Respiratory mask assembly

摘要

A flow regulation vent for venting washout gas to atmosphere and for regulating flow from a pressurized gas supply includes a fixed portion adapted to engage a gas supply conduit; a spring force biased movable portion in communication with the pressurized gas supply; and a hinge pivotally connecting the movable portion to the fixed portion. The fixed portion has a gas flow orifice and the movable portion is pivotally movable between 1) a relaxed position, below a specified operating pressure to establish a first gas washout flow area, and 2) a fully pressurized position. At or above the specified operating pressure, the pressurized gas pivots the movable portion adjacent the fixed portion to cover at least a portion of the gas flow orifice and establish a second gas washout flow area. The second gas washout flow area is less than the first gas washout flow area.