Patent US4444574A successfully refreshed from Google Patents.
US4444574A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Partially-carbonized polyacrylonitrile filter
Assignee: Individual
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Filing: 1982-10-06
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Granted: 1984-04-24
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Expires: 2002-10-06
Abstract
Abstract A filter for extracting solids and liquids from gaseous combustion exhausts comprises a textile filter element formed of polyacrylonitrile fibers oxidized by careful heat treatment and comprising approximately 61% carbon after treatment. The filter may be woven, knitted or formed as a batting of randomly-oriented fibers. Abrasion resistant coatings and lubricants for the fibers are disclosed. The filter material is especially useful as a filter bag.
Inventors
- 👤 George Tradewell
- 👤 W. Novis Smith
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 16:30
CPC Classifications
B; B01; B01D; B01D39/00; B01D39/14; B01D39/20; B01D39/2055; B01D39/2065; B01D39/08; B01D39/083; B01D46/00; B01D46/02; D; D01; D01F; D01F9/00; D01F9/08; D01F9/12; D01F9/14; D01F9/20; D01F9/21; D01F9/22; D01F9/225; D06; D06M; D06M11/00; D06M11/32; D06M11/34; B01D2239/00; B01D2239/04; B01D2239/0457; B01D2239/0471; B01D2239/0478; B01D2239/06; B01D2239/0604; B01D2239/0627; B01D2239/064; B01D2239/0645; B01D2239/12; B01D2239/1233; Y; Y10; Y10S; Y10S55/00; Y10S55/30; Y10T; Y10T428/00; Y10T428/29; Y10T428/2913; Y10T428/2918; Y10T428/30
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
50 words
A method for filtering pollutants from combustion exhaust, comprising the steps of: placing a filter bag of polyacrylonitrile fibers, oxidized and carbonized to approximately 61% carbon, in a path defined by the exhaust, the exhaust passing through the filter bag, and periodically removing accumulation of pollutants from the filter bag.
Claim 2
Independent Claim
50 words
A method for filtering pollutants from combustion exhaust, comprising the steps of: placing a filter bag of polyacrylonitrile fibers, oxidized and carbonized to approximately 61% carbon, in a path defined by the exhaust, the exhaust passing through the filter bag, and periodically removing accumulation of pollutants from the filter bag.
Claim 3
Dependent Claim
38 words
The method of claim 1, wherein the filter bag is disposed at a point in the path defined by the dew point of a liquid pollutant contained in the exhaust, whereby the liquid condenses on the filter bag.
Claim 4
Dependent Claim
30 words
A filter for extracting solids and liquids from gaseous combustion exhaust, comprising a textile filter member formed of polyacrylonitrile fibers, partially and evenly oxidized to approximately 61% carbon by weight.
Claim 5
Dependent Claim
30 words
A filter for extracting solids and liquids from gaseous combustion exhaust, comprising a textile filter member formed of polyacrylonitrile fibers, partially and evenly oxidized to approximately 61% carbon by weight.
Claim 6
Dependent Claim
11 words
The filter of claim 1, wherein said filter member is knitted.
Claim 7
Dependent Claim
18 words
The filter of claim 1, wherein said filter member is formed from a non-woven batt of randomly-oriented fibers.
Claim 8
Dependent Claim
20 words
The filter of claim 1, further comprising an abrasion resistant coating chosen from the group silicone, melamine and polyimide resins.
Claim 9
Dependent Claim
18 words
The filter of claim 1, wherein said filter member is formed in the shape of a filter bag.
Claim 10
Dependent Claim
15 words
The filter of claim 3, wherein said textile filter member is formed of woven fibers.
Claim 11
Dependent Claim
35 words
The filter member of claim 8, wherein said filter member is woven in a basket weave from yarn strands in a plurality of plys, the plys having filaments approximately 8 to 10 micrometers in diameter.
Claim 12
Dependent Claim
11 words
The filter of claim 8, wherein said woven fibers are spun.
Claim 13
Dependent Claim
12 words
The filter of claim 8, wherein said woven fibers are continuous filament.
Claim 14
Dependent Claim
15 words
The filter of claim 3, further comprising aramid filaments blended into the oxidized polyacrylonitrile fibers.
Claim 15
Dependent Claim
15 words
The filter of claim 3, further comprising aramid fibers woven together with oxidized polyacrylonitrile fibers.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-04-24 | 1987-10-24 | 1988-04-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-04-24 | 1991-10-24 | 1992-04-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-04-24 | 1995-10-24 | 1996-04-24 | $7700.00 | Window Closed / Lapsed |