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|  MIL-P-18547A(SHIPS)
3.6.7.2.1 Thrust bearings may be of the straight thrust ball or roller type, combined ratial and thrust
ball or roller type, or plain sliding surface type.
3.6.7.2.2 Thrust bearings of the ball or roller type, and the installation thereof, shall be in accordance
with FF-B-171, FF-B-185 and FF-B-187, as applicable.
3.6.7.2.3 Sliding surface thrust bearings shall be as approved for design and application by the bureau or
agency concerned.
3.6.7.3 Bearing installation. -
3.6.7.3. 1 Where sleeve bearings are fitted in closed heads they may be of the solid bushing type secured
by pins or keys. For independent bearings on brackets fitted at stuffing box ends, the sleeve bearings shall be
split along the axis. All sleeve bearings shall be so arranged to permit renewal or refitting without removal
of the pump rotor from the casing, and they shall be securely fitted to prevent axial movement.
3.6.7.3.2 For either internally or externally mounted bearings, the bearing housing shall be cast integral
with the pump case or bearing bracket, or secured thereto in such a manner as to insure alignment.
3.6.7.3.3 Bearing brackets shall be either cast integral with the 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.
3.6.7.3.4 The number, type and arrangement of bearings shall be as approved by the bureau or agency
concerned.
3.6.7.4 Bearing lubrication. -
3.6.7.4.1 Ball, roller or sleeve bearings may be lubricated by the fluid pumped, provided the bearing
housings are so designed that there are no pockets, which may act as water, sediment, or sludge traps, and a
continuous circulation of fresh oil is provided through such bearings.
3.6.7 .4.1.1 Bearings lubricated by the fluid pumped shall be required to operate in a manner satisfactory
to the bureau or agency concerned throughout the test specified in 4,5.4.1, however, deterioration to a point
requiring replacement of the bearings immediately after the test will not disqualify the bearings,
3.6.7 .4.1.2 Steam turbine driven pumps may be retained in a stand-by condition for long periods of time,
that is with just enough steam through the turbine to keep the rotating element turning slowly, ready to be
speeded up to full speed at any time. The drawings and manuals shall state the minimum speeds at which the
pump can be operated continuously and safely.
3.6.7.4.2 Externally mounted ball or roller bearings shall be lubricated in accordance with FF-B-171,
FF-B-185 and FF-B-187, as applicable.
3.6.8 Piping and valves. -
3.6.8.1 Suction and discharge connections shall be flanged for mating with flanges specified for the serv -
ice in accordance with MIL-STD-438 or MIL-STD-777 as applicable. Suction and discharge pressure gage
connections shall be flanged; the flange connections shall be in accordance with Drawing B-214.
3.6.8.2 Gland seal piping, shall be extra heavy steel pipe, 1/8 inch iron pipe size (i.p. s.), with steel valves
and steel fittings. Valves shall have socket weld ends. Fittings shall be flareless mechanical "bite" type.
Mechanical "bite" type fittings with SAE straight threads and "O" rings for boss mounting may be used for
root connections. Mechanical "bite" type fittings, with SAE "Dryseal" or equal, tapered pipe threads may also
be used for root connections. Gland seal piping for commercial marine pumps may be furnished in accordance
with the manufacturer's normal standards for such pumps.
3.6.8.3 Tapered threads shall not be used in equipment required to be shockproof, except as permitted in
MIL-STD-438 and MIL-STD-777. Pipe connections shall be of the flanged, union, brazed or welded type as
applicable. Should this not be feasible, a straight thread fitting of a type approved by the bureau or agency
concerned may be used.
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