GB740647A - Improvements in and relating to submarine cables - Google Patents

Abstract

740,647. Cables. SUBMARINE CABLES, Ltd. Sept. 17, 1954 [July 3, 1953; July 15, 1953], Nos. 18598/53 and 19695/53. Class 36. In a coaxial submarine cable comprising a central stranded core of high-tensile strength, an inner conductor formed of a layer of conductive material on the surface of the core, and an outer conductor spaced from the inner conductor by a dielectric layer, the central core comprises two or more layers of wire, adjacent layers having opposite directions of lay, the angle of lay of the wires with respect to the core axis being between 5 and 12 degrees and the sum of the products (total cross-sectional area of wires in a layer) x (pitch diameter of the layer) x (size of the angle of lay) for layers in one direction being substantially equal to that for layers in the other direction. The inner conductor may be formed by wrapping a conductive tape around the core to form a closed tube which is locked to the core, either by folding the edges together to form a longitudinal seam or by tinning the core and the tape, applying the tape with an overlap and then heating to sweat it into a closed tube and bond it to the core. The outer conductor may comprise one or more conductive tapes applied over the dielectric and protected by a viscous plastic material compatible with the dielectric which closes the'gap between the tapes. A thin plastic tape is wrapped on under tension and an outer plastic sheath applied under heat and pressure so that it is bonded to the plastic tape. The dielectric material may be polythene and the viscous plastic may be polythene of low molecular weight. The plastic tape and sheath may be of polythene or polyvinyl chloride. Specification 703,782 is referred to.