Abstract: A process of collecting and manipulating data to measure the gap between structural components of a piece of equipment or a system is disclosed and claimed. The technique uses ultrasonic zero degree longitudinal waveforms to measure the gap. The technique subtracts the average of two adjacent waveforms from the waveform being processed to remove data from reflections from the components to reveal the reflections generated by the gap.

Abstract: An apparatus for determining both the axial and angular positions of a defect in a tube wall. The apparatus includes a probe head positioned at the end of an elongated probe carrier having an imbedded orientation indicator. In the preferred embodiment, an encoder measures the angular orientation of the probe head when facing the defect relative to the angular orientation of the carrier and a photodetector and reflective strip measure the angular orientation of the carrier relative to a known orientation. A data processor uses this data to calculate the angular orientation of the probe head and the location of the tube defect.