Test verification of an extensometer for deformation measurement of high temperature straight pipes

In order to measure deformations of high temperature pipes, an extensometer is designed and verified by experiments. Firstly, the structure and working principle of the extensometer are described. Then experiments both in the laboratory and on site are carried out to prove stability and accuracy of the extensometer. Results from experiments are compared with the calibrating values, and they are in good agreement. The operating condition of the main steam pipe is evaluated by the on-site test. Conclusions can be drawn that the designed extensometer has reliable stability and high accuracy and can be used for measuring deformations of high temperature pipes in power plants.