Grain Grader Manufacturers

Grain graders — types and applications

Grain graders (also called grain classifiers, separators, or sifters) separate grain into size and length classes for commercial grading, cleaning, or milling preparation. The main types include: rotary drum screens (a rotating perforated cylinder with multiple screen sections — large foreign material is removed from the outside; undersized grain falls through to a bottom collection; on-size grain passes through); flat oscillating screens (vibratory or gyratory screens with multiple screen decks — separate grain into fractions by width and thickness); indent cylinders or trieur cylinders (a rotating cylinder with small indentations or cells on the inner surface — short grains or seeds are carried in the indentations and discharged at the top; long grains or stalks pass through without being lifted — used to separate short weed seeds from wheat grain, or broken grain from whole grain in rice milling); and optical colour sorters (separate grain by colour and surface defect rather than by size — standard in premium rice milling and seed cleaning). Grain graders are used both in the pre-cleaning section of grain mills (to separate contaminants from grain before milling) and in post-milling or post-processing quality grading (to produce uniform, graded products for export or premium markets).