Application of thick-walled polythene - insulation to high voltage cables

摘要

The base wire is drawn from a storage drum through a worm extruder, and after the extrusion of the thick polythene layer passes through a virtually horizontal cooling section, being finally led to a reeling up drum past one or more tensioning rollers. After leaving the extruder nozzle, at least in the cooling zone, the conductor is rotated continuously and uniformly in the same direction at between 3 and 60 rph. This rotary motion may be imparted by mounting the storage drum and the wind up reel, perhaps with tension rollers, on rotating frames. This equalises the torsional stresses inherent in the use of a worm extruder.