Acetylene minimum cyl pressure

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What is the minimum cylinder pressure for acetylene to prevent transfer of droplets to the torch? I know there are differing opinions, and I thought I read 20 PSI somewhere but now I can't find it.Also, where can I find some information on flashback arrestors and installation, and on torch check valves and how to make sure they work?Thanks, BMiller Challenger 172Miller Thunderbolt AC/DC 225/150Miller Maxstar 150 STLVictor 100CVictor JourneymanOxweld OAHarris O/ASmith O/A little torchNo, that's not my car.
Reply:The danger of drawing off acetone has to do with flow rates more so than a given pressure, altho higher pressures with a fixed outlet size would allow for higher flow rates, withdrawal rates are what you want to focus on. The 20 psi thing could be in referrence to the instability of acetylene at higher pressures while outside the stabilizing acetone environment. Some cite 15 psi, some cite slightly higher but somewhere in that range is where acetylene becomes unstable and volitile. The reason for the acetone to begin with."The things that will destroy America are prosperity at any price, peace at any price, safety first instead of duty first, the love of soft living and the get rich quick theory of life." -Theodore Roosevelt
Reply:Thanks Sandy. Actually this is what I was referring to: http://www.smokstak.com/forum/showthread.php?t=74170 scroll down to post #5Also, my Harris setup has Flashguards attached to the torch handles which are actually check valves from my understanding. Harris also recommends Flashback arrestors at the regulators. I was wondering how many actually have both, and also how to test my handle mounted Flashguards. Here are the Harris products:http://www.yellowpages.com.au/conten..._479913201.pdfMiller Challenger 172Miller Thunderbolt AC/DC 225/150Miller Maxstar 150 STLVictor 100CVictor JourneymanOxweld OAHarris O/ASmith O/A little torchNo, that's not my car.
Reply:Yeh, I've not heard of any reference to maintaning a minimum internal pressure for any other reason than to prevent inhaling and contamination when it gets opened. Not that there isn't something out there, I've just haven't seen it. It's always flow rate/withdrawal rate with little tie to the tank internal pressure."The things that will destroy America are prosperity at any price, peace at any price, safety first instead of duty first, the love of soft living and the get rich quick theory of life." -Theodore Roosevelt
Reply:We run them until they can no longer maintain a flame.  If you want a number for that, that would be between 3 and 5 psi.