| 摘要 |
PROBLEM TO BE SOLVED: To provide a ball valve for retaining a capacity coefficient substantially identical to that of a turbulent state even in a non-turbulent state.SOLUTION: The most downstream end of a wall surface 71a' of a flow characteristic window 71 is made into the narrowest diameter part of a passage 3 in a valve body 4 and a through flow passage 7 of a ball valve element 5. The wall face 71a' of a passage from that narrowest diameter part to the most upstream end of the wall face 71a' of the flow characteristic window 71 is a taper face inclined toward the narrowest diameter part, and the passage is abruptly expanded from the narrowest diameter part of that flow characteristic window 71 into the through flow passage 7.SELECTED DRAWING: Figure 1 |
