Comparative Analysis of Cleaning Units of Hillside Combine Harvester
Harvesting of grain crops on sloped fields with combine harvesters of the standard configuration is characterized by excessive grain losses, most of which fall on a cleaning unit. Cleaning units for a hillside combine harvester, developed by the group of authors, differ in qualitative characteristics, design, and weight. The purpose of the research was to compare cleaning units and select the most competitive of them. The investigation was carried out under laboratory conditions at the lateral tilt of the laboratory setup at the 8-degree angle using a thrashed heap of wheat with 10-12 % moisture content and 30 % of straw impurity content. The following schemes were studied: cleaning unit with a spiral screen separator; cleaning unit with a two-section upper sieve; cleaning unit with a self-installing upper sieve; combined cleaning unit with both spiral screen separator and self-installing upper sieve; cleaning unit with grain heap spreader on the upper sieve; cleaning unit with adapter for slopes. The comparison was carried out with a cleaning unit of a third-class combine harvester. Various schemes of cleaning units were assessed by means of the integrated coefficient of competitiveness of the machine, calculated on the basis of the flow rate of the grain heap with grain losses of 0.5 % and the calculated weight of the combine harvester. The following schemes of cleaning units were identified as the most competitive: cleaning unit with grain heap spreader on the upper sieve (the supposed integral combine harvester competitiveness coefficient is 1.61), cleaning unit with the self-installing upper sieve (1.66), combined cleaning unit with both spiral screen separator and self-installing upper sieve (1.75), and cleaning unit with the adapter for slopes (1.76).