The Four Deck Seed Grader is a single-chamber calibration machine designed to sort cereals, pulses, oilseeds and nuts—which have undergone preliminary cleaning or do not require cleaning—solely on the basis of their size. It separates the product into four different sizes with millimetre precision, whilst also successfully removing broken grains. In industrial production lines, it is typically positioned at the outlet (lower section) of colour sorting (photosorter) machines, serving as the final quality control stage.

Working Principle: The machine, which operates entirely mechanically and focuses on dimensional calibration without an air suction or aspiration system, functions as follows:

• Homogeneous Feeding via the Distributor Hopper: The raw material to be screened is first transferred to an integrated product distributor hopper. This hopper ensures that the product is discharged onto the screening trays at a balanced and uniform flow rate.
• Vibrating Screening Mechanism: The product transferred onto the screen is spread evenly across the screen surface thanks to the controlled vibrating (vibration) movement applied to the body. The four independent screening trays, which feature an additional screening layer compared to three-tray models, enhance dimensional separation accuracy and calibration precision.
• 4 Different Size Separation and Broken Particle Control: The raw material, which is progressively sieved through the mesh openings of the screens, is sorted by size to produce four distinct final product grades. During this process, broken particles within the product are completely separated from the main mass and directed to independent discharge chutes. The system can be optionally manufactured with a fixed or mobile (wheeled/portable) chassis design, depending on the facility’s layout and mobility requirements.

Products Processed and Graded: It is safely used for the precise commercial grading of all dry-seeded agricultural products, including soya beans, chickpeas, beans, broad beans, lupins, sesame, lentils, wheat, rice, sunflower seeds and cumin.