https://www.mstnland.com/products/lift-check-valves.html LIFT CHECK VALVES Lift check valves refer to a valve that automatically opens and closes the valve flap by relying on the flow of the medium itself to prevent the backflow of the medium. The check valve is an automatic valve whose main function is to prevent the backflow of the medium, the reverse rotation of the pump and the driving motor, and the discharge of the medium in the container. Check valves can also be used on lines supplying auxiliary systems where pressure may rise above system pressure.