Abstract: A control system provides automated control of gas washout of a patient interface, such as a mask or nasal prongs. A gas washout vent assembly of the system may include a variable exhaust area, such as one defined by gears, radial exhaust revolvers and/or flow diverters for a conduit having a variable gas passage channel. The vent assembly may be attached substantially near or included with the patient interface. An actuator of the assembly, such as a solenoid, motor or voice coil, manipulates the vent assembly. The actuator may be configured for control by a processor to change the exhaust area of the vent assembly based on various methodologies including, for example, sleep detection, disordered breathing event detection and/or leak detection.

Abstract: A blower includes a housing including an inlet and an outlet, a stationary component provided to the housing, an impeller positioned between the inlet of the housing and the stationary component, and a motor adapted to drive the impeller. The housing and the stationary component cooperate to define a volute that directs air towards the outlet. The housing includes a separating wall constructed and arranged to divide the volute into a high speed airpath region and a low speed airpath region.