(c)
A door latch, which operates pneumatically and holds the container door closed until the pressure in the supply lines is
1.38 bar (20.0152 psi).
To open the door manually, release the latch assembly with the
manual release tool. The manual release tools are kept at the
cabin attendant stations.
(d)
A flexible hose, which connects the oxygen distribution system to the inlet port. The inlet port has a filter to stop unwanted materials, which could cause the equipment to operate incorrectly.
(e)
A flexible hose, which supplies oxygen to the door latch and the regulation and distribution device.
(f)
The distribution unit, which supplies oxygen at the correct rate. At cabin pressure altitude of less than 10000 ft. (3048 m) there is no flow. There is an outlet port and initialization mechanism for each mask. Oxygen is only supplied to the masks that are pulled down. The other masks in the same container (that are not pulled down) do not operate. The oxygen supply to the mask is started when the release pin is pulled out by the lanyard, which is attached to the mask. A pull force of maximum 10 lb (4.5359 kg) is necessary to remove the release pin. The pull angle can be a maximum of 120 degrees about the vertical direction in relation to the container lid.
(g)
The continuous-flow oxygen mask is the aronasal phase-dilution type, it has:
-
A plastic mask that covers the mouth and nose.
-
A reservoir bag with a capacity of 1000 cm3 (61.02 in.3) when it is inflated. There is an illustration on the bag to show you how to use the mask.
Emergency Oxygen Container - Example
Figure 008
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CES
Emergency Oxygen Container - 2 Mask
Figure 009
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Aug 01/05
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-An elastic strap to hold the mask in position.
-A lanyard, which connects the release pin to the mask.
-
An oxygen supply tube, which is connected to the regulation and distribution device.
-
An oxygen flow indicator, which is the green part of the reservoir bag. The flow indicator inflates when there is a flow of oxygen.
F. Bleed/Vent Valve 7503WR
(Ref. Fig. 003)
The bleed/vent valve is installed in the main distribution line between
FR25 and FR26 above the cabin ceiling.
The bleed/vent valve has two functions:
(1)
The vent function releases the unwanted pressure in the system if there is a leak through the oxygen regulators. This makes sure that the oxygen masks only release when the system operates.
(2)
The bleed function releases the ambient air from the supply lines after the system is started. The valve opens for approx. 15 to 25 seconds and closes again. This removes the ambient air from the lines and let the oxygen masks supply with pure oxygen.
G. Main-Distribution-Line Shut-Off Valves 7550WR510 and 7553WR460
(Ref. Fig. 006)
The main-distribution-line shut-off valves are installed upstream before
the rim release area:
-
For 7553WR460: in the ceiling supply line between FR46 and FR47
-
For 7550WR510: in the underfloor supply line between FR51 and FR52. The main-distribution-line shut-off valves are pneumatically controlled so that oxygen is not supplied to a damaged main supply line. In normal operation the main-distribution-line shut-off valves are open. They close if the flow rate increases to a value more than max. 390 l.min (103.0262 USgal.mn). A valve stays closed until the pressure difference across the valve is less than 1.0 bar (14.5037 psi).
5. Operation/Control and Indication
________________________________
When the cabin pressure decreases the oxygen regulators open and the
low-pressure system is pressurized:
-
The system is bled through the bleed/vent valve.
-
The pneumatically controlled door latches let the oxygen container doors open and the oxygen masks fall down.
-
The passenger pulls the mask to his face, which releases the oxygen flow release pin.
-Oxygen is supplied in a controlled flow to each mask, related to the cabin pressure altitude,
-
The flow indicator shows that there is a flow of oxygen.
If an engine turbine bursts and damages a main oxygen supply line:
-
The appropriate main-distribution-line shut-off valve 7550WR510 or
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