Patent ID: 8679695

Claim:
A system for supplying a liquid electrolyte to cell stacks arranged at a plurality of different heights, with a plurality of cell stacks at each different height, each cell stack comprising a stack of cells with electrodes extending in vertical planes; the system comprising a plurality of supply tanks for containing liquid electrolyte, one for each of the different heights, each supply tank having an opening to ensure that the surface of the liquid electrolyte is at atmospheric pressure and connected by feed ducts to feed electrolyte to the plurality of cell stacks at that height; an electrolyte storage tank, and means to supply electrolyte from the electrolyte storage tank to the highest supply tank; wherein each supply tank incorporates an overflow weir and an outlet duct communicating with the weir, for each supply tank except the lowest supply tank the outlet duct being arranged to supply overflowing electrolyte to a supply tank at a lower height, wherein the electrolyte storage tank is below the lowest supply tank, and the outlet duct from the lowest supply tank feeds into the electrolyte storage tank; and wherein the cell stacks are cell stacks, through which electrolyte flows continuously, in operation, between an inlet and an outlet of each cell stack, and out-flowing electrolyte from the outlet of each cell stack is returned through a cell stack outflow duct to the electrolyte storage tank.