problems as compared to those existing with a plurality of parallel connected anodes and cathodes except for the gas space dams 22 and 23 the feed compartment 18 and the product compartment 20 are open to the bipolar electrode compartment bipolar electrodes 21 which may be made of graphite are fitted with a plurality of electrolyte flow through passages 16 so that electrolyte may flow through the cell in a substantially non turbulent manner from the feed end to the discharge end electrodes 21 are mounted on piers 26 made of refractory as shown in fig3 a gap 27 is left in each pier 26 to permit insertion of a lifting hook when worn electrodes are to be removed the bottoms of main anode 15 main cathode 19 and bipolar electrodes 21 all lie in substantially the same horizontal plane thus the main electronic path and main flow path for electrolyte through the cell is constituted by flow passages 16 through the electrodes the main anode advantageously is made of graphite and is water cooled the cell is covered with water cooled lids 28 which are fitted to the top surfaces of the cell sides and to each other with labyrinth seals each bipole compartment 29 and each bipolar electrode is fitted with a lid in addition the feed or inlet compartment 18 and the product or outlet compartment 20 are fitted with lids 30 and 31 respectively lids 30 and 31 interlock with adjacent bipole lids 28 to form a seal the feed compartment lid.