Under the strong negative pressure of the turbine fan, when the polluted air pipe enters the air inlet, it first encounters the spoiler between the air inlet, which spoils the incoming air and slows down the flow speed. Due to the gravity settlement, the coarse dust falls directly into the dust mouth of the large particles, which plays the role of pre-dedusting. After the fine-grained and low-density dust particles enter the dust filter chamber, the dust in the air stays on the surface of the filter element, and the filtered clean air enters the air chamber and is collected by the exhaust pipe to the outlet through the fan.