In maintenance, the paper filter element must not be put in the oil cleaning, otherwise the paper filter element will fail, but also easy to cause flying accidents. Maintenance, can only use vibration method, soft brush division (along with its wrinkled brush) or compressed air back blowing method to remove dust and dirt attached to the surface of the paper filter element. For the coarse filter part, dust should be removed from the dust collecting part, blade and cyclone pipe in time. Even if each time can be carefully maintained, the paper filter element can not completely restore the original performance, its intake resistance will increase, therefore, generally when the paper filter element needs to be maintained for the fourth time, it should be replaced with a new filter element. If the paper filter element is cracked, perforated or the filter paper and the end cover are degummed, it should be replaced immediately.