how dangerous is it if someone runs too much pressure? I noticed a coworker whose cutting outfit had a broken acetelyne pressure guage on his regulator today. I fixed it, but was wondering if anyone knows definitively from experience what can happen, and how much is too much?
Acetelyne explosion?
daddy
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denrep said:Bill,
By the nature of a liquid, oil in this case, it can only burn on it's surface area, which is exposed to oxygen. When water is thrown onto burning oil, it displaces oil, thus increasing the surface area available to burn.
This is more commonly known as ARC (Added Refluent Combustion) effect!:blob4:
You can see that the pressure is coming from inside the pot. There is no air flow into that blue stream. If anything it is expanding beyond the walls of the pot. Not sucking air into it.
I know torches pretty well after using them for many years. And you can get a somewhat blue flame by putting to much acetylene pressure into a cutting torch. However if you look at the aerodynamics of that, the air is in fact being sucked in. But into an area that is not burning. Into a negative pressure zone.
Obviously there is not a negative pressure zone with all that steam pressure. I find it odd that you would attack that without going over the obvious.
Oxygen cannot feed the outside of a large column like that and turn it blue. That is the oxygen in the water. If I get a chance I will feed a hot plumbers torch with steam and video it. I will be able to turn the flame blue and yellow back and forth. With no change in surface area.
But if you look at that movie you can see that the blue flame comes out of the pot under pressure. Not sucking in air at all.
Sincerely,
William McCormick
Johns example spelled out 10 SCFH at 3 psig and 16 SCFH at 6 psig. His example also showed draining a 145 cu.ft cylinder in 1.45 hrs or .9 hrs respectively. So yes, if you stay within the parameters John listed, you could run that particular tip continuously till the tank was empty.daddy said:
Bill, I don't want to steal this thread.William McCormick Jr said:
We can discuss water burning and such, here: http://www.weldingweb.com/showthread.php?t=18170
I no doubt got the math wrong.
moved the decimal. Anyway, it's a matter of dividing your tanks cubic feet capacity by the draw of your tip................145 cubic foot quals tank divided by 10 cubic feet per hour equals 14.5 hours of straight cutting time. A 145 cubic foot tank divided by 16 cubic feet per hour equals 9.0x hours.Ok, here we go again,...
I'll set the stage first.
O/A outfit lives outside in PA winter. Regulators are exposed to freezing rain with no protection. 100' hoses. Flashback arresters on output of regulators before hose. No. 2 Victor cutting tip.
Torch operater,(NOT ME!) is burning bolt holes in top of I beam to accept housing that is sitting on the beam. The housing is 3/8" plate and there is a shim of 1/2" plate under it,both with holes punched already, so he has a hole of almost one inch deep that he is stuffing that tip into to cut the matching hole in the beam.
I'm doing other things and look up to see torch operater with torch spewing black soot in the same way that a properly adjusted torch burns a flame. Being a safety conscious fella, of course, I calmly reach over to the acetylene tank and close the valve as quickly as I can, then close the Oxy. tank. In the mean time he had closed the valves on the torch, but when he opened them again he still had black soot shooting out of the torch full force. With the tanks both shut off, I felt slightly safer, and figured that if there was a fire in the hose we should disconnect it from the regs, so that is what I did. Some soot emerged from the fitting when I unhooked the acetylene hose from the reg, but no fire or flames.
The regulators and flashback arresters were taken inside and de-thawed with copious amounts of water emerging from the acetylene reg especially, and the torch tip was thoroughly cleaned.
Given the deep holes that he was trying to start a piercing cut inside, I'm sure he was backfiring the torch.
I reinstalled everything after water mitigation, and used the setup with no problems for an hour or two for other things.
What happened? Was there a fire in the hose? Did the flashback arresters save my ***?
Why does the torch always work fine for me, without making me sh*t my pants?
This guy also has a torch "cleaning technique" that involves purposly backfiring the torch on a piece of wood taught to him by an old ****.
Being of Italian descent myself, I hope none of my uncles used this trick. I never have.
Sorry, had to vent a wee bit.
I'll set the stage first.
O/A outfit lives outside in PA winter. Regulators are exposed to freezing rain with no protection. 100' hoses. Flashback arresters on output of regulators before hose. No. 2 Victor cutting tip.
Torch operater,(NOT ME!) is burning bolt holes in top of I beam to accept housing that is sitting on the beam. The housing is 3/8" plate and there is a shim of 1/2" plate under it,both with holes punched already, so he has a hole of almost one inch deep that he is stuffing that tip into to cut the matching hole in the beam.
I'm doing other things and look up to see torch operater with torch spewing black soot in the same way that a properly adjusted torch burns a flame. Being a safety conscious fella, of course, I calmly reach over to the acetylene tank and close the valve as quickly as I can, then close the Oxy. tank. In the mean time he had closed the valves on the torch, but when he opened them again he still had black soot shooting out of the torch full force. With the tanks both shut off, I felt slightly safer, and figured that if there was a fire in the hose we should disconnect it from the regs, so that is what I did. Some soot emerged from the fitting when I unhooked the acetylene hose from the reg, but no fire or flames.
The regulators and flashback arresters were taken inside and de-thawed with copious amounts of water emerging from the acetylene reg especially, and the torch tip was thoroughly cleaned.
Given the deep holes that he was trying to start a piercing cut inside, I'm sure he was backfiring the torch.
I reinstalled everything after water mitigation, and used the setup with no problems for an hour or two for other things.
What happened? Was there a fire in the hose? Did the flashback arresters save my ***?
Why does the torch always work fine for me, without making me sh*t my pants?
This guy also has a torch "cleaning technique" that involves purposly backfiring the torch on a piece of wood taught to him by an old ****.
Being of Italian descent myself, I hope none of my uncles used this trick. I never have.
Sorry, had to vent a wee bit.
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When you burn acetylene and oxygen you get water.
If you have a welding blanket fold it to about four layers thick, and put it on a piece of metal. Then put the acetylene torch to it, for just a second or two. You will find the metal is all wet. It creates an enormous amount of water in a few seconds. Normally you do not get to see it because it turns to steam.
Sincerely,
William McCormick
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It was from a time when you had no time on the job to fiddle with the one set of twisted or broken cleaning kits.
Those guys were probably over worked. And resorted to things like that to clean the torch in hurry.
I have over the years in frustration rubbed it across a steel plate while it was lit. It pops a few times and often blows out the carbon or metal ball, lodged in one or more of the heating orifices. Sure it is dead wrong, but when you are in a hurry, you do dangerous things.
More often then not it makes it worse or ruins the tip so you cannot clean it with a cleaning kit.
Sincerely,
William McCormick
I don't know what browny thinks but for me its a no thanks
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McCormick,
Did the bus you rode to school look like this?
![Image]()
Did the bus you rode to school look like this?
Man - Look at the huge hubs and rubber on that bus. Whoever spec'd that baby wanted it to have brakes! Probably from mountain country.McCormick,
Did the bus you rode to school look like this?
![Image]()
Better have plenty of acetylene on hand, when you try to take those rusty old wheel nuts off... So you don't blow your mind!
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No I don't think we went to school together.McCormick,
Did the bus you rode to school look like this?
![Image]()
Sincerely,
William McCormick
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C2H2 -- Dissolved Acetylene , meaning 2 kg of acetone hold a kg of Acetylene... a normal bottle at my place need 14 kg of acetone to dissolve 7 kg of the gas... u get +/- 6-6.5 kg worth of welding dissolved acetylene...
If someone decided to reduce the acetone or not refill due to addition cost of acetone then you get not the full amount... the acetone act as a catalysis ...
I have seen some shady operator making customer believe that pressure is an indicator of volume... like O2
Anyway, the catalysis make the gas stable, without acetone the acetylene wouldnt be fill... do the math above.
---------------------------------------------------------------------------
I have seen acetylene leak and the cylinder just fly and stuck to the roof until it subside... nothing unusual in old days... hard to see now.
The cylinder have a safety protection on the valve that will burst and let the gas away.
when you see a torch light because you forget to tighten the handle and was llighted by stray grinding spark or other strange source... which could lead to flame... calmly walk to the cylinder and turn the main valve off and you will save a lotta shock.
Never store huge amount of O2 and C2h2 within 15 meter limit...
degrease yourself often as welding environment is very dangerous with your hand full of lubricant or grease...
I hope I have not bored you all... err... back to my cage
If someone decided to reduce the acetone or not refill due to addition cost of acetone then you get not the full amount... the acetone act as a catalysis ...
I have seen some shady operator making customer believe that pressure is an indicator of volume... like O2
Anyway, the catalysis make the gas stable, without acetone the acetylene wouldnt be fill... do the math above.
---------------------------------------------------------------------------
I have seen acetylene leak and the cylinder just fly and stuck to the roof until it subside... nothing unusual in old days... hard to see now.
The cylinder have a safety protection on the valve that will burst and let the gas away.
when you see a torch light because you forget to tighten the handle and was llighted by stray grinding spark or other strange source... which could lead to flame... calmly walk to the cylinder and turn the main valve off and you will save a lotta shock.
Never store huge amount of O2 and C2h2 within 15 meter limit...
degrease yourself often as welding environment is very dangerous with your hand full of lubricant or grease...
I hope I have not bored you all... err... back to my cage
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I will tell you though, I would have been afraid to sit in the back of the bus. Ha-ha.Sorry you missed it. The bus was a great time.
![Image]()
Sincerely,
William McCormick
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I agree, There is always a fudge factor built in to these limits. Smith Torch chart lists 15 psi as recommended pressure for rosebud type tips on acetylene and oxygen. In the UK the limit on max acetylene pressure is greater. But to play it safe,,,just play by the rules and keep it at 15psi or less.
here are some good welding safety tips...pretty funny too.
http://www.weldingtipsandtricks.com/welding-safety.html
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