Abstract: A method for production of a composite material comprises the incorporation of a foaming agent into a thermo-fusible fluoro-resin for providing bubbles in the thermo-fusible fluoro-resin. The thermo-fusible fluoro-resin is comminuted to a suitable size, and the comminuted thermo-fusible fluoro-resin is mixed with a polymer for surrounding and supporting the thermo-fusible fluoro-resin with the polymer. The thermo-fusible fluoro-resin is foamed after incorporation of the foaming agent. The comminuted thermo-fusible fluoro-resin is foamed after mixing with the polymer. A composite material having low permittivity comprises hollow bubbles formed of a thermo-fusible fluoro-resin and a polymer material surrounding and supporting the thermo-fusible fluoro-resin forming the hollow bubbles.

Abstract: A low permittivity connector for providing a plurality of contacts disposed substantially parallel at predetermined spacings relative to each other. Ribbon-type conductors are disposed on a low-permittivity dielectric sheet and exposed on at least one side of the sheet. Wires are contacting respective ribbon-type conductors, disposed in a longitudinal direction relative to the conductors, and projecting as pins from an edge at one end of the low-permittivity dielectric sheet. A housing holds the low-permittivity dielectric sheet, the ribbon-type conductors, and the wires by way of joining sheets and having openings in the area of the ribbon-type conductors at a second end of the low-permittivity sheet for allowing insertion of pins projected from a like connector. A flat cable comprises a plurality of wires formed of a hard cord covered by a conductive layer, plurality of ribbon-type contacts contacting respective wires and a sheet which supports the ribbon-type contacts.

Abstract: A process is provided for making a laminated board useful in printed circuitry. The process involves laminating a metal layer to at least one side of a sheet of porous, expanded polytetrafluoroethylene using an adhesive followed by compressing the polytetrafluoroethylene sheet to increase its density. The metal layer may be a metal foil or it may comprise electrical circuitry. Also provided are printed circuit boards produced by the aforesaid process.

Abstract: A solvent leak detecting sensor is provided comprising: (a) a first electrical conductor and a second electrical conductor installed on an electrically insulating substrate in the form of a detection circuit network, the conductors being exposed and separated from each other, (b) the exposed portions of the first conductor and second conductor being covered by a layer of an electrically insulating material which is both water-repellent and which is dissolvable by the solvent that is to be detected, and (c) a top layer covering the layer in "b", this top layer being both porous and electrically conductive. The layer which is both water-repellent and which is dissolvable by the solvent that is to be detected is preferably polyvinylchloride, and the top layer is preferably conductive carbon powder.

Abstract: A snorkel device for breathing under the surface of water which will allow both inhaling and exhaling of air underwater. A multiplicity of water impermeable tubes, permeable to dissolved or gaseous oxygen, allow underwater passage of oxygen into the snorkel. Preferred tube material is porous expanded polytetrafluoroethylene.

Abstract: A printed circuit is provided wherein the electrically conductive material which forms the circuit elements is embedded within a dielectric substrate. The preferred dielectric substrate is porous, expanded polytetrafluoroethylene.

Abstract: An oil leakage detection device is provided having a detection unit comprising: (a) an oil leakage detecting sensor which exhibits a positive resistance-temperature characteristic in response to changes in temperature, connected, in series, to (b) an oil leakage detecting sensor which exhibits a negative resistance-temperature characteristic in response to changes in temperature.

Abstract: An attachment ring assembly is provided for installation in drain openings. The assembly includes a cylindrical ring body installed in the drain opening, the ring body extending over the entire circumference of the discharge port of the drain opening, the ring body having a relatively small liquid-collecting opening in the lower end of the cylindrical ring. A liquid leak detecting sensor is installed in the liquid-collecting opening. A liquid leak which flows into the drain is dammed by the attachment ring assembly and channelled to flow into the liquid-collecting opening and to the sensor, thereby substantially reducing the time which would otherwise be required to detect the leak.

Abstract: An attachment bracket for attaching a liquid leakage sensor to a drain opening is provided. The attachment bracket has a funnel-shaped bracket body whose outer circumference is fitted in a liquid-tight relation inside the upper portion of the drain opening, this upper, tapered funnel portion being inclined downwardly toward a central opening leading to the drain. A generally circularly-cylindrical, "C"-shaped wall member of a prescribed height is installed on the upper funnel surface of the bracket body and extends around the circumference of the central opening of the bracket body except in the region of the opening of the "C" of the wall member, and a leak detecting sensor is attached to the bracket body within the opening of the "C" of the wall member. In use, a leak that enters the drain is blocked by the wall member and channelled by the wall member around to the opening of the "C", thereby concentrating the leak to the region of the sensor location more rapidly than would otherwise occur.

Abstract: An oil leakage sensor element is provided wherein a plurality of electrical conductors are contained within and separated from each other by a continuously porous polytetrafluoroethylene (PTFE) material containing from 15 to 40 weight percent carbon particles, the carbon particles having irregular shapes and average diameter between 10 and 30 millimicrons, at least a portion of the exterior surfaces of the carbon particles being exposed at the pore walls of the PTFE and extending into the pores. The porous PTFE material is preferably obtained by stretching an extruded, unsintered PTFE film containing the carbon particles, after removal of lubricant, to a draw ratio of 1.5 times or less. The sensor element, in use, is connected between electrodes which, in turn, are connected to an alarm device. Preferably, the sensor is connected to elongate conductors (wires) such that the direction of stretch of the material is aligned with the lengthwise direction of the conductors.

Abstract: A reinforced porous dielectric sheet of expanded polytetrafluoroethylene is provided wherein solid plastic reinforcement elements in the form of circular columns or wall-like partitions extending through the dielectric sheet from one surface to the other are distributed within the sheet. The reinforced sheet is useful as a substrate for printed circuit boards. The reinforcement elements are preferably of a tetrafluoroethylene/ethylene copolymer or an epoxy resin.

Abstract: Means are provided for radiating electromagnetic waves from a receiving end zone of a dielectric line for transmitting electromagnetic waves without the need for a metal horn antenna or a metal waveguide, and matching problems are thereby substantially avoided. Said means are provided by shaping the end of the line to specified contours, by varying the dielectric constant of the material of the line in a gradient longitudinally near the end zone of the line, and by arranging a reflecting mirror or lens to receive the waves emitted from the line. This waveguide is useful in wireless communications, radar transmission and similar applications.

Abstract: An adaptor is provided for effecting a small radius-of-curvature bend in a relatively large diameter coaxial cable. The adaptor comprises a central, preferably plastic, bellows-like protective element, at either end of which is attached a connector for attachment externally to a relatively large diameter coaxial cable, each connector attached internally to a flexible, relatively small diameter coaxial cable which extends from one connector to the other connector through the protective bellows-like element. Because of the bellows-like element and the relatively small diameter of the flexible coaxial cable in the adaptor, a small radius-of-curvature effective bend in the relatively large diameter coaxial cable assembly can be achieved without significant transmission losses.

Abstract: A cooling device is provided for use in cooling surrounding human tissue during hyperthermia treatment of a cancerous tumor. The device comprises at least one tube constructed of a fluororesin having continuous pores, such as porous, expanded polytetrafluoroethylene, placed in a desired configuration adjacent the tissue to be cooled, and through which flows a coolant. Microwaves used in hyperthermia treatment of cancerous tumors can pass through the device and heat the tumor to be treated to a higher degree than heretofore possible because the adjacent noncancerous tissue can now be cooled. Because the tube is porous, the cooling effect is pronounced.

Abstract: A printed circuit board is provided wherein a composite metal layer is affixed to at least one surface of a flexible dielectric substrate, the composite metal layer comprising an inner aluminum layer and an outer copper layer. Owing to the relatively high elongation of the aluminum layer, when the printed circuit board is flexed the circuit thereon does not crack.

Abstract: A phase-adjustable coaxial cable connector is provided. Phase adjustability is provided by means which increase or decrease the slack in a slackened portion of the center conductor of a coaxial cable which extends into the connector.

Abstract: A multilayer printed circuit board is provided comprising a plurality of printed circuit boards laminated together, each board being separated from an adjacent board by a layer of a dielectric of porous, expanded polytetrafluoroethylene (PTFE). The dielectric layer may have an adhesive on its surface(s) affixed as a layer or in a pattern of dots. Alternatively, an adhesive may be impregnated within the pores of the porous dielectric. In a preferred embodiment, the dielectric has additional openings or through holes in it, in additon to the pores of the porous dielectric.

Abstract: A temperature sensor is provided comprising an electrical temperature sensing element such as a thermistor and a pair of high-resistance conductors of conductive fluorocarbon resin which are electrically connected to the electrical temperature sensing element. The conductors of conductive fluorocarbon resin are disposed on opposite surfaces of a body of fluorocarbon resin. The electrical temperature sensing element may be sandwiched between the pair of high-resistance conductors. Alternatively, the temperature sensor comprises a temperature sensing element held in place and in electrical contact between a pair of conductive fluorocarbon sheets, the sheets being fused one to each side of an electrically insulative sheet of fluorocarbon resin, thereby forming a laminated composite in sheet form, the laminate being vertically separated along its longitudinal axis remote from the temperature sensing element, thereby providing a 4-lead temperature sensor.

Abstract: An optical transmission line is provided comprising an elongate light guide surrounded by a layer of a porous plastic, preferably expanded, porous polytetrafluoroethylene, and having at least one reinforcing strand, such as a wire, positioned outside of the porous plastic layer, this entire assembly encased in a resin sheath having a rectangular cross-section such that the light guide is positioned at the center of the cross-section of the resin sheath along the length of this transmission line. Multiconductor flat cable is provided by bonding a multiplicity of these optical transmission lines together. The transmission line is useful for transmitting optical energy signals.

Abstract: A phase-adjustable coaxial cable connector is provided which adjusts the length of the phase path of the system without changing the length of the connector. The electrical path length is adjusted by relative rotation of electrical conductors in the connector.