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How to tell if a high efficiency filter is obsolete
How to tell if a high efficiency filter is obsoleteThere are two situations in which a high-efficiency filter can be judged to be obsolete:1. When doing environmental testing, it is found that the suspended particles in the room are high, and after solving other reasons, the dispersion plate of the high-efficiency air supply outlet is removed, and the surface of the air supply outlet is damaged, with black ash stains, in this phenomenon the high-efficiency filter cannot be used, and the new filter is replaced in time. If the filter is not broken, use the air volume cover to cover the room air supply outlet to measure the air supply volume of each air supply outlet, the air supply volume becomes large, for replacement. 2. If there is no difference in other air filters, but the air supply volume of the room air outlet is less than half of the standard air supply volume, it means that the filter has been blocked, and the blocked high-efficiency filter should be replaced. Efficient filter replacement: remove the scattered flow plate of the scrapped efficient filter; loosen the fixed parts of the efficient filter, after removing the efficient filter, check the static pressure box, fixed parts, and panel for rust and loss, find rust and corrosion, need to remove rust and spray paint treatment. According to the specifications and quantity of the new high-efficiency filter, check the outer packaging of the high-efficiency filter should be complete, with no damage, the certificate of conformity of the high-efficiency filter should be complete, the outer frame should be firm and durable, and the filter paper should not be damaged; after removing the outer packaging, put it in a clean and dry place, and the inner packaging should be kept intact before installation. When replacing the high-efficiency filter in the clean area, clean the static pressure box of the high-efficiency filter with a clean rag, then open the inner packaging of the high-efficiency filter, paste the sealing strip to the inlet side of the high-efficiency filter, smoothly put the high-efficiency filter into the static pressure box, pay attention to light handling, and record the specification model, number and installation position of the high-efficiency filter. When fixing the filter, first check that the filter is in the middle of the static pressure box, and the distance between the filter and the static pressure box is comparable, and the fixing piece should be fixed at the corner to prevent uneven force or damage to the filter. The fixing nuts in the static pressure box should be tightened so that the connection between the high-efficiency filter and the static pressure box fits and is sealed. Then turn on the air conditioning unit, ventilate the system, open the inner packaging of the high-efficiency filter, and replace it according to the above steps. Once the HEPA filter is installed, run the system and check for air leaks. When air leaks are detected, the following is done: fasten the fixings or replace the seals and reinstall them, or replace the HEPA filter with a new one if the HEPA filter itself is leaking. Next, install the HEPA filter panel. When installing the panel, install it in the original marked direction, and reduce the gap at the connection between the panel and the roof to prevent dust accumulation. After installation of the HEPA filter, environmental testing should be carried out again and verification is done to provide a very reliable basis for the next determination of HEPA filter scrapping. Introduction of the surface speed, dust capacity, and life of the HEPA filter Surface speed and filtration speed: The ability of the HEPA filter to handle air volume is usually expressed in terms of surface speed, sometimes also in terms of filtration speed, which is the same for flat filters. Face velocity is the speed of airflow through the filter section, generally expressed in m/s. The filtration speed is the air velocity over the area of the filter media. Due to the different requirements of high-efficiency filters, the area of the filter media set up in the filter varies, sometimes being tens of times larger than the filter cross-sectional area. Therefore, the filtration speed is smaller than the surface speed, usually expressed in m/min or cm/s. The size of the filtration speed is directly related to the performance of the filter. Too high a filtration speed will reduce the purification efficiency and increase the resistance; therefore, to reduce the resistance, the filtration speed of high-efficiency filters is usually small, while the area of the filter material is large. Dust capacity and life The dust capacity of an air filter is the rated amount of dust that can be contained and retained when the filter changes from initial resistance to final resistance, expressed as kg of dust per meter of the transition area. For high-efficiency filters, the dust capacity has a more important significance than the general industrial dust collector (e.g. bag filter), because when the dust collector reaches the rated dust capacity, the dust adhering to the dust collector filter media often falls into the dust hopper through dust cleaning, and the resistance drops and reverts to a state close to the original. This is not the case for air filters, which need to be taken down and cleaned, and regenerated (e.g. by soaking the filter) after reaching their rated capacity, sometimes by replacing the filter media. The size of the dust capacity therefore also determines the life of the filter. The larger the dust capacity, the longer the life of the filter, so it can be seen that the dust capacity is an important performance indicator of the life of the air filter. The amount of dust holding capacity is related to the high-efficiency filter material. The ideal structure of the filter material is a gradient structure, i.e. the structure of the filter material transitions from loose to dense, this structure can obtain both a large dust-holding capacity and high efficiency. |
