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|  MIL-P-21343(SHIPS)
3.3.4.5 The stuffing box shall be sealed from the pump discharge or an intermediate stage in a
manner satisfactory to the bureau or agency concerned.
3.3.4.6 The design shall be such as to insure that leakage from the glands cannot reach the bear-
ings or be thrown over bearing housings or driving units. This shall preferably be accomplished by
using glands cored out internally and the shafts provided with flingers. Ample drip pockets, spray
shields and drains shall be provided.
3.3.4.7 Gland and lantern rings shall be split in halves with the halves secured together in a
manner to form solid rings for setting up.
3.3.4.8 All stuffing box glands shall be set up by nuts threaded on gland swing bolts, or on studs
secured in the casings.
3.3.4.9 Sufficient space shall be provided between bearings and stuffing boxes to permit easy
rem oval of packing, and inspection and overhaul of bearings.
3.3.5 Couplings. -
3.3.5.1 A flexible coupling shall be installed between the pump and driving unit.
3.3.5.2 Couplings shall be either bronze, bushed with neoprene or equal, or of an all metal type,
providing the design of the coupling is such as to avoid the generation of noise.
3.3.5.3 All coupling hubs shall be keyed to the shafts and secured by lock nuts. For shafts
one inch in diameter and larger, the hubs shall be fitted on a taper with keys parallel to the tapers.
3.3.6
Bearings.
-
3.3.6.1 A suitable thrust bearing shall be installed at the top of each pump for counteracting any
unbalanced hydraulic or mechanical thrust in either direction. In this connection, consideration shall
be given to the fact that rolling, pitching or list of a ship at sea may introduce thrust loads even
though the unit is in hydraulic balance.
3.3.6.2 Thrust bearings shall be of the combined radial and thrust ball type, They shall preferably
by type 134, class I, single row, angular contact, duplex mounted, ball bearings in accordance with
Specification FF-B-171. Bearings shall be certified "noiseless" in accordance with Specifica-
tion MIL-B-17931 by a Government laboratory.
3.3.6.3 The lower radial bearing shall be of the sleeve type.
3.3.6.4 The use of ball bearings shall be subject to the speed limitations of Specifica-
tions FF-B-171 and FF-B-185, except where prior approval of the bureau or agency concerned has
been granted.
3.3.6.5 Bearings shall be installed in housings separate from and independent of the stuffing boxes
with adequate protection from gland leakage. Suitable means shall be provided to prevent escape of oil
around the shaft. All baffles, wipers and related parts shall be readily renewable.
3.3.7 Lubrication. -
3.3.7.1 The lubrication of ball bearings shall be in accordance with Specification FF-B-171.
3.3.7.2 An alemite grease fitting, or equivalent, shall be installed to lubricate the lower radial
bearing.
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