| 摘要 |
PURPOSE:To decrease necessary turning torque as small as possible by constituting the convex streak of a seat ring so that the peripheral edge part of a valve plate contacts with the streak all together as far as possible, when the valve plate is turned. CONSTITUTION:The convex streak 11 of a seat ring 1 is most wide at the point B, and is formed narrower from the point B to the valve shaft penetration holes S1 and S2 at right and left. When the diameter of a valve plate 3 is r, the turning radius at the point A on the seat ring 1 is r costheta. As for the plane which involves the valve plate, when the valve plate is turned from opening position to closure position and contacted with the streaks of the seat ring, the angle which is formed by the valve plate and the surface perpendicular to the center shaft line of the valve in the direction of the flow of fluid is alpha, and the distance between the intersecting line formed by the surface perpendicular to the center shaft line and the convex streak and the contact point between the valve plate and the streak is l, l=r costheta.sinalpha=(r sinalpha) costheta is formed, and l forms cosine curve. |
