Patent ID: 8753435

Claim:
An ambulatory oxygen concentrator comprising: a pressure swing adsorption system adapted to generate a flow of oxygen enriched gas, wherein the pressure swing adsorption system includes: a compressor that comprises a motor, and two or more sieve beds that are charged and purged to extract oxygen-enriched gas from ambient air using sieve bed pressurization and sieve bed purging; battery adapted to provide power to the pressure swing adsorption system, wherein the oxygen concentrator has a total weight of less than about 10 lbs, the pressure swing adsorption system has a maximum continuous flow of 100% O 2 equivalent gas of between about 0.9 lpm and 1.2 lpm, the oxygen concentrator has a total volume less than about 800 in 3 , and the oxygen concentrator has a battery life of greater than 8 hours, wherein the battery has a maximum current that can be drawn, wherein the oxygen concentrator is configured to limit current drawn from the battery by the motor of the compressor during sieve bed pressurization to a first current, wherein the first current is no more than half of the maximum current.