| 摘要 |
<p>A mutual-induction insertion probe free from any noise effect. The mutual-induction insertion probe (11) detects any flaw (5) in an object (a pipe (1)) by eddy current. The mutual-induction insertion probe (11) comprises an excitation coil (13) having two coils (13a) and (13b) for exciting the object (the pipe (1)) facing each other with a predetermined spacing and a detection coil (15) which is coiled in a direction orthogonal to the excitation coil (13). Eddy currents of the same value in the opposite directions to each other are generated in the object (the pipe (1)) by the coils (13a) and (13b). If there is no flaw in the pipe (1), no electromotive force is generated in the detection coil (15). If there is any flaw in the pipe (1), the eddy current flows parallel to the plane of the detection coil (15) at the flaw, and the electromotive force is generated in the detection coil.</p> |
