Burst Disk Questions...

[dogwatch]

semi - hijack

Does anyone know what psi burst disk is supplied with a sea elite 300 bar manifold? no way to tell without disassembling.


thanks

[JS1scuba]

semi - hijack

Does anyone know what psi burst disk is supplied with a sea elite 300 bar manifold? no way to tell without disassembling.


thanks

The Sea Elite manifold is the stock manifold that comes out of Taiwan. They usually have safetys for standard aluminum 3000 psi cylinders, which would put it at a 5,000 psi rated safety. However, i had a client with a 300 Bar Dive Rite that had safetys for 2400 psi cylinders (4,000 psi rating). Those manifolds do not use the single piece captured assembly like the Thermo does, but the Thermo assembly fits the late models of both the above.

If you gently take out the assembly cap you should be able to read what is on the disc and then put the cap back on (120 inch pounds) --

cheers
jds

[Sludge]

This whole thread puzzles me. Why would anybody with a brain in their head disable the burst disk assembly? One reason would be that burst disk assemblies blow for no reason. But that's not the case. I have firsthand knowledge of FOUR times that burst disks blew.

1. A friend had a 2250 cylinder that was filled to 3000psi and left in a hot car.

2. A friend had 2400psi WP disks in a manifold and filled the doubles to 4000psi several times.

3. A co-worker walked away from the fill station while it was on "direct fill" on an AL80 and went to 4500psi.

4. Assuming the tank in his hand was rated at 3000psi, a moron at the shop filled a 2015 AL19 with a twenty-year-old burst disk assembly to 3200psi. (I won't say who this moron was, but he has an umlaut in his name.)

Twenty-four years of diving, fifteen of them working in at least one shop, and these four examples are the only time I experienced a disk going. EVERY single time, the disk *should have* blown. I don't see the problem.

Just put 3500psi WP disks in all your steel tanks and go with it.

[DA Aquamaster]

If you gently take out the assembly cap you should be able to read what is on the disc and then put the cap back on (120 inch pounds) --

No offense, but I think that is bad advice. The nylon washer is intended to crush fairly rapidly and seal (i.e. apply the torque quickly) and then the assembly is not designed to be messed with.

90% of the time you are correct and the plug could probably be removed without distrubing the disc or the washer. But the other 10% of the time you risk a leak and, particularly if you snug it up again to stop the leak, you run the risk of a premature failure at some unknown point in the future.

Burst disc assemblies are just not that expensive in the big picture when you consider what you spend on what goes in the tank and certainly not in light of the risk you take if it fails in an overhead environment due to being needlessly distrubed after the initial installation.

So in my opinion, if any portion of the assembly gets removed, it needs to be replaced. Period.

If you are in doubt of what assembly is in there, replace it. Period.

Also, for general information purposes to general forum readers, some burst disc assemblies have the service pressure on the outside of the plug, so checking the service presure they are intended for is not hard and does not require removing anything.

[JS1scuba]

No offense,,,,,

Also, for general information purposes to general forum readers, some burst disc assemblies have the service pressure on the outside of the plug, so checking the service presure they are intended for is not hard and does not require removing anything.

None taken.

adding to your comments ....

Thermo, Sanosub (OMS, Blue Steel), Sherwood and Genesis late model valves have the safety assembly stamped or marked with the burst pressure on them. (I recall this being a CGA req)

cheers
jds

[temrich]

Ok, I think I know the answer to this question, but figured I would ask here first. I bought a new set of doubles and put them together. Went to change out the burst disks only to find one 5250 disk. After putting the original plugs back in and filling, I have a very, very small leak out of one of the plugs. Question is, should I replace the plug and tighten back down or crank the *&(* out of the plug to get it to seal? Are there torque specs on thermo disks? Does EE still have the no blows? Thanks all and safe diving. Travis

[DA Aquamaster]

Generally speaking, you should not reinstall a burst disk assembly once you remove it. That is especially true in overhead diving. Nothing will dump a tank's contents faster than a failed burst disc so you do not want to screw around or get cheap by re-using one.

There are torque specs for burst discs but it depends on the whether you are using a unitized assembly or separate plug, disc and plastic washer. On the latter, the recommended torque is sometimes a bit light and a bit more is often needed to get them to seal properly. Also with the latter, you want to apply the torque fairly rapidly to prevent the plastic wahser from deforming and extruding.

Rennaker's had a bunch of the SS discs in stock in January. If you go that route be aware you need a burst disc plug intended for use with the separate burt disc and you will also need a new plastic washer (Rennaker's also had those in stock).

[temrich]

Kinda what I was thinking. Do you recall if he had the plugs that require the plastic washer? My units are all one piece. Thanks, Travis

[Sludge]

Okay, it's been eight months. Will somebody PLEASE respond to my Post #43 and give me a reason you feel I'm wrong? I would like to hear someone's opinion as to why burst disks are a bad thing.

[Line Squirrel]

Nothing will dump a tank's contents faster than a failed burst disc

Other than a failed cylinder wall....which is the whole purpose of using burst disks