DIN VALVE and K VALVE interchangeable on a aluminum 80?

[Griffo]

Converter is the cheaper option, valve change is the better option but higher cost. I know in OZ they are considering charging more for 300BAR fills as it takes longer and is harder on the compressor and eats up compressor run time thus more expense to them. Often we struggle to get fills above 200 BAR (I like 230 BAR as the norm)

St

Really? There's not a dive shop in Vic that would get away with giving you less than 230 bar. Normally you'll get 250 or so if you know them, and they will all give you 250 hot for a 230 cold fill. It is harder to get a 300bar fill though which is why I didn't bother with 300bar tanks.

 

[Tortuga68]

There's not a dive shop in Vic that would get away with giving you less than 230 bar

I guess you've never had a fill from Dive Vic in Portsea

 

[Griffo]

Not heaps to be honest. I normally take full tanks when I go onto the Div-Vic boat, but the few times I have had fills from them I've never noticed a short-fill.

 

[Peter69_56]

Well obviously you have great dive shops. There are a number of dive shops that give anywhere between 180 BAR to 250 BAR depending on the filler, Dive Vic being one of them.

Another dive shop close to me can be very variable and this depends again on who does the fill. I fill my own cylinders from their compressor and ensure that I get 250 hot. I guess if you have a number of dive shops close by the competition makes them perform better in this regard. The nearest to my dive shop is about 70 km away from them. Perhaps a captive market.

I do however agree that most dive shops in Victoria would not want to fill 300BAR cylinders. I think Scuba Doctor is one that will. I think many of the other shops have compressors too old and not up to scratch, or just don't wish to spend the time to fill them.

 

[OkByMe]

If I am reading this right, you are wanting to put a 300 BAR DIN valve into a 232 BAR aluminium cylinder. My thoughts are its not a smart move as someone along the line may fill the cylinder to 300 BAR. If you want just DIN, why not fit a 232 BAR DIN, which will take a 300 BAR DIN regulator but will align with the cylinder being 232 BAR. I know you can screw a 300 BAR line into it or a 232 BAR line and pump it to 300 BAR. I guess it goes against my grain to do it and potentially cause hurt to someone because they make a mistake based on what one has done.

Perhaps the words I am looking for are technically wrong and ethically wrong, but very doable and probably not illegal.

All my DIN regs are 300 BAR so I can fit them to 300, 232 DIN or 232 YOKE with insert. All my cylinders are 232 BAR with appropriate 232 BAR DIN valves

The valve has nothing to do with the fill pressure for the tank, that is stamped on the tank shoulder and that is the limiting factor. There is no reason to use a 300 bar valve unless it is a 4500psi tank. Even though the regulator says 300BAR, it is unlikely the first stage seats will last long under that pressure. The valve installed on the tank needs to have the burst disk pressure rated about 20% over the tank pressure. That way the disk will open if the tank is in a fire, but not if in your trunk on the back of your truck with the sun on it. Since the Hrydro testing is usually done at 5/3 the operating pressure of the tank, it will protect the tank from ruptures. Tank valves must meet the same contraints as the tank, which is at least 5/3 operting pressure. So a 232BAR valve should operate fine at3400psi and not rupture to 5000psi or so. Since the burst disk will open at about 3600psi, both the tank and valve will never see the max pressures. That 300 or 348BAR started in Europe and they usually don't have overpressure devices on their valves.

I have a couple of Faber 232BAR (348BAR test) tanks with 232BAR DIN/Yoke valves with M25x2 threads and no overpressure device and I fill them to 3500psi. @100deg.

 

[Peter69_56]

[QUOTE=OkByMe;6774937]

If I am reading this right, you are wanting to put a 300 BAR DIN valve into a 232 BAR aluminium cylinder. My thoughts are its not a smart move as someone along the line may fill the cylinder to 300 BAR. If you want just DIN, why not fit a 232 BAR DIN, which will take a 300 BAR DIN regulator but will align with the cylinder being 232 BAR. I know you can screw a 300 BAR line into it or a 232 BAR line and pump it to 300 BAR. I guess it goes against my grain to do it and potentially cause hurt to someone because they make a mistake based on what one has done.

Perhaps the words I am looking for are technically wrong and ethically wrong, but very doable and probably not illegal.

All my DIN regs are 300 BAR so I can fit them to 300, 232 DIN or 232 YOKE with insert. All my cylinders are 232 BAR with appropriate 232 BAR DIN valves

The valve has nothing to do with the fill pressure for the tank, that is stamped on the tank shoulder and that is the limiting factor. There is no reason to use a 300 bar valve unless it is a 4500psi tank. Even though the regulator says 300BAR, it is unlikely the first stage seats will last long under that pressure. The valve installed on the tank needs to have the burst disk pressure rated about 20% over the tank pressure. That way the disk will open if the tank is in a fire, but not if in your trunk on the back of your truck with the sun on it. Since the Hrydro testing is usually done at 5/3 the operating pressure of the tank, it will protect the tank from ruptures. Tank valves must meet the same contraints as the tank, which is at least 5/3 operting pressure. So a 232BAR valve should operate fine at3400psi and not rupture to 5000psi or so. Since the burst disk will open at about 3600psi, both the tank and valve will never see the max pressures. That 300 or 348BAR started in Europe and they usually don't have overpressure devices on their valves.

I have a couple of Faber 232BAR (348BAR test) tanks with 232BAR DIN/Yoke valves with M25x2 threads and no overpressure device and I fill them to 3500psi. @100deg.

I agree with you in all but the following; "The valve has nothing to do with the fill pressure for the tank, that is stamped on the tank shoulder and that is the limiting factor"
The limiting factor is the lowest attached item in the chain ie, if the reg is 235 BAR then that's the limit, if its the valve then that's the limit, if its the cylinder then that's the limit, but I take your point, any switched on tank filler will look at the cylinder rating if asked to fill above normal pressures. My real issue is that I know of some really dumb tank fillers (usually low paid shop assistants who don't dive much, are very young and really don't understand what they are doing or the risks involved.


I also don't know that I agree with "Even though the regulator says 300BAR, it is unlikely the first stage seats will last long under that pressure",
I agree that their service life will be reduced below that if used at 300BAR instead of 235 BAR but they will provide reasonable service. I have had no issues to date and neither has anyone here who use the higher pressures.

 

[OkByMe]

[QUOTE=OkByMe;6774937]


I agree with you in all but the following; "The valve has nothing to do with the fill pressure for the tank, that is stamped on the tank shoulder and that is the limiting factor"
The limiting factor is the lowest attached item in the chain ie, if the reg is 235 BAR then that's the limit, if its the valve then that's the limit, if its the cylinder then that's the limit, but I take your point, any switched on tank filler will look at the cylinder rating if asked to fill above normal pressures. My real issue is that I know of some really dumb tank fillers (usually low paid shop assistants who don't dive much, are very young and really don't understand what they are doing or the risks involved.


I also don't know that I agree with "Even though the regulator says 300BAR, it is unlikely the first stage seats will last long under that pressure",
I agree that their service life will be reduced below that if used at 300BAR instead of 235 BAR but they will provide reasonable service. I have had no issues to date and neither has anyone here who use the higher pressures.

There is only one SCUBA tank under special permit that can handle 300BAR -4410PSI. The OP is wanting to use an aluminum tank @3000PSI. Even if he had a HP steel, a 232BAR valve is good enough. I can assure you that the only device in the chain that is used to determine the fill pressure is specifically stated as the Cylinder working pressure, not the valve. As in any case were malfeasance is possible.... there is no cure for stupid. I can't imagine somebody assigned to fill tanks would try to top a tank with a Sherwood 6000 valve to 6000PSI, even if the compressor or bank output was boosted. I buy and refurbish steel tanks for my own use and have never put a 300BAR valve on any of them.

 

[Peter69_56]

There is only one SCUBA tank under special permit that can handle 300BAR -4410PSI. The OP is wanting to use an aluminum tank @3000PSI. Even if he had a HP steel, a 232BAR valve is good enough. I can assure you that the only device in the chain that is used to determine the fill pressure is specifically stated as the Cylinder working pressure, not the valve. As in any case were malfeasance is possible.... there is no cure for stupid. I can't imagine somebody assigned to fill tanks would try to top a tank with a Sherwood 6000 valve to 6000PSI, even if the compressor or bank output was boosted. I buy and refurbish steel tanks for my own use and have never put a 300BAR valve on any of them.

Understand what you are saying. I agree there is no cure for stupidity unfortunately. I understand your comments about the tank being the norm for setting max fill pressure and agree, but keep thinking of the stupidity clause. I agree most fill stations don't want to know you if you ask for 300 BAR, they struggle to give 235 BAR.

If you want 300 BAR get FABER tanks at 300 BAR, otherwise just be like everyone else and use 235 BAR. If you want more air take more cylinders.

There are some wankers out there though. I can relate a story from a test station, a cylinder failed and he drilled a hole in it to fail it, some months later he got this cylinder to test, it had a tape on it. Funny he said, so lifted the tape and found a screw put into the same cylinder he had previously failed and drilled. Some people are just brain dead. Had the screw put in it to fill the hole he put in, had it let go it would have been like a bullet. Now the company uses a chisel on the O ring seat and thread.

 

[OkByMe]

Understand what you are saying. I agree there is no cure for stupidity unfortunately. I understand your comments about the tank being the norm for setting max fill pressure and agree, but keep thinking of the stupidity clause. I agree most fill stations don't want to know you if you ask for 300 BAR, they struggle to give 235 BAR.

If you want 300 BAR get FABER tanks at 300 BAR, otherwise just be like everyone else and use 235 BAR. If you want more air take more cylinders.

There are some wankers out there though. I can relate a story from a test station, a cylinder failed and he drilled a hole in it to fail it, some months later he got this cylinder to test, it had a tape on it. Funny he said, so lifted the tape and found a screw put into the same cylinder he had previously failed and drilled. Some people are just brain dead. Had the screw put in it to fill the hole he put in, had it let go it would have been like a bullet. Now the company uses a chisel on the O ring seat and thread.

There is no steel SCUBA cylinder available out there, that is not wrapped, that is designed to hold more than 3500psi. Faber specifically says on the shoulder - "do not overfill". I don't know what kind of regulations governing Cylinder permitting you have there, but here it is the department of transportation. This agency specifically defines the fill pressure of a cylinder to be the determining factor. The valve is selected by the operating pressure of the cylinder and the burst disk is sized for that pressure.

 

[halocline]

Even though the regulator says 300BAR, it is unlikely the first stage seats will last long under that pressure.

I liked most of what you said in your post except for this. It's a bit of a fallacy that higher tank pressure wears out HP seats. The pressure forcing the seat against the orifice or piston edge is IP, not supply pressure. Higher tank pressure would then increase seat wear only to the extent that it raises IP, and even that's a bit iffy.

There would be more force on o-rings subject to supply pressure and that could accelerate o-ring wear, especially in locations where extrusion is an issue, like the HP piston o-ring in the MK5/10. But not the seat.

With diaphragm 1st stages, the supply force is upstream, so IP tends to drop at high supply pressures. In this case there would be theoretically less seat wear with HP tanks.

But the actual force at the seat/orifice junction is 'seating force' which is basically IP minus whatever force exists that's trying to push the seat/orifice apart. The bulk of that countering force is the mainspring in the 1st stage. Theoretically, a higher pressure gradient at the HP seat should mean a higher seating force, but I don't really know how that would be calculated. It's a good question for Luis, he knows all this crap.....

BTW, valve "ratings" for pressure are meaningless. The valve is not going to explode under pressure. The pressures stamped on valves, at least in the U.S. (where the OP is posting from) refer to the burst disc pressure and can be easily changed. I had an unfortunate argument with an ignorant tank filler about that once....

The 200bar/300bar DIN issue is mostly a non-issue. The two standards were arrived at (so I've heard) to prevent regulators that were not built for HP use to be connected to HP tanks. The 200bar fitting is a few threads shorter; therefore the 200bar male end (regulator) cannot satisfy the 300bar female end (tank valve) because it's length will not penetrate to the necessary depth for a successful connection. The longer 300bar male end, which by the way is on basically all regulators (who would voluntarily choose a short one?) can fill the needs of both 200 and 300 bar valves. How's that for a description?

So get any DIN valve you want, as long as it's a standard 3/4" thread for your tank. And, as has been mentioned, get a valve with a burst disc in the 5000 PSI range for the AL80.

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.