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What Does a Check Valve Do?

Check valve

Water valves are important for controlling the flow of water in a system. One specific type of valve, called a check valve, has a special job: it lets water flow in one direction but stops it from flowing backward. 


Check valves play a vital role in plumbing and maintaining water systems. In this article, we will explore the functions of a check valve, explain its importance and provide insight into the different types of check valves available on the market.


Av-Tek Valves is dedicated to delivering exceptional products and services that enable you to build high-quality solutions for your community. Browse our catalog or call us at (385) 325-2504 or (801) 637-8541 to learn more about our offerings. You may also visit our blog page for more resources on high-quality valves and their applications.


What is a Check Valve?


A check valve, also known as a non-return valve or one-way valve, allows the fluid to flow in only one direction. It is designed to prevent backflow, the reverse flow of fluids in a pipeline, and ensure the unidirectional fluid flow in the piping system.


The history of check valves dates back to ancient times when they were used to control water flow in irrigation systems. Over time, check valves have become more sophisticated, and today, they are used in various industries, including oil and gas, chemical, water treatment, and HVAC systems.


How Do Check Valves Work?


Check valves use a simple mechanism to allow fluid to flow in one direction while preventing backflow. They consist of a valve body, a seat, and a disc or ball that closes the valve opening when fluid flow reverses. When fluid flows in the forward direction, the disc or ball moves away from the seat, allowing the fluid to pass through; meanwhile, when the fluid flow reverses, the disc or ball returns to its seat, blocking the flow and preventing backflow.


Types of Check Valves


Check valves come in different types, each with its unique design and application, as well as advantages and disadvantages. However, some of the most common types of check valves include:


  • Ball check valves: These valves use a ball that sits on a seat to allow fluid to flow in one direction but prevent backflow when the fluid flows in the opposite direction.
  • Inline check valves (Globe-Style Sliding Disc Check Valve): These valves are installed within the piping system and use a spring-loaded disc to allow fluid to flow in one direction and prevent backflow when fluid flows in the opposite direction.
  • Swing check valves (Butterfly Check Valve) : These valves use a swinging disc to allow fluid to flow in one direction and prevent backflow when fluid flows in the opposite direction.
  • Lift check valves: These valves use a piston or ball to lift off the seat, allowing fluid to flow in one direction but preventing backflow when the fluid flows in the opposite direction.
  • Tilting disc check valves: These valves use a tilting disc to allow fluid to flow in one direction and prevent backflow when fluid flows in the opposite direction.
  • Wafer check valves: These valves are installed between flanges and use a spring-loaded disc to allow fluid to flow in one direction and prevent backflow when fluid flows in the opposite direction.


What Are the Functions of a Check Valve?


Check valves are used in a wide range of applications, including water treatment plants, chemical processing, oil and gas production, food and beverage processing, and HVAC systems. Here are the key functions of a check valve that make it an integral components in many industries:


  • Prevents Backflow: The primary function of a check valve is to prevent the backflow of fluids in a piping system. It ensures that the flow of fluid occurs in one direction only, effectively blocking reverse flow. This is especially important in situations where backflow could cause damage, contamination, or interference with the intended flow direction.
  • Protects Equipment and Systems: Check valves help safeguard equipment and systems by preventing potential damage caused by reverse flow. They act as a barrier, preventing fluids from flowing back and causing issues such as pump damage, pipe collapse, water hammer, or contamination of sensitive components.
  • Maintains Pressure: Check valves assist in maintaining optimal pressure levels within a system. By allowing fluid to flow in the desired direction and preventing backflow, they help maintain the desired pressure conditions, ensuring efficient operation of pumps, regulators, and other pressure-sensitive equipment.
  • Enhances System Efficiency: Check valves contribute to the overall efficiency of a system. By preventing reverse flow, they eliminate the need for additional pumps or mechanisms to counteract backflow, thereby reducing energy consumption and operational costs.
  • Minimizes Water Hammer: Water hammer, characterized by sudden pressure surges or shockwaves in a system, can lead to pipe damage and system failure. Check valves help mitigate water hammer by preventing reverse flow and the subsequent pressure spikes that can occur.
  • Allows for System Isolation and Maintenance: Check valves provide a means of isolating sections of a system for maintenance or repairs. By closing off the valve, the flow of fluids can be stopped in a specific direction, allowing for safe and efficient maintenance procedures.


What To Consider When Selecting a Check Valve


Several factors should be considered when selecting a check valve for a specific application. Here are some of the key considerations:


Flow Rate and Pressure Drop Considerations


One of the primary things to consider when selecting a check valve is the flow rate and pressure drop of the fluid. The type of check valve selected should be able to handle the anticipated flow rate and pressure drop while minimizing head loss.


Material Selection Considerations


The material of the check valve is also an important factor, as it affects the compatibility of the valve with the fluid being transported. In addition, different materials have different chemical resistance and durability properties, and the selected material should be able to withstand the specific environment and conditions of the application.


Temperature and Pressure Limitations


Check valves also have specific temperature and pressure limitations that must be considered when selecting a valve. The valve should be able to withstand the maximum temperature and pressure of the fluid without failure or damage.


Installation, Maintenance, and Cost Considerations


Finally, when choosing a check valve, it’s important to account for the initial purchase cost, assembly expenses, maintenance fees, and ongoing running costs. Cost is typically a significant factor, following quality and functionality. While low purchase prices may seem attractive, they can result in high maintenance and running expenses. Also, a low-cost check valve that fails to perform its intended function can cause serious issues at a pumping station.


Check valves must be installed properly to ensure optimal performance and prevent failure. Certain types of check valves may require expensive modifications to the pipeline, which can increase assembly costs. Maintenance and repair expenses also tend to rise as the valve’s complexity increases. In some cases, complex solutions may necessitate the assistance of a professional.


Streamline Your System With Av-Tek Valves: The Solution for Efficient Flow Control


Check valves play a vital role in maintaining the efficiency and safety of fluid systems. By preventing backflow, protecting equipment, and maintaining pressure, these valves ensure the smooth operation of various industries, including water treatment, chemical processing, oil and gas production, and HVAC systems. Choosing the right check valve for your specific needs requires considering factors such as flow rate, pressure drop, material selection, and maintenance requirements.


Remember, a properly selected and well-maintained check valve can significantly enhance the performance and longevity of your fluid systems. Choose Av-Tek Valves and streamline your flow control with confidence, knowing you have a trusted solution for efficient and hassle-free operations.

Av-Tek Valves offers top-quality check valves, including sliding disc check valves and flanged ball check valves. Our products are designed to meet your needs in terms of lead time, quality, and easy maintenance. So if you are looking for a reliable and efficient check valve for your water system, contact us today or call (385) 325-2504 or (801) 637-8541 for more information.

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