Abstract: A sensor probe and sensor detection circuit used in an electronic temperature control circuit for preventing the control circuit from driving an external device such as a heater when the sensor probe has been disconnected from the control circuit. The sensor probe includes an NTC thermistor and a limiting resistor that are connected in parallel and potted in epoxy. The thermistor and limiting resistor of the sensor probe form part of a lower leg of a voltage divider in the control circuit. The sensor detection circuit compares the voltage signal generated by the sensor voltage divider to a predetermined threshold or ceiling voltage value. During normal operation, when the sensor probe is attached to the control circuit, the resistance of the sensor probe insures that the voltage signal from the sensor voltage divider remains within a predetermined voltage range and does not exceed the predetermined ceiling voltage value.

Abstract: An injection molding heater system for heating molding resins or plastics includes a plurality of heaters for heating resin wherein each of the heaters is positioned adjacent a nozzle or manifold. The system also includes an electrical circuit which is connected with the heaters and carries electricity from a power source to each of the heaters in order to energize the heaters. A plurality of circuit breaking devices are incorporated in the circuit for discontinuing the flow of electricity through each of the electrical circuits for preventing circuit damage in case of overcurrent, surges or the like. At least one circuit breaker is positioned in each of the electrical circuits between the power source and each of the heaters.

Abstract: A dryer control system for controlling the drying of polymer plastic pellets within a dryer hopper is provided. A series of temperature snap switches and pressure switches are strategically located within the dryer control system to cause a variety of passive fault lights to be activated to signal faults while the system continues to operate or to cause an alarm light to be activated which stops the drying cycle. The passive fault lights indicate a situation within the drying cycle which should be corrected but which is not sufficiently serious to stop the drying cycle. An alarm being activated, on the other hand, indicates a situation which requires shut-down of the drying system until the problems which caused the alarm are corrected. A programmable logic controller and a temperature controller control the operation of the system by receiving signals from the snap switches and pressure switches throughout the system.

Abstract: This Measuring Method of the electric power consumption of the Inverter Cooker enables automatic measurements of the electric power consumption for the keep-warm function, whether actual keep-warm temperature is set somewhat higher or lower, so that the productivity of the Cooker will be improved and judgement for defects of the keep-warm heaters made easier.

Abstract: Positive temperature coefficient thermistor is prepared from a sintered body of a ceramic material composition which has as a substrate BaTiO.sub.3 with metallic oxide. There is almost no difference of exothermic temperature even if different voltage is applied to the positive temperature coefficient thermistors. Thus, when the present invention is used in countries or areas in which both 110 V and 220 V of commercial voltages are used, almost certain temperature can be obtained without changing voltage by a transformer.

Abstract: An electronic thermostat for use with cooking ovens that may include oven cleaning features. An analog comparator is utilized to compare reference voltage with voltage representative temperature changes sensed within the oven, to control the oven heating element.

Abstract: An apparatus having a self contained heat source and water supply enables the wet removal of adhesively secured floor tile upon application of heat. The apparatus includes an infrared heater fed by a propane fuel tank and a water supply fed by a pressurizing water system. The method of removing floor tiles upon application of heat in a wet environment minimizes airborne asbestos dust or other contaminants. The self contained infrared heater eliminates any potential of electrical shock hazard.

Abstract: The present invention is an apparatus for controlling a water delivery system utilizing an instant flow tankless water heater. It includes a programmable microprocessor with support circuitry to achieve control of the outlet temperature of a varying flow rate and varying inlet temperature stream. The system senses a water outlet temperature and controls AC power through an on/off mechanism to regulate power to heating elements embedded in the water stream. The capabilities of the heating elements are improved through the application of using a microprocessor to perform a proportional (P), integrating (I) and derivative (D) calculation. The calculations are used to determine the operating characteristics of the heating system and to control the heating system.

Abstract: A soldering system is disclosed having a stored program microcontroller by which one or more temperatures can be selected for a soldering iron tip. The system then automatically maintains such tip temperature during the soldering operation. The programmed microcontroller is coupled through input/output and interface circuits to a heating control that in turn is connected to the iron heater element for switching AC power in units of full waveform cycles across the element while the temperature of the tip is measured by a resistor sensor and an associated bridge measurement circuit so as to produce a signal that is applied to an input of the microcontroller forming a feedback loop. This causes the resistor sensor and hence the iron tip to reach the desired temperature.

Abstract: A transition sensor is responsive to transition of a positive temperature coefficient resistive element from a nominal low resistance state to a protective high resistance state. A positive temperature coefficient (PTC) element is placed in a power distribution circuit between a power source and a load. Excessive load current in the event of a high current fault heats the PTC element to a threshold temperature at which the PTC element transitions into a protective state of high resistance, limiting current flow to the load. The LED of an optoisolator is coupled in parallel with the PTC element, preferably with a resistor in series with the LED. Under nominal current conditions the voltage across the LED is less than its forward bias voltage. During a high current fault, the LED becomes forward biased and switches on the optoisolator phototransistor to operate an alerting device such as an audible alarm and/or a light.

Abstract: A self-protecting current limiting positive temperature coefficient (PTC) resistive element arrangement protects a load circuit coupled to a power line via an actuator. Two or more PTC sections having temperature sensitive resistances are thermally coupled and electrically insulated. The PTC sections have low electrical resistance at low temperature. At least a first of the PTC sections is in series with the load and is resistively heated by excessive load current. At least one other section, thermally coupled to the first, controls the actuator by the change in its resistance induced by heat from the first section. In a three phase embodiment, five PTC sections are stacked. The first, third and fifth sections are in series with the power line phases and the load. A current fault causes excessive current flow to the load circuit, heating and increasing the resistance of the first, third and/or fifth PTC sections.

Abstract: A fast and accurate temperature controller for a device heated by current through a resistive element, such as various air data probes, wherein the resistance of the element varies with temperature. The temperature controller samples the temperature by selecting the resistance value of the resistive element. Analog calculations are performed based on the instantaneous applied voltage and current returned through the resistive element. Current through the resistive element is controlled by comparing the resistance of the element to a resistance value selected in accordance with the temperature characteristics of the element. Insensitivity to voltage and frequency variations is provided with a highly reliable and uncomplicated circuit having a small number of components.

Abstract: A heating apparatus comprising a heating member, energization element for energizing said heating member, a temperature detection member for detecting a temperature of said heating member, a first switching element for turning on/off energization by said energization means on the basis of the temperature detected by said temperature detection member, abnormal current detection element for detecting an abnormal current flowing through said heating member, a second switching element for turning off energization by said energization element, and energization stop member for operating said second switching element to turn off energization.

Abstract: A continuous flow water heater assembly requiring no storage tank and including an entrance chamber having a flow control switch mounted therein adapted to be activated upon a positive flow of water through the system wherein the water flows from the entrance chamber to a plurality of heating elements each of which are at least partially segregated by virtue of their being removably mounted within separate heating chambers. The heating chambers are attached in fluid communication to one another by a plurality, at least two, ports which are of proportionately different sizes such that water will be passed between the first and second heating chambers in proportionately different amounts through the different sized ports. Water is thereby effectively distributed between the heating elements so as to prevent exposure of the heating elements when activated and thereby eliminating either of the heating elements from being exposed to air and thereby subject to burnout.

Abstract: A thermostat for cyclically regulating actual ambient temperature, Ta, to either of two values, T1 and T2, for selectable durations. A switch allows T1 to be selected and deselected and a sensor detects Ta, while a controller is connected to the switch and the sensor. The controller is capable of defining T1 and T2 values. The controller further has a memory to store a cycle period duration, a detector to detect when the switch selects or deselects T1, and a timer which establishes T1 duration based on the time between T1 selection and deselection, and establishes T2 duration as at least a portion of the remainder of the cycle period. The controller automatically cyclically repeats the established T1 and T2 durations during each cycle period until T1 is again selected by the switch. A signal generator in the controller generates a control signal corresponding to the difference between Ta and T1 or T2 during their respective durations.

Abstract: An electrical appliance, such as a pressing iron (10), includes a user proximity sensor for removing electrical power from the appliance after a period of non-use. When a user's hand is in close proximity to, or is in a grasping relationship with, a handle (28) of the pressing iron, an antenna (44) that is disposed within the handle is capacitively coupled to the user through a dielectric material that forms the handle wall. When so coupled to the user, a displacement current having a frequency equal to the AC line electrical power frequency signal (50 Hz or 60 Hz) is capacitively coupled between the user's body and the antenna. The displacement current is detected and amplified by circuitry (60) that is connected to the antenna by a conductor (46). This circuitry outputs a signal that indicates the proximity of the user to the handle of the pressing iron. The output signal is in turn employed to disable the operation of a time-out circuit (70).

Abstract: A circuit for controlling the temperature of a system by sensing a temperature is disclosed.

Abstract: A self-regulating heater including a resistance element for converting electrical power to thermal energy and a power supply includes circuitry for controlling its output during heat up along a path bounded by two preferred paths:1) a path defined by constant voltage with a cross-over to constant current for a NTCR heater element when the power output reaches a maximum or a path defined by constant current with a cross-over to constant voltage for a PTCR heater element when the power output reaches a maximum; and2) a path defined by constant power with a cross-over to maximum current for a NTCR heater element or to constant voltage for a PTCR heater element when the power supply reaches maximum current or maximum voltage output respectively. When the heater element reaches the set control temperature, the power supply then maintains power equilibrium with the thermal load through controlling its output according to resistance control, i.e.

Abstract: In an apparatus for detecting turn-on state of plural heaters including an electric power source for supplying electric power to the plural heaters, a controller controls the electric power source to be turned on and off so that each of the plural heaters is turned on and off in a predetermined manner, and a current sensor measures the total current supplied from the electric power source to the plural heaters. Then, a comparator compares the total current measured by the current sensor with plural reference values different from each other and outputting signals for representing comparison results thereof, and a judging circuit judges turn-on or off state of each of the plural heaters based on the signals outputted from the comparators.

Abstract: A first control device controls a temperature of an object so as to make it near a first predetermined temperature. A second control device stops heating the object if a temperature thereof reaches a second predetermined temperature as a result of a temperature thereof increasing because the first control device is substantially disabled. The second predetermined temperature is higher than the first predetermined temperature.

Abstract: A method and apparatus provide input protection in a system having a controller which monitors a controller terminal for at least one monitor period. The controller terminal is coupled for bi-directional operation. The controller terminal is set to an output configuration for at least a portion of the time that the controller terminal is not being monitored by the controller.

Abstract: A control for a resistive heating element embedded within a motor vehicle seat is disclosed. In one embodiment, a transistor is biased into conduction to energize the heating element when the temperature of the element is below a threshold that is adjusted by the vehicle operator. A fault sensing system monitors operation of the control unit and de-energizes the heating element if a fault is sensed. Sensed faults include both short circuits and undesirable open circuits. Power application to the resistive heating unit can be either pulsed or continuous. In one embodiment, once a fault is detected, the heating system cannot be re-energized until the vehicle ignition switch is turned off and then returned to its on position.

Abstract: The present invention concerns improvements in electric defrost heaters used in frozen carbonated beverage machines. The frozen carbonated beverage machine includes freeze cylinders used to produce the frozen beverage. One or more tubes are secured in heat exchange relationship along the exterior of the freeze cylinder. Cartridge type heating elements are releasably insertable into the tubes to provide for defrosting of the beverage in the freeze cylinder.

Abstract: A safety mechanism for disabling a portable room heater. A lever which extends from the heating face of the heater is coupled with a shut-off switch. Movement of the lever resulting from draping of an object over the heater opens the switch and shuts off the heater. A buzzer may be wired in parallel with the switch to provide an audible alarm when the switch opens.

Abstract: In a heat roller fixing device in a printing apparatus, a pressure roller and a heat roller are arranged in opposition to each other, and a medium is passed between the rollers to fix an image formed thereon.The device comprises a heat roller unit in which the heat roller is supported by a fixing frame, and a main frame having guide rails for the heat roller unit, and the heat roller unit can be inserted in and withdrawn from the main frame along the guide rails.

Abstract: An infra-red heater (1) for a glass ceramic top cooker includes a dish containing a base layer of thermal insulating material. A peripheral wall of thermal insulating material extends around the periphery of the base layer and at least one infra-red lamp (3) extends across the base layer. A ballast device (5) is electrically connected in series with the infra-red lamp, for example in the form of a coil of bare resistance wire, and serves to reduce inrush current to the lamp. A thermal cut-out device (7) cuts off the supply of power to the infra-red lamp and to the ballast device (5) if the temperature of the glass ceramic cooking surface becomes excessive. The coil of bare resistance wire preferably has an electrical resistance which is approximately half the electrical resistance of the infra-red lamp at its operating temperature. The use of a ballast device (5) enables the infra-red lamp (3) to be used in conjunction with a cyclic energy regulator (9).

Abstract: An improved system for and method of precisely controlling the temperature at a predetermined location at a preselected temperature selected from a range of temperatures is described. The preferred system for carrying out the preferred method includes a mixing valve for separating a fluid stream into first and second component streams and adjustable in response to a first contol signal so as to control the amount of separation of first and second component streams. The preferred system also includes a heater for heating the first compponent stream in response to a second control signal, a first evaporator for cooling the second component stream and a conduit for combining the heated and cooled component streams so as to provide a mixed stream to the predetermined location. The first and second control signals are provided as a function of the preselected temperature, the temperature of the heated first component stream, the temperature of the mixed stream and the temperature at said predetermined location.

Abstract: An electric radiation heater assembly for a glass ceramic top cooker includes at least one heating element having a substantial positive temperature coefficient of resistance, such as an infra-red lamp. A resistive assembly is electrically connected in series with the at least one heating element for suppressing surges of electric current due to the low initial resistance of the heating element. Switch means is operable a time interval of at least thirty milliseconds and preferably about 1/2 second after a supply of electric power to the heater is energized so as to reduce the combined electrical resistance of the heating element and the resistive assembly.

Abstract: The present invention is directed to a device for detecting faults in an electrically-conductive heating element and more specifically concerns a digital monitor which compares internal electrical noise produced by the electrically-conductive heating element with external electrical noise produced by the heating element power source in order to determine whether faults exist in the heating element.

Abstract: A warmer for heating wet dressings and other articles disposed in a combined heating and storage compartment in stacked relation insures that a bottommost article about to be dispensed is at a proper temperature so as to avoid burning the patient to whom the article is applied. The articles in stacked relation rest on a thin aluminum plate to which an electrical heater is connected for supplying thermal energy thereto, the plate having a center aperture forming a thermal island in which a first thermal sensor is disposed which projects into the compartment in contact with the bottommost one of the articles therein. A circuit board has control circuitry for the heater thereon and is disposed beneath the plate so as to simultaneously function as a stiffener for the plate. The control circuitry is connected to the first sensor as well as to a second thermal sensor which is directly responsive to the temperature of the heater.

Abstract: A method of tire repair in which flexible heating pads are applied to both the inside and outside of a patch area of a tire casing, and held in place under equalized pressure against the patch area by inflatable means. An inner tube is the inflatable means to hold a first flexible heating pad against the inner wall of the casing and patch area, and an inflatable air bag is the inflatable means to hold a second flexible heating pad against the outer wall of the casing and patch area. A belt or girdle of flexible sheet material surrounds the inflatable air bag and casing to force the air bag against the second flexible heating pad when it is inflated. The flexible heating pad for use on the inside of the casing includes a structure which enables the heating pad to conform to the interior surface of the casing and patch area and maintain contact therewith throughout the heating surface area of the heating pad when the inner tube is inflated.

Abstract: A hazard prevention control circuit is provided for an electric heater having heating coils enclosed in a quartz tube immersed in a tank of solution. A circuit breaker is connected in series with a contactor coil controlling a set of contacts connecting the main lines of a power supply to the heating coils of the heater. Upon sensing a hazard condition, the control circuit causes excess current to flow through the circuit breaker to open the circuit and deenergize the contactor coil so as to open the contacts connecting the power to the heating coils. Transformers are provided for coupling power supplied by the main lines to the control circuit and the contactor coil and for coupling the pulse output of the control circuit to trigger a triac which conducts the excess current through the circuit breaker.

Abstract: A flexible, rope-type heat sensor interfaces in a overlapping array with exposed outer portions of U-shaped heating elements of an immersion-type heater. The sensor is connected to a controller which opens and closes circuitry connecting the heater with a power source upon selectively sensing a temperature condition of the heater elements. With such a heater installed in a liquid-containing receptacle, the temperature of the liquid can be controlled and the heater protected from inadvertent overheating. The device is also applicable to control liquid level in a receptacle.

Abstract: A constant temperature heater includes a thermistor having a positive temperature coefficient and a varistor stacked upon one another in an electrically insulating casing in such a manner that the thermistor and varistor are electrically connected in series with each other and the thermistor is in heat exchange relationship with a radiator plate on the casing. A spring in the casing presses the varistor and thermistor into firm engagement with each other and biases the thermistor into good heat conductive relation with the radiator plate. The varistor serves to reduce the transient currents in the thermistor and reduces the heat dissipation power of the thermistor, thereby providing a longer service life.

Abstract: A heating assembly having a protector for its sheet-type heating element, which is made from a sheet containing certain electroconductive fibrous or particulate materials such as carbon fibers. A detector element is formed on an intermediate resin layer having a negative temperature coefficient of resistivity, and two electrode layers are adhered to the opposite surfaces of the intermediate layer. The detector element is combined with or adhered to the sheet-type heating element, so that the whole surface of the heating element is completely covered thereby. A controlling circuit is connected between the detector element and the sheet type heating element.