Impeller Clearances; Methods To Determine Impeller Nose Clearance - Goulds Pumps JC Installation, Operation And Maintenance Instructions

Impeller clearances

WARNING:
Improper impeller adjustment could cause contact between the rotating and stationary
parts, resulting in a spark and heat generation.
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 0.396mm - 0.792mm | 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.
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 12: Impeller clearance

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
2. To decrease impeller clearance, loosen outboard jam nut and drive the shaft assembly by
Model JC Installation, Operation and Maintenance Instructions
The impeller clearance setting procedure must be followed. Improperly setting the
direction. Moving shaft (122) toward suction side casing liner will decrease the clearance
turning the inboard jam nut.
Preventive Maintenance
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