Actuators for Valves

Actuators are essential for the efficient and accurate operation of valves in a variety of industries. These electromechanical devices convert energy into motion, enabling valves to open, close, or regulate flow rates. Actuators are essential components of industrial systems, as they ensure precise control, automation, and safety. In this article, we explore the world of actuators for valves, including their various types, functions, and industrial applications.

Various Actuators for Valves

Electric Actuators

Electric actuators are commonly used because of their precise control, dependability, and simplicity of integration into automation systems. They utilise an electric motor to operate the motion of the valve, enabling precise positioning and control. Electric actuators can be divided into two primary categories:

Linear Electric Actuators

These actuators provide linear motion to linearly moving control valves, such as gate and globe valves. They use a screw or rod mechanism to convert the electric motor's rotary motion into linear motion.

Rotary electric actuators

These are used for rotating valves, such as butterfly valves and ball valves. They convert the rotary motion of the electric motor directly into rotational movement, allowing precise control over the position and passage of the valve.

Pneumatic Actuators

Pneumatic actuators use compressed air or gas to produce mechanical force for valve operation. They are well-liked due to their ease of use, rapid response, and high force-to-weight ratio. Two principal types of pneumatic actuators are distinguishable:

Single-Acting Pneumatic Actuators:

In single-acting pneumatic actuators, air pressure is only applied to one side of the actuator, while the return stroke is accomplished by a spring or other mechanical means. Typically, they are used in applications where the valve must fail in a particular position, such as fail-open or fail-closed configurations.

Double-Acting Pneumatic Actuators

Double-acting pneumatic actuators utilise air pressure to power both the opening and closing strokes of a valve. They are adaptable and frequently employed in applications requiring bidirectional movement or modulating control.

Hydraulic Actuators

Hydraulic actuators generate force and motion by utilising hydraulic fluid. They are well-known for their high force capacity, smooth operation, and capacity to manage heavy-duty applications. Large-scale industrial processes, such as oil and gas pipelines, power plants, and mining operations, frequently employ hydraulic actuators.

Elecro-hydraulic actuators

Electro-hydraulic actuators incorporate the advantages of both electric and hydraulic actuators. They employ an electric motor to drive a hydraulic pump, which generates hydraulic pressure to operate the valve. Electro-hydraulic actuators offer precise control and high force capabilities, and they are frequently used in applications requiring both force and precision.

Functionality and characteristics of actuators

Actuators for valves provide a variety of functionalities and characteristics that improve their performance and applicability:

a. Positioning Control: Actuators enable precise positioning control, allowing valves to be opened, closed, or altered to precise positions with precision and repeatability. This feature is essential for maintaining process efficiency, regulating flow rates, and achieving the intended fluid or gas control levels.

b. Modulating Control: Numerous actuators support modulating control, which allows the valve to be positioned at varying degrees of openness to continuously control the flow rate. In processes that require precise regulation, such as chemical processing, water treatment, and HVAC systems, modulating control is essential.

Actuators can be designed with fail-safe mechanisms to ensure system safety in the event of a power loss or actuator malfunction. Depending on the application and safety requirements, fail-safe configurations can be fail-open or fail-closed, permitting valves to assume particular positions when the actuator is inert.

Actuators can be incorporated with control systems, allowing for remote operation, monitoring, and automation. This feature improves system efficiency, reduces the need for manual intervention, and enables centralised control of complex industrial processes.

e. Feedback and Position Indication: Numerous modern actuators include position feedback mechanisms like limit switches, potentiometers, and encoders.