<p>A centrifugal blower includes a main scroll portion and a scroll opening through which air is discharged. A transitional portion conducts air discharged through the scroll opening away from the blower. The transitional portion includes an internal passageway that provides for the smooth passage of air essentially without causing any abrupt changes in the direction of the flow of the air through the passageway. An impeller assembly can be mounted within the main scroll portion for rotation so as to circulate the air in a spiral path within the main scroll portion and force the air through the scroll opening and the passageway in the transitional portion. The impeller assembly can have a platen that has a perimeter and a plurality of impeller blades mounted at the platen for rotation with the platen. Each impeller blade can have a distal end that extends beyond the perimeter of the platen.</p>
