Patent US4017820A successfully refreshed from Google Patents.
US4017820A
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Humidity sensor with multiple electrode layers separated by a porous monolithic ceramic dielectric structure
Assignee: Illinois Tool Works Inc
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Filing: 1976-05-13
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Granted: 1977-04-12
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Expires: 1996-05-13
Abstract
Abstract The invention concerns a humidity or moisture sensor, with a relatively thick sensitive monolithic ceramic volume. The sensitive volume is defined by a porous ceramic material with multiple electrodes buried therein in parallel planes which extend substantially entirely across two dimensions of the structure. Moisture entering the porous crystalline matrix is subjected to a high electric field giving rise to a current which is a function of the ambient moisture. By virtue of the inert ceramic surface and the buried precious metal electrodes, the device is sensitive, fast, yet electrically, chemically, thermally and mechanically stable.
Inventors
- 👤 Bernd Ross
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 12:52
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/02; G01N27/04; G01N27/12; G01N27/121
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
113 words
A multi-layered device for sensing humidity comprising a homogeneous porous monolithic dielectric structure, a plurality of electric field-producing electrode layers stacked in planes one above each other which extend substantially entirely across two dimensions of said device and which are buried into said dielectric structure with alternating ones of said electrode layers being connected to separate conductive terminals and with said electrodes being separated by said dielectric structure, which structure is formed with at least a ten percent open cell construction wherein the dielectric is comprised of: ______________________________________
Magnesium titanate (MgTiO.sub.3)
65%-75% by weight
Zinc oxide (ZnO) 10%-20% by weight
Calcium titanate (CaTiO.sub.3)
4%-7% by weight
Titanium dioxide (TiO.sub.2)
6%-9% by weight.
______________________________________
Claim 2
Dependent Claim
113 words
A multi-layered device for sensing humidity comprising a homogeneous porous monolithic dielectric structure, a plurality of electric field-producing electrode layers stacked in planes one above each other which extend substantially entirely across two dimensions of said device and which are buried into said dielectric structure with alternating ones of said electrode layers being connected to separate conductive terminals and with said electrodes being separated by said dielectric structure, which structure is formed with at least a ten percent open cell construction wherein the dielectric is comprised of: ______________________________________
Magnesium titanate (MgTiO.sub.3)
65%-75% by weight
Zinc oxide (ZnO) 10%-20% by weight
Calcium titanate (CaTiO.sub.3)
4%-7% by weight
Titanium dioxide (TiO.sub.2)
6%-9% by weight.
______________________________________
Claim 3
Dependent Claim
107 words
A multi-layered device for sensing humidity comprising a homogeneous porous monolithic dielectric structure, a plurality of electric field-producing electrode layers stacked in planes one above each other which extend substantially entirely across two dimensions of said device and which are buried into said dielectric structure with alternating ones of said electrode layers being connected to separate conductive terminals and with said electrodes being separated by said dielectric structure, which structure is formed with at least a ten percent open cell construction wherein the dielectric is comprised of cerium titanate and the firing temperature ranges from 1120° to 1220° C. with a firing time of approximately 1 hour.
Claim 4
Dependent Claim
107 words
A multi-layered device for sensing humidity comprising a homogeneous porous monolithic dielectric structure, a plurality of electric field-producing electrode layers stacked in planes one above each other which extend substantially entirely across two dimensions of said device and which are buried into said dielectric structure with alternating ones of said electrode layers being connected to separate conductive terminals and with said electrodes being separated by said dielectric structure, which structure is formed with at least a ten percent open cell construction wherein the dielectric is comprised of cerium titanate and the firing temperature ranges from 1120° to 1220° C. with a firing time of approximately 1 hour.
References Cited (Backward Citations)
US3255324A
Cited
US3916367A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-04-11 | 1980-10-11 | 1981-04-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-04-11 | 1984-10-11 | 1985-04-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-04-11 | 1988-10-11 | 1989-04-12 | $7700.00 | Window Closed / Lapsed |