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South African - and proud of it!
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180 Posts
Discussion Starter · #1 ·
Hi all, just thought I'd share a story from this weekend...

Chap came in with 3 cylinders to be filled. Runs a boat and spends most of his time abroad in Europe and tells me that he has no trouble getting a fill in these cylinders.

Cylinder 1 - out of test - now off being tested.
Cylinder 2 - out of test and now obsolete - probably at the local tip by now.

That leaves Cylinder 3.

This is white-ish, rusty and generally nasty looking. Having lowered myself down, at a speed befitting my age, to the level of the cylinder, I check the stamp. Yes, it shows a valid test date of sometime in 2006 and an over-stamped marking that could have been an IDEST cylinder but was impossible to see clearly.

Now this could have just been over-stamped because the first attempt wasn't clear but...

Oh, before I forget, it also had "232 bar" written in black marker on the neck - not too far from the rust around the valve.

I was so busy trying to think of a valid reason not to fill the cylinder (I know I can just say no but customer usually want to know why and a simple "I don't want to" often causes offence), that I only slowly became aware of the valve. It was DIN, and the cylinder was 232 bar - not unusual. You don't often see 300 bar DIN valves on a 300 bar cylinder though!

The owner insisted that it was perfectly OK and had been tested with the valve and filled wherever he went. He then had a very polite rant about 300 bar being more than 232 bar and therefore the cylinder was even safer!

Anyway, having explained to him the requirements here in the UK and the effect that over-filling can have on a cylinder, he left - miffed and a bit grumpy.

Just goes to show - sometimes you know something's wrong, even if your brain hasn't figured it out yet. Probably a one-off but thought I'd share it in case it turns up anywhere else. - if it does, let me know...
 

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All hail the mighty ZOM
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26,851 Posts
I don't see what's wrong with having a 300bar DIN fitting on a 232 bar tank, providing it's not filled beyond 232 bar.
Cos a gas monkey with 50 cylinders to fill will just wham 300 bar in it.

Now a 232 valve on a 300 cyl makes more sense but what's the point it that? Put the right valve on it. If it goes for a visual with a 300 valve in it, the cylinder will fail. The bloke's obviously a tightwad so sell him a valve too.
 

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411 Posts
FWIW: I understand that it was a common recommendation of GI3 that 300BAR ports were used in preference to 232BAR as they are more sturdy. It is certainly a configuration I have seen many times in Asia with tek divers kit and even twin sets that were rented out from a shop.

"The ports would be 300 bar for more thread depth" is still on the GUE web site alongside recommendation for Aluminium 80s that have a fill pressure of 207BAR.

That is not to say that I don't understand the perspective of the dive shop worker busy filling lots of tanks.
 

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Kit Junkie
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804 Posts
I've had a very respected dive shop refuse to fit a 300 bar manifold onto to 232 bar cylinders...
 

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2,451 Posts
You don't often see 300 bar DIN valves on a 232 bar cylinder though!
Some of our club cylinders failed hydro and were re-tested as 207 to avoid scrapping. One of our club members had an elderly 300 bar cylinder re-graded as 232 after failing hydro, but I am pretty sure the valve was changed in the process. The re-graded cylinders are marked with the new pressue in big black numbers on the neck. The regrades were done prior to the specs change in 2002.
 

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Exiled in Scotland...
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6,286 Posts
I really wanted MDE modular valves on my 3ltr valveless cylinders I bought from Go dive. The only ones availiable were 300 bar. My LDS refused to fit them and hence fill them as they suggested it was possible to confuse the filling and hence put 300Bar into a 232 Bar cylinder.

In the end I managned to get a refund on the crossflow valves but I never got to install MDE valves, which was a big dissapointment.

Dave C
 

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Proud to be "small minded" in the face of credulit
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2,910 Posts
Some of our club cylinders failed hydro and were re-tested as 207 to avoid scrapping. One of our club members had an elderly 300 bar cylinder re-graded as 232 after failing hydro, but I am pretty sure the valve was changed in the process. The re-graded cylinders are marked with the new pressue in big black numbers on the neck. The regrades were done prior to the specs change in 2002.
[Please note I don't really know what I'm talking about {in the following passage, at least.}]

I'd be bothered about this. I see the hydro as a test of a tank's elasticity, so I'd have thought that once it's failed it's likely to fatigue quite quickly, even at lower pressures.

This is a rare occasion where I'm prepared to be wrong...
 

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1,707 Posts
Why the fuss over using 300bar valves on a 232bar cylinder? We use 232bar valves on 207bar cylinders without question. I don't believe there is such a thing as a 207bar valve. Obviously the difference between 232 and 300 is greater than between 207 and 232 but since, in my experience, a fill to 300bar is quite rare, why worry? I rarely got more than 250bar in the 300bar cylinders I had.

I can't see a problem as long as the cylinder in question is clearly marked with max fill pressure. All cylinders are stamped with this anyway.

Cheers/Nic
 

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Kit Junkie
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804 Posts
The attitude of the shop is that they do not want a stupid employee putting 300bar in a 232bar cylinder.

Mind you, since the test pressure of a typical steel 232 bar cylinder is in excess of 370 bar and you really do not want stupid people filling cylinders I think this attitude is wrong.
 

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One of them...
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233 Posts
When you test a cylinder to its test pressure you do it hydrostatically - the reason for this is twofold, first so that you can measure the expansion by the amount of water displaced over the filling, and second so that if it fails it doesn't take half the shop with it. I wouldn't ask anyone to fill to test pressure with air.

Unlike the M26 rubbish there is a good reason for the 7 or 5 thread set up of valves - compatability of filling and demand valve equipment is 'idiot proof'. Be it a non-diver filling bottles, a trainee, even someone who has dived for ten years but only ever encountered A-clamp, the simple solution of "it doesn't fit" gives you a degree of safety which is entirely lost if you put the wrong valve on a tank. FFS - they're £30!
 

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Kit Junkie
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804 Posts
I'm not suggesting to pressure test with gas only that a 232 bar cylinder should easily accept a 300 bar fill.

Also, in this case the number of threads is irrelevant. A 300 bar filling whip will fit into a 232 bar pillar valve.
 
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