摘要 |
Method and apparatus for applying a layer of insulation around an electrical cable core in which the contaminant size is not greater than about 200 microns. Unplasticized insulation material, such as polyethylene, is supplied to an extruder which forces the material through a filter which prevents the passage of contaminants having a size greater than about 200 microns and in which there is a pressure drop. The filtered material is delivered to a pump which increases the pressure thereon and forces it through a static mixer at the output of which the filtered material is delivered to the cross-head of extrusion apparatus which applies the filtered material to the cable core as it is advanced longitudinally. If the insulating material is to be cross-linked by a cross-linking agent, the agent is injected into the filtered material between the pump and the mixer.
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