How to Refill Oxygen Tanks

Updated February 17, 2017

Home oxygen therapy is an attractive option for patients who need oxygen assistance but aren't ill enough to stay in the hospital. Patients with asthma, emphysema, chronic bronchitis, lung cancer or other conditions that cause difficulty breathing can all benefit from home oxygen therapy. A doctor prescribes the oxygen, including the kind of oxygen assistance and the rate of flow. Then, a home oxygen supplier comes to the home on a regular schedule and refills the oxygen tanks. Liquid oxygen is growing in popularity because it does not require electricity, unlike compressed oxygen.

Check the patient's tank for air leaks and liquid leaks at all pipe connections. If the tank has signs of leaks, do not attempt to fill it; use a different tank.

Clean the hose coupling on top of the patient's tank, as well as the coupling on the hose, to make sure there is no dirt or moisture. Dirt or moisture can cause liquid entering the tank to leak or spray, which can cause injury or cause the coupling to freeze; the coupling may not be able to release the hose.

Open the liquid release valve on the master dewar (the primary holding tank).

Attach the hose from the dewar to the patient's tank via the hose coupling.

Open the pressure release valve on the patient's tank. The dewar will now begin to gravity feed the patient's tank.

Keep eye on the patient's tank pressure; follow the manufacturer's instructions on pressure settings for the tank.

Once the tank is filled, liquid will begin to spurt from the pressure release vent on the patient's tank. Shut off the main valve on the dewar, close the pressure release valve on the patient's tank and remove the hose.

Check patient's tank for pressure, air and liquid leaks. It leaks are present, do not give the tank to the patient. Leaking tanks can cause an over-saturation of oxygen in environmental air, which can cause headaches and high blood pressure. If the oxygen saturation gets very high, it can cause open flames, such as from the stove, matches, lighters, candles and cigarettes, to ignite and cause injury to the patient.

Reattach all of the hoses to the tank and set the patient's prescribed oxygen litre flow, and continue the oxygen therapy.


Liquid oxygen is very cold. It will cause instant frostbite. Do not touch the oxygen when it is in liquid form. Do not allow the oxygen to become over-saturated and leak into the patient's home or it will present a fire risk.

Things You'll Need

  • Dewar
  • Patient's tank
Cite this Article A tool to create a citation to reference this article Cite this Article

About the Author

Natalie Smith is a technical writing professor specializing in medical writing localization and food writing. Her work has been published in technical journals, on several prominent cooking and nutrition websites, as well as books and conference proceedings. Smith has won two international research awards for her scholarship in intercultural medical writing, and holds a PhD in technical communication and rhetoric.