Apparatus for regenerating foundry sand

An apparatus for regenerating foundry sand, comprising:

• means forming an upright chamber having an axis and formed with an annular peripheral wall and a bottom;
• at least one abrading horizontal tool mounted in said chamber at a short distance from said bottom and rotatable about said axis;
• means for feeding foundry sand downwardly in a generally vertical central stream in said chamber to said bottom, said tool displacing the sand toward said peripheral wall to form an annular column of said foundry sand rising exclusively of an orbit of said tool;
• supply means at spaced locations in said peripheral wall and close to said bottom for supplying air along generally upward paths and exclusively outwardly of said orbit, said column being raised in said chamber upon displacing of said sand by said tool and upon by the air supplied to a level in an upper part of said chamber and having a plurality of zones of less dense fluidized sand along said paths at said spaced locations and zones with more dense sand between said locations, said foundry sand in said zones of less dense sand upon reaching said level being displaced radially inwardly toward said axis to redescend along said central stream downwardly to said abrading tool;
• and
• means for removing a dust-laden air above said level of said foundry sand in said chamber.