Abstract: A hot plate formed by a hub from which spokes radially extend in a horizontal plane, the spokes being formed by flat strips of refractory fibrous or woven material, each positioned in a vertical plane and having upper edges in which downwardly extending notches are formed, and molybdenum disilicide wire in the form of a flat spiral having convolutions with portions inserted in the slots, the wire having terminating ends, and means for connecting the ends with electric current.

Abstract: A tankless electric water heater having instantaneous hot water output includes an open-ended folded tubular conduit having a separate metal-sheathed immersion heating element inserted in to each end of the conduit and carried by a cap member sealing the open end. Each cap member carries a thermostat having a preset temperature of about 140.degree. F. and connected in series with the heating element carried by the respective cap member. A self-regulating PTC heating cable, either disposed in or wrapped around the tubular conduit, is continuously energized independently of the metal-sheathed heating elements to maintain the water in the tubular conduit a constant temperature of about 150.degree. C. during standby periods.

Abstract: A method for making a combination heater and temperature sensor comprising the steps of forming a heater element pattern in a thin sheet of resistive material and concurrently forming a temperature sensor in a non-interfering portion of the same sheet of resistive material, the forming of the heater and sensor element patterns being carried out by a photoetching process.

Abstract: An automatic cleaning arrangement for a glass-ceramic cooking surface which is adapted to remove baked-on soils from the surface regions surrounding the individual cooking areas by the process of oxidation. Additional thin film heaters are located under the regions to be cleaned and are activated by a timer controlled power supply circuit. An interlock switch in the cook heater line disables the cook heater when the cleaning operation is in progress. The power supply circuit for the thin film heaters is arranged to disable automatically the cooking heaters when a break occurs in the glass-ceramic surface in the region of the thin film heaters.

Abstract: A time ratio control system for a microwave oven including a food surface browning system of relatively high thermal mass and operated from a limited power source. It is recognized that, since thermal (infrared) radiation is proportional to the fourth power of the absolute temperature of the radiating body, effective browning operation requires that the browning unit be allowed to reach at least a minimum temperature. Each cooking operation has a plurality of energization intervals of said microwave energy generating system and a plurality of effective browning intervals during which the browner is energized. To ensure effective browning, each effective browning interval has at least a predetermined minimum duration selected to allow the browning system time to reach at least a minimum effective temperature.

Abstract: An optimized time ratio control system for a microwave oven including a food surface browning system. The system is particularly useful where the available power is insufficient to operate both the browning system and the microwave energy generating system at the same time, 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 interval during which the browning system is energized at its full rated power level and an alternating interval, with the time ratio therebetween under user control. During the alternating intervals, the browning system and the microwave energy generating system are alternately energized, with the time ratio therebetween under the same user control.

Abstract: A flat plate surface heating unit or cooktop having a solid utensil-supporting plate that is heated by a resistive foil heating element that is bonded to a flexible, ceramic fiber paper substrate by a high temperature inorganic cement of high thermal conductivity and high electrical resistivity. The cement is formed in an electrically insulating layer that overlies the foil, and this cement hardens before the cement surface is applied against the underside of the cover plate so that the cement is not bonded to the cover plate. The soft, fibrous nature of the ceramic fiber paper substrate allows free expansion of the foil during thermal cycling. The relatively high thermal conductivity layer provides good heat transfer from the foil heating element to the utensil-supporting plate for improved efficiency.

Abstract: A flat plate surface heating unit with a utensil-supporting cover plate provided with a separate, flexible, insulation sheet supporting a resistive foil heater that is seated on a pad of dielectric material in a reinforced reflector pan. Constant upward pressure is exerted to maintain the insulation sheet with foil heater in full contact with the underside of the cover plate.

Abstract: An electric range for household cooking purposes has a cooktop with a plurality of surface heating units in the form of coils of metal-sheathed, electrical resistance heating elements. Each unit is mounted in an opening in the cooktop. A combined reflector pan and trim ring is interposed in the opening for supporting the unit, for radiating the heating energy in an upward direction and for collecting spillage. The combined pan and trim ring is manufactured of the optimum materials so it will perform its functions, and, moreover, may be cleaned in a pyrolytic self-cleaning oven without injury or discoloration.

Abstract: An electrical heating unit having a flat utensil-supporting plate of glass-ceramic or other electrical non-conductive material. On the underside of this plate are bonded multiple coil electrical resistance film heaters arranged in a generally closed loop. Each coil or loop is of substantially equal length to have about the same watts density and provide a generally uniform temperature distribution over the top surface of the heating unit.

Abstract: A flat plate surface heating unit with a glass-ceramic utensil-supporting cover plate and a metal-sheathed heating element in direct contact with the underside of the cover plate. The heating element is supported on an open framework of low thermal mass. An insulated reflector pan with a top reflective layer forms a closed housing around the heating element. The sheath is coated with a diffusion barrier of molecular film thickness, and the underside of the sheath is coated with a low emissivity coating.

Abstract: A lightweight cooking utensil with raised side walls and a high temperature flexible plastic sheet stretched across the bottom portion of the side walls and sealed thereto to form a leak-proof container. The utensil is adapted to be heated on a low energy, low temperature solid plate surface heating unit with a slight convex top surface so that the plastic sheet of the utensil will conform to the top surface and make a highly efficient thermal coupling.

Abstract: A dielectric substrate is provided with a thin narrow heater strip of multi-layer metallic films of noble metals such as platinum and gold. The film heater is bonded to the substrate and it has terminal means comprising a silver film electrode that is spaced away from the film heater. A metal oxide diffusion barrier such as a tin oxide film bridges the gap between the film heater and the silver electrode and retards the electromigration and mass flow between the film heater and the electrode.