A draught fan
assembly comprises a draught fan cover body and a draught fan body located in the draught fan cover body, the draught fan cover body comprises a draught fan upper cover and a draught fan lower cover which are detachably connected up and down, the draught fan upper cover is provided with a first end and a second end which are opposite to each other, and a
noise reduction mechanism is arranged in the first end; the
noise reduction mechanism comprises a horizontally-arranged air inlet rotary blade set, the flow guide direction of blades in the air inlet rotary blade set is consistent with the
airflow direction when an
impeller of the fan body rotates, the second end can stretch into a fan lower cover, and a gap is reserved between at least part of the outer wall of the second end and the inner wall of the fan lower cover. And gas entering the fan cover body from the dust inlet can flow into the
base station body from the space, and is discharged out of the
base station body through an
airflow channel which is formed between the inner wall of the
base station body and the outer wall of the fan lower cover and is communicated with the base
station exhaust hole.
Noise generated by the
fan in the dust collection process can be reduced, and the
noise reduction effect is improved.