Importance

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Abstract

The invention relates to a hydraulic circuit arrangement, in particular for the drive of concrete distributor masts. The circuit arrangement comprises at least one hydraulic load (34, 35, . . . ), the latter being connected at the inlet side by means of a feed line (64) to the pressure outlet of a hydraulic positive displacement pump (60), and comprises at least one proportional valve (56) which is arranged in the feed line (64), is assigned one of the loads and, in its rest position, blocks the feed line (64), and in an operating position, forms a throttle aperture (57) with a variable opening cross section. Also provided in the feed line (64) is a reversing group (82), which in the standby state is connected to the tank (62) and in the operating position is connected to the at least one load (34, 35, . . . ). The positive displacement pump (60) has an adjusting element (58) which is controlled by means of a feed flow regulator (70) which is arranged in the pump branch (111) and comprises a directional control valve (71), one pilot control inlet of which is pressurized with the pressure (p) prevailing at the outlet of the positive displacement pump (60) and the opposite pilot control inlet of which is spring-loaded with a defined preload force and is additionally pressurized with the load pressure (pLS) prevailing downstream of the throttle aperture (57). In order to ensure reliable operation even in the start-up phase, according to the invention, a control group (107) which reacts to the load pressure (pLS) is provided with a switching valve (100) which, below a predefined minimum valve of the load pressure (pLS), places the adjusting element (58) of the positive displacement pump (60) into its position for maximum feed flow.

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First Claim