GB569660A - Fluid purification system - Google Patents

Abstract

569,660. Purifying liquids. AMERICAN CYANAMID CO., DURANT, W. W., and BLANN, W. A. Jan. 22, 1943, No. 1162. [Class 46] A liquid purification system comprising at least one bed C<1> of hydrogen activated cation active material and one A<1> of anion active material is provided with a further bed C<2> of hydrogen activated cation active material and a bed A<2> of buffered' anion active material which has been treated with a reagent to adjust the effluent fluid to a predetermined pH value, together with an element which is contacted by at least a portion of the effluent from the buffered bed and responds to the presence in it of ionic materials so as to provide an indication of the condition of the effluent, or to control its flow, or both The buffered bed maintains the pH value of the effluent substantially constant during normal operation of system, but when one or more of the preceding beds' becomes exhausted the pH value of the effluent undegoes a marked change which causes the responsive element to operate the indicator or shut off the flow of fluid through the system. The fluid flowing into the bed C<2> should have a low content of ionizable anions and cations, for example, less than 20 parts in a million. The responsive element in the test cell may comprise a glass and a reference electrode actuating a pH meter, or a pair of electrodes connected to means for measuring the resistance between them. Alternatively, an indicator may be added to the effluent which, when it changes colour, causes a photoelectric cell, on which a light beam passing through the effluent falls, to operate an indicator or control mechanisms. The control mechanism may comprise a valve operated through relays and a solenoid to shut off the flow of fluid, together, if desired, with other valves which supply regenerating solution and washing fluid to one or more of the beds of ion active material.