To provide a butterfly valve with a flooding function for passing a constant flow of water at small opening, and also to reduce pressure loss at full valve element opening of the valve.
Two valve element pieces 9a and 9b of a valve element 7 have disk tail parts 10a and 10b. Both disk tail parts 10a and 10b are positioned on a back side of the valve element 6 with respect to a rotation direction of an unstopping operation, and are provided with a spherical outer circumference in sliding contact with a valve casing seal ring 3 arranged in a valve casing 2. The disk tail parts 10a and 10b have a water passage hole 14. In a full closing position S, a circumferential edge of the valve element 6 is in sliding contact with the valve casing seal ring 3. A full opening position O is set in a position to which the valve element 6 is rotated through 90°+α°/2 in an unstopping direction from the full closing position S, where α° is an extension angle of the valve element pieces 9a and 9b and the disk tail parts 10a and 10b on a rotation axis 5 measured in a valve element rotation direction.
| WO/2019/169075 | MANUAL OVERRIDE SYSTEM FOR MAGNETICALLY ACTUATED VALVES |
| WO/2020/077332 | SMART VALVE WITH INTEGRATED ELECTRONICS |
SATO KEIICHI
KITAMURA MASAAKI
HOURAI AKINOBU
KUBOTA KK
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