Inserts for membrane spacers

Claim 1

AN ELECTRODIALYSIS CELL COMPRISING TWO ELECTRODES, A SERIES OF ION-EXCHANGE MEMBRANES BETWEEN TWO ELECTRODES DIVIDING THE SPACE THEREBETWEEN INTO COMPARTMENTS, SPACERS AROUND THE EDGES OF THE MEMBRANES IN THE SHAPE OF OPEN FRAMES, SEPARATING THE MEMBRANES, SAID MEMBRANES AND SPACERS EACH HAVING SUCCESSIVELY COMMUNICATING HOLES THROUGH THEM COOPERATING TO FORM CONDUITS THROUGH THE CELL AT RIGHT ANGLES TO THE MEMBRANES, SOME OF SAID HOLES EXTENDING TO THE INSIDE EDGES OF SAID SPACERS TO FORM PASSAGES THROUGH THEM SUBSTANTIALLY RECTANGULAR IN PLAN CONNECTING SAID CONDUITS TO SAID COMPARTMENTS, AND A RECTANGULAR INSERT FILING EACH PASSAGE, SAID INSERT BEING SUBSTANTIALLY EQUAL IN THICKNESS TO THE SPACER AND SUPPORTING THE ADJACENT MEMBRANES ACROSS THE WIDTH OF THE PASSAGE WHILE PREVENTING THEM FROM BEING DEFORMED INTO THE PASSAGE, SAID INSERT COMPRISING AT LEAST TWO SHEETS, SAID SHEETS HAVING HOLES THEREIN SO POSITIONED AND DIMENTIONED THAT EACH HOLE IN EITHER SHEET IS CAPABLE OF OVERLAPPING AT LEAST TWO HOLES IN THE OTHER SHEET IN A CERTAIN RELATIVE POISTION OF THE SHEETS TO ONE ANOTHER, SAID SHEETS BEING POSITIONED IN PLANES PARALLEL TO THE PLANES OF THE MEMBRANES AND BEING FIXED FACE TO FACE IN SUCH RELATIVE POSITIIN TO ONE ANOTHER, WHEREBY TO FORM A TORTUOUS PASSAGE FROM ONE EDGE OF THE INSERT TO THE OTHER.