Abstract: The present invention relates to the technical field of fluid heater devices, and more particularly to an electric cable structure of a composite construction adapted for use as an electric immersion heater for use in electroplating, metal preparation and finishing applications and the like, and more particularly relates to a new and novel, flexible cable structure of small diameter which can be quickly and easily produced by continuous fabricating techniques into indefinite lengths, and which may be thereafter severed into predetermined lengths for various immersion heater applications.

Abstract: A heat sensitive cable operable over a temperature range of between approximately -20.degree. F. and 1650.degree. F. The cable includes a tubular metallic sheath which is substantially temperature resistant and moisture impervious. It also includes a mass of compacted insulation material filling the sheath and having an insulation resistance variable with temperature in the range of between approximately 100 and 50,000 ohms. The cable further includes at least one thermoelectric conductor positioned within the insulation material filling the sheath. A method of manufacturing the cable includes the step of preparing the insulation material and advancing the thermoelectric conductor through a given region. It also includes the step of advancing a strip of flat metal material past apparatus for forming and welding a tubular sheath surrounding the given region.

Abstract: The invention contemplates a unitary magnetically sensitive circuit element or network and a flexibly articulatable elongate assembly of a plurality of such elements or networks, with electrical interconnection of the same, such assembly being inherently suited to precision operation as a function of length, whatever the length selected for a particular application or use. In one application to liquid-depth indication within a tank, the longate assembly is merely inserted into the tube along which a float-borne permanent magnet is guided, and the magnetically sensitive element of each successive unit is actuated as the float tracks liquid level and is displaced from actuating relation with one and then to the nextadjacent one of the circuit-element units. The connection of circuit-element units is such that electrical-resistance observation from one end of the assembly provides a direct indication of the liquid level at which the float magnet is currently operative.

Abstract: A heating electric wire is provided having a heating portion electrically connected to a lead portion, the heating portion being a bundle of a plurality of elongate, electrically insulating tension members having a heating layer around the periphery of the bundle of tension members, the lead portion being a bundle of a plurality of elongate, electrical conducting wires, at least a portion of the insulating tension members being coupled to at least a portion of the conducting wires in the connection region between the heating and lead portions, the entire assembly having a heat resistant sheath around its periphery.

Abstract: A flexible heating element is suggested to be made on a continuous basis, so that desired length can be cut therefrom and includes individual, electrically insulated feeder lines and a heating being interlooped in interweaving fashion with the feeder lines, there being discrete locations of the feeder lines from which the insulation has been removed for making contact with the heating conductor for supplying power thereto.

Abstract: A transmission line for the transmission of electrical energy and signals, including at least one electrical conductor exhibiting high frequency skin effect; a low conductivity magnetic composite layer surrounding the at least one conductor and exhibiting an inductance characteristic; a resistive layer coupled to the magnetic composite layer and having a predetermined capacitance relative to ground potential, the resistive layer exhibiting a longitudinal resistance characteristic matched at least to the inductance characteristic of the magnetic composite layer to obtain a correspondingly determined low pass frequency characteristic wherein within a predetermined transition frequency range, current flow switches from the at least one conductor to the resistive layer.

Abstract: The leads to a heater for an electrothermal hydrazine monopropellant thruster comprise tungsten conductors wrapped with smaller diameter tungsten support wire and insulated with beads of alumina (Al.sub.2 O.sub.3). A transition section connects the leads to regular leads. An attaching support wire is attached to the heater at one end and to the transition section at the other end. The insulated conductors and attaching wire are wrapped together with nickel ribbon to form a sheath.

Abstract: A fire detector is provided with an electric insulator consisting of short segments of preferably a ceramic pipe disposed end-to-end within the space between an inside cylindrical electrode and cylindrical outside electrode. The inside electrode together with the insulator segments are covered with a thin salt-based layer and are disposed in the interior of the outside electrode so that between the insulator segments and the internal wall of the outside electrode an air space is formed along the length of the detector, whereby the insulator segments each provide a point-type contact between the internal wall of the outside electrode and the thin salt-based layer.

Abstract: A heat sensitive cable operable over a temperature range of between approximately -20.degree. F. and 1650.degree. F. The cable includes a tubular metallic sheath which is substantially temperature resistant and moisture impervious. It also includes a mass of compacted insulation material filling the sheath and having an insulation resistance variable with temperature in the range of between approximately 100 and 50,000 ohms. The cable further includes at least one thermoelectric conductor positioned within the insulation material filling the sheath. A method of manufacturing the cable includes the step of preparing the insulation material and advancing the thermoelectric conductor through a given region. It also includes the step of advancing a strip of flat metal material past apparatus for forming and welding a tubular sheath surrounding the given region.

Abstract: A temperature threshold detector (10) comprises a first electrical conductor (11) and a second electrical conductor (12), which are separated by a spacing structure (13). The first and second electrical conductors (11 and 12) are made of metals that are dissimilar from each other in terms of oxidation potentials or thermally generated electromotive force. The spacing structure (13) is made of a material whose electrical resistivity is temperature dependent so that, when exposed to a temperature below a predetermined threshold value, the spacing structure (13) provides electrical isolation between the first and second electrical conductors (11 and 12). However, when exposed to a temperature above the predetermined threshold value, the spacing structure (13) enables an electromotive force to develop across the first and second conductors (11 and 12). This electromotive force is indicative of temperature rise above the predetermined threshold.

Abstract: Self-regulating electrical strip heaters which comprise at least two elongate conductors and at least one elongate resistive heating strip which contacts the conductors alternately as it progresses down the length of the heater. The conductors can be separated from each other by an insulating strip, with the heating strip being wrapped around the conductors and the insulating strip. Alternatively the conductors can be wrapped around a core comprising the heating strip and an insulating strip. The self-regulating characteistic of the heater preferably results from use of a PTC material, particularly a PTC conductive polymer in the heating strip. Preferably the junctions between the conductors and the heating strip are coated with a low resistivity conductive polymer composition.

Abstract: A strip heater for wrapping around and applying heat to elongate generally cylindrical objects has a thin, flexible, elongate fiber reinforced base with a uniform width along the majority of its length, resistance wire insulated within the base across a uniform portion of the width of the base and a flexible insulating layer having a width equal to that of the portion of the base containing the resistance wire and overlying only a portion of one surface of the base. The heater is designed to be wrapped around a cylindrical object, such as a communications cable, with the thicker insulating portions overlying the portions not having the insulating layer and abutting itself in adjacent turns around the object to position the portions of the base containing the resistance wire adjacent each other in the spiral adjacent the object.

Abstract: Permeation of water between inner and outer insulating jackets of an elongate electrical heater or other device along a metallic braid between the jackets is limited by means of a water-blocking section. The water-blocking section is generally placed near the connected end of the device to prevent water from reaching the connection. In the water-blocking section, the outer jacket is removed and an insulating sleeve, preferably a heat-shrunk polymeric sleeve, is placed over the exposed length of the inner jacket and the ends of the outer jacket. A water-proof sealing material is placed between the sleeve and part only of the exposed inner jacket. In this way, water which permeates between the jackets to the water-blocking section is prevented from passing through the section but is permitted to escape from the device.

Abstract: An ignition cable for supplying voltage to the spark plugs of an internal combustion engine, the cable having a low electrostatic capacity such that it does not produce noise in an FM radio frequency band. A central reinforcing string made of aramido-type fibers is covered by a ferrite core. A resistance wire having 8,000-14,000 turns/meter is wound onto the core. The assembly is then coated with a polyolefin insulation layer, a crossed-fiber reinforcement layer, and a silicon sheath, respectively.

Abstract: Compositions which cure to electrically conductive silicone elastomers containing greater than 2 percent by weight of phenyl radicals, are disclosed. The compositions comprise a mixture of polydiorganosiloxane and greater than 15 percent by weight of electrically conductive carbonaceous particles of less than 20 micrometers average diameter. Electrically conductive members of controlled resistivity are manufactured using these compositions. These electrically conductive members are useful as the core for improved automotive ignition cable. The ignition cable has a long useful life.

Abstract: A modular heating cable assembly having two cold wires extending the length thereof and a resistance heating wire interconnecting the two wires. The portion of the two wires anterior to the heating wire forms a cold lead, and an element for interrupting the circuit to the heating wire is disposed in one of the wires of the cold lead. The assembly may consist of a cold lead module and one or more heating cable modules, and the element for interrupting the current may be disposed either in the cold lead or in a separate unit disposed between the cold lead module and the heating module.

Abstract: A method and apparatus for parallel-type heating cables. In accordance with the present invention a heating core element is formed by connecting two essentially parallel bus wires with a plurality of electrically conductive splices to a centrally disposed resistive element and around which heating core element a protective sheath is formed. The present invention permits this heating core element to be formed by splicing the spaced apart, essentially parallel wire elements followed by a single extrusion application of a protective sheath.

Abstract: A process for forming ignition cable core and a product of the process are described wherein multiple strength filaments are individually coated with an electrically conductive, curable elastomeric material, a common overcoating surrounding the mixture, then cabled together and again coated with the individually coated strength filaments in order to form the core for an ignition cable which is characterized by improved resistance to separation between the filament and conductive coating, for example, when the ignition cable core is stripped for electrical termination.

Abstract: A high voltage ignition cable is described comprising a resistive-conductor core, an insulator layer, and a jacket, wherein the resistive-conductor core comprises a tension member, a semiconductive internal layer, a semiconductive external layer, and a stripping layer interposed between the semiconductive internal layer and the semiconductive external layer.

Abstract: A composite electrically conductive cable assembly for use as an ignition cable or the like. The assembly comprises an electrically conductive core comprising a plurality of mechanically and electrically continuous graphite filaments, and an electrically insulating elastomeric jacket which surrounds and envelopes the said filaments. The filaments preferably comprise graphitized polyacrylonitrile.

Abstract: A high voltage ignition cable is described comprising a resistive-conductor core, an insulator layer provided thereon, and a jacket, wherein said insulator layer comprises a cross-linked product of a polymer composition consisting of crystalline polyethylene and a non-crystalline olefin polymer.

Abstract: A high voltage ignition cable having low capacitance comprising a resistive-conductor core, an insulator layer, and a jacket, wherein the resistive-conductor core comprises a tension member prepared by intertwining a plurality of polyaramide fiber bundles around a central polyaramide fiber bundle, is described.

Abstract: A method and apparatus for parallel-type heating cables. In accordance with the present invention a heating core element is formed by connecting two essentially parallel bus wires with a plurality of electrically conductive splices to a centrally disposed resistive element and around which heating core element a protective sheath is formed. The present invention permits this heating core element to be formed by splicing the spaced apart, essentially parallel wire elements followed by a single extrusion application of a protective sheath.

Abstract: A process for preparing a high voltage-ignition cable having a low electrostatic capacity comprising a resistive-conductor core, an insulator layer and a jacket layer, which comprises preparing a resistive-conductor core comprising a fiber bundle and a semiconductive material provided on at least on the circumferential surface thereof, extrusion coating a polyolefin resin on the circumferential surface of the resistive-conductor core to form an insulator layer, irradiating the insulator layer with electron beam to effect cross-linking of the resin, extrusion coating a polyolefin resin, without providing a reinforcing layer or after providing a reinforcing layer, on the cross-linked insulator to form a jacket and irradiating the jacket with electron beam.

Abstract: The invention relates to novel electrical devices which are useful for example as heaters and temperature sensors, and which comprise at least two electrodes, at least one PTC element, at least one relatively constant wattage element, and at least one current-directing element which directs the current, when the device is first connected to a source of electrical power, so that the effective initial resistance of the device is greater than it would be in the absence of said element. Thus the invention provides a solution to the problem of current inrush in application of PTC devices in which substantial current passes through the device at operating temperatures. The invention also includes the use of the novel devices in applications in which current inrush is not a problem.

Abstract: A heating element for use in an electric blanket or the like including conductors spaced apart in a positive temperature coefficient (PTC) material which serves as a self-limiting heater. The conductors are separated by a spacer which prevents the conductors from engaging each other when the PTC material softens or melts during annealing thereof. A coating of material having a higher melting point than the PTC material is placed over the PTC material to maintain its shape during the annealing process.

Abstract: A heating cable having spaced helically wound conductor wires separated by a layer of positive temperature coefficient material which functions as a self-limiting heating element. At least one of the conductor wires is helically disposed on a stranded core of insulating fibers which have been coated and impregnated with conductive carbon.

Abstract: A heater cable with coaxial inner and outer conductors and an intermediately disposed resistance heater. The heater is spaced from the inner conductor by radially extending alternating conductive and non-conductive separators with current being delivered to the heater by the conductive separators. The heater is deformed so as to contact the outer conductor at spaced locations to thereby define plural parallel heating circuits.

Abstract: A fault indicator for indicating the occurrence of a fault current in an electrical conductor includes a reset circuit operable from an external electrical excitation source. The external source is connected to the reset circuit by a cable formed from a flexible electrically insulating tubing segment within the lumen of which an electrically conductive coating is disposed. The resulting high impedance electrical interconnection reduces the danger of electrical shock from inadvertant contact with the cable or the fault indicator circuitry, and precludes the source from being adversely affected should the cable become shorted to ground.

Abstract: Described herein are self-regulating conductive articles comprised of an extruded length of polymeric material containing not more than about 15% by weight conductive carbon black, the resistivity of the extrudate following prolonged exposure to temperatures in excess of the crystalline melting point or range of the polymeric matrix in which the black content satisfies the equation:2L+5 log.sub.10 R.ltoreq.45.Wherein L is percent by weight black and R is resistivity of the extrudate expressed in ohm-cm. The articles exhibit room temperature resistivity in the range from about 5 to 100,000 ohm-cm and may be employed, e.g., in heat tracing and thermostating applications.

Abstract: A heating element for use in an electric blanket or the like including conductors spaced apart in a positive temperature coefficient (PTC) material which serves as a self-limiting heater. The conductors are separated by a spacer which prevents the conductors from engaging each other when the PTC material softens or melts during annealing thereof. A coating of material having a higher melting point than the PTC material is placed over the PTC material to maintain its shape during the annealing process.

Abstract: Electrically parallel but positionally serial, helically wound segments of heating wire in a cable are each controlled by a chip (thermistor) and are connected to the cable proper by wrapping around notches formed in the insulation of the cable proper at first one side and then the other of the cable. The inner and outer-faces of each chip are connected into each segment by direct contact or by leads at spaced points between which the heating wire is severed. An extruded casing is shrunk-fit over the other parts.

Abstract: The invention relates to novel electrical devices which are useful for example as heaters and temperature sensors, and which comprise at least two electrodes, at least one PTC element, at least one relatively constant wattage element, and at least one current-directing element which directs the current, when the device is first connected to a source of electrical power, so that the effective initial resistance of the device is greater than it would be in the absence of said element. Thus the invention provides a solution to the problem of current inrush in applications of PTC devices in which substantial current passes through the device at operating temperatures. The invention also includes the use of the novel devices in applications in which current inrush is not a problem.

Abstract: A heater immersible in liquids such as water suitable for water beds and a method for producing the heater are disclosed. The heater includes two-spaced apart metallic electrodes interconnected by a conductive polymeric matrix. A water-impermable barrier completely surrounds the polymeric matrix. A jacket of plasticized polyvinyl chloride can be placed around the barrier. The barrier also prevents plasticizer from the polyvinyl chloride from penetrating and damaging the conductive polymeric matrix.

Abstract: Disclosed are improved melt processable, self-temperature regulating, irradiation cross-linkable, electrically semi-conductive polymeric compositions which in conjunction with annealing at a temperature at or above their melt point temperatures subsequent to their having been radiation cross-linked provide for improved self-temperature regulating electrical heating devices including flexible electrical heating cables. Heating cables made in accordance with the invention comprise two or more elongate substantially parallel spaced-apart electrical conductors that are electrically inter-connected by means of extruded forms of the compositions which have been annealed at a temperature at or above their melt point temperatures prior and subsequent to their having been cross-linked by irradiation.

Abstract: A heating tube adapted to electrically heat a fluid carried therethrough includes an inner tubular layer of polytetrafluoroethylene, a second tubular layer surrounding the inner layer and being formed of a homogeneous mixture of polytetrafluoroethylene and electrically conductive carbon, and a third layer surrounding the second layer and being formed of polytetrafluoroethylene. The three layers are coextruded together. The third layer is cut away at at least two circumferential points and the exposed second layer is there provided with a sintered coating for finely divided silver and finely divided polytetrafluoroethylene. The sintered coating is then wrapped with a silicone resin tape containing dispersed silver particles and a metal ring is then fitted over the silicone resin tape thereby forming an electrical terminal for the heating tube.

Abstract: A high-voltage electrical cable comprising a core of alternating solid non-brittle resistors and flexible conductive links sheathed in a moderately flexible dielectric material has the relative physical dimensions of the components selected such that the mechanical stresses in the assembly are minimized if any loop in the cable were inadvertently pulled in such a way as to put a kink in the cable.

Abstract: A semi-conductive coating for glass fibers is disclosed, the coating comprising at least one polyacrylate emulsion, a conductive carbon black dispersion and a thixotropic gelling agent. The coating being suitable for application to glass fiber roving employed to produce electrical cables.

Abstract: An electrical branch circuit for use as in a swingable door of an automotive vehicle is shown having an electrical load connected to first ends of electrical conductors which, in turn, at their respective other ends are connected to terminal means mechanically connectable to related circuit means, resistor means is connected into at least one of the electrical conductors as to be generally between the electrical load and the terminal means.

Abstract: An electric space heating apparatus consisting of a plurality of sections having box-like portions which by means of middle pieces are interconnected in such a way that the apparatus can extend along all the walls of the room and the zig-zag electric heating elements in the apparatus sections can be fed continuously through the complete apparatus, the apparatus being adapted to deliver the heat to the space by approximately 65-75 per cent radiation and approximately 25-35 per cent convection to circulating air, said apparatus can be easily mounted by persons without special education and authorization.

Abstract: An electrical heating cable which limits power output once an established temperature limit is reached. The cable includes heating elements in the form of temperature-sensitive variable resistance elements electrically connected in parallel between two supply bases at spaced positions along the length of the buses. The heating elements not only serve to generate heat for heating but also undergo a substantial positive increase in resistivity when the temperature of the cable nears the established temperature limit. The increase in resistivity substantially reduces the heat-generating current in the cable to limit the power output to within established heat limits.

Abstract: A heat treating appliance coilable about steel piping for heating it before or relieving stresses in it after welding comprises an elongate reticulate sleeve of interlaced heat and oxidation wire having lengths of electrical heating cable each doubled back along itself and fixed inside and along the sleeve so as to form cable legs spaced apart in the sleeve and having terminal portions extending outside it, from respective openings near one end thereof, for connection with a current source. The sleeve has end portions extending beyond the cables therein, and each bent back upon itself into a loop, for securing the appliance in place on the structure to be heat treated.

Abstract: A rigid electrical heating element having a thin, rigid, electrically insulating, air-impervious layer and a thick, insulating polyurethane layer formed in situ connected to said rigid layer by a conducting film based upon a synthetic resin, electrically conducting particles and potassium silicate or sodium silicate. Electrodes and corresponding electrical connections are mounted on the film after it has been applied by deposition of an aqueous plastic dispersion of said resin particles and silicate material. The silicates being present in the heating film in sufficient quantity to protect the heating film from attack by the starting reaction components of the polyurethane layer. The rigid layer may be a synthetic resin panel having a decorative heat irradiating surface.

Abstract: A special purpose electrical connector. It is for connecting an end of a resistive type of electrical conductor so as to have maximum electrical and mechanical properties.The resistive conductor has a resilient material core of desired resistivity which is surrounded by an insulator. A pair of conductive material wires are applied in a cooperative manner with one wire extending doubled for a substantial distance into the core. The other wire wraps around the outside of the insulator and pierces through to join the first within the resilient core, before extending axially beyond the end of the core and insulation.

Abstract: A high-temperature parallel-resistance pipe heater is described which is capable of being maintained at a high temperature level of approximately 600.degree. F on a sustained basis and is capable of withstanding temporary occasional heating up to 1,000.degree. F. A twisted pair of flexible electrical conductors with micaceous and fiberglass braid insulation layers have short segments stripped bare on alternate conductors at uniformly spaced intervals along their length, the conductors each including multiple fine nickel-clad copper strands, and a nickel-alloy resistance wire is helically wound around the twisted pair with two bights of the resistance wire engaging many of the strands in each bared segment for establishing numerous points of high unit area pressure contact at the junction between conductor and resistance wire. An anti-fraying agent on the fiberglass braid prevents the fibers from interfering with these points of contact.

Abstract: An electrical insulation coated metallic wire consisting of a releasing layer coated on a metallic wire and an insulating layer superposed on the releasing layer. The insulating layer is formed by coating and baking an insulating varnish on the releasing layer. The electrical insulation coated metallic wire is used as an insulated conductive wire or an insulated resistance wire, the former using an electric conductor as the metallic wire and the latter using an electric-resistive substance as the metallic wire.

Abstract: The disclosed conductor includes a core, having a plurality of conductive glass fibers, an overwrap of non-conductive glass strands wound under tension around the core and a semi-conductive overcoat, preferably of polytetrafluoroethylene having suspended therein conductive powders, and silica. The overwrap includes distinct windings, rather than a braid, which securely retains the fibers in a cylindrical core of uniform cross-section.

Abstract: Improved forms of electric resistance elements or resistors may be made from semiconducting organic-refractory oxide fibers, as for example drawn alumina fibers which have been subjected to contact with a pyrolyzable organic substance at a temperature above about 400.degree. C. A few, or a large number of the semiconductive fibers, can be used in a group or bundle form to provide a desired resistance for a particular resistor. A preferred form of resistance element will cover the fibers in a quartz tube or other suitable encapsulating material to preclude moisture problems.

Abstract: Crosslinkable ethylene-vinyl acetate copolymer resins are rendered amenable to forming adherent laminates with crosslinkable silicone rubber by coating the surface of the ethylene-vinyl acetate resin with a solution of a silane or a member of the class of compounds known as polyfunctional monomers prior to adhering the resin to the silicone rubber.

Abstract: Crosslinkable ethylene-vinyl acetate copolymer resins are rendered amenable to forming adherent laminates with cross-linkable silicone rubber by dusting the surface of either the resin or rubber, or both, with a bonding agent.