US3676335A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for effecting changes in solution concentrations
Assignee: Southern Research Institute
•
Filing: 1970-12-09
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Granted: 1972-07-11
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Expires: 1990-12-09
Abstract
Abstract Efficiency of reverse osmosis separation processes is enhanced by reducing the thickness of the boundary layer formed at the membrane-solution interface. This is accomplished by placing a second membrane, which is substantially permeable to the solution, in a close-spaced relationship to the reverse osmosis membrane. A portion of the solution is withdrawn from the space between the two membranes.
Inventors
- 👤 Robert E Lacey
- 👤 Milton S Mintz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 14:57
CPC Classifications
B; B01; B01D; B01D61/00; B01D61/02; B01D61/025; B01D63/00; B01D63/08; B01D63/082; B01D71/00; B01D71/06; B01D71/08; B01D71/12; B01D71/14; B01D71/16
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
21 words
The process of claim 1 wherein said feed solution is chosen from the group consisting of sea water and brackish water.
Claim 2
Dependent Claim
17 words
The process of claim 2 wherein said first membrane comprises a felted mat of a fibrous material.
Claim 3
Dependent Claim
33 words
The process of claim 3 wherein at least a portion of the feed solution withdrawn from the space between said first and second membranes is recycled back to the entering feed solution stream.
Claim 4
Dependent Claim
11 words
The process of claim 4 wherein the permeate solution comprises water.
Claim 5
Dependent Claim
13 words
The process of claim 5 wherein said reverse osmosis membrane comprises cellulose acetate.
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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 |