High-Performance Butterfly Valves are used in throttling ap- plications requiring large flow capacities and small installed footprints. They use a rotating eccentric disk to control flow through a pipe. The disk is generally operable through 90 de- grees and provides a linear flow characteristic. These valves have nominal sizes from DN50 to DN1800 (from NPS 2 to 72) and pressure class up to PN420 (CL2500 according to ASME) depending on the model.