The gravity destoner is an indispensable processing machine for the flour mill. It mainly uses the  difference in the speed of suspension of wheat and stone in the air.

The screen surface of the gravity destoner vibrates in a specific direction. Due to the vibration, the material rapidly spreads on the screen surface. When the airflow speed is equal to the suspension speed of the wheat, the material on the screen will be automatically graded according to the size of the suspension speed. The stone with a large suspension speed is closely attached to the screen surface, and as the sieve surface is tilted upward, the stone is continuously moving upward and finally discharged out of the screen surface.