Hydraulic slow-closing butterfly check valve is mainly used in the pump outlet of industrial water supply and sewage treatment plants to prevent the backflow of media in the pipe network, automatically eliminate destructive water hammer and ensure that the pump and pipeline are not damaged. Hydraulic slow-closing butterfly check valve is mainly composed of valve body, valve flap, buffer device and miniature adjustment valve. Hydraulic slow-closing butterfly check valve has novel structure, small volume, low fluid resistance, smooth operation, reliable sealing, wear resistance and good buffer performance. It is the best product for industrial water and urban sewage discharge.