Abstract: A fluid flow rate measuring apparatus having a thermistor exposed to a flow of fluid and a driver circuit operable in an initial constant-voltage mode, in which it applies a substantially constant voltage across the thermistor, and a subsequent constant-current mode, in which it applies a substantially constant current through the thermistor, such current corresponding to the current level at the end of the constant-voltage mode. A voltage sensor measures the resultant voltage drop across the thermistor, which is a direct measurement of the fluid flow rate and which is substantially insensitive to variations in ambient temperature.

Abstract: A heater for heating fluid is shown having a plurality of self-regulating electrical resistance heater elements 22 placed in electrically and thermally conductive relationship with heat transfer members 20, 120. The heat transfer members are each configured to form a plurality of fluid receiving channels so that when placed in a fluid stream heat generated by the heater elements will be dissipated to the fluid through the heat transfer members. Additionally, thermally conductive grease is used between the heater elements 22 and heat transfer member 20, 120 to better transfer the heat. The heater elements are arranged in groups with at least two heater elements in a group electrically connected in series and the groups electrically connected in parallel.

Abstract: A semiconductor body (10) has a first region (13) of one formed a semiconductor device (Rx) having a resistance which varies with temperature. The semiconductor device (Rx) is formed by a second region (14) of the opposite conductivity type formed within the first region (13) and a third region (15) of the one conductivity type formed within the second region (14), with first and second electrodes (16) and (17) being spaced apart on the third region (15) so that a resistive path is provided by the third region (15) between the first and second electrodes (16 and 17) and a reference electrode (18) connecting the second region (14) to a reference potential.

Abstract: A heat generator is formed to quickly raise the temperature of an object to be heated to a target level and then maintain the temperature of the object at the target level. The heat generator includes a high output heating element for heating the object to be heated, a temperature controller which is thermally coupled with the object and connected in series with the high output heating element for deenergizing the high output heating element when the temperature of the object exceeds the target level while energizing the high output heating element when the temperature of the object is reduced from the target level by a prescribed value, and a positive temperature coefficient thermistor which is thermally coupled with the object and connected in parallel with the high output heating element and the temperature controller, the thermistor having a Curie point set so as to produce an output capable of maintaining the object at the target temperature even when the high output heating element is deenergized.

Abstract: Heating pads using positive temperature coefficient (PTC) resistance material are subject to fire risk if one of the conductor wires between which the PTC material extends should break and produce an electric arc. Protection by fuse and a fuse-blowing circuit responsive to fire detection must allow for an immense inrush of current when the cold pad is turned on. A heat setting control using a microprocessor can reduce the fuse rating by chopping the a.c. heating current for a short start-up period following with full-on feed until the heat setting is reached. The presence of a microprocessor allows response to a safety circuit that detects a break in a heater feed or return conductor before much excess heat develops, so that the microprocessor can turn off the heater switch. That response is so quick that it can be confirmed by repeated detection after very short pauses before the heater switch (a triac) is turned off.

Abstract: Heating pads using positive temperature coefficient (PTC) resistance material are subject to fire risk if one of the conductor wires between which the PTC material extends should break and produce an electric arc. Protection by fuse and a fuse-blowing circuit responsive to fire detection must allow for an immense inrush of current when the cold pad is turned on. A heat setting control using a microprocessor can reduce the fuse rating by chopping the a.c. heating current for a short start-up period following with full-on feed until the heat setting is reached. The presence of a microprocessor allows response to a safety circuit that detects a break in a heater feed or return conductor before much excess heat develops, so that the microprocessor can turn off the heater switch. That response is so quick that it can be confirmed by repeated detection after very short pauses before the heater switch (a triac) is turned off.

Abstract: A heater assembly for electrically heating fuel subsequent to its being sprayed from a fuel injector has a body that receives an end portion of the fuel injector and a heating structure. The heating structure includes a heat sink formed from an electrically and thermally conductive metal or metal alloy having an opening formed therein for receiving fuel sprayed from the nozzle of the fuel injector, one or more integrally formed flats on an exterior surface of the heat sink, and one or more substantially flat heating elements mounted in heat conducting relation to the flats. The substantially flat heating elements may be formed from Positive Temperature Coefficient material. An electric supply is provided for powering the one or more heating elements and a control device is provided for regulating the power supplied from the electric supply.

Abstract: A PTC semiconductor heating device includes: two half shells combinable for forming a housing of the semiconductor heating device, a plurality of linear arrays of PTC semiconductor heating elements parallelly mounted in the housing with each linear array containing a plurality of PTC semiconductor heating elements longitudinally disposed in a side-by-side linear arrangement in said housing and each linear array of PTC heating elements being sandwiched in between every two neighboring thermally and electrically conducting units respectively connected to two poles of a power source and longitudinally juxtapositionally mounted in the housing each thermally and electrically conducting unit including a corrugated fin plate formed with a plurality of continuous square waves and clamped by a pair of conducting plates, and a plurality of resilient embedding plates each embedding plate resiliently inserted in between every two neighboring thermally and electrically conducting units for firmly tensioning, packing and r

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: A new type of heater support structure for YIG sphere support rods used in high frequency YIG oscillators and filters. The heater structure employs a rubber O-ring stretched around the perimeter or one or more rubber rods threaded through holes perpendicular to the rod support holes in the heater block and positioned such that the rods deform the rubber and are thereby pressed against a surface of the rod support hole. In alternative embodiments, V-grooves are formed in the heater block to support the rods. The heater block is brass in some embodiments and barium titanate in others. For brass blocks, the rods are beryllium oxide For barium titanate heater blocks, the rods can be either beryllium oxide or barium titanate.

Abstract: A positive temperature coefficient composition including a monomeric crystalline organic material is disclosed having a preselected switching temperature below about 150.degree. Fahrenheit. Devices incorporating same and related method of manufacture are set forth. The material includes a continuous, single phase solution of a polymer, for providing cohesion and flexibility to the positive temperature coefficient material.

Abstract: A control system, a control device therefor and methods of making the same are provided, the control system comprising a source of energy, an output producing unit that uses the energy to produce the output thereof, a control device having control structure for interconnecting the source of energy to the unit, the control device having a rotatable shaft that sets the control structure in different positions thereof in relation to the rotational set position of the shaft from an "off" position thereof, the control structure having the amount of the energy passing therethrough from the source to the unit being different for each set position thereof, indicating structure operatively associated with the shaft for visually indicating the set position of the shaft and, thus, the amount of energy being fed by the control structure to the unit, and sensing structure operatively associated with the shaft that senses the set position of the shaft and electronically displays that sensed position of the shaft whereby th

Abstract: A heat cooking apparatus arranged to cook a food article through heating by projecting microwave energy generated by a magnetron and heat rays produced by an electric heating unit onto the food article placed in a heating chamber, and including a light source for projecting visible light rays onto the food article, a photo-detector for detecting a light amount of the visible light rays reflected by the food article, a temperature sensor for detecting temperature within the heating chamber, and a control unit which monitors variation with time of detection signals from the photo-detector and the temperature sensor during heating of the food article by the electric heating unit and controls to complete the heating of the electric heating unit by judging that the heating is to be terminated when the detection signal of the photo-detector is reduced by a predetermined value from a maximum value, and the detection signal of the temperature sensor is increased by a predetermined value from an initial value.

Abstract: A glow plug for an air compressing internal combustion engine of the type having a tube which is closed at one end and connected to a plug housing on an opposite end with a wire filemant-like resistance element disposed in an insulating material within the tube and formed two series-connected resistance filaments, of which the rear resistance filament, serves as a regulating filament, having a higher positive temperature resistance coefficient than the front resistance filament, which serves as a heating filament, is improved so as to enable the heating up time to be reduced without adversely impacting upon the effective life of the glow plug. In accordance with various embodiments, this result is achieved through the use of, for example, special alloys for the material of the regulating filament which have a resitance at 1000.degree. C. that is greater than their resistance at 20.degree. C. by a resistance ratio over about 7.5:1, and preferably greater than 12:1, and in particular, about 14:1.

Abstract: A heater for a water bed including an elongated PTC cable having conductors by a carbon loaded polymer material with the cable being tortuously disposed with closely spaced parallel lengths supported in a coplanar sandwiched relationship by adhesively coated sheets of polyester and aluminum, the sheets and cable being sealed in a polyvinyl chloride envelope.

Abstract: A heated comfort product such as an electrical blanket having an elongate electrical resistance element is connected in a particular manner to an AC power line by connecting the ends of conductors used in the element at a common end to respective AC power lines so as to achieve reduced or non-detectable electromagnetic and/or electrostatic radiating fields from the comfort product.

Abstract: This invention relates to a self-limiting electrical heating element comprising resistance components having a positive temperature coefficient and a zero temperature coefficient, arranged in a layered structure with two electrodes placed diagonally within or in contact with two ZTC layers separated by a PTC layer.

Abstract: PTC Devices and PTC compositions described herein comprise a blend of at least three carbon blacks as a particulate filler in a fluorinated polymer to achieve a substantial PTC effect and operability over a wide temperature range including temperatures prevailing in a steam environment. Two of the carbon blacks are selected to impart PTC effect to the composition. The third carbon black is selected to adjust the resistive properties of the composition into the range of commercial usage and to impart uniformity of the resistive properties within a given batch as well as from one batch of mix to the next.

Abstract: An apparatus for heating gases, particularly air, with a heating unit having a mounting part, at least one PTC component, at least one insulating frame part surrounding the latter, at least one contact plate and at least one insulating support. The PTC component is surrounded by the frame part being inserted in the mounting part and on at least one flat side rests a contact plate and is covered by an insulating support. Heat emission lamellas are mounted in a clamping manner on the heating unit to ensure an effective heat emission to the surrounding air or gas.

Abstract: An elongated flexible heater strip is provided having a transmission line section and a heater section employing a high mu material to control temperature at the Curie temperature of the high mu material; the above elements and a return buss being confined in a conductive sheath having a plurality of transverse slots to render the strap flexible, so that it may be cinched about a member to be heated; a strip of conductive material, such as copper, extending at least along the transmission line section interiorly of said sheath to reduce the resistance thereof and increase the current carrying capacity of the strap.

Abstract: For the better handling of PTC components during the assembly of a corresponding heating arrangement, in the case of a holding part for PTC components with an insulating frame and at least one contact plate, a contact plate is firmly connected to the insulating frame (12).

Abstract: An electric heating element is proposed, which has a contact unit formed from at least one PTC component and contact plates resting on either side thereof and a casing, whereby for ensuring a good contact pressure in the end product in the unpressed state of the heating element the contact plates (12, 13) are curved and rest with their convex side on the PTC components (14), the casing (2) is made from dimensionally stable light metal and in the unpressed state has an inner wall (17, 18) with a finite radius of curvature (r1) facing in convex manner the contact arrangement (12, 13, 14) and which is larger than the radius of curvature (r2) of contact plates (12, 13).

Abstract: A layer of conductive polymer having a positive temperature coefficient (PTC) of resistivity and a unifrom thickness, is laminated between copper foils to form a composite sheet which is die-cut to form a planar heater assembly. A small portion of the laminated heater assembly is bent laterally outwardly to form a connector tab, and the heater assembly is adhesively bonded to the back surface of a rear view mirror having a corresponding shape and size. A plastic case supports the mirror and spring-like electrical contact terminals which engage the copper foils on the tab, and the terminals are connected to electrical conductors to provide for heating the entire mirror according to variations in temperature on the mirror surface. The tab may be lanced from the heater assembly or be formed from a projecting edge portion, and the heater assembly may be enclosed within a flexible plastic film to provide resistance to chemical corrosion.

Abstract: A building block-like PTC thermistor heating element is disclosed which comprises a ceramic semiconductor body having a positive temperature coefficient of resistance. The partition walls of the building block-like ceramic body provide the passages of the air flow. Ohmic electrodes are deposited on the opposite side of the major surface of the ceramic body so that when connected to an electrical source the electrical current flows across the partition walls in a direction normal to the axis of the air flow. The building block-like thermistor is very easy to fabricate and is very strong in structure so that high yield and improved mechanical strength can be achieved.

Abstract: An improved bushing controller is shown which utilizes an auxiliary transformer in each of the variable impedance circuits in the controller and the bushing tha the controller is connected to increase the current capability of the controller by a significant percentage. Improved performance of fiber glass bushings producing multiple forming packages is realized.

Abstract: A conductive polymer composition which exhibits PTC behavior comprises a crystalline organic polymer, carbon black, and a high resistivity particulate filler. The high resistivity filler is semiconductive and has a resistivity at least 100 times that of the carbon black. Compositions of the invention exhibit good resistance stability when exposed to thermal cycling. They are useful in electrical devices requiring compositions with high resistivity.

Abstract: Curable compositions which are useful for encapsulating electrical connections and for joining metals to metals, and which comprise a mixture of high and low molecular weight fluorocarbon elastomers. Preferred compositions comprise a mixture of three fluorocarbon elastomers, the first having a Mooney viscosity at 121.degree. C. of at least 120, the second a Mooney viscosity at 121.degree. C. of 80 to 110, and the third a Brookfield viscosity at 100.degree. C. of 1,000 to 4,000 centipoises, in amounts 5 to 50%, 25 to 70% and 5 to 50% respectively, based on the weight of the polymeric component. The compositions can be easily molded under heat and pressure, and after they have been cured, they have remarkable resistance to degradation by hot liquids, even under pressure. Consequently, the compositions are very useful in the manufacture of self-regulating heaters for use in heating the production tubes of oil wells.

Abstract: A process for preparing an electrical device which comprises a conductive polymer exhibiting PTC behavior. The device is irradiated by use of an electron beam at an average dose rate of less than 3.0 Mrad/minute. The cross-linking may be to a level of 50 to 100 Mrad or higher for devices designed to withstand high voltage test conditions. The device may be a laminar device comprising a center layer of higher resistivity than two surrounding layers.

Abstract: A parallel circuit heating tape (13) of the kind comprising two electrical power conductors (12,15) with low resistance relatively thin heating elements (16) between them which dissipate heat, the tape (13) comprising a temperature monitoring conductor (18,25) which extends alongside one of the power conductors (12,15), the temperature monitoring conductor (18,25) being separated from the one power conductor (18,25) by a substance (23,28) which insulates the two conductors (12,18; 15,25) from one another when the temperature is below a specified temperature or temperature within a transition temperature range, and provides a current path from one conductor (12,14) to the other (18,25) when the temperature is above the specified temperature or temperature within the transition temperature range.

Abstract: An active member can deform in accordance with its temperature. The active member is connected to a mechanically-operated valve member so that the operated member is driven in accordance with deformation of the active member. The temperature of the active member is adjusted to control the operated member.

Abstract: A self-regulating heat producing strip is disposed along each wall of a room. The strip includes at least one pair of spaced apart electrical conductors extending longitudinally along the base of at least one wall and spaced therefrom. Self-limiting conductive material is in physical contact with and forms a heat generating zone between the conductors. An electrically insulated jacket longitudinally covers the conductors and the self-limiting conductive material. Connectors are provided for connecting the conductors to a power source to generate heat in the heat generating zone between the conductors.

Abstract: A cover for an automotive vapor canister has a heat-spreading member heated by a self-regulating electrical resistance heater of positive temperature coefficient of resistivity for heating air which is periodically introduced into the canister for purging the canister. The cover has a first cover of thermally insulating material defining a thin inner air flow path section to pass air being introduced into the canister over the heat-spreading member for transferring heat to the air and to receive additional heat within the first cover and has a second cover of thermally insulating material defining a thin outer air flow path section overlying and connected with the inner air flow path section to pass the air over the first cover prior to being advanced into the inner flow path section for withdrawing said additional heat from the first cover to preheat the air and improve air heating efficiency.

Abstract: An electrically energized vaporizing unit for medications, room deodorizers, room scenting compounds, room insecticides, and the like, which is simple and inexpensive in its construction and which is compact in size. The vaporizing unit includes a housing having a central slot for holding a compressed paper fiber pad which is impregnated with the substance to be vaporized. The pad is heated by a pair of electrical heating elements which are located in the housing and positioned on opposite sides of the slot for maximum vaporizing efficiency of the pad. The housing may also contain paraffin wax. The melting point of the wax is selected to correspond to the vaporizing temperature of the particular substance in the pad. The vaporizing unit is provided with an electric plug which may be directly plugged into an electric receptacle to energize the PTC heating elements, and it does not require a switch or protective thermostat.

Abstract: A self-regulating heating element having a resistor with a positive temperature coefficient as a heat source, the resistor(s) being located within a thermoplastic casing between metal parts which it (they) contact(s) in a heat-exchanging manner. For safety the element is provided with a double insulation: one part which is manufactured by moulding and which is, secondly, provided internally and/or externally with a layer of an elastomer by means of a solution.

Abstract: A method of assembling a cylindrical heater whereby the cylindrical heater includes a positive temperature coefficient thermistor element sandwiched between a pair of terminal members at its opposite electrode surfaces. The thermistor element is inserted into an opening formed in a cylindrical case of a material having heat-shrinkability and thereafter, the cylindrical case is caused to shrink by heating for holding the positive temperature coefficient thermistor element and the terminal members under pressure so as to obtain thermal connection thereof.

Abstract: Apparatus for automatically disconnecting a conductive polymer heater if an arcing fault occurs. A sensor conductor is incorporated into the heater, so that if an arcing fault occurs, the current through the sensor conductor increases and triggers a safety circuit to disconnect the heater. The sensor conductor is preferably insulated by an organic polymer which pyrolyses if an arcing fault occurs and thus permits current to flow between the sensor conductor and an electrode of the heater.

Abstract: A self-regulating warmer device which is especially suited for the food service industry. Such devices are suitable, for example, for keeping wrapped or unwrapped food products at a desired holding temperature between the time the food is prepared and the time it is delivered to the customer. The warmer device includes a plate on which the food is held and a self-regulating warmer element beneath the plate to keep the plate at a uniform temperature. The plate is preferably used with spaced apart infra-red convection heaters such as those commonly used in fast food restaurants, and provides even food heating regardless of the changes in ambient conditions, the number of food products located between the infrared heater and the plate and provides dramatic reductions in power usage. Moreover, heat losses which occur at the edges of the plates now used for these applications are reduced and localized hot or cold spots are eliminated.

Abstract: A temperature control system is disclosed for controlling heating current to a heater having an impedance which varies substantially with temperature. The change in impedance of the heater changes the degree of mismatch between the power transmission system and the heater resulting in a change in the voltage which is reflected back to the power transmission system. The reflected voltage is monitored and its magnitude compared to a reference source and the power to the heater is controlled in response to this comparison.

Abstract: A cover for an automotive vapor canister has a heat-spreading member heated by a self-regulating electrical resistance heater of positive temperature coefficient of resistivity for heating air which is periodically introduced into the canister for purging the canister. The cover has a first cover means of thermally insulating material defining a thin inner air flow path section to pass air being introduced into the canister over the heat-spreading member for transferring heat to the air and to receive additional heat within the first cover means and has a second cover means of thermally insulating material defining a thin outer air flow path section overlying and connected with the inner air flow path section to pass the air over the first cover means prior to being advanced into the inner flow path section for withdrawing said additional heat from the first cover means to preheat the air and improve air heating efficiency.

Abstract: A self-limiting electro-thermal actuator, capable of improved response time and continuous energization operation to produce a mechanical output uses plural heaters, e.g. a resistance heater and a positive temperature coefficient (PTC) heater, connected in series electrically. The actuator includes a boiler chamber, a thermally expansible working medium in the boiler chamber, a movable member responsive to expansion of the working medium to provide a mechanical output from the actuator, and a heater assembly for heating the working medium. The heater assembly includes the series-connected resistance electrical heater and PTC material heater. The electrical resistance of the PTC material increases with increasing temperature to limit current flow to the resistance heater. The heater arrangement produces improved response time over use of a PTC heater alone permitting actuators to be employed in applications for which known actuators are too slow.

Abstract: An insecticide dispenser capable of initiating the volatilization of a charge of insecticide to fumigate a room and then automatically shutting itself off during, or at the completion of the dispensing of the insecticide, whereby the dispenser can be safely left unattended during the fumigation of a room. The dispenser includes a container for the insecticide disposed upon a PTC heater, the elements being arranged adjacent a bimetal switching device that opens upon sensing a predetermined temperature, and can hold itself in the open position until intentionally reset. When the electrical circuit is open, the power supply to the PTC heater is broken and the heating will be discontinued.

Abstract: A fiber glass bushing having a thermocouple embedded in the bottom thereof and a method of preparing the same is described. The thermocouple is carried in a plate member which is welded to the bushing bottom by a weld on the outside of the busing.

Abstract: An apparatus for more accurately measuring the temperature of a fiber glass forming bushing is described which includes the placing of sidewall and bottom thermocouples in locations on the bushing so that electrical signals representing noise are eliminated or reduced significantly.

Abstract: A wall, floor or ceiling heater comprises a plurality of self regulating, preferably PTC conductive polymer, heater elements each of which is connected to two or more connection elements. The elements are held by a support. In a preferred embodiment the heater elements are positioned parallel to each other, and perpendicular to the connection elements. The support is preferably made from a rigid material which is hinged to allow the heater to be folded or rolled for easy transport.

Abstract: An insecticide dispenser capable of initiating the volatilization of a charge of insecticide to fumigate a room. The dispenser includes a container for the insecticide that is disposed upon a PTC heater. One side of the power supply necessary to initiate the chemical reaction passes directly through the cannister to the PTC heater. The other side of the power supply is connected through a support upon which the PTC heater rests. In the preferred embodiment, an electrical cut-off device is included in the circuit which will turn off the power when a predetermined temperature is attained which will be indicative of the initiation of the self-sustaining chemical reaction that causes the dispensing of the insecticide into the room.

Abstract: A pre-heater for internal combustion engines, especially adapted for use in cold climates while a vehicle is being stored, parked, or otherwise idle. The heater has a base member that is adapted to be secured in an opening of the engine block, and an electric heating element carried by the base member and exposed to the interior area of the block so as to be in contact with the coolant thereof. Electric terminals carried by the base member are connected to the heating element to effect energization thereof. An electric cable is also provided, having a plug detachable from the base member. The plug has mating terminals cooperable with the electric terminals of the base member to establish an electrical circuit through the heating element. A heat-responsive sensor device is carried by the plug, and monitors the temperature of the base member and heating element in order to effect an automatic control of the energization of the latter.

Abstract: A self-limiting electrical heater comprising an elongate resistance heating element and a PTC resistor. The resistor is elongate and extends side-by-side with and along the length of the heating element so as to be responsive to the temperature of the entire length of the heating element. The heating element and resistor are connected in series, the resistor having a positive temperature coefficient such that its electrical resistance is substantially less than that of the heating element when at a normal operating temperature but increases rapidly when exposed to temperatures above the normal operating temperature.

Abstract: The display glass of an indicating instrument which is placed in front of a displaying front plate is heated by the absorption of radiating heat which is emitted by the heating of the displaying front plate by PTC electrical resistance elements which are advantageously fastened at the displaying front plate's rear side. By way of this device that is simple and cost-effective in regard to construction, fogging is removed on a display glass of an indicating instrument and a repeated fogging is reliably avoided.

Abstract: Contact lens disinfecting apparatus is provided having first and second lens-holding chambers, an electrically conductive heat sink thermally coupled to said chambers, electrically energizable heater thermally and electrically coupled to the heat sink, a thermostat, a second heat sink coupled to the thermostat and a thermally and electrically conductive heat transfer member connected between the heater and the second heat sink.

Abstract: A brazing apparatus and process which utilizes a dual function heating and eddy current probe coil is disclosed herein. The apparatus generally includes a radiant heater assembly having a coil which is capable of both generating radiant heat to effect a braze joint between a reinforcing sleeve and a surrounding tube, as well as serving as an eddy current probe which locates the sections of this sleeve to which the brazing heat should be applied to effect the desired joint. A switching means selectively connects the coil to either a relatively high, heat-generating current, or to the aforementioned alternating current which induces eddy currents within the metal forming the reinforcing sleeve. The apparatus further includes eddy current detection circuitry for monitoring changes in the coil impedance which result from these eddy currents while the coil is slid along the longitudinal axis X of the reinforcing sleeve.