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|  MIL-P-18472G(SH)
Rolling contact bearings shall be located in housings
3.2.7.1.1 Locations.
separate from and outside the pumped fluid boundary. Flingers. baffles and non-
rubbing seals shall protect the bearing from entry of water and prevent lubricant
loss.
In vertical pumps, rolling contact bearings shall be located above the
stuffing box or shaft seal. In rigidly coupled and close-coupled pumps, rolling
contact bearings shall be located in the driver only.
Bearing brackets for pumps shall be integral with the
3.2.7.1.2 Brackets.
casing, securely bolted to the casing on a machined shoulder, or held in
alignment with the casing by at least two heavy dowels and securely bolted
thereto, The use of bolts alone for securing brackets is prohibited. The
bearing housing shall be secured to the bracket on machined seats such that
bearing alignment is ensured.
Rolling contact bearings shall be ball
3.2.7.2 Rolling contact bearings.
bearings, unless use of roller bearings is recommended by the contractor and
approved by the design review agency. If approved, roller bearings shall be in
accordance with FF-B-185 or FF-B-187. Ball bearings shall be in accordance with
Ball bearings shall be type 111, class 1 (open) or class 2 (single
FF-B-171.
shield) bearings, or duplex pair type 134 angular contact bearings, in accordance
with the applicable bearing specifications. If noise requirements are specified
(see 3.2.6), rolling contact bearings shall comply with MIL-B-17931.
Rolling contact bearings shall have a minimum L-10
3.2.7.2.1 Fatigue life.
fatigue life of 10,000 hours calculated in accordance with FF-B-171, FF-B-185 or
FF-B-187, as applicable.
3.2.7.2.2 Lubrication.
Rolling contact bearings shall be grease-lubri-
cated, except bearings in turbine drivers may be oil-lubricated in accordance
with MIL-T-17523. Oil-lubricated bearings shall be provided means to ensure
adequate lubrication immediately when the shaft starts to turn, regardless of
the length of time the pump unit is idle. Grease-lubricated rolling contact
bearings shall not have a DN value greater than 200,000 (where D = bearing bore
diameter in millimeters; N = revolutions per minute).
3.2.7.2.3 Operating temperature . Rolling contact bearing operating
temperature (measured on the bearing outer ring) shall not exceed 194 degrees
Fahrenheit
at any operating condition up to the specified maximum ambient
and pumped fluid temperatures. A straight hole with plug shall be provided in
each rolling contact bearing housing to permit insertion of a thermocouple probe
to contact the bearing outer ring circumference. Externally supplied cooling
liquid or externally induced forced draft shall not be required to meet the above
conditions.
3.2.7.2.4 Relubrication. Rolling contact bearings shall be relubricated
without bearing removal, and shall not require frequent relubrication if the
pump is not operated over an extended period of time. Bearing lubrication and
drain connections shall be located so as to force new grease into the bearing
and direct old displaced grease out the drain. The bearing relubrication
procedure shall not cause bearing failure due to overgreasing, and shall be
accomplished with the pump unit secured.
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