"Bob Engelhardt" wrote in message
...
On 3/17/2015 12:47 PM, Jim Wilkins wrote:
"Bob Engelhardt" wrote in message
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On 3/17/2015 7:25 AM, Jim Wilkins wrote:
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"Tanks are normally filled and sold by volume not pressure."
PV = nRT
...

I wonder how they measure volume, if not by pressure! Especially
since cylinders are often/usually filled from a manifold & many
cylinders in parallel. Unless there is a flow gauge on each tank.
Doesn't sound right to me.

Bob

Cylinder gas is sold by the volume when expanded at atmospheric
pressure.
http://www.alspecialtygases.com/volu..._cylinder.aspx

You can calculate the amount you actually received if you know the
pressure, temperature and 'water' volume of the cylinder, or like
packaged food you can just trust them.

-jsw


Right, I know. That's why I wondered when your quote from the
practicalmachinist said: "Tanks are normally filled and sold by
volume not pressure." I'll repeat: how do they measure it if NOT by
pressure?

Bob

I put the Ideal Gas Law equation, without comment, under that quote to
see if anyone caught on that I disagree with it.

Yeah, it was Sheldon/Amy humor.

-jsw