Gravity separation over a mesh belt conveyor

Abstract A new version of a gravity separator was developed to facilitate separation of large quantities of clods and stones from peanuts in the field. Separation takes place over an inclined mesh belt conveyor. Air passing through the conveyor lifts the lighter particles above the surface and they then flow downhill by gravity. The heavier particles remain in contact with the conveyor and move uphill. Mechanical vibrations used on conventional gravity separators as a means of conveying and agitating the material were eliminated to make the unit more suitable for use in the field. The unit is self-cleaning and cannot be blocked by vegetation debris from the field. The effect of the parameters was investigated for various mixtures of peanuts and clods and the relation between the slope and velocity of the mesh conveyor was determined. Field tests showed that the unit can separate mixtures containing a large percentage of clods (up to 99%) at a high pour rate. Therefore, it should be suitable for peanut-salvaging machines operating in medium or heavy soils. The unit also separates clods and stones from almonds in their green hulls.