Abstract: A reflow soldering method and the apparatus thereof is described for soldering a base board having electronic elements located thereon by an inert gas circulated through heater means in a plurality of chambers while the base board is transported through all the chambers, the inert gas being circulated by ventilating means driven by drive means, the method and the apparatus thereof comprising a shield case for enclosing at least the chambers, the ventilating means and the drive means to shut off the same from an outer air and refrigerating means for cooling down the inert gas in the shield case.

Abstract: Disclosed is a method and apparatus of molding laminated plates each comprising a honeycomb core sandwiched between two opposite reinforced resin sheets as skin layers. A molding surface is composed of a plurality of unit area of divisional sections, each having a heating layer embedded therein. A prepreg is used as the reinforced resin layers. The laminated plates are formed by putting the prepreg on a honeycomb material or a honeycomb material on a prepeg, and heating the laminate by a heating layer having nichrome wires. The same procedure is repeated to cover the other side of the honeycomb structure by another reinforced resin layer.

Abstract: An improved single heating element for a furnace, and method of designing the circuit is provided.In the method of design and constructing the heating element, the voltage level of the furnace is determined, the operating temperature of the furnace is determined and then the watt level output is selected. A resistance wire is selected and the watt-density of the wire is calculated as if it were to be connected in a single strand in series. If the calculation yields a value greater than the maximum safe watt density, the watt-density is recalculated as if the wire were connected as two wires in parallel, and this calculation is repeated with an additional wire in parallel as many times as necessary to provide a watt-density less than the maximum safe watt density and constructing a furnace heating element with said finally determined number of wires in parallel.

Abstract: A flexible electric heating pad has a plurality of positive temperature coefficient (PTC) ceramic thermistor chip heating elements arranged in a two dimensional array between first and second flexible planar sheets of electrically conductive material, preferably woven of copper wire or other electrically conductive fibers. The PTC thermistor chips are disposed in spaced openings in a flexible dielectric separator disposed between the sheets and each chip has opposed planar surfaces soldered, welded or brazed to the sheets to establish electrical and thermal contact therewith. An outer flexible dielectric material covers the external surfaces of the sheets to prevent grounding or shock. A metallic enclosure, for example of stainless steel, can be formed over the outer dielectric material to add corrosion or abrasion resistance to the flexible heating pad.

Abstract: The invention is for a flat electrical heating resistance element, so called foil elements. Elements according to the invention can be used for many purposes, however, it is specially intended for use as heating elements for water beds. The object of the invention is to minimize the electromagnetic fields caused by the elements. The influence of such magnetic fields on humans is on the whole unknown why there is a common desire that the strength of these magnetic fields shall be as low as possible in order to minimize effects, if any. Heating elements according to the invention have electrical resistance wire or band placed in loops on a plastic foil surface, whereby the loops have four with each other parallel conductors, electrically connected so that in any given moment the direction of the current in the two outer conductors are in the same direction and in the two inner conductors in the same direction opposite to the outer conductors.

Abstract: An optical element whose focal length is variable comprises a medium whose refractive index is variable by temperature, a heating device for imparting heat to the medium to cause an index gradient resulting from a temperature distribution to be created in the medium, and a device for controlling the amount of heat imparted to the medium by the heating device to vary the shape of the index gradient formed in the medium.

Abstract: An electric resistance heating element for heating fluids includes a plurality of ring-shaped members made of a ceramic material having a positive temperature coefficient (PTC) disposed in concentric generally coplanar relationship, one around the other, and spaced apart from each other to form through passages for fluid flow therebetween. Electrode layers are formed at the two opposite ends of each ring and a pair of electrically conductive securing ring members are each securely soldered to a respective one of the electrode layers. Each securing ring member is integrally formed with two diametrical cross members soldered to each ceramic ring-shaped members and with each cross member having spaced grooves radially engaging and positioning the ring-shaped ceramic members. The outer periphery of each securing ring member incorporates a plurality of radially extending lugs for mounting the heating element for use and for making electrical connection between the securing ring member and a power supply.

Abstract: An electric heating unit for heating fluid, such as air in a hair drier, includes two ring-shaped electrodes and a plurality of spaced, plate-like ceramic heating elements having a positive temperature coefficient of resistance (PTC) aligned between the electrodes. The electrodes comprise an inner ring and an outer ring disposed in a nested, concentric, spaced relationship. The PTC ceramic plates are radially arranged in aligned spaced relationship with the opposite ends of each PTC ceramic plate mechanically and electrically connected respectively to the inner and outer rings. The inner and outer rings can be formed as arc-shaped segments separated by gaps prevent damage to the PTC ceramic plates by heat strain, and are provided with slits, grooves, etc., for firmly positioning the PTC ceramic plates.

Abstract: In the assembly two or more strips of resistance material are positioned edge-to-edge and fan-folded between the side members of a frame. The strips are supported at their loops by insulated fixtures and each has a terminal at each end. The strips are embossed or indented between loops so as to form longitudinally extending offsets spaced from each other across the strip. The depth of those offsets is controlled so that the clear space between the adjoining flights is just sufficient to admit a flat metal strip inserted between them crosswise with a portion projecting to form a tap. That tap can be positioned anywhere between parallel flights of the resistor ribbon after the assembly of the unit. A channel-shaped clip fits over the projecting tap and the edges of the adjoining flights of resistor ribbon and is welded to the tap and the flights.

Abstract: Industrial electric ovens and fryers of the type used for cooking precooked foods such as meats prior to packaging of the food draw high currents which tend to melt internal electrical connections. An industrial heating device includes compression-type electrical connections which reliably carry high currents and are capable of withstanding high voltage levels without breaking down. Compression-type electrical connections are used instead of the screw-type connections of the prior art to insure that all electrical connections have reliable, relatively large current-carrying cross-sectional contact areas. The electrical connection matrix of the resulting industrial heating device has increased current-carrying capacity and is much more reliable and resistant to electrical failure.

Abstract: A PTC heater for heating a tubular member includes an elongated profiled carrier body of heat conductive material having a first side provided with a flat support surface having a groove substantially perpendicular thereto extending along opposite longitudinal edges thereof and a second side provided with a channel of semi-circular cross-section for engaging the tubular member. A PTC heater element comprising a plurality of PTC resistance elements disposed between a pair of plate electrodes is positioned on the flat support surface in heat transmitting contact therewith and is covered by an elongate heat conductive cover member in flat surface engagement with the other side of the PTC heater element and provided with longitudinal rim portions closely fitted into the grooves. A U-shaped straddle clamping bracket having legs snap-fittingly anchored to the carrier body presses the cover toward the PTC heater element and carrier body.

Abstract: Elongate electrical devices, comprising two conductors with electrical elements connected in parallel between them, have improved performance if the power supply is connected to one conductor at the near end and to the other conductor at the far end. Particularly useful devices are heaters, e.g. PTC conductive polymer heaters. The power supply is connected to the far end of the device through a connection means whose electrical properties can be correlated with those of the device in order to obtain a wide range of useful results. For example the connection means can have PTC, NTC or ZTC character and can be a simple conductor or another elongate device. The power supply can be DC or single-phase, two-phase or three-phase AC.

Abstract: An electrical heating element module particularly useful for heating the teeth of a hair comb or pick includes a pair of parallel, side-by-side spaced elongated central conductors having wound thereon a fibrous inorganic electrical insulation material, such as glass yarn, with the opposite ends of each central conductor exposed. An electrical resistance heater wire is wound over the glass insulation yarn on one central conductor and then over the yarn of the other central conductor and making contact with a corresponding end of each central conductor thereby providing effectively one electrical resistance heater. The central conductors are vertically supported by a flat insulator having a pair of sockets provided with spring contacts for establishing electrical connection to the remaining exposed ends of the central conductors.

Abstract: A system, utilizing an analog pulsed signal, is for monitoring the condition of a system, by way of illustration, a multi-circuit electrically heat-traced substrate. The system senses the temperature of the substrate at the end of a heat traced circuit, converts the temperature to a pulsed signal, and drives the pulsed signal along the heat tracing to the control and distribution panel for the heat tracing in direct opposition to the AC which powers the heat tracing. A receiver converts the pulsed signal to a digital temperature read-out. Utilization of an analog pulsed signal enables the system to be used in a multi-circuit system without interference or signal mixing from adjacent circuits.

Abstract: A mineral-insulated parallel type heating cable has at least two copper or other high conductivity busbars and a plurality of separate heating elements each confined to a zone of the cable that is short compared with its total length (e.g. around 21/2 to 5 ft). Each of the heating elements is made up of a plurality of sections of metallic high resistance material which extend longitudinally (physically parallel) and connected electrically in series, while the element as a whole is connected across the two busbars. The preform for making the cable is preferably assembled by a technique using insulating material in preformed blocks.

Abstract: A self-regulating temperature controlled glow plug has a hollow metal holder, a rod-like ceramic heater and a power control heater. The ceramic heater extends from one end of the holder and has embedded therein a first resistor of tungsten alloyed with rhenium or molybdenum. The power control heater includes a second resistor embedded in a dense mass of powdered insulation material filling a tubular metallic sheath. The sheath is positioned in the holder with its central portion held in spaced relationship thereto by a thermally insulating spacer at least one end thereof. The second resistor is made of tungsten, iron or nickel, has a positive temperature coefficient of resistance at least equal to and a heating capacity greater than the first resistor, and is connected in series with the first resistor.

Abstract: A electric runner distributor heater for use in passageway of a mold into which a flow stream of fluid plastic material is introduced and which in turn communicates with a plurality of sprue orifices. The heater includes a metal casing having an exposed surface over which the fluid material is directed at an elevated temperature, a plurality of unsheathed electrical heating elements disposed in respective zones of the casing corresponding to the location of selected of the sprue orifices, heat transmitting material compacted in the bore of the casing and surrounding each heating element for electrically insulating the heating element from the casing and filling all air voids between the casing and heating element to effect direct heat transfer to the casing from the heating element, leads coupling the heating elements to a power source, and a control for independently controlling the temperature of the heating elements and thus the temperature of respective zones of the casing.

Abstract: An electrically heatable hair wrapper capable of being cut to any predetermined length from a flat, elongated, flexible base carrying a plurality of parallel resistance heating circuits. The circuits extend along the length of the base in a periodic serpentine pattern with the opposite ends of each pattern being electrically connected to continuous parallel buses extending along the longitudinal edges of the base. The flexible base is provided with indicia for indicating where the base and buses may be cut intermediate each adjacent pair of serpentine patterns so as not to destroy the continuity of the selected resistance heating circuits. A bendable, shape-retaining, cuttable wire along each longitudinal edge of the base outwardly of the parallel buses holds the wrapper in any desired shape. A longitudinally flexible flap integrally formed with at least one longitudinal edge of the base is foldable over the base to retain a hair tress between the base and flap during use of the wrapper.

Abstract: A fuel heater for vaporization of an alcohol fuel from a fuel line to an internal combustion engine for delivering vaporous fuel to a carburetor. The fuel heater includes a stack of generally planar foraminous PTC heaters that are arranged in a container having an insulated interior defining a fuel flow path having an inlet and an outlet and are separated from each other by generally flat ring-like conductive spacers with electrically conductive ears having conductor receiving holes therein. Alternate conductive spacers are disposed in two channels in a housing and connected to opposite sides of a power supply whereby said PTC heaters can raise the temperature of the incoming fuel and vaporize it. Alternative ears of the electrically conductive spacers are radially offset from each other whereby one row of ears is disposed in one channel and another row is disposed in the other channel.

Abstract: A rigid frame supported resistor for dynamic braking of electric and diesel-electric locomotives has certain of the frame elements cushioned or insulated from each other and the resistance ribbon insulated and cushioned from the frame. Organic insulating material in molded or sheet form, preferably a copolymer, such as a polyester resin, protected by a metal heat shield, may be used for structural frame members, or for cushioning and insulating metal structural frame members. The organic insulating resistant is supplemented by ceramic insulating material in locations subject to high heat.

Abstract: A self-regulating electric heater includes a plurality of ceramic PTC resistors having flat contact surfaces on their opposite sides disposed between a pair of flat electrode plates with the contact surfaces in electrical and thermal contact with the plates. A support frame of electrically insulative material is formed with receiving portions respectively for the PTC resistors and the electrode plates to positions and hold the resistors and plates in assembled relationship for insertion as a single assembly into a closed-end cavity in a metallic radiator with the electrode plates in good heat transfer contact with the inner wall surface of the cavity. The frame is provided with spring seats receiving springs which coact with the radiator to bias the support frame into the cavity to insure stable intimate thermal contact between the electrode plates and inner cavity wall. The PTC resistors may be provided with chamfered edges along the peripheries of the flat contact surfaces thereof.

Abstract: Elongate electrical devices, comprising two conductors with electrical elements connected in parallel between them, have improved performance if the power supply is connected to one conductor at the near end and to the other conductor at the far end. Particularly useful devices are heaters, e.g. PTC conductive polymer heaters. The power supply is connected to the far end of the device through a connection means whose electrical properties can be correlated with those of the device in order to obtain a wide range of useful results. For example the connection means can have PTC, NTC or ZTC character and can be a simple conductor or another elongate device. The power supply can be DC or single-phase, two-phase or three-phase AC.

Abstract: An exhaust particle cleaning device for a diesel engine includes a trap case provided in a passage way of exhaust gas. A filter material is disposed in the trap case so that carbon particles or other exhaust particles contained in the exhaust gas can be caught within the filter material during the time the exhaust gas is passed through the filter material. A plurality of electric heater elements are spread or dispersed on the upstream end face of the filter material, so that the exhaust gas passes through the areas defined between the plurality of heater elements. The electric heater element may be coated with a ceramic material.

Abstract: A heating cable for use with an electric underblanket the cable being of the type in which a sensor wire is employed coextensive with a heater wire and separated by a layer of meltable insulating material so that overheat conditions are sensed by contact between the sensor wire and the heater. A number of helically wound coextensive wires cooperate with switching means to provide overheat temperature sensing at various wattage levels of heating.

Abstract: A heating resistor of a single crystal manufacturing apparatus, which comprises a cylindrical side wall portion surrounding a melting pot, a bottom portion supporting the side wall portion, and a plurality of slits formed in the side wall portion and bottom portion, wherein said bottom portion has a maximum thickness which is not greater than that of said side wall portion, and said bottom portion has a minimum inner diameter which falls within a range of 20 to 80% of an inner diameter of a lowermost portion of said side wall portion.

Abstract: A thermal head is provided with first and second sets of parallel bar-shaped electrodes which are arranged in slightly spaced parallel planes and cross over one another. Individual crossing resistors are selectively energized to produce a heat generating dot which may be reproduced on a heat sensitive media.

Abstract: A heater which includes: at least two electrically conductive heating element units having generally a self-standing cylindrical shape and stacked one on another to define a series of at least two cylindrical heating zones, the heating element units each including of a grid-like structure alternately having a vertically disposed portion and a horizontally extending bridge portion; insulator blocks fitted on the ends of stacked upper and lower cylindrical heating element units which meet and which are made of a material having a sufficient electric resistance that will not conduct electric current at a maximum operating temperature of the heating element units; and an annular shaped connector conforming with the ends of the upper and lower heating element units which meet and which is interposed between the insulating blocks on the ends which meet to provide a mechanical connection between the stacked upper and lower heating element units.

Abstract: A self regulating heater for use in an early fuel evaporation (EFE) system for an automotive engine includes a thermally conductive thick metal radiator body having a heat receiving side an opposite side provided with a plurality of heat-disturbing fins for transferring heat to a fuel heating zone. A plurality of self-regulating ceramic electrical resistance having a positive temperature coefficient of resistivity (PTC) each have a first side bonded by an electrically and thermally conductive adhesive to a first side of a thin thermally and electrically conductive metal plate. The plate has a limited portion thereof secured, for example, by a screw, in electrically conductive relation to the radiator body with the opposite side of the thin plate in closely spaced, facing, heat-transfer relation to the heat receiving side of the radiator body.

Abstract: A self-regulating heater for use in an early fuel evaporation system for an automotive engine includes a metallic radiator having a first heat-receiving side and an opposite side for transferring heat to a fuel evaporization zone. Self-regulating ceramic electrical resistance heater elements having a positive temperature coefficient of resistivity(PTC) are disposed with first sides in facing relation with respective recessed first portions of the heat-receiving side of the radiator. A thermally conducting metal heat-transfer member has recessed first portions disposed in facing relation to respective second sides of the heater elements to receive heat second sides of the heater elements to receive heat from the second sides of the heaters and also has second portions disposed in closely-spaced facing relation to corresponding second portions of the heat-receiving side of the radiator, thereby to transfer the heat received from the second heater sides to the radiator.

Abstract: A flexible barium titanate ceramic PTC heater for use in, for example, an intake pipe of an internal combustion engine to heat the air-fuel gas mixture is formed as a thin disc-shaped ceramic sheet constituted by a plurality of individual coplanar ceramic segments having interior edges positioned in spaced side-by-side relationship. The juxtaposed edges of the ceramic segments are united to each other by a flexible, heat-resistant, electrically non-conductive rubber band disposed in the space between the segments and bonded thereto by an electrically non-conductive adhesive to form the segments into a thin disc-shaped sheet which can be flexed without causing flexing of any of the individual segments. The ceramic heater is positioned in a metallic casing with one planar face thereof bonded to the inner surface of the casing by an electrically conductive adhesive. A stainless steel wool cushioning member engages the other planar face of the ceramic heater to support the heater in the metallic casing.

Abstract: An electrical resistance heating element comprises at least one heating conductor of positive-temperature-coefficient material having contact means on opposite surfaces; if more than one, they may be arranged in a row or in a stack. Electrical connection is made to the heating conductor or the row or stack through two substantially plane contact plates adapted to the layout of the heating conductor, row or stack and placed loosely upon opposite contact surfaces thereof. The components are held together elastically by securing means holding the edges of the contact plates. Two alternative forms of securing means are described, one consisting of a series of U-shaped clips of elastic material distributed along the edges of the element, the other consisting of strips of U-shaped cross-section which are made of material with soft elastic properties and extend along respective opposite edges of the heating element.

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

Abstract: A heating element comprising a plurality of ceramic components strung together on a heating wire to form a flexible structure, adjacent ceramic components comprising integrally formed mating projections and depressions.

Abstract: A heated hair straightener has a handle connecting to an electric source and a pair of scissor-like clamp housings pivoted on the handle and having facing coverplate surfaces for clamping and straightening the hair. This combination has an improvement in the heater sub-assembly fitting in one of the housings and formed as a sandwich arrangement including an aluminum coverplate, a copper elongated heater plate forming a first electrode connected to one side of the line and electrically insulated from the coverplate by a thin dielectric film. Plural PTC heater pellets are aligned on the heater plate and held by an insulating locator panel having cut-outs fixing the pellets on the heater plate. A second electrode, formed as a corrugated stainless steel spring plate covers and abuts the PTC pellets and is connected to the other side of the line. Next is a phenolic or ceramic insulator member with a recess for the corrugated spring plate to fit and abut therein.

Abstract: Air is pumped from an upper chamber in a cylindrical housing through parallel groups of Ni-Cr steel heating tubes to a lower chamber communicating with a carbon-dioxide adsorber in an air-rectification system. The tube groups are suspended at their upper ends from respective Al.sub.2 O.sub.3 -ceramic holder plates seated on flanges projecting into respective openings of a carrier plate in turn removably fastened to the inside of the housing. The tubes in each group are connected in series with one another to a voltage source, the lower ends of the tubes in a group being gripped by a form-fitted ceramic spacer slidably inserted into a pipe section aligned in a support plate with an associated opening in the upper carrier plate, thereby ensuring the electrical insulation of the tubes. The holder plates and the openings are shaped as circles or as circular sections.

Abstract: A heater plate for plunger-type molding presses comprises a plurality of electrically heated heating elements which are inserted into holes through the plate. These holes are disposed in rows parallel to the peripheral outline of the plate so that the density of the heating elements decreases toward the center of the plate. The heating elements are interconnected and also connected to a temperature control device so that the heating elements can be selectively heated whereby the plate can be uniformly heated in spite of higher heat loss at marginal portions of the plate.

Abstract: A self-regulating heating element comprising a tubular body closed at each end and containing two longitudinal electrically and thermally conductive flat strips arranged parallel to and spaced from each other. Each flat strip is provided along at least one longitudinal edge thereof with an abutting longitudinal resilient heat-conductive strip conforming with the adjacent surface of the inner wall of the tubular body so as to be in resilient heat-exchange contact with such inner surface for conducting heat from the flat strip to the tubular body. At least one PTC resistor is positioned between and in electrical and heat-exchange contact with the parallel flat strips, electrical terminals extending through the tubular body into contact with the flat strips. Such heating elements find particular use as immersion heaters for liquids and as the heat source in hair-curling devices.

Abstract: A positive temperature coefficient (PTC) resistance heater assembly is used in combination with an angle of attack vane to provide automatic means for maintaining the temperature of the vane at a level which will de-ice the vane. The heater assembly is embedded in a recess in the vane and is made up of a plurality of individual PTC resistors connected electrically and mechanically in parallel by flexible electrically conductive perforated strips which permit the individual resistors to move relative to each the other under thermal stress and which also permit the encapsulation of the resistors in a suitable thermally conductive, electrically oinsulative material that is sufficiently resilient to permit the individual resistors to expand and contract relative to the vane during use.

Abstract: A heat-emitting radiator supplied with electrical energy and preferably capable of co-acting with two holding means in conjunction with a radiator-supporting means, such as a wall. The holding means associated with the radiator comprise a first rail preferably having current-conducting means, and a second rail. One or more cassettes being insertable between the rails. A connecting cassette without heat-emitting resistance device has a contact means for co-operating with the contact rail. Said connecting cassette is inserted in the first rail and the second rail, arranged to feed current to said contact rail. Each further cassette is held in the rails, feed by current applied to said contact rail.

Abstract: A heat-emitting radiator supplied with electrical energy and preferably capable of co-acting with two holding means in conjunction with a radiator-supporting means, such as a wall. The holding means associated with the radiator comprise a first rail preferably having current-conducting means, and a second rail. One or more cassettes being insertable between the rails. Each cassette has a contact means for cooperating with the contact rail. Each cassette is further arranged to be inserted in the first rail and the second rail in a first position of rotation. The cassette is arranged to be held in the rails in a second position of rotation.

Abstract: An improved tubular oven adapted for use in diffusion processing of semiconductors whose interior walls are comprised of polycrystalline silicon and whose exterior walls are comprised of phosphorous doped silicon. Block electrical contacts are located at opposed ends of such tubular oven and are comprised of conductive metal and graphite. A layer of thermal insulation circumscribes mid regions of such tubular oven.

Abstract: A radiant heating modular array of rapid response radiant heating units includes a plurality of abutting heating element frame units in which the intermediate frame units have open sides and the end frame units have closed outer sides. Means on the front and back walls of the frame units support a plurality of thin foil radiant heating elements. Means including connectors of equal length interconnect the heating elements within each frame unit and from each of the abutting frame units to its contiguous unit whereby all of the heating elements are equally spaced laterally of the entire module to provide uniform heating and to avoid heat striation at the juncture of the units. The radiant heating module is controlled by electronic feedback circuitry including optical temperature sensors whereby the applied heat can be profiled to compensate for processing irregularities.