| 摘要 |
A normal-open metal diaphragm control valve driven by a piezoelectric element, capable of accurate and stable flow rate control even under high temperature environments and enabling adjustment of a compressive force applied to the piezoelectric element to be made without disassembling the control valve. Specifically, the control valve has a body (7) in which a valve chamber (7a') and a valve seat (7c) are formed, a metal diaphragm (8) disposed in the valve chamber (7a') and abutted to and separated from the valve seat (7c), an actuator box (10) secured to the body (7), the piezoelectric element (13) disposed in the actuator box (10) and extended downward by application of a voltage thereto to press the metal diaphragm (8) through a metal diaphragm retainer (12), a disc spring mechanism (14) for absorbing the extension of the piezoelectric element (13) when the metal diaphragm (8) abuts to the valve seat (7c) and applying a predetermined pressure to the valve seat (7c), and a preload mechanism (21) always applying an upward compressive force to the piezoelectric element (13) and capable of adjusting the compressive force applied to the piezoelectric element (13) from the outside.
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