GB538360A - Means for preventing leakage of fluid along the interior of electric cables - Google Patents

Abstract

538,360. Cables. BERESFORD & SON, Ltd., J., and GOLD, R. L. Oct. 27, 1939, No. 28857. [Class 36] Means for preventing leakage of fluid along the interior of a cable or cables comprises the combination with a bared part of the conductor which has been rendered impervious by tinning or otherwise, of a rubber sleeve moulded round the conductor after the latter has been coated with a binding agent. The invention is applicable to a cable-end or to intermediate parts of a cable, and can also be applied to joints between cable-sections. Fig. 1 shows a 3-core cable passing through the stuffing-box b of a submersible-pump motor. Insulation e is removed from the outer sheath and each inner sheath d is removed from its core c so that the sheaths project unequal distances from the main insulation e. The cores c are rendered impervious by tinning so as to fill the interstices between the strands. With larger cores, one or more inner strands may be replaced by a solid rod g with pointed ends, before tinning. One or more perforated or slotted discs h of cured or partly cured rubber are fitted over the cores to space them and a vulcanized-rubber end block i applied to the free ends. A sleeve k of uncured rubber is then moulded round and between the cores and over the sheath-ends d, perfect adhesion between it and the cores and a metal sleeve m being obtained by covering'the latter with a binding agent such as uncured hard rubber or a solution or dispersion of hard rubber or rubber derivatives. The whole is then vulcanized. To make a seal between the cable and box b, as in Specification 538,357, [Group XXVI], jointing material n is placed between metal pressure rings p, q, and pressure applied by an annular nut s. In Fig. 3 the joint between a 3-core round cable, a and a 3-core flat cable a<1> has a seal applied by treating, as already described, the insulation at the ends of both cables, the cores being then spliced. together and tinned. The core-spacers comprise a wrapping of a composite sheet comprising a sheet u of cured rubber and one t of uncured rubber next the core. The process is then carried out as above described, except that the sleeve k k envelops the ends of the main insulation of both cables. The Provisional Specification states also that endwise pressure may be applied to the rubber in moulding in order to fill all interstices.