Know and Understand Centrifugal Pumps

Frontmatter......Page 1
Half Title Page......Page 4
Title Page......Page 6
Copyright......Page 7
Table of Contents......Page 8
Prologue......Page 14
About the Authors......Page 16
How do Pumps Work?......Page 18
Absolute Pressure (psia)......Page 21
Pump Head......Page 22
Pressure Measurement......Page 23
Pressures Inside the Pump......Page 24
Introduction 2......Page 29
Definition of NPSHr (required)......Page 30
Definition NPSHa (available)......Page 31
Vapor Pressure......Page 41
The Effects of Vapor Pressure on Pump Performance......Page 42
Cavitation: A Practical Discussion......Page 43
Review for Preventing Cavitation......Page 52
Do Something About Cavitation!!......Page 54
The Laws......Page 56
The Affinity Laws and the Impeller Diameter......Page 59
The Pump’s Minimum Requirements (NPSH)......Page 0
Useful Work from a Pump......Page 61
Flow Determination......Page 63
Factors that Affect the Efficiency......Page 65
Calculating Pump Efficiency......Page 67
Positive Displacement Pumps......Page 68
Centrifugal Pumps......Page 71
Conceptual Difference......Page 72
Centrifugal Volute Pumps......Page 73
Impeller between the Bearings......Page 74
The Typical ANSI Pump......Page 75
API (American Petroleum Institute) Pumps......Page 76
Vertical Turbine Pumps......Page 77
Non-Metallic Pumps......Page 78
Magnetic Drive Pumps......Page 79
Canned Motor Pumps......Page 80
Pump Impellers......Page 81
Turbine Impellers......Page 82
Suction Specific Speed, Nss......Page 83
Open Impellers......Page 87
Totally Enclosed Impeller......Page 88
Wear Bands......Page 89
Specific Speed, Ns......Page 90
Pump Performance Curves......Page 93
Head versus Pressure......Page 94
H-Q......Page 95
Pump Efficiency......Page 97
The Energy (BHp) Curve......Page 98
Family Curves......Page 102
The Elements of the Total Dynamic Head (TDH)......Page 109
Determining the Hp......Page 113
Calculating the Hf and Hv......Page 114
Variable Elevations......Page 127
Dynamic Pressures......Page 130
Short Term Resistance Changes......Page 133
Long Term Resistance Changes......Page 134
Pumps in Parallel and Pumps in Series......Page 137
Pumps in Parallel......Page 139
Three Tips......Page 140
Pumps Running in Series......Page 141
Combined Parallel and Series Pump Operation......Page 142
Introduction 9......Page 145
Operation, Design and Maintenance......Page 150
Signs of Shaft Deflection......Page 153
Interpreting the Evidence......Page 154
The Sweet Zone......Page 157
The Dual Volute Pump......Page 158
Introduction 10......Page 159
Types of Misalignment......Page 161
Alignment Techniques......Page 162
Coupling Alignment......Page 170
Introduction 11......Page 172
Bearing Lubrication......Page 174
Bearing Failure......Page 176
Bearing Maintenance......Page 180
Bearing Seals......Page 184
Vegetable Fibers......Page 188
Reciprocating Action......Page 189
Rotary Action......Page 190
Synthetic Fibers......Page 191
Compression Packing......Page 192
The Lantern Ring......Page 194
Stages in the Life of Packing......Page 195
Pump Packing......Page 197
The Mechanical Seal......Page 201
The Single, Unbalanced, Inside Mounted Mechanical Seal......Page 202
The Single, Balanced, Internal Mechanical Seal......Page 203
Advantages of O-Rings......Page 204
The Balance Effect......Page 205
Advantages of Balance......Page 206
Balance Explained by Math......Page 207
Cartridge Mechanical Seals......Page 209
Double Seals......Page 211
The Tandem Dual Seal......Page 212
The Back-to-Back Double Seal......Page 213
The Face-to-Face Dual Seal......Page 214
The Thermal Convection Tank......Page 215
The Turbo Tank......Page 216
The Pumping Unit......Page 217
Causes of Premature Seal Failure......Page 219
O-Ring (the Elastomer) Failure......Page 221
The Elastomer Sticks to the Shaft......Page 226
The Springs Clog and Jam......Page 227
The Shaft Frets under the Shaft Seal......Page 228
Incorrect Installation Dimension......Page 229
Environmental Controls for Difficult Sealing Applications......Page 230
Difficult Pumping Applications for Mechanical Seals......Page 231
Environmental Controls......Page 232
Proper Pump Repair Alignment Methods......Page 239
Pump Maintenance Files......Page 243
Failure Analysis on Centrifugal Pumps......Page 244
Why is this Pump in the Shop?......Page 245
Erosion......Page 249
Wear Rings......Page 250
Turbulence......Page 252
Throttling......Page 253
Piping Design to Drain Tanks and Sumps......Page 255
The Submergence Laws......Page 260
Index......Page 265
Back Cover......Page 270