Abstract: This disclosure relates to a pumping apparatus that includes a hopper for receiving concrete with a delivery line extending from the hopper and a cylinder cooperating with the hopper to deliver concrete to the delivery line. A valve has an outlet end connected to the delivery line and is pivoted within the hopper between two positions to alternately connect the cylinder to the delivery line and to the hopper for delivering concrete to the delivery line and then withdrawing concrete from the hopper for subsequent delivery. An adjustable wear plate is located adjacent the inlet end of the valve so that continuous contacting engagement can be maintained between adjacent surfaces of the valve and the plate. The valve also has rigidifying means associated therewith and is supported on the hopper in a manner to prevent distortion during movement thereof.