Abstract: A new method of measuring the flow capacity of cell gas in the chlorate cell process equipped with an oxygen cathode is applied to investigate the influence of changes in the concentrations of solutions (chloride, chlorate, hypochlorite and addition of foreign salts) and changes in the operation parameters (current density, temperature, pH and flowvelocity) as well as changes in the anode materials on chlorate current efficiency. The concentrations of salts (chloride and chlorate), current efficiency and energy consumption as a function of time are given in a batch process with sodium chloride from 310 g/L to 30 g/L.