The SGON Welding Type Butterfly Valves is a simple regulating valve, and it can also be used for switch control of low pressure pipeline medium. Hard seal butterfly valves mainly cut off and throttling on pipelines. The butterfly valve opening and closing part is a disc shaped butterfly plate which rotates around its own axis in the valve body so as to achieve the purpose of opening or closing or regulating. The hard sealed butterfly valve is suitable for the pipes of the furnace, gas, steam, natural gas, city gas, cold and hot air, chemical smelting engineering and power generation environmental protection system to convey various corrosive and non corrosive fluid medium, which can be used to regulate and truncate the flow of the medium.