A valve actuator is a mechanism for opening and closing a valve. Manually operated valves require someone to adjust them directly. Actuators mean that the valve can be automated with no human interaction.

How they work?

An actuator is the control mechanism that is operated by an energy source. So valve actuators can work by using gas pressure, hydraulic pressure or electricity, which allows the valve to be adjusted remotely or rapid operation of large valves.

Types

Double Acting: These actuators have a double actuating configuration with air/liquid supplied to both sides of the piston, with one side being higher pressure which achieves the movement required to actuate the valve.
Spring Return: Actuators with a spring return configuration have air/liquid supplied to only one side of the piston, and the energy to move the valve comes from the spring on the opposite side.
Pneumatic: Pneumatic actuator utilizes compressed air to generate the operating energy. These actuators are quick to respond, but are not ideal for high-pressure environments.
Hydraulic: Hydraulic actuators use liquid as a means of applying pressure to the valve. They generally exert a large amount of force because liquid is not compressible, but limited in acceleration and speed.
Electric: Electric actuators use a power source, such as mains or battery to run the actuator. They use intricate electrical circuitry to program when the actuator operates.

Applications

Used for automation of industrial valves, actuators can be found in all kinds of process plants. They are used in waste water treatment plants, power plants, refineries, mining and nuclear processes, food factories and pipelines.