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US3916367A Expired / Lapsed US ⏱️ 0.0 years remaining

Relative humidity sensor

Assignee: Honeywell Inc
•
Filing: 1974-01-22
•
Granted: 1975-10-28
•
Expires: 1994-01-22
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Abstract

Abstract An improved humidity sensing element of the electrical resistance-dependent, metal oxide type in which the metal oxide is sintered to achieve a stable cross linked porous metallurgical matrix. In the preferred embodiment, the humidity sensing element of the invention is produced by coating a dielectric blank to which an electrode system has been applied with a metal oxide selected from a group including the oxides of Group VIII, Period 4 of the Periodic Table, preferrably Fe2O3, applying a slight amount of compression to the coating and releasing the compression, heating the coated blank to a sufficient temperature and for a sufficient length of time to achieve sintering of the metal oxide and thereafter impregnating the cooled coating of the sensor with a reversably hygroscopic humectant material such as polyethylene glycol, for example.

Inventors

  • 👤 Merle E Nicholas
  • 👤 Ernest A Satren

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-04 07:40
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/02; G01N27/04; G01N27/12; G01N27/121

Claims Analysis

Total Claims: 9
Claim 1
Independent Claim 56 words
A MOISTURE SENSITIVE ELEMENT COMPRISING SPACED METAL ELECTRODES, A SINTERED ELECTRICALLY INSULATING METAL OXIDE COATING OVERLAPPING SAID ELECTRODES, SAID OXIDE HAVING A CHARACTERISTIC HUMIDITY-DEPENDENT ELECTRICAL RESISTANCE, AND WHEREIN SAID SINTERED METAL OXIDE STRUCTURE IS OF A POROUS NATURE, THE PORES THEREOF BEING IMPREGNATED WITH A REVERSIBLE HYGROSCOPIC HUMECTANT MATERIAL, AND ELECTRICAL LEADS ATTACHED TO SAID ELECTRODES.
Claim 2
Dependent Claim 56 words
A MOISTURE SENSITIVE ELEMENT COMPRISING SPACED METAL ELECTRODES, A SINTERED ELECTRICALLY INSULATING METAL OXIDE COATING OVERLAPPING SAID ELECTRODES, SAID OXIDE HAVING A CHARACTERISTIC HUMIDITY-DEPENDENT ELECTRICAL RESISTANCE, AND WHEREIN SAID SINTERED METAL OXIDE STRUCTURE IS OF A POROUS NATURE, THE PORES THEREOF BEING IMPREGNATED WITH A REVERSIBLE HYGROSCOPIC HUMECTANT MATERIAL, AND ELECTRICAL LEADS ATTACHED TO SAID ELECTRODES.
Claim 3
Dependent Claim 22 words
The moisture sensitive element of claim 1 including a substantially inert dielectric blank space member upon which said metal electrodes are applied.
Claim 4
Dependent Claim 33 words
The moisture sensitive element of claim 2, wherein said metal oxide is one selected from a group consisting of the oxides of Group VIII, Period 4 of the Periodic Table of the Elements.
Claim 5
Dependent Claim 13 words
The moisture sensitive element of claim 3 wherein said metal oxide is Fe2O3.
Claim 6
Dependent Claim 15 words
The moisture sensor of claim 1 wherein said humectant material is a stable hygroscopic polymer.
Claim 7
Dependent Claim 12 words
The moisture sensor of claim 5 wherein said humectant is Polyethylene glycol.
Claim 8
Dependent Claim 15 words
The moisture sensitive element of claim 6 including a moisture-permeable membrane superimposed over said coating.
Claim 9
Dependent Claim 15 words
The moisture sensitive element of claim 7 wherein said moisture-permeable membrane is polyvinyl alcohol sheet.

References Cited (Backward Citations)

US2543384A Cited
US3105214A Cited
US3056935A Cited
US3295088A Cited
US3686606A Cited
US3703697A Cited
US3715702A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1978-10-27 1979-04-28 1979-10-28 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1982-10-27 1983-04-28 1983-10-28 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1986-10-27 1987-04-28 1987-10-28 $7700.00 Window Closed / Lapsed

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