| 摘要 |
PROBLEM TO BE SOLVED: To provide a method and an apparatus for monitoring cracks whereby cracks inside a piping can be correctly and simply monitored even under a high temperature environment. SOLUTION: In the apparatus and method are carried out an electrode-setting process, a potential difference-measuring process, a potential difference-correcting process and a crack length-calculating process. In the electrode-setting process, a pair of heatproof current input/output electrodes 12a and 12b are mounted to an outer circumferential face of an arranged pipe 100 to hold a crack 100b of the pipe 100 therebetween, while two pairs of heatproof crack potential difference-measuring electrodes 12c-12f are set to the outer circumferential face of the pipe 100 to be positioned between the current input/output electrodes 12a and 12b. In the potential difference-measuring process, an a.c. is sent between the electrodes 12a and 12b and a potential difference of the crack potential difference-measuring electrodes 12c-12f is measured. The potential difference of the crack potential difference-measuring electrodes 12c-12f is corrected in the potential difference-correcting process. A length of the crack 100b is obtained in the crack length-calculating process on the basis of the potential difference obtained in the crack potential difference-correcting process.
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