US3822330A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Semi-permeable membranes
Assignee: Babcock International Ltd
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Filing: 1972-02-17
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Granted: 1974-07-02
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Expires: 1992-02-17
Abstract
Abstract A PROCESS FOR THE MANUFACTURE OF A SEMI-PERMEABLE MEMBRANE WHICH COMPRISES (A) PREPARING A CASTING SOLUTION CONTAINING A VINYL COPOLYMER AND AN ORGANIC POLAR SOLVENT; (B) CASTING THE CASTING SOLUTION AS A FILM; (C) EVAPORATING THE SOLVENT FROM THE FILM FROM STEP (B); (D) CONTACTING THE FILM FROM STEP (C) WITH WATER FOR AT LEAST 10 MINUTES. THE SEMI-PERMEABLE MEMBRANES ARE USED FOR REVERSE OSMOSIS OR HYPERFILTRATION TREATMENT OF VARIOUS FEED SOLUTIONS.
Inventors
- 👤 Muir W Mcclements
- 👤 R Livingston
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 14:38
CPC Classifications
B; B01; B01D; B01D71/00; B01D71/06; B01D71/40; B01D71/401; B01D67/00; B01D67/0002; B01D67/0009; B01D67/00091; B01D67/0011; B01D67/00111; B01D71/08; B01D71/12; B01D71/14; B01D71/16; B01D2323/00; B01D2323/08; B01D2323/12; B01D2323/28; B01D2323/286
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-07-01 | 1977-12-31 | 1978-07-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-07-01 | 1981-12-31 | 1982-07-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-07-01 | 1985-12-31 | 1986-07-02 | $7700.00 | Window Closed / Lapsed |