7.4 Wearing rings
Casing wearing rings are provided for both hubs of the impeller on some sizes and only on the suction
hub on others. Refer to Sectional assembly parts and interchangeability chart. These rings allow a small
clearance to be maintained between the rotating impeller and the stationary casing wearing rings. For
proper hydraulic performance these clearances should be maintained as indicated below. Ring should be
replaced when clearances have worn to those listed under replacement clearance.
Table shows original clearances and suggested replacement clearances as follows:
Ring Bore Dia., In.
Diametrical Clearance, In.
Original
Replacement
Under 2" Dia.
0.010-0.014
0.020-0.024
2" to 2-1/2" Dia.
0.011-0.015
0.021-0.025
2-1/2" to 3-1/2 Dia.
0.014-0.018
0.024-0.028
3-1/2" to 4-1/2 Dia.
0.016-0.020
0.026-0.030
Over 4-1/2" Dia.
0.018-0.022
0.028-0.032
To check ring clearances or for replacement proceed as follows:
1.
Shut off all piping and disconnect suction piping.
2.
Drain liquid from pump.
3.
Unscrew nuts from studs (356) and remove cover (182) from casing.
If pump has only a suction wearing ring, as indicated from Sectional assembly parts and inter-
changeability chart then check outside diameter of impeller hub and inside diameter of casing
wearing ring in casing cover.
If pump is designed with two wearing rings:
4.
Remove impeller nut (304) and washer (199).
5.
By use of a suitable puller similar to that shown in Fig. 4 pull impeller from shaft. (Puller must
push against shaft as shown. Do not use a type that pulls from casing). All impellers are provided
with two tapped holes to facilitate use of a puller.
6.
Check diameters of both hubs and rings. If clearances are excessive, the rings should be re-
placed. See recommended clearance chart above.
7.
Remove rings from cover and casing.
8.
Clean bore in which rings seat and press new rings evenly into place.
9.
Replace impeller, washer, nut and casing cover all directed in
7.3 Replacing shaft sleeve on page
7.5
Replacing impeller
1.
Shut off all piping and disconnect suction piping.
2.
Drain liquid from pump.
3.
Unscrew nuts on studs (356) and remove suction cover (182) from casing.
4.
Remove impeller nut (304) and impeller washer (199) from shaft.
5.
By use of a suitable puller similar to that shown in Fig. 4 pull impeller from shaft. (Puller must push
against shaft as shown. Do not use a type that pulls from casing). All impellers are provided with
two tapped holes to facilitate use of a puller.
6.
Check diameters of impeller hubs and wearing rings to determine if new rings are needed. Replace
rings in suction cover or casing if necessary. Refer to recommended clearance chart at left.
7.
Slide new impeller on shaft as far as possible.
7.4 Wearing rings
26
3655 Installation, Operation and Maintenance Instructions
