What's the Difference between an Oxygen Concentrator, Compressed Oxygen, and Liquid Oxygen?

Whats the Difference between an Oxygen Concentrator, Compressed Oxygen, and Liquid Oxygen?


There are about 16 million people in the United States alone who have chronic obstructive pulmonary disease (COPD). This condition is characterized by slow but persistent lung function decline that leads to breathlessness, chest pain, and fatigue. Several lifestyle changes can significantly reduce the rate at which COPD progresses including an improved exercise routine, a refined diet, inhaled medications, and most importantly, oxygen therapy. Every case of COPD is different, however, so patients should consult with their doctor to learn which lifestyle changes will benefit them.



When it comes to supplemental oxygen therapy, there tends to be a lot of confusion over the different devices that are available to COPD patients. Many people are told that they need medical oxygen, but they’re never provided with instruction on finding an oxygen device that meets their needs. In this post, we’ll discuss three different types of medical oxygen: compressed oxygen, liquid oxygen, and oxygen concentrators. You’ll learn the differences between them and you’ll receive some guidance for choosing one that fits your lifestyle.


If you still have questions after reading, be sure to reach out to our oxygen device specialists here at LPT Medical. We’ll walk you step-by-step through choosing an oxygen device, getting the best deal, and even helping you to receive the necessary medical paperwork. Give us a call at 1-888-416-3855 or email us at info@lptmedical.com.


What is Compressed Oxygen Gas?

Compressed oxygen gas refers to oxygen that has been stored within a tank or a cylinder. Oxygen has been stored in this way since 1868 and it’s still considered a viable method to this day; albeit, the technology has certainly evolved. Compressed oxygen gas is used for a variety of purposes, but it’s primarily used for industrial and medical settings. Many COPD patients use oxygen tanks on a daily basis to maintain the oxygen levels in their blood. For the most part, oxygen tanks are reliable for oxygen therapy, but there are some downsides that you should be aware of.


Oxygen tank

One of the most notable downsides of oxygen tanks is that they are heavy and bulky. Chances are, you’ve seen people carrying an oxygen tank around in public, and it’s not hard to see how much they struggle. Portable oxygen tanks can weigh as much as 20 pounds and they have a very oblong shape that makes them difficult to carry at your side or on your back. Most people choose to put their oxygen tank on a rolling cart but this comes with problems of its own. They take up a lot of space and they’re difficult to maneuver around obstacles or up a flight of stairs. Home oxygen tanks can weigh well over 100 pounds meaning you will need professional help just to move one.


oxygen tank


Another glaring problem with oxygen tanks is that they need to be refilled constantly. For example, an “E” tank that is about 3 feet tall and weighs 8 pounds will only last 5 hours if it’s used continuously. At this point, you are going to either have to run home and use your home fill station or find a dependable oxygen company that can refill or replace your oxygen tank for you. All of this takes time and money, all while distracting you from what you care about most. It’s important to remember that the only way to extend the duration of your oxygen supply is to carry a bigger and bulkier oxygen tank or purchase a device called an oxygen conserver.


What is Liquid Oxygen?

Liquid oxygen is similar to compressed oxygen in that the oxygen is stored in a tank. The difference is that these devices store the oxygen in its liquid state rather than as a gas. This is preferable over compressed oxygen because once oxygen enters its gaseous state it expands and thus takes up more space. Liquid oxygen canisters tend to be much smaller and lighter than compressed oxygen and they last longer without needing to be refilled. There are some downsides to these units, however, so let’s take a look.



Likely the first thing you’ll notice about liquid oxygen devices is that they are more expensive than traditional oxygen tanks. This is because — in order for oxygen to be stored in a liquid state — it needs to be kept at very low temperatures. And in order to do that, you need a special type of storage container. Liquid oxygen cylinders work like a thermos in that they keep the liquid oxygen at around -297 degrees Fahrenheit. For safety reasons, liquid oxygen cylinders have decompression vents that release oxygen as the unit warms up. This means you should use it right after filling it up to ensure no oxygen is lost.  


Oxygen face mask


One of the problems many people encounter with liquid oxygen is that it’s extremely difficult and expensive to refill. You’ll need to either have a special home fill reservoir or you’ll need to outsource to an oxygen company. Even then, you may be hard-pressed to find a company that is able to fill a liquid oxygen device. While liquid oxygen tanks provide many benefits over traditional oxygen tanks, they aren’t as popular simply due to the high barrier of entry. 


What is an Oxygen Concentrator?

The third and final oxygen device we’ll discuss is oxygen concentrators. Unlike traditional and liquid oxygen tanks which hold oxygen inside the unit, oxygen concentrators draw in ambient air, remove gases like nitrogen and argon, and output medical-grade oxygen. Another thing that sets concentrators apart is that they are electronic devices. What this means is that they need a reliable source of energy in order to operate. There are three different types of oxygen concentrators so we’ll break each one down.


Stationary Oxygen Concentrators

Also called home oxygen concentrators, stationary oxygen concentrators need a constant source of power in order to operate. The unfortunate downside to this is that you won’t be able to leave the house without there being an interruption in your oxygen delivery. On the other hand, you can still use things like extension cords or extra long nasal cannulas in order to move around the room freely. Despite the name “stationary,” most of these oxygen devices have wheels on the bottom that make them easier to move around the house. However, they tend to weigh a lot (usually upwards of 30 pounds). 


NewLife Intensity 10


One of the main reasons stationary oxygen concentrators are still in use today is because of their high oxygen output. Some concentrators like the NewLife Intensity 10 can put out up to 10 LPM (liters per minute) of oxygen which is enough for people with severe COPD. They’re also extremely reliable and they can run 24 hours a day and 7 days a week without a problem. Stationary concentrators are not ideal for people who want to get out and about but they’re a good choice for people who stay around the house. 


Continuous Flow Portable Oxygen Concentrators

A portable oxygen concentrator works the same way as a stationary oxygen concentrator, but instead of being plugged into a wall outlet 24/7, POCs run off of rechargeable batteries. Most POCs use lithium-ion batteries which are some of the most powerful and reliable batteries in use today. You can find them inside cellphones, laptops, and other electronic devices. The term “continuous flow” refers to the way that oxygen is administered to the patient. It simply means that the oxygen is being released in a constant stream regardless of your breathing rate.




As you can imagine, there are several disadvantages to this. Since the device is working around the clock to administer oxygen, your battery life is going to suffer. Most continuous flow concentrators will only run for a couple of hours before the batteries need to be recharged or replaced. This can really be problematic if you want to get out of the house for an extended period of time in order to visit a friend or take a vacation. 



Since continuous flow units are so bulky, taking your oxygen device into public areas or walking up long flights of stairs is out of the question. Unless you’re able to carry the machine on your back, the nasal cannula will dangle down quite a bit which can be a tripping hazard for you and others. To mitigate this risk, some people resort to using mobility aids that they can rest the device on while walking. This way, there’s no chance that the oxygen tubing will get caught on anything. The obvious downside of this is that you’ll have yet another thing to keep track of as you’re out and about.


Pulse Dose Portable Oxygen Concentrators

The final type of oxygen concentrator is a pulse dose portable oxygen concentrator. The term “pulse dose” refers to the way that oxygen is administered to the patient. Rather than being released in a constant stream, the device closely monitors your breathing rate and only delivers oxygen at the optimal moment. What this means is that no oxygen is wasted and you’ll have a lot more battery life to work with. Another major benefit of this technology is that it enables manufacturers to make their devices much lighter and smaller.


FreeStyle Comfort


The Caire FreeStyle Comfort is one of the top pulse dose portable oxygen concentrators currently on the market. It weighs in at just 5 pounds and the 16-cell battery lasts up to 8 hours on a setting of 2. It also has a maximum oxygen output of 1,050 ml/min which is more than enough for the vast majority of oxygen patients. The great thing about the FreeStyle Comfort and most other pulse dose POCs is that it’s approved by the Federal Aviation Administration (FAA) meaning you’ll be able to take it on any commercial airline with you.   


Zen-O Lite

Ultimately, using a pulse dose portable oxygen concentrator as opposed to one of the other oxygen devices listed above, you’ll have more freedom to go where you please and spend more time doing the things you love. They’re very simple to use straight out of the box so you don’t have to worry about spending hours reading through the user manual or researching online. There is also a wide range of accessories available for them in order to help you customize and make the most of your new device.



In this post, we took a look at three of the main oxygen devices on the market: oxygen tanks, liquid oxygen tanks, and oxygen concentrators. Each of these devices is widely used by oxygen patients across the world and they are each viable in their own way. However, all things considered, pulse dose portable oxygen concentrators provide some pretty distinct advantages over the other options. Most importantly, they’re extremely lightweight meaning you can take them anywhere in the world with comfort and ease.



The GCE Zen-O Lite, for example, is a pulse dose portable oxygen concentrator that weighs in at just 5.5 pounds. With both batteries inserted into the device, you’ll get up to 8 hours of battery life on one charge! That’s enough to last you the whole day and then some. It’s also one of the most powerful pulse dose units offering up to 1,050 ml/min (milliliters per minute ) of oxygen on one charge.


There are many incredible pulse dose concentrators on the market, so be sure to contact our respiratory specialists to discover which one is best for you. We’ll walk you through the whole process from choosing a device to choosing a buying option. We’ll even help you collect all the necessary paperwork and assist you with being reimbursed through Medicare or another health insurance company. Give us a call at 1-(800)-946-1201 or email us at info@lptmedical.com to get started.

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