Patent US4100323A successfully refreshed from Google Patents.
US4100323A
Expired / Lapsed
US
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Scrimless filter felt
Assignee: EIDP Inc
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Filing: 1977-10-07
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Granted: 1978-07-11
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Expires: 1997-10-07
Abstract
Abstract A scrimless, dimensionally stable filter felt suitable for high temperature gas filtration is comprised of at least 80% by weight poly(m-phenylene isophthalamide) staple fibers having at least a low degree of crystallinity and a staple length of 4 to 16 cm., and has a felt density of 0.15 to 0.4 g./cm. 3 and an air permeability of 3 to 30 m. 3 /min./m. 2 (0° C. basis pressure differential = 1.27 g./cm. 3 .
Inventors
- 👤 Herman Hans Forsten
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 23:03
CPC Classifications
D; D04; D04H; D04H1/00; D04H1/40; D04H1/44; D04H1/46; D04H1/48; B; B01; B01D; B01D39/00; B01D39/14; B01D39/16; B01D39/1607; B01D39/1623; Y; Y10; Y10T; Y10T428/00; Y10T428/29; Y10T428/2904; Y10T442/00; Y10T442/50; Y10T442/56
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
81 words
A needled, dimensionally stable, scrimless filter felt comprised of at least 80% by weight poly(m-phenylene isophthalamide) staple fibers having at least a low degree of crystallinity and a staple length of 4 to 16 cm., a felt density of 0.15 to 0.4 g./cm. 3 and an air permeability of 3 to 30 m. 3 /min./m. 2 (0° C. basis, pressure differential = 1.27 g./cm. 2 ), said felt having been heated at 280-350° C under restraint for 1 to 900 seconds.
Claim 2
Dependent Claim
81 words
A needled, dimensionally stable, scrimless filter felt comprised of at least 80% by weight poly(m-phenylene isophthalamide) staple fibers having at least a low degree of crystallinity and a staple length of 4 to 16 cm., a felt density of 0.15 to 0.4 g./cm. 3 and an air permeability of 3 to 30 m. 3 /min./m. 2 (0° C. basis, pressure differential = 1.27 g./cm. 2 ), said felt having been heated at 280-350° C under restraint for 1 to 900 seconds.
Claim 3
Dependent Claim
15 words
The felt of claim 1 wherein 100% by weight of the fibers are poly(m-phenylene isophthalamide).
Claim 4
Dependent Claim
16 words
The felt of claim 2 wherein the felt density is 0.2 to 0.3 g./cm. 3 .
Claim 5
Dependent Claim
17 words
The felt of claim 3 wherein the permeability is 6 to 10 m. 3 /min./m. 2 .
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) | 1981-07-10 | 1982-01-09 | 1982-07-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-07-10 | 1986-01-09 | 1986-07-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-07-10 | 1990-01-09 | 1990-07-11 | $7700.00 | Window Closed / Lapsed |