| 摘要 |
PROBLEM TO BE SOLVED: To provide a control valve, having simple structure, performing accurate opening and closing operation, and having excellent sealing ability in the closed state of the valve. SOLUTION: This control valve includes: an elevating body 4 moved and stopped in a required upper or lower position by normal rotation and reverse rotation of a driving shaft 3a of a step motor 3 having an encoder 15; and a diaphragm valve, the opening of which is controlled by the upper or lower position of the elevating body, wherein in closing the diaphragm valve, a driving pulse supplied to the step motor is supplied to excess until the loss of synchronism is detected in the encoder. A peripheral projection 13 substantially concentric with a valve hole is provided in the periphery of the valve hole 12 in a valve seat 9 of the diaphragm valve, and a peripheral groove 11 engaged with the peripheral projection is formed in the lower surface of the valve body 8 projected downward form the center of the diaphragm and formed of elastic material, whereby when the diaphragm valve is closed, the peripheral groove is fitted to the peripheral projection to improve the sealing ability in the closed state of the valve. COPYRIGHT: (C)2005,JPO&NCIPI
|
