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: 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: 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: 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.

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 high speed electrical transmission line is provided comprising a signal conductor having an open cell, continuously porous, polymeric insulating material surrounding the conductor, the insulating material having a plurality of openings fused therein, the walls of the openings being solid, fused polymer which provide compressive strength for the otherwise highly compressible porous insulating material. The preferred polymer is expanded, porous polytetrafluoroethylene. The openings may be formed by a laser or by other means.

Abstract: An improved flexible shielded electrical coaxial cable is provided having a shielding layer surrounding a core line, wherein the shielding layer comprises a plurality of metal wires helically overwrapped about the core line, adjacent wraps being in close contact, wherein the improvement comprises at least one strip interwoven in a stitching manner among the metal wires of the shielding layer. The strip is preferably a strip of expanded, porous polytetrafluoroethylene. The cable is highly flexible and useful in robots, for example.

Abstract: A connector for a flat cable having a plurality of conductors disposed parallel to and apart from each other within an insulator is provided, which connector comprises a cover having a channel adapted to support a terminal portion of said flat cable in a state wherein said terminal portion is bent, and a connector body having a plurality of contact terminals corresponding to the number of said conductors, said contact terminals extending through said connector body and being inserted into said bent terminal portion supported by said cover in such a manner that said contact terminals are in electrical contact with corresponding conductors, respectively, said connector body being adapted to clamp said cable having said contact terminals inserted thereinto between said connector body and said cover.

Abstract: A detector for detecting leaks of a corrosive liquid such as strong acids or bases is provided comprising a light guide core having a covering which generates heat upon contact with the liquid to the detected, thereby changing the light transmissivity of the light guide, which change can be measured. The covering comprises a porous polymer having a salt within its pores such as an ammonium salt which dissolves in the liquid to be detected and generates heat thereby.

Abstract: An electrical transmission unit line is provided comprising a porous dielectric layer having positioned on one side thereof a pair of narrow, parallel elongated electrical conductors and on the other side thereof, opposite the pair of conductors and extending transversely across both wires of the pair and parallel thereto, a wide ground conductor. An electrical transmission line having a plurality of such unit lines is also provided. The porous dielectric is preferably porous, expanded polytetrafluoroethylene. The transmission lines are covered with an electrically insulating material, preferably a nonporous plastic.

Abstract: An electrical transmission line of the twisted pair of coaxial cable type is provided. One line has a center conductor, a porous plastic dielectric disposed around the outer periphery of the conductor, the dielectric having specific gravity of 0.5 or less, and having a plastic dielectric sheath disposed around the outer periphery of the porous dielectric, the outer sheath having a melting temperature which is 60% or less than the melting temperature of the porous plastic dielectric. The porous plastic dielectric may be in tape form helically wrapped around the conductor, preferably at a wrap angle of 20 degrees or less. The preferred porous dielectric is expanded polytetrafluoroethylene.

Abstract: A dielectric sheet material useful in electronics applications is provided. The material preferably is porous, expanded polytetrafluoroethylene (PTFE) having a plurality of through-holes. The walls of the through-holes are solid, sintered PTFE which impart a high degree of compressive strength to the otherwise highly compressible porous PTFE. The through-holes having solid walls may be formed in the material by a laser or by other means.

Abstract: A coaxial cable and a bare wire are aligned in parallel relationship and affixed within insulation covers which have openings therein so as to partly expose both the bare wire and the outer conductor of the coaxial cable at the atmosphere, forming a leak detecting sensor. By the use of resistance meters, the core wire of the coaxial cable is utilized to detect both the presence and the location of a leak.