the butterfly valve opening and closing part is a disc-shaped butterfly plate, which rotates around its own axis in the valve body to achieve the purpose of opening and closing or adjusting. Hard seal butterfly valve is suitable for pipes conveying corrosive and non-corrosive fluid media in producer, gas, steam, natural gas, city gas, cold and hot air, chemical smelting engineering and power generation environmental protection system, and is used to regulate and cut off the flow of media. Hard seal butterfly valve can be divided into manual hard seal butterfly valve, pneumatic hard seal butterfly valve and electric hard seal butterfly valve.