Build your Own Oxygen Setup?

[petehowell]

Dana,

Only change might be to substitute a pediatric regulator - it allows lower flow rates and finer control to stretch the O2 even further. I use a pulse oximeter to let me know when I have the flow correct.

[BlackRV7]

Originally Posted by petehowell

Dana,

Only change might be to substitute a pediatric regulator - it allows lower flow rates and finer control to stretch the O2 even further. I use a pulse oximeter to let me know when I have the flow correct.

Good point Pete. Is my math correct here. The charts list 7.4 hours endurance at 15K on a 425 liter tank. My rough math says the flow would have to be .9 lpm, at 18K the endurance is 5.1 hours or 306 minutes which would require a flow of 1.38 lpm. Am I missing anything in my calculations?

[az_gila]

Originally Posted by petehowell

Dana,

Only change might be to substitute a pediatric regulator - it allows lower flow rates and finer control to stretch the O2 even further. I use a pulse oximeter to let me know when I have the flow correct.

...altitude compensated? I bet they were not designed to work at the equivalent of the peak on Mt. Whitney....

The better aircraft ones supply a higher flow rate and use a needle valve at the flow meters to set the actual delivery to the user.

If you have this system, then a "T" can be used to supply each user if they have a needle valve in each line.

The left hand unit below...




Dana, skip the math....

Set the regulator to the highest flow rate and use the adustable flow meter above - then you will know exactly what you are getting.

[Kahuna]

While the flow meters are helpful, with your home use push on connectors as found with the sytem you selected, restricted flow with the needle valve builds up load pressure on the lines and blows em off.
I find that the use of flow meter works if left wide open, and use the regulator you saw on the listing to control flow, let the little floating ball tell you how much you have going referenced to an altitude number. Then the pulse ox for the cross reference.
Little flowing ball is a nice visual cue you are working as desired.

[az_gila]

Originally Posted by Kahuna

While the flow meters are helpful, with your home use push on connectors as found with the sytem you selected, restricted flow with the needle valve builds up load pressure on the lines and blows em off.
.....

...but why not use good Tygon tubing rated for oxygen and better fittings?

I know they don't blow off in 110 F temperatures in my sailplane with my old Nelson regulator.

If pressure builds up as you say, doesn't that imply that the regulator is not really working? A true regulator will will limit the max. pressure to it's output setting.

Does anyone really know what specifications these medical regualtor devices are really designed to?

Personally, I would prefer to stick to the aviation stuff when it goes into my lungs at altitudes higher than people live...

[Kahuna]

Originally Posted by az_gila

...but why not use good Tygon tubing rated for oxygen and better fittings?

I know they don't blow off in 110 F temperatures in my sailplane with my old Nelson regulator.

If pressure builds up as you say, doesn't that imply that the regulator is not really working? A true regulator will will limit the max. pressure to it's output setting.

Does anyone really know what specifications these medical regualtor devices are really designed to?

Personally, I would prefer to stick to the aviation stuff when it goes into my lungs at altitudes higher than people live...

1. Fittings more expensive, not needed.
2. True regulator? There are all kinds of gas regulators. For medical use, they are flow not pressure. Works just fine.
3. Im sure lots of people know what the exact specs are and exactly what they are designed to do. Given liability issues Im sure its no secret. I never cared enough to look. Dont know or care to know what Im looking for in an oxygen regulator.
4. Personally, I dont care to use aviation stuff all the time. Turn on gas, gas flows, ball flows up to some value, stick in nose, go fly. At 10 cents on the dollar for the medical stuff vs aviation ox items, I prefer to keep the money.

[rvmills]

After reading through this post, and after watching Greg Aerhart put together a nifty semi-permanent O2 install in his RV-9 Tip-up, I worked with Greg to put together a semi-permanent O2 system in my RV-6 Slider.

Pictures below, but here is what we put together (and thanks for the help Greg!...you're up next for pix!)

"D" O2 bottle and regulator: $50 on ebay
Hydrostatic test on bottle: $25 at local fire ext shop
Bottle mounting bracket and hose clamps: $25 on ebay
Flowmeter 1: $20 bought here in VAF class. by Dan (guccidude1) for me...thanks!
Flowmeter 2: $65 from Mt. High Aviation Oxygen
2 quick disconnect female bulkhead fittings: $30 Mt. High
2 quick disconnect male fittings for cannula hose-ends: $8 Mt. High
15' of Tygon tubing: $15 Mt. High
2 Oxymizer cannulas: $50 at a local shop (Mt. High has 'em, same price)
1 "T" fitting for tubing: $5 from a local hose/fitting store

$293 in parts, along with fabbing up brackets for the flowmeters and bulkhead fittings, as well as a cover for the O2 bottle, all out of scrap AL on hand. Eric at Mt. High http://www.mountainhighoxygen.com/ was very knowledgable and helpful when I called to purchase the needed parts! Here's how it came together (just one possible solution, of course!):

Here's the bracket for the bottle installed on the right side of the baggage compartment. Placement was set aft enough to ensure plenty of clearance between the nyloks on the back of the panel and the flap actuator. I'd post the ebay link, but would recommend saving the $$ and making this piece from .125 AL (I traced it and have the dimensions if anyone wants them...or the ebay link, just lemme know). Velcro is for the side panel covers and the bottle cover (shown in later pix):



Bottle installed (old side panel velcro was removed after pic shot):



Closer view of the bottle, regulator and "T". The tubing runs along the seat-back support to each side, then through a grommet to run forward between the arm-rest and panel insert on each side:



After running forward up the arm-rest, the tubing goes into the bottom of the flowmeter, out of the top, then up and under along the canopy rail. At the back of the rail the tube makes a 180 to connect to the quick-disconnect bulhead fitting. Placement of the QD was set to allow the 180 without kinking the hose, while allowing it to hide a bit behind the seat, yet allow for easy one-handed insertion or removal of the cannula connector:



Here's the left side with the seat installed:



Cannula inserted (easily slides in when seated by reaching under the outside arm):



Removal of the cannula is a snap...push up on the release and the male fitting and hose pops out into hand:



Here's a pic of the back of the bottle cover I made, just to make the final install look a little less industrial...perhaps a bit overkill, but kinda fun, using scrap and a "high-tech" workmate and plywood "break" to do the bending. Covered it with some left-over material from the side panels:



Here's the cover installed and the side panels back in:



Last pic, with some gear in the back. Go-bag tool kit fits in front of it, and the regulator is an easy reach in-flight. Cannulas and pulse-ox meter fit in a little stuff-bag (not shown) that tucks nicely between the bottle cover and side-wall recess:



Kind of a fun little project. Desired result was a lightweight (came in at 8.5 pounds total), no-hassle system in which the flowmeters are out of the way but visible, cannulas are easy to insert and remove (and the cannula tubing stays out of the way behind the shoulders), and the regulator is easy to manipulate.

Great info in this thread, and Gil, good info on trapped O2 expansion in the tubing while sitting in the heat. Since the bulkhead fittings do have an internal shutoff valve, the planned procedure will be to turn off the regulator at lower altitudes in the descent, and "breath" the lines empty (till the ball stops floating).

Thanks again to Greg and Dan for the help and ideas!!

Cheers,
Bob

[Mike S]

Bob, good write up, great addition to a great aircraft.

Thanks.

[Kahuna]

I love those quick disconnects.
Well Done. Thanks for the pics.
What happens when there is nothing in the quick disconnects. DOes it block or shut off that line, or is it still an opening?

[rvmills]

Originally Posted by Kahuna

I love those quick disconnects.
Well Done. Thanks for the pics.
What happens when there is nothing in the quick disconnects. DOes it block or shut off that line, or is it still an opening?

Thanks Mike,

The QD bulkhead fittings are available with or without a check valve. $15 ea with, and $12 ea without. On the Mt. High site they are under built-in systems, here:

http://www.mountainhighoxygen.com/in...product_id=404

They make a similar QD (with check valve for $10) in nickel plated brass, but those are 1/8" NPT on the back, versus the barbed fitting on the plastic ones.

I went with the check valves, just in case I forget to shut off the regulator. Hopefully I will always "breath the lines dry" during descent to prevent the tubing "easter eggs" Gil mentioned.

These bulkhead fittings would make for a great panel or sub-panel mount option too. I probably would have mounted them sticking out of the side rail if there was enough room in there to make the tube connection behind it, but there wasn't.

Also received a request for the dimensions on the bottle bracket, so here's a quick drawing, as measured from the one I purchased. Anything close would likely work just fine. (Coming at ya via e-mail Charlie.)



Cheers,
Bob