How to set the EFU air outlet speed? Air supply area, cleanliness target and uniformity confirmation method

Direct answer: The setting of the EFU outlet wind speed should be carried out in the order of 'clean target → air supply area → target wind speed → air volume reverse estimation → uniformity confirmation'. The cleanliness target determines the required wind speed range, and the air supply area determines the air volume demand. After the target wind speed is determined based on the two, the required air volume and fan operating point of the EFU are deduced. Finally, the measurement point arrangement is used to confirm whether the wind speed distribution on the air outlet surface is uniform. The wind speed setting is not a single value, but needs to be comprehensively confirmed based on the equipment structure, filter resistance and actual working conditions.

The EFU air outlet speed directly affects the air supply coverage effect of the clean area. Setting it too high will increase energy consumption and noise, and setting it too low may not meet the cleaning requirements. The following will start from three aspects: air supply area, cleaning target and uniformity.

1. The cleanliness target determines the wind speed range

The clean target is the starting point for setting the outlet air speed. Different cleanliness levels and process requirements have different wind speed ranges:

After the cleanliness target is determined, it can be judged in what range the wind speed should be set. If you only set it based on experience values, it may not match the actual cleaning needs.

2. The air supply area determines the air volume demand

The air supply area is a key parameter in wind speed setting. Need to confirm:

1. Effective air supply area : based on the actual air outlet area of ​​the filter, excluding the area occupied by the frame and sealing strip;

2. Structural obstruction : The part of the air outlet surface that is blocked by brackets, cables or equipment structures needs to be evaluated whether to be included;

3. Multi-filter configuration : When multiple filters are connected in parallel, the air supply area is the sum of the effective areas of each filter;

4. Air supply distance : The distance from the air outlet surface to the target area will affect the actual wind speed reaching the target area;

5. Return air path : Whether the return air is smooth will affect the air supply effect and wind speed stability.

The relationship between air volume and wind speed is: air volume = target wind speed × effective air supply area . After confirming the air supply area, the required air volume can be deduced and then matched to the fan operating point.

3. Setting sequence of outlet wind speed

It is recommended to set the EFU outlet wind speed in the following order:

Step 1: Confirm the cleanliness target
and clarify the target cleanliness level, particle control requirements and process conditions.

Step 2: Confirm that the effective air supply area
is calculated according to the actual air outlet area of ​​the filter, excluding frames, sealing strips and structural obstructions.

Step 3: Determine the target wind speed,
combine the cleanliness target and equipment structure, and determine the target surface wind speed and its allowable deviation range.

Step 4: Reverse the required air volume.
Air volume = target wind speed × effective air supply area, and make appropriate corrections based on the air supply distance and return air conditions.

Step 5: Match the fan working point,
combine the filter resistance and system resistance, and confirm the fan working point at the target air volume.

Step 6: Confirm the uniformity.
Measure the wind speed distribution on the wind outlet surface through the arrangement of measuring points to confirm whether the uniformity requirements are met.

4. Uniformity confirmation method

The outlet wind speed should not only look at the average value, but also confirm whether the distribution is even. Key points for uniformity confirmation include:

1. Measurement plane : usually selected at a certain distance from the air outlet surface, the specific distance is agreed upon by the project;

2. Number of measuring points : calculated based on air supply area, at least 1 measuring point for each filter;

3. Measuring point distribution : evenly cover the center and edge areas to avoid measuring only the center point;

4. Average calculation : add the wind speed at each measuring point and divide by the number of measuring points;

5. Non-uniformity evaluation : available (maximum wind speed − minimum wind speed) ÷ average wind speed × 100% evaluation;

6. Measure working conditions : Confirm the status of the filter and the operating status of the fan to avoid differences in working conditions affecting the results.

If the wind speed is found to be uneven, it can be investigated from three aspects: fan position, filter status and structural shielding. For specific analysis methods, please refer towhat to do if the EFU air outlet speed is uneven .Troubleshooting ideas on

5. Wind speed setting reference in different equipment scenarios

For ultra-thin or space-constrained devices, please refer to70mm ultra-thin EFU andThe structural plan of the fan filter unit of the small-sized EFU equipment confirms the matching relationship between the wind speed setting and the box structure.

6. Information required for wind speed setting

It is recommended to provide: when communicating with the project:

1. Target cleanliness levels and particle control requirements;

2. Effective air supply area and filter specifications;

3. The distance from the wind outlet surface to the target area;

4. Return air path and site layout;

5. Target wind speed and allowable deviation range;

6. Filter resistance and system resistance information;

7. Fan model and control method;

8. Acceptance measurement methods and judgment values.

7. Aili Industrial EFU wind speed setting supporting capabilities

Aili Industrial has the following supporting conditions in terms of EFU wind speed setting:

• Fan matching : self-produced EC, DC, AC motors and fans, which can match the air volume parameters according to the target wind speed;

• Self-produced filters : It has the production capacity of HEPA and ULPA filters, and can control the filter specifications and resistance consistency;

• Structural design : The internal structure and diffusion space of the box can be designed according to the equipment space to improve wind speed distribution;

• Whole machine verification : conduct wind speed, air volume and operation tests before leaving the factory;

• Customization capabilities : The cabinet, air inlet and outlet methods, and installation structure can be customized according to the equipment space.

For more product information, please refer toEquipment-side fan filter unit (EFU)、Custom EFU andDC EFU equipment fan filter unit。

FAQ

At what speed is the EFU outlet wind speed generally set?

It needs to be confirmed based on the cleanliness target, air supply area and equipment structure. Different applications have different wind speed ranges, and it is not appropriate to directly apply fixed values.

How to confirm the air supply area?

Based on the actual air outlet area of ​​the filter, excluding the area occupied by the frame and sealing strip, and taking into account structural obstruction and multi-filter configuration.

What is the relationship between outlet wind speed and air volume?

Air volume = target wind speed × effective air supply area. After confirming the air supply area, the required air volume can be deduced.

How to confirm the uniformity of wind speed?

Arrange the measuring points on the agreed measurement plane, and calculate the average value and unevenness after measuring point by point. The specific judgment standards are agreed with the project party.

How to determine the number of measuring points?

Calculated based on the air supply area, the larger the area, the more measuring points. Each filter measures at least 1 point and covers the center and edge areas.

Will the wind speed decrease after the filter resistance increases?

meeting. After the filter contains dust, the resistance increases. If the fan speed remains unchanged, the air volume will decrease and the outlet wind speed will decrease accordingly.

What to do if the wind speed is uneven?

It can be checked from three aspects: fan position, filter status and structural obstruction. For specific methods, please refer to the troubleshooting idea of ​​uneven wind speed.

What should I pay attention to when setting the wind speed of ultra-thin EFU?

It is necessary to confirm the diffusion space inside the box and the filter area to avoid uneven distribution of wind speed due to limited space.

The content of this article is for reference only, please confirm with the actual project. The wind speed settings, air supply area calculations, measuring point layout and judgment values ​​involved in this article may vary depending on product models, project conditions and actual working conditions. For specific EFU solutions, please refer to the actual confirmed product technical documents, drawings and test results.