Investigation on the Separation of Wheat Bulk Impurities with Gravity Separator Table

Presence of foreign materials with the product is one of the important problems of wheat production. The economic value of the produced wheat and the degree of purity of the produced seeds increases with the separation of wheat mass impurities. Hence, in this research, a gravity separator table was used to remove impurities from wheat bulk. The machine has adjusting five parameters of air velocity, frequency of oscillation, amplitude of oscillation, longitudinal slope and latitudinal slope of the table. The effect of these parameters was studied to achieve maximum impurity separation from wheat bulk. Statistical analysis was performed in two factorial experiments based on completely randomized design. In the first experiment, the effects of three parameters of longitudinal slope, latitudinal slope and frequency of oscillation of the table were investigated and in the second experiment the effect of two other parameters was investigated. Also, using dimensional analysis, a dimensionless number parameter was obtained which was effective in evaluating the effect and reducing the number of parameters. The results showed that the maximum separation of impurities from wheat bulk was 87.03% at longitudinal slope of 2.5 °, latitudinal slope of 1.5 °, frequency of oscillation of 395 cycles per minute, amplitude of oscillation of 5 mm and air velocity of 6.75 m/s,. Also, with increasing longitudinal slope from 2.5 ° to 4.5 °, latitudinal slope from 0.75 °  to 2.5 ° (in most cases) and the amplitude of oscillation of the table from 5 to 7 mm, the separation of impurities was reduced and with increasing the air velocity from 5.25 to 6.75 m/s the separation of impurities was increased.