SpudFiles

If necessary I can go into the details of why I need help constructing a safe oxygen metering system, but for times sake not now.

Basically the dangers of oxygen in incompatible systems is highly emphasized in my Google searches, but the specifics of safe systems is irritatingly elusive. Please correct if I am wrong, but from what I gather the lower the pressure of the O2, the less volatile. From that and no need for higher pressures I figure a operating pressure in the neighborhood of 20 PSI.

I'm outfitted with a decent hobbyists machine shop, so I'll be able to construct a 3-way valve, and check valves myself but hopefully you guys can help me when it comes to selecting compatible materials. Obviously metals, and O-rings.

I've brought about the issue several times in private conversations and I intend to implement these points into the system:

*Bathing the system in both denatured alcohol and acetone to remove any oily type residue
*Obviously not use any oils or lubricants
*There's more but this headache of mine is killing any productive recollection

Thanks and input would be greatly appreciated.

Stick to stainless, a corrosion resistant grade, such as 316. Burning and such of foreign materials won't be a problem unless its glaringly obvious. Cutting liquids (if used) during the machining will be the main problem. I say just don't use them, and take it slow. I have read somewhere that all the parts are subject to a burn, much like a combustion cannon. This is supposed to get rid of alot of problems. Normal O-rings should work, but teflon or viton would be a upgrade.

A UV light can be used to check the parts.

do not build a 3 way valve.. buy it - it's better to pay that 20 $ and get a product that works flawlessly... and before you do so ask if it can be used with O2

Don't use materials that will corrode or rust- stainless steel is a good method. Use the highest quality rings you can get as oxygen is no friend of rubber.

Okay, common sense approach.

Look at what's being used to handle oxygen at around 20psi.

Say for example,..an oxy/acetylene torch rig.

The regulators are brass, the torch is brass, the hoses ? The only reference I could find said that they were neoprene covered.

A look here;

http://www.hitechseals.com/chemicalcompatibility.asp

Turns up that neoprene is satisfactory for cold O2. As is teflon, but neoprene is readily available everywhere.

Getting things "oxygen clean" may not be as difficult as some might think.

http://www.m-y.ca/med/docs/Oxygen-Clean ... eedure.pdf

Check out the gas systems used to deliver medical O2 and you should be golden. Without lots of studying, my guess would be valves using silicone based lubricants, not petroleum, and gauges approved for O2 usage.

If you're looking for specific parts; look at mcmaster carr. Their products will note if they have suitability for oxygen or whatever application. They also supply gauges for very low pressures-high accuracy. What's it for?

Not all oils react with O2.
There are a lot of lubricants which are safe to use.

ininickname:
Those parts will not only have an oxygen rating, but also be extra expensive.

Call a welding supplier like AGA or who ever is in your local, they are a wealth of information but don't mention launchers. It's not so mush the reaction as the action. Oil is a pure fuel especially under pressure and oxygen feeds it. If you use acetylene with it don't use copper.

RalphD is correct; never use acetylene with copper. It forms an extremely reactive compound (seems to be a trend with acetylene) that is highly unstable and extremely explosive. It usually only occurs when acetylene is bubble through copper sulfate, but don't take my word on that. It's not something you want to tempt.

Psycix: as things like this usually are expensive, ordering from mcmaster wont help will it? There's a price you'll pay

By the way, go look at the copper tube handbook and have a look at medical grade copper for oxygen delivery as long as you're not using acetylene.

Yeah, but with a bit of cleanup and a pack of common sense, I am sure you can specific non-oxygen rated parts with oxygen. Thats what we are spudders for: use things in the way they are not meant to.
And it saves a lot of money.

Gippeto suggested the best approach, use the regulator etc. from an oxy welding torch setup. For an oxy source you can just use the small O2 cylinders that are the same size as Bernzomatic propane bottles.

It'll not only be the cheapest but also the safest. Yes, you can probably do it cheaper (and less safe, so "cheap" isn't true) but don't.

If you use the welding setup then you'll have the correct fittings and it will be more difficult to accidently plumb the wrong thing to the wrong place. Oxygen supply parts have a different thread than what is used for fuels. IIRC, for an oxy tank the fittings are reversed, so you can't connect the fuel line to the regulator or the wrong regulator to the tank.

starman wrote:Check out the gas systems used to deliver medical O2 and you should be golden. Without lots of studying, my guess would be valves using silicone based lubricants, not petroleum, and gauges approved for O2 usage.

Medical instruments dealing with 02 use plastics to stay within county fire code. Sounds weird I know but even as far back as 1983/1984 when I was in the hospital that was the way it was. Looked weak to me.