It has election and purification functions. 1. The dust filtration is designed for Expressway joint gravel screening units with large flow, high concentration (Dust Volume is more than 1000g/m) and irregular dust emission characteristics of working conditions; 2.It meets the requirements of Two and Three class areas under GB16297-1996; 3.The filter has the advantages of high efficiency dust removal, small amount of maintenances, long service life, elegant appearance, etc; 4.It has election and purification functions; 5.It can be widely used in the many fields of mining operations, electric furnace melting, and machinery manufacturing, chemical products, building materials, cement (cement grinding mill), waste incineration and grain processing, etc.