Abstract: A system for space heating a dwelling, office and the like having a plurality of heating means and having a control mechanism for sequentially actuating said heating means to actuate only one said heating means at a time.

Abstract: A peak load control apparatus with operating mode selection for an electric heating system having a plurality of electric heating units arranged in two or more groups in different rooms is disclosed. When the current carried by the feeder line exceeds a predetermined value a peak load trigger or flip-flop which receives a signal proportional to the feeder current from a detector delivers a peak load signal to a first control circuit or monostable which cuts power to a first selected group of heating units for a predetermined period, and to a second time control circuit or monostable which cuts power to a second selected group of heating substantially at the end of the period during which power is cut off to the first group of heating units. The heating units are provided with programmable thermostats connected to operating mode selector switches which are connected to the feeder line.

Abstract: A load and the main conductions paths of first and second TRIACs are connected in series between first and second power terminals across which an alternating voltage is applied. The first TRIAC is for controlling the power dissipated in the load and the second TRIAC is for unconditionally removing power to the load a predetermined time after the first and second TRIACs are turned-on. The first and second TRIACs are interconnected so that the main terminal 1 (MT1) of one is connected to the main terminal 1 (MT1) of the other at a common point. A control circuit for turning-on and turning-off each TRIAC is connected between the gate electrode of each TRIAC and the common point.

Abstract: A temperature-adjustable electric soldering iron manipulable with a single hand to change the temperature of the iron comprises a handle, a circuit board, a Nichrome tip heating wire, a cover for the wire and a soldering tip. On the circuit board are two mercury switches, a diode, and five resistances, connected in a manner to provide four circuits connected with the Nichrome wire so that the tip can be heated to four different temperatures dependent upon which circuit is connected in series with the Nichrome wire. The circuit board is placed inside the handle and the mercury switches are arranged so that holding the handle in a completely horizontal position shuts off the electric circuit, but tilting it forward or backward, or turning it around to the left or to the right actuates the mercury switches by means of the function of the mercury drop which connects respective circuit contacts at either end of the switches to place a different one of the four circuits in series with the Nichrome wire.

Abstract: A safety circuit for deenergizing an electric blanket of the type utilizing a positive coefficient resistance material as the heating element positioned between a pair of spaced conductor wires. The circuit includes one or more gas tubes with parallel resistances connected across the conductor wires to sense voltage changes caused by open or short circuits and to conduct sufficiently high currents to blow a series connected fuse.

Abstract: An electrical resistance heater controller is provided with a plurality of circuit branches connected in parallel with each other and in series with a heating element and an external AC power source. Each circuit branch includes the series connection of a capacitor and a solid state switch. The switches are controlled by a gating device to switch during the zero crossing of the AC source voltage waveform. Power delivered to the heating element is controlled by varying the amount of series capacitance in the circuit.

Abstract: An electrical heating apparatus, and particularly a bedcover preferably in the form of a blanket, protected against an overheating condition and in which electrical current flow through a heating element is controlled by a pair of gate controlled bidirectional semiconductor switches electrically connected to one another in series and in back-to-back orientation. The gates of the semiconductor switches are connected through a temperature sensitive capacitor which triggers the semiconductor switches from a conductive to a nonconductive state in response to the sensing of an overheating condition.

Abstract: An electrical circuit electrically connects a timer motor for a timer in parallel with a thermostat means, the thermostat being electrically connected in series with a heating mechanism. With such a connection, heat may be applied to a drying apparatus while the timer is not running and when the thermostat opens to shut off the heat, the timer motor will run to operate the timer to advance the timer through the time cycle.The timing mechanism or timer for the control system includes at least one set of switching structures responsive to a cam, the switching structure including a terminal block, and first and second electrical contact blades cantilevered on opposite sides of the terminal block and cooperating electrical contacts to open and close electrical circuits.

Abstract: A control for modulating the duty cycle of diesel engine glow plugs has two heat sensitive, normally closed switches each thermally coupled to a respective positive temperature coefficient (PTC) of resistivity heater in turn thermally coupled to a common heat sink. The heat sensitive switches are serially connected to each other, to an ignition switch and to a glow plug relay. The PTC heaters are connected to a point between the heat sensitive switches and the relay and to ground. A third PTC heater is disposed on the heat sink intermediate the first and second heaters and thermally coupled to the heat sink. The third heater is connected to an alternator and serves to cut off power to the glow plugs after a selected after glow stage. The two heat sensitive switches can be selected to open at approximately the same temperature for a random operating mode or at slightly different temperatures for a sequential operating mode.

Abstract: A switching system for sequential connection of a plurality of loads to an alternating current supply comprises a computer for generating switch selection data in the form of serial bits along a single line to a distributor arrangement which decodes the selection data and provides control signals to switch devices which connect the loads to the supply. The distributor arrangement includes a circuit for inhibiting supply of the control signals to the respective switch devices unless the voltage of the supply phase connected by the device is substantially zero. Additionally the control signals are time-advanced with respect to the zero voltage conditions so that the switch devices can be placed in states in which they can connect a load before disconnection of a preceding load.

Abstract: In an engine preheating control system, in which the temperature of glow plugs mounted in a diesel engine is held in a constant high temperature range during the cranking operation after the closure of an engine key switch through the control of power supply to the glow plugs based upon the detection of changes of the resistance of the glow plugs, a main relay for controlling the power supply from a power supply source through a current detecting resistor to the glow plugs and a sub-relay for controlling power supply through a stable preheating resistor and the detecting resistor to the glow plugs are energized and de-energized in response to first to fourth control signals.

Abstract: A device for sealing plastic material bags having opposed jaw members movable between open and closed positions with one of the jaw members provided with a heat source and the opposed jaw member provided with a resilient jaw surface. One of the jaw members is stationary, the other jaw member is movable and is attached adjacent one end of a lever member pivoted intermediate its ends, the other end being associated with an electro-magnet with switch means for actuating the electro-magnet, the switch being actuated by manual movement of the movable jaw towards the stationary jaw. Activation of the switch controls electronic circuitry including timing means to actuate the electro-magnet to forcibly close the jaws and maintain them in a closed condition until interruption of power to the electro-magnet by a timing circuit. The movable jaw is normally biased away from the stationary jaw.

Abstract: A temperature controlled timer useful for controlling the application of power to apparatus such as automobile block heaters or the like. In one embodiment the time of application of power prior to a shut off time is decreased with increasing ambient temperature. In another embodiment the duty cycle of cyclically applied power is changed so that the power on period becomes shorter and the power off period becomes longer with increasing ambient temperature. Significant conservation of power results.

Abstract: A ceramic encased thermocouple placed within a kiln electrically controls an array of signal classifiers which, in turn, control the operation of the kiln heating elements. The temperature value at which the classifier array terminates the whole kiln heating operation is preselected as one of a plurality of discrete predetermined values corresponding to pyrometric cone temperature values.

Abstract: A dual temperature electric hair curling iron has a barrel rotatable relative to a rigid handle by means of a friction clutch therebetween. The barrel includes a plurality of apertures allowing steam or mist generated within the barrel to flow into contact with the hair being curled. An electric heater in the barrel is controlled by a low limit (220.degree. F.) thermostat and a high limit (270.degree. F.) thermostat located within the barrel. A normally open momentary contact switch manually operated by a ring-like arm encompassing the a front portion of the handle is arranged in circuit with the thermostats and heater in such a manner that the low limit thermostat controls the temperature of the barrel when the switch is in its normal open position. Closing of the switch by movement of the arm relative to the handle disables the low limit thermostat and allows the barrel temperature to increase to the limit set by the high limit thermostat thereby allowing tighter curls to be produced.

Abstract: A cartridge-type electric immersion heating element having an integrally contained, self-limiting thermostatic control included in its electrical circuit includes an electric resistance heating element embedded in compacted powdered insulating material partially filling a tubular metallic sheath open at one end. A preset thermostat is located within a thermostat sleeve positioned in close proximity with the sheath wall and has an end embedded in the insulating material. The thermostat is connected in series circuit with the heating element and the ends of power supply leads enter the sheath through the open end thereof. A body of potting compound, such as epoxy resin, completely fills the remainder of the sheath, seals the open end thereof and encapsulates the other end of the sleeve and the power supply lead ends whereby the sleeve and thermostat are securely held in position in the sheath.

Abstract: A control for modulating the duty cycle of diesel engine glow plugs has two heat sensitive, normally closed switches each thermally coupled to a respective positive temperature coefficient (PTC) of resistivity heater in turn thermally coupled to and mounted on a common heat sink. The heat sensitive switches are serially connected to each other, to an ignition switch and to a glow plug relay. The PTC heaters are connected to a point between the heat sensitive switches and the relay and to ground. A third PTC heater is mounted on the heat sink intermediate the first and second heaters and thermally coupled to the heat sink. The third heater is connected to an alternator and serves to cut off power to the glow plugs after a selected after glow stage. The two heat sensitive switches can be selected to open at approximately the same temperature for a random operating mode or at slightly different temperatures for a sequential operating mode.

Abstract: The control device has a power regulator for the timed power to the heating system of the electrical apparatus. The heating system is provided with a temperature sensor which, up to a given desired temperature, bridges the power regulator with the aid of a temperature switch, so that full power is supplied to the electrical apparatus heating system. On exceeding the desired temperature, power is supplied to the electrical apparatus via the power regulator.The temperature sensor is additionally heatable by an auxiliary heating system to obtain a variable changeover temperature of the temperature switch (22).The auxiliary heating system is preferably always switched on when the heating system of the power regulator is switched off.

Abstract: Control signals are transmitted through a.c. mains supply lines to control operation of electrical equipment powered from the supply lines. A near short-circuit condition is introduced across the a.c. mains supply lines, for example, by firing a thyristor connected in series with a fuse across the supply lines, for the final portion of positive half cycles of the mains supply voltage, thus holding the voltage to a near zero value for this length of time. A receiver coupled to the mains supply lines includes a zero crossing detector circuit which responds to the near zero voltage conditions across the supply lines to perform a particular control operation on an associated appliance connected to the receiver. Different control operations may be effected by defining the control signals over a group of half cycles of the a.c.

Abstract: A thermostatic control for electric cables used on overhanging eaves of pitched roofs in northern climates, and in rain gutters and downspouts, comprises a high temperature-limit switch and a low temperature-limit switch connected in series circuit for controlling energization to a narrow temperature range extending from the freezing temperature of water to several degrees colder. Above-freezing temperatures will melt ice and snow without supplemental heating, and sufficiently colder temperatures will not be raised sufficiently by heat loss through a building roof to thaw ice and snow accumulation on the roof and provide run-off water to the unheated eave, rain gutter and downspout where freezing can occur and result in the formation of an ice dam which will block drainage of further run-off water and which may grow in size to cause water to back-up and seep under roofing shingles to leak through the roof.

Abstract: An electric heating system employs a control unit including means to connect a resistance heater to a three pole power source and a switch to switch the connections between full voltage and low voltage as temperature is more than or less than several degrees colder than the set temperature. More uniform heating, greater comfort and significant energy savings results.

Abstract: Apparatus for disconnecting electrical powered devices from a source of electrical energy when the use of the devices is no longer needed. The apparatus includes an electrical switch movable in response to an actuation member. The switch is connected between a source of electrical energy and an electrical powered device so as to selectively connect/disconnect the device to the source of electrical energy depending upon the use of the actuation member. A second electrical switch, also responsive to the actuation member, is connected between the source of electrical energy and another electrical powered device, such as a heating/air conditioning unit, to connect/disconnect the heating/air conditioning unit to the source of electrical energy. One temperature responsive device is associated with the second electrical switch in order to maintain the room temperature above a predetermined minimum temperature.

Abstract: A primary thermostat is provided in a fryer of the type comprising a frypot containing cooking oil, a heater, heat control switching means for operating the heater and a thermostat including a temperature probe, the fryer thermostat being used as a backup to the primary thermostat. The primary thermostat utilizes the signal of a temperature probe associated with a cooking computer which calculates the cooking time period for food items cooked in the fryer. The primary thermostat includes comparators monitoring for open or shorted conditions of the cooking computer temperature probe, and a control transfer relay which switches thermostatic control of the fryer from the primary to the backup fryer thermostat in the event of probe failure. The primary thermostat also includes a temperature selection switch for selecting a desired temperature of the cooking oil and temperature control circuitry for operating the fryer heater to maintain the desired temperature.

Abstract: A remote control device for controlling the operation of a conventional domestic water heater (18) used singularly or in conjunction with a solar heating system. The control device comprises a remote control head (10), which has an indicator (12) for conveying the status of the water heater (18) and the temperature of the water contained therein and a multi-positional manual switch (14) for selecting the mode of operation of the water heater (18) and a remote controlled heater switch (16), electrically connected to the remote control head (10), which controls power to the water heater (18) in response to signals from the remote control head (10). Therefore, the operation of the water heater can be controlled according to the needs of the user.

Abstract: An electrical heating apparatus, and particularly a bedcover preferably in the form of a blanket, protected against an overheating condition and in which electrical current flow through a heating element is controlled by a pair of gate controlled bidirectional semiconductor switches electrically connected to one another in series and in front-to-front orientation. The gates of the semiconductor switches are connected through a temperature sensitive capacitor which triggers the semiconductor switches from a conductive to a nonconductive state in response to the sensing of an overheating condition.

Abstract: An overtemperature protector for an appliance having an electrical heating element, the overtemperature protector being formed basically of just a spring blade positionable to bring a contact on the surface of the blade into circuit-energizing engagement with a fixed contact, and an insulator-capped fusible pin retaining the blade in that position. Excessive heat in the appliance softens the pin, allowing the spring blade force on the insulator cap to shear the pin and interrupt the circuit. The overtemperature protector is preferably incorporated in a thermostatic control, the fixed contact being supported on a lateral extension projecting from one circuit element of the thermostat assembly and the spring blade being supported within the assembly with an insulating spacer separating it from the thermostat element having the lateral extension. The spring blade is preferably sickle-shaped for compactness despite having a long length for low force to minimize effects of creep of the fusible pin.

Abstract: A thermostat is disclosed which includes a bimetal element in the form of an elongated strip and a trip mechanism formed by an elongated metal strip and a member having a U-shaped portion operative as a spring and an arm portion projecting from one leg of the U-shaped portion to form a reset lever. The trip mechanism operates electrical contacts on metal strips and has an over-center operation to provide a snap action. The thermostat is connectable in series with a cooking temperature control thermostat of a popcorn cooking machine to protect against dangerously high operating temperatures.

Abstract: In an electric bedcover of a type wherein a safety thermostat having a bimetallic element is adapted to deenergize a heater when the bimetallic element is heated sufficiently, as when an overheated condition occurs, an elongated flexible sensor of a type comprising a pair of conductors spaced from each other by a layer of material having a negative temperature coefficient of resistance is adapted to influence the bimetallic element through a resistor, which is mounted for heat dissipation to the bimetallic element, and a first circuit branch comprising the resistor, the conductors, and the layer between the conductors, in series with each other, is connected so as to maintain the conductors at different potentials when the heater operates, and so as to conduct sufficient current to cause the resistor to conduct sufficient heat to cause the bimetallic element to open the contacts when some part of the layer between the conductors is heated so as to act as an electrical conductor having a low impedance rather t

Abstract: A cooking device with a microwave heater and a gas heater as well as a cooling fan for the microwave heater. A first circuit operates the microwave heater and is connected to a source of electric power through a first switching circuit. A second circuit operates the gas heater and is connected to the electric source of power through a second switching circuit, as well as a switch arranged to be operated with a gas cock. A driving circuit for the cooling fan is connected to that switch so as to be parallel with a circuit connecting in series the second circuit and the second switching circuit. The switch, furthermore, has a first contact connected to the electric source of power through the first switching circuit and has a second contact connected to the source of power without passing through the first switching circuit, while being arranged to be connected to the first contact when the gas cock is closed and to the second contact when the gas cock is opened.

Abstract: A power control system is disclosed for controlling the power output of a resistive heater element in response to operator selected power level settings by varying the rate at which a power pulse of constant duration is applied to the element. The system includes circuitry for generating a control signal representing a selected power output for the element, circuitry for identifying recurring patterns of a binary counter, the patterns recurring at different rates, and a logic arrangement for uniquely associating each of the patterns with a selected power setting. The binary counter and the power pulse control are synchronized with the power supply to trigger a power switching device at or near zero crossovers of the supply.

Abstract: A heating circuit, in particular for an electric blanket or pad, comprises an elongate heating conductor and switch connected in series between input terminals for connection to an AC supply. Switch control is operative to close the switch to cause current to flow through the heating conductor. The circuit further comprises a sensor conductor coextensive with the heating conductor, and a temperature sensitive resistance coextensive with the heating and sensor conductors and having an impedance that falls with increasing temperature. A resistor is connected in series with the sensor conductor such that a current dependent on the impedance of the temperature sensitive resistance flows through the resistor, whereby the voltage across the resistor varies with said impedance. Voltage sensing structure is responsive to the voltage across the resistor reaching a predetermined value to inhibit operation of the switch control, thereby to provide normal and/or overtemperature control.

Abstract: A temperature control circuit for a point-of-use water heater comprises a pulse charging circuit which includes a summing capacitor provided with a residual charge thereon at the beginning of each half cycle of an a.c. supply. The residual charge on the summing capacitor determines the pedestal charge on a timing capacitor and thereby the phase angle at which a ramp superposed on the pedestal fires a programmable unijunction transistor to provide a pulse for triggering switching means to supply a fraction of the a.c. supply to the heater each half cycle. The residual charge on the summing capacitor is determined each half cycle by the discharging thereof in accordance with a load current pulse feedback circuit and the output of a comparing circuit which compares the actual temperature of the water flowing past the heater with a desired set temperature.

Abstract: A heating circuit comprises input terminals for connection to an AC supply, an elongate heating conductor and a switch connected in series between the input terminals, a switch control operative to close the switch to cause AC current to flow from the supply through the heating conductor, an elongate sensor conductor spaced from the heating conductor, and a temperature sensitive element disposed between the heating and sensor conductors and responsive to over-heating at any position along the length of the heating conductor to drop substantially in impedance at that position to connect the sensor conductor to the potential of the heating conductor at that position.

Abstract: A heating device having a thermal store provided with an electrical heater has said heater controlled by a charge control circuit which includes a programme generator delivering an output signal in the form of a programme corresponding to a load balancing condition and includes a state of charge sensor which delivers a state of charge signal compared with the programme in a comparator. The heater for the store comprises a plurality of heating elements, the number of which brought into operation to charge the store is controlled by a weather signal provided by an outside temperature sensor. Preferably the comparator provides a delay from the beginning of the off-peak period before energization of the heater starts.

Abstract: A control circuit including at least one switch and a plurality of rectifiers for selectively applying a-c utility power to either or both of two remote electrically-powered apparatus at respective first and second states of rectification by means of a conventional two-wire interconnection cable. Where one of the apparatus is of a type, such as a motor, adapted to be powered by a full-wave a-c, the control circuit includes a relay and relay switch responsive to switch-selectable half-wave a-c for connecting the motor to receive full-wave power. In one disclosed embodiment, the two apparatus comprise a composite smoke detector and lamp fixture, and the control circuit provides continuous power at a first state of rectification to the smoke detector portion of the fixture and switch-selectable power at a second state of rectification to the fixture lamp.

Abstract: A water heater control system is provided to lower the temperature to which hot water is heated during periods of low use, and raise the temperature back up during periods of peak demand. The unit described herein is adapted for use on a recirculating hot water system used in apartment buildings and includes a first thermoswitch disposed on the outflow pipe from the hot water tank which feeds this recirculating system. This pipe is hotter during periods of low use because the heater is adequate to provide continuous supply of very hot water which has not been drained by tenant use. Thus this thermoswitch is directly wired to a thermostat control to reduce the heater temperature when the thermoswitch is hot.

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: Safety back-up and alarm circuit for loads such as electrical heaters and the like comprising a back-up substitute load for the primary load, e.g., an electric heater, switching circuits responsive to outputs from the primary and back-up loads, and which automatically replace the primary load with the back-up load upon failure of the primary load, said switching circuits including a circuit which reliably reads the output from the primary load and distinguishes failure of the primary load from mere non-load -- including impedance in the primary load circuit, a primary alarm element, e.g. a lamp, bell, or buzzer responsive through said switching circuits to a failure of the primary load and an energizing of the back-up load and a secondary alarm element, e.g. a bell or buzzer responsive to a failure of said back-up element.

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: Means for varying the heating rate of an immersion heater in a hot-water extraction unit comprising a solution tank in which an electrical immersion heater is mounted in order to decrease the warm-up time of the unit. In the preferred embodiment, the means comprise (a) a first heating element having a first watt rating; (b) a second heating element having a second watt rating, lower than the first watt rating; and (c) means for selectively actuating one or the other of the two heating elements.

Abstract: Apparatus for controllably heating a vehicle window having a heating grid is described including an oscillator and a signal detector, with a signal circuit coupling the oscillator and the signal detector having a DC voltage component at one or more points thereof. One or more humidity detectors are coupled to the signal circuit to control the amplitude of the oscillations supplied from the oscillator to the signal detector, advantageously by voltage divider action, and capacitor means provides DC isolation between the humidity detector(s) and any DC voltage component in the signal circuit, and also between humidity detectors when a plurality are used. Advantageously the humidity detector(s) are directly connected to the heating grid, and varying DC voltage levels at the point(s) of connection to the grid are isolated by the capacitor means. Particular arrangements of the humidity detectors on the window and connections to the heating grid are described.

Abstract: This invention is comprised of a thermostatically controlled safety circuit and device used in conventional hot air oil burning furnaces which automatically turns the oil burner off when the temperature of the room heated by the furnace becomes abnormally hot. By so doing an overheated furnace and possible fire is avoided. The invention is comprised of a line voltage or safety thermostat positioned at or near the location of the conventional furnace thermostat. The line voltage thermostat is connected between the limit switch and the control circuit of the furnace control circuit. A variation of the invention is comprised of the line voltage thermostat or safety thermostat connected or ganged with the conventional furnace thermostat so that the line voltage thermostat will be activated at a higher temperature than the conventional thermostat.