• LOADING FROM A TRUCK ON THE DOCK.
Rig a direct line from the truck to the filling
connection. With this method, a pump on the truck is
used to boost the oil from the truck to the filling
connection.
CAUTION
When loading from struck on the dock, use
caution to ensure that the pressure from the
truck to the lube oil system is not enough to
cause damage to hose, piping, or pumps.
When the system is taking on lube oil, a vent is
not necessary, because the system is vented through
the tank to the overflow tank. The valves from the
tank to the overflow tank are locked open during this
operation. To allow for expansion, tanks should not be
filled beyond 90% capacity.
Figure 6-2.—Typical rotary-screw lube oil pump.
Lube Oil Pumps
Numerous lube oil pumps are installed on Navy
ships, and it would be nearly impossible to cover each
one. This manual will cover an older pump, the De
Laval 31P156.
The De Laval 31P156 is a vertical, single-stage,
positive displacement, rotary-screw pump (figs. 6-2 and
6-3). The pump consists of a power rotor (which moves
the oil), two idler rotors (for sealing), the housing,
thrust elements, shaft packing, and piping con-
nections.
When the pump is started for the first time or
after a long period of idleness, follow the instructions
for initial starting, given below.
Figure 6-3.—Rotary-screw pump (cutaway).
6-3
