Hydraulic piston pump assembly

Claim 1

A piston pump for conveying concrete, comprising: A. a pair of concrete-conveying cylinders, B. a pair of alternately operating pistons reciprocable respectively in the cylinders, C. a concrete-conveying output pipe communicating with the cylinders, D. a valve housing between the cylinders and the pipe, E. a hopper located above the valve housing for supplying concrete, and F. a rotary valve body located within and turnable in the valve housing on an axis at right angles to a plane containing both of the concrete-conveying cylinders, the valve further comprising F 1. a radial-tangential recess forming a concrete input suction port recurrently exposed to the hopper for suction of concrete from the hopper into the conveying cylinders in alternation and, F 2. a radial surface on each side of the radial-tangential recess, forming, together with the valve housing, an output port which is continuously open to the output pipe and which, in alternation, is open to the conveying cylinder which is not then open to the radial-tangential recess, whereby, on a suction stroke of each cylinder, the valve is positioned to place the radial-tangential recess in communication therewith, and, during a pressure stroke of each cylinder, the valve is positioned with the output port formed by the radial surface in communication therewith.