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.

Abstract: A high pressure plunger pump, in particular for forwarding water and water with additives, comprises a plurality of plungers 20 which are driven by a crankshaft journalled in a drive housing 10. The free ends of the plungers 20 are each guided in respective pump chambers 22 of an induction-discharge housing 12 which is connected to the drive housing 10. The induction-discharge housing 12 is a one piece housing of generally L-shaped cross-section. The pump chambers 22 are arranged in one limb of the L-shaped housing and communicate with an induction chamber 27 via spring biased inlet valves 27 provided in axial extensions of the pump chambers. A discharge chamber 31 extends through the other limb of the L-shaped housing and is fed from the pump chambers via outlet valves 29. Both the inlet and the outlet valves 25, 29 are secured in position by respective threaded plugs. The use of a one piece L-shaped housing brings a number of substantial benefits.