PURPOSE: To eliminate the need of a switching valve so as to simplify the structure by providing a parallel multiply-connected reciprocating cylinder having an open forward end which is pressed and separated to and from a seat of a slurry supply port to freely open and close the supply port, and connecting a piston incorporated in the reciprocating cylinder to another advance and retreat device provided on the device frame.

CONSTITUTION: One reciprocating cylinder 14 retreated along a designated casing is advanced by an air cylinder 16 to closely adhere and be pressed to a seat 8 of a housing 7, a rotary shutter 11 is opened through its operating device 11, a hydraulic cylinder 21 starts elongating operation so that a piston 17 is advanced in the reciprocating cylinder 14 to force-feed slurry sucked and stored therein. The other reciprocating cylinder 14 is slid along a sleeve 13 by the air cylinder and retreated, and an intake port 14 is separated from the seat 8 of the housing 7 and separated. Thus, slurry can be force-fed by the reciprocal and exclusive operation of the connected reciprocating cylinder 14 without any valve.