4. Operation_________ (Ref. Fig. 003)
A. APU Drain System On the ground, cold drains (oil + fuel) are collected in the drain tank. In flight (APU in operation or not) above 200kts forward air speed, sufficiently low pressure is generated at the drain mast to permit discharging of the drain tank contents via the suction line. Hot and/or pressurized waste fuel is drained directly overboard. Rain and cleaning fluids are collected separately and also drained directly overboard.
B. APU Compartment Drainage Rain or cleaning agents may reach the compartment via its ventilation louver. Oil and fuel may reach the compartment only in case of system leaks (fuel supply, hydraulic actuation or lubrication) or oil spillage during APU servicing. If rain, cleaning fluids or fuel of sufficient quantity enter or leak within the compartment at any location, they flow to the lowest point and from there through the drain mast overboard. Only insignificant quantities of these fluids will remain in the compartment along the drainage path.
POWER PLANT DRAIN SYSTEM - DESCRIPTION AND OPERATION
____________________________________________________
1.
General
_______ A drain system is incorporated to collect fluids that are lost from the various APU components and to drain the exhaust system of any unwanted fluids such as rain water and cleaning fluids. For safety and operational reasons, all these fluids are collected and drained overboard via the APU compartment drain mast. The APU compartment is designed to permit all excess fluids to gather at the lowest point from where they are discharged overboard via the drain mast. All components of the drain system are fireproof.
2.
Component Location
__________________
(Ref. Fig. 001)
-------------------------------------------------------------------------------FIN | FUNCTIONAL DESIGNATION | PANEL|ZONE|ACCESS | ATA | | | | DOOR | REF. -------------------------------------------------------------------------------DRAIN LINES 316 316AR 49-17-41
3. System Description
__________________ (Ref. Fig. 001, 002, 003) Drain lines are connected to the fuel/oil pump drain, IGV actuator seal drain and the surge control valve. These go to a collector line that runs along the underside of the APU and then to the drain tank. The drain tank is installed on the access door 316AR. The drain line from the tank runs along the access door to the drain mast. At 200 kts air speed the air flow causes a suction at the exit from the drain mast. This air flow across the drain mast causes a suction in the drain line. The suction produced is enough to remove the contents of the drain tank. A vent line between the drain mast and the drain tank ventilates the drain tank and lines. Exhaust muffler drain, turbine plenum drain and the load compressor cavity drain are are drained directly overboard through the mast.
All drains are collected at the 3 ports of the APU drain bracket. This
bracket establishes the interface with the A/C APU drain system:
-
the FWD port collects the water and cleaning agents;
-
the MID port collects the hot and/or pressurized fuel;
-
the AFT port collects the cold fuel. The fluids discarded through the APU drain mast do not have a dangerous effect on the APU or any other components. The gearbox is vented to the APU exhaust through a vent line. All the parts used in the drainage system are fireproof.
R EFF : 001-049, 101-105, 107-107, 151-199, 49-17-00Page 1 201-210, Config-2 Aug 01/05
CES
Drain System - Component Location
Figure 001
CES
APU Drain System Figure 002
R EFF : 001-049, 101-105, 107-107, 151-199, 201-210, Page 349-17-00Config-2 Aug 01/05
CES
Drain System - Schematic
Figure 003
CES
A. APU Drain System All components of the APU drain system are installed on the R/H compartment access door 316AR. Metallic bellows form the interface with the APU drain bracket. When the access door is opened, the system separates at this interface. The drain mast, attached to the door, is positioned far enough behind the APU air intake to prevent the intake ingesting the drained fluids.
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Drains from the forward and center APU drain ports are led directly overboard via separate drain lines to the drain mast.
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Drains from the aft APU drain port are lead to a drain tank. From there a drain and a vent line lead to the drain mast.
4. Operation
_________
A. APU Drain System On the ground, cold drains (oil + fuel) are collected in the drain tank. In flight (APU in operation or not) above 200kts forward air speed, sufficiently low pressure is generated at the drain mast to permit discharging of the drain tank contents through the suction line. Hot and/or pressurized waste fuel is drained directly overboard. Rain and cleaning fluids are collected separately and also drained directly overboard.
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