US3676203A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Semipermeable membranes
Assignee: United States Department of the Interior
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Filing: 1970-08-07
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Granted: 1972-07-11
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Expires: 1990-08-07
Abstract
Abstract SEMIPERMEABLE COMPOSITE MEMBRANES ARE PREPARED BY COATING POLYACRYLIC ACID ON A POROUS SUPPORT. THE RESULTING MEMBRANES EXHIBIT SUPERIOR SALT REJECTING CAPABILITY AND FIND PARTICULAR UTILITY IN DESALINATION OF WATER BY REVERVE OSMOSIS.
Inventors
- 👤 Samuel B Sachs
- 👤 Robert L Riley
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 13:04
CPC Classifications
B; B01; B01D; B01D71/00; B01D71/06; B01D71/40; B01D71/401; B01D69/00; B01D69/12; Y; Y10; Y10T; Y10T428/00; Y10T428/249921; Y10T428/249953; Y10T428/249967; Y10T428/249969; Y10T428/24997; Y10T428/249978; Y10T428/26; Y10T428/263; Y10T428/31504; Y10T428/31551; Y10T428/31645; Y10T428/31678; Y10T428/31692
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) | 1975-07-11 | 1976-01-10 | 1976-07-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-07-11 | 1980-01-10 | 1980-07-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-07-11 | 1984-01-10 | 1984-07-11 | $7700.00 | Window Closed / Lapsed |