Home Product Cleaning & Conditioning Drumsieve DRUM SIEVE Rotating Drum Screening. Incoming wheat passes through a rotating drum fitted with specially designed sieves for preliminary cleaning. Removal of Oversized Impurities. Separates straw, husk and other large foreign materials from the incoming wheat. Screening of Smaller Impurities. Separates dust and other undersized unwanted particles through the sieving process. Separate Impurity Discharge. Oversized and undersized impurities are separated and discharged during screening. Clean Wheat for Further Processing. Pre-cleaned wheat moves forward to the conditioning and milling stages.