US3905787A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Filter
Assignee: Fitesa Simpsonville Inc
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Filing: 1974-12-23
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Granted: 1975-09-16
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Expires: 1994-12-23
Abstract
Abstract A filtering device wherein a nonwoven fabric is secured to a filter layer on the downstream side thereof for supporting the filter layer, the nonwoven fabric being provided with a plurality of intersecting slits which form flap valves which open to allow the passage of a gaseous medium through the device, the combined area of the flap valves being 35 to 60 percent of the area of the nonwoven fabric and the nonwoven fabric having a weight within the range of 13 to 34 grams per square meter. Preferably, the fabric has a weight of 13 to 20 grams per square meter and the total flap valve area is 40 to 50 percent of the area of the fabric.
Inventors
- 👤 Fred S Roth
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 14:35
CPC Classifications
B; B01; B01D; B01D46/00; B01D46/0084; B01D46/0089; B01D46/10; B01D46/42; B01D46/4272; Y; Y10; Y10S; Y10S55/00; Y10S55/31
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
76 words
A FILTERING DEVICE, COMPRISING A. A FILTER LAYER FOR REMOVING PARTICULATE MATTER FROM A GASEOUS MEDIUM PASSED THRETHROUGH, AND B. A LAYER OF NONWOVEN FABRIC POSITIONED IN CONTACT WITH THE FILTER LAYER ON THE DOWNSTREAM SIDE THEREOF FOR SUPPORTING SAID FILTER LAYER, SAID NONWOVEN FABRIC HAVING THEREIN A PLURALITY OF SLITS FORMING A PLURALITY OF FLAP VALVES THE COMBINED AREA OF SAID FLAP VALVES BEING 35 TO 60 PERCENT OF THE AREA OF SAID NONWOVEN FABRIC.
Claim 2
Dependent Claim
76 words
A FILTERING DEVICE, COMPRISING A. A FILTER LAYER FOR REMOVING PARTICULATE MATTER FROM A GASEOUS MEDIUM PASSED THRETHROUGH, AND B. A LAYER OF NONWOVEN FABRIC POSITIONED IN CONTACT WITH THE FILTER LAYER ON THE DOWNSTREAM SIDE THEREOF FOR SUPPORTING SAID FILTER LAYER, SAID NONWOVEN FABRIC HAVING THEREIN A PLURALITY OF SLITS FORMING A PLURALITY OF FLAP VALVES THE COMBINED AREA OF SAID FLAP VALVES BEING 35 TO 60 PERCENT OF THE AREA OF SAID NONWOVEN FABRIC.
Claim 3
Dependent Claim
24 words
The filtering device of claim 1 wherein the nonwoven fabric has a weight within the range of 13 to 34 grams per square meter.
Claim 4
Dependent Claim
25 words
The device of claim 1 wherein the combined area of said flap valves is 40 to 50 percent of the total area of said fabric.
Claim 5
Dependent Claim
84 words
A filtering device comprising a. a filter layer for removing particular matter from a gaseous medium passed therethrough, and b. a layer of porous nonwoven fabric bonded to the filter layer on the downstream side thereof, said nonwoven fabric having therein a plurality of intersecting slits forming a plurality of flap valves, the combined area of said flap valves being 40 to 50 percent of the area of the nonwoven fabric, said fabric having a weight of 13 to 20 grams per square meter.
Claim 6
Dependent Claim
84 words
A filtering device comprising a. a filter layer for removing particular matter from a gaseous medium passed therethrough, and b. a layer of porous nonwoven fabric bonded to the filter layer on the downstream side thereof, said nonwoven fabric having therein a plurality of intersecting slits forming a plurality of flap valves, the combined area of said flap valves being 40 to 50 percent of the area of the nonwoven fabric, said fabric having a weight of 13 to 20 grams per square meter.
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) | 1978-09-15 | 1979-03-17 | 1979-09-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-15 | 1983-03-17 | 1983-09-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-15 | 1987-03-17 | 1987-09-16 | $7700.00 | Window Closed / Lapsed |