GB1421576A - Continuously operable apparatus for crystallisation character ised in having a device for supplying the same - Google Patents

Abstract

1421576 Evaporative crystallization SOC FIVES LILLE-CAIL 22 March 1973 [29 March 1972] 13935/73 Heading BIG Apparatus for crystallizing by evaporation and which includes regulating the supply of sub-saturated solution and also washing the inner walls of the apparatus with this solution comprises a vertically disposed closed cylindrical tank in whioh the lower portion of the tank is divided into a plurality of compartments by radial partitions and wherein successive compartments communicate with each other by apertures formed in the partitions except for the outlet compartment and that one situated immediately after it and a device for supplying sub-saturated solution comprising a pipe with a plurality of holes spaced along the pipe from which is projected the solution, means for rotating the pipe about a vertical axis above partitions and means for varying in accordance with the position of the pipe, the volume of solution which the pipe discharges into each compartment. The solution dischaged may be varied by altering the rotational speed of the pipe or the supply rate of the solution to the pipe in accordance with a predetermined cycle. The rotational speed of the pipe when driven by a motor may be controlled by a rotary switch on an arm rotating synchronously with the pipe and actuating fixed contact makers as the pipe passes from compartment to compartment. The pipe may also be driven by a two speed motor adjustable for each compartment. The rotational speed of the pipe may also be varied by a suitably profiled cam fixed on the shaft of the pipe. The volume of solution supplied to the pipe may be varied by a valve arranged in the supply conduit for the pipe. Figures 1 and 2 show respectively a vertical section of a crystallization apparatus and device, and a cross-section of the apparatus, wherein tank 10 is divided into eight compartments by partitions 15 which contain aperatures 28 except in compartments 0 and 7. In compartment 0 the solution is concentrated by heater 30, until saturated, whilst from 7 the desired crystalline material is recovered from conduit 24. The jet pipe 32 is rotated by a geared motor (not shown) and distributes the unsaturated solution successively and periodically into all the compartments.