AWWA 20677-2009 Pump Selection and Troubleshooting Field Guide.pdf

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1、The Authoritative Resource on Safe WaterAdvocacyCommunicationsConferencesEducation and TrainingScience and TechnologySectionsPump Selection and Troubleshooting Field Guide#MBOL1BHFPump Selection and Troubleshooting Field GuideRichard P. Beverly, PEPump Selection and Troubleshooting Field Guide: Copy

2、right 2009 American Water Works AssociationAWWA Publications Manager: Gay Porter De NileonSenior Technical Editor: Melissa Valentine Production Editor: Cheryl ArmstrongProduced by: Hop-To-It Design WorksAll rights reserved. No part of this publication may be reproduced or transmitted in any form or

3、by any means, electronic or mechanical, including photocopy, recording, or any information or retrieval system, except in the form of brief excerpts or quotations for review purposes, without the written permission of the publisher.DisclaimerThe authors, contributors, editors, and publisher do not a

4、ssume responsibility for the validity of the content or any consequences of their use. In no event will AWWA be liable for direct, indirect, special, incidental, or consequential damages arising out of the use of information presented in this book. In particular, AWWA will not be responsible for any

5、 costs, including, but not limited to, those incurred as a result of lost revenue. In no event shall AWWAs liability exceed the amount paid for the purchase of this book.6666 West Quincy AvenueDenver, CO 80235-3098303.794.7711Library of Congress Cataloging-in-Publication DataBeverly, Richard P.Pump

6、selection and troubleshooting field guide / by Richard P. Beverly.p. cm.Includes bibliographical references and index.ISBN 978-1-58321-727-4 (alk. paper)1. Pumping machinery. I. American Water Works Association. II. Title.TJ900.B485 2009628.144-dc222009016035iiiTable of ContentsList of Figures vAbbr

7、eviations/Definitions viiAcknowledgments ixAbout the Author xiIntroduction 1Pump HorsepowerChapter 1. 3Introduction 3Performance 3Static Head 4Friction Loss 4Horsepower Definitions and Calculations 7Example Problems 10Summary 12Pump TypesChapter 2. 13Introduction 13Centrifugal Pump Types 16Centrifug

8、al Pump Selection 22Vertical Line Shaft Turbine Pumps 27Submersible Pumps 33Estimating Performance 38Flow VariationsChapter 3. 41Introduction 41Throttling 42Variable-Speed-Drive Systems 46Pump Capacity Options 53Summary 55Pump TroubleshootingChapter 4. 57Introduction 57Close Coupled Centrifugal Pump

9、s 57Frame-Mounted Centrifugal Pumps 61Vertical In-Line Centrifugal Pumps 63Vertical Line Shaft Turbine Pumps 63Wet Well Design 66Submersible Pumps 66Maintenance 68Recommendations 68ivChemical PumpsChapter 5. 71Introduction 71Pump Types 71Accessories 79Pump Rate Calculations 86Installation 89Dry Feed

10、ers 91Process Mixing 94Chemical Monitoring 100Process Problems and Solutions 101Comments 103Recommended Maintenance 104Summary 105Operation and Maintenance ManualChapter 6. 107On-Site Records 107Accessories 108Written Procedure 108Appendix: Chemical Resistance Chart 109Index 117vList of FiguresFigur

11、e 1-1 Typical centrifugal pump systems 5Figure 1-2 Pumping height miscellaneous pumps 6Figure 1-3 Typical centrifugal pump family of curves 9Figure 2-1 Net positive suction head (NPSH) 14Figure 2-2 NPSH requirements 15Figure 2-3a Typical close coupled centrifugal pump 17Figure 2-3b Vertical centrifu

12、gal pump 18Figure 2-3c Frame-mounted centrifugal pump 18Figure 2-4 Typical centrifugal pump family of curves 19Figure 2-5 Impeller curves 20Figure 2-6 Hydraulic efficiency curves 21Figure 2-7 Brake horsepower curves 22Figure 2-8 Net positive suction head curve 23Figure 2-9 Proposed design efficiency

13、 24Figure 2-10 Pump selection, operation, and variable-frequency drives 26Figure 2-11 Centrifugal pump curve shape 27Figure 2-12 Typical vertical line shaft turbine pump 29Figure 2-13 Unstable operation 31Figure 2-14 Typical vertical turbine pump curve 32Figure 2-15 Typical submersible pump cross se

14、ction 33Figure 2-16 Deep well submersible pump 34Figure 2-17 Typical submersible pump curve 35Figure 2-18 Typical submersible pump installation 36Figure 2-19 Duplex unit with valve box 36Figure 2-20 Pressure gauge installation 40Figure 3-1 Effects of throttling 43Figure 3-2 Effects of throttling on

15、motor size 45Figure 3-3 Variable-frequency drive 46Figure 3-4 Variable-speed pump calculations 47Figure 3-5 1,750-rpm pump curve 49Figure 3-6 1,150-rpm pump curve 49Figure 3-7 Comparison of 1,750- versus 1,150-rpm speed 51Figure 3-8 Large potable water system operation 52Figure 4-1 Typical close cou

16、pled centrifugal pump 58Figure 4-2 Frame-mounted centrifugal pump 62Figure 4-3 Vertical centrifugal pump 64Figure 4-4 Typical vertical line shaft turbine pump 65Figure 5-1 New type of chemical fee pump 72Figure 5-2 Diaphragm pumps 72Figure 5-3 Diaphragm pump assembly 73Figure 5-4 Diaphragm pump head

17、 assembly 74Figure 5-5 Diaphragm pump suction cycle 75Figure 5-6 Diaphragm pump discharge cycle 76viFigure 5-7 Diaphragm pump viscous solutions 77Figure 5-8 Polymer dilution/mixing system 77Figure 5-9 Peristaltic pump system 78Figure 5-10 Progressive cavity pumps 79Figure 5-11 Polymer day tanks/mix

18、tanks 80Figure 5-12 Chemical system assemblies 82Figure 5-13 Automatic flushing system 84Figure 5-14 Manual flushing 84Figure 5-15 Injector assembly 85Figure 5-16 Small pump and mix tank assemblies 90Figure 5-17 Pump installation 91Figure 5-18 Dry feeders 92Figure 5-19 Fluoride saturator 95Figure 5-

19、20 Desired mixing 96Figure 5-21 Direct chemical injection 97Figure 5-22 Direct injection 97Figure 5-23 Injection quill 98Figure 5-24 Mechanical flash mixer 99Figure 5-25 Static mixer 99Figure 5-26 Flow over weir chemical injection 100Figure 5-27 Diaphragm pump spare parts K17 105viiAbbreviations/Def

20、initionsCavitation. Vaporization of water under low pressure conditions (usually on the suction side of a pump), followed by implosions of the air bubbles when pressurized on the discharge side.Discharge pressure (H). The discharge pressure of a pump usually expressed in feet of water.Flow (Q). The

21、discharge pressure of a pump usually expressed in gallons per minute (gpm).HorsepowerWater horsepower (frictionless). The power required to lift a weight of water to a specific height, not including friction. It is usually calculated in terms of foot-pounds per minute, or gallons per minute.Brake. T

22、he actual power delivered to the water, taking into account pump efficiency. Sometimes referred to as the braking power required to stop the motor shaft.Actual Motor. Brake horsepower divided by motor efficiency, and then rounded up to the nearest commercially available motor size.NPSH. Net positive

23、 suction head. The total suction pressure on a pump inlet, including atmospheric.NPSHR. The net positive suction head for a particular pump to operate properly at a specified flow rate and discharge pressure.O&M. Operations and maintenance.Trim pump. A pump used to vary the flow by a small amount to

24、 match changing system demand.ixAcknowledgmentsThe author wishes to thank the following people for helping make this book possible:Technical Material: PACO/Grundfos Liquid Metronics, Inc.Peer Review: Dave Davis, Sunrise Water Authority Alan Schacht, Sunrise Water AuthorityGraphics: Tim DouglasWord P

25、rocessing and Organization: Nancy JelinekxiAbout the AuthorMr. Phil Beverly has a B.S. degree in Engineering from the Virginia Polytechnic Institute. He has professional licenses in civil, mechanical, and environmental engineering. He is also a certified Water Rights Examiner and a Level 3 Water Tre

26、atment Plant Operator with the filter endorsement in the State of Oregon. He has served on the AWWA B604 Standards Counsel Subcommittee for Granular Activated Carbon and Filter Media and is currently serving on the regional AWWA Seminars Committee. He was on the Environmental Registry Whos Who, 1992

27、.Mr. Beverly has more than 35 years experience in troubleshooting pumps and filters in both water and wastewater applications. He has helped rehabilitate approximately 200 filter plants and has been retained as a special consultant to resolve problems in numerous filtration and pumping facilities fo

28、r water and wastewater treatment systems across the United States.Mr. Beverlys background includes working for several water/wastewater equipment suppliers and several consulting engineering companies. As part of that experience, he operated a research lab for an equipment supplier, which resulted i

29、n his obtaining three patents on filter underdrain improvements. Mr. Beverlys services are provided by Process Consulting and Troubleshooting, L.L.C., in Elgin, Oregon. To contact the author, call 541-786-0907 or 541-437-2402. The American Water Works Association published Mr. Beverlys book, Filter

30、Troubleshooting and Design Handbook, in 2005. The handbook describes basic gravity filter design, including layering the support gravel, types of media, driving head, underdrain hydraulics, controls, and backwash optimization. Both handbooks are available at www.awwa.org/bookstore. 1IntroductionA wa

31、ter system consists of many components, including a power supply, electrical wiring, switchgear, motor starters, the pumps themselves, a piping network or distribution system to deliver the water, storage reservoirs, and system controls. For these reasons, pumps should be evaluated according to the

32、needs of the system. All the components must be sized and selected properly for the system to operate correctly.The factors used to size a pump include flow (Q-gpm), pressure (H head in feet), and motor horsepower (HP). These factors are of most interest to operation and maintenance (O&M) personnel.

33、 Once a pump has been designed and installed, the flow and pressure are the factors most easily verified by an operator. Other factors, such as pump type, impeller size, bearing selection, etc., are normally the province of the designer or manufacturer.Pumps are usually the most expensive part of a

34、water system to operate. Even so, they are easy to neglect when they are operating properly or seem to be. Pumps can also be very expensive to repair or replace after a failure. Such repairs can be time consuming and take staff away from other important duties. The author is aware of one facility wh

35、ere the water storage in the system was nearly depleted while an essential pump was being replaced. No fire flow capacity was available during that time as well.It is the intent of this handbook to provide quick and easy methods to determine whether a pump is operating properly. For example, by usin

36、g a pumps family of curves (the complete set of curves for a particular pump), it is possible to evaluate a pumps performance using a pressure gauge and flowmeter, and by touch. Information in this handbook describes pump operation and how the factors (flow, discharge pressing, and horsepower) can b

37、e easily used to evaluate performance. O&M personnel do not necessarily need to know how to design a pump, but it would be helpful to be able to read the family of curves and understand their meaning.The handbook is organized into six chapters, as follows:Chapter 1 Pump HorsepowerProcedures for calc

38、ulating horsepower required for a pump are 2 Pump Selection and Troubleshooting Field Guidedescribed. By using the family of curves, a determination can be made whether a pump is operating in the proper range.Chapter 2 Pump TypesReading and understanding pump curves is discussed, and several common

39、pump types are described, along with operational guidelines and methods of evaluating pump performance by touch and by using a pressure gauge and flowmeter.Chapter 3 Variable FlowThe effects of varying the flow in a pump by throttling or changing speed are discussed, along with the benefits of each.

40、Chapter 4 Pump TroubleshootingMethods of identifying typical pump problems are discussed, together with common solutions.Chapter 5 Chemical PumpsFeed systems for common types of chemicals are discussed, along with sizing criteria and O&M recommendations. Typical problems and solutions are also prese

41、nted.Chapter 6 Operation and Maintenance ManualReference information is recommended for on-site records. 3CHAPTER 1Pump HorsepowerIntroductionOnce a pump is operating correctly, it should continue to do so if it is maintained properly and the system conditions remain the same. However, the available

42、 horsepower may limit the operating range of a pump. For example, changes in the demand of the system may re-quire an increase in horsepower, or even a new pump.Calculations should be kept on site to allow a quick review of the sizing of a pump and motor. If there are changes, or if a pump is not op

43、erating properly, the sizing criteria can quickly be reviewed for compliance. Although O&M personnel do not normally have to make those calculations, they have been included in operator certification tests. The most important procedure is the ability to use horsepower information to read a pump curv

44、e. This chapter and Chapter 2 dem-onstrate how this is performed. Information should be available to O&M staff for this purpose.PerformanceThe performance factors of a pump need to be calculated during design and used for evaluation. The factors include the design flow (Q), usually expressed in gall

45、ons per minute, and pressure (or head) in pounds per square inch or feet of water. Q is determined by the pro-cess requirement, and is different for each installation. The pressure or head required for the pump discharge includes the sum of the static head and friction loss caused by piping, valves,

46、 fittings, flow-meters, etc. A general discussion of discharge pressure (pressure boost) is included to determine the horsepower for a pump.It is important to understand that the discharge pressure of a pump alone is usually not an indication of the power/pressure added by the pump. The pressure boo

47、st (pressured added) has to take into account the suction side pressure. For example, if the discharge pres-sure of a pump is 100 psi, and the suction side pressure is 20 psi (flooded suction), the pressure boost by the pump is 80 psi (100 20). 4 Pump Selection and Troubleshooting Field GuideWith a

48、suction lift of 5 psi and a discharge pressure of 100 psi, the pressure boost would be 105 psi (100 + 5).The design (normal) discharge pressure, the normal suction side pressure, and the normal pressure boost should be identified for O&M personnel in the recommended on-site O&M manual. The following

49、 discussion is intended to help O&M personnel understand these terms and how they are calculated.Static HeadThe pumping height, or static head, is illustrated in Figure 1-1. The pumping height is the vertical distance from the original wa-ter surface to the finished water surface, whether the pump has a suction lift or a positive suction head (flooded suction). For a con-servative approach, it is important that the maximum level of the receiving reservoir be used for design, along with the lowest level of the water source