PROCESS OF MAGNETIC FIELD TESTING AND DEVICE TO IMPLEMENT IT Russian patent published in 1999 - IPC

FIELD: nondestructive inspection of thin-walled ferromagnetic objects, predominantly pipe-lines. SUBSTANCE: device is manufactured in the form of flaw detector-tool placed inside pipe. Walls of object are magnetized to state of saturation of magnetization system having circular pole pieces. Surface of object is scanned with use of multilink ring magnetosensitive converter placed between poles of magnetization system. Base of flaw detector has air-tight compartment housing information signal former. Differential amplifiers of it amplify signals of converter and send them into multichannel register. Reference signal formed by summing of signals of all sensitive elements of converter and multiplied by safety factor exceeding one is supplied to first inputs of differential amplifiers. EFFECT: effective protection of magnetic flaw detectors-tools against interference caused by changes of their movement velocity and thickness of walls of tested object. 5 cl, 11 dwg