PURPOSE: To perform automatic control of the slurry concentration simply and reliably by comparing the electricity quantity indicating the weight of a slurry storage tank and the electricity quantity of the preset slurry concentration, opening a magnet valve when the former is thinner than the preset value, and rotating a motor.
CONSTITUTION: When a comparison circuit C3 is activated by the operation of a timer T, the measured slurry concentration and the preset slurry concentration in voltage respectively are compared, and if the measured concentrationis thinner than the preset concentration, a signal is sent from the comparison circuit C3 to a magnet valve V2 having a motor M, a magnet valve V1. amd a delay relay R, the motor M is rotated for a fixed time to feed a new abrasive to a slurry tank 2, the slurry in a slurry hopper a1 is fed into the slurry tank 2 as the magnet valve V1 is opened, thereby new grinding grains are further added to the slurry and stirred to obtain dense slurry. When the concentration becomes within the tolerance, the motor M is stopped by a signal from the comparison circuit C3, and valves V1, V2 are closed.
WATANABE MITSURU
SUZUKI HIDEMASA
