Wind sifter for finer grading of particles - has several sorting stations with air inlets into main pipe line

摘要

The wind sifter for sorting out non-homogeneous waste substances, esp. in granaries comprises main pipe line (25) in which a primary air current containing the waste substances flows upwards. The pipe line has an irregular cross-sectional area with enlarged points which form separating stations distributed along the pipe line so that the waste substances can be separated out from the air current by their density. Each station is formed in part by an inclined wall (26) of the main pipe (25) whilst an outlt channel (3) for the waste substances is connected at its upper end to the main pipe at each station. An air inlet unit (27) is also provided at each station to introduce a secondary air current into the main pipe line to counteract the primary current. The inlet unit guides the secondary air current crosswise through the particles being separated out at the relevant station so that the lighter waste substances and t]e secondary air current which carries them along strike the inclined wall of the main pipe and continue along same so as to pass back up again into the main air current so as to convey the lighter particles to the next sorting station (32).