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US4135523A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Tobacco-smoke filters
Assignee: British American Tobacco Investments Ltd
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Filing: 1977-03-11
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Granted: 1979-01-23
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Expires: 1997-03-11
Abstract
Abstract A filter element for a smoking article, such as a cigarette, comprises a generally cylindrical body having at least one helical groove in its peripheral surface and closely wrapped in a material pervious to vapor-phase constituents of the smoke, whereby such constituents are removed by diffusion thereof through said material during passage of the smoke along the groove. The body may be wholly or in part of a filter material capable of removing particulate-phase constituents from the smoke during its passage through the element. Suitably the groove extends from the upstream end face of the body to a point short of the downstream end face, where it opens into a space separated from the downstream end by an ungrooved portion of smoke-filter material. One or more faces of the groove and/or said upstream end face may be partially or wholly sealed against penetration of smoke into the body.
Inventors
- 👤 John A. Luke
- 👤 Fred Haslam
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 05:58
CPC Classifications
A; A24; A24D; A24D3/00; A24D3/04; A24D3/043
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
96 words
A smoking-article filter element comprising a body of fibrous filter material offering a filter surface which has at least one helical groove in its peripheral surface and is closely wrapped in a material pervious to vapor-phase constituents of the smoke, whereby vapor-phase constituents are removed by diffusion thereof through said wrapping material during passage of the smoke along the said helical groove, while particulate-phase constituents are removed mechanically from the smoke passage through the said body at least a portion thereof removed by passage of smoke through the part of the body other than the groove.
Claim 2
Dependent Claim
96 words
A smoking-article filter element comprising a body of fibrous filter material offering a filter surface which has at least one helical groove in its peripheral surface and is closely wrapped in a material pervious to vapor-phase constituents of the smoke, whereby vapor-phase constituents are removed by diffusion thereof through said wrapping material during passage of the smoke along the said helical groove, while particulate-phase constituents are removed mechanically from the smoke passage through the said body at least a portion thereof removed by passage of smoke through the part of the body other than the groove.
Claim 3
Dependent Claim
38 words
A filter element according to claim 1 wherein the said helical groove terminates short of the downstream end of the element where filter material for particulate phase constituents is disposed for receiving smoke issuing from the said grooves.
Claim 4
Dependent Claim
31 words
A filter element according to claim 1 wherein the said helical groove opens at the downstream end thereof into a space located in the body short of its downstream end face.
Claim 5
Dependent Claim
20 words
A filter element according to claim 3 wherein the said space is a peripheral annular groove formed in the body.
Claim 6
Dependent Claim
31 words
A filter element according to claim 3 wherein the space is separated from the downstream end of the body by an ungrooved end portion, made of smoke-filter material, of the body.
Claim 7
Dependent Claim
35 words
A filter element according to claim 1 wherein at least one face bounding the said helical groove in the body is at least partially sealed against penetration of smoke from the groove into the body.
Claim 8
Dependent Claim
28 words
A filter element according to claim 1 wherein the upstream end face of the body is at least partially sealed against the penetration of smoke into the body.
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) | 1982-01-22 | 1982-07-24 | 1983-01-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-01-22 | 1986-07-24 | 1987-01-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-01-22 | 1990-07-24 | 1991-01-23 | $7700.00 | Window Closed / Lapsed |