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MAINTENANCE MANUAL
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LEFT FORWARD MAINBOOST PUMP
APU FUELCHECK VALVE
DC FUEL PUMP
AND PRESSURE
SWITCH
APU FUELSHUTOFF VALVE
APU FUEL PUMP
SHUTOFF PRESSURE
SWITCH
APU FUEL LINEAND SHROUD APU
FORWARDAPU FLAMEAFT APUARRESTOR FLAME ARRESTOR,APU SUMP DRAINVALVE, ANDDRAIN MAST
APU Fuel Feed SystemFigure 1
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MAINTENANCE MANUAL
SEE A
PRESSURE SW PORT
CHECK VALVE DISCHARGE VALVE
VANE PUMP
(DRY)
ELECTRICAL CONNECTOR "O" RING INLET PORT PLUNGER VALVE
A
1 2 M
3
DC FUEL PUMP
DC Fuel Pump
Figure 2
OUTLET PORT CHECK VALVE
FUEL INLET
HOUSING (INSIDE TANK) (WET)
REAR SPAR
EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. ú
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MAINTENANCE MANUAL
(2)
Function
(a)
The pump and drive motor draw fuel through the inlet port. The fuel circulates through the pump and drive motor and exits at the outlet port. The plunger valve controls the inlet port. Mounting the pump and drive motor on the housing opens the plunger valve. Detaching the pump and drive motor from the housing closes the plunger valve to allow removing the pump and drive motor without defueling.
(b)
The outlet port check valve prevents back flow of fuel from the fuel tank into the pump and drive motor. Operating the pump and drive motor generates internal pressure, forcing the check valve open. The open check valve allows fuel delivery to the APU or main boost pumps.
(c)
The discharge valve acts as a relief valve, controlling the pump output pressure. The fuel inlet receives bypassed fuel, from the outlet port, through the open discharge valve if outlet port pressure requires relief.
(d)
Fuel enters the drive motor, to provide cooling and lubrication, through the check valve in the drive motor. The thermal fuse provides additional drive motor overheat protection. The fuse trips at 350°F |14°F (177°C |8°C).
B.
APU Shutoff Valve (Fig. 3)
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本文链接地址：757 AMM 飞机维护手册 燃油 CHAPTER 28 - FUEL 4(7)
