Check Valve

Check valve also commonly known as a non-return valve or a one-way valve, is a type of valve used to prevent the reversal of fluid flow in a piping system. It allows fluid to flow in only one direction, typically from the inlet port to the outlet port, and closes automatically to prevent backflow when the fluid pressure reverses.
Sedelon® mainly produces Check valves according to the standard of API 6D. (API 6D Check valves)
According to different design standards, Sedelon® provides you DIN Check valves as well.
Check valves are made of various materials, including forged steel, stainless steel, alloy, bronze, cast steel, and carbon steel. Sedelon® specializes in producing forged steel check valves according to API 602 standards and stainless steel check valves according to API 603 standards. Ceramic check valves are an alternative option made of non-metal materials, known for their abrasion resistance and hardness under high pressure and temperature. Special materials like Hastelloy, special steel, and special alloy are also used for specific applications. For highly corrosive media, duplex stainless steel or super stainless steel check valves are often chosen.
Check valves operate automatically without human intervention or external force and do not require hand levers or stems. The only exception is the stop check valve, which can stop fluid flow under external control when necessary. Based on their construction, check valves are classified into three types: lift, swing, and butterfly type. Lift check valves are suitable for continuous fluid flow and stop applications but can only be installed in horizontal pipes.The most common Check valves are Swing Check valves. When the valves are fully opened, the fluid receives only small resistance. The Butterfly Type Check valves also referred to as Disc Check valves have simple structure and good sealing, which can only be installed in horizontal pipes.
Other types of check valves exist beyond the common ones. A ball check valve utilizes a solid ball as its disc, differing from traditional designs. The duckbill valve, resembling a duck's beak, is typically crafted from rubber and serves as a backflow prevention device, especially in medical applications.

Check valves come with various connection types, including screwed, flanged, butt weld, socket weld, and wafer check valves. Bronze wafer check valves excel in highly corrosive environments. While check valves generally produce noise during operation, dual plate wafer check valves are an exception. These valves feature two spring-loaded plates that swing like butterfly wings as fluid flows. When the flow slows, the plates close via torsion springs before any flow reversal, preventing both water hammer and slam. This innovative design earns dual plate wafer check valves the moniker of silent check valves, making them highly efficient and versatile.
Sedelon offers a variety of valves tailored for diverse operational environments, particularly varying temperatures. Depending on the temperature, we utilize High Temperature Check valves, Low Temperature/Cryogenic Check valves, and Jacket Check valves to ensure optimal performance. Jacket Check valves assist in maintaining the line fluid's temperature, while High Nickel Alloy Check valves are suitable for high temperature applications. For high-pressure conditions, Sedelon's High Pressure Check valves are an ideal solution.
Pressure Seal Check Valves automatically adjust the pressure of the sealing ring to accommodate different internal pressures within the pipeline. This valve type is typically employed in high-temperature and high-pressure operating environments.
Dual plate Check valves are frequently used in applications that require stringent prevention of backflow contamination, such as safeguarding water supply lines from the return of potentially contaminated water.