(4)  
A description of the flow-control-and-shutoff-valve components:

 (a)  
The valve flow section

 1)  The valve flow section is a venturi-type tube assembly. A butterfly plate, attached to a shaft, is in the assembly. The valve flow section measures 4 inches in diameter and
 14.25 inches long. All other valve components are attached to the valve flow section.
 (b)  
The mechanical-manual-override valve

 1)  The mechanical-manual-override valve supplies a way for the flow control valve to be manually closed. It has two valve seats, a ball, and a manual override actuator.

 (c)  
The pneumatic actuator

 1)  The pneumatic actuator is the mechanism that controls the butterfly plate in the valve flow section. The pneumatic actuator has an actuator housing assembly and an actuator linkage assembly.
 2)  The actuator housing includes an actuator diaphragm that divides the pneumatic actuator into two chambers. Chamber N bleeds to the mechanical manual override valve. The ambient-pressure-sensing chamber bleeds to ambient. The ambient-pressure-sensing chamber has a spring to push the actuator diaphragm against the chamber N.
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A

757
MAINTENANCE MANUAL

SEEA
FWD
ALTITUDE
ADJUSTMENT H

SOLENOID
(INNER SCREW)

VALVE ASSY B ELECTRICAL MANUALSLAVE SERVO VALVE BLEED NOZZLE CONNECTION
ADJUSTMENT L  OVERRIDE CLOSED STOP
ADJUSTMENT K VISUAL ACTUATOR ADJUSTMENT POSITION INDICATOR
TESTPORT D MANUAL PNEUMATICCONTROL
ADJUSTABLE ACTUATOR
ROD
ORIFICE F
ASSEMBLY (NORMAL FLOW) CAM ASSEMBLY
SEE C CLOSED POSITION SWITCH ELECTRICAL CONNECTOR
ADJUSTABLE ORIFICE G TEST PORTS
SOLENOID VALVE
ASSY A ELECTRICAL
CONNECTION

MANUALSEE B OVERRIDE
VALVE
ELECTRO-MAGNETIC ACTUATOR
CONTROL VALVE  BODY ASSY
ELECTRICAL CONNECTOR
A

Flow Control and Shutoff Valve
Figure 3 (Sheet 1)

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A

757
MAINTENANCE MANUAL

ASSY
TEST PORT R
J
INLET PRESSURE SENSING TUBE ASSY
THROAT PRESSURE SENSING TUBE ASSY

Flow Control and Shutoff Valve
Figure 3 (Sheet 2)

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A
757
MAINTENANCE MANUAL

ZERO DIFFERENTIAL
PRESSURE VALVE

ADJUSTABLE ORIFICE F(NORMAL FLOW)
ACTUATOR
CHAMBER M
SONICLEVER NOZZLE CHAMBER C
SUPPLYNOZZLE ANEROID
ADJUSTABLE
CHAMBER D
ORIFICE E

(HIGH FLOW)
FLAPPER TORQUE
ADJUSTMENT MCHAMBER Q SLAVE SERVOMOTORVALVE
SOLENOID VALVE A
ADJUSTMENT L ADJUSTABLE ORIFICE GBLEED NOZZLE(MINIMUM AIRFLOW SINGLEPORT PACK OPERATION)
ELECTROMAGNETIC
BLEED NOZZLE
ADJUSTMENT K

ALT ADJUSTMENT H CONTROL VALVE POPPET
VALVE
SOLENOID
LATCH
REFERENCEBALL VALVE
PRESSURE

ASSEMBLY
REGULATOR
MANUAL
CLOSED STOPCONTROL
ROD
CLOSE
ADJUSTMENT
SOLENOID VALVE B
CHAMBER N
PNEUMATIC
ACTUATOR
THROAT PRESSURE
BALL
SENSING PROBE AMBIENT
VENTOPEN
BUTTERFLYAIR FLOW
PLATE

MANUAL OVERRIDE
ACTUATOR
VALVE BODY

INLET PRESSURECAM
CLOSED VISUAL POSITIONSENSING PROBE
INDICATOR
SWITCH

POSITION
OPEN CLOSE NOTE: ALL VENTS TO AMBIENT
MECHANICAL MANUAL OVERRIDE VALVE
Flow Control and Shutoff Valve Operation
　
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