World population has gradually increased and, as the resultof this increase, cultivation areas of grain group which is one of the basicrequirements of human have been expanded. As parallel with this expansion thegrain group should be stored for short and long term. Since the grain group isnot in pure situation within the place stored after harvesting, it should becleaned from foreing matters i.e. from grass, stones and sands. While screeningprocess made manually in sieves continued day after day in the past, thesystems which sieve tons of grain per hour have been developed thanks tostate-of- the-art technology nowadays. The name of this unit is pre-cleaningunit. Precleaning consists of 5 main components as of its general strcture:Drum case, drum, upper chamber. It has high resistance against corrosion. 10,9quality class bolts have been used as fastening element. Bolts ant nuts aredacromate plated and have high yield strength. St 37 quality black sheet hasbeen 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 beenapplied and 1 coat of paint has been applied over primer.
Product which enters hopper placed in upper chamber (aspiratör) through theelavator which is the silo equipment is transported to rotary durm within themain case While product is ﬂowing into drum, dusts and substances lighterthan air within product is drawn by radial fan mounted back of upper chamberand transmitted to cyclone mounted near the radial fan, It isensurded that the product ﬂows as horizontal by gving suitable inclinationangle to rotary drum so that product sieving process will be carried out inrotary drum and the product is passed out in rotary drum and the product ispassed through screens winded around rotary drum. Intermediate chamberswithin main case avoid materials which are separated after being passed throughscreens from mixing with the others and allow the materials to transferinto conveyor through bottom pouring compartments.