Evaluation of Magnetostrictive Transducers for Guided Wave Monitoring of Pressurized Pipe at 200 °C

Many piping networks in processing plants, such as refineries, chemical plants, and electric power generation plants, are operated at elevated temperatures (≥250 °F or 121 °C). Failure of these insulated high temperature pipes can cause a major disruption of plant operation. In addition to inspection during the regular plant shutdowns, processing industries are looking for ways to inspect and monitor these pipelines on-line to ensure safe operation of the plants. Permanent monitoring of high temperature structures would require addressing the following technical problems: supporting the sensor functionality at high temperatures, ensuring the probe durability, and maintaining good coupling of the probe to the structure. In this work, a probe utilizing magnetostrictive transduction was tested on a mockup at 200 °C and produced a steady high amplitude signal over a period of 270 days. Probe performance parameters such as signal to noise ratio, data reproducibility, and sensitivity to anomalies are discussed.