5.4 Power end
5.4.1 "J " type bearing
The "J" type bearing assembly uses medium-heavy ball bearings. On the small size "J" bearings, double
row ball bearings are used for combined loading. The larger sizes utilize separate radial and thrust ball
bearings. Adjustment of nose clearance can be easily accomplished without bearing disassembly.
5.5 Impeller clearances
WARNING:
•
Improper impeller adjustment could cause contact between the rotating and stationary
parts, resulting in a spark and heat generation.
•
The impeller clearance setting procedure must be followed. Improperly setting the clear-
ance or not following any of the proper procedures can result in sparks, unexpected heat
generation and equipment damage.
To maintain maximum operating efficiency, a uniform 0.396mm - 0.792mm | 1/64" - 1/32" clearance be-
tween the parallel surfaces of suction disc liner (100B) and the nose of the impeller (101) is necessary.
The clearance is adjusted by moving shaft (122) toward or away from suction disc liner (100B). There
are adjusting lugs cast on bearing frame (228) and thrust bearing housing (134A). Studs (356A) threaded
into thrust bearing housing lugs fit through the slots of bearing frame lugs. Jam nuts on studs, located on
both sides of the frame lugs, are used to adjust and fasten the thrust bearing housing relative to the
bearing frame.
1.
Adjusting stud (356A)
2.
Shaft (122)
3.
Bearing housing lug
4.
Bearing frame lug
5.
Inboard jam nut (415)
6.
Outboard jam nut (415)
Figure 13: Impeller clearance
5.4 Power end
Model JC Installation, Operation and Maintenance Instructions
29
