Patent ID: 9007053
Filing Date: 2015-04-14
Classification: G01N

Abstract:
1. An eddy current non-destructive inspection device comprising, at least one eddy current probe having a probe circuit including coil components, wherein the passage of a probe current through the probe circuit is effective to induce eddy currents in a test object when the probe and the test object are coupled and the probe is effective to sense the eddy currents, wherein the probe circuit has a dynamically changing probe resistance; a signal generating circuit generating at least one inspection frequency signal and a low frequency AC signal and processing the sensed eddy currents to sensed signal, wherein the at least one inspection frequency signal affects the eddy currents and the sensed signal; a signal receiving and processing circuit operable for processing the sensed signal and producing resulting signals with a signal drift caused by change in coil conditions including temperature change, wherein the processing circuit further comprising at least one compensator; a low frequency coil monitoring circuit including a detector for detecting the low frequency AC signal, a low pass filter and a resistance calculator processing the low frequency signal and producing a compensated value of the dynamic probe resistance with the signal drift annihilated, and, wherein the at least one compensator is configured to correct the resulting signals and produce corrected resulting signals based on at least one predetermined compensating operation that includes the compensated value of the dynamic probe resistance.