To secure stable discharge and raise reliability by keeping either one of a first pressure and a second pressure as a reference pressure and controlling a first controlling means and a second controlling means in such a manner as to keep another of the two pressures at a specified pressure in comparison with the reference pressure in order to control discharge through an outlet.
A pressure P1, which is to be realized in an (A) section (consisting of a piezo-valve 31 and a pressure transmitter 32), is inputted to a controller 40 in advance and an electric signal is inputted to the piezo-valve 31 according to the pressure P1. On the other hand, the pressure transmitter 32 transmits a detected pressure value as an electric signal to the controller 40 in real time. If the pressure detected by the transmitter 32 is higher than the P1, ratio of valve opening of the piezo-valve 31 is reduced, and on the contrary, if the pressure detected by the transmitter 32 is lower than P1, then the ratio of valve opening of the piezo-valve 32 is increased to keep pressure in the (A) section at P1.
SAGAWA USHIO
MIURA MASAYOSHI
IWAZAWA TOSHIYUKI
NAKA HIROYUKI
