PURPOSE: To detect a degree of removal of stain of food adhered to a wall surface of a heating chamber and keep the stain removed within a required period of time by a method wherein a humidity of a discharging passage containing oxidizing catalyst is detected by a humidity sensor.
CONSTITUTION: A heating chamber 1 is heated up to various cooking temperatures with an electrical heater 2. When a stain 6 adhered to a wall surface of the heating chamber is to be removed, it is heated up to 450W500°C. A discharging passage 3 is provided with an oxidizing catalyst 4 and a humidity sensor 5 is installed behind the oxidizing catalyst 4. When a smoke 7 passes through the oxidizing catalyst 4, a complete combustion is carried out through the oxidizing catalyst 4. At this time, a certain humidity is generated, so that atmosphere in the discharging passage 3 containing the oxidizing catalyst 4 becomes a condition in which a humidity is increased. When humidity of the atmosphere within the discharging passage 3 is detected by a humidity sensor 5, it is possible to detect easily whether or not a stain 6 of food adhered to a wall surface of the heating chamber 1 could be removed. So, it is sufficient to keep the heating chamber 1 for a period for the above-described temperature and so the stain 6 can be kept removed for a required period of time without consuming any useless energy.
FUKUDA YU
SHITAYA TAKEO
NAGAI TAKESHI
