Abstract: The invention relates to an apparatus for sifting feedstock, comprising: a. a static sifter that has a ventilated bottom which is oriented at an angle to the vertical and is penetrated by sifting gas; b. an inlet for feeding the feedstock to the ventilated bottom; c. an outlet for the coarse material; d. a dynamic sifter that is mounted downstream and encompasses at least one rotor with rotor blades and a horizontal rotor axis; e. at least one outlet for the sifting gas loaded with fine material; and f. a housing inside which the static and the dynamic sifter are arranged. The housing area surrounding the dynamic sifter is designed as a housing spiral such that the sifting gas flows against the rotor in a substantially tangential direction. The rotor rotates counter to the direction of flow of the sifting gas in the housing spiral.

Abstract: The invention relates to an apparatus for sifting feedstock, comprising: a. a static sifter that has a ventilated bottom which is oriented at an angle to the vertical and is penetrated by sifting gas; b. an inlet for feeding the feedstock to the ventilated bottom; c. an outlet for the coarse material; d. a dynamic sifter that is mounted downstream and encompasses at least one rotor with rotor blades and a horizontal rotor axis; e. at least one outlet for the sifting gas loaded with fine material; and f. a housing inside which the static and the dynamic sifter are arranged. The housing area surrounding the dynamic sifter is designed as a housing spiral such that the sifting gas flows against the rotor in a substantially tangential direction. The rotor rotates counter to the direction of flow of the sifting gas in the housing spiral.