Dust removal mechanism is inertia collision, screening, diffusion, and intercept action, smoke into the air velocity decreased after dust catcher, larger dust particles directly from a gravity fall into ash hopper, fine particles be trapped in filter bag filter bag surface, through the filter bag cleaning flue gas discharge. During the normal filtering by dust filter dust, actually, as the surface of the filter bag dust accumulation. Filter bag inside and outside differential pressure is gradually increased, when the pressure difference reached set value, qing fly institutions work, attached to the filter bag dust fall off, so as to achieve the purpose of ash removal.