Quote: (Originally Posted by
jradomski)
It depends on the cylinder size.. filling 17l twins at 200 psi per minute is alot of flow, filling a single 2l tank at 200psi per minute is not that much (less than 30 lpm )..
I might be wrong, so please correct. Its been awhile since my fill training. This is interesting as I continue to struggle acquiring cleaning solvents for tanks/valves that are due.
I gather risks associated with flow-rate are associated with rapid deceleration of molecules within the whip (discontinuities). Hence reason to keep to a safe rate, which implies very low at start when destination pressure is very low, and higher as destination P gets higher. An issue more relevent with filling of larger bottles.
With smaller bottles, adiabatic heating happens so much easier. Given the small volume, practical to just keep a very low rate all the time. If I feel the bottle getting warm, then I make the assumption that it's too much, and I needle it down some more. I'm normally in the 6-7 bar/min camp, but my bottles are more dangerous.