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Why not compressed air bottle?

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Just another minion!
Just was thinking of running a 45ci compressed air bottle rather than an ARB compressor. I can use a nitrogen bottle for filling my tires (I have one for my shocks) and I use the small bottles for my paintball gun. Refills are readily available for both. Any thaughts on this guys?
Nitrogen will work for trail use, but will leak out quickly. Nitrogen is a thin gas and will leak through the rubber, but unlike Co2 it wont harm the rubber.
I'm not sure that's a great idea. The ARB solenoids may leak with Nitrogen and unlock when they shouldn't. Call ARB.
EVerything I've seen as of late shows that Co2 does not harm rubber...I may be wrong, but was under the impression that it was an old wives tale about it being harmful to rubber.
It's a bigger molecule than Nitrogen as well, so it's less likely to leak than nitrogen..."air" is mostly nitrogen...The Co2 Setups work great with the ARB's..I have several friend running it on their Rovers.
oooh Hippie crack!!

http://www.wessingtoncryogenics.com/CO2 Data Sheet.pdf

Co2 Isn't corrosive..."Carbon dioxide is the fourth most-abundant gas in the Earth's atmosphere. Animals exhale carbon dioxide and plants use photosynthesis to convert it to sugars and other forms of energy"....rubber all over the world is constantly exposed to Co2
but it does get COLD. My Powertank will get all frosty after airing up...in fact some of the Rover guys are using old school tanks with normal regulators...they actually freeze up. I can see how that would be a concern for a small valve with rubber o-rings...but remember, the pressure/flow required to run a locker is LOW...not a lot of evaporative cooling going on there...so not really likely that the orings will freeze and thaw repeatedly....
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The cooling effect observed with carbon dioxide is the result of the change of state. Once the vapor has warmed up, it follows ambient temperature. The primary advantage is a lot of gas can be carried in a small cylinder.

Unless the device "consumes" a lot of gas, the cooling effect does not really come into play. However the best way to use carbon dioxide as a pressurizing agent is to regulate it into a small vessel and from there into the device being operated.

Best to worse choices for pneumatics....(IMHO)....Nitrogen, Carbon Dioxide (if approved by manufacturer), "Scuba" air (dehydrated and filtered during pressurization), Noble gasses such as argon, the absolute worst is "compressor air" in which the air is used directly from the compressor unless the device being operated is designed to work with moisture and dirt in it's pressure supply.
I can run any of the gasses. I have tanks to run any of them. I was realy wondering about how much gas does it take to operate an ARB locker? Do I need large volumes of 'air' to operate it over a few days of off-roading? The advantages of running a small bottle (much smaller than a scuba tank) is space usage. As I mentioned I have nitrogen bottles that can run upward of 4500 psi and have as much as 72ci of capacity. Most of the time these nitrogen bottles are filled with dehydrated and filtered air.
MudDawg, is yours a voice from experience?
Once again THANKS TO ALL
well the benefit to Co2 would be that in a small volume of Co2 Liquid you get more gas than a comparable volume od "air"

That's why the 10 and 15 pound Powertanks and such work so well.
ARB's don't require too much air, just relatively high pressure (90psi). I think it's 90psi though, that's what I was told or read somewhere anyway. But, have you ever seen how big (or small depending on how you look at it) the ARB compression tank is on the compressor? It's teeny-weeny. That's it there with the big ARB logo decal on it, the silver can looking thing.


As long as you've got some manifold to connect the ARB solenoids to the "air" supply, you should be good to go. In fact, PowerTank actually makes a manifold kit designed so you can run your ARB's off a CO2 tank.

Thing is the ARB pump is aaround $190...and it's only good for the lockers....the duty cycle is sad...may as well put the $190 towrds eiother a good Co2 System or maybe a better pump (Quick Air 2 at the least...)
On the question of experience...I have been using pneumatically operated devices on my dragbikes for around 20 years or so...as many as 5 switching valves and 3 air cylinders, with a varying array of timers, pneumatic switches and regulators...in every case of failure other than fatigue, the cause has been corrosion and/or scoring from dirt particles...these failures were before i quit using on site air compressors and switched to bottled gas.

Also on switching valves with exhaust ports...add a filter to keep dirt from working it's way in that way.
Thanks Dawg. Hope you took no offence to me asking about you hands on with the CO2.
I think I will go with..........nitrogen.....or maybe dry air......okay I'll use......
My experience is mostly with paintball guns (but it's still ~14 years experience) and I agree with muddawg here. Nitrogen is great because it is inert and the pressure doesn't fluxuate nearly as much with temperature, but the main adantage of this is in high flow applications that are sensitive to pressure. The main disadvantage is that it is stored in a gaseous state and therefore at relatively high pressures in larger containers.

CO2 seems perfect for the ARBs which require very little volume of gas to operate at a fairly low pressure (since the tank will be upwards of 2000 psi). Since co2 is stored as a liquid, the tank can be smaller and the pressures are lower. However the pressure of co2 veries greatly with temperature and often times will even discharge liquid CO2 which can freeze and crack o-rings. The way around this is to mount the tank vertical or use an anti-siphon tube. As Muddag said, and exansion chamber, which can be nothing more than another very small tank, can be used to allow any liquid CO2 to expand before it reaches the device as well. I don't think this would be necessary for ARBs as the volume required is so low- and liquid co2 isnt going to hurt tires so fill away.
basalt51 said:
Nitrogen is great because it is inert and the pressure doesn't fluxuate nearly as much with temperature, ...

The former physics major in me has to disagree with you on this. All gasses are subject to the same law (and I'm sorry I've forgotten the name of the guy the law is named for ... Boyle's Law, perhaps?): P1V1/T1 = P2V2/T2

Which is Pressure x Volume / Temperature = Pressure x Volume / Temperature. This is valid for all gasses that do not change state to a liquid under compression, and it says that all gasses are equally subject to volumetric and/or pressure change as the temperature changes. Since we usually deal with gasses contained in a vessel of fixed volume, that means all gasses are equally subject to pressure changes in direct proportion to the temperature change.
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You are sharp Eagle....In any case if the pressure is regulated and is used through a 3 way switching valve everything should be ok...if the gas was captured in a sealed container, the pressure of carbon dioxide would have a larger swing over a wide range of temperature than nitrogen if both gasses were charted from the same baseline pressure and temperature......of further note, I would plumb a gauge into the supply line to the locker downstream of the switching valve...that way if the regulator goes south you can catch it before it overpressures the locker.

Of note...piston type regulators are more trouble free than diaphragm regulators and generally more compact. Either way be sure to add a jamb nut to the regulator adjuster so there will be no OOOPPS!! accidental pressure changes...Nitrous Oxide Systems (N.O.S.) makes a miniature billet regulator that is in my experience bulletproof...it is fixed at 160psi, but can be resprung/shimmed for different pressures. Any good welding supply house can supply the needed bottle fittings.
I guess I should have been more specific as I was comparing it to the CO2 which is stored as a gas and a liquid.