B. The control cable is a pre-lubricated flex cable continued in a hard
sheath, in which most of the control cable has shields for protection.
The control cable, which is connected between the TCC air valve actuator
and the TCC air shutoff valves, includes a cable and a linkage which
includes an idler arm and a turnbuckle.
C. When the control cable is pulled forward, the idler arm on the shutoff
valve for the HPT case cooling air turns, which pushes the lever arm on
the HPT case cooling air shutoff valve upward, and pulls the turnbuckle
forward.
10. Turbine Vane and Blade Cooling Air Valve (Fig. 1)
________________________________________
A. The TVBCA valve controls the flow of 12th-stage HPC air to the HPT
2nd-stage turbine vanes and blades.
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B. There are two TVBCA valves installed on the HPC aft case at the 3 and
9:30
o'clock positions. Each air valve includes a flange mounted inlet port, two flange mounted outlet ports (blade and vane), one threaded air signal port, a visual position indicator, and a poppet connected piston.
C.
The spring loaded, normally open valve is operated to the closed position when air pressure, from the TVBCA valve solenoid, goes in the air signal port and applies pressure on the piston. As a result, the poppet moves with the piston to close the shutoff valve and to stop airflow to the blade and vane outlet ports and between the blade and vane outlet ports. The visual position indicator pin is retracted below the surface of the indicator body when the shutoff valve is fully closed. When air pressure is removed, the shutoff valve moves to the fully open position and the visual position indicator pin extends above the surface of the body.
11. Turbine Vane Cooling Air Valve (Phase 3 only, Fig. 1)
______________________________
A. The TVCA valve controls the flow of 12th-stage HPC air to the HPT 2nd-stage turbine vanes.
B. There is one TVCA valve installed on the HPC aft case at the 2 o'clock position. The valve includes a flange mounted outlet port (vane), one threaded servo port, and a visual position indicator.
C. The valve is a normally open, pneumatically operated, poppet-type air shutoff valve. 15th-stage HPC air is used to close the valve and stop the airflow to the vane outlet port. The visual position indicator pin is retracted below the surface of the indicator body when the shutoff valve is fully closed. When air pressure is removed, the shutoff valve moves to the fully open position and the visual position indicator pin extends above the surface of the body.
12. TVBCA Valve Solenoid (Without Phase 3, Fig. 1)
____________________
A. The solenoid, which is an electrically operated, single coil, pneumatic type solenoid valve, supplies pneumatic servo pressure to operate the right and left TVBCA valves.
B. The solenoid is assembled to the same valve housing with the solenoid for the left HPC secondary flow control valve, and is installed on the left side of the common valve housing. The solenoid is installed on the aft face of the intermediate case at the 10 o'clock position.
C. The solenoid is fail-safe to stop pneumatic servo pressure to the two TVBCA valves which cause the shutoff valves to open.
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