How to arrange the distance between ULPA air supply and return air? Airflow paths and device interfaces

There is no fixed value for the distance between the air supply and return air of the ULPA filter that applies to all rooms. The complete air path should be arranged according to the space, equipment, heat source and process exhaust. Distance is only one factor in layout. The arrangement of the distance between supply air and return air essentially answers 'where does the air come in, what does it pass through, and where does it go out'. If the distance is too close, the air flow will be short-circuited and the clean air will be sucked away without passing through the workpiece; if the distance is too far, the path will be easily blocked by equipment or personnel, and the direction of the air flow will change. The reasonable range of distance depends on the location of the protected object, space height, equipment layout and heat source distribution, rather than a fixed value that can be looked up in a table. Aili Industry isFFU fan filter unit andWhen matching the fan filter unit at the EFU equipment end , check the position of the air supply surface and the return air path in the same plan.The FFU computer group control system records the air volume and pressure distribution in the zones. When adjusting the distance between supply air and return air, the actual measured data can be compared with the design intention.

1. Track the air flow from the protected area: does the air pass through the workpiece?

Confirm whether the air can reach the return air after passing through the workpiece, and will not be sucked away by the near-end return air in advance, and will not bring contamination from personnel or equipment to sensitive surfaces.

The criterion for judging the reasonableness of the distance between supply air and return air is whether the air flow passes through the protected object. If the return air outlet is too close to the air supply surface and is located in front of the workpiece, the airflow will take the shortest path directly into the return air outlet, and the workpiece will not be effectively protected. If the return air outlet is far away from the workpiece and there are obstacles in the path, the airflow may be detoured, and the workpiece is also insufficiently protected. Aili Industry isIn the HEPA/ULPA filter matching plan, the air flow path design intention is explained according to the workpiece location and return air conditions.The FFU fan filter unit complete machine test records the regional air volume and pressure distribution. During path evaluation, the reasonable distance between the supply air and return air can be deduced from the position of the workpiece. The relationship between grade and airflow requirements can be found inISO cleanliness level comparison。

2. Consider height and occlusion: plane distance is not equal to the actual path

The same plane distance may produce different paths under different heights, partitions and equipment layouts. The distance cannot be measured only on the plane map.

The distance between the air supply outlet and the return air outlet on the plan view is geometric distance, and the actual air path is three-dimensional. Different ceiling heights, equipment or partitions in the middle, and return air outlets at different heights will all cause the airflow to take different paths. Aili Industry isthe EFU equipment end fan filter unit, confirm the air flow channel according to the equipment height and internal structure.When matching Compact models such as ultra-thin EFU balance the air outlet direction and return air conditions within a limited height.The non-standard ULPA filter project can evaluate the feasibility of the return air distance according to the spatial profile. The relationship between height and airflow path can be referred toHEPA FAQs and Selection Guide。

3. The heat source and process exhaust will change the path: we cannot just look at the geometric layout

Equipment heating creates updrafts and process exhaust changes local pressure, both of which can deviate from the actual airflow path from the geometric arrangement. The airflow direction above the heat source may be upward, opposite to the air supply direction; when the process exhaust volume is too large, the surrounding air will be drawn toward the exhaust port, changing the air supply and return path.

Aili Industry isFFU fan filter unit andthe EFU equipment end fan filter unit, the air supply parameters can be checked based on the equipment heat load and exhaust conditions.When matching The FFU computer group control system records the air volume and pressure under different operating modes, and checks the path according to the actual status of the heat source and exhaust air during the test. The relationship between heat source and air flow path can be referred toULPA ultra-high efficiency filter FAQ and selection guide。

4. When the return air outlet is near the top of the workpiece, it is necessary to evaluate whether there is an air supply short circuit.

When the return air outlet is near the top of the workpiece, it should be evaluated whether there is a short circuit in the air supply. It cannot be judged just based on the return air volume reaching the standard. When the return air outlet is positioned higher than or close to the workpiece, the clean air may come out of the air supply surface and directly enter the return air outlet, leaving the workpiece outside the airflow path.

Aili Industry isNon-standard ULPA filters andFFU fan filter unit package, the short circuit risk is evaluated based on the position of the return air outlet and the height of the workpiece.In the The EFU equipment-side fan filter unit equipment-side solution can confirm the air outlet direction according to the position of the workpiece, allowing the airflow to pass through the workpiece before being discharged. The relationship between return air layout and short circuit can be referred toEFU FAQ and technical support。

5. Verify according to actual operation: turn on the relevant return and exhaust air at the same time

At the same time, turn on the relevant return and exhaust air, observe or measure the path and regional performance, and check the relationship between adjacent workstations and pressure after rectification.

The distance and layout in the design stage are the basis, and the actual effect must be confirmed in real operating conditions. Open the supply air, return air and process exhaust air at the same time, operate the door and equipment according to the actual status, and observe whether the air flow passes through the protected area according to the designed path. Aili Industry isFFU fan filter unit andThe fan filter unit at the EFU equipment end supports zone speed adjustment.The FFU computer group control system records the zone air volume, pressure and operating mode, and can compare the design parameters according to the actual operating status during verification. For actual operation verification methods, please refer toHEPA FAQs and Selection Guide。

6. Related questions and answers

Is the farther away the return wind is, the better?
Too far may also increase retention and obstruction, which should be determined based on reasonable air paths and verification results.

If the distance on the floor plan is appropriate, will the actual airflow be reasonable?
uncertain. Height, occlusion, heat source and process exhaust will all change the actual path and need to be verified under real operating conditions.

The return air outlet is near the top of the workpiece. Is it definitely a short circuit?
Needs assessment. The risk of short circuit is higher when the return air outlet is close to the workpiece, but it also depends on the air supply direction, air volume and height of the workpiece, and should be confirmed through testing.

7. Related articles

ULPA ultra-high efficiency filter FAQ and selection guide

Ultra-thin EFU

FFU equipped with ULPA ultra-high efficiency filter

HEPA FAQs and Selection Guide

8. Key points for selection and acceptance inspection

9. Product matching and technical support from Aili Industrial

Aili Industry isFFU fan filter unit andWhen matching the fan filter unit at the EFU equipment end , check the position of the air supply surface and the return air path in the same plan.The FFU computer group control system records the zone air volume, pressure and operating mode. When adjusting the distance between supply air and return air, the actual measured data can be compared with the design intention.The HEPA/ULPA filter matching solution explains the airflow path design intention according to the workpiece location and return air conditions.The FFU fan filter unit complete machine test records the regional air volume and pressure distribution;The fan filter unit at the EFU equipment end is equipped to confirm the air flow channel according to the height and internal structure of the equipment.The ultra-thin EFU balances the air outlet direction and return air conditions within a limited height.The non-standard ULPA filter project evaluates the feasibility of the return air distance based on spatial profile.FFU fan filter unit andThe EFU equipment end fan filter unit can be used to check the air supply parameters based on the equipment heat load and exhaust conditions.The FFU computer group control system records the air volume and pressure in different operating modes. During the test, the path is checked according to the actual status of the heat source and exhaust air. When the return air outlet is close to the workpiece, short circuit risk assessment is performed and the air outlet direction is adjusted. 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.