| 摘要 |
1319332 Valves ANDREWS INDUSTRIES Inc 43446/70 [17 Sept 1969] Heading F2V A butterfly valve has a pressure-balanced closure plate whose entire periphery is spaced from the seat surface in the open condition, and the entire periphery is brought into compressive engagement with the seat surface in the closed condition. In Figs. 1 and 2, the closure-plate 20 and seat are elliptical, with the points of maximum extent in the direction of the stem (Y) axis offset from that axis in the direction of the transverse (X) axis. The S-plane containing the seat engaging line 21 of the plate 20 in the closed condition is inclined to the Y-axis and the seat is configured such that an arc described by each point on the plate periphery as it moves to the closed position makes an angle with the seat surface, thereby ensuring that each point can be compressed against the seat surface. In a modification (Fig. 7) the Y-axis is tilted, the S-plane arranged skew-wise and the valve seat is cylindrical but still of elliptical section. Fig. 13 is a modification of Fig. 7 in which the Y-axis is restored to the vertical and the end faces 34, 36 lie in skew planes parallel to the S-plane. The closure plate includes a sealing ring 46 which supplements the metal-to-metal contact between the plate periphery and the seat surface. An alternative non-circular configuration for the valve plate is shown in Fig. 15 where the S-plane is normal to the flow-way (Z) axis and the Y- axis is vertical. The periphery of the closure plate need not be planar, and either the seat or the closure plate can be deformable. |
