Pump Characteristics and Applications 3rd Edition By Michael Volk

Pages 502
Views 678
Size 29.6 MiB
Downloads 134
Pump Characteristics and Applications 3rd Edition By Michael Volk

Tags:

Contents

Preface to the Third Edition. ……………………………………………………………………..xv
Preface to the Second Edition. …………………………………………………………………xvii
Preface to the First Edition. ………………………………………………………………………xix
Acknowledgments. ………………………………………………………………………………..xxiii
Author. ……………………………………………………………………………………………………xxv
1. Introduction to Pumps. ………………………………………………………………………..1
I. What Is a Pump?. ………………………………………………………………………..1
II. Why Increase a Liquid’s Pressure?. ……………………………………………..2
III. Pressure and Head. ……………………………………………………………………..3
IV. Classification of Pumps. ………………………………………………………………4
A. Principle of Energy Addition. ………………………………………………4
1. Kinetic. ……………………………………………………………………….4
2. Positive Displacement. ………………………………………………..4
B. How Energy Addition Is Accomplished. ……………………………..6
C. Geometry Used. …………………………………………………………………..6
V. How Centrifugal Pumps Work. …………………………………………………..6
VI. PD Pumps. …………………………………………………………………………………12
A. General. ……………………………………………………………………………..12
B. When to Choose a PD Pump. …………………………………………….12
C. Major Types of PD Pumps. ………………………………………………..15
1. Sliding Vane Pump. …………………………………………………..19
2. Sinusoidal Rotor Pump. …………………………………………….20
3. Flexible Impeller Pump. ……………………………………………20
4. Flexible Tube (Peristaltic) Pump. ……………………………….21
5. Progressing Cavity Pump. ………………………………………..22
6. External Gear Pump. …………………………………………………23
7. Internal Gear Pump………………………………………………….25
8. Rotary Lobe Pump. …………………………………………………..26
9. Circumferential Piston, Bi-Wing Lobe Pumps. ……………27
10. Multiple-Screw Pump. ………………………………………………28
11. Piston Pump. …………………………………………………………….29
12. Plunger Pump. ………………………………………………………….31
13. Diaphragm Pump. …………………………………………………….32
14. Miniature PD Pumps. ……………………………………………….35
2. Hydraulics, Selection, and Curves. ……………………………………………………39
I. Overview. ………………………………………………………………………………….39
II. Pump Capacity. …………………………………………………………………………41
III. Total Head. ………………………………………………………………………………..42
© 2008 Taylor & Francis Group, LLC
A. Static Head………………………………………………………………………..43
B. Friction Head. ……………………………………………………………………46
C. Pressure Head. …………………………………………………………………..57
D. Velocity Head. ……………………………………………………………………58
IV. Performance Curve. …………………………………………………………………..60
V. Horsepower and Efficiency. ………………………………………………………68
A. Hydraulic Losses. ………………………………………………………………70
B. Volumetric Losses. …………………………………………………………….70
C. Mechanical Losses. ……………………………………………………………70
D. Disk Friction Losses. ………………………………………………………….70
VI. NPSH and Cavitation. ……………………………………………………………….76
A. Cavitation and NPSH Defined. ………………………………………….76
1. NPSHa. ………………………………………………………………………81
2. NPSHr. ………………………………………………………………………84
B. Calculating NPSHa: Examples. …………………………………………..85
C. Remedies for Cavitation. ……………………………………………………86
D. More NPSHa Examples. ……………………………………………………..89
E. Safe Margin NPSHa versus NPSHr. ……………………………………92
F. NPSH for Reciprocating Pumps. ……………………………………….96
VII. Specific Speed and Suction Specific Speed………………………………..97
VIII. Affinity Laws. ………………………………………………………………………….103
IX. System Head Curves. ……………………………………………………………….107
X. Parallel Operation. …………………………………………………………………..116
XI. Series Operation. ……………………………………………………………………..122
XII. Oversizing Pumps. ………………………………………………………………….126
XIII. Pump Speed Selection. …………………………………………………………….128
A. Suction Specific Speed. …………………………………………………….129
B. Shape of Pump Performance Curves……………………………….129
C. Maximum Attainable Efficiency. ……………………………………..129
D. Speeds Offered by Manufacturers. …………………………………..133
E. Prior Experience. ……………………………………………………………..133
3. Special Hydraulic Considerations. …………………………………………………..135
I. Overview. ………………………………………………………………………………..135
II. Viscosity. …………………………………………………………………………………135
III. Software to Size Pumps and Systems. ……………………………………..150
A. General. ……………………………………………………………………………150
B. Value of Piping Design Software. …………………………………….151
C. Evaluating Fluid Flow Software. ……………………………………..152
D. Building the System Model. ……………………………………………..153
1. Copy Command. ……………………………………………………..154
2. Customize Symbols. ………………………………………………..154
3. CAD Drawing Features. ………………………………………….154
4. Naming Items. …………………………………………………………154
5. Displaying Results. ………………………………………………….155
© 2008 Taylor & Francis Group, LLC
6. The Look of the Piping Schematic. …………………………..155
E. Calculating the System Operation. …………………………………..155
1. Sizing Pipe Lines. ……………………………………………………156
2. Calculating Speed. …………………………………………………..156
3. Showing Problem Areas. …………………………………………156
4. Equipment Selection……………………………………………….156
5. Alternate System Operational Modes. ……………………..157
F. Communicating the Results. ……………………………………………157
1. Viewing Results within the Program. ……………………..157
2. Incorporating User-Defined Limits. ………………………..157
3. Selecting the Results to Display. ……………………………..157
4. Plotting the Piping Schematic. …………………………………158
5. Exporting the Results. ……………………………………………..158
6. Sharing Results with Others. …………………………………..158
7. Sharing Results Using a Viewer Program. ……………….158
G. Conclusion. ………………………………………………………………………158
H. List of Software Vendors. …………………………………………………159
IV. Piping Layout. ………………………………………………………………………….159
V. Sump Design. …………………………………………………………………………..165
VI. Field Testing. ……………………………………………………………………………166
A. General. ……………………………………………………………………………166
B. Measuring Flow. ………………………………………………………………167
1. Magnetic Flowmeter. ………………………………………………168
2. Mass Flowmeter. ……………………………………………………..168
3. Nozzle. …………………………………………………………………….168
4. Orifice Plate. ……………………………………………………………168
5. Paddle Wheel. ………………………………………………………….169
6. Pitot Tube. ……………………………………………………………….169
7. Segmental Wedge. …………………………………………………..169
8. Turbine Meter. …………………………………………………………169
9. Ultrasonic Flowmeter. ……………………………………………..169
10. Venturi. ……………………………………………………………………170
11. Volumetric Measurement. ……………………………………….170
12. Vortex Flowmeter. …………………………………………………..170
C. Measuring TH. …………………………………………………………………171
D. Measuring Power. ……………………………………………………………173
E. Measuring NPSH. ……………………………………………………………173
4. Centrifugal Pump Types and Applications. ……………………………………175
I. Overview. ………………………………………………………………………………..175
II. Impellers. …………………………………………………………………………………176
A. Open versus Closed Impellers. ………………………………………..176
B. Single versus Double Suction. ………………………………………….182
C. Suction Specific Speed. …………………………………………………….183
D. Axial Thrust and Thrust Balancing. ………………………………..185
E. Filing Impeller Vane Tips. ………………………………………………..187
F. Solids Handling Impellers. ………………………………………………189
III. End Suction Pumps. …………………………………………………………………190
A. Close-Coupled Pumps. …………………………………………………….190
B. Frame-Mounted Pumps. ………………………………………………….193
IV. Inline Pumps. ………………………………………………………………………….195
V. Self-Priming Centrifugal Pumps. …………………………………………….197
VI. Split-Case Double Suction Pumps. …………………………………………..199
VII. Multistage Pumps. …………………………………………………………………..203
A. General. ……………………………………………………………………………203
B. Axially Split-Case Pumps. ……………………………………………….203
C. Radially Split-Case Pumps. ……………………………………………..207
VIII. Vertical Column Pumps. ………………………………………………………….208
IX. Submersible Pumps. ………………………………………………………………..213
X. Slurry Pumps. ………………………………………………………………………….215
XI. Vertical Turbine Pumps. …………………………………………………………..218
XII. Axial Flow Pumps. ………………………………………………………………….226
XIII. Regenerative Turbine Pumps. ………………………………………………….227
XIV. Pump Specifications and Standards. ………………………………………..228
A. General. ……………………………………………………………………………228
1. Liquid Properties. ……………………………………………………229
2. Hydraulic Conditions. ……………………………………………..229
3. Installation Details. …………………………………………………229
B. ANSI. ……………………………………………………………………………….230
C. API. ………………………………………………………………………………….232
D. ISO. ………………………………………………………………………………….233
XV. Couplings. ……………………………………………………………………………….234
XVI. Electric Motors. ………………………………………………………………………..240
A. Glossary of Frequently Occurring Motor Terms. ……………..240
1. Amps. ……………………………………………………………………..240
2. Code Letter. …………………………………………………………….241
3. Design Letter. ………………………………………………………….241
4. Efficiency. ………………………………………………………………..242
5. Frame Size. ………………………………………………………………242
6. Frequency……………………………………………………………….242
7. Full-Load Speed. ……………………………………………………..242
8. High Inertial Load. ………………………………………………….242
9. Insulation Class. ………………………………………………………242
10. Load Types. ……………………………………………………………..242
11. Phase. ………………………………………………………………………243
12. Poles. ……………………………………………………………………….243
13. Power Factor. …………………………………………………………..243
14. Service Factor. …………………………………………………………244
15. Slip. …………………………………………………………………………244
16. Synchronous Speed. ………………………………………………..244
17. Temperature. …………………………………………………………..244
18. Time Rating. ……………………………………………………………244
19. Voltage. ……………………………………………………………………245
B. Motor Enclosures…………………………………………………………….245
1. Open Drip-Proof. …………………………………………………….245
2. Totally Enclosed Fan Cooled. …………………………………..245
3. Totally Enclosed Air Over. ………………………………………246
4. Totally Enclosed Nonventilated. ……………………………..246
5. Hazardous Location. ……………………………………………….246
C. Service Factor. ………………………………………………………………….246
D. Insulation Classes. …………………………………………………………..247
E. Motor Frame Size. ……………………………………………………………247
1. Historical Perspective. …………………………………………….247
2. Rerating and Temperature. ……………………………………..250
3. Motor Frame Dimensions. ……………………………………….251
4. Fractional Horsepower Motors. ……………………………….251
5. Integral Horsepower Motors. …………………………………..251
6. Frame Designation Variations. ………………………………..251
F. Single-Phase Motors. ……………………………………………………….257
G. Motors Operating on Variable Frequency Drives…………….261
H. NEMA Locked Rotor Code. ……………………………………………..262
I. Amps, Watts, Power Factor, and Efficiency. ……………………..263
1. Introduction. ……………………………………………………………263
2. Power Factor. …………………………………………………………..263
3. Efficiency. ………………………………………………………………..264
4. Amperes. …………………………………………………………………265
5. Summary. ……………………………………………………………….265
5. Sealing Systems and Sealless Pumps. ……………………………………………..267
I. Overview. ………………………………………………………………………………..267
II. O-Rings. …………………………………………………………………………………..267
A. What Is an O-Ring?. …………………………………………………………268
B. Basic Principle of the O-Ring Seal. …………………………………..268
C. The Function of the O-Ring. …………………………………………….268
D. Static and Dynamic O-Ring Sealing Applications. …………..270
E. Other Common O-Ring Seal Configurations. …………………..270
F. Limitations of O-Ring Use. ………………………………………………271
III. Stuffing Box and Packing Assembly. ……………………………………….272
A. Stuffing Box. …………………………………………………………………….273
B. Stuffing Box Bushing. ………………………………………………………273
C. Packing Rings. …………………………………………………………………273
D. Packing Gland. …………………………………………………………………274
E. Lantern Ring. …………………………………………………………………..275
IV. Mechanical Seals. …………………………………………………………………….276
A. Mechanical Seal Advantages. …………………………………………..276
1. Lower Mechanical Losses. ………………………………………276
2. Less Sleeve Wear. …………………………………………………….276
3. Zero or Minimal Leakage. ……………………………………….276
4. Reduced Maintenance. …………………………………………….276
5. Seal Higher Pressures. …………………………………………….276
B. How Mechanical Seals Work. …………………………………………..277
C. Types of Mechanical Seals. ………………………………………………280
1. Single, Inside Seals. …………………………………………………280
2. Single, Outside Seals. ………………………………………………282
3. Single, Balanced Seals. …………………………………………….283
4. Dual Seals. ………………………………………………………………283
5. Gas Lubricated Noncontacting Seals. ………………………286
6. Seal Piping Plans. ……………………………………………………288
V. Sealless Pumps. ……………………………………………………………………….292
A. General. ……………………………………………………………………………292
B. Magnetic Drive Pumps. ……………………………………………………293
1. Bearings in the Pumped Liquid. ……………………………..295
2. Dry Running. ………………………………………………………….296
3. Inefficiency……………………………………………………………..296
4. Temperature. …………………………………………………………..296
5. Viscosity. …………………………………………………………………297
C. Canned Motor Pumps. …………………………………………………….297
1. Fewer Bearings. ……………………………………………………….299
2. More Compact. ………………………………………………………..299
3. Double Containment. ………………………………………………299
4. Lower First Cost. ……………………………………………………..299
6. Energy Conservation and Life-Cycle Costs. ……………………………………301
I. Overview. ………………………………………………………………………………..301
II. Choosing the Most Efficient Pump. ………………………………………….302
III. Operating with Minimal Energy. …………………………………………….307
IV. Variable-Speed Pumping Systems. …………………………………………..308
V. Pump Life-Cycle Costs. ……………………………………………………………325
A. Improving Pump System Performance: An Overlooked Opportunity?. ………………………………………………………………….326
B. What Is Life-Cycle Cost?. …………………………………………………327
C. Why Should Organizations Care about Life-Cycle Cost?. …..327
D. Getting Started. ……………………………………………………………….328
E. Life-Cycle Cost Analysis. …………………………………………………328
1. Cic—Initial Investment Costs. ………………………………….330
2. Cin—Installation and Commissioning (Start-Up) Costs. ………………………………………………………………………330
3. Ce—Energy Costs……………………………………………………331
4. Co—Operation Costs. ………………………………………………332
5. Cm—Maintenance and Repair Costs. ……………………….332
6. Cs—Downtime and Loss of Production Costs. ………..334
7. Cenv—Environmental Costs, Including Disposal of Parts and Contamination from Pumped Liquid. …334
8. Cd—Decommissioning/Disposal Costs, Including Restoration of the Local Environment. ……..334
F. Total Life-Cycle Costs. ……………………………………………………..335
G. Pumping System Design. …………………………………………………335
H. Methods for Analyzing Existing Pumping Systems. ………..339
I. Example: Pumping System with a Problem Control Valve. …341
J. For More Information. ……………………………………………………..344
1. About the Hydraulic Institute. …………………………………346
2. About Europump. ……………………………………………………346
3. About the U.S. Department of Energy’s Office of Industrial Technologies. ………………………………………….346
7. Special Pump-Related Topics. …………………………………………………………347
I. Overview. ………………………………………………………………………………..347
II. Variable-Speed Systems. ………………………………………………………….348
III. Sealless Pumps. ……………………………………………………………………….348
IV. Corrosion. ………………………………………………………………………………..349
A. Galvanic or Two-Metal Corrosion. …………………………………..351
B. Uniform or General Corrosion. ………………………………………..351
C. Pitting Corrosion. …………………………………………………………….352
D. Intergranular Corrosion. ………………………………………………….353
E. Erosion Corrosion. ……………………………………………………………353
F. Stress Corrosion. ………………………………………………………………354
G. Crevice Corrosion. ……………………………………………………………354
H. Graphitization or Dezincification Corrosion. ……………………354
V. Nonmetallic Pumps. ………………………………………………………………..355
VI. Materials Used for O-Rings in Pumps. …………………………………….357
A. General. ……………………………………………………………………………357
1. Polymer. ………………………………………………………………….357
2. Rubber. ……………………………………………………………………357
3. Elastomer. ……………………………………………………………….357
4. Compound. ……………………………………………………………..358
B. Eight Basic O-Ring Elastomers. ………………………………………..358
1. Nitrile (NBR, Buna N). …………………………………………….358
2. Neoprene. ………………………………………………………………..359
3. Ethylene Propylene (EP, EPR, and EPDM). ………………359
4. Fluorocarbon (FKM, Viton, and Kalrez). ………………….359
5. Butyl. ……………………………………………………………………….360
6. Polyacrylate. …………………………………………………………….360
7. Silicone. …………………………………………………………………..360
8. Fluorosilicone. …………………………………………………………362
VII. High-Speed Pumps. …………………………………………………………………363
VIII. Bearings and Bearing Lubrication. …………………………………………..365
IX. Precision Alignment Techniques. …………………………………………….366
X. Software to Size Pumps and Systems. ……………………………………..367
8. Installation, Operation, Maintenance, and Repair. …………………………369
I. Overview. ………………………………………………………………………………..369
II. Installation, Alignment, and Startup. ………………………………………369
A. General. ……………………………………………………………………………369
B. Installation Checklist. ………………………………………………………370
1. Tag and Lock Out. …………………………………………………..370
2. Check Impeller Setting. …………………………………………..370
3. Install Packing or Seal. …………………………………………….371
4. Mount Bedplate, Pump, and Motor. …………………………371
5. Check Rough Alignment. ………………………………………..371
6. Place Grout in Bedplate. …………………………………………..373
7. Check Alignment. ……………………………………………………373
8. Flush System Piping. ……………………………………………….373
9. Connect Piping to Pump. ………………………………………..374
10. Check Alignment. ……………………………………………………375
11. Turn Pump by Hand. ………………………………………………375
12. Wire and Jog Motor. ………………………………………………..375
13. Connect Coupling. …………………………………………………..376
14. Check Shaft Runout. ………………………………………………..376
15. Check Valve and Vent Positions. ……………………………..376
16. Check Lubrication/Cooling Systems. ………………………376
17. Prime Pump if Necessary. ……………………………………….376
18. Check Alignment. ……………………………………………………377
19. Check System Components Downstream. ……………….377
20. Start and Run Pump. ……………………………………………….377
21. Stop Pump and Check Alignment. ………………………….378
22. Drill and Dowel Pump to Base. ……………………………….378
23. Run Benchmark Tests. ……………………………………………..378
III. Operation………………………………………………………………………………..378
A. General. ……………………………………………………………………………378
B. Minimum Flow. ……………………………………………………………….379
1. Temperature Rise. ……………………………………………………379
2. Radial Bearing Loads. ……………………………………………..380
3. Axial Thrust. …………………………………………………………..380
4. Prerotation. ……………………………………………………………..380
5. Recirculation. ………………………………………………………….381
6. Settling of Solids. …………………………………………………….382
7. Noise and Vibration. ……………………………………………….382
8. Power Savings, Motor Load. ……………………………………383
C. Preferred Operating Range. ……………………………………………..383
D. Ten Ways to Prevent Low Flow Damage in Pumps. …………384
1. Continuous Bypass. …………………………………………………385
2. Multicomponent Control Valve System. …………………..385
3. Variable Frequency Drive. ……………………………………….386
4. Automatic Recirculation Control Valve. …………………..387
5. Relief Valve. …………………………………………………………….388
6. Pressure Sensor. ………………………………………………………388
7. Ammeter. ………………………………………………………………..389
8. Power Monitor. ………………………………………………………..389
9. Vibration Sensor. ……………………………………………………..389
10. Temperature Sensor. ……………………………………………….390
IV. Maintenance. …………………………………………………………………………..390
A. Regular Maintenance………………………………………………………390
1. Lubrication. ……………………………………………………………..390
2. Packing. …………………………………………………………………..391
3. Seals. ……………………………………………………………………….392
B. Preventive Maintenance. ………………………………………………….392
1. Regular Lubrication. ………………………………………………..392
2. Rechecking Alignment. …………………………………………..392
3. Rebalance Rotating Element. …………………………………..392
4. Monitoring Benchmarks. …………………………………………393
C. Benchmarks. …………………………………………………………………….393
1. Hydraulic Performance. …………………………………………..393
2. Temperature. …………………………………………………………..393
3. Vibration…………………………………………………………………394
V. Troubleshooting. ……………………………………………………………………..399
VI. Repair. ……………………………………………………………………………………..400
A. General. ……………………………………………………………………………400
B. Repair Tips. ……………………………………………………………………..401
1. Document the Disassembly. ……………………………………401
2. Analyze Disassembled Pump. …………………………………402
3. Bearing Replacement………………………………………………402
4. Wear Ring Replacement………………………………………….403
5. Guidelines for Fits and Clearances. …………………………404
6. Always Replace Consumables. ………………………………..404
7. Balance Impellers and Couplings. …………………………..405
8. Check Runout of Assembled Pump. ………………………..405
9. Tag Lubrication Status…………………………………………….405
10. Cover Openings Prior to Shipment. …………………………405
9. Case Studies. …………………………………………………………………………………….407
I. Introduction. ……………………………………………………………………………407
II. Case Studies. ……………………………………………………………………………407
A. The Case of the Oversized Pump. ……………………………………407
1. Background. ……………………………………………………………407
2. Analysis of the Problem. ………………………………………….408
3. Solutions and Lessons Learned. ………………………………409
B. The Case of the Unreliable Refrigerant Pump. …………………412
1. Background. ……………………………………………………………412
2. Analysis of the Problem. ………………………………………….413
3. Solutions and Lessons Learned. ………………………………417
C. The Case of the Vibrating Vertical Turbine Pump. …………..418
1. Background. ……………………………………………………………418
2. Analysis of the Problem. ………………………………………….419
3. Solutions and Lessons Learned. ………………………………420
D. The Case of Too Many Pumps. …………………………………………421
1. Background. ……………………………………………………………421
2. Analysis of the Problem. ………………………………………….422
3. Solutions and Lessons Learned. ………………………………426
E. The Case of Too Few Pumps. ……………………………………………427
1. Background. ……………………………………………………………427
2. Analysis of the Problem. ………………………………………….431
3. Solutions and Lessons Learned. ………………………………431
F. The Case of the Underperforming Pump. ………………………..433
1. Background. ……………………………………………………………433
2. Analysis of the Problem. ………………………………………….435
3. Solutions and Lessons Learned. ………………………………435
G. The Case of the Problematic Variable Speed Pump. …………437
1. Background. ……………………………………………………………437
2. Analysis of the Problem. ………………………………………….438
3. Solutions and Lessons Learned. ………………………………440
H. The Case of the Shoe-Horned Wastewater Pumps. …………..440
1. Background. ……………………………………………………………440
2. Analysis of the Problem. ………………………………………….442
3. Solutions and Lessons Learned. ………………………………444
I. The Case of the High Suction Specific Speed Pump. ………..445
1. Background. ……………………………………………………………445
2. Analysis of the Problem. ………………………………………….445
3. Solutions and Lessons Learned. ………………………………446
Appendix A: Major Suppliers of Pumps in the United States by Product Type. ………………………………………………………………………………………….449
Appendix B: Conversion Formulae. ……………………………………………………….461
References. ……………………………………………………………………………………………..473

Preface to the Third Edition

This third edition of Pump Characteristics and Applications includes two sig-nificant improvements. First, more than 150 images are presented in color for the first time. Based on feedback from participants in short courses in pumps that have used this book as the text, these color images should greatly improve the ability of readers from all backgrounds to understand the details in many cutaway and cross sectional images of pumps, seals, and other components. Similarly, color-coding permits a clear distinction between the many types of pump performance curves that are presented throughout the book, such as head–capacity, horsepower, efficiency, NPSH, and system head curves. Also included are new images of the latest generation of pumps and other components.
The second focus of this edition is a new chapter on pump case stud-ies. Students in Volk pump training classes indicate that case studies are an important learning tool for people who work with pumps. The new Chapter 9 describes in some detail a series of typical pump field problems and their solutions. Each case study includes background on the pump-related problem, an analysis of the problem, and the resulting solutions and lessons learned.
In addition to the above, the entire book was updated to reflect the latest thinking on pumps. A number of helpful new sections were added, such as the ten steps to determine total head that are summarized in Chapter 2 and the mechanical seal piping plans that are discussed and illustrated in Chapter 5.
The first two editions of the book included a demo CD of the PIPE-FLO Professional piping design and analysis software. With this third edition we have switched to a downloadable demo of the software. PIPE-FLO and other piping design and analysis software programs are discussed in some depth in Chapter 3. Use of a software tool to design or analyze a piping system should be considered if the system is complex (e.g., has multiple branches or loops, includes multiple pumps or a single pump at multiple speeds, or uses a fluid with properties much different from water). Using a software tool to size pipes and determine pump total head allows the piping and pumps to be matched more accurately to the expected demands of the system, and helps to keep the pump from being oversized, thus saving energy and reduc-ing pump maintenance costs. It also gives the system designer or operator a much better understanding of how the pump responds to changes in levels, flows, pressures, and valve positions. For more information on PIPE-FLO and to download a demo of this software, go to the following link: http://www.volkassociates.com/pipeflo.html.
In closing, I would like to invite readers who are interested in attending a more in-depth training course on pumps, either for continuing education units or simply to enhance their understanding of pumps and systems, to go the link below for information on short courses in pumps for engineers and technicians that I periodically offer at a variety of venues, including on-site at company offices (http://www.volkassociates.com/seminars.html).

Preface to the Second Edition

Thankfully, the laws of physics have not changed since the first edition of this book was written in 1996. Therefore, virtually everything about pump selection, sizing, system analysis, and other aspects of pump hydraulics remains unchanged from the first edition. There have, however, been a num-ber of innovations in the world of pumps, which are introduced in this sec-ond edition. This edition also expands the material on many components of typical pump installations that were only briefly covered in the first edition, if at all. Some of the most important new or expanded topics covered in this second edition include

Chapter 1—Several new types of positive displacement (PD) pumps are introduced, while the information on other types of PD pumps has been expanded.

Chapter 2—Important new topics in this chapter include NPSH anal-ysis for closed systems, expansion of the discussion on NPSH mar-gin, and system head curve development for existing systems and for parallel pumping systems.

Chapter 3—In the world of software, nine years is an eternity, and so the entire section of this chapter covering software used to design and analyze pump piping systems has been completely rewritten.

Chapter 4—Entire new sections of this chapter have been added to provide in-depth coverage of two very important and relevant top-ics: pump couplings and electric motors. Additionally, several types of centrifugal pumps that were not included in the first edition are covered in this chapter.

Chapter 5—This chapter has an entire new section on O-rings used in pumps, as well as additional information about sealless pumps.

Chapter 6—Two major additions to the book are included in this chapter. The first is an in-depth discussion of variable-frequency drives. Second, this chapter includes a section covering pump life-cycle cost, an innovative approach to the study of the cost of pumping equipment that looks way beyond the capital cost of the pump.

Chapter 7—This chapter has added in-depth discussion of metallic corrosion in pumps, as well as discourse on elastomers commonly used in pumps for sealing components.

Chapter 8—New topics covered in this chapter include ten methods to prevent low flow damage in pumps, and a much more detailed discussion of vibration, including a detailed vibration troubleshoot-ing chart.
Thanks to my colleagues in the pump field who provided input for this second edition or who reviewed particular sections of it. Finally, I wish to thank my daughter Sarah, who typed major portions of the new material for this edition.

Preface to the First Edition

This book is a practical introduction to the characteristics and applications of pumps, with a primary focus on centrifugal pumps. Pumps are among the oldest machines still in use and, after electric motors, are probably the most widely used machines today in commercial and industrial activities. Despite the broad use of pumps, this subject is covered only briefly in many engineering curricula. Furthermore, companies that use pumps are often unable to provide their engineers, operators, mechanics, and supervisors the kind of training in pump application, selection, and operation that this vital equipment merits.
The purpose of this book is to give engineers and technicians a general understanding of pumps and to provide the tools to allow them to prop-erly select, size, operate, and maintain pumps. There are numerous books on the market about pumps, but most of them are very technical, and are mainly design oriented, or else are directed to a specific niche market. I have attempted to provide practical information on pumps and systems to readers with all levels of experience, without getting so immersed in design details as to overwhelm the reader.
This book begins with the basics of pump and system hydraulics, working gradually to more complex concepts. The topics are covered in a clear and concise manner and are accompanied by examples along the way. Anyone reading the material, regardless of education and experience with pumps, will be able to achieve a better understanding of pump characteristics and applications.
Although it is not possible to cover pump hydraulics without getting into some mathematics, this book covers the subject without resorting to differ-ential equations and other high level mathematics that most people forgot right after school. For the reader who is interested in a more complex or sophisticated approach to particular topics or who wants additional infor-mation in a given area, references are made to other sources that provide a more analytical approach.
A theme that is repeated throughout this book is that all aspects of pumps—from system design, to pump selection, to piping design, to instal-lation, to operation—are interrelated. Lack of attention to the sizing of a pump or improper design of the piping system can cause future problems with pump maintenance and operation. Even the most precisely sized pump will not perform properly if its installation and maintenance are not per-formed carefully. A better understanding of how these issues are related will help to solve problems or to prevent them from occurring in the first place.
In addition to a thorough treatment of the fundamentals, this book also provides information on the current state of the art of various technolo-gies in the pump field. Variable speed pumping systems, sealless pumps, gas-lubricated noncontacting mechanical seals, and nonmetallic pumps are examples of recent technological trends in the pump industry that are intro-duced in this book. Computer software for system design and pump selec-tion is previewed in Chapter 3. This is another example of a powerful new technology related to pumps that is covered in this book.
Because the book focuses on pump applications and characteristics, rather than on design, it is intended for a broader audience than typical books about pumps. The readership for this book includes the following:

Engineers—This book has broad appeal to mechanical, civil, chemi-cal, industrial, and electrical engineers. Any engineer whose job it is to design or modify systems; select, specify, purchase, or sell pumps; or oversee operation, testing, or maintenance of pumping equip-ment will find this book very helpful.

Engineering supervisors—Because they have broad responsibility for overseeing the design and operation of pumps and pump systems, engineering supervisors will benefit from the integrated systems approach provided in this book.

Plant operators—Employees of plants that utilize pumps are required to oversee the operation of the pumps, and often their maintenance, troubleshooting, and repair. A better understanding of hydraulics and applications will help these people do a better job of operating their pumps most efficiently while reducing maintenance costs and downtime.

Maintenance technicians—Maintenance personnel and their supervi-sors can do a much better job of installing, maintaining, trouble-shooting, and repairing pumps if they have a better understanding of how pumps are applied and operated in a system.

Engineering students—The “real-world” problems that are presented in this book demonstrate to students that a pump is more than a “black box.” Many university engineering departments are expand-ing their technology program to better prepare students for jobs in industry. This book can make an important contribution to a pro-gram in industrial machinery.
The formulae used in this book will generally be stated in U.S. Customary System (USCS) units, the system most widely used by the pump industry in the United States. Appendix B at the end of this book provides simple con-version formulae from USCS to SI (metric) units. The most common terms mentioned in this book will be stated in both units.
I wish to thank my colleagues in the pump field who reviewed various sections of this book or who assisted in obtaining materials and illustrations. I am especially grateful to my friends Jim Johnston, Paul Lahr, and Buster League, who reviewed the entire manuscript and provided me with valuable feedback. Final thanks go to my wife, Jody Lerner, for her word processing and editorial skills as well as for her patience and encouragement.