why C02

Mathias Koerber

and nor compressed air (for those cartridge inflators)..

What makes CO2 the more desirable gas for this use?

just curious...

Zog The Undenia

Mathias Koerber wrote:

> and nor compressed air (for those cartridge inflators)..
>
> What makes CO2 the more desirable gas for this use?
>
> just curious...

It's easy to get from compressed air, becuase it has a
fairly high boiling point. Also easy to store either as a
solid or a liquid.

Ed J .

On Sat, 26 Jun 2004, "Mathias Koerber" <mathias@koerber.org> wrote:

>and nor compressed air (for those cartridge inflators)..
>
>What makes CO2 the more desirable gas for this use?

Couple of things: CO2 is in the cannister as a liquid, when
it's released and turns to gas, it expands. CO2 maintains a
constant pressure until it's empty, unlike air which will
decrease pressure as it empties. Also iirc, in a container
of the same size, you get something like 17x more volume
from CO2 than you would with compressed air, which is why
one of those little cylinders can fill a tire. If you've
ever tried to fill a car tire with a 5lb air tank, you know
how poorly that works. On the other hand, offroaders carry
CO2 tanks to air up their tires for the ride home. A 10lb
tank can fill 33" tires from 12psi to 30psi around 4-5 times
(20 tires).

Drs

"Ed J." <ej_000@hotmail.com> wrote in message
news:b74rd0hu0c9e5n96isvnn32kk0csb6ultu@4ax.com

[...]

> Also iirc, in a container of the same size, you get
> something like 17x more volume from CO2 than you would
> with compressed air, which is why one of those little
> cylinders can fill a tire.

It's such a shame you can't breathe CO2 when scuba diving.
You could stay under for *hours*.

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John Thompson

On 2004-06-26, DRS <drs@remove.this.ihug.com.au> wrote:

> "Ed J." <ej_000@hotmail.com> wrote in message
> news:b74rd0hu0c9e5n96isvnn32kk0csb6ultu@4ax.com
>
> [...]
>
>> Also iirc, in a container of the same size, you get
>> something like 17x more volume from CO2 than you would
>> with compressed air, which is why one of those little
>> cylinders can fill a tire.

> It's such a shame you can't breathe CO2 when scuba diving.
> You could stay under for *hours*.

You know, if you *DID* use CO2 for diving, you probably
*WOULD* stay under for hours. If not years, if you catch
my drift...

--

-John (john@os2.dhs.org)

Leo Lichtman

"DRS" wrote: t's such a shame you can't breathe CO2 when
scuba diving. You could stay under for *hours*. ^^^^^^^^^^^^
Actually, you could stay under *forever*.

BTW, a very important reason CO2 is used for compact tire
inflators is that it is there. The cartridges are used for
pellet pistols, seltzer bottles, and who knows what, so they
are available.

Jobst Brandt

Leo Lichtman writes:

> BTW, a very important reason CO2 is used for compact tire
> inflators is that it is there. The cartridges are used for
> pellet pistols, seltzer bottles, and who knows what, so
> they are available.

Let's not lose sight of the correct answer Ed gave and that
is that CO2 is a liquid at these pressures and occupies a
tiny volume just as water does in comparison its gaseous
form (steam). Air cannot be reduced to liquid except at
impractically high pressures. Because refrigerants, like
ammonia or freon are borderline liquid/gases at atmospheric
temperatures and pressures, they lend themselves to phase
change cooling as they are compressed and expanded. You'll
notice that CO2 cartridges freeze when the contents are
released. That results from phase change of liquid to gas.
Of course just expanding a gas results in cooling but no
where near what phase change produces. Some gases cannot be
liquefied and are ill suited to these applications.

http://www.engineeringtoolbox.com/24_147.html

Jobst Brandt jobst.brandt@stanfordalumni.org

Weisse Luft

All gases can be compressed and refrigerated to condense into liquids and/or solids. Atmospheric gases like nitrogen and oxygen cannot be liquified at temperatures/pressures we would be content with...you would have to keep your cartridges deeply refrigerated, not something you would want to do on a ride. At normal temperatures, there is no container strong and light that could keep oxygen or nitrogen liquified.

But now CO2...its quite an odd mgas as it will exist as a solid or gas at normal pressures/temperatures or as a mix of gas and liquid of you get the pressure up to 800-1000 PSI(a). Since it can exist as a solid at atmospheric pressures, filling foil-sealed bottles is quite easy. Keep the containers cold on dry ice and weigh the contents. When the net weight of CO2 is right, crimp the seal. Voila, a 12, 16 or what ever mass of CO2 is sealed and easily used.

I've refilled 16 gram cartridges using liquid nitrogen to deposit CO2 into the cartridge. When I weighed 16 grams, I installed my inflator, sealed it and was done. Now I use 12 gram ones at $.50 per each, its far easier. But when the LBS was charging $4.50 for a 16 gram, flats were far too expensive.

A Muzi

Mathias Koerber wrote:

> and nor compressed air (for those cartridge inflators)..
> What makes CO2 the more desirable gas for this use? just
> curious...

In days of old, our refillable gonfleurs used nitrogen.

I think you'll find that CO2 is dirt cheap and ubiquitous
because the cartridges also fit BB guns, not because small
town hardware stores care all that much about cylists.

--
Andrew Muzi www.yellowjersey.org Open every day since 1
April, 1971

Werehatrack

On Sat, 26 Jun 2004 22:29:22 +0800, "Mathias Koerber"
<mathias@koerber.org> wrote:

>and nor compressed air (for those cartridge inflators)..
>
>What makes CO2 the more desirable gas for this use?
>
>just curious...

A greater amount of CO2 than air can be contained in a
cartridge of a given volume at the same pressure and
temperature.
--
Typoes are a feature, not a bug. Some gardening required to
reply via email. Surrealism is a pectinated ranzel.

Drs

"A Muzi" <am@yellowjersey.org> wrote in message
news:10dslqef5oiv3f4@corp.supernews.com
> Mathias Koerber wrote:
>
>> and nor compressed air (for those cartridge inflators)..
>> What makes CO2 the more desirable gas for this use? just
>> curious...
>
> In days of old, our refillable gonfleurs used nitrogen.

I think they should use helium.

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