Portable Oxygen: A User's Perspective
The information here provided is for educational purposes only and it is not intended, nor implied, to be a substitute for professional medical advice. Always consult your own physician or healthcare provider with any questions you may have regarding a medical condition.
|Compressed Oxygen||Liquid Oxygen
|B (or M6)
|C (or M9)
|Avg. Weight (lbs.)*
|Avg. Durations @ Setting
| Cont. Flow
| Pulse Flow**
case, spare batteries and a wrench, as required.
**Assumes a breathing rate of 20 bpm.
For me, there is a definite advantage to liquid oxygen. My lifestyle and work take me away for many hours at a time. Using the Helios (image) gives me "portablility." I use an oxygen unit the size of a canteen that weighs less than 4 pounds, which hangs from my waist. The Helios lasts me more than 8 hours, depending on my setting and breathing rate. I also carry the Stroller (image) as a back up, which gives me up to 6 Lpm continuous flow when I need it for exertion. This combination of tanks gives me up to 15 hour away from my 50' tether and the reservoir.But liquid oxygen has a characteristic that bottled oxygen does not. Like dry ice, it evaporates. Left overnight, a liquid portable can lose a half liter of oxygen. On the other hand, a cylinder of compressed oxygen may be used day after day, until it is empty. Liquid oxygen users are dependent on having at home or in their vehicles liquid oxygen reservoirs from which they can periodically refill their portable tanks.
COX- Compressed at 2,000 to 3,000 psi, can turn into a missile if severe damage occurs to its valve. Store cylinders securely in an upright position.On Evaporation
LOX- Stored at 20 psi, its primary danger is causing burns when the fill valves are touched after filling. Also, liquid oxygen continuously vents, so it should always be in a well ventilated area.
BOTH- require safe handling and have the same dangers regarding fire. For more information on safety, see Safety .
COX- Compressed oxygen does not evaporate. If the contents gauge shows a cylinder to be half full and you close the cylinder valve, then the gauge will still show it is half full a day or two later.On Replacing or Refilling
LOX- Liquid oxygen evaporates--in small portables at a rate of between 1 and 1.5 lbs. per day. Since these portables contain only 0.8 to 1.6 lbs. of liquid oxygen when full, you can expect your portable to be depleted in 24 hours, whether you use it or not. Oxygen in a reservoir will deplete at a rate of about 3 lbs. per day.
COX- Replacing an empty cylinder with a full one requires agility with the hands and arms. For this reason the user should be connected to another source of oxygen while performing this task.On Surprises
LOX- The user can remain connected to and receive oxygen from the portable while it is filling.
COX- After replacing an empty cylinder, the user discovers the replacement has a defective valve and is empty. Be prepared with another replacement.On Replacement or Fill Procedures
LOX- After filling a portable, the user discovers the portable has frozen and does not produce oxygen. Learn to fill so the portable does not freeze up. If not, be as prepared as the COX user.
COX- To replace an empty cylinder, close its valve with a wrench, unscrew and remove the conserver from the neck of the cylinder, and move the depleted cylinder out of the way. Move a full cylinder in its place, place the conserver over the neck of the cylinder then screw it in place, and open the cylinder valve.On Operating Positions
LOX- To fill a liquid portable, place the portable on the reservoir, press down on the portable, and lift its valve. When full, close the valve and remove the portable.
COX- Portable systems with electronic conservers will operate in any position. Some pneumatic conservers operate most effectively when the cylinder is vertical. For more information, see Pneumatic Conservers .On Appearance
LOX- Most liquid systems will operate in a limited number of positions--on its back to vertical, but not on its side or upside down.
COX- Most units are contained in bags and do not draw attention.On Conservation
LOX- At high flow rates and under humid conditions, a unit will produce noticeable "smoke," snow, and condensation.
COX- Most users systematically start the day by using their partially filled cylinders because they do not want to appear wasteful by returning partially filled cylinders for refill. Such dedication impacts how these users organize the backups they carry with them.The argument about which is best--compressed or liquid-- has gone on for decades. The important thing to know is that both can support you equally well when you are properly fitted to a system at a prescribed flow rate. If you have any questions about how well oxygen supports you, you should speak with your physician or oxygen provider.
LOX- Users recognize that liquid oxygen will dissipate from both their portable and reservoir whether they are used or not. Knowing this, they will never partially fill their portables. They will begin the day by filling their portable and refilling them as needed.
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