Patent US4383956A successfully refreshed from Google Patents.
US4383956A
Expired / Lapsed
US
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Method of a single element complete air filtering structure for a respirator filter cartridge
Assignee: American Optical Corp
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Filing: 1981-01-30
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Granted: 1983-05-17
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Expires: 2001-01-30
Abstract
Abstract A respirator filter formed of a cast polymeric matrix having a controlled porosity and inclusion of toxic gas absorbing and/or neutralizing chemicals. The chemicals are introduced into the casting precursor or added after polymerization, e.g. by imbibition with a solvent carrier and deposition by solvent evaporation.
Inventors
- 👤 George T. Croft
- 👤 Richard J. Hovey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 12:40
CPC Classifications
B; B01; B01J; B01J20/00; B01J20/28; B01J20/28014; B01J20/28026; A; A62; A62B; A62B19/00; A62D; A62D9/00; B01D; B01D53/00; B01D53/02; B01J20/28042; B01J20/28045; B01J20/28054; B01J20/28095; B01J20/28097; B29; B29C; B29C67/00; B29C67/20; B29C67/202; C; C08; C08J; C08J9/00; C08J9/26
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
83 words
The method of making a single element complete air filtering structure for a respirator filter cartridge comprising the steps of: preparing a casting precursor of polymeric material and including in said casting precursor a leachable additive; casting said precursor to a shape and size desired of said single element structure; leaching said leachable additive from said material to form an open pore matrix structure; and introducing a toxic gas neutralizing agent into said matrix structure prior to or subsequent to casting and leaching.
Claim 2
Independent Claim
83 words
The method of making a single element complete air filtering structure for a respirator filter cartridge comprising the steps of: preparing a casting precursor of polymeric material and including in said casting precursor a leachable additive; casting said precursor to a shape and size desired of said single element structure; leaching said leachable additive from said material to form an open pore matrix structure; and introducing a toxic gas neutralizing agent into said matrix structure prior to or subsequent to casting and leaching.
Claim 3
Dependent Claim
17 words
The method according to claim 1 wherein said gas neutralizing agent is introduced into said casting precursor.
Claim 4
Dependent Claim
32 words
The method of claim 1 wherein said gas neutralizing agent is deposited in said open pores of said filter structure subsequent to said casting and leaching of said matrix structure forming material.
Claim 5
Dependent Claim
14 words
The method of claim 2 wherein said gas neutralizing means is in particle form.
Claim 6
Dependent Claim
35 words
The method according to claim 3 wherein said gas neutralizing agent is initially in solution with a solvent and caused to become imbibed by said porous matrix for deposit therein by evaporation of said solvent.
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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) | 1986-05-16 | 1986-11-15 | 1987-05-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-05-16 | 1990-11-15 | 1991-05-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-05-16 | 1994-11-15 | 1995-05-17 | $7700.00 | Window Closed / Lapsed |