Portable oxygen concentrator

[1] They were initially conceived of as a method of providing a continuous source of home oxygen without the use of heavy tanks and frequent deliveries.

[6] The basic set up of a POC is a miniaturized air compressor, a cylinder filled containing the sieve, a pressure equalizing reservoir and valves and tubes.

During the first half of the first cycle the internal compressor forces this air through a system of chemical filters known as a molecular sieve.

As the pressure in the first cylinder drops the nitrogen is desorbed, the valve is closed, and the gas is vented into the ambient air.

Most of the oxygen produced is delivered to the patient; part is fed back into the sieves (at greatly reduced pressure) to flush away left over nitrogen, and prepare the zeolite for the next cycle.

[14] Medical: Commercial: On 13 May 2009, the United States Department of Transportation (DOT) ruled that air carriers conducting passenger flights of greater capacity than 19 seats must allow travelers with a disability to use an FAA-approved POC.

[15] Nighttime use has been facilitated by the advent of alarms and technology that detects a patient's slower breathing during sleep and adjusts the flow or bolus size accordingly.