A butterfly valve refers to a type of valve whose closing element is a disc, which rotates around the valve shaft to achieve opening and closing. It mainly functions as a shut-off and throttling device in pipelines. Butterfly valves are primarily used to control the flow of various types of fluids, including air, water, steam, various corrosive media, mud, oil products, liquid metals, and radioactive media. Their main roles in pipelines are shut-off and throttling.