Justification of the Gravitational Seed Cleaning System Parameters

The author researched the gravitational method of separating a grain heap, in which cleaning from large and small impurities was carried out without energy consumption, with the gravity material fl ow in vertical cleaning columns along fi xed zigzag separating combs. (Research purpose) To study the gravity column operation for cleaning selection seeds and substantiate its design parameters. (Materials and methods) A prototype gravity column was developed. The author experimentally determined: the combs teeth diameter; column throughput; the possibility of a more complete separation of the seed fraction from the basic material; completeness of large impurities separation. He compared the work of the gravity column and the fl at rocking sieve. He assessed the combs jamming by the cleaned culture seeds. (Results and discussion) The author noted that on wheat cleaning at a productivity of 45.6 kilogram per hour, the yield of the "waste" fraction was 0.5 percent, a loss of 0.07 percent, and at a productivity of 227.8 kilogram per hour – 0.98 and 0.35 percent, which corresponded to the initial requirements for the main technological operations for post-harvest processing of selection seeds. (Conclusions) It was found that a gravity column for separating selection wheat seeds small impurities separated particles with high effi ciency if they diff ered from each other in thickness of at least 0.3 millimeter with a gap between the comb bars of 2.0 millimeter and a bar cross-section diameter of 0.9 millimeter. It was determined that high productivity – up to 150 kilogram per hour – was possible with a column cross-section with sides of 60 and 70 millimeter. The author revealed practically the same quality of material separation when separating small impurities using both a sieve and a gravity column.