In clean air conditioning systems, bag-type filters are commonly available in three series: M, F, and H. Filters of different grades have significant differences in their filtration efficiency, dust holding capacity, and operating resistance. Therefore, they need to be selected and matched according to the three-level filtration system of primary, intermediate, and high efficiency. The M-grade filter (M5/M6) is used as the front-end pre-filter and is installed at the very front of the air conditioning unit, intercepting large particles of dust and protecting the subsequent medium-efficiency filters. When installing the bag-type M filter, orient the bag-type filter bag in the direction of the airflow, fix it on the filter frame, check that the bag body is not stuck or damaged, lock the frame pressure block, and ensure the sealing of the frame. During replacement, shut down the machine to relieve pressure, loosen the frame fasteners, remove the old filter bag, clean the accumulated dust on the frame, and install the new bag-type filter.
The F-class filters (F7/F8) are medium-high efficiency filters. They are usually placed at the rear end of the M-class filters and serve as a protective barrier for the H-class high-efficiency filters, intercepting fine particles and reducing the dust load on the rear-end high-efficiency filters, thereby extending the service life of the high-efficiency filters. The common specifications for F-class bag filters are 6P and 8F. The filter bags are made of chemical fiber melt-blown material, which is anti-static and does not easily shed fibers.
The H-class bag filter (H13) is a highly efficient bag filter, mainly used for end-of-line filtration in certain working conditions. The filter material is made of glass fiber, and it has a high filtration efficiency for sub-micron particles. The number of bags determines the filtration area. The more bags there are, the larger the filtration area becomes, the lower the initial resistance is, and the higher the dust holding capacity is. For example, the 8F bag filter can control the initial resistance within a lower range under the rated air volume.
