VALVE SIZING REFERENCE GUIDE //data/public/pdf/valve-sizing-maual.doc 1 of 43 10/10/2008 Norriseal – P.O. Box 40525 Houston TX 77240-052–- Ph: (713) 466-3552, Fax: (713) 896-7386 TABLE OF CONTENTS Introduction ....................................................................................................................................... 4 Valve Flow Terminology......................................................................................................................... 4 The Sizing Process................................................................................................................................ 5 Operating Conditions ................................................................................................................. 5 Fluid Properties.......................................................................................................................... 5 Rangeability ............................................................................................................................... 5 Cv and Flow Sizing Formulas ..................................................................................................... 6 CV Formulas for Liquid Flow CV Formulas for Vapor Flow CV Formulas for Two Phase Flow Flow Velocity Formulas .............................................................................................................. 7 Flow Velocity for Liquid Flow Flow Velocity for Vapor Flow Nomenclature............................................................................................................................. 8 Conversion to Cg and Cs ........................................................................................................... 9 Seat Leakage ..................................................................................................................................... 12 Actuator Sizing .................................................................................................................................... 12 P Tables................................................................................................................................. 13 Actuator Air Volume ................................................................................................................. 26 Application Guide for Cavitation, Flashing and Compressible Flow Services....................................... 27 Liquid Flow ..................................................................................................................................... 27 Cavitation ................................................................................................................................. 27 Cavitation Definition Cavitation Countermeasures Application of Norriseal 2700A Trims in Cavitation Service........................................... 28 Cavitation Avoidance Cavitation Tolerant Cavitation Containment Cavitation Prevention Application Summary.................................................................................................... 28 The Cavitation Phenomena .......................................................................................... 29 Fluid and Pressure Profiles Choked Flow and Incipient Cavitation Cavitation Damage Flashing .......................................................................................................................... 30 Flashing Definition Flashing Countermeasures Body Material Trim Selection Application of Norriseal 2700A Valves in Flashing Service ........................................... 31 Body Material Trim Selection The Flashing Phenomena............................................................................................. 31 Liquid Flow Velocity - Body Material......................................................................................... 31 Compressible Flow Noise .................................................................................................................... 32 Compressible Flow Noise Discussion Compressible Flow Noise Countermeasures Application of Norriseal 2700A Trims in Compressible Flow Applications................................. 32 Standard Trims DB I and DB II Multiple Orifice Trims Compressible Flow Velocity Limits //data/public/pdf/valve-sizing-maual.doc 2 of 43 10/10/2008 Norriseal – P.O. Box 40525 Houston TX 77240-052–- Ph: (713) 466-3552, Fax: (713) 896-7386 Two Stage Trims and Backpressure Orifices The Compressible Flow Noise Phenomena.............................................................................. 33 TABLES Table 1-Trim Rangeability...................................................................................................................... 6 Table 2-Cg & Cs Conversion Factors .................................................................................................... 9 Table 3-Fluid Properties ...................................................................................................................... 10 Table 4-FL Factors ............................................................................................................................... 11 Table 5-Flanged Body Inlet and Outlet Diameters ............................................................................... 12 Table 6-Allowable Seat Leakage Classes............................................................................................ 12 Table 7-Allowable P Ratings 2700A/E Cage Control Trim, Teflon Packing 9 Actuator....................... 14 Table 8-Allowable P Ratings 2700A/E Cage Control Trim, Teflon Packing 12 Actuator..................... 15 Table 9-Allowable P Ratings 2700A/E Cage Control Trim, Teflon Packing 16 Actuator..................... 16 Table 10-Allowable P Ratings 2700A/E Cage Control Trim, Teflon Packing 18 Actuator................... 17 Table 11-Allowable P Ratings 2700A/E Cage Control Trim, Grafoil Packing 9 Actuator .................... 18 Table 12-Allowable P Ratings 2700A/E Cage Control Trim, Grafoil Packing 12 Actuator .................. 19 Table 13-Allowable P Ratings 2700A/E Cage Control Trim, Grafoil Packing 16 Actuator .................. 20 Table 14-Allowable P Ratings 2700A/E Cage Control Trim, Grafoil Packing 18 Actuator .................. 21 Table 15-Allowable P Ratings 2700A/E Plug Control Trim, 12, 16 & 18 Actuators............................. 22 Table 16-Allowable P Ratings for Unbalanced Trim, No.9 Actuator ................................................... 23 Table 17-Allowable P Ratings for Unbalanced Trim, No.12 Actuator ................................................. 24 Table 18Allowable P Ratings for Unbalanced Trim, No.16 Actuator .................................................. 25 Table 19-Actuator Air Chamber Volume & Required Added Air to Actuate .......................................... 26 Table 20-Liquid Flow Velocity Limits.................................................................................................... 31 Table 21-Flow Coefficients, CV, for 2200/2220 Unbalanced Modified Percent. Plug Control................ 35 Table 22-Flow Coefficients, CV, for 2275A Unbalanced Modified Percentage Plug Control ................. 35 Table 23-Flow Coefficients, CV, for 2400/2420 Unbalanced Modified Percent. Plug Control................ 36 Table 24-Flow Coefficients, CV, for 2700A/E Balanced Quick Opening Cage Control.......................... 36 Table 25-Flow Coefficients, CV, for 2700A/E Balanced Linear Cage Control ....................................... 37 Table 26-Flow Coefficients, CV, for 2700A/E Balanced Equal Percentage Cage Control..................... 37 Table 27-Flow Coefficients, CV, for 2700A/E Balanced DB I Cage Control .......................................... 38 Table 28-Flow Coefficients, CV, for 2700A/E Balanced DB II Control................................................... 38 Table 29-Flow Coefficients, CV, for 2700A/E Balanced CAV II Cage Control....................................... 39 Table 30-Flow Coefficients, CV, for 2700A/E Balanced Modified Percentage Plug Control .................. 39 Table 31-Flow Coefficients, CV, for 2700A/E Balanced Quick Opening Plug Control........................... 40 Table 32-Flow Coefficients, CV, for 2700A/E Unbalanced Modified Percent Plug Control.................... 40 FIGURES Graph 1-Pressure Drop Profile ............................................................................................................ 41 Graph 2-Liquid Flow Relationship with Pressure Drop ......................................................................... 42 Graph 3-CAV II Flow Noise Attenuation............................................................................................... 42 Graph 4-Pressure Profiles, Single Stage and Three stage Trims ........................................................ 43 Graph 5-DB I & DB II Flow Noise Attenuation...................................................................................... 43 //data/public/pdf/valve-sizing-maual.doc 3 of 43 10/10/2008 Norriseal – P.O. Box 40525 Houston TX 77240-052–- Ph: (713) 466-3552, Fax: (713) 896-7386 INTRODUCTION variable such as fluid pressure, fluid level, Q A Control Valve performs a special task, flow rate or temperature CV where controlling the flow of fluids so a process P can be controlled. In addition to controlling Q=Flow rate and P=pressure drop across the flow, a control valve may be used to the valve. See pages 5 and 6 for the shut off flow. A control valve may be equations for liquid,