Bearing Drain Passage Sizing

[oneb91]

I'm responsible for designing piping supplying and returning lubricant to bearings enclosed in a turbine casing. The sump pressure is a few inches of water vacuum. Oil supply is pressurized at ~25 psig. On one bearing we supply air to the bearing to seal it from outside hot air.

Compared to our past work, I think the housing drain passage and the pipe connection I was given are too small.

If the bearing drain passage is too small, what is the risk? Do we blow oil mist out of the bearing, lose the capillary action of the oil flow, ???

 

[diamondjim]

You are the man! Increase the
sizes if you have the room.
Err on the safe side.

 

[plasgears]

Consider that most vent returns are several times the diameter of supply pipes. The return is handling both oil and seal pressurization air.