Butterfly Valve has a unique shape compared with other valve-valve. Butterfly uses a circular plate or wafer-operated with Ankel to fully open or close the position filled by an angle of 90 °. The wafer is fixed at the center of the flow, and linked to Ankel through the shaft. When the valve is closed, the wafer is perpendicular to the direction of flow, so that the flow of unstoppable, and when the valve is open wafer parallel / aligned with the flow, so that the substance can flow through the valve.