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Control valves rarely receive much attention when everything is working normally. The process temperature stays steady, pressure behaves itself and production keeps moving.
Then the valve begins sticking.
Perhaps it overshoots, reacts too slowly or refuses to reach the commanded position. Suddenly, understanding actuators, positioners and valve characteristics becomes rather important.
The Udemy course Control Valves, Actuators & Positioners: Operation & Design explains how these devices work, how they are selected and why certain valve arrangements behave better in specific process applications. I believe it is a very good practical course for instrumentation technicians, maintenance professionals and engineers working around process-control systems.
[Control Valves, Actuators & Positioners : Operation & Design]
What Does the Course Cover?
Created by WR Training, the course currently contains nine sections, 71 lectures and approximately 3 hours and 26 minutes of video. Udemy lists a 4.6 rating from 187 reviews, more than 1,100 enrolled students and a most recent update in November 2025.
The curriculum covers:
- Control-valve construction and internal parts
- Globe, ball, butterfly and plug valves
- Two-port and three-port valve arrangements
- Valve flow coefficient, or Cv
- Linear, equal-percentage and fast-opening characteristics
- Diaphragm and piston actuators
- Rack-and-pinion and Scotch-yoke actuators
- Fail-open, fail-closed and fail-in-place operation
- Pneumatic, electro-pneumatic and digital positioners
- I/P converters
- Installation and commissioning
It is a compact course, but the subject coverage is surprisingly broad.
Understanding Valve Construction
The early sections explain the purpose of components such as the valve body, bonnet, trim, seat, plug, stem, packing and actuator.
Students also see 2D and 3D dismantling demonstrations. These visual examples help show how the internal components fit together, which is far more useful than staring at a cross-sectional drawing and pretending everything is immediately obvious.
The course then compares linear and rotary valves, including globe, ball, butterfly, plug and three-port mixing or diverting designs.
Actuators and Failure Modes
A major part of the course focuses on pneumatic actuators.
Students learn the differences between single-acting and double-acting designs, along with diaphragm, piston, rack-and-pinion and Scotch-yoke mechanisms. The lessons also explain how some actuator configurations can be converted between fail-open and fail-closed operation.
Failure position is not merely a technical detail.
When instrument air disappears, the valve must move to the safest position for the process—or remain in place when that is the preferred option. Choosing the wrong behaviour can turn a simple air-supply problem into a much larger incident.
Valve Characteristics and Sizing
The course introduces the valve flow coefficient Cv and shows how it relates to flow rate and pressure drop.
Students compare fast-opening, linear and equal-percentage characteristics while working through process examples involving heating systems, boiler-water control and steam heat exchangers. The material also explains why installing an oversized control valve can create poor control and excessive sensitivity at low valve openings.
This section should be especially useful for engineers involved in valve selection and process design.
Positioners and I/P Converters
The course explains when a positioner is needed and how it helps the valve reach the requested position despite friction, spring force and changing differential pressure.
Pneumatic P/P positioners, electro-pneumatic I/P systems and digital positioners are introduced. The digital-positioner section also mentions industrial communication options including HART, Foundation Fieldbus and Profibus.
Who Is This Course For?
The course should suit:
- Instrumentation technicians
- Process and control engineers
- Maintenance technicians
- Mechanical and piping engineers
- Plant operators
- Valve-maintenance personnel
Some engineering or field knowledge is helpful, but Udemy states that it is not mandatory.
Are There Any Downsides?
This is mainly a design-and-operation course. It does not provide extensive hands-on calibration using real smart positioners or detailed troubleshooting with manufacturer-specific software.
At just over three hours, certain topics move fairly quickly. Learners who need advanced control-valve sizing, cavitation analysis or SIL-related valve calculations will require additional specialised training.
Final Verdict
Control Valves, Actuators & Positioners: Operation & Design is a very good introduction to industrial valve operation and selection.
Its strongest feature is the way it connects valve internals, actuator behaviour, flow characteristics and positioners with recognisable process examples.
Check the current course price and availability here:
[Control Valves, Actuators & Positioners : Operation & Design]