DIN VALVE and K VALVE interchangeable on a aluminum 80?

[NAM001]

look for what is often refered to as a combo valve. it will only be a 200 bar din/yolk. The next thing you will probably want to know is that your regs are 300 bar din regs. they will work with the 200bar din valve. the difference is that ie the 200 has IE 10 threads and teh 300 has 13 theads on the fitting. the 300 reg will work on a 300 or 200 but a 200 din reg will only work on a 200 din valve. with that out f the way here is a link that should show you what one is. Google Image Result for http://www.scubatoys.com/store/accessories/DiveRite/ThermoStandard.jpg

with the insert to the right out it is a din valve. with the insert installed the valve willl acccept a yolk regulator.

hope this helps. btw thermo makes valves that are far less expensive than the ones in the link.

regards

 

[Peter69_56]

One more tidbit; I don't really believe that the poster from Australia got a tank back from hydrotest with 300 Bar of air because the tester 'forgot to take the test air out.' "Hydro" test, as the name implies, is done with water, not air, and never with the valve on the tank. Maybe they do things different down under, but I seriously doubt they test tanks by pumping 5000PSI of air through the valve.

I take your point that it was probably not tested with the valve in it (I suppose), however be assured it was a 3 litre aluminium pony and had 300BAR in it when I got it home and tested the pressure as I always do.

I don't know how the cylinder was hydro tested so my comment about it being a test fill remaining in the cylinder was an assumption, that being the case then the filler deliberately filled it to 300 BAR after the test????????? I would think therefore that would be negligent of them to do this.

---------- Post added June 30th, 2013 at 01:16 PM ----------

Understand that the valves are all probably rated to some 300 BAR but stamped to a rating for the bursting disk, but the failure point will most probably always be the cylinder.

The point I am simply trying to make is that to fit a higher pressure valve to a low pressure cylinder may cause a non thinking filler (and yes there are a number of them) to make an error and fill to 300 BAR. A smart filler would not and hopefully most are switched on, however clearly some are not smart. In my case the aluminium cylinder and valve are rated to 232 BAR and yet it was filled to 300 BAR ???

Its not one thing in general that causes and accident, usually a number of things and if just one link is not removed the accident never happens. After market, the Op can do what they chose, I just wouldn't as I would not like to be responsible for someone getting hurt, even if the LP valve was not the direct cause.

 

[OkByMe]

I take your point that it was probably not tested with the valve in it (I suppose), however be assured it was a 3 litre aluminium pony and had 300BAR in it when I got it home and tested the pressure as I always do.

I don't know how the cylinder was hydro tested so my comment about it being a test fill remaining in the cylinder was an assumption, that being the case then the filler deliberately filled it to 300 BAR after the test????????? I would think therefore that would be negligent of them to do this.

---------- Post added June 30th, 2013 at 01:16 PM ----------

Understand that the valves are all probably rated to some 300 BAR but stamped to a rating for the bursting disk, but the failure point will most probably always be the cylinder.

The point I am simply trying to make is that to fit a higher pressure valve to a low pressure cylinder may cause a non thinking filler (and yes there are a number of them) to make an error and fill to 300 BAR. A smart filler would not and hopefully most are switched on, however clearly some are not smart. In my case the aluminium cylinder and valve are rated to 232 BAR and yet it was filled to 300 BAR ???

Its not one thing in general that causes and accident, usually a number of things and if just one link is not removed the accident never happens. After market, the Op can do what they chose, I just wouldn't as I would not like to be responsible for someone getting hurt, even if the LP valve was not the direct cause.

300 BAR is 4410PSI. That is close to the hydro test pressure of an Aluminum tank. There could not possibly that much air pressure in the tank. The hydro is done will a liquid with the valve removed. The tank is then emptied and dried, then filled with 500PSI or so to keep it dry. Hydro facilities don't fill tanks with gases and don't usually have compressors that will fill above 3000PSI. No point since they don't do air fills.

There is NO point in giving any consideration to the the Valve pressure on a 3000PSI cylinder. Set the burst disk to 4500PSI. As long as it is designed for SCUBA and will fit a 3/4" NPS thread. Put the valve that your regulator will connect to into the tank neck with a new o-ring, fill it and go diving. I have 232BAR valves on my 3440PSi tanks with the appropriate disk pressure 5000PSI.

 

[Peter69_56]

The place that did that hydro does the fill as well, and also does Nx tank cleans. I checked the pony cylinder today and the working pressure for it is 214BAR (not 232), the test pressure stamped on the neck is 314 BAR. perhaps this never happens in USA but it does and has here in OZ. My local dive shop also does hydro, inspection, clean and fill. The cylinder in question was not done there but at another dive shop which does the same hydro, inspection, clean and fill. Both these filling stations are authorised hydro testers.

Now as I keep saying, the cylinder had 300 BAR in it after the test and fill, that is a fact. I do have a test gauge I use every time I have cylinders filled. I test them when I get home and it was 300 BAR on this occassion. I dropped it to 220 BAR, so when you say "There could not possibly that much air pressure in the tank", there was. Regardless of anything else anyone has written here, there WAS 300 BAR in the cylinder when I got it home. The tester/filler has the capacity to fill 300 BAR cylinders. As a matter of fact, one of the employees there made a comment to me a while ago that they were thinking of charging extra to fill to 300 BAR as it takes longer and is harder on the compressor.

So please accept that the cylinder was at 300 BAR. The only question is why was it at that higher pressure? My assumption was that they took it to that pressure to test it and then left it there? If you are saying that a quality tester does not test that way, I accept that. Therefore I am only left with "Not a quality Tester", or "Mistake in filling"?

Any other suggestions anyone?

 

[NAM001]

Peter

There is so much to comment about your situation, that i just cant. I do have a couple of questions however. Pls understand i am not familiar with AU.

Are costs for tanks such that divers use smaller tanks and over fill them to get the larger capacities?
As this appears to be an al tank are such drastic overfills common practice? I understand hot fills to 3300 bot not 300 bar cold.
In the US burst disks are required to hold 90% of test presure and no more than test presure. What is it there. because 314 bar would be the about the right burst presure for a 200 bar tank. 90% of
5/3*200?
Are other shops doing the same thing? If so i would tell them to not over fill, especially with the issues of stress cracking and al tanks. Higher tank psi's can only accelerate the problem.

I will say that it is clear that you knowledge of hydro and testing is not extensive and that it may be worth some time on your part to learn a bit more about the various processes and proceedures used on your tanks.

 

[Peter69_56]

Peter

There is so much to comment about your situation, that i just cant. I do have a couple of questions however. Pls understand i am not familiar with AU.

Are costs for tanks such that divers use smaller tanks and over fill them to get the larger capacities?
As this appears to be an al tank are such drastic overfills common practice? I understand hot fills to 3300 bot not 300 bar cold.
In the US burst disks are required to hold 90% of test presure and no more than test presure. What is it there. because 314 bar would be the about the right burst presure for a 200 bar tank. 90% of
5/3*200?
Are other shops doing the same thing? If so i would tell them to not over fill, especially with the issues of stress cracking and al tanks. Higher tank psi's can only accelerate the problem.

I will say that it is clear that you knowledge of hydro and testing is not extensive and that it may be worth some time on your part to learn a bit more about the various processes and proceedures used on your tanks.

Ok, thanks for the response, to answer your questions best I can;

Tank costs are expensive but most buy standard aluminium or steel with WP of around 240 BAR. Not many people (other than tech) buy 300 BAR cylinders. It appears to me smaller tanks (sling tanks of 3-9 litre) have a WP of about 205BAR (generally speaking), with "normal use" cylinders at 232 BAR.

My Cylinder data
WP 240, TP 360 Disc 360
WP207, TP 345 Disc unmarked
WP 214, TP 314, Disc 310 (This is the one found at 300 BAR)

I think this was an isolated incident and usually one finds the fills under filled rather than over filled. What I was trying to do was to come to an understanding as to why this would be the case, and my assumption was (incorrectly) that perhaps it was pressurised to 300 BAR and then not dumped back to 210 BAR. So back to the question at hand, does anyone have any thoughts as to how this particular cylinder was at 300 BAR other than (as I now suspect) a mistake and inadvertent overfill.

You are very correct in stating my knowledge in this area is not as good as it should be or what I would like it to be. Tried to find someone here in Oz who could provide a course for me but struggled to find anyone. If I chose to fly for 4 hrs there is one company in Qld. I found a company in Thailand Scubaengineer.com and was proposing to do some courses through them (anyone have any opinion on their courses). Seems that in OZ most don't teach it and if they do I would have to re-mortgage the house to pay for it. I am considering combining a dive/training trip to Thailand.

Was looking to do;
DITC, NITROX G/B & TECH & CYL PT2/HYDRO which I think allows to clean O2, inspect, hydro and reg repair.

If anyone has any suggestions as to good training facilities I would appreciate that.

I appreciate what others have been saying about cylinder pressure limits vs valve and I am probably just being anal in saying 232 BAR cylinder matches (5 thread?) 232 BAR valve, and 300 BAR cylinder matches the (7 thread?) 300 BAR valve. Minimising risks (in my mind). I like to DIR where I can and when I know, obviously when I don't know I will do what I do and hope its right. For all those who are sharpening up their fingers to tell me again it doesn't really matter, its ok, I do understand your point of view, I would just do it differently and that's me. Others will and do, do it differently and that's them.

 

[halocline]

My Cylinder data
WP 240, TP 360 Disc 360
WP207, TP 345 Disc unmarked
WP 214, TP 314, Disc 310 (This is the one found at 300 BAR)

So I'm guessing the first tank is a special permit HP tank, the 2nd is a standard AL tank, and the third is unknown to me. In the U.S. the HP steel tanks have a hydro test pressure 1.5 times the working pressure, and 3AA steel and AL tanks have a test pressure 5/3 of the working pressure.

I've heard that you have hydro test every year, is that true in Australia? In the U.S. it's every five years, so dive shops never do it. They send tanks to a test facility that also does fire extinguishers and welding tanks. If it was every year, it might be profitable for some dive shops to do it, I suppose.

The U.S. hydro test, and I suspect yours too, is done by taking off the valve, putting the tank in a water bath that's set up to measure expansion. Then water (from a different source) is pumped into the tank to the test pressure, and the amount of expansion under the test pressure is measured by the rise in level of the water bath. Then they release the pressure and measure to see how closely to the original volume the water bath drops to.

Now, there are two things really important about this; one is that the pressurization takes place in a sealed container in case the tank ruptures. Otherwise you's have the equivalent of a bomb in the test facilty. Two, they use water rather than air to pressurize the tank. Otherwise, imagine all that expanding air in a tank rupture. Again, the bomb.....

So unless they're really doing something different down there, it's impossible that they just 'left the test air' in your tank. They must have simply overfilled it to an extreme after the test. Nice to know we don't have an exclusive on knucklehead tank-fillers here.

 

[Peter69_56]

So I'm guessing the first tank is a special permit HP tank, the 2nd is a standard AL tank, and the third is unknown to me. In the U.S. the HP steel tanks have a hydro test pressure 1.5 times the working pressure, and 3AA steel and AL tanks have a test pressure 5/3 of the working pressure.

I've heard that you have hydro test every year, is that true in Australia? In the U.S. it's every five years, so dive shops never do it. They send tanks to a test facility that also does fire extinguishers and welding tanks. If it was every year, it might be profitable for some dive shops to do it, I suppose.

The U.S. hydro test, and I suspect yours too, is done by taking off the valve, putting the tank in a water bath that's set up to measure expansion. Then water (from a different source) is pumped into the tank to the test pressure, and the amount of expansion under the test pressure is measured by the rise in level of the water bath. Then they release the pressure and measure to see how closely to the original volume the water bath drops to.

Now, there are two things really important about this; one is that the pressurization takes place in a sealed container in case the tank ruptures. Otherwise you's have the equivalent of a bomb in the test facilty. Two, they use water rather than air to pressurize the tank. Otherwise, imagine all that expanding air in a tank rupture. Again, the bomb.....

So unless they're really doing something different down there, it's impossible that they just 'left the test air' in your tank. They must have simply overfilled it to an extreme after the test. Nice to know we don't have an exclusive on knucklehead tank-fillers here.

Generally speaking, we have HP steels 300 BAR
Standard Steels 232 BAR

Aluminium 232 BAR
Aluminium 200 BAR

In looking up the Luxfer site it would appear all their cylinders now in the main are 207 BAR with the exception of the 100' which are 228 BAR

I am not aware of any special permit etc for any cylinder here. Every cylinder must be inspected and hydro'd yearly. Anything before 1991 I think has to also be ultrasound tested at the neck (if you can find anyone to fill them afterwards). The cylinder under question is a Luxfer pony 3 litre (19')

I actually have 3 of the 240 BAR aluminium manufactured about 1994 and the lower pressure cylinder manufactured 2008. It would appear they have dropped the WP of their cylinders now, perhaps in response to the failures.

And yes unfortunately we have people who should not be performing the task of filling here.