Compressor Sludge

There are no tank liners in the compressors I have worked with. If there was there would be a big note on the side to go with the price tag. Your experience might be different. I am familiar with oil. I am familiar with oil and water. There is no reason not to believe that an oil type compressor is not going to leak some oil which will of course come out with the water. Where I have lived we have days of 50-70% humidity. Water condenses like crazy inside the tanks. That same water comes shooting out of air hoses, spray guns, nailers, whatever the air tool. Heck I have even seen it spray like crazy from the 25 cent pump up your tires air compressors. You have to drain that tank if you are using the compressor. If you have a leaky drain valve or you purposely leave it leaking the amount of condensation inside is not that great. Yes I have left a small leak on a drain valve on a bigger compressor to reduce the need for the lazy staff to drain it. Even with draining the tank you still get water shooting out as the air cools with pressure drop. Yes the manual air dryer bowels will help a bit but if one is serous about dry air then you have to do cooling system first. Either the fancy air dryer that uses freon or its equivalent or water cooled dryers. Of course if you live in dry low humidity areas then you may not see much issues with condensation.

Of course, the lower the relative humidity the better, but to avoid tank condensation, it has to be quite low - almost desert conditions. Take my single stage compressor that runs a tank pressure of 135 psig as an example. Thats a compression ratio of (135 + 15)/15 = 10 to 1.

Without getting into a discourse on partial pressures, condensation will occur if the relative humidity is greater than the inverse of the pressure ratio. In my particular case, with a CR of 10/1, condensation will occur in the tank anytime the relative humidity of the intake air is greater than 1/10 or 10%. Folks that run a higher tank pressure will get condensation at even lower relative humidity.

Tom Veatch Wichita, KS USA