The influence of the composition of the combed grain heap on the preliminary separation of loose grain

BACKGROUND: The paper reviews the state of the problem of grain harvesting by the method of combing plants on the root. Attention is focused on the potential economic efficiency of the method and on the scientific and technological problems hindering its widespread implementation. In particular, in order to reduce the degree of crushing of loose grain, it is necessary to separate it preliminary and prevent it from entering the threshing device. It is proposed to remove grain directly on the lattice bottom of the inclined chamber of the combine harvester. The scientific hypothesis of the study suggests that in order to improve separation, it is advisable to remove a significant part of light impurities from the pile directly preliminary in the body of the combing adapter. AIM: Evaluation of the efficiency of separation of loose grain by removing a significant part of light impurities from the combed pile before it enters the inclined chamber. METHODS: To confirm the hypothesis, the experiment was conducted in which a combed grain pile of wheat of the «Moskovskaya 56» variety of different component composition was fed to a lattice surface equipped with a scraper conveyor. The weight content of the grain varied from 70 to 100%. The experiment took into account the proportion of loose grain that passed through the holes of the grate at its length of 920 mm and the width of the holes of 12 mm. It ranged from 65 to 80% as the content of loose grain in the pile increased. RESULTS: According to the study results, it was found that the passage of loose grain through the openings of the lattice bottom varies between 65-80%. At the same time, a decrease in the mass fraction of loose grain in the pile reduces its passage through the openings of the lattice surface by 15%. CONCLUSION: Preliminary removal of light impurities from the combed grain pile, comparable in size to loose grain, can be carried out by using an inertial separation system. Reducing the proportion of light impurities in the pile entering the combine harvester cleaning system makes it possible to significantly increase the efficiency of its operation.