TYPICAL ROTO-SIZER CLASSIFICATION CURVE
The Roto-Sizer consists of a cylindrical chamber, orientated along its vertical axis, with a horizontally-mounted classifying rotor. Feed material is fed into the upper section of the housing where it falls by gravity and is washed by uprising air injected into the classifying chamber. This elutriation is the first step in the Roto-Sizer’s classification that actually separates most of the feed’s fine and coarse particles. The uprising air carries the fines to the classifying rotor while the coarse particles fall against the air flow and are discharged from the coarse outlet at the bottom.
The second step of the classification is performed at the edge of the classifying rotor. The high speed of the rotor creates a high-velocity air stream at the rotor’s periphery. This high-velocity air further washes the fines from the coarse particles before the fines enter the open vane areas of the rotor. This forced-vortex area also deagglomerates and separates the fines in preparation for final classification.
The final classifying step occurs within the rotor. Due to the high centrifugal forces created within the rotor, coarse particles are expelled back into the main chamber where steps 1 and 2 are repeated. The fine particles flow with the air to the fines outlet. A precise classification is established by varying the rotor speed and air flow to create the desired cut size and sharpness.