Study on In-Pipe Corrosion Diagnosis System -Estimation of Corrosion on Screw Parts Using a Surface SH Probe-

Abstract

Correlating to changes in society’s expectations, there is an increasing demand for the diagnosis of building equipment. Examination and diagnosis of air-conditioning pipes is an important safeguard against unexpected trouble such as pipe leakage. It is particularly important to inspect the screwed parts of pipes because their thickness is thinner than other parts due to the thread. In the past, radiography and endoscopy have been used for the inspection of screwed parts, but radiographic testing must be performed by a licensed technician, and endoscopy requires halting of plant operations. In this paper, we introduce a method for detecting and estimating the size and position of corrosion using ultrasonic testing, surface SH waves. We describe the algorithms used to estimate the corrosion size using the edge echo height, and the corrosion position using a simple numerical echo height model. And finally, we show the results of using the algorithms in experiments on pipes with artificial corrosion.