OK, I finally figured out my compressor purchase and went with the Campbell Hausfield 60 gal upright - Lowes was even nice enough to part with it for $399 (gloat?)
The manual says that the tank should be drained daily. I'm wondering what people usually do with their large compressors... do you drain the tank every day, or just leave it pumped up so it's ready when you need it?
I installed a ball valve to replace the t-screw valve, 1/4 turn to full open. I let the valve leak just enough than I can hear it leak if all is quiet in the shop, this will keep the water drained. Because it takes less than 5 minutes for mine to go from empty to full when not in use I switch the compress of from auto to off. It takes about 3 days to fully drain all pressure.
I see no justification to subject the tank unnecessarily through inflation/deflation cycles. I'm reasonably certain that by 'draining' they mean the water from the bottom of the tank. Always a good habit. Buy a fitting which will allow you to attach a swaged line (think brake line from the auto parts store) and run it up along the side to the top of the tank where it is easily accessible. Install a ball valve (as per Leon) up there. If you want to get fancy, attach a small swan neck to the ball-valve so you can conveniently catch the water as it comes out.
Air pressure on my compressor is never fully released unless we are doing repairs or upgrades, etc.
We do, however have a ball valve and tube at the bottom of the compressor and at a few low points on the lines to remove moisture as well as a large FRL at any point where a tool is being run. We drain the water daily via a
10 second opening of the valve, etc.When we used to have super high volume needs (previous business) we set up an automatic timer that vented the valve at the bottom of the tank every hour for 2 seconds. We used to drain out a few gallons of water a day on the big compressors.
Folks in humid areas have highly efficient air dryers and possibly these purge systems to keep water out of air lines, etc. ...Especially medical and food grade systems.
But if you are talking air only? They must have a reason to do it, but I can't figure out what it is... I'd think pressurizing and depressurizing the system daily would cause unnecessary fluctuations and possibly damage long term - like bending a piece of metal back and forth slightly over and over again... Eventually, it fails / breaks.
Regards, Joe Agro, Jr. (800) 871-5022
01.908.542.0244 Automatic / Pneumatic Drills:
Pressure's not going to bother it, condensation however will rust it.
I used to work in a machine shop and I finally cracked the pet c*ck at the bottom of the tank so little that I had to use a plastic cup with water in it to get one or two bubbles every few seconds and just let it run like that M-F turned the compresser off Friday at 5 and resarted it on Monday at 7.
YMMV, Rich
Mike wrote: ...
They mean for moisture as others noted...
I know what they say but...
The 80(?) gal compressor here is 40+ yr old and has been left pressurized/on 24/7 and hasn't been drained but a time or two in its lifetime (and would add a "maybe" to that estimate).
It's reasonably dry here but not desert; I never see evidence of a great deal of moisture in the air. Don't use much volume which probably makes a difference; if it were in continuous use would probably be more need...daily surely seems excessively a-r to me unless a large volume is going through the compressor daily and/or it is very high RH area...
just to toss in $0.02, etc., ... :)
Let gravity do your work:
Take out the existing drain valve, add about three feet of large diameter air hose with appropriate fitting where drain valve was; put the drain valve on the end of the hose and run hose to convenient location.
Easier to drain, and the air hose, which doesn't rust, will now be holding a good deal of water that will not be standing in the tank.
I see no justification to subject the tank unnecessarily through inflation/deflation cycles. I'm reasonably certain that by 'draining' they mean the water from the bottom of the tank. Always a good habit. Buy a fitting which will allow you to attach a swaged line (think brake line from the auto parts store) and run it up along the side to the top of the tank where it is easily accessible. Install a ball valve (as per Leon) up there. If you want to get fancy, attach a small swan neck to the ball-valve so you can conveniently catch the water as it comes out.
I have kicked around the idea of making the valve a bit more accessible but I think you are going to have to have a high volume release to persuade water to go up a line and out. If you simply let the air trickle the water is probably not going to be completely drained once the bottom of the tank is empty, I suspect that the vertical line would retain water.
What do you mean by "drain"? If it's drain the condensate, yes, drain it daily. If you mean depressurize, then no, leave it pressurized for two reasons. First, it's simply a waste of energy to store it in the tank, then, for no good reason throw it away. Second, there is more fatigue damage to the metal tank from cyclic stresses than there is from static stress, and the deeper the stress cycles, the greater the damage.
IOW, it introduces more fatigue damage to the tank to go from 0 stress to maximum operating stress back to 0 stress than to leave the tank pressurized. Granted, the stress levels under normal pressures are small enough that you aren't likely to see a significant difference in tank life in either case. But, leaving the tank pressurized is less damaging than cyclic pressurization/depressurization.
Tom Veatch Wichita, KS USA
The air pressure will push any water up the line at tank-pressure until all the water is blown out. . I kept a 10 HP Webster drained like that for 20 years. The drain *is* at the bottom of the tank, the valve isn't. If you use an automotive brake line, it will clear all the water out. The vertical line will blow itself clear when you open the valve.
Rust is considerately reduced by the fact compressors are oil lubricated, so there is typically a water/oil mix in the tank. I used to worry about it, but my Craftsman compressor, which I inherited from my late FIL, never gave me an bit of trouble. When I sold it cuz of moving, it still worked great despite being almost 30 yrs old.
nb
I suspect the manual means "drain" in the sense that any accumulated water in the tank should be removed as opposed to dumping out all the compressed air. Just open the valve on the bottom of tank long enough to let out any water, and then close it up again. I try to do this on my compressor about once a day, but it winds up being more like once or twice a week when I remember.
Just drain any water out.
Replace drain petcock with a 1/2" ball valve and some pipe so that the ball valve can be kicked open or closed with your foot without bending over.
The final pipe is pointed towards the ground.
Drain tank on a weekly basis.
For me that was Sunday night.
Would kick the drain valve open and forget it.
When the compressor was started the next time, the drain valve would start "singing", reminding me to kick it shut.
Lew
Yes, that is true on a oil lubricated compressor that has oil leaking past the piston rings but a new compressor that is not leaking oil past the rings will rust prematurely if you do not drain the tank often in a humid environment.
With that in mind also not all compressor oil lubricated. I have has an old inherited 80 gal oiled compressor developed pin holes in the tank because of interior rust.
I installed one of the Harbor Freight "Automatic Compressor Drain Kit" on mine. It opens momentarily each time the compressor starts or stops.
Turn the bottom outlet on just a tiny bit. Do this at pressure.
You don't want to drain the tank, but have a nominal leak that blows water out the bottom.
My pump turns on every 6-7 hours when not using it. If a long time off, I unplug the pump.
Since doing that, my air has been much dryer and the dryers and active dryer does the rest.
Just what I am doing.
Mart> OK, I finally figured out my compressor purchase and went with the
Any oil lubed compressor will have some oil migration past the rings. It's almost impossible, or at least economically prohibitive, to attempt to reduce it in typical air tool grade equipment.
An example is SCUBA tank compressors, which are lubricated with a non-toxic soap solution and insanely expensive.
Nowhere did I state rust was entirely eliminated. I said it was reduced. Pay attention, please.
nb
I probably don't drain the moisture often enough. My tank remains pressurized most of the time. My theory is I always have air available, and I'm not running the machine needlessly.
It is a good idea to drain the moisture out fairly often because moisture can cause problems. Small problems include getting moisture into paint and tools. Big problems include rusting out the bottom of the tank around the drain valve. The tanks are pretty much un- repairable so then you buy a compressor (or part out a similar one).
RonB
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.