Of Diverse Resistance Characteristics Or Value Patents (Class 219/484)
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Patent number: 10670300Abstract: A tankless water heater includes a heater assembly, a temperature sensor, a flow sensor, a first heating element, a second heating element, and a controller. The heater assembly includes a water inlet, a water outlet, and a heating chamber defining a water flow path between the water inlet and the water outlet. The temperature sensor measures the temperature of water flowing through the heating chamber. The flow sensor measures a flow condition of water within the heating chamber. The first and second heating elements are located in the heating chamber and include first and second wattages, respectively. The second wattage is different from the first wattage. The controller is coupled to the first and second heating elements and the temperature and flow sensors. The controller is configured to regulate the amount of electrical current flowing through the first and second heating elements in response to the flow condition.Type: GrantFiled: December 13, 2016Date of Patent: June 2, 2020Assignee: Choronomite Laboratories, Inc.Inventor: Edward Vincent Fabrizio
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Patent number: 10132525Abstract: A flow-through fluid heater comprises: a high thermal conductivity conduit-defining body shaped to provide a conduit that extends between an inlet port and an outlet port; one or more heating elements connected to the body for providing heat to the body, thereby permitting the body to provide heat to fluid flowing through the conduit; a temperature sensor connected to sense a measured temperature indicative of a temperature of the fluid in a vicinity of the temperature sensor; one or more flow rate sensors for sensing a measured flow rate of the fluid through the conduit; and a controller connected to receive signals from the temperature sensor and the flow rate sensors, the controller configured to control an amount of heat energy imparted to the fluid during a period that the fluid is resident in the conduit between the inlet port and the outlet port based at least in part on the measured temperature and the measured flow rate.Type: GrantFiled: November 22, 2016Date of Patent: November 20, 2018Inventor: Peter Klein
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Patent number: 8965187Abstract: A heating system for a fluid pipe system in which at least one electric heating element (RL) is assigned to at least one fluid line, said heating element, in order to apply a predetermined heating output to the fluid line, being provided with an electric operating voltage (UB) that is reduced compared to the supply voltage (U).Type: GrantFiled: March 4, 2010Date of Patent: February 24, 2015Assignee: VOSS Automotive GmbHInventors: Olav Borgmeier, Tobias Etscheid, Reiner Mitterer, Thomas Schüler
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Publication number: 20150028019Abstract: A warm-up apparatus for a vehicle including a system which charges a battery by using an external power supply is provided. The warm-up apparatus includes a heater for warming up, a current detector, a voltage detector and a resistance changer. The heater is mounted in the vehicle and produces heat by receiving electric power from the external power supply. The current detector detects an allowable current value of the external power supply. The voltage detector detects an output voltage value of the external power supply. The resistance changer changes an electric resistance value of the heater based on the allowable current value detected by the current detector and the output voltage value detected by the voltage detector.Type: ApplicationFiled: July 28, 2014Publication date: January 29, 2015Inventor: Makoto KAMACHI
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Patent number: 8909033Abstract: A method is provided for interconnecting a single electrical heating element of a hot water heater to first and second AC electrical power sources. Typically, these first and second AC electrical power sources include a utility provided electrical power source and a renewable power source that generates AC power from DC power. The method includes operating a controller that selectively connects and disconnects the first and second power sources. If sufficient electrical power is available from the renewable power source, the utility provided electrical power source may be disconnected to preferentially utilize renewable energy.Type: GrantFiled: April 9, 2012Date of Patent: December 9, 2014Inventor: David Kreutzman
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Patent number: 8809747Abstract: A method of operating a heating plate for a substrate support assembly used to support a semiconductor substrate in a semiconductor processing apparatus, wherein the heating plate comprises power supply lines and power return lines and respective heater zone connected between every pair of power supply line and power return line. The method reduces maximum currents carried by the power supply lines and power return lines by temporally spreading current pulses for powering the heater zones.Type: GrantFiled: April 13, 2012Date of Patent: August 19, 2014Assignee: Lam Research CorporationInventors: John Pease, Neil Benjamin
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Patent number: 8693854Abstract: A uniform voltage is applied to loads even to other than a multiple of three loads made of heating lamps connected in parallel to each other, without causing any burden on a primary side. The number of loads is divided into a multiple of three and a multiple of two. A three-phase AC voltage is applied to three primary windings, which are connected as a Y-connection or a ?-connection. Secondary windings, which are each magnetically coupled to a primary winding of a plurality of three-phase transformers and have the same number of turns, are connected with the multiple of three loads.Type: GrantFiled: August 26, 2011Date of Patent: April 8, 2014Assignee: Ulvac, Inc.Inventors: Tsuyoshi Yoshimoto, Katsumi Yamane, Tetsuhiro Ohno, Takahiro Mizoguchi
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Patent number: 8481898Abstract: Systems and methods for PTC materials are described. In one example, a PTC constant wattage heater provides two or more self regulating heating modes. The PTC constant wattage heater may provide self regulating temperature and current control at lower expense.Type: GrantFiled: May 27, 2011Date of Patent: July 9, 2013Inventor: Robert Parker
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Patent number: 8269513Abstract: The invention relates to a method for monitoring an electrical heating apparatus and to a corresponding apparatus. The electrical heating apparatus has at least one heating element. A measured value, which is dependent on the resistance and/or the inductance of the electrical heating element, is measured, the measurement being carried out by means of the measured value being sampled. Owing to the use of sampled values, the measurement process can be shortened.Type: GrantFiled: August 11, 2006Date of Patent: September 18, 2012Assignee: Siemens AktiengesellschaftInventors: Berthold Palm, Günter Grommes
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Patent number: 8138453Abstract: A electric oven is provided that includes a body, a cooking chamber located within the body for receiving food, the cooking chamber having an upper surface, a lower surface, and a rear surface joining the upper surface to the lower surface, at least one of a convection heater located at the rear surface of the cooking chamber and a bake heater located at the lower surface of the cooking chamber, and at least two broil heaters located at the upper surface of the cooking chamber, each of the at least two broil heaters being individually operable. Methods for preheating the electric oven are also provided.Type: GrantFiled: August 22, 2008Date of Patent: March 20, 2012Assignee: LG Electronics Inc.Inventors: Jae Kyung Yang, Hyeun Sik Nam, Dong Seong Kwag, Seong Ho Cho, Wan Soo Kim
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Patent number: 8058590Abstract: A cooking and storage system comprises a refrigeration device, a cooking device and controller for controlling the cooking device, and the refrigeration device provides to the controller temperature information relating to the temperature within the refrigeration device.Type: GrantFiled: May 30, 2007Date of Patent: November 15, 2011Assignee: Merrychef LimitedInventors: Nigel Thorneywork, Andrew Brown, David Crayfourd
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Patent number: 8044326Abstract: A steam cooking apparatus having a steam generating device that generates steam to be fed to a heating chamber and a vapor heating heater that heats the steam generated by the steam generating device to provide superheated steam. The steam cooking apparatus includes a first heating mode using the superheated steam obtained from the vapor heating heater and a second heating mode using hot air or radiation heat obtained by using the vapor heating heater without use of the steam generating device so that the second heating mode produces heat without a supply of steam.Type: GrantFiled: July 10, 2009Date of Patent: October 25, 2011Assignee: Sharp Kabushiki KaishaInventors: Yuzi Ando, Yuko Nakajima, Mari Terada, Rika Nozawa, Noriko Ohashi
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Patent number: 7993124Abstract: To fabricate a composite item, an infrared heat source is energized and a composite material is dispensed. The composite material includes a reinforcement and a resin. In addition, the composite material is applied to a substrate of previously applied composite material. The infrared heat source is configured to emit a wavelength of electromagnetic radiation that is absorbed by the resin to a relatively greater extent than the wavelength of electromagnetic radiation is absorbed by the reinforcement.Type: GrantFiled: December 28, 2006Date of Patent: August 9, 2011Assignee: The Boeing CompanyInventors: Spencer G. Nelson, Robert A. Kisch, Peter Vogeli, Richard Calawa
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Patent number: 7800025Abstract: The present invention provides a micro-control unit a RC oscillator for generating a reference clock, a plurality of touch switches for generating a transition signal indicating one of the touch switches being touched by human beings, a plurality of analog switches coupled to the touch switches for controlling transmission of the transition signal and a plurality of counters for counting time, all of the counters stop counting when one of the counters overflows and content of all counters being read, wherein ON/OFF of the analog switches controlled by a software.Type: GrantFiled: June 4, 2007Date of Patent: September 21, 2010Assignee: Holtek Semiconductor Inc.Inventors: Wen-Liang Liu, Chin-Hung Yang
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Patent number: 7642488Abstract: An electric oven includes a cooking cavity surrounded by an inner case and being openable by a door; a first heater for heating the cooking cavity; at least one supplemental heater for heating the cooking cavity; and a controller operating the first heater to generate heat when starting cooking and selectively operating the at least one supplemental heater during cooking.Type: GrantFiled: April 28, 2006Date of Patent: January 5, 2010Assignee: LG Electronics Inc.Inventors: Hag Sin Kim, Myeong Yeol Kang
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Patent number: 7619181Abstract: A control system suitable for use with a bathing unit system having a water receptacle is provided. The control system comprises a heating module, a power source and a controller in communication with the heating module and the power source. The power source includes an energy storage member for storing energy collected from a solar panel, and is operative for supplying power generated from solar energy to the heating module. The controller is operative for causing the power source to supply power to the heating module at least in part based on first information derived from a temperature of the water within the water receptacle and second information derived from a condition associated with the power source. The controller is further operative for selecting between a first power source and a second power source for supplying power to the heating module.Type: GrantFiled: May 2, 2006Date of Patent: November 17, 2009Assignee: Gecko Alliance Group Inc.Inventor: Michel Authier
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Patent number: 7589299Abstract: In one aspect, a cooktop heating system that include a first cooktop heating element, a second cooktop heating element, and an interface device. The system also includes a controller for selectively associating the interface device with any one or both of the first cooktop heating element and the second cooktop heating element. In another aspect, the system includes at least one cooktop heating element, a potentiometer, and controller arrangement operatively connected between the potentiometer and the at least one cooktop heating element to determine heating of the at least one cooktop heating element responsive to the input provided by the potentiometer and control power provision to the at least one cooktop heating element responsive to the determination.Type: GrantFiled: November 17, 2006Date of Patent: September 15, 2009Assignee: Electrolux Home Products, Inc.Inventors: Gary Fisher, Chris Ray Blackson
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Patent number: 7495194Abstract: A heating apparatus includes a plurality of heating means that heat a heated object, a temperature measuring means that measures temperatures of some of the plurality of heating means, a heated object information storing means that stores, in a coordinate manner, heated object identification names, target heating temperatures at the heating means, and sets of heating ratios respectively assigned to the heating means, a heating information storage means that defines a relationship between temperatures during heating of the heating means up to the target heating temperatures and heating intensities at the temperatures, a heated object identification name obtaining means that obtains one of the heated object identification names, a heated object information reading-out means that reads out one of the target heating temperatures and one of the sets of heating ratios respectively assigned to the plurality of heating means, corresponding to the heated object identification name from the heated object information stType: GrantFiled: November 10, 2006Date of Patent: February 24, 2009Assignee: Asano Laboratories Co., Ltd.Inventors: Toshihiro Takai, Yasuyoshi Ohashi, Kazushi Hayashi
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Publication number: 20080302783Abstract: In one embodiment, a test board includes a plurality of socket locations each to receive a corresponding burn-in socket which in turn is to receive a semiconductor device under test (DUT). Each of the socket locations includes a heating element embedded within the test board, which may be used to provide thermal conduction to the DUT during a burn-in test. Other embodiments are described and claimed.Type: ApplicationFiled: June 8, 2007Publication date: December 11, 2008Inventors: Anthony Yeh Chiing Wong, Christopher Wade Ackerman, James C. Shipley, Hon Lee Kon
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Patent number: 7076324Abstract: An embodiment of the present invention uses an on-board microcontroller of a household appliance to receive signals from a directionless encoder attached to a knob for receiving user input and processing the signals from the direction encoder according to a control algorithm. The microcontroller may increase the output to an electric heating element on the appliance based on a variety of criteria, including either direction of rotation, current heating element setting, or a change in directional rotation. Alternatively, or in addition, the microcontroller may provide various types of graduated visual or audible feedback to the user.Type: GrantFiled: August 12, 2004Date of Patent: July 11, 2006Assignee: K.G.O. North America, Inc.Inventors: Alton Harkcom, Craig E. Bryan, Joerg Clemens
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Patent number: 6888109Abstract: A heating device for a gas sensor, in particular for use in the exhaust gas analysis of internal combustion engines, including a heating element having an electrical resistor layer. The heating element is embedded in a first insulation which in turn is surrounded, at least in part, by a second insulation. The first and the second insulation have different porosities.Type: GrantFiled: November 13, 2001Date of Patent: May 3, 2005Assignee: Robert Bosch GmbHInventors: Detlef Heimann, Torsten Handler, Lothar Diehl, Dieter Lindauer, Dietmar Seizinger
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Patent number: 6872922Abstract: A method for operating a multi-stage electrical heater comprised of several heating elements. In conventional multi-stage electrical heaters, the resistance value of the individual heating elements scatters. In order that the individual heating elements emit the same power, specifically the required nominal power, despite the scattered resistance values, the voltage on the individual heating elements is separately regulated down to the required nominal power, proceeding from a maximum electrical resistance of the individual heating elements, at which the entire applied operating voltage yields the nominal power of the individual heating elements required for operation.Type: GrantFiled: September 24, 2002Date of Patent: March 29, 2005Assignee: Beru AGInventor: Günther Uhl
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Publication number: 20040108309Abstract: A method of reducing a fusing apparatus recovery time from a low energy-saver mode temperature back up to a high fusing temperature, the method includes supplying power to a heated member of the fusing apparatus to warm the fusing apparatus from a start up temperature to the high fusing temperature from a primary power supply; and supplying full power to the heated member of the fusing apparatus to warm the fusing apparatus from a start up temperature to the high fusing temperature from a battery power supply.Type: ApplicationFiled: December 10, 2002Publication date: June 10, 2004Applicant: Xerox CorporationInventor: Neil J. Dempsey
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Publication number: 20040060922Abstract: A composite cooking machine includes a plurality of switches which are connected in series with a plurality of component cooking machines, between a circuit breaker in a home and the component cooking machines, respectively, to selectively supply power to the component cooking machines. A control unit of the composite cooking machine controls the switches so as to supply the power to only one of the component cooking machines, without responding to a key signal for another one of the component cooking machines, where a cooking operation performed by the one component cooking machine has not been completed. Therefore, the composite cooking machine does not allow simultaneous operations of the component cooking machines, and prevents unnecessary operations of the circuit breaker. Accordingly, the reliability of the composite cooking machine is improved.Type: ApplicationFiled: February 25, 2003Publication date: April 1, 2004Applicant: SAMSUNG ELECTRONICS CO., LTD.Inventor: Jeon-Hong Kang
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Publication number: 20030127449Abstract: A device and method for controlling a heater of a drying machine is disclosed, which includes a plurality of switches, each switch having a plurality of input terminals being supplied with different input voltages and an output terminal, and each switch connecting any one of the input terminals with the output terminal according to a switching control signal, and a heater connected to the output terminal of each switch and varying its temperature according to the input voltage being supplied thereto.Type: ApplicationFiled: November 27, 2002Publication date: July 10, 2003Inventor: Soon Jo Lee
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Publication number: 20030071032Abstract: A heating system 25 has a main heating element 3 generating heat be supplying an electric power supplied and having a heating surface 4a for heating an object, auxiliary heating elements 5A to 5D generating heat by supplying an electric power, and a main power source 1 for supplying the to the main heating element 3. The system 25 further has an auxiliary power source 2 supplying the power to the auxiliary heating elements 5A to 5D, and a power source controller 2 for controlling the power supplied to the main heating element and the power supplied to the auxiliary heating elements respectively and independently. The power supplied from the main power source 1 to the main heating element 3 is controlled by the controller 2 within a first power range. The power supplied from the auxiliary power source to the auxiliary heating elements is controlled by the controller 2 within a second power range.Type: ApplicationFiled: September 17, 2002Publication date: April 17, 2003Applicant: NGK Insulators, Ltd.Inventors: Shinji Yamaguchi, Yoshinobu Goto, Hisakazu Okajima, Yutaka Unno
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Publication number: 20020088794Abstract: The present invention provides a controller for a heating unit. The heating unit is capable of generating heat to a utensil and has a temperature sensor, a heating element, and a cooking surface. The controller has a means for measuring a temperature of a cavity within the heating unit, a means for controlling the application of power to the heating element, and a means for determining whether to control the application of power to the heating element in an overdrive state based on a type of utensil that is located on the heating unit. The present invention also includes methods of operating the controller and the heating unit.Type: ApplicationFiled: January 9, 2001Publication date: July 11, 2002Inventors: Edward A. Nelson, Gregory A. Peterson
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Patent number: 5796076Abstract: A sauna heater control having a plurality of electrical heater elements for heating a sauna chamber, an alternating current heater power circuit, a half-wave rectifier for selective inclusion in the alternating current heater power circuit, a plurality of circuits for connecting the electrical heater elements and the half-wave rectifier in various conductive pathways in the alternating current heater power circuit, and a switch for switching the electrical heater elements and the half-wave rectifier between the various conductive pathways.Type: GrantFiled: October 13, 1995Date of Patent: August 18, 1998Inventor: Yoshihiko Azuma
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Patent number: 5748429Abstract: A self-checking temperature sensing circuit in which temperature sensitivity is provided by first and second resistive elements having positive and negative temperature coefficients respectively. The resistive elements are connected in parallel current paths, one of which includes a diode for allowing only unidirectional current flow. The resistances of the restrictive elements are determined by a circuit which periodically reverses the polarity of a voltage applied across the parallel paths.Type: GrantFiled: September 9, 1996Date of Patent: May 5, 1998Assignee: Honeywell Inc.Inventor: Scott M. Peterson
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Patent number: 5352862Abstract: A pliable high wattage electrical resistance contact heater which is operable at two wattage densities and which includes a first heating element which is thermostatically controlled so as to activate at predetermined ambient and/or surface temperatures and a second overlapping heating element which is continuously activated when the heater is connected to a source of electrical power supply.Type: GrantFiled: November 9, 1992Date of Patent: October 4, 1994Assignee: Five Star Manufacturing CompanyInventor: George A. Barr
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Patent number: 4887092Abstract: In a prior art thermal printing method, the heating elements of a thermal printing head are driven in such fashion that the temperature of each and every individual heating element is first measured individually and successively before this heating element is charged with a current pulse whose intensity of current is dimensioned dependent on the measured temperature. In order to increase the printing speed, the temperatures of all heating elements (R1 . . . Rn) are first successively measured in the novel method fo the present invention in every drive cycle and are extrapolated to isochronic cooling temperature values dependent on the cooling characteristic of the heating elements (R1 . . . Rn). The heating elements (R1 . . . Rn) are then charged with current pulses whose pulse durations are individually dimensioned for every heating element (R1 . . . Rn) dependent on the cooling temperature value calculated for this heating element (R1 . . . Rn).Type: GrantFiled: December 7, 1988Date of Patent: December 12, 1989Assignee: Siemens AktiengesellschaftInventors: Wolfgang Pekruhn, Ralf Kaiser, Hartmut Kirchhoff
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Patent number: 4717924Abstract: A control system for a thermal print head includes means for regulating the firing of the print elements with the proper pulse width to compensate for increasing substrate temperature. The control circuit is divided into two separate circuits--the driving circuit for turning the print elements on and off, and the decision-making circuit which executes the substrate temperature coding and control codes and sends control signals to the driving circuit. Three types of temperature compensation are utilized in the control program. A tailored pulse width is used for each bank of the print elements to compensate for various element resistances. As the print head shuttles across the record medium, the pulse width is reduced for each horizontal dot position. The pulse width also is reduced for each line printed in the format. The system may be used for either direct thermal or thermal transfer printing with both full and half dot spacing and single or double width characters.Type: GrantFiled: August 18, 1986Date of Patent: January 5, 1988Assignee: NCR CorporationInventors: Richard G. Bangs, Sik P. Kwan
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Patent number: 4713525Abstract: A microcomputer operates in response to user selected flow rate and water temperature inputs to calculate the temperature difference between the cold water input and the hot water delivery output from a multisection continuous flow electric water heater wherein a plurality of electric resistance heater elements contained therein provide 5.degree. F. temperature increase increments each, while one heater element is comprised of three sub-sections, two of which provide 2.degree. F. temperature increments and one section provides a 1.degree. F. temperature increase increment. The microcomputer constantly monitors the water temperature difference and controls activation of the required heater elements or element sub-sections to heat the water to a selected delivery temperature with an output solenoid being additionally controlled to provide delivery at a selected flow rate.Type: GrantFiled: July 23, 1986Date of Patent: December 15, 1987Assignee: Kowah, Inc.Inventor: Calvin W. Eastep
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Patent number: 4638147Abstract: A through-flow electric water heater has a cannister through which water to be heated flows and in which are disposed a first heating means comprising a plurality of electric heating elements and second heating means comprising at least one electric heating element. A control unit comprising a microprocessor receives a first input signal from a flow sensor and a temperature sensor which sense, respectively, the flow rate and temperature of the water flowing into the cannister and switches the plurality of heating elements of the first heating means on and off in different combination to achieve different heating levels and adjusts the level of heat dissipated by burst firing the at least one heating element of the second heating means to achieve a desired total heating level.Type: GrantFiled: October 17, 1984Date of Patent: January 20, 1987Inventors: Anthony Dytch, Andrew Keatley, William Wright
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Patent number: 4538049Abstract: A new and improved electric toaster oven is disclosed, wherein the heating ratio between upper and lower heat sources can be readily changed to suit the different requirements of the food item being cooked, while the rate at which the total heat is applied to the food item remains substantially constant throughout.Type: GrantFiled: April 3, 1984Date of Patent: August 27, 1985Assignee: Black & Decker, Inc.Inventor: William D. Ryckman, Jr.
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Patent number: 4513196Abstract: An electrically heatable self-defrosting windshield has a transparent panel, two low-resistance groups of wires embedded in the panel and defining a primary zone requiring rapid heating, and at least one high-resistance group of wires embedded in the panel and defining a secondary zone adjacent the primary zone and not requiring rapid heating. A switch connected to the wire groups and to an electric power source is movable between a fast-heat position connecting the two low-resistance groups in parallel with each other across the source and effectively disconnecting the high-resistance wires, and a slow-heat position connecting the two low-resistance groups in series with each other and jointly in parallel with the high-resistance groups across the source. The total resistance of the groups in the fast-heat position is generally the same as in the slow-heat position.Type: GrantFiled: July 14, 1983Date of Patent: April 23, 1985Assignee: Flachglas AktiengesellschaftInventors: Lutz Bartelsen, Hans-Cristoph Neuendorf
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Patent number: 4464564Abstract: A current controller interface accepts a variable voltage at its input and develops a current at its output which corresponds directly with the input variable voltage. Its apparatus is usually associated with a program controller as an input and a microscope which has a heated element as the output. The apparatus uses a control circuit which is coupled to a controllable resistance semiconductor device, which device has an output which varies in resistance in accordance with variation in input current. The output of the variable resistance device is coupled in series with the heating coil of the microscope, the power supply and current sensing resistor. The resistor develops a feedback voltage which is applied to the control circuit so that when a change in voltage is applied to the input the output from the current sensing element will change until it balances the current being applied at the input. When the balance occurs, no further change in output current will occur.Type: GrantFiled: October 27, 1982Date of Patent: August 7, 1984Assignee: Conoco Inc.Inventors: Wiley E. Zimmerman, Jimmy R. Alexander, Don E. Boles, Rhea W. Bockhorst
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Patent number: 4352707Abstract: A composite repair device including a plurality of resistive heating zones, each having independent temperature and rate of temperature rise controls, to compensate for the greater heat loss at the outer areas of a composite patch.Type: GrantFiled: April 23, 1981Date of Patent: October 5, 1982Assignee: Grumman Aerospace CorporationInventors: Leonard M. Wengler, Harold J. Wicker, Michael J. Masica, Jr.
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Patent number: 4088869Abstract: A hair dryer includes a casing having an air inlet and an air exit defining an exit plane. A motor driven fan propels air through the casing between the air inlet and exit. Plural wattage electric heating elements are disposed in a heater box in the casing for heating air to a selected temperature for discharge through the casing air exit. A thermostat, positioned downstream of the heating elements substantially centrally across the exit plane of the casing and disposed substantially in the exit plane, is connected in series circuit with at least some of the heating elements. The thermostat rapidly senses the air temperature at the air exit and disconnects the connected heating elements.Type: GrantFiled: September 8, 1975Date of Patent: May 9, 1978Assignee: General Electric CompanyInventor: Esko J. Nopanen
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Patent number: 4066868Abstract: The disclosed invention describes an apparatus and method for bringing a system having high interactive portions to a predetermined temperature distribution. The invention includes a difference controller which provides, through two separate drivers, a fixed total amount of energy to the system being controlled. If the system being controlled also has a long cycle time, second and third temperature controllers may be used to bring the system to the equilibrium temperature with a minimum amount of overshoot. The invention is particularly advantageous when used in connection with a high pressure, high temperature vessel useful in growing quartz crystals.Type: GrantFiled: July 7, 1975Date of Patent: January 3, 1978Assignee: National Forge CompanyInventors: Donald E. Witkin, Arnold G. Bowles