A combine destoner is an agricultural processing machine designed to separate stones, sand, metal particles, and other heavy impurities from grains such as rice, maize, wheat, and beans. It combines cleaning, grading, and destoning functions in a single unit, consisting of a feeding hopper, vibrating sieve deck, aspiration system, destoning chamber, and an electric motor drive. The machine utilizes differences in weight, size, and density to effectively remove unwanted materials while maintaining the quality of the grain.

In operation, grain is fed into the hopper and distributed evenly across the vibrating sieve surface. Airflow generated by the aspiration system lifts lighter impurities such as dust and chaff, while the vibrating deck separates heavier materials like stones and sand from the grain. The cleaned grain moves through the discharge outlet, while impurities are collected separately. This process improves grain quality, protects downstream processing equipment, and enhances the value of agricultural products by ensuring cleaner and safer output.