A destoner machine is used to remove heavier contaminants or debris from a product stream or flow. Generally, it removes a small percentage from the flow, but it can be large items including: stones, glass, metals or other heavy items. Using a fluidized bed of air and a vibrating deck to move the heavier materials uphill is what the machine does to separate the products into light and heavy materials. In the conditioning process, the destoner can be used ahead of a gravity separator or behind it. http://www.cnfood-mech.com/grain-selecting-machine/grain-destoners.html