Abstract: A microwave intensification system includes a base frame having a plurality of support members, a microwave transparent, central vessel, and at least one dielectric unit positioned within the central vessel. A cooking surface is formed by covering the dielectric unit with a protective covering. In operation, a food item is placed within a processing container and positioned on the cooking surface over the dielectric unit. The processing container is sized such that an overlap exists between the container and the dielectric unit in order to balance the exposure of the food item to a microwave energy field. With this arrangement, the food item can rapidly undergo a cooking process in a manner wherein central and edge portions of the food item are exposed to a uniform cooking process thereby increasing the quality of the final product.

Abstract: A microwave oven includes an oven cavity arranged within a housing. The oven includes a door and a motorized conveyor belt for transporting food items through the oven cavity. A microwave energy intensification system is provided below the conveyor belt to concentrate and intensify a microwave energy field directed into the oven cavity in order to minimize temperature deviations within the food item.

Abstract: A conveyorized microwave oven incorporates a shielding system mounted within an oven cavity of the microwave oven. The shielding system is provided to prevent select portions of a food item traveling through the microwave oven from overheating relative to the remainder of the food item. The present invention is particularly adapted for use in connection with the tempering, cooking or thawing of parallelepiped or rectangular-shaped food items and includes a frame structure fixedly mounted within and traversing substantially the entire length of the oven cavity, with the frame structure having a generally rectangular cross-section defined by both microwave impermeable portions and microwave transmissive portions on each side.

Abstract: A conveyorized microwave oven incorporates a shielding system mounted within an oven cavity of the microwave oven. The shielding system is provided to prevent select portions of a food item traveling through the microwave oven from overheating relative to the remainder of the food item. The present invention is particularly adapted for use in connection with the tempering, cooking or thawing of parallelepiped or rectangular-shaped food items and includes a frame structure fixedly mounted within and traversing substantially the entire length of the oven cavity, with the frame structure having a generally rectangular cross-section defined by both microwave impermeable portions and microwave transmissive portions on each side.

Abstract: A microwave apparatus includes a coaxial feed connected to a microwave waveguide and extended into a rotating antenna applicator in a microwave cavity, wherein a gap between the ceiling of the microwave cavity and the top of the rotating antenna applicator as well as between the coaxial feed and the rotating antenna applicator is present to facilitate the rotation of the antenna applicator. The presence of these gaps permit radial leakage, uncontrolled excitation of modes and occasional arcing. An annular knob is provided proximate the coaxial feed and attached to the top of the rotating antenna applicator to suppress radial leakage, uncontrolled excitations and arcing in the microwave cavity.

Abstract: A microwave oven comprises a cabinet and a door attached to the cabinet to form a food processing chamber. The door has a screen, an absorbing film, and a frame. The screen reflects microwave energy away from the absorbing film, the screen has a plurality of screen lines and a plurality of screen openings defined by the plurality of screen lines, and the screen has a screen period. The absorbing film absorbs microwave energy passing through the screen. The frame supports the screen and the absorbing film in order to form a window through the door and to maintain leakage of microwave energy through the door from the food processing chamber below a predetermined level. The frame supports the screen and the absorbing film so that the screen and the absorbing film are separated by a distance which is as least as great as the screen period, and the screen and the absorbing film are electrically attached to the frame.

Abstract: An electrical appliance includes an appliance base, a cover, power lines carrying electrical power to the appliance base, an interlock switch, and a fastener. The interlock switch has a switch case and a switch within the switch case. The switch case is affixed to the appliance base, the switch is in one of the power lines, and the switch has an open position and a closed position. The fastener is arranged to fasten the cover to the appliance base so that the fastener holds the switch in its closed position when the cover is fastened by the fastener to the appliance base and allows the switch to move to its open position when the cover is not fastened by the fastener to the appliance base.

Abstract: A commercial microwave oven having a plurality of operator actuable switches each of which is dedicated to activating the microwave oven for a corresponding programmed time period. These operator actuable switches are located on a switchboard, and a front faceplate has graphic keypads indicating where to push to activate the respective switches. Also located on the switchboard are operator actuable switches used to reprogram the time periods, but these reprogramming switches are hidden because they do not have corresponding keypads on the faceplate. Accordingly, access to the reprogramming feature is limited to those who have been appropriately instructed.

Abstract: Apparatus and method for altering computational constants stored in an EAROM of a microwave oven microcomputer. In the normal or operational mode, the microwave oven control panel is used by the operator to enter control data for the microwave oven. After a mode determining signal is applied to the microcomputer by grounding one of its specified ports, new computational constants can be entered through the control panel and stored in the EAROM so as to alter the operating characteristics of the oven.

Abstract: Control system for a microwave oven or a combination microwave and convection oven where the on time of a microwave generating system is decreased while convection heater on time may optionally be increased as a food product cooks to a predetermined, desired temperature. A temperature probe inserted in the product senses temperature and connects to a wheatstone bridge. A differential amplifier connects to the wheatstone bridge, an up/down integrator circuit connects to the differential amplifier, and a comparator connects to the integrator and which includes a latch to generate a signal to control a triac for controlling the microwave generating system and to provide a closed loop feedback signal to the temperature probe. The control system starts the oven cooking with substantially one-hundred percent power and, as the desired predetermined temperature is reached, the microwave power level is decreased through the control system.

Abstract: A digitally programmed microwave oven having a microwave generator energized by a high voltage power supply connected to an alternating current source through mechanically actuated oven door interlock switches, with the power supply regulating the current supplied to the microwave generator to compensate for peak voltage variations in the alternating current source by resonating the output of the power supply in the region of the frequency of the alternating current source in which the power supply is initially energized by a semiconductor switch actuated by a computer to accurately control the time of initial supply of power to said power supply at a point which minimizes the input current surge to said resonant circuit by actuating said semiconductor switch at a time substantially .pi./2 radians of said frequency after the zero voltage point of said alternating current source.

Abstract: A microwave oven control system in which the average microwave power may be selected by selecting different duty cycles of a cyclically closing semiconductor switch controlling the AC power supplied to a microwave magnetron anode power supply which has a saturable high voltage transformer with input current surges to said power supply being minimized by turning on said switch in the region a voltage peak of said AC power and with the cycle time of said switch being greater than the AC power cycle time but being substantially less than the thermal response time of a food body being cooked by microwave energy so that changing the duty cycle can change the power applied to the food body rapidly in the event that undesired results such as boiling over or burning of the food body are observed.

Abstract: A safety interlock system is disclosed for microwave ovens or other high voltage electrical apparatus incorporating sensor means for detecting any malfunction. Means are provided for interrupting line input power or actuating a failure indicating device or a combination of both. Thermally actuated means, such as bimetallic or meltable elements, as well as circuit breakers, relays and fuses are described. The sensor means are associated with each of the interlocks and do not carry regular equipment-load current until such time as a malfunction of the companion interlock occurs. Replacement of the faulty equipment by authorized personnel and manual resetting of the interrupt or indicating means before the oven is energized again reduce the risk of accidental radiation, electrical shock or damage to the apparatus.

Abstract: A safety interlock system is disclosed for microwave ovens or other high voltage electrical apparatus incorporating sensor means for detecting any malfunction. Means are provided for interrupting line input power or actuating a failure indicating device or a combination of both. Thermally actuated means, such as bimetallic or meltable elements, as well as circuit breakers, relays and fuses are described. The sensor means are associated with each of the interlocks and do not carry regular equipment load current until such time as a malfunction of the companion interlock occurs. Replacement of the faulty equipment by authorized personnel and manual resetting of the interrupt or indicating means before the oven is energized again reduce the risk of accidental radiation, electrical shock or damage to the apparatus. .Iadd.