| 摘要 |
PURPOSE:To prevent occurrence of erosion and to improve durability by arranging a plurality of notches for dispersing a fluid on the edge portion on the preceding side with the valve closing operation of a valve element in the direction of the center of a rotary shaft of the valve element. CONSTITUTION:As a valve element 4 is turned to the valve closing side to be put in a vary small opening state, a fluid in a valve casing 2 is dispersed to flow in the direction of the center of a rotary shaft of the valve element 4 by a plurality of notches 7, so that flow energy is dispersed to restrain the occurrence of cavitation. The valve element 4 has an edge portion 4A on the preceding side with the valve closing operation thereof, in which a plurality of notches 7 for dispersing a fluid are arranged in the direction of the center of the rotary shaft of the valve element 4. The shape of each notch 7 in the longitudinal section is tapered toward the downstream side to prevent separation of flow at each inlet portion of the notches 7.
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