Continuous qualitative inspection of conductor insulating sheath - using capacitance measuring gauge immersed in cooling water surrounding extruded cable

摘要

A procedure is described for continuous, qualitative inspection of the insulating envelope of a conductor insulated by a polyolefine extrusion. The conductor is made to pass into a capacitance measuring gauge immersed in the water of the conductor's cooling bath, and the output signal from the gauge is treated so that an alarm signal is produced when thickness faults are detected on short lengths of conductor. The gauge is annular and the output current is positive or negative depending on whether the measured value of the capacitance is greater than or less than a nominal value.