Patent EP0168966A2 successfully refreshed from Google Patents.
Patent US4259287A successfully refreshed from Google Patents.
US4259287A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Testing tube construction for measuring sodium hydroxide and/or calcium oxide
Assignee: Draegerwerk AG and Co KGaA
•
Filing: 1979-10-25
•
Granted: 1981-03-31
•
Expires: 1999-10-25
Abstract
Abstract A testing tube for measuring sodium hydroxide and/or calcium oxide aerosols, comprises, a glass tube having breakoff points at each end to open at each end and containing a front layer of a substrate material impregnated with ammonium chloride and a following indicating layer of a substrate material impregnated with an acid and bromphenol blue.
Inventors
- 👤 Kurt Leichnitz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 12:52
CPC Classifications
G; G01; G01N; G01N31/00; G01N31/22; G01N31/223; Y; Y10; Y10T; Y10T436/00; Y10T436/15
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
168 words
A testing tube, for quantitatively measuring sodium hydroxide and/or calcium oxide aerosols, comprising, a tube having an opening at each end for the flow of a gas to be tested therethrough, a front layer of material disposed in said tube comprising a substrate material impregnated with ammonium chloride and an indicating layer disposed behind the substrate material in respect to the direction of gas flow and comprising a substrate material impregnated with acid and bromphenol blue, said tube being made of glass and incuding breaking tips at each end which may be severed to open the tube, whereby stoichiometric quantities of the sodium hydroxide and/or calcium oxide of the gas to be tested react with the ammonium choride in the front layer to produce stoichiometric quantities of ammonia, the ammonia reacting with the acid in the presence of the bromphenol blue to indicate the stoichiometric and quantitative amount of ammonia produced which corresponds to the amount of sodium hydroxide and/or calcium oxide in the gas to be tested.
Claim 2
Dependent Claim
168 words
A testing tube, for quantitatively measuring sodium hydroxide and/or calcium oxide aerosols, comprising, a tube having an opening at each end for the flow of a gas to be tested therethrough, a front layer of material disposed in said tube comprising a substrate material impregnated with ammonium chloride and an indicating layer disposed behind the substrate material in respect to the direction of gas flow and comprising a substrate material impregnated with acid and bromphenol blue, said tube being made of glass and incuding breaking tips at each end which may be severed to open the tube, whereby stoichiometric quantities of the sodium hydroxide and/or calcium oxide of the gas to be tested react with the ammonium choride in the front layer to produce stoichiometric quantities of ammonia, the ammonia reacting with the acid in the presence of the bromphenol blue to indicate the stoichiometric and quantitative amount of ammonia produced which corresponds to the amount of sodium hydroxide and/or calcium oxide in the gas to be tested.
Claim 3
Dependent Claim
30 words
A testing tube as claimed in claim 1, wherein said front layer comprises a substrate material of silica gel or glass fibres, said substrate material being impregnated with ammonium chloride.
Claim 4
Dependent Claim
18 words
A testing tube, as claimed in claim 1, wherein said indicating layer comprises hydrochloric acid and bromphenol blue.
References Cited (Backward Citations)
US3131030A
Cited
US3312527A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-03-30 | 1984-09-29 | 1985-03-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-03-30 | 1988-09-29 | 1989-03-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-03-30 | 1992-09-29 | 1993-03-31 | $7700.00 | Window Closed / Lapsed |