← Back to Patent Explorer
US4478792A Expired / Lapsed US ⏱️ 0.0 years remaining

Colorimetric gas dosimeter

Assignee: MSA Safety Inc
•
Filing: 1983-09-16
•
Granted: 1984-10-23
•
Expires: 2003-09-16
📄 Original PDF 🌐 Google Patents 🔄 Sync Now

Abstract

Abstract A gas dosimeter comprises a stack of porous sheets, impregnated with a reagent that changes color on contact with the gas to be determined, contained in a housing which has an opening to expose one end of the stack to the atmosphere to be tested. The gas to be determined penetrates by diffusion the layers of porous sheets, causing the sheets in the stack to change color sequentially from the end of the stack exposed to the atmosphere. The degree of penetration through the layers of porous sheets is a function of dosage exposure. The housing may be transparent with each superposed sheet in the stack being larger than the adjacent underlying sheet, so that each sheet is visible through the housing endwall.

Inventors

  • 👤 Paul W. McConnaughey
  • 👤 Elmer S. McKee

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-29 10:35
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/75; G01N21/77; G01N21/78; G01N21/783; G01N2021/7796; Y; Y10; Y10S; Y10S436/00; Y10S436/902

Claims Analysis

Total Claims: 6
Claim 1
Independent Claim 92 words
A gas dosimeter comprising a stack of superposed porous sheets contained in a housing; the housing having a sidewall, a transparent endwall and means defining an opening opposite the endwall; each superposed sheet is of a larger cross-sectional area than the adjacent underlying sheet, the largest sheet being most remote from the transparent endwall and extending across the cross-sectional area of the opening; and at least each of the porous sheets, except the most remote sheet being impregnated with a reagent that changes color on contact with the gas to be determined.
Claim 2
Dependent Claim 92 words
A gas dosimeter comprising a stack of superposed porous sheets contained in a housing; the housing having a sidewall, a transparent endwall and means defining an opening opposite the endwall; each superposed sheet is of a larger cross-sectional area than the adjacent underlying sheet, the largest sheet being most remote from the transparent endwall and extending across the cross-sectional area of the opening; and at least each of the porous sheets, except the most remote sheet being impregnated with a reagent that changes color on contact with the gas to be determined.
Claim 3
Dependent Claim 12 words
A dosimeter of claim 1 in which the sheets are filter paper.
Claim 4
Dependent Claim 11 words
A dosimeter of claim 1 in which the sheets are discs.
Claim 5
Dependent Claim 14 words
A dosimeter of claim 1 in which the sheets are segments of a circle.
Claim 6
Dependent Claim 46 words
A dosimeter of claim 1 in which the housing comprises a cup-shaped body comprising the endwall and sidewall, and said opening means comprises a cover tightly engaging an outer surface of the sidewall and having an inwardly extending flange defining the opening and engaging the stack.

References Cited (Backward Citations)

US3723064A Cited
US3847552A Cited
DE2416047A1 Cited
US4076502A Cited
US4256694A Cited
US4271121A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1987-10-23 1988-04-23 1988-10-23 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1991-10-23 1992-04-23 1992-10-23 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1995-10-23 1996-04-23 1996-10-23 $7700.00 Window Closed / Lapsed

Assigned Categories & Tags

No categories assigned to this patent yet.

Assign Category Tag