Spiral air sifter - preventing coarse particles from entering discharge region for fine particles

摘要

An air sifter has a cylindrical, spiral sifting chamber, between rotary end faces, with air fed tangentially by an adjustable assembly of guide vanes, while coarse particles are conducted away by conveyor means at the periphery. Air and fine particles are discharged centrally from the sifting chamber through a discharge opening in the region of which is a sifter wheel with vanes which is mounted radially within and coaxial to the sifting chamber with its vanes between the rotary end faces. The vanes of the sifter wheel can be flat and in the form of rectangles, parallelograms or trapezoids.