EDDY-CURRENT FLAW DETECTOR FOR INSPECTING LONG CONDUCTING ARTICLES Russian patent published in 2010 - IPC G01N27/90 

FIELD: physics.

SUBSTANCE: eddy-current flaw detector for inspecting long conducting articles has series-connected alternating current generator, transmission type eddy-current differential transducer (ECT), initial emf compensator, high frequency amplifier, amplitude-phase detector, low-pass filter, low frequency preamplifier, high-pass filter, controlled low frequency amplifier, threshold device, sorting control device, phase changer, direct current source and solenoid. The generator is directly connected to the second input of the compensator and to the second input of the amplitude-phase detector through the phase changer. The flaw detector also has a second differential pair of measuring windings which is shifted on the axis of the ECT by a given distance ℓ, an analogue-to-digital converter (ADC) through which output signals are measured, a program controlled microprocessor, a second measurement channel consisting of series-connected initial emf compensator, high frequency amplifier, amplitude-phase detector, low-pass filter, low-frequency preamplifier, high-pass filter, controlled low frequency amplifier, phase changer, connected between the second output of the generator and the second input of the extra amplitude-phase detector. The microprocessor is also connected through address buses and data buses to the generator, two phase changers, two high-pass filters, two controlled low frequency amplifiers, ADC, threshold device and sorting control unit.

EFFECT: increased noise immunity of the flaw detector.

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