DOC AIRBUS | AMM A320FOIL DISTRIBUTION COMPONENTS - DESCRIPTION AND OPERATION
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
1. General
The oil components contains:
** ON A/C NOT FOR ALL The oil components contains:
Oil Distribution- Oil Lubrication Unit
- Main Heat Exchanger (MHX)
- Engine Surface Air Cooling Oil Cooler (SACOC)
- Eductor Valve
- Non Return Valve
2. Component Description
A. Oil Lubrication Unit
(1) The lubrication unit is installed on the Accessory Gearbox (AGB) rear face at 7 O'clock aft looking forward. The unit is driven by a shaft with splines engaged into the AGB and is fixed on the AGB pad by seven screws. A rotational seal is installed on the AGB to prevent oil leakage between AGB and lubrication unit (Ref. AMM D/O 72-60-00-00).
(2) The lubrication unit has a single aluminum cast housing that contains the items that follow:
- Six gerotor pumps (one double supply pump and five scavenge pumps)
- One filter cartridge after the supply pumps
- Two scavenge screen plugs for scavenge pumps (one double stage strainer and one triple stage strainer)
- One anti-leak valve to prevent oil tank drainage and siphoning when engine is shutdown.
- One pressure relief valve to limit the internal pressure of the lubrication unit
- One bypass valve to bypass the filter to allow oil supply when the filter is clogged
- A driven gear and a shaft pinion to transmit torque from AGB.
B. Main Heat Exchanger
(1) The Main Heat Exchanger (MHX) cools the oil by using fuel as a cooling medium. The MHX is installed on the fan frame at 10 o'clock.
(2) The MHX is an aluminum shell and tube fuel/oil heat exchanger.
(a) The primary components of the MHX are:
- Tubular U tube heat exchanger matrix
- Cast aluminum case and end cover
- Oil Pressurize Valve
- Oil bypass valve
- Fuel bypass valve
- Oil and fuel ports
- Mounting feet.
C. Engine-Surface Air-Cooling Oil-Cooler
(1) The engine Surface Air-Cooling Oil-Cooler (SACOC), cools the oil by using air as a cooling medium. It is composed of 2 segments symmetrically installed on the inner surface of the fan frame. The cooler is configured as 2 flow paths. Each sub-assembly is designed to operate in parallel to provide the cooling required. Each sub-assembly is designed to provide cooling for half of the oil flow. The flow will be balanced between panels by pressure drop, the panels are in parallel.
(2) Each SACOC is composed of:
- An oil inlet/outlet manifold
- A shroud assy
- Mounting features (one hard mount block and six sliding mount assy)
- A plain fin core (matrix)
- A inlet passage and a bypass passage
- A thermal/pressure relief valve
D. Eductor Valve
(1) The function of the eductor valve is to control engine forward sump pressurization by providing primary air to an eductor tube in the center vent in order to increase delta pressure across engine forward A-sump seals at low engine speed. It is mounted at 8 O'clock aft looking forward, on a bracket fixed to the combustion case and the High Pressure Turbine (HPT) case.
(2) The eductor valve is an inlet pressure controlled, altitude compensated poppet style shutoff valve.
(3) The eductor is composed of:
- A housing with 3 mounting lugs and inlet and outlet fittings
- A piston with a poppet
- A pilot servo
- An evacuated bellow
- A visual position indication.
E. Non Return Valve
(1) The non-return valve function is to prevent the engine oil drainage and siphoning in the AGB when engine is shutdown. It is installed in the oil supply line downstream the Lube Unit, at 9 O'clock aft looking forward. The non return valve is composed of a housing, a valve and a spring. When oil pressure applies, the valve opens to allow oil flow. When no pressure applies, the valve closes, preventing oil from being siphoned in the AGB at engine shutdown.
3. Operation/Control and Indicating
A. Oil Lubrication Unit
(1) The lubrication unit is supplied with oil from oil tank. It pressurizes (supply pump), filters (oil supply filter) and delivers oil to the engine sumps/AGB/Transfer Gear Box (TGB) for lubrication and cooling of the gears and bearings. It recovers oil through the five scavenge pumps to return it to the oil tank.
Due to an air/oil ratio important for the B and C sump scavenge pumps, these pumps must have constantly a sufficient quantity of oil in inlet to have an optimum function. The pumps receive this additional oil from the filter outlet through the internal lubrication system
Due to an air/oil ratio important for the B and C sump scavenge pumps, these pumps must have constantly a sufficient quantity of oil in inlet to have an optimum function. The pumps receive this additional oil from the filter outlet through the internal lubrication system
B. Main Heat Exchanger
(1) Fuel from the boost pump stage of the fuel pump and from Fuel Metering Unit (FMU) enters the end cover inlet (Ref. AMM D/O 73-10-00-00). It flows through the tubes of the matrix and exits at the end cover outlet to feed the main pump stage of the fuel pump. The fuel portion of the exchanger is equipped with a pressure relief valve which bypasses fuel around the exchanger in case of clogging.
Oil from the lubrication unit, through the Servo Fuel Heater (SFH) and the SACOC, enters the case oil inlet. The oil flows around the fuel tubes of the matrix, routed by interior baffles, and exits at the case oil outlet to feed sumps and AGB/TGB. The oil portion of the exchanger is equipped with a pressure relief valve which bypasses oil through the exchanger in case of clogging.
Oil from the lubrication unit, through the Servo Fuel Heater (SFH) and the SACOC, enters the case oil inlet. The oil flows around the fuel tubes of the matrix, routed by interior baffles, and exits at the case oil outlet to feed sumps and AGB/TGB. The oil portion of the exchanger is equipped with a pressure relief valve which bypasses oil through the exchanger in case of clogging.
(2) The oil pressurizing valve at the oil outlet of the MHX, pressurized oil to feed the engine oil dampers. The oil to fuel heat transfer is achieved through conduction and convection within the exchanger where both fluids are circulated.
C. Eductor Valve
(1) The eductor valve controls the Delta Pressure (DP = P outside A-sump - P inside A-sump) of A-sumps seals (#1 and #3 bearing carbon seals) to avoid oil leakage of the A-sump.
When DP is too low, the carbon seals do not function properly and they may leak. In this condition, the eductor valve opens, forcing the ventilation of the A-sump, decreasing the pressure inside the sump. The DP comes back to a value allowing the good functioning of the carbon seals.
When DP is too low, the carbon seals do not function properly and they may leak. In this condition, the eductor valve opens, forcing the ventilation of the A-sump, decreasing the pressure inside the sump. The DP comes back to a value allowing the good functioning of the carbon seals.