Turbofan with double-impeller noise reduction structure

The invention relates to the technical field of breathing machine accessories, in particular to a turbofan with a double-impeller noise reduction structure. The turbofan comprises a centrifugal fan main body and an outer rotating cylinder axially and fixedly installed on a rotating shaft at the upper end of the centrifugal fan main body. According to the turbofan with the double-impeller noise reduction structure, a lateral assembling frame internally provided with internal adjustable blades is fixedly connected to the arc-shaped surface of the outer side of the outer rotating cylinder, the wind direction of the centrifugal fan is adjusted by adjusting the angles of the internal adjustable blades, and therefore, the application range of the turbofan is wider; a detachable elastic extrusionlimiting device is arranged on the inner side of the outer rotating cylinder to conduct elastic extrusion limiting on the internal adjustable blades, people can conveniently disassemble and replace the internal adjustable bl