Effect of Hot Fills on Tanks

[royalediver]

I don't think hot fills have any effect, steel tanks are hot dip gavlaized at 850f and alum tanks are paint cured at 265f. The bigger concern is crash fills.

CGA standards and safety assemblies are why most tanks state not to store above 125F. A full tank at elevated temps may blow the safety.

 

[Nic160]

I'll right, while were at it. What about this. Say you empty your tanks(you got 32% and you want Trimix) and they freeze(get icy) around the manifold.Any down side ?

 

[rjack321]

Yeah so what? Don't let that moisture inside, otherwise don't worry about it.

Personally, if I have to dump gas I leave a 50-100 psi or so in it at the very end. Then let the valve warm up a little bit and do my best to dry the inside of the valve. Then I blow off the last little bit of gas, hopefully taking any remaining condensation with it. Then fill.

 

[pescador775]

Yeah so what? Don't let that moisture inside, otherwise don't worry about it.

Personally, if I have to dump gas I leave a 50-100 psi or so in it at the very end. Then let the valve warm up a little bit and do my best to dry the inside of the valve. Then I blow off the last little bit of gas, hopefully taking any remaining condensation with it. Then fill.

That is the correct procedure. With a yoke valve, it is sufficient to hold the hand over the valve while blowing down the last 100 psi. This scatters the air back against the valve face.

 

[bubble-head]

This is a real pet peeve of mine. A LDS I sometimes have to go to does not use a tank of water during fills and I always end up cheated out of about 500 PSI. I am too nice because I always want to ask them why they don't use one.

 

[ClayJar]

Actually, according to what I've read, water baths don't help (much) and provide a great way to get the inside of your cylinders wet. Better to just fill them more slowly, or properly adjust for hot fills.

 

[Packhorse]

I had the same problem with my LDS. Then I simply asked them to top it off once it cooled down because thats what the guy down the road does and they obliged. Now I get nice 230 bar fills at 15 deg C.

 

[spectrum]

Actually, according to what I've read, water baths don't help (much) and provide a great way to get the inside of your cylinders wet. Better to just fill them more slowly, or properly adjust for hot fills.

A water bath like a 5 gallon pail sure does help in getting a better fill.

You are correct that by having water at the fill station you introduce the posibility of getting a wet fitting or whip and pushing water into the tank. This can be managed with a little TLC especially if wet fills are not being done constantly. As long as you trust the fill person it's a good assist.

Adjust for a good fill? Coming a cold top off always works if logistics allow. Many shops will not consider going a few hundred PSI over the rating to humor Charles.

I just left a pair of cylinders at the local dive shop. My intention was to get a nice slow fill and leave with cylinders that would cool well within 10% of rating, I'm fairly easy to please. Despite asking the wench to fill slowly and despite my repeatedly telling her that I am not in a rush when I come in for a fill she set it of whistling so you could hear it in the front of the shop. She has it in her head that resting 5 minutes on the whip will make it all good.

I just said I'll be back to get them another day. I'll come with my tank checker.

Some are not trainable.

Pete

 

[ClayJar]

"Wet Fills" (PSI)

 

[spectrum]

"Wet Fills" (PSI)

I have read it. Taken to extremes you can screw anything up. I doubt that it was written without counsel.

* Non chilled water does not introduce an overfill potential
*I have a greater condensation (chill) exposure with the cylinders standing in my garage tonight.
* I attribute no explosion protection to a pickle bucket
* I have been involved with enough fills, wet, dry, fast and slow to be confident in the benefit.
* Done as I mentioned I do not have a water injection concern.

I also give a jacket BC and use a snorkle, it all works for me.

Pete

PS Forgive my tude, I'm in a mood.