Introduction. The task of high-quality cleaning of root crops from soil is relevant at all stages of preparing roots for further processing, feeding to animals, and selling. In the machines for cleaning root crops from soil, there is mostly used water. With the water consumption for washing a unit of mass of soiled root crops up to 200-400%, the use of water creates a huge problem including soiled water treatment. The dry method of cleaning root crops is most common in practice and involves the use of appropriate machines, which are not always able to provide the required quality of the finished product. Therefore, the problem of developing a root crop cleaner by the dry cleaning method and substantiating the cleaner optimal parameters to ensure the required quality of the finished product is important and relevant. Aim of the Study. The study is aimed at substantiating theoretically the parameters of a root cleaner with adjacent rollers rotating at different frequencies. Materials and Methods. The subject of the study is the technological process of cleaning root crops with the dry method. To realize this process, there has been developed a cleaner of root crops from soil, the key features of which are the use of a roller transport-cleaning working element and the ability of adjacent rollers rotate at different frequencies. Individual design parameters of the proposed cleaner have been substantiated theoretically. Results. There have been determined the forces acting on the root crop when it is located on rotating rollers. There has been found the dependence of the angular displacement phi(t), angular velocity omega(t) of the root crop located on rotating rollers, and the dependence of the coefficient of root crop sliding friction on the rollers on the angle alpha, which determines the relationship between the main design parameters of the working element, in particular, the diameter of the rollers and the distance between them, and the physical and mechanical properties of the root crops. Discussion and Conclusion. The studies of the root crop cleaner conducted in laboratory conditions have confirmed the results of theoretical studies and showed that with a length of the transport-cleaning working element of 2 m within a time of 34,4 s it is possible to achieve an efficient cleaning of 78% when the cleaner is equipped with 16 rollers and the ratio of the rotation frequencies for odd and even rollers is 220/250 min-1. The study results are useful for creating and modernizing technical means for post-harvest processing of root crops, conducting further studies on technological improvement of similar means of mechanization of agricultural processes, and for using in the educational process to train technical specialists.

At present, the potato's mechanized harvesting rate in hilly and mountainous areas is very low. The reasons for this are that in heavy soil, the separation of potato rhizomes from soil or vines is not sufficient, harvesting machinery is seriously damaged by the potato epidermis, and the harvested potato is easily buried in soil, resulting in a missed harvest. In this paper, a two-stage cleaning potato harvester with wave-type and roller-group-type separating mechanisms was designed, and its overall structure and working principle are introduced in detail. The new cleaning mechanism can increase the effective separating length and effective contact area of the potato-soil mixture so as to achieve the purpose of removing clay and heavy soil. The main separator uses a structure that combines offset waves with opposite waves and a staggered arrangement of large-small diameter straight bars. The secondary separator adopts a device combining left-hand and right-hand separating rollers. The discrete element model of the whole machine was established, and the results of the theoretical analysis were verified by simulation. The key factors affecting the harvest quality were analyzed by variance analysis and response surface analysis, and the field experiment was carried out with the rate of clean potatoes, damaged potatoes, and peeled potatoes harvested as the indexes. The field experiments showed that the machine achieved a rate of photos on or out of the earth of 98.87%, a damaged potato rate of 0.91%, and a peeled potato rate of 1.13%. The research results provide theoretical support and a technical reference for the design and optimization of potato harvesters, as well as the improvement of the potato-soil separating efficiency and harvest quality.