List of Questions and answers on Control Valves and Accessories used in industrial measurement and control.
State the combinations of pneumatic actuator and globe valve body required
a) air to open action;
b) air to close action.
State and sketch the three flow characteristics for the most common globe
State a typical application for each of the three flow characteristics and
explain why it is the most appropriate selection for that application.
State the effect of unbalanced force on valve position and explain with an
example, how bench setting would correct this problem.
Briefly explain at least three advantages a positioner gives when it is used
in conjunction with a control valve.
Describe the fail state for a given valve.
Sketch and describe a system pump head vs flow curve set to define
installed valve differential conditions.
Explain, with a diagram, how a three-way solenoid valve can be used for
ON/OFF control of a pneumatic valve.
State the formula which describes a control valve Cv factor. What is the Cv
for a valve which will pass a water flow of 100 USGPM with a pressure drop
of 25 psi? What flow would this valve pass when the pressure drop is 49
State why it is often advisable to use different sized valves in parallel when
the process variable has a very large flow range.
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