US4077885A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Composite dynamic membrane
Assignee: Nederlandse Organisatie voor Toegepast Natuurwetenschappelijk Onderzoek TNO
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Filing: 1975-12-12
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Granted: 1978-03-07
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Expires: 1995-12-12
Abstract
Abstract A composite dynamically formed membrane is described comprising an intermate layer between a solid porous supporting material and the layer of forming particles. In forming the composite dynamic membrane an intermediate layer of inert material which is either granular or fibrous, is deposited on a substantially tubular porous supporting device and on this there is deposited a second layer of an inert material, the ratio of the particle diameters between the second and the first layer being between 1:10 and 1:1,000. The fine particles for this second layer may be blended with the particles of membrane forming material. Dynamic membranes are employed in reverse osmosis, which more in particular is widely used for the desalination of aqueous liquids.
Inventors
- 👤 Jan Willem van Heuven
- 👤 Roelof Karl Bloebaum
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 11:00
CPC Classifications
B; B01; B01D; B01D61/00; B01D61/02; B01D61/025; B01D69/00; B01D69/14; B01D69/141; B01D69/142
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
112 words
An improved device for effecting reverse osmosis, provided with a dynamically formed membrane, which is composed of a porous supporting device, an intermediate layer of an inert material consisting essentially of a member selected from the group consisting of glass fibers and asbestos fibers that is hardly or not deformable and a layer of membrane-forming material, wherein the improvement comprises that on the intermediate layer a second layer comprising granular inert material selected from the group consisting of silicon dioxide and carbon black is provided, of a substantially smaller diameter, the ratio between the particle diameter of this last mentioned material and that of the intermediate layer being between 1:10 and 1:1,000.
Claim 2
Dependent Claim
112 words
An improved device for effecting reverse osmosis, provided with a dynamically formed membrane, which is composed of a porous supporting device, an intermediate layer of an inert material consisting essentially of a member selected from the group consisting of glass fibers and asbestos fibers that is hardly or not deformable and a layer of membrane-forming material, wherein the improvement comprises that on the intermediate layer a second layer comprising granular inert material selected from the group consisting of silicon dioxide and carbon black is provided, of a substantially smaller diameter, the ratio between the particle diameter of this last mentioned material and that of the intermediate layer being between 1:10 and 1:1,000.
Claim 3
Dependent Claim
22 words
A device according to claim 1, wherein the granular inert material is provided on to the intermediate layer as a simple layer.
Claim 4
Dependent Claim
23 words
A device according to claim 1, wherein the granular material is provided on to the intermediate layer blended together with the membrane-forming material.
Claim 5
Dependent Claim
47 words
A device according to claim 1, wherein the first intermediate layer comprises non fibrous inert granular material and the ratio between the particle diameter of the granular material deposited on to the intermediate layer and the granular material of the intermediate layer is between 1:50 and 1:1,000.
Claim 6
Dependent Claim
142 words
An improved method for preparing a dynamic membrane device according to claim 1, wherein first an intermediate layer and thereafter a layer of membrane-forming material is deposited on to a porous supporting device by means of a fluid flow, the improvement comprising that the inert material that is hardly or not deformable for the formation of the first intermediate layer consisting essentially of a member selected from the group consisting of glass fibers and asbestos fibers and the inert granular material selected from the group consisting of silicon dioxide and carbon black to be deposited on the first intermediate layer are deposited in a first and a second layer, the ratio between the average particle diameter of the inert granular material of the second layer and the smallest average diameter of the particles of the first layer, being between 1:10 and 1:1,000.
Claim 7
Dependent Claim
90 words
A method for preparing an improved device according to claim 5, an intermediate layer of inert particles and a layer of membrane-forming material being deposited on to a porous substrate, the improvement comprising that the inert granular material having the smallest diameter to be deposited on the (first) intermediate layer is deposited on to the intermediate layer, simultaneously and blended with the membrane-forming material, the ratio between the particle diameter of the inert granular material and the average particle diameter of the (first) intermediate layer being between 1:10 and 1:1,000.
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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) | 1981-03-06 | 1981-09-05 | 1982-03-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-03-06 | 1985-09-05 | 1986-03-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-03-06 | 1989-09-05 | 1990-03-07 | $7700.00 | Window Closed / Lapsed |