| 摘要 |
PROBLEM TO BE SOLVED: To provide a circular pipe cutting method for cutting a circular pipe by a simple configuration. SOLUTION: In this method used instead of a conventional method for cutting a circular pipe, an injection nozzle being rotatable while jetting high pressure water for cutting a wall of the circular pipe immersed in a liquid and changing a rotation angle gradually centered on a virtual central axis, and a detection apparatus for detecting underwater sound at a specific position in the liquid and outputting signal data, are prepared to rotate the injection nozzle jetting high pressure water so as to change the rotation angle into one direction of rotation in order to cut the circular pipe. The signal data is recorded in response to the rotation angle. An improper cutting rotation angle being the rotation angle corresponding to an improper cutting section being the section where the wall of the circular pipe is not cut is specified and the injection nozzle jetting the high pressure water in the radial direction of the circular pipe is rotated to let the rotation angle agree with the improper cutting rotation angle, based on the level of specific frequency band of the signal data. COPYRIGHT: (C)2009,JPO&INPIT
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