Centrifugal blower is based on the principle of kinetic energy converted to potential energy. Through the high-speed rotation of the impeller speed, The gas will speed up and then slow down. To change the gas flow direction, the kinetic energy is converted into potential energy (pressure). In single stage centrifugal fan, the gas from the axial impeller, changed into radial gas flows through the impeller, and then into the diffuser. In the diffuser, gas changed direction of flow and caused slow down, the deceleration function converts kinetic energy into pressure.