METAL DETECTOR FOR MINERAL

摘要

PURPOSE:To perform the detection of metal pieces exactly by utilizing a change in impedance produced when mineral ore passes through a search coil for the detection of mixed metal pieces in mineral ore which are attributable to damage on conveyer belt for ores. CONSTITUTION:When passing ores with magnetism through the search coil 1 by the conveyer belt, the inductance L is increased by the magnetic permeability of ores and also the DC resistance R is increased by the iron loss of ores. The amount of energy consumed in the oscillating circuit 11 is varied with the change in the impedance of the search coil, and the change in voltage at both ends of the DC resistance RL caused thereby is taken out as an output signal through the condenser C. In this case, when the constant of the return circuit 3 is regulated and the increment and decrement of energy loss in the oscillating circuit 11 due to the changed amount of the DC resistance R are equilibrated, ore itself is not detected.