US4348358A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Colorimetric dosimeter
Assignee: MSA Safety Inc
•
Filing: 1980-09-25
•
Granted: 1982-09-07
•
Expires: 2000-09-25
Abstract
Abstract A gas dosimeter comprises a strip substrate coated or impregnated with a color-changing reagent; the strip is disposed lengthwise in a transparent tube, one end of which is openable and is spaced by a diffusion path from one end of the strip. When the dosimeter tube is opened and exposed to the atmosphere containing detectable gas, a color change develops lengthwise of the strip dependent on the dosage exposure to the gas.
Inventors
- 👤 Elmer S. McKee
- 👤 Paul W. McConnaughey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 22:31
CPC Classifications
G; G01; G01N; G01N31/00; G01N31/22; G01N31/223; G01N31/224
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
87 words
A colorimetric gas dosimeter comprising a transparent tube having closed ends, one of said ends being openable, a detecting strip of a substrate carrying a reagent that changes color on contact with the gas to be determined, the strip being disposed lengthwise in the tube with one end of the strip spaced from the openable end of the tube by a diffusion path and with at least one side of said strip spaced apart from said tube along a substantial portion of the length of said strip.
Claim 2
Dependent Claim
87 words
A colorimetric gas dosimeter comprising a transparent tube having closed ends, one of said ends being openable, a detecting strip of a substrate carrying a reagent that changes color on contact with the gas to be determined, the strip being disposed lengthwise in the tube with one end of the strip spaced from the openable end of the tube by a diffusion path and with at least one side of said strip spaced apart from said tube along a substantial portion of the length of said strip.
Claim 3
Dependent Claim
15 words
A dosimeter of claim 1 in which the reagent is impregnated in a porous substrate.
Claim 4
Dependent Claim
12 words
A dosimeter of claim 1 in which the reagent includes a humectant.
Claim 5
Dependent Claim
16 words
A dosimeter of claim 1 for determining hydrogen sulfide in which the reagent is silver cyanide.
Claim 6
Dependent Claim
15 words
A dosimeter of claim 1 for determining nitrogen dioxide in which the reagent is o-tolidine.
Claim 7
Dependent Claim
16 words
A dosimeter of claim 3 for determining hydrogen sulfide in which the reagent is lead acetate.
Claim 8
Dependent Claim
20 words
A dosimeter of claim 3 for determining sulfur dioxide in which the reagent is phenolsulfonephthalein sodium salt and sodium carbonate.
Claim 9
Dependent Claim
15 words
A dosimeter of claim 1 for determining ammonia in which the reagent is bromophenol blue.
Claim 10
Dependent Claim
20 words
A dosimeter of claim 1 in which the inside diameter of the tube is between about 2 and 6 millimeters.
Claim 11
Dependent Claim
17 words
A dosimeter of claim 1 in which the diffusion path comprises a plug of open cell foam.
Claim 12
Dependent Claim
18 words
A dosimeter of claim 1 in which the substrate is filter paper and the reagent includes a humectant.
Claim 13
Dependent Claim
124 words
A colorimetric gas dosimeter comprising a transparent tube having closed ends, one of said ends being openable, a detecting strip of a substrate carrying a reagent that changes color on contact with the gas to be determined, the strip being disposed lengthwise in the tube with one end of the strip spaced from the openable end of the tube by a diffusion path and with at least one side of said strip spaced apart from said tube along a substantial portion of the length of said strip, a resilient grommet having an axial aperture releasably engaging the end of the tube opposite the openable end, and a second transparent tube longer than the first tube and releasably engaging the outer surface of the grommet.
Claim 14
Dependent Claim
124 words
A colorimetric gas dosimeter comprising a transparent tube having closed ends, one of said ends being openable, a detecting strip of a substrate carrying a reagent that changes color on contact with the gas to be determined, the strip being disposed lengthwise in the tube with one end of the strip spaced from the openable end of the tube by a diffusion path and with at least one side of said strip spaced apart from said tube along a substantial portion of the length of said strip, a resilient grommet having an axial aperture releasably engaging the end of the tube opposite the openable end, and a second transparent tube longer than the first tube and releasably engaging the outer surface of the grommet.
References Cited (Backward Citations)
US2606102A
Cited
US2895807A
Cited
US3620677A
Cited
US3378348A
Cited
DE1498909A1
Cited
US3701633A
Cited
US3884641A
Cited
US3985017A
Cited
US4145186A
Cited
US4159304A
Cited
US4235097A
Cited
US4269804A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-09-06 | 1986-03-08 | 1986-09-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-09-06 | 1990-03-08 | 1990-09-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-09-06 | 1994-03-08 | 1994-09-07 | $7700.00 | Window Closed / Lapsed |