Smoke and vapour detector for microwave oven

摘要

A smoke and vapour detector for microwave ovens comprises a light transmitter (12) and two light receivers (13, 14) arranged in a housing (11) through which air from the microwave chamber flows during a heating procedure. One receiver (13) is designed to receive direct light from the transmitter (12), and the other receiver (14) is designed to receive indirect or scattered light from the interior of the housing (11). The signals from the receivers are differentiated and subtracted from one another in order to generate a difference signal indicating the presence of smoke or water vapour in the chamber air.