CO2 in Bottles

  1. pdg

    pdg Member

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    MOD - Moved these posts from another thread to prevent the latter going off topic

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    They work at exactly the same pressure...

    Both pub co2 bottles and fire extinguishers store the co2 as a liquid, and you can't compress a liquid.

    The difference is that an extinguisher has a dip tube so the boil off happens in a different location compared to a non-dip cylinder.

    It's not the working pressure of the regulator that's an issue at all, it's the fact you might freeze it by using it on am extinguisher.
     
    Last edited by a moderator: Mar 20, 2017
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  2. Mee Banned

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    Unfortunately not, while the standard pressure may be around 55 bar not everyone works to the standard pressure and cylinders working higher than this are still in circulation and often given away or dumped.

    Actually its both, CO2 freezing is an issue with any type of CO2 and the pressure becomes an issue if a high pressure or non standard bottle is used.
     
  3. pdg

    pdg Member

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    When you show me a link or a reference to a way to store liquid co2 at higher pressures without the use of refrigerated storage facilities I'll believe you.

    In much the same way, a photo of you putting 2 litres of water into a 1 litre bottle at room temperature will suffice.
     
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  4. Mee Banned

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    I once did a contract at a bottle manufacturer and back then they produced a number of cylinders for CO2 or multi use which included CO2 in a range of sizes and ratings.

    Steel - 75 bar, 100 bar, 125 bar, 150 bar, 200 bar, and 250 bar.

    Alloy - 60 bar, 85 bar, 120 bar, 150 bar.

    Since then they have moved forwards as all cylinder manufacturers have and they do a new range including alloys they have developed themselves and they do both steel and alloy bottles to 300 bar, and their new range of ultra lightweights are a composite which are also rated at up to 300 bar which rather discounts your earlier post.
     
    Last edited by a moderator: Mar 20, 2017
  5. Morris Member

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    Liquid CO2 at 20deg C is at 57bar.

    "The pressure in a CO2 cylinder depends

    solely on temperature. At 20°C, for example,

    it is 57 bar. Even an almost empty CO2

    cylinder remains at 57 bar at 20°C, as long

    as it contains the liquid phase. This means

    that the contents of a CO2 cylinder cannot

    be determined by measuring its pressure,

    but only by weighing." http://www.linde-gas.pt/internet.lg.lg.prt/en/images/Safety_Advice_12303_25938.pdf?v=2.0

    If you want to argue with Linde feel free.
     
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  6. daleyd

    daleyd Member

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    What have the bottle ratings got to do with physics? Manufacturers may use higher rated bottles (they of course would build in a high safety margin in) but that doesn't mean they necessarily have to be filled to that pressure.

    At room temperature co2 cannot be stored at more than around 55bar - im not sure what part of this you don't understand? A co2 bottle should be filled about 2/3 in liquid with the remainder as a gas on top.
     
  7. pdg

    pdg Member

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    And right just exactly here is where you prove that while you may very well have a little knowledge it's limited and subject to uninformed extrapolation.

    Yes, the cylinders they whack co2 into are very often rated for higher pressures.

    For instance, I have a BOC Y cylinder of argon mix, it contains a small percentage of co2 but because it's at contaminant levels rather than the majority element it is not subject to pressure induced liquidation. The mix is put in the cylinder at a nominal 230bar.

    BOC use exactly the same cylinders with a different valve coupling to supply co2. If filled with co2 the pressure is, guess what? 57bar @ 20°c.

    Those composite bottles, they're rated at over 300bar. You can put something like argon in them at 300bar and be safe. Put co2 in there and if it's 20°c you won't get more than 57bar in because it'll be a liquid and you can't compress a liquid.

    The only way to get co2 stored in a cylinder at a higher pressure is to add another substance that will either remain separately gaseous at higher pressures or mix with the co2 and force it to remain in it's gaseous state - I really don't see what benefit that could provide in an extinguisher...
     
  8. mpats

    mpats Forum Supporter

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    Aberdeen
    Well said.

    And that's why every C02 extinguisher annual inspection I've ever done and signed for is done by weighing the extinguisher and making sure it hasn't gone down by more than a certain percentage of the original weight. What with the px gauge always showing in the green at around 50something bar (hangars are rarely 20C) you can only tell if you have lost anything from the contents is by the change in weight.
     
  9. Parm

    Parm I only give advice if I know

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    Being a major supplier of industrial and specialist gases that ive known and used in the past, I certainly wouldn't argue with Linde, or any other gas supplier. They are the specialists
     
  10. The_Yellow_Ardvark

    The_Yellow_Ardvark If in doubt ask.

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    All CO2 extinguishers. be them hand held, or on a suppression system, as you say are weighed. Plus they all have a life.
    Same with liquid and powder extinguishers.
     
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  11. The_Yellow_Ardvark

    The_Yellow_Ardvark If in doubt ask.

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    @pdg
    The reason why you have bigger CO2 extinguishers is to allow more weight of liquid CO2 in a can. This will give you a longer discharge time. Thus a better chance of extinguishing the fire.
     
  12. Parm

    Parm I only give advice if I know

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    On a slightly different one. Fuel gas such as propane and butane is also sold by weight. For example 13 and 19 kg propane cylinders. I belive the gas is compressed resulting in a liquid which then gives you the weight of contents. I trust C0 2 is the same
     
  13. WorkshopChris Forum Supporter

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    Used to have big CO2 extinguishers on site, the cylinder was at about 45 deg on a trolley with car size wheels.
    Hose was about 3m long with a big valve and horn. Absolute beast of a thing. Useful when welding in a oily press shop.:flame::welder:
     
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  14. the snooper

    the snooper getting older by the day

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    and different again, frozen Co2 is dry ice :D
     
  15. Parm

    Parm I only give advice if I know

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    It is indeed
     
  16. The_Yellow_Ardvark

    The_Yellow_Ardvark If in doubt ask.

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    It is @Parm
     
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  17. HughF

    HughF Member

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    You know, the very best feature of this forum software is the 'ignore' feature :P
     
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