Filling Tanks
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Always blast some air out of your valves just before dropping them off for your fills. Otherwise, spray from the boat or water from the after dive rinse can be forced into the tank when they are filled.
Actually, most folks who fill tanks in most shops are not trained properly.
Actually, most folks who fill tanks in most shops are not trained properly.
pescador775
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A lot of hooey on this thread but Walter is right when he says to 'blast' out water from the valve. Of course, any physicist of high school stature will tell you that aluminum conducts heat faster than steel explaining why steel tanks must be filled in a water bath, and aluminum should be. Even room temp water cools a tank MUCH faster than air at the same temp. I'm not sure why this subject should even be up for debate. PSI? huh. If a tank (including aluminum) is filled in air by a 4 cfm compressor at 80 deg ambient the tank will lose 8-10% of its pressure (meaning your tank is underfilled 10%-regardless of other claims here). If you want a tank filled in air 'bath' the rate should not exceed 1 cfm. IOW, 1 2/3 hours to fill an 100 cf tank. How does that grab ya, ya'll? For those who own a compressor the air bath can be used. Simply return to the scene of the crime after an hour or more and add another 10%.
You gotta love it if you're a dive shop! They have one thread complaining about short fills and another one suggesting shops shouldn't use water. And of course they want it fast. LOL
I give up, do they want it full or don't they?
Even filling slow, water makes a big difference. Anyone who says different hasn't filled many tanks, PERIOD
There are some things about these boards that are a real asset but sometimes it's just the blind leading the blind.
Stone
Contributor
Here's my hypothesis: At 4 scfm, my Al80s exhibit no temperature change (to the touch); therefore, during the 15 minutes it takes to fill an AL80, the heat transfer to a water bath is insignificant. (This assumes the tank is pulled from water bath at end of fill).
Currently, I fill the AL80s to a almost 3300 psi, and the final pressure ends up a little over 3000 psi (these are relative pressures since my gauges are not calibrated). In round numbers, the AL80s lose 10% when cooled down.
If a water bath results in a 5% loss, I will stand corrected.
Currently, I fill the AL80s to a almost 3300 psi, and the final pressure ends up a little over 3000 psi (these are relative pressures since my gauges are not calibrated). In round numbers, the AL80s lose 10% when cooled down.
If a water bath results in a 5% loss, I will stand corrected.
How many have you filled in water?
Do you leak check a tank during a fill?
You mean the connection between the filler and the tank? Other than by feel, no. Why would I, unless the fill is going slower than it should be? After a fill? Yes. Does it hiss? No? Its not leaking much if at all. Since I wait for the tank to cool before analyzing, any leak of significance will be obvious when I put the analyzer on it (there's a gauge on there)
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