Patent ID: 7699177

Claim:
A sand washing apparatus for separating organic material from a mixture comprising sand and organic material, the apparatus comprising: (a) a wash chamber in the shape of a funnel for accepting a mixture comprising sand and organic material, the chamber including a lower portion in the shape of a cylinder with an internal wall through which sand can descend in a downward direction and water can flow in an upward direction; (b) an agitator at least some portion of which is positioned within the cylinder, which is configured so that its rotation creates a lifting action tending to force at least a portion of sand descending through or already present in the cylinder to flow in an upward direction; (c) a collection chamber positioned below the wash chamber for collecting washed sand that has descended past the cylinder; and (d) a conveyor configured to transport sand away from the collection chamber, wherein the agitator comprises a screw having two or more flights, and a means for allowing at least a portion of sand to flow in the downward direction in the wash chamber within a perimeter of the agitator.