Nitrox Fill Station

[Scubaroo]

But at those prices, did you consider a CCR at all? Or is that something you just want to stay away from?

In Australia, the consensus seems to be, once your diving progresses to the point where you want to look at home mixing, or trimix diving, it's cheaper to get a CCR because of the ridiculous cost of gas down under.

 

[Stone]

Scubaroo,

My nitrox bill is high because both my wife and I dive a lot (and sometimes with the kids). If I went the CCR route, I'd have to buy two.

 

[BlueWaterDiving]

How long dose it take to fill a AL. 80

 

[Stone]

. . . 20 minutes for an empty AL80.

Our tanks usually have between 500 and 900 psi left, so a normal fill takes 12-16 minutes.

 

[Divesherpa]

Stone, that's a great looking Nitrox setup.

Pug, how do you handle the Helium addition? How do you have your analyzers setup to check the mix? Is it all pre-compression?

Cheers

 

[Uncle Pug]

Divesherpa once bubbled...
Pug, how do you handle the Helium addition? How do you have your analyzers setup to check the mix? Is it all pre-compression?

The helium enters the blender on the opposite side of the venturi from the O2. All of my analysis is post compression and takes 2 minutes for adjustments to show up. I pretty much have it dialed in though so I just set it according to the tape markings on my flow gauges and tweak it during the fill.

Here is the blender... the He feed is on the left and the O2 feed is on the right.

 

[Uncle Pug]

Both Helium and O2 analyzers feed off of a small regulator at 2lpm

 

[Uncle Pug]

are marked with tape to indicate settings for various blends. Tape on left is for Nitrox... tape on the right is for Trimix.

 

[Stone]

Instead of a needle valve and flowmeter attached to the welding reg, I screwed in a spare #77 medical orifice w/ nipple. This would not give me enough flow, so I used the orifice formula in Oxyhacker's book. The formula said I needed an orifice diameter of .042, and as luck would have it, a #60 drill bit is .040. By replacing the 120 psi gauge with a 30 psi gauge I have excellent accuracy and repeatability on flow settings (which doesn't matter quite as much when you have a down-stream O2 analyzer).

 

[ericfine50]

Stone,

Very sweet set up. I am guessing you used Vance's book for the Stick?

Nice work
Eric