Сепарация очесанного зернового вороха на решетчатом днище наклонной камеры комбайна

Abstract

Using the grates of a combine feederhouse and directing the grain heap for cleaning, bypassing the threshing unit, we can reduce both the energy intensity of harvesting and the degree of grain crushing. The study purpose is to compare two variants of the combine feederhouse grates: with longitudinal holes of a finite length and transverse bars between them and with through holes without transverse bars. For a preliminary assessment, a theoretical model of the separation process is proposed, which includes the slipping of combed heap layers moved by a conveyor scraper into the hole at the angle of repose. Previously, it was assumed that upon contacting with a transverse bar, the corresponding heap layer completely stops slipping and the process resumes only after overcoming the edge of the next hole. As a result, the separation rate should significantly decrease. The upgraded version of the model takes into account the inertia effect on the sliding upper heap layer, which is activated by the friction force of its lower part acting along the bar surface. As a result of the total effect of the rolling force and the inertia force, the flow direction of the upper layer components changes to become nearly horizontal, as a result of which 50 to 60% of the layer slides into the next hole without stopping. According to the theoretical model, the separation of combed grain heap should be reduced by 4 to 5% if there are 120 mm long bars between the longitudinal holes and the total length of the separating part of the grates surface is 800 mm. As a result of a laboratory experiment on the Moskovskaya 56 wheat variety, the separation of a combed grain heap decreased by 4.6% due to transverse bars, which confirmed the adequacy of the theoretical hypothesis.