In leveling a pump unit, first use small metal
wedges (fig. 6-29) and then place metal blocks and
shims close to the foundation bolts. In each case, space
the supports directly under the part carrying the most
weight and close enough to give uniform support.
Leave a gap of about 3/4 to 1 inch between the baseplate
and the foundation for grouting with cement. (Grout is
a mixture of cement, sand, and water, making up a thin
mortar.) Figure 6-30 shows a baseplate of a pump unit
grouted to the foundation, making angular alignment.
Adjust the supports or wedges until the shafts of
the pump and the driver are level. Use a level to check
the coupling faces and suction and discharge flanges to
ensure that they are plumb and level. Correct the
positions by adjusting the supports or wedges as
In addition to checking for parallel alignments,
you should check the angular alignment between the
pump shaft and the drive shaft. Insert a taper gauge or
feeler at four points between the coupling faces, as
shown in figure 6-31. The points should be spaced at
90-degree intervals around the coupling. When the
measurements are all alike and the coupling faces are
the same distance apart at the four points, the unit is in
angular alignment. Correct any misalignment by
adjusting the wedges or shims under the baseplate.
Remember that an adjustment in one direction can
disturb adjustments in another direction.
Figure 6-29.Wedging a baseplate.
Figure 6-30.Baseplate of a pump unit grouted to the
Figure 6-31.Making angular alignment.
Many of the pumps used by the Navy are
centrifugal pumps. Figure 6-32 shows a typical
installation of a centrifugal pump. There are two types
of assembly in which centrifugal pumps are delivered.
One group has the pump and the driver mounted
on a common baseplate at the factory. The other group
has only the pump mounted at the factory, so the driver
must be positioned at the place of installation. In the
former group, factory alignment may not have been
maintained, as all baseplates are somewhat flexible.
Therefore, you must realign the unit after it has been
leveled on the foundation. To do this, first disconnect
the coupling halves. Then follow the same alignment
steps that have just been given. After completing these
steps, reconnect the coupling and check it again for
parallel and angular alignment. To install a centrifugal
pump of the second group, you have a little extra work.
After you have placed the baseplate with the pump on
the foundation, you level, align, and bolt it. Next, place
the driver on the baseplate according to the blueprints.
Adjust the position of the driver and shim it up until the
pump and driver half couplings are aligned. Then bolt
it securely and proceed as in the other installation.
After you have correctly aligned the pump, tighten
the foundation bolts evenly, but not too firmly. Then
completely fill the baseplate with grout. Try to grout
the leveling pieces, the shims, or the wedges in place.
Foundation bolts should not be fully tightened until the
grout has hardened, usually about 48 hours after
After the grout has set and the foundation bolts
have been properly tightened, the pump should be