Figure 2-49.--Lube supply filter.
C- AND D-SUMP CHECK VALVE.--This
coolant passes from the MRG lube oil cooler
check valve is in the lube supply line to the C and
through temperature control valves and through
D sumps. It isolates the C and D sumps from the
the inside of the tubes. The synthetic lube oil
GG lube oil system when an external lube supply
passes around the outside of the tubes. The oil
and scavenge system is used for the PT. Both the
is discharged from the oil cooler back to the oil
C- and D-sump oil supply lines and scavenge lines
tank. To gain direct access to the inside of the
have fittings to connect an external lube system
coolant tubes for cleaning, remove the end domes.
for the PT. During normal engine operation, the
lube oil pump supplies lube oil to the C and D
AIR/OIL SEPARATOR.--The
air/oil
sumps. The check valve opens at 2 psid.
separator has a fabricated sheet metal impeller
with a cast aluminum housing. It prevents
SCAVENGE OIL FILTER.--The duplex
excessive oil loss from venting oil vapor over-
scavenge oil filter differs from the lube supply
board. All sumps are vented to the air/oil
filter only in its mounting position. The scavenge
separator. The sump air is vented to the exhaust
filter is located on and is part of the LOSCA. See
duct after passing through the separator. Oil is
figure 2-47.
collected on the inside of the impeller as the oil-
laden sump air passes through the separator.
SCAVENGE OIL CHECK VALVE.--The
Small holes in the segments of the impeller allow
check valve is between the scavenge filter and the
the collected oil to be discharged to the separator
oil cooler (heat exchanger). It prevents oil in the
outer housing. Vanes on the housing wall are
scavenge lines from draining back into the sumps
used to collect and direct the oil to the separator
and gearbox while the engine is shut down. It
outlet where it is returned to the gearbox. To
functions the same as the lube supply check valve.
prevent oil and oil vapors from escaping past the
end of the impeller, the separator has two
OIL COOLER.--The oil cooler is a shell-tube
labyrinth seals, with the cavity between the
assembly (see fig. 2-47). The coolant is main
two seals pressurized with eighth-stage ejector
reduction gear (MRG) lube oil (2190 TEP). The
air.
2-43
