Thu Aug 27, 2009 10:41 am
If the regulator wasn't on the tank then it was the rupture disk (on the opposite side of the tank thread-in under the cap with the little holes drilled in it). When these go it is quite spectacular and your wife was thoroughly justified in being frightened or at least startled. Did she describe loud noise, the bottle falling over and rolling around or it becoming sheathed in ice? These are things that usually happen when a rupture disk goes and it only takes a few seconds to empty the tank.
The only things that will cause them to blow are heating way above the critical temperature (the pressure gets high enough to pop it and that's exactly what it's for) or it was overfilled with cold CO2 in which case the liquid expands as it warms and the pressure shoots up as the (too small) headspace gets compressed. Again, that's what the disk is there for.
In either case the pressure in the tank went too high and I believe DOT regulations require that it be hydro tested before it can be refilled. As your supplier refilled it he should bear the cost of this.
But it's a little hard to imagine that the supplier overfilled. It takes some effort to accomplish this (yes, I know how to do it and have done it) and the supplier is usually more motivated to underfill somewhat so I suppose it is possible that the rupture disk was defective.
In any case, the disk will need to be replaced. If you supplier is a welding supply shop or general gas supplier and the bottle is theirs they should do this for you. If it is your bottle they may be reluctant to sell you the part (because of liability concerns) but will probably service it for you i.e. put in a new disk and do a new hydro test. Who pays for this may be the subject of discussion. If you can convince them they overfilled it, then you will probably be accomodated. If they won't accept that and blame the disk itself you are probably stuck.
