US3658069A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Filter for reducing the level of carbon monoxide in tobacco smoke
Assignee: SRI International Inc
•
Filing: 1970-02-17
•
Granted: 1972-04-25
•
Expires: 1990-02-17
Abstract
Abstract A large proportion of the carbon monoxide present in tobacco smoke can be removed by use of a composite filter having an activated charcoal component and a molecular sieve component which is positioned downstream from the charcoal.
Inventors
- 👤 Henry Wise
- 👤 Larry L Holbrook
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 14:41
CPC Classifications
A; A24; A24D; A24D3/00; A24D3/06; A24D3/16; A24D3/166; A24D3/163
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
28 words
A cigarette as recited in claim 1 wherein the molecular sieve material is selected from the group consisting of those designated as 4A, 5A and 13X molecular sieves.
Claim 2
Dependent Claim
46 words
A cigarette as recited in claim 1 wherein the filter element comprises a cellulosic plug positioned adjacent the tobacco, then the activated charcoal, then a second cellulosic plug, then the molecular sieve material, and finally, at the end of the filter element, a third cellulosic plug.
Claim 3
Dependent Claim
49 words
A cigarette as recited in claim 1 wherein the filter element comprises a convoluted creped paper plug positioned next to the tobacco column and having the activated charcoal dispersed in its interstices, then the molecular sieve material, and finally, at the end of the filter element, a cellulosic plug.
Claim 4
Dependent Claim
25 words
A cigarette as recited in claim 4 wherein a cellulosic plug is interposed between the creped paper plug and the body of molecular sieve material.
Claim 5
Dependent Claim
49 words
A cigarette as recited in claim 1 wherein the filter element comprises a convoluted creped paper plug positioned next to the tobacco column and having the activated charcoal dispersed in its interstices, and then a second convoluted creped paper plug having the molecular sieve material dispersed in its interstices.
Claim 6
Dependent Claim
26 words
A cigarette as recited in claim 6 wherein the second creped paper plug is followed by a cellulosic plug at the end of the filter element.
References Cited (Backward Citations)
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Cited
US2882243A
Cited
US3128680A
Cited
US3251365A
Cited
US3327718A
Cited
US3368566A
Cited
US3347245A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-04-25 | 1975-10-25 | 1976-04-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-04-25 | 1979-10-25 | 1980-04-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-04-25 | 1983-10-25 | 1984-04-25 | $7700.00 | Window Closed / Lapsed |