Covering conductors with polyethylene cross-linked with silane for power cables involves performing the cross-linking process on-line in the extruder barrel

摘要

Conductors are covered with polythene cross-linked with silane by means of an extruder, the cross-linking process being carried out completely or partially in the extrusion line. The catalyst can be added as a master batch with the feed (1) and the required water injected (5.1) as late as possible. Alternatively the water can be injected (5.2) first into the middle part of the barrel (2) and the catalyst injected later (5.1) near the screw tip. An independent claim is included for the corresponding equipment using high pressure pumps for the injection processes (5.1, 5.2). The extrusion head (4) is followed by a treatment zone with staged cooling in a water bath at 80 to 100 [deg]C and winding up in an atmosphere of 80 to 100% humidity and 50 to 70 [deg]C.