Parameter Optimization Of Pulsed Eddy Current Testing For Pipeline Under Insulation

Pipe with insulation has been widely used in the oil, chemical and powerindustries, and its wall thinning is a threat to the reliability and safety of theequipment operation. The conventional detection technique needs to remove theinsulation, which is of low efficiency and high cost. Pulsed eddy current testing ofpipe with insulation has advantages of no need to remove the insulation layer, nodowntime, low cost, high performance, safety and low labor.This paper studied the influence of different testing parameters on pulsed eddycurrent testing of pipe with insulation which was then used to optimize test parametersand methods.Finite element method was used to build simulation model to analyze themagnetic field in pipe and protective layer of aluminum and detection sensitivity ofdifferent location of the receiving sensor. Appropriate location of receiving coil wasdetermined and used in the probe design.Influence of different receiving sensor on testing was studied. Different turns ofthe receiving coil were used for experiments and compare their detection sensitivityby using stake-voltage graph and detection sensitivity curve. Experiments using TMRprobes with different insulation thickness were performed, and influence of TMRprobe orientation was investigated. Finally coil-receiving probe and TMR probe arecompared.Influence of different excitation current, different excitation frequencies underdifferent insulation thickness and protection layer was studied and optimum testingparameters were determined by analyzed by analyzing stake-voltage graph anddetection sensitivity curves.Finally, the conclusions are given and suggestions for the future work areproposed.