The check valve is an automatic valve, mainly used to prevent the backflow of the medium, the reverse rotation of the pump and drive motor, and the release of the container medium. It relies on the flow of the medium itself to automatically open and close the valve disc, thereby preventing the backflow of the medium. The valve disc movement mode of the check valve is divided into lift type and swing type. The structure of the lift check valve is similar to that of the globe valve, except that it lacks the valve stem that drives the valve disc. The swing check valve has an inclined valve disc that can rotate around an axis, and its working principle is similar to that of the lift check valve.

Check valves are widely used in various systems, such as pipelines that provide supply to auxiliary systems where the pressure may rise above the system pressure. It is often used as a foot valve in a water pumping device to prevent the backflow of water. Check valves and stop valves are used in combination to provide safe isolation.

The advantage of a check valve is that it automatically prevents backflow of media without requiring additional energy or operation. However, its disadvantages are high resistance and poor sealing when closed.

In general, check valve is an important valve type that can effectively prevent the backflow of media and protect the safe and stable operation of the system.