To determine whether the filter material of an aluminum frame combined filter needs to be replaced, a comprehensive judgment should be made based on multiple indicators such as filtration effect, resistance change, and appearance condition. The specific methods are as follows:
I. Judgment through resistance monitoring (the most scientific method)
Monitor the changes in pressure difference
Install differential pressure gauges before and after the filter to record the initial resistance (the resistance after the new filter material is installed). When the operating resistance reaches 2 to 3 times the initial resistance, it indicates that the filter material is severely clogged and the filtration efficiency has dropped significantly. It needs to be replaced immediately.
For instance, the initial resistance of a new filter material is 50Pa. When the resistance rises to 100-150Pa, the replacement threshold is reached.
Abnormal fluctuation of resistance
If the resistance suddenly drops significantly (far below the initial resistance), it may be that the filter material is damaged (such as having holes or tears), allowing unfiltered air to directly penetrate. An emergency inspection and replacement of the filter material are required.
Ii. Judging by Appearance Status (Intuitive Observation Method)
Dust degree on the surface area of the filter material
If there is a large area of thick dust accumulation on the surface of the filter material (the windward side), and it still cannot be removed after conventional cleaning (such as purging and water washing), or if the dust accumulates seriously again within a short time after cleaning, it indicates that the pores of the filter material have been deeply blocked and it needs to be replaced.
For transparent or light-colored filter materials, if they are visibly black or yellow (due to the adhesion of oil stains, cooking fumes or chemical pollutants) and cleaning is ineffective, they need to be replaced.
Physical damage to the filter material
Check whether the filter material has any tears, holes, edge peeling or other conditions. Even if the damaged area is small, it will lead to filter failure (unfiltered air leaks from the damaged area), and it must be replaced.
If the filter material hardens or becomes brittle (such as paper filter material becoming brittle after getting damp, or synthetic fiber filter material aging due to long-term high temperature), losing its original elasticity and filtration structure, it also needs to be replaced.
Iii. Judging through Operational Effects (Indirect Feedback Method)
The air quality downstream has declined
If the dust concentration in the downstream area of the filter (such as workshops or clean rooms) increases significantly, or if there is an unpleasant odor or the visibility of particulate matter increases, and after excluding other pollution sources, it is very likely that the filtration efficiency of the filter material is insufficient and it needs to be replaced.
The system is operating abnormally
The air volume of the ventilation system has significantly decreased (due to excessive air resistance caused by clogged filter materials), affecting the normal operation of the equipment.
The operating noise of the system increases (as turbulence intensifies when the airflow passes through the clogged filter material). At this point, the condition of the filter material needs to be checked and replaced if necessary.
Iv. Judgment Based on Usage Time and Environment (Supplementary Reference)
For ordinary environments (such as offices and shopping malls) : It is recommended that the filter material be used for 3 to 6 months. Even if the appearance and resistance do not reach the threshold, it should be replaced regularly (to avoid microbial growth or filter material aging).
In highly polluted environments (such as cement plants and woodworking workshops), the filter material may need to be replaced every 1 to 2 months, which should be determined based on the actual dust accumulation rate.
Special environments (such as damp environments) : If the filter material shows signs of mold or an unpleasant odor, it should be replaced immediately even if it has been used for a short period of time (to avoid secondary pollution).
Resumen
The core logic for determining whether the filter material should be replaced is: excessive resistance, physical damage, ineffective cleaning, and reduced performance. Among them, resistance monitoring is the most accurate basis, while appearance and operational performance can be used as auxiliary judgment methods. In actual operation, it is recommended to prioritize the data from the differential pressure gauge and combine it with regular visual inspections to ensure the efficient operation of the filtration system.
I. Judgment through resistance monitoring (the most scientific method)
Monitor the changes in pressure difference
Install differential pressure gauges before and after the filter to record the initial resistance (the resistance after the new filter material is installed). When the operating resistance reaches 2 to 3 times the initial resistance, it indicates that the filter material is severely clogged and the filtration efficiency has dropped significantly. It needs to be replaced immediately.
For instance, the initial resistance of a new filter material is 50Pa. When the resistance rises to 100-150Pa, the replacement threshold is reached.
Abnormal fluctuation of resistance
If the resistance suddenly drops significantly (far below the initial resistance), it may be that the filter material is damaged (such as having holes or tears), allowing unfiltered air to directly penetrate. An emergency inspection and replacement of the filter material are required.
Ii. Judging by Appearance Status (Intuitive Observation Method)
Dust degree on the surface area of the filter material
If there is a large area of thick dust accumulation on the surface of the filter material (the windward side), and it still cannot be removed after conventional cleaning (such as purging and water washing), or if the dust accumulates seriously again within a short time after cleaning, it indicates that the pores of the filter material have been deeply blocked and it needs to be replaced.
For transparent or light-colored filter materials, if they are visibly black or yellow (due to the adhesion of oil stains, cooking fumes or chemical pollutants) and cleaning is ineffective, they need to be replaced.
Physical damage to the filter material
Check whether the filter material has any tears, holes, edge peeling or other conditions. Even if the damaged area is small, it will lead to filter failure (unfiltered air leaks from the damaged area), and it must be replaced.
If the filter material hardens or becomes brittle (such as paper filter material becoming brittle after getting damp, or synthetic fiber filter material aging due to long-term high temperature), losing its original elasticity and filtration structure, it also needs to be replaced.
Iii. Judging through Operational Effects (Indirect Feedback Method)
The air quality downstream has declined
If the dust concentration in the downstream area of the filter (such as workshops or clean rooms) increases significantly, or if there is an unpleasant odor or the visibility of particulate matter increases, and after excluding other pollution sources, it is very likely that the filtration efficiency of the filter material is insufficient and it needs to be replaced.
The system is operating abnormally
The air volume of the ventilation system has significantly decreased (due to excessive air resistance caused by clogged filter materials), affecting the normal operation of the equipment.
The operating noise of the system increases (as turbulence intensifies when the airflow passes through the clogged filter material). At this point, the condition of the filter material needs to be checked and replaced if necessary.
Iv. Judgment Based on Usage Time and Environment (Supplementary Reference)
For ordinary environments (such as offices and shopping malls) : It is recommended that the filter material be used for 3 to 6 months. Even if the appearance and resistance do not reach the threshold, it should be replaced regularly (to avoid microbial growth or filter material aging).
In highly polluted environments (such as cement plants and woodworking workshops), the filter material may need to be replaced every 1 to 2 months, which should be determined based on the actual dust accumulation rate.
Special environments (such as damp environments) : If the filter material shows signs of mold or an unpleasant odor, it should be replaced immediately even if it has been used for a short period of time (to avoid secondary pollution).
Resumen
The core logic for determining whether the filter material should be replaced is: excessive resistance, physical damage, ineffective cleaning, and reduced performance. Among them, resistance monitoring is the most accurate basis, while appearance and operational performance can be used as auxiliary judgment methods. In actual operation, it is recommended to prioritize the data from the differential pressure gauge and combine it with regular visual inspections to ensure the efficient operation of the filtration system.
