Weight-optimized portable oxygen concentrator

1. A system for producing an oxygen-rich gas comprising

(a) a primary gas mover including a first compressor adapted to compress atmospheric air to provide pressurized feed air and a second compressor adapted to compress a waste gas from subatmospheric pressure to atmospheric pressure, wherein the primary gas mover is characterized by a weight W p ;

(b) a drive motor adapted to drive the first and second compressors;

(c) a rechargeable power supply adapted to supply power to the drive motor, wherein the rechargeable power supply is characterized by a weight W b ; and

(d) a pressure/vacuum swing adsorption unit adapted to separate the pressurized feed air into an oxygen-rich product at a product flow rate F p and an oxygen-depleted waste gas, wherein the adsorption unit comprises a plurality of adsorber beds containing an adsorbent, wherein the total amount of the adsorbent contained in the adsorber beds is characterized by a total adsorbent weight W a ;

wherein the combined weight, W t , of the adsorbent, the primary gas mover, and the rechargeable power supply is characterized by the expression

0.75 F p <W t <2.02 F p

where F p is in liters per min (at 23° C. and 1 atma pressure) and W a , W p , and W b are in pounds.

2. The system of claim 1 wherein the battery is characterized by an operating run time in hours, t r , between maximum and minimum working charge, and wherein the system is further characterized by any of the expressions

0.21 F p <W a <0.61 F p ,

0.36 F p <W p <0.70 F p ,

0.18 F p <W b <0.71 F p , and

0.10 F p t r <W b <0.40 F p t r .

3. The system of claim 1 wherein the plurality of adsorber beds comprises four or more beds.

4. The system of claim 3 wherein the plurality of adsorber beds consists of four beds.

5. The system of claim 1 wherein each of the first and second compressors are selected from the group consisting of scroll, diaphragm, piston, and rotary vane compressors.

6. The system of claim 5 wherein the first and second compressors are scroll-type compressors.

7. The system of claim 1 having a total weight of less than 12 pounds.

8. The system of claim 7 having a total-weight of less than 10 pounds.

9. The system of claim 8 having a total weight of less than 8 pounds.

10. The system of claim 1 wherein the adsorbent is selected from the group consisting of zeolite X exchanged with one or more metallic cations selected from the group consisting of lithium, calcium, zinc, copper, sodium, potassium, and silver.

11. The system of claim 10 wherein the adsorber beds further comprise an additional adsorbent selective for the adsorption of water and carbon dioxide from air and wherein the additional adsorbent is selected from the group consisting of (1) activated alumina and (2) zeolite X exchanged with one or more metallic cations selected from the group consisting of lithium, sodium, and potassium.

12. The system of claim 1 which further comprises a conserver.

13. The system of claim 1 wherein the rechargeable power supply is a battery.

14. The system of claim 1 wherein the rechargeable power supply is a fuel cell.

15. The system of claim 1 which further comprises an external case surrounding the primary-gas mover, drive motor, rechargeable power supply, and pressure/vacuum swing adsorption system, and a user display/control panel mounted on the outer side of the case.

16. The system of claim 15 having a total weight of less than 12 pounds.

17. The system of claim 16 having a total weight of less than 10 pounds.

18. The system of claim 17 having a total weight of less than 8 pounds.

19. A system for producing an oxygen-rich gas comprising

(a) a primary gas mover including a first compressor adapted to compress atmospheric air to provide pressurized feed air and a second compressor adapted to compress a waste gas from subatmospheric pressure to atmospheric pressure, wherein the primary gas mover is characterized by a weight W p ;

(b) a drive motor adapted to drive the first and second compressors;

(c) a rechargeable power supply adapted to supply power to the drive motor, wherein the rechargeable power supply is characterized by a weight, W b , and an operating run time, t r , between maximum and minimum working charge; and

(d) a pressure/vacuum swing adsorption unit adapted to separate the pressurized feed air into an oxygen-rich product at a product flow rate F p and an oxygen-depleted waste gas, wherein the adsorption unit comprises a plurality of adsorber beds containing adsorbent, wherein the total amount of the adsorbent contained in the adsorber beds is characterized by a total adsorbent weight W a ;

wherein the system is characterized by any of the expressions

0.21 F p <W a <0.61 F p ,

0.36 F p <W p <0.70 F p ,

0.18 F p <W b <0.71 F p , and

0.10 F p t r <W b <0.40 F p t r ,

where F p is in liters per min (at 23° C. and 1 atma pressure), t r is in hours, and W a , W p and W b , are in pounds.

20. The system of claim 19 which further comprises additional elements including electrical wiring and control systems, a case or housing, and a user display/control panel mounted on the outer side of the housing, wherein the oxygen generation system and the additional elements are combined to form a portable oxygen concentrator, and means for the user to carry the portable concentrator unit.