Marine centrifugal fan is a kind of slave fluid machinery which relies on the input mechanical energy to increase the gas pressure and discharge the gas. Marine centrifugal fan is based on the principle of conversion of kinetic energy into potential energy, using high-speed rotation of the impeller to accelerate the gas, and then decelerate, change the direction of flow, so that the kinetic energy is converted into potential energy (pressure). Marine centrifugal fans are widely used for ventilation, dust removal and cooling of ships; ventilation and air induced in boilers; cooling and ventilation in air conditioning equipment and electrical equipment and inflation and propulsion of hovercraft.