A general guide to valve actuators
Valve actuators are mechanisms used to control how a valve functions. The valve allows for a measured flow of fluid from one section of a machine to another section. However, without the valve actuator, the valve becomes ornamental—it can do nothing.
4 types of valve actuators
The value actuator controls the function of the valve through one of four power sources:
Each of these power sources have pros and cons depending on the type, size and function of the valve.
Pneumonic valve actuator
The source of power for pneumonic valve actuators is converting air pressure into rotary or linear motion. They are a versatile option and are able to use a range of components to get the job done efficiently and effectively.
Some of these components include: rack and pinion components, a diaphragm-activated motion, or plug, butterfly or ball devices.
This valve actuator’s effectiveness lies in the change of air pressure. When air pressures going one direction the value opens. Send the air pressure the other way and the valve closes.
Hydraulic valve actuator
To work a hydraulic valve actuator requires fluid pressure being converted into motion. This type of valve actuator is not ideal for cold temperatures as temperature can adversely affect fluid pressure. Hydraulic valve actuators are usually found in dams and nuclear power plants.
Types of hydraulic valve actuators
Fluid power quarter-turn actuators are considered an extremely dynamic actuator because they can be used where electricity or other power supplies are not readily available.
Another type of hydraulic valve actuator is the multi-turn actuator. This is used if you need a multi-turn output to control a linear type of value. So, for example, globe or gate valves. And while an electric valve actuator is normally used, the hydraulic option is useful if there’s no electric power supply.
Electric valve actuators
Environmentally friendly, non-toxic, quiet and energy efficient, electric valve actuators provide clean, safe and simple movement. They are controlled with a motor to power the gears and a single or three-phase alternating current.
Types of electric valve actuators
Similar to the hydraulic valve actuators there is the multi-turn and quarter-turn actuators. The electric multi-turn actuator is the most common actuator used. This is for a couple of reasons:
- All accessories are included with this valve actuator.
- The actuator is environmentally and physically safeguarded. It’s compact housing can be submersible, watertight and explosion proof.
The quarter-turn electric actuator is similar to the multi-turn version. Where they differ is the quarter turn is ideal for smaller valves due to its compact nature.
Manual valve actuators
Whereas the other actuators are powered by electric, air or liquid, the manual actuator is operated by hand. A person must crank either a lever or wheel to move the actuator so it can open the flow of air or water.
The manual valve actuator is still used because:
- Easy to operate
- Less susceptible to error
- Relatively inexpensive
- Easier to repair than other types of actuators
Valve actuators and safety
Valve actuators are just as important as the valves, and they play a crucial role in safety. As technology improves, many actuators can be automated which helps to drastically decrease the risk of harm to people involved.
The valve and the actuator enable the efficient running of systems in a safe and effective manner. The right actuator, of course depends on the environment it’s being placed in as well as the intended use and size.
If you would like more information on valve actuators, please feel free to get in touch with our team.