Study on the scale thickness measurement technique in the steel pipe for Geothermal power station

Until now, authors thought it required extending the life of steel tubes for piping in order to use the geothermal power station in the good state over a long period of time. It has dealt with development of the deterioration-diagnosis technology of the geothermal power station steel tubes for the piping by the simple nondestructive inspection technique using an impact (shock) sensor for the purpose of this preventive maintenance. As a result, it succeeded in catching change of the stream in the steel pipe by change of the thickness of the mineral-rich sediment (the following, scale) adhering to the piping inner wall in steel tubes for piping by an impact sensor. So, in this paper, it measured about stream change using the ultrasonic sensor considered to be suitable for the metal deterioration diagnosis of steel tubes for piping rather than the impact sensor. As a result, since the increase in an ultrasonic wave signal with scale thickness and correlativity was checked, it reports.