METHOD AND DEVICE FOR MONITORING AND DETECTING THE COATING DEFECTS OF AN UNDERGROUND OR UNDERWATER PIPELINE

摘要

The invention relates to a method and device for monitoring and detecting coating defects in a defined section of a coated underground or underwater pipeline which is provided with a monitoring unit fixedly mounted by sections and at the ends of the respective section. The inventive method consists in applying an alternating current signal in a clock manner on the pipeline, in recording the waveform thereof in the monitoring units of the two ends of the respective monitorable section for determining the distance-dependent damping rate, in converting a time-dependent signal into a frequency-dependent signal, in determining the amplitude of a frequency corresponding to the alternating current signal frequency, in determining the damping rate of the frequency amplitudes in the pipeline monitorable section and in comparing with predetermined comparison values in the monitoring units of the two ends.