Re: [APD] Re: Orientation of CO2 Tank

[Vaughn Hopkins <hoppy1 at surewest_net>]

The problem is that liquid CO2 gets extremely cold when the pressure is 
dropped through the regulator, and it changes to a gas.  It gets so 
cold that the liquid can freeze to dry ice.  The gas also gets cold 
when its pressure drops, but the amount of calories involved is a lot 
less.  Changing from a liquid to a gas uses up a lot of calories.  
Years ago I worked a bit with bottled CO2 as a source for gas to 
operate a wind tunnel with, to simulate Venus' atmosphere, as I recall, 
and that was one of the first lessons I had to learn.  You are getting 
away with it now because of the very, very low flow rate involved, and 
that might let  you get away with it forever, but it still isn't a good 
idea.

On Wednesday, February 16, 2005, at 04:01 PM, S. Hieber wrote:

> Did that say how many days it would take for this freezing
> to occur? It's been a few now and mine hasn't frozen.
>
> The liquid is the same temperature as the gas. The liquid
> is at the same pressure. I doubt that it will freeze
> anything. And if it did, that wouldn't be a cause for
> venting, it would just mean that either the it plugs up
> with ice until defrosted or would freeze at a given presure
> setting. But there shouldn't be much moisture in the CO2
> gas anyhow, so ice should not be forming anyway. If it
> does, then you probalby need to have the inside flushed and
> dried so that the water doesn't corrode the innards.
>
> Scott H.
> --- Tom Wood <tomwood2 at flash_net> wrote:
>
> > > No. The CO2 tank contains both liquid CO2 and gaseous
> > > CO2. When the tank is upright, the gas flows out of the
> > > regulator. But if used on their side, liquid will flow
> > > into the regulator, with bad consequences
> >
> > "Uh actuall not so, since the output pressure is the same
> > either way, all you get is gas going "through" the
> > regulator, i.e. through the metering orifice inthe
> > regulator and through the lowpressure side of the
> > regulator.
> >
> > If your CO2 is running, go turn the tank upside down and
> > see what happens."
> >
> > I just got a refill on my CO2 cylinder and asked them
> > what would happen.
> > They said that the mechanism inside the safety valve
> > would freeze up and
> > then start venting gas. The safety valve is the brass
> > nipple-looking thingy
> > with the holes drilled in it below and opposite the
> > connection fitting.
> >
> > TW
> >
> >
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>
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