the hydraulic system of the law and the use of the piston pump

摘要

In order to achieve the simplest possible operation and construction of a piston pump (15), the fluid is fed to the suction side (6) of the pump by means of a generally-known flow-pump (2) in an amount which at least corresponds to the maximum output of the pump (15). There can thus be achieved a considerable simplification of the construction of the pump (15), in that the valves (6, 7) becomes self-acting for reasons of the prevailing pressure. Moreover, the piston (9) can be disposed loosely in its bore and influenced mechanically solely for pressure, for example by means of a simple rotating eccentric (10), in that the return stroke of the piston (9) is effected by means of the fluid pressure in the pump chamber (14). Furthermore, the advantage is achieved that the pump's drive unit (12) can be separated from the actual pump unit (13), even during operation, whereby service and repair can be undertaken. Since the flow-pump (2) can be driven independently of the piston pump (15), the pump can be started up in the unloaded condition, in that the fluid can be fed to the pump via a valve (5) when the pump has reached its working speed. This spares the pump and eases its start-up.