| 摘要 |
<P>PROBLEM TO BE SOLVED: To increase the life of a valve box seal ring while reducing operation torque and holding a water shutoff property when the valve box seal ring is pressed against disk tail parts. <P>SOLUTION: A butterfly valve having a water filling function includes the valve box seal ring 3 installed on the inner peripheral surface of a valve box, a valve element for opening and closing a flow path inside the valve box, and the pair of disk tail parts 11a, 11b formed on the outer periphery of the valve element on the rear surface side in the valve opening direction. The pair of disk tail parts 11a, 11b have outer peripheral surfaces which are pressed against the valve box seal ring 3 and curved spherically when the valve element is opened very slightly. A water passage hole 12 whose one end is opened to the outer peripheral surface and whose other end is opened to the rear surface side of the valve element is formed in at least one of the disk tail parts 11. A recess 13 is provided to at least one outer peripheral surface of the disk tail parts 11a, 11b. <P>COPYRIGHT: (C)2012,JPO&INPIT |
