GB777102A - Improvements relating to ion-exchange treatment of water - Google Patents

Abstract

777,102. Softening water. UNITED FILTERS & ENGINEERING, Ltd. June 10, 1954 [April 1, 1953], No. 9027/53. Class 46. [Also in Group XXXVI] The conductivity of effluent from a cation exchanger is measured at two points effectively time-spaced along the effluent path, and during a working run these conductivities are equal ; when they differ by an optimum amount the exchanger is manually or automatically regenerated, and when, near the end of a rinse following the regeneration, they are equal again, the rinsing is terminated and normal working resumed. Effluent from a hydrogen exchanger X is divided at Y, part flowing direct to a conductivity cell E1 and the remainder flowing through a time-lag device T in the form of a baffle tank (as shown), a coil of piping or the like to a second conductivity cell E2 so as to ensure a predetermined time-lag between the effluents in the two cells. When regeneration has become necessary the electrical conductivity of the effluent passing through conductivity cell E1 will be lower than that of the effluent passing through cell E2 (which represents the effluent at an earlier period). This results in a differential conductivity which is at once indicated by a conductivity meter M, and this differential conductivity can be arranged to give a signal, or automatically initiate regeneration, when it reaches an optimum value. During regeneration the conductivity meter M is automatically put out of service and valves A and B closed. After a predetermined period, when the rinse operation is nearly complete, valve B is opened and the meter M comes into service so as to show the differential conductivity between the rinse water passing continuously through the cell El and the lower conductivity effluent still retained in the time-lag device T and cell E2. When the rinse-water conductivity falls to approximately that of the water in the time-lag device T and cell E2 the hydrogen exchanger is manually or automatically put back into service and valve A is opened. If the apparatus is to be operated intermittently and therefore shut down before exhaustion of the exchanger, it would be necessary to close a valve (not shown) in the downpipe feeding cell E2 when valves A and B are closed, and to open it again when valves A and B are opened. The cation exchanger may be used in conjunction with an anion exchanger.