Patent US4780282A successfully refreshed from Google Patents.
US4780282A
Expired / Lapsed
US
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Dosimeter for measuring exposure to hydrazine and hazardous hydrazine derivatives
Assignee: Geo Centers Inc
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Filing: 1986-09-09
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Granted: 1988-10-25
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Expires: 2006-09-09
Abstract
Abstract A dosimeter for collecting vapors and gases of hydrazine and of hazardous derivatives of hydrazine such as monomethylhydrazine and 1,1-dimethylhydrazine, employs a housing with a perforated cover. Situated inside the housing is a removable disk on which is coated a solution of citric acid in methanol. The solution initially contains 20% to 30% of citric acid monohydrate dissolved in methanol and the solution is permitted to age for seven or eight days before being coated on to the disk.
Inventors
- 👤 James R. Holtzclaw
- 👤 Susan L. Rose
- 👤 Jeffrey R. Wyatt
- 👤 Chester M. Hawkins
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 11:42
CPC Classifications
G; G01; G01N; G01N31/00; G01N31/22; G01N31/223; G01N31/224; Y; Y10; Y10S; Y10S436/00; Y10S436/902; Y10T; Y10T436/00; Y10T436/17
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
97 words
In a dosimeter for collecting vapors and gases of hydrazine and hazardous hydrazine derivatives, where the dosimeter comprises a case with a shallow cavity therein, the case having a perforate cover in which there are a plurality of holes providing entry for the vapors and gases into the shallow cavity, the improvement comprising a removable substrate disposed in the shallow cavity in a manner providing a space in the cavity between the cover and a surface of the substrate, and a coating of a solution of citric acid in methanol disposed on said surface of the substrate.
Claim 2
Dependent Claim
97 words
In a dosimeter for collecting vapors and gases of hydrazine and hazardous hydrazine derivatives, where the dosimeter comprises a case with a shallow cavity therein, the case having a perforate cover in which there are a plurality of holes providing entry for the vapors and gases into the shallow cavity, the improvement comprising a removable substrate disposed in the shallow cavity in a manner providing a space in the cavity between the cover and a surface of the substrate, and a coating of a solution of citric acid in methanol disposed on said surface of the substrate.
Claim 3
Dependent Claim
13 words
The improvement according to claim 1, wherein the substrate is a polyester sheet.
Claim 4
Dependent Claim
20 words
The improvement according to claim 1, wherein the coating initially contains citric acid or a hydrate thereof dissolved in methanol.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-10-25 | 1992-04-25 | 1992-10-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-10-25 | 1996-04-25 | 1996-10-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-10-25 | 2000-04-25 | 2000-10-25 | $7700.00 | Window Closed / Lapsed |