GB458254A - Improvements in or relating to the manufacture of electric cables or other insulated conductors having mineral powder insulation - Google Patents

Abstract

458,254. Coating electric conductors by extrusion machines. CONDUCTEUR ELECTRIQUE BLINDE INCOMBUSTIBLE, 54, Avenue Marceau, Paris. March 12, 1935, No. 32124/36. Convention date, March 12, 1934. Divided out of 458,257, [Group XXXVI]. [Class 87 (ii)] In making electric cables or other insulated conductors having insulation consisting of a mineral powder such as magnesia or other metallic oxide or salt or mixture thereof, the insulating material is extruded in paste form through a die 3 around one or more conductors 4 and the insulated conductor is surrounded with a permeable covering 9 formed as by winding or braiding and is enclosed in a metal sheathing. The paste may be forced from a container 1 by fluid under pressure admitted to a tank 6 by a duct 7. Liquid 8 may be interposed between the paste and the pressure fluid. The conductor 4 may be fed from a reel 5 through the container 1 and die 3. On emerging from the die, the cable may pass through a tubular electric heater 10 which dries it sufficiently for passing to a braiding machine where the cover 9 is applied. Further heating may be applied to dry the insulation and the conductor may then be enclosed in the outer sheath. The paste may be extruded by a plunger or other mechanical means. The paste may be formed by wetting the insulating powder, such as powdered magnesia or alumina, with a liquid containing in suspension one or more substances, such as a silicate or boric acid, adapted to make the powder more cohesive.