How to determine whether the ultra-low resistance high-efficiency filter unit needs cleaning

To determine whether the ultra-low resistance high-efficiency filter unit needs cleaning, it can be considered from the following aspects:
Resistance change
Observe the differential pressure meter: If the filter unit is installed with a differential pressure meter when the differential pressure reaches or exceeds 1.5-2 times the initial resistance, it usually means that the filter unit has accumulated more dust, the resistance is increased, and it needs to be cleaned. For example, the initial resistance is 200Pa, and when the pressure difference reaches 300-400Pa, cleaning can be considered.
Compare fan operation parameters: In the case of constant fan frequency, if it is found that the air volume is significantly reduced, or the current and power of the fan are increased, it may be caused by the increased resistance of the filter unit, at this time, check whether the filter unit needs to be cleaned.
Visual inspection
View the filter material surface: directly observe the filter material surface of the filter unit, if there is obvious dust accumulation, or discoloration, especially in the fold of the filter material, the edge, and other parts, indicating that the filter unit has absorbed a lot of dust, need to be cleaned.
Check the border and seal: Check whether there are traces of dust leakage at the border and seal, if there are, it may be that the sealing performance of the filter unit has decreased, or the internal filter material has been saturated, and can not effectively block the dust, need to be cleaned or checked and repaired.
Running time: According to the use of the filter unit environment and running time to determine. Generally, in a cleaner environment, such as the electronic chip production workshop, you can check whether it needs cleaning every 3-6 months according to experience; In dusty environments, such as cement plants, mines, etc., it may be necessary to check every 1-3 months.
Air quality testing: Through professional air quality testing equipment, detect the filtered air particle concentration, microbial content, and other indicators. If it is found that the air quality is not up to standard, and after excluding other factors, it is likely that the filtration effect of the filtration unit is reduced, and it needs to be cleaned or replaced.
System performance decline: If the entire ventilation or air conditioning system appears cooling, heating effect is not good, or indoor odor, dust increase, etc., after eliminating another equipment failure, should consider whether the filter unit needs to be cleaned due to blockage, to restore the normal performance of the system.