Factory production HH46X, HH48X, HH49X muffler slow closed valve series is available in a solid track drainage water, sewage, water and other media, both to prevent the backflow of the medium, and can effectively limit the damaging water hammer, guarantee safe use of the pipeline. It has a novel structure, small size, a light weight, small fluid resistance, sealed emblem, open and close smoothly, wear resistance, long life, oil pressure, slow closing from the media influence, better energy-saving effect and so on.