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Contents
List of Figures, v
List of Tables, vii
Foreword, ix
Acknowledgments, xi
Chapter 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1Scope, 2Discussion of Torque Calculations, 2Uncertainty and Diameter Assumptions, 3Discussion of Head Loss, Choking, and Cavitation, 4Butterfly Valve Design, 5System Conditions, 7Nomenclature, 8References, 13
Chapter 2 Valve Torque . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15Definitions, 15Torque Components, 20Seating Torque, 24Packing and Hub Torque, 26Bearing Torque, 28Center of Gravity Torque, 30Hydrostatic Torque, 31Dynamic Torque, 33Shaft Offset or Eccentricity Torque, 36Other Components of Torque, 39System Characteristics, 44System Analysis and Example Calculations, 45Constant Head Source Methodology, 46Constant Head Source—Example, 48Variable Head Source Methodology, 52References, 53
Chapter 3 Valve Head Loss . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .55Definitions, 55Head Loss Calculations, 57Reducer Installations, 58Energy Calculations, 59References, 60
Chapter 4 Valve Cavitation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61Definitions, 61Predicting Cavitation, 62Methods for Reducing Cavitation, 66References, 66
iiiCopyright © 2012 American Water Works Association. All Rights Reserved.
©
Chapter 5 Valve Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67Testing Requirements, 67Flow Test Procedure, 69Seating/Unseating Torque Test Procedure, 73References, 75
Chapter 6 Valve Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77Actuator Sizing, 77Extended Bonnet Installation, 78Effects of Pipe Installations, 80Typical Range of Coefficients, 81Cautions, 84Summary, 85References, 86
Index, 87
List of Manuals, 91
ivCopyright © 2012 American Water Works Association. All Rights Reserved.