Silent check valve is suitable for water supply and drainage pipe. The valve disc is guided by the central shaft at both ends of the import and export ,which is flexible in opening and closing and can be installed horizontally or vertically . The valve disc is loaded by air spring, and its quick closing can effectively eliminate the water harmmer, with good sealing performance and no noise. It has the advantages of small volume, light weight , low fluid resistance, fatigue resistance and long life.