NOVELTY - The system has a reactor stack (2) which comprises multiple spaced apart electrode plates adapted to receive electrolyte solution placed between the plates. Each plate has an upper outlet aperture and a lower inlet aperture. A pump (18) is provided to pump electrolyte solution in a circuit from the electrolyte solution inlet, through the reactor stack, and back to a separator/reservoir, and in which upper and lower apertures are sufficiently large to allow pumped flow of electrolyte solution through reactor stack, and upper apertures are larger than lower apertures.    USE - Hydrogen gas generator system used in welding, brazing or cutting, flame polishing device and vehicle (all claimed) e.g. aircraft, rocket, missile, or spacecraft.    ADVANTAGE - The flow is enhanced by use of the pump. The stack comprises cell separators which bears an internal form specified in such a way as to enhance flow across the cell in an even flow pattern. Thus the mass transport across the cell is improved and even cooling of the active area of cell is ensured. The spacing of the narrow dimension facilitates high velocity flow across the plates which helps remove gas bubbles from the plates and increases the efficiency of the electrolysis operation. Thus the reduction in the concentration of the electrolyte improves efficiency by limiting current leakage.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following    (i) A hydrogen gas generating system comprising a reactor stack having at least two electrode plates adapted to perform electrolysis on an electrolyte solution disposed between the electrode 15 plates and generate oxygen and hydrogen gases, the reactor stack comprising a base having an inlet for electrolyte solution and a top having an outlet for a mixture of electrolyte solution and hydrogen/oxygen gas, wherein each electrode plate comprises an upper aperture and a lower aperture that are sufficiently large to allow pumped flow of electrolyte solution through the plates, and wherein the upper aperture is larger than the lower aperture.    (ii) A reactor stack suitable for use in a hydrogen gas generator system and adapted to perform electrolysis on an electrolyte solution, the reactor stack comprising a plurality of spaced apart electrode plates having an upper outlet aperture and a lower inlet aperture that are sufficiently large to allow pumped flow through the reactor stack, the plates being separated by sealing spacers which define the distance between the plates and a path for movement of electrolyte solution between adjacent plates from the lower inlet aperture to the upper outlet aperture, and wherein the upper apertures are larger than the lower apertures.    DESCRIPTION OF DRAWING(S) - The drawing shows a front view of the hydrogen gas generator system.    Reactor stack (2)    Separator tank (3)    Electrolyte gas outlet (4)    Electrolyte solution inlet (5)    Pump (18)