| 摘要 |
<p>A suck-back valve in which a piston (31) and a valve body (11) are linked via a shaft portion (50), and an open/close valve (10) that carries out the open/close operation of the valve body (11) by fluid pressure is provided with a suck-back function, wherein a suck-back chamber (17) formed in a valve internal channel of the open/close valve (10) and an actuator (30) that operates the piston (31) are separated by a diaphragm (60) that is linked to and integrally operates with the shaft portion (50); the shaft portion (50) is divided into a valve-body-side shaft portion and a piston-side shaft portion, and the piston-side shaft portion is loosely fitted to the valve-body-side shaft portion, allowing for independent movement in an axial direction; and during the closing operation of the valve body (11), a two-step operation is carried out, including a valve closing operation step in which the shaft portion (50), along with the piston (31) and the diaphragm (60), moves to the fully closed position of the valve body (11), and a suck-back operation step in which the piston-side shaft portion moves with the piston (31) and the diaphragm (60) to increase the volume of the suck-back chamber (17).</p> |
