The relationship between the life of the HEPA filter and the filter element


    The HEPA filter is mainly used to capture particulate dust and various suspended solids below 0.3um. Using ultra-fine glass fiber paper as the filter material, it has the characteristics of high filtration efficiency, low resistance, and large dust holding capacity. However, because of the high price, life expectancy will be reduced if you follow it in use or improper operation. The above-mentioned situation can be avoided artificially. The following editor will share with you the impact of the HEPA filter element on life.

    1. The filtration efficiency is directly related to the high-efficiency filter element, and the service life depends on the amount of dust. The meanings are also diverse, and they are generally calculated and measured (under laboratory conditions). In practice, there are many types of dust. The life of the filter is the total weight of all dust or the total number of dust particles; the test conditions are for the amount of dust with typical particle size, sometimes the amount of all dust; The specific method indirectly reflects the concentration of light flux (colorimetric method) and fluorescence (fluorescence method); there is an instantaneous amount of a certain state, and there is also a weighted average amount of the efficiency value of the whole process of dust generation. Using different methods to test the same filter will result in different efficiency values. Without the test method, there is no way to talk about filtration efficiency.

    2. The quality of the HEPA filter element depends on the "initial resistance"; the resistance value when the corresponding filter is scrapped is called the "final resistance". Filter resistance The filter forms resistance to airflow. The filter accumulates dust and the resistance increases. When the resistance increases to a certain value, the filter is scrapped. With the same efficiency, the lower the initial resistance, the greater the ventilation of the material.

    The choice of final resistance is directly related to the service life of the filter, the range of system air volume changes, and the system energy consumption. In most cases, the final resistance is 2 to 4 times the initial resistance.

    The factors related to the increase in resistance are as follows: the dirtier the filter, the faster the resistance increases. Too high final resistance value does not mean that the service life of the filter will be significantly prolonged, but it will make the air volume of the air conditioning system drop sharply. Therefore, there is no need to set the final resistance value too high.

    3. Low-efficiency filters often use coarse fiber filter media with a diameter of ≥10m. Due to the large gaps between the fibers, excessive resistance may blow away the dust on the filter. At this time, the resistance will no longer increase, but the filtration efficiency will drop to zero. Therefore, the final resistance value of filters below G4 must be strictly limited. Each filter section should be equipped with resistance monitoring devices. The final resistance depends on the instrument to determine, not just the operator's feeling.

    More filter element materials are classified into the following categories: HEPA filters include HEPA filters with partitions and HEPA filters without partitions, and HEPA filters with partitions include: HEPA filters with partitions, high-temperature resistant HEPA filters, and High-humidity high-efficiency filter, non-partition high-efficiency filter, including combined high-efficiency filter, non-partition high-efficiency filter, liquid tank no-partition high-efficiency filter, ultra-low resistance non-partition high-efficiency filter, knife holder type No partition HEPA filter, ULPA filter 0.1um filtration efficiency.