Graham Corporation
21
5.3 Shaft Bearings
The size 30000, 40000, and 50000 pumps use sealed-for-life bearings that are not regreasable.
Size 60000 and larger pumps use regreasable bearings that are pre-packed at the factory. Some
grease may ooze out of the bearing housing during the break-in period. The regreasable bearings
should be lubricated after 3000 hours running time. Lithium based greases are recommended.
For Size 90000 pumps, the bearings are pre-packed at the factory, but prior to system start-up,
additional grease should be added by using the zerk fitting on each bearing cover.
Approximately 1/2 a tube may be required for each bearing as the intention is to fill each empty
cavity in the bearing cover 1/2 full of grease. If during this procedure an escape of grease is
noted around the oil seal on the inner bearing cover, the bearing has received sufficient
lubrication. Over greasing of the bearing is prevented as the grease can escape around the oil
seal as the bearing heats up during operation.
If either bearing cover is removed on the outboard end of the Size 90000 pump, care must be
taken when it is replaced. Also, the bearing cover needs to be tightened evenly. This is critical
since the position of the rotor is determined by the movement of these covers in relation to the
bearing housings on the outboard end. Axial movement of the rotor may cause it to contact the
port plate, damaging the pump at start-up.
The standard bearings are rated for an L10
h
life of 80,000 hours. The temperature of the bearings
should not exceed 140ºF (60ºC). Overheating may be due to excess grease, misalignment of the
shafts, or a bad bearing.
5.4 Gland Packings
The Series 1 pump glands are packed with square braided, graphite coated, cotton fiber packing
material. If the glands leak air into the pump or leak excessive service liquid out of the gland,
tighten the gland follower slightly. (See Section 3.2) If further tightening becomes impossible,
replace the packings.
To replace the packings, remove the gland follower and outboard packing, and then the lantern
ring. The inboard packing can then be removed using an extractor. Lantern rings are not used on
size 30000 pumps.
The new packings should be cut in individual rings. The ends should be located at staggered
positions around the shaft. The lantern ring should be placed in the gland to align with the
gland cooling fluid connection. Replace the outboard packing rings and tighten the gland
follower finger tight. Refer to Section 3.2 for the break-in procedure.
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