Cutting Torch Question

Where do I put the backflow preventer on my torch set? At the regulator end
of the hose or at the torch end?
Thanks
Rick
Reply to
Tod Engine Foundation
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Mine came with the backflow preventers at the torch. Gary Brady Austin, TX
Reply to
Gary Brady
I would put them at the regulator. If a hose caught on fire, and the preventers are out on the torch, there's nothing to keep it from going all the way back to the tank. Think about it.
Steve
Reply to
SteveB
My new Victor torch set came with the backflow preventers already mounted on the torch.
A Google search located an Oregon government safety site that said the backflow preventers must be installed at the torch.
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interps/2001/flashback31.pdf
This Oregon government site says the same thing, on page 12.
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pdf/rules/division_4/div4q.pdf
The California site below says they can be located in either place, but the document is refering to a system in which acetylene is piped around the shop, not where bottles are used, which I assume is your case.
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pages167-168.pdf
Based on my review, I believe that mounting the backflow preventers at the torch is standard industry practice, unless someone can produce an official document that says otherwise. Obviously you could buy an extra set and install them at both ends, but that is probably overkill, given that backflow preventers were not even standard practice until relatively recently.
My philosophy is to follow standard industry practice, I generally figure that standard industry practice is reasonably safe. Personal opinions are all over the map, you can find someone to support any position, including that the earth is flat. Industry practice is usually more of a consensus of experts, a safer bet.
Richard
Tod Eng> Where do I put the backflow preventer on my torch set? At the regulator end
Reply to
Richard Ferguson
They should be at the torch end. Backflow preventers are not fire suppression arresters. They prevent the higher pressure oxygen gas from flowing into the acetylene hose should the torch tip become fouled or blocked. Mostly when your torch is set up for cutting. If the oxygen gets into the acetylene hose or regulator then fire is the least of your worries. BOOM BOOM time.
Same reason you should also de-pressurize your hoses when your done for the day. Acetylene can migrate from the acetylene hose into the oxygen hose over a long period of time.
Play safe and be happy
Jim Vrzal
SteveB wrote:
Reply to
Mawdeeb
Agree. I have backflow preventers at the torch, and fire suppression arresters at the regulator.
Mawdeeb writes:
Reply to
Ole-Hjalmar Kristensen
Torch end. Putting them at the tank end does no good. Their purpose is to prevent mixing of gases in the hoses, so combustion can't occur in the hoses. The very high pressures in the tanks prevent backflow through the regulators, so backflow preventers don't do anything for you if placed at the tank end of the hoses.
Gary
Reply to
Gary Coffman
Nobody Knows?
Reply to
Tod Engine Foundation
I put mine just downstream of the regulators, before the hoses. The hoses haven't burned up yet, so I guess that was right!
--Winston
Reply to
Winston
It isn't. The only place mixed gases can be forced into a hose is at the torch end of the hose. If the tip becomes blocked, the higher pressure oxygen can flow through the torch mixing chamber and back into the lower pressure acetylene hose, forming a combustible mixture there. The check valves *at the torch* prevent this. Check valves at the regulators don't do anything useful.
Gary
Reply to
Gary Coffman

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