Goulds Pumps JC - IOM - Manual (Page 25)

POWER END
“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.
IMPELLER CLEARANCES
!
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 clearance 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
1/64" - 1/32" clearance between 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.
METHODS TO DETERMINE
IMPELLER NOSE CLEARANCE
During Installation Or Repair
With a feeler gauge, measure the gap between the nose of
the impeller and the casing liner on the suction side.
During Normal Service
Move impeller toward suction side of casing liner until
parallel surfaces slightly rub. Measure “X” dimension and
add the recommended impeller nose clearance. Adjust
dimension “X” per “Impeller Clearance Adjustment
Procedure.”
Impeller Clearance Adjustment Procedure
1. Turn stud jam nuts at the bearing frame lugs to drive
the shaft assembly in the desired direction. Moving
shaft (122) toward suction side casing liner will
decrease the clearance
2. To decrease impeller clearance, loosen outboard jam
nut and drive the shaft assembly by turning the inboard
jam nut.
3. When desired clearance is reached, tighten outboard
jam nut securely. Check clearance after tightening.
4. To increase impeller clearance, loosen inboard jam nut
and drive the shaft assembly by turning the outboard
jam nut.
$
CAUTION
Jam nuts on both sides of bearing frame lugs must be
secure. Normal impeller thrust will tend to decrease the
impeller clearance. Impeller rubbing will result from
insufficient jam nut tightening.
JC IOM 5/08
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