"Bob Engelhardt" wrote in message
...
On 3/17/2015 7:25 AM, Jim Wilkins wrote:
...
"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