Examination of Thickness Measurement Method for Hot Spring Scale inside Steel Pipes using Electromagnetic Force Vibration

At geothermal power plants has a problem that the large-diameter steel pipe is blocked by solid material of hot spring water's components, called for “hot spring scale”. Therefore, it is necessary to develop a method for measuring the thickness of hot spring scale from the outside of large-diameter steel pipe. In this paper, we investigated a non-contact inspection method that uses electromagnetic force vibration to measure the thickness of hot spring scale from the outside of a steel pipe. In addition, the proposed inspection method was evaluated by comparing electromagnetic force and displacement analysis using the 3-D finite element method (FEM), and verification experiments.