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3944785 Electrode boiler with automatic control  
An electrode boiler includes a plurality of veritcal electrodes arranged in a container having an open steam outlet at its top whereby the boiler operates at substantially atmospheric pressure. The...
3943331 Temperature control circuit  
A temperature control circuit is disclosed for controlling the firing angle of a thyristor such as a silicon controlled rectifier connected in series with a heater across an alternating power...
3943326 Temperature control circuit for a hand held soldering tool  
In an electrical soldering iron having a soldering tip which is heatable to a predetermined operating temperature by means of an electrical heater element and in which electrical heating and...
3942075 Semi-conductor thermal protection arrangement  
A semi-conductor thermal protection arrangement is disclosed for use with class AB, B, or C power amplifiers or in any other circuit configuration wherein a reduction in drive signal at a stage...
3937989 Temperature discrimination apparatus  
A temperature discrimination apparatus is disclosed which comprises a first switching device exhibiting regenerative switching action at a power level which is dependent on the temperature sensed...
3937921 Temperature control system  
A temperature control system comprises a heat sink heatable upon application of electric power thereto, an AC power source for heating the heat sink, temperature detector means for detecting the...
3937922 Control system  
A control system for controlling a condition, such as temperature, to maintain that condition in a generally enclosed space near a selected condition value. The system has a condition responsive...
3925139 Seal monitoring apparatus  
Seal monitoring apparatus is employed in a packaging machine as a quality control device insuring that heat seals formed in a film wrapper or casing are adequately secure. The apparatus includes a...
3924102 Apparatus for controlling temperature  
Apparatus for controlling the temperature of a heating element comprising means to monitor the instantaneous magnitude of an electrical property of the element such as the impedance thereof....
3920955 Electronic thermally sensitive switch device  
Two thermally sensitive thyristors are connected in reverse parallel between a gate electrode of a triac and the junction of two resistors serially connected across both main electrodes of the...
3911251 Heating device for molding  
The heating device is for use inside a molding channel and includes a heating coil and a probe tube isolated from the heating coil but in thermal contact with molten plastic at the gate of the mold.
3909675 Protection circuit  
The disclosure relates to a motor protection circuit utilizing PTC sensors and all solid state circuitry to provide protection to a motor circuit and the like. The protection circuit is capable of...
3903395 Temperature control system  
A temperature control system having an electric heating device selectively energizable by way of a gate controlled semiconductor switch according to indications from a temperature sensing element....
3902040 Temperature compensating vehicle window heating system  
A vehicle window heating system for eliminating moisture deposited on the surface of a vehicle window is provided with a moisture detecting circuit having a temperature sensitive element adapted to...
3896289 Aquarium water heater  
A solid-state immersion-type electric aquarium heater comprising (a) a typical electric heating element, (b) a negative temperature coefficient thermistor, (c) alternating current supply means and...
3883716 TEMPERATURE CONTROLLED SOLDERING INSTRUMENT  
A lightweight, compact soldering and desoldering instrument including a temperature sensor at the soldering tip. The sensor is of a type to provide a large change of resistance with a small change...
3881091 Control for injection molding  
A control for heating currents in multiple cavity molds in injection molding machines. The principal features include separate modular power controls each having variable resistor means with an...
3881085 Fuser control circuit for copying apparatus  
A circuit for controlling power to the fuser of an electrostatic type reproduction machine in response to voltage levels across the fuser heat source as monitored by a transformer-rectifier...
3869597 Self-regulating proportionally controlled heating apparatus and technique  
A self-regulating proportionally controlled heating apparatus and technique is provided wherein a single electrical resistance heating element having a temperature coefficient of resistance serves...
3866587 AUTOMOTIVE FUEL HEATING CONTROL SYSTEM  
To provide for predetermined heating of fuel applied to an automotive internal combustion engine, in spite of widely varying supply voltages, a heating resistance is connected, together with a...
3866019 ELECTRICAL CONTROL CIRCUIT  
An electrical load monitoring and switching system comprises total load measuring means arranged to monitor an electrical supply, switch means connectible to control the supply of electrical power...
3858027 ROAD VEHICLE REAR WINDOW HEATER CIRCUITS  
A road vehicle rear window heater circuit is operated by a manually operable switch urged to an open position. Closure of the switch charges a capacitor, which controls a bi-stable trigger circuit...
3857017 UNITARY THERMAL REFERENCE SOURCE  
A thermal reference source in which the interrelated functions of heater, radiator, and temperature sensor are provided by a unitary and integrally formed structure. The reference is formed of a...
3855452 KILN HEATING CONTROL SYSTEM  
A control system for an electrically heated ceramic kiln utilizes a plurality of heating coils and a plurality of switching elements connected to the coils so that each coil has more than one...
3854034 SYSTEMS INCORPORATING APPARATUS AND METHODS FOR SIMULATING TIMED RELATED TEMPERATURES  
The present invention relates to methods and apparatus for establishing and controlling thermal systems wherein sensing means may anticipate or log temperature conditions at other points, such as...
3845274 TEMPERATURE CONTROLLER FOR HYBRID PROCESS TANKS  
A temperature-regulating system to maintain the temperature of liquid containers in a hybrid process tank at a desired level, the vessel being constituted by an inner plastic vessel and an outer...
3842243 TEMPERATURE CONTROL SYSTEM FOR PROPORTIONAL ELECTRIC HEATING  
A temperature control system for proportional control of an electrically energized heating element. The control employs a gate-triggerable semiconductor current switching device (triac) for...
3842241 ELECTRICALLY HEATED AQUARIUM TANK  
An aquarium tank has a transparent nonmetallic wall to the exterior of which is adhesively secured in heat exchange relationship a thin plate like heater controlled by a temperature control having...
3838248 TEMPERATURE CONTROL DEVICE FOR THERMOSTATIC OVEN  
A temperature control device for a thermostatic oven or the like is provided with an input temperature-sensitive, resistive bridge network. Any imbalance voltage in the bride network is integrated...
3831003 CIRCUIT ARRANGEMENT FOR THE STEADY TEMPERATURE CONTROL  
A circuit arrangement for effecting a uniform temperature control, utilizing a resistance bridge having a temperature-dependent resistance as a temperature sensor and an operational amplifier in...
3831042 TEMPERATURE COMPENSATION CIRCUIT FOR SENSOR OF PHYSICAL VARIABLES SUCH AS TEMPERATURE AND PRESSURE  
A temperature compensating circuit for transducers, which have an overall negative temperature coefficient, employs a plurality of diodes connected in series with the transducer. The diodes are...
3826887 SIMPLIFIED PROCEDURE FOR TUNING PID CONTROLLERS  
Simplified procedures for tuning a PID controller are disclosed wherein variable circuit elements in the reset and rate networks are mechanically ganged together to permit simultaneous and...
3825725 THERMAL SYSTEMS INCORPORATING APPARATUS AND METHODS FOR SIMULATING TIME RELATED TEMPERATURES  
Methods and apparatus for establishing and controlling thermal systems wherein sensing means may anticipate or log temperature conditions at other points, such as at the work or loads and wherein...
3819905 HEATER CONTROL SYSTEM  
A heater control system for water bed heaters, in which system temperature sensing circuitry with a temperature sensing element is packaged together with the power supply circuitry for the...
3819960 CONTROLLER CIRCUIT  
An improved controller that provides features, such as signal summing after amplification of the error signal, thereby minimizing adverse noise effects utilizing full scale amplification to enable...
3818254 THERMALLY COMPENSATED CRYSTAL UNIT  
An apparatus for thermally compensating a piezoelectric crystal using electric current is disclosed and comprises a resistive heater and a resistive sensor each mounted to the surface of the...
3818247 TWO-LEAD ELECTRICAL CONTROL APPARATUS  
Two-lead electrical control apparatus including a pair of gate controlled switches that form a control switch and a triggering switch, the control switch being connected across a power source and...
3818320 HIGH GAIN PHASE CONTROL CIRCUIT  
A phase control circuit is provided which includes a zener diode across a full wave rectifier that is used to form a pulsating d.c. waveform each half cycle of an a.c. supply wave being used to...
3818183 ELECTRONIC TEMPERATURE CONTROL SYSTEM  
A Resistance Temperature Detector (RTD) having a predictable positive temperature coefficient produces a D.C. voltage corresponding to the temperature of a medium. A variable resistor that can be...
3816702 ELECTRONIC ISOTHERMAL DEVICE  
An electronic isothermal device capable of maintaining relatively even temperatures within a given container comprising an electronic circuit and a series of unique heaters in series therewith. The...
3813677 HEAT-SENSITIVE RECORD  
A heat-sensitive recorder using a thermal head, which is furnished with power in accordance with the speed of its movement relative to the recording sheet for the thermal control so as to obtain a...
3798416 TEMPERATURE CONTROL SYSTEMS  
Temperature control systems or regulating circuits for use with electrical heating elements of burners of electric ranges, hot plates or cook-tops, such circuits and elements being directly...
3794811 AUTOMATIC SAFETY SWITCH MEMBER  
An automatic safety circuit for monitoring the power switching means controlling the main current circuit to an electric power load to automatically cut off the current in the event of a...
3789190 TEMPERATURE REGULATION FOR ELECTRICAL HEATER  
A temperature control system for use in an electrical heating device wherein the heating element also functions as the temperature sensing element. The resistance of the heating element varies...
3784843 CONDITION RESPONSIVE CIRCUIT WITH CAPACITIVE DIFFERENTIAL VOLTAGE  
A condition responsive circuit, disclosed as including a temperature responsive element, is adapted to be connected to by a pair of terminals by an alternating current load and to a source of...
3780263 THERMAL CONTROL APPARATUS  
Thermal control apparatus for controlling the temperature of a photo-developing bath including electrically powered filaments disposed in the bath and energized by a control circuit responsive to...
3777187 CONTROLLER CIRCUIT  
Temperature controllers including a sensing device, such as a thermocouple which is temperature compensated by means of a negative temperature coefficient resistance, and which generates a signal...
3775591 OVEN HEATER ELEMENT CONTROL CIRCUIT  
A switching circuit for a heating element including a power triac in series with the heater element between one line of an alternating current source and neutral. The power triac is controlled from...
3766358 IMMERSION HEATER  
An immersion heater including a heating element immersible in a fluid for heating the latter, and a mixing device for agitating the fluid mounted on the heating element. The mixing device is...
3761737 THERMOSTAT WITH THERMALLY ISOLATED SWITCH MEANS  
A solid state type of thermostat that utilizes a switch means, such as a triac, for control of a remote ambient temperature altering means is disclosed in a number of possible applications. The...