why C02

Mathias Koerber said:

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.

Mathias Koerber said:

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).

"Ed J." <[email hidden]> wrote in message
news:[email hidden]

[...]

Quoted message said:

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*.

--

A: Top-posters.
Q: What is the most annoying thing on Usenet?

DRS said:

"Ed J." <[email hidden]> wrote in message
news:[email hidden]

[...]

Quoted message said:

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.

Quoted message said:

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 ([email hidden])

"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.

Leo Lichtman said:

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
[email hidden]

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.

--

Mathias Koerber said:

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

Mathias Koerber said:

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.

"A Muzi" <[email hidden]> wrote in message
news:[email hidden]

Quoted message said:

Mathias Koerber said:

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.

--

A: Top-posters.
Q: What is the most annoying thing on Usenet?

Mathias Koerber said:

What makes CO2 the more desirable gas for this use?

CO2 can exist as a liquid below 31 C, and since liquid is much more
dense than gas, lots of CO2 can be stored in a given sized
container. Nitrogen's critical temperature is -147 C, making its use
impractical without refrigeration.

The other nice thing about CO2 is it's essentially inert.

--
terry morse Palo Alto, CA http://bike.terrymorse.com/