non square shapes the time of the slow filling until the achievement of the defined filling level is chosen in such a way so that the filling level reached by the heavy gas is also sufficient during the filling of insulating glass units of extreme shape so that during the subsequent increase of the filling rate no significant increase in the turbulent mixing is supported until this point in time the filling rate is held so low so that the turbulent mixing of the heavy gas and the air remains below a specified minimum value and at the end of this time required to reach the average filling level the filling rate and the evacuation rate are simultaneously increased stepwise in such a way that again considering the filling level now reached the turbulent mixing remains below the specified minimum value the magnitude of the stepwise increase in the filling and evacuation rate adjusts itself likewise according to the size of the ascertained volume since by a very small volume a large increase in the rate is naturally not sensible basically a sliding increase of the filling rate depending upon the ascertained volume is also possible by very large volumes to be filled the filling and evacuation rates if necessary can be similarly increased stepwise upon.