Hydraulic classification method and apparatus

Claim 1

A CLASSIFIER FOR SEPARATING PARTICLES OF DIFFERENT SIZES COMPRISING IN COMBINATION, A TANK ARRANGED TO CONTAIN A POOL OF PULP OF SAID PARTICLES, PULP ENGAGING AND MOVING MECHANISM OPERABLE WITHIN SAID TANK AND INCLUDING A SERIES OF PULP CONFINING COMPARTMENTS OF PREDETERMINED VOLUME ARRANGED TO ENGAGE AND SEGREGATE SUCCESSIVE QUANTITIES OF PULP, AND MEANS OPERABLE TO MOVE SAID COMPARTMENTS UPWARD ALONG A GENERALLY INCLINED PATH EXTENDING FROM BELOW THE POOL SURFACE TO A SANDS OUTLET ABOVE SAID POOL SURFACE, SAID COMPARTMENTS EACH HAVING AN OPENING THEREIN SUBSTANTIALLY BELOW THE TOP OF THE COMPARTMENT AND OPERABLE TO PERMIT DECANTING OF FINES AND LIQUID FROM THE UPPER PORTIONS OF SAID CONFINED QUANTITIES THROUGH SAID OPENING THEREIN AND SAID COMPARTMENTS OTHERWISE BEING IMPERVIOUS ABOVE THE LEVEL IN WHICH SAID OPENING IS DISPOSED IN EACH COMPARTMENT EXCEPT FOR INCIDENTAL LEAKAGE, THEREBY SHIELDING THE CONFINED PULP WITHIN SAID COMPARTMENTS FROM CONTRACT BY FINES AND LIQUID DISCHARGED FROM PRECEDING QUANTITIES.