| 摘要 |
1,230,191. Valves. J. I. CASE CO. 30 April, 1968 [1 May, 1967 (2)], No.20326/68. Heading F2V. A valve for controlling flow of concrete in a pipe 102 has a replaceable closure member 160 or 204 which seats against the interior surface of the pipe, and which is provided with a wiping edge 148 or 210 to inhibit passage of concrete into valve chamber 104. The guide portion of the closure member is provided with piston rings 126, 132. In the construction of Fig. 3, closure member 160 is dome-shaped and resilient, and the wiping edge is constituted by a sleeve 146. Fig. 6 shows a modification in which the closure member is cut away to provide a surface 206 which, due to the fluid pressure in the pipe, assists opening of the valve. In a further modification (Fig. 8, not shown), a web is provided between surfaces 206, 208. |
