Abstract: A concrete pumping unit comprising a pair of parallel piston pumps, alternately placed in communication with a concrete supply conduit and with a concrete delivery pipe, through a single baffle blade valve and respectively driven by coaxial fluid pressure piston cylinders is disclosed. The cylinders are interlocked with each other by a pipe which places in communication the chambers of said fluid pressure cylinders, opposite to the chambers in which the pressurized fluid is supplied and discharged through orifices near the ends of said cylinders. A hydraulic circuit is provided for placing a fluid supply pump, in communication with the fluid pressure piston cylinder performing the suction phase, while the orifice of the other fluid pressure piston cylinder is placed in communication through another circuit including, a four-way changeover electro-valve and an actuator distributor device with a discharge reservoir.

Abstract: A pumping apparatus for wet concrete and the like comprising a pair of piston pumps having parallel axes, interlocked to one another and operating in phase opposition, the orifices of which are alternatively put in communication one with the conduit feeding the wet concrete and the other with the delivery conduit and vice versa by means of a reciprocally movable baffle blade valve having two operative limit positions, characterized by the fact that the pump pistons are each actuated by a single-acting jack, being provided means to at first move the baffle valve into either of its operative positions by means of a hydraulic control device, and then to actuate the jack which is about to begin its intake stroke only when the baffle blade valve has reached one of the limit positions, and to reverse the position of said baffle valve into its second limit position before the beginning of the compression stroke of the pump actuated by said jack and vice versa, and means for interlocking the movements of the jacks, a