GB426354A - - Google Patents

Abstract

426,354. Cables. CALLENDER'S CABLE & CONSTRUCTION CO., Ltd., and HUNTER, P. V., Hamilton House, Victoria Embankment, London. Oct. 10, 1933, No. 27901. [Class 36] A two-stage process for effecting the impregnation of the dielectric of a paper-insulated conductor comprises impregnating the previously dried laminated dielectric body of paper surrounding the conductor with a mobile insulating oil, removing from the insulated conductor, under conditions that do not result in evaporation of the oil absorbed by the paper, surplus oil unabsorbed by the paper, and subsequently impregnating the laminated dielectric with a relatively viscous insulating oil or compound. The conductor insulation is first dried and inserted in a vessel which is thereafter evacuated and into which, for example, transformer oil at 245 to 250‹ F. is drawn ; the impregnation process may be assisted by subjecting the oil to pressure or by evacuating the conductor from the interior or both. The vessel is then drained or the conductor removed and drained, after which the conductor is again subjected to vacuum in the vessel into which a more viscous fluid is then drawn ; for such impregnation, an oil of the same base, containing, if desired, rosin, may be employed at 245 to 250‹ F. ; pressure or evacuation or both may be applied as before. After cooling, the conductor is withdrawn and sheathed, for example, with lead. The dielectric may be dried by heat and evacuation prior to each impregnation treatment. The process may be applied to single or multi-core cables.