Fractional crystallization process and apparatus

Claim 1

FRACTIONAL CYSTALLIZATION APPARATUS COMPRISING, IN COMBINATION, AN ELONGATED, CLOSED PURIFICATION COLUMN; A HEATING MEANS OPERATIVELY CONNECTED TO ONE END OF SAID COLUMN; MEANS FOR WITHDRAWING A PURIFIED PRODUCT FROM SAID END OF SAID COLUMN; INTERNAL FILTERING MEANS IN AN INTERMEDIATE PORTION OF SAID COLUMN; A CRYSTAL MOVER INEANS, THE OPPOSITE END OF SAID COLUMN FROM SAID HEATING MEANS, SAID CRYSTAL MOVER BEING ADAPTED TO MOVE WITHIN SAID COLUMN AT LEAST UP TO SAID FILTERING MEANS; A SUBSTANTIALLY CYLINDRICAL MEMBER CLOSED AT ONE END AND HAVING ITS OTHER END CONNECTED TO SAID COLUMN UPSTREAM CRYSTALWISE OF SAID FILTERING MEANS; A SUBSTANTAILLY CYLINDRICAL FILTER MEDIUM DISPOSED WITHIN AND SPACED APART FROM SAID CYLINDRICAL MEMBER SO AS TO FORM AN ANNULAR SPACE THEREBETWEEN; A CRYSTAL SLURRY INLET MEANS CONNECTED TO SAID CYLINDRICAL MEMBER AND IN COMMUNICATION WITH THE INTERIOR OF SAID FILTER MEDIUM; LIQUID OUTLET MEANS CONNECTED TO SAID CYLINDRICAL MEMBER AND IN COMMUNICATION WITH SAID ANNULAR SPACE; MEANS FOR MOVING CRYSTALS LONGITUDINALLY WITHIN SAID FILTER MEDIUM AND INTO SAID PURIFICATION COLUMN; A CYLINDER CLOSED AT ONE END AND HAVING ITS OTHER END ATTACHED TO AN INTERMEDIATE PORTION OF SAID CRYLINDRICAL MEMBER; A PISTON DISPOSED WITHIN SAID CYLINDER, SAID PISTON BEING ADAPTED TO FORCE LIQUID FROM SAID ANNULAR SPACE THROUGH SAID FILTER MEDIUM; AND MEANS FOR SYNCHRONIZING THE MOVEMENT OF SAID PISTON WITH SAID CRYSTAL MOVER SO THAT SAID END OF SAID SUBSTANTIALLY CYLINDRICAL MEMBER CONNECTED TO SAID COLUMN IS CLOSED BY SAID CRYSTAL MOVER WHEN SAID PISTON IS FORCING LIQUID FROM SAID ANNULAR SPACE THROUGH SAID FILTER MEDIUM.