The paper provides rationale for safe modes and methods for calculating a two-stage drying technology with partial recirculation of grain, in which the grain is under-dried by 2…3% to the standard humidity in a grain dryer, and the hot grain is cooled by active ventilation with outside air, while drying it to the standard humidity. The safe mode of two-stage drying in S-40 provides for partial recirculation of grain with moisture removal close to the standard, and the moisture content of the recirculated mixture not exceeding 18%. The recirculation coeffi cient calculated based on this condition is used to determine the temperature of the recirculating grain mixture, taking into account the reversible component in the shaft dryer. The minimized recirculation ratio provides for the permissible unevenness in drying and minimal fracturing. The recirculation drying process was analyzed according to the standard method, but with the adjusted values of moisture removal and temperature of the grain mixture. Economic tests of the S-40 dryer were carried out using a two-stage technology on corn grain. It has been experimentally established that the S-40 dryer with a recirculation coeffi cient of 2 and a moisture pick-up of 4% per cycle when drying corn grain with a moisture content of 23.5 to 15.6%, at a drying agent temperature of 95°C, provides a throughput of 10 t/h (without refrigeration). Cooling was carried out in the warehouse. No signifi cant changes in the quality of dried and cooled grain have been established: the starch content and fracturing practically did not change; the unevenness of the dried seeds did not exceed the original requirements. The expediency of using the S-40 direct-fl ow dryer in the recirculation mode has been experimentally established.

The paper provides information on the causes of failures in agricultural machinery engines, provides a brief overview of the ways to identify malfunctions using digital technologies introduced into the diagnostic process, and ways to eliminate them. The introduction of forecasting as a separate stage in the process of diagnosing agricultural machinery using machine learning technologies in the form of neural networks is analyzed. The results of the study reflect that the neural network, analyzing a huge amount of data obtained during remote diagnostics, is able to more accurately predict failures in agricultural machinery engines.

Two-stage drying is widely used in agriculture in Russia and abroad when grain is under-dried to condition humidity by several percent and left to dry by atmospheric air, thereby saving costs of heat. When using this method, there are questions about determining the minimum air velocity in the layer, the calculation of retention time before and during the ventilating process itself. For different thicknesses of the material layer, the retention time varies greatly - from 6 h to 24 h. This is due to the fact that the duration is usually set empirically by the increased or decreased moisture content during the process. Cooling duration is calculated from the recommended normative specific air supply to the bulk and its consumption per ton of cooled grain, which often leads to overestimated cooling duration. Therefore, the purpose of this work is to substantiate and calculate the permissible specific air supply, as well as the duration of tempering and cooling of grain. Minimum specific air supply during cooling of heated grain depends on the layer thickness, the coefficient of moisture evaporation and the logarithm of the difference between the relative humidity of moisture vapor on the surface of grain and air. The minimum duration of tempering of heated grain is caused by moistening its outer surface and depends on the coefficient of moisture diffusion, the radius of the grain, the thickness of the shell and the logarithm of the difference between the current and equilibrium moisture content. The duration of cooling of the embankment can be calculated according to the dependencies for drying grain at the actual values of air and embankment parameters. Economic studies have shown the admissibility of using the obtained dependencies for calculating the main parameters of the process without reducing the quality of grain.

The article presents the results of studies of the efficiency of drying grain by reducing the specific energy consumption, allowing improving the quality of the resulting products and in-creasing the productivity of drying. The achievement of the results was a mathematical model, which was based on the general laws of heat and mass transfer, reflecting the specific features of the research. It is not that most continuous dryers for bulk materials have several zones with different parameters of the input and output-drying substance, which carry out drying under variable dynamic conditions.

The main condition for feed preparation is to ensure the high quality of the finished product. At the sametime, it is necessary to increase the efficiency and durability of the feed chopper by optimizing its design parameters,taking into account the physical and mechanical properties of the processed material. The authors studied the technologicalprinciple of crushing root and tuber crops. The paper considers the operation of an industrial rotary feed chopper whenprocessing beets and carrots. The experiment planning method is applied. The strength characteristics of the grinderelements were checked during design (selection of the shape and sharpening angle of knives) and verificationcalculations for strength (assessment of the strength characteristics of knives). The authors show the influence of the main geometric parameters of the working implement of the grinder – the knife inclination and the sharpeningangle of the knives – on the preparation of high-quality feed. It was revealed that the sharpening angle of the grinderknives should be calculated depending on the friction coefficient of the initial material against the grinder body, aswell as the type and properties of the supplied material. Based on the data obtained during the laboratory experimentand simulation modeling, in order to achieve greater versatility with the feed chopper, a combined shape of the cuttingedges of the knives was chosen – that with a straight and serrated cutting edge of the chopper. Samples of cutting edgesat 30x magnification, obtained using an instrumental microscope MMI-2, showed that the optimal shape of the knifeis a wedge with a double escapement