An oxygen concentrator is a device used to provide oxygen to a patient at substantially higher concentrations than those of ambient air, in the absence of the preferred 100% oxygen in cylinders.

The oxygen concentrator is based around two cylinders, filled with a zeolite material, that selectively adsorb the nitrogen in the air. Each cylinder is brought up to 20 lbf/in² (138 kPa) in turn, while the other cylinder is brought down to 0 lbf/in² (0 Pa), allowing the captured nitrogen to dissipate. The cycle takes about 20 seconds, and allows for a continuous supply of oxygen at a flow rate of approximately five liters per minute at concentrations anywhere from 50 to 95 %.

They have the advantage of not being as dangerous as regular oxygen cylinders , which can greatly increase the combustion in a fire. This is particularly advantageous in military or disaster situations, where cylinders may be dangerous or infeasible. These devices are currently in use by the US military in the conflicts in Iraq and Afghanistan, as part of the equipment complement of the forward surgical teams. They are also available to individual patients needing supplementary oxygen, and are sold to oxygen bars and spas for their treatments.

Common models retail at around 2000USD, and require the authorization of a doctor for purchase.

Sources

• The New England Journal of Medicine -- Casualties of War -- Military Care for the Wounded from Iraq and Afghanistan
• The Oxygen Concentrator