An oxygen concentrator is a device that concentrates the oxygen from a gas supply (typically ambient air) by selectively removing nitrogen to supply an oxygen-enriched product gas stream.

An oxygen concentrator has an air compressor, two cylinders filled with zeolite pellets, a pressure equalizing reservoir, and some valves and tubes. In the first half-cycle the first cylinder receives air from the compressor, which lasts about 3 seconds.

At the end of the first half of the cycle, there is another valve position change so that the air from the compressor is directed to the second cylinder.

The pressure in the first cylinder drops as the enriched oxygen moves into the reservoir, allowing the nitrogen to be desorbed back into gas. Partway through the second half of the cycle, there is another valve position change to vent the gas in the first cylinder back into the ambient atmosphere, keeping the concentration of oxygen in the pressure equalizing reservoir from falling below about 90%. The pressure in the hose delivering oxygen from the equalizing reservoir is kept steady by a pressure reducing valve.

Oxygen concentrators are considered sufficiently foolproof to be supplied to individual patients as a prescription item for use in their homes. Typically they are used as an adjunct to CPAP treatment of severe.There also are other medical uses for oxygen concentrators, including COPD and other respiratory diseases.

Portable Oxygen Concentrator

These machines weigh around 2-3 kg and are basically used while travelling or during a flight. They can provide continuous flow only upto 2 lpm. For higher intermittent flows there is burst mode which only delivers Oxygen when patient is inhaling and it can provide upto 6 lpm. eg. Philips Respironics SimplyGo , Philips Respironics SimplyGoMini

Pros-

1.    Light weight , can easily be used while travelling.

2.    Have rechargeable batteries that provide a decent backup even without a nearby power source.

Cons –

1.    Can provide continuous flow only upto 2 lpm.

2.    Burst mode gives oxygen