The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 09, 1987
Filed:
Apr. 11, 1986
Shigeru Kusunoki, Kouriyama, JP;
Naoyoshi Maehara, Nara, JP;
Abstract
In an exhaust passage (37) of a heating apparatus, a piezoelectric device sensor (26) is provided for detecting the heating condition of a heated object (32), such as food in a microwave open heating chamber (31). A piezoelectric device of the sensor may be contained within 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 a conventional a.c. supply are amplified and then compared with a threshold to detect whether a sufficient amount of moisture of hot steam is emitted from the object in the heating chamber of the heating apparatus. The invention may be applied to prevent overheating of food in a microwave oven, temperature control of chemical processes, or the like, to control heating time.