Hydraulic classifier

Claim 1

APPARATUS FOR THE HYDRAULIC CLASSIFICATION TREATMENT OF A PULP CONTAINING A MIXTURE OF PARTICLE SIZES RANGING FROM FINE TO COARSE, TO EFFECT THE SEPARATION OF THE MIXTURE INTO A FRACTION OF FINES AND A FRACTION OF SANDS, SUCH FRACTIONS BEING DEFINED AS UNDERSIZE AND OVERSIZE PARTICLES RESPECTIVELY, WHICH APPARATUS COMPRISES A CLASSIFYING POOL HAVING SAID MIXTURE SUPPLIED THERETO IN A PORTION THEREOF AND SAID FRACTIONS DISCHARGED FROM ANOTHER PORTION THEREOF, SAID POOL BEING CONFINED WITHIN A TANK STRUCTURE COMPRISING A HORIZONTAL BOTTOM ELEMENT ADAPTED TO BE MOVED IN THE HORIZONTAL BOTTOM ELEMENT ADAPTED PROVIDED AND OPERATIVELY ASSOCIATED WITH SAID BOTTOM ELEMENT FOR CONTINUOUSLY REVERSING THE DIRECTION OF MOVEMENT IN THAT PLANE, AND WITH WATER SUPPLY MEANS PROVIDED FOR EMITTING AT THE BOTTOM HYDRAULIC AUXILIARY WATER AT A CONTROLLABLE RATE DISTRIBUTIVELY IN A MANNER WHEREBY THE WATER IN EFFECT RISES IN SUBSTANTIALLY UNIFORM DISTRIBUTION FROM THE BOTTOM AND WHEREBY THERE ARE ADAPTED TO BE FORMED AND MAINTAINED IN SAID POOL HORIZONTAL CLASSIFICATION ZONES COMPRISING SUBSTANTIALLY A COARSE SANDS ZONE OF OVERSIZE PARTICLES AT THE BOTTOM, A FINE ZONE OF UNDERSIZE PARTICLES AT THE TOP, AND AN INTERMEDIATE ZONE CONTAINING A MIXTURE OF UNDERSIZE AND OVERSIZE PARTICLES IN TEETER CONDITION, THERE BEING PROVIDED AN OVERFLOW WEIR FOR OVERFLOW DISCHARGE OF UNDERSIZE PARTICLES FROM SAID TOP ZONE OF THE POOL, UNDERFLOW SANDS OUTLET MEANS LEADING FROM THE BOTTOM OF THE POOL, THROTTLING MEANS SO ASSOCIATED WITH SAID OUTLET MEANS AS TO OPERATE DIRECTLY UNDER THE INFLUENCE OF GRAVITY OF THE PULP COLUMN IN THE POOL ABOVE, SAID THROTTLING MEANS BEING ADAPTED TO VARY THE THROUGH FLOW AREA OF THE OUTLET MEANS FOR THEREBY ADJUSTING THE PULP DENSITY IN THE POOL, AND A CONTROL SYSTEM COMPRISING A DENSITY RESPONSIVE PROBE DEVICE FUNCTIONALLY ASSOCIATED WITH THE POOL, AND AUTOMATIC RELAY DEVICES FUNCTIONALLY INTERCONNECTING SAID PROBE DEVICE AND SAID THROTTLING MEANS TO AUTOMATICALLY ADJUST THE THROUGHFLOW AREA THEREOF IN A MANNER TO MAINTAIN A PREDETERMINED PULP DENSITY IN THE POOL AND THEREBY A DESIRED SIZE SEPARATION AS BETWEEN THE OVERFLOW AND THE UNDERFLOW FRACTIONS.