Thickness measuring of electroconductive pipe walls using the dual-frequency eddy-current method

13th European Workshop on Advanced Control and Diagnosis

Yakimov, Evgeny^1 ; Galtseva, Olga^1 ; Ustyugov, Daniil^1

Tomsk Polytechnic University, Institute of Non-Destructive Testing, Tomsk

634050, Russia^1

关键词: Correction algorithms;    Digital signal processing algorithms;    Dual-frequency methods;    Eddy current transducers;    Electrical conductivity;    High frequency signals;    Impact of changes;    Piecewise linear approximations;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/783/1/012061/pdf
DOI  :  10.1088/1742-6596/783/1/012061

来源: IOP

【 摘 要 】

The paper describes a dual-frequency method for reducing the impact of changes in the gap size between the eddy-current transducer and the pipe, as well as the pipe electrical conductivity on the eddy-current thickness gauge readings. A block-diagram of the dual-frequency eddy-current thickness gauge is proposed for light-alloy drill pipes. The amplitude and signal phase dependencies on the wall thickness in the range from 6 to 17 mm and the gap in the range from 0 to 13.5 mm were studied, the results are presented. The digital signal processing algorithms based on the piecewise-linear approximation of low-frequency and high-frequency signal phase dependencies on the wall thickness are proposed. It is shown that the proposed correction algorithms can reduce the error caused by variations of electrical conductivity and the gap between the transducer and the pipe.