Cylinders for a Meg?

decoweenie

Stuart,

AFAIK, US-specs state the tank capacity in cf under a certain rated pressure. So for example, a 19cf "standard" pressure would have the same gas capacity as a 19cf "low" pressure IF both tanks are filled to their rated pressures respectively.

But if you fill both tanks to same pressure, then the capacity is different. In another word, their water displacement volume is different.

Metric-specs state the capacity per water displacement/containment. So a 3L 200bar and a 3L300bar would have the same capacity at same pressure.

So your 3L (and assuming 200bar) would have:

(3)(200) = 600 free L
(200)(15) = 3000 psi
(600) / (28.3) =~ 21 cf @ 3000 psi

I am sure I will be corrected if I am way off...

Decodiver

I use dumpy steel 3s on my unit now, and also the longer steel 3s as per the Inspiration.

Changing between either creates no need to change weighting etc.

What I prefer about the steels is that they are not as buoyant as the Ali cylinders some people use on their breathers.

Cheers,

Dave Cooper.

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Rebreather World Terms & Conditions

scubadan

1 Liter = .11 CuFt
Of course you measure inside volume at 1 atmosphere.
Your 3l holds 17.7 CuFt at 2400 psi

divingabe

That is why they are called 19"s with the 10% overfill to 2640psi they hold 19.4cuft.

Overly complicated.

PS tank of choice steel faber 19's

MikeH

The 3l steel Fabers are called Steel 19's here in the US. They hold 19 cubic feet at 2640psi(~180 bar), their rated pressure in the US. The cylinders are called 3l because they hold 3l of water.

To figure out the cubic feet of gas from l's, first figure out how many cubic feet of water the cylinder holds(use http://www.onlineconversion.com/volume.htm). Then multiply the volume in cubic feet by the pressure(in bar), and you have the cubic foot volume of the cylinder.

Clear as mud?

Mike

Benthic

I'll cast another vote for the steel Faber 19cf cylinders. I use them and think they're great! On a recent trip to Mexico, I wound up using aluminum 19s and didn't like them nearly as much. They're lighter and I felt butt heavy. Of course some adjustment may have lessened that effect. I think the weight is more evenly distributed with the steel cylinders.

In any event, I find the 19s will easily last me for 3-4 hours on a single fill, and I'm still very much a newbie at all this Rebreather stuff. I'm hoping that as I get better at buoyance and loop flushing that will stretch out a bit.

Brian

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Steve

My vote is for 2 litre 300bar jobbies. Small, easily enough gas for most situations and rare as rocking horse poo.

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mverick

I have 6 3l fabers. I was thinking of the 30 and 40 Worthingtons but somebody mentioned the extra width and I'm trying not to widen things. SO, if I need more O2 or Dil. I just sling it and plug it in. Keep the rig tight that way.

scubadan

Good point. Thanks.

Flup

I use 5 liter steel faber on my meg and i like them so far. Got two sets of those fabers and with 1 set i can easely make up to 6 dives (up to 40 meters) before needing to refill.

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