US4523142A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for sensing dew and frost
Assignee: Murata Manufacturing Co Ltd
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Filing: 1982-09-27
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Granted: 1985-06-11
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Expires: 2002-09-27
Abstract
Abstract An apparatus for sensing dew and frost, comprising a sensing portion which includes a substrate (1) having less permittivity than ice and includes a pair of electrodes (2, 3) arranged to touch the substrate (1) and further includes a resistive film (4) on the substrate (1) covering the pair of electrodes (2, 3), the impedance between the pair of electrodes (2, 3) changing in three states, or dry, bedewed and frosted states.
Inventors
- 👤 Michihiro Murata
- 👤 Akira Kumada
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 02:00
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/02; G01N27/04; G01N27/12; G01N27/121; G01N27/122
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
157 words
An apparatus for sensing dry, bedewed and frosted states, comprising: a sensing element including a base material having a permeativity which is less than the permeativity of ice and a pair of electrodes coupled to said base material at spaced locations thereof, the impedance of said sensing element as measured across said electrodes varying as a function of whether said sensing element is in the dry, bedewed or frosted states, said impedance being at a maximum value when said sensing element is in the dry state, said impedance being at a middle value lower than said maximum value when said sensing element is in the frosted state, said impedance being at a minimum value lower than said maximum and minimum values when said sensing element is in the bedewed state; and means for measuring the impedance between said electrodes and generating electric signals indicative of whether said sensing element is in the dry, bedewed or frosted state.
Claim 2
Independent Claim
157 words
An apparatus for sensing dry, bedewed and frosted states, comprising: a sensing element including a base material having a permeativity which is less than the permeativity of ice and a pair of electrodes coupled to said base material at spaced locations thereof, the impedance of said sensing element as measured across said electrodes varying as a function of whether said sensing element is in the dry, bedewed or frosted states, said impedance being at a maximum value when said sensing element is in the dry state, said impedance being at a middle value lower than said maximum value when said sensing element is in the frosted state, said impedance being at a minimum value lower than said maximum and minimum values when said sensing element is in the bedewed state; and means for measuring the impedance between said electrodes and generating electric signals indicative of whether said sensing element is in the dry, bedewed or frosted state.
Claim 3
Dependent Claim
260 words
An apparatus in accordance with claim 1, wherein said impedance measuring means comprises: first reference level setting means for setting a first reference level which resides between said middle value and the minimum value of said impedance between said electrodes; second reference level setting means for setting a second reference level which resides between said middle value and the maximum value of said impedance between said electrodes; first comparing means for comparing said first reference level provided by said first reference level setting means with said impedance between the electrodes of said sensing element; second comparing means for comparing said second reference level provided by said second reference level setting means with the impedance between the electrodes of said sensing element; and determining means for determining that the dry state exists when said first comparing means indicates that the impedance between said electrodes is higher than said first reference level and said second comparing means indicates that the impedance between said electrodes is higher than said second reference level, for determining that the frosted state exists when said first comparing means indicates that the impedance between said electrodes is higher than said first reference level and said second comparing means indicates that the impedance between said electrodes is lower than said second reference level, and for determining that the bedewed state exists when said first comparing means indicates that the impedance between said electrodes is lower than said first reference level and said second comparing means indicates that the impedance between said electrodes is lower than said second reference level.
Claim 4
Dependent Claim
26 words
An apparatus in accordance with claim 1 or 2, wherein said base material includes a ceramic substrate, and said electrodes are arranged on said ceramic substrate.
Claim 5
Dependent Claim
47 words
An apparatus in accordance with claim 1 or 2, wherein said base material includes a resistive film arranged on an isolating substrate, and wherein said electrodes are arranged on said isolating substrate such that at least a part of said electrodes is covered with said resistive film.
Claim 6
Dependent Claim
73 words
An apparatus in accordance with claim 1 or 2, wherein the impedance between said electrodes is: defined in said dry state primarily as a function of said resistance of said base material; defined in said frosted state primarily as a function of the permittivity of ice forming frost on said base material; and defined in said bedewed state primarily as a function of an ionic conduction through dew formed on said base material.
Claim 7
Dependent Claim
22 words
An apparatus in accordance with claim 2, wherein said first comparing means and said second comparing means each include an operation amplifier.
Claim 8
Dependent Claim
15 words
An apparatus in accordance with claim 2, wherein said determining means includes a gating means.
Claim 9
Dependent Claim
71 words
An apparatus in accordance with claim 3, wherein the impedance between said electrodes is: defined in said dry state primarily as a function of said resistance of said base material; defined in said frosted state primarily as a function of the permittivity of ice forming frost on said base material; and defined in said bedewed state primarily as a function of an ionic conduction through dew formed on said base material.
Claim 10
Dependent Claim
71 words
An apparatus in accordance with claim 4, wherein the impedance between said electrodes is: defined in said dry state primarily as a function of said resistance of said base material; defined in said frosted state primarily as a function of the permittivity of ice forming frost on said base material; and defined in said bedewed state primarily as a function of an ionic conduction through dew formed on said base material.
References Cited (Backward Citations)
US2435895A
Cited
US3226610A
Cited
US3696360A
Cited
US3757212A
Cited
US4023094A
Cited
US3873927A
Cited
US4270085A
Cited
US4272986A
Cited
US4227411A
Cited
US4281286A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-06-10 | 1988-12-10 | 1989-06-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-06-10 | 1992-12-10 | 1993-06-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-06-10 | 1996-12-10 | 1997-06-11 | $7700.00 | Window Closed / Lapsed |