GB852272A - A multi-cell-stack for the electro-dialysis of electrolyte solutions - Google Patents

Abstract

852,272. Electrodialysis. ISRAEL, PRIME MINISTER OF, and MENTS, M.V. April 10, 1959 [April 29, 1958], No. 12152/59. Class 41 A multi-cell electrodialytic apparatus comprises gasket layers each enclosing a cell space 12 and alternate anion-and cation-selective membranes 1 each disposed between two gasket layers and forming the cell space walls, the spaces 12 being oblong and alternate gasket layers being turned through 90 degrees so that the central parts of the spaces 12 register throughout the apparatus, but the end parts of the spaces 12 register between alternate gasket layers only and form part of two ducts serving to introduce liquid into and remove it from all the spaces 12 which are similarly oriented. Each gasket layer is formed by two members 10, 11 having recesses 13 which co-operate with the end parts of each adjacent space 12 to form the ducts, the membranes 1 overlying the central parts only. The central parts of the spaces 12 may have permeable spacers 4 which may be integral with the gaskets 10, 11, and peripheral washers may separate adjacent gaskets. The stack of gaskets and membranes is enclosed in a shell and secured, e.g. by bolts, between end plates to which electrodes are bolted, suitable liquid connections being made. In a modification, the gaskets are frames having large central oblong apertures corresponding to the spaces 12, and two smaller parallel oblong holes, one at each side of the central aperture, corresponding to the recesses 13. If the gaskets are rigid, they may have recesses for the membranes. Otherwise washers are employed as before. In another modification, Fig. 7, each gasket comprises two strips 24, the membranes 27 and spacers 26 (if employed) extending over the whole space between each two strips. The stack is mounted between end plates, four posts, each of which may consist of superposed separate elements, engaging corner recesses 25. Hoods form headers at each of the four sides of the stack, and partitions in the hoods may lead liquid separately to each cell space formed between adjacent membranes 27. In this embodiment, liquid is led straight through a cell space from the header, and no longitudinal ducts exist.