The world of valves can be confusing, with many types available for various applications. Today, we will dive into the differences between check and control valves. Although both valves are commonly used in piping systems, they have key differences that make them suitable for different purposes. By the end of this article, you’ll know which valve is best for your application!
Difference Between Check Valve and Control Valve
Purpose and Functionality
Check valves have a critical role in preventing backflow in piping systems. They are known for their simple design and offer full flow without requiring any outside energy source. Unlike control valves, check valves are automatic and don’t require any manual intervention to work. They operate based on the pressure of fluid passing through them; when the pressure in the line decreases, the valve closes to prevent backflow. Control valves, on the other hand, are used to control the flow rate, pressure, or level of a fluid in a line. They operate by regulating the flow rate of fluid passing through them, which can be done manually or automatically.
Types of Valves
Check valves come in different types, including swing, lift, ball, and piston check valves. Each type offers unique advantages; the valve choice depends on the application. Control valves are also available in several types, including globe, diaphragm, butterfly, and ball valves. Each type provides different features, benefits, and drawbacks to suit various environments.
Design and Construction
Check valves consist of a valve body, disc, and spring or weight. The closure mechanism of check valves varies depending on the check valve type. Control valves, on the other hand, have more complex designs and consist of a valve body, valve actuator, and valve positioner. They may also have associated piping and instrumentation to provide control.
Applications
Check valves are commonly found in water treatment plants, petrochemical facilities, and oil production sites. They are useful in preventing reverse flow in plumbing systems by reducing water hammer and other related issues. Control valves, on the other hand, are commonly used in HVAC systems, chemical plants, and oil and gas refineries. They play a vital role in controlling these systems’ flow rate and pressure, resulting in the precise control of temperature and pressure levels within the system.
Maintenance and Cost
Check valves are relatively low cost and require less maintenance than control valves. However, they can be prone to failure, especially if they are frequently used or if they are exposed to severe conditions. Control valves, on the other hand, are more expensive compared to check valves due to their complex design and construction. They also require periodic maintenance to ensure proper operation, resulting in a higher lifetime cost than check valves.
Conclusion:
In conclusion, check and control valves are essential in piping systems. The choice of which valve to use depends on the specific application. If the primary concern is preventing backflow and preventing water hammer, a check valve is the best choice. On the other hand, a control valve is the best choice for better control of flow rate and pressure in a piping system. Regardless of the situation, it’s important to choose the right valve, as it can significantly impact the piping system’s safety, efficiency, and effectiveness.
