Abstract: A valve assembly comprising a rotary closure element which defines an axis of rotation and is selectively movable between a fully open position and a fully closed position. Mounted to and movable with the rotary closure element is an impedance assembly. The impedance assembly defines an inflow end and an outflow end, and comprises a plurality of tortuous passageways which extend from the inflow end to the outflow end. Also fully or partially defined by the impedance assembly is an enlarged flow opening which extends from the inflow end to the outflow end. The tortuous passageways and the flow opening are oriented relative to each other such that a portion of a flow through the valve assembly is directed into the tortuous passageways and a portion of the flow is directed through the flow opening when the closure element is in the fully open position.

Abstract: A valve assembly comprising a rotary closure element which defines an axis of rotation and is selectively movable between a fully open position and a fully closed position. Mounted to and movable with the rotary closure element is an impedance assembly. The impedance assembly defines an inflow end and an outflow end, and comprises a plurality of tortuous passageways which extend from the inflow end to the outflow end. Also fully or partially defined by the impedance assembly is an enlarged flow opening which extends from the inflow end to the outflow end. The tortuous passageways and the flow opening are oriented relative to each other such that a portion of a flow through the valve assembly is directed into the tortuous passageways and a portion of the flow is directed through the flow opening when the closure element is in the fully open position.