Sieves called grizer sieves produced by Varlık Makina are generally used for separating coarse grain products into two or more groups as preferred.
Prescreening sieves are available in two types; as vibratory and motor driven.
The purpose of prescreening is to separate materials that are greatly different in size from the system. Humid or wet products (sand, gravel) and different products are also screened out with this sieve. Sieve sizes are determined according to capacity. Settings are carried out with vibration weights for efficiency.
Feeding of the sieve is carried out with vibration chutes, screw conveyors, air locks, or conveyor belts.