Patent US3645890A successfully refreshed from Google Patents.
US3645890A
Expired / Lapsed
US
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Reverse osmosis membranes from crystalline polymers of vinyl methyl ether
Assignee: Hercules LLC
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Filing: 1969-05-06
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Granted: 1972-02-29
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Expires: 1989-05-06
Abstract
Abstract REVERSE OSMOSIS MEMBRANES USEFUL FOR DESALINATION OF WATER COMPRISE THIN FILMS OF CRYSTALLINE HOMOPOLYMERS OR COPOLYMERS OF VINYL METHYL ETHER WHICH ARE EITHER SUPPORTED ON A MICROPOROUS SUBSTRATE OR IN THE FORM OF THIN WALLED HOLLOW FIBERS.
Inventors
- 👤 Carl A Lukach
- 👤 Harold M Spurlin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 09:17
CPC Classifications
B; B01; B01D; B01D61/00; B01D61/02
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) | 1975-02-28 | 1975-08-30 | 1976-02-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-02-28 | 1979-08-30 | 1980-02-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-02-28 | 1983-08-30 | 1984-02-29 | $7700.00 | Window Closed / Lapsed |