Abstract: Apparatus for separating gaseous mixtures comprising a pair of separator vessels each packed with adsorbent material such as silica gel, activated alumina or molecular sieves or absorbent material such as lithium chloride with serving as separating material, wherein a separating cycle during which air containing water vapor or gaseous mixture consisting of two or more different components such as nitrogen and oxygen is fed into one of the separator vessels to remove one or more components from the mixture and a regenerating cycle during which the processed gaseous mixture is partially fed into the other separator vessel to remove the quantity of components previously adsorbed or adsorbed by the separating material present within this separator vessel and thereby to regenerate the separating material are alternately repeated and wherein there are provided regeneration promoting separator vessels for further removal of the components to a lower concentration.