A non-return valve (NRV), also known as a check valve, is a mechanical device used to allow fluid flow in only one direction. These valves contain a movable element that blocks the flow in the opposite direction, eliminating backflow.
Due to their simple design and few moving parts, non-return valves are extremely reliable and require minimal maintenance. The question is – which type of non-return valve and which material is most suitable for your application?
In this blog, we explain how a non-return valve works, the appropriate materials, suitable applications, and the pros and cons of each type.
Non-return valves enable fluid to flow freely in one direction and then automatically close when fluid flow is reversed. Based on their operational function, check valves are used in various applications, such as to:
When selecting which valve needs to be installed in your piping system, you need to consider the type of fluid, flow, temperature, debris, system pressure, installation, pipeline size, and available space. Additionally, think about how frequently you need to service it or replace it.
With these factors in mind, choose from the following common types of non-return valves:
Spring-loaded check valves can be installed in inline systems and in various orientations, including vertical pipelines where fluid flows downwards.
You can find stainless steel and brass spring check valves on our website.
You can find stainless steel, brass, and PVC swing check valves on our website.
Wafer-type check valves are compact and lightweight, making them ideal for space-saving installations between companion flanges.
You can find cast iron and stainless steel double door wafer check valves on our website.
Spring-loaded ball check valves are similar to an in-line check valve but instead of a disc, they utilise a ball. These are designed for high-pressure scenarios.
You can find PVC ball valves and brass ball valves on our website.
You can find stainless steel piston check valves on our website.
You can find uPVC flanged swing foot valves, uPVC lever swing foot valves, brass and stainless steel foot valves, on our website.
Selecting the appropriate valve material depends on several factors. Firstly, it must be compatible with the fluid that flows through the valve. For example, consider if that fluid is aggressive, contains abrasive debris, or is prone to extreme temperatures.
Next, consider the environmental conditions the valve will operate in accounting for exposure to harsh weather or fluctuating temperatures. Finally, factor in the system operating pressure. Various materials are used in the manufacturing of different types of check valves, including:
Stainless steel is highly resistant to corrosion, chemicals, and extreme temperatures. Usually, stainless steel valves are rated for a broader range of operating temperatures than brass or plastic alternatives. It is known for its strength and durability, making it ideal for industries such as oil and gas, chemical processing, and marine applications.
Brass is also a durable and corrosion-resistant material suitable for a wide range of applications. It offers strength, withstands high temperatures, and is commonly used in water supply systems and plumbing.
PVC is a lightweight and cost-effective option often used in water treatment, irrigation, and general-purpose applications.
Polypropylene is a cost-effective, rigid, and tough thermoplastic often used in water distribution systems. Unfortunately, polypropylene has poor bonding properties and can be more susceptible to UV degradation, meaning it isn’t suitable for applications of high UV penetration.
Each of these materials offers advantages and disadvantages so we recommend speaking with your supplier and engineer to confirm their compatibility with your system.
At Waterworks, our PVC Industrial Swing Non-Return Valves are great for preventing backflow in low-pressure or drainage systems. The access point at the top of the valve allows easy access for cleaning the valve and removing trapped debris. Additionally, the inner section of the valve can be removed and is a replaceable component.
Ultimately, choosing the right check valve will depend on the specific needs and requirements of your piping system, as well as the intended application. If in doubt, reach out to the friendly team at Waterworks or check out our full range of check valves. Download our new brochure to find out more about our PVC Industrial Swing Non-Return Valves.