Air Compressor Drainage

[scotw]

Ok, I made a mistake. I won't do it again. I have an air compressor that has not been drained in a very long time. I won't say who was president the last time it was drained.

Is it safe to use? Do tanks explode or just develop small air leaks?

Thanks for any advise, and I promise it won't happen again.

Scott

 

[1320stang]

Should just leak, but my 10 gal. air tank has an expiration date on it, so I'm not sure.

Is it leaking?

 

[stuckinohio]

I don't have much advice on the tanks safety, but am curious how much water came out and what it looked like. One of the shops I worked at forgot about draining the tank for a long time too. Where the compressor was located, it was really hard to access the drain. The only thing I could find to catch the water was the lid of a large trash can. We counted how many lids the tank filled in the process of draining it, then measured how much water the lid held when we were done. I think it came to aound 75 gallons of water. I can't remember how big the tank was, but it was at least 200 gallons.

 

[Steve in Mi]

Yes air tanks do sometimes explode!

Any time the condition of an air receiver is in question the best thing you can do to ensure safety with its continued use is to have it hydrostatically tested at 2X or 2.5X the operating pressure. The older the tank the more frequent the hydro test should be performed.

 

[Lloydthumper]

I would say the tank would rupture in the spot it rusted through but not explode. The air inside is only putting excessive force on the weakest part at this point. If the pressure is exceded to the point of an explosion someone didn't have a pop off valve on the tank or it was stopped up or to small.

 

[engnerdan]

This is what happens, a pressure vessel will always split along the cylinders axis unless there is some specail conditions.

-Dan

 

[D KRAGER]

While we are on this subject..... Why do they make it so difficult to drain the tank. They want it drained daily, but they make it where you have to reach all the way under to drain it. I have a compressor shack out back, not easy to drain the tank. So I'm gonna rig it up with a 1/4" nylon air line running to the bottom of the tank and mount a remote valve inside the garage to drain the tank. This way maybe it will get drained daily.....

 

[1320stang]

D KRAGER, get an autodrain.

 

[D KRAGER]

What's the best one to get? And where? I see them at Harbor freight, but I've heard they are junk.....

 

[ricleh]

Ingersoll-Rand sells them. Check http://air.ingersollrand.com




Rick

 

[indyracer]

Get one off ebay. That is how I got two of them. It is awesome to not have to drain my tank manually.

http://search.ebay.com/search/search.dll?from=R40&_trksid=m37&satitle=electronic+drain+valve&category0=

 

[Rickochet]

While we are on this subject..... Why do they make it so difficult to drain the tank. They want it drained daily, but they make it where you have to reach all the way under to drain it. I have a compressor shack out back, not easy to drain the tank. So I'm gonna rig it up with a 1/4" nylon air line running to the bottom of the tank and mount a remote valve inside the garage to drain the tank. This way maybe it will get drained daily.....

The reason why they don't make it easy to drain is becasue they want to sell you a new compressor when yours is rusted out because you didn't drain it very often because they didn't make it easy to drain because they want to sell lots of compressors..... It's just a vicious cycle. Make it easy to drain so you can end their cycle!

 

[Junkman]

Get one off ebay. That is how I got two of them. It is awesome to not have to drain my tank manually.

http://search.ebay.com/search/search.dll?from=R40&_trksid=m37&satitle=electronic+drain+valve&category0=

I keep draining my tank manually, and when I last saw the IR drains on ebay, new ones were selling in the $65 range. I can't believe the jump in price in the past 6 months!!!

 

[PoorOwner]

I looked at Ebay for the IR and they go over $100 !!!!
I am going to make my own with a 300 PSI solenoid and a timer. I can make it drain every wednesday or whatever days and at the time I want.. cost will be around $40 + fittings.

 

[z28toz06]

I looked at Ebay for the IR and they go over $100 !!!!
I am going to make my own with a 300 PSI solenoid and a timer. I can make it drain every wednesday or whatever days and at the time I want.. cost will be around $40 + fittings.

post pics and part list when u are done!

 

[russlaferrera]

I don't understand why it's so hand not to drain the compressor tank. There is a 1/4 npt fitting under the tank. Put an ell fitting, 12" piece of pipe , valve and your done. Want to drain it to somewhere? Add tubing.

IMO if you own a compressor. You should posses the knowledge to perform this simple plumbing feat.

 

[6768rogues]

My father had a tank upstairs in his shop and it exploded. It was a vertical tank and the entire bottom except for an inch or so came off; like it hinged open. The damage was: broke a roof truss and lifted the corner of the roof off the building, blew a hole in the loft floor, put a 12 foot long crack in the concrete block wall, knocked a sink off the wall and knocked a door off its hinges. He was under it and happened to step away just before it blew. The neighbors, over 500 feet away, heard it inside their house and came running.
I would not use a tank that is questionable. 100# of pressure is 100 pounds per square inch. Add up how many square inches your tank measures and think about the total force that is being released suddenly. Ka-BOOM!

 

[russlaferrera]

6768roques, Glad he is OK. Do you remember any more on the incident? How hold was the tank, did he buy it new, was it maintained?

 

[6768rogues]

It was a tank that my brother put in the compressed air system before he moved to Florida. It was in place for probably about 15 years, forgotten until the day it blew. My father had a few bruises from debris that hit the back of his legs. I don't know the origin of the tank but it was probably used when it went in. It taught me to respect the potential of a compressed air container.

 

[Lloydthumper]

I understand the fact that a tank can weaken and also rust through. The part I am not understanding about these incidents is why the sudden total failure of the tank. I under stand a hole rusting through. But I have never not saying it hasn't happened seen a tank explode of any kind with out an impact or sudden change in temperature or excessive pressure it wasn't rated for etc. Very few things rust at an even rate usually a hole will develope in one spot and then what you have is a leak not an explosion. I would really like to know the details on the ruptures.

 

[Charles (in GA)]

I saw this discussed on a tractor forum also. One forum member related a story of his compressor exploding one day while he was gone. He came home to find a hole in the roof and a big mess. Apparently the bottom weld encircling the tank (vertical tank) gave way, possibly aided by a ring of rust from standing water inside. Yes it happens, but not very often. I suspect a compressor has to be pretty old and ill maintained to get in this condition.

Charles

 

[jay50]

This is what happens, a pressure vessel will always split along the cylinders axis unless there is some specail conditions.

-Dan

Dayum; what a mess.
Well, I guess my next project will be building some type of heavy duty cage to surround my air tank to contain all the scraphnel when it finally decides to let go.

anyone got some plans and a parts list?...

 

[Steve in Mi]

The part I am not understanding about these incidents is why the sudden total failure of the tank.

If you really want to study the subject further I'd suggest looking into such things as metal fatigue and expansion/contraction cycling of pressure vessels. A good book on strength of materials and an ASME publication on air receiver design could be a starting point.

 

[Phatsub]

I've seen some pics in TGJ from members using PVC and ball valves for manual draining.
I'd like to get details on those to build one for myself.

 

[jeepgod]

i did what was mentioned above.. put an L fitting in the bottom.. 6" of pipe... and a ball valve... with a barb on it with 3' of hose attached... the hose reaches outside to the yard.. and i just turn the valve to on... cost me about 10 bucks.. and works like a champ..

if you cant remember to drain your tank every so often.. then you shouldn't own a compressor...

only folks that i think would need something automatic would be a business or someone that really uses one a lot... but for the most of us.. an easy to access and use manual should be good enough..

 

[PAToyota]

only folks that i think would need something automatic would be a business or someone that really uses one a lot... but for the most of us.. an easy to access and use manual should be good enough..

I guess the one question is whether you leave the tank pressurized when you leave for the day. I shut off power to the compressor and close a ball valve to the rest of the piping run, but keep the tank pressurized. I have an auto-drain for that reason. It drains the moisture until I get back out there again.

 

[jeepgod]

yes i leave it pressurized.. i just shut off the air to my lines and drain my lines plus remove power from the compressor when i am done in the garage... but i don't use mine every day.. or even every weekend.. maybe every other weekend.. i drain it once a month.. not much water comes out..

like i said.. if you use it a lot.. every weekend.. and most of the day and its cycling on and off.. then something automatic would be better.. but i think for the majority of us do it yourselfers' you dont really need to spend a 100 bucks on that..

 

[e-tek]

My Dad had a bodyhsop and I've worked in a few body and mech shops when younger - all of them depressured and drained the tank at the end of everyday. That's what I do in my home shop - every night I'm done, I open the valve and let it drain out. I'm always surprised to see how much water (yellow water!) comes out after one day of use.

 

[engnerdan]

I understand the fact that a tank can weaken and also rust through. The part I am not understanding about these incidents is why the sudden total failure of the tank. I under stand a hole rusting through. But I have never not saying it hasn't happened seen a tank explode of any kind with out an impact or sudden change in temperature or excessive pressure it wasn't rated for etc. Very few things rust at an even rate usually a hole will develope in one spot and then what you have is a leak not an explosion. I would really like to know the details on the ruptures.

I don't think it requires a near complete rusting through like you are thinking, all it takes is a weak spot that is thinner then the rest and spread. Just the cycling of the cut in and cut out pressures inside the tank can be the stress needed to initiate it, the tank swells as the pressure goes up inside.

-Dan

 

[stricht8]

I have a Craftsman compressor and the manual says drain daily after each use. The only way to do this is to depressurize it and that is what I have to do. I have to admit I cringe a little for the last few seconds the tank needs to pressure up to the max 150 psi. I wonder if a larger tank is more prone to rupturing?

 

[Lloydthumper]

I have a Craftsman compressor and the manual says drain daily after each use. The only way to do this is to depressurize it and that is what I have to do. I have to admit I cringe a little for the last few seconds the tank needs to pressure up to the max 150 psi. I wonder if a larger tank is more prone to rupturing?

I hope not I have a 60gal and a 100 gal tank.

 

[tolken4]

i have always wondered the exact proper procedure... Use it during the day and then....

1. Open valve to drain.
2. close valve
3. or leave valve open until next use?

 

[stricht8]

I've wondered the same thing. First I was keeping valve open, then I started closing it after drainage. I would also like to know the proper technique.

i have always wondered the exact proper procedure... Use it during the day and then....

1. Open valve to drain.
2. close valve
3. or leave valve open until next use?

 

[PAToyota]

I've always kept mine pressurized with the auto-drain on.

 

[SteveU]

I keep mine pressurized and blow off water with the auto drain while I am using it and after I am done then unplug the auto drain and shut the ball valve off at the tank. I have read on another forum that it isn't good for the tank to constantly pressurize and depressurize it not only that, I don't want to have to wait for the 80 gal tank to pressurize up to 140 psi each time I want to air up a tire, ball, or blow something off.

 

[tolken4]

??? So, should I be just letting the water out then closing it tight again while still pressurized?

 

[russlaferrera]

I have a Craftsman compressor and the manual says drain daily after each use. The only way to do this is to depressurize it and that is what I have to do. I have to admit I cringe a little for the last few seconds the tank needs to pressure up to the max 150 psi. I wonder if a larger tank is more prone to rupturing?

Why do you have to relieve the air pressure to drain the water out?

 

[BrianAltenhofel]

On my tank, when you open the petcock on the bottom, the tank gets almost fully depressurized before any water starts to come out. I've been meaning to plumb a line so I don't have to get on the floor to drain it, just too many other projects.

 

[larry4406]

I leave my tank pressurized all the time. When I feel like it, I manually open the bottom drain, air blows the water out, when the water stops coming, shut the valve. The valve is on the end of a ****** with a street 90 out of the bottom of the tank. If you have to fully depressurize a tank to get some water out, I would say you don't have enough water in the tank to begin with to even worry about. Not real hard.