GB1195788A - Improvements in or relating to the Making of Joints in Oil-filled Conductors - Google Patents

Abstract

1,195,788. Direct connections. PIRELLI S.p.A. 18 Oct., 1968 [17 Nov., 1967], No. 49413/68. Heading H2E. [Also in Division B3] A method of making a joint between the core of an oil-filled cable and a second conductor by welding, allows continuous oil flow to be maintained during the welding process and yet prevents oil from reaching the point of welding. The oil-impregnated insulation 2 and outer protective insulation 3 of the cable are cut back to expose length 1 of stranded inner conductor core, and sealed by a winding 4 of adhesive tape, and an oil flow tube 16 fitted with sealing rings 9 is inserted into the oil-duct 5 in the core 1, the other end of tube 16 being inserted into the duct of the second conductor, which may be (as shown) a second cable core 1<1> or a cable end clamp or a cable sealing end, the design of the oil flow tube depending on the nature of the second conductor. A second layer 15 of tape is wound about the core 1 slightly spaced from the winding 4 and a circumferential vice 10 is clamped about these windings. An annular groove 12 on the inner surface of the vice is connected by hole 13 to union 14 to which a vacuum pump is connected so that oil seeping between the conductor strands is removed at this point. A similar arrangement is made at the other end of the oil flow tube 16. The joining zone Z where welding takes place is thus kept oil-free. When the welding has been completed the vices 10 and 10<1> are removed and the insulation is remade. In cables having more than one conductive layer in the core the outer layers are bent back and the above method is carried out on each layer in turn.