Turbine engine lubrication systems have three sub-systems: the pressure system supplies clean oil at the proper pressure and temperature to bearings and gears. The scavenge system picks up used oil and returns it to the tank to be recirculated. The breather/vent system removes contaminated air from bearing housings through a de-oiler before blowing it overboard.

1. Jet Propulsion
Oil

2. Turbine engine lubrication systems are logically
divided into three basic sub-systems. These
are:
• Pressure system
• Scavenge system
• Breather/Vent system

3. Pressure System
• The pressure subsystem supplies the correct
amount of clean lubricating oil at the proper
pressure and temperature to all of the
bearings and gears.
• It consists of the oil tank, the pressure pump,
the pressure relief valve, the main oil filter, the
oil cooler (hot-tank systems), the bearing
filters, and the oil jets.

4. Scavenge System
• The scavenge subsystem picks up the oil after it has
performed its lubrication and cooling functions and returns
it to the oil tank where it can be re circulated through the
system.
• Air drawn in with the scavenge oil is separated in the tank
by a de-aerator and is vented to a de-oiler.
• The de-oiler separates the air still in the oil and discharges
it overboard.
• The scavenge subsystem consists of the sumps, in which oil
from the bearings and gears collects, the various scavenger
pumps.
• The oil cooler with its bypass valve and temperature bypass
valve are in the scavenge subsystem of cold-tank systems.

5. Breather/Vent system
• There is a steady air-stream coming from the bearing
housings. This air-stream, called breather air, becomes
contaminated with lubrication oil during operation
and must be de-oiled with a component called de-oiler.
• De-oilers are often attached to or inside the accessory
gear box, or are part of the turbine/compressor
shaft .
• After the de-oiling process, the air is blown overboard
to the atmosphere.