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CO2 regulator

Discussion in 'Shop - Fabrication' started by subrunner, Apr 6, 2005.

  1. subrunner

    subrunner Member

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    May 28, 2004
    Location:
    Alta Loma,CA
    I've been looking for a regulator for the CO2 tank I picked up at the Offroad Swapmeet and every one I find has a flow gauge on the outlet. Are these pressure regulators or do they just have an adjustable orfice? I've looked at the welding shops($80) and Harbor Freight($29.99). I'm wondering if I can just swap out the flow gauge for a pressure so that I can regulate it down to 90# and run air tools.
     
  2. mgobaja

    mgobaja Well-Known Member

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    Yucaipa, CA
  3. tedmales

    tedmales Member

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    yuma az
    if you ran air tools you would freeze up the regulator
     
  4. mgobaja

    mgobaja Well-Known Member

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    If the bottle is standing ( Co2 ) it is less likely to "freeze" up as quick. I have had good success changing up to 4 tires, one right after another, without having any issues.

    Nitrogen is a way around the "freezing" issue as well, but to store the same volume you need a larger cyclinder then you do with Co2.
     
  5. Chase 2

    Chase 2 Well-Known Member

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    Jan 8, 2005
    Location:
    Simi Valley, CA
    The freezing issue with CO2 comes from the fact that under pressure the CO2 is liquid. With standing the bottle upright you are less likely to have liquid CO2 hit the regulator.

    Also be careful with buying 2nd hand CO2 bottles, there are some out there which actually have a syphon tube to specifically allow the transfer of liquid CO2. Recreationally, the syphon tanks are used by paintballers.

    Nitrogen is much perfered, but it only is kept in the cast iron bottles, not the trick looking (and much lighter weight) aluminum. I've had Nitrogen freeze up a die grinder while trying to cut the Kevlar belting from a flat tire wrapped around an axle.
     
  6. tmathews

    tmathews Well-Known Member

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    Feb 2, 2005
    Location:
    Alpine, Ca
    Nitrogen is the prefered choice, but you get more volumn on a CO2 bottle. Call the guys over at WSE.. Their prices can't be beat and their customer service is awesome. Their ph# 619-575-4000.
     
  7. roach

    roach Member

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    Sep 18, 2003
    Location:
    san diego
    i know someone who is looking for a flow meter and has a gauge regulator in exchange if you are interested. pm me and i can call him.
     
  8. Ramsey_ElWardani

    Ramsey_ElWardani Ironman

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    Apr 1, 2001
    Location:
    Carlsbad, CA
    I have used a 125 Psi Preset Pressure Regulator on a CO2 Tank for years and think it is the way to go. There are no gauges to break and they are very durable and safe. Got it at a Welding Supply House (WSE in San Diego) for just under $30. I use the CO2 for just about everything in the field you can think of, Air Tools to Airing up. The reason that you want to use CO2 over Nitrogen are several. CO2 is cheaper, safer and lasts longer. Nitrogen is stored in compressed form as a gas at up to 2000 PSI so breaking a valve off could be catastrophic. CO2 is stored in compressed form as a liquid at around 800 PSI. Because it is stored as a liquid the same size tank can hold more cubic feet of gas. The gas that is released from the tank is evaporated off the top of the liquid CO2 at an almost constant pressure of I think 600 PSI at a given temperature until all the liquid is gone. The Nitrogen bottle will have half the original pressure when half the original volume is used. The only way you can tell how much Nitrogen is left in the tank is by the tank pressure, so a gauge is necessary. With CO2 you can only tell how much is left in the tank by weighing it. Freeze-up has not been a problem, even using impact guns. Both Nitrogen and CO2 can cause Freeze-up; it is the release of the pressurized gas (just like in your Air Conditioning) that creates the temp drop. It has nothing to do with the fact that CO2 is stored as a liquid. By the way there is very little moisture (H2O) in CO2, less than 15 Parts per Million in Industrial Grade CO2 which is 99.5% pure. You can also get Instrument Grade which is 99.98% pure. Liquid CO2 is heavier than water, so if there were any moisture in the tank it would rise to the surface and blow off first. The moisture that most people see when working with CO2 is condensation from the air. When CO2 is released from its pressurized liquid form as a gas there is a rapid temperature drop which condenses the moisture in the surrounding air. The moisture is not in the CO2.
     
  9. scottm

    scottm Well-Known Member

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    scottsdale AZ
    Actually it does have to do with the co2 being in liquid state. The liquid vaporizes to gas by boiling, which carries away heat energy with the vaporized gas. This causes the temperature of the tank and the liquid co2 to drop. If it drops enough, the liquid co2 can change to solid, or dry ice. This is the real reason of concern when talking about the co2 "freezing up". If it does, you are done until it thaws, which can take a long time. I worked with liquid co2 for shielding gas in an experimental brazing oven. This system drew liquid from the bottom of the tank and vaporized it outside the bottle in a big finned evaporator. The evaporator would become covered in frost in just a few minutes. The tanks with a liquid tube are called a dip tube tank. Look for the letters DT on your bottle - if so the co2 will vaporize after the regulator, which can freeze your hoses to something like -50° and make them crack, or make your impact wrench verrry cold!

    The process of vaporizing co2 creates powerful cooling in the tank. Its no trouble to fill several tires or run tools for a couple minutes, but watch for frost to form on the outside of the bottle. You want to slow down the use if it does.
     
  10. mattb

    mattb Active Member

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    Poway, CA
    On this note.. I have a question. Why is it that whenever I fill a tire with CO2, it seems to go down over a matter of time. It doesn't matter if it has a leak or not, it just goes down.
     
  11. tmathews

    tmathews Well-Known Member

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    Feb 2, 2005
    Location:
    Alpine, Ca
    I believe your answer is a molecule problem. Nitrogen vs. Carbon Dioxde.
     
  12. FullsizeFun

    FullsizeFun Member

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    Mar 30, 2004
    Location:
    South Bay, Redondo Beach
    I have a small co2 tank for a mig welder. Can i take this to a welding supply and have it filled with nitrogen? or is it a different tank?
     
  13. ZTFab

    ZTFab Active Member

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    Dec 6, 2004
    Location:
    San Dimas, CA
    Most welding shops/gas suppliers will trade bottles out for whatever you want...I just traded an oxy tank for helium yesterday.....as long as you own the bottle, most suppliers will do it and just charge you for the refill of whatever gas you need, some will even let you "trade-up" to a bigger size bottle and just pay the difference..it depends on where you go...

    ...and if the bottle is "out-of-date" it's like $11 to have them recertified
     
  14. Curtis Guise

    Curtis Guise Administrator

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    Mar 22, 2001
    Location:
    Oceanside, CA
    I was told that Nitrogen gas is deadly to breath and not the best choice for running air tools. The same person told me that they changed out fittings on Nitrogen lines at refineries because people were hooking up their air tools to it and once you take a few breaths of the exhaust from the air tool its enough to kill you.

    can anyone confirm that?
     
  15. tmathews

    tmathews Well-Known Member

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    Alpine, Ca
     
  16. Ramsey_ElWardani

    Ramsey_ElWardani Ironman

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    78% of the air we breathe is Nitrogen, and only 21% is Oxygen. The other 1% is made up of lots of stuff (technical term) including other gasses. Nitrogen is colorless, odorless, tasteless, and nontoxic, it exists as a non-flammable gas at atmospheric temperatures and pressures. Although nontoxic and inert, nitrogen can act as a simple asphyxiant by displacing needed oxygen in the air.
     
  17. Ramsey_ElWardani

    Ramsey_ElWardani Ironman

    Joined:
    Apr 1, 2001
    Location:
    Carlsbad, CA
    You are correct in that the evaporating of CO2 gas off the liquid CO2 does cause cooling, just like water evaporating off your skin causes cooling that can be felt. The cooling from evaporating is minimal compared to the cooling effect in the regulator, hose and tools from auto-refrigeration as the compressed gas is expanded. This is the “Freeze-up” that most are concerned with. In my experience, the bottle itself does not get that cold. CO2 turns to "dry ice" at -78.5ºC (-109.3º F) and I believe it would be impossible for a 10Lb CO2 bottle to get that cold before running out of CO2.



    Here are some interesting sites:



    http://www.powertank.com


    http://www.warpig.com/paintball/technical/gasses/co2dynamics.shtml


    http://www.uigi.com/carbondioxide.html

     
  18. ZTFab

    ZTFab Active Member

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    Location:
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  19. subrunner

    subrunner Member

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    May 28, 2004
    Location:
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    That's part of the reason. When you inhale pure nitrogen, you don't exhale CO2. Your body needs to see some amount of CO2 when you exhale. This is where your brain gets the signal to continue breathing. So basically, 1 breath of pure nitrogen and you stop breathing even if the air clears, you better hope you have a buddy near by.

    There was a guy at a BP refinery in Texas who died last year. There was a big vessel that was being purged with N2 and he looked into the manway on top, got a good shot of N2, passed out, and fell through the manway 60' to the bottom.

    I work at a refinery and we use alot of N2 during maintenance procedures, so we're all pretty familiar with it.

    Back to the topic, I guess I'll get the preset regulator.
     
  20. CRAIG_HALL

    CRAIG_HALL Well-Known Member

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    Oct 28, 2002
    Location:
    San Diego

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