Wednesday, September 24, 2008
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Control valve has been widely used in Chemical & Process Plant for material feeding control and operating condition control. Today control valve technology is high in reliability and availability and long life span. It is a very mature technology. There are many handbooks and articles presented in earlier post "Useful Documents Related to Control Valves" and they are available for download.
Recommended :Besides theory and practical knowledge in articles, there are still many frequently asked questions related to control valve. Following is a list of frequently asked question (FAQ) related to control valve. It is pretty useful especially to young engineer.
The question includes :
- What is CV ?
- What is the difference between actual, standard and normal flow rates for gases ?
- What is Cavitation ?
- What is flashing ?
- What is choked flow ?
- How can cavitation damage be contained ?
- How can flashing damage be contained ?
- Is the velocity of a fluid in a control valve critical ?
- What is the difference between a liquid, a vapour and a gas ?
- What is a desuperheater and how does it differ from an attemporator ?
- Why do different control valves have different characteristics ?
- Definition of linear and equal percent characteristic ?
- What is the difference between installed and inherent characteristics ?
- Why are control valves sometimes very noisy ?
- Can two control valves be used in series in high pressure drop applications ?
- Can two control valves be used in parallel to handle high turndown applications ?
- What is the difference between rangeability and turndown ?
- What process data is required to size a control valve ?
- What is incipient cavitation?
- What is the difference between a diffuser plate and a choke ?
- What is a field reversible actuator ?
- Will separable flanged valves seal in a pipeline ?
- What is the trim in a control valve ?
- What is meant by Critical Pressure and Critical Temperature ?
- Is flow through a control valve turbulent or laminar ?
- What is vapour pressure ?
- Specific Gravity is the ratio of the density of a liquid to the density of water – What is Specific Gravity of a Gas ?
- What is meant by Cryogenic ?
- What materials can be used for Oxygen Service ?
- Why do Oxygen valves require degreasing ?
- Are safety valves, regulators and isolating valves all examples of control valves ?
- Why do some control valve actuators have a small internal fail action spring and some are external and larger ?
- Why is live loading sometimes offered on valves ?
- Why is reduced trim required in control valves ?
- How is the characteristic determined in a globe valve ?
- What effect does the positioner cam have on the valve characteristic ?
- Why is Energy dissipation an important factor in control valve selection?
- Useful Documents Related to Control Valve
- FREE & Reliable Control Valve Sizing Software
- Understand Droop Effect in Self-regulated Control Valve
- WELKER Jet Contorl Valve Handbook
- How to apply valve equation in HYSYS Depressuring ?
- Useful Documents Related to Pressure Relief Valve (PRV) - Part 1
- 12 Features required for Shutdown Valve (SDV)
Labels: Control valve