200 bar versus 300 bar manifolds and valves

[techintime]

For my education can someone clarify whether it is acceptable to use a 200 bar manifold or valve on HP steel tanks? As I do the math, 200 bar x 14.7 psi = 2940 psi. Therefore this sounds like it is going to be exceeded by the 3500psi fill on HP steel tanks. While I imagine that the manifold/valve is tough enough to handle the extra pressure, what about the burst disk? Is the burst disk on a 200 bar manifold/valve set to burst at a pressure lower than 3500 psi?

 

[ae3753]

For your reading pleasure:
200 vs 300 bar manifold

 

[200 Bar]

Another good source on this subject is in the library of divegearexpress...(I have no affiliation)

I found this for ya a good read....

http://www.divegearexpress.com/library/valves.shtml

 

[techintime]

Good info...In a practical sense it looks like the compatibility issue comes down to burst disks. Can someone enlighten me on the options here? What burst disk for AL versus LP versus HP tanks?

PS: I appreciate the good info and polite responses compared to another thread I started where some over-cooked egos took offense at my asking of a common question.

 

[netmage]

For my education can someone clarify whether it is acceptable to use a 200 bar manifold or valve on HP steel tanks? As I do the math, 200 bar x 14.7 psi = 2940 psi. Therefore this sounds like it is going to be exceeded by the 3500psi fill on HP steel tanks. While I imagine that the manifold/valve is tough enough to handle the extra pressure, what about the burst disk? Is the burst disk on a 200 bar manifold/valve set to burst at a pressure lower than 3500 psi?

Not sure to what extent this is covered in the library docs on the DRE website...
But you really need to differentiate nomenclature.... and yes - to anyone nitpicking - I'm generalizing....

HP typically refers to older high pressure steel tanks rated to 3500psi. These tanks will have a 300 bar din valve outfitted and have a 7/8ths neck threads.

LP typically refers to low pressure steel tanks, rated to 2400/2640psi w/ the 10% overfill. These tanks will have the 200 or 232 convertable valve, and have a 3/4ths neck.

Along came PST (and followed by worthington, faber, etc....) and they decided to introduce tanks rated to 3442, or 232bar, which was seen as the limit of the yoke type reg attachment. This allowed them to market a single tank/valve combination to both the DIN and YOKE (w/ doughnut\adapter) crowds with the more common 3/4ths neck......

Ok - got all that....? Now we move onto burst discs....
You should get burst discs appropriate for the pressures your tanks will be seeing. I've seen some unscrupulous shops swap out discs if they saw you had the 'wrong'/higher pressure than rated, if you went in for a fill.

In some parts of the country, it is not uncommon to have people solely use 5500psi rated discs in all of their steel tanks irregardless of the actual tank pressure rating.

-Tim

 

[NAM001]

For my education can someone clarify whether it is acceptable to use a 200 bar manifold or valve on HP steel tanks? As I do the math, 200 bar x 14.7 psi = 2940 psi. Therefore this sounds like it is going to be exceeded by the 3500psi fill on HP steel tanks. While I imagine that the manifold/valve is tough enough to handle the extra pressure, what about the burst disk? Is the burst disk on a 200 bar manifold/valve set to burst at a pressure lower than 3500 psi?

i think that burst disc's must hold 90% of test presure before blowing . that said that may only be true for tank valve and not manifolds. your 3500 tanks would test at 5/3 op presuire or 5600 and burst at 5000 or better.

i would thinnk that you would have burst disc's installed to match the tanks fitted to.

i would think that the 200 bar manifold would have 90% of 5/3 of 200 bar disks in them as 3000# tanks are common.

perhaps someone else has better info?????


my faber lp 95's test at 4000 and burst at 3600 or better.

 

[NAM001]

Good info...In a practical sense it looks like the compatibility issue comes down to burst disks. Can someone enlighten me on the options here? What burst disk for AL versus LP versus HP tanks?

PS: I appreciate the good info and polite responses compared to another thread I started where some over-cooked egos took offense at my asking of a common question.

in addition to the other post to you here is some more info to digest. if you have had your tanks hydro's and you had valves in them i believe it is the hydro shops responsibility to verify the correct burst disk is installed. my valves are removed befor sending out for hydro. the shopo keeps my valves. ther3e is also something about filling tanks that says check hydro date do a quivk visual external inspection for damage and check the valve is corredct for the tank being filled. most valves have a sticker on it stating the working presure of the valve's burst disk. ie mine say 2400 on the valve which means 3600# burst. the actual burst presure can not be verified without disk removal from valve. many put as said in another post a 5500# burst disk in a 2400 # valve. the filler must assume the 2400# marking is correct and a 3600 disk is installed.

 

[Gombessa]

many put as said in another post a 5500# burst disk in a 2400 # valve. the filler must assume the 2400# marking is correct and a 3600 disk is installed.

All my LP tanks have HP burst discs in them. On my valves that actually have service pressure stickers, they've also been replaced with ones corresponding to the burst discs installed. On most (not all), the burst disk itself has the burst pressure stamped onto it.

 

[DA Aquamaster]

Burst discs are designed to fail at 90% to 100% of the test pressure. THe test pressure on 3AA and 3Al tanks is 5/3rds the service pressure while on most exempt/special permit tanks it is 3/2 the service pressure.

So...for a 2400 psi tank the normal burts disk pressure would be 3600-4000 psi. For a 3000 psi tank it would be 4500-5000 psi and for a 3442 psi special permit tank it would be 5163-5736psi. The burst disc in a 3500 psi tank would be 5250-5833 psi. The last two are in effect the same for all practical purposes.

With 2400 psi tanks that you are overfilling to 3600 psi, the normal burst disc used in a 2400 psi tank is not going to be adequate as you are essentially filling the tank to 90% of the test pressure. A 3000 psi burst disc is adequate, at least until the disc wears/corrodes a bit, so the best approach is to use a burst disc intended for either 3500 psi service pressures, or use one intended for 4350 psi service pressures.

In terms of 200 versus 300 bar valves, the strenght of the valve was NEVER the consideration as the extra 2 threads in the 300 bar valve are not needed for strenght. What they add is additional lenght that was intended to prevent a regulator rated at aonly 200 bar from being attached to a tank with 300 bar pressure. Now however, there are basically no 200 bar regs and they all come with the longer 300 bar DIN connection anyway, so it is a safety measure that is now obsolete.

 

[NAM001]

In terms of 200 versus 300 bar valves, the strenght of the valve was NEVER the consideration as the extra 2 threads in the 300 bar valve are not needed for strenght. What they add is additional lenght that was intended to prevent a regulator rated at aonly 200 bar from being attached to a tank with 300 bar pressure. Now however, there are basically no 200 bar regs and they all come with the longer 300 bar DIN connection anyway, so it is a safety measure that is now obsolete.

thanks great info to know.