My factory production HH46X, HH48X, HH49X silencing slow close check valve series products available in the media such as water, sewage, sea water drain, can prevent the backflow medium, can effectively restrict the destructive water hammer again, ensure the safety of the use of the pipeline. It has the advantages of novel structure, small volume, light weight, small fluid resistance, reliable sealing, smooth opening and closing, wear resistance, long service life, hydraulic, hydraulic slowly-closing is not affected by medium, has good energy saving effect, etc.