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  1. #16
    BobL is offline Member: Blue and white apron brigade
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    Quote Originally Posted by franco View Post
    Bob,

    FWIW I have two copies of the old CIG instruction books for oxy acetylene welding and cutting several editions apart. Both state in bold type "never open a cylinder valve more than 1 1/2 turns." I was taught this at Tech too, but quite some time ago.
    I have since followed this up and found out that all modern valves have what is called a "double seat". There's a front seat that seals the bottle when closed, and a back seat that seals the valve stem o-ring when fully open. The recommendation is that all cylinders (except fuel gases) be fully opened to get this level of sealing.

  2. #17
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    RE : The half turn of the valve.


    That statement refers to the days when cylinder valves where operated by a key which fitted a square shank. When the cylinder had to be shut down quickly the 100mm long key made it just that much harder to do it quickly if more than a few turns were needed..

    Hence the advice to only open the valve to half way. To understand fully you need to have experienced how difficult is was to do quickly when you had a fire or emergency that required a quick shut down.

    GRAHAME

  3. #18
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    When I was working in the shop 40-45 years back we did exactly as Graham said. I carried that over to my own bottles in my shed many years later. A sad fact is that not all CIG bottles were leak proof. I had a couple of cylinders slowly leak all the gas out over a period of months when I was in Katherine. The CIG gas supplier just wasn't interested so I shut down my account and returned the bottles.

    Safety in the workplace, not where I worked, some dill actually welded a tab on a bottle! The shop emptied real quick when everyone realised what he was doing.

    On another occasion a hot bit of metal, just cut, fell on the hose igniting the gas. That was exciting! Bob the foreman managed to shut down the bottle before the flame got to the gauges. That's why we never opened the bottles more that a quarter turn and always left the key in the tap. The speed the flame worked it's way up the hose was something to behold.

  4. #19
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    Yes I only ever open my oxy about 11/2 turns and have done for years not sure whether I read about it or at T.A.F.E. Seem to recall that that number of turns will give you both the necessary volume as well as the right pressure but is much quicker to turn off in an emergency.Not sure whether that still applies to those those large heating lances as I have never used one but I assume it possibly could need to be opened more

  5. #20
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    Sacc51
    Being the same vintage as myself you may remember the oxy acetylene trolleys that had the big motorcycle wheels.

    CIG Monitor gauges were the vogue then.

    I set the acetylene cylinder on fire on such a trolley. The trolley was on the far side of a set of wooden flash screens and the grinder sparks from the work I was on went over the screen.

    Unfortunately someone had placed the trolley there after I was in position working, so I had no idea it was there. The set had a welded tray with sides 150mm or so high and long enough to take a torch with the Comet 3 cutting head in it.

    The torched leaked enough to ignite when the sparks hit. With helmet and ear muffs on and my back to the screens I was fairly oblivious to the 3 metre flames leaping from the oxy acetylene set until somebody had the presence of mind to throw some wood packers over the screens at me.

    The pressure blew the lead safety pug in the cylinder collar and the flame spewed upwards and melted the Monitor gauge down the side of the acetylene cylinder. It took the plant fire crew to put that one out.

    That was my close call with oxy acetylene. We wrote an amended JSP (Job Safe Practice) document after that one and went around the plant altering trolleys built in that way.

    Grahame

  6. #21
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    Quote Originally Posted by sacc51 View Post

    Safety in the workplace, not where I worked, some dill actually welded a tab on a bottle!
    2003 Darwin Award: Master Welder
    Gold, the colour of choice for the discerning person.

  7. #22
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    Quote Originally Posted by .RC. View Post
    My dad told me about a boilermaker that he worked with once. He was welding with some oxy gear and hose sprung a leak, so dad tells him to stop welding until he found the leak in his hose. Old mate cracks the valve on the acetylene tank and proceeds to run his lighter underneath from one end to the other along the hose. I think dad set some sort of land speed record while he was running away from, and yelling at old mate.

  8. #23
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    Like... I guess I've seen worse necroposts before. So I'm not leaving entirely disappointed.

  9. #24
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    Default Ignorance was bliss.

    Quote Originally Posted by .RC. View Post
    That reminded me of an episode I read about many years ago. It seems that The Factory Inspectorate visited a large industrial site to do their annual checks, and the large 20 tonne L.P.G. tanks were being examined for any possible defects. The inspectors backside started to quiver when he noticed the newly installed handrail, all freshly painted white that had been welded to the tank. As I recall, the joint was shut down and evacuated while a crew was bought in to decant the tank of L.P.G and the now condemned tank was removed.

  10. #25
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    Dec 2011
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    Lancaster, Ohio, USA
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    A bee crawled up into an oxy cylinder valve over here. Someone changing a tank out put the regulator on and did not notice it. Opened the valve and it blew the valve apart killing the person.

    Had a fire at a cylinder filling plant here years ago. The cylinders were heated up to max and then blew up. One went 15 miles, from mid town Columbus Ohio to Grove City, don't see how but They have an old newspaper clipping saved on the wall.

  11. #26
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    Quote Originally Posted by franco View Post
    Bob,

    FWIW I have two copies of the old CIG instruction books for oxy acetylene welding and cutting several editions apart. Both state in bold type "never open a cylinder valve more than 1 1/2 turns." I was taught this at Tech too, but quite some time ago.

    Frank.
    Same Here, Was taught to only open valve less than 1 turn so if needed bottle can be quickly shut off. Not needed these days but was also taught to leave the "key" ( square holed bottle valve hande ) in place on valve.

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