Bag Filter

Bag filter (also known as bag filter) is an industrial dust removal equipment that relies on filter bags as filtering media to achieve dust and gas separation through physical interception. It has the core advantages of good dust removal effect, wide adaptability to dust types, and stable operation. It is widely used in the entire industry such as power, building materials, machinery, chemical, grain, metallurgy, etc. It can handle various types of dust containing gases with dust concentration of 50-3000g/m ³ and air volume of 200-200000m ³/h. The filtration efficiency of dust particles with a diameter of 0.3 μ m or more generally exceeds 90%. It is the core equipment for achieving dust emission standards and actual effects in the current industrial industry, and its main production environment and air quality can be subdivided into multiple specific types according to application scenarios and functional differences.

From a general structure perspective, the core components of various bag filters are consistent, including four major modules: filtration unit, ash cleaning system, airflow distribution device, ash hopper, and ash discharge component. Only the scale and detail design are adjusted according to different scene requirements. The filtering unit is the core of the equipment, with the filter bag as the key medium. The material of the filter bag needs to be carefully selected according to the working conditions: commonly used polyester fiber filter bags for processing ordinary room temperature dry dust (such as mechanical processing dust); Select PPS, aramid and other high temperature resistant (based on actual reports) filter bags for high temperature scenarios (≤ 280 ℃, such as boiler flue gas); When dealing with corrosive gases (such as chemical acid containing dust), PTFE and other performance stable filter bags are required; The filter bag is fixed on the filter bag flower plate by clamps or spring expansion rings, confirming the airtightness between the filter bag and the flower plate to prevent unfiltered gas from directly entering the clean air chamber. The dust cleaning system is the key to protecting the continuous operation of equipment. According to the dust cleaning method, it can be divided into three categories: manual vibration, online pulse spraying, and offline pulse spraying. Manual vibration has a simple structure and is suitable for low air volume and low dust concentration scenarios (such as small welding stations); Online pulse blowing does not require shutdown, and uses high-pressure gas to blow and clean dust, suitable for medium air volume continuous operation scenarios (such as grain processing lines); Offline pulse blowing is designed with compartment isolation, where a single air box is cut off from the main airflow during dust cleaning to avoid secondary dust. It is suitable for high air volume and high concentration dust scenarios (such as cement kiln dust removal). The airflow distribution device optimizes the direction of the dusty airflow through guide plates and porous distribution plates, avoiding direct erosion of the filter bag by the airflow and causing local wear. At the same time, it confirms that the airflow passes evenly through the filter bag, improving the overall filtration efficiency. Ash hoppers are often designed in a conical or square shape, with star shaped discharge valves, screw conveyors, and other ash discharge components at the bottom. Some models that handle high humidity dust also install heating or insulation devices on the outside of the ash hopper to prevent dust condensation and bridging, ensuring smooth dust discharge.