Luxfer 4350Psi AL Tank?

[WarmWaterDiver]

I understand what you're saying, I just wasn't aware that there was a breakover non-ideality shift at 250 to 260 bar. So it really looks like the 3500 or 3442 PSIG steel tanks offer the optimized fit of volume and mass availability based on your experience?

 

[Nostromo]

I understand what you're saying, I just wasn't aware that there was a breakover non-ideality shift at 250 to 260 bar. So it really looks like the 3500 or 3442 PSIG steel tanks offer the optimized fit of volume and mass availability based on your experience?

So this is due to the difference between real and ideal gasses?

e.a.e.

 

[KOMPRESSOR]

I don't get it either... If you lose 10% where does it go?

e.a.e.

Well, first of all you never get it into your tank in the first place, so it doesn't go anywhere. But filling your tank with any more than say 260 bar doesn't give you very much extra breathing gas.

Say the 40 bars from 260 to 300 bar in a 10 liter tank should idealistically be 400 liters. But in reality this extra pressure only gives you about 200 liters. In practical diving this shows in the way that if you drop in with 300 bar "cold", your gauge drops like crasy to about 270 bar. And I'm not talking about the effect of the temperature drop.

This is well known over here since 300 bar tanks are so common. I suppose it's not an issue in the US, since you guys seem to think of 300 bar tanks in the same cathegory as explosives...

 

[KOMPRESSOR]

I understand what you're saying, I just wasn't aware that there was a breakover non-ideality shift at 250 to 260 bar. So it really looks like the 3500 or 3442 PSIG steel tanks offer the optimized fit of volume and mass availability based on your experience?

ABSOLUTELY!

And I just switched my 300 singles to 232 bar doubles. :14:

 

[Nostromo]

I Googled a bit, and found this:

http://www.combro.co.uk/nigelh/diver/vdw.html

which seems to explain a few things.
e.a.e.

 

[KOMPRESSOR]

I Googled a bit, and found this:

http://www.combro.co.uk/nigelh/diver/vdw.html

which seems to explain a few things.
e.a.e.

Just as I would have explained it myself!

 

[Nostromo]

Just as I would have explained it myself!

Yeah, I don't know why you didn't just write that to start with, rather than confusing everybody...

 

[teknitroxdiver]

If that statement is true (I have no clue if it is or not), then it's because above a certain pressure, air ceases to behave as an 'ideal gas', that is, it doesn't act like logic says it should.

 

[KOMPRESSOR]

If that statement is true (I have no clue if it is or not), then it's because above a certain pressure, air ceases to behave as an 'ideal gas', that is, it doesn't act like logic says it should.

I can say as much as that this is correct. It's "common knowledge" among divers in Norway since we have a lot of divers using 300 bar tanks. It's even explained at any PADI OW course. Although not many of us can explain WHY. Neither can I. But so it is.

 

[Leadking]

I looked at bringing 300 bar cylinders to the U.S. market about 4-5 years ago and after reviewing the buoyancy characteristics abandoned it. They are so negatively buoyant that when diving anything that the U.S. market was accustomed to meant having to use a lift bag WHILE you dive.
Talk to any diver that used a Heiser cylinder!

Lee