Bad bottle, again.

[mccutter]

Originally Posted by randydupree

In Aircos case they were pumping pure (kinda pure i guess) argon,and then helium and then maybe Co2 into a cylinder.

You have me wondering now as I'm thinking about an 80 cylinder of Tri-mix that has been sitting full and unused probably 10 years now. It will be interesting to see what our resident chemist (alchemist ) has to say about this. This chat at Miller was inconclusive, IMO... LINK

[Shade Tree Welder]

So I called my buddy at my gas supplier. They run several fill/mix plants.

A few things, yes all bottles are filled with water prior to hydrotesting.
Otherwise if the cylinder fails the amount of energy stored in compressed gas
would be too great and cause extreme damage, whereas water is only very
slightly compressible and therefore very little stored energy, but enough for a
little pucker when they let go. They are tested at twice the working pressure.

Also most welding gas bottles have dip tubes in them, this is a tube pressed
in to the bottom of the valve and sends gas to the bottom of the cylinder.
This is to insure good mixing of the gases when filled as each gas in filled
from pure tanks. It is not uncommon for the tube to be missing from
cylinders. I have had a few cylinders with loose tubes in the past, they rattle
around.

Welding gases will mix well on their own and are not rolled. Only high
purity/precision gas mixes that have each and every cylinder QC'd are rolled
for mixing and that is just to speed up mixing prior to sampling. All gases
mix on there own completely and never separate (as mentioned by Oscar).

I like using the analogy, mix some salt in to water, cap the bottle and see if
the salt settles out. Gases are solutions just like tap water. Same thing with
the radon gas hoax, it is a ventilation (mixing) problem not a gas problem.

[randydupree]

Originally Posted by Shade Tree Welder

So I called my buddy at my gas supplier. They run several fill/mix plants.

A few things, yes all bottles are filled with water prior to hydrotesting.
Otherwise if the cylinder fails the amount of energy stored in compressed gas
would be too great and cause extreme damage, whereas water is only very
slightly compressible and therefore very little stored energy, but enough for a
little pucker when they let go. They are tested at twice the working pressure.

Also most welding gas bottles have dip tubes in them, this is a tube pressed
in to the bottom of the valve and sends gas to the bottom of the cylinder.
This is to insure good mixing of the gases when filled as each gas in filled
from pure tanks. It is not uncommon for the tube to be missing from
cylinders. I have had a few cylinders with loose tubes in the past, they rattle
around.

Welding gases will mix well on their own and are not rolled. Only high
purity/precision gas mixes that have each and every cylinder QC'd are rolled
for mixing and that is just to speed up mixing prior to sampling. All gases
mix on there own completely and never separate (as mentioned by Oscar).

I like using the analogy, mix some salt in to water, cap the bottle and see if
the salt settles out. Gases are solutions just like tap water. Same thing with
the radon gas hoax, it is a ventilation (mixing) problem not a gas problem.

What your saying on the hydrostat makes sense,the place i worked for paid the fill room guys so much per cylinder to test them,this was done after hours on the employees own time,so i never watched it being done.

But,they did roll cylinders to mix,but as you say it could have been some special mix or?
Like i said,i quit there in 1990

[Oscar]

Originally Posted by randydupree

wow,i guess the folks at Airco don't know what they are doing?

In your case,onyour home air compressor your compressing air,air already has been mixed by mother nature.

In Aircos case they were pumping pure (kinda pure i guess) argon,and then helium and then maybe Co2 into a cylinder.
So if they pumped in say,argon first it would settle to the bottom of the cylinder,its the heavy gas,so it settles.
Then if they pumped helium its lighter,so would sit on top of the argon (maybe)?
Hell,i never pumped a cylinder in my life,but for 10 years i got to see guys do it,and they used rollers to mix tri gas together.
How many cylinders have you pumped?

"Mother Nature" also mixes the gases in the welding tank. It's called physics, for which "mother nature" is a pseudonym for. Argon can initially settle, but it doesn't stay that way for more than a few seconds once you introduce other gases. I don't pump cylinders nor do I need to. Just because you saw some guys do it, doesn't mean that what you or they are imagining in their heads. Gaseous behavior is well known and studied at the university level in appropriate courses.

[Shade Tree Welder]

Originally Posted by Oscar

Gaseous behavior is well known and studied at the university level in appropriate courses.

PChem!!! I had 4 lovely semesters of it.

[mccutter]

Originally Posted by Shade Tree Welder

PChem!!! I had 4 lovely semesters of it.

What if you have a gas hose attached to a TIG torch (without a valve). The torch is resting in a holder at the table. The rest of the hose is on the floor then goes up to the flowmeter. There is no breeze or air circulation. Will the Argon "find its own level" and just sit in the hose and not mix with the less dense atmosphere?

[Shade Tree Welder]

Originally Posted by mccutter

There is no breeze or air circulation. Will the Argon "find its own level" and just sit in the hose and not mix with the less dense atmosphere?

Brownian motion and entropy take over. They will eventually mix in an open system. Takes time. But will happen.

[Shade Tree Welder]

Waiting on Gadgets response...

[digger doug]

Originally Posted by Shade Tree Welder

Waiting on Gadgets response...

Seems Mr Gadeteer is into "Broadcasting Only"....
https://www.whio.com/news/trending/w...O2JQT6MT2XKDM/

[Oscar]

Originally Posted by Shade Tree Welder

Brownian motion and entropy take over. They will eventually mix in an open system. Takes time. But will happen.

:like: