How to check if the local air volume of ULPA is low? Static plenum and air supply distribution

of the ULPA filter is low and should be investigated layer by layer based on measurement, upstream distribution, filter element status and downstream obstruction. The local air volume If the total air volume or central wind speed is normal, local insufficient protection cannot be ruled out. The concealment of low local air volume is that the total air volume of the system may be fully up to standard, and the central air speed may also appear to be normal. Only the actual air supply in a certain area is insufficient—and this area may happen to be a sensitive workstation. When troubleshooting this type of problem, the representativeness of measuring points is more important than the number of measuring points. Aili Industry isFFU fan filter unit andIn the box structure design of the fan filter unit at the EFU equipment end , the static pressure box space and internal air flow path are determined as structural elements.The FFU computer group control system records the air volume and operating status of the partitions. When the local air volume is abnormal, the data of the corresponding partition can be retrieved and compared with the structural layout for investigation.

1. Use consistent measuring points to confirm abnormalities: unify the measuring caliber first

Check the instrument, distance and operating status, and record the boundary of the low-speed area to avoid personnel position or probe deviation from affecting the conclusion.

The first step in local low air volume is to confirm that the anomaly actually exists. At different measurement distances, different probe angles, and different personnel positions, the measured wind speed may be significantly different. When confirming, the measurement plane, measurement distance and probe orientation should be fixed, the data of each point should be recorded according to the grid, and the boundaries of the low-speed area should be marked. Aili Industry isThe HEPA/ULPA filter matching solution provides structural instructions according to the measurement plane used in the project.the FFU fan filter unit is recorded in a multi-point arrangement, and the locations of the measuring points correspond to the structure, which facilitates comparison during on-site measurements. The factory test of The relationship between grade and air supply requirements can be referred toISO cleanliness level comparison。

2. Compare resistance and wind distribution: upstream inlet, static pressure box and internal obstacles

Check the inlet, static pressure space, internal obstacles and filter element for local moisture or dust accumulation, and determine whether there is bias flow based on the readings in adjacent areas.

The cause of localized low speeds is usually upstream. The offset position of the inlet will cause the airflow to concentrate on one side. Insufficient static pressure space will prevent the airflow from spreading. Internal obstacles or cables will change the direction of the local airflow. Local moisture or dust accumulation in the filter element will increase the resistance in the area and decrease the air volume. Aili Industry isIn the box design of the fan filter unit at the EFU equipment end, the internal structure is arranged according to the inlet position and static pressure space.Compact models such as ultra-thin EFU balance structural size and distribution conditions in a limited space.The FFU fan filter unit complete machine test records the pressure drop at the inlet, box and filter element in sections to facilitate the determination of local low-speed resistance sources. The relationship between static pressure box and distribution can be referred toHEPA FAQs and Selection Guide。

3. Distinguish between filter element problems and air distribution problems: whether it will recover after replacing the filter element in the same area

If the local low speed disappears after replacing the filter element, it means that the cause is the filter element; if the low speed still exists after the replacement, it means that the cause is in the box structure or the upstream air distribution.

This comparison method is a direct means of distinguishing the source of the problem. Aili Industry isWhen the ULPA ultra-high efficiency filter is delivered, the test data of a single filter element can be traced according to the serial number.Non-standard ULPA filter projects can provide replacement parts of the same specification for comparison testing.Tank seal ULPA filter andThe structural differences of the partition-less ULPA ultra-high-efficiency filter can also be used as a reference when replacing and comparing. Please refer to the method of distinguishing filter element and air distributionULPA ultra-high efficiency filter FAQ and selection guide。

4. Verify the complete distribution after rectification: you cannot only measure the original low-speed points

After adjusting the flow equalization, clearing obstacles or solving filter problems, re-measure the average value and each point, and observe the flow pattern in the process area if necessary. Measuring only the recovery of the original low-speed point does not mean that the distribution of the entire air supply surface has been improved - the adjustment may have moved the low-speed area to another location.

Aili Industry isFFU fan filter unit andIn the rectification project of the fan filter unit at the EFU equipment end , the entire air supply surface was re-measured according to the original measurement plane and grid.The FFU computer group control system records the partition air volume data before and after rectification for easy comparison. For verification after device side rectification, please refer toEFU FAQ and technical support。

5. Related questions and answers

Is the local low speed necessarily caused by the filter element being clogged?
It may also come from upstream bias flow, downstream obstacles or measurement conditions, which should be investigated separately.

The total air volume reaches the standard, but the local wind speed is low. Is this normal?
Not normal. The total air volume reflects the total volume, and the local wind speed reflects the distribution. If the total volume reaches the standard, it cannot rule out insufficient local protection.

Is it okay to only measure the original low-speed points after rectification?
Not recommended. The entire air supply surface should be retested to confirm that the low speed zone has not moved to other locations.

6. Related articles

ULPA ultra-high efficiency filter FAQ and selection guide

Ultra-thin EFU

No partition ULPA ultra high efficiency filter

HEPA FAQs and Selection Guide

7. Key points for selection and acceptance inspection

8. Product matching and technical support from Aili Industrial

Aili Industry isFFU fan filter unit andIn the box structure design of the fan filter unit at the EFU equipment end , the static pressure box space and internal air flow path are determined as structural elements.The FFU computer group control system records the air volume and operating status of the partitions. When the local air volume is abnormal, the corresponding partition data can be retrieved and compared with the structural layout.The HEPA/ULPA filter matching solution provides structural instructions according to the measurement plane.The FFU fan filter unit was tested at multiple points to record the distribution and record the pressure drop in sections.The internal structure of the fan filter unit at the EFU equipment end is arranged according to the inlet position and static pressure space.Ultra-thin EFU balances size and distribution conditions in a limited space.ULPA ultra-high efficiency filter can trace the detection data of a single unit according to the serial number.Non-standard ULPA filters can provide replacement parts of the same specification for comparison testing.Tank seal ULPA filter andThe structural differences of the partition-less ULPA ultra-high-efficiency filter can be used as a reference for replacement comparison. Provide process objectives, installation drawings, operating conditions and acceptance requirements, and can further communicate ULPA standard specifications, non-standard interfaces, samples and batch matching. The specific parameters and test range are based on the confirmed model and technical documents.