Purge mist high pressure causes oiler cup to deplete

[Wkcoo]

Could slightly higher purge mist pressure cause bearing housing sump oil to flow out of laby seal, and thus depleting the oiler cup level of idle pumps? has anyone encountered such situation before?

Design mist manifold pressure: 0.6psig
Current pressure: 0.9psig
Hi alarm: 1.0 psig

I face this situation where around 5-6 pumps oiler cup are empty, and I suspect the pressure caused it. But it doesn't pass my own funny look test because 0.3psi increase probably won't caused such leak.

 

[JJPellin]

What type of oiler are you using? Are your oilers pressure equallized? Do your bearing housings have cooling fans. Oil mist pressure should not be a cause of the oil leak.

Johnny Pellin

 

[Wkcoo]

Hi Pellin, it's constant level oiler cup. The pressure is equalized by the bearing housing breathing vent (gooseneck). No cooling fans.

To me, that 0.3 pound increase shouldn't be the issue but this is what reported by the Operation team.

 

[TugboatEng]

Where did the oil go?

 

[JJPellin]

So, it is not pressure equalized. A goose neck vent is not pressure equalization. It is probably a simple Trico oil bulb oiler or something like that. It probably has simple laby seals rather than bearing isolators. I have to keep guessing since you are not providing enough details. The oil level may be too high. The oiler may have failed. You may have excessively large reclassifiers on the oil mist. You should have an overflow on the oiler so that the mist does not cause the oil level to go too high. How is that overflow piped?

Turn the oil mist pressure down and see if that helps. Stop filling the bulb. Let it sit empty and see if the oil level stabilizes. Once a leak like this starts, it can continue to wick oil out until you force it to stop.

Johnny Pellin

 

[Wkcoo]

Hi all, an update of the issue:

After reducing the misf manifold pressure from 0.9 to around 0.5 psig, apparently the issue stopped.

The exact mechanism of oil loss is still unknown, and as Pellin mention there can be multiple reasons apart from the oil mist.