Patent US4154586A successfully refreshed from Google Patents.
US4154586A
Expired / Lapsed
US
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Respirator cartridge end-of-service lift indicator system and method of making
Assignee: Cabot Safety Intermediate LLC
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Filing: 1978-01-13
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Granted: 1979-05-15
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Expires: 1998-01-13
Abstract
Abstract Providing visual means for indicating when vapor/gas respirator cartridges have exhausted their capacity to provide respiratory protection at or below a hazardous concentration level. In combination with a vapor/gas indicator adapted to undergo a change in color with contact by an organic vapor or gas, there is provided a catalytic agent for enhancing activation and reaction of the indicator agent.
Inventors
- 👤 John A. Jones
- 👤 Adolfo V. Ayes
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 20:52
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/75; G01N21/77; G01N21/78; A; A62; A62B; A62B18/00; A62B18/08; A62B18/088; G01N31/00; G01N31/22; G01N31/223; G01N31/224; Y; Y10; Y10S; Y10S55/00; Y10S55/33; Y10S55/34
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
105 words
In a respirator cartridge having a shell within which there is supported a gas/vapor sorbent and an indicator agent selected from the group consisting of sodium dichromate and potassium dichromate characterized to undergo a change in color concomitant with exposure to concentrations of organic vapors and gases which are below a threshold limit known to be safe to inhale, the improvement comprising: catalytic/oxidizing means for rendering a gas/vapor entering the cartridge and passing through said means more readily detected by said indicator agent than with non-use of said means, said catalytic/oxidizing means being located adjacent to an upstream of said indicator agent in said cartridge.
Claim 2
Dependent Claim
105 words
In a respirator cartridge having a shell within which there is supported a gas/vapor sorbent and an indicator agent selected from the group consisting of sodium dichromate and potassium dichromate characterized to undergo a change in color concomitant with exposure to concentrations of organic vapors and gases which are below a threshold limit known to be safe to inhale, the improvement comprising: catalytic/oxidizing means for rendering a gas/vapor entering the cartridge and passing through said means more readily detected by said indicator agent than with non-use of said means, said catalytic/oxidizing means being located adjacent to an upstream of said indicator agent in said cartridge.
Claim 3
Dependent Claim
13 words
The improvement according to claim 1 wherein said catalytic/oxidizing means includes a carrier.
Claim 4
Dependent Claim
12 words
The improvement according to claim 2 wherein said carrier is activated carbon.
Claim 5
Dependent Claim
12 words
The improvement according to claim 2 wherein said carrier is silica gel.
Claim 6
Dependent Claim
83 words
The improvement according to claim 1 wherein said catalytic/oxidizing means is formulated of the approximate related proportions of ingredients of 50 grams activated carbon to which is added an impregnating solution of 200 ml H 2 O, 30 (±20) grams Na 2 Cr 2 O 7 and 30 (+30, -15) ml concentrated H 2 SO 4 ; said solution being reduced by said carbon and excess thereof decanted from said carbon with the residue allowed to dry in place as said catalytic/oxidizing means.
Claim 7
Dependent Claim
27 words
The improvement according to claim 5 wherein said decanted reduced sodium dichromate solution is applied to granular silica gel and dried thereinplace to provide said catalytic/oxidizing means.
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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) | 1982-05-14 | 1982-11-13 | 1983-05-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-05-14 | 1986-11-13 | 1987-05-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-05-14 | 1990-11-13 | 1991-05-15 | $7700.00 | Window Closed / Lapsed |