A basic introduction to Butterfly Valves Butterfly Valves get their name from the Butterfly appearance of the disc and stem. The design consists of a round disc that is attached to a shaft rotating 90°. When the disc rotates to be parallel with the flow, the valve is fully open. To close the valve, the disc rotates perpendicular to the

The unique triple offset of the valve means the seating is affected with almost zero friction. The disc lifts off the seat without dragging across the surface. Because of this feature, these valves could be placed through 500,000 cycles of operation without any degradation in seating performance. The diagram below illustrates the inclined conical sealing principle utilized by the triple