In general, blowers are used in air cleaners, fans, and the like, and used industrially in air conditioner systems, various types of air intake and exhaust systems, and the like. Blowers can be classified as axial flow blowers, centrifugal blowers, or mixed flow blowers, depending on the characteristics of flow passing through the impellers thereof.
Among the above-mentioned blowers, centrifugal blowers allow the flow of air to occur, such that intake flow is generated in a direction of an axis of rotation thereof and exhaust flow is generated in a direction perpendicular to the axis of rotation, and is applied to common household air cleaners.
The centrifugal blower has a single-side intake method, in which intake flow is generated from one side of the axis of rotation, and a dual-side intake method, in which intake flow is generated from both sides of the axis of rotation.
Generally, such a centrifugal blower includes a centrifugal fan having a plurality of wings disposed in a circumferential direction thereof, and a scroll casing configured to surround the centrifugal fan while having an outlet guiding, to one side of the scroll casing, air discharged in the circumferential direction of the centrifugal fan.
However, a centrifugal blower, according to the related art, has a problem in that noise by air friction is generated and air volume is reduced, due to the imbalance of flow discharged from the outlet of the scroll casing.
In particular, the end of the outlet of the scroll casing is expanded, allowing for an increase in an opening area thereof, in order to diffuse air, and due to an expansion effect, the imbalance of exhaust flow is significantly generated.