Shielding gas usage

admin

Is there an easy way to calculate shielding gas (75% Argon/25% CO2) usage?I need a way to convert from psig to cubic ft.
Reply:volume left in the bottle is proportional to the pressure.If the bottle had 220CuFt in it with a pressure of 2200PSI at 60 deg F, then when the presure is 1000PSI at 60 deg, there are 100CuFt left.Temp compensation is done by proportion as well. If the bottle was 2200PSI at 60 degF, and the temp is now 20 deg F, (which are 519 deg absolute and 479 deg absolute-- you add 459 in fahrenheit), you multiply the 60 deg pressure by 479/519 to get 2200*479/519=2030PSI as the 'full' pressure. If you now read 1000PSI, you have 220CuFt*1000/2030=108CuFt remaining.CO2 containing gasses will be off a little at temperatures below about 0 degF if the gas is aout 25%co2 or less, and will be off at higher temps the more CO2 there is, as the CO2 liquification pressure goes down with temperatre.