This butterfly valve is suitable for the pipelines of fire fighting, petroleum, chemical industry, food, medicine, pharmacy, water and electricity, ships, water supply and drainage, smelting and energy, etc. It can be used as regulating and intercepting equipment on various corrosive and non-corrosive gas, liquid, semi-fluid energy and solid powder pipelines and containers. It is especially suitable for high-rise building fire fighting systems and other pipeline systems that need to display valve opening and closing status.