The article presents the results of a study of a high-performance grain cleaning machine for the preliminary cleaning of grain pile with a closed aspiration system. The fl ow regimes of the "air-grain pile" mixture determined by the Reynolds number and the bulk concentration of particles are established. As a result of the modeling, further directions for improving pneumatic systems of grain cleaning machines were determined: the cleaning effi ciency of the Е 0 fraction of pure grain from light impurities, shriveled and crushed grain reaches 82%, the output cleanliness of the grain was 93.7%, and the loss of full grain to waste P z = 0,017%. The average speed of the air fl ow in the separating channel is U = 7.12 m/s, its coeffi cient of variation across the width of the separating channel is v = 12,7%. The results of the experimental data confi rmed the adequacy of using mathematical modeling of the air fl ow in the pneumatic system of a grain cleaning machine to substantiate the basic parameters of the pneumatic system.

The purpose of this work is a mathematical description of sieve frame structural and technological parameters necessary for the implementation of the technological process model of a grain cleaning machine operation. The paper presents the results of the study of the grain cleaning machine sieve frame operation. A kinematic study of a flat swivel multi-link mechanism of the grain cleaning machine sieve frame was made. The method of determining the coordinates of the sieve frame nodal points was developed to calculate their speed. Structural and technological parameters of the mechanism were also studied.

<abstract> <p>This article presents the results of a study of the sieve mill of a grain cleaning machine with a drive based on a linear asynchronous motor instead of a classic mechanical drive. The purpose of this work is to describe the structural and technological parameters of a sieve mill with a linear asynchronous drive to implement a mathematical model of the technological process of a grain cleaning machine work. A kinematic study of the flat hinged mechanism of the sieve mill of a grain cleaning machine was carried out, for which all geometric dimensions are known and the laws of motion of the leading link - the electric drive of the sieve mill based on a linear asynchronous motor are determined. As a result, the following were determined: kinematic modes <italic>k</italic>_{<italic>P</italic>} &gt; <italic>k</italic>_{<italic>B</italic>} &gt; <italic>k</italic>_{<italic>H</italic>} of sieve mill vibrations under various technological conditions; laws of motion of all parts of the mechanism of the sieve mill, movement, speed (0.34... 0.36 m/s) and acceleration (5.8... 6.9 m/s²) of the driven links; a mathematical model of the kinematic scheme of a sieve mill of a grain cleaning machine with a drive from a linear induction motor has been developed. The use of a linear induction motor compared to existing (classical) drive designs as a drive of a sieve mill in a grain-cleaning machine significantly reduces the metal consumption of the structure (drive shafts, transmission mechanisms, connecting rods, bearings are excluded from the structure), and energy consumption is also reduced due to pulse drive operation; makes it possible in a wide range of technological parameters regulation for various crops, including various physical and mechanical parameters of the crop being cleaned.</p> </abstract>

The purpose of this study is to increase the efficiency of the technological process of a combine harvester cleaning system. It involved the simulation of the actual work process, the identification of problem areas and the uniform airflow distribution across the width of the sieve mill. The method for determining the class of ‘air-grain heap’ flow in the combine harvester cleaning system is presented in order to provide the mathematical description of its technical work process. As a result, the volumetric (Q = 8·10–6 ÷ 2.5·10–4) and mass (W = 0.01 ÷ 0.3) concentration of a grain heap in different sections of the sieve mill of the combine harvester cleaning system. The experimental measurements of the airflow speed on the sieve mill’s surface for the existing structures of the cleaning system in modern grain harvesters were 3.75 ÷ 10.2 m/s. The data obtained will be used in the future to implement a mathematical model for a complete description of the technological process of a combine harvester cleaning system using methods based on two-phase flow mechanics.

Abstract-The authors of the paper present the results of theoretical research of the pulsed operating mode of linear electric sieve mill of grain cleaning machine MVR-2 (SU -0.1). It is shown that when using a linear electric drive in the grain cleaning machine in a pulsed mode, the productivity is increased by 20%.