Hangar Project - Oxygen Filling Setup

[Pinecone]

Hydro testing is easy.  Remove the bottle, send out for test, reinstall.  Mine was just done last annual.

 

[wombat]

So.....    I apparently can't click on the correct things, and the part I ordered that I thought was a CGA-540 Male to Scott 9/16-18 Male was actually the wrong gender on BOTH sides.    What the heck?    

So I've bought the correct one, and test-fit everything, being careful to not touch anything with my hands that will be in contact with the pure O2.  

I also bought a CGA-540 to Puritan Bennett adapter for my portable bottle.

Next step: Get my current non-ABO bottle exchanged for a full ABO bottle and refill my onboard tank.

Unfortunately I had very poor oxygen management on my last flight and depleted my onboard O2 to about 100 PSI so it might be worth going ahead and buying a second bottle so I can cascade them.   Or not.

Once I've got that done and have actually done a refill I'll take some pictures and post it here.

[Pinecone]

ONE MORE TIME, there really isn't ABO.  ALL O2 these days comes from liquid oxygen and is 99.99999% pure O2.

[wombat]

While there may be no physical difference between the products labeled as ABO and other oxygens, there are legal differences.

At the very least, you can buy ABO and other industrial oxygen products without a prescription but you must have a prescription to buy medical oxygen.

 

Regardless, I'm not planning on breathing from the tank that I bought second-hand from a random dude off of craigslist, when he said the last time they looked at this tank was about the 2008 economic turndown.   And I guess it remains to be seen how much if any difference there is in the price between ABO and other industrial products.

 

[Pinecone]

Then have the tank inspected.  But it is the same oxygen.

LOTS of articles on this.

https://www.avweb.com/features/pelicans-perch-13getting-high-on-welders-oxygen/

 

[wombat]

Yes, I know the product is the same.     

But also, there is no place around that will refill a tank for me.  I have to exchange the tank.   And they'll take care of any purging and testing of the tank.   

So I'm going to have the tank exchanged because what's in this particular tank right now might be someone's homebrew oxygen concentrator to a compressor made out of an old VW engine that they previously used for chlorine, ammonia, and the covid virus.  

[Pinecone]

OK, I can see that.

But I would just exchange for a O2 tank for welding and not look for ABO.

[wombat]

Industrial Oxygen: $65 exchange

ABO: $250 exchange, and they can get it late next week.

Medical Oxygen: Unknown; they won't quote a price without a prescription.

So I refilled my plane and portable today.

Looking forward to using O2 a lot more often.

[TangoTango]

I'm going to revive this thread instead of starting a new one, as I'm currently ordering parts to build a hangar setup and I'm a little confused by the transfill kits for sale.

Since I'm NA, I use a portable Aerox bottle with a CGA-540 fitting, and I recently leased a 300cuft tank of oxygen with a GCA-540 fitting on it. It seems like I should be able to just buy a clean hose with CGA-540 fittings on each end, attach the two bottles, and modulate the flow with the supply bottle's valve to keep things from getting too hot until the two tanks have equalized.

However, I notice the aviation oxygen equipment suppliers (Aerox, MHoxygen, etc) sell FBO transfilling kits with bleed valves, pressure gauges, and even regulators. Is any of this necessary? 

A bleed valve seems like it would be useful, but an additional pressure gauge seems redundant when the small tank already has one, and I don't understand what would necessitate a regulator on the transfill line since all we are doing is equalizing two tanks, and the speed with which this happens can be regulated with the valve. Can somebody more experienced enlighten me on what is really necessary for those of us that are filling tanks for personal use?

[rklems]

A single bottle refill system will drop down pretty quickly over a few fills to not be putting that much in to the bottle (unless you are using some sort of pressure boosting system, but those are pretty pricey). You are right that you don't want to just dump the O2 from one to the other, you have to modulate the flow to a trickle to keep the bottle from heating up too much. The supply bottle valves are often not that great for small adjustments, they can be hard to turn, can stick, etc (they live a hard rental life). That's where the trans filler setups work. They are designed to make it easy to cascade multiple bottles together, and provide the easy adjustment to slowly trickle in, and the bleed valve is very useful to bleed the pressure off for disconnect. The separate gauge on the transfill setup is also useful for checking bottle pressures, yes in a single bottle systems, the end point pressures should be equal, but the gauge might not be accurate, you might want to know before connecting what the bottle pressure is (it'll change significantly based on the temperature of the bottle). Also, don't forget the pressures involved here, you don't want to close off both valves and still have 2000 psi in the hose that you are slowly backing off the threads until you get to a point that it starts to bleed off the pressure (or the few threads left can't hold back the pressure and rip off and the hose whips in to your face, and the hose and/or bottle is permanently damaged) If you do get a transfill setup, remember that even with the bleed valve, that does not remove the pressure in the lines behind the regulator, only in the interface between the regulator and the bottle being filled, so if you ever swap the bottle(s) out, gotta make sure to open the regulator and bleed those lines too.

[Yetti]

Gauges are important so you don't overfill your bottle.    You might notice that a big tank can over pressure a small tank.  Some fittings will have a small hole drilled in the female that will reduce pressure as you take the fitting off.   

[Scott Ashton]

The bleed valve is handy because there is a lot of pressure behind the nut and it will be very hard to loosen with 2000 psi behind it.  You can crack the nut and bleed it out that way, its just that the bleed valve makes it a little more "elegant".

Definitely do a two-cylinder cascade.  Since you can only fill to equilibrium, it makes your cylinder utilization go much further.  The regulator is handy because it will keep you from overfilling - but not necessary if you are careful.

Make sure you have the supply cylinders either chained to the wall or secured in a rack.    

Fill slowly - about 200psi per minute.  It should take you about 10 minutes to fill a cylinder if you are doing it at the right pace.  Otherwise you will heat the cylinder you are filling up.

At OSH we fill about 20-30 cylinders with two ABO supply tanks and usually have some left over, so it should last you a while...

If you have any trepidation, have a mechanic or someone on the field who has done it before show you the setup.

If you decide to get a transfill setup give me a call and we'll get you a discount code.  

 

Scott

 

 

[Z W]

As an update on this post, I had planned to get a second cylinder at some point to either cascade or just dual-stage fill the O2 in the plane. However, with the Mountain High 02D2 system I added about the same time, I go through the oxygen so slowly, I've found it unnecessary. I just refilled the supply cylinder for the first time. It still had 700 PSI left in it, but I wanted the plane topped up more for a long cross-country with 2 on board.

So, if you're considering doing this, maybe start with one cylinder and see how long it lasts you before you invest in a second one.

I have found having the setup in the hangar has greatly increased the percent of the time I fly on oxygen, and has also increased the average altitude I fly at. I'm in clear smooth air more often and feeling better and less fatigued when I land. All around worth it.