方法一：真空吸污法

Method 1: vacuum suction method

是使用真空吸污管，然后人工来进行清除。它要求风管有较大的检修孔，但在人工操作时可能会有遗漏的地方，因此不是非常好。

The vacuum suction pipe is used and then manually removed. It requires larger manholes, but there may be omissions in manual operation, so it is not very good.

方法二：动力洗刷法

Method two: power washing method

是使用气动或者电动毛刷将脏污清除掉，然后将脏污集中到一起，可以使用真空收集器来进行收集，但它要求不能破坏风管的表层。

Remove the dirt with pneumatic or electric brush, and then collect the dirt together. You can use a vacuum collector to collect it, but it requires no damage to the surface of the pipe.

方法三：气体冲洗法

Method three: gas washing method

通过软管来输送压缩空气，以便驱除脏污，而脏污会被输送到真空容器中集中起来。

The compressed air is conveyed by hoses to remove dirt, and dirt is sent into the vacuum vessel to concentrate.