Heating apparatus
US5235148A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 17, 1990 |
| Grant date | Aug 10, 1993 |
| Priority date | — |
| Expiry date | Apr 17, 2010 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S99/14
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A heating apparatus such as a microwave oven in which thermal energy of high-temperature vapor generated by heating an object is detected by a pyroelectric element and a resulting detection signal is used to control (stop) a heat source such as a microwave source, etc. Among AC voltages generated by the pyroelectric element due to heat exchange of the pyroelectric element, a voltage of a polarity generated at the time of heat discharge (temperature decrease) of the pyroelectric element is selected through a circuit means. A voltage generated by heat exchange between air moving slowly in a heating chamber and the pyroelectric element caused by the rotation of a turntable or the like is eliminated by another circuit means. A control section controls the operation of the heat source by deciding an output signal of the pyroelectric element by comparing it with a detection level determined in accordance with a noise level for a predetermined length of time after the start of the heating operation. Erroneous detection is thus prevented which otherwise might be caused by a noise voltage generated in the pyroelectric element by the thermal energy of a hot air staying in the heating chamber…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.