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Build your Own Oxygen Setup?

> "but will the regulators work correctly at high altitudes?"

I got through to a technical person at Precision Medical where the Easy Pulse 5 you mention is made. The answer is "yes", it will work fine above 10K. The reason they put 10K on the spec sheet is because they test their products within specific ranges and in the case of their medical regulators they don't expect the user to normally go any higher than 10K.

So that concern is put to rest, at least in my mind.

This and the other pneumatic pulse regulators are really a fine solution for stretching the oxygen supply and avoiding waste. Getting a tank re-filled "on the road" can be a hassle so an oxygen conserving regulator such as this EP5 seems like an excellent idea.
 
If you'll be refilling the system somewhere other than from your own refilling station, at the airports where I've bought oxygen the cost is for the whole refill. You don't pay for oxygen, effectively, just the labor. So it's cost-effective to have the largest bottle that suits the plane and your operation.

Next, individual flow-meters, valves and cannulas work great. The cannulas are limited, I believe, to 18,000 feet, though.

Finally, those finger-tip oxymeters are excellent. Rapid feedback to your own oxygen usage. Strongly recommended.

One last thought, if you're building up a system, is that the hoses ought to be compatible with pure oxygen, eh?
 
rvmills said:
"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



Cheers,
Bob
Click to expand...

Do you have a picture of the mounted bulkhead fittings?
 
PR,

I don't have a photo (actually that was Bob's list, but mine is similar). I just mounted a small piece of angle Al on the roll bar (tipup - if a slider, you might have to find another place) that has two holes of the correct size and put the bulkhead connector through the holes. You could mount similarly wherever is convenient. Mine is on the rollbar to the right of center so it is easily reachable in flight (rather than behind me, which is difficult to reach). I have both disconnects in the same place and the cannulas just hang from there.

I can take a photo tomorrow if this isn't clear.

cheers,
greg
 
prporter said:
Do you have a picture of the mounted bulkhead fittings?
Click to expand...

PR,

Take a look at post 87, page 9 of this thread for some pics I posted. you can see the fitting in pics 2,4,5,6,&7. Best shots are probably 6 and 7. I'm about to jump on a jet heading east, or I'd post more now. Let me know if that give you the info you need.

Super easy to install and use, nice little gadgets. I did little angle brackets like Greg...heck, I stole the hole idea from him! Mine are placed differently, since mine is a slider and his is a tipper...but the idea is the same. As far as positioning the fittings...I like mine where they are for the aspect of having the tubes go behind pilot and pax's outer arm and up the back of the beck to the canula. However, they may be a little far back, as it can be a bit hard to connect them in flight. Doable, but a little bit of a twist. Easier to remove in flight, as they spring out when you push on the release. If you go this direction, just play with them to get a comfortable position.

Cheers,
Bob
 
Bottle Location

All,

I note everyone puts their bottles in the baggage area. I'd like to use O2 but have the bottle up front, say under or behind the panel so as to keep the C of G forward (it's a six). Any opinions on putting a bottle there or am I asking something dumb?
 
JackW said:
All,

I note everyone puts their bottles in the baggage area. I'd like to use O2 but have the bottle up front, say under or behind the panel so as to keep the C of G forward (it's a six). Any opinions on putting a bottle there or am I asking something dumb?
Click to expand...

I know of a six that had his engine compartment fire extinguisher bottle by the battery box (old design, aft of the firewall), so all things are possible. You'd have to check accessibility for turning it on and off. My 6A has an 0360 & Hartzell prop, so the oxy tank behind the seats actually helps with the weight & balance.

L.Adamson --- RV6A
 
I would suggest that you find out the weight of the O2 bottle etc. and do the C of G calculations. You may find that it doesn't really shift it forward that much and might not be worth the extra trouble.
 
OK Folks,
After much reading here/elsewhere and internet searching I have decided to build my own Oxygen system comprised of a:
--"D" cylinder with standard CG540 valve and pressure gauge,
-- 0- 4 LPM regulator with good low flow selections (0.25, 0.5, 0.75, 1, 1.5, 2, 3, 4 LPM)
-- Oxymizer style cannula,
-- Blood oxygen saturation monitoring.

So below is what I ended up with, All new and no eBay purchases. If I need a two person setup I will just need to purchase a "Y" splitter (<$5.00) and another Oximizer and flow meter. Total cost $191.20

Too expensive?
Well, since the regulator has click settings for flow, you could remove the flow meter from this setup and save $25 and if you didn't want the cylinder gauge and could live with the medical valve you could save an additional $30, bring your total for simple-single person system down to only $136.20!

Of course, after purchasing all of the parts I found an easy one stop purchase which comes close but without the low flow rate (starts @ 0.5 then goes to 1.0 then 2 etc. LPM) and Blood Oxygen monitor (which you can still buy separately) and flow meter from Chinook Medical for $138.80 part #06741.
--This system includes:
- One Aluminum Cylinder "D" (with toggle valve)
- One Regulator (with click dial from 0.5 to 15 liters per minute, unibody yoke, CGA 870 connection, pressure gauge)
- One Oxymizer (oxygen conserving device for on-demand, low concentration delivery)
- One Non-Rebreather Mask (with reservoir for high concentration delivery)
- One Nasal Cannula
- One Backpack

Bottom line?
-- I think I have found about the Cheapest, NEW, Medical Quality oxygen equipment available to fit for our flying oxygen needs.

Cramer Decker Medical, Inc.
Y540MDG MD Medical Oxygen Cylinder $38.95
w/ Low Profile CGA 540 with Gauge (add $30) $30.00
AREG5404 CGA540 Regulators - 0-4 LPM CGA540 $39.95

Chinook Medical Gear, Inc.
Oxymizer 06502 $17.40

Ingen Technologies, Inc
Oxyview 0-3 l/m # 203A Flow monitor $24.95

Pulse Oximeters Direct.Com
LM-800 Pulse Oximeter LM-800 $39.95

Total: $191.20

See links below:
http://www.cramerdeckermedical.com
http://www.chinookmed.com.
http://www.ingen-tech.com
http://www.pulseoximetersdirect.com
 
Thanks

BillC said:
OK Folks,
After much reading here/elsewhere and internet searching I have decided to build my own Oxygen system comprised of a:
--"D" cylinder with standard CG540 valve and pressure gauge,
-- 0- 4 LPM regulator with good low flow selections (0.25, 0.5, 0.75, 1, 1.5, 2, 3, 4 LPM)
-- Oxymizer style cannula,
-- Blood oxygen saturation monitoring.
(deleted stuff in between to save space, M. Burns)
Total: $191.20

See links below:
http://www.cramerdeckermedical.com
http://www.chinookmed.com.
http://www.ingen-tech.com
http://www.pulseoximetersdirect.com
Click to expand...

Bill,
Thanks for posting this info!
Mark
 
Oxygen Transfill Adaptor CGA540 CGA870

If you look on ebay, under:
Oxygen Transfill Adaptor CGA540 CGA870 Medical Aviation
the one with a pressure gauge is $65, I bought the cheaper one without a gauge, as both bottles have gauges on thier regulators.
It works great. I fill it at my son's shop, from his welding O2 bottle just after he gets in a fresh full one.
This adapter is short, and has a rigid joint to the large bottle, but a hose would add volume = wasted gas. I keep it in my oxygen tool bag of spare parts, hose, cannulas, masks etc. that I accumulated at incredible low prices. :D
Right now I have two independant systems: C medical bottles, precision 0-8LPM regulators and conserving cannulas. Our Cessna 182 won't go high enough to need a mask. :(
I am having trouble finding a good location for O2 in my RV-8 project. So far, no one has offered up a really good location. I want to be able to open the bottle in flight, which means having the post valve within reach, having a reach rod, or and expensive solonoid operated valve. I'm reluctant to mount it in the forward baggage for safety reasons.
 
My setup:

E-size bottle purchased used on eBay: $30 shipped.
CGA-870 0-4LPM mini regulator - eBay $25.95 shipped
2 Chad P-224 Oxymizer cannulas - eBay $50.00 shipped

CPC fittings, same ones MHOxygen sells, direct from manufacturer which is colder.com, without the big markup.

PMCD1602 1/8 Hose Barb Valved Panel Mount Coupling Body, $7.96ea
PMC2302 1/8 Hose Barb Non-Valved Elbow Coupling Insert $2.35/ea
PMC2202 1/8 Hose Barb Non-Valved In-Line Coupling Insert $1.00/ea
MCD1002 1/8 NPT Valved Coupling Body $10.51/ea (I'm replacing the barbed fitting on the regulator with this one)
 
Larry,

Yes, but I hope you check the weight and balance on your airplane. These things are fairly heavy, at least the ones I looked at a couple years ago. And they mostly require 110v power. For the price, you can fill a LOT of oxygen bottles.

greg
 
PORTABLE O2 SET UP

I'm not a pilot, but am an oxygen user who does many outdoor activities, sometimes at high elevations.

I have an idea that might be helpful, and also wonder if any of you have tried this.

Precision Medical makes makes a portable liquid unit (Easy Mate 6 + 6; Note, the is different from and Easy Mate 6). It can be used on pulse (O2 conservation mode where O2 is only released during inhalation) as well as the standard continuous lpm mode. The O2 connector on the Easy Mate 6 + 6 uses a nasal cannula with only tube, instead of two tubes.

I sometimes use the continuous mode. The Easy Mate 6 + 6 should provide approx 8 hours of continuous O2 set at 2 lpm. But, since it uses a single lumen cannula, I wonder if an oxygen conserving cannula (a reservoir cannula) can be used to make O2 last longer. One brand is Oximizer and I know I saw another on an aviation / sports websites that provide O2 (Cant think of website name).

When using an O2 conserving cannula with standard O2 tanks, your blood should be well saturated with a lower lpm setting, making the tank last longer. For instance, O2 sat using conserving cannula set at 1 lpm should result in the same or better O2 sat than when using a standard cannula set at 2 lpm.

Of course, you do need a separate liquid reservoir to fill these portable tanks. Operating pressure of these portable systems is very low, and I'd think much safer than O2 in standard cylinders.

Do any of you have experience with this? Can you shed some light on my idea?
 
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There are also some very small portable O2 concentrators that are approved for commercial airlines. The smallest do not have a continuous mode, but some do. I like the Inogen One G2, but it still requires power (2 batteries are available that should last 4 and 8 hours)
 
I just thought of another Portable liquid device that uses a single lumen nasal cannula. It does not have any pulse (O2 conserving settings); just continuous lpm.

A fill would normally last approx 8 hours at 2 lpm with standard cannula. Apparently an O2 conserving cannula allow you to use a lpm setting That'sapprox 1/2 -3/4 of normal required. This device has a max delivery of 6 lpm (the Companion 1000T extends to 15 lpm)

Any thoughts?
 
allypurp said:
I just thought of another Portable liquid device that uses a single lumen nasal cannula. It does not have any pulse (O2 conserving settings); just continuous lpm.

A fill would normally last approx 8 hours at 2 lpm with standard cannula. Apparently an O2 conserving cannula allow you to use a lpm setting That'sapprox 1/2 -3/4 of normal required. This device has a max delivery of 6 lpm (the Companion 1000T extends to 15 lpm)

Any thoughts?
Click to expand...

Got any ideas on where to fill it up with LO2? How about "on the road"?
 
You can get them filled at places that provide Home health care, durable medical equipment, and probably fancy pharmacies that supply the above.

I start by asking my local provider (they have many locations) or do a google search.

Just make sure your reservoir is compatible with the large filler tank owned by provider. I know most of the reservoirs I've had or looked at are compatible: Puritan Bennet (for helios and Marathon portable units), Caire (Companion and many other portable units), possibly Pulse Air?? I think everything I've researched is compatible with those brands. Just be sure to get a reservoir that will fit in your vehicle and that you can physically handle. They are very heavy, but the O2 seems to go a long way. Know that O2 will slowly evaporate from reservoirs AND portable units even when not in use....so fill up shortly before your flight.

Another portable unit I though of is made by Puritan Bennett and is called the Marathon H 850. It might be a good compromise as far as size and purpose. It has both continuous and pulse modes. But, it requires a double lumen cannula. I've used a regular single lumen cannula on a similar unit in the past. I've only found single lumen conserving cannulas. The marathon would need a double lumen if used in pulse mode. In continuous mode, you could occlude one of the 2 tubing connector sites on the portable unit. You could cut a short piece of any cannula, attach to one connector and tie it off. Or, maybe duct tape would work. Then a conserving cannula could be used on the 1 available connection to extend time O2 lasts in continuous mode.

I think the Marathon might be a good comprise if you want a unit that has pulse and continuous modes. It's easy to find, and to me, is a acceptable size and weight. It's 5.6 lbs full, will last for 22 hours on pulse mode set at 2, or 5 1/2 hours continuous at 2 lpm (it should last at least twice that long with a conserving cannula set at 1 lpm continuous). A BIG plus with the Marathon (and the Helios H300....smaller with pulse mode only) is that they can be positioned anywhere from upright to horizontally up to 90 degrees (I don't know if any others can be used other than in the upright position).

From what I can tell, the Precision Medical Easy Mate 6 + 6 (with 2 modes and single connection site) is brand new and might be harder to find. If you don't care about having pulse mode, the Caire Companion 1000 might work (Caire has all sorts of stuff).

Hope this helps. Please share any insights or thoughts any of you have.
 
allypurp said:
They are very heavy, but the O2 seems to go a long way. Know that O2 will slowly evaporate from reservoirs AND portable units even when not in use....so fill up shortly before your flight.
Click to expand...

See, these are problems - weight is actually pretty important in light airplanes, and most folks don't go fill their O2 just before a flight - we keep them filled in the hangar (or home) and take them when we think we need them. There is also a need to refill them on trips out west when you are flying at altitude - and that means you have to have reliable suppliers at airports.

Many military aircraft use LO2 systems, because most bases have the capability to maintain and fill them. But until you can get this service at most GA facilities, it really isn't practical. Sort of like trying to burn MOGAS exclusively - if you have it in your hangar, or your airport has a pump, and you only fly locally, it's great - but you just can't reliably find it on cross-countries, so you end up burning AVGAS on cross-countries.

Paul
 
The only way I can work this out when traveling is to have a reservoir in my vehicle (I just learned about the one you mentioned). The evaporation from reservoirs and portable units is a whole lot slower when the units or turned off. I have a 35L reservoir now (easily fits in many vehicles, but is heavy). It lasts for a number of weeks unused. It lasts a good 1-2 weeks if used off and on (maybe 8 hours per day). If you can find the specs on these, you can usually get an idea of how fast O2 evaporates while TURNED OFF.

Is the reservoir you mentioned a lot more expensive than the others (? name; the concentrator that converts gas to liquid and then stores it)? One beauty of the conventional reservoirs is that they don't require electricity (something I usually don't have when out camping and such.

The lightest two portable units I know of just have pulse mode (they might be fine for your use). They are the Puritan Bennett Helios (I think the newer version is Helios H300 and the Precision Medical Easy Mate. Both of those will last approx 8 hours (turned on) when set on pulse mode 2. They are already O2 conserving devices. Not sure if using a conserving cannula on the Easy Mate (which normally uses a single lumen cannula) would help extend how long the O2 lasts TURNED ON. The Helios weighs 3.4 lbs full; the Easy Mate is a bit heavier, I think by several ounces (? still under 4 lbs).

You can buy used ones refurbished online when they're available.
 
I wonder if the liquid O2 maker (? name) has a compatible fitting for filling some of the other portable devices. I've only seen one portable that goes with that (don't know if there are others).

If you know of any lighter and smaller portables than the two I mentioned in the last post, please let me know. For my use, I would want something that would last 6-8 hours with pulse mode set on 2.
 
Liquid oxygen requires extremely cold temperatures to stay liquid, thus the evaporation issue mentioned. I routinely deal with liquid nitrogen, which is very similar in character. I find it hard to believe that liquid oxygen will keep for any significant length of time without lots of insulation (i.e., vacuum bottle or similar) and even then a bottle of a reasonable size for an airplane will likely only remain cold for a couple days at most before it is completely evaporated away. Given the issues with obtaining LOX and keeping it cold, a compressed gas cylinder makes much more sense for a pilot.

I looked at the continuous oxygen generators and these were expensive and heavy (as well as eating space), and didn't seem to be particularly useful for an airplane like an RV given those constraints. And they will get less efficient at altitude.

My experience and opinion.

greg
 
You are right. any small portable liquid will be gone in a couple of days if not used.

Have you seen the Inogen One G2 portable concentrator? The newer ones run on AC, DC and batteries. Weight is approx 7.25lbs with an 8 hour battery, and 8.75 lbs with a 12 hour battery. It's about 10 1/2" X 9 1/2" X 4 ". That is probably still a bit heavy and big for your purpose (as I said, I'm not a pilot, but can appreciate the problems with having O2 for all sorts of situations.

I agree about the cylinders. They are the most reliable. and, you can buy very light cylinders these days. You can also get a good size home O2 concentrator that will refill smaller cylinders. Not sure, but I think it's made by Invacare.
 
airguy said:
Actually, you spend the equivalent of buying the system every 27 months - assuming you refill the bottles once a month. Hydrotesting the bottles can be done very easily and cheaply, I have several high pressure bottles tested per month for my air business at $22 per test. Metallic bottles only need to be tested every 5 years, and have an unlimited lifespan as long as they are undamaged and not exposed to excess heat. Carbon fiber or fiberglass wrapped bottles must be tested every 3 years and have a maximum 15-year life span. They are also more expensive, but less weight for the quantity of oxygen they can carry.

As far as filling them - and I'm not going to advocate for or against this practice, just use your own judgement - I know many pilots who have a pair of oxygen bottles from an oxy-acetylene torch setup with a transfill valve to top off their plane bottles. It reduces your oxygen costs to pennies per refill. Say what you want about the practice - but as an analytical chemist with a couple years of actual lab time working with it, I've personally run the tests to tell you that there is no appreciable difference between "medical", "aviation", and "industrial" grade oxygen supplied in the cylinders. There used to be, yes, but with todays modern air liquefaction plants there is no economic incentive for multiple grades of purity - all the oxygen comes from the same liquid oxygen supply at the liquefaction plant. The difference is in how much paperwork accompanies it to prove it's pedigree - just like experimental aircraft and engines. From an analytical purity viewpoint, you don't see a difference until you go to the expensive UHP (Ultra High Purity) gases used for Mass Spectrometry and some gas chromatographs.

And yes, once I have my bird flying, I will have onboard oxygen and I will roll my own and fill my own - but then again I've been working with high pressure gases for close to 20 years and I'm quite comfortable with them.
Click to expand...

There most definitely IS a different between Medical, Diving, Aviation, and Industrial Grade O2.

However its not necessarily in the gas.

There are two areas of difference. First, the moisture content. Medical oxygen has a much higher H2O content. Pure oxygen is not only toxic but can burn and dry out mucous membranes. Diving oxygen has less and aviation is the dryest. Moisture can freeze in the 1st stage of the regulator above freezing temps due to the temperature drop as the gas expands out of the tank (probably max 2,400 psi) to basically ambient. Having your O2 go offline due to ice buildup at high altitudes would be bad. You will not experience a thing, you will just quietly drift off. Remember! If you wake up and none of the instruments make sense to you, don't touch anything it will soon be over.

Second difference is the level of potential toxins and how the tanks are handled. Tanks for breathing gasses are evacuated before being filled. Non-breathing gases are just filled on top of what ever is in there. If you are renting a K bottle and cross filling with a whip or something this could be something to think about. If you own and control your own bottle, not an issue.

However, I would strongly caution anyone who plans on building their own O2 handling gear or doing their own fills. O2 is VERY, VERY dangerous! It is toxic, it can burn, it can explode with AMAZING results. Carbon steel will burn in an all O2 environment. The slightest, tiniest, most minute piece of debris like lint or a crumb of O ring inside your bottle can cause an explosion of immense devastation. Even filling a bottle too fast, or a vibration in the line as the gas flows over it can cause an explosion. Your skin, clothes, and hair will burn instantly in an O2 fire. Your clothes will be O2 saturated and will be impossible to put out. If you are doing your own fills, especially if you are getting a K bottle and doing fills with a whip or something, take a class, learn how to handle O2.

-Certified Gas Blender
 
walkman said:
There most definitely IS a different between Medical, Diving, Aviation, and Industrial Grade O2.

However its not necessarily in the gas.

There are two areas of difference. First, the moisture content. Medical oxygen has a much higher H2O content. Pure oxygen is not only toxic but can burn and dry out mucous membranes. Diving oxygen has less and aviation is the dryest. Moisture can freeze in the 1st stage of the regulator above freezing temps due to the temperature drop as the gas expands out of the tank (probably max 2,400 psi) to basically ambient. Having your O2 go offline due to ice buildup at high altitudes would be bad. You will not experience a thing, you will just quietly drift off. Remember! If you wake up and none of the instruments make sense to you, don't touch anything it will soon be over.

Second difference is the level of potential toxins and how the tanks are handled. Tanks for breathing gasses are evacuated before being filled. Non-breathing gases are just filled on top of what ever is in there. If you are renting a K bottle and cross filling with a whip or something this could be something to think about. If you own and control your own bottle, not an issue.

However, I would strongly caution anyone who plans on building their own O2 handling gear or doing their own fills. O2 is VERY, VERY dangerous! It is toxic, it can burn, it can explode with AMAZING results. Carbon steel will burn in an all O2 environment. The slightest, tiniest, most minute piece of debris like lint or a crumb of O ring inside your bottle can cause an explosion of immense devastation. Even filling a bottle too fast, or a vibration in the line as the gas flows over it can cause an explosion. Your skin, clothes, and hair will burn instantly in an O2 fire. Your clothes will be O2 saturated and will be impossible to put out. If you are doing your own fills, especially if you are getting a K bottle and doing fills with a whip or something, take a class, learn how to handle O2.

-Certified Gas Blender
Click to expand...

Not as many differences as you mention. Medical oxygen is "moisturized" at delivery to the patient to lower corrosion effects. It is delivered dry.

Actual specifications here...

http://www.c-f-c.com/specgas_products/oxygen.htm

Glider pilots have been using welding oxygen for many decades and fly 10s of thousands of feet higher than RVs...:) It has been proven in actual use.
 
Flying Scotsman said:
Divers don't use pure oxygen, AFAIK. It's just compressed air.
Click to expand...

For sport and recreational diving, that's true. For technical diving at greater depth they will use a synthetic mix of nitrogen, oxygen, and/or helium depending on how deep and how long.

walkman said:
There most definitely IS a different between Medical, Diving, Aviation, and Industrial Grade O2.

However its not necessarily in the gas.

There are two areas of difference. First, the moisture content. Medical oxygen has a much higher H2O content. Pure oxygen is not only toxic but can burn and dry out mucous membranes. Diving oxygen has less and aviation is the dryest. Moisture can freeze in the 1st stage of the regulator above freezing temps due to the temperature drop as the gas expands out of the tank (probably max 2,400 psi) to basically ambient. Having your O2 go offline due to ice buildup at high altitudes would be bad. You will not experience a thing, you will just quietly drift off. Remember! If you wake up and none of the instruments make sense to you, don't touch anything it will soon be over.

Second difference is the level of potential toxins and how the tanks are handled. Tanks for breathing gasses are evacuated before being filled. Non-breathing gases are just filled on top of what ever is in there. If you are renting a K bottle and cross filling with a whip or something this could be something to think about. If you own and control your own bottle, not an issue.

However, I would strongly caution anyone who plans on building their own O2 handling gear or doing their own fills. O2 is VERY, VERY dangerous! It is toxic, it can burn, it can explode with AMAZING results. Carbon steel will burn in an all O2 environment. The slightest, tiniest, most minute piece of debris like lint or a crumb of O ring inside your bottle can cause an explosion of immense devastation. Even filling a bottle too fast, or a vibration in the line as the gas flows over it can cause an explosion. Your skin, clothes, and hair will burn instantly in an O2 fire. Your clothes will be O2 saturated and will be impossible to put out. If you are doing your own fills, especially if you are getting a K bottle and doing fills with a whip or something, take a class, learn how to handle O2.

-Certified Gas Blender
Click to expand...

Uhmmm.... yeah... Ok.

As has been pointed out already - the moisture is added at the hospital (or wherever you are being administered oxygen) to keep from drying out your mucous membranes. The oxygen in the bottle is the same. Do you think the hospitals use magic regulators that would allow them to drop their oxygen pressures without freezing up? Actually it's worse than that - most hospitals store their oxygen as liquid - at cryogenic temperatures - any moisture would plug the transfer lines. There is no moisture present until it's added to the stream at the time it's administered to the patient.

You do have one good point about making sure your bottle is clean if you roll your own system, I'll give you that one. If you can't (or don't want to) evacuate your oxygen bottle before filling, then just fill it and dump it to atmosphere about 3 times - any non-oxygen gas inside will be well purged.

The rest of your statement about explosions and fire is about 2% truth and 98% fearmongering, and I absolutely abhor fearmongering. I've been working with compressed air and oxygen to 6000 psi for more than 20 years, and I actually understand the physics behind what I'm doing. If you were really a certified gas blender you would too, and you wouldn't make statements like you did. Oxygen is not toxic to humans or animals in any quantity at atmospheric pressure, period, end of story. It does not burn - it supports combustion. Filling a bottle too fast will cause it to heat up - not cause an explosion - as long as the bottle is clean (like it should be). Having debris in your bottle is a bad thing - but it will only be able to burn and cause problems if it's heated to it's combustion point - which you are not going to do without almost trying to. I've personally tried to induce an oxygen explosion in a bottle with flammable contents at pressures up to 14,000psi in one case - I was never able to get it to light off. If you do manage to light it off, the bottle still won't explode unless you've got enough material in there (not just a few crumbs) to create such a large amount of exhaust gases from combustion that you cause the bottle to rupture from the overpressure - and even then the bottle has a burst disk that will turn loose and vent the bottle before you can get to that point. The only documented cases I've ever seen of oxygen combusting with debris has been in small piping sections where lube oil or some other minor debris was present, and the line was pressurized from atmospheric pressure to around 2000psi in less than a second by quickly opening a valve to the high pressure source. That can indeed cause localized heating to a level high enough to "diesel" any debris present - but you are not going to be able to fill your TANK that fast, and this also requires the debris to be present in sufficient quantity in the first place.

Oxygen gets hot when compressed, as do most (not all) gases. If the compression creates heat faster than the walls of the container can absorb it, then temperature can rise to the point where a flash fire is POSSIBLE if there is debris present - but we are talking about going from one atmosphere to 150 atmospheres in a second or less - that's simply not going to happen when you fill a bottle, you simply can't move that much gas through those valves fast enough. It's still a bad idea to flash-fill any bottle - for a variety of reasons - but not for the ones you give.
 
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hendrik said:
Which gases don't? And why?
Click to expand...

Any gas with a negative Joule-Thompson coefficient - of which there are exactly three that can achieve that state at room temperature - hydrogen, helium, and neon.

If a gas is above it's inversion temperature, it will heat when compressed and cool when expanded. If the process is started with the gas below it's inversion temperature, it will cool when compressed and heat when expanded. At room temperature only hydrogen, helium and neon are below their inversion temperatures. As you get into the colder cyrogenic world, some other gases will reach their inversion temperature before freezing out, if the pressure is correct.
 
Ah! Thanks for the explanation. It triggered me to get the dust of my thermodynamics books and read again about real gases. I don't think I've ever thought about this implication of the "-2a" in the van-der-Waals equation, but it makes perfect sense now. :)

But I think you have your below and above inversion temperature mixed up.
 
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hendrik said:
But I think you have your below and above inversion temperature mixed up.
Click to expand...

You're correct, of course - I missed the polarity on the curve.

One of the interesting outcomes of this is that under the right conditions, a high-pressure hydrogen leak from ambient temperature can actually heat itself enough from expansion to self-ignite in air.

/THREAD DRIFT

We now return you to your regularly scheduled oxygen conversation...
 
airguy said:
For sport and recreational diving, that's true. For technical diving at greater depth they will use a synthetic mix of nitrogen, oxygen, and/or helium depending on how deep and how long.



Uhmmm.... yeah... Ok.

As has been pointed out already - the moisture is added at the hospital (or wherever you are being administered oxygen) to keep from drying out your mucous membranes. The oxygen in the bottle is the same. Do you think the hospitals use magic regulators that would allow them to drop their oxygen pressures without freezing up? Actually it's worse than that - most hospitals store their oxygen as liquid - at cryogenic temperatures - any moisture would plug the transfer lines. There is no moisture present until it's added to the stream at the time it's administered to the patient.

You do have one good point about making sure your bottle is clean if you roll your own system, I'll give you that one. If you can't (or don't want to) evacuate your oxygen bottle before filling, then just fill it and dump it to atmosphere about 3 times - any non-oxygen gas inside will be well purged.

The rest of your statement about explosions and fire is about 2% truth and 98% fearmongering, and I absolutely abhor fearmongering. I've been working with compressed air and oxygen to 6000 psi for more than 20 years, and I actually understand the physics behind what I'm doing. If you were really a certified gas blender you would too, and you wouldn't make statements like you did. Oxygen is not toxic to humans or animals in any quantity at atmospheric pressure, period, end of story. It does not burn - it supports combustion. Filling a bottle too fast will cause it to heat up - not cause an explosion - as long as the bottle is clean (like it should be). Having debris in your bottle is a bad thing - but it will only be able to burn and cause problems if it's heated to it's combustion point - which you are not going to do without almost trying to. I've personally tried to induce an oxygen explosion in a bottle with flammable contents at pressures up to 14,000psi in one case - I was never able to get it to light off. If you do manage to light it off, the bottle still won't explode unless you've got enough material in there (not just a few crumbs) to create such a large amount of exhaust gases from combustion that you cause the bottle to rupture from the overpressure - and even then the bottle has a burst disk that will turn loose and vent the bottle before you can get to that point. The only documented cases I've ever seen of oxygen combusting with debris has been in small piping sections where lube oil or some other minor debris was present, and the line was pressurized from atmospheric pressure to around 2000psi in less than a second by quickly opening a valve to the high pressure source. That can indeed cause localized heating to a level high enough to "diesel" any debris present - but you are not going to be able to fill your TANK that fast, and this also requires the debris to be present in sufficient quantity in the first place.

Oxygen gets hot when compressed, as do most (not all) gases. If the compression creates heat faster than the walls of the container can absorb it, then temperature can rise to the point where a flash fire is POSSIBLE if there is debris present - but we are talking about going from one atmosphere to 150 atmospheres in a second or less - that's simply not going to happen when you fill a bottle, you simply can't move that much gas through those valves fast enough. It's still a bad idea to flash-fill any bottle - for a variety of reasons - but not for the ones you give.
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Oxygen is most definitely toxic to humans. Although not at the pressures and exposures that as pilots we are likely to see. However it is definitely something I have to calculate when doing technical decompression diving.

I never said it burns, I said it helps other things burn - VERY rapidly. It can can cause serious fires and explosions when not handled correctly and worse, those fires are extremely difficult to put out.

Filling a bottle makes it heat up yes. But there are other problems with filling too fast, for example vibrations in the system, in particular with valve parts in an improperly designed system can cause serious issues. If the system is designed properly the issues are much lower, which was my point. Design it properly, which requires learning what the issues are.

Oil is a real problem. Which requires the right type of compressor and filters etc to prevent any oil getting into the pressurized side of an oxygen handling system.

I agree, opening a valve rapidly is one of the worst things you can do.

I may be incorrect about the H2O content, I was not thinking about the supply systems at hospitals, but more the portable systems you see emphysema patients etc with.

I have personally seen the aftermath of an explosion and resulting fire caused by simply putting a contaminated pressure gauge (bourdon tube style) on an oxygen bottle. It involved a significant amount of roasted human.

My points were simply its not something to whip up in your garage without understanding how to do it and how to handle it. I personally do it in my garage (well, storage unit) all the time. Its just worth understanding what you are doing and the pitfalls of what can go wrong.

Oh, and most technical diving, unless its Navy or NOAA or similar, does not use a "synthetic mix". Its simply partial pressure blending of O2, followed by He, followed by air.
 
walkman said:
Oxygen is most definitely toxic to humans. Although not at the pressures and exposures that as pilots we are likely to see. However it is definitely something I have to calculate when doing technical decompression diving.
Click to expand...

Yup - pretty sure I pointed that out when I said "at atmospheric pressure". Oxygen toxicity is well documented at technical diving depths, but that doesn't apply in the situation you were talking about in your original message.



walkman said:
I never said it burns, I said it helps other things burn - VERY rapidly.
Click to expand...

Gonna have to disagree with you there - and I'll do it with your own words from your original post - "
walkman said:
It is toxic, it can burn, it can explode with AMAZING results.
Click to expand...
"

walkman said:
Filling a bottle makes it heat up yes. But there are other problems with filling too fast, for example vibrations in the system, in particular with valve parts in an improperly designed system can cause serious issues. If the system is designed properly the issues are much lower, which was my point. Design it properly, which requires learning what the issues are.

Oil is a real problem. Which requires the right type of compressor and filters etc to prevent any oil getting into the pressurized side of an oxygen handling system.

I agree, opening a valve rapidly is one of the worst things you can do.

My points were simply its not something to whip up in your garage without understanding how to do it and how to handle it. I personally do it in my garage (well, storage unit) all the time. Its just worth understanding what you are doing and the pitfalls of what can go wrong.
Click to expand...

We're on the same side here from the standpoint of how to do it correctly - but let's stick with physics instead of fear when we're discussing it, mmmkay?
 
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ok you got me on the "it burns". fingers engaged before brain was. my mistake.

regarding toxicity, have to go back to my texts, but I think there is a toxicity issue that is due strictly to exposure length that theoretically could be exceeded at 1 ATM. However it would have to be one bloody long flight. :)
 
ball type flowmeter

As I'm getting near to completion i have revisited this thread as I want to have O2 available.

I've perused this thread fairly well and am about to order some parts to roll my own. Almost all of the regulators that I've run across are actually flowmeter/regulators yet I've seen several threads that suggest they used a ball type flowmeter in addition. Is this a necessary addition to these systems? I'm also assuming that a 8L regulator is big enough, correct?

I'm planning to use the quick connects that have been mentioned and a D size tank.

Thanks
 
An 8L regulator will be more than sufficient. Actually better to have a smaller regulator than a larger one. I typically use 0.5LPM at most, even at 18K. The ball flowmeters generally are labeled in altitude (but take that with a grain of salt and use a pulse oximeter) and can give you much finer control on the flow, resulting in conservation of oxygen.

Greg
 
Paul,

In addition to being able to set the flow and conserve O2 (as Greg said), one nice side-benefit (IMHO) of the ball flowmeters is that it gives you a visual indication that O2 is actually flowing (no pinched or disconnected lines upstream, no empty bottle, etc). Just an additional "warm-fuzzy" provider. I stole and morphed Greg's design, and put my flowmeters where they could be easily reached and peeked at from time to time, but I also use a pulse-ox to spot check when I'm on O2.

The flowmeters also give you another way to tell (by the "ball drop") that you've evacuated & depressurized the lines (breathed 'em empty) after you've shut off the regulator during descent or after landing. Regulator pressure at zero does that too, but its another possible use of the flowmeter.

I've also used the ball drop to squeeze the last of the O2 out (to stay a bit higher for winds and rides), then descend when the bottle went "winchester" (empty). (I'd only do that when descending is an easy option though...not to clear terrain or weather...FWIW).

Just some thoughts...have fun rolling a system...its a fun project that you'll get lots of use out of!

Cheers,
Bob
 
Thanks alot guys. I think I'll go with the flowmeters then. Makes more sense. I like warm and fuzzy's about that kind of stuff. I sure liked the pictures, Bob, of your setup.

One more question though. When you turn the regulator on do you just open the flow up on it and use the ball flowmeter to set the actual flow?

I think it will be one more of those things to do while I'm still in the shop at home.

Thanks
 
Paul,

Probably lots of possible techniques in setting the O2 flow. Greg mentoned he typically uses 0.5 on the regulator, and I find I use 1.0-2.0 (alone or 2-up, respectively). I leave the flowmeter in its last position between flights, versus opening and closing that valve...just dont want to keep working that little needle valve back and forth (not sure its a big deal, just my technique), and that way it's sort of pre-set for the next time.

I will bump it up to 2.0 just for me when I'm up above 15K or so, especially when its hot and the DA is higher than IA. I then fine-tune it with the flowmeter by placing the ball about 1K above my current altitude. I use DA, just to be on the safe side...though there has been good debate on whether its DA or IA, not trying to re-open that...I just play it conservative. I have noted that at 17.5 IA on a hot day (thus DAs over 19K) even with the ball at the top of the flowmeter, my pulse-ox indications start to drop. Next time I do that I'll try to open up the regulator flow further (flowmeter is already at the top, but we'll see if that keeps the sat levels higher). There are likely many factors in that equation though...fatigue, water intake, food intake, recent exercise, etc.

Its a great add to the capabilities of the airplane though, that's for sure!

Cheers,
Bob
 
Thanks Bob, that's pretty much what I thought. Seems as though the flowmeter in the regulator is just "there" and you wouldn't want it to "limit" the flow.

I'm going to put together an order and get it started. I know from past experience that having the O2 on, even above 6 or 7000 feet, makes one feel alot better at the end of a long cross country and that's what I intend to use it for.

Thanks again
 
Something Different

After having gotten most all of these parts together, my welding supplier, who also supplies most of the hospitals around here showed me a "D" size cylinder with a valve regulator combination. Here's the link

http://www.sherwoodvalve.com/assets/base/doc/OxyGen/OxyGen1_Valve_Regulator_Applications.pdf

It seems to me that this might be useful as well as any other method. I don't know the actual cost as it's a freebee for me. Is there any reason this wouldn't work as well?
 
One possible downside is not being able to read the pressure gauge easily (depends on how you mount the cylinder, though). I presume it is easily refilled using standard fittings so that's not an issue. Seems a good deal to me.

Greg
 
Strange fitting

I recently completed a lengthy trip and could not find an airport to refill my new Aerox bottle. At Columbia Gorge airport KDLS a line lady brought me to a refilling station but fittings were different. Very close but different. How do you guys top your bottles? Any advice on this particular fitting? I browsed the thread and could not find discussion about this attachment.


aeroxfitting.jpg



I do have access to bulk medical oxygen and I've read about its properties.
 
Roll your own 02?

Just trying to sort through all the posts so i can figure out what and where to buy the parts to make a good 2 person system.

Anyone feel free to chime in.

2 oxysaver cannulas (can source lots of places) CHAD p224 seem to be ideal.
A decent size medical bottle and the gear to refill from my 02 welding tanks can be grabbed locally without trouble. Aluminum size d seems standard.

That seems pretty simple. What i dont have a clue about is what is a simple, easy to use and accurate metering, splitting valve set up to put on the tank, split and regulate for two people depending on alt?
Seems a regulator with ability to control down to .25lpm is ideal, and then a ball type flow control to SHOW flow, with a y splitter that can be isolated to shut off one line if no passenger.

Any links to what you have used, had good success with or would do differently, fits to refill easily from big tanks etc would be great.

I just cant see spending $500, but am not clear how best to set this up to work as needed. Thanks.
 
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Filling

I did have trouble finding a place to fill it up! The FBO wanted $75 and did not have the right size adapter anyway... The Welder shops ALL said no-way, we cant touch a medical or an aviation bottle (the FDA will get us) and the medical equipment stores all said I needed a prescription for O2 from a doctor (it a drug you know;) I ended up finding an adapter (which I should have bought from DeltaO2 in the first place) and going back to the FBO to fill it... Im still not sure why the Welder suplly shops here in KY are so gun shy.:confused:
 
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