Abstract. Due to the high productivity and the wide range of crushing, rotor crushers are widely used for crushing grain for animals. The paper deals with the movement of the rotor with moving masses as an example of a hammer rotor of the crusher, which can be imagined as a system with several degrees of freedom with nonstationary constraints, taking into account the forces of resistance and nonharmonic periodic external influences. For the generation of differential equations of the movement of the system, we used the Lagrange equations of the second kind, in the solution of which decomposition of the movement according to the proper forms of oscillation was applied. The nature of the change in the external impact was determined experimentally. Distribution of its intensity was estimated by the traces of the crushed particles left on a previously painted lateral surface of the crushing chamber.Keywords: grain crusher, the Lagrange equations of the 2nd kind, kinetic energy. IntroductionGrain is a valuable source of feed for farm animals. The body of the animal assimilates more completely nutrients from crushed grain.Crushing grain is widely used for the preparation of feed for the animals on farms and in the mixed feed industry. For crushing grain, rotary (hammer) crushers are widely used [1][2]. Such crushers have high productivity and provide a wide range of grinding.During the research of the operation of rotary grain crushers, the main regularities determining the productivity, the degree of crushing, the energy consumption, etc. were revealed.However, new technological and technical requirements are imposed to the operation of hammer crushers and a process of constant improvement of the structures is underway. Therefore, the development of these machines with justified optimal design parameters is an important and urgent task.The hammers of the crusher are pivotally connected with the rotor, and, because of uneven feeding of the grain and the resistance forces, they perform some oscillatory movements relative to the point of attachment. Oscillations of the hammers affect the efficiency of the machine. Establishment of theoretical patterns of the oscillation process of hammers allows us to determine the optimal ranges of parameters and make appropriate corrections in the design already at the design stage.A number of research papers [3][4] have been devoted to the study of the oscillations of pivotally fixed operating tools of agricultural machines; however, theoretical and experimental studies of the grain-hammer interaction that contribute to the improvement of the grain crusher structures are not complete and require refinement.The aim of this work was a mathematical description of the impact of grain upon the hammer rotor and the determination of the influence of the location of the centre of masses of the hammers upon the process of their oscillations when deviating from the equilibrium movement.

Food products made of grain are the main source of human nutrition and feed for farm animals. One of the main reserves for increasing its production is sowing with high-quality material, purified from various impurities and pathogens. To protect it from various diseases, etching is used. The most effective way to implement this technological operation is wet pickling with simultaneous release of grain impurities. For implementation of a corresponding device, an estimate was made of the minimum drop height of a weevil which is necessary to overcome the surface tension of a liquid. Pea seeds with a shape close to a sphere were used as objects of research. Therefore, a spherical caryopsis with density ρз = (1.15…1.45)∙103 kg/m3, diameter 2rз = (3.5…10.9) ∙10-3 m was taken as a model of the seed. We investigated the fall of separately taken spherical caryopses with minimum (2rзmin. = 3.5∙10-3 m), average (2rзmid. = 7.2∙10-3 m) and maximum (2rзmax. = 10.9∙10-3 m) linear dimensions having a density ρз = 1.15; 1.25; 1.35 and 1.45∙103 kg/m3, on the surface of an aqueous solution of the dressing agent with a density of ρж = 1.00; 1.03; 1.06; 1.09; 1.12 and 1.15 ∙ 103 kg/m3 with the corresponding coefficients of surface tension σ = 0.0727; 0.0755; 0.0771; 0.0786; 0.0801 and 0.0816 N/m and hydrodynamic resistance coefficients c = 0.4 (0.5 for ρж = 1.12 and 1.15 ∙ 103 kg/m3). The etching process was considered at a temperature of 20°C. The minimum drop height h for overcoming the surface tension of the dressing solution by all caryopses with physical and mechanical parameters with the indicated values should be 15.5 ∙ 10-3 m