Abstract: A pumped medium supplied to a suction chamber of the pump is first introduced under the action of the plunger into a working chamber of the plunger and then into a pressure chamber and a subsequent pressure line. The seats of a suction valve and of a discharge valve are arranged on a housing of a central valve, which can be inserted into a cylinder head through an opening formed in a cylinder head which can be closed by means of a base part. A piston-like element which is provided with intermediate seals between the base part and the central valve housing serves to secure the position of the central valve housing. The piston-like element is acted on at both its end faces, due to the provision of spacing chambers, by the pressure of the pumped medium in the pressure chamber. The seals are wedge-shaped so that they are increasingly urged radially outwardly against the cylinder head under axial loading.

Abstract: A piston pump arrangement is provided which includes a drivable crank shaft supported in a crank drive housing for rotational movement. The crank shaft is drivingly connected to horizontally disposed axially reciprocating pump pistons. In order to facilitate driving of the crank shaft from either the right side or the left side to accommodate the available space requirements and driving motor connections, the crank drive housing is provided with fastening support surfaces arranged symmetrically with respect to a plane through the axis of the crank shaft and the axes of the pump pistons. To accommodate attachment of auxiliary aggregates, such as lubricating/cooling circuit mechanisms, fastening points for such aggregates are also arranged symmetrically with respect to the plane of the crank shaft axis and the pump pistons.

Abstract: A valve arrangement for venting conduits in pumping systems having several pumping units for delivering a gas or vapor generating liquid includes a double-seat valve in which the valving element moves between two extreme closing positions and an intermediate position in which the venting conduit is momentarily open; as the venting conduit is connected at one end with the gas collecting zone in one pumping unit and at the opposite end with the liquid discharging zone below the delivery valve so that the double seat valve is automatically controlled by the pressure difference resulting due to different operational phases of the pumping system.