In this paper the problem of volumetric flow rate regulation is considered. The change of angular position of an element mounted axially inside of the cross flow fan impeller creates different aerodynamic performances: yt = f (j), ys = f (j) at the same rotational speed and in consequence the qualitative diversification of fan operation is obtained. It gives possibility to use a cross flow fan for several applications depending on an actual requirement respecting to volumetric flow rate or pressure coefficient. The shape of inner element as well as its angular position have an important influence on the flow structures so a method of volumetric flow rate control without necessity of rotational speed change is proposed. This way of cross flow fan flow rate control, commonly made with use of frequency converter, seems to be more effective for reduction of an energy consumption and gives an evidenteconomic advantage.