| 摘要 |
<p>The present valve is especially adapted for use in conduits through which construction mixtures, such as concrete mixtures, flow. The valve cooperates with a pump having pistons in two respective pump cylinders. A valve housing forms a valve piston chamber having plane walls. The valve plug or piston has also plane walls to fit into the valve chamber with respective plane walls. Three pairs of ports are provided. One pair is connected to the pump cylinders. Another pair is connected to a discharge conduit and a third pair is connected to a supply container for the concrete mix. Preferably, the cross sectional shape of the valve chamber and of the piston plug is triangular. However, the cross sectional shape may also form a quadrangle. Providing the valve chamber and the valve plug piston with plane walls facilitates the manufacture of the valve and improves its sealing characteristics.</p> |
