GB354734A - Improvements in or relating to submarine signalling cables - Google Patents

Abstract

354,734. Cables. ELECTRICAL RESEARCH PRODUCTS, Inc., 195, Broadway, New York, U.S.A.-(Assignees of Gilbert, J. J. ; 16, Pine Street, Douglaston, New York, U.S.A.) May 12, 1930, No. 14625. Convention date, May 18, 1929. [Class 36.] In order to reduce eddy current losses, particularly in continuously loaded twin core telephone and other high frequency telephone conductors, a teredo protecting sheath comprises a large number of metal tapes of less than ¢ inch in width, or fine wires. Fig. 1 shows the cores of a twin core cable, each core being individually wrapped with teredo tapes 15. In Fig. 2, a common wire teredo protection 15 covers the cores. The cores comprise a conductor 10 with flat surrounds 11, loading tape 12 embedded in semi-liquid pressure equalizing material 12a, insulation 13, jute layers 14, 16, and armouring 18. In the construction of Fig. 1, narrow overlapped metal tapes 15 are wrapped on the insulation 13 of each core. The overlapped parts of the tapes 15 may be insulated from each other by metal oxide or by fabric impregnated with bitumen. To avoid conductive contact of the tapes 15 on one core with those on the other, the wrappings 15 on each core may be covered with fabric tape 17. In the construction of Fig. 2, a single protecting sheath comprising fine wires 15, preferably of copper or brass, is laid on a jute worming 14 served about the cores 13. The wires 15 are about 0À01 inches in diameter. The tape or wire 15 may be formed of the alloy known under the registered Trade Mark Nichrome, or of nickeliron-chromium alloys, or copper-manganese-aluminium alloys the thickness of tape used being about À004 inches. Specification 266,714, [Class 36, Electricity, Conducting &c.], is referred to.