Synchronizing the Interaction Between the Metering Unit and the Mung Bean Sorting Sieve

Harvested mung bean grain contains a significant amount of extraneous impurities; including small and unripe grains. Therefore; the grain must be cleaned and sorted by size. The developed cylindrical sorting sieve with a screw distributor inside must be equipped with a metering unit to ensure that the raw material from the hopper is fed into the sorting process in accordance with the sieve’s operating mode. (Research purpose) To develop theoretical foundations for synchronizing the operating modes of a paddle-type metering unit and a sorting sieve for removing weed impurities and fractionating harvested mung bean grains. (Materials and methods) The feeding of bulk material by the metering unit is always batchwise. The screw distributor installed inside the sorting sieve also operates in a batch mode. Based on this principle; their synchronization is necessary. (Results and discussion) The main performance characteristics of the paddle-type metering unit are throughput capacity and fill factor. It was established that the fill factor of the metering unit can be considered equal to its maximum possible value; which is determined by its design parameters; since the sorting sieve operates at a low rotational speed. For synchronised operation of the metering unit and the sorting sieve; their throughput capacities must be equal; and their rotational speeds must be multiples of each other. A high multiplicity ratio of the metering unit’s rotational speed to that of the cylindrical sieve sorter with a screw distributor requires an increase in the metering unit’s speed; which leads to higher energy consumption and potential damage to the dosed material. As the number of blades in the metering unit increases; the required rotational speed decreases. A metering unit rotational speed of 6 rpm corresponds to an outer radius of 59.6 mm; while a speed of 4 rpm corresponds to a radius of 71.9 mm. In the first case; for synchronization of the metering unit with the sorting sieve; the multiplicity ratio must be 3; and in the second case; it must be 2. The actual values of the outer radius of the metering unit will be determined based on the results of experimental studies to ensure proper synchronization. (Conclusions) For efficient cleaning and sorting of mung bean grains harvested by a combine; the cylindrical sorting sieve must be equipped with a metering unit that delivers the raw material from the hopper in accordance with the sieve’s operating mode. The batch operation of both the sorting sieve with an internal screw distributor and the blade-type metering unit enables their synchronization. To reduce energy consumption and minimize grain damage; lower multiplicity ratios between the metering unit and the cylindrical sorting sieve should be maintained.