Polygon Sieve is placed in front of the conveyor belt that carries sand to sand silos after turning from the shaker. The sand on the belt is discharged into the polygon sieve. The rotation movement of the polygon sieve ensures that the lumps are dispersed and crushed and discharged into the sand silos by passing through the sieves. The lumps, core pieces, casting burrs and other foreign materials that cannot pass through the Polygon Sieves are separated.