It efficiently removes a small amount of heavy material from a larger quantity of light material.The basic principle involves flowing dry granular material over an inclined, vibrating,screen covered deck. Air from pressure fans in the base is forced up through the deck. The uniform airflow vertically separates or stratifies the material, with lighter material in the upper strata flowing down the deck. Heavy particles such as stones,glass, metal etc., travel uphill and are discharged opposite the light material.The Fowler Oliver Destoner is a highly versatile, reliable machine with a proven design.