Abstract: A sensor for detecting leaks of a corrosive liquid is provided comprising a pair of plate electrodes made of a conductive metal which is corroded by the liquid to be detected spaced apart and separated by an inner sheet of an electrically insulating material, the inner sheet having a plurality of through-holes, this entire construction being sealingly encased between a pair of outer insulating sheets, at least one of which has a plurality of through-holes. In use, if a leak occurs the liquid passes through the through-holes in the outer insulating sheet, dissolves a portion of one electrode and passes through the through-holes in the inner sheet to the second electrode, causing a short circuit resulting in a rapid and accurately measurable decrease in the resistance in the circuit and, therefore, detection of the leak.

Abstract: An electrical transmission line is provided comprising at least one elongate signal conductor, one or more other conductors placed away from and substantially parallel to said signal conductor, all conductors encased in an outer insulating resin covering having a rectangular cross-section, the signal conductor(s) being further encased in an inner insulating porous resin covering, the porous resin covering having an electrical shielding layer thereover.

Abstract: A sheet or tube of fluororesin material having continuous pores, particularly polytetrafluoroethylene, has a nap raised on at least one surface thereof, and is suitable for prosthetic use as a patch, or an artificial blood vessel. A method of manufacturing such napped fluororesin material comprises impregnating fluororesin material having continuous pores with water, freezing it, raising a nap thereon, and defrosting and dewatering it.

Abstract: A liquid leak detecting sensor in the form of a coaxial cable assembly is provided in which means are provided for enhancing the passage of leaks from the outer surface of the outer conductor into the sensing layer which separates the inner and outer conductors. The change in permittivity of the sensing layer caused by the leak enables rapid detection of the location of the leak along the cable.

Abstract: A material for use as a gaseous diffusion electrode is provided. The material has improved durability resulting in long life. the material comprises a composite of a first layer of polytetrafluoroethylene (PTFE) containing a filler of a powdered electroconductive substance and a second layer of PTFE in bonded laminar contact with the first layer. The second layer preferably contains no electroconductive filler. The first and second layers are bonded together under pressure to form an intermediate composite and this intermediate composite is stretched, to produce the material of the invention which is a composite layered product of expanded PTFE having nodes interconnected by fibrils, one layer containing electroconductive material and the second layer preferably containing no electroconductive material. A catalytic substance can be incorporated onto or into at least the first layer by either deposition or by a filler of catalytic powder for use as the gas diffusing electrode of the invention.

Abstract: An improved, highly flexible flat multi-conductor electrical cable is provided, useful for example in robots wherein such cables may be flexed many times, comprising a plurality of conductor assemblies held in parallel relationship between layers of insulating coverings, the improvement comprising conductor assemblies having an elongate, non-conductive center core filament helically overwrapped along its longitudinal dimension by a first conductor in foil or tape form, such as copper foil, this first tape conductor having an outer covering of a conductive, low-friction material, the conductive covering being helically overwrapped along its longitudinal dimension by a second conductor in foil or tape form, such as copper foil, the second foil conductor being wrapped in a lay opposite to that of the first conductor, i.e. if one foil conductor is "S" wrapped, the other foil conductor is "Z" wrapped.

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 shaped article having a synthetic resinous body and a thin fluoropolymer weld layer on its surface is formed by a process which comprises heating a heat conductive metallic core member, forming a thin fluoropolymer weld layer on the surface of the core member, treating the exposed surface of the fluoropolymer layer, forming a synthetic resinous body on the outer, treated surface of the fluoropolymer layer and removing the core member, such as by dissolving. In the shaped article thus produced, a thin fluoropolymer weld layer is formed on the surface of the synthetic resinous body, and the thickness of the fluoropolymer coating can be reduced. This permits the production of shaped articles at low cost and having high mechanical strength, even for complicated shapes. According to the invention, it is possible to produce articles having complex shapes such as corrosion resistant vessels, molds having good release characteristics, and so forth, at a comparatively low cost.

Abstract: A method of manufacturing a porous tetrafluoroethylene tube comprises forming a sheet of tetrafluoroethylene containing a lubricant, winding it into a tubular shape, wrapping reinforcing material about the tubular shape to form a tubular product, rolling the tubular product so that it may have a uniform wall thickness, preheating the tubular product at a temperature lower than 327.degree. C., stretching the tubular product longitudinally, and heating it at a temperature higher than 327.degree. C., while holding it in its stretched position. The method may also be used to manufacture a tube containing 15 to 95% by weight of a filler.

Abstract: Reinforced easily moldable plastics are provided wherein particles of stretched porous polymer are incorporated into a plastic molding resin material to improve its physical properties without detracting from moldability. Particles or fragments of porous stretched forms of polyethylene, polypropylene, or polytetrafluoroethylene, are incorporated into a matrix of polytetrafluoroethylene polyvinylidene fluoride, or a copolymer of tetrafluoroethylene with perfluoroalkyl vinyl ether, hexafluoropropylene, ethylene, or trifluorochloroethylene.

Abstract: A new strip line cable is provided comprising a dielectric in tape form made of a porous, crystalline polymer and one or more pairs of electrical conductors, each pair of conductors having one conductor located on one side of said tape and the other conductor located on the opposite side of said tape and in substantially parallel relationship to the first conductor of the pair, the pairs of conductors being arranged in substantially parallel transverse relationship across said tape, and insulating layers made of a suitable non-porous plastic material placed over the conductors to affix them to said dielectric tape and encapsulate the cable assembly. The preferred tape dielectric is expanded, porous polytetrafluoroethylene.

Abstract: A colored, porous fluorocarbon material is provided wherein a porous layer of a colored dyeing-site resin is formed on all surfaces of the fluorocarbon material. This new material is made by a process whereby an auxiliary solvent which does not readily dissolve a dyeing-site resin, if at all, is added to a solution of the dyeing-site resin in a main solvent, and this is coated onto the surfaces of the fluorocarbon material and dried. The material may be dyed by adding dyestuff to the aforesaid solution or it may be dyed after coating and drying. The coated fluorocarbon material can be stretched.