A mathematical model of grain separation with an air-gravity separator

The paper presents a mathematical model of the separation process of grain components in an air-gravity separator for grain cleaning, which consists of a head screen, pneumatic duct, pre-distribution unit and two columns with combs cascades. A basic block diagram of the air-gravity separator for grain cleaning is given. The developed air-gravity separator differs from all existing ones in that: at the entrance to the pneumatic duct, which has several partitions of a rectangular cross-section, the head screen is installed, in order to isolate extremely large impurities; and to divide the grain material into two fractions: the main grain with fine impurity and the main grain with coarse impurity. At the beginning of the air-gravity separator a pre- distribution unit is installed. It consists of a system of combs with holes that let in the particles of the fine impurity and a part of the main grain. For the effective extraction of the particles over the solid grain pans the reflectors are installed.