3 burst discs in a row!?

[Flatsfish B]

Just bought a new pair of worthington LP 95's. I went to my LDS today to get there first fill. One of the tanks broke 3 4000 psi burst discs in a row all well under 4000 psi. We put a 5300 psi burst disc in but now I don't know if i should trust it? Could this be a valve problem? They are thermo pro yoke style valves. The tank were originally hydro'd in 7/05. Any input is appreciated, after 3 bursts im afraid to touch the thing! The other tank has no problems so far...

Thanks for your help

Barry

 

[pdoege]

3 bursts im afraid to touch the thing!

Something is weakening the burst discs. It could be that the surface in the valve is not flat, or that the screw is not flat, or that the screw was not torqued properly.

I would bet on improper installation of the screw.

If the 5300 psi disc works then just leave it be. Have the tech inspect the burst disc assembly when the valve is serviced and see what the problem is then.

Peter

 

[Johnoly]

Hot fills, gotta love 'em. I've seen tanks pumped to 4000 psi and they cool to less than 2900 if you hot fill them. Hot tanks can take up to 6 hours to fully cool down.

So you either get a quick high hot fill to get you plenty of gas or leave your tanks over night and then get a top-off when you pick them up. I prefer the overnite method and I still run 5K disks in my LP121's also. By the way, are you pumping partial pressure blended nitrox in those tanks?

 

[DA Aquamaster]

I'd agree it's probably an issue with the screw. I would replace it as well as inspect the face the burst disc seats on in the valve. You really do not want the burst disc to let go during a dive.

 

[bet63]

You really do not want the burst disc to let go during a dive.

What would cause a burst dics to go during a dive? Does anyone know of this happening?

Thanks
Brian

 

[Scubakevdm]

What would cause a burst dics to go during a dive? Does anyone know of this happening?

Thanks
Brian

I don't know, but I bet it would mess up your trim. At least til the tank ran out. Then you'd be okay again. Maybe a bit heavy.

 

[Cave Diver]

I don't know, but I bet it would mess up your trim. At least til the tank ran out. Then you'd be okay again. Maybe a bit heavy.

Trim and a bit heavy would be the least of your problems...

 

[TheFoggyMask]

Hot fills, gotta love 'em. I've seen tanks pumped to 4000 psi and they cool to less than 2900 if you hot fill them. Hot tanks can take up to 6 hours to fully cool down.

So you either get a quick high hot fill to get you plenty of gas or leave your tanks over night and then get a top-off when you pick them up. I prefer the overnite method and I still run 5K disks in my LP121's also. By the way, are you pumping partial pressure blended nitrox in those tanks?

Great scene at fifthd. Guy walks in, and based on his self important attitude and atire, is obviously a new diver/clown. Mark had told him the tank fill would be done by the next day since he was working on mixing gases for other people, yet he come back a day early? Upon hearing this "news" he says, self important ***-hole like, "Tell you what. Wait until it cools down to fill it. I need a nice cold fill, got a big dive tomorrow!" It was an aluminum 80....a single tank. Anyone have "big dives" that need a "nice cold fill" on a single alu80?

 

[DA Aquamaster]

What would cause a burst dics to go during a dive? Does anyone know of this happening?

More often I have had old burst discs develop a slow leak, noticed as a small trail of bubbles during the bubble check, dive or with a tank with less than the previously filled pressure, or had them burst on filling. But I have also seen them just let go sitting on the boat.

My concern is that he had 3 new burst discs let go under conditions where none of them should have burst. Even if the last one is holding, I would not trust it until I fully understood why the other ones failed to ensure whatever was wrong is now fixed.

Until I knew that, the valve would remain highly suspect and I would not trust it in a hard or soft overhead environment.

 

[SDAnderson]

I've seen it at fill stations several times but only once in-water. Nobody was hurt, which made it a lot more fun than it otherwise would have been. It's really loud and there are lots of bubbles and a minute or two later you're out of air. Any trim problem doesn't come from the loss of gas but from your body's instinctive evacuation of more substantial material.

DA Aquamaster called it right: you don't want to dive until this problem is resolved. Most likely the screw or the seat is deformed; a screw is easy to replace, a bum seat is more problematic. Whatever the case, I would get the problem fixed before continuing, even if you plan to double-disc.

What would cause a burst dics to go during a dive? Does anyone know of this happening?

Thanks
Brian