JPS55107945A - Water content control device for batcher plant - Google Patents

Abstract

PURPOSE: To enable control of the water content of material provided between needle-like electrodes of measuring electrodes under a hopper by measuring the electrostatic capacity of the material to obtain the water content and simply measuring the water content of the material before completing the measurement during the measuring step.

CONSTITUTION: When material is fed to a weighing hopper 4 and the state that the water content of the material may be measured is detected by a level switch 11, measuring electrodes 7 are urged onto the material 9. At this time the resonance of a resonance circuit 19 is displaced by the electrostatic capacity of the material 9 from the electrodes 7. This displacement of the resonance is detected by a rectifier circuit 20, which then applies the detection output through a feedback circuit 21 to variable capacity diodes VC1, VC2 to again set the resonance circuit 19 to resonant state. Then, an electrostatic capacity-to-voltage converter circuit 22 converts the electrostatic capacity change to a voltage corresponding to the capacity change. A differential amplifier 23 further produces the difference output showing the water content of the material 9 with the output voltage when the measuring electrodes 7 are not urged onto the material as a standard voltage, thereby measuring the water content simply.

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