OK, so I retrofitted a factory Oxygen system
into my B55 HERE and have found it to be a great
improvement in my O2 Saturation at my usual cruise altitudes of 10,000' to
13,000' and at night. It got me from the low 80's into the low 90's with a very
nice oxysaver cannula
for optimizing my on-board oxygen supply.
Still not convinced about the benefits of O2 in
the cockpit - Read about and listen to this chilling hypoxic
pilot audio conversation with ATC
HERE
Having price checked a few FBOs on the road
for oxygen bottle top offs and/or fills, I was shocked at what I was quoted for
this service. In most cases $65 or MORE!
This CSOB was
not about to fork over the equivalent of nearly an hours worth of 100LL for O2.
I had heard of many oxygen fill stations folks
had installed in their hangars and set out to research how to safely accomplish
this to do my own bottle fills in a cost effective manner.
WARNING
High Pressure
gasses are DANGEROUS! Do not attempt to build or operate high pressure gas or
oxygen systems without proper training. If in any doubt, consult a high pressure
gas professional or your A&P/IA who works with high pressure gasses on a regular
basis for guidance.
OR
Offer to pay for
the components and the system and let your A&P/IA build it and work out a
mutually acceptable compensation to service your system.
Check out the
below video for the results of incorrect oxygen cylinder handling
With the above warning as a backdrop, here is
a narrative on how I constructed my system.
I secured an account with a local welding
supply place for two full size tanks of Oxygen for about $20 each and a
$12/month cylinder rental charge. Understandably, there are different schools of
thought as to Welding O2 and ABO (Aviator Breathing Oxygen). Here is a quote
from Mountain High's
Technical Information Manual:
Contrary to a common and published myth, there are no
different grades of oxygen being produced or contained in cylinders maintained
under DOT regulations. By the very nature of the state-of-the-art process in
which oxygen is produced, it will be better than 99.99% pure.
In other words, it all originally comes from the same spout
no matter what the purpose. In addition, oxygen for medical use does not have
any more moisture than oxygen for any other purposes, nor is it added.
Furthermore, because of the chemical nature of oxygen it must be as pure and dry
as possible if stored under pressure or else the cylinder and equipment may be
damaged, or worse, personal injury or death may occur.
Therefore, a hygiene protocol is necessary in order to
prevent oxygen from being contaminated or to help keep contaminated oxygen from
being used. This, perhaps, is why many believe there are different grades of
oxygen.
For me, I'm satisfied that the many folks I've
spoken to and the above source, that I can successfully use Welding O2 for my aviation needs
without issues. I have learned that in some states if you ask for Medical O2 you will need to
present an Rx or some such thing.
Each tank has about 250 cubic feet of O2 in it
and is filled to about 2,200 psi. I hung a tag with a number on each tank "#1"
and "#2". I start with tank #1 and use that until I can no longer get 1,850psi
from it. Then I close Tank #1 and open the valve on Tank #2 and top off my
bottle.
My original plan was that when bottle #2 gets to 1,850psi, bottle #1 is going back
for exchange and bottle #2 will become bottle #1 and the freshly filled bottle
becomes bottle #2. Beech Lister Mike T. gave me some thoughts on optimizing my
oxygen cascade so I'm going to experiment with Mike T.'s thoughts below.
Here are some CSOB oxygen filling thoughts
from Mike T., an experienced Baron and Bonanza owner who refills his own oxygen
bottles:
You'll waste much less oxygen if you use both supply tanks
each time you refill your aircraft's tank. (Except when both supply tanks are
nearly full.) The idea it to first draw on your lower-pressure tank until its
pressure equals that of the tank in your aircraft and then switching to the
higher-pressure tank to top off the aircraft tank.
Again, this procedure is used for each refill. If your
aircraft's tank is nearly empty, you'll be able to get a lot of O2 from even a
partially filled supply tank. This will of course mean less is drawn from the
higher-pressure tank. This is the primary reason to connect the supply tanks in
a cascade. It makes drawing from several tanks during one refill much easier;
fewer connections to make; just turn the handles on the valves.
Also, the economics of filling one's own tanks depends on the
refill/exchange policy of the gas supplier. Some air shops charge a flat rate to
exchange cylinders regardless of how much gas remains in the customer's tank.
Others -- particularly those that are willing to refill a customer-owned tank,
rather than exchange it -- charge only for the gas it takes to top it off, pee
vee equals en are tee, etc. Any card-carrying CSOB will check with several local
suppliers before choosing one.
Finally, depending on your itinerary, it's frequently OK to
only partially fill your aircraft tank. You only need enough O2 for the upcoming
flight. Partial refills will help you get more gas from your supply tanks as
they're depleted.
Great thoughts Mike!
I got a 2-bottle oxygen cart off eBay for
about $69 including shipping. It looks fine for my light duty needs in my hangar
and has restraining chains and sits the bottles on a platform that rests with
the 12" wheels off the ground. It was shipped UPS and was a simple nut and bolt
assembly.
There are much more expensive and industrial strength
carts out there but I did not think I needed that kind of commercial durability.
GTS-Welco has the above cart
HERE for $89
I sourced a lot of the fittings and high
pressure oxygen "whips" from
Applied Home Healthcare
in Westlake, OH 888-327-7301.
They had most of what I needed and were CSOB priced from what I could research.
For bottle connections I used the CGA540 fittings. Here is the "T"
(aka Western Enterprises PN: T62) and pigtail whips
I purchased:
The whips are provided with 1/4"
NPT female ends and cleaned, capped and packaged for Oxygen service. I used a
1/4" NPT
Male-to-Male adapter to put two of them together.
Here is my parts list:
(1) 1109-1010 CGA540 "T"
(3) 1109-9914 CGA540 Nut
(3) 1109-9916 CGA540 Nipple
2.5" Length
(3) 1110-0536 Teflon Braided
Pigtail 36" (One of these could have been 24")
(1) Two Cylinder Tank Cart
w/Restraining Chains and >10" Wheels
I used three (3) of these CGA540 nuts and three (3) nipples
I thought getting a CGA540 wrench for ~$13 for my
filling station was a good idea for when I have to switch tanks. The wrench can
be conveniently placed in the cylinder cart tray as well as the wrench for
attaching my filling adapter 11/16"
Here is the 2.5" high pressure gauge I
selected @ about $15. It has a 1/4" NPT Male fitting and was placed into a 1/4"
NPT Female "T" that I sourced locally
I think one of the most important pieces of my
fill system is the needle valve. This allows me to control the rate of the fill
so that the little bottle is not filled too quickly. My research has determined
quite a number of warnings regarding too fast a fill rate which will heat the
bottle being filled. The reading I have done suggests that if you can
comfortably rest your hand on the bottle things are good.
My friend and Bonanza owner, Bo H. is an avid
scuba man and he had a needle valve specifically for this purpose. It is Parker
PN: N200B with 1/8" NPT Female Ends. It has a 3GPM flow rate, however, I opened
the valve just to the beginning of flow and that was a good rate for me. I used locally
sourced brass adapters to attach this to the 1/4" NPT high pressure whip and the
Scott adapter fitting.
Here is a 1/4" NPT Needle Valve, the
N400B that could integrate nicely into your 1/4" NPT high pressure whips
with a 5GPM flow rate. For additional safety I have decided I'm going to add the
N400B to my system just downstream of the pressure gauge to protect the flow
rate in the long section of whips.
Click
HERE for a link to all the Parker N-Series Needle Valve Specs
HERE is an
Auction for a new
N200B at $15
from seller: clevelandsupply
The other piece of the fill system is the
adapter to the Beech factory fill port which is a "Scott" fitting. This piece
pictured at the left end of the photo below, was sourced from Aerox
HERE
My Oxygen Fill System in Use
Check out how Peter H., an aviator in the UK,
solved his O2 filling needs:
My buddy Bo H., is an O2 system and Mixed gas
Blender Instructor trainer, for TDI
www.tdisdi.com and NAUI
www.naui.com and here are some of his watch outs:
Cleaning is imperative, "Crystal" simple green absent of the dye and perfume or
simple DAWN detergent is what the NAVY uses now. Clean till water no longer "
beads" or under a "black light' after 10 minutes no petroleum florescence.
This means- don't check your oil then open a tank.
Big pressure increases - filling to a closed
Scott pack valve or a sudden increase in pressure can have disastrous results
The proper O2 compatible Teflon tape is important too. Source this from your
welding supply or industrial supply house.
ANY PETROLEUM PRODUCT - grease gas even cigarette tar, ignites very easily in
the presense of pure oxygen - and
starts a chain of more stuff burning till the O2 is gone. Possibly creating a
3,500F, 8 foot fireball.
High Pressure
gasses are DANGEROUS! Do not attempt to build or operate high pressure gas or
oxygen systems without proper training. If in any doubt, consult a high pressure
gas professional or your A&P/IA who works with high pressure gasses on a regular
basis for guidance.
OR
Offer to pay for
the components and the system and let your A&P/IA build it and work out a
mutually acceptable compensation to service your system.
Check out the
below video for the results of incorrect oxygen cylinder handling
Aviation Oxygen Bottle Filling System
This CSOB was
not about to fork over the equivalent of nearly an hours worth of 100LL for O2.
Auction for a new
N200B at $15
from seller: clevelandsupply
