US3808303A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ether treatment of nitrogen-containing polymer membranes
Assignee: EIDP Inc
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Filing: 1971-12-30
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Granted: 1974-04-30
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Expires: 1991-12-30
Abstract
Abstract THE SOLUTE REJECTION PROPERTIES OF PERMSELECTIVE MEMBRANE MADE OF NITROGEN-LINKED SYNTHETIC ORGANIC POLYMERS IN REVERSE OSMOSIS PROCESSES ARE IMPROVED BY EXPOSING THE MEMBRANES TO SOLUTIONS OF ETHERS HAVING CARBON TO OXYGEN ATOMIC RATIOS BETWEEN ABOUT 2.5:1 AND ABOUT 5:1, AND HAVING FORMULA WEIGHTS LARGER THAN ABOUT 400, SUCH TREATMENTS ARE EVEN MORE EFFECTIVE WHEN COMBINED WITH EXPOSURE OF THE MEMBRANES TO WATER AT TEMPERATURES OF 5* TO 90*C.
Inventors
- 👤 F Smith
- 👤 J Ganci
- 👤 J Jensen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 17:29
CPC Classifications
B; B01; B01D; B01D67/00; B01D67/0081; B01D67/0088; B01D71/00; B01D71/06; B01D71/56
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) | 1977-04-29 | 1977-10-29 | 1978-04-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-04-29 | 1981-10-29 | 1982-04-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-04-29 | 1985-10-29 | 1986-04-30 | $7700.00 | Window Closed / Lapsed |