AutoQuiz is edited by Joel Don, ISA's community manager.
Today's automation industry quiz question comes from the ISA Certified Control Systems Technician (CCST) program. Certified Control System Technicians calibrate, document, troubleshoot, and repair/replace instrumentation for systems that measure and control level, temperature, pressure, flow, and other process variables. Click this link for information about the CCST program. This question comes from the Level I study guide, Domain 3, Troubleshooting. Level I represents a professional who has a five-year total of education, training, and/or experience.
Control valves, which have a plug positioned by a stem, which slides through a packing gland, are often referred to as:
a) rotary motion control valves
b) linear stem motion control valves
c) ball-control valves
d) motorized control valves
e) none of the above
A rotary valve has a flow closure member that rotates in the flow stream to modify the amount of fluid passing through the valve.
A linear valve or a globe valve refers to the linear or straight-line movement of the plug and stem. Some valves use a movable part like a ball, a disk, a gate, in the flow path to modify the rate of flow through the valve.
The best answer to this question is B.
This globe valve is one kind of linear stem motion control valve.
