Tank Cubic Foot Rating Question?

**Skymeat** · 10-24-2010, 12:54 PM

I'm wondering how a tank's cubic foot measurement is measured.

For example co2 is sold by weight, because it's liquid while under pressure it expands to a much greater volume when it's a gas a room temperature.

Is it just a matter of pressure? An Oxy tank will be at much higher pressure than a co2 tank, or propane if they both carried the same volume of gas uncompressed.

With a blend of argon/co2...What's the actual ratio of gas when it's compressed in the cylinder?

Just a matter of curiosity. I know I didn't articulate this thought all that well...Hope you guys can unravel it.

Thanks,
Skymeat

**whateg0** · 10-24-2010, 01:42 PM

Compressed gases, such as Ar or O2 are sized by the volume of gas at atmospheric pressure. Obviously, a 300CF bottle does not actually occupy 300CF of space. But when allowed to escape, the gas inside will. (Google Boyle's law for more detail.)

Regarding the Ar/CO2 mix, I'm not sure what you are asking, but a C25 mixture is 25% CO2 and 75% Ar. A C10 mixture would be 10% CO2.

Dave

**Skymeat** · 10-24-2010, 01:50 PM

Originally Posted by whateg0

Regarding the Ar/CO2 mix, I'm not sure what you are asking, but a C25 mixture is 25% CO2 and 75% Ar. A C10 mixture would be 10% CO2.

I think you answered it...So a C25 mix would have 25/75 mix at atmosphere. So if one were able to see through the calendar they'd see liquid co2 taking up less than 25% of the volume.