An oxygen concentrator is an electrical unit which is used to supply oxygen for oxygen therapy at substantially higher concentrations than those of normal air to a patient.

Oxygen concentrators are used as an alternative to tanks of compressed oxygen or liquid oxygen. They are able to supply a continuous delivery of oxygen and the simplest ones are based around two cylinders. These cylinders are filled with a zeolite material which absorbs the nitrogen in the air.

In recent years a number of manufacturers have produced portable oxygen concentrators. These generally produce a smaller amount of oxygen and can also use demand flow, or pulse flow, which means that oxygen is only delivered when the patient is inhaling.

As the name suggests, patients can move around with these units as they are small and just need a standard electrical socket to plug into.