control surface of the control member when the consumer 6 is required to operate the directional control valve 5 is actuated to provide a connection between the pump 1 and the consumer 6 the pressure which builds up downstream of the directional control valve 5 is communicated by a so called ls line 12 load sensing line to the spring side of the required flow regulator 2 with the result that the previously prevailing equilibrium is disturbed and the pump 1 is supplied with a signal to increase the delivered volume then the delivered volume of the pump 1 increases and consequently also the delivered pressure of the pump above a specified delivered pressure the consumer 6 is set in motion the opening which is released in the directional control valve 5 here acts as measurement choke across which a pressure drop delta p occurs the delivered volume of the pump 1 is increased until a pressure drop delta p occurs across the measurement choke which pressure drop corresponds to the spring bias of the required flow regulator 2 if the second consumer 8 is switched on and if a greater load pressure prevails therein than in the first consumer 6 the delivered volume of the pump 1 is adjusted in accordance with the requirement of the second consumer 8 to prevent any increase occurring now in the speed of movement of the first consumer 6 the pressure compensator 9 assigned to the directional control valve 5 throttles the in flowing pressure medium until the pressure drop across the through flow opening measurement choke of the directional control valve corresponds again to the given value the speed of movement of the first consumer 6 is consequently not only independent of its own load.