12v Compressor, no tank: Open chuck vs...? (1 Viewer)

[woytovich]

I was looking at plumbing my ExtremeAire 12v compressor for use without a tank.

Since there will be no pressure switch I would normally need to use an "open" chuck (or extreme caution!) to keep the compressor from bursting the hose or burning itself up if it was running without a tire (or something) connected to a standard "closed" chuck to allow the air to flow.

I was considering an alternative and wanted to pass it by you all for comment:

I was thinking of adding a blow-off safety valve on a 2 port manifold (with the 2nd port being the air hose). If I use a valve rated at, say, 90psi (or lower if I'm just using this for tires) then if I was using a standard chuck without something attached the valve would blow off pressure if/when the pressure at the manifold builds...

Would this work or will the pressure that the blow-off valve sees be significantly higher than the pressure I'm shooting for in the tire (say 40psi) and blow the valve prematurely?

Does that make sense?

I can test this unless someone has some real-world info to share...

Thanks,
mark

 

[CarterTheFarter]

I don't have an on board compressor yet but I do deal with a bunch of mako and Bauer compressors at work.

From the final stage on the compressor to the tire should be the same psi as long as your chuck isnt holding back air. Most of our reliefs are set to 10% over normal operating pressure. So for scuba we fill our jugs to 3000 and the relief is set to 3300. We have automatic shut offs at 3000 but just in case that relief is there. We also take into account for higher pressure from heat but I don't think you will have a problem with heat in a LP system.

Find out the weakest link in the system. Normally the air hose and as long as you don't exceed the max psi for that you should be good to go.

Carter

 

[CarterTheFarter]

You can also put a manual button or turn style valve right before a closed chuck and open it when the chucks holding back air and close it when your jamming. Kinda ghetto but it would work.

Carter

 

[woytovich]

You can also put a manual button or turn style valve right before a closed chuck and open it when the chucks holding back air and close it when your jamming. Kinda ghetto but it would work.

Carter

Thanks for the insight.

I would want some sort of "auto" relief valve... I will have a power switch on the compressor - I could just use that if I want manual control. I am thinking more about those in between times: switching from one tire to the next or pulling off the chuck to check tire pressure. I'll probably kill the compressor in those cases most of the time but I don't want a disaster to occur if I skip that step - like if I'm 20 feet away from the compressor at the end of the air hose...

 

[CarterTheFarter]

I wonder if extreme outback has some kind of automatic shut off. That way your compressor wouldn't be running while you switch to the next tire or whatever. I'd give them a call and see what they can do for you or advice they can give.

Carter

 

[woytovich]

EVENTUALLY I will be adding this compressor to a tank system. At that point I'll have a pressure switch on the tank. In the mean time I want to rig this up for use without the tank...

Mark

 

[Betarocker]

Add a Tee between the leader hose and the compressor (or preferably the check valve it has one). Bush it down to 1/8"FNPT and install a 100-145psipressure switch. Get a palstic weathertight junction box and mount it to the compressor. Wire properly with relay.

As soon as the chuck is mounted on a valve stem, the pressure in the line will drop to below 100psi and turn on the compressor. As soon as the chuck is removes, the compressor will pump a few times and the pressure in the line will quickly climb to 145psi and shut down. Simple redneckery.

 

[woytovich]

I was thinking that maybe a pressure switch right there at the compressor output would get "fooled" by the bursts of pressure each time the compressor discharged and want to cut the power... then, as the pressure drops the switch will turn the compressor back on - resulting in a rapid on/off/on/off that would be a "bad thing" for the compressor motor.

 

[Betarocker]

Though I haven't tested your theory, I think it is unfounded. The pressure in the system increases equally. It shouldn't matter if the pressure switch is in the supply line or in the tank.

 

[woytovich]

The pressure in the system increases equally. It shouldn't matter if the pressure switch is in the supply line or in the tank.

Not sure if I agree... but it is worth testing. I guess any delay that the pressure switch might have in sensing an increase would impact this as well. I do believe that the tank might act as a buffer for the increase in pressure of each "push" from the compressor - smoothing it out somewhat.

I hope someone that KNOWS chimes in...

 

[CarterTheFarter]

I think betarocker may be right. I think it is at least worth a try. From my experience the pressure slowly builds in a system. There shouldn't be a burst of pressure being sent down the hose.

 

[ToyRoverlander]

I have the pressure switch right at the outlet of the compressor on a T-piece. I don't use a tank.
I flick the switch on the dash, compressor runs...fills the line and shuts off. As soon as I open the chuck to inflate a tire the compressor starts running again. When I close the chuck it takes a couple of seconds for the compressor to fill the line to max pressure before it automatically shuts off again.
Works like a charm.

 

[woytovich]

I have the pressure switch right at the outlet of the compressor on a T-piece. I don't use a tank.
I flick the switch on the dash, compressor runs...fills the line and shuts off. As soon as I open the chuck to inflate a tire the compressor starts running again. When I close the chuck it takes a couple of seconds for the compressor to fill the line to max pressure before it automatically shuts off again.
Works like a charm.

Thanks.. I have been stalled on the project so this is good to know before I get back to it...

 

[ToyRoverlander]

No worries, glad to help.

 

[titanpat57]

I have the pressure switch right at the outlet of the compressor on a T-piece. I don't use a tank.
I flick the switch on the dash, compressor runs...fills the line and shuts off. As soon as I open the chuck to inflate a tire the compressor starts running again. When I close the chuck it takes a couple of seconds for the compressor to fill the line to max pressure before it automatically shuts off again.
Works like a charm.

Do you have a picture and would you mind posting it?

Thank you,

 

[ToyRoverlander]

I can try to take a picture of it today but the compressor is quite well hidden inside a wheelwell compartment together with two inverters.

 

[rusty_tlc]

I have the pressure switch right at the outlet of the compressor on a T-piece. I don't use a tank.
I flick the switch on the dash, compressor runs...fills the line and shuts off. As soon as I open the chuck to inflate a tire the compressor starts running again. When I close the chuck it takes a couple of seconds for the compressor to fill the line to max pressure before it automatically shuts off again.
Works like a charm.

My buddy's Viair is set up the same way, works fine.

 

[ToyRoverlander]

Viair is what I've used as well. Except the compressor, that's a different make.

 

[ToyRoverlander]

Didnt get round to take pics today. Will take some tomorrow

 

[ToyRoverlander]