There are many different types of control valves, and each one is controlled differently. This blog post will share insights from valtek control valves distributors on how to control these devices. Read on to find out more!
Most processing plants have one or more control loops that keep the process operating safely and efficiently. For instance, a control loop might monitor and adjust the flow of natural gas coming into the plant and a plant processing natural gas. In case you need any spare part for your heavy machinery, such as cummins fan pulley, you can order them online.
What Are Control Valves?
Control valves regulate fluids such as gases, water, or oil flowing through a process system. The main components of control valves include the following:
Valve: The valve is the heart of the control valve that regulates fluid flow.
Actuator: An actuator is a device used to open and close the valve.
Before going further, let’s talk a bit about the PLC.
What Is A PLC?
A PLC is a programmable logic controller. It is a type of computer used to control a process system’s operations. A PLC is typically used in industrial applications. For instance, a PLC will send signals that control the operations of an actuator. In essence, the PLC is the brain of the operation and will ultimately control the function of the control valve.
Classes of Control Valves
There are two main classes of control valves:
Linear Motion: Linear motion control valves have an actuator that employs a linear motion to open and close the valve.
Rotary Motion – The rotary motion control valves, on the other hand, use a rotary motion.
The type of control valve you use will depend on the application. For instance, rotary motion control valves are often used in applications where the flow rate needs to be controlled precisely. Linear motion control valves are often used in applications where the fluid needs to be shut off quickly.
Now let’s look in detail at how control valves are controlled.
How Control Valves are Controlled
As previously said, the actuator is the component that controls the function of the control valve. There are three main ways actuators regulate control valves. Let’s look at them.
Pneumatic: A pneumatic actuator uses air under pressure to regulate the control valves. Usually, the actuator will be connected to an air compressor, supplying compressed air it uses to open and close the control valve.
The actuator will open or close the control valve once it receives a signal from the PLC controller.
A PLC (Programmable Logic Controller) is a type of computer used to control industrial processes. PLCs are widely used in manufacturing plants and process plants.
Electrical: An electrical actuator functions using an electric motor. Again the activity of the electrical actuator is controlled by the PLC.
Hydraulic: A hydraulic actuator is connected to a hydraulic compression pump that supplies hydraulic pressure opening and closing the control valve.
The type of control valve and, by extension, the actuator you use will depend on the application.
There are pros and cons to every type of actuator. Let’s look at some of the advantages and disadvantages of pneumatic actuators.
Advantages of Pneumatic Actuators
Fast – Pneumatic actuators are fast-acting. They can open and close quickly, which is important in applications where the fluid needs to be shut off quickly.
Economical – Pneumatic control valves are relatively cheap.
Disadvantages of Pneumatic Actuators
Limited power: If your system processes large fluid volumes, you may need a hydraulic or electric control valve. Pneumatic control valves have limited power and are not well suited for large-scale applications.
What of Hydraulic Control Valves? What are the advantages and disadvantages?
Advantages of Hydraulic Actuators
Safety: Hydraulic control valves are often used in applications where safety is a concern. They are easy to control and can be used to shut off fluid flow quickly in an emergency.
Forceful – Hydraulic control valves are very forceful. They can deliver a large amount of force, which is important in applications where the flow rate needs to be efficiently controlled.
Disadvantages of Hydraulic Actuators
Expensive – Hydraulic Actuators are more expensive than their pneumatic counterparts.
Finally, let’s also look at electrical control valves.
Advantages of Electrical Actuators
Precise – Electrical Actuators are very precise.
Clean – Electrical Actuators are clean. No hydraulic fluid or compressed air can leak out and contaminate the process.
Disadvantages of Electrical Control Actuators
Costly – Electrical Actuators are more expensive than pneumatic and hydraulic control valves.
With this overview of how control valves are controlled, you should understand the different types of control valves and the advantages and disadvantages of each.
Pneumatic, hydraulic, and electric actuators are all ways to regulate control valves. Each has its advantages and disadvantages that should be considered when deciding which type of actuator to use for a particular application. In general, pneumatic actuators are fast and economical but have limited power, while hydraulic actuators are forceful but expensive. Electric actuators are precise and clean but also costly. Ultimately, the best type of actuator to use depends on the application’s specific needs.