Flue dust enter the ash bucket, thick particles directly into the ash bucket, flue dust filtered by the filter bag, dust is retained in the bag surface, purified flue gas enter clean gas chamber, through the fan discharge to the atmosphere, dusk of dust bag surface increased cause resistance rises above the setpoint, by time relay timing control deashing, or level pressure, or manual control the output signal to make pulse controller start working, turn on the pulse one by one, the compressed air jet deashing for the dust bag through spout, when compressed air eject, drive a lot of secondary air around to enter, produce a sudden expansion and vibration of the bag, the dust attached to the surface of the dust bag separate from it quickly and fall into the ash bucket, discharged by cinder valve. Jet cleaning bag by row, other bags still filter normally, the fan still run normally