US4007745A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Filter
Assignee: Celanese Corp
•
Filing: 1974-03-12
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Granted: 1977-02-15
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Expires: 1994-03-12
Abstract
Abstract Improved aerosol filters, particularly cigarette filters, are prepared by imparting a patterned surface, preferably a plurality of longitudinal grooves, to a web of a synthetic thermoplastic fibrous material, preferably a tow of longitudinally aligned crimped continuous cellulose acetate filaments, and forming the resultant patterned web into a filter of the desired form.
Inventors
- 👤 John Courtright Randall
- 👤 Charles Herbert Keith
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 18:04
CPC Classifications
A; A24; A24D; A24D3/00; A24D3/02; A24D3/0204; Y; Y10; Y10S; Y10S55/00; Y10S55/05
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
43 words
A cigarette filter comprising a gathered web of substantially longitudinally aligned continuous, crimped, opened cellulose acetate filaments, said web having a series of longitudinally extending substantially rectangular grooves along the surface thereof said grooves forming a multitude of triangular shaped channels for smoke.
Claim 2
Dependent Claim
43 words
A cigarette filter comprising a gathered web of substantially longitudinally aligned continuous, crimped, opened cellulose acetate filaments, said web having a series of longitudinally extending substantially rectangular grooves along the surface thereof said grooves forming a multitude of triangular shaped channels for smoke.
Claim 3
Dependent Claim
38 words
The filter of claim 1 having a smoke removal efficiency to pressure drop relationship over a pressure drop range of 40-90 mm H 2 O expressed by the equation: S.R.E. = 40.2 + 0.295 Δ P ± 7.7.
References Cited (Backward Citations)
CA669992A
Cited
US2464301A
Cited
GB745245A
Cited
US3238852A
Cited
US2931748A
Cited
US3226280A
Cited
US3224453A
Cited
US3180911A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-02-15 | 1980-08-16 | 1981-02-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-02-15 | 1984-08-16 | 1985-02-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-02-15 | 1988-08-16 | 1989-02-15 | $7700.00 | Window Closed / Lapsed |