Patent US4279773A successfully refreshed from Google Patents.
US4279773A
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US
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Composition useful for detecting H2 S
Assignee: AT&T Inc
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Filing: 1979-08-15
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Granted: 1981-07-21
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Expires: 1999-08-15
Abstract
Abstract An indicator device useful for detecting H 2 S is disclosed. This detector utilizes a polymer having a permeation constant of at least 5×10 -9 cm 3 H 2 S·cm thickness/(cm 2 area·sec·cm Hg) with an incorporated lead containing compound at concentration levels of at least 10 weight percent. These compositions are useful for detecting hydrogen sulfide in concentrations as low as approximately 10 parts per billion by volume, or concentrations of approximately 1 part per million in relatively short periods, e.g., five minutes, and are utilizable for quantitative measurements of H 2 S concentration.
Inventors
- 👤 John P. Franey
- 👤 Thomas E. Graedel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 10:25
CPC Classifications
G; G01; G01N; G01N31/00; G01N31/22; G01N31/223; G01N31/224; G01N33/00; G01N33/0004; G01N33/0009; G01N33/0027; G01N33/0036; G01N33/0044; Y; Y10; Y10T; Y10T436/00; Y10T436/18; Y10T436/182; Y10T436/184
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
108 words
A detection apparatus suitable for quantitatively detecting H 2 S comprising a polymer having incorporated a lead containing additive characterized in that said lead containing additive reacts with H 2 S, and is present in a quantity of at least 10 weight percent of said polymer wherein said quantity is a quantity which would be sufficient to avoid more than 1×10 -5 moles of HCl evolution in five hours for each gram of a PVC sample utilizing said additive in said quantity, and wherein the permeation constant at 25 degrees C. of said polymer is at least 5×10 -9 cm 3 H 2 S·cm thickness/(cm 2 area·sec·cm Hg).
Claim 2
Dependent Claim
108 words
A detection apparatus suitable for quantitatively detecting H 2 S comprising a polymer having incorporated a lead containing additive characterized in that said lead containing additive reacts with H 2 S, and is present in a quantity of at least 10 weight percent of said polymer wherein said quantity is a quantity which would be sufficient to avoid more than 1×10 -5 moles of HCl evolution in five hours for each gram of a PVC sample utilizing said additive in said quantity, and wherein the permeation constant at 25 degrees C. of said polymer is at least 5×10 -9 cm 3 H 2 S·cm thickness/(cm 2 area·sec·cm Hg).
Claim 3
Dependent Claim
15 words
The detection apparatus of claim 1 wherein said lead containing additive is tribasic lead sulfate.
Claim 4
Dependent Claim
11 words
The detection apparatus of claim 2 wherein said polymer is polyvinylchloride.
Claim 5
Dependent Claim
11 words
The detection apparatus of claim 1 wherein said polymer is polyvinylchloride.
Claim 6
Dependent Claim
18 words
The detection apparatus of claim 1 wherein said weight percent is in the range 10 to 20 percent.
References Cited (Backward Citations)
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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) | 1984-07-20 | 1985-01-19 | 1985-07-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-07-20 | 1989-01-19 | 1989-07-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-07-20 | 1993-01-19 | 1993-07-21 | $7700.00 | Window Closed / Lapsed |