Will the air volume be affected when the FFU filter level is increased?
Level improvement is not just a change in efficiency
In clean room projects, it is sometimes necessary to increase the efficiency rating of FFU filters. For example, increase it from H13 to H14, or increase it from H14 to U15. Some projects believe that as long as the filter size is the same, it can be replaced directly.
However, when the filter level is increased, the air volume may be affected. An increase in efficiency rating usually means an increase in filter media density, a change in pleated structure, or an adjustment in filter media area. These changes affect the filter's resistance characteristics. When the resistance increases, the working point of the FFU fan will move and the actual air volume may decrease.
Therefore, improving the filter level cannot only focus on efficiency, but also requires rechecking the air volume and static pressure. Aili Industrial has complete production capabilities in FFU complete machines and high-efficiency filters, and can cooperate with the project to check the matching of filters and complete machines. For the basic structure of the FFU machine, please refer toAili Industrial FFU fan filter unit。
How filter resistance changes
Filter resistance is related to the filter material, folding structure, filter material area and air volume. As the efficiency level increases, the filter material may be denser and resistance generally increases.
The magnitude of the resistance change depends on the specific product and structure. Some high-efficiency filters balance resistance by increasing the area of filter material so that the resistance does not rise significantly. Some filters are subject to size restrictions and resistance may increase significantly.
When selecting, you should confirm the actual resistance of the filter at the target air volume, rather than just looking at the efficiency level.
How to move the FFU working point
The actual operating point of the FFU is determined by the fan curve and the system resistance curve. As filter resistance increases, the system resistance curve shifts upward. If the FFU adopts constant speed control, the working point moves to the direction of low air volume and the air volume decreases. If constant air volume control is used, the fan will increase the speed to maintain the air volume, but the power may increase.
Therefore, after increasing the filtering level, the FFU working point needs to be rechecked. For details, please refer toHow to read the FFU fan curve and how to determine the operating point.
How to check the fan static pressure margin
If the filter resistance increases, the FFU fan needs to provide higher static pressure to maintain the target air volume. If the fan static pressure margin is insufficient, the air volume may not meet the requirements.
The verification includes: filter resistance at the target air volume; static pressure capacity of the FFU fan under this resistance; static pressure margin of the fan; and changes in the working point of the filter after dust accumulation.
If the static pressure margin is insufficient, you may need to choose an FFU with a larger fan capacity, or choose a filter with lower resistance.
How to deal with a drop in air volume
If the air volume decreases after increasing the filtration level, you can consider the following methods: select a filter model with lower resistance; increase the filter material area; adjust the FFU speed or control settings; replace the FFU with a larger fan capacity.
The treatment method should be determined based on project requirements and equipment conditions. If the project has strict requirements on air volume, it can be checked clearly during the selection stage to avoid adjustments after operation.
How does control affect
When FFU adopts constant speed control, the air volume will decrease as the filter resistance increases. When FFU adopts constant air volume control, the fan will automatically adjust the speed to maintain the air volume, but the power may increase and the fan working range needs to be sufficient.
If the project requires stable air volume, constant air volume control can be considered. For details, please refer toFFU requires constant air volume control or constant speed to understand the control method selection.
Aili industrial filter matches the whole machine
Aili Industry has complete production capabilities in FFU complete machines and high-efficiency filters, and can provide filter and complete machine matching solutions according to project filtration level requirements. The filters include different efficiency levels from H13 to U17, and the entire machine can adjust the fan configuration according to changes in resistance.
If the project requires ULPA filter, you can refer toFFU is equipped with ULPA ultra-high efficiency filter to understand the interface and configuration.
Issues that should be confirmed in advance during project communication
During the filter level improvement stage, it is recommended to confirm the following with the FFU manufacturer: target filtration level; filter resistance and filter material structure; FFU fan static pressure margin; operating point at target air volume; control method; change in air volume after dust accumulation on the filter; whether the fan configuration needs to be adjusted; verification method.
If you are considering increasing the FFU filter level, you can visitAili Industrial FFU fan filter unit to learn about the complete machine configuration, you can also refer toLearn about HEPA and ULPA filters with different efficiency levels, or contact Aili Industrial for matching support.
in conclusion
After the filter level is increased, the density and structural changes of the filter material may increase the resistance and affect the FFU operating point and air volume. To improve the filtration level, you can't just look at efficiency, but also need to recheck the fan static pressure and air volume. Resistance changes, working point movement, static pressure margin and control methods are the main links for verification.
Aili Industrial has complete production capabilities in FFU complete machines and high-efficiency filters, and can cooperate with the project to check the matching of filters and complete machines. If you need to know more about FFU filter selection, you can visitAili Industrial FFU fan filter unit , you are also welcome to contact Aili Industrial for project support.
