Centrifugal blower is a machine that relies on input mechanical energy to increase gas pressure and discharge gas. It is a driven fluid machine.

The centrifugal fan is based on the principle of converting kinetic energy into potential energy, using a high-speed rotating impeller to accelerate the gas, then decelerate, change the flow direction, and convert kinetic energy into potential energy (pressure). In a single-stage centrifugal fan, the gas enters the impeller from the axial direction, changes into the radial direction when the gas flows through the impeller, and then enters the diffuser. In the diffuser, the gas changes the direction of movement to cause deceleration. This deceleration effect converts kinetic energy into pressure energy.

The pressure increase of the high-pressure centrifugal blower mainly occurs in the impeller, and secondly occurs in the pressure diffusion process. In a multi-stage centrifugal fan, a refluxer is used to make the air flow into the next impeller, resulting in higher pressure.

Centrifugal blowers are widely used in water treatment projects such as urban sewage and industrial wastewater, as well as occupations and departments such as metallurgy, chemical industry, aquaculture, pneumatic transportation and mine flotation, to transport air or other non-toxic and non-corrosive gases. It can also be used for ventilation and induced air in boilers and industrial furnaces, cooling and ventilation in air conditioning equipment and household appliances, drying and selective delivery of grains; air source in wind tunnels and air cushioning and propulsion.

Centrifugal fan is essentially a variable flow and constant pressure equipment. When the rotating speed is constant, the theoretical pressure-flow curve of the centrifugal fan should be a straight line. Due to internal losses, the practical characteristic curve is curved. The pressure that occurs in the centrifugal fan is greatly affected by the change in intake air temperature or density. The pressure generated by the turbine fan for a given intake air volume and intake air temperature (air density.). For a given pressure and flow characteristic curve, there is a power and flow characteristic curve. When the blower runs at a constant speed, for a given flow rate, the required power increases as the intake air temperature decreases.