Bleed and Surge Air - Component Location Figure 001 (SHEET 1)
R EFF : 106-106, 108-149, 211-299, 301-399, 49-51-00Page 2 Config-3 Aug 01/05
CES
Bleed and Surge Air - Component Location Figure 001 (SHEET 2)
R EFF : 106-106, 108-149, 211-299, 301-399, 49-51-00Page 3 Config-3 Aug 01/05
CES During the APU start sequence or the APU BLEED pushbutton switch is ON but no demand signal is available, the bleed control valve is in the discharge position. When the APU BLEED pushbutton switch is in the ON position and a demand signal from the aircraft system is available, the ECB commands the bleed control valve in the delivery position.
4. Interface
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The bleed and surge air system has an interface with:
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the APU Bleed Air Supply and Crossbleed System (Ref. 36-12-00),
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the APU Load Compressor (Ref. 49-23-00),
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the APU Fuel Control (Ref. 49-32-00),
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the Control and Monitoring System (Ref. 49-61-00).
5. Component Description
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(Ref. Fig. 002)
A. Bleed Control Valve (BCV) The BCV consists of a spherical body with three flanged connections. It has a valve section with a butterfly flap, an actuator and a servo valve. The butterfly flap is driven by the fixed-link linear rotary-actuator. The actuator is controlled by the servo valve which is operated by fuel pressure from the FCU. The ECB sends control current signals to the two solenoids of the servo valve. This allows the fuel pressure to move the actuator and position the butterfly flap in the demanded position. A Linear Voltage Differential Transducer (LVDT) transmits position signals to the ECB. The LVDT is located inside the piston of the actuator.
B. Compressor Discharge Pressure-Sensors The two compressor discharge pressure-sensors (delta P and P) are contained in one unit. The sensors measure the load compressor discharge air pressure.
C. Compressor Discharge Pressure Sensor The compressor discharge pressure sensor is a unit which contains a static pressure and a differential pressure sensor. It is located at the APU air intake plenum. The pressure sensors are varable resistor devices. The ECB uses the sensor output voltage for the calculation of the the air flow and to give the APU BLEED pressure indication for the APU page on the lower ECAM display unit.
APU Bleed Control Valve - Operation
Figure 002
CES 6. Operation/Control and Indication
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(Ref. Fig. 003, 004)
A. Start Procedure of APU Bleed-Air Supply The start sequence of the APU is complete when the APU acquires 95% speed (Ref. AMM 49-42-00). During the start sequence the bleed control valve is in the discharge position. Above the acquired 95% speed the APU is obtainable for the supply of bleed-air and electrical power. Information on the ECAM and the overhead panel shows that the APU is available: - on the APU page of the lower ECAM display unit, the green AVAIL
indication comes on, - on the APU overhead panel 25VU, (the green AVAIL legend on the APU
START pushbutton switch comes on, When the APU is available you can push the APU BLEED pushbutton switch to start the APU bleed-air supply. When you push the APU BLEED pushbutton switch and there is a demand signal available:
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the blue ON legend in the APU BLEED pushbutton switch comes on,
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the BMC starts a test of the sensing elements on the APU bleed-air duct and the left wing bleed-air ducts. If the test is correct the BMC transmits a signal to the ECB. Then the ECB moves the APU bleed control valve in the delivery position. The necessary air flow is supplied to the aircraft systems.
NOTE : If the BMC 1 finds a leak in the APU bleed-air ducts, while there
____ is a Main Engine Start (MES) signal from the engines, it ignores the leak signal and commands the ECB to open the APU bleed load valve.
(1) Stop of the APU Bleed-Air Supply To stop the APU bleed-air supply you release the APU BLEED pushbutton switch:
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