| 摘要 |
<p>A valve body (11) is formed by separably superimposing, one upon the other, a large diameter first valve body portion (11a) in contact with a first valve seat portion (7a) formed on the inlet side of a valve hole (8), and small diameter second valve body portion (11b) in contact with a second valve seat portion (7b) formed on the outlet side of the valve hole (8). The first valve body portion (11a) is formed of an elastic material, and at least the portion of the second valve body portion (11b) other than the portion in contact with the second valve seat portion (7b) is formed of a rigid material. At the center of the first valve body portion (11a) , there is formed a through-hole (18) through which the valve operating shaft (10) is passed. The forward end of the valve operating shaft (10) passed through the through-hole (18) is connected to the second valve body portion (11b). Between the firstvalvebodyportion (11a) and the valve operating shaft (10), a first valve body portion moving means (19) is provided, which is adapted to effect mutual engagement at the time of valve opening to move the central portion of the first valve body portion (11a) away from the second valve body portion (11b). At the connecting portion of the forward end of the valve operating shaft (10) and the second valve body portion (11b), a second valve body portion valve opening operation delaying means (20) is provided, which delays, at the time of valve opening, the valve opening operation of the second valve body portion (11b), and gives priority to the operation of moving the first valve body portion (11a) by the first valve body portion moving means (19). As a result, in the valve body (11), composed of the first valve body portion (11a) and the second valve body portion (11b), even if the outer diameter of the first valve body portion (11a) on the fluid inlet side on which the fluid pressure acts is large, it is possible to open the valve with a smaller force than in the prior art.</p> |
