which expediently is arranged at a slight inclination with respect to the horizontal direction the air splitter 105 divides the air stream 101a into a partial air stream 102 flowing in chamber 100a and a partial air stream 103 flowing in chamber 100b underneath the air splitter 105 the chamber 100b is bounded by a guide element 107 which is supported inside a side wall 106a of a container 106 by an articulation 108 to be pivotal about a horizontal axis in the separating zone above a side wall 106b of the container 106 opposite the downstream end of the air splitter 105 there is arranged a baffle element 109 such as a sheet metal flap which forms an acute angle with the partial air streams 102 and 103 the baffle element 109 is pivotal about a horizontal axis by means of an articulation 110 to the inside of the wall 106b there is attached by means of an articulation 112 a guide element 111 such as a planar or concave as viewed from the air splitter 105 plate which is rotatable in a vertical plane also referring now to fig2 at a short distance upstream of the air splitter 105 there is arranged a.