Pipeline testing system - has external alternating current coil and internal magnetic flux sensor

摘要

A device to produce a signal outside a pipe line and determine a signal within a pipeline, the existence of which is shown by the external signal produced, has an alternating current coil (13) attached outside the pipeline (11) such that the pipeline does not pass through the core of the spool but penetrates at least part of the imaginary surface projected parallel to the alternating current coil. An alternating current source (15) is provided for the coil (13), by means of which eddy currents of induced magnetic flux are produced in the pipeline (11). A detector sensitive to magnetic flux (16) is mounted within the pipeline (11) to measure the magnetic flux produced.