Centrifugal fans is based on the kinetic energy is converted to potential energy principle, high-speed rotating impeller the gas to accelerate and slow down, change direction, and convert the kinetic energy into potential energy (pressure). Single-stage centrifugal blower, gas from entering the impeller axially, gas flowing through the impeller into radial, then into the diffuser. In the diffuser, gases change the flow direction resulting in deceleration, the slow conversion of kinetic energy into pressure energy.