GB913403A - Apparatus for treating liquids electrolytically - Google Patents

Abstract

913,403. Electro-dialytic cells. AMERICAN MACHINE & FOUNDRY CO. July 17, 1961 [July 20, 1960], No.25802/61. Class 41. An electro-dialytic cell consisting of a stack of anionic and cationic permeable membranes forming diluting and concentrating cells, is precharged in the cathode compartment with a water-soluble acid compound, e.g. solid sodium bisulphate; oxalic, citric or phosphoric acid, to supply acid and thus reduce the precipitation of solids on the membranes. Each electrode com. partment may be provided with the solid acid, so that current may be reversed. An anionic membrane is mounted as the last member of the stack adjacent the electrode compartment containing acid. A suitable apparatus comprises a stack of anionic membrane 48A, gasket, cationic membrane 48K &c. ending in an anionic membrane 48A, clamped together between thick gaskets 66, insulating sheets 65, carrying electrodes 67, 72, and outer plastic blocks 33, 34, held by steel plates 30. The end anionic membranes are covered by a sheet 69 of porous non-woven material resistant to chlorine, e.g. for brine electrolysis. The cathode chamber 67 contains a solid salt 25, which may also be in the form of loosely packed powder. The upper part of each electrode chamber is vented through pipes 35, 37 leading to closures 22 having perforated lids 23, through which gases may escape. Water may be added through these closures. Any base produced in the catholyte is neutralized by the acid present, and acid water may move through the anionic membrane 48A. If both electrode compartments are charged with acid, the current is periodically reversed. The water or liquid to be treated enters through two pipes 39 (one shown) and leaves the stack through two pipes 41 (one shown). A gasket (Fig. 3, not shown) having a cut-out area communicating with one manifold supply pipe is described.