Continuous pressure change adsorption process to purify gases and separate gas mixts. esp. to enrich oxygen from air. Uses at least three adsorbers (A1,A2,A3) each running through a work cycle consisting of adsorption, desorption and pressure build up stages. The adsorber work cycles are set against each other such that at the same time, two adsorbers are in the same cycle stage. The overlap of these same cycle stages occurs in the end phase of the cycle stage of the adsorber which begins this stage first.
