Model SWF-I mixed-flow ventilator is a novel and intermediate fan between axial-flow fan and centrifugal fan. It absorbs the advantages from both fans. Its wind pressure is higher than the same machine number axial-flow fan and flow larger than the same machine number centrifugal fan. It haw the advantages such as wide and effective operational zone, high efficiency etc. This fan is widely applicable for the ventilation and exhaust system in the office building, hotel large-size high-grade civil purpose architectures etc. It can also be used for ventilation and air-exchange in the mining and industrial enterprises such as freezing house, textile and so on in order to replace for the low-pressure centrifugal fan or high-pressure axial-flow with no need to install large amounts of the noise blanking facilities