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How Does an Oxygen Concentrator Work?

If your doctor has suggested that you or a loved one use an oxygen concentrator for your oxygen therapy treatments, you may be wondering, “What is an oxygen concentrator and how does an oxygen concentrator work?” The basic idea is simple: Oxygen concentrators are able to purify and concentrate the surrounding air to produce oxygen as long as the unit has power.[1] Learn more below about the details of how oxygen concentrators pull the oxygen from the air around us, and why using this kind of oxygen generator improves oxygen therapy for you. 

What Is an Oxygen Concentrator?

An oxygen concentrator (sometimes called an O2 concentrator, oxygen machine or O2 concentrator, oxygen machine or oxygen generator) is a medical device used to deliver oxygen to those who require it. People may require an O2 concentrator if they have a condition that causes or results in low levels of oxygen in their blood. An oxygen concentrator must be obtained via prescription, and therefore cannot be purchased over the counter. If you need an oxygen machine but are unable to purchase one, an oxygen concentrator can be rented with your prescription as well.

How Does an Oxygen Concentrator Work?

So how does an oxygen generator work? Oxygen concentrators are electric or battery-powered devices that pull air from the room. It then separates and compresses oxygen from the air, while also removing nitrogen. You breathe in the purified air.2   An oxygen concentrator1

  1. Pulls in air from its surroundings
  2. Compresses the air, while the cooling mechanism keeps the concentrator from overheating
  3. Removes nitrogen and other impurities from the air via filter and sieve beds
  4. Adjusts delivery settings with an electronic interface
  5. Delivers the purified oxygen to the user via a nasal cannula or mask


Portable oxygen concentrators provide a safe source of oxygen-enriched air to provide medical oxygen as prescribed by a physician. Whether operating from battery power or plugged in, portable oxygen concentrators continue to produce oxygen as long as the unit has power. Oxygen concentrators do not need to be refilled. Additionally, many portable oxygen concentrators are lightweight and easy to carry.1

How does an oxygen concentrator work differently from other oxygen delivery systems? An oxygen concentrator has a compressing element, but it should not be confused with compressed oxygen or an oxygen tank. The compressed oxygen inside an oxygen tank is a set amount of oxygen that is dispensed to the user, eventually requiring a refill or replacement when the oxygen inside the tank runs out. People using compressed oxygen tanks must keep several tanks on hand to ensure that they do not run out of oxygen before receiving a refill. An oxygen concentrator, on the other hand, is an oxygen machine that pulls in air from the atmosphere, purifies it, compresses it and then delivers the oxygen-rich air continuously to the user. So, though it may sometimes be called an “oxygen generator,” an oxygen concentrator does not actually generate oxygen; instead, it pulls oxygen from the air around you.1

If you are wondering, “How does an oxygen generator work without requiring refills?” no refills are needed because the oxygen concentrator simply uses the surrounding air to create oxygen-rich air, meaning the oxygen supply will never run out as long as it is powered and has access to an air supply. Instead of refilling compressed air, an oxygen concentrator just needs access to power and the surrounding air.1


How Does a Portable Oxygen Concentrator Work?

How is a portable oxygen concentrator different from a stationary oxygen concentrator? Quite simply, portable oxygen concentrators are designed to travel with you, so they are lighter than stationary oxygen concentrators and are able to run for a certain amount of time on battery power before requiring that you plug in or recharge your oxygen machine. In some cases, stationary oxygen generator units are made to provide continuous flow oxygen, while most portable oxygen concentrator units provide pulse does oxygen. Otherwise, portable concentrators work the same way as a stationary system. The difference is in how you use them.1


Why Choose an Oxygen Concentrator Over an Oxygen Tank?

An oxygen concentrator offers a variety of benefits when compared with an oxygen tank. Oxygen cylinders or tanks eventually run out of oxygen. A gauge shows the tank’s oxygen levels. When the tank is empty, an oxygen supplier replaces it. You should always have extra oxygen tanks on hand.2   This means you have to plan carefully, so you do not run out of oxygen, and so you are able to make time to get your tanks refilled or replaced on time. Oxygen concentrators, on the other hand, run on electrical power and thus supply an unlimited amount of oxygen.1   This means that with an oxygen concentrator, as long as you have access to a power source or charged battery, you will never run out of oxygen.

Additionally, oxygen tanks are heavy and difficult to move around, even from room to room. Even smaller “portable” tanks are heavy and unwieldy. Oxygen concentrators, on the other hand, can be quite small, with many portable oxygen concentrator models weighing less than 5 pounds and some home oxygen concentrators less than 20 pounds.  This means you may leave your home with a fully-charged portable oxygen concentrator for hours at a time. Simply put, using a portable oxygen concentrator gives patients peace of mind to leave the home and allows them to experience less dyspnea (shortness of breath) outside the home.

With an oxygen concentrator you will not have to worry about multiple points of contact when refilling or replacing oxygen tanks; you can simply turn your unit on, put your mask on over your nasal cannula and go.  Cleaning and maintaining an oxygen concentrator does not require any special equipment which means you can disinfect your device after going out in public.

How to Use a Portable Oxygen Concentrator

So how does a portable oxygen concentrator work?  As always, read and follow the manufacturer’s directions carefully, but in many cases, you will follow the same basic procedure. Here is how to use a portable oxygen concentrator.

  1. Make sure you have adequate power for your oxygen machine, either via a fully charged battery or an available AC or DC power source
  2. Ensure you have a clean nasal cannula, or mask, and tubing properly attached to the nozzle fitting on your oxygen generator
  3. Ensure your particle filter is properly attached to ensure particles are not drawn into the oxygen machine as they could damage it
  4. Make sure you place the oxygen concentrator in a well-ventilated area (or that your carrying bag allows proper ventilation) as the intake and exhaust must have clear access to work properly
  5. Press the power button and allow the oxygen concentrator to warm up properly to ensure it reaches the correct oxygen concentration levels before use. Your model should indicate when the O2 concentrator is ready for use
  6. Set the portable oxygen concentrator to your prescribed flow rate setting
  7. Place the nasal cannula into your nostrils and over your ears, adjusting for proper and comfortable fit, then breathe through your nose to begin getting oxygen from your O2 concentrator.


Inogen is a medical technology company, a global leader in portable oxygen therapy solutions for patients with chronic respiratory conditions. As a result, we worked to create our compact, lightweight oxygen concentrators, designed for the travel needs of our active patients and their lifestyle. All of Inogen’s concentrators are clinically validated to delivery oxygen 24 hours a day, 7 days a week.  With Inogen, you can have peace of mind while getting the oxygen you need. 

If you’ve been using an oxygen tank system or a stationary oxygen concentrator and you want to learn more about how Inogen products work, read on to learn about the Inogen One G5 or G4 Portable Oxygen Concentrators. You can also explore our Inogen One comparison chart to compare the features of each Inogen One model and get an idea of which model best meets your needs. If you prefer a stationary concentrator for your home, learn below about our stationary oxygen concentrator, the Inogen At Home.


The Inogen One 5 System offers 6 flow settings and delivers up to 1260ml or medical grade oxygen per minute in one of our quietest, smallest and lightest portable oxygen concentrators.   Capable of delivering oxygen 24 hours a day, 7 days a week using our proprietary Intelligent Delivery Technology®, the G5 offers more flow settings and a longer battery life – up to 13 hours with a double battery – than other Inogen models.  Nonetheless, the Inogen One G5 is small and weighs only 4.7 pounds, allowing mobility without needing to recharge as frequently. The Inogen Connect App with Bluetooth System, when used on a supported device, helps you monitor your oxygen use and keep track of your equipment’s functionality.

Our portable oxygen concentrators provide travel portability for a patient’s active lifestyle, plus they meet FAA requirements.  When you purchase an Inogen One G5 System, you will receive a 3-year warranty and a custom carry bag, along with a single battery, DC power cable and AC power supply. Purchase a Freedom Package to receive everything listed, as well as a lifetime warranty and additional batteries.


Designed to be small and compact, the Inogen One G4 portable oxygen concentrator is our lightest and quietest unit available for oxygen therapy.  Weighing only 2.8 pounds, with a standard battery, this portable oxygen concentrator can be used at home and away.  It offers 1-3 flow settings, and with its reliable, pulse-dose based Intelligent Delivery Technology®, the G4 is powered to provide medical grade oxygen delivery all day, every day.

The Inogen One G4 System also includes the Inogen Connect App with Bluetooth System, when used on a supported device, helps you monitor your oxygen use and keep track of your equipment’s functionality. Additionally, you will receive a carry bag, user manual, AC/DC power supplies and your single rechargeable battery with a life of up to 2.7 hours with the standard battery.   Your Inogen One G4 System meets FAA requirements and is covered by a standard 3-year warranty. However, if you choose to purchase one of our three Freedom Packages, you will receive everything listed above, as well as additional batteries and a lifetime warranty.


The Inogen At Home is our stationary oxygen concentrator.  Our energy-efficient, lightweight stationary oxygen concentrator, the Inogen At Home weighs 18 pounds – half the weight of many other home oxygen concentrators currently being used.   The Inogen At Home is energy-efficient, using just 100 watts of energy on Flow Setting 2.  Although this oxygen concentrator provides you with 5 liters per minute continuous oxygen, it is quiet.  If you need a stationary oxygen concentrator, try Inogen’s At Home oxygen concentrator for your oxygen therapy.

Frequently Asked Questions


 Inogen One portable oxygen concentrators do not actually make oxygen. Rather, they pull oxygen from the air surrounding them and concentrate it. To do this, Inogen One Portable Oxygen Concentrators remove nitrogen and other gases, as well as impurities, found in the air to purify it and compress it into medical-grade oxygen. Once the oxygen is sufficiently purifying and concentrated, the Inogen One produces oxygen-rich air, which is then delivered to the user via nasal cannula.


 An oxygen concentrator uses the surrounding atmosphere to create oxygen-rich air by pulling surrounding air into the oxygen machine, compressing it, purifying it and removing nitrogen and other impurities. The purified, oxygen-rich air is then delivered to the patient.2


 While an oxygen concentrator does not generate oxygen on its own, the oxygen is pulled from the air around the oxygen generator. Because of this, there is no danger of running out of oxygen, as long as your oxygen machine has power and access to open air. Simply ensure that you always have a clear air supply, a powered battery and concentrator.1


 Many portable oxygen concentrators are made to be used anytime you need supplemental oxygen. Inogen portable oxygen concentrators incorporate our reliable, pulse-dose based Intelligent Delivery Technology to provide medical grade oxygen delivery all day, every day.  Because your respiratory rates change with your level of activity, each of our Inogen One models responds to your changing physiology by detecting your breathing rate and adjusting the bolus dose. The Inogen One system is clinically proven to effectively deliver the oxygen you need, no matter what time of day it is provided it is connected to an AC, DC or charged battery power source.


While an oxygen concentrator does not require refills or tank replacements like other oxygen delivery systems, it is important to make sure you keep up with your O2 concentrator’s maintenance needs to ensure that your oxygen machine is operating correctly. Proper maintenance also ensures that your portable oxygen concentrator lasts so you can use it for as long as possible. Alarms will typically let you know when replacement parts are required, but it is a good idea to know what to look for before you experience any problems with your oxygen generator. Read your model’s manual for more information, but for general maintenance, you should:

  • Wipe down your oxygen generator once a week to keep it clean from dirt, dust, hair or pet fur
  • Check your particle filters weekly and rinse clean when dirty
  • Change your nasal cannula and tubing regularly, as directed by your provider
  • Inspect HEPA filters and columns (sieve beds) to see if they require changing or replacement
  • Heed all alarms


Inogen offers replacement parts and accessories conveniently on our website. You can order some of the parts ahead of time to keep them on hand, or choose to order as needed. As always, if you have any questions about installing replacement parts, which parts to purchase or any other questions about how to use a portable oxygen concentrator, we are here to help. Contact us for help and information.


  1. Hardavella G, Karampinis I, Frille A, Sreter K, Rousalova I. Oxygen devices and delivery systems. Breathe (Sheff). 2019 Sep;15(3):e108-e116. doi: 10.1183/20734735.0204-2019. PMID: 31777573; PMCID: PMC6876135.
  2. Supplemental Oxygen Therapy: Types, Benefits & Complications (clevelandclinic.org); https://my.clevelandclinic.org/health/treatments/23194-oxygen-therapy


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