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US3691818A Expired / Lapsed US ⏱️ 0.0 years remaining

Method for determination of impurities in helium gas

Assignee: United States Department of the Interior
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Filing: 1970-03-27
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Granted: 1972-09-19
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Expires: 1990-03-27
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Abstract

Abstract The helium content of a gaseous mixture is determined by comparing the partial pressure of the helium in an unknown sample directly with the pressure of highly purity helium under the same conditions. The volume percent of helium in the unknown is equal to(P1/P2) X 100, where P1 is the partial pressure of helium in the sample and P2 is the total pressure of an equal volume of high-purity helium. The partial pressure of the helium in the unknown sample is initially determined by adsorption of gases other than helium on activated charcoal and measurement of the resulting helium pressure. The total pressure of high-purity helium is then measured under the same conditions as the sample.

Inventors

  • 👤 David E Emerson

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-05 13:39
CPC Classifications
G; G01; G01N; G01N7/00; G01N7/10

Claims Analysis

Total Claims: 0
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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) 1975-09-19 1976-03-20 1976-09-19 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1979-09-19 1980-03-20 1980-09-19 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1983-09-19 1984-03-20 1984-09-19 $7700.00 Window Closed / Lapsed

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