Abstract: A pump is shown with a sealing means for providing static seals along liners slidably receiving the pistons of the pump. The sealing means includes a metal cylindrical ring having a generally wedge-shaped outer edge. In the wedge-shaped outer edge is bonded a resilient sealing material, which sealing material extends outwardly from the metal ring at a small angle. The resilient sealing material also extends beyond one end of the metal ring with an undercut on the innermost edge of the resilient material. After assembly, the metal ring provides a stiff assembly necessary for intermittent operation of the pump in climates having large temperature variations. The resilient sealing material provides sealing along two adjacent surfaces of the liners. Other seals along the liner may be replaced to include combinations of metal for stiffness and resilient material for sealing.

Abstract: A gate valve having a valve body particularly designed and constructed of a "slim" design, or of a minimum overall length whereby the valve may be interposed in a flow line in a minimum of space.

Abstract: An improved hydraulic control means for check valves to prevent slamming of a clapper against a seat. The clapper of the check valve is connected via a crosshead to an hydraulic cylinder and a piston contained therein controls the closing of the check valve. The hydraulic cylinder has means restricting flow of fluid from below the piston in the hydraulic cylinder to above the piston in the hydraulic cylinder, but permits unrestricted flow in the opposite direction. Relief valves are included to prevent overpressurization in the hydraulic cylinder. A precharged accumulator allows for fluid expansion and contraction in the hydraulic cylinder, plus replacing fluid lost by leakage.