The air that we breathe contains 21 % oxygen, 78 % nitrogen, 1 % of rare gas (mainly argon). The oxygen perhaps delivered starting from 3 different sources :
- O2 out of gas shell,
- O2 concentrators (extractors),
- liquid oxygen, which is nevertheless little used.
On the medical level, there is no reason to prefer a source of oxygen rather than another, delivered O2 having same therapeutic qualities whatever is the source.
It is thus on technical bases, of comfort and cost which one will choose a source rtaher than another and not on strictly medical criteria since oxygen is the same one, whether it comes from a concentrator, bottle of O2 or liquid O2.
Principles and description of the material Gas O2 is presented in the form of bottles (shell) of various capacities. They are always painted in white (what differentiates them from industrial O2).
In these bottles, O2 is stored in gas form and is compressed with a pressure of 200 bars. By way of comparison, this pressure is 100 times higher than the pressure of inflation of a car tire (around 2 bars), that’s why the use of bottles needs precautions.
Thanks to this pressure, O2 gas volume that can release the bottles is significant :
- 3000 litres or 3 m3 for the large bottles, (15 litres in water capacity),
- 1000 litres or 1 m3 for the average bottles, (5 litres in water capacity)
- 400 litres for the small bottles, (2 litres in water capacity),
Autonomy (in hours) of the gas oxygen bottles according to the flow
(litrages expressed in water capacity)
Flow | 2 L | 5L | 15 L |
1 L/min | 6h40 | 16h40 | 50h |
2 L/min | 3h20 | 8h20 | 25h |
3 L/min | 2h13 | 5h33 | 16h40 |
4 L/min | 1h40 | 4h10 | 12h30 |
5 L/min | 1h20 | 3h20 | 10h |
According to the O2 flow prescribed and the capacity of the bottle, this one is emptied more or less quickly. You will find, above, the approximate durations in hours for some flows according to the type of the bottles.
Oxygen extractors or concentrators
Principles and description of the material These machines are presented in the form of a small piece of furniture on casters and weigh 20 to 30 kg. They are connected on the normal electrical supply network.
Whatever their mark, all the apparatuses have the same principle of operation. From the ambient air: oxygen is separated from nitrogen, it exists still 3 % of perfectly inoffensive argon.
The ambient air is compressed thanks to an electric motor. It passes then in a cylinder seals containing a special matter: the zeolite which has the property to retain nitrogen and to let pass oxygen. The unit rolls and zeolite is called sieve.
At the exit of the apparatus, the gas is very enriched out of oxygen. The oxygen teneure is higher than 95 % for flows active until 5 L/min.
Advantages of extractor :
- It is a permanent source of oxygen
- Easy use. There is only the flow to regulate.
- the obstruction is less than the oxygen bottles.
- displacement is easy thanks to the casters of the machine.
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The extractor exempts constraints of delivery of the bottles and of their storage. -
The extractor costs much less to use than bottles of oxygen which one must discharge expenses of hiring and filling.. Indeed only the cost of purchase of the machine is to be entered and weak cost of electricity.
- It is low noise (approximately 43db)
- The obstruction is relatively important for transport. An extractor can nevertheless be put easily in a car.
It will be retained that it is in term of cost that the concentrator is distinguished from the bottles. Also, the veterinary surgeon will be able to make more oyxgénopthérapies because those will be free out of gas.
To see comparative price enters them bottles of O2 and the concentrator of O2 for the volatile anaesthesia and oxygen treatment
