Patent US4093533A successfully refreshed from Google Patents.
US4093533A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Bonded asbestos diaphragms
Assignee: CHEMTECH ROYALTY ASSOCIATES LP
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Filing: 1975-12-12
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Granted: 1978-06-06
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Expires: 1995-12-12
Abstract
Abstract Improved asbestos diaphragms for use in electrolytic chlor-alkali cells are prepared by using polymeric fluorocarbons as binders for mixtures of chyrsotile asbestos and crocidolite asbestos.
Inventors
- 👤 Richard N. Beaver
- 👤 Charles W. Becker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 14:08
CPC Classifications
C; C25; C25B; C25B1/00; C25B1/01; C25B1/34; C25B1/46; C25B13/00; C25B13/04; C25B13/05; C25B13/06; C25B13/08
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
65 words
An improved diaphragm for use in an electrolytic cell wherein brine is electrolyzed to produce chlorine, caustic, and hydrogen and wherein a polymeric fluorocarbon-bonded asbestos diaphragm is positioned between the electrodes, the improvement which comprises the use of a mixture of crocidolite and chrysotile as the asbestos, said mixtures of crocidolite/chrysotile being of a weight ratio in the range of about 33/67 to about 75/25.
Claim 2
Dependent Claim
65 words
An improved diaphragm for use in an electrolytic cell wherein brine is electrolyzed to produce chlorine, caustic, and hydrogen and wherein a polymeric fluorocarbon-bonded asbestos diaphragm is positioned between the electrodes, the improvement which comprises the use of a mixture of crocidolite and chrysotile as the asbestos, said mixtures of crocidolite/chrysotile being of a weight ratio in the range of about 33/67 to about 75/25.
Claim 3
Dependent Claim
15 words
The improved diaphragm of claim 1 wherein the weight ratio of crocidolite/chrysolite is about 50/50.
Claim 4
Dependent Claim
39 words
The improved diaphragm of claim 1 wherein the polymeric fluorocarbon employed in the polymeric fluorocarbon-bonded diaphragm is selected from the group consisting of polymers and copolymers of tetrafluoroethylene, trifluoroethylene, monochlorotrifluoroethylene, dichlorodifluoroethylene, vinyl fluoride, vinylidene fluoride, and fluorinated olefin polymers.
Claim 5
Dependent Claim
13 words
The improved diaphragm of claim 1 wherein the polymeric fluorocarbon is polyvinylidene fluoride.
Claim 6
Dependent Claim
12 words
The improved diaphragm of claim 1 wherein the polymeric fluorocarbon is polytetrafluoroethylene.
Claim 7
Dependent Claim
14 words
The improved diaphragm of claim 1 wherein the polymeric fluorocarbon is fluorinated ethylene/propylene copolymer.
References Cited (Backward Citations)
US3505200A
Cited
US3723264A
Cited
US3853721A
Cited
US3980613A
Cited
US3945910A
Cited
US3928166A
Cited
US4000057A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-06-05 | 1981-12-05 | 1982-06-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-06-05 | 1985-12-05 | 1986-06-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-06-05 | 1989-12-05 | 1990-06-06 | $7700.00 | Window Closed / Lapsed |