The rate of gas mixture equilibration (not equalization of the total pressure) depends on several things. Diameter of the "path" between the two tanks is very important. I know the I.D. of most high pressure hoses (for an SPG) is very small, and that's why cutting a low pressure hose is much worse than cutting a high pressure hose. I'd imagine a transfill whip has a larger I.D., but how big is it?
What surprised me from the thread on this last year was how long it takes for gases to mix in a single tank. If I recall correctly, some people reported that a tank with He added on top of nitrox took days to give a consistent analysis.
What surprised me from the thread on this last year was how long it takes for gases to mix in a single tank. If I recall correctly, some people reported that a tank with He added on top of nitrox took days to give a consistent analysis.