Development of electrostatic separator of foreign objects in dried foods

The number of occurrences of foreign objects in food is becoming less frequent. However, it is very difficult to remove small foreign objects such as hair and soft plastics in food. In this paper, the results of an experimental study of the performance of a new electrostatic separator of small foreign objects in dried food are presented. The separator consists of an inclined rotating drum, which is grounded, a cylindrical electrode fixed at the center of the drum and a suction device. The principle of the separation is based on the difference in the charge per unit mass of the dried food and foreign objects. Separation tests were performed on two types of mixtures. The effects of operating parameters, such as the applied voltage and the angular speed of the drum, on the separation efficiency were examined. In the separation of a mixture of plastic fragments and dried lettuce, the recovery rate of the lettuce was greater than 96% for a purity of 100%. In the separation of a mixture of hairs and dried lettuce, the recovery rate of the lettuce was greater than 94% for a purity of 100%.