valve is opened 3 close metering valve 4 metering valve is closed the quantity of medium filled into the containment 5 corresponds to the area under the curve between points 1 and 4 if the pressure in the supply line 3 changes then the curve changes to the effect that the approximately horizontal path of the curve between points 2 and 3 is shifted either upward or downward and the fill quantity would be changed thereby the influence of the feed pump 10 on the filling process will now be described in greater detail feed pump 10 must be controlled such that the horizontal line between points 2 and 3 in the filling diagram has approximately the same height for all filling instances this is achieved by coordinating the shut off signal for the feed pump 10 with the closing signal for the metering valve 30 if the feed pump 10 supplies when the metering valve 30 is closed then pressure will build in the supply line 3 at the next opening of the metering valve 30 a spurting of the medium results such spurting is very difficult to register with the known flow measuring devices in such case the measurement values delivered by the flow measuring device 20 are subject to considerable inaccuracies and thus the close command for the metering valve 30 may not come at the correct point in time altogether this would.