Air Venturi 5000psi Burst disk lived up to its name. What a rocket!

[Yarp]

I had a "fetch me my brown pants" moment thirty minutes after having a 90 cu in Carbon fiber tank filled to 4400 psi.

The 5000 psi burst disk let go and the tank shot across the room, smacked into the wall, and hit the floor spinning. Thanks to some neoprene there was no damage to the wall or tank, but I'm having second thoughts about paintball gear that has been adapted for airgun use.

 
 

[Rescue912]

Glad you are ok, definitely scare the hot water out of you though ...

[Yarp]

It was just a burst disk, not a tank blowing....But still more excitement than wanted outside of a trip to Busch Gardens.

[clgraham82]

WOW!  Glad you're ok!

[Yarp]

Thanks, but it was nothing other than unexpected excitement.

The 4500 psi tank came protected with a 5000 psi burst disk, and that is way close for comfort. I'm left wondering why rupture pressures other than 1800, 5000 and 7500 psi haven't been developed and marketed. 

[Yarp]

10%?  That puts the 5K disk right on top of the tank's working pressure.
It has just been replaced with one rated at 7K.
 
The blow was fairly dramatic. My little bottle shot from a tabletop and whammed into a wall a four or five feet away.
Its burst disk continued to vent (and ice up) a minute or two after it was retrieved and set on back on the table.

I don't want to be around when the disk on a big tank goes. A big tank might not move around much, but the thought of all of that potential energy going kinetic is a fright.

[rsterne]

A tank rated at 4500 psi MSWP should be hydrotested to 7500 psi and then fitted with a 7.5K burst disc on the input side of the regulator.... The one on the output side should be not higher than 5K.... Proper burst discs have a relatively small hole in them to prevent what you experienced, I have had several go on a 3000 psi setup and the tank didn't even move.... I'm guessing that somebody installed the wrong disc, both for rating and diameter of the vent hole....

Bob

[Sfttailrdr46]

  Slightly off topic but sort of the same dropped a 2 litre diet coke  bottle from about 3 ft it hit the floor and traveled 50 or 60 feet across the floor and that is a lot less pressure. Lucky you were not hurt or hit by that bottle rocket

[Yarp]

A tank rated at 4500 psi MSWP should be hydrotested to 7500 psi and then fitted with a 7.5K burst disc on the input side of the regulator.... The one on the output side should be not higher than 5K.... Proper burst discs have a relatively small hole in them to prevent what you experienced, I have had several go on a 3000 psi setup and the tank didn't even move.... I'm guessing that somebody installed the wrong disc, both for rating and diameter of the vent hole....

Bob

Bob,

This isn't the first problem I've had with the rig. After the first fill, the yoke (from the same supplier) leaked. It worked out to be a bad valve, and after making the replacement another problem surfaced on the third fill. If this is the result of shoddy work on the bench, what else might go South? Should I be looking for a different valve and/or fill yoke?

Thanks,

David

[Yarp]

Slightly off topic but sort of the same dropped a 2 litre diet coke  bottle from about 3 ft it hit the floor and traveled 50 or 60 feet across the floor and that is a lot less pressure. Lucky you were not hurt or hit by that bottle rocket

Fortunately the excitement was caused by a short burst disk. All of that high pressure air was escaping through a very tiny orifice. Still, the potential for disaster makes one appreciate the value of regular hydro testing.

[mista meener]

Slightly off topic but sort of the same dropped a 2 litre diet coke  bottle from about 3 ft it hit the floor and traveled 50 or 60 feet across the floor and that is a lot less pressure. Lucky you were not hurt or hit by that bottle rocket

Fortunately the excitement was caused by a short burst disk. All of that high pressure air was escaping through a very tiny orifice. Still, the potential for disaster makes one appreciate the value of regular hydro testing.

There is no way around hydro testing but one would think cranking the tank up to 7500 psi every 3 years would weaken it after a few tests

[SciGuy]

Isn't hydro every 5 years?

[mista meener]

Isn't hydro every 5 years?

whenever it is. it should be studied if pumping a tank up to 7500 psi stretches the metal therefore weakening it

[rsterne]

Yes, they measure the tank before and when filled to find out if it has expanded past a certain limit, and then again afterwards to insure it has returned to its original size.... As long as it passes the measurements tests it is recertified, except for Carbon tanks which have a 15 year limit....

Bob

[mista meener]

Yes, they measure the tank before and when filled to find out if it has expanded past a certain limit, and then again afterwards to insure it has returned to its original size.... As long as it passes the measurements tests it is recertified, except for Carbon tanks which have a 15 year limit....

Bob

Bob do you think with the metal going back and forth like that would weaken it?

[Yarp]

Isn't hydro every 5 years?

Carbon composite SCBA tanks are on a five year plan, but my fiberglass reinforced Luxfer (4350 psi) tank requires hydro testing every three years.

[rsterne]

Yes, and to a greater degree than what happens every time we fill and drain a tank.... However, that is taken into account, and the measurements are such that if a tank passes Hydro and then isn't filled past its MSWP and given reasonable care (ie not abused) it should be fine until the next Hydro.... That's the whole point.... I believe the 15 yr. service life on the CF tanks is because they are unsure of the Epoxy resin degrading after that, particularly in the environment they are intended for (firefighting)....

Bob

[RobAGD]

Sorry to hear about your unexpected excitement.

I assume that you are running a Ninja PCP 90ci 3k out set up ? Not sure how yours became a rocket, at worst it may roll a bit or spin a bit like a top, but not fly, unless the body of the burst disc failed.

We have been using Ninja Regulators for years with minimal issues, but every now and then you get a little junk on the HP seal on the regulator piston.

Ninja make a service kit and given I would expect your system isn't that old I would call and talk to a tech, they will get you straight in fairly short order.

If you have a local paintball shop that sells Ninja tanks they should also have the service parts.

Don't give up on  it yet

-Robert

[Yarp]

Not should how yours became a rocket, at worst it may roll a bit or spin a bit like a top, but not fly, unless the body of the burst disc failed.
-Robert

Replacing the under spec burst disc was a no-brainer. The bottle, regulator and fill hardware are working fine, and the only lasting damage is the gashed out chunk of neoprene cover from the impact of my bottle hitting the wall. BTW, thanks for putting my mind at ease. I'm relieved to find out that this could not have happened!

[RobAGD]

It is not out of spec, that is the low side safety. It should be 5k and if it popped I would personally replace the piston, just as a CYA thing, if its not regulation that can create other issues for your fill system.

I have been dealing with HP air for 20 years, and I have had many tank high side discs fail, and I have never had a newer style unified disc cause a tank to "fly" or "missile".  The old style center vent and 1 orifice vent would cause would cause a tank to dance a bit or skitter around. Just my experience with high pressure air and these types of systems.


-R