Abstract: A pressure swing adsorption process and system including at least two adsorption beds and a segregated storage adsorption bed which is isolated from direct communication with the feed gas stream. During the process the pressures in the adsorption beds are equalized from the feed ends thereof at the end of adsorption in one of the beds and after pressurization of the other bed. The segregated storage adsorption bed is pressure equalized with a depressurizing adsorption bed and then after purging of the bed the segregated storage adsorption bed is equalized with that adsorption bed during repressurizing thereof. A pair of flow control valves are connected in a gas flow path connected to the outlets of the adsorption beds, each valve being located adjacent a corresponding one of the beds and allowing unrestricted flow away from the corresponding bed and controlled flow toward that bed.