[quote]
QUOTE: Originally posted by A-Centauri
Isn’t dry ice CO2 in it’s solid form? [;)]
Mike
Hmmm… Yes and no. You see, CO2 is characterized by a pretty weird behaviour under the aforementioned pressure conditions. Practically, it can be in gaseous - liquid - solid form ALL AT THE SAME TIME, depending on the temperature, pressure fluctuations and/or other chaotic factors.
If it was a liquid (in trivial terms) it would shift its position inside the tank. However, if you hold a CO2 tank on its sides and tilt from left to right you’ll notice that nothing seems to move inside the CO2 tank the way a “normal” liquid would. This is mostly because CO2’s form in the tank is very close to ice, since CO2 changes its form by sublimation, thus it has no true liquid state. Sublimation is the change from solid to gaseous phase without transition through the liquid. As far as CO2 is concerned, there’s also a 4th phase of matter called supercriticality. This phase exists above the critical temperature and pressure of the compound. It is sometimes called a supercritical “fluid”. The “fluid” would occupy all of the space in the container and hence it would not slosh around, ie. there will be only a single phase in the container if it is above the supercritical temperature and pressure.
Theoretically, liquid CO2 does exist, however, depending on the pressure, adiabatic expansion causes the cooling effect that changes it into dry ice…
Holy cow… is this all waaaaaay off topic, or what? Hey, is there a chemist in the house? [:D]
Man George! [:D]
I only live 25 miles from the famous Lawrence Livermore Lab.
Maybe I could contact them in regards to this. [:D] Haha
Thanks for the answer, it was informative. [:)]
Mike
ok, ok, back to the tank now, im curious, i finally finished putting my regulator on and you all were right it lasted me about 15 minutees. if i drilled the pressure relaese hole in the adapter that i purchased from badger would the allow me to have a electric compressor filling the tank non-stop?
Drilling the pressure release hole doesn’t sound safe. I’m not sure of your set up but if there is a threaded fitting in the tank, you can hook the regulator and compressor to a ‘tee’ threaded into the tank. Then the tank acts as a surge vessel allowing regulated air to your airbrush while any air from the compressor that isn’t used is stored in the tank. If the compressor doesn’t have a pressure shut off switch, you will need to monitor the tank pressure to prevent overfilling. I have a ‘tee’ on my tank with a pressure guage on either side of the regulator to monitor tank pressure and airbrush pressure. I hope this helps. Thanks for not bringing CO2 back up…whew what a science lesson we got with that!
thx holley, i think that im going to try that, what amount of psi needs to be put out by the compressor to successfully fill the tank, will 125 psi or above work?
I agree with Holley. Don’t ever try to drill a hole in the tank unless you are prepared (as well as properly equipped) to weld a threaded fitting on it. Otherwise, consider the “tee” method to be your best bet. I also think fitting an automatic (properly regulated) shutdown switch to be an absolute necessity in any case. Turning the compressor on and off manually is simply a no-go, if you want to play it safe. You should also make sure that you never exceed 110 - 120 psi of pressure in the tank. Don’t worry about “filling” the tank. At 8 atm (110 psi) the tank will be “filled” with air 8 times its nominal capacity…
Best of luck…
badger tells you to drilla hole in the adapter for your air hose from 1/4 adapter for compressors that do not regulate themselves that will build up to much exsess pressure, but im not sure if it will work because this adapter is after my regulator and it is meant for non-tank, “made for airbrushing” compressors, hey, how much does this automatic shut off switch go for and where can i get one?
As long as you have a regulator, your compressor only needs to put up more pressure than you have it regulated down to. The excess will go into the tank. The tank also acts as a surge surpressor smoothing out the air flow so you dont get that ‘tat tat tat tat’ type of spray pattern. I have used mine with no pressure shut off switch, but I do have a pressure guage on the tank to tell tank psi. It probably would be a safer idea to install a pressure shut off switch, which you may could find from an industrial supply house or maybe even an auto paint distributor,