Figure 2-48.--Lube and scavenge pump.
system lines in the immediate vicinity of the pump.
LUBE AND SCAVENGE PUMP.--The lube
They sense oil temperatures for the A, B, C, and
and scavenge pump (fig. 2-48) is a six-element,
D sumps and for the TGB; they also provide a
positive-displacement vane pump. Each element
signal to the off-engine electronic controls.
has a wire mesh strainer. One element is used for
lube supply and five are used for lube scavenging.
LUBE SUPPLY FILTER.--The lube supply
The lube supply element supplies oil to the
filter (fig. 2-49) is a duplex filter assembly with
seven main bearings that support the GG assembly
provision for manual selection of either element.
and the PT assembly. These bearings are located
It is mounted on the outboard rail of the engine
in the sumps as follows:
subframe. It is the same type that is used for the
scavenge oil filter. Oil to the GTE enters the
Bearing No. 3R in the A sump
inlet port, flows through the selected element
(outside to inside), and exits through the filter
Bearings No. 4R and 4B in the B sump
outlet port. A bypass (relief) valve in the filter
opens to allow oil to bypass the filter if the filter
Bearings No. 5R and 6R in the C sump
becomes clogged. To make a filter selection, raise
the spring-loaded locking pin, move the selector
Bearings No. 7B and 7R in the D sump
handle until it is in front of the element NOT
being used, and release the locking pin. Make
Scavenge oil enters the pump through the five
certain you engage the pin in the locking slot. A
scavenge oil ports, passes through an inlet screen
drain plug in the bottom of each filter bowl
in each port, and enters the scavenge elements.
permits oil to be drained from the element before
The outputs of the five scavenge elements are
it is removed for cleaning.
connected inside the pump and discharge through
a common scavenge discharge port. This scavenge
LUBE SUPPLY CHECK VALVE.--The
discharge is routed to the duplex filter mounted
lube supply check valve is on the downstream
on the lube storage and conditioning assembly oil
side of the supply filter. It prevents oil in
the tank from draining into the sumps when
The five scavenge elements of the lube and
the GTE is shut down. It opens and flows
scavenge pump scavenge oil from the B, C, and
at a rate of 20 gpm with a maximum differential
D sumps and from the TGB and AGB (A sump).
pressure of 15 psid.
There are five RTDs located in the scavenge oil