Search

The topic of the paper is the determination and justification of the rational design and kinematic parameters of clod breaking tools in rotary potato harvesters with the aim of improving their separating efficiency. A new mathematical model has been developed for the motion of a soil particle on the working surfaces of the cone-shaped and cylindrical vanes in the rotary tool of the new design developed by the authors. Differential equations have been generated for the motion of a soil clod as a material particle from the moment of its arrival to the surface of the vane until the moment of its departure from the said surface. As a result of the completed investigations, relations have been established between the time of contact and absolute displacement of the soil particle and the velocity of its departure from the rotor vane surface, on the one hand, and the kinematic and design parameters of the rotor, on the other hand. For example, when the machine translation velocity increases, the absolute displacement of the soil particle within the interval from the time zero to the moment of its departure from the vane surface increases from 0.59 m to 0.65 m, the velocity of soil particle departure from the vane surface - from 1.61 m s-1 to 1.81 m s-1. The highest values of the absolute displacement of the soil particle and the velocity of its departure from the vane surface are achieved at a machine translation velocity of 2.0 m s-1. The time of the contact between the material particle and the vane surface decreases with the rise of the translation velocity. When the rotor rotation frequency varies within the range from 20 min-1 to 100 min-1, the absolute velocity, with which the soil particle leaves the vane surface, rises to 4 m s-1. The duration of the contact between the material particle and the vane reaches its maximum value of 0.33 s, when the rotor rotation frequency varies within the range of 30-40 min-1. [ABSTRACT FROM AUTHOR]

The authors have set an aim in relation to the development of a novel rotary potato harvesting machine design and the substantiation of rational design and process parameters for the clod crushing tools in the machine in order to improve its separation capacity. A novel design solution has been suggested for the process of crushing the two adjacent potato rows with the vanes of the vertical rotor and the expediency of using the methods of crushing clods in the two adjacent potato rows in advance has been justified. Also, the more rational placement of the clod crushing tools in the potato harvesting machine has been suggested. Following the completed research, the geometrical parameters of the vertical rotor have been substantiated, in particular, its diameter dр = 0.65–1.0 m and height hzag = 0.27 m. Additionally, the process parameters have been substantiated for some other tools crushing the clods, in particular, the angle of inclination of the share’s working face, which has to be equal to 10°, the elevator belt width bel = 1.05 m, the linear velocity of the belt Vp = 1.95 m s–1, the belt agitation amplitude Аst = 18 mm. If the soil moisture content is equal to W = 18.4%, the soil separation rate rises insignificantly, when the rotor diameter increases within the range of 0.65–1.0 m, moreover, at Vm = 1.0 m s–1 it varies within the range of 85.3–87.2%, at Vm = 1.5 m s–1 – within the range of 87.0–92.7%, at Vm = 2.0 m s–1 – within the range of 86.0–89.1%. The best performance is achieved at a rotor rotation frequency of nр = 100 min–1 and a translational velocity of Vm = 1.5 m s–1, in which case the soil separation rate S is equal to 93.5%. The tuber damage rate Pb decreases from 4.2% to 1.5%, as the rotor diameter dр increases from 0.65 m to 1.0 m, the translational velocity of the machine Vm – from 0.8 to 2.2 m s–1 at the rotor rotation frequency nр = 50–100 min–1. [ABSTRACT FROM AUTHOR]