Working of an Oxygen Concentrator: These medical devices assist people who have a low level of oxygen in their blood. You just have to plug the device into an electrical outlet or by using a battery. If a battery is used, then it will need to be charged by plugging it into an electrical outlet. Oxygen Concentrator intakes air, purifies it, and then distributes the newly formed air. Before it goes into the concentrator, air is made up of 80 percent nitrogen and 20 percent oxygen. An oxygen concentrator uses that air then it comes out as 90 to 95 percent pure oxygen and 5 to 10 percent nitrogen. The nitrogen is separated to give the patient the highest quantity of oxygen possible, as it is difficult to get that percentage of oxygen without the help of a medical device.