GB1234397A - - Google Patents

Abstract

1,234,397. Oil-filled cables. BRITISH INSULATED CALLENDER'S CABLES Ltd. 13 Jan., 1969 [12 Jan., 1968], No. 1937/68. Heading H1A. In a method of impregnating and sheathing an oil-filled cable in which the cable core 41, Fig. 3, is drawn by a line 47 from a drying tank 43 to a sheathing press 50 through an evacuated or oil-filled tube 56, depending on whether a post- or pre-impregnation method is to be used, (1) a plug 21, of the form shown in Fig. 2, at the leading end of the core initially cooperates with an inflatable seal 45 at the mouth of the drying tank and after withdrawal allows fluid flow between the interior of the cable core and the interior of the sheath 51 formed ahead of the leading end of the cable core and (2) a vacuum plug 1, of the form shown in Fig. 1, connected in the withdrawal line 47 seals the end of the sheath and can be used in co-operation with a plug at the trailing end of the cable core to permit completion of the impregnating and vacuum sheathing operations and cutting and capping of the leading end of the cable core without allowing air access into the sheathed cable core. The vacuum plug 1, Fig. 1, is similar to that described in Specification 1,192,588 having a temporary seal, e.g. a readily puncturable diaphragm 4, a through bore 3 and a soft rubber bung 6, but provided with an end cap 5 having an eye bolt for attachment to the withdrawal line. The cable sheath is sealed to the vacuum plug by deformation of the sheath onto the rubber bung 6. The cable core end plug 21, Fig. 3, has 0-ring seals 26, a ferrule portion 23 for sweating to the cable conductor and a blind bore 24 for effecting connection to the withdrawal line or to an electrical terminal, e.g. when an electric conductor is attached for electrically heating the cable core to dry it. Reference, has been directed by the Comptroller to Specification 1,059,951.