What Is the Purpose of a Valve Actuator?

Most of us know what a valve is, and how it controls the flow of liquid or air through a pipe or duct. A faucet is a basic valve.

You may be less familiar with a “valve actuator” which is the mechanism that controls the opening and closing of a valve. The valve actuator relies on a power source to control the valve at whatever interval and pressure needed for operation.

Valve actuators are a major component in the “flow” of industrial and everyday machinery. Read on to learn more about this important component in automation.

How Does a Valve Actuator Work?

A valve actuator works by controlling flow through a valve via a power source.

For example, if you need to mix two liquids in a certain ratio to achieve a product, each liquid flow would be controlled by a valve actuator. The actuator takes its cues from a control source, either human-driven, motorized, or automated. The control source determines how much flow each valve will allow to keep the ratio of the two liquids constant.

It’s important in processes like these that the valves are controlled precisely because when they are not, it costs money. In this example, in wasted fluids.

To maintain this precision in any kind of process flow, manufacturers choose from different types of valve actuators.

Types of Valve Actuators

There are four basic types of valve actuators. categorized by their movement and by their power source.

Quarter-Turn Fluid-Power Actuators

Also known as a pneumatic actuator valve, or a hydraulic valve actuator, these devices use fluid or compressed air to manipulate valves. A 90-degree turn of the actuator controls the valve. An opposing spring provides a means for emergency shut-down if needed.

This type of actuator is lower in initial costs, but more expensive to use, given the need for a clean compressed power source. But, they are a good choice when electric power is not available.

Quarter-Turn Electric Power Actuators

These actuators use electricity as their power source. A quarter-turn electric valve actuator is very compact, uses less energy, and is ideal for smaller valve applications. A battery backup attached allows for continued operation in a power failure.

Multi-Turn Actuators

Multi-turn actuators can be fluid/air-driven or electric, though electric is more common.

Multi-turn actuators are needed with linear-type valves, such as a globe valve. These types of actuators are used for large valve operations and work by driving gears that in turn drive a stem nut. The stem nut operates the valve.

These actuators have built-in fail-safe devices, and are very durable, standing up to pressure, water, and even explosion.

To learn more about the different types of valve actuators, read on here.

Choosing the Right Valve Actuator

The right valve and valve actuators make the difference in the ease and economics of any manufacturing process. Several factors to consider when choosing a valve actuator include:

  • the type of valve used
  • the valve size and torque needed
  • the power sources available
  • the operating environment

Working in tandem with a trusted company that specializes in flow control will help you determine the right equipment.

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