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acetylene bottles lying on their side?

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  • acetylene bottles lying on their side?

    I have always been taught, read, and heard that if you ever tip an acetylene cylinder on its side (e.g. transporting it in a trunk) that you have to stand it up for 24 hours before it can then be used.

    Why? What bad thing happens if you don't?

  • #2
    The acetone in the bottle need to settle to the bottom, otherwise you end up releasing it along with the gas. Not good.

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    • #3
      Never heard the 24 hour thing but acetylene is unstable under pressure. To keep it stable the tank is filled with an absorbent material soaked in acetone. This allows the acetylene to dissolve in the acetone. If laid on it's side the acetone/acetylene mixture can escape through the valve

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      • #4
        If you need it right away don't transport lying down. If you can wait keep it vertical for the length of time it was on its side. The acetone should migrate at the same rate.

        I have always transported my bottles on their sides. No problems but I usually don't use them til the next day.

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        • #5
          I have repaired regulators with diaphragms/seals damaged from the acetone. That is another reason the regulator has a red line on it, you don't want to get ahead of the rate of seperation.
          re
          Herm Williams

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          • #6
            Originally posted by Herm Williams
            That is another reason the regulator has a red line on it, you don't want to get ahead of the rate of separation.
            re

            I don't understand what you mean by that?

            The red warning area has nothing to do with flow rate and is the excessive pressure warning area, flow rate can be easily exceeded at even lower pressures so staying out of the red area will not prevent excessive flow rates. This usually occurs with a high volume attachment like a heating tip but even a cutting torch can exceed the flow rate with a small tank and/or cold temperatures. In very cold weather Acetylene tank flow rates drop by a lot and using a large volume attachment can draw Acetone in those conditions when it might not if the tank was warmer. That red area is very important for the pressure setting however since Acetylene becomes unstable above 15 PSI and can self-ignite if it comes into contact with Oxygen, even small amounts of Oxygen entering the fuel line is bad enough under normal pressure settings but at over 15 PSI it can ignite without an external ignition source. In any case NEVER operate a torch with the regulator setting in the red area on the gauge!

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            • #7
              This observance has been from years back, early 60's or so, but I've seen pipeline welders with both tanks rigged horizontally on their trucks. I asked one if this wasn't dangerous, and he basically blew me off. So, just to be safe, if I've had a tank horizontal, I don't use it until it has been verticle for at least the same amount of time.
              John B

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              • #8
                [QUOTE=jr45acp[I]]This observance has been from years back, early 60's or so, but I've seen pipeline welders with both tanks rigged horizontally on their trucks. I asked one if this wasn't dangerous, and he basically blew me off. So, just to be safe, if I've had a tank horizontal, I don't use it until it has been verticle for at least the same amount of time.[/[/I]QUOTE]

                In the UK at any rate, its a Health and Safety contravention to store or use gas bottles (thats all gases, not just acetylene) other than vertical. They not only have to be vertical, but be restrained so they can't fall over. Even if they are chained to a trolley, the preference is for the whole thing to be chained to a column. Partly its because of the acetone issue with acetylene, the other is that if the valve on the top of the bottle gets damaged or knocked off, and the gas releases at high pressure, the whole bottle can shoot off sideways like a rocket. At least, thats what the H&S inspector told me last time I fell foul of them over gas bottles.

                Richard

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                • #9
                  Originally posted by jr45acp
                  This observance has been from years back, early 60's or so, but I've seen pipeline welders with both tanks rigged horizontally on their trucks. I asked one if this wasn't dangerous, and he basically blew me off. So, just to be safe, if I've had a tank horizontal, I don't use it until it has been verticle for at least the same amount of time.


                  The guy probably used only very little gas from that tank, I have seen several times people trying to use a tank on it's side and Acetone is almost immediately drawn into the regulators. Another fellow I know who has a construction equipment service truck has his tanks laying on their sides and he is completely ignorant to the problem! His truck and torch rig reeks of the odor (that stuff STINKS) from the bleeding Acetylene tank and his regulator is usually junked. When I asked him about regulator problems he commented about how everything is Chinese these days and that good equipment can't be found now. When I tried to explain that his problem was the horizontal tank he did as you said the pipe line welder did, he basically just blew me off" and acted insulted. I certainly did not force the issue and did not say anything else but the guy obviously does not know what he is doing and that pipe line welder sounds like he has a lot to learn also, of course some people learn all they are going to on the first day and after that no one can tell them anything.

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                  • #10
                    Originally posted by Radkins
                    That red area is very important for the pressure setting however since Acetylene becomes unstable above 15 PSI and can self-ignite if it comes into contact with Oxygen, even small amounts of Oxygen entering the fuel line is bad enough under normal pressure settings but at over 15 PSI it can ignite without an external ignition source. In any case NEVER operate a torch with the regulator setting in the red area on the gauge!
                    This is a misunderstanding of the explosive hazard associated with acetylene. Acetylene is a metastable chemical compound. It will spontaneously dissociate under pressures around 30 psi if it isn't in very close contact with stabilizing surfaces. That dissociation has no dependence on contact with other elements such as oxygen and is not a combustion reaction either. It requires no oxygen to occur and is a high explosive detonation in the same manner as nitroglycerine.

                    The pressure limit of 15 psi is used to provide a safety margin at normal temperatures.
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                    • #11
                      correct... even a tightly closed bottle can go off on its own in the wrong circumstances....& that does not mean in a fire. IIRC even a hard knock can potentially "set one off", particularly if the acetone or core is damaged.

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                      • #12
                        I keep all my bottles upright, Even the argon for my welder, Because having the valve at ground height would make it a LOT easyer to drop something on it or smash something into it without looking. I sure would love to have it tucked under my welder on a cart, but its just not safe.. Not to mention, With the regulator down there, id never remember to shut the dang thing off.
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                        • #13
                          One of the reasons for the odd angled valve on MC tanks is because they were intended to be used at an angle, as in attached to a motorcycle frame, thats where MC comes from.

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                          • #14
                            Originally posted by metalmagpie
                            I have always been taught, read, and heard that if you ever tip an acetylene cylinder on its side (e.g. transporting it in a trunk) that you have to stand it up for 24 hours before it can then be used.
                            The AWS/CGA recommendation is 15 minutes for every 15 minutes the bottle was on its side in transport.
                            "Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did."

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                            • #15
                              Originally posted by Evan
                              This is a misunderstanding of the explosive hazard associated with acetylene. Acetylene is a metastable chemical compound. It will spontaneously dissociate under pressures around 30 psi if it isn't in very close contact with stabilizing surfaces. That dissociation has no dependence on contact with other elements such as oxygen and is not a combustion reaction either. It requires no oxygen to occur and is a high explosive detonation in the same manner as nitroglycerine.

                              The pressure limit of 15 psi is used to provide a safety margin at normal temperatures.

                              Lots of misunderstandings about Acetylene and other gases sometimes these are even in printed manuals such as what I was saying about the Acetylene, I have read that more than once- which of course does not make it so.

                              Your explanation actually clears up something else I have wondered about in the past and that is how the Acetylene could explode at about 30 PSI (I was quite aware of the safety margin) in a hose but not in the tank at it's much higher normal pressure since not 100% of the gas will be dissolved in the tank at all times. The only explanation was the one about Oxygen being introduced into the gas contained in the hose but there are many problems with that reasoning, still until now that was the only explanation I was aware of and it is quite common even if wrong which apparently it is, once again I have learned something and you have corrected me on a long held misconception about acetylene.

                              The point I was actually trying to make however is that relying on the red warning zone (and that is a "warning not to use" and not "use with caution" as some seem to think!) to prevent overdrawing the tank will not work. Overdrawing the the tank is of course a function of too much volume over a given time period and not how much pressure being supplied to the torch.

                              .
                              Last edited by radkins; 12-14-2010, 05:36 PM.

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