Combination microwave and thermal self-cleaning oven with an automatic venting arrangement

摘要

A domestic combination microwave and electric self-cleaning oven of the type providing a plurality of operating modes including a microwave mode and a self-cleaning mode is provided with an arrangement for preventing an undesirable buildup of humid air in the cavity when operating in the microwave modes. The venting arrangement includes a restricted air inlet passageway provided to allow outside air to enter the cavity. Air is vented from the cavity through an air exhaust passageway. A catalytic oxidation unit is provided in the air exhaust passageway to decompose gases generated when the oven is operating in the self-cleaning mode. The restricted air inlet passageway is configured to limit unaugmented air flow into the cavity to a level sufficient to facilitate the proper operation of the oxidation unit during operation in the self-cleaning mode. A humidity sensor for sensing the relative humidity of the air exiting the cavity through the exhaust passageway is provided in combination with a blower operative when energized to substantially augment the flow of air into the cavity and blower control circuitry responsive to the sensor and operative to energize the blower when the sensed relative humidity level exceeds a predetermined threshold level. The control circuitry enables energization of the blower only when operating in the microwave modes so that only the unaugmented air flow occurs in other operating modes.