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8. Compressor Discharge Temperature Bulb (Fig. 2)
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A. A temperature bulb is installed in the outlet duct of the ACM compressor. The bulb provides flight deck indication of compressor discharge temperature on EICAS.
9. Compressor Discharge Overheat Switch (Fig. 2)
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A. The compressor discharge overheat switch is mounted on the outlet duct from the ACM compressor. If the compressor outlet temperature exceeds 425° F (218° C), the switch closes, causing the flow control and shutoff valve to close and the SYS FAULT light on the cabin temperature control panel to come on. The pack remains off until the PACK RST switch on the cabin temperature control module is pressed.
10. Water Separator (Fig. 2)
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A. The water separator contains a fabric coalescer, a vortex generator, a collector-drain section, and a pressure relief valve. Water-laden air enters the water separator and water particles are formed into larger droplets as they pass through the coalescer. The air is then swirled as it passes through the vanes of the vortex generator where the droplets are centrifugally forced to the collector to be drained from the water separator. The pressure relief valve allows the air to bypass the coalescer if it becomes clogged. Ice formation on the coalescer is prevented by controlling the air temperature into the water separator with the turbine bypass valve.
11. Water Aspirator (Fig. 2)
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A. The water aspirator is mounted at the heat exchanger cooling air inlet and injects water from the water separator into the air stream. Air tapped from the ducting upstream of the compressor inlet is used to induce water flow through the aspirator. The drain line of the water separator is connected to the water inlet port of the aspirator.
12. Pack Discharge Overheat Switch (Fig. 2)
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A. The pack discharge overheat switch in each pack is mounted on the duct just downstream from the water separator. The pack discharge overheat switch is wired in parallel with the compressor discharge overheat switch. If pack outlet temperature exceeds 185° F (85° C), the switch closes, causing the flow control and shutoff valve to close and the SYS FAULT light on the cabin temperature control module to come on. The pack remains off until the PACK RST switch is pressed.
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BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
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747-400
MAINTENANCE MANUAL
13. Airflow Sensor (Fig. 2)
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A. An airflow sensor is installed in each conditioned air duct downstream of the water separator. The airflow sensor consists of an inductive pickup and a permanent magnet rotor coupled to a turbine. The sensor outputs an ac signal to the signal conditioner when the turbine blades are spun by the flow of conditioned air. The ac signal frequency increases with increasing airflow.
14. Signal Conditioner
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A. The signal conditioner converts the ac outputs of all three airflow sensors to dc signals which are sent to the pack temperature controllers for display on EICAS. The signal conditioner is attached to structure in the right wing gear wheel well.
15. Catalytic (Ozone) Converter (Fig. 2)
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A. A catalytic (ozone) converter is installed in-line with each pack supply duct to minimize ozone entry into the airplane. A container is located upstream of each pack flow control and shutoff valve.
16. Water Collector (Fig. 2)
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A. A water collector is installed in each pack. The water collector is installed between the secondary heat exchanger and the turbine inlet to the ACM. The water that is collected is drained through a line from the collector to a drain port on the ram air exhaust.
B. A set of swirl vanes at the inlet of the collector forces the water to the outer walls of the duct. Downstream at a collector section, the air flow with the water is scavenged off into a diffuser section where the flow velocity is reduced to allow the entrained water to drop out of the air stream. The water falls to a drain port by gravity where it is bled out of the collector.
17. Operation (Fig. 3)
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A. Functional Description
(1)
The air conditioning packs are connected in parallel, and operate independently. They are supplied with air from the pneumatic bleed air manifold at approximately 45 psi.
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本文链接地址：747-400 AMM 飞机维护手册 空调 AIR CONDITIONING 1(176)
