Process of producing a foamed plastic insulated conductor and an apparatus therefor

摘要

This invention relates to a process of producing a foamed plastic insulated conductor. This process comprises the steps of forming a foamed insulation on a conductor wire by means of a gas injecting extruder and passing said conductor wire having said foamed insulation through telescopic cooling trough means including a movable trough to be adjusted in its position relative to a head of said gas injecting extruder so as to obtain a given value of a capacitance of the foamed plastic insulated conductor in accordance with an electrical signal from a capacitance monitor to detect a value of said capacitance of the foamed plastic insulated conductor. The process of the invention is characterized by further comprising the steps of detecting the position of the movable trough adjacent to its critical or limit positions and adjusting the injection rate of the foaming gas so as to move the movable trough to the middle position of the range of movement thereof. This invention also relates to an apparatus for effecting the above-mentioned process.