US3895271A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Moisture sensors
Assignee: Molecular Controls Ltd
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Filing: 1972-05-24
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Granted: 1975-07-15
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Expires: 1992-05-24
Abstract
Abstract A moisture sensor for a hygrometer and a method of manufacturing such a sensor. The method comprises flattening part of a length of aluminium wire between two elements at least one of which has a smooth flat surface, to form an aluminium strip having at least one smooth flat surface, causing oxidation of at least the smooth flat surface and providing a layer of a second metal over at least part of the oxidized surface, the second metal being preferably a noble metal and securely anchored to the layer by a baking process. After baking the sensor may be boiled in a solution capable of loading the oxide layer with heavy metal ions.
Inventors
- 👤 Tibor Dudas
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 20:24
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/02; G01N27/22; G01N27/223; G01N27/225; Y; Y10; Y10T; Y10T29/00; Y10T29/43
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
91 words
A method of manufacturing a moisture sensor for a hygrometer, the method comprising flattening part of a length of aluminium wire between two elements, at least one of which has a smooth flat surface, to form an aluminium strip having at least one smooth flat surface, oxidizing at least said smooth flat surface in an alkaline solution and providing a layer of a second metal over at least part of the oxidized surface, wherein the alkaline solution is selected from the group consisting of sodium hydroxide solution and potassium hydroxide solution.
Claim 2
Independent Claim
91 words
A method of manufacturing a moisture sensor for a hygrometer, the method comprising flattening part of a length of aluminium wire between two elements, at least one of which has a smooth flat surface, to form an aluminium strip having at least one smooth flat surface, oxidizing at least said smooth flat surface in an alkaline solution and providing a layer of a second metal over at least part of the oxidized surface, wherein the alkaline solution is selected from the group consisting of sodium hydroxide solution and potassium hydroxide solution.
Claim 3
Independent Claim
105 words
A method of manufacturing a moisture sensor for a hygrometer, the method comprising flattening part of a length of aluminium wire between two elements, at least one of which has a smooth flat surface, to form an aluminium strip having at least one smooth flat surface, oxidizing at least said smooth flat surface in an alkaline solution and providing a layer of a second metal over at least part of the oxidized surface, in which the second metal is silver and covers less than 25% of the area of the oxidized flat surface, the silver being applied by painting colloidal silver diluted with amyl acetate.
Claim 4
Independent Claim
105 words
A method of manufacturing a moisture sensor for a hygrometer, the method comprising flattening part of a length of aluminium wire between two elements, at least one of which has a smooth flat surface, to form an aluminium strip having at least one smooth flat surface, oxidizing at least said smooth flat surface in an alkaline solution and providing a layer of a second metal over at least part of the oxidized surface, in which the second metal is silver and covers less than 25% of the area of the oxidized flat surface, the silver being applied by painting colloidal silver diluted with amyl acetate.
Claim 5
Independent Claim
100 words
A method of manufacturing a moisture sensor for a hygrometer, the method comprising flattening part of a length of aluminium wire between two elements, at least one of which has a smooth flat surface, to form an aluminium strip having at least one smooth flat surface, oxidizing at least said smooth flat surface in an alkaline solution and providing a layer of a second metal over at least part of the oxidized surface, in which after provision of the second metal layer the sensor is baked for from 4 to 6 minutes at a temperature of from 140* to 160*C.
Claim 6
Independent Claim
100 words
A method of manufacturing a moisture sensor for a hygrometer, the method comprising flattening part of a length of aluminium wire between two elements, at least one of which has a smooth flat surface, to form an aluminium strip having at least one smooth flat surface, oxidizing at least said smooth flat surface in an alkaline solution and providing a layer of a second metal over at least part of the oxidized surface, in which after provision of the second metal layer the sensor is baked for from 4 to 6 minutes at a temperature of from 140* to 160*C.
Claim 7
Independent Claim
98 words
A method of manufacturing a moisture sensor for a hygrometer, the method comprising flattening part of a length of aluminium wire between two elements, at least one of which has a smooth flat surface, to form an aluminium strip having at least one smooth flat surface, oxidizing at least said smooth flat surface in an alkaline solution aNd providing a layer of a second metal over at least part of the oxidized surface, in which after provision of the second metal layer the sensor is boiled for from 25 to 35 seconds in a solution of sodium tungstate.
Claim 8
Independent Claim
98 words
A method of manufacturing a moisture sensor for a hygrometer, the method comprising flattening part of a length of aluminium wire between two elements, at least one of which has a smooth flat surface, to form an aluminium strip having at least one smooth flat surface, oxidizing at least said smooth flat surface in an alkaline solution aNd providing a layer of a second metal over at least part of the oxidized surface, in which after provision of the second metal layer the sensor is boiled for from 25 to 35 seconds in a solution of sodium tungstate.
Claim 9
Independent Claim
108 words
A method of manufacturing a moisture sensor for a hygrometer, the method comprising flattening part of a length of aluminium wire between two elements, at least one of which has a smooth flat surface, to form an aluminium strip having at least one smooth flat surface, oxidizing at least said smooth flat surface in an alkaline solution and providing a layer of a second metal over at least part of the oxidized surface, in which the coated and finished aluminium strip is mounted on a holder fitted with a coaxial coupling, the two parts of which are electrically connected respectively to the aluminium and to the second metal.
Claim 10
Independent Claim
108 words
A method of manufacturing a moisture sensor for a hygrometer, the method comprising flattening part of a length of aluminium wire between two elements, at least one of which has a smooth flat surface, to form an aluminium strip having at least one smooth flat surface, oxidizing at least said smooth flat surface in an alkaline solution and providing a layer of a second metal over at least part of the oxidized surface, in which the coated and finished aluminium strip is mounted on a holder fitted with a coaxial coupling, the two parts of which are electrically connected respectively to the aluminium and to the second metal.
Claim 11
Dependent Claim
34 words
A method according to claim 5 in which after mounting the coaxial coupling is connected across an A.C. supply of from 6 to 10 volts and 1.0 to 1.4 amp. for a short period.
Claim 12
Dependent Claim
66 words
A MOISTURE SENSOR COMPRISING A STRIP OF ALUMINIUM HAVING AT LEAST ONE SMOOTH, FLAT SURFACE, A LAYER OF ALUMINIUM OXIDE ON SAID SURFACE, SAID LAYER BEING FORMED BY TREATING SAID SURFACE IN AN ALKALINE SOLUTION, AND A LAYER OF A SECOND METAL OVER PART OF THE OXIDE LAYER, WHEREIN THE ALKALINE SOLUTION IS SELECTED FROM THE GROUP CONSISTING OF SODIUM HYDROXIDE SOLUTION AND POTASSIUM HYDROXIDE SOLUTION.
Claim 13
Dependent Claim
66 words
A MOISTURE SENSOR COMPRISING A STRIP OF ALUMINIUM HAVING AT LEAST ONE SMOOTH, FLAT SURFACE, A LAYER OF ALUMINIUM OXIDE ON SAID SURFACE, SAID LAYER BEING FORMED BY TREATING SAID SURFACE IN AN ALKALINE SOLUTION, AND A LAYER OF A SECOND METAL OVER PART OF THE OXIDE LAYER, WHEREIN THE ALKALINE SOLUTION IS SELECTED FROM THE GROUP CONSISTING OF SODIUM HYDROXIDE SOLUTION AND POTASSIUM HYDROXIDE SOLUTION.
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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) | 1978-07-14 | 1979-01-13 | 1979-07-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-07-14 | 1983-01-13 | 1983-07-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-07-14 | 1987-01-13 | 1987-07-15 | $7700.00 | Window Closed / Lapsed |