SCBA carbon tanks

[TDK]

You can plug any tank and fill pressure combination into this calculator and have all your questions answered: https://sye.dk/airgun/

9L is the biggest carbon cylinder commonly available in the US and they weigh around 4.9kg without valve. I highly recommend this size. The 12L Alsafe carbon cylinder mentioned above is rare, and may be a unique offering from them. I also have a 12.9L steel tank from when I first started, and you are correct, those are not fun to move around at all!

I couldn't agree more about physical volume (in Liters!) being the way all tanks should be described. I don't mess around with capacity at all. There is no better example than the 9L SCBA tanks which retailers use their own physics interpretations to advertise from 87 to 100cu ft capacity.

 

[Chickenthief]

You can plug any tank and fill pressure combination into this calculator and have all your questions answered: https://sye.dk/airgun/

9L is the biggest carbon cylinder commonly available in the US and they weigh around 4.9kg without valve. I highly recommend this size. The 12L Alsafe carbon cylinder mentioned above is rare, and may be a unique offering from them. I also have a 12.9L steel tank from when I first started, and you are correct, those are not fun to move around at all!

I couldn't agree more about physical volume (in Liters!) being the way all tanks should be described. I don't mess around with capacity at all. There is no better example than the 9L SCBA tanks which retailers use their own physics interpretations to advertise from 87 to 100cu ft capacity.

Thewre is a reason for that!

9liters at 300bar = 2700 liters of air true volume.

Converted to cft that is 95.34 true volume

100cft is 2833liters and is equal to a 315bar filling.

The 87cft comes into play if you factor in the whistle pressure of roughly 50bar or 725psi. When pressure drops below that a whistle in the tank starts and that alerts the fireman that it's time for a refill. http://breatheair.com/2017/11/09/scba-cylinder-breathing-duration-calculation/

315bar - 50bar = 265bar equal to 2385liters or 84.3cft.



Now the biggest alu/CF bottle in Europe is a true 9 liter from Best Fittings.

https://www.bestfittings.co.uk/shop/airgun-charging-equipment/cylinder-accessories/9-ltr-carbon-fibre-airgun-charging-cylinders-300-bar/



When you go to 12 liters it's a steel body in CF wrap.

https://www.diveavenue.com/en/dive-tank-di-carbon-tanks/1257-12-liter-carbon-tank-carbondive-300bar-single.html

 

[steve-l]

Chickenthief, 

Thanks for the tip on the wasted volume of the low air whistle, but not all 12 liter bottles are steel. The one below offered on Aliexpress is 6061 aluminum with a carbon wrap. 

https://www.aliexpress.com/item/33004875680.html?spm=a2g0o.store_pc_groupList.8148356.9.85d03941Sgsm1A

This bottle made by Acecare also incorporates the standard thread of M18 x 1.5, where that steel/CF bottle uses M25 x 2.0. You may also note that this same bottle is offered with different valve configurations and at different prices accordingly. I particularly like their fill valve offering because it has a separate pressure gauge for bottle pressure. This would be very handy in determining when to recharge the bottle. Another note is the weight difference between the carbon/steel (10.9 kg) and the Acecare alu/CF (6.9 kg). This bottle is made in Taiwan not on the mainland. I do not have an interest in this company, but it is the best 12 liter bottle for PCP I have found yet. I am still not very happy with the cost. If any of you folks find anything better, please let me know.

 

[steve-l]

As a follow up to this thread, I have purchased the Acecare 12 Ltr bottle with the filling station valve setup along with a pair of rubber boots. They are scheduled for delivery in March. I will not be filling this bottle beyond my previously stated 234 Bar max pressure without a gun with 2 regulators, so the larger volume of 12 ltrs. over the 9 ltr. size is required. The advantage for me currently is only weight and that is huge at 6.9 kgs.

Let there be no doubt that air is the most expensive element of this hobby!