DOC AIRBUS | AMM A320FDISTRIBUTION - DESCRIPTION AND OPERATION
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
1. General
The lubrication functions are provided by the lubrication unit.
The lubrication unit provides oil under the required pressure for lubrication of the 4 engine sumps, for scavenge of the oil after lubrication and circulation to the oil/fuel heat exchanger and oil tank. The lubrication unit its mounted on the AGB front face.
** ON A/C NOT FOR ALL The lubrication functions are provided by the lubrication unit.
Lubrication UnitThe lubrication unit provides oil under the required pressure for lubrication of the 4 engine sumps, for scavenge of the oil after lubrication and circulation to the oil/fuel heat exchanger and oil tank. The lubrication unit its mounted on the AGB front face.
2. Description
The lubrication unit has a single housing containing the following items:
** ON A/C NOT FOR ALL The lubrication unit has a single housing containing the following items:
- Five positive displacement pumps (one oil supply and 4 scavenge pumps).
- Six filters (one oil supply filter, 4 chip detectors and scavenge pumps filters).
- One relief valve (on oil supply pump discharge side).
- Two clogging indicators (one for the oil supply filter and one for the main scavenge filter).
- Two bypass valves (one for the oil supply filter and one for the main scavenge filter).
3. Supply
A. General
Oil from the oil tank is routed to the lube pump which is protected upstream by a strainer and magnetic plug located at the bottom of the tank and downstream by a supply filter. The oil pressure is between 2.50 bars and 2.70 bars (36 PSID - 39 PSID).
The oil then is routed through a line.
Tappings are provided on this line to distribute the oil to the various items to be lubricated (forward sump (bearings 1, 2, 3), aft sump (bearings 4, 5), TGB, AGB).
Oil from the oil tank is routed to the lube pump which is protected upstream by a strainer and magnetic plug located at the bottom of the tank and downstream by a supply filter. The oil pressure is between 2.50 bars and 2.70 bars (36 PSID - 39 PSID).
The oil then is routed through a line.
Tappings are provided on this line to distribute the oil to the various items to be lubricated (forward sump (bearings 1, 2, 3), aft sump (bearings 4, 5), TGB, AGB).
B. Description
(1) Protection upstream supply pump
The lube supply element of the pump is protected by a strainer and a magnetic plug located at the bottom of the oil tank.
The lube supply element of the pump is protected by a strainer and a magnetic plug located at the bottom of the oil tank.
(2) Supply pump
(a) The supply element of the 5 gerator type positive displacement pump is powered by a single drive shaft driven by the accessory gearbox (AGB).
(N = TBD percent N2)
(N = TBD percent N2)
(b) The external tooth gear has one lobe more than internal tooth gear it meshes with. The gears rotate in the same direction but with different angular speeds. The volume corresponding to the missing tooth is therefore displaced from the inlet to the outlet.
(c) Since the 2 gear rotational axes are mutually offset, the space between the two tooth profiles progressively increases until maximum volume is reached-i.e. when rotated by approximately 180 degrees.
During the initial half-cycle, the volume increases and moves past the suction inlet creating a partial vacuum which sucks in the oil.
During the next half-cycle, the volume progressively decreases, discharging the oil through the outlet.
During the initial half-cycle, the volume increases and moves past the suction inlet creating a partial vacuum which sucks in the oil.
During the next half-cycle, the volume progressively decreases, discharging the oil through the outlet.
(d) The supply element provides a flow rate of 2495 l/h (2627 Qts/h) at take off and a normal pressure of 60 PSID.
(3) Supply circuit
The supply circuit main components are the supply pump and the supply filter. At engine start-up the supply pump draws oil from the tank and pressurizes it. The pressure relief valve bypasses any excess flow to the suction side of one of the scavenge pumps.
The supply circuit main components are the supply pump and the supply filter. At engine start-up the supply pump draws oil from the tank and pressurizes it. The pressure relief valve bypasses any excess flow to the suction side of one of the scavenge pumps.
(4) Lube pump supply filter
Oil under pressure from the supply pump is filtered through a 15 micron filter element which protects the lube supply nozzle from contamination.
The inlet filtered oil is thus supplied to critical components.
Downstream of the supply pump, the oil flows through the supply filter assembly. The filter has the following components.
Oil under pressure from the supply pump is filtered through a 15 micron filter element which protects the lube supply nozzle from contamination.
The inlet filtered oil is thus supplied to critical components.
Downstream of the supply pump, the oil flows through the supply filter assembly. The filter has the following components.
(a) One filter (15 microns)
(b) One clogging indicator subjected to the upstream and downstream pressures of the supply filter.
The indicator has a red warning indicator and is rearmed manually (2 bars to 2.3 bars) (29 PSID to 33 PSID).
The indicator has a red warning indicator and is rearmed manually (2 bars to 2.3 bars) (29 PSID to 33 PSID).
(c) One bypass valve which opens if the supply filter clogs (2.50 bars to 2.70 bars) (36 PSID to 39 PSID).
(d) Two capped provisions for a pressure gage upstream of the filter, and a temperature sensor.
(5) Engine lubrication
Downstream of supply filter, the oil flows through the three lubrication unit outlets to the forward sump, aft sump and the AGB where it is bypassed externally to the transfer gearbox (TGB).
The following oil quantities flow at take off:
Downstream of supply filter, the oil flows through the three lubrication unit outlets to the forward sump, aft sump and the AGB where it is bypassed externally to the transfer gearbox (TGB).
The following oil quantities flow at take off:
- Total = 2495 l/h (2637 Qts/h),
- Forward engine sump = 1195 l/h (1263 Qts/h),
- Aft engine sump = 475 l/h (502 Qts/h),
- AGB = 535 l/h (565 Qts/h),
- TGB = 260 l/h (275 Qts/h),
- Anti siphon = 30 l/h (31.7 Qts/h).
(6) Anti siphon System
The supply line from the oil tank to the pump supply has an antisiphon device to prevent the drainage of the tank into the gearboxes and sumps when the engine is shut down for extended periods.
The supply line from the oil tank to the pump supply has an antisiphon device to prevent the drainage of the tank into the gearboxes and sumps when the engine is shut down for extended periods.
(7) Oil supply circuit indication
(a) Oil pressure
The oil pressure transmitter enables the oil pressure within the system to be monitored. This pressure is indicated by the ECAM system.
The oil pressure transmitter enables the oil pressure within the system to be monitored. This pressure is indicated by the ECAM system.
(b) Oil temperature
The oil temperature is related to engine speed, fuel temperature and oil flow rate.
Max oil supply temperature:
The oil temperature is related to engine speed, fuel temperature and oil flow rate.
Max oil supply temperature:
- steady state 140 deg.C (284 deg.F),
- Transient 155 deg.C (311 deg.F)(20 mn period).
(c) A low pressure switch is installed in order to warn the crew, when the decreasing pressure reaches 13 PSID.
C. Internal Lubrication of Lubrication Unit
The internal lubrication of the lubrication unit is provided by oil bled from the supply pump discharge circuit via a passage machined in the housing. This oil enters the central conduit of the drive shaft. From there, it flows radially through holes in the shaft to lubricate the split bushing and then flows on toward the other end of shaft to lubricate the shaft external splines via 2 calibrated orifices.
The internal lubrication of the lubrication unit is provided by oil bled from the supply pump discharge circuit via a passage machined in the housing. This oil enters the central conduit of the drive shaft. From there, it flows radially through holes in the shaft to lubricate the split bushing and then flows on toward the other end of shaft to lubricate the shaft external splines via 2 calibrated orifices.
4. Scavenge
A. General
The oil which has lubricated the engine bearings, accessory gearbox and TGB is scavenged by 4 pumps protected by a strainer equipped with a magnetic chip detector.
This oil is then collected in a single line comprising:
The oil which has lubricated the engine bearings, accessory gearbox and TGB is scavenged by 4 pumps protected by a strainer equipped with a magnetic chip detector.
This oil is then collected in a single line comprising:
- a scavenge filter,
- an oil/fuel heat exchanger.
B. Description
The scavenge circuit main components are a follows:
The scavenge circuit main components are a follows:
- Four scavenge filter with chip detectors,
- Four scavenge pumps,
- one common scavenge filter,
- oil/fuel heat exchanger.
(1) Protective upstream scavenge pumps
The air/oil mixtures are passed through the chip detectors and the scavenge filters, and then to the specific scavenge pump. The AGB scavenge pump also receives the flow internally bypassed from the supply pump through the relief valve.
The air/oil mixtures are passed through the chip detectors and the scavenge filters, and then to the specific scavenge pump. The AGB scavenge pump also receives the flow internally bypassed from the supply pump through the relief valve.
(2) Scavenge pump
After lubrication, the 4 scavenge pumps scavenge the air/oil mixture from the 2 engine sumps and gearboxes through 4 tubes external to the lubrication unit.
The 4 scavenge elements of the 5-gerotor-type-positive displacement pumps are powered by the same AGB-driven single drive shaft as the supply element (pump).
They have the same technology and principle of operation as those described for the supply pump.
Flow rate of the scavenge system at take off:
After lubrication, the 4 scavenge pumps scavenge the air/oil mixture from the 2 engine sumps and gearboxes through 4 tubes external to the lubrication unit.
The 4 scavenge elements of the 5-gerotor-type-positive displacement pumps are powered by the same AGB-driven single drive shaft as the supply element (pump).
They have the same technology and principle of operation as those described for the supply pump.
Flow rate of the scavenge system at take off:
- Forward sump scavenge: 2800 l/h (2957 Qts/h),
- Aft sump scavenge: 1750 l/h (1850 Qts/h),
- AGB : 2495 l/h (2637 Qts/h),
- TGB : 2495 l/h (2637 Qts/h).
(3) Scavenge filter
The flows from the 4 scavenge pumps are mixed together at the scavenge common filter inlet. This filter assembly consists of the following:
The flows from the 4 scavenge pumps are mixed together at the scavenge common filter inlet. This filter assembly consists of the following:
(a) One 25 micron filter.
(b) One clogging indicator, similar to the one on the supply filter (2 bars to 2.3 bars) (29 PSID to 33 PSID).
(c) An upstream and a downstream provision for measurement of filter pressure loss as a function of clogging.
(d) One bypass valve which opens if the filter clogs.
(2.5 bars to 2.7 bars) (36 PSID to 39 PSID)
(2.5 bars to 2.7 bars) (36 PSID to 39 PSID)
(e) One provision for a temperature sensor downstream of the filter.
(4) Oil/fuel heat exchanger
The scavenged oil flows the lubrication unit through a pipe outside the unit to the servo fuel heater and the main oil/fuel heat exchanger, and then back to the oil tank.
The scavenged oil flows the lubrication unit through a pipe outside the unit to the servo fuel heater and the main oil/fuel heat exchanger, and then back to the oil tank.
(a) General
The oil/fuel heat exchanger cools the oil by using fuel as a cooling medium.
The oil/fuel heat exchanger is installed on the fuel pump, between the AGB aft face and the servo fuel heater at the 9 o'clock position, aft looking forward.
The oil/fuel heat exchanger cools the oil by using fuel as a cooling medium.
The oil/fuel heat exchanger is installed on the fuel pump, between the AGB aft face and the servo fuel heater at the 9 o'clock position, aft looking forward.
(b) Description
The oil/fuel heat exchanger is of tubular type. It consists of a removable core, housing and cover.
The oil/fuel heat exchanger is of tubular type. It consists of a removable core, housing and cover.
1 The core consists of a cylinder, end plates, and fuel tubes.
The fuel tubes are attached to the end plates. Two inner baffles lengthen the oil circulation path around the fuel inlet tubes.
The fuel tubes are attached to the end plates. Two inner baffles lengthen the oil circulation path around the fuel inlet tubes.
2 The housing contains the core of the oil/fuel heat exchanger. The following items are located on the outside of the oil/fuel heat exchanger housing:
- One oil pressure relief valve and one fuel pressure relief valve,
- One drain port which collects possible fuel leaks from core and inter seal cavities and prevents fuel from leaking into the oil cavity and contaminating the oil system,
- One port for a fuel-out temperature probe (optional),
- One attaching flange for the servo fuel heater,
- One flange for attachment to the fuel pump,
- One port on fuel-in for fuel returned from Hydromechanical Unit (HMU) after circulating through the Integrated Drive Generator (IDG) oil cooler.
3 The cover provides access to the oil/fuel heat exchanger for core installation.
(c) Operation
The oil to fuel heat transfer is achieved through conduction and convection within the exchanger where both fluids are circulated.
Fuel from the fuel pump and from HMU enters the inlet. It flows in one direction through one half of the core tubes to the end cover. At the end cover, the fuel flows around the baffle and back through the other half of the core tubes to the fuel outlet. The fuel portion of the exchanger is equipped with a pressure relief valve which bypasses fuel around the exchanger if core clogging impedes fuel flow.
Oil from the scavenge system enters the oil inlet. The oil flows around the fuel tubes, as routed by interior baffles, and exits at the oil outlet. The oil portion of the exchanger is equipped with a pressure relief valve which bypasses oil through the exchanger if core clogging impedes oil flow.
The oil to fuel heat transfer is achieved through conduction and convection within the exchanger where both fluids are circulated.
Fuel from the fuel pump and from HMU enters the inlet. It flows in one direction through one half of the core tubes to the end cover. At the end cover, the fuel flows around the baffle and back through the other half of the core tubes to the fuel outlet. The fuel portion of the exchanger is equipped with a pressure relief valve which bypasses fuel around the exchanger if core clogging impedes fuel flow.
Oil from the scavenge system enters the oil inlet. The oil flows around the fuel tubes, as routed by interior baffles, and exits at the oil outlet. The oil portion of the exchanger is equipped with a pressure relief valve which bypasses oil through the exchanger if core clogging impedes oil flow.
C. Indicating
The filter clogging system indicates that the filter is clogged, when the scavenge filter pressure differential reaches 25.5 PSID.
The filter clogging system indicates that the filter is clogged, when the scavenge filter pressure differential reaches 25.5 PSID.
5. Breather/Vent System
A. General
To ensure satisfactory lubrication throughout the flight envelope, the oil pressure is maintained within the engine oil supply system.
This results in:
To ensure satisfactory lubrication throughout the flight envelope, the oil pressure is maintained within the engine oil supply system.
This results in:
- Some air being entrapped in the main oil flow (scavenge subsystem),
- Some oil droplets escaping with the air of the pressurization sub system. For safety and oil consumption reasons, the entrained air in the scavenged oil is separated by the tank deaerator and is then directed to the venting subsystem through the TGB. The oil contained in the pressurized air is collected by a deaerator incorporated in the low pressure turbine shaft and is returned to the engine oil system.
B. Oil Seal Pressurization Subsystem
The oil seal pressurization subsystem consists of the following:
Labyrinth seals, composed of a stationary member (rub strip) and a rotating member (multi-toothed), provide a positive, dependable, long life system. Pressurization air is extracted from the fan booster discharge.
This air is distributed internally through the engine to each sump pressurization cavity and oil seal. The passage between the core rotor air duct and the low pressure shaft is utilized to conduct pressurization air to the aft sump, therefore no external piping is needed for the sump pressurization air. The pressurization air completely surrounds the sumps for improved wall cooling and sealing.
The oil seal pressurization subsystem consists of the following:
- Pressurizing air from the fan booster discharge,
- Pressurizing air distribution passages,
- Sump cavity seals,
- Sump pressure cavity and piping.
Labyrinth seals, composed of a stationary member (rub strip) and a rotating member (multi-toothed), provide a positive, dependable, long life system. Pressurization air is extracted from the fan booster discharge.
This air is distributed internally through the engine to each sump pressurization cavity and oil seal. The passage between the core rotor air duct and the low pressure shaft is utilized to conduct pressurization air to the aft sump, therefore no external piping is needed for the sump pressurization air. The pressurization air completely surrounds the sumps for improved wall cooling and sealing.
C. Sump Vent Subsystem
The sump vent subsystem consists of the following components :
External engine piping is minimized by venting the sumps through the exhaust nozzle.
The tank is vented to the forward sump through the transfer gearbox and radial drive shaft housing. Thus, oil tank pressure is adequate to provide pressurization of the supply pump inlet.
The sump vent subsystem consists of the following components :
- Air/oil separators incorporated in the low pressure shaft,
- Center vent piping.
External engine piping is minimized by venting the sumps through the exhaust nozzle.
The tank is vented to the forward sump through the transfer gearbox and radial drive shaft housing. Thus, oil tank pressure is adequate to provide pressurization of the supply pump inlet.