Fractional crystallization apparatus

Claim 1

CRYSTAL PURIFICATION APPARATUS COMPRISING, IN COMBINATION, AN ELONGATED PURIFICATION COLUMN, MEANS FOR MELTING CRYSTALS IN ONE END PORTION OF SAID COLUMN AND CONDUIT MEANS FOR WITHDRAWING PRODUCT THEREFROM, MEANS FOR INTRODUCING CRYSTALS INTO AN INTERMEDIATE PORTION OF SAID COLUMN, AND ELONGATED, LONGITUDINAL SLOT IN THE WALL OF SAID COLUMN ABOVE SAID SEALING MEANS HEREINAFTER RECITED, FILTERING MEANS IN SAID COLUMN BETWEEN SAID CRYSTAL MELTING MEANS AND SAID CRYSTAL INTRODUCTION MEANS, A RECIPROCABLE PISTON IN THE OPPOSITE END PORTION OF SAID COLUMN FROM SAID CRYSTAL MELTING MEANS, AID PISTON COMPRISING AN ELONGATED, HOLLOW CYLINDRICAL MEMBER WITH ITS END TOWARD SAID MELTING MEANS BEING OPEN AND ITS OPPOSITE END BEING CLOSED, FILTER MEDIUM POSITIONED IN SAID OPEN END OF SAID CYLINDRICAL MEMBER, A PLATE MEMBER POSITIONED IN AND ATTACHED TO THE WALLS OF SAID CYLINDRICAL MEMBER ABOVE SAID FILTER MEDIUM, AND A CONDUIT ATTACHED TO SAID PLATE MEMBER AND IN COMMUNICATION WITH THE SPACE FORMED BETWEEN SAID PLATE MEMBER AND SAID FILTER MEMBER, SAID CONDUIT EXTENDING FROM SAID PLATE MEMBER THROUGH SAID CLOSED END OF SAID CYLINDRICAL MEMBER AND EXTERIORLY OF SAID COLUMN THROUGH SAID LONGITUDINAL SLOT THEREIN, SEALING MEANS IN SAID COLUMN BETWEEN THE INNER WALL OF SAID COLUMN AND THE OUTER WALL OF SAID PISTON, A RING MEMBER IN CONTACT WITH AND ENCOMPASSING THE WALLS OF SAID CYLINDRICAL MEMBER, THE END OF SAID RING MEMBER TOWARD SAID CLOSED END OF SAID CYLINDRICAL MEMBER BEING IN THE FORM, OF A KNIFE EDGE ADAPTED TO SCRAPE THE WALLS OF SAID CYLINDRICAL MEMBER UPON MOVEMENT OF SAID CYLINDRICAL MEMBER TOWARD SAID FILTERING MEANS, SAID RING MEMBER BEING POSITIONED IN AN ENLARGED PORTION OF SAID COLUMN BETWEEN SAID SEALING MEANS AND SAID OPPOSITE END OF SAID COLUMN.