When the cleanliness is not up to standard, how to locate the FFU seal or the airflow organization problem first?
Substandard cleanliness is not necessarily a problem with the FFU itself.
During clean room testing, if it is found that the particle concentration does not meet the standard, FFU will often be suspected at the scene. Some projects will directly replace the filter, or increase the FFU speed. However, the reasons for substandard cleanliness may come from many aspects. FFU sealing and air flow organization are two common but different reasons.
Sealing problems refer to unfiltered air bypassing the filter or box interface and entering the clean area, usually manifested by high local particle counts. The problem of airflow organization means that the clean airflow does not effectively cover key areas, or the return air path is not smooth, resulting in the accumulation of particles. The two may behave similarly, but process in different directions.
Therefore, when the cleanliness does not meet the standard, you should first distinguish the type of problem through testing and observation, and then decide how to deal with it. Aili Industrial has complete production capabilities in FFU complete machines and clean engineering supporting equipment, and can cooperate with the project to analyze sealing and air flow issues. For the basic structure of the FFU machine, you can refer toAili Industrial FFU fan filter unit。
First look at whether the pollution distribution is local or overall
Contamination distribution is the first step in investigation. If excessive particles are concentrated under a certain FFU, near a sealing interface, or in a local area, sealing problems are more likely. If the excessive particles are widely distributed or appear in multiple areas, airflow organization problems are more likely.
Local contamination may also appear at the FFU splicing boundary, around the lamp, near the return air outlet, or at the edge of the structure. Contamination in these locations may be related to areas of weak airflow and not necessarily seal leaks.
The overall contamination may be related to insufficient air exchange in the room, insufficient number of FFU, poor return air, or personnel activities. During the investigation, the location, concentration and occurrence time of the pollution should be recorded and compared with the FFU layout diagram and airflow organization diagram.
What are the symptoms of sealing problems?
The manifestations of sealing problems are often localized. Near the FFU air outlet surface, filter frame, sealing strip or box joints, the particle concentration may be significantly higher than the surrounding area. If the sealing interface is scanned for leakage, local leakage points may be found.
Sealing problems may come from improper installation of the filter, aging or deformation of the sealing strip, uneven pressing mechanism, unsealed box joints, or insufficient sealing liquid level in the liquid tank. These issues have nothing to do with the quality of the filter itself, but rather with installation and maintenance.
If the filter passes the factory leak test, it does not mean that the seal is intact after installation. Installation of seals requires individual inspection. For specific methods, please refer toIf the FFU filter element passes the leak test, why should the installation seal be checked? (Note: This link is an example of a detachable FFU page. For actual seal inspection content, please refer to the corresponding page on the site).
What are the symptoms of airflow organization problems?
Manifestations of airflow organization problems are often related to regional airflow conditions. If the wind speed above key workstations is low, or the airflow direction deviates, the clean airflow may not be able to effectively cover the product. If the return air path is blocked by equipment or materials, airflow stagnation may occur in local areas.
Airflow organization problems may also manifest as: the wind speed on the FFU outlet surface is normal, but the wind speed at the process location is low; the average cleanliness of the room is acceptable, but some workstations exceed the standard; particles rise significantly when personnel operate; equipment heating or exhaust changes affect the airflow direction.
To troubleshoot airflow organization problems, it is necessary to measure wind speed and airflow direction at key locations, rather than just measuring the FFU outlet surface. Measuring points should cover product exposure locations, personnel operating locations and return air paths.
How to independently test seals and airflow
To distinguish between sealing and airflow problems, independent testing can be done separately. Seal detection usually uses the scanning leak detection method, scanning near the filter frame, sealing strip and box joints to confirm whether there is any local leakage. Airflow detection typically uses wind speed measurement and airflow visualization to confirm airflow coverage and direction at critical locations.
If problems are found in the sealing test, the sealing can be dealt with first, and then the cleanliness can be retested. If the sealing test is normal but the cleanliness is still not up to standard, you can further check the airflow organization. The two tests should be recorded separately to avoid confusion.
How to adjust and retest
If it is confirmed that there is a sealing problem, the treatment methods include reinstalling the filter, replacing the sealing strip, adjusting the pressing mechanism or repairing the box seams. Leak detection should be performed again after treatment to confirm the sealing effect.
If it is confirmed that it is an airflow organization problem, the treatment methods include adjusting the FFU position or rotation speed, optimizing the return air path, increasing local air supply, or adjusting the enclosure structure. After treatment, wind speed and cleanliness should be re-measured at key locations.
After adjustment, it is recommended to keep records, including problem description, detection methods, treatment measures and retest results. For batch projects, if there is a problem with a certain FFU, you can check whether other equipment in the same batch has similar problems.
Issues that should be confirmed in advance during project communication
During the cleanliness non-compliance investigation stage, it is recommended to confirm the following with the FFU manufacturer and testing party: contamination distribution and location; detection methods and instruments; seal detection methods and judgment standards; air flow measurement locations and methods; FFU operating status and speed; return air path and pressure difference status; treatment measures and re-testing methods; whether on-site support from the manufacturer is required.
If you are dealing with substandard cleanliness issues, you can visitAili Industrial FFU fan filter unit to learn about the complete machine configuration, you can also refer toFFU is equipped with ULPA ultra-high efficiency filter to learn about the filter installation interface, or contact Aili Industrial for troubleshooting support.
in conclusion
When the cleanliness is not up to standard, you should first distinguish between FFU sealing problems and airflow organization problems. Sealing problems usually manifest as localized leaks, and airflow organization problems often manifest as insufficient regional airflow coverage. Contamination distribution, seal detection and air flow detection can help locate problems. After treatment, retest to confirm the effect.
Aili Industrial has complete production capabilities in FFU complete machines and clean engineering supporting equipment, and can cooperate with the project to analyze sealing and air flow issues. If you need to know more about cleanliness inspection methods, you can visitAili Industrial FFU fan filter unit , you are also welcome to contact Aili Industrial for project support.
