Completeness of separation of impurities from grain heap by conveyor cleaning of grain harvester

The article considers one of the problems of high-performance conveyor cleaning of a grain harvester, which is insufficient completeness of separation of impurities. Field tests of a combine equipped with conveyor cleaning during harvesting of rye, barley and oats showed that in all three cases the completeness of separation of impurities from the grain heap increases until the heap layer thickness on the sieve reaches 3 cm. At the same time, when the heap layer thickness reaches 4-5 cm or more, grain losses begin to increase. It was found that the completeness of separation of impurities can be significantly increased provided that small straw particles up to 1-2 cm in length are removed. For this purpose, it is recommended to use sections of the conveyor sieve with smaller hole sizes than during testing or to improve the conditions of the air flow effect on the grain heap processed during cleaning. This will allow achieving a purity of the bunker heap of 95% or more. It has been experimentally established that 40% by weight of the impurities remaining in the bunker heap after processing on the conveyor cleaning are weed seeds, 88.19% of which are removed from the harvested field by the conveyor cleaning. Thus, a combine equipped with a conveyor cleaning allows, in parallel with its main task, to a large extent to solve a very important environmental problem.