Abstract: An assembly of electrolyte compartment frames and a separating web for a filter press type of bipolar electrolytic apparatus includes gasketing material between the frames and the web near the ends of the web and a recess in such frames at an end of the web so that when the web differentially expands with respect to the electrolyte compartment frames it may move past the gasketing material and into the recess, thereby preventing distortion of the web and the frames and maintaining a liquid-tight seal between them.

Abstract: A separating web for use in an electrolytic apparatus having a plurality of cells containing anolyte and catholyte includes a pair of thin metal walls not in contact with each other, one of which is of a material, such as titanium, which is resistant to corrosion by and impermeable to such anolyte (which may be brine in an electrolytic cell used for the manufacture of chlorine and caustic or chlorate) and the other of which is of a material resistant to corrosion by and impermeable to such catholyte, which may be steel (which, although resistant to corrosion by the caustic catholyte of a cell for the manufacture of chlorine and caustic or chlorate, may allow the transmission of nascent hydrogen). The walls are separated from each other by a gas space, which may be vented for the escape of any molecular hydrogen formed therein from nascent hydrogen and the web is sealable in the electrolytic apparatus between adjacent cells thereof so as to separate such cells.