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ALL ú ú 01 Page 703 ú Jul 15/97
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
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737-300/400/500MAINTENANCE MANUAL
FLIGHT CREW OXYGEN SYSTEM - DESCRIPTION AND OPERATION
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General
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A. The flight crew oxygen system is a diluter-demand type system which supplies supplemental and protective breathing oxygen to the flight crew stations (Fig. 1).
B. Oxygen is supplied by a high pressure cylinder with a pressure regulator and a pressure transducer that is close-coupled to the cylinder, a system shutoff valve, a distribution manifold, and individual mask/regulators (with mask storage boxes at the captain's and first officer's stations).
C. A high pressure indicator on the aft overhead panel receives an electrical signal from the pressure transducer.
D. The flow of low pressure oxygen to each individual mask is controlled by the mask/regulator and (when installed) the mask storage box. The system can be used at any altitude.
E. The system includes pressure relief devices for protection against too much pressure.
F. Oxygen servicing is accomplished by cylinder replacement with a fully
charged cylinder.Crew Oxygen Cylinder Assembly
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A. The crew oxygen cylinder assembly (Fig. 2) supplies the gaseous oxygen for the crew oxygen system. The cylinder is installed on the forward right sidewall of the forward cargo compartment. The cylinder, when filled to a pressure of 1850 psig, has a capacity equal to 39 cubic feet of gaseous oxygen at 760 millimeters HG absolute and 70°F.
B. The cylinder assembly includes a slow-opening shutoff valve, an oxygen pressure indicator, and a safety relief device which breaks before pressure can damage a valve or the cylinder, tubing, or components. The safety relief device has an outlet port with a frangible disk that will break, in the event of too much pressure. This permits the cylinder to vent the oxygen overboard through a vent in the airplane skin.
Cylinder Coupling Assembly
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A. A cylinder coupling assembly is installed on the outlet fitting of the cylinder (Fig. 2). It has mounting connections that are close coupled for the pressure transducer and pressure regulator.
B. A brush-like wire element that is approximately 3 inches long is inserted tightly into the coupling assembly. This wire element functions as a thermal compensator to prevent oxygen temperature extremes when the system is being used.
Pressure Regulator
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A. The pressure regulator (Fig. 2) connects to the cylinder coupling assembly and decreases cylinder pressure of 60 to 1850 psi to an outlet pressure of 60 to 85 psi. A pressure relief valve is included in the regulator to protect the system downstream from the regulator. The relief valve is set to relieve at approximately 100 psi and discharges into the forward cargo compartment.
EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. ú
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ALL ú ú 01 Page 1 ú Jul 15/96
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A 737-300/400/500MAINTENANCE MANUAL
MASK STORAGE BOX WITH MASK/REGULATOR (FIRST OFFICER'S STATION)
(CAPTAIN'S STATION)
Flight Crew Oxygen System Component Location
Figure 1
EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. ú 中国航空网 www.aero.cn 航空翻译 www.aviation.cn 本文链接地址：737-300 400 500 AMM 飞机维护手册 氧气 OXYGEN(7)
