OPTIMUM TIME RATIO CONTROL SYSTEM FOR MICROWAVE OVEN INCLUDING FOOD SURFACE BROWNING CAPABILITY

摘要

9D-RG-13054-Payne/HurkoOPTIMUM TIME RATIO CONTROL SYSTEMFOR MICROWAVE OVEN INCLUDING FOODSURFACE BROWNING CAPABILITYABSTRACT OF THE DISCLOSUREAn optimized time ratio control system for a microwave ovenincluding a food surface browning system. The system is particularlyuseful where the avialable power is insufficient to operate both thebrowning system and the microwave energy generating system at the sametime, and where the browning system has a relatively high thermal mass.A timing means is effective to establish successive time share cycles.Each time share cycle includes both a long browner ON time intervalduring which the browning system is energized at its full rated powerlevel and an alternating interval, with the time ratio therebetweenunder user control. During the alternating intervals, the browningsystem and the microwave energy generating system are alternately ener-gized, with the time ratio therebetween under the same user control. Theoverall relative apportionment to microwave cooking power is primarilydetermined during the alternating intervals with what is essentially dutycycle power level control employing power pulses of relatively shortduration. The overall relative apportionment to browner power is pri-marily determined by the time intervals between the long browner ON timeintervals, which between intervals are actually the alternating intervals.During those times during the alternating intervals when the browningsystem is energized, the browning system is at least kept warm. To com-pensate for a reduction in this "keep warm" power as the relative appor-tionment to browner power is decreased during the alternating interval,such as by user control, the long browner ON time intervals are lengthenedas the percentage of microwave power increases and the percentage ofbrowning power decreases.