Wanted O2 bottle

On Wednesday, July 17, 2019 at 2:58:01 PM UTC-7, Geoff Minors wrote:
Wanted O2 Cylinder about 22" long total X 5" Diameter.

Your best bet is to choose a standard size medical cylinder, then have it fitted with a CGA540 valve to adapt to standard aircraft oxygen fittings. Most of the places that sell medical cylinders can do that for you.

Standard size chart:

https://www.tri-medinc.com/page12.htm#cyl-spec

Your best bet is to choose a standard size medical cylinder, then have it fitted with a CGA540 valve to adapt to standard aircraft oxygen fittings. Most of the places that sell medical cylinders can do that for you.

Wrong!

Medical cylinders, even though they are standard sizes, are invariably more expensive due to the influence of the legions of lawyers feeding off the health care system. (Rant off)

Medical cylinders are usually supplied with the "Puritan-Bennett" post type outlet valve which only connects to the same type (CGA-870) fill apparatus. All US industrial and aviation cylinders use the CGA-540 outlet. This includes welding applications.

Buying a "medical" cylinder with a CGA-870 fill system and then changing it to a CGA-540 valve and gauge will probably double the price of just buying the right cylinder and valve from Mountain High E & S.

https://www.mhoxygen.com/product/aluminum-cylinders/

The cylinder you want is probably either the AL-415 or AL-647. the 415 is 4.375 in diameter, the 647 is 5.3 inches. Length with valve is less than 22 inches. Don't forget to add the length of the regulator when planning for your installation.

And if you decide on a medical cylinder and CGA-870 fill system, don't be surprised when the airport won't fill it for you, and neither will a medical facility unless you have a prescription from a Doctor.

I have been selling and servicing Aviation Oxygen systems for hang glider pilots and sailplane pilots since 1991.

And, NO, there is absolutely no difference in medical, welding and aviation oxygen, except for the price, which is determined by the amount of paperwork, record keeping and liability associated with the intended application. (See above Rant)

Actually markm you are incorrect. It is about 1/2 to 1/3 the cost to purchase oxygen bottles from a medical or ems supplier versus an aviation source.. You can special order them with straight through or 90 degree cga 540 valves for a few dollars extra. The origional poster is looking for a D or Jumbo D bottle more than likely. Should cost about $100 USD from an EMS source.

Tim- Can you provide a link to the source you describe? I have never found a medical supplier that charges the prices you quote, and would like to have an option for customers who may require cylinders. Thanks.

Correction- I can find plenty of suppliers as described, but have not found any that offer the CGA-540 outlet with gauge. Only the CGA-870 post type.

http://www.cramerdeckermedical.com/c...?category_id=2

Thanks for the link. Note that the (optional) brass Sherwood CGA 540 valves do NOT have a pressure gauge and are rather bulky compared to the valve/gauge combination offered with the MH cylinders. But the price is definitely attractive.

On Thursday, July 18, 2019 at 5:20:57 AM UTC-7, wrote:
http://www.cramerdeckermedical.com/c...?category_id=2

I bought a tank from Cramer Decker for my PIK 20D in 2017. The valve supplied does not match the fine fit and finish of the Mt. High units, but still workable. However, the brand-new tank that I received had only two years left before the tank needed hydro tested earlier this year.

On Wednesday, July 17, 2019 at 7:45:58 PM UTC-7, wrote:
...Wrong!

.... Wow, you sure schooled me on penny pinching.

On Wednesday, July 17, 2019 at 7:45:58 PM UTC-7, wrote:
Wrong!

Medical cylinders, even though they are standard sizes, are invariably more expensive due to the influence of the legions of lawyers feeding off the health care system. (Rant off)

To expand on my earlier reply:

That may have been true back in the day, but for a variety of reasons medical cylinders have become very common, and consequently relatively inexpensive. Supply and demand and all that. I pretty regularly get such cylinders at yard sales for like $10 each, and they often come with electronic regulators similar in function to EDS. Sure, the medical posts and valves are an issue. But even with a valve change and hydro testing I come out way ahead of aircraft supply rates.

The usual problem is that the most common CGA540 valves are NPT pipe thread, while medical cylinders usually have a straight thread neck with a recess for an O-ring. But straight-thread CGA540 valves are available on the internet if you shop around. Make sure that the valve comes with an O-ring, or at least get the special O-ring from the supplier. The ones I've seen are some special white elastomer, and you probably shouldn't use a standard rubber or buna-n O-ring.

When you buy a medical cylinder without a valve, or with a valve change at the distributor, the cylinder will probably arrive empty--that is, filled with ambient air of unknown humidity. To make sure the cylinder is completely dry inside I will usually evacuate it with my vacuum pump and then do an initial fill from my welding oxygen bottle.

--Bob K.