oxygen tank

[Lignan Christian]

Here is what I did last week, following the infos
from an A.I. (USA)
I when to a Diving shop (which sells all the stuff
for people who love to
dress in latex and breathe underwater) they took my
(steel) tank for
hydro testing, it will (hopefully) come back with the
new numbers
stamped on the metal. It has to be done every five
years.
Take a long breath
C.

[Bruce]

Lignan Christian wrote:
> Here is what I did last week, following the infos
> from an A.I. (USA)
> I when to a Diving shop (which sells all the stuff
> for people who love to
> dress in latex and breathe underwater) they took my
> (steel) tank for
> hydro testing, it will (hopefully) come back with the
> new numbers
> stamped on the metal. It has to be done every five
> years.
> Take a long breath
> C.
>
>
>
Better hope your experience is better than mine.

Wait for the - we can't test this 30 year old vessel until you provide us with
the original specifications (from the manufacturer)
Then we will hydro test it but we won't fill it because it has the wrong valve
(OK with a dive shop I later discover they should have the right fitting)
Then they won't sell you the fitting bec ause it is not certified for aircraft
use....

Then you eventually go to one of the service guys and buy the parts you need
direct from him and fill your newly certified cylinder that way.

Hopefully the dive guys will just do it.
--
Bruce Greeff
Std Cirrus #57
I'm no-T at the address above.

[Mark628CA]

I have had good luck with Medical and welding shops getting cylinders
tested. One facility in Albuquerque (Aidant Fire Extinguishers) did
several for us when I was helping run the Sandia Classic Hang Gliding
contest. They charged about $30 and had a 48 hour turnaround.

The only thing they mentioned was that the fiber -wrapped cylinders
('glass, Kevlar and Carbon) have a 15 year service life. Unless that
has changed, owners of these cylinders might have a problem in a few
years. Some fiber wrapped cylinders have been around nearly that long.

I don't think metal (steel or aluminum) cylinders have a life limit as
long as they continue to pass the pressure test and corrosion
inspection.

Mark628CA

[Eric Greenwell]

Bruce wrote:

> Lignan Christian wrote:
>
>> Here is what I did last week, following the infos
>> from an A.I. (USA)
>> I when to a Diving shop (which sells all the stuff
>> for people who love to dress in latex and breathe underwater) they
>> took my
>> (steel) tank for hydro testing, it will (hopefully) come back with the
>> new numbers stamped on the metal. It has to be done every five
>> years.
>> Take a long breath
>> C.
>>
>>
>>
> Better hope your experience is better than mine.
>
> Wait for the - we can't test this 30 year old vessel until you provide
> us with the original specifications (from the manufacturer)
> Then we will hydro test it but we won't fill it because it has the wrong
> valve (OK with a dive shop I later discover they should have the right
> fitting)

I didn't realize dive shops could/would refill oxygen cylinders, because
I thought they used air in the scuba tanks. Do they start out with
oxygen, and mix when they fill?


--
Change "netto" to "net" to email me directly

Eric Greenwell
Washington State
USA

www.motorglider.org

[5Z]

I got my filling hose and gauge from an online scuba supplier as the
local gas house didn't want to sell such supplies to "the public" -
whatever that means.

Divers do a lot of transfilling and gas mixing for deep diving, etc.

-Tom

[GeorgeB]

On Tue, 07 Feb 2006 10:09:06 -0800, Eric Greenwell
> wrote:

>I didn't realize dive shops could/would refill oxygen cylinders, because
>I thought they used air in the scuba tanks. Do they start out with
>oxygen, and mix when they fill?

As another poster mentioned, there is, in the high end, mixed gas
diving. In the last 10 or so years, NITROX has become more
mainstream; my understanding, but with nothing to backit up, is that a
tank is filled to several hunderd psi with O2 then topped off to the
normal pressure (usually 3000) with air. As an approximation, if we
started with 79-21 N2-O2, you might get (TOTAL SWAG) 70-30. I've not
done any scuba since recreational diving began the NITROX stuff, so
don't know what the improvements are; I'd guess if one could slow
their breathing, the benefits would be longer time.

George

[chipsoars]

5Z wrote:
> I got my filling hose and gauge from an online scuba supplier as the
> local gas house didn't want to sell such supplies to "the public" -
> whatever that means.
>
> Divers do a lot of transfilling and gas mixing for deep diving, etc.
>
> -Tom

meaning that working with compressed gas is hazardous and they don't
want the liability exposure. I've worked around compressed gases for
years and part of OSHA mandatory safety training is required on an
annual basis.

As you are probably aware, there is lot of heat generated when filling
the cylinder. Hence the need for hydrostatic testing. The cylinder
self destructs if it fails the test.

I cringe every time I see a p/up truck with regulators on cylinders on
the road, instead of properly capped. I had the opportunity to see
what happens when a large O2 welding cylinder which was unsecure in the
bed of a truck, with no cap, fall off and knock the valve off.

[Rory O'Conor]

I have been attempting to go down the diving route
for a refill.

It seems that our aviation cylinders require hydrostatic
testing every 5 years (every 2.5 years for subaqua
cylinders). I think the European standard is CE as
against US DOT.

Having tested the cylinders, they may want to 'O2 clean'
the cylinder before filling it with pure Oxygen. Because
there seems to be a worry that any stray hydrocarbons
will set off an explosion.

The diving shop said that they would replace all the
O rings on cleaning. DG dont have any o ring sets.
So I am currently wondering what to do if I reach that
stage.

The fitting is likely to be totally different and you
will need the right adapter. The DIN fitting on DG
aviation cylinders is an external DIN and totally different
from the internal DIN on diving cylinders. Diving cylinders
also use 'yoke' and medical cylinders use 'pin/index'.
RD aviation sold me an adapter (at a price).

I am not sure how easy it is to get Oxygen at 200 bar
from diving shops, because most is mixed with air as
nitox or trimix. Thus they can start with a relatively
low oxygen pressure (50-100 bar) and then top it up
to 200 bar with breathing air.

So I still have a comparatively new cylinder with 100
bar of oxygen and I shall have a few more flights before
I get this out of date cylinder hydrostatically tested
and refilled.

Rory

[Richard]

Craggy Aero is offering a 10% discount of all Mountain High Oxygen
Equipment until Feb 27, 2006. Purchase a new cylinder the price is
reasonable and very little hassel.

Richard
www.craggyaero.com

[GeorgeB]

On 8 Feb 2006 08:57:08 -0800, "chipsoars"
> wrote:

>As you are probably aware, there is lot of heat generated when filling
>the cylinder.

I don't really know how to "generate" heat by transferring a
compressed gas from one storage container to another; yes, the heat of
compression will cause the filled cylinder to get warmer (and the
supplying source to cool), but at the rates to which I am accustomed,
it doesn't get even uncomfortably warm to touch.

>Hence the need for hydrostatic testing.

Well, ok? ... Huh?

>The cylinder self destructs if it fails the test.

I've personally done only 4 hydrostatic tests of cylinders; one failed
because the recovery was too little. We filled with deionized water,
pressurized to 5/3 stamped pressure measuring water needed to do so,
then verified that we got (man, I've forgotten that number, think it
is 95%) out dropping back to atmospheric .

I've witnessed perhaps 200; none that failed was exciting. What other
method of hydrostatic testing is used?

Now the one talked about in every scuba shop in the country ...
1960's, I'd guess? ... when a guy's buddy told him he'd give him a
GREAT paint job on his cylinder at his "paint" line at work ... and
the freshly powder coated cylinder was being filled with air ... the
heat treated aluminum tank was annealed during powder coating and my
memory is that the explosion killed and injured and did lots of
property damage.

[GeorgeB]

On 8 Feb 2006 17:47:48 GMT, Rory O'Conor
> wrote:

>Having tested the cylinders, they may want to 'O2 clean'
>the cylinder before filling it with pure Oxygen. Because
>there seems to be a worry that any stray hydrocarbons
>will set off an explosion.

VERY WISE.

>The diving shop said that they would replace all the
>O rings on cleaning. DG dont have any o ring sets.
>So I am currently wondering what to do if I reach that
>stage.

I'd guess there to be either 1 or 2. It will likely be a standard
size, either AN or metric. Does DG give the sizes? I'd guess that
flourocarbon (tradename is commonly used, Viton, but duPont doesn't
like that) is better than nitrile or buna (perbunan in Germany, I
think). Your local seal house can get you some; the minimum order may
hurt, but the individual units won't be bad.

>I am not sure how easy it is to get Oxygen at 200 bar
>from diving shops, because most is mixed with air as
>nitox or trimix. Thus they can start with a relatively
>low oxygen pressure (50-100 bar) and then top it up
>to 200 bar with breathing air.

In the US, "standard" cylinders are about 150 bar fresh from the
supplier; I don't know what other pressures are used. I work with
Nitrogen cylinders at 415 bar.