Oxygen Refills- Robbed

[dzeleski]

1 minute ago, N201MKTurbo said:

Most of our portable bottles are medical bottles. They can't fill them without a prescription. If you get a prescription, you can get them filled at a medical oxygen company. There are zillions of them. And they are cheap.

It is a medical tank but its not labeled as medical (tank is from mountain high), nor does it have the medical valve. It has the standard CGA 540 industrial valve. Are medical places able to fill the 540 valve? I probably can get a prescription if they can fill it.

[N201MKTurbo]

1 minute ago, dzeleski said:

It is a medical tank but its not labeled as medical (tank is from mountain high), nor does it have the medical valve. It has the standard CGA 540 industrial valve. Are medical places able to fill the 540 valve? I probably can get a prescription if they can fill it.

You would have to call them. I would imagine they can because the big bottles that hospitals have the CGA 540. If not buy your own adapter and see if they will fill it with your adapter.

[dzeleski]

Just now, N201MKTurbo said:

You would have to call them. I would imagine they can because the big bottles that hospitals have the CGA 540. If not buy your own adapter and see if they will fill it with your adapter.

Worth a shot, thanks! Id rather not have to deal with keeping two 150cu bottles just to fill up a 24cu tank a few times a year.

[kortopates]

Where is the requirement for cleaning?
That would require removing the valve each time they are filled, and I don't see gas suppliers doing that.

Go talk to your Industrial gas shop. I’ve observed it and a process i can only describe as vacuuming the cylinder. You don’t remove the valve till hydro time, then at refills it’s cleaned out by a vacuuming process. I don’t but medical O2 but from what the gas shop explains they do this for all breathing gas.

Let’s reverse the question. If they didn’t prepare breathing gas bottles differently from industrial gas why do you folks suppose the shops don’t want to fill a cylinder with breathing gas that’s not marked for ABO or Medical O2? Same O2 after all, but unknown cylinder. The process normally starts with the hydro.


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[GeeBee]

Section 11.4

https://pubchem.ncbi.nlm.nih.gov/compound/Oxygen

"Oxygen is now manufactured in only 2 grades: grade A, aviator's breathing oxygen, and grade B, for industrial or medical purposes. The only difference ... is the permissible moisture content. In high-altitude flying, there is the risk of freeze-up of any moisture present in an oxygensystem ..."

[dzeleski]

1 hour ago, kortopates said:

Go talk to your Industrial gas shop. I’ve observed it and a process i can only describe as vacuuming the cylinder. You don’t remove the valve till hydro time, then at refills it’s cleaned out by a vacuuming process. I don’t but medical O2 but from what the gas shop explains they do this for all breathing gas.

Let’s reverse the question. If they didn’t prepare breathing gas bottles differently from industrial gas why do you folks suppose the shops don’t want to fill a cylinder with breathing gas that’s not marked for ABO or Medical O2? Same O2 after all, but unknown cylinder. The process normally starts with the hydro.


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Mountain High publishes the following:

https://www.mhoxygen.com/348-what-are-the-different-oxygen-types/

Q: Is it true that medical and welder’s oxygen differ from aviation oxygen?
 

A: There are no different grades of oxygen being produced or contained in cylinders under DOT regulations.

Contrary to common myth, medical oxygen contained in a medical cylinder is no different than that contained in a cylinder marked aviators oxygen or otherwise. Furthermore, because of the chemical nature of oxygen it must be as pure and dry from water as possible if stored under pressure. Oxygen is produced to be better than 99.9% pure, if not damage or contamination will result to equipment. Oxygen even holding the slightest amount of water moisture–which is added during delivery for medical and industrial purposes–may have helped to cause confusion in the industry. As far as the FDA is concerned, any oxygen cylinder marked as USP or medical is a drug, and has to be held, dispensed, and used under strict medical protocols outlined by the FDA and cannot be lawfully used for aviation purposes. Oxygen cylinders labeled as AVO, which is aviator’s oxygen, or otherwise is not under the auspices of the FDA and are lawfully used for aviation purposes.

(Reprinted from the Compressed Gas Association)


https://www.mhoxygen.com/2016/wp-content/uploads/5I000-0005-00-Filling-Your-Cylinder-200406.pdf
It specifically states to check that only master cylinders marked as 'AVO/ABO' is used for filling the tanks. It also states that the only difference between the different types of O2 are related to hygiene protocols, handling and inspection.


 

[kortopates]

22 minutes ago, dzeleski said:

It specifically states to check that only master cylinders marked as 'AVO/ABO' is used for filling the tanks. It also states that the only difference between the different types of O2 are related to hygiene protocols, handling and inspection.

This is the entire point. Its all the same dry O2, but any breathing oxygen is dispensed differently from any industrial gas by different protocol if you will to ensure the internal cleanliness of the bottles for breathing. Its starts with the hydro process, or when the tank is labeled and then at refill time, from what I observed, as vacuuming of the tank prior to refill. Industrial gas has no such requirements.

As Rich pointed out, for ABO they also measure moisture content and log it; but this has become superfluous decades ago by virtue of the manufacturing process. But they they still follow the process.

Same O2 but dispensed differently depending on intended use.

Most of what you read on the internet only talks about there only being a single manufacturing process that produces dry O2 which has been true for decades. They don't talk about the different protocols in dispensing breathable O2 versus industrial O2. 

 

[Ragsf15e]

This is too much, I’m getting an oxygen generator/concentrator!  Inogen G5!

[N201MKTurbo]

1 hour ago, Ragsf15e said:

This is too much, I’m getting an oxygen generator/concentrator!  Inogen G5!

FWIW, the oxygen it produces would never pass for ABO...

[PeteMc]

2 hours ago, GeeBee said:

"Oxygen is now manufactured in only 2 grades: grade A, aviator's breathing oxygen,

I see your document was modified in 2023, but it is a crowd sourced document and I do not see a list of edits with dates.  So there's no way to tell what was change or when.  The original Doc was from 2004 and I suppose it was true that they still created different types of O2 back then.  But I do not believe that it is still the case, it's just not worth it for them to make different grades do to the improvements in technology.  They just make one and send it out to the distributors.  

And (can someone confirm??) I think that all O2 is distributed in Liquid Oxygen form and then converted back to Gas at the distributor. 

ADDED: To clarify my last statement...  That means it's ALL the same stuff.  Distributed to ALL as Liquid O2, so there's no way to distinguish one kind from the other.  (Yes, you can test for moisture, but the vast most distributers it's not an issue.)

 

Edited July 10, 2023 by PeteMc

[GeeBee]

29 minutes ago, PeteMc said:

I see your document was modified in 2023, but it is a crowd sourced document and I do not see a list of edits with dates.  So there's no way to tell what was change or when.  The original Doc was from 2004 and I suppose it was true that they still created different types of O2 back then.  But I do not believe that it is still the case, it's just not worth it for them to make different grades do to the improvements in technology.  They just make one and send it out to the distributors.  

And (can someone confirm??) I think that all O2 is distributed in Liquid Oxygen form and then converted back to Gas at the distributor. 

 

Well it is crowd sourced in that there are submissions from the public, but if you read further, the submissions must be reviewed and verified by the National Institutes of Health (NIH) which is why it has an NIH.gov address. You might want to read the submission rules. A N201MKTurbo mentions previously in this thread the only difference between ABO and other oxygen is moisture content. His post is verified by this document from the NIH.  To achieve ABO it is simply run through a dryer of various forms and designs. If the regulator is not subject to sub-freezing temps, it makes little difference, if not it might. Often times (more often than not) the supplier's equipment is sufficient at drying the gas without further treatment to be equal to ABO standards.

[Pinecone]

3 hours ago, kortopates said:

Go talk to your Industrial gas shop. I’ve observed it and a process i can only describe as vacuuming the cylinder. You don’t remove the valve till hydro time, then at refills it’s cleaned out by a vacuuming process. I don’t but medical O2 but from what the gas shop explains they do this for all breathing gas.

Let’s reverse the question. If they didn’t prepare breathing gas bottles differently from industrial gas why do you folks suppose the shops don’t want to fill a cylinder with breathing gas that’s not marked for ABO or Medical O2? Same O2 after all, but unknown cylinder. The process normally starts with the hydro.

If they do not remove the valve, any vacuum applied will only suck out the rest of the gas in the bottle.  And since the valve includes a short radius 90 bend, there is NO WAY to stick something in to vacuum out debris.

[Pinecone]

2 minutes ago, GeeBee said:

Well it is crowd sourced in that there are submissions from the public, but if you read further, the submissions must be reviewed and verified by the National Institutes of Health (NIH) which is why it has an NIH.gov address. You might want to read the submission rules. A N201MKTurbo mentions previously in this thread the only difference between ABO and other oxygen is moisture content. His post is verified by this document from the NIH.  To achieve ABO it is simply run through a dryer of various forms and designs. If the regulator is not subject to sub-freezing temps, it makes little difference, if not it might. Often times (more often than not) the supplier's equipment is sufficient at drying the gas without further treatment to be equal to ABO standards.

 

Except that ALL O2 these days are from liquid oxygen.  If there is any water in the liquid oxygen, it is frozen.

[PeteMc]

19 minutes ago, GeeBee said:

the submissions must be reviewed and verified by the National Institutes of Health

Yes, not disputing that....  But I have no way of knowing when the "Aviator's" O2 comment was added and and what the 2023 change was.  It could have been in the original publication and just never changed.

Also surprised for that type of document there is no change sheet.  It may be there, but I didn't see it.

 

[1980Mooney]

Good description here on Sportys.  You are correct that both ABO and medical oxygen are certified 99.5% pure. However medical oxygen is not certified to the same 0.1% dryness as a ABO.  Welding and industrial oxygen is only certified to 99.2% pure, may not be filtered as well and no dryness certification.

It is possible that all three grade has delivered, and some places are identical due to supply chain consolidation, however, you just don’t get the certification on medical and industrial  

https://www.sportys.com/blog/different-grades-of-oxygen-and-how-they-pertain-to-pilots/

[chriscalandro]

I’ve been filling my own tanks with an oxygen concentrator for a few years now. 
 

when I was curious and tested it it was 98% and dry. 
 

good enough for me. 

Edited July 10, 2023 by chriscalandro

[EricJ]

21 minutes ago, chriscalandro said:

I’ve been filling my own tanks with an oxygen concentrator for a few years now. 
 

when I was curious and tested it it was 98% and dry. 
 

good enough for me. 

What are you using as a concentrator/compressor?

 

[N201MKTurbo]

1 hour ago, 1980Mooney said:

Good description here on Sportys.  You are correct that both ABO and medical oxygen are certified 99.5% pure. However medical oxygen is not certified to the same 0.1% dryness as a ABO.  Welding and industrial oxygen is only certified to 99.2% pure, may not be filtered as well and no dryness certification.

It is possible that all three grade has delivered, and some places are identical due to supply chain consolidation, however, you just don’t get the certification on medical and industrial  

https://www.sportys.com/blog/different-grades-of-oxygen-and-how-they-pertain-to-pilots/

All the oxygen is the same. they don't do anything extra for ABO or medical. It all comes from the same manifold. The truth is the crappiest welding oxygen easily meets the ABO standard. It just isn't tested for it.

[N201MKTurbo]

I have worked on cryo stuff quite a bit in my life. If you take the head off of a large dewar like an 80 liter and shine a flashlight down into it you will see what looks like sand in the bottom. That is the moisture. If you blow into the dewar, the moisture on your breath will freeze into snow like stuff, fall into the liquid and settle to the bottom. This happens every time you take the head off and just about all dewars have some in the bottom.

In a helium dewar the sand is frozen water, frozen nitrogen and frozen oxygen. 

[N201MKTurbo]

MIL-O-27210F.pdf

[PeteMc]

2 hours ago, N201MKTurbo said:

If you take the head off of a large dewar

Okay, you peaked my curiosity.   Are these dewars pressurized?  If so, after the initial release is there a back draw of Air where the moisture then freezes before the interior of the dewar has anywhere close to enough time for the temp to rise to near water freezing level?  Or is the moisture exposed to the super cold, so therefore you get "what looks like sand" at the bottom from the newly exposed Air?

Same question if they are a vacuum, but the answer would seem more obvious.

 

[PeteMc]

1 hour ago, M20Doc said:

From just 3 Mooney maintenance manuals,

Dated 2005....

 

[N201MKTurbo]

15 minutes ago, PeteMc said:

Okay, you peaked my curiosity.   Are these dewars pressurized?  If so, after the initial release is there a back draw of Air where the moisture then freezes before the interior of the dewar has anywhere close to enough time for the temp to rise to near water freezing level?  Or is the moisture exposed to the super cold, so therefore you get "what looks like sand" at the bottom from the newly exposed Air?

Same question if they are a vacuum, but the answer would seem more obvious.

 

Most large dewars will be good to about 100 PSI. They will continuously release pressure because of boil off. Most people want the gas not the liquid, so they just tap the pressurized gas. They have a relief valve so they don't explode. Actually they usually have two. The dewar doesn't need pressure to maintain the liquid. You can release the gas pressure and take the head off. We used to do that because we had superconducting electronics we would insert into the liquid. This assembly would screw on in place of the normal head. The dewar is just a big thermos bottle. It is double shelled with a radiation shield between the two shells. the radiation shield consists of about 10 layers of aluminumized mylar and bridal veil. Ths chamber between is then evacuated to about 10-6 torr. A good dewar will keep 120 liters (well boil off 120 liters) in about 6 months even with the top open. I usually put a Styrofoam cup with a pin hole, in the hole if I leave the head off for any length of time. 

They have dip tubes that go to the bottom. one of the valves on the top is the gas valve and the other is the liquid valve if you want to get liquid out. If you want to get liquid out, you need a liquid line which is an insulated hose. When you open the liquid valve you have to cool the liquid line before any liquid will come out, so it will hiss and sputter for a minute or so until the line is down to liquid temperature.

These have KF fittings on the heads. Some have bolted flange. The black capped stub on the top of each one is where you connect the vacuum pump to pump down the area between the walls. They need to get pumped down every 5 years or so.

[EricJ]

44 minutes ago, M20Doc said:

Still a current Mil spec and still current manuals.  Not much has changes at Mooney.

The parts you highlighted just indicated the expected volumes if ABO was used; I didn't see anything that indicated ABO was required.   I took it to mean that lower O2 volumes would be expected if less pure gas was used, e.g., 1% Nitrogen or something.

Much of the crew related O2 regulation is from the DOT, not as much from the FAA.

[zehutiman]

On 7/8/2023 at 9:02 PM, A64Pilot said:

 

We had an O2 concentrator on the AH-64, it took the O2 and dumped it overboard and filled the fuel tanks with the O2 depleted air, Nitrogen to prevent fuel tank explosions 

https://www.army-technology.com/news/newscobham-modernise-us-apache-units/

Seems like the Boeing 787 does too?

I believe all airliners now have Nitrogen-generation sysytems.