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To improve the quality and effectiveness of pre-sowing treatment of seeds of grain crops, a hypothesis was put forward on the possibility of using the air flow to continuously perform a set of technological operations in the process of dressing. The proposed approach is implemented in a unrivalled pneumomechanical deresser, in the processing chamber of which a multiphase flow of dispersed mixture “air-seeds-droplet” is formed. For the theoretical justification of the main parameters of the processing process, a mathematical model of the movement of seeds and fine droplets of the working fluid was developed and numerically solved taking into account the decrease in their concentration along the length of the working chamber. As a result, it was found that the speeds of seeds and drops of different sizes as they move in the processing chamber naturally increase, and the concentration of drops decreases asymptotically. It was revealed that to ensure high quality processing at the entrance to the processing chamber, the seeds should move in suspension with the speed of the corresponding droplet speed of the working fluid. The minimum path length of the “air-seed-droplet” mixture is substantiated, where the maximum decrease in the concentration of drops occurs due to the adhesion of seeds suspended in the air flow to the surface. The results obtained are important for optimizing the length of the processing chamber, substantiating the modes and parameters of the movement of air, grain and drops, at which full coverage of seeds with a minimum flow rate of the working fluid is achieved. In the long term, the research results will serve as the basis for optimizing the design and technological parameters of pneumomechanical dressers, which ensure high quality and efficiency of pre-sowing treatment of seeds of grain crops.

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In agricultural machines, seeds are injured, which damages the crop: conditions are created for the development of harmful organisms during storage, field germination decreases. The relevance of the study of seed injury is caused by the need to improve technologies and designs of agricultural machines that reduce or eliminate seed damage. Currently, there are no studies to assess the change in the amount of grain injury over the entire production cycle. The purpose of this work is to establish the regularity of changes in grain injury in agricultural machines by stages of technology. On the basis of a specially developed end-to-end technique, the injury of wheat seeds of different varieties, differing in categories according to GOST R 52325-2005 “Varietal and sowing qualities of seeds of grain and leguminous plants” and their reproductive anatomical parts - endosperm, embryo, tuft, was experimentally investigated. A new concept of “degree of injury” is introduced and a formula for its calculation is proposed, which allows quantifying the amount of injury to grain seeds and their anatomical parts. It was revealed that the greatest injury occurs in combine harvesters, where the degree of injury is 36.1 ...44.2%. It is established that at each stage, regardless of the technology used, the complex of machines and equipment, the number of injured seeds increases: during post-harvest processing, taking into account the separation of part of the injured grains, which cannot be tracked by 0.1 ...3.3%; when removing from storage and final processing of seed material before etching by 5.0... 10.4%; in a etching machine with screw loading and unloading devices by 7.3 %; in a screw-type seed loader by 4.9%; in seeding machines of individual dosing and gravity feeding of seeds into coulters by 2.9...3.2%, and group dosing with pneumatic transport of the sown material by 4.4...4.7%. In the end, when entering the soil, the degree of injury to wheat seeds is in the range of 57.0 ... 61.4%. Of these, with injury to the endosperm – 51.7...58.4%, germ – 1.9...2.2%, tuft – 1.1…1.8%. The lowest values were obtained when using bags for loading sowing machines, instead of a screw loader of seeders.