A butterfly valve, also known as a flip valve, is a simple structure regulating valve used for the on/off control of low-pressure pipeline media. It is a valve in which the closing element (valve disk or butterfly plate) is circular and rotates around the valve shaft to achieve opening and closing.

Valves are used to control the flow of various types of fluids, including air, water, steam, corrosive media, sludge, oils, liquid metals, and radioactive substances. They primarily serve as cut-off and throttling devices in pipelines. The butterfly valve's closure member is a circular disc-shaped butterfly plate that rotates around its own axis within the valve body to achieve the purpose of opening, closing, or regulating the flow.