The SPT type Dry Destoner is used to continuously remove stones and heavy fragments from a flow of granular product.

The feeding box, complete with band dosing, allows the granular product to enter the machine. This, uniformly distributed by the vibration of the inclined selection table, is brought into suspension by an ascending current, generated by an external aspirator which allows it to flow towards the lower part. The heaviest parts, influenced by the particular type of selection surface, head towards the discharge located in the upper part of the machine, while the lighter particles are sucked in by the upward current and, therefore, conveyed towards subsequent processes.