The article is devoted to increasing the efficiency of the process of vibro-pneumatic separation of grain and seeds by the intensification of the separation process under the additional influence on the grain layer of directive forces on particles. Through mechanical-mathematical and simulation models of particle movement in a grain layer and on a sieve surface, taking into account the separators of grain material, the layer dynamics of the mixture as well as the individual particle movement in the layer and their relationship with the constructive-kinematic and regime parameters of the vibro-pneumatic separation process have been identified.
The roller for seeds of different sizes, a variable-size pneumatic cylinder precision seed metering device was designed, which could realize the precision seeding of different diameter seeds without changing the roller. The structure and working principle of seed metering device were explained, and the structural parameters of the main components of the seed meter were determined. The ANSYS was used to analyse the influence of the size of the negative pressure inlet pipe and the shape of the eyelet on the airflow velocity in a negative pressure chamber. Based on the above optimal structure, the orthogonal experiment of seed metering device was carried out. Testing results showed: under the negative pressure of 4 kPa, roller speed of 16.93r/min and the wind speed of 11.48m/s, the seed metering device had the best seeding effect. The qualification rate of the seed metering device was 92.37%, the miss-seeding rate was 3.74% and the over-seeding rate was 3.88%.
The design of a helical surface tillage tool made of a developable helicoid section has been calculated using the methods of analytical and differential geometry, the theory of surfaces, the systems of computer-generated graphics and mathematics. A helical tool in the form of a skeleton cylinder made of bars, where there is a helical surface made of arranged sheet metal, has been developed. Such a design prevents a helical surface from becoming clogged with soil. The suggested tool operates as a roller and the soil can easily pass through the gaps between the bars. New helical harrow tools have been designed and made for this experiment. An experimental harrow equipped with helical tools has been made and used to conduct a field research. The research was aimed at determining the optimal kinematic parameters and the pattern of field movement, which allow performing the technological process of soil tillage with the performance indices that meet the agricultural requirements.
Conveyance of a particle by a vertical screw, which is limited by a coaxial fixed cylinder Differential equations of relative particle motion along the periphery of a vertical screw have been deduced which rotates about its axis and is limited by a coaxial fixed cylinder. The equations have been solved by applying numerical methods and the trajectories of relative particle helical motion, that is to say, movement along the edge of a screw, which is common for a screw surface and for a limiting cylinder, have been built. The force of particle friction on the screw surface and on the surface of a cylindrical cover has been taken into consideration. The cases, when a helix angle, that is to say, the angle of screw edge inclination, is less than the angle of particle friction on the surface of a screw, when it is equal to a friction angle and when it is higher than a friction angle, have been considered. In addition, a specific case, when a screw is fixed and a particle moves downwards by gravity, which takes place in spiral chutes, has been analyzed. Kinematic characteristics-time curves have been presented.
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