Compressor spitting out oil....

[Will Blick]

Arggggg.... this is a classic case of .....if it aint broke, don't fix it.

I have a relatively new CH air compressor, 60 gal upright tank. About 100 hours on it.... I noticed there was NO filter on the air intake.... wanted to prevent wood dust from entering, so I added a CH air intake filter. Dealer said it was designed for this unit. I wondered why it did not ship with the unit? After adding this filter, and not paying attention to the unit as it was running unattended for a few days (slow use project), the unit is spitting oil out the air discharge. The reason has to be, the air filter was too restrictive, forcing intake air through the oil reservoir cap, which I could feel slight intake. Why did this occur? Are some air compressors designed NOT to filter incoming air? The filter was quite restrictive, looked like a HEPA type pleated filter...

How do I get the oil out of the tank??

TYIA

[Terry Beadle]

Use the spitter valve at the bottom of the tank, open until expurt is just air.

Recommend a oil catcher on the output side of the tank. You unit is relatively new so the rings are still seating to the cylinder(s).
water and oil filter example : http://www.amazon.com/Parker-Evolution-Compressed-Element-Particulate/dp/B004O0U6X8/ref=sr_1_1?ie=UTF8&qid=1335634254&sr=8-1

That one is a bit pricy but it should give you good results.

[Will Blick]

Thx Terry....forgot to mention, I did have oil capture filter on top, of course it was full of water and oil....
I did drain the tank.... still disperses oil...
my concern is, the oil is lined all over the interior of the tank, and the compressed air will always discharge oil in the air?

So I guess this system must run with NO air intake filter on it?

[Kevin W Johnson]

Will,

What is the model number of the pump? Mines VT470000xx (can't remember the letters on the end). I have a 60gal Husky (HD) that is a CH rebadge. Mine came with a filter and I have no issues other than the filter housing was so poorly made air leaked around the filter until I corrected that.

[Will Blick]

Kevin, is your filter pleated, like a Hepa, or a sponge type filter? The problem was obvious.... too much resistance from the filter forced air intake through oil port, which has an air releif if the air intake can not get enough air. I am thinking the filter they sent simply had too much resistance.... is yours sponge type?

[Kevin W Johnson]

Its a pleated filter.

The vents in the beather are mainly there to relieve any positive/negative pressue in the crankcase as the pistons move up and down. You really shouldn't be getting that kind of blow by at the rings.

Can you post a picture of the filter?

[Charles Lent]

During compressor operation there is a short and slight puff back or reverse flow of air out of the air intake as the compressor cylinders change direction from drawing in air to compressing it. This is due to the time that it takes for the reed valves to close. This air will contain tiny droplets of oil. A pleated paper filter will plug up very rapidly when oil gets on it as the oil causes the fibers in the filter media to swell. You should use a foam filter if you want to install a filter. They will not plug up from oil vapor and the traces of oil on them will actually make them work better.

Charley

[Rick Christopherson]

At first glance you will think the line is spewing a ton of oil, but it is actually mostly water. The air inside your tank has become super saturated. Instead of just opening the drain until liquid water stops coming out, completely drain the tank. You need to do this every once in a while if the compressor runs frequently or in higher humidity. Draining the liquid-only will help, but you still periodically need to drain everything.

[Will Blick]

I will try to post a pix when I get back to shop..... I think this thread confirms my suspicions.... with NO filter on incoming air, the compressor operated flawless, as it was not choking for air. I think Charley has the right concept here, except this NEW filter did not plug from oil, it simply was too restrictive for this air intake, hence why I feel the oil cap (with air relief holes for balance) started sucking in air.... I found a web site that suggests starving air intake is one of the reasons you get oil in the tank.

Rick, you are correct, its mostly water, but in the oil/water filter, you could see a nice thick layer of oil on top of the water. The ratio was prob. 95% water, 5% oil, but that amount of oil in air makes it smell and feel very oily. Yes, I do drain the tank regularly, however, small oil droplets will prob. coat the walls of the tank and will be hard to get rid of... time will tell.... and lesson learned. These low cost 60 gal compressors should only use what is designed to be on them. My guess is, the dealer who sold me this filter, which fits perfect, must be for a different CH unit, as they prob. change them every few years. A foam filter would prob. be good enough...but at this point, I think I will not use a filter at all, as I prefer to prevent this mess from ever happening again. Dust in shop is not overwhelming.

[Jerry Bruette]

Will

I've been thinking about your compressor problem since you posted. I'm not so sure your problem is the intake filter. The crankcase vent is to equalize the pressure in the oil reservoir as the piston moves up and down. It's natural to feel some air moving in and out as the compressor is operating, that's and indication that the vent is not plugged. If the vent would be plugged you'd build pressure in the crankcase and that could force excessive oil int the cylinder.


When the piston moves down in the cylinder the discharge reed valve would close, the intake reed valve would open and allow air into the cylinder and some air should escape from the crankcase vent. When the piston moves up in the cylinder the intake reed valve would close and the discharge reed valve would open allowing the air to escape from the cylinder into the tank. At the same time you should feel some air being sucked into the crankcase vent.

Some of the oil will leak past the piston rings and be discharged into the tank, this is a normal occurance. This oil should be bled out of the tank with the blow down valve on the tank, the water will be discharged at the same time.

A plugged or severly restricted intake wouldn't cause oil to be sucked from the crankcase into the cylinder but it may cause your compressor to run hot and possibly kick out from temperature or amperage overload.

Jerry

[Will Blick]

Hi Jerry.... a few more bits, yes, compressor was running hotter than I ever recall... and what made me convinced it was the air intake filter, is because the compressor NEVER had this problem till I installed the air intake filter.... the unit came with NO air intake filter.

When I removed the intake filter with the unit running, I felt the incoming air through the air relief in the oil cap STOP....or at least I could not detect it any longer.... With the air intake filter on, air was hissin through the oil cap air relief holes, so it seemed obvious to me, the fast moving air through the oil reservoir was pulling the oil vapor into the tank.

But I have been fooled before by what "appears to be obvious" ......what do you think now?

As for the volume of oil....when I sprayed the compressed air on my hand, it left a noticeable oil residue, which I never experienced with any compressor before... so a significant amount...