O2 filling

On Wed, 14 Nov 2007 19:46:39 GMT, Viperdoc wrote:

You could get a prescription and then use a medical bottle

I distinctly remember reading that medical O2 was not acceptable (legal?)
for aviation.

Something about the humidity being too high and freezing in the valve.

--
Dallas

On Wed, 14 Nov 2007 17:39:19 -0600, Dallas wrote:

I distinctly remember reading that medical O2 was not acceptable (legal?)
for aviation.

Never mind.

(I did read or hear someone say that... but it appears to incorrect.)

Here's a good article:
http://www.avweb.com/news/pelican/182079-1.html


"Oxygen is oxygen. It is the substance that matters, not the intended
purpose. These days, welding, medical, and aviation oxygen are exactly the
same. All three come from the same tank of liquid oxygen (LOX). The
liquified form is the cleanest, purest, driest form of oxygen (or any
substance) you'll find anywhere."


--
Dallas

"Dallas" wrote in message
...
On Wed, 14 Nov 2007 19:46:39 GMT, Viperdoc wrote:

You could get a prescription and then use a medical bottle

I distinctly remember reading that medical O2 was not acceptable (legal?)
for aviation.

Something about the humidity being too high and freezing in the valve.

--

That's always been my take on it to Dallas, per our suppliers. Medical and
industrial are filled from the same source. Aviation is essentially the
same, but has to be dryer to avoid freezing in extremely low temps.

Precautions taken to avoid impurities in the filling process might differ.
But I bet there are some industrial OX users that are pretty picky about
getting clean pure OX as well. Not everyone just uses it simply for welding
and cutting.

Dallas schrieb:

"Oxygen is oxygen. It is the substance that matters, not the intended
purpose. These days, welding, medical, and aviation oxygen are exactly the
same. All three come from the same tank of liquid oxygen (LOX). The
liquified form is the cleanest, purest, driest form of oxygen (or any
substance) you'll find anywhere."

Sure. But you don't care about the oxygen in the manufactorer's tank,
it's the oxygen in the bottle that you care about. It's the filling
process which makes all the difference.

Maxwell schrieb:

But I bet there are some industrial OX users that are pretty picky about
getting clean pure OX as well. Not everyone just uses it simply for welding
and cutting.

For those applications, the manufactorers offer *really* pure oxygen,
which happens to cost even more than aviation O2.

On Nov 14, 3:52 pm, "Maxwell" wrote:
"Dallas" wrote in message

...

On Wed, 14 Nov 2007 19:46:39 GMT, Viperdoc wrote:

You could get a prescription and then use a medical bottle

I distinctly remember reading that medical O2 was not acceptable (legal?)
for aviation.

Something about the humidity being too high and freezing in the valve.

--

That's always been my take on it to Dallas, per our suppliers. Medical and
industrial are filled from the same source. Aviation is essentially the
same, but has to be dryer to avoid freezing in extremely low temps.

Precautions taken to avoid impurities in the filling process might differ.
But I bet there are some industrial OX users that are pretty picky about
getting clean pure OX as well. Not everyone just uses it simply for welding
and cutting.

According to the gas company I spoke with, all 3 grades of O2 come
from the same source. Medical O2 adds the moisture after the O2 comes
from the bottle (to avoid drying people out). The difference
(according to the gas company) is the certification. When they fill an
aviation bottle they must test it for use in aviation. That test
results in a certification of the O2 in the bottle. I'm not sure if
the FBO's do that or if they are somehow able to certify their main
bottles.

-Robert

On Nov 14, 12:15 pm, "Robert M. Gary" wrote:
With FBOs now charging $50-$100 to fill a tank I've started calling
around to see where else I can get O2 in the Sacramento area.
....cut...
-Robert

At Providence (KPVD) earlier this year they wanted $150 to fill my
little portable tank!!

Cary

On Nov 14, 2:33 pm, Stefan wrote:
Robert M. Gary schrieb:

Do Scuba guys use O2? I thought they used air?

Of course they don't breath pure O2. However, some "advanced" divers
sometimes don't just use compressed air, but their own mixture. Even
more advanced divers sometimes use apparati which mix pure O2 with
whatever they want on the fly while under water.

So a specialized scuba shop might be able to provide you with pure O2.

I happened to visit a SCUBA shop the other day, and can confirm that
they do have bottles of oxygen and compressed air - and the facilities
for mixing them as desired. See the comment on Nitrox elsewhere in the
thread. Since the O2 is for breathing apparatus I doubt that they
would have any reservations about fillling an aviation bottle from
their supply.

David Johnson

Dallas wrote:


Something about the humidity being too high and freezing in the valve.


THIS IS PURE BS.

There is essentially NO moisture in the tank of medical oxygen - for the
same reasons there is no moisture in aviation or welders oxygen. Any
moisture or humidification in a medical stream is added at the point of
use, AFTER the flowmeter.

Any doctor, nurse, paramedic, EMT, respiratory therapist or gas vendor
can vouch for this.

Dave

Robert M. Gary wrote:
When they fill an
aviation bottle they must test it for use in aviation. That test
results in a certification of the O2 in the bottle. I'm not sure if
the FBO's do that or if they are somehow able to certify their main
bottles.

-Robert

The test is done at the gas plant where the bottles are filled. If the
whole batch passes, the tanks pass too. The FBO's involvement is getting
the bottles delivered by the vendor, using the bottles, and having the
bottles picked back up by the vendor.

Medical Grade handling changed about 10 years ago. Now exhausted medical
bottles are sucked to vacuum to remove any possible contamination. Then
they are filled at the gas plant. The bottles have serial numbers. There
is record keeping. This adds to the cost. From $2/month bottle rental to
$10/month bottle rental.

Before 10 years ago, filling a medical bottle was no different than
filling a welding bottle or filling an aviation bottle. You hooked up,
you filled, you went and used it.

If you NEVER let the small bottle go completely empty, and keep what the
medical industry called a "safe residual" pressure (200 psi)in it,
contaminants would never enter the system. The whole change in medical
bottle handling was to fix a "problem" that was caused by misuse in the
first place, and really wasn't a problem in the first place if you
didn't leave an empty bottle OPEN to atmosphere for days on end.

You can buy a little two bottle cart at a welding shop, put two M
cylinders of medical or welding grade.. your choice.. put a little
manifold and filling pigtail.. and stand it in the corner of your
garage, and chain it upright for safety. You will have at least as safe
transfilling as was acceptable in the medical industry for YEARS until
recently.