Check Valves

A check valve, also known as a non-return valve or one way valve, is a mechanical device that allows fluid or gas to flow in one direction only and prevents backflow in the opposite direction. NRV valve is designed to automatically open and close in response to the pressure or flow of the fluid or gas, without requiring external control or power. ATO 1 inch, 2 inch, 4 inch to 12 inch check valves are commonly used in piping systems, water pumps, compressors, and other fluid handling equipment to prevent reverse flow, backpressure, and water hammer. 

4 Types of Check Valves

• Swing check valve: Swing type check valve has a disc or flap that swings open when the fluid flows in the correct direction and closes when the fluid flows back in the opposite direction.
• Ball check valve: This ball-type check valve uses a ball that sits on a seat to allow flow in one direction and prevent flow in the opposite direction.
• Wafer check valve: The wafer non-return valve is installed between two flanges and uses a disc that moves up and down to allow flow in one direction and prevent backflow.
• Foot valve: A foot valve for water pump is used to prevent backflow and maintain the prime in a pump suction line. It is typically installed at the bottom of a suction pipe or wellbore.

Materials of Non-Return Valves

• Stainless steel: This is a popular material for check valves due to its corrosion resistance, durability, and strength.
• Brass: Brass is commonly used for non-return valves in plumbing applications due to its corrosion resistance, ductility, and machinability.
• PVC: PVC check valves are used in applications where chemical resistance is required, such as in water treatment and chemical processing. UPVC and CPVC are both thermoplastic materials that are derived from PVC through chemical modifications.
• Cast iron: Cast iron non-return valves are used in applications where strength and durability are required, such as in industrial and municipal applications.

How to Choose the Right NRV Valve?

Choosing the right check valve for your application can be critical to ensure the efficient and reliable operation of your system. Here are some key factors to consider when selecting a check valve:

• Application: Consider the type of fluid, flow rate, pressure, and temperature of the system. The check valve should be able to handle these conditions without causing excessive pressure drop, cavitation, or erosion.
• Type of check valve: Select the appropriate type of nrv valve based on the flow direction, installation orientation, and system requirements. For example, a swing check valve is suitable for horizontal installations, while a lift check valve is better suited for vertical installations.
• Material: Choose the material of the check valve based on the properties of the fluid being transported, environmental conditions, and compatibility with other materials in the system. Consider factors such as corrosion resistance, chemical compatibility, and durability.
• Size: Select the appropriate size of the check valve based on the pipe diameter and flow rate of the system. 1", 1/2"..2".. 4" to 12" check valves are available on ATO.com.
• End connections: Choose the appropriate end connections of the nrv valve based on the type of piping system and the connection method (flanged, threaded, or welded).
• Maintenance and repair: Consider the ease of maintenance and repair of the check valve, including accessibility, availability of spare parts, and repair services.

What is a Non-Return Valve Used for?

1/2" to 12" non-return valve is used to allow the flow of fluids or gases in one direction only while preventing backflow in the opposite direction. Non-return valves are commonly used in piping systems to prevent damage to equipment, contamination of fluids or gases, and safety hazards. They are used in a wide range of applications, including:

• Pump discharge lines: Non-return valves are often used in pump discharge lines to prevent the backflow of fluid into the pump when it is turned off or when the system pressure drops below the pump discharge pressure.
• Steam systems: Non-return valves are commonly used in steam systems to prevent the backflow of condensate into the steam lines. This can help to prevent damage to steam equipment and ensure the efficient operation of the system.
• Water supply lines: Non-return valves are used in water supply lines to prevent the backflow of contaminated water into the clean water supply. This is especially important in industrial and municipal water systems.
• HVAC systems: Non-return valves are commonly used in heating, ventilation, and air conditioning (HVAC) systems to prevent the backflow of air or water into the system. This can help to ensure the proper operation of the system and prevent damage to HVAC equipment.
• Chemical processing: Non-return valves are often used in chemical processing applications to prevent the backflow of hazardous chemicals into the system. This can help to ensure worker safety and prevent environmental contamination.