Gauging and Imaging of Pipes Using a Water-Immersible Ultrasonic Instrumentation System

The purpose of this research work is to establish the functionality of the novel ultrasonic non-destructive inspection system and accurate gauging of pipes and to locate and visualize flaws in the form of B-scan cross-sectional view (front-view) of the pipe under test. This paper presents a custom-made perspex inspection head assembly integrated with a stand-alone, Li-ion battery-powered and IP67-grade water-immersible ultrasonic instrumentation and gauging system, which enables an efficient assessment of the condition and health of pipes in stringent environments. Extensive inspection was carried out on six samples of 12 in. inner diameter (ID) type carbon steel (CS) pipes with length of 500 mm and having machined wall thickness to simulate loss of wall thicknesses from 10% over a length 150 mm of pipe, using 5 MHz spherically focused transducers. Further inspection were carried out on a 12 in. CS pipe with four notches and four flat bottom holes (FBHs) machined on the outer diameter (OD) side. Identical flaws were also machined onto 12 in. CS pipe of total length 700 mm containing water inside the pipe in flowing condition with water flowrate of 100 liters per minute (LPM). The test results demonstrate the effectiveness of the developed IP67-grade water-immersible ultrasonic pipe inspection and gauging instrumentation system for assessing the condition and health of long-length carbon steel pipes operating in harsh environments.