Q. backflash arrester and hydrogen

I didnt even know there is such a thing as an oxygen flashback arrester. Sice oxygen isnt flammable. Henning

Sice oxygen isnt flammable.

Good thing I asked then. ;-)

Really???...Never heard of it? We have them on all of our hand held torches...you buy them in a set...1 acetylene/1oxygen

correct...oxygen isn't flammable...it's worse...it's an accelerant!!!! If the flame is already there, The oxygen is going to amplify it..you should always use arresters on torches.

As far as which to use, it depends on which threads you are using...left hand or right hand

Sice oxygen isnt flammable.

oxygen isnt flammable.

Yup. If there is a flashback thru the torch, you want to stop the flame on both lines because the oxy line will burn happily, fed by the pure oxygen inside.

For hydrogen you might need to do a bit of investigtion- it is squirly. You may need special devices to handle it. The arrestor is basicly screening in the line to cool the flame front enough it won't pass the arrestor, and hydrogen burns weird.

I would be much more concerned with line check valves than just the arrestor. Real important with acet, as the oxygen pressure is often high enough at the torch that if it feeds back into the acet line, the acet can self-detonate.

oxygen isnt flammable.

Thinking about this a little bit: my understanding is that you get flashback when then the acetylene hose pressure is less than the back pressure of the torch and oxygen can flow _back_ into the acetylene hose. The same thing can happen with the oxygen hose. My opinion based on very little experience.

Bob

Sice oxygen isnt flammable.

Sounds logical. I stand corrected. I even mada a check in a catalog and they had oxy and acetylen arresters. No mention of hydrogen. I would assume hydregen as a welding gas is quite rare. One lab I worked at once used laughing gas for some flames. Happy welding! Henning

Last time I worked with hydrogen (cryo liquid), we had explosion proof light switches and everything. It cost a _serious_ amount of money to equip the lab to work with it.

-- Smert' spamionam

But, just as acetylene wont burn w/ some oxygen (or other oxidizer) in it, if some fuel gas gets into the oxygen... (or am I thinking of check valves?

Sice oxygen isnt flammable.

Would not the fuel gas have a left hand thread? This would preclude using the O2 arrester.