Patent EP0133420B1 successfully refreshed from Google Patents.
US4478620A
Expired / Lapsed
US
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Air filter
Assignee: Carl Freudenberg KG
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Filing: 1982-12-06
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Granted: 1984-10-23
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Expires: 2002-12-06
Abstract
Abstract An air filter is described which is made of a non-woven fabric and an overlapped synthetic net which are intermittently point bonded together. The net has raised bumps which form the bonding points for the fabric. A filter of this design is structurally strong but does not generate a large air pressure loss.
Inventors
- 👤 Tadashi Tamura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 19:39
CPC Classifications
D; D04; D04H; D04H1/00; D04H1/40; D04H1/58; D04H1/60; B; B01; B01D; B01D39/00; B01D39/14; B01D39/16; B01D39/1607; B01D39/1623; B01D39/163; B01D2239/00; B01D2239/10
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
148 words
An air filter comprising: a non-woven fabric of fibers having an area to weight relationship of less than about 200 g per sq m and being constructed so as to produce an air pressure loss across its thickness of less than about 3.0 mm Water when measured at an air speed of 2 m per sec; a net of synthetic resin strands overlapping and coterminus with the fabric, the net having convex shaped portions of said synthetic resin substantially uniformly distributed along the strands which are raised at least approximately 0.3 mm above the strand surfaces and are directed toward the non-woven fabric; wherein the fabric and net are bonded together by thermal integration of the convex shaped portions of the net and the corresponding overlapping portions of fabric fibers into a matrix arrangement, and wherein unraised portions of said strands are not substantially bonded to said fibers.
Claim 2
Dependent Claim
148 words
An air filter comprising: a non-woven fabric of fibers having an area to weight relationship of less than about 200 g per sq m and being constructed so as to produce an air pressure loss across its thickness of less than about 3.0 mm Water when measured at an air speed of 2 m per sec; a net of synthetic resin strands overlapping and coterminus with the fabric, the net having convex shaped portions of said synthetic resin substantially uniformly distributed along the strands which are raised at least approximately 0.3 mm above the strand surfaces and are directed toward the non-woven fabric; wherein the fabric and net are bonded together by thermal integration of the convex shaped portions of the net and the corresponding overlapping portions of fabric fibers into a matrix arrangement, and wherein unraised portions of said strands are not substantially bonded to said fibers.
Claim 3
Dependent Claim
30 words
A filter according to claim 1 wherein the tacifying temperature of the fabric fibers is at least 50° C. higher than the tacifying temperature of the resin of the net.
Claim 4
Dependent Claim
26 words
A filter according to claim 1 wherein the resin is selected from the group consisting of polyethylene, ethylenevinyl chloride copolymer, ethylene-vinyl acetate copolymer and polyvinyl chloride.
Claim 5
Dependent Claim
28 words
A filter according to claim 1 wherein the fabric fibers are selected from the group consisting of polyester, polyamide, polyacrylonitrile, polyvinyl alcohol, polypropylene, polychlal, polyimide, polyphenol and rayon.
Claim 6
Dependent Claim
22 words
A filter according to claim 1 wherein the convex shaped portions are raised approximately 0.3 to 0.9 mm above the strand surfaces.
Claim 7
Dependent Claim
20 words
A filter according to claim 1 wherein the distance between strand junctions of the net is 8 to 20 mm.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-10-23 | 1988-04-23 | 1988-10-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-10-23 | 1992-04-23 | 1992-10-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-10-23 | 1996-04-23 | 1996-10-23 | $7700.00 | Window Closed / Lapsed |