US4983434A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Filter laminates
Assignee: W.L. Gore and Associates Inc
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Filing: 1989-09-25
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Granted: 1991-01-08
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Expires: 2009-09-25
Abstract
Abstract An expanded porous polytetrafluoroethylene (PTFE) membrane is employed in laminar conjunction with an polytetrafluoroethylene felt; in which the felt is reinforced with a woven scrim.
Inventors
- 👤 Robert L. Sassa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 16:31
CPC Classifications
B; B01; B01D; B01D39/00; B01D39/08; B01D39/083; B32; B32B; B32B5/00; B32B5/22; B32B5/24; B32B5/245; B01D69/00; B01D69/10; B01D69/107; B01D69/1071; B01D71/00; B01D71/06; B01D71/30; B01D71/32; B01D71/36; B32B27/00; B32B27/12; B32B5/02; B32B5/06; B32B5/18; B32B5/26; B32B7/00; B32B7/04; B32B7/12; B01D2239/00; B01D2239/04; B01D2239/0471; B01D2239/06; B01D2239/065; B01D2239/0654; B01D2239/0659; B01D2239/0681; B01D2239/12; B01D2239/1258; B32B2262/00; B32B2262/02; B32B2262/0253; B32B2266/00; B32B2266/02; B32B2266/0214; B32B2266/025; B32B2307/00; B32B2307/70; B32B2307/724; B32B2437/00; Y; Y10; Y10T; Y10T428/00; Y10T428/13; Y10T428/1334; Y10T428/1352; Y10T428/1362; Y10T428/1366; Y10T428/249921; Y10T428/249953; Y10T428/24996; Y10T428/249981; Y10T428/249982; Y10T428/249985; Y10T428/31504; Y10T428/3154; Y10T428/31544; Y10T442/00; Y10T442/10; Y10T442/102; Y10T442/159
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
44 words
A laminate comprising: (a) an expanded porous polytetrafluoroethylene membrane having an air permeability of at least 0.01 cubic feet per square foot at 0.5 inch water gauge; (b) a felt comprising a web of polytetrafluoroethylene staple fiber supported by a woven scrim of polytetrafluoroethylene.
Claim 2
Dependent Claim
44 words
A laminate comprising: (a) an expanded porous polytetrafluoroethylene membrane having an air permeability of at least 0.01 cubic feet per square foot at 0.5 inch water gauge; (b) a felt comprising a web of polytetrafluoroethylene staple fiber supported by a woven scrim of polytetrafluoroethylene.
Claim 3
Dependent Claim
25 words
The laminate of claim 1 wherein the woven scrim is attached to the felt by needle punch intermingling of the felt fibers with the scrim.
Claim 4
Dependent Claim
16 words
The laminate of claim 2 wherein the membrane is attached to the felt by an adhesive.
Claim 5
Dependent Claim
12 words
The laminate of claim 3 wherein the adhesive is a fluorinated polymer.
Claim 6
Dependent Claim
12 words
The laminate of claim 1 wherein the felt comprises expanded porous polytetrafluoroethylene.
Claim 7
Dependent Claim
11 words
The laminate of claim 1 wherein the felt comprises non-expanded polytetrafluoroethylene.
Claim 8
Dependent Claim
27 words
The laminate of claim 1 wherein the felt contains up to 25 weight percent of fiber selected from carbon fiber, polyimide fiber, glass fiber, and mixtures thereof.
Claim 9
Dependent Claim
11 words
The laminate of claim 1 in the form of a cloth.
Claim 10
Dependent Claim
12 words
The laminate of claim 1 in the form of a filter bag.
Claim 11
Dependent Claim
13 words
The laminate of claim 1 wherein the woven scrim is expanded porous polytetrafluoroethylene.
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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) | 1994-01-07 | 1994-07-09 | 1995-01-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-01-07 | 1998-07-09 | 1999-01-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-01-07 | 2002-07-09 | 2003-01-08 | $7700.00 | Window Closed / Lapsed |