US3636768A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Infrared hygrometers
Assignee: Thales SA
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Filing: 1970-06-18
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Granted: 1972-01-25
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Expires: 1990-06-18
Abstract
Abstract An infrared hygrometer comprising an infrared source supplying two identical infrared beams chopped alternately. One of the beams passes through an enclosure containing dry air at the atmospheric pressure and the other beam passes through a second enclosure in which the air whose humidity is to be measured circulates. Two auxiliary cavities in which this air also circulates are located in the path respectively of the two beams and have windows for the passage of these beams. The cavity which is disposed in the path of the beam passing through the second enclosure communicates with this enclosure by an opening through which this beam passes, so that the number of faces of windows in contact with the humid air is identical in the paths of the two beams. An infrared detector receives the two beams and its output signal is applied to measuring circuits with synchronous detection.
Inventors
- 👤 Claude Tinet
- 👤 Pierre Misme
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 21:49
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/17; G01N21/25; G01N21/31; G01N21/35; G01N21/3504
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
268 words
An infrared hygrometer, for measuring the humidity of a given air, comprising: an infrared source; first means associated with said source for supplying first and second identical infrared beams and for chopping said beams alternately; a first enclosure containing dry air and located in the path of said first beam, said enclosure having an entrance and an exit window for said first beam; a second enclosure, in which said given air circulates and which is located in the path of said second beam, said second enclosure having at least one window for the passage of said second beam; first and second cavities located respectively in the path of said first and second beams and in which said given air circulates, said first and second cavities being so selected that the lengths of the paths of said first and second beams respectively in said first and second cavities are identical, Each of said cavities comprising at least one window for the passage of the beam in the path of which said lastmentioned window is located, all of said windows being identical, and the numbers of windows in contact with said given air in said cavities and in said second enclosure being so selected that the number of faces of windows in contact with said given air respectively in the path of said first beam and in the path of said second beam are identical; detector means for detecting said first and second beams after their passage through said enclosures and said cavities; and measuring circuits connected to said detector means and to said first means for measuring said humidity.
Claim 2
Dependent Claim
268 words
An infrared hygrometer, for measuring the humidity of a given air, comprising: an infrared source; first means associated with said source for supplying first and second identical infrared beams and for chopping said beams alternately; a first enclosure containing dry air and located in the path of said first beam, said enclosure having an entrance and an exit window for said first beam; a second enclosure, in which said given air circulates and which is located in the path of said second beam, said second enclosure having at least one window for the passage of said second beam; first and second cavities located respectively in the path of said first and second beams and in which said given air circulates, said first and second cavities being so selected that the lengths of the paths of said first and second beams respectively in said first and second cavities are identical, Each of said cavities comprising at least one window for the passage of the beam in the path of which said lastmentioned window is located, all of said windows being identical, and the numbers of windows in contact with said given air in said cavities and in said second enclosure being so selected that the number of faces of windows in contact with said given air respectively in the path of said first beam and in the path of said second beam are identical; detector means for detecting said first and second beams after their passage through said enclosures and said cavities; and measuring circuits connected to said detector means and to said first means for measuring said humidity.
Claim 3
Dependent Claim
68 words
A hygrometer as claimed in claim 1, wherein said first cavity comprises an entrance window and an exit window for said first beam, said second enclosure and said second cavity comprise each one window for the passage of said second beam and an opening for direct communication of said second cavity with said second enclosure and for the passage of said second beam and of said given air.
Claim 4
Dependent Claim
19 words
A hygrometer as claimed in claim 1, wherein said first and second cavities are parts of a single cavity.
Claim 5
Dependent Claim
19 words
A hygrometer as claimed in claim 2, wherein said first and second cavities are parts of a single cavity.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-01-24 | 1975-07-26 | 1976-01-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-24 | 1979-07-26 | 1980-01-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-24 | 1983-07-26 | 1984-01-25 | $7700.00 | Window Closed / Lapsed |