Uni-Vibe

If it'll pump up a 23C to 130#, it's gotta be around 2000 psi. Just guessing, the tire looks about 15 times the size of the cartridge. Does anybody really know?

Juan Foote

The pressure of CO2 is dependant on the ambient temperature. The powerlet holds 12 grams of liquid. IIRC, at around 70* the powerlet should be at around 700 or so PSI, less when colder, more when hotter.

Yellowbeard

You sound like you shoot.

If it were air, then yes. It's CO2, so no. Like Punkcat says, it's 700-800 PSI +or- depending on temperature, and mostly liquid. That's why your inflator will start spitting dry ice if you turn it upside down.

Juan Foote

Long time paintballer.

Grumpy McTrumpy

CO2 and Pressure
CO2 is a gas at temperatures above -69.9 degrees F and 60.4 psig (pounds per square inch gauge). It is a very complex compound with the ability to sublimate (change directly from a solid to a gas without becoming a liquid) as just one of its unique properties.

At 70 degrees F, CO2 obtains a gas pressure of 852.8 psi when confined in a vessel. If there is more CO2 in the vessel, it will be have to be in liquid form. So, the state of CO2 in a pressure vessel, such as a powerlet at room temperature, is a pressurized gas above a liquid. If the gas is released, such as through the operation of an airgun valve, some of the remaining liquid flashes to gas until the pressure is equalized for that temperature.

source

Phantoj

Why does the inflator make ice if you turn it upside down?

Eclectus

I use a Road Morph. The pressures read in segments. I have Innovations inflator, I have no idea what the pressures are, you have no idea what their pressures are. If you use Innovations without guage, you are before Neanderthaal.

Yellowbeard

Because then it's the liquid portion that's flowing out of the cartridge, instead of the gas. When it expands enough heat is absorbed from the nozzle area to freeze the liquid as it flows out.

achoo

More precisely, the expansion of the CO2 is effectively adiabatic (without transfer of heat because it happens fast enough), so the gas itself cools down as it expands on its way out of the cartridge. And it can get cold enough to freeze up.

achoo

If you've been paying attention to your tires when you ride, you can get pretty darn close to proper inflation pressure just by feel.

No gauge needed.

StephenH

"When it expands enough heat is absorbed from the nozzle area to freeze the liquid as it flows out."

I think some of the liquid vaporizes which cools the remaining liquid off until it freezes, it doesn't need to have heat absorbed from outside.

superdex

um, why?

njkayaker

Google is a quick (and better) source of an answer to this.

https://www.justanswer.com/questions/...-co2-cartridge

Phantoj

So why wouldn't this happen if you held the cartridge right-side-up?

Quel

We are confusing chemistry here now. If you hold the cartridge right side up, it will still freeze. The gas expanding from a high to a low pressure causes a temperature change (joule-thompson effect).

If you hold it upside down, that same effect occurs. But if it's upside down, the liquid CO2 comes through the valve (because it's more dense than gaseous CO2) and flows to the lowest point.

Phantoj

So you're saying if I discharge a CO2 cartridge with it held upright, "it will still freeze" (solid CO2 will still be formed.) Does this solid CO2 stay inside the cartridge, or does it get blown out?

If I discharge an upside-down CO2 cartridge, will I make more solid CO2 than if I discharge an upright cartridge?

ElJamoquio

All things being theoretical, they will have the same amount of solid CO2 (assuming there's any solid CO2 at all). The one held upside down will spit more of it out.

All things being theoretical, of course.

Quel

Sorry, I chose a poor word when I said "freeze". I was using "freeze" to mean "get damn cold", instead of actually changing the form of matter.

If you discharge a CO2 cartridge upright, the temperature will get lower...enough to get your hands cold and probably below water's freezing point...but not below CO2's freezing point.

mollusk

Extra credit question: What about if it above 88 F?

achoo

It probably does, but the frozen CO2 doesn't fall out.

Why don't you look into one right as it's opened so we can be sure?

Phantoj

OK, so Quel says the cartridge doesn't make solid CO2 (dry ice) if discharged upright (it will "get damn cold", though). What about if it's discharged upside-down?

achoo and ElJamoquio say that the CO2 cartridge will make a roughly equal amount of dry ice regardless of orientation, but the dry ice remains hidden inside an upright cartridge. (Although ElJ hedges that this is a theoretical answer.)

Is that the correct scorecard so far?

Me personally, I don't know what happens, but I have found the explanations, up to this point, to be unsatisfactory.

Quel

The CO2 inside the canister is liquid, so when upside-down, some of that will flow out (gravity) before it can turn into a gas. CO2 doesn't turn solid at room temperature until you get to very very extreme pressures, much much higher than you can get with these containers (much higher than large scale chemical reactors run for that matter).

Yellowbeard

The thing about discharging it upright is that the whole surface of the cartridge can absorb heat from its surroundings, so the cartridge and it's contents get cold enough to freeze water vapour on the surface, but not cold enough to freeze the CO2. When it's upside-down the liquid is being forced out by the pressure in the cartridge at the same time it's expanding. There's less warmth available then.

mollusk

I think that I will use this question as a lecture example next time I teach introductory thermo.

Phantoj

So you're saying CO2 canisters can't make dry ice, no matter what orientation they are discharged in.