Water Separator Drainage

[UaVaj]

can someone explain to me why the drainage is - milky with browish strand (i think it this brown stuff is oil). help me understand what is happening inside the compressor to cause these type of drainage.

is this normal? has always been like this ever since new.

compressor is a maxair 35.

 

[rcontrera]

Quite normal. The air compressor actually sucks in oil vapor through a vent tube to the first stage. That oil will circulate through each of the compressor cylinders and will be kicked out in the condensate separator.

 

[UaVaj]

Quite normal. The air compressor actually sucks in oil vapor through a vent tube to the first stage. That oil will circulate through each of the compressor cylinders and will be kicked out in the condensate separator.

why such design? is the "purpose" of this oil vent tube - a necessary to keep the cylinders lubricated and to keep the cross tubing lubricated?

kinda like 2 stroking (oil vent tube injections oil vapor into cylinder) plus 4 stroking (oil bath on the crank) at the same time.

sorry for the dumb questions. just trying to make head and tails of how it works.

 

[rcontrera]

This compressor is splash lubricated. That means that the stuff under the pistons gets coated with oil every time the splash piston dunks into the sump. In your MaxAir case, it is a Coltri machine so the 4th stage is located under the sump level.

However, no oil splashes up to the cylinders to lubricate the pistons. This is where the oil that is sucked into the first stage comes in. It coats the wall of the cylinder and actually lubricates the rings. Then it is shoved on down stream to the next cylinder to lubricate there and so on. The tubing between the cylinders doesn't need lubricating but it gets it anyway.

I think that you will find that even on compressors with pressurized oil systems, many will still vent the sump to the first stage suction.