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|  MIL-P-18526A(SH)
3.3.4.11 Bedplates, bases, table mounts, and brackets shall be cast steel or structural
steel fabricated by welding.
3.3.4.12 Vertical pumps shall be base mounted or center of gravity mounted.
The base
and support bracket shall have provisions for bolting to foundation.
3.3.4.13 Eyebolts, lugs, holes, or other means shall be provided to permit attachment
of lifting gear for lifting the assembled pump, driver, and attached accessories as a com-
plete unit.
3.3.5 Pump bearings.
3.3.5.1 Radial and thrust bearings shall be of the hydrodynamic or rolling contact
type.
3.3.5.2 Rolling contact bearings shall be of the ball type, in accordance with FF-B-171.
Roller bearings may be recommended if use of ball bearings is Impractical. Rolling contact
bearings shall be selected to result in a minimum B-10 life of 10,000 hours, calculated in
accordance with FF-B-171, FF-B-105, or FF-B-187.
3.3.5.3 Hydrodynamic radial bearings may be of the fixed or self alining type, and shall
operate under full fluid film lubrication for all operating conditions, except boundary
lubrication may be used during pump start-up and shut-down. Where the requirement for full
fluid film operation cannot be met, a hydrostatic bearing may be recommended by the manu-
facturer. The hydrostatic bearing shall operate without metal-to-metal contact over the
entire range of the pump characteristic curve.
3.3.5.4 Hydrodynamic and hydrostatic bearing surface and the journal shall be finished
to 32 roughness height rating (RHR) or better.
Bearing installation.
3.3.5.5
3.3.5.5.1 Rolling contact bearings, where used, shall be installed external to pumping
area between coupling and mechanical seal.
3.3.5.5.2 Sleeve bearings shall be split along the axis and shall be arranged to permit
renewal or refitting without removal of the pump rotor from the casing. They shall be fitted
in their housing seat under a light press fit and shall have locking-lips or dowels to pre-
vent circumferential rotation and axial movement. Shells and their seatings shall be machine
finished.
3.3.5.5.3 Bearing housings shall be cast integral with the bracket or secured thereto
in such a manner as to insure alinement, Bearing housing to bracket seats shall be machined
such that the precision of bearing alinement is insured.
3.3.5.5.4 Bearing brackets shall be either cast. integral with the casing, securely
bolted to the casing on a machined shoulder, or held in alinement with the casing by at least
two heavy dowels and securely bolted thereto. The use of bolts alone for securing brackets
is prohibited.
3.3.5.6 Thrust bearings.
.
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3.3.5.6,1 A thrust bearing shall be installed on each pump for counteracting any
unbalanced hydraulic or mechanical thrust in either direction. In this connection considera-
tion shall be given to the fact that rolling, pitching, or list of a ship at sea may intro-
duce thrust loads even though the unit is in hydraulic balance.
3.3.5.6.2 Thrust bearings shall be of the straight ball or roller type, combined
radial and thrust ball or roller type, or plain sliding surface type.
3.3.5.6.3 Thrust bearings of the ball or roller type and their installation shall be
in accordance with FF-B-171 or FF-B-185, as applicable.
Bearing lubrication.
3.3.5.7
3.3.5.7.1 Lubrication of rolling contact bearings shall be in accordance with FF-B-171
or FF-B-185.
3.3.5.7.2 Rolling contact bearing lubrication method shall prevent bearing failure
resulting from overgreasing.
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