Patent ID: 7491261

Claim:
A method of increasing the oxygen concentration of a gas, comprising: a) providing first and second chambers in fluid communication with one another, wherein said first chamber has a first feed end containing first molecular sieve material for adsorbing nitrogen and a first product end separated from said first feed end by a gas permeable first boundary member which restricts said first molecular sieve material to said first feed end, and wherein said second chamber has a second feed end containing second molecular sieve material for adsorbing nitrogen and a second product end separated from said second feed end by a gas permeable second boundary member which restricts said second molecular sieve material to said second feed end, wherein a first conduit selectively supplies compressed air to said first or second feed ends, wherein a second conduit selectively supplies gas from said first or second product ends to an end use, and wherein a third conduit selectively supplies gas between and to said first and second boundary members; and providing a means for controlling as flow, and, by operation of said means for controlling gas flow, said method, in one cycle of a plurality of cycles, comprising the steps of: b) compressing air-by-air compression means into said first chamber from said first feed end through said first conduit; c) delivering oxygen enriched gas from said first product end through said second conduit for said end use; d) releasing oxygen-enriched gas from the first chamber to said second chamber through said third gas conduit; e) venting said first chamber as exhaust from said first feed end; f) compressing air into said second chamber from said second feed end; g) delivering oxygen enriched gas from said second product end through said second conduit for end use; h) releasing oxygen enriched gas from said second chamber to said first chamber through said third gas conduit; and, i) venting said second chamber as exhaust from said second feed end.