US3823086A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Pretreatment for reverse osmosis process
Assignee: Culligan International Co
•
Filing: 1973-01-22
•
Granted: 1974-07-09
•
Expires: 1993-01-22
Abstract
Abstract A PRETREATMENT PROCESS FOR INCREASING THE USEFUL LIFE OF A REVERSE OSMOSIS MEMBRANE COMPRISING PASSING AT LEAST A PORTION OF A REVERSE OSMOSIS MOLDULE INFLUENT THROUGH A STRONG BASIC TYPE II AMION EXCHANGE RESIN UNTIL CARBONATE IONS ARE DETECTED IN THE EXCHANGE RESIN EFFLUENT. A REVERSE OSMOSIS MODULE INFLUENT IS THUS CONTROLLED TO CONTINUOUSLY HAVE A PH VALUE BELOW 8, WHICH GREATLY INCREASE THE LIFE OF A CELLULOSE ACETATE REVERSE OSMOSIS MEMBRANE. THE CAPACITY OF THE ANION EXCHANGE RESIN IS EXTENDED BEYOND THE CONVENTIONAL END POINT FOR SUCH RESIN.
Inventors
- 👤 K Schmidt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 16:02
CPC Classifications
B; B01; B01D; B01D61/00; B01D61/02; B01D61/025; B01D61/08; C; C02; C02F; C02F1/00; C02F1/44; C02F1/441; B01D2311/00; B01D2311/04
Claims Analysis
Total Claims: 0
No claims parsed yet. Click Sync Now above to re-index claims from Google Patents.
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) | 1977-07-08 | 1978-01-07 | 1978-07-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-07-08 | 1982-01-07 | 1982-07-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-07-08 | 1986-01-07 | 1986-07-09 | $7700.00 | Window Closed / Lapsed |