US3429957A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for continuously casting a semi-permeable membrane
Assignee: Gulf General Atomic Inc
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Filing: 1965-07-06
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Granted: 1969-02-25
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Expires: 1985-07-06
Abstract
No abstract record available.
Inventors
- 👤 Ulrich Merten
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 05:46
CPC Classifications
B; B01; B01D; B01D69/00; B01D69/04; B01D71/00; B01D71/06; B01D71/08; B01D71/12; B01D71/14; B29; B29C; B29C41/00; B29C41/24; B29C41/26; B29C41/34; B29C41/36; B29C67/00; B29C67/20; B29C67/202; B01D2323/00; B01D2323/42
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
113 words
A PROCESS FOR MAKING A NONUNIFORM SEMIPERMEABLE MEMBRANE, WHICH PROCESS COMPRISES CONTINUOUSLY CASTING A FILM OF A FLUID MEMBRANE-FORMING SOLUTION COOLED TO A TEMPERATRE OF ABOUT -8*C, UPON A MOVING ENDLESS FLAT SMOOTH SURFACE HAVING A HIGHER TEMPERATURE, SAID SOLUTION CONTAINING CELLULOSE ACETATE AND ACETONE, BY EVAPORATING ACETONE FROM ONE SURFACE OF SAID CAST FILM BY EXPOSING SAID SURFACE OF SAID FILM TO A FORCED CIRCULATION OF AIR FOR ABOUT A MINUTE, IMMERSING SAID FILM AFTER SAID EVAPORATION IN WATER AT A TEMPERATURE OF ABOUT 1*C. TO SET UP SAID CAST FILM INT A NONUNIFORM SEMIPERMEABLE MEMBRANE, AND REMOVING SAID SET-UP MEBRANE FROM THE ENDLESS SURFACE WHILE SAID MEMBRANE IS IMMERSED IN WATER.
Claim 2
Dependent Claim
113 words
A PROCESS FOR MAKING A NONUNIFORM SEMIPERMEABLE MEMBRANE, WHICH PROCESS COMPRISES CONTINUOUSLY CASTING A FILM OF A FLUID MEMBRANE-FORMING SOLUTION COOLED TO A TEMPERATRE OF ABOUT -8*C, UPON A MOVING ENDLESS FLAT SMOOTH SURFACE HAVING A HIGHER TEMPERATURE, SAID SOLUTION CONTAINING CELLULOSE ACETATE AND ACETONE, BY EVAPORATING ACETONE FROM ONE SURFACE OF SAID CAST FILM BY EXPOSING SAID SURFACE OF SAID FILM TO A FORCED CIRCULATION OF AIR FOR ABOUT A MINUTE, IMMERSING SAID FILM AFTER SAID EVAPORATION IN WATER AT A TEMPERATURE OF ABOUT 1*C. TO SET UP SAID CAST FILM INT A NONUNIFORM SEMIPERMEABLE MEMBRANE, AND REMOVING SAID SET-UP MEBRANE FROM THE ENDLESS SURFACE WHILE SAID MEMBRANE IS IMMERSED IN WATER.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1972-02-25 | 1972-08-26 | 1973-02-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1976-02-25 | 1976-08-26 | 1977-02-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1980-02-25 | 1980-08-26 | 1981-02-25 | $7700.00 | Window Closed / Lapsed |