jackssmirkingrevenge wrote:
There's one that's been submitted for the
contest
Hmm, didn't see that. I know we had a discussion on said cannons, but I didn't see that anyone actually built one. Thanks Jack!
For Chaos, Spudthug is partially right. Compressing a gas (in our case, propane) in a closed container raises the temperature. However, an interesting point I also read is the fact that propane, when over 100C remains in a gaseous form. So, whether you achieve enough pressure to raise the temperature can only be tested.
I have here the source of my information:
Compressing a gas does affect its temperature, it actually INCREASES it, which is exactly the opposite of what you need if you are trying to liquify it. However, as I said before, providing the gas remains below its "critical temperature" (and each gas has its own) at some point the increased pressure will cause it to liquify.
In the case of propane this temperature is 97 degrees centigrade. This is obviously just below the "normal" boiling point of water (100 C). If propane has a temp of 100C it is impossible for it to be liquified no matter how much pressure you exert on it.
In the case of Oxygen, it has to be below MINUS 118.57 C (155 kelvin) to be a liquid.
In Gnomon's case, and he is quite right, of bottled gas and the "it is partially liquid: you can hear it sloshing around", applies only in what you might term "normal circumstances".
If Gnomon's gas bottle (let's assume it contains PROPANE) is submersed in a large tank of boiling water, the bottle and propane (liquid and gas) will start to rise in temperature. As the temperature rises more of the liquid turns to gas, but more gas in the closed bottle means higher pressure trying to stop the liquid becoming a gas. However the evaporating liquid slowly wins the battle. At some point the bottle and propane will reach 100 deg. C. When this happens there will be no liquid propane in the bottle, for although it will be under immense pressure, it will all have turned to gas. Infact if the gas bottle is not strong enough it will explode.
As well as the
URL to this discussion.
I hope this cleared it up.
"Never tell people how to do things. Tell them what to do and they will surprise you with their ingenuity." George S. Patton
propane for a pneumatic i have seen it on a couple of gun and was contemplating doing it with mine, because i dont have access to CO2 or HPA cylinder i was thinking of gas.
