The check valve is a type of valve, also known as a non-return valve or check valve. Its function is to control the unidirectional flow of fluid in the pipeline and prevent reverse flow of fluid. When the pressure of the fluid exceeds the set opening pressure of the valve, the valve opens to allow the fluid to pass; when the pressure of the fluid is lower than the set opening pressure, the valve closes to prevent reverse flow of fluid. Check valves are widely used in water, gas, steam and other fluid pipeline systems to ensure the one-way flow of fluids and protect the safe operation of equipment and pipelines.

Check valves are divided according to structure and can be divided into three types: lift check valve, swing check valve and butterfly check valve:

•  Lift check valves are divided into two types: vertical and horizontal.

•  Swing check valves are divided into three types: single-disc type, double-disc type and multi-disc type.

•  The wafer check valve is straight-through.
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