H44H, H44Y type rotary check valve is relying on the flow of the medium in the pipeline itself to generate the force and automatically open and close, belongs to a kind of automatic valve. Check valve is used in pipeline system, its main role is to prevent the media backflow, prevent the pump and its driving motor machine reversal, as well as containers of media discharge. Check valve can also be used to give which the pressure may rise to more than the main system pressure of the auxiliary system to provide supply pipeline.