Transfer System
The transfer system discussed here is a typical
arrangement using three transfer pumps and two
centrifugal purifiers in each pump room. See figure 4-
2.
The suction header, common to all three transfer
pumps, is connected directly to the port and
starboard transfer-main branch headers. The two
valves installed in the suction header, one port and
one starboard, permit the transfer pumps to take
suction either from the port or starboard storage
tanks independently or from both at the same time.
Three pump inlet lines connect the common
suction header with the suction side of the transfer
pumps. Each line contains an inlet valve and a
compound gage.
The transfer pumps discharge into a common
discharge header. Each pump discharge line contains
a test connection, pressure gage, one-way check
valve, and a discharge valve.
Two cutout valves are arranged in the discharge
header (one between each pump discharge line) to
enable
both
purifiers
to
be
in
operation
simultaneously, using any two of the three transfer
pumps. For instance, when pump 1 is aligned with
purifier No. 1, either pump 2 or pump 3 can be
aligned with purifier No. 2. When pump 3 is aligned
with purifier No. 2, either pump 1 or pump 2 can be
aligned with purifier No. 1. Never align more than
one transfer pump to only one purifier.
This valve arrangement also permits two
separate transfer operations to be performed
simultaneously. For example, if pump 1 is aligned
with purifier No. 1 to top off a service tank, pumps 2
and 3 can be used to transfer JP-5 from forward to
aft, reclaim fuel, and so forth. The same applies for
pumps 1 and 2 when pump 3 is being used with
purifier No. 2.
Purifiers are bypassed for all transfer operations
except when service tanks are being filled. The
bypass lines extend off the extreme ends of the
transfer-pump discharge header and are connected to
the transfer main. Cutout valves separate the bypass
lines from the discharge header. Two valved
crossovers (one port and one starboard), interconnect
the bypass line with the common suction header of
the transfer pumps. The cross-overs are used to align
the transfer system for pumping JP-5 from port to
starboard, or vice versa. The purifier bypass line is
also
used
when
transferring
JP-5
from
Figure 4-2.—Typical transfer system.
4-4
