Abstract: A high pressure liquid pump has a drivable swash plate and a plunger which is acted on by the swash plate and guided in a cylinder bore of the pump housing. In the region of the front end of the plunger facing the swash plate a valve arrangement is provided between a low pressure chamber and a pump chamber. A second valve arrangement is arranged between the pump chamber and a high pressure chamber. The plunger has a transverse bore which stands in communication with the low pressure chamber during the pump movement and also has an axial bore extending from the transverse bore to the front end of the plunger, with the axial bore being enlarged towards the front end while forming a ring-like valve seat, with a valve insert being arranged in the broadened section of the axial bore.

Abstract: A relief valve for high pressure pumps is described which is characterized by its extremely compact construction and complete reliability against leakage. The relief valve has a valve ball in the bypass path which is pressed by a high and preferably adjustable force against the valve seat, by means of a compression spring which is located entirely in the housing of the unloader. The spigot which acts against the ball in the bypass path is actuated by means of a piston which is acted on by the output pressure over its entire cross-sectional area.

Abstract: A pump which operates with several plungers is described with the plunger preferably being actuated via an eccentric drive unit and, having regard to the particular volume of flow per unit time, using several small plungers rather than a lesser number of comparatively large plungers, and accordingly operating with a large number of small volume displacements at a comparatively high speed of rotation. In this arrangement the suction chamber is centrally arranged in the pump body and the high pressure outlets of the pump chambers, which open into a common pressure chamber of ring-like construction, extend at least substantially in a radial direction.

Abstract: A pump for forwarding liquids is described which has at least one pump chamber with inlet and outlet valves and also a plunger which periodically varies the volume of the pump chamber. To avoid the problems of dry running with very rapidly running pumps, and in order to overcome the resulting danger of destruction, the pump is arranged so that the closing force of at least one inlet valve of each pump chamber is controlled in dependence on the movement of the displacement member.