Ball valve is used to on/off the medium in pipeline and is widely used in petroleum refining, chemical, electric power, long-distance transportation pipeline, paper making, pharmaceutical, water conservancy, municipal, steel, etc. Special consideration is taken to strength, safety and resistance to harsh environment during designation. It's suitable for various corrosive and non-corrosive mediums. Different materials may be selected for transportation of water, steam, oil, natural gas, nitric acid, acetic acid, oxidant and urea. Ball valve has compact structure and reliable sealing. Its sealing surface and spherical surface are closed normally, which make it resistant to flush erosion from the medium and easy to operate and repair.