Concrete pump valve with cylindrical seat - has axially movable stem with radially expandable sealing member and hard seat-clearing element

摘要

The valve is intended for coarse-grained and/or abrasive or clogging material, particularly in a concrete pump. It comprises a cylindrical seat (1) for a piston-shaped closure member (3) which is axially movable (7) by means of a valve stem (4). The forward end of the member which on closure enters the seat is provided with a seat clearing element (10) in a hard material. Behind this head there is a sealing member (8) in a resilient material which is radially expanded by means (12) on the stem to effect a seal. The minimum clearance between the element (10) and the seat (1) is preferably smaller than the average grain size of the material passing through.