World population has gradually increased and, as the result of this increase, cultivation areas of grain group which is one of the basic requirements of human have been expanded. As parallel with this expansion the grain group should be stored for short and long term. Since the grain group is not in pure situation within the place stored after harvesting, it should be cleaned from foreing matters i.e. from grass, stones and sands. While screening process made manually in sieves continued day after day in the past, the systems which sieve tons of grain per hour have been developed thanks to state-of- the-art technology nowadays. The name of this unit is pre-cleaning unit. Precleaning consists of 5 main components as of its general strcture: Drum case, drum, upper chamber. It has high resistance against corrosion. 10,9 quality class bolts have been used as fastening element. Bolts ant nuts are dacromate plated and have high yield strength. St 37 quality black sheet has been used for cyclone and its parts have been joined by means of welding. In order to increase resistance against corrosion, 2 coats of primer have been applied and 1 coat of paint has been applied over primer.
Product which enters hopper placed in upper chamber (aspiratör) through the elavator which is the silo equipment is transported to rotary durm within the main case While product is flowing into drum, dusts and substances lighter than air within product is drawn by radial fan mounted back of upper chamber and transmitted to cyclone mounted near the radial fan, It is ensurded that the product flows as horizontal by gving suitable inclination angle to rotary drum so that product sieving process will be carried out in rotary drum and the product is passed out in rotary drum and the product is passed through screens winded around rotary drum. Intermediate chambers within main case avoid materials which are separated after being passed through screens from mixing with the others and allow the materials to transfer into conveyor through bottom pouring compartments.