Abstract: In order to increase the stability of a device comprising at least one electrode and a conductive polymer composition in contact therewith, the contact resistance between the electrode and the composition should be reduced. This can be achieved by contacting the molten polymer composition with the electrode while the electrode is at a temperature above the melting point of the composition. Preferably, the polymer composition is melt-extruded over the electrode or electrodes, as for example when extruding the composition over a pair of pre-heated wires.

Abstract: In order to increase the stability of a device comprising at least one electrode and a conductive polymer composition in contact therewith, the contact resistance between the electrode and the composition should be reduced. This can be achieved by contacting the molten polymer composition with the electrode while the electrode is at a temperature above the melting point of the composition. Preferably, the polymer composition is melt-extruded over the electrode or electrodes, as for example when extruding the composition over a pair of pre-heated stranded wires.

Abstract: An electrical heating cable comprises two or more electrical conductors provided individually or collectively with a covering of electrical insulation material. The cable includes a heating element comprising a heating wire wrapped in a helical configuration about a core formed of a bundle of glass fibre filaments. The heating element is joined to alternate conductors by soldering or welding at intervals along the length of the cable. The element is mechanically independent of the conductors between the junction regions, the conductors and the element being held together by an outer sheath.

Abstract: The flat electrical resistance heating element is intended principally for a household article having a heating surface.The heating element comprises a heating resistance cut out from a metal sheet (1) which is coated with a substrate (2) of electrically insulating material resistant to the heating temperature and adherent to the metal sheet (1) and to the material of which the support (5) of the heating surface of the article is made.Use principally in base-heated kitchen utensils and irons.

Abstract: Diesel fuel is heated prior to filtration by passing it in thermal contact with a laminar heater immersed in the fuel. The heater has a resistance at room temperature of 0.30 to 0.75 ohm and comprises a PTC conductive polymer resistive heating element sandwiched between equispaced imperforate metal foil electrodes, particularly electrodeposited foil electrodes, coextensive with resistive heating element. The conductive polymer has a resistivity at room temperature of 20 to 2000 ohm - cm. The resistive element has a cross-sectional area in a plane parallel to the electrodes of 3 to 10 square inches and the electrodes have a microrough surface in direct physical contact with the conductive polymer.

Abstract: Melt-shapeable polymeric compositions comprising a first fluoropolymer of relatively low crystallinity, e.g. a copolymer of tetrafluoroethylene and a perfluorinated comonomer, and a second fluoropolymer of relatively high crystallinity, especially a fluoropolymer obtained by irradiating PTFE or another fluoropolymer which cannot be melt-shaped in the absence of other polymers. The weight ratio of the first to the second polymer is preferably 0.3:1 to 2.5:1. The compositions have a wide variety of uses, for example as insulating materials or, if they contain carbon black or another conductive filler, as PTC conductive polymers.

Abstract: A self regulating heating device for a mirror is disclosed including a substrate having an electrical buss system deposited on one surface including a plurality of interdigitated electrodes and two buss bars. Stripes of positive temperature coefficient resistive material are printed perpendicularly over the buss system to form a plurality of heater areas and exposed substrate areas. A first adhesive layer is deposited over the resistive layer and adheres to the exposed areas of the substrate. An electrical barrier layer is secured to the first adhesive layer and a removable protective covering is secured by the second adhesive layer. The buss bars are tapered such that the power density at any point along their length is substantially equal to the average power density of the heater areas.

Abstract: An electroceramic device formed of a body of electroceramic material and a process of making the device is disclosed. The body has an outer perimeter edge and two sides, each of the sides forming an exterior face. At least one groove is disposed on one of the exterior faces of the body, the groove extending from the edge and forming an opening on the exterior face. A lead wire is disposed in the groove and extends outwardly from the body through the edge. A metallized, electrically conductive coating is disposed on each of the exterior faces, and are electrically insulated from each other. The coating fills any voids left between the lead wire and the interior of the groove, whereby to hold the lead wires in place within the groove and form an electrical connection with the coating. Another lead wire is provided for the other coating, and that lead wire may be disposed in another similar groove.

Abstract: A thermally self-regulating elastomeric composition and heating element made therefrom. The composition includes a body of elastomeric material in which is distributed electrically conductive particulate material, such as carbon black. Short fibers are also distributed in the elastomeric matrix. In the disclosed invention, the short fibers are present in the amount of approximately 0.5 to 20 volume percent. In one alternate form, the matrix is foamed. Different arrangements of the electrodes in electrical conductive association with the thermally self-regulating elastomeric body are disclosed. Preferred proportions and characteristics of the particulate conductive material and short fibers providing optimum thermally self-regulating characteristics of the composition are disclosed.

Abstract: To measure the amount of carbon dioxide in a mixture of gases, a source of infrared light includes a porous getter emitted formed of an inner tungsten heater with a layer of sintered together zirconium and carbon powder covered with spectrographic grade carbon over at least 50 percent of its surface serving as a getter and an emitter of infrared light. It is mounted within a vacuum and emits light in a strong spectrum including light having a bandwidth of at least 150 nanometers with a center point of substantially 4.2 micrometers. The light is transmitted through reference and sample flow cells each including a corresponding one of a reference gas and a sample gas onto a photosensor. The light source includes a reflector located within a range of no more than 1 centimeter from the emitter getter for reflecting heat back to said emitter getter at least 50 percent of its surface and has a window aligned with said infrared light sensor with an opening of area of between 0.05 to 20 square millimeters.

Abstract: A self-regulating PTC heater in which the direction of flow of current is reversible in a region of the PTC material in response to a change in the resistivity of the material whereby current in-rush is reduced.

Abstract: Improvements to electrical devices comprising conductive polymer compositions are described. The device, preferably a heater, comprises two electrodes, preferably planar electrodes and a conductive polymer composition, which preferably exhibits PTC behavior, and which is preferably sandwiched between the electrodes. At least one of the electrodes comprises a metal with a thin layer of high resistivity material attached thereto, e.g. anodized aluminum, so that the layer separates the electrode and the conductive polymer composition. This raises the room temperature resistance of the device and thus reduces the in-rush current.

Abstract: A flexible heating cable using positive temperature coefficient thermistors as a primary heat source with the thermistors being electrically and mechanically connected to substantially flat, preferably braided, electrical conductors with dielectric material preferably separating the conductors. A covering of dielectric material preferably is used to electrically separate the cable from the environment. The cable construction improves the heat transfer from the thermistors to the environment and improves the temperature distribution of the cable.

Abstract: A sheet electrical heating element comprising warp yarns which are constituted of a plurality of warp electrically conductive yarns disposed at predetermined intervals and a plurality of warp electrically non-conductive yarns, one or more of which are arranged in each of said intervals of the warp electrically conductive yarns; and weft yarns which are constituted of a plurality of adjacent weft electrically non-conductive yarns and a weft woven electrode of predetermined length in the warp direction. The woven electrode is constituted of weft electrically conductive yarns forming fancy twill weave together with the warp yarns so that the texture may be loose and flexible.

Abstract: Method for monitoring the electrical integrity of a heater and a novel heater for use in such a method. The heater includes an elongate heating member; an insulating jacket which encloses the heating member; a first electrically conductive member which surrounds the insulating jacket; a separating and insulating member which surrounds the first conductive member; and a second electrically conductive member which surrounds the first conductive member and is separated and insulated therefrom by the separating member. The method includes the step of testing the electrical relationship between the first and second electrically conductive members.

Abstract: A heating element made of carbon, comprising a heating member including carbon powder and an insulating resin, the powder being kneaded with the resin, and a core member formed of an insulating material and having a higher fusing point than the heating member, the core member being disposed substantially centrally of the heating member.

Abstract: A self-regulating heating article comprises a first elongate layer formed by a crystalline polymeric composition of high crystallinity and conductive particles dispersed in the polymeric composition to exhibit a positive temperature coefficient of resistance. A pair of elongate electrodes, which are adapted for connection to a mains supply, are secured one on each surface of the first layer to develop a potential in the direction of thickness of the first layer. The electrodes are arranged so that a creeping distance which is greater than the thickness of the first layer is established between the electrodes along peripheral edges thereof. The creeping distance prevents insulation breakdown and ensures safe, high wattage operation at mains voltages.

Abstract: In an electrical surface heating element, there are conductors (10) embedded within a panel (1) of electrically insulating material, which conductors are connected to supply conductors or, respectively, to the heating conductors of the surface heating element, and enter cavities (7) of the panel (1) open to the panel edge (6), within which cavities the electrical connecting points for connecting adjacent panels (1) are located. Each cavity (7) is constricted in direction towards the panel edge (6) and can be closed above by at least one removable cover (15,16), so that the connecting points of the conductors (10) are accessible also after having installed the panels (1).

Abstract: In order to increase the stability of a device comprising at least one electrode and a conductive polymer composition in contact therewith, the contact resistance between the electrode and the composition should be reduced. This can be achieved by contacting the molten polymer composition with the electrode while the electrode is at a temperature above the melting point of the composition. Preferably, the polymer composition is melt-extruded over the electrode or electrodes, as for example when extruding the composition over a pair of pre-heated stranded wires.

Abstract: An electrical heating device comprises a substrate, a pair of parallel, spaced apart elongated conductors extending longitudinally of the substrate, and a semi-conductor pattern carried on the substrate and electrically connected to and extending between the conductors. The semi-conductor pattern produces a thermal image for an infrared target. In some embodiments, the thermal image is irregular or circular in shape and the semi-conductor pattern includes a plurality of transversely-spaced bars having relatively wide portions outside, and relatively thin portions within, the area producing the thermal image.

Abstract: A perforated flat ribbon heating element embedded or sandwiched between the porous material and perforated sheet of honeycomb acoustic panel material used for sound suppression and deicing on ice buildup areas of an aircraft engine.

Abstract: This specification teaches an electrically heated, glass vision unit having a complex curved configuration. The unit is made by cutting a glass substrate (10) from a flat glass bracket (12). The glass substrate (10) has first and second surfaces separated by a uniform distance. A pair of electrically conductive bus bars (16--16) are applied to one of the surfaces of the glass substrate (10). The bus bars (16--16) are so positioned on the flat glass substrate (10) that when the substrate (10) is bent to form the glass vision unit of complex curved configuration, inboard edges (16a--16a) of the pair of electrically conductive bus bars (16--16) are equally distant from one another throughout their entire extent. The flat glass substrate (10) is bent to form the glass vision unit of complex curved configuration. A conductive coating (20) is applied to the one surface of the glass substrate (10) and extends between the pair of bus bars (16--16) throughout their entire extent.

Abstract: The resistivity/temperature characteristics of PTC conductive polymers which have little or no cross-linking can be modified by stretching. The rate at which resistivity rises with temperature is increased, and the peak resistivity is decreased; however, the decrease in peak resistivity is substantially smaller than that observed with PTC conductive polymers having a high degree of cross-linking. Therefore, heat-recoverable electrical devices, particularly for covering telephone and other cable splices, comprise (a) a layer of a PTC conductive polymer which has little or no cross-linking, (2) an adjacent heat-recoverable layer of a PTC or ZTC conductive polymer which has a relatively high level of cross-linking, and (3) electrodes which can be connected to a power supply so that current passes through the layers and causes recovery of the device; preferably an uncrosslinked PTC layer is sandwiched between two cross-linked ZTC layers. Non-recoverable devices, e.g.

Abstract: An electric resistance element (1) in a device for deicing a wing structure such as the wing of an aircraft or the blades of a helicopter, which includes conducting fibers embedded in a composite fiber structure and power supply wires connected electrically to said conducting fibers. In this element, the conducting fibers are carbon fibers in the form of at least one ribbon (2) in which the fibers are oriented longitudinally, preimpregnated with resin and at least one end of which is fixed in a deformable tubular metal mesh element (3) providing the electric connection by contact with the ribbon and which in turn is soldered to the corresponding power supply wire (4).

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: A parallel, zoned heating cable wherein parallel electrical conductors are spaced outwardly from a central heating element preferably formed of a fibrous material containing carbon or graphite or coated with a conductive polymer. Heat conducting dielectric members are preferably located between the heating element and the electrical conductors for improved thermal distribution of the cable. The conductors are alternately connected by splices to the electrical conductors to produce heat of a constant wattage.

Abstract: A heated automobile backlight having a dark colored electroconductive grid. The composition includes silver powder, a glass frit such a lead borosilicate frit, and reducing agents such as stannous sulfate and chromic oxide.

Abstract: A planar heat generator comprises a heating element of metallic foil; a first pair of sheets made of a plastic material which are bonded to each other so that the heating element is interposed therebetween; a second pair of sheets made of a plastic material which are bonded to the outer surfaces of the first pair of sheets, respectively; and a pair of protective covers which are made of a plastic material having a melting point at least approximate to that of the material of the second pair of sheets. The protective covers are larger in area than the second pair of sheets and are bonded by fusion not only to the outer surfaces of the second pair of sheets, respectively, but also to each other at peripheral areas which extend beyond the peripheral margins of the second pair of sheets.

Abstract: A panel heating element comprising (a) a metal substrate, (b) an aluminum boron-silicate insulating glass which forms a coating on the metal substrate, (c) one or more metallic resistance tracks applied to the substrate and (d) a mixture of a zirconium phosphate glass and a boron-titanium enamel which is applied as a layer over the metallic resistance tracks.

Abstract: A heating element for textiles is disclosed, which comprises a plane textile element and, combined with this, metal conductors, which can be connected to a source of electrical current and which oppose the electrical current flowing through them with a heat-producing resistance. As resistance elements, the conductors have metallic fibers or filaments with a denier like that of natural or synthetic textile fibers. The metallic fibers or filaments have an average cross sectional thickness of about 8 to about 24 microns.

Abstract: In a radiant heating unit, an insulating support for carrying a radiant heating resistor is molded or pressed using a granulation of expanded clay materials, particularly expanded mica or vermiculite. The granulation is compressed and bound in a blank by a mineral binder, particularly water glass, and the heating resistor is positively secured in the moulded granulation by embedding parts of the resistance wire forming the resistor, in such a way that the resistor is in part free of the insulating support on the front. The heating resistor can be embedded during production of the insulating support or can subsequently be pressed into the support. The insulating support of the heating unit is low in weight and easy to manufacture, has optimum electrical and thermal insulating properties and has very good strength, whereby the heating unit has a long service life.

Abstract: An electric heater is described. The heater is composed of a plastic or a rubber strip conductor with a heat resistant and electric conductive chemical dispersed therethrough and electric conductors disposed on either side of the strip conductor so that when the electric conductors are coupled to a source of electrical energy current will flow through the strip and generate heat. The strip conductor then is covered with a polyethylene layer which is adhered thereto, and the polyethylene layer in turn is covered by a PVC layer.

Abstract: A flexible thermosensitive wire used for electric heating fabrics, such as electric blankets, electric carpets etc., which wire is protected against damage from dry cleaning solvents to allow safe dry cleaning of the electric heating fabrics. The flexible thermosensitive wire includes a thermosensitive polymer composition layer formed between at least one pair of electrodes and is covered with a jacket, wherein at least part of the jacket is composed of a barrier polymer material which is resistant to dry cleaning solvents.

Abstract: A ceramic heater comprising a ceramic substrate is described which has formed thereon a layer of a silicide of an element selected from groups IVa, Va and VIa of the periodic table. The heater has stable temperature vs. resistance characteristics, has high mechanical strength and produces the desired temperature in a very short period of time.

Abstract: An improved defogging and deicing shield structure suitable for use as a face shield in combination with a protective helmet or for use in goggles having at least two spaced coextensive lenses. The inner surface of one lens is imprinted with an electrical circuit in a predetermined pattern. The resistance of the circuit being sufficient to generate heat effective to defog or deice the exterior surface of the other lens when the circuit is connected to a direct current power source.

Abstract: A heating element for bathroom and similar mirrors is formed as a laminate for placing behind a conventional mirror glass. The laminate has separate foil conductor patterns forming distribution and return conductors for the supply current, and a continuous conductor layer formed by a higher resistivity conducting paint or coating extending between the conductor patterns. Preferably the conductor patterns are formed as longitudinal bands on a continuous web of insulative substrate material which is then cut into lengths which are mounted on backing sheets of appropriate size and which carry buses to establish connection between the conductor bands and an electrical supply.

Abstract: An electrical heating element intended to be incorporated in an inner lining of an item of clothing or accessory intended to be placed against a part of the human body, in which the heating element is formed by a ductile metal wire coated with an insulating lacquer, for example a commercially available insulated copper wire, fixed over its entire length to at least one metal sheet, preferably a sheet of aluminium having an adhesive side to which the wire is adhered. The wire can be disposed in meanders. It may be covered by an insulating sheet, and the metal sheet may have cut-outs therein.

Abstract: A self-regulating heating article comprising a layer of material exhibiting a positive temperature coefficient of resistance (PTC) and said PTC layer having at least partially contiguous therewith at least one layer of constant wattage output material. The article operates such that when connected to an electric power source, the current flows through at least a portion of the thickness of the PTC layer and of the constant wattage layer.

Abstract: Circuit protection devices comprise a PTC conductive polymer element within a hollow enclosure which is sealed except for at least one vent. The vent is sealed by means of a cover member, preferably of adhesive tape. The exterior surface of the enclosure adjacent the vent and under the cover member is provided with indentations which change the internal pressure required to blow the cover member off the vent, and/or enable the cover member to open during a hot washing step and subsequently to reseal without admitting wash liquid, and/or control the direction in which gases flow after passing through the vent.

Abstract: A heat-sensitive electroresistive composite and a thermostatic heating unit made from the composite. The heat-sensitive electroresistive composites have the property of showing an abrupt variation in electric resistance depending on temperature, and they include organic compounds containing a plural number of alkylene oxides as the unit structure in their molecules and fine pieces of carbon in the form of powder, fiber, whiskers, etc. The above-mentioned organic compounds may be normal chain polyalkylene oxide and its derivatives or cyclic ether compounds. The mixing ratio of organic compounds to the fine pieces of carbon is, for example, 100 to 10-80, but the mixing ratio is not necessarily limited to the range for the other types of organic compounds and fine pieces of carbons. The thermostatic heating units are formed by sealing the heat-sensitive electroresistive composites together with electrodes within insulators.

Abstract: A planar resistance heating element with positive temperature coefficient characteristics includes a resistive body layer formed of a crystalline resin containing electrically conductive particles and disposed between at least a pair of electrodes on an insulating substrate. A phenolic resin layer or a denatured phenolic resin layer with an elastomer resin added is disposed on the resistive body layer in covering relation to the entire surface thereof. An insulating protective film of resin may be disposed on the covering layer with an adhesive layer interposed therebetween, and an adhesive layer may be disposed on an outer surface of the insulating protective film for attachment to an object to be heated.

Abstract: In a heating element comprising an electrical resistance layer disposed between two areal electrodes extending generally parallel to one another, the resistance layer is formed to be thermally insulating and is permeated with electrically conductive plastics material having a positive temperature coefficient of electrical resistance. The conductive plastics may comprise thermoplastics material incorporating a particulate filler of granular, spheroidal or bubble form, and the electrodes may be coated black to serve as black bodies. The element may be disposed within a thermally insulating member acting as a heat shield.

Abstract: A thin bed sorption/desorption apparatus includes a heater element laminated within a high temperature chemically inert polymer with an adhesive on the outside of the laminate being used to attach a thin film of small particle size sorptive material. Various embodiments of the apparatus are each arranged to provide a flow of a sample to be analyzed across the surface of the sorptive material. The method for making the thin bed sorption/desorption apparatus includes the steps of encapsulating a thin-film heater element in a laminated structure of a polyimide which is a high temperature, chemically inert polymer. The outside surface of the laminate is coated with a polyimide adhesive which is diluted with dimethyl formamide. The sorptive material in the form of a powder having a maximum particle size of 100 mesh is applied to the wet adhesive. Subsequently, the coated structure is heat cured at approximately 220.degree. C.

Abstract: Apparatus and method for heating liquids, e.g. diesel fuel, by means of a conductive polymer heater which does not have an insulating jacket, so that there is direct physical contact between the liquid and electrically conductive parts of the heater. This results in improved heat transfer to the liquid. The unjacketed heater comprises a pair of elongate spaced electrodes embedded in an elongated strip of a conductive polymer, such as cross-linked polyvinylidene fluoride, which exhibits PTC behavior. The heater is positioned in a container through which diesel fuel to be heated flows from an entry port to an exit port. The exterior surface of the polymer strip is exposed and is directly contacted by the flowing diesel fuel.

Abstract: Circuit protection devices comprise a PTC conductive polymer element and means for minimizing the adverse effects of carbonaceous dust evolved by the PTC element when it is tripped. An enclosure encloses, but is spaced apart from, the PTC element. In one embodiment at least part of the interior surface of the enclosure is composed of polytetrafluoroethylene, a ceramic or another material which discourages the formation of permanent low resistance paths through carbonaceous material lying on its surface. In another embodiment the enclosure has a large internal surface area compared to the volume of the PTC element. In further embodiments, electrical leads are connected to and pass through the enclosure, and at least one of the leads is insulated along its length and/or the leads pass through opposite ends of the enclosure.

Abstract: Circuit protection devices comprise a PTC conductive polymer element and means for minimizing the adverse effects of carbonaceous dust evolved by the PTC element when it is tripped. An enclosure encloses, but is spaced apart from, the PTC element. In one embodiment at least part of the interior surface of the enclosure is composed of polytetrafluoroethylene, a ceramic or another material which discourages the formation of permanent low resistance paths through carbonaceous material lying on its surface. In another embodiment the enclosure has a large internal surface area compared to the volume of the PTC element. In further embodiments, electrical leads are connected to and pass through the enclosure, and at least one of the leads is insulated along its length and/or the leads pass through opposite ends of the enclosure.

Abstract: Circuit protection devices comprise a PTC conductive polymer element and means for minimizing the adverse effects of carbonaceous dust evolved by the PTC element when it is tripped. An enclosure encloses, but is spaced apart from, the PTC element. In one embodiment at least part of the interior surface of the enclosure is composed of polytetrafluoroethylene, a ceramic or another material which discourages the formation of permanent low resistance paths through carbonaceous material lying on its surface. In another embodiment the enclosure has a large internal surface area compared to the volume of the PTC element. In further embodiments, electrical leads are connected to and pass through the enclosure, and at least one of the leads is insulated along its length and/or the leads pass through opposite ends of the enclosure.

Abstract: An electric heater has an elongated cylindrical quartz tube provided at each end with a terminal and a heater coil having one end connected at each terminal has a helical portion disposed within the tube and extending the length thereof. A ceramic support disposed in the tube extends the length of the helical portion of the coil and is formed with a heat-reflecting longitudinal groove having mutually inclined opposing sides which flank at least a portion of the circumference of the turns of the helical portion. Each of the opposing sides of the groove engage the turns of the helix tangentially in point contact, the support holding the helical portion with the turns thereof in tangential point contact with the inner surface of the tube. Each turn of the helical portion is supported at three separate points.

Abstract: A method for heating diesel prior to filtration by passing the diesel fuel through a heating apparatus including a container having entry and exit ports for the fuel and an elongated electrical heater arranged in spaced apart coils within the container for directing the flow of fuel so that, as the fuel flows from the entry port to the exit port, it flows along an elongate curved path which follows the coils of the heater and which curved path preferably has a length at least eight times the straightline distance between the entry and exit ports. The electric heater is unjacketed and comprises a pair of elongate electrodes embedded in an elongate strip of a conductive polymer composition which exhibits PTC behavior. The exterior surface of the elongate polymer strip is exposed so that it is directly contacted by the diesel fuel flowing through the container.

Abstract: An electrical resistor and method of making the same is disclosed wherein a ceramic substrate is coated with a relatively rough dielectric film which is subsequently coated with a thin metal film such as nichrome.