US4765915A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Porous filter media and membrane support means
Assignee: Dow Chemical Co
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Filing: 1986-04-14
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Granted: 1988-08-23
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Expires: 2006-04-14
Abstract
Abstract A method for filtering liquid or gaseous materials where the filtration is conducted with a porous filter media prepared from an aqueous wet-laid, lofted fiber-reinforced composite sheet, the composite sheet comprising a heat fusible polymer, reinforcing fibers and a binder. The random fiber composite sheet can be selectively lofted or recompressed to form filter media having variable porosity. Also, a membrane support means prepared by applying or treating the fiber-reinforced composite sheet with a discriminating membrane layer.
Inventors
- 👤 Charles F. Diehl
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 12:03
CPC Classifications
D; D04; D04H; D04H1/00; D04H1/40; D04H1/54; B; B01; B01D; B01D39/00; B01D39/02; B01D39/04; B01D39/14; B01D39/16; B01D39/1607; B01D39/1623; B01D39/163; B01D39/20; B01D39/2003; B01D39/2017; B01D39/2024; B01D69/00; B01D69/10; B01D69/108; B01D69/12; B01D69/1213; B01D71/00; B01D71/06; B01D71/76; D21; D21H; D21H27/00; D21H27/08; B01D2239/00; B01D2239/06; B01D2239/0604; B01D2239/065; B01D2239/10; B01D2239/12; B01D2239/1208; B01D2239/1258; Y; Y10; Y10T; Y10T428/00; Y10T428/24; Y10T428/24479; Y10T428/24595; Y10T428/24603; Y10T442/00; Y10T442/60; Y10T442/69
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
53 words
A method for filtering fluids comprising passing fluid containing filterable material through at least one porous filter medium comprising a densified random fiber composite sheet which has been expanded, by heating, in a direction normal to the plane of the sheet and which comprises a heat fusible polymer, reinforcing fibers, and a binder.
Claim 2
Independent Claim
53 words
A method for filtering fluids comprising passing fluid containing filterable material through at least one porous filter medium comprising a densified random fiber composite sheet which has been expanded, by heating, in a direction normal to the plane of the sheet and which comprises a heat fusible polymer, reinforcing fibers, and a binder.
Claim 3
Dependent Claim
13 words
The method of claim 1 where said heat fusible resin is a polyolefin.
Claim 4
Dependent Claim
18 words
The method of claim 2 where said heat fusible resin is a high density polyethylene or crystalline polypropylene.
Claim 5
Dependent Claim
12 words
The method of claim 1 where said reinforcing fibers are glass fibers.
Claim 6
Dependent Claim
18 words
The method of claim 4 where said glass fibers are from about 0.125 to 1.00 inch in length.
Claim 7
Dependent Claim
22 words
The method of claim 1 wherein the heat-expanded composite sheet has been partially recompressed to obtain a desired porosity or bulk density.
Claim 8
Dependent Claim
14 words
The method of claim 1 wherein the heat-expanded composite sheet includes a porosity gradient.
Claim 9
Dependent Claim
44 words
The method of claim 1 wherein the densified composite sheet has a density of from about 0.75 to about 1.75 grams per cubic centimeter and the heat expanded composite sheet has a density of from about 0.2 to about 1.20 grams per cubic centimeter.
Claim 10
Dependent Claim
20 words
The method of claim 1 wherein the heat-expanded composite has a thickness of from about 0.005 to about 0.60 inch.
Claim 11
Dependent Claim
29 words
The method of claim 1 wherein the heat-expanded composite has a thickness which is from about 20 to about 500 percent greater than the densified random fiber composite sheet.
Claim 12
Dependent Claim
28 words
The method of claim 1 wherein the heat-expanded composite has a void volume of from about 20 to about 90 percent of the volume of the resulting sheet.
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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) | 1991-08-23 | 1992-02-22 | 1992-08-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-08-23 | 1996-02-22 | 1996-08-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-08-23 | 2000-02-22 | 2000-08-23 | $7700.00 | Window Closed / Lapsed |