Claims
- 1. A portable microwave oven designed to be powered from a domestic power socket having a standard maximum power rating comprising two side walls, a base, a top wall, a rear wall and a closable front door together defining an oven cavity, a magnetron for supplying microwave power to the said cavity, a blower motor for generating a flow of cooling air for said magnetron, a rotatable turntable on the base of said cavity for supporting food thereon, a port in one of said side walls of said cavity, a vent in the rear wall, a shutter movable between an open position in which air is blown through the port and into said cavity by the blower motor and a closed position in which said shutter prevents air delivered by said blower motor from reaching said cavity, a by-pass duct extending from an inlet adjacent the magnetron to an outlet at the rear of the oven, thermal heating means capable of heating the air within said oven cavity, and control means operative to supply continuous microwave power to said cavity simultaneously with the supply of thermal power to said cavity so that the microwave power heats the inside of the food while the thermal power dissipates the resulting moisture and browns the external surface of the food, said thermal heating means comprising an electrical heating element and fan means for recirculating air over said element and through said cavity, said fan means causing a forced flow of air heated by said electrical heating element to enter said cavity from one side thereof, to pass over said turntable and thereafter leave said cavity from the other side thereof, said shutter being in the closed position thereof when said electrical heating element is energized so that air blown over the magnetron by the blower motor passes along the by-pass duct to atmosphere, and said shutter being in the open position thereof to vent the cavity when said electrical heating element is de-energized so that air blown over the magnetron by the blower motor divides into two paths one of which passes through the port of the cavity and thence through the vent to atmosphere and the other of which passes along the by-pass duct to atmosphere.
- 2. A microwave oven according to claim 1, wherein said vent has vent holes leading to a vent outlet disposed adjacent the outlet of said by-pass duct so that air issuing from said by-pass duct disperses moisture or condensation in the region of said vent outlet.
- 3. A microwave oven according to claim 2, wherein said vent holes are disposed above an outlet through which said recirculating air is drawn from said cavity by said fan means.
- 4. A microwave oven according to claim 2, comprising a back panel of the oven which encloses said region into which said vent outlet and said by-pass introduce air and moisture, said panel being shaped to direct air and moisture upwardly away from said region to the atmosphere.
- 5. A microwave oven according to claim 1, comprising spring means that urge said shutter to the open position thereof, actuating means being provided to move said shutter to the closed position thereof when said electrical heating element is energized.
- 6. A microwave oven according to claim 5, wherein said actuating means comprises an electromagnetic solenoid which is energized when the electrical heating element is energized.
- 7. A microwave oven according to claim 1, wherein said blower motor is energized whenever the oven is switched on so that an idling mode, before or after cooking, air is blown by said blower motor over said microwave generator, through the open said port and into said cavity to vent the latter sufficiently to ensure that cooking commences with said cavity in a substantially cool condition.
- 8. A microwave oven according to claim 1, comprising a housing attached to said one side wall of said cavity on the external side thereof, said housing having an inlet adjacent said magnetron to receive air blown thereover by said blower motor, a first outlet which is closable by said shutter and which registers with said port and a second outlet which registers with said by-pass duct leading over the top of said top wall.
- 9. A microwave oven according to claim 8 wherein said housing is molded from a plastic material and has said shutter pivotally mounted therein.
- 10. A portable microwave oven designed to be powered from a domestic power socket having a standard maximum power rating comprising two side walls, a base, a top wall, a rear wall and a closable front door together defining an oven cavity, a magnetron for supplying microwave power to said cavity of the oven, a blower motor for generating a flow of cooling air for said magnetron, a rotatable turntable on the base of said cavity for supporting food thereon, a port in one of said side walls of said cavity, a vent in the rear wall, said vent leading to a vent outlet at the rear of the oven, a shutter mounted adjacent the port and movable between an open position in which said port is open and air is blown through said port and into said cavity by said blower motor and a closed position in which said port is closed by said shutter which prevents air delivered by said motor blower from reaching said cavity, thermal heating means capable of heating the air within said oven cavity, and control means operative to supply continuous microwave power to said cavity simultaneously with the supply of thermal power to said cavity, so that the microwave power heats the inside of the food while the thermal power dissipates resulting moisture and browns the external surface of the food, said thermal heating means comprising an electrical heating element and fan means for recirculating air over said element and through said cavity, said fan means causing a forced flow of air heated by said electrical heating element to enter said cavity from one side thereof, to pass over said turntable and therefter leave said cavity from the other side thereof, said shutter being in the closed position when said electrical heating element is energized and in the open position to vent the cavity when said electrical heating element is de-energized so long as the oven is switched on, said blower motor being energized and means being provided to direct at least some of the air delivered by said blower motor to a region adjacent said vent outlet to prevent condensation in said region.
FIELD OF INVENTION
This invention relates to microwave ovens and to methods of cooking food. The application is a continuation-in-part of U.S. Ser. No. 513,296, filed 7-13-83, now U.S. Pat. No. 4,508,947, 4/2/85.
US Referenced Citations (9)
Foreign Referenced Citations (2)
Number |
Date |
Country |
1172918 |
Dec 1969 |
GBX |
1332122 |
Oct 1973 |
GBX |
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
513296 |
Jul 1983 |
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