H44W, H44Y stainless steel check valves are automatically opened and closed by the force generated by the flow of medium in the pipeline, which belong to automatic valves. The check valve is used in the pipeline system, and its main function is to prevent the reverse flow of the medium, prevent the reverse rotation of the pump and its drive motor, and discharge the medium in the container. The check valve can also be used to supply makeup to the auxiliary system where the pressure may rise above the main system pressure.