Theoretical Underpinnings of the Parameters of Device for Cleaning Grain from Ergot Sclerotia

Abstract

Introduction. The grain collected by a combine contains not only full-weight grain, but also weeds, including harmful ones, which include toxic ergot sclerotia. Existing grain cleaning machines cannot provide complete separation of toxic ergot sclerotia during a single technological process, because of the similarity of physical properties. A complete separation of ergot from grain in one technological process is possible by density using aqueous solutions of inorganic salts. Therefore, an urgent issue is the development of a machine for separating harmful impurities in a wet way. Materials and Methods. We consider the fall of grains of rye, wheat, barley and oats, which have a shape close to ellipsoidal, from the outlet of the loading hopper into a liquid with a density of 1.0; 1.05; 1.10 and 1.15 ∙ 103 kg/m3. Theoretical explorations were undertaken for grain density (1.2...1.5) ∙ 103 kg/m3, a length (5.0...10.0) ∙ 10–3 m, a width (1.4...3.6) ∙ 10–3 m and thickness (1.2...3.5) ∙ 10–3 m by mathematical modeling methods using the laws of mechanics and hydrodynamics. Results. For the development of a machine for a wet separation of harmful impurities, the height of the location of the outlet of the loading hopper relative to the surface of an aqueous salt solution was estimated. The formulas are obtained for determining the minimum height required to overcome the Archimedean ellipsoid grain force, surface tension forces and fluid hydrodynamic resistance, taking into account the law of conservation of energy. Discussion and Conclusion. It was found that the minimum height of the loading hopper outlet location relative to the liquid surface depends on the orientation of the grains at the moment of entering it, their linear dimensions and density, as well as the density of an aqueous salt solution. The height of the outlet of the loading hopper, necessary for guaranteed overcoming of the surface tension of the liquid by all grains, is 57.1 ∙ 10–3 m.