development and evaluation of tribo- aero- electrostatic for impurity separation from plant seeds (flixweed)

seed purification is one of the important agricultural processes to obtain high quality seeds. using modern technologies help producers to do this process with higher precision and accuracy. in order to separate seed impurities, a separation machine called tribo-aero-electrostatic separator was designed. the machine was evaluated by separating impurities of flixweed (descuriania sophia). primary laboratory tests showed its high efficiency. initial materials were separated in tribo-charge part by gravity and electrostatic force produced by high dc voltage. to evaluate the system performance statistically, the effects of voltage, distance between the tribo-charge electrodes and electrode angle of separation unit were investigated with three replications on the weight of separation boxes. this experiment was performed as a crd- based factorial design and the data were analyzed using sas software. the results indicated that the effects of all factors on the weight of purified seed and impurities in collecting boxes were significant at 1% confidence level. in addition, interactions of almost all factors in collecting boxes were significant at 1% level. by increasing applied voltage and electrode angle, and decreasing the electrode distance, best seed purity with the highest weight was obtained in the pure seed box.