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Patent US4438480A successfully refreshed from Google Patents.
US4438480A
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US
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Capacitive hygrometer
Assignee: Commissariat à l'Énergie Atomique et Aux Énergies Alternatives
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Filing: 1981-07-09
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Granted: 1984-03-20
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Expires: 2001-07-09
Abstract
Abstract The present invention relates to a capacitive hygrometer comprising a capacitor (1) having a dielectric material (3), whose dielectric constant varies as a function of the quantity of water absorbed. It has on one of its conductive faces numerous fissures bringing the dielectric material into direct contact with the atmosphere whose degree of humidity is to be measured. However, the electrical continuity of the fissured conductive face is maintained. Application to the measurement of the degree of humidity of the air.
Inventors
- 👤 Bernard Chambaz
- 👤 Gilles Delapierre
- 👤 Louis Destannes
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 22:37
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/02; G01N27/22; G01N27/223; G01N27/225
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
99 words
A capacitive hygrometer of the type constituted by a capacitor having a dielectric material between two conductive faces with said dielectric material having a dielectric constant which varies as a function of the quantity of water absorbed, said conductive faces being connected to means for measuring the dielectric constant, where one of the conductive faces of the capacitor, as well as the dielectric material have numerous random fissures bringing the dielectric material into direct contact with the atmosphere the relative humidity of which is capable of being measured, while the electrical continuity of the fissured conductive face is maintained.
Claim 2
Dependent Claim
99 words
A capacitive hygrometer of the type constituted by a capacitor having a dielectric material between two conductive faces with said dielectric material having a dielectric constant which varies as a function of the quantity of water absorbed, said conductive faces being connected to means for measuring the dielectric constant, where one of the conductive faces of the capacitor, as well as the dielectric material have numerous random fissures bringing the dielectric material into direct contact with the atmosphere the relative humidity of which is capable of being measured, while the electrical continuity of the fissured conductive face is maintained.
Claim 3
Dependent Claim
15 words
A capacitive hygrometer as in claim 1, wherein the dielectric material is a cellulose ester.
Claim 4
Dependent Claim
24 words
A capacitive hygrometer as in claim 1 wherein the fissured conductive face is constituted by a conductive material which is relatively insensitive to corrosion.
Claim 5
Dependent Claim
17 words
A capacitive hygrometer as in claim 3, wherein the material forming the fissured conductive base is chromium.
Claim 6
Dependent Claim
33 words
A capacitive hygrometer as in claim 3 wherein the material forming the fissured conductive face is covered by a coating of a precious metal, selected from the group consisting of platinum and gold.
Claim 7
Dependent Claim
23 words
A capacitive hygrometer as in claim 1, wherein the other conductive face of the capacitor is formed by an anodically oxidized tantalum layer.
Claim 8
Dependent Claim
65 words
A capacitor constituted by a layer of dielectric material between two conductive faces, wherein one of the conductive faces, together with the dielectric material have numerous random fissures bringing the dielectric material into contact with the atmosphere in which the capacitor is placed each fissure scoring both the dielectric material and said conductive face with the electrical continuity of the fissured conductive face being maintained.
Claim 9
Dependent Claim
65 words
A capacitor constituted by a layer of dielectric material between two conductive faces, wherein one of the conductive faces, together with the dielectric material have numerous random fissures bringing the dielectric material into contact with the atmosphere in which the capacitor is placed each fissure scoring both the dielectric material and said conductive face with the electrical continuity of the fissured conductive face being maintained.
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) | 1987-03-20 | 1987-09-19 | 1988-03-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-03-20 | 1991-09-19 | 1992-03-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-03-20 | 1995-09-19 | 1996-03-20 | $7700.00 | Window Closed / Lapsed |