Abstract: A pump piston construction for mud pumps and the like incorporating a resilient sealing member that establishes a pressure enhanced seal between the piston and pump cylinder. A bearing and anti-extrusion member composed of a relatively hard and flexible friction resistant plastic material is structurally interrelated with and may also be bonded to the sealing member. The anti-extrusion member is supported by an annular rigid flange of a piston hub about which both the sealing member and anti-extrusion member are received. The anti-extrusion member serves as a bearing to minimize wear of the piston and cylinder and is yielded radially outwardly responsive to fluid pressure transmitted through the resilient sealing member and functions to prevent extrusion of any of the resilient material of the sealing member into the space between the piston and cylinder.

Abstract: Pneumatic boosters basically comprise a casing and at least one movable wall disposed therein dividing the casing into two chambers. The differential of pressure between a low pressure in one of the two chambers and atmospheric pressure in the other of the two chambers provides the boosting effect. The diaphragm plate of the movable wall is normally made of relatively heavy sheet steel. According to the present invention a weight reduction and a saving of material is accomplished by providing openings in at least that portion of the diaphragm plate that extends substantially radially from the axis of the booster.