H44H and H44Y type swing check valves are automatically opened and closed by the force generated by the flow of the medium itself in the pipeline, belonging to an automatic valve. The check valve is used in the pipeline system, its main function is to prevent the reverse flow of medium, prevent the pump and its driving motor from reversing, and discharge the medium in the container. The check valve can also be used to supply the auxiliary system in which the pressure may rise above the main system pressure.