Patent US1900655A successfully refreshed from Google Patents.
Patent US4176524A successfully refreshed from Google Patents.
US4176524A
Expired / Lapsed
US
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Frost detector
Assignee: Panasonic Holdings Corp
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Filing: 1977-11-02
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Granted: 1979-12-04
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Expires: 1997-11-02
Abstract
Abstract A frost detector comprises a piezoelectric element secured on a metal diaphragm and inside an air-tight space formed by the diaphragm, a base and a bellows which air-tightly and resiliently connects the diaphragm and the base, the base being secured on a fin of a heat exchanger, the piezoelectric element being connected to an oscillation circuit and an oscillation detection circuit; resonance frequency and impedance characteristic of the piezoelectric element being changed by frosting on the outside face of the diaphragm, and the frosting being detected through a change or stopping of the oscillation and resultant output signal by the oscillation detection circuit.
Inventors
- 👤 Toshibumi Kamiyama
- 👤 Kunito Miyamoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 12:08
CPC Classifications
F; F25; F25D; F25D21/00; F25D21/02; G; G01; G01B; G01B17/00; G01B17/02; G01B17/025; G01W; G01W1/00; G01W1/14
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
89 words
A frost detector comprising a piezoelectric element for connection as part of an oscillator circuit, a metal diaphragm to which said piezoelectric element is secured inside an air-tight space formed in part by the diaphragm, a base with a securing means and a resilient and heat conductive bellows connecting said diaphragm to said base and completing enclosure of the air-tight space, said diaphragm and said base being made of heat conducting material and said base including securing means for securing it in a heat-conductive manner to a cooling point.
Claim 2
Dependent Claim
89 words
A frost detector comprising a piezoelectric element for connection as part of an oscillator circuit, a metal diaphragm to which said piezoelectric element is secured inside an air-tight space formed in part by the diaphragm, a base with a securing means and a resilient and heat conductive bellows connecting said diaphragm to said base and completing enclosure of the air-tight space, said diaphragm and said base being made of heat conducting material and said base including securing means for securing it in a heat-conductive manner to a cooling point.
Claim 3
Dependent Claim
20 words
A frost detector of claim 1 wherein said base having a diaphragm drying electric heater in a recess formed therein.
Claim 4
Dependent Claim
15 words
A frost detector of claim 2 wherein said electric heater consists of positive characteristic thermister.
Claim 5
Dependent Claim
18 words
A frost detector of claim 1 wherein outer surface of said diaphragm has a coating of water-repellent film.
Claim 6
Dependent Claim
26 words
A frost detector of claim 1 wherein said securing means is a heat conductive engaging means for engaging with a defrosting heater of a heat exchanger.
Claim 7
Dependent Claim
43 words
A frost detector of claim 1 which further comprises a frost plate of heat conductive material which is heat-conductively secured to said base in a manner that said frost plate faces to said diaphragm with a gap inbetween and said gap being adjustable.
Claim 8
Dependent Claim
12 words
A frost detector of claim 6 wherein said frost plate has perforations.
Claim 9
Dependent Claim
32 words
A frost detector of claim 1 wherein said bellows is connected to said diaphragm on a node circle which is inside by a specified distance from the peripheral edge of said diaphragm.
Claim 10
Dependent Claim
23 words
A frost detector of claim 1 wherein said base has a clip for mounting the base on a fin of a heat exchanger.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-12-03 | 1983-06-04 | 1983-12-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-12-03 | 1987-06-04 | 1987-12-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-12-03 | 1991-06-04 | 1991-12-04 | $7700.00 | Window Closed / Lapsed |