Patent US3700591A successfully refreshed from Google Patents.
US3700591A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cleaning of used membrane with oxalic acid
Assignee: United States Department of the Interior
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Filing: 1970-09-24
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Granted: 1972-10-24
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Expires: 1990-09-24
Abstract
Abstract A METHOD FOR CLEANING AND REJUVENATING A USED REVERSE OSMOSIS MEMBRANCE BY TREATING THE MEMBRANE IN SITU WITH A SOLUTION OF OXALIC ACID. NOT ONLY ARE DELETERIOUS DEPOSITS REMOVED FROM THE MEMBRANE, BUT THE ORGINAL OSMOTIC PROOPERTIES OF THE MEMBRANE MAY BE PARTIALLY RESTORED. THE MEMBRANE PROPERTIES MAY BE FURTHER IMPROVED BY A SUBSEQUENT TREATMENT WITH A SWELLING AGENT OR A HOT WATER SOLUTION.
Inventors
- 👤 Willard S Higley
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 21:54
CPC Classifications
B; B01; B01D; B01D65/00; B01D65/02; B01D61/00; B01D61/02; B01D61/10; B01D2321/00; B01D2321/16; B01D2321/162; B01D2321/28
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) | 1975-10-24 | 1976-04-24 | 1976-10-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-24 | 1980-04-24 | 1980-10-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-24 | 1984-04-24 | 1984-10-24 | $7700.00 | Window Closed / Lapsed |