Nitrox Fill Station

[Stone]

Thanks to the contributors to This Thread (http://www.scubaboard.com/showthread.php?s=&threadid=17652&highlight=RIX).

I've been up and running for about two weeks, and just posted a couple of pictures of my fill station on my website. Station (http://www.magnificentrelief.com/nitrox.htm).

I'll add some lessons learned for the small audience that reads this thread.

[oxyhacker]

Up and running! - congratulations. It's very nice - isn't continuous mixing fun? It's one of those things, like the first time you PP mix nitrox, when you finally actually do it, and say to yourself, "Wow - this is really neat". Then, a little while later, "And it's so damn easy!".
Couldn't quite see in the pictures how you are feeding your downstream analyzer, but the dual readout look very slick.

One thing you are missing is a big green and yellow Analox chart, so you can explain to the unintiated why the upstream and downstream don't always agree 100% :-)



Stone once bubbled...
Thanks to the contributors to This Thread (http://www.scubaboard.com/showthread.php?s=&threadid=17652&highlight=RIX).

I've been up and running for about two weeks, and just posted a couple of pictures of my fill station on my website. Station (http://www.magnificentrelief.com/nitrox.htm).

I'll add some lessons learned for the small audience that reads this thread.

[Uncle Pug]

Looks good Stone!
Now you just need to set up a storage bank.

[TwoBitTxn]

Looks great.

Pug, sometimes you remind me of my instructor. Always willing to help me spend my money.

TwoBit

[Uncle Pug]

TwoBitTxn once bubbled...
Always willing to help me spend my money.

Yes I am :D ... And what can we get you to buy, TB?

[Stone]

Probably won't bank until I get an autodrain.

I have a Medical O2 reg that can only supply 5 lpm, so it was inadequate for the mixing reg, and not very good for an emergency O2 tank either. It *is* a perfect supply for the downstream analyzer. I had it on the compressor outlet, but I ordered a block manifold that I will mount on the panel. I'm going to mount the med reg directly to the manifold, along with the gauge and fill whip valve. This will put the fill control, pressure gauge, and analyzers all in one spot at eye level (I didn't care for the gauge and fill valve at the end of the whip).

[omar]

Stone,

That how I have my setup. I also have a couple of quick connects with valves on the manifold so I can use the same fill whip for any PP blending I might do. It also allows me use 2 different pressure banks.

I have 2- 2400psi T's for air and 4-4500 K's for mix and one air. This way I have to manually connect or disconnect the supply line for each and there is no chance of putting the high pressure bank into the low pressure bank.

I have found a new source for a digital pressure gauge that has 0.25% accuracy and costs $199. This is from a quality manufacturer as well. Let me know if you want the info.

omar

[Stone]

Omar,

Let me know about the digital gauges. I bought a cheap 300 psi digital gauge (1%) from Cole-Parmer, but I don't like the auto-off after 3 minutes feature. If I get around to PP mixing over 40%, I'll want a good gauge.

[Spectre]

Stone... If I may ask; what'd the setup run you?

[Stone]

Bauer Oceanus Compressor - $4305 + tax and shipping
Two O2 analyzers - $210
Welding Reg - $60
Manifold Block - $80

The Stik was about $20
Parker QDs were under $20

I also built an O2 whip so I could fill my "D" bottles and a scuba tank.

Pretty hefty up-front investment due to the new Bauer, but my annual nitrox bill was pretty high as well.

[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

[Stone]

I used Vance's book for the Stik, and for my O2 whip, and for the info on orifices I used to modify my welding regulator. . . quite a useful handbook.

[Stone]

Uncle Pug once bubbled...
Both Helium and O2 analyzers feed off of a small regulator at 2lpm

Pug,

Did your Oxycheq fit in the top of the pelican case through pure luck or ingenuity?

[Uncle Pug]

Stone once bubbled...
Did your Oxycheq fit in the top of the pelican case through pure luck or ingenuity?
The Atomox He analyzer came in the pelican box and the oxycheq case fit the lid perfectly. :D