炭鉱における不発雷管 (流管) 検出について

抄録

In the most recent we have been interested in keep away from an explosion accident by the misfired detonstors. In this paper we shall report on the electronic metal detection.
The metal detector is build around some form of mutual-inductance bridge employing a symmetrical coil arrangement which is bed by a suitable oscillator. The presence of a metallic particle in the A. C. electro-magnetic field which links the coils disturbs the original field pattern for which the bridge was balanced. The resulting bridge unbalance current is amplified and made to operate a warning or rejection device.