
Pratt & Whitney Rzeszów S.A.
MAINTENANCE MANUAL
PZL-10W ENGINE
1992.08.28
73-12-02
Page 1
Export Control Classification: PL/UE 9E999
CHECK VALVE - DESCRIPTION AND OPERATION
1.
Description (Dwq 1).
The check valve protects the diaphragm of the power turbine rotational speed limiter against the damaging by
the impulse of the air pressure going from the engine combustion chamber to the drainage main at the
moment when the drain valve (see 73-02-00, Dwg 2) opens at the engine stopping.
The check valve is installed in the drainage main lines (see 73-02-00, Dwg 1 ) between the T-connection (73-
12-01, item (4)) and the pipe draining the drained fuel from the power turbine rotational speed limiter (see
Dwg 2).
The check valve consists of a casing, in which there is a ball secured against a falling out by the spring ring
lock and the nut secured by the wire ring.
2.
Operation.
Under the influence of the air pressure impulse from the engine combustion chamber, the ball moves to the
casing seat and closes the diaphragm space of the power turbine rotational speed limiter protecting the
diaphragm against rapid increase of the pressure.
After the pressures stabilizes in the drainage main, the ball comes back to the neutral position opening the
way for the fuel drain from the power turbine rotational speed limiter.