4-79 low and medium pressure centrifugal fans: good aerodynamic performance, high efficiency, and smooth operation. Application: It can be used for indoor ventilation and air exchange in general factories and large buildings, and can also be matched with air conditioners for various functions such as cooling and heating. It can transport air and medium gases that do not self ignite, do not contain viscous substances, have a dust concentration of no more than 150mg/m³, and a working temperature of no more than 80℃.