To perform smooth jumping up and down of an oscillation pipe during washing the oscillation pipe.

An oscillation pipe 6 is oscillatorily contained in a hopper 1 having two suction delivery ports 2 formed in the lower part of a front wall 1a and laterally juxtaposed with each other. The tip part of a coupling shaft 8 having a base end coupled to the oscillation pipe 6 is positioned at the outside of the hopper 1 in such a state to extend through the hopper front wall 1a. During washing of the oscillation pipe 6, the oscillation pipe 6 is jumped up in such a state to be matched with an opening 23 formed in the upper part of the hopper front wall 1a. A shaft push cylinder 32 to push rearward the oscillation pipe 6 is coupled to and installed at the tip of the coupling shaft 8.