GB555335A - Improvements relating to the softening of water - Google Patents

Abstract

555,335. Purifying water. PERMUTIT CO., Ltd., AKEROYD, E. I., and HOLMES, E. L. Feb. 4, 1942, No, 1482. [Class 46] In the removal of salts from water, particularly in lime or lime-soda softening by crystallisation on to nuclei maintained in suspension within a reaction vessel through which the water with an added reagent is caused to flow upwardly, the water is so introduced that it flows uninterruptedly upwards through a vertical parallelsided reaction vessel 1 at a substantially uniform rate throughout the suspended bed and the speed of flow is correlated with the total quantity, size and concentration of the nuclei to ensure that the desired reactions are complete and all, or substantially all, the crystallisation has taken place when the water leaves the tap of the bed. The shape of the bottom of the vessel and the water inlet are correlated so that, at starting, the bed of nuclei is carried into suspension by the incoming water. The water may be introduced by a central pipe 3 and the reagent by a branch pipe 4 into a conical or pyramidal bottom 2 of comparatively small base angle. With a somewhat wider base angle, the reagent may enter by a pipe 7 and water by a pipe 5 having a conical outlet 6. With a still wider base angle, or a rounded bottom, the water may be supplied through a distributor 8. The reagent may be supplied through a branch pipe 11 adjacent the outlet of the water pipe 10. In lime softening with nuclei of 16 - - 32 mesh size and .6 mm. average diameter, the concentration of the bed should be above 30 per cent and may be as high as 80 per cent and the speed of flow between 2 and 4 feet per minute. As the nuclei grow, the speed may be increased to maintain the bed in suspension or it may be maintained constant and deposited nuclei removed. The treatment may be carried on at elevated temperature and pressure. Specifications 507,750 and 522,430 are referred to.