PURPOSE: To hold always a proper amount of polishing stones for same efficiency polishing even in a long time polishing operation by providing a means for detecting an amount of screened polishing stones and a supply means for replenishing deficient polishing stones on the basis of the detected values.
CONSTITUTION: When an amount of screened polishing stones 12 is reduced, a float (detecting means) 8 is lowered as shown by the arrow 16, so that a switch valve 11 is also lowered in the same direction through a plate body 10. When the switch valve is lowered lower than a fixed position, a portion of a supply tube 7 is opened and the polishing stones 12 in a hopper 6 are, as shown by the arrow 17, supplied and replenished from said opened portion into a connecting pipe 3 connected to the downstream side of a selecting screen 2 in a barrel tank 1. Next, as the amount of polishing stones is increased, the float 8 is elevated and accompanied by the lift of switch valve 11 so that the supply of polishing stones 12 is reduced. Thus, by controllably opening and closing the switch valve 11 is held always a proper amount of polishing stones so that polishing can be performed with the same efficiency.
SEO YOICHI
INUKAI YUJI
