Ok... here's the skinny..
My frame of reference: Paramedic for 15 years, RN for 6. I've worked
with "cascade" filling systems for 10 of those years in my capacity as a
firefighter.
As someone else said: this has been hashed out before. I'm sure I've
posted lots of detail on this in the past. Some new info tho.
All the oxygen comes from the same source. Gas plant makes it by
liquifying air then distilling the fractions. Its then either shipped
liquid, or vaporized and compressed and shipped in tanks. AFTER its been
distilled and packaged its then labelled. Again.. its all from a common
source and spec.
Up until about 8 years ago I used to refill my own (employer's) portable
medical oxygen tanks (D and E cylinders) from H and M size cylinders. At
that time, some agency interjected themselves in the process (FDA??) and
increased the regulatory requirements for medical oxygen. To be sold as
medical oxygen, the tanks must be numbered so they can be tracked. Upon
empty return, the tanks must be taken down to a vacuum, THEN refilled.
This has essentially ended the LEGAL practice of refilling and
dispensing MEDICAL oxygen containers by the end user. They all get
filled and sealed up the distribution chain.
Aviation oxygen and Welding oxygen do not have these sort of inventory
and vacuum requirements. They also dont have the cost associated with
it. Truth is, now, at the vendor level, the medical oxygen will cost
more than the others.
I priced this not too long ago, and the gas vendor I talked to quoted me
something less than the aforementioned $40, and tank "rental" was $2
month for the non-medical oxygen and $5 month for the medical. You haul
the tanks back and forth and exchange empty big cylinders for full. THEN
you just have a hose and pigtail put together to do your own filling.
Get a 2-bottle "welders cart" and you can put two cylinders on a wheel
around cart and refill your oxygen system MANY times for the cost of the
$40 you spent (not counting startup equipment costs, which should be
about $100 for some high pressure braided hose and fittings).
The "downside" of non-medical oxygen is that if the tank is run
completely dry, to atmospheric pressure, then there is the risk that
contaminants in the air will be drawn into the tank if it's LEFT open to
air. These contaminants can then be placed under pressure and inhaled
later. Marginal to minimal risk, but present nonetheless.
So.. can you do it? Well. I WILL. I already have the rig planned, and
the vendor chosen. I will have the spec sheet on all gas I take delivery
of, and I will make sure it meets the requirements of "aviation oxygen".
I wont be providing it commercially. It will be for private use. And I
plan on a big enough system that I wont be needing to fill it away from
home. I have a bottle from a firefighter's breathing system that is
fiberglass wrapped aluminum. It weighs HALF of what an alum E cylinder
weighs and has double the capacity.
If you plan on doing your own fills, its not rocket science but IT CAN
HURT/KILL YOU if you dont pay attention. Get the vendor to show you the
proper way to transfill. Make a "filling station" out of steel pipe.
Take your time - go slow. ABSOLUTELY NO GREASE OR OIL ANYWHERE near the
valve, fittings or couplings. It will be a BAD DAY if you dont heed the
last one.
Dave
Bruce McFadden wrote:
Santa's wife has decided that she would prefer that I fly with oxygen
even below 12.5K and especially at night. So I've been given a tank et
al. I was shocked today when I had it filled at Merucry Air. It is a
415 L size D tank. Because the pressure in their filling tanks were a
bit low, they could only fill my new tank to 1700 lbs, not to a fully
topped off level of 2000 lbs.
They charged me $40 flat fee..... a discount they said because it is a
small cylinder. That seem really steep to me.
Is this about right fur filling an O2 tank. I've heard that it is OK to
have the tank filled at other places such as with medical O2 or welding
O2. Is that OK?
Bruce McFadden Birmingham, AL
PA32-260 N5594J
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