US4188418A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Separation process
Assignee: Lever Brothers Co
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Filing: 1978-02-21
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Granted: 1980-02-12
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Expires: 1998-02-21
Abstract
Abstract The flux rate of ultrafiltration membranes is markedly improved by the presence of inert, water-insoluble, impervious particles, particularly of metals and their alloys, distributed wholly within the membrane. The particles are particularly effective in the region adjacent the interface of the membrane with a support surface and may be distributed previously in the casting dope, or applied in a thin coating to the surface on which the membrane is subsequently prepared by casting from the dope. The membrane is in flat, tubular or filamentary form.
Inventors
- 👤 Robert M. Livingston
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 15:52
CPC Classifications
B; B01; B01D; B01D69/00; B01D69/14; B01D69/141; B01D69/148; B01D61/00; B01D61/14; B01D61/145
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
103 words
A method of preparing an ultra-filtration membrane of improved flux comprising the steps of: (a) applying to a support surface a slurry of a finely divided inert, impervious and water-isoluble solid particulate flux improver contained in a volatile solvent, (b) evaporating said solvent whereby a thin layer of the flux improver is left on said support surface, (c) applying a film of a casting dope consisting essentially of a solution of a film-forming organic polymer in a non-volatile solvent over the said layer of flux improver, and (d) promptly thereafter contacting the said film with water to leach out the said non-volatile solvent.
Claim 2
Independent Claim
103 words
A method of preparing an ultra-filtration membrane of improved flux comprising the steps of: (a) applying to a support surface a slurry of a finely divided inert, impervious and water-isoluble solid particulate flux improver contained in a volatile solvent, (b) evaporating said solvent whereby a thin layer of the flux improver is left on said support surface, (c) applying a film of a casting dope consisting essentially of a solution of a film-forming organic polymer in a non-volatile solvent over the said layer of flux improver, and (d) promptly thereafter contacting the said film with water to leach out the said non-volatile solvent.
Claim 3
Dependent Claim
32 words
A method according to claim 1 in which the flux improver is applied to the said surface in the said slurry at a concentration of from 5-500 milligrammes per cm 2 .
References Cited (Backward Citations)
US2574533A
Cited
US3555129A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-02-11 | 1983-08-13 | 1984-02-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-02-11 | 1987-08-13 | 1988-02-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-02-11 | 1991-08-13 | 1992-02-12 | $7700.00 | Window Closed / Lapsed |