Abstract: A reciprocating jetting water pump primarily for use on a vacuum truck is disclosed. The jetting water pump includes a pair of reciprocating pistons that are each movable within an outer cylinder mounted to a center block. Each of the outer cylinders is mounted to the center block by a plurality of tie-rod that each extend between the center block and an end plate. An airflow passageway is formed in the center block to vent air trapped within the open interior of the first outer cylinder during reciprocating movement of the piston in the first outer cylinder. A control system mounted to the vacuum truck senses the pressure of water leaving the jetting water pump and controls the supply of pressurized hydraulic fluid to the jetting water pump to maintain the water pressure at an operator selected value.

Abstract: A reciprocating jetting water pump primarily for use on a vacuum truck is disclosed. The jetting water pump includes a pair of reciprocating pistons that are each movable within an outer cylinder mounted to a center block. The outer surface of each of the pistons includes a polymer surface that is closely spaced to the inner surface of the outer cylinder. The outer surface includes a pair of spaced polymer strips separated by a seal to enhance the seal between the piston and the outer cylinder. Each of the outer cylinders is mounted to the center block by a threaded connection. A control system mounted to the vacuum truck senses the pressure of water leaving the jetting water pump and controls the supply of pressurized hydraulic fluid to the jetting water pump to maintain the water pressure at an operator selected value.