SEPARATION METHODS AND SEPARATORS OF GRAIN MASS

Grain is a valuable raw material for food production, as well as for the production of bioethanol, alcohol, feed and medicines. Technologies of storage and primary processing of grain involve the separation process of grain mass. The quality and cost of grain largely depend on the efficiency of grain separation process. There are preliminary, primary and secondary cleaning of grain. Impurities from the grain mass are separated due to differences between their physical and mechanical properties and the properties of the grain of the main crop. These properties include: size and shape, aerodynamic properties, density, surface texture of grain mass components, coefficients of internal and external friction, elastic properties, humidity, color, etc. Different separation methods are used to separate the components of the grain mass by physical and mechanical properties, such as gravitational, mechanical, pneumatic, friction, magnetic, optical, electrical, X-ray, hydraulic and combined. Gravitational, mechanical and pneumatic grain mass separation methods are the most used. To separate from the grain mass of all impurities that have different physical and mechanical properties and nature, use a combined separation method, which involves the simultaneous or sequential separation of components of the grain mass on several grounds of divisibility. The grain mass separation method is chosen taking into account the feature that allows us during the separation to ensure the most complete separation of impurities or to divide the grain mass into fractions. Gravitational, electrostatic, magnetic, optical, pneumatic, sieve, belt and friction separators are used for separation of grain masses. For cleaning and separation into seed and food grain fractions, separators with sieve working surfaces of different construction are mainly used. Based on the results of the analysis of sieve work surfaces, their classification and classification of sieve orifices are formed.