Abstract: A sifter-screening machine for loose material, especially flour, including an inlet for the material, downstream thereof a screen through which the material can be conveyed via an air stream, and downstream thereof an outlet for screened material. Disposed in the conveying route of the material, downstream of the screen, is a zone of reduced static pressure followed in the conveying direction by a conveying zone having an increasing cross-sectional configuration. The weight of the material just upstream of the outlet is at least nearly equal to the oppositely directed pressure of compressed air below an air-permeable element for supplying the material to the outlet.