Crystallization column

Claim 1

A crystallization column for counterflow of a crystal phase and a fluid phase of a mixture therein comprising: a cooler at one end of the column for crystallizing the mixture thereat; a heater at an opposite end of the column for melting crystals of the mixture thereat; a plurality of separating walls spaced along and disposed transversely across the column, and defining a plurality of mixing chambers longitudinally of the column for mixing of the mixture phases therein; one passageway in each separating wall communicating adjacent mixing chambers with each other for a counterflow of the mixture phases between said adjacent mixing chambers; at least one agitating device disposed in each mixing chamber for agitating and circulating the crystal phase and liquid phase of the mixture together in each mixing chamber; and a supplementary transporting means in said column for transporting the phases between said mixing chambers, said transporting means including a pair of piston rods relatively displaceable with respect to each other and passing through said passageways, and a first plurality of transverse radially extending porous piston plates connected to one of said piston rods, each of said porous pistons being in radially disposed relation to pass through one of said respective passageways in said separating walls, and a second plurality of transverse radially extending porous piston plates connected to the other of said piston rods wherein said piston rods are disposed in coaxial arrangement and wherein the outer piston rod is hollow and includes a plurality of elongated slots therein for passage of said plates connected to the inner piston rod, and whereby said piston rods are reciprocally movable in chronological sequence to open and close the passageways into a respective mixing chamber while transporting the phases between pairs of adjacent mixing chambers.