The product series of HH46X, HH48X, HH49X silence slow closing check valves can be used in the drainage pipelines transporting water, sewage, sea water and other media which can prevent the backflow of the media and effectively limit the damaging water hammer, so as to ensure the safety of pipelines. It has some characteristics such as novel structure, small size, light weight, small fluid resistance, reliable seal performance, smooth opening and closing, wearing resistance, long service life, oil pressure, slow closing without the influence of media and better energy-saving effect, etc.