Influence of the Grid Inclination Angle on the Efficiency of Preliminary Separation of the Combed Heap

Introduction. A highly topical scientific and practical task is to justify the choice of the most advanced variant of the device for pre-separating the combed heap and to optimize its design. Aim of the Study. The study is aimed at testing the effect of the grid inclination angle on the effectiveness of pre-separating the combed heap. Materials and Methods. It is possible to minimize the separated grain flow into the threshing machine either by means of a feeder house grid bottom or by means of a horizontal separating device, located directly in front of the threshing drum. To select the optimal design of the separation device, there was planned and conducted a laboratory experiment. The study was carried out in two stages. In the first series of experiments, the elevator body was installed horizontally, and in the second series – at an angle of 45° to the horizon. The width of the grid bottom openings had four variations (6, 8, 10 and 12 mm), and the speed of the scraper conveyor was 3 m/s. A combed heap of the winter wheat variety Moskovskaya 56 was selected as the study object. The grain moisture was 12%. Results.According to the results of laboratory studies, it was found that with an increase in the width of the grid surface openings, the intensity of separating grain increases. The maximum device throughput (90%) corresponds to the horizontal position of the grid bottom of the experimental installation and the width of the openings b = 12 mm. Extrapolation of the separated grain decreasing graph indicates that to ensure complete separation of grain, the length of the separating grid should be at least L = 0.9 m. Discussion and Conclusion. The use of a horizontal separating grid allows increasing the device separation efficiency and reducing its metal content by 14–16%.