Patent US5677031A successfully refreshed from Google Patents.
US5677031A
Expired / Lapsed
US
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Porous PTFE structures
Assignee: W.L. Gore and Associates Inc
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Filing: 1995-05-02
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Granted: 1997-10-14
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Expires: 2015-05-02
Abstract
Abstract A porous polytetrafluoroethylene (PTFE) structure particularly for use as a liquid filter comprises particles of granular-type PTFE fused together to form a porous integral network. The structure is formed by spraying an aqueous suspension of granular PTFE particles and baking at a temperature of 335 DEG -350 DEG C. Typically the specific gravity is 0.8 to 1.54. The crystallinity is less than 95%. The structure may be supported on a perforate substrate such as stainless steel mesh.
Inventors
- 👤 Andrew Miller Allan
- 👤 Brian Andrew Barker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 07:05
CPC Classifications
B; B01; B01D; B01D71/00; B01D71/06; B01D71/30; B01D71/32; B01D71/36; B01D39/00; B01D39/14; B01D39/16; B01D39/1638; B01D39/1653; B01D39/1661; B01D67/00; B01D67/0002; B01D67/0004; B01D67/00041; B01D2323/00; B01D2323/08; B01D2323/081; B01D2323/12; B01D2325/00; B01D2325/38; Y; Y10; Y10T; Y10T428/00; Y10T428/24; Y10T428/24273; Y10T428/24322; Y10T428/24942; Y10T428/2495; Y10T428/24967; Y10T428/24992; Y10T428/249921; Y10T428/249953; Y10T428/249955; Y10T428/249958; Y10T428/249978; Y10T428/249979; Y10T428/249986; Y10T428/249987; Y10T428/25; Y10T428/254; Y10T428/26; Y10T428/29; Y10T428/2982; Y10T428/31504; Y10T428/31678; Y10T428/31692; Y10T428/31699; Y10T428/31855; Y10T428/31909; Y10T428/31913; Y10T428/31928; Y10T428/31935; Y10T442/00; Y10T442/30; Y10T442/3854; Y10T442/3878; Y10T442/3919
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
73 words
A porous fused polytetrafluoroethylene structure which consists essentially of a porous sheet of particles of granular-type polytetrafluoroethylene, said particles having an average particle size between 1 and 500 microns, said particles fused together in a manner which forms a fused network of interconnected particles having pores between the particles, and in which the particles are packed in a manner which results in a specific gravity of the sheet of between 0.8 and 1.54.
Claim 2
Dependent Claim
73 words
A porous fused polytetrafluoroethylene structure which consists essentially of a porous sheet of particles of granular-type polytetrafluoroethylene, said particles having an average particle size between 1 and 500 microns, said particles fused together in a manner which forms a fused network of interconnected particles having pores between the particles, and in which the particles are packed in a manner which results in a specific gravity of the sheet of between 0.8 and 1.54.
Claim 3
Dependent Claim
38 words
The structure of claim 1 wherein the particles are composed of a mixture of a) particles of unsintered polytetrafluoroethylene of average particle size of 20-50 microns and b) particles of sintered polytetrafluoroethylene of average size of 30-60 microns.
Claim 4
Dependent Claim
96 words
A filter element for separation of solids from a fluid stream which consists essentially of: (a) a perforate strength member substrate; (b) a porous coating covering the substrate which consists essentially of a porous sheet of particles of granular-type polytetrafluoroethylene that are fused together in a manner which forms a fused network of interconnected particles having pores between the particles, said particles having an average particle size between 1 and 500 microns, and in which the particles are packed in a manner which results in a specific gravity of the sheet of between 0.8 and 1.54.
Claim 5
Dependent Claim
96 words
A filter element for separation of solids from a fluid stream which consists essentially of: (a) a perforate strength member substrate; (b) a porous coating covering the substrate which consists essentially of a porous sheet of particles of granular-type polytetrafluoroethylene that are fused together in a manner which forms a fused network of interconnected particles having pores between the particles, said particles having an average particle size between 1 and 500 microns, and in which the particles are packed in a manner which results in a specific gravity of the sheet of between 0.8 and 1.54.
Claim 6
Dependent Claim
41 words
The filter element of claim 3 wherein the particles of granular-type polytetrafluoroethylene are composed of a mixture of a) particles of unsintered tetrafluoroethylene of average size of 20-50 microns and b) particles of sintered polytetrafluoroethylene of average size of 30-60 microns.
Claim 7
Dependent Claim
46 words
The filter element of claim 4 wherein the perforate strength member substrate is selected from the class consisting of metal mesh, a porous sintered metal, a woven PTFE-based textile material, a woven polypropylene-based textile material, a non-woven PTFE-based textile material, and a non-woven polypropylene-based textile material.
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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) | 2000-10-13 | 2001-04-14 | 2001-10-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-10-13 | 2005-04-14 | 2005-10-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-10-13 | 2009-04-14 | 2009-10-14 | $7700.00 | Window Closed / Lapsed |