Abstract: A hair waving appliance of the type having a hood assembly includes a plurality of independently controllable heating means such as infrared heaters or lamps valves each disposed to heat a different hairline area of the head of a patron. A temperature control and a timer are provided for individual ones of the heating elements for controlling a temperature and a period of heating independently of one another. In addition, an ultrasonic atomizer is provided within the head supporting assembly to generate moisture-laden air mist, imparting longer-lasting curl retention. A heating temperature or a period of heating can be determined under the control of at least either the temperature control or the timer depending upon the hair nature of the hairline areas and personal taste of the patron.

Abstract: An apparatus for storing electrically generated heat includes a sealed container holding a bed of fusible heat storage medium, such as an alkali metal hydroxide composition, and having an expansion space above the bed of material to accommodate the medium in its liquid phase. A generally horizontal main electric heating unit is located in the bottom portion of the container for heating the fusible medium above its melting point. A first vertical electric heater is provided in the bed of material in thermal contact with the main heating unit and has its active heating portion extends upwardly from the main heating unit only to the height of the heat storage medium in solid phase. A second vertical electric heater is located in the container in thermal contact with the first vertical heater with the active heating portion of the second heater extending only from the height of the fusible medium in solid phase to the height of the medium in the expanded liquid phase.

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: Regulation of the temperature of a pyrolitically cleaned cooking oven during cleaning to avoid local overheating of the oven base plate enamel. A heating-up power level is used until near the pyrolitic temperature, and then a lower power level is used for maintaining the oven at about the pyrolitic cleaning temperature. The change over takes place preferably at about 470.degree. C.

Abstract: Temperature responsive power supply apparatus for electrical resistance heating, e.g. for weld stress relief, has a power supply transformer comprising first and second secondary windings in series with one another and first, second and third conductors for connecting the secondary windings to heating elements. A pair of temperature sensors provide temperature signals corresponding to the temperatures of heated zones heated by the apparatus, and a pair of control units responsive to the temperature signals control the current flow through the conductors. A switch enables one or both control units to regulate saturable reactors or the like in series with the conductors, whereby the control unit can regulate two respective heating circuits each including one of the secondary windings or one of the control units can regulate a heating circuit including one or both of the secondary windings. The apparatus provided improved versatility for heating one or more large or small pipe welds.

Abstract: A power control method and system for a cooking appliance using a high inrush current element in which the instantaneous glow from the heater element is utilized to inform the operator of appliance turn-on. The power control includes a logic arrangement for detecting the transition of the appliance from an OFF condition to a selected one of a plurality of power level settings. Prior to energizing the heating element at the selected power level, the control energizes the element for a preselected transient time at a level to produce a visible glow.

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: Two different types of circuits, the first a coil operation circuit and the second an operating circuit can be effectively used together in connection with an assembly such as a desoldering tool having a remotely located, associated structure for use in regulating when a vacuum is available at the tool in response to manipulation of the tool. The operating circuit employed utilizes a current control circuit capable of being actuated through the use of a switch on the tool to pass a full or a half wave AC current and a load such as a heating element located on the tool. The operating circuit also includes a detection circuit for determining whether a full or half wave current is being utilized to supply power to the load which is positioned within the associated structure. The coil operation circuit is located within this associated structure and includes a bidirectional solid state switch is series with a coil, another solid state switch in parallel with the coil, and the first noted switch.

Abstract: A control circuit uses an adjustable resistance to generate a first control signal whose amplitude varies with the setting of the resistance and a second, step-like control signal whose level changes from a first to a second level at a predetermined setting of the resistance. The variable resistance is coupled to the collector of one of a pair of transistors whose emitters are commonly connected to a reference potential. The adjustable resistance's tap, which provides the first control signal, is connected to the base of the one transistor. A collector impedance and the variable resistance are coupled between the collector circuit of the one transistor and a voltage source. An output of the impedance is connected to the base of the other transistor, whose collector provides the second control signal.

Abstract: An electric time switch mechanism is provided comprising a plurality of units each having an operating thermal expansion member, for example, a bimetallic member. Electrical heating means are provided for the thermal expansion member and a switch is activated by the thermal expansion member. The units are connected in series in such a way that the activation of a switch turns off the heating means of the associated thermal expansion member and turns on that of the following units. The switches remain in the activated state after activation and are resettable by external activation.

Abstract: A cooking oven having both microwave and electrical resistance heating means and which fully utilize the capabilities of a limited-capability power source to achieve the shortest possible cooking time. The oven has a microwave energy generating system which requires less than all of the available current when operated at its full rated power level, and an electrical resistance heating element which requires substantially all of the available current when operated at its full rated power level. The oven also has a means for at least successively energizing the microwave energy generating system and the electrical resistance heating element at their respective full rated power levels. Additionally, there is a means for energizing the electrical resistance heating element from the power source at a reduced power level when the microwave energy generating system is energized at its full rated power level.

Abstract: In a cooking oven supplied from a power source of limited capability, a time ratio control system alternately energizes a microwave energy generating system and an electrical resistance heating element a plurality of times during each cooking operation to, in effect, time share the available power. The resultant concurrent microwave and electrical resistance provides improved cooking results when the power source capability is limited.

Abstract: A system having two heaters, such as a photographic processor with a solution heater and a dryer heater, has proportional controllers for each of the heaters. A priority control co-ordinates operation of the two controllers to give full priority to one of the two heaters during warm up, and a reduced percentage for running conditions. The other heater is allowed to share the remaining available input power.

Abstract: A controllable electric heating device uses a PTC resistance body having first areal electrode on one surface and two spaced apart areal electrodes of different areal size on the opposite surface in overlapping relation with a part of the first electrode to provide at least two current paths through the resistance body between the opposite surfaces. The first electrode is connected to one terminal of a voltage source. A switching device selectively connects one or more of the two spaced apart electrodes to the other terminal of the voltage source so that the effective electrode areas are altered thereby adjusting the current flow in the PTC body to produce different temperature levels of the heating device.

Abstract: A supplementary heat control for a heat pump system includes thermostatic sensors on the downstream side of the heat pump heating coil. The sensors upon sensing temperature differentials in the heated air stream which indicate the need for supplemental heat operate relays. The relays, in turn, activate power input to supplementary heating coils downstream from the thermostatic sensors. A plurality of sensors are disclosed for sensing differential temperature differentials and thus permitting staging of supplementary heat.

Abstract: A portable electric space heater has a case that surrounds separate electric heating elements, and the case has separated upper and lower airflow openings. A control switch allows manual selection of two different operating cycles, respectively suited for heater use in a large room requiring heater outputs approximately 65 to 100% of maximum to maintain a comfort level, and in a small room requiring heater outputs of only 20 to 100% of maximum. Thermostatic controls respond to the sensed ambient air temperatures to shift the heater operation automatically, in either operating cycle, for maximum heat output, for a lower modulated heat output, and for no heat output. Simultaneously with this modulated heat output, air moving means located in the case is operated at different speeds, at maximum speeds for the high heat outputs and lesser speeds or is even stopped for the lower or no heat outputs.

Abstract: An energy demand controller adaptable for a house or building having a plurality of heating zones and appliances. The energy demand controller includes a temperature sensor for each zone, a central controller receptive of all the temperatures from each zone for comparing the sensed temperature to a predetermined value, and a switch panel having solid state switches responsive to commands from the central controller for selectively delivering power from a power source to the heaters and appliances. When the zones require heating because of a first predetermined temperature difference between the sensed temperature and the desired temperature, then the heaters for the various zones are sequentially activated for a short predetermined time interval. When a greater temperature difference exists between the desired level and the sensed level in a particular zone, the heaters for that zone are activated full time.

Abstract: An electrical furnace has a plurality of electrical heaters and a control unit carried by a frame. A rigid lead unit is carried by the frame and has rigid lead means directly and electrically interconnected to terminals of the heaters and terminals of the control unit, the rigid lead unit itself having terminals for electrically interconnecting the rigid lead means to power source leads whereby the power source leads are directly and electrically interconnected to the terminals of the heater and the control unit by the rigid lead means without the need for auxiliary wiring. The control unit includes an electrical sequencing switch construction having a plurality of electrical switches for sequentially operating the heaters, the switch construction having a temperature sensing unit operatively interconnected to the switches for moving and holding the same in open conditions thereof when the temperature sensing unit senses a high temperature condition of the heaters.

Abstract: A proportional temperature control system using a linear time delay circuit provides an output voltage that is similar to the output voltage of a thermostat but delayed in time. The delay circuit is a linear rate time delay system that compares a called for voltage shift at its input to the output voltage of an integrator circuit to provide a substantially linear rate of time delay. The comparator circuit and the integrator circuit are separated by a limiter so that regardless of the amount of the initial offset in voltage at the comparator, the rate of integration is always maintained the same.

Abstract: The disclosed invention describes an apparatus and method for bringing a system having high interactive portions to a predetermined temperature distribution. The invention includes a difference controller which provides, through two separate drivers, a fixed total amount of energy to the system being controlled. If the system being controlled also has a long cycle time, second and third temperature controllers may be used to bring the system to the equilibrium temperature with a minimum amount of overshoot. The invention is particularly advantageous when used in connection with a high pressure, high temperature vessel useful in growing quartz crystals.

Abstract: A fluid tank, with an inlet and an outlet, is provided with first heating means for heating the fluid in the tank to a first temperature and a second heating means for heating the fluid to a second temperature which is lower than the first temperature. A thermostatic switch is disposed to be responsive to the temperature of the fluid in the tank outlet to enable the first heating means only when the temperature in the outlet is above a predetermined level. The fluid in the tank is maintained at a low temperature during periods of non-use, and at an increased temperature only during periods of use, thus economizing on heating energy.

Abstract: An electrical circuit for a heating system has a plurality of electrical resistance heating elements and a blower all controlled by a plurality of electro-thermally actuated relays. The circuit is arranged so that the heating elements are sequentially energized and de-energized and so that the blower is maintained in operation at all times that any one of the heating elements is energized. A thermostat controls the operation of the relays, the second and the last of which each having switches connected in series circuits with the actuator of the first relay and in parallel with the thermostat so as to maintain blower operation, which is controlled by the first relay, when the thermostat opens.

Abstract: In a multizone electrical furnace the phase shift effect of the thyristor devices used to control the power supplied to each thermal zone is reduced by providing two or more heater circuits, each including a thyristor device and a heating element, for each thermal zone. The thyristor devices are controlled so that only one thyristor device associated with each thermal zone is operating to produce a substantial phase shift at any time. Over-powering the heating elements at higher furnace temperatures may also be prevented by connected two or more heating elements associated with a thermal zone to one of the thyristor devices associated with that zone above a predetermined threshold temperature.

Abstract: An electrically heated window system having at least two independently heatable zones wherein each zone includes its own independent resistance heating element which provides a path for the flow of electric current. A selected region in one of the zones includes a secondary heating component which produces a relatively high temperature in this region of the zone which controls a thermostat in thermal contact therewith. The thermostat initially connects an electrical potential to the one zone and then automatically cycles the electrical potential between the two zones in accordance with the rise and fall of the temperature in said selected region.

Abstract: A programmable electronic control system for an array of electrical stations exemplified by food tray stations each of which is adapted to receive a food tray having two or more electrical heaters embedded in the tray. Each tray is detachable from its station. A separate power circuit is associated with each heater element at each tray station for supplying separately controllable power to each individual heater. A manually controlled programming channel is connected to each power circuit and includes means for generating control signals to enable or disable each separate power circuit to permit the programming of the entire array of tray stations. A manually controlled station reset device is connected to the programming channels for each tray station to remove any enabling control signals generated by the respective programming channels for that station to permit the re-programming of individual tray stations.

Abstract: Control apparatus for automatically enabling and disabling the thermostatic control of a plurality of building temperature control units. A programmable timer is provided for adapting the control apparatus to a desired building use schedule. A manually operable override switch is also provided to allow for temperature control during unscheduled building occupancies and additional circuitry automatically disables the override switch to prevent the control apparatus from remaining overridden for an extended period of time in the event the override switch is not reset. A temperature limit switch is further provided to return the temperature control units to thermostatic control if the building temperature drifts outside a predetermined range during periods of disablement.

Abstract: A miniature electric fluid immersion heater adapted for instantaneously heating relatively small bodies or flow increments of fluid to a predetermined temperature. The heater is particularly adaptable to be mounted immediately in advance of a hot water faucet in a home or building so as to provide a continuous flow of instantaneously heated water and thereby eliminate the standard hot water heater and the entire hot water piping system in the building. The heater comprises a small, cylindrical, thermally insulated pressure vessel having a fluid inlet and outlet as opposite ends. A series of individually actuated electrical heating elements are positioned within the vessel so as to be in intimate physical contact with the flowing fluid. The heating elements are constructed of a heavy gauge resistance element which is thinly coated with a glass or ceramic frit fused into an impervious, chemically resistant, electrically non-conductive coating having negligible thermal insulation and heat storage capabilities.

Abstract: An electric heater control circuit is shown which utilizes a 10-step controller for obtaining eighteen steps of heating control. Electrical and magnetic control circuitry operates this 10-step controller effectively through two cycles, one at a low level power output mode and a second at a high level power output mode, to thereby substantially increase the effective number of steps of heat control. In addition, means are provided for instantaneously energizing or de-energizing a plurality of small electric heaters upon shifting modes to compensate for the de-energization or energization respectively of a large heater to thereby avoid momentary periods of excess heat or cold while the controller is shifting modes.