author: ZHIPENG VALVE GROUP

2025-03-10

Control valve selection can be challenging even for experienced technicians. You should be familiar with regulation technologies and the types of control valves available.

In the next section, I will describe what a control valve is and the different types of valves available.

Read on to learn more about the technology behind control valves, their types and applications in industry.

What Is a Control Valve?

A control valve is an electrically operated device that is used to regulate or manipulate the flow of fluids, such as gas, oil, water, or steam, through a system.

The control valve is by far the most common final control element used today in industry, that is to say, it is a critical part of a control loop, and it is an example of a final control element.

How Does a Control Valve Work?

The purpose of the control valve is to control the flow of liquid or gas, either fully (on/off), or slightly (modulated).

Modulating valves change the size of the opening through which the media flows by opening or closing slightly. They can also be fully closed or fully open.

The valve actuator will not operate by itself. It must receive a signal from an outside source, such as one of the following:

• Pneumatically actuated control valve: a pneumatic pilot or liquid level controller.

• Electrically actuated control valve: an electric pilot, Programmable Logic Controller (PLC), or Remote Terminal Unit (RTU).

Control Valve Types and Categories

Control valves are critical components in various industrial processes and systems, used to regulate the flow of fluids (liquids or gases) by varying the valve’s opening. They come in various types and categories, each designed for specific applications and performance requirements. Here are some common control valve types and categories:

1.Based on Action and Functionality:

• Linear Control Valves: These valves provide a linear relationship between the valve’s stem position and the flow rate. Globe valves are a common example of linear control valves.

• Rotary Control Valves: These valves use a rotary motion to control flow. Ball valves and butterfly valves fall under this category.

2.Based on Valve Body Design:

• Globe Valves: Globe valves have a globe-shaped body and a linear motion plug or disc. They are suitable for precise control and throttling applications.

• Butterfly Valves: Butterfly valves have a disc-shaped closure element that rotates to control flow. They are often used for larger pipe sizes and where quick shutoff is needed.

• Ball Valves: Ball valves use a spherical ball with a hole through it to control flow. They are known for their tight shut-off capabilities.

• Plug Valves: Plug valves use a cylindrical or tapered plug to control flow. They are suitable for applications requiring simple on-off control.

3.Based on Flow Characteristics:

• Equal Percentage Valves: These valves provide a change in flow rate proportional to the percentage change in valve position. They are commonly used for applications where the process variable varies widely.

• Linear Percentage Valves: These valves provide a linear change in flow rate with respect to valve position. They are used when a consistent linear response is required.

• Quick Opening Valves: Quick opening valves provide rapid changes in flow rate at initial valve opening. They are often used for on-off applications.

4.Based on Actuator Type:

• Pneumatic Control Valves: These valves are operated using compressed air or gas to control the valve position.

• Electric Control Valves: Electric actuators are used to operate these valves, making them suitable for remote and automated control.

• Hydraulic Control Valves: These valves use hydraulic fluid to actuate the valve’s position.

5.Based on Valve Trim:

• Sleeve or Cage Guided Valves: These valves have a cage or sleeve around the trim to guide the flow and reduce vibrations and noise.

• Single-Seat and Double-Seat Valves: Single-seat valves have one sealing surface, while double-seat valves have two. Double-seat valves can provide better shut-off capabilities.

6.Specialized Control Valves:

• Three-Way Valves: These valves have three ports and are used to divert or mix flows in a system.

• Control Valves for Cryogenic Applications: These valves are designed to handle extremely low temperatures.

• Control Valves for High-Pressure Applications: These valves are built to withstand high-pressure environments.

7.Categories Based on Application:

• Pressure Control Valves: Used to control and maintain pressure in a system.

• Temperature Control Valves: Designed to regulate temperature by adjusting fluid flow.

• Flow Control Valves: Used to control the rate of fluid flow in a pipeline.

• Level Control Valves: Designed to maintain a constant level of fluid in a vessel or tank.

These are some of the common types and categories of control valves, each with its unique features and applications. The choice of control valve depends on the specific requirements of the process or system it is used in, including flow rate, pressure, temperature, and control precision.

Industry Applications of Control Valves

Control valves have a wide variety of functions ranging from regulating the flow, pressure, and temperature of fluids (and other substances), to controlling air, steam, glycol mixes, and chemicals, based on predefined settings for fluid flow, pressure, and temperature.
Essentially, control valves can be found in any refinery, chemical manufacturing, or other industry. These valves are used for controlling the quantity of the process and the consequent outcome of the process.

• The flow of fluid in a loop is regulated by control valves.

• A transmitter and a controller are used at the start of the loop to compare the current flow level and the desired flow level.

• A control signal is sent by the controller to the device that controls the valve (valve).

• A control valve is used when fluid flow is to be reduced (or when it is to be increased).

• In order to ensure that the desired level of flow is achieved, the valve opens or closes accordingly.

In various industries, there are a variety of types of control valves and applications that can be found. They can be found in industries such as food and beverage, oil and gas, pipelines, biopharmaceuticals, and many other fields.

Conclusion

We hope this guide helps you find the right device for your task after reading this guide on control valve types and applications.