Heat exchanger tube state detecting apparatus for e.g. crack identification, has two coils disposed at circumferential location in probe bodies, where signals are synchronized on direction by finding velocity of movement of bodies

摘要

The apparatus has defect and geometric transition detecting eddy current coils (1, 7) detecting a defect such as pit, and a geometric transition such as dent, of a heat exchanger tube, respectively. The coils are disposed at a circumferential location in related cylindrical probe bodies (3, 5, 6) and are installed to a certain distance in a lengthwise direction of the bodies. A time difference occurs between eddy current signals collected from the related coils such that the signals are synchronized on the direction by computing velocity of movement of the bodies. An independent claim is also included for a method of detecting a state of a heat exchanger tube.