Theory of threshing oilseeds from sunflower heads using an adapter auger

The paper provides a rationale for the refusal of pre-harvest desiccation of sunflower crops by some producers and the shift of the harvest time, which leads to the natural drying of the heads and a decrease in the moisture content of the oilseeds by 6–9 %. The main technological parameters and quantities affecting the process of threshing the oilseeds by the adapter's auger are highlighted. The paper mathematically examines the interaction of the flights with the cut down heads and establishes the forces acting on them as they move towards the chain-plate conveyor window of the inclined chamber. The decrease in the adhesion force of oilseeds to the receptacle and to each other with a decrease in humidity is substantiated. Analytical expressions for the probability of threshing of heads with an increase in the number of oilseeds with a critical (decreased) adhesion force to the receptacle, and an expression for determining the number of threshed oilseeds with a humidity of 6–9 %, have been obtained. A comparative analysis of the obtained analytical dependence with the results of the production evaluation of the NASH-873 adapter, carried out at a similar moisture content, is provided. Theoretically, the maximum amount of oilseed threshing by the flights was determined to be 25.00 % of the biological yield at a minimum moisture content of 6 %, and according to the analytical expression at moisture contents of 7; 8; 9, % the extraction would be 18.75 %, 16.67 %, and 15.00 %, respectively.