be powered down. Once slack in the driveline 106 is taken up by the gradual torque transfer produced by the torque mitigation module 250 , the friction devices 220 can be operated at full pressure and the gearset 206 can be returned to the desired gear.
[0037] The torque mitigation module 250 may also temporarily instruct the gearset 206 to select a lower gear ratio in order to reduce torque transfer by the transmission 202 . For example, instead of a first gear speed reduction from 3.06 to 1, an overdrive ratio of 0.70 to 1 may be selected. By lowering the gear ratio, the torque mitigation module 250 reduces the torque transferred to the driveline 106 . Once the engine 102 has restarted, the gearset can return to the first gear ratio of 3.06:1.
[0038] Referring now to FIG. 2B , a functional block diagram of another exemplary hybrid powertrain is presented. A transmission 260 includes the torque converter 204 , the gearset 206 , and the friction devices 220 . The oil pump 210 and the auxiliary pump 212 provide hydraulic power to the friction devices 220 .
[0039] An electronically-controlled clutch 262 selectively couples the gearset 206 to the torque converter 204 . Alternatively, the electronically-controlled clutch 262 may selectively couple the gearset 206 to the driveline 106 . The electronically-controlled clutch 262 is controlled by a torque mitigation module 270 .
[0040] When the hybrid ECM 240 begins a non-driver-commanded engine restart, the torque mitigation module 270 may deactivate the electronically-controlled clutch 262 . This decouples the torque converter 204 from the driveline 106 . After a predetermined delay, during which the engine 102 restarts, the torque mitigation module 270 may reengage the electronically-controlled clutch 262 . In addition, during this predetermined delay, the torque mitigation module 270 may select a lower gear ratio in the gearset 206 .
[0041] Referring now to FIG. 3 , a graphical illustration of auxiliary oil pump pressure commands during a non-driver-commanded engine restart is illustrated. Plot 302 depicts engine speed in revolutions per minute (RPM) versus time. Using the same time scale, plot 304 depicts the pressure commanded from the auxiliary pump 212 of FIG. 2A . In plot 302 , the engine RPM is first shown decreasing, indicating that the vehicle is coming to a stop.
[0042] When vehicle conditions allow, such as zero vehicle speed, brake applied, and zero accelerator pedal position, the hybrid ECM 240 may instruct the engine to shut off (prior to time 310 ). As the engine RPM decreases past a threshold, such as at time 310 , the torque mitigation module 250 may instruct the auxiliary pump 212 to provide a boost pressure. At time 312 , after the boost pressure has been applied for a predetermined interval, the torque mitigation module 250 may instruct the auxiliary pump 212 to produce a steady-state pressure, which is lower than the boost pressure.
[0043] The steady-state pressure may be maintained for the remainder of the time that the vehicle is stopped. At time 314 , the hybrid ECM initiates a non-driver-commanded restart. At approximately this time, the torque mitigation module 250 instructs the auxiliary pump 212 to produce a reduced pressure. The torque mitigation module 250 may also select a reduced gear ratio in the gearset 206 .
[0044] The value of the reduced pressure may be a function of transmission oil temperature. The reduced pressure may be calibrated so that it matches or is slightly below the pressure required to maintain clutch plates of one of the friction devices 220 in contact. The clutch therefore remains in mesh, but with little ability to transmit torque.
[0045] After a predetermined delay, such as one second, the engine is restarted at time 316 . The delay allows for the new reduced pressure and/or lower gear to decouple torque-transmitting components of the transmission. The gearset 206 may then be returned to the previously selected gear ratio. Because of the reduced pressure provided to the friction devices 220 , the torque produced by the engine restart will not be transmitted to the driveline 106 as a jerk. As the engine 102 increases in speed, the oil pump 210 will take over providing pressure to the friction devices 220 . Once the oil pump 210 is producing sufficient pressure, the auxiliary pump 212 may be powered off, as shown at time 318 .
[0046] Referring now to FIG. 4A , a flowchart depicts exemplary steps performed in control of the hybrid powertrain of FIG. 2A . Control begins in step 402 , where control determines whether an engine shut-off event has been requested. If so, control transfers to step 404 ; otherwise, control remains in step 402 . An engine shut-off may be initiated when vehicle conditions allow, such as zero vehicle speed, brake applied and zero accelerator pedal position.
[0047] In step 404 , as the engine RPM drops below a threshold value, the pressure of the auxiliary pump 212 is commanded to a boost pressure level. Control continues in step 406 , where the engine is turned off. For example, fuel and spark delivery to the engine may be halted. Control continues in step 408 , where pressure of the auxiliary pump 212 is reduced to a steady-state value.
[0048] Control continues in step 410 , where control determines whether an engine restart is desired. If so, control transfers to step 412 ; otherwise, control remains in step 410 . In step 412 , control determines whether the restart was driver-commanded. If so, control transfers to step 414 ; otherwise, control transfers to step 416 . A driver-commanded engine restart may result from the driver releasing the brake pedal or depressing the accelerator pedal.
[0049] In step 416 , pressure of the auxiliary pump 212 is reduced to a reduced pressure level. The reduced pressure level may be a function of transmission oil temperature, and may be determined from a lookup table indexed by transmission oil temperature. Control continues in optional step 418 , where the gear ratio of the gearset 206 is reduced.
[0050] Control continues in step 420 , where control waits for a predetermined delay period. The predetermined delay period may be a function of internal accumulators in the transmission, oil temperature, clutch pack size, and other factors. Control then continues in step 414 . In step 414 , the engine is restarted.
[0051] Control then continues in optional step 422 . In step 422 , the gear ratio of the gearset 206 is restored to the previous gear ratio. For example only, the gear ratio may be restored to first gear. Control then continues in step 424 , where the auxiliary pump is turned off once the oil pump 210 reaches a sufficient pressure. Control then returns to step 402 .
[0052] Referring now to FIG. 4B , a flowchart depicts exemplary steps performed in control of the hybrid powertrain of FIG. 2B . Control may be similar to that of FIG. 4A until step 412 . In step 412 , control determines whether the engine restart is driver-commanded. If so, control transfers to step 414 ; otherwise, control transfers to step 450 .
[0053] In step 450 , control disengages the electronically-controlled clutch. In this way, the torque converter 204 is decoupled from the driveline 106 . Control transfers to optional step 418 , where control may decrease the gear ratio of the gearset 206 . Control then continues in step 452 , where control waits for a predetermined delay. The predetermined delay period may be determined by the actuation time of the electronically-controlled clutch 262 .
[0054] Control then continues in step 414 , where the engine is restarted. Control then continues in optional step 422 , where the original gear ratio of the gearset 206 is restored. Control continues in step 454 , where the electronically-controlled clutch 262 is re-engaged. For example only, the electronically-controlled clutch 454 may be reengaged gradually so a sudden increase in torque to the driveline 106 does not result. Control continues in step 424 , where control turns off the auxiliary pump 212 once the pressure from the oil pump 210 has reached a sufficient level. Control then returns to step 402 .
[0055] Those skilled in the art can now appreciate from the foregoing description that the broad teachings of the disclosure can be implemented in a variety of forms. Therefore, while this disclosure includes particular examples, the true scope of the disclosure should not be so limited since other modifications will become apparent to the skilled practitioner upon a study of the drawings, the specification, and the following claims.
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A hybrid engine control system comprises a hybrid engine control module and a torque mitigation module. The hybrid engine control module selectively stops an internal combustion engine (ICE). The hybrid engine control module selectively starts the ICE based upon driver inputs and non-driver inputs. The torque mitigation module reduces torque transfer from the ICE to a driveline while the ICE is started based upon the non-driver inputs and maintains torque transfer from the ICE to the driveline while the ICE is started based upon the driver inputs. A method comprises selectively stopping an internal combustion engine (ICE); selectively starting the ICE based upon driver inputs and non-driver inputs; reducing torque transfer from the ICE to a driveline while the ICE is started based upon the non-driver inputs; and maintaining torque transfer from the ICE to the driveline while the ICE is started based upon the driver inputs.
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BACKGROUND OF THE INVENTION
[0001] The present invention relates generally to RAID data storage systems and methods, and deals more specifically with a system and method for transferring data from a secondary storage controller to a storage media after failure of a primary storage controller for said storage media.
[0002] It was previously known that data security is improved by data redundancy such as provided by RAID. RAID (redundant array of independent disks) systems are well known today, and there are several levels of RAID. To implement one of the RAID levels, a plurality of storage controllers and storage media such as a hard disk drive are connected by a shared bus interface such as a parallel SCSI bus. Alternately, the plurality of storage controllers and storage media may be connected in a dual loop using Fiber Channel Arbitrated Loop shared bus protocol. An ATA shared bus interface is also known. The SCSI and Fiber Channel shared interfaces are typically used in applications requiring high reliability such as those involving a server. The ATA interface is typically used for less secure storage media such as those for a desktop personal computer. This is because the ATA interface is lower cost than the SCSI or the Fiber Channel the interface.
[0003] [0003]FIG. 17 is a view schematically showing a RAID system using the previously known ATA interface. As shown in FIG. 17 , a storage controller 90 is connected to and manages a plurality of storage arrays 92 and 94 . Each of the arrays 92 and 94 comprises one or more storage physical media 96 such as a hard disk. The controller 90 utilizes the ATA interface 98 to record/store data on the arrays 92 and 94 . The ATA interface 98 is also coupled to a host computer 99 via a proper interface such as Fiber Channel, to exchange data with the host.
[0004] [0004]FIG. 18 is a block diagram showing in more detail the RAID system using the conventional ATA interface shown in FIG. 17. As shown in FIG. 18, the controller 90 includes a fiber channel connector 100 , fiber channel-host protocol control means 102 , a processor 104 , and a cache memory 106 connected to the processor 104 . The controller 90 communicates with another RAID system 101 or the host computer 99 via the fiber channel connector 100 . Data received by the controller 90 is converted into a proper protocol via the protocol control means 102 , and recorded in each of the storage media 96 having a proper address by the processor 104 .
[0005] As shown in FIG. 18, the conventional ATA interface 98 is connected to each of the storage media 96 via suitable connection means 108 , and manages these storage media 96 , thus enabling data transfer between the host computer and each of the storage media via the ATA interface 98 .
[0006] The ATA interface 98 may perform data transfer by use of a parallel transfer technology such as ATA/100 in view of its improved data transfer rate. Nevertheless, the ATA technology within ATA/100 has limitations. The following attempts have been made to improve the data transfer rate of the ATA. A data transfer rate having a clock frequency of 50 MHz and a maximum transfer rate of 100 Mbytes/s with a data width of 16 bits has been achieved for the ATA/ 100 interface. In order to further improve the data transfer rate, another attempt of doubling the data width to 32 bits or increasing a frequency of a strobe signal has been made. However, it has been known that the increase of the data width or the increase of the frequency of the strobe signal causes difficulties in data synchronization between signal lines, and siginficant interference/noise between the signal lines. Therefore, in the ATA interface, when the transfer rate of UltraDMAmode3 (44.4 Mbytes/s) or more is used, a connection with an 80 wire flat cable and 40 pins is used. Each pin is accompanied by a ground, and the interference between the signal lines is prevented.
[0007] In recent years, due to speedup in computer systems and an increase in the amount of data to be stored, the data transfer rate of the interface of the controller requires further improvement. Also, reliability of the data transfer from the storage controller to the storage media must be maintained. Also, the cost of the data storage system should be minimized despite the need for redundancy of data storage.
[0008] Such demands on the system will likely further increase, especially where the storage unit is separated from the server and connected to the server by the Fiber Channel as an independent storage area network (SAN), or in the case where the storage unit is connected to the server via the Ethernet(registered trademark) link for use.
[0009] Accordingly, an object of the present invention is to provide a high speed interface between the storage controller and redundant storage media.
[0010] Another object of the present invention is to provide such a high speed while maintaining a low cost and high reliability.
SUMMARY OF THE INVENTION
[0011] The invention resides in a storage control and switch unit for transferring data between a host computer and first, second, third and fourth storage media. A first storage controller (within the storage control and switch unit) has an operative point-to-point connection with each of the first and second storage media to manage arrays on the first and second storage media. The first storage controler also has an inoperative point-to-point connection to each of the third and fourth storage media. A second storage controller (within the storage control and switch unit) has an operative point-to-point connection with each of the third and fourth storage media to manage arrays on the third and fourth storage media. The second storage controller also has an inoperative point-to-point connection to each of the first and second storage media. First, second, third and fourth switches are logically interposed between the first, second, third and fourth storage media, respectively, and the first and second storage controllers to select which point-to-point connection to each storage media is operative and which point-to-point connection to the storage media is inoperative. In response to failure of one of the storage controllers, the other storage controller changes the operable switches of the one storage controller to be inoperable and changes the inoperable switches of the other storage controller to be operable. The other storage controller is granted management authority for the arrays controlled by the one storage controller before the failure. According to one feature of the present invention, each point-to-point conndction is made by a serial ATA unit.
[0012] According to another feature of the present invention, each controller implements a RAID level and each of the arrays is configured so as to enable redundant data storage. A mirror copy of each array is generated to provide the data redundancy. When one of the storage controllers fails, the switching means connects the array associated with the failed controller to the normal controller and also gives a control right for this array to the normal controller. This allows the normal controller to write the data into this storage array, assuring data redundancy. The normal controller retains management control of its original storage media/arrays.
[0013] A table may be used according to the present invention in controlling the switch in the failure mode describe above. The table includes identifiers given to each of the plurality of point-to-point controllers. Each identifier corresponds to a storage medium managed by the point-to-point controller. In the storage unit of the present invention, the plurality of point-to-point controllers may include means for detecting the failure of each of the plurality of point-to-point controllers, acquiring the identifier unique to the point-to-point controller on a side where the failure has occurred, and executing a predetermined processing for changing the management state. The change of the management state of each of the plurality of arrays may include a process to allow the point-to-point controller where no failure occurred to manage the array assigned to the point-to-point controller where the failure has occurred. In the storage unit of the present invention, it is preferable that each of the plurality of point-to-point controllers includes a serial ATA interface.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] [0014]FIG. 1 is a block diagram schematically showing a storage unit of the present invention.
[0015] [0015]FIG. 2 is a block diagram showing a constitution of the storage unit of the present invention.
[0016] [0016]FIG. 3 is a flowchart showing a write process in the storage unit of the present invention.
[0017] [0017]FIG. 4 is a flowchart showing a read process in the storage unit of the present invention.
[0018] [0018]FIG. 5 is a block diagram showing an embodiment of switching in a case where a failure occurs in a controller, according to the present invention.
[0019] [0019]FIG. 6 is a flowchart of a failure recovery process, according to the present invention.
[0020] [0020]FIG. 7 is a view schematically showing a failure detection process, according to the present invention.
[0021] [0021]FIG. 8 is a view schematically showing another failure detection process, according to the present invention.
[0022] [0022]FIG. 9 is a view showing an embodiment of a correspondence table used, according to the present invention.
[0023] [0023]FIG. 10 is a block diagram showing a constitution of drive means for driving switching means of the present invention.
[0024] [0024]FIG. 11 is a block diagram showing another constitution of drive means for driving switching means of the present invention.
[0025] [0025]FIG. 12 is a view showing an embodiment of the switching means of the present invention.
[0026] [0026]FIG. 13 is a view showing input and output status of the switching means shown in FIG. 12.
[0027] [0027]FIG. 14 is an exploded perspective view showing an embodiment of the storage unit of the present invention.
[0028] [0028]FIG. 15 is a view showing an embodiment of an information processing apparatus of the present invention.
[0029] [0029]FIG. 16 is a view showing another embodiment of the information processing apparatus of the present invention.
[0030] [0030]FIG. 17 is a view schematically showing a constitution example of a RAID system using a conventional parallel ATA interface, according to the Prior Art.
[0031] [0031]FIG. 18 is a view showing in detail the constitution example of the RAID system using the conventional parallel ATA interface, according to the Prior Art.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0032] Next, a detailed description will be made of the present invention along with a specific embodiment shown in the drawings. However, the present invention is not limited to the embodiments described below.
[0033] [0033]FIG. 1 is a view schematically showing a constitution of a storage unit 10 using a redundant storage method of the present invention. The storage unit 10 shown in FIG. 1 implements a RAID level 1, in which an array A provides a mirror copy of an array B. However, the present invention can be applied to any RAID system from RAID0 to RAID5 as well as the embodiment shown in FIG. 1. As shown in FIG. 1, the storage unit 10 of the present invention includes the arrays A and B. The array A includes a single or a plurality of storage media, and the array A can be configured as required by a host computer. The array B can also include a single or the plurality of storage media. In the embodiment illustrated in FIG. 1, the array B stores a mirror copy of the array A, thereby enabling redundant data integrity.
[0034] The storage media used with the present invention is not particularly limited, and any rewritable storage media such as a hard disk, a CD-R, a CD-RW, a DVD, and an MO can be applied. In the present invention, each of the arrays A and B can be configured as a unit which is a separate body including same storage media such as a hard disk or can be configured as a unit including the hard disk as the storage medium and a unit individually configured by including a different medium such as the MO.
[0035] The arrays A and B are connected to controllers 14 and 16 via a connection unit 12 , respectively, and transfer data in response to write and read requests from a host computer 22 a or 22 b . The controllers 14 and 16 are connected with each other by a proper bus line 18 or the like so that the controllers 14 and 16 can monitor the failure of the opposite one and can transfer data to the normal one in the event of the failure of any of the controllers 14 and 16 . In the preferred embodiment of the present invention, each of the controllers 14 and 16 includes a serial ATA (hereinafter, referred to as a SATA) interface 32 and 48 , respectively.
[0036] Specifically, the SATA 32 and 48 can comply with standards formulated by a serial ATA working group, for example, UltraSATA/1500, ATA/ATAPI-6, or any other interfaces complying such standards. The SATA standards previously known are shown in following table 1:
TABLE 1 Speed between Host (PC) and Device 150 Mbytes/s 300 Mbytes/s 600 Mbytes/s Cable/Connector Differential Differential Differential Transfer Transfer Transfer Transfer +/− 250 mV — — Voltage
[0037] The standards shown in the above table are just examples, and any equivalent transfer mode capable of realizing the equivalent data transfer rate can be employed in the controllers of the present invention.
[0038] The storage unit 10 shown in FIG. 1 is further connected to other RAID systems 20 a and 20 b and host computers 22 a and 22 b . Specifically, the host computers 22 a and 22 b can be configured by a personal computer or a work station. As the personal computer or the work station, a personal computer or a work station can be enumerated, which enables a CPU such as PENTIUM (registered trademark), PENTIUM II (registered trademark), and PENTIUM III (registered trademark) or a compatible CPU to be mounted thereon, and enables an operating system such as WINDOWS (registered trademark), WINDOWS NT (registered trademark), OS/2(registered trademark), UNIX, and Linux to operate. Moreover, as such personal computer or the work station, a personal computer or a work station can be enumerated, which includes a PowerPC (registered trademark) or a compatible CPU and enables an operating system such as OS/2 (registered trademark), AIX (registered trademark), and MacOS (registered trademark) to operate.
[0039] [0039]FIG. 2 is a block diagram showing in detail a portion of the storage unit 10 of the present invention shown in FIG. 1 including a controller. As shown in FIG. 2, the controller 14 includes a fiber channel connector 24 , a processor 26 , fiber channel-host protocol control means 28 for controlling a protocol between the fiber channel connector 24 and the processor 26 , a cache memory 30 connected to the processor 26 , the cache memory 30 storing transferred data, and a controller 14 for distributing the transferred data into the arrays A and B. The above-described connector, processor, protocol convert means are not limited to those of above-described constitutions, and can employ other components having equivalent functions.
[0040] In the particular embodiment shown in FIG. 2, the controller 14 uses a serial ATA (“SATA”) interface unit 32 . In the present invention, hereinafter, for explanation and specifically describing the present invention, the controllers 14 and 16 use the SATA. However, the present invention is not limited to the SATA interface.
[0041] In the storage unit 10 shown in FIG. 2, the above-described controller 14 and each of the arrays A and B are connected by connection means 34 including, for example, a switching means. The SATA 32 can be connected to storage media 36 a to 36 h constituting the arrays A and B via the connection means 34 . In the particular embodiment of the storage unit shown in FIG. 2, the SATA 32 is connected to the respective storage media 36 a to 36 d in a normal operation (as a primary controller) as shown by solid lines in FIG. 2 via switching means 38 included in the connection means 34 .
[0042] In the storage unit 10 of the present invention shown in FIG. 2, another controller 16 is further provided, which has a similar constitution to the controller 14 . The controller 16 also includes a fiber channel connector 40 , fiber channel-host protocol control means 42 , a processor 44 , and a cache memory 46 . In the normal state, a SATA 48 is connected to the storage media 36 e to 36 h constituting the array B via the connection means 34 and the switching means 38 (as a primary controller). As shown in FIG. 2, the storage unit 10 of the present invention can cope with the redundant storage method by constituting the so-called RAID system.
[0043] In FIG. 2, the controllers 14 and 16 are connected with each other via proper communication or connection means such as fiber channel connections 52 and 54 . Each of the controllers 14 and 16 detects a failure when the failure occurs in the other controller, and enables data on a mirror disk side to be transferred to the host computer without giving any load to the host computer. FIG. 2 shows that both the controllers 14 and 16 adequately operate. The SATA 32 manages the storage media 36 a to 36 d , and the SATA 48 manages the storage media 36 e to 37 h as shown by the solid lines.
[0044] The storage unit 10 of the present invention shown in FIG. 2 specifically includes means for detecting occurrence of the failure of each controller. When the failure occurs in each controller, the means detects the occurrence of the failure by a proper method. The processor which has detected the failure drives the switching means such that the SATA on a side of the connector where no failure occurred is connected to the storage media on a side where the failure occurred, thus recovering from the failure. The broken lines of FIG. 2 show a state that the switching means 52 is controlled by the above-described process.
[0045] [0045]FIG. 3 is a flowchart showing a process of a read operation in a case where the respective controllers controlling the arrays A and B normally operate in the storage unit 10 of the present invention. When the storage unit of the present invention normally operates, first, in step S 11 , the host computer issues a read request to a specific controller, for example, the controller 14 in the particular embodiment. In step S 12 , the processor 26 of the controller 14 having received the read request searches the cache memory 30 or the storage media 36 a to 36 d . When data to be read is held in the cache memory 30 , the processor 26 reads the data from the cache memory 30 and transfers the data to the host computer.
[0046] When the data to be read is held in any one of the storage media 36 a to 36 d , in step S 13 , it is decided whether or not the controller 14 can use the storage media. When the controller 14 can use the storage media (yes), in step S 14 , the processor 26 issues a read request to the storage medium holding the data among the storage media 36 a to 36 d . In step S 15 , the processor 26 transfers the read data to the host computer via the cache memory 30 . When the controller 14 has no storage medium or the controller 14 cannot access the storage media (no) for some reasons other than the failure of the controller 14 , for example, maintenance of the storage medium or for some reasons such as the failure of the storage media, in step S 16 , the processor 26 notifies the processor 44 to perform a read operation from any one of the storage media 36 e to 36 h in order to read a mirror copy of data managed by the controller 16 .
[0047] The processor 44 having received the notification issues a read request to the storage media 36 e to 36 h in step S 17 . In step S 18 , the processor 44 temporarily transfers and stores the read data in the cache memory 46 , and then transfers the read data to the cache memory 30 . In step S 15 , the read data held in the cache memory 30 is transferred by the processor 26 to the host computer having issued the read request, thus completing a series of read operations.
[0048] [0048]FIG. 4 is a flowchart of write operation process in a case where both controllers controlling the arrays A and B normally operates in the storage unit 10 of the present invention. In a write operation shown in FIG. 4, in step S 20 , the host computer makes a write request to the controller 14 . In step S 21 , data transferred from the host computer is temporarily held in the cache memory 30 . Thereafter, in step S 22 , it is decided whether or not the storage media managed by the controller 14 are available.
[0049] When the storage media 36 a to 36 d managed by the controller 14 are available (yes), in step S 23 , writing is performed for the storage media 36 a to 36 d from the cache memory 30 . When the storage media 36 a to 36 d are not available (no), in step S 24 , the data is transferred from the cache memory 30 to the cache memory 46 , and the processor 44 performs writing for the storage media 36 e to 36 h , thus completing a series of operations.
[0050] [0050]FIG. 5 shows a particular embodiment in which the switching means is operated for recovery from the failure when the failure occurs in the controller 16 in the storage unit 10 of the present invention. As shown in FIG. 5, it is assumed that the failure occurs in the controller 16 for some reasons and the controller 16 does not normally respond. In this stage, when the processor 26 detects the failure of the controller 16 , the processor 26 drives the switching means 38 to connect the SATA 32 to the storage media 36 e to 36 h for which the controller 16 possesses management right originally so as to allow the SATA 32 included in the controller 14 to manage the storage media 36 e to 36 h which the controller 16 should manage, and the processor 26 acquires the management right of the storage media 36 e to 36 h.
[0051] [0051]FIG. 6 is a flowchart schematically showing a recovery process in the event of the failure of each controller in the storage unit of the present invention. In the recovery process shown in FIG. 6, the failure between the controllers is monitored in accordance with a predetermined method in step S 30 , and it is decided whether or not communications between the processors are normal in step S 31 . When the communications are normal (no), in step S 32 , the usual write/read operations shown in FIGS. 3 and 4 are performed via the controller which the host computer requires.
[0052] When it is decided that the failure occurs in any one of the controllers, in step S 33 , the processor or the cache memory on the side where no failure occurred manages write data, which needs to be written temporarily during the failure. The write data can be managed by using a buffer memory provided on a host computer side, if appropriate. With regard to a method for monitoring occurrence of the failure in each controller, as described below in detail, the occurrence of the failure is judged based on a communication state between the processors or between the host computer and each controller. Thereafter, in step S 34 , the switching means 38 is operated and controlled so that the SATA 32 included in the controller on the side where no failure occurred manages all the storage media 36 a to 36 h.
[0053] Subsequently, in step S 35 , the predetermined storage medium is accessed and made to perform writing of the write data managed by the controller on the side where no failure occurred or the buffer memory of the host computer. In the present invention, by the employment of the above described recovery method, the data written from the occurrence of the failure of the controller until the recovery of the failure thereof is retained, and the data integrity can be performed at the time of the recovery while imparting redundancy.
[0054] [0054]FIG. 7 schematically shows a process in which the failure of each controller is detected based on judgment for communications between the processors and recovery is performed. As shown in FIG. 7, the host computer 22 accesses the controllers 60 and 62 which manage the arrays A and B and the storage media 58 via a network, for example, the SAN 56 . The processors included in the controllers 60 and 62 communicate with each other, and mutually monitor states of the controllers. Each of the controllers can use a table, in which an identifier of each controller and the array and the storage media managed by the identifier are registered. In the case of detecting the failure, each of the controllers can identify the array of the controller where the failure occurred and acquire the management right thereof.
[0055] As described above, each of the controllers 60 and 62 is given a unique identifier and specified by use of the identifier. Herein, description will be made by assuming that the failure occurs in the controller 60 . When the failure occurs in the controller 60 , the controller 62 instructs the processor included in the controller 62 to use or acquire an identifier ID-A of the controller 60 .
[0056] The controller 62 which was made possible to use the identifier ID-A notifies the host computer 22 that the ID-A is available. Thereafter, the host computer 22 transmits write data which is stored by that time in the buffer memory or the like prepared by the host computer 22 to the controller 62 by use of the identifier ID-A of the controller 60 . The processor and cache memory of the controller 62 write/read the received write data to/from the storage media 58 on the side which the controller 60 should originally manage.
[0057] [0057]FIG. 8 schematically shows a process that the detection of the failure of each controller shown in FIG. 6 judged based on the communication between the host computer 22 and each of the controllers 60 and 62 and then the recovery is performed. As shown in FIG. 8, the host computer 22 and each of the controllers 60 and 62 communicate with each other, and the host computer 22 always monitors whether or not communication thereof with each of the controllers 60 and 62 is possible, thus detecting the failure of each controller. In an embodiment shown in FIG. 9, description will be made for example by assuming that the failure occurs in the controller 60 .
[0058] The host computer 22 decides that the failure has occurred in the controller 60 from, for example, an event that the controller 60 does not respond to an inquiry for a predetermined period. At this point, the host computer 22 notifies the normal controller 62 of the identifier ID-A of the controller 60 which became impossible to perform the communication while allowing write data to evacuate by a proper method, and allows the controller 62 to acquire or use the identifier ID-A. The host computer 22 transfers the data to be written to only the controller 62 , which has newly acquired the identifier ID-A. The controller 62 receives, from the host computer 22 , data assigned to the identifier ID-A in addition to data of the identifier ID-B originally assigned. The controller 62 can perform writing for the arrays or the storage media corresponding to each identifier with reference to the held correspondence table. FIG. 9 shows an embodiment of the table for illustrating correspondence of the identifier assigned to each of the controllers explained in FIGS. 7 and 8, the controller specified by the identifier, a medium identifier assigned to each of the storage media constituting each of the arrays. The table shown in FIG. 9 can be held in storage means such as a memory of each processor included in each of the controllers 60 and 62 and an external ROM. The table shown in FIG. 9 can be also held in storage means properly rewritable such as the EEPROM in order to easily cope with changes in system settings, for example. The above described correspondence table may be composed of software and used by each processor.
[0059] As shown in FIG. 9, each controller sets, for example a management flag. In the normal state, by, for example, the management flag 2 , the respective controllers write/read only the data transferred by specifying an identifier originally assigned to/from the storage media managed by the controller provided with the identifier, for example, B- 1 to B- 4 . In the particular embodiment shown in FIG. 9, upon recognizing the occurrence of the failure, the processor on the side recognizing the occurrence of the failure in the other controller sets the management flag of the controller 60 having the identifier ID-A to 1 from 0. The write access to the controller 62 can be also processed with regard to the data to the identifier ID-A. In the present invention, a proper storage area such as a spare cache memory is provided in addition to the cache memories 30 and 46 . At the same time when the above described of the occurrence of the failure is recognized, each processor instructs the spare cache memory to hold the data transferred to the identifier ID-A until the recovery process is completed.
[0060] [0060]FIG. 10 is a view showing a specific embodiment in a case where the switching means 38 is operated and the management right is changed by the above described process of the present invention. As shown in FIG. 10, the processors 26 and 44 are respectively connected to input/output units 64 and 66 used as drive means for controlling the switching means 38 so as to drive the switching means 38 . In the particular embodiment of the present invention, the above described switching means 38 are loaded on, for example, a portion such as a drive carrier of the storage media connected to each of the controllers 14 and 16 .
[0061] In the present invention, as another embodiment loading the switching means, the drive means of the above described switching means may be provided on the SATA. FIG. 11 shows another embodiment of the present invention, in which the SATA 32 and 48 are respectively provided with drive means 68 a and 68 b for driving the switching means, and the instruction is issued from the drive means of the switching means to each of the switching means.
[0062] The embodiment shown in FIG. 11 will be described in more detail. For example, when the processor 26 of the controller 14 detects the failure of the controller 16 , the processor 26 issues an instruction to the SATA 32 managed by the processor 26 , by using the table shown in FIG. 9, and drives the switching means to connect the storage media 36 e to 36 h managed by the controller 16 , where the failure occurred. The processor 26 drives the switching means 38 to change the management states of the storage media, whereby the proper recovery can be performed in the event of the failure of each controller.
[0063] In the present invention, the use of the point-to-point controller including the SATA makes it possible to use the comparably simple switching means, thus achieving effective switching of the controller. Moreover, the storage unit 10 of the present invention employs the above described constitution, whereby redundancy with high reliability can be imparted, the data integrity is improved, and the information storage system of high cost performance ratio can be provided.
[0064] [0064]FIG. 12 is a view showing in detail a constitution of the embodiment of the switching means 38 used in the present invention. In the particular embodiment of the present invention, as described above, the switching means 38 shown in FIG. 12 can be provided in the connector means 34 for connecting each of the storage media and each of the controllers or provided in the SATAs 32 and 48 included in the controllers. In FIG. 12, reference symbols TX 0 and RX 0 indicate ports managed by one SATA, and reference symbols TX 1 and RX 1 indicate ports managed by the other SATA. In the normal operation, for example, the port TXO and the port RX 1 are connected to the different SATA, so that write/read operations can be performed for the storage media via ports TX and RX.
[0065] The particular embodiment of the present invention will be described in more detail. When failure occurs in the controller managing the port TX 0 and the port RX 0 , the drive means of the switching means included in the input/output unit or the SATA which has received a notification of the occurrence of the failure from the processor issues a select signal SEL and an enable signal EN to the switching means 38 . The select signal SEL and the enable signal EN are inputted to the switching means 38 , and drives the switching means 38 to switch a path to the side of the controller normally operating and establish a path via the TX or the RX, thus transferring the management right. FIG. 13 shows status of the enable signal EN, status of the select signal SEL, and connection status of the port TX. In FIG. 13, reference symbol HZ denotes high impedance state.
[0066] As shown in FIG. 13, for example, the port TX is switched to the port TX 0 or the port TX 1 in accordance with the status of the enable signal EN and the select signal SEL, and can be controlled by any one of the controllers. In the present invention, as shown in FIG. 13, the switching can be essentially performed only by the select signal SN. As shown in FIG. 13, use of the select signal SEL in a state where the select signal SEL is superposed on the enable signal EN makes it possible to perform the switching by selectively utilizing the high impedance state, and hence maintenance such as a hot swap in which the corresponding storage medium or the like is replaced with new one is made possible while keeping the system driven.
[0067] [0067]FIG. 14 is an exploded perspective view showing the storage unit 10 of a particular embodiment of the present invention. The storage unit 10 of the present invention can be preferably used for constituting the RAID system, for example in the information storage system such as the storage area network (SAN). In the embodiment shown in FIG. 14, the storage unit 10 of the present invention includes a case 70 , storage media 72 held in the case 70 such as the hard disk drive, power supply units 74 a and 74 b for driving the storage media 72 and supplying necessary power to the storage unit 10 , controllers 76 a and 76 b provided with correspondence to the arrays for controlling the arrays, the arrays constituting the RAID system composed of the storage media 72 , and a connector unit 80 including switching means for switching the controllers 76 a and 76 b.
[0068] The controllers 76 a and 76 b are connected to a not-shown host computer, and data transfer between the host computer and each of the storage media 72 is made possible. According to the present invention, when a failure occurs in each controller, the connector unit 80 can allow the normal controller to manage all the storage media 72 .
[0069] [0069]FIG. 15 is a view showing an embodiment in a case where the information processing apparatus is constituted by connecting the storage unit 10 of the present invention and information processing means such as a host computer. In the information processing apparatus shown in FIG. 15, a host computer 82 and a storage unit 84 of the present invention are connected by use of, for example a fiber channel hub 86 . The host computer 82 and the storage unit 84 are configured to enable mutual data transfer between the host computer 82 and the storage unit 84 .
[0070] In FIG. 15, if the fiber channel hub 86 is configured as a fiber channel switch, the storage unit 84 can be configured as a storage area network (SAN). Moreover, the host computer 82 shown in FIG. 15 can be configured as a stand-alone computer and furthermore configured as a server providing information for client computers via a network such as the Ethernet (registered trademark).
[0071] [0071]FIG. 16 shows another embodiment of the information processing apparatus of the present invention. In the embodiment shown in FIG. 16, each of two controllers included in the storage unit 84 is connected to host computers 82 a and 82 b via the fiber channel hub 86 , thus constituting the RAID system of a redundancy method using clustering. In the present invention, as shown in FIG. 16, the above described recovery method can be configured by using a plurality of information processing means such as host computers and a plurality of controllers. In the embodiment shown in FIG. 16, the detection of the failure of each controller can be achieved by monitoring communication between the controllers. Alternatively, the embodiment can employ a constitution that each of the host computers monitors the controller managed by the host computer itself and in the event of the failure, the host computer makes an instruction to the normal controller side.
[0072] Description has been heretofore made on the present invention based on the embodiments shown in the drawings. However, the present invention is not limited to the embodiments shown in the drawings. As long as the switching means can properly perform switching of the arrays, the switching means can be configured as an input/output unit on a substrate constituting the controller, or can be modularized on a substrate constituting the SATA. Moreover, the switching means can be arranged on a drive carrier for mounting the hard disk drive, and furthermore can be arranged on any other components.
[0073] Although the preferred embodiment of the present invention has been described in detail, it should be understood that various changes, substitutions and alternations can be made therein without departing from spirit and scope of the inventions as defined by the appended claims.
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A storage control and switch unit for transferring data between a host computer and first, second, third and fourth storage media. A first storage controller has an operative serial ATA connection with each of the first and second storage media and an inoperative serial ATA connection to each of the third and fourth storage media. A second storage controller has an operative serial ATA connection with each of the third and fourth storage media and an inoperative serial ATA connection to each of the first and second storage media. First, second, third and fourth switches are logically interposed between the first, second, third and fourth storage media, respectively, and the first and second storage controllers to select which serial ATA connection to each storage media is operative and which is inoperative. In response to failure of one of the storage controllers, the other storage controller changes the operable switches of the one storage controller to be inoperable and changes the inoperable switches of the other storage controller to be operable. The other storage controller is granted management authority for the arrays controlled by the one storage controller before the failure.
Disclosed is a storage unit provided with redundancy, an information processing apparatus including the same, and a recovery method of an information storage system. A storage unit of the present invention includes a plurality of arrays, each including at least one storage medium; point-to-point controllers, each of which manages the corresponding one of the plurality of arrays and communicates with the same, each of point-to-point controllers being connectable to all the storage medium; switching means for switching the point-to-point controllers, each managing the arrays; means for detecting a failure of each point-to-point controller; and means for driving the switching means in response to detection of the failure of each controller. The storage unit changes management states of arrays in response to the detection of a failure.
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This application is a division, of application No. 07/884,185, filed May 18, 1992, now U.S. Pat. No. 5,322,228.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a screening method for conducting tensile strength tests of an optical fiber a wire or the like by applying a load thereto and an apparatus for carrying out the method.
2. Description of the Related Arts
In the manufacturing line of an optical fiber, in order to guarantee the breakage longevity of the optical fiber, a proof test is conducted. In the test, a weak portion of the optical fiber is broken and removed by applying a certain tensile force to a part of the manufacturing line. The test is conducted by using a screening apparatus.
A conventional screening apparatus is described below with reference to FIGS. 16 and 17. FIG. 16 shows a schematic construction of the conventional screening apparatus. FIG. 17 is a sectional view taken along a line 17--17 of FIG. 16.
The apparatus comprises a feeding roll 1 for feeding out a drawn optical fiber 2; a capstan wheel 3, around which the optical fiber 2 is wound, for supporting the optical fiber 2 by means of a capstan belt 4; a screening roll 5; a tension roll 6; a winding roll 7 for winding the optical fiber 2 to which tension has been applied by a torque between the capstan wheel 3 and the screening roll 5; an arm type feeding dancer 8 provided between the feeding roll 1 and the capstan wheel 3; an arm type winding dancer 9 disposed between the tension roll 6 and the winding roll 7. The feeding dancer 8 and the winding dancer 9 absorb the fluctuation of speed and tension of the optical fiber 2 between the capstan wheel 3 and the feeding roll 1 and between the capstan wheel 3 and the winding roll 7.
According to the screening apparatus, the optical fiber 2 is fed out from the feeding roll 1 and tension is applied thereto between the capstan wheel 3 and the screening roll 5, then, wound around the winding roll 7. The line speed is determined by the drive of the capstan wheel 3. The feeding dancer 8 and the winding dancer 9 absorb the fluctuation of speed and tension between the capstan wheel 3 and the feeding roll 1 and between the capstan wheel 3 and the winding roll 7. Tension is applied to the optical fiber 2 between the capstan wheel 3 and the screening roll 5, and the optical fiber 2 is broken at a low strength portion thereof. Thus, the low strength portion of the optical fiber 2 is not wound around the winding roll 7.
Owing to the screening test, the low strength portion of the optical fiber 2 is not wound around the winding roll 7. But it is necessary to manually install the optical fiber 2 on the path line again. Japanese Patent Laid-Open Publication No. 62-91441 discloses that the optical fiber can be manually mounted on a path line easily by reciprocating a guide roller during drawing process which is required to be continuously operated for a certain period of time.
According to the conventional screening apparatus, the low strength portion of the optical fiber 2 is not wound around the winding roll 7 because the optical fiber 2 is broken at a low strength portion thereof owing to the screening test. But winding operation is suspended when the optical fiber 2 is broken. Therefore, it is necessary to mount the optical fiber 2 on the path line manually when the optical fiber 2has been broken. It is necessary to automatically mount the optical fiber 2 on the complicated path line by gripping the optical fiber 2 after it is broken at the low strength portion. It is particularly difficult to automatically mount the optical fiber 2 on the winding dancer 9 because the optical fiber 2 needs to be turned plural times as shown in FIG. 17 so as to absorb the fluctuation of the speed and tension of the optical fiber.
In addition, it is necessary to suspend the operation or manually rewind the optical fiber in a subsequent process in order to remove a defective portion other than the low strength portion, such as a random thickness, a bubble-mixed portion, a different-diameter portion or an abnormal projection. Thus, the operation is inefficiently performed.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a screening method for automatically mounting an optical fiber on the path line thereof with ease after it has been broken at a weak portion thereof and an apparatus for carrying out the method.
In accomplishing this and other objects, there is provided an apparatus for automatically screening an optical fiber having: a capstan wheel around which the optical fiber is wound; a winding roll around which the optical fiber fed out from the capstan wheel is wound; a screening roll for breaking and removing a weak portion of the optical fiber by applying tensile force between the capstan wheel and the winding roll; and a plurality of dancer rolls, disposed between the screening roll and the winding roll, for absorbing the fluctuation of the feed-out speed of the optical fiber and tensile force applied thereto due to the pivotal motion of an arm. In the above apparatus, as an improved construction, there is a sucking device, disposed downstream of tile capstan wheel in the transporting direction of the optical fiber, for sucking the optical fiber when tile optical fiber is broken; stopping means for stopping the operation of the Capstan wheel when the optical fiber is broken; and automatic transporting/mounting means for transporting the succeeding portion of the optical fiber to the winding roll when the operation of the capstan wheel is stopped as a result of the breakage of the optical fiber.
In the above construction, a plurality of dancer rolls are provided in a pivotal axial direction of the arm; a plurality of supporting rolls for applying tensile force to the optical fiber are provided between the screening roll and one of the dancer rolls and between the dancer rolls adjacent to each other; and at least a part of the supporting rolls is movable between the path line of the optical fiber and the move-away position thereof.
In the above construction, there are provided detecting means for detecting a defective portion of the optical fiber; and cutting means, disposed downstream of the capstan wheel in the transporting direction of the optical fiber, for cutting the optical fiber at a defective portion thereof based on information supplied by the detecting means when the defective portion of the optical fiber is passing the cutting means.
In the above construction, the automatic transporting/mounting means comprises gripping means for gripping the succeeding portion of the optical fiber; and the gripping means has a hand of opening/closing type for gripping the optical fiber.
In the above construction, the automatic transporting/mounting means comprises gripping means for gripping the succeeding portion of the optical fiber; and the gripping means has a sucking/holding device for sucking and holding the optical fiber.
In the above construction, the automatic transporting/mounting means comprises gripping means for gripping the succeeding portion of the optical fiber; and the gripping means has a pair of rotatable rolls for holding the optical fiber therebetween by applying tensile force thereto.
In the above construction, a capstan belt which is rotatable is provided in contact with the capstan wheel and a feeding dancer which is pivotal is provided upstream of the capstan belt is at the move-away position and the feeding dancer absorbs the speed fluctuation of the optical fiber when the automatic transporting/mounting means transports the optical fiber as the result of breakage of the optical fiber.
According to the above construction, when an optical fiber has been broken, the low-strength portion thereof is sucked by the sucking device and the drive stopping means stops the capstan wheel and the line stops. As a result, the automatic transporting/mounting means transports the succeeding portion of the optical fiber to the winding roll. The dancer rolls disposed in the axial direction of the pivotal arm reciprocates the supporting rolls, which eliminates a complicated winding of the optical fiber on the dancer rolls. In addition, the detecting means detects defects of the optical fiber which is cut by the cutting means. Therefore, defective portions of the optical fiber are prevented from being wound around the winding roll.
In a method for screening an optical fiber in which a screening roll for breaking and removing a low strength portion of the optical fiber by applying tensile force thereto is disposed between a capstan wheel around which the traveling optical fiber is wound and a winding roll around which the optical fiber fed out from the capstan wheel is wound; and a first sucking device and a second sucking device are disposed downstream of the capstan wheel and upstream of the winding roll, respectively. The method comprises the steps of: stopping the travel of the optical fiber when the optical fiber has been broken; operating the first and second sucking devices so that the first sucking device grips one end portion of the optical fiber disposed downstream of the capstan wheel; and the second sucking device grips the other end portion of the optical fiber disposed upstream of the winding roll; keeping the second sucking device operating so that the second sucking device processes the other end portion of the optical fiber wound around the winding roll; and stopping the first sucking device so that the one end portion of the optical fiber is released from the first sucking device and installed on the path line of the optical fiber and the one end portion of the optical fiber is installed on the winding roll.
According to the method, when an optical fiber has been broken, the low-strength portion thereof is sucked by the first and second sucking devices and the capstan wheel is stopped and the manufacturing line stops. While the second sucking device grips an end portion of the optical fiber with tensile force applied thereto, the end portion of the optical fiber is automatically processed. On the first sucking device, the automatic transporting/mounting device transports the succeeding portion of the optical fiber to the winding roll. Thus, the screening operation is resumed.
According to another preferred embodiment, there is provided an apparatus for sucking an optical fiber having a sucking nozzle disposed downstream of a capstan wheel around which the traveling optical fiber is wound, in which a sucking opening of the sucking nozzle is disposed in the movable range of the path line of the optical fiber which changes according to the travel speed of the optical fiber.
According to another preferred embodiment, there is provided an apparatus for sucking an optical fiber having a sucking nozzle disposed downstream of a capstan wheel around which the traveling optical fiber is wound, in which the sucking nozzle is disposed alongside of the path line of the optical fiber; and an opening of the sucking nozzle is positioned to be perpendicular to the path line.
According to the above construction, when an optical fiber traveling at a high speed has been broken, the optical fiber fed out from the capstan wheel is sucked by the sucking device. Since the sucking nozzle is positioned in the movable range of the path line of the optical path, the broken optical fiber can be reliably sucked even though the travel speed of the optical fiber changes. Further, since the sucking nozzle is disposed alongside of the path line of the optical fiber, the leading end of the optical fiber can be easily mounted on the line and the broken optical fiber can be easily collected.
According to another preferred embodiment, there is provided an apparatus for continuously winding an optical fiber comprising: a winding reel, rotatably supported, for winding the optical fiber; a guide roller disposed in the vicinity of the winding reel and supported to be movable in a direction along the shaft of the winding reel; a cutter for cutting the optical fiber ; and a tape sticking device for retaining end portion of the optical fiber which has been cut on the winding reel.
In the above construction, a slit is formed on a flange of the winding reel; and a detecting means for detecting the position of the slit is formed so that the optical fiber is inserted through the slit at a predetermined rotational position winding reel; and the end portion of the optical fiber is retained on the outer surface of the flange by means of a tape.
According to the above construction, the tape sticking device fixes the end portion of the optical fiber to the surface of the winding reel and as such, the optical fiber wound around the winding reel does not loosen during transportation. Thus, the optical fiber is prevented from being damaged. The end portion of the optical fiber is retained with a tape on the outer surface of the flange. Thus, the end portion of the optical fiber can be easily processed.
According to another preferred embodiment, there is provided a winding reel for winding an optical fiber around a drum thereof comprising: two slits provided on a flange of the winding reel, in which tile length of one of the two slits is substantially equal to tile distance obtained by subtracting the radius of the drum of the winding reel from the radius of the flange; and the bottom end of the other slit does not reach the cylindrical surface obtained when the optical fiber is wound around the drum to the maximum.
In the above construction, the line connecting the one slit and the center of the flange with each other makes an angle 90° or more with the line connecting the other slit and the center of the flange with each other.
In the above construction, the outer surface of the flange is smooth.
In the above construction, two slits are formed on a flange dividing the drum into a lead winding portion for winding the forward end of the optical filer and a portion for winding the optical fiber are provided on a flange; and the diameter of a flange disposed at an outer end of the lead winding portion is smaller than that of the flange dividing the drum into the lead winding portion and the portion for winding the optical fiber.
According to the above construction, tape-sticking position can be easily set. Therefore, the end portion of the optical fiber can be easily processed. In addition, the forward end and backward end of the optical fiber are locked on the same plane and the backward end thereof can be locked at the same position irrespective of the length of the optical fiber which has been wound around the drum of the winding reel.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other objects and features of the present invention will become clear from the following description taken in conjunction with the preferred embodiments thereof with reference to the accompanying drawings, in which:
FIG. 1 is a schematic construction view showing an automatic screening apparatus, according to an embodiment of the present invention, in which an optical fiber has been broken;
FIG. 2 is a schematic construction view showing an automatic screening apparatus, as shown in FIG. 1, in which the optical fiber has been automatically mounted on the path line again;
FIG. 3 is a schematic construction view showing a gripping means according to an embodiment of the present invention;
FIG. 4 is a schematic construction view showing a gripping means according to an embodiment of the present invention;
FIG. 5 is a graph showing the relationship between the moving speed of an optical fiber and the fluctuation of tensile force applied thereto;
FIG. 6 is a schematic construction view showing an automatic screening apparatus according to an embodiment of the present invention;
FIG. 7 is a front view showing a sucking device for sucking an optical fiber according to an embodiment of the present invention;
FIG. 8 is a front view showing the sucking device shown in FIG. 7;
FIG. 9 is a side elevational view showing a continuous winding device according to an embodiment of the present invention;
FIG. 10 is a front view showing the continuous winding device shown in FIG. 9;
FIGS. 11a-11d are descriptive views showing the winding procedure;
FIGS. 12a-12b are descriptive views showing the processing of an end portion of an optical fiber;
FIG. 13 is a perspective view showing an example of a winding reel, on which an optical fiber is wound, according to the present invention;
FIG. 14 is a perspective view showing another example of a winding reel, on which an optical fiber is wound, according to the present invention;
FIGS. 15a through 15d are descriptive views showing the effect obtained by a shallow slit of a winding reel according to the present invention;
FIG. 16 is a schematic construction view showing a conventional screening apparatus; and
FIG. 17 is a sectional view taken along a line VI--VI of FIG. 16.
DETAILED DESCRIPTION OF THE INVENTION
Before the description of the present invention proceeds, it is to be noted that like parts are designated by like reference numerals throughout the accompanying drawings.
FIGS. 1 and 2 show a schematic construction of an automatic screening apparatus according to an embodiment of the present invention. FIG. 1 shows a state in which an optical fiber has been broken. FIG. 2 shows a state in which the optical fiber is automatically mounted on the path line again.
The automatic screening apparatus comprises a feeding roll 11 for feeding out a drawn optical fiber 12; a capstan wheel 13, for winding the optical fiber 12 around it, which is driven or stopped and supports the optical fiber 12 in cooperation with a capstan belt 14 capable of moving away from the capstan wheel 13 as shown in FIG. 2. The apparatus further comprises a screening roll 15; a tension roll 16; a winding roll 17 for winding around it the optical fiber 12 to which tension has been applied by torque between the capstan wheel 13 and the screening roll 15; and an arm type feeding dancer 18 disposed between the feeding roll 11 and the capstan wheel 13.
A winding dancer 19 is disposed between the tension roll 16 and the winding roll 17. The winding dancer 19 comprises a pivotal arm 20 and dancer rolls 21, 22, and 23 mounted on the arm 20 and spaced from L 1 , L 2 , and L 3 , respectively, from the pivotal center of the arm 20. Supporting rolls 24, 25, 26, 27, and 28 are disposed between the capstan wheel 13 and the screening roll 15, between the screening roll 15 and the tension roll 16, between the tension roll 16 and the dancer roll 21, between the dancer roll 21 and the dancer roll 22, and between the dancer roll 22 and the dancer roll 23, respectively. The supporting rolls 24, 25, 26, 27, and 28 are reciprocative between the path line of the optical fiber 12 and the move-away position thereof. That is, they are capable of moving upward from the move-away position thereof.
A first sucking nozzle 31-1 for sucking the optical fiber 12 which has been broken is disposed downstream of the capstan wheel 13 in the transporting direction of the optical fiber 12. The sucked optical fiber 12 is accommodated in an accommodating box 32.
A second sucking nozzle 31-2 for sucking the optical fiber 12 and an unshown box for accommodating the sucked optical fiber 12 are disposed upstream of the winding roll 17. An automatic fiber transporting/mounting means 35 comprises a crossfeed device 36 for transporting the succeeding portion of the optical fiber 12 from the capstan wheel 13 to a position above the winding roll 17 and a transporting/mounting device 37 for transporting the optical fiber 12 from the position above the winding roll 17 to the winding roll 17 and mounting it on the winding roll 17. The crossfeed device 36 and the transporting/mounting device 37 are supported by a guide rail 38 and a guide rail 39, respectively. A cutter 40 for cutting the optical fiber 12 is supported by the guide rail 39. A tape sticking device 41 fixes an end portion of the optical fiber 12 to the outer surface of flange of the winding roll 17.
The crosssfeed device 36 and the transporting/mounting device 37 are provided with a gripping means 71 for gripping the succeeding portion of the optical fiber 12. The gripping means 71 comprises a pair of hands 72 of opening/closing type. The hands 72 closes to sandwich the optical fiber 12 therebetween. An unshown motor drives the gripping means 71 to travel along the guide rails 38 and 39.
Another embodiment of the present invention is described below with reference to FIGS. 3 and 4.
A gripping means 151 shown in FIG. 3 comprises a sucking nozzle 152 for sucking the optical fiber 12 with a constant sucking force, for example, 20g and holding it. A motor 153 drives the gripping means 151 to travel along the guide rails 38 (39).
A gripping means 162 shown in FIG. 4, comprising a pair of pinch rollers 164 driven by a torque motor 163 with a constant torque, holds the optical fiber 12 sandwiched between the pinch rollers 164 by applying a constant tensile force to the optical fiber 12. A motor 165 drives the gripping means 162 to travel along the guide rail 38 (39). In the gripping means 162, the pinch rollers 164 are driven by the torque motor 163 at a constant torque irrespective of the travel speed of the motor 165. Thus, the optical fiber 12 is held with a constant tensile force applied thereto.
The operation of the automatic screening apparatus of the above-described construction is described below.
Supposing that tensile force applied to the optical fiber 12 at the feeding roll 11 is smaller than 100gr and that tensile force of 700g is applied to the optical fiber 12 between the capstan wheel 13 and the screening roll 15. If the optical fiber 12 has a low strength portion, the optical fiber 12 is broken between the capstan wheel 13 and the screening roll 15. Referring to FIG. 1, when the optical fiber 12 is broken, the reduction of the tensile force of the automatic system is detected. As a result, the sucking nozzle 31-1 starts sucking the optical fiber 12. The sucking nozzle 31-1 reduces the pressure of the suction side by blowing pressurizing air of 5Kg/cm 2 to the discharge side, thus sucking the optical fiber 12 traveling at a speed of 800m/min. While the sucking nozzle 31-1 is sucking the optical fiber 12, the speed of the feeding roll 11 and that of the capstan wheel 13 decrease and stop. At this time, the sucking nozzle 31-2 is operated and the end portion of the optical fiber 12 is processed.
The operation for processing the end portion of the optical fiber 12 is carried out as follows. First, the tape sticking device 41 fixes the optical fiber 12 to the flange of the winding roll 17. Then, the optical fiber 12 is cut by the cutter 40. The optical fiber 12 thus cut is sucked by the sucking nozzle 31-2 and accommodated in the accommodating box. Thereafter, the operation of the sucking nozzle 31-2 is stopped. Then, the winding roll 17 is replaced with another winding roll that is vacant of the optical fiber 12. These operations are called processing of the end portion of the optical fiber 12. The arm 20 of the winding dancer 19 is fixed at a horizontal position and the supporting rolls 24, 25, 26, 27, and 28 move to the highest position to prepare an automatic fiber installation. Upon stop of the capstan wheel 13, the succeeding portion of the optical fiber 12 is gripped by the hand 72 of the gripping means 71 of the crosssfeed device 36 between the capstan wheel 13 and the sucking nozzle sucking nozzle 31-1. Upon upward movement of the capstan belt 14, the feeding roll 1 feeds out the optical fiber 12. The gripping means 71 travels along the guide rail 38 of the crosssfeed device 36, thus transporting the optical fiber 12 to the position above the winding roll 17.
Thereafter, the supporting rolls 24 through 28 move downward sequentially in the order from the supporting roll 24 to the supporting roll 28, thus forming the path line of the optical fiber 12. The optical fiber 12 which has been gripped by the gripping means 71 of the crosssfeed device 36 is gripped by the gripping means 71 of the transporting/mounting device 37 above the winding roll 17. As a result, the gripping means 71 of the transporting/mounting device 37 moves downward along the guide rail 39. Then, the end portion of the optical fiber 12 is fixed to the winding roll 17 vacant of the optical fiber 12. Thereafter, the capstan belt 14 moves downward, thus supporting the optical fiber 12 on the capstan wheel 13. At this time, the arm 20 of the winding dancer 19 is allowed to be pivotal. Thus, the automatic fiber installing operation is completed.
When the moving speed of the gripping means 71 changes during the transportation of the optical fiber 12, the feeding dancer 18 pivots because the capstan belt 14 is at the move-away position. Thus, the rotational speed of the feeding roll 11 is adjusted. As a result, the fluctuation of the moving speed of the gripping means 71 is absorbed and consequently, the optical fiber 12 being transported has a constant tensile force.
Experiments for installing the succeeding portion of the optical fiber 12 on the path line were carried out by using the above-described screening apparatus at a moving speed of 800m/min. The diameter of the first sucking nozzles and that of the second sucking nozzle were 20mm; air consumption was 0.6m 3 /min; and the highest wind speed in the sucking nozzles was 100m/sec. Fiber waste of approximately 4000m collected during 10 times of operation for installing the succeeding portion of the optical fiber 12 on the path line was accommodated in the accommodating box of 500mm 3 . On the second sucking side, the optical fiber 12 traveled about 4m after it was broken. The second sucking nozzle was 8m distant from the broken position of the optical fiber 12. Therefore, about 4m of the optical fiber 12 was sucked by the second sucking nozzle. The length of the second sucking nozzle was lm. Of 1m, 0.7m was necessary for processing the end portion of the optical fiber 12. The force for sucking the optical fiber 12 was 30gf. The optical fiber 12 was not loosened during the processing of the end portion of the optical fiber 12. Fiber waste could be sucked. The succeeding optical fiber 12 could be automatically installed on the path line in experiments conducted 10 times in these condition.
As apparent from the foregoing description, the second sucking device and the tape sticking device are provided in addition to the first sucking device. Thus, the succeeding optical fiber can be automatically installed on the path line after it is broken. The apparatus may be applied to a drawing apparatus. In addition, the apparatus may be utilized to detect defects of a fiber, namely, whether or not the outer diameter of the fiber is the same throughout its length or resin has been applied uniformly throughout its length and remove a wrong portion.
Comparison is made between the performance of the conventional winding dancer 9 (FIGS. 16 and 17) and that of the winding dancer 19 of the present invention. Angle change in the conventional dancer 9 necessary for absorbing the fluctuation of a length L is
.increment.θ=L/6L
where L is the distance between the pivotal center and the dancer roll. Angle change in the dancer 19 of the present invention necessary for absorbing the fluctuation of a length L is
.increment.θ=L/2(L.sub.1 +L.sub.2 +L.sub.3)
Accordingly, a sufficient absorption capability can be obtained by making the distances L 1 , L 2 , L 3 between the pivotal center and each dancer rolls 21, 22, and 23 large.
The response to a slight disturbance depends on the rotational inertia of the dancer rolls 21, 22, and 23 and not so much on the rotational inertia of the arm 20. FIG. 5 shows the relationship between the moving speed of the optical fiber 12 and the fluctuation of tensile force in the conventional winding dancer 9 and the winding dancer 19 of the present invention. As shown in FIG. 5, a resonance occurs partially in the case of the winding dancer 19, which can be solved by adjusting the length of the arm 20. Resonance fluctuation is approximately 3.5g which does not differ much from that of the conventional winding dancer 9. Thus, the succeeding optical fiber 12 can be automatically installed on the path line after it is broken.
The above-described screening automatic apparatus is capable of automatically installing the succeeding optical fiber 12 while it is being moved with a constant tensile force applied thereto after it is broken.
As described above, the gripping means 51 and 62 shown in FIG. 3 and 4 have gripping operation similar to that of the gripping means 71 having the hand 72. In the case of the gripping means 62, the pair of pinch rollers 64 driven at a constant torque holds the optical fiber 12 by applying a constant tensile force thereto. Further, the fluctuation of the moving speed of the optical fiber 12 can be absorbed due to the pivotal motion of the feeding dancer 18 while the gripping means 62 is transporting the optical fiber 12 along the guide rail. Therefore, a constant tensile force can be reliably kept to be applied to the optical fiber 12.
Referring to FIG. 6, an embodiment of the present invention is described below. There are provided, between the feeding roll 11 and the capstan wheel 13, a dice 41 for applying ink to the optical fiber 12; an ultraviolet ray irradiating oven 42 for hardening the ink applied to the optical fiber 12; a monitor 43 for detecting a portion if the outer diameter thereof is different from the outer diameter of the optical fiber 12; and a detecting device 44 for detecting a projection formed on the optical fiber 12. A cutter 45 is disposed between the capstan wheel 13 and the sucking nozzle 31. The cutter 45 is driven based on a signal outputted from the monitor 43 and the detecting device 44. The cutter 45 is also driven by information indicating the existence of an irregular portion of the optical fiber 12 and bubble-mixed portion formed during drawing operation.
According to the apparatus of the above construction, ink applied by the dice 41 to the optical fiber 12 fed out from the feeding roll 11 is hardened by the ultraviolet ray irradiating oven 42. If the optical fiber 12 has defects, i.e., if it has a portion of a different diameter or an irregular portion, the monitor 43 or the detecting device 44 detects that, thus supplying a signal indicating the defect to the cutter 45. The cutter 45 cuts the defective portion of the optical fiber 12 when it becomes opposed thereto similarly to the case in which the low strength portion is broken. Then, the defective portion is removed from the optical fiber 12 and then the optical fiber 12 automatically mounted on the path line. The data of the defective portion may be obtained during the drawing of the optical fiber 12 and a signal indicating the existence of the defective portion is sent to the cutter 45. The cutter 45 operates when the defective portion of the optical fiber 12 becomes opposed thereto. Then, similarly to the above, the optical fiber 12 is automatically mounted on the path line.
According to the apparatus of the above construction, the defective portion of the optical fiber 12 can be automatically removed according to the information supplied by the monitor 43 and the detecting device 44 in addition to the low strength portion.
According to the automatic screening apparatus of the present invention, the device for sucking the optical fiber which has been broken is provided. In addition, the automatic fiber installing means is provided to wind and transport the optical fiber which has been broken at a defective point to the capstan wheel while the operation of the capstan wheel is stopped. A plurality of dancer rolls are provided in the axial direction of the pivotal arm so as to move the supporting roll away from the path line. Thus, the automatic fiber installing means performs an easy operation.
In addition, the capstan belt is moved away from the capstan wheel so that the feeding dancer absorbs the fluctuation of the moving speed of the optical fiber during the installation of the succeeding portion of the optical fiber due to the pivotal motion of the feeding dancer. Thus, the optical fiber can be transported with a constant tensile force applied thereto.
According to the automatic screening apparatus of the present invention, means for detecting a defective portion of the optical fiber are provided so that the cutting means cuts the defective portion. That is, the defective portion of the optical fiber can be automatically removed therefrom. Consequently, it is unnecessary to suspend the operation of the line in order to remove the defective portion manually or rewind the optical fiber in the following process. Owing to this construction, the use of fewer machines for rewinding the optical fiber suffices for operation. Hence, a low cost.
A still another embodiment of the present invention is described with reference to FIGS. 7 and 8. A first capstan section of a wire drawing machine according to this embodiment comprises a first capstan wheel 13 around which the drawn optical fiber 12 is wound and rollers 14a through 14c, for guiding a first capstan belt 14, which is driven by a mechanism for driving the first capstan wheel 13. The path line L 1 of the optical fiber 12 is appropriately determined according the arrangement of these members.
According to a device for sucking the optical fiber 12 of this embodiment, a sucking nozzle is not provided concentrically with the path line of the optical fiber 12, but reliably sucks the optical fiber 12 not inserted thereinto and traveling at a high speed.
As shown in FIGS. 7 and 8, in the first capstan section, a sucking nozzle 31-1 is disposed alongside of the path line L 1 in the downstream side of the transporting direction of the optical fiber 12. The sucking nozzle 31-1 is connected with an air hose 31-b, at an intermediate portion thereof, connected with an unshown compression air source and a waste fiber accommodating box 31a at the base portion thereof. A sucking opening 31c disposed at the forward end of the sucking nozzle 31-1 is perpendicular to the path line L 1 .
The sucking nozzle 31-1 is a known one. Compressed air introduced into the intermediate portion thereof through the air hose 31-b circulates in the sucking nozzle 31-1 in the circumferential direction thereof and is rapidly blown out toward the waste fiber accommodating box 31a. Thus, ejecting effect generated by the flow of compressed air generates the force of sucking the broken optical fiber 12 into the sucking opening 31c.
Tests for investigating success percentage in sucking the broken optical fiber 12 mounted on various positions were conducted.
FIG. 7 shows the mounting position of the sucking nozzle 31-1 in conducting the sucking test. FIG. 8 shows the path line of the optical fiber 12 which travels at different speeds.
First, an investigation for finding the optimum mounting position of the sucking nozzle was conducted. In embodiment 1, as shown in FIG. 8, the sucking nozzle was disposed alongside the path line L 1 as described in the above-described embodiment. In comparison 1, a sucking nozzle is disposed coaxially with a path line as done in the conventional art. In comparison 2, the sucking nozzle was disposed below the path line. The test for examining success percentage in sucking the broken optical fiber 12 was conducted under the following condition: The diameter of the sucking nozzle was 22mm and air was fed from the air hose at a compression pressure of 5kg/cm 2 .
TABLE 1______________________________________ embodiment 1______________________________________position of sucking nozzle alongside path linedistance between path line and 10 mmsucking openingsuccession % ateach fiber speed 20 m/min 100100 m/min 100400 m/min 100800 m/min 100operation efficiency______________________________________
Test results indicate the reason the success percentage of sucking force applied from the side of the path line is higher than that applied from the lower portion of the path line as follows: That is, since the optical fiber is composed mainly of quarts glass, it is more rigid than an ordinary fiber. Therefore, when it is broken, the optical fiber does not hang vertically but takes a position as shown in FIG. 7. The optical fiber attains approximately a horizontal level as the speed of the optical fiber becomes higher. Therefore, when the opening of the sucking nozzle is disposed near and directly below the path line, the optical fiber becomes distant from the sucking nozzle when it is broken. The faster the speed of the optical fiber travels, the more distant the distance between the optical fiber and the sucking nozzle becomes, which makes it difficult for the sucking nozzle to suck the broken optical fiber. On the other hand, when the sucking nozzle is alongside of the path line, the distance between the opening of the sucking nozzle and the; path line does not change beyond the diameter of the opening of the sucking nozzle even though the travel path of the optical fiber is changed. Thus, even though the optical fiber travels at a high speed, the sucking nozzle is capable of easily sucking the broken optical fiber.
Apparently, the broken optical fiber can be sucked by the sucking nozzle even though the sucking nozzle is out of the path line by placing the sucking nozzle at a position within the movable range of the path line which changes depending on the speed of the optical fiber. Theoretically, the greater and the diameter of the opening of the sucking opening is and the shorter the distance between the opening of the sucking nozzle and the path line is, the more reliably the broken optical fiber can be sucked by the sucking nozzle in a wider range when the sucking nozzle is placed alongside the path line.
The relationship between the diameter of the opening of the sucking nozzle and success percentage of suction was examined. The diameters of the openings of sucking nozzles were 8, 22, 50, 75mm. The optical fiber traveled at a speed of 20 to 800m/min and forcibly broken with the sucking nozzles disposed alongside the path line. The sucking nozzles were conventional ones. Air pressure was 5kg/cm 2 . The result is shown in Table 2.
TABLE 2______________________________________ embodi. embodi. embodi. embodi. 2 1 3 4______________________________________diameter of sucking 8 mm 22 mm 50 mm 75 mmnozzledistance between path 10 mm 10 mm 10 mm 10 mmline and suckingopeningsuccess percentageat each speed ofoptical fiber 20 m/min 100 100 100 100100 m/min 90 100 100 100400 m/min 40 100 100 50800 m/min 10 100 70 0______________________________________
As Table 2 indicates, a sucking nozzle sucks the optical fiber most reliably when the diameter of the opening thereof ranges from 22 to 50mm. The reason success percentage decreases when the diameter of the opening of the sucking nozzle is large is as follows: According to the test, air pressure is constantly 5kg/cm 2 irrespective of the diameter of the opening. Wind speed in the sucking nozzle having a large diameter in its opening becomes relatively low. Air quantity for sucking the optical fiber is insufficient when the optical fiber travels at a high speed. It may be supposed that the optical fiber can be sucked by a sucking nozzle of a large-diameter opening by increasing the air pressure. But a large-diameter opening increases the cost of an equipment. As Table 2 shows, an opening less than 10mm is ineffective for sucking the optical fiber. Favorably, the diameter of the opening of the sucking nozzle is at least 10mm and more favorably, greater than 20mm.
The relationship between success percentage and the distance between the opening of the sucking nozzle and the path line was examined. Similarly to Embodiment 1 of Table 1, the sucking nozzle was disposed alongside the path line and the optical fiber traveled at a speed of 20 to 800m/min and was forcibly cut except that the distance between the opening of the sucking nozzle and the path line varied from 5mm to 50mm.
The result is shown in Table 3.
TABLE 3______________________________________ embodi. embodi. embodi. embodi. 5 1 6 7______________________________________distance between path 5 mm 10 mm 30 mm 50 mmline and suckingopeningsuccess percentageat each speed ofoptical fiber 20 m/min 100 100 100 100100 m/min 100 100 100 90400 m/min 100 100 90 60800 m/min 100 100 50 0______________________________________
As Table 3 indicates, if the distance between the opening of the sucking nozzle and the path line is smaller than 10mm, the broken optical could be sucked by the sucking nozzle even though the speed of the optical fiber is as high as 800/min. The shorter the distance between the opening of the sucking nozzle and the path line is, the higher success percentage is. But if the distance is very short, the sucking nozzle may contact the traveling optical fiber. As a result, the optical fiber may be damaged. Therefore, it is preferable that the distance between the opening of the sucking nozzle and the path line ranges from 5 to 10mm.
According to the sucking device of the embodiment, the opening of the sucking nozzle is disposed in the movable range of the path line which changes according to the travel speed of the optical fiber. Accordingly, the broken optical fiber can be reliably sucked by the sucking device even though the travel speed of the optical is varied.
The sucking nozzle is disposed alongside the path line and the opening of the sucking nozzle is perpendicular to the path line. Therefore, the end portion of the optical fiber can be easily mounted on the line by the sucking nozzle in a short period of time. In addition, the waste accommodating box is installed on -the sucking nozzle. Accordingly, fiber waste can be reliably collected and prevented from being scattered. Thus, the sucking device may be effectively applied to a drawing machine, a machine or rewinding machine.
FIGS. 9 and 10 show a continuous winding apparatus according to an embodiment of the present invention. FIG. 11 shows the procedure of winding an optical fiber. FIG. 12 shows the operation of processing an end portion of the optical fiber.
As shown in FIGS. 9 and 10, a winding reel 17 comprises a cylindrical winding portion 51 for winding the optical fiber 12 and flanges 52 and 53 integrally fixed to both sides of the winding portion 51. The shaft 54 of the winding portion 51 is connected with an unshown pulse motor. A guide roller 55 having a shaft perpendicular to the shaft 54 of the winding reel 17 is disposed above the winding reel 17. The guide roller 55 is moved by an unshown device in a direction along the shaft 54 of the winding reel 17.
A ball thread shaft 56 is disposed vertically alongside the winding reel 17 and rotatably supported by a frame 57. The shaft of an unshown driving motor is connected with one end of the ball thread shaft 56. A moving member 58 is screwed into the ball thread shaft 56 and moves vertically by the rotation of the ball thread shaft 56.
Referring to FIG. 9, a piston cylinder 59 having a piston rod movable toward the winding reel 17 is mounted on the moving member 58. A gripping portion 60 for gripping the optical fiber 12 and a cutter 61 for cutting it are installed on the leading end of the piston rod. After a predetermined amount of the Optical fiber 12 is wound around the winding reel 17, the piston cylinder 59 is operated. As a result, the optical fiber 12 is gripped by the gripping portion 60 and cut by the cutter 61.
A tape sticking device 62 is disposed alongside the ball thread shaft 56. The tape sticking device 62 comprises a roller 66 around which band-shaped paper 65 having a plurality of tapes 64 stuck thereto is wound; a driving roller 67 for winding the paper 65 around it; and a piston cylinder 68 for sticking the tape 64 to the end face of the flange 52 of the winding reel 17 by sucking the tape 64.
Slits 70 and 71 for taking out the end portion of the optical fiber 12 wound around the winding portion 51 are formed on the flange 52 of the winding reel 17. More specifically, the slits 70 and 71 are formed on the periphery of the flange 52 of the winding reel 17 and spaced from each other by 180°. The slit 71 is deeper than the slit 70. The forward end of the optical fiber 12 is inserted into the slit 71 and the backward end thereof is inserted into the slit 70. A photoelectric sensor 69 serving as a means for detecting the position of the slit 70 is disposed alongside the winding reel 17 and connected with a pulse motor for driving the winding reel 17.
In order to replace the winding reel 17 having a sufficient amount of the optical fiber 12 wound around it, the photoelectric sensor 69 detects the slit 71, thus outputting a signal indicating the detected result as shown in FIG. 12b. As a result, the pulse motor drives the winding reel 17 at a slight speed. As shown in FIG. 12a, when the guide roller 55 is moved from a position above the winding portion 51 shown by a solid line to a position shown by a two-dot chain line, the optical fiber 12 in sliding contact with the periphery of the flange 52 is caught by the slit 71 when the optical fiber 12 is at a predetermined position shown by a two-dot chain line of FIG. 12. Consequently, the optical fiber 12 is inserted into the slit 71. Then, the optical fiber 12 is taken out from the winding reel 17 through the slit 70.
Then, as shown in FIG. 11a, the piston cylinder 68 of the tape sticking device 62 is operated and the tape 64 is sucked. Thereafter, as shown in FIG. 12b, the tape 64 is stuck to a predetermined position of the outer surface of the flange 52 of the winding reel 17 and the backward end of the optical fiber 12 is locked at the predetermined position of the surface of the flange 52. Then, the piston cylinder 59 is operated so that the gripping portion 60 grips the optical fiber 12 and the cutter 61 cuts the gripped portion of the optical fiber 12 as shown in FIG. 11b. Then, the winding reel 17 is replaced with the winding reel 17 vacant of the optical fiber 12 by an unshown replacing device. The flange 52 of the winding reel 17 locks the optical fiber 12 by means of the tape 64 at a position 20cm distant from the backward end of the optical fiber 12 supposing that the diameter of the winding reel 17 is 40cm. Therefore, the optical fiber 12 is not an obstacle to the transportation of the winding reel 17.
The optical fiber 12 is wound around the winding reel 17 which has replaced the winding reel having the predetermined amount of the optical fiber 12 wound around it. As shown in FIG. 11b, the backward end of the cut optical fiber 12 on the guide roll 55 side is gripped by the gripping portion 60. Then, the ball thread shaft 56 is rotated in this condition to move the moving member 58 downward. As a result, as shown in FIG. 11c, the backward end of the optical fiber 12 gripped by the gripping portion 60 is pulled downward. Then, similarly to the above description, the piston cylinder 68 of the tape sticking device 62 is operated to stick the tape 64 to the predetermined position of the outer surface of the flange 52 of the winding reel 17. Then, the backward end of the optical fiber 12 is locked at the predetermined position of the flange 52.
The optical fiber 12 is released from the gripping portion 60 and the ball thread shaft 56 is rotated to be returned to the original position. The photoelectric sensor 69 detects the slit 71 and outputs a signal indicating the detected result to the pulse motor. In response to the signal, the pulse motor drives the winding reel 17 at a slight speed as shown in FIG. 12b. When the guide roller 55 is moved from the position shown by the two-dot chain line of FIG. 12a to the position above the winding portion 51 shown by the solid line of FIG. 12a, the optical fiber 12 in sliding contact with the periphery of the flange 52 is caught by the slit 70 when the slit 70 is at the predetermined position shown by the two-dot chain line of FIG. 12a. Then, the optical fiber 12 is inserted into the slit 70. As a result, the optical fiber 12 is introduced into an inner portion of the winding reel 17 through the slit 70. Thereafter, as shown in FIG. 11d, the winding reel 17 is rotated to wind the optical fiber 12 around it.
The optical fiber 12 is wound continuously around the winding reel 17 by repeating the above-described process. In this case, the forward end of the optical fiber 12 and the backward end thereof are taken out outward from the flange 52 and stuck to the predetermined position of the flange 52 with the tape 64. Thus, the end portions of the optical fiber 12 can be reliably held by the winding reel 17. The end portions of the optical fiber 12 are held by the flange 52 without using the flange 53 of the other side of the winding reel 17. Therefore, only one tape sticking device is used.
As described above, according to the continuous winding apparatus of the present invention, an optical fiber supported by the guide roller is wound around the rotatable winding reel and cut by the cutter. Then, the end portion of the optical fiber is held by the winding reel by means of the tape sticking device. Accordingly, the end portion of the optical fiber is reliably held by the winding reel and as such, the optical fiber does not become loose.
Further, slits are formed on the flange of the winding reel and the means for detecting the position of one of the slits is provided. When the winding reel is at a predetermined rotational position, the optical fiber is inserted into the slit so as to hold the end portion of the optical fiber on the outer surface of the flange by means of the tape. That is, the end portion of the optical fiber can be easily held by the apparatus of a simple construction.
FIG. 13 is a perspective view showing an example of a winding reel, for winding an optical fiber around the drum thereof, according to an embodiment of the present invention is wound.
Referring to FIG. 13, the winding reel comprises flanges 52 and 53, a drum 51, and two slits 70 and 71 formed on the flange 52. The length of the slit 71 is equal to the distance obtained by subtracting the radius of the drum 51 from the radius of the flange 52. The bottom end of the slit 70 does not reach the cylindrical surface obtained by winding the optical fiber 12 around the drum to the maximum (circumference (B)) as shown by one-dot chain line of FIG. 13.
The forward end portion 12a of the optical fiber 12 is locked at the outer surface of the flange 52 and then inserted through the slit 71. Thus, the optical fiber 12 is wound around the drum 51. The backward end 12b of the optical fiber 12 which has been wound is inserted through the slit 70 and locked also on the outer surface of the flange 52. That is, the forward end and the backward end of the optical fiber 12 are locked on the same plane. As disclosed in Japanese Patent Laid-Open Publication No. 64-38379, the approach of the slits 70 and 71 to the optical fiber 12 are detected by a sensor and then, a guide bar presses the optical fiber 12 into or from the drum 51 through the slits 71 and 70.
As shown in FIGS. 15a through 15c or FIGS. 15a through 15d, the bottom end of the slit 70 does not reach the cylindrical surface obtained by winding the optical fiber 12 around the drum to the maximum. Therefore, whether the optical fiber 12 is wound round the drum 51 in a small amount (FIG. 15c) or in a large amount (FIG. 15d), the optical fiber 12 is inserted through the slit 70 at the same position of the flange 52. Accordingly, it is unnecessary to adjust the positioning of the slit 70 later by determining the tape-sticking position at the start. That is, the ends of the optical fiber can be easily held on the winding reel 17 by only placing the tape sticking device aside the winding apparatus. The positioning of the slit 70 can be easily made by adjusting the feeding length of the tape sticking hand 64 and the position of the guide roller 55.
There is a possibility that the position at which the forward end of the optical fiber 12 is locked overlaps with the position at which the backward end thereof is locked if both positions are near. Therefore, favorably, the line connecting the slit 70 and the center of the flange 52 with each other makes an angle of more than 90° and more favorably, 180° with the line connecting the slit 71 and the center of the flange 52 with each other. In this manner, the forward end and the backward end of the optical fiber 12 do not interfere with each other. Preferably, the outer surface of the flange 52 is smooth so that the tape can be easily stuck thereto.
FIG. 14 is a perspective view showing a state in which the optical fiber 12 has been wound around the drum of a winding reel according to an embodiment of the present invention.
In a conventional winding reel, it is necessary that a portion for winding on the drum thereof the lead of the optical fiber several meters to several tens of meters is provided to evaluate the characteristic of the optical fiber 12. FIG. 14 shows a winding reel having the lead winding portion.
Two slits 70 and 71 are formed on an intermediate flange 52 dividing the drum into a portion 19 for winding the lead and a portion 20 for winding the optical fiber 12 as shown in FIGS. 13 and 14. The end portions of the optical fiber 12 are locked on the outer surface of the intermediate flange 52. In order to prevent the hand of the tape sticking device from contacting a flange 75 of the portion 19, it is desirable that the diameter of the flange 75 is smaller than that of the intermediate flange 52 and high enough to prevent the optical fiber 12 wound on the lead winding portion 19 from falling from the drum. Thus, the type sticking hand 64 can be easily approached to the winding reel and the optimum tape-sticking position can be easily set.
The manufacturing equipment of the optical fiber such as a drawing equipment, a coloring equipment and a rewinding equipment means all processes including the process for winding the optical fiber around the winding reel.
The winding reel according to the present invention is composed of ABS resin, polypropylene resin or other engineering plastic and processed by injection molding. Otherwise, the flange and the drum may be separately produced and combined later.
As described above, according to the winding reel of the present invention, the forward end and backward end of the optical fiber are locked on the same plane and the backward end thereof can be locked at the same position irrespective of the length of the optical fiber which has been wound around the drum of the winding reel.
Although the present invention has been fully described in connection with the preferred embodiments thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications are apparent to those skilled in the art. Such changes and modifications are to be understood as included within the scope of the present invention as defined by the appended claims unless they depart therefrom.
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A winding reel for optical fiber is provided with a drum and a flange. The flange is provided with first and second slits therein for receiving leading and trailing (frontward and rearward) portions of the optical fiber. The length of the slit that receives the forward end of the optical fiber extends from the outer periphery of the flange to the surface of the drum. The slit for receiving the rearward end of the optical fiber is shorter than the forward end receiving slit. The rearward end receiving slit extends from the outer periphery of the flange inwardly a distance such that the slit does not reach a position at which a maximum amount of optical fiber wound on the winding reel is located.
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FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not applicable.
REFERENCE TO SEQUENCE LISTING, A TABLE, OR A COMPUTER LISTING APPENDIX
Not applicable.
COPYRIGHT NOTICE
A portion of the disclosure of this patent document contains material that is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or patent disclosure as it appears in the Patent and Trademark Office, patent file or records, but otherwise reserves all copyright rights whatsoever.
FIELD OF THE INVENTION
The present invention relates generally to vacuum process control. More particularly, the invention relates to a device that utilizes vacuum chambers in conjunction with a pendulum valve that uses a male wedge rotating on a fixed shaft into a fixed female wedge to perform the vacuum sealing function.
BACKGROUND OF THE INVENTION
Within vacuum process control industries there is a growing demand for smaller, more inexpensive and more reliable valves to isolate certain components in a system and to enable these components to operate under vacuum conditions. There are a number of different types of valves currently known for isolating components in a system. For example, without limitation, rectangular gate valves are the most common in the industry. FIG. 1 illustrates an exemplary rectangular gate valve 100 , in accordance with the prior art. A gate 101 of rectangular gate valve 100 moves in a straight line in order to seal rectangular gate valve 100 . The movement of gate 101 in the present example is indicated by an arrow 102 . Rectangular gate valves typically require an air cylinder to actuate the valve, adding the length of the air cylinder to the overall length of the valve. For example, without limitation, referring to FIG. 1 , an air cylinder 103 of gate valve 100 practically doubles the length of rectangular gate valve 100 .
Pendulum valves are also currently used in vacuum process control industries. A pendulum valve offers a smaller overall footprint than a rectangular gate valve, making pendulum valves desirable in systems where space is an issue. Rather than sliding in a straight line, the gate of a pendulum valve rotates on a shaft, driven by a set of links that rotate a drive arm and thus the gate of the valve into an opening. The air cylinder required to rotate a pendulum valve can be mounted on the valve body, thus saving space. Pendulum valves currently being used in the vacuum process controls industry typically use a gate that moves parallel to the valve body, and uses a complex series of links and wheels to lock and seal the valve in a closed position. While currently known pendulum valves rotate on shafts to seal the valve closed, there are no wedges or angled surfaces to facilitate the sealing of the valves. Thus, pendulum valves use basically the same mechanism to close and seal the valve as standard rectangular gate valves, for example, without limitation, gate valve 100 , shown by way of example in FIG. 9 .
In view of the foregoing, there is a need for improved techniques for providing small, reliable and inexpensive valves for use in vacuum pressure systems that uses simple means for creating a vacuum tight seal.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention is illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings and in which like reference numerals refer to similar elements and in which:
FIG. 1 illustrates an exemplary rectangular gate valve, in accordance with the prior art;
FIGS. 2 , 3 , 4 , 5 , and 6 illustrate an exemplary dual wedge valve, in accordance with an embodiment of the present invention. FIG. 2 is a side view of the valve in a closed position, where body covers of the valve have been removed to show the inside of the valve. FIG. 3 is a top view of the valve in the closed position. FIG. 4 is a top, transparent view of the valve in an open position. FIG. 5 is an exploded view of the entire assembly of the valve, and FIG. 6 is a cutaway view of the dual wedge design of the valve with the valve in the closed position;
FIG. 7 shows exemplary components of a dual wedge valve, in accordance with an embodiment of the present invention; and
FIGS. 8 , 9 and 10 illustrate an exemplary single wedge gate valve, in accordance with an embodiment of the present invention. FIG. 8 is a side view of the single wedge gate valve in a closed position without body sides for clarity. FIG. 9 is a cross-sectional view of the single wedge gate valve in the closed position, and FIG. 10 is a section view of the single wedge gate valve.
Unless otherwise indicated illustrations in the figures are not necessarily drawn to scale.
SUMMARY OF THE INVENTION
To achieve the forgoing and other objects and in accordance with the purpose of the invention, a vacuum sealing system and device is presented.
In one embodiment, an apparatus for a gate valve between chambers is presented. The apparatus includes a valve housing defining a flow path between the chambers. A male valve portion is rotatable on a fixed axis in the housing. The male valve portion including at least a first male mating surface positioned at a first angle less than perpendicular to the axis. A female valve portion is fixed in the valve housing for receiving the male portion. The female valve portion including at least a first female mating surface positioned at a second angle matching the first angle. An o-ring seals the male valve portion to the female valve portion when the male valve portion is rotated into the female valve portion from a fully open position to a fully closed position. A polished surface contacts the o-ring when the male valve portion is rotated. Means for providing a sliding action between the male valve portion and the female valve portion when the male valve portion is rotated into the female valve portion. The means for providing a sliding action compressing the o-ring in the fully closed position thereby sealing the gate valve and closing the flow path. Means for rotating the male valve portion between the fully open position and the fully closed position. Another embodiment further includes means for linking the means for rotating and the male valve portion where the linking means maintains the male valve portion in the fully closed position when the means for rotating is inoperative. In other embodiments the chambers are vacuum pressure chambers and the o-ring provides a vacuum tight seal and the male valve portion is rotatable when pressures in the chambers are differentiated. In yet another embodiment the means for rotating is continuously operable for throttling between the fully open position and the fully closed position. In other embodiments the male valve portion further includes a second male mating surface positioned at a third angle less than perpendicular to the axis, the female valve portion further includes a second female mating portion positioned at a fourth angle matching the third angle, the o-ring is on the first male mating surface, the polished surface in on the first female mating surface and the sliding action means provides the sliding action between the second male mating surface and the second female mating surface. In yet other embodiments, the male valve portion further includes a second male mating surface substantially perpendicular to the axis, the female valve portion further includes a second female mating portion substantially perpendicular to the axis, the o-ring is on the first female mating surface, the polished surface in on the first male mating surface and the sliding action means provides the sliding action between the second male mating surface and the second female mating surface.
In another embodiment an apparatus for a gate valve between chambers is presented. The apparatus includes a valve housing defining a flow path between the chambers. A male valve portion is rotatable on a fixed axis in the housing. The male valve portion includes a first male mating surface positioned at a first angle less than perpendicular to the axis and a second male mating surface positioned at a second angle less than perpendicular to the axis. A female valve portion is fixed in the valve housing for receiving the male portion. The female valve portion including a first female mating surface positioned at a third angle matching the first angle and a second female mating surface positioned at a fourth angle matching the second angle. An o-ring is positioned on the first male matting portion for sealing the male valve portion to the female valve portion when the male valve portion is rotated into the female valve portion from a fully open position to a fully closed position. A polished surface on the first female portion contacts the o-ring when the male valve portion is rotated. A slider is between the second male valve portion and the second female valve portion where when the male valve portion is rotated into the female valve portion, the slider provides a sliding action and compresses the o-ring in the fully closed position thereby sealing the gate valve and closing the flow path. An actuator rotates the male valve portion between the fully open position and the fully closed position. Other embodiments further include a linkage between the actuator and the male valve portion where the linkage maintains the male valve portion in the fully closed position when the actuator looses power and the linkage includes a three-part linkage. In another embodiment the male and female mating portions further include generally circular shapes. In still other embodiments the o-ring is positioned in an o-ring groove and the slider includes a Kynar rod in an o-ring groove on the second male mating surface. In yet other embodiments the chambers are vacuum pressure chambers and the o-ring provides a vacuum tight seal and the male valve portion is rotatable when pressures in the chambers are differentiated. In yet another embodiment the actuator is continuously operable for throttling between the fully open position and the fully closed position.
In another embodiment an apparatus for a gate valve between chambers is presented. The apparatus includes means for housing the gate valve defining a flow path between the chambers, means for closing the flow path, means for receiving the means for closing, means for sealing the means for closing and the means for receiving, means for contacting the means for sealing in a low friction manner, means for providing a sliding action between the means for closing and the means for receiving and means for rotating the means for closing between a fully open position and a fully closed position. Yet another embodiment further includes means for linking the means for rotating and the means for closing.
Other features, advantages, and object of the present invention will become more apparent and be more readily understood from the following detailed description, which should be read in conjunction with the accompanying drawings.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention is best understood by reference to the detailed figures and description set forth herein.
Embodiments of the invention are discussed below with reference to the Figures. However, those skilled in the art will readily appreciate that the detailed description given herein with respect to these figures is for explanatory purposes as the invention extends beyond these limited embodiments. For example, it should be appreciated that those skilled in the art will, in light of the teachings of the present invention, recognize a multiplicity of alternate and suitable approaches, depending upon the needs of the particular application, to implement the functionality of any given detail described herein, beyond the particular implementation choices in the following embodiments described and shown. That is, there are numerous modifications and variations of the invention that are too numerous to be listed but that all fit within the scope of the invention. Also, singular words should be read as plural and vice versa and masculine as feminine and vice versa, where appropriate, and alternative embodiments do not necessarily imply that the two are mutually exclusive.
The present invention will now be described in detail with reference to embodiments thereof as illustrated in the accompanying drawings.
Preferred embodiments of the present invention provide a cost-effective, reliable and efficient valve, with few moving parts, that is installed in a vacuum pressure system. In a preferred embodiment, a male wedge arm with a sealing o-ring mounted on the male wedge arm, swinging on a fixed axis into a fixed female wedge, closes the valve and creates a vacuum tight seal. The use of a wedge design eliminates the need for a number of ball bearings, bellows and other parts that are currently used in standard gate valves, such as, but not limited to, links, pins, welded gate frames, wheels, etc. Preferred embodiments may be implemented as dual wedge valves or single wedge valves. A valve according to preferred embodiments is unique in that it uses a pendulum style motion, along with a wedge style arm and valve seat to seal the valve. It is contemplated that fewer parts per assembly in preferred embodiments will result in a more cost-effective and reliable valve. Preferred embodiments generally do not require adjusting, although adjusting is provided with some embodiments. Furthermore, preferred embodiments have the ability to open under differentiated pressure because a sliding action rather than a lifting action is used to open the valve.
FIGS. 2 , 3 , 4 , 5 , and 6 illustrate an exemplary dual wedge valve 200 , in accordance with an embodiment of the present invention. FIG. 2 is a side view of valve 200 in a closed position, where body covers 201 of valve 200 have been removed to show the inside of valve 200 . FIG. 3 is a top view of valve 200 in the closed position. FIG. 4 is a top, transparent view of valve 200 in an open position. FIG. 5 is an exploded view of the entire assembly of valve 200 , and FIG. 6 is a cutaway view of the dual wedge design of valve 200 with valve 200 in the closed position. In the present embodiment valve 200 is sealed vacuum tight when in the closed position. Valve 200 comprises a male wedge arm 203 at a set angle that rotates on a fixed shaft 205 into a fixed female wedge 207 at a set angle.
Referring to FIG. 2 , male wedge arm 203 is shown in the closed position. Both sides of male wedge arm 203 are angled at 7.5 degrees, and male wedge arm 203 swings into fixed female wedge 207 also with 7.5-degree angles on each side. Alternate embodiments may comprise wedges with various different angles. Furthermore, in some embodiments the angle of the top surface of the wedge may be different from the angle of the bottom surface of the wedge as long as the angles of the male and female wedges match to create a vacuum tight seal.
Referring to FIGS. 2 and 5 , shaft 205 on which male wedge arm 203 rotates is captured within the body of valve 200 using O-rings to seal shaft 205 where it protrudes from the body of valve 200 . Male wedge arm 203 is mounted on shaft 205 , being held in position by threaded nuts 209 and washers 211 , thus enabling male wedge 203 to be adjustable in the Z position by moving threaded nuts 209 , washers 211 and male wedge arm 203 up or down shaft 205 . Once male wedge arm 203 is properly located on shaft 205 to fit within female wedge 207 , threaded nuts 209 and washers 211 restrain movement of male wedge arm 203 along shaft 205 , thus holding male wedge arm 203 in place. A key 213 is used to prevent male wedge arm 203 from rotating on shaft 205 , along with a bolt that clamps male wedge arm 203 around shaft 205 . Alternate embodiments may not enable the male wedge arm to be adjusted. In the present embodiment, the upper portion of shaft 205 is locked to an air cylinder 215 to push a drive arm 217 without fear of rotating on shaft 205 .
Referring to FIGS. 2 and 6 , an o-ring 219 on male wedge arm 203 comes into contact with an ultra polished surface 221 of female wedge 207 just prior to male wedge arm 203 wedging into fixed female wedge 207 . In alternate embodiments, the o-ring may be attached to the female wedge and the male wedge arm may have an ultra polished surface. In the present embodiment, o-ring 219 briefly slides on polished surface 221 on the bottom side of female wedge 207 when valve 200 closes to perform the sealing action. Polished surface 221 of female wedge 207 has an ultra smooth surface finish in the area where o-ring 219 contacts, for example, without limitation, a 16-finish surface, a non-stick coating, etc. Polished surface 221 aids in preventing damage and wear to o-ring 219 . On the side of male wedge arm 203 opposite o-ring 219 , a Kynar rod 223 is placed in an o-ring groove and is used to provide the sliding action required when male wedge arm 203 comes into contact with the opening of fixed female wedge 207 . Those skilled in the art, in light of the present teachings, will readily recognize that a multiplicity of suitable means may be used to provide the sliding action between the male wedge and the female wedge such as, but not limited to, other types of smooth, non-wear materials, ball bearings, air bearings, etc. Furthermore, in alternate embodiments the means for providing the sliding action may be incorporated into the female wedge rather than the male wedge arm. In the present embodiment as male wedge arm 203 is driven into female wedge 207 , male wedge arm 203 pushes against polished surface 221 of female wedge 207 and Kynar rod 223 pushes against the opposite surface of female wedge 207 . This action compresses o-ring 219 against polished surface 221 to form a vacuum tight seal.
Referring to FIGS. 3 and 4 , the drive system comprises drive arm 217 mounted on shaft 205 , attached to a fixed length link of a three-part linkage 225 , which in turn is attached to another link of three-part linkage 225 , which is attached at the other end to a fixed linkage mount 227 with a shoulder bolt 229 . Air cylinder 215 actuates valve 200 by driving a three-part linkage 225 , which actuates drive arm 217 , which rotates male wedge arm 203 by rotating shaft 205 . Alternate embodiments may be implemented without a three-part linkage. In these embodiments the air cylinder is connected directly to the drive arm, and the end of the drive arm not connected to the air cylinder is connected to the shaft. In the present embodiment, air cylinder 215 is a 1.5″ bore pneumatic air cylinder; however, alternate embodiments may comprise air cylinders of various sizes depending on factors such as, but not limited to, the size of the valve or the application of the valve. Other alternate embodiments may use different means for actuating the valve such as, but not limited to, hydraulic cylinders, electric motors, manual levers, etc. In the present embodiment, air cylinder 215 comprises two magnetic reed switches on each end of the air cylinder stroke to indicate the open and closed positions. Air cylinder 215 is pivotally mounted to valve 200 with a mount bracket 231 at a pivot point 233 . Shaft 205 is rotated by air cylinder 215 by pushing three-part linkage 225 and drive arm 217 , which is clamped to shaft 205 . When air cylinder 215 is in an extended position, the valve is in the open position, and as the shaft of air cylinder 209 retracts, drive arm 217 rotates, thus rotating male wedge arm 203 into female wedge 207 . Referring to FIG. 4 , air cylinder 215 is shown fully extended, which fully extends three-part linkage 225 so that drive arm 217 is in line with the adjacent link of three-part linkage 225 and opens valve 200 , and referring to FIG. 3 , air cylinder 215 is shown in the fully retracted position, which fully retracts three-part linkage 225 so that drive arm 217 is at a 90-degree angle to the adjacent link of three-part linkage 225 and closes valve 200 . In alternate embodiments, the drive system may be configured differently so that the links of the three-part linkage and the drive arm create various different angles in the open and closed positions. In the present embodiment, three-part linkage 225 enables valve 200 to remain sealed, or locked over, in the event of a power failure. The lock over refers to the angle of drive arm 217 and linkage 225 being at an angle at least 1 degree greater than 90 degrees. If a force is applied externally to the male wedge 203 to attempt to open the valve, the angle prevents the male wedge 203 from moving or backing out, and only when the air cylinder 215 is activated can the valve open.
Referring to FIGS. 3 and 4 , a typical mounting flange 235 is also shown on body cover 201 . Mounting flange 235 enables valve 200 to be mounted to other components in the system. Those skilled in the art, in light of the present teachings, will readily recognize that a multiplicity of suitable mounting flanges are available for use on valve 200 , for example, without limitation, flanges of different shapes such as, but not limited to, squares or rectangles.
FIG. 7 shows exemplary components of a dual wedge valve, in accordance with an embodiment of the present invention. The components shown in FIG. 7 include a male wedge arm 701 , a female wedge 703 within a valve body 705 and a drive shaft 707 on a drive arm 709 . Male wedge arm 701 comprises a top surface and a bottom surface; each sloped at a 7.5-degree angle to create a total angle of 15 degrees within male wedge arm 701 . Female wedge 703 also comprises a top surface and a bottom surface; each sloped at 7.5 degrees to match the angle of male wedge arm 701 . In alternate embodiments, the surfaces of the male wedge arm and the female wedge may be sloped at angles other than 7.5 degrees. The top and bottom surfaces of male wedge arm 701 each have an o-ring groove 711 . An o-ring may be inserted into one o-ring groove 711 to create a vacuum tight seal when the valve is closed, and a smooth, non-wear material, such as, but not limited to, Kynar, or other sliding means such as, but not limited to, ball bearings, may be inserted into the other o-ring groove 711 to facilitate the sliding of male wedge arm 701 along female wedge 703 . The o-ring of male wedge arm 701 slides on and creates a seal with an ultra smooth, polished surface 713 of female wedge 703 . When in an assembled valve, male wedge arm 701 is attached to drive shaft 707 . When drive shaft 707 is actuated by drive arm 709 , male wedge arm 701 rotates into or out of female wedge 703 .
FIGS. 8 , 9 and 10 illustrate an exemplary single wedge gate valve 800 , in accordance with an embodiment of the present invention. FIG. 8 is a side view of single wedge gate valve 800 in a closed position without body sides for clarity. FIG. 9 is a cross-sectional view of single wedge gate valve 800 in the closed position, and FIG. 10 is a section view of single wedge gate valve 800 . In the present embodiment, valve 800 comprises a rotating wedge 801 and a fixed wedge 803 . Rotating wedge 801 is a smooth faced plate that swings on a wedge arm 802 on a fixed shaft 804 toward fixed wedge 803 with a captive o-ring 805 . In the present embodiment, o-ring 805 is set into fixed wedge 803 , and rotating wedge 801 has an ultra smooth surface, for example, without limitation, a 16-finish or a non-stick coating, in the area where rotating wedge 801 comes into contact with o-ring 805 . In alternate embodiments the o-ring may be set into the rotating wedge, and the fixed wedge may have an ultra smooth finish. In the present embodiment, wedge arm 802 swings on a fixed horizontal plane. Two wheels 807 roll on an upper plate 809 creating additional pressure on rotating wedge 801 to force rotating wedge 801 against o-ring 805 in fixed wedge 803 . Those skilled in the art, in light of the present teachings, will readily recognize that a multiplicity of suitable means may be used to create additional pressure on the rotating wedge in alternate embodiments, such as, but not limited to, rollers, ball bearings, etc. In the present embodiment, rotating wedge 801 and fixed wedge 803 each have a 7.5-degree surface; however, alternate embodiments may comprise wedges with various different angles. Referring to FIG. 10 , the surfaces of rotating wedge 801 and fixed wedge 803 are non-parallel when in an open position, and these surfaces become parallel as rotating wedge 801 comes into contact with o-ring 805 , mounted on fixed wedge 803 .
Similarly to the embodiment shown by way of example in FIGS. 2 through 6 , to actuate rotating wedge 801 , an air cylinder 811 drives a drive arm 813 , which rotates shaft 804 . Wedge arm 802 , which is attached to rotating wedge 801 , is locked to shaft 804 and rotates when shaft 804 is rotated by drive arm 813 . Some embodiments may comprise a three-part linkage in the drive system, and other embodiments may not comprise a three-part linkage. Furthermore, those skilled in the art, in light of the present teachings, will readily recognize that the rotating wedge may be actuated by various different means other than an air cylinder in alternate embodiments such as, but not limited to, a hydraulic cylinder, an electric motor, a manual lever, etc. In the present embodiment, rotating wedge 801 and fixed wedge 803 generally do not require adjusting. However, adjusting may be performed by sliding wedge arm 802 up or down shaft 804 and using threaded nuts and/or a key to hold wedge arm 802 in place. Alternate embodiments may be implemented that are not adjustable. Referring to FIGS. 8 , 9 and 10 , single wedge embodiments have benefits over existing valves including, without limitation, a high cycle life because of the lack of bellows, the ability to water cool with no lines, ease of repair and maintenance, and suitability for throttling from completely closed to fully open.
Those skilled in the art, in light of the present teachings, will readily recognize that embodiments of the present invention may be used in various different applications. The foregoing description was directed to embodiments for use in vacuum process control systems; however, embodiments of the present invention may be used in other types of systems including, without limitation, fluid control systems, systems to control the flow of a gas, etc. Furthermore, some of these applications may not require a vacuum tight seal. Embodiments of the present invention for use in applications not requiring a vacuum tight seal may be implemented without sealing components such as, but not limited to, the o-ring or the ultra smooth surface on the wedge.
Having fully described at least one embodiment of the present invention, other equivalent or alternative methods of providing a pendulum valve incorporating wedges according to the present invention will be apparent to those skilled in the art. The invention has been described above by way of illustration, and the specific embodiments disclosed are not intended to limit the invention to the particular forms disclosed. For example, the particular implementation of the male wedge may vary depending upon the particular type of female wedge used. The male wedges described in the foregoing were directed to implementations with flat surfaces; however, similar techniques are to use wedges with curved surfaces. Curved implementations of the present invention are contemplated as within the scope of the present invention. The invention is thus to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the following claims.
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An apparatus for a gate valve between chambers includes a valve housing defining a flow path. A male valve portion is rotatable on a fixed axis in the housing. The male valve portion including a first male mating surface positioned at a first angle less than perpendicular to the axis. A female valve portion is fixed in the valve housing for receiving the male portion. The female valve portion including a first female mating surface positioned at a second angle matching the first angle. An o-ring seals the male valve portion to the female valve portion when the male valve portion is rotated into the female valve portion. A polished surface contacts the o-ring when the male valve portion is rotated. When the male valve portion is rotated into the female valve portion the o-ring is compressed thereby sealing the gate valve and closing the flow path.
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FIELD OF THE INVENTION
The present invention relates to physical security systems, and more particularly relates to controlled-access enclosures for locks, latches, switches, outlets, valves, and the like.
BACKGROUND AND SUMMARY OF THE INVENTION
For expository convenience, the present invention is described with reference to an illustrative application thereof, namely the provision of a locked cover for mechanical locks. However, it should be recognized that the invention is not so limited. Instead, it finds application wherever access to a fixture, such as an electrical or phone outlet, a hose bib, a switch, a valve or the like, should be restricted.
Companies with mechanically-keyed doors constantly face the dilemma of whether to re-key a door or facility when a "key carrying" employee quits or is terminated. A similar issue arises when an employee loses a key. While electronic access control systems provide technical solutions to these problems, cost and installation issues associated with their implementation limit their use.
PCT publication WO 94/12749 to Hungerford shows a hybrid system in which a key to a mechanical door lock is held in a battery powered strong box adjacent the door. The strong box has a keyboard on its face. If a user correctly enters a code number on the keyboard, the strong box opens and the user can use the key contained therein to open the locked door.
While advantageous in some respects, the Hungerford system is disadvantageous in others. For example, the problem of key security still persists. If a user duplicates the key while it is out of the strong box, the element of electronic protection provided by the system is essentially defeated. The mechanical lock must be re-keyed to make the system secure again.
Further, the provision of a keypad on the outside of Hungerford's strong box invites vandalism. Keyboards are also notoriously difficult to waterproof, making the internal lock electronics susceptible to water damage. Still further, there is the recurring problem of battery failure, which can render the strong box permanently locked (or freely openable, if designed to fail in that mode). Moreover, the Hungerford system does nothing to enhance the security of the keyed lock itself; the keyed lock is still accessible to attack using conventional locksmithing tools.
In a known variant of the Hungerford system, an existing mortise lock is removed from a door and replaced with a simple flip bolt latch. A security lid is then mounted over the flip bolt. A user can only gain access to the flip bolt by entering a code on a keypad on the lid. If the code is entered properly, the lid can be opened, and the user can turn the flip bolt.
While this latter system rectifies certain of Hungerford's drawbacks, it introduces others. One is the need to remove an existing mortise lock and replace it with the flip bolt. Another, relating to physical security, is the substitution of a simple flip lock for what may have been a more robust mortise lock. Other problems of the original Hungerford system persis, including vandalism, battery failure, etc.
In accordance with a preferred embodiment of the present invention, the foregoing and other drawbacks of the prior art are overcome. An electronic security enclosure conceals a keyed lock (or other mechanical access device, such as a door knob, latch, release knob, etc.) behind a movable member. When the security enclosure is unlocked by an electronic key, and the movable member is moved to reveal the keyed lock, the key is captured, preventing its removal until the enclosure is again secured over the keyed lock. A variety of operational features, including provision for keyholder access restrictions, time-of-day restrictions, provision of different classes of keys for employees and vendors, etc., are also provided.
The foregoing and additional features and advantages of the present invention will be more readily apparent from the following detailed description, which proceeds with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a view of a security enclosure according to one embodiment of the present invention.
FIG. 2 is another view of the enclosure of FIG. 1 showing its placement over an existing deadbolt/mortise lock.
FIG. 3 shows how the security enclosure of FIG. 1 is adapted to receive an electronic key.
FIGS. 4-6 shows how opening of the security enclosure of FIG. 1 reveals the keyed lock concealed therein, and also acts to trap the key, preventing its removal.
FIGS. 7A and 7B are electrical block diagrams of the security enclosure and key control circuits, respectively.
DETAILED DESCRIPTION
To provide an comprehensive disclosure without unduly lengthening this specification, applicant incorporates by reference U.S. Pat. Nos. 5,280,518, 5,090,222, 5,046,084, 4,967,305, 4,864,115, 4,851,652, 4,800,255, 4,777,556, 4,594,637, and copending applications Ser. Nos. 07/790,642, 07/819,345, 08/099,743, and 08/119,967, each of which is owned by the present assignee and details structures, circuitry, operational features, etc., that can be advantageously employed in a security enclosure according to the present invention.
The present invention is illustrated with reference to an illustrative application thereof, namely securing a keyed lock. It will be recognized, however, that the invention can likewise be used with a great variety of other mechanical access devices (deadbolts, mortise locks, flip locks, latches, doorknobs, padlocks, release knobs, etc.,).
Referring to FIGS. 1-6, the illustrated security enclosure 10 is formed of durable metal or high impact plastic, and is secured over a keyed door lock 12 on a door or door frame 14. The enclosure includes a base plate 16, a slidable member 18, and a nest 20 for receiving an electronic key 22 (FIG. 3).
The base plate 16 defines an opening 24 through which the keyed door lock 12 can be accessed. The edges 25 of the base plate define tracks in which the slidable member is engaged. The nest 20 is defined, in part, by a lip 26 that extends downwardly from beneath the slidable member 18 and forms a channel into which the key can be positioned.
The key 22 is a known device, and may be of the sort illustrated in the foregoing patent references. To open the security enclosure, the key 22 is slid into the nest 20, with the bottom of the key resting on a footer 28, until the key abuts a stop member 30. The keypad 32 thereon is then operated to, e.g., enter a personal identification number (PIN), and request opening of the slidable member 18 (e.g. by pressing the Obtain Key button 32a).
If keypad 32 is operated in the correct sequence, signals are sent to control electronics 34 (FIG. 7) in the security enclosure 10 (which can be, e.g., of the form detailed in the cited patent references). The control electronics, in turn, send an actuating signal to a solenoid-controlled latch 36, which releases the slidable member 18 from its illustrated, latched position. The user then slides the slidable member downwardly to reveal the keyed lock 12. In so doing, the user's key 22 is trapped behind the slidable member.
Once the keyed lock 12 is exposed, the user operates same with a mechanical key. In the illustrated embodiment, the user carries the mechanical key with him, but in other embodiments, the mechanical key can be disposed behind the slidable enclosure on a durable tether, thereby available to anyone authorized to open the security enclosure 10. (It will be recognized that mechanical keys to the door lock 12 can be distributed widely, since they are useless to persons without authorization to operate the electronic security enclosure.)
After the user has operated the keyed lock, the slidable member 18 must be returned to its original, latched, position before the user's key can be removed from its entrapped position in the nest 20.
In the illustrated embodiment, the control circuitry 34 and associated solenoid-controlled latch 36 do not rely on an internal battery for their operating power. Instead, they receive operating power from the key 22, by an arrangement such as is taught by the cited patent references.
The fastening of the security enclosure 10 on door 14 is accomplished by threaded fasteners which cannot be accessed without first sliding the slidable member 18 to the lower position. In some embodiments, a mounting bracket is first mounted to the door 14, and the security enclosure is then mounted thereto.
In some door installations (e.g. with glass doors), the lock may be mounted in a relatively thin frame member, such as member 37 in FIGS. 5-6. The preferred embodiment is desirably designed to mount on members as narrow as two inches across.
(If desired, a magnetic alarm contact can be provided at sites that want to trigger a master alarm if the security enclosure is removed from the door 14 in a criminal attack. The control circuitry within each security enclosure may be programmed to interface with common alarm system protocols, enabling the system to be de-activated or activated by the authorized release of the security enclosure.)
Referring to FIGS. 7A and 7B, the security enclosure and key each includes a microprocessor (CPU) 38 with associated ROM (EEPROM) memory 40 and RAM memory 42. Each further includes an interface 44 for interacting with the other. To enable powering of the security enclosure 10 from the key 22, the interface 44 desirably provides electrical connection between the key and security enclosure interfaces 44, but in other embodiments energy can be transferred by coupled coils. In embodiments where power needn't be provided to the security enclosure, other interface techniques, such as infrared, can be utilized.
The key 22 additionally includes a battery 46, a beeper 48 (which is desirably a piezo-electric transducer), an LCD display 50, a clock, and a permanently programmed ID code, all as described in the cited patent references. (The clock may be implemented using the CPU, rather than as dedicated circuitry.)
The security enclosure 10 can include a small battery if desired, e.g. to maintain the RAM memory 42a in a keep-alive state, or to power a light on the face of the lid. (This light can be programmed to flash during certain hours of the day, simulating an alarmed condition.) But the power to operate the solenoid latch 36 is, as noted above, derived from the key 22.
The provision of a microprocessor and memory in both the security enclosure and the key allows for a host of operational features, some of which are reviewed below, and others of which are detailed in the cited patent references.
The illustrated system contemplates use of keys belonging to a variety of different classes, each with different restrictions. (The keys themselves are identical, but are programmed to effect different capabilities.)
The most capable key is the owner/manager key. In addition to opening the security enclosure, this key is used to program the security enclosure control circuitry 34, and to read the access log information which has been recorded therein.
In the depicted embodiment, there is only one owner/manager key for each security enclosure. This correspondence is effected by assigning each security enclosure with a unique initialization code, and using this code to initialize a corresponding owner/manager key.
In particular, the process for initializing a key for a specific security enclosure is as follows. First, from the menu prompts on the display 50, the user selects the option "Initialize Security Enclosure,"followed by the user's PIN code. Next, the user selects the option "Master" from the menu prompts, and follows this with a user-selected master code. After the user enters this code, the key is slid into the nest 20. (As detailed in the cited patent references, the preferred key allows most keyboard entries to be made before the key is mated with the lock device--in this instance the security enclosure.) The control circuits in the key and security enclosures then communicate and effect initialization so the enclosure thereafter recognizes that key, alone, as its owner/manager key.
During the foregoing process, the owner/manager key creates a "scrambled" initialization code that is generated from the serial number of the key and a user-selected master code. This is the initialization code that is written into the memory of the security enclosure, together with the serial number of the owner/manager key.
If the owner/manager key is thereafter lost or stolen, each of the security enclosures that it "owned" must be re-initialized. This process requires knowledge of the scrambled initialization code. This code is obtained from the system database, where it is reconstructed by knowledge of the lost key's serial number and PIN code, and the user-selected master code. Once this initialization code is obtained, the security enclosure can be re-initialized from a new owner/manager key by the following procedure. From the key menu, the "Re-initialize" option is selected, followed by a valid PIN code. The display next prompts for the previous scrambled initialization code. After this code is entered, the key is inserted into the nest 20 and the key and security enclosure communicate to complete the reinitialization process.
The security enclosure creates a new scrambled initialization code, and writes it and the serial number of the new owner/manager key into its memory. The old owner/manager serial number is erased. This disqualifies the original owner/master key from further use.
If any of the codes necessary for reinitialization is forgotten, there is an option for a "grand master" key to be used to erase all programming in the security enclosure. After erasing this programming, the "Initialize" process is selected and a new owner/manager key is assigned to the security enclosure.
The other functions performed with the owner/manager key are programming of security enclosures, and reading their access logs. Consider the illustrative application of a security enclosure used to control access to a locked doors at a franchise restaurant. The restaurant manager would use the owner/manager key to program each security enclosure within the facility. This programming would allow authorized employee keys (another class of keys) to open the security enclosures. This is accomplished by programming the serial number of each authorized employee key into the memory of the security enclosures. This process typically takes less than 30 seconds.
To lock out an employee key, the restaurant manager simply reverses the process and removes the serial number of the employee key from the memory of the security enclosures. This feature allows the restaurant manager to instantaneously prevent an employee from gaining access to a mechanical lock.
In a like manner, the restaurant manager can effect other programming options, including restricting access by day, time of day, etc.
The step-wise procedure for these programming operations follows the general model of the initialization procedure detailed above, but the different functions are selected from the menu prompts on the display.
The other function available to owner/manager keys is to recover access log information from a security enclosure. To perform this operation, the restaurant manager inserts the owner/manager key into the nest 20 and selects the "Read" option from the menu prompts. The access log data stored in the security enclosure's memory is then written to the key memory.
From the key memory, the data can be handled in various ways. The simplest utilizes the display on the key to present abbreviated access data (e.g. date, time, serial number of accessing key) for viewing by the manager. A button on the keypad is used to scroll from one entry to the next.
More comprehensive review of the access data can be provided in one of two manners. For small installations (those without a central administrative computer), the restaurant manager telephones a service provider, such as the assignee. A synthesized voice at the service provider's facility instructs the manager to position the key transducer 48 next to the phone mouthpiece, and operate the keyboard to initiate an audible downloading of the data from the key over the telephone. (Again, this process is further detailed in the cited patent references.) The service provider's computer then provides a voiced recitation to the manager of the downloaded access data. The manager can choose, by Touch-Tone instructions, to have the service provider send the downloaded data in FAXed form to a telephone number entered by the manager during the phone call. If the service provider has not earlier been provided with data correlating key serial numbers to the keys' respective custodians, the voiced or FAXed access log data will include serial numbers rather than names.
Companies with large numbers of security enclosures may choose a second option, namely to install their own central computer and support facilities. Such a system allows enterprise-wide tracking of access data in a master database, and enables interpreted reports (e.g. names instead of numbers), and reports specialized for different security tracking applications (e.g. reports detailing accesses for each employee, reports detailing accesses to particular security enclosures, etc., etc.).
The second class of key, as alluded to earlier, is the employee key. This is the key assigned to individuals who are employees of the organization utilizing the security enclosures. For example, in the restaurant example cited above, shift managers who currently carry mechanical keys would be assigned electronic employee keys.
To open the security enclosure, the employee simply inserts the key into the next, and depresses the "Open" button. (Entry of a PIN code is optional for employee keys.) If a security enclosure has not been programmed to accept a particular employee key, the enclosure will not open.
The third class of key is the vendor key. Many organizations have been forced to issue mechanical keys to delivery companies and service companies for after hours access. This creates a number of problems, not the least of which is auditing the vendors' use of these keys. Any change in vendor status requires rekeying of the locks.
Vendor keys according to the preferred embodiment of the present invention overcome these problems. Such keys are programmed to expire (become inactive) at a preset interval (e.g. daily, weekly, etc.). Such keys also automatically compile a log detailing each security enclosure access they've made (by enclosure ID, date and time.) To reactivate an expired key, the user must obtain an update code from the central computer and input that code into their key. During the process of obtaining this code, the central computer requires the keyholder to download all of its logged activity. This audit trail allows a manager to see the daily, weekly, or monthly activity of each vendor and each vendor keyholder.
The provision of update codes to vendors is desirably automated. Each vendor, if classified in the central computer database as "active," can obtain a key update code, via Touch-Tone, 24 hours per day, 7 days per week.
The expiration feature eliminates the need for the facility manager to program each security enclosure with all of the potential serial numbers of the vendors who have been granted access to the facility. The need for the facility manager to perform a lockout function if a vendor key is stolen is also greatly diminished.
The preferred vendor key also requires a vendor access code (in addition to the user's PIN) to open a security enclosure. Each vendor is assigned a different code. Each person using a vendor key must enter the vendor access code into the key (or have the key preprogrammed with this code) in order to gain access to the enclosure. Each security enclosure must be programmed with the vendor codes that it is to accept.
This feature enables an organization, such as the cited restaurant franchise, to provide or deny access to vendors by reprogramming the security enclosures to accept or reject the vendor access code. This feature provides the end results of a change in mechanical lock, but can be accomplished within minutes and without any expense.
The vendor access code can also be used as a building access code, since it can be specific to one (or more buildings).
Each security enclosure can be programmed for a variety of access control levels. Control levels can be effected on a per-enclosure or per-key basis, or more generally.
Each security enclosure can be programmed to lock out all keyholders by date, during specific hours of the day, or it can be set at a "privacy" level which prevents all keys from opening the enclosure (except the owner/manager key). In this programming mode, all keys are subject to the programming options set in the enclosure. In the preferred embodiment, the enclosures have the capability to store 12 different lockout dates (e.g. holidays), and five daily time-of-day lockouts.
Security enclosures can also be programmed on a per-key basis. For example, an enclosure can be programmed to lock out a specific employee key on specific days, or at specific times of day (e.g. an employee can be limited to access from 8:00 a.m. to 5:00 p.m. on Mondays, Wednesdays, and Fridays, only). Each security enclosure can store such key-specific programming instructions for up to 100 different keys.
Each security enclosure can also be programmed with up to 20 different vendor access codes, and have different day of week, and time of day restrictions for each.
If desired, embodiments according to the present invention can advantageously employ radio-reprogramming and radio-preauthorization, as detailed in the cited patent references.
From the foregoing, it will be recognized that the illustrated embodiment of the present invention finally solves the longstanding problem of mechanical re-keying, and does so without the cost or difficulty of replacing existing locks with electronic counterparts. Further, the illustrated embodiment can be installed without any wiring, and does not suffer from the battery failure problems of prior "solutions."
In accordance with another aspect of the present invention, a family of different access control devices is provided, each of which is operable with a common key. One such access control device can be a security enclosure of the sort described above. Another can be a strong box mounted to a building and having a key contained therein. Yet another can be an electronic padlock having a lockable shackle operable with the electronic key. Still another is a mortise door lock having a locking bolt that extends linearly to engage with a recess in a cooperating member (e.g. door frame). Yet another is a cam lock having a locking member that rotates into a locking position to prevent a secured member from moving. Each of these access control devices receives power from the key, and serves to log access data as set forth above.
Having described the principles of my invention with reference to a preferred embodiment and certain variations thereon, it should be apparent that these examples can be modified in arrangement and detail without departing from such principles. For example, while the illustrated embodiment contemplates providing each security enclosure with a list of keys to be accepted, in other systems the enclosure can be provided with a list of keys to be "locked out," and accept all other keys of a given class (e.g. assigned to a given corporate employer). Likewise, the illustrated embodiment can employ various combinations of other features disclosed in the cited patent references. Still further, while the invention has been illustrated with reference to a protective member 18 which slides to reveal the keyed lock within the enclosure, a variety of other mechanical access arrangements, such as hinged doors, can alternatively be employed. Likewise, other mechanical aspects of the illustrated embodiment can be varied in ways familiar to the artisan. Yet further, the principles of the present invention can also be applied to systems like those discussed in the Background section in which an existing mechanical lock is replaced with a simple flip lock, and the security enclosure is used to restrict access thereto.
As noted earlier, the applicability of the invention extends beyond securing locks, and encompasses securing any fixture (generally flush mounted). For example, in settings such as public marinas and campgrounds, there may be power and water hook-ups that are to be used only by paying customers, and are thus candidates for use of the present invention. Likewise, telephone outlets may be provided in generally public places (such as in meeting rooms in hotels), and access thereto should be restricted. Still other applications include switches of various forms and purposes (e.g. for controlling power to life support equipment in hospitals). Yet other applications include valves and connections to various fluid and gas supplies.
In view of the many possible embodiments to which the principles of the invention may be put, it should be recognized that the detailed embodiments are illustrative only and should not be taken as limiting the scope of my invention. Rather, I claim as my invention all such embodiments as may come within the scope and spirit of the following claims and equivalents thereto.
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An electronic security enclosure conceals a device, such as a switch, valve, outlet, or lock, behind a movable member. When the movable member is unlocked, by an electronic key, and moved to reveal the concealed device, the key is captured, preventing its removal until the enclosure is again secured over the device. A variety of operational features, including provision for keyholder access restrictions, time-of-day restrictions, provision of different classes of keys for employees and vendors, etc., are also provided. The invention also contemplates a plurality of access control devices, including lock boxes, padlocks, mortise locks, cam locks, etc., that are each operable by a common electronic key.
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FIELD OF THE INVENTION
The present invention is directed to monolithic structures capable of resisting crack propagation and maintaining structural integrity in the presence of large cracks.
BACKGROUND OF THE INVENTION
Structures, such as those found on aircraft and spacecraft, are often subject to stresses that may cause cracking in such structures. Left unchecked, such cracks can grow to critical length and cause loss of structural integrity. For example, a wing of an aircraft, which is subject to flexing up and down throughout every flight the aircraft makes, may develop cracks typically running in the fore-aft direction perpendicular to the tension load direction. Such cracking may affect structural integrity resulting in a weakening of the wing. Federal and military regulations require that such structures be designed to the point of being “fail-safe” for the maximum loads expected in any flight. As a result, aircraft that might be deemed very safe even with some cracked components might nonetheless be precluded from flight until the cracked components are repaired. The processes of finding small cracks and equipping every airport to fix every possible structural component of every aircraft may be difficult and expensive. Accordingly, it is desirable to create structures that are capable of retarding cracking to minimize any loss of structural integrity until proper maintenance can be performed.
SUMMARY OF THE INVENTION
In a first aspect, a damage-tolerant monolithic structure configured to resist cracking includes a substantially-planar element having a length, width and thickness, and one or more first stiffening elements monolithically integrated into the first planar element and running in a parallel direction, wherein each first stiffening element includes, a first stiffening flange having a generally rail-like structure running along the length of the planar element and one or more first webbings connected to the planar element and extending away from the planar element to the stiffening flange, wherein each webbing of the first webbings includes a row of integral holes running along the length of the webbing, the holes being in a shape designed to hinder the progress of a crack in the monolithic structure.
In a second aspect, a damage-tolerant monolithic structure configured to resist cracking includes a substantially-planar element having a length, width and thickness, and one or more means for stiffening and providing crack retardation monolithically integrated into the first planar element.
In a third aspect, a method for manufacturing a damage-tolerant monolithic structure configured to resist cracking includes welding a substantially-planar element to one or more first stiffening elements, wherein each first stiffening element includes a first stiffening flange having a generally rail-like structure running along the length of the planar element; and one or more first webbings connected to the planar element and extending away from the planar element to the stiffening flange, wherein each webbing of the first webbings includes a row of integral holes running along the length of the webbing, the holes being in a shape designed to hinder the progress of a crack in the monolithic structure.
There has thus been outlined, rather broadly, certain embodiments of the invention in order that the detailed description thereof herein may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional embodiments of the invention that will be described below and which will form the subject matter of the claims appended hereto.
In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of embodiments in addition to those described and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein, as well as the abstract, are for the purpose of description and should not be regarded as limiting.
As such, those skilled in the art will appreciate that the conception upon which this disclosure is based may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 depicts a planar element with a first single-sided stiffening element capable of hindering cracking.
FIG. 2 depicts a planar element with a first two-sided stiffening element capable of hindering cracking.
FIG. 3 depicts a planar element with a second single-sided stiffening element capable of hindering cracking.
FIG. 4 depicts a planar element with a second two-sided stiffening element capable of hindering cracking.
FIG. 5 depicts webbings with a variety of hole types.
FIG. 6 depicts a variety of planar elements with a stiffening support elements.
FIG. 7 depicts the manufacture of several crack-tolerant planar elements.
FIG. 8 is a flowchart outlining an exemplary technique for manufacturing damage-tolerant monolithic structures.
FIG. 9 depicts the manufacture of several crack-tolerant planar elements.
DETAILED DESCRIPTION
Today there is a trend in the aerospace industry to redesign multi-piece structures into monolithic structures to minimize the number of parts. Unfortunately, not all aircraft or spacecraft parts lend themselves to integration without some drawbacks. In particular, a single crack in a monolithic structure can lead to critical damage as the crack grows across the structure. Although a crack in a panel might grow more slowly when confronted with an integral stiffening member, such as an integrated “I-beam”, the stiffening member by itself is generally insufficient to completely retard further cracking. Accordingly, some special accommodations must be made for panels (or other structures) needing both structural support and crack retardation.
FIG. 1 depicts a crack-resistant structure 10 . As shown in FIG. 1 , the crack-resistant structure 10 has a planar element 12 and a stiffening element 13 . The stiffening element 13 consists of a flange 18 and a single webbing 16 connecting the flange 18 to the planar element 12 . As further shown in FIG. 1 , the webbing has a row of elliptical holes 17 .
In operation, the modified stiffening element 13 can act both for structural support and as a damage containment device. That is, should a crack form in and propagate across the planar element 12 into the stiffening element 13 , the crack will tend to propagate up to the edge of one of the holes 17 . Upon reaching a hole 17 , the crack will stop propagating. The shape and placement of each hole 17 can be designed to have a low stress concentration to avoid the development of secondary crack initiation. Thus the flange 18 serves to stiffen the planar element 12 while the webbing 16 (with holes 17 ) serves as a crack-retardation device.
When cracking might otherwise reduce the stiffness of the planar element 12 (or other plate-like structure), the monolithic structure 10 of FIG. 1 can serve to provide structural integrity by redistributing a load between the planar element 12 and the flange 18 . Accordingly, it should be appreciated that the particular dimensions of the flange 18 can be specified in a manner to meet various “fail-safe” load conditions despite any substantial cracking that might reasonably be expected to occur. For example, a structural analysis might indicate that under any expected load, the flange 18 would need to be no larger than one inch by two inches even if the planar element 12 had multiple cracks intersecting the stiffening element 14 . However, in situations where some “padding” to the specification is desired, such as a 50% over-design requirement, a 1.5 inch by two inch flange might be appropriate.
FIG. 2 depicts a second crack-retardant structure 20 having a planar element 22 and two diametrically opposed stiffening elements 24 and 26 . As is evident by FIG. 2 , each of the stiffening elements 24 and 26 are individually similar to the one-sided stiffening element 13 of FIG. 1 and similarly integrated into the planar element 22 .
As further shown in FIG. 2 , the webbing holes 25 for stiffening element 24 are staggered in relation to the webbing holes 27 of stiffening element 26 . Such staggering of the holes can provide a more robust crack retardation as compared to configurations where holes might be aligned.
FIG. 3 shows another structure 30 having crack resistant properties. As shown in FIG. 3 , the structure 30 includes a planar element 32 connected to a flange 38 by two webbings 34 and 36 in such a manner as to form an isosceles trapezoidal cross-section with the planar element 32 . While the particular configuration reflects an isosceles trapezoidal cross-section, it should be appreciated that other forms of trapezoids or quadrilaterals otherwise might be formed with various degrees of effectiveness.
Also shown in FIG. 3 , both webbings 34 and 36 have respective rows of holes 35 and 37 , which in the present embodiment are staggered with respect to one another. As with the structure of FIG. 2 , staggering the holes 35 and 37 can increase the structure's crack resistive nature.
Next, FIG. 4 depicts yet another structure 40 having planar element 42 and two diametrically opposed stiffening elements 44 and 46 . As with the structure of FIG. 2 , the double-sided arrangement of crack-resistant stiffening members 44 and 46 can provide increased performance as compared to one-sided stiffening arrangements. A careful view of FIG. 4 shows that the holes for each diametrically opposed webbing are staggered with respect to one another.
FIG. 5 depicts three separate structures 50 , 52 and 54 having holes of an elliptical, ovoid and circular nature respectively. Although practically any form of hole might be advantageous, holes having no corners or sharp curves can provide increased performance in comparison to holes having sharp corners or sharply rounded corners.
FIG. 6 depicts three separate structures 62 , 64 and 66 having arrays of one-sided and two-sided stiffening elements. As shown in FIG. 6 , structures 62 , 64 and 66 can use combinations of the one-sided and two-sided elements shown in FIGS. 3 and 4 . However, in other embodiments, combinations of the one-sided and two-sided elements shown in FIGS. 1 and 2 can be used. In still other embodiments, any combination of any of the stiffening structures of FIGS. 1-4 can be used, as well as other stiffening structures not shown. Still further, combinations of the monolithic structures can be made with stiffening components not monolithically integrated.
Still further, in addition to using stiffening elements arranged in simple parallel rows, two-dimensional arrangements of stiffening elements can be applied. For example, in a first embodiment, a combination of any of the stiffening elements depicted in FIGS. 1-4 can be arranged in criss-cross patterns to form inter-dispersed squares, rectangles or diamonds. In still other embodiments, three sets of parallel rows of stiffening elements can be arranged to form inter-dispersed triangles, and so on.
Additionally, instead of using rows of stiffening elements running the length and/or width of a planar element, stiffening elements can be arranged into distinct cells. For example, in a first particular embodiment, stiffening embodiments can be arranged to form multi-sided, e.g., hexagonal or octagonal, cells in a honeycomb-like fashion.
In still other embodiments, stiffening elements can take the form of non-linear members. For example, instead of employing multi-sided cells, an array of stiffening elements having the form of circular rings might be employed. Still further, stiffening elements having complex lines, such as parabolas, can be employed.
While two-dimensional planar elements have been discussed so far, it should be appreciated that the above structural concepts can be applied to three-dimensional structures. For example, the concept of applying the crack-resistant stiffening elements described above can be applied to aircraft wings having simple curves or complex curves. For the purpose of this disclosure, the term “simple curve” can refer to any line that can exist in a single two-dimensional plane, e.g., a ring/circle or parabola. In contrast, a “complex curve” can refer to a line that cannot exist in a single two-dimensional plane, e.g., a spiral/helical curve.
By way of example, the side of a cylinder may be considered a planar element (planar referring to having a relatively small thickness compared to length and width if not strictly existing in a single plane) having a curve about one dimension, i.e., about the central axis in a cylindrical coordinate system. In this instance, a stiffening element can either traverse the length of the cylinder in a straight line (i.e., parallel to the central axis), or alternatively run about the axis of the cylinder in a ring with the flange running roughly parallel to the surface of the cylinder.
In situations where surfaces have a more mild curvature, such as those surfaces that might be found on an aileron, a stiffening element might be similarly made as with the cylinder example above with a flange curving to run roughly parallel to the surface of the aileron. However, in other embodiments, a flange might be made straight with the intermediate webbing changing in height to compensate for the curvature of the aileron surface.
For complex curves, the same concepts described above with regard to simple curves may be similarly applied.
Still further, while it may be desirable to monolithically integrate the stiffening elements and planar elements of FIGS. 1-4 , in various other embodiments, other processes of combining stiffening elements and planar elements can be used. For example, metal stiffening elements and planar elements might be attached (but not monolithically integrated) by use of rivets, bonding materials, spot welds, fasteners and so on.
FIG. 7 depicts a cross-section view of two monolithic structures 70 and 71 showing planar elements 76 and stiffening elements 72 joined at weld locations 74 . FIG. 8 is a flowchart outlining an exemplary technique for manufacturing fail-safe monolithic structures, such as those shown in FIG. 7 . The process begins in step 80 where one or more planar elements can be manufactured. While in various embodiments such planar elements can be flat sheets, such as those planar elements 76 shown in FIG. 7 , as discussed above such planar elements can take three-dimensional forms, such as portions of cylinders, spheres, etc as well as more esoterically curved forms. Control continues to step 82 .
In step 82 , stiffening elements designed to complement the planar elements of step 80 can be manufactured. The stiffening elements can be any of those described above with respect to FIGS. 1-4 or structures having similar properties and functionality. Control continues to step 84 .
In step 84 , the planar elements and stiffening elements of steps 80 and 82 can then be spatially arranged with respect to one another. Returning to FIG. 7 as an example, the planar elements 76 are appropriately arranged with respect to stiffening elements 72 by having their ends aligned at welding locations 74 . While FIG. 7 reflects stiffening elements running in a parallel direction, it should be appreciated that arranging planar elements and stiffening elements will change somewhat from embodiment to embodiment depending on whether the stiffening elements are to be arranged in crossing patterns, arranged into honeycomb structures, arranged in three-dimensional curved structures and so on. Control continues to step 86 .
In step 86 , the planar elements and stiffening elements are welded to one another. In the particular instance where the planar elements and stiffening elements are made of certain metals or plastics/resins, a welding process (e.g., friction-welding or arc-welding) or other usable process might be employed. For circumstances where structures are made of other materials, such as composites (e.g., laminates), certain plastics, ceramics, certain metals, glass etc, welding may take a number or combination of forms including the application of friction or heat, chemical bonding, ultraviolet curing or any other process that may be found useful or advantageous. Next, in step 88 the assembled structure(s) can be tested for overall structural integrity, integrity of the welds and so on. Control then continues to step 90 where the process stops.
While FIG. 7 depicts welds between planar elements and stiffening elements combined with sections of planar elements, it should be appreciated that the location of weld points can change from embodiment to embodiment. For example, referring to FIG. 9 , welding locations 94 are quite different for structures 90 and 91 being situated at the base of each webbing. For manufacturing embodiments envisioned by FIG. 9 , “spatially arrangement” of planar elements and stiffening elements takes a different form.
The many features and advantages of the invention are apparent from the detailed specification, and thus, it is intended by the appended claims to cover all such features and advantages of the invention which fall within the true spirits and scope of the invention. Further, since numerous modifications and variations will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation illustrated and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.
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A variety of a damage-tolerant monolithic structures are disclosed, such structures having a substantially-planar element integral with or welded to one or more stiffening elements. Each stiffening element can includes a first stiffening flange having a generally rail-like structure running along the length of the planar element and one or more webbings connected to the planar element and extending away from the planar element to the stiffening flange, wherein each webbing includes a row of integral holes running along the length of the webbing, the holes being in a shape designed to hinder the propagation of a crack in the monolithic structure.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to baby chairs which are suspendable from a table edge, and which can be removed and folded when not in use.
2. Prior Art
Portable baby chairs which can be attached to the edge of an ordinary table are well known. A variety of designs have been proposed for such chairs, and features which have proved advantageous include a cantilever arrangement for holding the chair to the table, a rigid seat bottom and back for greater chair strength, and foldability when the chair is not in use. Chairs embodying these features are described in U.S. Pat. No. 2,707,987 to Gibson, U.S. Pat. No. 3,052,500 to Hyde, U.S. Pat. No. 3,059,965 to Fornetti, U.S. Pat. No. 3,133,760 to Robinson, and U.S. Pat. No. Des. 200,850 to Palmer. Although the cantilever design allows the chairs to be conveniently hooked onto and unhooked from a table edge, it suffers from depending on a child's weight to create the friction needed to hold the chair stable against the table. If the child does not sit still, the chair can work its way back until one or both arm rests slip from the table, endangering the child. Thus, there is a need for a portable baby chair which can be better secured to a table top.
SUMMARY OF THE INVENTION
It is therefore the primary object of this invention to provide a portable baby chair which can be more reliably secured to a table top than could previously known cantilever style chairs. Another object is to provide a strong and stable chair which is convenient to use. This invention achieves these objects by providing a baby chair with a spring biased locking bar on each of the chair's under-table supports. The locking bars are pivoted at their lower ends to the supports. As the unfolded chair is slipped around the edge of a table top with the arm rests above and the supports below, the table top edge causes the bars to rotate backward against the spring force. The top ends of the bars, urged by their springs against the undersurface of the table, follow the pivoted bottom ends of the bars as the supports are swung under the table. Thus, the bars do not hinder hanging the chair from a table. However, once the chair is in place, pushing the chair away from the table causes the tops of the locking bars to dig in to the undersurface of the table and to hold the chair stationary. The locking bars are covered by gripping material for a better hold. When desired, the chair is easily removed from the table by grasping each of the bars and pulling it down from the table undersurface.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of the chair;
FIG. 2 is a side elevation of the chair showing how it is slipped around a table edge;
FIG. 3 is a side elevation detail of one of the locking bars;
FIG. 4 is a rear elevation of the chair; and
FIG. 5 is a perspective view showing the chair folded for storage.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIGS. 1 and 2, the baby chair 10 may be suspended from the edge of an ordinary table 100. Chair 10 comprises a rigid seat bottom 12 and a rigid seat back 14, both made of suitable material such as plywood and foam padding covered with wipe-clean plastic. A safety harness 16 made, for example, of nylon webbing with a buckle 17 insures that a child does not slip out of the chair, which is normally suspended several feet above a floor on the edge of table 100. Aside from seat bottom 12, back 14, harness 16, table grips 25, 27, 45, 47, 55, and 57, and pivot spacers 19, the rest of the chair is made of metal. A pair of under-table supports 20 and 22 extend from respective rear corners, along the sides, and past the front corners, of seat bottom 12, and turn upward to end in vertical table-abutting sections 24 and 26. Seat bottom 12 is fixedly attached to and supported by supports 20 and 22. Making supports 20 and 22 from a continuous piece of tubular metal including section 21 (FIG. 4) around the back increases the chair's strength and, in particular, helps keep it from twisting or tilting sideways.
A pair of plates 30 and 32 are fixed by rivets, for example, to seat back 14, and each extends forward in a vertical plane parallel to the sides of the chair. A U-shaped seat back reinforcement 15 (FIGS. 2 and 4) may be provided to strengthen the chair, in which case plates 30 and 32 are preferably attached to seat back 14 by way of rivets 18 through reinforcement 15.
A pair of arm rests 40 and 42 rotate relative to plates 30 and 32 by way of plate pivots 41 and 43 respectively. Arm rests 40 and 42 extend forwardly parallel to the side edges and past the front edge 13 of seat bottom 12 to end in table tangent sections 44 and 46. The arm rests 40 and 42 may also be connected in a continuous piece including section 48 as shown in FIG. 4.
Supports 20 and 22 are suspended from arm rests 40 and 42, respectively, by a back pair of vertical links 60 and 62 and by a front pair of vertical links 70 and 72, respectively. The links are connected to the arm rests by pivots 41, 43, 76 and 77, and to the supports by pivots 61, 63, 71 and 73. The pivot connections allow the chair to be folded for storage as in FIG. 5 with the arm rest 40, support 20, and links 60 and 70 (and of course the corresponding members on the hidden side) forming a parallelogram, and to be unfolded for use as in FIG. 1 with the named members more rectangularly disposed.
Diagonal links 64 and 65 help to reinforce chair 10 from being deformed by a child's weight, but otherwise do not constrain the chair's folding action. Rather, diagonal links 64 and 65 couple the tilt of seat back 14 to the shape of the parallelogram structure defined by front links 70, 72, rear links 60, 62, arms rests 40, 42 and under table supports 20, 22. Thus, as seat back 14 is moved towards or away from seat 60, 62, 70, 72 and supports 20, 22 to pivot corresponding amounts. See FIGS. 2 and 5. Diagonal link 64 is connected to plate 30 and to link 70 by pivots 34 and 74 respectively, and likewise diagonal link 65 is connected to plate 32 and to link 72 by pivots 35 and 75 respectively.
As shown in FIG. 2, chair 10 is unfolded for use and slipped around the edge of a table 100. Any ordinary table less than 2" thick can be used without modification, although there must be adequate clearance for the child's legs between the seat front edge 13 and the lower corner and any panel (not shown) on table edge 102. A glass topped or otherwise fragile table may not be strong enough, and a pedestal table might tip over. The chair is suspended by cantilever action when a child's weight pulls the arm rest tangent sections 44 and 46 down on points near the edge 102 of table top 101, and the table-abutting sections 24 and 26 of the support bars bear upward on the underside 99 of the table at points further from table edge 102 than the points reached by arm rest sections 44 and 46.
Locking bars 54 and 56 are attached to supports 20 and 22 by pivots 50 and 52 respectively. Bars 54 and 56 pivot within the limits imposed by bar angles 58 and 59. Biasing springs 51 and 53 urge the bars towards the table abutting ends 24 and 26 of the supports. When the seat is being installed on a table top 100, table edge 102 pushes locking bars 54 and 56 against springs 51 and 53. Obtuse angle theta (FIG. 3) allows the bars to slide by the under surface 99 of the table. However, once the chair is in place, springs 51 and 53 maintain the locking bars against the table, and pushing or pulling chair 10 away from table 100 causes the locking bars 54 and 56 to dig in to the table underside 99 at acute angle phi.
To help keep chair 10 stationary relative to table 100, while protecting table surfaces from being scratched, non-abrasive frictional coverings such as plastic cups 25 and 27, 45 and 47, and 55 and 57 are provided respectively for the ends of table abutting sections 24 and 26, arm rest tangent sections 44 and 46, and locking bars 54 and 56.
When a chair 100 is in use, the child's weight keeps the chair unfolded to the limit imposed by arm rest stops 31 and 33, which are part of, and at right angles to the rest of, plates 30 and 32 respectively. A safety pin 36, shown locked in FIG. 1 and unlocked in FIG. 5, insures that the chair is locked open. Safety pin 36 has a pull knob from which a shaft extends through a hole in arm rest 40 and into a hole 37 in plate 30. A spring (not shown) inside the arm rest holds the pin in plate hole 37 until the shaft is retracted by pulling the knob.
Details have been disclosed to illustrate the invention in a preferred embodiment of which adaptions and modifications within the spirit and scope of the invention will occur to those skilled in the art. The scope of the invention is limited only by the following claims.
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A portable baby chair 10 suspendable from the edge of an ordinary table 100 and which has spring biased pivoted locking bars 54, 56 on the chair's under table supports 20, 22 to engage the underside 99 of the table top and prevent the chair from slipping.
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This is a Continuation-in-part of U.S. Ser. No. 09/090,541 filed Jun. 6, 1998, now abandoned.
This invention relates to a leveling device which is particularly suitable for leveling and/or aligning electric components such as plug connector receiving receptacles, switches and combinations of such, arranged in an electrical outlet box.
BACKGROUND OF THE INVENTION
Electric outlet boxes are commonly installed on vertical walls throughout modern buildings. Such outlets boxes are generally intended for mounting electric components such as plug connector receiving receptacles, switches and/or combinations thereof to provide necessary assemblies for the convenient access of the occupant. Typically such outlet boxes have standard sized threaded holes arranged in standard spaced alignment at opposite sides thereof for mounting one or more components, with plug receiving receptacles and/or switches having one or more oblong holes arranged at opposite ends thereof which generally correspond and mate with the threaded holes of the outlet box. The components are mounted to the outlet box through screws which are commonly inserted through the oblong holes of a component to the threaded holes of the box for securely mounting a component to the outlet box.
The outlet boxes are generally mounted into or flush with the surface of the wall such that they cannot be easily moved for re-alignment, and generally are initially aligned to a generally vertical alignment or “vertical level” in relation to vertical lines of the building. Outlet boxes are visible, but necessary contrivances on the walls of the building and to make them less conspicuous are generally hidden by cover plates which have standard sized openings arranged to surround necessarily visible switch handles or plug receivers of the plug receiving receptacles. Such cover plates are generally sized to extend beyond the borders of the outlet box so as to cover the opening in the wall for access to the outlet box and provide a finished look to the assembly. The cover plates are generally screw mounted to the plug connector receiving receptacle and/or switch, which in turn is/are mounted to the outlet box.
Thus, the electrician who strives to assure that the assembly has a finished vertically level appearance, must first assure that the components are mounted to the outlet box in a vertically level arrangement by manipulation of mounting screws within the oblong holes of the components. When there is more than one receptacle, switch or combination of components, each must be properly spaced from the other to enable appropriate alignment and mating of the switch handles and or plugs with the corresponding holes in the cover plate.
In the past, the electrician has generally relied upon his/her visual acumen for appropriate mounting of the components and his/her ability to accurately visually predict a suitable vertical alignment and appropriate spacing among components. The problem with such is that all electricians are not equal in capability and since they must work close to the outlet assembly when doing the necessary manipulation and accurate viewing of vertical alignment is best done from a far perspective, alignment is a hit-or miss proposition. The result is that the electrician generally ends up availing the services of another to view the vertical alignment from a far perspective while he/she adjusts the components or viewing appearance and spaces the components through a trial and error process.
An object of the present invention is to provide an electricians leveling device which can be conveniently used to level standard components of a outlet box.
It is a further object of the invention to provide an electricians level which can be conveniently used to accurately space components in a multiple component outlet box.
It is another object of the invention to provide an electricians level which is convenient to use and has multiple utilities.
These and other objects of the invention will become apparent in the following recitation of the invention.
SUMMARY OF THE INVENTION
The method of the invention is to utilize a leveling means to ascertain the vertical and/or horizontal level of components of an outlet box, by using the female bar slots of a plug receiving receptacle component as a base level reference platform. Plug receiving receptacle components generally comprise two spaced apart plug receivers. Each of the plug receivers in turn generally comprise two, spaced apart, generally parallel female bar slots, arranged to accept corresponding flat bar prongs of a plug connector to complete a standard AC current circuit, and a rounded ground slot which is arranged offset from the parallel bar slots. The parallel female bar slots of both plug receivers in a receptacle component are arranged in generally parallel aligned symmetry with a central axis through the oblong mounting holes of the receptacle, and vertical or horizontal alignment of either of the parallel female bar slots of a plug receiving receptacle, automatically vertically or horizontally aligns the entire receptacle.
In the present invention, a device is provided comprising opposing, generally parallel, generally rectilinear male bar prongs which are arranged to insert into corresponding female bar slots of one of the plug receivers of a plug receiving receptacle. A spirit or other suitable level is provided which is arranged to designate a horizontal level when the parallel male bar prongs are disposed around a vertical axis.
Thus, in the method of the invention the user loosely mounts a plug receiving receptacle in an outlet box, plugs the device of the invention into one of the plug receivers of the receptacle, and by manipulating the device aligns the receptacle to a vertical position as indicated by a horizontal alignment designation of a spirit level bubble or electronic level indicator means. The mounting screws are then tightened to fix the receptacle to a desired aligned position. Since cover plates of outlet boxes are manufactured to standard openings in standard spaced positions, the standard plug receiving receptacle, fixed to the standard outlet box, serves as a base level reference platform from which all measurements and alignments of all other components can be derived.
Thus, in accord with the method of the invention a device having a housing which is shaped and formed to have reference means such as shoulders, edges and the like which are standard measured distances from the female bar slots of the first fixed base level reference, are representative of points of alignment for other components such as additional plug receiving receptacles, one or more switches and the like.
The device of the present invention comprises the combination of a leveling means, preferably spirit leveling means, and at least one plug connector having two, spaced apart, generally parallel, generally flat male bar prongs aligned to matingly insert into corresponding parallel female bar slots of a standard AC current plug receiving receptacle component. The level means of the device is arranged such that it provides a visual and/or audio indication of horizontal alignment when the parallel flat bar prongs are arranged along vertical axes.
The device of the invention generally comprises a housing, from which the generally parallel, flat bar prongs extend on one side, the housing being sized and shaped for convenient insertion of the flat bar prongs into one outlet of a plug connector receptacle. The leveling means is mounted to the housing, preferably built into the housing, on a side adjacent and/or opposite to the side comprising the flat bar prongs.
In a preferred embodiment of the assembly of the invention, the housing is generally rectilinear and formed from a molded plastic or the like. The bar prongs can be of any suitable electrically conductive and/or non-conductive material, but generally are of a conductive metal, being attached to the housing by molding the plastic housing around ends thereof, with opposite ends of the flat prongs extending from a side or end of the molded housing. When the bar prongs are of a conductive material, they are insulated separate from each other to prevent short circuiting of the plug receiver. A spirit or other suitable level is generally molded into the housing, at an opposite and/or adjacent side thereof, arranged to provide a ready view the level indicator such as a bubble, light, meter and the like when the prongs are inserted into a prong receiving receptacle.
One or more spirit or other levels can be comprised in a housing and generally it is convenient to have at least two levels arranged to indicate level perpendicular to each other. In such arrangement, a first level will indicate vertical alignment of the parallel bar prongs, e.g. the most popular vertical alignment of a receptacle plug; while a second level will indicate horizontal alignment of the parallel bar prongs, e.g. a less popular but still common horizontal alignment of a receptacle plug.
In an embodiment of the invention, the housing comprises internal wiring from the parallel bar prongs which are enabled to connect and/or comprise circuitry to a meter, light or the like for testing circuit continuity and the like. In a preferred embodiment a molded elastomeric housing comprises a visible light emitting source, which is activated through internal wiring upon insertion into the plug receiving receptacle and completion of a circuit among the parallel bar prongs. In a still further embodiment, an indicator, meter or the like is activated upon detection of a completed circuit.
In another embodiment of the invention, the housing comprises surfaces, edges, shoulders or the like which are dimensioned from the parallel bar prongs in standard reference distances to enable alignment of other components which may be arranged in the outlet box. For example, in one embodiment, the device housing is dimensioned to a width wherein upon insertion of the parallel bar prongs into a first plug receiving receptacle, a shoulder on a surface along the width of the housing, will abut the edge of a face of a second plug receiving receptacle at a standard prescribed distance corresponding to alignment with standard cover plate openings. Similarly, a shoulder and/or edge of the housing will be dimensioned to abut a handle or perimeter shoulder of a switch at a standard prescribed distance corresponding to alignment with standard combined switch and receptacle cover plates. In a preferred embodiment, the side of the device housing comprising the male bar prongs, comprises a raised curved shoulder spaced a standard distance from the male bar prongs which is arranged to generally engage a rounded edge of an adjacent receptacle receiver at a distance corresponding to the spaced openings of a multiple plug receptacle cover, while the side itself continues to extend to an edge corresponding to the spaced standard distance from the male bar prongs to the edge of a spaced opening of a switch handle of a combination receptacle and switch cover plate. Thus, the device enables ready reference location and level of a second, third, etc., receptacle(s) in a multiple receptacle outlet box and ready reference location and leveling of a switch in a combination receptacle/switch outlet.
In another embodiment, a molded housing comprises a deep slot sized for convenient insertion of a switch handle for quick determination of switch level in a non-receptacle containing outlet box. The slot can be of variable stepped widths, depths and/or lengths for various different switch handles, or there can be multiple slots of different dimensions and the like. In a preferred embodiment, the slot(s) is contained in a side of the device adjacent the male bar prongs and the side extends to an edge corresponding to the spaced standard distance between spaced opening of switch handles of a multiple switch cover plate.
In still further embodiments, the device of the invention comprises, a narrow slot or the like into which tabs of a switch or receptacle can be inserted to be bent for removal, or multiple other combination components useful to the electrician in performing jobs associated with the installation of components in an outlet box.
For a fuller understanding of the device of the present invention, reference should be made to the following detailed description taken in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a top plan view of an electricians level of the invention.
FIG. 2 is a right side plan view of the electricians level of FIG. 1 .
FIG. 3 is a left side plan view of the electricians level of FIG. 1 .
FIG. 4 is a front plan view of the electricians level of FIG. 1 .
FIG. 5 is a rear plan view of the electricians level of FIG. 1 .
FIG. 6 is a diagrammatic view of the circuit comprising a current indicator of an electricians level of the invention.
DETAILED DESCRIPTION OF THE INVENTION
Referring now to FIGS. 1-5, therein is illustrated a device of the invention wherein body 10 , comprising top surface 10 a , rear surface 10 d , front surface 10 e and side surfaces 10 b and 10 c , is illustrated as a molded resilient elastomeric unit. Spirit level 11 is mounted at about the edge of front surface 10 e and top surface 10 a of the unit, and spirit level 12 is mounted at about the edge of front surface 10 e and left side surface 10 c of the unit, the arrangements of the levels being such that a leveling bubble can be observed from the front, top and/or side surfaces of the unit through a 90° rotation of the unit. In addition, spirit level 12 is arranged such that the curvature of the level is inclined toward rear surface 10 d , sufficient to enable visual determinations of level in respect to side surface 10 b.
Rear surface 10 d of the unit comprises parallel male bar prongs 13 and 13 a , which are sized to insert into mating female slots of a receiving plug (not shown). The bar prongs are formed from an electrically conductive metal and extend into the molded unit and are held in place by the molded unit. Curved shoulder 14 is arranged on rear surface 10 d , with its interior curved surface 14 a generally sized and dimensioned to engage a standard curved edge of a standard plug receiver of a standard plug receiving receptacle. The distance “d 1 ” illustrated in FIG. 5 corresponds to a standard measured distance, of about 2 cm, measured from male bar prong 13 a to a standard adjacent opening edge of a standard cover for a dual plug receptacle outlet box. Distance d 2 , illustrated in FIG. 5 corresponds to a standard distance of about 3 cm, measured from male bar prong 13 a to a standard rectangular surround shoulder of a switch. Rectilinear surround shoulders are generally standard components of switches and are sized and dimensioned to mate into a standard rectilinear opening of a standard cover having an opening for a switch receptacle in a combined switch plug receptacle installation.
Slot 15 , in side 10 b of the unit is illustrated as being arranged near the edge among top surface 10 a and side surface 10 b , and as being of stepped width, beginning with a greater width corresponding to distance d 3 at the surface of side 10 b to a narrower width of d 4 within the interior elastomeric mass of the unit body. Switch handles are generally rectilinear shaped and of two different standard widths, a wide width d 3 , which is generally the standard width of lighted switch handles and a narrower width d 4 , which is a generally standard width of non-lighted switch handles. In the illustrated embodiment, the stepped slot is molded into the unit, enabled to receive either switch handle and the elastomeric unit, having a thinner wall at one side of the slot, tends deform to snugly hold the handles flush against the thicker wall, in an axis parallel to the male bar prongs.
Light 17 , comprises a small light emitting source, which is mounted into the elastomeric unit and completes a circuit among metal bar prongs 13 and 13 a.
In the overall method of use of the device of the invention, the rear surface of the unit is plugged into mating female slots of a first plug receiver of a plug receiving receptacle and the receptacle is aligned by adjusting the mounting screws of the component by means of the bubble indicator of spirit level 11 if the wall mounted outlet box is arranged to hold components vertical, or spirit level 12 if the wall mounted outlet box is arranged to hold components horizontal. Wall mounted outlet boxes arranged to hold components horizontal are not very common, and it is extremely rare that such arrangement holds more than one component or even a component other than a plug receiving receptacle. In the case of a horizontal arrangement containing two parallel plug receiving receptacle components, the lower receptacle is fixed to appropriate horizontal alignment using spirit level 12 and the distance to the upper receptacle is fixed in parallel, properly spaced alignment by engaging it against shoulder 14 on face 10 d of the unit.
In the case of a vertical arrangement of multiple components in a wall mounted outlet box, a right most first receptacle is adjusted and fixed to appropriate vertical alignment by plugging the rear surface of the unit into mating female slots of one of its plug receivers and the receptacle is aligned by adjusting the mounting screws of the component by means of the bubble indicator of spirit level 11 . A second receptacle is spaced an appropriate distance to the left of the first receptacle and in parallel alignment by engaging it against shoulder 14 and then checked and/or further adjusted for vertical by plugging the unit into a plug receiver of the second receptacle. The process is repeated for third, fourth or more receptacles as may be installed into the outlet box.
In another outlet box arrangement, a first right most plug receptacle is fixed to appropriate vertical alignment using spirit level 11 and the spaced distance left to a switch component is aligned using edge 16 of the unit to engage the surround shoulder of a switch at the appropriate distance and vertical alignment. In double switch arrangements, wherein two switches are comprised in a double plug receptacle type surround, the alignment and spacing of the switches to the plug receptacle is ascertained using curved shoulder 14 of the unit.
In the case of a vertical arrangement of two or more switch components, a first right side switch is fixed to appropriate vertical alignment by inserting the switch handle in slot 15 and using spirit level 12 to ascertain vertical alignment of the switch. A second switch is mounted to the left of the first switch, the distance to the next switch handle being determined using standard distance d 5 to the edge of the side lob with the bottom surface of the unit (not shown), engaging a shoulder of the rectilinear surround of the second switch handle, and so forth mounting each subsequent switch to the left of the previous switch as appropriate in standard spaced vertical alignment.
FIG. 6 illustrates typical circuitry for determining continuity comprised in a device of the present invention. Therein, an embodiment of the device is illustrated as comprising two parallel male bar prongs, 23 and 23 a , and a rounded ground prong 24 . The unit comprises three light emitting units sources 25 , 26 and 27 , one comprising a completed circuit “A” among the rounded ground plug and a first male bar prong, another a completed circuit “B” among the second male bar prong and the rounded ground prong, and the third a completed circuit “C” among the two male bar prongs for ascertaining continuity of a live wired receptacle.
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A device for leveling a plug receiving receptacle in an electric outlet box is disclosed which comprises a surface having spaced apart opposing male bar prongs arranged along generally parallel axes extending about perpendicular from the surface, arranged to insert into corresponding female bar slots of an electric plug receiver and level means, arranged to indicate horizontal and vertical level of an axis perpendicularly intersecting the parallel bar prong axes.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to the general art of ladders, and to the particular field of accessories for ladders.
[0003] 2. Discussion of the Related Art
[0004] Many tasks require the use of an extension ladder to complete. Just about any work on or near the ceiling of a room will require a ladder.
[0005] Using a ladder while performing a task may require skill, balance and dexterity. These traits can, and are, generally acquired by workers and craftsmen. However, no matter how proficient a worker is, he must still have some part of his concentration directed to maintaining his balance on the ladder while competing a task.
[0006] For example, a paper hanger must balance on a ladder while feeding paper from a roll, applying adhesive, and keeping the paper in place. While many paper hangers successfully achieve these goals, it would make their jobs easier if one or more of these tasks could be carried out by an accessory.
[0007] Therefore, there is a need for an accessory for a ladder that will permit a worker to direct most of his concentration to completing the task.
[0008] More specifically, there is a need for an accessory for a ladder that will assist a paper hanger in directing as much of his concentration on the task of hanging paper as possible.
[0009] Any accessory that is intended to make a task easier should not require a great deal of work to set up, or its objective will be vitiated. Therefore, there is a need for an accessory for a ladder that will assist a paper hanger in directing as much of his concentration on the task of hanging paper as possible and which is easy to assemble and to disassemble from a ladder.
[0010] To be most effective, any accessory that is intended to hold work items on a ladder must hold those items in the most convenient location on the ladder where those items will be easily accessible to a worker balancing on the ladder. Otherwise, the objectives of the accessory may be defeated.
[0011] Therefore, there is a need for an accessory for a ladder that will assist a paper hanger in directing as much of his concentration on the task of hanging paper as possible and will locate the items needed for the task in a position that is most convenient for the worker.
PRINCIPAL OBJECTS OF THE INVENTION
[0012] It is a main object of the present invention to provide an accessory for a ladder that will permit a worker to direct most of his concentration to completing the task.
[0013] It is another object of the present invention to provide an accessory for a ladder that will assist a paper hanger in directing as much of his concentration on the task of hanging paper as possible.
[0014] It is another object of the present invention to provide an accessory for a ladder that will assist a paper hanger in directing as much of his concentration on the task of hanging paper as possible and which is easy to assemble and to disassemble from a ladder.
[0015] It is another object of the present invention to provide an accessory for a ladder that will assist a paper hanger in directing as much of his concentration on the task of hanging paper as possible and will locate the items needed for the task in a position that is most convenient for the worker.
SUMMARY OF THE INVENTION
[0016] These, and other, objects are achieved by an accessory that includes a trigger-operated clamp, a paper supporting roller, a masking tape holder, a paper cutter, and a tape cutter.
[0017] The accessory is easily clamped onto a rail of an extension ladder and will support paper and tape in position to be easily reached and easily manipulated by a worker balancing on the ladder. After a job has been completed, the accessory embodying the present invention is easily removed from the ladder.
BRIEF DESCRIPTION OF THE DRAWING FIGURES
[0018] FIG. 1 is a perspective view of an accessory for use on a ladder during a paper hanging operation.
[0019] FIG. 2 is a side elevational view of an accessory for use on a ladder during a paper hanging operation.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0020] Other objects, features and advantages of the invention will become apparent from a consideration of the following detailed description and the accompanying drawings.
[0021] Referring to the Figures, it can be understood that the present invention is embodied in an accessory 10 for use on a ladder to support paper and tape rolls on the rail of the ladder in a position that is convenient to a user.
[0022] Accessory 10 comprises a central support bar 12 which has a first end 14 , a second end 16 , a first side wall 18 , a second side wall 20 , and a longitudinal axis 22 which extends between first end 14 and second end 16 .
[0023] A tape roll-supporting unit 26 is mounted on second end 16 of central support bar 12 . Tape roll-supporting unit 26 includes an axle 30 mounted on support bar 12 and which extends between first and second side walls 18 and 20 of support bar 12 and transversely to longitudinal axis 22 of the support bar 12 . A first tape roll holder 32 is rotatably mounted on the axle 29 adjacent to first side wall 18 , and a second tape roll holder 34 is rotatably mounted on axle 30 adjacent to second side wall 20 of the support bar 12 .
[0024] Tape mounted on the tape roll-supporting unit 26 will be fed off the rolls in a manner known to those skilled in the art.
[0025] A tape cutter element 40 is mounted on support bar 12 and includes a first end 42 located adjacent to first side wall 18 of the support bar 12 , a second end 44 located adjacent to second side wall 20 of the support bar 12 , and a longitudinal axis 46 which extends between first end 42 and second end 44 of tape cutter element 40 and which is oriented to extend transversely of longitudinal axis 22 of support element 12 . A cutting edge 48 is on tape cutter element 40 and is used to cut lengths of tape in a manner known to those skilled in the art.
[0026] A paper roll holder element 50 is mounted on supporting bar 12 adjacent to first end 14 of the supporting bar 12 . Element 50 includes a mounting bolt 52 fixed to supporting bar 12 , a base element 54 in abutting contact with second side wall 20 of supporting bar 12 and is fixed to mounting bolt 52 .
[0027] A roller element 56 is rotatably mounted on mounting bolt 52 and paper rolls are supported on the roller element 56 in a manner known to those skilled in the art.
[0028] A paper control arm 60 has a first end 62 pivotally fixed to tape cutter element 40 and a second end 64 located adjacent to roller element 56 . As can be understood from the Figures, paper roll holder element 50 extends parallel to tape cutter element 40 .
[0029] A paper cutting blade 70 is mounted on first end 14 of supporting bar 12 and includes a first end 72 fixed to supporting bar 12 , a second end 74 , and a longitudinal axis 76 which extends between first end 72 and second end 74 of paper cutting blade 70 and which is oriented to be parallel to paper roll holder element 50 and to extend transversely to longitudinal axis 22 of supporting element 12 .
[0030] A paper cutting edge 78 is located on paper cutting blade 70 to cut paper drawn thereover in a manner known to those skilled in the art.
[0031] A ladder attachment unit 80 includes a main bar 82 slidably mounted on tape cutter element 40 adjacent to second end 44 of the tape cutter element 40 . Main bar 82 includes a first end 84 , a second end 86 , and a longitudinal axis 88 which extends between first end 84 and second end 86 of the main bar 82 and is oriented transversely of longitudinal axis 46 of tape cutter element 40 and transversely of longitudinal axis 22 of supporting element 12 .
[0032] Main bar 82 further includes a first edge 90 which is a top edge when ladder attachment unit 80 is in use, a second edge 92 which is a bottom edge when ladder attachment unit 80 is in use, a stop element 94 on second end 84 of the main bar 82 , and a first ladder-engaging clamp element 96 located on first end 84 of the main bar 82 .
[0033] A handle unit 100 is mounted on main bar 82 and includes a hand-held element 102 having a bore 104 defined therethrough and through which main bar 82 is slidably accommodated. Unit 100 further includes a trigger element 106 pivotally mounted on hand-held element 102 , and a second ladder engaging-clamp element 108 on the hand-held element 102 . Second ladder-engaging clamp element 108 is oriented to face first ladder-engaging element 96 with a rail of a ladder interposed therebetween when ladder attachment unit 10 is in use.
[0034] A mechanism 120 , such as a ratchet and pawl mechanism, or other such mechanism that is known to those skilled in the art, connects trigger element 106 to main bar 82 of ladder attachment unit 80 in a manner such that operation of the trigger element 106 causes the main bar 82 to move first ladder-engaging clamp element 96 toward second ladder-engaging clamp element 108 to clamp the rail of the ladder therebetween and mount unit 10 on the rail of the ladder.
[0035] Operation of unit 10 can be understood by one skilled in the art based on the teaching of the foregoing disclosure, and thus will not be discussed in detail. Unit 10 is located on the rail of a ladder in a chosen position, trigger element 106 is operated to draw clamp element 96 toward clamp element 108 and clamp the rail of the ladder therebetween. Paper is mounted on unit 50 and tape on unit 26 . Paper is drawn over cutting edge 76 and cut when a desired length of paper is drawn. Tape is drawn off tape rolls and cut using cutting edge 46 for use with the paper. When a job is completed, unit 10 can be disassembled from the ladder and moved to a position convenient for the next job.
[0036] It is understood that while certain forms of the present invention have been illustrated and described herein, it is not to be limited to the specific forms or arrangements of parts described and shown.
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An accessory includes a handle-operated clamp and is mounted on a rail of a ladder, such as an extension ladder, to hold paper and tape in position to be easily accessed by a worker balancing on the ladder.
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FIELD OF THE INVENTION
This invention relates to a device which provides a directed beam of light for alignment of another device, and more specifically, to a laser light source which is incorporated within the handle of a surgical light wherein the light handle itself acts as a pointing device to properly orient the surgical lights on a surgical area.
BACKGROUND OF THE INVENTION
Surgical lights are used in surgical procedures to provide the appropriate amount of illumination so that a surgeon and other operating room personnel can clearly see the surgical area. In any surgical procedure, it is critical that the surgeon and other operating room personnel have a clear unobstructive view of the surgical area in order that the surgical procedure be carried out without distractions created by poor lighting conditions. Typically, surgical lights produce a light pattern that is brightest in the middle and then diminishes toward the exterior edges of the light pattern. At the exterior edges of the light pattern, the brightness may be reduced by as much as 80% in comparison to the middle of the light pattern. Human tissue, particularly human tissue within a surgical cavity, absorbs most of the light which it is exposed to. Accordingly, it becomes exceedingly difficult to adequately illuminate many surgical cavities. Additionally, many surgical cavities have overlapping tissues which create shadows thus making proper viewing of the surgical cavity more difficult. Surgical lights are extremely bright in comparison to most other lights used for indoor illumination. Typically, surgical lights have an output of 11,000 foot candles or higher. Also, surgical lights are commonly used in tandem to overcome any shadow effects which may be caused by a single light itself, or by conditions within the surgical cavity. The surgical lights must be properly oriented over the surgical area to maximize the illumination of the lights.
Although human tissue reflects very little light, the various coverings and wraps placed around the surgical area reflect much more light. In order to minimize glare produced by light reflected from the area surrounding the surgical area, it is desirable to exactly position the surgical lights so that the middle portion of the light patterns directly intersect with the surgical area. Improperly aligned surgical lights can result in inadequate illumination of the surgical area and increased glare. These conditions can produce eye fatigue and can disrupt efficient handling of the surgical procedure.
Most surgical lights have a single, centrally located handle which coincidentally defines the geometric center of the light and thus, the center of the light pattern produced by the light. The handle of a surgical light is made sterile by providing the handle with a disposable cover which is replaced after each surgical procedure. Operating room personnel to include the surgeon may grasp the light handle many times during a surgical procedure to best orient the light during the procedure.
An example of a disposable cover for a surgical light handle includes the U.S. Pat. No. 4,605,124. This reference also illustrates a common surgical light. This patent is hereby incorporated by reference for purposes of disclosing not only typical surgical lights, but also a light handle cover which is used to cover a centrally located light handle. Another example of a disposable cover for the light handle of a surgical light includes the U.S. Pat. No. 4,974,288. While these references disclose a single centrally located light handle, there are no means provided to directly aim the surgical light at its intended target.
SUMMARY OF THE INVENTION
From the foregoing, it is apparent that a need exists for having the capability to orient surgical lights on their intended target within the surgical area.
The invention disclosed and claimed herein provides an aiming device which is incorporated within the light handle to efficiently and quickly orient surgical lights. As further discussed below in connection with the preferred embodiment, a laser light handle is provided which combines a laser light source within the light handle of the surgical light. A directed beam of laser light is transmitted from the distal tip of the laser light handle by operating a switch which turns the laser light on or off. The laser light may be powered by a battery housed within the light handle, or solar power can be used to power the laser by incorporating a thin film solar panel mounted around the light handle. The solar panel receives light from the surgical light(s). The laser light beam is of a sufficient brightness which makes it clearly distinguishable from light produced by the surgical lights. In order to orient the surgical lights, the surgeon or other operating room personnel simply grasp the surgical light by the light handle, then adjust the positioning of the light to direct the laser light beam on the target. The laser light beam appears as a very bright spot of light on the target. Since the light handle is centered within the surgical light, the spot of laser light acts as a simple pointer to exactly align the light pattern of the surgical light on the target.
If the light handle is to be used in a sterile procedure, a light handle cover is used to cover the light handle. The light handle cover is modified to include a small opening which allows the directed beam of laser light to reach its target. The switch includes a unique arrangement on the exterior surface of the light handle which enables the user to easily activate or deactivate the laser light source. This switch may also be centered along identifiable exterior features of the light handle cover thus enabling the user to activate the laser light by touch alone, while keeping eyes centered on the target.
The proximal end of the light handle may include one or more adaptors which allow it to be used with different types of surgical lights. Accordingly, the light handle of this invention is not restricted to use with any particular type of surgical light.
While the invention disclosed and claimed herein has particular utility with respect to surgical lights, the invention herein also lends itself to use in many other fields. In any endeavor requiring the use of an illuminating light which needs to be centered over a particular work area, the light handle of this invention may be used to orient the illuminating light on its target. Because of its cylindrical shape, the light handle acts as a pointer which can be directed for aligning an illuminating light.
Various other advantages will become apparent in conjunction with the detailed description, taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view illustrating a pair of surgical lights used to illuminate a surgical area attended to by a surgeon and a surgeon's assistant, the surgical lights each incorporating the laser light handle of the invention;
FIG. 2 is a perspective view of the laser light handle of this invention, and an example of a light handle cover (in dotted lines) mounted over the light handle;
FIG. 3 is an exploded perspective view illustrating the details and components of the surgical light handle, and a perspective view of the light handle cover;
FIGS. 4 and 5 are enlarged elevation views of the switch which is used to activate/deactivate the laser light, and the switch activation members used to operate the switch;
FIG. 6 is another perspective view of the light handle, but incorporating a solar module as an alternate source of power for powering the laser light; and
FIG. 7 is a side elevation of the solar module separated from the light handle further illustrating the details thereof.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 illustrates the light handle of the invention 10 used in conjunction with surgical lights L which are mounted upon adjustable brackets B. As shown, a surgeon S and an operating room assistant A are conducting a surgical procedure on a patient P. The lights L are directed or pointed in alignment with a surgical area or site 14 . Light handles 10 are mounted to each light L, and are aimed directly at the surgical site 14 . Each of the light handles 10 can produce a directed beam of light 12 to the surgical site 14 which results in precise alignment of the surgical lights L. FIG. 1 also shows the simple manner in which the light handle L may be activated. As shown, the operating room assistant A simply reaches up and grasps the light handle 10 , and then selectively activates/deactivates the light handle 10 to produce the directed beam of light 12 to align the corresponding surgical light L onto the surgical area 14 .
It shall be understood that surgical lights L and brackets B represent common or generic surgical lights and the lights L are adjustable either by brackets B or some other known mechanical linkage. With respect to the specific style of lights shown in FIG. 1, each of the lights L include a housing 15 , an opaque central portion 16 which serves as a mounting structure for a corresponding light handle 10 , and an annular light emitting portion 17 which includes a plurality of lamps or other light emitting elements which illuminate the surgical area 14 in a round light pattern.
FIG. 2 illustrates the light handle 10 prior to mounting on the lights L, and a light handle cover 18 (illustrated in dotted lines) which may be mounted over the light handle 10 in order to provide sterile conditions for surgical procedures. The light handle cover 18 simply fits over the distal end of the light handle 10 , as further discussed below.
The light handle cover 18 can be a commercially available light handle cover which is then adapted for use with the light handle 10 of this invention. One example of a manufacturer who makes light handle covers includes Devon Industries, Inc. of Chatsworth, Calif. This company makes and sells a product known as the “Lite Glove”®. As used with the light handle of this invention 10 and as further discussed below, the light handle cover 18 includes an opening 100 formed at the distal end thereof which allows the directed beam of light emanating from the light handle to reach its target. The light handle cover 18 can be made of a plastic for a disposable type of light handle cover, or the light handle cover may be made of aluminum or some other known metal whereby the light handle cover is resterilizable for multiple uses.
Because of the cylindrical shape of the light handle 10 , and its symmetry with respect its longitudinal axis X—X, the light handle is well suited as a pointer for directing or pointing the directed beam of laser light onto a target.
Now referring to FIG. 3, the light handle 10 is illustrated to disclose its components. A distal adaptor 19 includes an adaptor housing 20 , and a threaded well 22 for receiving the threaded proximal end 108 of the light handle cover 18 . The opposite end of the distal adaptor 19 includes an external threaded portion 24 which may connect directly to a threaded well (not shown) within the central opaque area 16 of the light L. The threads 24 may be sized to fit the particular threaded well of the light L. Depending upon the type of light L used, the connection between the light handle and the light L may be a bayonet type connection, friction fit, or others. Thus, threaded portion 24 can be replaced with the desired type of fitting so to match the particular type of light L. The proximal end of the threaded portion 24 is capped or closed by a threaded proximal plug 26 which screws into internal thread (not shown) at the proximal end of the threaded portion 24 . As discussed below, an optional additional adapter 90 may also be used.
A battery housing 30 is provided distally of the distal adaptor 19 . The battery housing 30 is defined by a body 32 , an exterior threaded proximal end 34 which is received in another threaded well (not shown) within the bore of distal adaptor 19 positioned proximally of threaded well 22 . The housing 30 further includes an interior threaded distal end 36 . The battery housing 30 is cylindrical shaped, and includes a bore extending completely therethrough.
A battery 38 is provided for powering the laser light source 60 . The battery 38 is electrically connected to the laser source 60 via conducting strip 40 , battery connector 42 / 44 , and switch assembly 50 . Male portion 42 of the battery connector may be removably connected with female portion 44 of the battery connector. The male portion 42 of the battery connector includes a set of conductive clips 43 which mate with corresponding structure on the female portion 44 . The battery 38 simply fits between perpendicular extending contacts 45 of the conducting strip 40 . The battery 38 along with the conducting strip 40 and battery connector 42 / 44 are inserted within the bore of the battery housing 30 .
A distal cap 46 including threaded portion 48 is mounted over the distal end of the battery housing 30 . One or more conductors 56 interconnect switch assembly 50 with connector 42 / 44 . One or more conductors 56 may also interconnect the connector 42 / 44 with circuitry 64 of the laser light source 60 . The switch assembly 50 , in turn, connects directly to the laser light source 60 . When the light handle is assembled, the switch assembly 50 and a pair of switch activation members 70 are positioned between the laser housing 76 and the battery housing 30 .
Now also referring to FIGS. 4 and 5, the switch assembly 50 includes a pair of opposing micro-switches 52 which are mounted in opposing relationship on switch mounting board 54 . An example of an acceptable laser source 60 includes a Class III visible diode laser (3 volts, 5 milli-watts, 635 nanometers). One manufacturer of such lasers is Quarton Inc., of City of Industry, Calif. This type of laser represents one which will produce a very bright laser light which is bright enough to overcome and be distinguished from surgical lights; however, the laser is not of such an intensity that will result in damage to the tissue of a patient, so long as exposure of the tissue to the laser is only of short duration. This type of laser produces a very clear and bright spot of light on the target in which it is viewed. The laser source 60 includes a projection window 62 from which the directed beam of laser light is projected. Typically, this type of laser source 60 includes its own control circuitry, shown as the circuit board 64 .
The switch activation members 70 each include a pivot/rotation bore 72 , and a travel bore 74 . A plurality of screws 84 and bushings 86 are used to secure the components of the light handle. The distal cap 46 includes slots/cutouts 88 which receive corresponding screws 84 . The screws 84 extend through openings 89 in the distal cap 46 , through rotation bores 72 and travel bores 74 , and are then screwed into corresponding threaded wells (not shown) formed on the periphery of the laser housing 76 at the proximal end thereof.
The travel bores 74 are elliptical in shape. Force applied in the direction of force arrows F allow the switch activation members to pivot or rotate about the screws 84 in pivot/rotation bores 72 . The length or travel of the pivoting action is delimited by the available gap G between the interior edge of the bore 74 and the bushing 86 . The switch activation members 70 are aligned such that their internal contacting surfaces 75 depress the corresponding micro-switches 52 when force is applied, thus activating the laser source 60 to produce a laser light beam. When no force is applied, the activation members 70 return to their normally open positions as shown in FIG. 4 . One or both of these micro-switches 52 when depressed may activate the light source 60 .
The laser housing 76 is the most distal component of the light handle, and includes a cylindrical body 80 , a rounded tip 82 , and an opening 78 which allows the directed beam of light from the laser source 60 to pass therethrough.
Optionally, an additional adaptor 90 may be used to connect the light handle 10 to the desired surgical light L. Proximal adaptor 90 simply includes a threaded proximal well 92 for receiving the external threaded portion 24 , and external threaded portion 94 which can be modified in its size and thread configuration for connection to the desired type of surgical light. Because the construction of the distal adaptor 19 is somewhat more complex than the adaptor 90 (adaptor 19 also includes the set of internal threads for receiving the proximal end 34 of the battery housing) it may be more cost effective to use adaptor 90 and modify it for the particular type of surgical light used.
Now referring back to FIGS. 2 and 3, the light handle cover 18 is characterized by a handle portion 96 which may optionally include one or more exterior features such as ridges/slots 98 . These features of the handle portion 96 are easily identified by touch. As desired, the ridges/slots 98 may be aligned over one of the switch activation members 70 so that a user simply has to feel for the ridges/slots 98 , and then depress the light handle cover at or near the longitudinal location of the switch activation member 70 in order to activate/deactivate the laser light source. The opening 100 in the light handle cover allows the laser light source to pass therethrough. A shield 102 connects to the proximal end of the handle 96 , and extends substantially perpendicular thereto. In order to reduce the size of the light handle cover 18 when it is packaged for shipment, tabs or ears 104 are provided which engage flanges 106 , thus reducing the cross-sectional profile of the light handle cover. The light handle cover 18 is typically made of a plastic disposable material, and the shield portion 102 is of sufficient thinness which allows it to be bent so that tabs 104 may engage flanges 106 . FIG. 2 shows the distal end of the light cover 18 extending beyond the distal end of the light handle 10 , thus creating an offset or gap between the distal ends. This offset helps to prevent contamination that may enter through opening 100 from reaching the light handle 10 . Although the light handle 10 is not sterile, use of the same light handle 10 in multiple procedures might cause a contamination problem if the distal end of the light handle was exposed to contamination and the distal end was placed in close proximity to the distal end of the light handle cover 18 whereby the contamination could travel back out through opening 100 into the sterile field. As mentioned above, the light handle cover 18 is secured to the light handle 10 by engaging the threaded end 108 of the light handle cover with the threaded well 22 of the light handle.
Referring to FIG. 6, an alternate source of power may be used in the form of solar electric generating assembly 110 . The solar electric generating assembly 110 is a frusto-conical shaped component having a cylindrical shaped attachment flange 118 which mounts over adaptor housing 20 . Referring also to FIG. 7, the solar electric generating assembly 110 includes the frusto conical shaped housing 112 , a circumferential bead 114 , and a thin film solar module 116 which is mounted over the proximal facing surface of the housing 112 . As well as understood by those skilled in the art, the solar module 116 collects light thereon, and converts the light photons to electrical energy. The electrical charge created by the solar module 116 may be delivered to the switch assembly 50 by conductor 120 , and an integral male connector 122 which plugs into the female portion 44 of the original battery connector. Accordingly, the battery 38 , conducting strip 40 , and male portion 42 of the battery connector are removed to allow the male connector 122 to provide voltage for the laser source 60 .
Examples of commercially available thin film solar modules which may be used with the solar electric generating assembly 110 include various flexible solar modules as marketed and sold by Solar-World.com. A flexible solar module having a plastic substrate which is lightweight, flexible, and which produces a four volt/five milliamp output is adequate to power the laser source 60 .
If the solar module assembly 110 is used as a power source, the light handle cover 18 is still easily usable with the invention. The proximal facing side of the shield 102 simply abuts the bead 114 of the solar assembly 110 .
Preferably, the distal adaptor 19 , battery housing 30 , distal cap 46 , switch activation members 70 , and laser housing 76 are made of aluminum, stainless steel, or other commonly accepted metals used in surgical equipment. Aluminum is an excellent choice because it is lightweight and has high strength.
This invention has been described with respect to a particular disclosed preferred embodiment; however, it will be appreciated by those skilled in the art that various modifications and changes may be made within the spirit and scope of the invention.
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A light handle of an illuminating light is provided which produces a directed beam of light in order to precisely orient and align the illuminating light on a work area. Preferably, a laser producing light source is incorporated within the handle housing, and the directed beam of laser light projects from the distal end of the light handle. The laser light source may be battery powered, or may be powered by a solar panel mounted to the light handle; the illuminating light providing sufficient light to power the solar panel. To maintain sterility in a surgical environment, a light handle cover may be mounted to the light handle. For non-sterile applications, the light handle may simply be attached to the illuminating light without the light handle cover.
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BACKGROUND OF THE INVENTION
The invention relates to a circuit arrangement for operating a discharge lamp, provided with
input terminals for coupling to a supply voltage source,
means I coupled to the input terminals for generating a current through the discharge lamp from a supply voltage delivered by the supply voltage source,
a control circuit for controlling the operational state of the means I, comprising
means II for generating a signal S which is a measure of the value of an operating parameter,
an integrated circuit provided with
an input terminal T coupled to the means II,
means C for generating a first internal reference signal,
means E coupled to input terminal T for generating an internal signal S int derived from the signal S,
comparator means Comp provided with an output, a first input coupled to the means C, and a second input coupled to the means E, and
means III coupled to the output of the comparator means Comp for changing the operational state of the means I.
Such a circuit arrangement is known from U.S. Pat. No. 4,952,849 (hereby incorporated by reference). The signal S in the known circuit arrangement, which is a measure of the value of an operating parameter, is a signal which is a measure of the current through the discharge lamp (also referred to the lamp hereinafter). The control circuit achieves that the amplitude of the current through the lamp remains approximately constant. It is also possible to choose an alternative operating parameter such as, for example, the voltage across the lamp. If, for example, the discharge lamp fails to ignite after the circuit arrangement has been switched on, the voltage across the discharge lamp will rise to the point where the internal signal S int exceeds the value of the first internal reference signal. This activates the means III. The means III effect a change in the operating state of the means I such that this causes the voltage across the discharge lamp to drop. It can be achieved thereby that the voltage across the discharge lamp is not maintained at a high value by the circuit arrangement for a long period if the discharge lamp should fail to ignite. It is desirable in many cases not only to provide measures which ensure that the value of an operating parameter does not exceed a maximum admissible value (for a long period), but also to ensure that the same operating parameter cannot assume an undesirably low value. If the operating parameter is the voltage across the discharge lamp, a (too) low value of this voltage may point to a (too) high value of the current through the discharge lamp or a defect in a capacitor connected parallel to the discharge lamp. It may also be desirable, for example, to limit the voltage across the discharge lamp to a first maximum admissible value during ignition and to a second maximum admissible value during stationary lamp operation, which latter value must not be exceeded for more than a predetermined time interval. A change in the operational state of the means I is indicated, for example, by switching-off of the means I, if a maximum or minimum admissible value is exceeded. It is possible to design the control circuit such that the means II are coupled to only one input terminal of the integrated circuit, and that one and the same signal S int is compared with a first internal reference signal and with a second internal reference signal. Such a construction of the control circuit, however, makes it necessary to lay down the relationship between the two internal reference signals in the integrated circuit. The relationship between the two reference values, for example, the relationship between the minimum admissible value and the maximum admissible value of the operating parameter, is then also laid down in such a construction of the control circuit. The minimum admissible value and the maximum admissible value of an operating parameter, such as the voltage across the discharge lamp, however, are generally speaking dependent on specific properties of the discharge lamp and of the construction of the circuit arrangement. It is desirable for this reason to have a mechanism for setting these reference values independently of one another. This is possible through the use of two input terminals of the integrated circuit. These two input terminals are coupled to the means II in that case, and each of the input terminals is coupled to comparator means and means for generating a reference signal. Such a solution, however, requires a comparatively large number of input terminals, which renders the integrated circuit large and expensive. In addition, this solution often requires a comparatively large number of external components, so that the circuit arrangement becomes complicated and expensive.
SUMMARY OF THE INVENTION
The invention has for an object to provide a circuit arrangement of the kind mentioned in the opening paragraph with which it is possible to adjust two reference values of the signal S independently of one another, while the means II are coupled to only one input terminal.
According to the invention, a circuit arrangement of the kind mentioned in the opening paragraph is for this purpose characterized in that the means II are coupled to the input terminal T via an impedance P, and in that the integrated circuit is in addition provided with
means D coupled to the comparator means Comp for generating a second internal reference signal,
means IV for changing the amplitude of an electrical quantity G present at the input terminal T from a first to a second value, and for changing the operational state of the comparator means Comp from a first state to a second state, said comparator means Comp comparing the internal signal S int with the first internal reference signal in the first state and comparing the internal signal S int with the second internal reference signal in the second state.
The comparator means Comp are in the first state when the amplitude of the electrical quantity G has the first value, in which case the internal signal S int is compared with the first internal reference signal. This means that the signal S is compared with a first reference value derived from the first internal reference signal. If the amplitude of the electrical quantity G has the second value, the internal signal S int is compared with the second internal reference signal. This means that the signal S is compared with a second reference value derived from the second internal reference signal. Although the first and the second internal reference signal have been laid down in the integrated circuit, it is possible to adjust the first and the second reference value independently of one another by means of the impedance value of impedance P and the dimensioning of the means II.
The means III change the operational state of the means I whenever the signal S has passed one of these reference values.
The electrical quantity G may be the voltage present at the input terminal T, in which case the means IV are provided with means for changing the amplitude of the voltage present at the input terminal from a first value V1 to a second value V2. Preferably, the second value V2 is chosen to be zero. The integrated circuit may be of a comparatively simple construction in that case.
The electrical quantity G may alternatively be the current flowing through the input terminal. In that case the means IV are provided with means for changing the amplitude of the current flowing through the input terminal from a first value I1 to a second value I2. It is advantageous in this latter case for the means IV to comprise a first current source and a second current source, the first current source supplying a current whose amplitude is equal to the first value I1 and the second current source supplying a current whose amplitude is equal to the second value I2. Preferably, the second value I2 is chosen to be zero. The integrated circuit then can be of a comparatively simple construction.
Preferably, the means IV are provided with means IVa for periodically changing the amplitude of the electrical quantity G from the first value to the second value and vice versa at a frequency f and for periodically changing the operational state of the comparator means Comp from the first state to the second state and vice versa. It is possible in that case to repeat the comparison of the signal S with the reference values continuously and thus to monitor the relevant operating parameter during a longer period. If the means I comprise at least a switching element and means IVb for rendering the switching element conducting and non-conducting during lamp operation, the frequency with which the switching element is rendered conducting and non-conducting is preferably chosen to be equal to the frequency f, and the changes in amplitude of the electrical quantity G and in the operational state of the comparator means Comp take place in synchronism with the cycle in which the switching element is rendered conducting and non-conducting.
Good results were obtained with embodiments of the circuit arrangement according to the invention in which the impedance comprises an ohmic resistance.
A comparatively simple construction of the integrated circuit is possible if the first internal reference signal is equal to the second internal reference signal, and the means D are formed by the means C.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of a circuit arrangement according to the invention will be explained in more detail with reference to the accompanying drawing, in which:
FIGS. 1, 2 and 3 are diagrams of embodiments of a circuit arrangement according to the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In FIG. 1, K1 and K2 form input terminals for coupling to a supply voltage source. Circuit portion I in this embodiment forms the means I coupled to the input terminals for generating a current through the discharge lamp from a supply voltage delivered by the supply voltage source. The current through the discharge lamp is a high-frequency alternating current in this embodiment. A discharge lamp La is connected to respective output terminals of the means I.
Ohmic resistors R1 and R2 together with circuit portion IIa form the means II in this embodiment for generating a signal S which is a measure of the value of an operating parameter. The operating parameter is the amplitude of the AC voltage present across the discharge lamp La during lamp operation in this embodiment. Circuit portion IIa may comprise, for example, means for generating a DC voltage signal which is a measure of the rms value of the voltage across the discharge lamp. Another possibility is that circuit portion IIa comprises means for generating a DC voltage signal which is a measure of the sum of the amplitudes of the voltages across the discharge lamp in both directions. Ohmic resistor P in this embodiment forms an impedance P. The other circuit portions and components shown in FIG. 1 together form an integrated circuit IC. T is an input terminal of the integrated circuit IC which is coupled to the means II via ohmic resistor P. Circuit portion IVa together with switching element Sw1 and switching element Sw2 forms the means IV and at the same time means for periodically changing the amplitude of an electrical quantity G present at the input terminal from a first to a second value and vice versa and for changing the operational state of the comparator means Comp from a first state to a second state, said comparator means Comp comparing an internal signal S int with a first internal reference signal in the first state and comparing the internal signal S int with a second internal reference signal in the second state.
The quantity G present at the input terminal in this embodiment is formed by the voltage applied to the input terminal, having a first value V1 and a second value V2. A, B, C and D are circuit portions for generating, in that order, a voltage whose amplitude is equal to the first value V1, a voltage whose amplitude is equal to the second value V2, a voltage which in this embodiment forms the first internal reference signal, and a voltage which in this embodiment forms the second reference signal. Furthermore, the integrated circuit IC comprises a circuit portion E, two comparators Comp1 and Comp2, and a circuit portion III which in this embodiment forms the means III for changing the operational state of the means I when the signal S has passed a reference value which is derived from the internal reference signal. The circuit portion E in this embodiment forms means E for generating the internal signal S int which is derived from the signal S. The comparators Comp1 and Comp2 in this embodiment form the comparator means Comp.
Ends of the discharge lamp La are connected to respective inputs of circuit portion IIa. A first output of circuit portion IIa is connected to a second output by means of a series circuit of ohmic resistor R1 and ohmic resistor R2. A common junction point of ohmic resistor R1 and ohmic resistor R2 is connected to terminal Ts. Terminal Ts is connected to input terminal T via ohmic resistor P. Input terminal T is connected to a first main electrode of switching element Sw1. A second and a third main electrode of switching element Sw1 are connected to an output of circuit portion A and an output of circuit portion B, respectively. E is a circuit portion for generating a voltage which is proportional to the current through the input terminal T. An input of circuit portion E is for this purpose coupled to input terminal T. An output of circuit portion E is connected to a first main electrode of switching element Sw2. A second and a third main electrode of switching element Sw2 are connected to an input of comparator Comp1 and to an input of comparator Comp2, respectively. A further input of comparator Comp1 is connected to an output of circuit portion C, and a further input of comparator Comp2 is connected to an output of circuit portion D. Outputs of the circuit portion IVa are coupled to respective control electrodes of switching elements Sw1 and Sw2. This coupling is indicated with broken lines in FIG. 1. An output of comparator Comp1 is connected to an input of circuit portion III. An output of comparator Comp2 is connected to a further input of circuit portion III. An output of circuit portion III is connected to an input of circuit portion I.
The operation of the circuit arrangement shown in FIG. 1 is as follows.
When the input terminals K1 and K2 are connected to a supply voltage source, the means I generate a high-frequency alternating current through the discharge lamp from a supply voltage delivered by this supply voltage source during stationary lamp operation. Before the stationary lamp operation phase, the circuit portion I generates an ignition voltage across the discharge lamp La during the ignition phase. A signal S, which is generated by the means II and which is a measure of the amplitude of the voltage across the discharge lamp La, is present at terminal Ts both during the ignition phase and during stationary lamp operation. The circuit portion IVa periodically switches the integrated circuit from a first to a second state and vice versa by means of switching elements Sw1 and Sw2. In the first state, the input terminal T is connected to the output of circuit portion A, and the output of circuit portion E is connected to the further input of comparator Comp1. Voltage V1 is present at the input terminal T. In the second state, input terminal T is connected to the output of circuit portion B, and the output of circuit portion E is connected to the further input of comparator Comp2. Voltage V2 is present at the input terminal T. The outputs of comparators Comp1 and Comp2 are both low immediately after the circuit arrangement has been switched on. If the voltage present at the output of circuit portion E is higher than the first internal reference value in the first state, the output of comparator Comp1 will change from low to high, which activates the circuit portion III and changes the operational state of the circuit portion I. The following equation holds for the voltage S1 at terminal Ts if that current through input terminal T for which the voltage S int at the output of circuit portion E is equal to the first internal reference value is equal to I1:
S1=I1*(R)P+V1, (I)
in which (R)P is the resistance value of ohmic resistor P.
This voltage S1 is the first reference value of the signal S. The signal S is accordingly compared with the first reference value S1 in the first state, S1 being dependent on the current I1, which in its turn is determined by the first internal reference value formed by the output voltage of circuit portion C via circuit portion E. The operational state of circuit portion I is changed if the signal S exceeds the first reference value S1.
The output of comparator Comp2 changes from low to high, whereby the circuit portion III is activated and the operational state of the circuit portion I is changed, if in the second state the voltage S int present at the output of circuit portion E is lower than the second internal reference value. The following is true for the voltage S2 at terminal Ts if the current through input terminal T for which the voltage at the output of circuit portion E is equal to the second internal reference value is equal to I2:
S2=I2*(R)P+V2. (II)
This voltage S2 is the second reference value of the signal S. The signal S is accordingly compared with the second reference value S2 in the second state, S2 being determined by current I2 which in its turn is determined via circuit portion E by the second internal reference value formed by the output voltage of circuit portion D. The operational state of circuit portion I is changed if the signal S is lower than the second reference value S2.
The ratio I1/I2=y is a fixed one because the circuit portions E, C and D form part of the integrated circuit IC. If the desired ratio of the first and the second reference signals S1/S2 is x, substitution of x and y in equation I and equation II gives:
S1=x*(y*V2-V1)/(y-x)
S2=(y*V2-V1)/(y-x)
It is also true that:
R=(x*V2-V1)/((y-x)*I2)
The ratio of the resistance values of ohmic resistors R1 and R2 is chosen such that the signal S at terminal Ts reaches the value S1 when the voltage across the discharge lamp reaches its maximum admissible value. Given this ratio of the resistance values of ohmic resistors R1 and R2, the signal at terminal Ts will reach the value S2 when the voltage across the discharge lamp La reaches its minimum admissible value. The internal reference values I1 and I2 correspond to the external reference values S1 and S2 given the value of ohmic resistor R in accordance with the equation. It is thus possible to adjust the reference values S1 and S2 mutually independently to desired levels through a suitable choice of the resistors R1, R2 and R.
The embodiment shown in FIG. 1 can be substantially simplified. If the integrated circuit is so constructed that I1/I2=y is equal to 1, the first internal reference value will be equal to the second internal reference value. Only one circuit portion for generating the internal reference value is required in such an embodiment of the integrated circuit IC. Since the internal signal S int is to be compared with only a single internal reference value, the comparator means Comp need comprise only one comparator, and the switching element Sw2 is also redundant. A further simplification may be obtained in that the amplitude of voltage V2 is chosen to be equal to zero. Circuit portion B may now be formed in that the relevant main electrode of the switching element Sw1 is connected to ground potential. The integrated circuit IC can be of a comparatively simple construction as a result of this. Circuit portion I of the embodiment shown in FIG. I comprises a bridge circuit which contains two switching elements which are rendered conducting and non-conducting alternately at a high frequency f for generating the high-frequency current through the discharge lamp. A further advantage over the embodiment shown in FIG. 1 may be realized in that the switching element Sw1 changes the value of the voltage at input terminal T with the same frequency f, in synchronism with the cycle in which the switching elements in the bridge circuit are rendered conducting and non-conducting. The process of rendering the switching elements of the bridge circuit conducting and non-conducting gives rise to interference signals which are also present at terminal Ts and which accordingly can influence the value of the signal S. The interference generated by this switching, however, cannot influence the result of the comparison between the internal signal S int and the internal reference signal by the comparator means Comp if the switching of the switching elements in the bridge and in the integrated circuit is carried out in synchronism, and said comparison is carried out only in a time interval within which no switching takes place. FIG. 2 shows an embodiment of a circuit arrangement according to the invention in which the improvements mentioned in the present paragraph relative to the embodiment of FIG. 1 have been implemented. The control signal which controls both the switching elements of the bridge circuit and switching element Sw1 is generated by circuit portion III, which comprises the means III as well as the means IV in the embodiment shown in FIG. 2. An output of circuit portion III is for this purpose coupled to switching element Sw1. This coupling is indicated with a broken line in FIG. 2. The output of circuit portion III coupled to circuit portion I is coupled to control electrodes of the switching elements of the bridge circuit which forms a part of circuit portion I. Compared with the embodiment shown in FIG. 1, circuit portion B, circuit portion D, comparator Comp2, and switching element Sw2 are absent here. In addition, only one input of circuit portion III is coupled to the comparator means Comp. The construction of the embodiment shown in FIG. 2 corresponds to that of the embodiment shown in FIG. 1 in other respects, and corresponding components and circuit portions have been given the same reference symbols.
The operation of the circuit arrangement shown in FIG. 2 is as follows.
When the input terminals K1 and K2 are connected to a supply voltage source, the means I generate a high-frequency alternating current through the discharge lamp from a supply voltage delivered by this supply voltage source during stationary lamp operation. Before the stationary lamp operation phase, the circuit portion I generates an ignition voltage across the discharge lamp La during the ignition phase. A signal S generated by the means II is present at terminal Ts both during the ignition phase and during stationary lamp operation, signal S being a measure of the amplitude of the voltage across the discharge lamp La. The circuit portion III periodically changes the state of switching element Sw1 from a first to a second state and vice versa. Input terminal T is connected to the output of circuit portion A in the first state. Voltage V1 is present at the input terminal T. Input terminal T is connected to ground potential in the second state. Comparator Comp1 compares the internal signal S int generated by the circuit portion E with the internal reference signal generated by circuit portion C in both states. If the internal reference signal is exceeded in either state, the means III are activated via the output of comparator Comp1 and the input of circuit portion III. The means III change the operational state of the circuit portion I, for example by switching off circuit portion I.
The equations which are true for the embodiment shown in FIG. 2 are:
S1=x*V1/(x-1)
S2=V1/(x-1)
R=V1/(x-y)*I2
The ratio of the resistance values of ohmic resistors R1 and R2 is chosen such that the signal S at terminal Ts reaches the value S1 when the voltage across the discharge lamp reaches its maximum admissible value. Given this ratio of the resistance values of ohmic resistors R1 and R2, the signal at terminal Ts will reach the value S2 when the voltage across the discharge lamp La reaches its minimum admissible value. With the value R of ohmic resistor P as given by the equation, the internal reference value will correspond to the external reference value S1 with the integrated circuit in the first state and to the external reference value S2 with the integrated circuit in the second state. It is thus possible also in this embodiment to adjust the reference values S1 and S2 independently of one another to desired levels through a suitable choice of the resistance values of R1 and R2.
The embodiment shown in FIG. 3 utilizes, as does the embodiment shown in FIG. 2, only one internal reference value. The electrical quantity G in this embodiment is the current through the input terminal T, whose first value is I1 and whose second value is I2. I2 is chosen to be equal to zero here. The differences with the embodiment shown in FIG. 2 are that circuit portion A is replaced by circuit portion A' for generating a current with amplitude I1, and that circuit portion E is formed by a conductive connection between input terminal T and an input of comparator Comp1. The construction of the embodiment shown in FIG. 3 corresponds to that of the embodiment shown in FIG. 2 in other respects, and corresponding components and circuit portions have been given the same reference symbols.
The operation of the embodiment shown in FIG. 3 is as follows.
A signal S which is a measure of the voltage across the discharge lamp La is present at terminal Ts both during the ignition phase and during stationary lamp operation. The circuit portion III periodically changes the state of switching element Sw1 from a first to a second state and vice versa. In the first state, input terminal T is connected to the output of circuit portion A'. A current with amplitude I1 flows through the input terminal T. The current through the input terminal T is equal to zero in the second state. Comparator Comp1 compares the internal signal S int formed by the voltage at input terminal T with the internal reference signal generated by the circuit portion C in both states. If the internal reference signal is exceeded in either state, the means III are activated via the output of comparator Comp1 and the input of circuit portion III. The means III change the operational state of the circuit portion I, for example by switching off the circuit portion I. If the voltage at input terminal T is equal to the internal reference value V1 at the output of circuit portion C, it will be true for the embodiment shown in FIG. 3 that the voltage S1 at terminal Ts is:
S1=I1*(R)P+V1, (I)
in which (R)P is the resistance value of ohmic resistor P. This voltage S1 is the first reference voltage of the signal S. It is true in the second state that, if the voltage at input terminal T is equal to the internal reference value V1, the voltage S2 at terminal Ts is:
S2=I2*(R)P+V1. (II')
Since the amplitude of I2 was chosen to be zero, these equations may alternatively be written as:
S1=x*V1
S2=V1
R=(x-1)*V1/I1
The ratio of the resistance values of ohmic resistors R1 and R2 is chosen such that the signal S at terminal Ts reaches the value S1 when the voltage across the discharge lamp reaches its maximum admissible value. Given this ratio of the resistance values of ohmic resistors R1 and R2, the signal at terminal Ts will reach the value S2 when the voltage across the discharge lamp La reaches its minimum admissible value. The internal reference value corresponds to the external reference value S1 in the first state of the integrated circuit and to the external reference value S2 in the second state of the integrated circuit, provided that the value of ohmic resistor R is in accordance with the equation. It is thus possible also in this embodiment to adjust the reference values S1 and S2 independently of one another to desired levels through a suitable choice of the resistance values of R1 and R2.
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A circuit arrangement for supplying a discharge lamp comprises a control circuit which is provided with an integrated circuit. Means for generating a signal which is a measure of the lamp voltage are coupled to one pin of the integrated circuit. The periodic switching of the integrated circuit between a first and a second state insures that the lamp voltage will not exceed a minimum admissible value and a maximum admissible value. The use of only one pin makes the integrated circuit simple and accordingly inexpensive, while in addition only a small number of external components is required.
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TECHNICAL FIELD
[0001] The present disclosure relates generally to redox flow battery systems employing multicell stack reactors.
BACKGROUND
[0002] The so-called redox flow battery systems or briefly redox batteries, store energy in acid electrolyte solutions, namely a positive and a negative solution, that are flown through respective electrode compartments of the cells of a multicell electrochemical reactor during charge and discharge phases. The unlimited possibility of storing large volumes of positively and negatively charged electrolyte solutions containing ions of the so-called redox couple, make these systems exceptionally suitable for load-leveling (peak-shaving) in electric power generation and distribution industry, as storage battery in self standing wind farms or solar photovoltaic conversion plants as well as for powering vehicles. Most redox flow battery systems employ a multi-cell bipolar stack.
[0003] The redox couples used in a flow redox battery system are typically of multivalence metals dissolved in the two respective positive and negative electrolyte solutions, typically an acid electrolyte capable of dissolving the multivalence metal or metals in all states of oxidation. The above considerations are generally applicable to any multivalent metal providing a viable redox couple dissolved in an aqueous acid solution, wherein the redox couple metal ions sustain the anodic oxidation reaction and the cathodic reduction reaction the product of which remains dissolved in the acid electrolyte solution without undergoing any phase change, both during an electrochemical charging process as well as during an electrochemical discharge process. Vanadium, iron, chromium are the most commonly used metals to constitute usable redox couples in the positively charge electrolyte solution and in the negatively charged electrolyte solution.
[0004] Because of the many advantages recognized to a so called “all-vanadium” redox flow battery system, versus other known redox flow systems using redox couples of distinct metals in the positively charged and in the negatively charged electrolyte solutions, respectively, the ensuing description of exemplary embodiments will privileged reference to an all vanadium redox system. It should be clear that the considerations and advantages of the electrochemical plant architecture of the present disclosure remain applicable, mutatis mutandis to the use of other redox couples even of different metals.
[0005] A distinctive feature of flow redox battery systems is the, at least ideally, absence of gaseous substance evolution at the cell electrodes, during discharging as well as during charging processes.
[0006] However, as will be explained in this disclosure, unwanted hydrogen evolution may take place at certain conditions of operation of the cells, in view of the fact that cathodic hydrogen evolution is the favorite reaction in an acid environment and in order to contrast this thermodynamically favorite reaction at a cathodically polarized electrode, graphite or carbon electrodes are often used in redox flow cells because of the relative high hydrogen discharge over-voltage of carbon-base materials (often electrically conductive aggregates of carbon particles with a resin binder).
[0007] In order to enhance performance of relatively poorly conductive and poorly catalytic carbon electrode surfaces, the electrodes or more particularly the active electrode surface thereof is generally in form of a porous felt of carbon fibers readily permeated by the flowing electrolyte solution and back-contacted by the generally planar surface of a carbon-base bipolar electrical interconnecting septum (briefly “interconnect”) defining the respective flow compartment in cooperation with the opposing permionic membrane cell separator.
[0008] Carbon-base conductive plates pose fabrication limits to the maximum extension plate articles of graphite, glassy carbon or of aggregate of carbon particles and/or fibers may be economically fabricated and used in a form that must ensure acceptable mechanical sturdiness.
[0009] Another typical feature of redox flow cells is that the electrodes alternately switch back and forth from a cathodic polarization to an anodic polarization versus the respective electrolyte solution during discharging and charging phases of operation. This has practically excluded the possibility of using metal-base electrodes in the cells, because of their inability to withstand or perform in both conditions of polarization and has promoted the use of identical carbon-base electrodes in the respective flow compartments of the cells notwithstanding the many drawbacks that such an obliged choice entails.
[0010] For example, with a positively charged sulfuric acid electrolyte solution contaning the redox couple V[V]/V[IV], the positive electrode of the battery behaves as anode during a charging cycle extracting electrons from V[IV] in oxidizing vanadium to V[V] according to the reaction:
[0000] 2VO 2+ +H 2 O=2VO 2 + +2H + +e − E 0 Ox =1.00 Volt (1)
[0011] However, this is not the only reaction that may occur; a competitive reaction is the oxidation of water with the evolution of oxygen:
[0000] H 2 O=½O 2 +2H + +2 e − E 0 Ox =1.23 Volt (2)
[0012] The reason why the reaction (1) is the predominant reaction during charging is because the standard potential of reaction (1) is only 1 Volt while the standard potential of reaction (2) is higher and equal to 1.23 Volt. But these potentials are only the standard potentials, i.e. the voltage at which the reactions occur in standard conditions (25° C., at 1 Mole/liter, etc.). However, when the concentration of the reacting species decreases, the voltage will increase logarithmically according to the Nernst equation. Therefore, when during a charging cycle the concentration of the vanadile ions decreases, the corresponding voltage of the anodic reaction (1) will increase. At a high state of charge the split of the charging current between the two competitive anodic reactions will not longer favor the reaction (1) (i.e the desired V[IV] oxidation) but part of the electric current will support the parasite reaction (2). At very high state of charge, when almost all or all the V[IV]is oxidized to V[V], the only reaction that can and will occur will be the evolution of oxygen.
[0013] An attendant risk is that, when carbon or graphite electrode and/or distribution plates based on graphite are used, the oxygen evolved easily oxidizes the carbon degrading the felt electrode and even the current distributing back plate or intercell interconnect, through the following reaction:
[0000] 2H 2 O+C═CO 2 +4H + +4 e − (3)
[0014] In order to assure a long life of the positive electrode (felt and plates) based on carbon or graphite it is necessary to arrest the charging process upon reaching about 85%-to-90% of the maximum state of charge that maybe assumed by the positively charged electrolyte solution.
[0015] The use of carbon-base electrodes does not allow in practice a full charging of the positive electrolyte solution in consideration of the weakness of carbon based electrodes when anodically polarized versus the respective positive electrolyte solution when recharging the battery system. As oxidation of the multivalent ions in the positive electrolyte solution of the battery systems approaches the fully oxidized condition (100% charge), evolution of oxygen at the anode surface starts to be competitive toward the oxidation of the multivalent ions because of a reduced mass transfer across the electrode surface double layer (significant depletion). Moreover as discussed above, in these conditions, oxygen discharge may be practically “depolarized” by carbon through a combustion process with the nascent oxygen, which may rapidly destroy the carbon based electrode (often a carbon fiber felt) and may even degrade a carbon-base conductive intercell interconnect or current distributing/collecting back wall of the flow compartment of the cell.
[0016] Redox flow battery systems have an energy storage capacity strictly tied to the volumes of the two distinct positive and negative electrolyte solutions. This would ideally require the ability to fully charge the electrolyte solutions for maximizing energy storage per volumes of electrolyte solutions.
[0017] On another account, with a negatively charged sulfuric acid electrolyte solution contaning the redox couple V[III]N[IV], the negative electrode of the battery behaves as cathode during a charging cycle ceasing electrons to V[IV] reducing it to V[III]. Under certain conditions of operation parasitic hydrogen evolution may not be avoided at the negative electrode (cathode) of the cell. In particular, hydrogen evolution cannot be avoided when first conditioning a completely homogeneous system (first conditioning of the two electrolyte solutions). In fact, at start-up, the positive and negative tanks are filled with the same solution: practically containing 50% V[III] and 50% [IV]. The two solutions are then circulated through the corresponding compartments of the cells and an electric current forced through the cells disrupts the chemical homogeneity of the solutions oxidixing all the V[III] to V[IV] in the solution flown through the positive electrode compartment and reducing all the V(IV) to V[III] in the solution flown through the negative electrode compartment. At the negative electrode (cathode) the reaction being:
[0000] V 0 2+ +e − +2H + =V 3+ +H 2 O (4)
[0018] At the end of the conditioning period the negative electrolyte solution will contain only trivalent vanadium while the positive electrolyte solution will contains only tetravalent vanadium (vanadile).
[0019] During the conditioning process, hydrogen is evolved at the negative electrode as reported in 1 . 1 “Investigation of Hydrogen Evolution during the Preparation of Anolyte for a Vanadium Redox Flow Battery”, by X. Gao, M. J. Leahy and D. N. Buckley.
[0020] Of course, evolution of hydrogen according to: 2H + +e − =H 2 O is the only reaction that will occur when, at the end of a charging cycle of the functioning redox flow battery system, all the trivalent vanadium has been converted to bivalent vanadium.
[0021] Moreover, notwithstanding the use of carbon electrodes of relatively large hydrogen over-voltage for effectively under privileging cathodic hydrogen evolution that remains a thermodynamically privileged cathodic reaction in acid electrolytes, even during charging processes parasitic hydrogen evolution may also occurs, though at a very minoritary rate for various accidental reasons such as:
[0022] uneven distribution of electrolyte to the active electrode (cathode) surface causing local depletion of reagent species (trivalent vanadium);
[0023] excessively high current density at “hot spots” caused by uneven current distribution over the projected area of the electrode (cathode when charging);
[0024] presence of traces of metals having a low hydrogen overvoltage, such as Fe, Ni, Co, etc in the electrolyte. These metal deposit onto the negative electrode surface (cathode when charging) and catalyze hydrogen evolution.
[0025] When hydrogen is evolved, it must be released at the outlet of the respective compartment of each cell, to minimize disruption of uniformity of the current density because of uneven distribution of the electrolyte solution and formation of gas locks within the porous carbon felt cathodes.
[0026] Moreover, many applications would greatly benefit from the ability of reducing the time necessary to fully charge the battery system by being able to charge the electrolyte solutions at a greater current density then the “safe” maximum current density for more reliably ensuring the rated power output capabilities of the battery systems in delivering electrical energy to electrical loads of the system.
General Description of the Invention
[0027] These limitations and shortcomings are overcome and enhanced storage efficiency, reliability and durability of the redox flow system are achieved by employing distinct pluralities of cells wherein all the cells of a first plurality have porous metallic electrodes in both compartments through which respective electrolyte solutions flow during a charging process of the battery system and all cells of a second plurality may have porous carbon felt electrodes in both flow compartments through which the respective electrolyte solutions flow during a discharging process of the battery systems or solely in the compartment through which the negatively charged electrolyte solution flows and a porous metallic electrode in the other compartment where the positively charged electrolyte solution flows.
[0028] All the cells of the second plurality, destined to function during discharge of the flow redox energy storage system to power electrical loads, may have a common structure with carbon felt electrodes in both compartments and a intercell interconnect or electrode current distributor plate to the carbon felt electrodes made of a conductive aggregate of carbon particles or fibers and of a resin binder in both flow compartments of the cell.
[0029] Alternatively and preferably, an all carbon-based facing and an active porous carbon electrode may be retained only in the flow compartment of the “positively charged” electrolyte solution, at the surface of which ions of the redox couple in the flowing electrolyte solution undergo cathodic reduction, and a titanium base dimensionally stable anode of enhanced oxidizing activity of ions of the redox couple in the “negatively charged” electrolyte solution and at the surface of which ions of the redox couple in the flowing electrolyte solution undergo anodic oxidation.
[0030] Even more preferably, the permionic membranes used in all the cells of the second plurality (discharge cells), may have, over the surface in contact with the positively charged electrolyte solution (i.e. toward the substantially “all-metallic” flow compartment of the cell) a porous electro-catalytic facing layer of particles of an acid resistant and anodically stable metal black, typically a platinum black, bonded to the permionic membrane by hot pressing the highly catalytic particles mixed with a particulated non filming resin binder such as a polytetrafluoroethylene. According to this embodiment, the adhered porous layer constitutes an anode of much augmented specific active area capable of performing at a proportionately increased current density without excessive parasitic oxygen discharge and the pack of activated titanium micro-meshes will in practice function as current distributor to the active metal black particles layer bonded to the permionic membrane.
[0031] In any case, the intercell interconnect or electrode current distributor plate may have a titanium sheet facing in contact with the flowing “negatively charged” electrolyte solution for enhancing electrical conductivity through or along the electrically conductive septum and equipontentiality over the whole active projected area of the cell.
[0032] Differently, all the cells of the first plurality, destined to function for charging the redox flow battery system have metallic electrodes, for example of titanium, tantalum, zirconium (eventually coated with a layer containing a noble metal or a noble metal oxide, sub-oxides or mixed oxides), stainless steel, Hastelloys, titanium-palladium, titanium-nickel, lead, lead containing alloys, antimony, antimony containing alloys, all resistant to acid aqueous electrolyte solutions. The electrode in one flow compartment of the cells may include a n anodically passivating subtrate metal such as for example titanium, tantalum and alloys thereof, coated with an active surface layer that may contain, for example, ruthenium or iridium oxides mixed with titanium or tantalum oxides, over the surface of which the ions of the redox couple contained in the “spent” positively charged electrolyte solution undergo anodic oxidation, while the porous electrode in the other flow compartment of the cells may be of a metal or metal alloy having a relatively high hydrogen ion discharge overvoltage such as for example lead, antimony, lead-antimony alloys, stainless steel, titanium-palladium and titanium-nickel alloys, Hastelloys, optionally coated with a surface layer of lead and/or antimony, over the surface of which the ions of the redox couple contained in the “spent” negatively charged electrolyte solution undergo cathodic reduction.
[0033] Of course, the metallic electrodes must be resistant to the acidic electrolyte solutions, at the “free-acid” concentrations at which the redox system operates. In the case of an all-vanadium storage battery system, the metallic structural elements in contact with the electrolyte solutions must resist attack from the sulfuric acid solutions of vanadium.
[0034] Metallic electrodes have the advantage of alleviating the problem of efficient electronic current distribution or collection from the active surface sites of ion charge and ion discharge commonly posed by carbon felt electrodes. Metallic electrodes, even when compressively held in contact with a conductive back wall of the flow compartment or a conductive intercell interconnect ensure a far better electrical contact and may even be spot welded to it for minimizing contact resistances. Moreover, they have a much greater lateral conduction resistance (current paths in the electrode surface plane opposite to the counter electrode of the cell on the other side of the permionic membrane cell separator) than a carbon felt. Electrical cell resistance is thus significantly reduced and an enhanced equipotentiality over the whole active cell area is achieved, which also lessens risks of “hot spot” phenomena where locally the current density may inadvertently surpass design limit levels.
[0035] The metal electrodes should provide an active surface in contact by the electrolyte solution streaming through the typically shallow flow compartment without causing an excessive pressure drop in order not to burden power absorption by indispensable circulation pumps. Single or multiple micro wire nets or expanded thin metal sheets, eventually activated by an electro-catalytic coating as in the case of electrodes that are subject to function as anodes, having a base of an acid resistant metal and eventually also anodically passivable such as titanium, tantalum, and alloys thereof, stainless steel, Hastelloys, optionally undulated or deep-drawn at evenly distributed points or along uniformly spaced parallel lines in order to form spaced point rests pressing against the surface of the intercell interconnect, upon tightening the stack assembly, may be used in the cell compartments in lieu of a common compressible carbon felt electrode.
[0036] Alternatively, the multiple or single wire net or expanded thin metal sheet may be spot welded onto the surface of the intercell interconnect. Of course, instead of plastically deforming the micro wire nets or expanded thin metal sheets, the conductive back wall or intercell interconnect may have spaced ribs or evenly distributed protrusions of same height over the central active cell area thereof on the crests or tips of which, the active electrodes of micro wire net or expanded thin metal sheet may be pressed in contact or be spot welded.
[0037] The substantially all-metallic cells (charge cells) of the first plurality may have a projected active cell area (i.e. the projected area of the metallic electrodes and of the permionic membrane separator of the two flow compartments of the cell) smaller than the projected active cell area of the cells of the second plurality (discharge cells), to reduce costs of construction materials (electrodes and permionic membranes inventories) because of the elimination of the constraints on maximum affordable ionic current density imposed by the presence of carbon based electrodes.
[0038] Alternatively or coordinately with an eventual reduction of the active cell areas, the number of cells of the first plurality (charge cells) may be different and generally less than the number of cells of the second plurality (discharge cells).
[0039] Flow rates of the electrolyte solutions through the respective flow compartments of the cells of the first plurality (charge cells) may be regulated independently from the flow rates of the electrolyte solutions through the respective flow compartments of the cells of the second plurality (discharge cells), adding adaptability to the conditions of the respective processes of charging and discharging the energy storage system.
[0040] The two processes of charging and discharging the energy storage system may be conducted simultaneously, each under independently optimizable conditions to take advantage of concurrent renewable energy sources for charging the redox flow battery system while delivering electrical power to electrical loads.
[0041] According to a preferred embodiment, the cells of both distinct pluralities are bipolar cells electrically in series and part of the same stack assembly, though distinctly connected: the first plurality to a DC electrical source and the second plurality to a DC-to-AC conversion inverter.
[0042] According to an alternative embodiment, all the cells of both distinct pluralities are monopolar cells the electrodes of which are respectively connected according to a certain series-parallel scheme: those of the first plurality to a DC electrical source and those of the second plurality to a DC-to-AC conversion inverter.
[0043] The invention and important embodiments thereof are defined in the annexed claims, the recitation of which is intended to constitute part of the present specification and is here incorporated by express reference.
BRIEF DESCRIPTION OF THE DRAWINGS
[0044] FIG. 1 is a basic scheme of a flow redox battery system made according to the present disclosure.
[0045] FIG. 2 shows the basic scheme of FIG. 1 wherein the all metal electrode cells of a first plurality and all the cells of the second plurality are assembled in a unified stack assembly according to a preferred embodiment.
[0046] FIG. 3 replicates in part the scheme of the preceding figure schematically detailing the internal structure of stacked monopolar cells, according to a bipolar cell embodiment.
[0047] FIG. 4 reproduces in part the basic scheme of FIGS. 1 and 2 for detailing the inner cell structure according to a bipolar cell stack embodiment.
[0048] FIG. 5 is a simplified schematic exploded view of a unified stack of charge cells and discharge cells both of bipolar type.
[0049] FIG. 6 is a simplified schematic exploded view of a unified stack of charge cells and discharge cells both of monopolar type.
[0050] FIG. 7 is a “book-like” exploded view of stackable elements that define a bipolar charge cell.
[0051] FIG. 8 is a “book-like” exploded view of stackable elements that define a bipolar discharge cell.
DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0052] In principle, a flow redox battery system according to the present disclosure may have a functional scheme as the one depicted in FIG. 1 .
[0053] As illustrated in the scheme, all the cells of a first plurality A of cells destined to charge the two electrolyte solutions of the flow redox battery system are electrically connected to one or several DC electrical sources that may be in form of a solar panel array, a wind turbine or even a battery charger.
[0054] All the cells of a second plurality B of cells destined to deliver DC electrical power to an electrical load are electrically connected to the input of a common inverter that converts DC input power to AC electrical power, typically at the frequency and rated voltage of the public distribution grid.
[0055] Differently from the electrical connection lines, the hydraulic circuits of the two distinct electrolyte solutions are traced with solid lines. The positively charged electrolyte solution is stored in the respective electrolyte tank (+) and the negatively charged electrolyte solution is stored in the respective electrolyte tank (−).
[0056] The OCV device shown in FIGS. 1 to 4 is an optional monitoring implement of the state of charge of the redox flow battery system. It may be a single scaled down cell of same structure as the cells of the group A or B. The downsized replica cell permits to monitor the open circuit cell voltage, from which is possible to know the state of charge of the electrolyte solutions. In case of an all-vanadium redox flow battery system, an open circuit cell voltage of about 1.5V indicates a state of full charge of electrolyte solutions and an open circuit cell voltage of about 1.2V indicates that the electrolyte solutions are in a fully discharged condition.
[0057] In the exemplary scheme of FIG. 1 , both pluralities A and B of stacked cells, dedicated to the charging process and to the discharging process, respectively, have a bipolar stack architecture with serial flow of the two electrolyte solutions through the respective flow compartments of all the cells from one header h 1 to the other header h 2 of the stacked bipolar cells, whereby the two electrolyte solutions are generally fed in two distinct distribution chambers in one end header h 1 and collected into similar distinct chambers of the other end header h 2 . Internal ducting defines the distinct serial flow paths of the two electrolyte solutions. A circulation pump is used for each electrolyte solution.
[0058] FIG. 2 depicts an alternative embodiment of the same basic scheme of FIG. 1 , according to which all the cells are assembled in a unified bipolar cell stack.
[0059] In the exemplary embodiment shown, the two distinct pluralities A and B of cells destined to carry out the charging process and the discharging process of the battery system, respectively, the electrical end terminals of which are identified by the respective electrical connections to the possible types of DC power sources and to the input of a conversion inverter, are composed by three stacked sub-groups of serial flow bipolar cells A 1 , A 2 and A 3 .
[0060] Intermediate headers h i have four distinct electrolyte chambers providing for the exit of the two solutions flown serially through a sub-group of bipolar cells and for feeding the electrolyte solutions to the respective compartments of a first or inlet cell of the successive stacked sub-group of cells and so forth.
[0061] Subdivision of the plurality of cells destined to charge the flow redox battery system and of the second plurality of cells destined to deliver DC power towards the electrical loads, into sub-groups of cells (three sub-groups of cells in the depicted example), accomplishes the aim of incrementing the acceptable DC voltage generated by the particular DC electrical source that is exploited for charging the flow redox battery system and the DC voltage produced at the input of the DC-AC conversion inverter. At the same time, these increased DC input and output voltage capabilities of the multicell battery are made compliant with the attendant requirement of limiting the pressure drop (pumping losses) in flowing the two electrolyte solutions serially through tortuous inner ducting from a compartment of a cell to the correspondent compartment of the next cell. The parallel distribution of the circulating electrolyte solutions through a number of intermediate headers permits to limit the increment of overall pressure drop when augmenting the number of cells to function in serial (cascade) flow mode.
[0062] FIG. 3 replicates in part the basic scheme of FIGS. 1 and 2 for detailing the inner cell structure for a bipolar cell stack arrangement of the cells.
[0063] The basic inner cell structure is schematically depicted for only two groups of stacked bipolar cells, the group of cells on the left end side being used for charging the two electrolyte solutions by forcing a DC current through the sequence of bipolar cells of the group, exploiting the available DC voltage source.
[0064] The group of stacked bipolar cells on the right end side is used to deliver DC power to AC electrical loads through an inverter, by discharging the two electrolyte solutions.
[0065] The porous electrodes drawn with a light-dot hatching are preferably made of micro nets of an acid solution resistant and anodically stable base metal, like titanium or tantalum, activated by an electro-catalytic surface coating containing a noble metal or a noble metal oxide or mixed oxide. The porous electrodes drawn with dense line-hatching are also preferably metallic, of a metal or metal alloy having a relatively high hydrogen overvoltage, like lead or more preferably a lead-molybendum alloy in form of micro nets or wire mats. Alternatively, at least in the cells belonging to the group of cells that supply a DC voltage to the input of the inverter (discharge cells), the electrodes drawn with dense line-hatching may be of porous carbon felt.
[0066] The intercell interconnects I″ of both groups of bipolar stacked cells may be an electrically conductive aggregate of carbon and/or graphite particles and/or fibers with a resin binder or, more preferably, are made of a laminated sheet including at least a thin sheet of an acid resistant metal or metal alloy adapted to establish a good electrical contact with the porous electrodes, drawn with a light dot-hatching, of activated metallic micro nets or spot welded to them, and of a second thin sheet of a different metal or coating of acid resistant metal, having a suitably high hydrogen overvoltage, like for example a sheet or coating layer of lead, or of a lead-antimony alloy, adapted to establish a good electrical contact with the porous electrodes of relatively high hydrogen overvoltage, made for example of micro nets or wire mats of lead or lead-antimony alloys or of porous carbon felts or mats, drawn with a dense line-hatching.
[0067] The terminal current distributing septa I will have a surface in contact with the end electrodes of the groups of bipolar stacked cells, of appropriate electro-chemical characteristics and their structure is adapted to ensure a satisfactory equipotentiality and adapted to be electrically connected to the positive (+) and negative (−) rails of the respective DC buses for charging and discharging the redox flow battery system.
[0068] FIG. 4 replicates in part the basic scheme of FIGS. 1 and 2 for detailing the inner cell structure for a monopolar cell stack arrangement of the cells.
[0069] The basic inner cell structure is schematically depicted for only two groups of stacked cells, the group of cells on the left end side being used for charging the two electrolyte solutions by forcing a DC current through the sequence of bipolar cells of the group, exploiting the available DC voltage source.
[0070] The group of stacked monopolar cells on the right end side is used to deliver DC power to AC electrical loads through an inverter, by discharging the two electrolyte solutions.
[0071] The porous electrodes drawn with a light-dot hatching are preferably made of micro nets of an acid solution resistant and anodically stable base metal, like titanium or tantalum, activated by an electro-catalytic surface coating containing a noble metal or a noble metal oxide or mixed oxide. The porous electrodes drawn with dense line-hatching are also preferably metallic, of a metal or metal alloy having a relatively high hydrogen overvoltage, like lead or more preferably a lead-molybdenum alloy in form of micro nets or wire mats. Alternatively, at least in the cells belonging to the group of cells that supply a DC voltage to the input of the inverter (discharge cells), the electrodes drawn with dense line-hatching may be of porous carbon felt
[0072] The intercell interconnects I″ of both groups of monopolar stacked cells may all be of an electrically conductive aggregate of carbon and/or graphite particles and/or fibers with a resin binder or, more preferably, and differently from the case of the bipolar cell stack of FIG. 3 , may be of two different compositions, alternately assembled in the sequence of stacked monopolar cells.
[0073] The intercell interconnects I″ of both groups of monopolar stacked cells contacting the porous electrodes drawn with a light dot-hatching or spot welded to them, of activated metallic micro nets, over both sides, may be made with a sheet of an acid resistant metal or metal alloy adapted to establish a good electrical contact with the same type of electrodes (i.e. exposed to the same electrochemical agents and working conditions).
[0074] The intercell interconnects I″ of both groups of monopolar stacked. cells contacting the porous electrodes of relatively high hydrogen overvoltage (micro-nets or wire-mats of lead or lead-antimony alloys or porous carbon felts), drawn with dense line-hatching, may be made with a sheet of an acid resistant metal or metal alloy adapted to establish a good electrical contact with the same type of electrodes over both sides and having a suitably high hydrogen overvoltage, like for example a sheet of stainless steel or hastelloy, optionally coated with a layer of lead or of a lead-antimony alloy.
[0075] In case of monopolar cell stacks, the intercell interconnects I″ do not need to be septa of hydraulic separation and optionally they may have an open structure in a central area, coinciding with the projected area of the porous electrodes. For example, they may have a central area in form of an expanded sheet or with uniformly distributed close-spaced apertures or through holes, and a perimeter, essentially solid, seal surface. The open structure of intercell interconnects I″ will ensure equalization of hydraulic pressure in the same flow compartments of adjacently stacked cells, should it be desirable to relax manifolding design constraints.
[0076] The terminal current distributing septa I′ will have a surface in contact with the end electrodes of the groups of bipolar stacked cells, of appropriate electro-chemical characteristics (as the corresponding intercell interconnects) and their structure may be such to ensure a satisfactory equipotentiality and adapted to be electrically connected to the positive (+) and negative (−) rails of the respective DC buses for charging and discharging the redox flow battery system.
[0077] In the partial illustrations FIG. 3 and FIG. 4 of the repetitive arrangements of stacked elements constituting a sequence of bipolar and monopolar cells, respectively, can be clearly though schematically observed the flow compartments through which are flown the two electrolyte solutions, fed through respective inlet and outlet manifolds: inM 1 (+), outM 1 (+), inM 2 (−), outM 2 (−), in parallel to all the respective cell compartments, and the electrical connections of the conductive current distributing end interconnects I′ of stacked bipolar cells or alternately of all intercell interconnects I′ and I″ of stacked monopolar cells, to the positive (+) and negative (−) DC rails.
[0078] FIG. 5 is an exploded tridimensional view of a bipolar cell stack assembly for detailing an exemplary constitution of all metallic bipolar cell interconnects I″ and porous metallic base electrodes destined to be anodically polarized in the electrolyte solution flowing in contact therewith.
[0079] The laminated structure of the bipolar intercell interconnects I″, according to an all metallic embodiment of a stacked group of cells intended to function for charging or for discharging the redox battery system, is depicted in the exploded detail view of one bipolar intercell interconnect.
[0080] The depicted bipolar cell stack is a three-cell assembly, each cell including essentially a permionic membrane assembly M similar to the assembly of FIG. 3 of the cited prior PCT patent application similar to an embodiment described in the above cited prior PCT patent application No. PCT/IB2010/001651, of the same applicant. Each membrane assembly M is sandwiched between bipolar intercell interconnects I″ or equivalent terminal interconnects I′ at the end headers h 1 and h 2 . The signs of electrical connection terminals of the end interconnects I′ indicated in the figure are coherent to the connection of the bipolar cell stack to a DC voltage source for charging the electrolyte solutions of the redox flow battery system. However, a similar stacked group of bipolar cells may be used for charging the redox flow battery system, the signs of connection of the end interconnects of the stack would in this case be inverted.
[0081] As shown in the exploded view of one of the bipolar intercell interconnects I″, the core of the electrically conductive septum, according to a preferred embodiment, may be composed by two sheets of different metals m 1 and m 2 bonded together in electrical contact with each other. The sheet m 1 destined to be anodically polarized in the electrolyte solution flowing through the respective cell compartment may be of an anodically passivating, acid resistant metal; for example: titanium, tantalum or alloys thereof. The metal sheet m 2 destined to be cathodically polarized in the electrolyte solution flowing in the respective cell compartment may be of titanium, titanium-palladium or titanium nickel alloy, stainless steel, Hastelloy or other acid resistant metal, having a relatively high hydrogen ion discharge overvoltage or provided for this purpose with a surface coating layer of a high hydrogen overvoltage metal, preferably lead or lead-antimony alloy.
[0082] The bonding between the two metal sheets m 1 and m 2 may be established by any appropriate manner that shall ensure a good electrical contact. Conductive adhesive may be used or alternatively the two sheets of different metals may be soldered together by pressing them together with interposition of a low melting point solder, or even by spot welding the two sheets together.
[0083] The laminated metal septum has through holes for the constitution of inner inlet and outlet manifolds for the two distinct electrolyte solutions to be flown in the respective electrode compartments of each cell. As disclosed in said prior PCT patent application, insulating plastic grommets are introduced in the through holes of the laminated metallic core of the intercell bipolar interconnect I″ and the perimetral portions around the active electrode area, over both sides of the interconnect, are rendered electrically insulating by laminating thereon electrically insulating masks msk, for example of a thermoplastic insulating material resistant to the acid electrolytes, that will fuse with the plastic grommets inserted in the through holes to electrically shield planar perimeter surfaces over both sides of the interconnect as well as the surfaces of the circulation holes.
[0084] As disclosed in the cited prior PCT patent application of the same applicant, these masked perimeter areas of over both sides of the interconnect will coordinately bear against bas-relief patterned areas of the two elastomer gaskets assembled back-to-back that held there between perimeter portions of the permionic membrane M, thus defining distinct circulation paths and distribution channels in the respective compartments that allow to circulate the two electrolyte solutions in the respective compartments of all the cells of the bipolar stack.
[0085] The tridimensional view permits the observation of all the electrodes ma that will be anodically polarized in the electrolyte solution flowing though the respective compartment. Electrodes in contact with the unmasked conductive central area of the sheet m 1 of the laminated structure may be in form of a pack of three micro nets of titanium or tantalum, coated with a catalytic layer containing a noble metal (Pt, Ir, Ru, Pd) and/or oxides, sub-oxides or mixed oxides of at least a noble metal, for providing a large active surface of the porous metallic electrode structure, wetted by the flowing electrolyte solution permeating the pack of micro nets, in flowing through the electrode containing compartment, from an inlet port at one corner to exit an outlet port at the diagonally opposite corner of the flow compartment.
[0086] A similar stacked micro net pack or a porous wire pad of a high hydrogen overvoltage metal such as lead, lead antimony alloy is used on the other side (not visible in the figure) of the bipolar intercell interconnects, destined to be cathodically polarized in the electrolyte solution flowing in the respective cell compartment, and on the other side (not visible) of the end interconnect I′ associated to the header h 2 .
[0087] FIG. 6 is a tridimensional exploded view of two groups, A and B, of monopolar cells of a unified stack assembly according to a general arrangement of a multigroup stack of monopolar cells, as exemplified in FIG. 4 , according to which the cells of the first group A are used exclusively for charging the redox flow battery system and the cells of the other group B are used exclusively for supplying electrical loads by discharging the redox flow battery system.
[0088] According to this alternative embodiment, different laminated structures of interconnect may be used for the cells of the group A (charge cells) and for the cells of the group B (discharge cells). taking into account the fact that the monopolar stack organization requires that every interconnect I″ and I′, must have a cross sectional area (cross section of lateral conduction) dimensioned to ensure negligeable resistance (voltge drop) in order to provide a good equipotentiality and uniformity of current distribution over the whole projected area of the cell electrodes ma-mc and cfa-cfc in contact therewith, respectively.
[0089] In case of “all-metallic” charge cells (group A) and “all-carbon” discharge cells (group B) the interconnects of the “all-metallic” charge cells (group A) may have a single metallic sheet core m 3 of an acid resistant metal or alloy, adaptet to contact porous metallic anodes ma of porous metallic catodes mc over both sides and the interconnects of the “all-carbon” discharge cells (group B), adapted to contact carbon felt anodes cfa and carbon felt cathodes cfc over both sides, may be a laminated plate comprising a core sheet m 4 of highly conductive metal, for example stainless steel, titanium, Hastelloy, or even aluminum or copper, sandwiched between two sheets cl both of a conductive carbon-resin aggregate, bonded onto the metallic core by hot pressing or any other effective manner. The carbon lelt electrodes may be spot bonded to the carbon aggregate sheets using a conductive adhesive.
[0090] FIG. 7 is a “book-like” exploded view of stackable elements that define a bipolar charge cells and FIG. 8 is a “book-like” exploded view of stackable elements that define monopolar discharge cells.
[0091] The same reference numerical/literal identifiers that have been used in the preceding figures are used also in the two book like views thus allowing to observe, besides the organization of essential parts of the multicell stacks of this disclosure, also both types of porous electrodes: namely the electrodes that are exclusively polarized as anodes in the respective electrolyte solutions, ma or cfa, and the electrodes that are exclusively polarized as cathodes in the respective electrolyte solutions, mc or cfc.
[0092] Details of the membrane assemblies M and of the perimetral spacers 9 associated to them, as well as of the pairs of “bas-relief” patterned elastomer gaskets, back-to-back assembled for sandwiching there between the permionic membrane, of the shown embodiments are amply provided by the cited prior PCT patent application No. PCT/IB2010/001651, of the same applicant, the relevant content of which is here incorporated by express reference.
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Enhanced storage efficiency, reliability and durability of a redox flow battery system are achieved by employing distinct pluralities or groups of cells wherein all the cells of a first plurality have porous metallic electrodes in both compartments through which respective electrolyte solutions flow during a charging process of the battery system, and all cells of a second plurality may have porous carbon felt electrodes in both flow compartments through which the respective electrolyte solutions flow during a discharging process of the battery systems or solely in the compartment through which the negatively charged electrolyte solution flows and a porous metallic electrode in the other compartment where the positively charged electrolyte solution flows. All the cells of both groups of cells may be defined by repetitive sequences of stackable elements, according to a common bipolar or monopolar cell stack architecture.
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FIELD OF THE INVENTION
The present invention relates to the field of plant growth units.
BACKGROUND OF THE INVENTION
Plant growth units which attempt to conserve horizontal space and utilize vertical space, are known. A typical hydroponic plant growth system comprises a nutrient base and circulates a liquid nutrient through a cultivation portion wherein the plant seeds or young plants are anchored. For example, U.S. Pat. No. 5,502,923 discloses a hydroponic plant growth system which consists of a nutrient supply module base which supplies liquid nutrient to a series of vertically stacked prop modules, each prop module containing a number of plant growth sites. As liquid nutrient is pumped to each prop module, water is distributed to the plants grown therein.
U.S. Pat. No. 4,986,027 discloses a plant growth apparatus comprising a flexible tubular element wherein slits are provided for the growth of plants. A fluid nutrient is supplied to the root permeable material via a pump system, the fluid nutrient thereby being supplied to the plants.
Similarly, U.S. Pat. Nos. 5,440,836, 5,555,676, 5,918,416 and 4,033,072 all disclose vertical growing columns for growing a number of plants which are supplied water and nutrients through the use of nutrient solution pumps in the base of the respective apparatuses, which supply liquid nutrient to the top of the apparatuses. The liquid nutrient is supplied to the plants as the liquid travels from the top of the apparatuses to the bases.
Further, the prior art indicates that multiple vertical plant grow columns may utilize a single nutrient base. For example, U.S. Pat. No. 5,363,594 discloses a structure for a vertically oriented plant growth unit having a plurality of vertical columns arranged to conserve horizontal floor space and utilize a common base for the supply of liquid nutrient.
One of the potential limitations of the growth units described above is that the various plants of the growth units may receive different types and amounts of light from whatever light source is utilized. The differences in light quality and quantity may result in a divergence in growth and quality between plants grown at various levels and on various sides of the vertical columns.
U.S. Pat. No. 6,178,692 discloses a lighting system for use with one or more vertical growing columns. The lighting system is mobile and can apparently be angled to provide for equidistant lighting to the plants at both the top and the bottom of the vertical growth column. However, it would appear that equidistant lighting is to be provided by the lighting apparatus to a single side of each growth column. Each vertical column apparently has plants growing on all sides of the vertical unit and therefore a single lighting unit would appear only to provide equidistant lighting to those plants which are somewhat facing the lighting unit. To provide equidistant lighting to all plants on the growing columns, it would appear that two lighting units are set up on either side of one or more growing columns and angled to provide top to bottom equidistant lighting on each side of the vertical grow columns, thereby providing equidistant lighting to all plants. In at least some embodiments, this system therefore appears to be limited by the requirement for multiple lighting units to create equidistant lighting to all plants.
SUMMARY OF THE INVENTION
In one aspect, the present invention provides a plant growth unit including a nutrient supply module, one or more columns and a plurality of growth sites supported by the one or more columns. The nutrient supply module may be designed to contain a liquid nutrient. The one or more columns may be radially disposed about a central vertical longitudinal axis to define an internal space between the one or more columns. The internal space may be adapted to acconmmodate a light source. Each column may have an upper portion, a lower portion and a longitudinal passage through which the liquid nutrient may pass. Further, each column may be in fluid communication with the nutrient supply module for circulation of a liquid nutrient flow from the nutrient supply module to the upper portion of each of the one or more the columns and through the longitudinal passage to the respective lower portion of each of the one or more columns. The plurality of growth sites may be radially disposed about the longitudinal axis of the growth unit, generally facing the internal space, and each growth site may be positioned to contact the liquid nutrient flow.
In some embodiments, there are at least two columns and at least one growth site on each column. Such columns may be vertically oriented. In yet other embodiments, the growth unit has at least three columns, which may be circumferentially disposed in a generally circular pattern. In other embodiments, there is only one column which contains a plurality of growth sites. In such an embodiment, the single column defines its internal space by, for example, coiling around the longitudinal axis.
In accordance with some embodiments, two or more of the growth sites are approximately equidistant from the longitudinal axis. In other embodiments, at least two growth sites are located on each of the one or more columns and at least some of the growth sites on each column are vertically spaced apart. In such an embodiment, the growth sites at generally the same vertical level may be approximately equidistant from the longitudinal axis. In still other embodiments, the growth unit comprises at least two columns and at least two growth sites are located on each column. In such an embodiment, the growth sites on each column may be vertically spaced apart, and growth sites at generally the same vertical level may be approximately equidistant from the longitudinal axis.
The nutrient supply module may act as a base into which the columns are located, and may be shaped to facilitate balance of the system, such as disc shaped. The columns may be shaped to facilitate the nutrient flow from the upper portion of each of the columns to the lower portion of each of the columns, such as tubular columns.
The plant growth unit may further include one or more fluid connectors, such as tubes, which connect the nutrient supply module with the upper portion of each of the one or more columns. The fluid connectors may be designed to facilitate the liquid nutrient flow from the nutrient supply module to the tops of each of the one or more columns. The plant growth unit may also include a pump, or pumps, facilitating the liquid nutrient flow.
Where each column supports a plurality of growth sites, the growth sites may be longitudinally aligned. In some embodiments, the growth sites may protrude upwardly from the columns. The plant growth unit may also include a plurality of baskets which are designed to hold plants and designed to attach to the growth sites. The plants may be anchored to the growth unit by being placed inside the baskets, which are then attached to the growth sites.
Other embodiments of the present invention provide methods for growing plants in a growth unit. A nutrient supply module may be adapted for holding a liquid nutrient. One or more columns may be radially disposed about a central vertical longitudinal axis of the growth unit, thereby defining an internal space between the one or more columns. The columns may be disposed in fluid communication with the nutrient supply module and the internal space may be adapted to accommodate a light source. Each column may be designed with an upper portion, a lower portion and a longitudinal passage through which the liquid nutrient may pass. The nutrient supply module may be connected to the upper portion of the columns. A plurality of growth sites may be provided supported by the columns. The growth sites may be disposed radially about the longitudinal axis and generally facing the internal space. A plurality of plants may be then be located in the growth sites and the liquid nutrient may be added to the supply module. The liquid nutrient may then be circulated from the nutrient supply module to the upper portion of each of the one or more columns, through the longitudinal passage to the respective lower portion of each of the one or more columns. During its circulation, the liquid nutrient may be brought into contact with the plants.
In such a method, the introduction of a plurality of growth sites may further include locating at least two of growth sites equidistant from the longitudinal axis. During the introduction of a plurality of growth sites, at least two growth sites may be introduced on each of the one or more columns, at least some of such growth sites being vertically spaced apart on the columns. In such a method, the growth sites being at generally the same vertical level may be located approximately equidistant from the longitudinal axis. In another such method, at least two columns may be disposed and at least two growth sites may be introduced on each of the columns, such growth sites being vertically spaced apart on each column. In such a method, the growth sites which are at generally the same vertical level may be located approximately equidistant from the longitudinal axis.
While specific embodiments of the invention have been described and illustrated, such embodiments should be considered illustrative of the invention only, and not as limiting the invention to particular embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
In drawings which illustrate the embodiments of the invention,
FIG. 1 is an isometric view of a plant growth unit according to an embodiment of the invention
FIG. 2 is a longitudinal cross-sectional view of the plant growth unit of FIG. 1
FIG. 3 is an elevational side view of a plant growth unit, in an embodiment including two columns
FIG. 4 is a top view of the plant growth unit of FIG. 1
FIG. 5 is a bottom view of the plant growth unit of FIG. 1
FIG. 6 is a longitudinal broken away cross-sectional of a portion of the of the plant growth unit of FIG. 1
FIG. 7 is an elevational view of a plant growth unit, in an embodiment which includes a single column
DETAILED DESCRIPTION
Referring collectively to FIGS. 1, 2 and 4 through 6 , a plant growth unit according to one embodiment is shown. The plant growth unit includes a nutrient supply module 10 , a plurality of columns 20 , and a plurality of growth sites 30 supported by the columns 20 .
The nutrient supply module 10 is designed to contain a liquid nutrient 12 . In the embodiment shown, the nutrient supply module 10 acts as a base for the plant growth unit. The nutrient supply module 10 thereby stabilizes the plant growth unit and the columns 20 contained therein. However, the nutrient supply module need not act as a base for the growth unit which may be anchored or stabilized by alternative structures or supports.
The nutrient supply module 10 as shown in FIGS. 1 through 5 is disc shaped. However the nutrient supply module may take on various shapes adapted to enable it to act as a nutrient supply module in fluid communication with the columns 20 . Where the nutrient supply module 10 is intended to act as a base for the growth unit, it may be designed to maintain balance and support of the growth unit when placed on its intended surface.
The nutrient supply module 10 may have a hole in the upper portion of the nutrient supply module 10 located approximately at the longitudinal axis 40 , such a hole being adapted to hold a mesh basket for collecting medium and dead foliage to later be discarded, a allowing excess liquid nutrient 12 to pass into the nutrient supply module 10 . It is not necessary that the nutrient supply module 10 have such a hole. The outer portion of the upper surface of the nutrient supply module 10 may also slope downwardly towards the longitudinal axis 40 , allowing excess liquid nutrient 12 dripping from the columns 20 to drain towards the longitudinal axis 40 and the hole which may be present in the nutrient supply module 10 . The upper surface of the nutrient supply module 10 may also be level, or may slope in other directions.
The nutrient supply module 10 may be made of plastic, such as food grade polyethylene or food grade polycarbonate. The nutrient supply module 10 may be manufactured by, for example, placing food grade polyethylene powder in an aluminum mold, which is then heated and rotated on two separate axes. The food grade polyethylene in the mold melts as the mold is heated and the centripetal force of the rotation forces the melted plastic to the walls of the aluminum mold where it cools as the mold is removed from the heat. The nutrient supply module 10 is then removed from the mold. In alternative embodiments, the nutrient supply module 10 may be manufactured from a variety of other materials capable of containing the liquid nutrient 12 and allowing for fluid communication with the columns 20 .
In the illustrated embodiment of FIGS. 1, 2 , and 4 through 6 , the columns 20 are radially disposed about a central vertical longitudinal axis 40 and define an internal space 42 between the columns 20 . In the embodiments illustrated in FIGS. 1, 2 and 4 through 6 , four columns 20 are disposed approximately equidistant from the longitudinal axis 40 and approximately equidistant from each other, as shown in FIG. 4 . Any number of columns 20 may be arranged about the longitudinal axis 40 . For example, as shown in FIG. 3, two columns 20 may be radially disposed about the longitudinal axis opposite each other. The columns 20 may be equidistant from the longitudinal axis 40 and equidistant from each other. Where there are at least three columns, the columns may be circumferentially disposed in a generally circular pattern. In alternative embodiments, the columns 20 need not be equidistant from the longitudinal axis 40 or each other, while the columns 20 remain radially disposed about the longitudinal axis 40 and define an internal space 42 .
The columns 20 are generally vertically oriented and generally straight in the embodiments shown in FIGS. 1 through 6. In alternative embodiments, it is not necessary that the columns be vertically oriented and/or straight. The columns may be angled in any direction, and at any degree. For example, the columns may be tilted towards or away from the longitudinal axis 40 . The columns may also be of various appropriate curvatures or shapes. Appropriate curvatures and shapes of the columns may be selected so as to maintain the other functional objectives of the various embodiments of the invention.
The internal space 42 may be adapted to accommodate a light source. The light source may be, for example, a tubular light source which can be supported, for example by hanging, vertically between the columns 20 in the internal space 42 . In some embodiments, for generally equidistant lighting and advantageous conditions for all plants growing in the growth unit, the tubular light source may be supported approximately along the longitudinal axis. Alternatively, as shown in the alternative embodiment of FIG. 3, the light source could be a series of bulbs 44 supported vertically between the columns 20 in the internal space 42 , in some embodiments the series of bulbs 44 being aligned approximately along the longitudinal axis for generally equidistant lighting. A series of bulbs 44 may, for example, be vertically supported hung by a chain 46 , or other support, from, for example, a support beam 48 . The light source could also, for example, be a bulb hung in the internal space, or supported in the internal space by the base along the longitudinal axis. Appropriate bulbs for use as a light source include 400 watt Metal Halide, 400 watt High Pressure Sodium, 250 watt Metal Halide, 250 watt High Pressure Sodium and 430 watt Son Agro. Larger bulbs, such as 600 watt High Pressure Sodium, 1000 watt High Pressure Sodium or 1000 watt Metal Halide, may also be used; however, when larger bulbs such as these are used as a light source for the plant growth unit, they may have to be continuously moved up and down the longitudinal axis when lit.
Each column 20 may have an upper portion 22 , a lower portion 24 and a longitudinal passage 26 through which the liquid nutrient 12 may pass. The columns 20 may be tubular, thereby defining the longitudinal passage 26 . The columns 20 may be made of plastic or another suitable material, such as clay, metal or wood. The columns 20 may, for example, be manufactured by way of known injection mold techniques, or extruding plastic techniques. Alternatively, the columns 20 could be manufactured from pre-existing ABS or PVC elbows, Tee's and straight lengths, which can be glued together. Metal elbows, Tee's and straight pipes could be welded together to form the columns 20 . The columns 20 could alternatively be carved from wood, or other carvable material, or could be formed by gluing or nailing wooden planks together to form square columns. A column may also be formed from clay by shaping clay pieces and then mounting the clay pieces into a column.
The columns 20 , in the embodiments shown, rest on the bottom of the nutrient supply module 10 and have a hole in the column such that the liquid nutrient flow 14 may pass out of the lower potion 24 of the columns 20 . In alternative embodiments, the columns 20 may be supported above the bottom of the nutrient supply module and the liquid nutrient flow 14 may pass out of the bottom of the columns 20 .
In some embodiments, the longitudinal passage 26 may be hollow or may contain a permeable material, such as a planting medium, through which the liquid nutrient 12 is able to pass. Suitable planting medium includes, but is not limited to, Hydroton™ (or other small round, kiln heated clay types), Sunshine Mix™ (or other peat perlite soil like mixes), perlite, vermiculite, rockwool, washed rock, sand, foam or animal castings. The permeable material is also not limited to planting medium. It may be possible to use a wide range of material which allows for the passage of the liquid nutrient 12 through the longitudinal passage 26 , while still allowing the growth unit to meet the other finctional objectives of various embodiments of the invention.
Each column 20 may be in fluid communication with the nutrient supply module 12 for circulation of a liquid nutrient flow 14 . In the embodiments shown in FIGS. 1 through 6, a plurality of pumps 16 circulate the liquid nutrient 12 from the nutrient supply module 10 through a plurality of tubes 18 to the upper portion 22 of each of the columns 20 and through the longitudinal passage 26 to the respective lower portion 24 of each of the columns 20 . In alternative embodiments, a single pump may facilitate the liquid nutrient flow 14 . In some embodiments, once the liquid nutrient is pumped to the end of the tubes 18 at the upper portion 22 of each of the columns 20 , the liquid nutrient is allowed to cascade down the longitudinal passage and back into the nutrient supply module 10 via gravitational pull. The pumps 16 may be, for example, Little Giant™ sump pump 1200 gph, or other such pumps manufactured by Magdrive™ and Rio™. The tubes 18 may be, for example, ½ inch commercial garden hose, ½ inch rubber garden hose, ½ inch ABS hose or other size hoses of the same type. The system connecting the tubes 18 to the columns 20 and the pump(s) 16 may incorporate ABS elbows, ABS stop plugs, hose clamps, rubber washers, ½ inch ABS tees, ½ inch shut off values and female to male hose adaptors, arranged to facilitate the liquid nutrient flow 14 . Other types of fluid connectors are also contemplated by the present invention.
Alternative means for establishing the liquid nutrient flow 14 are also contemplated. For example, a pump may be located near the upper portion 22 of the columns 20 to pull the liquid nutrient 12 from the nutrient supply module 10 . The tubes 18 do not have to be inside the columns 20 , but may connect the nutrient supply module 10 to the upper portion 22 of each of the columns 20 on the outside of the columns 20 . The present invention contemplates such other means for establishing the liquid nutrient flow.
In the embodiments illustrated, a plurality of growth sites 30 are located on each column 20 , such growth sites 30 being radially disposed about the longitudinal axis 40 and generally equidistant from the longitudinal axis 40 . As illustrated, the growth sites 30 generally face towards the internal space 42 . This provides generally equidistant lighting in the embodiment shown to all plants in the growth unit when a tubular light source is vertically supported along the longitudinal axis 40 .
There may be one or more growth sites 30 on each column 20 . Where there is more than one growth site 30 on each column 20 , the growth sites 30 may be vertically spaced apart on the columns 20 .
The growth sites 30 may be equidistant from the longitudinal axis 40 for equidistant lighting, even where the columns 20 themselves are not equidistant from the longitudinal axis 40 . However, in some embodiments the present invention also contemplates a growth unit where the growth sites are not equidistant from the longitudinal axis 40 .
Where at least some of the growth sites 30 are vertically spaced apart on the columns 20 , those growth sites 30 which are at generally the same vertical level may be equidistant from the longitudinal axis. This may provide advantageous lighting conditions to all the plants where, for example, a single bulb, located along the longitudinal axis, is used as a lighting source. In such a growth unit, the growth sites vertically further away from the bulb may be situated closer to the longitudinal axis than those growth sites vertically closer to the bulb, in order that all plants receive equidistant lighting for advantageous conditions. Those growth sites at the same vertical level may therefore be equidistant from the longitudinal axis, when even where not all growth sites in the growth unit are equidistant from the longitudinal axis. A variation in the distance of the growth sites from the longitudinal axis may be accomplished by tilting the columns or designing the columns to vary in distance from the longitudinal axis. Alternatively, the growth sites may protrude from the columns at different lengths, varying the distance of the growth sites at different vertical levels to the longitudinal axis.
The growth sites 30 in the embodiments illustrated in FIGS. 1 through 6 protrude upwardly from the columns 20 in order to facilitate anchoring plants at the growth sites 30 . The growth sites 30 in the embodiments illustrated angle upwardly at approximately a forty-five degree angle. The growth sites 30 may protrude from the columns 20 at alternative angles, however the angle will preferably be chosen as one appropriate to maintain plants in growth sites. The present invention also contemplates a growth unit where the growth sites 30 do not protrude from the columns 20 .
In the embodiments shown in FIGS. 1 through 6, the growth sites 30 form a unitary part of the columns 20 , the entire structure being formed from plastic or another suitable material. The invention also contemplates a growth unit where the growth sites 30 are not formed as a part of the columns 20 , but are later attached to the growth unit as separate components.
The growth sites 30 shown in the illustrations have circular openings 32 into which plants may be anchored and grown. The present invention is not limited to growth sites which have circular openings for receiving the plants. The growth sites may take various forms which would allow for a plant to be grown. For example, the various shapes and sizes of planting pots as normally found in the field of gardening may be used as growth sites, the size being limited of course by the size of the growth unit. Accordingly, a wide variety of types of growth sites that could be used in growth units are contemplated by this invention.
In the embodiments shown in FIGS. 1 through 6, the growth unit includes baskets 34 which fit into the circular openings 32 of the growth sites 30 . As shown in FIG. 6, the baskets 34 may be designed to hold plants 36 . The baskets 34 may be made of plastic or another suitable material. In the embodiment shown, the baskets 34 are open weave baskets. The plants 36 sit in the baskets 34 and the plant roots 38 protrude through the bottom of the baskets 34 . The present invention also contemplates other means for retaining the plants in the growth sites. For example, the columns 20 may contain a planting medium in the longitudinal passage 26 into which the plants may be anchored and grown.
Each growth site 30 may be positioned to contact the liquid nutrient flow 14 . The plants 36 may be located in the baskets 34 , which are placed in the growth sites 30 , and the plant roots 38 protrude from the base of the baskets 34 , as illustrated in FIG. 6 . The plant roots 38 are therefore located within the longitudinal passage 26 of the column 20 . As the liquid nutrient flow 14 is established through the longitudinal passage 26 , the liquid nutrient flow 14 will come into contact with the plant roots 38 .
There are other means for positioning the various types of growth sites such that the plant roots will come into contact with the liquid nutrient flow as it passes through the longitudinal passage of the columns. For example, where the longitudinal passage contains planting medium into which the plants are anchored at the growth sites, the roots of the plants will come into contact with the liquid nutrient flow as it travels through the planting medium.
Various types of liquid nutrient 12 may be used. The liquid nutrient may contain essential elements needed for plant growth, such as Nitrogen, Phosphorus, Calcium, magnesium, Sulphur, Iron, Potassium, Boron, Manganese, Zinc, Copper, and Molybdenum. For example, GGold Nutrient Line™ or General Hydroponics Flora Line™ contain these essential elements needed for plant growth and therefore may be used as the liquid nutirent. The quality, quantity and type of liquid nutrient used will vary depending on many factors, such as the type and age of the plants being grown. The liquid nutrient should be chosen with a view to establishing advantageous growth conditions.
Referring to FIG. 7, a plant growth unit according to an alternative embodiment of the invention is shown. The plant growth unit includes a nutrient supply module 50 , a single column 60 and a plurality of growth sites 70 supported by the column 60 . As described above, the nutrient supply module 50 is designed to contain a liquid nutrient 52 and, as in the embodiment shown, may act as a base for the growth unit. The nutrient supply module 50 may take on various shapes and various modes of manufacture, as outlined above.
As shown in FIG. 7, the single column 60 is disposed radially about a central vertical longitudinal axis 80 and defines an internal space 82 . This may be accomplished by wrapping the column 60 around the longitudinal axis. In the embodiment illustrated, the column 60 forms a uniform helical structure. The column 60 may, at all points, be generally equidistant from the longitudinal axis 80 . However, the present invention contemplates many various forms that the column 60 may take in order to dispose itself radially about the central longitudinal axis 80 and define an internal space 82 . The column 60 need not vertically rise in a uniform manner and all portions of the column 60 need not be equidistant from the longitudinal axis 80 .
The internal space 82 in FIG. 7, as with the previously described embodiments, may be adapted to accommodate a light source. A variety of light sources may be used, as described above.
The column 60 may have an upper portion 62 , a lower portion 64 and a longitudinal passage 66 through which the liquid nutrient may pass. As described above, the column 60 may be made of a variety of materials and constructed in a variety of ways. Further, as also described above, the longitudinal passage 66 may be empty or contain a permeable material through which the liquid nutrient 52 may pass.
The column 60 may be in fluid communication with the nutrient supply module 50 for circulation of a liquid nutrient flow 54 . In the embodiment shown in FIG. 7, a pump 56 circulates the liquid nutrient from the nutrient supply module 50 through a tube 58 to the upper portion 62 of the column 60 and through the longitudinal passage 66 to the lower portion 64 of the column 60 . As described above, various pumps 56 and tubes 58 are contemplated, as are other methods of establishing the liquid nutrient flow 54 .
In an embodiment of the invention including a single column 60 , a plurality of growth sites 70 may be located on the column 60 . The growth sites 70 are radially disposed about the longitudinal axis 80 and the growth sites 70 generally face towards the internal space 82 . In the embodiment shown, the growth sites 70 are located equidistant from the longitudinal axis 80 , resulting in equidistant lighting to all plants in the growth unit when a vertical light source is supported along the longitudinal axis 80 . Though the growth sites 70 may be equidistant from the longitudinal axis 80 , as described above, the growth sites need not be equidistant from the longitudinal axis. In alternative embodiments, only those growth sites at generally the same vertical level may be equidistant from the longitudinal axis.
As also discussed above, in embodiments such as illustrated in FIG. 7, the growth sites 70 may or may not protrude from the column 60 , and may do so at various distances and angles. The growth sites 70 may be of various shapes and sizes, and the growth unit may use various means for anchoring the plants in the growth sites 70 . The growth sites 70 may be positioned to contact the liquid nutrient flow 54 in the various ways described above and there are various options for the liquid nutrient to be used.
The present invention also contemplates a method for growing plants where a plant growth unit as described above is provided, plants are planted into the growth sites and a liquid nutrient flow is established.
While specific embodiments of the invention have been described and illustrated, such embodiments should be considered illustrative of the invention only and not as limiting the invention as construed in accordance with the accompanying claims.
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The present invention relates to the field of plant growth units, and more particularly pertains to an apparatus for plant cultivation which conserves horizontal space and utilizes vertical space, while providing for the growth of plants which are cultivated in an indoor environment. The plant growth unit comprises a nutrient supply module and one or more columns radially disposed about a central vertical longitudinal axis thereby defining an internal space between the one or more columns designed to accommodate a light source. Each column is in fluid communication with the nutrient supply module for circulation of a liquid nutrient flow. The one or more columns support a plurality of growth sites, which are radially disposed about the longitudinal axis and generally face the internal space. Each growth site is positioned to contact the liquid nutrient flow.
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BACKGROUND OF THE INVENTION
The present invention relates to an inserting carrier for looms with removal of the filling yarn from stationary bobbins, having a filling yarn clamping device and a warp yarn divider piece developed on the top of the rear side wall of the carrier facing away from the tip of the shed, the upper edge of which divider piece is developed as an ascending first yarn guide curve and then passes into an open yarn groove which is covered by a horn which extends out in the direction away from the tip of the shed.
In one known inserting carrier, the filling yarn clamping device, which consists of a fixed jaw and a movable jaw pressed resiliently against the fixed jaw, is mounted on the front side wall of the carrier. The filling yarn tensioned between the yarn groove and the clamping device thus extends within the carrier in a plane lying approximately parallel to the central plane of the warp yarn. This horizontal filling yarn guide in the inserting carrier is disadvantageous particularly in the case of looms in which a flexible band is used as drive means for the carrier, since it is very difficult to hold the extending carrier so stable in the direction perpendicular to the central plane of the warp yarn that it can reliably grasp the offered filling yarn in the center of the shed.
In the case of another known inserting carrier, this disadvantage is avoided in the manner that the filling yarn clamping device is formed of a spring loaded clamping tongue which is swingable perpendicular to the central plane of the warp yarn and supported on the bottom surface of the inserting carrier. In the case of this inserting carrier, the yarn groove is arranged in the cover surface of the carrier and the filling yarn is thus guided in vertical direction in the inserting carrier. Actual practice has shown that a vertically guided filling yarn is grasped with much greater assurance by the extending carrier than a horizontally guided yarn. The arrangement of the yarn groove on the cover surface of the carrier leads however to the result that this inserting carrier has a warp divider piece not only at the head of its rear side wall but also at the head of its front side wall, the latter warp divider piece furthermore also protruding farther forward than the divider piece on the rear side wall. The warp divider piece on the front side wall increases the danger of loose warp yarns possibly catching in the inserting carrier and/or of the warp yarns being torn by it. An additional disadvantage is that no means are provided in connection with this known inserting carrier to prevent the feeding of possible loose warp yarns into the yarn groove and to the clamping tongue.
The closest prior art known to the applicants in connection with this application is the U.S. Pat. No. 3,638,686.
SUMMARY OF THE INVENTION
The present invention avoids the aforesaid disadvantages and it is characterized by the fact that the filling yarn clamping device is formed by a spring-loaded clamping tongue which is swingable perpendicular to the central plane of the warp yarn and supported on the bottom surface of the carrier, that a second yarn guide curve extending from the rear side wall of the carrier towards the front side wall adjoins the first yarn guide curve, and that a third yarn guide curve leading from the horn up to the clamping slot of the clamping tongue is provided.
The inserting carrier in accordance with the invention has only one warp divider piece, although the filling yarn is guided vertically in the carrier. This advantageous feature of the inserting carrier is obtained by the special shape and the cooperation of the second and third yarn guide curves.
Brief Description of the Drawings
These and other objects of the invention will be explained in further detail below on the basis of an illustrative embodiment and the drawings, in which:
FIG. 1 is a top view of an inserting carrier;
FIG. 2 is a view in elevation seen in the direction of the arrow II of FIG. 1;
FIG. 3 is a sectional view taken along the line III--III of FIG. 1;
FIG. 4 is a sectional view taken along the line IV--IV of FIG. 2; and
FIG. 5 is an enlarged sectional view taken along the line V--V of FIG. 2;
FIG. 6 is a bottom view seen in the direction of arrow VI of FIG. 2; and
FIG. 7 is a perspective view of the inserting carrier cast in a single piece.
DESCRIPTION OF THE PREFERRED EMBODIMENT
An inserting carrier 1 as shown in the figures has a base 3 of approximately U-shaped cross section which is firmly connected to a flexible steel band 2 which serves as the drive for inserting and removing the carrier from the shed of the loom. The base 3 has a front side wall 4 facing the point of the shed formed in operation by the warp yarns K whose central plane is designated M; a rear side wall 5; a cover surface 6; and a clamping tongue 8 which is supported in the region of the bottom 7 of the inserting carrier 1. The two side walls 4 and 5, the cover surface 6, and the carrier bottom 7 together with the clamping tongue 8 form a tunnel-shaped hollow space for the entrance of an extending carrier (not shown).
The shell of the hollow space, defined by the side surfaces 4 and 5, the cover surface 6 and the carrier bottom 7, is formed of two structural parts 38 and 39 of substantially U-shaped profile which are screwed together, the part 38 being open towards the top and the part 39 being open towards the bottom.
The part 38 is attached to the base 3 and forms the carrier bottom 7 and the greatest part of the front side wall 4. The structural part 38 is furthermore bent 90° on the upper edge of the front side wall 4 in the direction towards the rear side wall 5 and thus also forms a part of the cover surface 6.
The structural part 39 which adjoins the part 38 in the direction toward the point of the carrier forms the rear side wall 5, the greatest part of the cover surface 6, and a small part of the front side wall 4. The contact edge extending between the two structural parts is designated 26 in the cover surface 6, and 27 in the front side wall 4. The rear side wall 5 is attached by a screw to the base 3 and by two screws 22 to the carrier bottom 7. In the region of the front side wall 4, the structural parts 38 and 39 are screwed together by a screw 25.
The carrier bottom 7 consists of two side strips 9 and 10 which are connected at their front end to a first cross arm 11 and at their rear end to a second cross arm 11'. A forward extending narrow tip 12 is attached to the cross arm 11. The clamping tongue 8 formed by a leaf spring is connected at its rear end by two screws 13 (FIG. 5) to the base 3 and extends in the longitudinal direction of the carrier 1 through a cutout 14 in the carrier bottom 7 formed between the side strips 9 and 10 and the cross arm 11. The cross arm 11 is provided on its bottom with a U-shaped guide groove 15 with stepped side walls 16 and 17. The side walls 16 and 17 are so developed that the width of the groove 15 decreases in wedge shape from the bottom to the top. The clamping tongue 8 which is guided in the stepped portion of the groove 15 is provided in this region of guidance with a trapezoidal cross-section with side edges which taper from the bottom to the top so that a wedge surface guide is present between the clamping tongue 8 and the groove 15.
The portion of the side edge of the clamping tongue 8 facing the point F of the shed serves as guide and abutment for the clamping tongue. The portion of the side edge of the clamping tongue 8 facing away from the point F of the shed which rests against the stepped side wall 17 of the groove 15, together with the side wall 17 and with the edge of the tip 12 of the cross arm 11 adjoining same in the direction towards the tip 18 of the clamping tongue 8 forms the clamping slot 40 for a filling yarn S which is to be grasped. Since the clamping tongue 8 tapers to the point 18 at its front end, the clamping slot 40 widens in wedge shape in forward direction away from the cross arm 11 and thus forms an entrance funnel for the filling yarn S. The side edge of the clamping tongue 8, which also serves to form the clamping slot, may in this connection lead away from the cross arm 11 to the point 18 in a continuous curve or in successive curves of an inclination which increases toward the tip 18.
At its longitudinal edge facing the point F of the shed the clamping tongue 8 has an extension piece 19 which is bent 90° upward from the clamping tongue and then 90° forward towards the tip F of the shed, said extension piece extending into a T-shaped recess 20 in the front side wall 4. The leaf spring which forms the clamping tongue 8 is imparted such an initial stress that in its condition of rest it presses from below against the cross arm 11. The clamping tongue 8 can be swung downward by downward acting force on the attachment piece 19, the lower edge of the transverse arm of the recess 20 serving to limit the amplitude of swing.
The rear side wall 5 is developed at its tip 23 as a warp divider piece. The upper edge of the tip 23 forms an ascending first yarn guide curve 24. Adjoining the first yarn guide curve, an open yarn guide groove 28 is recessed in the rear side wall 5, said groove having a straight portion and a portion which descends obliquely downward. The yarn guide groove 28 is covered on top by a horn 29 attached to the cover surface 6 which is staggered with respect to the warp divider piece and extends out in the direction away from the point F of the shed, so that loose warp yarns cannot enter into the yarn guide groove 28.
On the rear side wall 5, within the region of the linear portion of the yarn guide groove 28 a horizontally extending deflection element 31 extending towards the shed point F is fastened by screws 30. The cover surface of the deflection element 31 lies at the level of the lower edge of the straight portion of the yarn guide groove 28. The edge of the deflection element 31 which leads away from the groove 28 is developed as a second yarn guide curve 32. The deflection element 31 is attached at its rear end by a screw 33 and a washer 34 to the cover surface 6. The deflection element 31 also bears an upward extending stop pin 35.
The edge 36 of the cover surface 6 which adjoins the horn 29 extends obliquely to the base 3 to the front side wall 4 and passes into the rounded edge 37 of the front side wall 4. The edge 36 and the edge 37 serve as a third yarn guide curve which leads in a continuous path to the clamping slot from the horn 29 and thus from the upper edge of the yarn guide groove 28.
The manner of operation of the inserting carrier described is as follows: When the inserting carrier 1 is moved by the band 2 out of its position of rest in the direction towards the shed, the first yarn guide curve 24 comes against the filling yarn S, which is guided from the selvage on the insertion side approxinately horizontally to a member 41 of a yarn transfer device. The tensioned filling yarn S slides into the yarn guide groove 28, it being strained between the second and third yarn guide curves 32 and 36, 37. The filling yarn S passes from the second yarn guide curve 32 to the longitudinal edge of the deflection element 31 facing the web point F of the shed and slides up to the stop pin 35. From the third yarn guide curve 36, 37 the filling yarn S passes directly into the clamping slot 40 up to a position corresponding to its thickness, and is clamped fast there. Thereupon, the filling yarn S is cut off between the insertion-side selvage and the clamping slot and the actual insertion of the filling now commences up approximately into the center of the shed where the filling yarn is now taken over in known manner, by an extending carrier. The portion of the filling yarn S offered the extending carrier extends in the inserting carrier 1 from the clamping slot 40 to the longitudinal edge of the deflection element 31 facing the shed tip F and is therefore approximately perpendicular to the warp central plane M. Upon the moving of the empty inserting carrier 1 out of the shed, the clamping tongue extension piece 19 comes against an actuating element, as a result of which the clamping tongue 8 is swung downwards so as to clean dirt off from the clamping slot.
The inserting carrier 1 described, of course, need not consist of the two structural parts 38 and 39 which are screwed together but may, for reasons of rational manufacture and design, be cast in a single piece. In such case, the screws 21, 22, and 25 as well as the contact edges 26 and 27 between the two structural parts 38 and 39 would be eliminated. The extension piece 19 of the clamping tongue 8 need not extend into the T-shape recess 20 of the front side wall 4 but can lie in front of the front side wall 4 so that the recess 20 is unnecessary.
It will be appreciated that various changes and/or modifications may be made within the skill of the art without departing from the spirit and scope of the invention illustrated, described, and claimed herein.
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An inserting carrier for looms with removal of a filling yarn from stationary bobbins having a filling yarn clamping tongue which is swingable perpendicular to a central plane of the warp yarn and supported on the bottom surface of the carrier.
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This application is a division of application No. 09/244,983 filed Feb. 4, 1999, now U.S. Pat. No. 6,237,295.
FIELD OF THE INVENTION
The present invention is directed to a flooring assembly and fastener therefor and, in particular, to recycled plastic lumber decking and unitary clips to retain the decking in a stable and level manner on a plurality of horizontal joists.
BACKGROUND OF THE INVENTION
The present invention relates to an innovative flooring assembly and method, as well as several embodiments of a unitary fastener clip used to secure the flooring assembly to a plurality of horizontal support members, such as joists, so as to construct a platform, patio or a raised deck. This flooring assembly and fastener clip find particular utility by providing homeowners and building contractors with a relatively simple, secure and reliable means to construct a platform or a deck with a minimum number of component parts, and without specialized tools or expertise. The preferred embodiment of the flooring assembly employs recycled plastic lumber as the flooring component, which promotes the conservation of resources and the environment.
In the prior art, various fasteners have been proposed to retain flooring or decking in place, none of which approach the simplicity, economy and ease of use of the present invention. For instance, U.S. Pat. No. 5,660,016 to Erwin et al. discloses a foam-filled extruded decking plank and decking attachment system. This system includes clamps to hold down blocks which are secured onto a structure that supports the planks. The blocks permit relative motion between the planks. U.S. Pat. No. 4,599,842 to Counihan discloses a fastening system for fastening planar sections such as flooring boards to a base surface. The system includes fastening strips that interlockingly engage in a set of grooves cut in the ends of the boards. While the system of Erwin et al. recognizes that joist and decking fabricated from different construction materials may expand or contract at differing rates, this system is rather complex and especially adapted for extruded decking. In light of these complexities, a need has developed to provide an improved system for assembling flooring or decking planks which uses fewer components parts, is easier to assemble and is less expensive. In response to this need, the present invention provides an assembly and a fastener therefor which is simple but effective in securely retaining flooring planks to a support structure such as joists.
SUMMARY OF THE INVENTION
Accordingly, it is a first object of the present invention to provide consumers and building contractors with a relatively cost effective, secure and low maintenance flooring assembly, particularly for recycled plastic lumber.
Another object of the present invention is to provide an improved, easily-manufactured and cost-effective unitary fastener clip to securely retain flooring or decking in place.
A related object of the present invention is to provide a unitary fastener clip what will securely connect a series of flooring planks so that they are maintained flat and level with one another, while allowing the individual planks to expand and contract longitudinally according to weather and atmospheric condition.
A further object of the present invention is to provide a method if installing flooring using interconnecting flooring and the inventive unitary flooring fastener, with a minimum number of necessary components, and without specialized tools or expertise.
To achieve these objects and in accordance with the purposes of the invention, as embodied and broadly described herein, the present invention is directed to a flooring assembly comprising: a plurality of elongated flooring planks, wherein each of the elongated flooring planks has on opposing ends at least one of a tongue-containing first longitudinal edge and a groove-containing second longitudinal edge. This flooring assembly is arranged on a plurality of supporting members so that the tongue-containing first longitudinal edge of a first elongated flooring plank engages the groove-containing second longitudinal edge of a second flooring plank.
In addition, a plurality of clip units are utilized, wherein each of the clip units is fastened to the supporting members and are arranged between the elongated flooring planks. A distal end portion of each clip positioned between a lower face of said tongue-containing first longitudinal edge of the first elongated flooring plank and an upper face of the groove-containing second longitudinal edge of said second flooring plank. Each of the clip units exerts a force normal to the lower face of the tongue-containing first longitudinal edge of said first plank and the upper face of the groove-containing second longitudinal edge of a second flooring plank so as to retain said elongated flooring planks to the supporting members latitudinally, while permitting the elongated flooring to expand and contract longitudinally.
BRIEF DESCRIPTION OF THE DRAWINGS
Reference is now made to the drawings of the invention wherein:
FIG. 1 is a sectional view of one embodiment of the inventive assembly in exploded form to show greater detail;
FIG. 2 shows the assembly of FIG. 1 in a partially assembled state;
FIG. 3 shows a perspective view of one embodiment of the inventive fastener;
FIG. 4 shows a perspective view of a second embodiment of the inventive fastener;
FIG. 5 shows a perspective view of a third embodiment of the inventive fastener; and
FIG. 6 shows a connection between adjacent planks; and
FIG. 7 shows a side view of the inventive fastener.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The preferred embodiment of the inventive flooring assembly and fastener unit of the present invention is shown in FIGS. 1, 2 and 3 and is represented by reference numeral 1. The flooring assembly includes a plurality of elongated flooring planks 2 , 3 , and 4 . These elongated flooring planks 2 , 3 or 4 may be constructed of an extruded recycled plastic material, or other suitable flooring materials commonly used in construction. Each of the elongated flooring planks 2 , 3 and 4 , have on opposing ends at least one of a tongue-containing first longitudinal edge 5 and a groove-containing second longitudinal edge 6 . The elongated flooring planks 2 , 3 and 4 are arranged along a plurality of supporting members 7 , so that the tongue-containing first longitudinal edge 5 an elongated flooring plank 3 or 4 engages the groove-containing second longitudinal edge 6 of a second flooring plank 2 or 3 . The supporting members 7 may take the form of joists and may be constructed of wood.
A plurality of clip units 8 are used to fasten the plurality of flooring planks 2 , 3 or 4 to the supporting members 7 . Each of said clip units 8 may have a z-shape in vertical cross section. The base 8 a of each of the clip units 8 is fastened to a supporting member 7 and is arranged between the flooring planks, 2 , 3 , or 4, with a leg 8 c extending vertically therefrom. In an alternative embodiment, each clip unit 8 is comprised of a pair of prongs 10 a and 10 c extending downward from the base portion 8 a of the clip units 8 . The pair of prongs 10 b and 10 c engage the supporting member 7 when the clip units 8 are fastened thereto.
A free, distal end portion 8 d of each clip unit 8 is attached perpendicular to the vertical leg 8 c and parallel to the base 8 a . The distal end portion 8 d is positioned between a lower face 5 a of the tongue-containing first longitudinal edge 5 of elongated flooring planks 3 or 4 and an upper face 6 a of the groove-containing second longitudinal edge 6 of second flooring planks 2 or 3 . Each of the clip units 8 used to construct flooring assembly 1 is usually fastened to each of the supporting members 7 in a spaced apart relationship.
When the flooring is fully assembled as shown in FIGS. 1, 2 and 3 , each of the clip units 8 exerts a force perpendicular to the lower face 5 a of the tongue-containing first longitudinal edge 5 of the first plank 3 or 4 and to the upper face 6 a of the groove-containing second longitudinal edge 6 of the second plank 2 or 3 , so as to retain the elongated flooring planks 2 , 3 or 4 to said supporting members 7 latitudinally, while permitting the elongated flooring planks 7 to expand and contract longitudinally according to usage, weather or atmospheric conditions.
Referring now to FIGS. 1, 3 , 6 and 7 , the preferred embodiment of the 8 is described. In FIGS. 1 and 3, the clip units 8 used to fasten the elongated flooring planks 2 , 3 and 4 to a support surface 7 are comprised of a base 8 a and at least one fastening means 8 b to secure the base 8 a to support surface 7 . A leg 8 c extends vertically from the base 8 a . A free, distal end portion, 8 d extends perpendicular to the leg 8 c , and is spaced apart from, and parallel to, the base 8 and is sized to engage a groove-containing second longitudinal edge 6 of a plurality of flooring planks 3 or 4 to retain the flooring planks 3 or 4 against the support surface 7 .
Again referring to FIGS. 1, 2 , 6 and 7 , the clip unit 8 is fastened to the supporting member 7 by a screw 8 b , which is inserted through a single aperture 8 e in the base 8 a , through which the screw 8 b engages the support member 7 and the base 8 a . The single aperture 8 e in the base 8 a of clip unit 8 may be offset from the center point represented by the intersection of broken reference lines 12 , so as to be positioned in close proximity to leg 8 c . This is an important feature of the present invention, as it prevents clip 8 from bending upward during use, which allows a smaller clip 8 to be used to secure the elongated flooring 2 , 3 and 4 to the supporting members 7 . This feature may also be incorporated into the alternative embodiments of the clip units 9 and 10 shown in FIGS. 4 and 5.
The single aperture 8 e may be countersunk 8 f in order to allow the head of the screw 8 b to rest flush and level with the upper surface of the base 8 a . This feature allows the elongated flooring planks 2 , 3 and 4 to lie flat and level with each other on the supporting members 7 , thus enhancing the utility and aesthetic desirability of the flooring assembly 1 .
In alternative embodiments of the invention shown in FIGS. 2, 4 and 5 , the clip units 9 and 10 include fastening means comprised of two apertures 9 e and 10 b arranged adjacent to one another in the base 9 a and 10 a , and through which two screws 9 b and 10 c engage the support surface 7 and the base 9 a and 10 a . Each of the two apertures may be countersunk (not shown), in order to allow the heads of the screws 9 b and 10 c to rest flush and level with the upper surface of the base 9 a and 10 a . This allows the elongated flooring planks 2 , 3 and 4 to lie flat on the supporting members.
Referring now to FIG. 5, the clip unit 10 includes an additional fastening means comprised of two prongs 10 d and 10 e attached to opposing sides of the base 10 a and extending downward therefrom. As shown in FIG. 2, the prongs 10 d and 10 e are inserted into the material of the supporting member 7 in order to prevent movement of the clip unit 8 .
The present invention also includes a method, shown in FIG. 3, of constructing a flooring assembly I which comprises the steps of providing a plurality of elongated floor planks 2 , 3 and 4 with opposing longitudinal edges 5 and 6 , clip units 8 and supporting members 7 and fastening the clips 8 units in spaced apart relationship along the supporting members 7 to support the plurality of elongated floor planks 2 , 3 and 4 . This method also includes the steps of arranging the elongated floor planks 2 , 3 and 4 on the supporting members 7 in a side-by-side relationship to create a substantially flat, level flooring.
The preferred embodiment of this method also requires the positioning of the clip units 8 between the opposing longitudinal edges 5 and 6 of the adjacent elongated floor planks 2 , 3 and 4 to retain these floor planks 2 , 3 and 4 on the supporting members.
In alternative embodiments of this method, shown in FIG. 2, clip unit 8 may include means, such as prongs 10 d and 10 e , which securely affix the clip unit 8 to supporting member 7 . As a result, the clip units 8 are fastened in such a way as to further prevent rotation thereof.
Of course, various changes, modifications and alterations from the teachings of the present invention may be contemplated by those skilled in the art without departing from the intended spirit and scope thereof. It is intended that the present invention only be limited by the terms of the appended claims.
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A flooring assembly and fastener therefor comprises flooring planks, preferably made of recycled lumber, and a clip fastener arranged between opposing longitudinal edges of the planks. The planks, in one embodiment, use tongue and groove construction. The clip is Z-shaped in cross section, one end portion of the clip catching the groove of a plank with the other end portion acting as a base for fastening to the joist. The clip fasteners are spaced along each joint and adjacent joints to retain the planks on the joists while permitting the planks to expand and contract at rates different than the joists themselves.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims a benefit of priority under 35 U.S.C. §119 to Provisional Application No. 61/985,328 filed on Apr. 28, 2014, which is fully incorporated herein by reference in its entirety.
BACKGROUND INFORMATION
Field of the Disclosure
Examples of the present disclosure are related to systems and methods for filling inoculations. More particularly, embodiments relate to dynamically filling inoculations in proper quantities within a closed, sterilized environment.
Background
Inoculations, vaccinations, immunizations, etc. refer to the process of artificial induction of immunity against various diseases. Specifically, inoculation refers to a process done in vitro, wherein microorganisms are transferred into laboratory equipment (e.g. test tubes, petri dishes, etc.), and later into a patient. Conventionally, inoculations include a plurality of parts, such as a vaccine and a diluent. Different inoculations require different vaccines and different amounts of diluent to function properly.
In certain circumstances, the inoculations are required to be used in remote areas outside of a clinical or laboratory setting. However, vaccines have an expiration period, wherein the vaccines may not be prepared or mixed in final form in a laboratory and then later used. When medical practitioners are creating or mixing (reconstituting) inoculations in the field and in the clinical environment, they are required to spend an enormous amount of time preparing the inoculations individually. This is because the medical practitioners must create new inoculations, ensure whether previously created inoculations have expired, are spoiled, and what amount of diluent to apply to different inoculations, etc.
Accordingly, needs exist for more effective and efficient systems and methods to dynamically fill inoculations in proper quantities within a closed, sterile environment.
SUMMARY
Embodiments disclosed herein describe systems and methods to dynamically fill inoculations in proper quantities within a closed, sterile environment.
Embodiments are directed towards a multi-dose prefilled reconstituted device (MPRD). The MPRD may be configured to automatically prepare a plurality of vials for inoculations quickly and accurately. In embodiments, the MPRD is a transportable device that may be moved from a laboratory environment to a field environment and/or a clinical environment. By utilizing the MPRD to automatically prepare vials for inoculations, human interaction and human error may be minimized, which may increase the amount of vials for inoculations that can be prepared over a given time period.
In embodiments, the MPRD may be a stationary or a portable device and self-contained system with a computer processor configured to automatically reconstitute vaccines and medications, such as lyophilized medications and liquid medications. The MPRD may be configured to automatically load a diluent, in the proper quantities, to fill the vials including the lyophilized medication.
In embodiments, the MPRD may include a scanning device configured to determine a diluent cartridge that is stored within the system. Responsive to determining the vaccines and/or medications with the MPRD, the MPRD may determine the volume of diluent to be loaded into a vial with the lyophilized medication. Therefore, vials for inoculations may be dynamically created in a sterile environment and remote environment.
In embodiments, the MPRD may include a quantity measuring device configured to determine the number of vials loaded on a carousel or in a linear cartridge for reconstruction of the inoculation. Responsive to the quantity measuring device determining the number of vials on the carousel or in the linear cartridge, the MPRD may load the determined number of vials with the diluent.
In embodiments, either a carousel or linear cartridge including a plurality of vials may be configured to be interfaced with the MPRD. In embodiments, a first carousel may be removed from the MPRD and a second carousel may be inserted into the MPRD. The carousels and linear cartridges may be interchangeable cartridges that may be inserted and removed into a sterile environment; the MPRD may be configured to hold multiple linear cartridges or carousels simultaneously. In embodiments, the vials or other containers within the carousels or linear cartridges may be preloaded with medication before being inserted into the MPRD. Responsive to determining that the medication within the inserted carousel or linear cartridge is mapped with the medication within the diluent, each of the vials or containers within the carousels or linear cartridges may be automatically mixed with a proper amount of diluent. Accordingly, different medications may be mixed with different quantities of diluent.
In embodiments, the MPRD may include GPS or location tracking devices that are configured to determine the locations where inoculations are reconstituted.
In embodiments, the MPRD may also include a memory device configured to store software to capture individual patient, administrator and demographic information for tracking and epidemiology. The memory device may also be configured to capture amount of vials, containers, medication and diluent processed by the MPRD for inventory management purposes.
These, and other, aspects of the invention will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. The following description, while indicating various embodiments of the invention and numerous specific details thereof, is given by way of illustration and not of limitation. Many substitutions, modifications, additions or rearrangements may be made within the scope of the invention, and the invention includes all such substitutions, modifications, additions or rearrangements.
BRIEF DESCRIPTION OF THE DRAWINGS
Non-limiting and non-exhaustive embodiments of the present invention are described with reference to the following figures, wherein like reference numerals refer to like parts throughout the various views unless otherwise specified.
FIG. 1 depicts a topology for a medical processing system, according to one embodiment.
FIG. 2 depicts a method for distributing diluent from a diluent cartridge into a vial utilizing an MPRD, according to an embodiment.
FIG. 3 depicts a diluent cartridge and a MPRD, according to an embodiment.
FIG. 4 depicts a topology for a medical processing system, according to one embodiment.
FIG. 5 depicts a linear cartridge system, according to one embodiment.
Corresponding reference characters indicate corresponding components throughout the several views of the drawings. Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments of the present disclosure. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of these various embodiments of the present disclosure.
DETAILED DESCRIPTION
In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present embodiments. It will be apparent, however, to one having ordinary skill in the art that the specific detail need not be employed to practice the present embodiments. In other instances, well-known materials or methods have not been described in detail in order to avoid obscuring the present embodiments.
Embodiments disclosed herein describe systems and methods dynamically filling inoculations in proper quantities. By utilizing a MPRD to automatically prepare vials or other containers, human error may be minimized, which may increase the amount of vials or containers for inoculations that can be prepared over a given time period. Moreover, within the system, all vials or containers may be filled simultaneously, offering significant time savings potential.
FIG. 1 depicts one embodiment of a topology 100 for a medical processing system including a diluent cartridge 110 , MPRD 120 , and carousel 140 . Diluent cartridge 110 and MPRD 120 may be configured to interface with each other to dynamically and automatically produce inoculations in a closed, sterile environment.
Diluent cartridge 110 may be a transportable cartridge that is configured to store at least one diluent for an inoculation. Diluent cartridge 110 may include one or more diluent reservoirs 112 and a unique identifier 114 . The one or more diluent reservoirs 112 may be configured to store diluent, wherein the diluent stored in diluent reservoir 112 may be configured to be transferred to MPRD 120 to create an inoculation. Unique identifier 114 may be the name of the diluent, bar code identification number, Q-code, etc. Unique identifier 114 may be utilized by MPRD 120 to determine that the correct diluent stored in diluent reservoir 112 is combined with a medication stored within MPRD 120 . The unique identifier 114 may utilized to determine information associated with the diluent, diluent reservoirs, etc. For example, the unique identifier 114 may be linked to a database identifying the total quantity of diluent with each reservoir, the type of diluent within each reservoir, the quantity of diluent stored within each reservoir, the location of each diluent within each reservoir, etc.
Carousel 140 may be a hardware device including a unique identifier 142 and a plurality of vials 144 . Carousel 140 may be shaped to be inserted into and removed from MPRD 120 . After vials 144 receive a diluent, carousel 140 may be removed from MPRD 120 and a new carousel may be inserted into MPRD 120 . Accordingly, vials 144 may not be removed from MPRD 120 , while carousel 140 is inserted into MPRD 120 . In embodiments, carousel 140 may be circularly shaped, such that at least a portion of carousel 140 may be rotated within MPRD 120 .
MPRD 120 may be a hardware device configured to receive diluent from diluent cartridge 110 , receive a vial or other containers with a lyophilized medication or liquid medication (referred to individually and collectively hereinafter as “medication”), and mix the diluent with the medication to form an inoculation. MPRD 120 may include an inner chamber, wherein the inner chamber is a sterile environment configured to store inoculations. The sterile environment may include a low level of environmental pollutants, dust, airborne microbes, aerosol particulars, and chemical vapors. MPRD 120 may be configured to create inoculations based on the components within MPRD 120 , diluent cartridge 110 , and carousel 140 .
MPRD 120 may include processing device 122 , communication device 123 , memory device 124 , temperature module 126 , injection interface 160 , carousel interface 128 , identification module 130 , logic module 132 , and graphical user interface 134 .
Processing device 122 can include memory, e.g., read only memory (ROM) and random access memory (RAM), storing processor-executable instructions and one or more processors that execute the processor-executable instructions. In embodiments where processing device 122 includes two or more processors, the processors may operate in a parallel or distributed manner. Processing device 122 may execute an operating system of MPRD 120 , firmware for MPRD 120 , or software associated with other elements of MPRD 120 .
Communication device 123 may be a device that allows MPRD 120 to communicate with another device, e.g., a firmware server, diluent cartridge 110 , or another networked device. Communication device 123 may include one or more wireless transceivers for performing wireless communication and/or one or more communication ports for performing wired communication. In embodiments, communication device 123 may be configured to communicate data over a wired or wireless network such as the Internet, an intranet, a LAN, a WAN, a NFC network, Bluetooth, infrared, radio frequency, a cellular network, satellite network or another type of network.
Memory device 124 may be a device configured to store data generated or received by MPRD 120 . Memory device 124 may include, but is not limited to a hard disc drive, an optical disc drive, and/or a flash memory drive, including a slot for an SD card or similar solid state storage. Multiple memory devices may exist on the MPRD, both removable and non-removable. In embodiments, memory device 124 may include a database that includes entries associated with diluent cartridges 110 , carousels 140 , and/or a mapping between the diluent cartridges 110 and carousels 140 . The entries associated with diluent cartridges 110 may include information associated with unique identifiers 114 associated with diluent cartridge 110 , the name of the diluent within diluent cartridge 110 , the amount of diluent within diluent cartridge 110 , etc. The entries associated with carousel 140 may include information associated with a unique identifier 142 associated with carousel 140 , a number of vials 144 within carousel 140 , medication within each of the vials 144 , a lower temperature threshold and/or an upper temperature threshold associated with carousel 140 , wherein if a recorded temperature is outside of the temperature thresholds the medication may become spoiled, an expatriation date associated with the medication, etc.
The mapping between the diluent cartridges 110 and carousels 140 may indicate which carousels 140 may be able to receive diluent from diluent cartridges 110 . If a carousel 140 is not mapped to a diluent cartridge 110 , then the carousel may not receive the diluent from the diluent cartridge 110 . Furthermore, the mapping may indicate how much diluent from diluent cartridge 110 should be displaced into a vial 144 located within carousel 140 . The mappings may also include locations within the diluent reservoirs 114 that are mapped to vials 144 within a carousel 140 . Accordingly, in embodiments, a first subset of the diluent reservoirs 112 may be allocated to certain vials 144 , while a second subset of diluent reservoirs 112 may not be allocated to a carousel 140 . This may be based on the type of medications associated with the vials 144 , or other factors. In embodiments, if the unique identifier 114 associated with diluent cartridge 110 is not associated with a unique identifier 142 associated with carousel 140 within the mapping, the diluent 110 within diluent cartridge 110 may not be placed into a vial 144 .
Temperature module 126 may be a hardware processing device configured to determine the temperature within MPRD 120 and/or carousel 140 . Temperature module 126 may be configured to determine the temperature within MPRD 120 and/or carousel 140 at set intervals, which may be any desired period of time (e.g., every 1/10 th of a second, every second, every minute, every ten minutes, etc.), responsive to communication device 124 transmitting and/or receiving information, responsive to carousel 140 being inserted into MPRD 120 , responsive to diluent cartridge 110 being inserted into MPRD 120 , or a combination. Responsive to temperature module 126 determines the temperature within MPRD 120 and/or carousel 140 , temperature module 126 may transmit the temperature to memory device 124 to be stored.
Upon a carousel 140 being inserted within MPRD 120 , temperature module 126 may be configured to determine the upper and lower temperature thresholds associated with the carousel 140 by parsing the corresponding entry within memory device 124 for the carousel 140 . If temperature module 126 determines that the temperature is outside of the upper or lower temperature thresholds associated with carousel 140 , then temperature module 126 may transmit data to memory device 124 indicating that the vials 144 within carousel 140 are spoiled and should not be used for inoculations. Temperature module 126 may be affixed to carousel 140 , such that temperature module 126 may continuously determine the temperature associated with carousel 140 . In embodiments, different carousels 140 may have different temperature thresholds.
Injection interface 160 may be configured to receive a diluent from diluent cartridge 110 and place the diluent into vial 144 loaded within carousel 140 . Because MPRD 120 is a sterile environment, diluent cartridge 110 may not be inserted into the inner chamber of MPRD 120 . Injection interface 160 may include input port 150 , tubing 152 , and outlet port 154 . Input port 150 may be configured to interface with an outlet of diluent cartridge 110 , such that fluid may be transferred from diluent cartridge 110 into input port 150 . In embodiments, the input port 150 may only be configured to interface with diluent cartridge 110 , and may be a separate interface from carousel interface 150 . Tubing 152 may be a series of pipes, tubes, or any other structures with a hollow section that a diluent may flow through.
Outlet port 154 may be a device that is configured to receive diluent via tubing, and distribute the diluent into vials 144 . Outlet port 154 may include a syringe, pump, or any other device 156 that may direct the flow of the diluent. In embodiments, input port 150 , tubing 152 , and/or outlet port 154 may be removable devices, wherein the devices may be removed for sanitization purposes and/or to ensure that the correct diluent is distributed into vials 144 . The syringe 156 may be configured to output the diluent directly into vials 144 , wherein vials 144 may not be removed from MPRD 120 while carousel 120 is inserted into MPRD 120 .
Carousel interface 128 may be a hardware device configured to receive, store, and hold a carousel 140 inserted into MPRD 120 . Carousel 140 may be configured to rotate within MPRD 120 to align a first, upper end of vials 144 with outlet port 154 to receive the diluent. In embodiments, the entirety of carousel 140 may be configured to be inserted within MPRD 120 , while vials 144 are receiving diluent. Before inserting carousel 140 into MPRD 120 , medicine may be displaced within each of the vials 144 . When the medicine is combined with the diluent an inoculation may be formed. Because carousels 140 may store medicine that has an expiration period, carousels 140 may have an expiration date, which may be stored in an entry of memory device 124 corresponding to unique identifier 142 associated with carousel 140 . If carousel 140 is placed within MPRD 120 after an expiration date associated with carousel 140 , then carousel 140 may not be able to receive the diluent from the diluent cartridge 110 . In embodiment, carousel interface 128 may be configured to rotate while positioned within carousel interface 128 . The angle of rotation of carousel 140 may be perpendicular
In embodiment, carousel interface 128 may be configured to rotate while positioned within carousel interface 128 . The direction of rotation of carousel 140 may be perpendicular to a direction that syringed 156 place diluent within vials 144 . Furthermore, the angle of rotation of vials 144 within carousel 140 may be perpendicular to the direction of rotation of carousel 140 .
Identification module 130 may be a hardware processing device configured to determine a unique identifier associated with diluent cartridge 110 and/or carousel 140 . In embodiments, identification module 130 may be configured to obtain an image of the unique identifier associated with the diluent cartridge 110 and/or carousel 140 , and parse memory device 124 to determine a matching unique identifier. Responsive to determining matching unique identifiers, identification module 130 may transmit the corresponding information associated with the unique identifier stored within memory device 124 to logic module 132 . In embodiments, if identification module 130 cannot determine a unique identifier associated with diluent cartridge 110 and/or carousel 140 , identification module 130 may determine that either diluent cartridge 110 and/or carousel 140 may not be used for inoculations. Accordingly, identification module 130 may determine the unique identifiers associated with diluent cartridge 110 and/or carousel 140 without communicating date to or from MPRD 120 .
Logic module 132 may be a hardware processing device configured to determine the quantity and/or timing of when diluent from diluent cartridge 110 is distributed to vials 144 within carousel 140 . Logic module 132 may be configured to transmit instructions to injection interface 160 to move the diluent responsive to identification module 130 determining what diluent cartridge 110 and/or carousel 140 are interfaced with MPRD 120 , information associated with diluent cartridge 110 and/or carousel 140 (e.g. temperature thresholds, expiration dates, etc.) stored within memory device 124 , and/or the mapping between the identified diluent cartridge 110 and carousel 140 . Logic module 132 may be configured to determine to inject diluent from diluent cartridges 110 to vials 144 responsive to determining that the temperatures are within the desired temperatures thresholds, within a given time period of a carousel 140 being inserted into MPRD 120 , etc. For example, if within a given time period after carousel 140 being inserted into MPRD 120 , the temperature within MPRD 120 does not fall between the desired temperature thresholds, logic module 132 may determine to not move the diluent into vials 144 . However, if within the given time period after carousel 140 being inserted into MPRD 120 , the temperature within MPRD 120 does fall between the desired temperature thresholds, logic module 132 may determine to automatically move the diluent into vials 144 .
In embodiments, the mapping may include information associated with the number of vials 144 within carousel 140 that may be filled with diluent from diluent cartridge 110 , the amount of diluent to be displaced within each vial 144 , how many vials 144 to automatically fill with diluent from diluent cartridge 110 , etc. In embodiments, if there is not a mapping between the unique identifiers of diluent cartridge 110 and/or carousel 140 , then logic module 132 may transit instructions to identification module 130 to not distribute the diluent from diluent cartridge 110 to injection interface 160 . For example, the mapping may include information to fill a desired number of vials 144 within carousel 140 with diluent from diluent cartridge, wherein the desired number may be all of the vials 144 within carousel 140 or only a subset of the vials 144 within carousel 140 .
Graphical user interface 134 may be a device that allows a user to interact with MPRD 120 over a network. While one user interface is shown, the term “user interface” may include, but is not limited to being, a touch screen, physical keyboard, mouse, camera, video camera, microphone, and/or speaker. Utilizing graphical user interface 134 , a user may perform actions to enter information associated with a diluent cartridge 110 , carousel 140 , and/or MPRD 120 .
FIG. 2 depicts a method 200 for distributing diluent from a diluent cartridge into a vial utilizing an MPRD, according to an embodiment. The operations of method 200 presented below are intended to be illustrative. In some embodiments, method 200 may be accomplished with one or more additional operations not described, and/or without one or more of the operations discussed. Additionally, the order in which the operations of method 200 are illustrated in FIG. 2 and described below is not intended to be limiting.
In some embodiments, method 200 may be implemented in one or more processing devices (e.g., a digital processor, an analog processor, a digital circuit designed to process information, an analog circuit designed to process information, a state machine, and/or other mechanisms for electronically processing information). The one or more processing devices may include one or more devices executing some or all of the operations of method 500 in response to instructions stored electronically on an electronic storage medium. The one or more processing devices may include one or more devices configured through hardware, firmware, and/or software to be specifically designed for execution of one or more of the operations of method 200 .
At operation 210 , a diluent cartridge 110 may be inserted into an MPRD 120 . Responsive to diluent cartridge 110 being inserted into MPRD 120 , a unique identifier associated with diluent cartridge 110 may be determined. Operation 210 may be performed by an identification module that is the same as or similar to identification module 130 , in accordance with one or more implementations.
At operation 220 , a carousel 140 including a plurality of vials 144 may be inserted into MPRD 120 . Responsive to carousel 140 being inserted into MPRD 120 , a unique identifier associated with carousel 140 may be determined. Operation 220 may be performed by an identification module that is the same as or similar to identification module 130 , in accordance with one or more implementations.
At operation 230 , a mapping between the unique identifier associated with carousel 140 and diluent cartridge 110 may be determined. The mapping between the unique identifiers may be determined by comparing the unique identifier associated with carousel 140 and/or diluent cartridge 110 with unique identifiers stored within a memory device. Responsive to matching a unique identifier with a carousel 140 , it may be determined if an entry associated with the carousel within the database is associated with the unique identifier with the diluent cartridge 110 , or vice versa. Operation 230 may be performed by a logic module that is the same as or similar to logic module 132 , in accordance with one or more implementations.
At operation 240 , responsive to determine a carousel 140 is linked with diluent cartridge 110 , diluent from diluent cartridge 110 may be distributed to a vial within carousel 140 . In embodiments, the amount of diluent distributed to the vial may be based on information corresponding to the mapping stored within the memory device, wherein vials within different carousels 140 may receive different amounts of diluent and different vials within the same carousel 140 may receive different amounts of diluent. Operation 240 may be performed by a logic module that is the same as or similar to logic module 132 , in accordance with one or more implementations.
At operation 250 , diluent cartridge 110 and/or carousel 140 may be removed from MPRD 120 , and a second diluent cartridge 110 and/or carousel 140 may be inserted into MPRD 120 . Operation 250 may be performed by an injection interface that is the same as or similar to injection interface 160 , in accordance with one or more implementations.
FIG. 3 depicts one embodiment of a diluent cartridge 110 and a MPRD 120 . One skilled in the art will appreciate that the placement of elements within or on diluent cartridge 110 and MPRD 120 may be changed, substituted for other elements, and/or removed entirely from the system.
FIG. 4 depicts a topology for a MPRD 400 , according to one embodiment. Elements of FIG. 4 are described above. Therefore, for the sake of brevity another description of these elements is omitted.
As depicted in FIG. 4 , MPRD 400 may include a linear cartridge 410 that is configured to be received by a linear cartridge interface 420 . Linear cartridge 410 may be configured to hold vials with an inoculant. Linear cartridge interface 420 is configured to receive the linear cartridge 410 , and inject diluent into the vials.
Embodiments that utilize linear cartridge 410 may consume less power than other embodiments. The cartridge system is a lower power consumption, yet lower throughput, option to the carousel. Embodiments utilizing a carousel may require motors that can be heavy and utilize a lot of power. While embodiments utilizing a linear cartridge 410 may allow linear cartridge 410 to be manually inserted and removed from MPRD 400 .
MPRD 400 may utilize injectors for the linear cartridge 410 . The injections would be a straight injector strip with needles (injectors), wherein the injectors are positioned over the vials or containers once linear cartridge 410 is inserted within MPRD 400 . For example, if there are to be ten vials in cartridge 410 , then there would be ten needles on the injector strip. In embodiments, the injector may be a removable device that is configured to be slide in and out of a slot on the side of the MPRD 400 . These linear cartridges are also simpler for backpacks, fitting many more vials into a single backpack than you can get with a carousel.
In embodiments, MPRD 400 may be configured to receive a plurality of linear cartridges 410 simultaneously. Additionally, MPRD 400 may include a plurality of injectors. Therefore, a plurality of linear cartridges 410 may be inserted into a plurality of receiving doors within MPRD 400 . For example, five linear cartridges 410 with ten vials each could be simultaneously loaded into MPRD 400 . Then, injectors aligned with the different linear cartridges 410 may simultaneously insert diluent into the vials on the different linear cartridges 410 .
FIG. 5 depicts one embodiment of a linear cartridge 500 . Linear cartridge 500 may be a container holding vaccine vials or containers. Linear cartridge 500 may be configured to slide through a door into the MPRD 400 . Once inside, the linear cartridge 500 rests on a platform that has a small motor for shaking the vials when called for and for ejection of the vials when reconstitution is complete. In embodiments, this may be useful for maintaining sterile conditions on the injectors and the tops of the vaccine vials or containers. A reader within the MPRD moves along the belt inside the device identifying what the vials contain via bar code, OCR, or other method for identifying contents from the labels on the vials or containers. The reader can be moved by a stepper motor or similar mechanical device.
The injectors within MPRD 400 may be positioned on a strip above the linear cartridge 410 inside MPRD 400 . When the user is ready to inject diluent into the vials or containers, the injectors come down inserting their needles into the vials or containers at the same time. Once the diluent is injected, the injectors move away from the vials and the cartridge containing the medication. The linear cartridge 410 can be ejected through the door manually by pressing a button or automatically ejected via the system firmware upon completion of the injection of diluent, and shaking of the vials or containers when desired or necessary.
Although the present technology has been described in detail for the purpose of illustration based on what is currently considered to be the most practical and preferred implementations, it is to be understood that such detail is solely for that purpose and that the technology is not limited to the disclosed implementations, but, on the contrary, is intended to cover modifications and equivalent arrangements that are within the spirit and scope of the appended claims. For example, it is to be understood that the present technology contemplates that, to the extent possible, one or more features of any implementation can be combined with one or more features of any other implementation.
Reference throughout this specification to “one embodiment”, “an embodiment”, “one example” or “an example” means that a particular feature, structure or characteristic described in connection with the embodiment or example is included in at least one embodiment of the present invention. Thus, appearances of the phrases “in one embodiment”, “in an embodiment”, “one example” or “an example” in various places throughout this specification are not necessarily all referring to the same embodiment or example. Furthermore, the particular features, structures or characteristics may be combined in any suitable combinations and/or sub-combinations in one or more embodiments or examples. In addition, it is appreciated that the figures provided herewith are for explanation purposes to persons ordinarily skilled in the art and that the drawings are not necessarily drawn to scale.
Embodiments in accordance with the present invention may be embodied as an apparatus, method, or computer program product. Accordingly, the present embodiments may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, micro-code, etc.), or an embodiment combining software and hardware aspects that may all generally be referred to herein as a “module” or “system.” Furthermore, the present invention may take the form of a computer program product embodied in any tangible medium of expression having computer-usable program code embodied in the medium.
Any combination of one or more computer-usable or computer-readable media may be utilized. For example, a computer-readable medium may include one or more of a portable computer diskette, a hard disk, a random access memory (RAM) device, a read-only memory (ROM) device, an erasable programmable read-only memory (EPROM or Flash memory) device, a portable compact disc read-only memory (CDROM), an optical storage device, and a magnetic storage device. Computer program code for carrying out operations of the present invention may be written in any combination of one or more programming languages.
The flowcharts and block diagrams in the flow diagrams illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in the flowcharts or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It will also be noted that each block of the block diagrams and/or flowchart illustrations, and combinations of blocks in the block diagrams and/or flowchart illustrations, may be implemented by special purpose hardware-based systems that perform the specified functions or acts, or combinations of special purpose hardware and computer instructions. These computer program instructions may also be stored in a computer-readable medium that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable medium produce an article of manufacture including instruction means which implement the function/act specified in the flowcharts and/or block diagrams.
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Embodiments disclosed herein describe systems and methods for systems and methods to dynamically filling inoculations in proper quantities. Embodiments are directed towards a multi-dose prefilled reconstituted device (MPRD) that is configured to automatically prepare a plurality of vials for inoculations quickly and accurately, wherein the MPRD is a transportable device that may be moved from a laboratory environment to a field environment and/or a clinical environment.
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BACKGROUND OF THE INVENTION
The present invention refers to a superposed drilling device wherein impacts are transmitted onto a solid drill bit, and which is provided with an annular drill bit that is impact-coupled to the solid drill bit so that the impact is transmitted from the solid drill bit onto the annular drill bit.
In superposed drilling, used in ground boring and rock drilling, two coaxial drill strings are employed. The inner string is provided with a solid drill bit and the outer string is provided with an annular drill bit surrounding the solid, drill bit. Both strings are advanced rotatingly, the inner string possibly being subjected to impacts. Such impacts may either be generated by an external hammer provided outside the borehole and at the rear end of the inner string, or a deep-hole hammer arranged near the solid drill bit along the longitudinal axis of the inner string. Impacts dealt on the outer string would be absorbed for a large part by the surrounding earth so that they would reach the annular drill bit with a greatly reduced impact energy.
U.S. Pat. No. 3,682,260 describes a superposed drilling wherein a deep-hole hammer strikes the solid drill bit. The solid drill bit and the annular drill bit have cooperating impact transmission surfaces by which the impacts are transmitted from the solid drill bit onto the annular drill bit. In this manner, both drill bits are operated by rotation and impacts, although the annular drill bit has no impact drive means of its own. It is a drawback, however, that upon each blow, the annular drill bit is pulled forward on the outer string so that the outer string is subjected to considerable impact tensile stress. Thus, the threads of the outer pipe string may be damaged or break.
German Patent 21 55 540 describes an improved superposed drilling device wherein the annular drill bit is guided by means of keybeds so as to be longitudinally displaceable at an end piece of the outer string. Also in this case, the impacts are transmitted from the solid drill bit onto the annular drill bit by impact transmitting surfaces so that both drill bits are driven by impacts. The engaging keybeds, provided at the annular drill bit and at the end piece of the outer pipe, which allow for the axial displacement of the annular drill bit upon each impact without stressing the outer pipe string, form bottlenecks in which bore material may gather. In practice, the keybeds are clogged with the loosened bore material so that a displaceability of the annular drill bit is no longer ensured. It may then occur that the impacts are no longer transmitted onto the annular drill bit or that the impacts transmitted onto the annular drill bit do generate considerable tensile stress in the outer pipe string and cause strain thereon. The keybeds or the splines may also jam, thereby impairing the displaceability of the annular drill bit. Drilling devices using an impact transmission from the solid drill bit onto the annular drill bit were not successful in practice due to the above drawbacks.
SUMMARY OF THE INVENTION
It is the object of the invention to provide a superposed drilling device wherein a transmission of impacts from the solid drill bit onto the annular drill bit is performed, and which is not susceptible to malfunctions and jamming caused by bore material.
According to the present invention, the object is solved with the features of claim 1.
In the device of the present invention, the annular drill bit is displaceably mounted at the outer pipe end piece by virtue of the annular drill bit having rearwardly projecting axial tongues engaging corresponding windows in the outer pipe end piece. These windows are apertures in the wall of the outer pipe end piece and are more or less closed by the tongues of the annular drill bit depending on the respective axial displacement of the annular drill bit. The annular drill bit has no grooves or indentations on its circumference. Consequently, no gaps can occur in which the bore material could be compressed. When the annular drill bit is in the front end position, the windows are opened and scavenged by the scavenging agent supplied thereto. There are no dead corners that cannot be scavenged. The tongues of the annular drill bit engage the windows of the outer pipe end piece in the manner of a claw clutch, thereby ensuring a rotational engagement.
The number of the tongues and windows may be greatly reduced so that the intermediate wall portions separating the tongues and windows each have a sufficient circumferential extension and sufficient strength. At least two tongues are provided, yet, preferably, four tongues are employed. The tongues have approximately the same width as the spaces between the tongues so that a uniform load distribution is obtained.
Suitably, the windows of the outer pipe end piece are open to the front end, where they are delimited by an annular band surrounding the outer pipe end piece, which annular band simultaneously serves to prevent a spreading of the tabs defining the windows. The annular band further serves to limit the forward movement of the annular drill bit since it serves as a stop for a head projecting outward from each tongue.
To prevent the tongues of the annular drill bit from bending inward, they are radially supported by the shaft of the solid drill bit or a pipe piece enclosing this shaft.
The ends of the tongues are suitably pointed to form stripping edges so that remainders of bore material that could impair the displaceability of the annular drill bit, are stripped off to the outside and cannot form dangerous gatherings.
BRIEF DESCRIPTION OF THE DRAWINGS
The following is a detailed description of embodiments of the present invention taken in conjunction with the accompanying drawings in which:
FIG. 1 is a side elevational view of the drilling device with a deep-hole hammer,
FIG. 2 is a longitudinal section of the drilling device of FIG. 1, and
FIG. 3 is a longitudinal section of a drilling device wherein the impacts are generated by an external hammer.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The drawings illustrate the end of an outer pipe string 10 and an inner pipe string 11 at the borehole side. The rear ends of both drill strings 10 and 11 may be driven by a double-headed drilling machine arranged outside the borehole and having a sledge displaceable on a carriage. Provided on this sledge are two drill units that are longitudinally displaceable relative to each other, the front drill unit rotating the outer pipe string 10 and the rear drill unit driving the inner pipe unit 11. The rotations may be effected with the same or different numbers of rotations, as well as in the same sense of rotation and in opposite senses of rotation, optionally. The drill means may also have a single rotary or rotary percussion drive acting upon the outer pipe and rotating the outer pipe.
In the embodiment of FIGS. 1 and 2, a generally tubular outer pipe end piece 12 is screwed to the front end of the outer pipe string 10 through a threading 13. This outer pipe end piece 12 has a conical portion 12a in which its wall thickness increases outward and to the front, namely to 1.5 times the wall thickness of the outer pipe string 10. The inner width, in contrast thereto, is equal over the entire length of the end piece 12 to the inner width of the outer pipe string 10.
At its front end, in the region of its greater wall thickness, the outer pipe end piece 12 is provided with tabs 14 projecting axially parallel and respectively defining windows 15. These windows 15 are rectangular apertures in the wall of the outer pipe end piece 12, i.e. they are portions in which the wall is completely removed. The apertures forming the windows 15 terminate freely at the front (i.e. borehole-side) end of the outer pipe end piece 12, since also the rectangular tabs 14 project freely and are not integrally interconnected at their ends.
In the present embodiment, four tabs 14 are evenly distributed along the circumference of the outer pipe end piece, the tabs laterally defining four windows 15. The width of each tab 14 is substantially equal to the width of a window 15.
Each tab 14 has an outer circumferential groove 16 near its front end. Seated in these circumferential grooves 16 is an annular band 17 encircling the circumference of the outer pipe end piece 12 in the area of the tabs 14 and defining the windows 15 to the front. The front edge 17a and the rear edge 17b of the annular band 17 are chamfered to form stripping edges.
The front end of the inner pipe string 11 is provided with a pipe piece 20, onto the rear end 21 of which a deep-hole hammer (not illustrated), arranged in the inner pipe string 11, strikes. By means of a thread 22 screwed into the outer pipe string 10, the pipe piece 20 is fixed so as to be axially displaceable within limits such that the pipe piece 20 can make limited axial movements relative to the inner pipe string 11. Keyings 23 and 24 at the pipe piece 20 and the surrounding screwed member 22 cause a rotary connection of the pipe piece 20 with the outer pipe string 11. The front shoulder of the keying 23 secures the pipe piece 20 against being pulled out from the screwed member 22 to the front. The pipe piece 20 has a rear annular shoulder 25 abutting against the front end of the screwed member 22, thereby defining the rearward movement of the pipe piece 20.
The pipe piece 20 extends forward beyond the front ends of the tabs 14 of the outer pipe end piece 12. The front end face 27 of the pipe piece 20 forms the rear end abutment of an annular collar 29 of the solid drill bit 28. The solid drill bit 28 has a drill bit shaft 28a extending into the pipe piece 20 and being connected to the pipe piece 20 by keyings 30 so as to be rotatable therewith, yet also axially displaceable. The conical front end face of the annular collar 29 forms a impact transmission surface 31. The drill bit head 32 of the solid drill bit 28 projects forward therefrom. Hard metal pins 33 for working on the bottom of the borehole are arranged on the end face of the drill bit head 32.
A scavenging channel 34 extending over the entire length of the solid drill bit 28, the scavenging channel being communicated with the inside of the inner drill string 11 via the inside of the pipe piece 20. Via this scavenging channel 34 having outlets in the drill bit head 32, a scavenging medium, e.g. air or water, is supplied to the bottom of the borehole. Wide backflush grooves 36 and 37 are provided in the flange 29 and at the circumference of the pipe piece 20, through which grooves the scavenging medium and the loosened bore material are flushed backward. These backflush grooves are in communication with the annular channel 38 between the outer pipe string and the inner pipe string. Outside the borehole, the scavenged material is discharged from this annular channel 38.
The front portion of the pipe piece 20, as well as the solid drill bit 28 are surrounded by an annular drill bit 40 that is studded with hard metal pins 41 at its front end. The annular drill bit has an annular drill bit head 42 and tongues 43 projecting rearward therefrom. Each of the tongues extends into one of the windows 15 of the outer pipe end piece 12 wherein they are axially displaceable. The spaces between two tongues 43 are respectively filled by one of the tabs 14 of the outer pipe end piece 12. The outer surfaces of the tongues 43 are on a (imaginary) cylinder surface having a diameter smaller than the outer diameter of the head piece 42. The step at the rear end of the head piece 42 is formed as an undercut 45.
At the rear end of each tongue, there is an outwardly projecting head 46 delimiting the forward movement of the annular drill bit 40 by abutting against the annular band 17 fixed at the outer pipe end piece 12. The front edge of the head 46 is formed as an undercut 47 which the stripping edge 17b of the annular band 17 can engage. The rear edge 48 of the head 46 is chamfered for forming a stripping edge.
Impacts exerted onto the impact surface 21 of the pipe piece 20 are transmitted via the impact transmission surface 31 onto the rear end surface 49 of the flange 29 of the solid drill bit 28 so that the drill bit head 32 strikes the bottom of the borehole.
The impact transmission surface 31 of the solid drill bit 28 cooperates with an impact transmission surface 50 within the annular drill bit 40 so that the impacts on the solid drill bit 28 are transmitted via the impact transmission surfaces 31 and 50 also onto the annular drill bit 40. The annular drill bit 40 may slide freely in the longitudinal direction, since its heads 46 can slide in the longitudinal direction within the windows 15. The drawings each illustrate a central position of the annular drill bit, the heads having free spaces in the windows 15, both in the frontward and the rearward directions. Impacts transmitted onto the annular drill bit 40 are not transmitted onto the outer pipe end piece 12 so that the outer pipe string 10 is not stressed by impacts.
Corresponding to the axial position of the annular drill bit 40 relative to the outer pipe end piece 12, the rear parts of te windows 15 are left open, while the front portions of these windows are closed by the tongues 43. Through the open portions of the windows 15, scavenging medium that has gotten into the area outside the drill bits can be lead into the backflush channel 38 and can be guided back between the outer and the inner pipe strings. The tongues 43 engaging the windows 15 further cause a rotary coupling of the annular drill bit 40 and the outer pipe end piece 12 fixedly mounted at the outer pipe string 10.
The front portion 52 of the pipe piece 20 between the annular shoulder 25 and the front end surface 27 has an outer diameter that is as large as to support the tongues 43 from inside and to prevent the tongues 43 from bending inward. Thus, it is ensured that the tongues 43 cannot slip from under the annular band 17 due to an inwardly directed bending.
In the described embodiment of FIGS. 1 and 2, a deep-hole hammer is provided within the inner pipe 11, which strikes on the rear end 21 of the pipe piece 20 and the impacts of which are transmitted from the pipe piece 20 onto the drill bit shaft 28a. It is also possible when using a deep-hole hammer, to have the deep-hole hammer strike immediately on the drill bit shaft 28a.
FIG. 3 illustrates an embodiment in which the impact energy is provided by an external hammer arranged outside the borehole, the impacts being tramitted onto the solid drill bit 28 over the entire length of the inner pipe string 11.
Screwed to an outer thread 55 at the front end of the inner pipe string 11 is a pipe piece 20a that protrudes forward beyond the inner pipe string 11 and which, at its projecting portion, is in engagement with the drill bit shaft 28a via engaging keyings so that the solid drill bit 28 is connected for rotation with the pipe piece 20a, yet is still axially displaceable. The front end face 27 of the pipe piece 20a abuts against the annular collar 29 of the solid drill bit 28. The impacts are transmitted from the impact transmission surface 31 of the annular collar 29 onto the inner impact transmission surface 50 of the annular drill bit 40.
Moreover, the embodiment of FIG. 3 is similar to that of FIGS. 1 and 2. Externally, the device of FIG. 3 looks exactly like the first embodiment so that reference is made to FIG. 1 in that respect.
According to FIG. 3, the pipe piece 20a connected to the inner pipe string 11 forms a guiding for the solid drill bit 28 and a radial support for the tongues 43 of the annular drill bit 40. Thus, the pipe piece 20a bridges an annular space between the inner pipe string 11 or the drill bit shaft 28a and the outer pipe end piece 12, yet it includes longitudinally extending backflush grooves 37 that are aligned with backflush grooves 36 in the annular collar 29. Further, the annular drill bit 28 has a scavenging channel 34 that is continuous in the longitudinal direction and is in communication with the inside of the inner pipe string 11.
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The device comprises a solid drill bit (28) and an annular drill bit (40). Axial impacts are exerted on the solid drill bit (28) which are transmitted onto the annular drill bit (40) through impact transmission surfaces. The annular drill bit (40) is freely axially displaceable within limits. It has rearwardly projecting tongues (43) that engage windows (15) of an outer pipe end piece (12). Thus, the movability of the annular drill bit (40) is ensured without any keyings or the like being necessary, which entail the risk of a clogging with bore material. All movable parts are included in the scavenging so that jamming is avoided.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to douche nozzles for injecting fluids into the female vaginal canal, and more particularly, to a douche nozzle having a specially designed shape, including an enlargement for blocking and dilating the vaginal canal and introducing either a slightly acidic or basic fluid in the canal to coat the canal prior to introduction of sperm into the canal to selectively increase the liklihood of conceiving either a female or male baby.
The question of sex determination of babies prior to conception has excited the curiosity of many persons both in and out of the medical profession over the years. Many techniques for achieving selective conception of a boy or girl baby have been advanced, most of which have proved to be of doubtful reliability. It has been reported in scientific literature that the sex of a baby can be predetermined at, or for as long as a few hours before conception, by inserting slightly basic and acidic solutions into the vaginal canal prior to injection of the sperm. For example, it is known that injection of an alkaline solution into the vaginal canal at or prior to ovulation and fertilization favors conception of a male child. Conversely, use of a slightly acidic douche under the same circumstances favors conception of a female baby. This selectivity in conception occurs since the movement of gynosperm containing the XX or female chromosones in the vaginal canal is inhibited by the presence of a basic or alkaline material, while movement of the androsperm containing the XY or male chromosones is inhibited by the presence of an acidic condition in the canal. Accordingly, it has been found that use of a weak bicarbonate of soda solution douche at or near ovulation greatly favors conception of a male child, while injection of a weak vinegar solution into the vaginal canal favors conception of a female baby.
It has been found that the vehicle or device for effecting insertion of the acidic or basic solution is of primary importance in effecting the desired choice of sex. While conventional douche nozzles may on occasion facilitate the desired choice, the configuration and design of the nozzle used must be carefully considered in order to maximize the chance of success in the procedure.
2. Description of the Prior Art
Many douche nozzles and vaginal syringes for effecting feminine hygiene are well known in the prior art. U.S. Pat. No. 2,888,925 to B. M. Philips is typical of these devices, and discloses a vaginal syringe apparatus which is shaped to block the vaginal canal during use, and to selectively permit fluid to flow into and out of the canal by means of a nozzle and a finger-operated nipple, respectively. The device is connected to a bag containing douche solution, and is fed by gravity, in conventional fashion.
Another device styled "Means for Facilitating Internal Flushing of Syringing" is described in U.S. Pat. No. 766,069 to J. D. Sourwine. The syringing device includes a shaped nozzle for injecting fluids into the vaginal canal during the douching operation.
As heretofore described, a key factor in effecting choice of sex during conception has been found to be the introduction of either a basic or an acidic douche solution into the vaginal canal during ovulation in such a manner as to block the canal, and subsequently coat the canal to effect contact between the solution and sperm subsequently entering the canal. Since the walls of the female vaginal canal are wrinkled and undulate, the device used to effect insertion of the fluid of choice must stretch the vaginal canal wall to smooth the wrinkles, block the canal at the correct point, and facilitate the introduction of fluid in a manner designed to thoroughly coat the vaginal canal walls.
Accordingly, it is an object of this invention to provide a new and improved douche nozzle having a round base which tapers to a round, slender neck and subsequently expands to a bulbous enlargement having multiple openings, and again tapers symmetrically to a discharge opening.
Another object of the invention is to provide a new and improved douche nozzle for insertion in, blocking and stretching the vaginal canal during ovulation and at or near conception, and introducing a quantity of acidic or basic douche fluid into the vaginal canal to thoroughly coat the walls thereof and selectively enhance the liklihood of conception of a female or male baby.
Yet another object of this invention is to provide a hollow douche nozzle device having a round base which is flat on one side and tapers to a slender, round neck on the other side, and subsequently flares to define a bulbous enlargement having multiple apertures communicating with the hollow interior of the device, and further comprising a tapering funnel extending from the enlargement to an opening in the end of the device opposite the round base, which opening and apertures are sized to facilitate a larger volume of flow through the opening than through the apertures.
A still further object of the invention is to provide a hollow douche nozzle for use in selecting the sex of a child, which nozzle is characterized by a generally round base flat on one side, and provided with a check valve and opening extending into the hollow interior, the opposite side of the base tapering to a narrow neck which flares to define a bulbous enlargement having multiple openings communicating with the hollow interior of the nozzle, and the bulbous enlargement further tapering to define an opening in the extended end of the nozzle.
Yet another object of this invention is to provide a specially designed douche nozzle for use in determining the sex of a baby during ovulation and at or prior to conception, and a process for selectively introducing either a basic or an acidic solution into the female vaginal canal by means of the douche nozzle to coat the canal lining and increase the liklihood of conception of a male or female child.
SUMMARY OF THE INVENTION
A douche nozzle designed to stretch and block the female vaginal canal, and a process for using the douche nozzle to selectively introduce a fluid having a PH of greater than 7 or less than 7 into the vaginal canal during ovulation and at or near the time of conception for the purpose of increasing the liklihood of conceiving a boy or a girl baby, which nozzle is hollow and is characterized by a generally round base having a flat surface on one side, a ball check and opening mounted on the flat surface of the base, with the opening extending through the base and communicating with the hollow interior of the nozzle, and a nipple spaced from the ball check and having a like opening, the opposite side of the nozzle base tapering opposite the flat surface to define a narrow, round neck, and shaped to form a bulbous plug or enlargement having multiple openings communicating with the hollow interior of the nozzle, the enlargement then tapering to a central opening in the nozzle at a point spaced from and opposite the ball check opening. A tube connects the ball check opening with a conventional bag designed to contain a quantity of douche solution.
BRIEF DESCRIPTION OF THE DRAWING
The invention will be better understood by reference to the accompanying drawing, wherein:
FIG. 1 is a perspective view of the douche nozzle of this invention;
FIG. 2 is a sectional view, taken along lines 2--2 of the nozzle illustrated in FIG. 1;
FIG. 3 is a front elevation of the nozzle illustrated in FIG. 1;
FIG. 4 is a rear elevation of the nozzle and
FIG. 5 is a perspective view of the nozzle illustrated in FIG. 1 in functional position attached to a bag containing douche solution.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIGS. 1, 3 and 5 of the drawing the douche nozzle of this invention is generally illustrated by reference numeral 1, and is hollow and shaped to define a generally round nozzle base 2, which is flat on one side and tapers on the opposite side to form a narrow, round and symmetrical neck 3. The neck 3 is further tapered outwardly to define a round, bulbous enlargement 4, having a plurality of enlargement apertures 5, which extend through the wall of douche nozzle 1 to communicate with the hollow interior 19, illustrated in FIG. 2. The enlargement 4 is then tapered forwardly of the neck 3 to further define a nozzle aperture 6 in the extreme end of douche nozzle 1, spaced from nozzle base 2. As illustrated in FIG. 5 of the drawing, a length of tubing 15 connects douche nozzle 1 with a conventional bag 17, which is designed to contain douche solution and feed the solution by gravity through tubing 15 and into douche nozzle 1. Bag 17 is fitted with a bag tab 18 for suspending the bag at a level above the douche nozzle 1, and a clip 16 serves to regulate the flow of douche solution from bag 17 into douche nozzle 1.
Referring now to FIGS. 2 and 4 of the drawing, in a preferred embodiment of the invention a ball check, generally illustrated by reference numeral 7, is provided in the center of nozzle base 2, and defines a ball chamber 8, fitted with a ball seat 9 at the upstream end of the chamber to facilitate sealing of ball check nipple 12 by ball 11 if fluid should reverse its flow from the normal direction of flow into douche nozzle 1 indicated by the arrow. A ball cage 10 is fitted to the opposite, or downstream end of ball chamber 8 to permit unobstructed flow of douche fluid through ball chamber 8 and into the hollow interior 19 of douche nozzle 1. A nozzle base nipple 13 is also provided in nozzle base 2, with the nipple aperture 14 communicating with hollow interior 19 of douche nozzle 1, and a nipple cap 20 secured to nozzle base nipple 13 and designed to removably cover the end of the nozzle.
It will be appreciated by those skilled in the art that the douche nozzle of this invention may be constructed from substantially any material known to those skilled in the art to form a smooth, firm outer surface. Accordingly, such materials as ceramics, hard rubber, plastic and fiberglass, in nonexclusive particular, can be used to shape the nozzle. Furthermore, the nozzle can be constructed in various sizes, although it is important that the ratio of the inside diameter of nozzle aperture 6 to the internal diameter of enlargement 4 be kept constant. For example, in a preferred embodiment of the invention, and for most applications, an acceptable inside diameter of nozzle aperture 6 is about 1/4 of an inch, and the internal diameter of the nozzle enlargement 4 is about 13/4 inches. Accordingly, a preferred ratio of inside nozzle aperture diameter to the internal enlargement diameter is about 1:7. This ratio is important, since the flow of douche fluid from bag 17 into douche nozzle 1 must not only flow through nozzle aperture 6, but the fluid pressure in hollow interior 19 must be sufficiently great to force fluid uniformly through enlargement apertures 5. In a most preferred embodiment, this flow of fluid is greater through nozzle aperture 6 than through enlargement apertures 5. In another preferred embodiment of the invention, enlargement apertures 5 are about 1/16 of an inch in diameter, and from about 15 to about 40 apertures are provided in enlargement 4 on about a 3/8 inch spacing. In a most preferred embodiment of the invention the diameter of nozzle aperture 6 is 1/4 of an inch; the internal diameter of nozzle enlargement 4 is about 13/4 inches; the internal diameter of neck 3 is about 3/4 of an inch; the diameter of enlargement apertures 5 is about 1/16 of an inch; and 25 enlargement apertures are provided in enlargement 4.
Referring now to FIGS. 2 and 5 of the drawing, in use, the douche nozzle 1 of this invention is first attached to one end of tubing 15, which end is fitted tightly on ball check nipple 12. The opposite end of tubing 15 is attached to the bottom or drain of bag 17, and bag 17 is suitably elevated and secured above douche nozzle 1 by means of bag tab 18. Clip 16 is secured to tubing 15, and the douche apparatus is ready for use. A weak solution of either bicarbonate of soda or vinegar, depending upon the sex selection made, is then prepared by mixing four teaspoons of bicarbonate of soda to one quart of water, or four teaspoons of vinegar in one quart of water, and the solution of choice is thoroughly mixed and poured into bag 17. The douche nozzle 1 is then inserted into the vaginal canal and clip 16 is removed from tubing 15 or adjusted to allow the douche fluid to flow from the bag into hollow interior 19 of douche nozzle 1. A finger or nipple cap 20 is initially placed over the projecting end of nozzle base nipple 13 to prevent fluid from prematurely exiting douche nozzle 1 after air in the hollow interior 19 of douche nozzle 1 is expelled by displacement of the fluid. When the nozzle fills with fluid, the solution flows through nozzle aperture 6 and enlargement apertures 5 to coat the vaginal canal, and when a predetermined quantity of fluid has flowed into the vaginal canal, the finger or nipple cap 20 is removed from the end of nozzle base nipple 13 and fluid is allowed to flush from the vaginal canal and exit douche nozzle 1 by means of nipple aperture 14. Nipple cap 20 is particularly useful to free both hands of the user to squeeze bag 17 in order to increase the flow rate of the solution through douche nozzle 1, and to increase the fluid pressure inside hollow interior 19 for better distribution of fluid through enlargement apertures 5.
It will be appreciated by those skilled in the art that a very important feature of this invention is the design and configuration of the douche nozzle 1. The exterior surface configuration is shaped to first block the vaginal canal, and then coat the canal with a selected solution for contact with the sperm, which are subsequently introduced into the canal. The inner surface of the vaginal canal is stretched and exposed to the solution by action of the enlargement 4, and the fluid solution is prevented from exiting the canal by nozzle base 2. The annulus created in the vaginal canal by neck 3 serves to permit fluid to more freely flow from apertures 5.
It will be further appreciated that for best results the device should be used before the injection of sperm into the vaginal canal and near the time of ovulation and conception in order that the desired interaction between the sperm and solution may occur to achieve the desired selective conception.
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A douche nozzle for expanding the vaginal canal and contacting the walls of the canal with either a slightly acidic or basic solution before sperm injection and during ovulation for the purpose of increasing the likelihood of selectively conceiving either a female or male baby. A process for selectively conceiving a male or female baby by injecting the appropriate solution into the vaginal canal using the douche nozzle of this invention.
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CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation, under 35 U.S.C. § 120, of copending international application No. PCT/EP03/01502, filed Feb. 14, 2003, which designated the United States; this application also claims the priority, under 35 U.S.C. § 119, of German patent application No. 102 08 472.6, filed Feb. 27, 2002; the prior applications are herewith incorporated by reference in their entirety.
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
[0002] The present invention is concerned with a household appliance having a useful space, which can be closed by a door, and a storage space, which is disposed below the useful space and into which the store can be displaced. The door is associated with a guide system having at least one slotted-guide track, by which the door is guided during a movement from a closed position to the storage space.
[0003] German Published, Non-Prosecuted Patent Application DE 199 06 913 discloses a generic household appliance having a door that closes a useful space in the household appliance. Below the useful space, an opening having a guide system disposed in it is formed in a horizontal plane. The door can be slid into the opening through the guide system.
SUMMARY OF THE INVENTION
[0004] It is accordingly an object of the invention to provide a household appliance that overcomes the hereinafore-mentioned disadvantages of the heretofore-known devices of this general type and that has an enlarged useful space while the overall size remains the same.
[0005] With the foregoing and other objects in view, there is provided, in accordance with the invention, a household appliance, includes a housing defining a useful space and a door opening, a door pivotally connected to the housing and selectively closing off the door opening in a closed position thereof, the door having a guide element, a storage space disposed below the useful space and the door is displaced selectively into the storage space, and a guide system having at least one slotted-guide track in which the guide element is guided during a movement of the door from the closed position into the storage space, the slotted-guide track having a starting section initially guiding the door upward during a movement from the closed position.
[0006] The slotted-guide track has a starting section that initially guides the door upward during a movement from its closed position. By such a lifting movement, a lower edge of the door, which edge pivots into the storage space, is initially displaced upward. During the movement of the door into this storage space, the lower edge of the door, therefore, describes a pivoting region that is spaced apart from a base of the storage space and does not intersect the plane of the base. The movement of the door into the storage space, therefore, requires an extremely low storage-space height. The low storage-space height advantageously enables the useful space to be enlarged without changing the overall size of the household appliance.
[0007] In accordance with another feature of the invention, the angle of ascent of the starting section is 30° to 60° and, in particular, approximately 45°. This, first, results in an ergonomically favorable door movement for an operator. Second, at the same time as the movement according to the invention upward, the door already can be executing a pivoting movement. The lifting movement of the door is, therefore, not restricted by an upper door boundary, for example, an upper edge strip.
[0008] In accordance with a further feature of the invention, to achieve an ergonomically favorable and harmonic movement of the door, the starting section of the slotted-guide track merges into a substantially horizontal slide-in section, in which the door is guided into the storage space in a substantially horizontal plane.
[0009] In accordance with an added feature of the invention, a space divider is disposed in a region of the storage space below the slotted-guide track. The space divider divides the storage space into a first storage space, in which the door and the guide system are disposed, and into a second storage space. In the second storage space, baking sheets or other accessories, for example, can be stored. In this slide-in section, the door moves rectilinearly in a plane with the slotted-guide track. As a result, a harmonic movement of the door is obtained and a tilting of the door can be avoided.
[0010] In accordance with an additional feature of the invention, it is particularly advantageous if the starting section is no more than 30% of the entire length of the slotted-guided track. In addition to an ergonomically favorable pivoting profile of the door, such a configuration has the effect that the pivoting region of the lower edge of the door protrudes only slightly into the storage space. The above-mentioned space divider can, therefore, divide advantageously virtually the entire storage space without cutting across the pivoting region of the lower edge of the door.
[0011] In accordance with yet another feature of the invention, the door can be mounted pivotally about a hinge pin, which is fixed on the housing and which is guided displaceably in a guide rail of the door. This results in an advantageous, ergonomically favorable movement of the door for the operator. In addition, the structural outlay on the movement of the door into the storage space is reduced by the realization of the pivot pin in a manner fixed on the housing because a moving hinge pin and associated moving guide track can be avoided.
[0012] In accordance with yet a further feature of the invention, it is advantageous if the hinge pin, which is fixed on the housing, is disposed level with the slide-in section of the slotted-guide track. A pivoting movement of the door, therefore, takes place only if the guide element runs in the starting section of the slotted-guide track. When the guide element runs in the region of the slide-in section, the guide element is already in its horizontal position.
[0013] In accordance with a concomitant feature of the invention, the invention is not restricted to a configuration of the storage space below the useful space. On the contrary, the storage space may also be disposed at the side of or above the useful space.
[0014] Other features that are considered as characteristic for the invention are set forth in the appended claims.
[0015] Although the invention is illustrated and described herein as embodied in a household appliance, it is, nevertheless, not intended to be limited to the details shown because various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
[0016] The construction and method of operation of the invention, however, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 is a perspective front view of a first exemplary embodiment of a cooking appliance according to the invention with an opened door;
[0018] FIG. 2 is a fragmentary, enlarged perspective and partially hidden view of a cutout of a door handle according to the invention with an associated bearing housing;
[0019] FIG. 3 is a fragmentary, side cross-sectional view of the handle of FIG. 2 along section line A-A;
[0020] FIG. 4 is a fragmentary, side cross-sectional view of the door handle of FIG. 1 along section line B-B;
[0021] FIG. 5 is a diagrammatic, enlarged, cross-sectional view of a detail of the handle of FIG. 4 ;
[0022] FIG. 6 is a fragmentary, perspective and partially hidden view of a second exemplary embodiment of a cooking appliance according to the invention;
[0023] FIG. 7 is a fragmentary, perspective and partially hidden view of a storage space module of the cooking appliance of FIG. 6 ;
[0024] FIG. 8 is a fragmentary, enlarged, perspective view of a detail of the module of FIG. 7 ;
[0025] FIG. 9A is a fragmentary, side elevational and partially hidden view of a first part of an opening process of the mechanism of FIG. 8 ;
[0026] FIG. 9B is a fragmentary, side elevational and partially hidden view of a second part of an opening process of the mechanism of FIG. 8 ;
[0027] FIG. 9C is a fragmentary, side elevational and partially hidden view of a third part of an opening process of the mechanism of FIG. 8 ;
[0028] FIG. 10 shows a side sectional illustration of an upper and lower section of the door of the cooking appliance from FIG. 6 ;
[0029] FIG. 11 is a side elevational view of the mechanisms of FIGS. 7 and 8 along line D-D in FIG. 7 in a first position;
[0030] FIG. 12 is a side elevational view of the mechanism of FIG. 11 in a second position;
[0031] FIG. 13A is a schematic front elevational view of a variant of the household appliance according to the invention with the storage space module on the bottom thereof;
[0032] FIG. 13B is a schematic front elevational view of a further variant of the household appliance according to the invention with the storage space module on the top thereof; and
[0033] FIG. 13C is a schematic front elevational view of another variant of the household appliance according to the invention with the storage space module on the side thereof.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0034] Referring now to the figures of the drawings in detail and first, particularly to FIG. 1 thereof, there is shown a cooking appliance 1 in a first exemplary embodiment of a household appliance according to the invention. The cooking appliance 1 has front-side operating and display elements 2 with an associated non-illustrated control unit. Furthermore, a cooking space 3 is provided in the cooking appliance 1 . The cooking space 3 is bounded by a muffle 4 that is open on the front side. A front-side muffle frame 8 frames the front-side opening of the muffle 4 . The cooking space 3 can be closed by a door 5 that is mounted pivotally about a horizontal hinge pin or articulation axis 12 . The door 5 has an inner door window 7 and an outer door window 9 of glass or glass ceramic. A door handle 17 , which is mounted pivotally in a bearing housing 21 , is provided on an upper end side 6 of the door 5 .
[0035] FIG. 2 shows the configuration including the door handle 17 and the bearing housing 21 in a perspective illustration enlarged in some sections. For simplification purposes, the inner and outer door windows 7 , 9 of the door are omitted. The door handle 17 has a handle strip 13 that is connected to a pivoting part 16 through bearing blocks 15 . The pivoting part 16 forms the upper end side 6 of the door 5 and has pivot pins 19 on both sides in the longitudinal direction. The pivot pins 19 are mounted rotatably in the bearing housing 21 . Both the bearing housing 21 and the pivoting part 16 are, preferably, manufactured as an injection molded part from a duroplastic (thermosetting plastic material). Stiffening elements 23 are formed on both longitudinal sides of the bearing housing 21 . These stiffening elements 23 dip into an inner space 41 of the door and are fastened releasably, for example, screwed, to lateral edge strips 25 of the door 5 .
[0036] Additional stiffening elements 27 are formed on the front side of the bearing housing 21 . According to FIG. 3 , the stiffening elements 27 are in contact with the outer door window 9 . FIG. 3 shows a sectional illustration along the line A-A from FIG. 2 , in which the door windows 7 , 9 are indicated in dashed lines. Accordingly, the stiffening element 27 is in contact with the outer door window 9 while the inner door window 7 rests, with the interposition of a seal 29 , against a contact surface 22 of the bearing housing 21 . FIG. 3 , furthermore, reveals that the bearing housing 21 has a supporting surface 31 . The supporting surface 31 is disposed between the lateral pivot pins (journals) 19 and extends in the axial direction of the pivoting part 16 over virtually the entire length of the pivoting part 1 . A corresponding mating surface 33 of the pivoting part 16 is in contact with the supporting surface 31 . During the pivoting movement of the door handle 17 , the pivoting part 16 thereof is, therefore, supported on the supporting surface 31 . Furthermore, two stops 35 , 37 that restrict and bound a pivoting region of the door handle 17 are formed on the bearing housing 21 .
[0037] As illustrated in FIG. 2 , the door handle 17 is assigned a tension spring 39 that pre-stresses the door handle 17 in a pivoting direction. The tension spring 39 is provided below the bearing housing 21 and extends in the longitudinal direction of the bearing housing 21 . The tension spring 39 is suspended freely in the inner space 41 of the door that is formed between the door windows 7 , 9 . The freely suspended configuration of the tension spring 39 within the inner space 41 of the door makes it possible to achieve a free expansion and, therefore, low-wear loading of the tension spring 39 .
[0038] The two ends of the tension spring 39 are connected in each case through a first tension cable 43 to the pivoting part 16 to transmit a tension spring force to the pivoting part 16 . The first tension cables 43 are guided through deflecting rollers 45 , which are mounted rotatably on the stiffening elements 27 , to radial cam plates 47 . The radial cams 47 are connected on both sides in a rotationally fixed manner to the longitudinal ends of the pivoting part 16 . Each of the first pulling cables 43 here is fixed on the circumference of the cam plate 47 at a fastening point 46 . As a result, the tension spring 39 pre-stresses the door handle 17 against the first stop 35 and subjects the door handle 17 to a first torque M 1 in a pivoting direction ( FIG. 4 ). To protect against contamination, the radial cams 47 are disposed within lateral cutouts of the pivoting part 16 . Covering sections 18 of the pivoting part 16 cover the cutouts on the end side.
[0039] A second tension cable 48 engages on the circumference of each of the radial cams 47 . The second tension cable 48 is guided around the cam plate 47 in the direction counter to the first pulling cable 43 and is fixed on the circumference of the cam plate 47 at the fastening point 46 . The first and second tension cables 43 , 48 and the radial cams 47 form constituent parts of a control mechanism 38 . The control mechanism 38 transmits a pivoting movement of the door 5 to the door handle 17 , i.e., when the door 5 is pivoted in a first pivoting direction, the control mechanism 38 pivots the door handle 17 in a second pivoting direction, counter to the first pivoting direction. The construction and functioning of the control mechanism 38 are explained below with reference to FIG. 4 .
[0040] FIG. 4 shows an upper and lower cutout of the door 5 in a sectional illustration along the line B-B from FIG. 1 . The door 5 is disposed in a closed position. A driving drum 54 that serves as a driving part of the control mechanism is disposed in the lower section of the door 5 . Starting from the driving drum 54 , a rotational movement is transmitted through the tension cable 48 to the radial cam 47 . The tension cable 48 engages on the circumference of the radial cam 47 . The tension cable 48 , therefore, converts the rotational movement of the driving drum 54 into a rotational movement of the radial cam 47 .
[0041] If the door 5 is pivoted downward from its closed position, which is shown in FIG. 4 , the driving drum 54 rotates. The introduction of movement into the driving drum 54 is described later on with reference to the second exemplary embodiment. The rotational movement of the driving drum 54 is transmitted through the tension cable 48 to the radial cam 47 . As a result, a second torque M 2 , which is directed counter to the first torque M 1 , is exerted on the door handle 17 . The effect that can be achieved as a result is that the horizontal alignment of the door handle 17 that is shown in FIG. 4 is substantially retained regardless of the pivoting position of the door 5 .
[0042] If an operator exerts an upwardly directed actuating force F on the door handle 17 shown in FIG. 4 —for example, during transportation of the cooking appliance—the resultant pivoting movement of the pivoting part 16 of the door handle in the clockwise direction is absorbed by the tension spring 39 . This prevents the pivoting movement of the door handle 17 , which movement is directed in the clockwise direction of FIG. 4 , from being transmitted to the control mechanism 38 . The tension spring 39 , accordingly, acts, as a safeguarding device that prevents damage to the control mechanism 38 .
[0043] The magnitude of the spring force of the tension spring 39 and/or the torque M 1 exerted thereby is based on a minimum value for the spring force of the tension spring 39 . This minimum value corresponds approximately to the frictional forces that have to be overcome to restore the door handle 17 after an actuating force F is no longer exerted on the door handle 17 . The tension spring 39 is dimensioned such that the abovementioned minimum value is approximately 10% to 20% of the spring force of the tension spring 39 . The spring force of the tension spring 39 is, therefore, approximately five to ten times larger than this minimum value. When the door handle 17 is actuated incorrectly, for example, as a result of the upwardly directed actuating force F being exerted (see FIG. 4 ), damage to the control mechanism 38 is, thus, prevented. At the same time, the comparatively large spring force permits an ergonomically favorable operating feel during a normal opening or closing actuation of the door handle 17 by the operator.
[0044] The radius of the cam plate 47 is very important to ensure that the movement of the hinge rod 55 is transmitted to the door handle 17 in a correct transmission ratio. On one hand, the radius of the cam plate 47 determines the length of the lever arm and, thus, the magnitude of the torque by which the pulling cables 43 , 48 act on the cam plate 47 . On the other hand, the cam-plate radius defines the transmission ratio by which a drive movement of the control mechanism 38 is converted into a pivoting movement of the door handle 17 . In FIG. 5 , the lever-arm lengths r 1 , r 2 of the cam plate 47 , which lengths are associated with the first and the second tension cable 43 , 48 , are configured such that they differ in magnitude. FIG. 5 shows an enlarged illustration of the radial cam 47 from FIG. 4 .
[0045] In FIG. 5 , the points of action of the pulling cables 43 and 48 are designated A 1 and A 2 . During an operation for opening the door 5 , the point of action A 1 of the pulling cable 43 moves through an angle of rotation of approximately 90° in the counterclockwise direction along the circumference of the cam plate 47 . Over this angle of rotation, the lever arm length r 1 is substantially constant. The torque M 1 exerted on the door handle 17 is, therefore, constant during the pivoting movement of the door 5 . At the same time, the engagement point A 2 of the tension cable 48 moves through an angle of rotation section of approximately 90° in the counter-clockwise direction (with respect to FIG. 5 ) along the circumference of the radial cam 47 . Over this angle of rotation, the lever arm length r 2 is reduced during a pivoting movement of the door 5 from its closed position; that is to say, in the horizontal door position, the torque M 2 exerted on the door handle 17 is the lowest possible. In the horizontal door position, the torque M 2 counteracts a weight of the door 5 ; the weight of the door 5 keeps the door 5 stably in its horizontal position. The torque M 2 , which is reduced in the horizontal door position, is, therefore, not capable of compensating for the weight of the door. The stable position of the door in its horizontal position is, therefore, not adversely affected by the torque M 2 .
[0046] A radial cam 47 that is formed eccentrically enables the transmission ratio of the control mechanism 38 to be changed as a function of the pivoting position of the door 5 . It is thus possible to compensate for drive losses of the control mechanism 38 , which are produced, for example, at the beginning of a pivoting movement of the door as a result of expansion of the pulling cables 43 , 48 or of play in the control mechanism 38 .
[0047] FIG. 6 shows a cooking appliance according to a second exemplary embodiment of the present invention. The cooking appliance has a useful space module 83 , which is indicated by a chain-dotted line and in which the cooking appliance muffle 3 (not illustrated) is disposed. A storage space module 79 is disposed below the useful space module 83 . The storage space module 79 has a storage space 61 in which a guide system 58 for the door 5 is provided. The guide system 58 enables the cooking appliance door 5 (illustrated by dashed lines) to be displaced into the storage space module 79 . According to FIG. 6 , the storage space module 79 serves as a base or foundation on which the useful space module 83 is mounted. The storage space module 79 is configured as an upwardly open sheet-metal housing. Step-shaped abutment shoulders 85 are formed on the upper edge of the side walls 80 of the sheet-metal housing 79 . The useful space module 83 rests on the contact shoulders 85 in a positionally correct manner, as indicated in FIG. 6 . The operating and display elements 2 , which are shown in FIG. 1 , and an associated control unit are provided in the useful space module 83 . The operating and display elements 2 , here, together with the associated control unit, can function independently of the stowage-space module 79 .
[0048] The control mechanism 38 of the second exemplary embodiment has, as driving part, a rotary shaft 57 on which the driving drum 54 , which is already mentioned in the first exemplary embodiment, is formed. The rotary shaft 57 is operatively connected to a guide element 59 of the guide system 58 .
[0049] The construction and the manner of operation of the guide system 58 for the door 5 and the production of a driving movement for the control mechanism 38 are explained below.
[0050] As illustrated in FIG. 6 , the guide element 59 is part of the guide system 58 , with the aid of which the door 5 is pushed, during an opening process, into the storage space 61 provided below the cooking space 3 . FIGS. 6 and 7 reveal that the guide system 58 has slotted-guide tracks 63 . The slotted-guide tracks 63 are formed in the two opposite side walls 80 of the storage space module 79 . The opposite slotted-guide tracks 63 guide sliders 60 of the guide element 59 therein. The sliders 60 are welded to each other through a connecting rod 62 . The guide element 59 is, therefore, guided in the opposite slotted-guide tracks 63 in the manner of a guide carriage. Between the two sliders 60 , adjusting levers 67 are welded to the connecting rod 62 . As illustrated in the enlarged perspective cutout of FIG. 8 , the adjusting levers 67 are connected in a form-fitting manner to the rotary shaft 57 of the control mechanism 58 . The rotary shaft 57 is indicated in FIGS. 6 and 7 by chain-dotted lines.
[0051] The above-mentioned form-fitting connection between the adjusting levers 67 of the guide carriage 59 and the rotary shaft 57 of the door 5 is illustrated in FIG. 8 . The inner and outer door windows 7 , 9 of the door 5 have been omitted from FIG. 8 . Accordingly, the rotary shaft 57 is mounted rotatably in the opposite edge strips 25 of the door 5 . For the form-fitting connection, the adjusting levers 67 of the guide carriage 59 each have a rectangular cutout 69 ( FIG. 8 ). A corresponding, rectangular shape section 71 of the rotary shaft 57 is mounted in the cutout 69 . The lateral edge strips 25 of the door 5 are provided in the outward direction in each case with a U-shaped groove that serves as a guide rail. In these guide rails 25 , respective bearing rollers 65 are guided displaceably on both sides. The bearing rollers 65 are fastened to the side wall 80 of the storage space module 79 . The U-shaped groove, which serves as a guide rail, is constructed on its lower end side with an open end 26 . When the door is removed, as will be described at a later stage in the text, the housing-mounted bearing roller 65 can be released from the associated guide rail 25 by way of the open end 26 .
[0052] Each of the opposite slotted-guide tracks 63 has a starting section 90 and a slide-in section 91 . According to FIGS. 9A and 9C , an angle of inclination of the starting section 90 is approximately 45°. The starting section 90 , furthermore, takes up approximately 30% of the entire length of the slotted-guide track 63 while the transition between the starting section 90 and the slide-in section 91 has a curved profile. The slide-in section 91 runs substantially in a horizontal plane. The bearing rollers 65 , which are fixed on the housing, are disposed approximately level with the slide-in section 91 of the slotted-guide track 63 .
[0053] The course of movement of the guide carriage 59 of the door 5 in the slotted-guide tracks 63 is described with reference to FIGS. 9A to 9 C. FIG. 9A shows the door 5 in its closed position. In the closed position, the sliders 60 of the guide carriage 59 are in the starting section 90 of the slotted-guide track 63 . During an opening movement of the door 5 from its closed position shown in FIG. 10 , the sliders 60 of the guide carriage 59 are initially displaced upward. As a result, the adjusting levers 67 of the guide carriage 59 lift the door 5 upward. With this lifting movement of the door 5 , a lower end side 93 of the door 5 , which side pivots into the storage space 61 , is displaced, at the same time, upward away from a base 117 of the storage space module 79 , as is revealed in FIG. 9B . As a result, a pivoting region S of the lower end side 93 , which region protrudes into the storage space 61 and is indicated by a chain-dotted line, is reduced. After the guide carriage 59 is moved from the starting section 90 into the horizontal slide-in section 91 ( FIG. 9C ), the door 5 is in a horizontal plane, in which it can be slid into the storage space 61 . During the pivoting movement of the door 5 , a pivoting angle between the door 5 and the guide block 59 changes. Because the rotary shaft 57 of the control mechanism 38 is mounted in a form-fitting manner in the adjusting levers 67 of the guide slide 59 , the change in the pivoting angle between the door 5 and the guide carriage 59 causes a rotation of the rotary shaft 57 . That is to say, during the pivoting movement of the door 5 , the rotary shaft 57 is inevitably rotated by the guide element 59 .
[0054] The manner in which the control mechanism 38 transmits the inevitable rotation of the rotary shaft 57 to the door handle 17 is explained with reference to FIG. 10 . FIG. 10 shows a side sectional view of the upper and lower section of the door 5 according to the second exemplary embodiment. This reveals that the adjusting lever 67 protrudes through an access opening 129 of the door 5 into the interior space 41 of the door and is connected in a form-fitting manner to the rotary shaft 57 . As can be gathered from FIGS. 8 and 10 , the rotary shaft 57 is configured with a driving drum 54 , which is disposed in a rotationally fixed manner on the rotary shaft 57 . The driving drum 54 is in engagement circumferentially with the tension cable 48 . As in the first exemplary embodiment, the tension cable 48 is connected to the door handle 17 .
[0055] During the pivoting movement of the door 5 , a pivoting movement, therefore, arises between the guide carriage 59 and the door 5 . As a result, the rotary shaft 57 is rotated inevitably. The rotational movement of the rotary shaft 57 is transmitted through the driving drum 54 to the tension cable 48 . The tension cable 48 converts the rotational movement of the rotary shaft 57 into a rotational movement of the radial cam 47 and subjects the door handle to the second torque M 2 , which is directed counter to the first torque M 1 , on the door handle 17 . The door handle 17 , therefore, retains its horizontal alignment regardless of the pivoting position of the door 5 .
[0056] In contrast to FIG. 4 of the first exemplary embodiment, in FIG. 10 , the first tension cables 43 , which engage on both sides on the radial cams 47 of the pivoting part 16 of the door handle 17 , are not connected to a common tension spring. Rather, according to FIG. 10 , each of the first tension cables 43 is associated with a dedicated tension spring 39 . The tension spring 39 is fastened at one end of the spring to the edge strip 25 of the door 5 . The other end of the tension spring 39 is coupled to the tension cable 43 through a retaining eyelet 75 . As a result, the door handle 17 is subjected to the first torque M 1 in the counterclockwise direction.
[0057] The control mechanism 38 shown in FIG. 10 has a third tension cable 77 . The third tension cable 77 is, on one hand, in circumferential engagement with the driving drum 54 of the rotary shaft 57 and is guided about the driving drum 54 in the opposite direction to the second tension cable 48 . On the other hand, the third tension cable 77 is connected to the retaining eyelet 75 of the first tension cable 43 . The first, second, and third tension cables 43 , 48 , 77 of the control mechanism 38 form a closed cable control that envelops the radial cam 47 and the driving drum 54 to transmit the rotational movement to the door handle 17 .
[0058] To tighten the closed cable control 43 , 48 , 77 , a tightening spring 79 is integrated in the third tension cable 77 . The tightening spring 79 serves to tighten the closed cable control 43 , 48 , 77 . In addition, the tightening spring 79 increases the torque M 1 that is exerted by the tension spring 39 on the door handle 17 . Therefore, both the tightening spring 79 and the tension spring 39 are present for exerting the torque M 1 . It is, therefore, advantageously possible for use to be made of two comparatively small springs that take up only a small amount of space in the limited inner space 41 of the door.
[0059] If the operator, for example, during transportation of the cooking appliance 1 , exerts an upwardly directed actuating force F on the door handle 17 shown in FIG. 4 , the resultant pivoting movement of the pivoting part 16 of the door handle in the clockwise direction is absorbed by the tension spring 39 and by the tightening spring 79 . The resultant pivoting movement of the pivoting part 16 is, therefore, not transmitted from the door handle 17 to the control mechanism 38 . As a result, damage to the control mechanism 38 is prevented.
[0060] The dimensioning of the spring force of the tension springs 39 , 79 depend on the minimum value for the spring force, which value is specified in conjunction with FIG. 4 .
[0061] Furthermore, the tension cables 43 , 48 , 77 can be provided with adjusting elements for adjusting a tensile stressing. By the adjusting elements, the tension cables provided on both sides of the door sides can be acted upon with an identical tensile stress. As a result, a synchronous operation of the two control mechanisms 38 is achieved.
[0062] A weight-balancing configuration 94 for the door 5 of the second exemplary embodiment is described below with reference to FIGS. 7, 11 , and 12 . During a movement of the door 5 , the weight-balancing configuration 94 exerts a balancing force on the door 5 , which force acts counter to the weight of the door 5 . The weight of the door 5 is, therefore, not absorbed by the operator during a door movement, but, rather, by the weight-balancing configuration 94 .
[0063] FIG. 7 shows, in a perspective view, the storage space module 79 , of which a space divider 111 (described later on) is illustrated separately. On each of the opposite side walls 80 , the weight-balancing configuration 94 has a pivoting lever 95 . The pivoting lever 95 is mounted pivotally on the opposite side walls 80 through a lever spindle 97 . FIG. 11 shows one of the side walls 80 in an enlarged side elevational view along the line D-D from FIG. 7 . Accordingly, the pivoting lever 95 protrudes into the starting section 90 of the slotted-guide track 63 and is in engagement with the slider 60 of the guide carriage 59 . A pivoting region of the pivoting lever 95 is configured such that the pivoting lever 95 is in engagement with the slider 60 of the guide carriage 59 only in the region of the starting section 90 . By contrast, in the horizontal section 91 , the pivoting lever 95 is disengaged from the slider 60 of the guide carriage 59 . The pivoting lever 95 is connected to a tension spring 103 . The tension spring 103 is fastened to the side wall 80 . In FIG. 11 , the tension spring 103 pre-stresses the pivoting lever 95 in the counter-clockwise direction.
[0064] When the door 5 , which is illustrated by dashed lines in FIG. 11 , is pivoted from its closed position downward into the horizontal position, the slider 60 runs from the starting section 90 into the horizontal section 91 of the slotted-guide track 63 . During this movement, the slider 60 of the guide slide 59 presses against the spring-pre-stressed pivoting lever 95 . The pivoting lever 95 , therefore, subjects the sliding component 60 to a balancing force. The balancing force acts counter to the weight of the door 5 .
[0065] As illustrated in FIG. 11 , the pivoting lever 95 is pressed by the spring 103 against a first end stop 99 , which is formed by a rubber support. In the position shown in FIG. 11 , the pivoting lever 95 permits an initial movement of the slider 60 of the guide carriage 59 out of the closed position of the door 5 . During this initial movement, the slider 60 does not engage with the pivoting lever 95 . According to FIG. 11 , the slider 60 comes into contact with the pivoting lever 95 only at a pivoting angle of the door 5 of approximately 20°. This simplifies the initial movement of the door 5 out of its closed position for the operator. Moreover, the pre-stressed pivoting lever 95 according to FIG. 11 acts as a stop against which the slider 60 of the guide carriage 59 strikes during the opening movement of the door 5 . A certain pivoting position of the door 5 is, thus, signaled to the user. In the present case, this pivoting position corresponds to a removal position (described later on), in which a simple removal of the door 5 from the guide system 58 is made possible.
[0066] Furthermore, the weight-compensating configuration 94 has a pivotally mounted retaining element 105 that is pre-stressed by a spring 106 . During the previously described initial movement of the door 5 , the spring-pre-stressed retaining element 105 presses the slider 60 of the guide carriage 59 in the direction of the pivoting lever 95 . As a result, the door 5 is retained stably in the removal position shown in FIG. 11 .
[0067] FIG. 12 shows the door 5 mounted horizontally and slid into the storage space 61 . The slider 60 of the guide carriage 59 of the door 5 is in the horizontal slide-in section 91 of the slotted-guide track 63 . During the movement of the slider 60 in the region of the slide-in section 91 of the slotted-guide track 63 , the pivoting lever 95 is disengaged from the slider 60 . The pivoting lever 95 , therefore, does not exert any balancing force on the door 5 . While the slider 60 runs in the slide-in section 91 of the slotted-guide track 63 , the pivoting lever 95 is in the clockwise direction, by the spring 103 , against a second end stop 101 , which is, likewise, formed by a rubber support.
[0068] The pivoting lever 95 has a driver 107 . The driver 107 of the pivoting lever 95 protrudes, in FIG. 12 , into the slotted-guide track 63 . According to FIG. 12 , the slider 60 has been displaced from the starting section 90 into the slide-in section 91 of the slotted-guide track 63 . The adjusting lever 95 is pre-stressed against the second end stop 101 and is in a holding position. When the door 5 is displaced out of the storage space 61 , the slider 60 comes into engagement with the driver 107 of the pivoting lever 95 . As a result, the pivoting lever 95 is brought out of its holding position and comes, once again, into a pressure contact with the slider 60 of the guide carriage 59 . As a result, the pivoting lever 95 can, once again, exert the compensating force on the guide carriage 59 during a pivoting movement of the door 5 .
[0069] The releasable mounting of the door 5 on the guide system 58 is explained below with reference to FIG. 8 . Due to the releasable mounting of the door 5 in the guide system 58 , the door 5 can easily be removed for cleaning. As already described with reference to FIG. 8 , the adjusting levers 67 have a rectangular cutout 69 . The corresponding rectangular shape section 71 of the rotary shaft 57 is mounted in the rectangular cutout 69 . This produces a form-fitting connection between the guide carriage 59 and the rotary shaft 57 . A locking element 73 that, according to FIG. 8 , is mounted on the rotary shaft 57 is explained below. The locking element 73 can be displaced between a locking position and a release position. In the release position, the locking element 73 releases the mounting of the rotary shaft 57 in the adjusting lever 67 . In a locking position of the locking element 73 , the rotary shaft 57 is connected non-releasably to the adjusting lever 67 .
[0070] The space divider 111 that is mentioned in conjunction with FIG. 7 is explained in the following text. As emerges, in particular, from FIG. 6 , the space divider 111 is disposed in the storage space module 79 . The space divider 111 divides the storage space 61 into a first storage space 61 a and a second storage space 61 b . The space divider 111 has a horizontal intermediate base 113 and side walls 115 . The door 5 can be displaced into the first storage space 61 a . The space divider 111 also separates the guide system 58 , which is formed from the slotted-guide track 62 and guide carriage 59 , and the weight-balancing configuration 94 from the second storage space 61 b . Baking sheets or other accessories may be stored in the second storage space 61 b.
[0071] As emerges from FIGS. 9A to 9 C, the space divider 111 is disposed below the starting section 90 and the slide-in section 91 of the slotted-guide track 63 . The intermediate base 113 together with the side walls 115 and a housing base 117 form an access opening 119 . The latter is disposed spaced apart from the pivoting region S (indicated by a chain-dotted line) of the lower end side 93 of the door 5 . Display elements 121 ( FIGS. 7 and 8 ) are provided in the region of the access opening 119 of the second storage space 61 b . The display elements 121 are configured as cams or protuberances that are fastened to the base 117 of the storage space 61 . The display elements 121 indicate to the operator a maximum permissible length for objects that can be stored in the second storage space 61 b without protruding into the pivoting region S of the lower end side 93 of the door 5 . Appliance front-side panels 123 are formed on the side walls 115 of the space divider 111 ( FIG. 7 ). The panels 123 serve for concealing the first storage space 61 a from view. In addition, a collecting or drip channel 125 is provided in the housing base 117 , in the region of the appliance front-side access opening 119 , to keep the second storage space 61 b free from contaminants, for example, dripping condensation water.
[0072] FIGS. 13A to 13 C illustrate, schematically, variants of the household appliance according to the invention. According to FIG. 13A , the useful space module 83 and the storage space module 79 are shown separately from each other. The construction and the manner of operation of the two modules 79 , 83 corresponds to that of the preceding figures. The storage space module 79 and the useful space module 83 are manufactured, first of all, independently of each other as separate constructional units. The storage space module 79 and the useful space module 83 are, then, joined together in an assembly step to form the household appliance. According to FIG. 13A , the storage space module 79 serves as a pedestal on which the useful space module 83 is placed in the arrow direction.
[0073] In contrast to FIG. 13A , in FIG. 13B , the storage space module 79 is disposed above the useful space module 83 . The door 5 can, therefore, be displaced upward into the storage space 61 of the storage space module 79 . In FIG. 13C , the storage space module 79 is disposed upended. According to FIG. 13C , the storage space module 79 , which is disposed upended, is fastened to one side of the useful space module 83 . The door 5 can, therefore, be displaced into the storage space 79 , which is disposed at the side of the useful space module 83 .
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A household device includes a useful storage volume that can be closed by a door and a storage compartment disposed below, above, or to the side of the useful storage volume into which the door can be displaced. The door is associated with a guiding system including at least one slide track, wherein a guiding element associated with the door is guided by displacing the door from a closed position and moving it into the storage compartment. The slide track includes a start section that initially guides the door in an upward direction when it moves out of the closed position. Such a configuration has the same size as conventional household device with an increased useful storage volume.
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BACKGROUND OF INVENTION
Various alkaline based solutions have previously been employed to remove scale from metal surfaces. For example, Webster et al., U.S. Pat. No. 2,458,661 discloses a fused molten alkali salt solution for removing oxide scale and the like from metal surfaces resulting from the forming operation. Further, Shoemaker et al., U.S. Pat. No. 3,260,619 discloses a different molten alkali salt solution to overcome certain problems associated with the disclosed solution in the Webster Patent. However, both these patents contemplate the use of a further conventional acidic bath to remove conditioned scale on the metal surface which results from treatment following the molten alkali solution bath. Such acidic baths include, for example, sulfuric acid, hydrochloric acid which may be in the form of sodium chloride added to sulfuric acid, nitric acid, hydrofluoric acid and the like, alone or in combination, maintained at elevated temperatures, for example, in excess of about 100°F (37°C). It is the problems associated with these acid baths which the present invention intends to overcome by the provision of a gluconate caustic mixture. Although gluconate mixtures are generally known for the removal of rust and some ferrous scale, none have been applied in the field of alloy processing following salt bath conditioning.
The paramount problem associated with acidic solutions for removing conditioned scale on metal surfaces is that of solution disposal. First, disposal is expensive due to the substantial tonnage of such acids used in the descaling process. Further, disposal of such solutions adds to the presently ever-growing pollution problem. In addition to the problem of disposal, acidic solutions, even though dilute, tend to attack the metal surface. Such attack not only creates an undesirable effect on the metal surface, but adds to disposal problems because of greater metal loss within the descaling operation. Further, the use of acidic descaling solutions requires that the metal be rinsed following the molten alkali bath, since alkali carryover has a deleterious effect on the acid solution.
Accordingly, it is a primary object of the instant invention to provide a non-acidic solution and method for removing conditioned scale from the surface of various metals.
Another object of this invention is the provision of a descaling solution which does not present a pollution problem upon disposal.
A further object of this invention is providing a solution which is stable, exhibits a good life and rejects metal buildup in the form of a precipitate.
Additionally, it is an object of the present invention to provide a solution which is soluble in water and will offer no particular rinsing problems.
SUMMARY OF THE INVENTION
The present invention relates generally to methods and compositions for removing conditioned scale from metal surfaces. More particularly, the present invention relates to a gluconate triethanolamine, caustic solution and method for removing conditioned scale from metal surfaces following a molten alkali salt bath treatment.
The disclosed method contemplates the primary steps of: first, immersing a metal into a molten salt bath; second, removing the metal from the molten bath and allowing the metal to cool prior to further treatment; and third, immersing the metal in a caustic bath solution to remove surface scale. The caustic bath is a water solution containing a mixture of from about 20 to 95% by weight of an alkali hydroxide and from about 5 to 80% by weight of an alkali gluconate and about 1 to 6% triethanolamine, which serves as a chelating agent. The hydroxyl groups in the gluconate ion are converted to methoxide functions which are extremely effective for sequestering trivalent metal ions acting to dissolve the conditioned scale. The complexing action of the gluconate and triethanolamine further reduces the concentration of metal particles within the solution so that additional metal scale can be dissolved. The mixture, which is preferably in concentrations within the solution from about 2 to 12 lbs. per gallon of water, may further include other compositions such as complexing agents for inorganic salts and alkali catalysts to enhance the cleaning capabilities of the solution.
The method and composition of the present invention may optionally include the maintenance of an electric current on the caustic bath by using the metal to be cleaned as an anode, to even further enhance the cleaning capabilities. Furthermore, a later electrolytic solution and step may optionally be included within cleaning process for removing stubborn scale or film.
The gluconate, caustic mixture and method of the present invention are primarily designed for removing conditioned scale from stainless steel metal products. However, the present invention has also been found to be effective in descaling carbon steel, titanium alloys, some high temperature alloy grades, and cast iron. In the process of removing scale from cast iron, the molten salt bath may include an electrolytic process to remove sand and graphite.
The particular advantages of the present invention satisfy the objects previously enumerated. Specifically, the present solution and method accomplishes a commercially clean metal surface which does not require acid pickling. As a necessary consequence of substituting an alkaline solution for an acid cleaning solution, metal surface attack is eliminated as well as many pollution problems associated with acid disposal. Disposal of the gluconate caustic solution can be accomplished by evaporation to dryness by conversion to harmless carbonate.
DETAILED DESCRIPTION
Consistent with the above objectives and summarized description, it has been found that a caustic water solution containing a material found of the following mixture has all of the desired properties and characteristics:
______________________________________ RANGE, PREFERRED,MATERIAL PER CENT PER CENT BY WEIGHT BY WEIGHT OF MIXTURE OF MIXTURE______________________________________SODIUM HYDROXIDE °- 95 77NaOHSODIUM GLUCONATEHOCH.sub.2 (CHOH).sub.4 COONa 5 - 80 20ETHYLENE-DIAMINE-TETRACETIC ACID(EDTA) 0 - 0.4 0.2SODIUM CHLORIDENaClorSODIUM FLUORIDENaF 0.0 - 1.7 1.7TRIETHANOLAMINE 0 - 6 1.0______________________________________
In addition to the compound set forth in the table above, the mixture may also include traces of other common compounds, such as a wetting agent, an alkali stable organic dye, carbonates, borates, and phosphates. Further, although sodium is the primary alkali described in combination with the various other compounds, other alkali could be used in place of sodium hydroxide. For example, the mixture could consist of potassium hydroxide with a potassium gluconate.
Although each of the materials forming part of the bath of this invention are known in and of themselves for use in the treatment of metals, the particular combination defined hereby and the specific quantitative relationship between the components of the mixture provide a synergistic result not realizable from the individual materials or other combinations. Specifically, sodium hydroxide is commonly used to dissolve the iron oxide scales. However, this constituent is primarily used in molten salt baths of the types previously discussed with regard to the Webster and Shoemaker Patents. In contrast the mixture containing sodium hydroxide forming the present invention is maintained at a temperature of between 200°F. and 240°F. (93° and 116°C) for the specific purpose of removing conditioned scale which has formed on metals subsequent to a prior salt treatment. When in solution, the sodium or other alkali readily dissociates, leaving a hydroxide ion which reacts with the sodium gluconate and triethanolamine complexes to dissolve the surface layer of metal scale on the metal to be cleaned. It is known that a gluconate anion is especially effective as a sequestering agent in alkaline and free caustic soda solutions. However, when gluconate and sodium hydroxide are mixed, its hydroxyl groups are converted to a methoxide group which is extremely effective for sequestering trivalent metal ions. The specific combination set forth in the present invention therefore performs the function of an acid pickling bath without the previously disadvantages associated with an acid solution. It can be seen from the above chart that the preferred percentage of sodium hydroxide is relatively high in order to accomplish the specific purpose of the bath.
The ethylene-diamine-tetracetic acid (hereby referred to as EDTA), a complexing agent for inorganic salts, is maintained in solution for the purpose of complexing salts which may carry over into the caustic solution from the molten salt bath and as preferential chelate for calcium and magnesium in hard water, thus releasing gluconate ion for chelation of iron.
Optionally, sodium chloride or sodium fluoride can be included within the mixture to serve as a brightening catalyst for the metal surfaces.
With regard to the treating methods, the metal to be cleaned is first immersed in a molten salt bath, as more fully described in the Webster and Shoemaker Patents previously discussed, to condition and oxidize furnace oxidation and vitreous coatings remaining on the metals as a result of the formation process. After this elevated temperature salt bath process, the metal is then cooled. Optionally, the metal is then rinsed to remove at least a part of the salt precipitants remaining on the metal from the molten salt bath. However, this rinsing process is not critical when employing the descaling solution of the present invention because carryover of salt precipitants into the alkaline based bath does not create a harmful effect as it would in acid baths. The metal oxides formed on the surface of the metal during heat treatment have now been further oxidized by the molten salt bath and present an unsightly and unacceptable appearance. Therefore, it is necessary to then immerse the metal within the chelated alkali solution forming the present invention in order to dissolve the metal oxides and produce a bright, metallic color. The desired temperature range of this bath is between about 200° and 240°F (93° and 116°C). Further, with concentrations of the mixture previously described ranging from 2 to 12 lbs. per gallon of water, the resulting pH should be within the strongly alkaline range or above 14.
Following the chelated alkali solution, the metal surface should be finally rinsed and scrubbed to remove all of the free alkaline solution as a final step in preparing a commercially acceptable metal surface.
A further optional feature contemplated by the present invention is the inclusion of an electrolytic step at a desired point within the overall process. It should be noted that although the present invention is designed primarily for removing conditioned oxide scale from the surface of continuous stainless steel strip, it can also be employed to remove conditioned scale from other similar materials such as carbon steel, titanium alloys, some high temperature alloy grades, and cast iron. In the case of cast iron, an electrolytic process is combined with the molten alkali bath in order to effectively and completely remove sand and graphite deposited on the metal surface during the forming process.
Further, an electric current may be maintained in the caustic alkali bath forming the present invention, utilizing the metal to be cleaned as an anode, in order to further enhance the cleaning capabilities. In the case of stainless steel, the preferred current density maintained in the caustic alkali bath ranges between 0.001 and 0.1 amps./sq. in. Such an electrolytic process aids in cleaning the metal surfaces because of the scrubbing action due to the oxygen and hydrogen bubbles forming around the metal, which is acting as an anode.
Additionally, certain grades of stainless steel exhibit a tendency to retain a yellowish cast on their surface following the basic steps of the present invention. To remove this yellowish cast or film, the present invention contemplates an additional step of treating the metal in a 2 to 4% sodium bifluoride solution anodically at a current density of about 0.25 amps./sq. in. The desired current density during any of the previously mentioned electrolytic processes may be maintained according to standard practices recognized within the art, for example by using low carbon steel electrodes with a prescribed exposed surface.
To prepare the bath solution of the present invention, it is suggested that a tank be filled with water to about one-third of the final calculated volume. The previously described mixture should then be added slowly while agitating or stirring the water in order to properly dissolve the mixture. Once the mixture has been dissolved, the balance of the water should then be added and then heated to the proper operating temperature. Stainless steel is the preferred construction for treating tanks and agitators. Alternately a carbon steel tank lined with Teflon may be used.
The bath of this invention has been demonstrated to maintain its efficiency over extended periods of time. Of course, small quantities of additional material mixture and water need to be added from time to time to replace losses occurring from dragout of the metal work pieces and evaporation in order to maintain both the volume and desired equilibrium of the bath.
Having described the present inventive concept, the following specific examples will serve to further illustrate the same. However, it should be understood that examples are merely exemplary and not to be interpreted as limiting in any way.
EXAMPLES
To prepare for the examples set forth below, an alkali gluconate pickle bath forming the present invention was prepared to achieve the following approximate composition: 23% sodium hydroxide, 12% sodium gluconate, 0.5% sodium fluoride, 2% triethanolamine, and 62.5% water. The bath was maintained at approximately 220°F. (104°C.) and time cycles were set to coincide with continuous strip pickling. The molten salt bath was maintained at approximately 900°F. (482°C). Small coupons or samples of the various listed grades were first immersed in the molten salt bath, then cooled and water quenched, then pickled in the alkali gluconate bath. It will be noted that Sample 4 was additionally treated in an electrolytic bifluoride solution. This additional step was necessitated for the purpose of removing a very light yellow film remaining on that particular sample of metal after the alkali gluconate bath treatment. That additional electrolytic solution contained approximately 2 to 4% sodium bifluoride, was maintained at approximately 140° to 160°F. (60° to 71° C.), and had a current density of 0.25 amps/sq. in. imposed thereon. It will further be noted that in Sample 5 the alkali gluconate bath is electrolytic to enhance its cleaning capabilities.
__________________________________________________________________________Sample Scale Time Within Time Within ElectrolyticNo. Condition Molten Salt Alkali Gluconate Bifluoride Bath Pickle Bath Solution__________________________________________________________________________1 430 stainless steel 1 minute 1 minute -- annealed for 31/2 minutes at 1475° F (802°C)2 430 stainless steel 1 minute 1 minute -- annealed3 304 hot rolled 1 minute 1 minute -- annealed for 31/2 minutes at 1880° F (1027°C)4 201 stainless steel 30 seconds 1 minute 1 minute annealed for six minutes at 1840°F(1004°C)5 304 hot rolled 1 minute 1 minute -- annealed for 31/2 (electrolytic) minutes at 1880°F(1027°C)__________________________________________________________________________
In each of the above examples, the described process achieved a commercially clean metal sample. Having fully described the present invention, we
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A ferrous metal product to be cleaned is immersed in an oxidizing molten salt bath forming a conditioned scale on the surface of the metal. The conditioned scale is subsequently removed from the metal surface by immersing the metal product in an aqueous caustic bath containing alkali metal hydroxide with alkali gluconate and triethanolamine serving as sequestering agents. The caustic bath may optionally include a brightening catalyst or ethylenediamine-tetracetic acid.
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FIELD OF THE INVENTION
The invention relates to a photoacoustic detector as set forth in the preambles of the appended independent claims, and to a sensor for a photoacoustic detector as well as to a method in the optimization of a door used as a sensor for a photoacoustic detector.
DESCRIPTION OF RELATED ART
When infrared radiation or light in general falls on a gas-filled chamber containing a gas to be analyzed at a partial pressure p x and a carrier gas at a partial pressure p N (often typically nitrogen), radiation will be absorbed by the gas p x . After the absorption process, energy converts to thermal movement at a certain time constant τ (e.g. 10 −5 s). Thus, temperature of the total gas increases by ΔT per unit time. The increase of temperature results also in a pressure increase Δp.
A typical photoacoustic detector comprises a chamber, which is suppliable with a gas to be analyzed, a window for letting modulated or pulsed infrared radiation or light in the chamber, and a pressure sensor adapted to measure pressure variations produced by absorbed infrared radiation or light in the chamber. The pressure sensor comprises typically a microphone, a thin Mylar or metal film. A photoacoustic detector can be used for measuring or detecting infrared radiation in general, but one specific and important application of a detector deals with the measurement and detection of gases or gas mixtures regarding for example air quality and pollution.
In microphones, the movement of a film (Mylar) is usually measured capacitively. The Mylar film is coated with metal and placed in the proximity of another solid metal diaphragm. The result is a capacitor, having a capacitance
C = ɛ r ɛ 0 A h , ( a )
where h represents a distance between the films at rest, A is a surface area of the films, ∈ r ∈ 0 is a dielectric constant for a gas present between the sheets and ∈ 0 the same for a vacuum. The measurement of C provides h which gives the movement of a Mylar film, because
Δ C = - ɛ r ɛ 0 A 3 h 2 Δ h , ( b )
where Δh is a change of distance in the middle and Δh/3 is an average change of distance. Further
Δ C C = - Δ h h
or ( c ) Δ h min ≈ h C / Δ C = h S / N , ( d )
where S/N is a signal-to-noise ratio in measuring electronics.
Capacity measurements of the prior art are limited by a gas flow present between the sheets, as h changes. As the gap h decreases, the gas is forced to flow out from between the sheets and return when h is increasing. The flow has inertia and that requires energy. A result of this is that, the higher the angular oscillation frequency ω of a diaphragm and the smaller h, the more the flow decreases the amplitude of a diaphragm movement. Thus, h cannot be decreased infinitely, as this would augment a signal ΔC. Therefore, the commercially available microphones function at the limits of physical laws and their responsivity cannot be improved in that regard.
In their publication [1], Nicolas Lederman et al. disclose a photoacoustic detector for a sensor, wherein the sensor is fabricated from a cantilever type film, which responses to the movement of a gas in the chamber of a photoacoustic detector and in which film is integrated a piezoelectric element registering the cantilever movement. A problem with the sensor set forth in the publication is that the cantilever's resonance frequency has been omitted. It is likely that a piezoelectric element attached to a sensor increases the sensor's resonance frequency and thus deteriorates the sensor's response. The sensor presented in the publication is quite inaccurate and, therefore, not suitable for high precision applications. Neither does the publication say anything about optimization of a chamber and a sensor in the photoacoustic detector, i.e. the ratio of the size of a chamber to that of a sensor.
In their publications [2] and [3], M. H. de Paula et al. also disclose an alternative to a traditional diaphragm solution. The publications propose that a pellicle be fitted over a small duct in a photoacoustic detector cell at a distance of about 0.1 mm from the duct. According to what is stated in the publication, the pellicle is not provided with a so-called rim around itself, the pellicle thus extending beyond the duct boundaries, i.e. the question is not about a cantilever like the one shown in publication [1]. Hence, the fundamental problem in the publications of de Paula et al. is indeed the fact that the pressure to be measured and existing in a photoacoustic detector cell is only applied to a small portion of the total area of the pellicle, resulting in a considerably lower response. In addition, there is a leak from under the pellicle which is large with respect to the duct size, which further reduces the pellicle response. The publications [2] and [3] further describe an optical angular measurement for measuring the movement of a pellicle. However, the shape of a pellicle set forth in the cited publications is in practice unfavourable for angular measuring. Consequently, the solution proposed in publications [2] and [3] is not sufficiently responsive for highly accurate measurements and high precision applications.
Furthermore, atomic force microscopy uses cantilever typed pellicles. High frequencies are thus required from the pellicles, and, therefore, pellicles used in atomic force microscopy are not suitable for a photoacoustic detector.
Another problem in photoacoustic detection is a disturbance thereof as a result of external sounds. Thus, if the intra-chamber sound, infiltrated from outside the measuring instrument, is more powerful than the intrinsic noise of a system, the improvement regarding the sensitivity (response) of a detector system does not improve the determination of a gas to be analyzed. A typical method for reducing disturbances created by external sounds is sound proofing. Proofing is capable of damping external sounds at a coefficient of 10000-100000.
Another prior known means of reducing disturbances caused by external sounds comprises the use of double detection for a partial reduction of interfering sounds. In prior known double detection systems, a measuring system is provided which is identical to the regular measuring system, said identical system being denied the access of light, and it only measures sound within the chamber. Then, according to the solutions of prior art systems, there is performed a direct amplification of the difference between the actual measuring signal and a reference signal given by the identical measuring system. However, a problem with double detection systems as described above is e.g. that these systems only function in a special situation over a narrow frequency band. The problem is due to a phase difference created between sensors in the measuring systems.
SUMMARY
Consequently, it is an object of the photoacoustic detector, the sensor for the photoacoustic detector and the method in the optimization of a door used as a sensor for the photoacoustic detector, in accordance with the invention, to eliminate or at least alleviate the above-described prior art problems.
Another object of the photoacoustic detector, the sensor for the photoacoustic detector and the method in the optimization of a door used as a sensor for the photoacoustic detector, in accordance with the invention, is to provide an accurate and highly sensitive photoacoustic detector.
A further object of the present invention is to provide a photoacoustic detector, wherein the effect of disturbance factors resulting from external sounds on a measuring result has been reduced.
A further object of the photoacoustic detector according to a highly preferred embodiment of the present invention is to provide a method for improving the sensitivity of the photoacoustic detector and a photoacoustic detector, in which the photoacoustic detector comprises a sensor formed of a door, the sensitivity of which is improved by lowering a resonance angular frequency of the door.
A further object of the photoacoustic detector according to a highly preferred embodiment of the present invention is to provide a method for determining an optimal size of a chamber of the photoacoustic detector.
A further object of the photoacoustic detector according to a highly preferred embodiment of the present invention is to provide a highly sensitive sensor used in the photoacoustic detector and a method for optimization of the sensor.
In order to fulfill the above objects, among other things, the photoacoustic detector, the sensor for the photoacoustic detector and the method in the optimization of a door used as a sensor for the photoacoustic detector, all according to the invention, are principally characterized by what is set forth in the characterizing clauses of the independent claims.
Thus, in a typical photoacoustic detector of the present invention, the means for detecting pressure variations created in the first chamber by absorbed infrared radiation and/or light comprise at least an aperture provided in the wall of the first chamber, in association with which is provided a door adapted to be movable in response to the movement of a gas, and means for a contactless measurement of the door movement. In this context, the term contactless measurement is used in reference to measuring actions performed without one or more sensor that is attached to a door, or in a mechanical communication or contact to it, such as, for example, without a piezoelectric sensor that is attached to a surface of a door. That is, in contactless measurement, measuring means that disturb and/or suppress the movement of a door, are not attached or connected to a door. Such contactless measuring methods are, for example, different kinds of optical measuring methods. Furthermore, the above mentioned capacity measurement, in which the door of the present invention is arranged as the second sheet, is regarded as a contactless measuring method.
In a preferred photoacoustic detector according to the present invention, the door has a surface area which is at most equal to that of the aperture provided in the first chamber. In this context, the surface area of the aperture refers to a surface area of an imaginary level. The surface area of the door refers to a surface area of an azimuthal projection for a door that is projected in the imaginary level of the aperture. Thus, if the surface of the door is curved, for example, the real surface area of the door can be greater than that of the aperture, but the surface area of the azimuthal projection for a door according to the present invention is also then smaller than the surface area of the aperture.
In a preferred photoacoustic detector according to the present invention, the door is at least by one side mounted on a frame structure encircling the side faces of the door. Very advantageously, the door and the frame are fabricated from silicon, for example by forming a gap in a silicon wafer, the gap separating, excluding attachment points, the door from the rest of the wafer forming the frame.
In a preferred photoacoustic detector according to the present invention, the means for the contactless measurement of the door movement comprise: an optical measuring system, comprising at least one or more light sources for illuminating the door or a part thereof and one or more detectors for receiving light reflected from the door and for measuring the door movement as optical angular and/or translatory measurement, or a capacitive measuring system, whereby the door or a part thereof is coated with metal or the door is fabricated from an electrically highly conductive material, and which measuring system comprises a metal film or a metal-coated diaphragm set in the proximity of the door, as well as means for measuring the capacitance variations of a capacitor established by the door and the metal film. In some applications the system may comprise both optical and capacitive measuring systems. It is also possible that in addition to the optical and/or the capacitive measuring systems the photoacoustic detector comprises also other measuring systems for contactless measurement for the door movement.
In a highly preferred photoacoustic detector according to the present invention the means for the contactless measurement of the door movement are arranged in a second chamber, which constitutes a measuring space with a volume V and which is in communication with the first chamber by way of the aperture of the first chamber aperture.
In a highly preferred photoacoustic detector according to the present invention, in communication with the second chamber is further provided a third chamber which is identical to the first chamber in terms of its size and has an aperture which is identical to that included in the first chamber and connects the third chamber with the second chamber, which aperture of the third chamber is closed with a door similar to that closing the aperture of the first chamber, the movement of which door is measured in a manner similar to that used for measuring the movement of the door closing the first chamber aperture. Hence, the actual measuring signal and the reference signal can be measured separately and calculated for their amplitudes, the difference therebetween enabling an accurate filtration of external noises.
A typical sensor of a photoacoustic detector according to the present invention comprises a panel-like skirt element serving as a door frame, and a door separated from the panel-like skirt element by means of a gap. Preferably, the sensor is arrangable in communication with a chamber included in a photoacoustic detector and containing a gas to be analyzed, such that the door is moved by pressure variations created in the chamber by absorbed infrared radiation and/or light.
The sensor according to a highly preferred embodiment of the present invention does not comprise sensors fixedly mounted thereon and/or fixedly arranged in communication therewith for detecting and/or measuring the door movement.
The most important advantage of the present invention is its accuracy and sensitivity compared with typical photoacoustic detectors.
Furthermore, an advantage of the photoacoustic detector and the sensor of the photoacoustic detector according to the present invention is their simple structure and small size.
The most important advantage of the method in the optimization of a door used as a sensor for the photoacoustic detector according to the present invention is that the method is accurate and easy to apply in the optimization of the photoacoustic detector, and, especially in the optimization of the door used in it.
BRIEF DESCRIPTION OF THE DRAWING FIGURES
The invention will now be described in more detail with reference to the accompanying drawing, in which
FIG. 1 shows schematically a design for a photoacoustic detector of the invention,
FIG. 2 shows schematically a pressure sensor for a photoacoustic detector of the invention obliquely from above,
FIG. 3 a shows schematically a pressure sensor for a photoacoustic detector of the invention from the front,
FIG. 3 b shows schematically a pressure sensor for a photoacoustic detector of the invention in a cross-section,
FIG. 4 a shows schematically the effect of a resonance angular frequency ω 0 on an amplitude A x (ω),
FIG. 4 b shows schematically modeling of a door resonance,
FIG. 5 shows schematically a measuring system of the present invention for the movement of a pressure sensor door on the basis of angular variation of the door,
FIG. 6 shows schematically a light intensity for a double detector in the measuring system of FIG. 5 ,
FIG. 7 shows schematically a measuring system of the present invention for the movement of a pressure sensor door on the basis of a translatory measurement of the door,
FIG. 8 shows schematically a measuring system of the present invention for the movement of a pressure sensor door, based on the use of a Michelson interferometer,
FIG. 9 shows schematically an interference fringe developed on a triple detector in the measuring system of FIG. 8 ,
FIG. 10 shows schematically discontinuities in a tangent,
FIG. 11 shows schematically one preferred door design for a photoacoustic detector of the present invention,
FIGS. 12 a and 12 b show schematically a few optional door designs for a photoacoustic detector of the present invention, and
FIG. 13 shows schematically a measuring system of the present invention for the movement of a pressure sensor door, by means of an optical multiplier based on multiple reflection.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 shows schematically one embodiment for a photoacoustic detector of the present invention. As depicted in the figure, the photoacoustic detector comprises gas-filled chambers V and V 0 , which contain or which can be supplied with a gas to be analyzed at a partial pressure p x and a carrier gas at a partial pressure p N (typically often nitrogen). The first chamber V 0 is composed of an annular housing element 1 , having its first open end provided with a window 2 closing the first end of the chamber, through which infrared radiation or light in general can be guided into the chamber. The window 2 is preferably made highly transparent to infrared radiation and/or light and has preferably a thickness of about 3-6 mm. The chamber V 0 will be subsequently described in more detail regarding its dimensions and optimization thereof. The chamber V 0 has its second open end provided with a silicon door 3 closing the second end of the chamber at least partially, functioning as a pressure sensor, and having its design more closely depicted in FIGS. 2 and 3 . In some special applications, the silicon door 3 can also be replaced with a microphone, a thin Mylar or metal film. Arranged as an extension to the second end of the first chamber V 0 , the photoacoustic detector comprises a second chamber V, constituting a measuring space with a volume V. The measuring space is provided with measuring instruments for the silicon door movement. As shown in FIG. 1 , the measuring space has its second end closed with a reference system, comprising a reference chamber V 0 which is closed at one end and identical to the first chamber V 0 in size. The reference chamber has its first end closed with a silicon door similar to that used for the first chamber.
FIGS. 2 , 3 a and 3 b depict schematically and by way of example one preferred silicon-made door according to the present invention, functioning as a pressure sensor. The pressure sensor comprises a panel-like skirt member 4 serving as a door frame, and a door separated by a slit from the panel-like member. L is a width of the door, h its height, d its thickness, and Δ a width of the slot.
With low IR outputs of a light source conductible through the window into the chamber in a state of equilibrium, when W(t)=W av +W 0 cos(2πft), there follows
( ⅆ T ⅆ t ) T 0 = a x p x 2 l ( cos α ) - 1 W 0 cos ( 2 π ft ) ∑ i c V i m i = a x p x 2 l ( cos α ) - 1 W 0 cos ( 2 π f t ) V 0 ∑ i c V i ρ i , ( 1 )
where a x is an absorption coefficient for a gas at a partial pressure p x , l is a length of the chamber, α is an angle between the IR beam and the centre axis of the chamber, and W(t) is a net light power proceeding into the chamber. That is, W(t) is the light intensity×πR 2 , wherein R is a radius of the chamber, m i is a mass of the gas component, c v i is a specific heat capacity of the corresponding gas, ρ i is a density of the gas i, and V 0 is a volume of the smaller chamber. For example
∑
i
c
V
i
m
i
=
c
V
x
m
x
+
c
V
N
m
N
=
V
0
(
c
V
x
ρ
x
+
c
V
N
ρ
N
)
.
It is a default in equation (1) that τ<<f −1 <<τ 0 , wherein τ 0 is a time constant for heat conduction out of the chamber and τ is a time constant for the conversion of absorption energy to heat.
Further
Δ
T
=
T
(
t
)
-
T
0
=
∫
(
ⅆ
T
ⅆ
t
)
T
0
ⅆ
t
=
a
x
p
x
2
l
(
cos
α
)
-
1
W
0
sin
(
2
π
ft
)
2
π
fV
0
∑
i
c
V
i
ρ
i
.
(
2
)
An equation of state for the ideal gas results in
dp
p
0
+
dV
V
0
=
dT
T
0
.
(
3
)
In the pressure sensor:
dV ≈ 1 2 xA
Adp = kx = F , ( 4 )
where A represents a surface area of the pressure sensor, k is a spring constant, and x is a motion. From equations (3) and (4) is obtained
x
≈
Δ
T
/
T
0
k
Ap
0
+
A
2
V
0
(
ω
=
0
)
.
(
5
)
Because ΔT presented in equation (2) is modulated by an angular frequency ω, it is necessary to examine an equation of motion for the door (or the diaphragm), i.e.
m x ¨ - 2 β m x . + m ω 0 2 ︸ k x = F 0 ⅇ ⅈω t ( 6 )
where F 0 e iωt represents a periodic force, β is an damping constant, ω 0 =√{square root over (k/m)} is a resonance angular frequency, and x is a motion either from the end of a door or from the middle of a door or a diaphragm. The solution for equation (6)
x = ( F 0 / m ) ⅇ ⅈω t ω 0 2 - ω 2 + 2 ⅈωβ , ( 7 )
from which is obtained an amplitude
x
*
x
=
A
x
(
ω
)
=
F
0
/
m
(
ω
0
2
-
ω
2
)
2
+
4
β
2
ω
2
.
(
8
)
Equations (3) and (4) provide for amplitudes
Δ p p 0 = Δ T T 0 - Δ V V 0 = Δ T T 0 - 1 2 A x ( ω ) A V 0
and hence
A x ( ω ) = A Δ p / m ( ω 0 2 - ω 2 ) 2 + 4 β 2 ω 2 = Ap 0 ( Δ T T 0 - A x ( ω ) A 2 V 0 ) m ( ω 0 2 - ω 2 ) 2 + 4 β 2 ω 2 ,
from which
A
x
(
ω
)
=
Ap
0
Δ
T
T
0
m
(
ω
0
2
-
ω
2
)
2
+
4
β
2
ω
2
+
p
0
A
2
2
V
0
(
9
)
FIG. 4 a shows schematically the effect of a resonance angular frequency ω 0 on a door or diaphragm amplitude A x (ω).
If ω=0, then equation (9) results in equation (5), i.e. A x (0)=x, because mω 0 2 =k.
It is preferred that the resonance of a door or a diaphragm be modelled in such a way that the increase of amplitude brought by resonance around ω 0 is not taken into consideration (see FIG. 4 b ). That is, if ω<ω 0 , the result is
A x ( ω ) ≈ Ap 0 Δ T / T 0 m ω 0 2 + p 0 A 2 2 V 0 = p 0 Δ T / T 0 m ω 0 2 A + p 0 A 2 V 0 = p 0 Δ T / T 0 ρ d ω 0 2 + p 0 A 2 V 0 , ( 10 )
and if ω>ω 0 , the result is
A x ( ω ) ≈ p 0 Δ T / T 0 ρ d ω 2 + p 0 A 2 V 0 , ( 11 )
where ρ represents a door (or diaphragm) density and d is a thickness. If resonance is not utilized, it is advisable to use a door (or a diaphragm) at less than the resonance angular frequency ω 0 , i.e. to use equation (10), which indicates that the optimization, i.e. maximization, of amplitude A x (ω) for door (or a diaphragm) movement must be done by means of ω 0 , d, V 0 and A. The lower ω 0 and A are, the higher is A x (ω).
Amplitude reaches a maximum, when
ρ d ω 0 2 + p 0 A 2 V 0
reaches a minimum. This happens when
ρ d ω 0 2 ≈ p 0 A 2 V 0 ( 12 )
and
A
x
opt
(
ω
)
≈
p
0
Δ
T
/
T
0
2
ρ
d
ω
0
2
=
p
0
Δ
T
/
T
0
2
p
0
A
2
V
0
(
13
)
By means of equations (1) and (2), the result from equation (13) is
A x opt ( ω ) ≈ p 0 a x p x l ( cos α ) - 1 W 0 T 0 ω V 0 ∑ i c v i ρ i ρ d ω 0 2 , ( 14 )
where ω≦ω 0 . The equation indicates that the best way to augment a response is to reduce angular frequencies ω and ω 0 . It is to be noted, that by disregarding or without optimizing the term
p 0 A 2 V 0 ,
the best possible optimization result will not be attained. Thus, optimization can and typically should be carried out by optimizing also factors A and/or d. With typical commercially available microphones, the resonance frequency f 0 =ω 0 /2π is typically 10-20 kHz. If a microphone, whose resonance frequency f 0 =20 kHz, is operated close to the resonance frequency, the result is A x opt (20 kHz). If a similar diaphragm is used to construct a new microphone, whose resonance frequency f 0 =500 Hz, then
A x opt ( 500 Hz ) = ( 20 kHz 0 , 5 kHz ) 3 A x opt ( 20 kHz ) = 40 3 A x opt ( 20 kHz ) = 64000 A x opt ( 20 kHz ) , ( 15 )
provided that the microphones are optimized according to equation (12). Further, if a microphone optimized for the frequency of 500 Hz were operated at the frequency of 50 Hz, the response would further grow tenfold and the improvement factor would thus be 640000. The resonance frequency can be decreased on the basis of a subsequent equation (16) by making a door (or a diaphragm) thinner. This provides a further improvement at a ratio d 1 /d 2 provided that the thinning of a door or a diaphragm is technically possible.
Resonance angular frequencies depend on the dimensions and material of a door (or a diaphragm). For a door
ω 0 = 2 E 3 ρ d L 2 ,
A = Lh , ( 16 )
where E is a Young's modulus for the material, ρ is a density, L is a width of the door, h is a height, and d is a thickness.
For a circular metal diaphragm, which is not under tension
ω 0 E = E 3 ρ ( 1 - σ 2 ) 4 d r 2 , ( 17 )
where σ=Poisson's ratio and r is a radius of the diaphragm.
For a tensioned thin film (for example Mylar)
ω 0 T = 2.4 T / μ r = 2.4 r F 2 π r ρ d , ( 18 )
where T represents a tension of the film and μ is a mass/unit area, i.e. μ=m/a=ρdA/A=ρd.
To be exact, even for a thin film (Mylar 2 μm) applies
ω tod 2 = E ω 0 2 + T ω 0 2 , (19)
where nevertheless E ω 0 2 << T ω 0 2 .
If comparison is made between a door according to one exemplary embodiment of the present invention, fabricated from the same material (silicon) and having a height L/s, with a circular diaphragm not under tension, the result will be
A door opt A film opt ≈ s π [ 8 s π ( 1 - σ 2 ) ] 1 3 ≈ 20 , ( 20 )
if s=10, i.e. the door has a height which is one tenth of the width L.
If comparison is made between a door according to one exemplary embodiment of the present invention with a tensioned Mylar film usually employed in prior art microphones, the result will be
A door opt A Mylar opt ≈ 43 ( F N ) 2 5 , ( 21 )
where F represents a total tensile force in Newtons and s=10. The ratio is typically 10-20, depending on how little force F is required to make the film functional.
Thus, a door according to the present invention provides a solution which imparts an improvement of at least one order of magnitude in the response of a sensor. If this improvement is added to that gained by angular frequency, a low resonance door can be created which provides in a highly advantageous manner an improvement of a few million in the response of a sensor.
The use of a door-sensor according to one embodiment of the present invention requires that a slot or gap between the door and the wall be preferably made as narrow as possible. The chamber leaks through the gap, with the result that the sensor has a lower limiting frequency f cut , which is defined by a door gap area a as follows:
f cut ∝ v 0 a V 0 , ( 22 )
where v 0 is a velocity of sound in the chamber and V>>V 0 .
On the other hand, it is beneficial to have a small hole between the chambers for equalizing slow pressure variations between the chambers, and which hole can thus be designed as the above-mentioned gap between the door and the door frame.
The accuracy of a photoacoustic sensor can be improved also by replacing the prior art capacitive measuring of a door (or diaphragm) movement with an optical measuring system of the present invention. Optical measuring causes very little interference with the movement of a door (or a diaphragm). According to the present invention, the movement can be measured either by means of an angle assumed by a door (or a diaphragm) or by means of a translatory movement of some point in a door (or a diaphragm).
FIG. 5 illustrates a measuring system based on angular measurement, wherein an optical indicator in the form of a laser 10 is used, while the detector is a double sensor 11 . Besides a door 3 , which serves as a sensor, the measuring system comprises the laser 10 as a light source, an optical lens 12 for focusing a light beam, and the double sensor 11 for receiving and measuring a light beam v reflected from the door 3 . Hence, the double sensor comprises a first detector d 1 and a second detector d 2 . The light beam v has its focus 13 at the double sensor. FIG. 6 depicts a light power of the measuring system on a double sensor, wherein at each point of y the intensity of light is integrated in a direction perpendicular to y.
In the angular measurement shown in FIGS. 5 and 6 , an angle variation Δα is converted to a translatory motion Δy=a2Δα, which is measured with a double sensor d 1 d 2 . The angle Δα represents an average angle variation in the door area illuminated by a laser beam. Generally, Δα depends on a measuring spot, i.e. l.
tan Δα = FL 2 6 EI [ 1 - ( L - l L ) 3 ] = 8 EI Δ xL 2 6 L 3 EI [ 1 - ( L - l L ) 3 ] = 4 Δ x 3 L [ 1 - ( L - l L ) 3 ] , ( 27 )
or
Δ
y
≈
2
a
4
Δ
x
3
L
[
1
-
(
L
-
l
L
)
3
]
.
(
28
)
The smallest movement that can be measured with a double sensor is
Δ y min = σ 2 ( S / N ) , ( 29 )
where σ is the half width of a laser focus. At its minimum, σ is limited by diffraction, i.e.
σ
≈
λ
D
(
a
+
b
)
.
(
30
)
Thus, the detectable minimum movement at the end of a door is
Δ
x
min
≈
3
L
Δ
y
min
8
a
[
1
-
(
L
-
l
L
)
3
]
=
3
L
λ
(
a
+
b
)
2
D
(
S
/
N
)
8
a
[
1
-
(
L
-
l
L
)
3
]
=
3
L
λ
(
a
+
b
)
16
aD
[
1
-
(
L
-
l
L
)
3
]
(
S
/
N
)
.
(
31
)
The illuminated area at the door has a width aD/[(a+b)cos β], which provides a final limitation. If b≈0 and l≈L, the preceding equation results in
Δ
x
min
≈
3
L
λ
16
D
(
S
/
N
)
.
(
32
)
In practice D≦L, i.e.
Δ x min ≈ 3 λ 16 ( S / N ) , ( 33 )
where S is a laser intensity I 0 and N is a sum noise of light and electronics.
The amplitude of a signal (fluctuation of light power)
A v =ΔP d 1 −ΔP d 2 =2 ΔyI max , (34)
where ΔP d1 and ΔP d2 represent changes of light power at detectors d 1 and d 2 , as well as I max is a maximum light power/Δy. Now, with the help of equation (28)
A v = a 16 A x I max 3 L [ 1 - ( L - l L ) 3 ] ≈ 16 aA x 3 L P d 1 + P d 2 σ [ 1 - ( L - l L ) 3 ] , ( 35 )
where P d1 +P d2 =I 0 represent the light power of a laser falling on the double sensor.
Thus, the optical indicator has a light signal whose amplitude is
A v = 16 aDI 0 A x 3 L λ ( a + b ) ≈ 16 I 0 A x 3 λ , ( 36 )
where A x is the amplitude of door movement x, which must be <λ.
One of the benefits offered by an optical indicator of the present invention is its simple design, it does not interfere with door movement, and the double sensor suppresses the photon noise of laser light. Preferably, the size of a laser light spot on the door is large, D≈L, in order to have a small σ. The optical indicator of the present invention can also be used for measuring a diaphragm movement, the optimal measuring site being r/√{square root over (3)}.
Thus, according to the present invention, the door movement can also be measured in a translatory measurement. FIG. 7 depicts a measuring system of the present invention, which is not an angular measurement and by which a translatory movement x of the door can be measured. In addition to the door, the measuring system comprises a laser 10 serving as a light source, a double sensor 11 , a first optical 12 lens for directing a light beam focus to the surface of a door 3 presently at rest or in stationary condition, and a second optical lens 12 for focusing on the double detector a light beam reflected from the door 3 . The light source, the optical lenses and the double detector are arranged in such a way that, when the door is at rest, the angle between light beams incident on and reflecting from the door is 90 degrees. An advantage of the measurement is among other things that the laser beam is in focus at the door surface and the door may have a poor optical quality. The minimum movement that can be detected by the measuring system is
Δ x min ≈ 2 a λ 4 D ( S / N ) , ( 37 )
if the door has a minor surface.
The minimum movement is in the same order of magnitude as in angular measurement, i.e. Δx min =λ/(S/N), if D=√{square root over (2)}a/4. Translatory measurement is also suitable for measuring a diaphragm movement, as well.
According to one preferred embodiment of the invention, the movement of a door (or a diaphragm) can also be measured optically by using an interferometer. FIG. 8 illustrates one measuring system of the present invention for measuring the movement of a door (or a diaphragm) by means of a so-called Michelson interferometer. As shown in the figure, the system comprises, in addition to the door itself, a laser 10 serving as a light source, an optical lens 12 for focusing a laser beam, a beam splitter 15 or a semi-transparent mirror for splitting the laser beam for the door and for a reference mirror 16 , the reference mirror 16 and a triple sensor 17 for receiving the laser beams coming from the beam splitter 15 . According to what is shown in the figure, the laser beam is approximately in focus both at the door and at the reference mirror. The reference mirror 16 is adjusted such that the triple detector 17 , constituted by three sensors d 1 , d 2 and d 3 , develops ¾ of the interference fringe perpendicular to the plane of paper. When x changes as the door is moving, the interference fringe moves laterally across the detectors, as shown in FIG. 9 . The fringe moves across a single fringe gap, when x changes by λ/2. The intensity distribution of the fringe is
I
(
z
)
=
1
2
A
[
1
+
cos
(
2
π
z
D
)
]
.
(
38
)
If the interference fringe moves by ∈, signals I 1 , I 2 and I 3 of the sensors d 1 , d 2 and d 3 are obtained as follows:
I
1
(
ɛ
)
=
∫
2
D
4
+
ɛ
D
4
+
ɛ
A
2
[
1
+
cos
(
2
π
z
D
)
ⅆ
z
=
AD
2
·
4
+
AD
2
·
2
π
[
-
cos
(
2
π
ɛ
D
)
+
sin
(
2
π
ɛ
D
)
]
,
(
39
)
I
2
(
ɛ
)
=
∫
D
4
+
ɛ
ɛ
A
2
[
1
+
cos
(
2
π
z
D
)
]
ⅆ
z
=
AD
2
·
4
+
AD
2
·
2
π
[
cos
(
2
π
ɛ
D
)
+
sin
(
2
π
ɛ
D
)
]
and
(
40
)
I
3
(
ɛ
)
=
∫
ɛ
D
4
+
ɛ
A
2
[
1
+
cos
(
2
π
z
D
)
]
ⅆ
z
=
AD
2
·
4
+
AD
2
·
2
π
[
cos
(
2
π
ɛ
D
)
-
sin
(
2
π
ɛ
D
)
]
.
(
41
)
Thus,
{ I 2 ( ɛ ) - I 1 ( ɛ ) = AD 2 π cos ( 2 π ɛ D ) I 2 ( ɛ ) - I 3 ( ɛ ) = AD 2 π sin ( 2 π ɛ D ) ( 42 )
or
2
πɛ
D
=
tan
-
1
{
I
2
-
I
3
I
2
-
I
1
}
.
(
43
)
Because ∈=Δz=2DΔx/λ, then
Δ
x
=
λ
4
π
tan
-
1
{
I
2
-
I
3
I
2
-
I
1
}
(
44
)
Since the signals I 2 −I 1 and I 2 −I 3 are in a 90° phase relative to each other, they can provide a way across tangent function discontinuities shown in FIG. 10 . Hence, in equation
Δ x = ( k + 1 2 ) λ 4 + λ 4 π tan - 1 { I 2 - I 3 I 2 - I 1 }
it is possible to measure changes ±1 of an integer k at tangent discontinuities φ=(n+½)π.
The smallest detectable movement is
Δ x min = σ 2 ( S / N ) = λ 8 ( S / N ) , ( 45 )
where S=I 0 /2.
If the door movement is small <λ/4, the triple sensor of the above-described measuring system can be replaced by a double sensor the same way as in the optical indicator. Thus, the combined width of the sensors is equal to the width of a single fringe and
{
I
1
+
I
2
=
AD
2
=
I
0
2
I
1
-
I
2
=
AD
π
sin
(
2
π
ɛ
D
)
.
(
46
)
Because ∈=Δz=2DΔx/λ is
Δ x = λ 4 π sin - 1 { I 1 - I 2 I 1 + I 2 } ≈ λ 8 I 1 - I 2 I 1 + I 2 = λ 4 I 0 ( I 1 - I 2 ) , ( 47 )
where I 0 is the laser light power. Then, the amplitude of the light signal is
A l = I 1 - I 2 ≈ 4 I 0 A x λ , ( 48 )
where A x is the amplitude of the door movement x.
Advantages gained by interferometric measurement according to the present invention include, among other things: According to equation (44), the response is highly linear even when the movement of a door (or a diaphragm) covers several wavelengths. Absolute accuracy is high, because the shape of an interference signal is precisely consistent with ½(1+cos(2πz/D)). In addition, a laser can be focused on the measuring point of a door in an almost dot-like manner and the result is not affected by diffraction. Neither is the value of a measuring result affected by fluctuation of the laser intensity I 0 , since the value of the maximum intensity A is reduced away in equation (44).
When comparing the optical indicator and the interferometer with each other, it can be concluded that the equation (33) does not work out in practice, because a square (rectangular) door is not the optimal form when optimizing the equation (10). That is, in other words, the optical indicator and the interferometer of the present invention function very well also with a square (rectangular) door, but should a further improvement in sensitivity and accuracy be desired, the door shape must be changed. When using a door whose height is one tenth of its width L (i.e. s=10), according to FIG. 11 the equation (31) results in
Δ x min ≈ 3 L λ 16 L / 10 ( S / N ) ≈ 2 λ S / N , ( 49 )
which is 16-fold with respect to the corresponding value of an interferometer (equation (45)). Further, the interferometer will be improved with respect to the optical indicator, if s grows, i.e. the door becomes shorter, which, on the other hand, also increases the amplitude A x (ω) of door movement.
The configuration of a door can still be improved, for example by further reducing a resonance frequency by weakening a door hinge by grooving the hinge in its mid-section as shown in FIG. 12 a and/or by augmenting the surface area of a door at the end of the door as shown in FIG. 12 b . The door design shown in FIG. 12 b is particularly suitable for the multiplier solution of an interferometer as described in more detail hereinafter. The door shown in FIG. 12 b can be realized also by using more than one bar, whereby stiffness of the door increases and rotation of the door resulting in the pressure on the door diminishes. According to the present invention, the door can be realized also in such a manner, that the door, the surface area of which is smaller than the surface of the aperture, is hinged by using a long bar, whereby the structure shown in FIG. 12 a , for example, can act as a bar, the door being attached to a head of the bar or formed as part of an end of the bar. An advantage of a long bar is that the use of a long bar reduces door resonance.
Since the use of an interferometer develops an almost dot-like spot on the door, it is possible to apply multiple reflection, i.e. a multiplier, in the interferometer as shown in FIG. 13 . Laser light v travels to an end mirror, reflecting n times from the door 3 and from a fixed plane mirror 20 , which is mounted in the vicinity of the door and preferably arranged parallel to the door surface. The laser has its focus in the proximity of the end mirror 21 , from which the laser beam returns along the same path, reflecting another n times from the door. If the door nudges a distance Δx, the optical distance changes in the interferometer by 4nΔx and the response increases 2n fold, if there are no reflection losses.
If the mirrors and the door have a reflection coefficient R, the equation (45) adopts now a new form:
x
min
R
=
λ
2
nR
4
n
-
2
8
(
S
/
N
)
=
x
min
2
nR
4
n
-
2
.
(
50
)
This method provides about a 10-fold augmentation of sensitivity. Multiple reflection can also be applied in a laser reflection of the present invention for translatory measurement, since the laser has its focus on the door.
When comparing an optical indicator of the present invention and an interferometer with each other, it can be concluded that both measuring systems of the present invention are capable of providing a substantial improvement regarding the accuracy and sensitivity of measurement. Interferometric measurement is even somewhat more precise than an optical indicator, but at the same time the measuring system is slightly more complicated. Hence, the required sensitivity should be considered in light of a specific application and case for selecting the appropriate measuring method.
As stated above, a problem with prior known photodetectors is disturbance caused by external sounds. According to the present invention, the effect of external sounds can be suppressed by means of a per se known double detector, which is shown in FIG. 1 . According to the present invention, the actual measuring signal and a reference signal are measured separately and calculated for their amplitudes, the difference therebetween enabling a more accurate and effective filtration of external noises. Especially in a frequency range, where there is no signal developed by a gas, the interfering noise can be substantially reduced.
There is no intention whatsoever to limit the invention to the embodiment described in the foregoing disclosure, but it can be varied within the scope of the inventive concept set forth in the claims.
LITERATURE REFERENCES
[1] Nicolas Ledermann et. al., Integrated Ferroelectrics, Vol. 35, pp. 177-184 (2001)
[2] M. H. de Paula et. al., J. Appl. Phys., Vol. 64, 3722-3724 (1988)
[3] M. H. de Paula et. al., Rev. Sci. Instrum., Vol. 673, 3487-3491 (1992)
|
The invention relates to a photoacoustic detector, comprising at least a first chamber (V 0 ) suppliable with a gas to be analyzed, a window for letting modulated and/or pulsed infrared radiation and/or light in the first chamber (V 0 ), and means for detecting pressure variations created in the first chamber by absorbed infrared radiation and/or light. The means for detecting pressure variations created in the first chamber by absorbed infrared radiation and/or light comprise at least an aperture provided in the wall of the first chamber (V 0 ), in communication with which is provided a door arranged to be movable in response to the movement of a gas, and means for a contactless measurement of the door movement. The invention relates also to a sensor for a photoacoustic detector and to a method in the optimization of a door used as a sensor for a photoacoustic detector.
| 6
|
FIELD
The present disclosure relates to an isolation mount used in securing a support structure to a vehicle body, such as a vehicle cradle mount or subframe, and for absorbing vibrations and movements between the two structures.
BACKGROUND
The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Subframe mounts are used extensively in unibody vehicles to isolate vibrations created by road inputs from being transmitted from the engine to the subframe and the body, and vice versa. The operator of the vehicle perceives that vibration isolation relates to ride quality and that improved vehicle dynamics translates into improved handling performance.
Typically, there are as many as four locations on the sub-frame where an isolation mount is utilized. The sub-frame is compressed between the upper portion and the lower portion of the vibration mount and the vehicle body rests on top of the upper mount. A bolt extends through an aperture in the sub-frame and the isolation mount. The lower mount and the upper mount are connected by a weld nut on the body to complete the attachment, of the body to the sub-frame. The mount isolates road inputs and engine or transmission induced vibration that is transmitted along the sub-frame to the body. The mount also improves vehicle dynamics by controlling or attenuating relative movement between the vehicle body and sub-frame in the vertical mode or plane, that is up and down, relative movement, and also to control lateral mode or plane, that is side to side movement, and fore and aft mode or plane, that is front to back relative movement.
A typical design of a sub-frame isolation mount employs a relatively hard or high durometer rubber (typically 40 to 80 Shore A) as an isolating material. High durometer rubber for cradle or sub-frame mounts is an excellent material for improved handling in the lateral plane, especially when it is combined with rate plates to stiffen the response in the lateral plane and to a limited degree the fore and aft plane. However, since the solid elastomeric material is generally very stiff, it does not attenuate vertical forces from the subframe to the body very effectively. As a result, the isolation mount has a high lateral stiffness rate response which is desirable but it has a fore aft stiffness rate response which is marginally acceptable and a vertical stiffness rate response which is low. Therefore, good ride and handling of a vehicle are compromised because of the stiffness properties of the solid elastomeric material.
Thus, there is a need for a vibration isolation mount that provides for ride quality that is satisfactory to the operator without sacrificing the handling characteristics of the vehicle in the lateral plane, fore and aft plane and vertical plane. Additionally, there is a need for a mount that is lighter in weight, improves durability and reduces both initial and high mileage noise, vibration, and harshness between a sub-frame and a body.
SUMMARY
Accordingly, the present disclosure provides a mount assembly for mounting a support structure to a vehicle body, such as a frame, sub-frame or vehicle cradle mount. The mount assembly includes an insert including a generally cylindrical body having an aperture extending therethrough and a first pair of radial projections and a second pair of radial projections. The first pair of radial projections extend at a distance greater than the second pair of radial projections. A microcellular urethane body is press-fit over the insert in order to pre-compress the body. A cup member surrounds a portion of the microcellular urethane body.
Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
DRAWINGS
The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.
FIG. 1 is a cross-sectional view of the body mount assembly according to the principles of the present disclosure;
FIG. 2 is a perspective view of an insert for use with the body mount assembly according to the principles of the present disclosure;
FIG. 3 is a top plan view of the insert of FIG. 2 ;
FIG. 4 is a cross-sectional view of the insert taken along line 4 - 4 of FIG. 3 ;
FIG. 5 is a cross-sectional view of the insert taken along line 5 - 5 of FIG. 3 ;
FIG. 6 is a bottom plan view of a micro-cellular urethane body and cup assembly for use with the mount of FIG. 1 ;
FIG. 7 is a cross-sectional view taken along line 7 - 7 of FIG. 6 ;
FIG. 8 is a perspective view of the cup utilized with the mount assembly shown in FIG. 1 ;
FIG. 9 is a cross-sectional view of the cup of FIG. 8 ;
FIG. 10 is a cross-sectional view of a body mount assembly according to a second embodiment of the present disclosure;
FIG. 11 is a perspective view of an insert utilized with the body mount assembly shown in FIG. 10 ;
FIG. 12 is a top plan view of the insert of FIG. 11 ;
FIG. 13 is a cross-sectional view taken along line 13 - 13 of FIG. 12 ;
FIG. 14 is a bottom view of a micro-cellular urethane body and cup assembly for use with the body mount assembly of FIG. 10 ;
FIG. 15 is a cross-sectional view taken along line 15 - 15 of FIG. 14 ;
FIG. 16 is a perspective view of a cup member utilized with the body mount assembly of FIG. 10 ;
FIG. 17 is a cross-sectional view of the cup member of FIG. 16 ;
FIG. 18 is a cross-sectional view of a body mount assembly according to a third embodiment of the present disclosure;
FIG. 19 is a perspective view of an insert for use with the body mount assembly of FIG. 18 ;
FIG. 20 is a cross-sectional view of the body mount assembly according to the principles of the present disclosure;
FIG. 21 is a second cross-sectional view of the body mount assembly of FIG. 18 ;
FIG. 22 is a perspective view of an alternative cup member according to the principles of the present disclosure; and
FIG. 23 is a cross-sectional view of the cup member shown in FIG. 22 .
DETAILED DESCRIPTION
The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.
With reference to FIG. 1 , a vehicle body mount assembly 10 , according to the principles of the present disclosure, will now be described. The body mount assembly 10 is provided for connecting a support structure, such as a frame, vehicle cradle mount, or subframe 14 , to a vehicle body 12 . The body mount assembly 10 includes an insert 16 received in a micro-cellular urethane body member 18 which is partially surrounded by a cup member 20 . A fastener 22 engages a plate member 24 which is disposed against a lower end of the micro-cellular urethane body 18 . A nut 26 and washer 28 are provided for securing the support structure 14 to the body 12 .
With reference to FIGS. 2-5 , the insert 16 will now be described. The insert 16 includes a generally cylindrical body portion 30 having an aperture 32 extending therethrough. The body portion 30 includes a first pair of radial projections 34 A, 34 B and a second pair of radial projections 36 A, 36 B which are offset from the first pair of radial projections 34 A, 34 B by 90 degrees. As shown in FIGS. 2 , 4 , and 5 , the first pair of radial projections 34 A, 34 B are taller in height than the second pair of radial projections 36 A, 36 B. Furthermore, the first pair of radial projections 34 A, 34 B have a maximum diameter D 1 which is greater than a maximum diameter D 2 of the second pair of radial projections 36 A, 36 B. Each of the radial projections 34 A, 34 B have a height H 1 , and the second pair of radial projections 36 A, 36 B have a height H 2 . It should be understood that the diameters D 1 , D 2 and heights H 1 , H 2 of the radial projections can be varied according to the desired design parameters.
With reference to FIGS. 6 and 7 , the micro-cellular urethane body 18 and cup 20 assembly will now be described. The cup member 20 has a cylindrical body 40 having a first end 40 A provided with a radially outwardly extending flange 42 and a second end 40 B provided with a radially inwardly extending flange 44 . The micro-cellular urethane body 18 is over molded to the cup 20 and includes an aperture 48 extending axially therethrough wherein the aperture 48 is provided with a first pair of oppositely disposed recesses 50 A, 50 B and a second pair of oppositely disposed recesses 52 A, 52 B offset 90 degrees from the first pair of recesses 50 A, 50 B. The first pair of recesses 50 A, 50 B have a height H 3 , and the second pair of recesses 52 A, 52 B have a height H 4 which is less than the height H 3 . The first pair of recesses 50 A, 50 B have a maximum inside diameter ID 1 and the second pair of recesses 52 A, 52 B have a maximum inside diameter ID 2 which is smaller than ID 1 .
The micro-cellular urethane body 18 extends axially beyond the flange portion 42 of cup member 20 and extends radially outward so as to cover at least a portion of the face of the radially outwardly extending flange portion 42 . A second portion 56 of the micro-cellular polyurethane member 18 extends axially beyond the radially inwardly extending flange portion 44 of the cup member 20 so as to surround at least a portion of the radially inwardly extending flange portion 44 . The axially extending micro-cellular urethane portion 56 is disposed against the body member 12 , while the axially extending micro-cellular urethane portion 54 is disposed against the flat plate 24 between the support structure 14 and plate 24 .
The insert 16 is press-fit within the micro-cellular urethane body member 18 such that the diameter of the first pair of radial projections 34 A, 34 B is larger than the inside diameter ID 1 of the first pair of recesses 50 A, 50 B of the micro-cellular urethane body member 18 . Similarly, the diameter D 2 of the second pair of radial projections 36 A, 36 B is greater than the inside diameter ID 2 of the second pair of recesses 52 A, 52 B provided in the micro-cellular urethane body member 18 . Accordingly, the urethane body member is pre-compressed upon insertion of the insert 16 into the micro-cellular urethane body member 18 and cup assembly 20 . The amount of pre-compression of the micro-cellular urethane body member can be determined based upon design parameters and can be selected from a range of between 0 and 50 percent compression relative to the original uncompressed wall thickness dimension. A pre-compression amount of at least 10 percent is desirable in many applications. The amount of pre-compression increases the stiffness of the micro-cellular urethane body member 18 so as to provide desired characteristics in both the lateral and fore and aft directions. The height H 1 , H 2 , H 3 , H 4 can also be selected in order to selectively tune the height of micro-cellular urethane that is being pre-compressed. The body mount assembly of the present invention has been shown to provide high damping in the low frequency range and low damping in a high frequency range as is desired for optimal NVH conditions.
With reference to FIGS. 10-17 , wherein like reference numerals are utilized with the added prefix 1 in order to designate common or similar elements to those described above, a second embodiment of the body mount assembly 110 will now be described. The body mount assembly 110 has a shorter height than the body mount assembly 10 , but utilizes an insert 116 , a micro-cellular urethane body member 118 , and a cup member 120 in a similar manner as described above. The insert 116 is shown including a first pair of radially extending projections 134 A, 134 B and a second pair of radial projections 136 A, 136 B that are each provided with the same height, with the radial projections 134 A, 134 B having a greater diameter than the diameter of the radial projections 136 A, 136 B. Other than that difference, the function and operation of the body mount assembly 110 is substantially the same as the body mount assembly 10 , as described above. Accordingly, a detailed description of the structure and function of the second embodiment of the body mount assembly 110 will not be provided.
With reference to FIGS. 18-21 , a still further embodiment of the body mount assembly 210 will now be described. The body mount assembly 210 is provided for mounting the vehicle body 12 to a support structure 14 similarly to the previously described body mount assemblies 10 , 110 . The body mount assembly 210 includes an insert 216 surrounded by an overmold micro-cellular urethane body member 218 . The insert 216 and over-molded micro-cellular urethane body member 218 are inserted into a cylindrical aperture 220 provided in the vehicle support structure 14 . A plate member 222 is provided between the body 12 and an upper portion of the insert 216 , and includes axially extending flange portion 222 A which is disposed against a separate micro-cellular urethane ring 224 which is also disposed against the support structure 14 .
As shown in FIG. 19 , the insert 216 includes a radially extending flange base portion 230 , an axially extending post portion 232 that includes a first pair of radially extending projections 234 A, 234 B, and a second pair of radial projections 236 A, 236 B extending transverse to the first pair of radial projections 234 A, 234 B. An aperture 238 extends axially through the insert 216 . The micro-cellular urethane body member 218 is over molded around the insert 216 to provide a generally cylindrical outer surface surrounding the insert 216 . A radially extending flange portion 240 of the micro-cellular urethane 218 extends outward over the flange 230 of the insert 216 . In the assembled condition, as illustrated in FIG. 18 , the micro-cellular urethane body member 218 is compressed from its original state, as illustrated in FIGS. 20 and 21 , to a pre-compressed state, as illustrated by phantom lines A and B, as shown in FIGS. 20 and 21 , respectively. As illustrated in FIG. 20 , due to the wider diameter of the radially extending projections 234 A, 234 B as compared to the narrower diameter of the second pair of radial projections 236 A, 236 B, the micro-cellular urethane body member is pre-compressed to a greater extent, as shown in FIG. 20 , than it is pre-compressed in the transverse direction, as shown in FIG. 21 .
It should be noted that the relative direction in the fore, aft, and lateral directions can be specifically tuned to provide the desired NVH characteristics for a specific application. In addition, the assembly of the body mounts 10 , 110 , 210 also can provide pre-compression in the vertical direction via the tightening of the nut on the fastener 22 so as to pre-compress the axially extending portions 54 , 56 of the body mount 10 , 110 , or to compress the radially extending portion 240 and secondary ring 224 in the vertical direction. Thus, the body mount assemblies 10 , 110 , 210 , according to the principles of the present disclosure, are capable of providing lateral, fore, aft, and vertical NVH control with a simple light-weight construction. As described above, the amount of pre-compression can be selected in order to provide desired performance characteristics. In one exemplary embodiment, the amount of pre-compression in a first direction, either lateral or fore and aft, can preferably be approximately 25 percent of the wall's uncompressed thickness, while in the other transverse direction, the pre-compression can be approximately 33 percent.
In addition, in order to provide precision tuning of the body mount assemblies 10 , 110 , 210 , the body mount assemblies 10 , 110 , 210 can be tested for their vibration characteristics, and when deviating from desired characteristics, the cup members 20 , 120 , 220 can be selectively indented, as illustrated in FIGS. 22 and 23 , to provide further precompression of the mirocellular urethane body 18 , 118 , 218 to precision tune the mount assembly for desired characteristics. The diameter and depth of the indentations 70 can be selected to provide the desired adjustments to obtain the desired characteristics. The use of indentation 70 to provide desired vibration damping characteristics can be used with or without pre-compression of the microcellular urethane body. In other words, the microcellular urethane body can be press-fit, simply inserted, or molded in place prior to the indentations 70 being formed in the cup member in order to achieve the desired characteristics. After the body mount is assembled, the vibration characteristics can be tested and compared to desired characteristics. If the vibration characteristics do not meet the desired characteristics, then the cup member can be selectively indented to adjust the vibration characteristics by compressing/or further compressing the microcellular urethane body.
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A body mount for use in motor vehicles in which the mount is sandwiched between the subframe and body. The mount has an insert member with an oblong shape in the lateral displacement direction of the vehicle. The insert member is surrounded by a microcellular urethane body. The oblong shape increases the compression of the microcellular urethane body that can be used to respond to lateral forces. The lateral response rate can be stiffer than the fore and aft response rate. The isolation mount also can facilitate fine tuning thereof by selectively indenting a cup member surrounding the microcellular urethane body to adjust the vibration characteristics of the body mount.
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FIELD OF THE INVENTION
[0001] The invention is directed to compositions, methods and formulations for treatment of hair loss. More particularly, the present invention relates to compositions and methods including minoxidil sulfate, finasteride, and 17α-estradiol for treatment of hair loss by topical administration.
BACKGROUND OF THE INVENTION
[0002] Hair loss is a common skin disorder that affects hair follicles and is characterized by thinning, typically starting at the temples or the crown in men and parietal region in women; continued thinning without treatment leads to atrophy and total loss of hair follicles, which leads to baldness. While the condition is not life threatening and does not endanger health, it leads to social embarrassment and psychological consequences for many sufferers.
[0003] A variety of hair loss treatment methods have been developed, including topical minoxidil, oral finasteride, laser therapy, corticosteroid injections, oral contraceptives, various anti-androgens, and surgical procedures such as hair transplantation. The uses of existing therapies, however, have certain disadvantages.
[0004] Oral finasteride, an effective treatment for many patients, has had a significant number of reported side effects including decreased libido, erectile dysfunction, ejaculatory dysfunction, and myopathy. The Food and Drug Administration (FDA) has additionally issued a statement that the use of finasteride and duatsteride both increase the risk of high grade prostate cancer. Whether or not these side effects are true or exaggerated there is a fear among many patients to initiate or continue treatment.
[0005] Another popular treatment is topical minoxidil. Topical minoxidil is a formulation that contains a high concentration of solvents such as alcohol and propylene glycol both of which lead to skin irritation which reduces patient compliance and reduces the efficacy of the treatment itself (alopecia is often characterized by chronic inflammation). Both topical minoxidil and finasteride are also a single treatment modality; finasteride inhibits the conversion of testosterone to Dihydrotestosterone (DHT) and minoxidil behaves as an ion-channel opener. However, latest research shows that alopecia is caused and triggered by a significant number of variables including exposure to stress, chronic inflammation, perifolicular fibrosis, over-expression or suppression of certain scalp enzymes, auto immune reactions, certain vitamin and mineral deficiencies, sensitivity to DHT, and many more. In addition, there are many more mechanisms involved in alopecia which have not yet been identified. Therefore, it is apparent that while topical minoxidil and oral finasteride have proven efficacy, there address only a single variable and many patients will generally have only partial improvement and not complete improvement of hair loss.
[0006] The risks associated with hair transplantation are well known and its usefulness is limited by the number of hair grafts that can be transplanted to the affected area. Patients who have little hair loss and have a successful transplant still require ongoing topical or oral therapy to prevent the surrounding hair (the non-transplanted hairs) from falling out. These patients are also subjected to the disadvantages of topical minoxidil and oral finasteride.
[0007] For these reasons, it would be desirable to provide improved compositions and methods for the treatment of alopecia. In particular, it would be desirable to provide products which combine multiple mechanisms of action, with none or fewer of the disadvantages described above.
BRIEF SUMMARY OF THE INVENTION
[0008] In a first embodiment, the invention is directed to a pharmaceutical composition for topical application useful for preventing hair loss, stimulating hair growth, treating alopecia, and thickening hair, including (i) 5-alpha-reductase suppressant (ii) an ion channel opener and (iii) 17-alpha estradiol, wherein the (i) 5-alpha-reductase suppressant (ii) an ion channel opener and (iii) 17-alpha estradiol are combined in a pharmaceutically acceptable fluid carrier.
[0009] In another embodiment, the invention is directed to a method to prepare a pharmaceutical composition for topical application useful for preventing hair loss, stimulating hair growth, treating alopecia, and thickening hair including the steps of a. providing a pharmaceutical carrier, b. mixing (i) 5-alpha-reductase suppressant (ii) an ion channel opener and (iii) 17-alpha estradiol in the pharmaceutical carrier and c. depositing the pharmaceutical carrier including the (i) 5-alpha-reductase suppressant (ii) an ion channel opener and (iii) 17-alpha estradiol in a disperserment storage container.
[0010] In another embodiment, the invention is directed to a method for topical application useful for preventing hair loss, stimulating hair growth, treating alopecia, and thickening hair including the steps of a. providing a pharmaceutical carrier, b. mixing (i) 5-alpha-reductase suppressant (ii) an ion channel opener and (iii) 17-alpha estradiol in the pharmaceutical carrier c. depositing the pharmaceutical carrier having the (i) 5-alpha-reductase suppressant (ii) an ion channel opener and (iii) 17-alpha estradiol in a disperserment storage container, and d. applying the pharmaceutical carrier including the (i) 5-alpha-reductase suppressant (ii) an ion channel opener and (iii) 17-alpha estradiol in a disperserment storage container to a required area for treatment as directed.
DETAILED DESCRIPTION OF THE INVENTION
[0011] Certain terminology is used herein for convenience only and is not to be taken as a limitation on the present invention. The terminology includes the words specifically mentioned, derivatives thereof and words of similar import. The embodiments discussed herein are not intended to be exhaustive or to limit the invention to the precise form disclosed. These embodiments are chosen and described to best explain the principle of the invention and its application and practical use and to enable others skilled in the art to best utilize the invention.
[0012] In a first embodiment, the invention is directed to a pharmaceutical composition for topical application useful for preventing hair loss, stimulating hair growth, treating alopecia, and thickening hair, including (i) 5-alpha-reductase suppressant (ii) an ion channel opener and (iii) 17-alpha estradiol, wherein the (i) 5-alpha-reductase suppressant (ii) an ion channel opener and (iii) 17-alpha estradiol are combined in a pharmaceutically acceptable fluid carrier.
[0013] The present invention provides novel hair loss treatment compositions both including minoxidil sulfate (an ion channel opener), finasteride (5α-reductase inhibitor), and 17α-estradiol (secondary 5α-reductase inhibitor). 17α-estradiol differs from finasteride in several respects. It is a stereoisomer of the female hormone 17β-estradiol that inhibits the conversion of testosterone to DHT by suppressing 5α-reductase activity. In addition, by inhibiting 17β-dehydrogenase, it impedes the conversion process of androstenedione to testosterone, resulting in a reduction in the syntheses of testosterone and DHT. It also accelerates the conversion of testosterone to estradiol by stimulating aromatase, decreasing the level of testosterone and leading to a reduction in DHT. The result is broad activity against the main triggers of hair loss. These agents are combined in a pharmaceutically acceptable fluid carrier which has been found to provide effective topical treatment of hair loss.
[0014] The minoxidil sulfate will be present in the carrier at a concentration from 5% by weight to 15% by weight, finasteride will be present at a concentration from 0.01% to 0.5% by weight, and 17α-estradiol will be present at a concentration of 0.01% to 0.1% by weight. By maintaining the compositions at a pH below 7, the tendency of minoxidil sulfate to oxidize and degrade finasteride is largely overcome and the product remains stable during storage at room temperature for extended periods, typically several months or longer. Additionally, the compositions of the present invention have been found to remain substantially odor free even after storage at room temperature for extended period.
[0015] In a particular aspect of the present invention, the use of minoxidil sulfate has significant advantages over minoxidil, which is widely available in many over the counter products. The main distinction between these two compounds is that minoxidil is an oil soluble molecule while minoxidil sulfate is water soluble. The former requires the uses of heavy solvents such as propylene glycol and alcohol which often leads to irritation of the patients scalp. The latter, minoxidil sulfate allows for an almost entirely water mixture wherein the sulfate ion separates during mixing leaving behind pure minoxidil in a water suspension. Not only does this increase patient comfort and reduce irritation, but also leads to a more successful treatment as irritation of the scalp is itself a cause of Alopecia.
[0016] Preparation of the topical compositions by combining these three compounds has a number of advantages. In addition to delivering this composition in a vehicle that is gentler to skin, the three compounds act broadly to deliver multiple mechanisms of action to support optimal functioning of the hair follicle. Due to the fact that the treatment is administered topically, there is a much lower chance of side effects than from oral finasteride and provides an important additional tool for physicians. According to the present invention, topical compositions for the treatment of hair loss include minoxidil sulfate, finasteride and 17α-estradiol present in a fluid carrier or vehicle which is formulated to enhance stability, efficacy, and aesthetic acceptability of the compositions.
[0017] The minoxidil sulfate constituent will be pharmaceutical grade. It may be in the form of a finely divided powder, typically having a mean particle size of 40 μm, or lower, or in the form of a hydrous granular material which will have its particle size reduced accordingly during processing according to this invention. Preparation of suitable minoxidil sulfate constituents is well described in the medical and patent.
[0018] The finasteride constituent will be pharmaceutical grade. It may be in the form of a finely divided powder, typically having a mean particle size of 35 μm, or lower, or in the form of a hydrous granular material which will have its particle size reduced accordingly during processing according to this invention. Preparation of suitable finasteride constituents is well described in the medical and
[0019] 17α-estradiol constituent will be pharmaceutical grade. It may be in the form of a finely divided powder, typically having a mean particle size of 25 μm, or lower, or in the form of a hydrous granular material which will have its particle size reduced accordingly during processing according to this invention. Preparation of suitable 17α-estradiol constituents is well described in the medical and scientific journals.
[0020] The 17α-estradiol, finasteride, and minoxidil sulfate constituents will be combined in a suitable fluid vehicle or carrier, typically an aqueous carrier, but can also be supplied in the form of a gel, cream, lotion, and mixtures thereof. Exemplary polymers include polyacrylamide (CAS Registry No. 9003-05-8) that is available in a mixture containing polyacrylamide & C13-14 isoparaffin & laureth-7 which is commercially available under the tradename Sepigel, Puteaux Cedex, France. Suitable gelling agents include cellulosic polymers, such as gum arabic, gum tragacanth, locust bean gum, guar gum, xanthan.gum, cellulose gum, methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, and hydroxypropylmethylcellulose. The goal of a carrier is to deliver the active molecules to the base of the hair follicle (dermal papilla). Each carrier is evaluated for absorption into skin using various methods including the Franz diffusion method.
[0021] Other ingredients which may optionally be provided in the topical compositions include vitamins, minerals, botanical extracts, humectants, such as propylene glycol; solvents, such as alcohol; and anti-microbial preservatives, such as methylparaben, propylparaben, phenoxyethanol. The topical compositions will also include an organic or inorganic acids, such as lactic acid, which is used to adjust the pH of the initial components and the final product.
[0022] In another embodiment, the invention is directed to a method to prepare a pharmaceutical composition for topical application useful for preventing hair loss, stimulating hair growth, treating alopecia, and thickening hair including the steps of a. providing a pharmaceutical carrier, b. mixing (i) 5-alpha-reductase suppressant (ii) an ion channel opener and (iii) 17-alpha estradiol in the pharmaceutical carrier and c. depositing the pharmaceutical carrier having the (i) 5-alpha-reductase suppressant (ii) an ion channel opener and (iii) 17-alpha estradiol in a disperserment storage container.
[0023] The components could be added to any aqueous solution, gel, or cream and mixed together. The storage container can be a spray, dropper, or lotion pump. The alcohol content of the pharmaceutical carrier is 1.0 to 30.0 percent by weight.
[0024] In another embodiment, the invention is directed to a method for topical application useful for preventing hair loss, stimulating hair growth, treating alopecia, and thickening hair having the steps of a. providing a pharmaceutical carrier, b. mixing (i) 5-alpha-reductase suppressant (ii) an ion channel opener and (iii) 17-alpha estradiol in the pharmaceutical carrier; c. depositing the pharmaceutical carrier comprising the (i) 5-alpha-reductase suppressant (ii) an ion channel opener and (iii) 17-alpha estradiol in a disperserment storage container, and d. applying the pharmaceutical carrier comprising the (i) 5-alpha-reductase suppressant (ii) an ion channel opener and (iii) 17-alpha estradiol in a disperserment storage container to a required area for treatment as needed.
[0025] Treatment should be applied twice per day, morning and night; research illustrates, the first results appear in 90 days. Treatment must be continued indefinitely to maintain results if the patient is affected by male pattern alopecia. If hair loss is caused by other reasons then the treatment should only be used as needed.
[0026] It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. It is understood, therefore, that this invention is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the present invention as defined by the appended claims.
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The present invention is directed to compositions and methods suitable for the treatment of alopecia by topical application include minoxidil sulfate, finasteride, and 17α-estradiol. The combination is characterized by low alcohol content to minimize skin irritation and may be enhanced with the addition of vitamins, minerals, and peptides. The topical use of this combination leads to a lower overall risk of side effects than orally administered drugs.
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BACKGROUND OF THE DISCLOSURE
Retaining wall structures that use horizontally positioned soil inclusions to reinforce an earth mass in combination with a facing element are referred to as Mechanically Stabilized Earth (MSE) structures. MSE structures can be used for various applications including retaining walls, bridge abutments, dams, seawalls, and dikes.
The basic MSE technology is a repetitive process where layers of backfill and horizontally placed soil reinforcing elements are positioned one atop the other until a desired height of the earthen structure is achieved. Typically, grid-like steel mats or welded wire mesh are used as earthen reinforcement elements. In most applications, the reinforcing mats consist of parallel transversely extending wires welded to parallel longitudinally extending wires, thus forming a grid-like mat or structure. Backfill material and the soil reinforcing mats are combined and compacted in series to form a solid earthen structure, taking the form of a standing earthen wall.
In some instances, a substantially vertical concrete wall may then be constructed a short distance from the standing earthen wall. The concrete wall not only serves as decorative architecture, but also prevents erosion at the face of the earthen wall. The soil reinforcing mats extending from the compacted backfill may then be attached directly to the back face of the vertical concrete wall. To facilitate the connection to the earthen formation, the concrete wall will frequently include a plurality of “facing anchors” either cast into or attached somehow to the back face of the concrete at predetermined and spaced-apart locations. Each facing anchor is typically positioned so as to correspond with and couple directly to an end of a soil reinforcing mat.
Via this attachment, outward movement and shifting of the concrete wall is significantly reduced. However, in cases were substantial shifting of the concrete facing occurs, facing anchors may be subject to shear stresses that result in anchor failure. Although there are several methods of attaching the soil reinforcing elements to the facing anchors, it remains desirable to find improved apparatus and methods offering less expensive alternatives and greater resistance to shear forces inherent in such structures.
SUMMARY OF THE DISCLOSURE
Embodiments of the disclosure may provide a connection apparatus for securing a facing to a soil reinforcing element. The connection apparatus may include a soil reinforcing element having a pair of adjacent longitudinal wires with horizontally extended converging portions, a stud having a first end attached to the horizontally extended converging portions, and a second end bent upwards and terminating at a head, a facing anchor having a pair of vertically disposed loops adjacently extending from the facing and having an opening for receiving a vertical portion of the stud, and a device configured to secure the vertical portion of the stud against separation from the opening between the vertically disposed loops, wherein the stud and the attached soil reinforcing element are capable of swiveling in the horizontal and vertical directions.
Another exemplary embodiment of the present disclosure may provide a method of securing a facing to a soil reinforcing element. The method may include providing a soil reinforcing member having a pair of adjacent longitudinal wires having horizontally extended converging portions, providing a stud having a first end attached to the horizontally extended converging portions, and a second end bent upwards forming a vertical portion, wherein the vertical portion terminates at a head, inserting the vertical portion of the stud into an opening defined by a pair of vertically disposed loops adjacently extending from the facing and configured to receive the vertical portion of the stud, and securing the vertical portion of the stud against separation from the opening between the vertically disposed loops, wherein the stud and the attached soil reinforcing member are capable of swiveling in the horizontal and vertical directions.
Another exemplary embodiment of the present disclosure may provide a facing anchor for securing a soil reinforcing element to a facing. The facing anchor may include an unbroken length of continuous wire originating with a pair of lateral extensions and forming at least one pair of vertically disposed U-shaped segments, each having a first end and a second end, wherein the first end includes the U-shaped segments and the second end forming a horizontally disposed loop.
Another exemplary embodiment of the present disclosure may provide a connection apparatus to secure a facing to an earth structure. The connection apparatus may include a stud having a first end attached to a soil reinforcing element, and a second end bent upwards and terminating at a head, a pair of U-shaped wires defining a pair of corresponding apertures and extending from the facing and configured to receive the second end of the stud therebetween, whereby the head rests on the U-shaped wires, and a rod extensible through the pair of apertures and configured to secure the second end of the stud against separation from the U-shaped wires, wherein the stud and the attached soil reinforcing element are capable of swiveling in the horizontal and vertical directions.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A is a top view of a system according to one or more aspects of the present disclosure.
FIG. 1B is a side view of the system shown in FIG. 1A .
FIG. 2 is side view of a connection stud according to one or more aspects of the present disclosure.
FIG. 3A is a side view of an exemplary facing anchor configuration according to one or more aspects of the present disclosure.
FIG. 3B is a perspective view of an exemplary facing anchor according to one or more aspects of the present disclosure.
FIG. 3C is a top view of an exemplary facing anchor according to one or more aspects of the present disclosure.
FIG. 4A is an exploded perspective view of a system according to one or more aspects of the present disclosure.
FIG. 4B is a perspective view of a system according to one or more aspects of the present disclosure.
FIG. 4C is a side view of an exemplary system according to one or more aspects of the present disclosure.
FIG. 5A is a top view of a series of a system according to one or more aspects of the present disclosure.
FIG. 5B is a side view of a series of a system according to one or more aspects of the present disclosure.
DETAILED DESCRIPTION
It is understood that the following disclosure provides several different embodiments, or examples, for implementing different features of the disclosure. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed.
The present disclosure may be embodied as an improved apparatus and method of connecting an earthen formation to a concrete facing of a mechanically stabilized earth (MSE) structure. In particular, one improvement of the present disclosure is a low-cost one-piece MSE connector that allows soil reinforcing mats to shift and swivel in reaction to the settling and thermal expansion/contraction of a MSE structure. Another improvement of the present disclosure is that the connector does not require its lead end to be threadably engageable with the connector. A further improvement includes a soil reinforcing element that is easier to fabricate and ship and thus has less chances for damage during shipping. Besides these improvements resulting in the advantages described below, other advantages of the improved connector and facing anchor combination include its ease of manufacture and installation.
Referring to FIGS. 1A and 1B , illustrated is a system 100 according to one or more aspects of the present disclosure. In an exemplary embodiment, the system 100 may be used to secure a concrete facing 102 to an earthen formation 104 . The facing 102 may include an individual precast concrete panel or, alternatively, a plurality of interlocking precast concrete modules or wall members that are assembled into interlocking relationship. In another embodiment, the precast concrete panels may be replaced with a uniform, unbroken expanse of concrete or the like which may be poured on site. The facing 102 may generally define an exposed face 106 and a back face 108 ; the exposed face 106 typically comprising a decorative architecture facing and the back face 108 located adjacent to the earthen formation 104 . Cast into the facing 102 , or attached thereto, and protruding generally from the back face 108 , is at least one facing anchor 110 .
The earthen formation 104 may encompass an MSE structure including a plurality of soil reinforcing elements 112 that extend horizontally into the earthen formation 104 to add tensile capacity thereto. In an exemplary embodiment, the soil reinforcing elements 112 may include tensile resisting elements positioned in the soil in a substantially horizontal alignment at spaced-apart relationships to one another against the compacted soil. Depending on the application, grid-like steel mats or welded wire mesh may be used as reinforcement elements, but it is not uncommon to employ “geogrids” made of plastic or other materials.
In an exemplary application, as illustrated in FIGS. 1A and 1B , a reinforcing element 112 may include a welded wire grid having a pair of longitudinal wires 114 that are substantially parallel to each other. Transverse wires 116 are joined to the longitudinal wires 114 in a generally perpendicular fashion by welds at their intersections, thus forming a welded wire gridworks. However, in alternative exemplary embodiments any angle will suffice, thus, the transverse wires 116 need not be perpendicular to the longitudinal wires as long as the welded wire grid nonetheless serves its tensile resisting purpose. In an exemplary embodiment, spacing between each longitudinal wire 114 may be about 4 in., while spacing between each transverse wire 116 may be about 6 in. As can be appreciated, however, the spacing and configuration may vary depending on the mixture of force requirements that the reinforcing element 112 must resist. The lead ends 118 of the longitudinal wires 114 generally converge toward one another and are welded to a connection stud 120 .
Referring to the illustrated exemplary embodiment in FIG. 2 , the connection stud 120 may include a cylindrical body 200 bent at the distal end to an angle that may be about 90° relative to the body 200 thus forming a vertical portion 202 . In alternative exemplary embodiments, the angle may be less or even more than 90° and still remain within the workable scope of the disclosure. The vertical portion 202 terminates at a head 204 that is considerably larger than the diameter or cross section of the vertical portion 202 . The tail end 206 of the body 200 may include indentations or thread markings capable of providing stronger resistance welding to the leading ends 118 of the longitudinal wires 114 .
In an exemplary embodiment, the connection stud 120 may include a bolt with a hexagonal or square head, but may also include any material or configuration that encompasses substantially the same design intent. For example, in an alternative embodiment, the connection stud 120 may include a bent segment of bar stock or rebar including a thick washer welded to the top that acts as the head.
Referring to FIGS. 3A and 3C , illustrated are side and top views, respectively, of an exemplary facing anchor 110 according to one embodiment of the present disclosure. As illustrated, the facing anchor 110 may include a pair of exposed vertically disposed loops 302 extending substantially perpendicularly from the back face 108 of the concrete facing 102 . In alternative embodiments, the facing anchor 110 may extend from the concrete facing 108 at various angles to fit any particular application and remain within the scope of the disclosure without departing from the spirit of the disclosure. The loops 302 may be fabricated from a pair of wire segments bent to form a 180° arcuate turn, thus forming a pair of U-shaped segments. The loops 302 may be welded to each other via at least one horizontal wire 304 which forms part of the anchor 110 that is embedded in the concrete panel 102 .
In one embodiment, as illustrated in FIG. 3A , multiple horizontal wires 304 may be employed to render further stability and rigidity to the loops 302 . Wires 304 may be welded to the top and bottom horizontally extending ends of the anchors 110 . In alternative embodiments to fit various applications, the wires 304 may be attached at any suitable surface of the horizontally extending ends of the anchors 110 . Furthermore, as illustrated in FIG. 5A , a pair of panel anchors 110 may be strategically coupled together by welding at least one connecting horizontal wire 304 to each anchor 110 in series. Moreover, a pair of anchors 110 may also be coupled via multiple horizontal wires 304 . As such, stabilized and rigid panel anchors 110 may be strategically placed in the concrete facing 102 at predetermined spaced-apart locations to match up directly with corresponding reinforcing elements 112 . As can be appreciated, any number of panel anchors 110 may be strategically coupled together by welding any number of horizontal wires 304 thereon.
In an alternative embodiment, as illustrated in FIG. 3B , the facing anchor 110 may consist of an unbroken length of continuous wire originating with a pair of lateral extensions 312 . Similar to the embodiment in FIG. 3A , the facing anchor 110 may include a pair of exposed vertically disposed loops 302 , formed by making a pair of 180° arcuate turns, thus forming a pair of U-shaped segments. However, the exemplary facing anchor 110 may also include a horizontally disposed loop 314 formed by making a single 180° arcuate turn to form a singular U-shaped segment. While the vertically disposed loops 302 may be configured to extend substantially perpendicularly from the back face 108 of the concrete facing 102 , the lateral extensions 312 and horizontally disposed loop 314 may be embedded within the facing 102 to provide stability and rigidity to the connection system 100 .
Also contemplated in the present disclosure, but not herein illustrated, is a continuous-wire facing anchor 110 , similar to the embodiment shown in FIG. 3B , but having more than one pair of U-shaped segments 302 configured to extend substantially perpendicularly from the back face 108 of the concrete facing 102 . Thus, an exemplary continuous wire anchor 110 may include a series of U-shaped segment pairs 302 and terminating in a pair of lateral extensions 312 configured to be embedded within the facing 102 to provide stability and rigidity to the connection system 100 . As can be appreciated, the series of U-shaped segment pairs 302 may be spaced apart at predetermined distances, or randomly spaced to accommodate any number or design of soil reinforcing elements 112 .
Referring now to FIG. 3C , which illustrates a top-view of the exemplary system 100 , a reinforcing grid 306 including a plurality of transverse members 308 and horizontal members 310 may also be cast into the concrete facing 102 . In operation, the reinforcing grid 306 may serve to reinforce the concrete facing 102 by providing added tensile strength. Moreover, the grid 306 may be cast into the facing 102 in front of the horizontal wires 304 of the panel anchor 110 so as to provide additional lateral strength for the facing anchors 110 by adding supplementary resistance to being pulled out of the concrete.
Referring to FIGS. 4A and 4B , the soil reinforcing elements 112 are connected to the panel anchors 110 by inserting the vertical portion 202 of the connection stud 120 between the pair of vertically disposed loops 302 of the panel anchor 110 . Since the head 204 of the connection stud 120 is enlarged, the connection stud 120 and reinforcing element 112 combination may rest on the top portion of the loops 302 . Alternatively, as illustrated in FIG. 4C , the soil reinforcing element 112 may be placed on the backfill 104 in a manner so that the head 204 of the connection stud 120 extends above the top portion of the loops 302 a distance Y, instead of resting directly on the loops 302 . Distance Y may be configured to provide a distance wherein the soil reinforcing element 112 may settle as the backfill 104 is compressed over time, thus avoiding potential stress on the connection.
The connection is made secure by extending a rod, such as a threaded bolt 402 , through the dual apertures now defined between the loops 302 , as shown in FIG. 4B . In one embodiment, a nut and washer assembly 404 may be attached to the threaded end of the bolt 402 to prevent its removal. In an alternative embodiment, the threaded bolt 402 may be replaced with any type of connecting pin having the effect of keeping the soil reinforcing element from being removed from the anchor 110 . For example, a segment of wire, metal round stock, or rebar may be effectively utilized by passing said segment through the apertures defined by the vertical loops 302 and manually bending the respective ends of the segment so as to prevent its removal. In alternative embodiments, a pre-fabricated connector pin including prongs on each end may be provided that can be inserted into the apertures defined by the vertical loops 302 and serve to prohibit separation of the anchor 110 from the reinforcing element 112 .
The connection stud 120 allows for movement in certain paths of both the horizontal and vertical planes thus compensating for a wide range of shifting that typically occurs in an MSE structure. For example, it is not uncommon for concrete facings 102 to shift and swivel in reaction to MSE settling or thermal expansion and contraction. Embodiments of the present disclosure may allow shifting and swiveling in the directions and paths indicated by arrows 406 & 408 in FIG. 4A . Therefore, in instances where movement occurs, the soil reinforcements 112 are capable of shifting and swiveling correspondingly thereby preventing damage or misalignment to the concrete facing 102 . Moreover, because the connection stud 120 may swivel, during system 100 construction the soil reinforcing element 112 need not be situated perpendicular to the back face 108 of the facing panel 102 . Instead, the soil reinforcing element 112 may be attached at any angle relative to the back face 108 . In practice, this may prove advantageous since it allows the system 100 to be employed in areas where a vertical obstruction, such as a drainage pipe, catch basin, bridge pile, or bridge pier may be required.
Referring to FIGS. 5A and 5B , illustrated are top and side views, respectively, of an exemplary embodiment of the system 100 of the present disclosure. As can be seen, the system 100 may be employed in series, both vertically and horizontally.
The foregoing disclosure and description of the disclosure is illustrative and explanatory thereof. Various changes in the details of the illustrated construction may be made within the scope of the appended claims without departing from the spirit of the disclosure. While the preceding description shows and describes one or more embodiments, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the present disclosure. For example, various steps of the described methods may be executed repetitively, combined, further divided, replaced with alternate steps, or removed entirely. In addition, different shapes and sizes of elements may be combined in different configurations to achieve the desired earth retaining structures. Therefore, the claims should be interpreted in a broad manner, consistent with the present disclosure.
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A connection apparatus for securing a facing to a soil reinforcing element wherein the soil reinforcing element has a pair of adjacent longitudinal wires with horizontally extended converging portions, a stud having a first end attached to the horizontally extended converging portions, and a second end bent upwards and terminating at a head, a facing anchor having a pair of vertically disposed loops adjacently extending from the facing and having an opening for receiving a vertical portion of the stud, and a device configured to secure the vertical portion of the stud against separation from the opening between the vertically disposed loops, wherein the stud and the attached soil reinforcing element are capable of swiveling in the horizontal and vertical directions.
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FIELD OF THE INVENTION
[0001] The present invention relates to chemical mechanical polishers used for polishing semiconductor wafers in the semiconductor fabrication industry. More particularly, the present invention relates to a new and improved system and process for treating wastewater from a chemical mechanical polisher used in the polishing of semiconductor wafers.
BACKGROUND OF THE INVENTION
[0002] In the fabrication of semiconductor devices from a silicon wafer, a variety of semiconductor processing equipment and tools are utilized. One of these processing tools is used for polishing thin, flat semiconductor wafers to obtain a planarized surface. A planarized surface is highly desirable on a shadow trench isolation (STI) layer, inter-layer dielectric (ILD) or on an inter-metal dielectric (IMD) layer, which are frequently used in memory devices. The planarization process is important since it enables the subsequent use of a high-resolution lithographic process to fabricate the next-level circuit. The accuracy of a high resolution lithographic process can be achieved only when the process is carried out on a substantially flat surface. The planarization process is therefore an important processing step in the fabrication of semiconductor devices.
[0003] A global planarization process can be carried out by a technique known as chemical mechanical polishing, or CMP. The process has been widely used on ILD or IMD layers in fabricating modern semiconductor devices. A CMP process is performed by using a rotating platen in combination with a pneumatically-actuated polishing head. The process is used primarily for polishing the front surface or the device surface of a semiconductor wafer for achieving planarization and for preparation of the next level processing. A wafer is frequently planarized one or more times during a fabrication process in order for the top surface of the wafer to be as flat as possible. A wafer can be polished in a CMP apparatus by being placed on a carrier and pressed face down on a polishing pad covered with a slurry of colloidal silica or aluminum.
[0004] A CMP process is frequently used in the planarization of an ILD or IMD layer on a semiconductor device. Such layers are typically formed of a dielectric material. A most popular dielectric material for such usage is silicon oxide. In a process for polishing a dielectric layer, the goal is to remove typography and yet maintain good uniformity across the entire wafer. The amount of the dielectric material removed is normally between about 5000 A and about 10,000 A. The uniformity requirement for ILD or IMD polishing is very stringent since non-uniform dielectric films lead to poor lithography and resulting window-etching or plug-formation difficulties. The CMP process has also been applied to polishing metals, for instance, in tungsten plug formation and in embedded structures. A metal polishing process involves a polishing chemistry that is significantly different than that required for oxide polishing.
[0005] Important components used in CMP processes include an automated rotating polishing platen and a wafer holder, which both exert a pressure on the wafer and rotate the wafer independently of the platen. The polishing or removal of surface layers is accomplished by a liquid polishing slurry consisting mainly of colloidal silica suspended in deionized water or KOH solution. The slurry is frequently fed by an automatic slurry feeding system in order to ensure uniform wetting of the polishing pad and proper delivery and recovery of the slurry. For a high-volume wafer fabrication process, automated wafer loading/unloading and a cassette handler are also included in a CMP apparatus.
[0006] As the name implies, a CMP process executes a microscopic action of polishing by both chemical and mechanical means. While the exact mechanism for material removal of an oxide layer is not known, it is hypothesized that the surface layer of silicon oxide is removed by a series of chemical reactions which involve the formation of hydrogen bonds with the oxide surface of both the wafer and the slurry particles in a hydrogenation reaction; the formation of hydrogen bonds between the wafer and the slurry; the formation of molecular bonds between the wafer and the slurry; and finally, the breaking of the oxide bond with the wafer or the slurry surface when the slurry particle moves away from the wafer surface. It is generally recognized that the CMP polishing process is not a mechanical abrasion process of slurry against a wafer surface.
[0007] While the CMP process provides a number of advantages over the traditional mechanical abrasion type polishing process, a serious drawback for the CMP process is the difficulty in controlling polishing rates at different locations on a wafer surface. Since the polishing rate applied to a wafer surface is generally proportional to the relative rotational velocity of the polishing pad, the polishing rate at a specific point on the wafer surface depends on the distance from the axis of rotation. In other words, the polishing rate obtained at the edge portion of the wafer that is closest to the rotational axis of the polishing pad is less than the polishing rate obtained at the opposite edge of the wafer. Even though this is compensated for by rotating the wafer surface during the polishing process such that a uniform average polishing rate can be obtained, the wafer surface, in general, is exposed to a variable polishing rate during the CMP process.
[0008] Recently, a chemical mechanical polishing method has been developed in which the polishing pad is not moved in a rotational manner but instead, in a linear manner. It is therefore named as a linear chemical mechanical polishing process, in which a polishing pad is moved in a linear manner in relation to a rotating wafer surface. The linear polishing method affords a more uniform polishing rate across a wafer surface throughout a planarization process for the removal of a film layer from the surface of a wafer. One added advantage of the linear CMP system is the simpler construction of the apparatus, and this not only reduces the cost of the apparatus but also reduces the floor space required in a clean room environment.
[0009] Wastewater from the liquid polishing slurry used in the chemical mechanical polishing process must be properly treated for the removal of copper and other chemicals, as well as slurry particles, from the slurry prior to disposal. A typical conventional wastewater treatment system 10 is shown schematically in FIG. 1. The wastewater treatment system 10 receives the wastewater from a CMP apparatus (not shown) during or after the CMP process. The wastewater treatment system 10 includes one or more wastewater collection tanks 12 , each of which receives the wastewater through an inlet header 11 and wastewater inlet line 13 . Some of the wastewater effluent from the treatment process is distributed into the inlet header 11 through an effluent return line 31 to dilute the wastewater in the collection tank or tanks 12 . The wastewater is distributed from each collection tank 12 through a corresponding wastewater outlet line 14 and valve 16 , and into a reaction tank 18 through a reaction tank inlet line 19 . Sodium hydroxide (NaOH) base may be distributed into the reaction tank 18 through a base infusion line 20 , and sulfuric acid (H 2 SO 4 ) may be distributed into the reaction tank 18 through an acid infusion line 21 , in various proportions to achieve a desired pH of the wastewater in the reaction tank 18 . Selected quantities of PAC (polyaluminum chloride) coagulator are further distributed into the reaction tank 18 from a PAC supply 22 . In the reaction tank 18 , the PAC is rapidly mixed with the wastewater to bind or coagulate with the slurry chemicals in the wastewater and precipitate the chemicals out of solution. A reaction tank outlet line 24 distributes the wastewater, with PAC-bound precipitates, from the reaction tank 18 to a clarifier 25 , which separates the PAC-bound precipitate particles from the wastewater and distributes the purified wastewater effluent to an effluent collection tank 27 through a clarifier outlet line 26 . The PAC-bound slurry particles form a thick sludge which settles in the bottom of the clarifier 25 , and the sludge is periodically removed from the clarifier 25 through a sludge removal line 34 . Finally, the wastewater effluent is distributed to an effluent line 30 through an effluent outlet line 28 and typically through a valve or valves 29 . Excess acid is removed from the effluent line 30 through an acidic waste drain line 32 . Some of the effluent is returned to the inlet header 11 through the effluent return line 31 , to dilute incoming wastewater in the collection tank or tanks 12 , whereas most of the effluent is distributed through an effluent disposal line 33 to a facility disposal system (not shown).
[0010] While the PAC has been shown to adequately coagulate and precipitate out of solution chemicals in wastewater from slurry used in most chemical mechanical polishing applications, PAC has been found to inadequately precipitate chemicals, particularly copper cations, in wastewater from slurry used in copper CMP processes, due to the particular chemicals used in the Cu-CMP polishing slurry. This results in production of a wastewater effluent having a high copper content and poor wastewater quality. Accordingly, a new system and process is needed for properly precipitating slurry chemicals, particularly copper cations, in CMP wastewater for the proper treatment and disposal of the wastewater.
[0011] An object of the present invention is to provide a new and improved process for treating CMP wastewater.
[0012] Another object of the present invention is to provide a new and improved process which effectively removes slurry chemicals from CMP wastewater in the treatment and disposal of the wastewater.
[0013] Still another object of the present invention is to provide a new and improved system and process for treating CMP wastewater in a variety of CMP applications.
[0014] A still further object of the present invention is to provide a new and improved system and process which is effective in treating wastewater from a copper CMP process.
[0015] Yet another object of the present invention is to provide a process which utilizes FSC polymer as a coagulant to remove slurry chemicals from CMP wastewater.
[0016] Still another object of the present invention is to provide a system and process which mixes CMP wastewater effluent with FSC polymer coagulant to remove slurry chemicals from CMP wastewater.
[0017] Yet another object of the present invention is to provide a CMP wastewater treatment system which includes a sludge return line for returning sludge removed from CMP wastewater in the a clarifier to wastewater in the clarifier in order to utilize the returned sludge as a coagulator for the removal of inert particles from the wastewater.
SUMMARY OF THE INVENTION
[0018] In accordance with these and other objects and advantages, the present invention is generally directed to a system and process for the treatment of CU-CMP wastewater, including wastewater from a copper CMP process. In a preferred embodiment, the wastewater treatment system includes a coagulant supply tank from which an FSC polymer coagulant is directed into a reaction tank that separately receives the untreated wastewater. The coagulant may first be mixed with the untreated wastewater in selected ratios to provide a desired dosing quantity of the coagulant in the reaction tank. Accordingly, as the wastewater and the FSC polymer coagulant are vigorously mixed in the reaction tank, the coagulant flocs the slurry chemicals, particularly the copper cations, in the wastewater and effectively removes the chemicals from solution in the wastewater as a precipitate before the wastewater is directed to a clarifier. The clarifier separates the flocked precipitate from the wastewater, and the flocked particles settle on the bottom of the clarifier to form a sludge. Some of the sludge is redistributed back into the clarifier to coagulate inert particles in the wastewater. The result is a wastewater effluent which leaves the clarifier with a low copper content and high wastewater quality.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The invention will now be described, by way of example, with reference to the accompanying drawings, in which:
[0020] [0020]FIG. 1 is a schematic view of a typical conventional system for the treatment of CMP wastewater;
[0021] [0021]FIG. 2 is a schematic view of a CMP wastewater treatment system of the present invention; and
[0022] [0022]FIG. 3 is a schematic view illustrating a typical dosing system for the coagulant in implementation of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0023] The present invention has particularly beneficial utility in treating wastewater from a chemical mechanical polishing apparatus used in the polishing of semiconductor wafer substrates. However, the invention is not so limited in application, and while references may be made to such chemical mechanical polishing apparatus, the present invention is more generally applicable to treating wastewater in a variety of industrial applications.
[0024] Referring next to FIG. 2, an illustrative embodiment of the wastewater treatment system of the present invention is generally indicated by reference numeral 70 and includes one or more wastewater collection tanks 72 , each of which is confluently connected to an inlet header 71 through a corresponding wastewater inlet line 73 . The inlet header 71 receives raw or untreated slurry wastewater from a CMP apparatus (not shown). Wastewater outlet lines 74 are provided in fluid communication with a reaction tank 78 through a valve or valves 76 and a reaction tank inlet line 79 . As shown, the wastewater outlet lines 74 may be confluently connected to one of a pair of wastewater lines 44 which connect a flow indicator 42 of a coagulant dosing system 35 to the reaction tank inlet line 79 . A base infusion line 80 may be connected to the reaction tank 78 for the introduction of sodium hydroxide (NaOH) base into the reaction tank 78 . An acid infusion line 81 may be further connected to the reaction tank 78 for the distribution of sulfuric acid (H 2 SO 4 ) into the reaction tank 78 . Accordingly, in application of the system 70 as hereinafter described, the sodium hydroxide and sulfuric acid may be introduced into the reaction tank 78 in various proportions to achieve a desired pH of the wastewater in the reaction tank 78 . A reaction tank outlet line 84 connects the reaction tank 78 to a clarifier 85 , which is connected to an effluent collection tank 87 through a clarifier outlet line 86 . An effluent outlet line 88 connects the effluent collection tank 87 to an effluent line 90 , typically through a pair of valves 89 . An acidic waste drain line 92 may extend from the effluent line 90 . An effluent return line 91 typically extends from the effluent line 90 to the inlet header 71 . An effluent disposal line 93 extends from the effluent line 90 , beyond the acidic waste drain line 92 .
[0025] Referring to FIGS. 2 and 3, in accordance with the present invention, a coagulant dosing system 35 is provided in the wastewater treatment system 70 for controlled infusion of an FSC polymer coagulant into the reaction tank 78 . As shown in FIG. 2, the coagulant dosing system 35 includes a coagulant supply tank 36 which contains a supply of the liquid FSC polymer coagulant 41 . The FSC polymer coagulant 41 is a strong cation floculator which is capable of precipitating copper cations out of solution in the wastewater, as hereinafter further described. A polymer flow line 37 , which may be fitted with a valve 37 a, as shown in FIG. 4, connects the coagulant supply tank 36 to a flow controller 38 . The flow controller 38 may be any type of flow controller known by those skilled in the art which is capable of controlling the flow volume of a liquid. A polymer flow line 39 , which may be fitted with a valve 39 a, connects the outlet end of the flow controller 38 to one of two inlets of a liquid mixer 40 . A flow indicator 42 is connected to the reaction tank inlet line 79 , typically through the wastewater lines 44 , as heretofore described and shown in FIG. 2. The flow indicator 42 may be any type of flow indicator known by those skilled in the art capable of measuring and indicating the rate of flow of a liquid flowing therethrough. An outlet wastewater line 45 connects the outlet of the flow indicator 42 to a second inlet of the liquid mixer 40 . Finally, a polymer entry line 46 extends from the outlet of the mixer 40 and is provided in fluid communication with the reaction tank 78 , as further shown in FIG. 2.
[0026] Referring again to FIG. 2, and further in accordance with the present invention, a sludge removal line 94 extends from the bottom of the clarifier 85 . A sludge return line 95 extends from the sludge removal line 94 and is connected to the wastewater inlet area of the clarifier 85 . The sludge removal line 95 is typically fitted with one or a pair of valves 96 . A sludge thickener line 97 , typically fitted with a valve or valves 99 , may further connect the sludge removal line 94 to a thickener supply 98 which contains a supply of copper thickener or other thickener for thickening the sludge to a solid form, typically in conventional fashion.
[0027] Referring again to FIG. 2, in typical application of the wastewater treatment system 70 , during operation of a CMP apparatus (not shown), wastewater is generated from the polishing slurry as the slurry is used to polish a semiconductor wafer (not shown). The wastewater is distributed from the CMP apparatus to the wastewater treatment system 70 , typically through the inlet header 71 . Each of the wastewater collection tanks 72 receives and collects the raw wastewater 75 from the inlet header 71 through the respective wastewater inlet lines 73 . The wastewater 75 is distributed from each collection tank 72 through the corresponding wastewater outlet line 74 , valve 76 and reaction tank inlet line 79 , respectively, and into the reaction tank 78 .
[0028] As the raw wastewater 75 is distributed through the reaction tank inlet line 79 into the reaction tank 78 , some of the raw wastewater 75 is distributed through the wastewater lines 44 , through the flow indicator 42 and the outlet wastewater line 45 , respectively, and into the liquid mixer 40 of the coagulant dosing system 35 . Simultaneously, under control by the flow controller 38 , FSC polymer coagulant 41 is distributed from the coagulant supply tank 36 through the polymer flow line 37 , flow controller 38 and polymer flow line 39 , respectively, and into the liquid mixer 40 . The liquid mixer 40 is operated, typically in conventional fashion, to thoroughly mix and disperse the FSC polymer coagulant 41 in the wastewater 75 to define a polymer mixture 47 in the liquid mixer 40 . Preferably, the FSC polymer coagulant 41 is mixed with the wastewater dispersing agent in a concentration of about 0.5% to about 5%, and preferably, about 1%, by weight, of the FSC polymer 41 in the wastewater 75 to define a polymer mixture 47 . The polymer mixture 47 is distributed from the mixer 40 , through the polymer entry line 46 and into the reaction tank 78 . Sodium hydroxide (NaOH) base may be distributed into the reaction tank 78 through the base infusion line 80 , and sulfuric acid (H 2 SO 4 ) may be distributed into the reaction tank 78 through the acid infusion line 81 , in various proportions to achieve a desired pH of the polymer mixture 47 in the reaction tank 78 . A preferred range of pH for the polymer mixture 47 in the reaction tank 78 is 10-11. In the reaction tank 78 , the polymer mixture 47 , which includes the FSC polymer coagulant 41 dispersed in the wastewater 75 , is rapidly mixed and agitated for a period of typically about 5 min. to about 20 min. to flocculate the slurry chemicals, particularly copper cations, in the polymer mixture 47 . Accordingly, the slurry chemicals dissolved in the dispersant wastewater bind to the FSC polymer coagulant molecules and are precipitated out of solution in the polymer mixture 47 . The reaction tank outlet line 84 distributes the flocculated polymer mixture 47 , with FSC-bound slurry chemicals, from the reaction tank 78 to the clarifier 85 . The clarifier 85 separates the FSC-bound chemicals from the wastewater in the polymer mixture 47 and distributes the purified wastewater effluent 48 to the effluent collection tank 87 through the clarifier outlet line 86 . The PAC-bound slurry chemicals form a thick sludge 49 which settles in the bottom of the clarifier 85 , and the sludge 49 flows from the clarifier 85 through the sludge removal line 94 . Some of the sludge 49 is continually recycled back to the intake area of the clarifier 85 through the sludge return line 95 and valve or valves 96 . In the clarifier 85 , the recycled sludge 49 enters the purified wastewater effluent 48 , where the sludge 49 binds inert particles remaining in the purified wastewater effluent 48 . This enhances purification of the wastewater in the clarifier 85 as the sludge 49 , with the inert slurry particles bound thereto, immediately fall to the bottom of the clarifier 85 . The purified wastewater effluent 48 is distributed to the effluent line 90 through an effluent outlet line 88 and the valve or valves 89 . Excess acid may be removed from the purified wastewater effluent 48 in the effluent line 90 through the acidic waste drain line 92 . Some of the purified wastewater effluent 48 may be returned to the inlet header 71 through the effluent return line 91 , to dilute incoming raw wastewater 75 in the collection tank or tanks 72 , as desired. Most of the purified wastewater effluent 48 is typically distributed through the effluent disposal line 93 to a suitable facility disposal system (not shown).
[0029] It has been shown that the wastewater treatment system 70 of the present invention is capable of removing copper cations and other chemicals from the raw wastewater to form a purified wastewater effluent having a copper content of less than 10 mg/liter. This represents a substantial improvement in the quality of the wastewater as compared to that obtained using conventional wastewater treatment systems. It will be appreciated by those skilled in the art that the FSC polymer coagulant is capable of effectively operating over a wide range of system variations.
[0030] While the preferred embodiments of the invention have been described above, it will be recognized and understood that various modifications can be made in the invention and the appended claims are intended to cover all such modifications which may fall within the spirit and scope of the invention.
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A system for the treatment of CMP wastewater, including wastewater from a copper CMP process. The wastewater treatment system includes a coagulant supply tank from which an FSC polymer coagulant is directed into a reaction tank that separately receives the untreated wastewater. The coagulant may be mixed with the untreated wastewater in selected ratios to provide a desired dosing quantity of the coagulant in the reaction tank. As the wastewater and the FSC polymer coagulant are mixed in the reaction tank, the coagulant flocs the slurry chemicals in the wastewater and removes the chemicals from solution in the wastewater as a precipitate before the wastewater is directed to a clarifier. The clarifier separates the flocked precipitate from the wastewater, and the flocked particles settle on the bottom of the clarifier to form a sludge. The sludge is re-distributed back into the clarifier to coagulate inert particles in the wastewater.
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BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
[0001] The present invention relates to an enzymatic resolution process for producing an optically active N-protected-octahydro-1H-indole-2-carboxylic acid, which is a useful intermediate compound for producing pharmaceuticals such as an Angiotensin-converting enzyme inhibitor, or a Bradykinin antagonist.
[0002] For the production of an optically active N-protected-octahydro-1H-indole-2-carboxylic acid, there are known (i) processes using optically active amino acids as a starting material and (ii) processes of optical resolution of indoline-2-carboxylic acid or an octahydro-1H-indole-2-carboxylic acid or derivatives thereof, which are produced from an indole-2-carboxylic acid as a starting material.
[0003] Said processes under item (i) above are a method of using a β-iodoalanine derivative and adipic anhydride as the starting materials as described in the claims of EP No. 1323729 (A1), a method of using an asparaginic acid derivative and 3-bromocyclohexene as the starting materials as described in Example 1 of Japanese Patent No. 2550369, and the like.
[0004] In addition, the processes illustrated under item (ii) above are a method of optically resolving ethyl octahydro-1H-indole-2-carboxylate, which is produced by reducing ethyl indole-2-carboxylate, with 10-camphasulfonic acid as described in Preparation Example 4, of U.S. Pat. No. 5,015,641, a method of optically resolving a tert-butyl octahydro-1H-indole-2-carboxylate with tartaric acid (p.997 J. of Medicinal Chemistry, 30 (6), 992-998, (1987)), a method of optically resolving an N-benzoiloctahydro-1H-indole-2-carboxylic acid with α-methylbenzylamine as disclosed in p.997 J. of Medicinal Chemistry, 30 (6), 992-998, (1987), a method of optically resolving an indoline-2-carboxylic acid prepared from an indole-2-carboxylic acid with α-methylbenzylamine, and subsequently reducing the resolved product to produce an octahydro-2-indolecarboxylic acid as disclosed p.1678, Tetrahedron Letters., 23(16), 1677-1680, (1982), and the like.
[0005] However, the processes using, as the starting material, an optical active amino acid under item (i) above have problems in that they require many steps, and expensive reaction reagents. Moreover, the optical resolution methods under item (ii) above also have problems in that resolution efficiency is insufficient, and further recrystallization is required after the optical resolution.
[0006] A process of using an enzyme for producing an optically active octahydro-1H-indole-2-carboxylic acid or an N-protected species thereof by hydrolyzing an octahydro-1H-indole-2-carboxylate or an N-protected compound thereof is not known.
[0007] According to the present invention, an optically active N-protected-octahydro-1H-indole-2-carboxylic acid can be efficiently produced.
[0008] The present invention provides a process for producing an optically active N-protected-octahydro-1H-indole-2-carboxylic acid of formula (2):
wherein R 2 represents a protecting group of an imino group, and the carbon atoms denoted with asterisks (*) represent asymmetric carbon atoms, which process comprises
reacting a mixture of enantiomers of N-protected-octahydro-1H-indole-2-carboxylate of formula (1):
wherein R 1 is a C1-4 alkyl group, and R 2 is as defined above, with an enzyme capable of asymmetrically hydrolyzing the —CO 2 R 1 group of formula (1), wherein the enzyme is an enzyme
i) produced by a microorganism deposited with accession number FERM BP-6703 or a mutant thereof, ii) comprising a polypeptide sequence of SEQ ID NO:1, or iii) comprising a polypeptide sequence of SEQ ID NO:1 modified by deletion, substitution or both of at least one amino acid.
DETAILED DESCRIPTION OF THE INVENTION
[0013] Hereinafter, the present invention will be set forth in detail.
[0014] N-protected-octahydro-1H-indole-2-carboxylate of formula (1) is explained first. The C1-4 alkyl group represented by R 1 includes, for example, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, and a tert-butyl group.
[0015] The protecting groups of the imino group represented by R 2 include, for example, alkoxycarbonyl groups such as a tert-butoxycarbonyl group, arylalkyloxycarbonyl groups such as a benzyloxycarbonyl group, a p-methoxybenzyloxycarbonyl group and a p-nitrobenzyloxycarbonyl group, allyloxy and alkoxycarbonyl groups such as an allyloxycarbonyl group and a 9-fluorenylmethoxycarbonyl group, acyl groups such as an acetyl group and a benzoyl group, substituted alkyl groups such as a benzyl group, and the like.
[0016] Preferred R 2 groups are a tert-butoxycarbonyl group, a benzyloxycarbonyl group, an acetyl group, a benzoyl group and benzyl group, and more preferred is a benzyloxycarbonyl group, which can be readily deprotected to derivatize the protected compounds, for example, to intermediate compounds for the production of the Angiotensin-converting enzyme inhibitor or Bradykinin antagonist.
[0017] The N-protected-octahydro-1H-indole-2-carboxylic acid ester to be resolved, hereinafter referred to also as “substrate”, can be produced, e.g., in accordance with the method described in Journal of Medicinal Chemistry, 30 (6), 992, (1987), by catalytic hydrogenation to reduce an indole-2-carboxylate, and subsequently protecting the imino group of the obtained octahydro-1H-indole-2-carboxylate by a known manner or by a similar manner as described in Drug Design and Discovery (1992), 9(1), 11-28.
[0018] The substrate that was produced by a method other than the above-described method may also be used.
[0019] Examples of the substrate include, for example,
methyl N-tert-butoxycarbonyloctahydro-1H-indole-2-carboxylate, ethyl N-tert-butoxycarbonyloctahydro-1H-indole-2-carboxylate, n-propyl N-tert-butoxycarbonyloctahydro-1H-indole-2-carboxylate, isopropyl N-tert-butoxycarbonyloctahydro-1H-indole-2-carboxylate, n-butyl N-tert-butoxycarbonyloctahydro-1H-indole-2-carboxylate, isobutyl N-tert-butoxycarbonyloctahydro-1H-indole-2-carboxylate, sec-butyl N-tert-butoxycarbonyloctahydro-1H-indole-2-carboxylate, tert-butyl N-tert-butoxycarbonyloctahydro-1H-indole-2-carboxylate, methyl N-benzyloxycarbonyloctahydro-1H-indole-2-carboxylate, ethyl N-benzyloxycarbonyloctahydro-1H-indole-2-carboxylate, n-propyl N-benzyloxycarbonyloctahydro-1H-indole-2-carboxylate, isopropyl N-benzyloxycarbonyloctahydro-1H-indole-2-carboxylate, n-butyl N-benzyloxycarbonyloctahydro-1H-indole-2-carboxylate, isobutyl N-benzyloxycarbonyloctahydro-1H-indole-2-carboxylate, sec-butyl N-benzyloxycarbonyloctahydro-1H-indole-2-carboxylate, tert-butyl N-benzyloxycarbonyloctahydro-1H-indole-2-carboxylate, methyl N-p-methoxybenzyloxycarbonyloctahydro-1H-indole-2-carboxylate, ethyl N-p-methoxybenzyloxycarbonyloctahydro-1H-indole-2-carboxylate, n-propyl N-p-methoxybenzyloxycarbonyloctahydro-1H-indole-2-carboxylate, isopropyl N-p-methoxybenzyloxycarbonyloctahydro-1H-indole-2-carboxylate, n-butyl N-p-methoxybenzyloxycarbonyloctahydro-1H-indole-2-carboxylate, isobutyl N-p-methoxybenzyloxycarbonyloctahydro-1H-indole-2-carboxylate, sec-butyl N-p-methoxybenzyloxycarbonyloctahydro-1H-indole-2-carboxylate, tert-butyl N-p-methoxybenzyloxycarbonyloctahydro-1H-indole-2-carboxylate, methyl N-p-nitrobenzyloxycarbonyloctahydro-1H-indole-2-carboxylate, ethyl N-p-nitrobenzyloxycarbonyloctahydro-1H-indole-2-carboxylate, n-propyl N-p-nitrobenzyloxycarbonyloctahydro-1H-indole-2-carboxylate, isopropyl N-p-nitrobenzyloxycarbonyloctahydro-1H-indole-2-carboxylate, n-butyl N-p-nitrobenzyloxycarbonyloctahydro-1H-indole-2-carboxylate, isobutyl N-p-nitrobenzyloxycarbonyloctahydro-1H-indole-2-carboxylate, sec-butyl N-p-nitrobenzyloxycarbonyloctahydro-1H-indole-2-carboxylate, tert-butyl N-p-nitrobenzyloxycarbonyloctahydro-1H-indole-2-carboxylate, methyl N-allyloxycarbonyloctahydro-1H-indole-2-carboxylate, ethyl N-allyloxycarbonyloctahydro-1H-indole-2-carboxylate, n-propyl N-allyloxycarbonyloctahydro-1H-indole-2-carboxylate, isopropyl N-allyloxycarbonyloctahydro-1H-indole-2-carboxylate, n-butyl N-allyloxycarbonyloctahydro-1H-indole-2-carboxylate, isobutyl N-allyloxycarbonyloctahydro-1H-indole-2-carboxylate, sec-butyl N-allyloxycarbonyloctahydro-1H-indole-2-carboxylate, tert-butyl N-allyloxycarbonyloctahydro-1H-indole-2-carboxylate, methyl N-9-fluorenylmethoxycarbonyloctahydro-1H-indole-2-carboxylate, ethyl N-9-fluorenylmethoxycarbonyloctahydro-1H-indole-2-carboxylate, n-propyl N-9-fluorenylmethoxycarbonyloctahydro-1H-indole-2-carboxylate, isopropyl N-9-fluorenylmethoxycarbonyloctahydro-1H-indole-2-carboxylate, n-butyl N-9-fluorenylmethoxycarbonyloctahydro-1H-indole-2-carboxylate, isobutyl N-9-fluorenylmethoxycarbonyloctahydro-1H-indole-2-carboxylate, sec-butyl N-9-fluorenylmethoxycarbonyloctahydro-1H-indole-2-carboxylate, tert-butyl N-9-fluorenylmethoxycarbonyloctahydro-1H-indole-2-carboxylate, methyl N-acetyloctahydro-1H-indole-2-carboxylate, ethyl N-acetyloctahydro-1H-indole-2-carboxylate, n-propyl N-acetyloctahydro-1H-indole-2-carboxylate, isopropyl N-acetyloctahydro-1H-indole-2-carboxylate, n-butyl N-acetyloctahydro-1H-indole-2-carboxylate, isobutyl N-acetyloctahydro-1H-indole-2-carboxylate, sec-butyl N-acetyloctahydro-1H-indole-2-carboxylate, tert-butyl N-acetyloctahydro-1H-indole-2-carboxylate, methyl N-benzoyloctahydro-1H-indole-2-carboxylate, ethyl N-benzoyloctahydro-1H-indole-2-carboxylate, n-propyl N-benzoyloctahydro-1H-indole-2-carboxylate, isopropyl N-benzoyloctahydro-1H-indole-2-carboxylate, n-butyl N-benzoyloctahydro-1H-indole-2-carboxylate, isobutyl N-benzoyloctahydro-1H-indole-2-carboxylate, sec-butyl N-benzoyloctahydro-1H-indole-2-carboxylate, tert-butyl N-benzoyloctahydro-1H-indole-2-carboxylate, methyl N-benzyloctahydro-1H-indole-2-carboxylate, ethyl N-benzyloctahydro-1H-indole-2-carboxylate, n-propyl N-benzyloctahydro-1H-indole-2-carboxylate, isopropyl N-benzyloctahydro-1H-indole-2-carboxylate, n-butyl N-benzyloctahydro-1H-indole-2-carboxylate, isobutyl N-benzyloctahydro-1H-indole-2-carboxylate, sec-butyl N-benzyloctahydro-1H-indole-2-carboxylate, tert-butyl N-benzyloctahydro-1H-indole-2-carboxylate, and the like.
[0094] The substrate may be a mixture of eight optical isomers, which mixture is typically a racemic mixture, or may be a mixture of a single optical isomer and an antipode thereof. Preferred is the mixture of a single optical isomer and an antipode thereof.
[0095] More preferred is a mixture of the compound of formula (1′) and the antipode thereof of formula (1″).
wherein R 1 and R 2 are as defined above.
[0096] The enzymes capable of asymmetrical hydrolyzing the substrate to produce an optically active N-protected-octahydro-1H-indole-2-carboxylic acid include, for example, a hydrolase including esterase and lipase, originated from a microorganism Chromobacterium SC-YM-1 strain(FERM BP-6703) or a mutant thereof.
[0097] The enzymes may be, for example, an enzyme derived from a mutant produced from the aforementioned microorganism by treatment such as a mutation agent or ultraviolet rays, an enzyme produced by a recombinant microorganism transformed by introducing the gene encoding the present enzyme, and a mutant enzyme produced by addition, substitution or deletion of at least one amino acid in the amino acid sequence of the enzyme by means of the genetic engineering method.
[0098] The recombinant microorganisms can be prepared by introducing genes encoding the enzymes, for example, in accordance with the genetic engineering processes described in, e.g., Molecular Cloning 2nd edition, written by J. Sambrook, E. F. Fritsch, and T. Maniatis, Cold Spring Harbor Laboratory, published in 1989, etc.
[0099] More specifically, the enzymes can be prepared in a similar manner as described in Japanese Unexamined Patent Application Publication No. 7-163364.
[0100] The mutant enzyme can be prepared by genetic engineering process, for example, of Olfert Landt et al. (Gene 96 125-128 1990). More specifically, the mutant enzymes can be prepared as described in Japanese Unexamined Patent Application Publication Nos. 2000-78988 and 7-213280.
[0101] Examples of the mutant enzyme that can be prepared in this manner include, for example, a mutant esterase prepared from an esterase derived from Chromobacterium SC-YM-1 strain, and specific examples thereof include, for example, an enzyme having amino acid substitution(s) or deletion or both in the amino acid of SEQ ID NO: 1. Examples of the substitution(s) or deletion or both are denoted by 160A, 160I, 160L, 160S, 160V, 189A, 189F, 189H, 189I, 189L, 189R, 189S, 189T, 189V, 189Y, 160A189F363term, 160A189H363term, 160A189Y363term, 160S189F363term or 160S189H363term, which notations mean that the 160th and/or 189th amino acids, which are glycine in SEQ ID NO:1, are substituted with the amino acid A, I, L, V, F, H, R, S, T or Y in SEQ ID NO:1 and 363term means that the polypeptide is terminated at the 363rd position and consists of the 1st to 362nd amino acids in SEQ ID NO 1. For example, 160A189Y363term means an enzyme having alanine at 160th position and tyrosine at 189th position in place of glycine in SEQ ID NO:1 and deletion of 8 C-terminal amino acids in SEQ ID NO:1.
[0102] The microorganism capable of producing the enzyme can be liquid cultivated by a known manner. Various medium containing, as required, carbon sources, nitrogen sources, inorganic substances and the like can be used for the cultivating microorganisms.
[0103] For instance, the carbon sources include glucose, glycerin, an organic acid, honey, and the like. The nitrogen sources include a peptone, yeast extract, malt extract, a soybean powder, a corn steep linker, a cottonseed powder, dry yeast, casamino acids, ammonium chloride, ammonium nitrate, ammonium sulfate, urea, and the like.
[0104] The inorganic substances include hydrochlorides of metals such as potassium, sodium, magnesium, iron, manganese, cobalt, zinc, and the like; sulfates of metals mentioned above; phosphates of the aforementioned metals; and the like. More specifically, the salts that may be used include potassium chloride, sodium chloride, magnesium sulfate, ferrous sulfate, manganese sulfate, cobalt chloride, zinc sulfate, potassium phosphate, sodium phosphate, and the like.
[0105] In addition, triglycerides such as olive oil or tributyrin, or the above-mentioned substrate may be added to the medium to enhance the capability of the microorganism capable of asymmetrically hydrolyzing the ester of formula (1).
[0106] The cultivation is suitably carried out under an aerobic atmosphere, and preferred are the shake cultivation or the aeration shake cultivation. The cultivation temperature is normally from about 20 to about 40° C., preferably from about 25 to 35° C. The pH is preferably from about 6 to about 8. The cultivation time may vary depending on various conditions, but is preferably from about 1 day to 7 days.
[0107] Solid cultivation method may also be used to obtain a microorganism cells capable of asymmetrical hydrolyzing the above-described substrate.
[0108] The enzyme can be purified by a suitable method as usually used in the purification of enzymes. For instance, the cultivated cells of the microorganisms are first disrupted by supersonic treatment, Dyno-Mill treatment or French press treatment. Then, after removal of insoluble materials from the disrupted mixture, the desired enzyme can be obtained by centrifugation or the like, and can be further purified by a suitable purification method such as cation ion exchange chromatography, anion ion exchange chromatography, hydrophobic column chromatography, or gel filtration column chromatography, or by a combination thereof normally employed for enzyme purification.
[0109] Examples of the carrier that may be used for such a column chromatography include, for example, DEAE-Sepharose fastflow (manufactured by Amersham Pharmacia Biotech, Inc.), Butyl-Toyopearl 650S (manufactured by Tosoh Co., Ltd.) and the like.
[0110] The enzyme can be used in various forms such as a purified enzyme, a crude enzyme, cultivated products of the microorganisms producing the enzyme, the cells of the microorganisms, treated products thereof, or the like. The aforementioned treated products stand for, for instance, a freeze-dried, acetone-dried, disrupted, autolysate, ultrasonically treated, extracted, or alkali-treated cells of the microorganism producing the enzyme. Furthermore, the enzyme with various purities or forms as mentioned above can be used after immobilization, for example, by means of a well-known method including absorption to inorganic carriers such as silica gel or ceramics, cellulose, or ion exchange resin, the polyacrylamide method, sulfur-containing polysaccharide gel methods such as the carrageenan gel method, the alginic acid gel method, the agar gel method, and the like.
[0111] The amount of the enzyme that may be used is suitably determined so as not to cause a delay of the reaction rate and reduction of selectivity. For instance, the purified enzyme or the crude enzyme is normally used in an amount of from about 0.001 to about 2 parts by weight, preferably from about 0.002 to 0.5 part by weight per one part by weight of the amount of the substrate.
[0112] Cultivated products of the microorganisms, cells of the microorganisms or treated products thereof is usually used in the amount of from about 0.01 to about 200 parts by weight and it is preferably from about 0.1 to 50 parts by weight per one part by weight of the above-described substrate.
[0113] Water may be added as an aqueous buffer in the asymmetrical hydrolysis reaction. The aqueous buffers include, for example, aqueous buffers of inorganic acid salts, and examples thereof include, for example, aqueous alkali metal phosphate solutions such as an aqueous sodium phosphate solution or an aqueous potassium phosphate solution, aqueous buffers of organic acid salts of alkali metal acetates such as an aqueous sodium acetate solution, or an aqueous potassium acetate solution, and the like.
[0114] The amount of the water that may be used normally ranges from 0.5 part by weight to 200 parts by weight per one part by weight of the substrate.
[0115] The asymmetrical hydrolysis reaction in the present invention may also be carried out in the presence of an organic solvent such as a hydrophobic organic solvent, a hydrophilic organic solvent, or the like.
[0116] The hydrophobic organic solvents include, for example, aliphatic ethers such as tert-butyl methyl ether or diisopropyl ether; hydrocarbons such as toluene, hexane, cyclohexane, heptane, octane or isooctane; and the like.
[0117] In addition, the hydrophilic organic solvents include, for example, alcohols such as tert-butanol, methanol, ethanol, isopropanol, isobutanol or n-butanol, alicyclic ethers such as tetrahydrofuran; sulfoxides such as dimethylsulfoxide; ketones such as acetone; nitrites such as acetonitrile; amides such as N,N-dimethylformamide, and the like.
[0118] These hydrophobic organic solvents and hydrophilic solvents are each used singly or as a mixture of two or more of them. A mixture of the hydrophobic organic solvent and the hydrophilic solvent may also be used.
[0119] The solvent is preferably used in the amount of 200 parts by weight or less, more preferably from 0.1 to 100 parts by weight per one part by weight of the substrate.
[0120] The asymmetrical hydrolysis reaction is carried out, for example, by mixing water, the substrate and the enzyme, or by mixing the organic solvent, water, the substrate, and the enzyme.
[0121] The pH of the reaction system is suitably set so that asymmetrical hydrolysis reaction selectively proceeds.
[0122] The pH of the reaction system is normally adjusted within a range of from about 4 to about 10, preferably from about 6 to about 8 by adding a base.
[0123] The bases that may be used include, for example, alkali metal hydroxides such as sodium hydroxide or potassium hydroxide, alkali metal carbonates such as sodium carbonate or potassium carbonate, alkali earth metal carbonates such as calcium carbonate, alkali metal bicarbonates such as sodium bicarbonate or potassium bicarbonate; phosphates such as sodium dihydrogenphosphate, disodium hydrogenphosphate, potassium dihydrogenphosphate, or dipotassium hydrogenphosphate, organic bases such as triethylamine or pyridine, ammonia, and the like. The base may be used solely, or in a mixture of two or more of them. The base is normally added as an aqueous solution, but may also be added as a mixture of an organic solvent and water. The same organic solvent as used in the reaction may also be used for this purpose. Furthermore, the base may be added as a solid, or as a suspension.
[0124] The reaction temperature normally ranges from about 5 to 65° C., preferably from about 20 to 50° C.
[0125] The reaction mixture containing the optically active N-protected-octahydro-1H-indole-2-carboxylic acid of formula (2), hereinafter referred to as asymmetrically hydrolyzed carboxylic acid or as optically active carboxylic acid, and the optically active N-protected-octahydro-1H-indole-2-carboxylic acid ester, which was not hydrolyzed, hereinafter referred to as a remaining ester(s) is obtained.
[0126] The optically active carboxylic acid and the remaining ester are usually separated from the reaction mixture, and also from the enzyme and buffer solution, and the optically active carboxylic acid and the remaining ester are usually separated each other by suitable after-treatment operations such as extraction, phase separation, and/or evaporation of the solvent and optionally silica gel column chromatography and the like.
[0127] An organic solvent miscible with both water and the hydrophobic organic solvent used in the reaction is typically removed by distillation prior to phase separation, if appropriate.
[0128] Insolubles that may be present in the reaction mixture such as the enzyme, an immobilizing carrier, and the like can be removed by filtration, if necessary.
[0129] The extraction and phase separation is typically conducted by adjusting the pH of the reaction mixture with a suitable acid or base within a range of from about 6 to about 12, preferably from about 7 to about 10.
[0130] The acids include, for example, inorganic acids such as hydrogen chloride, hydrogen bromide, sulfuric acid and phosphoric acid, acidic salts of inorganic acids thereof and metals, organic acids such as acetic acid, citric acid and methanesulfonic acid, and acidic salts of organic acids thereof and metals. The same bases as used in adjusting the pH of the hydrolysis reaction can also be used. The separation by extraction may be repeated a plurality of times, if necessary.
[0131] The residual ester remaining in the reaction mixture is usually extracted with a hydrophobic organic solvent followed by phase separation while separated water phase containing the asymmetrically hydrolyzed optically active carboxylic acid is obtained.
[0132] The hydrophobic organic solvents that may be used in the extraction above include, for example, aliphatic ethers such as tert-butylmethyl ether and isopropyl ether; hydrocarbons such as toluene, hexane, cyclohexane, heptane, octane or isooctane; halogenated hydrocarbons such as dichloromethane, dichloroethane, chloroform, chlorobenzene or o-dichlorobenzene: and esters such as methyl acetate, ethyl acetate, or butyl acetate.
[0133] The amount of the hydrophobic organic solvent that may be used is not particularly limited and is normally from 0.1 to 200 parts by weight, preferably from about 0.2 to about 100 parts by weight per one part by weight of the substrate.
[0134] Alternatively, the hydrophobic organic solvent used in the asymmetrical hydrolysis reaction may also serve as extraction solvent and the resulting reaction mixture is settled and separated into the organic phase and water phase without adding the hydrophibic organic solvent, or a suitable amount of the hydrophobic organic solvent for phase separation and extraction may be added.
[0135] The residual ester in the organic phase, which is separated from the optically active carboxylic acid can be isolated by removing the organic solvent of the organic phase by distillation. The isolated residual ester may be further purified by column chromatography or the like, if necessary.
[0136] The residual ester thus obtained can be further hydrolyzed with an alkali to produce the optically active N-protected-octahydro-1H-indole-2-carboxylic acid, which can be further purified by column chromatography, recrystallization, or the like, if necessary.
[0137] The optically active carboxylic acid produced by the asymmetrical hydrolysis is usually present in the separated water phase and is isolated from the water phase normally by adjusting the pH of the water phase with a suitable acid or base within a range from about 1 to about 6, preferably from about 2 to about 5, by extracting the optically active carboxylic acid with an hydrophobic organic solvent as used above for extracting the unreacted ester, and by phase separation typically followed by evaporation of the hydrophobic organic solvent of the organic phase containing the optically active carboxylic acid, thereby water-soluble components such as the enzyme or the buffer are removed. The same acid or base as described above can be also used to adjust the pH.
[0138] The amount of the hydrophobic organic solvent that may be used is normally from about 0.1 to about 200 parts by weight, preferably from about 0.2 to 100 parts by weight per one part by weight of the substrate. The extraction of the desired compound typically followed by phase separation may also be repeated, if necessary.
[0139] The isolated carboxylic acid may be further purified by column chromatography, recrystallization, or the like, if necessary.
[0140] The optically active N-protected-octahydro-1H-indole-2-carboxylic acid of formula (2) include the following compounds:
optically active N-tert-butoxycarbonyloctahydro-1H-indole-2-carboxylic acid, optically active N-benzyloxycarbonyloctahydro-1H-indole-2-carboxylic acid, optically active N-p-methoxybenzyloxycarbonyloctahydro-1H-indole-2-carboxylic acid, optically active N-p-nitrobenzyloxycarbonyloctahydro-1H-indole-2-carboxylic acid, optically active N-aryloxycarbonyloctahydro-1H-indole-2-carboxylic acid, optically active N-9-fluorenylmethoxycarbonyloctahydro-1H-indole-2-carboxylic acid, optically active N-acetyloctahydro-1H-indole-2-carboxylic acid, optically active N-benzoyloctahydro-1H-indole-2-carboxylic acid, optically active N-benzyloctahydro-1H-indole-2-carboxylic acid, and the like.
[0150] According to the present invention, a mixture of (2S, 3aS, 7aS) and (2R, 3aR, 7aR) N-protected-octahydro-1H-indole-2-carboxylate esters are asymmetrically hydrolyzed to give the optically active N-protected-octahydro-1H-indole-2-carboxylic acid of formula (2) having (2S, 3aS, 7aS) -configuration, and specific examples thereof include, for example, the optically active N-protected-octahydro-1H-indole-2-carboxylic acids exemplified above having the specific N-protecting groups as described above and a(2S, 3aS, 7aS)-configuration.
[0151] According to the present invention, the optically active N-protected-octahydro-1H-indole-2-carboxylate having (2R, 3aR, 7aR) configuration can also be obtained. Specific examples of the optically active N-protected-octahydro-1H-indole-2-carboxylic acid of formula (2) having a(2R, 3aR, 7aR) -configuration include, for example, those having the (2R, 3aR, 7aR)-configuration in place of the (2S, 3aS, 7aS) -configuration in the specific compounds exemplified above.
[0152] Optically active N-protected-octahydro-1H-indole-2-carboxylic acids of formula (2) produced in the present invention can be readily further converted to corresponding optically active octahydro-1H-indole-2-carboxylic acid by deprotecting, i.e. removal of the imino-protecting group represented by R 2 in a known manner or similar methods as disclosed in Protective Groups in Organic Synthesis, Greene, T. W. 3.sup.rd Edition, Wiley, the whole disclosure of which is incorporated herein by reference.
EXAMPLES
[0153] Hereinafter, the present invention will be set forth in detail with reference to Examples and the like; however, the present invention is by no means limited to these examples.
Reference Example 1
Production of a Mixture of Ethyl (2S, 3aS, 7aS)-octahydro-1H-indole-2-carboxylate and Ethyl (2R, 3aR, 7aR)-octahydro-1H-indole-2-carboxylate
[0154] To a solution of 65.0 g (343.5 mmol) of an ethyl indole-2-carboxylate in 514 g of ethanol charged in an autoclave were added 38.3 g of concentrated sulfuric acid and then 5 g of 5% rhodium-carbon (in terms of dried weight). The atmosphere in the sealed autoclave was substituted with nitrogen and the autoclave was subsequently charged with hydrogen at 0.4 MPa and the temperature was raised to 60° C. While keeping the inside of autoclave at a pressure of 0.4 MPa, the solution was agitated at 60° C. for 10 hours. After completion of reaction, the catalyst was removed by filtration, and then the solvent was removed by distillation. The concentrated residue thus obtained was added to cooled water, and thereafter the resultant mixture mixed with a 10% aqueous potassium carbonate solution to adjust the pH of the mixture to 7. Further, after the solution was set to pH 9 with a 10% aqueous potassium bicarbonate solution, the water phase was extracted with diethyl ether. The organic phase thus obtained was washed with a 15% aqueous sodium chloride solution, and then dried over magnesium sulfate. Thereafter, the magnesium sulfate was removed by filtration, and the solvent in the solution thus obtained was removed by distillation to yield 57.2 g of a mixture of ethyl (2S, 3aS, 7aS)-octahydro-1H-indole-2-carboxylate and ethyl (2R, 3aR, 7aR)-octahydro-1H-indole-2-carboxylate [56.4 g of the desired compounds are contained, 285.8 mmol (yield 83.2%)].
Reference Example 2
Production of a Mixture of Ethyl (2S, 3aS, 7aS)-N-benzyloxycarbonyl-octahydro-1H-indole-2-carboxylate and Ethyl (2R, 3aR, 7aR)-N-benzyloxycarbonyl-octahydro-1H-indole-2-carboxylate
[0155] In 38.8 g of ethyl acetate was dissolved 15.6 g (78.0 mmol) of the mixture of the enantiomers obtained in Reference Example 1. To the resulting solution were added 38.8 g of water and 15.5 g of potassium bicarbonate and mixed. To this solution cooled to 0° C. was dropped 15.0 g of benzyloxycarbonyl chloride over 1 hour. After the completion of dropping, the solution was raised to room temperature, and then agitated at room temperature for 4 hours to complete the reaction. After the completion of reaction, to the reaction mixture was added 40 g of ethyl acetate to separate the resultant solution. From the resulting organic phase the solvent was removed by distillation to obtain an oily mixture of ethyl (2S, 3aS, 7aS)-N-benzyloxycarbonyl-octahydro-1H-indole-2-carboxylate and ethyl (2R, 3aR, 7aR)-N-benzyloxy-carbonyl-octahydro-1H-indole-2-carboxylate. This oily mixture was purified using n-hexane/ethyl acetate (eluate of the volume ratio of 85:15) by silica gel column chromatography to yield 24.3 g of a mixture of ethyl (2S, 3aS, 7aS)-N-benzyloxycarbonyl-octahydro-1H-indole-2-carboxylate and ethyl (2R, 3aR, 7aR)-N-benzyloxycarbonyl-octahydro-1H-indole-2-carboxylate [contained pure compounds were 22.8 g, 68.8 mmol (yield 88.2%)].
Example 1
Production of (2S, 3aS, 7aS)-N-benzyloxycarbonyl-octahydro-1H-indole-2-carboxylic Acid
[0156] 15.1 g of dipotassium hydrogenphosphate were dissolved in 1000 g of water and then to the resulting solution was added phosphoric acid to prepare an aqueous buffer adjusted to pH 7.0.
[0157] 2.5 ml of the aqueous buffer, 40.7 mg of the mixture obtained in Reference Example 2, and 101 mg of a culture containing Esterase 160A189Y363term derived from Chromobacterium SC-YM-1 strain (this strain was originally deposited in National Institute of Bioscience and Human-Technology Agency of Industrial Science and Techonology as an asccession No. FERMP-14009 by the applicant on Dec. 9, 1993 and at present continuously deposited as an accession No. FERMBP-6703 under Budapest Treaty) prepared in accordance with the method described in Japanese Unexamined Patent Application Publication No. 7-213280 were placed in a reaction vessel, and the resulting mixture was agitated at 30° C. for 20 hours. A solution prepared by adding 2.5 ml of acetone to the reaction solution after agitation was analyzed with a high performance liquid chromatogram (a column of CHIRALCEL OJ-RH, 4.6 mmf×15 cm, 5 mm available from Daicel Chemical Industries, Ltd. was used), and the resultant (2S, 3aS, 7aS)-N-benzyloxycarbonyloctahydro-1H-indole-2-carboxylic acid was analyzed and it was found that the yield was 48.2% and the enantiomer excess was 99.7% e. e. or more (other enantiomers were not detected.).
Example 2
Production of (2S, 3aS, 7aS)-N-benzyloxycarbonyl-octahydro-1H-indole-2-carboxylic Acid
[0158] 13.3 g of dipotassium hydrogenphosphate was dissolved in 1.0 Kg of water and to the resulting solution was added 0.4 g of phosphoric acid to prepare an aqueous buffer adjusted to pH 8.0.
[0159] To this aqueous buffer were added 52.7 g (containing 51.2 g of pure compound, 154.5 mmol) of a racemic mixture obtained by the method as in Reference Example 2 and 50.7 g of a culture containing Esterase 160A189Y363term derived from Chromobacterium SC-YM-1 strain prepared in accordance with the method described in Japanese Unexamined Patent Application Publication No. 7-213280 and then the resulting mixture was agitated at 30° C. for 30 hours. During the reaction, 59.8 g of a 10% aqueous sodium carbonate solution was continuously added so that the solution was kept at pH 8.0. After the completion of reaction, the solution was adjusted to pH 2.2 by addition of 35% hydrochloric acid, and to this solution were added 25.4 g of celite and 150 g of ethyl acetate and then the resulting material was agitated for 0.5 hour. After insoluble matters were separated by filtering the suspension obtained by agitation, the filtrate solution thus obtained was adjusted to pH 10.5 using a 10% aqueous sodium hydroxide solution.
[0160] The resulting solution was separated into an oil phase and a water phase by phase separation.
[0161] To the water phase thus obtained was added 250 g of ethyl acetate and then extraction operation was carried out and separated into an oil phase and a water phase.
[0162] The oil phases thus obtained were combined and the resulting oil was dried over magnesium sulfate. Thereafter, the solvent was removed by distillation to yield 27.3 g of a colorless oily substance containing ethyl (2R, 3aR, 7aR)-N-benzyloxycarbonyloctahydro-1H-indole-2-carboxylate.
[0163] 25.8 g (77.7 mmol) of ethyl N-benzyloxycarbonyl-octahydro-1H-indole-2-carboxylate were contained in this oily substance, thus the yield was 50.3% and the enantiomer excess was 96.5% e.e.
[0164] To the water phase separated previously from the oil phase was added 250 g of ethyl acetate. Then, to the aqueous solution was added 35% hydrochloric acid to make the pH of the solution 2.0, and subsequently the oil phase and the water phase were separated.
[0165] To the water phase thus obtained was added 250 g of ethyl acetate and the solution was subjected to extraction, and subsequently to phase separation. The oil phases thus obtained were combined and the resulting oil was dried over magnesium sulfate. Then, the solvent was removed by distillation to obtain 24.6 g of a colorless amorphous material containing 23.2 g (76.3 mmol) of pure (2S, 3aS, 7aS)-N-benzyloxy-carbonyloctahydro-1H-indole-2-carboxylic acid.
[0166] (2S, 3aS, 7aS)-N-benzyloxycarbonyloctahydro-1H-indole-2-carboxylic acid was obtained in a yield of 49.4% and with an enantiomer excess of 99.8% e.e or more. The other enantiomer was not detected.
Reference Example 3
Production of a Mixture of Ethyl (2S, 3aS, 7aS)-N-tert-butoxycarbonyl-octahydro-1H-indole-2-carboxylate and ethyl (2R, 3aR, 7aR)-N-tert-butoxycarbonyl-octahydro-1H-indole-2-carboxylate
[0167] To a solution of 1.97 g (10.0 mmol) of the mixture of the enantiomers obtained in Reference Example 1 and 2.29 g of di-tert-butyldicarbonate in 9.9 g of toluene were added dropwise 1.11 g of triethylamine at 20° C. over 1 hour, and the solution was stirred for more than 12 hours at the temperature. Then the solution was washed with 1% hydrochloric acid, 5% sodium hydrogencarbonate and water. The separated oil phase was evaporated to give an oily mixture of ethyl (2S, 3aS, 7aS)-N-tert-butoxycarbonyl-octahydro-1H-indole-2-carboxylate and ethyl (2R, 3aR, 7aR)-N-tert-butoxycarbonyl-octahydro-1H-indole-2-carboxylate. This mixture was purified by silica gel column chromatography using an eluent of n-hexane/ethyl acetate(99/1, v/v) to obtain 2.77 g of mixture of ethyl (2S, 3aS, 7aS)-N-tert-butoxycarbonyl-octahydro-1H-indole-2-carboxylate and ethyl (2R, 3aR, 7aR)-N-tert-butoxycarbonyl-octahydro-1H-indole-2-carboxylate. (Yield 93.1%)
Example 3
Production of (2S, 3aS, 7aS)-N-tert-butyloxycarbonyl-octahydro-1H-indole-2-carboxylic Acid
[0168] 0.29 g of dipotassium hydrogenphosphate was dissolved in 20.0 g of water and a buffer solution of which pH was adjusted to pH 8.0 by adding phosphoric acid thereto was prepared.
[0169] To this aqueous buffer were added 1.00 g (3.36 mmol) of the racemic mixture obtained by the method as in Reference Example 2 and 10.0 g of a culture containing Esterase 160A189Y363term derived from Chromobacterium SC-YM-1 strain prepared in accordance with the method described in Japanese Unexamined Patent Application Publication No. 7-213280 and then the resulting mixture was agitated at 30° C. for 40 hours. During the reaction, 1.8 g of a 10% aqueous sodium carbonate solution was continuously added so that the solution was kept at pH 8.0. After the completion of reaction, the solution was adjusted to pH 10.5 by addition of 10% sodium carbonate. Settled mixture was separated into oil phase and water phase, and the water phase was extracted with 10 go of ethyl acetate, settled and separated and the extraction was repeated again. The combined oil phase was dried over magnesium sulfate and evaporated to give 0.42 g of pale brown oily substance containing (2R, 3aR, 7aR)-N-tert-butyloxycarbonyl-octahydro-1H-indole-2-carboxylic acid. The oily substance contained 0.39 g (1.30 mmol) of (2R, 3aR, 7aR)-N-tert-butyloxycarbonyl-octahydro-1H-indole-2-carboxylic acid, and the yield was 38.7% and 99.3% ee (the enatiomer excess was measured by High Performance Liquid Chromatography using two pieces of CHIRALCEL OJ-RH, 4.6 mmø×15 cm, 5 mm manufactured by Daicel Company, Limited.) Other isomer was not detected.
[0170] To the water phase separated previously from the oil phase was added 30 g of ethyl acetate. Then, to the aqueous solution was added 10% hydrochloric acid to make the pH of the solution 2.8, and subsequently the oil phase and the water phase were separated.
[0171] To the water phase thus obtained was added 30 g of ethyl acetate and the solution was extracted and subjected to phase-separation, and the extraction was repeated again. The combined oil phase was dried over anhydrous magnesium sulfate and evaporated to give 0.46 g of pale brown oily substance containing 0.41 g of (2S, 3aS, 7aS)-N-tert-butyloxycarbonyl-octahydro-1H-indole-2-carboxylic acid. (2S, 3aS, 7aS)-N-tert-butyloxycarbonyl-octahydro-1H-indole-2-carboxylic acid was obtained in a yield of 45.4% and 99.5% ee or more. The other enantiomer was not detected (The enatiomer excess was measured by High Performance Liquid Chromatography using two pieces of CHIRALCEL OJ-RH, 4.6 mmø×15 cm, 5 mm manufactured by Daicel Company, Limited.)
|
To provide an enzymatic resolution process for efficiently producing an optically active N-protected-octahydro-1H-indole-2-carboxylic acid denoted by the formula (2):
by using an enzyme capable of asymmetrically hydrolyzing the —CO 2 R 1 group in the formula (1)
wherein R 1 indicates an alkyl group having a carbon number of 1 to 4, R 2 indicates a protecting group of the imino group, and the carbon atoms marked with asterisks (*) indicate asymmetrical carbon atoms.
| 2
|
PRIORITY
[0001] This application claims priority to U.S. Provisional Application No. 62/364,131 filed on Jul. 19, 2016, which is hereby incorporated by reference herein for all purposes.
TECHNICAL FIELD
[0002] The present disclosure relates to power limiters and, in particular, switched mode power supplies (SMPS).
BACKGROUND
[0003] An SMPS actively regulates its output voltage by switching the output on and off in a duty cycle. The output of the SMPS may be given by the relative duration of the on and off portions of the duty cycle. This may be in contrast to linear power supplies, wherein power is dissipated in, for example, a transistor. SMPSs may be implemented as, for example, buck converters, boost converters, or buck-boost converters. An SMPS may regulate output voltage or current by switching ideal storage elements such as inductors and capacitors into and out of different electrical configurations. If a power source, an inductor, a switch, and the corresponding electrical ground are placed in series and the switch is driven by a square wave, the peak-to-peak voltage of the waveform measured across the switch can exceed the input voltage from the DC source. This is because the inductor responds to changes in current by inducing its own voltage to counter the change in current, and this voltage adds to the source voltage while the switch is open. If a diode-and-capacitor combination is placed in parallel to the switch, the peak voltage can be stored in the capacitor, and the capacitor can be used as a DC source with an output voltage greater than the DC voltage driving the circuit. This boost converter acts like a step-up transformer for DC signals. A buck-boost converter works in a similar manner, but yields an output voltage which is opposite in polarity to the input voltage. Other buck circuits exist to boost the average output current with a reduction of voltage. In an SMPS, the output current flow depends on the input power signal, the storage elements and circuit topologies used, and also on the modulation and duty cycle to drive the switching elements. The spectral density of these switching waveforms has energy concentrated at relatively high frequencies. As such, switching transients and ripple introduced onto the output waveforms can be filtered with a small LC filter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] FIG. 1 is an illustration of an example SMPS using an adaptive input power limiter, according to embodiments of the present disclosure.
[0005] FIG. 2 is an illustration of an example adaptive input power limiter within the context of an SMPS, according to embodiments of the present disclosure.
[0006] FIG. 3 illustrates a problem of potential overloads or short circuits addressed by embodiments of the present disclosure.
[0007] FIG. 4 illustrates a problem of potential overloads or short circuits when current limiters are used and addressed by embodiments of the present disclosure.
[0008] FIG. 5 illustrates example performance of an SMPS using an adaptive input power limiter, according to embodiments of the present disclosure.
[0009] FIG. 6 illustrates further example performance of SMPS 100 using an adaptive input power limited, according to embodiments of the present disclosure.
SUMMARY
[0010] Embodiments of the present disclosure include a power limiter. The power limiter may be for an SMPS. The power limiter may include an operational amplifier and a comparator circuit. The operational amplifier may be configured to receive an input voltage supplied to the SMPS as a first input and a reference voltage as a second input. The comparator circuit may be configured to receive an output of the operational amplifier, receive a current sense signal, and generate an output signal configured to control a power generator. In combination with any of the above embodiments, the output signal may be based on a comparison between the output of the operational amplifier and the current sense signal. In combination with any of the above embodiments, the output of the operational amplifier may be a current limit. In combination with any of the above embodiments, the comparator circuit may be further configured to generate the output signal based on a comparison between a set current limit and a measured current by comparing the output of the operational amplifier and the current sense signal. In combination with any of the above embodiments, the output signal may be configured to overwrite a feedback signal from output of the SMPS. In combination with any of the above embodiments, the output signal may be configured to overwrite a feedback signal from output of the SMPS. In combination with any of the above embodiments, the comparator circuit may be further configured to generate the output signal before reception of the feedback signal. In combination with any of the above embodiments, the operational amplifier and the comparator unit may be incorporated into a microcontroller. In combination with any of the above embodiments, the operational amplifier may be further configured to lower a current input limit as input voltage increases. In combination with any of the above embodiments, the operational amplifier may be further configured to lower a current input limit as input voltage increases according to a slope defined by one or more resistors connected between an input voltage source and the operational amplifier. In combination with any of the above embodiments, the operational amplifier may be further configured to maintain a current limit above zero based upon the reference voltage.
[0011] Also, embodiments of the present disclosure include an SMPS, including any of the power limiters of the above embodiments. The SMPS may include a pulse-width modulation power generator circuit configured to produce an output voltage based on a duty cycle of a pulse-width modulation output. The comparator circuit may be configured to receive a current sense signal based on output of the pulse-width modulation power generator circuit.
[0012] Furthermore, embodiments of the present disclosure include a microcontroller including any of the power limiters or SMPSs of the above embodiments.
[0013] In addition, embodiments of the present disclosure include methods performed by any of the power limiters, SMPSs, or microcontrollers of the above embodiments.
DETAILED DESCRIPTION
[0014] FIG. 1 is an illustration of an example SMPS 100 using an adaptive input power limiter, according to embodiments of the present disclosure.
[0015] SMPS 100 may include a variable input power source 102 , a power conversion stage 104 , SMPS control 110 , and an adaptive power limiting function 108 . Each of such elements may be implemented in any suitable combination of analog or digital circuitry, including instructions for execution by a processor. Power source 102 may include a voltage or current source. Power conversion stage 104 may switch power on and off according to a duty cycle to generate output power 106 . Output power 106 may be fed back to SMPS control 110 in order to determine whether to adjust the power conversion stage 104 so as to maintain an expected level of output power 106 . SMPS control 110 may specify the duty cycle and other operational parameters of SMPS 100 .
[0016] SMPS 100 may prevent power conversion that exceeds the specified design by measuring output of the converter where the power is delivered, such as output power 106 . In a fixed output voltage conversion design, the limit is placed on the delivered output current, while for a fixed output current conversion design, the limit is placed on the measured output voltage. Thus, while SMPS 100 is illustrated in FIG. 1 and FIG. 2 as measuring and evaluating current with respect to output voltage of SMPS 100 , SMPS 100 might be implemented instead as measuring and evaluating voltage with respect to output current of SMPS 100 .
[0017] Limiting techniques may be used to prevent damage or unwanted operation, even when the converted power is within specifications. Such a case can happen when the input voltage is smaller than the rated value. An undervoltage lockout will stop the conversion until the input voltage is within specified levels. Another case where the power conversion can be within specifications is an output overvoltage. In such a case, power conversion enters a shutdown state to protect the load from irreversible damage.
[0018] In one embodiment, adaptive power limiting function 108 may implement adaptive input power limits for SMPS 100 . Embodiments of adaptive power limiting function 108 are shown in more detail in FIG. 2 .
[0019] As discussed above, in SMPS 100 a variable input power source 102 may provide variable input voltage to SMPS 100 . When there is variable input voltage, an overload or short circuit condition may arise when output power 106 rises too high.
[0020] FIG. 3 illustrates a problem of possible overloads or short circuits with other SMPSs. For example, an offline 20 W flyback SMPS was tested with different input voltages and the output current was varied to simulate an overload. Current and power values where the output voltage dropped by 0.5V with respect to the desired value are plotted in FIG. 3 . 90, 100, and 110 volts AC inputs are shown as reference. Response with respect to current and power output are shown in FIG. 3 . Another input value, 170 volts AC, not shown in FIG. 3 , produced an 8 A output and 93 W before the output voltage decreased 0.5V. Other solutions may prevent such overloading by adding an input current limit, using a digital-to-analog converter (DAC). However, a further problem arises because such solutions are based upon a calculated input voltage. The input voltage may change when, for example, a variable input voltage or power source is used such as an SMPS 100 or when a voltage or power source, otherwise assumed to be constant, degrades, changes, or is affected by noise or other ambient conditions and does not provide the assumed voltage source. FIG. 4 illustrates such a problem of possible overloads or short circuits with other SMPSs that use current limiting. A similar test as was performed for FIG. 3 to determine at what output current and power that the output voltage would drop by 0.5 volts while a current limit is calculated to limit output power to 31 W at 90 volts AC. As shown in FIG. 4 , even while the intended power limit was approximately functional at the desired set point of 30 W at 90 volts AC, as the input voltage increased the output current and power continued to rise significantly, which would still cause overload and short circuit problems.
[0021] These other SMPS systems often determine a fixed threshold reference on inductor current that will take over the control loop and will end the pulse earlier. The fixed threshold level is often implemented with a comparator with a fixed limit level or an error signal. A comparator may stop the PWM pulse earlier if the threshold level is passed, or another comparator with a higher, fixed threshold level may stop the IC for a limited time to prevent component damage.
[0022] These other SMPS systems may utilize a fixed duty-cycle limit to prevent damage. However, this works only for a fixed input voltage and fixed output voltage converter. Furthermore, the converter may have to be calculated exactly to limit the desired power limit to the duty cycle and still work properly in normal operation conditions. Once designed, the limit is not configurable. In such cases, output power rises with the increase of the input voltage. In such a solution using only a maximum duty cycle limit, there is no current limit from the primary cycle. At 160 VAC input, the load can take 93 W of power from the SMPS without losing output regulation; thus, the SMPS components will fail.
[0023] These other SMPS systems may utilize a fixed primary-peak current limit. However, in these systems when the input voltage of the converter is variable for the same power transfer, the current signal will become smaller. This may result in a higher power transfer before reaching the set limit. Because the limit is fixed, configuration is not possible.
[0024] These other SMPS systems may utilize an output current limit. However, this technique becomes very expensive in isolated designs as having multiple signals pass through the isolation barrier can become very costly. As the limit is fixed, configuration is not possible. These results prove that the classic limit approach works only if there is direct access to the output current signal. It does not work with a system with large input variations and isolation needs.
[0025] Returning to FIG. 1 , SMPS 100 may be configured to address aspects of the shortcomings of systems whose performance is shown in FIGS. 3 and 4 . SMPS 100 may be configured to limit the total power conversion produced as an output. Furthermore, SMPS 100 may be configured to prevent damage to a load connected to output of SMPS 100 . In addition, SMPS 100 may be configured to prevent high short-circuit impulses. Also, SMPS 100 may be configured to prevent transformer core saturation. In one embodiment, SMPS 100 may be configured to provide user control over power limits.
[0026] In one embodiment, SMPS 100 can be configured to adapt the limit of the output power of SMPS 100 while still giving the user of SMPS 100 the ability to change the limit. In another embodiment, the limit, after being set, may apply to variable input voltages. SMPS 100 may be configured to adapt to a wide variety of input voltages from variable input power source 102 . The variations in power may be by design, or may arise from degradation, malfunction, or noise affecting the source. The output power may be maintained below a set limit. The adaptable limit of the output power of SMPS 100 may be implemented with circuitry, including hardware or software executed by a microcontroller.
[0027] Adaptive power limiting function 108 may be communicatively coupled to variable input power source 102 and to SMPS control 110 . Thus, adaptive power limiting function 108 may be placed on the primary side of SMPS 100 and of the converter (power conversion stage 104 ) thereof. Accordingly, adaptive power limiting function 108 may be able to set, change, or affect the duty-cycle values controlled by SMPS control 110 . This may include the maximum duty-cycle limit set therein. In one embodiment, this limit may adapt to the input voltage variation. In a further embodiment, this may be implemented by an inverse proportional function implemented in adaptive power limiting function 108 . Consequently, adaptive power limiting function 108 may limit the maximum output power delivery in output power 106 from the primary of the power conversion stage 104 by limiting the amount of primary current into power conversion stage 104 based on the voltage from variable input power source 102 . When output power 106 reaches sufficient limits, further, higher output voltage feedback will be ignored.
[0028] An adaptable software limit may be implemented by an ADC and a DAC to change the set peak current limit. An internal set of limits is defined and attributed to a certain range of input voltages. The ADC measures a proportion of the input voltage and stores it in the memory. After each acquisition, the value is compared to the input voltage attributed in the limit array and the peak current limit is updated in the DAC. This solution is feasible when the input voltage changes are slow.
[0029] A hardware-based implementation may free a processor core from other SMPS-related tasks. The implementation may change the current limit inversely proportional to the input voltage change using one internal op-amp and one DAC. A resistor divider scales down the rectified input voltage and the op-amp is used to invert the signal, so when the input voltage rises, the current limit will adapt and fall. The DAC may be set as an op-amp positive input to raise the inverted signal over the 0V line. This signal may be compared with the current from the transformer primary and trigger a falling event on the pulse-width modulation generation circuit when the current reaches the set limit. The limit trigger may also be used to implement a shutdown or other functions in the circuit.
[0030] FIG. 2 is an illustration of an example adaptive input power limiter within the context of an SMPS, according to embodiments of the present disclosure. Furthermore, the adaptive input power limiter may be implemented in a microcontroller 204 , such as a PIC microcontroller unit. In various embodiments, the adaptive input power limiter may be implemented in any other suitable electronic device.
[0031] Operation of adaptive power limiting function 108 may be performed in part by an op-amp 214 . Op-amp 214 may receive as one input a voltage reference values, VREF. The value of VREF may be provided by a DAC 212 and may be output from elsewhere in SMPS 100 , such as another component of microcontroller 204 . Op-amp 214 may receive as another input a proportion of the input voltage 202 applied to SMPS 100 . The input voltage, VIN 202 , may be provided by variable input power source 102 . In one embodiment, VIN 202 may be passed to op-amp 214 through a resistor network. The resistor network may include resistors 206 , 208 , 210 denoted R 1 , R 2 , R 3 . VIN 202 may be connected to resistor 206 , which may be connected to resistor 208 and op-amp 214 . Resistor 208 may be connected to ground. Resistor 210 may be connected between the output of op-amp 214 and the input of op-amp 214 as well as resistors 206 , 208 .
[0032] In one embodiment, op-amp 214 may be implemented within microcontroller 204 . In another embodiment, op-amp 214 may be implemented separately from microcontroller 204 . In yet another embodiment, resistors 206 , 208 , 210 may be implemented outside microcontroller 204 .
[0033] Output of op-amp 214 may be shown as OPAMP OUT 216 in FIG. 2 . OPAMP OUT 216 may be also denoted as VINV. Op-amp 214 may amplify and invert VIN 202 to product VINV. VINV may be passed as an input to a comparator 218 . Comparator 218 may be implemented in any suitable combination of analog or digital circuitry, such as with an op-amp. Comparator 218 may accept as another input output of a current sensor, ISENSE 220 . The current sensor may be implemented in any suitable combination of analog or digital circuitry. ISENSE 220 may represent the current produced as part of feedback received through output power 106 .
[0034] The output of comparator 218 may be passed to a complementary output generator (COG) 222 . COG 222 may be implemented in any suitable combination of analog or digital circuitry. COG 222 may be configured to, based upon voltage signal input, issue a drive signal representing the duty cycle signal that will drive the switched-mode operation of SMPS 100 . COG 222 may include inputs for rising event (RE) and falling event (FE) signals. If input is connected to RE input, COG 222 may issue the duty cycle signal upon rising of its input. If input is connected to FE input, COG 222 may issue the duty cycle signal upon falling of its input. COG 222 may implement a driver of the duty-cycle signal.
[0035] As shown, ISENSE 220 illustrates current as issued with respect to output power 106 . ISENSE illustrates that the current is zero during the off portion of the duty cycle, rising quickly to a base level when the on portion of the duty cycle is initiated, and rising thereafter until the off portion of the duty cycle.
[0036] Resistor 206 may limit the current sampled from the input. Op-amp 214 and resistor 210 may combine to implement an inverting function to VIN 202 . Resistor 210 may dictate the intervening proportion. VREF 212 rises the output function of op-amp 214 above the 0V with the set value of VREF 212 so that the resulting function 216 can be used by comparator 218 . Comparator 218 may provide a falling event to COG 222 when the output of op-amp 214 is compared with ISENSE 220 . This may happen before the output feedback regulation signal from 106 provides a falling event on COG 222 and overwrite the feedback falling event with an early falling event from comparator 218 .
[0037] When op-amp 214 takes a portion of VIN 202 and inverses it, as VIN increases, OPAMP OUT 216 decreases. Accordingly, when voltage rises to otherwise dangerous levels, such as higher than 90V, op-amp 214 would otherwise go negative except for the shift provided by VREF 212 . VREF 212 may thus cause OPAMP OUT 216 to stay above zero volts. Furthermore, a user or designer of SMPS 100 may set VREF according to desirable outputs. As shown in FIG. 2 , at a 90V level of VIN 202 , OPAMP OUT 216 may be at 1.9V. After rising to, for example, 360V of VIN 202 , OPAMP OUT 216 may be at 1.5V. OPAMP OUT 216 may represent or be proportional to an effective current limit for SMPS 100 . Thus, as VIN 202 rises, the current limit of SMPS 100 may decrease. The slopes and values of OPAMP OUT 216 may be dependent upon resistor and VREF values, discussed further below.
[0038] Accordingly, when the decreased current limit is reached, as ascertained by comparator 218 , the output drive signal is stopped and thus the output power is lessened. COG 222 may drive a pulse width modulated square wave signal, the width of which powers output of SMPS 100 .
[0039] As a result, SMPS 100 may implement a direct duty-cycle limit on the driver (COG 222 ). This limit, to the outside of SMPS 100 , may be seen as a maximum power limitation. Moreover, this power limitation may be independent to adapt with the input voltage variation.
[0040] A user or designer of SMPS 100 may allow users to change the output power limit. As op-amp 214 generates an inverse-proportional waveform to the input voltage, the proportionality may be given by the relationship between resistors 206 , 208 , 210 . This relationship may be given by:
[0000]
V
INV
=
V
REF
-
R
3
×
(
V
I
N
R
1
-
V
REF
R
2
)
[0041] This relationship expresses how resistors 206 , 208 , 210 and op-amp 204 are used to generate a waveform inversely-proportional to VIN 202 , so when the output voltage rises the limit will drop and adjust. In one example, resistor 206 may be selected as 1 MOhm to limit the current that goes to the rest of the adaptive limit circuit, resistor 208 may be selected as 51 KOhm, resistor 210 may be selected as 1.5 KOhm, and VREF 212 can be set to 2V. Thus, the set limit of VINV will be 1.9V when the rectified input voltage is 90 VDC, and 1.5V when the rectified input voltage is 360 VDC.
[0042] The limits used in SMPS 100 may be automatically changed or utilized in various situations. For example, a designer or user of SMPS 100 may control the maximum power delivery at any moment during runtime. A user may be notified or the power limit further reduced after multiple instances of limiting operation. A time limit may be applied to the maximum allowed power conversion. For example, an 100 W converter can be set to deliver a maximum 80 W after five years of operation to extend the lifetime of the product and prevent wear and tear. Furthermore, a user may use the same instance of SMPS 100 for multiple applications, wherein the maximum allowed power is adjusted on the basis of the application. For example, the user may use a 100 W/12V converter to power a 100 W load, a 60 W load and a 20 W load separately without the need of having three separate converters. Furthermore, the necessary protections and functions will work correctly in all instances. SMPS Control 110 and Adaptive Power Limiting Function 108 , though implementable in a microcontroller, need not use the microcontroller core. Accordingly, logic may be installed to detect triggering of the limiting operation to identify when the power delivery is at limit, without compromising the safety of the conversion.
[0043] FIG. 5 illustrates example performance of SMPS 100 using an adaptive input power limiter, according to embodiments of the present disclosure. A set limit for 30 W may be set. The minimum and maximum values of testing are 30 W and 31.5 W, respectively. As the input voltage rises, the output power is nonetheless controlled.
[0044] FIG. 6 illustrates further example performance of SMPS 100 using an adaptive input power limiter, according to embodiments of the present disclosure. In particular, FIG. 6 illustrates current waveforms such as ISENSE 220 under different input voltage VIN 202 . In (a), the input voltage is 90V, and in (b) the input voltage is 130V. As the input voltage rises from (a) to (b), the current limit adapts and falls from 2 A to 1.6 A based upon the operation of SMPS 100 .
[0045] Although embodiments have been described in detail with particular reference to figures and examples, one of skill in the art would recognize that variations, additions, and modifications can be effected within the spirit and scope of the present disclosure.
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A power limiter for a switched mode power supply includes an operational amplifier and a comparator circuit. The operational amplifier is configured to receive an input voltage supplied to the SMPS as a first input and a reference voltage as a second input. The comparator circuit is configured to receive an output of the operational amplifier, receive a current sense signal, and generate an output signal configured to control a power generator. The output signal is based on a comparison between the output of the operational amplifier and the current sense signal.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This is a U.S. national stage of application No. PCT/EP2012/074207 filed 3 Dec. 2012. Priority is claimed on European Application No. 11195875 filed 28 Dec. 2011, the content of which is incorporated herein by reference in its entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a hardware device and a method for producing the hardware device, such as a manipulation-proof hardware chip in the style of a trusted platform module.
[0004] 2. Description of the Related Art
[0005] A trusted platform module (TPM) is understood to mean a chip that is fabricated in accordance with prescribed specifications from the trusted computing group (TCG). In this case, the TCG provides open standards for trusted computing platforms, a trusted platform being understood to mean a chip or a computer platform that reliably behaves in a predefined manner for the prescribed purpose.
[0006] In this case, a corresponding piece of TPM hardware implements security functions as an integrated circuit or chip and can be used in various devices, such as PCs, notebooks, PDAs, mobile telephones or network devices in networks. In this case, a TPM comprises an explicit cryptographic key that can be used to identify the computer in which the TPM is used. In standard applications, such as for personal computers that are equipped with TPM modules, the computation speed of the TPM is usually insignificant. Cryptographic coprocessors in industrial applications also usually have no realtime capability.
[0007] However, it is desirable, in areas with realtime requirements, such as automation engineering, also to provide reliable realtime-compatible modules that implement cryptographic applications, in particular. In this case, it has been particularly difficult in the past to specify such hardware devices reliably.
SUMMARY OF THE INVENTION
[0008] It is therefore an object of the present invention to provide an improved method for producing a corresponding hardware device.
[0009] This and other objects and advantages are achieved in accordance with the invention by providing a method for producing a hardware device, particularly a trusted platform module, for executing at least one, in particular cryptographic, algorithm. In this case, the hardware device preferably has realtime capability and corresponds to a realtime class, for example, and the method comprises providing at least one algorithm in the form of program code, determining a maximum or longest execution time for the algorithm, fabricating a tamper-proof hardware device that is set up to execute the algorithm, and allocating the hardware device to a realtime class based on the maximum execution time.
[0010] The hardware device, which can also be referred to as a chip, IC circuit or hardware chip, preferably comprises a trusted platform module in this case. The TPM module is embodied in accordance with the TCG specifications in this case. However, it is also possible for the hardware device to be organized in accordance with different or similar specifications. The respective maximum or longest execution time for the algorithm, which may be available in a program code such as C or in other programming languages, for example, is indicated in clock cycles or else in the number of floating point operations that are necessary for performing the algorithm.
[0011] The allocation to a realtime class, e.g., according to the classification of the IAONA or according to IEC-61784-2, ensures that the hardware device always performs the algorithm within the maximum execution time for the implemented algorithm. Hence, realtime applications are possible. As a result, the hardware device is particularly suitable for use in process automations or industrial automation systems.
[0012] Suitable algorithms for the hardware device are encryption or authentication functions and secure cryptographic key storage operations, for example. When the algorithm is selected or organized in the form of program codes, all the possible execution paths that can arise during the handling of the algorithm are preferably detected and recorded. The execution paths can be calculated, established or determined. The algorithm, which implements particularly a cryptographic function, can be customized for the possible execution paths, i.e., program passes, in the actual design phase, for example in the form of UML modeling operations using clocks or timers.
[0013] The method preferably also comprises the detection, calculation, establishment or determination of the execution times or the calculation times for all the execution paths for the algorithm. Comparison of the execution times, for example, measured from the necessary clock cycles, allows the maximum required time for performing the algorithm to be determined. This maximum or longest execution time is used for classifying the hardware chip or the hardware device that is produced with tamper-proofing.
[0014] In this case, the hardware chip can be implemented as an FPGA or ASIC, for example. In this respect, a realtime-compatible hardware device with cryptographic functions is obtained that is suitable particularly for use in automation networks. A user of the relevant hardware knows reliably how quickly he can expect a response from the module to a request, for example.
[0015] In one embodiment, the method may also comprise: prescription of a maximum data length for an input parameter, with the algorithm being executed based on the input parameter. Examples of input parameters are cryptographic keys, which have their length prescribed in bits or bytes. This allows a standardized and limited maximum execution time to be attained in the design and production phase for the hardware device. The maximum execution time is also referred to as WCET (worst case execution time).
[0016] The method preferably comprises: compilation of the program code using a nonoptimizing compiler. By way of example, a WCET-optimizing compiler is used, rather than, as otherwise customary, ACET/OCET-optimizing compilers (ACET=average case execution time, OCET=optimal case execution time). The compiled program code is then implemented in hardware, as a result of which the program logic is available as hardware. In order to confirm or verify the maximum or longest execution time for the algorithm, it is possible to use a WCET analysis tool. WCET is understood to mean the worst case execution time.
[0017] The method for producing a hardware device can be extended such that a series of hardware chips is produced, and each hardware chip is allocated to a realtime class. By way of example, hardware chips having prescribable realtime specifications can be produced that can be used for a prescribed application environment. In the case of hardware chips allocated to a realtime class, the algorithm is executed within the maximum execution time, which is reliably indicated to the user of the hardware device by the realtime classification.
[0018] By way of example, it is possible for the hardware chips in a respective series to execute a prescribed algorithm and for the hardware chips in different series to execute different algorithms. By way of example, in this case it is possible to implement algorithms that implement a method for hash value calculation, such as SHA-1, SHA-256, symmetric encryption methods, such as DES, 2DES, ABS. asymmetric encryption methods, such as RSA, ECDSA, or a method for generating a random number.
[0019] In addition, a trusted platform module is proposed that is produced according to a method as described above. The trusted platform module can be used in a computer device, such as a PC, or in devices of an automation system.
[0020] Furthermore, a computer program product is proposed that prompts the performance of the method as explained above for producing a hardware device at least to some extent on one or more program-controlled devices.
[0021] A computer program product such as a computer program means can be provided or supplied as storage medium, such as a memory card, USB stick, CD-ROM, DVD, or else in the form of a downloadable file, by a server in a network, for example. This can be effected in a wireless communication network, for example, by the transmission of an appropriate file with the computer program product or the computer program means. A suitable program-controlled device is particularly a program-controlled design system for integrated circuits.
[0022] Further possible implementations of the invention also comprise combinations that are not explicitly cited for features or embodiments of the method or of a hardware device that are described above or below for the exemplary embodiments. In this case, a person skilled in the art will also add or modify single aspects as improvements or additions to the respective basic form of the invention.
[0023] Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims. It should be further understood that the drawings are not necessarily drawn to scale and that, unless otherwise indicated, they are merely intended to conceptually illustrate the structures and procedures described herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] The properties, features and advantages of this invention that are described above and also the manner in which these are achieved will become clearer and more distinctly comprehensible in connection with the description below of the exemplary embodiments, which are explained in more detail in connection with the drawings, in which:
[0025] FIG. 1 shows a schematic illustration of realtime communication with a first embodiment of a hardware device;
[0026] FIG. 2 shows a schematic illustration of an execution time distribution for an algorithm for implementation in a hardware device;
[0027] FIG. 3 shows a schematic illustration of an embodiment of a challenge/response arrangement with a trusted platform module as hardware device;
[0028] FIG. 4 shows a schematic flowchart to explain an embodiment of a method for producing a hardware device;
[0029] FIG. 5 shows a portion of a schematic flowchart to explain a further embodiment of a method for producing a hardware device; and
[0030] FIG. 6 shows a schematic illustration of a portion of a program code to explain execution path determination.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0031] In the figures, elements that are the same or have the same function have been provided with the same reference symbols, unless stated otherwise.
[0032] Realtime-compatible hardware devices that are set up in the style of trusted platform modules provide cryptographic functions for access control, for encryption/decryption and for authentication in real time. A suitable realtime application is, in particular, an automation system, where automation devices are equipped with appropriate TPMs and communicate with one another via expansively ramified communication networks, in particular open networks. In this case, it is particularly desirable for the TPM to be provided as a realtime application.
[0033] In a standard challenge/response arrangement, a master device 2 sends a request message RQ to the TP module or the tamper-proof hardware device 1 , as shown schematically in FIG. 1 . This occurs at the time to. In this case, the hardware device 1 is produced using a method as described below. The TP module 1 is designed particularly according to TCG specifications in this case. That is, an endorsement key is explicitly allocated, the private portion of the key being stored in the TPM and not being readable. A storage route key is stored, as well as an attestation identity key. In addition, a secure random number generator is implemented in the trusted platform module 1 . Furthermore, security functions, such as sealing, relocation, protection of cryptographic keys, certification by attestation methods, such as privacy CA or direct anonymous attestation may be existent.
[0034] A prevalent algorithm that may be available in the form of a computer program or program code is the calculation of a hash value, such as HMAC-SHA1. This is indicated by way of example in FIG. 1 . At the time t 0 , the master device 2 sends a request message RQ (Request) via a suitable communication network, which may be the Internet, for example, or else wireless network connections based on a known protocol to the hardware device 1 , which is embodied as a trusted platform module. In this case, the transmitted data comprise a header H, a trailer T and random request data, which are also referred to as random challenge RC. The request RQ is detected by the TPM at the time t 1 .
[0035] For this random challenge RC, the hardware device 1 calculates a challenge response CR=HMAC-SHA1 (RC, SS). This involves the use of a shared password or shared secret SS.
[0036] Following the calculation at the time t 2 , the TPM 1 sends a request response or challenge response CR. Again, the transmitted data comprise a header H and a trailer T. At the time t 3 , the master device 2 receives the response message CR.
[0037] The timing is shown in FIG. 1 in an orientation from top to bottom. Particularly in the case of the transmission in open networks, such as the Internet, realtime calculation, i.e., delivery of the challenge response CR within a prescribed time, is necessary. The trusted platform module 1 shown is implemented as a realtime-compatible trusted platform module. That is, the handling time or execution time for the algorithm that performs the crypto function, for example, the calculation of the hash, is prescribed deterministically and by the hardware. In the example shown, the longest or maximal execution time for producing the response CR is t 2 −t 1 . It is also possible to refer to the WCET=t 2 −t 1 .
[0038] In order to meet the realtime requirement, allowance is made for the trusted platform module during the design and modeling, for example, by unified modeling language (UML), and the production of the trusted platform module, as explained in more detail below. The trusted platform module 1 is therefore provided with a specification that demonstrates the realtime capability of the TPM, and it can therefore be allocated to a realtime class. It is also possible to refer to the trusted platform module 1 produced providing a particular quality of service (QoS) and therefore being able to be used in an environment that presupposes hardware and software with realtime capability.
[0039] An advantage of realtime-compatible trusted platform modules or cryptographic modules or hardware chips is that they can be used particularly beneficially in automation engineering. The realtime requirements of the TPM that are met mean that the latter are able to replace currently standard physical security mechanisms between the components used, which means that the use of these realtime-compatible trusted platform modules is advantageous particularly in open networks.
[0040] Realtime requirement is subsequently understood to mean that a deterministic execution time for a prescribed algorithm, such as a cryptographic algorithm, occurs in a prescribed context. Under all circumstances, the prescribed maximum execution time, such as the delivery of a challenge response, is ensured, as indicated in FIG. 1 . Usually, realtime applications are also understood to mean calculations that occur particularly quickly, i.e., with a good level of performance. The indication of a realtime class for the trusted platform module allows the respective application environments to safely use the deterministic calculation of algorithms for making calculations.
[0041] In order to explain execution time distributions for algorithms, an execution time distribution D is plotted over time by way of example in FIG. 2 . Usually, an algorithm is calculated or executed based on an input parameter. In this respect, a different execution time may arise for various passes of the algorithm or of the handling by a piece of hardware. In this case, FIG. 2 shows a distribution of execution times for an algorithm that is not specified in more detail between a lower timing bound LTB and an upper timing bound UTB. By way of example, this may be the provision of a random number, a crypto algorithm, hash algorithm or other calculations that are necessary in trusted platform modules.
[0042] The distribution is irregularly scattered between LTB and UTB. The possible execution times are situated between BCET, a best case execution time, which is relatively short, and the worst case execution time WCET. The possible execution times are denoted by PET. In addition, a minimum measured execution time MLET and a maximum measured execution time MXET are indicated.
[0043] The indication and classification of a trusted platform module into a realtime class require the maximum or longest execution time WCET to be determined for the implemented hardware that maps the program logic of the algorithm. The influencing factors for the WCET are the program logic and the conversion to an appropriate machine code. Furthermore, the WCET is dependent on the architecture and clock frequency of the hardware used, and also the size or length of the input data is a factor that influences the WCET.
[0044] The algorithm to be implemented in the trusted platform module is presented in the style of program flowcharts according to DIN 66001 or other control flow graphs using UML, for example. Program flowcharts can be used to specify execution paths within the programs that have different lengths. In particular, symmetric and asymmetric cryptography algorithms, hash algorithms and random number generators are considered below. These are usually implemented in trusted platform modules.
[0045] In particular, ASICs or FPGAs are suitable as hardware implementation. An application-specific integrated circuit (ASIC) is realized as an integrated circuit, with operation now being practically unmanipulable. In this case, ASICs can be equipped with memories, microprocessors and the like as a system on a chip (SoC).
[0046] Field programmable gate arrays (FPGAs) can likewise be used to realize tamper-proof hardware devices such as trusted platform modules.
[0047] During the production of the trusted platform module, the size or data length of the input data is now stipulated to obtain a deterministic calculation time or to obtain a WCET. By way of example, data based on the Profinet standard in the form of a datagram (as indicated in FIG. 1 ) can be used. The volume of data in a Profinet datagram, such as with a header and a trailer and also respective data, can therefore be stipulated from the outset. As a result, it is possible for the execution time for all the paths in the program code to be detected during the program flow. In this case, it is also possible to detect error situations. As a result, the maximum execution time is determined to be the longest of all the possible path execution times. It is also possible to refer to static analysis of the program execution.
[0048] The maximum execution time is then determined from the number of necessary clock cycles for the longest execution path, for example. Alternatively or in addition, it is also possible to use methods such as Parse-tree-based methods or execution time modeling operations.
[0049] Particularly in the case of the processing of cryptographic keys or initialization data as input parameters for the algorithm, the data length, such as in the number of bytes or bits, is firmly prescribed, as a result of which it is possible to reliably determine a maximum execution time.
[0050] FIG. 3 shows a schematic illustration of an embodiment of a challenge/response arrangement 100 with a trusted platform module 1 as hardware device.
[0051] FIGS. 4 , 5 and 6 show embodiments and portions of a flowchart to explain a production method for the trusted platform module 1 . The aim of the production method is particularly, as already indicated in FIG. 1 , to provide a computer device, such as an automation device 10 , that is equipped with a trusted platform module 1 that has realtime capability. In this case, the trusted platform module 1 comprises a memory 11 for cryptographic keys of prescribed length. A master device 2 sends a request RQ and, following deterministic calculation of the response RP by the trusted platform module 1 , receives a response. This makes it possible to ensure that the automation device 10 is part of the associated automation network, for example, and proves its identity to the master device 2 in good time.
[0052] In order to produce the trusted platform module 1 in a reliable manner, a first step S 1 of the production method involves at least one algorithm, such as an algorithm for calculating a hash value or a random number generator or a symmetric or asymmetric encryption algorithm, being indicated. The algorithm is provided as program execution code. By way of example, FIG. 6 indicates a portion of an exemplary algorithm 3 . It is also possible to produce hardware devices that realize a plurality of algorithms. Step S 1 gives consideration to the case in which only one exemplary algorithm 3 is provided.
[0053] In the subsequent step S 2 , the maximum or longest execution time for the algorithm 3 is determined. Factors that may be cited that influence the longest or maximum execution time for the prescribed algorithm 3 are, in particular, prescribed input parameters, such as crypto parameters, key length, algorithm and the like. The parameters that are output by the algorithm and also prescribed reactions from the algorithm in the event of an error are also stipulated. By way of example, access to the cryptographic key in the memory 11 of the trusted platform module 1 also involves concomitant determination of the access time by the loading software or function used. The type of memory and the length of the key can therefore be indicated deterministically, as a result of which it is possible for the longest or maximum execution time WCET to be determined on the basis of these factors.
[0054] In addition, as indicated in FIG. 5 , a step S 21 involves detection of all the possible execution paths for the algorithm being performed. This means that an algorithm that is presented as program code or UML, for example, is analyzed such that all the possible execution paths are known. Next, all the possible execution times for the detected execution paths for the algorithm 3 are measured or calculated in step S 22 . The execution time is indicated in a number of floating point calculations or else clock cycles, for example.
[0055] Using the example of the algorithm that is shown in FIG. 6 , possible loop passes are started in an outer loop N, for example, and N passes are likewise started in the inner loop, which is dependent on the sequential parameter J. Overall, (N+1)N/2 executions arise in the program section between “begin” and “end”. In the case of more complex algorithms, for example, for calculating hash values or symmetric or asymmetric crypto algorithms such as DES, AES, RSA or ECDSA, a similar number of execution paths that can be considered in each case is obtained. The result obtained is a maximum execution time WCET for the algorithm to be implemented, said execution time corresponding to the longest execution path.
[0056] Next, the algorithm is implemented as a tamper-proof hardware device. This means particularly a trusted platform module, such as a chip and an ASIC. Particularly a trusted platform module that is implemented as an ASIC cannot be changed again following fabrication. In this respect, the deterministic maximum execution time WCET is stipulated by the production process in method steps S 1 to S 3 . Next, the manufacturer can specify a range for the respective clock frequency, depending on the technology used. On the basis of the clock frequency for the trusted platform module as an ASIC, it is possible to indicate the maximum execution time WCET in milliseconds or nanoseconds, for example. In this respect, the manufacturer is able to classify the trusted platform module produced into a realtime class. This is done in step S 4 based on the deterministic maximum execution time for the algorithm implemented in the trusted platform module, as defined by method steps S 1 to S 3 .
[0057] In this case, it is possible to produce different types of trusted platform modules suitable for different realtime requirements. During operation with the user, a trusted platform module is then chosen from a prescribed realtime class that complies with the area of application. If a trusted platform module is used in a sensor network, for example, with the sensors delivering sensor signals to a monitoring device only rarely, it is sufficient to use slow trusted platform modules in a realtime class that corresponds to a comparatively high WCET, for example.
[0058] It is also possible to implement the hardware chip or the trusted platform module 1 as a semi-programmable FPGA. By way of example, in that case an FPGA as a TPM can be customized further by the user in respect of the realtime requirements. By way of example, the cryptographic functions, clock frequencies, the input and output width or the internal memory 11 used can be stipulated. Nevertheless, it is possible to stipulate a deterministic maximum execution time via the classification during production into realtime classes.
[0059] In addition or as an alternative to the proposed measures for deterministically stipulating a realtime requirement for a trusted platform module, an initial key may be stipulated as what is known as a trust anchor on the trusted platform module itself with access protection. The cryptographic keys derived therefrom can then be stored permanently or in a volatile manner on other storage media in the appliance into which a trusted platform module is inserted. This means that not all the necessary cryptographic keys need to be stored within the TPM. For decrypting the data compiled outside, the TPM is then also used for determining the WCET.
[0060] Particularly the calculation of symmetric algorithms is always the same regardless of the input data and the keys, which means that there is a good deterministic and reproducible calculation period or execution time for the respective algorithm. As a configuration parameter for a symmetric algorithm, this may match the respective application requirement. By way of example, the time or execution time for calculating input blocks, including the times required for input and output and also the key handling within the trusted platform module, can be indicated as a number of clock cycles. The resultant response time, such as for an input block, is then dependent on the clock frequency, which can likewise be indicated as a specification of the trusted platform module.
[0061] Hardware implementations of hash algorithms also allow indication of the required execution time or of the maximum necessary execution time based on clock cycles. This applies because the time for hashing an input block is independent of the data content. Hence, the necessary execution time for hashing data increases only linearly with the number of input blocks. For typical volumes of data in an application environment of the trusted platform module, it is therefore possible to indicate the realtime response time. By way of example, a corresponding realtime-compatible trusted platform module can be used in Profinet environments, flash memories, firmwares, etc.
[0062] When implementing asymmetric algorithms, the necessary execution time may also be dependent on the input data, depending on the actual hardware implementation. In the case of asymmetric algorithms, such as RSA or ECDSA, it is possible to estimate a maximum number of clock cycles by analyzing the underlying algorithm and the execution paths therefor. This also requires the indication of a maximum time, i.e., a maximum execution time for the algorithm.
[0063] In the case of random number generators, it is possible to use a deterministic algorithm that can be analyzed in terms of the execution paths therefor. Hardware support by radioactive or physical noise waves is also conceivable.
[0064] Overall, the realtime-compatible tamper-proof hardware device in the form of a trusted platform module provides a simple way of using realtime-compatible trusted platform modules in open networks, which reduces or supersedes the otherwise necessary physical security measures of networked security-relevant devices. In particular, application in the automation environment, such as in the equipment of networked automation devices with appropriate realtime-compatible trusted platform modules, is possible.
[0065] Although the invention has been illustrated and described in more detail by means of the preferred exemplary embodiment, the invention is not restricted by the disclosed examples, and other variations can be derived therefrom by a person skilled in the art without departing from the scope of protection of the invention.
[0066] Thus, while there have been shown, described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements and/or method steps which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements and/or method steps shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.
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A method for producing a hardware device, in particular a trusted platform module for the execution of at least one cryptographic algorithm, the hardware device corresponding to a real-time class, i.e., it fulfils specifiable run-time requirements for real-time applications, wherein the method comprises preparing at least one cryptographic algorithm in the manner of a program code; determining a maximum/longest execution time (WCET) for the algorithm, producing a tamper-proof hardware module, which is configured to execute the algorithm, and assigning the hardware module to a real-time class depending on the maximum/longest execution time (WCET).
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CROSS-REFERENCE TO RELATED APPLICATIONS
The disclosure claims priority to U.S. Provisional Patent Application No. 61/510,834, filed Jul. 22, 2011, entitled “SYSTEMS, METHODS AND APPARATUS FOR RADIO UPLINK POWER CONTROL,” and assigned to the assignee hereof. The disclosure of this prior application is considered part of, and is incorporated by reference in, this disclosure.
BACKGROUND
Aspects of the present invention relate to wireless communication, and in particular, to systems, method and apparatus configured to enable radio link power control.
Wireless communication systems are widely deployed to provide various types of communication content such as voice, data, and so on. These systems may be multiple-access systems capable of supporting communication with multiple users by sharing the available system resources (e.g., bandwidth and transmit power). Examples of such multiple-access systems include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, 3GPP Long Term Evolution (LTE) systems, and orthogonal frequency division multiple access (OFDMA) systems.
Generally, a wireless multiple-access communication system can simultaneously support communication for multiple wireless terminals (e.g. cellphones, tablet computers and other electronic devices). Each wireless terminal communicates with one or more base stations via transmissions on one or more uplinks and downlinks. A downlink (or forward link) refers to the communication link from the base stations to the wireless terminal, and an uplink (or reverse link) refers to the communication link from the wireless terminal to the base station. These communication links may be established via a single-in-single-out (SISO), multiple-in-single-out (MISO), or a multiple-in-multiple-out (MIMO) system.
A MIMO system employs multiple transmit antennas and multiple receive antennas for data transmission. A MIMO channel formed by the transmit and receive antennas may be decomposed into independent channels, which are also referred to as spatial channels. Each of the independent channels corresponds to a dimension. The MIMO system can provide improved performance (e.g., higher throughput and/or greater reliability) if the additional dimensions created by the multiple transmit and receive antennas are utilized.
A MIMO system supports time division duplex (TDD) and frequency division duplex (FDD) systems. In a TDD system, the uplink and downlink transmissions are within the same frequency region so that the reciprocity principle allows the estimation of the downlink channel from the uplink channel. This enables the base station to extract transmit beamforming gain on the downlink when multiple antennas are available at the base station.
The primary purpose of the base station is to provide a connection between a wireless terminal or terminals and the core communications network. To that end, base stations handle the radio transmission and reception to and from wireless terminals.
To establish a call connection between a wireless terminal and a base station, a Radio Access Bearer (RAB) is needed. The RAB carries voice or other data between the wireless terminal and the core communication network. There are different types of RABs for different types of data, such as, for example, voice data, streaming data (e.g. streaming a video clip), interactive data (e.g. interacting with a website) and others. Simultaneous connections to the voice and data channels require multiple RABs and may be referred to as Multi-RAB or MRAB connections. In the early days of combined voice and data networks, e.g. 3G UMTS, simultaneous voice and data connections were not prevalent. However, newer wireless terminal devices (e.g. touch-screen cellular telephones) increasingly use voice and data connections simultaneously. Unfortunately, because wireless terminals usually have limited transmit power, MRAB calls may increase the rate of dropped calls or connections due to the limited transmission power being divided between too many channels simultaneously. Accordingly, there is a need to improve the allocation of transmission power during MRAB calls to improve connection quality for wireless terminals.
SUMMARY
Various implementations of systems, methods and apparatus within the scope of the appended claims each have several aspects, no single one of which is solely responsible for the desirable attributes described herein. Without limiting the scope of the appended claims, some prominent features are described herein. After considering this discussion, and particularly after reading the section entitled “Detailed Description” one will understand how the features of various implementations are used to manage power allocation to various channels in MRAB calls.
In one aspect, a method of wireless communication in a voice and data communication is provided. The method includes detecting, in a wireless terminal, a power limited mode based on a condition of the wireless terminal. The method further includes suspending, based on the detecting, transmission of at least a portion of information of at least one uplink channel at the wireless terminal. The transmission is suspended for a duration of the detected power limited mode.
In another aspect, an apparatus for wireless communication in a voice and data communication is provided. The apparatus includes a receiver configured to receive data from a base station. The apparatus further includes a transmitter configured to transmit data to a base station. The apparatus further includes a processor configured to detect a power limited mode based on a condition of a wireless terminal and suspend transmission of the uplink control data on a first channel. The processor is further configured to suspend, based on the detected power limited mode, transmission of at least a portion of information of at least one uplink channel at the wireless terminal. The processor is configured to suspend the transmission for a duration of the detected power limited mode.
In another aspect, another apparatus for wireless communication in a voice and data communication is provided. The apparatus includes means for detecting, in a wireless terminal, a power limited mode based on a condition of the wireless terminal. The apparatus further includes means for suspending, based on detection of the power limited mode, transmission of at least a portion of information of at least one uplink channel at the wireless terminal. The transmission is suspended for a duration of the detected power limited mode.
In another aspect, a computer program product for wirelessly communicating in a voice and data communication is provided. The computer program product includes a non-transitory computer readable medium includes instructions that when executed cause an apparatus to detect, in a wireless terminal, a power limited mode based on a condition of the wireless terminal. The medium further includes instructions that, when executed, cause the apparatus to suspend, based on the detected power limited mode, transmission of at least a portion of information of at least one uplink channel at the wireless terminal. The transmission is suspended for a duration of the detected power limited mode.
BRIEF DESCRIPTION OF THE DRAWINGS
So that the manner in which features of the present disclosure can be understood in detail, a more particular description, briefly summarized above, may be had by reference to aspects, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only certain aspects of this disclosure and are therefore not to be considered limiting of its scope, for the description may admit to other equally effective aspects.
FIG. 1 is a functional block diagram of a wireless communication system.
FIG. 2 is a functional block diagram of components that may be employed to facilitate communication between communication nodes, such a wireless terminal and a base station.
FIG. 3 is a flowchart illustrating an implementation of a method of wireless communication in the wireless terminal of FIG. 1 .
FIG. 4 is a flowchart illustrating an implementation of another method of wireless communication in the wireless terminal of FIG. 1 .
FIG. 5 is a flowchart illustrating an implementation of another method of wireless communication in the wireless terminal of FIG. 1 .
FIG. 6 is a block diagram of an example wireless terminal.
In accordance with common practice the various features illustrated in the drawings may not be drawn to scale. Accordingly, the dimensions of the various features may be arbitrarily expanded or reduced for clarity. In addition, some of the drawings may not depict all of the components of a given system, method or device. Finally, like reference numerals may be used to denote like features throughout the specification and figures.
DETAILED DESCRIPTION
Various aspects of embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein may be embodied in a wide variety of forms and that any specific structure and/or function described herein is merely illustrative. Based on the present disclosure one skilled in the art should appreciate that an aspect described herein may be implemented independently of any other aspects and that two or more of these aspects may be combined in various ways. For example, an apparatus may be implemented and/or a method may be practiced using any number of the aspects set forth herein. In addition, such an apparatus may be implemented and/or such a method may be practiced using other structure and/or functionality in addition to or other than one or more of the aspects set forth herein.
The techniques described herein may be used for various wireless communication networks such as Code Division Multiple Access (CDMA) networks, Time Division Multiple Access (TDMA) networks, Frequency Division Multiple Access (FDMA) networks, Orthogonal FDMA (OFDMA) networks, Single-Carrier FDMA (SC-FDMA) networks, etc. The terms “networks” and “systems” are often used interchangeably. A CDMA network may implement a radio technology such as Universal Terrestrial Radio Access (UTRA), cdma2000, etc. UTRA includes Wideband-CDMA (W-CDMA) and Low Chip Rate (LCR). cdma2000 covers IS-2000, IS-95 and IS-856 standards. A TDMA network may implement a radio technology such as Global System for Mobile Communications (GSM). An OFDMA network may implement a radio technology such as Evolved UTRA (E-UTRA), IEEE 802.11, IEEE 802.16, IEEE 802.20, IEEE 802.22, Flash-OFDMA, etc. UTRA, E-UTRA, and GSM are part of Universal Mobile Telecommunication System (UMTS). Long Term Evolution (LTE) is an upcoming release of UMTS that uses E-UTRA. UTRA, E-UTRA, GSM, UMTS and LTE are described in documents from an organization named “3rd Generation Partnership Project” (3GPP). Similarly, cdma2000 is described in documents from an organization named “3rd Generation Partnership Project 2” (3GPP2). These various radio technologies and standards are known in the art.
In some aspects the teachings herein may be employed in a network that includes macro scale coverage (e.g., a large area cellular network such as a 3G network, typically referred to as a macro cell network) and smaller scale coverage (e.g., a residence-based or building-based network environment). As a wireless terminal (WT) or user equipment (UE) moves through such a network, the wireless terminal may be served in certain locations by base stations (BSs) or access nodes (ANs) that provide macro coverage while the wireless terminal may be served at other locations by access nodes that provide smaller scale coverage, e.g. femto nodes (FNs). In some aspects, the smaller coverage nodes may be used to provide incremental capacity growth, in-building coverage, and different services (e.g., for a more robust user experience). In the discussion herein, a node that provides coverage over a relatively large area may be referred to as a macro node. A node that provides coverage over a relatively small area (e.g., a residence) may be referred to as a femto node. A node that provides coverage over an area that is smaller than a macro area and larger than a femto area may be referred to as a pico node (e.g., providing coverage within a commercial building).
A cell associated with a macro node, a femto node, or a pico node may be referred to as a macro cell, a femto cell, or a pico cell, respectively. In some implementations, each cell may be further associated with (e.g., divided into) one or more sectors.
In various applications, other terminology may be used to reference a macro node, a femto node, or a pico node. For example, a macro node may be configured or referred to as an access node, access point, base station, Node B, eNodeB, macro cell, and so on. Also, a femto node may be configured or referred to as a Home NodeB (HNB), Home eNodeB (HeNB), access point access point, femto cell, and so on.
FIG. 1 is a functional block diagram of a wireless communication system 10 . The wireless communication system 10 includes at least one wireless terminal 100 and at least one base station 101 communicating with each other over a first communication link 161 and a second communication link 163 . Each of the first and second communication links 161 , 163 can be a single-packet communication link on which a single packet may be transmitted during each cycle or a multi-packet communication link on which on which multiple packets may be transmitted during each cycle. For example, the first communication link 161 can be a dual-packet communication link on which zero, one, or two packets can be transmitted during each cycle.
The wireless terminal 100 includes a processor 110 in data communication with a memory 120 , an input device 130 , and an output device 140 . The processor is further in data communication with a modem 150 and a transceiver 160 . The transceiver 160 is also in data communication with the modem 150 and an antenna 170 . The wireless terminal 100 and components thereof are powered by a battery 180 and/or an external power source. In some embodiments, the battery 180 , or a portion thereof, is rechargeable by an external power source via a power interface 190 . Although described separately, it is to be appreciated that functional blocks described with respect to the wireless terminal 100 need not be separate structural elements. For example, the processor 110 and memory 120 may be embodied in a single chip. Similarly, two or more of the processor 110 , modem 150 , and transceiver 160 may be embodied in a single chip.
The processor 110 can be a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any suitable combination thereof designed to perform the functions described herein. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.
The processor 110 can be coupled, via one or more buses, to read information from or write information to the memory 120 . The processor may additionally, or in the alternative, contain memory, such as processor registers. The memory 120 can include processor cache, including a multi-level hierarchical cache in which different levels have different capacities and access speeds. The memory 120 can also include random access memory (RAM), other volatile storage devices, or non-volatile storage devices. The storage can include hard drives, optical discs, such as compact discs (CDs) or digital video discs (DVDs), flash memory, floppy discs, magnetic tape, and Zip drives.
The processor 110 is also coupled to an input device 130 and an output device 140 for, respectively, receiving input from and providing output to, a user of the wireless terminal 100 . Suitable input devices include, but are not limited to, a keyboard, buttons, keys, switches, a pointing device, a mouse, a joystick, a remote control, an infrared detector, a video camera (possibly coupled with video processing software to, e.g., detect hand gestures or facial gestures), a motion detector, or a microphone (possibly coupled to audio processing software to, e.g., detect voice commands). Suitable output devices include, but are not limited to, visual output devices, including displays and printers, audio output devices, including speakers, headphones, earphones, and alarms, and haptic output devices, including force-feedback game controllers and vibrating devices.
The processor 110 is further coupled to a modem 150 and a transceiver 160 . The modem 150 and transceiver 160 prepare data generated by the processor 110 for wireless transmission over the communication links 161 , 163 via the antenna 170 according to one or more air interface standards. The modem 150 and transceiver 160 also demodulate data received over the communication links 161 , 163 via the antenna 170 according to one or more air interface standards. The transceiver can include a transmitter 162 , a receiver 164 , or both. In other embodiments, the transmitter 162 and receiver 164 are two separate components. The modem 150 and transceiver 160 , can be embodied as a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any suitable combination thereof designed to perform the functions described herein. The antenna 170 can include multiple antennas for multiple-input/multiple-output (MIMO) communication.
The wireless terminal 100 and components thereof are powered by a battery 180 and/or an external power source. The battery 180 can be any device which stores energy, and particularly any device which stores chemical energy and provides it as electrical energy. The battery 180 can include one or more secondary cells including a lithium polymer battery, a lithium ion battery, a nickel-metal hydride battery, or a nickel cadmium battery, or one or more primary cells including an alkaline battery, a lithium battery, a silver oxide battery, or a zinc carbon battery. The external power source can include a wall socket, a vehicular cigar lighter receptacle, a wireless energy transfer platform, or the sun.
In some embodiments, the battery 180 , or a portion thereof, is rechargeable by an external power source via a power interface 190 . The power interface 190 can include a jack for connecting a battery charger, an inductor for near field wireless energy transfer, or a photovoltaic panel for converting solar energy into electrical energy.
In some embodiments, the wireless terminal 100 is a mobile telephone, a personal data assistant (PDAs), a hand-held computer, a laptop computer, a wireless data access card, a GPS receiver/navigator, a camera, an MP3 player, a camcorder, a game console, a wrist watch, a clock, or a television.
The base station 101 also includes at least a processor 111 coupled to a memory 112 and a transceiver 165 . The transceiver 165 includes a transmitter 167 and a receiver 166 coupled to an antenna 171 . The processor 111 , memory 112 , transceiver 165 , and antenna 171 can be embodied as described above with respect to the wireless terminal 100 .
In the wireless communication system 10 of FIG. 1 , the base station 101 can transmit data packets to the wireless terminal 100 via a first communication link 161 and a second communication link 163 . In one embodiment, the base station can transmit, via the first communication link 161 , up to two packets per cycle, whereas the base station 101 can only transmit up to one packet per cycle via the second communication link 163 .
FIG. 2 depicts several sample components that may be employed to facilitate communication between communication nodes, such as a wireless terminal and a base station. Specifically, FIG. 2 is a simplified block diagram of a first wireless device 210 (e.g., a base station) and a second wireless device 250 (e.g., a wireless terminal) of a MIMO system 200 . At the first device 210 , traffic data for a number of data streams is provided from a data source 212 to a transmit (TX) data processor 214 .
In some implementations, each data stream is transmitted over a respective transmit antenna. The TX data processor 214 formats, codes, and interleaves the traffic data for each data stream based on a particular coding scheme selected for that data stream.
The coded data for each data stream may be multiplexed with pilot data using OFDM techniques. The pilot data is typically a known data pattern that is processed in a known manner and may be used at the receiver system to estimate the channel response. The multiplexed pilot and coded data for each data stream is then modulated (i.e., symbol mapped) based on a particular modulation scheme (e.g., BPSK, QSPK, M-PSK, or M-QAM) selected for that data stream to provide modulation symbols. The data rate, coding, and modulation for each data stream may be determined by instructions performed by a processor 230 . A data memory 232 may store program code, data, and other information used by the processor 230 or other components of the device 210 .
The modulation symbols for all data streams are then provided to a TX MIMO processor 220 , which may further process the modulation symbols (e.g., for OFDM). The TX MIMO processor 220 then provides modulation symbol streams to transceivers (XCVR) 222 A through 222 T. In some aspects, the TX MIMO processor 220 applies beam-forming weights to the symbols of the data streams and to the antenna from which the symbol is being transmitted.
Each transceiver 222 receives and processes a respective symbol stream to provide one or more analog signals, and further conditions (e.g., amplifies, filters, and upconverts) the analog signals to provide a modulated signal suitable for transmission over the MIMO channel. Modulated signals from transceivers 222 A through 222 T are then transmitted from antennas 224 A through 224 T, respectively.
At the second device 250 , the transmitted modulated signals are received by antennas 252 A through 252 R and the received signal from each antenna 252 is provided to a respective transceiver (XCVR) 254 A through 254 R. Each transceiver 254 conditions (e.g., filters, amplifies, and downconverts) a respective received signal, digitizes the conditioned signal to provide samples, and further processes the samples to provide a corresponding “received” symbol stream.
A receive (RX) data processor 165 then receives and processes the received symbol streams from transceivers 254 based on a particular receiver processing technique to provide “detected” symbol streams. The RX data processor 165 then demodulates, deinterleaves, and decodes each detected symbol stream to recover the traffic data for the data stream. The processing by the RX data processor 165 is complementary to that performed by the TX MIMO processor 220 and the TX data processor 214 at the device 210 .
The processor 270 formulates an uplink message, which may comprise various types of information regarding the communication link and/or the received data stream. The reverse link message is then processed by a TX data processor 238 , which also receives traffic data for a number of data streams from a data source 236 , modulated by a modulator 280 , conditioned by the transceivers 254 A through 254 R, and transmitted back to the device 210 .
At the device 210 , the modulated signals from the second device 250 are received by the antennas 224 , conditioned by the transceivers 222 , demodulated by a demodulator (DEMOD) 240 , and processed by an RX data processor 242 to extract the uplink message transmitted by the second device 250 . The processor 230 then processes the extracted message.
FIG. 2 also illustrates that the communication components may include one or more components that perform access control. For example, an access control component 290 may cooperate with the processor 230 and/or other components of the device 210 to send/receive signals to/from another device (e.g., device 250 ). Similarly, an access control component 292 may cooperate with the processor 270 and/or other components of the device 250 to send/receive signals to/from another device (e.g., device 210 ). It should be appreciated that for each device 210 and 250 the functionality of two or more of the described components may be provided by a single component. For example, a single processing component may provide the functionality of the access control component 290 and the processor 230 and a single processing component may provide the functionality of the access control component 292 and the processor 270 .
The interface between base stations and wireless terminals may be described by a protocol stack that consists of a number of protocol layers, each giving a specific service to the next layer above and/or below. For example, a top layer of the protocol stack, sometimes referred to as the radio resource control (RRC) layer, may control signaling to control the wireless connection to the wireless terminal. This layer may additionally provide control of aspects of the wireless terminal from the base station and may include functions to control radio bearers, physical channels, mapping of different channel types, measurement and other functions.
The next layer down, sometimes referred to as the medium access control (MAC) layer, offers logical channels to the layers above. The logical channels are distinguished by the different type of information they carry, and may include the Dedicated Control Channel (DCCH), Common Control Channel (CCCH), Dedicated Traffic Channel (DTCH), Common Traffic Channel (CTCH), Broadcast Control Channel (BCCH), the Paging Control Channel (PCCH) and others. The MAC layer may perform scheduling and mapping of logical channel data onto the transport channels provided by the physical layer. Also, for common transport channels, the MAC layer may add addressing information to distinguish data flows intended for different wireless terminals.
Finally, a lowest level, sometimes referred to as the physical layer, may control the transmission and reception of data over the radio frequency spectrum and may offer transport channels to the MAC layer. The transmission functions of the physical layer may include channel coding and interleaving, multiplexing of transport channels, mapping to physical channels, spreading, modulation and power amplification, with corresponding functions for reception.
Transport channels may be common i.e. shared by multiple wireless terminals at once, or dedicated to a single wireless terminal during a time period. Different types of transport channels have different characteristics of the transmission (e.g. FACH, RACH, DSCH, BCH, PCH, and others). Dedicated transport channels are assigned to only one handset at a time.
Each channel that a wireless terminal uses to communicate with a base station requires transmission power, and by the nature of many wireless terminal devices, the total transmission capability is limited. Thus, a major cause contributing to higher dropped connection rates for MRAB connections (e.g. simultaneous voice and data connections) vs. single RAB connections (e.g. voice only connection) is the faster exhaustion of the wireless terminal transmit power on the uplink connection. The reason for this is that in MRAB connections require additional uplink channels that the wireless terminal must transmit to maintain the connection. For example, in certain cellular telephone networks, the High Speed Dedicated Physical Control Channel (HS-DPCCH) may carry the following types of control information from the wireless terminal to the base station: (1) Channel Quality Indicator (CQI), which is a number between 0 and 30; acknowledgments (ACK); and Negative Acknowledgments (NACK) for downlink transmission on High Speed Physical Downlink Shared Channel (HS-DPSCH). A wireless terminal needs a part of its available transmission power to HS-DPCCH. For example, a typical amount of power allocated to HS-DPCCH may range between 3 dB and 5 dB. This transmission power is taken away from the power that could have been assigned to uplink signaling radio bearer (SRB) and/or uplink voice radio bearer and/or uplink data radio bearer transmission capacity. This reduction in transmission capacity of uplink channels results in higher rates of dropped calls for cellular telephones while making MRAB calls. For example, a cellular phone use may be making a voice call while accessing a website (i.e. a MRAB call) and that user's transmission capacity of the voice channel is reduced by the need to allocate power to the HS-DPCCH.
When a wireless terminal is running out of transmission power during a MRAB connection, the primary concern is to keep the signaling radio bearer and voice radio bearers in good standing. Downlink data throughput on HS-DPSCH is of lower priority. Thus, one method to reduce dropped connections at the wireless terminal suspends sending of control information on the HS-DPCCH for MRAB calls when wireless terminal is in the limited transmission power condition. Given this broader concept, there are at multiple methods of suspending sending of control data on the HS-DPCCH. For example, control data can be completely suspended i.e. suspension of ACK, NACK and CQI on the HS-DPCCH. Alternatively, control data may be selectively suspended, such as suspending only CQI while ACK and NACK data are still sent on the HS-DPCCH.
FIG. 3 is a flowchart illustrating an implementation of a method 300 of wireless communication in the wireless terminal 100 of FIG. 1 . Although the method 300 is described herein with reference to the wireless terminal 100 discussed above with respect to FIG. 1 , a person having ordinary skill in the art will appreciate that the method 300 may be implemented by any other suitable device. In an embodiment, method 300 may be performed by the CPU 110 in conjunction with the transmitter 162 , the receiver 164 , and the memory 120 . Although the method 300 is described herein with reference to a particular order, in various embodiments, blocks herein may be performed in a different order, or omitted, and additional blocks may be added.
The method 300 begins at decision block 310 where the wireless terminal 100 determines whether a power limited mode is enabled. A power limited mode may be enabled by a variety of conditions at the wireless terminal 100 . For example, a power limited mode may be enabled as the wireless terminal 100 crosses a set threshold of transmit power. That is, a wireless terminal 100 capable of transmitting at a maximum power of, for example, 23 dB may enter a power limited mode once the current transmission power exceeds a threshold such as, for example, 20 dB. The power limited mode may trigger a variety of changes to the operating parameters of the wireless terminal 100 , such as those described below. Alternatively, the power limited mode may be entered when the wireless terminal 100 selects one of the Transport Format Combinations from the minimum set of Transmit Format Combinations, as described in the 3GPP technical specifications, such as 25.321 and 25.133. Other implementations may have additional logic for enabling a power saving mode.
If, at decision block 310 , the wireless terminal 100 determines that it is not in a power limited mode, then the method returns to decision block 310 and restarts. If, however, at decision block 310 the wireless terminal 100 determines it is in a power limited mode, then the method moves to block 320 .
At block 320 , the wireless terminal 100 sends a low channel quality index to the base station on the HS-DPCCH. The base station schedules downlink transmission on the HS-DPSCH based on the CQI sent by the wireless terminal 100 on the HS-DPCCH. The process then moves to block 330 .
At block 330 , the wireless terminal 100 suspends HS-DPCCH reporting data to the base station. In one embodiment, the wireless terminal 100 may completely suspend HS-DPCCH reporting data i.e. suspend ACK, NACK and CQI reporting data. In an alternative embodiment, the wireless terminal 100 may only suspend the CQI reporting data. Notably, in both embodiments, the CQI reporting data is suspended.
When the CQI transmission is suspended, the base station may assume that the CQI was sent by the wireless terminal 100 but was not received and/or decoded properly by the base station. Accordingly, the base station may continue to schedule downlink transmission to the wireless terminal 100 on the HS-DPSCH. The base station may continue to use the last reported value of CQI for scheduling downlink transmissions. Because of this, the wireless terminal 100 needs to make sure that the last CQI sent before suspending CQI transmission is not low (as is accomplished at block 320 ). The method then moves to block 340 .
At block 340 , the wireless terminal 100 assigns the HS-DPCCH transmission power (i.e. the power previously allocated to transmitting the HS-DPCCH reporting data) to an alternate channel, such as a voice or data channel. In doing so, the wireless terminal 100 may increase the reliability of those alternate channels by increasing their transmission power level. The method then moves to decision block 350
If at decision block 350 the wireless terminal 100 determines that the power limited mode is not disabled (i.e. enabled), then the method returns to decision block 350 . If, however, at decision block 350 the wireless terminal 100 determines that the power limited mode is disabled, then it moves to block 360 .
At block 360 the wireless terminal 100 resumes transmission of HS-DPCCH reporting data (e.g. CQI data). The process then returns to decision block 310 and restarts.
FIG. 4 is a flowchart illustrating another implementation of a method 400 of transmission power control in the wireless terminal 100 of FIG. 1 . Although the method 400 is described herein with reference to the wireless terminal 100 discussed above with respect to FIG. 1 , a person having ordinary skill in the art will appreciate that the method 400 may be implemented by any other suitable device. In an embodiment, method 400 may be performed by the CPU 110 in conjunction with the transmitter 162 , the receiver 164 , and the memory 120 . Although the method 400 is described herein with reference to a particular order, in various embodiments, blocks herein may be performed in a different order, or omitted, and additional blocks may be added.
The method 400 begins at decision block 410 where the wireless terminal 100 determines whether it is in a power limited mode.
If, at decision block 410 , the wireless terminal 100 determines that it is not in a power limited mode, then the method returns to decision block 410 and restarts. If, however, at decision block 410 , the wireless terminal 100 determines it is in a power limited mode, then the method moves to block 420 .
At block 420 , the wireless terminal 100 sends a predetermined sequence of CQI reports to the base station on the HS-DPCCH. For example, a CQI sequence of 0,30,0,30,0 may indicate that CQI suspension will follow. The base station recognizes this CQI sequence and stops scheduling downlink transmission on the HS-DPSCH. The process then moves to block 430 .
At block 430 , the wireless terminal 100 suspends CQI reporting to the base station. Alternatively, entire HS-DPCCH transmission is suspended. The method then moves to block 440 .
At block 440 , the wireless terminal 100 re-assigns the transmission power preciously assigned to HS-DPCCH to alternate transmission channels, such as, for example, the DPDCH and DPCCH channels. The method then moves to decision block 450 .
If, at decision block 450 , the wireless terminal 100 determines that the power limited mode is not disabled (i.e. enabled), then the method returns to decision block 450 . If, however, at decision block 450 the wireless terminal 100 determines that the power limited mode is disabled, then it moves to block 460 .
At block 460 the wireless terminal 100 resumes CQI reporting on the HS-DPCCH. Alternatively, entire HS-DPCCH transmission is resumed. The process then returns to decision block 410 and restarts.
FIG. 5 is a flowchart illustrating an implementation of another method 500 of wireless communication in the wireless terminal 100 of FIG. 1 . Although the method 500 is described herein with reference to the wireless terminal 100 discussed above with respect to FIG. 1 , a person having ordinary skill in the art will appreciate that the method 500 may be implemented by any other suitable device. In an embodiment, method 500 may be performed by the CPU 110 in conjunction with the transmitter 162 , the receiver 164 , and the memory 120 . Although the method 500 is described herein with reference to a particular order, in various embodiments, blocks herein may be performed in a different order, or omitted, and additional blocks may be added.
The method starts at block 510 where the wireless terminal 100 detects the power limited mode based on a condition of the wireless terminal. The power limited mode may be enabled based on operating parameters of the wireless terminal 100 such as those described above with respect to FIG. 3 .
The method then moves to block 520 where the wireless terminal 100 suspends transmission of transmission of at least a portion of information of at least one uplink channel at the wireless terminal 100 . For example, the wireless terminal 100 can suspend uplink control information for HS-DPSCH, such as CQI reporting data, or all HS-DPCCH data. In an embodiment, the wireless terminal 100 can independently suspend portions of the uplink channel such as, for example, CQI, ACKs, and NACKs. The wireless terminal 100 can suspend transmission, based on the detected power limited mode, for a duration of the power limited mode.
In the illustrated embodiment, the method then moves to block 530 where the wireless terminal 100 reassigns the power previously assigned to the uplink data transmission to another data transmission channel, such as a voice channel or data channel. For example, a wireless terminal 100 may reassign to the Dedicated Physical Data Channel (DPDCH) and Dedicated Physical Control Channel (DPCCH) the power previously assigned to HS-DPCCH. The reassignment of power may increase the reliability of the alternate channels and reduce dropped connection rates. For example, a user of a cellular telephone may experience less dropped calls while using data and voice channels simultaneously if the method 500 is implemented by the user's cellular telephone. In another embodiment, block 530 may be omitted.
FIG. 6 is a block diagram of an example wireless terminal 600 in accordance with certain aspects of the present disclosure. Those skilled in the art will appreciate that a wireless terminal may have more or fewer components than the simplified wireless terminal 600 illustrated in FIG. 6 . The wireless terminal 600 illustrates only those components useful for describing some prominent features of implementations within the scope of the claims.
The wireless terminal 600 includes a control circuit 610 , a detecting circuit 620 , a transmitting circuit 630 , a receiving circuit 640 and an antenna 650 . In one implementation the control circuit 610 is configured to perform one or more blocks as described in FIGS. 3-5 above. For example, the control circuit 610 can be configured to suspend transmission of uplink data on a first channel, such as the HS-DPCCH. In one implementation, the control circuit 610 includes means for suspending transmission of uplink data on a first channel includes a control circuit.
In one implementation the detecting circuit 620 is configured to detect a power limited mode based on a condition of the wireless terminal 600 . In one implementation, the detecting circuit 620 can include means for detecting. In one implementation, the transmitting circuit 630 is configured to transmit data to a base station via the antenna 650 . In one implementation, the transmitting circuit 630 can include means for transmitting. In one implementation, the receiving circuit 640 is configured to receive data from a base station via the antenna 650 . In one implementation, the receiving circuit 640 can include means for receiving.
A wireless terminal may comprise, be implemented as, or known as user equipment, a subscriber station, a subscriber unit, a mobile station, a mobile phone, a mobile node, a remote station, a remote terminal, a user terminal, a user agent, a user device, or some other terminology. In some implementations a wireless terminal may comprise a cellular telephone, a cordless telephone, a session initiation protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA), a handheld device having wireless connection capability, or some other suitable processing device connected to a wireless modem. Accordingly, one or more aspects taught herein may be incorporated into a phone (e.g., a cellular phone or smart phone), a computer (e.g., a laptop), a portable communication device, a portable computing device (e.g., a personal data assistant), an entertainment device (e.g., a music device, a video device, or a satellite radio), a global positioning system device, or any other suitable device that is configured to communicate via a wireless medium.
A base station may comprise, be implemented as, or known as a NodeB, an eNodeB, a radio network controller (RNC), a base station (BS), a radio base station (RBS), a base station controller (BSC), a base transceiver station (BTS), a transceiver function (TF), a radio transceiver, a radio router, a basic service set (BSS), an extended service set (ESS), or some other similar terminology.
In some aspects a base station may comprise an access node for a communication system. Such an access node may provide, for example, connectivity for or to a network (e.g., a wide area network such as the Internet or a cellular network) via a wired or wireless communication link to the network. Accordingly, a base station may enable another node (e.g., a wireless terminal) to access a network or some other functionality. In addition, it should be appreciated that one or both of the nodes may be portable or, in some cases, relatively non-portable.
Also, it should be appreciated that a wireless node may be capable of transmitting and/or receiving information in a non-wireless manner (e.g., via a wired connection). Thus, a receiver and a transmitter as discussed herein may include appropriate communication interface components (e.g., electrical or optical interface components) to communicate via a non-wireless medium.
A wireless terminal or node may communicate via one or more wireless communication links that are based on or otherwise support any suitable wireless communication technology. For example, in some aspects a wireless terminal may associate with a network. In some aspects the network may comprise a local area network or a wide area network. A wireless terminal may support or otherwise use one or more of a variety of wireless communication technologies, protocols, or standards such as those discussed herein (e.g., CDMA, TDMA, OFDM, OFDMA, WiMAX, Wi-Fi, and so on). Similarly, a wireless terminal may support or otherwise use one or more of a variety of corresponding modulation or multiplexing schemes. A wireless terminal may thus include appropriate components (e.g., air interfaces) to establish and communicate via one or more wireless communication links using the above or other wireless communication technologies. For example, a wireless terminal may comprise a wireless transceiver with associated transmitter and receiver components that may include various components (e.g., signal generators and signal processors) that facilitate communication over a wireless medium.
It should be understood that any reference to an element herein using a designation such as “first,” “second,” and so forth does not generally limit the quantity or order of those elements. Rather, these designations may be used herein as a convenient method of distinguishing between two or more elements or instances of an element. Thus, a reference to first and second elements does not mean that only two elements may be employed there or that the first element must precede the second element in some manner. Also, unless stated otherwise a set of elements may comprise one or more elements.
Those of skill in the art would understand that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.
Those of skill would further appreciate that any of the various illustrative logical blocks, modules, processors, means, circuits, and algorithm steps described in connection with the aspects disclosed herein may be implemented as electronic hardware (e.g., a digital implementation, an analog implementation, or a combination of the two, which may be designed using source coding or some other technique), various forms of program or design code incorporating instructions (which may be referred to herein, for convenience, as “software” or a “software module), or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present disclosure.
The various illustrative logical blocks, modules, and circuits described in connection with the aspects disclosed herein may be implemented within or performed by an integrated circuit (IC), a wireless terminal, or a base station. The IC may comprise a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, electrical components, optical components, mechanical components, or any combination thereof designed to perform the functions described herein, and may execute codes or instructions that reside within the IC, outside of the IC, or both. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.
It is understood that any specific order or hierarchy of steps in any disclosed process is an example of a sample approach. Based upon design preferences, it is understood that the specific order or hierarchy of steps in the processes may be rearranged while remaining within the scope of the present disclosure. The accompanying method claims present elements of the various steps in a sample order, and are not meant to be limited to the specific order or hierarchy presented.
The functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A storage media may be any available media that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer. Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. Disk and disc, as used herein, includes compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media. In summary, it should be appreciated that a computer-readable medium may be implemented in any suitable computer-program product.
The above description is provided to enable any person skilled in the art to make or use embodiments within the scope of the appended claims. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects without departing from the scope of the disclosure. Thus, the present disclosure is not intended to be limited to the aspects shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
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In some implementations of the present invention, improvement of connection quality and reduction of dropped connection rate are achieved by suspending the transmission of High Speed Dedicated Physical Control Channel (HS-DPCCH) data when a wireless terminal detects a power limiting mode during multi-radio access bearer (MRAB) connections and voice RAB is present, and correspondingly increasing uplink transmission power to voice and signaling data channels. In some implementations, the suspension of HS-DPCCH data can be complete or partial. When fully suspended, no data is sent on the HS-DPCCH. When partially suspended, no channel quality indicator (CQI) is transmitted. In both partial and full suspension schemes, the CQI transmission is suspended until the terminal detects that entry conditions to this state has been terminated.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a 35 USC 371 application of PCT/DE 01/01019 filed on Mar. 16, 2001.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention is directed to an improved device for pressure regulation of the type in which a closing body is prestressed against a valve seat by a helical spring.
2. Description of the Prior Art
In devices of the type with which this invention is concerned, an axially movable closing body is prestressed against an associated valve seat by means of a helical spring disposed coaxially to the closing body.
In devices of this generic type, an axially movable closing body is prestressed against the associated valve seat by means of a helical spring disposed coaxially to the closing body. Because of the instability of helical springs in the transverse direction, a compensation means is necessary to compensate for a resultant skewed spring position, since otherwise an uncontrolled lateral tilting behavior of the adjacently disposed closing body would occur, which would lead to an undefined response performance of the device.
From British Patent Disclosure GB 14 63 217, one such device is already known. In it, a compensation means is disposed axially between the closing body and the associated valve seat, in order to compensate for a skewed position of the helical spring and a resultant tendency to transverse tilting of the closing body. However, what is unsatisfactory in this prior art is that a positive-engagement contact between the compensation means and the closing body is necessary, which requires precision-fitted and therefore expensive production. Since furthermore the compensation means is in permanent engagement with the valve seat associated with the closing body, the flow resistance at the valve seat is undesirably increased in the open position of the closing body.
SUMMARY OF THE INVENTION
The device of the invention has the advantage over the prior art that because of the bracing, provided in the radial direction, of the compensation means on the inner wall of the housing, the radial force components generated by the helical spring under initial tension, are absorbed and compensated for, so that only the components generated in the axial direction by the helical spring are carried onward by the compensation means. Because of the disposition of the compensation means between the helical spring and the closing body, the flow resistance at the valve seat furthermore remains essentially unaffected.
BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing features and advantages of the invention will become apparent from the detailed description contained below, taken with the drawings, in which;
FIG. 1 shows a view in longitudinal section of a device according to the invention, which includes a housing with a closing body received in it; a helical spring with a compensation element is disposed between the closing body and one part of the housing;
FIG. 2 shows the device of FIG. 1 in a plan view;
FIG. 3 is a plan view showing the compensation element employed in the device;
FIG. 4 shows a cross section through the compensation element of FIG. 3;
FIG. 5 is a longitudinal section of a second embodiment of the device of the invention; dashed lines for the closing body and the compensation element represent a closed valve function, while the solid lines represent an opened valve function, in which the closing body is axially deflected out of its valve seat;
FIG. 6 is a longitudinal section of the compensation for an incident skewed spring position of the helical spring by bending of the compensation element; and
FIG. 7 is a longitudinal section of the compensation for an even greater skewed spring position by corresponding bending of the compensation element.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The device indicated in its entirety by reference numeral 10 in FIG. 1 has a housing 11 , in which a closing body 12 is received that is supported on a lower, narrowed-diameter region 11 ′ of the housing 11 embodied as a valve seat and is axially movable along the longitudinal axis 11 ″ of the housing 11 . In the axial direction, a helical spring 14 is disposed between the closing body 12 and a housing part 13 , embodied as a closure cap in the upper region of the housing 11 ; the upper end of the helical spring is seated within a central bulge in the closure cap 13 , and its opposite lower end is supported on a compensation element 15 , which with its central region 15 ′ acts upon the closing body 12 . To that end, the central region 15 ′ of the compensation element 15 is pre-curved in dome-shaped fashion in the direction of the adjacent closing body 12 ; that is, the central region 15 ′ has the approximate shape of a segment of a spherical shell, whose concave side faces toward the helical spring 14 ; spring arms 15 ″ of the compensation element 12 that protrude radially from the central region 15 ′ are braced resiliently with their ends on the inner wall of the housing 11 , so that as a result, the compensation element 15 is under transverse initial tension. A radially encompassing annular transitional portion 15 ′″ between the dome-shaped region 15 ′ of the compensation element 15 and the spring arms 15 ″ that protrude radially from the latter serves as what in the installed position is a plane bearing face for the associated end of the helical spring 14 ; the diameter of the annular transitional portion 15 ′″ is adapted to the diameter of the helical spring 14 . The compensation element 15 is in frictional-engagement contact, for instance, with the closing body 12 , since the apex as an extreme point of the dome-shaped region 15 ′ acts upon the bearing face 12 ′, facing toward it, of the closing body 12 , specifically approximately centrally in the longitudinal axis 11 ″ of the housing 11 . The closing body 12 is embodied cylindrically in its lower region 16 , and this region 16 is guided in a receiving bore 17 of the housing 11 that has a diameter corresponding to it. While the housing 11 is widened in diameter in stages upward in the axial direction from its bottom region 17 , the cylindrical region 16 of the closing body 12 is adjoined at the top by a sealing portion 19 in the form of a spherical segment associated with the valve seat 11 ′, and this portion ends at a radially outward-protruding collar 20 . Extending between the bottom region 17 of the housing 11 and the portion of the housing 11 that is embodied as the valve seat 11 ′ is a transitional portion, which has a larger diameter than the associated cylindrical region 16 of the closing body 12 and that has inlet openings 21 disposed transversely to the longitudinal axis 11 ″ of the housing 11 ; a hollow chamber approximately in the form of an annular gap extends between the wall of the transitional portion and the adjacent cylindrical region 16 of the closing body 12 . Outlet openings 22 are provided in the housing part 13 that closes off the housing 11 at the top. Since the closing body 12 with its spherical-layered sealing portion 19 is seated on the associated valve seat 11 ′, the device 10 is in the closed valve function position in FIG. 1 .
FIG. 2 on the one hand shows the location of the closure cap 13 and on the other the geometric disposition of the spring arms 15 ″, belonging to the compensation element 15 , inside the housing 11 of the device 10 . To that end, the closure cap 13 is inserted into the upper region of the housing 11 , and a radially encompassing, upward-protruding rim rests on the associated inner wall of the housing 11 . The closure cap 13 has, coaxially to the longitudinal axis 11 ″ of the housing 11 , a central outlet opening 22 and three recesses, spaced apart from one another in the circumferential direction, as outlet openings 22 , with spokelike struts located between them. For this purpose, the compensation element 15 likewise braced on the inner wall of the housing 11 has the spring arms 15 ″, which are spaced apart uniformly in the circumferential direction.
As FIG. 3 shows, the spring arms 15 ″ protruding radially from the dome-shaped region 15 ′ of the compensation element 15 for bracing purposes on the inner wall of the housing 11 are spaced apart uniformly in the circumferential direction; in the exemplary embodiment, this creates six spring arms, and thus the compensation element 15 has a sextuple symmetry. Also in the exemplary embodiment, the compensation element 15 is shaped from a leaflike steel sheet. From FIG. 4 it can be seen that the dome-shaped region 15 ′ has a substantially spherical curvature, thus resulting in a spherical shell segment. The dome-shaped region 15 ′ is bounded by the annular transitional portion 15 ′″, and between the circumference thereof and the respectively pivotably connected spring arm 15 ″, there is in each case a short, stepped shoulder 15 ″″, extending upward, obliquely to the axial direction, and disposed radially; the shoulder serves as a lateral stop for the movable end of the helical spring 14 . The spring arms 15 ″ thus pivotably connected to the central region 15 ′ via the transitional portion 15 ′″ and the respective shoulder 15 ″″ protrude radially outward approximately perpendicular to the respectively associated shoulder 15 ″″ and are arranged approximately in the shape of a star; in a variant embodiment, their ends are angled upward somewhat. In the non-installed state of the compensation element 15 , the spring arms 15 ″ are embodied as straight.
FIG. 5 shows the mode of operation of the device 10 of the invention in terms of a second embodiment, which differs from the first embodiment of FIGS. 1-4 in that the inner wall of the housing 11 , at the level of the spring arms 15 ″ of the compensation element 15 that engage it there, has a radially inward-protruding encompassing stop collar 24 , on which the spring arms 15 ″ come to rest. If the pressure introduced via the inlet openings 21 exceeds the counterpressure exerted on the closing body 12 by the helical spring 14 , then the closing body 12 is deflected axially upward with simultaneous compression of the helical spring 14 , and a flow conduit extends upward from the inlet openings 21 , through the annular-gaplike hollow chamber and past the spherical sealing portion 19 with the adjoining collar 20 to reach the outlet openings 22 provided in the closure cap 13 . This open valve function of the device 10 is shown by the solid lines for the axially displaceable closing body 12 and the compensation element 15 in FIG. 5, while by comparison the broken lines show the closed valve function. As FIG. 5 also shows, in the open valve function the axial deflection of the closing body 12 , via the frictionally engaged connection with the dome-shaped region 15 ′ of the compensation means 15 , leads to a slight isotropic bending of the spring arms 15 ″ braced on the inner wall of the housing.
FIG. 6 illustrates the mode of operation of the compensation means 15 in the event of a skewed position of the helical spring 14 . As the respective dashed and solid lines for the closing body 12 and the compensation element 15 in FIG. 6 show, this skewed position exists both in the closed and open position of the device 10 . As a result, the movable end, toward the closing body 12 , of the helical spring 14 exerts not only an axial force but also a force component in the radical direction. Since the movable end of the helical spring 14 acts upon the annular region 15 ′″ of the compensation element 15 , this skewed position causes torque bias of the dome-shaped region 15 ′, and the transverse and radial force component is absorbed by the laterally protruding spring arms 15 ″ braced on the inner wall of the housing 11 ; as a result, the spring arms 15 ″ oriented in the direction of the transverse torque bias become bent to a greater extent than the other spring arms 15 ″. The skewed state of the movable end of the helical spring 14 is thus compensated for by way of the dome-shaped region 15 ′ of the compensation element 15 . The radius of curvature of the dome-shaped region 15 ′ is selected such that the pivot point is located in the plane of the spring arms 15 ″, and a relative motion of the engagement point, located at the apex of the dome-shaped region 15 ′, between the compensation element 15 and the adjacent closing body 12 is thus maximally precluded, so that the contact point, defined by the apex of the dome-shaped region 15 ′, between the compensation element 15 and the adjacent bearing face 12 ′ of the closing body 12 is centered in the longitudinal axis 11 ″. The compressive force of the helical spring 14 is thus carried on axially, that is, without radial offset, to the closing body 12 . The compensation element 15 thus acts as a transverse force securing means, so that the closing body 12 is acted upon only in the axial direction and only centrally in the longitudinal axis 11 ″, independently of radial transverse forces.
FIG. 7 illustrates the mode of operation of the compensation element 15 in the event of an even more-pronounced skewed position of the helical spring 14 in the open position of the device 10 . While in the closed position, as the dashed lines show, the helical spring 14 acts upon the compensation element 15 concentrically to the longitudinal axis 11 ″, that is, without a skewed state, and the spring arms braced radially on the inner wall of the housing 11 are oriented isotropically, in the open position as shown by the solid lines, an eccentric displacement of the movable end of the helical spring 14 occurs relative to the longitudinal axis 11 ″. This in turn leads to a corresponding torque bias of the dome-shaped region 15 ′, and the spring arms 15 ″ oriented in the direction of the torque bias bend in accordance with the amount of torque bias, while the spring arms 15 ″ that are oriented away from the direction of the torque bias are virtually unaffected, thus resulting in an anisotropic response behavior of the spring arms 15 ″. Because of the embodiment of the compensation element 15 , a greater skewed spring position can thus be compensated for, so that with the device 10 of the invention, even helical springs with a major skewed position can be used.
The foregoing relates to preferred exemplary embodiments of the invention, it being understood that other variants and embodiments thereof are possible within the spirit and scope of the invention, the latter being defined by the appended claims.
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The invention relates to a device ( 10 ) for pressure regulation, having a housing ( 11 ) and a closing body ( 12 ) received axially movably therein, wherein the housing ( 11 ) has at least one pressure medium inlet ( 21 ) and one pressure medium outlet ( 22 ), and the closing body ( 12 ) is prestressed by a helical spring ( 14 ) against a valve seat ( 11′ ) in the housing, and at least one compensation means for the helical spring ( 14 ) is provided. The invention provides that as the compensation means, a compensation element ( 15 ) disposed between the closing body ( 12 ) and an end, oriented toward the closing body ( 12 ), of the helical spring ( 14 ) is provided, which is braced resiliently in the radial direction on the inner wall of the housing ( 11 ) and, with its central region ( 15 ′), is in preferably frictional-engagement contact with the closing body ( 12 ). The central region ( 15′ ) of the compensation element ( 15 ) is embodied as dome-shaped, and radially protruding spring arms ( 15 ″) are disposed peripherally to the central region ( 15′ ) of the compensation element ( 15 ).
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to medical devices that transmit laser energy. Specifically, the present invention relates to fiber optic laser energy delivery devices that emit a laser beam substantially laterally relative to the longitudinal axis of the fiber optic in a liquid medium.
2. Description of the Prior Art
In conventional laser energy delivery devices, a laser beam is emitted from the distal end of one or more optical fibers toward the point of application in the human body. Medical applications of lasers, such as in urology, gynecology, general surgery, orthopedics, ophthalmology and other surgical procedures, sometimes require laser energy to be emitted laterally from the axis of the optical fiber, so that, in urological applications for example, the lateral lobes of the prostate may undergo ablation and/or coagulation to create an enlarged region or passage for an enhanced fluid flow.
A prism can be used to laterally reflect light energy, so long as the index of refraction of the medium surrounding the reflective surface of the prism is substantially lower than the index of refraction of the prism itself, provided the reflective surface of the prism is at or below the critical angle for total internal reflection. This critical angle depends on the ratio of the respective refractive indices between the material of the prism and that of the environment or adjoining substance immediately outside the prism's reflective surface (i.e., the boundary interface). In order to achieve total internal reflection, for a given lateral reflection angle, a substance such as air (with a refractive index of about 1) can be used to assure a sufficiently low refractive index relative to that of a glass prism (refractive index 1.46). As a result, glass prisms function properly in an air environment. However, in water (refractive index 1.33) or in saline (refractive index about 1.33, depending on concentration), glass prisms do not effectively reflect light energy laterally substantially close to 90 degrees because the difference in refractive indices between the glass and the ambient medium is not great enough.
Moreover, surrounding the prism with air has disadvantages. One such disadvantage is that an enclosure transparent to the wavelength of energy being used, such as a glass encapsulating sleeve, is needed to contain and maintain an air environment at the prism interface. This, in turn, requires that the prism be positioned in precise orientation within the sleeve. To achieve this, a very tedious alignment procedure, difficult to accurately replicate in production, is involved. On the other hand, if the prism is not in precise alignment, internal reflection may not be achieved, or a laser beam in an errant direction may be emitted. Affixation of the glass encapsulating sleeve to the buffer coating or cladding of an optical fiber in an airtight manner is also difficult to assure in production.
Another problem with a glass sleeve is that an output power loss of five to ten percent may be experienced due to scattering and back reflection from the sleeve. This is a significant and undesirable power loss.
In surgical devices that come in contact with tissue it is also difficult to maintain the glass encapsulating sleeve at a sufficiently low temperature to prevent tissue from sticking thereto. If this happens, the temperature of the sleeve can quickly rise to the point of destruction, with the potential for leaving fragments of the glass sleeve in the body, which might necessitate surgery to remove them.
Still another problem with the glass encapsulating sleeve is that it is fragile. Physical stresses exerted during insertion through endoscopes or guiding catheters, or during the lasing procedure could cause the sleeve to break, leaving glass fragments at the medical procedure site and causing complications to the patient that might require an invasive surgical procedure to correct.
While laser energy may be laterally reflected from a polished metal surface in a fluid medium, some of the laser energy may be absorbed by the metal surface, thereby raising its temperature. If the metal surface is contaminated by tissue or body oils, the temperature of the metal surface can rapidly increase, causing the metal to deteriorate or melt.
Therefore, it would be desirable to have a medical device that reflects the laser energy laterally in a fluid medium without the need for a metal reflecting surface or glass encapsulating sleeve. The present invention provides such a device.
SUMMARY OF THE INVENTION
A laser energy delivery catheter for lateral transmission of laser energy in a liquid medium is contemplated by the present invention. Laser energy is transmitted through an optical fiber to a prism with a relatively high index of refraction relative to the surrounding liquid medium. Within the prism, laser energy is reflected from a beveled reflecting surface of the prism and directed laterally. A liquid interface between the distal end of the optical fiber and the proximal end of the prism is provided to reduce laser energy coupling losses at the interface when the device is in use.
A device embodying the present invention provides increased efficiency and reliability since there is no need for a glass encapsulating sleeve. The liquid medium that surrounds the prism when the device is in use also cools the distal end of the optical fiber, the prism, and the tissue at the site of the medical procedure.
The present invention also provides for distinct advantages in manufacturability. The prism, instead of a triangular shape that is difficult to mount and orient inside a needle, cannula or housing, can be cut from a block of a material having a relatively high refractive index, such as silica doped with lead, barium, sodium, titanium, and other oxides, for example, SFL-57 from Schott Glass Technologies, Inc, Duryea, Pa., with a refractive index of 1.811 at 1060 microns, or synthetic sapphire, which has refractive index of 1.745 at 1060 microns, into an elongated, transparent rod having a rectangular cross section. The distal surface of the rod can be inclined at an angle or angles consistent with the critical angle required to provide total internal reflection of the incident radiant energy in a liquid medium laterally from the longitudinal axis of the catheter. When a transparent rod with a prism-shaped distal end is inserted into a matching recess in a housing, orientation of the prism relative to the fiber optic can be positively and easily controlled.
A catheter embodying the present invention includes an elongated, substantially cylindrical housing that defines a recess for a prism or "rod bearing prism", a confined flow passageway for a liquid medium, a sidewall aperture, a prism mounted in the housing, and a fiber optic positioned to deliver laser energy to the prism.
The distal end of the fiber optic is also mounted in the cylindrical housing, and the proximal end of the fiber optic is adapted for coupling to a laser source. The prism may abut or be spaced from the distal end of the fiber optic and is positioned to receive a laser beam emitted by the fiber optic at its distal end, and to direct the emitted beam outwardly through the sidewall aperture in the housing. The refractive index of the prism is higher than that of the fiber optic and of the liquid medium that serves to optically couple the fiber optic to the prism as well as to cool the prism while the catheter is in use. Use of a liquid between the emitting surface of the fiberoptic and the receiving surface of the prism substantially reduces the reflection losses therefrom.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings,
FIG. 1 is a perspective view showing the distal end of a laser energy delivery catheter embodying the present invention;
FIG. 2 is a partially exploded perspective view of the device shown in FIG. 1;
FIG. 3 is a further exploded perspective view of the device shown in FIG. 1;
FIG. 4 is a side elevational view showing the device of FIG. 1 in section;
FIG. 5 is a plan view showing the device of FIG. 1 in section;
FIG. 6 is a sectional view taken along plane 6--6 in FIG. 4;
FIGS. 7(a) and 7(b) illustrate alternative prism configurations;
FIG. 8 illustrates a ray trace for the fiber and the high index prism;
FIG. 9 illustrates a prism similar to that of FIG. 8 but with the addition of a collimating lens on the input surface;
FIG. 10 illustrates a prism similar to that of FIG. 8 but with a recess in the input surface of the prism adapted to receive the distal end of a fiber optic;
FIG. 11 illustrates another embodiment of the current invention;
FIG. 12 shows an embodiment similar to that of FIG. 11 but with the addition of forced coaxial irrigation;
FIG. 13 shows the cross sectional view taken at plane 13--13 in FIG. 12;
FIG. 14 shows another embodiment of a suitable high index prism;
FIG. 15 is a side elevational view of the prism utilized in the embodiment shown in FIG. 11; and
FIG. 16 is a side elevational view of an alternate prism that can be used in practicing the present invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
The present laser delivery catheter can be used in a body lumen, organ, cavity or a surgically created passageway, where it is advantageous to apply laser energy laterally relative to the catheter's longitudinal axis. The present device is suitable for coagulating, cutting or ablating tissue, cartilage or other substances. Accordingly, the present device has utility in medical applications, such as urology, gynecology, general surgery, orthopedics, ophthalmology and other surgical procedures.
Referring to the drawings, FIG. 1 shows a catheter distal end 10 which is a substantially cylindrical housing constituted by frame 12 and hollow cap 14. Frame 12 is mounted to flexible tubing 16, through which optical fiber 20 extends. Hollow cap 14 is provided with sidewall aperture 18. Hollow cap 14 together with frame 12 and tubing 16 define a housing or recess for the prism and optical fiber 20, as well as a confined flow passageway for a liquid medium, such as water or saline, that may also serve as an optical coupling medium as well as a cooling medium and/or irrigation medium when the catheter embodying the present invention is in use. The flow of liquid medium (i.e., water or saline) through the catheter housing and out through sidewall aperture 18 is indicated by series of connected arrows.
Referring to FIGS. 2 and 3, frame 12 is a hollow, apertured tubular member having a cylindrical body portion 22, collar 24 that surrounds body portion 22 at one end thereof, and grips or leafs 26 and 28 that extend away from collar 24 toward the distal end of the catheter. Leafs 26 and 28 hold prism 30 therebetween, and are received within hollow cap 14. Leafs 26 and 28 as well as hollow cap 14 are in an interference fit in relationship with one another. If desired, cap 14 can be adhesively secured to leafs 26 and 28 or welded thereto.
There are four struts connecting the cylindrical body portion 22 and the collar 12. Three of these struts are shown in FIG. 2. Struts 34, 36 and 38 form a bridge between the body portion 22 and the collar 24 of frame 12. The fourth strut is not visible. In addition, these struts form four apertures, of which two are shown in FIG. 2. Apertures 50 and 52 allow the liquid medium (i.e., water or saline) to flow between the cylindrical body portion 22 and into the space defined by the two leaflets. Aperture 54 is formed between leaf 26 and 28 and collar 24. The liquid medium flows out of the two sides of the aperture 54 and across the input and reflective surfaces of the prism 30.
Fiber optic 20 extends into the cylindrical body portion 22 and is mounted thereto as will be described in greater detail hereinbelow.
As best seen in FIGS. 4, 5 and 6, the distal end of fiber optic 20 extends into the space defined, in part, by hollow cap 14 and is spaced from prism 30. The spacing between distal end face 42 of fiber optic 20 and input or incident face 44 of prism 30 is determined by shoulders 46 and 48 at the base of leafs 26 and 28, respectively. The spacing between the prism 30 and the distal end face 42 of fiber optic 20 is determined in part by the desired width of the emitted laser beam. Usually the spacing is in the range of about 5 to about 20 mils (125 μm to 510 μm), preferably about 10 mils to about 15 mils (255 μm to 350 μm).
FIG. 6 is the cross sectional view taken along plane 6--6 of FIG. 4. Apertures 50, 51, 52 and 53 are formed in between the strut pairs (34, 40) (38, 40) (34, 36) and (36, 38) respectively. The fiberoptic is centered within the aforementioned struts.
Apertures 50, 52 and 54 in frame 12 define liquid pathways for the liquid medium within cylindrical body portion 22.
Prism 30 can be synthetic sapphire (refractive index 1.745), (SFL-57; refractive index about 1.811), amorphous glass containing Ge, As and Se (AMTIR-1; refractive index 2.51), and the like.
The external dimensions of the catheter distal end, i.e., the cylindrical housing, can vary depending upon the desired end use of the catheter. For use in body lumens, the outside diameter of the cylindrical housing usually is in the range of about 0.5 to about 4 millimeters, preferably about 1 to about 2.5 millimeters. Prism 30 can have a flat or curved input face, output face and reflecting surface. If the aforementioned surfaces are flat, the ultimate divergence of the emitted beam from the prism will be determined by the divergence out of the fiberoptic and the angle of emission out of the output face. Consequently the spot size of the beam at a given distance from the emitting surface of the prism will also be determined largely by the divergence of the beam out of the fiber.
In one embodiment of the invention, as shown in FIG. 7(a), the totally internal reflecting (TIR) surface 55 of the prism 57 can be rounded to form a convex physical surface. This convex physical surface will act as a concave TIR surface which will increase the effective divergence of the laser beam. The plane of the arc defined by such curvature will need to be parallel to the emitting face of the prism in order to laterally reflect substantially all of the incoming light beam.
Alternatively, as shown in FIG. 7(b), the emitting surface 56 of the prism 58 can be rounded to form a convex physical surface to achieve the same diverging effect.
The aforesaid increased divergence of the beam will increase the spot size formed at a fixed distance from the tip of the catheter and reduce the energy density thereof, compared to the embodiment incorporating a prism with either a flat reflective surface or a flat emissive surface. The increased divergence may have beneficial effects by creating a substantially coagulative effect, instead of an ablative effect, due to the lower energy density.
FIG. 8 shows the propagation of light rays into and out of the high index prism. The angle at which these light rays travel within the prism is shown as α and can be calculated by (1) ##EQU1## where n 1 is the index of refraction of the surrounding medium, n 2 is the index of refraction of the prism and θ is the angle between the most divergent ray exiting the fiber and the normal to the input surface of the prism.
The prism is cut at angle β with respect to the output face of the prism. Angle β can be found by
β=90-θc-α (2)
where θc is the critical angle of the prism liquid interface and can be calculated by (3) ##EQU2##
For example, for the case of SFL57 (n 2 =1.811 at 1060 nm) in a water environment (n=1.33) and with a fiber of numerical aperture (NA)=0.22 (θ=9.55 degrees) β is found to be 35.75 degrees, while α is equal to 6.99 degrees. Fixing β at 35.75 degrees and substituting -6.99 degrees and +6.99 degrees for α, Γ 1 and Γ 2 are found to be 74.2 and 54.0 degrees respectively. Equation (4) is used to calculate the emission angles. ##EQU3##
FIG. 9 shows another embodiment of the current invention, in which a convex surface has been formed on the input end of the prism 30. The convex surface acts as a lens and serves to collimate the light energy emitted from the fiberoptic distal end 42. Consequently the angle at which such rays travel through the material would be reduced and that would allow the angle Γ to be closer to the critical angle θc. This would result in the final angles of emission to be closer to 90 degrees.
If desired, as shown in FIG. 10, a recess can be provided in the incident face of the prism, and the distal end of the fiber optic may be positioned therewithin, so as to reduce scattering and attendant energy losses.
Another embodiment of the present invention is shown in FIG. 11, where catheter device 60 comprises prism 62 and fiber optic 64 mounted to housing 66, which can consist of two halves welded or glued together. Fiber optic 64 is spaced from prism 62. Housing 66 is hollow, defines a confined flow passageway for an ambient liquid medium, e.g., water or saline, and is provided with apertures 68 and 70 that permit the liquid medium to pass therethrough. The proximal end of fiber optic 64 is adapted for coupling to a laser source. Liquid medium within housing 66 provides optical coupling of fiber optic 64 to prism 62 which has a refractive index that is sufficiently higher than the refractive index of the surrounding liquid medium to permit total internal reflection of the light energy to occur. Housing 66 is secured to fiber optic 64 by crimping sleeve 72 unitary with housing 66 or, optionally, by an adhesive such as epoxy resin or the like, or both.
Prism 62 is rod-shaped and is made of a transparent material such as synthetic sapphire, which has (a) an index of refraction sufficiently high to cause laser energy transmitted thereinto to be emitted substantially laterally from the longitudinal axis thereof when surrounded by a given liquid medium and (b) a melting point sufficiently high to preclude melting or other damage thereto when in direct contact with tissue during lasing.
This embodiment can be used (a) in a non-contact mode, directing laser energy laterally in a fluid medium from prism 62 into the target tissue to coagulate the same to a chosen depth, which tissue will slough-off or be absorbed by the body over a period of several weeks, as well as, after coagulation of the tissue in the manner described in (a) above, (b) in a contact mode to vaporize or ablate tissue by placing the distal tip of prism 62 directly in contact with the tissue, thereby immediately removing a portion of the coagulated tissue constricting or obstructing a body lumen or cavity. The distal tip of the prism 62 can be rounded to minimize the risk of breakage and damage to body tissues.
In the case of benign enlargement of the prostate, deep coagulation of the prostate gland using the present device in a non-contact mode will, over a period of weeks, restore urine flow, as the coagulated tissue is sloughed-off. However, even though a small amount of tissue may be vaporized during the lasing, due to edema (swelling) of tissue as a result of the coagulation procedure, a drainage tube must be inserted and worn with a urine collection bag by the patient for a period of several days, as the patient would otherwise be unable to urinate. Following the coagulation procedure described above, the device described in this embodiment can be used in contact mode to remove a desired amount of coagulated tissue without bleeding, to offset the edema, and to enable the patient to either (a) immediately urinate without the need for a drainage tube or (b) wear a drainage tube for a substantially shorter period of time before being able to urinate normally.
Prism 62 can be made from a square or rectangular cross section rod, as well as from a cylindrical or oval rod, whose distal end has been beveled at an aforementioned angle β. To insure that prism 62 is not dislodged from housing 66 depressions 67 can be cut in the outer surfaces of prism 62, and ridges 69 of housing 66 matchingly engage therewith. Side elevation contour of prism 62 is shown in FIG. 15.
As seen in FIG. 12, flexible catheter 76 is adhesively attached to frame 78. Fiber optic 74 is secured to sleeve 79 that extends rearwardly from frame 78. Fluid flow through apertures 71, 74 in frame 78 is indicated by connected arrows.
FIG. 13 shows the cross sectional view along plane 13--13 of FIG. 12. A square cross section prism 62 housed within the tubular housing 66 defines passageways 73 through which the liquid medium can flow.
The distal end of the prism can have various shapes. For example, as seen in FIG. 16, by utilizing a ball-tipped optical fiber 82 which has been beveled to the desired angle for total internal reflection, resulting prism 84 is less traumatic to tissue and the risk of breakage can be reduced.
Referring to FIG. 14, the distal tip of prism 62 (FIG. 11) can be frosted by means known in the art or coated with a layer of light absorbing material 80, such as charcoal or a ceramic, to convert the light energy to heat for ablation or coagulation of tissue in contact therewith.
The foregoing description and the drawings are intended as illustrative and are not to be taken as limiting. Still other variations and rearrangements of parts are possible and will readily present themselves to those skilled in the art.
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A laser energy delivery catheter emits energy laterally relative to the longitudinal axis of the catheter. The catheter distal end is a cylindrical housing provided with a sidewall aperture. Within the housing is mounted a prism spaced from the distal end of a fiber optic. The refractive index of the prism is higher than the refractive indices of the fiber optic and the coupling liquid medium. A liquid medium is utilized to cool the device when in use, and may also be utilized to optically couple the fiber optic and the prism. The catheter can be configured as a rigid or semi-rigid, hand held surgical instrument, or as a flexible device that can be inserted into body lumens through an endoscope.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method and system for removing oil and gasoline from an engine.
2. Description of Related Art
It is common for small four stroke engines used in outdoor power equipment, such as lawn mowers, edgers, chippers, generators, and power washers, to be manufactured in dedicated factories that are remote from the final assembly plant. The completed engines are then periodically shipped to the final assembly plant.
Manufacturers of power equipment often require that the engines be started prior to shipment. This helps insure that the engines will work when they are ultimately assembled into the power equipment. Therefore, the engine manufacturer must include means for starting the engines prior to shipment, which entails filling the engine crankcase with oil and at least partially filling the fuel tank with gasoline.
Thereafter, in order to prevent spills and leaks, the engines must be drained of gasoline and oil before being packaged for shipment. Due to the viscosity of oil and the speed at which the engines must be drained, it has heretofore proven necessary to use a pump to evacuate oil and gasoline from the engines. The pumped-out oil and gasoline is directed toward an oil recovery tank and a gas recovery tank, respectively, for recycling and/or re-use.
In the past, oil and gas have been pumped out of the engine by pumps that are in the flow line between the crankcase and the oil recovery tank, in the case of oil, or in the flow line between the fuel tank and the gas recovery tank, in the case of gasoline. However, this prior art method and system has proven unreliable as the pumps have required relatively frequent maintenance and repair. It is believed that oil and gasoline damage the pump seals, resulting in leakage problems, frequent repair, and excessive downtime.
Therefore, there exists a need in the art for a method and system for quickly and reliably removing oil and gasoline from an engine.
SUMMARY OF THE INVENTION
The present invention is directed toward an improved method and system for removing oil and gasoline from an engine.
In accordance with the present invention, a system for removing liquid from an engine includes a first liquid storage tank, a second liquid storage tank, a return tank, a vacuum source, and a pressurized air source. Fluid communication between the tanks and the pressure and vacuum sources is controlled by a controller that actuates valves in response to sensed liquid levels in the first and second liquid storage tanks.
In further accordance with the present invention, a first conduit, which is adapted for insertion into an engine reservoir that contains liquid to be removed, provides liquid to the first liquid storage tank. A second conduit extends between and fluidly interconnects the first and second liquid storage tanks. A first control valve is disposed in the second conduit and serves to control fluid communication therethrough.
In further accordance with the present invention, the vacuum source establishes a vacuum or sub-atmospheric pressure in the first and second liquid storage tanks while the pressurized air source selectively communicates pressurized or over-atmospheric pressure air to the second liquid storage tank. Preferably, vacuum is continuously provided to the first liquid storage tank while pressurized air and vacuum are supplied to the second liquid storage tank in a mutually exclusive fashion.
In accordance with other aspects of the invention, sensors are provided for sensing liquid levels in the first and second liquid storage tanks. Also, a controller actuates the first and second valves and controls communication of pressurized air from said pressure source, in response to sensed liquid levels.
The present invention also teaches a method for removing liquids from an engine reservoir. The method includes communicating vacuum to the first and second liquid storage tanks and inserting a nozzle of a first conduit into the engine reservoir. The first conduit includes a nozzle valve for controlling communication of liquid from the engine reservoir to the first liquid storage tank via the first conduit.
In further accordance with the method, a first control valve is placed in a first position to permit liquid to flow from the first liquid storage tank to the second liquid storage tank. The level of liquid in the first and second liquid storage tanks is monitored.
In further accordance with the inventive method, when the liquid level in the second liquid storage tank reaches a first predetermined level, the first control valve is placed in a second position to prevent liquid flow from the first liquid storage tank to the second liquid storage tank, communication of vacuum sub-atmospheric pressure air to the second liquid storage tank is discontinued, and pressurized or over-atmospheric pressure air is communicated to the second liquid storage tank to force liquid therein to flow through the third conduit toward the return tank.
In accordance with another aspect of the method, when the liquid level in one of the first and second liquid storage tanks reaches a second predetermined level, the communication of over-atmospheric pressure air to the second liquid storage tank is discontinued, communication of sub-atmospheric pressure air to the second liquid storage tank is reestablished, and the first control valve is returned to the first position to permit liquid to flow from the first liquid storage tank to the second liquid storage tank.
BRIEF DESCRIPTION OF THE DRAWINGS
These and further features of the invention will be apparent with reference to the following description and drawings, wherein:
FIG. 1 is a schematic diagram of a system according to a first preferred embodiment of the present invention;
FIG. 2 is a schematic diagram of a system according to a second preferred embodiment of the present invention;
FIG. 3 is a flow chart illustrating operating steps using the first embodiment of the present invention; and,
FIG. 4 is a flow chart illustrating operating steps using the second embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
With reference to FIG. 1, a first preferred embodiment of a system according to the present invention is illustrated. The system includes a first liquid storage tank 10 , a second liquid storage tank 12 , a return tank 14 , a first control valve 16 , a second control valve 18 , a pressure source 20 , a vacuum source 22 , and a series of conduits 24 , 26 , 28 , 30 , 32 , 34 .
The first liquid storage tank 10 is connected to an outlet 24 a of a first conduit 24 , which serves as a liquid inlet and includes an inlet nozzle 24 b having a manually-operated inlet nozzle valve (not shown). The first conduit 24 has a check valve 24 c disposed therein to prevent reverse flow therethrough. The inlet nozzle 24 b is designed for insertion into an engine reservoir, such as a crankcase or fuel tank, and the nozzle valve is opened and closed by a user to permit communication of suction to the inlet nozzle 24 b and thereby withdraw liquids from the engine reservoir. Liquids flowing through the inlet conduit 24 are delivered to the first liquid storage tank 10 .
The first liquid storage tank 10 is fluidly connected to the second liquid storage tank 12 via a second conduit 26 and is connected to the vacuum source 22 via a first vacuum conduit 28 . Preferably, the second conduit 26 is connected, at opposite ends, to bottom ends of the first and second liquid storage tanks 10 , 12 , respectively. The second conduit 26 has the first control valve 16 disposed therein to control liquid flow through the second conduit 26 from the first liquid storage tank 10 toward the second storage tank 12 . The first control valve 16 is movable between a first position establishing fluid communication between the first and second liquid storage tanks 10 , 12 and a second position blocking fluid communication between the storage tanks 10 , 12 .
The first vacuum conduit 28 is connected to a top of the first liquid storage tank 10 . A flow director or shield 10 a is preferably provided within the first liquid storage tank 10 to prevent liquid from being drawn through the first vacuum conduit 28 . A first float-type switch 10 b is secured to the first liquid storage tank 10 at a predetermined location between the top and bottom ends thereof. Naturally, it is considered apparent that means other than the first float-type switch 10 b disclosed herein may be used with equal functionality without departing from the scope and spirit of the present invention.
The second liquid storage tank 12 is disposed vertically below the first liquid storage tank 10 and receives liquids from the first liquid storage tank 10 by means of the second conduit 26 and the first control valve 16 . The second liquid storage tank 12 is also connected to the return tank 14 by means of an outlet conduit 36 . Preferably, a check valve 36 a is disposed in the outlet conduit 36 , as illustrated, to prevent reverse flow of liquid in the outlet conduit 36 .
The second liquid storage tank 12 is also connected to the vacuum source 22 and to the pressure source 20 by means of the second control valve 18 , a second vacuum conduit 32 , a first pressure conduit 30 , and a common conduit 34 . More specifically, and as illustrated in FIG. 1, the second vacuum conduit 32 and first pressure conduit 30 connect the vacuum and pressure sources 22 , 20 , respectively, to inlets of the second control valve 18 , while the common conduit 34 extends from an outlet of the second control valve 18 to the second liquid storage tank 12 . The second control valve 18 is selectively movable between a first position establishing communication between the vacuum source 18 and the second liquid storage tank 12 and a second position establishing communication between the pressure source 20 and the second liquid storage tank 12 .
A second float-type switch 12 a is secured to the second liquid storage tank 12 at a vertical location that is relatively between the top and bottom ends of the tank 12 . As noted hereinbefore, it is considered apparent that means other than the second float-type switch 12 a disclosed herein may be used with equal functionality without departing from the scope and spirit of the present invention.
A controller 38 is provided to control operation of the first and second control valves 16 , 18 in response to the volume of liquid in each of the first and second liquid storage tanks 10 , 12 as sensed by the first and second float-type switches 10 b, 12 a. The system of the present invention is intended for use as part of a manufacturing process wherein, following starting of the engines, the oil and gasoline therein must be evacuated to facilitate subsequent handling and shipment of the engine. In that light, and keeping in mind that the oil and gasoline evacuation systems are maintained separately, operation of the system will be described hereinafter with reference to the flow chart of FIG. 3 and the foregoing description of the system.
The description of the operation of the system presumes an initial condition wherein the first control valve 16 is in the first position establishing communication between the first and second liquid storage tanks 10 , 12 and the second control valve 18 is in the first position establishing communication between the vacuum source 22 and the second liquid storage tank 12 . As such, under-atmospheric pressure is provided to the first and second liquid storage tanks 10 , 12 . When an engine to be evacuated is brought to the system, the inlet nozzle 24 b is inserted into the engine reservoir (i.e., crankcase or fuel tank) and the inlet nozzle valve is opened to draw the liquid through the first conduit 24 and into the first liquid storage tank 10 . The liquid subsequently flows, at least partly due to gravity, through the second conduit 26 and first control valve 16 and into the second liquid storage tank 12 , and begins filling the second liquid storage tank 12 (step 200 ).
This continues until, after a number of engine reservoirs are emptied, the second liquid storage tank 12 fills to the point that the second float-type switch 12 a is actuated. This causes the controller 38 to move the first and second control valves 16 , 18 from their first position to their second position. Moving the first control valve 16 to it's second position blocks communication between the first and second liquid storage tanks 10 , 12 . Placing the second control valve 18 in its second position places the pressure source 20 in communication with the second liquid storage tank 12 , and thereby establishes an over-atmospheric pressure in the second liquid storage tank 12 . The pressure thus established above the liquid in the second storage tank 12 forces the liquid in the second storage tank 12 to flow through outlet conduit 36 and into the return tank 14 , emptying the second storage tank 12 (step 202 ).
While the second storage tank 12 is being emptied, under-atmospheric pressure is still communicated to the first liquid storage tank 10 , and the system continues to be used for evacuating engine reservoirs. Since the first control valve 16 is closed, the liquid evacuated from the engine reservoirs is retained in the first liquid storage tank 10 . After a number of engine reservoirs are emptied, the first float-type switch 10 b is actuated, causing the controller 38 to move the first and second control valves 16 , 18 from their second positions back to their first positions. Moving the second control valve 18 to the first position removes pressure from the second liquid storage tank 12 , and communicates under-atmospheric pressure or vacuum to the second liquid storage tank 12 . Moving the first control valve 16 to the first position reestablishes fluid communication between the first and second liquid storage tanks 10 , 12 , and therefore permits liquid to again flow through the second conduit 26 and first control valve 16 (from the first liquid storage tank 10 to the second liquid storage tank 12 ; return to step 200 ).
Naturally, it is contemplated that a vent may be provided such that the second liquid storage tank 12 will be briefly vented to atmosphere when switched from the pressure source 20 to the vacuum source 22 . Moreover, it is contemplated that a brief time delay may be provided by the controller 38 wherein the second control valve 18 may return to it's first position shortly before the first control valve 16 returns to it's first position.
Following return of the control valves 16 , 18 to their first positions, the second liquid storage tank 12 fills with liquid previously contained in the first liquid storage tank 10 , as well as liquid added to the system from subsequently evacuated engine reservoirs. The system thus continues filling the second liquid storage tank 12 and then, while draining the second liquid storage tank 12 into the return tank 14 , filling the first liquid storage tank 10 . As will be apparent to those skilled in the art, the available volumes of the first and second liquid storage tanks 10 , 12 (i.e., the volumes available before the associated float-type limit switches 10 b, 12 a are actuated) may be selected within wide limits and, for example, can be selected or tuned to the expected throughput of the system based upon the available space for the first and second liquid storage tanks 10 , 12 in the manufacturing environment. Preferably, the tank sizes are selected such that, considering normal operating cycles, the second liquid storage tank 12 is completely emptied before the first liquid storage tank 10 is filled, and such that the available volume of the first liquid storage tank 10 may be completely received within the available volume of the second liquid storage tank 12 .
With reference to FIG. 2, a second preferred embodiment of the present invention is illustrated. The second preferred embodiment differs from the first embodiment described hereinbefore by providing dedicated control valves for controlling communication of vacuum or sub-atmospheric pressure and pressurized or over-atmospheric pressure air to the second liquid storage tank, as will be apparent from the following description.
The system according to the second embodiment includes a first liquid storage tank 110 , a second liquid storage tank 112 , a return tank 114 , a first control valve 116 , a second control valve 118 , a third control valve 119 , a pressure source 120 , a vacuum source 122 , and a series of conduits 124 , 126 , 128 , 130 , 132 , 134 .
The first liquid storage tank 110 is connected to an outlet 124 a of a first conduit 124 , which serves as a liquid inlet and includes an inlet nozzle 124 b having an inlet nozzle valve (not shown). The first conduit 124 has a check valve 124 c disposed therein to prevent reverse flow therethrough. The inlet nozzle 124 b is designed for insertion into an engine reservoir, such as a crankcase or fuel tank, and the nozzle valve is opened and closed by a user to permit communication of suction to the inlet nozzle 124 b and thereby withdraw liquids from the engine reservoir. Liquids flowing through the inlet conduit 124 are delivered to the first liquid storage tank 110 .
The first liquid storage tank 110 is fluidly connected to the second liquid storage tank 112 via a second conduit 126 and is connected to the vacuum source 122 via a first vacuum conduit 128 . Preferably, the second conduit 126 is connected at one end to a bottom of the first liquid storage tank 110 and, at the other end, to the top of the second liquid storage tank 112 , as illustrated. The second conduit 126 has a first control valve 116 disposed therein to control liquid flow through the second conduit 126 from the first liquid storage tank 110 toward the second storage tank 112 . The first control valve 116 is movable between a first position establishing fluid communication between the first and second liquid storage tanks 110 , 112 and a second position blocking fluid communication between the storage tanks 110 , 112 .
The first vacuum conduit 128 is connected to a top of the first liquid storage tank 110 . A first liquid level sensor 110 b is associated with the first liquid storage tank 110 and serves to sense the level of liquid therein. In this embodiment the sensor is preferably a scale-type sensor that monitors the weight of the first liquid storage tank 110 . Such a sensor arrangement may be more reliable, over time, in challenging environments. Naturally, it is considered apparent that means other than the illustrated and preferred sensor may be used with equal functionality without departing from the scope and spirit of the present invention.
The second liquid storage tank 112 is disposed vertically below the first liquid storage tank 110 and receives liquids from the first liquid storage tank 110 by means of the second conduit 126 and the first control valve 116 . The second liquid storage tank 112 is also connected to the return tank 114 by means of an outlet conduit 136 that extends from a bottom of the tank 112 . Preferably, a check valve 136 a is disposed in the outlet conduit 136 , as illustrated, to prevent reverse flow of liquid in the outlet conduit 136 .
The second liquid storage tank 112 is also connected to the vacuum source 122 and to the pressure source 120 . More specifically, and as illustrated in FIG. 2, the vacuum source 122 is connected to the second liquid storage tank 112 by means of the second control valve 118 , a second vacuum conduit 132 , and a common conduit 134 while the pressure source 120 is connected to the second liquid storage tank 112 by means of the third control valve 119 , a pressure conduit 130 , and the common conduit 134 .
The second and third control valves 118 , 119 are dedicated to controlling communication from the pressure and vacuum sources 120 , 122 , respectively. However, as will be appreciated from the following description, the second and third control valves 118 , 119 are operated by the controller 138 in a synchronous fashion. As such, the second control valve 118 is movable between a first position wherein the vacuum source 122 is in communication with the second liquid storage tank 112 and a second position wherein the vacuum source 122 is not in communication with the second tank. Similarly, the third control valve 119 is movable between a first position wherein communication of pressurized air from the pressure source 120 to the second liquid storage tank 112 is prevented and a second position wherein the pressure is communicated to the second liquid storage tank 112 . When the second control valve 118 is in it's first position the third valve 119 is in it's first position and, when the second control valve 118 is in it's second position the third valve 119 is in it's second position.
The second liquid storage tank 112 also has a scale-type sensor/transducer 112 a wherein the level of liquid in the tank is correlated to the weight of the tank. As noted hereinbefore, it is considered apparent that means other than the scale-type sensor 112 a may be used with equal functionality without departing from the scope and spirit of the present invention.
A controller 138 is provided to control operation of the first, second, and third control valves 116 , 118 , 119 in response to the volume of liquid in each of the first and second liquid storage tanks 110 , 112 as sensed by the sensors 110 b, 112 a. Operation of the system will be described hereinafter with reference to the flow chart of FIG. 4 and the foregoing description of the system.
The description of the operation of the system presumes an initial condition wherein the first control valve 116 is in the first position establishing communication between the first and second liquid storage tanks 110 , 112 , the second control valve 118 is in the first position establishing communication between the vacuum source 122 and the second liquid storage tank 112 , and the third control valve 119 is in the first position preventing communication between the pressure source 120 and the second liquid storage tank 112 . As such, under-atmospheric pressure is provided to the first and second liquid storage tanks 110 , 112 . When an engine to be evacuated is brought to the system, the inlet nozzle 124 b is inserted into the engine reservoir (i.e., crankcase or fuel tank) and the inlet nozzle valve is opened to draw the liquid through the first conduit 124 and into the first liquid storage tank 110 . The liquid subsequently flows, at least partly due to gravity, through the second conduit 126 and first control valve 116 and into the second liquid storage tank 112 , and begins filling the second liquid storage tank 112 (step 300 ).
After a number of engine reservoirs are emptied in the aforementioned manner, the second liquid storage tank 112 fills to the point that the scale-type sensor/transducer 112 a is actuated, indicative of a predetermined volume/weight of liquid in the second tank 112 . The controller 138 actuates the first, second, and third control valves 116 , 118 , 119 to move from their first positions to their second positions. Moving the first control valve 116 to it's second position blocks fluid communication between the first and second liquid storage tanks 110 , 112 . Placing the second control valve 118 in its second position disconnects the vacuum source 122 from the second liquid storage tank. Moving the third control valve 119 to the second position places the pressure source 120 in communication with the second liquid storage tank 112 , and thereby establishes an over-atmospheric pressure in the second liquid storage tank. 112 . The pressure thus established above the liquid in the second storage tank 112 forces the liquid in the second storage tank 112 to flow through outlet conduit 136 and into the return tank 114 , emptying the second storage tank 112 (step 302 ).
While the second storage tank 112 is being emptied, under-atmospheric pressure is still communicated to the first liquid storage tank 110 , and the system continues to be used for evacuating engine reservoirs. Since the first control valve 116 is closed, the liquid evacuated from the engine reservoirs is retained in the first liquid storage tank 110 . After a number of engine reservoirs are emptied, the first scale-type sensor/transducer 110 b is actuated, indicative of a predetermined volume/weight of liquid in the first tank, and thereby causes the controller 138 to move the first, second, and third control valves 116 , 118 , 119 from their second positions back to their first positions. Moving the third control valve 119 to the first position disconnects pressure from the second liquid storage tank 112 , while moving the second control valve 118 to the first position communicates under-atmospheric pressure or vacuum from the vacuum source 122 to the second liquid storage tank 112 . Moving the first control valve 116 to the first position re-establishes fluid communication between the first and second liquid storage tanks 110 , 112 , and therefore permits liquid to again flow through the second conduit 126 and first control valve 116 (from the first liquid storage tank 110 to the second liquid storage tank 112 ; return to step 300 ).
As with the first embodiment, it is contemplated that a vent may be provided such that the second liquid storage tank 112 will be briefly vented to atmosphere when switched from the pressure source 120 to the vacuum source 122 . Moreover, it is contemplated that a brief time delay may be provided by the controller 138 wherein the second control valve 118 may return to it's first position shortly before the first control valve 116 returns to it's first position.
Following return of the control valves 116 , 118 to their first positions, the second liquid storage tank 112 fills with liquid previously contained in the first liquid storage tank 110 , as well as liquid added to the system from subsequently evacuated engine reservoirs. The system thus continues filling the second liquid storage tank 112 and then, while draining the second liquid storage tank 112 into the return tank 114 , filling the first liquid storage tank 110 . As will be apparent to those skilled in the art, the available volumes of the first and second liquid storage tanks 110 , 112 (i.e., the volumes available before the associated float-type limit switches 110 b, 112 a are actuated) may be selected within wide limits and, for example, can be selected or tuned to the expected throughput of the system based upon the available space for the first and second liquid storage tanks 110 , 112 in the manufacturing environment. Preferably, the tank sizes are selected such that, considering normal operating cycles, the second liquid storage tank 112 is completely emptied before the first liquid storage tank 110 is filled, and such that the available volume of the first liquid storage tank 110 may be completely received within the available volume of the second liquid storage tank 112 .
Moreover, although actuation of the control valves 116 , 118 , 119 by the controller 138 has been described hereinbefore as being in response to both the first and second scale-type sensors/transducers 110 b, 112 a, it is contemplated that it could instead be in response to only the second sensor 112 a, and the first sensor 110 b could be provided as a fail-safe to prevent overflow of the first liquid storage vessel 110 .
The present invention has been described herein with particularity, but it is noted that the scope of the invention is not limited thereto. Rather, the present invention is considered to be possible of numerous modifications, alterations, and combinations of parts and, therefore, is only defined by the claims appended hereto. For example, it is contemplated that, with reference to the first embodiment, instead of using the first float-type switch to control the valves, a third float-type switch may be provided in the second liquid storage tank to sense absence of liquid in the second tank, which is indicative of the second tank's availability to receive liquid from the first liquid storage tank. In this case, the first float-type switch would be used as a system shut-down upon threatened overflow of the first liquid storage tank, as may occur during a problem in draining of the second tank or malfunction of the third float-type switch.
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A system and method for removing liquids from engines, the system including first and second liquid storage tanks that are disposed for serial flow therebetween, a pressure source, and a vacuum source. The first liquid storage tank is continuously connected to the vacuum source, while the second liquid storage tank is alternatively connected to either the vacuum source, during filling, or the pressure source, during draining. Opening and closing the valves is controlled in response to sensed liquid levels in the tanks.
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FIELD OF THE INVENTION
This invention relates to a process for removing particulate matter from a non-dissoluble sand control pack which contains granulated ceramic material used in the production of hydrocarbonaceous fluids from a subterranean formation.
BACKGROUND OF THE INVENTION
Recovery of formation fluid such as petroleum fluid from a subterranean formation is frequently difficult when the subterranean formation is comprised of one or more incompetent or unconsolidated sand layers or zones. Sand particles in the incompentent or unconsolidated sand zone move or migrate into the wellbore during recovery of formation fluids from that zone or sand particles move away from the well during injection of secondary or tertiary recovery fluids into the formation. When fluids are recovered from the formation, the movement of sand into the wellbore can cause the well to cease production of fluids from said formation. Also, small sand particles can plug small openings in porous masses formed around the wellbore for the purpose of restraining the flow of sand, such as screens or slotted liners which are frequently placed in wells for this purpose. Not only can fluid production be reduced or even stopped altogether, if sand particles flow through the well to the surface, considerable mechanical problems can result from passage of abrasive sand particles through pumps and other mechanical devices.
In order to obtain extended life of sand control packs in hostile environments where hot temperatures and high pressures are encountered, granulated ceramic materials have been utilized for sand pack control purposes. These granulated ceramic sand packs have extended long life periods when utilized in these hostile environments during the production of hydrocarbonaceous fluids from the formation. However, it has been necessary to remove the production stem with the gravel pack attached thereto from the formation in order to clear accumulated particulate matter such as sand and formation fines therefrom. Therefore, what is needed is a method for removing accumulated particulate matter from a non-dissoluble sand control pack in-situ so as to minimize production down time and loss of revenues.
SUMMARY OF THE INVENTION
This invention relates to a method for removing particulate matter from a non-dissoluble sand control pack which contains granulated ceramic material therein which pack is used to produce hydrocarbonaceous fluids from a subterranean formation. Prior to removing said particulate matter, production of hydrocarbonaceous fluid from said formation is ceased. Cessation of production can be accomplished by means known to those skilled in the art. One such method is to utilize a solidifiable gel material to preclude entry of hydrocarbonaceous fluids into the wellbore from the formation. In this manner the formation will not be unduly damaged when the solidified gel material is removed from the formation for resumption of production. After the production of hydrocarbonaceous fluid from said formation has been ceased, said sand control pack is contacted with a solution of a mineral acid of a strength and composition sufficient to react with said particulate matter. Upon reacting with the particulate matter, the acid removes said particulate matter and increases the porosity of said pack without damaging it. Once the particulate matter has been removed from said pack, it can be flushed with a solution sufficient to remove the acid from the wellbore and pack. Afterwards, production of hydrocarbonaceous fluids from the formation into the wellbore is resumed.
It is therefore an object of this invention to remove in-situ, particulate matter from a non-dissoluble sand control pack.
It is a further object of this invention to minimize production downtime when removing a sand control pack from the formation in order to remove particulate matter therefrom.
It is a yet further object of this invention to provide an inexpensive method for the in-situ removal of particulate matter from a sand control pack.
BRIEF DESCRIPTION OF THE DRAWINGS
The drawing is a schematic representation of a well having a non-dissoluble sand control pack therearound within a subterranean formation.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the practice of this invention, it is desired to remove particulate matter, e.g. sand and formation fines from a non-dissoluble sand control device. Such sand control devices are disclosed in U.S. Pat. Nos. 4,120,359 and 4,102,399 which issued on Oct. 17, 1978 and July 25, 1978, respectively, to Harnsberger. Said patents are incorporated herein by reference. These devices comprise a means for forming a heat resistant, non-dissoluble pack which resist the high heat eroding and dissolving effects of steam flooding. The pack is formed by a slurry of gravel comprising silicon carbide alone, or with garnet or zircon mixed therewith. The high heat resistant unconsolidated, permeable, non-dissoluble, and long-life sand control pack consists of the granular material silicon carbide alone, or with garnet or zircon mixed therewith for resisting dissolution thereof during a steamflood which minimizes migration of sand and other granular materials into the wellbore from the production zone of a hydrocarbonaceous-bearing formation. After the particulate matter has been removed by processing hydrocarbonaceous fluids therethrough, the sand control pack becomes packed or plugged with said particulate matter. This causes the production of hydrocarbonaceous fluids to be reduced and a loss of pack efficiency for the removal of particulate matter. When this happens, it is necessary to remove the particulate matter from said sand control pack.
Prior to removing said particulate matter, the productive interval of the formation must be "killed". The productive interval of the formation can be "killed" in several ways. One method of "killing" a productive interval of a well is to direct a "kill" fluid down through the wellbore and into the formation. Upon entry of said "kill" fluid into the formation, it causes a "drowning" of the productive interval of the formation. Once the productive interval of the formation has been "drowned", the sand control pack is contacted with a solution of hydrochloric acid of about 5 to about 28 volume % which is used as a preflush. Thereafter, a mixture of hydrochloric acid and hydrofluoric acid is contacted with said sand control pack to restore the pack's permeability. The mixture of hydrochloric and hydrofluoric acid should be in a ratio of about 12 volume % hydrochloric acid to about 3 volume % hydrofluoric acid. Of course, as will be understood by those skilled in the art, the ratio concentration of hydrochloric to hydrofluoric acid will vary depending upon the nature of the particulate matter to be removed from said sand control pack.
In the preferred embodiment as is shown in the drawing, a pumpable solidifiable gel mixture is directed into wellbore 12. Said gel mixture is allowed to flow down wellbore 12 into formation 10 until it comes in contact with the productive interval of formation 10. At the productive interval, said gel mixture enters the productive interval of formation 10 via perforations 16. Sufficient solidifiable gel material is allowed to enter said productive interval thereby closing off said interval to production of hydrocarbonaceous fluids, particularly oil. Additional solidifiable gel material is allowed to enter wellbore 12 which material contacts said productive interval until said gel has filled the wellbore 12 above the productive interval.
When the solidifiable gel material solidifies, it forms a solid gel plug 20 within wellbore 12. It also forms a solid formation gel 14 in the productive interval of formation 10. Gel plug 20 and solid formation gel 14, upon solidification, are of a composition and strength sufficient to withstand the temperatures and pressures encountered in formation 10 so as to exclude hydrocarbonaceous fluids from entering from the formation into wellbore 12.
As is preferred, the solidifiable gel material used in gel plug 20 and solid formation gel 14 should be of a composition sufficient to withstand a temperature range from about 300° F. to about 450° F. for at least about 0.5 of a day to about 4 days. A suitable solidifiable gel mixture can be obtained by mixing into the pumpable gel mixture a chemical known as an oxygen scavenger (such as sodium thiosulfate or short chain alcohols such as methanol, ethanol, and isopropanol), preferably sodium thiosulfate. The concentration of the oxygen scavenger utilized, of course, would depend upon the thermal stability desired to be obtained which varies with the characteristics of a particular formation. However, as is preferred, it is anticipated that the concentration of the oxygen scavenger in the pumpable gel mixture will be from about 0.10 percent by weight to about 0.75 percent by weight, preferably about 0.50 percent by weight. A method for making a suitable solidifiable gel material is disclosed in U.S. Pat. No. 4,605,061 which issued on Aug. 12, 1986 to Jennings, Jr. This patent is hereby incorporated by reference.
As is preferred, it is desired to remove gel plug 20 and formation gel 14 in two different ways. The gel plug as is preferred, can be removed by use of a mineral acid of a strength sufficient to liquify said gel and remove particulate matter from said sand control pack at the same time. Solid formation gel 14 should be composed of a solidifiable gel material containing a gel breaker. This gel breaker, included in the gel mixture, is selected from a group of chemical compounds which can break down a solid gel at temperatures of less than from about 60° F. to about 250° F. Generally this breakdown will occur from about two hours to about 24 hours depending upon the type and concentration of breaker added and thereby remove any remaining solidified gel after contacting said solid gel with said acid, whether said solid gel is the wellbore or the formation. As will be understood by those skilled in the art, the gel mixture should contain a gel breaker of a composition and strength sufficient to withstand the temperatures required in the formation where utilized.
Chemicals satisfactory for use as gel breakers, and which are incorporated into the gel mixture, include enzymes and oxidizing agents, suitable for breaking down the solid gel (such as sodium persulfate). Other gel breakers sufficient for this purpose are discussed in U.S. Pat. No. 4,265,311 which issued to Ely on May 5, 1981. This patent is hereby incorporated by reference. These chemicals are readily available from chemical suppliers and with the exception of enzyme breakers are sold under their chemical names. Enzyme breakers can be obtained from oil field service companies. The concentration of gel breaker incorporated into the gel mixture will vary from about 0.01 weight percent to about 0.10 weight percent, preferably about 0.05 weight percent of the gel mixture. When the solidified gel material has cooled to the desired temperature, the gel breaker will break down the solid gel causing it to liquefy and flow from formation 10.
Sufficient time should be allowed prior to the breakdown of the gel via said gel breakers to allow the solid plug 20 to be removed from the wellbore by use of mineral acids. The mineral acids utilized should be of a strength sufficient to liquefy the solid gel plug as well as to be able to remove particulate matter from the sand control pack 18. For this purpose, the gel plug 20 and sand control pack 18 are contacted with a hydrochloric acid solution of a concentration of from about 5 to about 28 volume percent which is utilized as a pre-flush. Thereafter, the gel plug and pack 18 are contacted with a mixture of hydrochloric and hydrofluoric acid in a concentration of about 12 percent hydrochloric acid to about 3 percent hydrofluoric acid which is sufficient to restore the pack permeability and remove particulate matter from said pack.
By utilization of this method, the particulate matter is removed from said gravel pack 18 without damaging said pack while increasing the permeability of the pack by the removal of said particulate matter. An added benefit of this method is that utilization of the solidifiable gel material enables the production of hydrocarbonaceous fluids to be resumed much earlier than heretofore possible.
In making the solidifiable gel material for utilization in this invention, a slurry is formed with 1,000 gallons of water. This slurry comprises about 40 pounds of base gel such as hydroxypropyl guar gum which forms a hydrate in the water. To this mixture is added about 600 pounds of hydroxypropyl guar gum which has been chemically treated to provide delayed hydration and thickening properties. Approximately 20 pounds of a buffer or catalyst suitable to obtain the desired pH and reaction time is added to said mixture. Cross-linking agents, such as borate and chromates, are then added in an amount of about 20 pounds. After forty to about forth-two pounds of sodium thiosulfate, an oxygen scavenger, is then added to the mixture. This gel mixture is pumped into the formation 10 near the productive interval. After solidification of the mixture and the lapse of the desired suspension time, the solidified gel plug 20 is removed by contacting said plug with hydrochloric acid of a concentration of 3 to about 28 volume percent. The amount of said acid should be sufficient to solubilize the gel composition in wellbore 12 and within said sand control pack 18.
A preferred mixture used to obtain the desired stability and rigidity, for example, is a mixture of hydropropyl guar gum crosslinked with transitional metals and ions thereof. The purpose of the transitional metal ions is to provide increased strength, stability, and rigidity for the subsequently formed solid gel material.
Hydropropyl guar gum is placed into the gel mixture in an amount from about 0.70 to about 10.0 weight percent of said mixture. As preferred, hydropropyl guar gum is placed in said mixture in about 7.2 percent by weight of said mixture.
Metallic ions which can be used in the pumpable gel mixture include titantium, zirconium, chromium, antimony, and aluminum. The concentration of these transitional metals in the pumpable fluid will of course vary depending upon the environmental nature of the wellbore and the formation. Although the exact amount of the metals required will vary depending on the particular application, it is anticipated that the metal should be included within the pumpable gel fluid in amounts of from about 0.005 weight percent to about 0.50 weight percent, preferably about 0.10 weight percent of said fluid.
Although the present invention has been described with preferred embodiments, it is to be understood that modifications and variations may be resorted to without departing from the spirit and scope of this invention, as those skilled in the art will readily understand. Such modifications and variations are considered to be within the purview and scope of the appended claims.
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A process for removing particulate matter from a non-dissoluble sand control pack containing grangulated ceramic material which pack is used to produce hydrocarbonaceous fluid from a subterranean formation. Said pack is contacted with a mineral acid of a strengh and composition sufficient to react with said particulate matter thereby removing said matter and increasing the permeability of said pack without damaging said pack.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a scan test system for a semiconductor device, for inspecting the short/open of a wiring connected between semiconductor devices.
[0003] 2. Description of the Prior Art
[0004] [0004]FIG. 5 is a schematic constitution diagram of a conventional scan test system for a semiconductor device shown, for instance, in JP-A-05/322989(1993). The semiconductor device of the system comprises a JTAG boundary scan register that can inspect the short/open of a wiring between the devices digital-connected. FIG. 5 shows a semiconductor device 2 , a digital input/output pin 6 , an internal system logic 8 , a JTAG specification boundary scan register or JTAG boundary scan register 9 , a boundary scan register chain 10 , TDO (Test Data Output) 11 , TMS (Test Mode Select) 12 , TDI (Test Data Input) 13 , TCK (Test Clock) 14 , and a TAPC (Test Access Port Controller) 15 .
[0005] [0005]FIG. 6 illustrates a basic constitution of the boundary scan register 9 . FIG. 6 shows an input multiplexer 16 , a shift register stage 17 , a parallel output stage 18 , data input 19 , Shift-DR (shift data register signal) 20 , Clock-DR (clock data register signal) 21 , Update-DR (update data register signal) 22 , and data output 23 .
[0006] The operation of the conventional scan test system for a semiconductor device will next be described.
[0007] The built-in boundary scan register 9 of each digital input/output pin 6 performs the basic operations of capture (Capture), shift (Shift), and update (Update) depending on the state transition of the TAPC 15 . This state transition of the TAPC 15 is done by an input to TMS, and the TAPC 15 gives a control signal necessary for the operation in each state.
[0008] These basic operations will next be described.
[0009] (1) Capture Operation
[0010] A value from a system circuit, that is, an internal system logic and an external system logic (herein, corresponding to the input from an analog sensor) is captured into the shift register stage 17 of the boundary scan register 9 .
[0011] (2) Shift Operation
[0012] The scan operation of a test data register is done. When the boundary scan register 9 is being specified by the present instruction, this test data register is connected between TDI 13 and TDO 11 , and a shift to the serial output direction is thereby caused by one bit synchronizing with TCK 14 .
[0013] (3) Update Operation
[0014] the parallel output stage 18 of the test data register is updated. When boundary scan register 9 is being specified by the present instruction, the data is transmitted from the shift register stage 17 of the boundary scan register 9 to the parallel output stage 18 synchronizing with TCK 14 . By the way, it is when Shift-DR 20 or Capture-DR becomes active that Clock-DR 21 becomes active.
[0015] The conventional scan test system for a semiconductor device is constituted as mentioned above. Therefore, because the conventional JTAG boundary scan register 9 is configured with a digital terminal, although it can detect the short/open of an wiring connected between digital-connected devices, it needs monitoring the wiring by additionally contacting the probes thereon in order to detect the short/open of an analog-connected wiring. However, there arises a problem that, with a recent trend of increase in the degree of integration of semiconductor devices, monitoring inspection by setting up probes has become more difficult.
[0016] Moreover, there arises a problem that, with a recent progress of increase in the pin number of semiconductor devices, the cost of monitoring inspection by setting up probes has become higher.
[0017] Herein, the reason why the conventional JTAG boundary scan register 9 shown in FIG. 5 cannot be connected to an analog terminal will be described. Since the built-in JTAG boundary scan register 9 of the semiconductor device 2 is constituted by a digital circuit, when the analog signal of a middle potential is input (for instance, 2.5 V at the digital input terminal of 5 V-interface), there arises a possibility that the increase of power consumption or a breakdown is caused because of the flow of a through current through the transistor in an input stage. Therefore, the JTAG boundary scan register 9 cannot be connected to the analog terminal.
SUMMARY OF THE INVENTION
[0018] The present invention has been accomplished to solve the above-mentioned problem, and is directed to a scan test system for a semiconductor device, by which in a semiconductor-mounted board obtained by mounting semiconductor devices thereon, the short/open of a wiring analog-connected between the devices can be inspected without probe-inspection.
[0019] First, the present invention provides a scan test system for a semiconductor device, comprising; a first semiconductor device comprising; a first analog input/output pin existing on the analog input side thereof; a first internal circuit; and a scan register connected therebetween; a second semiconductor device comprising; a second analog input/output pin on the analog input side thereof; a second internal circuit; and a scan register connected therebetween; and an analog wiring connecting the first analog input/output pin and the second analog input/output pin.
[0020] Herein, at least one of the first and the second semiconductor devices may constitute a register chain that serially connects a plurality of the scan registers within the device.
[0021] In addition, the scan register constituting the register chain may comply with the JTAG specification, and constitute a JTAG scan register, and the test system may comprise control means for controlling this JTAG scan register.
[0022] Second, the present invention provides a scan test system for a semiconductor device, comprising; a semiconductor device comprising; a digital/analog pin existing on the input side; a first scan register; an internal circuit; a second scan register; and a digital input/output pin existing on the output side, the first scan register being connected between the digital/analog double-functional pin and the internal circuit, and the second scan register being connected between the digital input/output pin and the internal circuit; a first register chain serially connecting a plurality of the first scan registers, each fetching the data input and outputting the result to the output side; a second register being connected to the first register chain and simultaneously serially connecting a plurality of the second scan registers, each fetching the data input and outputting the result to the output side; and switching means bypassing-at least one of the first and the second register chains and thereby connecting the data input to the output side.
[0023] Herein, the scan register constituting the first and the second register chains may comply with the JTAG specification, and constitute a JTAG scan register, and the test system may comprise control means for controlling this JTAG scan register.
[0024] In addition, the switching means may comprise a first switch, a first bypass line that bypasses the first register chain, a second switch and a second bypass line that bypasses the second register chain, the first switch switching between the first register chain and the first bypass line, and the second switch switching between the second register chain and the second bypass line.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] [0025]FIG. 1 is a schematic constitution diagram of the scan test system for a semiconductor device according to Embodiment 1 of the present invention;
[0026] [0026]FIG. 2 is a circuit diagram showing the basic constitution of the scan register;
[0027] [0027]FIG. 3 is a schematic constitution diagram of the scan test system for a semiconductor device according to Embodiment 2 of the present invention;
[0028] [0028]FIGS. 4A and 4B each are a schematic constitution diagram of the scan test system for a semiconductor device according to Embodiment 3 of the present invention;
[0029] [0029]FIG. 5 is a schematic constitution diagram of a conventional scan test system for a semiconductor device; and
[0030] [0030]FIG. 6 is a circuit diagram showing the basic constitution of a boundary scan register.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0031] An embodiment of the present invention will be described below.
[0032] Embodiment 1.
[0033] [0033]FIG. 1 is the schematic constitution diagram showing the scan test system for a semiconductor device according to Embodiment 1 of the present invention. FIG. 1 shows a semiconductor mounted board 1 such as printed circuit board, a semiconductor device 2 (first semiconductor device), an analog sensor 3 (second internal circuit, second semiconductor device), a scan register 4 , an analog input/output pin 5 , a digital input/output pin 6 , an analog wiring 7 , and an internal system logic 8 (first internal circuit).
[0034] By the way, the semiconductor mounted board 1 is widely used in all fields including general household electrical appliances, and an example of the analog sensor 3 include an acceleration sensor, an accelerator opening sensor, and a vehicle height sensor in the field of application for automobiles. These parts are usually constituted by a semiconductor device.
[0035] [0035]FIG. 1 shows the example of assembling the semiconductor device 2 and another semiconductor device containing the analog sensor 3 . However, a plurality of components are usually densely assembled on the board 1 . Thus, in Embodiment 1, it is intended that the analog wiring 7 is inspected in a digital mode by having the scan register 4 for each of the semiconductor device 2 and analog sensor 3 as a means of inspecting a complex wiring.
[0036] [0036]FIG. 2 shows the basic constitution of the scan register 4 . FIG. 2 shows a shift register stage 17 , a parallel output stage 18 , data input 19 , Clock-DR (clock data register signal) 21 , Update-DR (update data register signal) 22 , and data output 23 .
[0037] The operation of the scan test system for a semiconductor device according to Embodiment 1 will next be described.
[0038] A digital signal (“H” or “L”) is output by the scan register 4 on the side of analog sensor 3 from the analog input/output pin 5 to the semiconductor device 2 . On the other hand, on the side of the semiconductor device 2 , the scan register 4 takes the input digital signal (“H” or “L”) from the analog input/output pin 5 via the analog wiring 7 , and judges whether or not analog the wiring 7 is correctly connected. As a means to operate the scan register 4 , for instance, in the analog sensor 3 on the output side, external-pin setting detects the input level of a terminal for test, and makes the analog input/output pin 5 to output the digital signal (“H” or “L”). On the other hand, the scan register 4 on the input side is also made to take the data via a built-in CPU, and to output the data from another pin.
[0039] As mentioned above, according to Embodiment 1, only data setting in the scan register 4 can inspect in a digital mode the short/open of the analog wiring 7 analog-connected between the semiconductor device 2 and analog sensor 3 , and additionally thereby monitoring inspection such as contacting probes on each wiring which was conventionally done after assembling devices is not required. Therefore, the decrease in the inspection time and at the same time the decrease in the inspection cost can be realized. As a result, the effect that the inspection efficiency improves is achieved.
[0040] Embodiment 2.
[0041] [0041]FIG. 3 is the schematic constitution diagram showing the scan test system for a semiconductor device according to Embodiment 2 of the present invention. FIG. 3 shows a semiconductor mounted board 1 , a semiconductor device 2 (the first semiconductor device), an analog sensor 3 (the second semiconductor device), a scan register 4 , an analog input/output pin 5 , digital input/output pin 6 , an analog wiring 7 , an internal system logic 8 (the first internal circuit), a boundary scan register 9 (scan register), a boundary scan register chain 10 (register chain), TDO 11 (test data output pin), TMS 12 (test-mode-selecting pin), TDI 13 (test data input pin), TCK 14 (test clock pin), a TAPC 15 (test access port controller) (controlling means), and input/output pin 26 .
[0042] A supplementary explanation about these components will next be given. TCK 14 is a test clock input, i.e., a clock input that is a dedicated test logic that is common to each component, and that can operate a serial data path spreading across the components, differing from system clocks vary among the components. TMS 12 is a test mode select input. This signal is taken into the test logic on the rising edge of TCK 14 , is decoded by TAPC 15 , and controls the test operation. TDI 13 is a serial data input. This input value is taken into the instruction register that has been selected or the test data register that has been selected, on the rising edge of TCK 14 . TDO 11 is a serial data output. The content of the selected register is output to the outside via this TDO 11 on the rising edge of TCK 14 .
[0043] [0043]FIG. 3 shows the example of connecting semiconductor device 2 and analog sensor 3 as in the Embodiment 1. The boundary scan register 9 complies with JTAG specification, and constitutes the boundary scan register chain 10 by being serially connected. The dedicated TAPC 15 controls this boundary scan register specified by JTAG specification.
[0044] When the JTAG instruction is input to the TAPC 15 , the instrucited TAPC 15 t outputs the control signal to each boundary scan register 9 to be executed bya desired operation.
[0045] This TAPC 15 transitions to a variety of states ( 16 states in total) according to the signal changes of TMS 12 and TCK 14 . The outline of the transition state will be described hereinafter.
[0046] (1) Test-Logic-Reset: The state of resetting.
[0047] (2) Run-Test/Idle: The state of performing the test instruction.
[0048] (3) Select-DR-Scan: The temporary state for transitioning to other states.
[0049] (4) Select-IR-Scan: The temporary state for transitioning to other states.
[0050] (5) Capture-IR: The state of taking a fixed value into the shift register stage of the instruction register.
[0051] (6) Shift-IR: The stage of performing the scan operation of the instruction register.
[0052] (7) Exit 1-IR: The temporary state for transitioning to other states.
[0053] (8) Pause-IR: The state of temporarily stopping the shift operation of the instruction register.
[0054] (9) Exit 2-IR: The temporary state for transitioning to other states.
[0055] (10) Update-IR: The state of renewing the output latch of the instruction register.
[0056] (11) Capture-DR: The state of taking a value from the system circuit into the shift register stage of the test data register.
[0057] (12) Shift-DR: The stage of performing the scan operation of the test data register.
[0058] (13) Exit 1-DR: The temporary state for transitioning to other states.
[0059] (14) Pause-DR: The state of temporarily stopping the shift operation of the test data register.
[0060] (15) Exit 2-DR: The temporary state for transitioning to other states.
[0061] (16) Update-DR: The state of renewing the output latch of the data register.
[0062] The operation of the scan test system for a semiconductor device according to Embodiment 2 of the present invention will next be described.
[0063] A digital signal (“H” or “L”) is output by scan register 4 on the side of the analog sensor 3 from the analog input/output pin 5 to the semiconductor device 2 . On the other hand, on the side of the semiconductor device 2 , the boundary scan register 9 takes the input digital signal (“H” or “L”) and output the result from TDO 11 to the outside along the boundary scan register chain 10 . Because this boundary scan register 9 is specified by JTAG specification, the control thereof can be performed by automatically creating the test pattern by use of a commercial boundary scan register inspection apparatus. Inputting the predetermined signals from the outside to TMS 12 , TDI 13 , and TCK 14 makes TAPC 15 give rise to a state transition, and give a necessary control signal, to thereby operate the system.
[0064] As mentioned above, according to Embodiment 2, since the scan test system has a built-in JTAG boundary scan register, and comprises a register chain, in addition to a similar effect to the scan test system for a semiconductor device described in Embodiment 1, the system can use the test pattern automatically created by a commercial boundary scan register inspection apparatus, and thereby produces the effect that the inspection efficiency increases and the inspection cost decreases.
[0065] Embodiment 3.
[0066] [0066]FIG. 4A and FIG. 4B are the schematic constitution diagrams showing the scan test system for a semiconductor device according to Embodiment 3 of the present invention. The examples of installing a boundary scan register to a digital/analog-double-functional pin are shown. Shown in the figure are a semiconductor device 2 , a digital input/output pin 6 , an internal system logic 8 (internal circuit), a boundary scan register 9 (first and second scan registers), a boundary scan register chain 10 (first and second register chains), TDO 11 , TMS 12 , TDI 13 , TCK 14 , TAPC 15 , a digital/analog-double-functional pin 36 , and switches SW 1 and SW 2 (switching means, the first switch and the second switch).
[0067] Herein, since a commercial boundary scan inspection apparatus corresponds to a digital pin, when the digital/analog-double-functional pin 36 is used as an analog pin, the double-functional pin is used by means of switching the path by use of switches SW 1 and SW 2 . By the way, when the digital/analog-double-functional pin 36 is used as a digital pin, since the double-functional pin is used as the equivalent of a usual digital pin, the path is switched for avoiding a bypass.
[0068] [0068]FIG. 4A shows a case in which the digital/analog-double-functional pin 36 is used as a digital pin. In this case, since the double-functional pin is used as the equivalent of another dedicated digital pin, serially connecting the pin with the another boundary scan register enables a bulk inspection. On the other hand, FIG. 4B shows a case in which the digital/analog-double-functional pin 36 is used as an analog pin. In this case, the same operation as in Embodiment 2 is performed.
[0069] The operation of the scan test system for a semiconductor device according to Embodiment 3 of the present invention will next be described.
[0070] The boundary scan register 9 takes the digital signal (“H” or “L”) input in the semiconductor device 2 , and outputs the result from TDO 11 to the outside along boundary scan register chain 10 , to thereby perform the wiring inspection of the analog pin. By the way, the control of boundary scan register 9 is performed, as in the Embodiment 2, by making the TAPC 15 give rise to a state transition, and create a necessary control signal by means of inputting a signal from the outside to TMS 12 , TDI 13 , and TCK 14 .
[0071] As mentioned above, according to Embodiment 3, the same effect as that of Embodiment 2 is obtained, and additionally, the following effect is obtained. That is, since an optical scan register will be constituted based on JTAG instructions, when, for instance, a user uses a double-functional pin as a digital pin, the person can use the test pattern created by a commercial automatic test-pattern-creating tool, and carry out the bulk inspection, by constituting a chain by means of using the double-functional pin with another dedicated digital pin. Therefore, the effect that the inspection efficiency further improves is obtained.
[0072] As mentioned above, according to the present invention, since a scan test system for a semiconductor device comprises; a first semiconductor device comprising; a first analog input/output pin on the analog input side thereof; a first internal circuit; and a scan register connected therebetween; a second semiconductor device comprising; a second analog input/output pin on the analog input side thereof; a second internal circuit; and a scan register connected therebetween; and an analog wiring connecting the first analog input/output pin and the second analog input/output pin, in order to inspect in digital form the short/open of the wiring analog-connected between the first and the second semiconductor devices, the monitoring inspection such as contacting probes on each wiring which was conventionally done after assembling devices is not required. Therefore, the effect that the decrease in inspection cost can be performed and that the inspection efficiency improves is obtained.
[0073] According to the present invention, since at least one of the first and the second semiconductor devices constitutes a register chain that serially connects a plurality of the scan registers within the device, a commercial boundary scan register inspection apparatus can automatically create the test pattern. Therefore, in addition to the above-described effect, the effect that the inspection time and cost can be decreased is obtained.
[0074] According to the present invention, since the scan register constituting the register chain complies with the JTAG specification, and constitutes a JTAG scan register, and the test system comprises control means for controlling this JTAG scan register, the system can send the JTAG instruction to the control means, and the control means receiving the instruction outputs the control signal to each scan register, the system being able to perform the desired operation, to thereby automatically inspect the short/open of the wiring. As a result, the effect that the inspection time can be shortened, the extra monitoring inspection such as contacting the probe on each wiring can be eliminated, and the inspection efficiency simultaneously improves, is obtained.
[0075] According to the present invention, since a scan test system for a semiconductor device comprises; a semiconductor device comprising; a digital/analog pin existing on the input side; a first scan register; an internal circuit; a second scan register; and a digital input/output pin existing on the output side, the first scan register being connected between the digital/analog pin and the internal circuit, and the second scan register being connected between the digital input/output pin and the internal circuit; a first register chain serially connecting a plurality of the first scan registers, each fetching the data input and outputting the result to the output side; a second register being connected to the first register chain and simultaneously serially connecting a plurality of the second scan registers, each fetching the data input and outputting the result to the output side; and switching means bypassing at least one of the first and the second register chains and thereby connecting the data input to the output side, in addition to the above-described effect, when, for instance, a user uses a double-functional pin as a digital pin, the person can use an automatic test-pattern-creating tool by constituting the first and the second register chains by means of using the double-functional pin with another dedicated digital pin. On the other hand, when the person uses the double-functional pin as the analog pin, the person can constitute a scan register chain of only an analog pin. Therefore, the effect that the inspection can be carried out with efficiency is obtained.
[0076] According to the present invention, since the scan register constituting the first and the second register chains complies with the JTAG specification, and constitutes a JTAG scan register, and the test system comprises control means for controlling this JTAG scan register, the system can send the JTAG instruction to the control means, and the control means receiving the instruction outputs the control signal to each scan register, the system being able to perform the desired operation, to thereby automatically inspect the short/open of the wiring. As a result, the effect that the inspection time can be shortened, and additionally, that the inspection cost can decrease since the extra monitoring inspection such as contacting the probe on each wiring can be eliminated, is obtained. The effect that the inspection efficiency improves, is simultaneously obtained.
[0077] According to the present invention, since the switching means comprises: a first switch, a first bypass line that bypasses the first register chain, a second switch and a second bypass line that bypasses the second register chain, the first switch switching between the first register chain and the first bypass line, and the second switch switching between the second register chain and the second bypass line, the effect that the appropriate use of the first or the second switches enables the selection of the function, for instance, when the double-functional pin is used as both a digital pin and a analog pin, the use of the first switch can perform the switching, is obtained.
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There is provided a scan test system comprising: a semiconductor device including a scan register connected between an input/output pin on an analog input side and an internal system logic; a semiconductor device including a scan register connected between an input/output pin on an analog output side and an analog sensor; and an analog wiring connecting the input/output pins each other. Thus, the scan register can be chained to thereby constitute a boundary scan register chain, and thereby JTAG control can be carried out by use of TAPC. Therefore, monitoring inspection where probes are set up by means of high-density-assembling of semiconductor devices and the multiple pins of low-cost devices, can be achieved.
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BACKGROUND OF THE INVENTION
The present invention is directed to a vibratory compactor used, for example, to compact backfilled trenches after a pipeline is laid or to compact the floor of a trench or to compact asphalt or larger areas, and more particularly, relates to steering for a vibratory compactor of the above-mentioned type.
Vibratory compactors are used in a variety of ground compaction and ground leveling applications. Most vibratory compactors have plates or rollers that rest on the surface to be compacted and that are excited to vibrate so as to compact and level a worked surface. A common vibratory compactor, and one to which the invention is well-suited, is a vibratory trench roller.
The typical vibratory trench roller includes a chassis supported on the surface to be compacted by front and rear rotating drum assemblies. Each drum assembly supports a respective subframe of the chassis if the trench roller is an articulated trench roller. The subframes may be articulated to one another by a pivot connection. Each of the drum assemblies may include a stationary axle housing and a drum that is mounted on the axle housing and that is driven to rotate by a dedicated hydraulic motor. Hydraulic motors are typically supplied with pressurized hydraulic fluid from a pump which may be powered by an engine mounted on one of the subframes.
Each drum may be excited to vibrate by a dedicated exciter assembly that is located within the associated subframe and is powered by a motor connected to a pump. The exciter assembly typically comprises one or more eccentric masses mounted on a rotatable shaft positioned within the subframe. Rotation of the eccentric shaft imparts vibrations to the subframe and to the remainder of the drum assembly. The entire machine may be configured to be as narrow as possible so as to permit the machine to fit within a trench whose floor is to be compacted. Machine widths of less than 3 feet (1 meter) are common. Vibratory trench rollers of this basic type are disclosed, e.g., in U.S. Pat. No. 4,732,507 to Artzberger; U.S. Pat. No. 4,793,735 to Paukert; U.S. Pat. No. 5,082,396 to Polacek; U.S. Pat. No. 7,059,802 to Geier et al.; and U.S. Pat. No. 8,585,317 to Sina, the entireties of which are hereby expressly incorporated by reference thereto.
Vibratory roller machines with articulated steering are advantageous in that their movement permits changes in direction during normal travel, or small corrections in direction, to be rapidly undertaken without damaging the already compacted surface of the ground. To effect such changes in direction, the typical articulated steering system employs an extensible linear steering actuator mounted between the subframes and a solid axle configuration connecting left and right drum halves. A hydraulic cylinder is employed in most instances. Steering is affected by linearly extending or retracting the steering actuator to cause the front subframe to pivot about the machine's longitudinal centerline and alter the articulation angle between the front and rear subframes.
However, high pressure steering actuators are costly and are prone to failure, such as by way of oil leaks and/or pressure losses. Electrically powered high force actuators suitable for steering are available, but are more costly than hydraulic actuators. And they have many moving parts which are prone to failure in severe operating conditions. Also, solid axle configurations may impede steering function and precision and may cause the drums to scratch and/or deform finished surfaces when steering to the left or right. In addition, vibratory roller machines with linear steering actuators and solid axle configuration are further limited by the maximum slope in which they can traverse. The need therefore exists to provide a system for a vibratory roller machine that eliminates one or more of the foregoing disadvantages.
SUMMARY OF THE INVENTION
The present invention provides an improved steering system for an articulated vibratory roller machine. Improved steering can be accomplished without necessarily using a dedicated steering actuator. Instead, steering angles may be altered by driving left and right side drums or drum halves at the front and rear ends of the roller at different rotational speeds and/or directions. This differential action, coupled with independent control of the front and rear drum assemblies, creates the desired steering angle by pivoting the front and back sections of the machine about a central articulated joint. As a result, a cost-effective solution that eliminates the need for conventional steering components and their associated disadvantages is provided.
In embodiments, independent drive motors, which may be electrically or hydraulically driven, may be used to drive four roller drums, independently. Independent control of each drum provides more precise steering control, better directional control on slopes, and less scuffing of finished surfaces when turning.
With electrically-driven motors, the possibility of oil leaks and/or pressure losses in the machine may be even further reduced or eliminated entirely. Alternatively, the individual motors could be hydraulically driven.
An electronic control system with operator inputs and/or sensors may be used to determine the motor speeds needed to move and steer the machine. Various sensors may be used to determine one or more of tilt angles (roll, yaw, pitch), angular motion rates, acceleration levels, machine position, drum speeds and the articulated joint angle for the machine. The control system may be used to control the speed of each of the drums independently according to operator inputs, machine sensors, and a control program. Independent rotational control of each drum creates the desired steering angles and also provides more precise steering control, better directional control on slopes, and less scuffing of finished surfaces when turning.
If desired, the control system can provide semi-autonomous control of the movement of the machine. Semi-autonomous control can be utilized, for example, to maintain the machine operator's commanded speed and direction. The machine control may perform semi-autonomous control by quickly reacting to deviations from the commanded machine travel direction and position, and controlling the roller drum speeds to correct for the detected travel deviations. For example if the operator is commanding forward travel at low speed while compaction the soil, the control system can utilize sensor feedback to adjust the speed of one or more of the drums to maintain the commanded machine vector direction and speed until the operator changes the input. This control is useful to compensate for variations in soils and surface conditions. Another application of semi-autonomous control is detecting and avoiding collisions.
Various sensors such as radar, sonar and lidar can be added to the control system to sense objects and detect the shape of the worksite. The control system can use these sensors to detect travel deviations as discussed above. The control system also can use these sensors to detect objects in the machine's path, trench walls or other physical objects. The control system can react to these signals to control the machine (such as automatically stopping or turning) so as to prevent a collision and avert damage to the worksite or machine, and can also improve operational safety.
If desired, the control system can also provide fully autonomous control of the machine movements. For example, soil compaction often requires multiple passes to achieve the desired soil density. The control system can be configured to “learn” the travel path (or the worksite shape) in the area of the worksite where soil compaction is required. In one example, during the first pass of soil compaction the control system learns the travel path by progressively calculating and recording the true position of the machine and/or the position of the machine relative to a known reference. This learning is done by continuously monitoring the control system sensors, applying algorithms to determine the travel locations, and then storing the location data in the electronic control system memory. (If soil compaction is required over a larger area, the operator could simply drive the machine around the outer edges of the area.) After this location data is stored in the control system, the controls can be programmed to make additional passes over the same path, (or over the entire worksite shape) to ultimately compact the soil to the required soil density. Since multiple passes are typically required to fully compact a surface, this system can improve compaction quality, reduce operator workload, and improve efficiency of the compaction process.
Another way to use autonomous control would be to program a machine to drive the length of a trench and employ sensor feedback to automatically keep the machine centered between the walls of the trench. This control can improve efficiency by preventing the roller drums from coming into contact with the trench sides. When the machine reaches the end of a trench, it can automatically stop and/or reverse and then follow the original path to further compact the soil.
Yet another way to use autonomous control would be to program one or more machine(s) to be a slave to a master machine. The slave machine(s) could follow the travel path and speed of the master machine. Using this technique, multiple trench rollers could be operated by a single person, thereby improving the compaction speed and efficiency.
Instead of employing four separate drive motors, only two drive motors could be provided for the respective front and rear subframes. Each drive motor may then be connected to the associated drum assembly by a differential. Individual control of the drums may be effected using brakes. Instead of, or alternatively to, using brakes for individual drum control, differential speed control of the drums of each drum assembly may be achieved through control of a controllable limited slip differential.
In accordance with aspects of the invention, a vibratory roller machine may comprise a chassis comprising a front subframe and a rear subframe coupled together at a pivot connection. A front drum assembly may be rotatably mounted to the front subframe, and a rear drum assembly may be rotatably mounted to the rear subframe. Each drum assembly includes left and right drums. A position sensor may detect a relative angular displacement between the front subframe and the rear subframe and generate a relative position value, and a controller may be configured to receive the relative position value for individually adjusting the rotation of any one or more of the drums to control movement and steering of the vibratory roller machine.
The position sensor may comprise a first gyroscope located on the front subframe and a second gyroscope located on the rear subframe, a linear steer angle sensor between the front subframe and the rear subframe, an angular position sensor located at the pivot connection, and/or other sensor(s). A calibration device or algorithm may be used to calibrate the position sensor, and may include a global positioning system.
Another aspect of the invention may provide a method for steering a vibratory roller machine. The method may comprise (a) pivotally coupling a front subframe and a rear subframe together, the front and rear subframe having respective front and rear drum assemblies, each drum assembly having left and right drums rotatably mounted to the associated subframe; (b) commanding the vibratory roller machine to move in a direction; and (b) controlling the rotation of the drums on the front and rear of the machine relative to one another and independently of the rotation of the drums on the other end of the machine to provide the commanded movement and steering.
The method may also comprise generating a relative position value indicating a relative position difference between the front subframe and the rear subframe and individually adjusting the rotation of the one or more drums based on the generated relative position value.
The vibratory roller machine may be a ride-on machine or a walk-behind machine that is remotely controlled by an operator using a remote control device.
These and other features and advantages of the invention will become apparent to those skilled in the art from the following detailed description and the accompanying drawings. It should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the present invention, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifications.
BRIEF DESCRIPTION OF THE DRAWINGS
Preferred exemplary embodiments of the invention are illustrated in the accompanying drawings in which like reference numerals represent like parts throughout, and in which:
FIG. 1 is a partially cut away side elevation view of an exemplary vibratory roller machine comprising a steering system according to an embodiment of the present invention;
FIG. 2 is a schematic top plan view of the vibratory roller machine of FIG. 1 ;
FIG. 3 is a schematic diagram of an electric drive and control system for the vibratory roller machine of FIGS. 1 and 2 ;
FIG. 4 is a schematic top plan view of a vibratory roller machine according to another embodiment of the present invention; and
FIG. 5 is a schematic diagram of a hydraulic drive system for a vibratory roller machine according to another embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings, and initially to FIG. 1 , an exemplary vibratory roller machine 10 is illustrated in accordance with an embodiment of the present invention. The machine 10 is a so-called walk-behind trench roller comprising a self-propelled machine supported on the ground via a front rotating drum assembly 12 and a rear rotating drum assembly 14 . The machine 10 comprises an articulated chassis having front and rear subframes 16 and 18 , respectively, connected to one another via a pivot connection 20 . In an embodiment, the chassis may have a narrow width, such as about 20 inches (50 cm) wide, to permit the machine 10 to be used to compact the bottom of trenches for laying pipeline and the like.
The front subframe 16 may support an engine 22 accessible via a ventilated hood 24 . The engine 22 supplies motive power to a generator 26 that generates power used to drive the powered components of the machine 10 . The engine 22 and generator 26 may form part of a series hybrid drive system. A radiator 28 may also be provided for cooling the engine 22 . The machine 10 can be lifted for transport or deposited in a trench whose floor is to be compacted by connecting a chain or cable to a lift eye 30 located, at the rear of the front subframe 16 .
The front and rear rotating drum assemblies 12 and 14 may be mirror images of one another, though not necessarily. One difference between the drum assemblies could be, for example, that a drive motor for the exciter assembly of the front drum assembly 12 may be mounted in an associated axle housing from the right side of the machine 10 , and a drive motor for the exciter assembly for the rear drum assembly 14 may be mounted in an associated axle housing from the left side of the machine 10 .
As is generally understood in the art, each of the front and rear drum assemblies 12 and 14 may be excited to vibrate by a dedicated exciter assembly (not shown) that is powered by a drive system. The exciter assembly typically comprises one or more eccentric masses (not shown) mounted on a rotatable shaft(s) (not shown) positioned within an axle housing. Rotation of the eccentric masses imparts vibrations to the axle housing and, in turn, to the remainder the drum assembly. In this way, the front and rear (rotating) drum assemblies 12 and 14 are operable to compact the ground as is generally understood.
The outer surface of each of the front and rear rotating drum assemblies 12 and 14 could be smooth, but in the machine 10 is provided with a so-called sheep's foot surface in the illustrated embodiment so as to have compaction lugs or sheep's feet formed thereon. Each of the drum assemblies 12 and 14 may also extend laterally by an amount that determines the compaction width of the machine 10 . For example, in the illustrated embodiment in which the machine 10 is configured to compact a 32″ (82 cm) wide strip, each of the drum assemblies may extend beyond the associated subframe by several inches. In an application in which the machine 10 is configured to compact a 22″ (56 cm) wide strip, each of the drum assemblies may be generally flush with the associated sub frame.
The rear subframe 18 may support a control system for the machine as well as an enclosed storage compartment accessible via a pivotable cover (not shown). These controls may include a remote control receiver or transmitter/receiver 34 ( FIG. 3 ) mounted on the machine for sending and/or receiving signals to a remote control device, such as an infrared sensor. Accordingly, the transmitter/receiver 34 may permit remotely receiving motion commands and/or system information, such as firmware updates, for the machine 10 , and/or remotely sending diagnostic and/or system information specific to the machine 10 back to the remote control device.
Each drum of each of the drum assemblies 12 and 14 may also have an internal flange 36 having a central aperture 38 for receiving an axle support hub 40 . The axles not shown may be driven to rotate by a driven gear (not shown) that is mounted directly on the axle 42 and that may be driven by a series hybrid drive system 50 . The series hybrid drive system 50 includes the aforementioned engine 22 and generator 26 , as well as a fuel tank 54 and a power storage system 58 . The power storage system 58 of this embodiment comprises a battery bank comprising one or more batteries housed within the rear subframe 18 that are in communication with the engine 22 and the generator 26 . Depending on the power requirements of a particular machine, the battery bank could be supplemented by or even replaced by a capacitance bank. Operation of and power transfer between the engine 22 , the generator 26 , the power storage system 58 and the powered components of the machine 10 are controlled by a controller 56 .
Referring now to the schematic top plan view of FIG. 2 , the front drum assembly 12 includes first and second (i.e., left and right) drum sections 12 a and 12 b , or simply “drums,” and the rear drum assembly 14 similarly has first and second (i.e., left and right) rear drums 14 a and 14 b . The first and second front drums 12 a and 12 b are rotatably mounted to the front subframe 16 via a front support mechanism 60 , and the first and second rear drums 14 a and 14 b are rotatably mounted to the rear subframe 18 via a rear support mechanism 62 . All four drums may be fixed from pivotal movement with respect to the associated subframe, but it is conceivable that a range of pivoting could be accommodated for even more versatile steering control. The first and second front drums 12 a and 12 b and the first and second rear drums 14 a and 14 b furthermore may be driven individually via corresponding first and second front drive motors 64 a and 64 b and first and second rear drive motors 66 a and 66 b , respectively. The first and second front drive motors 64 a and 64 b and the first and second rear drive motors 66 a and 66 b may be electrical motors.
A single parking brake may be provided for one or more of the drum assemblies. Instead or in addition to such a parking brake, the front drums 12 a and 12 b and rear drums 14 a and 14 b may each also be provided with corresponding first and second front brakes 70 a and 70 b and first and second rear brakes 72 a and 72 b , respectively, as shown in FIG. 2 . In addition, front and rear vibration exciter motors 74 and 76 may be accommodated in the front and rear support mechanisms 60 and 62 , respectively, for driving the front and rear exciter assemblies. The front and rear support mechanisms 60 and 62 may be, in turn, connected to the front and rear subframes 16 and 18 , respectively, such that that the front and rear support mechanisms 60 and 62 are vibrationally damped.
The machine 10 further includes sensor(s) for enabling multiple capabilities, including eliminating the need for conventional steering components and their associated disadvantages. Among the sensors, the machine 10 includes a position sensor for detecting a relative angular position difference between the front subframe 16 and the rear subframe 18 and generating a relative position value. This position value can be used by the controller to determine a steering angle with accuracy within a couple of degrees. When an operator provides a steering commands, the controller 56 , receiving input from the position sensor, independently drives the left and right side drum halves at each end of the machine at different speeds to realize the commands.
The position sensor may comprise a first gyroscope 80 located on the front subframe 16 and a second gyroscope 82 located on the rear subframe 18 . The first gyroscope 80 may sense three dimensional spatial changes in position with respect to the front subframe 16 and the second gyroscope 82 may sense three dimensional spatial changes in position with respect to the rear subframe 18 . Accordingly, a relative position difference between the first and second gyroscopes 80 and 82 may be detected, and a corresponding relative angular position value may be generated by the controller 56 . The first and second gyroscopes 80 and 82 may be Micro Electro-Mechanical System (MEMS) gyroscopes, Fiber Optic Gyroscopes (FOG), or any other gyroscope type providing similar functionality.
Instead of or in addition to the gyroscopes 80 and 82 , the position sensor may comprise an angular position sensor 84 located at the pivot connection 20 . The angular position sensor 84 may monitor a relative angular position between the front subframe 16 and the rear subframe 18 . Accordingly, a corresponding relative angular position value may be generated by the controller 56 .
In yet another configuration, the aforementioned sensors may be supplemented or replaced in whole or in part by a linear steering angle sensor 86 located between the front subframe 16 and the rear subframe 18 . The linear steer angle sensor 86 may sense a relative position difference between the front subframe 16 and the rear subframe 18 , such as by detecting a change in the distance between the front subframe 16 and the rear sub frame 18 . Accordingly, a corresponding relative position value may be generated and sent to the controller 56 .
The linear steer angle sensor 86 could be, for example, an optical sensor in which light is transmitted from a point on one subframe and received by a point on the other subframe. The light transmission may the monitored and timed to detect a change in the distance between the front subframe 16 and rear subframe 18 . The linear steer angle sensor 86 could also be, for example, a retractable rod connected between the front subframe 16 and the rear subframe 18 as seen in FIG. 1 . Motion between the front subframe 16 and the rear subframe 18 would cause the rod the retract or expand, permitting a change in the distance between the front subframe 16 and the rear subframe 18 to be detected by detecting a change in rod length. The linear steer angle sensor 86 could also be implemented as a magnetic sensor, such as a Hall Effect sensor in which the proximal strength of a magnetic field is determined with a resulting current flow, or by any other suitable mechanism, without detracting from the scope of the invention.
The machine 10 may also include a location sensor 88 , such as a Global Positioning System (GPS), for precisely determining the location of the machine 10 . The location sensor 88 may operate, alone, or in cooperation with front and rear magnetometers 90 and 92 located on the front and rear subframes 16 and 18 , respectively, to provide direction and bearing information, such as in the form of a compass, to the controller 56 .
The location sensor 88 may serve as a calibration sensor for calibrating the position sensors 80 , 82 , 84 , and/or 86 to null any errors which otherwise may accumulate. For example, the location sensor 88 could transmit an actual position signal to the controller 56 . That signal could then be compared to another signal based on the data from the sensor(s) 82 , 84 , and/or 86 to determine if the difference exceeds a threshold, which may be an actual quantified value or a percentage value. The controller 56 , in turn, and potentially in conjunction with an integrated timer, may periodically calibrate the position sensor(s), such as reinitializing the first and second gyroscopes 80 and 82 , or the angular position sensor 84 , or the linear steer angle sensor 86 , to remove accumulated error.
The machine 10 may also include a tipping sensor 94 for detecting an inclination of the machine, relative to the horizontal, beyond which the machine is in danger of tipping. The tipping sensor may be, for example, an accelerometer or a gyroscope which may also be connected to the controller 56 . The controller can also use these sensors to determine the position and speed of the machine.
As described above, the controller 56 can use signals from these and/or other sensors, such as such as radar, sonar and lidar, to control the drums to effect autonomous or semi-autonomous control of the machine.
It will be appreciated that one or more of the aforementioned sensors may be used in various combinations to achieve various embodiments of the present invention without departing from the spirit thereof.
Referring now to FIG. 3 , a schematic diagram of an electric drive and control system 100 for the vibratory roller machine of FIGS. 1 and 2 is provided. Powered components of the machine 10 , including the exciter assemblies and drive assemblies of the drum assemblies 12 and 14 , may be driven by the engine 22 .
The electric drive and control system 100 may be a series hybrid drive system as described above with respect to FIG. 1 and U.S. Pat. No. 8,585,317 to Sina, the entirety of which is hereby expressly incorporated by reference. The electric drive and control system 100 may include the aforementioned engine 22 , generator 26 , power storage system 58 and a starter 104 . Operation of and power transfer between the engine 22 , the generator 26 and the power storage system 58 , and the powered components of the machine 10 , including the first and second front drive motors 64 a and 64 b , the first and second rear drive motors 66 a and 66 b , the first and second front brakes 70 a and 70 b , the first and second rear brakes 72 a and 72 b , and the front and rear vibration exciters 74 and 76 , are controlled by the controller 56 .
The transmitter/receiver 34 may receive motion commands, which may then be decoded or otherwise conditioned by a decoder 102 , and which are sent to the controller 56 . The controller 56 also communicates with a sensor array 106 which may include some or all of the various sensors of the machine 10 , including the first and second gyroscopes 80 and 82 , the angular position sensor 84 , the linear steer angle sensor 86 , the location sensor 88 , the front and rear magnetometers 90 and 92 , the tipping sensor 94 , and/or other sensors.
The controller 56 , receiving a motion command from the transmitter/receiver 34 , and receiving a relative position value via the sensor array 106 , may individually adjust the rotation of any one or more of the first and second front drums 12 a and 12 b and the first and second rear drums 14 a and 14 b to provide movement and steering for the machine 10 . In particular, the controller 56 may individually adjust one or more of the first front drive motor 64 a , the second front drive motor 64 b , the first rear drive motor 66 a , and the second rear drive motor 66 b . In other words, the controller 56 may individually adjust the rotation of each of the drums through control of its respective drive motor.
Table 1 below provides a mapping by which a motion command, or “commanded roller movement,” may be implemented by the controller 56 individually adjusting the rotation of the drums through adjusting one or more of their respective drive motors.
TABLE 1
Commanded Roller Movement vs. Motor Traction Drive Function.
Commanded
Motor
Motor
Motor
Motor
Roller
64a (Left
64b (Right
66a (Left
66b (Right
Movement
Front)
Front)
Rear)
Rear)
1.
Forward
F
F
F
F
2.
Reverse
R
R
R
R
3.
Forward, Right
Fast F
Slow F
Slow F
Fast F
Turn-initiate
4.
Forward, Right
Fast F
Slow F
Fast F
Slow F
Turn-maintain
5.
Forward, Left
Slow F
Fast F
Fast F
Slow F
Turn-initiate
6.
Forward, Left
Slow F
Fast. F
Slow F
Fast F
Turn-maintain
7.
Reverse, Right
Slow R
Fast R
Fast R
Slow R
Turn-initiate
8.
Reverse, Right
Fast R
Slow R
Fast R
Slow R
Turn-maintain
9.
Reverse, Left
Fast R
Slow R
Slow R.
Fast R
Turn-initiate
10
Reverse, Left
Slow R
Fast R
Slow R
Fast R
Turn-maintain
11.
Stationary
F
R
R
F
Articulation
Right
12.
Stationary
R
F
F
R
Articulation
Left
An operator may provide the commands in Table 1 with a remote control device, which may include command entry elements such as a first joystick for forward and reverse movement commands and a second joystick for left and right steering commands. A fast forward travel speed (“Fast F”) and/or a fast reverse travel speed (“Fast R”) could typically be about 1.50 miles per hour, or 2.5 kilometers per hour. A slow forward travel speed (“Slow F”) and/or a slow reverse travel speed (“Slow R”) could typically be about 0.75 miles per hour, or 1.3 kilometers per hour.
As shown in Table 1, upon receiving a command to turn the machine 10 in a given direction, the controller 56 may control the motors in a first manner to initiate a turn and a second manner to maintain that turn once the commanded articulation angle is achieved. For example, when the machine 10 is moving forward and is commanded to turn to the right, the motors 64 a and 66 b for left front drum 12 a and right rear drum 14 b are driven relatively fast, and the motors 64 b and 66 a for right front drum 12 b and left rear drum 14 b are driven relatively slowly. This results in a speed differential between not only the left and right drums on each end of the machine 10 , but also between the front and rear drums on each side of the machine. See Row 3 in Table 1. Then, to maintain the turn at a designated, and possibly user-defined, angle, the speed differential of the rear drums is reversed such that the left rear drum 14 a is now driven at higher speed than the right rear drum 14 b . See Row 4 in table 1. Since the angle between the front and rear subframes 16 and 18 of the machine 10 is no longer changing, scrubbing, scratching, or other marring of the surface being compacted or otherwise traversed is prevented by preventing the drums from sliding over the surface. This effect cannot be reliably achieved with systems steered by conventional linear actuators or even with so called “panzer” type steering systems in which both drums on a given side of the machine are driven at a first speed and both drums on the opposite sides of the machine are driven at a second speed that is different from the first speed. Indeed, scrubbing is reduced even during turn initiation because the shorter drums on the left and right sides of the machine slide over a shorter arc than traditional machines with a single drum extending the width of each section of the machine. The same strategy, adapted appropriately for the desired turn direction and the current direction of travel, can be used to effect a left turn of a forward traveling machine or a left or right turn of a machine traveling in reverse. See Rows 5-10 in Table 1.
Another ramification of the full differential steering made possible by the invention is to articulate the front subframe 16 of a stationary machine 10 left or right by driving all drums at the same or possibly different speeds with the drums at opposite corners and opposite sides of the machine being driven in opposite directions. Hence, in one example, the motors 64 a and 66 b for the drums 12 a and 14 b are driven in the forward direction and the motors 64 b and 66 a for the drums 12 b and 14 a are driven in the reverse direction. See Rows 11 and 12 in Table 1. Turning a stationary machine 10 is useful, for example, when a trench roller encounters a corner or a “Y” in the trench and a greater steering angle is required than can be obtained by differential steering of a moving machine alone.
Still another capability of a system having the ability to provide independent four drum control is to provide better steering control when the machine traverses up or down a slope, in which case the machine's center of gravity moves toward the downhill side of the slope. In this situation, the two drums on the uphill side have a relatively low downforce since the majority of the machine's weight is supported by the two downhill drums. The uphill drums therefore cannot provide robust steering control since they would tend to slip on the soil. A similar traction differential occurs on opposite sides of the machine 10 when the machine traverses a side slope. Differential traction also may occur during travel on level ground, such as when the drums on one side of the machine are supported on solid soil, and the drums on the other side of the machine are supported on loose soil such as sand. In any of these scenarios, the inventive individual control of the drums permits steering control to be concentrated on the drums having better traction.
Hence, with four-drum independent control, the downhill/higher-traction drums can be rotated at different rates, or in opposite rotational directions, until the desired travel direction or articulation angle is achieved.
Independent four drum speed control can also be used to more reliably maintain travel of the machine along a commanded or other desired course. For example, in the simplest case of a commanded straight-ahead travel, the above-described sensors can be used by the controller 56 to detect any deviation from straight-line travel and used as open or closed-loop feedback control of the motors 64 a , 64 b , 76 a , and/or 66 b to effect a slight turn that returns the machine 10 to the straight line. A desired travel direction can be maintained in a traditional articulated roller only by locking the steering cylinder in an appropriate position.
The disclosed system also has the advantage of eliminating the hydraulic steering actuator and the attendant expense and risk of leaks. Additional configurations are provided for moving straight forward and straight in reverse, as well as stationary articulated turning, left or right, to make sharp changes in direction practically on the spot.
Other mechanisms can be used to effect independent speed control of the halves of the front and rear drum assemblies of an articulated roller within the scope of the present invention.
For example, referring now to FIG. 4 , the first and second front drums 212 a and 212 b and the first and second rear drums 214 a and 214 b may each be driven via single associated front and rear drive motors 264 and 266 , respectively. The front drive motor 264 is coupled to both of the associated drums 212 a and 212 b via a differential 265 , and the rear drive motor 266 is coupled to both rear drums 214 a , 214 b via an open or limited slip differential. In this case, the speeds of the opposed drums 212 a and 212 b or 214 a and 214 b on a given end of the machine can be controlled by individual control of the brakes 270 a , 270 b , 272 a and 272 b . This control can be performed by a controller under manual input and under feedback from the various sensors generally as described above. Instead of, or in addition to, controlling drum rotation through operation of the brakes, differential speed control of one or both of the front and rear drum assemblies can be implemented through controlling a controllable limited slip differential serving as an associated drum assembly's differential. All other components of the machine 210 of FIG. 4 are the same as the corresponding components of the machine 10 of FIGS. 1-3 and are designated by the same reference numeral, incremented by 200 . A description of these components is omitted for the sake of conciseness.
The individual drums also could be driven and controlled hydraulically rather than electronically. For example, referring to the schematic diagram of FIG. 5 , in one embodiment, left and right front drums 312 a and 312 b are driven by left and right variable output hydraulic drive motors 364 a and 364 b , and, left and rear drums 314 a and 314 b are driven by left and right variable output hydraulic drive motors 366 a and 366 b , respectively. All motors are driven by a master pump 380 receiving hydraulic fluid from a reservoir 382 and powered by an engine 322 .
A variable position solenoid valve 384 controlling the master pump 380 , as well as all four hydraulic motors 364 a , 364 b , 366 a , and 366 b , are controlled by a controller 356 under operator input and under feedback from a sensor array 406 . This control can occur generally as discussed above in connection with the first embodiment and potentially using some or all of the same sensors described above in connection with the first embodiment, to achieve the independent speed control of all four drums. Likewise, brakes (not shown) may again be used in this embodiment.
Although the best mode contemplated by the inventors of carrying out the present invention is disclosed above, practice of the above invention is not limited thereto. It will be manifest that various additions, modifications and rearrangements of the features of the present invention may be made without deviating from the spirit and the scope of the underlying inventive concept
It should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure. Nothing in this application is considered critical or essential to the present invention unless explicitly indicated as being “critical” or “essential.”
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Apparatus and method provides for an improved steering system for an articulated vibratory roller machine. Steering can be accomplished without the use of a dedicated steering actuator. Instead, steering angles may be created by independently driving left and right side drum halves at the front and rear ends of the machine at different speeds and/or directions. This differential action creates the desired steering angle by rotating the front and back halves of the machine about a central articulated joint. As a result, a cost-effective and versatile solution that eliminates the need for conventional steering components and their associated disadvantages is provided.
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This is a continuation of application Ser. No. 07/654,852 filed Feb. 13, 1991, now abandoned, which is a division of 07/260,839 filed Oct. 21, 1988 and issued as U.S. Pat. No. 4,997,821.
FIELD OF THE INVENTION
This invention is in the field of clinical neurology and relates specifically to a class of compounds, compositions and methods for neuro-protective purposes such as controlling chronic or acute neurotoxic injury or brain damage resulting from neuro-degenerative diseases. For example, these compounds are particularly useful for treating neurotoxic injury which follows periods of anoxia or ischemia associated with stroke, cardiac arrest or perinatal asphyxia. The compounds would also be useful as anti-convulsants and analgesics.
BACKGROUND OF THE INVENTION
Unlike other tissues which can survive extended periods of hypoxia, brain tissue is particularly sensitive to deprivation of oxygen or energy. Permanent damage to neurons can occur during brief periods of hypoxia, anoxia or ischemia. Neurotoxic injury is known to be caused or accelerated by certain excitatory amino acids (EAA) found naturally in the central nervous system (CNS). Glutamate (Glu) is an endogenous amino acid which has been characterized as a fast excitatory transmitter in the mammalian brain. Glutamate is also known as a powerful neurotoxin capable of killing CNS neurons under certain pathological conditions which accompany stroke and cardiac arrest. Normal glutamate concentrations are maintained within brain tissue by energy-consuming transport systems. Under low energy conditions which occur during conditions of hypoglycemia, hypoxia or ischemia, cells can release glutamate. Under such low energy conditions the cell is not able to take glutamate back into the cell. Initial glutamate release stimulates further release of glutamate which results in an extracellular glutamate accumulation and a cascade of neurotoxic injury.
It has been shown that the sensitivity of central neurons to hypoxia and ischemia can be reduced by either blockage of synaptic transmission or by specific antagonism of postsynaptic glutamate receptors [see S. M. Rothman and J. W. Olney, "Glutamate and the Pathophysiology of Hypoxia--Ischemic Brain Damage", Annals of Neurology, Vol. 19, No. 2 (1986)]. Glutamate is characterized as a broad spectrum agonist having activity at three neuronal excitatory amino acid receptor sites. These receptor sites are named after the amino acids which selectively excite them, namely: Kainate (KA), N-methyl-D-aspartate (NMDA or NMA) and quisqualate (QUIS). Glutamate is believed to be a mixed agonist capable of binding to and exciting all three receptor types.
Neurons which have EAA receptors on their dendritic or somal surfaces undergo acute excitotoxic degeneration when these receptors are excessively activated by glutamate. Thus, agents which selectively block or antagonize the action of glutamate at the EAA synaptic receptors of central neurons can prevent neurotoxic injury associated with anoxia, hypoxia or ischemia caused by stroke, cardiac arrest or perinatal asphyxia.
Aminophosphonic acids have been investigated as neurotransmitter blockers [see M. N. Perkins et al, Neuroscience Lett., 23, 333 (1981); and J. Davies et al, Neuroscience Lett., 21, 77 (1981)]. In particular, compounds such as 2-amino-4-(2-phosphonomethylphenyl)butyric acid and 2-(2-amino-2-carboxy)ethylphenylphosphonic acid have been synthesized for evaluation as antagonists in blocking the action of the neurotransmitter compounds L-glutamic acid and L-aspartic acid [K. Matoba et al, "Structural Modification of Bioactive Compounds II. Syntheses of Aminophosphonic Acids", Chem. Pharm. Bull., 32, (10) 3918-3925 (1984)].
U.S. Pat. No. 4,657,899 to Rzeszotarski et al describes a class of ω-[2-(phosphonoalkylenyl)phenyl]-2-aminoalkanoic acids characterized as being selective excitatory amino acid neurotransmitter receptor blockers. These compounds are mentioned for use as anticonvulsants, antiepileptics, analgesics and cognition enhancers. Typical compounds of the class include 3-[2-phosphonomethylphenyl]-2-aminopropanoic acid and 3-[2-(2-phosphonoethyl)phenyl]-2-aminopropanoic acid. European Patent Application 203,891 of Hutchison et al. describes phosphonoalkyl substituted pipecolic acid derivatives useful for treatment of nervous system disorders in mammals and as antagonists of the NMDA sensitive excitatory amino acid receptor, an example of which is cis-4-phosphonomethyl-2-piperidine carboxylic acid. West German Patent Application 3,736,016 of Sandoz describes phosphonoalkyl phenylglycines derivatives useful as anticonvulsant and as antagonists of the NMDA receptor, an example of which is 3-(phosphonomethyl)phenylglycine. U.S. application Ser. No. 111,749 filed Oct. 21, 1987 describes certain phosphonoalkylphenylglycine derivatives useful in reducing neurotoxic injury and as anticonvulsants and analgesics, an example of which is 4-(phosphonomethyl)phenylglycine.
Other classes of compounds have been tested as agonists in blocking NMDA- or KA-induced neurotoxicity [J. W. Olney et al., "The Anti-Excitotoxic Effects of Certain Anesthetics, Analgesics and Sedative-Hypnotics", Neuroscience Letters, 68, 29-34 (1986)]. The tested compounds included phencylidine, ketamine, cyclazocine, kynurenate and various barbiturates such as secobarbital, amobarbital and pentobarbital.
DESCRIPTION OF THE INVENTION
Control of neuropathological processes and the neurodegenerative consequences thereof in mammals is provided by treating a mammal susceptible to neurologic injury with a compound of a class characterized in having activity as antagonists at a major neuronal excitatory amino acid receptor site. This class of NMDA antagonist compounds is also expected to contain compounds having anti-convulsant and analgesic activity. Such NMDA antagonist compounds may be selected from a class of phosphono-hydroisoquinoline compounds defined by Formula I: ##STR2## wherein each of R 1 through R 3 is independently selected from hydrido, alkyl, haloalkyl, halo, cyano, nitro and groups represented by --OR 5 , --SR 5 , ##STR3## wherein R 5 is selected from hydrido, alkyl, aryl and aralkyl; and wherein R 4 is selected from hydrido, alkyl, acyl, aralkyl and ##STR4## and wherein each of Z 1 and Z 2 is independently selected from --OR 5 , SR 5 , ##STR5## wherein R 5 is defined as before; and wherein the A ring can be either saturated, partially unsaturated or fully unsaturated, i.e., an aromatic ring. Within this class of phosphono-hydroisoquinolines of the invention are the pharmaceutically acceptable salts of the compounds of Formula I, including acid addition salts, base addition salts including alkali metal salts. Also included within this class of compounds of the invention are tautomeric forms of the defined compounds and isomeric forms including diastereomers and enantiomers.
A preferred class of compounds within Formula I consists of those compounds wherein each of R 1 to R 3 is independently selected from hydrido, alkyl, halcalkyl, halo, cyano, nitro, --OR 5 and --SR 5 ; wherein R 5 is selected from hydrido, alkyl, aryl and aralkyl; and wherein R 4 is selected from hydrido, alkyl, acyl, aralkyl and --COOR 5 ; wherein each of Z 1 and Z 2 is independently selected from --OR 5 , --SR 5 , NR 4 R 5 and --OCHR 5 OCOR 5 ; and wherein the A ring can be either saturated, partially unsaturated or fully unsaturated (aromatic).
A more preferred class of compounds within Formula I consists of those compounds wherein each of R 1 to R 3 is independently selected from hydrido, alkyl, haloalkyl, halo, cyano, --OR 5 , wherein R 5 is selected from hydrido and alkyl; wherein R 4 is selected from hydrido, alkyl, acyl, aralkyl and --COOR 5 ; wherein each of Z 1 and Z 2 is independently selected from --OR 5 , NR 4 R 5 and --OCHR 5 OCOR 5 ; and wherein the A ring can be either saturated, partially unsaturated or fully unsaturated (aromatic).
An even more preferred class of compounds within Formula I consists of those compounds wherein each of R 1 , R 2 and R 3 is hydrido; wherein R 4 is selected from hydrido, alkyl, acyl, aralkyl and --COOR 5 ; wherein R 5 is selected from hydrido and alkyl; wherein each of Z 1 and Z 2 is independently selected from --OR 5 , NR 4 R 5 and --OCHR 5 OCOR 5 ; and wherein the A ring can be either saturated, partially unsaturated or fully unsaturated (aromatic).
A more highly preferred class of compounds within Formula I consists of those compounds wherein each of R 1 , R 2 and R 3 is hydrido; wherein R 4 is selected from hydrido, acyl and --COOR 5 ; wherein R 5 is selected from hydrido and alkyl; wherein Z 1 is selected from --OR 5 , NR 4 R 5 and --OCHR 5 OCOR 5 ; wherein Z 2 is hydroxyl; and wherein the A ring can be either saturated, partially unsaturated or fully unsaturated (aromatic).
A still more highly preferred class of compounds within Formula I consists of those compounds wherein each of R 1 , R 2 , R 3 , R 4 and R 5 is hydrido; wherein each of Z 1 and Z 2 is OH, and wherein the A ring can be either saturated, partially unsaturated or fully unsaturated (aromatic).
A most highly preferred class of compounds within Formula I consists of those compounds wherein each of R 1 , R 2 , R 3 , R 4 and R 5 is hydrido; wherein each of Z 1 and Z 2 is hydroxyl and wherein the A ring is fully unsaturated (aromatic).
An example of a specific, most highly preferred compound within Formula I is 5-phosphono-3-carboxy-1,2,3,4-tetrahydroisoquinoline. This compound exists as a racemic mixture, as the dextro-isomer and as the levo-isomer. Also, this compound may be in the form of a salt, including alkali metal salts such as the sodium salt.
The term "hydrido" denotes a single hydrogen atom (H) which may be attached, for example, to a carbon atom or to an oxygen atom to form an hydroxyl group. Where the term "alkyl" is used, either alone or within other terms such as "haloalkyl", "aralkyl" and "hydroxyalkyl", the term "alkyl" embraces linear or branched radicals having one to about ten carbon atoms. Preferred alkyl radicals are "lower alkyl" radicals having one to about five carbon atoms. The term "haloalkyl" embraces radicals wherein any one or more of the carbon atoms is substituted with one or more halo groups, preferably selected from bromo, chloro and fluoro. Specifically embraced by the term "haloalkyl" are monohaloalkyl, dihaloalkyl and polyhaloalkyl groups. A monohaloalkyl group, for example, may have either a bromo, a chloro, or a fluoro atom within the group. Dihaloalkyl and polyhaloalkyl groups may be substituted with two or more of the same halo groups, or may have a combination of different halo groups. A dihaloalkyl group, for example, may have two bromo atoms, such as a dibromomethyl group, or two chloro atoms, such as a dichloromethyl group, or one bromo atom and one chloro atom, such as bromochloromethyl group. Examples of a polyhaloalkyl are trifluoromethyl, 2,2,2-trifluoroethyl, perfluoroethyl and 2,2,3,3-tetrafluoropropyl groups. The term "alkylthio", as represented by the fragment --SR 5 , embraces radicals having a linear or branched alkyl portion of one to about ten carbon atoms attached to a divalent sulfur atom, such as a methylthio group. The term "alkoxy", as represented by the fragment --OR 5 , embraces radicals having a linear or branched alkyl portion of one to about ten carbon atoms attached to an oxygen atom, such as a methoxy group. The term "aryl" embraces aromatic radicals such as phenyl and naphthyl. The term "aralkyl" embraces aryl-substituted alkyl radicals such as benzyl, diphenylmethyl and triphenylmethyl. The terms "benzyl" and "phenylmethyl" are interchangeable.
The term "pharmaceuticaly acceptable salts" embraces forms of a salt of addition with a pharmaceutically utilizable acid, either an inorganic acid such as hydrochloric, hydrobromic, hydroiodic, nitric, carbonic, sulfuric or phosphoric acid, or an appropriate organic acid such as an aliphatic, cycloaliphatic, aromatic, araliphatic, heterocyclic, carboxylic or alkylsulfonic acid, specific examples of which are formic, acetic, propionic, succinic, glycolic, gluconic, lactic, malic, tartaric, citric, ascorbic, glucuronic, maleic, fumaric, pyruvic, aspartic, glutamic, benzoic, anthranilic, p-hydroxybenzoic, salicylic, phenylacetic, mandelic, embonic (pamoic), methanesulfonic, ethanesulfonic, 2-hydroxyethanesulfonic, panthotenic, benzenesulfonic, toluenesulfonic, sulfanilic, mesylic, cyclohexylaminosulfonic, stearic, alginic, β-hydroxybutyric, malonic, galactaric and galacturonic acid. Also embraced are metallic salts made from aluminium, calcium, lithium, magnesium, potassium, sodium and zinc, and organic salts made from benzathine (N,N'-dibenzylethylenediamine), chloroprocaine, choline, diethanolamine, ethylenediamine, meglumine (N-methylglucamine) and procaine.
The compounds of Formula I can possess one or more asymmetric carbon atoms and are thus capable of existing in the form of different, pure optical isomers as well as in the form of racemic or non-racemic mixtures thereof. All these forms fall within the scope of the present invention. The optical isomers can be obtained by resolution of the racemic mixtures according to conventional processes, for example, by formation of diastereomeric salts by treatment with an optically active acid, such as tartaric, diacetyltartaric, dibenzoyltartaric, ditoluoyltartaric and camphorsulfonic acid, followed by separation of the mixture of diastereomers by crystallization and then followed by liberation of the optically active bases from these salts. Separation of optical isomers may also be achieved by passing the isomer mixture through a chiral chromatography column optimally chosen to maximize the separation of the enantiomers of the products of the invention or derivatives thereof. Still another available method involves synthesis of covalent stereoisomeric molecules by reacting the compounds of the invention with an optically pure acid in an activated form or an optically pure isocyanate. The synthesized diastereoisomers can then be separated by conventional means such as chromatography, distillation, crystallization or sublimation and submitted to an hydrolytic step which will deliver the enantiomerically pure compound. The optically active compounds according to Formula I can likewise be obtained by utilizing optically active starting materials. All of these stereoisomers, optical isomers, diastereomers, as well as mixtures thereof, such as racemic mixtures, are within the scope of the invention.
A therapeutically-active compound of Formula I may be administered alone, or in a solvent, but is more likely to be included in a pharmaceutically-acceptable composition. Such pharmaceutical compositions may contain, as active ingredient, at least one compound of Formula I or its salt of addition with a pharmaceutically utilizable acid, and one or more suitable excipients. These compositions are prepared in such a manner that they can be administered by oral, rectal, parental or local route. The compositions can be solids, liquids or gel forms and may be utilized, according to the administration route, in the form of powders, tablets, lozenges, coated tablets, capsules, granulates, syrups, suspensions, emulsion solutions, suppositories or gels. These compositions can likewise comprise another therapeutic agent having an activity similar to or different from that of the compounds of the invention.
Other examples of specific compounds of Formula I are listed in Table I:
TABLE I______________________________________5-Phosphono-3-carboxy-1,2,3,4-tetrahydroisoquinolinehydrochloride;5-Phosphono-3-carboxy-1,2,3,4-tetrahydroisoquinoline;6-Methyl-5-phosphono-3-carboxy-1,2,3,4-tetrahydroisoquinoline;7-Methyl-5-phosphono-3-carboxy-1,2,3,4-tetrahydroisoquinoline;8-Methyl-5-phosphono-3-carboxy-1,2,3,4-tetrahydroisoquinoline;6-Chloro-5-phosphono-3-carboxy-1,2,3,4-tetrahydroisoquinoline;7-Chloro-5-phosphono-3-carboxy-1,2,3,4-tetrahydroisoquinoline;8-Chloro-5-phosphono-3-carboxy-1,2,3,4-tetrahydroisoquinoline;(D)-5-Phosphono-3-carboxy-1,2,3,4-tetrahydroisoquinoline;(L)-5-Phosphono-3-carboxy-1,2,3,4-tetrahydroisoquinoline;5-Phosphono-3-(ethoxycarbonyl)-1,2,3,4-tetrahydroisoquinoline;5-(Ethyl phosphono)-3-carboxy-1,2,3,4-tetrahydroisoquinoline;3-cis-carboxy-5-cis-phosphono-cis-2-azadecalin;3-cis-carboxy-5-trans-phosphono-cis-2-azadecalin;3-trans-carboxy-5-trans-phosphono-cis-2-azadecalin;3-trans-carboxy-5-cis-phosphono-cis-2-azadecalin;3-cis-carboxy-5-cis-phosphono-trans-2-azadecalin;3-cis-carboxy-5-trans-phosphono-trans-2-azadecalin;3-trans-carboxy-5-trans-phosphono-trans-2-azadecalin; and3-trans-carboxy-5-cis-phosphono-trans-2-azadecalin.______________________________________
Compounds of Formula I may be prepared in accordance with the following general procedure: ##STR6##
One process which can be used to synthesize the products of the invention starts with an ortho toluene derivative of Compound 1 where each of R 1 , R 2 and R 3 has the values defined previously and L is a good leaving group such as, for example, halogen, mesylate, tosylate, brosylate and acetate. These ortho toluene derivatives may be treated with dialkylphosphites in the presence of a palladium catalyst or treated first with magnesium in an aprotic anhydrous solvent to form the Grignard reagent which is then reacted further with a chloro dialkylphosphate reagent. The reaction is best achieved by mixing appropriate quantities of the reagents either neat or in a solvant like toluene, tetrahydrofuran, ether or in a protic solvent in the case of the palladium catalyzed reaction, according to the solubility of the reagents, and the reaction temperature can vary from about 0° C. to reflux of the reaction mixture. In the second step of the process, the methyl group of Compound 2 is oxidized to Compound 3. This step is best achived by treating Compound 2 with an agent able to deliver halogen atoms such as N-bromosuccinimide or N-chlorosuccinimide. The reaction is best conducted in an halogenated solvent such as chloroform, dichloromethane, tetrachloromethane or trichloroethylene at a temperature between 0° C. and reflux temperature of the solvent, with or without irradiation, and in the presence or not of a radical initiator such as azo-bisisobutyronitrile (AIBN). The leaving group is substituted in the third step with a glycine synthon such as diethylmalonate, acetamidomalonate (X=COOR 5 , Y=CH 3 CO), formamidomalonate (X=COOR 5 , Y=HCO), trifluoroacetamidomalonate (X=COOR 5 , Y=CF 3 CO), methylsulfonamidomalonate (X= COOR 5 , Y=CH 3 SO 2 ), N-(diphenylmethylene)glycine ethyl ester (X=H, Y=Φ 2 C=) or ethyl isocyanoacetate (X=H, Y=:C=). Compound 4 obtained from this reaction may require some transformation of the nitrogen substituent Y. For instance, the formamido, acetamido, isocyano and diphenylmethylene residues can be hydrolyzed to the free amine which will be either acylated or sulfonated to provide a compound more suitable for the experimental conditions of the next step. If dietbylmalonate has been used as the glycine synthon, it may be necessary to conduct a mono hydrolysis of the diester by stirring the compound in the presence of one equivalent of an alkali hydroxide such as lithium, sodium or potassium hydroxide at room temperature. The acid is carefully transformed into the azido acid either by the mixed anhydride method or by the use of a specific reagent such as diphenylphosphoryl azide. The azido acid is transformed into the amine by thermolysis in an aprotic solvent such as toluene and quenching of the isocyanate formed with dilute HCl.
The cyclization is best conducted by stirring Compound 4 in the presence of paraformaldehyde or trioxane and methanesulfonic acid in 1,2-dichloroethane or in an other chlorinated solvent. When R 4 is equal to acyl or alkoxycarbonyl, complete hydrolysis of Z 1 , Z 2 and R 4 can be acheived by an aqueous acid solution, such as 6N HCl or other mineral acid solution. Selective hydrolysis of R 4 can be achieved in an acidic alcoholic solution. Selective cleavage of Z 1 and Z 2 can be achieved by catalytic hydrogenation when Z 1 or Z 2 is benzyloxy. Various selective deprotection schemes are possible depending on the nature of R 4 , Z 1 and Z 2 . When R 1 , R 2 or R 3 is hydrolyzable the preferred method of deprotection is by catalytic hydrogenation of hydrogenolytically labile groups.
The perhydroisoquinolines can be prepared by the catalytic hydrogenation of the fully or partially deprotected tetrahydroisoquinolines 5 using various metal catalysts such as Pd, Pt, Ni, Ru and Rh. Partially hydrogenated material can be prepared by selective reduction methods, such as the Birch reduction, to obtain dienes followed by selective catalytic hydrogenation to obtain the mono-unsaturated products or the fully saturated compound. The advantage in using different methods of reduction is that different isomers could be obtained among the different racemic mixtures theoretically available.
The following Examples are detailed descriptions of the methods of preparation of compounds of Formula I. These detailed preparations fall within the scope of, and serve to exemplify, the above described general procedures which form part of the invention. These Examples are presented for illustrative purposes only and are not intended as a restriction on the scope of the invention. All parts are by weight unless otherwise indicated. Most of the commercially-available starting materials were obtained from Aldrich Chemical Co., Milwaukee, Wis.
EXAMPLE I ##STR7##
Diethyl 2-methylphenylphosphonate (6.84 gm) and N-bromosuccinimide (NBS) (5.87 gm) were combined in CCl 4 (60 mL). A small amount of azo-bisisobutyronitrile was added and the mixture was heated to reflux. After 6 hours, the NBS had been completely consumed and the orange colored reaction mixture had become a pale yellow. The reaction mixture was cooled to room temperature and the insoluble succinimide removed by filtration. Removal of the solvent on a rotary evaporator afforded a yellow oil. The oil was chromatographed on silica gel (125 gm) eluting with ethyl acetate. The appropriate fractions were pooled and concentrated to afford the product as a colorless oil. ##STR8## Sodium (82 mg) was dissolved in anhydrous ethanol (6 ml) under a nitrogen atmosphere. Diethyl formamidomalonate (725 mg) was then added with stirring. The reaction mixture became homogeneous and then a precipitate began to form. The reaction mixture was briefly heated to reflux and then allowed to cool. The 2-(diethylphosphono)benzyl bromide (1 gm) was then added and the reaction allowed to stir at room temperature for 20 hours. The reaction mixture was partitioned between H 2 O (30 ml) and Et 2 O (30 ml). The lower aqueous layer was extracted with fresh Et 2 O (30 ml) and the combined Et 2 O layers washed once with saturated NaCl (30 ml). The Et 2 O layer was then dried (MgSO 4 ) and concentrated to an oil. The oil was chromatographed on silica gel using ethyl acetate as the eluting solvent. The appropriate fractions were pooled and concentrated to afford the product as a clear oil. ##STR9## Diethyl 2-(2-(diethylphosphono)benzyl)formamidomalonate (430 mg) was combined with paraformaldehyde (31 mg) and acetic anhydride (94 μl) in 1,2-dichloroethane (3.6 ml) containing methanesulfonic acid (0.4 ml) and allowed to stir at room temperature for 7 days. The reaction mixture was diluted with Et 2 O (25 ml) and extracted with H 2 O (10 ml). The H 2 O layer was extracted with Et 2 O (25 ml) and the combined Et 2 O layers dried (MgSO 4 ) and concentrated to an oil. The oil was chromatographed on silica gel (50 gm) equilibrated with CH 2 Cl 2 . The column was eluted with CH 2 Cl 2 (100 ml), 1% EtOH/CH 2 Cl 2 (200 ml), and then the eluent was held at 2% EtOH/CH 2 Cl 2 . Fractions of about 10 ml were collected. A few minor impurities eluted followed by the product in fractions 71-79 and unreacted starting material in fractions 82- 92. The appropriate fractions were pooled and concentrated to an oil.
EXAMPLE II ##STR10##
N-Formyl-3-bis(ethoxycarbonyl)-5-(diethylphosphono)-1,2,3,4-tetrahydroisoquinoline (100 mg) was combined with 6N HCl (20 ml) and heated to reflux for 18 hours. The solvent was removed on a rotary evaporator and the resulting white solid dissolved in H 2 O (20 ml) and reconcentrated. This process was repeated with ethanol and the final product dried in vacuo.
Elemental Analysis
______________________________________ Theory + H.sub.2 O Found______________________________________C 38.54 38.10H 4.85 4.90N 4.49 4.34______________________________________
1 H NMR (D 2 O) δ* 3.38 (m,1H), 3.78 (m,1H), 4.40 (t,1H), 4.44 (m,2H), 7.36 (m,2H), 7.75 (m,1H).
BIOLOGICAL EVALUATION
Binding Assays
[Pullan, L. M., Olney, J. W., Price, M. T., Compton, R. P., Hood, W. F., Michel J., Monahan J. B., "Excitatory Amino Acid Receptor Potency and Subclass Specificity of Sulfur-Containing Amino Acids", Journal of Neurochemistry, 49 1301-1307, (1987)].
Synaptic plasma membranes (SPM) were prepared as previously-described [Monahan, J. B. and Michel, J., "Identification and Characterization of an N-methyl-D-aspartate-specific L[ 3 H]glutamate Recognition Site in Synaptic Plasma Membranes, J. Neurochem., 48, 1699-1708 (1987)]. The SPM were stored at a concentration of 10-15 mg/ml in 0.32M sucrose, 0.5 mM EDTA, 1 mM MgSO 4 , 5 mM Tris/SO 4 , pH 7.4, under liquid nitrogen. The identity and purity of the subcellular fractions were confirmed by both electron microscopy and marker enzymes. Protein concentrations were determined by using a modification of the method of Lowry [Ohnishi, S. T. and Barr, J. K., "A Simplified Method of Quantitating Proteins using the Biuret and Phenol Reagents", Anal. Biochem., 86, 193-197 (1978)].
The SPM were treated identically for the [ 3 H]AMPA (QUIS), [ 3 H]kainate and sodium-dependent L-[ 3 H]glumatate binding assays. The SPM were thawed at room temperature, diluted twenty-fold with 50 mM Tris/acetate, pH 7.4, incubated at 37° C. for 30 minutes, and centrifuged at 100,000 g for 15 minutes. The dilution, incubation and centrifugation were repeated a total of three times.
Prior to use in the NMDA-specific L-[ 3 H]glutamate binding assay, the SPM were thawed, diluted twenty fold with 50 mM Tris/acetate (pH 7.4 containing 0.04% (v/v) Triton X-100), incubated for 30 minutes at 37° C. and centrifuged as described above. The Triton X-100 treated membranes were washed with 50 mM Tris/acetate (pH 7.4) and centrifuged at 100,000 g for 15 minutes a total of four times.
The basic procedure for the receptor subclass binding assays was similar. This general method involved adding the radioligand (12.5 nM L-[ 3 H] glutamate; 0.5 nM [ 3 H]kainate or 10 nM [ 3 H]AMPA) to the appropriate concentration of the test compound and initiating the assay by the addition of ice cold synaptic plasma membranes (0.2-0.45 mg). The binding assays were performed in 1.5 mL centrifuge tubes with the total volume adjusted to 1.0 mL. Additions of test compounds were made in 50 mM Tris/acetate (pH 7.4) and incubations were carried out at 0°-4° C. The incubation time for each of the NMDA and the AMPA binding assays was 10 minutes, for the kainate binding assay 60 minutes and for the sodium-dependent glutamate binding assay 15 minutes. The AMPA binding assay contained 100 mM KSCN and the sodium-dependent glutamate binding assay contained 150 mM sodium acetate in addition to the previously described reagents.
To terminate the incubation, the samples were centrifuged for 15 minutes at 12,000 g and 4° C. in a Beckman Microfuge 12. The supernatant was aspirated and the pelleted membranes dissolved in Beckman BTS-450 tissue solubilizer for a minimum of 6 hours at room temperature. Beckman MP scintillation cocktail containing 7 mL/1 acetic acid was then added and the samples counted on a Beckman LS 5800 or 3801 liquid scintillation counter with automatic corrections for quenching and counting efficiency.
Nonspecific binding was defined as the residual binding in the presence of either excess L-glutamate (0.1-0.4 mM), kainate (0.01 mM), or NMDA (0.5 mM), and was 15-25% of the total binding in the NMDA binding assay, 19-27% in the AMPA binding assay, 20-30% in the kainate binding assay and 10-15% in the sodium-dependent binding assay. Radioligand binding to the synaptic plasma membranes was analyzed using Scatchard and Hill transformations and the K i values of the compounds determined using logit-log transformations. Calculations and regression analysis were performed using templates developed for Lotus 1, 2, 3 as previously described [Pullan, L. M. "Automated Radioligand Receptor Binding Analysis with Templates for Lotus", Computer Appln. Biosci., 3 131 (1987)]. Binding results are reported in Table II for example compounds of the invention. Included in Table II are binding data for D,L-AP7[D,L-2-amino-7-phosphonoheptanoic acid].
TABLE II______________________________________RECEPTOR BINDING DATA Binding (μM)Compound NMDA KA Quis______________________________________D,L-AP7 5.4 >300 >300D-AP7 4.0 >300 >300Ex. II 1.6 ˜300 >300______________________________________
TCP Modulation Assay
The effect on the TCP (1-[1-(2-thienyl)-cyclohexyl]piperidine) binding was measured in rat brain synaptic membranes (SPM) prepared as previously described [J. B. Monahan & J. Michel; J. Neurochem. 48:1699-1708 (1987)]. Prior to their use in the binding assay, frozen SPM were thawed, diluted twenty fold with 50 mM Tris/acetate (pH 7.4 containing 0.04% (v/v) Triton X-100), incubated for 30 min. at 37° C. and centrifuged at 95,000 xg for 15 min. The Triton X-100 treated SPM were washed with 5 mM Tris/HCl, pH 7.4 and centrifuged a total of six times. The compound of Example II was incubated at different concentrations with SPM (0.2-0.4 mg protein) and 2 nM tritiated TCP, in a total volume of 0.5 ml of 5 mM Tris/HCl buffer pH 7.4 at 25° C. for 60 min. The samples were filtered through glass fiber filters (Schleicher & Schuell #32) which have been pretreated with 0.05% (v/v) polyethylenimine, washed 4 times with 2 ml of ice-cold 5 mM Tris/HCl buffer, and then counted on a Beckman LS 5800 liquid scintillation counter with automatic corrections for quenching and counting efficiency. Inhibition of TCP binding was measured as a decrease in the binding in the presence of 0.05 mM L-glutamate. Non-specific binding was defined as the residual binding in the presence of 60 mM phencyclidine.
Result
The compound of Example II inhibits 64% of TCP binding at 5 μM and 91% at 50 μM.
Administration of compounds within Formula I to humans can be by any technique capable of introducing the compounds into the bloodstream of a human patient, including oral administration, and by intravenous, intramuscular and subcutaneous injections.
Compounds indicated for prophylactic therapy will preferably be administered in a daily dose generally in a range from about 0.1 mg to about 100 mg per kilogram of body weight per day. A more preferred dosage will be a range from about 1 mg to about 100 mg per kilogram of body weight. Most preferred is a dosage in a range from about 1 to about 50 mg per kilogram of body weight per day. A suitable dose can be administered, in multiple sub-doses per day. These sub-doses may be administered in unit dosage forms. Typically, a dose or sub-dose may contain from about 1 mg to about 100 mg of active compound per unit dosage form. A more preferred dosage will contain from about 2 mg to about 50 mg of active compound per unit dosage form. Most preferred is a dosage form containing from about 3 mg to about 25 mg of active compound per unit dose.
The active compound is usually administered in a pharmaceutically-acceptable formulation, although in some acute-care situations a compound of Formula I may be administered alone. Such formulations may comprise the active compound together with one or more pharmaceutically-acceptable carriers or diluents. Other therapeutic agents may also be present in the formulation. A pharmaceutically-acceptable carrier or diluent provides an appropriate vehicle for delivery of the active compound without introducing undesirable side effects. Delivery of the active compound in such formulations may be by various routes including oral, nasal, topical, buccal and sublingual, or by parenteral administration such as subcutaneous, intramuscular, intravenous and intradermal routes.
Formulations for oral administration may be in the form of capsules containing the active compound dispersed in a binder such as gelatin or hydroxypropylmethyl cellulose, together with one or more of a lubricant, preservative, surface-active or dispersing agent. Such capsules or tablets may contain controlledrelease formulation as may be provided in a dispersion of active compound in hydroxypropylmethyl cellulose.
Formulations for parenteral administration may be in the form of aqueous or non-aqueous isotonic sterile injection solutions or suspensions. These solutions and suspensions may be prepared from sterile powders or granules having one or more of the carriers or diluents mentioned for use in the formulations for oral administration.
Although this invention has been described with respect to specific embodiments, the details of these embodiments are not to be construed as limitations. Various equivalents, changes and modifications may be made without departing from the spirit and scope of this invention, and it is understood that such equivalent embodiments are part of this invention.
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A class of phosphono-hydroisoquinoline compounds is described for treatment to reduce neurotoxic injury associated with anoxia or ischemia which typically follows stroke, cardiac arrest or perinatal asphyxia. The treatment includes administration of a phosphono-hydroisoquinoline compound alone or in a composition in an amount effective as an antagonist to inhibit excitotoxic actions at major neuronal excitatory amino acid receptor sites. Compounds of most interest are those of the formula: ##STR1## wherein each of R 1 through R 4 is hydrido, each of Z 1 and Z 2 is hydroxyl and wherein the A ring is saturated.
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BACKGROUND ART
[0001] The invention generally relates to the treatment of materials, and in particular for treating a semiconductor material for subsequent bonding. The technique includes bombarding a surface of the semiconductor material with a beam containing a controlled number of ions in ion clusters. The beam etches a pattern in the surface, and the number of ions is controlled to provide a desired roughness of the surface pattern to improve adhesion during subsequent bonding. The invention may be applied to substrates for use in electronics, optics and optoelectronics.
[0002] Processes for manufacturing detachable substrates are known. Such processes use two layers of material, for example semiconductor materials such as silicon, to fabricate “detachable” substrates. The expression “detachable” substrate means a substrate that comprises two layers that have been bonded together, wherein the bonding is reversible so that it is possible to separate the two layers along their bonding interface. Detachable substrates thus include two layers integrally attached at a bonding interface. The cohesion energy between the two layers is controlled so that it is sufficiently great to guarantee good cohesion of the two layers forming the detachable substrate, even when the substrate is subject to thermal and/or mechanical treatments (for example, thermal treatments such as high temperature annealing, and mechanical treatments such as polishing the substrate surface). The cohesion energy is also sufficiently small so that the layers can be separated at a weakened zone formed between the two layers if desired (for example after the substrate has been subject to certain treatments). Typically the two layers of the detachable substrate are detached via a mechanical action, for example by use of an object such as a blade.
[0003] The term “bonding” in the context of the treatment of very thin layers means to put two layers into contact to create links, via molecular adhesion, between the bonded surfaces of the two layers. These links may typically be hydrogen links, and their development can be stimulated by pre-treating the layers that are to be bonded.
[0004] Pre-treatments applied prior to bonding can, for example, include a cleaning stage that consists of dipping the layers successively in an alkaline bath and then in an acid bath. The layers are dipped in an alkaline bath to develop the hydrophilic properties of the layers, by creating OH type links on the surface of the layers. The acid bath eliminates any contaminating elements (in particular metals) from the surface of the layers that may have been generated during previous treatments of the layers (and in particular the alkaline bath). Pre-treatment can also involve exposing the layers to a plasma, for example, or may include other known techniques.
[0005] The surface condition of the layers to be bonded is subject to very strict specifications, especially when the layers are to be used to manufacture substrates for electronics, optics or optoelectronics applications. It is thus common to have to meet roughness specifications which must not exceed a few Angstroms in rms value (root mean square).
[0006] Roughness is generally measured with an AFM (Atomic Force Microscope). This equipment can measure the roughness on a scanned surface by using the tip of the AFM, ranging from 1×1 μm 2 to 10 ×10 μm 2 , and in rare cases from 50×50 μm 2 , or even 100×100 μm 2 . Since the surface condition of these layers are generally very smooth, bonding s accomplished by simply contacting the surfaces of the two layers together. In some cases, such bonding may be complemented by compressing the structure made of the two layers.
[0007] It is known to make detachable substrates by applying a surface condition adjustment treatment to the surface of at least one of the two layers to be bonded. Such a surface condition adjustment treatment consists of applying a “wet” etching treatment to the surface, which means using a liquid to attack the surface to adjust its roughness. For example, the surface to be treated may be an oxide, and the liquid may be hydrofluoric acid. The surface oxide may be in particular a silicon dioxide. Attacking the surface with a liquid permits one to modify the surface as desired, such as to increase its roughness to a desired level. For example, to modify the surface so that it can bond with another layer, but also allow for separation of the bond later via a mechanical action. The desired roughness (typically a roughness of about 5 Angstroms rms to make a detachable substrate) is achieved by controlling the length of time the surface is exposed to the liquid.
[0008] Thus, one of the known techniques to make detachable substrates involves attacking the surface of at least one layer with a liquid, in order to increase the roughness of this surface. An inconvenience of such methods is that some parts of the layer that should not be attacked may happen to be exposed to the liquid. Consequently, when only one side of a layer should be treated, the opposite side of the layer may happen to be attacked considerably by the liquid.
[0009] It is possible to protect certain parts of the layer during wet etching. For example, the parts could be covered with a protective element, for example a varnish. But this implies the use of specific and complex equipment. Moreover, such protective means do not necessarily make it possible to systematically prevent the liquid from attacking certain other parts (notably the lateral parts of the layer). In addition, implementing such protective means may require additional handling of the layers, and thus additional risks of damaging these layers (which may be extremely fragile, particularly in the case of thin layers as mentioned above).
[0010] Moreover, if the purpose is to control the spatial distribution of side regions of a layer whose roughness is to be adjusted via the known technique of wet etching, it is necessary to plan for relatively heavy and complex means and a complicated protocol in order to only etch the desired side regions. It is necessary to cover the side of the layer with a mask to form a spatial pattern which allows access to only the regions which are to be etched (positive mask), or prevents access to only regions which are to be protected from etching (negative mask). The layer to be etched and its mask are exposed to wet etching. It is then necessary to remove the mask. This is achieved via chemical products and/or via exposure to a plasma. Such means to remove the mask are likely to damage the surface of the layer, and/or leave some contaminating elements on the surface. These contaminating elements can in particular be hydrocarbons issued from the resin that formed the mask. The hydrocarbons then are an obstacle to bonding the layer via molecular adhesion. Consequently, manufacturing a detachable substrate from such a layer is difficult.
[0011] Thus, it appears that known solutions for making detachable substrates have limitations.
SUMMARY OF THE INVENTION
[0012] The invention relates to a method for treating a semiconductor material for subsequent bonding. The technique includes bombarding a surface of the semiconductor material with a beam containing a controlled number of ions in ion clusters. The beam etches a pattern in the surface, and the number of ions is controlled to provide a desired roughness of the surface pattern to improve adhesion during subsequent bonding.
[0013] In an advantageous embodiment, the method also includes bonding the surface layer of the semiconductor material to a second surface of a semiconductor substrate to form a detachable substrate structure. In a preferred implementation, the ions are of a chemically inert species in relation to the semiconductor material, and the semiconductor material may be made of at least one of silicon or silicon carbide, and the ions may be argon ions or nitrogen ions. In a variation, the surface is bombarded with ions that are capable of chemically reacting with the semiconductor material, and the ions may be generated from a plasma. When the ions are capable of reacting with the semiconductor material, the surface layer and the plasma may respectively be of Si and SF 6 , SiC and SF 6 /O 2 , SiO 2 and SF 6 /O 2 , SiO 2 and CHF 3 /SF 6 , Si 3 N 4 and CHF 3 /O 2 /SF 6 .
[0014] In a beneficial implementation according to the invention, the number of ion clusters is controlled to smooth the surface to a roughness value suitable for molecular bonding. The number of ions may be controlled by controlling the pressure of an ion source that generates ion clusters. In addition, an acceleration voltage that is applied to the beam may be controlled to control the speed of the ion clusters which influences the etching of the surface. In a preferred embodiment the ion clusters are directed to selectively treat desired zones of the surface to create an adjusted pattern.
[0015] In another advantageous embodiment, the invention includes focusing the beam such that the ions, monomer species of the ions, and the ion clusters are directed towards the surface of the semiconductor material. Moreover, the beam of ion clusters may be directed to a selected impact site on the surface of the semiconductor material, and the semiconductor material may be moved to provide the desired pattern. An appropriate spatial pattern can thus be created on the surface layer having a different roughness in comparison to other portions of the surface. Furthermore, a plurality of patterns with variable roughness can be created on the surface.
[0016] Advantageously, according to the invention, the semiconductor material is one that is recycled after removal of a transfer layer. In addition, the semiconductor material may include at least one layer of a material that is different than the semiconductor material, with the outer surface of the layer being etched by the bombarding. Preferably, at least two layers of materials that are different than the semiconductor material can be provided, such as a buried layer and an insulating layer, with the outermost layer being the surface that is etched prior to bonding.
[0017] The present invention thus overcomes the limitations of the prior art, and further allows for precisely controlling the surface condition (and in particular the roughness) of a layer of semiconductor material that will be used to assemble a detachable substrate. In particular, the present invention permits fine adjustments of the roughness of the surface, and permits the selection of either increasing or reducing the roughness of the surface. Moreover, the invention permits local adjustments to be made to the surface of semiconductor material, and the adjustments can be made according to a predetermined spatial pattern, without being subject to the inconveniences associated with conventional treatment methods.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Other aspects, purposes and advantages of the invention will become clear after reading the following detailed description with reference to the attached drawings, in which:
[0019] [0019]FIG. 1 is a schematic diagram of an installation for bombarding a wafer with ion clusters according to the invention;
[0020] [0020]FIGS. 2 a and 2 b are graphs that represent the evolution of the roughness of a surface that has been bombarded with ion clusters, under different conditions according to the invention;
[0021] [0021]FIG. 3 is a histogram illustrating the influence of pressure upon ion generation, in particular the creation of ion clusters.
[0022] [0022]FIGS. 4 a to 4 c illustrate a particular implementation of the invention, in which a surface is selectively and locally treated to adjust its surface condition according to a desired pattern.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0023] [0023]FIG. 1 illustrates an implementation of an installation 10 for bombarding a layer 20 of material with a beam 30 of ion clusters. The word “ions” may designate ions that are “pure”, but also may designate species created from several ions and which are electrically charged. Generally speaking, the “clusters” as used herein, are globally ionized, meaning that they have an electric charge other than 0. But these clusters can further include ions of other species, including molecules.
[0024] The layer 20 is of a semiconductor material. As will be explained below, it can either be silicon or silicon carbide, or another semiconductor material (SiO2 or Si3N4, for example).
[0025] The installation 10 comprises a source 101 of pressurized gas, capable of generating a parallel beam of gas ion clusters from a plasma internal to the source 101 . The gas used can for example be argon or nitrogen. The control of the characteristics of the plasma allows for defining the configuration of the ion clusters. In particular, the pressure of the plasma source 101 is controlled in order to control the average number of ions present in the clusters, as will be explained in detail below with regard to FIG. 3. In addition, control of the acceleration voltage allows for controlling the speed of these clusters.
[0026] The layer 20 is a layer whose surface conditions are to be modified in a controlled manner so that it can be assembled, via bonding, with another layer (whose surface condition may also have been adjusted) to create a detachable substrate.
[0027] According to a first alternate implementation, ion clusters such as those described above are projected onto the surface of the layer 20 , and this bombardment includes no chemical reactions. In this case the bombardment is thus purely “ballistic”, because the ion clusters are chemically inert in relation to the material of the layer 20 . In such a case, the bombarded clusters are typically made of argon or nitrogen.
[0028] According to another alternative implementation, ion clusters of a particular species capable of chemically reacting with the material of the layer 20 could be used. In this case the bombardment is said to be reactive, and the bombarded ions can be made of oxygen or an oxygen compound.
[0029] In the case of a reactive bombardment of ions, it is also possible to further utilize an etching plasma (that is different from the plasma of the source 101 ) in a zone of the device 10 through which the ion beam will need to pass, and which is located in the region of the device 10 that is immediately upstream from the layer 20 . In the particular embodiment including an etching plasma, it can for example be planned that the material of the surface of the layer 20 and the plasma element consist of one of the following pairs: (Si, SF 6 ), (SiC, SF 6 /O 2 ), (SiO 2 , SF 6 /O 2 ), (SiO 2 , CHF 3 /SF 6 ), (Si 3 N 4 , CHF 3 /O 2 /SF 6 ). In this case, the ion clusters created by the source 101 chemically react with the etching plasma. In addition, the etching plasma itself can also chemically react with the surface of the layer, as well as the species having passed through the etching plasma with the layer.
[0030] Referring again to FIG. 1, the installation 10 shows that the ion beam is generated by the source 101 and then passes through an accelerating chamber 102 . The chamber 102 accelerates the ions clusters of the beam from the source 101 to a desired velocity, thanks to an acceleration electric voltage which can be controlled. In this text the “acceleration voltage” of the source 101 actually corresponds to the acceleration voltage of the accelerating chamber 102 .
[0031] The beam then passes through a beam-creating electromagnetic structure 103 . This structure 103 allows adjustments to the characteristics of the magnetic field of the beam (i.e. to collimate or focus the beam), via the application of electromagnetic fields with desired characteristics. The beam then passes through a magnetic annular structure 104 which also allows for the creation of a field with controlled characteristics, in order to selectively deviate the charged species of the ion beam The beam issued from the accelerating chamber 102 and the electromagnetic structure 103 comprises ion clusters of the bombarded species, but also molecules which are electrically neutral (in particular monomers of the bombarded species). The trajectory of the different elements of the beam is represented in FIG. 1 as being rectilinear. However, in reality these trajectories are not rectilinear, and the radius of curvature of the trajectory depends on the mass of the ions and of the different elements of the beam. By precisely controlling the characteristics of the magnetic field generated by the magnetic annular structure 104 , it is possible to selectively deviate only the desired ion clusters towards the opening of a screen 106 . The other constituents of the beam do not pass through this opening because they are stopped by the screen 106 .
[0032] In a variation, the structure 103 and the structure 104 can be one and the same. In addition, an electrical neutralizing structure 105 may also be provided.
[0033] A screen 106 with an opening 1060 is positioned to let pass only the part of the beam that comprises the desired clusters, so that the desired ion clusters can have an impact on the layer 20 located behind the opening 1060 . The screen 106 and its opening 1060 may be fixed parts of the device. The portion of the beam that passes through the opening to impact the layer 20 corresponds to a focalized beam, after the beam passes through of the means 103 . Therefore, the layer 20 is impacted by the beam of ion clusters over a basic surface of very small dimensions (the section of the beam that passes through the opening 1060 has a width of about one or possibly only about a few millimeters). The layer 20 in this implementation is mounted on a movable support 107 , which can be controlled to displace the layer 20 in the plane perpendicular to the beam, for example.
[0034] It is thus possible to precisely define an etching pattern of the ion clusters on the surface of the layer 20 , by displacing the layer according to a desired trajectory using the moveable support 107 . In this manner, the impact site of the ion clusters on the layer 20 traces a special pattern. This aspect will be further considered later.
[0035] Again referring to FIG. 1, the installation 10 also includes a screened room 108 located behind the layer 20 and the displacement means 107 , which faces the impact zone of the beam on the layer 20 . This screened room 108 is connected to a device 109 capable of determining the dose of species received by the layer 20 .
[0036] The bombardment of the layer 20 with ion clusters of desired characteristics thus allows for adjusting the roughness of the surface, with the aim of making a detachable substrate. It is to be noted that, in comparison with known techniques to modify the surface conditions via wet etching, the bombardment with ion clusters avoids the inconveniences described above. In particular, no “leak” or contamination can occur because the present technique modifies the surface roughness by using a “dry” etching technique, and not a “wet” etching method. Thus, the layer 20 does not come into contact with liquids.
[0037] Moreover, the present installation and method permits very precise control of the impact zone to be bombarded on the surface with the ion clusters. This is also true for the situation wherein the layer is not displaced, as the dimensions of the section of the beam that impact the layer are very small, as already mentioned. Further, the fact that the bombardment occurs not simply with ions but with clusters of ions, allows for great freedom to adjust the surface roughness of the layer 20 . In particular, it is possible to selectively reduce, or increase, the surface roughness of the layer 20 .
[0038] It has been observed that, depending on the characteristics of the bombardment with ion clusters, it is possible to either increase or reduce the roughness. In particular, with reference to FIG. 2 a, schematically represented are several curves C 1 to C 5 that are substantially rectilinear. These curves translate the evolution of the roughness R of the surface of the layer 20 , versus the evolution of the voltage V applied to the beam inside the accelerating chamber 102 . Each of the curves in FIG. 2 a corresponds to a bombardment condition in which the ion clusters mainly comprise a respective number of ions. The control of the bombardment parameters allows a determination of the number of ions present in the clusters that bombard the layer 20 . The main parameter that controls the number of ions present in the clusters is the pressure inside the ion source 101 . Thus, the pressure of the source 101 can be controlled to control the number of ions in the clusters. This is illustrated on the histogram in FIG. 3.
[0039] [0039]FIG. 3 shows several curves A 1 , A 2 , A 3 , A 4 . Each of these curves represents the size repartition of the ion clusters, for a given source pressure. The size of the clusters is represented by the number of atoms per cluster (upper horizontal scale), which here varies from 0 to 3000 atoms per cluster. The lower curve A 1 is associated with a pressure of 760 Torr, the curve A 2 with a pressure of 2300 Torr, the curve A 3 with a pressure of 3000 Torr, and the curve A 4 with a pressure of 3800 Torr. The peak of these curves which corresponds to the most common cluster size for the pressure in question, has greater values as the pressure increases. This histogram was taken form the article entitled: “Materials processing by gas cluster ion beams”, Material Science and Engineering, R34, N o 6, p244 (2001). Thus, as shown, the number of ions present in each cluster lies around an average number “N” of ions per cluster. It is thus possible to control the value of N by controlling the pressure of the ion source.
[0040] Each curve in FIG. 2 a thus corresponds to a different value of N. The value of N increases when the curve changes from C 1 to C 2 , to C 3 , to C 4 , and to C 5 . The curve C 1 corresponds to a bombardment with individual ions, which means that N equals 1. Under these conditions, as the acceleration voltage of the ions of the beam increases, the surface roughness of the layer 20 subject to bombardment of “clusters”, each made of a single ion, increases considerably. In this situation, the ions individually bombard the layer and cause major damage to the surface structure of the layer.
[0041] The curve C 2 , immediately below the first curve, corresponds to bombardment conditions under which N has a value greater than 1. In this case the same increase in acceleration voltage does not result in as great an increase of the surface roughness, even though the roughness does increase. The next curve C 3 illustrates a low increase of roughness for the same increase in the voltage V. Lastly, the curve C 4 corresponds to bombardment conditions under which the bombarded clusters comprise a rather large number of ions, and it illustrates a constant roughness despite the increase in the acceleration voltage V.
[0042] Thus, when the ion clusters comprise a number N of ions greater than a given threshold, the slope of the resulting curves Rf(V) approaches zero, under certain conditions. This threshold depends on the starting surface condition of the layer, prior to bombardment. Moreover, when the number N continues to increase, bombardment does not increase the surface roughness of the layer 20 , but rather reduces it by smoothing this surface. This situation is illustrated by the curve C 5 .
[0043] By adjusting bombardment conditions, and more precisely the number of ions present in the clusters, it is possible to adjust the surface condition of the layer 20 in a desired manner by increasing to a greater or lesser extent the surface roughness of this layer, or even by reducing the roughness. This is useful in cases where the surface of the layer 20 has a high roughness before bombardment.
[0044] Consequently, two parameters define bombardment conditions that have a major influence on the progression of the process. First, the pressure associated with generating ions allows one to control the number of ions present in the clusters. Second, the acceleration voltage allows one to control the speed of the clusters, and also has an influence as described with reference to FIGS. 2 a and 2 b. This influence can be exploited by programming bombardment sequences during which different regions of the layer 20 are subject to cluster bombardments of different numbers of ions, to selectively adjust the surface roughness of the different regions in a desired manner. For this purpose, the means of displacement 107 may advantageously be programmed to displace the layer 20 in conjunction with changes to the parameters to modify the value of N during different successive stages of a given bombardment process of the layer.
[0045] [0045]FIG. 2 b represents the evolving surface roughness R of the layer 20 subject to bombardment with ion clusters that includes an average number N of ions which can vary (here again corresponding to different curves in this figure), versus the acceleration voltage V. This Figure includes the curves C 1 to C 5 of FIG. 2 a. However, FIG. 2 b also shows another set of curves C′ 1 to C′ 5 , which progress according to the same general logic as the curves C 1 to C 5 (increase in the number N from curve C′ 1 to curve C′ 5 , for the same starting layer 20 and the same bombarded ions).
[0046] The curves C′ 1 to C′ 5 show that, contrary to the curves C 1 to C 5 , an increase in the number N does not result in a reduction of the surface roughness of the layer 20 . The curve C′ 5 corresponds to a number N that is very large, which can be associated with a value of N that approaches infinity. It should be noted that when the surface condition of the layer 20 already corresponds to a low roughness (curves C′ 1 to C′ 5 ), it is impossible to further smooth the surface by increasing N. Thus, starting with a layer whose surface is relatively rough, it is possible to selectively increase, or reduce, the roughness.
[0047] An interesting application of the present method is when a surface layer 20 of a wafer has surface conditions that are incompatible with bonding via molecular adhesion (roughness greater than a value of about 5 Angstroms rms). The present invention can be used to advantageously treat certain regions of these wafers to smooth them and bring these regions to a roughness value that enables such bonding. In particular, this allows for the recycling of donor wafers resulting from use of a layer transfer process such as the SMART-CUT® type process, by reusing them. In this case, it is possible to use layers made from a wafer whose intrinsic surface condition is incompatible with bonding (for example, SiC, III-V). Instead of proceeding to completely polish such a wafer, a bombardment with clusters comprising a rather large number N of ions makes it possible to smooth the surface of the wafer.
[0048] Moreover, the smoothing process can be precisely controlled, both in terms of the final roughness and in terms of creating a spatial pattern having more or less smooth regions with the aim of using the surface for bonding. However, if the starting surface condition of the layer 20 is inferior (less than a given threshold R 0 ), which depends among other things on the nature of the material of the layer and of the bombarded species, it will only be possible to increase the roughness. Thus, if the starting point of the curves C′ 1 to C′ 5 happened to be below the threshold R 0 (whereas it is situated at the level of this threshold in FIG. 2 b ), it would not even be possible to retain this starting low roughness by proceeding with a bombardment of the surface. In particular, even a bombardment with a very great value of N would result in an increase of the roughness.
[0049] [0049]FIGS. 4 a to 4 c represent layers 20 that have been subject to a bombardment with ion clusters such as that described above, during which the roughness of certain regions of the surface of the layer have been selectively modified. FIG. 4 a shows a ring on the surface which has been created to have a roughness value lower than that of the rest of the surface, so that mechanical stability can be obtained on this ring when at the time of assembling the layer 20 with another layer (which may be homogeneously smooth, for example).
[0050] The displacement device 107 may be programmed to create any other desired pattern on the surface. FIGS. 4 b and 4 c thus respectively represent a layer 20 with a grid pattern, and with a paved pattern, each having a roughness lower than that of the rest of the surface of the layer. Further, by controlling the number N of ions in the bombarded clusters in conjunction with the displacement of the layer 20 , it is thus possible to create any pattern, including one with several levels of roughness selectively distributed over different desired regions of the surface. It is then possible to create patterns with variable roughness, to make detachable substrates having a controlled distribution of roughness over the surface. The expression “pattern with variable roughness” designates a pattern wherein different zones may have different roughness values.
[0051] It is to be noted that the present technique allows for the very fine control of the levels and distributions of roughness on the surface of a layer from which a detachable substrate is to be created, after conducting a reversible bonding process via molecular adhesion with another layer (whose roughness may have been adjusted if necessary).
[0052] It is also noted that proceeding with a bombardment with ion clusters only modifies the surface of the layer 20 , no subsurface damage occurs by using such a bombardment process. In this regard reference can be made to the article “Substrate smoothing using gas cluster ion beam processing” by Allen and al., Journal of Electronic Materials, Vol. 30, N o 7, 2001.
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A method for treating a semiconductor material for subsequent bonding. The technique includes bombarding a surface of the semiconductor material with a beam containing a controlled number of ions in ion clusters. The beam etches a pattern in the surface, and the number of ions is controlled to provide a desired roughness of the surface pattern to improve adhesion during subsequent bonding.
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BACKGROUND OF THE INVENTION
This is a continuation-in-part of copending U.S. patent application Ser. No. 649,736, filed Jan. 16, 1976, which in turn is a continuation of U.S. patent application Ser. No. 426,197, filed Dec. 19, 1973, both now abandoned. The subject matter of these applications are incorporated herein by reference thereto.
This invention relates to an improved excessive speed and theft deterrent system for automative vehicles.
With the increased scarcity of fuel recently experienced, it has become increasingly critical that motor vehicles, such as automobiles, trucks and buses, be operated at their most efficient speed level. To achieve this vehicle operators have been asked to maintain preselected speed limits by state and local governments either on a mandatory basis or on a voluntary basis. However, a vehicle operator often does not pay close attention to the speed with which he is driving and indeed may be less than concerned with the speed of the vehicle. Accordingly, vehicle speed warning systems are becoming increasingly important in order to remind drivers when they approach or exceed the posted speed limit. Further, owners of fleets of vehicles such as the government and certain large businesses have set speed limits at which their vehicles operate most efficiently. However, such fleet owners have no way of determining whether their employees are complying with the speed limits imposed. Thus, these fleet owners must rely upon local law enforcement to regulate the speed with which their vehicles are being operated. Accordingly, there is a need for an apparatus for determining not only when the speed limit is being exceeded but also the amount of time during which a vehicle has been operated above the imposed speed limit. Such an apparatus would give an accurate indication to the vehicle operator of the total amount of time in which the vehicle has been operated over the speed limit in a predetermined unit of time, such as, for example, a day or a week.
In addition, the theft of idling or parked vehicles has become an increasing problem. For example, cars or trucks which are temporarily parked but which are idling are a prime target for those who would wish to illegally appropriate the vehicle. Further, even cars which are parked with the engine off are frequent targets for those who would wish to illegally take and use the vehicle. Accordingly, there is a need for a simple, inexpensive and foolproof apparatus for preventing the theft of parked and/or idling vehicles.
It therefore is an object of this invention to provide an improved excessive speed and theft deterrent system for motor vehicles.
SHORT STATEMENT OF THE INVENTION
Accordingly, this invention relates to an excessive speed and theft deterrent system for motor vehicles which comprises a means for generating a signal having a magnitude which is proportional to the speed of the vehicle. The system includes a means for comparing the signal representing the speed of the vehicle with a voltage which is proportional to a predetermined speed limit. The comparing means provides an output when the speed of the vehicle exceeds the predetermined speed limit which output initiates the generation of a pulse train after a predetermined time delay. The pulse train has a predetermined frequency and is counted in a counter to determine the total time in which the vehicle has exceeded the selected speed limit. The time delay in the generation of the pulse train is to permit temporary increases in speed over the speed limit so that the vehicle can pass slower moving vehicles safely.
A scaling means is provided for varying the relative comparison levels of the speed proportional signal and the voltage which is proportional to the predetermined speed limit to thereby vary the vehicle speed level at which the comparison means provides an output. Thus, for example, when the vehicle is idling next to a curb, the relative comparison level is set so that the comparator provides an output when the speed of the vehicle exceeds a coasting level of, for example, 15 miles per hour. When the vehicle exceeds 15 miles per hour, a relay is energized which disconnects the ignition system and the starting switch and in addition energizes a horn. Thus, if some unauthorized person were to attempt to operate the idling vehicle, the motor would not only be immediately turned off but also the horn would be energized to draw attention to the vehicle.
In an alternate embodiment, a pressure sensitive switch is connected to the gear shift level such that when the gear shift is moved from park to reverse or to one of the forward drive positions, the switch would be closed, thereby causing a relay to be energized which disconnects the ignition system and the starter and energizes the vehicle horn.
A key operated switch positioned externally of the operating compartment of the vehicle is closed or activated when the operator leaves the vehicle. Thus, should the hood, trunk, doors or other automotive components be operated which causes conduction of current from the vehicle battery to, for example, a light, a switch associated with these elements will be closed, thereby connecting the vehicle voltage supply to a relay coil. The relay, when energized, disconnects the ignition system and at the same time energizes a horn or other sound generator to signal that the vehicle has been tampered with. This excessive speed and theft deterrent system is compact and inexpensive and requires very little power drain from the battery system until such time as an attempt is made to illegally appropriate the vehicle.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects, features and advantages of the present invention will become more fully apparent from the following detailed description, appended claims and accompanying drawings in which:
FIG. 1 is a schematic drawing of the preferred embodiment of the present invention; and
FIG. 2 is a schematic drawing of an alternate embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Refer now to FIG. 1 where there is disclosed a preferred embodiment of the present invention. The output of a tachometer or any other suitable speed deteching device is coupled to the input terminal 11 of a voltage divider 13. The voltage divider has a plurality of output terminals so that the output voltage of the tachometer can be appropriately sealed. A switch arm 15 selectively makes contact with one of the output terminals of the voltage divider or with an off contact 17. The switch 15 is coupled to the midpoint of resistor 19 which has its respective end terminals coupled to the inputs of a differential amplifier 21. The differential amplifier acts as a comparator and provides an output at output terminals 23 and 25 only when the respective input signals thereto exceed a predetermined voltage. Techniques for operating a differential amplifier as a comparator are well known in the art and therefore will not be discussed in detail herein.
The output at terminal 25 of the differential amplifier 21 is coupled to a first transistor 27 via current supply resistor 29. Transistor 27 is of the PNP type and has its emitter terminal connected to a positive source of voltage, such as, the twelve volt supply of the vehicle battery system. The collector of the transistor is connected to ground via a lamp 28. The collector is also connected to an LC oscillator circuit 31. The output of the oscillator circuit drives a transducer, such as, a speaker or horn 33, so that when transistor 27 is turned on, an audible sound is generated which warns the operator that the vehicle is approaching a predetermined speed limit.
The other output terminal 23 of the comparator 21 is coupled to a second transistor 35 which is also of the PNP type. Transistor 35 has its emitter coupled to a positive voltage supply, such as, the twelve-volt supply of the vehicle battery system. The collector of the transistor is connected to a lamp 37 and to the sound driver arrangement 31 via an isolation diode 39. The isolation diode permits current to be conducted from transistor 35 to the LC oscillator circuit 31 but prevents current from transistor 27 from being conducted to the lamp 37.
The collector of transistor 35 is also connected to a timing circuit 41 via an isolation diode 43. Timing circuit 41 includes an RC circuit comprising resistor 45 and capacitor 47. In addition, the timing circuit 41 includes a gating element which in the preferred embodiment is an unijunction transistor 49. As is well known in the art, unijunction transistors have a gate threshold voltage which is dependent upon the voltage across its output base terminals. Thus, when the voltage across the capacitor 47 rises to a predetermined level, the unijunction transistor 49 is gated on, thereby permitting capacitor 47 to discharge through the transistor and resistor 51 to ground. Once the capacitor has become discharged, the unijunction transistor turns off and capacitor 47 again charges. In the preferred embodiment, the resistor 45 and capacitor 47 are chosen such that for a twelve-volt input to resistor 45 via diode 43 the unijunction transitor will be gated once every ten seconds. It should be understood, however, that the rate at which the oscillator 41 generates output pulses can be suitably varied by appropriately changing the values of the resistor 45 and capacitor 47 or by varying the voltage across the base output terminals 48 and 50 of the unijunction transistor 49. The output of the unijunction transistor 49, which appears across resistor 51, is coupled to an output transistor 53 which is of the NPN type. The collector 53 is coupled to the twelve-volt battery supply of the vehicle via a load resistor 55 and to a suitable counter of conventional design. The counter 57 counts the pulses generated by the oscillator circuit 41 to provide an indication of the total time that an output has been provided on line 23 minus, of course, the initial ten second delay.
In operation, assume for example that switch 15 is in contact with terminal 12 of the voltage divider 13. When the vehicle is traveling well below a present speed limit, such as, 60 miles per hour, the voltage appearing at terminal 12 will not be large enough to generate an output from the differential amplifier-comparator 21 at either terminal 23 of 25. Accordingly, neither of the lamps 28 or 37 are energized. However, as the speed of the vehicle approaches within, for example, five miles per hour of 60 miles per hour, that is, the vehicle is traveling at 55 miles per hour, the differential amplifier-comparator 21 will generate a first negative going output at terminal 25. This output turns on transistor 27 and accordingly, lamp 28 is energized as is the sound driver circuit 31. Thus, an audible tone is generated by speaker 33 to indicate to the driver that the vehicle is approaching a predetermined speed limit.
As the speed of the vehicle further increases to the predetermined speed limit, i.e. 60 miles per hour, output 23 of the differential amplifier-comparator 21 goes in the negative direction thereby turning on transistor 35. With transistor 35 turned on, lamp 37 is energized and the sound driver circuit 31 continues to be energized. At the same time capacitor 47 begins to charge through resistor 45 and diode 43. After the capacitor 47 has charged for ten seconds, the voltage across the capacitor is large enough to gate the unijunction transistor 49 so that the capacitor 47 rapidly discharges through the unijunction transistor and resistor 51 to ground. The gating of the unijunction transistor causes output transistor 53 to be turned on, thereby generating a pulse which is counted in counter 57. After capacitor 47 has discharged, unijunction transistor 49 is turned off and the capacitor again charges for a period of ten seconds. The transistor 49 then discharges, thereby generating a second pulse to be counted by counter 57. The oscillator circuit 41 continues to generate output pulses every ten seconds as long as the speed of the vehicle exceeds the preselected speed level. Accordingly, after an initial ten second delay, the counter 57 provides an indication of the total amount of time that the vehicle has exceeded the preselected speed limit. The initial ten second delay is for the purpose of providing time for the vehicle to temporarily exceed the speed limit in a situation where the vehicle must temporarily move rapidly in order to pass another vehicle on a two-lane highway. Since such a rapid acceleration of the vehicle is in the interest of safety so that the passing lane can be quickly opened again to traffic flowing in the opposite direction, the momentary exceeding of the speed limit is not recorded.
When the switch 15 is connected to the lowest possible setting 14 of the voltage divider 13, the output will be generated at terminal 23 when the speed of the vehicle exceeds a predetermined coasting speed of, for example, fifteen miles per hour. With switch 15 connected to terminal 14, a second switch 16 ganged with switch 15 is connected to contact terminal 18. With switch 16 connected to contact terminal 18, the output of transistor 61 is connected to relay coil 63. Thus, when the output terminal 23 of the comparator 21 provides a signal which turns on transistor 35, the base terminal of transistor 61 receives a positive going signal via isolation diode 62. Since transistor 61 is of the PNP type, when current flows from transistor 35 through diode 62 to biasing resistor 65, the transistor is turned on thereby connecting the battery supply voltage at the collector 67 of the transistor to the relay coil 63 via switch and contact 18. With relay coil 63 energized, switch arms 71, 73 and 75 are rotated to make contact with terminals 72, 74 and 76, respectively. Hence the battery supply 10 is coupled via switch arm 71 and switch contact 72 through isolation 77 to the relay 63 to thereby maintain relay 63 energized even when the speed of the vehicle decreases below the coasting speed limit. At the same time, with switch 71 in contact with terminal 72, the ignition system 79 is disconnected from the battery, thereby preventing the engine from operating. At the same time switch arm 73 is disconnected from the horn energizing circuit and connected to the battery voltage to thereby continuously energize the horn 81. Thus, not only is the engine not operating, but also, the horn is sounding on a continuous basis thereby warning others than an attempt has been made to utilize the vehicle without proper authorization. Finally, the starter system 83, which is normally connected to the vehicle batter supply via an ignition switch 85 is disconnected when the relay 63 is energized, thereby preventing the engine from being started when the vehicle exceeds the coasting speed limit. Once relay 63 has been energized, the system continues in the disabled state until switch arms 71, 73 and 75 are rotated manually back to their original position via an appropriate key.
The system of the present invention also includes a theft prevention arrangement which includes a key operated switch 89. The key actuated switch is positioned on the outside of the car in a convenient position such as on one of the fenders of the vehicle. Thus, when the operator of the vehicle parks the vehicle, the key switch 89 is closed by insertion and rotation of a key in the keyhole positioned on the outside of the vehicle. With switch 89 closed, the theft prevention system is ready for operation. Thus, when one of the doors, the trunk or the hood is opened, a switch associated therewith, designated by the numerals 91, 93 and 95, respectively, is closed, thereby connecting the battery supply of the vehicle to the relay 63. Relay 63 is thereby energized to rotate switches 71, 73 and 75 into contact with terminals 72, 74 and 76, respectively. Thus, the horn is sounded to draw attention to the fact that the vehicle has been tampered with and in addition, the ignition system and starter switch are deactivated, thereby preventing the operation of the car. Should the hood, trunk or doors thereafter be closed, the horn 81 will continue to sound and the ignition and starting system will remain deenergized since the battery supply will remain connected to the relay 63 via isolation diode 77 and switch 71.
Refer now to FIG. 2 where there is disclosed a theft prevention system which operates when the vehicle is not operating. A key operated switch 89 is positioned at some location on a car, such as on one of the fenders of the car, such that when the operator of the vehicle parks the vehicle, the key switch 89 is closed by insertion and rotation of a key in the keyhole. With the switch 89 closed, the theft prevention system is ready for operation.
As an initial condition, a source of power, for example, the vehicle battery 10, is connected across a capacitor 101, a resistor 103 and a series of parallel switches 105. The parallel switches are closed when the door, trunk, hood or other vehicle components are opened. Thus, when one of these components are opened, current flows through capacitor 101 and 103 to cause a sequence of events which will be described hereinbelow. The battery 10 is also connected across resistor 107 and capacitor 109 to thereby establish a positive bias across NPN transistor 111. At the same time, the battery is connected across resistor 113, capacitor 115 and resistor 117 to thereby establish a positive bias at the collector of the NPN transistor 111. Thus, under initial operating conditions, transistor 111 is turned on. The battery is also connected across ten μf capacitor 119 and 100 μf capacitor 121 to thereby establish a voltage division between these two capacitors at the anode of SCR 123. The cathode of the SCR 123 is connected to key switch 89 via normally closed shutoff switch 125. The gate of the SCR 123 is connected to ground via resistor 117 and to one terminal of capacitor 115.
When a door, hood, trunk or other component of the car is operated, switch 105 is closed to thereby connect node 127 to ground via resistor 103. This causes the transistor 111 to turn off to thereby raise the voltage at the collector of transistor 111. This causes current to flow through capacitor 115 and resistor 117 to thereby generate a positive pulse at the gate of SCR 123. SCR 123 is thereby turned on. With SCR 123 turned on, a current flows from the battery 10 through relay coil 129 via SCR 123, normally closed switch 125 and key switch 89 to ground. With relay coil 129 energized, alarm switch 131 is closed to thereby connect the battery to a sound generating alarm, such as, for example, the horn or a siren. Energization of coil 129 also actuates ignition shutoff switch 133 which is connected to the ignition coil such that when closed terminals 4 and 5 the coils are shorted out to prevent the flow of electricity therethrough.
A timing circuit generally designated by the numeral 135 is provided having one terminal 137 connected to the battery supply and the other terminal 139 connected to ground via the SCR switch 123, the normally closed switch 125 and the key switch 89. Thus, when SCR 123 is turned on, current flows from the battery terminal 137 through resistor 141 and capacitor 143 to ground. This causes a positive pulse to appear at the output of the unijunction transistor 145 after a predetermined time period established by the respective values of capacitor 143 and resistor 141. When the positive pulse appears at the output of transistor 145, transistor 147 is turned on to thereby cause current conduction from the battery 10 through relay coil 149, transistor 147 to the SCR 123. With relay coil 149 energized, normally closed switch 125 is opened to thereby interrupt current flow through the SCR 123. Thus, relay coil 129 is deenergized thereby causing switches 131 and 133 to open. At the same time, the timing circuit 135 is deenergized since SCR 123 will be closed or inhibited and the circuit will then return to its normal inoperative condition. The circuit is then automatically set for the next operation which will be caused when both the key 89 is closed and one of the component operating switches 105 is closed.
It should be understood that while the hood, trunk and doors have been described as exemplary elements which generate a theft warning when operated by unauthorized personnel, there can be other elements, such as tires, hub caps, etc., which when tampered with cause a switch 105 to be closed which in turn causes the horn or other sound generating device to be operated so as to warn others that the vehicle has been tampered with by unauthorized personnel.
While the present invention has been disclosed in connection with a preferred embodiment thereof, it should be understood that there may be other obvious variants of the present invention which fall within the spirit and scope of the invention as defined by the appended claims.
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An excessive speed and theft deterrent system wherein a signal is generated having a magnitude which is proportional to the speed of the vehicle. A comparator generates an output signal when the magnitude of the generated signal is greater than a preselected voltage level. In response to the output signal, a pulse train is generated having a predetermined pulse rate wherein the pulse train is counted to thereby indicate a total time in which the vehicle is operated at speeds exceeding a predetermined speed. The system also includes sounding devices for generating a warning signal when a door or the ignition system is operated without authorization.
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This application is a continuation in part of PCT Application 97/02770 designating the United States filed Feb. 21, 1997 claiming the benefit of provisional application 60/011993 filed Feb. 21, 1996. This provisional application is incorporated by reference herein.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
FIELD OF THE INVENTION
The invention relates generally to x-ray equipment and in particular to x-ray equipment providing a compact C-arm system for orthopedic and similar procedures.
BACKGROUND OF THE INVENTION
Portable x-ray fluoroscopy machines provide an x-ray source held in opposition to an electronic image detector, typically on a C-arm, so that x-rays from the x-ray source are received by the image detector. The C-arm may slide through a collar so as to allow it to be rotated to different angles about the patient. Further, the collar may be supported by a pivoting arm providing additional freedom in the positioning of the C-arm.
When the C-arm is correctly positioned, the x-ray source is activated and x-rays pass through the patient to be received by the image detector which provides electronic signals to a video monitor. For larger mobile C-arm systems, the video monitor is typically held on a separate cart or may be suspended from the ceiling on a fixed bracket to be connected to the mobile unit when the mobile unit is in place.
With improvements in electronic hardware and in particular the development of compact image intensifiers and CCD video cameras, it has become possible to build an extremely compact mobile C-arm system. Such systems may make use of increasingly powerful desktop computer technology for image processing and other tasks and may use compact digital printers for producing images. To realize the full benefit of such a compact design, it is desirable that the video monitor be placed with the C-arm on a single integrated structure. It is desirable too that this structure also hold a computer and or printer so that these too can be readily accessible. Ideally, a mobile fluoroscopy unit constructed as a single integrated structure would preserve the user's ability to flexibly position the C-arm at arbitrary angles and positions about the patient, while maintaining access to the integrated video monitor and other equipment, in a compact unit that is lighter and occupies less floor space than previous mobile fluoroscopy systems.
BRIEF SUMMARY OF THE INVENTION
The present invention provides a C-arm fluoroscopy system having a mobile base with a housing that can support on its top, a video monitor providing good visibility for the same, and which has one or more shelves opening to the front for holding ancillary electronic equipment. The C-arm is attached to the housing at a point to the side of the housing below the shelves, allowing the C-arm to extend forward keeping the shelves and monitors positioned for ready access without obstructing them.
Specifically, the present invention provides a mobile fluoroscopy apparatus for use with x-ray diagnostic equipment and comprising a C-arm having an x-ray source and image receptor mounted upon opposing ends to face each other along a beam axis and a collar disposed in slidable engagement with the C-arm so that the C-arm may move in orbital rotation about an orbital axis. A mobile base having a housing with front and sides and moveable along a floor provides a platform on its top supporting a video monitor viewable from the front of the housing, the video monitor receiving image data from the image receptor. The housing may also provide a shelf opening at the front of the housing. An articulating arm assembly comprising an arm pivotally attached at a first end to the collar and pivotally attached at a second end to a side of the cart below the platform allows the C-arm to extend toward the front of the housing without obstructing the video monitor.
Thus it is one object of the invention to provide a simple and highly functional mobile base serving both to support a C-arm and to hold equipment necessary for fluoroscopy imaging in a single unit.
The attachment to the base may allow the arm to rotate about a horizontal axis substantially perpendicular to the extension of the C-arm.
Thus, it is another object of the invention to provide increased articulation in the C-arm support structure without upsetting the balance of a compact mobile base. Rotation about the horizontal axis maintains the angle of the torque with respect to the base support preventing unexpected tipping of the base.
The first end of the arm may be pivotally attached to the collar so that the collar is rotatable relative to the first arm about a second lateral axis of rotation. The arm may include a connecting means providing that the second axis of rotation remaining fixed in angle with respect to the mobile base with pivoting of the second end of the arm with respect to the mobile base.
Thus, it is another object of the invention to minimize unintended movement of the C-arm with motion of the arm such as might adversely or unpredictably affect balance.
The x-ray source may include a heat sink for receiving heat from the x-ray source during operation and the heat sink may conduct heat into the C-arm assembly. Further, the C-arm assembly may position the heat sink at the top of the C-arm during normal use so as to discharge heat away from the image receptor.
It is thus another object of the invention to permit a reduction of size and weight of the C-arm assembly by elimination of the need for auxiliary cooling devices such as pumped oil and by reducing the transfer of heat to the image receptor from the closer x-ray source.
The mobile base may include casters providing wheels rotating about a wheel axis and also pivoting about a substantially vertical castor axis to permit rotation of the apparatus about an arbitrary vertical axis.
Thus, it is another object of the invention to provide an additional degree of freedom of positioning of the C-arm through the use of pivoting casters. One caster may be locked so that a vertical axis is established centered on the lockable caster.
Other objects, advantages, and features of the present invention will become apparent from the following specification when taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
FIG. 1 is a perspective view of the fluoroscopy machine of the present invention showing a C-arm supporting an image intensifier/video camera and x-ray tube in opposition for rotation in a vertical plane, the C-arm held along a mid-line of a cart by an articulated arm attached to the side of the cart;
FIG. 2 is a side view in elevation of the cart of FIG. 1 showing a slide attaching the articulated arm to the side of the cart and showing a four-bar linkage motion of the arm for elevation of the C-arm;
FIG. 3 is a top view of the C-arm system of FIG. 1 with the articulated arm in partial phantom showing the four-bar linkage of the arm for extending the C-arm toward and away from the cart;
FIG. 4 is a detail fragmentary view of an outer pivot of the articulated arm attached to the C-arm such as allows limited pivoting of a plane of rotation of the C-arm about a vertical axis;
FIG. 5 is a detail view of the C-arm of FIG. 1 and the attached x-ray tube assembly showing the electrical cabling providing power to an x-ray tube power supply fitting into a groove in the C-arm and showing an abutment of the anode of the x-ray tube against the metal casting of the C-arm for heat sinking purposes;
FIG. 6 is a schematic block diagram of the fluoroscopy machine of FIG. 1 showing the path of control of a remote x-ray tube power supply by a microprocessor and the receipt of data from the image intensifier/video camera by the microprocessor for image processing;
FIGS. 7 and 8 are simplified images such as may be obtained by the system of FIG. 1 showing portions of the image having moving elements and portions having stationary elements;
FIG. 9 is a flow chart of a method of the present invention providing differently weighted noise reduction to different areas of the image based on motion in the areas of the image;
FIG. 10 is a Fig. similar to that of FIG. 7 showing an image of a rectilinear grid as affected by pincushion distortion in the image intensifier and video camera optics such as may provide a confusing image of a surgical tool being manipulated in real-time;
FIG. 11 is a Fig. similar to FIG. 10 showing equal areas of the image that encompass different areas of the imaged object, such variation as may affect quantitative bone density readings;
FIG. 12 is a plot of raw image data from the image intensifier/video camera as is translated into pixel brightness in the images of FIGS. 7, 8, 10 and 11 by the microprocessor of FIG. 6 according to a non-linear mapping process such as provides noise equilibrium in the images and maximum dynamic range for clinical data;
FIG. 13 is a histogram plotting values of data from the image intensifier/video camera versus the frequency of occurrence of data values showing an isolated Gaussian distribution at the right most side representing unattenuated x-ray values;
FIG. 14 is a flowchart describing the steps taken by the programmed microprocessor of FIG. 6 to identify background pixels and remove them from a calculation exposure rate used for controlling the remote x-ray tube power supply of FIG. 6;
FIG. 15 is a detailed block diagram of the first block of the flow chart of FIG. 14;
FIG. 16 is a first embodiment of the second block of the flow chart of FIG. 14;
FIG. 17 is a second embodiment of the second block of the flow chart of FIG. 14;
FIG. 18 is a detailed flow chart of the third block of the flow chart of FIG. 14;
FIG. 19 is a schematic representation of a distorted image of FIG. 11 and a schematic representation of a corresponding undistorted image showing the variables used in the mathematical transformation of the distorted image to correct for rotation and distortion;
FIG. 20 is a flow chart of the steps performed by the computer in correcting and transforming the image of FIGS. 11 and 19;
FIG. 21 is a perspective view of an occluder placed in an x-ray beam prior to an imaged object and used for calculating scatter;
FIG. 22 is a flow chart of the steps of calculating and removing scatter using the occluder of FIG. 21;
FIG. 23 is a cross-sectional view through the occluder of an imaged object of FIG. 21 along line 23--23, aligned with a graph depicting attenuation of x-rays as a function distance along the line of cross-section as well as theoretical attenuation without scatter and scatter components; and
FIG. 24 is a graphical representation of an adjustment of calculated scatter from the image of FIG. 23 based on normalizing points established by the occluder of FIG. 21.
DETAILED DESCRIPTION OF THE INVENTION
C-arm Support Mechanism
Referring now to FIG. 1, an x-ray machine 10 per the present invention includes a generally box-shaped cart 12 having castors 14 extending downward from its four lower corners. The castors 14 have wheels rotating about a generally horizontal axis, and swiveling about a generally vertical axis passing along the edges of the cart 12. Castors 14, as are understood in the art, may be locked against swiveling and/or against rotation.
With one castor 14 locked and the others free to rotate and swivel, a pivot point 15 for the cart 12 is established with respect to the floor such as may be used as a first positioning axis 11 for the x-ray machine 10.
Positioned on the top of the cart 12 is a turntable 16 holding a video monitor 18 and attached keyboard 20 for swiveling about a vertical axis for convenience of the user. The video monitor 18 and the keyboard 20 may swivel separately so that one operator may view the video monitor 18 while a second operates the keyboard 20.
The video monitor 18 and the keyboard 20 allow for control of a computer 22 contained in a shelf on the cart 12 open from the front of the cart 12. The computer 22 may include a general microprocessor-type processor 23 and a specialized image processor 27 for particular functions as will be described. The computer 22 further includes a number of interface boards allowing it to provide control signals to various components of the x-ray machine 10 as will be described and to receive x-ray image data. In addition, the computer 22 receives signals from a foot switch 61 that is used to activate the x-ray system for a brief exposure. Control of the computer 22 may also be accomplished through a remote control wand 63 of a type known in the art.
Referring now also to FIG. 2, attached to the right side of the cart 12 is a horizontal slide 24 positioned to provide an attachment point 26 for an articulated arm 19 supporting a substantially circular C-arm 56, which in turn holds an x-ray tube 68 and an image intensifier 82 and camera 84, in opposition, and facing each other as will be described below. The function of the x-ray tube, the image intensifier and the camera are well known in the prior art in the use of mobile C-arm type x-ray devices used for image display and are described in U.S. Pat. No. 4,797,907 hereby incorporated by reference as part of the prior art. The C-arm may be mass balanced, that is to say its weight may be distributed to reduce its tendency to rotate through collar 53 so that minimal frictional pressure may be used to prevent it from moving.
The articulated arm 19 may be slid horizontally toward the front of the cart 12 to provide a second positioning axis 25 of the x-ray machine 10. A first pulley 28 is rotatively fixed in a vertical plane, attached to the portion of the slide 24 that may move with respect to the cart 12, and is pivotally attached to a rigid arm 30 extending toward the front of the cart 12. The other end of the rigid arm 30 supporting a second pulley 32 is also mounted to swivel with respect to arm 30. A belt 34 wraps around a portion of the circumference of each of pulleys 28 and 32 and is affixed at one point along that circumference to each of the pulleys 28 and 32 so that pivoting motion of the arm 30 about the center point 26 of pulley 28 causes rotation of pulley 32 so that it maintains a fixed rotational orientation with respect to the cart 12 as pulley 32 and hence C-arm 56 is moved up and down along a third axis 37. The linkage, so created, is a variation of the "four bar linkage" well known in the art.
Helical tension springs (not shown for clarity) balance the pulley 32 in rotative equilibrium about point 26 against the weight of the articulated arm 19, C-arm 56, and other devices attached to the arm 19.
Attached to pulley 32 is a third pulley 36 extending in a generally horizontal plane perpendicular to the plane of pulley 32. The third pulley 32 is attached pivotally to a second rigid arm 40 which at its other end holds another pulley 38 positioned approximately at the midline 41 of the cart 12. The midline 41 symmetrically divides the left and right sides of the cart 12.
Portions of the circumference of pulleys 36 and 38 are also connected together by a belt 44 so as to form a second four bar linkage allowing pulley 38 to move toward and away from the cart 12, along a fourth positioning axis 45, with pulley 38 and C-arm 56 maintaining their rotational orientation with respect to cart 12.
Referring now to FIG. 4, pulley 38 includes a center shaft member 50 having a coaxial outer collar 52 to which belt 44 is attached. A stop 54 attached to the shaft 50 limits the motion of the collar 52 in rotation with respect to the shaft 50 to approximately 26 degrees. Frictional forces between shaft 50 and collar 52 cause shaft 50 to maintain its rotational orientation with respect to collar 52 and hence with respect to pulley 36 until sufficient force is exerted on shaft 50 to displace it with respect to collar 52. Thus pressure on the C-arm 56 can provide some pivoting motion of the C-arm about the axis of the pulley along the fifth positional axis 55.
Referring now to FIGS. 1, 3 and 4, attached to the shaft 50 is a C-arm collar 52 supporting the arcuate C-arm 56 curving through an approximately 180 degree arc in a vertical plane substantially aligned with the midline 41 of the cart 12 as has been mentioned. The shaft 50 may connect to collar 52 so that the latter may swivel in about a horizontal axis bisecting the circle of the C-arm 56. This axis may be aligned with the center of mass of the C-arm 56 so that there is not a self-righting tendency of the C-arm or the axis may be placed above the axis of the C-arm so as to provide for a beneficial self righting action. This motion is orthogonal to that provided by motion of shaft 50 and may augment that provided by the castors 14. Techniques of balancing the C-arm in its various rotational modes, when this is desired, is taught by U.S. Pat. No. 5.038,371 to Janssen issued Aug. 6th, 1991 and hereby incorporated by reference as exemplifying the known prior art understood to all those of ordinary skill in the art.
As described above, motion of the collar 52 may be had in a vertical manner by means of the parallelogram linkage formed by pulleys 28 and 32 of the articulated arm 19 as shown in FIG. 2. Forward and backward motion away from and toward the cart 12 may be had by the second four bar linkage formed from pulleys 36 and 38. A slight pivoting of the C-arm 56 about a vertical axis slightly to the rear of the collar 52 and concentric with the axis of pulley 38 may be had by means of the rotation between collar 52 and 50 of FIG. 4. Greater rotation of the C-arm about the vertical axis passing through pivot point 15 may be had by rotation of the cart about one of its stationary castors 14. Thus, considerable flexibility in positioning the C-arm may be had.
Referring now to FIG. 5, the C-arm 56 is an aluminum casting having formed along its outer circumference a channel 58 into which a cable 60 may be run as will be described. C-arm 56 has a generally rectangular cross-section taken along a line of radius of the C-arm arc. Each corner of that rectangular cross-section holds a hardened steel wire 62 to provide a contact point for corner bearings 64 within the collar 52. The corner bearings 64 support the C-arm 56 but allow movement of the C-arm 56 along its arc through the collar 52.
A cable guide pulley 66 positioned over the channel 58 and having a concave circumference feeds the cable 60 into the channel 58 as the C-arm moves preventing tangling of the cable 60 or its exposure at the upper edge of the C-arm 56 when the C-arm 56 is rotated. She excess length of cable 60 loops out beneath the collar 52.
X-ray Tube Cooling
Referring now to FIGS. 5 and 6, the C-arm supports at one end a generally cylindrical x-ray tube 68 having a cathode 70 emitting a stream of electrons against a fixed anode 72. The conversion efficiencies of x-ray tubes are such that the anode 72 can become quite hot and typically requires cooling. In the present invention, the anode 72 is positioned to be bolted against the aluminum casting of the C-arm 56 thereby dissipating its heat into a large conductive metal structure of the C-arm 56.
The x-ray tube 68 is connected to an x-ray tube power supply 74 which separately controls the current and voltage to the x-ray tube 68 based on signals received from the computer 22 as will be described. The control signals to the x-ray tube power supply 74 are encoded on a fiber optic within the cable 60 to be noise immune. Low voltage conductors are also contained within cable 60 to provide power to the x-ray tube power supply 74 from a low voltage power supply 76 positioned on the cart 12.
During operation, an x-ray beam 80 emitted from the x-ray tube 68 passes through a patient (not shown) and is received by an image intensifier 82 and recorded by a charge couple device ("CCD") camera 84 such as is well known in the art. The camera provides digital radiation values to the computer 22 inversely proportional to the x-ray absorption of the imaged object for processing as will be described below. Each radiation value is dependent on the intensity of x-ray radiation received at a specific point on the imaging surface of the image intensifier 82.
Image Noise Reduction
Referring now to FIGS. 6 and 7, the data collected by the CCD camera 84 may be used to provide an image 86 displayed on video monitor 18. As will be described in more detail below, the CCD camera receiving a light image from the image intensifier 82 at a variety of points, provides data to the computer which maps the data from the CCD camera 84 to a pixel 88 in the image 86. For convenience, the data from the CCD camera 84 will also be termed radiation data reflecting the fact that there is not necessarily a one-to-one correspondence between data detected by the CCD camera 84 and pixels 88 displayed on the video monitor 18.
The CCD camera 84 provides a complete set of radiation data for an entire image 86 (a frame) periodically once every "frame interval" so that real-time image of a patient placed within the x-ray beam 80 may be obtained. Typical frame rates are in the order of thirty frames per second or thirty complete readouts of the CCD detector area to the computer 22 each second.
Each frame of data is stored in the memory of the computer 22 and held until after complete storage of the next frame of data. The memory of the computer 22 also holds an average frame of data which represents an historical averaging of frames of data as will now be described and which is normally used to generate the image on the video monitor 18.
In a typical image 86, there will be some stationary object 90 such as bone and some moving object 92 such as a surgical instrument such as a catheter. In a second image 86' taken one frame after the image 86, the bone 90 remains in the same place relative to the edge of the image 86 and 86', however the surgical instrument 92 has moved. Accordingly, some pixels 88' show no appreciable change between images 86 and 86', whereas some other pixels 88" show a significant change between images 86 and images 86'.
Referring now to FIG. 9, as data arrives at the computer 22, the computer 22 executes a stored program to compare current pixels of the image 86' to the last pixels obtained from image 86 as indicated by process block 94. This comparison is on a pixel by pixel basis with only corresponding pixels in the images 86 and 86' compared. The difference between the values of the pixels 88, reflecting a difference in the amount of x-ray flux received at the CCD camera 84, is mapped to a weight between zero and one, with greater difference between pixels 88 in these two images corresponding to larger values of this weight w. This mapping to the weighting is shown at process block 96.
Thus pixels 88", whose value changes almost by the entire range of pixel values between images 86 and 86', receive a weighting of "one" whereas pixels 88' which have no change between images 86 and 86' receive a value of zero. The majority of pixels 88 being neither unchanged nor radically changed will receive a value somewhere between zero and one.
Generally, because the amount of x-ray fluence in the beam 80 is maintained at a low level to reduce the dose to the patient, the images 86 and 86' will have appreciable noise represented as a speckling in the images 86 and 86'. This noise, being of random character, may be reduced by averaging data for each pixel 88 over a number of frames of acquisition effectively increasing the amount of x-ray contributing to the image of that pixel.
Nevertheless, this averaging process tends to obscure motion such as exhibited by the surgical instrument 92. Accordingly, the present invention develops an average image combining the values of the pixels acquired in each frame 86, 86' in which those pixels in the current image 86' which exhibit very little change between images 86 and 86' contribute equally to the average image, but those pixels in the current image 86' that exhibit a great degree of change between images 86 and 86' are given a substantially greater weight in the average image. In this process, a compromise is reached between using historical data to reduce noise and using current data so that the image accurately reflects changes. Specifically, the value of each pixel displayed in the image is computed as follows.
P.sub.i =(1-w)P.sub.i-1 +wP.sub.i,t (1)
where P i-1 is a pixel in the previous average image, w is the weighting factor described above and P i ,t is the current data obtained from the CCD camera 84. This effective merger of the new data and the old data keyed to the change in the data is shown at process block 98.
Image Intensifier Distortion
Referring now to FIG. 10, an image 86" of a rectilinear grid 100 positioned in the x-ray beam 80 will appear to have a barrel or pincushion shape caused by distortion of the image intensifier 82 and the optics of the CCD camera 84. During a real-time use of the image 86" by a physician, this distortion may cause confusion by the physician controlling a tool 102. For example, tool 102 may be a straight wire shown by the dotted line, but may display an image 86' as a curved wire whose curvature changes depending on the position of the tool 102 within the image 86. This distortion thus may provide an obstacle to a physician attempting to accurately place the tool 102 with respect to an object within the image 86'.
Referring now to FIG. 11, the distortion of image 86" also means that two equal area regions of interest 105 (equal in area with respect to the image) do not encompass equal areas of the x-ray beam 80 received by the image intensifier 82. Accordingly, if the data from the CCD camera 84 is used for quantitative purposes, for example to deduce bone density, this distortion will cause an erroneous variation in bone density unrelated to the object being measured.
Accordingly, the present inventors have adopted a real-time digital re-mapping of radiation data from the CCD camera 84 to the image 86 to correct for any pincushion-type distortion. This remapping requires the imaging of the rectilinear grid 100 and an interpolation of the position of the radiation data received from the CCD camera 84 to new locations on the image 86" according to that test image. By using digital processing techniques in a dedicated image processor 27, this remapping may be done on a real-time basis with good accuracy.
Referring to FIG. 19, there are two types of distortion, isotropic and anisotropic. Isotropic distortion is rotationally symmetric (e.g. like barrel and pin cushion distortion). Anisotropic distortion is not rotationally symmetric. Both types of distortion and rotation are so-called third order aberrations which can be written in the form:
Δx=r.sup.2 (Du-dv) (2)
Δy=r.sup.2 (Dv-du) (3)
where Δx and Δy are pixel shifts due to distortion: r is the distance from the correct position to the optical axis and D and d are distortion coefficients which are constant and u and v are correct pixel positions.
Referring also FIG. 2, received image 86 may exhibit pin cushion distortion evident if an image 86 of the rectilinear grid 100 is made. The distortion is caused by the pixel shifts described above.
Equations 1 and 2 may be rewritten as third order two-dimensional polynomials, the case for equation (1) following:
x=(a.sub.x +e.sub.x v+i.sub.x v.sup.2 +m.sub.x v.sup.3)+(b.sub.x +f.sub.x v+j.sub.x v.sup.2 +n.sub.x v.sup.3)u+(c.sub.x +g.sub.x v+k.sub.x v.sup.2 +o.sub.x v.sup.3)u.sup.2 +(d.sub.x +h.sub.x v+l.sub.x v.sup.2 +p.sub.x v.sup.3)u.sup.3 (4)
In these polynomials, a x and a y govern the x and y translation of the image, e x and b y take care of scaling the output image, while e y and b x enable the output image to rotate. The remaining higher order terms generate perspective, sheer and higher order distortion transformations as will be understood to those of ordinary skill in the art. Thirty-two parameters are required for the two, third order polynomials. These parameters may be extracted by a program executed by the computer in an off-line (non-imaging) mode after imaging the known grid 100 and comparing the distorted image of the grid 100 to the known grid 100 to deduce the degrees of distortion.
Referring now to FIG. 19 in a first step of the correction process, the grid 100 is imaged as indicated by process block 160 to determine the exact type of distortion present and to obtain values for the coefficients a through p of the above referenced polynomial equations.
At process block 166, these parameters may be input to the computer 22 and used at a transformation of received image 86 into image data 164 as indicated by process block 168. For rotation of the image 164, new parameters of the polynomials may be entered by means of hand-held remote control wand 63 shown in FIG. 1.
The transformation process generally requires a determination of the pixel shift for each radiation pixel 163 of the input image 86 which in turn requires an evaluation of the polynomials whose coefficients have been input. A number of techniques are known to evaluate such polynomials including a forward differencing technique or other techniques known in the art. These transformations provide values of u and v for an image pixel 170 corresponding to a particular radiation pixel 163.
After the transformation of process block 168. the u, v locations of the radiation pixels will not necessarily be centered at a pixel location defined by the hardware of the video monitor 18 which usually spaces pixels 170 at equal distances along a Cartesian axis. Accordingly, the transformed pixels must be interpolated to actual pixel locations as indicated by process block 172.
A number of interpolation techniques are well known including bilateral and closest neighbor interpolation, however in the preferred embodiment, a high resolution cubic spline function is used. A given value of an interpolated pixel 170 (P int ) is deduced from a 4×4 block of transform pixels (P i ,j) in which it is centered as follows:
P.sub.int =f(n-2)X.sub.1 +f(n-1)X.sub.2 +f(n)X.sub.3 +f(n+1)X.sub.4(5)
where:
X.sub.i =f(m-2)P.sub.i,1 +f(m-1)P.sub.i,2 +f(m)P.sub.i,3 +f(m+1)P.sub.i,4(6)
where:
f(x)=(a+2)x.sup.3 +-(a+3)x.sup.2 +1 for xε[0,1];
f(x)=ax.sup.3 +-5ax.sup.2 +8ax-4a for xε[1,2]; (7)
f(x) is symmetrical about zero. In the preferred embodiment a=-0.5
and where m and n are fractions indicating the displacement of the neighboring pixels P i ,j with respect to P int in the x and y directions, respectively.
At process block 180, the transformed and interpolated image is displayed.
Noise Equalization
Referring now to FIG. 12, the radiation data from the CCD camera 84 are mapped to the brightness of the pixels of the image 86 according to a second transformation. In the preferred embodiment, this mapping between CCD radiation data and image pixel brightness follows a nonlinear curve 103 based on the hyperbolic tangent and being asymptotically increasing to the maximum CCD pixel value. This curve is selected from a number of possibilities so that equally wide bands of image pixel brightness 104 and 106 have equal amounts of image noise. The curve 103 is further positioned to provide the maximum contrast between clinically significant tissues in the image.
Exposure Control
The noise in the image 86 is further reduced by controlling the fluence of the x-ray beam 80 as a function of the density of tissue of the patient within the beam 80. This density is deduced from the image 86 itself produced by the CCD camera 84. In response to the image data, a control signal is sent via the fiber optic strand within the cable 60 to the x-ray tube power supply 74 positioned adjacent to the x-ray tube 68 (shown in FIG. 5). By positioning the x-ray tube power supply 74 near the x-ray tube 68, extremely rapid changes in the power supplied to the x-ray tube 68 may be obtained. Distributed capacitances along high tension cables connecting the x-ray tube 68 to a stationary x-ray tube power supply are thus avoided in favor of low voltage cable 60, and the shielding and inflexibility problems with such high tension cables are also avoided.
Automatic Technique Control
Referring now to FIGS. 13 and 14, a determination of the proper control signal to send to the x-ray tube power supply 74 begins by analyzing the image data 86 as shown in process block 120. The goal is to provide for proper exposure of an arbitrary object placed within the x-ray beam 80 even if it does not fill the field of view of the CCD camera 84. For this reason, it is necessary to eliminate consideration of the data from the CCD camera 84 that form pixels in the image corresponding to x-rays that bypass the imaged object and are unattenuated ("background pixels"). These background pixels may be arbitrarily distributed in the image 86 and therefore, this identification process identifies these pixels based on their value. To do this, the computer 22 collects the values of the pixels from the CCD camera 84 in a histogram 122 where the pixels are binned according to their values to create a multiple peaked plot. The horizontal axis of the histogram 122 may for example be from 0 to 255 representing 8 bits of gray scale radiation data and the vertical axis may be a number of pixels having a particular value.
If there is a histogram value at horizontal value 255, and the maximum gray scale exposure recorded, the entire area of the histogram 122 is assumed to represent the imaged object only (no background pixels). Such a situation represents an image of raw radiation only or a high dose image of a thin object with possible clipping. In assuming that the whole histogram 122 may be used to calculate technique without removal of background pixels, a reduced exposure rate will result as will be understood from the following description and the peak classification process, to now be described, is skipped.
Otherwise, if there are no pixels with the maximum value of 225, the present invention identifies one peak 124 in the histogram 122 as background pixels indicated by process block 120 in FIG. 14. In identifying this peak 124, the computer 22 examines the histogram 122 from the brightest pixels (rightmost) to the darkest pixels (leftmost) assuming that the brightest pixels are more likely to be the unattenuated background pixels. The process block 120 uses several predetermined user settings as will be described below to correctly identify the peak 124.
Once the peak 124 has been identified, the pixels associated with that peak are removed per process block 126 by thresholding or subtraction. In the thresholding process, pixels above a threshold value 138 below the peak 124 are considered to be background pixels and are omitted from an exposure rate calculation. In the subtraction method, the peak 124 itself is used as a template to identify pixels which will be removed.
At process block 128, an exposure rate is calculated based on the values of the pixels in the remaining histogram data and at process block 130, an amperage and voltage value are transmitted via the cable 60 to the x-ray tube power supply and used to change the power to the x-ray tube. Generally, if the exposure rate is above a predetermined value, the amperage and voltage are adjusted to cut the x-ray emission from the x-ray tube, whereas if the exposure rate is below the predetermined value, the amperage and voltage are adjusted to boost the exposure rate to the predetermined value.
Referring now to FIGS. 13, 14 and 15, the process of identifying background pixels will be explained in more detail. Process block 120 includes as a first step, an identification of a right most peak 124 in the histogram 122 (shown in FIG. 13) as indicated by subprocess block 132.
At succeeding subprocess block 134, this right most peak 124 is compared against three empirically derived parameters indicated in the following Table 1:
TABLE 1______________________________________Minimum Slope Range Minimum necessary pixel range for(MSR) which the slope of the peak must be monitonically increasing.Histogram Noise Level Minimum height of the maximum(HNL) value of the peak.Maximum Raw Radiation Width Maximum width of the detected peak(MRRW) with respect to the width of the entire histogram.______________________________________
Specifically at subprocess block 134, each identified peak 124 is tested against the three parameters indicated in Table 1. In the description in Table 1, "width" refers to the horizontal axis of the histogram 122 and hence a range of pixel values, whereas "height" refers to a frequency of occurrence for pixels within that range, i.e., the vertical axis of the histogram 122.
These first two tests, MSR and HNL, are intended to prevent noise peaks and peaks caused by bad imaging elements in the CCD camera 84 or quantization of the video signal in the A to D conversion from being interpreted as background pixels.
Peaks 124 with a suitable stretch of monotonically increasing slope 131 (shown in FIG. 13) according to the MSR value and that surpass the histogram noise level HNL 133 are evaluated against the MRRW parameter. This third evaluation compares the width 135 of the histogram 122 against the width of the entire histogram 122. The MRRW value is intended to detect situations where the imaged object completely fills the imaging field and hence there are no unattenuated x-ray beams or background pixels being detected. A valid peak 124 will normally have a width 135 more than 33% of the total width of the histogram 122.
At decision block 136 if the peak 124 passes the above tests, the program proceeds to process block 126 as indicated in FIG. 14. Otherwise, the program branches back to process block 132 and the next peak to the left is examined against the tests of process block 134 until a passing peak is found or no peak is found. If no peak is found, it is assumed that there are no background pixels and a raw exposure value is calculated from all pixels as described above.
Assuming that a peak 124 passes the tests of Table 1, then at process block 126 background pixels identified by the peak 124 selected at process block 120 are eliminated.
In a first method of eliminating background pixels indicated at FIG. 16, a magnitude threshold 138 within the histogram 122 is identified. Pixels having values above this threshold will be ignored for the purpose of selecting an exposure technique. The threshold 138 is established by identifying the center 140 of the peak 124 (its maximum value) and subtracting from the value of the center a value a being the distance between the start of the peak 124 as one moves leftward and the maximum 140. The area under the histogram 122 for values lower than the threshold 138 is computed to deduce a raw exposure value which will be used as described below.
In a second embodiment, the shape of the histogram peak 124 from the start of the peak as one moves leftward to its maximum 140 is reflected about a vertical line passing through the maximum 140 and subtracted from the histogram peak 124 to the left of the vertical line. This approach assumes that the peak 124 of the background pixels is symmetrical and thus this method better accommodates some overlap between the object pixels and the background pixels in the histogram 122. Again, the remaining pixels of the histogram 122 are summed (by integration of the area under the histogram 122 minus the area of the peak 124 as generated by the reflection) to provide a raw exposure value.
Referring now to FIG. 18, the raw exposure value is transformed by the known transfer characteristics of the CCD camera (relating actual x-ray dose to pixel value) to produce a calculated current exposure rate as indicated at process block 144.
Referring to process block 146, the current exposure rate is next compared to a reference exposure rate, in the preferred embodiment being 1.0 μR per frame, however this value may be refined after further clinical testing. If at process block 148, the current exposure rate is within a "half fine-tune range" of the reference exposure rate, then the program proceeds to process block 150, a fine tuning process block, and the amperage provided to the x-ray tube are adjusted in accordance to the disparity between the amperage and reference exposure rate. That is, if the current exposure is greater than the reference exposure rate, the amperage to the x-ray tube is reduced. The new value of amperage is compared against a predetermined range of amperage values (maximum beam current and minimum beam current values) so that the amperage value may never vary outside of this range.
If at decision block 148, the current exposure rate is outside of the half fine tune range established at decision block 148, a more substantial adjustment process is undertaken. Generally, the exposure provided by an x-ray system will follow the following equation:
X≈s·mA·kVp.sup.n. (8)
where:
s is seconds,
mA is the amperage provided to the x-ray tube,
kVp is the voltage provided to the x-ray tube, and
n is a power factor dependent on the geometry of the machine and the particular kind of object being imaged.
Generally, the value of n will not be known in advance. Accordingly in the more substantial correction process, n is deduced by obtaining two different exposures for equal predetermined intervals with different kVp values so that the value of n may be deduced.
At decision block 152. it is determined whether a first or second reference exposure is to be obtained. If the first reference exposure was just obtained, the program proceeds to process block 154 and a new value of kVp is determined for a second exposure. In this case, the first exposure used will be that which was employed to produce the histogram 122 as previously described.
If the comparison of process block 148 indicated that the exposure rate was too high, a lower kVp value is selected; and conversely, if the exposure at process block 148 indicated the exposure was too low, an increased value of kVp is provided. The new kVp value for the second exposure must be within a predetermined range of kVp values established by the user. Mathematically, the kVp value selected may be described as:
kVp.sub.2 =kVp.sub.1 +a(dkVp) (9)
where a is a step factor and
dkVp is a minimum practical change in tube voltage.
Two preferred means of selecting may be used: one providing linear and one providing logarithmic scaling. Such scaling techniques are well understood to those of ordinary skill in the art.
If at decision block 152, a second frame has already been taken with the new voltage value, then the program proceeds to process block 156 and the value of n in equation (9) is calculated. If the value of amperage is held constant between the first and second frame, the value of n may be determined according to the following equation: ##EQU1## where X 1 and X 2 are the measured exposure rates at the first and second frames, respectively and
kVp 1 and kVp 2 are the two x-ray tube voltages during the first and second frames.
At process block 158, this value of `n` is checked against threshold values intended to detect whether an erroneous value of n has been produced as a result of `clipping` in the radiation data used to calculate exposure. As is understood in the art, clipping occurs when an increased dose of an element of the CCD camera produces no increase in the camera's output.
At decision block 158, if the value of n calculated at process block 156 is greater than or equal to one, it is assumed to be valid and the program proceeds to process block 160 where kVp and mA are adjusted by setting mA equal to a maximum reference value and calculating kVp according to the following equation: ##EQU2## where kVp new and mA new are the settings for the next frame to be shot.
If the resulting kVp value conflicts with the minimum system, kVp, kVp is set to the minimum system value and mA is calculated according to the following equation using the mA and kVp value of the second frame. ##EQU3##
If the value of n in decision block 158 is less than one. then at process block 162, n is tested to see if it is less than zero. This value of n is realized when the exposure rate of the second frame changes in the opposite direction of the tube voltage. This suggests a clipped histogram and therefore the program branches back to process block 154 to obtain a new second frame. This condition may also arrive from object motion between the first and second frame.
On the other hand, if at decision block 162, n is not less than zero (e.g. n is between zero and 1), the program proceeds to process block 166. Here it is assumed that because the sensitivity of the exposure rate on change in kVp is low, there may be some partial clipping. New values of kVp and mA are then computed and used with the previous second frame values to calculate a new n as follows. Generally, if kVp and mA are high, they are both lowered and if kVp and mA are low, they are both raised.
Scatter Reduction
Referring now to FIG. 1, the image produced by the present invention may be used for quantitative analysis including, for example, that of making a bone density measurement. It is known to make bone density analyses from x-ray images through the use of dual energy techniques in which the voltage across the x-ray tube is changed or a filter is periodically placed within the x-ray beam to change the spectrum of the x-ray energy between two images. The two images may be mathematically processed to yield information about different basis materials within the image object (e.g. bone and soft tissue). For these quantitative measurements, it is desirable to eliminate the effect of scatter.
Referring now to FIG. 23 in imaging a patient's spine 200, for example, x-rays 202 are directed from an x-ray source 201 through the patient 199 to pass through soft tissue 204 surrounding a spine 200. Certain of the x-rays 202 are blocked by the spine 200 and others pass through the spine 200 to be recorded at the image intensifier 206. An attenuation image 208 measured by an image intensifier measures those x-rays passing through the patient 109.
A portion 210 of the attenuation image directly beneath the spine 200 records not only those x-rays 202 passing through the spine 200 and the soft tissue 204 above and below it, but also scattered x-rays 212 directed, for example, through soft tissue 204 to the side of the spine 200 but then scattered by the soft tissue to proceed at an angle to the portion 210 of the attenuation image 208 beneath the spine 200. Because the scattered x-rays 212 do not carry information about the attenuation of the spine 200, they are desirably removed from the image 208 prior to its use in quantitative measurement.
For this purpose, the present invention uses an occluder 214 being an x-ray transparent plate such as may be constructed of Plexiglas and incorporating into its body, a plurality of x-ray blocking lead pins 216. Preferably these pins are placed so as to project images 218 onto the image 208 received by the image intensifier 206 in positions outside an image 220 of the spine 200. Generally therefore, the pins 216 are placed at the periphery of the occluder 214. The pins 216 are sized so as to substantially block all direct x-rays from passing through them but so that their images 218 include a significant portion of scattered x-rays 212.
Referring now to FIG. 22 at a first step of a scatter reduction operation with the occluder 214 of FIG. 21, an image is acquired of the imaged object, for example, the spine 200 and its surrounding soft tissue 204 (not shown in FIG. 21) including the images 218 of the pins 216. This acquisition is indicated by process block 221 of FIG. 22.
The pins 216 are held in predetermined locations with respect to the image 208 so that their images 218 may be readily and automatically identified. Preferably the pins 216 are placed at the interstices of a Cartesian grid, however, other regular patterns may be chosen. The image 208 may be corrected for pincushion type distortion, as described above, so that the locations of the pins 216 may be readily located in the image based on their known positions in the occluder 214.
At each pin image 218, a value 222 indicating the magnitude of the received x-rays, shown in FIG. 23, may be ascertained. This value 222 measures the scatter received in the vicinity of image 218 caused generally by the effect of the soft tissue 204 and possible secondary scatter effects in the image intensifier 206. Values 222 are recorded, as indicated by process block 224, for each pin image 218. From these values, a set of normalizing points are established.
The image 208 is then used to derive a scatter map. Referring to FIG. 23, generally the amount of scatter at a given point will be a function of how many x-ray photons are received at points adjacent to the given point. For example, comparing the image 208 to a theoretical scatterless image 228 generally in an attenuated region 230 of the image 208 (e.g., under the spine 200), scatter will increase the apparent value in the image 208 as a result of radiation from nearby low attenuation regions scattering into the high attenuation region 230. Conversely the apparent value at a low attenuation region 232 will be decreased because of the scatter into the high attenuation region.
A map of the scattered radiation may thus be modeled by "blurring" the image 208. This blurring can be accomplished by a low pass filtering of the image 208, i.e., convolving the image 208 with a convolution kernel having rectangular dimensions corresponding to the desired low pass frequency cut off. The effect is an averaging of the image 208 producing scatter map 234.
The image used to produce the scatter map 234 is an attenuation image 208 10 obtained from the patient 199 without the occluder 214 in place, or may be an image 208 including the images 218 of the pins 216 but with the latter images 218 removed based on knowledge of their location. This removal of images 218 may substitute values of the image 208 at points 239 on either side of the images 218. The process of driving the scatter map from the image is indicated by process block 235 of FIG. 24.
Next as indicated by process block 237, the scatter map 234 is fit to the normalizing points 222 previously determined at process block 224.
Referring to FIG. 24, the scatter map 234 is thus normalized so that the portions 238 of the scatter map 236 located near the places where the images 218 would fall are given values 222 as determined at process block 224. This involves a simple shifting up or down of the scatter map 236 and may employ a "least square" fit to shift the scatter map 236 to multiple values 222 obtained from each pin 216. As adjusted, the scatter map 236 is then subtracted from the image 208 to eliminate or reduce the scatter in that image as indicated by process block 239.
The effect of subtracting a low pass filtered or blurred image properly normalized to actual scatter is to sharpen up the image 208 but also to preserve its quantitative accuracy. Thus the present invention differs from prior art scatter reduction techniques in that it both addresses the variation in scatter across the image caused by attenuation of x-rays by the imaged object but also incorporates accurate measurements of scatter in certain portions of the image.
It is thus envisioned that the present invention is subject to many modifications which will become apparent to those of ordinary skill in the art. Accordingly, it is intended that the present invention not be limited to the particular embodiment illustrated herein, but embraces such modified forms thereof as come within the scope of the following claims.
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A compact mobile x-ray C-arm system employs a cart supporting a video monitor on a top shelf and other imaging equipment on lower shelves opening from the front of the cart. The C-arm is supported by a pivot attached to the side of the cart below the platform allowing the C-arm to extend forward without obstructing the shelves or video monitor and yet providing for a balanced operation permitting a smaller footprint area of the cart. Use of the C-arm as a heat sink for the x-ray source and swiveling casters to allow an additional axis of rotation allow a more compact structure to be produced.
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CROSS-REFERENCE
This is a division of Ser. No. 198,280 filed Oct. 17, 1980, now U.S. Pat. No. 4,391,815, which is a continuation of Ser. No. 079,560 filed Sept. 27, 1979, now abandoned, and Ser. No. 117,261 filed Jan. 31, 1980, now abandoned, which is a divisional of Ser. No. 970,199 filed Dec. 18, 1978, now abandoned, which is a continuation of Ser. No. 776,976 filed Mar. 14, 1977, now abandoned.
DETAILED DESCRIPTION
This invention relates to cyano substituted benzo[b]pyrans which are useful as intermediates and in the treatment of hypertension.
Accordingly the present invention provides cyanobenzo[b]pyrans of the formula (I): ##STR1## and the pharmaceutically acceptable acid addition salts thereof, wherein NR 1 R 2 is alkylamino of 1 to 4 carbon atoms, pyrrolidino or piperidino and R is hydrogen, alkyl of 1 to 3 carbon atoms, alkanoyl of up to 8 carbon atoms or benzoyl.
As illustrated in the formula (I), the --N(R 1 )(R 2 ) and --OR moieties are trans.
Examples of such cyano compounds of Formula (I) include:
trans-2,2-dimethyl-4-piperidino-6-cyano-3,4-dihydro-2H-benzo[b]pyran-3-ol, and its hydrochloric salt;
trans-2,2-dimethyl-4-pyrrolidino-6-cyano-3,4-dihydro-2H-benzo[b]pyran-3-ol, and its hydrochloric salt;
trans-2,2-dimethyl-4-isopropylamino-6-cyano-3,4-dihydro-2H-benzo[b]pyran-3-ol, and its hydrochloric salt;
trans-2,2-dimethyl-3-methoxy-4-pyrrolidino-6-cyano-3,4-dihydro-2H-benzo[b]pyran; and
trans-2,2-dimethyl-3-(2,2-dimethylpropanoyloxy)-4-pyrrolidino-6-cyano-3,4-dihydro-2H-benzo[b]pyran.
The compounds of the Formula I have excellent vasodilatory activity. In particular the compounds demonstrate a favorable therapeutic ratio; i.e., the separation of desired vasodilatory effects from undesired cardiac effects.
R can be hydrogen, methyl, ethyl, n-propyl or isopropyl, of which methyl is preferred. R can also be an unsubstituted carboxylic acyl group such as acetyl or propionyl, or benzoyl. Preferably R is a hydrogen atom. Moreover the cyano group is preferably in the 6-position.
It will be appreciated that the depicted trans isomer can exist in the form of a mixture of stereoisomers or as a single stereoisomer. It is particularly convenient to prepare the compounds as racemic mixtures. Most of the desired biological activity is found in the (+)-isomer of the compound wherein R is hydrogen and in the derivatives thereof wherein R is alkyl or acyl. Thus in a preferred aspect this invention provides such (+)-isomer. Racemic mixtures can be separated into pure optical isomers using such techniques as fractional crystallization of salts with optically acitve acids.
Suitable acid addition salts of the compounds of the Formula I are those with pharmaceutically acceptable inorganic or organic acids such a hydrochloric, hydrobromic, phosphoric, sulphuric, methanesulphonic, toluenesulphonic, acetic, propionic, succinic, citric, tartaric, mandelic, lactic, gluconic or the like acid.
The compositions of this invention are most suitably adapted for oral administration, although other modes of administration such as by injection, for example by intravenous injection for heart failure, are also suitable.
In order to obtain consistency of administration it is preferred that the compositions of this invention are in the form of a unit-dose. Suitable unit dose forms include tablets, capsules and other powders in sachets or vials. Unit dose forms generally will contain from 1 to 100 mg of the compound and more usually from 2 to 50 mg, for example 5 to 25 mg; e.g., 6, 10, 15 or 20 mg. Such compositions may be administered from 1 to 6 times a day, more usually from 2 to 4 times a day, in a manner such that the daily dose is from 5 to 200 mg for a 70 kg human adult and more commonly from 10 to 100 mg.
Shaped oral dosage compositions are favored composition aspects.
In addition such compositions may contain further active agents such as other anti-hypertensive agents, diuretics and β-blocking agents. β-blocking agents are particularly suitable for inclusion in the compositions of this invention. For example, propanolol may be included in conventionally used quantities.
The compositions of this invention are formulated in conventional fashion, as for example in a manner similar to that used for known antihypertensive agents such as hydrallazine.
Oral dosage forms may contain such conventional agents as fillers (diluents), lubricants, binders, disintegrants, colourants flavourings, surface active agents, preservatives, buffering agents and the like. Typical fillers include microcrystalline cellulose, manitol, lactose and other similar agents. Suitable disintegrants include starch, polyvinylpyrrolidone and starch derivatives such as sodium starch glycollate and the like. Typical lubricants include stearic acid, magnesium stearate, magnesium lauryl sulphate and similar agents. The oral compositions can be prepared by conventional methods of blending, filling, tabletting and the like. Repeated blending operations can be used to distribute the active ingredient throughout those compositions containing large quantities of fillers, as is conventional.
Oral compositions normally will be used in the treatment of chronic hypertension rather than acute. For emergency use, for example in heart failure cases, intravenous administration may be indicated. Intravenously administrable sterile solutions in water for injection can be made up from the sterile composition in a vial in accordance with conventional practice.
The hypotensive activity of the compounds of the present invention can be conveniently observed in conventional animal models, of which the following is representative:
Systolic blood pressures are determined by a modification of the tail cuff method described by Claxton et al., European Journal of Pharmacology, 37, 179 (1976). An oscilloscope (or W+W BP recorder, model 8002) can be used to display pulses. Prior to all measurements rats are placed in a heated environment (33.5±0.5° C.) before transfer to a restraining cage. Each determination of blood pressure is the mean of at least 6 readings.
Typical results are as follows [in which due to animal availability spontaneously hypertensive rats (ages 12-18 weeks, systolic blood pressures >170 mm Hg) were used in the Compound A tests, and DOCA-salt treated hypertensive rats were used in the Compound B and C tests]:
TABLE I__________________________________________________________________________Dose Initial % Change in Initialmg/kg No. of B.P. B.P. (Systolic) HeartCompound p.o. Animals mm Hg 1 hr. 2 hr. 4 hr. 6 hr. 24 hr. Rate__________________________________________________________________________A 1 5 208 ± 3 -22 ± 2 -21 ± 2 -29 ± 2 -21 ± 2 -18 ± 2 471 ± 11A 0.3 6 197 ± 2 -21 ± 2 -12 ± 2 -8 ± 2 -2 ± 2 +6 ± 4 477 ± 5B 1 5 185 ± 88 -3 ± 3 -4 ± 3 -5 ± 3 -1 ± 2 +9 ± 1 344 ± 17C 1 6 191 ± 4 -37 ± 2 -27 ± 3 -23 ± 4 -14 ± 3 +4 ± 3 331 ± 13__________________________________________________________________________ % Change in Heart Rate Compound 1 hr. 2 hr. 4 hr. 6 hr. 24 hr.__________________________________________________________________________ A +10 ± 3 +8 ± 2 +7 ± 2 +7 ± 2 -4 ± 4 A +2 ± 1 -8 ± 2 -6 ± 1 -4 ± 1 -4 ± 4 B +16 ± 7 +10 ± 7 +2 ± 6 +2 ± 2 +17 ± 6 C +22 ± 3 +17 ± 5 +7 ± 6 +13 ± 4 +9 ± 3__________________________________________________________________________
The compounds identified as A, B and C are as follows:
A=trans-2,2-dimethyl-4-pyrrolidino-6-cyano-3,4-dihydro-2H-benzo[b]pyran-3-ol HCl.
B=(-)-trans-2,2-dimethyl-4-pyrrolidino-6-cyano-3,4-dihydro-2H-benzo[b]pyran-3-ol HCl.
C=(+)-trans-2,2-dimethyl-4-pyrrolidino-3,4-dihydro-2H-benzo[b]pyran-3-ol HCl.
The compounds of the invention can be prepared by allowing a compound of the formula (II): ##STR2## to react with an amine of the formula H--N(R 1 )(R 2 ) to produce a compound of the Formula I wherein R is hydrogen. The reaction can be carried out at any non-extreme low, medium or high temperature, as for example from -10° C. to 200° C. In general ambient or slightly elevated temperatures are most suitable, as for example, 12° to 100° C. The reaction is normally carried out in a solvent such as a lower alcohol or lower ketone, as for example methanol, ethanol, propanol, acetone or methylethylketone. It has been found that the reaction proceeds smoothly if carried out in refluxing ethanol. The compound of the formula II can be prepared in situ, for example from a corresponding bromohydrin.
The product, which is the trans form, can be obtained from the reaction mixture by removal of the solvent, normally accomplished by evaporation under reduced pressure. The initial product may contain some epoxide, which can be separated by dissolving the reaction product in ethyl acetate and extracting with dilute acid. If desired the solvent may be evaporated at this stage but it is usually more convenient to render the mixture basic, back extract with ethyl acetate and recover by evaporation at reduced pressure. If a salt is desired, this product which is the free base may be dissolved in diethyl ether containing a little ethanol and treated with a solution of the acid, for example in diethyl ether. The desired salt can then be collected by filtration.
Etherification of the initially produced compound can be (R═hydrogen) effected in a conventional manner, as for example the reaction with alkyl iodide in the presence of a base such as potassium tert-butoxide in an inert solvent such as toluene.
Preparation of esters (R═alkanoyl or benzoyl) can be effected by conventional methods of esterification such as the reaction with an acylating agent, optionally in the presence of an acid acceptor. Suitable acylating agents include acid halides such as bromide or chloride, an acid in the presence of a condensation promoting agent such as dicyclohexylcarbodiimide or its chemical equivalent, and acid anhydrides. Such reactions are generally carried out in a non-hydroxylic solvent at a non-extreme temperature.
The following examples will serve to further illustrate the invention:
EXAMPLE 1
Trans-2,2-dimethyl-4-piperidino-6-cyano-3,4-dihydro-2H-benzo[b]pyran-3-ol
4-Cyanophenol (19.6 g), sodium hydroxide pellets (9.9 g), 3-chloro-3-methylbut-1-yne (40.85 g) and benzyltrimethylammonium hydroxide (34.5 g, 40% in methanol) were stirred in methylene chloride (150 ml) and water (150 ml) at room temperature for 4 days. After separation of the layers, the aqueous layer was extracted twice with chloroform. The combined organic extracts were evaporated and the residue taken up in ether and washed with water and 2N sodium hydroxide solution before drying over anhydrous sodium sulphate. Removal of solvent and drying agent gave an oil (15.72 g). Distillation at 0.5 mm Hg gave the analytic material as the fraction boiling at 96°-102° C. (10.13 g).
Cyclisation of the 3-(p-cyanophenoxy)-3-methybut-1-yne (9.77 g) was accomplished by heating in diethylaniline at 210°-220° C. under nitrogen. Purification by distillation, and extraction with dilute hydrochloric acid gave 2,2-dimethyl-6-cyano-2H-benzo[b]pyran as a colourless oil (6.84 g), which slowly crystallised on standing, having a nmr spectrum showing signals at δ 1.46, 6.25 (d, J=10), 5.67 (d, J=10,), 6.74 (d, J=8), 7.18 (d, J=2), 7.34 (q, J32 8, 2).
To a stirred cooled solution of 2,2-dimethyl-6-cyano-2H-benzo[b]pyran (6.56 g) in dimethyl sulphoxide (65 ml) and water (1.30 ml) was added freshly crystallized N-bromosuccinimide (12.63 g) in one portion. Dilution with water after stirring for an additional 1 hour, and isolation via ethyl acetate gave trans-2,2-dimethyl-3-bromo-6-cyano-3,4-dihydro-2H-benzo[b]pyran-4-ol as a white crystalline solid (10.54 g), a small portion of which recrystallised from 60-80 petroleum ether had m.p. 128°-128.5° C.
This bromohydrin (5.63 g) was stirred with sodium hydroxide (0.80 g) in dioxan (75 ml) and water (18 ml) at room temperature for 3 hours. Work up by dilution and extraction with ethyl acetate gave 2,2-dimethyl-3,4-epoxy-6-cyano-3,4-dihydro-2H-benzo[b]pyran (4.35 g) as a colourless oil having signals at δ 1.26 and 1.54 (--CH 3 ), 3.80 (d, J=4, H-4), 3.40 (d, J=4, H-3), 6.77 (d, J=8, H-8), 7.43 (q, J=8.2, H-7) and 7.58 (d, J=2, H-5) in its nmr spectrum.
Treatment of 2,2-dimethyl-3,4-epoxy-6-cyano-3,4-dihydro-2H-benzo[b]pyran (2.09 g) with piperidine (0.86 g) in refluxing ethanol (60 ml) for 24 hours followed by evaporation of solvent gave a yellow oil which was dissolved in the minimum quantity of ethanol and treated with ethereal hydrogen chloride to give crystals of trans-2,2-dimethyl-4-piperidino-6-cyano-3,4-dihydro-2H-benzo[b]pyran-3-ol hydrochloride on standing (2.06 g) of m.p. 253°-257° C.
EXAMPLE 2
Trans-2,2-dimethyl-4-isopropylamino-6-cyano-3,4-dihydro-2H-benzo[b]pyran-3-ol
By substituting an equivalent amount of isopropylamino for piperidine in the procedure of Example 1, there was obtained trans-2,2-dimethyl-4-isopropylamino-6-cyano-3,4-dihydro-2H-benzo[b]pyran-3-ol, m.p. 251° C.
EXAMPLE 3
Trans-2,2-dimethyl-4-pyrrolidino-6-cyano-3-4-dihydro-2H-benzo[b]pyran-3-ol
4-Cyanophenol (19.60 g), sodium hydroxide (9.90 g), 40% benzyltrimethylammonium hydroxide in methanol (34.50 g) and 3-methyl-3-chlorobutyne (25.50 g) were stirred in water (150 ml) and dichloromethane (150 ml) for 5.5 days at room temperature. After evaporation of the layers, the aqueous layer was extracted twice with chloroform, and the combined organic phase evaporated leaving a gum which was taken up in ether and washed three times with 10% sodium hydroxide solution and with water before drying over magnesium sulphate. Removal of drying agent and solvent gave a viscous liquid having absorptions in the IR (film) at 2100, 2220, 3290 cm -1 . This liquid (20.91 g) was heated in o-dichlorobenzene (40 ml) at reflux temperature for 1.5 hours under nitrogen. After distillation of the solvent the fraction boiling at 110°-114°/0.02 mmHg (16.57 g) was collected, which on standing formed a low melting solid, having an IR absorption at 2230 cm -1 . (see M. Harfenist and E. Thom, J. Org. Chem., 37 841 (1972) who quote m.p. 36°-37°).
Addition to this 6-cyanochromene (16.50 g) dissolved in dimethyl sulphoxide (15 ml) containing water (3.24 ml), of N-bromosuccinimide (31.90 g) with vigorous stirring and cooling, followed by dilution with water and extraction with ethyl acetate gave a mixture which was boiled in acetone (300 ml) and water (100 ml) for 5 hours to hydrolyse the small amount of 3,4-dibromide present. Evaporation of solvents gave 2,2-dimethyl-3-bromo-6-cyano-3-4-dihydro-2H-benzo[b]pyran-4-ol as white crystals (24.37 g). A small sample had m.p. 128°-128.5° from 60°-80° petroleum ether, nmr (CDCl 3 ) δ 1.43 (3H), 1.62 (3H), 7.48 (1H, exchangeable) 4.07 (1H, d, J=9) 4.87 (1H, d, =9), 6.80 (1H, d, J=8), 7.43 (1H, q, J=8, 2), 7.78 (1H, d, J=2). Anal. Calcd. for C 12 H 12 NO 2 Br: C, 51.07; H, 4.26; N, 4.96; Br, 28.37. Found: C, 50.95; H, 4.38; N, 5.03; Br, 28.39%.
The bromohydrin (24.30 g) was stirred with sodium hydroxide pellets (5.00 g) in water (250 ml) and dioxan (200 ml) for 3 hours at room temperature. The solvents were removed by distillation under high vacuum and the residue taken up in ether and washed with water and brine before drying over magnesium sulphate. Removal of drying agent and solvent and gave crude 2,2-dimethyl-3-4-epoxy-6-cyano-3-4-dihydro-2H-benzo[b]pyran: (16.02 g) as a gum, having an absorption at 2230 cm -1 in the IR and Nmr (CCl 4 ) δ 1.26 (3H), 1.54 (3H), 3.40 and 3.80 (each 1H, d, J=4), 6.77 (1H, d, J=8), 7.43 (1H, q, J=8, 2), 7.58 (1H, d, J=2).
This epoxide (16.00 g) and pyrrolidine (7.20 ml) were refluxed in ethanol (240 ml) for 3.5 hours. Removal of solvent, addition of ethyl acetate, and washing with water was followed by extraction with 5N hydrochloride acid. The acidic extract was basified with 10N sodium hydroxide solution and extraction with ethyl acetate gave a gum which was taken up in diethyl ether containing a little ethanol and treated with ethereal hydrogen chloride. The precipitate was collected and washed with diethyl ether leaving trans-2,2-dimethyl-4-pyrrolidino-6-cyano-3,4-dihydro-2H-benzo[b]pyran-3-ol-hydrochloride as a white solid (11.02 g), m.p. 202°-204°; IR absorption at 2220 cm -1 ; nmr (CDCl 3 ) δ 1.19 (3H), 1.73 (3H), 2.22 (4H, broad m), 3.13 (2H, broad m), 3.97 (2H, broad m), 4.20, (1H, d, J=8), 4.86 (1H, d, J=8), 5.58 (s, 1 exchangeable H, broad), 6.87 (1H, d, J=8), 7.47 (1H, q, J=8, 2), 8.72 (1H, d, J =2). Anal. Calcd. for C 16 H 21 N 2 O 2 Cl: C, 62.23; H, 6.86; N, 9.07; Cl, 11.48, Found: C, 62,34; H, 6.73; N, 8.82; Cl, 11.40%.
EXAMPLE 4
Trans-2,2-dimethyl-3-(2,2-dimethylpropanoyloxy)-4-pyrrolidino-6-cyano-3,4-dihydro-2H-benzo[b]pyran
To a solution of 4-dimethylaminopyridine (0.98 g) in dichloromethane (50 ml) was added 2,2-dimethylpropanoyl chloride (0.69 ml) dropwise and with gentle stirring, followed by crude trans-2,2-dimethyl-4-pyrrolidino-6-cyano-3,4-dihydro-2H-benzo[b]-pryan-3-ol (2.50 g) in dichloromethane (50 ml) during 4 minutes. The resulting red solution was heated under reflux for 40 hours before cooling and evaporation of solvent. The orange residue was taken up in ethyl acetate and washed with water, dried and evaporated leaving a mustard coloured solid (2.97 g) which was separated by chromatography on silica gel (110 g) with mixtures of ethyl acetate and 69°-80° petroleum ether using a gradient elution technique, into crude ester (1.12 g) and starting material (1.13 g). Recrystallization of the crude material from 60°-80° petroleum ether gave trans-2,2-dimethyl-3-(2,2-dimethylpropanoyloxy)-4-pyrrolidino-6-cyano-3,4-dihydro-2H-benzo[b]pyran (0.73 g) as white crystals of m.p. 109°-110° C.; IR absorptions at 1730, 2220 cm -1 ; nmr (CDCl 3 ) δ 1.24 (9H), 1.29 (3H), 1.41 (3H), 1.75 (4H, broad m), 2.73 (4H, broad m), 4.09 (1H, d, J=9), 5.33 (1H, d, J=9), 6.86 (1H, d, J=8), 7.43 (1H, q, J=8, 2), 7.74 (1H, d, J=2). Anal. Calcd. for C 21 H 28 N 2 O.sub. 3 : C, 70.76; H, 7.92; N, 7.86. Found: C, 70.74; H, 8.03, N, 7.76%.
EXAMPLE 5
Trans-2,2-dimethyl-3-methoxy-4-pyrrolidino-6-cyano-3,4-dihydro-2H-benzo[b]pyran
To potassium t-butoxide (1.03 g) in dry toluene (40 ml) was added dropwise with stirring trans-2,2-dimethyl-4-pyrrolidino-6-cyano-3,4-dihydro-2H-benzo[b]pyran-3-ol (2.50 g) in toluene (100 ml) under nitrogen. After 10 minutes, methyl iodide (0.62 ml) in toluene (20 ml) was added dropwise, and the resulting yellow reaction mixture was stirred at 75°-80° C. for 16 hours. Cooling, and cautious addition of water, separation of the organic layer, washing with water, drying and evaporation gave a red gum (2.66 g) which was separated, by column chromatography on silica gel (110 g) with mixtures of ethyl acetate and 60°-80° petroleum ether using a gradient elution technique, into crude ether (1.34 g) and starting material (0.91 g). One crystallization from 60°-80° petroleum ether gave trans-2,2-dimethyl-3-methoxy-4-pyrrolidino-6-cyano-3,4-dihydro-2H-benzo[b]pyran (1.06 g) as off-white crystals m.p. 108°-109° C.; nmr (CDCl 3 ) δ 1.22 (3H), 1.50 (3H), 1.80 (4H, broad m), 2.76 (4H, broad m), 3.39 (1H, d, J=9), 3.51 (3H), 3.98 (1H, D, J=9), 6.76 (1H, d, J=8), 7.34 (1H, q, J=8, 2), 7.72 (1H, d, J=2). Anal. Calcd. for C 17 H 22 N 2 O 2 : C, 71.30; H, 7.74; N, 9.78. Found: C, 71.12; H, 7.96; N, 9.72%.
EXAMPLE 6
Resolution of trans-2,2-dimethyl-4-pyrrolidino-6-cyano-3,4-dihydro-2H-benzo[b]pyran-3-ol
Racemic trans-2,2-dimethyl-4-pyrrolidino-6-cyano-3,4-dihydro-2H-benzo[b]pyran-3-ol (4.12 g) and (+)-tartaric acid (2.55 g), both dissolved in ethanol, were combined and the resulting solution evaporated leaving a cream foam. Three recrystallizations from ethanol gave a tartrate (1.01 g) of mp 173°-173.5° and an [α] water D =-64°. Basification with NaHCO 3 and extraction with diethyl ether gave the minus isomer of the free base (0.64 g) of [α] EtOH D =-101°. Treatment of an ethereal solution of this base base with ethereal-anhydrous HCl and one recrystallisation from ethanol- diethyl ether gave (-)-trans-2,2-dimethyl-4-pyrrolidino-6-cyano-3,4-dihydro-2-H-benzo-[b]-pyran-3-ol hydrochloride (0.49 g) of m.p. 184°-185° C., [α] water D =-98°. Anal. Calcd. for C 16 H 21 N 2 O 2 Cl: C, 62.23; H, 6.85; N, 9.07; Cl, 11.48. Found: C, 62.29; H, 7.11; N, 9.17; Cl, 11.39%.
The mother liquors remaining after the three recrystallizations of the tartrate prepared from the racemic free base and (+)-tartaric acid were evaporated to dryness, dissolved in water, and rendered basic with sodium bicarbonate. Extraction with diethyl ether gave crude free base (3.10 g) which was treated with (-)-tertaric acid (1.67 g) in ethanol. Evaporation gave a cream foam (4.78 g).
Four recrystallizations from ethanol gave a tartrate (1.42 g) of mp 172.5°-173.5° and [α] water D +58°. Treatment with sodium bicarbonate and extraction with diethyl ether gave the plus isomer of the free base (0.88 g) of [α] EtOH D =+115°. Treatment of an ethereal solution of this free base with ethereal anhydrous hydrogen chloride and one recrystallization from ethanol-diethyl ether gave (+)-trans-2,2-dimethyl-4-pyrrolidino-6-cyano-3,4-dihydro-2H-benzo[b]pyran-3-ol hydrochloride (0.87 g) of mp 175°-177° C., [α] water D =+100°. Anal. Calcd. for C 16 H 21 N 2 O 2 Cl: C, 62.23; H, 6.85; N, 9.07; Cl, 11.48. Found: C, 61.94; H, 7.06; N, 9.28; Cl, 11.63%.
EXAMPLE 7
Trans-2,2-dimethyl-4-pyrrolidino-6-cyano-3,4-dihydro-2H-benzo[b]pyran-3-ol-hydrochloride
Trans-2,2-dimethyl-3-bromo-3,4-dihydro-2H-benzo[b]pyran-4-ol (1.57 g) was dissolved in pyrrolidine (2.0 ml) and the solution heated under reflux for 25 min. After cooling, the solution was subjected to reduced pressure to remove traces of pyrrolidine. The residual gum was dissolved in ethyl acetate and washed with aqueous sodium carbonate solution and water before extraction with 1N hydrochloric acid. The organic layer was discarded, and the aqueous layer was basified with 2.5N sodium hydroxide and extracted with ethyl acetate. Water washing, drying, and evaporation of the organic layer gave the crude trans-2,2-dimethyl-4-pyrrolidino-6-cyano-3,4-dihydro-2H-benzo[b]pyran-3-ol (0.85 g) having identical chromatographic characteristics to that described in Example 3.
EXAMPLE 8
Trans-2,2-dimethyl-4-pyrrolidino-6-cyano-3,4-dihydro-2H-benzo[b]pyran-3-ol hydrochloride, magnesium stearate and microcrystalline cellulose are blended together and passed through a 40 mesh sieve (UK). The mixture is tabletted on a conventional rotary machine to produce a batch of 5000 tablets of the following:
Magnesium stearate: 0.2 mg
Active compound: 10 mg
Microcrystalline cellulose: 9.8 mg
EXAMPLE 9
Trans-2,2-dimethyl-4-pyrrolidino-6-cyano-3,4-dihydro-2H-benzo[b]pyran-3-ol hydrochloride, sodium lauryl sulphate, lactose and sodium starch glycollate are blended together and passed through a 40 mesh sieve (UK). The mixture is tabletted on a conventional rotary machine to produce a batch of 5000 tablets of the following composition:
Active compound: 5 mg
Magnesium lauryl sulphate: 0.1 mg
Lactose: 103 mg
Sodium starch glycollate: 1.9 mg
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2,2-Dimethyl-3,4-dihydro-2H-benzo[b]pyran-3-ols bearing an amino group in the 4-position and a cyano group in the benzo ring, their salts, esters and ethers, demonstrate excellent vasodilatory activity. The compounds, of which trans-2,2-dimethyl-4-isopropylamino-6-cyano-3,4-dihydro-2H-benzo[b]pyran-3-ol is a representative embodiment, can be prepared from the corresponding 3,4-epoxy derivative upon treatment with an amine.
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This application claims priority on provisional Application No. 60/304,794 filed on Jul. 13, 2001, the entire contents of which are hereby incorporated by reference.
FIELD OF THE INVENTION
The invention relates to a synthetic grass turf to provide a game playing surface, and more particularly relates to a drainage system for a synthetic grass turf assembly for installation on a supporting substrate to provide a game playing surface.
BACKGROUND OF THE INVENTION
Synthetic grass sport surfaces are well known. They are used to replace natural grass surfaces which do not stand up well to wear and which require a great deal of maintenance. Also, natural grass surfaces do not grow well in partly or fully enclosed sport stadiums. The synthetic grass surfaces stand up to wear much better than the natural grass surfaces, do not require as much maintenance, and can be used in closed stadiums. Some synthetic grass surfaces comprise rows of strips or ribbons of a synthetic material, extending vertically from a backing mat with particulate material in-filled in between the ribbons on the mat. The ribbons of synthetic material usually extend a short distance above the layer of particulate material and represent blades of grass.
In order to reduce the abrasive nature of the synthetic grass infills and stabilize the top surface of the infills to retain a resilient grass-like surface that does not deteriorate in quality, or compact over time through use, a unique infilled layer of multiple distinct courses of a particulate material, for example, is disclosed in U.S. Pat. No. 5,958,527 which issued to Prevost on Sep. 28, 1999 and was assigned to the Assignee of this application. In Assignee's Canadian patent application No. 2,218,314, filed Oct. 16, 1997 and published on Sep. 10, 1998, the Assignee discloses a synthetic grass turf assembly.
When the synthetic grass turf assembly is installed on a sport field, however, an efficient drainage system under the grass turf assembly is needed because the water permeable backing cannot function well without a drainage system underneath to prevent water from accumulating on the turf surface. With certain infill materials, slow water evacuation could cause the infill material to float off of the surface, thereby creating an additional maintenance cost issue.
For example, U.S. Pat. No. 5,976,645, issued to Daluise et al on Nov. 2, 1999, discloses a vertical drainage system for a rubber-filled synthetic turf. The drainage system disclosed in this patent is deployed below a fabric backing layer of a synthetic turf and incorporates a porous geotextile membrane between an open graded aggregate layer and a sand layer above the aggregate layer to prevent the movement of one aggregate layer into the other. The drainage passages are generally formed with the 2-inch thick porous layer of sand and the 6-inch thick layer of sand and stone mixture. The draining rate depends on the particulate sizes and compact conditions of those layers. The porous geotextile membrane is used only for separating those two different layers.
A multiple-layer net structure for fluid drainage, particularly for geotechnical use, is well known in the art. A triplanar net, described in U.S. Pat. No. 5,255,998, which issued to Beretta on Oct. 26, 1993, for example, includes a first layer of mutually parallel wires which is rigidly associated with a second or intermediate layer of substantially mutually parallel wires, which are inclined with respect to the wires of the first layer. A third layer of wires is rigidly associated with the intermediate layer, on the opposite side thereof with respect to the first layer, and has substantially mutually parallel wires which are inclined with respect to the wires of the second or intermediate layer. In general and geotechnical use, such multiple-layer nets are buried and inclined with respect to the horizontal plane, so as to allow the drainage of any liquids to be eliminated from the region in which the drainage nets are located.
However, those multiple layer nets have not been suggested to be used in a drainage system for a synthetic grass turf assembly. Unlike other environments in which the multiple layer nets are used for drainage, a synthetic grass turf assembly for providing a game playing surface is a dynamic system continuously in movement under the influence of bouncing balls, vibration, and impacts from the feet and bodies of players in contact with the top surface of the turf. The more rigid grids do not alleviate the resilience of the synthetic turf. Many efforts have so far been made for improving such dynamic properties of synthetic grass turf assemblies.
Another problem with regard to the use of multiple layer nets in synthetic grass turf assembly is deformation resulting from radiant heat from the sun. A deformed multiple layer net not only statically affects the formation of a planar game playing surface but also jeopardizes the dynamic property thereof. For instance, the synthetic grass surface weight with an infill will not always correct the deformations caused by the curling of the edges of the net caused by absorbing heat from the sun. The net itself can form undulations by heat absorption both prior to and after the installation of the artificial grass system.
Therefore, there exists a need for a more efficient drainage system for a synthetic grass turf assembly, which meets the dynamic requirements for a game playing surface.
SUMMARY OF THE INVENTION
It is one object of the invention to provide a drainage system for a synthetic grass turf assembly for installation on a supporting substrate to provide a game playing surface.
It is another object of the invention to provide an improved drainage system for a synthetic grass turf assembly using a spacing device to provide additional draining capacity to the system to facilitate drainage.
It is a further object of the invention to provide a synthetic grass turf assembly for installation on a supporting substrate to provide a game playing surface, which includes an efficient drainage system to prevent water from accumulating on the turf surface.
It is also contemplated to use the drainage system embodying drainage tiles. Such drainage tiles are in the form of one-foot square, or more, interlocking tiles of molded plastic with vertical through openings.
A drainage system for a synthetic grass turf assembly having a flexible and water permeable sheet backing for installation on a supporting substrate to provide a game playing surface generally comprises a flexible, three-dimensional spacing device positioned between the backing and the supporting substrate, supporting the undersurface of the backing and having the backing spaced apart from the supporting substrate to form draining passages in both vertical and substantially horizontal directions.
The spacing device may be an assembly of interconnecting tiles preferably selected from plastics materials, having a plurality of elongated channels preferably parallel to each other, on at least one surface of the tile as well as through openings extending from one surface of the tile to the other, in a manner such that water is enabled to flow through the tile in a direction perpendicular to a major plane defined by the tile, and also in another direction from one edge of the tile to another edge such that the water to be drained can flow throughout the interconnected tile assembly. It is desirable to have the supporting substrate sloped to facilitate drainage.
The spacing device may alternatively be a grid preferably selected from geotextile materials, having a plurality of elongated grid members preferably parallel to each other, bonded with link elements in a manner such that water is enabled to flow through the grid in a direction perpendicular to a major plane defined by the grid, and also in another direction from one edge of the grid to an opposite edge. It is desirable to have the supporting substrate sloped downwardly from a field centerline to two opposed edges to facilitate drainage.
In one embodiment, it is desirable that the support substrate has a non-porous and stable crushed stone base directly under the spacing grid or tiles. This stone is readily available and is lower in cost than specially graded stone. This method would reduce the cost of the substrate construction by allowing the water to drain horizontally to the edges, thus reducing the need for a more complicated and costlier drainage system under the support substrate. This in effect simulates the characteristics of having a nonporous asphalt or concrete base. A geotextile fabric or impermeable liner could be placed directly on the stone base to prevent the water from percolating through the stone base.
The latter drainage device is a grid type of plastics material which preferably comprises a plurality of longitudinal grid members in a base layer to form the substantially horizontal drainage passages therebetween when the grid is positioned between the backing and the supporting substrate. A plurality of link elements in two outer layers associated with two opposite sides of the base layer bond the grid members in position to form the grid without blocking either the vertical draining passages or the substantially horizontal draining passages. The spacing grid is preferably made of an extruded triplanar plastic structure having adequate properties in regard to flexibility, firmness, and resilience. White colour is preferred to reduce heat absorption and, therefore, to prevent or minimize deformation of the spacing grid from the heat of the sun.
It may also be desirable to place a porous aggregate layer, preferably formed with selectively sized crushed rocks, between the supporting substrate and the spacing device so that water is enabled to be drained through the spacing device into the porous aggregate layer.
An additional advantage of using the spacing device relates to the property of the adequate combination of resilience and firmness of the material. The resilience yet firmness of the spacing grid will further improve the impact absorption capability of the synthetic grass turf assembly which is an important property of a game playing surface especially in shorter pile infilled synthetic grasses.
Other features and advantages will be better understood with reference to a preferred embodiment described below.
BRIEF DESCRIPTION OF THE DRAWINGS
Having thus generally described the nature of the invention, reference is now given to drawings by way of examples only illustrating a preferred embodiment in which:
FIG. 1 a is a cross-sectional view of an installed synthetic grass turf assembly with a drainage system according to a preferred embodiment of the invention;
FIG. 1 b is a cross-sectional view of an installed synthetic grass turf assembly with a drainage system according to an alternate embodiment of the invention;
FIG. 2 is a plan view of a spacing grid used in the embodiment shown in FIG. 1 ;
FIG. 3 is a plan view of a layer of drainage tiles;
FIG. 4 is a perspective view taken from the bottom of another embodiment of a drainage tile;
FIG. 5 is a perspective view taken from the top of still another embodiment of a drainage tile; and
FIG. 6 is a perspective view, taken from the side, of the embodiment shown in FIG. 5 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
With reference to FIG. 1 , a synthetic grass turf assembly, generally indicated at numeral 10 , is installed on a supporting soil substrate to provide a game playing surface. The synthetic grass turf assembly 10 has a pile fabric including a flexible sheet backing 14 that in the embodiment shown is a two-ply open weave fabric. Extending upwardly from an upper surface of the backing 14 is a large number of upstanding synthetic ribbons 16 . As indicated in FIG. 1 , the ribbons 16 are tufted through the backing 14 spaced apart in rows by a distance W and of a length L. The length is selected depending upon the depth of an infill 18 and the desired resilience of the completed synthetic grass turf assembly.
The ribbons 16 may include a mixture of multiple fibers and the single ribbons fibrillated when manufactured, or fibrillated on site or left in their original state. The on-site fibrillation can be done by passing over the turf surface with a wire brush, for example, or other brushing means after installation of the infill 18 . Generally, thin fibers cannot be easily top-dressed on site since they are more fragile and fall more easily than thicker fibers, especially in high heat environments. The mix of thick and thin fibers on the ribbons can cause a ball to roll in a more predictable manner depending on the resistance of the fibers to the moving ball. Modification of the ribbon width and density in the turf will also modify the ball-rolling characteristics.
The ribbons 16 are made from suitable synthetic plastic material which is extruded in a strip that is relatively wide and thin. The details of the synthetic ribbons 16 and the porous sheet backing 14 as well as the method for attaching the ribbons 16 to the sheet backing 14 are described in Canadian Patent Application 2,218,314 which is incorporated herein by reference.
Deposited interstitially between the upstanding ribbons 16 upon the upper surface of the backing 14 is the infill layer 18 of particulate matter. The particulate matter may be selected from any number of commonly available hard granules, such as sand, small rocks or other graded particulate matter, and resilient granular, such as crumb rubber.
The infill layer 18 is made up of a base course 20 , a middle course 22 , and a top course 24 . The base course 20 is substantially exclusively of hard sand granules disposed immediately upon the top surface of the backing 14 . The middle course 22 is of intermixed hard sand granules and resilient rubber granules. The mix is selected on the basis of a weight ratio greater than 2 to 1 of hard and resilient granules respectively. The top course 24 is substantially exclusively of resilient rubber granules. It is noted that the infill can be all rubber.
An upper portion 26 of the synthetic ribbons 16 extends upwardly from a top surface 28 of the top course 24 . The resulting artificial turf surface can be adapted for several indoor and outdoor uses, such as athletic playing fields, horse racing, and recreational areas. The detailed characteristics of the infill layer 18 and the selection, in particular, of the particulate sizes and unit weights of the respective courses are described in U.S. Pat. No. 5,958,527 which is incorporated herein by reference.
The supporting soil substrate 12 is formed, for example, by removing turf, loam, etc., and grading and compacting the earth. Excavation of materials is necessary to establish a proper grade of the supporting soil substrate 12 to a tolerance of about 1-inch per 10 feet. The supporting soil substrate 12 is compacted to about 95% Proctor density, if possible, to form a firm and stable surface. Then a layer of concrete or asphalt is placed on the compacted earth, in order to ensure the grade and to provide an impervious barrier to the water being drained. Instead of the concrete or asphalt, a layer of non-porous stone may be provided which is compacted to form a stone base 31 . This stone base may be relatively inexpensive, as it need not be graded. An impermeable membrane 33 can then be placed on the stone base 31 to complete the water barrier, as seen in FIG. 1 b . Preferably, the slope of the supporting substrate 12 is 0.5% to about 1%, depending on the IDF rainfall curves for specific areas, from the field center line downwards to opposed edges of the field in order to facilitate drainage.
Situated over the support substrate 12 , in one embodiment, is a spacing grid 32 , preferably made of extruded triplanar polypropylene or polyethylene material. The spacing grid 32 directly supports the undersurface of the backing 14 , and as a result, the backing 14 is spaced apart from the supporting substrate 12 .
The spacing grid 32 , more clearly shown in FIGS. 1 and 2 , includes a plurality of longitudinal grid members 34 which are parallel to each other and form a base layer of the grid, and a plurality of link elements 36 at one side and link members 38 at the other side of the spacing grid 32 which form two respective outer layers of the grid to bond the longitudinal grid members 34 in position. The link elements 36 and 38 are elongated and extend diagonally with respect to the longitudinal grid members 34 according to this embodiment of the invention. The diagonal directions of the respective link elements 36 and 38 at the opposite sides of the spacing grid are angularly crossed, preferably perpendicular to each other, as shown in FIG. 2 . The spacing grid has a thickness that can be from ⅕ inch (5.08 mm) to 1½ inch (38.1 mm) in accordance with this embodiment to provide an adequate draining space between the backing 14 and the porous aggregate layer 30 . The thickness of the spacing device is inversely proportional to the degree of slope of the field.
The spacing grid 32 with such a structure provides a plurality of draining apertures 40 defined by the longitudinal grid members 34 and the diagonal link elements 36 and 38 to permit water drained vertically from the grass turf through the spacing grid 32 in which water is drained toward the field edges.
The spacing grid 32 provides substantially horizontal draining passages defined between adjacent longitudinal grid members 34 , as indicated by numeral 42 in FIG. 1 , which permits water to flow freely along the passage 42 , horizontally through the spacing grid 32 when water is accumulated in the porous aggregate layer 30 and is enabled to be drained promptly through the layer 30 . For this purpose, the thickness of the base layer formed by the grid members 34 should be much greater than the thickness of the outer layers formed by the link elements 36 and 38 . The spacing grid 32 is preferably positioned in a direction such that the longitudinal grid members extend from the field center line to the opposed edges, aligning with the slope direction of the supporting soil substrate to achieve the best drainage result.
The spacing grid 32 is preferably manufactured in a light colour such as white because a dark coloured plastic spacing grid, installed outdoors, absorbs more heat energy which results in deformation thereof.
In high rainfall areas, a geotextile, that is, a non-woven porous membrane made of needle-punch poly-propylene, may be placed immediately over the spacing grid 32 . In fact, the geotextile membrane could be attached directly to the spacing grid 32 at the manufacturing plant. The membrane could also be woven.
The geotextile membrane prevents sand or other infill material from entering the interstices formed in the grid 32 which would tend to block the passages so formed in the grid 32 . This, however, would reduce the function between the grass surface and the geogrid and could cause movement of the grass surface which may result in line deformation unless the backing material has a non-slip characteristic that does not allow the grass to slide on it.
In a preferred embodiment, the backing 14 is made in accordance with Canadian patent application 2,218,314 and U.S. Pat. No. 5,958,927, herewith incorporated by reference. This backing prevents the infill from passing through the backing into the spacing grid 32 , thereby preventing blocking of the drainage passages.
Another preferred embodiment is illustrated in FIG. 3 . In this embodiment, the drainage device is in the form of interconnecting tiles 50 made up of individual tiles 52 . The tiles 52 are generally square but could be made up of various shapes. The tiles 52 include intersecting grooves or channels 53 defining square lugs 54 . The opposite surface of the tile 52 would have similar channels 53 and lugs 54 . Through openings 55 extend from one surface to the other and provide drainage passages for the vertical flow of the water, and communicate with the channels 53 in order to evacuate the water horizontally. The interconnected tiles would normally sit on the support substrate 12 and would be in direct contact with the backing 14 in order to allow the water to pass through the backing 14 and then along the channels 53 , on the top of the tiles 52 , or through the openings 55 to access the channels 53 on the bottom of tiles 50 .
FIG. 4 shows another embodiment of the tile 152 , in accordance with the present invention, having a bottom surface 152 a and a plurality of lugs 154 extending from the bottom surface 152 a . The lugs 154 define channels 153 to provide the necessary drainage from edge to edge. Through openings 155 are provided to allow drainage perpendicular to the tile 152 . Nails 156 are provided for anchoring the tiles to the support substrate 12 .
In yet another embodiment, the tiles 252 shown in FIGS. 5 and 6 show the through openings 255 as a pattern of openings defined by links 257 . Lugs 254 are provided on the bottom surface 252 a to define the channels 253 .
Although the above description and accompanying drawings relate to a specific preferred embodiment as presently contemplated by the inventor, it will be understood that the invention in its broad aspect includes mechanical and functional equivalents of the elements described and illustrated. Modifications and improvements to the above-described embodiment of the invention may become apparent to those skilled in the art. The foregoing description is intended to be exemplary rather than limiting. The scope of the invention is intended to be limited solely by the scope of the appended claims.
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A drainage system is provided for a synthetic grass turf assembly having a flexible and water permeable sheet backing for installation on a supporting soil substrate to provide a game playing surface. The draining system of the present invention prevents water from accumulating on the turf surface, which could cause the top-dressing layer to “float” and be moved by inundation. The draining system of the present invention includes a spacing grid disposed between the backing of the turf. The spacing grid is structured to permit water not only to be drained vertically through the spacing grid, but also to be drained horizontally through the spacing grid to the edges of the field. The spacing grid is made from one or more types of geotextile or plastics material with an adequate flexibility to improve the impact absorption capabilities and resilience of the synthetic grass turf assembly.
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FIELD OF THE INVENTION
The present invention generally relates to a steam distributor for applying steam to a continuously moving paper sheet wherein the steam distributor includes one or more drop-out steam profiling cartridges. Each cartridge, which is attached to the steam distributor with bolts, features a number of profiling zones that are covered by a contoured, smooth profiling screen from which steam is applied. Employment of drop-out cartridges affords quick and easy removal of the profiling screens for change-out or cleaning.
BACKGROUND OF THE INVENTION
The steam heating of a paper sheet is widely practiced in papermaking. The increase in sheet temperature that results provides increased drainage rates for the water thus reducing the amount of water to be evaporated in the drier section. Water drainage is improved by the application of steam principally because the heating of the sheet reduces the viscosity of the water, thus increasing the ability of the water to flow. Most of the heat transfer takes place when the steam condenses in the sheet. The condensation of the steam transforms the latent heat of the steam to sensible heat in the water contained by the sheet.
A particular advantage of the steam heating of the paper sheet is that the amount of steam applied may be varied across the width of the sheet along the cross machine direction so that the cross machine moisture profile of the sheet may be modified. This is usually carried out to ensure that the moisture profile at the reel is uniform. Techniques in the papermaking art for sensing the moisture profile of a sheet of paper are well known. If a sensing apparatus is positioned over the paper sheet, downstream of a steam distributor able to control the moisture profile, then after measuring the water profile in the sheet, steam can be applied in varying amounts on a selective basis across the sheet, thus achieving the required uniform moisture profile at the reel.
It is known to divide a steam distributor into compartments and to control the supply of steam to each compartment, thus controlling the moisture profile of the sheet. Fiber and dirt accumulate within the compartments and over time, the debris penetrates into the internal structures and interferes with steam flow. The steam distributor must be disassembled in order to clean the internal components.
U.S. Pat. No. 5,711,087 to Pazdera describes an apparatus for distributing steam to a paper web or calendar roll which includes a removable curved-shaped profile screen. The screen is mounted on the apparatus with clip members that interrupt the otherwise smooth exterior surface of the screen. In addition, the use of external clip members makes the removable screen susceptible to flexing outward with increasing steam pressure. Moreover, the clamped edge of the screens must often be separated from the clips on the frame using jarring force, then pried back into place. When they are reattached, the screens lose the intended tight fit against the baffles thereby allowing significant leakage between profiling zones. Finally, in these prior art designs where the screens are not permanently attached, the steam holes in the screen must be situated near either the leading or trailing edge of the steambox in order to minimize the machine direction (MD) length of the screen. Consequently, if a screen becomes too long in the MD, the screen tends to bow out which causes excessive and inconsistent leakage between profiling zones. These removable screen plates become warped and battered after only a few cleaning routines.
U.S. Patent Application 2006/0107704 to Passiniemi describes a steam distribution apparatus that is partitioned into a number of discharge chambers and includes screen plates which are welded to the partitions to prevent the screen plates from twisting or flexing. While the apparatus includes sealable slots for access to the internal compartments for cleaning, the slots afford only limited access.
SUMMARY OF THE INVENTION
The present invention is based in part on the development of a removable drop-out steam profiling cartridge that can be incorporated as part of a steam distribution apparatus. The cartridge is preferably fastened to the apparatus by bolts that are readily accessible from the back side of the apparatus. On its front side, the cartridge defines a plurality of isolated steam profiling zones that are separated by spaced-apart partitions or baffle panels that essentially eliminate the spilling over of steam from one profiling zone to the next. The profiling zones are covered by steam profiling screens having perforations through which steam exits. The profiling screens are welded to the baffles which enhances the structural integrity of the drop-out steam profiling cartridge. No external clamps or other devices are employed that would otherwise disrupt the smooth, curved exterior surface of the profiling screens. The drop-out cartridge design provides a rigid structure for cleaning.
Accordingly, one aspect of the invention is directed to an apparatus to distribute steam onto a moving sheet, the apparatus having a leading edge and a trailing edge relative to the moving sheet, the apparatus including:
an elongated steam chamber which has a front wall that defines a recess region;
a plurality of conduits each having an inlet located in the elongated steam chamber and an outlet;
a removable cartridge that is positioned in the recess region wherein the cartridge defines a plurality of compartments each of which is in communication with an outlet and wherein the cartridge has a front screen having a plurality of apertures through which steam can exit;
means for regulating the flow of steam through the inlet and outlet of each conduit; and
means for securing the removable cartridge to the recess region.
In another aspect, the invention is directed to an apparatus to distribute steam onto a continuously moving sheet that has an exterior contour wherein the apparatus has a leading edge and a trailing edge relative to the moving sheet, the apparatus including:
an elongated steambox header which has a front surface facing the moving sheet that defines a recess region;
a plurality of conduits each having an inlet located in the elongated steambox header and an outlet;
one or more removable cartridges that are juxtaposed along the length of the recess region wherein each cartridge comprises a frame that is partitioned along its length to form a plurality of profiling zones each of which is in communication with an outlet and wherein the frame has a front screen having apertures through which steam can exit and the screen defines an outer profiling surface with a contour conforming to the exterior contour of the moving sheet and which is flush with an exterior surface of the front surface of the elongated steambox header;
means for independently regulating the flow of steam through the inlet and outlet of each conduit; and
means for fastening each removable cartridge to the elongated steambox header characterized in that each cartridge can be unfastened from a back side of the steambox header.
In a further aspect, the invention is directed to a method of distributing steam onto a continuously moving sheet which includes the steps of:
(a) positioning an apparatus having a leading edge and a trailing edge relative to the moving sheet, wherein the apparatus comprises:
(i) an elongated steam chamber that is in communication with a source of steam and which has a front wall that defines a recess region; (ii) a plurality of conduits each having an inlet located in the elongated steam chamber and an outlet; (iii) a removable cartridge that is positioned in the recess region wherein the cartridge defines a plurality of compartments each of which is in communication with an outlet and wherein the cartridge has a front screen having a plurality of apertures through which steam can exit; (iv) actuators for regulating the flow of steam through the inlet and outlet of each conduit; and (v) means for securing the removable cartridge to the recess region; and
(b) activating the actuators to allow steam through the conduits thereby delivering steam onto the moving sheet.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A is a cross sectional side view of a partially exposed portion of the steam distributor apparatus as steam is applied onto the surface of a moving sheet of paper that is supported on a roller;
FIG. 1B is a cross sectional side view of a partially exposed portion of the steam distributor apparatus showing the drop-out steam profiling cartridge removed;
FIG. 2 is a cross sectional side view of a partially exposed portion of the steam distributor apparatus showing an actuator; and
FIG. 3 is front view of the steam distribution apparatus illustrating the profiling compartments or zones and the positions of the cartridge bolts and steam discharge conduits.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
FIG. 1A illustrates a steam distributor apparatus 10 that is particularly suited for applying steam to a paper web or calendar roll in a sheet making process. Papermaking devices are well known in the art and are described, for example, in U.S. Pat. No. 5,539,634 to He and U.S. Pat. No. 5,022,966 to Hu, U.S. Pat. No. 4,982,334 to Balakrishnan, U.S. Pat. No. 4,786,817 to Boissevain et al., and U.S. Pat. No. 4,767,935 to Anderson et al. which are incorporated herein by reference.
Apparatus 10 includes housing or steambox 2 that encloses a main steam distribution header 32 which runs the length of the apparatus and which is connected to at least one source of steam (not shown). Steam distribution header 32 includes an interior wall 6 and an exterior wall 4 which defines an exterior recess region into which is a drop-out steam profiling cartridge 42 is inserted and attached. A pair of pipes 12 , 22 is welded onto interior wall 6 and exterior wall 4 ; each pipe is configured to provide a conduit or passageway through which a cartridge bolt can be inserted to fasten drop-out cartridge 42 . Specifically, cartridge bolts 14 , 24 are inserted through pipes 12 , 22 , respectively, and cartridge 42 includes two corresponding threaded mating nuts 18 , 28 , that are welded thereto, and that receive the distal ends of cartridge bolts 14 , 24 , respectively. Cartridge 42 is fastened by tightening cartridges bolts 14 , 24 whose proximal ends 16 , 26 are readily accessible through an inner enclosure 56 located at the back of steam distribution apparatus 10 . By removing wing-nuts 64 , 68 , cover 62 can be removed from flange 60 to expose enclosure 56 .
Steam exiting an opening 52 of valve sleeve 58 expands into the compartment or profiling zone 40 within cartridge 42 before being discharged through perforations in a profiling screen 38 and onto paper sheet 50 which is transported on a continuously rotating roll, for example. In this fashion, there is uniform steam distribution from a leading edge 51 to a trailing edge 53 of contoured profiling screen 38 as the sheet of material moves across profiling zone 40 in the machine direction. Condensate that forms on the bottom of profiling zone 40 seeps through a drain hole 54 and out through a condensate drain. The steam distributor apparatus is also equipped with a pressure gauge 34 and a main header condensate drain 36 .
The exterior or front surface of profiling screen 38 is preferably contoured to match the shape of paper sheet 50 . In this case, the concave-shaped curvature of profiling screen 38 is particularly suited for applying steam to a roll of material. The gap or distance between profiling screen 38 and paper sheet 50 typically ranges from 10 mm to 20 mm. The exterior surface of profiling screen 38 is flush with the outer, front surface of housing 2 . At the perimeter where the edges of cartridge 42 meet the edge of the recess region, silicone fillers are not needed to create a smooth continuous surface.
FIG. 1B shows the steam distribution apparatus with cartridge 42 removed from recess region 8 that is configured within exterior wall 4 . This can be readily accomplished by loosening cartridge bolts 14 , 24 to disengage the bolts from threaded nuts 18 , 28 , respectively. Cartridge 42 is preferably configured as a U-Shaped frame 30 that is covered by profiling screen 38 that has perforations or apertures that are sized and distributed to allow steam to discharge through in a predetermined pattern. Steam distributor apparatus 10 also includes a plurality of actuators each of which regulates the amount of steam which is discharged through an opening 52 of valve sleeve 58 . The use of cartridge bolts 14 , 24 to secure drop-out cartridge 42 and to maneuver profiling screen 38 into U-Shaped frame 30 permits design and manufacturing tolerances to be flexible without sacrificing performance of the steam distributor apparatus. The manufacturing process can be more readily streamlined.
As shown in FIG. 2 , high pressure steam that is supplied to main steam distribution header 32 is drawn into valve sleeve 58 through an annular opening 55 that is located between the valve sleeve 58 and pipe 74 . The amount of steam drawn is controlled by actuator 70 which is connected via connector 72 to a pneumatic supply which tunes or regulates the actuator by pressurizing a diaphragm that is on top of a piston that is located inside actuator 70 . The piston is connected to a measuring plug that moves inside pipe 74 to control the amount of steam that goes into a profiling zone 40 within cartridge 42 . Pneumatic actuators for regulating steam flow in a steam distribution apparatus are described, for instance, in U.S. Pat. No. 4,398,355 to Dove and U.S. Pat. No. 4,351,700 to Dove, which are incorporated herein by reference.
By monitoring and controlling the steam flow into each of a plurality of profiling zones 40 , a predetermined steam profile can be injected onto a sheet along its cross direction. The steam profile, as measured along the length of the steam distribution apparatus, can be uniform or non-uniform so that the sheet or web of material can be exposed to a steam curtain having different amounts of steam in the cross direction.
FIG. 3 illustrates a front view of steam distributor apparatus 10 exposing the compartment of the drop-out steam profiling cartridges without the profiling screens. Housing 2 , which is flanked by endplates 90 , 92 , forms an elongated structure having a front wall configured to serve as a recess region into which one or more drop-out steam profiling cartridges are secured. An external source of steam is connected through steam line 94 to steam distribution apparatus 10 and excess steam in the form of condensate exits through drain 96 .
As illustrated, a plurality of steam profiling zones or compartments spans the length of steam distributor apparatus 10 . Steam is supplied to each compartment via an opening 86 of a valve sleeve. The compartments are isolated from one another by zone dividers or baffles 102 , 104 which are spaced apart laterally and to which a stream profiling screen 38 ( FIG. 1B ) is welded. Baffles 102 , 104 also serve as internal gussets onto which U-Shaped frame 30 ( FIG. 1B ) of the drop-out steam profiling cartridge 42 ( FIG. 1B ) is welded. In this fashion, the steam profiling screen is held in place so as not to flex or expand outwardly and possibility come into contact with the paper sheet should the pressure in the compartment increase suddenly. In addition, the baffles prevent the spill-over of steam between steam profiling zones which minimizes the overall response width in the process of monitoring and controlling the steam profile. Since the steam profiling screen is welded to the cartridge, the screen can withstand a higher pressure from the steam jet at the actuator outlet than with conventional designs. For example, steam jet 52 may be allowed to impact steam profiling 38 screen directly without the need for a protective plate as illustrated in FIGS. 1A and 1B . As a result, a higher range of pressure distribution within the profiling zones or compartments can be achieved.
The structural integrity of the drop-out cartridge allows for optimal machine-direction placement of the perforations in profiling screen 38 ( FIG. 1B ). In particularly, unlike prior designs where the perforations are restricted primarily to the leading or trailing edges of the steambox, with the drop-out steam profiling cartridge, the screen holes can be moved to the center of the contoured surface. This feature may be beneficial in reducing the cross-directional response width (fanning out) of the process.
As described above, cartridge bolts are positioned along the length of the apparatus to secure the drop-out steam profiling cartridge. As shown in FIG. 3 , the bolts are connected to nuts, such as nuts 84 A and 84 B located in compartment 82 A. As depicted, pairs of bolts are spaced apart along the length of the apparatus; however, in order to fasten a cartridge to steam distributor apparatus 10 , it is not necessary that a pair of bolts be associated with each compartment.
The recess region is designed to accommodate one or more drop-out steam profiling cartridges. In the case where a single integral cartridge is employed, its length would essentially match that of the recess region. Alternatively, a plurality of shorter cartridges, which are individually inserted into the recess region and secured thereto, can be employed. The use of multiple smaller cartridges allows for selective removal for maintenance. For example, a sectioned cartridge that includes 9 steam profiling zones 82 A through 82 I is positioned in the recess region adjacent endplate 90 . Other sectional cartridges are then positioned in the recess region to form a series of sectional cartridges juxtaposed from end to end.
One benefit of employing sectional cartridges is that a fixed design unit can be more readily based-lined with conventional 3-D modeling and parameterized computer-aided design (CAD) software. Furthermore, once a design unit is dimensionally fixed, it can be used in the design of various steam distribution apparatuses. Finally, employing a drop-out steam profiling cartridge simplifies the overall design of the accompanying steambox header by reducing the number of internal channels. In particular, with comparable prior art steambox headers that accommodate removable steam profiling screens, a higher number of internal channels must be welded to the steambox headers in order to allow the removable screens to be positioned properly while maintaining the required contour of the steambox front side.
The length of steam distribution apparatus 10 typically corresponds to the width of the sheet or web to which steam is to be applied. For papermaking, the length generally ranges from 5 to 12 meters and typically is about 9 meters. Each steam profiling zone, e.g., 82 A in FIG. 3 , has a width of about 3 in. (7.6 cm) to 4 in. (10.2 cm). A typical steam distribution apparatus has up to about 90 steam profiling zones in total. In operation, the steam pressure in each profiling zone ranges up to about 80 kPa.
The foregoing has described the principles, preferred embodiments and modes of operation of the present invention. However, the invention should not be construed as being limited to the particular embodiments discussed. Thus, the above-described embodiments should be regarded as illustrative rather than restrictive, and it should be appreciated that variations may be made in those embodiments by workers skilled in the art without departing from the scope of the present invention as defined by the following claims.
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A steam distributor for applying steam to a continuously moving paper sheet employs one or more drop-out steam profiling cartridges. Each cartridge is connected to a steam distribution apparatus and includes a number of profiling zones that are covered by a contoured, smooth profiling screen from which steam is applied. The profiling screens are welded to baffles which enhances the structural integrity of the cartridge. No external clamps or other devices are employed that would otherwise disrupt the smooth, curved exterior surface of the profiling screens. The spaced-apart baffles also eliminate the spilling over of steam from one profiling zone to the next which has the effect of minimizing the response width for steam profiling control. The use of the drop-out cartridges permits quick and easy removal of the profiling screens for change-out or cleaning.
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CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority under 35 U.S.C. §119 from German Patent Application No. 10 2015 002 587.2, filed Feb. 27, 2015, the entire disclosure of which is herein expressly incorporated by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to a test system for a missile. In particular, the invention relates to a stationary test device as well as a mobile test device for a missile.
BACKGROUND AND SUMMARY OF THE INVENTION
[0003] The following abbreviations are used for describing the invention:
[0004] GNC: Guidance, Navigation and Control
[0005] NGC: Navigation, Guidance and Control
[0006] IMU: Inertial Measurement Unit
[0007] GPS: Global Positioning System
[0008] CAS: Control Actuator System
[0009] LOS: Line of Sight
[0010] VTOL:vertical take off and landing
[0011] OLED: organic light emitting diode
[0012] DoF: Degree of freedom
[0013] It is known from the prior art that, for the development of missiles, it is frequently necessary to carry out flight tests. In this case such flight tests are a cost driver in the development of missiles, which needs to be reduced in particular in order to increase competitiveness. Because of a large number of staff, as well as the required use of equipment, infrastructure and safety aspects, flight tests are associated with high financial expenditure. Especially in the initial phase of a project for missile development, the flight tests sometimes have contrary purposes. This is due to the different requirements of the various disciplines participating in development of a missile. Thus, for example, it is important for the GNC developer to be able to fly as far as possible in order to be able to test the GNC functionality for as long as possible. On the other hand, it is a concern of the image processing development to be able to fly as realistically as possible to a real target in order to obtain image data for the corresponding algorithm. The duration of flight tests is generally much too short to be able to carry out all tests. Experience shows that malfunctions also often occur, so that flight tests cannot provide evidence and therefore have to be repeated. For these reasons there are attempts to avoid flight tests and instead to replace them by laboratory tests.
[0014] In conventional “hardware in the loop” testing systems, which take place in a laboratory, rotational degrees of freedom of the missile are simulated with a turntable or a robot. In this case, the “degree of freedom” designates the number of possibilities for movement of the missile which are independent of one another. Thus, the missile has six degrees of freedom, since it is movable in three spatial directions which are independent of one another and is rotatable about three axes which are independent of one another.
[0015] However, due to the fixed construction in a laboratory it is a disadvantage that the translational degrees of freedom and all functions associated therewith cannot be tested under realistic conditions. The relative geometry between the missile and a target to which the missile is to fly must be produced artificially, which happens in the prior art for example by values of the missile calculated by simulation. These values are then artificially fed into the missile avionics instead of the actual values. As such, it is important to know the behavior of the relevant systems, such as IMU, seeker head, GPS, etc., during the flight.
[0016] In practice, it has been shown that this behavior in the real flight is often substantially different from the behavior which can be observed in the laboratory. Likewise, for optical seeker heads, the geometric conditions which are important for the entire chain of reconstruction of the line of sight and guidance of the line of sight, such as aspect angle, aspect ratio, proximity, image explosion or environmental disturbances, can only be insufficiently and artificially adjusted. If realistic data are required, for example from a seeker head, there is a possibility of carrying out carried flights on man-carrying aircraft, such as an airplane or helicopter. These carried flights are very expensive and often more expensive than real flight tests, due to the high use of resources and safety aspects. For kinematic reasons it is often not possible to achieve real translational trajectories by carried flights, particularly in the case of surface-to-surface missiles.
[0017] Furthermore, it is known from the prior art to use unmanned missiles as test objects for navigation software. For this purpose, the missile has a fixed navigation system, wherein in a standardized flight a response by the navigation software can be checked. Such a missile is known for example from DE 10 2011 115 963 B3.
[0018] An object of the invention is to provide a stationary test device as well as a mobile test device for a missile which with a simple and cost-effective production enable a safe and reliable, and thereby cost-effective, performance of tests of the missile. Finally, an object of the invention is to provide a test system consisting of the aforementioned test devices.
[0019] The object is achieved by a mobile test device for a missile comprising a flight platform, a carrier device and a control module. The flight platform is in particular an unmanned, particularly advantageously a non-man-carrying, flight platform. The carrier device is fastened to the flight platform and serves to receive an avionics testpiece of the missile. In this case the carrier device enables a movement of the avionics testpiece in three rotational degrees of freedom. The line of sight for the avionics testpiece and the relative geometry between the center of gravity of the missile and the center of gravity of the target to be approached can preferably be generated by the carrier device. The control module enables the control of the flight platform for taking off on a predetermined reference trajectory. Moreover the control module makes it possible to activate the carrier device for alignment of the avionics testpiece. Finally the navigation data produced by the avionics testpiece can be stored by the control module. Therefore a flight of the missile can be simulated by the mobile test device, wherein in particular the airspeed of the flight platform does not correspond to the airspeed of the missile. Thus, a simulation of the flight is not possible in real time, but only at a slower speed. The navigation data stored by the control module can be used particularly advantageously for the simulation with the stationary test device according to the invention.
[0020] The carrier device of the mobile test device is particularly advantageously a gimbal platform. Thus, a simple and efficient alignment of the avionics testpiece is made possible.
[0021] The flight platform is preferably a helicopter. Thus, in particular, the capability for vertical takeoff and landings is provided. The flight platform particularly advantageously has at least two horizontal oriented rotors. Since a status control is necessary for such an arrangement of rotors, the control module, as described above, preferably also performs the activation to the flight platform so that a stable flight with the flight platform is enabled by the status control performed by the control module.
[0022] Moreover, the invention relates to a test system for a missile, wherein the test system comprises a stationary test device and a mobile test device, also in particular as described above. The stationary test device comprises, in particular, a retaining device and a display device. The retaining device serves, in particular, to receive an avionics testpiece of the missile, wherein the retaining device enables a movement of the avionics testpiece in three rotational degrees of freedom. The display device serves for presentation of information on the surroundings of the missile. The display device can be moved inside a virtual plane, in particular, by a translational carriage system. Thus, the display device is movable in two translational degrees of freedom, so that two translational degrees of freedom of the missile can be simulated. In this way translational degrees of freedom of the missile perpendicular to a longitudinal axis of the missile, or a sight axis of the avionics testpiece, can be simulated. For this purpose, it is provided that the display device can be detected by the avionics testpiece if the avionics testpiece is disposed on the retaining device. If the display device is moved, as described above, a translational movement of the missile is suggested to the seeker head. The display device itself simulates a translational movement of the missile in a third direction of movement, wherein these third direction of movement is in particular oriented parallel to a longitudinal axis of the missile, or to the sight axis of the avionics testpiece. Thus, an OLED screen may be particularly provided as a display device, on which real-time information on surroundings can be displayed by a video system. In this way, a flight of the missile can be simulated realistically, so that also geometric conditions, such as aspect angle, aspect ratio, proximity, image explosion or environmental disturbances (such as change to the lighting conditions), can be simulated realistically. The synchronously required data for the avionics testpiece, such as in particular IMU data, are preferably artificially fed into the avionics testpiece.
[0023] The stationary test device preferably has a control unit. A movement of the retaining device and shifting of the display device can be controlled by the control unit. Moreover, it is preferably provided that the aforementioned video system and thus the display on the display device can be controlled by the control unit. In this way, the take-off on a pre-defined reference trajectory can be simulated, wherein the navigation data generated by the avionics testpiece can be stored by the control unit. Particularly preferably the behavior of the missile during the taking off on the reference trajectory has been simulated beforehand by the mobile test device, according to the invention, so that a realistic control of the movement of the retaining device and the shifting of the display device is made possible by the control unit of the stationary test device.
[0024] Finally, it is preferably provided that the retaining device is a turntable or a robot.
[0025] The test system is preferably characterized in that the stationary test device can be operated with simulation data which can be obtained from measurement data. In this case the measurement data can be captured during the operation of the mobile test device. Thus a, very accurate simulation is made possible by the stationary test device.
[0026] Particularly advantageously it is provided that the simulation data which can be obtained from the measurement data received during of the operation of the mobile test device comprise IMU data, GPS data, CAS data and seeker head data.
[0027] Finally, the invention relates to a method for testing missiles, in particular with a test system, as described above. A method according to the invention comprises the following steps: First of all a reference trajectory, in particular a three-dimensional and/or translational reference trajectory, is defined. The reference trajectory preferably simulates a relative geometry between the missile and a target to which the missile should fly. In the next step the take-off on the reference trajectory takes place with a mobile test device. In this case it is provided that an avionics testpiece of the missile is disposed on the mobile test device. Navigation data generated by the avionics testpiece during the take-off on the reference trajectory are particularly advantageously recorded. In a last step a simulation of a movement of the missile takes place with a stationary test device. In this case, the avionics testpiece is disposed on the stationary test device. The simulation takes place with reference to simulation data which are based on the measurement data obtained during the take-off on the reference trajectory with the mobile test device. Thus, a very accurate simulation of the missile is possible, so that a plurality of flight tests can be simulated in advance by the stationary test device.
[0028] Further details, advantages and features of the present invention are apparent from the following description of exemplary embodiments with reference to the drawings. In the drawings:
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] FIG. 1 shows a schematic overall view of a development process for development of missile avionics,
[0030] FIG. 2 shows a schematic overall view of a test system according to one exemplary embodiment of the invention,
[0031] FIG. 3 shows a schematic representation of a mobile test device according to an exemplary embodiment of the invention,
[0032] FIG. 4 shows a schematic representation of a stationary test device according to an exemplary embodiment of the invention.
DESCRIPTION OF PREFERRED EMBODIMENTS
[0033] FIG. 1 shows schematically an overview of a product development process of a missile, wherein, starting from an idea 100 , a finished product 113 is to be achieved. In this case the definition of requirements 101 takes place in a first step. Then the model design 102 takes place. Next, the designing of the NGC algorithm 103 is carried out so that a simulation analysis 104 can be carried out in a further step. Then, the validation process 105 takes place. If, in a results check 106 , the results of this validation process 105 are unsatisfactory, an iterative process takes place by selecting the steps already carried out of model design 102 and designing of the NGC algorithm 103 with subsequent simulation analysis 104 , validation process 105 and results check 106 . This lasts until satisfactory results of the results check 106 are available.
[0034] As soon as satisfactory results are available from the validation process 105 , the validation of the software code 107 as well as the designing of the avionics 108 takes place. After the designing of the avionics 108 an avionics validation 109 must take place, wherein after the avionics validation 109 has been carried out the validation process 105 is invoked again.
[0035] At the same time, after the avionics validation 109 a verification of the entire system 110 takes place, which likewise leads to the selection of the validation process 105 . Then the validation of the entire system 111 takes place, wherein it is likewise possible to return to the validation process 105 . Thus, it can be seen that the entire development progress can include a large number of iterations, wherein for the validation process 105 often a plurality of flight tests of the missile often have to be carried out. Should the validation of the entire system 111 proceed successfully, then by means of the quality control 112 the finished product 113 is achieved.
[0036] The present invention starts at the step of avionics validation 109 , in order here to reduce the plurality of flight tests and in order to be able to simulate a maximum number of tests already in a laboratory. In this case it is provided in particular that laboratory tests can also be carried out in addition to flight tests, so that results obtained by simulation can be confirmed by real tests.
[0037] FIG. 2 shows schematically an overall view of a test system according to one exemplary embodiment of the invention. The test system 16 is also designated as an integrated 6DoF testbench 16 , wherein the abbreviation DoF signifies “degree of freedom”, and indicates the number of degrees of freedom in which a simulation is possible is.
[0038] Moreover, it can be seen from FIG. 2 how the test system 16 co-operates with a generic avionic design tool 19 , 20 . The term “Generic Avionic Design Tool (GADT)” should be understood as an umbrella term of a software and hardware toolbox which has been applied for the rapid prototyping and for the rapid qualification of flight management systems in the field of missiles. It covers the most varied hardware and software tools which all interrelate. Thus the avionics and the equipment of a missile can be very efficiently tested, graphically represented, evaluated and documented. The Generic Avionic Design Tool 19 , 20 is not the subject of this invention.
[0039] The integrated 6DoF testbench 16 is a new hardware and software component of the Generic Avionic Design Tool toolbox 19 , 20 and is a tool for the previously described step “Avionics Equipment & NGC Subsystem Validation”, i.e. the step of avionics validation 109 . From the GADT toolbox 19 , 20 , the “GADT Algorithm Design Library” and the “GADT Algorithm Design Environment”, which in FIG. 2 are combined as the first GADT 19 , are also used for this step. With these two tools the 6DoF of movement of the missile are calculated for a relevant test scenario by simulation and are then supplied by means of a ground station to a flight platform 11 , in particular a VTOL platform, which then takes over the synchronization between a translational position and an associated location of the avionics testpiece 3 . The precise mode of operation is described below with regard to FIGS. 3 and 4 .
[0040] Likewise from the GADT toolbox 19 , 20 the GADT-Debug & Telemetry System is used in order to capture and store the relevant test data from the avionics testpiece 3 . The GADT Postflight Simulation & Validation Tool which is shown in FIG. 2 as second GADT 20 is used in the validation process.
[0041] Overall, therefore, after calculation of a reference trajectory 21 by the first GADT 19 it is possible with the test system 16 to carry out flight tests which are divided into carried flight tests with the mobile test device 2 and simulations with the stationary test device 1 . The first test data 22 thus obtained by the mobile test device 2 and the second test data 23 obtained by the stationary test device 1 can therefore be used in the validation process with the second GADT 20 .
[0042] In connection with missile systems or sub-systems the term “validation and verification” is used in the following context:
A verified real system/sub-system is a system in which it has been demonstrated that the system behaves in an error-free manner with regard to its prescribed specification. (Is the system correctly constructed?) A verified synthetic model of a reference-system/model is a model which behaves in an error-free manner and in the same manner on a signal plane relative to the reference system/model. (Is the model correctly constructed? Does it behave like the reference system/model? Whether the reference system is validated is not important.) A validated real system/sub-system is a system in which it has been demonstrated that in its actual operational environment the system corresponds to the prescribed requirements. (Is the system functioning correctly?) A validated synthetic model is a model which on the signal plane behaves in a sufficiently similar manner to the validated real system. (In this case the verification of the synthetic model is a basic prerequisite.)
[0047] The integrated 6DoF testbench 16 consists essentially of two parts, the mobile 6DoF testbench 2 and the stationary 6DoF testbench 1 .
[0048] With the mobile 6DoF test bench 2 it is possible, without the substantial expenditure on staff, safety requirements, infrastructure, etc., to repeatedly carry out cost-effective carried test flight in a realistic environment. In this case measurement data 17 are recorded, which then serve in the laboratory as simulation data 18 and can be analyzed in any way with the stationary 6DoF testbench 1 .
[0049] Due to the cost-effective reproducibility of the carried flights, on the one hand the conflict described in the introduction of the different requirements and the temporal limitation is resolved in the case of flight tests and supplies data for all requirements. On the other hand, with the integrated 6DOF testbench 16 complex NGC functionality can be tested in order thus to reduce failures in test flights. In particular it is provided that the integrated 6DoF testbench 16 does not replace flight tests, but complements the conventional validation through flight tests.
Mobile 6DoF Testbench 2
[0050] First of all, the mobile 6DoF testbench 2 is described. The flight should take place with a flight platform 11 , in particular with a VTOL carrier platform on which an avionics testpiece 3 is disposed, on a 3DoF reference trajectory 21 which is determined and programmed by the first GADT 19 .
[0051] The flight platform 11 preferably comprises two rotors 14 which are offset and horizontally oriented, so as to provide a suitability for vertical takeoff and landing. The avionics testpiece 3 is in particular disposed centrally between the two rotors 14 . The flight platform 11 generates the line of sight for the avionics testpiece and the relative geometry between the center of gravity of the missile and the center of gravity of the target to be approached.
[0052] The reference trajectory 21 is prepared and transmitted by a ground and control station (not shown) for the flight platform 11 , in particular the VTOL carrier platform. The 3DoF reference trajectory 21 simulates the real relative geometry between the missile and a target to be approached. The flight platform 11 , in particular the VTOL carrier platform, has a carrier device 12 , in particular a 3DoF rotary gimbal platform, in which the avionics testpiece 3 is rotatable is in three degrees of freedom. Thus it is possible to image the actual encounter geometry of a missile in six dimensions in real surroundings. Because of speed restrictions in the flight platform 11 , in particular the VTOL carrier platform, the reference trajectory 21 is not flown in real time.
[0053] Compliance with the reference trajectory 21 and the temporal co-ordination between position and associated location of the avionics testpiece 3 is performed by a control module 13 . In order to be able to store the real test data from the avionics testpiece 3 in the test flight, the control module 13 has a data logger and a measuring module. All of the power required for driving the rotors 14 and for operating the control module 13 , the carrier device 12 and the avionics testpiece 3 is provided by a power module 15 . The power module 15 , just like the control module 13 , is disposed on the flight platform 11 . In particular the power module 15 comprises an accumulator or a battery for storing electrical power.
[0054] The ground and control station (not shown) is the interface for communication purposes between a person operating the mobile test device 2 person and the flight platform 11 . It serves to exchange data relating to the flight platform 11 via an up-down link data to interchange and to provide this graphically for the operator. These data serve for controlling and monitoring the flight platform 11 .
[0055] The control module 13 images the functioning of the flight state control for the flight platform 11 in order to fly on any trajectory, in particular on the reference trajectory 21 . Moreover the control module 13 controls the temporal co-ordination between position and location of the avionics testpiece 3 . The location is then transmitted as a command to the carrier device 12 and converted, in particular as a gimbal angle. The data logger and the measuring module as a real-time measuring system receive all relevant measurement data of the avionics testpiece 3 in real time on and store these data. In this way the aforementioned measurement data 17 are obtained.
[0056] The carrier device 12 , in particular the 3D rotary gimbal platform, forms both the mechanical and also the electrical interface between the avionics testpiece 3 and the flight platform 11 . The object of the carrier device 12 is to image the location of the avionics testpiece 3 , which would occur in the real approach of the missile to be simulated. The location of the avionics testpiece 3 is calculated in advance for the respective test case of the first GADT 19 and delivered to the control module 13 via the ground and control station. The temporal co-ordination and control of the carrier device 12 , in particular the rotary gimbal platform, is undertaken by the control module 13 .
[0057] The mobile 6DoF testbench has the following main objectives:
Qualification/validation of image processing & NGC sub-functions, in particular of seeker head & IP & image processing, of the navigation system and of guidance & control Equipment data acquisition for further processing in the stationary 3DoF testbench 1 and subsequent validation, in particular the seeker head data recording of a real approach (video, IP, SAL) to assist the algorithm development (FoV problems, timing, image processing, . . . ), the IMU data recording, and the GPS data recording
Stationary 6DoF Testbench 1
[0060] FIG. 4 shows schematically the stationary test device 1 according to an exemplary embodiment of the invention, wherein the stationary test device 1 is also referred to as the stationary 6DoF testbench 1 .
[0061] The three rotational degrees of freedom of the missile with a retaining device 4 , in particular with a 3DoF turntable, are simulated in reality by the stationary 6DoF testbench 1 . The two translational degrees of freedom transversely with respect to the line of sight, in particular transversely with respect to a longitudinal axis of the missile, are imaged in reality by a 2DoF translational carriage system 6 .
[0062] The last translational degree of freedom, the approach to the line of sight, in particular of the longitudinal axis of the missile, and the geometric conditions which can be varied thereby such as aspect angle, aspect ratio, proximity, image explosion, or environmental disturbances such as background, lighting conditions, etc., are displayed in real time by a video system on a display device 5 , in particular on an OLED screen. The data required synchronously for the avionics testpiece 3 , such as in particular the IMU data, are artificially fed into the avionics testpiece 3 . Realistic simulation data 18 are obtained from the measurement data 17 which have been previously acquired by the mobile 6DoF testbench 2 . All relevant data, in particular navigation data, from the avionics testpiece 3 are recorded by a control unit 7 and are compared with other test data and validated in the post-flight simulation. For recording of the navigation data of the avionics testpiece 3 , this testpiece is connected by a data line 10 to the control unit 7 .
[0063] For simulation of a flight, the control unit 7 can control the retaining device 4 via a first control line 8 and can control the carriage system 6 via a second control line 9 . In particular the control takes place by means of analogue signals. The control of the retaining device 4 and of the carriage system 6 is based on the simulation data 18 obtained from the real measurement data 17 . Thus the movement of the avionics testpiece 3 corresponds to a realistic simulation of a flight of the missile.
[0064] The stationary 6DoF testbench 1 has the following main objectives:
Verification of image processing algorithms Verification of LOS estimation Tuning of LOT synchronization IMU/seeker head synchronization LOT performance & problems (timing, stability, . . . ) LOS decoupling Boresight error estimation and performance
[0072] The test system 16 , in particular the mobile test device 2 and the stationary test device 1 , enable the complete relative geometry and encounter geometry in 6 degrees of freedom of any missile in “slow motion” to be generated in reality by comparison with a stationary target to generate. This is not possible with conventional testing systems for missiles.
[0073] Moreover, already before the first flight test open loop as well as closed loop the entire avionics (IMU, seeker head, gimbal, navigation, image processing, . . . ) can be tested and functionalities can be validated in reality.
[0074] The invention represents a validated modular avionics sensor system: In advance of future development projects different seeker head-IMU-NGC design can be tested and validated under realistic operating conditions and independently of their future carrier-based missile.
[0075] Moreover, flight tests can be supplemented and problems in the algorithms or the avionics-sensor combination can be identified at an early stage. The flight tests can be repeated multiple times for data recording and reproduced for post-flight analysis.
[0076] Because of the availability of realistic data both the NGC algorithms and also the image processing algorithms can be developed and optimized better than is possible in the prior art.
[0077] Finally the invention offers a high savings potential, because expensive flight tests with real missiles can be reduced, as well as a considerable technical minimization of risk.
[0078] In addition to the foregoing written description of the invention, in order to supplement the disclosure thereof reference is hereby made to the drawings representing the invention in FIGS. 1 to 4 .
LIST OF REFERENCE NUMERALS
[0079] 1 stationary test device
[0080] 2 mobile test device
[0081] 3 avionics testpiece
[0082] 4 retaining device
[0083] 5 display device
[0084] 6 carriage system
[0085] 7 control unit
[0086] 8 first control line
[0087] 9 second control line
[0088] 10 data line
[0089] 11 flight platform
[0090] 12 carrier device
[0091] 13 control module
[0092] 14 rotor
[0093] 15 power module
[0094] 16 test system
[0095] 17 measurement data
[0096] 18 simulation data
[0097] 19 first GADT
[0098] 20 second GADT
[0099] 21 reference trajectory
[0100] 22 first test data
[0101] 23 second test data
[0102] 100 idea
[0103] 101 requirements
[0104] 102 model design
[0105] 103 NGC algorithm design
[0106] 104 simulation and analysis
[0107] 105 validation process
[0108] 106 results check
[0109] 107 validating software code
[0110] 108 avionics design
[0111] 109 avionics validation
[0112] 110 verification of the entire system
[0113] 111 validation of the entire system
[0114] 112 quality control
[0115] 113 finished product
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A stationary test device for a missile includes a retaining device for an avionics testpiece of the missile, where the retaining device enables a movement of the avionics testpiece in three rotational degrees of freedom, and a display device configured to display information on the missile surroundings, where the display device is configured to be moved inside a virtual plane by a translational carriage system. The display device can be detected by the avionics testpiece if the avionics testpiece is disposed on the retaining device. A mobile test device for the missile includes a flight platform, a carrier device mounted on the flight platform, for an avionics testpiece of the missile, wherein the carrier device enables a movement of the avionics testpiece in three rotational degrees of freedom, and a control module, where the control module is configured to control the flight platform for taking off on a specified reference trajectory, control the carrier device for orientation of the avionics testpiece, and store navigation data generated by the avionics testpiece. Finally, a test system for the missile includes the stationary test device and the mobile test device.
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FIELD OF THE INVENTION
The present invention relates to elongated textile elements of nodular appearance, processes for their manufacture and the articles produced using these elements.
DISCUSSION OF PRIOR ART
It is known, in the textile industry, to produce yarns, which may be continuous yarns or spun fibres, having a nodular appearance, that is to say exhibiting more or less widely spaced nodules over their length. These fancy yarns are used for producing woven fabrics or knitted fabrics employed in garments and in furnishing (curtains, tapestries, wall coverings, seat covers and the like).
U.S. Pat. No. 3,129,485 (Shattuck, et al.) relates to a process and apparatus for making regularly or irregularly bulky yarns in which the yarns are individually treated by an air jet.
U.S. Pat. No. 3,284,871 (Yano, et al.) relates to intermittently crimped filaments and the method of their production.
However, the use of these yarns is restricted by the fact that they have a low diameter and the process and apparatus for their production are complicated.
A new textile element of very decorative nodular appearance, the processes of manufacture of which is simple to carry out, has now been found.
Accordingly, the invention relates in one aspect to elongated textile element of nodular appearance, which consists of an assembly of substantially parallel yarns of high bulk, which exhibits, over its length, at least two compressed zones of relatively low diameter separated by a bulky zone of relatively high diameter.
According to one embodiment, the simplest textile element is in the form of a single nodule with two compressed zones located at the two ends and separated by a bulky zone of high apparent diameter. In another embodiment, the textile element can also comprise a succession of compressed zones of identical or non-identical length, distributed along the assembly in a regular or irregular manner, but over its entire thickness. These can be obtained, for example, by simple tieing of the assembly by means of a ring or other tubular means, which may be slidable, and may be made of any textile material, for example a heat-shrinkable yarn, metallic material, wood, plastic, paper, and the like, or can be obtained by applying a curable binder, a wire or any other similar means, by heat-welding, by simple interlacing of yarns, and the like. The bulky zones located between the compressed zones are in the shape of a nodule, of identical or different diameters, and the length of these zones can be less than, greater than or equal to that of the compressed zones.
According to the second aspect, the invention relates to a process for obtaining the abovementioned textile element, which is characterized in that an assembly of substantially parallel yarns of high bulk is placed under tension, compressed zones are created over the entire thickness of the assembly, intermittently over its length, and the tension is relaxed.
Another embodiment of a process according to the present invention, which is particularly valuable if yarns having a latent crimpability are used, is characterized in that yarns having a latent crimpability are assembled in parallel, compressed zones are created over the entire thickness of the assembly and intermittently over its length, and the yarns are subjected to a crimp-developing treatment.
The process described above provides a textile element exhibiting a succession of nodules. The assembly can thereafter be cut at the position of the compressed zones so as to separate off one or more nodules.
The textile element according to the invention is particularly valuable for the manufacture of garments or of furnishing articles, for example for the manufacture of curtains, tapestries, partitions, various wall coverings, lampshades and the like, because it exhibits a very marked decorative effect. It can be used by itself, for example to form a woven fabric of loose construction which can be used for garments, or in association with other materials such as wood, plastics, other textiles and the like. The textile elements possessing a single nodule make it possible to obtain a great variety of articles because there are numerous possible ways of assembling such elements. It is possible to use nodules of different colors and of different sizes, to thread them up, like beads, on any carrier (a metal wire or plastic thread), or to glue them by their ends, or by a part of the bulky zone, into a support, so as to obtain very decorative textile surfaces.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a single-nodule textile element according to the present invention;
FIG. 2 shows a textile element having a plurality of compressed zones and the bulky (nodular) zones; and
FIG. 3 shows a decorative curtain formed from a series of textile elements such as shown in FIG. 2.
DETAILED DESCRIPTION OF THE INVENTION
As used in the present specification and claims, the term "yarns of high bulk" are to be understood to include both continuous filaments and discontinuous fibers which possess a low density and a high apparent volume, and are based on any starting material of natural, artificial or synthetic origin, it being possible for the discontinuous fibers to be in the form of roving, sliver or spun yarns, while the continuous filaments can be in the form of tows or be wound together, these forms being used separately or in combination.
The high bulk yarns used are generally yarns which, in the finished textile article, are crimped, the crimp being produced either before or at the last stage of manufacture of the textile article of the invention. The yarns which have been crimped before the manufacture of the article can be obtained by a great diversity of processes. Among these there may be mentioned twisting processes, for example the conventional bulking process, the false twist process, the set false twist process and the like, mechanical or pneumatic processes, processes of deformation by passing over a blade together with heat treatment, by hot drawing over a gearwheel, or by knitting and unknitting (the K.D.K. process), and processes involving looping by means of compressed air jets; "high bulk" type spun yarns wherein the fibers have different shrinkages, and, finally, composite yarns of the two-layer type, obtained by spinning two synthetic polymers of different chemical constitution, are also suitable.
The yarns of which the crimp is developed at the last stage of manufacture of the article according to the invention are yarns which possess a latent crimpability, and of which the crimp is developed by a heat treatment or chemical treatment. As examples of these types of yarns there may be mentioned composite yarns of the two layer type, or mixtures of shrinkable fibers (based on vinyl chloride) and non-shrinkage fibers all of which are well known in the art.
The textile articles which possess a succession of several nodules are particularly valuable for the manufacture of tapestries and insulating partitions or decorative partitions, because it suffices to cut the elements to the desired length and to attach them at one or both ends to a rigid element.
Where slidable elements, for example rings, are used as the means for compression, it can be of value to vary the dimensions of the nodules at will. Furthermore, it should be indicated that since the textile element is relatively simple to manufacture, a non-specialist would be able to produce by himself, and to suit his taste, a decorative article from an assembly of high bulk yarns and simple means of compression such as wooden beads, adhesive tapes, or simple ligatures employing a textile tie.
FIG. 1 shows a single-nodule textile element consisting of an assembly 1 of substantially parallel yarns and possessing a bulky zone 2 and two zones 3 which are compressed by means of clamping rings 4.
FIG. 2 shows a textile element consisting of a series of nodules 2 between compressed zones 3.
In FIG. 3, a plurality of multi-nodular textile elements are each attached at one end thereof, corresponding to a compressed portion of the element, to a rigid or fixed member whereby the elements for a decorative partition or panel. For example, by attaching a series of the elongated textile elements of the present application to the overhead cross piece of a doorway or to the ceiling or beam between two sections of a room, an attractive room divider can be obtained. Of course, the elements can be fixed at both ends, such as upon a wall to form a decorative panel.
Although the lengths and apparent diameters of the compressed zones 3 and bulky zones 2 are not critical with respect to the decorative effects of the elongated textile elements, it is preferred that the ratio between the apparent diameter, i.e. the diameter under relaxed conditions of the compressed zone and bulky zone is within the range of from 2 to 1 to about 50 to 1.
The number of used high bulked yarns to form nodular appearance of the textile elements, and the device of these yarns depend of the presentation of the yarn as explained above and on the intended application.
The present application will now be described in further detail by the following illustrative examples which are intended as representative of and not limiting the scope of the present invention.
EXAMPLE I
A bundle is formed from 40 continuous yarns of polyhexamethylene adipamide each of gauge 2,800 dtex (2,500 den)/136 strands and of unbleached white color, the yarns having been texturized by pneumatic means such as those described in U.S. Pat. No. 3,482,294; this bundle is then placed under tension, and pinched zones are then created by wrapping with a pink yarn of the same constitution, the turns being placed side by side, sometimes over a length of three centimeters and sometimes over a length of five centimeters. The tension is then relaxed; and elongated textile element such as that shown in FIG. 2 is obtained. Several of these elements, placed side by side and held at the same end produce a curtain-type panel (see FIG. 3) which can be placed in front of a window or fixed, as a decorative element, to a wall or form a room divider.
EXAMPLE 2
A tow of 480 two-layer yarns each of 400 dtex (360 den), which are crimped and are made from a polymer consisting of 50% of poly(ethylene terephthalate) cross-linked with 0.65 mol% of trimethylol propane and 50% of poly(butylene terephthalate) crosslinked with 0.3 mol% of trimethylol propane, is made up; it is placed under tension and rings formed of colored plastic tubes of different colors and lengths are then threaded into this tow and arranged irregularly along the said stretched tow. Thereafter the tension is relaxed. Several of the elements obtained are joined side by side as in Example 1 to form a panel which can be placed in front of a window or fixed to a wall as a decorative element. It should be noted that the effect obtained can be varied by using slidable rings.
EXAMPLE 3
A yarn of poly(ethylene terephtahalate) of 1,100 dtex (1,000 den) formed by assembling 200 filaments and texturized by pneumatic means such as are described in U.S. Pat. No. 3,482,294 is placed under tension. Compressed parts of two centimeters length, spaced at intervals of 12 centimeters, are created in the yarn by depositing a neoprene glue. The glue is allowed to dry in air for 5 minutes and the tension is then relaxed. The element obtained is woven in a plain weave so as to give a furnishing fabric having a very decorative appearance.
EXAMPLE 4
A yarn of poly(hexamethylene adipamide) of 2,800 dtex (2,500 den), formed by assembling 136 filaments, and texturized by pneumatic means such as those described in U.S. Pat. No. 3,482,294 is kept in the tensioned state. Compressed zones of about 1.5 centimeters, spaced at intervals of 10, 5 and 25 centimeters, are created by means of a pneumatic knotting gun. Several elements thus obtained are glued side by side, by means of neoprene glue, onto a paper web. A very decorative texturized wall covering is obtained.
EXAMPLE 5
A spun yarn of metric number 6, and coefficient of twist 50 is produced; it consists of 80% of wool fibers of mean length 80 mm and 20% of fibers obtained by spinning a mixture of polyvinyl chloride and chlorinated polyvinyl chloride (in the ratio 80/20), trademark CLEVYL F, which fibers have a shrinkage of 35% in boiling water, an elongation at break, in the shrunken state, of 60% and lengths ranging from 60 to 100 mm. After spinning, three ends of this spun yarn are twisted together in the opposite direction to that of the spinning twist, so as to reduce the degree of twist (coefficient of twist 42).
Four yarns thus obtained are assembled and held under tension. Compressed zones are created every 2, 4 and 10 centimeters by means of a metal spiral. The assembly is treated in an oven containing steam at 105° C. so as to cause the shrinkage of the vinyl fibers and cause the bulking-up of the non-compressed zones.
The textile element obtained is used as in Example 1 for the manufacture of a wall hanging which in addition to its decorative appearance has the advantage of exhibiting good fire resistance.
EXAMPLE 6
350 crimped composite yarns of the two-layer type, each of 500 dtex (450 den), the yarns being crimped and made of a polymer consisting of 50% of poly(ethylene terephthalate) crosslinked with 0.65 mol% of trimethylolpropane and 50% of poly(butylene terephthalate) crosslinked with 0.3 mol% of trimethylolpropane, are assembled. Compressed zones located every 4 and 12 centimeters are created on the assembly, which is kept in the tensioned state, by means of a heat-shrinkable tubular jersey fabric produced with a vinyl chloride-based yarn, which is then heat treated at 110° C. The textile element obtained is used as in Example 1 for the manufacture of a decorative wall hanging.
EXAMPLE 7
A yarn of 2,400 dtex (2,150 den), formed by assembling 1,200 two-layer filaments made from a polymer consisting of 50% of poly(ethylene terephthalate) crosslinked with 0.65 mol% of trimethylolpropane and 50% of poly(butylene terephthalate) cross-linked with 0.3 mol% of trimethylolpropane, is kept in the tensioned state. It is ligatured every 7 and 12 centimeters, without making a knot, with a coil of a heat-fusible yarn consisting of a terpolymer of hexamethylene sebacamide, para-aminocyclohexylmethane adipate and caprolactam. The yarn is passed through an air jet, the air being heated to 130° C., to cause the heat-fusible yarn to melt and to develop the crimp of the two-layer yarn. The textile element obtained is used as in Example 1 to manufacture a decorative panel.
Having described certain representative embodiments and details for purpose of illustrating the present invention, it will be apparent to those having skill in this art that various changes and modifications can be made without departing from the spirit and scope of the invention defined in the appended claims.
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The invention relates to elongated textile elements having one or more thickened portions along its length, processes for their manufacture and the articles produced with such elements.
The element is characterized in that it consists of an assembly of substantially parallel yarns of high bulk, which possesses, over its length, at least two compressed zones of low diameter separated by a bulky zone of high diameter.
These elements, used by themselves or in association with other materials, make it possible to obtain very decorative articles suitable for garments and especially for furnishings such as tapestries, wall coverings, seat covers and the like.
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BACKGROUND
[0001] The invention relates to virtual environment systems, and more particularly to a method for optimizing the storage allocation in a virtual desktop environment.
[0002] Computer virtualization has become one of the more important technologies for different sized companies. Computer virtualization increases the computational efficiency and flexibility of a computing hardware platform. Using, in particular, storage virtualization in a virtual desktop environment is also becoming a critical part of business computing in these companies.
[0003] In a Virtual Desktop environment, the local file system assigned for each desktop is a chunk of dedicated virtualized storage taken from a physical storage pool. Each time a user saves a file to his/her file system, a copy of this file is stored on the dedicated chunk of physical storage for that desktop. In the case where several virtual desktop users, belonging to the same business context, are saving the same file to their file system, the result is that several copies of that same file are likely to be stored on the common physical storage. This redundancy causes unnecessary usage of extra storage, thereby making it necessary to acquire larger storage volumes than actually required.
[0004] Another problem related to the usage of other state of the art systems is that the users have to use a predefined or shared directory tree structures and are not able to store their files in a user-specified location. The users of such systems are also not able to modify the directory structure of the shared storage volume as this would confuse other users assuming their files to be still available via the original file path.
SUMMARY
[0005] It is an objective of embodiments of the invention to provide for an improved computer-implemented method, data processing system and corresponding computer-readable storage medium. Said objective is solved by the subject matter of the independent claims. Advantageous embodiments are described in the dependent claims.
[0006] The term “virtual desktop” as used herein is a virtual machine physically located in a data storage managed by a virtual desktop environment. In particular, the virtual desktop may be provided by the virtual desktop environment running on a server instead of on the local storage of a client. Thus, according to some embodiments, when users work from their local client machines, all the programs, applications, processes and data used are kept on the server and are run centrally. Desktop virtualization allows users to run operating systems and applications from a smartphone or from any other form of thin client having limited hardware resources. According to some other applications and embodiments, the virtual desktops may be loaded temporarily into the working memories of the client devices while any modification of data is persisted only in storage volumes managed by the server.
[0007] The term “computer-readable storage medium,” as used herein encompasses any tangible storage medium which may store instructions which are executable by a processor of a computing device. The computer-readable storage medium may be referred to as a computer-readable non-transitory storage medium. The computer-readable storage medium may also be referred to as a tangible computer readable medium. In some embodiments, a computer-readable storage medium may also be able to store data which is able to be accessed by the processor of the computing device. Examples of computer-readable storage media include, but are not limited to: a floppy disk, punched tape, punch cards, a magnetic hard disk drive, a solid state hard disk, flash memory, a USB thumb drive, Random Access Memory (RAM), Read Only Memory (ROM), an optical disk, a magneto-optical disk, and the register file of the processor. Examples of optical disks include Compact Disks (CD) and Digital Versatile Disks (DVD), for example CD-ROM, CD-RW, CD-R, DVD-ROM, DVD-RW, or DVD-R disks.
[0008] The term computer readable-storage medium also refers to various types of recording media capable of being accessed by the computer device via a network or communication link. For example data may be retrieved over a modem, over the internet, or over a local area network. References to a computer-readable storage medium should be interpreted as possibly comprising multiple computer-readable storage mediums. Various executable components of a program or programs may be stored in different locations. The computer-readable storage medium may for instance comprise multiple computer-readable storage medium within the same computer system. The computer-readable storage medium may also be computer-readable storage medium distributed amongst multiple computer systems or computing devices.
[0009] The term “metadata repository” as used herein encompasses a storage medium or part thereof having stored metadata. For example, the metadata repository may be implemented as a database system being designed to support the storage, use and retrieval of metadata by a processor. Metadata may include, for example, information about how to access specific data, or more detail about said data.
[0010] The term “application programming interface (API)” as used herein refers to an interface that software programs implementing said interface use to interact with each other; much in the same way that software might implement a user interface in order to allow humans to interact with it. APIs are implemented by software applications (SAs), libraries and operating systems to define how other software can make calls to or request services from them. An API determines the vocabulary and calling conventions that the programmer should employ in order to use the services. It may include specifications for routines, data structures, object classes, and protocols used to communicate between a consumer and an implementer of the API.
[0011] The term “access control list (ACL)” as used herein refers to an indication, in any security framework (e.g., access control framework, mandatory access control framework, discretionary access control framework, lattice based access control framework, etc.), of users and/or groups of users permitted access to a file. According to embodiments, the level of permitted access (e.g., read-only, read-write, delete, etc.) may also be indicated in the access control list.
[0012] The term “computer memory” or “memory” is an example of a computer-readable storage medium. Computer memory is any memory which is accessible by a processor. Examples of computer memory include, but are not limited to: RAM memory, registers, and register files. In some instances a computer memory may also include: a hard disk drive, a floppy drive or a solid state hard drive. For instance, part of a memory may in fact be swap space on a hard drive. References to “computer memory” or “memory” should be interpreted as possibly comprise multiple memories. The memory may for instance comprise multiple memories within the same computer system. The memory may also comprise multiple memories distributed amongst multiple computer systems or computing devices.
[0013] The term “processor” as used herein encompasses an electronic component which is able to execute a program or machine executable instruction. References to the computing device comprising “a processor” should be interpreted as possibly containing more than one processor or processing core. The processor may for instance be a multi-core processor. A processor may also refer to a collection of processors within a single computer system or distributed amongst multiple computer systems.
[0014] In one aspect, the present invention relates to a method for optimizing storage allocation in a virtual desktop environment, the virtual desktop environment managing a shared storage capacity, wherein the shared storage capacity is operable to store one or more first files, each stored first file being associated with a respective unique first file identifier, the virtual desktop environment providing at least one virtual desktop to a processing device of a user. The method comprises:
receiving a first write request for writing a second file specified in the request; determining a second file identifier of the specified second file; comparing the second file identifier with the first file identifier of any first file stored to the shared storage capacity; when the second file identifier is identical to one of the first file identifiers, creating a pointer to the stored first file associated with that first file identifier; and when the second file identifier is not identical to anyone of the first file identifiers, storing the specified file associated with the second file identifier in the shared storage capacity, wherein the second file identifier is stored as a further first file identifier and the second file is stored as a further first file, and creating the pointer to the stored further first file.
[0020] This illustrative embodiment may be advantageous because the method prevents storage of identical files in the shared storage capacity and also allows different users to access the same stored file. This not only conserves, in a pro-active manner, storage space, but also to improves storage performance. This is in contrast to a post-storage de-duplication method which only acts when the files are already duplicated on the storage area.
[0021] According to another illustrative embodiment, the pointer is created in a local file system of the virtual desktop. The local file system may be stored in a user-private storage area which is accessible only by the user. According to another illustrative embodiment, the first write request is received from the at least one virtual desktop, and the pointer is created in the local file system of the virtual desktop.
[0022] According to another illustrative embodiment, the method further comprises receiving a specification of a path within the local file system of the at least one virtual desktop from the user of the at least one virtual desktop. The pointer is created at a location within the local file system indicated by the specified path. According to some illustrative embodiments, the user may specify the path via a GUI element, e.g., a file selector, allowing the user to navigate within an existing local file system directory tree. Thus, contrary to some state of the art systems, a user is allowed to specify a file path in his/her own local directory and does not have to remember and accept a predefined shared file directory structure. In addition, the duplication of the files being stored in the shared storage capacity is avoided.
[0023] Such illustrative embodiments may be advantageous in that the user requesting to write a file in a specific folder of his virtual desktop will see that the file has been created with the desired characteristics on the local file system (e.g., filename, folder location, etc.) although in reality, the local file system will only have a link to the actual physical file that it is stored on the shared storage capacity. According to some illustrative embodiments, the local file system of the user is stored in a user-private storage medium of the user. The user-private storage is also managed by the virtual desktop environment.
[0024] According to another illustrative embodiment, the first and/or second file identifier is a file Cyclic Redundancy Check number, Hash number, SHA-1 or MD5 of the respective file associated with the identifier. This may have the advantage of providing a robust method to calculate a unique identification number, such that different files have different identifiers. This allows checking whether the file being requested for storage is or is not one of the previously stored files on the shared storage capacity.
[0025] According to another illustrative embodiment the method further comprises: upon storing any of the first files and upon storing the second file in the shared storage capacity, associating the first and/or second file with an access control list comprising user IDs of all users having access to the stored first or second file. In addition, or alternatively, upon storing any of the first files and upon storing the second file in the shared storage capacity, the method comprises associating the stored file with a reference count representing the number of users having access to the stored first or second file. This illustrative embodiment may be advantageous because it ensures a secure and controlled access to the stored files, since they are protected by allowing access only to the users whose user IDs are indicated in the access control list.
[0026] According to some illustrative embodiments, only user IDs of users allowed to access a stored file are contained in the file access list of the stored file. Another advantage may be that the number of users having access to a stored file is simply obtained by reading a reference count which is a single number. This is a faster process than reading and deriving such number from the access control list of the stored file by, for example, counting the number of users identified in the access control list.
[0027] According to another illustrative embodiment, the method further comprises receiving a delete request from the user. The delete request is indicative of one of the first files. Upon having received the delete request, the user ID of the user having submitted the delete request is deleted from the access control list of that file indicated in the delete request. According to another illustrative embodiment, in this case the reference count is decremented in addition to removing the user ID. This ensures that the access control list and the reference count keep representing the exact number of users having access to the file. According to another illustrative embodiment, in this case the pointer of that file stored in the local file system of the user's virtual desktop is deleted as well. Also, if the reference count is equal to zero, the file is deleted from the shared storage capacity.
[0028] According to another illustrative embodiment, the step of storing the specified second file further comprises the steps of: creating the access control first and/or the reference count for the specified second file; and adding the user ID to the access control list and/or incrementing the reference count. According to another illustrative embodiment, the step of creating the pointer comprises adding the user ID to the access control list of the file the pointer is directed at and/or incrementing the reference count.
[0029] According to another illustrative embodiment, the method further comprises: receiving a second write request for writing the second file; creating a second pointer to the existing first file having been stored in response to the first write request, the second pointer being created in the local file system of the virtual desktop of a user having submitted the second write request. According to an illustrative embodiment, the first and the second write request are received from the same user and the reference count remains unchanged. This has the advantage of giving the user flexibility to organize his/her own files in the file system, for example, by storing the same file in different locations without constraints. At the same time the features permit keeping only one copy of the file in the shared storage capacity. According to some illustrative embodiments, in case the first and the second write request are received from different users, the reference count and the file access list is updated accordingly.
[0030] According to some illustrative embodiments, the method further comprises:
receiving an update request from the user, the update request being indicative of one of the first files which is to be modified by the user; storing the modified first file in the shared storage capacity; and creating a pointer to the modified file in the local file system of the user.
According to some illustrative embodiments, the method further comprises deleting the pointer pointing to the stored modified first file.
[0034] According to embodiments, the modification of the file is executed by creating a modified local copy F′ of the first file F to be modified, the local copy being stored to the local file system of the user, and executing a write request as described beforehand for writing the modified local copy F.
[0035] According to one embodiment, the virtual desktop is provided by the virtual desktop environment as an instance of a virtual machine image, and a graphical user interface of the virtual desktop is displayed on a screen of a user-specific processing device to the user of said processing device. Depending on the embodiment, the processing device may be a smartphone, a netbook, a workstation, or the like. In particular, the processing device may be a thin client processing device having only limited hardware resources.
[0036] According to another illustrative embodiment, the user is one of a plurality of users respectively having assigned a user-specific processing device. The virtual desktop is one out of a plurality of virtual desktops. Each of the plurality of virtual desktops is provided to one of the processing devices by the virtual desktop environment. A server hosting the virtual desktop environment is connected to each of the user-specific processing devices via a network. The steps executed by embodiments of the present invention as described above may be executed by a storage infrastructure manager running on the server.
[0037] In a further aspect, the invention relates to a computer-readable non-transitory storage medium comprising computer-readable instructions which, when executed by a processor, cause the processor to perform the method steps of anyone of the above embodiments.
[0038] In another aspect, the invention relates to a computer system for optimizing the storage allocation in a virtual desktop environment, the virtual desktop environment managing a shared storage capacity, wherein the shared storage capacity includes one or more previously stored files, each stored file being associated with a respective unique first file identifier, the virtual desktop environment providing at least one virtual desktop to a processing device of a user. The computer system comprises:
the shared storage capacity; and a server processing device hosting a virtual storage infrastructure manager, wherein the virtual storage infrastructure manager is adapted for:
receiving via the virtual desktop environment a first write request for writing a second file specified in the request; determining a second file identifier of the specified file; comparing the second file identifier with each of the first file identifiers of any first file having been stored to the shared storage capacities; when the second file identifier is identical to one of the first file identifiers, creating a pointer to the stored first file associated with that first file identifier; and when the second file identifier is not identical to anyone of the first file identifiers, storing the specified second file associated with the second file identifier in the shared storage capacity wherein the second file identifier is stored as a further first file identifier and the second file is stored as a further first file, and creating a pointer to the stored further first file.
[0046] According to another illustrative embodiment, the client processing device is connected to the server processing device via a network and is operable to request the virtual desktop from the virtual desktop environment via said network. According to further embodiments, the client device is one of a plurality of client devices respectively assigned to one of a plurality of different users, each of the client devices being operable to request a virtual desktop from the virtual desktop environment via the network.
[0047] According to some illustrative embodiments, the virtual desktops provided to each of the client devices comprises GUI elements which respectively represent the pointers having been created upon a write request of the user of the respective client device. The visible properties of said GUI elements, e.g., color, icon type and the like, are identical to GUI elements used by the respective virtual desktop environment for displaying files, thus giving the user the impression of working with a real file instead of a link.
[0048] As will be appreciated by one skilled in the art, aspects of the present invention may be embodied as a system, method or computer program product. Accordingly, if not explicitly stated otherwise, aspects of the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, micro-code, etc.) or an embodiment combining software and hardware aspects that may all generally be referred to herein as a ‘module’ or ‘system’. Any combination of one or more computer-readable medium(s) may be utilized.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0049] The invention, as well as a preferred mode of use and further objectives and advantages thereof, will best be understood by reference to the following detailed description of illustrative embodiments when read in conjunction with the accompanying drawings, wherein:
[0050] FIG. 1 illustrates system architecture for the execution of a method for optimizing the storage allocation in a virtual desktop environment,
[0051] FIG. 2 is a flowchart of a method for optimizing the storage allocation in a virtual desktop environment, and
[0052] FIG. 3 is a block diagram of a server processing device and a client processing device.
DETAILED DESCRIPTION
[0053] In the following, like numbered elements in the figures either designate similar elements or designate elements that perform an equivalent function. Elements which have been discussed previously will not necessarily be discussed in later figures if the function is equivalent.
[0054] FIG. 1 depicts a system architecture 100 operable to execute a process of optimizing the storage allocation in a virtual desktop environment. The term “virtual desktop environment” as described herein means a system having distributed resources for providing desktop services to end users.
[0055] The system 100 provides thin clients 123 , which are communicatively coupled to a shared storage capacity 113 via a virtual storage infrastructure manager (VSIM) 105 and a computer network 103 such as the internet. The virtual storage infrastructure manager 105 has access to the shared data storage 113 via a space optimizer 109 . The space optimizer 109 may be an integral part of or may be operatively coupled to the virtual storage infrastructure manager running on a remote server 120 . The server 120 can perform any server function and may comprise, for example, data servers, application servers, or web servers.
[0056] The thin client 123 may be, for example, a networked desktop computing device without local storage. It may have a lightweight embedded operating system or firmware and provides user authentication, network/server access, remote display, and support for input/output including keyboard, mouse, local USB, and printing capabilities. The thin client 123 runs a virtual desktop through its connection to the server 120 . The virtual desktop may provide one or more views displayed via a graphical user interface (GUI) 101 of the thin client 123 to a user. The thin client 123 is acting as interface between the user and the shared storage capacity 113 . The thin client 123 is specific to the user, and displays GUI elements representing elements of a local file system to said user. The local file system of the user is adaptable by the user, thus allowing the user to determine the organization of the files owned to the user. The local file system may contain a user-private storage 316 , 317 (cf. FIG. 3 ) wherein file pointers pointing to files accessible by said user may be stored.
[0057] An application programming interface (API) 107 handles requests from the virtual desktop user and returns responses to those requests. The requests may be, for example, CRUD (create, read, update, delete) operations. These requests are forwarded to the space optimizer 109 . The space optimizer 109 enables and manages the requests, such as the CRUD operations, and translates user requests into requests to the shared storage capacity 113 to retrieve and store information. The API interface 107 is under control of the VSIM and isolates the virtual desktops 310 depicted in FIG. 3 from directly interacting with the shared storage capacity 113 .
[0058] The shared storage capacity 113 is operatively coupled to the server 120 . For example, the shared storage capacity may be part of the server or accessible by the server via a network. The shared storage capacity 113 may consist of one or more interconnected storage devices, such as a RAID, for storing data files. The system 100 provides information on the stored files 117 . The information comprises, for example, an access control list, a file identifier, a reference count number describing the number of users having access to a file, etc. This information is stored in a metadata repository 111 . The metadata repository 111 is operatively coupled to the space optimizer 109 for exchanging that information.
[0059] FIG. 2 is a flowchart of a method for optimizing the storage allocation in a virtual desktop environment. In step 201 , the API 107 of the VSIM 105 receives requests to write a specific file in the shared storage capacity 113 . The request being triggered, for example, by a user saving a specific file attached to his/her email in one user-private storage. The user-private storage comprises a local file system of a virtual desktop. The virtual desktop is provided to the thin client 123 . The API forwards the request to the space optimizer 109 . The space optimizer 109 in step 203 calculates a second identifier for the specified file. The second identifier may include, for example and without limitation, a file Cyclic Redundancy Check number, Hash number, SHA-1 or MD5. In step 205 , the space optimizer 109 compares the second identifier of the specified file being requested with the first identifiers of the files previously stored in the shared storage capacity 113 . The space optimizer 109 retrieves the identifiers of the stored files from the metadata repository 111 .
[0060] In case the second identifier is identical to one of the first file identifiers, the space optimizer first adds the user CD to an access control list and/or increments a reference count associated with the stored file having the first identifier identical to the second identifier. The access control list and the reference count are then stored in the metadata repository 111 . Next, the space optimizer 109 creates a pointer to the existing stored file associated with that first identifier. In step 209 , the pointer is created in the user-private storage comprising the local file system of the virtual desktop requested by the user. The user-private storage may be a logical volume or a physical storage volume. When the specified file is requested a second time, by the same user, for writing said file in a second location within the same directory tree of the file system of the virtual desktop, a second pointer is created which points to the existing first file in the user-private storage of the user. In this case the reference count remains unchanged.
[0061] In case the second write request was received from a second user, the other user requesting to write a file having already been stored by the first user, a pointer pointing to the existing file in the shared storage capacity 113 is created in the local file directory of a user-private storage of said second user. For example, the second user may use a second thin client. The second thin client operates a second virtual desktop displaying graphical references of elements of a local file directory tree defined by said second user. In this case, the reference count is updated.
[0062] In case the second file identifier is not identical to anyone of the first file identifiers, the space optimizer 109 will first create an access control list and/or a reference count for the specified file, and adds the user ID to the access control list and/or increments the reference count. The access control list and the reference count are then stored in the metadata repository 111 . Next, in step 207 , the space optimizer 109 stores the specified file associated with the second file identifier in the shared storage capacity 113 and create a new pointer to the specified file in the user-private storage comprising the local file system of the virtual desktop chosen by the user. The second identifier is then stored as a further first identifier.
[0063] There is another use case where the user is requesting a deletion of one of the previously stored files in the shared storage capacity. In this case, the user ID of that user is removed from the access control list of that file, and the reference count of that file is decremented.
[0064] FIG. 3 depicts a virtual desktop environment comprising a server processing device 120 being connected to a client processing device, e.g., a thin client 123 . 1 via a network 103 , e.g., the Internet or an intranet. The thin client 123 . 1 comprises a processor 304 and a working memory 303 . The working memory 303 comprises user data and program instructions of a virtual desktop 310 having been provided via the network 103 by the virtual storage infrastructure manager 105 being operated by the server 120 . The virtual desktop 310 is an instance of a virtual machine image 301 and may provide a graphical user interface 302 which is displayed to the user 320 of the thin client 123 . 1 on a screen of the thin client 123 . 1 .
[0065] The graphical user interface displayed to the user 320 may comprise graphical user interface elements (GUI elements) representing file pointers stored in storage medium 311 . The storage medium 311 is operatively coupled to the server 120 and may comprise a shared storage capacity 113 and one or more user-private storages (UPS) 316 , 317 . The shared storage capacity 113 may comprise one or more files 313 , 308 , 321 . Each of the files may have assigned an identifier of one or more users being allowed to access that file. The data content of any of the user-private storages comprises data, in particular the file pointers, which are accessible only by one particular user to whom said user-private storage is assigned. For example, UPS 316 may be assigned to user 320 .
[0066] User 320 may create and modify a directory tree and may request to write a file into a particular location of said file tree, whereby the path to that location was specified by the user 320 via the GUI 302 . The GUI 302 may present to the user a graphical representation of the elements of the directory tree and, in particular, of the file pointers 314 pointing to and representing files stored to the shared storage capacity 113 . For example, an icon displayed to the user 320 via the GUIs 302 may represent the file pointer 314 . Said icon may not be discernible from an icon of a real file. Thus, user 320 has the impression of accessing a real file 313 stored to his or her local file directory tree although actually said user 320 accesses only a file pointer 316 stored to his/her user-private storage 316 , whereby said pointer points to file 313 on the shared storage capacity 113 .
[0067] The user-private storage 317 may be assigned to a different user. UPS 317 may also comprise a pointer 315 pointing to file 313 . The file 313 may have assigned an access list comprising the user-IDs of the users assigned to the UPS 316 and UPS 317 .
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Mechanisms for optimizing the storage allocation in a virtual desktop environment (VDE) managing a shared storage capacity, are provided. The shared storage capacity includes previously stored files, each being associated with a respective unique first file identifier, the VDE providing a virtual desktop to a processing device of a user. Upon reception of a first write request for writing a second file specified in the request, a second file identifier of the specified second file is determined and compared with the first file identifier of any first file stored to the shared storage capacity. A pointer to the stored first file associated with that first file identifier is created if the second file identifier is identical to one of the first file identifiers and, if not, the specified second file associated with the second file identifier is stored in the shared storage capacity.
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RELATED APPLICATIONS
This application contains subject matter related to U.S. patent application Ser. No. 008,228 filed on even date herewith and entitled Vertical Magazine Method for Integrated Circuit Device Dispensing, Receiving, Storing, Testing or Binning, by the same inventor.
BACKGROUND OF THE INVENTION
The invention relates to apparatus for optionally dispensing, receiving or storing semiconductor devices including integrated circuits and, more specifically, to apparatus employing vertical stacking of such devices in magazines.
As the semiconductor industry advances in the fabrication and processing of packaged semiconductor devices (sometimes referred to herein for convenience as "devices"), such as thin small outline packages, or TSOPs, testing and sorting of such devices pose challenges in terms of device throughput, test equipment space utilization, and device distribution responsive to test result-responsive sorting.
Currently, processing of thin package devices such as TSOPs is primarily carried out based upon specialized JEDEC (Joint Electronic Device Engineering Council)--specification trays, which are approximately five inches wide by twelve inches long. The JEDEC tray design dictates that the semiconductor devices are carried in a single layer, arranged in mutually perpendicular rows and columns. Tray density, or the number of devices carried by each tray, obviously decreases as device size increases. For reference purposes, if a given device is 0.400 inch wide by 0.750 inch long, a JEDEC tray part capacity, with a nine row by thirteen column configuration, is about 117 parts per tray.
Testing of the devices is conventionally carried out in batches of thirty-two parts (devices) run through a test cycle simultaneously. The devices are then sorted into a number of categories based upon test results and then "binned" into the aforementioned JEDEC trays by a conventional "pick-and-place" robotic arm system. At the present time, as many as sixteen sort categories are employed, and it is anticipated that the number of sort categories will increase as the sophistication and miniaturization of semiconductor devices continue in the future. If each JEDEC tray employed for receiving post-test devices is intended to receive a single bin or sort category, a substantial amount of manufacturing floor space is required to accommodate an arrangement where sixteen JEDEC trays are placed in a horizontal array. Further, the size and complexity of the pick-and-place device required to place tested devices in the trays of such an array become unreasonable. Alternatively, if (for example) sixteen JEDEC trays are stacked in a holding tower in a vertical format, wherein the trays themselves are again horizontally oriented but mutually vertically superimposed, a tray retrieval and presentation mechanism is required. Further, the time to retrieve each tray from the tower, present it for pick-and-placement of a tested device, and replace the tray in the tower severely limits device throughput. As the number of sort categories increases, each of the foregoing approaches to device binning becomes ever-more unwieldy to execute.
Thus, the prior art approach to semiconductor device sorting and binning has demonstrated severe deficiencies in terms of throughput, space utilization, and complexity of required device handling equipment.
BRIEF SUMMARY OF THE INVENTION
The present invention affords a simple, elegant and economical solution to the previously-identified problems with device sorting and binning. By employing a vertical binning approach instead of the prior art horizontal binning approach, embodiments of the present invention offer the ability to simulate the horizontal spatial configuration or "footprint" of a JEDEC tray for convenience of use with conventional, unmodified robotic pick and place equipment. Additional embodiments of the invention enable the binning of tested and sorted devices into an extremely high number of categories in a rapid, accurate manner and subsequent storage, transport and dispensing of the binned devices for subsequent operations.
One embodiment of the invention includes at least one elongated magazine configured for containing a plurality of semiconductor devices, including by way of example thin package devices, in a stacked configuration. The magazine is mounted substantially vertically and removably associated with an indexing element of an elevation assembly, the indexing element being movable to regulate the internal longitudinal volume of the interior of the magazine, in order to receive or present a device at a desired level proximate the top of the magazine from a stack of devices within the magazine. The indexing element may be driven by a stepper motor or other incrementally or continuously controllable drive employed in the elevation assembly to ensure presentation or receipt of the top device in the magazine at a correct, controllable vertical height for easy access by a pick and place system. The magazine and elevation assembly together may be said to comprise a magazine unit.
It is currently contemplated that a best mode of implementation of the invention may involve a plurality of magazine units in modular form placed in an array, each including a removable, vertically extending magazine placed in close mutual horizontal proximity and, if desired, in a pattern to simulate at least some of the rows and columns exhibited by the aforementioned JEDEC trays. Thus, each magazine is associated with an indexing element responsive to a separately-controllable drive of a discrete elevation assembly for raising or lowering a stack of devices within that magazine to either present an uppermost device in a magazine stack for retrieval, or to lower an uppermost device in a stack to provide a location for placement of another device in that magazine.
Embodiments of the invention also include a method of binning devices and a method of dispensing stored devices for further handling.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
FIG. 1 is a perspective view of a single magazine module embodiment of the invention;
FIG. 1A is a top elevation of the magazine depicted in FIG. 1;
FIG. 1B is a side sectional elevation of a mid-portion of the magazine depicted in FIG. 1;
FIG. 2 is a perspective view of a multiple-magazine module embodiment of the invention;
FIG. 3 is a top view of a single magazine embodiment configured for containment of multiple vertical stacks of devices;
FIG. 4 is a schematic depicting dispensing, testing, and binning of devices according to the present invention;
FIG. 5 is a schematic of a square, four magazine module by four magazine module array of one embodiment of the invention;
FIG. 6 is a linear, eight magazine module array of one embodiment of the invention;
FIG. 7 is a schematic top elevation of two module arrays alternately movable into a target field of a pick-and-place mechanism;
FIG. 8 is a schematic top elevation of an elongated two module-deep linear array translatable across the target field of a pick-and-place mechanism; and
FIG. 9 is a schematic top elevation of a circular, carousel-type array rotatable into the target field of a pick-and-place mechanism.
DETAILED DESCRIPTION OF THE INVENTION
Referring to FIG. 1, magazine unit 10 comprises an elongated, generally tubular magazine 12 defining an interior cavity 14 the cross section of which may be varied in size and shape responsive to that of the devices 100 (such as the aforementioned TSOPs) to be contained therein. Magazine 12 may be formed of any suitable metallic or non-metallic material, although it is contemplated that it be molded from an anti-electrostatic discharge (ESD) polymer, or coated with such a material. As shown, magazine cavity 14 is sized to accommodate a plurality of devices 100 stacked in vertically superimposed relationship. Also as shown, one or more walls of magazine 12 may include an elongated view port 16, so that the filled versus empty status of the magazine may be visually verified as desired. It is also desirable that magazine 12 include a floor 18 movable within interior cavity 14. As shown in FIG. 1A, floor 18 is preferably larger than aperture 14a at the bottom of interior cavity 14, so that devices 100 in magazine 12 will be retained from below by floor 18 when magazine 12 is being handled. As shown in FIG. 1B, floor 18 may include skirts or other peripheral extensions 18a to prevent tilting, cocking and jamming of floor 18 as it moves up and down within magazine cavity 14.
Magazine 12 is placed above an elevation assembly 20 at a fixed vertical level L, and may be stabbed into a fixture, depicted in FIG. 1 as receptacle 22 (shown in broken lines), to provide proper horizontal, vertical and angular (about a vertical axes) orientation for magazine 12. It is preferred, although not required, that magazine 12 be secured against vertical movement by a detent assembly comprised of one or more resiliently-biased detent elements 24 cooperating with a like number of recesses 26 in a sidewall of magazine 12. The detent assembly may comprise a leaf-spring biased detent element as shown, or biasing may be provided by a coil spring, a resilient elastomer, or otherwise as known in the art, or may comprise a resilient wall portion molded into receptacle 22. Alternatively, magazine 12 may be frictionally retained within receptacle 22, or may be positively locked within receptacle 22 by a latch or pin-type locking arrangement, such mechanisms being conventional.
An elongated, rod-like indexing element 30 is extendable upwardly into interior cavity 14 of magazine 12 under the power and control of drive 32, which may comprise a stepper motor, a screw drive, or other suitable incrementally or continuously controllable drive mechanism as known in the art. As shown, indexing element 30 extends vertically through drive 32 and upwardly into magazine 12, where it contacts the bottom of floor 18. As shown in FIGS. 1A and 1B, element 30 may be received within a cup 34 formed in the bottom of floor 18. Cup 34, like skirts 18a, may alleviate any tendency of floor 18 to tilt, cock or jam. If desired, the upper end of indexing element 30 may be of rectangular or other suitable cross section, and the interior blind bore of cup 34 configured to mate therewith. Drive 32 may be controlled responsive to removal or addition of a device to its associated magazine 12 by a pick-and-place mechanism to, respectively, extend or retract indexing element 30 by an increment equivalent to the depth (thickness) of a given device 100. Such movement may be software-controlled for ease of accommodating different devices 100.
Optionally and desirably, each magazine 12 may carry identifying indicia or an identification device thereon to facilitate proper identification and use of a given magazine and its contents. For example, as shown in FIG. 1, magazine 12 may bear an identification device 40 such as a bar code or magnetic strip (such as is employed with credit cards) on an exterior sidewall thereof. Alternatively, and again as shown in FIG. 1, magazine 12 may bear a more sophisticated electronic identification device 42 utilizing a memory device such as an EEPROM or flash memory. An RFID (Radio Frequency Identification) device may also be employed for enhanced remote inventory and theft control through electronic tracking or monitoring. Such bar code 40 or identification devices 42 may be employed to retain and provide "bin" information as to the test characteristics exhibited by the binned devices carried by the magazine, part count, manufacturing origin, test date, test equipment, test protocol, and other useful information, such as the location of a specific part in a stack of parts deposited in a given magazine 12.
As depicted in FIG. 2, a plurality of magazine units 10, optionally in identical modular form (hereinafter "magazine modules"), may be arranged in a close horizontally-adjacent array 110 to dispense or receive devices 100 in association with a pick-and-place mechanism. This arrangement is particularly beneficial for receiving tested and sorted devices 100, with each magazine 12 of the array 110 comprising a "bin" to receive devices exhibiting particular characteristics under test and sorted accordingly. As shown in broken lines 60, the magazine module array 110 may be arranged to simulate the device containment pattern size and shape of the aforementioned JEDEC trays, while eliminating the previously-described conventional practice of presenting different trays for receiving differently binned devices. Moreover, using the invention, a pick-and-place mechanism may thus be programmed to dispense tested, sorted chips to only one specific X-Y plane (transverse to the axes of magazines 12) location for each sort category, or bin, of tested devices.
As desired, the magazine units or modules 10 may be arranged to comprise a square array (for example, four modules 10 by four modules as shown in FIG. 5), another rectangular array (for example, four modules 10 by two modules 10 as shown in FIG. 2), a linear array (for example, a line of eight modules as shown in FIG. 6), or in any other desired arrangement. Further, and again as desired, two or more module arrays 110 may be employed if a large number of bins are required and the pick-and-place device 120 has a limited horizontal travel, the multiple arrays 110 being alternatively placeable within reach of a target field 124 of the pick-and-place arm 122, as shown in FIG. 7. Also, a longitudinally extended module array 110 may be mounted so as to be linearly translatable through a target field 124 of a pick and place arm 122, as shown in FIG. 8. Finally, and as illustrated in FIG. 9, a circular carousel-type array 110 may be employed to rapidly, rotationally present each magazine module 10 at the same, specific, fixed target field 124 for pick-and-place.
As shown in both FIGS. 1 and 2, the magazine modules 10 may be easily bolted or otherwise secured by fasteners to a module or array support plate in any desired pattern and spacing using apertures 72 in flange plates 70 at the tops of drives 32. Alternatively, the magazine modules 10 may be frictionally seated in recesses in a support, spring-loaded or positively-locked clamps may be employed to retain magazine modules 10, resiliently-biased detent devices employed, or any other suitable retention structure known in the art. Further, drives 32 may be linked to a test apparatus and sorting device by quick-release electrical connections (such as male-female connectors, resiliently-biased surface contacts, or other suitable connections known in the art).
When a given magazine 12 is completely filled, such status being conveyed to the operator by, for example, a sensor 50 (see FIG. 1) sensing the position of indexing element 30 or a proximity sensor 52 (see FIG. 1) located on the interior of receptacle 22 sensing the proximity of floor 18 to the bottom of that magazine 12, the full magazine 12 is removed and replaced by an empty one. Triggering of such sensors 50, 52 may result in an alarm or other indicator to alert the operator, and a signal to a control system to stop the binning process until the full magazine is replaced. Position sensor 50 may sense actual travel of indexing element 30, or may merely react to proximity of an indicator located on the shaft of indexing element 30. Proximity sensor 52 may comprise a contact switch, a photocell, a reflection type optical encoder, an ultrasound sensor, or other suitable sensor known in the art. In lieu of being associated with receptacle 22, sensor 52 may be built into the lower end of each magazine 12, and electrical contact for providing power and passing a signal from the sensor made with a host device such as a programmed computer associated (for example) with a testing device or a sorting device when magazine 12 is plugged into receptacle 22. Male/female mating contacts, resiliently-biased surface contacts, or other conventional arrangement may be employed to make the connection.
Position sensor 50 might also be employed to indicate when a dispensing magazine 12 has been emptied (i.e, indexing element 30 is at full extension), and a proximity sensor 52a might be employed at the top of each dispensing magazine 12 to signal the proximity of floor 18 to the mouth 14b of interior magazine cavity 14, sensor 52a having a quick-disconnect electrical connection 54 associated therewith for connecting sensor 52a to an alarm or other indicator, to the control for the mechanism being fed by the magazine, and to the control for elevator drive 32. Alternatively, the connection for sensor 52a may be located at the bottom of magazine 12 so that entry of the bottom of magazine 12 into a receptacle 22 also effects an electrical connection for the sensor. Further, the sensor may extend longitudinally along the vertical length of the magazine as shown at 52b, to sense the proximity of the floor 18 in a continuous manner, and thus the magnitude of the interior cavity 14 of the magazine 12 above floor 18 on a continuous basis. In a very simple form, the "sensor" may comprise a graduated indicator scale 52c inscribed on the exterior of magazine 12 next to view port 16 in gradations equal to the thickness of the devices contained therein and numbered to visually indicate the number of devices in the magazine, the remaining magazine capacity, or both. Alternatively, the scale 52c may be printed on an adhesive-backed strip or film to be removably adhered to a magazine 12 so that different scales may be used for devices of different thicknesses.
As shown in FIG. 3, the magazine of the present invention may be configured in an embodiment 210 to present or receive a plurality, for example four (4), of devices 100 by employing four interior cavities 14 arranged about a central passage 212 for receiving an indexing element 30, the floors 18 within the four cavities 14 being linked to a central support 214 which is engaged by indexing element 30.
FIG. 4 schematically depicts the dispensing of devices 100 from an array 110a of magazine units 10 according to the present invention, retrieval with arm 122a of a pick-and-place mechanism 120a and placement into a test board preparatory to passage through test apparatus 130 for electrical testing (optionally at elevated temperature) and sorting of devices 100 as known in the art, retrieval of tested devices 100 with arm 122b of a second pick-and-place mechanism 120b and binning of same into additional magazine units 10 in an array 110b in accordance with their exhibited test characteristics. Other types of device handling mechanisms may also be employed, and it is specifically contemplated that a translatable chute-type gravity feed mechanism is suitable for dispensing tested devices 100 into various magazines 10 in accordance with their test characteristics. Many types of such electrical tests being known and conventionally practiced in the art, and the type of such tests being unrelated to the present invention and its practice, no further description thereof will be made herein.
The present invention has been disclosed as having specific utility with TSOP devices. However, it is contemplated as having utility with any type of semiconductor device, particularly packaged devices such as (for example) small outline j-lead (SOJ) devices, thin quad flat pack (TQFP) devices, dual-in-line package (DIP) devices, ball grid array (BGA) devices, and chip scale package (CSP) devices.
While the present invention has been described in terms of certain illustrated embodiments, those of ordinary skill in the art will readily recognize that it is not so limited. Many additions, deletions and modifications may be made to the embodiments disclosed, as well as combinations of features from different disclosed embodiments, without departing from the scope of the invention as hereinafter claimed.
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An apparatus for dispensing, receiving or storing packaged integrated circuit devices using at least one vertically-oriented, removable, tubular magazine disposed above a controllably-driven, rod-like indexing element extending from a drive below the magazine. A magazine, with an associated indexing element and drive, is configurable as an individual magazine module. The indexing element, under power of the drive, raises or lowers a vertical stack of devices to a desired level adjacent the top of the magazine to dispense or receive an individual device from a feed mechanism, such as a pick-and-place mechanism. A number of magazine modules may be assembled in a multi-module array, which is particularly suitable for binning tested devices, with a sort category being directed to each magazine.
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CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to the German application No. 10 2005 015 419.0, filed Apr. 4, 2005 which is incorporated by reference herein in its entirety.
FIELD OF INVENTION
[0002] The invention relates to an arrangement comprising a look-up table of an LCD display module, to which video input values can be fed, the look -up table assigning video output values to the video input values and feeding these video output values to an LCD display of the LCD display module.
BACKGROUND OF INVENTION
[0003] In the medical field, in particular, the requirements for an image reproduction system are extremely high in terms of the image reproduction characteristics of this system, e.g. of a panel of a flat screen. The image reproduction characteristics indicate how an electrical image signal is converted into an optical signal, consisting of luminance and chrominance. It is, for example, required that luminance increase equidistantly in perception terms as a function of a video input signal (a video level). Equidistantly in perception terms means that the human eye perceives the image e.g. at a video level of 50% of its maximum value to be half as bright as the image with a video level of 100%. In order to achieve this, measures are required in order to adapt the course of luminance characteristics to the sensitivity of the human eye.
SUMMARY OF INVENTION
[0004] The luminance characteristics can be adapted with the aid of a look-up table, as it is called. The correction is made in that a graphics processor suitable for controlling a panel of a flat screen inputs firstly video input values and video output values assigned to these video input values in a look-up table. Which video output value is then given to the panel depends on the video input value, by which means a luminance can be adjusted in accordance with desired luminance characteristics. In other words, the correction occurs in the manner in which the digitalized image is evaluated by means of the look-up table; instead of a video input value, a video output value assigned to this video input value is written to the panel.
[0005] In this way, it is possible to adapt the image reproduction characteristics via the look-up table such that e.g. these characteristics conform to the DICOM standard. According to this standard, the luminance range from 0.05 cd/m 2 to 4,000 cd/m 2 is subdivided into 1,024 steps Oust noticeable differences) so that the luminance difference between the individual steps is just perceptible to the eye. By this means, the luminance increases evenly in perception terms.
[0006] In order to calibrate the luminance characteristics e.g. in accordance with this DICOM standard, a large number of test images are required which each represent a test pattern. For example, approx. 33 grey levels have to be calibrated for the foreground and approximately 50 grey levels for the background, a suitable measurement head recording the luminances during this calibration. A suitable calibration program that is capable of running on a personal computer calculates video output values from the video input values, the recorded luminances and the target luminances according to DICOM and stores these in the look-up table.
[0007] Due to the large number of test images which are generated by a suitable graphics card of a computer, adequate memory capacity is necessary, as a result of which not all the test images required can be stored in an FPGA module or in a display store of the LCD display module.
[0008] An object of the present invention is to create an arrangement for testing an LCD display by means of which a large number of test patterns can be generated for calibration procedures or for checking the image quality. At the same time, the use of a graphics card should be dispensed with.
[0009] This object is achieved by the claims.
[0010] The invention proceeds from the idea that only a coded test image is needed in order to generate a large number of individual test patterns, i.e. a large number of individual decoded test images that can be represented on a panel, whereby these test patterns can be decoded by a look-up table regularly available in LCD display modules. A look-up table usually has 256 correction points, through which e.g. 256 graphics elements are addressable. In the event that this look-up table has an 8-bit resolution, each element can be displayed in 256 grey levels and/or in the case of a color display module in 2 24 colors.
[0011] In an embodiment of the invention according to the measures specified in claim 2 , it is provided that a computer, a PDA or a mobile telephone generates at least one control instruction in accordance with a user input or automatically. This simplifies field calibration, whereby a service engineer is able to call up special test patterns or to activate a calibration program which calls up in succession different test patterns required for calibration. Particularly where a mobile telephone or a PDA is used, the communication interface can be fashioned as a Bluetooth interface.
[0012] Further advantageous embodiments of the invention will emerge from the dependent claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] With the aid of the drawings in which an exemplary embodiment of the invention is illustrated, the invention and embodiments and advantages thereof are explained in detail below.
[0014] FIG. 1 shows an arrangement for controlling an LCD display and
[0015] FIGS. 2 to 4 show various test patterns which can be displayed on an LCD display.
DETAILED DESCRIPTION OF INVENTION
[0016] In FIG. 1 , a look-up table to which the video input steps of a controller 2 can be fed is labeled 1 . The controller 2 can be an integral part of a graphics processor, to which during normal operating mode image signals are transmitted. The graphics processor processes the image signals, said graphics processor transmitting the processed signals in the form of video input steps to the look-up table 1 . the look-up table 1 evaluates the video input steps for optimizing the image reproduction characteristics and applies video output steps assigned to the video input steps to an LCD display 3 .
[0017] In order to generate a plethora of test patterns (decoded test images) from a coded test image for calibration procedures during a calibration phase, there is provided in the present exemplary embodiment a memory 4 in which the test image can be stored. The memory 4 and the controller 2 as well as the look-up table 1 and the LCD display 3 are integral components of an LCD display module. The test image is input in the memory 4 e.g. by a computer not shown here, e.g. a computer in the form of a personal computer, a PDA (Personal Digital Assistant) or a mobile telephone, via a suitable communication interface 5 . The transfer of the test image is displayed to the controller 2 by a control instruction transmitted via the communication interface 5 . It is, of course, possible to transfer the test image firstly to the controller 2 which writes the test image into the memory 4 . It is also possible to store the coded test image, for example, in an EEPROM of the arrangement, as a result of which transfer of the test image to the arrangement is dispensed with and the calibration procedure shortened. Furthermore, it is conceivable to store not the complete test image but only such data as is required in order to generate the test image. In this case, the memory requirement in the arrangement is reduced, in that in order to generate the test image of the arrangement only an instruction for generating the test image via the communication interface 5 is transmitted, and a suitable program in the controller 2 generates the test image.
[0018] A user selects, directed by a menus, via a selection program which is capable of running on the personal computer a test pattern, by means of which the selection program generates a further control instruction and transmits it to the controller 2 via the communication interface 5 . Depending on this control instruction, the controller 2 loads the look-up table 1 with video output values with which a test pattern of the test image—as will be shown below—is decoded. The test patterns can also be selected automatically, whereby in this case calibration software selects and displays on the LCD display 3 different test patterns e.g. in succession. The luminances of the test patterns can e.g. be recorded and analyzed in order to optimize the image reproduction characteristics.
[0019] Reference is made below to FIGS. 2 to 4 in which different test patterns which can be displayed on an LCD display are shown.
[0020] It is assumed that a coded test image stored in a display store BS can be displayed on a monochrome LCD display with a resolution of 1024×1024 pixels. It is also assumed, for the sake of simplicity, that an 8-bit look-up table LUT is provided for evaluating the video input steps, as a result of which 256 graphics elements, e.g. elements in the form of a square, a triangle or a circle, can be arranged in the test image and displayed in any grey level or color. For the sake of simplicity, in the present example only a coded monochrome test image is stored in the display store BS. In the event that an element is to be displayed in color, for each video input value a video output value has to be provided for each R, G and B elementary color.
[0021] In FIG. 2 , video output values VA are assigned to video input values VE in a look-up table LUT loaded by the controller 2 . The video output value 255 is assigned to the video input value 4 , while the video output value 0 is assigned to each of the remaining video input values. This means that the memory content of the display store BS coded with the value 4 is displayed white on an LCD display LA (pixel range from 341 to 682 ). By contrast, the memory content of the display store BS which is not coded with the value 4 is displayed black on the LCD display LA (remaining range), which is shown in the Figures by vertical lines.
[0022] In the example according to FIG. 3 , the video input value 4 is again stored in the memory cells which correspond to pixels 341 to 682 of the LCD display LA (same coded test image). According to the population of the look-up table LUT, the video output value 128 is assigned to this video input value, as a result of which a test pattern in the form of a grey square (shown hatched) is displayed in the range of pixels from 341 to 682 and the remaining pixel range of the LCD display LA is displayed black.
[0023] Based on the allocation of the display store BS and of the look-up table LUT according to FIG. 4 , in which the video output value 255 is assigned to the video input value 9 and the video output value 0 to the remaining video input values, a white triangle is decoded as a test pattern in the test image in a pixel range from 682 to 1023 and displayed on the LCD display LA, the remaining pixel range of the LCD display LA again being shown black.
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An arrangement comprising a look-up table of an LCD display module is proposed, to which look-up table video input values can be fed, the look-up table assigning video output values to the video input values and feeding the video output values to an LCD display of the LCD display module. Through appropriate measures, a large number of test patterns for calibration procedures can be processed and displayed on the LCD display.
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BACKGROUND OF THE INVENTION
This invention relates generally to a processor, or high temperature vacuum furnace, preferably for heating dental reconstruction products using sintered powder metal at very high temperatures, and relates more particularly to a special muffle chamber for heating dental reconstruction products in a vacuum environment.
The type of muffle chamber described above includes an elongated muffle tube in which the product to be fired is placed. The interior of the muffle tube defines the vacuum chamber and is first evacuated of atmospheric air so that a high degree of vacuum is achieved. Then the tube is rapidly heated preferably by electrical heating elements until an interior temperature of about 1200° C. (2192° F.) by radiant thermal energy is achieved. The energy passes from the heating elements first to the cylindric wall of the muffle tube and thereupon from the heated tube wall to the product to be fired at the general center of the vacuum chamber formed by the tube.
The primary problem encountered on muffle tubes now in use is that the length of the tube is determined in accordance with thermal shock resistance characteristics of the tubes, its thermal conductivity, and in accordance with the maximum use temperature of silicone rubber seals at the longitudinal ends of the tube that are necessary to maintain the vacuum in the tubes.
Many ceramic materials are unable to withstand sudden changes in temperature without flaking, dunting, spalling, cracking, or other form of disintegration. The extent to which a material can withstand different temperatures along its length without such disintegration or cracking can be referred to as thermal shock resistance, which is often defined in terms of the maximum temperature interval through which the material can be rapidly chilled without fracturing or otherwise disintegrating. A discussion on this subject can be found in The Chemistry and Physics of Clays and Other Ceramic Materials by R. W. Grimshaw, Fourth Edition, Wiley-Interscience, New York, 1971, pages 949-955; and in Glass Ceramics by P. W. McMillan, Academic Press, New York, 1964, pages 191-193. The thermal shock resistance characteristic is such that a maximum thermal differential, or gradient, per unit length of the tube cannot be exceeded without disintegration of the tube. Because the maximum use temperature of the silicone rubber seals is about 200° C. (392° F.), the longitudinal ends of the tube must be kept below that temperature, and preferably below 150° C. (302° F.). Thus, sufficient length of tube is required to allow cooling from a heating chamber temperature of 1200° C. at its longitudinal center to 150° C. at its ends without exceeding the maximum thermal shock resistance. Therefore, if no insulation were utilized to control the cooling of the tube along its length, and only distance from the heating element allowed cooling, a thermal gradient, possibly only 30° C. (86°) per inch would be achieved. Accordingly, a tube length of about 6 feet, that is, with the ends at about 35 inches from the longitudinal center, would be the necessary result. The cumbersome aspects of such a dimension are apparent, and even more so when the mechanisms associated with the tube, such as electric heating elements, the vacuum apparatus, the outer blowers, and so on, are taken into consideration.
The invention allows for a shortened muffle tube to a more manageable length. The invention includes placing insulation around a shortened tube made of a ceramic material which has a relatively low thermal shock resistance characteristic compared to other materials, such as metals, and the like, but the novel structure of the furnace, maximizes the thermal gradient to come close to the maximum thermal shock resistance of the tube material. Accordingly, the shortest tube length is achieved. Insulation wrapped around the tube placed above and below the center area of the longitudinal dimension of the tube, that is, above and below the heating elements, have resulted in the cracking of the walls of the tube at the point where the insulation began at the walls of the tube in the plane perpendicular to the center axis of the tube upon heating of the tube. This result can be attributed to a too sudden reduction of temperature at the point of juncture between the hot heating chamber and the plane at the insulation wrapping.
SUMMARY OF THE INVENTION
It is therefore an object of the invention to control and uniformize the heating of a relatively short vacuum tube within a furnace for dental reconstruction products using sintered powder metal that is relatively short in length.
It is a further object of the invention to provide a relatively short ceramic vacuum tube which forms a part of a furnace for dental reconstruction products that is subjected to cooling close to its thermal shock resistance, and one that avoids both cracking of the tube and exceeding the maximum use temperature of the vacuum seals at the ends of the tube during the heating mode, at the shortest optimum length.
In accordance with these and other objects of the invention which will become apparent hereinafter, there is provided a vacuum furnace for heating dental reconstruction products using sintered powder metal that includes a sealed cylindrical vacuum tube having a heating chamber, opposed ends, and a length extending between the opposed ends. The tube is made of a ceramic material, which material has a generally low thermal thermal conductivity and therefore a relatively low shock resistance characteristic. Seals having a low maximum use temperature are positioned at the opposed ends, and insulation is positioned around and connected to the vacuum tube proximate the opposed ends.
In addition, stepped clearances formed between the insulation and the tube maximize a controlled uniform cooling of the tube to obtain the shortest possible tube length. The insulation and the clearances are capable of controlling the heat being radiated by the heating elements during the heating process by blocking off a portion or all the lines of radiant energy emanating from the heating elements in the area of the tube at the clearances so that the tube absorbs heat at a gradual temperature gradient along the length of the tube that is less than the thermal gradient of heat differential that would be beyond the tolerance of the thermal shock resistance characteristic of the tube. Thus, cracking of the muffle tube during heating is avoided.
As noted earlier, the maximum use temperature of the seals is approximately 200° C., and it is preferable to keep the ends of the tube no greater than 150° C. A preferred material of the tube is mullite (3Al 2 O 3 ·Si 2 ); other materials, however, may be used. The present invention encompasses the utilization of stepped-back insulation designed and configured to maximize and come close to the maximum thermal gradient of the tube, such that a tube of other refractory materials may be constructed to similarly attain the shortest possible length vacuum tube.
The tube has inner and outer surfaces, an axis, and a longitudinal center measured along the longitudinal dimension. The tube includes a heating chamber portion centered at the longitudinal center, and further has first and second tube portions extending between the heating chamber portion and each of the opposed ends; and the insulation is a generally cylindrical insulation block placed around the outer surface and connected to the tube proximate to the opposed ends at first and second connecting areas. The insulation block includes a center block portion aligned with the heating chamber portion and a plurality of block portions generally aligned with the first and second tube portions, respectively, to the first and second connecting areas, respectively.
The stepped clearances include a central clearance formed between the center block portion and the outer surface of the tube, and a plurality of additional clearances formed between the first and second block portions and the outer surface of the tube. The central clearance is aligned with the heating chamber of the muffle tube and is spaced from the outer surface at a first distance and the plurality of additional clearances are spaced from the outer surface at gradually decreasing distances from the first distance to the connecting areas.
The present invention will be better understood, and the objects and important features, other than those specifically enumerated above, will become apparent when consideration is given to the following details and description, which, when taken in conjunction with the annexed drawings, describes and illustrates a preferred embodiment as well as modifications of the invention. Other embodiments or modifications may be suggested to those having the benefit of the teachings herein, and such other embodiments or modifications are intended to be reserved especially as they fall within the scope of the claims following the end of this specification.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side sectional view of the muffle tube; and
FIG. 2 is partial section view of a prototype model utilized in tests.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Reference is now made to the drawings in which identical or similar parts are designated by the same reference numerals throughout.
FIG. 1 is a sectional view of a processor, or vacuum furnace, 10 for heating dental reconstruction products. Furnace 10 includes a generally vertical muffle tube 12 that includes a cylindrical wall 13 forming a cylindrical chamber 14 and having outer and inner surfaces 16 and 18, respectively. Tube 12 as best shown therein is about 20 inches in length and about 31/2 inches to 4 inches in diameter; it is to be understood that the length of tube 12 may vary, but such lengths are short relative to the long muffle tubes presently used by the trade and industry. A generally cylindrical upper insulation block 20 having a bottom planar surface 21 is positioned in the upper portion of chamber 14. Block 20 is suitably hung by a number of brackets 22 from a top cover plate 23 that extends across the open top end of tube 12. An upper annular space, or clearance, 24 is formed between inner surface 18 and cylindrical insulation block 20. Also, a generally annular upper space, or clearance, 26 is formed in chamber 14 between top cover plate 26 and the topside of upper insulation block 20. An annular seal 28 embedded in the bottom side of cover 23 vacuum seals chamber 14 at the top rim of wall 13.
A vacuum tube 28' connected to a vacuum apparatus extends through the top of cover plate 23, through upper clearance 26 where the tube is in fluid connection with chamber 14 at port 32. A cylindrical ceramic table having a table top 36 is positioned in the lower portion of chamber 14 spaced below insulation block 20 so as to define a heating chamber 14A in chamber 14 between planar surface 21 of insulation block 20 and table top 36. Heating chamber 14A is about 6 inches in length. A lower annular space, or clearance, 38 formed between inner surface 18 of wall 13 and cylindrical table 34 extends to a bottom cover plate 40 that extends across the open bottom end of tube 12. An elevator, or lift, 42, which includes bottom cover plate 40, is raised and lowered by a vertical lifting piston 45 comprising a stack of rings operated by lifting machinery (not shown) in turn raises and lowers table 34 between the raised position shown in FIG. 1 and a lowered loading position shown in phantom line as lift 42A with table 34A, bottom cover plate 40A and piston 45A. An annular seal 44 embedded in the top side of bottom cover plate 40 vacuum seals chamber 14 when lift 42 is in the raised position.
A generally cylindrical outer insulation block 46, which comprises a stack of separate insulation rings, is positioned around tube 12 and is attached to upper and lower portions of wall 13. Tube 12 has a longitudinal dimension which has an imaginary center plane 48 that is perpendicular to the axis 49 of tube 12. The longitudinal dimension of tube 12 is divided into equal upper and lower portions 50 and 52 on either side of center plane 48. Insulation block 46 includes a series of preferably separate upper and lower insulation rings around tube 12 relative upper and lower portions 50 and 52. Upper insulation rings include upper first, second and third insulation rings which are slightly spaced from outer surface 16 so as to form upper first, second, and third annular clearances 54, 56, and 58, respectively, which are defined by the inner surfaces of the upper first, second, and third insulation rings and outer surface 16 of wall 13.
In a similar manner, lower insulation rings are slightly spaced from outer surface 16 so as to form annular lower first, second, and third annular clearances 60, 62, and 64, respectively, which are defined by the inner surfaces of the lower first, second, and third insulation rings and outer surface 16 of wall 13. An annular central chamber, or clearance, 66 that extends equally from either side of central plane 48 is defined by the inner diameter, or surface, of the center ring portion of insulation block 46 and outer surface 16 of wall 13; the inner diameter of outer insulation block 46 at this point is greater than the inner diameters of insulation block 46 at the upper and lower insulation rings so that central clearance 66 is larger than the other clearances. A plurality of vertically extending heating elements 68 extend through the upper portion of outer insulation block 46 so that the heating elements are positioned in central clearance 66 at equal intervals around tube 12. A dental reconstruction device 70 is shown in phantom line position on table top 36, which is preferably positioned at the same distance from central plane 48 as is bottom surface 21 if inner insulation block 20 from central plane 48.
Upper first, second, and third clearances 54, 56, and 58 have outside diameters at the inner surfaces of the upper first, second, and third rings of insulation block 46, each successive respective diameter being suitably less than the prior diameter, so that upper first, second, and third clearances 54, 56, and 58 are successively reduced in volume. With this configuration, direct thermal radiation from heating elements 68 to annular clearance 54 is reduced somewhat, and direct thermal radiation to upper annular clearance 56 and lower clearance 62 is greatly reduced. Finally, direct thermal radiation from heating elements 68 to upper clearance 58 and lower clearance 64 is totally blocked. Direct radiation to the clearances mentioned is partially or totally blocked as the case may be by the inner surface of the first, second, and third rings of outer insulation block 46. In addition, during the heating mode of furnace 10, air in central clearance 66 is heated to a very high temperature so that some heat passes from the air to wall 13 of tube 12, although air heating is incidental to the heating of tube 12. Because of convection, conduction, and radiation from the gas, heat reaches into the depths of the clearances, including clearances 58 and 64. It is to be noted that the clearances is to pass significant amounts of heat to wall 13 during the heating mode, but at a slightly reduced rate than heat passed to the walls of furnace area 14A. In addition, the clearances also pass heat along a longitudinal area of the wall 13 at a thermal gradient which is well within the temperature differential that the wall material 13 can tolerate without cracking during the heating mode.
The clearance between outer surface 16 of wall 13 of tube 12 and the inside diameter of outer insulation block 46 varies from large to small to zero over the insulated length of the tube taken from center plane 48 with the largest clearance being at the hot zone at central clearance 66. It is to be noted that although the clearances are shown as a series of stepped clearances, it is possible and within the scope of the invention to have a continuous angled, or tapered, inner surface along the inner surface of insulation block 46 rather than the separate rings forming the steps shown, provided that the proper amount of direct radiation from heating elements is blocked from wall 13 in the same manner described with respect to the stepped clearances noted hereinabove.
During the heating mode of furnace 10, wall 13 of tube 12 will be receive radiant energy from heating elements 68. This energy will be transmitted by radiation through vacuum chamber 14A to dental reconstruction device 70. The preferable temperature at the dental device is about 1200° C. Wall 13 is heated to about this temperature at the area around center plane 48. Conductive heat will pass along wall 13 from either side of center plane 48 to the upper and lower rim areas of wall 13. The upper and outer end portions of wall 13 extend somewhat, preferably about 1 inch, beyond outer insulation block 46 so that energy at those areas is allowed to pass directly into the atmosphere at these uninsulated portions so as to accelerate heat reduction at the seals to below the maximum use temperature of the seals. It is noted that conduction along wall 13 will transfer heat from the area of chamber 14a towards the opposed rims of wall 13. Finally, convection of heated air in the clearances will pass heat to wall 13. These factors all contribute and enter into the overall analysis concerning the configuration and dimensions of the various stepped clearances.
A broad calculation of the thermal gradient required with outer insulation block 46 is as follows. The temperature in the working heating chamber 14A is about 1200° C. The preferable maximum temperature at the end seals 28 and 44 is about 150° C., which leaves a temperature reduction of about 1050° C. in the 7 inches between each end of heating chamber 14A and end seals 28 and 44 with the result that the temperature gradient of each of those 7 inches is not greater than 150° C. per inch, which is well within the thermal shock resistance characteristic, or thermal endurance of tube 12 so as to avoid cracking of tube 12.
Tube 12 is preferably made of a material that has a low thermal conductivity, such as a ceramic. Ceramics, however, compared to other materials, such as metals, and the like, have a relatively low thermal shock resistance characteristic. One material that has been found to be satisfactory is mullite, a mixture of alumina and silica (3Al 2 O 3 ·SiO 2 ). Other materials having similar characteristics could be used, such as alumina or zirconia.
Reference is made herein to a test made on a prototype model of the invention, which is illustrated in FIG. 2, and shown partially in cross-section. As shown therein, the furnace 72 includes a cylindrical muffle tube 74 having a top cover 76 and having a vacuum seal 78 that seals the top rim of tube 74. Outer insulation block 80 forms upper and lower annular clearances 82 and 84, respectively, and central annular clearance 86 into which heating elements 88 extend is centered on the midplane 90. The dimensions as shown in FIG. 2 are 1/8 inch across and 2 inches longitudinally for upper clearance 82, 1/4 inch across and 1 inch longitudinally for lower clearance 84, and 71/4 inches inner diameter for center clearance 86. Measuring points for temperature during the heating mode were placed as follows: T1 at the bottom of bottom clearance 84; T2 at the bottom of clearance 82; T4 at the top of clearance 82; T5 midway between T4 and the top rim of tube 74 at seal 78; and T6 at the top rim of tube 74 at seal 78. The distance between T1 and T6 is 7 inches; between T3 and T6 is 5 inches; and between midplane 90 of furnace model 72 and T3 is 2 inches. Furnace prototype model 72 was heated and temperature measurements were taken at points T1, T2, T3, T4, T5, T6 with the results shown hereinbelow in Table I:
TABLE I______________________________________MUFFLE TUBE TEMPERATURE °F. (°C.)TIME T1 T2 T3 T4 T5 T6______________________________________ 0 661 575 460 352 266 123 (349) (302) (238) (178) (130) (51) 2 817 598 469 360 275 128 (436) (314) (243) (182) (135) (53) 4 916 649 490 375 285 134 (491) (343) (254) (191) (141) (57) 6 * 778 548 404 305 143 (414) (287) (207) (152) (62) 8 1569 992 674 471 348 154 (854) (533) (357) (244) (176) (68)10 1802 1245 865 586 415 163 (983) (674) (463) (308) (213) (73)12 1975 1480 1092 750 510 175 (1079) (804) (589) (399) (266) (79)14 2101 1676 1312 956 629 188 (1149) (913) (711) (513) (332) (87)16 1943 1721 1445 1123 733 177 (1062) (938) (785) (606) (389) (81)18 1785 1666 1445 1176 776 170 (974) (908) (791) (636) (413) (77)21 1613 1559 1402 1165 800 166 (878) (848) (761) (629) (427) (74)22 1563 1521 1375 1150 791 166 (851) (827) (746) (621) (422) (74)26 1415 1389 1269 1069 755 166 (768) (754) (687) (576) (402) (74)30 1302 1282 1174 922 707 168 (706) (694) (634) (533) (375) (76)______________________________________ *No data
TABLE II______________________________________THERMAL GRADIENT °F./inch; (°C./inch)TIME T1-T2 T2-T3 T3-T4 T4-T5 T5-T6______________________________________ 0 86 115 108 43 72 (43) (64) (60) (24) (40) 2 219 129 109 43 74 (122) (72) (61) (24) (41) 4 267 159 115 45 76 (148) (88) (64) (25) (42) 6 * 230 144 50 81 (128) (80) (28) (45) 8 577 318 203 62 97 (321) (177) (113) (34) (54)10 577 380 279 86 126 (309) (211) (155) (48) (70)12 495 388 342 120 168 (275) (216) (190) (67) (93)14 425 364 356 164 221 (236) (202) (198) (91) (123)16 222 276 322 195 278 (123) (153) (179) (108) (154)18 119 211 279 200 303 (66) (117) (155) (111) (168)21 54 157 237 183 317 (30) (87) (132) (101) (176)22 42 146 225 180 313 (23) (81) (125) (100) (174)24 26 120 200 157 295 (14) (67) (111) (87) (164)30 20 108 182 143 270 (11) (60) (101) (79) (150)______________________________________ *No data
In the prototype furnace tested, the end temperature is shown to have risen to 87° C. (188° F.), which is below the 200° C. (392° F.) maximum use temperature of any silicone rubber seal positioned at the ends of the muffle tube.
High temperature furnaces using conventional construction cool down very slowly. This is particularly the case when the tube cannot be opened and flushed with a cooling gaseous medium, which is the case with furnace 10. The metal sintering process is carried out in furnace 10 at temperatures up to 1200° C. and at vacuums of 100 microns (100 millitorrs) or less. After the alloy is sintered, furnace 10 cannot be opened until the internal temperature in the tube falls below the oxidation temperature of the sintered alloy. Typically this may require a drop of 500° to 600° C. in the furnace. Cooling the entire furnace by blowing air over the entire surface of prior art furnaces is not possible because of the insulation surrounding the heating elements and heating chamber. The prevention of heat losses during heating by means of the insulation also prevents effective cooling by cooling the external surfaces. The time of the cooling cycle is directly related to the rate of production of the work being processed by increasing the use time of the furnace in a production day.
This invention overcomes the problem by introducing compressed air during the cooling phase at several inlet ports A in insulation 46 opening into the lower clearances, optionally into lower clearance 62 as shown in FIG. 1. The compressed air escapes at several outlet ports B in insulation 46 opening into a clearance spaced from clearances A, optionally central clearance 66. Some of the compressed cooling air will also escape from upper and lower annular clearances C and D between tube 12 and insulation 46 where the fit, although tight, is not tight enough to prevent some air under pressure from passing from the clearances. Ports A are small, in the order of 1/4 inch diameter, and ports B are preferably smaller, in the order of 1/8 inch diameter in order to prevent excessive heat loss during the heating mode. It is desirable to use oil-free air for the cooling process so as to prevent the contamination of heating elements 68 and the outside of tube 12. The cooling process is done while the high vacuum in tube 12 is maintained. This inventive feature reduces the cooling time of the sintering process in the range of 30 percent as compared to the prior art method of merely directing air from a blower to cool the exposed outer surface of the furnace.
It is to be understood that the invention particularly described herein is not to be considered limited to the details set forth above, but that if various modifications and changes of the embodiment described occur to those skilled in the art, these are to be regarded as within the scope of the invention as defined by the appended claims.
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A vacuum furnace for heating dental reconstructionproducts using sintered powder metal that includes a sealed vacuum tube made of a material having a relatively low thermal shock resistance characteristic. The vacuum tube is desirably relatively short. The vacuum tube chamber has a heating chamber and end seals for the vacuum tube have a maximum use temperature of less than 200° C. Insulation is positioned around and connected to the tube proximate the ends of the tube, and heating elements are placed around the heating chamber in an annular insulation chamber formed in the insulation between the insulation and the vacuum tube. Opposed annular clearances extending to positions proximately spaced from the ends of the tube and opening to the central annular insulation chamber are formed between the insulation means and the vacuum tube. The insulation prevents heat from passing to the ends of the tube and overheating the seals there. The annular clearances controls the rate of heat emanating from the heating elements during the heatng process so that the heat generated by the heating elements is absorbed by the tube at a gradual controllable temperature gradient along the length of the tube that is less that the rate of heat gain that would be beyond the tolerance of the thermal shock resistance characteristic of the tube, so that cracking of the tube during heating is avoided.
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BACKGROUND OF THE INVENTION
[0001] This invention relates to a sleeve attachment system and method for more precise and rapid preparation of overdentures and an implant borne bar system infrastructure used to support an overdenture.
[0002] A large percentage of senior citizens in the United States are edentulous and many wear complete dentures, which rely on the oral tissues for support, retention and stability of their prostheses. However, these individuals face decreasing retention and stability of the dentures because of bone resorption. With the advent of bone-implantable anchors, known commonly as dental implants or implants, the edentulous patient can now enjoy the benefits of a fixed/removable prosthesis or overdenture borne by implants. This type of overdenture is fixed in that there is no restriction on chewing, yet still removable to facilitate hygiene. Unfortunately, the present methods for securing an implant borne overdenture are neither simple nor cost effective, thereby effectively making them unavailable to many patients.
[0003] In addition to being complicated and cost prohibitive, the present systems and methods for preparing and installing an overdenture and an implant borne infrastucture to support that denture are time consuming for the dentist, the dental Laboratory and the patient. Because the effectiveness, comfort and function of an implant borne overdenture depends to a great deal on the fit between the bar system infrastructure supported by the implants and the overdenture itself, a great deal of time must be spent to insure that whatever attachments are used to secure the overdenture to the bar system are in alignment with the bar system and engage properly. Inaccuracies in attachment can lead to movement of the overdenture in place and cause unwanted stress, torque and lateral movement of the implants, which may lead to their failure. Implants are essentially designed to be loaded along their longitudinal axis and not in the transverse direction. Because most of the present attachment systems cannot insure such unwanted movement in the implants, a period of several months time must lapse between actual insertion of the implants and fitting of a bar system and overdenture. This time is required to allow for osseointegration, which provides some ability to withstand transverse loading, which could result from unstable attachment systems.
[0004] While overdentures can be made such that the base of the overdenture contains a continuous attachment system which engages the bar system throughout its entire length, this type of attachment is extremely costly because of the alloys used.
SUMMARY OF THE INVENTION
[0005] It is an object of the present invention to provide a new and improved sleeve attachment system and method at less cost for more precise and rapid preparation of overdentures and an implant borne bar system for support of overdentures.
[0006] It is a further object of the present invention to provide a stable attachment system without the need for a continuous attachment system cast into an overdenture, which will reduce unwanted transverse loading of the implants with reduced time between insertion of the implants and fitting of a bar system borne by the implants to support an overdenture.
[0007] In accordance with the foregoing and other objectives of the invention, a new sleeve attachment system for use in preparation of overdentures and an implant borne bar system infrastructure used to support an overdenture is provided. The sleeve attachment system comprises; (a) at least one elongate bar with a through aperture for attachment to a distal end of the bar system infrastructure; (b) at least one sleeve, for integral casting into the underside of the overdenture, said sleeve being pre-fitted to receive the elongate bar and matched to the elongate bar as a set; (c) at least one retractable locking device fixedly attached to the sleeve and aligned to engage the through aperture in the matched elongate bar. It is a further object of this invention that this system be applicable to either the right or left distal end or both distal ends of a bar system infrastructure and the corresponding location or locations on the underside of an overdenture.
[0008] In an alternative embodiment of the sleeve attachment system, the retractable locking device comprises a swing blade pivoted in the sleeve to engage the through aperture in the elongate bar and engages the through aperture in the elongate bar from either the lingual side or the buccal side of the overdenture.
[0009] In a further alternative embodiment of the sleeve attachment system, the retractable locking device comprises a locking pin to engage the through aperture in the elongate bar and engages the through aperture in the elongate bar from either the lingual side or the buccal side of the overdenture.
[0010] It is a further object of this invention that the sleeve attachment system be applicable to either the right or left distal end or both distal ends of a bar system infrastructure and the corresponding location or locations on the underside of an overdenture.
[0011] It is also an object of the invention that the sleeve attachment system be applicable to both the upper and lower jaw.
[0012] It is a further object of the present invention that the sleeve attachment system be used in combination with at least one clip type attachment system on the anterior portion of a bar system infrastructure and the corresponding location or locations on the underside of an overdenture. In a further embodiment, the clip type attachment system comprises a ball and socket attachment system.
[0013] It is also an object of the present invention to provide a method for use in preparation of overdentures and an implant borne bar system infrastructure used to support an overdenture by (a) providing at least one elongate bar for attachment to the distal end of the bar system infrastructure as an integral part of the bar system infrastructure; (b) providing at least one sleeve, for integral casting into the underside of the overdenture; (c) providing at least one retractable locking device for attachment to the sleeve; (d) fixedly attaching retractable locking device to sleeve; (e) prefitting sleeve to receive the elongate bar; (f) creating an aperture in the elongate bar in alignment with the retractable locking device attached to sleeve when the elongate bar is received in the sleeve; (g) providing the elongate bar with aperture and the sleeve with the attached retractable locking device as a matched set for use in preparation of overdentures and an implant borne bar system infrastructure used to support an overdenture; (h) attaching the elongate bar to a distal end of the bar system infrastructure as an integral part of the bar system infrastructure; (i) aligning the sleeve with attached retractable locking device on the matching elongate bar; (j) casting the sleeve with attached retractable locking device into the underside of the overdenture such that when overdenture is placed on bar system infrastructure, the matching elongate bar is received in the sleeve and the retractable locking device is in alignment with the aperture in the elongate bar allowing immediate engagement of the locking device without additional fitting or machining.
[0014] This method further comprises the step of providing at least one clip type attachment system on the anterior portion of the bar system infrastructure and the corresponding portion of the underside of the overdenture. In a further embodiment of this method, the clip type attachment system provided comprises a ball and socket attachment system.
[0015] It is a further object of this invention that this method be applicable to either the right or left distal end or both distal ends of a bar system infrastructure and the corresponding location or locations on the underside of an overdenture.
[0016] It is also an object of this invention that this method be applicable to both the upper and lower jaw.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 is a perspective view of a sleeve with attached pivoted swing blade attachment system in juxtaposition over a matched elongate bar.
[0018] FIG. 2 is a cross section view of a sleeve with attached pivoted swing blade attachment system.
[0019] FIG. 3 is a perspective view of a sleeve with attached locking pin attachment system in juxtaposition over a matched elongate bar.
[0020] FIG. 4 is a cross section view of a sleeve with attached locking pin attachment system.
[0021] FIG. 5 is a perspective view of a lower jaw with implants and abutments.
[0022] FIG. 6 is a perspective view of a dental cast with bar system infrastructure to be borne by implants.
[0023] FIG. 7 is a perspective view of an overdenture in juxtaposition over an implant borne bar system infrastructure in a lower jaw.
[0024] FIG. 8 is a view of the underside of an overdenture.
[0025] FIG. 9 is a cross section view of an overdenture at the location of a sleeve with attached pivoted swing blade.
DETAILED DESCRIPTION OF THE INVENTION
[0026] Referring now to the drawings, FIG. 1 shows a perspective view of a preferred embodiment of a sleeve 1 with an integrally cast retractable locking device 2 with a swing blade 3 on a pivot 4 with a removal groove 5 . One example of such a retractable locking device is the “Swivel Loc Attachment” manufactured by Attachments International, Inc. of San Mateo, Calif. Integral with the sleeve 1 is an opening 8 for movement of the swing blade 3 . It is intended that sleeve 1 will be cast into the underside of an overdenture supported by an implant borne bar system infrastructure. Since the base material of overdentures is typically cast in an acrylic compound, also shown on sleeve 1 are retention nodules 6 to enhance retention of the sleeve 1 when cast into the underside of an overdenture. In the sleeve 1 is a seating slot 7 with two side faces 14 and an upper face 15 . In juxtaposition below sleeve 1 is shown an elongate bar 9 with an upper face 11 , two side faces 12 and two end faces 13 . The seating slot 7 in the sleeve 1 is milled or cast to receive the elongate bar 9 so that the upper face 11 of the elongate bar 9 engages the upper face 15 of the seating slot 7 in the sleeve 1 and the side faces 12 of the elongate bar 9 each engage a respective side face 14 of the seating slot 7 in the sleeve 1 . Also shown in the elongate bar 9 is a through aperture 10 of such size and geometry to receive the swing blade 3 when engaged through the opening 8 in the sleeve 1 when the elongate bar 9 is received in the seating slot 7 of the sleeve 1 . The elongate bar 9 is intended to be attached distally to an implant borne bar system infrastructure for supporting an overdenture and therefore one end face 13 of the elongate bar 9 will be permanently attached to the implant borne bar system infrastructure. Among the methods available for such attachment would be soldering or laser welding. Once attached to the implant borne bar system infrastructure, the elongate bar 9 will become the distal bar on either the right or left side of the infrastructure and will be cantilevered from that end of the infrastructure. The elongate bar 9 would normally be of such nominal cross sectional dimensions as compatible with the normal wax bar matrices used to cast bar system segments and which are provided commercially in 1.9×4 mm, 2.2×6 mm and 1.6×8 mm sizes. Because of such cantilevered position, normal practice would generally require that the elongate bar 9 be no longer than 10 mm. In normal practice also, the sleeve 1 and the seating slot 7 would be shorter than the elongate bar 9 to facilitate installation and the depth of the seating slot 7 would be not necessarily be the same as the height of the elongate bar 9 .
[0027] It is an object of this invention that the seating slot 7 of sleeve 1 be machined to exactly receive an elongate bar 9 , and the through aperture 10 in the elongate bar 9 be machined to exactly receive the swing blade 3 of the retractable locking device 2 when engaged, and that such sleeve 1 and elongate bar 9 be furnished as a matched set. As shown in FIG. 1 , the sleeve 1 is cast integrally with the retractable locking device 2 and it is intended that the materials be of such precious metal alloys as are used in the bar system infrastructure.
[0028] FIG. 2 is a cross section of a sleeve 1 , with an integrally cast retractable locking device 2 with a swing blade 3 and an opening 8 for engagement of the locking device 2 . Also shown are the two sides faces 14 and the upper face 15 of the seating slot 7 intended to respectively engage the two side faces 12 and top face 11 of the elongate bar 9 when seated in the sleeve 1 .
[0029] FIG. 3 shows a perspective view of an alternate embodiment of a sleeve 16 with an attached retractable locking device 17 with a locking pin 18 . One example of this type of retractable locking device is the Swiss-Loc NG. The retractable locking device 17 could be cast integrally with the sleeve 16 or attached by soldering or laser welding. Integral with the sleeve 16 is an opening 25 for movement of the locking pin 18 . It is intended that sleeve 16 will be cast into the underside of an overdenture supported by an implant borne bar system infrastructure. Since the base material of overdentures is typically cast in an acrylic compound, also shown on sleeve 16 are retention nodules 6 to enhance retention of the sleeve 16 when cast into the underside of an overdenture. In the sleeve 16 is a seating slot 19 with two side faces 26 and an upper face 27 . In juxtaposition below sleeve 16 is shown an elongate bar 20 with an upper face 22 , two side faces 23 and two end faces 24 . The seating slot 19 in the sleeve 16 is milled or cast to receive the elongate bar 20 so that the upper face 22 of the elongate bar 20 engages the upper face 27 of the seating slot 19 in the sleeve 16 and the side faces 23 of the elongate bar 20 each engage a respective side face 26 of the seating slot 19 in the sleeve 16 . Also shown in the elongate bar 20 is a through aperture 21 of such size and geometry to receive the locking pin 18 when engaged through the opening 25 in the sleeve 16 when the elongate bar 20 is received in the seating slot 19 of the sleeve 16 . The elongate bar 20 is intended to be attached distally to an implant borne bar system infrastructure for supporting an overdenture and therefore one end face 24 of the elongate bar 20 will be permanently attached to the implant borne bar system infrastructure. Among the methods available for such attachment would be soldering or laser welding. Once attached to the implant borne bar system infrastructure, the elongate bar 20 will become the distal bar on either the right or left side of the infrastructure and will be cantilevered from that end of the infrastructure. The elongate bar 20 would normally be of such nominal cross sectional dimensions as compatible with the normal wax bar matrices used to cast bar system segments and which are provided commercially in 1.9×4 mm, 2.2×6 mm and 1.6×8 mm sizes. Because of such cantilevered position, normal practice would generally require that the elongate bar 20 be no longer than 10 mm. In normal practice also, the sleeve 16 and the seating slot 19 would be shorter than the elongate bar 20 to facilitate installation and the depth of the seating slot 19 would be not necessarily be the same as the height of the elongate bar 20 .
[0030] It is an object of this invention that the seating slot 19 of sleeve 16 be machined to exactly receive an elongate bar 20 , and the through aperture 21 in the elongate bar 20 be machined to exactly receive the locking pin 18 of the retractable locking device 17 when engaged, and that such sleeve 16 and elongate bar 20 be furnished as a matched set. As shown in FIG. 3 , it is intended that the materials be of such precious metal alloys as are used in the bar system infrastructure.
[0031] FIG. 4 is a cross section of a sleeve 16 , with an attached retractable locking device 17 with a locking pin 18 and an opening 25 for engagement of the locking device 17 . Also shown are the two sides faces 26 and the upper face 27 of the seating slot 19 intended to respectively engage the two side faces 23 and top face 22 of the elongate bar 20 when seated in the sleeve 16 .
[0032] FIG. 5 is a perspective view of the lower jaw 28 of an edentulous patient with four implants 30 fitted with abutments 31 in place to receive a bar system infrastructure to support an overdenture. Also indicated is the soft tissue 29 overlying the lower jaw 28 and the alveolar ridge 40 .
[0033] It should be noted that the position and placement of implants is determined by the surgeon and restorative dentist after evaluation of radiographs, the height of the alveolar ridge 40 , and the amount of bone available for implant 30 placement. A master cast of the patient's mandible or maxilla is made to prepare a working model of the planned implant placement from which a surgical guide stent will be made and a bar system will be cast. A surgical guide stent is prepared in a clear material on the cast. After determining the position of the implants, implant analogs are placed in the cast at the required position and used as a guide for drilling a hole through the clear surgical stent. This surgical stent is later used in the patient's mouth to guide the surgeon in drilling and placing the implants exactly as determined on the cast of the patient's mouth.
[0034] In addition to preparing the surgical stent from the patient's cast upon which implant analogs have been placed, the cast is used to prepare a bar system for support of an overdenture. FIG. 6 is a perspective view of a dental cast 32 , showing a cast bar system infrastructure 33 prepared for placement on abutments 31 on implants 30 in the patient's mouth. The bar system infrastructure 33 is cast in precious metal alloy from a wax cast built on the dental cast 32 . As shown in this embodiment, the distal ends of the bar system infrastructure 33 are not cast with the rest of the bar system infrastructure 33 but are rigidly attached after casting using elongate bars 9 with through aperture 10 . As previously discussed each elongate bar 9 is provided with a matching sleeve 1 with attached retractable locking device 2 .
[0035] FIG. 7 is a perspective view of a completed overdenture 34 with prosthetic teeth 35 and base 36 above an implant borne bar system 33 in a patient's mouth designed to receive and support the overdenture 34 . FIG. 8 is an underside view of the overdenture 34 , and the base 36 , showing the placement of integrally cast sleeves 1 with attached retractable locking devices 2 and a channel 39 to contain the bar system 33 . Also shown is an optional anterior socket 38 to receive a ball 37 on the bar system 33 to stabilize the anterior portion of the overdenture 36 . The anterior socket 38 and ball 37 are only one embodiment of a clip type attachment system, of which several are commercially available. As can be seen in FIG. 7 , the sleeves 1 will engage the elongate bars 9 on the bar system 33 allowing for engagement of the retractable locking device 2 in the through aperture 10 in the elongate bar 9 permanently attached to distal end of the bar system 33 . It is also seen that the ball 37 will engage the socket 38 .
[0036] FIG. 9 is a cross section view of the overdenture 34 at the location of the sleeve 1 with integral retractable locking device 2 with swing blade 3 , cast into the base 36 of the overdenture 34 , also showing the seating slot 7 to receive the elongate bar 9 and the opening 8 for engagement of the locking device 2 .
[0037] It is a further object of this invention that the machining and matching between sleeve 1 and elongate bar 9 or between sleeve 16 and elongated bar 20 be performed under what is commonly termed “precision” standards of machine tool quality. In existing practice, fitting an attachment sleeve to the distal bar of a bar system infrastructure is done to “semi-precision” standards in that the preparation of a through aperture to receive a retractable locking device is done by hand with the distal bar in place on a dental cast. By providing a matched set of sleeve with retractable locking device and elongate bar, the actual laboratory time needed to build and fit an overdenture and implant borne bar system to support the overdenture has been reduced by at least four to five hours, which time benefits the patient by reducing the number of office visits.
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A sleeve attachment system and method for more precise and rapid preparation of overdentures and implant borne bar systems used to support overdentures. The system includes an elongate bar and a prefabricated sleeve with an attached retractable locking device wherein the sleeve is precisely prefitted to receive the elongate bar and the retractable locking device is precisely aligned to engage the elongate bar through an aperture in the elongate bar when the elongate bar is seated in the sleeve. The elongate bar and the sleeve with an attached retractable locking device are assembled and milled as a matched set for inclusion and use in the preparation of an implant borne overdenture prosthesis system, with the elongate bar attached as a distal end of a bar system infrastructure fitted to implants and the sleeve with attached retractable locking device cast in the underside of the overdenture such that when the overdenture is placed over the bar system infrastructure, the elongate bar seats in the sleeve and the retractable locking device engages the elongate bar creating a stable support point for the overdenture.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a shutter panel. More particularly, it relates to a shutter panel in which a plurality of slats is connected in an aligned manner to be freely bendable by means of hinge mechanisms.
[0003] 2. Disclosure of the Prior Art
[0004] A shutter for opening and closing an aperture of a processing chamber installed with mechanical tools or an entrance of a building has already been proposed in an invention filed as Japanese Patent Application No. 2000-292689, and an embodiment thereof is a shutter of an arrangement as shown in FIG. 12.
[0005] In such an arrangement, both right and left ends of the shutter panel ( 10 ) obtained by connecting a plurality of slats ( 12 ) in an aligned manner to be freely bendable are held by guide rails ( 19 ) in a freely sliding manner, wherein an inner tube ( 16 b ) having a circular section and serving as a hinge member projects from one longer side of each slat ( 12 ) while an outer tube ( 16 a ) having a C-shaped section projects out from the other side of the slat ( 12 ). The outer tube ( 16 a ) can be outwardly fitted onto the inner tube ( 16 b ) in a freely rotating manner. The slat ( 12 ), the inner tube ( 16 b ) and the outer tube ( 16 a ) are integrally formed of a synthetic resin material.
[0006] With this arrangement, respective adjoining slats ( 12 ) are connected in a freely bendable manner by fitting the outer tube ( 16 a ) of one of the slats ( 12 ) to the inner tube ( 16 b ) of an oppositely disposed another slat ( 12 ) to be freely rotating. By sequentially performing these connecting processes, it is possible to complete the shutter panel ( 10 ) in which a plurality of slats ( 12 ) is connected in a freely bendable manner. When these right and left ends of the shutter panel ( 10 ) are held by a pair of guide rails ( 19 ) that are oppositely disposed at the aperture or the entrance, the aperture or the entrance may be closed and opened freely by means of the shutter panel ( 10 ).
[0007] However, since the slats ( 12 ), inner tubes ( 16 b ) and outer tubes ( 16 a ) were integrally formed of a synthetic resin material in the above prior art, the integrally molded body will shrink as a whole at the time of cooling and hardening of the resin immediately after the molding. Accumulation of shrinkage of all parts of the slats ( 12 ), the inner tubes ( 16 b ) and the outer tubes ( 16 a ) will easily lead to occurrence of dimensional errors, warpage or local irregularities in thickness of the entire integrally molded body. Accompanying such warpage or irregularities in thickness, it may happen that the outer tubes ( 16 a ) and inner tubes ( 16 b ) of adjoining slats ( 12 ) may not fit in a coaxial manner at high accuracy so as to prevent smooth relative rotation of the inner tubes ( 16 b ) and outer tubes ( 16 a ). Drawbacks were accordingly caused in that respective adjoining slats ( 12 ) could not be freely bend or in that the shutter panel ( 10 ) could not be smoothly opened and closed.
SUMMARY OF THE INVENTION
[0008] It is an object of the present invention to provide a shutter panel in which respective the longer sides of adjoining slats that are made of synthetic resin are connected by means of hinge mechanisms to be freely bendable, wherein smooth bending of the respective slats that are connected by the hinge mechanisms is enabled such that the shutter panel can be smoothly opened and closed by reducing warpage or irregularities in thickness of the slats or the hinge members for connecting these slats.
[0009] The shutter panel according to the present invention, which has been made for achieving the above objects, is characterized in that the hinge mechanisms include one hinge member and another hinge member, wherein each hinge member has a connecting groove that is opened outwardly, wherein the longer sides of the slats are fitted and coupled into and engaged with the connecting grooves respectively.
[0010] By fitting and coupling one of the longer sides of the slat with connecting groove of one of the hinge members while by fitting and coupling the other longer side of the slat with connecting groove of another hinge member, both hinge members are coupled to the both sides of the slat. By sequentially connecting a plurality of slats by using the hinge mechanisms included of both of these hinge members, the shutter panel is completed.
[0011] Since the respective hinge members and slats are constituted as separate members, warpage or local irregularities in thickness may be reduced that were caused through cooling and shrinkage after molding when compared to the above-described prior art in which all of these parts were molded in an integral manner.
[0012] Since warpage or irregularities in thickness of the respective parts owing to shrinkage by cooling may be prevented, it is further possible to prevent surfaces of the slats from slightly becoming wavy in case the slats are formed of transparent resin material, the transparency of the slats may be improved by reducing indiscriminate scattering of light hitting on the slats.
[0013] Because of the above arrangement, the present invention exhibits the following unique effects.
[0014] Since the slats and the hinge members are constituted as separate parts, the degree of shrinkage by cooling of resin at the time of molding can be reduced when compared to the prior art in which they were integrally molded so as to reduce warpage and local irregularities in thickness of the respective parts. Accordingly, respective adjoining slats may be connected by the hinge members to be smoothly bendable and warpage or torsion in the entire shutter panel may be prevented, and it is possible to smoothly open and close the shutter panel.
[0015] Other objects, features, aspects and advantages of the invention will become more apparent from the following detailed description of embodiments with reference to the accompanying drawings and appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] [0016]FIG. 1 is a front view of a housing ( 30 ) for machine tools to which the shutter according to a first embodiment of the present invention is applied.
[0017] [0017]FIG. 2 is a longitudinal sectional view of the housing ( 30 ) of FIG. 1.
[0018] [0018]FIG. 3 is a partial perspective view showing a condition in which an inner and outer tube ( 16 b )( 16 a ) are mounted onto a slat ( 12 ).
[0019] [0019]FIG. 4 is an enlarged end view of a portion at which the outer tube ( 16 a ) is disposed.
[0020] [0020]FIG. 5 is an enlarged end view of a portion at which the inner tube ( 16 b ) is disposed.
[0021] [0021]FIG. 6 is an explanatory view illustrating a condition in which the slats ( 12 ) are connected.
[0022] [0022]FIG. 7 is an explanatory view illustrating a condition in which the shutter panel ( 10 ) is assembled to guide grooves ( 42 ).
[0023] [0023]FIG. 8 is a front view illustrating a condition in which connecting tubes ( 61 ) are mounted to a slat ( 12 ) according to a second embodiment.
[0024] [0024]FIG. 9 is an enlarged view of a coupling portion between the slat ( 12 ) and the connecting tube ( 61 ) according to the second embodiment.
[0025] [0025]FIG. 10 is a view for explaining actions of a cover ( 65 ) formed on the connecting tube ( 61 ) applied in the second embodiment.
[0026] [0026]FIG. 11 is a view illustrating a condition in which the shutter panel ( 10 ) of the second embodiment is mounted to the guide rails ( 41 ).
[0027] [0027]FIG. 12 illustrates a Prior Art example.
DETAILED DESCRIPTION OF THE INVENTION
[0028] Embodiments of the present invention will now be explained with reference to the drawings.
[0029] (First Embodiment)
[0030] [0030]FIGS. 1 and 2 illustrate a shutter provided with the shutter panel according to the first embodiment of the present invention. The shutter panel ( 10 ) according to this embodiment is disposed to open and close an aperture of a housing ( 30 ), which is to serve as a processing chamber installed with mechanical tools, by being formed to extend from a front surface to an upper surface thereof, and both end edges of the shutter panel ( 10 ) are held by a pair of right and left guide rails ( 41 ), which are mounted to a frame body ( 32 ) of the housing ( 30 ), to be freely sliding in vertical directions.
[0031] The shutter panel ( 10 ) includes a plurality of slats ( 12 ) made of transparent synthetic resin and hinge members including an inner tube ( 16 b ) and outer tube ( 16 a ) that are attached to longer sides of the slats ( 12 ) respectively for connecting the longer sides of adjoining slats to be freely bendable each other.
[0032] As illustrated in FIGS. 3 and 4, the outer tube ( 16 a ) is a tubular body made of aluminum alloy with a C-shaped section, and is provided with a cylindrical main body ( 13 ) and a mounting block ( 20 ) having a connecting groove ( 21 ) on an outer peripheral surface thereof to project in an axial direction.
[0033] On opposing inner surfaces of a pair of projected pieces that constitute the connecting groove ( 21 ), engaging ribs ( 22 ) with triangular sections are formed to protrude from the entire connecting groove ( 21 ) along the axial direction to serve as protrusions for preventing slipping off. Engaging grooves ( 18 ) engaging with the ribs ( 22 ) are formed on front and back surfaces of the slat ( 12 ) along the longer side direction, wherein the sectional shape of the engaging grooves ( 18 ) is set to be somewhat smaller than the sectional shape of the engaging ribs ( 22 ).
[0034] With this arrangement, in case the longer sides of the slats ( 12 ) are inserted into the connecting grooves ( 21 ) of the mounting blocks ( 20 ) respectively, the engaging ribs ( 22 ) formed to project from opposing inner surfaces of the connecting grooves ( 21 ) are forcibly fitted with the engaging grooves ( 18 ) of the slats ( 12 ) so that the slats ( 12 ) are further inserted into the connecting grooves ( 21 ) in the fitted condition. At this time, since the engaging ribs ( 22 ) made of aluminum alloy cut into the front and rear surfaces of the slats ( 12 ) while slightly scraping inner surfaces of the engaging grooves ( 18 ) of the slats ( 12 ) made of synthetic resin that are formed to be slightly smaller, the engaging ribs ( 22 ) and engaging grooves ( 18 ) are fitted closely. In this condition, the mounting blocks ( 20 ) and slats ( 12 ) are fixedly attached through means such as high frequency welding or adhesive or the like.
[0035] The engaging grooves ( 18 ) that are formed on the front and rear surfaces of the slats ( 12 ) respectively are provided such that they are slightly shifted each other in shorter side directions of the slats ( 12 ). The reason for such an arrangement is that the thickness of the slats ( 12 ) at which the engaging grooves ( 18 ) are formed will become thinner to cause degradation in strength if the engaging grooves ( 18 ) on the front and rear surfaces would be formed at positions that are remote from the ends of the longer sides of the slats ( 12 ) by the same distance.
[0036] On the other hand, the inner tube ( 16 b ) is a tubular body made of aluminum alloy having a C-shaped section as illustrated in FIGS. 3 and 5, and is provided, similar to the outer tube ( 16 a ), with a cylindrical main body ( 14 ) and a mounting block ( 26 ) having a connecting groove ( 25 ) on an outer peripheral surface thereof to project in an axial direction, and is disposed on the other longer side of the slat ( 12 ) that is an opposite side attached the outer tube ( 16 a ). It should be noted that the inner tube ( 16 b ) might alternatively be of simple cylindrical shape.
[0037] The mounting block ( 26 ) is similarly arranged as the above-described mounting block ( 20 ) of the outer tube ( 16 a ), and engaging ribs ( 27 ) with triangular sections are formed to protrude along the axial direction of the inner tube ( 16 b ) on opposing inner surfaces of a pair of projected pieces that form the connecting groove ( 25 ). The relationship between the engaging ribs ( 27 ) and the engaging grooves ( 17 ) of the slats ( 12 ) are similar to those of the above-described outer tube ( 16 a ), and upon close fitting of the engaging ribs ( 27 ) into the engaging grooves ( 17 ) while cutting into the slats ( 12 ), they are fixedly attached through means such as high frequency welding or adhesive or the like.
[0038] The engaging grooves ( 17 ) are also formed at positions at which they are slightly shifted with respect to each other in shorter side directions owing to the same reason as that of the above-described outer tube ( 16 a ).
[0039] An outer diameter of the cylindrical main body ( 14 ) of the inner tube ( 16 b ) is set to be slightly smaller than an inner diameter of the cylindrical main body ( 13 ) of the outer tube ( 16 a ) so as to provide an arrangement in which the inner tube ( 16 b ) is inwardly fitted into the outer tube ( 16 a ) as illustrated in FIG. 6 wherein the outer tube ( 16 a ) and inner tube ( 16 b ) may freely rotate each other in a coaxial condition. When fitting the inner tube ( 16 b ) and the outer tube ( 16 a ) in a freely rotating manner, the mounting block ( 26 ) of the inner tube ( 16 b ) is set to project outwardly through the aperture ( 15 ) formed along the axial direction of the cylindrical main body ( 13 ) of the outer tube ( 16 a ). An aperture width for the aperture ( 15 ) and a thickness of the mounting block ( 26 ) are set such that the outer tube ( 16 a ) and the inner tube ( 16 b ) are allowed to relatively rotate by a certain angle.
[0040] For connecting the slats ( 12 ) by using hinge members that are formed of these inner tubes ( 16 b ) and outer tubes ( 16 a ), the inner tubes ( 16 b ) are attached to one of the longer sides of the slats ( 12 ) while outer tubes ( 16 a ) are attached to the other side as illustrated in FIGS. 3 and 6. More particularly, the longer sides of the slats ( 12 ) are forcibly fitted into the connecting grooves ( 25 )( 21 ) of the mounting blocks ( 26 ) ( 20 ) that are formed to project from the outer peripheral surfaces of the inner tubes ( 16 b ) and outer tubes ( 16 a ) for outwardly fitting and fixing.
[0041] Next, the cylindrical main body ( 14 ) of the inner tube ( 16 b ) mounted to one of the adjoining slats ( 12 ) is inserted into the cylindrical main body ( 13 ) of the outer tube ( 16 a ) mounted to another slats ( 12 ) from an open end along with the axial direction for fitting the inner tube ( 16 b ) and the outer tube ( 16 a ).
[0042] Thereafter, upon press fitting end caps ( 99 ) of slightly larger outer diameter than the inner diameter of the cylindrical main body ( 14 ) onto both ends of the inner tubes ( 16 b ) (see imaginary line of FIG. 5), the cylindrical main body ( 14 ) will slightly increase in diameter such that the cylindrical main body ( 14 ) is inwardly contacting an inner peripheral wall of the cylindrical main body ( 13 ) of the outer tube ( 16 a ) to thereby decrease rattling.
[0043] In this manner, adjoining slats ( 12 ) may be connected in a freely bendable manner through hinge members that are formed of inner tubes ( 16 b ) and outer tubes ( 16 a ). By repeating these actions for connecting a plurality of slats ( 12 ), the shutter panel ( 10 ) in which the slats ( 12 ) are connected in a freely bendable manner may be completed.
[0044] Since the slats ( 12 ), inner tubes ( 16 b ) and outer tubes ( 16 a ) are composed to be of separate parts in the present embodiment, overall warpage or local irregularities in thickness or the like owing to shrinkage by cooling and can be prevented when compared to the prior art in which they are integrally formed.
[0045] Since the slats ( 12 ) are formed of a transparent synthetic resin material, it is possible to see through from the exterior for observing operational conditions of machinery tools installed in the interior of the housing ( 30 ) also when the shutter panel ( 10 ) is in a closed condition.
[0046] A pair of right and left guide rails ( 41 ) is mounted to lateral frames ( 31 ) forming the frame body ( 32 ) of the housing ( 30 ) for holding both ends of the shutter panel ( 10 ) in a freely sliding manner, wherein both ends of the shutter panel ( 10 ) are held by guide grooves ( 42 ) formed on opposing surfaces of the guide rails ( 41 ).
[0047] In such an arrangement, upon grasping a handle ( 44 ) provided at a lower end of the shutter panel ( 10 ) and pulling the same upward, the shutter panel ( 10 ) will be slid upward along the guide rails ( 41 ) as illustrated in FIG. 2. With this arrangement, the aperture of the housing ( 30 ) will be opened.
[0048] Since engaging ribs ( 22 ) ( 27 ) cutting into front and rear of the slats ( 12 ) are formed on opposing inner surfaces of the connecting grooves ( 21 ) ( 25 ) of the mounting blocks ( 20 ) ( 26 ) that are formed on the inner tubes ( 16 b ) and outer tubes ( 16 a ) in a projecting manner, the slats ( 12 ) will be coupled to the connecting grooves ( 21 )( 25 ) in an even firmer manner. Since the inner tubes ( 16 b ) and outer tubes ( 16 a ) are fitted to be freely rotating each other, it is possible to eliminate coupling members such coupling shafts for connecting the respective hinge members as it is the case in the second embodiment which will be discussed later in details, and thus to decrease the number of parts constituting the hinge mechanisms.
[0049] In the first embodiment, the lengths of the inner tubes ( 16 b ) and outer tubes ( 16 a ) are set to be coincident with the entire length of the longer sides of the slats ( 12 ), but it is alternatively possible to mount a plurality of outer tubes ( 16 a ) and inner tubes ( 16 b ), which are cut to be of shorter lengths of the entire length of the longer side, to the longer sides of the slats ( 12 ).
[0050] (Second Embodiment)
[0051] FIGS. 8 to 11 illustrate a shutter panel according to a second embodiment.
[0052] The shutter panel ( 10 ) of this embodiment is formed of a plurality of slats ( 12 ), connecting tubes ( 61 ) of C-shaped section serving as hinge members made of aluminum alloy that are mounted on the longer sides thereof at specified intervals, and coupling shafts ( 71 ) having a shape of a round pipe that are inserted into the connecting tubes ( 61 ) rotatably.
[0053] As illustrated in FIG. 8, the connecting tubes ( 61 ) are arranged in that connecting tubes ( 61 ) mounted to one longer side of a slat ( 12 ) and connecting tubes ( 61 ) mounted to the other side thereof are alternately provided. In the present embodiment, the connecting tubes ( 61 ) mounted to central portions of the longer sides of the slats ( 12 ) are set to be longer than the connecting tubes ( 61 ) that are mounted to the both ends of the longer sides of the slats ( 12 ). The reason for mounting the longer connecting tubes ( 61 ) to the central portions of the slats ( 12 ) is to improve reinforcing effects of the central portions of the slats ( 12 ) that are apt to be flexed in width directions.
[0054] The intervals between respective connecting tubes ( 61 ) are set such that connecting tubes ( 61 ) which are mounted to one of the longer sides of the slat ( 12 ) to be alternately formed with connecting tubes ( 61 ) mounted the other longer side of another slats ( 12 ) may just fit into spaces formed between respective connecting tubes ( 61 ).
[0055] As illustrated in FIG. 9, each cylindrical main body ( 63 ) of all of the connecting tubes ( 61 ) are formed to be of identical inner diameter and outer diameter, and their outer peripheral surfaces are formed with mounting blocks ( 64 ) that are similarly arranged to exhibit the same functions as the mounting blocks ( 20 )( 26 ) as already described with reference to the first embodiment. And cover pieces ( 65 ) projecting to a direction opposite to the above mounting blocks ( 64 ) are provided on the outer peripheral surface of the connecting tubes ( 61 ).
[0056] In case adjoining slats ( 12 ) are respectively arranged in a straight line, the cover piece ( 65 ) (of one slat) functions to abut an upper surface of an end portion of another slat ( 12 ) as illustrated by the broken line as illustrated in FIG. 10 for covering a clearance between the slat ( 12 ) and the connecting tube ( 61 ), respectively. As illustrated in FIG. 11, the cover piece ( 65 ) also acts as a brake for stopping unexpected movements of the shutter panel ( 10 ) by abutting against inner walls of arc-like curved portions of the guide rails ( 41 ).
[0057] In this arrangement, connecting tubes ( 61 ) mounted to one slat ( 12 ) are inserted between connecting tubes ( 61 ) mounted to another adjoining slat ( 12 ), and the above-described coupling shaft ( 71 ) is inserted into the connecting tubes ( 61 ) aligned in series. With this arrangement, adjoining slats ( 12 ) are respectively connected in a freely bendable manner via the connecting tubes ( 61 ).
[0058] It should be noted that while the cylindrical main bodies ( 63 ) of the connecting tubes ( 61 ) are formed to be of C-shaped sections in this embodiment, the cylindrical main bodies ( 63 ) might also be of simple cylindrical shape with no slits being formed on its outer peripheral surface. While the respective connecting tubes ( 61 ) are separated from each other, the connecting tubes ( 61 ) might also be integrated by means of clearance maintaining members to be aligned in an axial direction at specified intervals.
[0059] [Others]
[0060] While the inner tubes ( 16 b ), the outer tubes ( 16 a ) and the connecting tubes ( 61 ) constituting the hinge members are formed of aluminum alloy in the above-described embodiments, they may alternatively be formed of other metals or synthetic resin materials.
[0061] While the above-described embodiments employ an arrangement in which engaging grooves ( 17 )( 18 ) are formed on front and rear surfaces near the longer sides of the slats ( 12 ) and in which engaging ribs ( 22 ) ( 27 ) for fitting into and engaging with the engaging grooves ( 17 ) ( 18 ) are formed on the inner tubes ( 16 b ), the outer tubes ( 16 a ) or the connecting tubes ( 61 ) sides, it is not necessarily required to form the engaging grooves ( 17 ) ( 18 ) on the end edges of the slats ( 12 ). It is alternatively possible to employ an arrangement in which the inner tubes ( 16 b ), the outer tubes ( 16 a ) or the connecting tubes ( 61 ) are formed of metallic materials wherein the engaging ribs ( 22 ) ( 27 ) are formed to be of sharp triangular sectional shape so that the sharp tip ends of the engaging ribs ( 22 ) ( 27 ) will cut into the front and rear of the slats ( 12 ) to prevent slipping off when the ends of the slats ( 12 ) are forcibly inserted into the connecting grooves ( 21 ) ( 25 ).
[0062] Another alternative would be an arrangement in which engaging ribs are formed on front and rear surfaces of the slats ( 12 ) while engaging grooves ( 17 )( 18 ) are formed on connecting grooves ( 21 )( 25 ) of the inner tubes ( 16 b ), the outer tubes ( 16 a ) or the connecting tubes ( 61 ) for engaging with the engaging ribs ( 22 )( 27 ).
[0063] It is not necessarily required to form the inner tubes ( 16 b ), the outer tubes ( 16 a ), the connecting tubes ( 61 ) and the slats ( 12 ) with the engaging ribs ( 21 ) ( 27 ) or engaging grooves ( 17 ) ( 18 ).
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A shutter panel ( 10 ) in which respective longer sides of slats ( 12 ) made of synthetic resin are connected through hinge mechanisms to be freely bendable manner, wherein the hinge mechanisms include one hinge member and another hinge member. Each hinge member has a connecting groove that is opened outwardly. By fitting and coupling the longer sides of the slats into the connecting grooves respectively, smooth opening and closing of the shutter panel ( 10 ). can be performed because of decreasing warpage or irregularities in thickness of slats ( 12 ) or the hinge members and enabling smooth bending of respective slats ( 12 ) connected by the hinge mechanisms.
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CROSS REFERENCE TO RELATED APPLICATION(S)
[0001] This application claims the benefit of provisional application Ser. No. 61/781,778, filed Mar. 14, 2013.
STATEMENT OF GOVERNMENT INTEREST
[0002] The Government of the United States of America may have rights in the present invention as a result of NASA Cooperative Agreement Contract No. NNX11AB35A and Sub-Contract No. MIT/PW Subaward No. 5710002937 awarded by NASA.
BACKGROUND
[0003] The present disclosure is directed to a variable cycle intake for a propulsion system having a reverse core engine, which variable cycle intake has a first position for supplying free stream air to an inlet of the engine and a second position for supplying fan stream air to the inlet of the engine.
[0004] Typical multi-spool turbofan engines include a nested core, in which a high pressure, or core, spool is nested inside a low pressure spool. Such a nested core engine includes, in axial sequence, a low pressure compressor, a high pressure compressor, a combustor section, a high pressure turbine, and a low pressure turbine. The high pressure compressor is connected to the high pressure turbine with a high pressure shaft that extends through the combustor section. The low pressure compressor is connected to the low pressure turbine with a low pressure shaft that extends through the high pressure shaft. Increases in efficiency of the turbofan allow for the core to be reduced in size, such as by having a smaller diameter. The low pressure shaft, however, cannot be reduced in diameter because the rotational speeds of the low pressure spool are limited by critical speed. The shaft critical speed is proportional to the shaft diameter and inversely proportional to the shaft length. Thus, decreasing the shaft diameter with reduced core sizes is not possible without reducing the shaft length if the same critical speed is desired. Thus, reductions in the core size yields compromises in the high pressure spool to accommodate low pressure spool shaft diameters. For example, the size and weight of high pressure spool rotor disk need to be increased to accommodate openings for larger low pressure shaft sizes. As such, there is a need for improving engine architectures to allow for, among other things, decreased core sizes resulting from more efficient turbofan engines.
[0005] There has been proposed a gas turbine engine comprising a fan drive gear system, a low spool connected to the fan drive gear system, and a high spool disposed aft of the low spool. The low spool comprises a rearward-flow low pressure compressor disposed aft of the fan drive gear systems, and a forward flow low pressure turbine disposed aft of the low pressure compressor. The high spool comprises a forward flow high pressure turbine disposed aft of the low pressure turbine, a combustor disposed of aft of the high pressure turbine, and a forward-flow high pressure compressor disposed aft of the combustor.
[0006] One issue faced by designers of these new engine architectures is incorporation of the new engine architecture into an aircraft.
SUMMARY
[0007] In accordance with the present disclosure, there is provided a gas generator for a reverse core propulsion system, which broadly comprises a variable cycle intake for the gas generator, said variable cycle intake comprising a duct system which is configured for being selectively disposed in a first position and a second position, wherein free stream air is fed to the gas generator when in the first position and fan stream air is fed to the gas generator when in a second position.
[0008] In another and alternative embodiment, the duct system includes a free stream air inlet, a duct extending from the free stream air inlet, a slidable duct, a curved duct segment, and an outlet duct section.
[0009] In another and alternative embodiment, the slidable duct moves between a first position where the slidable duct communicates with the curved duct segment and a second position where the slidable duct is out of communication with the curved duct segment.
[0010] In another and alternative embodiment, the slidable duct surrounds a portion of the duct extending from the free stream air inlet.
[0011] In another and alternative embodiment, the curved duct segment surrounds a portion of the outlet duct section.
[0012] In another and alternative embodiment, the outlet duct section supplies one of free stream air and fan stream air to the gas generator.
[0013] In another and alternative embodiment, the outlet duct section is connected to an inlet of the gas generator.
[0014] In another and alternative embodiment, the gas generator further comprises a fan stream air inlet duct.
[0015] In another and alternative embodiment, the curved duct segment is moved from a free air stream position in contact with the slidable duct and out of contact with the fan stream air inlet duct to a fan air stream position in contact with the fan stream air inlet duct and out of contact with the slidable duct.
[0016] In another and alternative embodiment, the gas generator further comprises an actuator to move the curved duct segment from the free air stream position to the fan stream air position and from the fan stream air position to the free air stream position.
[0017] In another and alternative embodiment, the actuator has a first arm connected to a first surface of the curved duct segment and a second arm connected to a second surface of the curved duct segment.
[0018] In another and alternative embodiment, the gas generator further comprises a first link connected to the first surface of the curved duct segment and to a first surface of the slidable duct and a second link connected to the second surface of the curved duct segment and to a second surface of the slidable duct to move the slidable duct as the curved duct segment moves.
[0019] In another and alternative embodiment, the gas generator further comprises a particle separator connected to the free stream air inlet.
[0020] In another and alternative embodiment, the gas generator further comprises a cover plate for covering the free stream air inlet when the variable cycle intake is in the second position.
[0021] Further in accordance with the present disclosure, there is provided an aircraft which broadly comprises a fuselage having a tail section; a pair of gas generators located in the tail section; each of the gas generators having a variable cycle intake for supplying one of free stream air and fan stream air to a respective one of the gas generators; and variable cycle intake comprising a duct system which feeds free stream air to the respective one of the gas generators when in a first position and which feeds fan stream air to the respective one of the gas generators when in a second position.
[0022] In another and alternative embodiment, the duct system includes a free stream air inlet, a duct extending from the free stream air inlet, a slidable duct, a curved duct segment, and an outlet duct section.
[0023] In another and alternative embodiment, the slidable duct moves between a first position where the slidable duct communicates with the curved duct segment and a second position where the slidable duct is out of communication with the curved duct segment.
[0024] In another and alternative embodiment, the slidable duct surrounds a portion of the duct extending from the free stream air inlet.
[0025] In another and alternative embodiment, the curved duct segment surrounds a portion of the outlet duct section.
[0026] In another and alternative embodiment, the outlet duct section supplies one of free stream air and fan stream air to the respective one of the gas generators.
[0027] In another and alternative embodiment, each of the gas generators comprises a reverse core engine and the outlet duct section is connected to an inlet of the respective one of the gas generator.
[0028] In another and alternative embodiment, the duct system further comprises a fan stream air inlet duct.
[0029] In another and alternative embodiment, the curved duct segment is moved from a free air stream position in contact with the slidable duct and out of contact with the fan stream air inlet duct to a fan air stream position in contact with the fan stream air inlet duct and out of contact with the slidable duct.
[0030] In another and alternative embodiment, the duct system further comprises an actuator to move the curved duct segment from the free air stream position to the fan stream air position and from the fan stream air position to the free air stream position.
[0031] In another and alternative embodiment, the actuator has a first arm connected to a first surface of the curved duct segment and a second arm connected to a second surface of the curved duct segment.
[0032] In another and alternative embodiment, the duct system further comprises a first link connected to the first surface of the curved duct segment and to a first surface of the slidable duct and a second link connected to the second surface of the curved duct segment and to a second surface of the slidable duct to move the slidable duct as the curved duct segment moves.
[0033] In another and alternative embodiment, the duct system further comprises a particle separator connected to the free stream air inlet.
[0034] In another and alternative embodiment, the duct system further comprises a cover plate for covering the free stream air inlet when the variable cycle intake is in the second position.
[0035] In another and alternative embodiment, the duct system is at least partially embedded within an aerodynamic fairing.
[0036] In another and alternative embodiment, the aircraft further comprises a pair of free turbines and a pair of fans fan driven by said free turbines, wherein said gas generators provide air for driving said pair of free turbines.
[0037] Other details of the variable cycle intake for reverse core engines are set forth in the following detailed description and the accompanying drawings wherein like reference numerals depict like elements.
BRIEF DESCRIPTION OF THE DRAWINGS
[0038] FIG. 1A is a schematic representation of an aircraft having a propulsion system with two gas generators in the form of reverse core engines;
[0039] FIG. 1B illustrates a portion of the tail section of the aircraft of FIG. 1A ;
[0040] FIG. 2 is a sectional view of the propulsion system for propelling the aircraft of FIG. 1 ;
[0041] FIG. 3 is a sectional view of a fairing having the variable cycle intake embedded therein;
[0042] FIG. 4 is a schematic representation of the variable cycle intake in a first position where free stream air is supplied to a gas generator;
[0043] FIG. 5 is a schematic representation of the variable cycle intake of FIG. 4 in a second position where fan stream air is supplied to the gas generator;
[0044] FIGS. 6A-6C are schematic representation of the variable cycle intake as it moves from the first position to the second position;
[0045] FIG. 7 is a rear view of the propulsion system showing the fairing blended into a bi fi wall;
[0046] FIG. 8 illustrates the variable cycle intake in the first position;
[0047] FIG. 9 illustrates the variable cycle intake in the second position;
[0048] FIG. 10 illustrates the flow through the variable cycle intake when in the first position;
[0049] FIG. 11 illustrates the flow through the variable cycle intake when in the second position; and
[0050] FIG. 12 illustrates a cover which can be slid over an air inlet of the variable cycle intake when not in use.
DETAILED DESCRIPTION
[0051] FIGS. 1A and 1B illustrate an aircraft 10 having a fuselage 12 , wings 14 , and a tail 15 having vertical tail surfaces 16 and a tail wing 18 mounted to the tail surfaces 16 . A propulsion system having a pair of propulsors 20 , which are gas turbine engines, is mounted to the fuselage 12 at the base of the tail 15 . The inlet 44 to each of the propulsors 20 includes a channel 46 in the fuselage 12 for delivering atmospheric air to the propulsors 20 . An aerodynamic fairing 22 may extend from each side of the fuselage 12 adjacent the tail 15 .
[0052] Referring now to FIG. 2 , each of the propulsors 20 may comprise a propulsor section 23 which has a free turbine 52 , a fan 48 having a plurality of fan blades 49 which is driven by the free turbine 52 , and a plurality of fan exit guide vanes 47 . The free turbine 52 and the fan 48 rotate about a central axis 24 . Each of the propulsors 20 further has a gas generator 26 which has a longitudinal axis or central axis 28 which is at an angle to the fan central axis 24 .
[0053] The illustrated gas generator 26 is a reverse core engine which includes a compressor section 50 having one or more stages such as a low pressure compressor and a high pressure compressor, a combustion section 51 having one or more combustors, and a turbine section 53 having one or more stages such as a low pressure turbine and a high pressure turbine. The low pressure compressor in the gas generator 26 is driven by a low pressure turbine via a low pressure spool and a high pressure compressor in the gas generator 26 is driven by a high pressure turbine via a high pressure spool. The gas generator 26 delivers combusted fluid to the free turbine 52 , for driving same, via a plenum 55 connected to the outlet of the gas generator 26 . The free turbine 52 drives the fan 48 .
[0054] Referring now to FIG. 3 , there is shown a variable cycle air intake 60 which is at least partially embedded within the aerodynamic fairing 22 . As can be seen from FIG. 3 , the aerodynamic fairing has a leading edge 62 , a trailing edge 64 , an upper aerodynamic surface 66 , and a lower aerodynamic surface 68 .
[0055] Referring now to FIGS. 4 and 5 , the variable cycle intake 60 has a duct system which includes a free stream air inlet 70 , a duct 72 extending from the air inlet 70 , a slidable duct section 74 which surrounds a portion of the duct 72 and which moves relative to the duct 72 , a curved duct segment 76 , and an outlet duct section 78 which connects to an inlet of a low pressure compressor section of the gas generator 26 .
[0056] The curved duct segment 76 overlaps and surrounds a portion of the outlet duct section 78 . The curved duct segment 76 is movable relative to the outlet duct section 78 between a first position (see FIG. 4 ) and a second position (see FIG. 5 ). In the first position, the curved duct segment 76 is in communication with the slidable duct section 74 . In the second position (see FIG. 5 ), the curved duct segment 76 is in communication with a fan stream air inlet duct 80 .
[0057] As can be seen from FIGS. 4 and 5 , the curved duct segment 76 is rotated about an axis 82 by a U-shaped actuator 84 . As shown in FIGS. 6A-6C , the U-shaped actuator 84 has a first arm 86 connected to a first surface 88 of the curved duct segment 76 and a second arm 90 connected to a second surface 92 of the curved duct segment 76 . The actuator 84 may be rotated about the axis 82 by a motor (not shown) or any other suitable power source.
[0058] An upper link 94 is connected at a first end 96 to the first surface 88 of the curved duct segment 76 . At a second end 98 , the upper link 94 is connected to a first surface 95 of the slidable duct section 74 . As shown in FIG. 5 , a lower link 102 is connected to at a first end to the second surface 92 of the curved duct segment 76 . At a second end, the lower link 102 is connected to a second surface 108 of the slidable duct section 74 .
[0059] Referring now to FIGS. 6A-6C , as the actuator 84 rotates about the axis 82 towards the air inlet 70 , the rotation of the actuator causes the slidable duct section 74 to move from a first free stream air position to a second fan stream position. In the first fan stream position the slidable duct section 74 is in contact with the curved duct segment 76 . In the second fan stream position, the duct 74 is out of contact with the curved duct segment 76 .
[0060] When moving from the first position to the second position, the slidable duct section 74 moves relative to the duct 72 by siding in a direction toward the air inlet 70 and assume the position shown in FIG. 5 and FIG. 6C . As shown in FIGS. 6B and 6C , movement of the slidable duct section 74 creates a gap 110 which allows the curved duct segment 76 to rotate and come into fluid communication with the fan stream inlet duct 80 . When the curved duct segment 76 is in the position shown in FIG. 6C , fan stream air is supplied to the inlet of the gas generator 26 .
[0061] When the actuator 84 rotates about the axis 82 away from the air inlet 70 , the rotation of the actuator causes the curved duct segment 76 to rotate into the position shown in FIG. 4 and causes the slidable duct section 74 to slide over the duct 72 and into the position shown in FIG. 4 where the slidable duct section 74 is in communication with the curved duct segment 76 and the curved duct segment is out of contact with the fan stream inlet duct 80 . In this position, free stream air is provided to the inlet of the gas generator 26 .
[0062] The variable cycle intake 60 may include a particle separator 112 (see FIG. 3 ) which separates solid particles from the free air stream. The particle separator 112 may be provided with a first, upstream outlet that communicates with an internal channel 114 and a second downstream outlet 116 in the external lower aerodynamic surface 68 . Particles within the free air stream tend not to follow the curvature of the intake 30 and continue on straight into the particle separator 112 .
[0063] As shown in FIG. 7 , the aerodynamic fairing 22 may be blended into a bi-fi wall 118 surrounding the core 120 of the gas generator 26 .
[0064] FIGS. 8 and 10 illustrate the variable cycle intake 60 in a first position where free air stream may be provided to a low pressure compressor section of the gas generator 26 .
[0065] FIGS. 9 and 11 illustrate the variable cycle intake 60 in a second position where fan air stream may be provided to the low pressure compressor section of the gas generator 26 .
[0066] As shown in FIG. 12 , a cover plate 122 may be provided within the fairing 22 to cover the free stream air inlet 70 when the variable cycle intake 60 is in the fan stream air position. An actuator (not shown) may be provided to slide the cover plate 122 over the air inlet 70 .
[0067] The primary benefit of the variable cycle intake 60 is the dual cycle capability that it provides.
[0068] There has been provided in accordance with the present disclosure a variable cycle intake for a reverse core engine. While the variable cycle intake has been described in the context of specific embodiments thereof, other unforeseen alternatives, modifications, and variations may become apparent to those skilled in the art having read the foregoing description. Accordingly, it is intended to embrace those alternatives, modifications, and variations which fall within the broad scope of the appended claims.
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A gas generator for a reverse core engine propulsion system has a variable cycle intake for the gas generator, which variable cycle intake includes a duct system. The duct system is configured for being selectively disposed in a first position and a second position, wherein free stream air is fed to the gas generator when in the first position, and fan stream air is fed to the gas generator when in the second position.
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FIELD OF THE INVENTION
The present invention relates to the wood pulp and paper industry, and, more particularly, to a method for fiberboard manufacture.
This invention can be used to best advantage for the manufacture of fiberboards designed for wall, ceiling, and door cladding in the interior of rooms and railway cars, as well as for lightweight house building and furniture manufacture.
BACKGROUND OF THE INVENTION
The fabrication of fiberboard by the wet process (Thomas M. Maloney. Modern Particleboard and Dryprocess Fiberboard Manufacturing. Pullman, Wash., 1977) is known to make use of vegatable raw materials, viz. ground and suitably treated softwood, or hardwood, or mixtures thereof.
However this known method of fiberboard manufacture has an essential drawback in that it requires consumption in large quantities of wood presently available at high cost.
There is another known method for fiberboard manufacture, in which the consumption of high-cost wood is reduced by replacing it in part with additives, such as sawdust or bark (S. P. Rebrin. Tekhnologiya drevesnovoloknistykh plit (Fiberboard Technology). Lesnaya Promyshlennost Publishers, Moscow, 1982, pp. 5, 18, 19).
The use of wood processing or sawmilling wastes for the purpose of fiberboard manufacture by the wet process does make for a reduction in the consumption of expensive wood.
Yet the method in question is fraught with several difficulties. Thus, for example, the use of sawdust as an additive in fiberboard fabrication necessitates the use of specially designed grinding equipment, this raising the costs of and complicating the wet-process technology of fiberboard fabrication. Where bark is utilized as an additive, the quality of the fiberboard suffers, the detrimental effect being due to the bark moisture content normally not exceeding 20 percent. The relatively low moisture content of bark has a negative effect upon the quality of the fiber, with the fiberboard surface becoming non-uniform as a consequence. It is for this reason that the use of bark as a partial substitute for wood in fiberboard manufacture has but a limited scope of application.
Other partial substitutes for wood that can be used in fiberboard fabrication are sugar cane stems (USSR Pat. No. 211,452 dated 25.03.1966), hydrolysis lignin (USSR Inventor's Certificate No. 331,930 dated 25.12.1969), and activated sludge (USSR Inventor's Certificate No. 537,843 dated 23.05.1975).
The process that has the most widespread usage in fiberboard manufacture is the wet process using woodships as the principal raw material (S. P. Rebrin. Tekhnologiya drevesnovoloknistykh plit (Fiberboard Technology). Lesnaya Promyshlennost Publishers, Moscow, pp. 114-120).
This raw material is subjected to steam treatment in steaming units to be subsequently ground in mills. The wood pulp obtained as a result of woodship milling is additionally diluted with water to a concentration not exceeding 4 percent. Then the pulp is further ground and further diluted with water. The concentration of wood pulp in the water slurry thus obtained does not exceed 0.9 to 1.8 percent. In the sizing box, water-repellent agents are added to the water slurry, such as paraffin, oleic acid, sulphate soap, or a ceresin compound. The concentration of the water-repellent additive does not exceed 1 percent. The additive is introduced in the form of a finely dispersed emulsion. The emulsion envelopes wood fibers and fills the pores in the final product, preventing the ingress of moisture into the finished fiberboard. To assure a greater mechanical strength in fiberboard in the process of fabrication, binding agents are also added into the sizing box, such as, for example, phenol-formaldehyde resin, along with a suitable hardener, such as sulphuric acid. After mixing the aforesaid components in the sizing box, the resultant water slurry is cast over a wire screen, a fibermat forming upon the wire screen as a consequence. The mat is obtained in the following sequence of operations: pouring water slurry over the screen--filtering off water by gravity through the wire screen--removing water by suction with the aid of a vacuum unit and further by mechanical squeezing. As a result, a mat is obtained with a relative moisture content of about 80 percent. This is then forwarded to pressing rolls for edge trimming and further dewatering, with the relative moisture content being reduced here to 60 percent. This done, the fibermat is compacted at a temperature of 200° to 215° C. and a pressure of 5 to 5.5 MPa. In the compaction process, water is further removed so that the resulting fiberboard has a moisture content of 0.5 to 1.5 percent. To assure a high level of binder curing and thereby high strength characteristics, the compacted fiberboard is maintained in heat treatment ovens at a temperature of 160° to 170° C. for a period of four hours. Then the fiberboard is transferred to special chambers to be treated there with air having a relative humidity of 98 percent at a temperature of 65° C. The fiberboard thus acquires an uniform moisture content throughout and shows no tendency to surface warping while in storage.
For all that the method as described above also has a number of essential drawbacks. Apart from the large amount of high-cost wood to be used in the wet-process fabrication of fiberboard, there are also waste waters to cause environmental pollution, since these contain such highly toxic substances as phenol and formaldehyde which find their way into waste waters from the phenol-formaldehyde resin binder. Another disadvantage is the length of time consumed in maintaining fiberboard in heat treatment chambers where they acquire mechanical strength due to the curing of the binder at high temperature. The large period of time required for binder curing is due to the low concentration in the product of sulphuric acid used as cure catalyst, while the low catalyst concentration is due to losses caused by dissolving in and entrainment with waste waters. Incomplete curing of the resin imparts toxicity to the finished product. This toxicity is due to the presence of uncured phenol and formaldehyde which will evaporate from the product into the surrounding air. Emission of said components and their presence in the surrounding air will cause various diseases of allergic nature in human beings.
SUMMARY OF THE INVENTION
The present invention has for its object a reduction in the consumption of expensive vegetable raw materials in the process of fiberboard manufacture.
Another object of the present invention is a reduction in the concentration of toxic substances in the waste waters which originate from fiberboard fabrication by the wet process.
It is also an object of the present invention to reduce the emission of highly toxic phenol and formaldehyde from the finished product into the surrounding air.
A further object of the invention is to obtain fiberboards having high physical properties.
A still further object of the present invention is to improve the surface quality of the finished products without any additional treatment.
It is likewise an object of the present invention to increase the production efficiency and cut down the energy costs involved.
With these and other objects in view, there is provided a method for fiberboard manufacture comprising the steps of steaming and grinding woodchips to obtain a wood pulp, using said wood pulp to prepare a slurry of wood pulp in water, mixing said slurry with a binder, a cure catalyst for the binder, and a water-repellent additive, casting the mixture subsequently and dewatering it to obtain a mat, said mat being further compacted to give fiberboard which is subjected to heat treatment, wherein, according to the invention, 2.5 to 50 percent by mass of peat having a moisture content of 25 to 70 percent, with the ratio of absolutely dry peat to binder equal to between 1.0-7:1.0, respectively, is added to the mixture before casting, in the presence of 0.2 to 2.0 percent by mass of carbamide, with the carbamide-to-binder ratio equal to between 0.02-1.0:1.0 respectively. Peat is an organic fossil containing over 50 percent of mineral substances ("Prevrashcheniye torfa i yego komponentov v protsesse samorazogrevaniya pri khranenii" ("Conversions of peat and components thereof in the process of self-heating while in storage)". Edited by N. S. Pankratova. Nauka i tekhnika. Minsk, 1972, pp. 22, 23,81, 300).
Table 1 gives the composition of a peat that can be suitably used as an additive in fiberboard fabrication.
The vegetable fibers present in peat make good substitutes for expensive wood. They possess paper-forming properties which make it possible to obtain fiberboard featuring high strength characteristics.
The presence in peat of a large quantity of mineral substances which are capable of reacting chemically with phenol and formaldehyde, permits of binding free phenol and formaldehyde in inert compounds. Peat is also capable of sorbing chemical substances from waste waters, which allows of drastically reducing environmental pollution by harmful substances originating in fiberboard manufacture by the wet process.
The presence in the peat composition of humic and fulvic acids enables a higher binder curing level in the finished product and a shorter time period for binder curing. The explanation lies in the fact that weak organic acids, such as humic or fulvic acids, acquire high acidity at high temperatures and may thus serve the function of a substitute for sulphuric acid accepted here as hardener. A high binder curing level automatically results in higher mechanical properties in fiberboard and a lower concentration of free phenol and formaldehyde in the cured binder, with a consequently lower emission of said substances from the finished product into the surrounding air.
TABLE 1______________________________________ Concentration of peat components, % based on organic matter in peatCharacteristics top peat basin peat______________________________________Decomposition level % 5-15 20-25Water solubles at 50° C. 0.7-1.5 1.1-1.3Water solubles at 100° C. 1.5-3.6 2.3-3.1Easily hydrolyzable 25.4-46.7 24.8-33.4matter, includinghemicellulose 10.3-24.6 13.8-21.3Humic acids 8.5-16.5 28.3-36.4Fulvic acids 9.2-17.3 11.9-12.4Lignin (non-hydrolyz- 4.8-9.2 10.6-15.7able)Bitumens 4.8-10.1 10.6-15.7______________________________________
With the starting pulp for fiberboard preparation incorporating peat which is known to contain coloured compounds of natural origin, mineral salts, and bitumens, the fiberboards are obtained with a good surface requiring no further treatment with varnishes, lacquers, or paints. The presence in peat of easily hydrolyzable substances, as well as hemicelluloses, favours higher surface quality and higher mechanical properties in the finished product owing to the sizing effect produced by said compounds upon the product obtained. High strength, water resistance, a smooth and glossy surface featuring high aesthetical characteristics are among the properties of the fiberboards obtained.
Where peat is treated additionally with such a reagent as carbamide (NH 2 --CO--NH 2 ), the strength properties of fiberboard are further enhanced due to the chemical ability of carbamide to react with formaldehyde, as well as phenol. In this reaction, high-molecular-weight carbamide resins are formed to assure enhanced product strength and lower formaldehyde-to-air emission in consequence of the fact that formaldehyde is converted in this case to chemically bound state to a greater extent and thus is incapable of evaporating into the air.
In accordance with the invention, peat can be used conveniently for fiberboard fabrication without any preliminary drying in heat treatment chambers, which is advantageous economically. Under natural storage conditions, peat as excavated can have a moisture content ranging from 25-30 percent to 60-70 percent. Within this range, however, it retains its paper-forming properties while there occur undesirable conversion processes when peat is heated in the heat treatment chamber for drying. Table 2 contains some information concerning peat conversions at several temperatures.
TABLE 2______________________________________Loss of organic matter from peat Heating tem-on heating, % by mass perature, °C.______________________________________0.7 547.6 7910.1 81______________________________________
Within the temperature range of 140° to 150° C., peat undergoes degradation. Within the temperature range of 50° to 120° C. the losses in the chemical composition of peat are mainly at the cost of the carbohydrate complex.
We have discovered experimentally that peat having a moisture content of 25 to 70 percent, without undergoing any heat treatment, can be used for fiberboard fabrication by the wet process starting with a concentration of 2 to 3 percent. Where peat is used in quantities exceeding 50 percent by mass, it becomes necessary to increase the amount of phenol-formaldehyde resin in the product or else that of a water-repellent additive, to avoid an undesirable increase in the water absorption of the finished fiberboard.
However, using peat for fiberboard fabrication in high concentrations, close to 50 percent by mass, affords a drastic reduction in the quantity of chemical contaminants present in the waste waters, apart from replacing a considerable part of the raw materials of vegetable origin. Reduction in contaminants is based upon the well known ability of peat to well adsorb chemical substances, odours, and colorants. In the case under consideration the presence of carbamide in the starting pulp used for fiberboard fabrication is minimal.
Where peat is used in an amount of 2 to 20 percent by mass, carbamide addition should preferably by 0.2 to 2.5 percent by mass.
The use of carbamide is particularly advantageous where low peat concentrations are used for fiberboard fabrication.
The advantage inherent in the use of carbamide lies in the fact that carbamide enhances the binding function of peat with respect to formaldehyde. As far as peat itself is concerned, the inventors were the first in the world practice to discover its paper-forming properties. It is these properties that made it possible for the inventors to use peat as a partial substitute for wood in the wet-process fiberboard fabrication. Previously, when the paper-forming properties of peat were unknown, it was used only as a dry inert filler in the dry-process fiberboard manufacture.
DETAILED DESCRIPTION OF THE INVENTION
Softwood alone or in mixture with hardwood is ground after a preliminary heat treatment (steaming). Partial hydrolysis takes place in the process, with internal fiber surface development and fibers becoming more hydrophilic and plastic.
The water-saturated wood pulp obtained in the grinding process is further diluted to obtain a pulp-in-water slurry with a concentration of at least 4 percent by mass.
After a second grinding operation (refining), the wood pulp slurry is sent to a sizing box. Sizing favours lower water absorption and swelling, as well as higher mechanical strength in the finished fiberboard. Into the sizing box are added water-repellent agents, such as, for example, a paraffin emulsion in an amount not exceeding 1 percent (based on the absolutely dry fiber mass). To increase the mechanical strength of fiberboard, phenol-formaldehyde is used as binder, in a concentration of 10 percent and in an amount not exceeding 2 percent (based on the absolutely dry wood fiber mass), with sulphuric acid used as cure catalyst in an amount of 0.4 percent (based on the absolutely dry wood fiber mass) and in a concentration not exceeding 3 percent by mass.
In the sizing box, the wood pulp slurry is mixed with a peat-in-water slurry. To this end, peat having a moisture content of between 30 and 70 percent is diluted with water and passed through a screen filter whence it is fed to the sizing box in an amount of 2 to 50 percent by mass (based on the absolutely dry wood fiber mass).
After 0.2 to 2.0 percent by mass of carbamide is added into the sizing box, the mixture is stirred and fed by gravity into the head box of a forming machine. While in the pulp line and prior to delivery to the head box of the forming machine, the starting mixture is diluted with circulating or fresh water to a concentration of 1.8 percent maximum. The pH value in the head box is to be maintained not higher than 5.0.
The wood pulp slurry complete with the additives is cast over a wire screen whereon a 150 mm thick fibrous mat is obtained after excess water is removed by drainage through the screen, suction with the aid of a vacuum unit, and mechanical squeezing. The rate of wood pulp slurry pouring on to the wire screen is to be 5 to 10 percent lower than the screen speed. The moisture content of the mat downstream of the forming machine is not to exceed 73 percent.
Downstream of the forepresses, the resulting fiberboard is cut to size and sent for pressing at a temperature of 190° to 230° C. and a pressure of 5.0 to 5.5 MPa. Following the pressing stage the fiberboards are subjected to heat treatment for a period of 3.5 to 4 hours at a temperature not exceeding 168° C. After cooling the fiberboards to 40°-60° C., they are moistened to a moisture content of 6 to 10 percent and sent to the finished product storage.
The following parameters are used to control the quality of the finished products:
1. Ultimate flexural strength (MPa) as determined on a testing machine providing for a measuring error not exceeding 1 percent and a loading rate equal to 30 mm/min.
2. Water absorption in percent, for 24 hours, as determined by weighing.
3. Swelling in percent, for 24 hours, as determined by specimen thickness measurements.
4. Formaldehyde emission from the finished product, in mg/m 3 , as determined conventionally from the reaction between formaldehyde and phenylhydrazine hydrochloride in the presence of an oxidant in an alkaline medium.
5. Phenol emission from the finished product, in mg/m 3 , as determined conventionally from the reaction between phenol and diazotized n-nitraniline.
6. Formaldehyde concentration in waste waters, in mg/l, as determined conventionally by colorimetry using phenylhydrazine.
7. Phenol concentration in waste waters, in mg/l, as determined conventionally by colorimetry using diazotized n-nitraniline.
The following typical examples will serve to illustrate some aspects of the present invention and make more fully apparent specific features and advantages thereof.
EXAMPLE 1
Wood pulp prepared by grinding steamed woodchips to a freeness value of at least 14 defibrator-second was pumped into refiners. After grinding in the refiners, the pulp was fed by gravity into a continuous sizing box where it was diluted to a concentration of 2.8 mass %. Also added into the sizing box were a paraffin emulsion concentrated to 80 g/l and taken in the amount of 1% (based on the absolutely dry wood fiber mass), phenol-formaldehyde resin in the amount of 2% (based on the absolutely dry wood fiber mass), and sulphuric acid having a specific gravity of 1.012 and taken in the amount of 0.4% (based on the absolutely dry wood fiber mass). On mixing said components, carbamide was added to the mixture, in the amount of 2.0% (based on the absolutely dry wood fiber mass). Following that, a 20% peat-in-water slurry was fed into the sizing box. The peat used had an initial moisture content of 25% and was taken in the amount of 2.0% (based on the absolutely dry wood fiber mass). The peat slurry was forced through a screen filter as a preliminary step. In the pulp line upstream of the head box, the wood pulp slurry was diluted to a concentration of 1.8 mass %, with the pH value equal to 5.0. Upon casting the wood pulp slurry over the wire screen, the fibrous mat obtained as a result was passed between the rolls of three fore presses, with the daylights equal to 14-15 mm, 13-14 mm, and 12-13 mm, respectively.
Fiberboard pressing was carried out at a pressure of 5.5 MPa, with the daylights equal to 10-13 mm in the first press, 10-11 mm in the second, and 8-9 mm in the third. The pressing temperature was 190° C. After heat treating the fiberboards for a period of 2 hours at a temperature of 168° C. and moistening them with water having a temperature of 50° C. to obtain a moisture content of 10%, the fiberboards exhibited physical properties as shown in Table 3.
EXAMPLE 2
Using the conditions of Example 1, fiberboards were prepared, with the additives including 6% of peat (based on the absolutely dry wood fiber mass), phenol-formaldehyde resin taken in the amount of 2% (based on the absolutely dry wood fiber mass), and 2% of carbamide (based on the absolutely dry wood fiber mass). The initial moisture content of peat was 35%. Fiberboard heat treatment time was 2 hours. The physical properties of the fiberboards were as shown in Table 3.
EXAMPLE 3
Using the conditions as described in Example 1, fiberboards were prepared, with the additives used including peat taken in the amount of 15% (based on the absolutely dry wood fiber mass). The peat had an initial moisture content of 40%. The quantity of phenol-formaldehyde resin used as binder was 2% (based on the absolutely dry wood fiber mass). Carbamide was taken in the amount of 18% (based on the absolutely dry wood fiber mass). Fiberboard heat treatment time was 2 hours. The physical properties were as shown in Table 3.
EXAMPLE 4
Using the conditions as described in Example 1, fiberboards were prepared incorporating peat as an additive in the amount of 30% (based on the absolutely dry wood fiber mass). The initial moisture content of the peat was 60%. The quantity of carbamide used was 1% (based on the absolutely dry wood fiber mass). The binder quantity was 3% (based on the absolutely dry wood fiber mass). Fiberboard heat treatment time was 2.5 hours. The physical properties of the fiberboards thus obtained were as shown in Table 3.
EXAMPLE 5
Using the conditions as described in Example 1, fiberboards were fabricated incorporating peat as an additive taken in the amount of 45%. The initial moisture content of the peat used was 50%. The amount of phenol-formaldehyde resin incorporated in the slurry was 8% (based on the absolutely dry wood fiber mass). The carbamide quantity was 0.2% (based on the absolutely dry wood fiber mass). Fiberboard heat treatment time was 1.2 hours. The physical properties of the fiberboards obtained were as shown in Table 3.
EXAMPLE 6
Using the conditions as described in Example 1, fiberboards were prepared incorporating as an additive peat having a moisture content of 70%. The amount of peat used was 50% (based on the absolutely dry wood fiber mass). The binder quantity was 10% (based on the absolutely dry wood fiber mass). Fiberboard heat treatment time was 1.5 hours. Carbamide was not used in this example of fiberboard fabrication. The physical properties of the fiberboards obtained were as shown in Table 3.
EXAMPLE 7 (FOR COMPARISON)
Using the conditions as described in Example 1, fiberboards were fabricated incorporating 2% of phenol-formaldehyde resin (based on the absolutely dry wood fiber mass). No use was made of peat or carbamide. Fiberboard heat treatment time was 4.0 hours. The physical properties were as shown in Table 3.
As may be seen from the foregoing information and the data cited in Table 3, the use of the proposed method yields fiberboards featuring high physical properties, such as water absorption, strength, and swelling in water.
Replacement in part of expensive wood with peat not only makes it possible to cut down the capital costs involved in fiberboard fabrication, but also to reduce to a considerable extent environmental pollution owing to a reduced concentration of phenol and formaldehyde in the waste waters and in the air. The use of carbamide-modified peat enables higher production efficiency and lower energy costs on account of less time consumed at the heat treatment stage.
TABLE 3__________________________________________________________________________Quantity of components Ratiostaken for experimenta- carbamide peat to Fiberboardtion, % by mass moisture to phenol- phenol- Fiber- ultimateSl formaldehyde carb- content of formaldehyde formaldehyde board strength,No. peat resin amide peat, % resin resin mm MPa1 2 3 4 5 6 7 8 9__________________________________________________________________________1 2.0 2.0 2.0 25.0 1:1 1:1 3.1 41.02 6.0 2.0 2.0 35.0 1:1 3:1 3.0 42.03 15.0 2.0 1.8 40.0 0.9:1 7:1 3.2 42.24 30.0 3.0 1.0 60.0 1:3 10:1 3.2 42.05 45.0 8.0 0.2 50.0 0.02:1 5.6:1 3.1 42.56 50.0 10.0 -- 70.0 -- 5:1 3.0 42.37 -- 2.0 -- -- -- -- 3.1 40.8__________________________________________________________________________Fiberboardwater Fiberboard Fiberboardabsorption, % swelling, % Fiberboard heat Concentration in Emission,(for (for 24 density, treatment waste waters, mg/l mg/m.sup.3Sl 24 hours) hours) kg/m.sup.3 time, hours formaldehyde phenol formaldehyde phenolNo. 10 11 12 13 14 15 16 17__________________________________________________________________________1 20.4 15.0 892 2.0 10.0 12.0 0.001 0.0042 20.6 15.0 872 2.0 6.8 8.0 0.001 0.0043 22.8 18.2 862 2.0 4.3 6.5 -- 0.0024 23.6 18.4 860 2.5 0.7 3.0 0.001 0.0035 24.2 19.1 865 1.2 0.7 2.0 0.01 0.0016 25.0 19.3 867 1.5 0.5 2.0 0.01 0.0017 21.4 14.9 870 4.0 25.0 17.0 0.01 0.01__________________________________________________________________________
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Disclosed in accordance with the invention is a method for fiberboard manufacture comprising the steps of steaming and grinding woodchips to obtain a wood pulp, using said wood pulp to prepare a slurry of wood pulp in water, mixing said slurry with a binder, a cure catalyst for the binder, a water-repellent additive, peat, and carbamide to obtain a mixture, casting said mixture and dewatering said mixture to obtain a mat, and compacting said mat to obtain fiberboard which is subjected to heat treatment, in which method the peat used has a moisture content of between 25 and 70 percent and the peat content in said mixture is between 2.5 and 50 percent by mass, with the ratio of absolutely dry peat to said binder equal to between 1.0-7:1.0, respectively, while the carbamide content in said mixture is between 0.2 and 2.0 percent by mass, with the ratio of said carbamide to said binder equal to between 0.02-1:1, respectively.
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[0001] This application is a continuation of U.S. application Ser. No. 12/611,510, filed Nov. 3, 2009, which is a continuation of U.S. application Ser. No. 10/715,055, filed Nov. 17, 2003, now U.S. Pat. No. 7,671,070, which is a continuation of U.S. application Ser. No. 10/200,868, filed Jul. 22, 2002, now U.S. Pat. No. 6,716,830, which is a continuation of U.S. patent application Ser. No. 09/646,797, filed Sep. 22, 2000, now abandoned, which is the National Stage of International Application No. PCT/US99/22622, filed Sep. 29, 1999, which claims benefit under 35 U.S.C. §119(e) of U.S. Provisional Application Nos. 60/102,504 and 60/102,506, filed on Sep. 30, 1998.
BACKGROUND OF THE INVENTION
[0002] The present invention is directed to the provision of topical antibiotic pharmaceutical compositions for the treatment of ophthalmic, otic and nasal infections, particularly bacterial infections, and to methods of treating ophthalmic, otic and nasal infections by applying those compositions to the affected tissues. The compositions and methods of the invention are based on the use of a new class of antibiotics. The compositions of the present invention may also contain one or more anti-inflammatory agents.
[0003] The use of quinolone antibiotics to treat infections represents the current state of the art in the field of ophthalmic pharmaceutical compositions and methods of treatment. For example, a topical ophthalmic composition containing the quinolone ciprofloxacin is marketed by Alcon Laboratories, Inc. under the name CILOXAN™ (Ciprofloxacin 0.3%) Ophthalmic Solution. The following quinolones have also been utilized in ophthalmic antibiotic compositions:
[0000]
Quinolone
Product
Manufacturer
Ofloxacin
OCUFLOX ™
Allergan
Norfloxacin
CHIBROXIN ™
Merck
Lomefloxacin
LOMEFLOX ™
Senju
[0004] The foregoing quinolone antibiotic compositions are generally effective in treating ophthalmic infections, and have distinct advantages over prior ophthalmic antibiotic compositions, particularly those having relatively limited spectrums of antimicrobial activity, such as: neomycin, polymyxin B, gentamicin and tobramycin, which are primarily useful against gram negative pathogens; and bacitracin, gramicidin, and erythromycin, which are primarily active against gram positive pathogens. However, despite the general efficacy of the ophthalmic quinolone therapies currently available, there is a need for improved compositions and methods of treatment based on the use of antibiotics that are more effective than existing antibiotics against key ophthalmic pathogens, and less prone to the development of resistance by those pathogens.
[0005] There is an even greater need for effective topical compositions and methods for treating otic and nasal infections, particularly bacterial infections. The use of oral antibiotics to treat otic infections in children has limited efficacy, and creates a serious risk of pathogen resistance to the orally administered antibiotics.
[0006] Ophthalmic, otic and nasal infections are frequently accompanied by inflammation of the infected ophthalmic, otic and nasal tissues and perhaps even surrounding tissues. Similarly, ophthalmic, otic and nasal surgical procedures that create a risk of microbial infections frequently also cause inflammation of the affected tissues. Thus, there is also a need for ophthalmic, otic and nasal pharmaceutical compositions that combine the anti-infective activity of one or more antibiotics with the anti-inflammatory activity of one or more steroid or non-steroid agents in a single composition.
SUMMARY OF THE INVENTION
[0007] The invention is based on the use of a potent new class of antibiotics to treat ophthalmic, otic and nasal infections, as well as the prophylactic use of these antibiotics following surgery or other trauma to ophthalmic, otic or nasal tissues. The compositions of the present invention may also be administered to the affected tissues during ophthalmic, otic or nasal surgical procedures to prevent or alleviate post-surgical infection.
[0008] The compositions preferably also contain one or more anti-inflammatory agents to treat inflammation associated with infections of ophthalmic, otic or nasal tissues. The anti-inflammatory component of the compositions is also useful in treating inflammation associated with physical trauma to ophthalmic, otic or nasal tissues, including inflammation resulting from surgical procedures. The compositions of the present invention are therefore particularly useful in treating inflammation associated with trauma to ophthalmic, otic or nasal tissues wherein there is either an infection or a risk of an infection resulting from the trauma.
[0009] Examples of ophthalmic conditions that may be treated with the compositions of the present invention include conjunctivitis, keratitis, blepharitis, dacyrocystitis, hordeolum and corneal ulcers. The compositions of the invention may also be used prophylactically in connection with various ophthalmic surgical procedures that create a risk of infection.
[0010] Examples of otic conditions that may be treated with the compositions of the present invention include otitis externa and otitis media. With respect to the treatment of otitis media, the compositions of the present invention are primarily useful in cases where the tympanic membrane has ruptured or tympanostomy tubes have been implanted. The compositions may also be used to treat infections associated with otic surgical procedures, such as tympanostomy, or to prevent such infections.
[0011] The compositions of the present invention are specially formulated for topical application to ophthalmic, otic and nasal tissues. The compositions are preferably sterile, and have physical properties (e.g., osmolality and pH) that are specially suited for application to ophthalmic, otic and nasal tissues, including tissues that have been compromised as the result of preexisting disease, trauma, surgery or other physical conditions.
DETAILED DESCRIPTION OF THE INVENTION
[0012] The antibiotics used in the compositions and methods of the present invention have the following formula:
[0000]
[0013] wherein:
[0014] A is CH, CF, CCl, C—OCH 3 , or N;
X 1 is H, halogen, NH 2 , or CH 3 ;
[0016] R 1 is C 1 to C 3 alkyl, FCH 2 CH 2 , cyclopropyl or phenyl, optionally mono-, di- or tri-substituted by halogen, or A and R 1 together can form a bridge of formula C—O—CH 2 —CH(CH 3 );
[0017] R 2 is H, C 1 to C 3 alkyl (optionally substituted by OH, halogen or NH 2 ), or 5-methyl-2-oxo-1,3-dioxol-4-yl-methyl; and
[0018] B is a selected from the group consisting of:
[0000]
[0019] wherein:
[0020] Y is O or CH 2 ;
[0021] R 3 is C 2 -C 5 alkoxyl, CH 2 —CO—C 6 H 5 , CH 2 CH 2 CO 2 R′, R′O 2 C—CH═C—CO 2 R′, CH═CH—CO 2 R′ or CH 2 CH 2 —CN,
[0022] wherein:
[0023] R′ is H or C 1 to C 3 alkyl;
[0024] R 4 is H, C 1 to C 3 alkyl, C 2 -C 5 alkoxyl, CH 2 —CO—C 6 H 5 , CH 2 CH 2 CO 2 R′, R′O 2 C—CH═C—CO 2 R′, CH═CH—CO 2 R′, CH 2 CH2—CN or 5-methyl-2-oxo-1,3-dioxol-4-yl-methyl,
[0025] wherein:
[0026] R′ is H or C 1 to C 3 alkyl; and
[0027] their pharmaceutically useful hydrates and salts.
[0028] The compound Moxifloxacin is most preferred. Moxifloxacin has the following structure:
[0000]
[0029] Further details regarding the structure, preparation, and physical properties of Moxifloxacin and other compounds of formula (I) are provided in U.S. Pat. No. 5,607,942.
[0030] The concentrations of the antibiotics of formula (I) in the compositions of the present invention will vary depending on the intended use of the compositions (e.g., treatment of existing infections or prevention of post-surgical infections), and the relative antimicrobial activity of the specific antibiotic selected. The antimicrobial activity of antibiotics is generally expressed as the minimum concentration required to inhibit the growth of a specified pathogen. This concentration is also referred to as the “minimum inhibitory concentration” or “MIC”. The term “MIC90” refers to the minimum concentration of antibiotic required to inhibit the growth of ninety percent (90%) of the strains of a species. The concentration of an antibiotic required to totally kill a specified bacteria is referred to as the “minimum bactericidal concentration” or “MBC”. The minimum inhibitory concentration of Moxifloxacin for several bacteria commonly associated with ophthalmic, otic and nasal infections are provided in the following table:
[0000]
Microorganism
MIC 90
S. aureus /methicillin sensitive
0.13
S. aureus /methicillin resistant
4.0
S. aureus /quinolone resistant
4.0
S. epidermidis /methicillin sensitive
0.25
S. epidermidis /methicillin resistant
4.0
S. pneumoniae /penicillin sensitive
0.25
S. pneumoniae /penicillin resistant
0.25
P. aeruginosa
8.0
H. influenzae /β-lactamase positive
0.06
H influenzae /β-lactamase negative
0.06
[0031] All of the foregoing concentrations are expressed as micrograms per milliliter (“mcg/ml”).
[0032] The appropriate antibiotic concentration for ophthalmic compositions will generally be an amount of one or more antibiotics of formula (I) sufficient to provide a concentration in the aqueous humor and lacrimal fluid of the eye equal to or greater than the MIC90 level for the selected antibiotic(s), relative to gram-negative and gram-positive organisms commonly associated with ophthalmic infections. The appropriate concentration for otic and nasal compositions will generally be an amount of one or more antibiotics of formula (I) sufficient to provide a concentration in the infected tissues equal to or greater than the MIC90 level for the selected antibiotic(s), relative to gram-negative and gram-positive organisms commonly associated with otic or nasal infections. Such amounts are referred to herein as “an antimicrobial effective amount”. The compositions of the present invention will typically contain one or more compounds of formula (I) in a concentration of from about 0.1 to about 1.0 percent by weight (“wt. %”) of the compositions.
[0033] The compositions of the present invention may also contain one or more anti-inflammatory agents. The anti-inflammatory agents utilized in the present invention are broadly classified as steroidal or non-steroidal. The preferred steroidal anti-inflammatory agents are glucocorticoids.
[0034] The preferred glucocorticoids for ophthalmic and otic use include dexamethasone, loteprednol, rimexolone, prednisolone, fluorometholone, and hydrocortisone. The preferred glucocorticoids for nasal use include mometasone, fluticasone, beclomethasone, flunisolide, triamcinolone and budesonide.
[0035] The dexamethasone derivatives described in U.S. Pat. No. 5,223,493 (Boltralik) are also preferred steroidal anti-inflammatory agents, particularly with respect to compositions for treating ophthalmic inflammation. The following compounds are especially preferred:
[0000]
[0036] These compounds are referred to herein as “21-ether derivatives of dexamethasone”. The 21-benzyl ether derivative (i.e., compound AL-2512) is particularly preferred.
[0037] The preferred non-steroidal anti-inflammatory agents are: prostaglandin H synthetase inhibitors (Cox I or Cox II), also referred to as cyclooxygenase type I and type II inhibitors, such as diclofenac, flurbiprofen, ketorolac, suprofen, nepafenac, amfenac, indomethacin, naproxen, ibuprofen, bromfenac, ketoprofen, meclofenamate, piroxicam, sulindac, mefanamic acid, diflusinal, oxaprozin, tolmetin, fenoprofen, benoxaprofen, nabumetome, etodolac, phenylbutazone, aspirin, oxyphenbutazone, NCX-4016, HCT-1026, NCX-284, NCX-456, tenoxicam and carprofen; cyclooxygenase type II selective inhibitors, such as NS-398, vioxx, celecoxib, P54, etodolac, L-804600 and S-33516; PAF antagonists, such as SR-27417, A-137491, ABT-299, apafant, bepafant, minopafant, E-6123, BN-50727, nupafant and modipafant; PDE IV inhibitors, such as ariflo, torbafylline, rolipram, filaminast, piclamilast, cipamfylline, CG-1088, V-11294A, CT-2820, PD-168787, CP-293121, DWP-205297, CP-220629, SH-636, BAY-19-8004, and roflumilast; inhibitors of cytokine production, such as inhibitors of the NFkB transcription factor; or other anti-inflammatory agents known to those skilled in the art.
[0038] The concentrations of the anti-inflammatory agents contained in the compositions of the present invention will vary based on the agent or agents selected and the type of inflammation being treated. The concentrations will be sufficient to reduce inflammation in the targeted ophthalmic, otic or nasal tissues following topical application of the compositions to those tissues. Such an amount is referred to herein as “an anti-inflammatory effective amount.” The compositions of the present invention will typically contain one or more anti-inflammatory agents in an amount of from about 0.01 to about 1.0 wt. %.
[0039] The compositions are typically administered to the affected ophthalmic, otic or nasal tissues by topically applying one to four drops of a sterile solution or suspension, or a comparable amount of an ointment, gel or other solid or semisolid composition, one to four times per day. However, the compositions may also be formulated as irrigating solutions that are applied to the affected ophthalmic, otic or nasal tissues during surgical procedures.
[0040] The ophthalmic, otic and nasal compositions of the present invention will contain one or more compounds of formula (I) and preferably one or more anti-inflammatory agents, in pharmaceutically acceptable vehicles. The compositions will typically have a pH in the range of 4.5 to 8.0. The ophthalmic compositions must also be formulated to have osmotic values that are compatible with the aqueous humor of the eye and ophthalmic tissues. Such osmotic values will generally be in the range of from about 200 to about 400 milliosmoles per kilogram of water (“mOsm/kg”), but will preferably be about 300 mOsm/kg.
[0041] Ophthalmic, otic and nasal pharmaceutical products are typically packaged in multidose form. Preservatives are thus required to prevent microbial contamination during use. Suitable preservatives include: polyquatemium-1, benzalkonium chloride, thimerosal, chlorobutanol, methyl paraben, propyl paraben, phenylethyl alcohol, edetate disodium, sorbic acid, or other agents known to those skilled in the art. The use of polyquatemium-1 as the antimicrobial preservative is preferred. Typically such preservatives are employed at a level of from 0.001% to 1.0% by weight.
[0042] The solubility of the components of the present compositions may be enhanced by a surfactant or other appropriate co-solvent in the composition. Such co-solvents include polysorbate 20, 60, and 80, polyoxyethylene/polyoxypropylene surfactants (e.g., Pluronic F-68, F-84 and P-103), cyclodextrin, or other agents known to those skilled in the art. Typically such co-solvents are employed at a level of from 0.01% to 2% by weight.
[0043] The use of viscosity enhancing agents to provide the compositions of the invention with viscosities greater than the viscosity of simple aqueous solutions may be desirable to increase ocular absorption of the active compounds by the target tissues or increase the retention time in the eye, ear or nose. Such viscosity building agents include, for example, polyvinyl alcohol, polyvinyl pyrrolidone, methyl cellulose, hydroxy propyl methylcellulose, hydroxyethyl cellulose, carboxymethyl cellulose, hydroxy propyl cellulose or other agents know to those skilled in the art. Such agents are typically employed at a level of from 0.01% to 2% by weight.
[0044] The following examples are provided to further illustrate the ophthalmic, otic and nasal compositions of the present invention.
EXAMPLE 1
Ophthalmic/Otic/Nasal Solution
[0045]
[0000]
Ingredient
Amount (wt. %)
Moxifloxacin
0.35
Sodium Acetate
0.03
Acetic Acid
0.04
Mannitol
4.60
EDTA
0.05
Benzalkonium Chloride
0.006
Water
q.s.100
EXAMPLE 2
Ophthalmic/Otic/Nasal Suspension
[0046]
[0000]
Ingredient
Amount (wt. %)
Moxifloxacin
0.3
Dexamethasone, Micronized USP
0.10
Benzalkonium Chloride
0.01
Edetate Disodium, USP
0.01
Sodium Chloride, USP
0.3
Sodium Sulfate, USP
1.2
Tyloxapol, USP
0.05
Hydroxyethylcellulose
0.25
Sulfuric Acid and/or Sodium Hydroxide,
q.s. for pH adjustment to 5.5
NF
Purified Water, USP
q.s. to 100
EXAMPLE 3
Ophthalmic Ointment
[0047]
[0000]
Ingredient Amount
(wt. %)
Moxifloxacin
0.35
Mineral Oil, USP
2.0
White petrolatium, USP
q.s 100
EXAMPLE 4
Ophthalmic Ointment
[0048]
[0000]
Ingredient
Amount (wt. %)
Moxifloxacin
0.3
Fluorometholone Acetate, USP
0.1
Chlorobutanol, Anhydrous, NF
0.5
Mineral Oil, USP
5
White Petrolatum, USP
q.s. 100
[0049] The invention has been described herein by reference to certain preferred embodiments. However, as obvious variations thereon will become apparent to those skilled in the art, the invention is not to be considered as limited thereto.
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Ophthalmic, otic and nasal compositions containing a new class of antibiotics (e.g., moxifloxacin) are disclosed. The compositions preferably also contain one or more anti-inflammatory agents. The compositions may be utilized to treat ophthalmic, otic and nasal conditions by topically applying the compositions to the affected tissues.
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CROSS REFERENCE TO RELATED APPLICATIONS
This application is a continuation of PCT NO. PCT/CN2015/085719 filed Jul. 31, 2015, which claims priority to CN 201410455826.7 filed Sep. 9, 2014, both of which are incorporated by reference.
TECHNICAL FIELD
The present invention relates to the organic synthetic route design and the technical field for APIs and intermediates preparation, especially relating to the preparation method of Nintedaib for the treatment of idiopathic pulmonary fibrosis.
BACKGROUND
Nintedanib developed by Boehringer Ingelheim is a kind of oral triple angiokinase inhibitor which can simultaneously block three growth factor receptors: the endothelial growth factor receptor, the platelet-derived growth factor receptor and the fibroblast growth factor receptor. The blockade of these receptors may lead to inhibition of angiogenesis, which plays a key role in inhibiting tumor growth. The drug used for the treatment of idiopathic pulmonary fibrosis was granted the title of “breakthrough therapy drug” by U.S. FDA for the first time in July 2014, and the trade name of its ethane sulfonate preparation is Vargatef.
The chemical name of Nintedanib: (Z)-{1-[4-(N-((4-methyl-piperazin-1-yl)-methylcarbonyl)-N-methyl-amino) phenylamino]-1-phenyl-methyl}-2-oxo-2,3-dihydro-1H-indole-6-carboxylate (I); the structural formula as follows:
The preparation method of Nintedanib has been reported, and the synthesis method of Nintedanib and its analogue has been reported in PCT patents WO2001027081 and WO2009071523 from the original company. In this method, the drug is generated through condensation reaction of two key intermediates A and B under the alkaline condition.
Additionally, the synthesis method of intermediates A and B are further reported in the literature J. Med. Chem, Pages 4466-4480, Vol. 52, 2009 and Chinese Journal of Pharmaceuticals, Pages 726-729, Vol. 43, Issue 9, 2012. And based on the optimized reaction condition, reaction sequence, rate of charge and catalyst selection, the synthetic route stated above becomes more simple and reasonable.
By analyzing the structural characteristics of Nintedanib and combination of the current synthesis method of this compound and its intermediates, the applicant finds cis “methylene on indoline ring” structure and its formation method is the key to the whole synthesis process. It is also one of the difficulties. The process from the original company is that through the 3-position substitution and condensation reactions on 2-oxo-indoline ring and trimethyl orthobenzoate under the action of acetic anhydride, the trans “methylene” derivative, namely intermediate A is obtained. The methoxy in intermediate A is used as the leaving group to get a substitution reaction with the anilino in intermediate B, thus generating the target product. The intramolecular hydrogen bond in intermediate A can promote the transformation from “trans” to “cis”.
However, there exist some flaws or weaknesses in the existing process route. For example, the alkylation on the benzene ring easily produces positional isomer due to the impacts from nitryl. The especial case is that the 2-oxo-indoline ring after ring formation must be protected by acylation to achieve the smooth condensation reaction in which methylene is produced. The removal of acylation Pg will affect the functional groups of the other amide in the product, leading to the increased side reactions to reduce yield and quality.
In view of the flaws in the existing process, the development of economical and environmentally friendly preparation technique with simple process can greatly promote the industrial production of the API and improve its economic and social benefits, and in this technique, the seeking for the synthetic route without protection and with deprotection is especially important.
SUMMARY OF THE INVENTION
The present invention aims to provide a preparation method of Nintedanib. The preparation method has an easily obtained raw material and a simple process, is economical and environmentally friendly, and is suitable for industrial production.
To achieve the above object of the present invention, the following technical scheme is mainly adopted in the present invention: a preparation method of Nintedanib (I),
comprising the following steps: carrying out a condensation reaction on 4-(R acetate-2-yl)-3-nitrobenzoate (II) and trimethyl orthobenzoate to obtain (E)-4-[(2-methoxybenzylidene) R acetate-2-yl]-3-nitrobenzoate (III); carrying out a substitution reaction on the compound (EI) and N-(4-aminophenyl)-N-methyl-2-(4-methyl piperazine-1-yl) acetamide (IV) under the action of an acid-binding agent to generate (Z)-4-{[2-(N-methyl-2-(4-methyl piperazine-1-yl) acetamido-aniline) benzylidene] R acetate-2-yl}-3-nitrobenzoate (V); and sequentially carrying out reduction reactions and cyc-lization reactions on the compound (V) to prepare the Nintedanib (I). Wherein, R in said 4-(R acetate-2-yl)-3-nitrobenzoate (II) is methyl, ethyl, aliphatic group with 1 to 10 carbon atoms, phenyl or benzyl, but methyl or ethyl for the optimization case.
In addition, the following attached technical scheme is included in the present invention:
The molar ratio of raw material 4-(R acetate-2-yl)-3-nitrobenzoate (II) and trimethyl orthobenzoate for said condensation reaction is 1:1˜10, but 1:2˜6 for the optimization case.
The solvent used in said condensation reaction is acetic anhydride.
The temperature for said condensation reaction is 110˜130° C.
The molar ratio of raw material (E)-4-[(2-methoxybenzylidene) R acetate-2-yl]-3-nitrobenzoate (III) and N-(4-aminophenyl)-N-methyl-2-(4-methyl piperazine-1-yl) acetamide (IV) for said substitution reaction is 1:0.5-1.5, but 1:1˜1.2 for the optimization case.
The solvents used in said substitution reaction are N,N-dimethylformamide, N,N-dimethylacetamide, dioxane, dimethylsulfoxide, methylbenzene or dimethylbenzen, but N,N-dimethylformamide or dioxane for the optimization case.
The acid-binding agents used in said substitution reaction are triethylamine, pyridine, 4-methylmorpholine, diisopropylethylamine, 4-dimethylaminopyridine, potassium carbonate, lithium carbonate or potassium tert-butoxide, but pyridine, lithium carbonate or diisopropylethylamine for the optimization case.
The temperature for said substitution reaction is 50˜100° C., but 80˜90° C. for the optimization case.
The reductive agents used in said reduction reaction are iron powder, tin powder, zinc powder, aluminite powder, rongalite, hydrazine hydrate, stannous chloride, sodium sulphide or hydrogen, but iron powder, zinc powder or hydrogen for the optimization case.
The acid catalysts added for said metal reduction are hydrochloric acid, phosphoric acid, acetic acid or acetic anhydride, but anhydride for the optimization case.
If the hydrogen is used as the reductive agent in said reduction reaction, the catalysts used are palladium carbon, platinum carbon, palladium hydroxide or raney nickel, but palladium carbon or platinum carbon for the optimization case.
The solvents used in said catalytic hydrogenation are methyl alcohol, ethyl alcohol, propyl alcohol or isopropyl alcohol, but ethyl alcohol or isopropyl alcohol for the optimization case.
The temperature for said cyclization reaction is 50˜150° C., but 110˜120° C. for the optimization case.
The solvents used in said cyclization reaction are benzene, methylbenzene, dimethylbenzene, acetic acid, acetic anhydride or dioxane, but methylbenzene, acetic acid or acetic anhydride for the optimization case.
The product from said reduction reaction needs no post-processing, and can be directly used for the cyclization reaction.
Compared with the existing technology, the preparation method of Nintedanib (I) in the present invention has an easily obtained raw material and a simple process and is economical and environmentally friendly, which is beneficial to the industrial production of the API consequently to promote the development of economy and technology.
DETAILED DESCRIPTION
The unrestricted detailed description for the technical scheme of the present invention is further given, based on the following several preferred embodiments. The preparation method of raw material 4-(R acetate-2-yl)-3-nitrobenzoate (II) and N-(4-aminophenyl)-N-methyl-2-(4-methyl piperazine-1-yl) acetamide (IV) can be referred to J. Med. Chem, Pages 4466-4480, Vol. 52, 2009 and Chinese Journal of Pharmaceuticals , Pages 726-729, Vol. 43, Issue 9, 2012 where the preparation method of the same compounds are introduced.
Embodiment 1
Add 4-(methyl acetate-2-yl)-3-nitrobenzoate (II) (2.53 g, 10 mmol), trimethyl orthobenzoate (9.10 g, 50 mmol) and 30 mL acetic anhydride into the reaction bottle, and get it heated to reflux status with the reaction of 6˜8 hours. After that, the end of the reaction is found by TLC detection.
When it cools down to the room temperature, there is separated solid. The crude generated product is recrystallized through normal hexane and ethyl acetate (1:1, V/V) and dried in the air to get 2.65 g off-white solid (E)-4-[(2-methoxybenzylidene) methyl acetate-2-yl]-3-nitrobenzoate (III) with 71.4% yield.
Melting point is 172-474° C. and mass spectrum (EI) is m/z 372 (M+H).
Embodiment 2
Add 4-(benzyl acetate-2-yl)-3-nitrobenzoate (II) (3.29 g, 10 mmol), trimethyl orthobenzoate (5.46 g, 30 mmol) and 40 mL acetic anhydride into the reaction bottle, and get it heated to reflux status with the reaction of 8 hours. After that, the end of the reaction is found by TLC detection. When it cools down to the room temperature, there is separated solid. The crude generated product is recrystallized through normal hexane and ethyl acetate (1:2, V/V) and dried in the air to get 3.35 g off-white solid (E)-4-[(2-methoxybenzylidene) benzyl acetate-2-yl]-3-nitrobenzoate (Ill) with 74.9% yield. Melting point is 205-209° C. and mass spectrum (EI) is m/z 448 (M+H).
Embodiment 3
Add (E)-4-[(2-methoxybenzylidene) methyl acetate-2-yl]-3-nitrobenzoate (III) (3.71 g, 10 mmol), N-(4-aminophenyl)-N-methyl-2-(4-methyl piperazine-1-yl) acetamide (IV) (2.88 g, 11 mmol) and 50 mL N,N-dimethylformamide into the reaction bottle and get it heated to 80˜85° C., and then stir it with the reaction of 2 hours. When it cools down to the room temperature, the acid-binding agent pyridine (5 mL) is added with the stirring of 2 hours at the room temperature. Pour the reaction liquid into 150 mL water, and produce the separated solid. Said separated solid is filtered, and the crude product from filtration is recrystallized through ethyl alcohol to get 4.32 g yellow solid (Z)-4-{[2-(N-methyl-2-(4-methyl piperazine-1-yl) acetamido-aniline) benzylidene] methyl acetate-2-yl}-3-nitrobenzoate (V) with 71.9% yield. Melting point is 185˜188° C. and mass spectrum (EI) is m/z 602 (M+H).
Embodiment 4
Add (E)-4-[(2-methoxybenzylidene) benzyl acetate-2-yl]-3-nitrobenzoate (III) (4.47 g, 10 mmol), N-(4-aminophenyl)-N-methyl-2-(4-methyl piperazine-1-yl) acetamide (IV) (2.88 g, 11 mmol) and 50 mL dioxane into the reaction bottle and get it heated to 80˜85° C., and then stir it with the reaction of 2.5 hours. When it cools down to the room temperature, the acid-binding agent lithium carbonate (1.1 g) is added with the stirring of 3 hours at the room temperature. Pour the reaction liquid into 150 mL water, and produce the separated solid. Said separated solid is filtered, and the crude product from filtration is recrystallized through methyl alcohol to get 4.93 g light yellow solid (Z)-4-{[2-(N-methyl-2-(4-methyl piperazine-1-yl) acetamido-aniline) benzylidene] benzyl acetate-2-yl}-3-nitrobenzoate (V) with 73.9% yield. Melting point is 222˜224° C. and mass spectrum (EI) is m/z 678 (M+H).
Embodiment 5
Add (Z)-4-{[2-(N-methyl-2-(4-methyl piperazine-1-yl) acetamido-aniline) benzylidene] methyl acetate-2-yl}-3-nitrobenzoate (V) (3.0 g, 5 mmol), 10% palladium carbon (0.3 g, 10% w/w) and 25 mL isopropyl alcohol into the hydrogenation reactor, and based on the hydrogenation operating procedures, the following actions are taken: add hydrogen at the room temperature and under the pressure of 5-8 Kg/cm 2 ; then stir it with the reaction of 4 hours until no hydrogen is consumed. After filtration, the catalyst palladium carbon is recovered, the filtrate undergoing a condensation process through reducing the pressure, and then the residue is dissolved through methylbenzene. Under the increased temperature of 115˜120° C., the reaction lasts 5 hours. After that, the end of the reaction is found by HPLC detection. Methylbenzene is recovered through reducing the pressure, and the residue is recrystallized through methyl alcohol to get 2.37 g yellow solid Nintedanib (I) with 87.9% yield. Melting point is 241-243° C. and mass spectrum (EI) is: m/z 540 (M+H), 1 H NMR (DMSO d 6 ): 2.27 (s, 3H), 2.43 (111, 8H), 2.78 (s, 2H), 3.15 (s, 3H), 3.82 (s, 3H), 5.97 (d, J=8.3 Hz, 1H), 6.77 (d, J=8.7 Hz, 1H), 6.96 (d, J=8.6 Hz, 2H), 7.32-7.62 (m, 8H), 8.15 (s, 1H), 12.15 (s, 1H).
Embodiment 6
Add (Z)-4-{[2-(N-methyl-2-(4-methyl piperazine-1-yl) acetamido-aniline) benzylidene] benzyl acetate-2-yl}-3-nitrobenzoate (V) (3.4 g, 5 mmol) and 50 mL acetic anhydride into the reaction bottle, and iron powder (0.85 g, 15 mmol) is added in batches. The reaction lasts 4 hours at the increased temperature of 55˜60° C. The following processes are cooling down and filtration, and then the filtrate is heated to 110˜115° C. with the reaction of 5-6 hours. After that, the end of the reaction is found by HPLC detection. After condensation through reducing the pressure, the residue is recrystallized through methylbenzene to get 2.30 g yellow solid Nintedanib (I) with 85.3% yield. Melting point is 241˜243° C. and mass spectrum (EI) is: m/z 540 (M+H), 1 H NMR (DMSO d 6 ): 2.27 (s, 3H), 2.43 (m, 8H), 2.78 (s, 2H), 3.15 (s, 3H), 3.82 (s, 3H), 5.97 (d, J=8.3 Hz, 1H), 6.77 (d, J==8.7 Hz, 1H), 6.96 (d, J=8.6 Hz, 2H), 7.32-7.62 (m, 8H), 8.15 (s, 1H), 12.15 (s, 1H).
It should be pointed out that the embodiments mentioned above are used to only describe the technical designs and features of the present invention rather than limit the scope of protection of the present invention, because the aim is to make the persons familiar with this technology learn the contents of the present invention and then conduct implementation according to these embodiments. Any equivalent changes or modifications made according to the spirit and principles of the present invention will be included in the protection scope of the present invention.
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Disclosed is a preparation method of nintedanib (I), comprising the following steps: carrying out a condensation reaction on 4-(R acetate-2-yl)-3-nitrobenzoate (II) and trimethyl orthobenzoate to obtain (E)-4-[(2-methoxybenzylidene) R acetate-2-yl]-3-nitrobenzoate (III); carrying out a substitution reaction on the compound (EI) and N-(4-aminophenyl)-N-methyl-2-(4-methyl piperazine-1-yl) acetamide (IV) under the action of an acid-binding agent to generate (Z)-4-{[2-(N-methyl-2-(4-methyl piperazine-1-yl) acetamido-aniline) benzylidene] R acetate-2-yl}-3-nitrobenzoate (V); and sequentially carrying out reduction reactions and cyc-lization reactions on the compound (V) to prepare the nintedanib (I). The preparation method has an easily obtained raw material and a simple process, is economical and environmentally friendly, and is suitable for industrial production.
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CROSS-REFERENCE TO RELATED APPLICATION
[0001] The present application claims the benefit of U.S. Provisional Application No. 61/182,225, filed May 29, 2009, which is incorporated herein by reference.
FIELD
[0002] The present application concerns a folding knife, and more specifically, a locking mechanism for a folding knife.
BACKGROUND
[0003] Various types of folding knives having push buttons for unlocking a blade from a locked position are known. Such knives typically are complicated and require a relatively large number of parts. One example is disclosed in U.S. Pat. No. 4,148,140, which discloses a ball latch mechanism that can lock the blade in one of several positions. What is needed is a much simpler locking mechanism for a folding knife having a push button or similar mechanism for disengaging the locking mechanism.
SUMMARY
[0004] The present disclosure concerns embodiments of a folding knife having a locking mechanism for locking a blade in open and/or closed positions. The locking mechanism comprises a first locking element on the blade and a corresponding second locking element on the handle that is adapted to engage the first locking element when the blade is in open and/or closed positions. The first locking element can be, for example, one or more locking projections that extend laterally from a side of the blade tang. The second locking element can be one or more locking notches that are sized to receive the locking projections when the blade is in open and/or closed positions.
[0005] The blade can be mounted on a leaf spring in the handle for pivotal movement relative to the handle between the open and closed positions. The leaf spring functions to support the blade and provide a biasing force that resiliently biases in a direction laterally toward the second locking element on the handle. The leaf spring causes the first locking element to engage the second locking element when the blade is pivoted to the open position and/or when the blade is pivoted to the closed position. The blade can be released from being locked in the open or closed positions by applying manual pressure to the blade against the biasing force of the leaf spring to move the first locking element out of engagement with the second locking element. The blade can have a button or projection that extends laterally from one side of the blade and has an exposed end surface at one side of the handle that can be pressed inwardly to move the first locking element out of engagement with the second locking element.
[0006] In one representative embodiment, a folding knife comprises a handle and a blade. The blade has a tang that is pivotably connected to the handle and is pivotable relative to the handle about a pivot axis between a closed position and an open position. The tang comprises a laterally extending projection and at least one laterally extending locking element. The handle comprises first and second, laterally spaced side portions, the first side portion comprising an aperture and at least one locking notch in communication with the aperture. The projection of the blade tang extends laterally into the aperture such that the projection can rotate within the aperture when the blade is pivoted between its open and closed positions. The second side portion comprises a leaf spring having a free end portion that is resiliently biased toward the first side portion. The free end portion pivotably supports the blade tang by a pivot element extending through the blade tang and the free end portion. The free end portion exerts a biasing force laterally against the blade such that when the blade is pivoted to its open position, the biasing force urges the blade into an open and locked position in which the locking element on the blade extends into and engages the locking notch. The blade can be released from the open and locked position by manually moving the blade laterally against the biasing force to move the locking element out of engagement with the locking notch.
[0007] In another representative embodiment, a folding knife comprises a handle and a blade having a tang that is pivotably connected to the handle. The blade is pivotable relative to the handle about a pivot axis between a closed position and an open position. The tang has at least a first locking element. The handle comprises first and second, laterally spaced side portions, the first side portion comprising at least a second locking element adapted to engage the first locking element when the blade is pivoted to its open position. The second side portion comprises a leaf spring having a free end portion that supports the blade tang for pivoting movement of the blade. The free end portion is configured to apply a biasing force that urges the blade toward the second side portion such that when the blade is pivoted to its open position, the biasing force causes the blade to move toward the second side portion and cause the first locking element to engage the second locking element so as to lock the blade in the open position.
[0008] In another representative embodiment, a folding knife comprises a handle and a blade having a tang that is pivotably connected to the handle. The blade is pivotable relative to the handle about a pivot axis between a closed position and an open position. The tang has first locking means. The handle comprises a leaf spring having a free end portion that supports the blade tang for pivoting movement of the blade. The handle further comprises second locking means for engaging the first locking means when the blade is in its open position. The free end portion of the leaf spring is configured to apply a biasing force against the blade such that when the blade is pivoted to its open position, the biasing force causes the blade to move laterally toward the second locking means to cause the first locking means to engage the second locking means so as to lock the blade in the open position.
[0009] The foregoing and other features and advantages of the invention will become more apparent from the following detailed description, which proceeds with reference to the accompanying figures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a perspective, exploded view of a folding knife, according to one embodiment.
[0011] FIG. 2 is a perspective view of the folding knife of FIG. 1 .
[0012] FIG. 3 is a perspective view of the blade of the folding knife of FIG. 1 .
[0013] FIG. 4 is side view of the folding knife of FIG. 1 shown with one side of the handle removed for purposes of illustration.
[0014] FIG. 5 shows the opposite side of the folding knife shown in FIG. 4 .
[0015] FIG. 6 is a side view of one of the frame portions of the folding knife of FIG. 1 having an integral leaf spring and belt clip.
[0016] FIG. 7 is a top plan view of the frame portion shown in FIG. 6 .
[0017] FIG. 8 is a side view of the folding knife of FIG. 1 shown with the blade in the open position.
[0018] FIG. 9 is a side view of the folding knife of FIG. 1 shown with the blade in the open position.
[0019] FIG. 10 is a top plan view of the folding knife of FIG. 1 shown with the blade in the open position.
[0020] FIG. 11 is a bottom plan view of the folding knife of FIG. 1 shown with the blade in the open position.
[0021] FIG. 12 is an exploded view of a blade and an optional push button that is connected to a side of the blade.
[0022] FIG. 13 is a side view of an alternative embodiment of a frame portion having an integral leaf spring for supporting the blade.
DETAILED DESCRIPTION
[0023] Referring to the drawings, a folding knife 10 , according to one embodiment, comprises a handle 12 and a knife blade 14 pivotably connected to the handle 12 . The blade is pivotable relative to the handle between a closed position for storing the blade ( FIG. 8 ) and an open position for using the blade ( FIG. 9 ). The handle 12 comprises a first frame portion 16 (also referred to as a first side portion) and a second frame portion 18 (also referred to a second side portion) separated by a spacer, or spline, 20 . Screws 58 can be used to secured the spacer 20 to the frame portions 16 , 18 . A blade receiving channel is defined between the first and second frame portions 16 , 18 for receiving the blade in the closed position. The handle 12 can further include a forward spacer 56 secured between the frame portions 16 , 18 adjacent the blade. The forward spacer 56 can also function as a blade stop that contacts the blade when it is folded closed to prevent further pivoting of the blade past the closed position. Although not shown in the drawings, the handle can also include scales and/or bolsters secured to the outer surfaces of the frame portions 16 , 18 . Such scales and/or bolsters can be used for decorative or aesthetic reasons.
[0024] The second frame portion 18 comprises a main body 24 and a biasing element in the form of, for example, a leaf spring 22 that can be integrally formed in the main body 24 of the second frame portion as depicted. In the context of the present application, the phrase “integrally formed” or “integrally connected” means that the leaf spring is machined, cut, or otherwise formed from the same piece of material that forms the main body without any fasteners or welds securing the leaf spring to the main body. In alternative embodiments, however, the biasing element (e.g., leaf spring 20 ) can be separately formed and subsequently connected to the main body 24 second frame portion, such as with mechanical fasteners or by welding the biasing element to the main body.
[0025] As best shown in FIG. 6 , the leaf spring 22 has a distal free end portion 26 and a proximal fixed end portion 28 that is integrally connected to the main body 24 of the second frame portion. Referring to FIG. 1 , the blade 14 has a tang portion 30 that is pivotably connected to the free end portion 26 of the leaf spring, such as by a pivot element, or pivot pin, 32 that extends through a central opening 34 of the free end portion 26 , a washer 60 , and a corresponding opening in the blade tang 30 . A pivot screw 36 extends and is tightened into a threaded bore of the pivot pin 32 in a conventional manner.
[0026] The leaf spring 22 functions to bias the blade 14 laterally toward the first frame portion 16 to lock the blade in the open and/or closed positions, as further described below. In alternative embodiments, the biasing element can take other forms, such as a coil spring or other resilient member interposed between the blade and the second frame portion.
[0027] The second frame portion 18 can also include a spring clip 38 for clipping the knife to a pocket, belt, etc. The clip 38 can be integrally formed as shown or separately formed and subsequently attached to the second frame portion or at another location on the handle. As best shown in FIG. 7 , the leaf spring 22 is bent to extend laterally outwardly from one side of the second frame portion and the spring clip 38 is bent to extend laterally outwardly from the opposite side of the second frame portion.
[0028] The blade tang 30 in the illustrated embodiment includes a laterally extending main projection 40 and one or more laterally extending first locking elements in the form of locking pins, or projections, 42 . The first frame portion 16 is formed with a main opening 44 that is complementary to the projection 44 and one or more second locking elements in form of locking notches 46 in communication with the main opening 44 that are sized to receive the locking pins 42 . In the illustrated embodiment, as best shown in FIG. 1 , the locking pins 42 are positioned on diametrically opposed sides of the main projection 40 and extend laterally from one side of the blade tang a distance less than the main projection.
[0029] Desirably, the main projection 40 has a circular cross-sectional profile (perpendicular to the pivot axis of the blade) and the main opening 44 is circular to allow the main projection 40 to rotate within the main opening 44 when the blade is pivoted from the closed position to the open position, and vice versa. The main projection 40 desirably extends slightly beyond the outer side surface of the second frame portion 16 and has an exposed end surface 54 at the side of the handle that serves as a button or pressing surface for applying manual pressure against the blade when unlocking the knife. In the illustrated configuration, the main projection 40 is integrally formed as part of the blade tang. It should be noted, however, that the projection 40 can be separate component that is held in place against the side of the blade tang 30 by the pivot pin 32 .
[0030] When the blade is in the closed position ( FIG. 8 ), the locking pins 42 are received in the notches 46 . The spring force of the leaf spring 22 forces the blade laterally against the first frame portion 16 (as indicated by arrow 48 in FIG. 10 ), thereby retaining the locking pins 42 in the notches and preventing rotation of the blade relative to the handle. To open the blade, the user first applies a manual force against the main projection 40 in a direction laterally toward the second frame portion 18 (as indicated by arrow 50 in FIG. 50 ) sufficient to overcome the force of the leaf spring and move the blade laterally a distance until the locking pins 42 are moved out of the notches 46 .
[0031] While maintaining manual pressure laterally against the blade to keep the locking pins out of the notches, the blade can be pivoted to the open position by applying a rotational force to the blade in a conventional manner. To assist in rotating or “flipping” the blade open, the blade can include projections 52 (referred to as “flippers’). When the blade reaches the open position (which is about 180 degrees from the closed position in the illustrated embodiment), the locking pins 42 become aligned with the notches 46 and the leaf spring 22 forces the locking pins into the notches so as to lock the blade in the open position (referred to as the open and locked position). The blade can be pivoted closed in a similar manner by first moving the blade laterally to move the locking pins out of the corresponding notches and then rotating the blade until it reaches the closed position and the locking pins again become aligned with the notches, allowing the leaf spring to push the locking pins into the notches.
[0032] In the illustrated embodiment, there are two locking pins 42 extending from the side of the blade and a corresponding number of locking notches. In other embodiments, the blade can have only one locking pin 42 or more than two locking pins spaced around the main projection 40 , and a corresponding number of locking notches. Also, the number of locking notches need not correspond to the number of locking pins. For example, the blade can have one locking pin 42 and the handle can have two locking notches, one of which is positioned to receive the locking pin when the blade is open and the other of which is positioned to receive the locking pin when the blade is closed.
[0033] Moreover, in alternative embodiments, the positions of the locking pins 42 and the locking notches 46 can be reversed. In other words, the blade tang 30 can be formed with one or more locking notches and the first frame portion 16 can have one or more complimentary locking pins or projections that extend into the notches on the blade.
[0034] In the illustrated embodiment, the blade is configured to pivot 180 degrees between the open and closed positions. Also, the locking pins 42 are spaced 180 degrees apart from each other, and so are the locking notches 46 . As such, the locking pins 42 can extend into and engage the locking notches 46 when the blade is in the closed position and the open position. However, it should be noted that the positions of the locking pins 42 and/or the locking notches 46 and/or the rotation of the blade can be modified to allow the locking pins 42 to engage the locking notches in the open position or the closed position but not both.
[0035] For example, the locking pins 42 can be positioned so that they are aligned with the locking notches 46 when the blade is in the open position and the blade can be configured to pivot about 175 degrees. Thus, in this specific example, the locking pins 42 extend into the locking notches 46 when the blade is opened (and therefore lock the blade in the open position), but when the blade is pivoted closed, the locking pins 42 do not become aligned with the locking notches 46 since the blade does not rotate a full 180 degrees. As such, the locking pins 42 cannot engage the locking notches to lock the blade in the closed position. Instead, the locking pins 42 bear against the inner surface of the first frame portion 16 under the force of the leaf spring 22 . The force of the leaf spring 22 pressing the locking pins 42 against the inner surface of the first frame portion 16 desirably is sufficient to keep the blade from opening under its own weight. In this manner, the locking mechanism (including the locking pins and the locking notches) locks the blade in the open position and protects against inadvertent closing of the blade while the blade is being used, and when the blade is closed, the locking mechanism is effectively inactive or non-engaged so that the blade can be easily pivoted from the closed position without having to first manually disengage the locking mechanism.
[0036] As noted above, referring to FIG. 8 , the blade can include projections 52 to assist in opening the blade. The projections 52 desirably are non-parallel to each other and desirably are oriented at an angle of about 10 to 170 degrees relative to each other, with 90 degrees being a specific example. The projections 52 can be used to open the blade in several different ways. For example, the blade can be opened by applying a rotating force to the upper projection 52 in FIG. 8 (usually with the index finger) while simultaneously flicking the wrist with sufficient force to completely open the blade. In another example, the blade can be opened by applying a rotating force to the lower projection 52 in FIG. 8 with the thumb. Due to the position of the lower projection 52 , the blade can be pivoted through its full range using only the thumb. In another example, the blade can be opened using only the index finger (and without flicking the wrist) by first applying a rotating force to the upper projection 52 with the index finger to partially open the blade and then subsequently applying a rotating force to the lower projection 52 to further pivot the blade from the partially open position to the fully open position.
[0037] If desired, an optional button, or extension, 82 ( FIG. 12 ) can be coupled the main projection 40 so as to extend laterally outwardly from the main opening 44 in the frame portion 16 . The button 82 is exposed at the side of the side of the handle and can be depressed by a user to move the blade laterally against the bias of the leaf spring when unlocking the blade.
[0038] FIG. 13 illustrates an alternative frame portion 100 that can be used in lieu of frame portion 18 . In this embodiment, the entire distal end portion 102 of the frame portion 100 functions as the leaf spring and supports the blade in a pivotable manner, such as via a pivot pin that extends through an opening 104 . The frame portion 100 can be formed with an optional belt clip 106 .
[0039] In view of the many possible embodiments to which the principles of the disclosed invention may be applied, it should be recognized that the illustrated embodiments are only preferred examples of the invention and should not be taken as limiting the scope of the invention. Rather, the scope of the invention is defined by the following claims. I therefore claim as my invention all that comes within the scope and spirit of these claims.
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The present disclosure concerns embodiments of a folding knife having a locking mechanism for locking a blade in open and/or closed positions. The locking mechanism a first locking element on the blade and a corresponding second locking element on the handle that is adapted to engage the first locking element when the blade is in open and/or closed positions. The blade can be mounted on a leaf spring in the handle for pivotal movement relative to the handle between the open and closed positions. The leaf spring functions to support the blade and provide a biasing force that resiliently biases in a direction laterally toward the second locking element on the handle.
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FIELD OF THE INVENTION
[0001] The present invention is directed towards a crane grab head for picking up floor mats.
BACKGROUND OF THE INVENTION
[0002] In situations where vehicular or pedestrian access is required on certain plots of land, for instance arable land, road or floor mats are often laid to act as a temporary surface to prevent damage to this underlying land.
[0003] The floor mats used are generally modular and are usually inserted into position by the use of a crane.
[0004] An example floor mat used is the DURA-BASE™ mat by Terrafirma Roadways. A perspective view of this mat is shown in FIG. 1 . The mat is formed of two overlapping rectangular sections. Holes extend around the perimeter of the mat along the non-overlapping portions of the two sections. When two of these mats are placed next to each other, the mats overlap and the holes along the common edge of these two mats line up such that a temporary locking pin can be placed through the holes of both mats to secure the two mats together.
[0005] Given their shape and size, handling and placing these mats into position has proved difficult.
[0006] One method which has been used has chains which anchor to the four corners of the mat. The chains then connect to a crane arm which lifts the mat. The problem with this lifting method is that the chains are flexible making accurate manoeuvring and placing of the mat difficult.
[0007] Alternatively, the mat has been placed onto a forklift. When in the correct position, the forklift operator angles the rails of the forklift downward causing the mat to slide off into position. The method is slow and can cause damage to the mats as they are positioned.
[0008] An improved method for lifting these mats is a grab device from Terrafirma which allows mats, in particular DURA-BASE TM mats, to be gripped, lifted, and placed into position. The present invention relates to improvements to this grab device.
SUMMARY OF THE INVENTION
[0009] According to one aspect of the present invention, there is provided a crane grab head comprising a pair of jaws, a power source for moving the jaws, and a connector for connecting the grab head to a crane, wherein each jaw comprises at least one tooth for engaging with an object;
wherein each jaw is driven by a respective hydraulic/pneumatic cylinder which is slideable linearly to move the jaws between open and closed positions; wherein the width of the grab head measured between the extremities of the jaws in the closed position is more than 1500 mm; and wherein the separation between a horizontal plane passing through the top of the uppermost cylinder when the head is held freely in normal use and a parallel plane passing through the lowermost edge of the lowermost tooth is less than 250 mm.
[0013] The defined separation essentially represents the maximum height of the grab head excluding the connector. By minimising this separation, the bending moment applied to each tooth when the grab grips a mat is reduced. Reducing the bending moment reduces the chance of each tooth breaking during the gripping process, and thus increases the number of mats which can be positioned by the grab head before a tooth fails. This is of particular importance considering each tooth may be cyclically loaded between a gripping position and a non-gripping position hundreds of times a day.
[0014] Also keeping the vertical separation to less than 250 mm allows the grab head to be more conveniently stowed when it is not in use.
[0015] The teeth on both jaws may be level with one another. However, preferably the separation on one side is greater than the separation on the other.
[0016] This may be achieved either by offsetting the cylinders for the two jaws, or by having the jaws and/or teeth on one side larger than the other.
[0017] The offsetting of the teeth between the two jaws in the grab head means that teeth on one jaw are lower than those on the other. This allows the grab head to pick up objects which are not necessarily flat or which are stepped; for instance a DURA-BASE TM mat, while still maintaining the resultant closing force on the jaws generally in line with the cylinders.
[0018] The hydraulic/pneumatic cylinders may be arranged to pull together and push apart the pairs of jaws with equal force either way. This capability of the jaws to grip by either pulling and pushing means that the grab head can be used with much greater flexibility and allows the grab head to separate two mats by pulling them apart in a generally horizontal plane. Existing grab heads are not designed to do this and attempts to do so have resulted in premature breakage of the grab head.
[0019] According to a second aspect of the present invention, there is provided a crane grab head comprising a pair of jaws, a power source for moving the jaws, and a connector for connecting the grab head to a crane, wherein each jaw comprises at least one tooth for engaging with an object;
wherein each jaw is driven by a respective hydraulic/pneumatic cylinder which is slideable linearly to move the jaws between open and closed positions; wherein the width of the grab head measure between the extremities of the jaws in the closed position is more than 1500 mm; and wherein the tooth/teeth of the first jaw are spaced further beneath the cylinders when the head is held freely in normal use than are the tooth/teeth of the other jaw.
[0023] As previously described, the offsetting of the teeth between the two jaws in the grab head allows it to pick up objects which are not necessarily flat or which are stepped; for instance a DURA-BASE™ mat, while still maintaining the resultant closing force on the jaws generally in line with the cylinders.
[0024] At least one of the pair of jaws may comprise a visual indication which allows the pair of jaws to be distinguished from each other. The visual indication may be the fact that one jaw is coloured differently than the other jaw.
[0025] According to a third aspect of the present invention, there is provided a crane grab head comprising a pair of jaws, a power source for moving the jaws, and a connector for connecting the grab head to a crane, wherein each jaw comprises at least one tooth for engaging with an object;
wherein each jaw is driven by a respective hydraulic/pneumatic cylinder which is slideable linearly to move the jaws between open and closed positions; wherein the width of the grab measured between the extremities of the jaws in the closed position is more than 1500 mm; and wherein the pneumatic/hydraulic cylinders are arranged to pull together and push apart the pairs of jaws with equal force either way.
[0029] The ability of the grab head to push apart the pairs of jaws allows it to separate two mats in a manner not possible with the prior art described above.
[0030] Each jaw may comprise more than one tooth. By increasing the number of teeth present in the grab head, the pressure acting on each tooth by the power source is reduced.
[0031] Each tooth preferably comprises a step which extends for less than 15 mm in the direction toward the other jaw, and which is configured to grip a complimentary shoulder of an object.
[0032] The cylinders each may have a sold circular cross section. This cross section is preferable to the square cross section currently employed as it reduces the friction losses present in each cylinder. Reducing the friction in each cylinder contributes to the grab head having a low profile since the reduced friction allows the cross sectional width of each cylinder to be reduced.
[0033] The grab head may be provided in conjunction with a jaw adaptor which is fastened to one of the jaws, wherein the jaw adaptor comprises at least one auxiliary tooth to take over the role of the tooth/teeth of the jaw to which the adaptor is fastened, such that the adaptor allows the separation between the auxiliary tooth/teeth and the tooth/teeth of the other jaw to be changed as compared to the separation between the tooth/teeth on the jaws without the adaptor in place. The grab head may be provided in conjunction with a floor element wherein the teeth are configured to grip the floor element. The floor element may be in particular a DURA-BASE™ mat.
BRIEF DESCRIPTION OF THE DRAWINGS
[0034] An example of an apparatus in accordance with the present invention will now be described with reference to the accompanying drawings, in which:
[0035] FIG. 1A shows a perspective view of a DURA-BASE™ floor mat;
[0036] FIG. 1B shows a plan view of the mat;
[0037] FIG. 1C shows a side view of the mat;
[0038] FIG. 2A shows a plan view of a crane head according to the present invention;
[0039] FIGS. 2B and 2C show perspective views of this crane head;
[0040] FIG. 3 shows a detailed cross section view of the mat taken across the plane X-X from FIG. 1B when the crane head is grabbing the mat.
[0041] FIGS. 4 and 5 each show a side view of a crane placing a gripped mat into position next to an already positioned mat.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0042] FIGS. 1A-1C show views of a floor mat 10 , or floor element, which the grab head of the present invention is designed to grip. The mat 10 is formed of a top and bottom sheet of material 11 ; 12 which overlap each other.
[0043] Each mat 10 or sheet of material 11 ; 12 is formed of any appropriate material that can withstand the load of a vehicle passing over it. Preferably each mat can support a load weight of 40 tonnes/m 3 . The mat 10 has a density less than that of water so that it can float on water when loaded less than 250 kg.
[0044] The two sheets 11 ; 12 of the mat 10 are slightly displaced horizontally and laterally from one another such that only the top sheet 11 is present along two neighbouring sides of the mat 10 , and only the bottom sheet 12 is present along the remaining two sides of the mat 10 .
[0045] Where the two sheets 11 ; 12 do not overlap, a number of holes 13 extend through the projections of sheets 11 ; 12 . The cross section of each of these holes 13 is shown in FIG. 3 . The distance between the holes may be fixed to a certain spacing so that the holes 13 form hole sets, for example A-A; B-B; and C-C as shown in FIG. 1A . As will be described, these sets are the points where the grab head picks up the mat 10 .
[0046] As shown in FIG. 3 , a top and bottom ridge 14 ; 15 extends around the top and bottom edges of each hole 13 .
[0047] To lift the mat 10 , the crane head 100 as shown in FIG. 2 is used. The crane head 100 is formed of first and second jaws 102 ; 104 which connect to a central portion 106 via hydraulics or pneumatic actuation cylinders 108 a ; 108 b and telescopic supports 109 a - d. Each cylinder and support comprises a rod which slides between an open and closed position. The cylinders 108 a ; 108 b are coplanar and are orientated parallel with each other. The supports 109 a - d are also coplanar and are orientated parallel with each other.
[0048] The first and second jaws 102 ; 104 each comprise two teeth 110 . Each tooth 110 extends downwardly from the jaw and terminates with a flange 112 which extends in the direction toward the other jaw. The extension of the flange towards the other jaw is preferably less than 15 mm in length, though is more preferably 12 mm.
[0049] Although the teeth 110 on each jaw 102 ; 104 are shaped the same and have the same dimensions, the teeth 110 on the first jaw are located closer to the cylinders than are the teeth 110 on the second jaw. The difference in height between the two sets of teeth may be approximately 50 mm. To help the crane operator identify which jaw has the higher set of teeth, and thus identify which is the first jaw, the first jaw comprises a highly visible indication positioned at the top of the jaw. The indication may be in that the first jaw is a different colour to that of the second jaw.
[0050] Each of the two jaws is connected to the central portion of the crane head by one of the two actuation cylinders 108 a ; 108 b and two of the four supports 109 a - d. Two of the supports 109 a ; 109 c connect the central portion 106 to the first jaw 102 , whilst the remaining two supports 109 b ; 109 d connect the central portion 106 to the second jaw 104 . To provide maximum support to the jaws whilst they are being moved, the two supports on each jaw are located on either side of the actuation cylinder for the jaw, which is more centrally located on the jaw.
[0051] Each of the two actuation cylinders 108 a ; 108 b operates in a telescopic fashion such that the distance between each jaw and the central portion can be varied. Each of the cylinders 108 a ; 108 b may also be configured as a double acting ram 111 to allow either a pulling or pushing force to be applied. In this case, each cylinder 108 a ; 108 b comprises a hydraulic/pneumatic port 113 on either side of the ram head 115 to allow it to move both ways.
[0052] At the top of the central portion 106 is a servo-motor or stepper-motor 114 in combination with a pivot joint 116 which allows the grab head to be connected to the remaining part of the crane and also rotated and angled as needed. Electrical connections and pressure lines from the grab head also connect to the remaining part of the crane via the central portion 106 .
[0053] An equaliser valve is used to distribute fluid pressure from a hydraulic/pneumatic pressure source on the crane to each of the cylinders 108 a ; 108 b on the grab head. From the equaliser valve, any conventional hydraulic/pneumatic pressure system can be used to control operation of the double acting ram in each cylinder.
[0054] The vertical separation between the bottom of the lowermost tooth/teeth of the grab head and the top of the cylinders is preferably as small as possible to ensure ease of stowage and minimise the bending moment exerted on each tooth when they are gripping an object. In the form shown in FIG. 2 , the separation between a horizontal plane passing through the top of the uppermost cylinders when the head is held freely in normal use and a parallel plane passing through the lowermost edge of the lowermost tooth is less than 250 mm.
[0055] Operation of the crane head is shown best with reference to FIG. 1A and FIG. 3 . As previously described, the mat 10 comprises a series of hole sets A-A; B-B; and C-C. The separation between the holes in each sheet from these sets is the same. The separation and size of each hole in each set is also such to allow the two teeth from each jaw of the crane head to pass through all the holes in the set.
[0056] Taking the example of the four holes indicated by hole set A-A, in use the crane operator initially orientates the crane head, via the stepper-motor 114 and the pivot joint 116 , and spaces the jaws, via the cylinders 108 a ; 108 b, such that the teeth from the first jaw are positioned over the two holes from the hole set which are located on the top sheet 11 and the teeth from the second jaw are positioned over the remaining two holes from the hole set located on the bottom sheet 12 .
[0057] The crane operator then lowers the crane head such that the teeth enter the holes A-A of the mat into the dotted position as shown in FIG. 3 . In situations where the mat 10 is placed flat on the ground, the operator will know when the teeth are in the dotted position shown in FIG. 3 since he will feel resistance in the movement controls of the crane due to the bottom of the teeth in the second jaw making contact with the ground.
[0058] From this dotted position, the operator then moves the jaws together via the cylinders 108 a ; 108 b such that the flange of each tooth overlaps the bottom ridge 15 of each hole 13 to grip and lift the mat as shown in FIG. 4 .
[0059] From the dotted position, the operator alternatively may move the jaws apart, rather than bring them together, such that the outer face of each tooth makes contact with the outer edge of each hole 13 . Moving the jaws outward provides an alternative way of gripping the mat.
[0060] The crane operator then releases the teeth from engagement with the edges of the holes, using the cylinders, and returns the jaws to the dotted position shown in FIG. 3 . From here, the crane operator then raises the crane head away from the newly positioned mat.
[0061] The two mats can then be secured together by a locking pin or any other fastening means.
[0062] The above process can then be repeated with a new mat as required.
[0063] In some instances, it may be that the crane operator wishes to place a mat alongside an already positioned mat which has a top sheet, rather than a bottom sheet, sticking out. In this case, the crane operator must slide the bottom sheet of the new mat underneath the top sheet of the already positioned mat to allow the two mats to be connected.
[0064] To slide the new mat underneath the already positioned mat, the operator first places the new mat next to the already placed mat as shown in FIG. 5 . The operator then disconnects the second jaw from the mat, tilts the crane head from the new mat, and then expands the second jaw, which previously engaged with the pair of holes in the lower sheet of the new mat, such that it engages with the pair of holes in the upper sheet of the already placed mat. In this position, as the first and second jaws are each connected to a pair of holes in an upper sheet of a mat, the grab head may be slightly angled from the horizontal to compensate for the fact that the teeth of the second jaw are positioned slightly lower than the teeth from the first jaw.
[0065] Once both the jaws are engaged with their holes in the upper sheets of the mats, the operator pulls the jaws together using the cylinders 108 a ; 108 b. Since the weight of the crane is acting on the already placed mat, when the jaws are pulled together the new mat is the mat which moves. Thus the bottom sheet of the new mat slides underneath the top sheet from the already positioned mat and into a position for fastening.
[0066] To separate the new mat from the already positioned mat after use, the previously described process is reversed as follows:
i) the crane is positioned on the already placed mat as shown in FIG. 5 . The grab head is then slightly angled from the horizontal such that the teeth from the second jaw are positioned in the holes of the upper sheet in the already placed mat and the teeth from the first jaw positioned in the holes of the upper sheet in the new mat; ii) once both the jaws are engaged with their respective holes as in i), the operator then pushes the jaws apart using the cylinders 108 a ; 108 b such that the outer face of the teeth in the first jaw make contact with the outer edge of each hole 13 . Since the weight of the crane is acting on the already placed mat, when the jaws are pushed apart the new mat slides laterally out from under the already placed mat (which remains stationary) into the position shown in FIG. 5 ; iii) once the new mat is in the position shown in FIG. 5 , the new mat is then lifted as previously described (by re-engaging the flange of each tooth with the bottom ridge 15 of each hole 13 ).
[0070] The ability to push two mats apart may be useful in situations other than the one described above if two mats are stuck together.
[0071] Thus it will be appreciated that the outer side of each tooth can be used to separate two mats apart and the inner side of each tooth can be used to bring two mats together. However, only the inner side of each tooth, which comprises the flange which engages with the ridge in the mat, is used to lift the mat.
[0072] Whenever a mat is gripped, it is preferable to use hole set A-A, rather than B-B or C-C. As the holes in A-A are the most centrally located on the mat, gripping the mat with these holes reduces the bending forces exerted on the teeth when the mat is lifted.
[0073] In some embodiments of the grab head, one or both of the jaws may include a detachable adaptor. The adaptor includes a further tooth which is similar in shape to any of the other teeth previously described. The purpose of this auxiliary tooth is to take over the role of the teeth of the jaw to which the adaptor is fastened, such that the adaptor allows the separation between the auxiliary tooth and the teeth of the other jaw to be changed as compared to the separation between the teeth on the jaws without the adaptor in place.
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A crane grab head ( 100 ) comprising a pair of jaws ( 102;104 ), a power source for moving the jaws, and a connector ( 116 ) for connecting the grab head ( 100 ) to a crane, wherein each jaw ( 102;104 ) comprises at least one tooth ( 110 ) for engaging with an object. Each jaw ( 102;104 ) is driven by a respective hydraulic/pneumatic cylinder ( 108 a; 108 b) which is slideable linearly to move the jaws ( 102;104 ) between open and closed positions. The width of the grab measured between the extremities of the jaws ( 102;104 ) in the closed position is more than 1500 mm. The separation between a horizontal plane passing through the top of the uppermost cylinder ( 108 a; 108 b ) when the head ( 100 ) is held freely in normal use and a parallel plane passing through the lowermost edge of the lowermost tooth ( 110 ) is less than 250 mm.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates to an interference device, a position detecting device, a positioning device and an information recording apparatus using the same. This invention can be applied particularly well to a position detecting device for detecting the positional fluctuation of an object in non-contact such as an interference length measuring device for an object like a hard disc drive magnetic head, a positioning device and a manufacturing apparatus for a hard disc drive device (hereinafter referred to as HDD) used in a computer utilizing the same, and above all, an apparatus for writing a servo track signal into a hard disc in the HDD.
[0003] 2. Related Background Art
[0004] [0004]FIG. 1A of the accompanying drawings shows an illustration of an apparatus for writing a servo track signal into a hard disc in the HDD according to the conventional art.
[0005] In FIG. 1A, HDD designates a hard disc drive device, HD denotes hard discs, SLID designates a slider, ARM 1 denotes a magnetic head arm, VCM designates a voice coil motor, OHD denotes the spindle of the hard discs HD, and O designates the rotary shaft of the magnetic head arm ARM 1 .
[0006] A magnetic recording medium is deposited by evaporation on the surface of each hard disc. The hard discs HD are normally rotated as a unit at a high speed about the spindle OHD, and a magnetic head is disposed in proximity to the surface of each hard disc HD. The magnetic head is incorporated in the portion of a substantially rectangular parallelopiped called the slider SLID mounted on the tip end of each arm portion of the magnetic head arm ARM 1 having the center of rotation O outside the hard discs HD, and is relatively movable substantially in a radial direction on the hard discs HD by rotatively driving the arm ARM 1 by the voice coil motor VCM.
[0007] Consequently, magnetic information can be written or read at any position (track) on the surfaces of the hard discs by the rotated hard discs HD and the arcuately moved magnetic head.
[0008] Now, a magnetic recording system onto the surface of the hard disc is such that each hard disc is splitted into a plurality of circular ring-shaped tracks of different radii concentric with the center of rotation OHD of the hard discs, and further each of the circular ring-shaped tracks in turn is splitted into a plurality of arcs and finally, magnetic information is recorded and reproduced on the plurality of arcuate areas time-serially along the circumferential direction.
[0009] Now, as the recent tendency, an increase in the recording capacity of the hard disc is required and there is a desire for the higher density of recorded information onto the hard disc. As means for the higher density of recorded information onto the hard disc, it is effective to narrow the width of the tracks splitted into concentric circles and improve the recording density in the radial direction.
[0010] The recording density in the radial direction is expressed by track density TPI (track/inch) per length of an inch, and at present it is of the order of 10000 TPI. This means that the track interval is about 3μ. To form such a minute track pitch, it is necessary to position the magnetic head at resolving power (0.05μ) of about 1/50 of the track width in the radial direction of the hard disc HD and write a servo track signal in advance into the hard disc. The important technique here is to successively write servo track signals into the hard disc while effecting positioning of high resolving power within a short time.
[0011] PROD designates a push rod, ARM 2 denotes an arm for the push rod PROD, MO designates a positioning control motor, RE denotes a rotary encoder for detecting the amount of rotation of the rotary shaft of the motor MO, SP designates a signal processor for analyzing the detection output from the rotary encoder RE, and producing a positioning command signal to the servo track signal writing-in position of the magnetic head, and MD denotes a motor driver for driving the motor MO by the command signal of the signal processor SP. These together form a rotary positioner RTP.
[0012] According to the conventional art, as shown in FIG. 1A, the cylindrical surface of the push rod PROD was pushed against the side of the magnetic head arm ARM 1 (the arm portion for the magnetic head for the underside of the lowermost hard disc), and the arm ARM 2 was rotated to thereby sequentially finely feed and position the magnetic head arm through the push rod PROD while taking feedback control by the system of the rotary encoder RE, the signal processor SP and the motor driver MD, and servo track signals from a signal generator SG were successively written in from the magnetic head. In order to ensure the contact at this time, some electric current was usually supplied to the voice coil motor VCM and the push rod PROD was also pushed from the head arm ARM 1 side.
[0013] Recently, supposing more highly accurate positioning, a non-contact method of highly accurate measuring the movement of the magnetic head arm by optical means has been desired without adopting a system for mechanically pushing the magnetic head arm in which the vibration by the rotation or the like of the hard disc may be transmitted to the motor MO. FIG. 1B of the accompanying drawings shows an example of such an apparatus.
[0014] In FIG. 1B, HeNe designates a laser light source, M 1 and M 2 denote mirrors, BS designates a beam splitter, CC denotes a retroreflector such as a corner cube provided on the magnetic head arm ARM 1 , and PD designates a light receiving element.
[0015] In this apparatus, the laser light source HeNe, the mirrors M 1 and M 2 , the beam splitter BS and the retroreflector CC together constitute a Michelson type interferometer, and the interference light of light beams L 1 and L 2 which have passed the retroreflector CC and the mirrors M 1 and M 2 , respectively, is detected by the light receiving element PD to thereby obtain the positional information of the magnetic head arm ARM 1 . On the basis of the obtained detection signal, a signal processor SP produces a command and controls an electric current flowing from a voice coil motor driver VCMD to a voice coil motor VCM to thereby directly move the magnetic head arm and provide appropriate control.
[0016] In such an apparatus, however, it is necessary to place the retroreflector CC such as a corner cube on the magnetic head arm, and this is liable to lead to the problem of troubles such as the securement of space and the mounting and dismounting of the retroreflector, and the aggravation of the control characteristic by an increase in weight.
SUMMARY OF THE INVENTION
[0017] In view of the above-described examples of the conventional art, the present invention has as an object thereof to provide a position detecting device and a positioning device capable of detecting the position of an object and position the object in non-contact at high reliability and with high accuracy and high resolving power, an interference device making the same realizable and an information recording apparatus using the same.
[0018] Other objects of the present invention will become apparent from the following description of some embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] [0019]FIG. 1A is an illustration of a prior-art servo track signal writing-in apparatus using a hard disc drive device and a push rod.
[0020] [0020]FIG. 1B is an illustration of a prior-art servo track signal writing-in apparatus using a hard disc drive device and a retroreflector interference length measuring machine.
[0021] [0021]FIG. 2A schematically shows the construction of a servo track signal writing-in apparatus according to Embodiment 1 of the present invention.
[0022] [0022]FIG. 2B is an illustration of the optical type non-contact distance sensor unit of the servo track signal writing-in apparatus shown in FIG. 2A.
[0023] [0023]FIG. 3 is an illustration of the optical type non-contact distance sensor unit of a servo track signal writing-in apparatus according to Embodiment 2 of the present invention.
[0024] [0024]FIG. 4 schematically shows the construction of a servo track signal writing-in apparatus according to Embodiment 3 of the present invention.
[0025] [0025]FIG. 5 is an illustration of the optical type non-contact distance sensor unit and probe holder of the servo track signal writing-in apparatus shown in FIG. 4.
[0026] [0026]FIG. 6 is an illustration of the optical type non-contact distance sensor unit and probe holder of a servo track signal writing-in apparatus according to Embodiment 4 of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0027] [0027]FIG. 2A schematically shows the construction of a servo track signal writing-in apparatus according to a first embodiment of the present invention. In FIG. 2A, members similar to those in the aforedescribed conventional art are given the same reference characters.
[0028] A hard disc drive device HDD has mounted thereon a magnetic head arm ARM 1 having a rotary shaft O outside a hard disc HD, and a slider SLID mounted on the tip end thereof is disposed with a gap of 0.5 μm (or less) in opposed relationship with the surface of the hard disc, and is arcuately moved by the rotation of the magnetic head arm ARM 1 . The rotation of the magnetic head arm is effected by an electric current being supplied to a voice coil motor VCM.
[0029] Such an apparatus is disposed at a spatially proper position, as shown in FIG. 2A, relative to the hard disc drive device HDD comprising the hard disc HD, the slider SLID, the magnetic head arm ARM 1 , the voice coil motor VCM, etc.
[0030] SG designates a signal generator for generating a servo track signal to be written into the hard disc, and this servo track signal is written into the hard disc HD through the magnetic head of the slider SLID.
[0031] A position detecting unit NCPU is provided on a support arm ARM 2 , and the tip end portion of an optical probe NCP may be inserted in a slot-like opening (not shown) in the base plate of the hard disc drive device HDD and is disposed near the side of the magnetic head arm ARM 1 . The support arm ARM 2 is disposed so as to be rotatably movable by a rotary shaft coaxial with the center of rotation O of the magnetic head arm ARM 1 . The rotated position of the position detecting unit NCPU is detected by a high resolving power rotary encoder RE mounted on the rotary shaft of the support arm ARM 2 , and on the basis of this detection data, a signal processor SP 1 rotatively drives a motor MO through a motor driver MD. By the feedback control of this form, the position detecting unit NCPU is rotatively positioned.
[0032] The position detecting unit NCPU is comprised of an optical type sensor unit as will be described hereinafter.
[0033] [0033]FIG. 2B is an illustration of the construction of an optical system for illustrating the optical type sensor unit. The optical type sensor unit is comprised of a multimode laser diode LD, a non-polarizing beam splitter NBS, a probe-like polarizing prism PBS, a reference reflecting surface M, a quarter wavelength plate QWP, a light beam diameter limiting opening AP, a light beam amplitude splitting diffraction grating GBS, polarizing plates PP 1 -PP 4 , photoelectric elements PD 1 -PD 4 , etc.
[0034] Divergent light from the multimode laser diode LD is made into a loosely condensed light beam BEAM by a collimator lens COL, is transmitted through the non-polarizing beam splitter NBS, and then enters the probe-like polarizing prism PBS of an optical probe NCP which is formed of a light-transmitting substance, and is splitted into each polarized component by the light splitting surface of the probe-like polarizing prism PBS. The reflected S-polarized light beam is condensed and illuminated near a beam waist on the side of the head arm ARM 1 disposed in a space spaced apart by about 300 μm from the end surface of the probe-like polarizing prism PBS (here, the arm portion for the magnetic head for the underside of the lowermost hard disc), and the reflected light becomes a divergent spherical wave and returns along the original optical path, and is returned to the light splitting surface of the probe-like polarizing prism PBS. A P-polarized light beam transmitted through the probe-like polarizing prism PBS is condensed and illuminated on the reflecting deposited film of the end surface at a position deviating from the beam waist (short of the beam waist), and the reflected light returns along the original optical path, and is returned to the light splitting surface of the probe-like polarizing prism PBS. The optical path lengths of the two optical paths are set so that the difference between the optical path lengths thereof may be within the coherent distance of the light source, that is, the optical path lengths may be equal to each other.
[0035] Specifically, for example, the shape is given as follows. The width of the probe-like polarizing prism PBS formed of glass is of the order of 2 mm, and the light beam reflected by the polarizing prism PBS travels by 1 mm through the glass and travels by 0.3 mm through the air, and is illuminated on the head arm side ARM 1 . Consequently, the reciprocative wave motion optical path length L1 from the polarizing prism to the reflecting surface is L1=(1×1.5+0.3)×2=3.6. On the other hand, the light beam transmitted through the polarizing prism PBS travels by 1.2 mm through the glass and is illuminated on the end surface of the glass. Consequently, the reciprocative wave motion optical path length L2 is L2=(1.2×1.5)×2=3.6. Here, the refractive index of the glass is 1.5.
[0036] Next, the condensed position (beam waist) of the light beam is set to a position of 0.3 mm after the light beams have emerged from the polarizing prism. Thereupon, the position of the wave source of the divergent spherical wave reflected from the head arm side and the reference reflecting surface looks deviated in the direction of the optical axis. Assuming that the interior of the probe-like polarizing prism is looked into from the light source side, the condensing point (wave source) on the head arm side is seen at a position of L1′=(1+0.3×1.5)=1.45 from the splitting surface of the polarizing prism. The position of the divergent spherical wave source from the reference reflecting surface is seen at a position of L2′=1.2×2−1.45=0.95 from the splitting surface of the polarizing prism. However, the two positions are positions seen in the glass. Consequently, it follows that the two divergent spherical wave sources deviate by 0.5 mm from each other (a difference in the imaging optical path length is created), and when the two light beams are superposed one upon the other, the wavefronts do not completely coincide with each other, and if the two polarized lights are put together, there will be obtained interference fringes like concentric circles. In that case, when the phases of the two wavefronts are fluctuated by the relative movement of the head arm, the interference fringes like concentric circles look gushing out of and inhaled into the center. However, these concentric circular interference fringes are as small as about 0.5 mm in the amount of deviation of the two divergent spherical waves in the direction of the optical axis and therefore, in the central portion thereof, there is widely obtained an interference fringe portion of substantially one color (the same phase). Consequently, an appropriate opening AP is provided so as to take out only the substantially one color portion, thereby taking out some light beam. After this, the interference fringes can be handled as a substantially plane wave.
[0037] Now, the two light beams combined together by the probe-like polarizing prism PBS are linearly polarized lights orthogonal to each other and therefore, actually they do not intactly interfere with each other, and even if they are detected, they do not become light-and-shade signals. The two light beams reflected by the non-polarizing beam splitter NBS, when transmitted through the quarter wavelength plate QWP, the linearly polarized lights orthogonal to each other are converted into circularly polarized lights of opposite directions, and when the vibration surfaces of the two are vector-combined, they are converted into a rotating linearly polarized light by the fluctuation of the phase difference between the two.
[0038] This rotating linearly polarized light passes through the aforementioned opening AP, whereafter it is amplitude-splitted into four light beams (here, ±first-order diffracted lights created in each of two directions orthogonal to each other) by a phase diffraction grating having staggered grating structure (i.e., a phase diffraction grating having diffracting action in each of two directions orthogonal to each other). All of these light beams have their natures such as shape, intensity irregularity and defect entirely equally splitted by the amplitude division from the same area and therefore, even if for some reason or other, the interference fringes become not one color or are reduced in contrast, the influences thereof will all become equal. Particularly, the reflected light from the head arm side has its wavefront disturbed by minute uneven structure and has intensity irregularity created strongly, but the ways of disturbance of the wavefronts and the states of intensity irregularity of the four light beams become equal. The phase diffraction grating is designed to avoid the creation of O-order light to the utmost.
[0039] The light beams splitted into four are transmitted through polarizing plates (analyzers) disposed with their polarization azimuths deviated by 45° from each other, whereby it is converted into interference light in which the timing of light and shade deviates by 90° in terms of phase. The reductions in contrast by the influences of the disturbance of the wavefront and the intensity irregularity are all equally influenced. The light beams of light and shade are received by respective light receiving elements PD 1 , PD 2 , PD 3 and PD 4 .
[0040] The signals of the light receiving elements PD 1 and PD 2 having a phase difference of 180° therebetween are differentially detected, whereby a DC component (in which is contained a reduction in contrast or the like by the disturbance or the like of the wavefront) is substantially removed. This is an A phase signal. Likewise, the signals of the light receiving elements PD 3 and PD 4 having a phase difference of 180° therebetween are differentially detected, and a DC component is substantially removed. This is a B phase signal. The A and B phase signals have a phase difference of 90° therebetween, and the Lissajous waveform observed by an oscilloscope becomes circular. The amplitude of the Lissajous waveform (the size of the circle) fluctuates by the minute unevenness of the head arm side, but the central position thereof does not fluctuate. Consequently, no error is not essentially created in the phase detection (measurement of the relative distance). Specifically, these A and B phase signals have the value of their DC component O binarized as a threshold value by a binarizing circuit, not shown, but even if an amplitude fluctuation occurs to the original A and B phase signals, the DC component remains O and does not fluctuate and therefore, no fluctuation occurs to the phase of the binarized signal and consequently, by the use of this binarized signal of which the phase has been stabilized, highly accurate position detection can be executed by the signal processor SP 2 .
[0041] Also, by the light being condensed and illuminated on the head arm side, the influence of the fluctuation (one-color deviation) of the interference state by the relative angle deviation (alignment deviation) of the head arm side is avoided. That is, by being condensed and illuminated, even if there is alignment deviation, the main emergence azimuth of the divergent spherical wave only somewhat deviates and the eclipse of the spherical wave itself is avoided and also, the overlapping state of the wavefronts of two divergent spherical waves does not change and therefore, an interference state is stably obtained. Consequently, the present position detecting sensor operates as an interference type position detecting sensor which does not require the adjustment of the head arm side and the illuminating light beam and which is very easy to handle.
[0042] Also, although the illuminating position deviation (parallel deviation) is not concerned with the phase deviation of the divergent spherical wave, it becomes the fluctuation of the amplitude of the interference signal due to a change in the minute uneven state of the head arm conforming to the illuminating position. However, the central position of the Lissajous waveform does not fluctuate and therefore, no error is not essentially created in the phase detection.
[0043] The positional relation between the head arm and the position detecting sensor is such that both of them are rotatively moved about rotary shafts coaxial with each other and they do not deviate from each other as long as the distance between the two is kept constant. However, realistically there can be no completely coaxial shafts and therefore, by a shaft deviation error, there occurs a relative positional relation (angular deviation and parallel deviation) during the rotation of the two. However, as described above, no problem essentially arises even if alignment deviation or parallel deviation occurs.
[0044] The signal to finally be detected has its principles based on the interference measured length by the reciprocative optical path and therefore is a sine wave-like signal having a half of the wavelength of the light source as its period. When a laser diode of a wavelength 0.78 μm is used, there is obtained a sine wave signal having a period of 0.39 μm (i.e., a sine wave each time the spacing between the side of the head arm ARM 1 and the optical probe NCP varies by 0.39 μm), and the fluctuation of the relative distance can be detected by counting the wave number. Further, two phases (A and B phases) of sine wave signals having a phase difference of 90° therebetween are obtained in the aforedescribed manner and therefore, by counting the signals after electrically splitting the signal by a well known electrical phase splitting device, the relative position deviation of more minute resolving power can be detected. If the signal is electrically splitted into 4096 pieces, the relative position deviation can be detected up to minimum 0.095 mm.
[0045] The signal processor SP 2 supplies a control current to a head arm driving motor (voice coil) VCM through a motor driver VCMD so that the relative position deviation detected in this manner may become zero. By doing so, for example, by the above-mentioned wavelength, the position of the magnetic head arm ARM 1 relative to the optical probe NCP can be stably held (apply servo) at the order of several times as great as ±0.095 nm.
[0046] On the other hand, if use is made of a highly accurate rotary positioner RTP containing therein a rotary encoder RE producing a signal of 81000 sine waves/rotation as a specific numerical value, and capable of splitting it into 2048 and positioning them, an optical probe NCP as a position detecting sensor mounted near the side of the head arm having a radius of 30 mm can be positioned with resolving power several times as great as ±1.4 nm.
[0047] Since the stabilization of the relative position of the position detecting sensor itself is about several times as great as ±0.095 nm as described above, the positioning resolving power of the two as combined together is at the level of the performance of the highly accurate rotary positioner itself.
[0048] By adding the servo for keeping the relative position of the end surface of the head arm constant through the position detecting sensor to the highly accurate rotary positioner as described above, stable positioning accuracy can be provided without any disturbance such as the vibration as by the rotation of the hard disc transmitted to the highly accurate positioner through the head arm ARM 1 . As regards the writing-in of signals, the arm ARM 2 is rotated by the motor MO to thereby move the optical probe NCP while taking feedback control by the system of the rotary encoder RE, the signal processor SP and the motor driver MD, and the magnetic head arm ARM 1 is displaced by the system of the signal processor SP 2 , the motor driver VCMD and the head arm driving motor VCM so as to negate the displacement at this time, to thereby position the magnetic head arm while sequentially finely feeding it, and servo track signals from the signal generator SG are successively written in from the magnetic head.
[0049] The interference between the reflected light beam from the side of the head arm and the reflected light beam from the reference reflecting surface is obtained within the coherence distance of the light source. A single-mode laser diode has a long coherence distance, but may sometimes cause mode hop to give rise to a phenomenon that the interference phase hops and therefore, in the present embodiment, a multimode laser is used and the optical path lengths are made substantially equal, and the multimode laser is used at an optical path length difference less than the coherence distance. As a specific example of numerical values, the central wavelength λ0 of the light source is λ=780 nm, and the full width of a half value of the multimode spectrum envelope is Δλ=6 nm, and generally the full width of the coherence distance is given by splitting the square of λ0 by Δλ and therefore is about ±50 μm centering around the equal optical path length.
[0050] Also, the laser diode generally has its wavelength fluctuated by the fluctuation of the ambient temperature. Taking a laser diode of a central wavelength 780 nm and a temperature coefficient 0.66 nm/° C. as an example, when the optical path length difference ΔL is ΔL=50 μm, the deviation of a measured value by the temperature fluctuation of 1° C. is of the order of ±5 nm.
[0051] If the distance is kept constant near a coherent peak, the optical path length difference can be realized at ±10 μm and the measurement error in that case is ±1 nm. This value is sufficient accuracy as a servo track writer.
[0052] Also, a laser interference length measuring apparatus is not stable in its signal output due to fluctuation or the like when the optical paths thereof are generally separate and constructed while being exposed in the air. In the present embodiment, however, most of the interference optical path is a common optical path and is separated into two optical paths near the tip end of the probe-like polarizing prism, but is minute and in a glass medium and is constructed so that the influence of fluctuation or the like may become very small.
[0053] The main effects of the above-described Embodiment 1 will be mentioned below.
[0054] 1. Since the side of the head arm can be position-measured completely in non-contact, the resolving power, accuracy and stability of servo writing are improved.
[0055] 2. Since laser interference length measurement is the principle, resolving power and accuracy are very high.
[0056] 3. Since the minute uneven surface of the side of the head arm is directly measured, flexibility is high and any special optical element or the like need not be added to the hard disc side.
[0057] 4. Since the bad influence of the alignment deviation between the side of the head arm and the illuminating light beam upon the measuring system is small, the positioning adjustment accompanying mounting, dismounting and interchange is easy and the servo writing work onto the hard disc can be effected efficiently.
[0058] 5. Since an equal optical path length interference system is utilized, relatively high accuracy is ensured even under temperature fluctuation.
[0059] 6. Since most of the interference optical path is a common optical path and most of the optical path after splitted is in glass, the reduction in accuracy by environmental fluctuations is small.
[0060] [0060]FIG. 3 is an illustration of the construction of an optical system according to Embodiment 2 in which the probe-like polarizing prism has been changed in shape to cope with a case where the side of the head arm is proximate to the surface of the hard disc. In the other points, the construction of Embodiment 2 is similar to that of Embodiment 1 and therefore need not be shown and described.
[0061] In the present embodiment, a parallel glass plate G with reflecting film is joined to that portion of the probe-like polarizing prism PBS which is immediately behind the splitted surface thereof, and a P-polarized light beam transmitted through the splitted surface of the probe-like polarizing prism PBS is reflected by reflecting film M 1 , and is again transmitted through the polarizing film and impinges on partial reflecting film M 2 provided on the side of the optical probe NCP, and returns along the original optical path. An S-polarized light beam reflected by the splitted surface of the probe-like polarizing prism PBS goes out of the optical probe NCP as in the aforedescribed embodiment, and is condensed and illuminated on the side of the head arm ARM 1 , and the reflected light thereof returns along the original optical path.
[0062] By adopting this construction, the distance (see FIG. 2A) between the tip end of the optical probe NCP and the underside of the lowermost hard disc HD can be widened, and measurement also becomes possible on the side of a magnetic head arm of a type in which the magnetic head arm is proximate to the surface of the hard disc. It will be most effective if as shown in FIG. 3, the end portion of the parallel glass plate G is worked into 45°.
[0063] [0063]FIG. 4 schematically shows the construction of a servo track signal writing-in apparatus according to Embodiment 3 of the present invention. In FIG. 4, members similar to those in the aforedescribed embodiments are given the same reference characters. Although partly repeated, the present embodiment will hereinafter be described in detail.
[0064] A hard disc drive device HDD has mounted thereon a magnetic head arm ARM 1 having a rotary shaft O outside hard discs HD, and a slider SLID mounted on the tip end thereof is disposed with a gap of 0.5 μm (or less) in opposed relationship with the surface of the hard discs, and is arcuately moved by the rotation of the magnetic head arm ARM 1 . The rotation is effected by an electric current being supplied to a voice coil motor VCM.
[0065] Such an apparatus is disposed at a spatially proper position as shown in FIG. 4 relative to the hard disc drive device HDD comprising the hard discs HD, the slider SLID, the magnetic head arm ARM 1 , the voice coil motor VCM, etc.
[0066] SG designates a signal generator for generating servo track signals to be written into the hard discs, and the servo track signals are written into the hard discs HD through the magnetic head of the slider SLID.
[0067] A position detecting unit NCPU is provided on a support arm ARM 2 , and the tip end portion of an optical probe NCP is inserted in the slot-like opening (not shown) of the base plate of the hard disc drive device HDD and is disposed near the side of the magnetic head arm ARM 1 . The support arm ARM 2 is disposed so as to be rotatively movable by a rotary shaft coaxial with the center of rotation O of the magnetic head arm ARM 1 . The rotated position of the position detecting unit NCPU is detected by a high resolving power rotary encoder RE mounted on the rotary shaft of the support arm ARM 2 , and on the basis of this detection data, a signal processor SP 1 rotatively drives a motor MO through a motor driver MD. The position detecting sensor unit NCPU is rotatively positioned by this form of feedback control.
[0068] The position detecting unit NCPU is comprised of an optical type sensor unit as will hereinafter be described.
[0069] [0069]FIG. 5 is an illustration of the construction of an optical system for illustrating the optical type sensor unit. The optical type sensor unit is comprised of a multimode laser diode LD, a non-polarizing beam splitter NBS, a probe-like polarizing prism PBS, a probe holder PHD, a reference reflecting surface M, a quarter wavelength plate QWP, a light beam diameter limiting opening AP, a light beam amplitude splitting diffraction grating GBS, polarizing plates PP 1 -PP 4 , photoelectric elements PD 1 -PD 4 , etc.
[0070] Divergent light from the multimode laser diode LD is made into a loose condensed light beam BEAM by a collimator lens COL, and is transmitted through the non-polarizing beam splitter NBS and then impinges on the probe-like polarizing prism PBS of the optical probe NCP which is formed of a light transmitting substance, and is splitted into each polarized component by the light splitting surface of the probe-like polarizing prism PBS. A reflected S-polarized light beam is condensed and illuminated near the beam waist on the side of the head arm ARM 1 (here, the arm portion for the magnetic head for the underside of the lowermost hard disc) disposed in a space spaced apart by about 300 μm from the end surface of the probe-like polarizing prism PBS, and the reflected light becomes a divergent spherical wave and returns along the original optical path, and is returned to the light splitting surface of the probe-like polarizing prism PBS. A P-polarized light beam transmitted through the probe-like polarizing prism PBS is condensed and illuminated at a position deviating from the beam waist (a state short of the beam waist) on the reflecting deposited film of the end surface, and the reflected light returns along the original optical path and is returned to the light splitting surface of the probe-like polarizing prism PBS. The respective optical path lengths of the two optical paths are set so that the optical path length difference therebetween may be within the coherence distance of the light source, that is, the optical path lengths may be substantially equal to each other.
[0071] Specifically, for example, the shape is given as follows. The width of the probe-like polarizing prism PBS formed of glass is of the order of 2 mm, and the light beam reflected by the polarizing prism PBS travels by 1 mm through the glass and travels by 0.3 mm through the air, and is illuminated on the head arm side ARM 1 . Consequently, the reciprocative wave motion optical path length L1 from the polarizing prism to the reflecting surface is L1=(1×1.5+0.3)×2=3.6. On the other hand, the light beam transmitted through the polarizing prism PBS travels by 1.2 mm through the glass, and is illuminated on the end surface of the glass. Consequently, the reciprocative wave motion optical path length L2 is L2=(1.2×1.5)×2=3.6. So, the refractive index of the glass was 1.5.
[0072] Next, the condensed position (beam waist) of the light beam is set to a position of 0.3 mm after the light beam has emerged from the polarizing prism. Thereupon, the position of the wave source of a divergent spherical wave reflected from the head arm side and the reference reflecting surface looks deviated in the direction of the optical axis. Assuming that the interior of the probe-like polarizing prism is looked into from the light source side, the condensing point (wave source) on the head arm side is seen at a position of L1′=(1+0.3×1.5)=1.45 from the splitting surface of the polarizing prism. The position of the divergent spherical wave source from the reference reflecting surface is seen at a position of L2′=1.2×2−1.45=0.95 from the splitting surface of the polarizing prism. However, the both positions are positions seen in the glass. Consequently, the two divergent spherical wave sources deviate by 0.5 mm from each other in the glass (an imaging optical path length difference is created), and when the two light beams are superposed one upon the other, the wavefronts do not completely coincide with each other, and if the two polarized lights are put together, there will be obtained concentric circular interference fringes. In that case, when the phases of the wavefronts of the two are fluctuated by the relative movement of the head arm, the concentric circular interference fringes look gushing out of or inhaled into the center. However, as regards these concentric circular interference fringes, an interference fringe portion of substantially one color (the same phase) is widely obtained because the amount of deviation between the two divergent spherical waves in the direction of the optical axis is as small as about 0.5 mm. Consequently, an appropriate opening AP is provided so as to take out only the substantially one color portion to thereby take out some of the light beam. Thereafter, it can be handled as a substantially plane wave.
[0073] Now, the two light beams combined together by the probe-like polarizing prism PBS are linearly polarized lights orthogonal to each other and therefore, actually they do not intactly interfere with each other, and even if they are detected, they do not become light and shade signals. The two light beams reflected by the non-polarizing beam splitter NBS, when transmitted through the quarter wavelength plate QWP, are converted from linearly polarized lights orthogonal to each other into circularly polarized lights of opposite directions, and when the vibration surfaces of the two are vector-combined, they are converted into a linearly polarized light rotated by the fluctuation of the phase difference between the two.
[0074] This rotated linearly polarized light passes through the aforementioned opening AP, whereafter it is amplitude-splitted into four light beams (here, ±first-order diffracted lights created in each of two directions orthogonal to each other) by a phase diffraction grating having staggered grating structure (i.e., a phase diffraction grating having diffracting action in each of two directions orthogonal to each other). By the amplitude division from the same area, any of the light beams is splitted entirely equally in its natures such as shape, intensity irregularity and defect and therefore, even if the interference fringes become not one color or are reduced in contrast for some reason or other, the influences thereof all become equal. Particularly, the reflected light from the head arm side has its wavefront disturbed by minute uneven structure and intensity irregularity occurs strongly, but the ways of disturbance and the states of intensity irregularity of the wavefronts of the four light beams are equal. The phase diffraction grating is designed to avoid the creation of 0-order light to the utmost at the same time.
[0075] The light beams splitted into four are transmitted through polarizing plates (analyzers) having their polarization azimuths disposed with a deviation of 45° with respect to one another, whereby it is converted into interference lights in which the timing of light and shade deviates by 90° in terms of phase. The reductions in contrast by the influences of the disturbance of the wavefront and the intensity irregularity are all equally influenced. The respective light and shade light beams are received by the respective light receiving elements PD 1 , PD 2 , PD 3 and PD 4 .
[0076] The signals of the light receiving elements PD 1 and PD 2 having a phase difference of 180° therebetween are differentially detected, whereby a DC component (including a contrast reduction by the disturbance or the like of the wavefront) is substantially eliminated. This is an A phase signal. Likewise, the signals of the light receiving elements PD 3 and PD 4 having a phase difference of 180° therebetween are differentially detected, whereby a DC component is substantially removed. This is a B phase signal. The A and B phase signals have a phase difference of 90° therebetween, and the Lissajous waveform observed by means of an oscilloscope becomes circular. The amplitude of the Lissajous waveform (the size of the circle) is fluctuated by the minute unevenness of the head arm side, but its central position is not fluctuated. Consequently, essentially no error occurs to the phase detection (the measurement of the relative distance). Specifically, these A and B phase signals have the value of their DC component 0 binarized as a threshold level by a binarizing circuit, not shown, but even if an amplitude fluctuation occurs to the original A and B phase signals, the DC component remains 0 and is not fluctuated and therefore, no fluctuation occurs to the phase of the binarized signal and consequently, by the use of this binarized signal stable in phase, highly accurate position detection can be executed by the signal processor SP 2 .
[0077] Also, the light is condensed and illuminated on the head arm side to thereby avoid the influence of the fluctuation (one-color deviation) of the interference state by the relative angle deviation (alignment deviation) of the head arm side. That is, by the light being condensed and illuminated, even if there is alignment deviation, the main emergence azimuth of the divergent spherical wave only somewhat deviates and the eclipse of the spherical wave itself is avoided, and also the overlapping state of the wavefronts of the two divergent spherical waves does not change and therefore, the interference state is obtained stably. Consequently, the sensor operates as an interference type position detecting sensor in which the adjustment of the head arm side and the illuminating light beam is unnecessary and which is very easy to handle.
[0078] Also, the illuminating position deviation (parallel deviation) is not concerned in the phase deviation of the divergent spherical wave, but becomes the fluctuation of the interference signal amplitude due to a minute change in the uneven state of the head arm conforming to the illuminating position. However, the central position of the Lissajous waveform does not fluctuate and therefore, essentially no error occurs to the phase detection.
[0079] The positional relation between the head arm and the position detecting sensor does not deviate as long as they are rotatively moved about the rotational axes thereof coaxial with each other and the distance between the two is kept constant. Realistically, however, the two axes cannot be completely coaxial with each other and therefore, due to an axis deviation error, the relative positional relation causes angular deviation and parallel deviation when the two are being rotated. However, as described above, essentially no problem will arise even if alignment deviation and parallel deviation occur.
[0080] The finally detected signal has its principle based on the interference measured length by the reciprocative optical path and therefore is a sine wave-like signal having a half of the wavelength of the light source as its period. When a laser diode of a wavelength 0.78 μm is used, there is obtained a sine wave signal having a period of 0.39 μm (i.e., a sine wave each time the spacing between the side of the head arm ARM 1 and the optical probe NCP changes by 0.39 μm), and by counting the wave number, the fluctuation of the relative distance can be detected. Further, sine wave signals having a phase difference of 90° therebetween are obtained in two phases (A and B phases) in the aforedescribed manner and therefore, by electrically splitting the signals by a well known electrical phase splitting device and thereafter counting them, relative positional deviation of finer resolving power can be detected. If the signals are electrically splitted into 4096 pieces, the relative positional deviation can be detected up to minimum 0.095 nm.
[0081] The signal processor SP 2 supplies a control current to the head arm driving motor (voice coil) VCM through the motor driver VCMD so that the relative positional deviation detected in this manner may become zero. By doing so, for example, in the above-mentioned wavelength, the position of the magnetic head arm ARM 1 relative to the optical probe NCP can be held (servo can be applied) stably at about several times as great as ±0.095 nm.
[0082] On the other hand, if use is made of a highly accurate rotary positioner RTP containing therein a rotary encoder RE producing a signal of 8100 sine waves/rotation as a specific numerical value and capable of splitting it into 2048 and positioning them, the optical probe NCP as a position detecting sensor mounted near the head arm side of a radius 30 mm can be positioned with resolving power several times as great as ±1.4 nm.
[0083] The stabilization of the relative position of the position detecting sensor itself is at about several times as great as ±0.095 nm as described above and therefore, the positioning resolving power resulting from the two having been put together becomes about equal to the performance of the highly accurate rotary positioner itself.
[0084] By servo for keeping the relative position of the end surface of the head arm constant being added to the highly accurate rotary positioner through the position detecting sensor, as described above, stable positioning accuracy can be obtained without any disturbance such as the vibration by the rotation or the like of the hard disc being transmitted to the highly accurate positioner through the head arm ARM 1 . The writing-in of signals is done by rotating the arm ARM 2 by the motor MO to thereby move the optical probe NCP while taking feedback control by the system of the rotary encoder RE, the signal processor SP and the motor driver MD, and displacing the magnetic head arm ARM 1 by the system of the signal processor SP 2 , the motor driver VCMD and the head arm driving motor VCM so as to negate the displacement at this time to thereby position the magnetic head arm while sequentially minutely feeding it, and writing the servo track signals from the signal generator SG in succession by the magnetic head.
[0085] The interference between the reflected light beam from the head arm side and the reflected light beam from the reference reflecting surface is obtained within the coherence distance of the light source. A single mode laser diode has a long coherence distance but may cause mode hop and in some cases, the phenomenon of the interference phase thereof flying may happen and therefore, in the present embodiment, a multimode laser is used to make the optical path lengths substantially equal, and is used at an optical path length difference less than the coherence distance. As a specific example of numerical values, assuming that the central wavelength λ0 of the light source is ζ0=780 nm and the multimode spectrum envelope half value full width is Δλ=6 nm, generally the full width of the coherence distance is given by the square of λ0 having been splitted by Δλ and therefore, is about ±50 μm centering around the equal optical path lengths.
[0086] Also, the laser diode is generally fluctuated in wavelength by the fluctuation of the ambient temperature. Taking a laser diode having a central wavelength 780 nm and a temperature coefficient 0.06 nm/° C. as an example, when the optical path length difference is ΔL=50 μm, the deviation of the measured value by a temperature fluctuation of 1° C. is of the order of ±5 nm.
[0087] If the distance is kept constant near the peak of coherency, an optical path length difference of ±10 μm can be realized, and the measurement error in that case is ±1 nm. This value is sufficient accuracy as a servo track writer.
[0088] Also, when a laser interference length measuring apparatus is generally constructed with optical paths separated and exposed in the air, the signal output thereof is not stable due to fluctuation or the like. In the present embodiment, however, most of the interference optical paths is a common optical path, and although the common optical path is separated into two optical paths near the tip end of the probe-like polarizing prism, it is minute and within a glass medium, and design is made such that the influence of fluctuation or the like becomes very small.
[0089] Here, the probe-like polarizing prism PBS is joined to a probe holder PHD and is fixed onto the rotary positioner arm ARM 2 with the position detecting device body.
[0090] The probe holder PHD is inserted in a portion of a cylindrical metallic member which is hollowed, and is adhesively secured in such a manner that the parallelopiped-like polarizing prism PBS is sandwiched from its opposite sides by a structure of a D-shaped cross-section. A hole extends like a tunnel through a portion of the pedestal of the probe holder PHD through which the light passes. The light beam emergence side end surface of the member of the substantially D-shaped cross-section of the probe holder PHD is so shaped and disposed as to fly out of the light beam emergence surface of the polarizing prism PBS by the order of 100 μm as a specific example of numerical value.
[0091] When as previously described, the spacing between the light beam emergence surface of the polarizing prism PBS and the side of the head arm ARM 1 satisfies the range of the order of 0.3 mm±0.05, a periodic signal of ½ of the wavelength of the light source is obtained in conformity with that spacing, but when the position detecting device and the head arm are disposed in a space at first, the relative positional relation therebetween is indefinite, and the distance between the light beam emergence surface of the polarizing prism PBS and the side of the head arm ARM 1 must be set by some means so as to satisfy the range of the order of 0.3 mm±0.05. At that time, a case where the two contact with each other is also supposed. However, by adopting the probe holder PHD of holding guide structure like that of the present embodiment, the probe-like polarizing prism PBS itself which is an optical member can be prevented from contacting and being damaged and creating positional deviation.
[0092] Also, the probe holder can be made very small and therefore can be made into a size equal to that of the push rod (PROD) of the servo track signal writing-in apparatus of the conventional art push rod type.
[0093] The main effects of the above-described Embodiment 3 will be mentioned below.
[0094] 1. The head arm side can be position-measured completely in non-contact, and even if the head arm side should contact, the optical member does not contact and is not damaged and therefore, the resolving power, accuracy, stability and safety of servo writing are improved. Particularly, when the head arm side contacts, it contacts at its two D-shaped end portions and therefore, the strength thereof can be kept. Also, the glass polarizing prism PBS is held from its opposite sides through an adhesive agent and therefore, even if stress such as heat or vibration is applied thereto, it is difficult for such a force that will bend the glass polarizing prism to act, and safety is ensured.
[0095] 2. The laser interference length measurement is the principle and therefore, the resolving power and accuracy are very high.
[0096] 3. The minute uneven surface of the head arm side is directly measured and therefore, flexibility is high and any special optical element or the like need not be added to the hard disc side.
[0097] 4. The bad influence of the alignment deviation between the head arm side and the illuminating light beam upon the measuring system is small and therefore, positioning adjustment accompanying mounting, dismounting and interchange is easy, and the servo writing work onto the hard disc can be effected efficiently.
[0098] 5. The equal optical path length interference system is utilized and therefore, relatively high accuracy is ensured even under temperature fluctuations.
[0099] 6. Most of the interference optical paths is a common optical path and most of the optical paths after splitted is within glass and therefore, the reduction in accuracy by environmental fluctuations is small.
[0100] [0100]FIG. 6 is an illustration of the construction of an optical system according to Embodiment 4 in which the probe-like polarizing prism holder PHD has been changed in shape. In the other points, the construction of this embodiment is similar to that of the aforedescribed Embodiment 1 and therefore need not be shown and described.
[0101] In the present embodiment, the D-shaped holding portions are singularized and the contacting portion is made into a cylindrical surface. By adopting such construction, even if there is more or less alignment deviation between the optical probe-like polarizing prism holder PHD and the surface of the hard disc HD, the contact position will become constant and the reproducibility of the initial position can be made splendid.
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This specification discloses an apparatus comprising a first system for forming a composite light beam of two light beams to be made to interfere with each other, a splitting member for amplitude-splitting the composite light beam into three or more splitted light beams in the same area, and a second system for obtaining interference light beams of different phases from the plurality of splitted light beams. The specification also discloses an apparatus for effecting information recording on a hard disc drive device comprising an optical system for splitting a light beam into two light beams, causing one of the two light beams to be condensed and reflected by the side of an arm for a recording reading head in the hard disc drive device, and superposing the condensed and reflected light beam on the other light beam to thereby obtain a composite light beam, a splitting member for amplitude-splitting the composite light beam into three or more splitted light beams in the same area, an optical member for obtaining interference light beams of different phases from the plurality of splitted light beams, light receiving elements for detecting respective ones of the interference light beams of different phases, a control system for effecting the positioning of the arm on the basis of the result of the detection by each of the light receiving elements, and signal writing-in means for writing a signal into a hard disc through the recording reading head each time the arm is positioned.
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BACKGROUND OF THE INVENTION
This invention relates to a system and apparatus for pumping liquids according to a predetermined volumetric ratio, and particularly to a system for the pumping of viscous liquids at predetermined fluid flow ratios.
The pumping of liquids according to predetermined and relatively precise ratios has long been a requirement in industry, particularly in fields where two or more liquid components are blended according to predetermined ratio requirements, such as might be the case in the proper mixing of a paint colorant component with a paint base material. In recent years the popularity of epoxies and other materials having an active catalyst component and a base component, each of which is inert when separate but highly reactive when mixed together, has imposed new requirements on proportioning systems. Such materials require careful separation of the individual components to avoid premature curing and other adverse effects prior to the time when they are to be used. Such components are typically completely separately handled by physically separate and individual pumping systems and are delivered to a common delivery point where they are practically simultaneously mixed together and applied to the finished product. Fast curing times require fast application of the mixed material, and the reactive nature of the mixed material requires transfer of the individual components in separate form to as near the point of application as possible.
A common approach to the proportioning of such liquids has been by the use of metering cylinders sized to the proper ratio requirements, and by common coupling the pistons in such metering cylinders to a single drive source, wherein reciprocation of the drive source causes identical reciprocation of the respective metering pistons, the ultimate liquid ratio being delivered thereby being dependent upon difference in internal volume of the metering cylinders.
Another approach to proportional metering utilizing a single drive source is disclosed in U.S. Pat. No. 3,967,634, issued July 6, 1976 and owned by the assignee of the present invention. This patent discloses a reciprocating drive motor coupled to a plurality of metering cylinders through variable lever arms, wherein the stroke of the drive source causes a measured and predetermined stroke of each of the metering cylinders thereby providing different volumetric flow rates depending upon stroke adjustment.
Another approach to metering liquids is disclosed in U.S. Pat. No. 3,107,034, issued Oct. 15, 1963, wherein reciprocating hydraulic pumps are driven by pressurized hydraulic oil provided by an electric motor and pump combination. The pressurized hydraulic oil is selectively valved into each of the hydraulic pumps, thereby controlling the speed of reciprocation of the respective pumps and consequently controlling the rate of flow of the pumped material. Such a system requires the use of bypass valves and other safeguards to prevent burnout of the electric drive motor under conditions wherein the pumps are in a "stalled" delivery mode, such as where back pressure develops in the flow lines, which back pressure is developed all the way back to the electric drive motor, which inherently attempts to provide hydraulic oil at a predetermined flow rate.
U.S. Pat. Nos. 4,019,652 and 4,170,319 issued Apr. 26, 1977 and Oct. 9, 1979 respectively, disclose fluid ratio delivery system utilizing pressurized accumulators for storing the respective fluid components, and appropriate valving into a common mixing chamber wherein the characteristics of the fluid components, the size of the input ports to the mixing chamber, and the predetermined fluid pressures are all selected so that the ratio of the flow rates by weight of the liquids at the input ports is constant. Such a system may be utilized for mixing a shot or small predetermined volume of at least two fluid components on an intermittent basis.
In any liquid proportioning and pumping system wherein reactive material components are mixed and applied, it is desirable to maintain physical separation between individual components prior to mixing. Further, in any system wherein such components are intermittently applied, as by way of a paint spray gun, it is necessary that the system accommodate the "blocked pressure" condition wherein the spray gun or applicator is shut off. In this situation back pressure is developed within the system which must be relieved or compensated for so that the motive driving force does not become damaged under a "stall" condition. Obviously, when electric motors or other similar motive drive forces are used, electrical disconnecting circuits must be provided to shut off the motor under "stall" conditions. Since air-operated drive motors have inherent ability to operate under "stall" conditions it is desirable to use such motors in applications of this type where possible.
SUMMARY OF THE INVENTION
The invention includes two or more reciprocable pumps for pumping respective liquid components, the pumps being mechanically driven by hydraulic reciprocating motors; the hydraulic motors are driven by pressurized hydraulic oil provided from respective metering cylinders, which cylinders are driven by common connection to a reciprocating air motor. Air pressure applied to the air motor causes the hydraulic metering cylinders to develop a predetermined flow rate of hydraulic oil to the hydraulic motors; the flow rate being determined by the relative size ratios of the metering cylinders, and the rate of reciprocation of the hydraulic motors being determined by the flow rate of hydraulic oil applied thereto. The respective liquid components pumped by the system will therefore be delivered according to the same ratio as the metering cylinders utilized to drive the hydraulic motors.
It is therefore a principal object of the present invention to provide a system for regulating the pumping rate of two or more pumps by means of regulating the ratio flow rate of the respective pump driving liquid.
It is another object of the present invention to provide a ratio-control liquid pumping system having the inherent capability of operating under "stall" conditions.
It is a further object of the present invention to provide a proportioning system wherein the proportioned liquid components may be maintained at a physical separation with respect to one another.
BRIEF DESCRIPTION OF THE DRAWING
The foregoing and other objects will become apparent from the appended specification, and with reference to the attached drawing in which a symbolic and schematic diagram of the invention is shown.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to the drawing, there is shown in symbolic and schematic form a pumping system 10 which embodies the features of the present invention. A first container 12 holds a viscous material such as a first paint component, and a second container 14 holds a second material such as a second paint component. A reciprocable pump 13 is immersed into the liquid within container 12, and pump 13 may be operated to pump the liquid through outlet pipe 16 in the direction shown by the arrows. Similarly, a reciprocable pump 15 is immersed in the liquid held by container 14 and pump 15 may be operated to pump the liquid through outlet pipe 18 in the direction of the arrows. The liquid in pipe 16 is conveyed through a valve 20 to a manifold 25, and the liquid in pipe 18 is conveyed through a valve 22 to manifold 25. Valves 20 and 22 may be simultaneously operated by means of lever 21 so as to simultaneously fill manifold 25 with liquid components from outlet pipes 16 and 18. A mixer 24 is connected downstream of manifold 25, and is constructed in a manner to thoroughly mix the liquid components as they flow through the mixer. A hose 26 is connected to the outlet of mixer 24 to convey the mixed liquids to a delivery device or applicator such as a spray gun (not shown).
Pump 13 is driven by a reciprocable hydraulic motor 27, which receives pressurized hydraulic oil through intake line 32 and exhausts hydraulic oil through exhaust line 34 in the directions of the arrows as shown. Similarly, pump 15 is operated by means of a reciprocable hydraulic motor 29, receiving pressurized hydraulic oil input via intake line 36 and exhausting hydraulic oil through exhaust line 38 in the directions shown by the arrows. The hydraulic motor/pump assemblies are commercially obtainable components, as for example hydraulic motors 27 and 29 may be the "Viscount" model manufactured by the assignee of the present invention under Part No. 208-270. Likewise, pumps 13 and 15 may be a type manufactured by the assignee of the present invention as Part No. 946-203, which in combination with the aforementioned hydraulic motor develops a pumping pressure to inlet oil pressure amplification of 1.79:1.
An oil reservoir 30 receives the exhaust oil from pipes 34 and 38, and provides a supply of oil for feed pipe 40. Feed pipe 40 is connected to a manifold 42 which has inlet connections to metering cylinders 44 and 46. A reciprocable piston within cylinder 44 is connected to rod 45; a reciprocable piston within cylinder 46 is connected to rod 47. Rods 45 and 47 are connected to shaft 48 by means of arm 49. Shaft 48 forms a part of air motor 50, which is reciprocable upon application of air pressure via inlet air line 52. A regulator 54 may be used to provide controllable inlet air pressure. Air motor 50 has an air exhaust (not shown) and an internal valving system which permits air pressure to reciprocate shaft 48. Air motor 50 is a commercially obtainable device, such as the "Hydra-Cat" model manufactured by the assignee of the present invention under Part No. 208-851. Metering cylinders 44 and 46 are also commercially available, and may be selected to provide the desired pumping ratios from pumps 13 and 15. For example, if the ratio of liquid to be pumped from pumps 13 and 15 is 1:2, cylinder 44 is chosen to have an internal cross-sectional area equal to 1/2 the cross-sectional area of cylinder 46. Of course, further control and variation of the ratios of liquid pumped by pumps 13 and 15 may be had by varying the respective sizes of pumps 13 and 15 in addition to varying the sizes of metering cylinders 44 and 46. For example if pump 13 is chosen to have a pumping capacity flow rate of 1/3 the capacity of pump 15, and metering cylinders 44 and 46 are further selected in the ratio of 1:2, the material delivered via outlet pipes 16 and 18 will flow in the ratio 1:6.
Container 12, with its associated pump and drive motor, may be remotely located from container 14, its associated pump and drive motor, and also from air motor 50 and its associated equipment. This is possible because the only lines interconnecting the respective components are pressurized hydraulic oil lines, which may be extended over considerable distances. Likewise, air motor 50 and its associated equipment may be physically separated from either or both pumps 13 and 15, as well as from the application hardware consisting of valves 20, 22, manifold 25 and mixer 24.
In operation, air pressure is applied to air motor 50 to cause it to begin reciprocation, thereby reciprocating rods 45 and 47 in metering cylinders 44 and 46. During the upstroke of rods 45 and 47 hydraulic oil is drawn into metering cylinders 44 and 46 via intake manifold 42, and is also pumped outwardly via pipes 32 and 36. During the downstroke of rods 45 and 47 the oil previously admitted into cylinders 44 and 46 is pumped outwardly via pipes 32 and 36. Thus, a continuous supply of pressurized hydraulic oil is provided via pipes 32 and 36, the volume flow rate being dependent upon the volumetric pumping capacities of the respective metering cylinders. The pressurized hydraulic oil pumped to the respective hydraulic motors 27 and 29 causes reciprocation thereof, and mechanical interconnection with pumps 13 and 15 causes a corresponding reciprocation in the pumps. Pumps 13 and 15 are designed to deliver liquid through lines 16 and 18 during both the upstroke and downstroke portion of their respective cycles, and thereby a continuous supply of liquid is provided to manifold 25 when valves 20 and 22 are opened. The liquid in manifold 25 passes into mixer 24 and becomes thoroughly mixed, and then passes through hose 26 to the applicator device, which may be a spray gun.
In the event valves 20 and 22 are turned off, or in the event the applicator itself is turned off, a liquid back pressure immediately develops in line 16 and 18. This back pressure is sensed by the respective hydraulic motors which develop corresponding back pressures in their inlet lines 32 and 36. The build-up of pressure in lines 32 and 36 is passed back into the metering cylinders 44 and 46, resulting in a back pressure to resist the reciprocating driving force of rods 45 and 47. When this back pressure builds up to a value sufficient to balance the applied air pressure at inlet 52, air motor 50 stalls and ceases its reciprocating action. It will remain in this condition until pressure at the outlet is again relieved, at which time air motor again begins its reciprocating action. The stalled condition of air motor 50 merely indicates a balancing of pressure forces across the air motor drive piston, and requires no special safeguards to protect against damage of the air motor in this condition.
The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and it is therefore desired that the present embodiment be considered in all respects as illustrative and not restrictive, reference being made to the appended claims rather than to the foregoing description to indicate the scope of the invention.
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A system for pumping liquid materials with reciprocating pumps driven by hydraulically operated motors, wherein the pressurized hydraulic oil which is used to drive the hydraulic motors is supplied via reciprocating proportioners. The reciprocating proportioners are driven by a reciprocating air motor operated under predetermined air pressure. The system operation is characterized in that, under blocked output pressure conditions, the air motor will inherently stall and thereby limit the pressure of the hydraulic oil acting to drive the hydraulic motors, which therefore limits the pumping pressure applied to the reciprocating pumps, and limits the output pressure of the pumped liquid materials.
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This is a continuation-in-part of application Ser. No. 63,302, filed Aug. 2, 1979, now abandoned.
FIELD OF THE INVENTION
The present invention relates to processes for the preparation of certain halogenated aliphatic ethers. More particularly, the present invention relates to the preparation of such halogenated ethers from certain perhalogenated alkanes.
BACKGROUND OF THE INVENTION
One commercial process for the manufacture of 1,1,2-trifluoro-2-chloroethyl methyl ether is a two-step process, as follows: ##STR1##
The first step in this process is expensive because it involves the preparation of the gas CF 2 ═CFCl, which must be distilled under pressure or at low temperature. The solvent methanol must be recovered from the by-product zinc chloride, and disposal of the zinc chloride is a problem.
The second step of this synthesis is efficient, but requires a separate reactor and purification system.
The reaction of certain perhalogenated alkanes with a primary or secondary alkanol and an inorganic base to produce certain halogenated ethers is described in Corley et al, JACS 78, on p. 3491, bottom of col. 1, as follows:
CF.sub.2 ClCFCl.sub.2 +KOH+CH.sub.3 OH→CH.sub.3 OCF.sub.2 CHFCl
The text of this article indicates a reaction at 125° for 20 hours, and then:
"The product was taken up in diethyl ether, washed with water, dried and fractionated through a 30-plate column to give a 30% yield (range 20-36%) of CH 3 OCF 2 CHFCl . . . "
The results obtained by Corley, in a reaction without a catalyst, generally showed low yields and conversions, and relatively long reaction times.
An article by Scipioni et al, Ann. Chem. Rome, 1967, 57(7), pgs. 817-824, also discusses the reactivity of various halogenated alkanes with alkanols and inorganic bases to product ethers therefrom.
In Fluorine Chemistry Reviews, by Metille and Burton, p. 354, the authors describe the dehalogenation of CF 3 I to CF 3 H, using KOH in a solvent of high dielectric constant, specifically referred to ethanol. The use of the reaction to dehalogenate CF 3 CF 2 I to CF 3 CF 2 H is also discussed.
The source article referred to by Metille and Burton is Banus et al., J. Chem. Soc. 1951, pp. 60-64. This publication states that it is known that the C-I bond in CF 3 I can undergo homolytic fission but that, apart from decomposition, CF 3 Cl, CF 2 Cl 2 and CHF 2 Cl "do not show reactions involving the homolytic or heterolytic fission of the carbon-chloride bond". The publication in general stresses that the iodo compounds are unique as compared to the corresponding bromo or chloro compounds. It would not, therefore, suggest the use of the same type of reaction even for brominated, chlorinated, or fluorinated alkanes, let alone ethers.
Dittman, 2,636,908 relates to dehydrochlorination in the presence of caustic or KOH, to produce CF 2 ═CClF. Alcohol was not used. Other references to dehydrohalogenation may be found in Frederick, U.S. Pat. No. 2,709,181; Young, U.S. Pat. No. 3,391,204, Ex. 15; Miller, U.S. Pat. Nos. 2,803,665 and 2,803,666; Tarrant et al, JACS 76, 2343 at 2344 (1954) and Corley et al, supra at 3489 (1956).
One addition of an alcohol to an olefinically unsaturated perhaloethylene is described in Corley et al, supra, 78 JACS at 3491, where the following reaction is described:
CF.sub.2 ═CFCl+KOH+CH.sub.3 OH→CH.sub.3 OCF.sub.2 CHFCl
Park et al, in JACS 70, 1550 (1948), describe the addition of methanol and ethanol to CF 2 ═CFCl. Hanford, U.S. Pat. No. 2,409,274 describes an addition reaction of an unsaturated substrate with an alcohol in the presence of a base, to produce an ether, as follows:
CF.sub.2 ═CF.sub.2 +NaOEt+EtOH→CF.sub.2 HCF.sub.2 OC.sub.2 H.sub.5
Another description of a similar alcohol addition reaction appears in Aliphatic Fluorine Compounds, Lovelace et al., Reinhold, 1958, pp. 155-159.
The Lovelace et al text, supra, describes the reaction between fluorocarbon halides and alcoholates as generally producing ethers, citing several examples. The Tarrant and Young work, JACS 75, 932 (1953), is relied upon by Lovelace et al as establishing that the general reaction is not a simple Williamson synthesis.
Young, U.S. Pat. No. 3,391,204 describes the reaction between a perhalogenated fluoro-chloro-substituted alkane and TEA (Ex. 11), which may be in the presence of CuCl 2 (Ex. 12; Col. 7, 11, 6-25) and methanol (Col. 6, 1. 74) or other alkanol (Col. 6, 11, 68-69). The alcohol or other solvent is considered to be an inert diluent (Col. 6, 11, 28, et seq.). Generally, the reaction extracts a chlorine and replaces it with a hydrogen, as in Exs. 7, 8, 11 and 12, but the reaction may go one step further with a dehydrohalogenation step occurring (Exs. 7, 8 and 15) with the production of an ethylenically unsaturated product. Young's reactions do not produce ethers.
Park et al report in JACS 70, at 1550, that:
"Alkyl ethers containing fluorine were previously prepared by Swartz by the action of alcoholic caustic or metallic carbonate on polyfluorohaloethanes. This procedure was later modified by Gowland."
The Gowland reference is to British Pat. No. 523,449, which describes the following reaction:
CHCl.sub.2 CF.sub.2 Cl+KOH+ROH→CHCl.sub.2 CF.sub.2 OR+KCl+H.sub.2 O
Gowland's initial reaction is not perhalogenated.
Other reactions are known in which a halogenated alkane is reacted with an alcohol and an inorganic base, to produce a halogenated ether, but the halogenated alkane is not a perhalogenated compound, as in the present invention, and the reaction mechanism is that of dehydrohalogenation, rather than reduction. These include U.S. Pat. No. 3,637,477, granted Jan. 25, 1972, to L. S. Croix, and assigned to Air Reduction Co., Inc.; and J. Gen. Chem. (U.S.S.R.), 29, 1113-1117 (1959), Soborovskii and Baina, Difluorochloromethane as a Difluoromethylating Agent.
The presence of hydrogen substituents in the halogenated alkane, and its chain length, also affect the reaction. Thus, Tarrant et al, JACS 76, at p. 2344, state:
" . . . CH 2 CLCH(CH 3 )CH═CF 2 . . . is the product which would be expected from CH 2 ClCH(CH 3 )CH 2 CF 2 Cl, since it has been shown that the point of attack by a base on molecule containing fluorine is the hydrogen on a carbon adjacent to a cluster of fluorine atoms on a single atom."
with a citation to Tarrant and Young, JACS 75, 932 (1953).
U.S. Pat. No. 3,931,238 to Starks discloses the preparation of various alcohols and ethers from halogenated hydrocarbons. In particular, this patentee employs various betaines as catalysts in connection with aqueous alkali metal hydroxide solutions. This patentee does not employ any primary or secondary alkanol reactants, however, and among the betaines includes certain quaternary ammonium salts. No primary, secondary or tertiary amines are said to be useful as catalysts therein. As a matter of fact, this patentee specifically shows in Example 1 that one tertiary amine is comparatively highly inferior to his betaines and excluded from his invention.
Finally, U.S. Pat. No. 2,332,467 to Linn et al relates to the production of mixed ethers by contacting an alcohol with an alkyl halide and zinc at elevated temperatures.
SUMMARY OF THE INVENTION
In accordance with the present invention it has now been discovered that in the reaction of certain perhalogenated alkanes (preferably ethanes) such as CF 2 ClCFCl 2 (Freon 113) with a primary or secondary alkanol (ROH) and an inorganic base, for the production of particular ethers, the reaction can be greatly improved, for example over that disclosed in the aforementioned Corley article, by the use of a particular type of catalyst, in terms of improved reaction times, better yields, higher conversions, lower operating temperatures, etc. Also, the reaction may be advantageously carried out with these results being obtained at atmospheric pressure.
The particular type of catalyst system in question includes (1) certain specific varivalent metal-containing catalysts. In particular, such catalysts thus include either copper in its metallic (elementary) form, preferably in a finely divided metallic state, or the following metals in the form of their corresponding metal salts; copper, silver, cobalt, rubidium, aluminum, manganese, nickel, iron, molybdenum, chromium, antimony, and vanadium, and/or (2) the primary, secondary and tertiary amines.
The present invention is limited to certain specific perhalogenated alkanes which are useful in this reaction.
First, these compounds must have at least one carbon with the configuration CXF 2 , where X═Cl or Br. Thus, the perhalogenated ethane may be represented as:
CXF.sub.2 CY.sub.3
Since CXF 2 is not reduced, CY 3 must be a reducible group where at least two of the Y's must be Br or Cl. Thus, the general formula for suitable perhalogenated ethanes for use in the reaction of the invention is:
CXF.sub.2 CY.sub.2 Z
where
X=Br or Cl
Y=Br or Cl
Z=Br, Cl or F.
Using this description, there are 14 suitable perhalogenated ethanes, which can be reacted according to the invention to produce ethers, as follows:
______________________________________Starting Perhalogenated Ethane Ether Product______________________________________1. CF.sub.2 ClCCl.sub.2 F RO--CF.sub.2 CHFCl2. CF.sub.2 ClCBr.sub.2 F RO--CF.sub.2 CHFBr3. CF.sub.2 ClCBrClF RO--CF.sub.2 CHFCl4. CF.sub.2 ClCCl.sub.3 RO--CF.sub.2 CCl.sub.2 H5. CF.sub.2 ClCCl.sub.2 Br RO--CF.sub.2 CCl.sub.2 H6. CF.sub.2 ClCBr.sub.3 RO--CF.sub.2 CHBr.sub.27. CF.sub.2 ClCBr.sub.2 Cl RO--CF.sub.2 CHClBr8. CF.sub.2 BrCCl.sub.2 F RO--CF.sub.2 CHFCl9. CF.sub.2 BrCBr.sub.2 F RO--CF.sub.2 CHFBr10. CF.sub.2 BrCBrClF RO--CF.sub.2 CHFBr11. CF.sub.2 BrCCl.sub.3 RO--CF.sub.2 CHCl.sub.212. CF.sub.2 CrCCl.sub.2 Br RO--CF.sub.2 CHCl.sub.213. CF.sub.2 BrCBr.sub.3 RO--CF.sub.2 CHBr.sub.214. CF.sub.2 BrCBr.sub.2 Cl RO--CF.sub.2 CHClBr______________________________________
DETAILED DESCRIPTION
A particularly useful application of the invention is in the conversion of CF 2 ClCFCl 2 to CH 3 OCF 2 CHFCl by reaction with methanol and a base such as sodium hydroxide, sodium methylate, and the like, in the presence of a catalyst, as is described in greater detail in some of the examples below.
In this particular case, the ether product and methanol form a unique azeotrope that facilitates separation and recovery.
The use of the specific catalysts set forth above have been found essential in obtaining the improved yields, conversions, and reduced reaction times (such as over the reaction described in the Corley reference).
As indicated above, the primary, secondary, and tertiary amines, including cyclic amines, and diamines may be used as the catalysts hereof, either alone or preferably in combination with the aforesaid metal-containing catalysts. Preferably, the primary, secondary and tertiary alkanol amines are so utilized. Other suitable amines which may be employed as the catalysts hereof include:
______________________________________Methylamine (monomethylamine) AnilineDimethylamine PyridineDiethylamine Ethylene diamineTriethylamine N,N,N--trimethyl ethyleneIsopropyl-amine diamineDi-n-propylamine Diazo bicyclo (2,2,2)Piperidine octaneMorpholine N,N--diethyl ethyleneMonoethanolamine diamineDiethanolamine 1,2-cyclohexyleneHydrazine dinitrilo acetic acidEthylenediamine tetraacetic 3-dimethylamino propyl-acid amineTriethylene tetramine N--(2-amino ethyl morpholine)______________________________________
The metal-containing catalysts hereof may be in a finely divided or other suitable state. The catalyst may be copper in its metallic (elementary) state or in the form of the metal salt of an inorganic or organic acid, such as the chloride, bromide, nitrate, acetate, propionate, etc. of copper, silver, cobalt, rubidium, aluminum, manganese, nickel, iron, molybdenum, chromium, antimony and vanadium. Preferably, the metal will comprise copper, i.e., as metallic copper or in the form of a copper salt of an inorganic or organic acid. Preferably a copper-containing catalyst, such as elementary copper in powder form or a cuprous or cupric salt, is employed.
As is further noted above, combinations of the amine and metal-containing catalysts may be utilized in the present process. A highly preferred catalyst is a mixture of cuprous chloride and triethanolamine.
The alkanol reactant is a primary or secondary alcohol, preferably a 1 to 4 carbon alkanol (i.e., a lower primary or secondary alkanol), but such alkanols of any known chain length up to about 12 carbons are usable and can be expected to be effective, although even higher alcohols are operative. Since the alcohol is a reactant and is incorporated into the final product, the choice of alcohol depends only on the product desired, i.e., CH 3 OH gives CH 3 OCF 2 CY 2 H, CH 3 CH 2 OH gives CH 3 CH 2 OCF 2 CY 2 H, etc.
The inorganic base may be an alkali metal dissolved in the alkanol, an alkali metal or alkaline earth metal hydroxide, dry or in aqueous solution; or any strongly basic material that does not interfere with the desired reaction, such as, for example, ammonia or sodium carbonate.
In operating the process of this invention, the alkanol may be employed in excess over the theoretical amount required to effect the desired conversion to an ether, and functions both as a reactant and as a solvent, and may be present in substantial excess for that reason. The base may also be used in excess. The limits on the proportions of each reactant employed are those established by the practical considerations of reaction kinetics, and ease of recovery of the product.
The temperature of the reaction is dependent upon the particular reactants employed and the desired product, and may be in the range, for example, from about 0° C. to about 100°-120° C. or higher and, preferably, from about 20° C. to about 80° C. The temperature and/or pressure are such that the reaction mass is in the liquid state during the course of the reaction. The reaction is exothermic and once initiated, may require cooling, depending upon equipment available and other conditions.
In general, the time of the reaction depends upon the particular reactants employed, the temperature of the reaction, the efficacy of the catalyst, and other influencing factors. Generally a few hours is adequate to produce a suitable yield of any desired product.
One advantage of the present reaction utilizing a catalyst is that it may be carried out at atmospheric pressure. The pressure of reaction seems to have no material effect on the course of the reaction.
The product may be isolated by any suitable means from the reaction mass. Ordinarily, the product is isolated by distillation from the reaction mass at atmospheric or subatmospheric pressure, depending upon the boiling point of the reaction product, with the reaction products being recovered as the distillate. Another acceptable technique for recovery of the ether product of Eq. 3 (infra) is to water-wash the crude product to remove amines, and any water-soluble reaction products and by-products, and to cause precipitation of insolubles.
A general equation for a preferred reaction in accordance with this invention is: ##STR2##
There appear to be three steps in this conversion reaction, which can be represented by equations, as follows: ##STR3##
In order for the addition reaction to occur in Eq. 3, it is apparent that the unsaturated compound in Eq. 2 should have the configuration
CF.sub.2 ═CX.sub.2
where X is Cl or Br.
The ether products of Eq. 3 are generally known chemicals, and also have a variety of uses. Thus, the production of Compound I by the reaction where the initial halogenated alkane reactant is CF 2 ClCFCl 2 , the alkanol is methanol, and the recovered product is CH 3 OCF 2 CHFCl (Compound I), is of importance with respect to the production of the respiratory anesthetic enflurane, CHF 2 OCF 2 CHFCl, for which Compound I is a valuable intermediate.
In the production of Compound I, the reaction described in the general equation above is particularly useful because methanol forms a low boiling azeotrope with Compound I, which facilitates separation by distillation. Methanol can then be easily separated from the distillate by washing with water.
Thus, during the course of reacting CH 3 OH, NaOH and CF 2 ClCFCl 2 in the presence of specific catalysts, to prepare CH 3 OCF 2 CHFCl, this compound and methanol form an azeotropic mixture, b.p. 56° containing 86% CH 3 OCF 2 CHFCl and 14% CH 3 OH. This azeotrope allows a convenient separation of the product from the excess methanol. If no azeotrope were formed it would be difficult to separate CH 3 OCF 2 CHFCl, b.p. 70°, and excess methanol, b.p. 64°, by distillation, since all the methanol would have to be removed as overhead.
The process of the invention also has other useful applications, and other alcohols and haloethanes may also be reacted to produce halogenated ethers. For example:
CF.sub.2 ClCFCl.sub.2 +NaOH+CH.sub.3 CH.sub.2 OH→CH.sub.3 CH.sub.2 OCF.sub.2 CHFCl+NaCl+H.sub.2 O+CH.sub.3 CHO
and
CF.sub.2 ClCCl.sub.3 +NaOH+CH.sub.3 OH→CH.sub.3 OCF.sub.2 CHCl.sub.2 +NaCl+H.sub.2 O+CH.sub.2 O
CH 3 OCF 2 CHCl 2 is the formula for the valuable anesthetic, methoxyflurane, and the preceding equation represents a valuable new synthetic route for its preparation.
To explain the invention further, several demonstrations of it are reported in the following examples. All temperatures are in °C., and all parts and percentages by weight, unless expressly stated to be otherwise. The equations in this application are intended to illustrate the nature of the several reactions, and are not necessarily balanced.
EXAMPLE 1
Dechlorination, Methanol Addition Reaction
CF.sub.2 ClCFCl.sub.2 +NaOH+CH.sub.3 OH→CH.sub.3 OCF.sub.2 CHFCl (Product 1)
EXAMPLE 1A
Reaction Without Catalysis
A mixture of CF 2 ClCFCl 2 (94 g., 0.5 mole) 50% aqueous sodium hydroxide solution (120 g., 1.5 moles) and methanol (500 ml) was refluxed for twenty-four hours. The reaction mixture was distilled to give 91 g. of product b.p. 36°-62° C. This product was analyzed by gas chromatography in order to determine the percentages of CH 3 OCF 2 CHFCl, recovered by CF 2 ClCFCl 2 , and methanol present. The conversion to CH 3 OCF 2 CHFCl (Product 1) was 19% and 75% of the CF 2 ClCFCl 2 was recovered unchanged. The yield of CH 3 OCF 2 CHFCl (Product 1) was about 76%, i.e., 19/25 (100%).
Product 1 is a valuable material for use in the production of the gaseous anesthetic enflurane, of the formula CHF 2 OCF 2 CHFCl. It is produced from Product 1 by the following route: ##STR4##
EXAMPLE 1B
Reaction with Catalysis
The foregoing reaction was essentially repeated, but with catalysis, in accordance with the equation: ##STR5##
A mixture of CF 2 ClCFCl 2 (94 g., 0.5 mole), 50% aqueous sodium hydroxide solution (120 g., 1.5 moles), methanol (500 ml), CuCl 2 (5 g.), and triethanolamine (5 g.) was refluxed for 24 hours. The reaction mixture was distilled to give 59.5 g. of product containing 94% CH 3 OCF 2 CHFCl. No starting material was recovered; thus the conversion to CH 3 OCF 2 CHFCl was about 76% and the yield was about 76%.
A repetition of the reaction using 5 g. of CrCl 3 (chromium chloride) in place of copper chloride produced 45.7 g. of water-washed product (primarily CH 3 OCF 2 CHFCl, b.p. 50°-62° C.) and 1.7 g. believed to be unreacted or partially reacted material (b.p. 42°-49°). The conversion to CH 3 OCF 2 CHFCl (Product 1) was 57% and the yield was about 57%.
EXAMPLE 2
Other Alkali and Alcohol Reactants for the Dechlorination, Methanol Addition Reaction
CF.sub.2 ClCFCl.sub.2 +NaOCH.sub.3 +CH.sub.3 OH→CH.sub.3 OCF.sub.2 CHFCl (Product 1)
EXAMPLE 2A
Without Catalysis
Sodium (13.8 g., 0.6 equivalents) was dissolved in methanol (150 ml). CF 2 ClCFCl 2 (37.4 g., 0.2 mole) was then added and the reaction mixture refluxed for 20 hours. Distillation of the reaction mixture gave recovered CF 2 ClCFCl 2 and CH 3 OCF 2 CHFCl (Product 1). The conversion to CH 3 OCF 2 CHFCl (Product 1) was 39% and the yield 54%.
EXAMPLE 2B
With Catalysis
In a variation of this process, using a metal salt catalyst, sodium (4.6 g.) was dissolved in methanol (75 ml) and about 0.5 g. CuCl 2 added. 18.7 grams (0.1 mole) of CF 2 ClCFCl 2 was then added. There was no apparent immediate reaction. On addition of a small quantity (less than 0.5 g.) of triethanolamine, the reaction became exothermic with formation of a precipitate. After the reaction subsided, water was added, and 12 g. of product recovered as a precipitate. This product contained 17% unreacted CF 2 ClCFCl 2 , 4.5% CF 2 ClCFHCl, and 78% CH 3 OCF 2 CHFCl (Product 1) (about 0.06 moles) as shown by gas chromatography. The conversion to CH 3 OCF 2 CHFCl (Product 1) was 63% and the yield 71%.
EXAMPLE 3
Different Initial Halogenated Ethane
CF.sub.2 ClCCl.sub.3 +CH.sub.3 OH+NaOH→CH.sub.3 OCF.sub.2 CHCl.sub.2 (Product 3, methoxyflurane)
EXAMPLE 3A
Without Catalysis
A mixture of CF 2 ClCCl 3 (20 g., 0.1 mole), methanol (100 ml) and 50% aqueous sodium hydroxide solution (20 g, 0.25 mole) was refluxed for five hours. The reaction mixture was poured into water to yield 12.4 g. of water insoluble product containing 45% of CH 3 OCF 2 CHCl 2 .
Methoxyflurane is a valuable inhalant anesthetic.
EXAMPLE 3B
With Catalysis ##STR6##
A mixture of CF 2 ClCCl 3 (20 g., 0.1 mole), 50% aqueous sodium hydroxide (20 g., 0.25 mole), methanol (100 ml), CuCl 2 (0.5 g.) and TEA (triethanolamine) (0.5 g.) was refluxed for five hours. The reaction mixture was poured into water to give 11.2 g. of product containing 96.88% of CH 3 OCF 2 CHCl 2 . The conversion to CH 3 OCF 2 CHCl 2 (Product 3) was about 66% and the yield about 66%.
EXAMPLE 4
Use of Different Metallic Catalysts ##STR7##
A mixture of CF 2 ClCFCl 2 (94 g., 0.5 mole), methanol (500 ml), 50% aqueous sodium hydroxide (120 g., 1.5 moles) was refluxed for twenty-four hours and the product isolated by distillation and analyzed by gas chromatography to determine the amount of unrecovered unreacted CF 2 ClCFCl 2 and the amount of CF 3 OCF 2 CHFCl (Product 1) formed. The effect of metallic catalysts with and without added triethanolamine on the yields and conversions was determined by the following demonstrations of the reaction, which are summarized in tabular form:
______________________________________ CH.sub.3 OCF.sub.2 CHFCl(TEA = Triethanolamine) (Product 1)Catalysts Conversion, % Yield, %______________________________________5 g CrCl.sub.3, 5 g TEA 63 625 g CrCl.sub.3, -- 64 735 g VCl.sub.3, 5 g TEA 77 805 g VCl.sub.3, -- 65 721.4 g AgCl, 5 g TEA 41 685 g AgCl, 5 g TEA 66 759.5 g CoCl.sub.2, 5 g TEA 31 894.8 g RbCl, 5 g TEA 47 817.9 g MnCl.sub.2, 10 g TEA 53 717.9 g MnCl.sub.2, -- 24 6510 g MoCl.sub.5, -- 88 885 g CuCl.sub.2, 5 g TEA 80 855 g Cu, -- 50 715 g Cu, 5 g TEA 56 655 g Cu(NO.sub.3).sub.2, 5 g TEA 70 745 g Cu(SO.sub.4), 5 g TEA 73 755 g CuO, 5 g TEA 64 735 g Cu(OAc).sub.2, 5 g TEA 76 795 g Al(Cl.sub.2).sub.3, 5 g TEA 40 725 g Al(Cl).sub.3, -- 36 675 g FeCl.sub.3, 5 g TEA No Conversion5 g FeCl.sub.3, -- 40 69______________________________________
EXAMPLE 5
Use of Different Amine Catalysts, All with CuCl 2 ##STR8##
A mixture of CF 2 ClCFCl 2 (94 g., 0.5 mole), 50% aqueous sodium hydroxide solution (120 g, 1.5 mole), methanol (500 ml), CuCl 2 (5 g.), and an amine catalyst, was refluxed for 24 hours. The CH 3 OCF 2 CHFCl product and recovered unreacted CF 2 ClCFCl 2 were recovered by distillation and analyzed by gas chromatography. Yields and conversions were calculated from the chromatographic analyses.
The yields and conversions when different amines were used are as follows:
______________________________________Amine Conversion, % Yield, %______________________________________Pyridine (3 g) 48 70Ethanolamine (2.5 g) 83 85Ethylene diamine (2.1 g) 73 81Triethylene tetramine (2.5 g) 80 80N,N,N--trimethylethylene diamine (3.6 g) 81 81N,N--diethylethylenediamine (4 g) 81 811,2-cyclohexylene-dinitrilo acetic acid (12 g) 44 633-dimethylamino propyl-amine (3.6 g) 55 66Ethylenediamine tetraacetic acid (10.2 g) 46 74Diazo bicyclo (2,2,2)octane (3.9 g) 51 73N--(2-amino ethyl mor-pholine) (4.6 g) 61 81______________________________________
A repetition of the reaction but using as catalysts 5 g. VCl 3 and 12 g. benzyl trimethyl ammonium methoxide produced a conversion of 35% and a yield of 73%; and repetition with 5 g. VCl 3 and 6.3 g. ethanolamine produced a conversion of 71% and a yield of 84%. The combination of 5 g. VCl 3 with 3.4 g. N,N,N-trimethylenediamine led to a conversion of 61% and a yield of 82%, whereas the combination of 5 g. of MOCl 5 with 5.3 g. ethanolamine produced a conversion of 27% and a yield of 69%, and the combination of 5 g. of MoCl 5 with 3.2 g. triethylene tetramine produced a conversion of 81%.
Other combinations of catalysts that have been used in this reaction, with comparable results, include the following:
______________________________________Inorganic Catalytic Amine CatalyticComponent Component______________________________________MoO.sub.3, 5 g. TEA, 12.5 g.MoO.sub.3, 5 g. triethylenetetra- amine, 3.2 g.______________________________________
EXAMPLE 6
Catalyzed Dechlorination, Methanol Addition Reaction; With Product Fractionation by Means of an Azeotrope
CF.sub.2 ClCFCl.sub.2 +CH.sub.3 OH+NaOH→CH.sub.3 OCF.sub.2 CHFCl (Product 1)
A mixture of CF 2 ClCFCl 2 (470 g., 2.5 mole), methanol (1 liter), 50% aqueous sodium hydroxide (600 g., 7.5 moles), CuCl 2 (25 g), and triethanolamine (10 g.) was refluxed for seven hours, allowed to stand at room temperature for 16 hours, then refluxed for an additional eight hours.
Water (500 ml) was added and the reaction mixture fractionated to give 68 g. of product, fraction 6a, b.p. 35°-46°, and 286 g. of product, fraction 6b, b.p. 56°.
The lower boiling fraction 6a, was 78% CF 2 ClCFCl 2 and 12% CH 3 OCF 2 CHFCl (Product 1) as shown by gas chromatography.
The higher boiling fraction, 6b, was an azeotrope of CH 3 OCF 2 CHFCl (Product 1) and methanol, b.p. 56°, which was washed with water to give 224 g. of CH 3 OCF 2 CHFCl (Product 1) containing 1.39% of CF 2 ClCFCl 2 . The yield of Product 1 was based on theoretical 100% conversion of CF 2 ClCFCl 2 was about 2% in fraction 6a and about 60.5% in fraction 6b, with a total yield of about 62.5%.
The present invention can thus make use of specific catalysts and an economical, readily available reactant, CF 2 ClCFCl 2 , for the efficient synthesis of a valuable ether product. While this ether product has primary present interest as an intermediate, it and other ether products that can be prepared by the process of this invention are useful as fumigants, solvents, chemical intermediates, and in some cases as relatively inert reaction media.
The process has the advantage of being highly specific, in the sense that few unwanted materials appear in the reaction mixture produced. Product recoveries and purifications are thus facilitated and made less expensive. The process also provides new ways to synthesize valuable materials.
While the invention has been disclosed herein by reference to the details of preferred embodiments, it is to be understood that the disclosure is intended in an illustrative sense, and it is contemplated that modifications may be made in the process within the spirit of the invention and the scope of the appended claims.
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Processes for the preparation of certain halogenated aliphatic ethers are described, and in particular the preparation of 1,1,2-trifluoro-2-chloroethyl methyl ether, i.e., CH 3 OCF 2 CHFCl. This particular ether has many uses, and is a valuable material for use in the production of the inhalant anesthetic enflurane, 1,1,2-trifluoro-2-chloroethyl difluoromethyl ether, i.e., CF 2 HOCF 2 CHFCl, made and sold under the trademark ETHRANE by Airco, Inc., Montvale, New Jersey 07645.
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STATEMENT AS TO RIGHTS TO INVENTIONS MADE UNDER FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
This invention was made with Government support under Grant Number 9835100-6150 awarded by the United States Department of Agriculture. The Government has certain rights in this invention.
FIELD OF THE INVENTION
The present invention is generally related to plant genetic engineering. In particular, the invention is directed to new dehydroascorbate reductase (“DHAR”) genes useful in modulating ascorbic acid levels in plants.
BACKGROUND OF THE INVENTION
Despite its essential role in supporting life, oxygen can be highly damaging to an organism under certain conditions. For plants, the inadvertent production of active oxygen species (e.g., O 2- , H 2 O 2 , hydroxyl radicals, and singlet oxygen) occurs as a consequence of normal photosynthetic activity. Exposure to many abiotic stresses can exacerbate the production of active oxygen species, including cold, drought, salt, or high light. The production of active oxygen species near the photosynthetic machinery can result in substantial damage and thus reduce photosynthetic capacity or, under severe conditions, lead to death of the organ or entire plant. Active oxygen species can be produced in other cellular compartments including the mitochondria which themselves have substantial electron transport activity as well as in peroxisomes during the oxidation of glycollate. Active oxygen species are produced in response to attack by many pathogens. Nevertheless, not all active oxygen species are produced by plant processes or responses. Active oxygen species can invade a plant when it is exposed to pollutants such as ozone. However, the production of active oxygen species is not always inadvertent. Active oxygen species can play an important role as signaling molecules. For example, oxygen photoreduction (the Mehler peroxidase reaction) results from the transfer of electrons from photosystem I (PSI) to oxygen to form superoxides which disproportionates to hydrogen peroxide (H 2 O 2 ), a reaction that is catalyzed by superoxide dismutase. The Mehler reaction thus serves to maintain electron flow through PSI and maintains its correct function. H 2 O 2 acts as a signaling molecule involved in many stress and defense responses (Van Breusegem et al., 2001) and in guard cells can induce stomatal closure (Pei et al., 2000; Zhang et al., 2001). Consequently, plants have had to evolve mechanisms to limit the deleterious effects of many active oxygen species and simultaneously use the production or exposure of certain active oxygen species as information about alterations to the internal or external environment of the plant to mount correct responses to its current conditions. Plants, like most organisms, rely on an array of antioxidants to detoxify active oxygen species.
Of the antioxidants found in plants, ascorbic acid (“ASC”) is the most abundant and is present in millimolar concentrations that range from 10 to 300 mM (Smirnoff, 2000). Glutathione, for example, the other major soluble antioxidant, is typically present at only 10% of the concentration of ASC (Noctor and Foyer, 1998). In its antioxidant role, ASC is used by ascorbate peroxidase to convert H 2 O 2 to water and ASC can directly scavenge superoxide, hydroxyl radicals, and singlet oxygen. ASC also contributes to the regulation of the cellular redox state and is used to regenerate a-tocopherol from a-tocopherol radicals that are produced from the reduction of lipid peroxyl radicals. ASC can serve as an enzyme co-factor, e.g., for violaxanthin de-epoxidase (VDE) (Eskling et al., 1997) which catalyzes the conversion of violaxanthin to zeaxanthin (the Xanthophyll cycle), which is required for the dissipation of excess excitation energy during non-photochemical quenching. ASC is also involved in the regulation of cell elongation and progression through the cell cycle (reviewed in Horemans et al., 2000). This partial list of cellular functions demonstrates the importance of ASC to the health and growth of the cell, and ultimately, the plant.
ASC biosynthesis differs from that in mammals and has been shown to result from the oxidation of L-galactose to L-galactono-1,4-lactone which in turn is oxidized to ASC by L-galactono-1,4-lactone dehydrogenase. Although most of the biosynthetic pathway is carried out in the cytosol, the final step occurs at the inner mitochondrial membrane where the L-galactono-1,4-lactone dehydrogenase is located (Siendones et al., 1999; Bartoli et al., 2000). Feedback inhibition of ASC synthesis by the ASC pool size has been demonstrated (Pallanca and Smirnoff, 2000). Given that ASC is present in most compartments of the cell including the mitochondria, cytosol, chloroplast stroma and thylakoid lumen, and apoplast, it is transported throughout the cell and to the apoplast through specific transport across the chloroplast envelope and plasma membrane (Rautenkranz et al., 1994; Horemans et al., 1997). Following its use by ascorbate peroxidase in H 2 O 2 detoxification, its participation in the Xanthophyll cycle, or its reduction of a-tocopherol radicals as part of non-photochemical quenching, ASC is oxidized to the monodehydroascorbate (MDHA) radical which disproportionates to ASC and dehydroascorbate (DHA). Although the rate of ASC synthesis is not fast, ASC is rapidly regenerated from DHA, a reaction catalyzed by DHAR and which uses glutathione as the reductant. Glutathione reductase uses NADPH produced principally from PSI to regenerate glutathione from oxidized glutathione. Consequently, the detoxification of AOS species by this ascorbate-glutathione pathway involves the transfer of electrons from PSI to NADPH to glutathione to ASC to H 2 O 2 in a series of reactions in which there is no net loss of ASC or glutathione. Given its role in regenerating ASC, the principal function of DHAR activity would be expected to maintain the existing pool of ASC in a reduced state needed to meet the challenge imposed by those stresses that generate active oxygen species.
As an antioxidant, one of ASC's role in plants is to scavenge hydrogen peroxide. Hydrogen peroxide is involved in regulating the stomatal openings formed by the presence of pairs of guard cells in plants. Stomatal closure can be triggered by an increase in the intracellular concentration of hydrogen peroxide in guard cells. Stomatal openings can be triggered by a decrease in the intracellular concentration of hydrogen peroxide in guard cells. Plants control exposure to environmental conditions by tightly regulating stomatal aperture. Stomatal closures limits exposure to plants of certain toxins that may be circulating in the environment and protect the plant from drought conditions. Stomatal closures, however, also limit CO 2 assimilation and increase the concentration of NADPH in plants as a consequence of reduction in Calvin cycle activity. Because of the importance of ASC levels in plants, there exists a need for closely regulating its production. This invention meets this and other needs.
SUMMARY OF THE INVENTION
The present invention provides DHAR nucleic acids and polypeptides. In one aspect of the present invention, the invention provides an isolated nucleic acid encoding a DHAR polypeptide comprising an amino acid sequence at least 80% identical to SEQ ID NO: 1, wherein the sequence is not SEQ ID NO: 9, SEQ ID NO: 13 or SEQ ID NO: 15.
In a second aspect of the present invention, a DHAR nucleic acid of the present invention further comprises a chloroplast transit signal sequence.
In a third aspect of the present invention, a DHAR nucleic acid is isolated from wheat, tobacco, maize, or tomato.
In a fourth aspect, the present invention provides a recombinant expression cassette comprising a promoter sequence operably linked to a nucleic acid encoding a DHAR polypeptide comprising an amino acid sequence at least 80% identical to SEQ ID NO: 1. In one embodiment of the present invention, the nucleic acid is operably linked to the promoter sequence in an antisense orientation. In a second embodiment, the nucleic acid is isolated from wheat, tobacco, maize, tomato, rice, or spinach. In a third embodiment, the promoter is a constitutive promoter. In a fourth embodiment, the promoter is an organ specific promoter. In a fifth embodiment, the promoter preferentially directs expression in guard cells. In a sixth embodiment, the nucleic acid encodes a DHAR polypeptide comprising an amino acid sequence substantially identical to SEQ ID NOs: 3, 5, 7, 9, 11, 13, or 15. In a seventh embodiment, the nucleic acid encodes a DHAR polypeptide comprising an amino acid sequence comprising SEQ ID NOs. 3, 5, 7, 9, 11, 13, or 15.
In a fifth aspect, the present invention provides a transgenic plant comprising a recombinant expression cassette comprising a plant promoter sequence operably linked to a nucleic acid encoding a DHAR polypeptide comprising an amino acid sequence at least 80% identical to SEQ ID NO: 1. In one embodiment, the plant is wheat, tobacco, maize, tomato, spinach, or rice. In a second embodiment, the nucleic acid is operably linked to the promoter sequence in an antisense orientation. In a third embodiment, the promoter is an organ specific promoter. In a fourth embodiment, the promoter preferentially directs expression in guard cells. In a fifth embodiment, the nucleic acid encodes a DHAR polypeptide comprising an amino acid sequence substantially identical to SEQ ID NOs: 3, 5, 7, 9, 11, 13, or 15. In a sixth embodiment, the nucleic acid encodes a DHAR polypeptide comprising an amino acid sequence comprising SEQ ID NOs. 3, 5, 7, 9, 11, 13, or 15.
In a sixth aspect, the present invention provides a method of increasing ascorbic acid levels in a plant comprising introducing a construct comprising a promoter operably linked to a nucleic acid encoding a DHAR polypeptide comprising an amino acid sequence at least 80% identical to SEQ ID NO: 1. In one embodiment, the construct is introduced into the plant through a sexual cross. In a second embodiment, the expression cassette is introduced into the plant using Agrobacterium . In a third embodiment, the expression cassette is introduced into the plant using biolistics. In a fourth embodiment, the plant is a selected from the group consisting of wheat, tobacco, maize, tomato, rice or spinach. In a fifth embodiment, the method further comprising detecting a plant having increased biomass or yield. In a sixth embodiment, the promoter is an organ specific promoter. In a seventh embodiment, the promoter preferentially directs expression in guard cells. In an eighth embodiment, the nucleic acid encodes a DHAR polypeptide comprising an amino acid sequence substantially identical to SEQ ID NOs: 3, 5, 7, 9, 11, 13, or 15. In a ninth embodiment, the nucleic acid encodes a DHAR polypeptide comprising an amino acid sequence comprising SEQ ID NOs. 3, 5, 7, 9, 11, 13, or 15.
In a seventh aspect, the present invention provides a method of decreasing ascorbic acid levels in a plant comprising introducing a construct comprising a promoter operably linked to a nucleic acid encoding a DHAR polypeptide comprising an amino acid sequence at least 80% identical to SEQ ID NO: 1. In one embodiment, the nucleotide sequence is operably linked to the promoter sequence in an antisense orientation. In a second embodiment, the expression cassette is introduced into the plant through a sexual cross. In a third embodiment, the expression cassette is introduced into the plant using Agrobacterium . In a fourth embodiment, the expression cassette is introduced into the plant using biolistics. In a fifth embodiment, the plant is selected from the group consisting of wheat, tobacco, maize, tomato, rice, or spinach. In a sixth embodiment, the method further comprises detecting increased drought tolerance in the plant. In a seventh embodiment, the method further comprises detecting decreased sensitivity to toxins in the plant. In an eight embodiment, the toxin is selected from the group consisting of ozone, nitrous oxide, and sulfur oxide. In a ninth embodiment, the promoter is an organ specific promoter. In a tenth embodiment, the promoter preferentially directs expression in guard cells. In an eleventh embodiment, the nucleic acid encodes a DHAR polypeptide comprising an amino acid sequence substantially identical to SEQ ID NOs: 3, 5, 7, 9, 11, 13, or 15. In a twelfth embodiment, the nucleic acid encodes a DHAR polypeptide comprising an amino acid sequence comprising SEQ ID NOs. 3, 5, 7, 9, 11, 13, or 15.
In an eighth aspect of the present invention, the DHAR polypeptide comprises SEQ ID NO: 1.
In ninth aspect of the present invention, the DHAR polypeptide comprises SEQ ID NO: 3, SEQ ID NO: 5, SEQ ID NO: 7, or SEQ ID NO: 11.
In a tenth aspect, the present invention provides an isolated DHAR polypeptide comprising an amino acid sequence at least 80% identical to SEQ ID NO: 1, wherein the sequence is not SEQ ID NO: 9, SEQ ID NO: 13 or SEQ ID NO: 15. In one embodiment, the DHAR polypeptide further comprises a chloroplast transit peptide. In a second embodiment, the DHAR polypeptide comprises SEQ ID NO: 1. In a third embodiment, the DHAR polypeptide comprises SEQ ID NO: 3, SEQ ID NO: 5, SEQ ID NO: 7, or SEQ ID NO: 11. In a fourth embodiment, the DHAR polypeptide comprises an amino acid sequence substantially identical to SEQ ID NO:s 3, 5, 7, or 11.
In an eleventh aspect, the present invention provides an isolated nucleic acid encoding a DHAR polypeptide comprising a nucleic acid sequence substantially identical to SEQ ID NOS.: 2, 4, 6 or 10.
Definitions
The phrase “nucleic acid sequence” refers to a single or double-stranded polymer of deoxyribonucleotide or ribonucleotide bases read from the 5′ to the 3′ end. It includes chromosomal DNA, self-replicating plasmids, infectious polymers of DNA or RNA and DNA or RNA that performs a primarily structural role.
The term “promoter” refers to regions or sequence located upstream and/or downstream from the start of transcription and which are involved in recognition and binding of RNA polymerase and other proteins to initiate transcription. A “plant promoter” is a promoter capable of initiating transcription in plant cells.
The term “plant” includes whole plants, shoot vegetative organs and/or structures (e.g. leaves, stems and tubers), roots, flowers and floral organs (e.g. bracts, sepals, petals, stamens, carpels, anthers), ovules (including egg and central cells), seed (including zygote, embryo, endosperm, and seed coat), fruit (e.g., the mature ovary), seedlings, plant tissue (e.g. vascular tissue, ground tissue, and the like), cells (e.g. guard cells, egg cells, trichomes and the like), and progeny of same. The class of plants that can be used in the method of the invention is generally as broad as the class of higher and lower plants amenable to transformation techniques, including angiosperms (monocotyledonous and dicotyledonous plants), gymnosperms, ferns, and multicellular algae. It includes plants of a variety of ploidy levels, including aneuploid, polyploid, diploid, haploid and hemizygous.
A polynucleotide sequence is “heterologous to” an organism or a second polynucleotide sequence if it originates from a foreign species, or, if from the same species, is modified from its original form. For example, a promoter operably linked to a heterologous coding sequence refers to a coding sequence from a species different from that from which the promoter was derived, or, if from the same species, a coding sequence which is not naturally associated with the promoter (e.g. a genetically engineered coding sequence or an allele from a different ecotype or variety).
A polynucleotide “exogenous to” an individual plant is a polynucleotide which is introduced into the plant by any means other than by a sexual cross. Examples of means by which this can be accomplished are described below, and include Agrobacterium-mediated transformation, biolistic methods, electroporation, and the like. Such a plant containing the exogenous nucleic acid is referred to here as a T1 (e.g. in Arabidopsis by vacuum infiltration) or R0 (for plants regenerated from transformed cells in vitro) generation transgenic plant. Transgenic plants that arise from sexual cross or by selfing are descendants of such a plant.
An “DHAR nucleic acid” or “DHAR polynucleotide sequence” of the invention is a subsequence or full length polynucleotide sequence which, encodes a DHAR polypeptide and its complement, e.g., SEQ ID NOS: 2, 4, 6 or 8. DHAR gene products of the invention (e.g., mRNAs or polypeptides) are characterized by the ability to modulate ASC levels and thereby control such phenotypes as Vitamin C content, enhanced biomass, stomatal closing, stomatal opening, whole plant transpirational water loss during drought, increased CO 2 assimilation, decreased toxin sensitivity. A DHAR polynucleotide of the invention typically comprises a coding sequence at least about 250 nucleotides to about 2000 nucleotides in length. Usually the DHAR nucleic acids of the invention are from about 400 to about 1500 nucleotides.
A DHAR nucleic acid of the present invention may also include a chloroplast transit signal sequence. Chloroplast transit signal sequences encode chloroplast transit peptides and initiate DHAR polypeptide translocation into the chloroplast. Chloroplast transit peptides are well known in the art and can be identified by standard means, e.g., analysis with ChloroP (Emmanuelsson et al., Protein Sci. 8:978-984 or Schein et al., Nucleic Acids Res, 15;29(16)E82 (2001)). The site at which the transit peptide is cleaved from a DHAR polypeptide can be determined by known methods, e.g., comparing the predicted amino acid sequence of the transit sequence with the amino-terminal of a purified chloroplast DHAR polypeptide. An exemplary transit peptide sequence can be found in Shimaoka et al. Plant Cell Physiol., 41(10):1110-1118(2000).
A consensus sequence is a minimum nucleotide or amino acid sequence found to be common in genes or proteins from different organisms. Typically, the genes or proteins are associated with a specific function. The DHAR consensus sequence of the present invention is a minimum amino acid sequence common in DHAR polypeptides. The DHAR consensus sequence of the present invention was derived from the protein sequences of the following DHAR polypeptides: wheat, rice, tomato, maize, tobacco, and Arabidopsis . Standard methodologies were used to align known DHAR amino acid sequences to create the DHAR consensus sequence.
In the case of both expression of transgenes and inhibition of endogenous genes (e.g., by antisense, or co-suppression) one of skill will recognize that the inserted polynucleotide sequence need not be identical, but may be only “substantially identical” to a sequence of the gene from which it was derived. As explained below, these substantially identical variants are specifically covered by the term DHAR nucleic acid.
In the case where the inserted polynucleotide sequence is transcribed and translated to produce a functional polypeptide, one of skill will recognize that because of codon degeneracy a number of polynucleotide sequences will encode the same polypeptide. These variants are specifically covered by the terms “DHAR nucleic acid”, “DHAR polynucleotide” and their equivalents. In addition, the terms specifically include those full length sequences substantially identical (determined as described below) with a DHAR polynucleotide sequence and that encode proteins that retain the function of the DHAR polypeptide (e.g., resulting from conservative substitutions of amino acids in the DHAR polypeptide).
Two nucleic acid sequences or polypeptides are said to be “identical” if the sequence of nucleotides or amino acid residues, respectively, in the two sequences is the same when aligned for maximum correspondence as described below. The terms “identical” or percent “identity,” in the context of two or more nucleic acids or polypeptide sequences, refer to two or more sequences or subsequences that are the same or have a specified percentage of amino acid residues or nucleotides that are the same, when compared and aligned for maximum correspondence over a comparison window, as measured using one of the following sequence comparison algorithms or by manual alignment and visual inspection. When percentage of sequence identity is used in reference to proteins or peptides, it is recognized that residue positions that are not identical often differ by conservative amino acid substitutions, where amino acids residues are substituted for other amino acid residues with similar chemical properties (e.g., charge or hydrophobicity) and therefore do not change the functional properties of the molecule. Where sequences differ in conservative substitutions, the percent sequence identity may be adjusted upwards to correct for the conservative nature of the substitution. Means for making this adjustment are well known to those of skill in the art. Typically this involves scoring a conservative substitution as a partial rather than a full mismatch, thereby increasing the percentage sequence identity. Thus, for example, where an identical amino acid is given a score of 1 and a non-conservative substitution is given a score of zero, a conservative substitution is given a score between zero and 1. The scoring of conservative substitutions is calculated according to, e.g., the algorithm of Meyers & Miller, Computer Applic. Biol. Sci. 4:11-17 (1988) e.g., as implemented in the program PC/GENE (Intelligenetics, Mountain View, Calif., USA).
The phrase “substantially identical,” in the context of two nucleic acids or polypeptides, refers to a sequence or subsequence that has at least 25% sequence identity with a reference sequence. Alternatively, percent identity can be any integer from 25% to 100%. More preferred embodiments include at least: 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or 99%, compared to a reference sequence using the programs described herein; preferably, BLAST using standard parameters, as described below. This definition also refers to the complement of a test sequence, when the test sequence has substantial identity to a reference sequence.
For sequence comparison, typically one sequence acts as a reference sequence, to which test sequences are compared. When using a sequence comparison algorithm, test and reference sequences are entered into a computer, subsequence coordinates are designated, if necessary, and sequence algorithm program parameters are designated. Default program parameters can be used, or alternative parameters can be designated. The sequence comparison algorithm then calculates the percent sequence identities for the test sequences relative to the reference sequence, based on the program parameters.
A “comparison window”, as used herein, includes reference to a segment of any one of the number of contiguous positions selected from the group consisting of from 20 to 600, usually about 50 to about 200, more usually about 100 to about 150 in which a sequence may be compared to a reference sequence of the same number of contiguous positions after the two sequences are optimally aligned. Methods of alignment of sequences for comparison are well-known in the art. Optimal alignment of sequences for comparison can be conducted, e.g., by the local homology algorithm of Smith & Waterman, Adv. Appl. Math. 2:482 (1981), by the homology alignment algorithm of Needleman & Wunsch, J. Mol. Biol. 48:443 (1970), by the search for similarity method of Pearson & Lipman, Proc. Nat'l. Acad. Sci. USA 85:2444 (1988), by computerized implementations of these algorithms (GAP, BESTFIT, FASTA, and TFASTA in the Wisconsin Genetics Software Package, Genetics Computer Group, 575 Science Dr., Madison, Wis.), or by manual alignment and visual inspection.
One example of a useful algorithm is PILEUP. PILEUP creates a multiple sequence alignment from a group of related sequences using progressive, pairwise alignments to show relationship and percent sequence identity. It also plots a tree or dendogram showing the clustering relationships used to create the alignment. PILEUP uses a simplification of the progressive alignment method of Feng & Doolittle, J. Mol. Evol. 35:351-360 (1987). The method used is similar to the method described by Higgins & Sharp, CABIOS 5:151-153 (1989). The program can align up to 300 sequences, each of a maximum length of 5,000 nucleotides or amino acids. The multiple alignment procedure begins with the pairwise alignment of the two most similar sequences, producing a cluster of two aligned sequences. This cluster is then aligned to the next most related sequence or cluster of aligned sequences. Two clusters of sequences are aligned by a simple extension of the pairwise alignment of two individual sequences. The final alignment is achieved by a series of progressive, pairwise alignments. The program is run by designating specific sequences and their amino acid or nucleotide coordinates for regions of sequence comparison and by designating the program parameters. For example, a reference sequence can be compared to other test sequences to determine the percent sequence identity relationship using the following parameters: default gap weight (3.00), default gap length weight (0.10), and weighted end gaps.
Another example of algorithm that is suitable for determining percent sequence identity and sequence similarity is the BLAST algorithm, which is described in Altschul et al., J. Mol. Biol. 2 15:403-410 (1990). Software for performing BLAST analyses is publicly available through the National Center for Biotechnology Information This algorithm involves first identifying high scoring sequence pairs (HSPs) by identifying short words of length W in the query sequence, which either match or satisfy some positive-valued threshold score T when aligned with a word of the same length in a database sequence. T is referred to as the neighborhood word score threshold (Altschul et al, supra). These initial neighborhood word hits act as seeds for initiating searches to find longer HSPs containing them. The word hits are extended in both directions along each sequence for as far as the cumulative alignment score can be increased. Extension of the word hits in each direction are halted when: the cumulative alignment score falls off by the quantity X from its maximum achieved value; the cumulative score goes to zero or below, due to the accumulation of one or more negative-scoring residue alignments; or the end of either sequence is reached. The BLAST algorithm parameters W, T, and X determine the sensitivity and speed of the alignment. The BLAST program uses as defaults a wordlength (W) of 11, the BLOSULM62 scoring matrix (see Henikoff& Henikoff, Proc. Nati. Acad. Sci. USA 89:10915 (1989)) alignments (B) of 50, expectation (E) of 10, M=5, N=4, and a comparison of both strands.
The BLAST algorithm also performs a statistical analysis of the similarity between two sequences (see, e.g., Karlin & Altschul, Proc. Nat'l. Acad. Sci. USA 90:5873-5787 (1993)). One measure of similarity provided by the BLAST algorithm is the smallest sum probability (P(N)), which provides an indication of the probability by which a match between two nucleotide or amino acid sequences would occur by chance. For example, a nucleic acid is considered similar to a reference sequence if the smallest sum probability in a comparison of the test nucleic acid to the reference nucleic acid is less than about 0.01, more preferably less than about 10-5, and most preferably less than about 10-20.
“Conservatively modified variants” applies to both amino acid and nucleic acid sequences. With respect to particular nucleic acid sequences, conservatively modified variants refers to those nucleic acids which encode identical or essentially identical amino acid sequences, or where the nucleic acid does not encode an amino acid sequence, to essentially identical sequences. Because of the degeneracy of the genetic code, a large number of functionally identical nucleic acids encode any given protein. For instance, the codons GCA, GCC, GCG and GCU all encode the amino acid alanine. Thus, at every position where an alanine is specified by a codon, the codon can be altered to any of the corresponding codons described without altering the encoded polypeptide. Such nucleic acid variations are “silent variations,” which are one species of conservatively modified variations. Every nucleic acid sequence herein which encodes a polypeptide also describes every possible silent variation of the nucleic acid. One of skill will recognize that each codon in a nucleic acid (except AUG, which is ordinarily the only codon for methionine) can be modified to yield a functionally identical molecule. Accordingly, each silent variation of a nucleic acid which encodes a polypeptide is implicit in each described sequence.
As to amino acid sequences, one of skill will recognize that individual substitutions, in a nucleic acid, peptide, polypeptide, or protein sequence which alters a single amino acid or a small percentage of amino acids in the encoded sequence is a “conservatively modified variant” where the alteration results in the substitution of an amino acid with a chemically similar amino acid. Conservative substitution tables providing functionally similar amino acids are well known in the art.
The following six groups each contain amino acids that are conservative substitutions for one another:
1) Alanine (A), Serine (S), Threonine (T); 2) Aspartic acid (D), Glutamic acid (E); 3) Asparagine (N), Glutamine (Q); 4) Arginine (R), Lysine (K); 5) Isoleucine (I), Leucine (L), Methionine (M), Valine (V); and 6) Phenylalanine (F), Tyrosine (Y), Tryptophan (W). ps (see, e.g., Creighton, Proteins (1984)
One indication that two nucleic acid sequences or polypeptides are substantially identical is that the polypeptide encoded by the first nucleic acid is immunologically cross reactive with the antibodies raised against the polypeptide encoded by the second nucleic acid. Thus, a polypeptide is typically substantially identical to a second polypeptide, for example, where the two peptides differ only by conservative substitutions. Another indication that two nucleic acid sequences are substantially identical is that the two molecules or their complements hybridize to each other under stringent conditions, as described below.
The phrase “selectively (or specifically) hybridizes to” refers to the binding, duplexing, or hybridizing of a molecule only to a particular nucleotide sequence under stringent hybridization conditions when that sequence is present in a complex mixture (e.g., total cellular or library DNA or RNA).
The phrase “stringent hybridization conditions” refers to conditions under which a probe will hybridize to its target subsequence, typically in a complex mixture of nucleic acid, but to no other sequences. Stringent conditions are sequence-dependent and will be different in different circumstances. Longer sequences hybridize specifically at higher temperatures. An extensive guide to the hybridization of nucleic acids is found in Tijssen, Techniques in Biochemistry and Molecular Biology—Hybridization with Nucleic Probes, “Overview of principles of hybridization and the strategy of nucleic acid assays” (1993). Generally, highly stringent conditions are selected to be about 5-10° C. lower than the thermal melting point (Tm) for the specific sequence at a defined ionic strength pH. Low stringency conditions are generally selected to be about 15-30° C. below the Tm. The Tm is the temperature (under defined ionic strength, pH, and nucleic concentration) at which 50% of the probes complementary to the target hybridize to the target sequence at equilibrium (as the target sequences are present in excess, at Tm, 50% of the probes are occupied at equilibrium). Stringent conditions will be those in which the salt concentration is less than about 1.0 M sodium ion, typically about 0.01 to 1.0 M sodium ion concentration (or other salts) at pH 7.0 to 8.3 and the temperature is at least about 30° C. for short probes (e.g., 10 to 50 nucleotides) and at least about 60° C. for long probes (e.g., greater than 50 nucleotides). Stringent conditions may also be achieved with the addition of destabilizing agents such as formamide. For selective or specific hybridization, a positive signal is at least two times background, preferably 10 time background hybridization.
Nucleic acids that do not hybridize to each other under stringent conditions are still substantially identical if the polypeptides which they encode are substantially identical. This occurs, for example, when a copy of a nucleic acid is created using the maximum codon degeneracy permitted by the genetic code. In such cases, the nucleic acids typically hybridize under moderately stringent hybridization conditions.
In the present invention, genomic DNA or cDNA comprising DHAR nucleic acids of the invention can be identified in standard Southern blots under stringent conditions using the nucleic acid sequences disclosed here. For the purposes of this disclosure, suitable stringent conditions for such hybridizations are those which include a hybridization in a buffer of 40% formamide, 1 M NaCl, 1% SDS at 37° C., and at least one wash in 0.2×SSC at a temperature of at least about 50° C., usually about 55° C. to about 60° C., for 20 minutes, or equivalent conditions. A positive hybridization is at least twice background. Those of ordinary skill will readily recognize that alternative hybridization and wash conditions can be utilized to provide conditions of similar stringency.
A further indication that two polynucleotides are substantially identical is if the reference sequence, amplified by a pair of oligonucleotide primers, can then be used as a probe under stringent hybridization conditions to isolate the test sequence from a cDNA or genomic library, or to identify the test sequence in, e.g., an RNA gel or DNA gel blot hybridization analysis.
DETAILED DESCRIPTION OF THE INVENTION
The present invention provides novel isolated nucleic acids and polypeptides that can be used to modulate (e.g., increase or decrease) ASC levels in plants. Recombinant constructs incorporating the nucleic acids of the invention operably linked to various promoters are used to generate transformed plant cells and transgenic plants.
The invention provides both compositions and means to both increase or decrease ascorbic acid levels in plants. An increase in the expression of DHAR, the enzyme responsible for regenerating ascorbic acid from its oxidized form results in an increase in the level of ascorbic acid in plants. The DHAR polynucleotides of the present invention therefore can be used to create transgenic plants with higher or lower Vitamin C content. Ascorbic acid, in its role as an antioxidant, scavenges active oxygen species in plants. The DHAR polynucleotides of the present invention therefore can also be used to confer broad protection against oxidative stresses in plants. One role of ASC is to scavenge hydrogen peroxide in plant guard cells. The intracellular concentration of hydrogen peroxide in guard cells controls stomatal opening and closings. Increased levels of hydrogen peroxide cause stomatal closures whereas decreased levels cause stomatal openings. Closed stomatas protect the plant against environmental conditions such as aerosolized toxins and drought (transpiration occurs through the stomata). Opened stomatas allow for greater exchange between the plant and the outside environment. Plants with increased ASC levels display increased carbon fixation activity and enhanced biomass. The DHAR polynucleotides of the present invention therefore can be used to protect plants against environmental conditions or to provide for a greater exchange between plants and the environment.
Isolation of Nucleic Acids of the Invention
Generally, the nomenclature and the laboratory procedures in recombinant DNA technology described below are those well known and commonly employed in the art. Standard techniques are used for cloning, DNA and RNA isolation, amplification and purification. Generally enzymatic reactions involving DNA ligase, DNA polymerase, restriction endonucleases and the like are performed according to the manufacturer's specifications. These techniques and various other techniques are generally performed according to Sambrook et al., Molecular Cloning—A Laboratory Manual, Cold Spring Harbor Laboratory , Cold Spring Harbor, N.Y., (1989) or Current Protocols in Molecular Biology , Volumes 1-3, John Wiley & Sons, Inc. (1994-1998).
Using the sequences provided here, the isolation of DHAR nucleic acids the sequence provided here may be accomplished by a number of techniques. For instance, oligonucleotide probes based on the sequences disclosed here can be used to identify the desired gene in a cDNA or genomic DNA library. To construct genomic libraries, large segments of genomic DNA are generated by random fragmentation, e.g. using restriction endonucleases, and are ligated with vector DNA to form concatemers that can be packaged into the appropriate vector. To prepare a cDNA library, mRNA is isolated from the desired organ, such as flowers, and a cDNA library which contains the DHAR gene transcript is prepared from the mRNA. Alternatively, cDNA may be prepared from mRNA extracted from other tissues in which DHAR genes or homologs are expressed.
The cDNA or genomic library can then be screened using a probe based upon the sequence of a cloned DHAR gene disclosed here. Probes may be used to hybridize with genomic DNA or cDNA sequences to isolate homologous genes in the same or different plant species. Alternatively, antibodies raised against a DHAR polypeptide can be used to screen a mRNA expression library.
Alternatively, the nucleic acids of interest can be amplified from nucleic acid samples using amplification techniques. For instance, polymerase chain reaction (PCR) technology can be used to amplify the sequences of the DHAR genes directly from genomic DNA, from cDNA, from genomic libraries or cDNA libraries. PCR and other in vitro amplification methods may also be useful, for example, to clone nucleic acid sequences that code for proteins to be expressed, to make nucleic acids to use as probes for detecting the presence of the desired mRNA in samples, for nucleic acid sequencing, or for other purposes. For a general overview of PCR see PCR Protocols: A Guide to Methods and Applications. (Innis, M, Gleaned, D., Sninsky, J. and White, T., eds.), Academic Press, San Diego (1990).
Polynucleotides may also be synthesized by well-known techniques as described in the technical literature. See, e.g., Carruthers et al., Cold Spring Harbor Symp. Quant. Biol., 47:411-418 (1982), and Adams et al., J. Am. Chem. Soc., 105:661 (1983). Double stranded DNA fragments may then be obtained either by synthesizing the complementary strand and annealing the strands together under appropriate conditions, or by adding the complementary strand using DNA polymerase with an appropriate primer sequence.
DHAR nucleic acids of interest may also be identified by searching nucleic acid databases, e.g., EST databases and identifying sequences with high similarity to a known DHAR nucleic acid sequence. Once a candidate DHAR nucleic acid or polynucleotide sequence of the invention has been identified, standard methods can be used to determine if the putative nucleic acid is a DHAR nucleic acid of the invention. Methods of assaying for DHAR activity are known in the art, e.g., see example 1 and Hossain et al., Plant Cell Physiol. 25, 85-92.
Increasing DHAR Activity or Expression
Any of a number of means well known in the art can be used to increase DHAR activity in plants. Enhanced expression is useful for increasing levels of ASC in plants. For example, enhanced expression can be used to increase antioxidant activity and Vitamin C content in plants. Enhanced expression can be used to modulate the stomatal aperture. Increased levels of ASC in plants induces stomatal openings by scavenging hydrogen peroxide. Open stomatas support a greater exchange between plants and the environment providing for greater CO 2 assimilation and enhanced plant biomass.
Increasing DHAR Gene Expression
Isolated sequences prepared as described herein can be used to introduce expression of a particular DHAR nucleic acid to increase endogenous gene expression using methods well known to those of skill in the art.
One of skill will recognize that the polypeptides encoded by the genes of the invention, like other proteins, have different domains that perform different functions. Thus, the gene sequences need not be full length, so long as the desired functional domain of the protein is expressed. The distinguishing features of DHAR polypeptides are discussed below.
Modified protein chains can also be readily designed utilizing various recombinant DNA techniques well known to those skilled in the art and described in detail, below. For example, the chains can vary from the naturally occurring sequence at the primary structure level by amino acid substitutions, additions, deletions, and the like. These modifications can be used in a number of combinations to produce the final modified protein chain.
Other Means for Increasing DHAR Activity
One method to increase DHAR expression is to use “activation mutagenesis” (see, e.g. Hiyashi et al. Science, 258:1350-1353 (1992)). In this method an endogenous DHAR gene can be modified to be expressed constitutively, ectopically, or excessively by insertion of T-DNA sequences that contain strong/constitutive promoters upstream of the endogenous DHAR gene. As explained below, preparation of transgenic plants overexpressing DHAR can also be used to increase DHAR expression. Activation mutagenesis of the endogenous DHAR gene will give the same effect as overexpression of the transgenic DHAR nucleic acid in transgenic plants. Alternatively, an endogenous gene encoding an enhancer of DHAR activity or expression of the endogenous DHAR gene can be modified to be expressed by insertion of T-DNA sequences in a similar manner and DHAR activity can be increased.
Another strategy to increase DHAR expression can be the use of dominant hyperactive mutants of DHAR by expressing modified DHAR transgenes. For example expression of modified DHAR with a defective domain that is important for interaction with a negative regulator of DHAR activity can be used to generate dominant hyperactive DHAR proteins. Alternatively, expression of truncated DHAR proteins which have only a domain that interacts with a negative regulator can titrate the negative regulator and thereby increase endogenous DHAR activity. Use of dominant mutants to hyperactivate target genes is described in Mizukami et al., Plant Cell, 8:831-845 (1996).
Inhibition of DHAR Activity or Gene Expression
As explained above, DHAR activity is important in controlling ASC levels. In some embodiments, ASC levels are decreased, thereby increasing hydrogen peroxide levels and inducing stomatal closures. Inhibition of DHAR gene expression activity can be used, for instance, to increase drought tolerance by decreasing transpiration in transgenic plants or to decrease sensitivity to toxins by barring entry of toxins in transgenic plants. Targeted expression of DHAR nucleic acids that inhibit endogenous gene expression (e.g., antisense or co-suppression) can be used for this purpose.
Inhibition of DHAR Gene Expression
The nucleic acid sequences disclosed here can be used to design nucleic acids useful in a number of methods to inhibit DHAR or related gene expression in plants. For instance, antisense technology can be conveniently used. To accomplish this, a nucleic acid segment from the desired gene is cloned and operably linked to a promoter such that the antisense strand of RNA will be transcribed. The construct is then transformed into plants and the antisense strand of RNA is produced. In plant cells, it has been suggested that antisense suppression can act at all levels of gene regulation including suppression of RNA translation (see, Bourque Plant Sci . ( Limerick ) 105:125-149 (1995); Pantopoulos In Progress in Nucleic Acid Research and Molecular Biology , Vol. 48. Cohn, W. E. and K. Moldave (Ed.). Academic Press, Inc.: San Diego, Calif., USA; London, England, UK. p. 181-238; Heiser et al. Plant Sci. , (Shannon) 127:61-69 (1997)) and by preventing the accumulation of mRNA which encodes the protein of interest, (see, Baulcombe, Plant Mol. Bio., 32:79-88 (1996); Prins and Goldbach, Arch. Virol., 141:2259-2276 (1996); Metzlaff et al. Cell, 88 845-854 (1997), Sheehy et al., Proc. Nat. Acad. Sci. USA, 85:8805-8809 (1988), and Hiatt et al., U.S. Pat. No. 4,801,340).
The nucleic acid segment to be introduced generally will be substantially identical to at least a portion of the endogenous DHAR gene or genes to be repressed. The sequence, however, need not be perfectly identical to inhibit expression. The vectors of the present invention can be designed such that the inhibitory effect applies to other genes within a family of genes exhibiting identity or substantial identity to the target gene.
For antisense suppression, the introduced sequence also need not be full length relative to either the primary transcription product or fully processed mRNA. Generally, higher identity can be used to compensate for the use of a shorter sequence. Furthermore, the introduced sequence need not have the same intron or exon pattern, and identity of non-coding segments may be equally effective. Normally, a sequence of between about 30 or 40 nucleotides and about full length nucleotides should be used, though a sequence of at least about 100 nucleotides is preferred, a sequence of at least about 200 nucleotides is more preferred, and a sequence of about 500 to about 3500 nucleotides is especially preferred.
A number of gene regions can be targeted to suppress DHAR gene expression. The targets can include, for instance, the coding regions, introns, sequences from exon/intron junctions, 5′ or 3′ untranslated regions, and the like.
Another well known method of suppression is sense co-suppression. Introduction of nucleic acid configured in the sense orientation has been recently shown to be an effective means by which to block the transcription of target genes. For an example of the use of this method to modulate expression of endogenous genes (see, Assaad et al. Plant Mol. Bio., 22:1067-1085 (1993); Flavell, Proc. Natl. Acad. Sci. USA, 91:3490-3496 (1994); Stam et al. Annals Bot., 79:3-12 (1997); Napoli et al., The Plant Cell, 2:279-289 (1990); and U.S. Pat. Nos. 5,034,323, 5,231,020, and 5,283,184).
The suppressive effect may occur where the introduced sequence contains no coding sequence per se, but only intron or untranslated sequences homologous to sequences present in the primary transcript of the endogenous sequence. In one embodiment, the introduced sequence generally will be substantially identical to the endogenous sequence intended to be repressed. This minimal identity will typically be greater than about 65%, but a higher identity might exert a more effective repression of expression of the endogenous sequences. Substantially greater identity of more than about 80% is preferred, though about 95% to absolute identity would be most preferred. In another embodiment, the introduced sequence will have a region of 21 nucleotides with 100% identity to the endogenous sequence intended to be repressed. As with antisense regulation, the effect should apply to any other proteins within a similar family of genes exhibiting identity or substantial identity.
For co-suppression, the introduced sequence, needing less than absolute identity, also need not be full length, relative to either the primary transcription product or fully processed mRNA. This may be preferred to avoid concurrent production of some plants which are overexpressers. A higher identity in a shorter than full length sequence compensates for a longer, less identical sequence. Furthermore, the introduced sequence need not have the same intron or exon pattern, and identity of non-coding segments will be equally effective. Normally, a sequence of the size ranges noted above for antisense regulation is used. In addition, the same gene regions noted for antisense regulation can be targeted using co-suppression technologies.
Oligonucleotide-based triple-helix formation can also be used to disrupt DHAR gene expression. Triplex DNA can inhibit DNA transcription and replication, generate site-specific mutations, cleave DNA, and induce homologous recombination (see, e.g., Havre and Glazer, J. Virology, 67:7324-7331 (1993); Scanlon et al., FASEB J., 9:1288-1296 (1995); Giovannangeli et al., Biochemistry, 35:10539-10548 (1996); Chan and Glazer, J. Mol. Medicine ( Berlin ), 75:267-282 (1997)). Triple helix DNAs can be used to target the same sequences identified for antisense regulation.
Transposon insertions or tDNA insertions can be used to inhibit expression of DHAR genes. Standard methods are known in the art. Catalytic RNA molecules or ribozymes can also be used to inhibit expression of DHAR genes. For example, it is possible to design ribozymes that specifically pair with virtually any target RNA and cleave the phosphodiester backbone at a specific location, thereby functionally inactivating the target RNA. In carrying out this cleavage, the ribozyme is not itself altered, and is thus capable of recycling and cleaving other molecules, making it a true enzyme. The inclusion of ribozyme sequences within antisense RNAs confers RNA-cleaving activity upon them, thereby increasing the activity of the constructs. Thus, ribozymes can be used to target the same sequences identified for antisense regulation.
A number of classes of ribozymes have been identified. One class of ribozymes is derived from a number of small circular RNAs which are capable of self-cleavage and replication in plants. The RNAs replicate either alone (viroid RNAs) or with a helper virus (satellite RNAs). Examples include RNAs from avocado sunblotch viroid and the satellite RNAs from tobacco ringspot virus, lucerne transient streak virus, velvet tobacco mottle virus, solanum nodiflorum mottle virus and subterranean clover mottle virus. The design and use of target RNA-specific ribozymes is described in Zhao and Pick, Nature, 365:448-451 (1993); Eastham and Ahlering, J. Urology, 156:1186-1188 (1996); Sokol and Murray, Transgenic Res., 5:363-371 (1996); Sun et al., Mol. Biotechnology, 7:241-251 (1997); and Haseloff et al., Nature, 334:585-591 (1988).
Modification of Endogenous DHAR Genes
Methods for introducing genetic mutations described above can also be used to select for plants with decreased DHAR expression.
DHAR activity may be modulated by eliminating the proteins that are required for DHAR cell-specific gene expression. Thus, expression of regulatory proteins and/or the sequences that control DHAR gene expression can be modulated using the methods described here.
Another strategy is to inhibit the ability of a DHAR protein to interact with itself or with other proteins. This can be achieved, for instance, using antibodies specific to DHAR. In this method cell-specific expression of DHAR-specific antibodies is used to inactivate functional domains through antibody: antigen recognition (see, Hupp et al., Cell, 83:237-245 (1995)). Interference of activity of a DHAR interacting protein(s) can be applied in a similar fashion. Alternatively, dominant negative mutants of DHAR can be prepared by expressing a transgene that encodes a truncated DHAR protein. Use of dominant negative mutants to inactivate target genes in transgenic plants is described in Mizukami et al., Plant Cell, 8:831-845 (1996).
Preparation of Recombinant Vectors
To use isolated sequences in the above techniques, recombinant DNA vectors suitable for transformation of plant cells are prepared. Techniques for transforming a wide variety of higher plant species are well known and described in the technical and scientific literature. See, for example, Weising et al. Ann. Rev. Genet., 22:421-477 (1988). A DNA sequence coding for the desired polypeptide, for example a cDNA sequence encoding a full length protein, will preferably be combined with transcriptional and translational initiation regulatory sequences which will direct the transcription of the sequence from the gene in the intended tissues of the transformed plant.
For example, for overexpression, a plant promoter fragment may be employed which will direct expression of the gene in all tissues of a regenerated plant. Such promoters are referred to herein as “constitutive” promoters and are active under most environmental conditions and states of development or cell differentiation. Examples of constitutive promoters include the cauliflower mosaic virus (CaMV) 35S transcription initiation region, the 1′- or 2′-promoter derived from T-DNA of Agrobacterium tumafaciens , and other transcription initiation regions from various plant genes known to those of skill. Such genes include for example, ACT11 from Arabidopsis (Huang et al. Plant Mol. Biol., 33:125-139 (1996)), Cat3 from Arabidopsis (GenBank No. U43147, Zhong et al., Mol. Gen. Genet., 251:196-203 (1996)), the gene encoding stearoyl-acyl carrier protein desaturase from Brassica napus (Genbank No. X74782, Solocombe et al. Plant Physiol., 104:1167-1176 (1994)), GPc1 from maize (GenBank No. X15596, Martinez et al. J. Mol. Biol, 208:551-565 (1989)), and Gpc2 from maize (GenBank No. U45855, Manjunath et al., Plant Mol. Biol., 33:97-112 (1997)).
Alternatively, the plant promoter may direct expression of the DHAR nucleic acid in a specific tissue, organ or cell type (i.e. tissue-specific promoters, organ-specific promoters) or may be otherwise under more precise environmental or developmental control (i.e. inducible promoters). Examples of environmental conditions that may effect transcription by inducible promoters include anaerobic conditions, elevated temperature, the presence of light, or sprayed with chemicals/hormones. One of skill will recognize that an organ-specific promoter may drive expression of operably linked sequences in organs other than the target organ. Thus, as used herein an organ-specific promoter is one that drives expression preferentially in the target organ, but may also lead to some expression in other organs as well.
A number of tissue-specific promoters can also be used in the invention. For instance, promoters that direct expression of nucleic acids in guard cells are useful for conferring drought tolerance. One such particularly preferred promoter is KAT1, which has been shown in transgenic plants to drive expression primarily in guard cells (see, Nakamura, R., et al., Plant Physiol., 109:371-374 (1995). Another particularly preferred promoter is the truncated 0.3 kb 5′ proximal fragment of potato ADP-glucose pyrophosphorylase, which has been shown to drive expression exclusively in guard cells of transgenic plants. See, e.g., Muller-Rober, B., et al., Plant Cell, 6:601-612 (1994).
If proper polypeptide expression is desired, a polyadenylation region at the 3′-end of the coding region should be included. The polyadenylation region can be derived from the natural gene, from a variety of other plant genes, or from T-DNA.
The vector comprising the sequences (e.g., promoters or coding regions) from genes of the invention will typically comprise a marker gene that confers a selectable phenotype on plant cells. For example, the marker may encode biocide resistance, particularly antibiotic resistance, such as resistance to kanamycin, (G418, bleomycin, hygromycin, or herbicide resistance, such as resistance to chlorosulfuron or Basta. The present invention also provides promoter sequences from the DHAR gene (SEQ ID NO: 3), which can be used to direct expression of the DHAR coding sequence or heterologous sequences in desired tissues.
Production of Transgenic Plants
DNA constructs of the invention may be introduced into the genome of the desired plant host by a variety of conventional techniques. For example, the DNA construct may be introduced directly into the genomic DNA of the plant cell using techniques such as electroporation and microinjection of plant cell protoplasts, or the DNA constructs can be introduced directly to plant tissue using biolistics, e.g., DNA particle bombardment.
Microinjection techniques are known in the art and well described in the scientific and patent literature. The introduction of DNA constructs using polyethylene glycol precipitation is described in Paszkowski et al. Embo J., 3:27 17-2722 (1984). Electroporation techniques are described in Fromm et al. Proc. Natl. Acad. Sci. USA, 82:5824 (1985). Biolistic transformation techniques are described in Klein et al. Nature, 327:70-73 (1987).
Alternatively, the DNA constructs may be combined with suitable T-DNA flanking regions and introduced into a conventional Agrobacterium tumefaciens host vector. The virulence functions of the Agrobacterium tumefaciens host will direct the insertion of the construct and adjacent marker into the plant cell DNA when the cell is infected by the bacteria. Agrobacterium tumefaciens -mediated transformation techniques, including disarming and use of binary vectors, are well described in the scientific literature. See, for example Horsch et al. Science, 233:496-498 (1984), and Fraley et al. Proc. Natl. Acad. Sci. USA, 80:4803 (1983) and Gene Transfer to Plants, Potrykus, ed. (Springer-Verlag, Berlin 1995).
Transformed plant cells which are derived by any of the above transformation techniques can be cultured to regenerate a whole plant which possesses the transformed genotype and thus the desired phenotype such as decreased farnesyltransferase activity. Such regeneration techniques rely on manipulation of certain phytohormones in a tissue culture growth medium, typically relying on a biocide and/or herbicide marker that has been introduced together with the desired nucleotide sequences. Plant regeneration from cultured protoplasts is described in Evans et al., Protoplasts Isolation and Culture, Handbook of Plant Cell Culture , pp. 124-176, MacMillilan Publishing Company, New York, 1983; and Binding, Regeneration of Plants, Plant Protoplasts , pp. 21-73, CRC Press, Boca Raton, 1985. Regeneration can also be obtained from plant callus, explants, organs, or parts thereof. Such regeneration techniques are described generally in Klee et al., Ann. Rev, of Plant Phys., 38:467-486 (1987).
The nucleic acids of the invention can be used to confer desired traits on essentially any plant. Thus, the invention has use over a broad range of plants, including species from the genera Anacardium, Arachis, Asparagus, Atropa, Avena, Brassica, Chlamydomonas, Chlorella, Citrus, Citrullus, Capsicum, Carthamus, Cocos, Coffea, Cucumis, Cucurbita, Cyrtomium, Daucus, Elaeis, Fragaria, Glycine, Gossypium, Helianthus, Heterocallis, Hordeum, Hyoscyamus, Lactuca, Laminaria, Linum, Lolium, Lupinus, Lycopersicon, Macrocystis, Malus, Manihot, Majorana, Medicago, Nereocystis, Nicotiana, Olea, Oryza, Osmunda, Panieum, Pannesetum, Persea, Phaseolus, Pistachia, Pisum, Pyrus, Polypodium, Prunus, Pteridium, Raphanus, Ricinus, Secale, Senecio, Sinapis, Solanum, Sorghum, Theobromus, Trigonella, Triticum, Vicia, Vitis, Vigna, and Zea . In particular, the invention is useful with any plant with guard cells.
One of skill will recognize that after the expression cassette is stably incorporated in transgenic plants and confirmed to be operable, it can be introduced into other plants by sexual crossing. Any of a number of standard breeding techniques can be used, depending upon the species to be crossed.
Using known procedures one of skill can screen for plants of the invention by detecting the increase or decrease of DHAR mRNA or protein in transgenic plants. Means for detecting and quantifying mRNAs or proteins are well known in the art, e.g., Northern Blots, Western Blots or activity assays. The plants of the invention can also be identified by detecting the desired phenotype. For instance, measuring stomatal apertures, Vitamin C content, drought tolerance, toxin tolerance and rates of CO 2 assimilation using methods as described below.
Detection of Transgenic Plants of the Invention
After preparation of the expression cassettes of the present invention and introduction of the cassettes into a plant, the resultant transgenic plants can be assayed for the phenotypical characteristics associated with increased or decreased DHAR expression. For example, after introduction of the cassette into a plant, the plants are screened for the presence of the transgene and crossed to an inbred or hybrid line. Progeny plants are then screened for the presence of the transgene and self-pollinated. Progeny from the self-pollinated plants are grown. The resultant transgenic plants can be assayed for increased drought tolerance, decreased sensitivity to toxins, increased cellular Vitamin C content, and increased CO 2 assimilation. For example, a transgenic plant can be assayed for increased drought tolerance. Methods for assaying for increased drought tolerance are known and include measuring transpiration rate of transgenic plants, stomatal conductance, rate of water loss in a detached leaf assay or examining leaf turgor. Transgenic plants with decreased transpiration rates, for example, have increased drought tolerance. In another embodiment of the present invention, transgenic plants can be assayed for decreased sensitivity to toxins using known methods. In one method, for example, transgenic plants overexpressing DHAR, transgenic plants co-suppressed for DHAR, and control plants are exposed to 160 parts per billion (ppb) ozone for 3 days, 7 hours a day and subsequently examined. Leaves of plants with sensitivity to toxins will show ozone induced damages such as necrosis, while leaves with decreased sensitivity will show less or no ozone-induced damage. In other embodiments, transgenic plants can be examined for enhanced biomass, yield and Vitamin C (ASC) content using standard techniques.
It is understood that the examples and embodiments described herein are for illustrative purposes only and that various modifications or changes in light thereof will be suggested to persons skilled in the art and are to included within the spirit and purview of this application and are considered within the scope of the appended claims. All publications, patents, and patent applications cited herein are hereby incorporated by reference in their entirety for all purposes.
EXAMPLE 1
Overexpression of DHAR
A full-length wheat DHAR cDNA was isolated following the screening of a wheat seedling cDNA expression library using anti-wheat DHAR antiserum. A full-length tobacco DHAR cDNA was isolated following the screening a tobacco seedling cDNA library using the wheat DHAR cDNA as the probe. Full-length ESTs for rice, tomato, and Arabidopsis were identified in GenBank. The sequence for a full-length maize DHAR was constructed from two partial ESTs (i.e., AW258053 and BE552888) that were identical in the region of overlap. The wheat DHAR cDNA was introduced into the E. coli expression vectors, pET19b and pET 11 (Novagen), which allowed expression of recombinant wheat DHAR with or without an N-terminal His-tag, respectively. The His-tagged wheat DHAR cDNA construct was introduced under the control of the CaMV 35S promoter in the binary vector, pBI101 (Clontech Laboratories, Inc.). The resulting construct was introduced into Agrobacterium tumefaciens strain LBA4404 which was used essentially as described (17) to obtain tobacco ( N. tabacum , cv. Xanthi) transformants expressing wheat DHAR.
To generate maize overexpressing the wheat DHAR, the DHAR coding region (without an N-terminal His-tag) was placed under the control of the maize ubiquitin (Ub) promoter in the vector, pACH18 (18). DHAR was also placed under the control of the maize Shrunken 2 (Sh2) promoter (amplified as a 1.5 kbp fragment from B73) which had been substituted for the ubiquitin promoter in pACH18. Each construct was introduced into embryogenic A188×B73 (HiII) maize callus using particle bombardment as described (19). Co-transformation with the bar gene provided bialaphos selection for the isolation of transformed callus used for regeneration (20). Regenerants containing the Sh2-DHAR or Ub-DHAR constructs were identified using PCR and DHAR expression confirmed by activity assay and Western analysis using anti-wheat DHAR antiserum. T 0 plants were crossed with HiII, transgene-containing progeny identified, and the T 1 plants selfed.
DHAR was purified to homogeneity from 10 day old wheat leaves and was used to raise anti-DHAR antiserum in rabbits. For Western analysis, a membrane containing the protein of interest was blocked for 30 min in TPBS (0.1% TWEEN 20, 13.7 mm NaCl, 0.27 mm KCl, 1 mm Na 2 HPO 4 , 0.14 mm KH 2 PO 4 ) with 5% reconstituted dry milk and incubated with anti-wheat DHAR (diluted 1:1000) in TPBS with 1% milk for 1.5 hrs. The blots were then washed with TPBS, incubated with goat anti-rabbit-horseradish peroxidase a antibody (Southern Biotechnology) diluted 1:5000 to 1:10,000 for 1 hr, and DHAR detected using chemilumensence (Amersham Corp).
DHAR activity was assayed as described in Hossain et al., Plant Cell physiol. 25, 85-92(1984). Soluble protein was extracted from tobacco leaves or maize kernels ground in liquid nitrogen before grinding in extraction buffer (50 mM Tris-HCl pH 7.4, 100 mM NaCl, 2 mM EDTA, 1 mM MgCl 2 ) and centrifugation twice at 13,000 rpm for 5 min to remove cell debris. Protein concentration was determined as described (22). DHAR activity was assayed from an equal amount of protein by adding extract in a reaction containing 50 mM K 2 HPO 4 /KH 2 PO 4 pH 6.5, 0.5 mM DHA, and 1 mM GSH. The activity of DHAR was followed by an increase in absorbance at 265 nm.
Ascorbic acid was determined as described in Foyer et al., Planta, 157, 239-244. Fresh leaves were ground in 2.5 M HClO 4 and centrifuged at 13,000 rpm for 10 min to remove cell debris. Two volumes of 1.25 M Na 2 CO 3 were added to the supernatant to neutralize it and the sample was centrifuged at 13,000 rpm for 5 min. Ascorbate was measured from the supernatant immediately by adding 100 ml of the sample to a reaction containing 895 ml 100 mM K 2 HPO 4 /KH 2 PO 4 pH 5.6. The amount of ascorbate was determined by the change in absorbance at 265 nm before and after the addition of 0.25 unit ascorbate oxidase to the reaction. A range of ascorbate concentrations was assayed to serve as standards. The total amount of reduced and oxidized ascorbic acid (i.e., AsA and DHA) was determined by reducing DHA to AsA (in a reaction containing 100 mM K 2 HPO 4 /KH 2 PO 4 pH 6.5, 2 mM GSH, and 0.1 mg recombinant wheat DHAR protein incubated at 25° C. for 20 min) prior to measuring ascorbic acid. The amount of DHA was determined as the difference between these two assays. GSH and GSSG were determined from fresh leaves as described (24).
DHAR Activity Declines With Leaf Age
Prior to an attempt to increase DHAR expression, it was necessary to determine the expression profile of DHAR during leaf development. For this purpose, tobacco was selected as a model species possessing a large leaf size that permits biochemical analysis of leaves from young and expanding to those that are pre-senescent. DHAR activity and protein was measured in individual leaves from an adult plant containing approximately 20 leaves in which the inflorescence had not yet emerged. DHAR activity was highest in young, expanding leaves and in the first fully-expanded leaf in which photosynthesis was highest. The level of DHAR declined thereafter as a function of leaf age. The decrease in DHAR activity was accompanied by a decrease in DHAR protein although to a lesser extent suggesting regulation of DHAR enzyme activity. Moreover, the decrease in DHAR activity preceded the onset of visible signs of leaf senescence, e.g., the loss of chlorophyll. These data illustrate that expression of DHAR activity and DHAR protein correlate with leaf age and function.
Isolation of cDNAs Encoding DHAR
With the exception of rice and spinach, DHAR cDNAs from plant species have not been reported. Consequently, cDNAs encoding DHAR were isolated from wheat and tobacco cDNA libraries. A full-length cDNA was isolated from a wheat cDNA library using anti-DHAR antiserum and this cDNA was used to screen a tobacco cDNA library. Full-length ESTs encoding DHAR were identified from tomato, Arabidopsis , and rice, and a full-length maize EST was reconstructed from two partial ESTs. The rice EST identified in this study was identical to that previously reported (see Urano et al., FEBS Lett., 4, 107-111). Comparison of the amino acid sequence predicted from each cDNA or EST revealed that DHAR is conserved in molecular weight (23, 358 Da for the wheat ortholog) and composition among plants (FIG. 2). Expression of wheat DHAR in E. coli as a N-terminal His-tagged protein exhibited substantial DHAR activity (9.1 mmol/min/mg) and was approximately 40% as active as wheat DHAR without a His-tag (23 mmol/min/mg) when an equal amount of each protein from E. coli extract was assayed.
Overexpression of DHAR in Leaves
In order to generate tobacco with altered DHAR expression, the His-tagged wheat DHAR cDNA was placed under the control of the CaMV 35S promoter in the binary vector, pBI101, which was subsequently introduced into tobacco. Regenerants screened for expression of wheat DHAR identified multiple individuals that overexpressed the transgene. Analysis of DHAR expression from leaves of three representative transgenic T 1 progeny revealed substantial overexpression of the wheat DHAR transgene. The presence of the N-terminal His-tag resulted in a transgenic DHAR of larger molecular weight that allowed the extent of its expression to be distinguished from expression of the endogenous tobacco DHAR. The expression of wheat DHAR appeared as two bands where the lower one corresponds to the recombinant His-tagged form, suggesting that the upper band may be modified in a way that retards its migration. Overexpression of the wheat DHAR transgene did not alter expression of the endogenous tobacco DHAR. Overexpression of the wheat DHAR protein was accompanied by a substantial increase in DHAR activity in the transgenic leaves. Because DHAR expression declines with increasing leaf age, DHAR activity was measured in young, mature, and pre-senescent leaves of three transgenic individuals. As observed for the endogenous DHAR, the level of wheat DHAR activity declined with leaf age, however, overexpression of wheat DHAR resulted in up to an 11-fold increase in DHAR activity in young, expanding leaves, up to a 13-fold increase in mature leaves, and up to a 32-fold increase in pre-senescent leaves relative to control tobacco. Expression of the wheat DHAR did not affect the rate of growth or timing of flowering of the transgenic tobacco.
Increasing DHAR Activity Results in Increased Ascorbic acid and Glutathione Content
To determine the metabolic consequences of DHAR overexpression, the level of its substrate, i.e., DHA, and its product, i.e., AsA, were measured in DHAR-overexpressing and control plants. Because DHAR activity declined with leaf age, the level of AsA was measured in young, mature, and pre-senescent leaves. The level of AsA was elevated up to 2.4-fold in young, expanding leaves, up to 3.9-fold in mature leaves, and up to 2.2-fold in pre-senescent leaves. Concomitant with the increase in ascorbic acid, a decrease in DHA was detected in young, expanding leaves which, together with the increase in AsA, resulted in a substantial change in the redox state from a ratio of AsA to DHA from 1.5 in control leaves to 4.8 in leaves overexpressing DHAR. Increases in the AsA to DHA ratio were observed in older leaves as well.
Because GSH is used as the reductant by DHAR to reduce DHA to AsA, the level of reduced and oxidized glutathione was measured in the same leaves. The level of GSH was elevated up to 2.6-fold in young, expanding leaves, up to 2.0-fold in mature leaves, and up to 1.9-fold in pre-senescent leaves (FIG. 5). The redox status of glutathione increased in young leaves but was little changed in older leaves. Consequently, the overexpression of wheat DHAR resulted in an elevation in the absolute level of ascorbic acid and reduced glutathione as well as a substantial change in the redox state of leaves.
To examine whether increasing the expression of DHAR in a non-photosynthetic organ of a crop species would result in an increase in ascorbic acid content, the wheat DHAR coding region (without an N-terminal His-tag) was placed under the control of the maize ubiquitin (Ub) promoter in the vector, pACH18 (18). DHAR was also placed under the control of the maize Shrunken 2 (Sh2) promoter which had been substituted for the Ub promoter in pACH18. Regenerants containing the Sh2-DHAR or Ub-DHAR constructs following particle bombardment of embryogenic Hill callus were identified using PCR and confirmed by DHAR activity assay as well as Western analysis. T 1 progeny from a cross between T 0 plants and Hill were then grown and progeny from self-pollinated T 1 plants used for ascorbic acid measurements. Ascorbic acid from grain of plants containing just the Ub-DHAR construct, just the Sh2-DHAR construct, or both constructs was measured. Grain not containing either transgene had little endogenous DHAR activity and protein, suggesting that recycling of ascorbic acid may not occur at a high rate in maize grain. In grain expressing wheat DHAR (calculated MW of 23,358 kD), the transgenic protein co-migrated with the endogenous maize DHAR (calculated MW of 23,328 kD). High overexpression of DHAR resulted in up to a 2.7-fold increase in the level of ascorbic acid. This increase was observed for plants expressing DHAR from the Ub and/or Sh2 promoters. Expression of DHAR to moderate levels in each transgenic line resulted in smaller increases in ascorbic acid content. These data demonstrate that the level of ascorbic acid can be increased in a non-photosynthetic organ as well as in a photosynthetic organ such as leaves.
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The invention is directed to a new dehydroascorbate reductase (“DHAR”) genes from Triticum aestivum, which is useful in modulating ascorbic acid levels in plants.
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CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] This application claims the benefit of German patent application 10 2005 059 078.0, filed Dec. 10, 2005, and corresponding International PCT Application No. PCT/EP2006/010502, each herein incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to a method for piecing a yarn at a rotor spinning machine and to a rotor spinning machine for carrying out such method.
[0003] With increasing demands on the yarn production process, ever higher demands are also made on the production of piecers. The process of forming piecers after yarn interruptions, the piecing, is carried out at the individual spinning stations of the open-end rotor spinning machines, generally by a piecing unit travelling along the spinning machine, the so-called piecing carriage. The piecing process is controlled by means of a piecing program.
[0004] The quality of piecers with regard to their visual appearance and strength is decisively influenced by an optimal parameterisation of the piecing program. The very complex process for determining the optimal piecing parameters until now has had to be carried out after every batch change and every change of spinning parameters, such as, for example, a change in the draft, the twist factor, the rotor speed and the like. An adequately good adjustment can often only be found after hours even with experienced users. This task is made more difficult when spinning fine yarns with high yarn counts. In the case of small yarn diameters, for example 0.2 mm with a yarn count Nm 50, it is no longer possible without a mechanical visual display of the yarn diameter for the user to visually detect the fluctuations occurring in the 100 th of a millimeter range.
[0005] An important reason for the outlay for optimisation is due to the circumstance that during piecing, the fiber flow is only available in a delayed manner and not 100%. This is to be attributed to the procedure in principle during piecing.
[0006] Thus, after a process triggering the piecing, such as, for example, a yarn break or a bobbin change, the yarn band feed is switched off. The trailing opening roller, however, still releases fibers from the fiber tuft. In order to achieve the same conditions and therefore a prefeed quantity which is as far as possible the same, before each piecing process, the fiber tuft is evened out. Up to the piecing, fibers continue to be combed from the fiber tuft, so the fiber tuft is shortened.
[0007] The prefeed to form a fiber ring takes place for a predetermined time and is then switched off. In this case, the quantity of fed-in fibers as well as the duration of the prefeed can also be controlled by the adjustment of the feed speed. The process of piecing begins with the rotor start. On reaching a preadjusted piecing rotor speed, feeding in of fibers begins. In this case, a certain delay occurs in reaching the required fiber flow and possibly causes a diameter deviation after the piecer. Therefore, the fiber feed is already switched on again shortly before the start of the yarn draw-off. The draw-off speed then has a value which corresponds to the instantaneous rotor speed when maintaining the desired twist of the spun yarn. Until the operating rotor speed is reached, the draw-off speed follows the increase in the rotor speed.
[0008] Apart from the follow-up movement of the fiber flow after switching off the feed and the delayed starting up after switching on the feed, the fiber flow can also react with a delay when increasing the feed speed. This can lead to diameter fluctuations of the yarn occurring after the piecer. In order to avoid these undesired diameter fluctuations, a so-called feed addition is carried out.
[0009] When piecing, it is attempted by means of the feed addition to ensure that 100% of the required quantity of fiber is present in the rotor at every draw-off instant. The feed addition thus compensates the temporary shortfall quantity through a higher feed speed. A linear increase in the fiber flow is assumed here. The optimisation of the piecer inter alia assumes knowledge of the parameters: addition length, addition quantity and advance time of the feed, the necessary advance time of the feed being assumed to be constant with a predetermined spinning geometry. One is in a position to determine the addition length owing to suitable technical aids and the use of software for visually displaying the piecer profile.
[0010] A piecing mechanism is known from German Patent Publication DE 199 55 674 A1 set up for determining the length of the feed addition required to compensate the diameter deviation from the determined length of the diameter deviation. For this purpose, a predeterminable number of test piecers is produced without feed addition, but with reduced drafting, the number of which is determined as a function of the level of the nominal drafting.
[0011] German Patent Publication DE 199 55 674 A1 proceeds from a prior art, in which the yarn diameter in the region of the piecer is also evaluated. However, a feed addition is worked with there from the start in order to obtain, as far as possible from the beginning, piecers which can at least be used. An empirical value is used as the starting point for the addition, and is based on the average staple length. In the case of staple length distributions of natural fibers, which correspondingly fluctuate this leads in the first place to a relatively high degree of imprecision. A longer optimisation phase follows this first piecer, in which additional influences, such as the opening roller clothing, opening roller speed, rotor run-up time etc. are to be compensated and this makes the empirical determination relatively protracted. Furthermore, the result of this optimisation is only to some extent satisfactory with a very high outlay.
[0012] In contrast, German Patent Publication DE 199 55 674 A1 provides an algorithm, by means of which the length of the thin point is determined with the aid of test piecers which are produced without feed addition. So that these test piecers can be produced at all with a definite thin point at the end of the piecer, the draft is reduced for these test spinners to obtain a pieceable yarn end. This draft reduction has again to be calculated by a suitable algorithm to obtain the actual values for the thin point.
[0013] The basic information of German Patent Publication DE 199 55 674 A1 is that exclusively the length of the thin point is to be used to determine the feed addition. For this purpose, an average test piecer is calculated from a large number of individual test piecers and the increase in the yarn thickness is represented by a straight line, the point of intersection of which with the horizontal representing the normal yarn thickness is to embody the end of the thin point. The distance between the beginning of the piecer and this point of intersection is then defined as the addition length and the addition is then determined. This solution is clearly an improvement compared to the previously characterised prior art but is in need of improvement with regard to approaching the optimum of the piecer. The necessary addition level to determine the feed addition then has to be determined empirically however, which is liable to undesired imprecisions.
[0014] Because of the imprecisions occurring, the result of these measurements cannot, however, be transferred to other machines provided to process the same fiber band material and to adjust the piecing parameters.
[0015] Alternatively, the determination of the fiber flow behaviour may take place under laboratory conditions by means of video recordings of the fiber flow in the fiber guide channel. The high technical outlay does not allow this method to be used at every machine. Furthermore, the determination of the fiber flow behaviour has to be carried out again at each change of the fiber band.
[0016] Moreover, the actual effects of the fiber flow behaviour on the yarn are not detected with the two methods as the fiber flow cannot be determined at the site of the yarn formation because the interior of the rotor is not accessible for measurement purposes during operation. In addition, the two methods disregard the doubling back taking place in the rotor.
SUMMARY OF THE INVENTION
[0017] The invention is therefore based on the object of providing a method for piecing the yarn, by means of which the parameterisation of a spinning process is simplified, as well as to proposing a rotor spinning machine, which is set up to carry out the method.
[0018] This object is achieved according to the invention by a method for piecing a yarn at a rotor spinning machine comprising a plurality of spinning stations, in which a fiber band is supplied by a fiber band feed from a band supply, is opened by means of an opening mechanism and is supplied as a single fiber flow to the spinning rotors, and in which the yarn spun in the spinning rotor is drawn off by a draw-off device from the spinning rotor. At least one control device for detecting and evaluating data from an automatic piecing process is provided at least one spinning station. As well, at least one sensor device for measuring the yarn diameter and for detecting the position of the associated measuring point of a piecer produced during the piecing process is provided at least one spinning station. The successive production of a plurality of piecers is controlled by means of the control device in a measuring phase without feed addition and with reduced drafting. The method of the present invention is characterised by successively producing more than five piecers in the measuring phase and the coordinates of the measurement values together with the associated measurement values from the individual measurements of the piecers are supplied for an evaluation for averaging and for determining a fiber band function taking into account the drafting reduced for the measurement values, which reflects the fiber flow behaviour in the form of the respective fiber band quantity supplied to the rotor as a function of the transport path of the fiber band feed. The speed of the fiber band feed is controlled in a delayed manner from the run-up of the yarn draw-off, which is dependent on the rotor speed, by means of the fiber band function, in such a way that the fiber shortfall quantity being produced from the fiber band function is compensated by dynamic feed addition with respect to height and length.
[0019] The invention also provides a rotor spinning machine for carrying out the above-described method, with a plurality of spinning stations, at least one control device for detecting and evaluating data of an automatic piecing process at least one spinning station as well as at least one sensor device for measuring the yarn diameter and for detecting the position of the associated measurement point of a piecer produced during the piecing process. The textile machine has a control device which is set up to control the successive production in a measuring phase of a plurality of piecers without a feed addition and with reduced drafting. The rotor spinning machine is characterised in that the control device is set up to automatically carry out the measuring phase and for evaluation and averaging to determine the fiber band function.
[0020] According to the present method, it is provided that in the measuring phase, successively more than five piecers are produced, in that the coordinates of the measurement values together with the associated measurement values from the individual measurements of the piecers are supplied for evaluation to average and to determine a fiber band function taking into account the reduced drafting for the measurement values, which reflects the fiber flow behaviour in the form of the fiber band quantity supplied in each case to the rotor as a function of the transport path of the fiber band feed, and in that the speed of the fiber band feed is controlled in a delayed manner by means of the fiber band function from the run-up of the yarn draw-off which is dependent on the rotor speed, in such a way that the shortfall quantity of fiber produced from the fiber band function is compensated by dynamic feed addition with respect to height and length.
[0021] The fiber band function determined after the measuring phase allows determination of the fiber band weight available for each feed path and the instantaneous speed of the feed produced from this feed path in any desired combinations of adjustments of the spinning parameters. In this case, the fiber band function determined according to the invention takes into account the fiber flow behaviour subject to a series of influences, the main influence of which is produced from the natural shortwave and longwave scatterings of the fiber band and has an effect in the point of origin of the yarn, in the spinning rotor. The determination of the fiber band function can substantially simplify the parameterisation of the piecing process as the fiber flow behaviour decisively influencing the piecing process is taken into account by this function. Staff who are trained in a certain manner and are experienced and have to empirically determine the parameters, or the requirement for expensive laboratory investigations and measuring equipment to determine the parameters, such as is necessary in the prior art, are unnecessary. A high quality of the piecer is achieved by the dynamic feed addition of the missing fiber band quantity which depends on the course of the fiber band function. The fiber band function describes the fiber flow behaviour at the site of the yarn formation, in the rotor, and takes into account the doubling back taking place in the rotor of the yarn being formed.
[0022] Moreover, a fiber band characteristic value can be calculated from the fiber band function and is independent of a variation of the spinning parameters and/or spinning means and reflects the fiber flow behaviour. The fiber band characteristic value is used for a simplified description of the fiber band function. A renewed calculation of the fiber band characteristic value or determination of the fiber band function therefore is only necessary upon a fiber band change as a result of a batch change with a different fiber band material as the fiber flow behaviour can change as a function of the fiber band material used. If only the spinning parameters and/or the spinning means, such as, for example, the rotor, the opening roller speed, the twist factor or the draft are changed, without changing the fiber band material, a repetition of the determination of the fiber band function is no longer necessary as the fiber band characteristic value or the fiber band function also retains its validity for changed spinning parameters, such as the draft, the rotor speed, the twist factor and the like. Owing to automation of the determination of the fiber flow behaviour and the determination of the fiber band function or the fiber band characteristic value describing this, it can also be made possible for inexperienced operating staff to produce piecers of high quality without having to carry out a complex optimisation phase. Only one process has to be initiated which carries out the determination of the fiber band function. By producing the yarn profile of an averaged piecer the determination of a reliable fiber band characteristic value can be achieved even after a few piecers to be produced in the measuring phase.
[0023] The time delay between the yarn draw-off and the fiber band feed, which is produced from the geometric structure of the assemblies involved in the spinning process, can be determined by measurement. In this case, the speed courses of the feed drive and the draw-off drive can be synchronised during the measuring phase taking into account the draft. As a result, the influence of the delay occurring when switching on the drive of the fiber band feed is taken into account. The speed of the feed drive is calculated as a function of the rotor speed at the instant of the draw-off, the rotation and the draft. To determine the rotor speed at the instant of the draw-off, the measured speed increase of the rotor during the run-up can be used.
[0024] In particular, the reduced draft in the measuring phase should be selected such that the diameter of the spun yarn is not less than 70% of the averaged yarn diameter. This ensures that the diameter deviations produced in the measuring phase after the piecer has an adequate characteristic and allow suitable assessment of the averaged piecer profile from the piecers. Drafts which are too great would lead to a flat rise in the piecer profile after the thin point of the averaged piecer and make piecing more difficult, while in the case of drafts which are too small, the rise lies within the first rotor periphery and therefore the rise in the piecer profile after the thin point of the averaged piecer is concealed thereby. The spinning drafts are preferably halved.
[0025] Furthermore, the piecers produced in the measuring phase should be discarded. For this purpose, the piecers produced during the measuring phase can be extracted by a suction device after they have been detected. This ensures that the piecers produced in the measuring phase with the reduced draft do not arrive on the cross-wound bobbin to be produced. Alternatively, the piecers produced during the measuring phase can be unwound from the bobbin before the next piecing process.
[0026] Furthermore, the sensor device can be calibrated before each piecing process. In this manner, external influences caused, for example, by finish or fine dust and the like which influence the measuring precision in the form of a basic shading, can be taken into account.
[0027] In particular, a yarn length should be measured in the measuring phase for the respective piecer, which, as a function of the selected draft, corresponds to a minimum fiber band length. This is used to detect all the fluctuations occurring of the yarn diameter, for example thick and thin points of the yarn, which can be caused by the natural diameter fluctuations of the fiber band, or the like, over a yarn length, which, because of the selected draft corresponds to a certain fiber band feed.
[0028] The fiber band function can preferably be defined as an exponential function, in particular as an e-function. The exponential function used as a basis to describe the fiber band function more precisely reflects the course of the yarn profile of the averaged piecer than the linearisation carried out according to the prior art of the yarn diameter deviation in the region after the piecer, and is therefore more suited to describe the fiber flow behaviour.
[0029] In an advantageous development of the method according to the invention, the fiber band function can be calculated to compensate yarn diameter fluctuations as a function of various threshold values.
[0030] According to the rotor spinning machine of the invention, it is proposed that the control device should be set up to carry out the measuring phase and the evaluation to average and determine the fiber band function. The degree of automation for the automatic piecing can be increased by the control device according to the invention. In addition, the parameterisation of the piecing process is simplified and can be carried out more rapidly compared to the prior art.
[0031] For this purpose, the at least one spinning station can be designed as a pilot spinning station set up to carry out the method, which is used to determine the fiber band function on a change in the fiber band used. At the pilot spinning station, the fiber band function can be determined for a pending batch change, in which a fiber band is used with different properties to the fiber band processed up until then. The piecing parameters are determined from the fiber band function determined for the fiber band or from the fiber band characteristic value describing this and then passed to the spinning stations, at which the new fiber band is to be processed. An individual spinning station for the entire rotor spinning machine and also one spinning station per section of the rotor spinning machine may be designed as a pilot spinning station.
[0032] Owing to the automation of the determination of the fiber flow behaviour and the calculation of the fiber band characteristic value describing the fiber band function it is also made possible for inexperienced staff to produce piecers of high quality without having to carry out a complex optimisation phase. A process merely has to be initiated at the control device which carries out the automatic determination of the fiber band function. A reliable fiber band function or a fiber band characteristic value describing this can be determined after a few piecers to be produced in the measuring phase, owing to the automatic production of the yarn profile of an averaged piecer.
[0033] To carry out the method according to the invention, the control device can control the measurement and averaging of the reference yarn. The reference yarn diameter determined in this manner is used as a basis for standardising the yarn diameter of the piecers measured in the subsequent measuring phase. Thus, in the measuring phase, a reference yarn diameter to be used as a basis to calculate the fiber band characteristic value is present and is used as a basis in assessing the yarn diameter deviation during piecing. Furthermore, the control device can control the measurement, evaluation and averaging of the yarn diameters of the at least five piecers produced in the measuring phase. Thus, the acquiring, evaluation and processing of the data determined takes place at a central location of the rotor spinning machine.
[0034] The control device may preferably be connected to a control mechanism of the respective spinning station by means of an operative connection, for example in the form of a bus system or by means of wirelessly communicating mechanisms. Furthermore, the rotor spinning machine may comprise at least one piecing mechanism, in which the control device is integrated. Alternatively, each spinning station may comprise a piecing mechanism, in which the control device is integrated.
BRIEF DESCRIPTION OF THE DRAWINGS
[0035] Further details of the invention are described with the aid of views of the figures, in which:
[0036] FIG. 1 shows a simplified schematic view of a spinning station of an open-end rotor spinning machine;
[0037] FIG. 2 shows an averaged piecer profile from a plurality of piecers;
[0038] FIG. 3 shows the averaged piecer profile according to FIG. 2 with different tan values drawn therein;
[0039] FIG. 4 shows the course of a fiber band characteristic value for the averaged piecer profile;
[0040] FIG. 5 shows a course of a fiber band function for the averaged piecer profile.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0041] FIG. 1 schematically shows a side view of one half of an open-end rotor spinning machine producing cross-wound bobbins.
[0042] Rotor spinning machines of this type have, as known, between their end frames (not shown), a large number of similar spinning stations 1 , the components of which are driven by a single motor. The spinning station 1 has an opening device 2 , into which a fiber band 5 is introduced by means of the feed roller 4 . The feed roller 4 is driven by a continuously adjustable feed motor 3 . The fiber band 5 is fed to an opening roller 7 rotating in the housing 6 and driven by a single motor and which opens the fiber band 5 supplied into individual fibers 8 .
[0043] The separated fibers 8 arrive through the fiber guide channel 9 onto the conical slip face 10 of a spinning rotor and from there into the fiber collecting groove 12 . From the fiber collecting groove 12 , the spun yarn 16 is drawn through the fiber draw-off tube 17 in the direction of the arrow 18 with the aid of a draw-off mechanism 19 . The spinning rotor 11 is fastened on a shaft 13 which is preferably configured as an external rotor of a single motor drive 14 .
[0044] The draw-off mechanism 19 for the spun yarn 16 has a pair of rollers, between which the yarn 16 to be drawn off is guided. During the normal spinning operation, the yarn 16 after the draw-off mechanism 19 follows the dashed line 15 and is then wound onto a cross-wound bobbin, not shown here. For automatic piecing, a piecing unit which can be moved along the rotor spinning machine is delivered to the spinning stations 1 and carries out the automatic piecing process. The piecing unit is not shown in more detail here for reasons of simplification. In an alternative embodiment of the rotor spinning machine, it is provided that each spinning station has suitable mechanisms which carry out the automatic piecing without the use of one or more movable piecing units being necessary.
[0045] After completion of the piecing process, it can be checked whether proper piecing has taken place. For this purpose, the yarn 16 is guided section-wise in the piecing unit, which is indicated schematically by the yarn deflection between the draw-off mechanism 19 and a yarn guide 20 . The yarn 16 in this case runs in the piecing unit, not shown in more detail, between two further yarn guides 21 and 22 through a sensor device 23 , with which the yarn diameter is continuously measured during the piecing process. The test signals for the length-related yarn diameter measurement values are supplied to a control device 24 of the piecing unit. A clearer 25 is arranged in the yarn course downstream from the yarn guide 20 . The clearer 25 comprises a sensor device 23 which monitors the occurrence of diameter fluctuations of the yarn 16 and if necessary emits a yarn interruption signal. If a yarn interruption signal is emitted by the clearer 25 this leads to a feed interruption of the fiber band 5 .
[0046] In an alternative embodiment, the clearer 25 and the sensor device 23 can be configured as an assembly belonging together, which is provided at each spinning station 1 . The arrangement of this assembly may preferably be provided in the region between the yarn draw-off tube 17 and the draw-off mechanism 19 . The spun yarn 16 is held under tension by the draw-off mechanism 19 , so a precise measurement of the yarn diameter is ensured.
[0047] The checking of the yarn diameter takes place during the run-up of the spinning rotor 11 at the accelerated yarn 16 . After the piecing, the yarn 16 , in accordance with the increasing spinning rotor speed, is drawn off at an increasing speed from the yarn draw-off tube 17 by means of the draw-off mechanism 19 . So that the measurement frequency of the sensor device 23 can be adjusted to the changing speed of the accelerating yarn 16 , pulses are picked up by means of a sensor 27 from the yarn draw-off roller of the draw-off mechanism 19 driven by a drive 26 . These pulses provide information about the draw-off speed and the length of the yarn 16 . The sensor signals are supplied to the control device 24 which controls the measurement frequency of the sensor 27 and adapts it to the yarn draw-off speed. The yarn draw-off speed can alternatively, for example, be determined by a contactless measurement directly at the yarn 16 . The control device 24 is connected to a control mechanism 28 of the spinning station 1 . The control mechanism 28 is connected via the line 29 to further modules of the rotor spinning machine.
[0048] The process of automatic piecing assumes an optimal parameterisation of the piecing program to be worked by the piecing unit. To simplify and automate the process of parameterisation, according to the invention, a fiber band function, which describes the fiber flow behaviour, is determined for automatic parameterisation, the flow behaviour being influenced mainly by the natural shortwave and longwave scatterings of the fiber band 5 . The fiber band function reflects the fiber flow behaviour in the form of the fiber band quantity supplied in each case to the spinning rotor 11 as a function of the transport path of the fiber band feed.
[0049] To determine the fiber band function describing the fiber flow behaviour, a yarn length of at least 400 m is firstly spun in advance in a test phase. The yarn diameter is measured via this yarn length by the sensor mechanism 23 and passed to the control device 24 .
[0050] An average is formed from the measurement values for the yarn diameters determined in the test phase and is used for further assessment as the reference yarn diameter. The reference yarn diameter which represents a yarn diameter of 100% is used for standardisation of subsequently measured yarn diameters. For the required piecer of the reference yarn to be produced, the feed addition is adjusted during the test phase in a manner known from the prior art (Raasch et al “Automatisches Anpinnen beim OE-Rotorspinnen”, Melliand Textilberichte 4/1989, pages 251 to 256).
[0051] The following measuring phase is carried out without feed addition in contrast to the preceding test phase. To allow the piecing without feed addition, the draft is reduced, wherein the yarn diameter of the diameter deviation produced after the piecer should not be less than 70% of the reference yarn diameter. In the present embodiment, the draft is reduced by 50% in that the feed speed of the fiber band 5 is doubled.
[0052] To ensure that with the beginning of the yarn draw-off the required yarn quantity for piecing is always available in the spinning rotor 11 the feed has to be in advance of the draw-off by a defined time span. The course of the run-up function of the feed motor 3 virtually precisely follows the course of the run-up function of the drive 26 of the draw-off mechanism 19 . In order to ensure the coinciding speed course and the preciseness connected therewith of the following measurements in the measuring phase, the speeds of the feed motor 3 and the drive 26 are synchronised. The feed speed f eed is calculated according to the formula:
[0000]
f
eed
=
n
rotor
rotation
*
draft
.
[0053] Here, the “rotation” describes the number of rotations on 1 metre of yarn 16 and n rotor describes the rotor speed at the instant of the draw-off. The calculation of the feed speed v feed therefore assumes knowledge of the rotor speed n rotor(start draw-off) at the instant of the draw-off of the yarn 16 . The rotor speed n rotor(start draw-off) is determined by a calculation of the rotor speed to be expected as a function of the speed increase according to the following formula:
[0000] N rotor(start draw-off) =n rotor(start feed) +( n rotor(increase) *advance time).
[0054] Here, n rotor(start draw-off) reflects the rotor speed to be determined at the instant at the beginning of the draw-off, n rotor(start feed) reflects the rotor speed at the instant of the beginning of the feed and n rotor(increase) describes the increase in the rotor speed over the time period of the run-up of the spinning rotor 11 until the operating speed is reached. The advance time gives the time span by which the feed motor 3 has to be in advance of the drive 26 of the draw-off mechanism 19 to provide fiber material for the piecer.
[0055] Before the beginning of the measuring phase and after each completed measurement during the measuring phase, a calibration of the sensor mechanism 23 is carried out. This takes place in such a way that a measurement is carried out with the sensor device 23 without the yarn 16 being supplied thereto to thus determine the existing basic shading due to the finish or other impurities, such as fine dust particles and the like. In this manner, the influences influencing the measurement result are taken into account during the subsequent measurements of the yarn diameter by means of the sensor device 23 .
[0056] To carry out the measuring phase described below, the drive of the cross-wound bobbin to be wound and the yarn guide 20 are put out of operation. The piecers produced in the measuring phase and the yarn lengths following the piecers are guided away via the yarn draw-off tube 17 . In this manner it is ensured that the yarn 16 which is newly spun during the measuring phase with half the yarn count is not used as piecing yarn.
[0057] The measuring phase begins with the start of drawing off the yarn 16 when the rotor 11 has reached the minimum speed required for piecing. In this case, about 7 metres of the yarn 16 are spun and the yarn diameter thereof recorded by the sensor device 23 . The averaged measurement values of the yarn diameters of the measuring phase are then standardised in each case by means of the reference yarn diameter already determined in the test phase.
[0058] The total measuring phase is repeated at least 5 times to be able to determine a significant fiber band function. From the recorded and standardised yarn diameter values of the piecers, an averaged piecer is formed. For further evaluation, the yarn length before the averaged piecer remains disregarded and does not enter the subsequent determination of the fiber band function. For evaluation, a yarn profile is now used which begins with the averaged piecer, as shown in FIG. 2 .
[0059] The averaged piecer, in its course of the yarn profile, has a clear diameter deviation, from the course of which the fiber band function describing the fiber flow behaviour is calculated below. The course of the yarn profile of the averaged piecer in the region of the diameter deviation can be represented substantially by the course of an exponential function, in particular an e-function. FIG. 5 shows the course of the yarn profile of the averaged piecer and the course of the corresponding fiber band function.
[0060] To determine the fiber band function, firstly the X and Y coordinate of the minimum value of the yarn profile of the averaged piecer is determined. The calculation of threshold values Y for various percentage deviations of the reference yarn diameter then takes place. The threshold values Y represent various percentage yarn diameters as a function of various tau values. The tau values describe the course of the exponential function for a value range of tau=1 to 5. Thus the value tau=1 corresponds to the reaching of a yarn diameter of 63%. The calculation of the threshold value Y takes place according to the following formula:
[0000] Y (tau)=(1− e −tau )*yarn average rotor run-up .
[0061] The value for the yarn average rotor run-up is produced from the averaged yarn diameter which is measured at the end of the rotor run-up in the measuring phase and is related to the standardisation to the reference yarn diameter. The calculation takes place according to the formula:
[0000]
Yarn
average
rotor
run
-
up
=
averaged
thread
diameter
after
rotor
run
-
up
reference
thread
diameter
.
[0062] After the threshold values Y have been calculated for various values of tau, the calculated threshold values Y are compared with the actual course of the yarn profile of the averaged piecer. For this purpose, in the event of the calculated threshold values Y being exceeded, the corresponding X coordinate is determined from the graph representing the course of the yarn profile of the averaged piecer ( FIG. 3 ). In this manner, a corresponding X-value is determined for each tau value.
[0063] In order to transfer these intermediate results into a comparable interrelationship, the yarn length s is firstly calculated as a function of the threshold values Y and the determined values of the X coordinate of the respective threshold value Y for the respective tau values. The yarn length s represents the spacing between the smallest yarn diameter and the x coordinates when exceeding the respective threshold value Y. The calculation takes place according to the following fiber band function:
[0000]
S
(
x
,
Y
)
=
X
(
tau
)
(
ln
(
1
-
(
Y
(
tau
)
thread
average
rotor
run
-
up
)
)
*
(
-
1
)
)
[0064] A yarn length average value s M is then formed from all the yarn lengths s(X, Y) calculated by means of the yarn band function. The yarn length average value s M is divided by the reduced drafting used in the measuring phase, producing a fiber band characteristic value s FBK (X, Y) for a value tau=1. For this, as shown in FIG. 4 , the fiber band characteristic values s FKB (X, Y) determined according to the fiber band function s(X, Y) are plotted over the number of piecing attempts. The fiber band characteristic value produced approximately from the tenth piecing attempt moves by a constant value so the fiber band characteristic can be assumed to be approximately constant.
[0065] The fiber band weight actual fiber band weight available can now be calculated for each feed path s feed of the fiber band 5 via the fiber band characteristic. The calculation takes place according to the formula:
[0000]
Actual
fiber
band
weight
=
1
,
000
roving
count
*
(
1
-
(
-
s
feed
fibre
band
characteristic
)
)
2
.
[0066] In order to ensure that during piecing at every draw-off instant the actually required fiber quantity is present in the spinning rotor 11 , the feed motor 3 , as already described, has to be in advance of that of the drive 26 of the draw-off mechanism 19 by the required comb-out time. Basically, the drive function of the feed motor 3 follows the drive function of the drive 26 . For this it is necessary to emulate the drive function of the drive 26 of the draw-off mechanism 19 for the drive function of the feed motor 3 . In this case, apart from the acceleration function, functional additions also have to be taken into account, such as, for example, the additional rotation, which leads to a reduction in the draw-off speed compared to the rotor speeds n rotor if, because of the lower rotor speeds during piecing, the situation arises that the spinning tension on the yarn 16 is less than normal, so the friction and therefore the false twist effect at the draw-off nozzle is not sufficient for a stable running state. The drive function of the feed motor 3 is determined by means of the fiber band function s(X, Y).
[0067] As the draw-off speed v draw-off of the yarn 16 and the acceleration of the draw-off are known at every instant and therefore also the draw-off path s draw-off , the feed speed is determined as a function of the draw-off path s draw-off and the time t part section required to spin a part section, of the fiber band 5 . The yarn feed path s feed is determined for each draw-off path s draw-off of the yarn 16 from the currently combed-out fiber band weight actual fiber band weight , which is calculated according to the aforementioned formula, and from the desired weight, which is produced from the reciprocal value of the yarn count. The yarn draw-off path s feed is determined according to:
[0000]
s
feed
=
actual
fibre
band
weight
desired
weight
=
actual
fiber
band
weight
*
yarn
count
.
[0068] The time t part section for spinning a part section is determined from the yarn draw-off path s draw-off and the instantaneous draw-off speed v draw-off , The time t part section for spinning a part section is calculated as follows:
[0000]
t
part
section
=
s
draw
-
off
v
draw
-
off
.
[0069] The instantaneous feed speed v feed of the fiber band 5 can be calculated from the time t part section calculated in this manner and the feed path s feed of the fiber band feed. Accordingly, the feed speed of the fiber band 5 can be calculated according to the formula:
[0000]
v
feed
=
s
feed
t
part
section
.
[0070] Thus the parameters required for automatic piecing can be determined from the automatically determined fiber band function or from the fiber band characteristic value automatically determined from the fiber band function, it being possible to use the fiber band characteristic value as a basis for the automatic determination of the piecing parameters independently of a change in spinning parameters or the spinning means, for example when using a rotor with a larger or a smaller diameter than that used to calculate the fiber band characteristic value.
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A method for piecing a yarn at a rotor spinning machine comprising plural spinning stations, wherein more than five piecers are successively produced in a measuring phase and coordinates of measurement values and associated measurement values from individual measurements of the piecers are evaluated for averaging and determining a fiber band function taking into account a drafting reduced for the measurement values, which reflects the fiber flow behaviour in the form of the respective fiber band quantity supplied to the rotor as a function of the transport path of the fiber band feed. The speed of the fiber band feed is controlled in a delayed manner from the run-up of the yarn draw-off, dependent on the rotor speed, by the fiber band function, such that the fiber shortfall quantity being produced from the fiber band function is compensated by dynamic feed addition with respect to height and length.
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BACKGROUND OF THE INVENTION
This invention relates generally to support mechanisms for stoppers used in casting measured quantities of molten steel and is particularly concerned with the provision of an improved mechanism enabling accurate location of the nose of the stopper relative to the well of the nozzle of the associated casting container.
It is established practice to control the feed of molten steel from a container to a mold by means of an elongate stopper located vertically within the container and having a lower nose end co-operating with a nozzle in the base of the container whereby axial movement of the stopper relative to the container opens and closes the nozzle in accordance with the desired rate of flow of the molten steel.
In one known arrangement, the upper end of the stopper is rigidly connected to one end of a transverse connecting arm by means of a cylindrical rod. More particularly the lower extent of the rod is housed within the upper extent of the stopper to extend axially of the stopper, a pin extending diametrically through the stopper and the cylindrical rod to secure the stopper to the rod, while the upper, threaded extent of the rod extends through a slot in the one end of the transverse rod and is secured to said rod by a series of washers, nuts and lock-nuts both above and below said rod.
The other end of the transverse connecting arm is mounted to the upper end of a vertical shaft located outside the container, said upper end of the shaft being threaded and projecting through a receiving hole in the other end of the connecting arm to which it is connected by means of a series of washers, nuts and lock-nuts.
Integrally formed in the lower regions of the vertical shaft is a rack with which co-operates a rotatable pinion in such a manner that rotation of the pinion results in axially upward or downward movement of the shaft and attached components.
Thus it will be appreciated that there has been described a substantially inverted U-shaped support mechanism for the stopper which can be moved bodily upwards and downwards relative to the container to adjust the axial position of the nose end of the stopper relative to the nozzle and by which the stopper can be pivoted about the central vertical axis of the shaft to provide arcuate adjustment in a horizontal plane of the position of the nose end of the stopper relative to the nozzle.
Such arrangements suffer from a number of disadvantages. Not the least of these is that, although the axial position of the nose end of the stopper can be accurately determined, the precise location of the stopper nose end in a horizontal plane cannot, because the stopper can only be swung about a fixed vertical axis. For controlled casting it is essential for the central longitudinal axis of the stopper to be co-axial with, and form a continuation of, the central axis of the nozzle. Existing arrangements cannot ensure such a situation.
Further, the provision of a diametrical pin and the drilling of the stopper to receive the pin to enable the stopper to be secured to the one end of the connecting arm is a distinct mechanical weak-spot in the support mechanism and is extremely prone to breakage--once this part of the stopper breaks, the stopper becomes unsupported.
The stopper includes a central bore through which an inert gas such as argon can be fed to the nose end thereof during casting. Said gas, which amongst other things attempts to reduce the build-up of alumina and cold steel at the nozzle, is fed to the bore in the stopper by means of a radial passage provided in one of the above-mentioned washers incorporated in the means connecting the cylindrical rod to the transverse arm and to which washer is connected a supply of said gas. The nature of said connection means is such that the path of the gas from the supply to the bore in the stopper is very prone to leakage whereby substantial volumes of gas can be lost to atmosphere.
Substantial build-up of undesirable deposits in the nozzle can occur in the known arrangement despite the presence of the argon gas, and clearance is usually achieved by raising the container to disengage the nozzle from the mould, inserting a lance up the nozzle and feeding oxygen to the well of the nozzle through said lance. However this can often cause irrepairable damage to the nozzle with the result that the cast has to be aborted.
If oxygen were to be fed to the nozzle by way of the central bore in the stopper,--i.e. the argon feed path--the intense heat created would be such as to melt the pin securing the stopper to the cylindrical rod, thus causing the stopper to break away from its support mechanism.
It would be desirable to be able to provide a stopper support mechanism less prone to the above disadvantages and in particular mechanically stronger and more maneuverable than the known arrangement.
SUMMARY OF THE INVENTION
According to the present invention there is provided a stopper support mechanism for casting containers, the mechanism comprising an elongate stopper for substantially upright location within the container with its nose end adjacent a nozzle in the base of the container, a substantially upright support shaft for location externally of the container and movable axially relative to the container, a transverse connecting arm extending between the upper end of the stopper and the upper end of the shaft, first means connecting the stopper to one end of said transverse arm and second means connecting the other end of said transverse arm to the shaft, the first connecting means comprising a two-piece clamp gripping the upper regions of the stopper, one piece of said clamp being secured to said one end of the transverse arm, and location means reacting between the clamp and the upper regions of the stopper to locate the stopper axially within the clamp, and the second connecting means comprising a block member secured to the upper end of the shaft and having formed therein a slot through which extends the other end of the transverse arm in such a manner as to permit fore and aft movement and sideways movement of the transverse arm in the block member prior to securing the transverse arm to the block member in a desired position relative to the shaft.
Conveniently the stopper includes a central, axial bore extending the full length thereof, a gas supply pipe being sealingly connected to the upper end of, to form a continuation of, the bore in the stopper.
In a preferred mechanism, one half of the clamp is welded to the one end of the transverse connecting arm.
The location means may comprise one or more radial apertures formed in the upper regions of the stopper and a co-operating projection formed on the inside face of the clamp and received within the aperture or one of the apertures in the stopper.
Preferably the other end extent of the transverse arm is threaded, said threaded extent being received within, to extend through, the slot in the block member, the arm being secured in position relative to the block member by opposed nuts on the threaded extent of the arm reacting against opposed faces of the block member.
Conveniently the threaded extent of the transverse arm is provided with a pair of opposed flats thereon, the height of the slot in the block member being substantially equal to the distance between the flats on the arm whereby said flats and slot co-operate to prevent relative rotation of the arm and block member about the central longitudinal axis of the arm.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a stopper support mechanism according to the invention;
FIGS. 2 and 3 are sections on the lines II--II and III--III of the mechanism of FIG. 1,
FIG. 4 is a plan view of the mechanism of FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to the drawings there is shown a casting container or tundish 2 of conventional form having an outlet 4 in the bottom wall thereof for the molten steel. The outlet 4 includes a well-portion 6 and a nozzle 8 for location in the associated mould.
Located in an upright position within the container 2 is a stopper indicated at 10 of generally cylindrical form and including a rounded nose end 12 shaped to seat in the well 6 of the outlet 4 to close said outlet. A central bore 14 extends axially of the stopper the full length of said stopper, said bore extending from the flat upper surface 16 of the stopper 10 to exit at said nose end 12 of the stopper. A series of axially spaced, radially extending apertures 18 are formed in the upper regions of the stopper 10 for reasons which will become apparent.
A main support shaft for the stopper 10, of generally conventional form, is indicated at 20, said shaft being mounted in a support 22 secured to the container 2. The shaft 20 incorporates a rack 24 with which co-operates a pinion 26 rotatable by means of a handle 28 to enable, on appropriate movement of the handle 28, raising or lowering of the shaft 20 relative to the container 2 in conventional manner.
The stopper 10 is mounted to the shaft 20 through a mechanism including a transverse connecting arm 30, a two-piece clamp 32 and a block 34. More particularly, the arm 30 includes a main extent 36 of cylindrical form to the free end of which is welded one half 38 of the clamp 32. The other half of the clamp 32 is shown at 40 and has a cylindrical pin 42 formed on its inside face, said pin being shaped to be received in any one of the apertures 18 in the stopper 10.
When securing the stopper 10 to the arm 30, the clamp 32 is positioned to embrace the upper regions of the stopper 10 with the pin 42 received within an associated one of the holes 18 in the stopper dependent upon the desired axial position of the stopper 10 in the container 2. Bolts are then tightened to secure the two pieces of the clamp 32 together whereby the stopper 10 is securely fixed to the arm 30.
The end of the arm 30 remote from the clamp piece 38 takes the form of a threaded extent 44 provided with a pair of opposed flats on the upper and lower surfaces of said extent 44. The block 34, which is of generally rectangular configuration, is welded to the upper end of the shaft 20 to be integral therewith and has a transversely elongate slot 46 formed therethrough extending fore and aft of the block considered in the longitudinal direction of the arm 30. FIG. 2 clearly shows the transverse extent of the slot 46, the height of which slot is substantially equal to the distance between the opposed flats on the extent 44 of the arm 30. Thus, the threaded extent 44 of the arm 30 can be passed through the slot 46 with the flats on the extent 44 co-operating with the upper and lower faces of the slot to prevent any relative rotation between the arm 30 and the block 34 about the central longitudinal axis of the arm.
The configuration of the slot 46 enables the arm 30 to be moved fore and aft of the block 34 and sideways in the block 34 before being secured relative to the block, whereby the location of the nose end 12 of the stopper 10 attached to the arm 30 can be accurately determined relative to the outlet 4. Once the desired position of the stopper is achieved, the arm is secured to the block 34 by means of washers, nuts and lock-nuts reacting between the arm 30 and the front and rear faces of the block 34, a sleeve 48, integral with one of the nuts, surrounding the threaded extent of the arm 30 to the side of the block 34 nearest the clamp 32 to prevent damage to said extent.
It will be appreciated that the stopper support mechanism described above is of extremely robust construction without any obvious weak points, unlike the known arrangements, and also permits very accurate positioning of the nose end 12 of the stopper 10 relative to the outlet 4. More particularly, the vertical position of the stopper 10 is determined by a combination of choice of location means 18,42 and by appropriate fine adjustment through the rack and pinion mechanism 24,26. The precise position of the nose end 12 in a horizontal plane can be achieved by appropriate fore and aft movement and sideways movement of the arm 30 in the slot 46 in the block 34, in combination with pivoting movement of the stopper 10, arm 30 and block 34 about the central axis of the shaft 20. Thus extremely accurate positioning of the stopper 10 such that its central axis is exactly aligned with the central axis of the outlet 4, which is essential for achieving satisfactory control of the flow of molten steel, can be achieved.
A gas supply pipe 50 is sealingly connected to the upper end of the bore 14 in the stopper 10. More particularly, the upper surface 16 of the stopper 10 is recessed to receive therein an annular washer welded or otherwise secured to the end of the pipe 50, said washer being retained in the top of the stopper by means of a refractory paste which effects a gas-tight seal between the pipe and the bore 14. Conveniently the pipe 50 includes a flexible extent to accomodate movement of the stopper 10.
During casting, and as is normal practice, inert argon is fed through the pipe 50 and bore 14 to the well 6 in an attempt, amongst other things, to minimise the build-up of alumina and cold steel. However such build-up does occur and can eventually cause blockage of the outlet 4.
In order to clear such a blockage, or to get rid of the undesirable deposits on the well 6, a supply of oxygen is attached to the pipe 50, the container 2 is raised so that the nozzle 8 is out of the associated mold, the stopper 10 is lowered so that its nose end 12 seats in the well 6 and oxygen is fed to the well via the bore 14. The oxygen reacts with the deposits to make them molten and so clear the outlet 4. Unlike the above-described known arrangement, there are no weak points in the arrangement of the invention, such as the diametrical pin connecting the stopper to the cylindrical rod, which can be affected by the heat build-up on said flushing with oxygen.
As well as locating the stopper 10 relative to the clamp 32, the provision of the pin 42--aperture 18 arrangement ensures that, should the pieces 38,40 of the clamp 32 inadvertently become loose, the stopper 10 does not immediately fall out of the clamp but is retained therein by co-operation between the pin 42 and associated aperture 18.
Thus there is provided a stopper support mechanism which is less prone to damage than known arrangements, which enables extremely accurate positioning of the stopper relative to the container outlet and which can prevent the build-up of alumina and cold steel between the nose end of the stopper and the well of the outlet. The consequential maintenance of a controlled gap between the stopper and the outlet enables more steel to be cast per container than heretofore. The stoppers have a longer working life, as has the container, saving on magnesite tiles and refractory materials. Less deskulling of the container is required and, together with the extra output through the same container, this results in less man-handling requirements.
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A stopper for a casting machine is comprised of a hollow rod of a refractory material which is supported at its outer periphery by a clamp carried by a transversely extending arm, the transversely extending arm having a threaded end that extends through an elongated slot in a block carried by a vertically moveable support shaft, the transverse arm being securable to the block in a desired position of adjustment of clamping nuts.
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BACKGROUND OF THE INVENTION
This invention relates to offshore drilling platform structures, and more particularly to secondary capping beams which are secured to, and extend outwardly from, the capping beams of a four pile platform to support modified self-contained drilling rigs of a size and weight normally installed on eight pile platforms.
BRIEF DESCRIPTION OF THE PRIOR ART
Traditionally tender-type platform rigs have been favored for developmental drilling in some offshore areas such as the Gulf of Mexico. In recent years the number of drilling tender-type rigs operating in this area has declined. Many companies have had to rely upon jack-up and self-contained platform rigs. Availability of deepwater, cantilever jack-up rigs is limited and, consequently, self-contained platform rigs are generally selected for use in water depths beyond 250 feet. When multiple wells and associated production equipment are contemplated, an eight pile platform is preferred to accommodate the size and weight of the rig, and to provide space for production equipment.
Secondary capping beams derive their name from being positioned atop the platform capping beams. The term "capping beam" refers to the primary structural member upon which the drilling rig skids.
The present secondary capping beam structure allows a rig designed for use with an eight pile platform to be adapted to a four pile platform configuration. Previously, a special class of self-contained platform rigs was designed and built to fit these minimum deck area platforms.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a support means for installing self-contained platform drilling rigs on four column satellite drilling platforms having restricted deck area.
Another object of this invention is to provide a support means whereby a full size rig may be installed on a small platform, thereby reducing installation and fabrication costs.
Another object of this invention is to provide a support means whereby the drilling rig may be located over half of the platform main deck to provide space for production quarters and equipment storage.
Other objects of the invention will become apparent from time to time throughout the specification and claims as hereinafter related.
The above-noted objects and other objects of the invention are accomplished by cantilever secondary capping beams which are secured to, and extending outwardly from, the capping beams of a four pile platform to support modified self-contained drilling rigs of a size and weight normally installed on eight pile platforms. Rig modifications comprise separation of pump and engine packages, a pipe rack extension, and a novel skidding system.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a top elevational view of an offshore drilling platform having secondary capping beams installed thereon;
FIG. 2 is a top elevational view of an offshore drilling platform deck showing secondary capping beams installed thereoon and portions of the deck structure removed;
FIG. 3 is a side elevational view of one of the secondary capping beams in accordance with the present invention;
FIG. 4 is a cross-sectional view of a portion of a secondary capping beam taken along the line 4--4 of FIG. 2;
FIG. 5 is a cross-sectional view of a portion of a secondary capping beam taken along the line 5--5 of FIG. 2;
FIG. 6 is a top elevational view of a cover plate of a secondary capping beam; and
FIG. 7 is a cross-sectional side elevation view taken along line 7--7 of the secondary capping beam of FIG. 2 showing the lifting means.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawings by numerals of reference, and particularly to FIGS. 1 and 2, there is shown a self-contained drilling rig 10 mounted on a four pile platform 11. The four platform columns or piles 12 are represented by dashed lines.
The cantilever secondary capping beams 13 are secured to the top of the platform capping beams 14. The pump package 15, together with the pipe rack deck 16, is supported over the water on one end of the secondary capping beams 13. The engine package 17 and main quarters package 18 are cantelivered on the other end of the beams 13. The substructure 19 is mounted on the skid base 20 between the packages. Center wing deck areas on the main deck of the platform between the pump package 15 and the engine package 17 provide space for locating combination tank and mud processing packages 21 and 22, respectively.
The combination tank package 21, which stores drilling and potable water and diesel fuel, is designed to span forty or forty-five feet distances. The arrangement of equipment permits the tank package 21 to mount directly on top of the platform capping beams 14, which are on forty foot centers. Live and dead static loads for the tank package 21 result in concentrated loads that are directly transferred into the main structural framing of the deck.
Movement of the skid base 20 over the well pattern 23 is such that all drilling loads and dead loads associated with the substructure 19 are contained within the forty by forty foot pattern of platform piles 12. Therefore, any major dynamic loads due to drilling are directly transmitted into the platform columns.
Referring now to FIGS. 2, 3, 4 and 5, the secondary capping beams 13 comprise paired elongated I-shaped girders preferably 124 feet long and 7 feet tall spaced apart on 5 foot centers. Each beam weighs approximately 110 tons. The 5 foot spacing provides torsional strength, and acts to increase the moment of inertia about the vertical axis because of lateral wind loads. The spacing also facilitates reaction load transfer through existing column and diagonal members of pump and engine package structural framing, and it simplifies fabrication by allowing welder access between the beams.
Each beam 13 is constructed of a top flange 24 and a bottom flange 25 formed from 2 inch thick by 30 inch wide steel plate and has a 1 inch thick longitudinal web portion 26. The web portions 26 are joined by a series of vertical, 1 inch thick longitudinally spaced transverse crossmembers 27 welded therebetween and extending between the flanges 24 and 26.
A series of 1 inch thick rectangular gusset plates 28 in axial alignment with the crossmembers 27 extend outwardly from the web portion 26 and extend vertically between the flanges 24 and 25. Vertical, 1 inch thick angular gusset plates or stiffeners 29 extend outwardly from the web portion 26 at the point where the beams 13 rest on the platform beam 14. The bottoms of the angular stiffener plates 29 extend beyond the bottom flange 25 to be welded to the top flange of the platform beam 14.
A series of 12 inch wide and 1 inch thick horizontal crossmembers 30 at the top and bottom of the transverse crossmembers 27 extend between the top and bottom flanges 24 and 25 and are welded to the crossmembers 27 and the flanges 24 and 25.
Cover plates 31 are welded to the outer surface of the top and bottom of the flanges 24 and 25 to increase bending strength of the beams 13 over the platform deck support points. The cover plates 31 are located on the beams 13 at the areas of maximum bending moment stress.
Walkways 32 are provided at each end of the inboard secondary capping beams 13 and extend longitudinally inward therefrom a distance of 30 feet. The walkways 32 comprise a structural steel frame 33 welded to the bottom flanges 25 and the web portion 26. A handrail 34 is welded to the frame 33 and extends vertically upward therefrom. A galvanized bar grating 35 welded to the frame 33 forms the floor of the walkway 32.
Since the top flanges 24 of the secondary capping beams become the new skidding surface, two of the outboard cover plates 31 as shown in FIG. 6 are provided with a series of longitudinally spaced apart jacking holes 36. Because the holes 36 are located in the area of greatest tensile stress on the beams, circular holes preferably 5 inches in diameter rather than conventional rectangular jacking holes are used to reduce stress concentration.
The secondary capping beams 13 are designed to be fabricated onshore where the welds may be ultrasonically inspected and transported to the platform site. Two opposing lift eyes 37 as shown in FIGS. 5 and 7 provide a means for hoisting the beams 13 into position by cranes.
The secondary capping beams in accordance with the present invention are designed to handle 1.5 million pounds cantilevered on both ends simultaneously with only a 40 foot span distance between the center support points. Beams cantilever 42 feet out over the water. Beams can also be placed on decks with 45 by 45 foot column row spacing, and with this spacing, cantilever distances are reduced along with associated stresses.
While this invention has been described fully and completely with special emphasis upon a preferred embodiment, it should be understood that within the scope of the appended claims the invention may be practiced otherwise than is specifically described herein.
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A pair of I-shaped elongated girders secured to, and extending outwardly from, the capping beams of a four pile platform, to form cantilever secondary capping beams which support modified self-contained drilling rigs of a size and weight normally installed on eight pile platforms. Rig modifications comprise separation of pump and engine packages, a pipe rack extension, and a novel skidding system.
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SUMMARY OF THE INVENTION
This invention relates to shelf support brackets of the type having one or more hooks which engage slots in an upright support member. The invention is particularly directed to a lock which prevents unintended removal of the bracket hooks from the slots.
Shelves of the type described are utilized to display carpet samples wherein customers are invited to remove carpet samples from the shelf for insection. In the case of some bulkier carpet samples, a customer will sometimes fail to properly remove the sample from the shelf. Instead the customer grasps a portion of the shelf and tries to lift it with the result that the shelf bracket hooks tend to disengage from the slots of the upright support member. Also, sometimes when a customer tries to remove a sample from one shelf he accidently bumps a higher shelf, tending to dislodge it from the upright.
Accordingly, the primary objects of the present invention are to prevent inadvertent dislodgement of a sample shelf and to accomplish this by a shelf support lock which prevents inadvertent displacement of the bracket hooks associated with the shelf.
Another object is to construct a lock of the type described which is readily installed.
Another object is a lock of the type described which can be installed on either side of a shelf support bracket.
Another object is to construct a lock of the type described so it may be engaged in the same slot as a hook on the shelf support bracket.
Another object is a lock complying with the foregoing objects which can be fabricated in a single piece.
Another object is a lock of the type described which does not require any spring-loaded parts or the like.
Other objects will appear from time to time in the following specification, drawings and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a shelf support lock according to the present invention, showing the lock in place on a shelf support bracket.
FIG. 2 is a side elevation view of a shelf support bracket and upright support member, with a shelf support lock according to the present invention in place.
FIG. 3 is a side elevation view of the shelf support lock.
FIG. 4 is a front elevation view of the shelf support lock.
DETAILED DESCRIPTION OF THE INVENTION
A shelf support lock 10 constructed in accordance with the present invention, and its manner of use, are shown in FIGS. 1 and 2. The lock 10 fits on a shelf support bracket 12 to prevent it from disengaging the upright support member 14. The upright support member 14 has a plurality of slots 16. The upright member 14 is attached to a wall or otherwise held in vertical position. The slots 16 have a width suitable for receiving hooks of the shelf support bracket 12. The double row of vertically-spaced slots 16 is typical.
The shelf support bracket 12 has an arm 18 which terminates at a body portion 20. A pair of hooks 22 (FIG. 2) extend from the body portion to engage a slot 16 in the upright support member 14. Each hook has a downwardly extending finger portion 24 which engages the bottom edge of a slot 16 to prevent the shelf bracket from falling out of the slot. While the arm 18 of the bracket 12 has been shown as extending downwardly at an angle, it will be understood that other arrangements are possible and the present invention can be used with such alternate configurations, including the usual horizontal shelf support bracket.
Looking at FIGS. 3 and 4, the parts of the lock 10, all of one-piece stamped metal are shown. The lock has a central member 26 which in the illustrated embodiment is an elongated member. At the upper end of the central member 26 is a first attachment clip 28. A second attachment clip 30 is formed at the bottom of the central member 26. Both the first and second attachment clips may advantageously be formed by bending the ends of the central member. An ear 32 is formed on the side of the central member 26. In a preferred embodiment a second ear 34 may be formed on the opposite side of the central member, giving the lock 10 a generally cruciform shape.
The use, operation and function of the invention are as follows:
The lock 10 is placed on the body portion 20 of the bracket 12 before the bracket is mounted on the upright support 14. The user slides the lock from the edge of the body portion having the hooks toward the arm 18 until the attachment clips 28 and 30 engage the body portion. When the ear 32 is clear of the hooks, the bracket 12 is inserted into the upright support with hooks 22 engaging slots 16. Then the user slides the lock toward the upright member 14 until the ear 32 projects into a slot 16. The ear 32 and the hook finger 24 prevent inadvertent removal of the shelf bracket.
With some bracket configurations it may be possible to use an alternate mounting procedure. In one such alternate procedure the shelf support bracket 12 is inserted into the upright support member 14 in the usual manner. Once this is done the bracket 12 will be in the position shown in FIGS. 1 and 2, with the fingers 24 of the hooks 22 engaging the bottom edge of slots 16. The lock 10 is then placed on the body portion 20 of the bracket 12 by first slipping the second attachment clip 30 on to the body portion 20 at a point near the junction of the body portion 20 and arm 18. Due to the angled shape of the arm the first attachment clip does not interfere with the top edge of the body portion while the second attachment clip is being engaged. The user then slides the lock toward the upright support member 14 so that the first attachment clip 28 engages the top of the body portion 20 of the bracket 12. At this point the first and second attachment clips will engage the body portion between the clip and the central member 26 of the lock. To fully engage the lock the user slides it toward the upright member 14 until the ear 32 of the lock projects into a slot 16 of the upright member 14. The location of the ear 32 along the central member 26 is such that the top edge of the ear is adjacent the top edge of the slot (see FIG. 2). In this position the ear prevents vertical motion of the bracket.
When the user wishes to remove the bracket, he simply removes the lock 10 by sliding it away from the upright member 14 and then lifting the bracket 12 up and out of the slots 16.
It will be understood that the above-described procedure may be somewhat different for other forms of shelf support brackets. But in any event the lock ends up with an ear projecting into a slot with the central member of the lock engaging the shelf support bracket.
One of the advantages of the present invention is that since it slidably engages the shelf support bracket and upright member there is no need for any springs or spring-loaded parts. No part of the lock undergoes tension, compression or bending in order to engage the lock. Since these types of actions tend to cause parts to fail, their absence in the present invention imparts inexpensive quality, greater durability and longer service life.
Another advantage of the present invention is the second ear gives the lock a symmetrical configuration which permits it to be attached to either side of a shelf support bracket. This is important because frequently the brackets will be installed in close quarters in which one side of the bracket may not be accessible. A good example is the double row of slots in the upright member 14 of FIG. 1. Once a first shelf support bracket is in place a second bracket placed adjacent to the first wall have only one side easily available for installing a lock. The lock of the present invention easily adapts to this situation.
A further advantage of the present lock is its simple design allows it to be formed from a one-piece stamping. Thus the lock can be economically manufactured with the same types of equipment used to manufacture the shelf support brackets themselves.
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A lock for a shaft bracket of the type having hooks which engage slots in an upright support member. The lock prevents inadvertent raising of the shelf support bracket hooks which could cause the hooks to fall out of the slots. The lock is of one-piece construction having clips which slidably engage the shelf support bracket. An ear on the lock projects into a slot of the upright support member, adjacent the top edge of the slot. The ear prevents vertical movement which could release the hook from the slot.
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BACKGROUND OF THE INVENTION
Ion implanters are commonly used in the production of semiconductor wafers. An ion source is used to create an ion beam, which is then directed toward the wafer. As the ions strike the wafer, they dope a particular region of the wafer. The configuration of doped regions defines their functionality, and through the use of conductive interconnects, these wafers can be transformed into complex circuits.
A block diagram of a representative ion implanter 100 is shown in FIG. 1 . Power supply 101 supplies the required energy to the ion source 102 to enable the generation of ions. An ion source 102 generates ions of a desired species. In some embodiments, these species are mono-atoms, which are best suited for high-energy implant applications. In other embodiments, these species are molecules, which are better suited for low-energy implant applications. The ion source 102 has an aperture through which ions can pass. These ions are attracted to and through the aperture by electrodes 104 . These exiting ions are formed into a beam 10 , which then passes through a mass analyzer 106 . The mass analyzer, having a resolving aperture, is used to remove unwanted components from the ion beam, resulting in an ion beam having the desired energy and mass characteristics passing through resolving aperture. Ions of the desired species then pass through a deceleration stage 108 , which may include one or more electrodes. The output of the deceleration stage is a diverging ion beam.
A corrector, or collimator, magnet 110 is adapted to deflect the divergent ion beam into a set of beamlets having substantially parallel trajectories. Preferably, the collimator magnet 110 comprises a magnet coil and magnetic pole pieces that are spaced apart to form a gap, through which the ion beamlets pass. The coil is energized so as to create a magnetic field within the gap, which deflects the ion beamlets in accordance with the strength and direction of the applied magnetic field. The magnetic field is adjusted by varying the current through the magnet coil. Alternatively, other structures, such as parallelizing lenses, can also be utilized to perform this function.
Following the angle corrector 110 , the ribbon beam is targeted toward the workpiece. In some embodiments, a second deceleration stage 112 may be added. The workpiece is attached to a workpiece support 114 . The workpiece support 114 provides a variety of degrees of movement for various implant applications.
The components between the ion source and the workpiece comprise the beamline. These components transform the ions generated by the ion source into a ribbon beam capable of implanting ions into a workpiece, such as a semiconductor wafer.
The workpiece support is used to both hold the wafer in position, and to orient the wafer so as to be properly implanted by the ion beam. To effectively hold the wafer in place, most workpiece supports typically use a circular surface on which the workpiece rests, known as a platen. Often, the platen uses electrostatic force to hold the workpiece in position. By creating a strong electrostatic force on the platen, also known as the electrostatic chuck, the workpiece or wafer can be held in place without any mechanical fastening devices. This minimizes contamination and also improves cycle time, since the wafer does not need to be unfastened after it has been implanted. These chucks typically use one of two types of force to hold the wafer in place: coulombic or Johnson-Rahbeck force.
The workpiece support typically is capable of moving the workpiece in one or more directions. For example, in ion implantation, the ion beam is typically a scanned or ribbon beam, having a width much greater than its height. Assume that the width of the beam is defined as the x axis, the height of the beam is defined as the y axis, and the path of travel of the beam is defined as the z axis. The width of the beam is typically wider than the workpiece, such that the workpiece does not have to be moved in the x direction. However, it is common to move the workpiece along the y axis to expose the entire workpiece to the beam.
The uniformity of the ion beam is critical to successful implantation. Low energy levels, such as those used for shallow implants, make it even more difficult to maintain ion beam uniformity. If the concentration of ions across the beam width is uneven, the implanted substrate will have non-uniform characteristics and parameters, which will affect its performance and usefulness.
SUMMARY OF THE INVENTION
The problems of the prior art are overcome by the ion implantation apparatus and method described in the present disclosure. The disclosure provides an apparatus and method for ion implantation that include destabilizing the ion beam as it passes through a magnetic field, preferably a dipole magnetic field. By introducing a bias voltage at certain points within that magnetic field, electrons from the plasma are drawn toward the electrodes, thereby causing the ion beam to expand due to space charge effects. The bias voltage can be introduced into the magnet in a region where the magnetic field has only one component. Alternatively, the bias voltage can be in a region wherein the magnetic field has two components.
BRIEF DESCRIPTION OF FIGURES
FIG. 1 represents a traditional ion implanter;
FIG. 2 represents a cross-section of the collimator magnet in FIG. 1 , taken in the x-y plane;
FIG. 3 represents a top view of a first embodiment of the electrodes shown in FIG. 2 , taken in the x-z plane;
FIG. 4 represents a top view of a second embodiment of the electrodes shown in FIG. 2 , taken in the x-z plane;
FIG. 5 represents a cross-section of a collimator magnet in the x-y plane and shows the effects of the electrodes as used in accordance with a first embodiment;
FIG. 6 represents a cross-section of a collimator magnet taken along the y-z plane and shows the magnetic field lines at the edge of the collimator magnet;
FIG. 7 represents a cross-section of a collimator magnet taken along the x-y plane and shows the effects of the electrodes as used in accordance with a second embodiment;
FIG. 8 represents a graph quantifiably showing the effects of the electodes as used in accordance with a second embodiment;
FIG. 9 represents a graph quantifiably showing the effects of a negative bias voltage when used with a boron ion beam;
FIG. 10 represents a cross-section of a collimator magnet taken along the x-y plane, showing the use of elements on both poles; and
FIG. 11 illustrated a representative ion density distribution for a low energy level ion beam.
DETAILED DESCRIPTION OF THE INVENTION
As described above, the ion beam passes through various components before reaching the workpiece. One challenge in this process is to insure that the ion beam remain uniform across its width. In some cases, the ions tend to congregate close to the center, with fewer on either side of the centerline, as shown in FIG. 11 . This results in an uneven ion implantation in the workpiece.
FIG. 2 shows a first embodiment. The vertical lines 210 represent the magnetic (B) field within the collimator magnet 200 , while the ⊙ represents the path of the ion beam, coming out of the page. In this embodiment, electrical conductors, or electrodes 220 , preferably in the shape of strips, are inserted in the dipole magnetic field of the collimator magnet 200 . In one embodiment, the electrodes 220 are affixed directly to the magnet 200 , so as to remain out of the beam path. The electrodes 220 can be affixed to either the north or south poles, or both poles, if desired. Alternatively, the electrodes can be held in place using other methods. The only requirement is that the electrodes be electrically isolated from their environment. Each electrode 220 is preferably in communication with an independent power supply 250 , which is used to supply a bias voltage to the electrode.
FIG. 3 shows one possible shape of the electrodes. These electrodes 200 can be printed circuit strips. In certain embodiments, these strips are 1 inch wide, 2 inches long and 0.125 inches thick, although other dimensions are within the scope of the disclosure. In the preferred embodiment, each electrode is in communication with an independent power supply (as shown in FIG. 2 ), such that the bias voltage applied to any electrode is independent of the bias voltage applied to any other electrode.
FIG. 4 shows a second embodiment. In this embodiment, rather than using elongated strips, electrically conductive elements, such as pins are used. These pins can be arranged as a single row of pins, as shown in FIG. 4 . As described above, each of these pins is preferably in communication with a separate power supply so as to enable the creation of bias voltages, independent of the other pins.
In both embodiments, the electrodes 220 are preferably insulated from the magnet. The bias voltages applied to the electrodes 220 can be static (i.e. DC voltage), or more preferably, a pulsed D.C. voltage. A pulse of positive voltage will cause the electrons in the ion beam to move toward the electrode. This causes the ion beam to become de-neutralized, or “blow up”, in that region, due to space charge effects. As the ion beam continues to pass through the magnet, it regains its shape, although its ion concentration has been reduced. The magnitude and duration of the bias voltage pulse determines the amount of expansion experienced by the ion beam. In other embodiments, a negative bias voltage can be used. For example, low energy boron ion beams can be enhanced by the use of negative bias voltages.
In certain embodiments, the electrodes 220 are well within the boundaries of the magnet, such as more than 2-3 inches, so that the magnetic field has a significant vertical component (B y ), with little or no B x or B z component. Therefore, the existing magnetic field and the electric field created by the application of the bias voltage are in the same direction. Thus, the electrons are somewhat restricted in their motion, as charged particles are reluctant to cross magnetic field lines. Therefore, the ion beam expansion described above remains very localized. In other words, the electrode only controls that portion of the ion beam that exists in the volume defined by the magnetic field lines and the element itself. FIG. 5 shows an example of this localized effect in creating a deneutralization region 230 . The deneutralization region appears as a rectangular column, defined by the electrode on one side and the height of the magnet on the other side.
Since this technique is primarily used to reduce the concentration of ions, it is used to reduce the intensity of the beam to its lowest level. In other words, this technique is not used to bring all portions of the ion beam to the average value. Rather, it is used to bring all portions of the ion beam to the lowest value.
In certain embodiments, as shown in FIGS. 2 and 5 , the electrodes 200 are only placed on one pole of the magnet. In alternate embodiments, electrodes 200 are placed on both the north and south poles.
In a second embodiment, the electrodes are placed near the edge of the collimator magnet, or outside the edge of the magnet, but within the magnetic field. In these locations, the magnetic field has a z component, due to the irregularly shaped magnetic field lines, as seen in FIG. 6 . In certain embodiments, the electrodes 220 are placed on the edge nearest the workpiece 175 , as the beam has greater parallelism at this location.
Since the magnetic field has a z component, the electrical field created by the electrodes crosses with this component of the magnetic field to create a force in the x direction. FIG. 7 shows the effects of a bias voltage in this embodiment. The application of a positive D.C. voltage to an electrode causes several effects. Electrons within the column defined by the electrode are accelerated toward the electrode. However, the electrons are pushed in the x direction due to the force created by the crossed E and B fields. Thus, the region defined by the electrode is stripped of electrons, creating a deneutralization region 230 , where ions are not space charged neutralized. The region adjacent to this region receives a surplus of electrons, creating a region of improved space charge neutralization 240 .
FIG. 7 shows each electrical element 220 having a dedicated power supply 250 . This power supply 250 is capable of providing positive or negative voltage, and is capable of supplying a constant voltage or can generate voltage pulses. In other embodiments, these pulses can be of varying durations. In certain embodiments, each element is not in communication with a dedicated power supply, rather two or more elements share a common supply.
The effect of energizing a single electrode 220 is best seen in FIG. 8 . Line 260 represents the percentage change in the ion beam moving along the X dimension (as compared to an average ion beam). Element 220 is located at its respective X position within the magnetic field. Electrode 220 is energized with a positive voltage. In the regions located remote from the electrode, no change in the ion beam is detected. However, in the column directly above the electrode, the ion beam is decreased by about 30%. This corresponds to region 230 in FIG. 7 . Because of the force created by the orthogonal magnetic and electrical fields, the region adjacent to the electrode 220 is increased by nearly 40%, which corresponds to region 240 in FIG. 7 .
Note that FIG. 8 shows the region adjacent to the element 220 on its left is enhanced. This is due to the placement of the electrode with respect to the magnet. For example, by placing the electrode on the opposite pole, the force created would be in the opposite direction, and therefore the region adjacent to the right would be enhanced. Similarly, if the electrodes were placed on the opposite end of the magnet, the force created would be reversed.
FIG. 9 shows the effect of a negative bias voltage on a boron ion beam. Note that the ion density is greatly enhanced in the column where the energized electrode is located.
While these figures show the effects of energizing a single electrode, it is anticipated that a plurality of electrodes will be energized. In this scenario, the effects of each individual electrode add to the effects of the other energized electrodes, according to the laws of superposition and create an overall effect across the entire ion beam.
As described above, it is within the scope of the disclosure to affix electrodes 220 on both poles. FIG. 10 shows one such embodiment. Note that in FIGS. 7 and 8 , the beam was enhanced to the left of the energized element 220 . This was due to the direction of the electrical and magnetic fields. By placing electrodes 220 on both poles, and selectively activating them, it is possible to create forces that push away from the centerline and toward the outside of the ion beam. Dashed line 300 represents the uneven ion density of the ion beam. Positive voltages are applied to two elements in this example, as denoted by the “+++++” symbols. The electron depleted column bound by the electrode(s) has a higher space potential due to space charge dominated by residual ions. As a result, an electric field appears across the sheath that separates the column from its boundary (the biased electrode). This electric field, in conjunction with the z component of the magnetic field, causes a drift of charged particles (plasma) in the direction of E×B. The directions of E and B reverse at opposite ends of the column, leading to drifts in the same direction. It is this plasma migration from one column to the adjacent one that causes an enhancement of beam transport in the adjacent region, thus an increase in propagated beam current. To reverse the direction of the drift, the z component of the B field has to be reversed. This can be done, for example, by locating a set of controlling electrodes in the other fringe (in the direction of propagation) of the dipole field.
While the above disclosure describes the use of electrodes within the collimator magnet, the disclosure is not limited to this embodiment. In another embodiment, the electrodes are placed within the mass analyzer magnet 106 . In another embodiment, an additional dipole magnetic field, separate from those traditionally present in FIG. 1 , is inserted into the beamline. One possible placement of such a magnet field is between the collimator magnet 110 and the second deceleration stage 112 . However, this additional magnetic field may be located anywhere in the beamline. In all cases, the dipole magnetic field is preferably created across the small dimension of the ribbon beam, as can be seen in FIG. 2 . In these embodiments, the effect of the electrodes is as described above.
Measuring devices, such as Faraday cups, can be used to measure the resulting ion beam at a plurality of locations along the X dimension. These measurements then provide the feedback necessary to tune the bias voltages at the various elements 220 . This feedback is preferably provided to control logic, which then determines which elements to energize, and the appropriate bias voltages and durations to be used. In this manner, the uniformity of the ion beam can be improved.
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An apparatus and method for ion implantation that include destabilizing the ion beam as it passes through magnetic field, preferably a dipole magnetic field is disclosed. By introducing a bias voltage at certain points within the magnetic field, electrons from the plasma are drawn toward the magnet, thereby causing the ion beam to expand due to space charge effects. The bias voltage can be introduced into the magnet in a region where the magnetic field has only one component. Alternatively, the bias voltage can be in a region wherein the magnetic field has two components.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a U.S.C. 371 national phase entry of PCT International Application No. PCT/US00/01160, filed 19 Jan. 2000 which claims priority benefit from U.S. Provisional Application No. 60/117,209, filed 25 Jan. 1999.
BACKGROUND OF THE INVENTION
This invention pertains to novel fibers made of α(1→3) polysaccharides, and a process for their production. The fibers of the invention have “cotton-like” properties but can be produced as continuous filaments on a year-round basis. The fibers are useful in textile applications.
Polysaccharides have been known since the dawn of civilization, primarily in the form of cellulose, a polymer formed from glucose by natural processes via β(1→4) glucoside linkages; see, for example, Applied Fibre Science , F. Happey, Ed., Chapter 8, E. Atkins, Academic Press, New York, 1979. Numerous other polysaccharide polymers are also disclosed therein.
Only cellulose among the many known polysaccharides has achieved commercial prominence as a fiber as a consequence of the many useful products derived therefrom. In particular, cotton, a highly pure form of naturally occurring cellulose, is well-known for its beneficial attributes in textile applications.
It is further known that cellulose exhibits sufficient chain extension and backbone rigidity in solution to form liquid crystalline solutions; see, for example O'Brien, U.S. Pat. No. 4,501,886. The teachings of the art suggest that sufficient polysaccharide chain extension could be achieved only in β(1→4) linked polysaccharides and that any significant deviation from that backbone geometry would lower the molecular aspect ratio below that required for the formation of an ordered phase.
More recently, glucan polymer characterized by α(1→3) glucoside linkages has been isolated by contacting an aqueous solution of sucrose with GtfJ glucosyltransferase isolated from Streptococcus salivarius , Simpson et al., Microbiology, vol 141, pp. 1451–1460 (1995). Highly crystalline, highly oriented, low molecular weight films of α(1→3)-D-glucan have been fabricated for the purposes of x-ray diffraction analysis, Ogawa et al., Fiber Diffraction Methods, 47, pp. 353–362 (1980). In Ogawa, the insoluble glucan polymer is acetylated, the acetylated glucan dissolved to form a 5% solution in chloroform and the solution cast into a film. The film is then subjected to stretching in glycerine at 150° C. which orients the film and stretches it to a length 6.5 times the original length of the solution cast film. After stretching, the film is deacetylated and crystallized by annealing in superheated water at 140° C. in a pressure vessel. It is well-known in the art that exposure of polysaccharides to such a hot aqueous environment results in chain cleavage and loss of molecular weight, with concomitant degradation of mechanical properties. Thus, considerable benefit would accrue to a process which would provide the high orientation and crystallinity desired for fibers without a reduction in molecular weight.
It is highly desirable to discover other polysaccharides having utility as films, fibers or resins because of their widespread importance in the global ecosystem. Polysaccharides based on glucose and glucose itself are particularly important because of their prominent role in photosynthesis and metabolic processes. Cellulose and starch, both based on molecular chains of polyanhydroglucose are the most abundant polymers on earth and are of great commercial importance. Such polymers offer materials that are environmentally benign throughout their entire life cycle and are constructed from renewable energy and raw materials sources.
The properties exhibited by cellulose and starch are determined by the nature of their enchainment pattern. Hence, starch or amylose consisting of α(1→4) linked glucose is not useful for fiber applications because it is swollen or dissolved by water. Alternatively, cellulose, having β(1→4) enchainment, is a good structural material being both crystalline and hydrophobic, and is commonly used for textile applications as cotton fiber. Like other natural fibers, cotton has evolved under constraints, wherein the polysaccharide structure and physical properties have not been optimized for textile uses. In particular, cotton fiber offers short fiber length, limited variation in cross section and fiber fineness and is produced in a highly labor and land intensive process.
Thus, it is desirable to form new structural polysaccharides through processes such as enzymatic synthesis or through genetic modification of microorganisms or plant hosts and fibers made from such new polysaccharides that retain the desirable features of biodegradability, renewable resource-based feedstocks and low cost.
SUMMARY OF THE INVENTION
The present invention concerns a polysaccharide fiber, comprising: a polymer comprising hexose units wherein at least 50% of the hexose units are linked via an α(1→3) glycoside linkage, said polymer having a number average degree of polymerization of at least 100.
The present invention also concerns a process for producing a polysaccharide fiber, comprising the steps of: dissolving a sufficient amount of a polymer comprising hexose units, wherein at least 50% of the hexose units are linked via an α(1→3) glycoside linkage, in a solvent or in a mixture comprising a solvent to form a liquid crystalline solution, and spinning a polysaccharide fiber from said liquid crystalline solution.
The present invention further concerns a liquid crystalline solution, comprising: a solvent and an amount sufficient to form liquid crystals of a polymer comprising hexose units wherein within the polymer at least 50% of the hexose units are linked via an α(1→3) glycoside linkage.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic diagram of an apparatus for air gap or wet spinning of liquid crystalline solutions of hexose polymer to form polysaccharide fibers.
DETAILED DESCRIPTION
In one of the surprising aspects of the present invention, it has now been found that a polymer comprising hexose units, wherein at least 50% of the hexose units within the polymer are linked via an α(1→3) glycoside linkage, can form a liquid crystalline solution when a sufficient amount of the polymer is dissolved in a solvent or in a mixture comprising a solvent, and that from this solution can be spun a continuous, high strength, cotton-like fiber highly suitable for use in textiles either in a derivatized form, a non-derivatized form or a regenerated form. By “regenerated” is meant that any derivative groups added during the preparation of the fiber are removed.
Suitable for use in the present invention are hexose polymers comprising repeating hexose monomer units wherein at least 50% of the hexose units are linked by an α(1→3) glycoside linkage. Such hexose polymers include those formed from the monomers glucose, fructose, mannose, galactose, combinations thereof, and mixtures of any of the foregoing. A linkage involving a glucose monomeric unit can be called a glucoside linkage. Polyhexose polymers used herein include both the dextrorotatory (D) and levorotatory (L) enantiomers of such polymers as well as racemic mixtures thereof. Preferred are the D-forms; most preferred is D-glucose. A racemic mixture is less preferred.
By “α(1→3) glycoside linkage” is meant that within the polymer, the repeating monomeric units are linked in a particular manner dictated by an enchainment pattern. The nature of the enchainment pattern depends, in part, on how the ring closes when an aldohexose ring closes to form a hemiacetal. The open chain form of glucose (an aldohexose) has four asymmetric centers (see below). Hence there are 2 4 or 16 possible open chain forms of which D and L glucose are two. When the ring closes, there is a new asymmetric center created at C1 thus making 5 asymmetric carbons. Depending on how the ring closes, for glucose, α(1→4)-linked polymer, e.g. starch or β(1→4)-linked polymer, e.g. cellulose can be formed upon further condensation to polymer. The configuration at C1 in the polymer determines whether it is an alpha or beta linked polymer, and the numbers in parenthesis following alpha or beta refer to the carbon atoms through which enchainment takes place.
The polymer used to form the polysaccharide fiber of the present invention possesses a number average degree of polymerization of at least 100 and can range up to about 5,000. Preferably, the number average degree of polymerization ranges from about 200 to about 1,000.
The polysaccharides of the present invention can be homoglycans or heteroglycans. If only one type of hexose unit is used during preparation of the polysaccharide, a homoglycan is formed. Glucan is a homoglycan formed from glucose. If more than one type of hexose unit is used, a heteroglycan is formed.
The polymer of the polysaccharide fibers of the present invention can further comprise monomer units other than hexose units, such as pentoses. It is preferred that substantially all of the monomer units within the polymer in the present invention are hexose monomer units. By “substantially all” is meant at least 90%.
In a similar vein, the polysaccharide fibers of the present invention can further comprise monomer units linked by a glycoside linkage other than α(1→3), such as α(1→4), α(1→6), β(1→2), β(1→3), β(1→4) or β(1→6) or any combination thereof. At least 50% of the glycoside linkages in the polymer are an α(1→3) glycoside linkage. Preferably, substantially all of the linkages are α(1→3) glycoside linkages, and most preferably all of the hexose units in the polymer are linked by an α(1→3) glycoside linkage. By “substantially all” is meant at least 90%.
The polysaccharide fibers of the present invention are produced by dissolving the polymer, described above, in a solvent or in a mixture comprising a solvent, to form a liquid crystalline solution. Oriented fiber is then spun from the liquid crystalline solution.
The isolation and purification of various polysaccharides is described in, for example, The Polysaccharides , G. O. Aspinall, Vol. 1, Chap. 2, Academic Press, New York, 1983. In a preferred embodiment of the present invention, poly(α(1→3)-D-glucose) is formed by contacting an aqueous solution of sucrose with GtfJ glucosyltransferase isolated from Streptococcus salivarius according to the methods taught in the art. Any method which results in a purity of ca. 90% or greater is satisfactory. One such method is provided in detail hereinbelow.
The polymer comprising hexose units can be derivatized, preferably acetylated, most preferably close to 100% acetylated, in order to facilitate rendering the polysaccharide soluble in the spinning solvent to achieve a solids level sufficient for liquid crystals to form. For examples of representative polysaccharide derivatives useful herein, see The Polysaccharides , G. O. Aspinall, Vol. 2, Chap. 2, Academic Press, New York, 1983. Preferred derivatives include methyl, ethyl, hydroxyethyl, nitrate, acetate, proprionate and butyrate. A preferred derivatized polymer is a poly(α(1→3)-D-glucose acetate). Acetylation can be accomplished using the method described by O'Brien, op.cit., for acetylating cellulose. It can be useful to pre-activate the hexose polymer by first contacting it with acetic acid prior to its contact with an acetylation mixture such as a mixture of glacial acetic acid, acetic anhydride, and methylene chloride. Contact with the mixture is followed by the addition of perchloric acid to initiate esterification.
Following optional formation of the derivative, the polymer is dissolved in a solvent or in a mixture comprising a solvent to form a liquid crystalline solution. By “liquid crystalline solution” is meant a solution in which a spontaneous phase separation from randomly dispersed polymer molecules to domains of locally ordered molecules has occurred. Formation of the liquid crystalline solution is dependent on the solids content of the polymer so dissolved. “Solids content” refers to the amount of dry polymer before it is dissolved. It is calculated as the (wt. of polymer)/(wt. of polymer+wt. of solvent). A liquid crystalline solution must be formed in order to obtain an oriented fiber when the solution is spun. The amount of polymer needed to provide a solids content sufficient for liquid crystals to form depends on the polymer morphology and the polymer molecular weight. The onset of liquid crystallinity can be determined by an observable increase in the birefringence of the solution being formed. Birefringence can be determined by any convenient means as are known in the art.
Non-derivatized polymers and the derivatized polymers formed as described above are soluble in solvents including organic halides, organic acids, fluorinated alcohols, or mixtures thereof. Representative of such solvents are methylene chloride (dichloromethane), trifluoroacetic acid, trichloroacetic acid, dichloroacetic acid, formic acid, hexafluoroisopropanol, and mixtures such as trifluoroacetic acid/methylene chloride, trichloroacetic acid/methylene chloride, dichloroacetic acid/methylene chloride, and formic acid/methylene chloride. Other suitable solvents include molecules which are nonsolvents by themselves (e.g., water) in combination with strong organic acids, such as trifluoroacetic acid/water, trichloroacetic acid/water, dichloroacetic acid/water, or formic acid/water. Preferably, an acetylated polymer is dissolved in a mixture of trifluoroacetic acid and methylene chloride, most preferably as a 60/40 v/v. mixture of trifluoroacetic acid and methylene chloride, respectively, at a temperature between about 0 and about 25° C. while mixing, preferably mixing under high shear.
The particular benefits of the present invention are achieved by virtue of the formation of the liquid crystalline solution comprising a solvent and an amount sufficient to form liquid crystals of a polymer comprising hexose units wherein at least 50% of the hexose units are linked via an α(1→3)glycoside linkage from which a highly oriented, highly crystalline continuous filament can be drawn. A preferred liquid crystalline solution is one wherein substantially all of the hexose units are linked via an α(1→3)glycoside linkage. A preferred polymer for a liquid crystalline solution is poly(α(1→3)-D-glucose acetate). One of skill in the art will understand that the minimum polymer concentration (solids content) required for achieving the formation of the liquid crystalline phase will vary according to the specific molecular morphology and the molecular weight of the polymer. A liquid crystalline solution having a solids content of at least 10% is preferred. A solids content ranging from about 10% to about 35% is more preferred herein, and most preferred is about 20 to about 35%. In a preferred embodiment of the present invention, it has been found that the minimum polymer concentration for phase separation of 100% poly(α(1→3)-D-glucose) is ca. 15% by weight in a 60/40 mixture of trifluoroacetic acid and methylene chloride when the number average molecular weight of the polymer is ca. 60,000 Daltons. Optimum spinning performance for this particular polymer is achieved at about 20 to about 30% by weight solids content, which is most preferred.
Spinning from the liquid crystalline solution can be accomplished by means known in the art, and as described in O'Brien, op.cit. The viscous spinning solution can be forced by means such as the push of a piston or the action of a pump through a single or multi-holed spinneret or other form of die. The spinneret can be of any cross-sectional shape, including round, flat, multi-lobal, and the like, as are known in the art. The extruded strand can then be passed by ordinary means into a coagulation bath wherein is contained a liquid which dissolves the solvent of the spinning solvent but not the polymer thereof, thus causing the highly oriented polymer to coagulate into a fiber according to the present invention.
Under some circumstances, a superior result is achieved when the extruded strand first passes through an inert, noncoagulating layer, usually an air gap, prior to introduction into the coagulation bath. When the inert layer is an air gap, the spinning process is known as air-gap spinning. Under other circumstances, extrusion directly into the coagulation bath is preferred, known as wet-spinning. Preferred solvents for the coagulation bath include aliphatic alcohols, particularly methanol, ethanol, or isopropanol.
FIG. 1 is a schematic diagram of an apparatus for wet or air-gap spinning of polysaccharide fibers. Syringe pump 1 drives ram 2 at a controlled rate onto piston 3 of spinning cell 4 . A suitable syringe pump is a Harvard model 44. Spinning cell 4 can contain a metal filter, such as a Dynalloy® X5, 10 μm sintered metal filter, above spinneret 6 . Extrudate 12 is optionally directed through an inert non-coagulating layer and into liquid coagulating bath 8 and directed back and forth between guides 7 which, for example, can be ceramic or comprise Teflon® fluoropolymer. On exiting the coagulation bath, the extrudate can be optionally directed through a drawing zone between two independently driven rolls 9 and collected on bobbins, preferably stainless steel, at wind-up 11 .
If in a derivatized form, the polysaccharide fibers of the present invention can be retained in such derivatized form. However, it is preferred to regenerate such fibers by converting them back to the hydroxyl reconstituted form. This can be accomplished by numerous means known in the art, such as by contacting the polysaccharide fiber with an excess of a saponification or hydrolysis medium. One deacetylation means found to be satisfactory herein is base-catalyzed saponification. For example, the acetylated fiber can be contacted with 0.05 molar methanolic sodium methoxide, or with a dilute aqueous base solution, such as 5% aqueous sodium or potassium hydroxide, for 24–72 hours at room temperature, to remove ester groups, such as the acetyl group.
It is quite surprising that poly(α(1→3)-D-glucose) forms liquid crystalline solutions, and that the highly desirable fibers of the present invention can be spun therefrom. Likewise for other polyhexoses comprising at least 50% α(1→3) glycoside linkages in combination with other non preferred linkages, liquid crystalline behavior can be observed. For example, Nigeran which includes α(1→3) and α(1→4) glycoside linkages can be dissolved in a solvent to form a liquid crystalline solution. However, other α-linked polyglucoses, especially those containing substantially all α(1→6) or α(1→4) linkages, and more generally other α-linked polysaccharides do not exhibit similar behavior, for example amylose (starch) which has α(1→4) linkages, dextran with α(1→6) linkages, and pullulan with α(1→4) and α(1→6) linkages.
The white, lustrous fibers of the present invention are characterized by a tensile strength of at least 1 gram per denier, preferably 2 grams per denier.
EXAMPLES
Polymer Isolation
In the examples following, except Example 7, two batches of poly(α(1→3)-D-glucose) were employed, designated P1 and P2.
P1 was produced according to the following sequence. The mature peptide encoded by the gtf-J gene of Streptococcus salivarius (strain ATCC 25975) was cloned by PCR amplification of template DNA from Streptococcus salivarius using primers based on the gene sequence described in Genbank accession number Z11873 and by Giggard et al., J. Gen. Microbiol. 137 (Pt 11), 2577–2593 (1991).
PCR reactions were run using the 5′ primer SEQ ID NO:1:
5′-GGGAATTCCATATGAACATTGATGGTAAATATTAC
where SEQ ID NO:2, the sequence:
AACATTGATGGTAAATATTAC
corresponds to bases 555 through 547 of Genbank accession number Z11873 and the remaining 5′ bases provide an Nde I recognition site and a few 5′ bases to allow digestion of the PCR product with Nde I.
The 3′ primer SEQ ID NO:3 had the sequence (read 5′ to 3′)
5′-AGATCTAGTCTTAGTTTAGCACTCTAGGTGG
where SEQ ID NO:4 the sequence:
TTAGTTTAGCACTCTAGGTGG
corresponds to the reverse compliment of bases 4559 through 4580 in Genbank accession number Z11873 and the remaining bases provide an Xba I site and extra bases to allow digestion of the PCR product with Xba I.
The PCR product was digested with Nde I and Xba I then purified by agarose gel electrophoresis and isolated. The fragment was ligated into the E. coli protein expression vector pET24a (Novagen) that had been digested with Nde I and Nhe I. The ligation reaction was used to transform E. coli cell line DH10B, and six clonal colonies from that transformation were grown and plasmid DNA was isolated. The plasmid DNA from each of these lines was used to transform E. coli cell line DE3.
Single colonies from each transformation were grown overnight in rich media, the resultant culture was diluted to about 0.05 optical density units at 600 nm and then re-grown to 2 optical density units at 600 nm then protein expression from the pET24a plasmid was induced by the addition of 1 mM isopropylthiogalactoside. Cells were harvested by centrifugation after 3 hr, re-suspended in 50 mM KPO 4 buffer at pH 6 which also contained 0.2 mM phenylmethylsulfonyl fluoride and disrupted by sonication.
Clonal cultures producing active dextran sucrase were identified by adding 10 ml of the cell extract to 50 mM sucrose and 0.5 mg ml-1 T-10 dextran (Sigma) in a total reaction volume of 100 ml of 50 mM KPO 4 buffer. Active clones producing enzyme polymerize glucose using sucrose as the glucosyl donor and producing insoluble polymer thus clouding the reaction solution within about 10 minutes. The polymer was lyophilized to form a dry powder.
P2 was produced in a larger scale modification of the process for producing P1. Production of the crude enzyme was done by scaling the procedure employed for the production of P1 to two one-liter cultures in shake flasks. Isolated cells were disrupted by French Press disruption using the buffer system described above. The cell extract was diluted to 10 mg of protein ml-1, brought to 30% saturation with ammonium sulfate and centrifuged to remove a small amount of precipitate. The supernatant was brought to 70% saturation in ammonium sulfate and the precipitated protein isolated by centrifugation. The protein pellet was stored as a suspension in 70% saturated ammonium sulfate and used as the suspension.
Poly (α(1→3)-D-glucose) was produced by adding the ammonium sulfate suspension to a 2 1 solution of 200 mM sucrose in 50 mM KPO 4 buffer pH 6 and stirring overnight at 28° C. The insoluble glucose polymer produced was removed from solution by centrifugation, re-suspended in water (500 ml) and again centrifuged. The water wash was repeated two more times and the centrifuge pellet was concentrated by vacuum filtration on a sintered glass filter. The filter cake was stored at 4° C. prior to use.
Testing Methods
Physical properties such as tenacity, elongation and initial modulus were measured using methods and instruments conforming to ASTM Standard D 2101-82, except that the test specimen length was one inch. Reported results are averages for 3 to 5 individual filament tests.
Example 1
2.86 g of wet polymer P2 was boiled in 150 ml deionized water for 1 h. After cooling, the product was collected by filtration and washed 3× with glacial acetic acid. The polymer, still wet with acetic acid, was suspended in a prechilled (−25° C.) acetylating mixture consisting of acetic anhydride (20 ml), glacial acetic acid (14 ml) and methylene chloride (20 ml). Mechanical stirring was started and 70% aqueous perchloric acid (0.2 ml) was added to initiate esterification. The reaction mixture was allowed to warm to 0° C. and held there for 3 h. The reaction mixture was subsequently allowed to warm to room temperature and held for 1 h, then frozen in dry ice overnight, and then warmed to room temperature again.
The viscous, homogeneous solution of thus acetylated P2 polymer was precipitated in methanol with rapid stirring and collected by filtration. The filtrate was thoroughly washed twice with methanol, then five times with deionized water, and then four times with methanol. The washed product was collected by filtration and allowed to air dry yielding 1.78 g of purified acetylated polymer which was soluble in methylene chloride. Size exclusion chromatography in hexafluoroisopropanol containing 0.1 M sodium triflate was conducted through two Showdex 80M columns yielding relative molecular weight values of M n =60,800 and M w =202,300.
1.5 g of the thus prepared α(1→3) glucan acetate was combined with 2.79 g of a solvent mixture consisting of 100 parts by weight trifluoroacetic acid (99%) and 8 parts by weight deionized water to form a 35% solids solution. In order to dissolve the polymer therein, the mixture of polymer and solvent was first stirred by hand using a stainless steel spatula in order to homogenize the mixture. The homogenized mixture was then pumped back and forth between two syringes connected by a short length of 3 mm ID stainless steel tubing. Dissolution of the polymer in the solvent mixture was complete within 4 h at room temperature. The solution was examined microscopically through crossed polarizers and found to be highly birefringent, confirming an oriented, lyotropic liquid crystalline phase.
The liquid crystalline solution so formed was transferred into a vertically positioned polyethylene syringe fitted with a Dynalloy® X5 sintered stainless steel filter available from Fluid Dynamics/Memtec Group, Deland, Fla. Trapped air was allowed to migrate to the top of syringe and vented during installation of the syringe plunger. This assembly was then fitted to a vertically mounted Harvard model 55-1144 syringe pump for controlled rate extrusion according to the parameters given in Table 1. The syringe was fitted with a stainless steel single hole spinneret having a hole diameter of 0.005 inches and capillary length of 0.010 inches. The face of the spinneret was maintained 0.5 inches above the surface of the methanol coagulation bath. The filament was extruded at 20 ft/min, drawn into the bath and directed around ceramic guides at both ends of the coagulation tray to obtain a total travel in the bath of 14 feet. (See FIG. 1 ) The coagulated fiber, still wet with methanol, was wound onto stainless steel bobbins at 58 ft/min. The bobbins were soaked in methanol overnight and the filaments were allowed to air dry before mechanical testing. As spun filament tenacity/elongation/modulus values were 4.2/17.5/53.9 grams per denier/percent/grams per denier, respectively.
Example 2
The as-spun fiber of Example 1 was deacetylated to yield regenerated poly (α(1→3)-D-glucose) fibers with good mechanical properties. A small skein of the fiber of Example 1 was immersed in a large excess of 0.05M methanolic sodium methoxide and allowed to stand at room temperature for 24–72 h under nitrogen. The skein was removed, washed with methanol, blotted and air dried. Filament tenacity/elongation/modulus values were 2.7/12.5/51.3 grams per denier/percent/grams per denier, respectively.
Example 3
1.0 g of dried powder of P1 polymer was suspended in deionized water and boiled under nitrogen for 2 h. After cooling, the powder was collected by filtration and pressed to yield a wet filter cake. This was subsequently immersed in 100 ml of glacial acetic acid, stirred for 5 minutes at room temperature and collected by filtration. The acetic acid rinse was repeated and the powder was collected and pressed to remove excess acetic acid.
The filter cake was then added to a chilled (−25° C.) acetylation medium consisting of acetic anhydride (10 ml, 99.7%), glacial acetic acid (7 ml) and dichloromethane (10 ml). Perchloric acid (0.1 ml, 70%) was added and the reaction maintained with stirring at a temperature in the range of −30° C. to −2° C. for 6 h and then allowed to warm to 24° C. and held for 30 min. The resulting viscous mixture was precipitated into rapidly stirred methanol and then filtered. The filter cake was then washed once with methanol, followed by two washings with deionized water and then once with acetone. After drying, the yield was 1.2 g of purified acetylated polymer in the form of an off-white flake.
1 g of the thus prepared acetylated polymer was suspended in 3 g of a 60%/40% by volume mixture of trifluoroacetic acid (99%) and dichloromethane. After the polymer was dispersed in the solvent, the solution was mixed as described in Example 1. The resulting solution was lyotropic and highly fiber forming. The thus formed liquid crystalline solution was transferred to a polyethylene syringe fitted with a filter and extruded using the same general procedure as for Example 1. The filament was extruded at 10.4 fpm through a 0.5 inch air gap into methanol (bath length=13 ft) and wound up at 36 ft/min. As-spun filament tenacity/elongation/modulus values were 1.6/11.7/34.5 grams per denier/percent/grams per denier, respectively.
Example 4
A 6″ skein of the as-spun filament of Example 3 was prepared from 5 wraps of continuous filament and the ends were tied together. A 50 g weight was suspended from the bottom of the skein (consisting of 10 total filaments) and the assembly was immersed in a large excess of 0.05 m methanolic sodium methoxide and maintained under nitrogen for 96 h. The filament was removed, washed by immersion in fresh methanol and allowed to air dry. The thus regenerated or deacetylated filament tenacity/elongation/modulus values were 2.4/13.0/52.2 grams per denier/percent/grams per denier, respectively.
Example 5
Poly (α(1→3)-D-glucose) acetate fibers were prepared as described in Example 3, except that the wind-up speed was 23 ft/min and the coagulation bath temperature was 3° C. As-spun filament tenacity/elongation/modulus values were 1.9/14.2/32.7 grams per denier/percent/grams per denier, respectively.
Example 6
Polymer P1 (2.0 g) was added as a dried powder to a chilled (0° C.) mixture of glacial acetal acid (99%, 14 ml), acetic anhydride (99.7%, 10 ml) and dichloromethane (20 ml). The reactants were kept under nitrogen and a catalyst solution at 0° C. of perchloric acid (70% aqueous, 0.2 ml) in acetic anhydride (10 ml) was added dropwise with rapid stirring. After addition of the catalyst solution, the reactants were allowed to warm to room temperature and stirred for 5 h. The amber-colored viscous solution thus formed was precipitated into methanol. The filter cake was washed twice with methanol, collected by filtration and vacuum dried at 50° C. to yield 2.65 (g) of off-white polymer flake.
1.0 g of the thus acetylated polymer was dissolved in trifluoroacetic acid/dichloromethane (60/40 v/v, 4.0 g) and mixed using the method of Example 1. The resulting solution was lyotropic and fiber forming. Extrusion was carried out using the general procedures described in Example 1, and the specific conditions in Table 1 below, except that it was wet-spun. As-spun filament tenacity/elongation/modulus values were 0.94/14.4/23.1 grams per denier/percent/grams per denier, respectively.
Example 7
Nigeran (an alternating α(1→3), α(1→4) glucan), 0.86 g (from Asperigillus japonicus , Cat #N2888, Sigma-Aldrich Co.) was suspended in 50 ml of glacial acetic acid for 20 min and collected by filtration. This step was repeated once more and the starting material (still wet with acetic acid) was added to a three necked flask containing the acetylation medium prechilled to 2° C. and fitted with a thermocouple, stirrer and nitrogen inlet tube. The acetylation medium consisted of acetic anhydride (20 ml), glacial acetic acid (14 ml) and methylene chloride (20 ml). Perchloric acid, (0.2 ml, 70% aqueous) was then added dropwise with rapid stirring while maintaining the temperature between 2–5° C. The reaction was maintained at this temperature for 3 h and subsequently allowed to warm to room temperature for an additional 3 h. The acetylated polymer was then isolated by precipitation into methanol, and collected by filtration. Additional washings with methanol (2 times) were conducted yielding 0.96 g of a white product.
A 30% solids solution of the above polymer in trifluoroacetic acid/water (100/8 w/w) was prepared and observed to be birefringent when viewed through crossed polarizing filters verifying the existence of a liquid crystalline solution.
Comparative Example 1
0.5 g of the purified acetylated polymer of Example 6 was dissolved in trifluoroacetic acid/dichloromethane (60/40 v/v, 2.8 g) using the method of Example 1. The resulting solution was not lyotropic (a liquid crystalline solution did not form) because the solids content was below the critical concentration for liquid crystalline phase separation, and was poorly fiber forming. Filament extrusion was carried out as described for Example 4 and the specific conditions in Table 1. As-spun fibers were soaked in methanol for 24 h before being dried and tested. As-spun filament tenacity/elongation/modulus values were 0.54/17.2/17.4 grams per denier/percent/grams per denier, respectively.
Comparative Example 2
A skein of the as-spun filament of Comparative Example 1 was deacetylated in 0.05 m methanolic sodium methoxide using the procedure described in Example 2. Filament tenacity/elongation/modulus values were 0.4/2.5/25.1 grams per denier/percent/grams per denier, respectively. Thus, regeneration of the poorly oriented isotropically spun precursor fiber gave a poor fiber.
Comparative Example 3
Preparation of Debranched Amylose
α(1→6) branch points were enzymatically removed from common corn starch as follows. 300 g of corn starch was gelatinized by heating in 8 L of water at 100° C. for 1 hour. The gelatinized starch was cooled to 50° C. and 50 ml of 1 M acetic acid was added to adjust the pH to about 4. 1 million units of isoamylase (Sigma) were added in 25 ml of sodium acetate buffer (50 mM, pH 4.5) and the mixture was incubated at 45° C. for 4 hours.
1.2 L of butanol was added to the above reaction mixture, and the mix was boiled for 1 hour. The mixture was then allowed to cool to room temperature slowly overnight. The mixture was further cooled to 5° C. and the precipitate was collected by centrifugation (GS-3 Rotor, 9500 rpm, 30 minutes). The collected precipitate was resuspended in 8 L water, boiled for 30 minutes and precipitated a second time as above. After centrifugation the precipitate was washed with ethanol and dried overnight at 50° C. Gel Permeation Chromatography (GPC) was used to compare the resulting product with debranched starch before precipitation verifying removal of the short amylopectin branches.
Preparation of poly(α(1→4)-D-glucose)acetate (Polymer D)
Enzymatically debranched amylose from cornstarch (5.0 g), α(1→4)-D-glucose, was suspended in 100 ml water and boiled for 1 h under nitrogen. On cooling, the suspension was cooled to 0° C. and the swollen starch granules were collected by filtration. The wet filter cake was washed 4× with glacial acetic on the filter and the acid-exchanged filter cake was pressed to remove excess acetic acid. This was added to a reaction flask equipped with a paddle stirrer and charged with acetic anhydride (99.7%, 200 ml), acetic acid (99%, 70 ml) and dichloromethane (100 ml), all prechilled to 2° C. Perchloric acid (70% aqueous, 0.5 ml) was added dropwise while maintaining an ice bath around the reaction vessel. After 2 h the reaction mixture was clear and was precipitated by pouring into rapidly stirred methanol. The white product was washed twice in methanol and dried in vacuum at 50° C. The yield was 6.5 g of poly (α(1→4)-D-glucose acetate) which was readily soluble in dichloromethane and mixtures of trifluoroacetic acid with dichloromethane or water.
A 1.0 g portion of the thus acetylated polymer was dissolved in dichloromethane (4.0 g). The viscous solution was not liquid crystalline as evidenced by the absence of birefringence when viewed through crossed polarizers. The fiber forming solution was extruded using the general procedures for Example 1 and the specific parameters in Table 1. The extrudate was not sufficiently strong to allow for several passages through the coagulation bath and best spinning continuity was observed without the use of an air gap. As-spun filament tenacity/elongation/modules values were 0.5/70.6/13.9 grams per denier/percent/grams per denier, respectively.
Comparative Example 4
1.5 g of the acetylated poly (α(1→4)-D-glucose) of Comparative Example 3 was dissolved in a mixture of trifluoroacetic acid and water (4.5 g) 100/8 w/w to provide a 25% solids solution. The resulting spin dope was not liquid crystalline as evidenced by the absence of birefringence when viewed through crossed polarizers. The solution was transferred to a 5 ml syringe fitted with a scintered metal filter and extruded through 0.25 inch air gap using the general procedures of Example 1 and the specific parameters in Table 1. As in Comparative Example 2, the spinning threadline was not sufficiently strong to allow multiple passes in the coagulation bath. The as-spun fiber exhibited a dull appearance and measured filament tenacity/elongation/modulus values were 0.3/14.7/12.6 grams per denier/percent/grams per denier, respectively.
TABLE 1
Polymer
Dia
Pump
Jet
Speed
Concen.
Holes
Hole
Rate
Vel
Length
Temp
Airgap
(fpm)
S.S.F.*
Source
Polymer
Solvent
% Solids
(in.)
L/d
Ml/min
Fpm
(ft)
(° C.)
(in.)
WIND-UP
Ex. 1
α(1-3) glucan acetate
TFA/H 2 O 100/8 w/w
35
0.005
2
0.08
20
14
−1
0.5
58
2.9
Ex. 2
α(1-3) glucan
SAPONIFIED
Ex. 3
α(1-3) glucan acetate
TFA/CH 2 Cl 2 60/40 v/v
25
0.005
2
0.04
10.36
13
9
0.5
36
3.5
Ex. 4
α(1-3) glucan
SAPONIFIED UNDER
TENSION
Ex. 5
α(1-3) glucan acetate
TFA/CH 2 Cl 2 60/40 v/v
25
0.005
2
0.04
10.36
13
3
0.5
23
2.2
Ex. 6
α(1-3) glucan acetate
TFA/CH 2 Cl 2 60/40 v/v
20
0.005
5
0.08
20.72
5
17
0
29
1.4
Comp.
α(1-3) glucan acetate
TFA/CH 2 Cl 2 60/40 v/v
15
0.005
4
0.08
20.72
5
18
0
15
0.7
Ex. 1
Comp.
α(1-3) glucan
SAPONIFIED
Ex. 2
Comp.
α(1-4) glucan acetate
CH 2 Cl 2
20
0.005
2
0.08
20
0.91
23
0
15
0.7
Ex. 3
Comp.
α(1-4) glucan acetate
TFA/H 2 O 100/8 w/w
25
0.005
4
0.08
5
1.08
20
0.25
48
2.4
Ex. 4
*Spin Stretch Factor
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This invention pertains to novel fibers made of α(1→;3) polysaccharides, and a process for their production. The fibers of the invention have “cotton-like” properties but can be produced as continuous filaments on a year-round basis. The fibers are useful in textile applications.
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CROSS-REFERENCE TO RELATED APPLICATION
This is a continuation-in-part of copending application Ser. No. 07/861,696, filed Apr. 1, 1992 now U.S. Pat. No. 5,206,251.
BACKGROUND OF THE INVENTION
This invention relates to novel derivatives of 1,5-dideoxy-1,5-imino-D-glucitol having thio or sulfinyl substituents at C-2 and/or C-3, and, more particularly, to the chemical synthesis of these derivatives and intermediates therefor. These compounds are useful for inhibiting glycosidase enzymes and for inhibiting viruses such as lentiviruses.
1,5-dideoxy-1,5-imino-D-glucitol (deoxynojirimycin or DNJ) and its N-alkyl and O-acylated derivatives are known inhibitors of glycosidase enzymes and also inhibitors of viruses such as human immunodeficiency virus (HIV). See, e.g., U.S. Pat. Nos. 4,849,430; 5,003,072; 5,030,638 and PCT Int'l. Appln. WO 87/03903. Several of these derivatives also are effective against other viruses such as HSV and CMV as disclosed in U.S. Pat. No. 4,957,926. In some cases antiviral activity is enhanced by combination of the DNJ derivative with other antiviral agents such as AZT as described in U.S. Pat. No. 5,011,829. Various of these DNJ derivative compounds are antihyperglycemic agents based on their activity as glycosidase inhibitors. See, e.g., U.S. Pat. Nos. 4,182,763, 4,533,668 and 4,639,436. The 2-acetamide derivatives of DNJ also are reported to be potent glycosidase inhibitors by Fleet et al., Chem. Lett. 7, 1051-1054 (1986); and Kiso et al. J. Carbohydr. Chem.10. 25-45 (1991).
Notwithstanding the foregoing, the search continues for the discovery and novel synthesis of new and improved antiviral compounds.
BRIEF DESCRIPTION OF THE INVENTION
In accordance with the present invention, novel derivatives of 1,5-dideoxy-1,5-imino-D-glucitol having thio or sulfinyl substituents at C-2 and/or C-3 are provided. These novel DNJ derivative compounds and various of their intermediates are useful inhibitors of glycosidase enzymes and also have useful antiviral activity as demonstrated against lentivirus. Compounds of this invention are also useful intermediates for the synthesis of antiviral compounds. According to another embodiment of the invention, novel methods of chemical synthesis of these compounds and their intermediates are provided.
The novel C-2 and/or C-3 thio or sulfinyl substituted derivatives of 1,5-dideoxy-1,5-imino-D-glucitol can be represented by the following general structural Formulas I and II.
The compounds of Formula I are in the gluco stereochemical configuration whereas those of Formula II are in the altro stereochemical configuration. ##STR1##
In Formulas I and II, R 1 is a C 1 -C 6 alkyl group, arylalkyl group, aryl, substituted aryl, substituted arylalkyl; R 3 is H or a C 1 -C 8 branched or unbranched alkyl group, alkoxyalkyl, alkenyl, alkynyl, arylalkyl, substituted arylalkyl, or acyl such as alkylacyl, alkenylacyl, alkynylacyl, arylacyl, substituted arylacyl, arylalkylacyl, substituted arylalkylacyl, carbonyl; and R 5 , R 6 and R 7 are independently H or COR 2 where R 2 =alkyl having C 1 -C 6 branched or unbranched alkyl groups, aryl, or alkylaryl.
Preferred compounds of Formula I are the following:
2-Sulfur Derivatives of DNJ
1,5-Dideoxy-1,5-imino-2-S-methyl-4,6-O-(R-phenylmethylene)-2-thio-D-glucitol
1,5-Dideoxy-1,5-imino-2-S-methyl-2-thio-D-glucitol
1,5-Dideoxy-1,5-[[(2-methoxyethoxy)carbonyl]imino]-2-S-phenyl-4,6-O-(R-phenylmethylene)-2-thio-D-glucitol
1,5-Dideoxy-1,5-imino-2-S-phenyl-4,6-O-(R-phenylmethylene)-2-thio-D-glucitol
1,5-Dideoxy-1,5-imino-2-S-phenyl-2-thio-D-glucitol
1,5-(Butylimino)-1,5-dideoxy-2-S-methyl-2-thio-D-glucitol, triacetate
1,5-(Butylimino)-1,5-dideoxy-2-S-methyl-2-sulfinyl-D-glucitol
Preferred compounds of Formula II are the following:
3-Sulfur Derivatives of DNJ
1,5-Dideoxy-1,5-imino-3-S-methyl-3-thio-D-altritol
1,5-Dideoxy-1,5-imino-3-S-phenyl-3-thio-D-altritol
1,5-(Butylimino)-1,5-dideoxy-3-S-methyl-3-thio-D-altritol
The novel synthesis of compounds of Formulas I and II comprises the formation of structural modifications at C2 and C3 of DNJ and the nucleophilic opening of N-carboalkoxy-2,3-anhydro-DNJ.
The starting N-carboalkoxy-2,3-anhydro-DNJ can be chemically synthesized by the four reaction steps shown in the following Reaction Schemes A(1) and A(2) as described in co-pending application Ser. No. 07/861,696, filed Apr, 1, 1992. ##STR2##
The foregoing Reaction Scheme A comprises the following general reaction steps:
(a) The starting material, DNJ (I), is N-acylated with an acylating agent to form a carbamate derivative of DNJ (II);
(b) The hydroxyls at C-4 and C-6 are protected with a hydroxyl protecting agent by acetalization or ketalization to form an acetal or ketal (III);
(c) The hydroxyl at C-2 is protected by regioselective sulfonylation with a sulfonylating agent at C-2 to give the 2-sulfonated intermediate (IV);
(d) A 2,3-anhydro derivative is formed by epoxidation at C-2 and C-3 to give the epoxide intermediate (V).
N-Acylation of DNJ (I) in step (a) can be carried out by conventional N-acylation procedures well known to those skilled in the art. Suitable general procedures for acylation of amines are described in U.S. Pat. No. 5,003,072; March, J. in Avanced Organic Cemistry, Wiley, New York, 1985; Patai, S. (Ed.) in The Chemistry of Amides, Wiley, New York, 1970. For example, DNJ is N-acylated to form carbamate or thiocarbamate using a variety of reagents such as chloroformates (e.g., methyl chloroformate, ethyl chloroformate, vinyl chloroformate, benzyl chloroformate) or dicarbonates (e.g., di-tert-butyl dicarbonate). The reaction of DNJ (I) with anhydrides, chloroformates or dicarbonates is preferentially carried out by dissolving in one or more of polar, protic or dipolar aprotic solvents (such as water, methanol, ethanol, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, or dimethyl sulfoxide) and in the presence of a base (e.g, potassium carbonate, lithium carbonate, sodium carbonate, cesium carbonate, triethylamine, pyridine, 4-dimethylaminopyridine, diisopropylethylamine, 1,8diazabicyclo[5,4,0]undec-7-ene). N-Acylation is preferentially carried out by reacting DNJ (I) with alkyl or aryl chloroformate in solvents such as DMF or aqueous sodium bicarbonate at 20°-50° C. to give the product (II).
Protection of the hydroxyl groups at C-4 and C-6 in step (b) to give acetal or ketal derivative (III) can be carried out by conventional hydroxyl protection procedures such as those described, e.g., in U.S. Pat. No. 5,003,072 and in Greene, T. W., and Wuts, P. G. M., Protective Groups in Organic Synthesis, Wiley, New York, 1991. The cyclic acetals and ketals are formed by the reaction of 4,6-dihydroxy compound (II) with an aldehyde or a ketone in the presence of an acid catalyst. Illustrative carbonyl (or carbonyl equivalents such as dimethyl acetal or dimethyl ketal) compounds useful in this reaction are acetone, acetaldehyde, methyl phenyl ketone, benzaldehyde, 4-methoxybenzaldehyde, 2,4-dimethoxybenzaldehyde, 4-dimethylaminobenzaldehyde, 2-nitrobenzaldehyde, 2,2,2-trichloroacetaldehyde (chloral) and acetophenone. The acid catalysts suitable for this reaction are, e.g., para-toluene sulfonic acid, cat. HCl, cat. sulfuric acid, FeCl 3 , ZnCl 2 , SnCl 2 and BF 3 -ether, and the reaction is carried out in the presence of aprotic solvents such as methylene chloride, 1,2-dimethoxyethane, dioxane, dimethylformamide, dimethylacetamide or dimethylsulfoxide. Thus paratoluene sulfonic acid is added to a solution of benzaldehyde dimethyl acetal in organic medium, e.g., dimethylformamide, and reacted with N-acyl-DNJ (II) at 20°-65° C. to give the product (III).
The selective protection of the hydroxy group at C-2 in compound (III) in step (c) can be carried out by regioselective sulfonylation to give the sulfonate (IV). For example, compound (III) is conveniently refluxed with dibutyltinoxide in solvents (such as benzene, toluene, xylene, methanol or ethanol and the like) to form a homogeneous solution. The stannylene intermediate is then reacted with p-toluenesulfonyl chloride to give tosylate (IV). Other sulfonyl chlorides such as benzenesulfonyl chloride, 4-bromobenzenesulfonyl chloride, 4-nitrobenzenesulfonyl chloride, methanesulfonyl chloride, 2,6-dimethylbenzenesulfonyl chloride, 1-naphthylenesulfonyl chloride, and 2-naphthylenesulfonyl chloride can also be used in this reaction.
The epoxide intermediate (V) is readily prepared in step (d) by treatment of the sulfonate (IV) with base such as sodium hydride, potassium hydride, lithium hydride, cesium carbonate, potassium carbonate and potassium tert-butoxide using aprotic or dipolar aprotic solvents such as dimethylformamide, dimethylacetamide, dimethylsulfoxide, dimethoxyethane, tetrahydrofuran, dioxane, diethyl ether, dibutyl ether and tert-butyl methyl ether.
In accordance with a preferred embodiment of the invention, the compounds of Formulas I and II can be chemically synthesized by the sequence of reactions shown in the following generic Sulfur Reaction Schemes B, C and D in which, illustratively, R 1 , R 2 , R 3 and R 4 are independently C 1 -C 4 alkyl groups or phenyl, R 5 is OR 6 and R 6 is CH 2 CH 2 OCH 3 , W is OCH 2 Ph or OMe, X is H and V is OC(CH 3 ) 3 . Alternatively, V in Reaction Scheme B can be, e.g., any of the following: carbamate such as t-butyloxycarbonyl, 9-fluorenyloxycarbonyl, benzhydryloxycarbonyl, cyclopentyloxycarbonyl, cyclohexyloxycarbonyl, piperidinoxycarbonyl; acyl such as formyl, acetyl, propionyl, butyryl, isobutyryl, s-butyryl, phenylacetyl, chloroacetyl, and acetoacetyl; trifluoroacetyl; or aryl-or alkylsulfonyl such as p-toluenesulfonyl. ##STR3##
Illustratve Reaction Conditions
Illustrative reaction conditions for carrying out the synthesis steps of Reaction Schemes B-D are as follows:
A nitrogen acyl group in compound 1 can be removed in step a by base hydrolysis at a temperature of from about 40° to 100° C. to give the novel compound 2. Illustrative bases suitable for this reaction are aqueous sodium hydroxide, lithium hydroxide or potassium hydroxide with or without the presence of organic solvents such as methanol, ethanol, ethylene glycol, acetonitrile and dioxane. The carbamates can also be cleaved by other reagents such as sulfur nucleophiles (e.g., sodium thiomethoxide and lithium thiopropoxide), iodotrimethylsilane, lithium peroxide, or hydrazine. Benzyl or substituted benzyl carbamates can be removed by base hydrolysis as described above or by catalytic hydrogenation in an atmosphere of hydrogen in the presence of a noble metal catalyst such as palladium or platinum at a pressure of from one to 50 atmospheres, in a single or mixed solvent(s) such as ethanol, ethyl acetate, toluene, or tetrahydrofuran, or by hydrogenation in an inert atmosphere in the presence of a hydrogen donor such as cyclohexene, cyclohexadiene, or ammonium formate, using a solvent such as ethanol or methanol or the solvents above and a noble metal catalyst as described above.
A different nitrogen protecting group can be introduced, if desired, in step b to give 3 by acylation of 2 to form an amide, carbamate, urethane, or thiocarbamate using a variety of reagents such as acyl halides (e.g., acetyl chloride, propionyl bromide, benzoyl chloride or butyryl chloride), anhydrides (e.g., acetic anhydride, propionic anhydride or butyric anhydride), chloroformates (e.g., methyl chloroformate, ethyl chloroformate, vinyl chloroformate, benzyl chloroformate, 3,3,3-trichloroethyl chloroformate), or dicarbonates (e.g., di-t-butyl dicarbonate). Suitable general procedures for acylation of amines are described in March, J. in Advanced Organic Chemistry, Wiley, New York, 1985; Patai, S. (Ed.) in The Chemistry of Amides, Wiley, New York, 1970. These reactions can be carried out in non-polar, aprotic solvents such as ethers (e.g., diethyl ether, tetrahydrofuran, dioxane, dimethoxyethane, dibutyl ether, t-butyl methyl ether), halogenated solvents (e.g., dichloromethane, chloroform, carbon tetrachloride, 1,2-dichloroethylene), hydrocarbon solvents (e.g., benzene, toluene, hexane), or aprotic dipolar solvents (e.g., dimethylformamide, dimethyl acetamide, dimethyl sulfoxide), and in the presence of a base (e.g., pyridine, 2,6-lutidine, triethylamine, potassium carbonate, aqueous sodium hydroxide, lithium carbonate, cesium carbonate, 4-dimethylaminopyridine, diisopropylethylamine, 1,8-diazabicyclo[5,4,0]undec-7-ene). N-Acylation is preferentially carried out by reacting compound 2 with a dicarbonate in pyridine as solvent at about -20° to 80° to give the product 3.
The opening of the epoxide ring in 3 (Reaction Scheme B) shown in step c to give gluco and altro products 4 and 5 can be achieved by reaction with an alkali metal thioalkoxide or arylthioxide, e.g. sodium thiomethoxide, lithium thiomethoxide, potassium thiomethoxide, calcium thiomethoxide, sodium thiophenoxide, in a hydroxylic solvent such as ethanol, methanol, isopropanol, or 2-methoxy-ethanol, or in a dipolar aprotic solvent such as dimethylformamide or dimethyl sulfoxide, at a temperature of from about 25° to 125° C. The alkali metal thiol salt can be preformed if desired or generated in situ. Such a reaction is well known in the literature as described in, e.g., Chemical Communications, 706 (1968).
Other suitable alkali metal thiol salts for use in the epoxide opening reaction to give sulfur substituted 1,5-iminosugars are the following compounds:
benzenemethanethiol, sodium salt
2,4-dichlorobenzenemethanethiol, sodium salt
3,4-dichlorobenzemethanethiol, sodium salt
p-methoxybenzenemethanethiol, sodium salt
o-methylbenzenemethanethiol, sodium salt
m-methylbenzenemethanethiol, sodium salt
p-methylbenzenemethanethiol, sodium salt
o-nitrobenzenemethanethiol, sodium salt
m-nitrobenzenemethanethiol, sodium salt
p-nitrobenzenemethanethiol, sodium salt
4-chlorobenzenemethanethiol, potassium salt
sodium p-chlorothiophenoxide
sodium 4-bromothiophenoxide
sodium p-t-butylthiophenoxide
sodium 4-fluorothiophenoxide
sodium p-hydroxythiophenoxide
sodium 4-methoxythiophenoxide
sodium m-trifluoromethylthiophenoxide
cyclohexyl mercaptan, sodium salt
cyclopentyl mercaptan, sodium salt
allyl mercaptan, sodium salt
n-butyl mercaptan, sodium salt
sec-butyl mercaptan, sodium salt
t-butylmercaptan, sodium salt
2-chloroallylmercaptan, sodium salt
n-hexylmercaptan, sodium salt
isopropylmercaptan, sodium salt
1-mercapto-2-propanol, sodium salt
methallylmercaptan, sodium salt
n-propylmercaptan, sodium salt
2-naphthalenethiol, sodium salt
2-phenylethylmercaptan, sodium salt
The opening of the epoxide ring in a nitrogen-unsubstituted compound such as 2 (Reaction Scheme D) to give gluco and altro products 25 and 26, respectively, can be carried out as described above for compound 3.
Simultaneous deprotection of the hydroxyl groups in compounds 4 and 5 along with the deprotection of the nitrogen protecting group V--C═O (Reaction Scheme B) where the group V--C═O is acid labile, such as t-butyloxycarbonyl or 3,4-dimethoxybenyloxycarbonyl can be accomplished by acid hydrolysis with an organic or mineral acid such as p-toluenesulfonic acid, hydrochloric acid, sulfuric acid, trifluoromethanesulfonic acid, in a solvent such as anhydrous ethanol or methanol or other solvents mentioned hereinbefore.
Selective deprotection of the hydroxyl groups in a compound such as 19 where R 3 is not an acid labile group to give 20 is accomplished in step n by acid hydrolysis where the acids and solvents are as described above for deprotection of compounds 4 and 5.
Deprotection of nitrogen in a compound such as 20 in which the protecting group is not acid labile can be accomplished by hydrolysis in water optionally containing a cosolvent such as ethanol, methanol, ethylene glycol, dioxane, or tetrahydrofuran, or in the absence of water and in a solvent or solvents as described above containing a base (e.g., sodium hydroxide, lithium hydroxide, lithium peroxide, potassium hydroxide), and the like. When the protecting group is, e.g., p-toluenesulfonyl, deprotection can be carried out by using sodium in liquid ammonia. Groups such as formyl and acetoacetyl can be removed by treatment with, e.g., hydroxylamine or phenylhydrazine. The chloroacetyl group can be removed with thiourea in a suitable solvent such as those mentioned hereinbefore.
Alkylation of nitrogen in compound 6 as shown in step e of Reaction Scheme A to give compound 7 can be accomplished by reductive amination of 6 using an aldehyde in the presence of a reducing agent such as sodium cyanoborohydride, sodium borohydride, borane pyridine complex, borane tetrahydrofuran complex, and the like, in a solvent such as ethanol, methanol, acetic acid, trifluoroacetic acid, or tetrahydrofuran, in the presence or absence of water. Additionally, alkylation can be achieved by reaction with an alkyl halide, such as an alkyl chloride, alkyl bromide, or alkyl iodide, in the presence or absence of a catalyst such as tetraalkylammonium iodide or a silver salt, and in the presence of a base, such as ,e.g., potassium carbonate, pyridine, triethylamine, and the like, and in a solvent such as acetone, methyl ethyl ketone, acetonitrile, tetrahydrofuran, or alcohols such as ethanol or methanol, or in a dipolar aprotic solvent such dimethylformamide or dimethyl sulfoxide.
In addition alkylation on nitrogen can be accomplished by reduction of an amide compound such as 4 where V=alkyl, aryl, alkylaryl, cycloalkyl, alkylcycloalkyl, and the like, using a reducing agent such as lithium aluminum hydride, sodium cyanoborohydride, borane pyridine complex, borane tetrahydrofuran complex, borane dimethyl sulfoxide complex, and the like, in a solvent such as tetrahydrofuran, diethyl ether, dioxane, ethanol, methanol, or in a mixture of such solvents.
Acylation of the hydroxyl groups, in compound 7 as shown in step f of Reaction Scheme B to give peracylated, or optionally partially acylated compounds such as 8, can be performed (see, e.g., Greene, T. W., and Wuts, P. G. M., Protective Groups in Organic Synthesis, 2nd Ed.,Wiley, New York, 1991) by reaction of compound 7 with an acylating agent to form esters (such as acetate, chloroacetate, dichloroacetate, trichloroacetate, methoxyacetate, phenoxyacetate, 4-chloroacetate, isobutyrate, pivaloate, benzoate, propionate, butyrate, and the like), and carbonates (such as methyl, ethyl, 2,2,2-trichloroethyl, isobutyl, vinyl, allyl, phenyl, benzyl, and the like) using acid chlorides, anhydrides, and chloroformates. Acylation can also be performed using the carboxylic acid in the presence of a carbodiimide (e.g., dicyclohexylcarbodiimide, 3-(N,N-dimethylaminopropyl)ethylcarbodiimide), optionally in the presence of an activating agent such as N-hydroxybenzotriazole or N-hydroxysuccinimide. The acylation reactions can be carried out in non-polar, aprotic solvents such as ethers (e.g., diethyl ether, tetrahydrofuran, dioxane, dimethoxyethane, dibutyl ether, t-butyl methyl ether), halogenated solvents (e.g., dichloromethane, chloroform, carbon tetrachloride, 1,2-dichloroethylene), hydrocarbon solvents (e.g., benzene, toluene, hexane), or aprotic dipolar solvents (e.g., dimethylform;amide, dimethyl acetamide, dimethyl sulfoxide), and in the presence of a base (e.g., pyridine, 2,6-lutidine, triethylamine, potassium carbonate, aqueous sodium hydroxide, lithium carbonate, cesium carbonate, 4-dimethylaminopyridine, diisopropylethylamine, 1,8-diazabicyclo[5,4,0]undec-7-ene).
Oxidation of the sulfur atom in 8 as shown in step g of Reaction Scheme B to give the mixture of epimeric sulfoxides 9 is performed by treatment of the sulfide 8 with one equivalent of an oxidizing agent (e.g., m-chloroperoxybenzoic acid, peracetic acid, potassium peroxymonosulfate, hydrogen peroxide, and other methods as disclosed in, e.g., Tetrahedron. 1986, 42, 5459), in solvents such as acetone, acetic acid, methanol, ethanol, dichloromethane, ethyl acetate, dimethylformamide, 2-alkoxyethanol, and water.
Oxidation of compound 8 using an excess of oxidizing agent (more than three equivalents) using oxidants and solvents as described above (and described in Tetrahedron, 1986, 42, 5459) proceeds to give the sulfone N-oxide 11 as shown in step i.
The O-acyl groups in compound 9 are removed by hydrolysis in basic or acidic conditions to give the free triol 10 as illustrated in step h. Cleavage of the O-acyl groups is achieved by exposure of the compound to sodium, lithium, or potassium hydroxide in water or alcohol or a mixture of water and alcohol, or by exposure to a solution of sodium alkoxide in alcohol, or by exposure to a solution of an organic base such as triethylamine or quaternary ammonium hydroxide in water or alcohol or a mixture of water and alcohol, or by exposure to acid in a solvent as described above (e.g., hydrochloric or sulfuric acids).
Deoxygenation of the N-oxide in 11 to give 12 as shown in step j is accomplished by treatment of the N-oxide with a trisubstituted phosphine (e.g. triphenylphosphine or tri-p-tolylphosphine, tri-n-butylphosphine) in a solvent (e.g., acetic acid) at a temperature of from about 25° C. to 120° C. as described in, e.g., Angewandte Chemie. 68, 480 (1956).
Cleavage of the O-acyl groups in compound 12 to give 13 as described in step k is achieved as described above for compound 9.
The foregoing reaction conditions for carrying out the synthesis of Reaction Schemes B-D are further exemplified in specific Examples 5-27 as follows:
Example 5--The N-carbobenzoxy group in the product of Example 4 is removed such as by cleavage with, e.g., cyclohexene.
Example 6--The product of Example 5 is N-acylated with a dicarbonate such as, e.g., di-tert-butyl-dicarbonate.
Example 7--The epoxide in the product of Example 6 is opened by reaction with an alkali metal thiomethoxide to give a mixture of thio-substituted isomeric alcohols.
Example 8--The product of Example 4 is reacted with an alkali metal thiomethoxide to give a mixture of thio-substituted compounds (1, 2, 3 and 4).
Example 9--The hydroxyl protecting group at C4 and C6 of product compound of Example 8 is removed by acid cleavage of acetal or ketal.
Example 10--The N-carbamate group in the product of Example 9 is removed by basic cleavage.
Example 11--The product of Example is N-alkylated such as with, e.g., butyraldehyde.
Example 12--The hydroxy protecting group at C4 and C6 and the N-BOC group of product compound 2 of Example 7 are removed by acid cleavage.
Example 13--The altritol product of Example 12 is N-alkylated such as with, e.g., butyraldehyde.
Example 14--The product of Example 5 is reacted with a thiomethoxide to give a mixture of 2- and 3-thio-substituted compounds.
Example 15--The product of Example 4 is reacted with thiophenol to give a mixture of 4 thio-substituted compounds (1, 2, 3 and 4).
Example 16--The hydroxyl protecting group at C4 and C6 of product compound of Example 15 is removed by acid cleavage of acetal or ketal.
Example 17--The N-carbamate group in the product of Example 16 is removed by basic cleavage.
Example 18--The product of Example 17 is N-alkylated such as with, e.g., butraldehyde.
Example 19--The epoxide in the product of Example 6 is opened by reaction with alkali metal thiophenoxide to qive a mixture of thio-substituted isomeric alcohols 1 and 2.
Example 20--The N-butyloxycarbinol group in product compound of Example 19 is removed by acid cleavage.
Example 21--The product of Example II is O-acylated at the free hydroxyl groups such as with, e.g., acetic anhydride.
Example 22--The 2-thio-substituted product of Example 21 is converted to the corresponding 2-sulfinyl-substituted compound by reaction with about one equivalent of m-chloroperoxybenzoic acid.
Example 23 The O-acyl groups in the product of Example 22 are removed by cleavage with triethylamine.
Example 24 The 2-thio-substituted product of Example 21 is converted to a 2-sulfonyl-substituted compound by reaction with about four equivalents of m-chloroperoxybenzoic acid.
Example 25--The N-butylimino, N-oxide group in the product of Example 24 is converted to the N-butylimino group by reaction with triphenylphosphine.
Example 26--The O-acylated groups in the product of Example 25 are removed by cleavage with triethylamine.
Example 27--The hydroxyl protecting group at C4 and C6 of product compound of Example 15 is removed by cleavage of acetal or ketal.
In standard biological tests, the novel compounds of this invention have been shown to have inhibitory activity against the human immunodeficiency Virus (HlV) and/or against visna virus and/or against glucosidase enzymes.
Inhibitory activity against HIV-i was shown by tests involving plating of susceptible human host cells which are syncytium-sensitive with and without virus in microculture plates, adding various concentrations of the test compound, incubating the plates for 9 days (during which time infected, non-drug treated control cells are largely or totally destroyed by the virus), and then determining the remaining number of viable cells with a colorometric endpoint.
Inhibitory activity against visna virus was shown by a conventional plaque reduction assay. Visna virus, a lentivirus genetically Very similar to the AIDS virus, is pathogenic for sheep and goats. See Sonigo et al., Cell 42. 369-382 (1985); Haase, Nature 322. 130-136 (1986). Inhibition of visna virus replication in vitro as a useful model for HIV and its inhibition by test compounds has been described by Frank et al., Antimicrobial Agents and Chemotherapy 31(9), 1369-1374 (1987).
Inhibitory activity aainst α and β-glucosidase enzymes was determined by conventional in vitro assays for these enzymes as described in U.S. Pat. No. 4,973,602. These assays involve spectrophotometric measurement of the release of -nitrophenol from the substrate p-nitrophenylglycoside in the presence and absence of the test compound and comparison against a control standard that contains a known inhibitor of the enzyme.
DETAILED DESCRIPTION OF THE INVENTION
The following detailed examples will further illustrate the invention although it will be understood that the invention is not limited to these specific examples or the details described therein. ##STR4##
Preparation of 1,5-dideoxy-1,5-[{(phenylmethoxy)carbonyl}imino]-D-glucitol (2): To a stirred solution of 1-deoxynojirimycin (1) (100 g, 0.6i mol) in saturated aqueous sodium bicarbonate (1000 ml), benzyl chloroformate (95%, 121 g, 0.67 ol) was added dropwise at room temperature. After stirring at room temperature for 18 hr, the solution was extracted once with methylene chloride (300 ml) to remove any unreacted benzyl chloroformate. The aqueous layer was then extracted several times with ethyl acetate to give a total of 2.5-3 liters of the extract.The organic layer was then dried (Na 2 SO 4 ), filtered and concentrated to give (2) a white solid (98.57 g, 54%), mp 10°-2° C., Anal calcd. for C 14 H 19 NO 6 C, 56.56, H, 6.44, N, 4.71 Found C, 56.33, H, 6.38, N, 4.58., 1 H NMR (CD 3 OD) 7.2-7.4 (m, 5H), 5.15 (s, 2H), 4.23 (br m, 1H), 4.05 (br d., J=8 Hz, 1H), 3.87 (dd, J=6, 4 Hz, 1H), 3.78-3.85 (m, 2H), 3.70-3.78 (m, 2H), 3.45 (br d, J=8 Hz, 1H).
EXAMPLE 2 ##STR5##
Preparation of 1,5-dideoxy-1,5-[{(phenylmethoxy)carbonyl}imino[-4,6-O-(R-phenylmethylene)-D-glucitol (3): A mixture of (2) (98.5 g, 0.33 mol) , benzaldehyde dimethyl acetal (65.5 g, 0.43 mol) and p-toluenesulfonic acid (1 g) in a round bottom flask was dissolved in dimethlformamide (400 ml). The flask was connected to a water aspirator and the reaction was heated to 60-65° C. for 4 hr. The reaction mixture was cooled to room temperature and poured into stirred ice-water (1200 ml) containing sodium bicarbonate (14 g). The white solid formed was filtered, washed with cold water and dried. Recrystallization using hexane/ethyl acetate gave 3 (96.2 g, 54%) as pure white solid, mp 147-48° C., Anal calcd. for C 21 H 23 NO 6 C, 65.44, H, 6.02, N, 3.63 Found C, 65.15, H, 5.93, N, 3.49. IR (KBr) 3420, 1715, 1450, 1425, 1395, 1380, 1365, 1090cm -1 ; 1 H MR (C 030 D) 7.28-7.53 (m, 10H), 5.61 (s, 1H), 5.14 (s, 2H), 4.77 (dd, J=11, 4.6 Hz, 1H), 4.38 (t, J=11 Hz, 1H), 4.16 (dd, J=13.4, 4.2 Hz, 1H), 3.5-3.7 (complex m, 3H), 3.35 (td, J =11, 4.6 Hz), 2.97 (dd, J=13.4, 9.3 Hz, 1H); 13 C NMR (CD 3 OD) 156.7, 139.4, 138.0, 129.9, 129.7, 129.3, 129.2, 129.1, 127.6, 102 8, 81.9, 77.5, 71.5, 70.6, 68.6, 55.9 and 50.5; MS (CI, NH 3 , m/e) 386 (M+1).
EXAMPLE 3 ##STR6##
Preparation of 1,5-dideoxy-1,5[{(phenylmethoxy)carbonyl}im:ino]-4,6-0-(R-phenylethylene)-D-glucitol, 2-(4methylbenzenesulfonate) (4): A mixture of diol 3 (46.3 g, 0.12 mol) and di-n-butyltin oxide (3I.l g, 0.125 mol) in methanol (300 ml) was refluxed for 2 hr. The methanol was removed, toluene was added and removed under vacuum. The residue was dissolved in methylene chloride (300 ml) and triethylamine (20 ml, 0.144 mmol). After cooling to 0° C., p-toluenesulfonyl chloride (25.2 g, 0.132 mmol) was added. The reaction was stirred at 0° C. for 30 min and then warmed to 20° C. After stirring for 3 hr, the reaction was quenched by adding saturated aqueous sodium bicarbonate. The organic layer was separated and washed with water, 0.5M KHSO 4 and water successively. The organic layer was dried (Na 2 SO 4 ), filtered and concentrated. The residue was chromatographed (silica gel, hexane/ethyl acetate 7/3) to give pure 4 (50.27 g, 77%) as white solid, mp 115-17° C., Anal calcd. for C 28 H 29 NO 8 S: C, 62.32, H, 5.42, N, 2.66 Found C, 62.65, H, 5.40, N, 2.62. 1 H NMR (CDCl 3 ) 7.82 (d, J=7.8 Hz, 2H), 7.35-7.50 (m, l0H), 7.31 (d, J=7.8 Hz, 2H), 5.51 (s, 1H), 5.12 (s, 2H), 4.76 (dd, J=11.4, 4.5 Hz, 1H), 4.38 (ddd, J=9.3, 7.6, 4.8 Hz, 1H), 4.32 (dd, J=11.4, 9.5 Hz, 1H), 4.31 (dd, J=13.6, 4.8 Hz, 1H), 3.78 (dt, J=2.6, 9.4Hz, 1H), 3.59 (t, J=9.4 Hz, 1H), 3.26 (ddd, J=11.4, 9.4, 4.5 Hz, 1H), 3.04 (dd, J=13.6, 9.3 Hz, 1H) 2.63 (d, J=2.6 Hz, 1H), 2.41 (s, 3H); 13 C NMR (CDCl 3 ) 154.8, 145.2, 137.0, 135.8, 133.2, 129.8, 129.3, 128.7, 128.4, 128.3, 128.1, 126.2, 101.8, 79.9, 78.1, 73.9, 69.2, 67.8, 54.2, 47.1 and 21.7; MS (m/e) 546 (M+Li).
EXAMPLE 4 ##STR7##
Preparation of 2,3-anhydro-1,5-dideoxy1,5-[{(phenylmethoxy)carbonyl}imino]-4,6-O-(R-phenylmethylene)-D-mannitol (5): Sodium hydride (2.79 g, 60% dispersion in mineral oil, 69.66 mol) was placed in a flask under argon and washed three times with dry hexane. The residue was suspended in dry THF (300 ml) and to this a solution of 4 (37.6 g, 69.66 mmol) in THF (100 ml) was added slowly. After stirring for 18 hr, the reaction was quenched by adding water. The organic layer was extracted with ethyl acetate and washed with saturated aqueous sodium bicarbonate and brine. After drying (sodium sulfate) and filtration, the organic layer was concentrated and recrystallized using cyclohexane to give pure 5 (19.2 g, 75%) as white solid, mp 104-5° C., Anal calcd. for C 21 H 21 NO 5 C, 68.64, H, 5.77, N, 3.81 Found C, 68.21, H, 5.84, N, 3.67. 1 H NMR (CDCl 3 ) 7.53-7.67 (m, 10H), 5.67 (s, 1H), 5.16 (s, 2H), 4.76 (broad s, 1H), 4.59 (d, J=15 Hz, 1H), 4.08 (d, J=10 Hz, 1H), 4.02 (dd, J=11.4, 4 Hz, 1H), 3.46 (dd, J=15, 0.9 Hz, 1H), 3.40 (d, J=3 Hz, 1H), 3.25 (d, J=3 Hz, 1H), 3.10 (dt, J=4, 10 Hz, 1H); 13 C NMR (CDCl 3 ) 156.2, 137.8, 136.6, 129.7, 129.1, 128.9, 128.8, 128.5, 126.6, 102.8, 73.0, 70.4, 68.0, 56.0, 54.7, 50.4 and 46.6;MS (cI, NH 3 , m/e) 368 (M+H).
EXAMPLE 5 ##STR8##
Preparation of 2,3-Anhydro-1,5-dideoxy-1,5-imino-4,6-R-phenylmethylene-D-mannitol To a solution of 500 mg (1.36 mmoles) of the title cbz-protected amine compound of Example 4 in 20 ml of 9:1 absolute ethanol - cyclohexene was added 100 mg of 10% Pd/c. The mixture was stirred at reflux under N2 for 2 hours. After cooling, the mixture was filtered and solvent evaporated to give 324 mg of the title compound (1%). The structure was supported by NMR.
EXAMPLE 6 ##STR9##
Preparation of 2,3-Anhydro-1,5- dideoxy-1,5-[(2-methyl-2-propyloxycarbonyl)imino]-4,6-R-phenylethylene-D-annitol A solution of 324 mg (1.36 mmoles) of the title product of Example 5 and 326 mg (1.50 mmoles, 1.1 eqs.) of di-t-butyl dicarbonate in 10 ml of pyridine was stirred at room temperature for 2.0 hours. After evaporation of solvent, the residue was partitioned between ethyl acetate /10% aqueous copper sulfate solution, the organic phase was washed with 10% aqueous copper sulfate solution, with water, and with brine, dried over sodium sulfate, and concentrated. Chromatography of the residue over silica gel using 25% ethyl acetate/hexanes as eluent gave the title compound, 144 mg (31%). The structure was supported by NMR.
EXAMPLE 7 ##STR10##
Preparation of 1,5-Dideoxy-1,5-[(2-methyl-2-propyloxycarbonyl)imino]-2-S-methyl4,6-O-(R-phenyl-methylene)-2-thio-D-glucitol 1 and 1,5-Dideoxy-1,5-[(2-methyl-2-propyloxycarbonyl)iino]-3-S-methyl-4,6-O-(R-phenylmethylene)-3-thio-D-altritol 2 A solution of 142 mg (0.426 mmole) of the title product of Example 6 and 149 mg (2.13 mmoles, 5.0 eqs) of sodium thiomethoxide in 5ml of 2-methoxyethanol was stirred at reflux for 0.5 hour. After cooling, the mixture was partitioned between ethyl acetate/water, the aqueous layer was extracted twice with ethyl acetate, the combined organic extracts were washed with water and with brine, dried over sodium sulfate, and concentrated. Radial chromatography of the residue over silica gel (2mm layer thickness, elution with 25% ethyl acetate/hexanes) gave 76 mg of the glucitol product 1 (47%) and 43 mg of the altritol product (26%) (total yield=73%). The structures were supported by NMR.
EXAMPLE 8 ##STR11##
Preparation of 1,5-Dideoxy-1,5-[[(2-methoxyethoxy)carbonyl]imino]-2-S-methyl-4,6-O-(R-phenylmethylene)-2-thio-D-glucitol 1
Preparation of 1,5-Dideoxy-1,5-[[(2-methoxyethoxy)carbonyl]imino]-3-S-methyl-4,6-O-(R-phenylmethylene)-3-thio-D-altritol 2
Preparation of 1,5-Dideoxy-1,5-imino-2-S-methyl-4,6-O-(R-phenylethylene)-2-thio-D-glucitol 3
Preparation of 1,5-Dideoxy-1,5-iino-3-S-methyl-4,6-O-(R-phenylmethylene)-3-thio-D-altritol 4
A solution of b 1.53g (4.15 mmoles) of the title compound of Example 4 and 1.46 g (20.8 mmoles) of sodium thiomethoxide in 20ml of 2-methoxyethanol was refluxed for 1.0 hour. After cooling, the mixture was partitioned between ethyl acetate/water, the aqueous further extracted with two portions of ethyl acetate, the combined extracts washed with brine and dried over sodium sulfate. After concentration, chromatography of the residue over silica gel using a gradient of 50-70% ethyl acetate/hexanes gave 410 mg (26%) title compound and 29 mg (1.8%) title compound 2, then eluting with 10% methanol/ethyl acetate gave 286 mg (24%) title compound 1 and 35 mg (3%) title compound 4. The structures were supported by NMR.
For 3: Anal. for CH 14 H 19 NO 3 S (MW 281.38): Calc'd.: C, 9.77;, H, 6.81; N, 4.98. Found: C, 59.65; H, 6.85; N, 5.00.
For 4: Anal. for C 14 H 19 NO 3 S·1/8 H 2 O (MW 283.63): Calc'd.: C, 59.31; H, 6.84; N, 4.94. Found: C, 59.15; H, 6.86; N, 4.92.
EXAMPLE 9 ##STR12##
Preparation of 1,5-Dideoxy-1,5-[[(2-methoxyethoxy)carbonyl]imino]-2-S-methyl-2-thio-D-glucitol
A solution of 400 mg (1.04 mmole) of the title compound 1 of Example 8 and 40 mg (0.21 mmole, 20 mole %) of p-toluenesulfonic acid monohydrate in 18 ml of ethanol was refluxed overnight. After cooling and addition of 0.25 ml of triethylamine the mixture was directly eluted from silica gel using 5% methanol/ethyl acetate as eluent to give the title compound, 260 mg (85%). The structure was supported by NMR.
EXAMPLE 10 ##STR13##
Preparation of 1,5-Dideoxy-1,5-imino-2-S-methyl-2-thio-D-glucitol
A solution of 260 mg (0.881 mmoles) of the title compound of Example 9 and 400 mg of potassium hydroxide in 10 ml of methanol was refluxed overnight. Direct chromatography of the mixture over silica gel using 25% methanol/2.5% ammonium hydroxide/72.5% ethyl acetate as eluent gave the title compound, 96 mg (56%).Anal. for C 7 H 15 NO 3 S·3/4 H 2 O (MW 206.78): Calc'd.: C, 40.66; H, 8.04; N, 6.80. Found: C, 40.46; H, 7.65; N, 6.99. 13 C NMR (D2O) d 74.82, 71.95, 60.47, 60.34, 47.75, 47.23, 11.98. 1H NMR (400 MHz) (D2O) d 4.84 (HOD), 3.86 (dd, J=11, J=4, 1H), 3.75 (dd, J=12, J=4, 1 H), 3.41 (m, 3H), 2.78 (m, 2H), 2.66 (m, 1H), 2.16 (s, 3H).
EXAMPLE 11 ##STR14##
Preparation of 1,5-(Butylimino}-1,5-dideoxy-2-S-ethyl-2-thio-D-glucitol
To a mixture of 93 mg (0.482 mmole) of the title compound of Example 10, 85 ml of butyraldehyde, and 250 mg of activated 4 Å molecular sieves in 1.6 ml of methanol and 79 ml of acetic acid was added 32 mg of sodium cyanoborohydride. After stirring overnight at room temperature, the mixture was filtered through Celite and concentrated. The residue was chromatographed over silica gel using 50/50 methanol/ethyl acetate as eluent. Appropriate fractions were concentrated, dissolved in 50/50 trifluoroacetic acid/water, then evaporated. The residue in 50/50 methanol/water was passed through a basic ion exchange column eluting with 50/50 methanol/water, and then through an acidic ion exchange column, first washing with waterthen eluting with 50/50 methanol/water, 0.5M in ammonium hydroxide. After concentration, the residue was triturated with ethyl acetate to give the title compound, 76 mg (63%) as a white crystalline solid. Anal. for C 11 H 23 NO 3 S (MW 249.38): Calc'd.: C, 52.97; H, 9.29; N, 5.62. Found: C, 52.69; H, 9.30; N, 5.57.
EXAMPLE 12 ##STR15##
Preparation of ,5-Dideoxy-1,5-imino-3-S-ethyl-3-thio-D-altritol
A solution of the second title compound 2 of Example 7 (840 mg, 2.99 mmoles) and 682 mg (3.59 mmoles) of p-toluenesulfonic acid monohydrate in 60 ml of 95% ethanol was refluxed overnight. Another 136 mg (0.716 mmole) of p-toluenesulfonic acid monohydrate was added and refluxing continued for 6 hours. After cooling, basic ion exchange resin was added, the mixture was stirred for a few minutes, filtered, and concentrated. Crystallization of the residue from methanol gave the title compound, 365 mg, as a white crystalline solid, M.P. 182° C.
Anal.: Calc'd. for C 7 H 15 NO 3 S (MW 193.27): C, 43.50; H, 7.82; N, 7.25. Found: C, 43.41; H, 8.01; N, 7.26.
EXAMPLE 13 ##STR16##
Preparation of 1,5-(Butylimino)-1,5-dideoxy-3-S-methyl-3-thio-D-altritol
To a solution of 141 mg (0.731 mmoles) of the title amine compound of Example 12, 109 ml (105 mg, 1.46 mmoles, 2.0 eqs) butyraldehyde, and 500 mg of 4sieves in 2.5 ml of methanol and 120 μl of acetic acid was added 48 mg (0.76 mmole, 1.04 eqs) of sodium cyanoborohydride. After stirring overnight at room temperature, the mixture was filtered through celite and concentrated.
Chromatography of the residue over silica gel using 10% methanol/2.5% ammonium hydroxide/87.5% ethyl acetate as eluent gave the title compound, 101 mg (64%). Anal. for C 11 H 23 NO 3 S·1/4 H 2 O (MW 253.88): Calc'd.: C, 52.03; H, 9.33; N, 5.520 Found: C, 51.90; H, 9.30; N, 5.42.
EXAMPLE 14 ##STR17##
Preparation of 1,5-Dideoxy-1,5-imino-2-S-methyl-4,6-O-(R-phenylmethylene)-2-thio-D-glucitol 1 and
Preparation of 1,5-Dideoxy-1,5-imino-3-S-methyl-4,6-O-(R-phenylmethylene)-3-thio-D-altritol 2 A solution of 486 mg (2.09 mmoles) of the title compound of Example 5 and 732 mg (10.5 mmoles, 5.0 eqs) of sodium thiomethoxide in 21 ml of 2-methoxyethanol was stirred at reflux for 1.0 hour. After cooling, the mixture was partitioned between ethyl acetate/water, the aqueous extracted twice with ethyl acetate, the combined extracts washed with brine, and dried over sodium sulfate. Chromatography of the residue over silica gel using a gradient of 0-10% methanol/ethyl acetate as eluent gave 50 mg (8.5%) of title compound 1, and 210 mg (36%) of title compound 2. The structures were confirmed by NMR.
EXAMPLE 15 ##STR18##
Preparation of 1,5 Dideoxy 1,5-[[(2-ethoxyethoxy)carbonyl]imino]-2-S-enyl-4,6-O-(R-phenylmethylene)-2-thio-D-glucitol 1
Preparation of 1,5-Dideoxy-1,5-[[(2-methoxyethoxy)carbonyl]imino]-3-S-henyl-4,6-O-(R-phenylmethylene)-3-thio-D-altritol 2
Preparation of 1,5-Dideoxy-1,5-imino]-2-S-phenyl-4,6-O-(R-phenylmethylene)-2-thio-D-glucitol 3
Preparation of 1,5-Dideoxy-1,5-imino-3-S-phenyl-4,6-O-(R-phenylmethylene)-3-thio-D-altritol 4
Sodium thiophenoxide was generated in situ by adding 5.1 ml (49.7 mmoes) of thiophenol to a solution of 1.20 g (52.2 mmoles) of Na in 50 ml of 2-methoxyethanol, bringing the solution to brief reflux, and cooling. To this solution was added 3.05 g (8.31 mmoles) of the title epoxide compound (5) of Example 4, and the resulting mixture was refluxed for 1.0 hour. After cooling, the mixture was partitioned between ethyl acetate/water, the aqueous was extracted twice with ethyl acetate, the combined extracts were washed with brine, dried over sodium sulfate and concentrated. Chromatography over silica gel using 50/50 ethyl acetate/hexanes as eluent gave title compound 1 as a white solid, 1.04 g (28%), using 75% ethyl acetate as eluent gave title compound 2 as a white foam, 315 mg (8.5%), using ethyl acetate as eluent gave title compound as a white solid, 443 mg (16%), and using 25% MeOH/Ethyl acetate as eluent gave title compound 4, 647 mg (23%) as a white solid. 1 - Anal. for C 23 H 27 NO 6 S (MW 445.54): Calc'd.: C, 62.02; H, 6.11; N, 3.14. Found: C, 61.97; H, 6.27; N, 3.14. 3 - Anal. for C 19 H 2 1NO 3 S (MW 343.45): Calc'd.: C, 66.43; H, 6.16; N, 4.08. Found: C, 66.22; H, 6.16; N, 4.14. The structures of title compounds and were supported by NMR.
EXAMPLE 16 ##STR19##
Preparation of 1,5-Dideoxy-1,5-[[(2-methoxyethoxy)carbonyl]imino]-2-S-phenyl-2-thio-D-glucitol A solution of 1.04 g (2.33 mmoles) title compound 1 of Example 15 and 89 mg (20 mole%) of p-toluenesulfonic acid monohydrate in 38 ml of ethanol was refluxed for 3 hours. After cooling, the solution was concentrated and the residue chromatographed over silica gel using 5% methanol/ethyl acetate as eluent to give 755 mg (95%) of the title compound.
Anal. for C 16 H 23 NO 6 S (MW 357.43): Calc'd.: C, 53.78; H, 6.49; N, 3.92. Found: C, 54.08; H, 6.60; N, 3.95.
EXAMPLE 17 ##STR20##
Preparation of 1,5-Dideoxy-1,5-imino-2-S-phenyl-2-thio-D-glucitol A solution of 227 mg (0.636 mmole) of the title compound of Example 16 and 282 mg of potassium hydroxide in 6 ml of methanol was refluxed for 4.0 hours. After cooling, 1 ml of acetic acid was added and the solvent removed. Chromatography of the residue over silica gel using 25% methanol/2.5% ammonium hydroxide/72.5% ethyl acetate as eluent gave the title compound, 45 mg (26%) as a pale yellow solid. Anal. for C 12 H 17 NO 3 S·H 2 O (MW 273.36): Calc'd.: C, 52.78; H, 7.00; N, 5.12. Found: C, 52.50; H, 6.61; N, 5.38.
EXAMPLE 18 ##STR21##
Preparation of 1,5-(Butylimino)-1,5-dideoxy-2-S-phenyl-2-thio-D-glucitol To a mixture of 170 mq (0.667 mmoles) of the title compound of Example 17, 96 mg (1.3 mmoles, 2.0 eqs) of butyraldehyde, 300 mg of 4 Å molecular sieves, 2.2 ml of methanol, and 110 μl of acetic acid was added 44 mg (0.69 mmoles, 1.04 eqs) of sodium cyanoborohydride, and the resulting mixture was stirred overnight at room temperature. The mixture was filtered through Celite, concentrated, then chromatographed over silica gel eluting with 25% methanol/2.5% ammonium hydroxide/72.5% ethyl acetate. Appropriate fractions were concentrated and the residue taken up in 50/50 trifluoroacetic acid/water, then evaporated. Ion exchange chromatography over a basic resin eluting with 25% methanol/water followed by a basic resin eluting with 25% methanol/0 5M aqueous ammonium hydroxide and then lyophilization gave the title compound, 48 mg (23%) as a white, crystalline solid. Anal. for C 16 H 25 NO 3 S·1/4 H 2 O (MW 315.95): C, 60.83; H, 8.14; N, 4.43. Found: C, 60.44; H, 7.92; N, 4.55.
EXAMPLE 19 ##STR22##
To a solution of sodium thiophoxide (prepared by adding 1.10 g, 10.0 mmoles of thiophenol to a solution of 230 mg, 10.0 mmoles of sodium in 20 ml of 2-methoxyethanol followed by stirring at room temperature for 15 min) was added 666 mg (2.00 mmoles) of the title epoxide compound of Example 6 as a solid., and the mixture was stirred at reflux for 1.0 hour. After cooling, the mixture was partitioned between ethyl acetate/water, the aqueous was extracted twice with ethyl acetate, the combined extracts were washed with brine and dried over sodium sulfate. The solution was concentrated and the residue chromatographed over silica gel using a gradient of 25-50% ethyl acetate/hexanes as eluent to give 490 (55%) of 1 and 360 mg (4I%) of (total yield=96%). The structures were supported by NMR.
EXAMPLE 20 ##STR23##
Preparation of 1,5-Dideoxy-1,5-imino-2-S-phenyl-2-thio-D-glucitol
A solution of 430 mg (0.968 mmole) of one of the title compounds, 1, of Example 19 and 221 mg (1.16 mmole, 1.2 mole %) p-toluenesulfonic acid monohydrate in 20 ml of ethanol was refluxed for 3.0 hour. After cooling, 1 ml of triethylamine was added and the mixture concentrated. The residue was taken up in 40% methanol/water and passed through a basic ion exchange column. The solvent was evaporated to give the title compound, 252 mg (102%) as a white solid. The structure was supported by NMR and by comparison with the title product of Example 17.
EXAMPLE 21 ##STR24##
Preparation of 1,5-(Butylimino)-1,5-dideoxy-2-S-methyl-2-tio-D-lucitol, triacetate
A solution of 1.80 g (7.23 mmoles) of the title compound of Example 11 in 50 ml of pyridine and 20 ml of acetic anhydride was refluxed for 15 min. After cooling, the mixture was concentrated. The residue was taken up in ethyl acetate, washed with aqueous copper sulfate solution, with water, with brine, and dried over sodium sulfate. The solution was concentrated and chromatographed over silica gel using 30% ethyl acetate/hexanes as eluent to give the title compound, 1.72 g (63%). Anal. for C 17 H 29 NO 6 S (MW 375.49): Calc'd.: C, 54.38; H, 7.78; N, 3.73. Found: C, 54.22; H, 7.76; N, 3.83.
EXAMPLE 22 ##STR25##
Preparation of 1,5-(Butylimino)-1,5 dideoxy-2-S-methyl-2 sulfinyl D glucitol, triacetate
To an ice cold stirred solution of the title compound of Example 21 in 24 ml of dichloromethane was added 285 mg (1.32 mmoles, 1.1 eqs) of 85% m-chloroperoxybenzoic acid as a solid. The ixture was stirred overnight while warming to room temperature and then directly chromatographed over silica gel eluting the sulfoxide with 10% methanol/2.5% ammonium hydroxide/87.5% ethyl acetate followed by a second chromatography over silica gel using 5% 2-propanol/2.5% ammonium hydroxide/92.5% chloroform as eluent to give the title compound, 123 mg (26%) as an oil. Anal. for C 17 H 29 NO 7 S (MW 391.49): Calc'd.: C, 52.16; H, 7.47; N, 3.58. Found: C, 52.18; H, 7.52; N, 3.14.
EXAMPLE 23 ##STR26##
Preparation of 1,5-(Butylimino)-1,5-dideoxy-2-S-methyl-2-sulfinyl-D-glucitol A solution of 67 mg (0.171 mmole) of the title compound of Example 22 in a mixture of 8 ml of methanol, 1 ml of water, and 1 ml of triethylamine was stirred overnight at room temperature. The solution was evaporated to give the title compound, 43 mg (96%). Anal. for C 11 H 23 NO 4 S (MW 265.38): Calc'd.: C, 49.77; H, 8.73; N, 5.28. Found: C, 49.58; H, 8.71; N, 5.16.
EXAMPLE 24 ##STR27##
Preparation of 1,5-[Butyl(hydroxyiino)]-1,5-dideoxy-2-S-methyl-2-sulfonyl-D-glucitol, triacetate To an ice cold solution of 450 mg (1.20 mmoles) of the title compound of Example 21 in 24 ml of dichloromethane was added 830 mg (4.80 mmoles, 4.0 eqs) of 85% m-chloroperoxybenzoic acid in one portion as a solid. The mixture was stirred overnight while permitting to warm to room temperature. Direct chromatography over silica gel using 10% 2-propanol/2% ammonium hydroxide/87.5% chloroform as eluent gave the title compound (180 mg) as a pale tan solid. The product was reacted directly further as is. The structure was supported by NMR.
EXAMPLE 25 ##STR28##
Preparation of 1,5-(Butylimino)-1,5-dideoxy-2-S-methyl-2-sulfonyl-D-glucitol, triacetate A mixture of 263 mg (0.631 mmole) of the title compound of Example 24 and 182 mg (0.694 mmole, 1.1 eqs) of triphenylphosphine in 7 ml of acetic acid was stirred at reflux for 1.0 h then cooled. After removal of solvent by azeotropic distillation with toluene, the residue was chromatographed over silica gel using 55% ethyl acetate/hexanes to give the title compound, 177 mg (70%). The structure was supported by NMR.
EXAMPLE 26 ##STR29##
Preparation of 1,5-(Butylimino)-1,5-dideoxy-2-S-methyl-2-sulfonyl D-glucitol A solution of 137 mg (0.337 mmole) of the title compound of Example 25 in 10 ml of 8:1:1 methanol/water/triethylamine was kept overnight at room temperature. After evaporation of the solvent, the residue was chromatographed over silica gel using 10% methanol/2.5% ammonium hydroxide/87.5% ethyl acetate as eluent. Trituration of the product with ethyl acetate gave 45 mg (47%) as a white crystalline solid. Anal. for C 11 H 23 NO 5 S (MW 281.37): Calc'd.: C, 46.94; H, 8.24; N, 4.98. Found: C, 46.77; H, 8.16; N, 4.95.
EXAMPLE 27 ##STR30##
Preparation of 1,5-Dideoxy-1,5-imino-3-S-phenyl-3-thio-D-altritol A solution of 100 mg (0.292 mmole) of the title compound 4 of Example 15 and 67 mg (0.35 mmole, 1.2 eqs) of p-toluenesulfonic acid monohydrate in 6 ml of ethanol was refluxed overnight After cooling, the mixture was concentrated and then passed through a basic ion exchange column using 25% methanol/water as eluent. The appropriate fractions were washed with hexane, then concentrated to give the product as white solid. Anal. for C 12 H 17 NO 2 S·1/4 H 2 O(MW 259.89): Calcd.: C, 55.47; H, 6.79; N, 5.39. Found: C, 55.08; H, 6.63; N, 5.25.
EXAMPLE 28
Various illustrative compounds synthesized above were tested for inhibition of visna virus in vitro in a plaque reduction assay (Method A) or for inhibition of HIV-1 in a test which measured reduction of cytopathogenic effect in virus-infected syncytium-sensitive Leu-3a-positive CEM cells grown in tissue culture (Method B) as follows:
Method A
Cell and virus roaoation
Sheep choroid plexus (ScP) cells were obtained from American Type culture collection (ATCC) catalogue number CRL 1700 and were routinely passaged in vitro in Dulbecco's Modified Eagles (DME) medium supplemented with 20% fetal bovine serum (FBS). SCP cells were passaged once per week at a 1:2 or 1:3 split ratio. Visna was titrated by plaque assay in six-well plates. Virus pools were stored at -70° C.
Plaque reduction assay
SCP cells were cultured in 6-well plates to confluence. Wells were washed two times with serum free Minimal Essential Medium (MEM) to remove FBS. 0.2 ml of virus was added per well in MEM supplemented with 4 mM glutamine and gentamycin. After i hour adsorption, the virus was aspirated from each well. The appropriate concentration of each compound in 5 ml of Medium 199 (M-199) supplemented with 2% lamb serum, 4 mM glutamine, 0.5% agarose and gentamycin was added to each well. Cultures were incubated at 37° C. in a humidified 5% CO 2 incubator for 3-4 weeks. To terminate the test, cultures were fixed in 10% formalin, the agar removed, the monolayers stained with 1% crystal violet and plaques counted. Each compound concentration was run in triplicate. Control wells (without virus) were observed for toxicity of compounds at the termination of each test and graded morphologically from 0 to 4. 0 is no toxicity observed while 4 is total lysing of the cell monolayer.
96 well plate assay
The 96 well plate assay was performed similarly to the plaque assay above with modifications. SCP cells were seeded at 1×10 4 cells per well in 0.1 ml DME medium. When confluent, the wells were washed with serum free MEM and 25 μl of virus added in M-199 supplemented with 2% lamb serum. After I hour, 75 μL of medium containing test compound was added to each well containing virus. After 2-3 weeks incubation the cytopathic effect of the virus was determined by staining with a vital stain. Cell viability was measured by determining stain density using a 96 well plate reader.
Control wells without virus were completed to determine the toxicity of compounds.
Method B
Tissue culture plates were incubated at 37° C. in a humidified, 5% CO 2 atmosphere and observed microscoically for toxicity and/or cytopathogenic effect (CPE). At 1 hour prior to infection each test article was prepared from the frozen stock, and a 20 μl volume of each dilution (prepared as a 10× concentration) was added to the appropriate wells of both infected and uninfected cells.
Assays were done in 96-well tissue culture plates. CEM cells were treated with polybrene at a concentration of 2 μg/ml, and an 80 μl volume of cells (1×10 4 cells) was dispensed into each well. A 100 μl volume of each test article dilution (prepared as a 2× concentration) was added to 5 wells of cells, and the cells were incubated at 37° C. for 1 hour. A frozen culture of HIV-1, strain TYVL-III B , was diluted in culture medium to a concentration of 5×10 4 TCID 50 per ml, and a 20 μl volume (containing 10 3 TCID 50 of virus) was added to 3 of the wells for ech test article concentration. This resulted in a multiplicity of infection of 0.1 for the HIV-1 infected samples. A 20 μl volume of normal culture medium was added to the remaining wells to allow evaluation of cytotoxicity. Each plate contained 6 wells of untreated, uninfected, cell control samples and 6 wells of untreated, infected, virus control samples.
On the 9th day post-infection, the cells in each well were resuspended and a 100 μl sample of each cell suspension was removed for use in an MTT assay. A 20 μl volume of a 5 mg/ml solution of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) was added to each 100 μl cell suspension, and the cells were incubated at 37° C. in 5% CO 2 for 4 hours. During this incubation MTT is metabolically reduced by living cells, resulting in the production of a colored formazan product. A 100 μl volume of a solution of 10% sodium dodecyl sulfate in 0.01N hydrochloric acid was added to each sample, and the samples were incubated overnight. The absorbance at 590 nm was determined for each sample using a Molecular Devices V max microplate reader. This assay detects drug-induced suppression of viral CPE, as well as drug cytotoxicity, by measuring the generation of MTT-formazan by surviving cells.
Table 1, below, sets forth the results of the foregonig assays for visna virus inhibition and HIV inhibition by illustrateive compounds prepared in the foregoing Examples.
TABLE 1______________________________________Anti-viral Activity of Sulfur-AnalogsExample Visna Virus HIVCompound No. Inhibition Inhibition______________________________________Ex. 8 EC.sub.50 = 28.8 μg/mlCompnd. -3Ex. 12 EC.sub.50 = 30.5 μg/mlEx. 13 83% @ 0.05 mM 76% @ 0.05 mM 65% @ 0.005 mMEx. 15 59% @ 1.0 μMCompnd. -1Ex. 15 48% @ 10 μg/mlCompnd. -3Ex. 17 64% @ 1.0 mMEx. 21 30.4% @ 100 μg/mlEx. 23 51% @ 0.5 mMEx. 27 15.1% @ 100 μg/ml______________________________________
The compounds of Examples 10 and 17 also effectively inhibited glucosidase enzymes 20% and 64%, respectively, at 1 mM concentration as determined by conventional assays for these enzymes described in U.S. Pat. No. 4,973,602.
The antiviral agents described herein can be used for administration to a mammalian host infected with a virus e.g. visna virus or in vitro to the human immunodeficiency virus, by conventional means, preferaby in formulations with pharmaceutically acceptable diluents and carriers. These agents can be used in the free amine form or in their salt form. Pharmaceutically acceptable salt derivatives are illustrated, for example, by the HCl salt. The amount of the active agent to be administered must be an effective amount, that is, an amount which is medically beneficial but does not present toxic effects which overweigh the advantages which accompany its use. It would be expected that the adult human dosage would normally range upward from about one mg/kg/day of the active compound. The preferable route of administration is orally in the form of capsules, tablets, syrups, elixirs and the like, although parenteral administration also can be used. Suitable formulations of the active compound in pharmaceutically acceptable diluents and carriers in therapeutic dosage from can be prepared by reference to general texts in the field such as, for example, Remington's Pharmaceutical Sciences, Ed. Srthur Osol, 16th ed., 1980, Mack Publishing Co., Easton, Pa.
Various other examples will be apparent to the person dkilled in the art after reading the present disclosure without departing from the spirit and scope of the invention. It is intended that all such other examples be included within the scope of the appended claims.
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Novel derivatives of 1-deoxynojirimycin are disclosed which have thio or sulfinyl substituents at C-2 or C-3. These compounds are useful inhibitors of lentiviruses such as visna virus and human immunodeficiency virus. Methods of chemical synthesis of these derivatives and intermediates therefor are also disclosed.
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CROSS-REFERENCE TO RELATED APPLICATION(S)
[0001] The present non-provisional patent application claims the benefit of priority of U.S. Provisional Patent Application No. 61/041,325 (Robin Coger and Mei Niu), filed on Apr. 1, 2008, and entitled “RADIAL FLOW BIOREACTOR,” the contents of which are incorporated in full by reference herein.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] The present invention was developed through private support from the Whitaker Foundation, Grant No. TF-05-0001, and in part through government support from the National Institutes of Health (NIH), Grant No. R01 DK058503-01A1. Therefore, the government has certain rights in the present invention.
FIELD OF THE INVENTION
[0003] The present invention relates generally to a bioreactor assembly and associated methods. More specifically, the present invention relates to a bioreactor assembly that utilizes and incorporates a medium flow, a plurality of customizable concentrically arranged framed membrane cartridges for cellular attachment and the like, and a modular design that allows for selected framed membrane cartridges to be removed, studied, cryo-preserved, and/or replaced in process, without otherwise disrupting the reactions taking place in the bioreactor assembly.
BACKGROUND OF THE INVENTION
[0004] In general, a bioreactor is a vessel in which a chemical reaction or process is carried out that involves an organism or biochemically active substance derived from an organism. In other words, bioreactors differ from conventional chemical reactors in that they support and control biological entities. Therefore, bioreactors must be designed to provide a higher degree of control over upsets and contaminations than conventional chemical reactors, they must provide a higher degree of selectivity, they must accommodate a wider range of reaction rates, etc. Furthermore, the evaluation of the integrity of the cell population contained within the bioreactor throughout the course of the bioreactor's use is required. While this often done by analyzing samples of the bioreactor's flow, there are benefits to being able to analyze the cell population of the bioreactor over time. The reaction parameters that must be controlled and optimized include substrate selection, amount, and configuration; cellular selection, patterning, culturing, and protection; water availability; oxygen availability; nutrient availability; temperature; pH; gas evolution; product and byproduct removal; flow rate, etc. Advantageously, bioreactors are used in the following exemplary applications, among others: bioartificial organs, organ and tissue simulation, drug discovery and testing, cell/tissue manufacturing, antibody production, and, in general, the study and use of biochemical reactions (including those involving organisms, substances derived from or affecting organisms, cellular structures, etc.). It will be readily apparent to those of ordinary skill in the art that there are other applications not specifically included in this list, both existing and future.
[0005] Tissue loss and organ failure are unfortunately suffered by patients on a daily basis. Yet for acute clinical cases, transplantation is the only end stage treatment currently available. In reality, the supply of donated tissues and organs is very limited, and interim options are needed. The use of bioreactors that provide an environment for maintaining cells while enabling them to perform key functions offers hope as an interim treatment. In such applications, these bioreactors are essentially bridges to transplantation. In the future, they may serve as substitutes for transplantation as well.
[0006] In the case of bio-artificial liver (BAL) devices, for example, a bioreactor is used to support viable hepatocytes, such that these hepatocytes may express high levels of differentiated function. BAL devices are typically classified as one of several types: capillary hollow fiber devices, suspension and encapsulation chambers, and perfused beds and scaffolds. Capillary hollow fiber devices have been rapidly developed for clinical trials. Unfortunately, these devices have the inherent physical limitations of constrained total mass diffusion distances, reduced capacities for cellular mass maintenance, and non-uniform cellular distributions. Suspension and encapsulation chambers provide a uniform micro-environment and the potential for scale up, but they offer poor cellular stability (e.g. suspension chambers) and barriers to nutrient transport (e.g. encapsulation chambers). In both cases, cells are exposed to unacceptably high shear forces. Perfused beds and scaffolds solve some of these problems, but, unfortunately, experience non-uniform perfusion, the clogging of membrane pores, and may also expose cells to unacceptably high shear forces. All of these devices make it difficult, if not impossible, to remove a fraction of the cellular space in process, without otherwise disrupting the reactions taking place.
[0007] Thus, what is still needed in the field is a bioreactor design that solves some or all of these problems.
[0008] In general, tissue function is modulated by the communication of cells with extra-cellular matrices, soluble factors, and other cells. The technologies used to explore the latter interaction (e.g., cell-to-cell)—such as micro-fabrication, micro-patterning, and the like—have typically been applied to flat plate in vitro cultures. Because flat plate in vitro cultures offer low surface area-to-volume ratios, it is difficult to scale them up to the cellular masses associated with bioreactors. Micro-fabrication and micro-patterning techniques, such a photolithography, photo-patterning, micro-contact printing, inkjet printing, laser guided direct writing, and cell spraying have been used to develop heterogeneous two-dimensional and three-dimensional co-cultures. Although co-culturing hepatocytes, the liver parenchymal cell, with support cells positively impacts hepatocyte function, for example, micro-fabrication and micro-patterning techniques may not readily be implemented in any of the BAL devices described above.
[0009] Thus, what is still needed in the field is a bioreactor design that provides an adaptable cellular space, among other things.
BRIEF SUMMARY OF THE INVENTION
[0010] In various exemplary embodiments, the present invention provides a bioreactor assembly that utilizes and incorporates a quadrant-specific medium (e.g., blood, plasma, blood equivalent (e.g., nutrient media), or other fluid designed to interact with the biological entities of the bioreactor) flow; a plurality of customizable concentrically arranged framed membrane cartridges for the packing of cells, tissues, and the like; and a modular design that allows for selected framed membrane cartridges to be removed, studied, cryo-preserved, and/or replaced in process, while only minimally disrupting the reactions taking place in the bioreactor assembly. In other words, the bioreactor assembly of the present invention incorporates a novel cellular support structure that is modular in nature. It is capable of accommodating functional sized tissues (e.g. consisting of about than 2×10 8 cells of 30-micron diameter in its initial embodiment) and a wide range of attachment dependent cells. Advantageously, the bioreactor assembly of the present invention is fully scalable and may be stored, for off-the-shelf availability.
[0011] In one exemplary embodiment, the present invention provides a bioreactor assembly, including: a housing internally defining a plurality of reaction chambers; a medium flow supply line associated with each of the plurality of reaction chambers, wherein the medium flow supply line associated with each of the plurality of reaction chambers is operable for delivering a medium flow to each of the plurality of reaction chambers; and one or more framed membrane cartridges selectively disposed within each of the plurality of reaction chambers, wherein each of the one or more framed membrane cartridges disposed within each of the plurality of reaction chambers is operable for holding a biochemically active material that is reacted when exposed to the medium flow. The housing includes a perimeter wall, a bottom wall, and one or more internal walls that collectively define the plurality of reaction chambers. Preferably, the one or more internal walls prevent fluid communication among the plurality of reaction chambers. Preferably, the medium flow delivered to each of the plurality of reaction chambers is a medium flow. The one or more framed membrane cartridges disposed within each of the plurality of reaction chambers are disposed substantially concentrically about a central axis of the housing. The one or more framed membrane cartridges disposed within each of the plurality of reaction chambers are disposed in a substantially vertical orientation. Each of the one or more framed membrane cartridges includes one or more frame members and one or more membrane substrates selectively disposed within and retained by the one or more frame members. The biochemically active material is selectively disposed one of on and between the one or more membrane substrates. Optionally, one or more of the one or more membrane substrates are substantially porous, such that fluid transport may take place there through. The bioreactor assembly also includes a rack that engages the housing and to which the one or more framed membrane cartridges are attached. The bioreactor assembly further includes a cover operable for selectively engaging and environmentally sealing the housing.
[0012] In another exemplary embodiment, the present invention provides a bioreactor method, including: providing a housing internally defining a plurality of reaction chambers; associating a medium flow supply line with each of the plurality of reaction chambers, wherein the medium flow supply line associated with each of the plurality of reaction chambers is operable for delivering a medium flow to each of the plurality of reaction chambers; and selectively disposing one or more framed membrane cartridges within each of the plurality of reaction chambers, wherein each of the one or more framed membrane cartridges disposed within each of the plurality of reaction chambers is operable for holding a biochemically active material that is reacted when exposed to the medium flow. The housing includes a perimeter wall, a bottom wall, and one or more internal walls that collectively define the plurality of reaction chambers. Preferably, the one or more internal walls prevent fluid communication among the plurality of reaction chambers. Preferably, the medium flow delivered to each of the plurality of reaction chambers is a medium flow. The one or more framed membrane cartridges disposed within each of the plurality of reaction chambers are disposed substantially concentrically about a central axis of the housing. The one or more framed membrane cartridges disposed within each of the plurality of reaction chambers are disposed in a substantially vertical orientation. Each of the one or more framed membrane cartridges includes one or more frame members and one or more membrane substrates selectively disposed within and retained by the one or more frame members. The biochemically active material is selectively disposed one of on and between the one or more membrane substrates. Optionally, one or more of the one or more membrane substrates are substantially porous, such that fluid transport may take place there through. The bioreactor method also includes providing a rack that engages the housing and to which the one or more framed membrane cartridges are attached. The bioreactor method further includes providing a cover operable for selectively engaging and environmentally sealing the housing.
[0013] In a further exemplary embodiment, the present invention provides a bioreactor assembly, including: a housing internally defining a plurality of reaction chambers; a medium flow supply line associated with each of the plurality of reaction chambers, wherein the medium flow supply line associated with each of the plurality of reaction chambers is operable for delivering a medium flow to each of the plurality of reaction chambers; and one or more framed membrane cartridges selectively disposed within each of the plurality of reaction chambers, wherein each of the one or more framed membrane cartridges disposed within each of the plurality of reaction chambers is operable for holding a biochemically active material that is reacted when exposed to the medium flow, and wherein one or more of the one or more framed membrane cartridges disposed within a given reaction chamber may be selectively removed without disrupting reactions taking place in other reaction chambers. Preferably, the bioreactor assembly is maintained at predetermined environmental conditions. The bioreactor assembly is used in an application selected from the group consisting of a bioartificial organ application, an organ modeling application, an organ simulation application, a drug discovery application, a drug testing application, a cell/tissue manufacturing application, an antibody production application, and another biochemical reaction application.
[0014] It should be noted that, although the bioreactor assembly of the present invention is described herein largely in terms of liver support applications, its broader applicability is not so limited, as those of ordinary skill in the art will readily understand and appreciate. Many applications that are currently known and that have yet to be developed are contemplated by the present invention. At present, bioreactors are used in artificial organ, organ simulation, drug discovery and testing, and, in general, biochemical reaction (including those involving organisms, substances derived from organisms, cellular structures, etc.) applications, as examples. Quite simply, the bioreactor assembly of the present invention may be used in any application that a bioreactor of any type is suitable for.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The present invention is illustrated and described herein with reference to the various drawings, in which like reference numbers are used to denote like assembly components/method steps, as appropriate, and in which:
[0016] FIG. 1 is a fully exploded perspective view of one exemplary embodiment of the bioreactor assembly of the present invention, highlighting the housing, framed membrane cartridges, rack, and cover of the bioreactor assembly;
[0017] FIG. 2 is a partially exploded perspective view of the bioreactor assembly of FIG. 1 , highlighting the media transport tubes of the bioreactor assembly;
[0018] FIG. 3 is a partially transparent perspective view of the bioreactor assembly of FIGS. 1 and 2 , highlighting the media transport tube connections of the bioreactor assembly;
[0019] FIG. 4 is a schematic view of an overall environmental system in which the bioreactor assembly of FIGS. 1-3 is implemented;
[0020] FIG. 5 is a perspective view of the framed membrane cartridges and rack of FIGS. 1 and 2 in an assembled configuration;
[0021] FIG. 6 is a planar view of one of the framed membrane cartridges of FIGS. 1 and 5 , highlighting the frame, one or more membranes, and tab structure of the framed membrane cartridge;
[0022] FIG. 7 is a schematic view of one exemplary embodiment of a membrane configuration that may be utilized with the one or more membranes of FIG. 6 ; and
[0023] FIG. 8 is a schematic view of another exemplary embodiment of a membrane configuration that may be utilized with the one or more membranes of FIG. 6 .
DETAILED DESCRIPTION OF THE INVENTION
[0024] Again, the present invention provides a bioreactor assembly that utilizes and incorporates a medium flow, a plurality of customizable concentrically arranged framed membrane cartridges for cellular attachment and the like, and a modular design that allows for selected framed membrane cartridges to be removed, studied, cryo-preserved, and/or replaced in process, without otherwise disrupting the reactions taking place in the bioreactor assembly. In other words, the bioreactor assembly of the present invention incorporates a novel cellular support structure that is modular in nature. It is capable of accommodating functional sized tissues (e.g. consisting of more than 2×10 8 cells of 30-micron diameter) and a wide range of attachment dependent cells. Advantageously, the bioreactor assembly of the present invention is fully scalable and may be stored, for off-the-shelf availability.
[0025] Referring to FIG. 1 , in one exemplary embodiment, the bioreactor assembly 10 of the present invention includes a housing 12 defined by a circumferential wall 14 and a bottom wall 16 . The interior of the housing 12 is divided into multiple reaction chambers 18 by multiple walls 20 . In general, these walls 20 separate these reaction chambers 18 , such that the biochemical reactions taking place in the reaction chambers 18 are isolated from one another. Optionally, in some applications, some or all of the walls 20 could include holes (not illustrated) or the like, such that the reaction chambers 18 would be in fluid communication and the biochemical reactions taking place in given reaction chambers 18 would not be isolated from one another. Preferably, the bioreactor assembly 10 has an overall height of between about 2 inches and about 5 inches, and an overall diameter or width of between about 3 inches and about 6 inches. It will be readily apparent to those of ordinary skill in the field, however, that other suitable dimensions could be utilized, as the bioreactor assembly 10 is fully scalable. Although the housing 12 of the bioreactor assembly 10 is illustrated as a substantially circular structure, it will also be readily apparent to those of ordinary skill in the field that other suitable shapes could be utilized. The housing 12 and other components of the bioreactor assembly 10 may be formed from any material that is compatible with the biochemical reactions taking place within. Exemplary materials include plastic materials and metallic materials, such as polycarbonate (PC) and stainless steel (SS). Preferably, all materials used are autoclavable.
[0026] The bioreactor assembly 10 also includes multiple customizable concentrically arranged framed membrane cartridges 22 for cellular attachment and the like, as described in greater detail below. In a preferred embodiment, each reaction chamber 18 includes multiple framed membrane cartridges 22 . Advantageously, one or more framed membrane cartridges 22 may be removed from one reaction chamber 18 without disrupting the biochemical reactions taking place in other reaction chambers 18 . In this sense, the bioreactor assembly 10 is modular.
[0027] The framed membrane cartridges 22 are selectively attached to a rack 24 , as also described in greater detail below. This rack 24 is selectively disposed within or adjacent to the top portion of the housing 12 , such that the framed membrane cartridges 22 hang in the housing 12 . It will be readily apparent to those of ordinary skill in the field that other means for securing the framed membrane cartridges 22 in the housing 12 could be utilized. For example, the housing 12 could include multiples “slots” within which the framed membrane cartridges 22 are disposed.
[0028] The bioreactor assembly 10 further includes a cover 26 that is used to selectively seal the housing 12 . Again, although the cover 26 of the bioreactor assembly 10 is illustrated as a substantially circular structure, it will be readily apparent to those of ordinary skill in the field that other suitable shapes could be utilized.
[0029] Referring to FIG. 2 , the bioreactor assembly 10 still further includes one or more media transport tubes 28 that selectively pass through one or more holes 30 manufactured into the rack 24 , as well as one or more holes 32 manufactured into the cover 26 , as well as one or more holes 34 manufactured into the bottom wall 16 of the housing 12 . These media transport tubes 28 are operable for carrying one or more reaction media to and away from each of the reaction chambers 18 ( FIG. 1 ), through an inlet at the bottom of each reaction chamber 18 and an outlet at the top of each reaction chamber 18 , as illustrated. Advantageously, the one or more reaction media carried to and away from each of the reaction chambers 18 may be the same reaction media, such that the biochemical reactions taking place in each of the reaction chambers 18 is doing so under similar environmental conditions. The one or more reaction media carried to and away from each of the reaction chambers 18 may also be different reaction media, such that the biochemical reactions taking place in each of the reaction chambers 18 is doing so under different environmental conditions. In order to deliver the reaction media to each of the reaction chambers 18 , the media transport tubes are equipped with appropriate fluid delivery holes or other fluid delivery mechanisms (not illustrated) within each of the reaction chambers 18 . Advantageously, the bioreactor assembly 10 may be operated at full or fractional capacity due to its modular reaction chamber/media transport tube configuration.
[0030] Referring to FIG. 3 , for the ease of connection, the one or more media transport tubes 28 include an inlet port 36 that is selectively connected to a media inlet line 38 and an outlet port 40 that is selectively connected to a media outlet line 42 . Thus, a media flow path is established through the bioreactor assembly 10 .
[0031] It should be noted that the various media illustrated and described herein are typically oxygenated nutrient media, such as blood or plasma equivalents in organ simulation and replacement applications. These media could also include any required to maintain the biochemical reaction(s) of interest.
[0032] Referring to FIG. 4 , in one exemplary embodiment, the bioreactor assembly 10 is connected between a first sample point 44 and a second sample point 46 , each of the sample points 44 and 46 including a valve or the like operable for providing access to the one or more reaction media entering and/or exiting the bioreactor assembly 10 . Oxygen levels and the like may be monitored at these sample points 44 and 46 . The bioreactor assembly 10 is connected to a media reservoir 48 and a media gas exchanger 50 , operable for selectively adding gas to or removing gas from the one or more reaction media. The bioreactor assembly, 10 , the sample points 44 and 46 , the media reservoir 48 , and the media gas exchanger 50 are disposed within an incubator 52 operable for maintain the gas, pressure, and temperature environment of the bioreactor assembly 10 , such that the biochemical reactions taking place therein are maintained. In order to move the one or more transport media, the bioreactor assembly 10 is also connected between a first peristaltic pump 54 and a second peristaltic pump 56 . It will be readily apparent to those of ordinary skill in the field that other overall environmental systems could be utilized.
[0033] Referring to FIG. 5 , again, the bioreactor assembly 10 ( FIGS. 1-4 ) includes multiple customizable concentrically arranged framed membrane cartridges 22 for cellular attachment and the like. In a preferred embodiment, each reaction chamber 18 ( FIGS. 1 and 3 ) includes multiple framed membrane cartridges 22 . Advantageously, one or more framed membrane cartridges 22 may be removed from one reaction chamber 18 without disrupting the biochemical reactions taking place in other reaction chambers 18 . In this sense, the bioreactor assembly 10 is modular.
[0034] The framed membrane cartridges 22 are selectively attached to the rack 24 . The rack 24 is selectively disposed within or adjacent to the top portion of the housing 12 ( FIGS. 1-3 ), such that the framed membrane cartridges 22 hang in the housing 12 . It will be readily apparent to those of ordinary skill in the field that other means for securing the framed membrane cartridges 22 in the housing 12 could be utilized. For example, the housing 12 could include multiples “slots” within which the framed membrane cartridges 22 are disposed.
[0035] Referring to FIG. 6 , in one exemplary embodiment, each of the framed membrane cartridges 22 includes a frame 60 within which one or more membranes 62 are selectively disposed. Optionally, the frame 60 is a two piece frame, the two pieces interlocking such that the one or more membranes 62 are entrapped within the frame 60 . A clip or the like may be used to selectively hold the two pieces together. These membranes 62 act as a substrate for cellular attachment and the like, as described in greater detail below. Preferably, the spacing between adjacent membranes 62 is on the order of a millimeter, although any suitable pacing may be used. The frame 60 includes a tab structure 58 that is configured to engage a corresponding slot 57 ( FIG. 5 ) that is manufactured into the rack 24 ( FIG. 5 ). Again, it will be readily apparent to those of ordinary skill in the field that other means for securing the framed membrane cartridges 22 to the rack 24 could be utilized.
[0036] Referring to FIG. 7 , in one exemplary embodiment, a membrane configuration that may be utilized with the one or more membranes 62 ( FIG. 6 ) includes a substrate 64 , such as a plastic substrate or the like. A first layer 66 , such as a collagen layer or the like, is deposited on the substrate 64 via coating dried type I collagen film or the like. This first layer 66 serves as the attachment layer for a cellular layer 68 or other biochemically active material that carries out the biochemical reactions of interest. A second layer 70 , such as another collagen layer or the like, is deposited on the cellular layer 68 or other biochemically active material via placing type I collagen gel with a thickness of about 500 microns to create a modified sandwich culture configuration or the like. This second layer 70 serves as a protective layer for the cellular layer 68 or other biochemically active material, protecting it from shear forces caused by the adjacent medium flow 72 while allowing nutrient transport there through.
[0037] Referring to FIG. 8 , in another exemplary embodiment, a membrane configuration that may be utilized with the one or more membranes 62 ( FIG. 6 ) includes a first layer 74 , such as a dried collagen layer or the like. Again, this first layer 74 serves as the attachment layer for the cellular layer 68 or other biochemically active material that carries out the biochemical reactions of interest. The second layer 70 , such as the other collagen layer or the like, is deposited on the cellular layer 68 or other biochemically active material via placing type I collagen gel with a thickness of about 500 microns or the like. In this exemplary embodiment, the first layer 74 , the cellular layer 68 or other biochemically active material, and the second layer 70 are “sandwiched” between a first porous membrane 76 and a second porous membrane 78 . These porous membranes 76 and 78 serve as protective layers for the cellular layer 68 or other biochemically active material, protecting it from shear forces caused by the adjacent media flows 72 while allowing nutrient transport there through. The porous membranes 76 and 78 may be, for example, permeable polytetrafluoroethylene (PTFE) membranes of 30 μm thickness and 0.4 μm pore size. Other suitable membranes may be made of cellulose or modified cellulose membrane, collagen patch, polysulfone, or other appropriate tissue scaffold, for example.
[0038] Although two exemplary membrane configurations have been illustrated and described, it will be readily apparent to those of ordinary skill in field that other configurations could be used, both in terms of layer material selection and ordering. In general, membrane materials are selected for their various properties—including pore size, hydrophilicity, hydrophobicity, etc.
Experimental Setup
[0039] PC cartridge frames were machined using a computer numerical control machine. SS cartridge frames were machined using a laser cutter. To prepare the PC cartridge frames for use, they were cleaned using sandpaper and by immersing them in 95% ethanol, then sterilized by autoclaving at 121° C./15 psig using a 30-minute cycle in preparation for tissue culture use. To prepare the SS cartridge frames for use, an initial cleaning was performed to remove all oxide particles and heat tint, followed by a 30-minute soak in a 20% nitric acid bath at 60° C. (i.e. a passivation). To remove the residual acid, the SS cartridge frames were then thoroughly rinsed in de-ionized water. Finally, the SS cartridge frames were sterilized by autoclaving at 121° C./15 psig using a 30-minute cycle in preparation for tissue culture use. Prior to reusing either the PC or SS cartridge frames, fine sandpaper was used to clean their surfaces; followed by autoclaving at 121° C./15 psig using a 30-minute cycle.
[0040] Prior to using the PTFE membranes, the membranes were first autoclaved using a 15-minute liquid cycle at 121° C. Next, the membranes were attached to each cartridge frame using a cyanoacrylate adhesive. The assembled cartridge frame-membrane assemblies were then stored within a bio-safety cabinet for at least 24 hours to allow the cyanoacrylate adhesive to fully cure.
[0041] Before using the cartridge frame-membrane assemblies for tissue culture, they were further sterilized by immersion in 95% ethanol until membranes appeared to be transparent. The cartridge frame-membrane assemblies were then sterilized via immersion in 70% ethanol for a minimum of 1 hour. The cartridge frame-membrane assemblies were then washed three times in saline solution (i.e. 0.9% NaCl), with a 20-minute soak included in the second wash. The cartridge frame-membrane assemblies were then dried in preparation for making the tissue equivalents they would support.
[0042] In order to prepare the bioreactor assembly for use, other critical parts (e.g. the reaction chambers, all connectors, all silicone stoppers, various tubing, as well as parts of the dynamic system) were sterilized prior to use by rinsing them first with 90% ethanol, then with 70% ethanol, then twice with 1× phosphate buffered saline (PBS).
[0043] The circulation system used included a medium reservoir for removing gas bubbles from the medium; a gas exchanger made of gas permeable silastic tubing with a length of 5 m, EDxOD=1.47×1.96 mm; a multi-function meter for documenting the level of dissolved O 2 within the medium and the pH of the nutrient medium; a peristaltic pump coupled to a flow meter for directing the flow of the liquid nutrients; and an incubator for maintaining the bioreactor assembly at 37° C. with 5% CC>2/95% air. The priming volume of the circuit was 320 ml. The tissue culture medium was perfused at a rate of 55-60 ml/min starting on day three post-isolation and was changed on day six and day twelve. The flow rate was checked regularly.
[0044] For each reaction chamber of the bioreactor assembly, the cellular spaces (i.e. the cartridge frame-membrane assemblies) were attached to the rack and suspended vertically. This unique bioreactor design allows for the easy removal of a single (or multiple) cartridge frame-membrane assemblies from the overall system. The design of the cartridge frame/membrane assemblies makes the bioreactor assembly adaptable for use in supporting a wide range of tissue equivalents. As described above and below, the current investigation demonstrated its applicability to a cellular space consisting of hepatocytes sandwiched between two layers of type I collagen, for example. To ensure stabilization of the cells within the cartridge for 24 hours prior to securing them within the bioreactor assembly, the cultures were first incubated for 24 hours within a 100 mm tissue culture dish at 37° C. and 5% CO 2 /95% air; then relocated under sterile conditions to the rack of the bioreactor assembly.
[0045] Specifically, rat hepatocytes were isolated from male Sprague Dawley rats weighing 180-220 g by collagenase perfusion using a method modified from Seglen (1976). The liver was perfused with collagenase solution (140 mg/ml) through the portal vein, and the digested liver was then filtered through a nylon mesh with a pore size of 105 μm. The hepatocytes were then separated from the non-parenchymal cell fractions by centrifugation at 50 g for 3 minutes. The viability of the hepatocytes, evaluated via trypan blue exclusion, was 88-95%. When the cellular viability was below 85%, percoll centrifugation was performed. The hepatocytes were then re-suspended in culture medium containing Dulbecco's Modified Eagle Medium (DMEM) supplemented with 3.7 g of sodium bicarbonate, insulin (500 U/L), glucagon (7 μg/L), epidermal growth factor (20 μg/L), hydrocortisone (7.5 mg/L), penicillin G (10,000 U/ml), streptomycin (10 mg/ml), amphotericin B (25 mg/ml), and 10% fetal bovine serum.
[0046] Static sandwich cultures in (35 mm diameter) tissue culture plates were used as the controls throughout the experiments. The collagen type I gel was first prepared by adding eight parts of 1.1 mg/ml PureCol collagen to one part of 10×DMEM. The pH of the solution was adjusted to 7.4 by adding 0.1 N NaOH or 0.01 N HCl. In the tissue culture plates, 0.5 ml of collagen was coated and incubated for at least one hour at 37° C., 5% C>2/95% air to allow gelation. Then 1 ml of 2.0×10 6 cells/ml hepatocytes were seeded in each tissue culture plate to achieve a seeding density of 2.1×10 5 cells/cm 2 . The medium was then changed after 1 hour to remove unattached cells from the culture. After 24 hours, 0.5 ml of collagen gel was added to each tissue culture plate and allowed to gel for 45 minutes at 37° C. in a 5% CO 2 /95% air incubator. Following this, the culture medium was replaced daily.
[0047] A modified sandwich culture was also used for the cellular space. As compared to the previous static sandwich culture, the membrane of the bottom unit of the cartridge was first coated with a dried collagen film. The collagen film was prepared by diluting the stock Purcol collagen (3.1 mg/ml) 1:4 in 70% ethanol (one part collagen and three parts 70% ethanol) and vortexing to mix. Then, 1 ml of the diluted collagen was evenly coated on the membrane of the bottom unit. After incubating the collagen coated membrane overnight at 37° C., 5% CO 2 , 2 ml of hepatocytes (density: 2.0×10 6 cells/ml) were seeded. The final seeding density of hepatocytes for each cartridge was 2.1×10 5 cells/cm 2 . The medium was changed after 1 hour incubation to remove excess unattached hepatocytes. After 24 hours of culture, 1 ml of collagen gel was added on top of the layer of cells and allowed to gel at 37° C. in a 5% CO 2 /95% air incubator for 45 minutes. It should be noted that, to this point, the membrane of the bottom unit was always exposed to air on its bottom side through the use of supports under the cartridge frames. After fixing the top unit of the cartridge onto the bottom unit (clips were used to close the bottom and top units of the cartridge properly), the cartridge placed in a tissue culture plate, 100 mm in diameter, and 15 ml of medium was added for culture.
[0048] The effectiveness of an individual cartridge in supporting cells was first evaluated using hepatocytes cultured within both static and dynamic systems. In the static culture system, a single cartridge containing hepatocytes was sandwiched between collagen type I gel and placed in a tissue culture plate (100 mm in diameter) and incubated at 37° C., 5% CO 2 /95% air. To maintain the cell culture, 15 ml of cell culture medium was replaced every other day from day 2 on. In the dynamic culture system, two cartridges, which were identical to the hepatocyte supporting cartridges of the static system, were placed in a modified tissue culture plate (100 mm in diameter), retrofitted with an inlet and an outlet to ensure medium flow. This dynamic system was also incubated at 37° C., 5% CO 2 /95% air. 50 ml of culture medium was circulated in the flow circuit, with a flow rate of 30 ml/min, and replaced every other day. Two cartridges were used for the dynamic system to increase the cell number to avoid excessive dilution of the cells' metabolites within the medium. For both the static and dynamic culture systems, 1 ml of supernatant was sampled for cell function analysis from day 3 of the culture.
[0049] To test the effectiveness of the bioreactor design of the present invention in establishing uniform flow circulation within each quadrant chamber, flow visualization studies were performed using a dye dispersion method. In order to visualize the flow, a transparent acrylic chamber was first prototyped in replacement of the polycarbonate translucent chamber of the bioreactor. Then the modified bioreactor was assembled with eight cartridges suspended within the chamber and connected to a water flow circuit. Next, commercially available dye was injected through the inlet, and a sequence of snapshots were taken at 1 minute intervals to document the dye distribution into the quadrant chamber of the bioreactor.
[0050] Changes in urea concentration were quantitatively measured using a urea nitrogen (BUN) kit, based on direct interaction of urea with diacetyl monoxime. The absorbance was measured at 540 nm with a multi-detection microplate reader. Culture medium containing 5.0 mM ammonia chloride was added to the cells in order to evaluate the ammonia clearance ability of the hepatocytes. Furthermore, albumin secretion was measured by a standard competitive enzyme linked immunosorbent assay (ELISA) with the use of purified rat albumin and peroxidase conjugated sheep anti-rat albumin antibody. Briefly, 50 J, g/ml rat albumin was added to 96 well plates and stored at 4° C. for at least 24 hours. The wells were washed with 0.05% Tween-20 in PBS and non-specific binding sites were blocked with Tween-20 at the same time. 50 μl of sheep anti-rat albumin peroxidase conjugate were added to each well and incubated for 24 hours at 4° C. The wells were then washed with 0.05% Tween-20 four times and incubated for 15 minutes with o-phenylenediamine substrate. The reaction was stopped with 8 N sulfuric acid and absorbance was measured at 450 nm with the multi-detection microplate reader. Both the urea and albumin results were calibrated to a standards curve, and concentration values were normalized by the nutrient medium volume, culture time, and number of seeded hepatocytes.
[0051] An important function of hepatocytes is to metabolize thousands of endogenous and exogenous compounds by a large group of heme-containing isoenzymes, i.e cytochrome P450 (CYP). They primarily locate in hepatocytes, within the membranes of the smooth endoplasmic reticulum. For rat primary hepatocytes, CYP1 enzymes are present at a relatively higher level and are readily detectable as compared to other CYP families. Ethoxyresorufin-O-deethylase (EROD) activity has been used as a catalytic monitor of CYP1 enzymes (primarily CYP1A1). Using ethoxyresorufin as the substrate, the rate of resorufin productivity is directly proportional to the EROD activity.
[0052] Sandwich cultures in 24-well plastic culture plates were used as negative and positive controls. CYP1A1/2 was induced by adding 2 μM 3-methylcholanthrene (3MC) to the medium for 48 hours before the EROD assay. Three samples were used to perform each EROD assay. Each cartridge or the culture plate well was incubated in a Hank's Balanced Salt Solution (HBSS) buffer containing 20 mM HEPES and 10 μM dicumarol, which inhibits the secondary metabolism of resorufin. After 10 minutes of incubation, assay buffer containing 5 μM ethoxyresorufin and 10 μM dicumarol was added. After 1 hour of incubation in 5% CO 2 , 95% air at 37° C., the assay buffer was sampled at various time points (5, 15, 25, and 35 min). The cells in the cartridges and in the 24-well culture plates were washed twice with HBSS, fed with fresh medium and returned to either the bioreactor or the incubator. Resorufin fluorescence (with excitation at 530 nm, and emission at 590 nm) was measured using the multi-detection microplate reader. To determine the net resorufin production, a resorufin standard curve (range 2 to 200 pmol) was used. Before serial dilution, the actual concentration of the super stock of resorufin, 200 μM in HEPES (pH9), was checked on each assay date using a spectrophotometer. The actual concentration was calculated using the Beer-Lambert Law, C=A/sL. Where C is the concentration, A is the wavelength, s is the molar absorption coefficient, and L is the width of sample cuvettes (L=1 cm). Three replicates of each resorufin standard were added to a 96-well plate and the average background corrected arbitrary fluorescence units were plotted against the nominal resorufin concentrations to produce the resorufin standard curve and linear regression equation. The resorufin content in each well was plotted against time and a linear regression analysis was performed on each sample well to obtain the slope and estimate the resorufin production rate (pmol/min). The results were normalized by the dilution of medium and number of seeded hepatocytes.
[0053] To evaluate the O 2 environment established within bioreactor assembly, a single quadrant chamber of the bioreactor assembly supporting eight cartridges was used. Tissue culture medium containing 0.2 mM Hypoxyprobe™-1 (Pimonidazole Hydrochloride, Chemicon, Temecula, Calif.) was circulated through the chamber for 4 hours. Meanwhile, three cartridges maintained at an incubator (5% CO 2 , 21% C>2, 37° C.), were used as negative controls, whereas, another three cartridges maintained at the other incubator (5% CO2, 1% C>2, 37° C.) were used as positive controls. Following the 4 hours incubation, samples were fixed in 4% paraformaldeyde (in 1×PBS) for 10 min at 4° C. and stored in PBS until staining. The following immunohistochemical staining protocol was employed, where all steps took place at room temperature and 1×PBS was used for washes. Endogenous peroxidase was blocked with 3% hydrogen peroxide in PBS for 10 minutes. Dako protein block, used to block potential non-specific binding sites in the cell/tissue, was applied for 15 minutes. Samples were then incubated with hypoxyprobe-1 Mab1 conjugated with FITC (clone 3.11.3) at 1:50 for 40 minutes. As the negative controls, no primary antibody was added to the cells. A rocking platform was used with a speed of 30 rpm and 10° tilt angle, to ensure that all the hepatocytes were stained evenly. Anti-FITC Mab conjugated with HRP was used as the secondary antibody at 1:300 for 30 min. Labeling was visualized using liquid diaminobenzidine (DAB) for 5 minutes. Samples were then counterstained with Mayer's haematoxylin and kept in 1×PBS for image analysis on the same day.
[0054] Cell viability was evaluated for hepatocytes within the static and dynamic systems, as compared with the control sandwich cultures on Day 2, Day 7, and Day 11. In each case, an inverted microscope was used to observe hepatocyte morphologies immediately prior to initiating the viability assay. To evaluate the viability of the hepatocytes cultured within the cartridges of the bioreactor assembly, the following procedure was followed. The media was first removed, then a small scissors was used to cut off the membranes from the cartridge. The modified sandwich cultures were then carefully relocated from the cartridges to labeled 60 mm tissue culture plates and incubated for 30 minutes with 1 ml of a viability solution consisting of 2 μM Calcein AM, 4 μM Ethidium Homodimer in media. A rocking platform was used with a speed of 30 rpm and 10° tilt angle to ensure that all the hepatocytes were stained evenly. Next, the cells were fixed with by 10% buffered formalin solution in PBS. Viable and non-viable cells were examined through the confocal microscopy using FITC and Texas red filter sets, respectively. Flouview v 2.1.39 and Metamorph Imaging system were then used to obtain and analyze the fluorescent images.
[0055] Each individual cartridge was first evaluated for the design's effectiveness in supporting hepatocyte viability, differentiation, and liver specific functions. This helped verify whether the cartridge configuration provided a favorable environment for the hepatocytes. Culturing hepatocytes in a traditional sandwich configuration between two layers of gelled extracellular matrix prolongs the time of cultures by displaying polygonal morphology, maintaining cell viability and hepatocyte specific functions up to several weeks. The traditional collagen sandwich culture within 35 mm tissue culture plates was used as the control. The cartridge configuration was tested under both static condition and dynamic condition. Since cell-cell interactions strongly influence hepatocyte function in collagen gel, seeding density was consistently kept as 2.1×10 5 cells/cm 2 in both the controls and cartridges to ensure comparable results.
[0056] First, morphologies of hepatocytes cultured in different conditions were observed daily. Within the cartridge, hepatocytes were sandwiched between a collagen type I dried film treated cartridge membrane and collagen gel, as compared to the traditional sandwich culture configuration. During the first one hour of seeding, hepatocytes attached and started to spread on both the dried collagen film coated cartridge membrane and the collagen gel surface. However, the collagen film coated cartridge membrane resulted in the cells spreading quickly and a better interconnect between neighboring cells within the 24 hours before the second layer of collagen was overlayed during the culture. Similar to the control sandwich cultures, hepatocytes cultured within the cartridges developed and sustained polygonal morphology and exhibited distinct cell-cell borders for more than 11 days both in the static and dynamic systems.
[0057] Next, cell viabilities were evaluated for hepatocytes cultured in the above three conditions on day 2, day 7 and day 11 post-isolation. Cell viability in the cartridges (both in static and dynamic) remained relatively stable during the two week culture period. No significant difference was observed between hepatocyte viability for the controls and cartridge.
[0058] The effectiveness of individual cartridges in supporting hepatocytes was evaluated by comparing the liver specific functions, albumin and urea secretion. Albumin production and urea secretion were measured for both the static and dynamic systems, as compared with the control sandwich culture, throughout the 15 day culture period.
[0059] Albumin is a highly soluble, single polypeptide protein with a molecular weight of 66,000. It has been often measured as an indication of synthetic activity of hepatocytes. Although hepatocytes have 12% higher albumin production rates when cultivated in the static cartridge system (peaking at 67.54±23.56 μg/10 6 cells/day, n=3) than the control (60.24±21.68 μg/10 6 cells/day, n=3), this difference was not statistically significant. Contrastingly, in the dynamic system, hepatocytes significantly increase the albumin secretion rate after Day 5 compared with either the static system or the control (p<0.025). The peak albumin secretion rate for the dynamic system reached an average value of 170.03±22.02 μg/10 6 cells/day (n=3).
[0060] Urea secretion is an indicator of metabolic function of hepatocytes. To evaluate the urea secretion rate of hepatocytes cultured in three conditions, all cultures were spiked with ammonia on Day 7. The urea secretion rate of hepatocytes cultured in the control sandwich culture configuration was highest in the first 3 to 5 days post-isolation and averaged 97.32±6.93 μg/10 6 cells/day (n=3). Secretion rate then further decreased after spiking by ammonia during the subsequent 1 week in culture. For the static culture system of the cartridge, urea secretion rate was stable and higher than the control over the 2 weeks of culture. Adding NH 4 Cl did not cause a big fluctuation in urea the secretion rate of the static system. However, the pattern of urea secretion rate of the dynamic system was significantly different from that of either the control or static system. The peak of the secretion rate was on Day 5 post-isolation and decreased by roughly 40%. After spiked by adding ammonia, the secretion rate firstly increased and then decreased to a stable level during the last 4 days in culture. By circulating medium within the culture system, i.e. the dynamic system, the urea secretion rate was significantly improved compared with either the control or the static system.
[0061] These results confirmed the efficacy of the individual cartridge in supporting hepatocytes to maintain its morphological development and cell survival. Furthermore, the dynamic flow of nutrient media enhances the cellular functional performance. Next, the performance of the bioreactor assembly with a perfusion system was evaluated. As shown from a series of snapshots of dye dispersion within a bioreactor chamber, the dye was initially injected from the bottom outlet. It quickly filled the chamber bottom up. To leave the bioreactor, dye solution was drawn by a peristaltic pump (Q=60 ml/min) through a central tube, which was used as an outlet. The unique flow pattern was therefore created.
[0062] Next, the evaluation of the bioreactor assembly in supporting hepatocytes was performed. Since the pH and O 2 levels are critical to cell survival and functional performance, medium was sampled to monitor these two parameters throughout the two week culture period of each experiment. The pH of the tissue culture medium ranged from 6.9 to 7.5. The ideal physiological range is 7.2 to 7.4, but it did not have a detrimental effect on cell viability.
[0063] O 2 diffusion could be facilitated by increasing the pC>2 by using 95% O 2 plus 5% CO 2 . Nevertheless, to avoid hyperoxia encountered by hepatocytes, 21% O 2 /5% CO 2 and balanced with N 2 was used during the oxygenation of nutrient media. The other way to augment the oxygen transfer rate is to increase the flow rate of the system. Because the unique membrane-frame design protected the encased cellular spaces from shear stress of flow, the flow rate was set at a relatively high value, i.e. 60 ml/min, without disturbing the cells. The dissolved O 2 in the medium was measured at both inlet and outlet of the bioreactor assembly, ranging from 6.6 mg/L to 8.2 mg/L.
[0064] To ensure that the nutritional demands of the contained hepatocytes were met, the oxygen uptake rate (OUR) was also examined. The OUR was calculated as below,
[0000]
OUR
=
(
DO
inlet
-
DO
outlet
)
*
Q
N
[0000] where DO is the dissolved oxygen concentration (mg/L) in the inlet and outlet of bioreactor assembly, Q is the culture medium flow rate (ml/min), and N is the number of cells in the bioreactor.
[0065] Hypoxyprobe™ was used as an alternative approach to test the suitability of oxygen level within the bioreactor. Regions of hypoxia were assessed on Day 2 post-isolation, which is the first day of culture in the cartridge within the bioreactor assembly. After 4 hours of perfusion, hepatocytes located at the bottom region of the bioreactor (close to the inlet) were compared with the cells in the upper region (close to the outlet). As a positive control, hepatocytes were stained with hypoxyprobe-1 after incubation in hypoxic conditions (1% O 2 ) for 4 hours. Contrastingly, for the negative control, hepatocytes were incubated in normoxic conditions (21% O 2 ), which were stained only by the hematoxylin. In comparison to the positive and negative controls, there was no indication of severe hypoxia in the hepatocytes located at either the bottom or the top of the bioreactor assembly. This result suggests that the unique flow pattern of the bioreactor assembly provides a normoxic environment for the cells in the cartridge.
[0066] Evaluation of the success of the bioreactor assembly in supporting the viability and functional performance of its cultured hepatocytes was then performed. During the 15 day culture period, hepatocyte morphologies were documented at various times. Hepatocytes within the perfused bioreactor maintained morphologies similar to that observed for hepatocytes in the individual cartridge in the dynamic culture system. At the end of the 15 day perfusion, cartridges were removed from the bioreactor, and hepatocyte viability was evaluated. The average viability was 84±18% (n=3).
[0067] The albumin production and urea secretion rates achieved by the hepatocytes maintained in the bioreactor were obtained. The secretion rates, normalized by the dilution of the culture medium and number of cells, were comparable to the previous results achieved for hepatocytes in individual cartridges. The culture of hepatocytes within the bioreactor assembly started on Day 2 post-isolation. On Day 6 and Day 12, the media of the chamber and flow circuit were replaced with fresh media containing 5 mM ammonia chloride (NH 4 Cl), which was used to spike hepatocytes cultured with the bioreactor assembly, to evaluate their success in ammonia clearance. The rate of albumin secretion rapidly increased to 126.64±9.54 μg/10 5 cells/day and 110.20±15.61 μg/10 6 cells/day on day 11 and day 15, respectively. The time course of urea secretion during the two weeks of bioreactor perfusion was also obtained. After addition of NH 4 Cl to the tissue culture medium on day 6 and day 12, a progressive increase in urea synthesis was detected.
[0068] The inducibility of EROD was studied by adding 3-MC. Induction was initiated on day 6 and day 12 and was continued for 3 days. EROD activity on day 9 and day 15 were evaluated. The hepatocytes cultured in 24-well culture plates were used as the control for comparison. The resorufin production rates were normalized by the dilution of the incubation buffer and number of cells. On day 3, before adding inducer, the cells both in the plates and bioreactor have very low EROD activity. After the addition of 3-MC, a maximum induction of EROD activity was obtained in both systems and peaked on day 9. The addition of inducer 3-MC had 48.5% and 56.6% higher effect on the enzyme activity in cells from the bioreactor than the controls on day 9 and day 15, respectively.
[0069] For a bioreactor design to be successful, it is critical that it establishes a uniform environment for the cells it contains, and supports live and functioning cells. Various radial flow bioreactor designs have been used by several groups attempting to overcome this challenge (Iwahori et al. 2005; Miskon et al. 2007; Morsiani et al. 2001). From their results, radial flow design shows its advantages. Recent advances in the development of hepatocyte culture techniques, such as ECM enhancement techniques, micropatterning techniques, cell spray techniques, etc., provide possibilities to enhance hepatocellular functional performance by co-culturing the parenchyma and non-parenchyma cells. This symmetrically radial flow bioreactor was designed with great flexibility. The results of dye dispersion tests confirm that uniform flow is established within the bioreactor. On the other hand, by using Hypoxyprobe, no severe hypoxia was detected in the hepatocytes within the bioreactor. In evaluating hepatocyte performance within the cartridges of the bioreactor, the cells were found to maintain cell patterns similar to that of the sandwich cultures traditionally used to mimic cells in vivo. The cells in the cartridge were also able to achieve higher performance (i.e. ammonia clearance and albumin secretion) output for 2 weeks or more—again compared to the sandwich cultures as controls. Evaluations of the hepatocytes' ability to produce liver specific enzymes when housed within the bioreactor also indicate favorable results, the inducibility of EROD activity in hepatocytes maintained within the bioreactor is 30% higher than the sandwich culture in the plastic culture plates. These results demonstrate that hepatocytes perform well within the bioreactor. This is consistent with design expectations, since its cartridge design and dynamic flow enable the cells to access nutrients from two sides of the monolayer of cells. The nutrient transport barrier to the cells has been minimized to be less than 80 μm (including 30 μm of membrane thickness). This feature of enabling multi-directional mass transport is also achieved in the natural organ, in vivo. Furthermore the bioreactor establishes a uniform microenvironment for the cells it supports. This is important since the cells of the current study were isolated from an animal source (rather than a genetically engineered cell line). As such, the favorable microenvironment encourages the cells to quickly adjust to, and perform within, this novel in vitro system. As such, the results indicate that the novel bioreactor with a symmetric design is a successful system for maintaining large numbers of live and functioning cells for use in biomedical applications.
[0070] Again, it should be noted that, although the bioreactor assembly of the present invention is described herein largely in terms of liver support applications, its broader applicability is not so limited, as those of ordinary skill in the field will readily understand and appreciate. Many applications that are currently known and that have yet to be developed are contemplated by the present invention. At present, bioreactors are used in bioartificial organs, organ and tissue simulation, drug discovery and testing, cell/tissue manufacturing, antibody production, and, in general, the study and use of biochemical reactions (including those involving organisms, substances derived from or affecting organisms, cellular structures, etc.), as examples. Quite simply, the bioreactor assembly of the present invention may be used in any application that a bioreactor of any type is suitable for.
[0071] Although the present invention has been illustrated and described herein with reference to preferred embodiments and specific examples thereof, it will be readily apparent to those of ordinary skill in the field that other embodiments and examples may perform similar functions and/or achieve like results. All such equivalent embodiments and examples are within the spirit and scope of the present invention, are contemplated thereby, and are intended to be covered by the following claims.
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A bioreactor assembly, including: a housing internally defining a plurality of reaction chambers; a medium flow supply line associated with each of the plurality of reaction chambers, wherein the medium flow supply line associated with each of the plurality of reaction chambers is operable for delivering a medium flow to each of the plurality of reaction chambers; and one or more framed membrane cartridges selectively disposed within each of the plurality of reaction chambers, wherein each of the one or more framed membrane cartridges disposed within each of the plurality of reaction chambers is operable for holding a biochemically active material that is reacted when exposed to the medium flow.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority of U.S. Provisional Patent Application Ser. No. 60/778,170 filed Feb. 27, 2006, which is incorporated herein by reference
FIELD OF THE INVENTION
[0002] The present invention relates generally to a cardiac assist device, and in particular to a left ventricular assist device (“LVAD”) intended to work in series with a patient heart to augment tissue perfusion.
BACKGROUND OF THE INVENTION
[0003] For purposes of background, the disclosures of the following patent documents are hereby incorporated by reference in their entirety: U.S. Pat. Nos. 4,051,840; 4,630,597; 4,692,148; 4,733,652; 4,809,681; 5,169,379; 5,761,019; 5,833,619; 5,904,666; 6,042,532; 6,132,363; 6,471,633; 6,511,412; 6,735,532; and U.S. patent application Ser. Nos. 10/746,543; 10/770,269; 10/865,965; 11/178,969; and 60/709,323.
[0004] The scarcity of human hearts available for transplant, as well as the logistics necessary to undertake heart transplant surgery, make an implantable cardiac assist device the only viable option for many heart patients. An aortic blood pump, for example, can be permanently surgically implanted in the wall of the aorta to augment the pumping action of the heart
[0005] A known aortic blood pump includes a flexible bladder to be inflated and deflated in a predetermined synchronous pattern with respect to the diastole and systole of the patient to elevate aortic blood pressure immediately after aortic valve closure. Inflation and deflation of the bladder is accomplished by means of a supply tube connected to the bladder and to a percutaneous access device (“PAD”). The PAD is permanently surgically implanted in a patient's body to provide a through-the-skin coupling for connecting the supply tube to an extra-corporeal fluid pressure source. Electrical leads from electrodes implanted in the myocardium are likewise brought out through the skin by means of the PAD, The “R” wave of the electrocardiograph is used to control the fluid pressure source to inflate and deflate the inflatable chamber in a predetermined synchronous relationship with the heart action.
[0006] The aortic blood pump acts to assist or augment the function of the left ventricle and is typically restricted to use in patients who have some functioning myocardium. The aortic blood pump does not need to be operated all the time, and in fact, can be operated periodically on a scheduled on-time, off-time regimen, or on an as-needed basis. Typically, the patient can be at least temporarily independent of the device for periods of one to four hours or more, depending on their heart function and level of activity. The general structure of known aortic blood pumps is a semi-rigid concave shell, and a flexible membrane that is integrally bonded to the outer surface of the shell, forming an inflatable and deflatable chamber. A fabric layer is then bonded over the exterior surface of the shell that projects clear of the shell forming a suture flange. These blood pumps have been tested and demonstrated to last a few million cycles. None of the known blood pumps disclose or suggest that any modification can be made to the geometry of the shell and membrane to increase the durability of the pump, much less what such modification would be.
[0007] A known dynamic aortic patch has an elongate bladder having a semi-rigid shell with walls of uniform thickness and a relatively thicker peripheral edge and a flexible, relatively thin membrane defining an inflatable chamber. At least one passage extends through the shell defining an opening in the inner surface of the shell. The flexible membrane is continuously bonded to the shell adjacent the peripheral side edge to define the enclosed inflatable chamber in communication with the passage. The membrane may have a reduced waist portion, defining a membrane tension zone adjacent to the opening of the passage into the chamber to prevent occluding the opening to the pneumatic supply while deflating the chamber. An outer fabric layer can be bonded to the outer side of the shell of the aortic blood pump, and present a freely projecting peripheral edge to provide a suture flange for suturing the aortic blood pump in place within an incision in the aorta.
[0008] Known aortic blood pumps use an inflatable bladder and an envelope. The envelope is sutured to the aorta and then the bladder is placed inside the envelope. Although this design successfully augments the blood pumping capacity of the heart, it has two major disadvantages. First, fluid may accumulate inside the envelope, between the envelope and the inflatable bladder. This accumulation of static fluid within the body commonly leads to infection. Second, due to the geometry of the bladder, the volume of blood displaced by the device is limited, and has been determined to be insufficient.
[0009] Experience with patients has shown that it is relatively easy to construct a pump that will last a few million inflation-deflation cycles (on the order of weeks). However, it is very difficult to design, reproducibly manufacture, and implant a pump that will last for at least two years (on the order of a hundred million of inflation-deflation cycles, or more) without membrane failure.
[0010] The top surface of the pump's shell can be overlaid with a non-tissue adhesive substance, such as silicone, to prevent scar tissue from adhering to the back of the pump and to allow the pump to be explanted later. But clinical experience has shown that even this improved design may last less than the two-year target in a patient.
[0011] Known blood pumps have a suture ring placement that constrains the movement of the blood pump during each inflation-deflation cycle. In these designs, the suture ring is located closely adjacent to the shell bead, in a location outside of the periphery of the shell, and at approximately the same height (measured as the axial distance from the centerline of the aorta) as that of the bead. When the implantation wound heals, the suture line itself, as well as the scar tissue that grows into the suture line, constrain the movement of the shell during each inflation-deflation cycle. This occurrence results in effectively stiffening the shell near the region where it interacts with the membrane, thus forcing the membrane to absorb all of the stress during the inflation-deflation cycles.
[0012] The hose barb provides the connection between the internal conduit and the blood pump. Known blood pumps have hose barbs that are glued into place to the back of the shell of the blood pump. This design can be improved to increase the strength of the hose barb's attachment to the shell.
[0013] As seen in FIG. 11 , the shells of prior art blood pumps are relatively flat across their length, other than slightly turning downwards at the longitudinal ends, and have relatively thin walls of uniform thickness with slightly thicker peripheral edges. However, despite the simplified drawings of aorta in FIGS. 2, 3 , and 11 , the human aorta is not a straight circular cylinder. Rather, it has a complex three-dimensional shape, sometimes described as a “twisted question mark.” Accordingly, the known flat blood pumps are not well configured to fit to a typical human aorta, and there is a need in the art for a blood pump having a contour that generally matches the contour of a typical human aorta. Further, because of their general cylindrical configuration and relatively thin walls, the permanent deformation of these pumps during surgical implantation into the non-cylindrical aorta can affect their durability.
[0014] Thus, although the art discloses the basic concept of an “in-series” mechanical ventricle assist device blood pump), having a semi-rigid shell, and a flexible membrane, nothing in the art teaches or suggests how to construct a device that will be durable enough to survive inflation-deflation cycles for the number of years desired. To the contrary, clinical experience has shown that the known blood pumps generally last less than the two-year target. Thus, there remains a need in the art for a blood pump design providing increased durability.
SUMMARY OF THE INVENTION
[0015] A blood pump for placement in an incision in an aorta is provided that after placement contacts blood passing through the aorta. The pump inflates and deflates in order to provide left ventricular assistance. The pump has an elongated shell with a generally elliptical shape, an outer convex surface and an inner concave surface. A peripheral side edge located between the inner and outer surfaces terminates in a bead edge. A passage is provided through the shell to provide fluid communication between the outer surface and inner surface. A flexible airtight membrane has a membrane edge bonded to the outer shell surface adjacent to the bead edge to form an enclosed internal chamber in fluid communication with the passage. Preforming the membrane edge looped with a maximum linear span of curvature that is greater than a maximal transverse linear extent of the bead edge, membrane operational wear during inflation and deflation cycles is reduced in the region around the bead edge.
[0016] A process of forming a blood pump with a membrane preform is provided that includes placing an airtight membrane around a platen having a platen edge bead with a curvature of maximal transverse linear extent and a platen footprint substantially identical to a footprint of the blood pump shell. By heat setting the membrane, a looped membrane edge is formed as complementary to the curvature of the platen edge bead to yield a membrane preform. The membrane preform is secured to the outer surface of the shell having a bead edge of maximum linear extent less than the curvature of the looped membrane edge.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Preferred features of the present invention are disclosed in the accompanying drawings, wherein similar reference characters denote similar elements throughout the several views, and wherein:
[0018] FIG. 1 is a schematic perspective view of the major components of an LVAD system, as known in the art, implanted in a patient.
[0019] FIG. 2 is a schematic view of a longitudinal cross-sectional view of a blood pump in a deflated state.
[0020] FIG. 3 is a schematic view of a longitudinal cross-sectional view of a blood pump in an inflated state.
[0021] FIG. 4 is a schematic view of a transverse planar cross-sectional view along line 4 - 4 ′ of the pump shown in FIG. 2 in a deflated state.
[0022] FIG. 5 is a schematic view of a transverse planar cross-sectional view of a blood pump in a deflated state, in an embodiment with a shell having a hollow bead.
[0023] FIG. 6 is a schematic view of a transverse planar cross-sectional view of a blood pump in a deflated state, in an embodiment with the shell's wall region decreasing in thickess adjacent to the bead.
[0024] FIG. 7 is a schematic view of a transverse cross-sectional view of a blood pump in a deflated state, in an embodiment with an air pocket between the membrane and the bead.
[0025] FIG. 8 is a perspective view of a blood pump shell, including a hose barb.
[0026] FIG. 9 is a longitudinal cross-sectional view of a blood pump shell, including a hose barb.
[0027] FIG. 10 is a perspective view of a blood pump shell, including a hose barb and a suture ring.
[0028] FIG. 11 is a longitudinal cross-sectional view of a prior art blood pump shell.
[0029] FIG. 12 is a perspective view of a cylindrical blood pump shell, including a hose barb.
[0030] FIG. 13 is a longitudinal cross-sectional view of a cylindrical blood pump shell, including a hose barb.
[0031] FIG. 14 is a schematic view of a longitudinal cross-sectional view of a cylindrical blood pump with no vacuum/pressure applied to the membrane.
[0032] FIG. 15 is a schematic view of a transverse cross-sectional view of a cylindrical blood pump with no vacuum/pressure applied to the membrane.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0033] The present invention has utility as an implantable cardiac assist device. Through a modification of shell structure to include an enlarged bead edge relative to the shell wall the operational stability of the pump is enhanced.
[0034] For convenience, the same or equivalent elements in the various embodiments of the invention illustrated in the drawings have been identified with the same reference numerals. Further, in the description that follows, any reference to either orientation or direction is intended primarily for the convenience of description and is not intended in any way to limit the scope of the present invention thereto.
[0035] A basic known LVAD system, as shown in FIG. 1 , consists of the blood pump 2 , an inflatable bladder sutured into the wall of the aorta; an internal conduit 4 connecting the blood pump to the percutaneous access device (“PAD”); the PAD 6 , a through-the-skin port that permits power, electrical signals and fluid (typically air) to pass between the drive unit and blood pump; and the external drive unit 10 , a device powering and controlling the blood pump. The PAD 6 allows the implanted blood pump 2 to be operatively connected to or disconnected from the external drive unit 10 . To inflate the blood pump 2 , pressurized air is supplied from the drive unit compressor (not shown). The air flows from the compressor via an interconnect tube through a valve manifold in the drive unit 10 to an external drive line 8 running to the PAD 6 and then through the implanted internal conduit 4 to the blood pump 2 . Alternatively, an isolation chamber, separating the pressure (or vacuum) source from the air flowing to the pump, can be used to isolate the subcutaneous portion of the pneumatic circuit from the supercutaneous portion.
[0036] As seen in the longitudinal cross-sectional views of FIGS. 2 and 3 , the improved blood pump 20 of the present invention is implanted within the wall of the thoracic aorta 22 . The membrane 38 of the blood pump 20 is illustrated during deflation in FIG. 2 and during inflation in FIG. 3 . To implant the device, a surgeon makes a longitudinal incision through the wall of the aorta, usually downward from a location just below the subclavian artery, and the device is placed within the incision and sewn firmly in position by sutures (not shown) passing through a projecting suture ring flange 48 .
[0037] The outer side of the blood pump 20 , as implanted, is a relatively thick, semi-rigid shell 26 , which is molded from a suitable biocompatible material, such as urethane. As best seen in FIG. 8 , the shell 26 is of an elongate elliptical shape, with its upper or outer surface 33 being convex in both its longitudinal and transverse extents. The lower or inner surface 31 of the shell 26 is concave in its longitudinal and transverse extents, as seen in FIGS. 2-5 .
[0038] The shell 26 can be considered as having three regions: the spine region 57 , the wall region 55 , and the bead region 53 . The spine region 57 of the shell 26 is the relatively thick area of the shell that forms the housing 41 around the hose barb 40 , together with the area immediately surrounding the housing 41 . A passage 28 extends though the shell 26 to place the interior volume 30 of the blood pump 20 in fluid communication with the internal conduit 32 of the blood pump 20 .
[0039] The wall region 55 of the shell 26 is preferably thinner than the spine region 57 and extends out from the spine region 57 as seen in FIGS. 2 and 3 .
[0040] The bead region 53 of the shell has a bead 34 , and is thicker than the wall region 55 . The peripheral side edge of the shell 26 is smoothly rounded around its circumference, as best seen in FIG. 2 and 3 , and around its cross section, as best seen in FIGS. 2-4 , such that the bead 34 , which runs along the periphery of the shell 26 , is itself smoothly rounded throughout its entire extent, circumferentially around the elliptical shell, and also around its cross section. The shape of the bead 34 lessens local flexing stress, particularly when the membrane 38 is taut around the edge during the pump deflation cycle.
[0041] The membrane 38 is flexible, thin walled and bonded to the outer surface 33 of the shell 26 . The membrane 38 is preferably not adhered to the bead 34 or inner surface 31 of the shell 26 . Known solvation bonding techniques such as chlorinated solvent welding of polymers result in the membrane 38 and the shell 26 becoming what is in effect a unitary structure, but for purposes of explanation, the membrane 38 and the shell 26 are drawn in FIGS. 2 and 3 as separate components.
[0042] The outer surface 39 of the membrane 38 which, when implanted, interfaces with the blood in the aorta is preferably provided with fibrils, forming a textured surface similar to a flocking, to promote cellular adhesion in forming a pseudointima on the outer surface 39 of the membrane 38 .
[0043] A piece of sheet material 43 is attached to the outer surface 33 of the shell 26 . As indicated in FIGS. 2 and 3 , the periphery of the material 43 is preferably not attached to the outer surface 33 of the shell 26 and projects freely from the shell 26 to create a flange 48 . An additional material strip 49 , such as a pledget strip, is secured to the flange 48 by for example stitching, to provide a suture ring 44 for implanting the device in an incision in the aorta, as best shown in FIGS. 2, 3 and 10 . The strip 49 preferably has a fibrous surface allowing body tissues to migrate into, and mechanically interweaving with the strip 49 , to augment the sealing action initially established by the surgical implantation sutures (not shown) between the flange 48 of the suture ring 44 and the wall 50 of the aorta 22 . The sheet material 43 and strip 49 are made of various appropriate materials, such as polyester, which are commercially available and have been certified for use in implanted devices.
[0044] A number of modifications are optionally made to increase the durability of the blood pump by reducing the physical wear and stress on the membrane. The membrane failure of prior art designs is understood to have often been caused by microperforations due to membrane deformation, or “creasing,” during inflation-deflation cycles.
[0045] A blood pump is provided that has a contour that generally matches that of a typical human aorta. As seen in FIGS. 2, 3 , and 9 , the blood pump shell has a pronounced, continuous curve across its entire longitudinal extent. The interior curve of the shell as seen in FIG. 9 corresponds to the curvature of the aorta at the point of blood pump implantation. This curvature allows the pump to match the contour of a typical human aorta better than prior art pumps.
[0046] An inventive blood pump is provided with a large-diameter bead relative to the adjoining wall region of a pump shell to reduce the stress on the membrane during the cyclical operation of the pump. The large-diameter bead reduces stresses on the parts of the membrane coming in contact with the bead during the deflation cycle, while still being sufficiently flexible to be twisted and flexed during surgical implantation. Such properties are derived by varying the bead diameter relative to the shell thickness. As seen in the transverse planar cross-sectional view of the pump in FIG. 4A , the bead 34 has a membrane-contacting region 69 which contacts the membrane 38 when the pump is deflated. The portions of the pump 20 not in the plane of the transverse cut are not shown for visual clarity. As seen in FIG. 4A , the transverse wall region 65 of the shell 26 has a thickness T adjacent to the bead region 63 . A transverse spine region 67 is also defined. Preferably, the thickness of regions 55 - 65 , 53 - 63 and 57 - 67 are substantially equivalent. In order to further reduce localized stresses on the membrane 38 during the deflation cycle, the maximal linear extent D of the bead 34 at the membrane-contacting region 69 is preferably between about 110% to about 700% of T. In other words, ≠1.1 T≦D≦≈7 T. More preferably, D is between about 200% to about 600% of T. In other words, ≈2 T≦D≦6 T. Even more preferably, D is between about 400% to about 500% of T. In other words, ≈4 T≦D≦≈5 T. It is appreciated that while the bead 34 is depicted as spherical in cross section resulting in the maximal linear extent D corresponding to the diameter of the bead and that the bead is readily formed in a variety of shapes devoid of a sharp corner corresponding to a mathematical derivative singularity. An alternate bead shape in cross section is ellipsoidal, as shown in FIG. 4B .
[0047] In absolute dimensions, mathematical modeling/simulation and laboratory testing was conducted on a pump with the following approximate dimensions:
Overall length=130 mm Overall width=38 mm Wall thickness in wall region=2 mm
[0051] The testing indicated that on this pump, a bead diameter of approximately 7.0 mm advantageously reduced localized stress on the membrane, while still providing a shell with sufficient flexibility for purposes of implantation, and sufficient rigidity to hold its shape as required during implantation and use in vitro.
[0052] An inventive shell 70 is provided with a hollow bead 72 , as seen in the transverse cross-sectional view of FIG. 5 . The shell 70 is comparable to shell 26 with the exception of the hollow bead construction. This bead 72 has a tubular hollow region 74 running along the entire length of the bead 72 , considering the bead length running round the circumference of the side edge of the shell 70 . This hollow bead 72 reduces the rigidity of the shell 70 , at the interface with the membrane 38 , in comparison to the shell with a solid bead of the same diameter (as shown in FIG. 4 ). By reducing the rigidity of the shell 70 at the bead 72 , where the shell 70 interacts with the membrane 38 , the shell 70 deforms more during the inflation-deflation cycle (as compared to a shell with a solid bead), thereby allowing the shell 70 to share with the membrane 38 more of the stress caused by the cycling. It will be appreciated that if the shell is very rigid relative to the membrane (for example if it has a large-diameter solid bead), the membrane 38 is forced to absorb a greater share of the stress related to the cycling of the pump.
[0053] The thickness of the wall region 86 of the inventive shell 80 decreases from a maximum near the spine region 67 to a minimum near the bead region 63 , so that T 1 is greater than T 2 , as seen in the transverse cross-sectional view of FIG. 6 . The thinner wall region T 2 decreases rigidity of the shell 80 at the bead region 63 and consequently at the bead membrane contacting region 90 with the membrane 38 , in comparison to the shell 70 with a wall region of uniform thickness (as shown in FIG. 5 ). By reducing the rigidity of the shell 80 at the bead region 63 , where the shell 80 interacts with the membrane 38 , the shell 80 deforms more during the inflation-deflation cycle (as compared to a shell with a wall region of uniform thickness), thereby allowing the shell 80 to share more of the stress caused by the cycling with the membrane 38 .
[0054] In yet another embodiment, the membrane is modified, as compared to known pump membranes, to enhance the durability of the blood pump. In particular, the membrane 38 is preferably formed such that even without an applied pressure or vacuum (that is, without any significant pressure differential from one side of the membrane to the other), membrane shape generally matches that of the curved inner surface 31 of the shell 26 , as seen in FIG. 2 . This curved membrane is formed on a curved surface. This curved membrane experiences less creasing during the inflation-deflation cycles, as compared to flat membranes. Practical experience has shown that flat membranes crease at certain cusp points on the curved shell when they transition between inflated and deflated states. Analysis and testing indicate that the curved membrane reduces the magnitude and occurrence of this creasing problem.
[0055] In another embodiment, the blood pump is provided with an air pocket between the membrane and the bead, when the blood pump is in a deflated state, to reduce the stress on the membrane during the cyclical operation of the pump. As seen in the transverse cross-sectional view of the pump in FIG. 4A , the bead has a membrane-contacting region 69 which typically contacts the portion of the membrane when the pump is deflated. As shown in FIG. 7 , membrane 102 does not contact the bead 104 around the entire cross-sectional diameter of the bead 104 , due to air pockets 106 which form in proximity to the bead 104 during the deflation cycle. By heat setting the membrane on a large bead shell forming platen, and then bonding the resulting membrane 102 to shell 100 with a relatively smaller bead 104 , during deflation, the diameter D 2 of the air pocket created by the membrane 102 wrapping around the bead 104 is larger than the diameter D 1 of the bead 104 . In order to further reduce localized stresses on the membrane 102 during the deflation cycle, the diameter D 2 of the air pocket 106 created by the membrane 102 is always greater than the bead diameter D 1 . In other words, D 2 >D 1 . The local diameter D 1 of the bead 104 in this embodiment is preferably between about 110% to about 700% of the wall thickness T. In other words, ¢1.1 T≦D 1 ≦≈7 T. More preferably, D 1 is between about 110% to about 300% of T. In other words, ≈1.1 T≦D 1 ≦≈3 T. An air pocket 106 is formed in the gap between the membrane 102 and the bead 104 . The air pocket increases the radius of curvature of the membrane 102 near the bead 104 , thus reducing the strain on the membrane 102 during inflation-deflation cycles.
[0056] As best seen in FIGS. 12-15 , a shell 326 is relatively flat along a shell length with slightly downturned ends at the longitudinal termini, and a general cylindrical shape, with an upper or outer surface 339 that is convex in both longitudinal and transverse extents. The lower or inner surface 331 of the shell 326 is concave in its longitudinal and transverse extents.
[0057] The shell 326 can be considered as having three regions: the spine region 357 , the wall region 355 , and the bead region 353 . The spine region 357 of the shell 326 is the relatively thick area of the shell that forms the housing 341 around the hose barb 340 , together with the area immediately surrounding the housing 341 . A passage 328 extends though the shell 326 to place the interior volume 330 of the blood pump 320 in fluid communication with the conduit 332 of the blood pump 20 .
[0058] The wall region 355 of the shell 326 is preferably thinner than the spine region 357 and extends out from the spine region 357 as seen in FIG. 14 .
[0059] The bead region 353 of the shell 326 has a bead 334 , and is thicker than the wall region 355 . The bead 334 extends around the periphery of the shell 326 , as best seen in FIGS. 14 and 15 . The bead 334 is smoothly rounded throughout its entire extent, circumferentially around the cylindrical, elliptical shell 326 . The bead 334 minimizes local flexing stress, particularly when the membrane 338 is taut around the edge during the pump deflation cycle.
[0060] The membrane 338 is flexible, thin walled and is bonded to the outer surface 333 of the shell 326 . The membrane 338 is preferably not adhered to the bead 334 and inner surface 331 of the shell 326 . Known solvation bonding techniques such as chlorinated solvent welding of polymers result in the membrane 338 and the shell 326 becoming what is in effect a unitary structure, but for purposes of explanation, the membrane 338 and the shell 326 are drawn in FIGS. 14 and 15 as separate components.
[0061] The outer surface 339 of the membrane 338 which, when implanted, interfaces with the blood in the aorta is preferably provided with fibrils, forming a textured surface similar to a flocking, to promote cellular adhesion in forming a pseudointima on the outer surface 339 of the membrane 338 .
[0062] A piece of sheet material 343 is attached to the outer surface 333 of the shell 326 . As indicated in FIG. 14 , the periphery of the material 343 is preferably not attached to the outer surface 333 of the shell 326 and projects freely from the shell 326 to create a flange 348 . An additional material strip 349 , such as a pledget strip, is sewn to the flange 348 , to provide a suture ring 344 for implanting the device in an incision in the aorta, as best shown in FIG. 14 . The strip 349 preferably has a fibrous surface allowing body tissues to migrate into, and mechanically interweaving with the strip 349 , to augment the sealing action (initially established by surgical implantation sutures (not shown)) between the flange 348 of the suture ring 344 and the wall 50 of the aorta 22 . The sheet material 343 and strip 349 are made of various appropriate materials, such as polyester, which are commercially available and have been certified for use in implanted devices.
[0063] At least two modifications are optionally made to increase the durability of this blood pump by reducing the physical wear and stress on the membrane. The membrane failure of prior art designs is understood to have often been caused by microperforations due to membrane deformation, or “creasing,” during inflation-deflation cycles. This embodiment has a flat membrane 338 which lies flat and parallel to the plane described by the bead 334 of the shell 326 , when no pressure/vacuum is applied to the membrane 338 , as best seen in FIGS. 14 and 15 . The shell 326 has a general cylindrical shape with an interior surface area that is generally planar if the cylinder were “unrolled.” The surface area of the flat membrane 338 is complementary to the interior surface area of the cylindrical shell, and thus, the creasing at cusp points that is known to occur with a flat membrane and a curved shell at cusp is greatly reduced in this embodiment, resulting in increased membrane and pump durability. Further, this embodiment has improvements to decrease the occurrence of deformation during implantation. The cylindrical shell 326 includes a spine region, the relatively thicker region near the hose barb housing, which adds structural strength to the pump and decreases the likelihood of deformation during implantation; such deformations resulted in membrane creasing in prior art pumps.
[0064] As seen in FIGS. 2, 3 , 10 and 14 , the pump 26 or 326 is constructed so that the suture ring 44 and its flange 48 are located proximally closer to the spine region 57 of the shell 26 , as compared to prior art pumps. The suture ring 44 or 344 is located inward of the peripheral side edge 31 or 331 of the shell 26 or 326 viewed from above (as in FIG. 10 for shell 26 ): when the pump is viewed from the side, as in FIGS. 2 or 14 , the suture ring 44 or 344 is seen as being located above the outer surface 33 or 333 , as well as being entirely located between the longitudinal ends of the shell 26 or 326 .
[0065] In prior art designs, as seen in FIG. 11 , the flange 250 of the suture ring 214 is located adjacent to, and “outboard” of the bead 224 of the shell, resulting in the suture ring and the eventual incision scar interfering with the flexing of the shell, effectively increasing the rigidity of the shell. The improved suture ring placement of the present invention prevents the suture ring itself, as well as scar tissue forming on the suture ring, from interfering with the flexing of the shell during the inflation-deflation cycles, a design flaw found in prior art designs, as seen in FIG. 11 .
[0066] In order to facilitate surgical explantation of the device, the outer surface 56 or 356 of the sheet material 43 or 343 , other than at the flange 48 or 348 , is optionally overlaid with a substance to which tissue does not adhere. Biocompatible substances prohibiting cellular adhesion include fluoropolymers and silicone. The overlayer 99 prevents scar tissue from adhering to the sheet material 43 , so the blood pump can be explanted if desired. Without the overlayer 99 , as the implant incision healed, scar tissue would also adhere to the sheet material 43 covering the back of the blood pump complicating explantation of the pump 20 or 320 .
[0067] In certain embodiments, the conduit 32 of the pump is connected to a hose barb 40 or 340 , as seen in FIGS. 2, 3 and 14 . The hose barb 40 or 340 is preferably molded into the outer surface 33 or 333 of the shell 26 or 326 . The hose barb is of rigid biocompatible, nonferrous, MRI-compatible material, such as titanium. The conduit 32 or 332 connects to the hose barb 40 or 340 and runs to the PAD (not shown). The passage 42 or 342 through the hose barb 40 or 340 connects to the passage 28 or 326 and places the interior volume 30 or 330 in fluid communication with the conduit 32 or 332 .
[0068] While it is apparent that the illustrative embodiments of the invention herein disclosed fulfill the objectives stated above, it will be appreciated that numerous modifications and other embodiments may be devised by those skilled in the art. For example, it will be appreciated that features of the embodiments disclosed above can be used in various combinations and permutations. Therefore, it will be understood that the appended claims are intended to cover the forgoing—and all other—modifications and embodiments which come within the spirit and scope of the present invention.
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A blood pump for placement in an incision in an aorta is provided that after placement contacts blood passing through the aorta. The pump inflates and deflates in order to provide left ventricular assistance. The pump has an elongated shell with a generally elliptical shape, an outer convex surface and an inner concave surface. A peripheral side edge located between the inner and outer surfaces terminates in a bead edge. A passage is provided through the shell to provide fluid communication between the outer surface and inner surface. A flexible airtight membrane has a membrane edge bonded to the outer shell surface adjacent to the bead edge to form an enclosed internal chamber in fluid communication with the passage. Preforming the membrane edge looped with a maximum linear span of curvature that is greater than a maximal transverse linear extent of the bead edge, membrane operational wear during inflation and deflation cycles is reduced in the region around the bead edge. A process of forming a blood pump with a membrane preform is provided that includes placing an airtight membrane around a platen having a platen edge bead with a curvature of maximal transverse linear extent and a platen footprint substantially identical to a footprint of the blood pump shell. By heat setting the membrane, a looped membrane edge is formed as complementary to the curvature of the platen edge bead to yield a membrane preform. The membrane preform is secured to the outer surface of the shell having a bead edge of maximum linear extent less than the curvature of the looped membrane edge.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a control method of a centrifuge using a balancer, more particularly a control method that helps the rotor rotate more stably and thus improve the lifetime of the centrifuge by controlling the rotation of the rotor in such a way that the unbalance due to the weight of the samples is compensated accurately and stably when centrifugating the samples loaded in the rotor using the balancer containing balls, a liquid, or both balls and a liquid, thereby reducing the vibration due to the unbalance.
[0003] 2. Description of the Related Art
[0004] In general, by introducing the centrifugal force, instead of gravity, to particles in suspension or substances dissolved in a liquid medium, the sedimentation phenomenon can be accelerated and this process is called centrifugation.
[0005] The centrifuge that is used in such a centrifugation is a device employing the principle that the particles of high density contained in suspension tend to migrate to the edge by centrigual force while the particles of low density tend to gather toward the center, and its general configuration is illustrated in FIG. 1 .
[0006] As illustrated in FIGS. 1 a and 1 b, the general centrifuge has a cushioning member such as vibration-proof rubber or a damper installed to a supporting plate formed at the inner surface of the case, and a bracket or supporting plate installed on the top of said cushioning member. It is a general configuration to install a motor to said bracket or supporting plate, and mount a rotor to the rotating shaft projected from said motor.
[0007] This centrifuge uses different types of rotor, depending on its use; a swing-out rotor type rotating perpendicularly to the rotating shaft of the motor and a fixed angle type with cavities rotating at a predetermined angle provided therein.
[0008] As the motor rotates at a high speed, exerting a strong centrifugal force to the samples in the bottles or the test tubes which arc disposed inside a horizontal or fixed angle rotor, the centrifuge separates the substances contained in the samples by the difference in the centrifugal forces due to the differences in density. A strong centrifugal force must be exerted to the samples for the separation of the substances in the samples, and in order to apply a strong centrifugal force to the samples, generally the rotor must rotate at a high speed and vibration must not be generated particularly during the high-speed rotation of the rotor.
[0009] However, in the process of the high-speed rotation of a centrifuge, vibration is generated by a combination of different causes; deflection motion of the rotating shaft of the motor, whirling motion due to the unbalance of the rotor weight, and other external factors. Among these causes of vibration, the most common cause is the whirling motion due to the unbalance of the rotor weight.
[0010] Therefore, for the centrifuge without a balancer, to remove the unbalance that occurs due to the differences in the number or weight of the samples disposed in the rotor, the operator should separately measure the weights of the samples before the operation of centrifugation and remove the differences in weight between the samples before rotating the rotor, which causes an inconvenience in operation.
[0011] If the unbalance of weight between the samples occurs, the vibration is generated in the process of centrifugation, causing the problems that the substances in the samples are not separated or even if they had been separated, the separated substances could be remixed with vibration. Furthermore, noise is generated in the process of centrifugation by said vibration.
[0012] The centrifuge has a problem in that the action of force and moment due to the unbalance of weight between the samples could cause an excessive vibration in the process of centrifugation, causing a failure of the centrifuge itself. In order to solve those problems of noise and vibration generated in the process of centrifugation, a cushioning member such as a damper or rubber was installed, but had a shortcoming that it did not sufficiently absorb the noise and vibration. Therefore, a centrifuge using a balancer containing balls was suggested in order to solve the problems of noise and vibration caused by the unbalance of weight between the samples.
[0013] The ball balancer illustrated in FIGS. 3 a and 3 b is configured to have compensation material installed inside the case ( 130 ) which is formed with a balancing space of an annular shape, wherein a shaft hole ( 105 ) through which a rotating shaft of the motor is fixedly coupled is formed in the center of the balancer.
[0014] The ball balancer configured as above is provided with balls to an extent of occupying a portion of the balancing space ( 150 ) which is formed inside the case ( 130 ), and has an advantage that when the rotational speed of the motor (not shown) exceeds the resonant speed, the balls move to an opposite direction to the weight unbalance position, thereby balancing the rotor (not shown) and stabilizing the rotation.
[0015] However, it has a drawback that often times an accurate balancing could not be achieved due to various factors such as the vibration characteristics of the system, the initial location of balls, the internal friction of the balancer, etc., and in this ease, the high-speed rotation of the rotor could cause strong vibration and noise, resulting in the safety-related accidents.
SUMMARY OF THE INVENTION
[0016] It is an object of the present invention to provide a control for a centrifuge using a balancer in order to solve the problem of excessive vibration that can be generated when the compensation for the unbalance is not achieved accurately or the compensation material is moved irregularly due to the system damage during the high speed rotation of the rotor or by the action of external forces. In other words, the object of the present invention is to smoothly control the balancer containing balls, a liquid, or both balls and a liquid which provides an automatic balancing even in case the operator did not accurately adjust the weights of the samples before loading.
[0017] The above and other objects can be accomplished by the provision of a centrifuge using a balancer, wherein the control comprises a step to accelerate beyond the resonant speed where the balancing is achieved, a step to measure the vibrational acceleration, a step to judge whether or not the acceleration is possible, and a step to decelerate below the resonant speed, in addition to the basic control that accelerates to the target rotational speed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The above and other objects, features and advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:
[0019] FIG. 1 a is an exemplary embodiment of a conventional centrifuge (a fixed angle rotor type) and FIG. 1 b is an exemplary embodiment of a conventional centrifuge (a swing-out rotor type).
[0020] FIGS. 2 a through 2 d are sectional views illustrating exemplary embodiments of a centrifuge using a balancer according to the present invention.
[0021] FIG. 3 a is a sectional view illustrating an exemplary embodiment of a balancer according to the present invention, and FIG. 3 b is a perspective view of FIG. 3 a.
[0022] FIG. 4 is a graph illustrating a theoretical location of compensation material for the resonant speed.
[0023] FIG. 5 is a flowchart for the control method of a centrifuge using a balancer in accordance with the present invention.
[0024] FIG. 6 is a graph illustrating an example of an allowed vibration range and various vibrational characteristic curves for the rotational speed.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0025] Hereinafter, the preferred embodiment of the present invention will be explained in detail with reference to the accompanying drawings.
[0026] As illustrated, a centrifuge using a balancer according to the present invention comprises a motor ( 50 ), a rotating shaft ( 40 ) of the motor projected from said motor, a rotor ( 200 , 200 a ), and a balancer ( 100 ).
[0027] The following is the detailed description with reference to FIGS. 2 a through 2 d.
[0028] The centrifuge of the present invention comprises a supporting plate ( 15 ) formed at an inner surface of the outer case ( 10 ) and a rotor ( 200 , 200 a ) that is mounted onto the rotating shaft of the motor projected from the motor ( 50 ) that is mounted to said supporting plate ( 15 ).
[0029] It is desirable that said motor ( 50 ) is supported by a cushioning member ( 30 ) such as a damper or rubber. Said cushioning member ( 30 ) plays a role to absorb a portion of the noise and vibration generated from the centrifuge due the high-speed rotation of said motor ( 50 ).
[0030] The rotating shaft ( 40 ) projected from said motor ( 50 ) is coupled with a fixed angle rotor ( 200 ) which is formed with a plurality of chambers ( 60 ). Those chambers ( 60 ) formed in said fixed angle rotor ( 200 ) are formed in such a way that the lower end (not shown) of said chamber is slanted outwardly from the center of said rotating shaft ( 40 ) of the motor, as illustrated in FIGS. 2 a and 2 b.
[0031] Furthermore, in another embodiment, said centrifuge is configured to use a swing-out rotor ( 200 a ) as illustrated in FIGS. 2 c and 2 d , wherein said swing-out rotor ( 200 a ) rotates perpendicularly to said rotating shaft ( 40 ) of the motor. Said swing-out rotor ( 200 a ) is configured in such a way that the buckets (not shown) in which the samples are loaded are hung by means of rings (not shown). In the centrifuge configured as above, a balancer ( 100 ) that is going to be described afterward is installed somewhere in said rotating shaft ( 40 ) of the motor or said rotor ( 200 , 200 a ). Hereinafter, said balancer ( 100 ) will be described in detail with reference to FIGS. 3 a and 3 b.
[0032] As illustrated, the balancer ( 100 ) in accordance with the present invention comprises a cover ( 120 ) and a main body ( 130 ), wherein these two members are coupled to each other. Said cover ( 120 ) and said main body ( 130 ) can be coupled to each other by means of the interengaging grooves and projections (not shown) formed on the corresponding locations or screws (not shown). The coupling methods between these two members are well known and the detailed description thereof will be omitted.
[0033] In the center of said balancer ( 100 ), a connecting part ( 110 ) having a through-hole ( 105 ) to which a portion of said rotating shaft ( 40 ) of the motor or said rotor ( 200 , 200 a ) is connected is provided.
[0034] Inside said balancer ( 100 ), a balancing space ( 150 ) of an annular shape is provided and compensation material is kept contained therein for balancing weight unbalance between the samples in the process of centrifugation. Said compensation material can be one of many different configurations such as solid, liquid, or a mixture of solid and liquid, and is not limited to any particular configuration. The amount of the compensation material stored in said balancing space ( 150 ) can be adjusted to an appropriate level depending on the operating conditions of centrifugation.
[0035] When the rotational speed of the rotor is lower than the resonant speed, as illustrated in FIG. 4 , said compensation material of the balancer is located on the same side as the unbalanced mass, thereby further increasing the overall unbalance and causing stronger vibration. When the rotational speed of the rotor exceeds the resonant speed, the compensation material moves to the opposite direction of the unbalance, achieving the balance and thus reducing the vibration. In general, it occurs on occasion that the ideal balancing cannot be achieved when the initial location for the unbalance of the compensation material contained in the balancer happens to be in the region where little movement of the compensation material occurs. Therefore, in case that an accurate balancing has not been achieved, as illustrated in FIG. 5 , the balancing has to be executed again after the speed of the rotor has been reduced so that the accurate balancing can be achieved. Because the judgement on the balancing accuracy used in the process as above is executed during the low-speed rotation of the rotor and used as a basis to determine whether or not the acceleration is possible, the time for overall centrifugation can be saved, making the operation efficient.
[0036] It is efficient to setup a standard for judgement on the balancing accuracy based on the allowable vibrational acceleration or the unbalance amount according to the preset rotational speed. In other words, there exist the differences in the maximum allowable vibration value according to the preset rotational speed, and if the allowed vibrational acceleration is set too low, the number of attempts for balancing until the accurate balancing is achieved increases while if the allowed vibrational acceleration is set too high, excessive vibration is generated in the system, shortening the product life or causing the safety-related accidents.
[0037] Even in case that the rotor accelerates to the preset rotational speed or maintain a constant speed once it reaches the preset rotational speed after going through said judgement process on the balancing accuracy, it occurs on occasion that the vibration becomes greater because the balancing becomes broken due to various factors such as the irregular movement of the compensation material inside the balancer, the damage of the system, or the action of external forces.
[0038] Therefore, the damage to the equipment and the safety-related accidents can be prevented by setting the allowed vibration limit corresponding to each rotational speed of the rotor and stopping the rotation of the rotor in case that the allowable vibrational acceleration for the corresponding rotational speed is greater than the measured vibrational acceleration.
[0039] FIG. 6 illustrates the allowed vibration limit ( 300 ) and the examples of various types of vibrational characteristic curves ( 310 , 320 , 330 ) for an arbitrarily set rotational speed ( 350 ). In case the preset rotational speed ( 350 ) represented by a solid line is changed to a new preset value, it is desirable to apply an allowed vibration limit that is appropriate for the newly preset speed. The characteristic curve ( 310 ) represented by a dotted line where the allowed vibration limit is not exceeded at all during the acceleration from the low speed to the preset speed is the case where the acceleration to the preset speed is possible. For the characteristic curve ( 320 ) represented by a dot-dash line where the vibration level is higher than the allowed vibration limit already from the low speed, the acceleration must be stopped and it is safe to execute the balancing again after reducing the speed. The characteristic curve ( 330 ) represented by a dot-dot-dash line which intersects with the allowed vibration limit curve shows that the allowed vibration limit is exceeded from the intersecting point ( 340 ) through the preset speed. In other words, for such a characteristic ( 330 ), the speed should be reduced at the point where two curves intersect before executing the balancing again. Or another control to be considered could be that before reducing the speed, the vibration characteristic is a little further observed for a certain period of time after the intersecting point appears.
[0040] The allowed vibration according to said rotational speed becomes different depending on the vibration characteristic of the system, and this vibration characteristic is different for different rotor type in use. In general, the centrifuge uses a method that the user enters into the system the type of rotor mounted, and the preset rotational speed entered according to the rotor type entered and the maximum allowed vibrational acceleration for each rotational speed are used as the standard for judgement on the excessive vibration. In case that said entered rotor is different from the type of the rotor actually installed, there occurs a problem that the system recognizes the incorrect information of the allowed vibrational acceleration. Therefore, it is needed to identify the type of the rotor actually mounted, and by utilizing the fact that different type of rotor has different resonant speed, measuring the vibrational acceleration during the acceleration of the rotor and then comparing the resonant speeds can identify the type of the rotor installed. In case that the information of the rotor entered is different from the one of the rotor in actual use, the operator is notified of it and the rotation should be stopped in order to confirm the type of the rotor and correct it for the stable use of the centrifuge.
[0041] The centrifuge using said balancer has the maximum compensable unbalance determined and in case that the samples are loaded with the unbalance that exceeds the compensable mass, no balancing can be achieved. Therefore, the vibrational acceleration becomes greater in case that the unbalance exceeds the compensable limit than that the unbalance is smaller that the compensable limit, and if it is possible to sense it in advance, the number of unnecessary attempts of balancing can be reduced, saving the time needed for centrifugation. In order to accomplish said object, if the vibration level is greater than the one for the case that the amount of the unbalance loaded is same as the allowed compensation limit, it is possible that the excess of the allowed compensable mass is notified and the centrifugational operation is stopped.
[0042] The accurate balancing can be obtained by controlling the acceleration of the rotor of the centrifuge using said balancer. As illustrated in FIG. 4 , the balancing is achieved as the compensation material moves to the opposite direction of the unbalance by the vibration and phase change generated when the rotational speed of the rotor passes the resonance region. Therefore, in case that the rotational speed of the rotor passes the resonance region quickly, the compensation material cannot move to the opposite direction of the unbalance sufficiently. In this case, by reducing the rotational acceleration of the rotor or maintaining a constant speed for a certain period of time in the resonance region, the compensation material moves to the opposite direction of the unbalance accurately.
[0043] (1) The noise and damage to the equipment caused by the unbalance and high-speed rotation of the rotor can be prevented in advance because it is decided before the high-speed rotation of the rotor whether or not the acceleration is possible, based on the judgement on the balancing accuracy.
[0044] (2) The probability of the balancing failure can he lowered and the centrifugation time can be saved because the target rotational speed and the unbalance amount are compared to determine whether or not the acceleration of the rotor is possible.
[0045] (3) In case that the maximum compensable unbalance is exceeded, a prior warning is provided during the low speed interval and the operations is stopped, reducing the number of unnecessary attempts for balancing and thus saving the centrifugation time.
[0046] (4) The excessive vibration that could be generated during the high-speed rotation of the rotor is promptly interpreted and the rotor is stopped, preventing the noise that could be generated due to the excessive vibration and the damage to the equipment.
[0047] (5) Because the type of rotor is checked in advance during the low-speed interval and compared with the entered setting of rotor type to identify any error in setting, the control error caused by the incorrect setting is prevented in advance, saving the centrifugation time and preventing the safety-related accidents.
[0048] (6) Because the rotating speed of rotor is decelerated or maintained a constant speed for a certain period of time during the resonance interval where the vibration is strong, an excellent effect of balancing is achieved.
[0049] Although the present invention herein has been described in the above with reference to the preferred embodiment, it will be apparent to those skilled in the art that various changes and modification may be made to the above described embodiments, without departing from the scope and spirit of the present invention as disclosed in the accompanying claims.
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The present invention relates to a control method of a centrifuge using balancer wherein a balancer containing balls, a liquid, or both balls and a liquid are provided, thereby helping the rotor rotate more stably.
More particularly, the centrifuge comprises a motor, a rotational shaft of the motor projected from said motor, a rotor, a main body, and a balancer which contains compensation material in a balancing space formed by a cover that is coupled to said main body, wherein the balancing for the unbalance due to the loaded samples is executed more accurately and stably.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to crutches and more specifically to leg support crutches designed to permit ambulatory movement by a patient recuperating from an injured foot or lower leg.
2. Description of Related Art
A patient after injuring a foot or lower leg, commonly uses a pair of crutches to support himself or herself when recuperating. The crutches aid the patient when walking by supporting a portion of the patient's body weight.
Each crutch conventionally includes a pair of legs attached to an upper cross bar or crutch head. The legs depend downwardly from the crutch head towards a lower end. The crutch also includes a hand grip attached to the legs and positioned between the crutch head and the lower end, about two-thirds up the length of the crutch from the lower end.
The patient uses the crutch by placing the crutch head under his or her arm in the axilla (i.e., armpit) and grasping the hand grip. The patient generally supports his or her weight by the combination of grasping the hand grip and resting on the crutch head. Unfortunately, extended use of conventional crutches generally results in some discomfort to the axillae and lateral sides of the rib cage, and may result in nerve injury.
To overcome the disadvantage of conventional crutches, there have been efforts to develop a single support crutch that more directly supports the user's leg without the need to grip the crutch with one's hands or bear upon the crutch at or about the axillae and rib cage. U.S. Pat. Nos. 5,575,299, 5,300,595 and 5,178,595 disclose examples of such prior single support crutches. In essence, each of these single support crutches removes stress from the user's axillae and rib cage and transfers that stress to the user's knee and thigh. None of the single support crutches to date, however, have been able (i) to satisfactorily minimize the stresses on a user's knee, (ii) to more evenly distribute the forces that bear upon the user's thigh during use, and (iii) to provide the stability required for full ambulatory movement of the user.
SUMMARY OF THE INVENTION
A need therefore exists for a method and a device for minimizing the stress upon the knee and thigh while permitting a patient as full ambulatory movement as possible during recuperation.
One aspect of the present invention thus involves an improved leg support crutch that permits ambulatory movement of a user recuperating from a lower leg or foot injury. The leg support crutch supports the user's upper body and injured lower leg in a manner that transfers the user's body weight through the user's thigh and knee directly to the leg support crutch so as to bypass weight transfer through the user's injured lower leg or foot. The leg support crutch comprises a unitary leg cradle, a support strut connected to the leg cradle, an interengaging structure for releasably connecting the support strut to the leg cradle at a plurality of locations, and a plurality of fasteners to secure the user's leg within the leg cradle.
The leg cradle desirably has a generally L-shaped configuration defined by a first portion contoured to loosely conform to the shape of a user's thigh and a second portion positioned generally normal to the first portion and integral therewith. The second portion is contoured to loosely conform to the shape of a user's lower leg. The junction of the first and second portion forms a curvilinear profile conforming loosely to the user's knee.
The first and second portions include corresponding vertical and longitudinal axes that intersect at a generally right angle. The axis of each portion is defined centrally between the corresponding sides of the portion and is distanced from a front or lower wall of the corresponding first or section portion. For instance, the vertical axis of the first portion desirably is distanced from the front wall by a sufficient distance to generally align the vertical axis with the user's femur when in use.
The first portion is sufficiently long so as to secure the first portion high-up on the user's thigh. This length of the first portion generally inhibits movement of the first portion relative to the user's thigh without unduly binding the thigh and overly constricting the arteries and veins in the leg (e.g., the popliteal artery).
The cradle is further defined by integral gussets. The gussets join together and reinforce the first and second portions so as to transfer forces (e.g., weight) from the second portion to the first portion when the second portion is supporting the user's lower leg. Each gusset extends between the first and second portions and the gussets are positioned to straddle a portion of the user's lower leg and thigh when in use.
The support strut detachably connects to the cradle proximal to the intersection of the first and second portions so as to be generally parallel with the longitudinal axis of the first portion when the support strut is attached to the cradle. The strut is adjustable in length to permit use of the prosthetic device by users of different leg lengths.
The interconnecting structure detachably connects the support strut to the leg cradle at a plurality of locations. The position of the strut thus may be adjusted to position the strut to lie generally collinear with the user's femur to transfer of the user's body weight to the strut. The strut thereby simulates the balance and support normally provided by the user's lower leg and foot.
There are a plurality of adjustable fasteners positioned on each of the first and second portions of the leg cradle to hold the user's thigh and lower leg tightly in the cradle. The fasteners are positioned to maximize the stability of the prosthetic device while in use and to minimize constriction of the user's leg. A first fastener of the plurality is positioned at an upper end of the first portion to maximize the force securing the first portion to the user's thigh (i.e., to maximize the moment arm created by the first portion with respect to an axis of rotation through the user's knee). This force resists the tendency of the strut, when in motion, to pull the first portion away from the user's thigh, thereby inhibiting the cradle from rotating about the user's knee. This arrangement also minimizes the reactive forces experienced by the user's thigh in resisting such rotation.
A second fastener is also arranged on the first portion near a lower end of the first portion but sufficiently spaced therefrom to permit attachment of the cradle to the user's leg above the popliteal fossa. This arrangement minimizes constriction of the popliteal artery caused by this second fastener when in use.
The plurality of fasteners further includes at least two fasteners--a third and a fourth fastener--positioned on the second portion. These fasteners permit attachment of the second portion to the lower leg of the user. The third fastener is desirably positioned proximal to the middle of the user's calf muscle when attached, and the fourth fastener is desirably positioned between the bottom of the user's calf and the user's ankle.
Further aspects, features, and advantages of the present invention will become apparent from the detailed description of the preferred embodiment which follows.
BRIEF DESCRIPTION OF THE DRAWINGS
The above-noted and other features of the invention will now be described with reference to the drawings of a preferred embodiment which is intended to illustrate and not to limit the invention, and in which:
FIG. 1 illustrates a side elevational view of the leg support crutch configured in accordance with a preferred embodiment of the present invention, as applied to a user's thigh and lower leg;
FIG. 2 illustrates a perspective view of the leg support crutch of FIG. 1, from a rear-left side;
FIG. 3 illustrates a perspective view of the leg support crutch of FIG. 1, from a front-right side;
FIG. 4 illustrates a side elevational view of the leg support crutch of FIG. 1 with the user in a seated position and with a support strut disconnected;
FIG. 5 illustrates an exploded perspective view of the leg support crutch of FIG. 1 from the rear-left side, showing the discrete components employed in the preferred embodiment;
FIG. 6A illustrates an exploded perspective view of an embodiment of the interengaging structure that connects the strut to the underside of the leg cradle, with the strut arranged in a first position; and
FIG. 6B illustrates an exploded perspective view of the strut, cradle and interengaging structure with the strut arranged in a second position.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
With reference to FIGS. 1 through 3, a preferred embodiment of the leg support crutch 10 is shown as applied to a user (shown in phantom). The leg support crutch 10 is defined by a leg cradle 12, preferably molded in unitary construction, and a detachable support strut 14. An interengaging structure 16 connects the support strut 14 to the leg cradle 12 in a manner that permits quick detachment and adjustment relative to the cradle, as well as connects the support strut 14 to the cradle 12 in at least two different positions relative to a vertical axis a of the cradle 12, as described below.
The leg cradle 12 supports the thigh, knee and lower leg of a user recuperating from a lower leg or foot injury in a manner that comfortably transfers the weight of the user through the cradle 12 to the support strut 14. This is done in a manner that also simulates the balance and support normally provided by the user's lower leg and foot, thus enhancing recuperation while the user remains ambulatory.
The leg cradle 12 includes a desirably plurality of fasteners--four fasteners 20, 22, 24 and 26 in the illustrated embodiment--to securely attach the user's thigh and lower leg to the leg cradle while in use. Each fastener is strategically positioned along the cradle 12 to firmly hold the user's leg within the cradle 12 without unduly constricting user's leg.
Leg Cradle
As seen in FIGS. 1 through 3, the leg cradle 12 is principally defined by a first portion 30, which bears against the user's thigh, and a second portion 32, which carries the user's lower leg. The first and second portions 30, 32 are contoured to loosely conform to the shape of a user's thigh and lower leg, respectively. Thus, both the first and second portions 30, 32 generally have an arcuate channel that wraps about a anterior portion of the user's leg. The channel generally has a U-shaped cross-sectional shape formed between side walls and an interconnecting wall, i.e. a front wall on the first portion 30 and a bottom wall on the second portion 32.
The first and second portions 30, 32 are formed in a generally L-shaped configuration. The intersection 34 of the first and second portions 30, 32 is curvilinear in profile to loosely conform to the user's knee. As shown more clearly in FIG. 2, the contour of the entire leg cradle 12 closely resembles the contour of the front and sides portions of a user's thigh, knee and lower leg, but not so closely, when in use, so as to uncomfortably constrict the user's leg. An unobstructed view of the leg cradle 12 is also shown in FIG. 5.
As seen in FIG. 1, the first portion 30 is formed about a generally vertical axis "a" that intersects, in generally normal relationship, with a generally longitudinal axis "b." The second portion 32 is arranged to lie generally parallel to this longitudinal axis "b". In one embodiment, the angle between the longitudinal axes "a", "b" is acute by approximately 5° from normal so that, when the user is standing upright in the leg support crutch 10, the user's lower leg is supported by the second portion 32 in a slightly elevated manner, with the foot slightly higher than the knee. That is, the angle between the first and second portions is about 85°. This elevation of the lower leg enhances fluid draining away from the user's foot and ankle, as well as and blood circulation, during recuperation. It should be recognized that, depending upon the nature of the injury to the lower leg or foot, the incident angle between the first and second portions 30, 32 may depart from normal by varying degrees without losing the benefits of the present leg support crutch.
The length of the first portion 30 desirably equals approximately two-thirds to three-quarters of the length of the user's thigh, such that the first portion 30 extends substantially up the user's thigh. This length serves the advantage of extending the moment arm created by the first portion 30, as discussed in detail below, which serves to minimize the forces experienced by the user's thigh during use. The extended length of the first portion 30 also serves the advantage of increasing the area across which forces are spread about the user's thigh, further minimizing the forces experienced by the thigh.
The second portion 32 desirably has a length sufficient to support generally the entire length of the user's lower leg. In the illustrated embodiment, the second portion 32 extends to a point below the user's calf and just above the user's ankle to adequately support the user's foot. The outer end of the second portion 32 (i.e., the end near the user's ankle), however, does not extend so far as to cause discomfort to the user's dorsal foot and ankle. The length of the second portion is at least as long as the length of the first portion.
With reference now to FIGS. 1 and 5, a pair of integral gussets 36 extend between the first portion 30 and the second portion 32. In the illustrated embodiment, the gussets 36 are integrally formed with the sides of the first and second portions 30, 32 and are arranged to straddle the side of the user's thigh and lower leg, when worn. The gussets 36 reinforce the leg cradle 12 and transfer the weight of the second portion's outer end (which supports the user's foot and lower leg) to the first portion 30 (thereby functioning as trusses). The gussets 36 also advantageously eliminate the direct transfer of rotational forces from the weight of the user's lower leg to the strut where shear forces would otherwise be generated on the strut.
The leg cradle 12 preferably has curled edges 38 throughout, wherein the edges curl away from the user's body, as shown in FIGS. 1 through 3. This feature minimizes the risk of abrasive contact between the user and the edge of the cradle while in use. The edges also serve the added benefit of reinforcing the cradle 12 about the gussets 36 as they transfer weight from the second portion 32 to the first portion 30.
Unlike other leg support crutches that consist of multiple bands mechanically interlinked to simulate a cradle, the preferred embodiment of the leg cradle 12 is made of unitary construction and conforms to the contour of the user's thigh and leg. This construction more evenly distributes the forces borne the user's thigh during use, as discussed further below. In the preferred embodiment, the leg cradle 12 is made of molded fiberglass that permits construction of a highly contoured cradle designed to comfortably support a user's thigh and lower leg by virtually encasing the front and side portions of the thigh and lower leg. This construction also permits highly customized leg support crutches. Other similarly sturdy and moldable materials of course can also be used, such as for example plastic (e.g., PVC or ABS) and the like.
The cradle 12 also desirably includes an insert pad 40 to provide further comfort and secure fit. In the illustrated embodiment, the insert pad 40 is made of textured neoprene; however, other suitable material (e.g., nylon-wrapped foams) can also be used. As shown in FIG. 5, the insert pad 40, has a contour conforming generally to the inner surface of the cradle 12 that permits a slip fit of the insert pad 40 into the interior of the cradle 12. The edges of the insert pad 40 desirably extend beyond the curled edges 38 of the cradle 12 to further protect the user against potential abrasive contact with the rigid cradle during use.
Support Strut
FIGS. 1 and 5 also illustrate the support strut 14 which includes a rigid longitudinal portion. The rigid longitudinal portion in the illustrated embodiment comprises a telescoping support 44. The telescoping support 44 includes two concentric tubes 46, 48 in which an upper end of the smaller diameter tube 46 engages the interengaging structure 16 (which is described below). Quick-release engagement of the support strut 14 with the leg cradle is permitted by providing a quick-release fastener 50 positioned at the distal end of the smaller diameter tube 46. The quick-release fastener 50 mates with a corresponding feature in the interengaging structure 16.
The smaller and larger diameter tubes 46, 48 are movable with respect to each other in a telescoping fashion to adjust the overall length of the telescoping support 44. A second quick-release fastener 52 is used to securely fasten these tubes together once the length of the support 44 has been adjusted to a desired length.
In the illustrated embodiment, the quick-release fasteners each comprise a detent mechanism; however, other type of known quick-release fasteners can also be used. The quick-release fastener 52 at the lower end of the support 44 includes a pair of spring-biased detent balls positioned at opposite ends of the smaller diameter tube 46. The larger diameter tube 48 includes a plurality of holes 54 aligned in series to receive the second quick-release fastener 52. The second quick-release fastener 52 itself may be adjustably positioned within one of a series of holes 58 in the smaller diameter tube 46. The upper quick-release fastener 50 includes a similar structure and cooperates with a pair of holes formed in the corresponding structure of the interengaging structure, as described below.
At a lower end of the support strut 14, the larger diameter tube 48 supports a non-skid cap 60 preferably made of rubber or other suitable material to minimize slippage of the support strut 14 with the ground during use. The non-skid cap 60 may be of various configurations and preferably comprises a generally form fitting sleeve closed at the distal end to increase the area of engagement between the support strut 14 and the ground. Other configurations are contemplated, including a form fitting sleeve that includes a plurality of projecting feet each of which engage the ground in a non-skid manner.
Interconnecting Structure
With reference to FIGS. 1 and 4, the leg cradle 12 detachably connects to the support strut 14 via an interconnecting structure 16 positioned near the intersection between the first and second portions 30, 32. The interconnecting structure 16 permits quick detachment of the support strut 14 from the leg cradle 12 and permits the user to adjust the support strut's position relative to the vertical axis "a" of the cradle 12.
In the illustrated embodiment, best seen in FIGS. 1, 6A and 6B, the interconnecting structure comprises a plurality of studs 70 that depend from the leg cradle. These studs 70 generally extend parallel to the vertical axis "a." FIGS. 6A and 6B show the studs 70 projecting from the underside of the cradle 12. The studs 70 desirably form a geometric pattern that, in the illustrated embodiment, is a rectangle 72.
A connecting plate 74 is mechanically secured to the studs 70. As seen in FIGS. 6A and 6B, the connecting plate 74 includes a plurality of holes 80 arranged in sets of geometric patterns that correspond with the geometric pattern 72 of studs 70. There are preferably at least two sets of hole patterns 84, 86 that ensure proper mating of the plate 74 to the studs 70 and define at least two positions of the support 44 relative to the front wall of the first portion 30. To attach the connecting plate 74 to the studs 70, and, thus, secure the socket sleeve 76 to the leg cradle 12, a plurality of wing nuts 90 may be used to securely tighten the connecting plate 74 against the cradle 12.
By providing a plurality of hole patterns which mate with the plurality of studs 70, a user may adjust the support strut 14 with respect to the leg cradle 12 to more closely define a collinear relationship between the user's femur and the support strut 14, where desired. FIG. 1 shows the support strut 14 in collinear alignment with the longitudinal axis "a" of the first portion 30 and the user's femur. By doing so, the present leg support crutch 10 transfers the weight of the user's body through the femur to the support strut 14 and minimizes stress to the user's knee from the shear and torsional forces that may result from misalignment of the strut 14 and the femur. In effect, adjustability permits the user to place the strut in a location that most comfortably permits ambulatory movement.
As seen in FIG. 1, the connecting plate 74 supports a socket sleeve 76 for detachable holding the support strut 14 to the leg cradle 12. The socket sleeve 76 includes a hole 78 therethrough that receives the detent balls of the quick-release fastener 50 to releasably lock the strut 14 to the socket sleeve 76.
FIG. 1 also shows the support strut 14 securely fastened to the cradle 12. The connecting socket 76 slidably receives the upper end of the smaller diameter tube 46 which is locked in a seated position within the connecting socket 68 by the quick-release mechanical fastener 50. The quick-release feature is advantageous in that a user may quickly detach the support strut 14 from the leg cradle 12 when the user decides to sit down, as shown in FIG. 4.
Fasteners
FIGS. 1 through 3 best illustrate the plurality of fasteners 20, 22, 24, 26 used to secure the user's leg within the cradle. The fasteners 20, 22, 24, 26 are supported on the leg cradle 12 in a manner that permits effective securement to the user during use. In the illustrated embodiment, there are four fasteners that are include straps 100, 102 made of nylon, each threaded through a plurality of slots 104 provided in the leg cradle 12. The straps 100 of the upper two fasteners 20, 24 are preferably wider than the straps 102 of the lower two fasteners 24, 26. The difference in width reflects the difference in both the magnitude of the forces borne by the thigh as compared to the lower leg, as well as the size of the thigh as compared to the size of the lower leg. FIG. 5 illustrates the position of the slots 104 and the relative size of the preferred straps 100, 102 more clearly.
The positions of the fasteners 20-26 in the present invention and the number thereof are important in achieving the improved level of comfort and effectiveness described herein. In the preferred embodiment, there are two fasteners 20, 22 associated with the first portion 30 of the cradle 12 and two fasteners 24, 26 associated with the second portion 32 of the cradle; however, more fasteners can be used. Providing multiple fasteners associated with each cradle portion more effectively distributes the load carried by the user's leg positioned within the cradle and eliminates potential rocking about a single fastener point of contact when only one fastener is used.
The first fastener 20 is preferably placed at an upper end 106 of the first portion 30 of the cradle 12 away from the intersection between the first and second portions 30, 32. During use, while the user is in stride, the interaction between the strut 14 and the ground as the user walks have a tendency pull the first portion upper end away from the user's thigh, thereby causing the cradle to rotate about the user's knee. (This rotational axis is normal to the intersection of the longitudinal axes "a", "b"). Additional rotational forces are also experienced about generally the same axis due to the downward force of the user's leg weight caused by the lower leg being cantilevered beyond the second portion 32 of the cradle 12. While the rigid construction of the leg cradle 12 and the support strut 14 (as implemented by the interengaging structure 16) will effectively resist these rotational forces, the user's thigh must necessarily bear some of that resistance. The first portion 30 is, thus, a moment arm about the axis of rotation through the user's knee. The longer the moment arm, the less force will be transmitted at the first fastener 20 due in acting upon and reacting to the rotational forces. In other words, on the down stroke of the present leg support crutch, the ground (and the weight of the lower leg) will exert a rotational force that tends to push the first portion 30 of the cradle 12 against the user's thigh. The longer the first portion 30, the greater the area of engagement between the first portion 30 and the user's thigh, thus distributing those forces to a greater extend and minimizing the forces experienced by the thigh.
On the upstroke, however, the user's forward momentum will translate into forces that tend to pull the first portion 30 away from the user's thigh. By placing the first fastener 20 as close to the distal end 106 of the first portion as feasible and, thus, maximizing the moment arm as measured by the location of the first fastener 20, the force transmitted to the thigh when the present leg support crutch is in use is minimized. Thus, the present invention minimizes the force exerted on or by the thigh by extending the moment arm of the first portion 30 as far as possible and selectively placing the first fastener 20 very close to the distal end of the first portion 30.
The second fastener 22 is preferably placed proximal the intersection of the first and second portions 30, 32 but sufficiently spaced therefrom to avoid constriction of the popliteal fossa and popliteal artery contained therein. Prolonged constriction of the popliteal artery may result in irreparable damage and may diminish recuperation efforts, besides causing discomfort and pain. The present leg support crutch avoids such constriction by selectively placing the second fastener 22 above the intersection of the first and second portions 30, 32.
The third and fourth fasteners 24, 26 are provided in the second portion 32 of the cradle 12 and are positioned such that the third fastener 24 is located about the longitudinal mid-point of the user's calf and the fourth fastener 26 is located at the narrowing portion of the user's calf and near the user's ankle, that is generally at the second portion's outer end. Although relatively minimal, some forces will be experienced by the lower leg on the upstroke of the user's gait. Thus, it is preferably that the third fastener 24 be positioned at the mid-point of the calf where the lower leg may sustain the most force. The fourth fastener 26 positioned at the bottom of the calf and close to the ankle serves to stabilize the lower leg and maintain the user's foot in a comfortably restrained position to enhance recuperation.
With reference to FIG. 5, the first and second fasteners 20, 22 each preferably include two discrete strap segments, a first strap segment 108 and a second strap segment 110. At a first end of each first strap segment 108, a fastening mechanism 114 is provided for detachably affixing the strap segment 108 to a corresponding fastening mechanism 118 on the exterior of the leg cradle 12. Preferably the detachable fastening mechanism is a hook and loop fastener, such as Velcro®, with the hook portion (114) provided on the first strap segment 108 and the loop portion (118) provided on the exterior of the leg cradle 12. Similarly, at a first end of each second strap segment 110, a similar detachable fastening mechanism 116, such as a hook fastener, is also provided to mate with a corresponding loop fastener (not shown) provided on the exterior of the leg cradle 12 on the opposite side of the cradle 12 from the loop portion 118. The first and second strap segments 108, 110 may then be buckled together behind the user's thigh to adjust the straps as tightly as desired. It should be noted that any arrangement of one or multiple straps may be employed to effectively fasten the first portion 30 to the user's thigh.
In the illustrated embodiment, the third and fourth fasteners include a single strap segment 112, each of which slidably moves within the slots 104 within the second portion 32 of the leg cradle. If desired, the third and fourth straps may also include hook fasteners to engage loop fasteners affixed to the underside of the lower portion to prevent undesired sliding of the straps 112. The straps may be buckled around the user's lower leg to comfortably restrain the lower leg within the leg cradle 12.
Although this invention has been described in terms of a certain preferred embodiment, other embodiments apparent to those of ordinary skill in the art are also within the scope of this invention. Accordingly, the scope of the invention is intended to be defined only by the claims that follow.
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A single leg support crutch provides improved stability and balance to a user, who suffers from foot, ankle or lower leg injury, in order to enhance ambulatory movement of the user during recuperation. The leg support crutch comprises a unitary leg cradle that conforms generally to a user's thigh, knee and lower leg, and a plurality of fasteners that comfortably secure the leg support crutch to the user's leg while in a bended position. A support strut is releasably attached to the cradle and is positioned to support the weight of the user when standing or walking. A releasable coupling attaches the strut to the cradle at one of a plurality of locations. The multiple locations of the strut on the cradle allow the position of the strut to be adjusted in order to properly align the axis of the strut with the location of the user's femur in the cradle. As a result, the weight of the user is transferred more efficiently to the strut to improve the user's comfort when standing or walking.
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This application is a continuation of application No. 09/601,076, filed Feb. 20, 2001, U.S. Pat. No. 6,716,790 which is the national phase under 35 U.S.C. §371 of prior PCT International Application No. PCT/GB98/03004 which has an International filing date of Oct. 7, 1998, which designated the United States of America, and which was published by the International Bureau in English on Oct. 7, 1999, and which claims the benefit of South African Application No. 98/2737 filed Apr. 1, 1998.
This invention relates to catalysts. More particularly the invention relates to a method of making breakage resistant self-supported precipitated iron-based Fischer-Tropsch catalyst particles, to a method of making self-supported precipitated iron-based Fischer-Tropsch catalyst particles having superior synthesis performance or activity, to catalyst particles made according to the methods, and to the use of said catalyst particles in a slurry bed Fischer-Tropsch reactor.
BACKGROUND OF THE INVENTION
U.S. Pat. Nos. 5,324,335 and 5,504,118 disclose the production of roughly spherical iron-based Fischer-Tropsch catalyst particles having diameters in the range of between 1 and 50 microns which are annealed by heating in air at about 316° C. (600° F.) to drive off residual moisture and to stabilise the catalyst. The annealing step i.e. the heating and gradual controlled cooling, converts the Goethite to Hematite whereafter the catalyst may be activated and used. According to these patents, the annealing does not lead to a breakage resistant or a superior performance catalyst particle.
South African Patent No. 90/7530 discloses the production of an iron-based Fischer-Tropsch catalyst including from 1 to 80% by mass of activated carbon. This catalyst shows improved breakage resistance over conventional catalyst, particularly where the particle diameters are below about 45 micron. The catalyst particle of this patent does not have superior synthesis performance and is expected to hydrothermally sinter at about 300° C.
A need thus exists for breakage resistant iron-based Fischer-Tropsch catalyst particles, in particular for use in a low temperature Fischer-Tropsch process, such as that carried out in a slurry bed reactor, for the production of, amongst others, wax and other syncrudes, as well as chemicals. The breakage resistant self-supported precipitated iron-based Fischer-Tropsch catalyst particles will ideally inhibit the formation of catalyst fines in the reactor thereby maintaining the performance of the reactor and reduce the contamination of down stream processes and catalysts by the catalyst fines.
In this specification, unless the context clearly indicates to the contrary, the term “fines” when used in relation to catalysts and catalyst particles is to be understood to mean particles which due to their dimensions, when present at a concentration of about 30% of the total catalyst, tend to reduce the performance of the solid separation system of a Fischer-Tropsch slurry bed reactor. Typically fines have a diameter of less than about 45 microns, usually about 22 microns.
A further long felt need which exists is that for self-supported precipitated iron-based Fischer-Tropsch catalyst particles having superior synthesis performance or activity, in particular for use in a low temperature Fischer-Tropsch process, such as that carried out in a slurry bed reactor, for the production of wax and other syncrudes, as well as chemicals.
BRIEF SUMMARY OF THE INVENTION
It is well expected that heat treatment of self-supported precipitated catalyst particles has a negative effect on the activity thereof. In particular, the catalyst particle surface area and pore volume are likely to be reduced at temperatures above 250° C. Those skilled in the art therefore generally tend to avoid such heat treatment of such Fischer-tropsch catalyst material.
Surprisingly it has now been found that the breakage resistance and the synthesis performance or activity of self-supported precipitated iron-based Fischer-Tropsch catalyst particles can be increased by the heat treatment thereof at temperatures of at least 250° C.
Accordingly, the invention provides a method of producing self-supported precipitated iron-based catalyst particles for use in a Fischer-Tropsch slurry-bed process, the said particles being breakage resistant and thus inhibiting the formation of catalyst fines, the method including the heat treatment of the said particles at a temperature of at least 250° C.
The heat treatment may be calcination of the said particles at a temperature of at least 250° C.
The heat treatment of the said catalyst particles may be carried out at a temperature of between 250° C. and 500° C., preferably between 320° C. and 500° C., more preferably between 360° C. and 390° C., most preferably at 380° C.
According to a second aspect of the invention, there is provided a method of producing self-supported precipitated iron-based catalyst particles for use in a Fischer-Tropsch slurry-bed process, the catalyst particles having a superior synthesis performance or activity under low temperature Fischer-Tropsch slurry-bed operating conditions, the method including the heat treatment of the said catalyst particles at a temperature of at least 250° C.
The heat treatment temperature of the method may be between 250° C. and 500° C., preferably between 320° C. and 500° C., more preferably between 360° C. and 390° C., most preferably 380° C.
Typically the said catalyst particles are maintained at the heat treatment temperature for at least 0.1 hours, preferably between 0.2 and 12 hours, more preferably between 0.5 and 4 hours.
According to a further aspect of the invention there are provided self-supported precipitated iron-based catalyst particles for use in a Fischer-Tropsch slurry-bed process, the said catalyst particles being produced according to a method of heat treatment of the said catalyst particles as described above.
According to yet a further aspect of the invention, there is provided a method of maintaining the performance of a solid separation system of a Fischer-Tropsch process slurry bed reactor where a reduction in performance is caused by an increase in catalyst particle fines in the slurry bed reactor, the method including the use of the catalyst particles as described above.
According to yet a further aspect of the invention, there is provided a process for synthesis of syncrudes and/or chemicals, for example, waxes, the process comprising the step of contacting a suitable synthesis gas, at suitable temperatures and pressures in a Fischer-Tropsch slurry-bed reactor, with self-supported precipitated iron-based Fischer-Tropsch catalyst particles as described above.
The process may be carried out in a suitable vessel, with unreacted reactants and gaseous product being withdrawn above the slurry bed, and separated liquid product also being withdrawn from the vessel.
Typical suitable operating temperatures for the process are temperatures in the range 160° C. to 280° C., or even higher for production of lower boiling point product.
Typical suitable operating pressures are pressures in the range 18 Bar to 50 Bar.
DETAILED DESCRIPTION OF THE INVENTION
The invention will now be illustrated by means of the following non-limiting examples:
BRIEF DESCRIPTION OF THE DRAWINGS
Table 1 provides data regarding catalyst physical properties as a function of calcination temperature.
Table 2 provides data regarding catalyst behavior after repeated jet impingement conducted on a sample that was heat treated at 300° C.
Table 3 provides data regarding Mössbauer spectroscopic parameters for both untreated standard catalyst particles and heat treated catalyst particles.
Table 4 provides data regarding on line quantification of catalyst fines for untreated and heat treated catalyst particles.
Table 5 provides data regarding mechanical strength of dried samples.
Graph 1 provides liquid product recovery rate as a function of cycle number for a synthesis run with untreated catalyst particles.
Graph 2 provides liquid product recovery rate as a function of cycle number for a synthesis run with heat treated catalyst particles.
Graph 3 illustrates the increase in catalyst activity after addition of calcined catalyst.
Micrograph 1 provides micrographs of on line uncalcined catalyst particles at magnifications of ×100, ×150, ×200, ×250, ×300, and ×500.
Micrograph 2 provides micrographs of on line heat treated catalyst particles at magnifications of ×100, ×150, ×200, ×250, ×300, and ×500.
EXAMPLE 1
This example illustrates that the heat treatment of self-supported precipitated iron-based Low Temperature Fischer Tropsch catalyst particles for slurry bed application results in an increase in the mechanical strength of the said catalyst.
For a laboratory microscale operation, 250 grams of pilot plant and commercially prepared catalyst was placed in a porcelain dish in a muffle furnace. The furnace was subsequently heated to the desired heat treatment temperature at a heating rate of 1° C./min. The heat treatment or calcination temperature (as indicated in Table 1 below) was maintained for 4 hours after which the furnace was allowed to cool down to below 100° C.
For larger scale operation the catalyst was fed from a hopper at room temperature to a portable pilot plant scale rotary kiln. This kiln had a refractory lining and was electrically heated. The dimensions of this equipment were as follows: length=2.1 m, diameter=0.47 m, inclination=2°, rotational speed=1 rpm. The average temperature inside the kiln was controlled at 385° C. The feed rate was varied around 30 kg/h which resulted in a residence time of close to 1 hour. 1500 kg of catalyst was heat treated in this manner.
A sample of catalyst particles that were heat treated according to the manner described above was subjected to a Jet Impingement test. In this test a jet of air is used to impinge fresh catalyst particles against a plate. The smaller than 22 micron fraction of jet impinged sample is normally taken as a measure of the catalyst particle mechanical strength. Table 1 shows the results that were achieved from this test. Standard pilot plant prepared catalyst particles, and standard commercially prepared catalyst particles were used as reference materials.
Table 2 also reflects the results obtained from a repeated jet impingement test conducted on a sample that was heat treated at 300° C. Repeated jet impingement results indicated that the heat treated catalyst particles are stronger even after the initial break-up. It can be concluded that heat treatment induces strength to the whole particle, and not only to the outer shell of the particle.
EXAMPLE 2
This example illustrates that heat treatment of standard self-supported precipitated iron based Low Temperature Fischer Tropsch slurry bed catalyst particles does not alter the iron phase composition nor the crystallinity of the said catalyst particles; but rather promotes the enhancement of the catalyst particles' mechanical strength.
The phase composition and relative crystallite size of both the untreated standard catalyst particles and the heat treated samples were determined by Mössbauer spectroscopy at 4.2 K. The parameters are presented in Table 3.
Both samples can be described as highly dispersed Fe(III)oxide. The Fe-phase has been identified as α-Fe 2 O 3 . The particles display superparamagnetic behaviour and from the quadropole splitting parameter the size of the primary particles was estimated as between 2 and 4 nm.
At 77 K the heat treated sample shows a slight increase in the Δ value, indicating a corresponding decrease in the primary particle size. Based on these results it would seem as if the heat treatment causes a restructuring or reordering of the ions making up the primary particle, thus leading to a state of lower energy i.e. a stronger particle.
EXAMPLE 3
This example illustrates that heat treatment of the catalyst particles results in a major improvement of the solid separation system performance of said catalyst particles as experienced in a semi-works pilot plant reactor.
The liquid product recovery rate as a function of cycle number for a synthesis run with untreated catalyst particles is depicted in Graph 1. The separation rate levels obtained from a synthesis run operating with these standard catalyst particles only reached a maximum of 350 relative units per hour.
Data for a similar synthesis run with heat treated catalyst is presented in Graph 2. The average liquid product recovery rate is clearly above 1000 relative units per hour.
EXAMPLE 4
This specific example illustrates that calcining or heat treating standard self-supported precipitated iron-based Low Temperature Fischer-Tropsch catalyst particles for slurry bed application results in a significant reduction of the amount of fines that the catalyst particles generate under normal Fischer-Tropsch synthesis conditions.
Particle size distributions of representative on line catalyst particle samples were obtained for periods when untreated and heat treated catalyst particles were run respectively as outlined in example 3 above. A comparison of the catalyst fines content is presented in Table 4. The heat treated catalyst clearly shows a dramatic decrease in the amount of fines present in the reactor.
Scanning electron micrographs of the above mentioned untreated and heat treated on-line catalyst particle samples are presented in Micrographs 1 and 2 respectively. The absence of fine catalyst particles in the heat treated sample is once again obvious for the heat treated version.
EXAMPLE 5
This example shows that there is a marked increase in activity of standard self-supported precipitated iron-based Fischer-Tropsch catalyst particles upon heat treatment. This is elegantly illustrated in Graph 3. The catalyst activity shows a continuous increase after the change to heat treated catalyst particles which is indicated by a vertical bar in Graph 3.
EXAMPLE 6
This example illustrates that removal of residual moisture from freshly prepared catalyst particles does not lead to mechanically stronger catalyst particles.
A sample of untreated standard catalyst particles was treated in a vacuum oven at 100° C. until the moisture content was half the original value. Both the untreated and the vacuum dried samples were subsequently subjected to a Jet Impingement (JI) test in order to measure their mechanical strength. The results are compared with a heat treated example in Table 5.
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The invention provides heat treated self-supported precipitated iron-based Fischer-Tropsch catalyst particles. The particles of the present invention are breakage resistant and exhibit superior synthesis performance. The invention also provides a method for producing said particles and a process for using said particles.
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BACKGROUND OF THE INVENTION
The invention relates to a method for circular grinding during the production of tools made of hard metal on a circular grinding machine that has a workpiece spindle head and a tailstock, whereby work commences using a round rod comprising a starting material.
According to the prior art known from commercial practice, as a rule work commences starting with round rods made of sintered hard metal. These rods then have a grinding overmeasure for the shaft region and are cut to the necessary tool length, or the starting bodies are brought to the required shaft dimension for their entire length using so-called centerless grinding and are then cut into lengths. From the bar pieces that were cut into lengths individually, the tool is then produced from the whole by grinding. For this, the hard metal tools are received during grinding between hollow center punches, tips, or in a chuck.
Grinding occurs either using the conventional grinding method or using the rough grinding method by means of diamond grinding wheels. In any case, multiple instances of re-chucking are required because first the individual bar pieces are produced by grinding and cutting into lengths, where necessary in the reverse sequence as well, and then in subsequent grinding processes that take place on other machines the tool contours are ground and cutting, gradation, spiral cutting, and the like occur.
The known methods in accordance with the prior art work satisfactorily, however they entail the risk of errors in the trueness of the run. These errors are related primarily to multiple instances of re-chucking. Even if work is performed with great attention to precision, such errors in the trueness of the run cannot always be avoided. They are entirely and unpleasantly noticeable on the finished tool. This is particularly true of high-speed processing, for instance in aircraft construction. In this case, cutting tools are used that work at speeds of 30,000 to 60,000 rpms. When processing the light metal parts that are widely used in aircraft construction, even the smallest error in the trueness of the run on the tool is disturbingly noticeable.
BRIEF SUMMARY OF THE INVENTION
The object of the invention is therefore to improve the method known from the prior art such that errors in the trueness of the run are avoided with certainty and at comparable production costs.
This object is achieved using the following method steps:
a) Gripping the round rod, whose length is a multiple of the length of a single tool, in a chuck of the workpiece spindle head that when the chuck is released enables axial displacement of the round rod, whereby an end region of the round rod that projects out of the workpiece spindle head faces the tailstock;
b) Grinding at least one steady rest on the end region of the round rod that projects from the workpiece spindle head and placing the steady on the steady rest;
c) Grinding a first end-face taper on the end face of the round rod that faces the tailstock;
d) Secure-clamping fitting of the first end-face taper with a hollow center punch that is located on a sleeve of the tailstock;
e) Circular grinding of the end region of the round rod that projects from the workpiece spindle head over approximately the entire length that corresponds to the individual tool up to its circular-ground final contour;
f) Cutting off the thus finish-ground individual tool from the round rod;
g) Releasing the chuck of the workpiece spindle head, which to this point has remained clamped, moving the round rod in the workpiece spindle head in the direction of the tailstock, and then loading the chuck, whereby an additional end region of the round rod, which end region is to be processed, projects from the workpiece spindle head.
According to the inventive method, thus “work is performed on the running rod”. For this, the round rod that comprises sintered hard metal and that can for instance have a length of 300 to 400 mm, is gradually moved through the chuck of the workpiece spindle head and securely clamped each time a specific end region of the round rod that approximately corresponds in length to the tool to be produced projects from the workpiece spindle head and faces the tailstock. The special feature of the inventive method is that the projecting end region, even while it is joined to the rest of the round rod, is ground down to its circular-ground final contour. The circular-ground final contour of the hard metal tool to be produced is that contour of the finished tool that is to be produced by circular grinding. Then cutting, spiral cutting, and the like are performed on the tool in subsequent methods.
Since the end region projecting from the workpiece spindle head can have a considerable length depending on the tool, it is necessary to grip it at its free end, which is another reason a very precise contour is required. Therefore in the inventive method initially at least one steady rest is ground onto the free projecting end region. Then, if the end region is supported by means of the at least one steady rest on one or a plurality of steadies, a first end-face taper can be ground with the required precision onto the end face of the round rod, that is, of its end region, that faces the tailstock. The end-face taper is then fitted in a securely clamped manner with a hollow center punch on a sleeve of the tailstock. The end region is now again gripped at its two ends without it having been necessary to release the first clamping in the workpiece spindle head. Circular grinding can again be performed with the required precision on the already described circular-ground final contour.
Then the thus finish-ground individual tool is cut off from the round rod; the chuck of the workpiece spindle head, which to this point has remained clamped, is released, and the round rod is moved forward a bit in the released chuck in the direction of the tailstock, whereby another end region of the round rod that is to be processed projects from the workpiece spindle head.
In the present context, the description of a “thus finish-ground individual tool” is somewhat different from finish-grinding in the sense of finish-cut as opposed to rough-turned. Nor does it mean that the hard metal tool to be produced must now be ready for use. On the contrary, here the term finish-ground merely means that the resulting hard metal tool is as finish-ground in its first clamping as is the object of the circular grinding, that is, just to its desired circular-ground final contour.
The advantages of the inventive method are comprised above all in that multiple clamping is avoided. Thus re-chucking errors are avoided, and the result is the best circular trueness of the run results and shape and position tolerances relative to the shaft and cut part. Despite higher acquisition costs for the circular grinding machine, the costs for the individual workpiece are reduced because the resulting tool is processed in a single machine from unmachined part to rough-finished part or even finished part. Furthermore, through-times are reduced, and it is possible to react very rapidly to an order for a specific hard metal tool because the desired end regions can be cut off of the round rod in different lengths. Thus, finally, the stored inventory of semi-finished products can be reduced because production is flexible and rapid.
One advantageous further development of the inventive method is comprised in that during circular grinding of the end region of the round rod that projects from the workpiece spindle head, the steady is retracted from the steady rest. The steady acts primarily to grind with the greatest possible precision the clamped end of the end region of the round rod that projects from the workpiece spindle head and that faces the tailstock. On the other hand, the grinding of the workpiece contour can occur without additional support from steadies. This simplifies processing, and it is possible to attain with nothing further a perfect surface of the circular-ground final contour.
In the case of high demands in terms of precision, even for thin round rods, two steady rests can be ground axially spaced from one another on the end region of the round rod. In many cases, that is, with shorter hard metal tools, only one steady rest will be adequate, however.
Another advantageous embodiment of the inventive method is comprised in that the end region of the round rod that projects from the workpiece spindle head is separated from the remaining round rod after circular grinding in that with a single grinding wheel first with the round rod rotating a second end-face taper is ground on the end face of the thus finished tool that faces the workpiece spindle head and then after the grinding wheel has been retracted and axially displaced relative to the round rod a separating cut leaving only a central connecting band is applied and finally after the rotational movement of the round rod has ceased the separation process is concluded by grinding off the connecting band.
Using this approach, the projecting end region of the round rod remains joined to the rest of the round rod until the last possible moment, namely, via the central connecting band. Thus two-sided clamping of the end region without repeated re-chucking is possible until the very end, and processing accuracy is further enhanced without additional complexity. Furthermore, grinding can proceed on the rotating round rod for as long as possible, which is advantageous for the thermal stress on the resulting tool.
When the finish-ground individual tool has been finally cut off, the tailstock and/or the sleeve are then retracted from the resulting finished tool, and the tool is held by a clamping unit. Once the separating process has concluded, the clamping unit can remove the thus finished tool from the machine and deposit it, further enhancing the efficiency of the method.
The known circular grinding techniques can be used for the most important process of circular grinding in accordance with method step e) above. Thus the circular grinding can occur for producing the tool contour with a narrow grinding wheel in the rough grinding method and/or with a wide grinding wheel in a pendulum grinding method.
The inventive method can be performed both in a nearly manual procedure and in a highly automated design. In the latter case, care must be taken above all that the last rod piece to be processed is not gripped in the chuck of the workpiece spindle head with an axial extension that is not long enough. If this happens errors occur that are due to poor trueness of the run as a result of the gripping length being too short. Incomplete chucking can lead to damage of the machine or even accidents if the proper care is not exercised. In order to prevent this, in accordance with another embodiment of the inventive method it is provided that the rest of the length of the round rod that remains available for moving the round rod through the chuck of the workpiece spindle head is checked at least during every chucking process and when it does not meet a certain minimum remaining length a signal is given and/or the circular grinding machine is stopped.
In this manner the greatest possible safety is provided for the method.
The invention also relates to a circular grinding machine for grinding cylindrical starting bodies during the production of tools made of hard metal.
Such an inventive machine is provided with a machine bed, with a grinding table that can travel on the machine bed and on which are arranged a workpiece spindle head and a tailstock, with a chuck on the workpiece spindle head that enables a round rod acting as a starting material to be moved through and chucked in different axial positions, with at least one steady arranged in the region between the workpiece spindle head and the tailstock and with a gripping unit arranged in the same region, whereby an end region of the round rod that has been moved through the chuck of the workpiece spindle head and securely clamped can additionally be held selectively by the tailstock and/or the steady and/or the gripping unit, and with at least one grinding spindle head with one or a plurality of grinding spindles and that can be used to position one or a plurality of different grinding wheels at the round rod.
Thus, in the inventive machine a number of features cooperate such that the described advantages of the method can be attained. In addition to the chuck of the workpiece spindle head, which permits the round rod comprising hard metal to be moved through and gradually clamped, the numerous devices for supporting the projecting end region of the round rod are also necessary, that is, the tailstock, the one or a plurality of steadies, and selectively also the gripping unit. The cooperation of all of these individual parts is necessary in the prescribed sense so that the hard metal tools can be produced economically and yet with great precision.
Fundamentally it is possible with the inventive circular grinding machine to make due with a single grinding wheel if it is caused to engage the round rod in an inclined position.
In this manner the end-face taper can be applied to the two ends of the resulting tool, while when the grinding wheel and round rod are set parallel, circular grinding can be performed to the desired final contour. However, it is preferred when in accordance with one embodiment of the inventive circular grinding machine a grinding spindle head is provided that carries two grinding spindles and that can be pivoted about a pivot axis that is oriented perpendicular to a plane in which lies the common axis for workpiece spindle head, round rod, and tailstock.
In this manner two different grinding spindles can be brought into the working position rapidly, each of these grinding spindles being able to carry a plurality of grinding wheels.
Particularly preferred is the arrangement of a multiple grinding wheel in which two or more grinding wheels of differing diameter, differing width, and/or differing exterior contour are located immediately adjacent to one another on a common driven axis.
In this manner a very specific grinding wheel that is specially embodied for a specific procedure is employed without interference from the grinding wheel located immediately adjacent thereto. For instance, of two adjacent individual wheels, the one can be embodied for circular grinding in the rough grinding method while the other, with a spherical grinding contour, grinds an end-face taper in the optimum manner.
When there is a demand for greater numbers of these multiple grinding wheels, it can also be advantageous that the different grinding wheels are combined into a common grinding body. There is then an adapted shaped grinding body for which only a single carrier body is required.
The inventive circular grinding machine can be advantageously provided with CNC control, which then largely automates the entire grinding procedure.
Given the problems described in the foregoing because of which it is necessary especially in a highly automated procedure to automatically monitor the grinding procedure, in accordance with another advantageous embodiment, allocated to the chuck of the workpiece spindle head is a sensor that checks the remaining length of the round rod that is available for moving the round rod through the chuck, at least during every chucking procedure, and when a minimum remaining length is not met provides a signal and/or stops the circular grinding machine.
In such an embodiment a situation is avoided with certainty in which the last remaining piece of a round rod that does not have a clamping length that is long enough is ground, which can easily result in errors or even accidents.
In addition, in the inventive circular grinding machine, a tailstock with a sleeve carrying a hollow center punch is used in an advantageous manner. A hollow center punch is particularly well suited for centering the end-face taper of a cylindrical part and securely receiving it.
The inventive method and the inventive circular grinding machine are not only particularly well suited for grinding hard metal tools, but also for all workpieces with similarly borne contours and problems.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is explained in greater detail using the exemplary embodiments depicted in the following figures in which:
FIG. 1 is a view from above of a grinding machine for performing the inventive method;
FIG. 2 depicts the details of the grinding machine in accordance with FIG. 1 during grinding of steady rests;
FIG. 3 is an illustration corresponding to FIG. 2 depicting the grinding of an end-face taper on the round rod;
FIG. 4 illustrates all of the options for gripping the end region of the round rod that projects from the workpiece spindle head.
FIG. 5 in addition illustrates the gripping unit that is employed when separating the end region from the round rod;
FIGS. 5 a , 5 b , and 5 c illustrate the sequence of the separation procedure after circular grinding of the resulting tool;
FIG. 6 schematically depicts the transition to circular grinding of the following end region on the round rod; and
FIG. 7 illustrates two different hard metal tools in the condition of their circular-ground final contour.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is the simplified view from above of a grinding machine for performing the inventive method. The machine bed is labeled with the number 1 , and in the front region a grinding table 2 is placed on it. The grinding table 2 can travel in the direction of the axis Z by means of a CNC control. Placed on the grinding table 2 on the left-hand side is a workpiece spindle head 3 that receives a chuck 4 that is driven rotationally by means of an electromotor (not shown). The chuck 4 can be seen at the front of the workpiece spindle head 3 . It is used to grip the workpiece, in this case the round rod 6 . The chuck 4 is embodied such that the round rod 6 can be moved through the chuck and securely clamped in the desired axial positions by means of the clamping jaws 5 ( FIG. 2 ). Positioned opposite the workpiece spindle head 3 on the grinding table 2 is a tailstock 7 that receives a sleeve 8 that can travel in the axial direction. The arrow 9 indicates the sleeve movement. The exterior end of the sleeve 8 that faces the workpiece spindle head 3 is embodied as a hollow center punch 10 and receives the end of the round rod that is ground to an end-face taper.
Two steadies are labeled 11 and 12 and they can be positioned for providing additional support at the end region of the round rod 6 . The arrows 13 and 14 in FIG. 2 indicate the direction of movement of the steadies 11 and 12 .
The round rod 6 , the workpiece spindle head 3 , the chuck 4 , the sleeve 8 , and the tailstock 7 form a common center axis 15 that can also be called a common functional axis.
Also in FIG. 1 there is a grinding spindle head 16 that carries a first grinding spindle 17 and a second grinding spindle 18 . The first grinding spindle 17 is fitted with a first grinding wheel 20 and the second grinding spindle 18 is fitted with a second grinding wheel 21 . The grinding spindle head 16 can be pivoted about a first pivot axis 19 that is oriented perpendicular to a plane in which lies the common axis 15 of the workpiece spindle head 3 , round rod 6 , and tailstock 7 . As can be seen with nothing further from the illustration in accordance with FIG. 1 , the first grinding wheel 20 or the second grinding wheel 21 can be selectively moved into the working position by pivoting the grinding spindle head 16 about the pivot axis 19 . Moreover, the grinding spindle head 16 can also travel linearly in the direction of the X axis. The travel in the direction of the X axis is also CNC-controlled. The grinding spindles 17 and 18 contain integrated electromotors that drive the grinding wheels 20 , 21 rotationally.
Further illustrated in FIG. 1 is a sensor 42 which is allocated to the chuck 4 of the workpiece spindle head 3 . The sensor 42 checks the remaining length of the round rod 6 that is available for moving the round rod 6 through the chuck 4 , at least during every chucking procedure. When a minimum remaining length of the round rod 6 is not met, the sensor 42 provides a signal and/or stops the circular grinding machine.
Additional details of the circular grinding machine illustrated in FIG. 1 are found in FIGS. 2 through 4 .
Thus in FIG. 2 the clamping jaws 5 of the chuck 4 can be seen that clamp the round rod 6 for the grinding procedure. As stated, the round rod 6 can be moved through the chuck 4 and securely clamped in a selectable axial position. When this happens, an end region 23 of the round rod 6 projects out of the chuck 4 and the workpiece spindle head 3 . The length of the end region 23 is approximately equal to the length of the hard metal tool to be produced plus a certain clamping and processing length (see FIG. 5 ).
FIG. 5 also schematically illustrates a gripping unit 22 whose clamping parts 24 and 25 can grip and hold the end region 23 of the round rod from the outside. The arrows 26 , 27 indicate the movement of the clamping parts 24 , 25 .
FIG. 2 illustrates how the first grinding spindle 17 of the grinding spindle head 16 travels into the working position. The first grinding wheel 20 is illustrated enlarged. It has a base body 28 with a larger axial extension and a narrow region 29 projecting radially therefrom. The narrow region 29 carries the grinding coating 30 that has a cylindrical contour. The grinding wheel 20 is for instance embodied as a diamond grinding wheel with a grinding coating that is approx. 5 mm high.
In contrast, in FIG. 3 the second grinding spindle 18 with the second grinding wheel 21 is in the working position. The second grinding wheel 22 has a first individual wheel and a second individual wheel 32 . The second grinding wheel can be embodied as a multiple grinding wheel. However, the two individual wheels 31 and 32 can also be called parts of a common grinding body with a single base body. The grinding coatings of the two individual wheels 31 and 32 are labeled 33 and 34 . The two individual wheels 31 and 32 have a different axial thickness and are both fitted with conical grinding surfaces that have opposing inclines.
In accordance with the illustration in FIG. 5 , as well, the second grinding spindle 18 with the second grinding wheel 21 is employed.
The other machine parts that are illustrated in FIGS. 2 through 5 have the previously mentioned reference numbers and are therefore not detailed individually.
The grinding procedure to be performed on the grinding machine in accordance with FIGS. 1 through 6 occurs in the following manner:
The starting material is the previously mentioned round rod 6 made of a sintered hard metal. Such a round rod, which can have for instance a length of 300 to 400 mm, is moved through the chuck 4 of the workpiece spindle head 3 until an end region 23 ( FIG. 2 ) of the desired length projects from the chuck 4 . In this position the clamping jaws 5 are moved against the round rod 6 so that the latter is securely clamped.
Then the first grinding spindle 17 of the grinding spindle head 16 is brought into the working position. Thus a first steady rest 35 is ground into the end region 23 of the round rod 6 by means of the first grinding wheel 20 that is located on the first grinding spindle 17 and that is rotatingly driven. Then the first steady 11 is moved in the direction of the arrow 13 against the first steady rest 35 so that the end region 23 is securely supported during further grinding procedures.
When necessary, a second steady rest 36 or additional steady rests can be ground into the end region 23 of the round rod 6 . The second steady 12 is provided for this, for instance. During this, the steady rest 36 , which is arranged closer to the chuck 4 , is then ground first and then the steady rest 35 is ground.
In accordance with the illustration in accordance with FIG. 3 , both steadies 11 and 12 are placed against the associated steady rests 35 , 36 . The end region 23 is thus securely supported. Now the second grinding spindle 18 with the second grinding wheel 21 is brought into the working position. Its first individual wheel 31 then grinds a first end-face taper 37 into the end face of the round rod 6 , that is, its end region 23 , that faces the tailstock 7 . The first end-face taper 37 is dimensioned such that it fits into the hollow center punch 10 of the sleeve 8 that is displaceably arranged in the direction of the arrow 9 in the tailstock 7 .
FIG. 4 illustrates the condition in which the free end of the end region 23 with the first end-face taper 37 is securely gripped in the hollow center punch 10 . Located in the working position again is the first grinding spindle 17 of the grinding spindle head 16 , which is again positioned in the direction of the X axis at the end region 23 CNC controlled. At the same time, the grinding table 2 travels CNC-controlled in the direction of the Z axis. In this manner nearly the entire length of the end region 23 is circular ground in the rough-grinding procedure by means of the first grinding wheel 20 . This means that this length is ground in a single procedure of the grinding wheel 20 on the end region 23 . However, it is also possible to use a wider grinding wheel and to perform the procedure in the pendulum grinding method. In this case, there are then a plurality of radial positioning movements, and the longitudinal movement must be repeated multiple times until grinding overmeasure 38 is carried off and the desired surface condition of the end region 23 has been attained.
FIG. 4 illustrates a condition in which the steadies 11 and 12 are also positioned against the end region 23 during this part of the procedure. However, this is by no means required. The use of the steadies 11 and 12 is primarily unavoidable when the first end-face taper 37 is being ground. In the following procedures, work can also be performed in that the steadies are then retracted.
The procedure of circular grinding illustrated in FIG. 4 is by no means limited solely to obtaining a continuously cylindrical contour of the desired surface quality. On the contrary, in this method step the entire circular-ground final contour of the resulting finished hard metal tool should be attained. That is, depending on the final contour of the tool, partial regions can already be ground out with cylindrical, tapered, or spherical contours in this stage of the method in which the end region 23 is still situated on the round rod. All contours that can be obtained by circular grinding are conceivable. This can also occur in that a set of grinding wheels with different are employed. This is not illustrated in FIG. 4 , however.
FIG. 7 illustrates examples of such circular-ground final contours.
The end region 23 of the round rod 6 and thus the resulting hard metal tool are therefore thus finish ground. The term “finish grinding” here does not mean finish grinding in the sense of smoothing as opposed to roughing, but rather the most final stage that can be attained for the resulting tool by circular grinding. Then cutting, spiral cutting, and the like must be performed in separate methods. First, however, it is necessary to separate the thus finish-ground tool from the round rod 6 .
The procedure is explained using FIGS. 5 and 5 a through 5 c . The final region 23 of the round rod 6 is first still clamped at both ends, as illustrated in FIG. 4 . One or a plurality of steadies can be positioned at the end region 23 ; however, this is not required. Deviating from the illustration in accordance with FIG. 4 , the second grinding spindle 18 is brought into the working position in that the grinding spindle head 16 is pivoted about the pivot axis 19 . Now the second individual wheel 32 of the second grinding wheel 21 , which is a multiple grinding wheel and which has a larger diameter than the first individual wheel 31 , is employed. The rotating second individual wheel 32 is then positioned against the also rotating end region 23 of the round rod 6 . This first positioning procedure is then interrupted as soon as the second individual wheel 32 has ground the second end-face taper 39 ( FIG. 5 a ).
Then the second grinding wheel 21 is retracted from the end region 23 of the round rod 6 . The round rod 6 and the second individual wheel 32 are mutually offset axially relative to one another. The offset is approximately the thickness of the second individual wheel 32 . Then the individual wheel 32 is again positioned against the end region 23 of the round rod 6 and this time effects a separating cut 40 . The procedure is continued until the connection between the remaining residual length of the round rod 6 and its end region 23 comprises only a narrow connecting band 41 . Until this point the end region 23 of the round rod 6 was clamped at its two ends and driven to rotate ( FIG. 5 b ).
Then the rotational drive of the workpiece spindle head is stopped, and the tailstock 7 with the sleeve 8 is retracted from the clamping position. The end region 23 of the round rod 6 with the first end-face taper 37 is now free and is enclosed and securely held by the clamping parts 24 , 25 of the gripping unit 22 . Further positioning of the second individual wheel 32 then continues the separating process and the connecting band 41 is also ground off ( FIG. 5 c ). The tool, which is finished in terms of circular grinding, is now separated from the remainder of the round rod 6 and thus finished. The resulting hard metal tool is held in the gripping unit 22 and is removed from the machine and deposited by the gripping unit (see FIG. 5 ).
Then the round rod is again moved out of the chuck 4 a bit so that the next end region 23 can be processed ( FIG. 6 ).
FIG. 7 illustrates two different hard metal tools in one stage as can be attained with the inventive method and the inventive circular grinding machine. The second end-face taper can be seen on the illustrated, thus finish-ground tools at their one end. The original cylindrical contour of the round rod 6 is illustrated with the dashed lines, so that it can be seen how the desired circular-ground final contour was obtained solely by circular grinding. The figure makes it possible to see clearly that graduated cylindrical, tapered, or spherical contours can be obtained with nothing further. The special aspect of this is comprised in that these numerous shapes were created, whereby at least at the one end a single clamping of the round rod forming the starting material was sufficient.
It should be remarked that the performance of the method is not limited to the measures depicted in FIGS. 1 through 5 . It is even possible to make do with a single grinding wheel for all of the procedures when it is possible to position this grinding wheel in an inclined position against the round rod.
The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not as restrictive. The scope of the invention is, therefore, indicated by the appended claims and their combination in whole or in part rather than by the foregoing description. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope.
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A grinding method and to a cylindrical grinding machine grinds metal rod that is pushed through a chuck of a workpiece spindle head. Two backrest seats are ground on and two backrests are then seated. The support of an end area enables a front cone to be ground. A grinding wheel comprised of two different individual wheels serves to grind the front cone and is advanced toward the round rod in the X-direction. The front cone is lodged in a hollow punch at a front end of a quill by displacement of the quill. The desired cylindrical grinding a final contour of the end area is done. Working the rod is done with a single chucking and the end area is cut off from the round rod by one of the individual wheels.
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[0001] This application is being filed on 8 Oct. 2007, as a PCT International Patent application in the name of Donaldson Company, Inc., a U.S. national corporation, applicant for the designation of all countries except the US, and Paul R. Coulonvaux and Johnny Craessaerts, both citizens of Belgium, applicants for the designation of the US only, and claims priority to U.S. Provisional Patent Application Ser. No. 60/849,096, filed Oct. 6, 2006, and U.S. Provisional Patent Application Ser. No. 60/963,068, filed Aug. 1, 2007.
FIELD OF THE DISCLOSURE
[0002] The present disclosure concerns air cleaners with removable and replaceable (i.e., serviceable) filter cartridges. Methods of servicing are also provided.
BACKGROUND
[0003] Air filtering is used in a variety of arrangements. A typical application is as an air cleaner for intake air to internal combustion engines. After a period of use, filter media within the cleaner requires servicing, either through cleaning or complete replacement. Typically, for an air cleaner used within internal combustion engines such as on a vehicle, filter media is contained in a removable or replaceable (for example, serviceable) component, element or cartridge. Examples are shown in U.S. Pat. Nos. 4,211,543; 4,135,899; 3,672,130; 5,445,241; 5,700,304; 6,051,042; 6,039,778; 5,547,480; 5,755,842; and 5,800,581; and PCT Publication WO 89/01818 and WO 06/026241; the complete disclosures of all these references being incorporated herein by reference.
[0004] Improvements in filter arrangements relating to assembly and use, are desirable.
SUMMARY
[0005] An air cleaner assembly, a main filter element, and a method for servicing an air cleaner assembly are provided according to the present invention. The air cleaner assembly includes an air cleaner housing and a main filter element. The air cleaner housing includes a safety liner having a closed end cap that supports the main filter element.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 is a side, perspective view of a main cleaner assembly according to the present disclosure.
[0007] FIG. 2 is a cutaway, exploded, perspective view of components of the assembly of FIG. 1 .
[0008] FIG. 2 a is a cutaway, side, sectional view showing an alternative arrangement for attaching the safety liner to the air cleaner housing.
[0009] FIG. 3 is a perspective view showing attachment of the safety liner to the housing of the assembly of FIG. 1 .
[0010] FIG. 4 is a perspective view showing attachment of the safety liner to the housing of the assembly of FIG. 1 .
[0011] FIG. 5 is a cutaway, perspective view of components of the assembly of FIG. 1 .
[0012] FIG. 6 is a cutaway, perspective view of components of the assembly of FIG. 1 showing attachment of a safety media.
[0013] FIG. 7 is a cutaway, perspective view of components of the assembly of FIG. 1 showing attachment of a safety media.
[0014] FIG. 8 is a partial, sectional view of the assembly of FIG. 7 .
[0015] FIG. 9 is a cutaway, perspective view of the assembly of FIG. 7 showing attachment of the main filter element.
[0016] FIG. 10 is a cutaway, perspective view of the assembly of FIG. 7 showing attachment of the main filter element.
[0017] FIG. 11 is a cutaway, perspective view of the assembly of FIG. 1 .
[0018] FIG. 12 is a partial, sectional view of the assembly of FIG. 11 without the access cover.
[0019] FIG. 13 is a side, perspective view of an alternative air cleaner assembly according to the present disclosure.
[0020] FIG. 14 is a cutaway, exploded, perspective view of components of the assembly of FIG. 13 .
[0021] FIG. 15 is a cutaway, perspective view of a portion of the assembly of FIG. 13 .
[0022] FIG. 16 is a partial, sectional view of the assembly of FIG. 15 .
[0023] FIG. 17 is a cutaway, perspective view showing attachment of the safety filter media.
[0024] FIG. 18 is a cutaway, perspective view showing attachment of the safety filter media.
[0025] FIG. 19 is a partial, sectional view of the assembly of FIG. 18 .
[0026] FIG. 20 is a cutaway, perspective view showing attachment of the main filter element.
[0027] FIG. 21 is a cutaway, perspective view showing attachment of the main filter element.
[0028] FIG. 22 is a partial, sectional view of the assembly of FIG. 13 without the access cover.
[0029] FIG. 23 is a end view showing the slot on the closed end of the main filter element of FIG. 22 .
[0030] FIG. 24 is a partial, exploded view of the assembly of FIG. 11 .
DETAILED DESCRIPTION
[0031] Now referring to FIGS. 1 and 11 , an air cleaner assembly is shown at reference number 10 . The air cleaner assembly 10 includes an air cleaner housing 12 , a main filter element 14 , and a safety filter element 16 . The air cleaner assembly 10 can be applied in the filtering or cleaning of a variety of gases. The air cleaner assembly 10 is suited for cleaning air for use in an internal combustion engine, such as the engine of a vehicle such as a truck, bus, tractor, or construction equipment; or for a generator.
[0032] The air cleaner housing 12 includes an air inlet 18 and an air outlet 20 . In FIG. 11 , the air cleaner assembly 10 has been cutaway to show the internal components and, as a result, the air inlet 18 is not shown in FIG. 11 . Nevertheless, it should be understood that the air inlet 18 is present on the operable air cleaner assembly 10 . In general, dirty air or air in need of cleaning enters the air cleaner assembly 10 through the air inlet 18 , and clean air exits the air cleaner assembly 10 through the air outlet 20 .
[0033] The air cleaner housing 12 includes optional mounting legs or supports 22 thereon to facilitate mounting. Alternatively, the air cleaner assembly 10 can be mounted with a separate mounting band or bracket. The air cleaner assembly 10 can be provided in a variety of orientations. An exemplary orientation has the outlet 20 extending vertically. However, many of the principles and techniques described can be applied to air cleaner assemblies mounted in other orientations.
[0034] The particular air cleaner air cleaner housing 12 has a housing side wall 24 that can generally be considered as cylindrical in overall shape. The air inlet 18 can be referred to as a tangential inlet 26 that goes through the housing side wall 24 . The term “tangential” in this context is meant to indicate that a center line of the air inlet 18 is not directed toward a center access of the air cleaner assembly 10 , but rather is directed more tangentially. This causes the air entering through the tangential inlet 26 to begin movement in a swirling pattern. The swirling pattern is facilitated by the generally cylindrically shaped housing side wall 24 . Alternatively, the air inlet can be provided so that it is radial. That is, the air entering through the air inlet can enter in a radial direction toward a center of the air cleaner assembly.
[0035] The air cleaner air cleaner housing 12 includes a main housing 28 and a service cover 30 . For the particular air cleaner air cleaner housing 12 , parts of the main housing 28 and the service cover 30 form the housing side wall 24 . The service cover 30 is constructed so that it is removable from the main housing 28 . Latches 32 are available for holding the service cover 30 onto the main housing 28 . The particular latches 32 shown are a type of over center latch 34 . Other types of latches can be used. The service cover 30 includes a closed end 36 . In general, the characterization of a closed end means that mass air flow does not occur through the closed end 36 . That is, the closed end 36 does not operate as an air inlet or outlet during operation of the air cleaner assembly 10 .
[0036] The air outlet 20 can be characterized as a circular, axial, outlet 38 . By “axial” in this context, it is meant that a center line or axis of the outlet 20 extends parallel to a center line or axis of the air cleaner housing 12 . In the particular instance shown, the center line of the circular, axial, outlet 38 is coaxial with the center line of the air cleaner housing 12 . Of course, alternative configurations are available. For example, the air outlet can be eccentrically positioned relative to the center line of the air cleaner housing 12 .
[0037] The main housing 28 has a first end 29 and a second end 31 . The air outlet 20 extends through the first end 29 , and the air inlet 18 extends between the first end 29 and the second end 31 . The service cover 30 attaches to the main housing 28 at the second end 31 . The first end 29 and the second end 31 can both be characterized as open. The first end 29 can be characterized as open because of the presence of the air outlet 20 extending therethrough. The second end 31 can be characterized as open because the service cover 30 is removable from the first end 31 . When the service cover 30 is attached to the second end 31 , the air cleaner second end 35 can be characterized as closed. The air cleaner first end 33 can be characterized as open for the same reason that the main housing first end 29 is characterized as open.
[0038] Now referring to FIGS. 2-5 , assembly of the safety liner 40 as part of the air cleaner housing 12 is shown. The safety liner 40 includes an open support structure 42 , a safety liner closed end cap 44 , and a plurality of attachment tabs 46 at a downstream end 48 . The open support structure 42 is provided to support the safety filter element 16 , and allow air to flow therethrough to the open interior 50 of the safety liner 40 . During operation of the air cleaner assembly 10 , air that flows into the open interior 50 can generally be considered clean air and flows out through the air outlet 20 .
[0039] The attachment tabs 46 extend from the safety liner 40 so that they are capable of engaging openings 52 provided in the flange 53 of the air outlet 20 . The attachment tabs 46 can be provided so that they extend at about a 90 ° angle relative to the cylindrically extending direction of the safety liner 40 . The attachment tabs 46 can engage or fit within the openings 52 in the flange 53 . The flange 53 extends sufficiently far away from the outlet collar 55 to receive the attachment tabs 46 . As a result of a twisting movement of the safety liner 40 , the attachment tabs can extend beneath the flange 53 , and can snap into place within the snap fit opening 58 . As shown in FIGS. 3 and 4 , the attachment tabs 46 include a snap fit member 60 that fits within the snap fit opening 58 . Once the snap fit member 60 engages the snap fit opening 58 , the safety liner 40 can generally be considered to be locked in place and can be considered a part of the air cleaner housing 12 .
[0040] An alternative arrangement for attaching the safety liner 40 ′ to the air cleaner housing 12 ′ is shown in FIG. 2 a . The safety liner 40 ′ includes a flange 53 ′ extending radially away from the axis of the air cleaner along a circumference of the safety liner 40 ′. The flange 53 ′ includes openings (not shown but similar to openings 52 in the flange 53 ) for receipt of the attachment tabs 46 ′ extending radially from the air cleaner housing 12 ′. The attachment tabs 46 ′ can have a structure similar to the attachment tabs 46 except that they extend radially from the radial seal member 66 ′. In addition, the attachment tabs can include snap fit members, and the snap fit members can engage snap fit openings in the flange 53 ′.
[0041] Now referring to FIGS. 2 , 5 , and 8 , the safety liner closed end cap 44 can be characterized as having a spherical shape 45 . By a spherical shape, it is meant that the outside surface 47 is generally curved and provides an apex 49 at about the center of the safety liner closed end cap 44 . The safety liner closed end cap 44 can be provided with shapes other than a spherical shape.
[0042] Now referring to FIGS. 6-8 , the safety filter element 16 extends over the safety liner 40 . In FIG. 6 , the safety filter element 16 is shown being applied over or removed from the safety liner 40 . The safety filter element 16 includes a safety downstream seal member 62 and a safety end cap seal member 64 . The safety downstream seal member 62 is provided for sealing between the downstream end 48 of the safety liner and a radial seal member 66 that is part of the air cleaner housing 12 . The downstream end 48 of the safety liner can include a sealing surface 51 that can be considered part of the main housing 28 . The safety downstream seal member 62 fits between the sealing surface 51 and the radial seal member 66 to provide a seal.
[0043] The safety filter element 16 includes a media structure 68 . The media structure 68 is shown as a tri-layer structure including a first layer 70 , a second layer 72 , and a third layer 74 . The first layer 70 and the third layer 74 can be provided as media, and the second layer 72 can be provided as a support structure to support the safety filter element 16 so that it maintains its shape. Alternatively, the first layer 70 and the third layer 74 can be support structure, and the second layer 72 can be filtration media. Other alternatives are possible. For example, the media structure can be provided as a by-layer structure including one layer or two layers of filtration media. The media structure 68 extends within the downstream seal member 62 so that the media structure 68 extends between the downstream end 48 of the safety liner 40 and the radial seal member 66 . As a result, the media structure 68 assists in the seal between the downstream end 48 and the radial seal member 66 .
[0044] The media structure 68 extends into the end cap seal member 64 . The safety end cap seal member 64 provides a sealing engagement with the safety liner closed end cap 44 . The end cap seal member 64 provides an annular seal around the end cap periphery 61 . The safety end cap seal member 64 includes a gripping surface 63 that allows one to grasp the safety end cap seal member 64 and pull the safety filter element 16 off of the safety liner 40 .
[0045] Now referring to FIGS. 9-12 , placement of the main filter element 14 within the air cleaner housing 12 is shown. The characterization of a “main filter element” refers to the element that provides a majority of the air filtering function. The safety filter element is generally intended to protect the air inlet for the combustion engine during replacement of the main filter element 14 . Accordingly, when the main filter element 14 is removed from the air cleaner housing 12 , the safety filter element 16 remains in place to provide protection to the internal workings of the, for example, combustion engine.
[0046] The main filter element 14 includes a main filter element radial seal member 80 , a main filter closed end cap 82 , and filtration media 84 . An exemplary type of filtration media 84 that can be used includes pleated media 86 . The main filter element 14 can include a main filter element support 88 and a cover 90 to support and protect the filtration media 84 . The cover 90 can be provided as a mesh or screen.
[0047] In FIG. 9 , the service cover 30 has been removed from the air cleaner housing 12 and the main filter element 14 is being introduced into or removed from the housing interior 92 . As shown in FIG. 10 , the main filter radial seal member 80 forms a radial seal with the radial seal member 66 of the air cleaner housing 12 . The radial seal member 80 can be characterized as an inward facing radial seal member because the sealing surface is provided toward the inner portion of the main filter element 14 . In addition, it should be understood that the filtration media 84 can be potted within the first open end cap 81 that can contains the radial seal member 80 , and the second closed end cap 83 .
[0048] The closed end cap 82 includes an annular rim area 94 , a recess 95 , and a central bump 96 . The annular rim area 94 generally covers the filtration media 84 that extends annularly or cylindrically within the housing interior 92 . The filtration media 84 can be embedded within the main filter closed end cap 82 at the annular rim area 94 . The central bump 96 can be provided having a sufficiently spherical shape or other shape so that when the main filter element 14 is fully inserted within the housing interior 92 , the central bump 96 contacts or is supported by the safety liner closed end cap 44 . In a preferred arrangement, the central bump 96 does not contact the safety closed end cap 44 at the apex 49 , but does contact the safety closed end cap 44 or is supported by the safety closed end cap 44 along an annular area 97 between the apex 49 and the end cap periphery 61 . In general, the closer the annular area 97 is to the end cap periphery 61 , the larger the potential contact area. Increased contact area can assist with the stability of the main filter element 14 within the housing 12 . In order to provide this contact, the closed end cap 82 includes a recess 95 between the annular rim area 94 and the central bump 96 . The recess 95 can extend annularly between the annular rim area 94 and the central bump 96 .
[0049] The service cover 30 can be attached to the main housing 28 and latched in place. The service cover 30 can include a service cover annular rim area 102 , a service cover central bump 104 , and a service cover recess 106 . In general, the service cover annular rim area 102 , the service cover central bump 104 , and the service cover recess 106 can be provided so that they generally correspond with the closed end cap annular rim area 94 , the closed end cap central bump 96 , and the closed end cap recess 95 . The service cover can help hold the main filter element 14 in place within the housing 12 . The service cover annular rim area 102 can help push the main filter element 14 in place.
[0050] During operation, air enters the air cleaner assembly 10 through the air inlet 18 . Air circulates between the housing side wall 24 and the main filter element 14 , and passes through the main filter element 14 and then through the safety filter element 16 , into the open interior 50 , and out of the air cleaner assembly via the air outlet 20 .
[0051] Now referring to FIGS. 13-22 , an alternative embodiment of an air cleaner assembly is shown at reference number 150 . The air cleaner assembly 150 can include a housing 152 , a main filter element 154 , and a safety liner 180 . The air cleaner assembly 150 provides for the filtering or cleaning of a variety of gases such as air for internal combustion engines.
[0052] The housing 152 includes an air inlet 158 and an air outlet 160 . The air inlet 158 can be characterized as a tangential air inlet 162 . The air outlet 160 can be characterized as an axial air outlet 163 . The housing 152 additionally can include an optional drop tube 164 and can include optional mounting legs 166 . The drop tube 164 can include an ejector valve 168 . The housing 152 includes a main housing 170 and a service cover 174 that attaches to the main housing 170 . The drop tube 164 and the ejector valve 168 can be provided as part of the service cover 174 or if desired, can be provided as part of the main housing 170 .
[0053] The air cleaner assembly 150 , as well as the housing 152 , can be characterized as having a first end 165 and a second end 167 . In general, the air outlet 160 can be characterized as extending through a housing end 169 at the first end 165 . In addition, the air inlet 158 can be characterized as being provided between the first end 165 and the second 167 , but can also be characterized as adjacent to the first end 165 in the embodiment shown in FIG. 13 . The service cover 174 , in the embodiment shown, can be characterized as attaching at the housing second end 167 .
[0054] The housing 152 includes a main housing 170 . The main housing 170 can be characterized as having a relatively cylindrical housing side wall 172 . The air cleaner housing 152 includes a service cover 174 that attaches to the main housing 170 . The service cover 174 can attach to the main housing 170 by latches 176 .
[0055] Now referring to FIGS. 14-16 , attachment of the safety liner 180 to the collar 182 is shown. The safety liner 180 includes bayonets 184 , and the collar 182 includes bayonet receivers 186 . The bayonets 184 slide within the bayonet receivers 186 to fit. The bayonet receivers include first side walls 188 and second side walls 190 . The first side walls 188 and the second side walls 190 hold the bayonets 184 in place. In addition, the bayonet receivers 186 can be molded in place. By way of example, the safety liner can include about 4 to about 8 bayonets and the collar can include about 4 to about 8 bayonet receivers to receive the bayonets.
[0056] The safety liner 180 additionally includes a support structure 192 for supporting the safety filter element 156 . In addition, the safety liner 180 includes a closed end cap 194 . The closed end cap 194 includes a central cone extension 196 , and a shoulder area 198 extending about the central cone extension 196 and between the central zone extension 196 and the closed end cap periphery 200 . The closed end cap periphery 200 generally refers to the annular edge region at the periphery of the closed end cap 194 .
[0057] The collar 182 includes an arm 201 , a collar extension 202 , a safety seal member 204 extending from collar extension 202 , and a radial seal member 206 extending from the collar extension 202 . A gasket or o-ring 208 can be provided to seal the collar 182 to the downstream end cap 169 of the housing 152 . The collar 182 can be snap fit onto the housing end 169 . The snap fit assembly is generally shown in FIGS. 14 and 16 .
[0058] Now referring to FIGS. 17-19 , placement of the safety filter element 156 on the support structure 192 is shown. The safety filter element 156 includes a safety seal member 212 , a safety end cap seal member 214 , and a safety media structure 216 . The safety media structure 216 can be provided similar to the safety media structure 68 . The safety media structure 216 can be provided having a layer of filtration media 218 and a layer of support structure 220 . The layer of filtration media 218 can, if desired, be pleated media.
[0059] The safety seal member 212 includes a lower seal member 222 and an upper seal member 224 . The safety seal member 212 engages the safety seal member 204 to provide a seal so that the lower seal member 222 and the upper seal member 224 provide compressive force on the safety seal member 204 . The safety seal member 204 can be referred to as the housing safety seal member because it is part of the housing. The safety seal member 212 can be referred as a pinch radial seal because the lower seal member 220 and the upper seal member 224 compress the safety seal member 204 . The safety seal member 212 can be made of polyurethane material.
[0060] The safety end cap seal member 214 includes a first extension arm 221 that engages the closed end cap 194 at a base 226 of the central cone extension 196 . The base 226 can be provided as part of the shoulder 198 . The base 226 helps seal, center, support, and guide the safety filter element 156 on the support structure, and avoid risk of collapsing. The safety end cap seal 214 includes a second extension arm 223 that extends axially along a length of the safety media structure 216 . The second extension arm 223 extends beyond the first extension arm 221 axially toward the apex 228 of the central cone extension 196 . The safety end cap seal member 214 can be provided as a polyurethane material. In addition, the structure of the safety end cap seal member 214 can provide a desirable guide for the safety media structure 216 during the molding process.
[0061] Now referring to FIGS. 20-24 , insertion of the main filter element 154 into the housing interior 230 is shown. The main filter element 154 includes a first open end cap 239 , a second closed end cap 242 , and a main filtration media 244 extending from the first open end cap 239 to the second closed end cap 242 . The first open end cap 239 includes a radial seal member 240 and an axial seal member 241 . The radial seal member 240 includes a radial seal surface 246 that engages the radial seal member 206 to create an annular, radial seal. The radial seal member 240 can be characterized as an outwardly directed radial seal because the direction of the seal is outward and toward the radial seal member 206 . The radial seal member 206 can be referred to as the housing radial seal member 206 , and the radial seal member 240 can be referred to as the main filter element radial seal member 240 . The axially seal member 241 is provided extending axially from the first open end cap 239 . The axially seal member 241 can be characterized as a molded-in-place lip type axially seal 243 . That is, the lip type axially seal can be provided so that it flexes when the main filter element is introduced into the housing. This allows the main filter element to absorb and tolerate the length of the main filter element while avoiding friction that can cause where between the main filter element and the service cover. The axially seal member 241 can be provided extending axially from the first open end cap 239 between the radial seal member 240 and the outer, peripheral 243 of the first open end cap 239 . Furthermore, the main filtration media 240 can be potted within the first end cap 239 and within the second closed end cap 242 . The first end cap 239 and the second end cap 242 can be made from polyurethane material.
[0062] The end cap 242 can be characterized as a closed end cap 250 . The end cap 242 includes an annular rim area 252 , a central bump 254 , and a recess 256 between the annular rim area 252 and the central bump 254 . The annular rim area 252 and the central bump 254 can be considered extending axially away from the first end 165 . Similarly, the recess 256 can be characterized as an area extending axially toward the first end 165 . In general, the annular rim area 252 contains the filtration media and extends cylindrically or conically. The central bump 254 is constructed to receive the central cone extension 196 when the main filter element 154 is fully inserted within the housing interior 230 . The recess 256 is constructed to engage the first extension arm 221 and provide contact between the recess 256 and the first extension arm 221 . This contact that can extend annularly or circumferentially can help hold the safety filter element 156 in place.
[0063] The annular rim area 252 includes an annular rim periphery 258 and can include a series of exterior slots 260 . The service cover 174 can be constructed to engage the slots 260 via bumps 280 on the service cover 174 to help hold the main filter element 154 in place to avoid rotation and vibration that might cause it to wear out.
[0064] The service cover 174 can be provided having an inner surface 282 that generally conforms to the closed end cap 250 . In general, the inner surface 282 can include a projection 284 that fits within the recess 256 , and can include a reverse cone 286 that receives the central bump 254 . Furthermore, the inner surface 282 can include an annular rim 288 that surrounds the main filter element 154 . The service cover 174 can be made of a plastic material and can be designed to guide, support, and push the safety element in place and participate to maintain the seal between the safety filter element 156 and the safety liner 180 .
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An air cleaner assembly, a main filter element, and a method for servicing an air cleaner assembly are provided according to the present invention. The air cleaner assembly includes an air cleaner housing and a main filter element. The air cleaner housing can include a safety liner or support having a closed end cap that supports the main filter element, and helps reduce the tendency of the main filter element to rotate during use of the air cleaner assembly.
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CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] This application is a Continuation-in-Part of U.S. application Ser. No. 10/724,583, filed Nov. 28, 2003 incorporated by reference in its entirety.
[0002] The present invention relates to the field of construction, especially construction of commercial and residential buildings. More specifically, this invention relates to safety devices for construction workers.
BACKGROUND
[0003] Workers face a variety of hazards on a construction site. Many of these dangers are well known, and a number of safety devices developed to alleviate them. The construction hard hat is perhaps the best known of these.
[0004] A somewhat lesser described hazard is that offered by small holes in the ground. These are often man-made during the construction of drains, electrical wiring, lighting systems, and the like. While these are rarely large enough for an adult to fall into, they do provide a tripping hazard. They are of particular concern to workers on ladders or high stools or walkers. These can easily we caught in a small hole and tip over, resulting in injury to the workers aboard the ladder or equivalent.
DESCRIPTION OF THE PRIOR ART
[0005] The present invention falls into the category of construction safety devices. There is a wealth of prior art in this area.
[0006] One relevant prior patent is U.S. Pat. No. 5,043,539, issued to inventor J. V. DeBartolo, Jr. on Aug. 27, 1991. His invention describes a knockout device for a wall.
[0007] Another relevant prior patent is U.S. Pat. No. 6,076,559, issued on Jun. 20, 2000 to inventor G. N. Castillo, describing a disposable protective cover for conventional plumbing fixtures during floor construction. However, this patent says nothing about being able to walk over it. In fact, it is shaped like a cup, and is designed to preserve a hole, not to cover it. As such, it is not a safety device.
[0008] D. D. Palmer is the inventor on yet another relevant prior patent, U.S. Pat. No. 5,507,501, which describes a sealing disc that is used in the pressure testing of a drain or vent in a plumbing system.
[0009] J. P. Lott et. al. are the inventors of U.S. Pat. No. 6,195,946, a patent that issued on Mar. 6, 2001. This patent describes concrete forms. In a similar patent, T. W. Meyers in U.S. Pat. No. 5,711,536 describes a seal for walls of poured concrete.
[0010] There is a need for a simple device that can protect construction workers from holes in the ground, particularly holes created by prior construction work. A protective device should be inexpensive yet durable, strong enough to bear the weight of a person walking thereon, and secure against forces (such as wind or running water) that may tend to move the device out of position.
SUMMARY OF THE INVENTION
[0011] The present invention consists of a strong rubber or plastic unibody with cap and stem that is sized to fit precisely into the opening of a man-made construction hole, and remain securely therein until removed.
[0012] It is an object of the present invention to provide a safe environment for construction workers, especially during early and middle stages of construction.
[0013] It is another object of the present invention to prevent people from inadvertently stepping into holes created in the process of construction, and thereby possibly suffering injury.
[0014] It is yet another object of this invention that workers on movable scaffolding be protected from moving said scaffolding into a hole, possibly tipping over and causing injury to workers.
[0015] It is a further object of the present invention to create a device that is clearly visible to people nearby, and warns them of a danger posed by a hole potentially in their path.
[0016] It is yet another object of this invention that the device is capable of remaining in place and in service until removed by workers utilizing the hole for construction, and thereby removing the hazard.
[0017] It is yet another object of this invention that the device is capable of keeping a construction hole clean and free of debris that might otherwise accumulate within said hole, and later interfere with subsequent construction activities.
[0018] It is yet another object of this invention that the device is suitably made of materials that are best utilized for durability and long life in construction service.
[0019] It is yet another object of this invention that the device be lightweight and inexpensive, yet strong and durable.
[0020] The foregoing objects of the invention, and other objects and advantages will become apparent from the detailed description of the preferred embodiment below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 displays from a side view a preferred embodiment of the current invention for use in circular (round) holes.
[0022] FIG. 2 shows the same preferred embodiment of the present invention from a top view.
[0023] FIG. 3 presents a side view of a second embodiment of the present invention in the manner of FIG. 1 . This embodiment is rectangular, for rectangular cutouts.
[0024] FIG. 4 shows the second embodiment of FIG. 3 from a top view, in the manner of FIG. 2 .
[0025] FIG. 5 displays a top view of the preferred embodiment after a warning label has been applied.
[0026] FIG. 6 shows the second embodiment of FIG. 3 from a top view, after a warning label has been applied.
[0027] FIG. 7 presents an application of the preferred embodiment to protect a drain site during construction of a residential bathroom.
[0028] FIG. 8 presents an application of the preferred embodiment to protect various drains and sites of floor lights during construction of a commercial building.
[0029] FIG. 9 presents an application of the preferred embodiment to protect a drain site during construction of a residential bathroom.
[0030] FIG. 10 displays yet another application of the preferred embodiment to protect coring holes for future installation of electrical panels in an industrial setting.
[0031] FIG. 11 displays still another application of the preferred embodiment on a residential kitchen site.
[0032] FIG. 12 displays yet another application of the preferred embodiment in an office or industrial bathroom site, again to protect drain holes.
[0033] FIG. 13 shows a couple of embodiments of the current invention from a side view, showing the top covers only.
[0034] In FIG. 14 is seen the current invention in place on a floor, either without (above) or with (below) sub-frame.
[0035] FIG. 15 illustrates a top view of another preferred embodiment of the present invention.
[0036] FIG. 16 is a bottom view of the embodiment of FIG. 15 .
[0037] FIG. 17 is a side view of the embodiment of FIG. 15 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0038] Detailed descriptions of the preferred embodiment are provided herein. It is to be understood, however, that the present invention may be embodied in various forms. Therefore, specific details disclosed herein are not to be interpreted as limiting, but rather as a basis for the claims and as representative basis for teaching one skilled in the art to employ the present invention in virtually any appropriately detailed system, structure or manner.
[0039] Referring to FIG. 1 , a preferred embodiment 100 of the current invention is shown in side profile. It is shown with a top cap 10 and underlying stem 15 . The stem is sized so as to fit closely in a construction drain hole, with different stem sizes corresponding to different drain sizes.
[0040] FIG. 2 shows the same preferred embodiment 100 of the current invention from a top plan view. Because the stem is sized to fit in the hole snugly, the top view completely obscures the hole.
[0041] In one preferred embodiment, the stem 15 will constitute a cylinder of 1 inch in diameter, appropriate for filing a 1-inch drain. The top cap 10 then will constitute a circle of about 1½ inches in diameter.
[0042] FIG. 3 is an alternate embodiment 200 of the current invention from a side plan view. The top cap 20 and the stem 25 are displayed.
[0043] FIG. 4 is a top plan view of the same embodiment 200 of the current invention as displayed in FIG. 3 . From this view it can be seen that this embodiment is rectangular in shape. This is to correspond with rectangular cutout holes, as commonly used to install electrical switches and other components.
[0044] In FIG. 5 , a view from the top is displayed of the preferred embodiment of the current invention in an example where a warning label 17 has been applied. The warning label consists of yellow lettering in black outline, with alternating black and yellow stripes.
[0045] The same view with a warning label 27 is displayed of the alternate rectangular configuration of the present invention in FIG. 6 .
[0046] FIG. 7 shows an environment where the present invention could be employed. This is a residential bathroom under construction, with open drain hole 18 . This could be protected with the preferred embodiment of FIG. 1 until the drain cover is installed.
[0047] FIG. 8 shows another environment where the present invention could be employed. This is a courtyard area under construction, with open drain holes 18 and holes 19 for floor lighting. These could be protected with the preferred embodiment of FIG. 1 until the drain covers and lights are installed.
[0048] FIG. 9 displays yet another environment where the rectangular embodiment of the present invention could be employed. This is an office area under construction, with open holes 28 for floor installation of electrical wiring for office equipment such as desktop workstations, lighting, and the like.
[0049] FIG. 10 illustrates still another environment where the present invention could be employed. This is an electrical under construction, with open coring holes 14 for floor installation of heavy-duty electrical wiring. These holes could be protected with the preferred embodiment of FIG. 1 until the electrical wiring is installed.
[0050] FIG. 11 depicts still another environment where the present invention could be employed to protect open drain holes 18 until covered in subsequent construction. Likewise,
[0051] FIG. 12 illustrates an industrial area with open drain holes 18 , suitable for protection by installing the present invention.
[0052] FIG. 13 illustrates selected styles of top caps that could be employed with the present invention. Different curves of the edges, and height of the cap are envisioned. However, in general the cap will be no more than ¼ inch in thickness. This is to avoid presenting a tripping hazard.
[0053] FIG. 14 depicts the present invention 100 in place in a hole in a floor. The invention is seen from a cutaway side view. FIG. 14 a shows a floor with frame and underframe forming the two lower layers, with the cap of the present invention forming the top layer. FIG. 14 b shows the same view, in a floor without underframe. In this case, the frame forms the lower layer, with the cap of the present invention forming the top layer.
[0054] FIGS. 15-17 illustrate another embodiment of the present invention having a cover 300 formed with a solid, convex upper surface 305 and a generally smooth, flat lower surface 310 . The upper surface 305 may include a hot stamped cautionary indicia 315 imprinted thereon, such as the words “CAUTION” and “DO NOT REMOVE.” The cover 300 is integrally formed with an annular stem 320 with an inner surface 325 and an outer surface 330 . The outer surface 330 is preferably formed with longitudinally extending elongate ribs 335 spaced apart by regular angular intervals such as ninety degrees. The ribs 335 extend from the cover's flat lower surface 310 to a position beyond the midpoint of the stem 320 , and more preferably about three quarters of the distance of the stem. The ribs 335 prevent jamming of the device in close-fit holes while providing a better fit for holes with higher tolerances. The ribs also help to strengthen the stem and provide additional stiffness. In a preferred embodiment the ribs 335 are trapezoidal in cross-section to further increase the stiffness. The ribs 335 can number anywhere from two to eight or more, but a preferred embodiment includes four equally spaced apart ribs. In a preferred embodiment, the lower surface of the cover 340 that lies inside the stem 320 is arched to reduce materials, but includes reinforcing members 345 to increase the loading capability of the device. The reinforcing members 345 can extend across the walls of the stem 320 in a grid pattern to provide resistance to collapse of the arch forming the cover 300 . In a preferred embodiment, the hatch pattern is formed by two parallel members intersecting two transverse members to form a square 350 in the middle of the lower surface 340 . The reinforcing members contribute to the present invention's sturdiness and resistance to compression in compliance with many federal and state regulations. The present invention in the three inch diameter and four inch diameter are capable of withstanding five thousand pounds of load without failure (i.e., suffering permanent deformation).
[0055] The present invention is made of sturdy materials, such as hard engineering polyethylene, to withstand the weight of heavy construction workers walking or standing on it. In a preferred embodiment, the invention is made of 1-propene, polymer with ethene percent by weight greater than 98. The device is preferably bright yellow to ensure high visibility in construction environments, where indicia is colored black to establish a high contrast and improve the cautionary function. The invention is designed to meet all OSHA requirements for safety.
[0056] The stem is sized, both in horizontal and vertical dimensions, to fit snugly in the construction holes. Such precise fitting is important to maintaining the structural integrity of the device, and to allow the device to remain stably within the hole. The device is positioned without screws or fasteners, but rather is gravitationally positioned and is easily removed.
[0057] It should be recognized that holes made for construction purposes are well defined in dimensions, and limited in variability and number of different sizes. Thus, it is feasible to produce the present invention in a limited number of sizes and dimensions, to conform to said limited sizes and dimensions of construction holes.
[0058] Installation of the present invention is very straightforward. It is simply a matter of selecting the appropriate size and shape of the embodiment that best fits the hole to be protected. The embodiment is then place in the hole with top cover facing up, and thus displaying the optional warning label. The device is left in place until removed by later construction workers, at the time the hole is to be utilized.
[0059] The device is designed to be reusable, and potentially recyclable if damaged during use.
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The present invention is construction safety device designed for use on construction sites where man-made holes are present. The new safety device is constructed of high-impact resistant polyethylene, and is highly durable. The device is sized to fit snugly in construction holes, and can be walked on. It protects workers from hazards presented by holes, and keeps the holes clear of debris.
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TECHNICAL FIELD
[0001] The present invention relates to discharge method, local ventilation method, discharger, local ventilator, and ventilation system, and more particularly to an effective technology of discharge and local ventilation for use in any indoor space requiring discharge and ventilation such as factory, kitchen, smoking room, and toilet, where sources of contaminants causing polluted air can be specified in a specific area in the room, and polluted air is not seriously harmful for human health such as hot air flow, steam, odor, cigarette smoke, oil fume or dusty air.
BACKGROUND ART
[0002] Generally in indoor space having sources of contaminants causing polluted air such as factory, kitchen, smoking room, and toilet, discharge or ventilation for cleaning the indoor atmosphere is needed.
[0003] In this case, if the polluted air is not seriously harmful for human health such as hot air flow, steam, odor, cigarette smoke, oil fume or dusty air, local ventilation method for such indoor space is generally an overall ventilation method for exchanging the entire air of the room, in a diluted state of polluted air mixed in the indoor atmosphere.
[0004] Overall ventilation method consists of three types, that is, a case of using mechanical power in both intake and discharge, a case of using mechanical power in intake and discharging naturally through suction opening, and a case of using mechanical power in discharge, and sucking naturally from intake opening, and the mainstream is the mechanical intake and discharge method.
[0005] According to statutory regulations about ventilation in general buildings, ventilation rates are roughly determined for the purposes of assuring safety and sanitation of people as calculated from the allowable carbon dioxide concentration in the room, or keeping necessary amount of oxygen for combustion in a room using fire or flame, and standards based on pure technology or performance are not clear. In the present building technical field or industries, it has been a general trend not to spend too much money in ventilation system as far as the statutory requirements about ventilation are satisfied.
[0006] On the other hand, a general ventilation system in a room demanding a certain habitability and working efficiency, for example, a professional kitchen ventilation system is composed, for example, in an overall ventilation system, as shown in FIG. 19 , in which a combustion heating cooking device (a) as source of contaminant is disposed closely to the wall of the room, and the entire air of the kitchen is ventilated.
[0007] That is, in the ceiling above the cooking device (a), a suction opening (c) is opened for a discharge duct (b), and discharge fan for duct (not shown) is provided at the outdoor side end of the discharge duct (b). The suction opening (c) is covered with a discharge hood (e) for capturing polluted air containing hot jet flow (d) of contaminants generated by combustion and heating of the cooking device (a), and diffusion of polluted air is prevented. On the other hand, in the ceiling of the central part of the room away from the cooking device (a), a discharge opening (h) of intake dust (g) having intake box (f) is opened, and an air conditioner (i) is installed. In the ceiling near an opening (m) remote from the cooking device (a), a discharge duct (k) having a ceiling discharge fan (j) is opened.
[0008] The hot jet flow (d) of contaminants generated by combustion and heating of the cooking device (a) is captured into the discharge duct (b) from the discharge hood (e) and suction opening (c) by driving of dust discharge fan of the discharge duct (b), and is discharged out of the room, and the indoor air at a position remote from the cooking device (a) is discharged out of the room (not shown) through discharge duct (k) opened near the opening (m). On the other hand, from the intake opening (h) in the center of the ceiling, by driving of dust intake fan (not shown), fresh outdoor air is supplied through intake box (f) of intake duct (g), and also fresh air flows in from the window (m) of the kitchen. As a result, the entire air in the kitchen is ventilated.
[0009] However, such conventional overall ventilation method has the following problems, and it has been desired to solve them.
[0010] As represented by kitchen, when the overall ventilation system is installed in a room having many sources of contaminants, the ventilation rate is enormous and discharge efficiency is poor in ventilation, and since a huge volume of fresh air is introduced as intake, the indoor air becomes same as outdoor air.
[0011] Discharge by suction and discharge stream by using mechanical power is poor in controllability, and only the contaminants cannot be discharged effectively, and heat, steam, oil fuse, odor or vapor may be stagnant in the room, and the indoor air conditioning state is poor.
[0012] For example, in the case of kitchen, to satisfy the temperature and humidity condition of the kitchen as the standard of hazard analysis and critical control point (HACCP), a tremendous amount is required in ventilation air flow and air conditioning capacity.
[0013] Increase of ventilation air flow and air conditioning capacity leads to increase of ventilation and air conditioning equipment capacity, and also increase in initial cost and running cost of ventilation and air conditioning equipment.
[0014] In addition, increase of ventilation and air conditioning equipment capacity also leads to increase of electric capacity of equipment, and such increase of energy consumption also causes to increase outputs of global warming gases such as CO and CO 2 .
[0015] Concerning this point, the following ventilation system of special application may be used in ventilation system in a room requiring specific habitability and working efficiency as ventilation system of kitchen.
[0016] That is, in factory ventilation, since substances harmful for human health are released, statutory standards are strict, and sources of harmful contaminants are enclosed by partitions, and the operator puts hands into the partitions, and the partial or local ventilation system by draft chamber is widely employed as effective means.
[0017] If the draft chamber cannot be used depending on the kind of work, the so-called push-pull flow method is executed as effective local ventilation system. In local ventilation system by push-pull flow method, sources of contaminants are enclosed by uniform flow of blowing (push) flow and sucking (pull) flow, and air balance is completed locally.
[0018] Overall ventilation system for ventilating a wide space such as indoor parking facility includes so-called delivent ventilation system making use of induction action. In this delivent ventilation system, corresponding to suction discharge, indoor polluted air is guided and delivered to the suction opening by plural small blowers arranged sequentially, and by this method of ventilation, the duct extension distance can be shortened, and efficient ventilation is realized.
[0019] However, even in such local ventilation system or overall ventilation system effective in special applications, when employed as ventilation system of a room requiring a certain habitability or working efficiency, there are new problems as listed below, it is far from the level of actual execution.
[0020] That is, in the local ventilation method by draft chamber, since the sources of contaminants are enclosed by partitions, there is no risk of leak of polluted air into the room, but materials cannot be delivered onto the working surface through the door, the working efficiency is extremely poor.
[0021] In the local ventilation method by push-pull flow type, contaminant sources are enclosed, and the air flow rate of induction stream and suction discharge stream is balanced in the entire surrounding space, and hence when the bore of the blow opening and the core of suction opening become large, the air flow rate increases tremendously. From the viewpoint of working efficiency, the worker gets into the uniform air flow, and in the case of kitchen, a lower blow opening is provided, different from the upper suction opening, and not only the working efficiency is lowered, but there is also problem of sanitation.
[0022] The ventilation method by delivent ventilation system is overall ventilation method, not local ventilation, and assuming automotive emission to be collected in the ceiling of indoor parking facility, it is intended to guide in the discharge direction, and the discharge efficiency is enhanced, but the air flow rate is not decreased. Besides, since many small delivent fans are installed in the ceiling, the noise is very large.
[0023] In this regard, the present applicant has previously developed and proposed a local ventilation system as disclosed in Japanese Patent Publication No. 2001-355889. This local ventilation system, as shown in FIG. 20 , mainly comprises a discharge device (p) composed of suction discharge stream generator (q) and blow induction flow generator (r).
[0024] The suction discharge stream generator (q) has a suction opening (t) in the ceiling above contaminant source (s) such as cooking device, and is designed to cause an upward suction discharge stream (v) consecutive to outdoor air by discharge fan (u). On the other hand, the induction flow generator (r) has a blow opening (w) at position near the side of the contaminant source (s), and is designed to generate upward blow induction stream (y) by blow fan (x). The blow opening (w) is provided at a position not interfering with the working range of the worker M.
[0025] By driving of discharge fan (u), upward suction discharge stream (v) consecutive from suction opening (t) at the upward position of contaminant source (s) to outdoor air is generated, and by driving of blow fan (x), upward blow induction stream (y) is generated from the blow opening (w) of the blow nozzle near the side of the contaminant source (s), and by the induction action of this blow induction stream (y), the polluted area near the surrounding of contaminant source (s) is collected and distributed by force into the suction exhaust flow (v).
[0026] By this local ventilation system, ventilation can be completed locally without sacrificing the habitability and working efficiency.
[0027] The invention is intended to improve further this local ventilation system, and to present a new technology of discharge and local ventilation capable of decreasing the ventilation rate and air conditioning capacity substantially, and eliminating consumption of electric energy and decreasing the device capacity, by decreasing the air conditioning load by introduction of fresh air by air intake.
[0028] It is other object of the invention to present technology of discharge ad local ventilation having an allowance in existing power source capacity and air conditioning capacity, and capable of effectively utilizing the existing ducts and other installations, by decreasing the ventilation rate and air conditioning capacity substantially.
DISCLOSURE OF THE INVENTION
[0029] To achieve these objects, the discharge method of the invention is a discharge method of discharging polluted air around and near a contaminant source in a room having the contaminant source to cause polluted air, comprising the steps of generating upward suction discharge stream from upward position of the contaminant source to outdoor air, generating upward blow induction stream from the position near the side of the contaminant source to the upward suction discharge stream, and by induction action of the blow induction stream, taking up the polluted area near the surrounding of the contaminant source and collecting and delivering by force into the upward suction discharge stream.
[0030] In a preferred embodiment, the blow induction stream is set so as to blow outward the suction opening inside of the suction discharge stream, and the suction opening is disposed and formed so as to overlap almost entirely with the contaminant source in a plan view. The blow induction stream is formed by indoor air or outdoor air.
[0031] A first local ventilation method of the invention is a method of locally ventilating a room having a contaminant source to cause polluted air, being characterized by applying the above discharge method on the contaminant source, and supplying a specified amount of intake air from a proper position, and thereby establishing balance of room air and local air simultaneously.
[0032] A second local ventilation method of the invention is a method of locally ventilating a room having a contaminant source to cause polluted air, being characterized by applying the above discharge method on the contaminant source, generating downward blow intake stream from the surrounding position of suction discharge opening, and pushing back the polluted air leaking out of the discharge region of suction opening by force into the suction opening again by the air curtain action of the blow intake stream.
[0033] In both local ventilation methods, preferably, the air flow rate of the suction discharge stream can be set depending on the sum value of the air flow rate of blow induction stream, polluted air flow around the contaminant source guided by this blow induction stream, and air flow amount, thereby establishing balance of room air and local air simultaneously.
[0034] The discharger of the invention is intended to execute the discharge method above, comprising suction discharge stream generating means for generating an upward suction discharge stream consecutive to outdoor room, having a suction opening opened in an upward position of the contaminant source, and blow induction stream generating means for generating an upward blow induction stream, having a blow opening provided near the side of the contaminant source, in which the blow induction stream generating means is set to blow out the blow induction stream from the blow opening to the inside of suction opening, and by the induction action of the blow induction stream by the blow induction stream generating means, the polluted air around the contaminant source is taken up, and collected and delivered by force to the suction discharge stream.
[0035] In a preferred embodiment, the discharge duct of suction discharge stream generating means has its end opened to outdoor side, and its base end communicates with a discharge box formed as a box container, and the suction opening is opened oppositely to this discharge box in the room. In this case, in the discharge box, preferably, the axial direction of the connection opening connected to the base end of the discharge duct should intersect in the axial direction of the suction opening. Air source of blow induction stream generating means is either indoor air or outdoor air.
[0036] The suction opining is disposed and formed so as to overlap almost entirely with the contaminant source in a plan view.
[0037] On the outer circumference of the suction opening, a discharge hood is provided for preventing diffusion of blow induction stream from the blow induction stream generating means and taken-up stream of polluted air guided by this induction stream, and the inner peripheral wall of the discharge hood is preferred to be a sloped wall climbing upward to the suction opening.
[0038] A first local ventilator of the invention is a device of locally ventilating around a contaminant source in a room having a contaminant source to cause polluted air, is being characterized by installing the discharger on the contaminant source, and supplying a specified amount of intake air from a proper position, and thereby establishing balance of room air and local air simultaneously.
[0039] A second local ventilator of the invention is a device of locally ventilating around a contaminant source in a room having a contaminant source to cause polluted air, being characterized by installing the discharger on the contaminant source, having intake means for generating downward blow intake stream from the surrounding position of suction discharge opening, and pushing back the polluted air leaking out of the discharge region of suction opening by force into the suction opening again by the air curtain action of the blow intake stream of the intake means.
[0040] In both local ventilators, preferably, the suction air flow rate of the suction discharge stream generating means is set depending on the sum value of the blow air flow rate of blow induction stream generating means, blow air flow rate of the intake means, and polluted air flow rate around the contaminant source guided by the blow induction stream of the blow induction stream generating means, thereby establishing balance of room air and local air simultaneously.
[0041] Preferably, it further comprises intake means for generating downward blow intake stream from around the suction opening of the discharge stream generating means, and by the air curtain action of the blow intake stream of this intake means, polluted air leaking to outside of the suction opening is pushed back by force into the suction opening again. In this case, the blow opening of the intake means is preferably provided integrally on the outer circumference of the discharge hood provided on the outer circumference of the suction opening, and further the blow opening of the intake means is provided at a position of ceiling level on which the discharge hood is mounted.
[0042] Preferably, the suction air flow rate of the suction exhaust stream generating means is set depending on the sum value of the blow air flow rate of blow induction stream generating means, blow air flow rate of the intake means, and polluted air flow rate around the contaminant source guided by the blow induction stream of the blow induction stream generating means, thereby establishing balance of room air and local air simultaneously.
[0043] The ventilation system of the invention is composed by installing the local discharger on the contamination source, in a room having a contaminant source to cause polluted air, and establishing the balance of indoor air and local air simultaneously. In this case, it further comprises supplement ventilation means for compensating for ventilation rate in the room, and it is driven manually or automatically by carbon dioxide sensor or the like when becoming lower than a specified ventilation rate, thereby establishing the balance of indoor air and local air simultaneously.
[0044] In the invention, by the suction discharge stream and blow induction stream, an upward uniform stream of high controllability is formed to pass near the surrounding of contamination source to cause polluted air, and by the induction action of blow induction stream, the polluted air around the contaminant source is collected and delivered by force into the suction discharge stream. In other words, the stream of air from around the contaminant source toward the suction opening of the suction discharge steam is created by force in the room, and this stream of air takes up the polluted air, and brings out to the suction opening of the suction discharge stream.
[0045] Thus, the upward uniform stream for discharging the polluted by force is discharged without enveloping the contaminant source by passing around and near the contaminant source, there is almost no interference with the workers and working operation, and habitability and working efficiency are not spoiled.
[0046] By completing ventilation locally by discharge, the ventilation rate and air conditioning capacity can be saved, and by keeping low the capacity of ventilation and air conditioning equipment, the initial cost and running costs of the ventilation and air conditioning equipment can be saved, and by reduction of consumption of electric energy, generation of global warming gases can be cut low.
[0047] As a result of substantial reduction of ventilation rate and air conditioning capacity, a sufficient allowance is made in the existing power source capacity and air conditioning capacity, and the existing ducts and other ventilation facilities can be directly used effectively.
[0048] The leading ends of ventilation ducts of suction discharge stream generating means are opened to outdoor side, and the base end communicates with the discharge box formed as a box container, and suction opening of the suction discharge stream is opened against this discharge box in the room, so that the suction opening may be disposed freely within the discharge surface side range of the discharge box, and the degree of freedom of layout is increased in the contamination source, such as cooking apparatus, and the existing ducts can be directly used effectively.
BRIEF DESCRIPTION OF THE DRAWINGS
[0049] FIG. 1 is a front view of local ventilator in embodiment 1 of the invention.
[0050] FIG. 2 is a plan view of the local ventilator.
[0051] FIG. 3 is a sectional view along line A-A or line B-B in FIG. 2 showing the local ventilator.
[0052] FIG. 4 is a sectional view along line C-C in FIG. 2 showing the local ventilator.
[0053] FIG. 5 is a plan view of suction discharge stream generating unit and intake device of the local ventilator.
[0054] FIG. 6 is a plan view of configuration of blow induction stream generating unit of the local ventilator showing in relation to combustion heating type cooking apparatus.
[0055] FIG. 7 is a front view of local ventilator in embodiment 2 of the invention.
[0056] FIG. 8 is a front view of local ventilator in embodiment 3 of the invention.
[0057] FIG. 9 is a front view of local ventilator in embodiment 4 of the invention.
[0058] FIG. 10 is a side view of local ventilator in embodiment 5 of the invention.
[0059] FIG. 11 shows discharge stream generating unit and intake device of the local ventilator, FIG. 11A is a plan view, FIG. 11B is a front view, and FIG. 11C is a bottom view.
[0060] FIG. 12 shows blow induction stream generating unit of the local ventilator, FIG. 12A is a plan view, and FIG. 12B is a front view.
[0061] FIG. 13 shows blow induction stream generating unit of local ventilator in embodiment 6 of the invention, FIG. 13A is a plan view, FIG. 13B is a front view, and FIG. 13C is a side view.
[0062] FIG. 14 shows blow induction stream generating unit of local ventilator in embodiment 7 of the invention, FIG. 14A is a plan view, FIG. 14B is a front view, and FIG. 14C is a side view.
[0063] FIG. 15 shows blow induction stream generating unit of local ventilator in embodiment 8 of the invention, FIG. 15A is a plan view, FIG. 15B is a front view, and FIG. 15C is a side view.
[0064] FIG. 16 is a plan view of smoking room having local ventilator in embodiment 9 of the invention installed as smoke separator.
[0065] FIG. 17 is a front view from arrow direction of line A-A in FIG. 16 showing the structure of the smoking room.
[0066] FIG. 18 is a side view from arrow direction of line B-B in FIG. 16 showing the structure of the smoking room.
[0067] FIG. 19 is a front view of local ventilator in embodiment 10 of the invention.
[0068] FIG. 20 is a sectional view corresponding to FIG. 3 showing the local ventilator.
[0069] FIG. 21 is a sectional view corresponding to FIG. 4 showing the local ventilator.
[0070] FIG. 22 is a block diagram of ventilation system in a conventional kitchen.
[0071] FIG. 23 is a block diagram of local ventilator in other conventional kitchen.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0072] Referring now to the drawings, preferred embodiments of the invention are described below.
Embodiment 1
[0073] A local ventilator of the invention is shown in FIG. 1 and FIG. 2 . The local ventilator PV is an apparatus for ventilating locally around the contaminant source in a room having a contaminant source to cause polluted air, and specifically it is for a professional kitchen use in a school, hospital or relatively large building in a room depending specific habitability and working efficiency.
[0074] The local ventilator PV has a discharger E for combustion heating type cooking device 1 such as table cooking range as source of contaminant, and intake device (intake means) S is integrally provided in the discharger E.
[0075] The discharger E mainly consists of suction discharge stream generator (suction discharge stream generating means) 2 , and blow induction stream generator (blow induction stream generating means) 3 .
[0076] The suction discharge stream generator 2 has a suction opening 5 provided above the cooking device 1 , and is designed to generate an upward suction discharge stream 6 consecutive to the outdoor side. This suction discharge stream 6 mainly function as a stream of discharging by sucking the polluted air of the contaminant released from the cooking device 1 .
[0077] The suction discharge stream generator 2 is specifically provided in the ceiling above the cooking device 1 , and a leading end 10 a of a discharge duct 10 is opened to outdoor side, and its base end 10 b communicates with a discharge box 11 , and the suction opening 5 is opened in the discharge box 11 oppositely in the room. A discharge fan 12 as discharge stream generating source is provided at the leading end 10 a of the discharge duct 10 .
[0078] The discharge box 11 is intended to have a degree of freedom of opening of the suction opening 5 at the indoor side opening of the discharge duct 10 , and it is formed like a box container.
[0079] In the discharge box of the preferred embodiment, as shown in FIG. 2 and FIG. 5 , three rectangular suction openings 5 a , 5 b , and 5 c are provided in the rectangular bottom. The suction openings 5 a , 5 b , 5 c are, as shown in FIG. 2 , disposed and formed so as to overlap almost entirely with the combustion heating type cooking device 1 in the room, and are installed so that the capturing area may be as wide as possible.
[0080] Specifically, the first suction opening 5 a is disposed at a position nearly above the first table cooking range 1 a of the combustion heating type cooking device 1 , and is formed in a shape to cover the table cooking range 1 a as much as possible. The second and third suction openings 5 b and 5 c are provided closely above the second to fourth table cooking ranges 1 b to 1 d of the combustion heating type cooking device 1 , and formed in a shape to cover the table cooking ranges 1 b to 1 d as much as possible.
[0081] In the discharge box 11 , the axial direction of connection opening for connecting the base end 10 b of the discharge duct 10 , that is, the duct connection direction X, and the axial direction of the suction opening 5 , that is, the suction opening discharge stream direction Y are arranged to intersect with each other, so that the air stream is dispersed.
[0082] In the illustrated preferred embodiment, the discharge box 11 is rectangular parallelepiped, and two discharge ducts 10 , 10 are connected to its one vertical side, the three suction openings 5 a to 5 c are opened in the horizontal bottom, and the intersecting angles of duct connection directions X, X and suction opening discharge stream directions Y, Y, . . . are right angles.
[0083] Inside the discharge box 11 , grease remover (grease removing means) 13 is provided for separating and removing oily contents in the discharge. This grease remover 13 is specifically a grease filter, and is provided in the discharge box 11 , between the suction openings 5 ( 5 a to 5 c ) and connection openings of discharge ducts 10 , 10 . In such configuration, when the blow induction stream is blown out toward the suction openings 5 ( 5 a to 5 c ), it is effectively prevented from colliding against the grease remover 13 to scatter about to become turbulent flow.
[0084] In the indoor side outer circumference of the suction openings 5 ( 5 a to 5 c ), a discharge hood 15 is provided. This discharge hood 15 is intended to supplement the structure and action of the blow induction stream generator 3 . That is, the discharge hood 15 prevents diffusion of blow induction stream from the blow induction stream generator 3 , and take-up flow of polluted air guided into the blow induction stream, and these discharge streams are securely captured and the discharge effect is enhanced.
[0085] In the discharge hood 15 of the illustrated preferred embodiment, its inner peripheral wall 15 a is formed in a sloped wall climbing up toward the suction openings 5 ( 5 a to 5 c ). That is, as mentioned above, the capturing area of suction openings 5 ( 5 a to 5 c ) is wide, but in order that the suction opening area should not be excessive, the inner peripheral wall 15 a of the discharge hood 15 is formed as a sloped wall climbing up from the lower end to the suction openings 5 ( 5 a to 5 c ), specifically to the bottom 11 a of the discharge box 11 , so that bouncing of polluted air is suppressed.
[0086] The blow induction stream generator 3 is intended to collect and deliver the polluted air around the combustion heating type cooking device 1 by force into the suction discharge stream 6 , and a blow opening 20 is provided near the side of the cooking device 1 , and an upward blow induction stream 21 is generated.
[0087] Specifically, the blow induction stream 21 from the blow opening 20 is designed to blow out into the inside of the suction opening 5 , and the majority of the blow induction stream 21 is engulfed into the suction discharge stream 6 . In other words, the blow induction stream 21 is prevented from colliding against the periphery of the suction opening 5 to scatter about to form turbulent flow.
[0088] The blow induction stream generator 3 of the illustrated preferred embodiment has three induction stream generating devices 22 a , 22 b , 22 c corresponding to first to fourth table cooking ranges 1 a to 1 d of the combustion heating type cooking device 1 as shown in FIG. 6 . The location of these induction stream generating devices 22 a , 22 b , 22 c is arranged so as not to interfere with the working area of the workers (cooks, not shown), that is, the outer periphery of the combustion heating type cooking device 1 in FIG. 6 .
[0089] Specifically, the first induction stream generating device 22 a is provided in contact with the back side of the first table cooking range 1 a of the combustion heating type cooking device 1 , the second induction stream generating device 22 b is provided between the second table cooking range 1 b and fourth table cooking range 1 d , and the third induction stream generating device 22 c is provided between the third table cooking range 1 c and fourth table cooking range 1 d.
[0090] These induction stream generating devices 22 a , 22 b , 22 c are basically same in structure, and are installed in upright position on the casing of the combustion heating type cooking device 1 , that is, on the cooking table 25 .
[0091] More specifically, the induction stream generating devices 22 a , 22 b , 22 c are arranged as shown in FIG. 1 , FIG. 3 , and FIG. 4 , in which the top of the device main body 26 of hollow long box shape coincides with a blow nozzle 28 of the blow opening 20 , and blow fans 27 , 27 as induction stream generating sources are provided in the lower part of the device main body 26 in horizontal position, and the air source is indoor air.
[0092] An intermediate tubular portion 26 a of the device main body 26 functions as straightening section for straightening the induction stream sent into the blow nozzle 28 from the blow fans 27 , 27 .
[0093] Each blow nozzle 28 is composed so that its axial line may be extended toward the inside of the suction openings 5 ( 5 a to 5 c ) of the exhaust box 11 . That is, the blow nozzle 28 of the first induction stream generating device 22 a has its axial line in inclined and upright position to pass through nearly the center of the first suction opening 5 a as shown in FIG. 4 , and the blow induction stream 21 is blown obliquely upward toward the inside of the suction opening 5 a from the blow opening 20 , while the blow nozzles 28 , 28 of the second and third induction stream generating devices 22 b , 22 c are have their axial lines in vertical and upright position to pass through nearly the center of the second and third suction openings 5 b , 5 c as shown in FIG. 3 , and the blow induction stream 21 is blown upward vertically toward the inside of the suction openings 5 b , 5 c from the blow opening 20 .
[0094] In the discharger E having such configuration, by driving of discharge fans 12 , 12 of suction discharge stream generator 2 , upward suction discharge streams 6 , 6 , 6 consecutive to the suction openings 5 ( 5 a to 5 c ) are generated, and by driving of blow fans 27 , 27 , . . . of the blow induction stream generator 3 , upward blow induction streams 21 , 21 , 21 straightly extending to the suction openings 5 ( 5 a to 5 c ) from the blow opening 20 of the blow nozzles 22 in the induction stream generators 22 a , 22 b , 22 c are generated.
[0095] As a result, the upward uniform stream by these streams 6 , 21 (an always uniform stream, not changing from time to time, in the state of stream at a certain stream section) is formed to pass around the combustion heating type cooking device 1 , and by the attracting action of blow induction streams 21 , 21 , 21 by the blow induction stream generator 3 , the polluted air around the combustion heating cooking device 1 including the hot jet flow o contaminants generated from combustion heat of the combustion heating type cooking device 1 is collected and delivered by force into the suction discharge stream 6 .
[0096] In other words, a stream of air from around the combustion heating type cooking device 1 toward the suction openings 5 ( 5 a to 5 c ) of the suction discharge stream 6 is produced by force in the room, and this stream of air entraps the polluted air, and runs into the suction openings 5 ( 5 a to 5 c ) of the suction discharge stream 6 . To reinforce the attracting action of the suction induction stream 21 , preferably, the air flow rate of the suction induction stream 21 should be determined appropriately, so that the polluted air staying beneath the ceiling 45 without being sucked into the suction openings 5 ( 5 a to 5 c ) by inductive or attracting action of blow induction stream 21 may be promptly sucked into the suction openings 5 ( 5 a to 5 c ), that is, into the discharge box 11 , before being diffused into the air due to effects of stream generated in the room by air conditioner or other cause.
[0097] The actual section of this air stream (stream section) is a combination of uniform straight flow and vortex (entrapped flow) toward the suction openings 5 ( 5 a to 5 c ), and the composed stream is basically a straight flow, but instead of turbulent flow, a swirl flow (entrapped flow) almost having no change in time series is included.
[0098] The polluted air thus brought into the suction discharge stream 6 is discharged out of the room, together with this suction discharge stream 6 , by way of discharge box 11 and discharge duct 10 .
[0099] At this time, the oily content of the suction discharge stream 6 including the polluted air is separated and removed by the grease remover 13 in the discharge box 11 , and since this grease remover 13 is disposed in the discharge box 11 , the blow induction streams 21 , 21 , 21 do not collide against the grease remover 13 to scatter about to form turbulent flow, so that a smooth induction discharge effect is assured.
[0100] The intake device S disposed integrally with the discharger E and forming a principal component of the local ventilator PV is designed to generate downward intake stream 30 from the surrounding positions of the suction openings 5 ( 5 a to 5 c ) of the suction discharge stream generator 2 .
[0101] The intake device S has its intake opening 35 formed integrally with the discharge hood 15 , and in other words the discharge hood 15 is formed as an integral intake-discharge hood.
[0102] In the specific structure of the intake device S, a base end 40 a of an intake duct 40 is opened to the outdoor side, and its leading end 40 b communicates with an intake box 41 formed integrally on the outer circumference of the discharge hood 15 , and the intake opening 35 is opened oppositely to the intake box 41 in the room. An intake fan 42 as intake stream source is provided at the base end 40 a of the intake duct 40 .
[0103] The intake box 41 is a box container of rectangular annular form surrounding the entire periphery of the discharge hood 15 .
[0104] In the intake box 41 of the illustrated preferred embodiment, two intake ducts 40 , 40 are connected, and as shown in FIG. 2 and FIG. 5 , the intake opening 35 is provided to extend around the whole peripheral wall of the rectangular annular form.
[0105] Same as in the case of the discharge box 11 , as shown in FIG. 1 , the axial direction of connection opening of intake box 41 for connecting the leading ends 40 b , 40 b of intake ducts 40 , 40 , that is, the duct connection direction X 1 , and the axial direction of the intake opening 35 , that is, the intake opening intake stream direction Y 1 are arranged to intersect with each other, so that the stream is dispersed.
[0106] The intake opening 35 is, as shown in FIG. 1 to FIG. 5 , opened along the outer contour of the lower edge of the discharge hood 15 , and is disposed to surround the whole periphery of combustion heating cooking device 1 and blow induction stream generator 3 in the room, and as described below, by the air curtain action of the blow intake stream 30 from the intake opening 35 , overflow of polluted air outside of the discharge region of suction opening 5 can be effectively prevented.
[0107] The bottom of the intake box 41 having the intake opening 35 is set at the same level as the ceiling 45 mounting the discharge hood 15 as shown in FIG. 1 , FIG. 3 and FIG. 4 . In such structure, the blow intake stream 30 like air curtain from the intake opening 35 functions to prevent overflow of polluted air to outside from the discharge hood 15 as mentioned above, and also functions to prevent formation of temperature layer by agitating the indoor air, thereby keeping uniform the room temperature.
[0108] In the intake device S having such configuration, by driving of intake fans 42 , 42 , a downward blow intake stream 30 is generated like air curtain from the annular intake opening 35 at the level of the ceiling 45 , and by the air curtain action of the blow intake stream 30 , the polluted air leaking out of the discharge region of the suction openings 5 ( 5 a to 5 b ) of the discharger E is pushed back by force again into the suction openings 5 ( 5 a to 5 b ), and the room area in the periphery is agitated, and the room temperature becomes uniform.
[0109] Next explanation is about setting condition of ventilation balance in a ventilation system in an applicable region of local ventilator PV including the discharge action by the discharger E, that is, the peripheral local region including the combustion heating type cooking device 1 , and also the entire kitchen in which the local ventilator PV is installed.
[0110] For example, supposing the local ventilator PV of the preferred embodiment is applied in the combustion heating type cooking device (a) shown in FIG. 19 , by installing the local ventilator PV, the ventilation balance should be established simultaneously in the entire kitchen and in the surrounding local area of the combustion heating type cooking device (a).
[0111] The main purpose of the local ventilator PV is to cover up for the majority of air lost by discharge by the downward blow intake stream 30 supplied like air curtain from the intake opening 35 around the discharge hood 15 , and the blow induction streams 21 , 21 , 21 , and therefore by minimizing the effects of the fresh air introduced as downward blow intake stream 30 on the indoor air conditioning, the air conditioning load is decreased, and a great energy saving effect is obtained.
[0112] By application of the local ventilator PV, by locally completing ventilation around the combustion heating type cooking device (a) shown in FIG. 19 , it is intended to minimize the introduction of fresh air by intake to be air conditioning load. For this purpose, discharge amount=intake (fresh air) amount+induction air stream+polluted air amount+indoor entrapped air amount, and the equation of discharge amount=intake (fresh air) amount is demanded ultimately.
[0113] More specifically, the suction flow rate of suction discharge stream 6 of the suction discharge stream generator 2 of the discharger E is set corresponding to the sum value of the blow flow rate of blow induction stream 21 by the blow induction stream generator 3 , the blow flow rate of the blow intake stream 30 by the intake device S, and the polluted air flow rate around the combustion heating type cooking device ( 1 ) guided by the blow induction stream 21 , and hence the balance of indoor air and local air is established simultaneously. In this case, the suction discharge stream 6 is discharged, and the blow induction stream 21 by the blow induction stream generator 3 and the guided air stream are covered by the indoor air, and the blow intake stream 30 is covered by the outdoor air.
[0114] In this relation, the blow flow rate of the blow induction stream generator 3 is set smaller than the suction flow rate of the suction discharge stream generator 2 .
[0115] In this case, the suction flow rate is determined by the suction side flow speed and guided air flow rate, and in this preferred embodiment, since the suction opening 5 is provided in the discharge box 11 , not directly in the discharge duct 10 , the suction side flow speed is the open side flow speed of the suction opening 5 .
[0116] The blow speed of the suction induction stream 21 is set same as the suction side flow speed of the suction discharge stream 6 . Hence, the suction discharge stream 6 and blow induction stream 21 are same in flow speed, and flow uniformly in same direction, differing only in the flow rate, and therefore an upward uniform stream passing near the periphery of the cooking device 1 (an always uniform stream, not changing from time to time, in the state of stream at a certain stream section) is formed locally.
[0117] Presently, there is a legal regulation about ventilation capacity, and when this local ventilator PV is applied in the ventilation system shown in FIG. 19 , if the calculated ventilation capacity is smaller than the specified standard, additional ventilation means may be added in the room to compensate for shortage in ventilation.
[0118] In the ventilation system in FIG. 19 , a discharge duct (k) having a ceiling discharge fan (j) may be used as additional ventilation means 50 .
[0119] This additional ventilation means 50 receives a detection or control signal from carbon dioxide sensor or the like (not shown) at other position than the local ventilation region by the local ventilator PV, and is driven automatically when running short of required ventilation capacity, and the indoor ventilation is increased to establish the ventilation balance.
[0120] In such configuration, the statutory standard values can be satisfied without increasing the capacity of the blower of the local ventilator PV.
[0121] Thus, in the discharger E of the preferred embodiment, as mentioned above, by the suction discharge stream 6 and blow induction stream 21 , an upward uniform stream high in controllability, passing around and near the combustion heating type cooking device 1 as cause of polluted air can be formed, and by the guiding action of the blow induction stream 21 , the polluted air around the combustion heating type cooking device 1 is collected and delivered by force into the suction discharge stream 6 . In other words, a stream of air from around the combustion heating type cooking device 1 toward the suction opening 5 of the suction discharge stream 6 is produced by force in the room, and this stream of air takes up the polluted air, and is brought to the suction opening 5 of the suction discharge stream 6 .
[0122] Thus, since the upward uniform stream for discharging the polluted air by force passes through the area of the combustion heating type cooking device 1 , and is discharged without enclosing the combustion heating type cooking device 1 , and there is no interference with the working area of the workers or cooks, and the habitability and working efficiency are not spoiled.
[0123] Besides, by completing the ventilation locally by discharge, the ventilation capacity and air conditioning capacity can be decreased, and the ventilation and air conditioning capacity can be kept low, and therefore the initial cost and running cost of invention and air conditioning facilities can be saved, and also consumption of electric energy is reduced, so that output of global warming gases can be reduced.
[0124] Further, since the ventilation capacity and air conditioning capacity can be decreased substantially, a sufficient allowance is made in the capacity of the existing power source and air conditioning facilities, and the existing ducts and other ventilation equipment can be directly utilized effectively.
[0125] The leading end 10 a of the discharge duct 10 of the suction discharge stream generator 2 is opened to the outdoor side, and its base end 10 b communicates with the discharge box 11 formed like a box container, and the suction openings 5 ( 5 a to 5 b ) of the suction discharge stream 6 are opened oppositely to the discharge box 11 in the room, and the disposing positions of the suction openings 5 ( 5 a to 5 b ) can be set freely within the discharge side range of the discharge box 11 , so that the existing ducts and others can be directly utilized effectively.
[0126] By the operation of the ventilation system having such discharge E and local ventilator PV, the local ventilation is completed in the discharge region of the discharger E and local ventilator PV as mentioned above, and the flow of air in this region is not a mixed state of various air streams same as in the conventional overall ventilation system in FIG. 19 , but is clearly separate between intake stream and discharge stream as shown in FIG. 1 , FIG. 3 , and FIG. 4 .
[0127] As a result, heat and fresh air having effects on circulation stream of air conditioner (i) are same as in general living quarters, and general ventilation capacity in the kitchen room, that is, ventilation by driving of the discharger (j) is also applicable to the indoor space other than ventilation region by driving of the discharger E, and hence the ventilation capacity is kept low to the level of general living quarters.
[0128] In other words, since local discharge and ventilation can be completely by the local ventilator PV, the ventilation capacity and air conditioning capacity in the entire kitchen can be reduced.
[0129] As a result, by suppressing the ventilation capacity and air conditioning capacity, the initial cost and running cost of invention and air conditioning facilities can be saved, and also consumption of electric energy is reduced, so that output of global warming gases can be reduced.
Embodiment 2
[0130] This preferred embodiment is shown in FIG. 7 , and it is a modification of blow induction stream generator 3 in embodiment 1.
[0131] That is, an induction stream generating device 122 of the induction stream generator 3 of the preferred embodiment is suspended from the discharge hood 15 by suspending means 54 such as SUS chain, and the upper part of the device main body 26 of cylindrical shape functioning also as straightening part is blow nozzle 28 having a blow opening 20 , and a blow fan 27 as induction stream source is vertically provided concentrically in the lower part of the device main body 26 , and its air source is indoor air.
[0132] The blow nozzle 28 is vertical and upright so that its axial line may pass nearly the center of the suction opening 5 of the discharge box 11 of the suction discharge stream generator 2 , and the blow induction stream 21 is blown out vertically upward toward the inside of the suction opening 5 from the blow opening 20 .
[0133] Other structure and action are same as in embodiment 1.
Embodiment 3
[0134] This preferred embodiment is shown in FIG. 8 , and it is a modification of blow induction stream generator 3 in embodiment 1.
[0135] That is, in the induction stream generator 3 of the preferred embodiment, the induction stream generating device 122 of embodiment 2 is an independent self-supporting type, disposed upright at the side of the cooking range stand 125 of the combustion heating type cooking device 1 by means of supporting leg 123 .
[0136] Other structure and action are same as in embodiment 1.
Embodiment 4
[0137] This preferred embodiment is shown in FIG. 9 , and it is a modification of blow induction stream generator 3 in embodiment 1.
[0138] That is, in the induction stream generator 3 of the preferred embodiment, an induction stream generating device 222 consists separately of device main body 26 and blow fan 27 of the induction stream generating device 122 in embodiment 2, and its air s source is outdoor air.
[0139] Specifically, the cylindrical device main body 26 is buried and disposed upright in the cooking range stand 125 of the combustion heating type cooking device 1 , and the lower part of the device main body 26 communicates with the outdoor side by way of intake duct 223 , and a stream straightening device 224 of cylindrical shape is installed in horizontal state to the outdoor end of the intake duct 223 , and the blow fan 27 as induction stream source is provided inside of this stream straightening device 224 horizontally and concentrically, and its air source is outdoor air.
[0140] Other structure and action are same as in embodiment 1.
Embodiment 5
[0141] This preferred embodiment is shown in FIG. 10 to FIG. 12 , and the local ventilator PV is for domestic kitchen in general household or relatively small building.
[0142] In this local ventilator PV, the suction discharge stream generator 2 is disposed at the upper position of the cooking device 1 installed near the room wall 60 , that is, closely to the indoor wall 60 in the area of ceiling 45 above the cooking device 1 , and the discharge duct 10 is opened to outdoor side by penetrating through the wall 60 , and discharge fan 12 is provided at the leading end 10 .
[0143] The discharge box 11 and discharge hood 15 of the suction discharge flow generator 2 are formed in a unit structure integral with the intake box 41 of the intake device S as shown in FIG. 11 .
[0144] The discharge hood 15 is formed to surround three sides of the suction opening 5 of the discharge box 11 , and the indoor wall 60 forms part of discharge hood 15 . By contrast, the intake opening 35 of the intake box 41 is disposed and formed to surround the outer periphery of the discharge hood 15 , excluding the portion of indoor wall 60 .
[0145] The intake duct 40 of the intake device S is opened to the outdoor side through an indoor wall 61 opposite to the indoor wall 60 from the intake box 41 , and intake fan 42 is provided at its base end 40 a.
[0146] The blow induction stream generator 3 is integrated with the combustion heating type cooking device 1 , and its specific structure is shown in FIG. 12 .
[0147] That is, the blow induction stream generator 3 has an induction stream generating device 22 integrally assembled in the cooking range stand 125 at the rear side of the cooking range stand 125 of the combustion heating type cooking device 1 .
[0148] In this induction stream generating device 22 , the upper part of the device main body 26 of hollow parallelepiped shape is blow nozzle 28 having blow opening 20 , and blow fans 27 , 27 as induction stream sources are provided horizontally and forward at the front side of the device main body 26 , and its air source is indoor air.
[0149] The blow nozzle 28 is composed so that its axial line may be extended toward the inside of the suction opening 5 of the discharge box 11 . That is, the blow nozzle 28 of the induction stream generating device 22 is obliquely upright, as shown in FIG. 10 , so that its axial line may pass nearly the center of the suction opening 5 , and the blow induction stream 21 is blown obliquely toward the inside of the suction opening 5 from the blow opening 20 .
[0150] In the discharger E having such configuration, by driving of discharge fan 12 of the suction discharge stream generator 2 , an upward suction discharge stream 6 consecutive into the suction opening 5 is formed, and by driving of blow fans 27 , 27 of the blow induction stream generator 3 , an inclined upward blow induction stream 21 is generated from the blow opening 20 of the blow nozzle 22 extending straightly into the suction opening 5 .
[0151] As a result, by both streams 6 , 21 , an upward uniform stream is formed to pass through a position around the combustion heating type cooking device 1 , and by the guiding action of the blow induction stream 21 by the blow induction stream generator 3 , the polluted air around the combustion heating type cooking device 1 including hot jet flow of contaminants generated by combustion and heating of the combustion heating type cooking device 1 is collected and delivered by force into the suction discharge stream 6 . The polluted air thus brought into the suction discharge stream 6 is discharged out of the room, together with the suction discharge stream 6 , by way of the discharge box 11 and discharge duct 10 .
[0152] In the intake device S, by driving of intake fan 42 , from the U-shaped intake opening 35 at the level of the ceiling 45 , a downward blow intake stream 30 is generated like air curtain, and by the air curtain action of the blow intake stream 30 , the polluted air escaping out of the discharge region of the suction opening 5 of the discharger E is pushed back by force again into the suction opening 5 , and the room air in this peripheral area is agitated, and the room temperature becomes uniform.
Embodiment 6
[0153] This preferred embodiment is shown in FIG. 13 , and it is a modification of blow induction stream generator 3 in embodiment 5.
[0154] That is, the induction stream generator 3 of the preferred embodiment is also integral with the combustion heating type cooking device 1 , and as shown in the drawing, an induction stream generating device 322 is integrally assembled at the rear side of the cooking range stand 125 of the combustion heating type cooking device 1 .
[0155] In this induction stream generating device 322 , the upper part of the device main body 26 of L-shaped rectangular parallelepiped shape of hollow shape is blow nozzle 28 having blow opening 20 at the back side of the table cooking range 1 e , and the horizontal portion 26 b of the device main body 26 composes a mounting section of cooking range stand 125 for mounting the table cooking range 1 e . In the front part of the horizontal portion 26 b , blow fans 27 , 27 as induction stream sources are provided horizontally and forward, and its air source is indoor air.
[0156] Other structure and action are same as in embodiment 1.
Embodiment 7
[0157] This preferred embodiment is shown in FIG. 14 , and it is a modification of blow induction stream generator 3 in embodiment 5.
[0158] That is, the induction stream generator 3 of the preferred embodiment is also integral with the combustion heating type cooking device 1 , and as shown in the drawing, an induction stream generating device 422 is integrally assembled into the combustion heating type cooking device 1 .
[0159] In this induction stream generating device 422 , the device main body 26 of hollow rectangular parallelepiped shape is disposed at the rear side of the cooking ranges of combustion heating type cooking device 1 , and the blow nozzle 28 has the blow opening 20 , and the horizontal portion 26 b of the device main body 26 composes the main body of the cooking ranges 1 f , 1 f , 1 f . In the front part of the horizontal portion 26 b , blow fans 27 , 27 as induction stream sources are provided horizontally and forward, and its air source is indoor air.
[0160] Other structure and action are same as in embodiment 1.
Embodiment 8
[0161] This preferred embodiment is shown in FIG. 15 , and it is a modification of blow induction stream generator 3 in embodiment 5.
[0162] That is, the induction stream generator 3 of the preferred embodiment is also integral with the combustion heating type cooking device 1 , and as shown in the drawing, an induction stream generating device 522 is integrally assembled into the back portion of the combustion heating type cooking device 1 .
[0163] In this induction stream generating device 522 , the device main body 26 of hollow truncated quadrangular pyramid shape is disposed at the rear side of the cooking ranges 1 f , 1 f , 1 f of combustion heating type cooking device 1 , and the blow nozzle 28 has the blow opening 20 , and blow fans 27 , 27 as induction stream sources are provided horizontally and forward in the front part of the device main body 26 , and its air source is indoor air.
[0164] Other structure and action are same as in embodiment 1.
Embodiment 9
[0165] This preferred embodiment is shown in FIG. 16 to FIG. 18 , in which the local ventilator PV is installed as smoke separator as principal component of a smoking room.
[0166] The smoking room R is shown in a plan view of FIG. 16 , in which two rectangular partition walls Ra, Rb are concrete walls, and other two walls Rc, Rd are class partition walls, and the partition wall Rc has an opening 70 for access of people. In the smoking room R, a smoking table 71 is disposed closely to the partition wall Rd, and the remaining indoor space is the smoking corner. On the smoking table 71 , plural (three in the shown embodiment) ash trays 72 , 72 , 72 are prepared so as to be removed and exchanged.
[0167] In the local ventilator PV of the preferred embodiment, the discharger E is provided in the smoking room R, and the intake device S is provided outside of the partition wall Rc of the smoking room R. The intake device S may be also provided inside of the partition wall Rc of the smoking room R.
[0168] The suction discharge stream generator 2 of the discharger E is disposed at a position above the smoking table 71 at the most concentrated position of cigarette smoke containing contaminants (nicotine, tar) as cause of polluted air, that is, in the portion of the ceiling 45 above the smoking table 71 , closely to the partition wall Rd.
[0169] The suction discharge stream generator 2 has a basic configuration same as in the foregoing preferred embodiments, and the leading end 10 a of the discharge duct 10 is opened to the outdoor side, and its base end 10 b communicates with the discharge box 11 , and the suction opening 5 is opened in the room, opposite to the bottom 11 a of the discharge box 11 . At the leading end 10 a of the discharge duct 10 , discharge fan 12 is provided as the discharge stream source.
[0170] The discharge box 11 in the illustrated preferred embodiment is formed like a box, and almost entire bottom 11 a of square shape is suction opening 5 . Inside the discharge box 11 , a dust collector 113 is provided for separating and removing oily matter in the discharge.
[0171] On the indoor side outer circumference of the suction opening 5 , discharge hood 15 of truncated quadrangular pyramid shape is provided. This discharge hood 15 is disposed as shown in FIG. 16 so as to overlap almost entirely with the top of the smoking table 71 except for the outer peripheral portion, and its inner peripheral wall (not shown) is formed in the truncated quadrangular pyramid shape inclined wall in a climbing slope toward the suction opening 5 .
[0172] The blow induction stream generator 3 is disposed upright near the inner periphery of the outer periphery disposing the center of the top of the smoking table 71 , that is, the ash trays 72 , 72 , 72 . The induction stream generating device 622 of the blow induction stream generator 3 is composed as shown in FIG. 17 and FIG. 18 , in which the top of the device main body 26 in long tubular shape is blow nozzle 28 having blow opening 20 , and blow fan (not shown) as induction stream source is provided in the lower part of the device main body 26 , and its air source is indoor air. The blow nozzle 28 is composed so that its axial line may be extended toward the inside of the suction opening 5 of the discharge box 11 .
[0173] In the discharger E having such configuration, by driving of the discharge fan 12 of the suction discharge stream generator 2 , an upward suction discharge stream 6 consecutive into the suction opening 5 is generated, and by driving of the blow fan of the blow induction stream generator 3 , an upward blow induction stream 21 is generated from the blow opening 20 of the blow nozzle 22 of the induction stream generating device 622 , extending straightly toward the suction opening 5 .
[0174] By these streams 6 , 21 , the upward uniform stream is formed to ascent and pass the center of the top of the smoking table 71 , and by guiding action of the blow induction stream 21 by the blow induction stream generator 3 , the polluted air including the cigarette smoke generated in the indoor space of the smoking room R mainly around the smoking table 71 is collected and delivered by force into the suction discharge stream 6 .
[0175] The intake device S, different from embodiments 1 to 8, is disposed independently of the discharger E, outside of the partition wall Rc of the smoking room R.
[0176] The intake device S has the base end 40 a of the intake duct 40 opened to the air in an adjacent room or to fresh air, and intake fan 42 as intake stream source is provided in the base end 40 a . The leading end 40 b of intake duct 40 communicates with the intake box 41 , and an intake opening 35 is opened in this intake box 41 , opposite to the outside of the opening 70 of the smoking room R. When air conditioned air in the adjacent room is used as the intake source of the intake device S, it is beneficial because the smoking room R is air conditioned somewhat, and independent air conditioner may not be required in the smoking room R, and the stream is the smoking room R is not disturbed.
[0177] The intake box 41 is a box container of rectangular parallelepiped, and the opening width of the intake opening 35 in this intake box 41 , that is, the air curtain blow width W 1 is set wider than the opening width W 2 of the opening 70 of the smoking room R.
[0178] The intake opening 35 is opened as shown in FIG. 16 , so as to be close to the partition wall Rc of the smoking room R in a plan view, and parallel to the partition wall Rc, and by the air curtain action of the blow intake stream 30 from the intake opening 35 , leak of polluted air out of the smoking room R can be effectively prevented.
[0179] That is, in the intake device S having such configuration, by driving of intake fan 42 , downward blow intake stream 30 is generated like air curtain from the intake opening 35 at the level of ceiling 45 , and this blow intake stream 30 flows into the smoking room R because the smoking room R is in negative pressure by the action of the discharger E. As a result, by the air curtain action of the blow intake stream 30 , the polluted air escaping out of the smoking room R, that is, outside of the discharge region of the suction opening 5 of the discharger E is pushed back again into the smoking room R, and further pushed back by force into the suction opening 5 .
[0180] Thus, in the smoking room R having such local ventilator PV, the majority of the discharge discharged by the discharger E is covered by the intake from the air curtain by the intake device S, and effects of discharge in air conditioning in the adjacent room are minimized.
[0181] In the technical standard of “Passive smoking prevention law” enforced in 2003, the air flow into the room is required to assure flow velocity of 0.2 m/sec at the opening position, and in the ventilation system using the local ventilator PV of the embodiment, a stream of air toward the suction opening 5 is produced by force in the smoking room R, and escape of contaminants (nicotine, tar) out of the room is prevented at a small air flow rate.
[0182] To conform to “Passive smoking prevention law”, if it is difficult to increase the ventilation capacity in the existing smoking room, or extension works of air conditioners are difficult physically or economically, the existing ducts and air conditioning facilities can be effectively utilized, and extra works are minimized.
Embodiment 10
[0183] This preferred embodiment is shown in FIG. 19 to FIG. 21 , in which the structure of the discharger E of the local ventilator PV in embodiment 1 is slightly modified.
[0184] In the discharger E of the preferred embodiment, guide plates 100 are provided individually in blow nozzles 28 , 28 , 28 of three induction stream generating devices 22 a , 22 b , 22 c , and the structure is designed to make use of Coanda effect.
[0185] That is, the guide plates 100 , 100 , 100 are provided as shown in FIG. 19 to FIG. 21 , to extend from the blow opening 20 of each blow nozzle 28 toward the inside of the suction openings 5 a , 5 b , and 5 c of the suction discharge stream generator 2 , and the blow induction stream 21 blown out from the blow opening 20 is guided securely and stably into the inside of the suction opening 5 a.
[0186] Specifically, the guide plate 100 of the first induction stream generating device 22 a is extended, as shown in FIG. 21 , from the blow opening 20 of the blow nozzle 28 in inclined upright position toward the first suction opening 5 a , and its upper edge 100 a is positioned slightly lower than the lower edge of the discharge hood 15 . The blow induction stream 21 from the blow opening 20 is attracted to one side of the guide plate 100 by Coanda effect, and is blown out obliquely upward along this one side, and finally guided into the inside of the suction opening 5 a.
[0187] On the other hand, the guide plates 100 , 100 of the second and third induction stream generating devices 22 b , 22 c are extended, as shown in FIG. 20 , from the middle of blow openings 20 , 20 of the blow nozzles 28 , 28 in vertical upright position toward nearly the middle of the second and third suction openings 5 b , 5 c , and their upper edge 100 a is positioned slightly lower than the lower edge of the discharge hood 15 . The blow induction stream 21 from the blow opening 20 is attracted to both sides of the guide plate 100 by Coanda effect, and is blown out obliquely upward along the both sides, and finally guided into the inside of the suction openings 5 b , 5 c.
[0188] In the discharger E having such configuration, by driving of discharge fans 12 , 12 of the suction discharge stream generator 2 , upward suction discharge streams 6 , 6 , 6 consecutive to the inside of suction openings 5 ( 5 a to 5 c ) are generated, and by driving of blow fans 27 , 27 , . . . of the blow induction stream generator 3 , upward blow induction streams 21 , 21 , 21 are generated, extending from the blow opening 20 of the blow nozzle 22 in the induction stream generating devices 22 a , 22 b , 22 c , straightly toward the suction openings 5 ( 5 a to 5 c ).
[0189] In this case, the blow induction stream 21 from each blow opening 20 is attracted to the guide plate 100 by Coanda effect of the guide plate 100 , and is stably accelerated (at double speed, approximately, without guide plate 100 ), and is securely guided into the inside of the first, second, and third suction openings 5 a , 5 b , 5 c . In other words, in the discharge E of the preferred embodiment, the blow induction stream 21 is same in air flow rate as in embodiment 1, while the speed is increased and the stream is stabilized.
[0190] The upward extending length of guide plate 100 may be properly determined depending on the purpose of place of installation as far as Coanda effect may be expressed effectively. For example, in the illustrated preferred embodiment, the upper edge 100 a of guide plate 100 is extended slightly lower than the lower edge of the discharge hood 15 , but it may be further extended up to the inside suction openings 5 ( 5 a to 5 c ).
[0191] If the blow openings 20 and first, second and third suction openings 5 a , 5 b , 5 c are not provided on a straight line, but are biased, when the guide plate 100 is deflected, and guide surfaces from the blow openings 20 , 20 , 20 to the first, second and third suction openings 5 a , 5 b , 5 c are formed, by Coanda effect, the axis of blow induction stream 21 linking these upper and lower openings 20 , 5 ( 5 a , 5 b , 5 c ) by curves can be formed.
[0192] Other structure and action are same as in embodiment 1.
[0193] The foregoing embodiments 1 to 10 merely show preferred examples of the invention, and the invention is not limited by them alone, but may be changed and modified freely within the scope thereof.
INDUSTRIAL APPLICABILITY
[0194] As specifically described herein, according to the invention, by suction discharge stream and blow induction stream, an upward uniform stream high in controllability passing around the contaminant source to cause polluted air is formed, and by the guiding action of blow induction stream, the polluted air around the contaminant source is collected and delivered by force into the suction discharge stream, and therefore the upward uniform stream for discharging the polluted air by force can be discharged without enveloping the contaminant source by passing around the contaminant source, and there is no interference with the working area of the workers, and the discharge and ventilation technology not spoiling habitability and working efficiency can be presented.
[0195] By completing ventilation locally by discharge, the ventilation capacity and air conditioning capacity can be decreased, and the capacity of ventilation and air conditioning facilities can be kept low, and the initial cost and running cost of ventilation and air conditioning facilities are saved, and also by reduction of consumption of electric energy, output of global warming gases can be decreased.
[0196] As a result of considerable decrease of ventilation capacity and air conditioning capacity, a sufficient allowance is made in the exiting power source capacity and air conditioning capacity, and existing ducts and other ventilation facilities can be directly utilized effectively.
[0197] The leading end of the discharge duct of the suction discharge stream generating means is opened to the outdoor side, and its base end communicates with the discharge box formed as box container, and the suction opening of the suction discharge flow is opened in the room opposite to this discharge box, and hence the position of the suction opening can be set freely within the discharge side range of the discharge box, and the degree of freedom of layout of the source of contaminant, such as cooking device, can be increased, and existing ducts and others can be effectively utilized.
[0198] In other words, in recent modifications of existing buildings, heat generating appliances are intensively installed such as office automation equipment and electrical appliances, and capacity shortage of power source and air conditioning is a serious problem. Such modification works are therefore often accompanied by extra works for electrical or air conditioning facilities, and the cost is increased. According to the invention, as discussed above, the air conditioning and ventilation capacity can be decreased from the conventional level, and an allowance is made in the existing power source capacity and air conditioning capacity, and the existing ducts (air passages) can be used, and there is still an allowance, and extra works are decreased.
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To present technology of discharge and local ventilation capable of decreasing ventilation capacity and air conditioning capacity substantially by lowering the air conditioning load by introduction of fresh air by intake, and decreasing the capacity of air conditioning and ventilation facilities by eliminating consumption of electrical energy.
This a method of discharging polluted air near combustion heating type cooking device ( 1 ) in a room having combustion heating type cooking device ( 1 ) to cause polluted air, comprising the steps of generating upward suction discharge stream ( 6 ) from upward position of the combustion heating type cooking device ( 1 ) to outdoor air, generating upward blow induction stream ( 21 ) from the position near the side of the combustion heating type cooking device ( 1 ) to the suction discharge stream ( 6 ), and by inductive action of this blow induction stream ( 21 ), taking up the polluted area near the surrounding of the combustion heating type cooking device ( 1 ) and forcibly collecting and delivering into the suction discharge stream ( 6 ).
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CROSS REFERENCE TO RELATED APPLICATIONS
The present application claims priority from Provisional Patent Application 60/479,140 filed Jun. 17, 2003, the disclosure of which is incorporated by reference herein.
BACKGROUND OF THE INVENTION
The present invention relates to a device and system providing for scuba tank transport over land and particularly to a system in which the device may remain connected to the scuba tank during diving.
Self-contained underwater breathing apparatus (SCUBA) comprises a cylindrical gas bottle. The cylinder generally has a circular cross section centered about a central axis. Scuba tanks having other cross sections have been provided in the prior art as well. Commonly, the gas bottle is made of steel. Aluminum gas bottles have also been provided. Generally, one end of the cylinder is substantially flat and an opposite end of the cylinder has a dome shape. The center of the dome has an internally threaded aperture that receives a valve assembly. The valve assembly includes an elongated nipple end that is coaxial with the cylinder's central axis and a valve extending through the nipple end mounted substantially normal to the central axis. The valve may include a regulator. Alternatively, the regulator may external to the scuba tank and be coupled to the valve. Air hoses and a mask are coupled to the valve assembly for use in underwater breathing. Scuba tanks are manufactured in a variety of standardized sizes.
A nominal weight for a scuba tank fully charged with air (or other oxygen-containing mixture) is 30 lbs. When the scuba tank is deployed underwater, the weight of the scuba tank is not of concern to a diver. Due to displacement of water, the weight felt by the diver is reduced. Also, divers need to wear weights to offset their own buoyancy. Consequently, the weight of the scuba tank does not adversely affect mobility of a diver in the water. However, on land, the full weight of the scuba tank must be supported. A user may wish to have a convenient way of transporting the scuba tank from one place to another, for example as from a parking lot to a boat marine on a dock, rather than having to carry the scuba tank. A user may need to transport a scuba tank across a parking lot, on a beach or along a dock, for example. Many prior art carriages have been provided for transporting a scuba tank. These carriages include dollies and hand trucks. These carriages are not normally assembled to the scuba tank when then tank is being transported to a diving area, e.g., in the trunk of a car. They must be removed from the scuba tank prior to diving.
Prior art carriages are generally stored in transport containers, e.g., car trunks, separately from the scuba tanks. If a the scuba tank is placed in the transport container by itself, the scuba tank is subject to rolling due to its circular cross section. Rolling of the scuba tank can cause damage to it or the container. One way to avoid rolling is by providing a separate device to prevent rolling or a separate box or other enclosure in to which to fit the scuba tank. Use of additional devices presents added inconvenience and expense in preventing the scuba tank from rolling.
When a diver reaches a destination, the scuba tank must be assembled to the carriage prior to transporting the scuba tank to a point at or near which the diver will enter the water. Then the scuba tank must be dissembled from the carriage.
The diver must then carry the tank from the place of disassembly from the carriage to the location at which the scuba tank will actually be donned. Divers will generally enter the water from a dock, a beach or a boat. They may find it very inconvenient to have to carry the scuba tank from a place of secure storage for a carriage to a water entry point. If they use the carriage to get to the water entry point, the must leave the carriage unattended while diving. Carriages left on a dock may provide an inconvenience or safety hazard to other users of the dock. There may be not article on the dock to which the carriage can be secured. In this case, the carriage could be used or removed by others while the diver is away from the dock. If entering the water from a beach, a diver would have to be able to return to the same spot on the beach from the water to find the carriage and avoid carrying the scuba tank over the beach. On some boats, lack of stowage space may result in great inconvenience in stowing the carriage. On a diving party boat, a number of carriages would have to be stowed, and divers would encounter the usual inconveniences associated with baggage retrieval to find their own carriages.
Carriages are not suited for remaining attached to the scuba tank during diving. Their dimensions create the potential for snagging should a swimmer pass through vegetation. Their shapes could project into a volume to be occupied by the body of a diver were they to be strapped to a diver's body.
SUMMARY OF THE INVENTION
It is a general advantage of embodiments of the present invention to provide a device and system of which is simple in construction and permits on-shore transport of a scuba tank.
It is a particular advantage of embodiments of the present invention to provide a device and system of the type described which acts as an aid in stabilizing a scuba tank during transport of the scuba tank in a container.
It is another particular advantage of embodiments of the present invention to provide a device and system providing on-shore mobility for a scuba tank and which may also be conveniently left affixed to a scuba tank during diving.
Briefly stated, in accordance with embodiments of the present invention, there are provided a scuba tank mobility device and a system comprising a scuba tank in a mobility device. The transport device is mountable to a first end of a scuba tank remote from a second, valve end of the scuba tank. The first end is often referred to for purposes of the present description as the lower end since it will be on the bottom when the scuba tank is vertically disposed. The transport device fits over the first end of the scuba tank and includes a cup member. The cup member may be fitted directly over the scuba tank or over a scuba tank boot. A tank boot is a flat-bottomed, usually plastic, vinyl or rubber device that fits over the lower end of a scuba tank, allowing the tank to stand up. The boot also protects the bottom of the scuba tank from abrasion and provides some degree of cushioning of the impact of a tank when it strikes a surface. A roller member is mounted to rotate with respect to the cup member and positioned vertically with respect to bottom of the cup member so that the roller permits standing support of the scuba tank. Tilting may be achieved by applying a force to the nipple end of the scuba tank. The tank is tilted from the standing position to place weight on the roller member. Tilting may be achieved by applying a force to the nipple end of the scuba tank. In one form, retaining strap axially surrounds the scuba tank and is axially displaced from the cup member. A connecting member connects the cup member to the retaining strap. The cup member comprises a projection to limit rolling of the scuba tank when its axis is substantially horizontal. In a further form, a handle may be attached to the cup member and extend axially therefrom. The handle may be opened to extend past the valve end of the scuba tank and fold to have a radial extent less than that of the scuba tank. The cup member and handle are dimensioned to provide minimal projection from the contour of the scuba tank, whereby potential for a tangling with underwater vegetation and other objects is minimized.
While this Summary of the Invention section lists various aspects of varying embodiments of the present invention, there are other aspects of the present invention, or preferred embodiments thereof, apparent from the following description. This Summary is neither exhaustive nor intended to be determinative of the scope of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the invention are pointed out in the following description taken in connection with the following drawings.
Of the drawings:
FIG. 1 is a side elevation of a device and system constructed in accordance with the present invention;
FIGS. 2 and 3 are a side elevation and a rear elevation of the embodiment of FIG. 1 ;
FIG. 4 is a plan view of a cap member to receive a lower end of a scuba tank;
FIG. 5 is an elevation of a further embodiment of the present invention illustrating a handle in a first state;
FIG. 6 is a side elevation of the apparatus of FIG. 4 illustrating the handle in a second state;
FIGS. 7 and 8 are a rear elevation and a side elevation of a further embodiment of the present invention in which a handle is provided for use in transport; and
FIGS. 9-17 illustrate a further embodiment of the present invention in which FIG. 9 is a front axonometric view;
FIG. 10 is a side elevation;
FIG. 11 is a front elevation;
FIG. 12 is a rear elevation;
FIG. 13 is a rear axonometric view;
FIG. 14 is a front axonometric view;
FIG. 15 is a plan view;
FIG. 16 is a bottom plan view;
FIG. 17 is a cross-sectional view taken along lines 17 - 17 of FIG. 15 ; and
FIGS. 18 and 19 are an elevation and a plan of a further form of the embodiment of FIGS. 9-17 .
DETAILED DESCRIPTION
In the embodiment of FIG. 1 , a scuba tank 1 has an axis 2 . Scuba tanks generally comprise cylindrical gas bottles symmetrical about the axis 2 . The scuba tank 1 has an upper end 6 and a lower end 7 . The upper end 6 comprises top part 8 a control valve 9 . Commonly, the lower end 7 is flat. The scuba tank 1 has a horizontal centerline 12 which is approximately a registration with a weight-balanced point of the tank 9 when it is weighed with the axis 2 in a substantially horizontal disposition.
FIG. 2 is an elevation of the scuba tank 1 engaged in a mobility device comprising a transport carrier 20 constructed in accordance with an embodiment of the present invention.
FIG. 3 is a rear elevation of the scuba tank 1 partially broken away and engaged in the transport carrier 20 . FIG. 4 is a plan view of the transport carrier 20 with the scuba tank 1 removed therefrom.
The transport carrier 20 comprises a platform section 22 supporting a cup member 25 which receives the lower end 7 of the scuba tank 1 . A brace member 28 extends in an axial direction from the platform member 22 across the cup member 25 to an axial upper position 27 , preferably below the vertical centerline 12 . A strap member 29 is secured to the brace member 28 for maintaining the scuba tank 1 is engagement with the transport carrier 20 . As seen in FIG. 3 , the strap member 29 may be threaded through slots 31 and 32 at an upper portion of the brace member 28 . A buckle 34 may be used to secure and loosen the strap 29 .
For transport, a roller member 40 is provided supported to the platform 22 . As seen in FIGS. 3 and 4 , the roller member 40 may comprise first and second wheels 42 and 43 , each placed on a different horizontal side of the brace 28 . The roller member 40 is sized and positioned to permit the platform 22 to support the scuba tank 1 in a standing position. Additionally, the roller member 40 is vertically positioned to minimize tilting of the axis necessary to transfer weight from a bottom of the platform 22 to the roller member 40 . In a preferred form, the outer diameter of the roller member 40 is tangent to the lower surface 23 of the platform 22 . The wheels 43 and 42 may, for example, comprise urethane wheels. It is desirable to make them large enough to conveniently support the weight of the scuba tank 1 and small enough to minimize their contribution to the size of the transport carrier 20 . In one suitable embodiment, the wheels 42 and 43 are 1½″ wide and 4″ in diameter. The roller member 40 rotates on an axis 46 . Individual axial pins 48 and 49 may secure the wheels 42 and 43 respectively along the axis 46 , as illustrated in FIG. 3 . Alternatively, as illustrated in FIG. 4 , a single axle 52 may be provided.
It is highly desirable to give the transport carrier 20 a contour such that the shape will minimize engagement with underwater vegetation or any other objects. To this end, projections from the transport carrier 20 are minimized. As seen in FIG. 4 , the transport carrier 20 has an annular section 54 surrounding the “footprint” of the scuba tank 1 having an inner diameter d 1 and an outer diameter d 2 with a common center point 56 . In order to avoid the use of projections, solid areas 62 and 63 extend from the annular portion 54 to the wheels 31 and 32 . In one suitable embodiment, the areas 61 and 62 each comprise quadrants of a square having a center point 56 and a side d 2 with the central area 53 removed therefrom. A side 64 of the square is substantially normal to the sides 63 and 64 . Arrow shaped cutouts 69 and 70 may be provided adjacent the wheels 31 and 32 respectively. The cutouts 69 and 70 are cut out from corners of the quadrants 61 and 62 . Additionally, bosses 75 and 76 may be provided diametrically interiorly of the wheels 31 and 32 respectively and extending radially away from the side 64 to cover portions of the wheels 31 and 32 . In accordance with the present invention, the dimensions of the transport carrier 20 and wheels 31 and 32 are selected to provide sufficient size to support conveniently the weight of the scope of tank 1 out of the water for minimizing projections from the scuba tank so that the potential for tangling of the transport carrier 20 in the water is minimized.
It is noted that in the preferred form, the strap 29 is below the vertical centerline 12 because in customary scuba usage, other apparatus must be affixed thereabove. For example, a shoulder harness worn by the diver (not shown) is affixed above the centerline 12 . This design further accommodates convenience of use.
FIGS. 5 and 6 are rear and side elevations of a further embodiment of the present invention. The transport carrier 20 is mechanically coupled to a handle 80 so that a diver may grasp the handle 80 for transporting the scuba tank 1 rather than having to grasp the scuba tank by the top 6 or the valve 8 . The handle 80 is substantially horizontally disposed to first and second arms 83 and 84 which telescope respectively within support arms 85 and 86 . The support arms 85 and 86 are anchored in the platform 20 . Securing means 87 at the top of arm 85 and securing means 88 at the top of arm 86 may be selectively moved between an open position which allows vertical sliding of the handle 80 in a closed position in which the position of the handle 80 is fixed. There are many well-known forms of such couplers. In one common form, they comprise threaded annular nuts which tighten bifurcated ends of the arms 85 and 86 . For overland transport, the handle 80 is moved to its vertically top position for diving or for transport in a container such as car trunk, the handle 80 is moved to its lowest position and the arms 83 and 84 are received inside the arms 85 and 86 .
FIGS. 7 and 8 represent a further embodiment in which a handle 180 is affixed to arms 183 and 184 having upper ends joined by the handle 180 and lower ends anchored in the platform 22 . Handles 183 and 184 include pivots 185 and 186 respectively. Additionally, locks 187 and 188 are provided for locking the handle assembly 178 in a closed position or an open position, the closed position being illustrated in FIG. 8 .
The pivots 185 and 186 need not necessarily be placed below the vertical centerline 12 . However, the pivots 185 and 186 should be below the point at which it is expected to attach the harness 17 .
FIGS. 9-12 each represent a system 210 comprising a scuba tank 201 having a top 206 and a transport carrier 220 including a cup member 225 . An intermediate member 230 may comprise a boot which a user has placed on the scuba tank 201 . Alternatively, the intermediate member 230 may comprise a shim to be placed intermediate the transport carrier 220 and the scuba tank 201 for a user not having a boot on the scuba tank 201 .
Additionally, as better seen in FIGS. 10 and 12 , protector members 240 may be affixed to the scuba tank 201 to protect the scuba tank 201 when it is being rolled upstairs. The protector members 236 may be affixed to the scuba tank 201 by two-sided tape pieces 237 . In the present embodiment, a roller member 240 comprises first and second wheels 242 and 243 . The wheels are mounted to axle members 244 and 245 , respectively as further explained with respect to FIG. 17 below. To provide for a convenient means of inserting and removing the scuba tank 201 from the cup member 225 , a vertical recess 250 is cut in the circular periphery of the cup member 225 . The vertical recess 250 is best seen in FIGS. 12 and 13 . FIGS. 13-17 are respectively a rear axonometric, front axonometric, plan view, bottom plan view and a section view taken along lines 17 - 17 of FIG. 15 of the present embodiment with the scuba tank 201 removed there from. The vertical recess 250 is preferably a V-shaped slot. The “V” is selectably closeable to vary the inner diameter of the cup member 225 . An outer periphery 258 of the cup member 225 has a vertically extending channel 260 for receiving an adjustable strap assembly 265 . The adjustable strap assembly 265 includes a strap 266 and a clasp assembly 268 . In a first position, the clasp assembly 268 is open and the strap 266 has a first outer diameter permitting the vertical recess 250 to be open to its full extent and provide a clearance for the scuba tank 201 . In a second position, the clasp assembly 268 is closed. The outer diameter of the strap 266 is reduced, compressing the cup member 225 and reducing the outer diameter of the channel 265 . Consequently, the cup member 225 is moved to a closed position as illustrated in FIG. 14 . This provides a tight fit retaining the scuba tank 201 in the cup member 225 .
Referring now to FIG. 10 , it will be seen that in a preferred form, the roller member 240 cooperates in providing a standing position for the transport system 210 . The bottom of the roller member 240 at a horizontally rear portion of the cup member 225 and the lower extent of the cup member 225 at a horizontally front portion thereof define a horizontal plane 280 on which the system 210 may rest in an upright position. The horizontally rear portion of the cup member 225 has an elevated bottom 290 which serves as a platform for supporting the scuba tank 201 . Vertically projecting below the platform 290 at a forward horizontal extent of the cup member 225 is a lip section 292 . A user may use the lip section 292 as a grip. Consequently, the system 210 may be carried by a user placing one hand at the upper end 206 of the scuba tank 201 and another hand at the lip 292 of the cup member 225 .
The roller member 240 is further described with reference to FIGS. 15 and 17 . The axle members 244 and 245 may each comprise an L-shaped member 300 with a horizontal arm 301 projecting from the cup member 225 and a vertical arm 302 projecting from an upper surface of the cup member 225 . The horizontal arms 301 are disposed along and axis 304 which intersects an interior of the cup member 225 . This disposition of the axis 304 allows for a reduced radial distance of the axle 304 from a center of the cup member 225 . Consequently, a wheel 242 and a wheel 243 do not project as far from the cup member 225 as they would if the axle 304 were outside the circular contour of the cup member 225 . A smaller profile is thus provided to underwater vegetation and other objects.
The wheels 242 and 243 are each secured to one arm 301 by a securing means 306 such as a washer press fit onto the arm 301 . Other well-known securing means may be used. The vertical arm 302 may be threaded at an upper-end thereof and receive a lock nut 310 . The lock nut 310 may be an individual lock nut as illustrated in FIG. 17 . Alternatively, the lock nut 310 can be secured to a handle assembly such as that illustrated in FIG. 5 in order to prevent securing a handle assembly to the cup member 225 . The wheels 242 and 243 in one form are made of polycarbonate resin.
As seen in the embodiment of FIG. 17 , the wheels may have an oval cross section with a recess 315 formed at an outer periphery thereof. The wheels 242 and 243 have one thickness at the center, or inner diameter, and a smaller thickness at their outer diameters. The recess 315 may receive an o-ring 318 . A suitable material for the o-ring 318 is hard rubber. The o-ring 318 provides traction. The o-ring 318 is also easily replaceable so that where at the outer periphery of the roller member 240 does not require replacement of an entire wheel 242 or 243 . The recess 315 is formed to accommodate different size o-rings which may serve different purposes. For example, a smaller diameter o-ring 318 may be more suitable for use over docks and parking lots. A larger o-ring 318 may be more suitable for use on a beach.
The L-shaped members 300 are received in projections 322 and 323 extending from the circular contour of the cup member 225 . As best seen in FIG. 17 , each vertical arm 302 extends through a bore 325 . The horizontal arms 301 are each received in a slot 327 . The slots 327 have a top end 328 against which the arms 301 stop when the vertical arms 302 are secured by the lock nuts 319 . The positions of the slot top ends 328 are dimensioned to place the horizontal arms 301 on the axis 304 .
As seen in FIG. 14 , the platform portion 290 of the cup member 225 need not extend across the total horizontal extent of the inner diameter of the cup member 225 . The platform member 19 includes a central aperture 330 defining an annular member 332 between the aperture 330 and vertical wall of the cup member 225 . Additionally, circumferentially spaced apertures 334 are placed in the annual section 332 , further reducing weight of the cup member 225 .
As will be seen in FIGS. 15 and 16 , the structure of the transport assembly 220 will prevent rotation when the assembly 210 is restored in a horizontal position in a storage means. The cup member 225 and roller member 240 comprise means for preventing rotation. In other words, either a roller member 240 may provide a stop to prevent rotation or a corner member 340 projecting from a circular portion of the cup member 225 or both may prevent rotation. The description of stop means being comprised in the roller member and cup member 225 is used to denote that either or both of the members may be utilized to prevent rotation.
FIGS. 18 and 19 are an elevation and a plan view of a further embodiment in which wheels 242 and 243 are mounted to a one-piece axle 350 . Projections 322 and 323 are dimensioned to provide bores 352 to locate the axle 350 outside the circular contour of the cup member 225 .
Many departures may be made to provide a transport apparatus constructed in accordance with the present invention as well as a system comprising a transport apparatus and scuba tank. If desired, further aerodynamic shaping could be provided. For example, the upper surface of the annular section 54 could be rounded rather than flat. The entire transport mechanism 20 could be surrounded in a spherical, teardrop or other rounded shape. Fins could be provided. The restraining strap 28 could be a unitary elastomeric member. Many further modifications may be made in accordance with the above teachings to provide an apparatus and system which provides for convenient transportation and for unobtrusive use underwater.
Embodiments of the invention can be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications are intended to be within the scope of the invention.
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A scuba tank mobility device and a system comprise a cup member that may be fitted directly over the scuba tank or over a scuba tank boot. A roller member is mounted to rotate with respect to the cup member and positioned vertically with respect to bottom of the cup member so that the roller permits standing support of the scuba tank. The tank is tilted from the standing position to place weight on the roller member for transport. The cup member comprises a projection radially outside its diameter to limit rolling of the scuba tank when on its side. In a further form, a handle may be attached to the cup member and extend axially therefrom. The cup member and handle are dimensioned to provide minimal projection from the contour of the scuba tank, whereby potential for a tangling with underwater vegetation and other objects is minimized.
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This application is a continuation of Ser. No. 422,491 filed on Sept. 23, 1982, now abandoned, which is a divisional of Ser. No. 212,173 filed on Dec. 2, 1980, now U.S. Pat. No. 4,364,803.
DESCRIPTION
1. Technical Field
The present invention concerns new and improved electrodes, electrode-membrane systems, the process for preparing the same and the use thereof in aqueous solution electrolysis, particularly in the electrolysis of halide solutions.
2. Background Art
Solid electrolyte cells have long been known and utilized as fuel cells. More recently solid electrolyte cells have been developed which are suitable for water electrolysis to produce hydrogen and oxygen and for alkali metal halide electrolysis to produce halide, hydrogen and alkali metal hydroxide.
The electrodes are often comprised of a thin and porous layer of particles of a conducting and non-passivatable material, typically a metal belonging to the platinum group, or a conducting oxide of said metal, directly embedded in or otherwise bonded to the membrane surface by means of a binder, typically a polymer of trifluoroethylene and/or tetrafluoroethylene.
The electrodes are formed and bonded to the membrane surface by hot-pressing the catalyst particles and the binder.
In the particular case of sodium chloride electrolysis, the anode is often constituted by ruthenium and titanium mixed oxide particles, preferably also containing iridium, while the cathode, bonded to the opposite surface of the membrane, is often constituted by platinum black particles mixed with graphite particles.
The hot molding process for forming electrodes directly onto the membrane surface involves, however, several problems and high costs. Furthermore, during cell operation, the catalyst particles are often removed and this of course shortens the life of the electrodes due to the fact that the electrocatalytic material loss increases the cell voltage.
Chemical deposition of these porous films of electrocatalytic material, as an alternative process for preparing the electrodes, is a known procedure (see U.S. Pat. No. 3,423,228); however, this technique is rarely chosen in lieu of the above-mentioned hot molding technique, due to the fact that, though it provides highly catalytic electrodes, it involves a too high consumption of noble metals in order to obtain adequate and uniform coating of the whole membrane surface. Also, the deposit thus obtained tends to come off especially when gas evolves at the electrode, as in the case of electrolysis of aqueous solutions.
SUMMARY OF THE INVENTION
According to the present invention, a new and improved process for forming said electrodes directly onto the surface of semipermeable membranes is provided.
According to this invention, it has surprisingly been found that by modifying the charge distribution at least on the surface of the membrane before carrying out the chemical deposition of the metal thereon, the structure of the metal coating obtained is improved, and above all the adhesion of the metal layer to the membrane surface is improved.
According to the process of the present invention, metal films are provided which are sufficiently porous to permit ready permeation by the electrolyte and by the gas bubbles evolved at the electrode-membrane electrolyte interface, while being substantially continuous and uniform and presenting high electrical conductivity. Furthermore, uniform coating of a certain electrodic surface is obtained with a minimum quantity of noble metal. Moreover, the electrodes thus formed exhibit an outstanding stability and durability, even under gas evolution conditions as encountered in the electrolysis of aqueous solutions and especially for chlorine production.
In accordance with another aspect of the present invention, uniform and continuous films of palladium can be provided even without pretreatment of the membrane with an amphoteric material.
According to another aspect of the present invention, structures are provided with metallic palladium deposited on the surface of the ion-exchange membrane and at least a second layer deposited on the palladium of at least one material from the group of platinum, nickel, nickel sulphide, nickel polysulphate, palladium sulphide, palladium polysulphide, cobalt, cobalt polysulphide or cobalt sulphide.
A further aspect of the present invention includes the changing of the grain size of a metal layer from coarser to finer, by contacting with an amalgam in the presence of water.
The present invention is also concerned with a structure comprising a polymeric ion-exchange membrane containing amphoteric groups on the surface thereof.
The present invention is also concerned with a process for providing amphoteric groups on a polymeric membrane which comprises contacting a polymeric ion-exchange membrane with a solution of an amphoteric compound capable of being sorbed by the polymeric membrane.
DESCRIPTION OF PREFERRED AND VARIOUS EMBODIMENTS
The membrane subjected to treatment is usually comprised of a thin sheet of ion-exchange resin and is substantially impervious to gas and liquid flow. Advantageously, it is constituted by a polymer of a fluorocarbon such as tetrafluoroethylene or trifluoroethylene containing ion-exchange groups, and in particular cation-exchanging groups, such as --COOH, --SO 3 H, COONa, --SO 3 Na, and --SO 2 NH 2 ; although, it may contain anion-exchanging groups with or without cation-exchanging groups.
Homopolymers of fluorocarbons, copolymers of fluorocarbons with each other or with other ethylenically unsaturated monomers, and/or mixtures of such polymers can be employed if desired.
The preferred amounts of ion exchange groups in the polymeric membrane can be expressed in terms of equivalent weight of the polymer. Typical polymers particularly suitable in the electrolysis of halides have equivalent weight of about 900 to about 1500. Alternatively, the polymer can be further defined by its ion exchange capacity, preferred values of which being about 0,5 to about 4,0 milliequivalent per gram of dry polymer.
Suitable membranes for the process of the invention are widely described in various U.S. Pat. Nos.: 4,065,366, 4,124,477, 3,948,373; 3,976,549; 3,282,875, 3,773,643; 4,081,349 and 4,025,405, whose descriptions are incorporated herein by reference.
Commercial membranes particularly useful for the process of the invention include membranes produced by E. I. DuPont under the trade designation of "Nafion", by Asahi Glass (Japan) under the trade designation of "Flemion", and by Asahi Chemical (Japan) under the trade designation of "Aciplex".
The membrane thickness is generally in the range of about 0.1 to 1 millimeter.
A preferred process of the present invention includes soaking the membrane in water to full swelling, roughing the surface by wet sandblasting or other equivalent technique, and then contacting the membrane with an organic material capable of reacting both as an acid and as a base. Generally the materials contain an amine radical as well as a carboxylic or carboxyamide radicals or are water soluble metal salts thereof such as alkali metals salts thereof. Preferably, the materials used are water soluble and an aqueous solution thereof is used to effect the desired contact. For example, such an aqueous solution contains at least one of the following compounds:
sulphamic acid and its dissociation derivatives:
NH.sub.2 SO.sub.3 H=NH.sub.2 SO.sub.3.sup.- +H.sup.+ or H.sub.3 N.sup.+ -SO.sub.3.sup.-
alanine and its dissociation derivatives: ##STR1## thioalanine and its dissociation derivatives: ##STR2## thiourea and their derivatives: ##STR3## other compounds which may be used include ammonium carbamate, urea hydrochloride and cyanuric acid.
These compounds exhibit common characteristics which can be summarized as follows:
(i) amphoteric behaviour (i.e. they act both as acid or base);
(ii) their acid character generally is stronger than their basic one;
(iii) close packing of the molecular complex (i.e. relatively small molecule);
(iv) high solubility in water.
Due to the same characteristics, they are readily adsorbed by the ion-exchange resin constituting the membrane, in the vicinity of the active sites of the resin, that is to say, in the vicinity of the ion-exchange groups contained in the membrane. In particular, in the presence of cationic membranes, the acid groups contained in the resin interact with the basic parts of the amphoteric polar groups of the above mentioned compounds to form a pseudo-dative bond. While the electro-negativity of the acid groups of the membrane is not completely eliminated, the acid parts of the adsorbed compounds produce new electro-negative sites labily attached to the polymeric membrane structure.
The concepts may be graphically visualized in the following scheme, wherein the adsorption of NH 2 SO 3 H by a polymeric membrane of the type R--SO 3 H is illustrated.
(i) NH 2 SO 3 H dissociation reaction: ##STR4##
(ii) Mutual adsorption model: ##STR5##
Therefore, the membrane electronegativity profile results in more unformity and is more continuous since the basic moiety +NH 3 tends to slightly diminish the electronegativity of the SO 3 - groups contained in the polymer, while the new adsorbed SO 3 - groups give rise to as many new electronegativity sites, which are spatially intermediate among the existing SO 3 - groups bound to the polymer.
The membrane is then contacted with a solution of the selected metal salt, which is adsorbed and/or adsorbed in the vicinity of the membrane active sites, represented by the polar groups of the polymer itself and the polar groups preadsorbed.
Sorption of the metal salts takes place mainly on the membrane surface and is a function of the contact time and temperature for a certain depth from the surface exposed to contact with the solution.
When the adsorption or absorption of the metal salts or at least wetting by the solution thereof is accomplished, the membrane is soaked in a solution containing a reducing agent adherent to the membrane surface. These two last operations are repeated for a certain number of times sufficient to deposit the desired metal thickness.
It is furthermore possible to sorb first the reducing agent and then contact the membrane with the metal salt solution, but it has been found more advantageous to carry out the sorption of the metal salt before contact with the reducing agent as this makes it possible to obtain better adherence between the metal film and the membrane.
The presorbed amphoteric compounds have been found instrumental in producing a more finely dispersed and uniform deposition of the first metal layers, which is essential to obtaining good and continuous coverage of the membrane surface to be coated and an exceptionally durable bond between the membrane and the metal layer. During the repeated deposition of the additional metal layers, the sorbed groups become progressively lost in the aqueous solution and practically none remains after a final soaking and rinsing of the coated membrane in water.
The metal salts utilized may give rise, in solution, to positive or negative metal complexes. The preferred salts are, for example,
Palladium chloride (PdCl 2 ) dissolved in diluted HCl to give the anionic complex PdCl 4 -- ;
Palladium diamine-dinitrate (PD(NH 3 ) 2 (NO 2 ) 2 ) dissolved in diluted ammonia or NH 4 Cl saturated solution to give the cationic complex Pd(HN 3 ) 4 ++ ;
Palladium acetate (Pd(CH 3 COO) 2 ) dissolved in water to give the anionic complex PtCl 6 -- ;
Hexachloroplatinic acid (H 2 PtCl 6 ) dissolved in water to give the anionic complex PtCl 6 -- ;
Platinum diamine-dinitrate (Pt(NH 3 ) 2 (NO 2 ) 2 ) dissolved in diluted ammonia or saturated NH 4 Cl solution to give the cationic complex Pt(NH 3 ) 4 ++ ;
Nickel chloride (NiCl 2 ) dissolved in water to give Ni ++ ;
Nickel sulphate dissolved in water to give Ni ++ ;
Other reducible metal salts or solutions may be used as well for the process of the invention. The reducing agents utilized may be of cationic type, such as, for example, hydrazine, hydroxylamine, formamide and its derivatives, oxalic acid, alkali metal borohydrides and the like, or of the anionic tupe as, for example, acetic acid, citric acid, sodium hypophospite and its derivatives, or of the amphoteric type, such as acetaldehyde or formldehyde.
According to the method of the present invention, porous films are provided which are highly adherent to the membrane surface. In fact, by modifying the charge distribution on the membrane surface, as described above, an even and fine metal distribution is achieved and therefore a lower quantity of metal is required to produce films exhibiting a good electrical continuity and adherence degree.
Examples of some suitable metals include nickel, silver, cobalt, gold, rhenium and preferably metals of the platinum group. Mixtures of metals can be employed when desired.
According to a preferred embodiment of the invention, palladium is deposited as the first coating on the membrane. It has been found that by using palladium, electrically continuous films are provided with a minimum quantity of deposited metal compared with other noble metals, such as platinum and iridium. Uniform and continuous films have been provided with palladium quantities lower or equivalent to 4 grams per square meter of surface being contacted. This improvement can be obtained at least to a substantial degree even without the pretreatment with the sulphamic acid or other amphoteric compounds as described above.
It has been found that, in order to improve the catalytic activity, especially as regards hydrogen discharge, the palladium deposit may be advantageously activated by depositing, such as by chemical vapor deposit, cathode sputtering or galvanic techniques, a further coating onto the palladium of a metal capable of providing an electrode surface such as platinum, nickel and cobalt or a coating of a conductive metal sulphide such as nickel sulphide, nickel polysulphide, cobalt sulphide, palladium sulphide or palladium polysulphide. In such an arrangement the palladium acts as the intermediate bonding layer between the electrode structure and the membrane surface.
The catalytic properties of the porous metal layer, preferably a platinum group layer and most preferably palladium, can be further improved by the changing of the metal grain size from a coarser to a finer one, by contacting the metal layer with an amalgam in the presence of water, preferably a mercury amalgam containing minor amounts of an alkali, such as about 0.001% to 0.1% by weight of sodium or lithium or an ammonium amalgam containing from 0.001% to 0.1% of ammonium. The treatment can also be with molten alkali metal or other liquid compositions containing alkali metal in liquid form. The treatment is generally for about 10 to about 60 seconds at temperatures lower than about 25° C.
During the mercury amalgam or liquid metal treatment of palladium, the color of the palladium deposit changes from silver-grey to opaque black, indicating the transformation of the deposit grain size.
Platinum or nickel deposition onto the palladium layer may be effected via chemical deposition, by soaking the membrane, coated with the adherent layer of palladium, in an aqueous solution of H 2 PtCl 6 or NiCl 2 .6H 2 O, respectively, and then contacting with a reducing agent such as soaking in an aqueous solution of hydrazine, NaBH 4 , or NaH 2 PO 2 for a few seconds, and repeating the operation for a number of times to obtain the desired amount of deposit.
Nickel sulphide is galvanically deposited by cathodically polarizing the palladium film which may also be previously coated with a thin nickel layer in an aqueous solution of Na 2 S 2 O 3 and NiCl 2 by means of a counter-electrode, preferably made of nickel, carrying out the electrolysis at a cathodic current density in the range of about 10 to about 80 A/m 2 at a temperature between about 40° and 60° C. under vigorous stirring of the electrolytic bath.
Advantageously, the nickel sulphide deposit may be converted at least partially to nickel polysulphide (NiS 1+x where x>0) by exposing the deposit to a sulphidizing atmosphere of O 2 containing sulphidizing amount (e.g. about 10 to 90% volume) of sulphidizing agent such as H 2 S. The treatment is usually for about 20 to 60 minutes. The color of the deposit turns from glossy black, which is the color of nickel sulphide (NiS) to opaque black, which is the color of nickel polysulphide (NiS 1+x ).
Palladium sulphide deposition onto the metal layer adherent to the membrane surface may be galvanically effected in a palladium complex salts bath containing a soluble reducible compound, such as a sulphate or thiosulphate, carrying out the electrolysis at a current density in the range of about 50 to about 300 A/m 2 at a temperature between about 50° and about 60° C. by cathodically polarizing the palladium film.
Preferably, the electrolytic bath is an aqueous solution containing:
from about 50 to 100 g/l sodium sulphate;
from about 10 to 20 g/l of palladium acetate or palladium iodide;
from about 1 to 5 g/l of sodium acetate.
Advantageously, also the palladium sulphide deposit may be converted at least partially to palladium polysulphide (PdS 1+x where x>0) by exposing the deposit to a sulphidizing atmosphere of O 2 containing sulphidizing amount (e.g.--about 10 to 90% by volume) sulphidizing agent such as H 2 S. The treatment is usually for about 20 to 60 minutes.
Preferably, the palladium bonding layer preformed onto the membrane is between about 4 and about 10 g/m 2 , more preferably between about 4 and about 6 g/m 2 , while the catalytic layer, constituted by at least one material belonging to the group of Pt, Ni, NiS, NiS 1+x , PdS and PdS 1+x , applied onto the palladium layer, is between about 10 and about 30 g/m 2 .
As already discussed above, in order to improve the degree of adherence of the palladium layer onto the membrane surface, the surface itself is previously roughened. A particularly suitable technique comprises sandblasting the membrane surface, previously soaked in water, with substantially spheroidal quartz particles, having a mesh size between 100 and 200 mesh.
The electrode constituted by the palladium porous layer, applied onto one side of the ion exchange membrane, whether or not activated by means of a further catalytic material top deposit, such as platinum, palladium sulphide, nickel, nickel sulphide, may act either as the cathode or the anode of the electrolysis cell. Moreover, the membrane may be coated, during the above mentioned process, on both sides to form the composite system anode-membrane-cathode, particularly suitable for water electrolysis.
In electrolysis of halides, such as for example sodium chloride, the electrode of the present invention preferably constitutes the cell cathode. The anode may be constituted by a valve metal screen, preferably titanium, coated with a layer of non-passivatable material resistant to the anodic conditions, such as, for example, an oxide or mixed oxide of at least one metal belonging to the platinum groups, preferably a ruthenium and titanium mixed oxide with a ratio between the two metals between about 2:1 and about 1:2 which may also contain minor amounts of other metal oxides.
Otherwise, the anode may be composed of a porous layer of oxide particles embedded in the anodic surface of the membrane such as polytetrafluoroethylene, according to the known technique which includes mixing the catalytic powder with the polymer powder and subsequent hot-pressing of the mixture or of a preformed decal film, onto the membrane surface.
Electric current distribution to the electrodes applied onto the membrane surface is provided by pressing against the electrodes suitable metal screens or metal grids which ensure a great number of contact points distributed all over the electrodes surface and by connecting the grids, by means of suitable connectors external to the cell, to the electric current course.
A particularly advantageous embodiment of these cells is widely described in our Italian Patent Application No. 24919 A/79 filed on Aug. 3, 1979, whose description is incorporated herein by reference.
In order to better illustrate the invention, some practical examples of typical embodiments of the present invention are herewith reported. It must be understood, however, that the invention is not limited to these specific embodiments.
EXAMPLE 1
Several samples of a perfluorosulphonic acid membrane available from E. I. DuPont De Nemours under the trade designation Nafion 315 are previously soaked in boiling water for 2 to 3 hours. Nafion 315 is a laminate comprising a layer of Nafion EW 1500 and a layer of Nafion EW 1100 on a teflon screen acting as mechanical strengthener. The hdyrated membranes are then disposed on a rigid support, suitably protected by a frame laid on the membrane edges, and sand-blasted with quartz particles having a mesh size between 100 and 200 mesh, on the sides to be coated with the electrodic layer.
The membranes are conditioned by soaking for several hours in boiling saturated aqueous sodium salt solution (e.g. NaCl or Na 2 SO 4 ) and then rinsed with deionized water.
After these treatments the membrane surfaces which are not to be coated with the metal deposit are brushed with a mixture of flax oil, glycerine and ethylene glycol in order to make them water-repellent.
The membranes are soaked in a water solution containing about 10 g/l of sulphamic acid (NH 2 SO 3 H) for about 10 to 30 minutes.
The membranes are then immersed in a water solution containing about 5 g/l of PdCl 2 , acidified with HCl up to complete solubility, for about 15 minutes and then in an aqueous solution of hydrazine containing 10% by volume of hydrazine for about 15 minutes and then rinsed with deionized water, repeating these operations for 2 to 4 times to obtain a negligible electric resistivity between two laterally spaced points on the palladium coating.
The electrode membrane systems thus prepared are designated with A.
EXAMPLE 2
One electrode-membrane system of the type A, comprised of the membrane coated on one side with a metal palladium deposit of about 10 g/m 2 (grams/square meter), prepared according to the procedure of Example 1, is further treated by contacting the palladium layer with mercury-sodium amalgam, having a sodium content of 0.001% by weight, in an aqueous medium for three individual periods of about 10-15 seconds.
After rinsing, the palladium deposit assumes an opaque-black color; the membrane electrode thus prepared is designated with B.
EXAMPLE 3
Other electrode-membrane systems of the type A, prepared according to the procedure of Example 1, wherein the palladium deposit is about 10 g/m 2 , are further treated, as follows, in order to deposit palladium sulphide onto the palladium layer adherent to the membrane.
The palladium layer deposited onto the membrane is cathodically polarized with respect to a platinum counter-electrode (anode) in an aqueous deposition bath containing about 10 g/l of Na 2 S 2 O 3 .5H 2 O; about 53 g/l (as metal palladium ion) of H 2 Pd(CH 3 COO) 3 or K 2 PdI 4 .
The electrolysis conditions are as follows:
temperature: 40÷65° C.
cathodic current density: 100 A/m 2
mechanical stirring of the electrolytic bath.
A palladium sulphide deposit of about 10 to 12 g/m 2 is obtained in about 2 hours. The deposit color is glossy black. The membrane-electrode systems thus prepared are designated with C.
EXAMPLE 4
A membrane-electrode system prepared according to the procedure of Example 3 is furthermore treated in order to convert at least partially the palladium sulphide layer to polysulphide (PdS.sub.(1+x) where x>0), by immersing the system in an aqueous bath containing about 20 g/l of (NH 4 ) 2 S, maintained at a temperature in the range of about 30° to about 35° C. and bubbling a mixture of H 2 S and O 2 (50:50 by volume) through the bath.
After 20 to 25 minutes, the deposit color turns from the glossy black of the PdS deposit to the dull black indicative of PDS.sub.(1+x) where x>0.
The membrane-electrode system is designated with D.
EXAMPLE 5
Other membrane-electrode systems of the type A, prepared according to the procedure of Example 1 and characterized by a metal palladium deposit of about 5 g/m 2 are further treated in order to deposit a nickel layer onto the palladium layer adherent to the membrane.
Chemical deposition of the nickel layer is carried out by immersing the membrane-electrode systems in an aqueous bath containing reducing agent insertion to convert to Ni:
NiCl 4 : 50 g/l
NiSO 4 : 50 g/l
H 3 BO 3 : 10 g/l
NaH 2 PO 2 : 80 g/l
and maintained at a temperature between about 90° and about 95° C. for about 30 to about 35 minutes.
The electrode membrane systems are rinsed in water. Deposits are obtained of about 45 g/m 2 exhibiting a glossy grey color. The systems thus produced are designated with E.
EXAMPLE 6
Some electrode-membrane systems of the type E, produced according to the procedure of Example 5, are treated to deposit a nickel sulphide layer.
The nickel sulphide layer is galvanically deposited by cathodically polarizing the layer of palladium (5 g/m 2 ) and nickel (35 g/m 2 ) adherent to the membrane with respect to a nickel counter-electrode (anode) in an aqueous electrolytic bath containing:
Na 2 S 2 O 3 .5H 2 O: 10 g/l
H 2 Pd(CH 3 OO) 3 : 53 g/l as metal Pd
maintained at a temperature between about 40° and about 60° C. The cathodic current desnsity is about 150 A/m 2 .
A deposit of about 19 g/m 2 of nickel sulphide, exhibiting a glossy black color, is obtained after two hours.
The membrane-electrode systems thus prepared are designated with F.
EXAMPLE 7
A membrane-electrode system of the type F, prepared according to the procedure of Example 6, is further treated in order to convert at least part of the nickel sulphide layer to nickel polysulphide (NiS.sub.(1+x) where x>0) by immersing the system in an aqueous bath containing 20 g/l of (NH 2 ) 2 S maintained at 30°-35° C. and by bubbling a mixture of H 2 S and O 2 (1:1 by volume) through the bath.
After 35 minutes, the membrane-electrode system is withdrawn and rinsed in water. The deposit has a dull-black color indicating the transformation of nickel sulphide to nickel-polysulphide, at least in the upper layer.
The membrane-electrode system thus prepared is designated with G.
EXAMPLE 8
A membrane-electrode system of the type A, prepared according to the procedure of Example 1, and characterized by a metal palladium deposit of about 10 g/m 2 , is further treated in order to deposit a thin layer of platinum onto the palladium layer. Chemical deposition if effected by brushing an aqueous solution containing about 100 g/l of H 2 PtCl 6 mixed with ethyl alcohol in a volumetric ratio of 1:1.
After evaporation of the solution applied, the palladium layer impregnated with platinum salt is brushed with an aqueous solution containing about 10 g/l of hydrazine (N 2 H 4 ).
A deposit of about 0.5 g/m 2 of metal platinum is obtained on the palladium layer by repeating the above operations twice.
The membrane-electrode system thus prepared is designated with H.
EXAMPLE 9
The electrode-membrane systems prepared according to the above examples, after suitably removing the hydrophobic layer applied onto the uncoated surfaces (see Example 1) are kept immersed in diluted caustic soda in order to prevent membrane dehydration, are tested in a laboratory cell for sodium chloride electrolysis.
The cell is provided with an anode connected to the positive pole of the electric source, constituted by an expanded titanium sheet activated with a titanium (55%) and ruthenium (45%) mixed oxide deposit.
The membrane electrode systems are installed with the uncoated membrane facing the anode, while the electrode bonded to the opposite surface of the membrane constitutes the cell cathode.
Electric current is distributed to the cathode by pressing a nickel screen current collector or distributor against the electrodic layer. The current collector is constituted by a thin, 25 mesh, nickel screen, contacting the cathode and a resilient layer constituted by a crimped fabric made of 0.1 mm nickel wire, pressed against the nickel screen by a nickel-plated foraminous steel plate suitably connected to the negative pole of the electric current source.
The membrane provides hydraulic separation between the anodic compartment and the cathodic compartment of the cell.
Saturated brine (300 g/l of NaCl) having a pH between about 6 and about 5.5 is added to the anodic compartment bottom and diluted brine (200 g/l of NaCl having a pH between 4 and 3.5 is withdrawn together with the chlorine produced at the anode, through an outlet placed on top of the anodic compartment.
Caustic soda concentration in the cathodic compartment is maintained at 18% by recycling the catholyte outside the cell and adding water, and removing concentrated caustic soda from the circuit.
The anolyte temperature is kept at about 70° C. Current density is about 3000 A/m 2 . The operating conditions of the membrane-cathode systems are reported on the following table, wherein, for comparison purposes, are reported also the operating conditions of a reference cell equipped with the same type of membrane (Nafion 315) without the cathodic layer and provided with a cathode of a nickel screen in contact with the membrane.
__________________________________________________________________________ Electrodic Caustic Soda Electrodic LayerElectrode- Layer Cell Faradic Chlorides Content Weight LossMembrane Electrode Thickness Voltage Efficiency in Caustic Soda After 200 HoursSample g/m.sup.2 V % ppm mg/m.sup.2__________________________________________________________________________A Pd 10 3.7 85 50 non detectableB Activated Pd 10 3.4 85 60 5C Pd + PdS 5 + 12 3.5 85 40 non detectableD Pd + PdS + PdS.sub.(1 + x) 5 + 12 3.4 85 40 "E Pd + Ni 5 + 35 3.4 85 20 "F Pd + Ni + NiS 5 + 35 + 10 3.1 85 20 "G Pd + Ni + NiS.sub.(1 + x) 5 + 35 + 10 3.1 85 20 "H Pd + Pt 10 + 0.5 3.1 85 30 "Reference -- -- 3.8 85 40 --Cell__________________________________________________________________________
Although the above examples illustrate coating on one side of the membrane and use as a cathode, it is understood that anodes as well can be prepared according to the present invention and that both sides of the membrane can be coated if desired. It is noted from the above table that the practice of the present invention makes it possible to decrease the needed voltage for achieving the same yield as the reference cell which does not contain a cathode layer according to the present invention, but instead includes a nickel screen in contact with the membrane.
While the present invention has been and is described in connection with certain preferred embodiments and modifications thereof, other embodiments and modifications thereof will be apparent to those skilled in the art, and it is intended that the appended claims cover all such embodiments and modifications as are within the true spirit and scope of this invention.
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A gas and electrolyte permeable metal layer is bonded to an ion-permeable membrane by electroless deposition to produce a permeable metal deposit upon the membrane or diaphragm. Advantageously, the membrane surface to be coated is pretreated with an amphoteric material. Thereafter, the treated surface is treated to deposit the coating. Typical metals deposited include platinum group metals, iron group metals, such as nickel, cobalt and others including gold and silver. The coatings are very thin, rarely in excess of about 50 to 100 microns.
The coated membrane may be installed in an electrolytic cell used for producing chlorine and alkali by electrolysis of alkali metal chloride with the coating serving as one electrode and another opposed electrode on or adjacent to the opposite side of the membrane. It may also be used in water electrolysis and for other purposes.
The coatings may be thickened by depositing other coatings of the same or different composition by suitable coating techniques.
Especially adherent coatings are obtained when the metal deposited upon the pretreated surface is palladium metal or a mixture of palladium with another metal. Thickening coatings deposited upon such a porous palladium coating are found to have superior adherence and durability. The metal layer may be soaked or contacted with an alkali metal or an amalgam in presence of water to modify its crystal structure or grain size, if desired.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an automatic sheet feeding system for automatically feeding cut sheets to a recording unit for image recording on the cut sheets.
2. Description of the Prior Art
In general, recording apparatus uses a continuous sheet such as a fan-fold sheet, or separate cut sheets. In case of continuous sheet, once it is loaded, no further sheet loading is required. On the other hand, cut sheets have to be fed into the recording apparatus one by one and an automatic sheet feeding mechanism is desirable.
In such automatic sheet feeding mechanism, for example a cut sheet feeder employed in conventional printers as shown in FIG. 1, the sheet feeding is effected by rotating a feed roller 201 as by a motor, while the sheet discharge is effected by a discharge roller 204 linked with a sheet advancing roller 202 in the printer. More specifically, in FIG. 1, the sheet advancing roller 202 is linked with the discharge rollers 204 for example through an unrepresented belt whereby the latter roller is rotated by the former. In such case a cut sheet 203 is fed toward the discharge rollers 204 with the progress of the printing operation from the contact point of a first pinch roller 206 and the advancing roller 202, while sheet discharge is effected by pinching the sheet with two discharge rollers 204. There are also shown a printer 205, an automatic sheet feeder 210, a recording head 212, and a second pinch roller 214.
The sheet finally leaves the discharge rollers 204 and is discharged to a tray 208. In this operation, however, sheet jamming may occur as the lower end of the sheet 203 tends to be retained between the discharge rollers 204.
Also in case the discharge rollers 204 are rotated by the sheet advancing roller 202, they have to be rotated even during mere sheet advancement or sheet discharge, thus requiring a large motor with a significant power loss.
Also the continuous rotation of the sheet advancing roller and the discharge rollers may result in a slack or a skewed advancement of the cut sheet unless these rollers are mutually synchronized, and such synchronization leads to a complicated structure and an elevated cost of the apparatus.
In case a cut sheet feeder is adopted, it is still desirable that the operator can manually load cut sheets one by one into the recording apparatus. For this purpose there are conventionally provided an exclusive selector switch for selecting an automatic sheet feed mode and a manual sheet feed mode and an aperture for inserting a cut sheet, and the operator is required to insert a cut sheet into the aperture after the selector switch is properly manipulated. In such structure, however, there results a danger of the cut sheet being manually inserted without proper shifting of the selector switch.
Also the conventional cut sheet feeder is provided with an exclusive sheet detecting switch, and the recording apparatus controls the feeder and determines the timing of sheet feeding in response to the detection by the switch. Such method not only requires an exclusive detecting switch but also an exclusive signal processing program responding to the switch in the recording apparatus, thus increasing the load to the control system therein.
Besides such conventional cut sheet feeder is provided with a feed start switch and other switches. Such arrangement not only requires exclusive switches but again needs exclusive programs for such switches in the recording apparatus, thus increasing the load of the control system thereof.
Furthermore, such conventional cut sheet feeder is often equipped with exclusive alarm means for indicating the absence of recording sheet or sheets jamming. In such conventional feeder, exclusive programs for activating such alarm means have to be provided in the recording apparatus, thus increasing the load to the control system thereof.
Furthermore, a conventional cut sheet feeder is provided with separate switches respectively for detecting the absence of recording sheets and sheet jamming. Such structure, involving plural detecting switches, requires a complicated circuitry increasing the load on the control system of the recording apparatus.
Also the conventional cut sheet feeder is provided with an exclusive switch for detecting sheet jamming, but the presence of such a switch complicates the structure and increases the load on the control system of the recording apparatus.
Furthermore the conventional cut sheet feeder is either unable to detect the absence of recording sheets or requires an exclusive detecting switch for such detection, which inevitably complicates the structure and increases the load on the control system of the recording apparatus.
Furthermore, in the conventional structure, the recording apparatus is provided with a motor for rotating the sheet advancing roller while the cut sheet feeder is provided with a motor for rotating a sheet feeding roller or a sheet discharge roller, and these motors are simultaneously in motion for a certain period. Consequently there is required a power source of a large capacity for driving these motors.
SUMMARY OF THE INVENTION
An object of the present invenion is to provide an automatic cut sheet feeding system for use in a recording apparatus, capable of securely discharging cut sheets.
Another object of the present invention is to provide an automatic cut sheet feeding system that is capable of avoiding a power loss in motors which enables the use of small motors.
Still another object of the present invention is to provide an automatic cut sheet feeding system in which a sheet discharge roller need not be synchronized with the sheet advancing operation in the recording apparatus, so that the structure can be simplified.
Still another object of the present invention is to provide an automatic cut sheet feeding system enabling secure feeding of cut sheets by manual insertion.
Still another object of the present invention is to provide an automatic cut sheet feeding system in which a sheet detecting switch of the recording apparatus is also used as the sheet detecting switch for the cut sheet feeder.
Still another object of the present invention is to provide an automatic cut sheet feeding system in which an operation switch of the recording apparatus is also utilized as the operation switch for the cut sheet feeder.
Still another object of the present invention is to provide an automatic cut sheet feeding system in which alarm means of the recording apparatus is also utilized as the alarm means for the cut sheet feeder.
Still another object of the present invention is to provide an automatic cut sheet feeding system in which a switch is utilized both for detecting the absence of recording sheets and for detecting sheet jamming.
Still another object of the present invention is to provide an automatic cut sheet feeding system in which a sheet detecting switch of the recording apparatus is utilized also as a sheet jam detecting switch for the cut sheet feeder.
Still another object of the present invention is to provide an automatic cut sheet feeding system in which a detecting switch of the recording apparatus is also utilized as a switch for detecting the absence of the recording sheet in the cut sheet feeder.
Still another object of the present invention is to provide an automatic cut sheet feeder which allows the use of small motors, thereby enabling reduction of the capacity of the power source.
The foregoing and other objects of the present invention, and the advantages thereof will become fully apparent from the following description.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic view of a conventional printer and cut sheet feeder;
FIG. 2 is a perspective view of a sheet discharge mechanism in an automatic cut sheet feeder constituting an embodiment of the present invention;
FIGS. 3 to 6A-6C illustrate another embodiment of the present invention and respectively are a lateral cross-sectional view, a plan view, a partial enlarged view of the essential part and a schematic view showing the function of a sheet discharge roller of an automatic cut sheet feeder;
FIGS. 7 to 9 illustrate a sheet advancing roller and a one-way clutch and respectively are a cross-sectional view, a perspective view and another perspective view;
FIG. 10 and insuring drawings illustrate still another embodiment, wherein;
FIG. 10 is a lateral view of an automatic cut sheet feeder constituting another embodiment;
FIG. 11 is a partially cut-off perspective view of FIG. 10;
FIG. 12 is an elevation view of FIG. 10;
FIG. 13 is a cross-sectional view of FIG. 10;
FIG. 14 is a lateral cross-sectional view thereof;
FIGS. 15A and 15B show a block diagram of the circuitry for either embodiment;
FIGS. 16A to 16C, 17A to 17C, 18A to 18C, and 19A to 19B are flow charts;
FIGS. 20A to 20H are schematic views showing a feed process for a cut sheet; and
FIG. 21 is a timing chart.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Now the present invention will be clarified in detail by embodiments thereof shown in the attached drawings.
FIG. 2 is a schematic view of a sheet discharge mechanism embodying the present invention, wherein a support plate constituting a part the housing of an unrepresented automatic cut sheet feeder is provided with three pairs of guide ribs 2 in parallel manner, and discharge rollers 8, mounted on a roller shaft 6 are provided in such a manner that each discharge roller 8 faces a groove 4 between corresponding pairs of guide ribs 2 and the external periphery 12 of the discharge roller 8 is tangential to a plane formed by the upper surfaces of the guide ribs 2.
The function of the above-described mechanism is as follows. A cut sheet 14 is advanced in a direction M by a sheet advancing roller of an unrepresented recording apparatus or printer, and when the discharge rollers 8 are activated, the cut sheet is further advanced in the direction M by the rotation of the rollers 8, while being pinched between the rollers 8 and the guide ribs 2.
Also as shown in FIG. 2, unrepresented lateral boards of the automatic cut sheet feeder are provided with guide grooves 16 which are extended in a direction substantially perpendicular to the sheet discharging direction M and in which the discharge roller shaft 6 is rendered movable, whereby the discharge rollers 8 are moved in a direction G only during the sheet discharging operation to pinch the cut sheet 14 between the peripheries 12 of the discharge roller 8 and the upper surfaces 10 of the guide ribs 2, but are lifted in a direction H by unrepresented springs in other instances. FIGS. 3 to 5 illustrate an example of the automatic cut sheet feeder with the guide grooves in the lateral boards as an embodiment of the present invention, and are, respectively, a schematic lateral cross-sectional view, a schematic plan view and a partial enlarged view of an essential part.
As shown in FIG. 3, the automatic cut sheet feeder 18 is detachably mounted on a printer 20, and is provided with a motor 22 rotatable in forward or reverse direction, a sheet feeding roller 24 and a sheet discharge roller 8, both of which are driven by the motor 22. More specifically, as shown in FIG. 4, a first belt 34 is provided between a motor pulley of a motor shaft 26 and a first sheet feed pulley 32 of a sheet feed roller shaft 30, and a second belt 40 is provided between a second sheet feed pulley 36 of the sheet feed roller shaft 30 and a sheet discharge pulley 38 of a sheet discharge roller shaft 6. Each lateral board 42 of the automatic cut sheet feeder 18 is provided with a guide groove 16 (FIG. 5) which extends in a direction substantially perpendicular to the discharge direction of the cut sheet 14 and in which the discharge roller shaft 6 is slidably supported.
In FIG. 3 there are also shown a stack of cut sheets 44; a pressure plate 46 for supporting and pressing the sheet stack 44 against the sheet feed roller 24; a separating finger 48; a sheet feeding slot 50; a sheet advancing roller 52 functioning also as a platen in the printer 20; first and second pinch rollers 54, 56; and a sheet discharge slot 58. In FIG. 4 there are shown swinging levers 60 rotatably supporting the sheet discharge rollers 8; and a spring 62.
A front plate 64 (FIG 5) of the automatic cut sheet feeder 18 of the above-described structure is provided with three pairs of guide ribs 2, and the sheet feed roller shaft 30 is so positioned that each of the sheet feed rollers 24 faces a gap between paired ribs 2.
Between each of the sheet feed rollers 24 and the sheet feed roller shaft 30 there is provided an unrepresented one-way clutch for the following purposes:
(1) In the normal sheet feed, the rotation of the sheet feed roller shaft 30 is directly transmitted to the sheet feed rollers 24;
(2) While the motor 22 is deactivated for printing operation on the printer, the cut sheet is advanced by the sheet advancing roller of the printer but the trailing end of the cut sheet is still in contact with the sheet feed rollers 24 to rotate the same in the forward direction by friction, but the forward rotation is not transmitted to the sheet feed roller shaft; and
(3) In the sheet discharge, the motor 22 is reversed so that the sheet feed roller shaft 30 is also rotated in the reverse direction, but the reverse direction is not transmitted to the sheet feed rollers 24.
In summary, in the above-described embodiment, the pressure plate 46 constitutes a sheet storage unit for the sheet stack 44. As a consequence of forward rotation of the motor 22, sheet feed means composed of sheet feed rollers 24, supplies a cut sheet between a sheet advancing roller 52 and pinch rollers 56, 54 constituting sheet advancing means of the printer. The sheet advancing roller 52 and pinch rollers 56, 56 advance the cut sheet 14 toward the discharge roller 8 through a position in front of a recording head 70 that effects recording on the sheet. After recording by the recording head, the cut sheet is pinched by the discharge rollers 8 and guide ribs 2 for discharge in the upward direction, and is disposed in such a manner that its lower end lies on the upper slanted portions of the ribs 2. In this manner the sheet is stored in a discharged sheet storage unit composed of the front plate 64 and the upper slanted portions of the guide ribs 2.
In the following there will be given a detailed explanation on the function. In the sheet feeding operation, the motor 22 is rotated in a direction A shown in FIG. 5, whereby the sheet discharge rollers 8 are rotated, through the first belt 34, first sheet feed pulley 32, second sheet feed pulley 36 and second belt 40, in a direction E, and at the same time the sheet discharge rollers 8, an intermediate lever 60 and second belt 40 are integrally lifted in a direction H by the tension of the second belt 40, as shown in FIG. 6(A).
In this state the sheet feed roller shaft 30 is rotated in a direction C, and the rotation is transmitted to the sheet feed rollers 24 by the function of the one-way clutches.
By the rotation of the sheet feed rollers 24 in the direction C, an uppermost sheet in the sheet stack 44 is disengaged from the separating finger 48, and, due to rotation of the sheet feed rollers 24, is advanced to a contact point between the sheet advancing roller 52 and the second pinch roller 56 of the printer 20. When the leading end of the sheet 14 reaches the contact point, the motor 22 is stopped and the sheet advancing roller 52 is driven by an unrepresented driving source whereby the sheet 14 advances between the first pinch roller 54 and sheet advancing roller 52, printed in the printer 20 and is forwarded to the discharge slot 58.
Though the motor 22 is stopped during this operation, the trailing end part of the sheet 14 remains in contact with the feed rollers 24 to rotate the same in a direction C by friction with the sheet 14 during advancement thereof; however, because of the operation of unrepresented one-way clutches, the sheet feed roller shaft 30 is not rotated and the feed rollers 24 are idling.
When the trailing end of the sheet 14 reaches the contact point between the sheet advancing roller 52 and the first pinch roller 54, said advancing roller 52 is stopped and the motor 22 is put into reverse rotation in a direction B. Said rotation is transmitted through the first belt 34, first sheet feeding pulley 32, second sheet feeding pulley 36 and second belt 40 to the discharge pulley 38 whereby the sheet discharge rollers 8 are rotated in a direction F. In response to said rotation in the direction F, due to the tension of the second belt 40, the sheet discharge rollers 8, intermediate lever 60 and second belt 40 are integrally lifted in a direction G shown in FIG. 5. In this state, as shown in FIG. 6(B), the sheet 14 is present between the upper faces of the ribs 2 and the peripheries 12 of the sheet discharge rollers 8 whereby the sheet discharge rollers 8 press and advance the sheet 14. When the trailing end of the sheet 14 comes into contact with the sheet discharge rollers 8 at the end of advancement of the sheet 14 (FIG. 6(C)), the sheet discharge rollers 8 descend, by the weight thereof, toward the lower end G of the guide groove 16 whereby the sheet discharge roller shaft 6 is stopped at the lower end of the guide groove 16. The trailing end of the sheet 14 is smoothly discharged by the descent of the sheet discharge rollers 8.
During the discharge of the sheet 14, the sheet feeding roller shaft 30 is also rotated in the reverse direction D, but the sheet feeding rollers 24 are not rotated by the function of the one-way clutches, thus preventing the reverse advancement of the sheet.
The selection of forward or reverse rotation of the motor 22 and the activation of the sheet advancing roller 52 are achieved by a control unit in response to signals from unrepresented sensors.
In the foregoing embodiment the power transmission from the motors is achieved by belts, but it is naturally possible to employ gears or other means.
The foregoing embodiment employs three pairs of ribs and three sheet discharge rollers, but it is naturally possible to employ these elements in other numbers.
FIGS. 7 to 9 show details of the sheet feeding rollers 24 and one-way clutches. The sheet feeding roller 24 is composed of a molded member 84 and a rubber member 86 for contact with the sheet, and the molded member 84 is rendered rotatable to the sheet feeding roller shaft 30. Around the molded member 84, there is provided a first spring clutch 80 of a diameter slightly smaller than the external diameter of the molded member 84. Because of such diameter relationship, the first spring clutch 80 is radially compressible against the molded member 84. An end of the first spring clutch 80 engages with a part 88 of the automatic cut sheet feeder (FIG. 8) while the other end is left free.
As viewed the left end of the molded member 84 is notched as it 90. Around the sheet feeding rolling shaft 30 there is provided a second spring clutch 82, as shown in FIG. 9. The diameter of that clutch is also slightly smaller than the external diameter of the sheet feeding roller shaft 30. The second spring clutch 82 is radially compressible against the shaft 30. The second spring clutch 82 has a radially extended end 92 engaging with the notch 90 of the molded member 84 as shown in FIG. 7, and the other end is left free.
As shown in FIG. 8, the first spring clutch 80 allows the sheet feeding roller 24 to rotate only in one direction. When the sheet feeding roller 24 starts to rotate in the reverse direction I, the first spring clutch 80 is tightened, with an end thereof fixed to a part 88 of the automatic cut sheet feeder, to lock the sheet feeding roller 24. However the sheet feeding roller 24 can freely rotate in a direction J as the first spring clutch 80 is loosened.
The second spring clutch 82 transmits the rotation of the sheet feeding roller shaft 30 in only one direction to the sheet feeding roller 24. When the sheet feeding roller shaft 30 is rotated in the forward direction K, the second spring clutch 82 is tightened to transmit the rotation to the sheet feeding roller 24. If the sheet feeding roller 24 is rotated in the forward direction J while the roller shaft 30 is stopped, the second spring clutch 82 is loosened so that the roller shaft 30 is not rotated. Also in case the sheet feeding roller shaft 30 is counter rotated in a direction L, the first spring clutch is tightened but the second spring clutch is loosened, so that the molded member 84, and consequently the sheet feeding roller 24 is not rotated.
In FIG. 10, showing the entire structure of a cut sheet feeder, a stack 101 of cut sheets shown placed between a paper holder 102 and a front cover 103 freely openable in a direction of the arrow from said paper holder 102, and the upper end of the stack 101 is supported by a hopper 104.
In the lower part of the cut sheet feeder there is formed a feed and discharge unit powered by a motor 105. In FIG. 11, a stepping motor 105 is shown mounted in a left rear position, and linked to a sheet feeding pulley 108 through a motor pulley 106 and a timing belt 107. The sheet feeding pulley 108 is fixed to and rotates always integrally with a sheet feeding shaft 109 rotatably supported by two lateral plates of the cut sheet feeder. The sheet feeding shaft 109 supports, through one-way clutches 110, 111, sheet feeding rollers 112, 113 which rotate only when the motor 105 is rotated in one direction.
The sheet feeding shaft 109 rotatably supports a lever 115 an end of which is supported by a spring 114 to suspend the other end thereof. Though only one lever at the left-hand side is illustrated, there is also provided a similar lever 115 at the right-hand side. These paired levers 115 are both rotatably supported by the sheet feeding shaft 109 and are rotatably supported, at the other end by a sheet discharge shaft 116.
On both ends of the sheet discharge shaft 116, close to the levers 115 there are fixed sheet discharge pulleys 117, powered through timing belts 119 from small pulleys 118 (FIG. 10) integrally rotating with the sheet feeding pulley 108. In this way, pulleys 117 always rotate with the motor 105. The sheet discharge shaft 116 supports sheet discharge rollers 120 that are affixed thereto.
FIG. 12 is a view of the cut sheet feeder seen from the front. At the upper left end of the paper holder 102, a release lever 121 is rotatably mounted about an axis 122. The release lever 121 is provided with a cam face 121a and engages with a release arm 124 rotatably mounted about an axis 123. A lateral support member 125 for supporting the left lateral face of the stack 101 of the cut sheets engages the release arm 124 and is biased toward the stack 101 by a spring 126. On the opposite side there is provided a paper guide member 127 for supporting the right lateral face of the stack 101 of the cut sheets.
In the above-described structure, when the release lever 121 is pulled toward the front in FIG. 12, the lateral support member 125 is moved in a direction N through the release arm 124, whereby the stack 101 of the cut sheets is released from restraint in the lateral direction. In this manner the removal or replacement of the stack 101 is rendered possible.
The lower end of the sheet stack 101 is supported, at both ends thereof, by separating fingers 128, 129 similar to those employed in a sheet cassette of a copier.
Between the sheet discharge pulley 117 and the lever 115 there are provided a felt member 130 of high friction and a spring 131 for biasing the felt member 130 toward the lever 115, in order to bias the lever 115 to a determined position by the rotation of the motor 105 as will be explained later.
FIG. 13 is a cross-sectional view of the cut sheet feeder, wherein the cut sheet stack 101 is placed on an intermediate plate 132. A spring 133 presses the lower part of the intermediate plate 132 toward the sheet feeding rollers 112, whereby an uppermost sheet in the stack 101 is always in contact with the sheet feeding rollers 112.
The sheet discharge rollers 120 are positioned above guide ribs 134 for the discharged sheet and are movable in a direction O or P.
When the motor 105 is rotated in a direction Q in FIG. 10 in the above-described cut sheet feeder, the one-way clutches 110, 111 are activated to rotate the sheet feeding rollers 112, 113 in a direction Q1 shown in FIG. 13, thereby advancing an uppermost sheet of the stack 101 toward a printer located below. The rotation of the motor 105 shifts the levers 115 in the direction O to lift the sheet discharge rollers 120 from the guide ribs 134, so that the cut sheet 135 discharged from the printer cannot be pushed back into the printer in spite of the rotation of the sheet discharge rollers 120 in a direction R1 (FIG. 13).
When the motor 105 is rotated in a direction R in FIG. 10, the sheet feeding rollers 112, 113 are not rotated as the one-way clutches 110, 111 are deactivated. On the other hand, the levers 115 are shifted in a direction r, whereby the discharged cut sheet 135 is pinched between the sheet discharge rollers 120 on the one hand and the guide ribs 134 on the other hand, and is discharged to a discharged sheet tray 136 by the rotation of the sheet discharge rollers 120 in a direction R1. A sheet support member 138, rotatable about an axis 137, presses the discharged cut sheet to form a neat sheet stack on the tray.
In the foregoing there has been explained the function in an automatic sheet feed mode. The cut sheet feeder of the present embodiment is also provided with a manual feed mode, in which the cut sheets are manually supplied.
FIG. 14 shows the manual feed mode wherein the front cover 103 is pulled in a direction S. In this manner, the lower end of the front cover 103 actuates an actuator 139a of a mode switch 139 mounted on the casing of the cut sheet feeder, thus turning on the switch 139. The output signal thereof is transmitted to the printer through an unrepresented cable, thus indicating to the printer that the manual feed mode has been adopted. Also a manual feed slot 140 is formed by the movement of the front cover 103, thus enabling the insertion of a cut sheet. The cut sheet inserted from the manual feed slot is guided to a position between the platen of the printer and the pinch rollers thereof. The details of the printer are the same as in the foregoing embodiment and are therefore not explained further.
ELECTRIC STRUCTURE
FIG. 15 shows the electric connections among the cut sheet feeder, printer 20 and a host computer. The cut sheet feeder is connected, at a connector 151 thereof, to a connector 152 of the printer, and the motor 105 is controlled by drive signals supplied from the printer. The mode switch 139 is also connected, through connectors, to the printer to transmit the state of the mode switch to the printer. The connections relating to the mode switch 139 are made by three lines including a ground line 139b, wherein the state of the mode switch 139 is transmitted by lines 139b and 139d, while lines 139b and 139c are used to indicate whether the connector 151 of the cut sheet feeder is connected to the connector 152 of the printer.
In the printer, a central processing unit (CPU) 153 controls drivers 158, 159, 160 etc. according to a program stored in a ROM 154 and in response to the signals from various sensors 156 (carriage position detecting sensor, ribbon and sensor, temperature sensor etc.) and a sheet end sensor 157 to activate a carriage motor 161, a platen motor 162, a printing head 163 thereby printing the data stored in a RAM 155 on a cut sheet on an unrepresented platen. The CPU 153 also detects the state of the mode switch 139 of the cut sheet feeder, and, in case of the automatic feed mode, activates the motor 105 of the cut sheet feeder through a driver 164, thus feeding new cut sheets from the feeder to the printer and introducing the sheets discharged after printing into the cut sheet feeder.
On the other hand, when the mode switch 139 is positioned at the manual feed mode, the CPU 153 does not activate the motor 105 of the cut sheet feeder but executes printing by activating the carriage motor 161, platen motor 162 and printing head 163 in a process in the absence of the cut sheet feeder.
The aforementioned RAM 155 contains not only an area 155a for storing data transmitted from the host computer 165 but also areas required for program execution of the CPU 153, such as a line feed counter 155b for storing the number of line feeds of the platen motor 162, an RC memory 155c for storing the detection of sheet end by the sheet end sensor 157, an SKEY memory 155d for storing data indicating that either an LF switch, an FF switch (page feed switch) or a PS (paper set) switch has been actuated, a CSF memory 155e for memorizing whether the cut sheet feeder is in operation, a jam memory 155f for memorizing whether sheet jamming has taken place etc.
The printer is further provided with an alarm lamp indicating that the absence of cut sheets has been detected by the sheet end sensor 157, and an on-line lamp 171 indicating whether the printer is in an on-line state in which the printer can accept data from the host computer 165, or in an off-line state in which the printer is unable to accept data.
FUNCTION
FIGS. 16A-16C and 17A-17C show operations of the cut sheet feeder and the printer, and the program for executing these operations is stored in the ROM 154 of the printer. In the following there will be explained for respective cases.
Process in response to turning on of power switch
The content of the RAM 155 is initialized when an unrepresented power switch on the right side face of the printer is turned on in a step S1. More specifically, the P-jam memory 155f, SKEY memory 155d, LF coutner 155b and RC memory 155c are set to "0" and the CSF memory 155e is set to "1" respectively in steps S2-S6. After the initialization, a step S7 detects the output of the sheet end sensor 157 provided in the printer to identify whether cut sheets are present in the printer. The sensor, though not illustrated, is positioned to detect the cut sheet supplied from the cut sheet feeder, immediately before reaching the platen. In case of negative discrimination, i.e. in the presence of cut sheets, the program proceeds to a step S8. The RC memory stores "1" or "0" respectively when the absense or presence of a sheet has been detected, and the discrimination in this case is therefore negative. A succeeding step S9 stores "0" in the CSF memory, which stores "0" or "1" respectively for enabling or disabling the cut sheet feeder. A succeeding step S10 again identifies the state of the RC memory. Since RC memory=0 in this case, an on-line signal is generated in steps S11, S12 to turn on the on-line lamp 171 of the printer to indicate that the printer is ready a printing operation. In this state, the printer awaits the data from the host computer, or preferentially enters an off-line process if the on-line switch is actuated.
On the other hand, in case the step S7 identifies the absence of sheets, there are executed a step S14 for identifying whether the cut sheet feeder is mounted to the printer, a step S15 for identifying whether the cut sheet feeder is in the manual feed mode, and, in case of the automatic feed mode, a step S16 for identifying whether the CSF memory is "0". Since the memory is initialized to "1" at the start of power supply in this case, the program proceeds to a step S17 for setting "1" in the RC memory for indicating the absence of sheets. In case the content of the RC memory is "1", the program proceeds through the steps S8 and S10 to a step S18 to light the alarm lamp 170 in a front panel of the printer, then a step S19 to release an off-line signal and a step S20 to turn off the on-line lamp. Also in the case the on-line switch is actuated in the aforementioned step S13, the program directly jumps to a step S19 without turning on the alarm lamp 170, because the off-line state is merely adopted in this case without any abnormality.
After the off-line process is initiated in this manner, this state is basically retained until either of the LF (line-feed) switch, FF (page-feed) switch and PS (paper set) switch is actuated. Exceptional cases will be explained later.
On-line state
In case the on-line switch is not actuated in the step S13 and data are received from the host computer in a step S21, there are executed a step S22 for identifying whether the data are a line feed signal LF, and a step S23 for identifying whether the data are a page feed signal FF, and, if the discriminations in both steps are negative, a step S24 is executed to activate the carriage motor 161 and the printing head 163 for printing.
On the other hand, in case the step S22 identifies said data as a line-feed signal, a step S25 identifies if the cut sheet feeder is mounted, and, if not, a step S26 rotates the platen motor 162 by a line pitch and a step S27 executes a step increment of the LF counter. On the other hand, if the discrimination in the step S25 is affirmative, a step S28 identifies whether the content of the LF memory is equal to or larger than 100. The formats of the sheet loadable in the cut sheet feeder are such that the sheet end can be sufficiently detected by the sheet end sensor 157 by feeding of 100 lines even for the maximum size. Thus, in case the content of the LF memory is equal to or larger than 100, a step S29 executes another line feed and a step S30 senses the output of the sheet end sensor 157 to identify whether a sheet jamming is present. If the sheet is absent, indicating absence of abnormality, the program returns to the step S6 to repeat the on-line process. On the other hand, if the sheet is present, step S31 to S33 are executed to flash the alarm lamp 170 of the printer and set "1" in the P-jam memory, thus indicating the presence of sheet jamming. The flashing of the alarm lamp 170 continues until the jammed sheet is removed and the sheet end sensor 157 identifies sheet absence, whereupon the program returns to the step S6 while the alarm lamp is continuously lighted.
Upon returning to the step S6 after removal of the jammed sheet, the RC memory is set to "0" and, if the set conditions are not changed, the off-line process is initiated. Then steps S18 to S20 are executed to continue the lighting of the alarm lamp 170, to release an off-line signal instead of the on-line signal and to extinguish the on-line lamp 171, and the program waits in this state until either of the LF, FF and PS switches is actuated.
On the other hand, in case the step S23 identifies the data as the FF signal, a step S34 identifies if the cut sheet feeder is mounted, and, if not, a step S35 is executed to advance the sheet until the end of the page, i.e. the lowest printable line, according to the content of the line feed (LF) memory. In case the cut sheet feeder is mounted and the manual feed mode is not adopted, a step S37 again detects the output of the sheet end sensor 157, and, if the sheet is present, steps S37 to S40 are executed to rotate the platen motor 162 until the content of the LF memory reaches 100 or the sheet end is detected by the sheet end sensor 157 and to increase the content of the LF memory.
Upon detection of the sheet end or the arrival of the content of the LF memory at 100, a step S41 again detects the output of the sheet end sensor 157, and, if the result is negative, indicating the presence of sheet jamming, steps S41 to S44 are repeated to flash the alarm lamp 170 and to set "1" in the P-jam memory. Upon removal of the jammed sheet, the program returns to the step S6 while the alarm lamp 170 continues to be lighted, and the program waits in the off-line state in the same manner as the program return from the step S30.
On the other hand, in the on-line state, the automatic sheet feed operation from the cut sheet feeder to the printer and the sheet discharge operation from the printer to the cut sheet feeder are initiated when a step S71 identifies the absence of sheet. Upon detection of the absence of sheet in the step S71, the program proceeds, according to already set conditions, to a step S42 to set "1" to the CSF memory, and then to a step S43 for identifying whether the content of the P-jam memory is zero. Since the absence of sheet jamming is assumed in this case, the discrimination results are affirmative so that a step S44 rotates the platen motor 162 of the printer by a determined amount to sufficiently discharge the sheet on the platen to the cut sheet feeder, and a step S45 rotates the motor 105 of the cut sheet feeder by a determined amount in the reverse direction to discharge the printed sheet on the sheet tray. Immediately thereafter a step S46 rotates the motor 105 in the forward direction by a determined amount to feed a cut sheet on the sheet feeding tray to the printer. A step S47 rotates the platen motor 162 by an amount corresponding to 16 lines, thereby advancing the cut sheet thus fed to a print start position.
The first sheet feed and sheet discharge are thus achieved in the above-described steps S44 to S47. Then a step S48 detects the output of the sheet end sensor 157 to identify whether the sheet feed and discharge have been correctly effected. If the sheet is detected, indicating a normal state, the program again enters the data processing routine. On the other hand, if the sheet is absent, a step S17 sets "1" in the RC memory and the program enters the off-line process.
Off-line process
In the present embodiment, the off-line state enables an initial sheet setting to the print start position and a sheet setting after a sheet jamming. The off-line state can be divided into a case in which a cut sheet is correctly loaded in the printer and the alarm lamp 170 is turned off, and another case in which the alarm lamp 170 is turned on because of the absence of a cut sheet in the printer or the cut sheet feeder. In case the alarm lamp 170 is turned off, the on-line state can be restored merely by actuating the on-line switch. On the other hand, in case the alarm lamp 170 is turned on, the on-line state can be restored only by sheet setting for example by actuating the FF switch or PS switch.
In the off-line state, upon detection of the actuation of the LF switch in a step S49, steps S50 to S58 are executed to effect a line feed of cut sheet, detection of sheet jamming, storage of sheet jam detection etc. in the same manner as in the case of LF signal detection in the step S22. Then a step S59 sets "1" in the SKEY memory in order to memorize the actuation of the LF key, and the program proceeds to a step S60.
On the other hand, in case the actuation of the FF switch in the off-line state is detected in a step S61, steps S62 to S72 are executed to advance the cut sheet either to the end thereof or until the absence of sheet is detected, or detect sheet jamming and memorize the sheet jamming, in the identical manner as the case when the FF signal is detected in the step S23. Thereafer a step S73 stores "2" in the SKEY memory to memorize the actuation of the FF key, then a step S74 sets "0" in the CSF memory and the program proceeds to a step S60.
On the other hand, in case a step S75 identifies the actuation of the PS switch, a step S76 forcedly rotates the platen motor 162 by an amount corresponding to 16 lines, then a step S77 stores "3" in the SKEY memory to memorize the actuation of the PS switch, then a step S74 sets "0" in the CSF memory and the program proceeds to the step S60.
The step S60 and ensuing steps execute the actual sheet setting, in which the steps S60 and S91 effect processes same as those in the steps S6 to S9, S14 to S17 and S42 to S48. The steps S84 to S87 activate the platen motor 162 and the motor 105 to effect one cycle of sheet feeding and discharge. In the off-line state the sheet feed and discharge are always conducted at this point.
In order to effect the sheet feed and discharge in the steps S84 to S87, there are required conditions that the cut sheet feeder is mounted and the automatic sheet feed mode is adopted, and that the contents of the CSF memory and the P-jam memory are both zero. The conditions CSF memory=0 and P-jam memory=0 are satisfied in the step S60 in one of following four cases:
I. in case the P-jam memory is set to "0" by initialization after the start of power supply, and the CSF memory is set to "0" by the FF switch or PS switch in the step S74;
II. in the on-line state, when the P-jam memory is set to "0" in the step S92 in FIG. 16B after a sheet jamming followed by the removal of the jammed sheet, and the CSF memory is set to "0" in the step S74 by the FF switch or the PS switch;
III. in the off-line state, when the P-jam memory is set to "0" in the step S93 in FIG. 19A after a sheet jamming followed by the removal of the jammed sheet, and the CSF memory is set to "0" in the step S74 by the FF switch or the PS switch; and
IV. when the on-line state is forcedly switched to the off-line state by the on-line switch, in which case the step S78 identifies the presence of sheet whereby the program proceeds to the step S90 to dispense with the sheet feed and discharge.
In the above-mentioned case I, II or II, steps S84 to S87 are executed to effect a cycle of sheet feed and discharge, and a step S88 detects the output of the sheet end sensor 157 to identify whether the sheet has been correctly set. If the sheet is absent, a step S89 sets "1" in the RC memory to indicate the absence of sheet, and the program returns to the step S49 through a step S94. Since the CSF memory is set to "1" in the step S82 in this case, the program remains in this state until either of the LF, FF and PS switches is actuated.
On the other hand, a correct sheet setting is identified by the presence of sheet in the step S88, a step S91 sets "1" in the CSF memory and the program proceeds to a step S95. Since the FF or PS switch has been actuated in this case, the program proceeds to a step S96 to identify the actuated switch. If the PS switch has been actuated, there are executed a step S98 to turn off the alarm lamp 170, a step S99 to release the on-line signal and a step S100 to turn on the on-line lamp, and the program returns to the step S4 to initiate the on-line process.
On the other hand, in case the step S96 identifies the actuation of the FF switch, the program proceeds to a step S97 to identify whether the cut sheet feeder is mounted, and, if yes, to the step S98, or, if not, to a step 101 to identify whether the on-line switch has been actuated.
As explained above, in case the PS switch has been actuated and the presence of sheet is detected, the program enters the on-line state, regardless whether the cut sheet feeder is mounted or not. Also in case the FF switch has been actuated and the presence of sheet is detected, the program moves to the on-line state or remains in the off-line state respectively when the cut sheet feeder is mounted or not.
Also in the aforementioned case IV, the actuation of the FF or PS switch causes the discharge of a presently loaded sheet and the feeding of a new cut sheet, but such sheet discharge and feeding do not take place in response to the actuation of the LF switch. However, in case the sheet end is detected in the step S78, a cycle of sheet feed and discharge is automatically conducted because of the conditions CSF memory=0 and P-jam memory=0. Also a cycle of sheet feed and discharge is automatically effected in case the absence of sheet is detected in the step S78. Consequently, in case the operator manually rotates the platen to discharge the cut sheet loaded thereon, a cycle of sheet feed and discharge is automatically effected.
Manual feed mode
In the manual feed mode, all the operations are conducted in the printer alone, and the cut sheet feeder is disabled.
In the foregoing, the function of the present embodiment has been detailedly explained. However, for the purpose of helping further understanding, FIGS. 20A to 20H and 21 show the relationship among the functions of the platen motor 162 and feeder motor 105, and the position of a cut sheet. When a new cut sheet 135 is fed to the printer (FIG. 20A), the feeder motor 105 is at first rotated in the reverse direction and then in the forward direction, whereby the cut sheet is supplied to the platen 52. The leading end of the cut sheet passes the position of the sheet end sensor 157 (FIG. 20B), and then reduces a position between the platen 52 and the pinch roller 56 (FIG. 20C). Subsequently the platen 52 is further rotated by a small amount to form a loop in the leading end portion of the cut sheet (FIG. 20D). Then the feeder is stopped and the platen motor 162 is rotated by a determined amount to feed the cut sheet to the print start position (FIG. 20E). subsequently the printing operation is initiated, with the advancement of the cut sheet by the rotation of the platen 52, and the end of the cut sheet 135 is detected by the sheet end sensor 157 (FIG. 20F). From this position the platen 52 is further rotated until the end of the cut sheet 135 is released from the platen 52 and the pinch roller 54 (FIG. 20G). Then the platen 52 is stopped and the sheet discharge roller 120 is activated, thus discharging the cut sheet completely to the discharged sheet tray (FIG. 20H).
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There is disclosed a simplified sheet feeding system for a recording apparatus such as copier. A sheet is pinched between ribs projecting on a sheet guiding face and driven feed rollers which are movable in position and partly overlap with the projecting ribs when the sheet is absent.
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BACKGROUND OF THE INVENTION
The present invention relates to a video format conversion system, and in particular to a video format conversion system for converting interlaced video into progressive video.
Video displays generally have a plurality of scan lines that are displayed at regular intervals. Traditional displays, such as those used in regular television displays, have used interlaced scan displays. Interlaced systems divide the scan lines of each frame of video into two fields, each of which consists of one half (every other line) of the total number of scan lines in the frame. The resolution of interlaced scan displays is limited because each field is separately displayed with the lines of the alternate field being black. As an example of an interlaced system, in an NTSC system each interlaced field is displayed every {fraction (1/60)}th of a second and a complete frame is displayed every {fraction (1/30)}th of a second (two fields).
Higher quality displays, such as high definition television, use a progressive scan display system. In a simple progressive scan display system, the number of scan lines visible at a given instant is twice that which is visible in a corresponding interlaced system. Progressive video means that every line of the image signal is successively displayed instead of every other line as contemplated by the term interlaced video. In other words, the term progressive video means not interlaced video.
The conversion from interlaced video to progressive video may be accomplished by scanning the interlaced video at twice the horizontal rate to double the number of scan lines of video information. Each line of interlaced video of a field is displayed and the missing lines (that would normally be black) between the lines of the interlaced video are interpolated.
Many systems for interpolating video pixel information of interlaced video to progressive video are known. Such systems can be broadly categorized into one of three types.
The first type of interpolation system is intra-field interpolation which involves interpolating the pixels of lines not scanned by using the pixels of scanned lines only in the current field. Normally such systems result in a deterioration of image quality because each line is interpolated in some manner by the mean value of pixels on directly adjacent upper and lower lines with respect to the line being interpolated. The simplest intra-field system averages the value of the pixel immediately above and the value of the pixel immediately below the interpolated pixel to obtain an average pixel value. While filling the black regions between interlaced lines of video, this particular intra-field method neither provides for sufficient image quality nor eliminates flicker associated with small details.
The second type of interpolation system is inter-field interpolation which involves interpolating lines not scanned during the current field by using scanned lines of the current field together with scanned lines of past and/or future fields, without any motion compensation. Although this method may result in high image quality for video with stationary scenes, severe artifacts arise for video portions that involve motion. An alternative inter-field interpolation method stores one field and uses it to fill the spaces in the following field. This approach is satisfactory except for video portions that involve motion because a moving object will be at different locations in adjacent fields. In other words, such an interpolated frame, consisting of two superimposed fields, will present a moving object at one location on even lines and at another location on odd lines, thus producing a double image of the object.
The third type of interpolation system is interpolation with motion compensation which attempts to solve the problems encountered with the presence of motion associated with the intra-field interpolation method and the inter-field interpolation method without motion compensation. However, motion compensation normally requires substantially more computation, at increased time and expense. Many interpolation systems try to compensate for the presence of motion by sampling pixel values in an area around the desired pixel and extending the sampling of pixels to past and future fields in the region of the desired interpolated pixel. Difficulties of motion compensation for interlaced video include compensating for the sampling of pixels that are not in the same spatial location in the immediately prior and immediately subsequent fields of the field including the interpolated pixel. Also, in the event of a scene change, i.e., an event involving a substantial amount of video change, such systems tend to fail.
Lee et al., U.S. Pat. No. 5,428,397, disclose a video format conversion system for converting interlaced video into progressive video using motion-compensation. The Lee et al. system uses both an intra-field technique and an inter-field technique to achieve the conversion. The system determines if the current pixel is stationary, and if so then an inter-field technique is used to determine the value of the interpolated pixel. In contrast, if the system determines that the current pixel is in motion, then an intra-field motion compensating technique is used to determine the value of the interpolated pixel. In particular, the intra-field technique taught by Lee et al. uses a simple luminance mean calculating circuit connected to a pair of line delay circuits. Accordingly, the relatively fast inter-field technique is used on the non-motion portions and the relatively slow intra-field technique is used on the motion portions for which the relatively fast inter-field technique is not suitable.
Bretl, U.S. Pat. No. 5,475,438, discloses a pixel interpolation system for developing progressive line scan video from two interlaced fields of video, using both an intra-field technique and an inter-field technique. An intra-field pixel value is determined by averaging the pixel luminance in the line above and the pixel luminance in the line below the desired pixel. A motion value is determined indicative of motion of the image. An inter-field pixel value is determined by comparing the intra-field pixel value with the corresponding pixels in the previous and subsequent frames. The motion value is used to proportion the intra-field and the inter-field pixel values to compute a value for the desired pixel. The system taught by Bretl is computationally complex, thus requiring expensive electronics and excessive time to compute.
Simonetti et al., in a paper entitled A DEINTERLACER FOR IQTV RECEIVERS AND MULTIMEDIA APPLICATIONS, disclose a system for converting interlaced video to progressive scan video. Simonetti et al. suggest that their objective is to improve picture quality with a fast, low-cost device by using simple but effective algorithms with an optimized design flow and silicon technology suitable for ASIC developments. The system includes motion detection by computing the absolute luminance differences between selected pixels, and thereafter selecting either an intra-field or inter-field interpolation technique. When motion is detected, an intra-field technique is used to attempt to avoid smearing the borders of objects in the proximity of the pixel. Simonetti at al. attempt to keep the blurring low by performing an interpolation along a direction of high correlation of the luminance data in the vicinity of the pixel. The algorithm taught by Simonetti et al. includes performing an extensive number of comparisons (conditional executions) for each pixel and then selecting the proper action based upon one or more of the comparisons. Unfortunately, in conventional RISC processors conditional executions, which are used to perform such comparison operations, require substantial time to execute. Accordingly, to maximize computational speed when using a RISC processor, the number of conditional executions should be minimized.
Hong, U.S. Pat. No. 5,493,338, discloses a system for converting interlaced video to progressive video by utilizing a three dimensional median filter. The three dimensional median filter applies a weighing factor to pixel luminance components of horizontal, vertical, and diagonal directions of the pixel component's periphery to be interpolated by horizontal, vertical, and time axis judging signals. However, Hong does not use edges in the video when determining pixel interpolation which may result in decreased image quality.
Marsi et al., in a paper entitled VLSI IMPLEMENTATION OF A NONLINEAR IMAGE INTERPOLATION FILTER, disclose the conversion of interlaced video to progressive video by interpolating along either the vertical or the horizontal direction using an operator function. The operator function is designed to preserve edges within an image. However, such an operator function does not account for image movement or provide adequate results for non-horizontally or non-vertically oriented edges.
Dong-I 1 , U.S. Pat. No. 5,307,164, discloses a system for conversion of interlaced video to progressive video by linearly interpolating through a slant correlation of a low-pass interpolation signal and through “0” insertion of a high-pass interpolation signal in a vertical direction. The slant correlation technique involves obtaining the mean luminance value of highly correlated pixels, wherein the correlation of the pixels is detected in diagonal directions and vertical directions by a series of calculations. Thereafter, the greatest correlation (smallest mean value) is determined by a series of comparisons and used to select which two pixels to average in order to calculate the interpolated pixel.
Patti et al., U.S. Pat. No. 5,602,654, disclose a two-step, contour sensitive deinterlacing system especially suitable for obtaining still images from interlaced video. The first step determines for each missing pixel of an interlaced field whether the absolute difference between the luminance of the pixels above and below the missing pixel is greater than a preselected threshold value. If it is decided that the missing pixel lies at a low-vertical frequency location, its value is estimated via vertical interpolation. Otherwise, the second step determines whether or not there is a well-defined contour passing through the missing pixel, and determines the contour's direction if there is one by comparing blocks of pixels. In the presence of a well defined contour, the missing pixel is obtained by averaging the intensity values along the direction of the contour in the field lines immediately above and below the missing field line. However, the computational requirements necessary to process the blocks of data, as taught by Patti et al., to determine the contours are excessive.
Martinez et al., in a paper entitled SPATIAL INTERPOLATION OF INTERLACED TELEVISION PICTURES, teach a system for converting interlaced video to progressive video by an algorithm that attempts to determine edges of features within an image by using corresponding sets of pixels of two adjacent lines of interlaced video. The algorithm is based on a line shift model, in which small segments of adjacent raster scan lines are assumed to be related by a spatially varying horizontal shift. The algorithm taught by Martinez et al. involves two steps. The first step is to estimate of the velocity obtained from a window of image samples surrounding the point of interest. For color pictures, this operation is carried out only on the luminance component. In order to compute the velocity estimate Martinez et al. teach that a set of linear equations must be solved for each point, which is computationally intensive and potentially requires expensive electronics. The second step involves projecting the velocity estimate onto the two lines adjacent to the desired interpolated pixel and the image intensities at the corresponding points are averaged together. For color pictures, this operation takes place on each component color.
Conceptually the algorithm taught by Martinez et al. can be thought of as fitting a surface to a series of points on two adjacent interlaced lines of video. Then at the point of interest the gradient is determined, which is the direction of the steepest slope on the surface to that point of interest. The perpendicular to that gradient is the flattest portion at that point on the surface and is considered an edge to a feature. The interpolation is performed with pixels generally along that perpendicular to maintain the contour of the edge. Accordingly, Martinez et al. teach that pixel values from both lines are used to compute the interpolated line of pixels. Further, when proceeding to the next set of two lines of interlaced video, one line of which was used for the interpolation of the preceding interpolated line, there is no reusable data to simplify the calculations because of the “surface” nature of the calculations.
What is desired, therefore, is a system for converting interlaced video to progressive video that is not computationally intensive and results in retaining edge information for features within the video.
SUMMARY OF THE INVENTION
The present invention overcomes the aforementioned drawbacks of the prior art by providing a system for processing an image containing at least a first line and a second line, where each of the first and second lines includes a plurality of pixels, to generate an interpolated line where the interpolated line includes a plurality of interpolated pixels located intermediate the first and second lines. The system selects a first set of pixels from the first line and a second set of pixels from the second line and generates a first set of filtered values by filtering the first set of pixels with a first filter and a second set of filtered values by filtering the second set of pixels with a second filter. The system identifies in the first line at least one edge location in the first set of the filtered values by a first filtered value of the first set of filtered values being at least one of less than and equal to a first predetermined value and a second filtered value of the first set of the filtered values being at least one of greater than and equal to the first predetermined value. The system also identifies in the second line at least one edge location in the second set of filtered values by a first filtered value of the second set of the filtered values being at least one of less than and equal to a second predetermined value and a second filtered value of the second set of filtered values being at least one of greater than and equal to the second predetermined value. The system then interpolates based on the at least one edge location of the first line and the at least one edge location of the second line to generate at least one of the interpolated pixels of the interpolated line.
In an alternative embodiment the system includes a third line which includes a plurality of pixels and the interpolated pixels are located intermediate the first and third lines. The system selects a third set of pixels from the third line and generates a third set of filtered values by filtering the third set of filtered values with a third filter. The system selects at least one of a plurality of putative edge features based upon a first selection criteria where each putative edge feature is defined by a set of filtered values including at least one filtered value of the first set of filtered values, at least one filtered value of the second set of filtered values, and at least one filtered value of the third set of filtered values. The first selection criteria is defined by at least two of the at least one filtered value of the first set of filtered values, the at least one filtered value of the second set of filtered values, and the at least one filtered value of the third set of filtered values being at least one of greater than and equal to a predetermined value and at least one of less than and equal to the predetermined value. The system interpolates based on selecting at least one of a plurality of putative edge features to generate at least one of the interpolated pixels of the interpolated line.
In the preferred embodiment a fourth line of pixels is used and the putative edge feature includes the fourth line of pixels. The system then includes a second selection criteria defined by at least two filtered values of, a filtered value of the first set of filtered values, a filtered value of the second set of filtered values, and a filtered value of the third set of filtered values being the non-selected one of the at least one of the greater than and equal to the predetermined value and the at least one of the less than and equal to the predetermined value of the putative selection selected as a result of the first selection criteria. The system then interpolates based on selecting at least one of a plurality of putative edge features including the first selection criteria and not the second selection criteria to generate at least one of the interpolated pixels of the interpolated line.
In both embodiments the system converts interlaced video to progressive video using a technique that is not computationally intensive and results in retaining edge information for features within the video. Also, the technique maintains edge details of an image when encountering luminance changes, such as shadows obscuring an edge feature. The principal technique used to maintain such edge features is by not directly using the pixel luminance values themselves but instead using “binary” edge features which provides higher resultant image quality. Another advantage of the system is that each set of calculations performed on a single line of interlaced video may be used for both the interpolated pixels above and below the line of interlaced video, without recalculation of the pixels values using the filter.
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 DRAWINGS
FIG. 1 is a block diagram of an exemplary system that includes an intra-field interpolator, an inter-field interpolator, and a motion detector.
FIG. 2 is a representation of interlaced video and progressive video.
FIG. 3 is a representation of pixels, a portion of two lines of interlaced video.
FIG. 4 is a set of sample pixel luminance values.
FIG. 5 is a set of filtered values obtained by filtering the pixels of FIG. 4 with a [−1+2 −1] filter.
FIG. 6 is a set of polarity values of the filtered values of FIG. 5 used to identify edge features.
FIG. 7 is a set of thresholded values containing primarily zeros with scattered positive (+) and negative (−) values obtained by passing a set of filtered values through a threshold filter.
FIGS. 8-12 show a set of exemplary selection criteria for the thresholded values of FIG. 7 .
FIG. 13 shows a set of vertical edge conditions for the selection criteria of FIG. 12 .
FIG. 14 shows an alternative set of vertical edge conditions for the selection criteria of FIG. 12 .
FIG. 15 shows a set of vertical edge conditions for one of the selection criteria of FIG. 8 .
FIG. 16 shows an edge selection test.
FIG. 17 shows an edge putative selection for FIG. 16 .
FIG. 18 shows an exemplary embodiment of the steps of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1, a combination intra-frame and inter-frame motion adaptive interpolation system 8 includes an input luminance signal Y in . Y in is used for interpolating a line within the field to be interpolated by an intra-field interpolator 10 and an inter-field interpolator 12 . Based upon the judgment of a motion detector 14 that judges motion within the input image, a pixel to be interpolated within a region corresponding to the motion is interpolated either with the intra-frame interpolator 10 or with the inter-field interpolator 12 . It is to be understood, that the system of the present invention may include any suitable system for inter-field determinations and motion detection. Also, the system may include only an intra-field interpolator, if desired.
Referring to FIG. 2, as previously described interlaced video has an image spread over two different fields of a frame. In order to convert interlaced video 20 to progressive video 30 for displays such as high definition television, the interpolated pixels between the scan lines of the interlaced video 20 need to be determined. A technique that is chosen to determine the interpolated pixels should provide a high quality image free from artifacts.
Referring to FIG. 3, an interpolated pixel X may be calculated from a given set of sequential pixels A-G of a portion of a line of interlaced video and sequential pixels H-N of a portion of a subsequent line of interlaced video. Preferably, pixels H-N are from the next line of interlaced video. It is to be understood that the system can use any suitable number of pixels above and below the interpolated pixel X. Preferably, the pixels are both sequential in order and symmetrical around the interpolated pixel X.
Many current interpolation techniques encounter difficulty maintaining edge details of an image when encountering luminance changes, such as shadows obscuring an edge feature. The inventor came to the realization that many current interpolating techniques directly use the pixel luminance values of different interlaced lines of video to identify edge features within the image. In contrast to the identification of edge features by directly using the pixel luminance values themselves, the inventor determined that the correlation of “binary” edge features provides higher resultant image quality.
The inventor observed that fitting a “surface,” as taught by Martinez et al., requires the simultaneous computation using pixel intensity values from a portion of both surrounding lines for each interpolated pixel of an interpolated line. When computing the interpolated pixels for the next interpolated line, the pixel intensity values of the shared line of interlaced video (the line between the two interpolated lines) are reused to recompute the next “surface.” In contrast to the teachings of Martinez et al., the inventor came to the realization that using an interpolating technique that computes a function, or otherwise uses a filter, for each portion of an interlaced line of video, where the function of each line is independent of the other lines of interlaced video, permits a subsequent calculation for the next interpolated line to reuse the prior calculation performed on the shared line of interlaced video. In other words, each set of calculations performed on a single line of interlaced video may be used for both the interpolated pixels above and below the line of interlaced video. Using this insight, the inventor postulated that typical contours representative of an edge feature along a line of an image may be determined from either a second order filter or a high pass filter. Alternatively, any other suitable filter, such as for example, Guassian or Sobel, may be used. Such edge features may include intensity changes from low luminance to high luminance, or intensity changes from high luminance to low luminance.
Referring to FIG. 4, a set of sample pixel luminance values are shown. An exemplary second-order zero-crossing filter to be applied to the luminance values may be [−1 +2 −1]. The [−1 +2 −1] filter calculates the second derivative of three adjacent pixels of the data. The zero order crossing filter is applied to each pixel of an interlaced line of pixels by calculating the summation of the preceding luminance pixel value multiplied by −1, the current pixel value multiplied by +2, and the subsequent pixel value multiplied by −1. The set of filtered values resulting after filtering the pixels of FIG. 4 with the [−1 +2 −1] filter is shown in FIG. 5 . The resulting magnitudes of the filtered values from the zero-crossing filter applied to a line of interlaced video are not important in determining the existence of edge features, but rather the polarity values (positive or negative) of the filtered values from the zero-crossing filter, as shown in FIG. 6, are used to identify edge features. Changes from positive (+) to negative (−), or from negative (−) to positive (+) of adjacent pixels identifies an edge feature at that location. In addition, a change from positive (+) to negative (−) to positive (+), or from negative (−) to positive (+) to negative (−) of adjacent pixels may either be indicative of an edge feature or noise. A change from negative (−) or positive (+) to zero (0) may indicate an edge feature if desired.
It is to be understood that the zero-crossing filter may use non-adjacent pixels, if desired. The number of pixels used to calculate each positive, zero, or negative filtered value of from a set of luminance values may be selected, as desired. In addition, the particular filter selected may result in a set of filtered values that are not centered around zero for the identification of edge features. In such a case the identification of edge features may be based on a change from “less than” or “equal to” a predetermined value to “greater than” or “equal to” the predetermined value. Alternatively, the change may be from greater than or equal to the predetermined value to less than or equal to the predetermined value. Filtered values that match the predetermined value (zero or non-zero) may be used as indicative of edge features, if desired. Alternatively, filtered values that match the predetermined value may be disregarded and the filtered values to either side of the predetermined value(s) may be used.
The inventor realized that if a principal purpose of the interpolation system is to detect and maintain edges within the image, then the general characteristic change within each set of filtered values of two or more interlaced lines indicative of an edge feature should correlate if an edge passes through them. Accordingly, the inventor came to the realization that the edge features of two or more lines of interlaced video should be related to each other. The edge features can be tracked across the gap between the interlaced lines by identifying the edge feature closest to the column in the line above the line in which pixel X is located. Referring again to FIG. 6, for the upper line (the line above the interpolated pixel X) the closest edge feature is column 3 to column 4 as the sign changes from positive (+) to negative (−). The change from negative (−) to zero (0) of column 4 to column 5 may be indicative of an edge feature, albeit likely a smaller edge feature than a polarity change. In addition, the negative (−) to zero (0) to positive (+) of columns 4-6 may be ignored, if desired.
Next, the lower line (the line below the interpolated pixel X) is searched for an edge feature on the opposite side of the interpolated pixel X from the edge feature identified in the other line, which is indicated by the positive (+) to negative (−) edge feature of columns 4 to column 5 (FIG. 6 ). If multiple edge features (transitions) are located in the neighborhood of X in the lower line, then the transition location for which the lower line pixel luminance most closely matches the pixel luminance of the edge feature in the upper line is selected as the matching point. There is a limited region of columns about the interpolated pixel X over which edge features are searched for, such as, for example, three columns to either side of the interpolated pixel X. After identifying the edge transitions about the interpolated pixel X, a linear interpolation is performed along the direction defined by the edge. Referring again to FIG. 6, the linear interpolation of the interpolated pixel X is the pixel luminance of pixel 50 and pixel 52 , namely, (9+10)/2. Alternatively, any other suitable interpolation technique may be used based on the edge features.
It is to be understood that the calculations performed on the upper and the lower lines may be reversed, if desired. Further, the lines of interlaced video used to interpolate pixel X do not necessarily need to be the lines immediately above and below the interpolated pixel X.
As previously described, the aforementioned technique is described in terms of either a positive, a negative, or a zero value. Alternatively, depending on the zero-crossing filter selected, which may include an offset factor, the comparisons for identifying edge features may be values other than positive and negative.
In the event that no edge correlation is determined, a vertical interpolation technique is used.
An alternative interpolating technique uses a high pass filter on the luminance values, such as [+1+3 −3 −1]. The [+1 +3 −3 −1] high pass filter identifies the high frequency content of a set of pixels which is indicative of an edge feature. The high pass filter is applied to each pixel of an interlaced line of pixels by calculating the summation of the second preceding luminance pixel value multiplied by +1, the preceding pixel value multiplied by +3, the current pixel value multiplied by −3, and the next pixel value multiplied by −1. Alternatively, the high pass filter may be shifted to the right so the preceding pixel value is multiplied by +1, the current pixel is multiplied by +3, the next pixel is multiplied by +1, and the next pixel value is multiplied by +3. The filtered values from the high pass filter of a line of interlaced video is then applied to a threshold function to assign filtered values the value of zero that have an absolute value less than a predetermined threshold. This sets lower frequency components to the same value, preferably zero, as less indicative of edge features. The remaining non-zero values indicate the existence of high frequency features within the image, such as an edge feature. The magnitudes of the resulting non-zero filtered values from the high frequency filter applied to a line of interlaced video are not important in determining the existence of edge features but rather the polarity values (positive or negative) from the thresholded high pass filter are used to identify edge features. Changes from positive (+) to negative (−), or from negative (−) to positive (+) of adjacent pixels identifies an edge feature at that location. In addition, a change from positive (+) to negative (−) to positive (+) of adjacent pixels or from negative (−) to positive (+) to negative (−) of adjacent pixels may either be indicative of an edge feature or noise.
It is to be understood that the high pass filter may use non-adjacent pixels if desired. The number of pixels used to determine each positive, zero, or negative filtered value may be selected as desired. In addition, the particular high pass filter used may result in a set of filtered values that are not centered around zero to which a threshold filter is applied. In such a case the threshold filter would eliminate, or otherwise set to a constant, a range of filtered values indicative of low frequency features of the image. In such a case the identification of edge locations may be based on a change from “less than” or “equal to” a predetermined value to “greater than” or “equal to” the predetermined value. Alternatively, the identification of edge locations may be based on a change from greater than or equal to the predetermined value to less than or equal to the predetermined value. Preferably, the predetermined value would be the value to which the low frequency features are set, such as zero.
With the proper selection of the threshold values the resulting matrix of values contains primarily zeros with scattered positive (+) and negative (−) values, such as exemplified by FIG. 7 . The preferred technique includes the use of two lines above and two lines below the interpolated pixel X. The system compares the polarity values of the filtered pixel values on the lines above and the lines below the interpolated pixel X among a set of different general directions about the interpolated pixel X. The system may use any suitable set of filtered pixel values about the interpolated pixel X. By extending the system to include two lines above and two lines below the interpolated pixel X the system can more readily identify significant edge features. If desired, the system may use fewer or additional lines above and/or below the interpolated pixel X.
Based on the general angle being examined about pixel X, or otherwise the selected set of filtered values, the preferred putative selection criteria are the same positive or negative sign values in the line directly above and the line directly below the interpolated pixel X and at least one of the second line above and the second line below the interpolated pixel X. The multiple sets of pixels at different angles may be selected as desired, such as those shown in FIGS. 8-12. In the examples of FIGS. 8-12, selections 60 and 62 match such a criteria. Alternatively, the criteria may be any suitable number of the same sign value on any set of suitable lines in a general direction, or otherwise any selected set of filtered values, about the interpolated pixel.
For those sets of pixels that match the putative selection criteria then a second test is preferably performed. For each initial match the system checks the filtered values to ensure that an opposing edge of opposite sign does not cross the putative edge feature. The opposing edge may be checked in the vertical direction across the line at intermediate pixel locations from each end of the line (set of pixels). Referring to FIG. 13, for the putative selection 62 the seven vertical edge conditions 64 a - 64 g would be checked, as shown, to ensure that negative (alternate polarity) values are not present on both sides of the selection 62 . Alternatively, referring to FIG. 14, the system may check vertical edge conditions 66 a - 66 g of pixels above and below the selection 62 , such as shown in FIG. 14 . Referring to FIG. 15, the putative selection 60 has a greater slope than the putative selection 62 of FIG. 12 . Accordingly, several fewer checks are necessary to validate the non-crossing of an opposite polarity edge. Accordingly, for generally horizontal lines the greater number vertical opposing edge conditions to be checked increases the likelihood of removing that putative line as a candidate. This counterbalances the false tendency of such low angle horizontal lines to indicate an edge feature because the filtered values used for the edge feature are distant from one another, and may in fact be related to different edge features. The more vertically oriented lines are less likely to be removed by such an additional opposing edge condition check.
It is to be understood that the vertical conditions may check pixel values close to or more distant from the line as desired, and need not actually cross the line of the putative edge feature (e.g., the opposing check pixels are all to one side of the line). In addition, the vertical conditions may be at an oblique angle, if desired. Preferably, the vertical pixels checked only extend the length of the pixels indicating the putative edge feature.
Alternatively, for those sets of pixels that match the putative selection criteria an alternative second test may be performed. For each initial match the system checks the filtered values to ensure that an opposing edge of opposite sign does not cross the putative edge feature. The opposing edge may be checked in both an oblique angle and a vertical direction by checking groups of pixels on either side of the putative edge feature. Referring to FIG. 16, a set of three upper pixels 80 a - 80 c are checked to determine if any has a negative (alternate polarity) value and a set of three lower pixels 82 a - 82 c are checked to determine if any has a negative (alternate polarity) value. If a negative (alternative polarity) value is determined for at least one of the upper pixels 80 a - 80 c and at least one of the lower pixels 82 a - 82 c then the putative selection 62 is removed as an edge feature candidate. Also, a set of two upper pixels 84 a - 84 b and a set of two lower pixels 86 a - 96 b are checked in the same manner as pixels 80 a - 80 c and 82 a - 82 c . In addition, a set of three upper pixels 88 a - 88 c and a set of three lower pixels 90 a - 90 c are checked in the same manner as pixels 80 a - 80 c and 82 a - 82 c . Using blocks of pixels allows for the detection of opposing edges at different oblique angles with fewer comparisons than would be required if each combination of the pixels in the respective blocks were compared to each other.
It is to be understood that the pixel groups may check pixel values close to or more distant from the line, as desired, and need not actually cross the line of the putative edge feature (e.g., the opposing check pixels are all to one side of the line). Also, the pixel groups may extend only the length of the pixels indicating the putative edge feature, if desired. The pixel groups may include any suitable number of pixels and number of separate groups, as desired.
It was determined by the inventor that frequently the putative edge that satisfies either of the aforementioned second tests may still not be an actual edge feature. In many cases such erroneous edge features may be determined by mere coincidence in regions of an image that contains excessive texture. To determine if the putative edge is more likely an actual edge feature the system may further include checking for same polarity edges that cross the putative edge feature. The system preferably does not consider pixels close to the putative edge, such as within one pixel distance from the line, to permit edge features of greater width to still be considered edge features. The preferred selection of the same polarity pixels are those within a rectangle defined by the limits of the length of the line and greater than one pixel distant from the line. If any of the preferred selection of the same polarity pixels have the same polarity then the putative edge feature is not selected.
Referring to FIG. 17, for the putative selection 62 the preferred selection of the same polarity pixels would be 96 a - 96 e and 98 a - 98 e . Alternative pixels and the criteria used for matching the same polarity pixels may be selected, as desired.
In the event of no edge correlation, a vertical interpolation technique is used.
Alternatively, a match among any three or four pixels values of the four lines of interlaced video along in a general direction about the interpolated pixel X may be used. In addition, additional lines of interlaced video may be used, if desired.
The edge feature identification and selection criteria described in relation to the zero-crossing filter and the high pass filter may be switched with one another, if desired. In addition, any of the previously described techniques are likewise suitable for use with curved edges and arcs.
FIG. 18 shows an exemplary embodiment of the steps of the invention.
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.
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A system processes an image containing a first line and a second line, where the first and second lines includes a plurality of pixels, to generate an interpolated line. The system selects a first and second set of pixels from the lines and generates a first set and second set of filtered values. The system identifies in the first line an edge location in the first set of the filtered values by a first filtered value of the first set of filtered values being at least one of less than and equal to a first predetermined value and a second filtered value of the fist set of the filtered values being at least one of greater than and equal to the first predetermined value. The system also identifies in the second line an edge location in the second set of filtered values by a first filtered value of the second set of the filtered values being at least one of less than and equal to a second predetermined value and a second filtered value of the second set of filtered values being at least one of the greater than and equal to second predetermined value. The system then interpolates based on the edge location of the first line and the edge location of the second line to generate an interpolated pixel of the interpolated line.
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This application is a continuation of application Ser. No. 08/350,494, filed Dec. 6, 1994 now abandoned which is a continuation of application Ser. No. 08/030,939, filed Mar. 12, 1993 now abandoned.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to paper reprocessing, and more particularly to the repulping of wet strength broke.
2. Background
Broke is waste or off-spec paper which is to be recycled. It is generally more desirable to recycle the broke by a process called repulping, than it is to merely dispose of the broke as waste paper.
In the repulping process, the cellulose fibers which make up the broke are sufficiently separated from the broke to make them usable for manufacturing paper. Repulping wet strength broke is difficult because such broke contains a wet strength resin (such as a polyamide-epichlorhydrin resin) added during paper production to enhance the strength of the paper produced so that the paper does not fall apart when used under wet conditions. The wet strength resin binds the cellulose fibers together, forming a water impervious coating, which impedes the repulping process goal of separating the cellulose fibers. Paper towels, tissues, food wrappings, and other paper products are typically treated with wet strength resins to prevent their deterioration when used under wet conditions. Typically, paper treated with wet strength resins will retain at least 15% of the paper's dry strength when wet. Paper without wet strength resin generally retains only 2-7% of its dry strength when wet.
Oxidation facilitates the break down of the wet strength resin to permit separation of the cellulose fibers. Traditionally, hypochlorite, particularly sodium hypochlorite, has been used by paper mills in the repulping of wet strength broke to oxidize the wet strength resin to facilitate fiber separation. When so used, hypochlorite oxidizes the wet strength resins within a narrow, carefully maintained pH range and within a temperature range of from about 122° F. (50° C.) to 150.8° F. (66° C.). After broke has been successfully repulped, an antichlor is added to neutralize the remaining chlorine.
Environmental issues have been raised concerning the use of hypochlorite for repulping. These concerns relate to the formation of organic halides which are adsorbed by the pulp, chloroform emission, and the problem of adding toxic chlorinated hydrocarbons to the effluent stream. For these reasons, non-halogen containing compounds, such as persulfates have been used to oxidize wet strength resin during the repulping process.
SUMMARY OF THE INVENTION
We have discovered that persulfate salts used in conjunction with a carbonate, bicarbonate or sesquicarbonate enhances wet strength broke repulping performance by facilitating the separation of cellulose fibers from the broke. In addition, we have discovered that relatively uniform dry mixtures of persulfate and carbonate, bicarbonate or sesquicarbonate can be prepared which do not separate in storage containers, and which exhibit substantially increased handling safety over persulfate alone. Moreover, we have discovered that the ratio of persulfate to base can be adjusted to provide a neutral, acid, or basic pH during the repulping process for the oxidation of the wet strength resin. Such pH regulation by adjustment of the persulfate to base ratio in the combined product avoids the need for an additional process step for pH adjustment and permits a single package chemical treatment for repulping.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The use of the term "about" herein shall be inferred when discussing ranges, dosages, weight percent or other numerical designation, unless otherwise specified.
The term "persulfate" includes any persulfate salt including sodium persulfate, potassium persulfate, and ammonium persulfate, unless otherwise specified.
The terms "carbonate", "sesquicarbonate" and "bicarbonate" include the alkali, the alkaline earth and the ammonium salts of carbonate, sesquicarbonate or bicarbonate.
The term "base" as used herein means a carbonate, a sesquicarbonate, or a bicarbonate.
The term "dry" indicates a composition or substance which does not feel moist to the touch. A dry composition can have water of hydration.
All percents are weight percent unless otherwise expressly specified.
The term "owf" is a dosage term which means based on the dry weight of fiber.
Composition
The compositions of this invention are designed for repulping wet strength broke and include a persulfate and a base such as carbonate, bicarbonate, or sesquicarbonate. An effective ratio of persulfate to the base should be used. A persulfate to base ratio of from 10:90 to 90:10 is effective, although a composition having a ratio outside this range can be effective depending on use conditions such as pH, the type or quantity of oxidizable material, and temperature. A persulfate to base ratio of from 60:40 to 90:10 is more preferred, and a persulfate to base ratio of from 70:30 to 80:20 is most preferred.
The persulfate to base ratio is based on the weight of the sodium salts of the persulfate and the base unless otherwise specified.
Examples of specific compounds included as bases include the following: sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, calcium carbonate, sodium sesquicarbonate, potassium sesquicarbonate, and the like.
The Process
The compositions of this invention can be used to repulp broke. The repulping process is broadly described as follows: Water and broke are placed in a vessel, and agitated. Agitation consists in using a mixer/shearer such as are commonly used in the industry to mix the broke, water, and chemicals in the repulping operation, as well as to comminute the broke. The use of a mixer/shearer or a mixer plus a shearer are equivalent operations in repulping. The persulfate and base can be added prior to, or during agitation.
Different types of site addition can be used. The persulfate and the base can be mixed on site in dry form and fed as a dry mixture. The persulfate and the base can be added simultaneously to the repulping mixture as a dry powder, a slurry, a solution, or other form which one of ordinary skill in the art could put into practice without undue experimentation on the basis of the informaton provided herein. Alternatively, the base can be added first, followed by persulfate addition.
The repulped broke may be introduced directly into the paper making process as a slurry without further modification. Paper can be made from the repulped broke by separating the cellulose fibers from the slurry and introducing the fibers to a fourdrinier upon which paper is made.
Temperature
The persulfate/base combination works best if the temperature of the system is greater than 122° F. (50° C.). A temperature within the range of 122° F. (50° C.) to 167° F. (75° C.) is generally sufficient to activate and support the oxidation of the wet strength resin during repulping. Higher temperatures can be used, but are generally not required.
Time
Efficacy is improved if the resulting mixture is agitated for sufficient time to defiber the broke to produce a satisfactoy pulp. The time can vary depending on factors such as concentration of the persulfate and base, amount of oxidizable material, pH, and temperature. The use of the persulfate/base composition as a dry blend provides a significant time advantage over the use of persulfate alone or base alone. Time reductions greater than 20%, some greater than 50%, and others greater than 100% have been experienced. The time variable can be optimized by one of ordinary skill in the art on the basis of the information herein disclosed.
pH
In addition to time, pH can be controlled. Although a wide pH range is usable, the repulp time can be affected by the final system pH. A final pH compatible with plant systems is preferred. It is desirable to select a pH range which optimizes the repulping process. However, many times pH control also reflects the desirability of obtaining a final pH for the system which is compatible with other stages of paper production. For example, when a satisfactory pulp is produced, the process water is typically mixed with processed pulp from other sources, which may have acid, neutral, or base pH's. Or water from such other processes may be used as the makeup water for the broke repulping process.
Measures can be taken to avoid the addition of chemicals at each process transition for pH adjustment. This is achievable using the compositions of this invention as follows:
The ratio of persulfate to base can be selected to provide a neutral pH effect. That is, as the persulfate is consumed during the repulping process, bisulfate is produced. A neutral pH effect is achieved by adjusting the amount of base used to offset the reduction in pH attendant acid production during repulping. Normally, the bisulfate produced from the persulfate is the only acid which need be considered. However, if large amounts of other acids are produced from decomposition of the fiber or the resin, those acids may have to be considered.
Alternatively, if the pH of one process, e.g. the paper making process, differs from the pH of the wet strength broke repulping process, adjustments in pH can be made for the repulping process by varying the persulfate:base ratio to avoid any need for subsequent pH adjustment. Thus, acid, neutral or alkaline paper making processes can be accommodated without requiring an additional pH adjustment step. These adjustments can be achieved by one of ordinary skill in the art looking at the guidelines set herein. Consideration would be given to the actual pH and alkalinity of the system to be adjusted and to the acid generated and additional alkalinity provided by the addition of a formulated persulfate/base product.
Dosage
Also, an effective dosage of the composition is desired. Dosages of greater than 0.5% owf (owf means based on the dry weight of dry fiber or broke) are generally effective. The effective dosage is dependent upon system conditions, and can be determined by one of ordinary skill in the art based on the information disclosed herein. A preferred dosage is 1% to 15% owf. A more preferred dosage is 2% to 12% owf. Higher or lower dosages than the ones specified herein can be effective depending on the change in system parameters.
The parameters indicated above, are useful in repulping wet strength broke. A standardized procedure for accomplishing this is provided below.
Procedure for Repulping Wet Strength Broke
The breakdown of the resin used in wet strength broke is accomplished and measured by TAPPI method T-205-om81 for repulping wet strength broke, as described below, including any variances.
1500 ml of 70° C. (158° F.) water is poured into a 2 liter pyrex beaker. The pH is adjusted and the desired repulping composition added. The 3.0 resulting slurry is then poured into a preheated disintegrator vessel which is adjusted to a maintenance temperature of 65° C. (149° F.). 20 grams of pre-cut 1 inch broke squares are then added, and the disintegrator is started with continuous sample mixing at 2800 rpm. Temperature readings and 10 ml aliquots are taken every 5 minutes. These 10 ml aliquots are diluted to 200 ml with tap water, and then compared with standard samples for stages 1 through 6 (described below). Sampling continues until a stage 6 sample is obtained. If no stage 6 sample is obtained, sampling ceases at the end of 60 minutes. The pH, temperature and residual oxidizer measurements of the final sample are recorded.
During the above described TAPPI repulping method the pulp characteristics change from clumps of cut up resin coated paper (stage 1 ) to a relatively uniform mixture of free cellulose fiber (stage 6). These standards are described below.
Standard Samples for Stage 1-6
Repulp stages are determined by direct comparison to pre-made standards made according to the above TAPPI repulping method. These standards are characterized and designated as "stages", starting with stage 1 and ending with stage 6. The stages are defined as follows:
Stage 1 is characterized primarily as a broke having numerous large fiber flakes.
Stage 2 is characterized as a broke having having large flakes, and small flakes.
Stage 3 is characterized as a broke having primarily numerous small fiber flakes.
Stage 4 is characterized as a broke having primarily few small flakes, and numerous bonded fibers.
Stage 5 is characterized as a broke which primarily has finely separated fibers and a few bonded fibers.
Stage 6 is characterized as a broke which has been repulped to finely separated fibers.
A fuller understanding of the above described stages is provided by the following review of the process.
The initial broke is a cut up paper composed primarily of numerous large fiber flakes, which is characterizable as being Stage 1. Or the initial broke is a roll of waste paper, which is comminuted by a blade, such as a high shear impeller to a paper composed primarily of numerous large flakes. As the broke is repulped, it typically becomes increasingly smaller. Ideally, repulping produces a Stage 6 pulp composed of completly separated fiber. In practice, however, a Stage 5 product consisting primarily of separated fibers and a few bonded fibers can be acceptable.
The paper that is produced from repulped broke will be finer, the more complete the fiber separation in the pulp. Generally, the less completely separated the fiber, the greater degree of clumpiness and surface irregularity in the finished paper good.
The following examples further illustrate the invention without limiting the scope thereof.
EXAMPLE 1
pH of 1% Solutions of Formulated Broke Treatment
The pH of a 1% solution of a formulated product made according to this invention was determined as described in Table 1 below.
In the test procedure, one gram Samples of formulated product were added to 99 grams of the water being evaluated. After 5 minutes mixing, the pH of the system was measured. The results are provided below and summarized in Table1.
TABLE I______________________________________EX (1)pH.sub.i (2)pH.sub.f (3)pH.sub.i (4)pH.sub.f______________________________________75% Sodium Persulfate/25% Sodium Sesquicarbonate1 5.07 10.22 7.49 10.032 4.50 10.26 7.23 10.0275% Sodium Persulfate/25% Sodium Carbonate1 5.27 11.46 6.99 11.082 4.50 10.26 7.01 11.10______________________________________ (1)pH of deionized water prior to addition of persulfate formulations. (2)pH of deionized water five minutes addition to formulations. (3)pH of tap water prior to addition of persulfate formulations. Alkalinity of tap water = 80 ppm; total hardness = 110 ppm. (4)pH of tap water five minutes after addition of formulations.
Table 1 above demonstrates that pH increases when a persulfate formulated according to this invention at 75% persulfate and 25% base is added to an aqueous solution.
EXAMPLE 2
Effect of Formulated Sodium Persulfate on pH Before and After Repulping Wet Strength Broke
Repulping experiments were conducted in tap water. In these experiments the repulping formulation was added to a repulping mixture prepared according to the TAPPI method described above. The repulping formulations were dry blends of 75% sodium persulfate and 25% of either sodium sesquicarbonate or sodium carbonate as indicated in Table 2 below.
TABLE 2______________________________________Formulation SP/Sodium Sesqui SP/Sodium Carbonate(% OWF)(1) (2)pH.sub.i (3)pH.sub.a (4)pH.sub.f (2)pH.sub.i (3)pH.sub.a (4)pH.sub.f______________________________________0.50 7.4 7.9 7.7 7.4 8.5 8.01.00 7.5 8.4 7.2 7.4 8.8 7.41.50 7.6 8.5 7.3 7.4 9.1 7.52.00 7.8 8.6 7.3 7.6 9.2 7.42.50 7.6 8.9 7.4 7.4 9.3 7.7______________________________________ (1)(% OWF)(1) = Addition of the formulated material based on the weight o the wet strength broke fiber. (2)pH.sub.i = initial pH of tap water (3)pH.sub.a = pH of the tap water after addition of treatment. (4)pH.sub.f = Final pH of the wet strength broke solution after repulping was completed.
The experiments depicted in Table 2 show that a 75% persulfate, 25% base repulping formulation is self neutralizing for the tap water used. Normally, a decrease in pH would be expected due to the formation of acid bisulfate when persulfate reacts with the resin. The self neutralization phenomenon is beneficial. It keeps the repulping mixture relatively alkaline to faciltitate incorporation into new paper production. The higher pH permits the natural alkalinity of the system to aid in the repulping by swelling the cellulose fibers and in the oxidizing of the wet strength resin.
EXAMPLE 3
Formulated -vs- Unformulated Sodium Persulfate Repulping Efficacy
The efficacy of persulfate, sesquicarbonate, carbonate and their mixtures was tested using the TAPPI repulping method described above. In each instance the initial pH of a fresh repulping mixture was measured. A formulated additive was added to the repulping mixture and the time required to attain a Stage 6 pulp was determined, as was the pH at the time of attaining Stage 6. The data is reported in Table 3.
TABLE 3______________________________________This study was conducted using tap waterFormulation Repulp Time Required ToAdditive 1 Reach Stage 6 (min.) (2)pH.sup.i (3)pH.sub.f______________________________________SP(4)/None 10-15 6.85 4.67SP(4)/Sesq(5) 5 6.80 7.62SP(4)/Carb(6) 7.5 6.84 9.06Sesq(5) 20 6.75 9.10Carb(6) 20 6.83 9.48______________________________________ (1)All additions made at 2.5% on the weight of the wet strength broke fiber (2)pH.sup.i = pH of the tap water before chemical additions (3)pH.sub.f = pH of the pulp solution after Stage 6 was achieved (4)SP = Sodium Persulfate (5)Sesq = Sodium Sesquicarbonate (6)Carb = Sodium Carbonate The SP/Carb and the SP/Sesq were each 1:1 w/w compositions.
Table 3 demonstrates that the recommended pH for repulping and optimal repulping efficacy was achieved when persulfate formulated with base was used. The data in this table also demonstrates that persulfate formulated with sesquicarbonate is more effective for repulping than is persulfate formulated with carbonate: 30% improvements have been achieved.
EXAMPLE 4
Sodium persulfate is a very reactive oxidizer, and is regulated by the United States Department of Transportation because of the ability of persulfate to start and sustain fires by oxidation. As the Examples demonstrate, sodium persulfate used with sodium carbonate or sodium sesquicarbonate is very effective for repulping resin treated broke. In order to determine whether those actives can be safely packaged together, a burn study was conducted according to the test procedure provided by the United States Department of Transportation (DOT) Code of Federal Regulations, Volume 49, Part 173, Section 175.171, "Oxidizer, Definition". The data is provided in Table 4 below.
TABLE 4______________________________________DOT Sawdust Burn Study ResultsEvaluation of Sodium Persulfate Formulationswith Sodium Carbonate or SesquicarbonateReaction Time (sec)(1)Sample ID Ratio(2) ExpA(3) ExpB(3) ExpC(3) Comments______________________________________SP(4) 1:1 128 141 136 Burned completelySP(4) 4:1 54 48 50 Burned completelySP/SC(5) 1:1 100 91 84 Self extinguished (˜25% burned)SP/SC(5) 4:1 35 42 49 Self extinguished (˜10% burned)SP/SS(6) 1:1 21 24 36 Self extinguished (˜5% burned)SP/SS(6) 4:1 14 21 19 Self extinguished (˜5% burned)______________________________________ (1)Time (sec) required for sample to burn completely or self extinguish. (2)Ratio = sawdust:sample. (3)Three experiments (replicates) were conducted; ExpA, ExpB and ExpC. (4)SP = sodium persulfate neat material. (5)SP/SC = formulation containing 75% sodium persulfate and 25% sodium carbonate 260 grade. (6)SP/SS = formulation containing 75% sodium persulfate and 25% sodium sesquicarbonate.
The data in Table 4 demonstrates that sodium persulfate formulated with either sodium carbonate or sesquicarbonate has a very high resistance to combustion, and tends to be self extinguishing if combustion does occur. Testing according to the United States Department of Transportation (DOT) Code of Federal Regulations, Volume 49, Part 173, Section 175.171, "Oxidizer, Definition" indicates that these tested formulations would be classified a non-regulated material. Sodium persulfate in non-formulated form would be classified as an Oxidizer, that is, as a regulated material according to these tests.
EXAMPLE 5
The data in Table 4 shows that sodium persulfate formulated with either sodium carbonate or sodium sesquicarbonate is safer than sodium persulfate alone. However, this safety factor would be lost if the sodium persulfate separated from the mixture.
A study was conducted to evaluate the tendency of 75% sodium persulfate and 25% sesquicarbonate or 25% carbonate to segregate. A segregation ladder having a 45 slope and 9 separate chambers was utilized. A uniform mixture of 75% sodium persulfate and 25% of either carbonate or sesquicarbonate, as indicated below, was poured evenly down the segregation ladder. Each of the nine chambers was analyzed for persulfate.
The persulfate used in the study had a bulk density of 1.25 gram per cubic centimeter. The sesquicarbonate used in the study had a bulk density of 45 pounds per cubic foot. The carbonate used in the study had a bulk density of 48 pounds per cubic foot. The test results are provided in Table 5.
TABLE 5______________________________________Segregation Study - Results______________________________________Sodium Persulfate/Sodium Carbonate Formulation← Top Bottom →of segregation ladder of segregation ladderPercent Sodium Persulfatearea1area2 area3 area4 area5 area6 area7 area8 area976.2876.30 76.94 75.93 76.74 75.82 76.68 74.38 75.26Sodium Persulfate/Sodium Sesquicarbonate Formulation← Top Bottom →of segregation ladder of segregation ladderPercent Sodium Persulfatearea1area2 area3 area4 area5 area6 area7 area8 area977.9578.81 76.85 76.82 77.20 77.82 76.96 76.47 72.28______________________________________
Table 5 above directly demonstrates the attainability of uniform mixtures of persulfate with carbonates, and sesquicarbonates and indirectly demonstrates stability where the base is bicarbonate. Such mixtures are stable and do not have a tendency to separate. This stability was unexpected in view of the structural differences between the base particles and the persulfate particles, which result in the mixtures including relatively spherical particles and needle-like particles.
EXAMPLE 6
ACID MILL WATER FORMULATION STUDY
A study was conducted to evaluate potential sodium persulfate formulations for repulping wet strength broke using acid mill water. Each formulation was also tested in water simulating neutral-alkaline paper mill water.
Optimal repulping results in neutral-alkaline paper mills have been achieved with a 75:25 SP/sodium sesquicarbonate formulation. Upon addition to the repulper, this formulation generally gives an initial pH of 9-10. Table 6 reports the results.
TABLE 6______________________________________ Addition Alkaline Water Acid WaterFormulation Level (1) pH(2) pH(3)______________________________________75:25 SP/sesqui 0.66 g 9.18 6.5275:25 SP/Na2CO3 0.66 g 9.82 7.4067:33 SP/sesqui 0.83 g 9.54 7.3267:33 SP/Na2CO3 0.83 g 10.14 9.7550:50 SP/sesqui 1.0 g 9.85 9.4650:50 SP/Na2CO3 1.0 g 10.48 10.2150:25:25 SP/sesqui/Na2CO3 1.0 g 10.24 10.0625:75 SP/sesqui 2.0 g 10.22 10.0825:75 SP/Na2CO3 2.0 g 11.06 11.02______________________________________ (1)Addition level equivalent to repulp experiment with SP at 2.5% on the weight of the fiber. (2)Initial pH of neutralalkaline water = 7.3-7.5. (3)Initial pH of acid water = 5.0-5.2
EXAMPLE 7
Two wet strength broke samples were repulped. Both were treated with a 75% persulfate/25% sodium carbonate composition. Sample 1 was a tissue paper which contained less wet strength resin than Sample 2 which was paper toweling. The results are provided in Table 7 below.
TABLE 7______________________________________ % owf minutes______________________________________Sample 1 repulped to Stage 6 as follows: 2 20 4 15 6 12.5Sample 2 repulped to Stage 6 as follows: 2 50 4 45 6 40 8 35______________________________________
This data shows that repulping time is a function of the resin levels in the broke being treated as well as the dosage levels of the persulfate/base composition. The higher the dosage level, the shorter the time required for repulping.
Eye irritation
Eye irritation studies were conducted. Those studies indicated that sodium persulfate formulated with either sodium sesquicarbonate or sodium bicarbonate on a 75/25 w/w basis were safe to use, but that if sodium carbonate was substituted as the base, substantial eye irritation could result.
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A composition containing a persulfate and a carbonate, a bicarbonate or sesquicarbonate, which composition is suitable for oxidizing wet strength resin based broke used in wet strength paper. The combination decreases the time required for effectively repulping broke from such paper. Additionally, the combination is a single product capable of beaking down the wet strength resin and adjusting or maintaining pH at a predetermined value without additional chemical treatment.
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[0001] This invention relates to a technique for drilling straight bore holes in the earth and more particularly to a stabilizer assembly and a method of making and using the same.
BACKGROUND OF THE INVENTION
[0002] As discussed at some length in U.S. Pat. No. 4,874,045, the art of drilling bore holes in the earth has evolved substantially. Initially, a bit was simply threaded onto the end of drill pipe and the resultant bore hole meandered significantly into the earth, typically in a corkscrew manner. At the present time, an attempt to drill a relatively straight vertical bore hole in the earth incorporates an elaborate bottom hole assembly including a series of stabilizers above the bit and a long length of drill collars above and interspersed between stabilizers.
[0003] It has become more desirable to drill straight vertical bore holes in the earth as wells are being drilled deeper. This is because of increased friction generated between rotating drill pipe and the bore hole. One can easily visualize that rotating drill pipe from the surface in a 20000′ well consumes considerably more horsepower than in a 5000′ well. Even where wells are drilled with a mud motor, drill pipe is also preferably rotated from the surface in order to increase the rate of penetration. Unduly meandering bore holes, and the friction generated thereby, are accordingly a much greater problem as well depths increase.
[0004] Disclosures of interest relative to this invention are found in U.S. Pat. Nos. 3,250,578; 3,938,853; 4,874,045; 5,474,143 and 5,697,460.
SUMMARY OF THE INVENTION
[0005] In this invention, a stabilizer is at least 12′ and preferably us at least about 14′ long and ideally is at least about 16′ long and includes a tube and at least three stabilizing sections integral with the tube. The stabilizer is very well balanced, meaning that rotation of the stabilizer during drilling creates very small lateral forces on the stabilizer and therefore causes very little eccentric motion, or whip, of the stabilizer during rotation.
[0006] The stabilizer is balanced mainly by making the inner and outer diameters very concentric to the tube centerline. This is accomplished by providing a cylindrical axial passage that is on the centerline of the tube, subject to very close tolerances, and a cylindrical exterior surface between the stabilizing sections that has been ground or machined to be concentric, subject to very close tolerances, to the tube centerline. Because of the small tolerances of the interior and exterior of the stabilizer, the wall thickness of the stabilizer is very consistent so the stabilizer is very well balanced, meaning there is very little whip or eccentricity during rotation.
[0007] The stabilizing sections are integral with the tube or cylindrical part of the stabilizer. This is accomplished by removing material from the blank after the axial passage has been bored. Flutes are then machined in the stabilizer sections to form ribs integral with the tube, by which is meant that the ribs are not welded or secured by fasteners to the body of the tube. The outer diameter of the ribs is somewhat less than the desired finished outer diameter to allow hardbanding followed by grinding or machining of the outer diameter to bring it to tolerance.
[0008] It is exceedingly difficult to make a long stabilizer with integral stabilizing sections to very close tolerances. It will be understood that a long stabilizer is stiffer and thus less likely to create a meandering bore hole than two short stabilizers coupled by a threaded connection. The reason, of course, is that no threaded connection is as stiff as unmachined stock of the same inner and outer diameters. All stabilizers currently manufactured for the drilling of hydrocarbon wells have maximum lengths approaching 8½′. The reason is that the grinding machines used to dress the external diameter have 8½′ centers, meaning that longer stock cannot be chucked into the machine. It is almost beyond comprehension to understand how difficult it is to find and acquire, on a basis that makes economic sense, a grinding machine or face plate lathe having 12′ or 16′ centers. Such equipment is massive, prohibitively expensive when new, and awkward to ship and install. Only an obsessive attention to detail would overcome the difficulties.
[0009] Seemingly, the main goal of this invention is to drill straight holes. This is not correct because drilling straight holes at unduly slow speeds is not acceptable to the industry because the total cost of drilling a well is directly proportional to the time it takes to drill it. Thus, the main goal of this invention is to drill straight holes at high rates of penetration.
[0010] It is an object of this invention to provide an improved method and apparatus for drilling a straight vertical bore hole in the earth.
[0011] A further object of this invention is to provide an improved stabilizer for use in a bottom hole assembly.
[0012] A more specific object of this invention is to provide a one piece stabilizer that is much longer than conventional stabilizers for use in drilling bore holes in the earth.
[0013] These and other objects and advantages of this invention will become more apparent as this description proceeds, reference being made to the accompanying drawings and appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a side view of a stabilizer of this invention coupled to a bit for drilling a bore hole in the earth;
[0015] FIG. 2 is an enlarged cross-sectional view of the stabilizer of FIG. 1 , taken substantially along line 2 - 2 thereof through a stabilizer section, as viewed in the direction indicated by the arrows; and
[0016] FIG. 3 is an enlarged cross-sectional view of the stabilizer of FIG. 1 , taken substantially along line 3 - 3 thereof through the tube, as viewed in the direction indicated by the arrows.
DETAILED DESCRIPTION
[0017] Referring to FIGS. 1-3 , there is illustrated a drilling assembly 10 comprising a bit 12 and a bottom hole or stabilizer assembly 14 . The bit 12 may be of any suitable type such as a cone-roller bearing type, a conventional diamond bit or a polycrystalline insert type. The stabilizer assembly 14 is made of one piece of metal and comprises a central tube 16 having a threaded female connection or box 18 at one end into which the bit 12 is threaded and another threaded female connection or box 20 at the other end for connection to a drill collar joint (not shown), another stabilizer (not shown) or other oil field tubular. At least three stabilizer sections 22 are located on the exterior of the tube 16 and are separated by cylindrical sections 24 . The stabilizer sections 22 are of a larger outer diameter than the tube 16 and preferably provide helical ribs 26 and flutes 28 for swirling drilling mud as it passes upwardly away from the bit 12 . A fishing neck 30 at the upper end of the stabilizer assembly 14 allows a washover pipe to pass over the top of the assembly 14 if it becomes detached or is shot off in a well.
[0018] The tube 16 provides a central passage 32 that is as concentric as reasonably possible relative to a centerline 34 . The purpose of the concentric central passage 30 is to reduce the amount of lateral motion, or whip, when the stabilizer assembly 14 is rotated during drilling. One way of measuring the concentricity of the passage 32 is by measuring the wall thickness 36 , 36 ′, 36 ″, 36 ″′ of the tube 16 in a plane at various radial locations around the centerline 34 and comparing the measurements, as suggested in FIG. 3 . In this invention, the measured wall thicknesses of the tube 16 will not vary by more than 0.050″ and, preferably, the wall thickness of the tube 16 does not vary by more than 0.025″ and, ideally, the wall thickness of the tube 16 does not vary by more than 0.010″. This is not easy to do in a stabilizer assembly that is 8½′ long and is a complicated and difficult problem in a stabilizer assembly 12′ long or longer. Centrally located passages 28 may be drilled to such tolerances by firms such as Boring Specialities of Houston, Tex.
[0019] After the metal blank is bored to provide the central passage 28 , metal is removed from the blank in the area of the cylindrical sections 24 by machining on a face plate lathe or by grinding on a grinding machine. This is accomplished by advancing the cone shaped centers of the grinding machine toward each other until they touch, or nearly touch, to determine that their centerlines are aligned. Then, the centers are retracted until they are further apart than the blank to be worked upon. The blank, having the passage therethrough that is centered as nearly as possible, is placed in the face plate lathe or grinding machine so the cone shaped centers enter the passage and thereby center the blank on the machine. The cylindrical sections 24 are then ground, or machined, to remove any eccentricity so the blank is much better balanced than is provided simply by having a bored passage nearly on the blank centerline. After these steps, the wall thickness of the blank, between the inner and outer diameters, as taken in a common plane typically varies no more than 0.005″ and is usually less than 0.002″.
[0020] Because the stabilizer assembly 14 is at least 12′ long, preferably at least 14′ long, and ideally about 16′ long, a grinding machine or face plate lathe must be large enough to receive a metal piece of this length. Grinding machines or face plate lathes of this size are not easy to find in any machine shop environment, are expensive when new and are awkward to transport and install. At the present time, there are no grinding machines or face plate lathes available in machine shops catering to the oil service industry to accomplish the desired grinding or machining of the stabilizer sections 22 in a stabilizer assembly of the length of the present invention.
[0021] After the cylindrical sections 24 have been formed, the stabilizer sections 22 remaining on the tube 16 are machined to form the flutes 28 . This is done in a conventional manner, i.e. by rotating the blank slightly as it moves past the cutting implements.
[0022] The exterior surface of the ribs 26 are initially slightly smaller than the desired outer diameter of the stabilizer sections 22 . Hardbanding 38 is applied to the ribs 26 in a conventional manner, typically by electric arc welding of rods or wire including tungsten carbide particles so that the tungsten carbide particles are embedded in the hardbanding 38 . The thickness of the hardbanding 38 is sufficient to make the ribs 26 larger than the desired outer diameter. The stabilizer assembly 10 is then placed in a grinding machine or face plate lathe having centers sufficiently far apart to accept the assembly 10 and the surface of the stabilizer sections 24 ground or machined to remove enough hardbanding 38 to make the stabilizer sections 22 of the desired diameter. Prototypes of this invention have been made using a cylindrical grinder known as a Norton Model D Landis 36″×192″ S.N. 15684 that was last used as a grinder for drive shafts of submarines and other large marine vessels. At some time in the process of manufacture, the female threads 18 , 20 are machined into the ends of the blank.
[0023] As explained in U.S. Pat. No. 4,874,045, it is desirable to match the outside diameter of the bit 12 with the outside diameter of the stabilizer 14 so that the bit 12 is only slightly larger than the stabilizer assembly 14 . By either grinding the exterior of the bit 12 or by grinding the exterior of the stabilizer assembly 14 , the bit 12 ends up being 0.003-0.045 inches larger than the outside diameter of the stabilizer assembly 14 .
[0024] By making the stabilizer 10 of greater length, it is stiffer than a comparable joint of stabilizers threaded together. By making the stabilizer 10 balanced about its centerline, there is much less wobble or lateral motion of the stabilizer. Both modifications promote drilling of straight holes.
[0025] Although this invention has been disclosed and described in its preferred forms with a certain degree of particularity, it is understood that the present disclosure of the preferred forms is only by way of example and that numerous changes in the details of operation and in the combination and arrangement of parts may be resorted to without departing from the spirit and scope of the invention as hereinafter claimed.
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A stabilizer assembly is at least 12′ long and preferably at least 14′ long and is used to drill a straight bore hole in the earth. A central passage through the assembly closely follows a centerline as may be determined by measuring the wall thickness of the tube at a variety of locations in a single plane. At least three stabilizing sections are integral with the tube and include alternating ribs and flutes. Hardbanding on the ribs is ground down to tolerances with a grinding machine or face plate lathe having centers sufficient to receive the 12′ long stabilizer assembly.
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RELATED APPLCIATIONS
[0001] Applicants hereby claim priority under 35 USC §119 for U.S. provisional patent application Ser. No. 60/910,816 filed Apr. 9, 2007 and titled “FUEL OFFERING AND PURCHASE MANAGEMENT SYSTEM,” Attorney Docket No. 17209-076PV. The entire contents of the aforementioned application(s) are herein expressly incorporated by reference.
FIELD
[0002] The disclosure relates generally to commodity management systems and more particularly to apparatuses, systems and methods for facilitating the pricing, sales and delivery of a commodity or a commodity derivative to a customer.
BACKGROUND
[0003] The generally increasing and unpredictably fluctuating costs of vehicle fuels, for example automobile fuels, have impacted both private consumers and commercial businesses. Not only have fuel prices risen steadily over the long term at rates that significantly exceed the general cost of living, but fuel prices also suffer significant short-term fluctuations due both to predictable and unpredictable market forces.
[0004] Long-term, steady increases in fuel prices result from a variety of influencing factors, including growing depletion of fossil fuels, increasing costs associated with locating and developing raw fuel materials, increasing pricing demands made by oil-producing countries, and others as will be known to the reader.
[0005] Short-term price fluctuations in fuel prices can result from both predictable and unpredictable events. Summer travel is an example of a predictable market demand event that typically causes the price of vehicle fuel to fluctuate upwards at a time when the increased cost has the most significant effect on a typical purchaser. National and international conflicts and political unrests in and amongst oil-producing countries are examples of unpredictable events that often produce unexpected and volatile increases in crude and hence processed fuel products.
[0006] These price fluctuations have significantly impacted many purchasers. Automobile drivers find the cost of fuel prohibitive for both business commuting and optional travel. Airlines have been forced to significantly increase the cost of air transportation to accommodate rising fuel prices. Service providers dependent on fuel prices, for example taxis, trucking services, package delivery services and others have all been forced to increase prices to accommodate rising fuel prices.
[0007] Many consumers and commercial fuel users have taken significant steps to control or diminish their fuel consumption. More fuel-efficient vehicles have become available and put into use. Unnecessary travel or fuel usage may be curtailed. Carpooling and the use of public transportation have increased. These “green,” environmentally friendly efforts may result in lower fuel usage and hence lower fuel costs. However, they do not protect against the ongoing, steady, long-term rise in fuel costs. Neither do they offer significant help against unpredictable, short-term fuel price fluctuations.
[0008] In general, it is quite difficult if not impossible for parties dependent on fuel costs to plan and budget accurately and appropriately for the ever-changing price of fuel, particularly vehicle fuel. Some parties have engaged in pre-purchase programs of automotive fuel, which is stored at specified filling stations for subsequent pick-up and use by the parties. Such action require purchase and storage of the fuel, and require the parties to pick up the fuel from the storage location. For large, sophisticated commercial practitioners, hedging is another method of controlling the future cost of a commodity.
SUMMARY
[0009] The present disclosure is directed towards apparatuses, systems and methods to facilitate the pricing, sales and delivery of a commodity fuel to a Customer. In one embodiment, the disclosure teaches a Fuel Offer Generator that facilitates the purchase and management of fuel offerings. The Fuel Offer Generator allows Customers interested in securing fuel to obtain an offer for fuel at lock-in prices for various tenors. Fuel Customers can buy these fuel offers such that they may later exercise the fuel offers so their fuel costs are locked-in at desired levels (e.g., they may be set to strike prices). The Fuel Offer Generator also can establish a Premium Price that will be part of the fuel offer. The Fuel Offer Generator may generate hedges to counteract fuel related risks stemming from fuel offer purchases. Ultimately, a customer that purchases a fuel offering can exercise their fuel offering order at a specified price and redeem any difference between the market price for their purchased fuel and the price specified in their fuel offering order. The Fuel Offer Generator employs a geographical fuel pump location metric as well as consumer purchasing behavior to establish the pricing of fuel offerings.
[0010] In one embodiment, a method is disclosed for providing fuel offerings, the method comprising: setting at least one commodity offering terms for a commodity offering; determining at least one commodity offering pricing value based on the at least one commodity offering terms and at least one commodity offering pricing model for the commodity offering; providing the commodity offering, including at least one association based on the commodity offering pricing values between a strike price and a premium, for selection by a customer; providing payment for some portion of a commodity purchase for an exercised commodity offering, wherein the strike price of the commodity offering is less than a local retail commodity price; recording customer behavior, including selection and exercise of commodity offerings, in a customer behavior database; and modifying the at least one commodity offering pricing model based on the customer behavior database.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The accompanying appendices and/or drawings illustrate various non-limiting, example, inventive aspects in accordance with the present disclosure:
[0012] FIGS. 1A-B illustrate aspects of an embodiment of the Fuel Offering Generator;
[0013] FIG. 2 shows a top level information flow of a process for creating and managing the execution of fuel offerings to one or more Purchasers, according to one embodiment;
[0014] FIGS. 3A-B are of aspects of financial structure model operation in particular embodiments of Fuel Offering Generator operation;
[0015] FIGS. 4A-B illustrate operation of financial structure pricing and price-pump model operation in respective embodiments of Fuel Offering Generator operation;
[0016] FIGS. 5A-D illustrate operation aspects for some embodiments of the Fuel Offering Generator;
[0017] FIG. 6 illustrates a fixed volume aspect of fuel offerings in one embodiment;
[0018] FIG. 7 illustrates an aspect of fuel usage restrictions for fuel offerings in one embodiment;
[0019] FIG. 8 illustrates an aspect of cap restrictions for fuel offerings in one embodiment;
[0020] FIG. 9 illustrates an aspect of structural constraints of a fuel offering in one embodiment;
[0021] FIG. 10 illustrates one embodiment of SPZ map generation;
[0022] FIG. 11 illustrates further aspects of SPZ map generation and management in one embodiment;
[0023] FIG. 12 illustrates aspects of SPZ pricing in one embodiment;
[0024] FIGS. 13A-B illustrate aspects of withdrawal expiry restrictions on offerings in one embodiment;
[0025] FIG. 14 shows an overview of one aspect of the multi-SPZ fuel offering exercise in one embodiment;
[0026] FIG. 15 illustrates aspects of process flow for management of Purchaser profile incentives and/or penalties in one embodiment;
[0027] FIG. 16 illustrates further aspects of process flow for management of Purchaser profile incentives and/or penalties in one embodiment;
[0028] FIG. 17 illustrates further aspects of process flow for management of Purchaser profile incentives and/or penalties in one embodiment;
[0029] FIG. 18 illustrates further aspects of process flow for management of Purchaser profile incentives and/or penalties in one embodiment;
[0030] FIG. 19 illustrates aspects of process flow for management of retailer price group incentives and/or penalties in one embodiment;
[0031] FIG. 20 illustrates further aspects of process flow for management of retailer price group incentives and/or penalties in one embodiment;
[0032] FIG. 21 illustrates further aspects of process flow for management of retailer price group incentives and/or penalties in one embodiment; and
[0033] FIG. 22 is of a block diagram illustrating embodiments of the present invention of a Fuel Offering Generator system controller.
[0034] The leading number of each reference number within the drawings indicates the figure in which that reference number is introduced and/or detailed. As such, a detailed discussion of reference number 101 would be found and/or introduced in FIG. 1 . Reference number 201 is introduced in FIG. 2 , etc.
DETAILED DESCRIPTION
Fuel Offering Generator
[0035] FIG. 1A illustrates a system 100 for generating fuel offerings according to an embodiment of the Fuel Offering Generator. System 100 comprises a market parameter generator 408 coupled for real-time monitoring of data related to a fuel market 410 . Real-time market data refers to data reflecting current market conditions as trading in the market takes place. Examples of real-time market data provided to real-time market parameter generator 108 include wholesale over-the-counter fuel options market data, wholesale fuel options over-the-counter forward market and futures market data, and spot prices for retail fuel as well as spot prices for wholesale fuel. In an alternative embodiment, a market parameter generator may be configured to periodically and/or intermittently query current values for market parameters.
[0036] A market history analyzer 115 is coupled to receive and/or record observable real-time market data and/or historical records of market data related to market 110 . The market history analyzer may record and store observed market data and/or historical market data accumulated historically and received by the market history analyzer. In that manner, market history analyzer 115 develops data related to the historical performance of the market. In one embodiment of the Fuel Offering Generator, market data includes retail gas spot prices and wholesale gas spot prices.
[0037] A product matrix generator 125 is coupled to the market parameter generator 108 and to the market history analyzer 115 . Product matrix generator 125 is configured to the behavior of market 110 . Product matrix generator 125 operates on the parameters it receives from real-time market parameter generator 108 and market history analyzer 115 in accordance with a stochastic model of the dynamics of the market 110 . In one implementation, the product matrix generator 125 may consider some of the market variables and/or other input parameters in FIG. 4A and discussed below. Product matrix generator 125 may solve a stochastic differential equation to provide a commodity volatility model based on the input parameters.
[0038] In one embodiment, the matrix generator 125 is configured to solve stochastic differential equations for market models using parameters provided by real-time market parameter generator 108 and market history analyzer 115 . Among other parameters provided by real-time market parameter generator 108 and market history analyzer 115 , parameters reflecting retail fuel sales activity may be collected and provided to real-time market parameter generator 108 and market history analyzer 115 in embodiments of the Fuel Offering Generator.
[0039] For example, in one embodiment of the Fuel Offering Generator, the matrix generator 125 is configured to process spot price spread information provided by real-time market parameter generator 108 . The spot price spread information is related to a difference between a retail fuel spot price and a wholesale fuel spot price. Matrix generator 125 processes the spot price spread information in accordance with a stochastic model. In embodiments of the Fuel Offering Generator, the matrix generator 125 is further configured to process retail fuel forward curve parameters in accordance with a stochastic model. The retail forward curve parameters may be provided by the market history analyzer 115 . In another embodiment of the Fuel Offering Generator, the matrix generator 125 may further solve alternative market models that are adapted and/or deemed suitable for use in embodiments of the Fuel Offering Generator.
[0040] In one embodiment of the Fuel Offering Generator, the matrix generator 125 receives market parameters from real-time market parameter generator 108 and from market history analyzer 115 . Product matrix generator 125 processes and analyzes the information to provide a solution for the adapted stochastic differential equation. Product matrix generator 125 may be coupled to price information generator 130 and configured to provide the solution thereto. Based upon the solution it receives from product matrix generator 125 , price information generator 130 may provide data representing a product price at an output in one implementation. In an embodiment of the Fuel Offering Generator, the price information generator 130 may also provide data representing price sensitivity at an output. In one implementation, the price sensitivity may indicate price sensitivity not only with respect to wholesale fuel markets but also with respect to retail fuel prices, and/or with respect to other input variables received from real-time market parameter generator 408 , market history analyzer 405 , and/or product modeler 420 .
[0041] In one embodiment, the system 100 further comprises a product modeler 120 . Product modeler 120 is coupled to at least one computer system 102 . In some embodiments of the Fuel Offering Generator, the product modeler 120 is coupled to two computer systems 102 and 104 . In embodiments of the Fuel Offering Generator at least one of computer systems 102 and 104 comprises a fuel offering Purchaser computer. In some embodiments the fuel offering Purchaser computer may be coupled to product modeler 120 via a communications network, such as the Internet. A fuel purchaser may enter information related to a fuel product, such as a fuel offering, using the fuel offering Purchaser computer. The fuel offering Purchaser computer transmits the information to product modeler 120 . In one implementation, the product modeler 120 may use the information from the fuel offering Purchaser to determine features of a financial product to be modeled by product modeler 120 .
[0042] In one embodiment, the Fuel Offering Generator 100 comprises at least one Distributor computer system 104 . Distributor computer system 104 is coupled to product modeler 120 and may enable a Distributor to define characteristics of a financial product comprising fuel offerings to be offered to a consumer. In that embodiment a Distributor inputs data to Distributor computer 104 . Distributor computer 104 provides the data to product modeler 120 . Product modeler 120 models the financial product in accordance with the characteristics provided by Distributor computer system 104 .
[0043] Product modeler 120 is coupled to product matrix generator 125 . Based upon inputs from at least one of a fuel purchaser computer 102 and a Distributor computer 104 product modeler 120 generates data representing features of a financial product. System 100 determines the price of the financial product based upon product data provided by product modeler 120 , real-time market parameters provided by real-time market parameter generator and on historical market data provided by market history analyzer 115 .
[0044] In one embodiment of the Fuel Offering Generator, the matrix generator 125 is coupled to a consumer behavior modeler 170 . Consumer behavior modeler 170 receives data representing Purchaser (e.g., consumer) behavior with respect to fuel offering execution and/or purchase, ownership, exercising, and/or the like. Based upon the behavior data consumer behavior modeler 170 provides Purchaser and/or consumer behavior parameters to matrix generator 125 . In that embodiment, matrix generator 125 considers the Purchaser and/or consumer behavior in calculating price for a financial product.
[0045] FIG. 1B describes one embodiment of a Fuel Offering Generator 101 . In one implementation of the Fuel Offering Generator, a fuel offering comprises a product related to future purchases of fuel in a retail fuel market. Both the retail and the wholesale fuel markets are observed 103 . Observable wholesale fuel market parameters include wholesale fuel over-the-counter (OTC) options information, wholesale gas over-the-counter (OTC) forward market data in a wholesale fuel market. Fuel market data including retail fuel spot price information is obtained 103 .
[0046] Market parameters related to current market conditions are generated based on the observed fuel market condition 111 . At least one generated market parameter related to current market conditions is wholesale-retail spot price spread in one implementation. Other generated market parameters may include a wholesale implied volatility and a wholesale forward curve.
[0047] In one embodiment of the invention parameters related to current market conditions are sampled and stored to provide historical data describing past market behavior 113 . One sampled and stored parameter used in one implementation to provide historical data is retail fuel market spot price. Thus historical data related to retail fuel spot price is acquired.
[0048] Historical data, such as data related to retail fuel spot price, may be analyzed 119 . The analysis may, in one implementation, consider retail fuel market information. The data is used to estimate parameters of models for fuel market behavior 121 . Examples of generated fuel market behavior parameters may include retail implied volatility, wholesale mean reversion, retail forward curve and retail mean reversion. The indicators of fuel market behavior and the parameters related to current market conditions are analyzed 123 . In one embodiment of the Fuel Offering Generator, the analyzing step is carried out by stochastic modeling. Price information for the fuel offering is generated 143 . In one embodiment of the Fuel Offering Generator, price sensitivity information related to the fuel offering is generated 144 .
[0049] In further embodiments of the invention Purchaser and/or consumer behavior may be observed 141 . Data related to Purchaser and/or consumer behavior is obtained based on the observations. In one embodiment of the invention Purchaser and/or consumer behavior data is analyzed 142 as considered in an analyzing step 123 as a factor in generating price information 143 .
[0050] Fuel Offering Generator Information Flow
[0051] With reference now to FIG. 2 , there are shown and described a top level information flow of a process for creating and managing the execution of fuel offerings to one or more Purchasers, according to one embodiment.
[0052] FIG. 2 is seen to include three principal parties including a Provider 202 of fuel offerings, a Distributor 204 of fuel offerings and at least one Purchaser 206 of fuel offerings. It will be understood that in certain embodiments, the Provider 202 and Distributor 204 may be considered as a single entity from the perspective of the Purchaser 206 . It will also be understood that while FIG. 2 illustrates a single Purchaser 206 , for ease of explanation, the single Purchaser 206 is representative of a marketplace of potential Purchasers 206 of the fuel offering.
[0053] At block B 1 , a request is made by the Distributor 204 , directed to the Provider 202 , to structure and/or generate one or more fuel offerings. In some embodiments, the request may include some number of product factors and/or parameters, for example, (i) the type of fuel to offered, (ii) the quantity of fuel to be offered, (iii) usage per period limitations, (iv) tenor, (v) geography, and/or (vi) strike price. Of course, in other embodiments, other combinations and/or additional factors and/or parameters may alternatively or additionally be provided.
[0054] At block C 1 , the Provider 206 structures a selection of fuel offerings, responsive to the Distributor 204 request. The selection of fuel offerings may, in one embodiment, include associated premiums based on the parameters provided by the Distributor 204 . In certain embodiments, the selection of fuel offerings may constitute a single fuel offering or a range of fuel offerings, as shown in Table 1 below. Depending on the embodiment, a fuel offering may be characterized its type (e.g., fuel type, such as regular unleaded gasoline, premium unleaded gasoline, diesel, bio-diesel, ethanol, hydrogen and/or the like), strike price, tenor or term (e.g., 3 months, 6 months, 1 year, etc.), calculated premium and/or the like. Table I, illustrates, by way of non-limiting example, an exemplary range of fuel offerings which may be constructed by the Provider 206 , responsive to a Distributor 204 request.
[0000]
TABLE 1
Type
Quantity
Strike Price
Tenor
Premium
Diesel
30k gallons
$2.50
3 months
$0.40
Diesel
30k gallons
$2.75
3 months
$0.30
Diesel
30k gallons
$3.00
3 months
$0.20
Diesel
30k gallons
$3.25
3 months
$0.10
[0055] With continued reference to FIG. 2 , at block C 2 , the range of fuel offerings, such as those shown in Table 1, are presented to the Distributor 204 for his or her approval and/or selection.
[0056] At block B 2 , the Distributor 204 , may select one or more fuel offerings and make said offering(s) available to Purchasers 202 . In one embodiment, it is contemplated that the fuel offering(s) may be made widely available over to a large population of potential Purchasers over an electronic network, such as the Internet. In the case where the Distributor 204 does not select one or more fuel offerings, the process may return to block C 1 and the fuel offerings may be re-structured in an appropriate manner.
[0057] At block B 3 , the Distributor 204 may pay the Provider 206 an upfront strike price plus premium and/or service markup, or otherwise paying only a premium and/or service markup.
[0058] At block C 3 , the Provider 206 may protect its fuel offering investment by employing hedging strategies, such as, for example, utilizing forward contracts, futures, wholesale fuel options and/or the like in appropriate combination(s). In some embodiments, the Provider 206 may alternatively elect not to employ any hedging strategies.
[0059] At block A 1 , a Purchaser 202 may access the Distributor 204 (e.g., via a web-site) to purchase one or more fuel offerings being marketed by the Distributor 204 . For example, with reference again to Table I, a Purchaser 202 may elect to purchase the first listed fuel offering (see row 1 of Table I),
[0000]
Type
Quantity
Strike Price
Tenor
Premium
Diesel
30k gallons
$2.50
3 months
$0.40
[0060] At block A 2 , the Purchaser 202 , in possession of the fuel offering shown above, may exercise the fuel offering to purchase fuel (in this case, diesel fuel) up to the stipulated quantity, during the indicated tenor, and at the indicated strike price. Additional details of the transaction may be dependent upon the model being utilized by the Distributor 204 (e.g., based on a national average price or a pump price). For example, in some embodiments, when a Purchaser 202 purchases fuel, the Distributor 204 may pay the difference between the strike price ($2.50), and either the pump price at the point of purchase or a national average price on the date of purchase. In one embodiment, the fuel offering is priced to include the strike price plus the premium, so that upon exercising the fuel offering (i.e., buying gas), the Purchaser 202 pays out no money, and the fuel retailer is paid by the Distributor 204 . As a further example, in accordance with one implementation of the pump price model, if the pump price is $3.00 and the fuel offering strike price is $2.50, the Purchaser 202 effectively pays $0.10 less than the pump price, considering a premium payment of $0.40, which is advantageous to the Purchaser 202 .
[0061] At block B 4 , in response to the Purchaser 202 purchasing fuel at block A 2 within the construct of the fuel offering, the Distributor 204 pays the fuel retailer (e.g., gas station) at the point of purchase the cost of the gasoline based on the pump price on the date of purchase. In an alternative embodiment wherein the Purchaser has only paid a premium and not a strike price to the Distributor up front, the Distributor may only pay based on the difference between the pump price and the fuel offering strike price to the gas station.
[0062] At block B 5 , the Distributor collects feedback data on each fuel offering exercise and/or purchase, such as the one described at block A 2 and said data is provided to the Provider 206 to enable refinement of future fuel offerings. The collected data may include the prices at which Purchasers are exercising fuel offerings (e.g., purchasing fuel) relative to the corresponding fuel offerings strike prices, the quantities involved and/or other indicia.
[0063] At block C 4 , the Provider pays the Distributor the cost of the gasoline for which the Distributor has paid the gas station. In an alternative embodiment, the Provider may only pay the difference between the cost of the gasoline and the cost calculated based on the fuel offering strike price.
[0064] Financial Structure Model
[0065] FIGS. 3A-B show aspects of financial structure model operation in particular embodiments of Fuel Offering Generator operation. In FIG. 3A , a combined logic and data flow diagram is shown illustrating one implementation of the financial structure model. A pricing module 301 receives as inputs fuel market information 303 , historical analysis 305 , and offering parameters 310 . Details surrounding the nature of these inputs, including examples thereof, and of pricing module operation, will be discussed in greater detail in the context of offering pricing below. The pricing module yields as output at least one offering price and/or price matrix 320 , that may be comprised of one or more offerings with associated strike price, premium, tenor, terms, service markup, restrictions, constraints, discounts, and/or the like. The pricing module may also yield as output at least one set of sensitivity data characterizing the sensitivity of price matrix elements to input parameters. For example, the sensitivity data may delineate, among other things, the sensitivity of the premium of a given offering or set of offerings to fuel market factors, such as retail gasoline spot prices. Sensitivity may be represented, in one implementation, by the first derivative of the output variable (e.g., offering price, premium, strike price, etc.) with respect to an input variable (e.g., market factors, historical factors, offering parameters).
[0066] The Provider determines at 330 whether the price matrix 320 is satisfactory based on a set of price matrix satisfaction criteria, which may include a consideration of the reasonableness of premium value and strike price combinations. Price matrix satisfaction criteria may also be based in part on accumulated Purchaser (e.g., consumer) marketing research data 333 , such as data describing which offerings, premium and strike price combinations, etc. are most attractive to Purchasers, which types of offerings are least likely to be exercised, and/or the like. If the price matrix 320 output by the pricing module 301 is not satisfactory based on the satisfaction criteria, then the offering parameters 310 may be adjusted in order to improve the alignment of the pricing matrix with the satisfaction criteria in the next iteration. If, on the other hand, the pricing matrix does meet a minimum standard of satisfaction, then the corresponding offerings are made available in a Purchaser market, such as a consumer market 335 . Purchasers may execute purchases of offerings 340 and, subsequently, exercise the offerings 345 to receive pay-outs consistent with offering terms.
[0067] In one implementation, the Provider itself may price offerings, make them available to a Purchaser market, execute Purchaser offering purchases, and honor Purchaser offering exercises. In another implementation, the Provider may price offerings and make them available to an intermediary Distributor entity, who may provide them to a Purchaser market and interface with Purchasers for offer purchases and exercises. Additional details surrounding Provider-Distributor-Purchaser interactions in the context of offering exercise delays are discussed below.
[0068] Data related to offering executions and exercises (e.g., offering popularity, exercise rates, and/or the like) may be monitored by the Provider and incorporated into a Purchaser marketing research data set that may be sampled in subsequent selection of offering parameters. For example, the Provider may observe that all 3-month tenor, regular octane gasoline offerings having a strike price of $2.90/gallon and up sell considerably more poorly than other offerings regardless of the premium charged. Subsequent offering generations may, consequently, exclude these offering parameters and/or terms altogether. Offering exercise information may also be fed back into the pricing module through historical analysis variables that may alter the strike price and/or premium of particular offering rather than changing the presence or absence of offering parameters altogether. For example, the Provider may observe that the profits derived from 12-month tenor, regular octane gasoline offerings having a strike price of $2.00/gallon are greater than expected because Purchasers who exercise these particular offerings tend to behave sub-optimally. Consequently, the system may incorporate that knowledge to charge a lower premium for these particular offerings that may attract more Purchasers to these types of offerings and potentially increase the profits derived from them even more.
[0069] Data related to execution 340 and exercise 345 of offerings may also be incorporated, along with sensitivity data 325 , into Provider hedging strategies and/or practices 350 . In an effort to offset, mitigate, and/or eliminate some amount of risk associated with the sale of offerings, the Provider may elect to select, purchase, and/or manage a portfolio of hedging instruments. A Provider devised hedging portfolio may be comprised of a variety of different types of holdings in various implementations that may include but are not limited to equities, debts, derivatives, synthetics, notes, stocks, preferred shares, bonds, debentures, options, futures, swaps, rights, warrants, commodities, currencies, long and/or short positions, ETFs, and/or other assets or investment interests. In one implementation, a Provider devised hedging portfolio may be comprised of forward contracts and/or futures of exchange or over-the-counter (OTC) traded wholesale fuel options, gasoline options, and/or the like. Sensitivity data 325 provides information describing the degree to which a particular input variable (e.g., a market parameter) affects the strike price and/or premium of an offering. Counteracting the risk associated with an offering may, therefore, be accomplished by seeking instruments whose sensitivity to input variables is similar in magnitude but opposite in direction to offering sensitivities. Observed offering execution and exercise practices and/or trends of Purchasers may further affect Provider hedging strategies and/or practices. For example, an observation of sub-optimal exercise of offerings by Purchasers may indicate to a Provider that a smaller purchase of hedging instruments will suffice to offset the risk associated with the offerings. In the extreme case, wherein the offerings are never exercised under any circumstances, the Provider would have no need for hedging instruments at all. Further details surrounding hedging strategies and/or practices in the context of Purchaser aggregation and scale are discussed below.
[0070] FIG. 3B shows logic flow in an implementation of the financial structure model in one embodiment of Fuel Offering Generator operation. A Provider collects financial structure model inputs 360 , such as market factors, average and/or specific fuel prices, price and/or market factor geographic distributions, historical price data and/or market factors, offering parameters (e.g., strike price, premium, tenor, restrictions, discounts, incentives, and/or the like), Purchaser and/or consumer behavior considerations, hedging strategy considerations, and/or the like and stores them in a variables table at 365 . Based at least in part on financial structure model inputs, the Provider may determine a price matrix 370 . Model inputs, outputs, and price matrix determination logic will be discussed in greater detail below. In one implementation, a price matrix may be comprised of a collection of offerings with varying terms, strike prices, premiums, incentives, restrictions, and/or the like. In one implementation, the Provider and/or the Distributor may further append a service markup to the strike price and/or premium to yield an offering price and/or collection of offering prices within a consumer price matrix.
[0071] The Provider may send 375 a price matrix, consumer price matrix, and/or some portion thereof 376 to Purchasers for consideration and, for any Purchasers who request to purchase offerings, the Provider may subsequently receive notices of offering purchases 380 and execute offerings. These executed offerings may be sorted 383 and subsequently aggregated 385 into a plurality of similarity classes based on some desired criteria, such as Purchaser location, selected offering parameters and/or terms, Purchaser characteristics and/or demographics, Purchaser behavior and/or history, and/or the like. A sensitivity and/or risk analysis 388 may be performed on the similarity classes in order to determine sensitivity of offering prices to various input parameters (such as described above) and risk characteristics that may be considered in a hedging strategy for subsequent hedging of Provider risks and/or obligations. In addition, the Provider may optionally perform correlation analysis 390 on similarity classes, similarity class sensitivities, and/or similarity class risks in order to determine which, if any, similarity classes exhibit similar sensitivity and/or risk characteristics and/or correlations. Similarity classes with correlated sensitivity and/or risk behaviors may then be aggregated to simplify and/or expedite Provider hedging strategies.
[0072] The Provider may subsequently implement hedging strategies and/or accumulate a hedging portfolio 395 . In one implementation, Provider hedging strategies may be based in part on execution of Purchaser offering purchases, Purchaser offering exercises, and/or other Purchaser behaviors (e.g., Purchaser irrationality, and/or the like) at different scales of Purchaser granularity. In one implementation, Provider hedging strategies may be based in part on individual Purchaser offering purchases and/or exercises. For example, a large institutional Purchaser (e.g., a trucking company) may purchase a large enough offering and/or quantity of smaller offerings to motivate a Provider to develop a hedge strategy based solely on the single Purchaser purchase and/or behavior. In another implementation, Provider hedging strategies may be based in part on aggregated Purchaser offering purchases and/or exercises. For example, in this implementation, a Purchaser's offering purchase of a small quantity of gasoline may not affect the Provider's hedging strategy and/or portfolio. Instead, the Provider may enter a record of the offering purchase into a purchase repository for temporary storage and/or aggregation with other fuel offerings. The Provider may then periodically analyze purchase repository contents in order to determine when there is an aggregation of Purchaser offering purchases that is sufficiently large and/or significant to warrant consideration in the Provider hedging strategy and/or modification of the Provider devised hedging portfolio. Aggregation of Purchaser offering purchases may be made in a variety of different ways within various implementations. In one implementation, Purchaser offering purchases may be aggregated based on time of purchase. In another implementation, Purchaser offering purchases may be aggregated based on Purchaser characteristics (e.g., demographics, location, Purchaser behavior profile, and/or the like). In another implementation, Purchaser offering purchases may be aggregated based on the nature of Purchasers (e.g., individual Purchasers, small business Purchasers, large business Purchasers, government/institutional Purchasers, and/or the like). In another implementation, Purchaser offering purchases may be aggregated based on the risk characteristics associated with Purchasers and/or Purchaser characteristics. In addition to storing execution of Purchaser offering purchases for aggregation, a Provider may additionally or alternatively store exercise of Purchaser offerings for aggregation and subsequent consideration in hedging strategies.
[0073] The Provider may monitor and/or track Purchaser offerings to determine if offerings are exercised 3100 . If a Purchaser has exercised a purchased offering, then the Provider may query the circumstances of the Purchase exercise and pay-out the Provider's obligation under the terms of the offering in light of those circumstances 3105 . Circumstances may include location, time, fuel price (e.g., the average price of gasoline in a region wherein the offering was exercised, a regional or national average fuel price, and/or the like), status of Purchaser owned offering and/or offering restrictions at the time of purchase (e.g., whether the Purchaser has exceeded a monthly cap, whether the Purchaser is in a restricted region, and/or the like), and/or the like. In one implementation, the Provider may determine the Purchaser owned offering's strike price and a reference fuel price at the time of offering exercise and, if the strike price is less than the reference fuel price, determine the difference between those prices, multiply that difference by the volume of gas on which the offering is being exercised, and implement any additional discounts, penalties, or restrictions in order to determine the payout amount. In one implementation, the reference fuel price is a regional average fuel price. In another implementation, the reference fuel price is a national average fuel price. The Provider may also collect and/or analyze Purchaser behavior characteristics 3110 . The Provider may recollect and/or update financial structure model inputs at 3115 . The Provider may also store collected and/or analyzed Purchaser behavior characteristics in a Purchaser table 3120 .
[0074] In alternative implementations, a Provider may interface with Purchasers through an intermediary Distributor entity. In such an implementation, the Provider at 375 and/or 376 may send a pricing matrix or portion thereof to the Distributor, who may then optionally select elements of the price matrix and/or add a service markup to create a consumer price matrix for subsequent presentation to Purchasers. Purchasers who wish to purchase offerings may request offerings from the Distributor and offer payment based on the corresponding entries in the consumer price matrix. The Distributor, in turn, may relay purchase requests to the Provider 380 and/or purchase offerings from the Provider, and relay those offerings back to the Purchasers. When a Purchaser exercises an offering 3100 , the Distributor may pay-out to the Purchaser to regain ownership of the offering and immediately submit an exercise notice to the Provider to receive pay-out therefrom. Alternatively, a Distributor may pay-out obligations to Purchasers when offerings are exercised by those Purchasers, retake ownership of those offerings, and yet retain ownership until some later time at which an exercise notice is submitted to the Provider. Such a delay may allow the Distributor to take advantage of subsequent market changes (e.g., increases in fuel prices) that are foregone by suboptimal exercise of offerings by Purchasers. Such delay between Purchaser and Distributor offering exercise and/or suboptimal exercise by either Purchaser or Distributor may be considered by the Provider in pricing matrix generation and/or hedging strategies.
[0075] Financial Structure Pricing
[0076] FIGS. 4A-B show operation of financial structure pricing and price-pump model operation in respective embodiments of Fuel Offering Generator operation. FIG. 4A shows processing flow for pricing of offerings in one embodiment of Fuel Offering Generator operation. A collection of module inputs 401 may comprise current fuel market information 403 , historical fuel market information and/or analysis 405 , and observable 410 and non-observable 415 parameters derived therefrom. Some examples of possible current fuel market information 403 may include current wholesale gasoline OTC options market data, current wholesale gasoline OTC forward market and futures market data, current retail gasoline spot prices, and/or the like. Some examples of possible historical market information and/or analysis 405 may include historical wholesale gasoline OTC options market data, historical wholesale gasoline OTC forward market and futures market data, historical retail gasoline spot prices, historical wholesale gasoline spot prices, correlations between historical retail and wholesale gasoline prices, and/or the like. Some examples of observable parameters 410 that may be derived from current fuel market information may include wholesale gasoline implied volatilities, wholesale gasoline forward curves, spread of retail over wholesale spot prices, and/or the like. Some examples of non-observable parameters 415 that may be derived from historical fuel market information and/or analysis may include retail gasoline implied volatilities, wholesale gasoline mean reversion parameters, retail gasoline mean reversion parameters, retail gasoline forward curves, and/or the like.
[0077] In one implementation, the pricing module may also admit as inputs a collection of Purchaser historical data. Purchaser historical data may be comprised of records of Purchaser execution and/or exercise of offerings. In particular, the system may monitor Purchaser execution and/or exercise of offerings with specific attention to particular Purchaser behavior flags. In one implementation, a Purchaser behavior flag may comprise consistent solicitation of and/or exercising of offerings at more expensive than average fuel retailers. In another implementation, a Purchaser behavior flag may comprise consistent solicitation of and/or exercising of offering at cheaper than average fuel retailers. In another implementation, a Purchaser behavior flag may comprise too optimal a pattern of offering exercising. In another implementation, a Purchaser behavior flag may comprise too suboptimal a pattern of offering exercising. In another implementation, a Purchaser behavior flag may comprise strong time dependence of Purchaser exercising of offerings. If the number of observed Purchaser behavior flags exceeds a threshold minimum value, a Purchaser behavior history variable admitted as input to the pricing module may be adjusted so as to cause the pricing module to yield an adjusted pricing matrix intended to correct and/or direct future Purchaser behavior.
[0078] In addition to the aforementioned factors and variables, the pricing module may admit a collection of offering parameters that may specify offering terms presented to a Purchaser. Some examples of possible offering parameters may include strike price, premium, tenor, constraints, restrictions, incentives, discounts, fuel type, geographic location, and/or the like. In one implementation, a pricing module operator (e.g., Provider) may set values for some offering parameters and receive others as outputs from the pricing generator. For example, a particular desired strike price, tenor, set of restrictions, fuel type, and location may be input to the pricing module, and a premium received as an output from the module. Alternatively, a particular desired premium, tenor, set of restrictions, fuel type, and location may be input to the pricing module, and a strike price received as an output from the module. The particular mode of operation, including selection of offering parameter inputs and outputs, may be varied within different implementations depending on the particular goals and/or requirements of particular applications of the system.
[0079] Values for a selected group of module inputs 401 may be fed into the pricing module 301 for processing. Inputs are incorporated into an offering pricing model 425 such as, in one implementation, a commodity volatility model incorporated into a stochastic differential equation describing commodity value. An example of such a model is provided in U.S. Pat. No. 7,065,475 entitled, “Modeling Option Price Dynamics,” filed on Oct. 31, 2000, which is incorporated in its entirety herein by reference. U.S. Pat. No. 7,980,960 entitled, “System and method for providing a fuel purchase incentive,” filed on Mar. 28, 2001, and U.S. application Ser. No. 09/853,196 entitled “System and method for providing a fuel purchase incentive with the sale of a vehicle,” filed May 11, 2001, are each incorporated in their entirety by reference. Solving a stochastic differential equation to extract output offering parameters may be accomplished by a variety of techniques in different embodiments, such as but not limited to grid pricing, Monte Carlo simulation, analytic formulas, and/or the like.
[0080] In one implementation, the XML for module inputs may take the following form:
[0000]
<module_inputs>
<observables>
<WG_implied_vol> Jan08-Mar08, 30%,
Apr08-Dec08, 25%
</WG_implied_vol>
<WG_forward_curve> Jan08-Jun08, $2/gal,
Jul08-Dec08, $2.2/gal
</WG_forward_curve>
<Retail_wholesale_spot_spread> $0.8/gal
</Retail_wholesale_spot_spread>
</observables>
<non-observables>
<RG_implied_vol> 20%
</RG_implied_vol>
<WG_mean_reversion> 0.5
</WG_mean_reversion>
<RG_mean_reversion> 0.5
</RG_mean_reversion>
<RG_forward_curve> $2.9/gal
</RG_forward_curve>
</non-observables>
<offering_parameters>
<premium> $0.15/gallon </premium>
<tenor> 3 months </tenor>
<restrictions>
<total_volume> 60
gallons </total_volume>
<cap> 20 gallons/month </cap>
</restrictions>
<fuel_type> “regular” gasoline
(87 octane) </fuel type>
<location> New York Metro </location>
<index> New York Metro Average published
by DOE</index>
</offering_parameters>
</module_inputs>
[0081] The pricing module 301 subsequently outputs sensitivity data 435 and price data 440 . Price data 440 may, as discussed above, be comprised of different offering parameters depending on the requirements and consequent module inputs within a particular implementation. Thus, the price data 440 output may include, but is not limited to, strike price, premium, tenor, restrictions, usage constraints, incentives, fuel type constraints, geographic constraints, and/or the like. Sensitivity data 435 , as discussed above, describes the extent to which price data 440 may vary as module inputs 401 are varied. In one implementation, sensitivity data may be comprised of the first derivative of a price data variable with respect to one or more module input variables.
[0082] In one implementation, the XML for module outputs may take the following form:
[0000]
<module_outputs>
<sensitivity_data>
<WG_implied_vol_sensitivity> Jan08-Jun08, $1000 per
percent vol move, Jul08-Dec08, $500 per percent vol move
</WG_implied_vol_sensitivity >
<WG_forward_curve_sensitivity > Jan08 - Jun08, $500 per
$1/gal move, Jul08-Dec08, $750 per $1/gal move
</WG_forward_curve_sensitivity >
<Retail_wholesale_spot_spread_sensitivity > $3000 per $1/gal
move
</Retail_wholesale_spot_spread_sensitivity >
<RG_implied_vol_sensitivity >$1500 per percent vol move
</RG_implied_vol_sensitivity >
<WG_mean_reversion_sensitivity > $200 per 0.1 move in
mean-reversion
</WG_mean_reversion_sensitivity >
<RG_mean_reversion_sensitivity >$150 per 0.1 move in
mean-reversion
</RG_mean_reversion_sensitivity >
<RG_forward_curve_sensitivity > Jan08 - Jun08, $700 per
$1/gal move, Jul08-Dec08, $600 per $1/gal move
</RG_forward_curve_sensitivity >
</sensitivity_data>
<price_data>
<strike_price> $2.89/gallon </strike_price>
</price_data>
</module_outputs>
[0083] The pricing module output described by the above XML includes a single strike price within the price_data/strike_price field. In an alternative implementation, a Provider may determine price_data for a variety of module input values in order to yield an array of price_data with different corresponding offering parameters. Such an array of price data with corresponding offering parameters may be incorporated into a pricing matrix. In one implementation, the XML for a three-offering pricing matrix may take the following form:
[0000]
<pricing_matrix>
<offering1>
<strike_price> $2.89 </strike_price>
<premium> $0.15/gallon </premium>
<tenor> 3 months </tenor>
<restrictions>
<total_volume> 60 gallons </total_volume>
<cap> 20 gallons/month </cap>
</restrictions>
<fuel_type> “regular” gasoline (87 octane) </fuel type>
<location> New York Metro </location>
<index> New York Metro Average published by
DOE</index>
</offering1>
<offering2>
<strike_price> $3.02 </strike_price>
<premium> $0.10/gallon </premium>
<tenor> 3 months </tenor>
<restrictions>
<total_volume> 60 gallons </total_volume>
<cap> 20 gallons/month </cap>
</restrictions>
<fuel_type> “regular” gasoline (87 octane) </fuel type>
<location> New York Metro </location> </offering2>
<index> New York Metro Average published by
DOE</index>
</offering2>
<offering3>
<strike_price> $2.94 </strike_price>
<premium> $0.15/gallon </premium>
<tenor> 6 months </tenor>
<restrictions>
<total_volume> 60 gallons </total_volume>
<cap> 20 gallons/month </cap>
</restrictions>
<fuel_type> “regular” gasoline (87 octane) </fuel type>
<location> New York Metro </location>
<index> New York Metro Average published by
DOE</index>
</offering3>
</pricing_matrix>
[0084] Pump-Price Model and Pricing
[0085] FIG. 4B shows logic flow for determination of offering pricing within a pump-price model context in one embodiment of Fuel Offering Generator operation. Although geography is not necessarily central to the price structure itself, it is relevant, and greater detail about the may be found in FIGS. 10-11 . In this embodiment, the strike price associated with an offering is compared with the price charged by the particular fuel retailer at which an offering is exercised in assessing the extent of pay-out obliged to an exercising Purchaser. For example, in a non-prepay embodiment wherein a Purchaser has only paid a premium upfront, if a Purchaser exercises an offering based on a strike price of $2.20 for a gallon of gasoline at a retailer that charges $2.40/gallon, the Purchaser may be refunded $0.20/gallon by the Provider, while the same offering exercised at a retailer charging $2.55 would yield $0.35/gallon if exercised. In an alternative, prepay embodiment wherein a Purchaser has paid both strike price and premium up front, the Provider would directly pay the gas station the cost of the fuel based on either the $2.40 or $2.55 pump prices. Due in part to the pump-specific sensitivity of this model, a number of additional restrictions and/or structural considerations, such as management of geographic price variations and undesirable Purchaser behavior, may be implemented to facilitate desired Generator operation and will be described in greater detail below. These factors may, in one implementation, be incorporated into determination of up-front pricing (e.g., premiums) for fuel offerings. They may also, or in an alternative implementation, be considered as part of fuel offering redemption structure as discussed below and in FIGS. 10-12 and 14 - 21 .
[0086] Owing to the dependence of pump-price model payout on the price at the pump itself, considerations of variability between pump prices in different geographic regions must be incorporated. The Generator develops a Single-Price Zone (SPZ) map at 445 , wherein an SPZ is defined as a region and/or collection of retailers defined by a single, uniform pricing assignment. For example, a Purchaser may exercise an offering with the same strike price at a given premium at all retailers belonging to the same SPZ. SPZ map determination is described in greater detail below in FIGS. 10-11 . The SPZ map defines SPZ boundaries and may guide the accumulation of historical pump price distribution data for a given SPZ 450 . Historical Purchaser bias data may also be accumulated for a given SPZ 455 . Purchase bias data may, in one implementation, describe the extent to which Purchasers tend to exercise offerings at retailers that are biased to one side or the other of the average of retailers within the SPZ. For example, a large Purchaser bias may indicate that Purchasers tend to exercise their offerings disproportionately often at expensive fuel retailers. The SPZ map and accumulated data may be employed to determine and/or collect further factors relevant to pricing within the pump-price model 460 . These factors may include the size of Purchaser bias with an SPZ, volatility of that bias, convexity of that bias, and the existence of a no-arbitrage condition. Convexity of bias in this context may, in one implementation, be construed to describe the extent to which there is a difference in the average pay-out amount between those offerings based on the difference between strike price and an average retailer pump price and those offerings based on the difference between a strike price and a pump price at which the offering is exercised. Volatility of bias reflects the extent to which the distribution of prices within an SPZ may vary over time and the effect of such variation on deviations of Purchaser behavior from average expectations. The no-arbitrage condition in this context may, in one implementation, be construed to describe the avoidance of a situation where a Purchaser can buy an offering and immediately exercise to make riskless profit. These and other factors discussed may affect the cost of offerings and, consequently, be considered in either the up-front pricing (e.g., premium) of offerings, or in the devising of incentives, restrictions, discounts, and penalties. A financial structure pricing determination is performed at 465 , similar to those described above in the context of the financial structure pricing model above, and the output premium and/or strike price is adjusted by an amount determined by the factors in 460 to yield a pump-price pricing 470 .
[0087] An example of a premium adjustment made as part of the price-pump model may be to determine the average pump price within an SPZ, compute the total payout for an offering exercised at all retailers charging higher than that average, divide by the total number of retailers, and add this quantity (the convexity of bias, in one implementation) directly to the premium. Another example of a premium adjustment made as part of the price-pump model may be to determine the standard deviation of average retailer pump prices within an SPZ over some period of time and add that deviation, or some fraction thereof, to the premium. Further premium and/or strike price adjustments may be implemented within different embodiments of the Fuel Offering Generator.
[0088] Based on the SPZ map developed in 445 , the Generator may determine current and/or historical variability of basis (i.e., difference) between SPZ premiums and/or strike prices for a given collection of SPZs, such as a collection that is incorporated as part of a Purchaser offering. Based on that information, the Generator may yield strike price and/or premium adjustments and/or a premium adjustment table, as described in greater detail in FIGS. 10-14 . The adjustment of premium price based on geographic considerations and/or the generation of a premium adjustment table may be relevant, in one implementation, to only those fuel offerings that cover fuel purchases made in multiple SPZs.
[0089] Customer Interaction Flow
[0090] FIG. 5 illustrates an aspect of purchase and fuel offering exercise for one embodiment of the Fuel Offering Generator. Prior to discussing process FIG. 5 in detail, it is instructive to first review, in a broad sense, the Purchaser's perspective of Fuel Offering Generator. The Purchaser may be an entity who desires to purchase fuel offering to mitigate fuel costs over some period of time. In accordance with this goal, a number of fuel offerings may be made available for purchase by the Distributor. A fuel offering may include specific details regarding the terms and conditions, as shown in the below example.
[0000]
Type
Quantity
Strike Price
Tenor
Premium
Diesel
30k gallons
$2.50
3 months
$0.40
[0091] The example fuel offering has a tenor of three months, during which the Purchaser may exercise the fuel offering on up to 30 k gallons of diesel fuel at a strike price of $2.50. The premium may, in some embodiments, represents the measure of risk associated with the fuel offering, i.e., higher premiums may correlate to higher risk fuel offerings. By purchasing the fuel offering shown above, the Purchaser mitigates the risk of fuel costing in excess of $2.90 (strike+premium) over the three month tenor. That is, by purchasing the fuel offering, the Purchaser pays $0.40 for the ability or right to purchase fuel for $2.50, up to the stipulated number of gallons (e.g., 30 k). In some embodiments, an offer price of $2.90 (strike+premium) may represent the Purchaser's effective purchase price for any purchase made within the 3 month period for up to 30 k gallons of fuel if the cost of fuel over that three month period exceeds the offer price. As is apparent to the astute reader, exercising the fuel offering does not clearly provide economic benefit to the Purchaser for prevailing pump prices and/or national average prices below $2.90, though it may still be beneficial to the Purchaser to exercise the offering between $2.50 and $2.90 because the premium is, at that point, a sunk cost.
[0092] As shown in FIG. 5 , the Purchaser purchases a fuel offering with a particular strike price for certain fuel volume (N) 505 . At some point subsequent to the purchase of the fuel offering, the Purchaser may decide to purchase X gallons of fuel 510 . In so doing, the Purchaser may elect to exercise the offering on the fuel purchase of X gallons or not 515, generally depending upon the pump price of fuel at the time of purchase. In the case where the cost of fuel is less than the strike price, it does not make economic sense for the Purchaser to exercise the offering, for reasons described above, and in such a situation, the Purchaser may simply pay the prevailing pump price 525 . Alternatively, in the case where the cost of fuel is greater than the strike price, particularly where the cost of fuel is greater than the strike price+premium, it may make economic sense to exercise the fuel offering 520 , though the Purchaser may not necessarily exercise the fuel offering (e.g., if the Purchaser expects the cost of fuel to be even higher the next day). In some embodiments, the fuel offering may be automatically exercised whenever the cost of fuel is greater than the strike, or alternatively, the strike+premium. In another embodiment, the fuel offering is not exercised automatically. If the Purchaser decides to exercise the fuel offering 515 , the Purchaser profile (e.g., a data file that includes information regard the Purchaser's fuel offering(s)) or like information source regarding the fuel offering may be queried to determine the unused fuel volume (R) remaining for the fuel offering 520 . A determination is then made as to whether the remaining volume (R) is equal to or greater than purchase volume (X) 530 . If not, then the Purchaser pays the prevailing pump rate 525 for the full purchase. In another embodiment the Purchaser may be able to exercise the fuel offering for a partial amount of the full purchase (i.e., for the remaining volume). Otherwise, a determination is made regarding whether the prevailing pump price (or other price, such as the national average price, as indicated by the implementation) is greater than the strike price 540 . If so, the Purchaser's account is credited with the difference (D) between the strike price and the pump price, multiplied by the number of gallons (X) purchased 545 . Otherwise, in the case where the prevailing pump price is determined to be less than the strike price 540 , the Purchaser pays the prevailing pump price 550 .
[0093] FIG. 5B provides an example strike vs. exercise graph for one embodiment of the Fuel Offering Generator. The strike 552 is the strike price (e.g., $1.50) of the fuel offering and the exercise boundary 553 represents the price over which exercise of the fuel offering is approximately economically optimal over the tenor (e.g., 6 months) of the offering. The exercise boundary 553 is initially the strike 552 plus an initial boundary and decreases to the strike at the end of the tenor of the offering. In some embodiments, the optimal initial boundary is found by maximizing the average pay-out across a range of initial boundaries, and the resulting exercise behavior (e.g., economically optimal exercise) used to model Purchaser behavior, including average pay-out.
[0094] FIGS. 5C and 5D provide further illustrate payout aspects for some embodiments. FIG. 5C provides a flow diagram for an embodiment in which the Purchaser prepays the strike price (e.g., pays the premium plus the strike) to the Provider 561 and/or Distributor at the time of purchasing the fuel offering. When the Purchaser subsequently makes a fuel purchase 562 , there is a determination of whether the pump price is greater than the strike price 563 , and if not, the Purchaser is charged the pump price 564 . If the pump price is greater than the strike price 563 (or another threshold price as determined by the implementation), in one embodiment, the Purchaser's fuel offering(s) is(are) exercised and Purchaser's profile is updated 565 , and the Provider (and/or Distributor) pays out the pump price 566 (e.g., to the fuel retailer). In another embodiment, if the pump price is greater than the strike price 563 (or like threshold price), the Purchaser may be notified and queried to determine if they wish to exercise their offering(s) 567 with the Purchaser's response 568 determining the next action ( 564 / 565 ).
[0095] FIG. 5D provides a flow diagram for an embodiment in which the Purchaser pays the premium to the Provider 571 and/or Distributor at the time of purchasing the fuel offering. When the Purchaser subsequently makes a fuel purchase 572 , there is a determination of whether the pump price is greater than the strike price 573 , and if not, the Purchaser is charged the pump price 574 . If the pump price is greater than the strike price 573 (or another threshold price as determined by the implementation), in one embodiment, the Purchaser's fuel offering(s) is(are) exercised and Purchaser's profile is updated 575 , the Purchaser is charged the strike price 576 (e.g., pays the strike price to the fuel retailer) and the Provider (and/or Distributor) pays out the difference between the strike and the pump price 577 (e.g., to the fuel retailer). In another embodiment, if the pump price is greater than the strike price 573 (or like threshold price), the Purchaser may be notified and queried to determine if they wish to exercise their offering(s) 578 and the Purchaser's response 579 decides the next action ( 574 / 575 ).
[0096] Minimum Usage Requirement
[0097] FIG. 6 illustrates an aspect of enforcing minimum usage of fuel offerings in an embodiment of the Fuel Offering Generator. Prior to discussing FIG. 6 in detail, it is instructive to first briefly review the structure and purpose of imposing minimum fuel usage consumption. In some embodiments, a fuel offering sold to a Purchaser may include a restriction directed to the manner in which the fuel offering is exercised over the specified tenor. As one example, consider an example fuel offering with the terms below.
[0000]
Type
Quantity
Strike Price
Tenor
Premium
Diesel
30k gallons
$2.50
3 months
$0.40
[0098] The exemplary terms of the illustrative fuel offering indicate a tenor of three months, during which the Purchaser may purchase up to 30 k gallons of fuel at a strike price of $2.50. To preclude the consumption of 30 k gallons all the end, or in disproportionate amounts over the three month tenor, it is contemplated that some embodiments may impose a minimum monthly usage requirement. In this manner, more predictable exercise of fuel offerings may be achieved. Of course, in other embodiments, the restriction period may be of a longer or shorter duration (e.g., quarterly minimum usage, weekly minimum usage) in accordance with the fuel offering tenor, and may be allocated in a variable fashion.
[0099] Referring now to FIG. 6 , in one embodiment, enforcing a monthly minimum usage begins with a determination regarding whether the end of the current calendar date coincides with the end of the month 605 or some other stipulated period. The Purchaser's profile is queried to determine the monthly fixed volume (F), which represents the amount that the Purchaser must use per month 610 . The Purchaser's profile is queried a second time to retrieve the total quantity of fuel already consumed by the Purchaser for the current month, (U) 615 . A determination is then made regarding whether the total quantity of fuel already consumed in the current month (U) is greater than the fixed volume (F) 620 . If so, the process terminates because it is determined that the Purchaser has already purchased in excess of the fixed volume (F) for the current month. Otherwise, a calculation is performed to compute the difference (D) between the fixed volume (F) and the total quantity of fuel already consumed (U) 625 . A further evaluation is performed to determine the amount to be credited to the Purchaser's account for the unused portion. The further calculation determines an amount to be credited (V) corresponding to the value of (D) minus any fees (e.g., due to failure to meet fixed volume requirements), multiplied by the strike price 630 . This amount (V) may then be credited back to the Purchaser's account 635 .
[0100] For example, in one embodiment, if a Purchaser purchases a fuel offering for a quantity of 500 gallons of gasoline over a tenor of 10 months, the fuel offering may specify a minimum monthly usage of 50 gallons, i.e., F=50. In this exemplary case, if the Purchaser uses less than 50 gallons in the first month (e.g., 20 gallons), then the balance, 30 gallons (i.e., the unused portion), is deducted from the Purchaser's total available volume, leaving 450 gallons at the start of the second month. In one embodiment, in the event of a prepay, the strike price for the deducted (i.e., unused) gallons may be returned to the Purchaser, while in another embodiment the prepayed strike for the deducted gallons are not returned to the Purchaser. Alternatively, if the Purchaser uses an amount in excess of 50 in a particular month (e.g., 70 gallons), then no action is required in that the Purchaser has met his or her minimum usage requirement for the month.
[0101] Maximal Fuel Usage Restrictions
[0102] With reference now to FIG. 7 , there is shown a process for enforcing periodic (e.g., monthly) maximum fuel usage restrictions on fuel offerings. Prior to discussing process in detail, it is instructive to first briefly review the structure and purpose of monthly fuel usage restrictions. In general, a fuel offering sold to a Purchaser may include a restriction directed to the manner in which the fuel is consumed over the tenor of the offering. As one example, consider the following exemplary fuel offering—
[0000]
Type
Quantity
Strike Price
Tenor
Premium
Diesel
30k gallons
$2.50
3 months
$0.40
[0103] The exemplary illustrative offering has a tenor of three months, during which the Purchaser may consume up to 30 k gallons of fuel with a strike price of $2.50/gallon. To preclude the consumption of 30 k gallons all at once, or in grossly disproportionate amounts over the three month tenor, it is contemplated to impose a monthly cap (i.e., monthly maximum usage restriction). In this manner, more predictable consumption and/or exercising of offerings may be achieved. Of course, in other embodiments, the restriction period may be of a longer or shorter duration (e.g., quarterly cap, weekly cap) in accordance with offering tenor.
[0104] Referring again to FIG. 7 , the process for enforcing a monthly cap restriction begins with a Purchaser 220 attempting to exercise an offering on a quantity of fuel (e.g., “N” gallons) 701 . In response, the Purchaser's profile is queried to determine a cap (e.g., monthly cap) amount specified as offering parameters within an offering owned by the Purchaser. The Purchaser's profile may also be queried to retrieve a total quantity of fuel, “M”, previously consumed by the Purchaser for the current month 703 . A determination is then made as to whether the sum of the fuel already consumed “M” by the Purchaser in the current month plus the amount of fuel “N” on which the Purchaser seeks to exercise his or her offering(s) is less than or equal to the monthly cap restriction 705 . If so, the Purchaser is permitted to exercise on “N” gallons of fuel 707 . Otherwise, a determination is made of the remaining amount of fuel that may be allocated to the Purchaser to stay within the limitations of the imposed monthly cap 709 . The remaining amount which may be allocated is an amount “B”, less than the requested amount “N”, which may be determined by subtracting the amount of fuel already consumed in the month “M” from the monthly cap. The Purchaser may, in one implementation, be issued a notice indicating that the Purchaser's remaining allowable monthly allocation is “B” gallons 711 . The Purchaser may be offered the choice to proceed or not with the exercise of his or her offering on “B” gallons 713 . In the case where the Purchaser elects not to proceed with exercising the offering, the Purchaser may be charged the pump price 715 . Otherwise, in the case where the Purchaser elects to proceed, the Purchaser is permitted to exercise his or her offering on “B” gallons 717 and the Purchaser's profile is updated to reflect the exercise of the offering 719 . In an alternative embodiment, the Purchaser may be automatically charged the pump price if the exercise puts the Purchaser over the cap for the period.
[0105] In various embodiments, maximal usage restrictions may be implemented on a periodic, quasi-periodic, or non-periodic basis. For example, usage caps may be implemented and/or varied yearly, seasonally, monthly, weekly, daily, hourly, based on fiscal quarters, based on holiday travel patterns, based on expected high-traffic time periods, and/or the like. In one embodiment, the usage cap per period may be uniform over the tenor of the offerings owned by a Purchaser, such as being set to the total quantity of fuel covered by the offerings divided by the number of periods covered by the offering tenor. In another embodiment, the usage cap per period may vary from period to period.
[0106] Cap Payout Restriction
[0107] With reference now to FIG. 8 , there is shown a process for enforcing a cap payout restriction on fuel offerings in one embodiment. Prior to discussing the process in detail, it is instructive to first briefly review the structure and purpose of cap payout restrictions. In general, a fuel offering sold to a Purchaser may include a restriction directed to limiting the difference paid between the strike price and some reference price (e.g., pump price, national average price, spot price, and/or the like) in order to minimize Provider and/or Distributor exposure and/or liability. As one example, consider the following exemplary fuel offering—
[0000]
Type
Quantity
Strike Price
Tenor
Premium
Diesel
30k gallons
$2.50
3 months
$0.40
[0108] The exemplary illustrative offering has a tenor of three months, during which the Purchaser may consume up to 30 k gallons of fuel with a strike price of $2.50/gallon. To preclude the Purchaser from exercising the offering on purchases where the pump price or national average price is far in excess of the strike price, it is contemplated to impose a cap restriction on the payout. In other words, a payout cap may be established such that when the Purchaser exercises his or her offering, the amount paid cannot exceed the payout cap. In this manner, a higher degree of certainty is guaranteed regarding payouts. More particularly, the payout is assured not to exceed the payout cap. For example, if a Purchaser seeks to exercise an offering with a strike price of $2.50/gallon on fuel with a reference price of $3.50/gallon, and the payout cap is set to $0.50/gallon, the Purchaser will may only redeem $0.50/gallon rather than the $1.00/gallon he or she would receive in the absence of the payout cap. In an alternative embodiment, it is contemplated that the payout cap may be configured as a price cap, whereby any reference price exceeding the price cap on which a Purchaser seeks to exercise an offering may be replaced by the price cap for the purpose of determining payout obligations. In a non-prepay example, if a Purchaser seeks to exercise an offering with a strike price of $2.50/gallon on fuel with a reference price of $3.50/gallon, and the price cap is set to $3.00/gallon, the Purchaser will may only redeem $0.50/gallon rather than the $1.00/gallon he or she would receive in the absence of the price cap. In yet another embodiment, a payout and/or price cap may be expressed as some function of the premium and/or strike price (e.g., a percentage of the strike price).
[0109] Referring now to FIG. 8 in an implementation employing a payout cap, a Provider and/or Distributor may receive a notice of Purchaser exercise of an offering on some quantity of fuel 805 . The Purchaser's profile may be queried to seek and/or extract a specified payout cap amount, “K” 810 . A determination is made 815 as to whether such a cap exists in the Purchaser profile and, if not, then a basic payout amount is formulated 820 without consideration of a payout cap. Otherwise, the Generator queries a reference price corresponding to the offering being exercised. In one implementation, the Generator may determine whether the offering is subject to a pump-price reference price (e.g., the price of the retailer at which the fuel is purchased) or a financial structure reference price (e.g., a regional average price, a national average price, and/or the like) 825 . In the former case, the reference price, Z, may be set to the pump price 835 , and in the latter case, Z may be set to a national average price. A strike price, S, corresponding to the offering being exercised may be queried from a Purchaser profile 840 , and a determination made of the difference, D, between S and Z 845 . If that difference does not exceed the payout cap, K, then a basic payout is prepared 855 without consideration of a payout cap. Otherwise, the payout reimbursement to the Purchaser's account may be made based on the volume of fuel on which the offering is exercised subject to the payout restriction K.
[0110] In an alternative embodiment wherein a price cap is specified rather than a payout cap, the comparison at 850 would be between the price cap and the reference price, Z, and the payout amount at 860 would be based on the difference between the price cap and the strike price.
[0111] In various embodiments, price and/or payout caps may be implemented on a periodic, quasi-periodic, or non-periodic basis. For example, price and/or payout caps may be implemented and/or varied yearly, seasonally, monthly, weekly, daily, hourly, based on fiscal quarters, based on holiday travel patterns, based on expected high-traffic time periods, and/or the like. In one embodiment, price and/or payout caps per period may vary from period to period. In another embodiment, multiple different price and/or payout caps may be specified for different circumstances, including different locations, regions, SPZs, retailers, Purchasers, Distributors, Providers, times, periods of time, and/or the like.
[0112] Structural Constraint
[0113] FIG. 9 illustrates one aspect of structural constraints in an embodiment of Fuel Offering Generator. Specifically, FIG. 9 provides details for implementing and/or enforcing a structural constraint on the amount (or percentage) of gas volume that may be reimbursed upon exercising a fuel offering for a particular fuel purchase of a volume (N). In general, a fuel offering sold to a Purchaser may include a restriction directed to the amount or percentage volume of a fuel purchase considered eligible for reimbursement upon exercising the fuel offering during its tenor. As one example, consider the following exemplary fuel offering terms—
[0000]
Type
Quantity
Strike Price
Tenor
Premium
Diesel
30k gallons
$2.50
3 months
$0.40
[0114] The exemplary illustrative fuel offering has a tenor of three months, during which the Purchaser may exercise the fuel offering on up to 30 k gallons of fuel at a strike price of $2.50. To discourage the Purchaser from exercising the fuel offering at an fuel retailer that is relatively more expensive that other fuel retailers (e.g., a gas station that sells at $3.20 when most other stations sell at $3.00), some embodiments may impose a structural constraint that limits and/or specifies the amount (or percentage) of a fuel purchase on which a Purchaser may exercise the fuel offering.
[0115] As shown in FIG. 9 , enforcing a structural constraint pertaining to the amount (or percentage) of a fuel purchase that may be reimbursed upon exercising a fuel offering for a specified purchase volume of gas (N) begins with a Purchaser attempting to exercise a fuel offering on a purchase of (N) gallons of fuel 905 . In response to the Purchaser's attempt to exercise the offering on (N) gallons, the Purchaser's profile may be queried to retrieve associated structural constraint(s), defined herein as (Q) 910 . In the embodiment of FIG. 9 , this constraint defines a percentage multiplier to be applied to the purchase volume (N) to ascertain a reimbursable volume of fuel (R), as will be described. A determination is made regarding whether the query of the Purchaser's profile yields the structural constraint, that is, does the Purchaser's profile include the structural constraint, i.e., variable (Q). If not, the Purchaser may exercise the offering on (N) gallons of fuel at the basic payout rate 920 . Otherwise, a determination is made regarding the amount of fuel (R) that is considered to be reimbursable, in this case, a percentage of the total purchase amount (N) on which the Purchaser desires to exercise the offering on 925 . For some embodiments, the determination may be a computation comprising multiplication of the (N) gallons of total fuel purchase by the constraint parameter (Q) to yield a reimbursable volume of fuel (R). Reimbursement is then made to the Purchaser's account based on the volume (R) 930 , i.e., the fuel offering is exercised on (R) and not the total purchase (N). In some embodiments, the Purchaser may be notified of the restricted reimbursement 935 . Depending on the embodiment, structural constraints may be implemented on a fixed amount per purchase and/or be distributed over the tenor of a fuel offering in a periodic, quasi-periodic, or non-periodic manner.
[0116] Geography
[0117] In one embodiment, the Fuel Offering Generator may utilize single price zones (SPZs) in determining a price matrix, strike price and/or premium of a fuel offering. SPZs may define, for example, a geographic area and/or other grouping, such as certain station groups, station brands and/or the like, in which a fuel offering may be exercised (i.e., where the fuel offering Purchaser may get his or her selected amount of fuel at the single, preset price).
[0118] In one embodiment, as shown in FIG. 10 , the Fuel Offering Generator may generate an SPZ map 1005 . In certain embodiments, a fuel offering may be restricted to only one SPZ. In another embodiment, the exercise of the fuel offering may be restricted to multiple, pre-selected SPZ(s), i.e., the Purchaser selects one or more SPZs when purchasing the fuel offering, and can only exercise the fuel offering within the identified SPZ(s). In an alternative embodiment, the Purchaser may be allowed to exercise the fuel offering outside of the single or multiple pre-selected SPZ(s), but doing so may be associated with an additional fee/penalty. Based on the SPZ map (and associated price matrix data), the Fuel Offering Generator may create pricing structures and/or strike adjustments for multi-SPZ Purchasers 1010 . Alternatively, or additionally, the Fuel Offering Generator may determine fees/penalties for exercising fuel offerings outside of the pre-selected SPZ(s) 1011 . In one embodiment, the pricing structures, strike adjustments and/or fees/penalties are fixed at purchase (e.g., a Purchaser buys a fuel offering for SPZ1 and locks in an adjustment of $0.25 per gallon for SPZ2 for purchases, if any, in SPZ2). In another embodiment, the pricing structures, strike adjustments and/or fees/penalties may be floating and/or variable until the time of exercise. The Fuel Offering Generator may also manage Purchasers' utilization of SPZs 1015 , including managing Purchasers' pricing structures, strike adjustments and/or fees/penalties.
[0119] FIG. 11 provides additional detail regarding SPZ mapping and management for an embodiment of the Fuel Offering Generator. Upon receiving a request to determine SPZs 1101 , the Fuel Offering Generator may determine if the SPZs are to be set to existing geographic boundaries 1105 . If the SPZs are to be set to existing geographic boundaries 1105 , the Fuel Offering Generator determines what scale (e.g., city, county, metropolitan area, state and/or region) for setting the boundaries is appropriate 1110 . In one embodiment, the size of the SPZ may be particularly relevant in pricing associated fuel offerings, for example, the fuel offering for a large SPZ may be relatively expensive due to adverse selection and/or moral hazard issues due to a larger distribution and/or geographic area. Similarly, in one embodiment, the Fuel Offering Generator may determine SPZs to minimize excluding or “shutting out” potential Purchasers, for example, Purchasers in upstate New York may prefer a fuel offering in which geographic SPZ determination is based on county, rather than state. The Fuel Offering Generator may also account for other issues in determining SPZs, such as the smaller the SPZ, the more restrictive the fuel offering and/or the more complicated the adjustments needed to use the fuel offering products across SPZs. Based on such information, the Fuel Offering Generator may then set the boundaries of the SPZs to the appropriate existing geographic boundaries 1115 . While some embodiments may set SPZs according to one scale, other embodiments may combine scales in constructing SPZs (e.g., one SPZ's boundary may be set to a city, while another SPZ's boundary is set to a state). The Fuel Offering Generator may then determine the price matrix for each SPZ 1145 and store the price matrices in a SPZ table 1150 .
[0120] If the SPZs are not to be set to existing geographic boundaries 1105 , the Fuel Offering Generator collects 1120 and stores 1125 a geographic distribution of pricing variables. The Fuel Offering Generator may then perform a similarity analysis on the geographically distributed pricing variables 1130 and, as described previously, determine the scale or granularity with which the SPZ divisions will be set 1135 . The Fuel Offering Generator may then assign SPZs according to the similarity analysis and/or determined granularity 1140 . In a further embodiment, the assigned geographic boundaries may include, but are not limited to, existing geographic boundaries. The Fuel Offering Generator then determines the price matrix for each SPZ 1145 and stores the price matrices in an SPZ table 1150 .
[0121] FIG. 12 provides additional detail regarding the SPZ pricing aspect of an embodiment of Fuel Offering Generator. A Purchaser interacts with the Fuel Offering Generator and specifies desired terms for a fuel offering 1205 . The Purchaser then specifies one or more SPZs in which they want the ability to exercise the fuel offering 1210 . The Fuel Offering Generator then determines is the Purchaser has specified multiple SPZs 1215 , and if not, serves the fuel offering pricing based for the desired terms and selected SPZ 1220 . In one embodiment, if the Purchaser has specified multiple SPZs 1215 , the Fuel Offering Generator identifies the most expensive SPZ of the multiple SPZs based on the desired terms 1225 and derives an adjustment table (e.g., a strike adjustment table) for the other specified SPZs 1230 . In other embodiments, the Fuel Offering Generator may derive an adjustment table for a Purchaser's primary SPZ (e.g., the Purchaser's default location, most traveled location, and/or the like), with credits for exercising fuel offerings in relatively cheaper SPZs and debits or penalties for exercising in relatively more expensive SPZs. The Fuel Offering Generator may then serve the fuel offering pricing based on the most expensive selected SPZ and the derived adjustment table for the Purchaser's desired terms 1235 .
[0122] Moving momentarily back to the topic of restrictions and constraints, in some embodiments, the Fuel Offering Generator may provide fuel offerings that in which there is a withdrawal expiry, i.e., a certain amount or percentage of the initial amount (e.g., initial volume amount of the fuel offering) that must be exercised before a specified time or else be subject to expiration. For example, the specifications of a certain fuel offering may include a particular strike price, a total volume of 1200 gallons, a term of one year, and requirement that the Purchaser must exercise at least 8.33% (i.e., purchase at least 100 gallons) each month or else lose the difference. In one embodiment, the withdrawal expiry is set uniformly, for example, if the term of the fuel offering is one year, and the length of a sub-period is one month, 8.33% of the initial total of the fuel offering must be exercised by the end of each month or be subject to expiration, while in another embodiment, the withdrawal expiry could be non-uniform. FIG. 13A illustrates the available exercise volume per month for a fuel offering with a term of one year, an initial exercisable volume of 1200 gallons, and a withdrawal expiry of 8.33% (100 gallons) per month. As can be seen in the figure, the Purchaser may exercise any or all of the 1200 gallons in the first month, but only a maximum of 100 gallons by the last month.
[0123] In one implementation, the required exercise could be based on a cumulative amount, for example, in the situation described above, if a Purchaser exercised 20% in the first month and only 1% in the second month, no part of the fuel offering would be subject to expiration (i.e., 20%+1% is greater than 8.33%+8.33%). Alternatively, in another implementation, the withdrawal expiry could be periodic, so that either a certain percentage of the initial or remaining amount must be exercised each period or be subject to expiration. In one embodiment, the Purchaser may exercise the entire remaining (i.e., non-expired) amount of the fuel offering, while in another embodiment, the fuel offering may also be subject to usage caps.
[0124] FIG. 13B provides additional detail for the withdrawal expiry aspect of one embodiment of the Fuel Offering Generator. After generation of the fuel offering, the Fuel Offering Generator checks whether it is the end of the specified sub-period 1305 , and if it is not, cycles/waits 1335 and re-checks 1305 . If it is the end of the specified sub-period 1305 , the Fuel Offering Generator queries the Purchaser profile for the specified sub-period expiry volume 1310 and the Purchaser's sub-period exercise volume 1315 . If the Purchaser's sub-period exercise volume is greater than or equal to the specified sub-period expiry volume 1320 , then no part of the Purchaser's fuel offering expires and the Fuel Offering Generator waits for the end of the next period 1335 . However, if the Purchaser's sub-period exercise volume is less the specified sub-period expiry volume 1320 , then the Fuel Offering Generator determines the difference between the sub-period expiry volume and the sub-period exercise volume 1325 and expires that amount from the Purchaser's fuel offering, updates the Purchaser's profile 1330 , and waits for the end of the next sub-period 1335 . In one embodiment, if the Purchaser prepaid the strike price, the strike price for the expired amount may be returned (but not the premium). Alternatively, some embodiments do not return the prepaid strike price.
[0125] Returning to the topic of geography, FIG. 14 provides an overview of one aspect of the multi-SPZ fuel offering exercise in an embodiment of the Fuel Offering Generator. The Fuel Offering Generator receives Purchaser exercise information for a fuel offering 1405 , for example, in one implementation, via an electronic credit transaction. The Fuel Offering Generator may then determine or extract from the exercise information the location information (e.g., address of the gas station) where the Purchaser exercised the fuel offering 1410 , and matches the location to the corresponding SPZ 1415 . If the SPZ corresponding to the exercise location information is also the most expensive SPZ of the Purchaser's specified SPZs 1420 , then the transaction is completed 1425 . If the SPZ is not the most expensive SPZ of the Purchaser's specified SPZs 1420 , the Fuel Offering Generator extracts the appropriate discount from the Adjustment Table 1430 and credits the Purchaser's account 1435 . In a further embodiment, an adjustment table may also include penalties that could be charged to a Purchaser for exercising the fuel offering outside of a pre-selected SPZ (if allowed by the Fuel Offering Generator).
[0126] In one embodiment, the adjustment table is a strike adjustment table indicating the refund or rebate the Purchaser would receive if they exercised the fuel offering in one of the selected SPZs which was not the most expensive SPZ. For example, if a Purchaser selects a fuel offering with two SPZs, Manhattan and Pittsburgh, and the Manhattan SPZ is the most expensive, the Purchaser would pay for fuel offering based on the Manhattan indicated price. However, if the strike adjustment table indicated an adjustment of $0.10 for Pittsburgh, and the Purchaser exercised the fuel offering in Pittsburgh, the Purchaser may receive a corresponding credit or rebate for exercising the fuel offering in the less expensive SPZ.
[0127] Purchaser Behavior
[0128] FIGS. 15 through 18 illustrate the process flow for one aspect of Purchaser behavior management in an embodiment of the Fuel Offering Generator. As shown in FIG. 15 , the Fuel Offering Generator may collect relative pump price usage data for a Purchaser 1505 (for example, the pump price at which the Purchaser exercises one or more fuel offerings relative to the pump price at which other Purchasers with like characteristics, such as location and/or similar fuel offerings, exercise fuel offerings). Alternatively, or additionally, other Purchaser behavior data such as the relative time-from-purchase-to-exercise of fuel offerings, suboptimal exercise traits (e.g., whether the Purchaser typically exercises the fuel offering suboptimally, and if so, if said exercise is pre-optimal and/or post-optimal), and/or the like, as well as Purchaser characteristics (e.g., demographic information) may also be collected. Depending on the implementation, the above data may be collected periodically and/or continuously. In some embodiments, the collected data for multiple Purchasers may be amassed and marketing and behavior analyses performed to identify relevant trends and characteristics of Purchasers, including data regarding adverse selection (e.g., within a particular SPZ, if there is more interest in fuel offerings among Purchaser's who typically pay higher prices) and/or moral hazard information (e.g., if Purchaser's start frequenting more expensive fuel retailers after purchase of fuel offerings).
[0129] The Fuel Offering Generator may utilize the collected data to characterize a Purchaser, and the characterization may be based on the Purchaser's current information and/or aggregate information. If the characterization is based on aggregate information 1510 , the Fuel Offering Generator determines an aggregate Purchaser behavior profile 1515 , while if the characterization is based on current Purchaser information 1510 , the Fuel Offering Generator determines a current Purchaser behavior profile 1520 . Based on the Purchaser behavior profile, the Purchaser may be grouped, rated and/or otherwise identified, where such identification is used in optimizing subsequent interactions with the Purchaser. For example, as shown in the figure, in one embodiment, the Purchaser may be identified as preferred, undesirable, or indifferent 1525 . In one implementation, the grouping may reflect the relative value the Purchaser represents (e.g., profitable, unprofitable, or break-even, respectively). The identification may be stored in the Purchasers profile 1530 , and in some embodiments, the Purchaser may be notified of their associated status and/or associated incentives or penalties (as described below in FIGS. 16 , 17 and 18 ).
[0130] As shown in FIG. 16 , in one embodiment, if the Purchaser is preferred, the Fuel Offering Generator may determine if the Purchaser's length of stay (i.e., the time the Purchaser has had a relationship with the Fuel Offering Generator and/or associated entities) is greater than a certain threshold 1640 , the Fuel Offering Generator may associate a length of stay incentive package (such as discounts, rebates, and/or the like) with the Purchaser's account and/or profile 1645 . If the Purchaser's length of stay is not greater than a certain threshold 1640 , the Fuel Offering Generator may associate another style of incentive package with the Purchaser's account and/or profile 1650 . Depending on the Purchaser characteristics, rewards or incentives may be directed to retain Purchasers, encourage increased use and/or acquisition of fuel offerings, and/or otherwise encourage or modify future Purchaser behavior.
[0131] Similarly, FIG. 17 shows Purchaser incentive structures 1780 , 1785 , 1790 related to those shown in FIG. 16 ( 1640 , 1645 , 1650 , respectively), and further illustrates an embodiment in which the Fuel Offering Generator determines if the Purchaser is in a high variance zone 1770 (e.g., Purchaser could be exercising fuel offerings at relatively expensive gas stations, but is not doing so as indicated by their preferred status), and if so, associating a supplemental bonus incentive package with the Purchaser's account and/or profile 1775 (e.g., a package that reinforces/rewards positive Purchaser behavior).
[0132] Alternatively, if the Purchaser is undesirable 1525 , in one embodiment, as shown in FIG. 18 , the Fuel Offering Generator may determine if the Purchaser represents aggregate undesirability 1855 (e.g., the Purchaser has been undesirable for a significant portion of the relationship between the Purchaser with the Fuel Offering Generator and/or associated entities), and if so, may terminate the Purchaser's account and/or not provide the Purchaser with additional fuel offerings. If the Fuel Offering Generator determines the Purchaser does not have aggregate undesirability 1855 , a penalty package (or an incentive package that directs the Purchaser towards preferred behaviors) may be associated with the Purchaser's profile and/or account 1865 .
[0133] FIG. 19 illustrates the process flow for one aspect of Purchaser behavior management in one embodiment of the Fuel Offering Generator. The Fuel Offering Generator may sample an SPZ pump price distribution 1905 in order to extract therefrom one or more statistical quantities characterizing fuel retailers within the SPZ. In one implementation, the Generator samples pump prices across all retailers within an SPZ, while in another implementation the Generator samples pump prices from some representative subset of fuel retailers within the SPZ. In still another embodiment, the Generator may sample pump prices across a subset of retailers in the SPZ that excludes one or more non-participating fuel retailers from consideration. The Generator may determine a measure of pump price spread (σ) 1910 , such as a standard deviation, variance, and/or the like. A determination is made 1915 as to whether this pump price spread measure exceeds a pre-established threshold, and if not, then the process of FIG. 19 completes with no further action. Otherwise, if the pump price spread measure exceeds the threshold 1915 , then fuel retailers in the SPZ may be segmented into a plurality of price groups based on the relation of their pump prices to the average pump price 1920 . For example, fuel retailers may be segmented and/or grouped based on the number of standard deviations away from the mean pump price that their pump prices fall. In one implementation, a fuel retailer's current pump price is considered, while in another implementation the fuel retailer's pump price averaged over some period of time is considered. In some embodiments, the segmentation information may be used by the Fuel Offering Generator as an input in determining a price matrix and/or in constructing an appropriate hedging strategy. Based on this segmentation, the Generator may incentivize or penalize Purchaser solicitation of particular fuel retailers 1925 . In some embodiments, incentives and/or penalties may be provided and/or assessed immediately (i.e., communicated to Purchaser's to directly influence behavior), while in a further embodiment, such incentives and/or penalties may take the form of modified premiums, price adjustments and/or restrictions associated with subsequent fuel offerings.
[0134] FIG. 20 illustrates an aspect of fuel retailer incentivizing for some embodiments of the Fuel Offering Generator. The Fuel Offering Generator samples SPZ pump price distribution 2005 for one or more statistical quantities characterizing fuel retailers within the SPZ, in one embodiment in the process as described in FIG. 19 . The Fuel Offering Generator may determine a measure of pump price spread (σ) 2010 , such as a standard deviation, variance, and/or the like, and a determination is made 2015 as to whether this pump price spread measure exceeds a pre-established threshold, and if not, then the process of FIG. 20 completes with no further action. Otherwise, if the pump price spread measure exceeds the threshold 2015 , the Fuel Offering Generator segments fuel retailers in the SPZ into a plurality of price groups based on the relation of their pump prices to the average pump price 2020 , similar to FIG. 19 above. The Fuel Offering Generator then determines the fuel offering utilization within and/or across the price groups 2025 and identifies if, for a particular price group and/or specific fuel retailer(s) within the price group, there is minimum utilization by Purchasers 2030 (i.e., most Purchasers are not exercising their fuel offering(s)s at the fuel retailers within the price group). In some embodiments, information regarding fuel offering utilization within and/or across the price groups may be used by the Fuel Offering Generator as an input in determining a price matrix and/or in constructing an appropriate hedging strategy.
[0135] If there is not minimum utilization 2030 , in particular, if there is not minimum utilization of the more expensive fuel retailers by Purchasers, the Fuel Offering Generator does not continue the process of FIG. 20 , and in a further embodiment, the Fuel Offering Generator may reassess associated pricing, incentives, penalties, premiums, price adjustments and/or restrictions, for example, as described in FIG. 19 . If there is minimum utilization of a price group and/or particular fuel retailer(s) by Purchasers 2030 , as shown in FIG. 21 , the Fuel Offering Generator may determine the group mobility premium 2135 . In one embodiment, the group mobility premium represents the value that inclusion in another price group (and the associated increase in Purchaser solicitation) represents to the fuel retailer(s), while in another embodiment the group mobility premium represents the cost of allowing and/or not disincentivizing Purchaser solicitation of the fuel retailer(s). In yet another embodiment, the group mobility premium represents the value that Purchasers place on having access to the particular price group and/or fuel retailer(s). The group mobility premium may, in some embodiments, by utilized by the Fuel Offering Generator as an input in determining a price matrix and/or in constructing an appropriate hedging strategy. In one embodiment, the Fuel Offering Generator and/or associated entities may utilize the group mobility premium in offering or negotiating group mobility (e.g., the removal of restrictions and/or penalties to allow fuel retailers access to Purchasers) with one or more fuel retailers. This may be particular attractive to fuel retailers with relatively high pump prices (such as premium gas stations or conveniently located retailers) in that it allows for segmentation of customers and/or de facto price discrimination. For example, in one embodiment, a gas station could continue to charge a relatively high pump price to typical customers, while also gaining access to the solicitation of Purchasers. If the fuel retailer accepts the offer and associated group mobility premium 2145 , the Fuel Offering Generator adjusts the fuel retailer's position within the price groups 2150 . In one embodiment the group mobility premium could be paid by the fuel retailer to the Fuel Offering Generator (and/or associated entities) as a one time and/or periodic fee. In another embodiment, the group mobility premium could consist of and/or further include a revenue and/or risk sharing agreement, with pricing adjustment and/or payments from the fuel retailer to the Fuel Offering Generator (and/or associated entities) and/or vice versa. In yet another embodiment, said pricing adjustments and/or payments could be made from the fuel retailer and/or Fuel Offering Generator (and/or associated entities) to the Purchaser, as necessary. In some embodiments, the group mobility premium and associated arrangements may be used by the Fuel Offering Generator as an input in determining a price matrix and/or in constructing an appropriate hedging strategy.
Fuel Offering Generator System Controller
[0136] FIG. 22 of the present disclosure illustrates inventive aspects of an Fuel Offering Generator controller 2201 in a block diagram. In this embodiment, the Fuel Offering Generator controller 2201 may serve to aggregate, process, store, search, serve, identify, instruct, generate, match, and/or facilitate comparative interactions with information, and/or other related data.
[0137] Typically, users, which may be people and/or other systems, engage information technology systems (e.g., commonly computers) to facilitate information processing. In turn, computers employ processors to process information; such processors are often referred to as central processing units (CPU). A common form of processor is referred to as a microprocessor. CPUs use communicative signals to enable various operations. Such communicative signals may be stored and/or transmitted in batches as program and/or data components facilitate desired operations. These stored instruction code signals may engage the CPU circuit components to perform desired operations. A common type of program is a computer operating system, which, commonly, is executed by CPU on a computer; the operating system enables and facilitates users to access and operate computer information technology and resources. Common resources employed in information technology systems include: input and output mechanisms through which data may pass into and out of a computer; memory storage into which data may be saved; and processors by which information may be processed. Often information technology systems are used to collect data for later retrieval, analysis, and manipulation, commonly, which is facilitated through a database program. Information technology systems provide interfaces that allow users to access and operate various system components.
[0138] In one embodiment, the Fuel Offering Generator system controller 2201 may be connected to and/or communicate with entities such as, but not limited to: one or more users from user input devices 2211 ; peripheral devices 2212 ; a cryptographic processor device 2228 ; and/or a communications network 2213 .
[0139] Networks are commonly thought to comprise the interconnection and interoperation of clients, servers, and intermediary nodes in a graph topology. It should be noted that the term “server” as used throughout this disclosure refers generally to a computer, other device, program, or combination thereof that processes and responds to the requests of remote users across a communications network. Servers serve their information to requesting “clients.” The term “client” as used herein refers generally to a computer, other device, program, or combination thereof that is capable of processing and making requests and obtaining and processing any responses from servers across a communications network. A computer, other device, program, or combination thereof that facilitates, processes information and requests, and/or furthers the passage of information from a source user to a destination user is commonly referred to as a “node.” Networks are generally thought to facilitate the transfer of information from source points to destinations. A node specifically tasked with furthering the passage of information from a source to a destination is commonly called a “router.” There are many forms of networks such as Local Area Networks (LANs), Pico networks, Wide Area Networks (WANs), Wireless Networks (WLANs), etc. For example, the Internet is generally accepted as being an interconnection of a multitude of networks whereby remote clients and servers may access and interoperate with one another.
[0140] The Fuel Offering Generator system controller 2201 may be based on common computer systems that may comprise, but are not limited to, components such as: a computer systemization 2202 connected to memory 2229 .
[0141] Computer Systemization
[0142] A computer systemization 2202 may comprise a clock 2230 , central processing unit (CPU) 2203 , a read only memory (ROM) 2206 , a random access memory (RAM) 2205 , and/or an interface bus 2207 , and most frequently, although not necessarily, are all interconnected and/or communicating through a system bus 2204 . Optionally, the computer systemization may be connected to an internal power source 2286 . Optionally, a cryptographic processor 2226 may be connected to the system bus. The system clock typically has a crystal oscillator and provides a base signal. The clock is typically coupled to the system bus and various clock multipliers that will increase or decrease the base operating frequency for other components interconnected in the computer systemization. The clock and various components in a computer systemization drive signals embodying information throughout the system. Such transmission and reception of signals embodying information throughout a computer systemization may be commonly referred to as communications. These communicative signals may further be transmitted, received, and the cause of return and/or reply signal communications beyond the instant computer systemization to: communications networks, input devices, other computer systemizations, peripheral devices, and/or the like. Of course, any of the above components may be connected directly to one another, connected to the CPU, and/or organized in numerous variations employed as exemplified by various computer systems.
[0143] The CPU comprises at least one high-speed data processor adequate to execute program components for executing user and/or system-generated requests. The CPU may be a microprocessor such as AMD's Athlon, Duron and/or Opteron; IBM and/or Motorola's PowerPC; IBM's and Sony's Cell processor; Intel's Celeron, Itanium, Pentium, Xeon, and/or XScale; and/or the like processor(s). The CPU interacts with memory through signal passing through conductive conduits to execute stored signal program code according to conventional data processing techniques. Such signal passing facilitates communication within the Fuel Offering Generator system controller and beyond through various interfaces. Should processing requirements dictate a greater amount speed, parallel, mainframe and/or super-computer architectures may similarly be employed. Alternatively, should deployment requirements dictate greater portability, smaller Personal Digital Assistants (PDAs) may be employed.
[0144] Power Source
[0145] The power source 2286 may be of any standard form for powering small electronic circuit board devices such as the following power cells: alkaline, lithium hydride, lithium ion, lithium polymer, nickel cadmium, solar cells, and/or the like. Other types of AC or DC power sources may be used as well. In the case of solar cells, in one embodiment, the case provides an aperture through which the solar cell may capture photonic energy. The power cell 2286 is connected to at least one of the interconnected subsequent components of the Fuel Offering Generator system thereby providing an electric current to all subsequent components. In one example, the power source 2286 is connected to the system bus component 2204 . In an alternative embodiment, an outside power source 2286 is provided through a connection across the I/O 2208 interface. For example, a USB and/or IEEE 1394 connection carries both data and power across the connection and is therefore a suitable source of power.
[0146] Interface Adapters
[0147] Interface bus(ses) 2207 may accept, connect, and/or communicate to a number of interface adapters, conventionally although not necessarily in the form of adapter cards, such as but not limited to: input output interfaces (I/O) 2208 , storage interfaces 2209 , network interfaces 2210 , and/or the like. Optionally, cryptographic processor interfaces 2227 similarly may be connected to the interface bus. The interface bus provides for the communications of interface adapters with one another as well as with other components of the computer systemization. Interface adapters are adapted for a compatible interface bus. Interface adapters conventionally connect to the interface bus via a slot architecture. Conventional slot architectures may be employed, such as, but not limited to: Accelerated Graphics Port (AGP), Card Bus, (Extended) Industry Standard Architecture ((E)ISA), Micro Channel Architecture (MCA), NuBus, Peripheral Component Interconnect (Extended) (PCI(X)), PCI Express, Personal Computer Memory Card International Association (PCMCIA), and/or the like.
[0148] Storage interfaces 2209 may accept, communicate, and/or connect to a number of storage devices such as, but not limited to: storage devices 2214 , removable disc devices, and/or the like. Storage interfaces may employ connection protocols such as, but not limited to: (Ultra) (Serial) Advanced Technology Attachment (Packet Interface) ((Ultra) (Serial) ATA(PI)), (Enhanced) Integrated Drive Electronics ((E)IDE), Institute of Electrical and Electronics Engineers (IEEE) 1394, fiber channel, Small Computer Systems Interface (SCSI), Universal Serial Bus (USB), and/or the like.
[0149] Network interfaces 2210 may accept, communicate, and/or connect to a communications network 2213 . Through a communications network 113 , the Fuel Offering Generator system controller is accessible through remote clients 2233 b (e.g., computers with web browsers) by users 2233 a . Network interfaces may employ connection protocols such as, but not limited to: direct connect, Ethernet (thick, thin, twisted pair 10/100/1000 Base T, and/or the like), Token Ring, wireless connection such as IEEE 802.11a-x, and/or the like. A communications network may be any one and/or the combination of the following: a direct interconnection; the Internet; a Local Area Network (LAN); a Metropolitan Area Network (MAN); an Operating Missions as Nodes on the Internet (OMNI); a secured custom connection; a Wide Area Network (WAN); a wireless network (e.g., employing protocols such as, but not limited to a Wireless Application Protocol (WAP), I-mode, and/or the like); and/or the like. A network interface may be regarded as a specialized form of an input output interface. Further, multiple network interfaces 2210 may be used to engage with various communications network types 2213 . For example, multiple network interfaces may be employed to allow for the communication over broadcast, multicast, and/or unicast networks.
[0150] Input Output interfaces (I/O) 2208 may accept, communicate, and/or connect to user input devices 2211 , peripheral devices 2212 , cryptographic processor devices 2228 , and/or the like. I/O may employ connection protocols such as, but not limited to: Apple Desktop Bus (ADB); Apple Desktop Connector (ADC); audio: analog, digital, monaural, RCA, stereo, and/or the like; IEEE 1394a-b; infrared; joystick; keyboard; midi; optical; PC AT; PS/2; parallel; radio; serial; USB; video interface: BNC, coaxial, composite, digital, Digital Visual Interface (DVI), RCA, RF antennae, S-Video, VGA, and/or the like; wireless; and/or the like. A common output device is a television set 145 , which accepts signals from a video interface. Also, a video display, which typically comprises a Cathode Ray Tube (CRT) or Liquid Crystal Display (LCD) based monitor with an interface (e.g., DVI circuitry and cable) that accepts signals from a video interface, may be used. The video interface composites information generated by a computer systemization and generates video signals based on the composited information in a video memory frame. Typically, the video interface provides the composited video information through a video connection interface that accepts a video display interface (e.g., an RCA composite video connector accepting an RCA composite video cable; a DVI connector accepting a DVI display cable, etc.).
[0151] User input devices 2211 may be card readers, dongles, finger print readers, gloves, graphics tablets, joysticks, keyboards, mouse (mice), remote controls, retina readers, trackballs, trackpads, and/or the like.
[0152] Peripheral devices 2212 may be connected and/or communicate to I/O and/or other facilities of the like such as network interfaces, storage interfaces, and/or the like. Peripheral devices may be audio devices, cameras, dongles (e.g., for copy protection, ensuring secure transactions with a digital signature, and/or the like), external processors (for added functionality), goggles, microphones, monitors, network interfaces, printers, scanners, storage devices, video devices, video sources, visors, and/or the like.
[0153] It should be noted that although user input devices and peripheral devices may be employed, the Fuel Offering Generator system controller may be embodied as an embedded, dedicated, and/or monitor-less (i.e., headless) device, wherein access would be provided over a network interface connection.
[0154] Cryptographic units such as, but not limited to, microcontrollers, processors 2226 , interfaces 2227 , and/or devices 2228 may be attached, and/or communicate with the Fuel Offering Generator system controller. A MC68HC16 microcontroller, commonly manufactured by Motorola Inc., may be used for and/or within cryptographic units. Equivalent microcontrollers and/or processors may also be used. The MC68HC16 microcontroller utilizes a 16-bit multiply-and-accumulate instruction in the 16 MHz configuration and requires less than one second to perform a 512-bit RSA private key operation. Cryptographic units support the authentication of communications from interacting agents, as well as allowing for anonymous transactions. Cryptographic units may also be configured as part of CPU. Other commercially available specialized cryptographic processors include VLSI Technology's 33 MHz 6868 or Semaphore Communications' 40 MHz Roadrunner 184.
[0155] Memory
[0156] Generally, any mechanization and/or embodiment allowing a processor to affect the storage and/or retrieval of information is regarded as memory 2229 . However, memory is a fungible technology and resource, thus, any number of memory embodiments may be employed in lieu of or in concert with one another. It is to be understood that the Fuel Offering Generator system controller and/or a computer systemization may employ various forms of memory 2229 . For example, a computer systemization may be configured wherein the functionality of on-chip CPU memory (e.g., registers), RAM, ROM, and any other storage devices are provided by a paper punch tape or paper punch card mechanism; of course such an embodiment would result in an extremely slow rate of operation. In a typical configuration, memory 2229 will include ROM 2206 , RAM 2205 , and a storage device 2214 . A storage device 2214 may be any conventional computer system storage. Storage devices may include a drum; a (fixed and/or removable) magnetic disk drive; a magneto-optical drive; an optical drive (i.e., CD ROM/RAM/Recordable (R), ReWritable (RW), DVD R/RW, etc.); an array of devices (e.g., Redundant Array of Independent Disks (RAID)); and/or other devices of the like. Thus, a computer systemization generally requires and makes use of memory.
[0157] Component Collection
[0158] The memory 2229 may contain a collection of program and/or database components and/or data such as, but not limited to: operating system component(s) 2215 (operating system); information server component(s) 2216 (information server); user interface component(s) 2217 (user interface); Web browser component(s) 2218 (Web browser); database(s) 2219 ; mail server component(s) 2221 ; mail client component(s) 2222 ; cryptographic server component(s) 2220 (cryptographic server); the Fuel Offering Generator system component(s) 2235 ; and/or the like (i.e., collectively a component collection). These components may be stored and accessed from the storage devices and/or from storage devices accessible through an interface bus. Although non-conventional program components such as those in the component collection, typically, are stored in a local storage device 2214 , they may also be loaded and/or stored in memory such as: peripheral devices, RAM, remote storage facilities through a communications network, ROM, various forms of memory, and/or the like.
[0159] Operating System
[0160] The operating system component 2215 is an executable program component facilitating the operation of the Fuel Offering Generator system controller. Typically, the operating system facilitates access of I/O, network interfaces, peripheral devices, storage devices, and/or the like. The operating system may be a highly fault tolerant, scalable, and secure system such as Apple Macintosh OS X (Server), AT&T Plan 9, Be OS, Linux, Unix, and/or the like operating systems. However, more limited and/or less secure operating systems also may be employed such as Apple Macintosh OS, Microsoft DOS, Microsoft Windows 2000/2003/3.1/95/98/CE/Millenium/NT/Vista/XP (Server), Palm OS, and/or the like. An operating system may communicate to and/or with other components in a component collection, including itself, and/or the like. Most frequently, the operating system communicates with other program components, user interfaces, and/or the like. For example, the operating system may contain, communicate, generate, obtain, and/or provide program component, system, user, and/or data communications, requests, and/or responses. The operating system, once executed by the CPU, may enable the interaction with communications networks, data, I/O, peripheral devices, program components, memory, user input devices, and/or the like. The operating system may provide communications protocols that allow the Fuel Offering Generator system controller to communicate with other entities through a communications network 2213 . Various communication protocols may be used by the Fuel Offering Generator system controller as a subcarrier transport mechanism for interaction, such as, but not limited to: multicast, TCP/IP, UDP, unicast, and/or the like.
[0161] Information Server
[0162] An information server component 2216 is a stored program component that is executed by a CPU. The information server may be a conventional Internet information server such as, but not limited to Apache Software Foundation's Apache, Microsoft's Internet Information Server, and/or the. The information server may allow for the execution of program components through facilities such as Active Server Page (ASP), ActiveX, (ANSI) (Objective-) C (++), C#, Common Gateway Interface (CGI) scripts, Java, JavaScript, Practical Extraction Report Language (PERL), Python, WebObjects, and/or the like. The information server may support secure communications protocols such as, but not limited to, File Transfer Protocol (FTP); HyperText Transfer Protocol (HTTP); Secure Hypertext Transfer Protocol (HTTPS), Secure Socket Layer (SSL), and/or the like. The information server provides results in the form of Web pages to Web browsers, and allows for the manipulated generation of the Web pages through interaction with other program components. After a Domain Name System (DNS) resolution portion of an HTTP request is resolved to a particular information server, the information server resolves requests for information at specified locations on the Fuel Offering Generator system controller based on the remainder of the HTTP request. For example, a request such as http://123.124.125.126/myInformation.html might have the IP portion of the request “123.124.125.126” resolved by a DNS server to an information server at that IP address; that information server might in turn further parse the http request for the “/myInformation.html” portion of the request and resolve it to a location in memory containing the information “myInformation.html.” Additionally, other information serving protocols may be employed across various ports, e.g., FTP communications across port 21 , and/or the like. An information server may communicate to and/or with other components in a component collection, including itself, and/or facilities of the like. Most frequently, the information server communicates with the Fuel Offering Generator system database 2219 , operating systems, other program components, user interfaces, Web browsers, and/or the like.
[0163] Access to the Fuel Offering Generator system database may be achieved through a number of database bridge mechanisms such as through scripting languages as enumerated below (e.g., CGI) and through inter-application communication channels as enumerated below (e.g., CORBA, WebObjects, etc.). Any data requests through a Web browser are parsed through the bridge mechanism into appropriate grammars as required by the Fuel Offering Generator system. In one embodiment, the information server would provide a Web form accessible by a Web browser. Entries made into supplied fields in the Web form are tagged as having been entered into the particular fields, and parsed as such. The entered terms are then passed along with the field tags, which act to instruct the parser to generate queries directed to appropriate tables and/or fields. In one embodiment, the parser may generate queries in standard SQL by instantiating a search string with the proper join/select commands based on the tagged text entries, wherein the resulting command is provided over the bridge mechanism to the Fuel Offering Generator system as a query. Upon generating query results from the query, the results are passed over the bridge mechanism, and may be parsed for formatting and generation of a new results Web page by the bridge mechanism. Such a new results Web page is then provided to the information server, which may supply it to the requesting Web browser.
[0164] Also, an information server may contain, communicate, generate, obtain, and/or provide program component, system, user, and/or data communications, requests, and/or responses.
[0165] User Interface
[0166] The function of computer interfaces in some respects is similar to automobile operation interfaces. Automobile operation interface elements such as steering wheels, gearshifts, and speedometers facilitate the access, operation, and display of automobile resources, functionality, and status. Computer interaction interface elements such as check boxes, cursors, menus, scrollers, and windows (collectively and commonly referred to as widgets) similarly facilitate the access, operation, and display of data and computer hardware and operating system resources, functionality, and status. Operation interfaces are commonly called user interfaces. Graphical user interfaces (GUIs) such as the Apple Macintosh Operating System's Aqua, Microsoft's Windows XP, or Unix's X-Windows provide a baseline and means of accessing and displaying information graphically to users.
[0167] A user interface component 2217 is a stored program component that is executed by a CPU. The user interface may be a conventional graphic user interface as provided by, with, and/or atop operating systems and/or operating environments such as Apple Macintosh OS, e.g., Aqua, GNUSTEP, Microsoft Windows (NT/XP), Unix X Windows (KDE, Gnome, and/or the like), mythTV, and/or the like. The user interface may allow for the display, execution, interaction, manipulation, and/or operation of program components and/or system facilities through textual and/or graphical facilities. The user interface provides a facility through which users may affect, interact, and/or operate a computer system. A user interface may communicate to and/or with other components in a component collection, including itself, and/or facilities of the like. Most frequently, the user interface communicates with operating systems, other program components, and/or the like. The user interface may contain, communicate, generate, obtain, and/or provide program component, system, user, and/or data communications, requests, and/or responses.
[0168] Web Browser
[0169] A Web browser component 2218 is a stored program component that is executed by a CPU. The Web browser may be a conventional hypertext viewing application such as Microsoft Internet Explorer or Netscape Navigator. Secure Web browsing may be supplied with 128 bit (or greater) encryption by way of HTTPS, SSL, and/or the like. Some Web browsers allow for the execution of program components through facilities such as Java, JavaScript, ActiveX, and/or the like. Web browsers and like information access tools may be integrated into PDAs, cellular telephones, and/or other mobile devices. A Web browser may communicate to and/or with other components in a component collection, including itself, and/or facilities of the like. Most frequently, the Web browser communicates with information servers, operating systems, integrated program components (e.g., plug-ins), and/or the like; e.g., it may contain, communicate, generate, obtain, and/or provide program component, system, user, and/or data communications, requests, and/or responses. Of course, in place of a Web browser and information server, a combined application may be developed to perform similar functions of both. The combined application would similarly affect the obtaining and the provision of information to users, user agents, and/or the like from the Fuel Offering Generator system enabled nodes. The combined application may be nugatory on systems employing standard Web browsers.
[0170] Mail Server
[0171] A mail server component 2221 is a stored program component that is executed by a CPU 2203 . The mail server may be a conventional Internet mail server such as, but not limited to sendmail, Microsoft Exchange, and/or the. The mail server may allow for the execution of program components through facilities such as ASP, ActiveX, (ANSI) (Objective-) C (++), CGI scripts, Java, JavaScript, PERL, pipes, Python, WebObjects, and/or the like. The mail server may support communications protocols such as, but not limited to: Internet message access protocol (IMAP), Microsoft Exchange, post office protocol (POP3), simple mail transfer protocol (SMTP), and/or the like. The mail server can route, forward, and process incoming and outgoing mail messages that have been sent, relayed and/or otherwise traversing through and/or to the Fuel Offering Generator system.
[0172] Access to the Fuel Offering Generator system mail may be achieved through a number of APIs offered by the individual Web server components and/or the operating system.
[0173] Also, a mail server may contain, communicate, generate, obtain, and/or provide program component, system, user, and/or data communications, requests, information, and/or responses.
[0174] Mail Client
[0175] A mail client component 2222 is a stored program component that is executed by a CPU 2203 . The mail client may be a conventional mail viewing application such as Apple Mail, Microsoft Entourage, Microsoft Outlook, Microsoft Outlook Express, Mozilla Thunderbird, and/or the like. Mail clients may support a number of transfer protocols, such as: IMAP, Microsoft Exchange, POP3, SMTP, and/or the like. A mail client may communicate to and/or with other components in a component collection, including itself, and/or facilities of the like. Most frequently, the mail client communicates with mail servers, operating systems, other mail clients, and/or the like; e.g., it may contain, communicate, generate, obtain, and/or provide program component, system, user, and/or data communications, requests, information, and/or responses. Generally, the mail client provides a facility to compose and transmit electronic mail messages.
[0176] Cryptographic Server
[0177] A cryptographic server component 2220 is a stored program component that is executed by a CPU 2203 , cryptographic processor 2226 , cryptographic processor interface 2227 , cryptographic processor device 2228 , and/or the like. Cryptographic processor interfaces will allow for expedition of encryption and/or decryption requests by the cryptographic component; however, the cryptographic component, alternatively, may run on a conventional CPU. The cryptographic component allows for the encryption and/or decryption of provided data. The cryptographic component allows for both symmetric and asymmetric (e.g., Pretty Good Protection (PGP)) encryption and/or decryption. The cryptographic component may employ cryptographic techniques such as, but not limited to: digital certificates (e.g., X.509 authentication framework), digital signatures, dual signatures, enveloping, password access protection, public key management, and/or the like. The cryptographic component will facilitate numerous (encryption and/or decryption) security protocols such as, but not limited to: checksum, Data Encryption Standard (DES), Elliptical Curve Encryption (ECC), International Data Encryption Algorithm (IDEA), Message Digest 5 (MD5, which is a one way hash function), passwords, Rivest Cipher (RC5), Rijndael, RSA (which is an Internet encryption and authentication system that uses an algorithm developed in 1977 by Ron Rivest, Adi Shamir, and Leonard Adleman), Secure Hash Algorithm (SHA), Secure Socket Layer (SSL), Secure Hypertext Transfer Protocol (HTTPS), and/or the like. Employing such encryption security protocols, the Fuel Offering Generator system may encrypt all incoming and/or outgoing communications and may serve as node within a virtual private network (VPN) with a wider communications network. The cryptographic component facilitates the process of “security authorization” whereby access to a resource is inhibited by a security protocol wherein the cryptographic component effects authorized access to the secured resource. In addition, the cryptographic component may provide unique identifiers of content, e.g., employing and MD5 hash to obtain a unique signature for an digital audio file. A cryptographic component may communicate to and/or with other components in a component collection, including itself, and/or facilities of the like. The cryptographic component supports encryption schemes allowing for the secure transmission of information across a communications network to enable the Fuel Offering Generator system component to engage in secure transactions if so desired. The cryptographic component facilitates the secure accessing of resources on the Fuel Offering Generator system and facilitates the access of secured resources on remote systems; i.e., it may act as a client and/or server of secured resources. Most frequently, the cryptographic component communicates with information servers, operating systems, other program components, and/or the like. The cryptographic component may contain, communicate, generate, obtain, and/or provide program component, system, user, and/or data communications, requests, and/or responses.
[0178] The Fuel Offering Generator Database
[0179] The Fuel Offering Generator database component 2219 may be embodied in a database and its stored data. The database is a stored program component, which is executed by the CPU; the stored program component portion configuring the CPU to process the stored data. The database may be a conventional, fault tolerant, relational, scalable, secure database such as Oracle or Sybase. Relational databases are an extension of a flat file. Relational databases consist of a series of related tables. The tables are interconnected via a key field. Use of the key field allows the combination of the tables by indexing against the key field; i.e., the key fields act as dimensional pivot points for combining information from various tables. Relationships generally identify links maintained between tables by matching primary keys. Primary keys represent fields that uniquely identify the rows of a table in a relational database. More precisely, they uniquely identify rows of a table on the “one” side of a one-to-many relationship.
[0180] Alternatively, the Fuel Offering Generator database may be implemented using various standard data-structures, such as an array, hash, (linked) list, struct, structured text file (e.g., XML), table, and/or the like. Such data-structures may be stored in memory and/or in (structured) files. In another alternative, an object-oriented database may be used, such as Frontier, ObjectStore, Poet, Zope, and/or the like. Object databases can include a number of object collections that are grouped and/or linked together by common attributes; they may be related to other object collections by some common attributes. Object-oriented databases perform similarly to relational databases with the exception that objects are not just pieces of data but may have other types of functionality encapsulated within a given object. If the Fuel Offering Generator database is implemented as a data-structure, the use of the Fuel Offering Generator database 2219 may be integrated into another component such as the Fuel Offering Generator component 2235 . Also, the database may be implemented as a mix of data structures, objects, and relational structures. Databases may be consolidated and/or distributed in countless variations through standard data processing techniques. Portions of databases, e.g., tables, may be exported and/or imported and thus decentralized and/or integrated.
[0181] In one embodiment, the database component 2219 includes several tables 2219 a - i . A Purchaser table 2219 a includes fields such as, but not limited to: a user name, email address, address, profile, user_id, and/or the like. A Provider table 2219 b includes fields such as, but not limited to: a Provider name, email address, address, profile, Provider_id, and/or the like. A fuel vendor table 2219 c includes fields such as, but not limited to: a fuel vendor name, address, vendor_id, and/or the like. A Purchaser usage table 2219 d includes fields such as, but not limited to: Purchaser_id, Provider_id, Distributor_id, vendor_id, transaction_id, fuel used, date, fuel purchase price, and/or the like. A market usage table 2219 e includes fields such as, but not limited to: date, volume, fuel price, and/or the like. A market price table 2219 f includes fields such as, but not limited to: financial instrument_id, price, and/or the like. A Distributor table 2219 g includes fields such as, but not limited to: a Distributor name, email address, address, profile, Distributor_id, and/or the like. A single price zone table 2219 h includes fields such as, but not limited to: spz_id, region zipcode, region bounding (longitude, latitude), region radius, and/or the like. A variables table 2219 i includes fields such as, but not limited to: current fuel market variables, historical fuel market variables, price matrices, consumer price matrices, sensitivity data, Purchaser behavior data, and/or the like.
[0182] In one embodiment, the Fuel Offering Generator system database may interact with other database systems. For example, employing a distributed database system, queries and data access by Fuel Offering Generator system component may treat the combination of the Fuel Offering Generator system database, an integrated data security layer database as a single database entity.
[0183] In one embodiment, user programs may contain various user interface primitives, which may serve to update the Fuel Offering Generator system. Also, various accounts may require custom database tables depending upon the environments and the types of clients the Fuel Offering Generator system may need to serve. It should be noted that any unique fields may be designated as a key field throughout. In an alternative embodiment, these tables have been decentralized into their own databases and their respective database controllers (i.e., individual database controllers for each of the above tables). Employing standard data processing techniques, one may further distribute the databases over several computer systemizations and/or storage devices. Similarly, configurations of the decentralized database controllers may be varied by consolidating and/or distributing the various database components 2219 a - e . The Fuel Offering Generator system may be configured to keep track of various settings, inputs, and parameters via database controllers.
[0184] The Fuel Offering Generator system database may communicate to and/or with other components in a component collection, including itself, and/or facilities of the like. Most frequently, the Fuel Offering Generator system database communicates with the Fuel Offering Generator system component, other program components, and/or the like. The database may contain, retain, and provide information regarding other nodes and data.
[0185] The Fuel Offering Generator
[0186] The Fuel Offering Generator component 2235 is a stored program component that is executed by a CPU. The Fuel Offering Generator component affects accessing, obtaining and the provision of information, services, transactions, and/or the like across various communications networks. As such, the Fuel Offering Generator component enables one to access, calculate, engage, exchange, generate, identify, instruct, match, process, search, serve, store, and/or facilitate transactions to promote fuel offerings to customers. In one embodiment, the Fuel Offering Generator component incorporates any and/or all combinations of the aspects of the Fuel Offering Generator that were discussed in the previous figures.
[0187] The Fuel Offering Generator system component enabling access of information between nodes may be developed by employing standard development tools such as, but not limited to: (ANSI) (Objective-) C (++), Apache components, binary executables, database adapters, Java, JavaScript, mapping tools, procedural and object oriented development tools, PERL, Python, shell scripts, SQL commands, web application server extensions, WebObjects, and/or the like. In one embodiment, the Fuel Offering Generator system server employs a cryptographic server to encrypt and decrypt communications. The Fuel Offering Generator system component may communicate to and/or with other components in a component collection, including itself, and/or facilities of the like. Most frequently, the Fuel Offering Generator system component communicates with the Fuel Offering Generator system database, operating systems, other program components, and/or the like. The Fuel Offering Generator system may contain, communicate, generate, obtain, and/or provide program component, system, user, and/or data communications, requests, and/or responses.
[0188] Distributed Fuel Offering Generator system
[0189] The structure and/or operation of any of the Fuel Offering Generator system node controller components may be combined, consolidated, and/or distributed in any number of ways to facilitate development and/or deployment. Similarly, the component collection may be combined in any number of ways to facilitate deployment and/or development. To accomplish this, one may integrate the components into a common code base or in a facility that can dynamically load the components on demand in an integrated fashion.
[0190] The component collection may be consolidated and/or distributed in countless variations through standard data processing and/or development techniques. Multiple instances of any one of the program components in the program component collection may be instantiated on a single node, and/or across numerous nodes to improve performance through load-balancing and/or data-processing techniques. Furthermore, single instances may also be distributed across multiple controllers and/or storage devices; e.g., databases. All program component instances and controllers working in concert may do so through standard data processing communication techniques.
[0191] The configuration of the Fuel Offering Generator system controller will depend on the context of system deployment. Factors such as, but not limited to, the budget, capacity, location, and/or use of the underlying hardware resources may affect deployment requirements and configuration. Regardless of if the configuration results in more consolidated and/or integrated program components, results in a more distributed series of program components, and/or results in some combination between a consolidated and distributed configuration, data may be communicated, obtained, and/or provided. Instances of components consolidated into a common code base from the program component collection may communicate, obtain, and/or provide data. This may be accomplished through intra-application data processing communication techniques such as, but not limited to: data referencing (e.g., pointers), internal messaging, object instance variable communication, shared memory space, variable passing, and/or the like.
[0192] If component collection components are discrete, separate, and/or external to one another, then communicating, obtaining, and/or providing data with and/or to other component components may be accomplished through inter-application data processing communication techniques such as, but not limited to: Application Program Interfaces (API) information passage; (distributed) Component Object Model ((D)COM), (Distributed) Object Linking and Embedding ((D)OLE), and/or the like), Common Object Request Broker Architecture (CORBA), process pipes, shared files, and/or the like. Messages sent between discrete component components for inter-application communication or within memory spaces of a singular component for intra-application communication may be facilitated through the creation and parsing of a grammar. A grammar may be developed by using standard development tools such as lex, yacc, XML, and/or the like, which allow for grammar generation and parsing functionality, which in turn may form the basis of communication messages within and between components. Again, the configuration will depend upon the context of system deployment.
[0193] The entirety of this disclosure (including the Cover Page, Title, Headings, Field, Background, Summary, Brief Description of the Drawings, Detailed Description, Claims, Abstract, Figures, and otherwise) shows by way of illustration various embodiments in which the claimed inventions may be practiced. The advantages and features of the disclosure are of a representative sample of embodiments only, and are not exhaustive and/or exclusive. They are presented only to assist in understanding and teach the claimed principles. It should be understood that they are not representative of all claimed inventions. As such, certain aspects of the disclosure have not been discussed herein. That alternate embodiments may not have been presented for a specific portion of the invention or that further undescribed alternate embodiments may be available for a portion is not to be considered a disclaimer of those alternate embodiments. It will be appreciated that many of those undescribed embodiments incorporate the same principles of the invention and others are equivalent. Thus, it is to be understood that other embodiments may be utilized and functional, logical, organizational, structural and/or topological modifications may be made without departing from the scope and/or spirit of the disclosure. As such, all examples and/or embodiments are deemed to be non-limiting throughout this disclosure. Also, no inference should be drawn regarding those embodiments discussed herein relative to those not discussed herein other than it is as such for purposes of reducing space and repetition. For instance, it is to be understood that the logical and/or topological structure of any combination of any program components (a component collection), other components and/or any present feature sets as described in the figures and/or throughout are not limited to a fixed operating order and/or arrangement, but rather, any disclosed order is exemplary and all equivalents, regardless of order, are contemplated by the disclosure. Furthermore, it is to be understood that such features are not limited to serial execution, but rather, any number of threads, processes, services, servers, and/or the like that may execute asynchronously, concurrently, in parallel, simultaneously, synchronously, and/or the like are contemplated by the disclosure. As such, some of these features may be mutually contradictory, in that they cannot be simultaneously present in a single embodiment. Similarly, some features are applicable to one aspect of the invention, and inapplicable to others. In addition, the disclosure includes other inventions not presently claimed. Applicant reserves all rights in those presently unclaimed inventions including the right to claim such inventions, file additional applications, continuations, continuations in part, divisions, and/or the like thereof. As such, it should be understood that advantages, embodiments, examples, functional, features, logical, organizational, structural, topological, and/or other aspects of the disclosure are not to be considered limitations on the disclosure as defined by the claims or limitations on equivalents to the claims.
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The present disclosure is directed towards apparatuses, systems and methods to facilitate the pricing, sales and delivery of a commodity fuel to a Customer. In one embodiment, the disclosure teaches a Fuel Offer Generator that facilitates the purchase and management of fuel offerings. The Fuel Offer Generator allows Customers interested in securing fuel to obtain an offer for fuel at lock-in prices for various tenors. Fuel Customers can buy these fuel offers such that they may later exercise the fuel offers so their fuel costs are locked-in at desired levels (e.g., they may be set to strike prices). The Fuel Offer Generator also can establish a Premium Price that will be part of the fuel offer. The Fuel Offer Generator may generate hedges to counteract fuel related risks stemming from fuel offer purchases. Ultimately, a customer that purchases a fuel offering can exercise their fuel offering order at a specified price and redeem any difference between the market price for their purchased fuel and the price specified in their fuel offering order. The Fuel Offer Generator employs a geographical fuel pump location metric as well as consumer purchasing behavior to establish the pricing of fuel offerings.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a continuation patent application of International Application No. PCT/SE2005/0003000 filed 02 Mar. 2005 which is published in English pursuant to Article 21(2) of the Patent Cooperation Treaty and which claims priority to Swedish Application No. 0400603-7 filed 09 Mar. 2004. Said applications are expressly incorporated herein by reference in their entireties.
FIELD OF THE INVENTION
[0002] The present invention relates to a method and a device for distributing the brake torque between service brakes and auxiliary brakes of a vehicle when the vehicle is driven at a low speed and in a low gear.
BACKGROUND
[0003] It is known to arrange auxiliary brakes in a vehicle as a complement to the service brakes of the vehicle. Auxiliary brakes are primarily used in heavy-duty vehicles with the principal aim of saving the service brakes of the vehicle, especially when driving on long downhill slopes where there is a desire to brake to maintain fairly constant speed. The use of the auxiliary brakes allows the service brakes to be kept fresh, so that they can provide maximum braking force when the vehicle really does need to slow down quickly. The service brakes have a much more powerful braking action than the auxiliary brakes, partially owing to the fact that the service brakes are normally arranged on all the wheels of the vehicle. The auxiliary brakes normally act only on the driving wheels.
[0004] It is further known to differentiate between so-called primary and secondary auxiliary brakes in a vehicle. Primary and secondary alludes to the positioning of the auxiliary brake before or after the main gearbox of the vehicle. Examples of primary auxiliary brakes are ISG (Integrated Starter & Generator) and retarders. A retarder is usually of the hydrodynamic retarder or the electromagnetic retarder type. These are disposed between the engine and the main gearbox. A primary auxiliary brake can also be constituted by various types of engine brakes, for example compression brake, exhaust brake or the internal friction of the engine. The braking energy in a compression brake and exhaust brake is converted mainly into heat, which, in large part, is dissipated via the engine cooling system, though it should be noted that a substantial part (about 40% of the braking energy) accompanies the vehicle exhaust gases out through the exhaust system. The brake power which can be delivered by a primary auxiliary brake is dependent on the engine speed, and for this reason it is advantageous to maintain a relatively high engine speed whenever a primary auxiliary brake is used.
[0005] The internal friction of the engine can be adjusted by injecting a certain quantity of fuel into the engine, for example, so that the output torque from the engine becomes zero when no brake power is wanted. Another option for avoiding internal friction of the engine is to disengage the engine from the rest of the drive line by means of a clutch disposed between the engine and the gearbox. In the present context, drive line is meant to include the vehicle engine, as well as transmission components coupled to the engine, and continuing up to the drive wheels. Other controllable units which are coupled to the engine also contribute to the braking force from the engine; i.e., are added to the brake torque from the internal friction of the engine. Examples of such units are the cooling fan of the engine, the air conditioning unit of the vehicle, air compressors, generators and other accessory units coupled to the engine.
[0006] In the present disclosure, the term “friction torque of the engine” is used to denote brake torque that is obtained from the internal friction of the engine with connected units, but without any other auxiliary brakes being connected. The term “engine brakes” embraces compression brake, exhaust brake and the friction torque of the engine.
[0007] A secondary auxiliary brake, which is disposed somewhere after the main gearbox of the vehicle, is usually constituted by a retarder of the hydrodynamic or electromagnetic type. The brake power which can be delivered by a secondary auxiliary brake is dependent on the speed of the vehicle since the auxiliary brake is mounted on the output shaft of the gearbox and is therefore proportional to the rotation speed of the drive wheels.
[0008] 8 When a vehicle is driven on a downhill slope, the brake power of the auxiliary brake may not prove sufficient, but rather the driver may instead need to support this with the service brake in order to maintain a low and regular vehicle speed. On certain occasions, the brake power from an auxiliary brake can be cut-off without the driver expecting it, which can be disquieting for the driver.
[0009] Such a situation occurs when the vehicle is being driven on a steep downhill slope at a low speed and the vehicle is equipped with a semiautomatic gearbox; i.e., an automatically shifted stage-geared gearbox. These gearboxes are often non-synchronized and the vehicle has no manual clutch pedal for disconnecting the clutch in the transmission. When the driver brakes the vehicle to reduce the speed, the engine speed will also decrease. When the engine speed approaches the idling speed of the engine, the system will disengage the gearbox; i.e., the power transmission between the engine and the transmission is broken. This disengagement is realized to prevent the vehicle from driving the vehicle forward with the aid of the idle regulator and prevent the engine from being throttled down. This means, at the same time, that the brake torque deriving from the internal friction of the engine, and any primary auxiliary brakes, disappears. The result is a sudden reduction in braking torque which can cause the vehicle to start to accelerate. This can be disquieting for the driver because he senses a reduced brake power even though he is stepping on the service brake.
[0010] There is therefore a need to be able to distribute the brake torque between service brakes and engine brakes in a vehicle in a way which compensates for the loss of brake power from the engine brakes. This is the main aim of the invention which is described below.
SUMMARY
[0011] One object of the invention is therefore to provide a method and a device for distributing the brake torque between service brakes and engine brakes in a vehicle when the brake torque from the engine brake disappears.
[0012] With a method for distributing brake torque between at least one first and one second brake device on a motor vehicle comprising at least two wheel pairs, an internal combustion engine and a transmission, in which the first brake device is a friction brake which acts on at least one wheel pair and in which the second brake device acts on at least one driven wheel pair via the transmission and is disposed before the clutch device of the transmission, the object is achieved by the brake torque distribution between the first and the second brake device compensating for the loss of brake torque which occurs when the second brake device is cut off with the clutch device of the transmission.
[0013] The device according to the invention achieves the objective by distributing the brake torque between service brakes and auxiliary brakes of a motor vehicle so that it compensates for the loss of brake torque which occurs when the second brake device is cut off with the clutch device of the transmission.
[0014] By the method according to the invention, the brake torque is automatically redistributed from an engine brake to the service brakes when the transmission cuts off the engine brake. The advantage with this method is that the total brake performance of the vehicle remains constant, even when the engine brake is cut off.
[0015] In a first embodiment of the method according to the invention, the method is performed when the speed of the vehicle is low, for example when it falls below 20 km/h. The purpose of this is to secure an adequate safety level when the method is performed. In a second embodiment of the method according to the invention, the method is performed when a high gear ratio is used, for example when the total gear ratio of the gearbox exceeds, for example, 6 times. The purpose of this is to secure an adequate safety level when the method is performed.
[0016] In a third embodiment of the method according to the invention, the method is performed when the engine speed falls below a predetermined speed, for example 800 rpm. The purpose of this is to secure an adequate safety level when the method is executed.
[0017] In a fourth embodiment of the method according to the invention, the method selects particular gears on the vehicle. The advantage with this is to optimize the brake power of the auxiliary brakes. The purpose of this is to secure an adequate safety level when the method is executed.
[0018] In a fifth embodiment of the method according to the invention, the friction brakes of a trailer are also used to compensate for the loss of brake torque which occurs when the second brake device is cut off with the clutch device of the transmission. The advantage is an increase in available brake torque.
[0019] In a sixth embodiment of the method according to the invention, the method predicts the brake torque requirement through the use of, for example, an electronic map and/or GPS. The purpose of this is to increase the safety level when the method is executed.
[0020] Through the device according to the invention, the device compensates for the loss of brake torque which occurs when the second brake device is cut off with the clutch device of the transmission. The advantage with this device is that the brake torque of the vehicle is kept constant, even when the brake torque of the engine disappears.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] The invention will be described in greater detail below with reference to illustrative embodiments shown in the accompanying drawings, wherein:
[0022] FIG. 1 schematically shows a vehicle having brake devices configured according to the teachings of the disclosed invention(s).
DETAILED DESCRIPTION
[0023] The following described illustrative embodiments of the invention, with further developments and variations, should be regarded purely as examples and should in no way be considered to limit the protective scope of the patent claims. In the illustrative embodiments which are described here, disk brakes are used as examples of service brakes. The illustrative embodiments also apply to drum brakes. Furthermore, the term “wheel axle” is used not only for a physical through shaft, but also applies to wheels positioned on a geometric axis, even if the wheels are individually suspended.
[0024] FIG. 1 shows a diagrammatic representation of a vehicle 1 having a front wheel axle 2 , a first rear wheel axle 3 and a second rear wheel axle 4 . Mounted on the front wheel axle 2 is a front wheel pair 5 , which steers the vehicle. A first rear wheel pair 6 is mounted on the first rear wheel axle 3 , which is also the drive axle of the vehicle. The first rear wheel pair 6 , as shown, consists of a so-called twin assembly; i.e., two wheels on each side of the drive axle. The second rear wheel pair 7 is mounted on the second rear wheel axle 4 , which is a lifting axle which is used with heavy load. Each wheel consists of a tire fitted on a rim.
[0025] Each side of a wheel axle is equipped with a service brake 13 , here in the form of pneumatically operated disk brakes. The service brakes are electronically controlled with the aid of an electronic control unit (ECU), comprising, inter alia, a computer (not shown). The service brakes can be individually controlled, for example to allow active stabilization control (ESP=Electronic Stability Program). The vehicle further comprises a radiator 8 , an engine 9 , a gearbox 10 , a hydraulic auxiliary brake in the form of a retarder (CR=Compact Retarder) 11 and an end gear 1 2 . The engine comprises auxiliary brakes in the form of a compression brake (VCB=Volvo Compression Brake), an exhaust brake and the friction brake torque of the engine. These components are well known to persons skilled in these arts and are not described in any further detail for that reason.
[0026] Normally, a driver tries to make as much use as possible of the auxiliary brakes, especially during lengthy downhill gradients. A common driving strategy is to use the auxiliary brakes to maintain a regular vehicle speed and only to use the service brakes to reach this speed.
[0027] In a driving situation, the vehicle is driven on a downhill slope at a low speed. The driver reduces the speed still further by braking with the service brake, for example when the vehicle approaches a bend or is set to stop. When the speed is reduced without downward gearshift, then the engine speed will simultaneously decrease. When the engine speed decreases, the brake torque delivered from the compression brake and the exhaust brake decreases. When the engine speed begins to approach the idling speed of the engine, the greatest part of the engine brake comes from the internal friction of the engine. If the driver brakes still more, the engine speed will become equal to the idling speed. When this occurs, the idle regulator will adjust the engine speed to the idling speed, the effect of which is that the vehicle will continue to be driven forward unless the driver disengages. If the driver steps heavily on the brake, it is possible for the engine to be fully throttled down and to stop; i.e. kill the engine.
[0028] Since the vehicle is being driven at low speed and low engine speed, this means that a low gear is engaged. A low gear has a high gear ratio, which means that even if the friction torque of the engine is relatively low, this will be multiplied with the gear ratio of the gearbox. The internal friction in the engine can amount, for example, to about 5% of the torque which can be delivered by the engine. For low gears, a gearbox has a transmission ratio in the region of around 10 times. The effect of this is that the total braking torque from the internal friction of the engine, for example, can range from 500 to 2000 Nm in a low gear.
[0029] When a vehicle is equipped with a semiautomatic gearbox; i.e., an automatically shifted stage-geared gearbox, then the control program of the gearbox will prevent the engine speed from falling as low as the idling speed. These gearboxes are often non-synchronized and the vehicle has no manual clutch pedal for disconnecting the clutch in the transmission. The control program is therefore configured so that the gearbox disengages at an engine speed which is somewhat higher than the idling speed. For example, the idling engine speed for a truck may be 600 rpm and the disengagement engine speed may be 650 rpm.
[0030] The effect of this is that when a driver drives a vehicle at low speed and brakes in order to reduce the speed still further, the vehicle, instead of reducing the speed, can proceed to increase the speed since the gearbox disengages the engine at the predefined disengagement engine speed so that the whole of the brake power from the engine brake suddenly disappears.
[0031] With the method according to the invention for distributing brake torque between a first and a second brake device, this problem is solved.
[0032] When a driver drives a vehicle at low speed and brakes in order to reduce the speed still further, then a control unit detects the engine speed. When the engine speed begins to approach the disengagement engine speed, then the system switches to a standby mode. In the standby mode, the control unit calculates the brake torque delivered by the internal friction of the engine. If the engine speed reaches the disengagement speed, then the clutch is disengaged. At the same time, the system sends a message to the control unit of the service brakes with a request for the brake torque of the service brakes to be increased by the instantaneous brake torque of the engine brake; i.e., the brake torque exhibited by the engine brake when the request is sent.
[0033] The brake torque which is generated by the internal friction of the engine can be calculated in a variety of ways. For example, a predetermined function of engine speed and oil temperature can be used. Load from auxiliary units driven by the engine can also be taken into account. The friction torque can also be measured with the aid of a torque transducer, for example placed on the input shaft of the gearbox.
[0034] Once the control unit controlling the service brakes has received a request to increase the brake torque of the service brakes, the control unit executes the request. Advantageously, this execution; i.e., the increasing of brake torque of the service brakes, is realized with a time constant corresponding to the disengagement of the gearbox. The effect of this is that the brake torque of the service brakes increases commensurate with the decrease in brake torque of the engine brake so that the total brake torque of the vehicle remains constant. The result is that the driver does not perceive a change in the total brake torque, but rather the vehicle behaves as the driver expects. The total brake torque exerted by the service brakes now consists of the brake torque requested by the driver via the brake pedal, added to the brake torque corresponding to the brake torque of the engine brake.
[0035] If the driver releases the brake, then the brake torque requested by the driver via the brake pedal decreases. The brake torque corresponding to the brake torque of the engine brake will persist, even when the brake pedal is fully released. The request to increase the brake torque of the service brake only ceases once the clutch is reengaged.
[0036] Since the engine is disengaged, the engine speed will not increase if the vehicle speed increases. Instead, the rotation speed at the output shaft of the freewheel clutch is measured; i.e., that side of the freewheel clutch which is connected to the transmission. Once this rotation speed reaches a speed which is somewhat higher than the disengagement speed, for example 750 rpm, the clutch is reengaged and hence the brake torque of the engine is reconnected. This rotation speed is referred to as the engagement engine speed. The engagement engine speed is higher than the disengagement engine speed in order to avoid self-oscillations in the system.
[0037] In an embodiment of the method according to the invention, the service brakes in a trailer coupled to the towing vehicle can also be used to compensate for the loss of brake torque from the engine brake when the transmission is disengaged. This is advantageous, inter alia, for securing an increase in the total available brake torque, which means that there is less load placed upon the service brakes of the vehicle. Requested brake torque can be transmitted to the trailer in a variety of ways. Either the trailer can be equipped with an intelligent control unit for the brakes, which communicates with the control system of the towing vehicle. Or, alternatively, the trailer is braked with a certain intensity and the control unit of the towing vehicle constantly calculates the brake torque which this yields in order to be able to accurately control the brake torque.
[0038] In these illustrative embodiments, a calculation model is used to optimize the brake torque distribution. This calculation model has, inter alia, the instantaneous road gradient as an input parameter.
[0039] In a first illustrative embodiment of the device according to the invention, the device comprises an electronic control unit (not shown), which transmits control signals to the brake devices. The control unit detects the engine speed and calculates the brake torque delivered by the engine brake; i.e., the internal friction of the engine, when the vehicle is driven at low speed. When the engine speed reaches the disengagement engine speed, the clutch is disengaged. At the same time, the control unit sends a message to the control unit of the service brakes with a request for the brake torque of the service brakes to be increased by the instantaneous brake torque of the engine brake; i.e., the brake torque exhibited by the engine brake when the gearbox is disengaged.
[0040] Once the control unit controlling the service brakes has received a request to increase the brake torque of the service brakes, the control unit executes the request. Advantageously, this execution; i.e., the increasing of brake torque of the service brakes, is performed with a time constant corresponding to the disengagement of the gearbox. The effect of this is that the brake torque of the service brakes increases commensurate with the decrease in brake torque of the engine brake, so that the total brake torque of the vehicle remains constant. The result is that the driver does not perceive a change in the total brake torque, but rather the vehicle behaves as the driver expects. The total brake torque exerted by the service brakes now consists of the brake torque requested by the driver via the brake pedal, added to the brake torque corresponding to the brake torque of the engine brake.
[0041] Once the clutch is reengaged; i.e., once the transmission is reengaged and the internal friction of the engine is hence able to brake the vehicle, a message is sent to the control unit of the service brakes with a request to remove the brake torque which was previously added to the brake torque of the service brakes.
[0042] The brake torque which is generated by the internal friction of the engine can be calculated in a variety of ways. For example, a predetermined function of engine speed and oil temperature can be used. Load from auxiliary units driven by the engine can also be taken into account. The friction torque can also be measured with the aid of a torque transducer, for example placed on the input shaft of the gearbox.
[0043] For this brake torque calculation, the control unit can use various input signals from the vehicle. Depending on the algorithm, one or more of the following input parameters can also be used. These can be one or more of the following: vehicle speed, vehicle acceleration, instantaneous brake torque, vehicle weight, carriageway gradient, coolant temperature, outside temperature, vehicle position. In the case of a vehicle combination consisting of a towing vehicle and a trailer, those parameters which are specific to the trailer can also be used in the calculation algorithm.
[0044] The invention should not be deemed to be limited to the illustrative embodiments described above, but rather a number of further variants and modifications are conceivable within the scope of the patent claims. For example, it is possible also to distribute the brake torque between a tow vehicle and a trailer by taking into account the temperature of the brake devices of the trailer. This can be advantageous, for example, when the towing vehicle and the trailer have different brake linings.
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Method and apparatus for distributing brake torque between at least one first and one second brake device on a motor vehicle including at least two wheel pairs. The first brake device is a friction brake which acts on at least one wheel pair and the second brake device acts on at least the driven wheel pair via the transmission and is disposed before the clutch device of the transmission. Brake torque is distributed between the first and the second brake device in a manner that compensates for the loss of brake torque which occurs when the second brake device is disengaged by the clutch device of the transmission.
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BACKGROUND OF INVENTION
1. Field of Invention
This invention is related to a process for the preparation of "squaric acid" (dihydroxycyclobutenedione), the compound having the formula: ##STR1## together with the preparation of its complexes and salts. More particularly, the present invention is related to the preparation of these compounds through the reductive electrolytic cyclotetramerization of carbon monoxide in anhydrous aliphatic nitrile solvent media. The resultant compounds potentially are useful as intermediates in the preparation of dyes, polymers, virucides, and as sequestering agents.
2. Description of the Prior Art
Squaric acid (I) was first reported synthesized in 1959 by S. Cohen, J. R. Latcher and J. D. Park, J. Am. Chem. Soc., Vol. 81, p. 3480, through the hydrolysis of certain halogenated cyclobutene derivatives. Squaric acid displays a particularly interesting chemistry partially due to its dianion (II): ##STR2## which may be considered a tetrameric dianion of carbon monoxide, and which has a completely delocalized electronic structure. Consequently, although "phenolic" in nature, the acid is strong (pK 1 =0.6; pK 2 =3.4).
In U.S. Pat. No. 3,833,489 ('74) a process for preparing squaric acid, its complexes and its salts is described, together with a short summary of the state of the art at that time. The method involves passing an electric current through a solution of carbon monoxide in a solvent media selected from the group consisting of amides of phosphoric acid, amides of carboxylic aliphatic acids having from 1 to 10 carbon atoms, aliphatic ethers, cyclic ethers, liquid polyethers and anhydrous ammonia, at a temperature of from about -30° C. to a temperature up to the boiling point of said solvent and at pressures up to about 420 atm, in order to thereby cause the electrolytic cathodic reductive cyclotetramerization of the carbon monoxide; the reaction being carried out under conditions of substantial separation or non-interference of the anodic reactions and reaction products from the cathodic reactions and reaction products. Although the patentees attempted to claim as their operative group of solvent compounds all non-aqueous solvents that will conduct current with a minimum of resistance, their actual work has disclosed that only certain amides, ethers, and ammonia are operative, and that many other classes of compounds are ineffective. Furthermore, their system is severely hampered by the fact that subsequent separation of the squaric product from the reaction system is quite difficult, and thus commercial usage of this system is flawed. Other articles by the same researchers (Gazetta Chimica Italiana, Vol. 102, pp. 818-821 ('72) and Electrochimica Acta, Vol. 23, pp. 413-417, ('78)) have also investigated the influence that specific parameters such as the particular solvent, electrolyte, electrode material, carbon monoxide pressure and reaction temperature have on the yield of squaric acid. They determined that there is a great deal of unpredictability involved in this process, particularly in the properties of the particular solvent employed. Of particular interest was their finding that solvents such as acetonitrile gave poor results (about 2% current efficiency) thus leading to their conclusion that nitriles are ineffective as solvents for the production of squaric based compounds. An additional troublesome problem, particularly in a large scale commercial operation, is that the separation of the squaric acid products from the resulting residue is extremely complicated and difficult when solvents such as DMF are employed. In addition, it has been discovered that when using the preferred class of solvents claimed by U.S. Pat. No. 3,833,489 to produce squaric acid, surprisingly large fluctuations in product yields can result even in the case of substantially identical back to back experiments.
It is therefore an object of this invention to develop a simple, effective and economical process for the preparation of squaric acid, its metal complexes and its salts, by the electrochemical reductive cyclotetramerization of carbon monoxide in anhydrous aliphatic nitrile solvents producing consistently high product yields and relatively simple product isolation and extraction.
It is another object of this invention to provide a process for the preparation and recovery of squaric compounds which makes subsequent product recovery much easier and reutilization of unconsumed starting materials feasible.
SUMMARY
Accordingly, the invention involves an improved method for the preparation and recovery of squaric acid, its complexes and its salts, through the passing of an electrical current, e.g., preferably a direct current, although alternating current is operable, through a solution of carbon monoxide maintained within a temperature range spanning the liquid range of the particular solvent, and within a pressure range of about 1-420 atmospheres, and preferably about 30-150 atmospheres, to effect the electrolytic cathodic reductive cyclotetramerization of the carbon monoxide; the improvement comprising undertaking the reaction in a class of anhydrous aliphatic nitrile solvents, each containing from 2 to about 8 carbon atoms, and most preferably, isobutyronitrile. The electrical current causes the reduction of carbon monoxide to the C 4 O 4 2- squarate ion, the reaction being carried out under process conditions of substantial separation of the anodic reactions or reaction products from, or non-interference of the anodic reactions or reaction products with, the cathodic reactions or reaction products. Upon completion, solids containing substantially all of the squarate formed are isolated by centrifugation or filtration. Recovery of squaric acid, the electrolyte and other raw starting materials is thereby achieved much more easily and efficiently than in earlier systems.
DETAILED DESCRIPTION OF THE INVENTION
The electrochemical cyclotetramerization of carbon monoxide to the squarate ion has been regarded with considerable interest, as the reaction leads from a widely available and inexpensive starting material to an end product C 4 molecule which is a potentially useful monomer for certain polyamide type polymers.
However, to date there is still not available a useful commercial process for the volume production of squaric compounds, as is evidenced by its current price of about $1,000/lb. In U.S. Pat. No. 3,833,489 as well as the process of the present invention, the following reaction scheme is apparently used to form squaric acid, most often in the form of an insoluble or unreactive metal squarate salt or complex, using a dissolving metal anode as the source of cations, M: ##STR3## As in the patented process this process involves first creating an operational environment which substantially avoids oxidation in the anodic zone of the reaction products of carbon monoxide, as well as reduction in the cathodic zone of those products obtained from the anodic reaction section. Thus certain operational parameters must be established in order to prevent the products of anodic reaction and/or the anodic reaction itself from substantially interfering with the products of the cathodic reaction or with the cathodic reaction itself, and vice versa. Such non-interference can be achieved by selecting from a variety of several different conventional methods, some of which are described in U.S. Pat. No. 3,833,489, those cited herein being set forth as simply illustrative. For instance, the use of baffles, diaphragms, or the forced circulation of the solution inside the cell, by the careful selection of conditions so as to yield only the formation of chemically inert oxidation products, or by the formation of anodic oxidation products which are then continuously removed from the anolite, are operable. Of course, combinations of these techniques may also be possible.
Although the reductive electrochemical cyclotetramerization of CO to the squarate anion can be achieved to some degree under a wide variety of operational conditions, e.g. differing corrosion resistances of the anode (corrodible or noncorrodible), the use of direct or alternating current, different temperature and pressure conditions, and the differing composition of the chemical solvent, this invention is primarily concerned with the surprising improvement attained by the use of a particular class of solvents in the system described in U.S. Pat. No. 3,833,489 and in related publications. It has been found that, contrary to the teachings of these references, aliphatic nitriles containing between 2 and about 8 carbon atoms can be used to give particularly effective results as solvents in the aforementioned reaction. In particular, it has been discovered that squaric acid is generated in an insoluble form, probably as a metal salt, when carbon monoxide is electrochemically reduced in anhydrous nitrile solvent medium with corroding metal anodes; the preferred nitrile solvent being selected from the group consisting of isobutyronitrile, n-butyronitrile, propionitrile and acetonitrile. Best results are obtained when substantially anhydrous isobutyronitrile is used, and current efficiencies of about 50% have been attained. Although other aliphatic nitriles may be operative, economic considerations probably make their usage unlikely, and aromatic nitriles do not appear to be nearly as effective. Current efficiencies have been attained in the formation of squaric acid in acetonitrile that are 300% higher than previously reported. Furthermore, nitrile solvents are particularly useful since the squarate product formed, which is produced substantially in the solid state by the method of this invention, is much more readily and easily separated by centrifugation, filtration or other separation techniques than are those formed in, for example, amide medium. Additionally, the improved separation properties of the resultant product mixture make it possible to recycle the starting raw materials, such as the electrolyte, and thus could conceivably make a continuous, as well as a batch process, operable. In contrast, the product formed in the system reported by the Italians has been found to be far more difficult to separate. To date no simple, clean separation of squarate from DMF, except through the distillation of the solvent, has been attained, and this method leaves behind all non-volatiles.
Although the process described herein can be used with either a corrodible or noncorrodible anode, following the teachings of U.S. Pat. No. 3,833,489, in the preferred embodiment it is desired to operate using a corrodible anode primarily for ease in process engineering simplicity. It has been found that, depending upon the choice of solvent used, the particular anode metal chosen can be critical for effective operation. For example, squaric acid has been formed with current efficiencies of 40 to 50% when using magnesium or aluminum anodes, yet barely at all when using titanium, and not at all with soft steel. Although it is not desired to be bound by theory, this may be due to the differences in the solubility of the metal squarate salts formed in each solvent. This is because an insoluble salt prevents anodic oxidation of squarate formed at the cathode. Alternatively, these results may be due to the differences in the oxidation potentials of these anode metals in the chosen nitrile solvent, since the metal must oxidize more readily than any soluble squarate salt will oxidize, in order to prevent the anodic oxidation of squarate. Although the precise mechanism is uncertain, it is believed that the conditions existing at the anode are probably due to some combination of at least one of these factors. Anodes particularly suitable for use as corroding metal anodes in aliphatic nitrile solvents are aluminum, magnesium and tin, as well as alloys and/or mixtures thereof, and particularly aluminum and magnesium, whereas titanium and iron have been found not to be effective. Other metals may also be effective and are within the scope of this invention, such as copper, lead, zinc, indium and the like.
In contrast, the cathode material has been found to only slightly effect the electrolytical reaction. Suitable cathodes can be formed from steel and aluminum alloys and/or mixtures thereof, with steel being particularly useful. However, in the broadest embodiment, almost any material can be operable as the cathode.
In order to enhance the conductivity of the solution there may be added thereto one or more auxiliary electrolytes, such as a tetraalkylammonium halide and other electrolytes described as useful in U.S. Pat. No. 3,833,489. Tetraalkylammonium halides are most effective.
The current density employed in the electrolysis reaction can vary over a wide range depending upon the particular system parameters employed. The electrical current used can be either direct or alternating current, with the direct being preferred.
The temperature of the reaction system can range over the complete liquid range of the particular solvent employed, e.g., from the temperature just above the freezing point up to the temperature at the boiling point of the particular nitrile solvent present, with a temperature range of about 10°-50° C. particularly preferred, and the system can be operated at pressures ranging from substantially atmospheric up to about 420 atmospheres, with pressures of between about 30-150 atmospheres being particularly preferred although, within certain limits, the higher the pressure, the better the conversion attained. A particularly interesting aspect of the invention is the surprising unpredictability of the effectiveness of a particular solvent. It was discovered that a significant number of the claimed solvents of U.S. Pat. No. 3,833,489 are substantially inoperative, together with several common polar electrochemical solvents, such as propylene carbonate and sulfolane.
The following examples are provided to illustrate the invention in accordance with the principles of this invention but are not construed as limiting the invention in any way except as indicated by the appended claims.
EXAMPLES
In the following examples, the precise amount of squaric acid present was determined by HPLC-UV techniques using an Aminex HPX87 column (Bio Rad Laboratories) with a 0.001N H 2 SO 4 mobile phase (flow rate=0.6 ml/min). The column temperature was maintained at 65° C. Squaric acid was detected spectrophotometrically at 270 nm. Retention time was approximately 6 to 7 minutes. The apparatus described in example 1 is also used for examples 2, 3, 4 and 9-14.
EXAMPLE 1
This example illustrates the coupling of CO to squaric acid in isobutyronitrile solvent with a Bu 4 NBr electrolyte and an aluminum anode at 1000 psig CO.
Isobutyronitrile (60 ml) and Bu 4 NBr (3.0 g) were charged to a 200 ml Paar bomb equipped with a magnetic stirring vane. An aluminum rod was connected via a bulkhead electrical adapter to the positive pole of a power supply. The bomb was sealed, connected to the negative pole of the power supply, and pressurized with CO to 1000 psig. Direct current (approximately 100 mA) was applied until 18.6 mF charge had passed. The gas was vented and the resultant solids were separated from the electrolysis mixture by centrifugation, washed with isobutyronitrile, and dried (2.81 g). Analysis of the solids showed that they contained 12.82 wt. % squaric acid (0.36 g, 34% current efficiency).
EXAMPLE 2
This example illustrates the coupling of CO to squaric acid in isobutyronitrile with a Bu 4 NI electrolyte.
Isobutyronitrile (60 mL) and Bu 4 NI (4.0 g) were stirred under 1000 psig CO and direct current (approximately 100 mA) was applied until 24.8 mF of charge had passed. The gas was vented and the resultant solids were separated from the electrolysis mixture by filtration, washed with isobutyronitrile, and dried (2.69 g). Analysis of these solids showed that they contained 22.04 wt. % squaric acid (0.59 g, 42% current efficiency).
EXAMPLE 3
This example illustrates the coupling of CO to squaric acid in a specially dried isobutyronitrile-Bu 4 NI solution.
Bu 4 NI (5.0 g) was dissolved in isobutyronitrile (100 mL) and this solution was stored over activated 4A sieves for 4 days in a darkened room. The dried electrolyte solution (60 mL) was then stirred under 1000 psig CO and a direct current (approximately 100 mA) was passed until 24.0 mF of charge had passed. The gas was vented and the resultant solids were separated by filtration and air dried (2.59 g). Analysis of these solids showed that they contained 23.8 wt. % squaric acid (0.62 g; 45% current efficiency).
EXAMPLE 4
This example illustrates the coupling of CO to squaric acid in wet isobutyronitrile with Bu 4 NBr.
Isobutyronitrile (60 mL), distilled H 2 O (0.5 mL), and Bu 4 NBr (3.0 g) were stirred under 1000 psig CO and direct current (approximately 100 mA) was passed until 15.9 mF charge had passed. The gas was then vented and the electrolysis mixture was analyzed for squaric acid (0.005 wt. %, 0.002 g, 0.2% current efficiency).
EXAMPLE 5
This example illustrates the coupling of CO to squaric acid using a magnesium anode.
The same apparatus was used as in Example 1, except that a magnesium rod was used as an anode, rather than an aluminum one. Isobutyronitrile (60 mL) and Bu 4 NBr (3.0 g) were stirred under 1000 psig CO and direct current (approximately 100 mA) was applied until 26.0 mF charge had passed. The gas was vented and the resultant solids were separated from the electrolysis mixture by centrifugation, washed with isobutyronitrile, and dried (3.53 g). Analysis of these solids showed that they contained 11.48 wt. % squaric acid (0.41 g, 27% current efficiency).
EXAMPLE 6
This example illustrates the coupling of CO to squaric acid using Bu 4 NI electrolyte with a magnesium anode at 1400 psig CO.
The same apparatus was used as in Example 1, with the substitution of a magnesium rod as an anode, in place of an aluminum one. Isobutyronitrile (60 mL, distilled and dried over activated 4A sieves) and Bu 4 NI (2.0 g) were stirred under 1400 psig CO and a direct current (approximately 100 mA) was applied until 27.2 mF of charge had passed. The gas was vented and the resultant solids were separated from the electrolysis mixture by filtration and dried under an air stream (2.36 g). Analysis of these solids showed that they contained 27.54 wt. % squaric acid (0.65 g, 42% current efficiency). The filtered electrolyte solution contained no squarate and was next used, without further handling, in Example 7.
EXAMPLE 7
This example illustrates the coupling of CO to squaric acid in a previously used electrolyte solution.
The same apparatus was used as in Example 6. The filtered electrolyte solution used in example 6 was stirred under 1400 psig CO and a direct current (approximately 100 mA) was applied until 22.2 mF of charge had passed. The gas was vented and the resultant solids were separated from the electrolysis mixture by filtration and dried under an air stream (2.46 g). Analysis of these solids showed that they contained 25.82 wt. % squaric acid (0.63 g, 50% current efficiency). The filtered electrolyte solution contained no squarate.
EXAMPLE 8
This example illustrates the coupling of CO to squaric acid using a titanium anode.
The same apparatus was used as in Example 1, with a substitution of a titanium rod as an anode, rather than an aluminum one. Isobutyronitrile (60 mL) and Bu 4 NBr (3.0 g) were stirred under a 1000 psig CO and direct current (approximately 100 mA) was applied for 6 h. The gas was vented and the electrolysis mixture was then analyzed for squaric acid (0.016 wt. %, 0.0081 g).
EXAMPLE 9
This example illustrates the coupling of CO to squaric acid in propionitrile solvent.
Propionitrile (60 mL) and Bu 4 NBr (3.0 g) were stirred under 1000 psig CO and a direct current (100 mA, initially) was applied until 35.0 mF charge had passed. The gas was vented and the resultant solids were separated from the electrolysis mixture by centrifugation, washed with propionitrile, and dried (3.86 g). Analysis of these solids showed that they contained 8.36 wt. % squaric acid (0.32 g, 16% current efficiency).
EXAMPLE 10
This example illustrates the coupling of CO to squaric acid in acetonitrile.
Acetonitrile (60 mL) and Bu 4 NBr (3.0 g) were stirred under 1000 psig CO and a direct current (approximately 200 mA) was applied for 5 h. The gas was vented and the electrolysis mixture was then analyzed for squaric acid (0.31 wt. %, 0.16 g 8.0% current efficiency).
EXAMPLE 11
This example illustrates the coupling of CO to squaric acid in n-butyronitrile.
n-Butyronitrile (60 mL) and Bu 4 NBr (3.0 g) were stirred under 1000 psig CO and a direct current (approximately 100 mA) was applied until 11.7 mF charge had passed. The gas was vented and the resultant electrolysis mixture was analyzed for squaric acid (0.20 wt. %, 0.10 g, 16% current efficiency).
EXAMPLE 12
This example illustrates the coupling of CO to squaric acid in pivalonitrile.
Pivalonitrile (60 mL) and Bu 4 NBr (3.0 g) were stirred under 1000 psig CO and a direct current (approximately 100 mA) was applied for 5.5 h. The gas was vented and the resultant electrolysis mixture was analyzed for squaric acid (0.08 wt. %, 0.04 g 2.0% current efficiency.
EXAMPLE 13
This example illustrates the coupling of CO to squaric acid in valeronitrile.
Valeronitrile (60 mL) and Bu 4 NBr (3.0 g) were stirred under 1000 psig CO and a direct current (30 to 100 mA) was applied until 10.3 mF charge had passed. The gas was vented and the resultant solids were separated from the electrolysis mixture by filtration, washed with valeronitrile, and dried (0.93 g). Analysis of these solids showed that they contained 5.82 wt. % squaric acid (0.05 g, 9.2% current efficiency).
EXAMPLE 14
This example illustrates the coupling of CO to squaric acid in benzonitrile.
Benzonitrile (60 mL) and Bu 4 NBr (3.0 g) were stirred under 1000 psig CO and a direct current (approximately 100 mA) was applied for 5.5 h. The gas was vented and the resultant electrolysis mixture was analyzed for squaric acid. No squaric acid was detected.
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An improved process for the preparation of squaric acid, its complexes and/or salts, by means of a process for the electrolytic cathodic reductive tetramerization of carbon monoxide, involving the usage of an anhydrous aliphatic nitrile solvent containing from 3 to about 8 carbon atoms.
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