US3683243A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrical hygrometers
Assignee: Moisture Control and Measurement Ltd
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Filing: 1970-10-21
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Granted: 1972-08-08
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Expires: 1990-10-21
Abstract
Abstract A sensor for an electrical hygrometer of the capacitance type comprises two metal wire electrodes one at least of which has a hygroscopic layer and the two wires are brought into intimate contact with one another to act as electrodes by twisting, wrapping or winding them together but electrically insulated from one another. The two wires may be of similar gauge and twisted to double helix form, or laid side by side and bound together, or a fine gauge one may be wound helically round a straight coarser gauge one leaving spaces between adjacent coils. The hygroscopic layer or layers may be oxidized by anodizing. A fine gauge enameled copper wire may be wound round an oxidized aluminum wire of coarser gauge. A guard surrounds the electrodes to protect the fine wires from damage.
Inventors
- 👤 Peter Rockliff
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 22:30
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/02; G01N27/22; G01N27/223; G01N27/225
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
77 words
A moisture sensor of the type exhibiting a change in electrical capacitance with a change in moisture, the sensor having two elongate electrodes, each electrode comprising a metal wire, at least one of the wires having adherent to its surface a thin film of an electrically insulative hygroscopic metal oxide, the wires being in intimate contact with one another for a substantial portion of their length, and each electrode being secured at one end to a connector.
Claim 2
Dependent Claim
77 words
A moisture sensor of the type exhibiting a change in electrical capacitance with a change in moisture, the sensor having two elongate electrodes, each electrode comprising a metal wire, at least one of the wires having adherent to its surface a thin film of an electrically insulative hygroscopic metal oxide, the wires being in intimate contact with one another for a substantial portion of their length, and each electrode being secured at one end to a connector.
Claim 3
Dependent Claim
39 words
The moisture sensor according to claim 1, wherein the wire electrodes are of pure aluminum and the hygroscopic metal oxide is an oxide of aluminum, and the two wires are twisted together in the form of a double helix.
Claim 4
Dependent Claim
73 words
The moisture sensor according to claim 1, wherein one wire is of a coarser gauge than the other wire, the coarser gauge wire having upon its surface the hygroscopic metal oxide thin film, and the surface of the finer gauge wire being covered by a thin coat of a non-hygroscopic electrical insulator, the finer gauge wire forming a helix around the coarser gauge wire with adjacent coils of the helix being spaced apart.
Claim 5
Dependent Claim
84 words
The moisture sensor according to claim 1, wherein one wire is of coarser gauge than the other wire, the coarser gauge wire being constituted of pure aluminum and having upon its surface the hygroscopic metal oxide thin film, the metal oxide being an oxide of aluminum, the finer gauge wire being of copper and having upon its surface a thin coat of enamel, and the finer gauge wire forming a helix about the other wire with adjacent coils of the helix being spaced apart.
Claim 6
Dependent Claim
67 words
The moisture sensor according to claim 1, wherein the connector comprises, an insulative sleeve in which is disposed a portion of one of the wires, the sleeve overlapping the hygroscopic film on that wire, and an electrically conductive ferrule situated over the sleeve, the other wire being electrically connected to the ferrule, and the ferrule having a flange adapted to be engaged by a current connector device.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-08-08 | 1976-02-07 | 1976-08-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-08 | 1980-02-07 | 1980-08-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-08 | 1984-02-07 | 1984-08-08 | $7700.00 | Window Closed / Lapsed |