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Apparatus for extruding a first layer of a semi-conductive plastic material around the conductor of an electric power cable and for extruding a second layer of plastic insulating material around the first layer as the conductor is advanced in which the extruder for the insulating material includes a

Apparatus for extruding a first layer of a semi-conductive plastic material around the conductor of an electric power cable and for extruding a second layer of plastic insulating material around the first layer as the conductor is advanced in which the extruder for the insulating material includes an extrusion head which comprises a body with a passageway therethrough for the passage of the conductor through the body and having at least one channel therein extending from the exterior thereof to adjacent one end of the passageway for supplying the insulated material around the conductor. An extrusion tip or tubular guide is disposed in the passageway for guiding said conductor and extends across part of the channel for contacting material exiting from the channel. The guide comprises a ceramic tube with a polished inner surface forming the innermost surface of the guide.

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An extrusion head for the extrusion of a plastic material around a conductor of an electric cable, said head having a body with a passageway therethrough for the passage of said conductor through said body, said body having at least one channel therein extending from the exterior thereof to adjacent

An extrusion head for the extrusion of a plastic material around a conductor of an electric cable, said head having a body with a passageway therethrough for the passage of said conductor through said body, said body having at least one channel therein extending from the exterior thereof to adjacent one end of said passageway for supplying said plastic material around said conductor, and a separate tubular guide body disposed in said passageway, having an open inner tubular bore portion for the passage of said conductor through said tubular guide body and said tubular guide having an external portion extending across part of said channel for contacting said plastic material exiting from said channel, said guide body comprising a ceramic tube with a smooth inner surface of ceramic forming said bore portion of said guide body and the ceramic of said guide body having a thermal conductivity at 100°C. of less than 0.1 cal/(sec.cm.°C.)