Crystal purification process and apparatus

Claim 1

IN A PROCESS FOR SEPARATING A COMPONENT FROM A LIQUID MULTICOMPONENT FEED MIXTURE WHICH COMPRISES INTRODUCING SAID FEED MIXTURE INTO A COOLING ZONE, COOLING SAID FEED MIXTURE IN SAID COOLING ZONE SO AS TO CRYSTALLIZE AT LEAST A PORTION OF ONE OF THE COMPONENTS OF SAID FEED MIXTURE, PASSING THE RESULTING SLURRY OF CRYSTALS IN MOTHER LIQUOR INTO A FILTERING ZONE, WITHDRAWING MOTHER LIQUOR FROM SAID FILTERING ZONE, PASSING THE RESULTING THICKENED CRYSTAL SLURRY INTO A PURIFICATION ZONE, CYCLICALLY COMPRESING SAID THICKENED CRYSTAL SLURRY SO AS TO SQUEEZE OUT MOTHER LIQUOR AND MOVE THE RESULTING COMPACT MASS OF CRYSTALS THROUGH SAID PURIFICATION ZONE INTO A MELTING ZONE, MELTING CRYSTALS IN SAID MELTING ZONE, PASSING A PORTION OF THE RESULTING MELT INTO SAID MOVING CRYSTALS SO AS TO DISPLACE OCCLUDED IMPURITIES THEREFROM, REMOVING MOTHER LIQUOR AND OCCLUDED IMPURITIES THEREFROM, REMOVING PORTION, WITH RESPECT TO CRYSTAL MOVEMENT, OF SAID PURIFICATION ZONE, AND RECOVERING A PURIFIED PRODUCT FROM SAID MELTING ZONE, THE IMPROVEMENT COMPRISING INTRODUCING SAID FEED MIXTURE INTO SAID FILTERING ZONE ONLY DURING THE MOTHER LIQUOR FROM SAID FILTERING ZONE ONLY DURING THE PERIOD WHEN COMPRESSION OF SAID CRYSTALS WITHIN SAID PURIFICATION ZONE IS TERMINATED AND TERMINATING FLOW OF FEED MIXTURE INTO SAID COOLING ZONE AND FLOW OF MOTHER LIQUOR FROM SAID FILTERING ZONE PRIOR TO THE BEGINNING OF EACH COMPRESSION CYCLE AND THROUGHOUT THE PERIOD WHEN COMPRESSION OF SAID CRYSTALS WITHIN SAID PURIFICATION ZONE IS TAKING PLACE.