LUBRICATION SYSTEMS Flashcards
What type of lubrication System do most gas turbine engines use?
Self contained Dry slump lubrication
What sub-systems does the basic lubrication system consist of?
- oil reservoir and supply system
- scavenge System
- vent system
- monitoring system
What is the oil reservoir system also know as?
Pressure oil system
What components are contained within the pressure oil system?
- oil tank
- supply lines
- supply pump
- supply filter
Where is the supply filter located and what is its purpose?
Downstream of supply pump.
- removes foreign particles from oil before it reaches oil nozzles.
What is a scavenge System for?
Returning oil from bearing and gearbox components to the oil tank, to prevent accumulation of lubrication.
Why is a vent system used?
Releases air from system into the atmosphere.
- air pumped into the forward bearing and gearbox to replace air pumped out by the scavenge System.
Why would bearing compartments have a vent system?
Release sealing air and maintain airflow across the seals.
What is required when air is pumped into the oil tank by the scavenge System?
Removal of the air.
What is the oil monitoring system?
Measures oil quantity, oil pressure and oil temp.
Sends signals to cockpit if pressure low or scavenge filter is blocked
What sensors does a oil monitoring system require?
- quantity
- pressure
- temp
- low pressure switch
- clog switch
How can contamination in the oil be inspected?
Magnetic chip detectors, inspecting filters
Where are magnetic chip detectors located?
Usually on individual scavenge lines to make the source of contamination finding easy.
What are the types of quality transmitters and where are they usually located?
- capacitance
- reed
(On top of oil tank so it can be changed without draining the tank)
What is the low oil pressure switch warning accompanied with in the cockpit?
An acoustic warning
What are the two main types of temperature sensor?
- thermistor
- thermocouple
What is Spectrometric Oil Analysis Programme (SOAP) for?
Find about internal wear of lubricated engine components.
Particles between 0.001mm - 0.02mm
What size particles does the scavenge oil filter collect?
Larger particles (more than 0.015mm)
Problem with this is that filter does not get changed very often and each inspection takes time.
What is an easier and less time consuming method of gaining information about the condition of oil?
Magnetic chip detectors.
When does the resistance of the magnetic chop detector decrease?
When particles connect with the magnets.
Electronic control unit sends maintenance message when resistance is too low.
Why is there a slow flow of oil from the tank to the gearbox?
Siphon effect (anti-siphon device installed)
Important to check oil quantity between 5-20 mins after engine shutdown.
Why is an oil overflow dangerous?
Oil can be pumped into forward bearing compartment of de-oiler.
What must always be replaced when removing magnetic chip detectors?
O rings
Or use the reusable seal
