| 摘要 |
531,418. Photoelectric control of water softening plant. PERMUTIT CO., Ltd., HOLMES, E. L., and PRESCOTT, W. G. July 3, 1939, No. 19353. [Class 40 (iii)] [Also in Group I] Plant in which water is passed successively through hydrogen-cation-exchange material and anion-exchange material is provided with means for adding silver nitrate to the effluent or a part thereof. Turbidity following such addition indicates the need for regeneration and may control the operation of the plant automatically. In an example described silver nitrate is added continuously to the effluent water or a stream separated therefrom and the mixture passed through a glass tube provided with a source of light and a light-sensitive cell in a circuit provided with a galvanometer, which serves to indicate when regeneration of the exchange material is necessary. The circuit may also include relays for controlling the operation of the plant automatically. The silver nitrate may be added in an acid solution so as to maintain the pH value of the mixture below 4. |
