| 摘要 |
PROBLEM TO BE SOLVED: To provide a small flaw sensor suitable for diagnosing a water pipe and a device for diagnosing the degree of decrepitude of a water pipe. SOLUTION: The flaw sensor 20 for a water pipe includes an exciting coil unit 21 with an excitation coil 211 stored inside a metal casing 212, and a receiving coil unit 22, with a first 221 and a second receiving coil unit 222 stored in a metal casing 223. The small sensor is produced, by forming a pseudo-metallic conduit with the exciting coil 211 stored inside the metal casing 212 and the wall thickness portion 11 of a water pipe 10. Separately from the first receiving coil 221 used for measurement of wall thickness, the second receiving coil 222 with the straight axis is provided, and the estimation the accuracy of wall thickness is improved, by correcting the fluctuations in the phase difference due to the magnetic characteristics of a water pipe by using a signal received by the receiving coil 222. COPYRIGHT: (C)2011,JPO&INPIT
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