Mixer for gaseous media and method for mixing gaseous media

The invention relates to a mixer for gaseous media with a Venturi tube through which a gas flows in the tube axis direction and in the region of narrowed cross-section (7) on the tube wall inlet openings (8) are provided for admixing gas, wherein the passage cross sections ( 21) of the inlet openings (8) during operation during the mixing process by means of control elements (14) are variable and a method using the mixer.