Air tanks and where to put them

[oldmacdonald]

I'm not sure but I think you'd get away with the ORO placement in a shorty.

[Mud'N'Guts]

I already have an air lying around somewhere. I'll check whether it will fit the ORO system though, it would be easier having it outside of the vehicle rather than using the little space i have in the back there.

[Matty ducati]

Has anyone tried a rattle gun on a setup like these, how long does it take to kill the pressure?

[Mud'N'Guts]

Depends what PSI you run the compressor at and what volume tank and also what PSI the rattle gun needs. So you would need one of those things that keeps the PSI limited when leaving the tank (regulator). The higher the PSI you run the tank, the longer it would last running anything with a lower psi (higher volume helps too).

If you find the tank you want and know what PSI you are going to run it at you could do some math to find out how long you have.

[Grahame]

Originally Posted by Matty ducati

Has anyone tried a rattle gun on a setup like these, how long does it take to kill the pressure?

I haven't actually tried it as I don't have a tank (which is pretty slack for someone that works for a company that makes compressors and air tools). A small to medium rattle gun uses about 120 litre/minute and the ARB compressor is rated to about 70 litre/minute (this flow drops to about 60 when it's up near its rated pressure). With a small size tank a gun should deplete it pretty quickly and then the compressor would be on the back foot to keep up. Air tools are best run at 90 psi at the tool inlet. The optimal tank size is 10% - 15% of pump capacity, so for an ARB compressor (the large one) 10 litres is about right.

[oldmacdonald]

Grahame, you probably know more about this than anyone else on here, mind if I ask some more questions about how to set it up?

I plan to run a braided hose from the compressor to the tank (if not the whole way, at least the first 12" or so) and put a check valve on the "in" port of the tank, perhaps something like this:

It looks a bit like an unloader valve as well to me, you reckon it is? In any case, is the tank the best place to put the check valve or should I put it closer to the compressor?

[Grahame]

Originally Posted by oldmacdonald

Grahame, you probably know more about this than anyone else on here, mind if I ask some more questions about how to set it up?

I plan to run a braided hose from the compressor to the tank (if not the whole way, at least the first 12" or so) and put a check valve on the "in" port of the tank, perhaps something like this:

It looks a bit like an unloader valve as well to me, you reckon it is? In any case, is the tank the best place to put the check valve or should I put it closer to the compressor?

The function of the check valve is to stop the compressor rotating backwards under system pressure (industrial compressors can crash in less than 30 seconds if run backwards). The normal convention is to mount it as close to the compressor as possible. It will reduce the possibility of you bypassing it if you decide to plumb some extra lines in later on down the track. Your ARB compressor has a check valve built into it, probably a finger valve arrangement (I have one of these too but I've never pulled it apart). My compressor holds pressure pretty well and doesn't cycle very often if I forget to turn it off, so I probably wouldn't even bother with a check valve initially. If you find that you are losing pressure and and the compressor keeps turning off and on then a check valve may help. Bear in mind, one of the biggest killers of compressors is short cycling (frequent off and on) so anything you can do to prevent this will keep your investment living longer.

The ARB compressor is pretty well designed so if you keep the hose inside diameter the same as the ARB hose you shouldn't have flow and pressure problems.

That valve that you have shown is not an unloader, I think it's pretty much as described, just a check valve. The threaded connections use the convenience of the tank connections, hence the suggestion to mount on the tank. An unloader is used to relieve the pressure at the cylinder so that the compressor doesn't start against the system pressure.

Also, make sure your tank has a drain plug to empty the water out. If you intend to run air tools water in the air will corrode them pretty quick.