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Contents

10.2.1.7 Pipe fittings 173
10.3 Alignment 174
10.3.1 Shaft couplings 175
10.3.2 Shaft offset and angularity 176
10.3.3 High temperature corrections 177
10.3.4 Typical acceptance values 178
10.3.5 Run out 178
10.3.6 Soft foot 179
10.3.7 Alignment methodology 179
10.3.8 C-flange adapter 179

11 Troubleshooting 181
11.1 Skill and experience 181
11.2 Operational problems 182
11.2.1 Cavitation problem solving 182
11.2.2 Uncurable conditions 184
11.3 Reliability problems 185
11.4 Failure analysis 186
11.4.1 Speed of problem occurrence 187
11.4.1.1 Excessive power consumption 187
11.4.2 Frequency of problem occurrence 187
11.4.2.1 Hydraulic imbalance in a
double suction pump 188
11.4.2.2 Undersized shaft in an
end suction pump 188
11.5 Failure modes 190
11.5.1 Impeller 190
11.5.2 Wear rings 191
11.5.3 Shaft 192
11.5.4 Sleeve 193
11.5.5 Bearings 193
11.5.6 Packing 194
11.5.7 Mechanical seal - general 195
11.5.7.1 Mechanical seal - seal faces 197

12 Pump Maintenance 201
12.1 The strategy 201
12.1.2 Economic considerations 202
12.2 Preparation for pump dismantling 203
12.3 Removing the back pull-out assembly 204
12.4 Inspection checks on cast parts 204
12.5 Casing and wear rings 205

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