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02 Bottles

Old 25th May 2014, 02:48
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02 Bottles

Is it true that an O2 bottle thats being used must remain above 50 psi. In that as the psi gets below 50 the oxygen can become contaminated/poisonous. Also at low pressures the inside of the bottle is more prone to corrosion.

Does aviation oxygen that stored in a bottle at the correct pressure have a shelf life. Ie if you dont use it all and refil it, do you have to periodically discharge the oxygen and recharge with fresh O2?
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Old 25th May 2014, 03:06
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Question Oxygen

That's just over three bar pressure,Not sure about oxygen being corrosive as its pure oxygen in the bottle but at that pressure in a small bottle you don't have much time left!On scuba tanks a return to the surface is advised at about 35 bar (500psi).I experienced an empty tank once and can tell you that at first you wonder why its difficult to breath!Then as you look at your pressure gauge it sinks in that the bottle is empty!!Tanks are tested every five years and if they fail then a hole is drilled in it so it cannot be used.I don't think corrosion would be a problem as breathing oxygen would be dry ?
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Old 25th May 2014, 03:20
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Px needs to be in the bottle to stop corrosion. Meaning that atmos air can't enter the bottle while it contains px. Don't let it go below 50psi. Just go into most shops they will have berating oxy might cost you international breathing oxy fill cost of a carton.
If it's has no px they more than likely will not fill it.
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Old 25th May 2014, 04:03
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yr right is on the money. 50 psi and above for most bottles is a refill. Below 50psi requires a process known as scrubbing and/or a corrosion check.

All bottles have a manufacturers overhaul life which includes a regulator service or overhaul and a full purge and internal corrosion check.This obviously covers refilling the cylinder with fresh oxygen.The overhaul period is normally 5 years but it is spelled out by the manufacturer of the bottle

If anyone doubts the need for these procedures which could if ignored result in an exploding bottle, look up the Qantas incident near Manilla. Bottles only explode for ,corrosion, fire, cracking or fatigue.

Now that oxygen is B1 license, rather than a B2, it will be interesting to see if there are any changes to the oxygen accident rate.


Wunwing

Last edited by Wunwing; 25th May 2014 at 05:20.
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Old 25th May 2014, 07:09
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the stuff of life....

for FLs air survey bottles our were filled with "medical dry breathing oxygen".

You needed then, if to DIY to have the connectors and gauge units to do the refill. ...and keep everything meticulously clean....and free from any oil contamination. Or else !!!!

I have never heard of low pressure making things toxic

Bottles do need regular check ups for corrosion, servicability etc.

Breath easy !


ps arent scuba bottle refilled with just air??
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Old 25th May 2014, 07:28
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02 Bottles

Yep - SCUBA tanks are most definitely compressed air rather than Oxygen. Because you only breathe a little, pure O2 in the air, you don't need much. Underwater, you need much more volume in the form of air which only contains around 9% (from memory) of Oxygen. Hope that explains it....
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Old 25th May 2014, 07:32
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Medical breathing oxy is the exact same as aviation breathing oxy just a different code. Scuba is not the same as the previously listed. There bottles are filled via a high px composer with filters. And is not controlled so it can't be used. Hang a carton get it done in a shop.
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Old 25th May 2014, 15:49
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Oxygen and SCUBA tanks

Air (just plain, ordinary air) is about 21% Oxygen, 78% Nitrogen, and 1% "other gasses." That's pumped into SCUBA tanks as is, for "normal" diving. Most of the better dive shops can add other gasses as needed for special purposes.

Oxygen has been extracted by the cryogenic process for about the last sixty years. Since it is dirt cheap to do it this way, and the process itself guarantees purity far beyond any requirements, it caught on, quickly replacing all previous methods. No other process has been used industrially for that period of time, worldwide.

Previously there were several ways to do it, but all are very expensive, and produce varying quality.

Speaking of quality, there are three levels (in the USA), leftovers from the days before the current process.

Welding Oxygen: By far the most demanding requirements, due to the often used special gasses used in welding, and the extreme purity needed to avoid flaws in the welding. ALL oxygen meets and greatly exceeds these requirements.

Medical Oxygen: The MINIMUM REQUIREMENTS are far lower. Moisture is added at the distribution point (often the bedside) with "Bubblers."

Aviator's Breathing Oxygen: The lowest requirements of all.

The term "Aviator's Breathing Oxygen" has been archaic for more than half a century, and as far as I know, it has now been eradicated from ALL Federal Regulations in the USA. It is now just "Oxygen."

Yes, there are distribution companies who will certify "Oxygen" as ABO, for a substantial additional cost. The oxygen is the same. There are NO additional tests.

I kept a large tank of "welding" oxygen in my hangar, and refilling my airplane tank was quick and easy, and the cost was pennies per fill.

Now, I'm sure CASA would toss you in jail for this, but that is a CASA thing, not based on science. My sympathies.

Best...
John Deakin
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Old 25th May 2014, 23:33
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BOC medical and aviators is the same just a different decal


cheers
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Old 26th May 2014, 05:45
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The big difference between normal oxy cylinders and aircraft cylinders is that aircraft units are designed to be as light as possible.As a result they are very susceptable to corrosion (internal or external) or damage including scoring.

Those who think that you can go the cheap way and ignore the rules are sooner or later going to find out what happens when one goes off. When it does it is not pretty. I worked for a time just on aircraft oxy cylinders and systems and saw a couple go off and one burn.I dont want to be around another one thanks.

Wunwing
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Old 26th May 2014, 07:36
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Air ambos lost a queen air many years ago at dubbo from oxy fire Aircraft burnt to the ground.
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Old 26th May 2014, 12:02
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If memory serves me correctly it was one of the Queen Airs owned by East West and leased by the aero med service of NSW Ambulance Service, I was en route to Bathurst at the time and passing through ... Can't remember what was the cause though.
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Old 26th May 2014, 12:19
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more impotently use it if you fly long legs at 10,000 or there abouts and if you fly at night, especially above 5,000' at night.

I always use it at night and have found the benefit to be significant.

John Deakins article on avweb is worth reading http://www.avweb.com/news/pelican/18...l?redirected=1
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Old 26th May 2014, 12:28
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As I recalled it was parked up and had an oxy leak some how ignited maybe grease and burnt to the ground. Thought it was at dubbo but may be mistaken

Cheers
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Old 26th May 2014, 12:33
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Jaba,

I don't think I'm impotent, but I have been tired at the end of a 6-7 hour day at A100. I am a smoker of course. Just can't keep the dammed things alight above F140, unpressurised.

I can remember sniffing a little hospital grade N2O to get over a hangover, much better than O2.
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