Check valves are two-port valves, meaning they have two openings in the body, one for fluid to enter and the other for fluid to leave. There are various types of check valves used in a wide variety of applications. Check valves are often part of common household items. Although they are available in a wide range of sizes and costs, check valves generally are very small, simple, or inexpensive. Check valves work automatically and most are not controlled by a person or any external control; accordingly, most do not have any valve handle or stem. The bodies (external shells) of most check valves are made of plastic or metal.

The installation of check valves should pay attention to the following items.

1. Do not allow the check valve to bear the weight in the pipeline, and the large check valve shall be independently supported so that it is not affected by the pressure caused by the piping system.

2. The direction of the medium flow should stay the same direction with the direction of arrow on the check valve.

3. Lift vertical petal check valve shall be installed on vertical pipe.

4. Lift horizontal petal check valves shall be installed on horizontal pipes.