Goulds Pumps 3935 Installation, Operation And Maintenance Instructions page 26

Disassembly and reassembly
16
d) Refer to mechanical seal drawing for special seal arrangements.
Table 2: BP20 impeller stack clearance
BP20 Impeller Stack
1st stack
14 stages or less
2nd stack
15th to 20th stages
3rd stack
29th to 42nd stages
4th stack
43rd to 56th stages
5th stack
57th to 70th stages
6th stack
71st to 85th stages
7th stack
85th stage
NOTICE:
1. Steady bearings are located between each stack - every 14 stages.
2. At completion of stacking remove 0.508mm | .020" from front of impellers 21, 29, 35,
43, 49, 57, 63, 71, and 77
Table 3: BP40 impeller stack clearance
BP40 Impeller Stack
1st stack
12 stages or less
2nd stack
13th to 24th stages
3rd stack
25th to 36th stages
4th stack
37th to 39th stages
NOTICE:
1. Steady bearings are located between each stack - every 12 stages.
2. Use only 0.254mm | 0.010" shims for setting front clearance of impellers 25 and 31.
3. At completion of stacking remove one 0.254mm | 0.010" shim from front of (suction
side) impellers 25 and 31.
Table 4: BP70 impeller stack clearance
BP70 Impeller Stack
1st stack
1O stages or less
2nd stack
11th to 20th stages
3rd stack
21st to 30th stages
4th stack
31st to 40th stages
5th stack
41st and 42nd stages
Required Front Clearance
+ 1.016mm ± 0.127mm | + 0.040" ± 0.005"
+ 0.635mm ± 0.127mm | + 0.025" ± 0.005"
+ 0.889mm ± 0.127mm | 0.030" ± 0.005"
+0.889mm ± 0.127mm | +.035" ±.005"
+ 1.016mm ± 0.127mm | + 0.040" ± 0.005"
+1.143mm ± 0.127mm | + 0.045" ± 0.005"
+1.143mm ± 0.127mm | + 0.045" ± 0.005"
Required Front Clearance
+ 1.016mm ± 0.127mm | + 0.040" ± 0.005"
+ 0.635mm ± 0.127mm | + 0.025" ± 0.005"
+ 0.635mm ± 0.127mm | + 0.025" ± 0.005"
+ 0.889mm ± 0.127mm | 0.030" ± 0.005"
Required Front Clearance
+1.016mm ± 0.127mm | +0.040" ± 0.005"
+0.508mm ± 0.127mm |+0.020" ± 0.005"
+0.508mm ± 0.127mm |+0.020" ± 0.005"
+0.635mm ± 0.127mm |+0.025" ± 0.005"
+0.762mm ± 0.127mm |+0.030" ± 0.005"
Model 3935 Installation, Operation and Maintenance Instructions