Abstract: A liquid temperature control apparatus for an ink jet printer has a first ink temperature sensor located adjacent but at a spacing from an ink ejection head and a second ink temperature sensor mounted on a heater. The two sensors have an identical temperature coefficient. A voltage supply to the heater is controlled in accordance with a difference between a reference voltage and a sum voltage of outputs of the two sensors. The voltage supply to the heater is further controlled on the basis of an apparent reference voltage, which is a difference between an output voltage of the first sensor and a reference voltage which provides a predetermined temperature, and an output voltage of the second sensor.The two sensors are located before and after the heater. The differential voltage is coupled to the heater after being power-amplified by a power element for output. The power element is mounted on a support member for supporting a filter which is positioned immediately ahead of the first sensor.

Abstract: An improved preheater for use in mass soldering apparatus employing a bank of quartz lamp heaters mounted in parabolic reflectors and including switching means for switching the quartz heaters on and off in response to the presence of a circuit board on a conveyor passing through the preheater.

Abstract: A safety device for an electrical heater having at least one heating element which operates with high current consumption, and two power leads connected to respectively opposite ends of the heating element for connecting the heating element to a power supply.

Abstract: A device (10) for isolating from vibrational and impulse loads a power transfer unit (14) that transfers power from a helicopter electrical system to a plurality of deicing segments on the rotor blades includes a distributor (13) rotating with the rotor blades for distributing power from the power transfer unit (14) to the deicing segments, a housing (11) having an upper cylinder (24) and lower cylinder (23) the latter of which is flexibly secured to the helicopter as by a joint including ball (40), housing 11 substantially isolating the power transfer unit (14) from such loads, and a shaft (12) rotatably engaging the upper cylinder (24) for carrying the distributor (13) in rotation with the rotor blades.

Abstract: A system for monitoring heater elements of electric furnaces so as to identify individual failures, such system comprising an arrangement for detecting the electrical open state of any one of the heater elements, including a current transformer for monitoring current flow; and the capability of monitoring element voltage, such that no element current in the presence of a minimum element voltage is defined as, or taken to be, a failure; further including the provision of a master alarm indication of a defined failure in any of the elements and also an individual alarm indication to indicate which element has failed.

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: A metallic syringe tube is fused to a plastic fitting into which the tube is inserted so that the inner end of the tube contacts the fitting, by clamping the tube between a counterelectrode which acts as an abutment for the inner end of the tube and a clamping jaw which engages the free end of the tube, and applying a resistance heating voltage to the tube between the counterelectrode and a location between the fitting and the clamping jaw for heating at least a portion of the syringe tube inner end in contact with the fitting to the melting temperature of the plastic forming the fitting.

Abstract: A heating arrangement in a fixing station of a printing device has its operation monitored by an arrangement in which a measuring element is disposed in series with the heating element and a switch element. The measuring element is traversed by the heating current and emits a corresponding voltage which is supplied to an amplifier circuit which produces pulse-shaped clock signals as long as the heating current flows through the measuring element and the heating element. The clock signals are supplied to a reset input of a flip-flop whose dynamic input is connected to an oscillator operating at a frequency lower than that of the alternating current so that as long as clock pulses occur, the flip-flop is constantly reset. Therefore, the flip-flop can only be set over a longer interval when no heating current is flowing.

Abstract: A load controller, primarily intended for use in systems having geographically distributed, energy utilizing loads, and employing stored energy heating apparatus. The controller (1, 10) disclosed, in conjunction with a stored energy heater (3, 4), when installed on an energy distribution system having a multiplicity of heaters and controllers, adjusts individual heater storage (3), providing adequate energy for varying heat requirements of individual heaters after a mandatory "off" period (46, 47, 49, 51), thereby greatly reducing the overall peak energy or demand requirements on a central energy source. Alternate embodiments utilize a microprocessor (300) to provide close control of heater storage and improve efficiency. Digital display (307) and a keyboard input are provided for adjusting system constants and evaluating unit operation.

Abstract: A control circuit for a glow plug assembly serving as an engine preheating apparatus is designed so as to effect a temperature control in conformity with the specified position established by selective operation of a key switch having three switching positions, i.e., OFF, ON and START positions. The control circuit comprises a first switch connected between the glow plug assembly and a power source, and a series circuit comprising a second switch connected parallel with the first switch and a resistor.

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 heating device for use in motor vehicles to rapidly heat combustion chambers, exhaust gas sensors, catalyzers and other associated apparatus. A resistive heating element is connected in series with a low-impedance measuring resistor and a switch across a power source, while a resistance bridge is formed with the aid of two further resistors. The diagonal bridge voltages are compared in a comparator whose output actuates a control circuit which operates the heater switch. The heater switch also provides the power for the comparator. In a first interval, constant current is applied to the heating element, while the current is pulsed during a second time interval. The switch control pulses may be provided by a free-running oscillator or one whose pulses are synchronized with the undulations of the engine starter current.

Abstract: A step controller for a water heater having a plurality of individual electrical heating elements changes the number of energized elements to maintain a predetermined minimum temperature. A thermistor sensor monitors the temperature of the water and generates a proportional signal. Preset potentiometers establish set point temperature signal and a dead band signal. The number of "on" elements is related to the difference between the sensed water temperature and the preset water temperature divided by the dead band factor. The heating elements are turned "on" and "off" in a predetermined sequence whenever a change is required. The sequence includes turning on the heating element which has been off for the longest period and turning off the heating element which has been on for the longest period.

Abstract: An apparatus to burn carbon bodies has at least two independently controllable electric resistance heating circuits, at least two temperature sensors and a comparator. Two or more regions of a selected carbon body can be independently heated by the two circuits. The actual temperature of each of those two or more regions can be monitored by corresponding temperature sensors connected to the comparator. The comparator controls each electric resistance heating circuit independently so as to minimize any difference between a preselected temperature and the actual temperature of each region.

Abstract: The invention relates to an electric temperature setback device which is placed in proximate relation to a conventional thermostat and is operatively controlled by a timing device for providing local warmth to the thermostat at pre-determined times and for pre-determined intervals. The setback device includes spades with integral female lamp connectors for arraying a plurality of incandescent lamps in series across an electrical circuit. By so doing, the voltage to each lamp is proportionally reduced, decreasing the filament temperature of each lamp and thereby increasing the amount of heat energy produced proportional to the amount of light energy produced.

Abstract: An energy saving food serving system for rethermalization of the food and for delivery prepared meals to locations remote from the place of preparation, such as to patients to hospitals and nursing homes. The system includes a mobile cart having its own rechargeable power pack that is utilized to propel the cart. The cart has separate bays, each having a tier of racks for carrying individual food serving trays. Each tray has one or more thermally isolated heat transfer devices which are selectably energized when the tray is in place on a rack in the cart. Preferably, each tray has a pair of heaters referred to herein as plate and bowl heaters and adapted to be operated by control means in either a continuous mode of operation or a rethermalization mode of operation.

Abstract: A control circuit for a dishwashing machine to economize its energy consumption and usage. In order to conserve energy, the dishwashing machine has a control system for automatically actuating the components such as the heating elements of the dishwashing machine. The control system can easily be adapted for utilization with many types of existing dishwashing machines, thereby permitting coupling of the control system with commercially available equipment with minimum installation and alteration of machine components.

Abstract: A load controller, primarily intended for use in systems having geographically distributed, energy utilizing loads, and employing stored energy heating apparatus. The controller (1, 10) disclosed, in conjunction with a stored energy heater (3, 4), when installed on an energy distribution system having a multiplicity of heaters and controllers, adjusts individual heater storage (3), providing adequate energy for varying heat requirements of individual heaters after a mandatory "off" period (46, 47, 49, 51), thereby greatly reducing the overall peak energy or demand requirements on a central energy source.

Abstract: A space heater having two heating elements and a motor/fan combination for circulating air over the heating elements to supply heated air to an environment includes a system for controlling the operation of the heating elements and the motor in response to heating requirements of the environment. The control system includes a first circuit for sensing temperature to determine a heating requirement to maintain a desired ambient temperature of the environment, a second circuit for independently activating and deactivating the heating elements in according with the heating requirements determined by the first circuit, and a third circuit for activating, deactivating, and variably controlling the volume of air circulated by the motor/fan in accordance with heating requirements determined by the first circuit. The heater housing includes a main housing portion housing the heating elements, an ambient air intake opening, a heated air exhaust vent, and the motor/fan.

Abstract: A helicopter deicing control system (10) is provided for selectively distributing D.C. electrical power to a plurality of deicing segments (80, 90) on main and tail rotor blades with only two slip-ring assemblies (60 and 61, 62 and 63) for each rotor drive shaft. A power distribution controller (20) receives electrical power from the helicopter's onboard, fixed electrical power system and provides an output signal including power and control D.C. electrical signals of opposite polarities. A distributor (70) receives the output signal from controller (20) and increments a rotary switch (74) upon receipt of a D.C. electrical control signal, and distributes power to the main rotor deicing segment (90) connected to the rotary switch (74) contact then engaged upon the receipt of a D.C. electrical power signal so as to sequentially deliver D.C. electrical power to the desired main rotor deicing segment.

Abstract: A fully automatic system for providing electrical energy to heating and/or hot water systems in facilities serviced by single phase a.c. comprising a three-phase generator driven by single phase a.c. motor means intermittently operated on a load requirement basis wherein the three-phase generator output is normally maintained in an open-circuited condition. Upon controlled load demand, the motor means is energized and the three-phase output is connected to the load only upon achieving optimum operating speed, at which time switch means automatically connects the load to the three-phase output, which on-line condition is maintained until thermostatic control means senses the fact that the system has achieved the desired temperature level at which time the single phase motor means is deenergized.Additional sensing means are provided for protecting the system against damage due to excessive temperature and/or low level conditions.

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: A heating circuit, in particular for electric blankets or pads, comprises a first, heating conductor and a second conductor separated by a material which has an impedance that falls with increasing temperature and/or which will melt in the event of overheating to allow contact between the two conductors. A half-wave rectifier and a thermally-operative circuit interruption means are connected in series with the heating conductor across an AC supply. A resistor is electrically connected to the second conductor such that the resistance and the impedance of said material are connected in series across the supply. The resistor is thermally coupled to the circuit interruption means whereby, in the event of overheating of said material, the drop in the impedance of the material to a reduced or zero value will cause the current through the resistor to increase to heat the resistor, which causes the circuit interruption means to disconnect the circuit from the supply.

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: A process for producing high purity semiconductor materials and metals by ermal decomposition of a gaseous compound of said materials, comprising the steps of arranging conductive carrier bodies in electrical current branches in a multi-phase a.c. system, then passing an equal amount of electrical current through each of the branches so as to heat the carrier bodies to deposition temperature, regulating the current in each of the branches so that the same magnitude of current flows through each branch.

Abstract: An electrical furnace heater construction having electrical heaters carried by a frame and having a current fused drawer-like lead unit movably carried by the frame and having leads for directly and electrically interconnecting to terminals of the heaters when the unit is in one position relative to the frame, the frame having terminals for electrically interconnecting the leads of the unit to power source leads so that the power source leads will be directly and electrically interconnected to the terminals of the heaters by the unit. A temperature responsive power device is carried by the frame and is responsive to the output temperature effect of the electrical heaters, the temperature responsive power device being operatively associated with the unit to move the unit out of the one position thereof to disconnect the leads thereof from the terminals of the heater when the temperature responsive device senses a certain adverse output temperature effect of said electrical heaters.

Abstract: An electric heater means thermally fixes a toner image to a copy sheet to produce a permanent electrostatic copy of an original document. The heater means is normally energized at partial power but is switched to full power by means of microswitches at the inlet and outlet of the heater means which are actuated by the copy sheet while the copy sheet passes through the heater means. The heater means is switched to full power for a shorter length of time during a multiple copy operation than during a single copy operation.

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: Electrical heater construction having a substantially closed housing containing controls therein and having a bracket unit carrying electrical heaters externally thereof, the housing having connectors detachably interconnected to the heaters externally to the housing and electrically interconnecting the heaters to the controls within the housing to be operated thereby. The housing has an externally accessible detachable arrangement and the bracket unit has a detachable arrangement detachably interconnected to the detachable arrangement of the housing in a manner that is accessible externally to the housing whereby the detachable arrangement of the bracket unit can be detached from the detachable arrangement of the housing without access to the interior of the housing so that the heaters can be detached from and/or attached to the housing without requiring the opening of the housing.

Abstract: A method and apparatus is provided for controlling the period or pulse width of pulses applied to exothermic printing elements of a thermal printer to effect printing. Control of the period or pulse width is in response to variations in applied voltage and ambient temperature. A pulse generator for this purpose may include such elements as a varistor, a constant voltage element and a thermistor.

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: The invention is a temperature control circuit which time shares a temperature sensor and related circuit elements in order to switch two control signal outputs, each output at one of two preselected temperatures. In a preferred embodiment, the invention is used to control a self-cleaning oven.

Abstract: An electrical circuit providing for equal power consumption by the included oad elements when selectively energized by independent power sources of differing voltages, through control of the path of current flow through the load elements by rectifiers, the rectifiers being disposed to permit current flow in a direction through the load elements in series when a high voltage source energizes the circuit through one pair of terminals and, without alteration of the circuit, in parallel through the load elements when a low voltage source energizes the circuit through another pair of terminals.

Abstract: An apparatus is disclosed for melting asphalt and for maintaining it in a molten condition without producing by-products harmful to the atmosphere. The asphalt is heated and maintained in a liquid state in an enclosed vessel by transferring heat from a heating means through inner wall portions of the vessel. Air polluting by-products are minimized due to the increased surface area heating the asphalt and the resulting reduced thermal gradient which prevents decomposition of the asphalt. A control system for selectively controlling the heating of the asphalt in a manner which reduces the production of air polluting products is also disclosed.

Abstract: A control system for controlling energization of electrically operated heat generating apparatus included in a multizone electrical heating system. Each of the zones has at least two parallel connected heat generating stages. The second stage heat generating apparatus in any of the zones is prevented from being energized irrespective of the temperature level in the zone when the number of the first stages already activated in each of the zones is greater than a preselected fraction of the total of the first stages.

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: 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: A circuit for connecting to an alternating current electric network having at least one phase a high-power electric heating device, such as a sauna heater, provided with a plurality of electric heating elements. Each phase of the network is evenly divided into a number of separate part leads such that the total number of part leads are arranged in two equal series. A first switch is arranged to simultaneously open and close all of the part leads of both series. A second multipolar switch controlled by a thermostat is adapted to open at least one of the separate part leads of one of the series. Each heating element is connected in circuit with one part lead from each series of part leads. The network may be three phase with the heating elements being delta-connected.

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.