300 Bar 12L or 232Bar 15L ?

[Big Chris]

I am looking to buy my first diving cylinder

I tend to use a lot of air so I am looking at buying a larger cylinder.

Taking advice on the advantages/disadvantages of getting a 300 bar 12L or maybe a standard 232 bar 15L.

They have equivilant air amounts so just wondering if there were any extra things i would need to consider if i buy a 300 bar cylinder.

Any advice greatfully recieved

Thanks

Chris

 

[scubafanatic]

Hi Chris,
I too am a fellow air-hog....you're not alone! The main thing is it will be a lot easier to get your 232 bar tank completely filled..........it's almost impossible to get a 300 bar tank filled...at least in the USA.

I dive 19 and 20 liter tanks....my 'small' tanks' are 13 liter tanks....most of them are only 180 bar (2640 psi) tanks...I have a couple high-pressure tanks, but even those are only 232 bar tanks (3500 psi).

Most places in the USA only fill to 3000 psi......only some will even fill to 3500 psi....the only place to get anything like a 300 bar fill in the USA are cave diving areas....some will fill up to 5000 psi.


Karl

 

[Phoenix]

I would go with the 15l 232 bar

your getting a little less air in the 15
but your more likley to get a decent fill
you will put less strain on all your regulators and hoses,
and it will weigh a damn lot less

atleast, thats what I believe based on what I have been told when I too researched into getting tanks
Im sure some of the more profficient people here could give you more detailed advice

 

[sheck33]

my choice would be the 15l 232 bar cylinder for the reasons listed above.

 

[Ari]

Reasons are:

1. It is not easy to get a 300 be refils. Not every filling station will do this.

2. It is a very, very negative tank both at the begining and the end of a dive. In certain conditions this might be a problem.

Ari

 

[dlegros]

I would go for the 232 bar 15l as well.

I am no physicist (would one kindly step in here) but because of Van der Vaal's forces, the ideal gas laws go screwy not soon after 232 bar and you don't get the air gain you would expect.

(According to Nigel over on uk.rec.scuba - and he seems to know his stuff)

You also need to consider your kit - you can only get 300b on DIN connections, so if you have a reg that is A clamp and not easily converted...

HTH

Dom

 

[Big Chris]

cheers for your help guy's

Think i will go for the 15L cylinder as there seems to be quite a few drawbacks and also i dont have DIN regs which is a problem. I also found out that the standard A-clamp was originally only rated to 207bar. Now they have added a "bit more metal" to make it usable with standard 232 bar cylinders !

I did enquire at a few dive sites about 300bar fills and didnt get many saying they could or would fill them.

Cheers again

Chris

 

[dlegros]

Chris,

Here is a link to Nigel's page on Van der Vaal's force:

Van der Vall's force by Nigel Hewitt of UKRS

Dom