The check valve is installed on the outlet pipe of the pressurized water pump of industrial circulating water supply and drainage, urban water supply and drainage, high-rise buildings, sewage and hotels, to prevent the back flow of the medium and eliminate the destructive water hammer. Check valve. In the design, the requirements of the use environment are fully considered, to achieve no vibration, no noise, stable operation, long service life, to ensure a quiet hotel and residential environment, and have energy-saving effects.