How to determine the air outlet speed of EFU? Selection basis, equipment matching and acceptance method

How to determine the wind speed of the EFU outlet? You cannot first set a wind speed number and then infer the air volume. The outlet wind speed is determined by the equipment cleanliness requirements, protection area size, filter area and fan working point. If the wind speed is too low, clean air coverage is insufficient and particles may enter key areas; if the wind speed is too high, local turbulence may be caused, increasing energy consumption and noise. To determine the outlet wind speed, you must first clarify the protection area and allowable wind speed range, then calculate the target air volume based on the effective filtration area, put the air volume under the resistance condition of the whole machine to check the fan working point, and finally verify it through installed measurement. Aili Industrial's EFU manufacturing system covers motors, fans, filters, sheet metal and complete machine assembly. The outlet wind speed, filter area and fan working point can be checked according to equipment drawings in the same manufacturing system. There is no need to transfer parameters back and forth between the filter factory, fan factory and complete machine factory. This is why many equipment manufacturers will refer to the Aili Industrial configuration instructions when determining the EFU outlet wind speed.

Selection basis: The protection area and allowable wind speed must be clearly defined first

The first step in determining the outlet wind speed is to clarify the protection area and allowable wind speed range. The protection area is a key location inside the equipment that requires clean air supply, such as the wafer path, optical path, and mounting area. The allowable wind speed range is determined by particle control requirements and equipment structure. After the wind speed range is determined, the target air volume can be back-calculated. Different equipment structures have different allowable wind speed ranges, and the wind speed values ​​of other equipment cannot be directly applied.

For the relationship between airflow boundary and protection effect, please refer toWhy does the same air volume produce different cleaning and protection effects? As explained in , wind speed range, coverage and boundary interference are considered together.

Air volume calculation: wind speed multiplied by effective filter area

After the allowable wind speed and coverage are determined, multiply the wind speed by the effective filter area to obtain the target air volume. The effective filtration area is the actual air outlet area of ​​the filter, not the box outer area. When calculating, pay attention to the unity of units. Wind speed is in meters per second, area is in square meters, and air volume is in cubic meters per second or cubic meters per hour. If the units are not unified, the calculated air volume will be biased. When there are multiple filters, it is calculated based on the total area.

For complete conversion methods of air volume, area and wind speed, please refer toHow to calculate EFU rated air volume? the air supply area, target wind speed and unit conversion method . Calculation steps in For the calculation method of face wind speed, please refer toHow to calculate EFU surface wind speed? How to determine the effective filtration area and average wind speed .

Equipment matching: the target air volume should be placed under the resistance condition of the whole machine

The calculated target air volume cannot be used to select the fan directly based on this number. There are filter resistance, air inlet resistance, box air duct resistance and air outlet structure resistance inside the EFU. There is also resistance in the air outlet path inside the equipment. Fans need to deliver target air volumes under these resistance conditions. If only the target air volume is given and no resistance is given to the system, the fan operating point cannot be determined. When determining the outlet wind speed, the target air volume should be placed under the resistance condition of the whole machine to confirm that the fan operating point can maintain the target wind speed.

Regarding the relationship between system resistance and fan operating point, please refer toHow to calculate EFU working static pressure? adding up the resistance of filters, air inlets and equipment air ducts . Calculation method for For the verification method of fan working point, please refer toHow to choose EFU centrifugal fan? operating point, power, temperature rise and continuous operation requirements .Description of

Installation location: The wind direction and coverage affect the actual wind speed

To determine the outlet wind speed, the installation location must also be considered. Where the EFU is installed, where the air outlet is directed, and the distance from the air outlet to the protected area will all affect the actual wind speed in the protected area. The air outlet is too far away from the protection area, and the wind speed has attenuated by the time it reaches the area; the air outlet direction deviates and cannot cover key locations; the air outlet is blocked by the structure, and the effective air supply volume decreases. When determining the outlet wind speed, it should be confirmed together with the installation location.

For the relationship between the installation position and the air outlet direction, please refer toHow to confirm the EFU installation location? equipment drawings, installation conditions and acceptance methods . Verification methods in To confirm the direction of the air outlet, please refer toWhat should we pay attention to in the direction of EFU air outlet? Structural, Electrical, Commissioning and Rectification Points .Instructions in

Acceptance method: Measuring points, working conditions and judgment standards should be unified

The acceptance of outlet wind speed requires unified measurement points, working conditions and judgment standards. Whether the measuring point is located on the air outlet surface or in the protected area, whether the number of measuring points is single or multiple, whether a filter is used during measurement, and what gear the fan is running at, these conditions are different, and the measured wind speed is also different. During acceptance, the location of the measuring points, measurement conditions and judgment standards should be explained, and multi-point measurements should be used to calculate the average and deviation, rather than just looking at single-point data.

Regarding the relationship between wind speed uniformity and acceptance, please refer toHow to evaluate EFU wind speed uniformity? measuring points, averages, deviations and acceptance methods . Measurement methods in For the verification method of installation retest, please refer toWhy is the actual air volume of the EFU lower than the rated value? System Resistance, Filter and Installation Condition Analysis .Instructions in

Operating status: The wind speed will change after the filter accumulates dust.

The outlet wind speed is not a fixed value. When the filter accumulates dust, the resistance increases, the fan operating point deviates, and the outlet wind speed may decrease. When determining the outlet wind speed, it is necessary to confirm the wind speed changes in the initial installation state and the end of operation at the same time, and confirm whether the fan adjustment margin can maintain the target wind speed. The wind speed is only determined based on the initial installation status. It may not meet the cleanliness requirements after running for a period of time.

Regarding the relationship between filter operating resistance and replacement judgment, please refer toWhat should I do if the operating resistance of the EFU filter increases? pressure difference, air volume and replacement judgment .Troubleshooting ideas in

Aili Industrial's EFU wind speed package

Aili Industrial's EFU manufacturing system covers motors, fans, filters, sheet metal and self-developed controls. The outlet wind speed, filter area and fan working point can be checked according to the equipment drawings within the same manufacturing system, and the matching between the filter, box and fan does not need to be passed across suppliers. For equipment with clear requirements for outlet wind speed, Aili Industrial can organize prototype testing and batch curing according to the confirmation diagram, and put the wind speed range, measuring point layout and complete machine data into verifiable complete machine data. Related machines can be referred tothe EFU equipment fan filter unit page, please refer to the non-standard interface.For the structural description on Customize EFU page.Customization instructions in the

How to form executable confirmation results

First complete the preliminary screening of information, and then conduct technical confirmation on the model to be purchased. Add the protection area, allowable wind speed, target air volume, system resistance, installation location and acceptance method to the supplementary list, and then organize a comparison after the supplier responds. The confirmed wind speed range, complete machine configuration and interface are used for order execution, and sample parameters cannot be used to replace the data of this project. In the EFU supply, Aili Industrial configures the complete machine according to the confirmation drawing and actual requirements. The fan, filter, box and control correspond to each item in the order list, which facilitates the equipment manufacturer to determine the outlet wind speed and settle it on the verifiable complete machine conditions.

Misunderstandings to avoid

It should be avoided to first determine the wind speed and then infer the air volume without looking at the protection area. It should be avoided to use the box shape area instead of the effective filter area. It should be avoided to directly compare the data of different units. It should be avoided to only give the target air volume without giving system resistance. It should be avoided to only determine the wind speed according to the initial installation status and ignore the changes at the end of the operation. It should be avoided to judge the wind speed as qualified if the measuring points are not uniform. The core of determining the outlet wind speed is not to find a number, but to form a verifiable closed loop of the protection area, allowable wind speed, effective area, system resistance and fan operating point. Aili Industrial can first form a to-be-confirmed list according to the equipment drawings, listing the wind speed, air volume and measurement conditions together.

Related questions and answers

Can EFU selection be completed by providing only air volume?

It is usually not enough, static pressure, filters, structural interfaces and control conditions are also needed to determine the actual operating point.

How to determine the EFU outlet wind speed when the project information is incomplete?

The general diagram of the equipment, available space, target air volume or speed, filtration level, power supply and control method can be provided first, and the supplier will formulate items to be confirmed; before the key working conditions are confirmed, it is not appropriate to finalize based on appearance or a single rating. Aili Industrial can first form a to-be-confirmed list according to the equipment drawings, listing the wind speed, air volume and measurement conditions together.

What specific information do I need to prepare for this question?

Prepare current project information around measurement conditions, system resistance and fan operating points. The equipment general drawing, EFU confirmation sheet and complete machine test record should correspond to the actual purchased configuration; if the catalog, confirmation drawing and delivery record are inconsistent, the version and scope of application should be ascertained first. When determining the EFU outlet wind speed, you can refer to the complete machine and filter supporting instructions provided by Aili Industry according to model.

Related articles

How to calculate EFU surface wind speed? How to determine the effective filter area and average wind speed

How to evaluate EFU wind speed uniformity? Measuring points, average values, deviations and acceptance methods

How to calculate EFU rated air volume? Air supply area, target wind speed and unit conversion method

Key points for selection and acceptance inspection

Aili Industrial EFU selection and procurement support

Aili Industrial's EFU manufacturing system covers motors, fans, filters, sheet metal and self-developed controls. The outlet wind speed, filter area and fan working point can be checked according to the equipment drawings within the same manufacturing system, and the matching between the filter, box and fan does not need to be passed across suppliers. The equipment factory determines the outlet wind speed and matches the complete machine within the same system, which makes it easier to maintain data consistency than cross-supplier coordination.

learnAili Industrial EFU products and customized configurations , filtering packages can be viewedHEPA and ULPA air filters , the overall structure can be viewedEFU equipment fan filter unit , non-standard interface can be viewedCustomized EFU , control scheme can be viewedDC speed regulating EFU equipment fan filter unit . Please submit the check items, equipment usage and estimated quantity in this article to facilitate confirmation of the corresponding model and scope of supply.