A method to determine control valve dynamic requirements

ISA TECH/EXPO Technology Update Conference Proceedings

Volumn 422, Issue , 2002, Pages 397-406

  Langford, Cullen G ^a  

^a Cullen G Langford Inc   (United States)

Author keywords

Analysis; Control; Control valve; Dead band; Response; Specifications

Indexed keywords

INSTALLATION; PERFORMANCE; QUALITY CONTROL; SENSORS;

CONTROL LOOPS; CONTROL VALVE;

VALVES (MECHANICAL);

EID: 0036973867     PISSN: 10540032     EISSN: None     Source Type: Conference Proceeding    
DOI: None     Document Type: Conference Paper

References (11)

1. Buckley, P. S. "Techniques of Process Control", Wiley 1964.
2. Shinskey, F. G., "Process Control Systems", McGraw-Hill Book Company, 1967.
3. Murrill, P. W. "Fundamentals of Process Control Theory" ISA, 1981.
4. ANSI/ISA-75.02-1996, Control Valve Capacity Test Procedures.
5. ISA-75.11-1985 (R1996) - Inherent Flow Characteristic and Rangeability of Control Valves.
6. ISA-75.13-1996, Method of Evaluating the Performance of Positioners with Analog Input Signals and Pneumatic Output. "4.2.2 The positioner/actuator assembly shall be mounted on a valve or test rig that is designed to permit the implementation of tests with minimum friction (unless otherwise specified)," can be eliminated.
7. Coughran, Mark T., "Measuring the Installed Dead Band of Control Valves", ISA 1997, "Dead band specifications smaller than approximately 1/4% pose challenges for both design and testing. Continued efforts to optimize process plants will push control valve manufacturers to improve design of valves, actuators, and positioners. Efforts should be focused on obvious factors such as friction, actuator area, and positioner gain, but also on less-obvious factors. Phenomena that limit the installed dead band of some control valves-e.g., flow behavior-will be completely missed by bench testing. Realistic testing for dead band approaching 1/8% will require improvements to dedicated test facilities; plant testing will remain difficult except in those cases where noise and load disturbances.
8. ANSI/ISA-75.25.01-2000 - Test Procedure for Control Valve Response Measurement from Step Inputs.
9. ANSI/ISA-TR75.25.02-2000 - Control Valve Response Measurement from Step Inputs.
10. Wilson, John, "Trim Replacement Allows Utility To Reduce Minimum Load By 25MW", JSA2000.
11. Langford, Cullen G. "A Users View of Process Control and Control Valve Positioners", ISA 1996.