A portable oxygen concentrator, comprising: at least one removable module comprising a housing; at least one adsorbent bed contained in said housing; wherein said adsorbent bed comprises at least one molecular sieve material; wherein said molecular sieve material has a substantially spherical shape; wherein the ratio of the length of said absorbent bed to the diameter of said absorbent bed is less than about 4.8:1; and wherein said absorbent bed is capable of a ratio of product flow rate to mass of said molecular sieve material of greater than 3.3 ml/min/g; a compressor; a manifold to control gas flow into and out of said removable module; at least one removable battery cell; wherein said portable oxygen concentrator weighs less than about 5 kg; and wherein said portable oxygen concentrator is capable of producing up to 3 liters of oxygen per minute at 22° C. and 1 atmosphere pressure. view more

A portable oxygen concentrator of claim 22, wherein said at least one removable module comprises one adsorbent bed.

A portable oxygen concentrator of claim 22, wherein said molecular sieve material comprises zeolite.

A removable module of claim 22, wherein said removable module is replaceable by a user.

A portable oxygen concentrator system, comprising: at least one removable module comprising a housing; at least one adsorbent bed contained in said housing; wherein said adsorbent bed comprises at least one molecular sieve material; wherein said molecular sieve material has a substantially spherical shape; wherein the ratio of the length of said adsorbent bed to the diameter of said adsorbent bed is less than about 4.8:1; and wherein said adsorbent is capable of a ratio of product flow rate to mass of said molecular sieve material of greater than 3.3 ml/min/g; a compressor; a manifold to control gas flow into and out of said removable module; and at least one removable battery pack; wherein said portable oxygen concentrator system weighs less than about 5 kg. view more

A portable oxygen concentrator system of claim 12, wherein said at least one removable module comprises one adsorbent bed.

A portable oxygen concentrator system of claim 12, wherein said molecular sieve material comprises zeolite.

A portable oxygen concentrator system of claim 12, wherein said removable module is replaceable by a user.