Improvements in or relating to the softening of water

摘要

576,014. Softening water. FILTRATORS, Ltd., and STREATFIELD, E. L. Aug. 16, 1944, No. 15632. [Class 46] A process of softening water includes passing the water mixed with lime or lime and soda through a vessel containing crystallisatibn nuclei such as grains of sand or .marble and then passing it through a bed of stabilising material serving to remove free lime and calcium carbonate. The stabilising material may be carbonaceous zeolite in the spent condition. In the construction shown a container A is fitted with a chamber B which contains crystallisation nuclei of marble granules B2and is provided with inlet pipes G, H for the supply respectively of water to be softened and lime or lime and soda. A perforated plate C supports a bed D of graded gravel, anthracite or like material above which is a bed of carbonaceous zeolite E. The upper part of the zeolite is maintained in a substantially spent condition while the lower part is comparatively fresh. A pipe L leading to the bottom of the container A is provided with three valved branches L', L2, L3,for the supply respectively of water, dilute acid and brine. The water to be softened mixed with lime or lime and soda passes up through the chamber B and overflows on to the zeolite, the softened water escaping through pipe K. To regenerate the zeolite water is admitted to the container A through pipe L1 to flood the bed E and carry away through a pipe M any lime accumulated on the bed. Dilute acid is next admitted, followed by brine, and finally by more flushing water. Specification 576,019 is referred to.