Dust Control Handbook for Industrial Minerals Mining and Processing

Figure 1.20. Cartridge collector with dust filter canisters.Cartridge collectors are the latest generation of fabric collector. Unlike other fabric collectors inwhich the filtering media are woven or felt bags, this type of collector employs cartridges thatcontain a pleated filtering media. The pleated cartridges can be made from a variety of mediaincluding polyester or synthetic material. Due to the pleated design, the total filtering surfacearea is greater than with conventional bags of the same diameter. However, the pleated designcartridges produce very high approach velocities and thus greater re-entrainment onto thecartridge can occur. Filtration velocities are therefore limited to air to cloth ratios of less than2:1.The cartridge filter works like the pulse jet baghouse collector in that dust is filtered on theoutside of the elements. Cleaning air (compressed) is blown into the center of the elements,discharging the excess collected material. Cartridge collectors involve lower capital costs than abaghouse because the cartridges have more area than bags, therefore fewer are required.Cartridge collectors have lower headroom requirements, because the cartridges are inserted fromthe side of the unit as opposed to the top. Cartridges are shorter than bags, and there are fewer ofthem. Media can also be changed rapidly, facilitating a higher level of maintenance. Limitationsto cartridge collectors include a lack of flexibility based on extreme temperature and moistureapplications, since there are not as many varieties of filter fabrics available as there are forbaghouses. Because of the high filter area per unit and the pleated design, media replacementcosts are high on a per-cartridge basis.The main advantages of cartridge collectors are the compact design and ease of cartridgechanging, resulting in reduced dust exposure to workers. New cartridges are packaged in acardboard box, and to change cartridges the worker simply removes the new cartridge from thebox, extracts the used cartridge and places it in the box, then installs the new cartridge, withminimal dust exposure to the worker. Within the collector, the cartridges are cleaned by aconventional pulse jet cleaning system. In practice, the cartridges can have a two-year life inabrasive applications. However, purchasing this type of collector may require the user topurchase cartridges from the equipment supplier, reducing a competitive pricing advantage.Fundamentals of Dust Collection Systems 39