SENSOR AND APPARATUS FOR FLAW DETECTION OF METAL PIPE

摘要

PROBLEM TO BE SOLVED: To obtain a sensor and an apparatus which are not affected by an external noise, which are lightweight and which eliminate an error by amplifying received signals by a plurality of receiving coils to be at a prescribed level so as to be converted into digital signals at respective channels corresponding to the respectively receiving coils and sending out serially the received signals as the digital signals by a parallel/serial converter in a time-sharing manner in the order of the channels. SOLUTION: A receiving coil group 9 which is arranged and installed at a remote-field eddy current sensor 7 is constituted of a plurality of receiving coils RC1 to RCn , the coils receive remote-field eddy currents which are prorated inside the thick wall of a metal pipe 6 and which are generated by an exciting coil 8, and they output weal AC signals at several to several tens ofμV. Received signals which are output are connected to corresponding input terminals which are arranged and installed inside a parallel/serial conversion unit 10 by using (n) pairs of transmission cables. The signals are converted into serial digital signals by a parallel/serial conversion module PS inside the conversion unit 10, and they are connected to a remote-field metal pipe-flaw detection apparatus via a cable 11 for signal transmission.