777 AMM 飞机维护手册 发动机引气 Engine Air PW 777 AIRCRAFT MAINTENANCE MANUAL(13)

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9:00 and 11:00 positions. The upper valve is aft of the 2.9 bleed valve.
Functional Description
The valves are poppet-type valves. Springs hold each valve open. PS3 air pressure closes the valves.
When the valve is fully open, a position indicator pin extends above the valve body.
The right side valve supplies air to the HPT 2nd stage vanes, the LPT 3rd through 5th stage vanes, and the No. 3 bearing buffer air cooler.
The upper left side valve supplies air to the HPT 2nd stage vanes and blades and the LPT 3rd through 5th stage vanes.
The lower left valve supplies air to only the HPT 2nd stage vanes.
Training Information Point
All of the valves are interchangeable.
EFFECTIVITY BEJ ALL  75-25-00 
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D633W101-BEJ  Jan 05/2004 

 

AIR -TVBC SYSTEM -TVBC AIR SHUTOFF VALVES

EFFECTIVITY BEJ ALL  75-25-00 
Page 9 
D633W101-BEJ  Sep 05/2003 

AIR -TVBC SYSTEM -TURBINE VANE COOLING (TVC) ACTUATOR AND VALVE

Purpose
The TVC air valve actuator moves the air valve to control 12th stage airflow to the HPT 2nd stage vanes.
Location
The TVC air valve actuator and air valve are on the HPC case at the 2:00 position. The valve is under the engine main fuel supply line.
TVC Air Valve Actuator
The EEC controls the actuator torque motor. Servo fuel pressure moves the actuator piston.
If a fuel seal leak occurs, a drain tube sends the fuel leakage to the engine/strut overboard drains.
A tube supplies fan air to the actuator for cooling.
TVC Air Valve
The TVC air valve is a butterfly-type valve. A spring holds the valve open. The TVC air valve actuator moves the rod to modulate the valve.
Training Information Point
No rigging is necessary.
EFFECTIVITY BEJ ALL POST SB 777-71-0032  75-25-00 
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D633W101-BEJ  Jan 05/2004 

 

AIR -TVBC SYSTEM -TURBINE VANE COOLING (TVC) ACTUATOR AND VALVE

EFFECTIVITY BEJ ALL POST SB 777-71-0032  75-25-00 
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D633W101-BEJ  Jan 05/2004 

AIR -TVBC SYSTEM -TURBINE COOLING AIR (TCA) THERMOCOUPLE PROBE

Purpose
The turbine cooling air (TCA) thermocouple probe monitors the turbine cavity seal temperature. The EEC uses the temperature data to control the TVBC and thrust balance control systems.
Location
The thermocouple probe is on the HPT case at the 10:00 position.
Functional Description
The probe has two thermocouples. Each thermocouple sends a signal to an EEC channel.
Training Information Point
Be careful when you remove the probe. The probe has an angular shaft which bends up.
EFFECTIVITY BEJ ALL  75-25-00 
Page 12 
D633W101-BEJ  Sep 05/2003 

 

　
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