| 摘要 |
PROBLEM TO BE SOLVED: To reduce a cavitation generated in a valve contracted flow part, and to suppress noises and improve the controllability by suppressing the cavitation. SOLUTION: This eccentric butterfly valve, in which a seal face between the circumferential face of a valve element 23 and a body 21 inside face does not pass the center of a valve rod 24 in being fully closed, is characterized that the outside diameter of the valve element 23 and the body inside diameterϕD of the valve seat 22 are set to 0.8 time or less of the pipe inside diameterϕD so as to suppress the noise and the cavitation generated from the valve element 23; the body inside diameter 21a in an orifice side right after the valve seat is enlarged to the same dimension of the pipe inside diameterϕD; and the body inside diameter in the nozzle side has a structure 21b formed along the outside diameter of the rotating valve element 23 and is enlarged to the same dimension with the pipe inside diameterϕD on the way to the secondary side flange face 25 so as to improve the controllability at the small opening.
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