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A 737-300/400/500MAINTENANCE MANUAL
1.
RAM AIR INLET DEFLECTOR DOOR
2.
RAM AIR INLET MODULATION PANEL
3.MIXING CHAMBER
4.WATER SEPARATOR 35`F CONTROL
5.RAM AIR DUCT
6.WATER SEPARATOR
7.TURBOFAN VALVE
8.AIR CYCLE MACHINE
9.SECONDARY HEAT EXCHANGER
10.PRIMARY HEAT EXCHANGER
11.
PACK VALVE
12.
MIX VALVE
13.
RAM AIR ACTUATOR
14.
TURBOFAN
15.
RAM AIR EXHAUST DUCT
16.
RAM AIR MODULATION SYSTEM CONTROL CABLES
17.
WATER SEPARATOR 35`F CONTROL VALVE
18.
PNEUMATIC SUPPLY DUCT
19.
ISOLATION VALVE
20.
RAM AIR TEMPERATURE SENSOR
SEE A
21.
WATER SPRAY INJECTOR SYSTEM
14
13 10 15 FROM APU
11
1298 1420
7 1521
6
5
4
13
2
1
16
5 7
10 9 12 11 20
8
6 17
4 18 21
19
3. (LEFT SIDE ONLY)
A
Cooling Air and Ram Air Equipment Location
Figure 1
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BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
737-300/400/500MAINTENANCE MANUAL
AIR CYCLE SYSTEM - DESCRIPTION AND OPERATION
____________________________________________
1. General_______
A. Air conditioning cooling is provided by two air cycle systems. The system also removes excess moisture from the air.
B. Air cycle system equipment is contained in equipment bays located on either side of the airplane centerline at the underside of the center fuselage (Fig. 1).
C. In each air cycle system air is metered through the Pack (a flow control) Valve. The cooling devices used in the air cycle system consists of a primary heat exchanger, a secondary heat exchanger, and an air cycle machine. The heat exchangers are of the air-to-air type, with heat being transferred from the air going through the air cycle system to air going through the ram air system. The air cycle machine consists of a turbine and a compressor. Air passing through the secondary heat exchanger and expanding through the turbine drops in temperature as the energy is extracted. The expanding air releases energy to drive the compressor.
D. Protection of the air cycle machine is provided by two thermal switches. One thermal switch senses compressor discharge temperature. The other thermal switch senses turbine inlet temperature. Actuation of either thermal switch will cause the pack valve to close.
E. As the air cools, its moisture content condenses. The moisture is atomized so finely however, that it will stay in suspension without a moisture removing device. The water separator collects this atomized moisture and removes it from the air cycle system air after it has left the air cycle machine.
F. Moisture entering the water separator is kept from freezing by a 35°F control system. A 35°F sensor in the water separator and a 35°F controller regulate the 35°F control valve in a duct between the primary heat exchanger exit and the water separator inlet. The valve opens to add warm air if the turbine discharge air temperature is sensed to be 35°F or less.
G. Water collected by the water separator is sprayed into the ram air inlet duct, upstream of the pack heat exchangers, through a water spray injector. The spray augments heat exchanger cooling capacity and improves cooling system performance. When the air conditioning pack is shut off, water collected in the water separator will be discharged overboard.
2. Pack Valve (Fig. 2)__________
A. Bleed airflow through each of the air cycle systems is controlled by the pack valve. This valve controls the mass flow so that a nearly constant volumetric flow (cfm) is supplied to the air conditioning pack.
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本文链接地址：737-300 400 500 AMM 飞机维护手册 空调 AIR CONDITIONING 1(123)
