flashback arrestors and check valve question
 

Hello!

I am in the process of upgrading from a HH to a dual fuel. I could use some advice on flashback arrestors and check valves. I purchased a hose kit with hoses, flashback arrestors, check valves and regulators. I understand the need for flashback arrestors, but what is the purpose of check valves? Do you use both on propane line? I purchased an oxycon, I understand you do not use the flashback arrestors on that, but what about check valve? Does it not restrict the flow of oxygen to the torch? Seems like that would be an issue on a oxycon as the pressure from that is not that strong to begin with....
Thanks for any info!

What kind of check valves do you have? Are they plastic or metal?

Just a little clarity here.... Two things, there is no such thing as a "duel fuel" torch... Don't know where phrase came from but its a bad description for a fuel/oxidizer torch...

And by nature for the most part, a flashback arrestor is a check valve by nature unless it is a "fire (flame) stop" used in very low pressure (1/3 psi) natural gas or propane supply in lieu of a flashback arrestor...

The exception to the above is when you have two or more concentrators and you use a check valve to isolate each one from back pressure from the other ...

Dale

the check valves are metal...

Dale, so if I have a flashback arrestor next to my regulator on propane hose I do not need the check valve next to my torch?

.. and I don't need either for my oxycon line?

If you have flashback arrestors, you do not need check valves. Flashback arrestors are better placed close to the torch than at the regulators/tanks. A lot of times, flashbacks go up the oxygen side. A flashback arrestor placed near your torch will save your line, in addition to keeping your machine from being burned. The downside is that they restrict flow. A flame stop might be a better option for the concentrator side.

Kimberly, is it not advisable to run the oxycon without either? I have the flame stop (check valve? ) on the oxycon line now too and it seems to restrict the oxy a lot...
Thanks!
Anna