300 bar?

[philo]

Hi all what is the biggest bar pressure cylinder that's available please

[Neil54]

450 bar I believe.
Getting it filled is another issue as a lot of places don't have a compressor man enough.

Try midland diving for info.

[angrybear]

300bar is the maximum for breathing air which is all that PCP's should ever use,
however other gasses can go up to 6000psi which is 400bar but those are big industrial cylinders.

[Antoni]

My understanding is that above abt 300 bar air stops behaving like an 'ideal gas', and so the effort and pressure needed to add more air above that pressure rises very quickly for the amount of extra air put into the tank, and therefore the tank needs to be even stronger - hence no point going above 300 bar with air. The air no longer follows the general gas equation in my sig file.

Which is partly what AngryB said above.

[JerryD]

As said, most breathing air compressors top out at 300bar. Be careful of the 450bar marked on air cylinders - that's test pressure, not working pressure.

It would be cheaper to get more 300bar cylinders than to try to go higher.



.

[rapidresponse1]

aye 300 bar

[Steyr]

The option to buy a compressor is very realistic nowadays.

[Rich]

Antoni is on the right lines, but the non-linearity starts to be significant soon after 232 bar and by the time 300 bar is reached, the effect is around ten percent.

By that I mean 300 bar indicated on the pressure gauge means there is about 270 bars worth of air in the cylinder, the rest of the indicated pressure comes from the fact that the molecules are pressing against each other; you might imagine passengers trying to board an already crowded tube train as a visual metaphor.

The work done in compressing the air at these levels can't be recovered for firing pellets out of airguns.

[Dodger21]

I think the 450 bar is the test pressue used when the bottle has a full test.

[angrybear]

The test pressure is 150% of the safe working pressure (SWP) but the Cylinder class is it's SWP.

so 300bar is the maximum for air, there's no need to confuse matters by referring to anything above that.

[Jesim1]

You have all your answers above, so now you know that realistically 300bar is a max for our purposes, then it's down to the size of the cylinder, but you have to be aware of the weights involved, as big 300 bar cylinders are very heavy. For example, each liter of compressed air at 300bar is roughly 0.3kg, so a 12L cylinder has around 3.5kg of compressed air in it, and the cylinder and whip weigh roughly 20kg to start with, so your looking in the region of 24/25kg just for a 12L 300bar cylinder

Also look at carbon cylinders, they are expensive, but a lot easier to handle if your moving it about.