| 摘要 |
PROBLEM TO BE SOLVED: To always properly perform pressure feedback control even if a set value of a working pressure differs according to a change in a type of a chemical or the like, and as a result to accurately control the flow rate of the discharged chemical. SOLUTION: A pump 11 has a pump chamber 13 and a working chamber 14 partitioned by a diaphragm 12 made of a flexible film, for sucking and discharging the chemical depending on a change in pressure in the working chamber 14. An electro-pneumatic regulator 32 supplies working air to the working chamber 14. In addition, this system is equipped with a plurality of pressure sensors 51 and 63 different in a pressure detection range as pressure detecting means for detecting the pressure of the working air. A controller 40 selectively employs either of detection results of the plurality of sensors 51 and 63 depending on a set pressure value of the working air which is specified each time, for performing the pressure feedback control. COPYRIGHT: (C)2007,JPO&INPIT
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