Patent ID: 8228078
Filing Date: 2012-07-24
Classification: C23F,F16L,G01N

Abstract:
1. A method for monitoring and detecting coating defects in a defined section of an underground or underwater coated pipe line, wherein the pipe line is provided section-wise at the ends of the particular section with a fixedly installed monitoring unit and comprising: application of an AC current signal at a clock cycle onto the pipe line, whose fixedly predetermined and stable frequency, taking into consideration the tolerance, is distinct in comparison to the frequencies measured within the scope of the monitoring of possible external interference signals, acquisition of the wave form of the AC current signal in the two terminal monitoring units of the particular section to be monitored for the determination of the distance-dependent attenuation level as a function of the distance of the signal from the site of the impression with this signal, conversion of the time-dependent signal into a frequency-dependent signal, determination of the frequency amplitudes corresponding to the frequency of the AC current signal, determination of the level of attenuation of the frequency amplitudes within the pipe line section to be monitored and comparison with comparison values previously determined in the two terminal monitoring units.