• 1- Introduction to Control Valves and Fluid Flow 

  1.1    Purpose of a control valve 

  1.2   Choked Flow Conditions (Critical Flow) 

  1.3   Typical control valve applications 

  1.4   Requirements of control valves 

  2-Types of Control Valves 

  2.1   Broad classification of control valves 

  2.2   Sliding stem valves. 

  • Globe valve. 
  • Globe valve construction. 
  • Single port double port stem. 
  • Cage guided valve. 
  • Balanced & unbalanced plug. 
  • Gate valve construction. 
  • Diaphragm valve construction. 

  2.3   Rotary Valves. 

  • Butterfly valve construction. 
  • Ball valve types and construction. 

  2.4   Other types of control valves. 

  2.5   Siding stem packing types & material 

  2.6  Summary. 

• 3- Control valve Actuators & positioners 

  • Function of actuators. 
  • The Different types of actuators. 
    • Advantages & Disadvantages 
  • Selection of actuators & parameters to be consider 
  • Sizing of actuators & parameters to consider. 
  • Performance Tests on Actuators 
  • Force / Torque Demanded by valves 

  Actuator types – operation. 

  • The purpose of positioners 
  • How positioners linearize installed characteristics. 
  • Smart positioners. 

• 1. Control valves function testing 

   

  1. Test procedure to verify valve traveling. 
     • Details of test procedures. 
     • What are some of the things that are checked? 
  2. Setting limit switches on valve. 
  3.  Hydrostatic testing. 
     • Why valve Hydrostatic test is performed? 
     • ANSI standard for pressure test. 
     • ANSI standard for duration of the test.  
  4.  Valve seat leakage testing. 
     • Why valve seat leakage is performed? 
     • ANSI specifications class regarding seat leakage test. 
     • Control valve seat leakage classifications. 
     • Class VI max. Seat leakage allowable. 
     • Reasons for valve failed in seat leakage test. 
  5.  Capacity test. 
  6.  Fugitive Emissions. 

• Key issues for Control Valve maintenance. 

   

  5.1 Scope of Maintenance Activities. 

  • • • • • • Installation practices. 
            • Documentation and identification of the control valve  
            • Filing and record keeping. 
            • Cost of maintenance 
            • Control valve maintenance strategies 
            • Reactive. 
            • Preventative  
            • Predictive  
            • Troubleshooting and diagnostics. 
            • Setting up of control valves and positioners 
            • Servicing and replacement of valve parts. 

  5.2   Key maintenance tasks. 

  1. 1. 1.   Identify and test a new control valve.  
        2.   Stripping the valve for  inspection 
        3.  Inspections and replacement of seals and stem packing. 
        4.  Replacement of seat rings. 
        5. Changing plug and seat trim sets. 
        6. Servicing of the actuator and positioner. 
        7.  Setting up the valve for stroking and calibration 

         5.3   Isolation Standards for valve maintenance 

  • • • Single Block 
      • Double Block and Bleed 
      • Rated Spade or Spectacle Blind 
      • Disconnection or Line Removal 

Major problems facing in control valve & troubleshooting 

Cavitation and Flashing in Control Valves 

Cavitation phenomenon and problems 

• • Flashing of liquids. 
  • Methods of reducing cavitation. 
  • Selection guide for cavitation applications. 
  • Disc Stack Technology. 
  • Conclusion. 

Noise and Noise Reduction Methods

Sources of control valve noise