| 摘要 |
<p>PURPOSE:To check for the presence of non-magnetic metal, by providing an induction coil causing an AC current signal to flow through a flux gate type metal detector to detect magnetic changes due to an eddy current generated in the non-magnetic metal. CONSTITUTION:An excitation coil 3 and a detection coil 4 are wound on a ring core 2 and an induction coil 5 is wound so as to be perpendicular to the detection axis of the detection coil 4. The excitation coil 3 is excited with an electronic circuit section 6 to keep a balance between a magnetic field generated in the detection coil 4 and an external magnetic field. Moreover, a control section 14 is provided with an AC magnetic field generator 15 to apply an AC signal to the induction coil 5. Then, when any non-magnetic metal is present near the detector, an eddy current is generated in the non-magnetic metal and not only magnetic metal but also non-magnetic metal can be detected by a magnetic field produced by the eddy current.</p> |
