Device for substance separation from a liquid mixture by crystallization, and method

An endless belt separator device for separating a substance from a liquid mixture by crystallization,

• said device comprising
• an elongated endless band or belt (12) defining an upper run (17) and a lower, or return run, and wherein the surfaces of said endless belt define an inner side and an outer side;
• a crystallization surface (11) formed on the outer side of said upper run (17) of the endless band or belt (12);
• mounting means (19, 20, 24) for mounting said upper run of the band or belt at an angle of inclination (.alpha.) which places one end portion of said endless band or belt at a higher elevation, with respect to a horizontal plane and defining an upper end portion, that an opposite, or lower end portion of the upper run;
• at least one feeding station (21, 31, 35) for applying the liquid mixture onto the crystallization surface (11) at a level above said lower end portion;
• speed controllable drive means (D, 13) coupled to said endless band or belt for driving said endless band or belt in a direction such that the upper run of said band or belt runs upwardly;
• means (39, 42, 43, 45) for controlling the temperature, by selective cooling or heating, of said upper run (17) of the band or belt (21) and hence of said crystallization surface (11), said temperature control means being located in heat transfer relation with respect to said upper run,
• said temperature control means including a plurality of heat exchange means (43, 59) forming a plurality of temperature zones on said crystallization surface, and thereby forming a temperature profile on said crystallization surface along the length thereof, in which the temperature at said upper end portion will differ from the temperature of the lower end portion and vary between a higher and a lower temperature on said crystallization surface;
• a control unit (C) controlling the speed of operation of said drive means (D) and hence of said endless band or belt (12), and said temperature control means (39, 42, 43, 45) to thereby control the temperature profile on said crystallization surface (11);
• and
• wherein said mounting means comprise adjustable means (24) for adjusting said angle of inclination (.alpha.) and for setting said angle at a level as a function of the liquid mixture and the substance to be crystallized therefrom at said controlled speed of said drive means (D) and said temperature profile controlled by said temperature control means (39, 42, 43, 45).