A check valve, also known as a non-return valve, one-way valve, reflux valve, or isolation valve, is an automatic valve that relies on the pressure of the medium itself and the weight of the disc to automatically block backflow, belonging to the category of automatic valves. Its disc movement mechanisms include lift-type, swing-type, butterfly-type, among others. The lift-type is structurally similar to a globe valve but lacks a valve stem, while the swing-type features an inclined disc that rotates around a shaft. This type of valve is widely used in petrochemical industries, water supply and drainage systems, and as foot valves in pumping installations. It can prevent water hammer effects and medium backflow. When combined with a globe valve, it enables safety isolation functions.
