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Thread: CO2 bottle angle

  1. #11
    maddox10's Avatar
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    @ Lee

    CO2 needs a lot of heat to evaporate.
    The few watts the ESC provides in heat are like a mosquito pissing in the sea.
    The complexity as well the vurnability of such a setup won't pay off.

    @ Yatcatcher.
    It all depends how the techcheckers interpret the setup. But any kind of deliberate active heating is prohibited.

  2. #12
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    Grin, not trying to get around the rules. Just find this rule could be interpreted in different ways.

    So for example if the aim is to prevent a valve from freezing up in use different methods could be used;

    - bolt the valve to a heat sink of some kind, maybe with some fins.
    - Use some electronic heating of some kind which only heats to ambient temperature
    - Use heat from other areas to heat the valve through positioning / fans

    Two of these would be legal and the other one not, even though they all in effect add heat to the valve / CO2 system.

    Other solutions, the cooling comes from the gas expanding and one of the places that happens is where the gas leaves the system, still under some pressure. So using a pipe to allow the system to vent at some distance from the valve area can help. Certainly allowing the system to vent near the valve will cause condensation and freezing to occur to a greater degree.

    One final thing (and it may be our imagination), but we switched from getting our pub CO2 bottle which we used to recharge our system, filled at the local welding shop to a fire extinguisher supplier, and the gas seemed to contain less water?!?!

  3. #13
    maddox10's Avatar
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    Talking as a tech checker with some knowledge about CO2 setups I can write this.

    Using fins to gather more heat from the enviroment, perfectly passive. No problem there according the rules.

    Active heating restricted to ambient temperature still is active heating.

    Fans to suck out the cold, should work, if designed well. And ain't active heaters.

    On the idea to expand gas away from the valve. It could work, but will degrade performance due long piping. At least for the first flips.
    I don't see a direct advantage, as the energy hungry transition between liquid and gas should happen in the main bottle or between main bottle and buffertank. Not between buffer and main ram feeding valve or even after main feed valve.

    Water in CO2 bottles. It's potentialy deadly. If you notice that, don't use the feed bottle, return to supplier, and ask for a refund. Check your setup thoroughly.
    Check all pressure parts on corrosion, and clean them. If pitting of inner surfaces is noticed, let the parts be rechecked by professionals that can provide official certificats.
    Be warned, most of the time they will recommend scrapping.
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  4. #14
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    Jeremy Cuss
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    I am at the point at which I need to decide whether to slope the CO2 bottle up or down or leave it horizontal. I have a full pressure system. Above the CO2 bottle I have 2 horizontal buffer tanks, each feeding a ram inlet valve. My intention was leave the CO2 bottle horizontal. On opening the isolation valve liquid will transfer to the buffer tanks and evaporate until the pressure balances. On opening the inlet valves the pressure in the system will fall and feed gas (and some liquid) to the ram. I have taken on board the point further up this thread that it would be good to direct the cold exhaust gas away from inlet valves. Any suggestions or advice would be welcome.

  5. #15
    maddox10's Avatar
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    You could add an "up tube" in the main tank. A dip tube bend so it will take gas when the bottle is in a normal position.

  6. #16
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    If it helps, my understanding is that in normal use a fire extinguisher has a dip tube that leads down to the liquid at the bottom. The pressure drop when the valve is opened means that gas is produced from the nozzle. This suggests that fire extinguisher valves are capable of running liquid or gas.

    CO2 becomes liquid around 750psi and we are required to have a burst valve if bottle pressure exceeds 1000psi which when a bottle is correctly filled should only happen in exceptional circumstances. When you open your isolation valve(s) to fill your buffer tank there is a greater volume for the CO2 to exist in which will allow some of the liquid to become gas (by volume about 50 times), each time you fire the weapon, some more of the liquid will evaporate to maintain the pressure at 750psi until it is all gas when the pressure will start to drop with each firing.

    To my mind it is probably best to flow gas and not liquid through the extinguisher valve, such is the pressure drop through the extinguisher and / or the isolation valves it is likely that the buffer tank side will be just see gas anyway. So if you are using a dip tube angle the extinguisher with the valve down (like Chaos2), without a dip tube angle the extinguisher with the valve up, or use Maddox' idea and bend the tubes so you can mount it horizontally. But I don't believe it's a make or break issue as the flow of gas through these valves is slow enough that it isn't an area I have seen a problem (I bow to anyone who's experience is different).

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