Patent ID: 6886596

Claim:
A valve assembly, comprising: a rotary closure element defining an axis of rotation and selectively movable between a fully open position and a fully closed position; and an impedance assembly mounted to and movable with the rotary closure element, the impedance assembly defining an inflow end and an outflow end, and comprising: a plurality of fluid passageways of varying noise attenuating capability extending from the inflow end to the outflow end, at least some of the fluid passageways being tortuous and defining a series of turns which extend at generally right angles relative to each other, with the tortuous fluid passageways of the impedance assembly define differing numbers of turns; the impedance assembly and the closure element collectively defining a flow opening which extends from the inflow end to the outflow end; the impedance assembly being mounted to the closure element such that flow is applied initially to the tortuous passageways having a greater number of turns when the closure element is moved from the fully closed position toward the fully open position.