MUTUAL INDUCTION TYPE THROUGH TEST COIL AND EDDY CURRENT FLAW DETECTOR

摘要

PROBLEM TO BE SOLVED: To facilitate the sure detection of a fine flaw covered with pseudo barrier noise caused in material handling such as carrying which was assumed to be impossible to remove in the past, and simplify the structure of the hardware of an eddy current flaw detector to reduce the cost of the device. ;SOLUTION: This mutual induction type through test coil has exciting coils 20, 21 installed around a through-hole so as to pass a material 1 to be inspected for an eddy current flaw detector, and detection coils 31, 32 wound around the through-hole so as to be laid along the inside surfaces of the exciting coils 20, 21. The detection coils 31, 32 are formed so that both end parts and the center parts can be connected to an external circuit, and the winding width W of the exciting coils 20, 21 and the detection coils 31, 32 is set to a prescribed ratio having the diameter D of the exciting coils 20, 21 as coefficient, and the vertical component force reducing range of the excited magnetic flux by the exciting coils 20, 21 is set to be equal to or more than the magnetic flux sensitive range of the detection coils 31, 32.;COPYRIGHT: (C)1998,JPO