Flow control manual
Valmet
This manual is intended to give an overview of the role of control valves in the behavior of a process control loop. It consists of information on fluid behavior, valve installed performance, and the theory and practice of control valve sizing.
Table of contents
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Foreword
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1. Introduction to pipeline flow
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2. Control valve installed performance
- 2.1 General
- 2.2 Operating conditions
- 2.3 Selecting a control valve
- 2.4 Control valve flow characteristics
- 2.4.1 Inherent flow characteristics
- - A. Quickopening inherent flow characteristics
- - B. Linear inherent flow characteristics
- - C. Equal percentage inherent flow characteristics
- 2.4.2 Installed flow characteristics
- 2.4.3 Installed gain
- 2.4.4 Calculation methods
- - Procedure
- - Process model and DPm selection
- - A. Liquid flow
- - B. Gas flow
- 2.4.5 Control valve accuracy
- 2.4.6 Control valve characterization
- 2.4.1 Inherent flow characteristics
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3. Liquid flow
- 3.1 General
- 3.2 Sizing equations for liquid flow
- - Factors FF, FR, FP, and FLP
- 3.3 Cavitation and flashing
- 3.3.1 Cavitation phenomenon
- 3.3.2 Investigating the existence of cavitation
- 3.3.3 Flashing of liquids
- 3.4 Cavitation and hydrodynamic noise abatement
- - Velocity control
- - Acoustic noise and bubble size control
- - Location control
- - Flat baffle plates
- - Orifice plates
- - Sizing baffle and orifice plates
- - Example of noise and cavitation abatement
- 3.5. Hydrodynamic noise prediction for valves
- 3.6 Hydrodynamic noise prediction for baffle and orifice plates
- 3.7 Recommended flow velocities for liquids
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4. Gas and steam flow
- 4.1 General
- 4.2 Sizing equations for gas and steam flow
- 4.3 Aerodynamic noise
- 4.3.1 Aerodynamic noise generation
- 4.3.2 Aerodynamic noise prediction
- - Calculation method to predict aerodynamic noise levels
- 4.4 Atmospheric venting
- 4.5 Aerodynamic noise abatement
- 4.5.1 Source treatment
- - Velocity control
- - Acoustic control
- - Location control
- - Diffusers
- - Attenuator plates
- - Source treatment examples
- 4.5.2 Path treatment
- - Silencers
- - Insulation
- - Heavy downstream pipe schedule
- 4.5.1 Source treatment
- 4.6. Recommended flow velocities and limits for noise levels
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5. Multi-phase flow
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- 5.1 General
- 5.2 Two-phase flow of liquid and gas
- - Sizing equations
- - Choked flow
- - Accuracy
- 5.3 Pulpstock
- 5.3.1 Studies about pulpstock
- 5.3.2 Pulpstock behavior in control valves
- - The effect of differential pressure on pulp flow
- - The effect of consistency on pulp flow
- - The effect of valve diameter and style on pulp flow
- - The effect of other factors on pulp flow
- 5.3.3 Control valve sizing for pulpstock applications
- 5.4 Slurries
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6. Mathematical simulation of control valve behavior
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- 6.1 General
- 6.2 Use of simulation
- 6.3 Mathematical model of control valve
- 6.4 Control valve simulation program
- 6.5 Friction model
- 6.6 Testing and implementing the simulation program
- - Testing position control
- - Studies of an installed control valve
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Appendices
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- A Sizing examples
- B Conversion tables
- C Steam
- D Superheated steam
- E Physical constans
- F Vapor pressure curves
- G Compressibility factor z
- H Pipe tables
- I Pressure drop in steel pipes
- J Correction coefficient k for pulp flow
- K Noise prediction aspects
- L Control valve performance terminology
- M Manifold design guidelines for valves
- List of symbols
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- A Sizing examples
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