Introduction.When harvesting grain crops, various trash and harmful impurities come to the combine bunker together with grains. These harmful impurities include egot sclerotia, which are poisonous. Various modern grain cleaning machines do not provide for complete separation of ergot sclerotia from grains, because of the closeness of their linear dimensions (width, thickness and length) and speed of soaring. Cleaning seeds from ergot sclerotia having the density less than density of grain, is possible in an aqueous solution of salt. For the mechanization of the allocation of sclerotium ergot from rye seeds by a wet method, the urgent issue is the development of a device for cleaning grain material.
Materials and Methods.The immersion of separately taken rye grains in water (ρzh = 1,0 ∙ 103 kg/m3) and aqueous solutions of sodium chloride (NaCl) with density ρzh = 1,09 ∙ 103 kg/m3 and 1,15 ∙ 103 kg/m3. The ellipsoid is taken as the geometric model of the grains. Theoretical studies were performed for the grain density ρz from 1,2 ∙ 103 kg/m3 to 1,5 ∙ 103 kg/m3, lengths lz from 5,0 ∙ 10–3 m to 10,0 ∙ 10–3 m, width b from 1,4 ∙ 10–3 m to 3,6 ∙ 10–3 m, and thickness δ from 1,2 ∙ 10–3 m to 3,5 ∙ 10–3 m based on the methods of mathematical modelling using the laws of hydrodynamics. For practical experiments, there was chosen the gains of the winter rye variety Falenskaya 4 having the gain density ρz from 1,1 ∙ 103 kg/m3 to 1,3 ∙ 103 kg/m3, length lz from 5,0 ∙ 10–3 m to 8,0 ∙ 10–3 m, width b from 1,4 ∙ 10–3 m to 3,6 ∙ 10–3 m, and thickness δ from 1,2 ∙ 10–3 m to 3,5 ∙ 10–3 m.
Results. The speed ʋz and duration tп of grain immersion in liquids are main parameters taken into account when developing a machine for cleaning the grain material from ergot sclerotia with a wet method. The values of these quantities determine the structural and technological parameters of the machine under developing. To determine these parameters, it is necessary to take into account the geometric shapes of the grains, which have a large variety. An ellipsoid with a small 2cz = δ, an average 2bz = b and a large 2az = lz axes is proposed as the closest to the shape of the grain. From the basic law of the dynamics of the grain movement in liquids of various densities ρzh a formula was obtained for determining its velocity, the calculated values for which are consistent with the experimental data obtained.
Discussion and Conclusion. It is established that the calculated values of the speed of grain immersion in liquids of different density are comparable with the experimental values of the same order. They are close and differ by no more than 10 %. This approach to determining the speed of grain immersion in a liquid can be used in developing a machine for cleaning a grain material with the wet method to substantiate its structural and technological parameters.
Influencing Factors on the Dielectric Breakdown Strength in F-gas Free High-voltage Switchgear
