Beware of Old Aircompressors

[DaleB]

Regarding tank drains... for you guys with vertical tanks, are your drains dead center in the bottom of the tank or off to one side? Mine - a 20 gallon Puma from Northern tool, which appears to be identical to several others I have seen - has the drain offset several inches from the center of the tank bottom, meaning I have to lean it over some to get all the water out. I've wondered if this is normal or not... it's a real pain in the rump to tip it over to the side to drain it, especially since it's in a pretty snug spot. I'd put an automatic drain on it, but it wouldn't drain the last half cup or so of water anyway.

[ppilotmike]

... I bought one of these before my current setup. It was @#$%. The metal bits failed within a day, leaving me with a need to patch up my "on/off" pressure line and look for a better option. Since my tank is only 30 gals and I vent all the bleed noise outside (see previous post), it's no big deal to drain it completely at the end of each work session.

[Flyin'Bryan]

I have owned my Husky 30 gallon compressor from HD for about 5 years now. sadly I tend to leave the tank filled most of the time - which I never saw as a problem as long as I was actively working on the project and using the compressor. Probably need to rethink that a bit after reading several posts about failed compressors. I do drain it and change the oil seasonally.

The question that I have is what is supposed to be the 'average" useful life that one should expect to use compressors such as these before they should consider it having lived out its safe "useful life expectancy." I don't think my instructions mentioned anything about not using this compressor after a certain time period or number of cycles through the tank etc. So apparently we must simply guess as to when we think we should retire it.

So say you start seeing signs of some rust draining out of the bottom of the tank, which eventually clears up after it drains for a while. Is that a warning sign that you should replace the tank immediately? What if you drain it religously after each work session, and you see no signs of rust? Does that mean you can expect to keep using this compressor until the end of time? Will metal fatigue occur based on cycles of use (pressurized and depressurized) over a period of time? Will companies that sell pressurized vessels (welding suppliers, etc.) thoroughly inspect and/or recondition your compressor for you?

I am curious about how those that use compressors for commercial purposes handle this. Is there a strict maintenance or inspection schedule that is followed. Again, even if this is done, when do commercial operators decide that it has been used long enough and the time has finally come to replace it?

[rocketman1988]

I have an 80 gal vertical compressor and the drain is in the lowest part of the tank. I purchased an automatic drain, which is basically just a timer and solenoid valve, and plumbed it to the drain. Works great. Lets a 2 second burst out every hour. I felt that was a little too much so I put a digital timer on the drain timer. Now it purges 2 seconds every hour for 4 hours, three times a week.

Tank is bone dry...

[Rupester]

From the size of the tank and the handle that's visible, I have the very same compressor ... except mine is closer to 40 yrs old. I check it periodically for water and, to my surprise, never find any. It was always my assumption that a corroded tank would go "pfssssst" and leak away the pressure thru a pinhole. Looks like that assumption is not so good.

[boom3]

I'm guessing this is the make and model? This one has been passed around our airport and was recently given to me when someone saw me hand pumping up a tire. It actually works pretty good but I'm now thinking it could explode at any time.

Tick, tick, tick......

[ERushing]

Originally Posted by rocketman1988

I have an 80 gal vertical compressor and the drain is in the lowest part of the tank. I purchased an automatic drain, which is basically just a timer and solenoid valve, and plumbed it to the drain. Works great. Lets a 2 second burst out every hour. I felt that was a little too much so I put a digital timer on the drain timer. Now it purges 2 seconds every hour for 4 hours, three times a week.

Tank is bone dry...

I've been thinking about this modification myself. Which valve & digital timer did you end up using?

[aparchment]

You should be particularly concerned given your call sign of Boom

Originally Posted by boom3

I'm guessing this is the make and model? This one has been passed around our airport and was recently given to me when someone saw me hand pumping up a tire. It actually works pretty good but I'm now thinking it could explode at any time.

Tick, tick, tick......

[OLDSAM]

The proper way to periodically test a vessel such as this, if one is concerned about the age or corrosion or whatever, is a bit cumbersome but safe and effective. I speak of course of a hydrostatic test, with water. Fill the tank with water, you probably want to disconnect and plug/cap the inlet from the compressor discharge line first, then apply pressure with a small low volume, high pressure pump, to a pressure at least 50 psi higher than the air pressure that you plan to have at any time. Beauty of this method is of course that as soon as the tank starts to fail, the pressure is all gone, with no danger of shrapnel, unlike with air which expands rapidly to many times its initial volume, causing the extensive ripping apart of the tank and danger to nearby personnel. The use of air dryers on the intake will also reduce the amount of condensation that can form in the tank and extend the life expectancy. A real pita, but no loss of limbs, eyes, etc. Not to say that I do this, but I think about it occasionally.

[az_gila]

Originally Posted by OLDSAM

The proper way to periodically test a vessel such as this, if one is concerned about the age or corrosion or whatever, is a bit cumbersome but safe and effective. I speak of course of a hydrostatic test, with water. Fill the tank with water, you probably want to disconnect and plug/cap the inlet from the compressor discharge line first, then apply pressure with a small low volume, high pressure pump, to a pressure at least 50 psi higher than the air pressure that you plan to have at any time. Beauty of this method is of course that as soon as the tank starts to fail, the pressure is all gone, with no danger of shrapnel, unlike with air which expands rapidly to many times its initial volume, causing the extensive ripping apart of the tank and danger to nearby personnel. The use of air dryers on the intake will also reduce the amount of condensation that can form in the tank and extend the life expectancy. A real pita, but no loss of limbs, eyes, etc. Not to say that I do this, but I think about it occasionally.

How do you easily get 150 psi water at home?