Sewage Pumping Handbook

Foreword

Foreword

The use of submersible pumps in sewage and drainage pumping applications has increased greatly in the last decades since they entered the market. The introduction of heavy-duty submersible pumps with motor power ratings exceeding 500 kW has also made them available for central municipal pumping duties. The good service record and high quality standard attained bythese pumps has all but excluded the use of conventional pumps in municipal service. By the same token, the special characteristics of submersible pumps have also required the development of new knowledge on their implementation, such as the design of pumping stations. This work has been advanced by both pump manufacturers and municipal engineers. The intention of this book is to bring the newestinformation on both submersible pumps and pumping stations to the use of all concerned professional people in a concise form. The book is divided into Sections according to the related topics. Basic pump theory is described in Section 1, providing a reference background for the assessment of pump performance. Submersible pump design

and construction is described in Section 2. Pumpperformance is dealt with in Section 3, offering methods for the calculation of pump performance in various installations. Factors affecting pump selection are also discussed. Section 4 offers information on pump testing. Basic design of pumping stations is discussed in Section 5, offering design information for both large and small applications. Continuous regulation of submersible pump operation byfrequency control is described in Section 6. The concept of whole-life cost for pumps and pumping installations is presented in Section 7. Matters relating to pump commissioning are presented in Section 8, whereas pump operation and servicing is described in Section 9. Section 10 deals with pumping station control and monitoring. Appendix A offers information on the hydraulic characteristics ofcommon pipe components for pipeline loss calculations. Appendix B presents a method for the determination of sewage pumping station capacity and pump starting frequency. One objective of the book has been to make the contents easy to read and comprehend. The presentation is therefore enhanced with a large number of illustrations, providing examples of and complementary information on thematter at hand.

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Table of Contents

Table of Contents
1 1.1 1.1.1 1.1.2 1.2 1.3 1.3.1 1.3.2 1.3.3 1.3.4 1.3.5 1.4. 1.4.1 1.4.2 1.4.3 1.4.4 1.4.5 1.4.6 2 2.1 2.2 2.2.1 2.3 2.3.1 2.3.2 2.3.3 2.3.4 2.3.5 2.3.6 2.4. 2.5 Pump Theory ............................................. 7 The Head Equation .........................................7 Flow with Losses or Addition of Energy ....7 FluidFlowing from a Container .................. 8 The Basic Pump Equation ............................. 8 Pump Curve and Losses ...............................10 The Effect of Finite Number of Vanes ......10 Friction Losses Hf ..........................................10 Discontinuity Losses Hs ...............................10 Leakage Losses Hv .........................................10 OtherLosses ....................................................11 Cavitation and NPSH .....................................11 Definition of NPSH .......................................12 Reference Plane .............................................12 Required NPSH ...............................................12 Available NPSH ..............................................14 NPSH Safety Margin..................................... 15 Damming up of Suction Wells................... 15

3.3.2 3.3.3 3.4 3.4.1 3.4.2 3.4.3 3.4.4. 3.4.5 3.5 3.5.1 3.5.2 3.5.3 3.5.4 3.5.5 3.6 3.7 3.7.1

Pump Construction ................................. 16 General ............................................................16 Pump ................................................................18 Impellers...