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 valve disc to automatically prevent backflow. It belongs to the category of automatic valves. Based on the movement of the valve disc, it can be classified into lift-type, swing-type, and butterfly-type designs. Among these, the lift-type resembles the structure of a globe valve but lacks a valve stem, while the swing-type features an inclined disc that rotates around an axis. This type of valve is widely used in petrochemical industries, water supply and drainage systems, and as bottom valves in pumping devices to prevent water hammer effects and medium backflow. When combined with a globe valve, it can achieve safety isolation functions.
