GB837866A - Improvements in and relating to electrolysers - Google Patents

Abstract

837,866. Pressure electrolysers. LONZA ELECTRIC & CHEMICAL WORKS Ltd. March 29, 1956 [April 1, 1955 (6); July 7, 1955; Jan. 14, 1956], No. 9900/56. Class 41. An electrolyser of filter press form, Figs. 1 and 4, suitable for operating at not less than 5 atmospheres gas pressure, has the electrolyte space Z of each cell divided into two electrode compartments A and K by diaphragms 48 peripherally bounded by two steel rings (41, 42) enclosing an electrically insulating packing ring 47 (e.g. of asbestos board) each cell being separated from adjacent cells by metallic partitions 45, 46 in the form of sheet metal discs each with a smooth rim R tightly sealed to the corresponding steel ring and having a central area whereon a plurality of studs (45a and 45b, 46a and 46b) are pressed out alternately on either side, the heads thereof making contact with perforated electrodes (50a, 49, 50, 49b) adjacent on either side of, and separated by, said diaphragms. The sheet metal discs 45 and 46 may be set in grooves 51 and 52 in the steel rings. Slots 53 in the steel rings tightly engage the insulating packing ring 47 and the edges of the diaphragms and perforated electrodes are gripped by the steel rings, the inner edge of the insulating packing rings 47 protruding between the diaphragm and the perforated electrodes. As shown in Fig. 6, the gas-collecting manifolds 24 and 25 (not shown) comprise sleeves 54 and 54a of halogen substituted polyethylene (preferably mixed with asbestos) passing through openings in the partitions 45 and 46 and attached thereto by screwed-on rings 55 and 55a, corresponding holes being punched in the diaphragm and the perforated electrodes. The manifold 24 is connected by cross passages 56 and 56a to the anode compartments A and the manifold 25 similarly to the cathode compartments. A manifold 36 of the same construction but connected to both compartments is provided for returning electrolyte to the cells. Active coatings of platinum black or palladium may be applied to the perforated electrodes and the packing insulating rings may comprise a pliable core material covered with a sheath of polyfluoroethylene as described in Specifications 837,864 and 837,865. As shown in Fig. 1, several hundred of the cells 1 having the form of circular discs are combined in a stack clamped between heavy end-plates 2 and 3 being clamped by six tie rods of which 4, 8, 9 are shown in Fig. 1; these tie rods have a groove along their inner axis in which are inserted porcelain bobbins bearing against the cells. The one pole of the current source U is connected to plates 2 and 3 and the other through conductor 11 to the central plate 12 of the assembly. The stack of cells is divided into sub-assemblies I, II, III, IV, each enclosed within auxiliary end plates, e.g. 13 and 14, and joined by tie-rods, e.g. 15 and 17. Gas separator drums 20 and 21 (not shown) are connected by elastic tube bends 22 and 22a and 23 and 23a (not shown) to manifolds 24 and 25 (not shown). Liquid electrolyte carried to the separator drums along with effluent gases is separated from the gases and led back through pipe 31, filter 34 and branch pipes 31a and 31b (which engage either end of the stack) and manifold 36. The circuit is controlled by flow meter 33 and pump 35 so that the entire electrolyte volume circulates once in not more than 2 hours. Also present in this circuit are non-return valves 32, 37 and 38 and 32a (not shown). The drums 20 and 21 intercommunicate by U-tubes 26 and are connected to float-controlled blow-off valves 29 and 30 (not shown) through scrubbers 27 and 28 (not shown). Specifications 680,186 and 681,895 also are referred to.