Patent US3552400A successfully refreshed from Google Patents.
US3552400A
Expired / Lapsed
US
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Filter plug of staple fiber filter elements and the like
Assignee: Filtrona Richmond Inc
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Filing: 1967-06-08
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Granted: 1971-01-05
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Expires: 1987-06-08
Abstract
Abstract The production of a filter plug comprising staple fiber smoke filter elements and the like directly from a continuous filamentary tow. The plug comprises filamentary staple fibers and has an AFC hardness in excess of 180 and a density of less than 0.120 grams per cubic centimeter. The filter plugs have functional and physical characteristics comparable to prior art filter elements, but require 20-30 percent less material. The filter elements can be supplemented by various additive materials.
Inventors
- 👤 Richard M Berger
- 👤 Reavis C Sproull
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 18:53
CPC Classifications
D; D01; D01G; D01G1/00; A; A24; A24D; A24D3/00; A24D3/02; A24D3/0204; A24D3/0208; D01D; D01D10/00; D01D10/04; D01D10/049
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
29 words
In a cigarette including a filter section and a tobacco section, the improvement which is characterized by said filter section comprising an elongated plug as defined in claim 1.
Claim 2
Dependent Claim
16 words
The filter element defined in claim 1 wherein said AFC hardness is in excess of 200.
Claim 3
Dependent Claim
38 words
The filter element defined in claim 1 wherein for a section of approximately 20 mm. in length and approximately 7.9 mm. in diameter said plug has a total particulate matter filtration efficiency of at least about 25 percent.
Claim 4
Dependent Claim
20 words
The filter element defined in claim 1 wherein said plug has substantially uniform physical characteristics across all cross sections thereof.
Claim 5
Dependent Claim
42 words
The filter element defined in claim 1 wherein said plug comprises a porous matrix defined by a multiplicity of staple fibers wherein substantially all of said fibers are bonded to adjacent fibers at points of contact of said fibers with each other.
Claim 6
Dependent Claim
22 words
The filter element defined in claim 1 wherein said staple fibers are formed, at least in predominant part of plasticized cellulose acetate.
Claim 7
Dependent Claim
89 words
In a filter element comprising an elongated plug in the form of a porous matrix defined by a multiplicity of filamentary staple fibers wherein substantially all of said fibers are bonded to adjacent fibers at points of contact of said fibers with each other, said plug having an AFC hardness in excess of 180 and a density of less than 0.120 grams per cubic centimeter, the improvement which is characterized by at least a predominate portion of said staple fibers extending transverse to the elongated axis of said plug.
Claim 8
Dependent Claim
26 words
The filter element defined in claim 8 wherein at least a predominant portion of said staple fibers are longer than the minimum width of said plug.
Claim 9
Dependent Claim
86 words
A filter element comprising an air permeable form retaining deformation resistant rod comprising a plurality of filamentary fibers of between one-eighth inch to 2 inches in length cut from a continuous filamentary tow, at least some of said fibers laying transversely to the longitudinal axis of the rod and substantially all of said fibers being bonded to adjacent fibers at their points of contact, the rod having an AFC hardness in eXcess of 180 and a density of not more than 0.120 grams per cubic centimeter.
Claim 10
Dependent Claim
18 words
A filter according to claim 10 wherein the fibers have a length of approximately three-eighths of an inch.
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) | 1974-01-04 | 1974-07-06 | 1975-01-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-01-04 | 1978-07-06 | 1979-01-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-01-04 | 1982-07-06 | 1983-01-05 | $7700.00 | Window Closed / Lapsed |