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FLOW MEASURING SYSTEM | Up
Aircrew Survival Equipmentman 1 & C - Aviation theories and other practices | Next
Input graph |
I n p u t
PRESSURIZING THE FLOW
MEASURING SYSTEM
The input flow system can only be used with
the chamber at altitude. This system originates at
the air intake on the face of the test stand. When
the input valve (A) is opened, ambient air flows
through this valve (A) to the input vol-o-flow
element. It then flows through the input flow
manometer (2) to the input port (22) inside the
chamber. You can control this flow by opening
or closing the input valve (A).
VENT FLOW SYSTEM
The vent flow system can originate at either
the vent ambient valve (I) or the vent pressure
valve (H). Normally, the vent pressure valve (H)
is used only when the chamber and suit simulator
tank are at sea level. The vent ambient valve (I)
can only be used at altitude. When the vent
ambient valve (I) is used, air is admitted through
an intake port in the rear of the test stand. It then
flows through the vent flow vol-o-flow element
and is indicated on the vent flow manometer (3).
The air then flows to the suit simulator tank.
When the flow selector valve (M) is in the SUIT
SIMULATOR position, air flows to the output
port (23) inside the chamber and continues to the
piezometer (26). You may also direct air from the
suit simulator tank to the output vol-o-flow
element and the output flow manometer (1) by
opening the flutter dampener valve (J). The vent
pressure valve (H) is used only with low-pressure
nitrogen.
To use the flow measuring system, you must
convert the actual liter-per-minute (lpm) flows to
indicated in. H2O. You accomplish this with the
aid of the input, output, and vent flow graphs
supplied with the test stand. See figures 2-12, 2-13,
and 2-14. The actual lpm is found at the bottom
of the graph. Follow the selected lpm line up to
the point where it intersects the air or nitrogen
line. From the point of intersection, follow the
lpm line to the left-hand side of the graph and
determine in. H2O .
Before you start pressurizing the flow measur-
ing system, use the 10,000-foot altitude air line
on the input and output graph to convert 100 lpm
to in. H2O. Open the vacuum control valve (Bl),
ascend to 10,000 feet, and then close the valve
( Bl). Open the output valve (C)to the in. H2O
equivalent of 100 lpm. This flow will be indicated
on the output-flow manometer (l). Now, open the
input valve (A) to the in. H2O equivalent of 100
lpm; this flow will be indicated on the input-flow
manometer (2). Close valves C and A before you
check for leaks. If the system has no leaks, use
the bleed valve (K) and return to sea level. Use
the nitrogen line on the vent flow graph and
convert 150 lpm to in. H2O .
Use the low-pressure regulator to apply 70 psi.
Place the flow selector valve (M) in the SUIT
SIMULATOR position. Open the vent pressure
valve (H) very slowly to the in. H2O equivalent
of 150 lpm. This will be indicated on the vent flow
manometer (3). Now close the vent pressure valve
(H). At this time you should convert 150/lpm to
in . H2O using the air line on the vent flow
graph.
Place the reference selector valve (O) in the
SUIT SIMULATOR position. Now open the suit
simulator reference shutoff valve (R) fully and
place the flow selector valve (M) in the SUIT
SIMULATOR position.
Open the vacuum control valve (Bl) and
ascend to 35,000 feet. Now close down the valve
( Bl) to stabilize the altitude at the same time you
are opening the vent ambient valve (I) to the
equivalent of 150 lpm. This flow will be indicated
on the vent flow manometer (3). Now close the
vent ambient valve (I) and the vacuum control
valve (Bl).
Secure the test stand as outlined in NAVAIR
13-1-6.4. This completes the tests for the nine
different systems. If all the systems checked
out, the test stand will give you outstanding
service.
2-13
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