Advice needed on fill station configuration

[vrocco]

I am relatively new to this and would like some advice on how to configure my home fill station. I got a great deal on a whole setup from a guy that was doing all sorts of partial-pressure blending and filling all sorts of gases. I don't need the complexity of all that, so I want to configure things so that they work for me.

Here's what I have:

-Coltri MCH-16 Compressor (Relief Valve set at 3500psi)
-5x DOT 4500 PSI Storage tanks
-Haskel AGT-15/30 Booster
-Blending Panel
-3x Tall (33"?) Filter Towers
-Various fittings, high pressure hoses, valves, etc.

Here's what I want to do immediately:

-Fill at least 4 tanks with air simultaneously (up to 3442 high pressure steel, but mostly AL80)
-Not run my compressor higher than the 3500psi relief that is currently set (to prolong the life of the compressor)
-Fill 100% O2 for both rebreather bottles and first aid kit (Haskel would be dedicated to this)
-Not replace any more filters than what I need to to provide good breathing air (this isn't a business, while I may fill for friends, the costs will come out of my pocket)

Here's what I may do eventually:

-Add Nitrox stick for continuous blending and possibly bank 32%

Here's what I don't ever want to do:

-Partial-pressure blending (don't want the hassle of O2 cleaning everything, extra filtration, etc)



So recommendations on how to achieve what I need would be appreciated. Should storage tanks be set up as a cascade? Individually? Or in pairs? Or just one big bank of 5 tanks? Where should the fill whips be located in the flow? Where do I need check valves? Should I mess with using the blending panel as a fill panel? Or just buy a manifold and attach whips? Do I need any of the big filters? Or will the compressor filtration be enough?

Any help at all is appreciated. I know there are people here who set up these systems all the time. I'd love to benefit from your knowledge and experience and learn a little more myself along the way. Drawings, diagrams, pictures, etc. are all appreciated.

I'll try and take some pics of the equipment I have so anything I didn't explain well or call by the correct name will be clear. I'd like to use what I have as much as possible, but I'm certainly not adverse to buying extra parts in order to get the setup right.

Thank you in advance!

 

[tbone1004]

way I would do it is here

Compressor out to a manifold block. Depending on which manifold block you have, I would go 2x2x1 for the bottles or individually, doesn't really matter, and then one output to the regulator. Cascade is imperative for efficient filling. If you want to put a check valve on the compressor side go for it. I would put either a check valve or valve valve on the compressor side.
Manifold block out to the regulator
Regulator is to keep you from overfilling aluminum tanks, lp bottles etc etc. This is optional technically, but recommended.
From the regulator is another manifold block with the fill whips. If I were to put a single check valve, I would put one between the regulator and the whips. This part can have the valve at the tank hookup, or can have the valve at the manifold block. Depends on how you set it up, cost, etc etc, but each whip needs it's own valve. I would also put a valve on the end of the regulator so you can control output from a single source. Pressure gauge should be right after the valve so you can see the pressure on the tank side.

Without seeing your blending station, I can't really say how to set it up without seeing pictures of what you have already.

For filling you open the first cascade and set the regulator where you want it to be set. Hook however many tanks you have up and open the tank valves and whip valves to let all of the bottles equalize. Open the valve from the regulator to the whips and fill. When the first cascade is empty, close it off and move to the next. When you hit the second cascade is where you fire up the compressor. Let it run when you are filling since it will help the banks in filling the bottles. As soon as the tanks are full, shut off the valve from the regulator to the whips, shut the valve to the open cascade off, and open up the first cascade so the compressor can start filling that one. The regulator will tell you what pressure the cascades are at if it is under the fill pressure you have set. Disconnect the tanks individually, hook up the next batch and repeat the process. As soon as the first cascade has equalized, all you have to do is shut down that cascade, open the second cascade and continue on. No need to shut off the pressure to the whips since you are going to a higher pressure cascade. Continue on to the third one, etc etc. Once you are done filling, you can shut off pressure to the regulator, and open the banks and let the compressor work it's way up to filling them all at the same time.

If you are filling nitrox, I would highly recommend just building a stick and be done with it. Bank everything at whatever nitrox % you want and if you need air, you can just fill straight from the compressor. Alternatively if you fill more air than blended nitrox, you can fill the nitrox straight from the compressor, to each his own.

 

[vrocco]

Looks like everything came back, not sure what happened there.

Based on tbone's response, I drew up a diagram of a possible setup. tbone is this pretty much what you would do? http://www.roccotechnology.com/files/fill.pdf

Anyone have any other suggestions, caveats, or knowledge to share?

Thanks!

 

[tbone1004]

your diagram is basically what I would do. You don't need the valves at the manifold and the end of the whips, so one set of them will do. The difference is I would have one outlet from the manifold go to the haskel directly and treat the haskel like a tank. With the haskel you want to be able to utilize the banks as a cascade as well so I would just drive it straight from one of the fill whips if you can put a yoke block on it or independently with it's on hard line. Your call there. You will want to build a nitrox stick though because the haskel gets really inefficient when it has to boost significantly, so once you hit like 600 or so PSI in the O2 bottles, you will want to send them straight into the compressor intake for nitrox which will suck them dry.

I don't know what the back of your blending panel looks like, but if those are a pair of regulators, you can just use that for the regulators. Alternatively you could put the manifold up to both sides of it and have the ability to fill steels and aluminums at the same time at different fill pressures.

 

[Brandon]

If you're in Vegas, Rocco - get in touch with Bill Bradley. He's a technical instructor and teaches blending courses. There's a system with all the same components as yours running over at Scuba Views, and he teaches out of that shop. He'll be able to help you get things set up as efficiently and safely as possible, and teach you how to use it effectively. He's very reasonable. PM me for his contact info if you'd like.

-B

 

[vrocco]

Here's some pics of the back of the panel. They are two separate regulators. I like tbone's idea of being able to fill two different pressures at the same time (or run the Haskel on one and fill tanks on the other). So I think I could bring the cascade manifold into another small manifold that then goes out to both regulators. I'll replace the little 600psi gauge with a 5000psi guage to show the pressure coming in. I then have a valve on the panel between that manifold and each regulator. I probably even have room to T the outputs on the bottom and put 4 whips on each regulator. I'm not sure I need that many at once right now, but we'll see where it goes.

I'm assuming from your post that the compressor filtration is sufficient for only filling air and (eventually) continuous blending? I don't need to use any of those extra filtration towers?

 

[A+ Compressor]

I concur with most of what tbone said with just a couple of differences. I would not allow equalization of all of the whips. The reason I would not do this is that if you happened to get one contaminated tank in with higher residual pressure than other tanks you may be filling, the contaminated gas could contaminate the other tanks, too.

I would set up your cascade with each bottle individually. That configuration will give you the maximum number of fills before you need to run your compressor.

Tbone is correct - your Haskel is a horrible energy hog but a necessary one unless you have the money to spring for an electric drive booster. They are also dangerous and more so pumping 100% oxygen. Personally, I think every one should be placed in a bomb box. A good friend of mine and customer, Wayne Kinard at Amigos Dive Center had a knob twisting customer crank up the drive pressure because he thought Wayne's Haskel was running too slow and blew up the drive area, totaling the unit. Luckily, no one happened to be in the line of shrapnel fire. They can also blow up if they aren't serviced and oxygen cleaned regularly. The pic of your Haskel shows what appears to be a good condition unit. Don't let it go more than 3 years of infrequent use without cleaning by a well qualified technician. For a busy dive shop, annually is required for safety and best efficiency.

Filtration-wise, the single combination purifier at the compressor is adequate but if you're pumping a lot of gas, the cost of replacing the small filter frequently will get you down. A larger purifier tower can filter more gas in proportion to the cartridge cost than a small one. As a safety, you should have at least a bulls-eye combination CO/H2O sight glass after the purifier and LOOK at it after each compressor run.

 

[tbone1004]

I agree that individual cascades and individual whips are ideal, but also adds a lot of expense and if you are filling personal tanks it's a tossup. What I posted above is what I'd personally do, but basically all of my tanks are used and filled in pairs, so backgas, stages, etc etc. With that panel I'd have one where I could fill the aluminum bottles, and the other where I'd fill my backgas. Problem with true isolation is you have to have check valves everywhere which I think is somewhat impractical but YMMV

 

[OkByMe]

I mounted everything needed to control and fill on a sheet of plywood bolted to a uni-strut frame on the front of the compressor. A flexible hose with a high pressure dis-connect at the high pressure manifold valve, connects me to the cascade line. That way I can dis-connect from the cascade and take the compressor with me on a trailer with my tanks and other gear. The helium cylinder is inline with the cascade lines with a check valve protecting it from the higher pressures in the line. I dump the SCUBA tanks, fill helium for a mix and dump nitrox on top. Mix is determined from a chart. I found trying to run both oxygen and helium through the compressor is too problematic since Trimix is too dynamic. I have Oxygen concentrators to plumb Oxygen into a stick and then on to the cascade. I have a schematic of the layout appended along with some pictures of the compressor.

I suggest you fill only from the cascade and use your compressor to fill the cascade. That way you can pick a low temperature - low humidity day to run the compressor with a fan turned on it to get the best life out of it. It may run a couple of hours or more, which is easiest on it. Your filter stack is fully saturated and condensate has to be drained less. Mine is a 2006 and is still like brand new.

I don't know what you are going to do with the booster unless you have concentrators and want to boost that output into a cylinder for 100%. You always trans fill Oxygen to a SCUBA cylinder from the source for 100%.

 

[OkByMe]

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