claymore
Contributor
Hey guys the toilet is getting full can we flush this pissing match down the drain.
Tanks - True cost of ownership
- Thread starter jzipfel
- Start date
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I'm in no contest! 
gcarter
Contributor
Sounds like a recipe for moisture in the tank to me.
Moisture from where?
A little phenomenon called condensation.
R
redacted
Guest
Doing some rough calculations it would seem that the freeze with an open valve followed by closing the valve and allowing it to return to ambient would only get you an extra psi or 2. And, on a worst case basis that gas would have a relative humidity of about 25% at room temperature so the moisture content would be about what you would expect from opening a tank up to do a visual inspection. No big deal.
Or you could freeze the tank with the valve closed and open and close it when you remove it from the freezer to get almost the same pressure increase with much less moisture.
But that sure seems like a lot of trouble to gain less than a couple psi that may not even be audible.
This reminded me of one of those “tricks” I have seen that could be considered a little over the top by some. Before the first fill after installing a valve, pressurize the cylinder to 50 PSI and bleed it off to near zero a few times. The theory is that 30-50 PSI isn’t enough to cause much condensation due to compression and purging a few cycles with very dry air “should” reduce the amount of moisture trapped in the cylinder.
I have never seen it actually tested and it probably wouldn’t matter very much if the first fill is used soon after filling. Every fill cycle dilutes any ambient moisture trapped in the cylinder when the valve is screwed on. I guess you could get really anal and drop a hose in the cylinder to blow dry air in before installing the valve as well.
Why even mention it? Maybe it might help people who have not thought about it very much to visualize the role of moisture in cylinders.
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