Home fill station for dummies?

[tbone1004]

@stuartv the homefill is a 3-stage compressor similar to a Rix Microboost but a lot less "industrial". It is fed by an oxygen concentrator that uses zeolites to remove the nitrogen from the atmosphere. Since it is only removing the nitrogen, the oxygen is concentrated along with everything else that is in the atmosphere which is mostly argon. You end up with somewhere around 95% O2 and 5% argon. Since the argon is not concentrated in your other breathing gas, you can consider the gas 100% when using it for deco. It's the only way nitrox is generated in many parts of the world, and this technology is used for a lot of military operations in remote locations.

I second @rddvet 's comment about grabbing a couple big bank bottles and prioritizing a booster over a compressor. If you get a 2-stage booster like an AGT-15/30 it has a minimum inlet pressure of 50psi. You could get a diaphragm compressor like the California Air Tools for a couple hundred bucks and put a dryer on the end of it and you'll get breathing grade gas, then put a filter on the outlet of the booster and get breathing gas out of it. I know rddvet is using a Masterline but I think they don't like less than 1000psi inlet gas or you could do it with one of those. If you do it with a MAsterline it is critical you have a VFD though because you need to slow it down to match the outlet of the low pressure compressor.

 

[rddvet]

@stuartv the homefill is a 3-stage compressor similar to a Rix Microboost but a lot less "industrial". It is fed by an oxygen concentrator that uses zeolites to remove the nitrogen from the atmosphere. Since it is only removing the nitrogen, the oxygen is concentrated along with everything else that is in the atmosphere which is mostly argon. You end up with somewhere around 95% O2 and 5% argon. Since the argon is not concentrated in your other breathing gas, you can consider the gas 100% when using it for deco. It's the only way nitrox is generated in many parts of the world, and this technology is used for a lot of military operations in remote locations.

I second @rddvet 's comment about grabbing a couple big bank bottles and prioritizing a booster over a compressor. If you get a 2-stage booster like an AGT-15/30 it has a minimum inlet pressure of 50psi. You could get a diaphragm compressor like the California Air Tools for a couple hundred bucks and put a dryer on the end of it and you'll get breathing grade gas, then put a filter on the outlet of the booster and get breathing gas out of it. I know rddvet is using a Masterline but I think they don't like less than 1000psi inlet gas or you could do it with one of those. If you do it with a MAsterline it is critical you have a VFD though because you need to slow it down to match the outlet of the low pressure compressor.

inlet pressure minimum is 300psi. I love my masterline but it’s not budget friendly. I would get one of the USUN’s at this point. They’re track record is getting better and better.

 

[stuartv]

@tbone1004 Thanks for the info!

I understand now about the Homefill setup. And I think I will pass on that route. I just don't like the idea of having that much argon in my mixes. I don't want to find out the hard way about some edge case where having that argon there screws me up somehow. I also don't like the idea of having a significant amount of argon in my mix that I can't directly analyze to verify how much is there. Getting a big cylinder of O2 from a commercial supplier seems like a reasonable way to go.

What you said about the home setup and possibly using a CAT compressor to make breathing gas makes perfect sense. Except...

Questions:

I looked at the CAT website. How you tell which compressor is a "diaphragm compressor"? Do you just mean one that is "oil-free"?

Why not put the filter on the inlet to the compressor? You said put it on the outlet of the booster. So, the filter would be filtering (as much as) 3500 psi gas?

If I set things up this way, wouldn't it then be fairly easy and inexpensive to do continuous mix blending into the inlet of the CAT compressor? Say, to make 32% to boost into a bank?

 

[tbone1004]

inlet pressure minimum is 300psi. I love my masterline but it’s not budget friendly. I would get one of the USUN’s at this point. They’re track record is getting better and better.

They are sending me a 15/40 to check out and evaluate. If it works, it's a $5k max investment to get it fully set up and that's a no brainer to me.
$1800 with shipping and a spare rebuild kit for the booster
$1000 for misc adapters, whips, gauges etc
$1000 for this compressor and an external filter to feed the whole setup.
California Air Tools 9010D Ultra Quiet & Oil-Free Air Compressor
$1500 for a Shelden external filter setup. For this you really are only drying it the rest of the way, but it doesn't hurt.

That's about the price for a reasonable compressor only, but is way more versatile if you don't need large volumes of gas.

Argon isn't an issue, but O2 is cheap from the big suppliers, but the homefill is nice because you can just plug the tanks straight in and it does compressor duty so to get essentially pure O2 at 2200psi for $500 is quite nice.

All of the CAT compressors are oil-free and low RPM and most are diaphragm pumps. You need a low pressure filter on the inlet side to get as much water and particulates out as you can, but then need a HP filter on the outlet of the booster because you knock a lot more moisture out at the high pressure side with dwell times and the higher pressures themselves.

You could feasibly make an O2 stick on the inlet of the compressor yes, though if you do that I would probably recommend getting a pair of compressors, one to feed with the stick and the other to drive so you aren't wasting O2.

 

[stuartv]

You could feasibly make an O2 stick on the inlet of the compressor yes, though if you do that I would probably recommend getting a pair of compressors, one to feed with the stick and the other to drive so you aren't wasting O2.

Yeah, I already have a big Husky shop compressor I was thinking I could use for drive gas. But, it does use oil so I don't think it would be suitable to produce breathing gas to feed the inlet of a booster.

 

[tbone1004]

Yeah, I already have a big Husky shop compressor I was thinking I could use for drive gas. But, it does use oil so I don't think it would be suitable to produce breathing gas to feed the inlet of a booster.

with enough filtration it can, but as cheap as some of those are, I'd just grab one, put an extra filter on it and call it a day. You will need to give that big Husky a beefy filter system though. I've linked a few on here, but the good thing is that everything else you use with it will appreciate it as well.

 

[stuartv]

I have to close on my new house, move, and then spend some time and money and lame-ass BS crap like paint, carpet, and furniture (LAME!). But, I can see now that my priority right after that needs to be a booster. After that, I can figure out whether to get a compressor, what kind, etc.. Still a few months away, at least, on the compressor question.

Thanks!

 

[broncobowsher]

Staurtv, I have just about the same setup you have. I think you even have a rEvo. like I do.

My setup. Shop air compressor for drive gas. Add a dryer. I use desiccant pellets and dry them out in a toaster oven from time to time. When the color change isn't working so well, new media. The stuff is cheap enough on amazon. https://www.amazon.com/gp/product/B06XYW2LDC/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 for example.

I still see my dive shop for air fills. No doubles, but a pair of 100s. That is the air that is used to top off the mix in the bottles or fill the drysuit bottle. It's clean, the booster just moves it.

At the moment I have 2 bottles each of O2 and He. I'm about to the bottom of the He that the booster can move. I'll soon boost that into a spare AL80 and that will be my baby bank. The O2 is cheap enough I probably won't bother and just send it back with some gas in it.

As for a class to do this. Self taught and just think about what you are doing. Isn't that hard. Use care. You already have a mixing class, that puts you ahead of me. Don't need a dive compressor or try to take a shop compressor and make it clean enough to boost. Just use your local dive shop. You really won't use that much dive air. Shop compressor air, yes you will use a lot of that.

 

[JahJahwarrior]

Tom, cannot wait to hear your opinion on the Usun and your input in setting it up for rebreather bottle fills.
I'm eyeing the GBD40-OL, and already warming my wife up to the idea of having a few o2 and helium bottles hanging out in the corner of the garage.

 

[stuartv]

How does it work as far as the big cylinders of O2 and He?

I assume you find some local commercial supplier, like Sierra Airgas or something, and get the big cylinders from them? Do you have to buy your own T cylinders to start and then trade in empty ones for full ones? When they sell you the gas, they "rent" you the T-cylinder until it's empty and you return it (when you then get a new, filled one)?

Do you take your own cylinders to them and they fill them and give them back to you?

Can you get a T cylinder of EAN32 from a supplier like that?

How much does all that cost?