What's my valve?

[Tanks A Lot]

This appears to be a 300bar valve with a 3000psi burst disc, not a smart manufacturing choice and I'm surprised they sold this as is. Having this on a 207bar rated AL40 is not the best idea if a compressor operator is inattentive and fills this up to 300bar. Ideally, a valve is rated to the cylinder it's attached to, to make these mix-ups all but impossible.

Pictures can be so deceiving, but things that make me identify it as a 300bar capable valve are mainly the threads. It has 9 engaging threads, which is in line with the usually found 9 to 10 threads on 300bar capable SCUBA valves. 232bar rated valves show between 5 and 6 threads.

Left 232bar, right 300bar. I only had a butchered 232bar I use for teaching purposes lying around, so don't mind the cut out part.

Also, the back end of the valve looks like it is cut to 300bar standards. The recess depth for example looks to be more in line with the 8mm of 300bar valves than the 4mm on 232bar valves. The land for the O-ring is much thinner on 232bar valves than it is on 300bar valves. On 232bar you will find a land with a width of somewhere in the region of 3.75mm. 300bar valves don't have that land clearly defined, but it ends up wider. The picture looks like it would tick both boxes for a 300bar valve. Again, I find it difficult to identify things from pictures.

Left 232bar, right 300bar.

The absence of a dimple for the yoke is an aid in pinpointing this to a 300bar valves, but not a definitive identifying feature. Not all "DIN" 232bar valves are compatible with yokes, especially older ones sold in Europe.

The yoke not going over the valve is a good indicator for a 300bar valve. The 232bar valve shouldn't be "thicker" than 25mm from it's opening to the back. The yoke have a width of 25.5mm between the O-ring gland and the tip of yoke screw, allowing it to fit over the 232bar valve. 300bar valves don't have their thickness defined, but due to the added threads they automatically end up thicker, not allowing the yoke to fit over them. That being said, I have seen a few yokes not cut to standards, that easily fit over 300bar valves.

 

[Tracy]

Why would an AL40 ever have a 300 bar valve…?

This is the United States. We use psi for pressure and Bar as a part number.
Yes, seriously. Our 300 bar valves are just a designation of the valve style. We don't have or use them on 300 Bar tanks.
Yes, I know it doesn't make any sense.
Yes, I agree it is dumb.

It is still true.

 

[Sascha314]

Ah counting the threads is indeed the best detail you can do based on this picture.

In fact yes, 300bar and 232 bar rated DIN Valve have the same threads (G5/8"), however the 300 bar is "longer" and has a safety pressure release at the end.
In that way a 232 bar reg is too short to righten the o-ring sealing and you will immediately recognize. However a 300 bar reg will fit into a 232 bar valve, just not using all threads...

I could not tell the length by picture and the safety hole is not clearly visible to me. But as the threads are the same its number relates to its length. Good point, never thought about this.


But ... who stamps this as 3000 psi?

 

[Still Kicking]

But ... who stamps this as 3000 psi?

The sticker indicates the burst disc installed not the rating of the valve. The sticker should be changed if a differently rated burst disc is installed but it rarely is.

In this case the sticker indicates the burst disc should be 5000 psi (test pressure for a 3000 psi working pressure tank).

Clear as mud?

 

[OMyMyOHellYes]

Why would an AL40 ever have a 300 bar valve…?

Why not ? 300 BAR valves do not need to be affixed only to 300 BAR tanks.

Maybe all the other guy's regs were 300 BAR DIN and so all he stocked were the big boy valves (half of my regs are 300 BAR DIN - the other half are yokels). Maybe the Scubamarket was fresh out of pro valves the day he needed a valve? Maybe he didn't want folks bothering him to borrow tanks? Because chicks dig guys with more pronounced, um, valves? Why do some folks wear split fins? Why do some folks have body piercings in unspeakable places? Why do some folks post silly questions?

 

[pelagic_one]

The valve has nine threads.

 

[JMBL]

This is the United States. We use psi for pressure and Bar as a part number.
Yes, seriously. Our 300 bar valves are just a designation of the valve style. We don't have or use them on 300 Bar tanks.
Yes, I know it doesn't make any sense.
Yes, I agree it is dumb.

It is still true.

Learnt something new today. Thanks a ton. Quite confusing though.

 

[jborg]

Why not ? 300 BAR valves do not need to be affixed only to 300 BAR tanks.

Maybe all the other guy's regs were 300 BAR DIN and so all he stocked were the big boy valves (half of my regs are 300 BAR DIN - the other half are yokels). Maybe the Scubamarket was fresh out of pro valves the day he needed a valve? Maybe he didn't want folks bothering him to borrow tanks? Because chicks dig guys with more pronounced, um, valves? Why do some folks wear split fins? Why do some folks have body piercings in unspeakable places? Why do some folks post silly questions?

A 300 bar valve allows a 300 bar fill, mechanically, by way of accepting a 300 bar fill whip, and intuitively for the person doing the fill. Putting one on a non-300 bar pressure vessel would be a cardinal sin over here, if not actually illegal (I can’t be bothered to look for regulations). Certainly it would be a major surprise.

 

[OMyMyOHellYes]

A 200 BAR DIN fill whip cannot fit a 300 BAR valve/tank. A 300 BAR fill whip will fit a 200 BAR valve/tank.

Go figure.

Rule 1) Know what you are doing
Rule 2) Don't do stupid stuff

 

[jborg]

A 200 BAR DIN fill whip cannot fit a 300 BAR valve/tank. A 300 BAR fill whip will fit a 200 BAR valve/tank.

It is precisely the opposite. A 300 bar fill whip has a longer center ”dimple” which prevents sealing on a 200/232 bar valve.

(Regulators are the opposite, the rare 200 bar DIN regulator having too few threads to mate with a 300 bar valve.)