GB739825A - Method and apparatus for dehydration of solutions by freezing - Google Patents

Abstract

739,825. Concentrating solutions by freezing. COMMONWEALTH ENGINEERING CO. OF OHIO. Jan. 25, 1954, No. 2182/54. Class 29. In apparatus for concentrating solutions by freezing comprising tanks 1 ... 5 each having a refrigerant jacket 6, scrapers 17, a circulating propeller 15 and a counterweighted bottom 11, the contents of each tank when sufficiently frozen are discharged by way of a trough 19 and shoot 21 into a screening device 22 from which the concentrated solution and small ice crystals pass by pipe 26 to pump 27a. The larger ice crystals pass by pipe 27 to a centrifuge 29 which discharges any concentrated solution through pipe 34 to the pump and the ice crystals through outlet 32. Tanks 1 ... 5 operate at successively lower temperatures and raw solution is first fed to tank 1 through pipe 9. This tank is discharged and the contents separated and supplied by pump 27a through header 35 and valved pipe 39 to the tank 2 and so on. When concentration is complete, the concentrated solution is withdrawn through pipe 41. As shown in Fig. 1, screen 22 is an apertured cylinder within which the material is mixed by a rotated helical member 24. As shown in Fig. 6, the tank contents are discharged on to an endless chain conveyer 43 through which concentrated solution and small ice crystals pass to a collector 44 from which they flow to the pump. The large ice crystals pass to a vibrated screen 45 and then to the centrifuge. Screen 45 may be omitted and conveyer 43 may be agitated. The tanks 1 ... 5 may be of progressively decreasing size.