To determine whether a paper frame primary filter needs to be replaced, a comprehensive judgment should be made based on its filtration effect, operating status and appearance. The following are the specific judgment methods and standards:
I. Judging through Resistance Changes (the most scientific method)
The core function of the paper frame primary filter is to intercept particulate matter. As the accumulation of dust increases, the resistance of air passing through the filter material will gradually rise. When the resistance reaches a certain threshold, the filtration efficiency drops and the system energy consumption increases. At this point, replacement is necessary.
Initial resistance: The resistance of a new filter (typically 5-15Pa, for specific details, please refer to the product parameter table).
Final resistance: When the resistance reaches 2 to 3 times the initial resistance (for example, the initial resistance is 10Pa and the final resistance reaches 20 to 30Pa), it indicates that the filter material is severely clogged and needs to be replaced immediately.
Operation method: Install differential pressure gauges before and after the filter, and record the resistance changes regularly. When the final resistance is reached, trigger the replacement.
Ii. Judgment through Visual Observation (Intuitive Method)
Regularly (it is recommended to do it once a week) disassemble the filter housing for visual inspection. Replacement is required when the following situations occur:
The surface of the filter material is obviously covered with dust and turned black, and even dust clumps can be seen.
The filter material is damaged, torn or has holes (possibly caused by excessive wind pressure or impact from foreign objects).
The paper frame is deformed, cracked, or the connection with the filter material is loose, causing unfiltered air to penetrate through the gaps.
Mold has appeared on the surface of the filter (mostly due to a humid environment and long-term lack of replacement).
Iii. Judging through System Operating Status (Indirect Method)
When the filter is severely clogged, it will affect the operation of the entire ventilation or air conditioning system. When the following phenomena occur, it is necessary to check whether the filter needs to be replaced:
The air volume at the air outlet has significantly decreased, and the indoor ventilation effect has declined.
The system noise has increased (as the work done by the fan to overcome resistance has increased).
The energy consumption of air conditioners or equipment rises (such as an increase in fan current);
Premature dust accumulation on the surface of downstream equipment (such as medium-efficiency filters and heat exchangers) indicates that the primary filter has failed.
Iv. Principle of Early replacement in Special Scenarios
In the following environments, it is recommended to shorten the replacement cycle even if the above standards are not met to avoid risks caused by filter failure:
High-dust environments (such as construction sites, cement plants, flour mills);
Corrosive gases or a humid environment (which may accelerate the aging of paper frames and filter materials);
Places with high requirements for air cleanliness, such as medical and food industries (which must be replaced strictly in accordance with the maintenance plan).
الملخص
To determine whether a paper frame primary filter needs to be replaced, the core criteria should be prioritized as the resistance reaching the final resistance and the filter material being damaged or severely dust-accumulated, and a comprehensive judgment should be made in combination with the system’s operating status. Timely replacement not only ensures the filtration effect but also protects subsequent equipment, reduces system energy consumption, and avoids additional costs caused by filter failure.
I. Judging through Resistance Changes (the most scientific method)
The core function of the paper frame primary filter is to intercept particulate matter. As the accumulation of dust increases, the resistance of air passing through the filter material will gradually rise. When the resistance reaches a certain threshold, the filtration efficiency drops and the system energy consumption increases. At this point, replacement is necessary.
Initial resistance: The resistance of a new filter (typically 5-15Pa, for specific details, please refer to the product parameter table).
Final resistance: When the resistance reaches 2 to 3 times the initial resistance (for example, the initial resistance is 10Pa and the final resistance reaches 20 to 30Pa), it indicates that the filter material is severely clogged and needs to be replaced immediately.
Operation method: Install differential pressure gauges before and after the filter, and record the resistance changes regularly. When the final resistance is reached, trigger the replacement.
Ii. Judgment through Visual Observation (Intuitive Method)
Regularly (it is recommended to do it once a week) disassemble the filter housing for visual inspection. Replacement is required when the following situations occur:
The surface of the filter material is obviously covered with dust and turned black, and even dust clumps can be seen.
The filter material is damaged, torn or has holes (possibly caused by excessive wind pressure or impact from foreign objects).
The paper frame is deformed, cracked, or the connection with the filter material is loose, causing unfiltered air to penetrate through the gaps.
Mold has appeared on the surface of the filter (mostly due to a humid environment and long-term lack of replacement).
Iii. Judging through System Operating Status (Indirect Method)
When the filter is severely clogged, it will affect the operation of the entire ventilation or air conditioning system. When the following phenomena occur, it is necessary to check whether the filter needs to be replaced:
The air volume at the air outlet has significantly decreased, and the indoor ventilation effect has declined.
The system noise has increased (as the work done by the fan to overcome resistance has increased).
The energy consumption of air conditioners or equipment rises (such as an increase in fan current);
Premature dust accumulation on the surface of downstream equipment (such as medium-efficiency filters and heat exchangers) indicates that the primary filter has failed.
Iv. Principle of Early replacement in Special Scenarios
In the following environments, it is recommended to shorten the replacement cycle even if the above standards are not met to avoid risks caused by filter failure:
High-dust environments (such as construction sites, cement plants, flour mills);
Corrosive gases or a humid environment (which may accelerate the aging of paper frames and filter materials);
Places with high requirements for air cleanliness, such as medical and food industries (which must be replaced strictly in accordance with the maintenance plan).
الملخص
To determine whether a paper frame primary filter needs to be replaced, the core criteria should be prioritized as the resistance reaching the final resistance and the filter material being damaged or severely dust-accumulated, and a comprehensive judgment should be made in combination with the system’s operating status. Timely replacement not only ensures the filtration effect but also protects subsequent equipment, reduces system energy consumption, and avoids additional costs caused by filter failure.
