Apparatus and method for separating particles

Claim 1

A METHOD OF CLASSIFYING A MIXTURE OF PARTICLES INTO A PLURALITY OF DISCRETE FRACTIONS HAVING DIFFERENT VELOCITIES OF SEDIMENTATION COMPRISING MAINTAINING A VERTICAL COLUMN OF ELECTROFLUID, APPLYING ELECTRIC FIELDS OF DIFFERING MAGNITUDES AT A PLURALITY OF ZONES ALONG THE LENGTH OF SAID COLUMN, INTRODUCING A MIXTURE OF PARTICLES HAVING A DENSITY DIFFERING FROM THAT OF SAID ELECTROFLUID AT ONE END OF SAID COLUMN AND REMOVING SEGMENTS OF SAID COLUMN CONTAINING DISCRETE FRACTIONS OF SAID PARTICLES FROM THE OTHER END OF SAID COLUMN, FLOWING THE ELECTROFLUID IN A DIRECTION COUNTERCURRENT TO THE DIRECTION OF PARTICLE SEDIMENTATION, THE APPLIED FIELDS BEING OF LEAST MAGNITUDE AT THE ZONE AT THE END OF SAID COLUMN WHERE THE PARTICLES ARE INTRODUCED, AND INCREASING IN MAGNITUDE ALONG THE LENGTH OF THE COLUMN, THE MAGNITUDE OF THE FIELD AT EACH ZONE BEING ADJUSTED SO THAT THE SEDIMENTATION RATE OF ONE SAID FRACTION IN SAID ZONE EQUALS THE RATE OF FLOW OF SAID ELECTROFLUID, AND REMOVING FROM THE ZONES ELECTROFLUID CONTAINING SAID DISCRETE FRACTIONS.