Continuous coating applied to insulation on electric cable - where soot or graphite powder is rolled onto insulation to form compacted electrically-conducting layer used for cable screening

摘要

Powdered soot or graphite is fed continuously onto the insulation on an electric cable. The powder is then rolled so that it is compacted and/or smoothed to form a continuous conducting coating on the insulation. The powdered soot or graphite pref. contains a binder to assist its consolidation round the insulation. The pref. coating appts. includes at least two rolls located in a ring cage which is rotated round the cable, so the rolls rotate on the powder coating. Each roll may also be driven. The compacting rolls may be followed by a set of smoothing rolls. The surface of the rolls pref. consists of steel or a felt. A simple and reliable method is provided for forming a conducting carbon layer in a cable; this layer is used esp. for screening.