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EP0198430A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

Heating apparatus with piezoelectric device sensor

Assignee: Panasonic Holdings Corp
•
Filing: 1986-04-10
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Granted: —
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Expires: 2006-04-10
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Abstract

Abstract in an exhaust passage (37) of a heating apparatus, a piezoelectric device sensor (26) is provided for detecting heating condition of an object (32), such as food in a microwave oven heating chamber (31). A piezoelectric device of the sensor may be received in a metal casing (53) and be hermetically sealed. An output signal from the piezoelectric device sensor is processed by circuitry including an amplifier (27) having a predetermined frequency response so that only particular frequency components lower than that of commercial a.c. supply are amplified and then compared with a threshold to detect whether sufficient amount of moisture or hot steam is emitted from the object in the heating chamber of the heating apparatus. The invention may be applied to the prevention of overheating in a microwave oven, temperature control of chemical processes or the like to control heating time.

Inventors

  • 👤 Shigeru Kusunoki
  • 👤 Naoyoshi Maehara

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-11-07 08:57
CPC Classifications
H; H05; H05B; H05B6/00; H05B6/64; H05B6/66; H05B6/68; H05B6/6435; B; B01; B01J; B01J19/00; B01J19/08; B01J19/12; B01J19/122; B01J19/126; H05B6/642; H05B6/6447; H05B6/645; H05B6/6458; H05B6/666; B01J2219/00; B01J2219/08; B01J2219/12; B01J2219/1203; B01J2219/1206; B01J2219/1209; B01J2219/1212; B01J2219/1215

Claims Analysis

Total Claims: 7
Claim 1
Independent Claim 59 words
A heating apparatus comprising: (a) a heating chamber for receiving an object to be heated; (b) a heat source for heating said object; (c) an exhaust passage through which gasses in said heating chamber are exhausted; and (d) a piezoelectric device provided to said exhaust passage for producing an output signal indicative of the heating condition of said object.
Claim 2
Dependent Claim 59 words
A heating apparatus comprising: (a) a heating chamber for receiving an object to be heated; (b) a heat source for heating said object; (c) an exhaust passage through which gasses in said heating chamber are exhausted; and (d) a piezoelectric device provided to said exhaust passage for producing an output signal indicative of the heating condition of said object.
Claim 3
Dependent Claim 23 words
A heating apparatus as claimed in Claim 1, wherein said piezoelectric device is hermetically covered by a casing made of a heat-conductive material.
Claim 4
Dependent Claim 63 words
A heating apparatus as claimed in Claim 1, further comprising: (a) an amplifier responsive to an output voltage from said piezoelectric device; (b) a comparator for producing an output singal when said output voltage from said amplifier exceeds a threshold voltage; and (c) an alarming device responsive to said output signal from said comparator for indicating a predetermined heating condition of said object.
Claim 5
Dependent Claim 43 words
A heating apparatus as claimed in Claim 3, further comprising means for selecting components, whose frequency is lower than that of commercial a.c. supply, so that only such frequency components of said output signal from said piezoelectric device are amplified by said amplifier.
Claim 6
Dependent Claim 59 words
A heating apparatus as claimed in Claim l, further comprising: (a) an amplifier responsive to an output voltage from said piezoelectric device; (b) a comparator for producing an output singal when said output voltage from said amplifier exceeds a threshold voltage; and (c) a control circuit responsive to said output signal from said comparator for controlling said heat source.
Claim 7
Dependent Claim 43 words
A heating apparatus as claimed in Claim 5, further comprising means for selecting components, whose frequency is lower than that of commercial a.c. supply, so that only such frequency components of said output signal from said piezoelectric device are amplified by said amplifier.

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