Butterfly uses a circular plate or an ankle operated disc for the opening position full or fully closed at a 90 ° angle. This disc remains in the middle of the flow, and connected to the ankle via the shaft. When the valve is closed, the disc is perpendicular with the flow direction, so that the flow is stagnated, and when the valve is open the wafer is parallel to the flow, so that substances can flow through the valve.
Batterfly valve has minimal turbulence and pressure drop. Valve it is great for on-off or throttling operation, and good for controlling the flow of large amounts of liquid or gas. However, these valves do not usually have good tightness, and should be used in situations / systems that have low pressure .