Figure 4.27. Interstage Bleed System, External Components.
When the slide valve is closed, it follows then that the bleed
band will be closed. This is accomplished by a buildup of pressure
on the top side of the relay valve diaphragm which forces the relay
valve down, closing off the overboard vent. With the overboard vent
closed, the P3 pressure is now routed into the actuator piston
assembly to move upward. This causes the bleed band to close around
the compressor bleed ports.
The entire sequence of operation is controlled by the fuel
control which senses gas producer (N1) speed, fuel flow and pilot
demand, therefore ensuring proper opening and closing of the
interstage air bleed.
4.19.
ANTIICING SYSTEM
The engine antiicing system, shown in figure 4.29, supplies
hot air, under pressure, to prevent icing of the inlet housing areas
and inlet guide vanes when the engine is operating under icing
conditions. Pressurized hot air from the air diffuser flows through
the holes in the trailing edge of the diffuser vanes and collects in
the bleed air diffuser manifold, where it is passed to an external
bleedair manifold located at the 1 o'clock position on the diffuser
housing. An elbow and tube are connected to the external bleedair
manifold
127
Previous Page
