EDDY CURRENT FLAW DETECTOR FOR CONTINUOUS MONITORING OF PIPES AND ROLLED STOCK Russian patent published in 2004 - IPC

FIELD: nondestructive continuous testing of pipes and rolled stock.

SUBSTANCE: proposed flaw detector is provided with standard signal processing circuit including AC generator, initial emf compensator, high-frequency amplifier, amplitude-phase detector whose second input is connected with generator through phase shifter, low-pass filter, low-frequency amplifier, high-pass filter, threshold unit, sorting control unit, DC source and solenoid. Proposed flaw detector is additionally provided with second pair of high-pass filter and threshold unit and EXCLUSIVE OR gate; second pair of high-pass filter and threshold unit is connected to output of low-frequency amplifier in parallel with first pair of high-pass filter and threshold unit and inputs of EXCLUSIVE OR logic circuit are connected with outputs of both pairs of high-pass filter and threshold unit; its output is connected with input of sorting control unit; cutoff frequency of high-pass filter of additional pair of high-pass filter and threshold unit lies in area of higher frequency; it is selected on the condition of avoidance of passage of signal from defect to input of EXCLUSIVE OR circuit.

EFFECT: enhanced reliability and monitoring due to increased noise immunity of detector.

1 dwg