Abstract: The apparatus comprises four cylindrical absorbent beds of small particle size (16.times.40 mesh) molecular sieve, two with zeolite and two with carbon molecular sieve. The units are integrated with each carbon bed in series with one of the zeolite beds, with valving at the inlets to the zeolite beds and at the outlets from the carbon beds. The oxygen purity of the gas is increased by selectively adsorbing and exhausting the nitrogen component in the zeolite beds and the argon component in the carbon beds. In a two step cycle, during step 1 of the cycle one pair of beds (one zeolite and one carbon) receives high pressure air as feed gas which pressurizes the beds and establishes a product oxygen flow. Simultaneously, the high pressure gas in the other pair of beds is vented to a lower pressure usually the ambient surroundings, and this depressurization serves to desorb the nitrogen and argon previously adsorbed during the high pressure phase of the cycle.

Abstract: The secondary purifier, composed of two cylindrical adsorbent beds and valving, is used to increase the oxygen concentration of the product gas comprising oxygen and argon from a zeolite molecular sieve concentrator. The oxygen purity of the gas is increased by selectively adsorbing and exhausting the argon component by the use of beds of small particle size (16.times.40 mesh) carbon molecular sieve. In a two step cycle, during step 1 of the cycle one bed receives high pressure 30 PSIA feed gas which pressurizes the bed and establishes a product oxygen flow, and the argon component of the air is removed by preferential adsorption in the carbon molecular sieve. Simultaneously, the high pressure gas in the other bed is vented to a lower pressure usually the ambient surroundings, and this depressurization serves to desorb the argon previously adsorbed during the high pressure phase of the cycle. In step 2 of the cycle the adsorbent beds exchange roles.