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

How to evaluate the uniformity of EFU wind speed? You cannot draw a conclusion just by measuring one point. The evaluation of wind speed uniformity depends on the measurement point layout, measurement working conditions, average value and dispersion degree. There are too few measuring points to represent the entire air outlet surface; the measuring points are not located in the effective area, and the measured values ​​cannot reflect the actual protection area; the measurement conditions are inconsistent and the data cannot be compared; only looking at the average value without looking at the deviation, local low-speed areas may be covered up. To evaluate the uniformity of wind speed, it is necessary to judge based on grid measurement points, unified working conditions, multi-point measurements, calculation of average values ​​and deviations, and combined with the actual needs of the protected area. Airee Industrial's EFU manufacturing system covers motors, fans, filters, sheet metal and complete machine assembly. The wind speed distribution on the air outlet surface and the complete machine working point can be checked according to the equipment drawings within the same manufacturing system. There is no need to go back and forth between the fan factory, filter factory and complete machine factory for confirmation. This is why many equipment manufacturers will refer to Airee Industrial configuration instructions when evaluating the uniformity of EFU wind speed.

Measuring point layout: grid covers the entire air outlet surface

The first step in wind speed uniformity evaluation is to arrange measuring points. The measuring points must cover the entire effective air outlet surface according to the grid, and cannot only measure the center point, nor only a few edge points. The grid density is determined based on the size and accuracy requirements of the air outlet surface. The larger the air outlet surface, the higher the uniformity requirements and the more measuring points. The location of the measuring points should be recorded clearly to facilitate retesting and comparison.

Ai Li industrialEFU products and customized configurations list the air outlet size and structure description by model. When arranging measuring points, the equipment manufacturer can directly correspond to the specific model, and check the measuring point location and the air outlet diagram together.

Measurement conditions: with filter element and external static pressure must be written clearly

Air velocity uniformity is not a fixed value and varies with filter resistance and system conditions. When measuring, it is necessary to indicate whether there is a filter, what the static pressure outside the machine is, what the fan speed or control gear is, and where the measurement plane is on the air outlet surface. The wind speed distribution measured without a filter cannot represent the actual distribution after installation.

For the relationship between measurement working conditions and air volume, please refer toHow to calculate EFU rated air volume? the air supply area, target wind speed and unit conversion method . The calculation caliber 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 .

Mean and deviation: In addition to the mean, the degree of dispersion depends on

When evaluating wind speed uniformity, you cannot just look at the average value. The average value meets the standard, but it does not mean that every position meets the standard. To calculate the average value and degree of dispersion of each measuring point, it is often expressed as relative standard deviation or maximum deviation. A large degree of dispersion indicates that the wind speed is unevenly distributed, and there may be low-speed or high-speed areas locally. If the protected area falls in a low-velocity area, particles may enter; high-speed areas may cause turbulence and noise.

Regarding the relationship between wind speed distribution and protection effect, please refer toWhy does the same air volume produce different cleaning and protection effects? In the instructions, the average value, deviation and protected area location are evaluated together.

Acceptance method: Judgment standards must be agreed in advance

For the acceptance of wind speed uniformity, the judgment criteria must be agreed in advance. How much the relative standard deviation should be controlled, how much the maximum deviation should not exceed, and whether the low-speed zone is allowed to fall into the protection zone should be clearly stated in the technical agreement. When accepting, judge according to the agreed standards, rather than setting standards after testing. The judgment criteria are unclear and the acceptance conclusion is prone to disagreement.

In the EFU project, Aili Industries organized wind speed uniformity measurements according to the equipment drawings and agreed working conditions, and wrote the judgment criteria, measuring point plan and measurement working conditions into the confirmation document. For items involving complete machine acceptance, please refer toHow to confirm the EFU installation location? equipment drawings, installation conditions and acceptance methods .Acceptance ideas in

Structural influence: flow diversion, flow equalization and air outlet structure

Wind speed uniformity is affected by the box structure. The air inlet guide structure, the internal flow plate of the box, and the design of the air outlet structure will all affect the wind speed distribution on the air outlet surface. The airflow is unreasonable and the airflow is biased to one side; the airflow plate is missing and the airflow is concentrated in the middle; the air outlet structure is asymmetrical and the wind speed is unevenly distributed. When evaluating uniformity, the judgment should be combined with the box structure, not just the measurement data.

Regarding the relationship between box structure and airflow organization, please refer toHow to design the EFU box? strength, sealing, air inlet and outlet and maintenance points .Structural verification methods for

Installation retest: re-confirm after installation

Wind speed uniformity may differ between EFU unit testing and installation. After installation, the internal air outlet path, return air conditions and surrounding structures of the equipment will all affect the wind speed distribution. The installation retest should be measured according to the same measuring point plan under the target air volume, and compared with the unit test data. When the difference is large, check the installation position, air inlet clearance, and air outlet path instead of directly determining that there is a problem with the EFU itself.

Regarding the relationship between installation retest and installation location, please refer toHow to confirm the EFU air inlet space? equipment drawings, installation conditions and acceptance methods .Verification methods in

Aili Industrial's EFU wind speed uniformity package

Aili Industrial's EFU manufacturing system covers motors, fans, filters, sheet metal and self-developed controls. The wind speed distribution on the air outlet surface and the working point of the complete machine can be checked according to the equipment drawings within the same manufacturing system. The air guide structure, flow equalization design and complete machine interface do not need to be transferred between multiple suppliers. For equipment that requires uniformity of wind speed, Aili Industrial can organize prototype testing and batch curing according to the confirmation diagram, and put the measuring point plan, judgment standards 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. Include the measurement point layout, measurement working conditions, average value and deviation, judgment standards and installation retest in the supplementary list, and then organize the comparison after the supplier responds. The confirmed measuring point plan, judgment standards and complete machine configuration 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 evaluate the wind speed uniformity on the verifiable complete machine conditions.

Misunderstandings to avoid

It should be avoided to measure only one point in the center to represent the entire air outlet surface. It should be avoided to measure the wind speed distribution without a filter element. It should be avoided to only look at the average value without looking at the deviation. It should be avoided to determine the judgment standard after the measurement. It should be avoided to consider the uniformity as qualified without retesting after installation. The core of wind speed uniformity evaluation is not to find an average wind speed, but to cover the measuring points, unify the working conditions, look at the mean and deviation together, and agree on the judgment standards in advance. Aili Industrial can first form a to-be-confirmed list according to the equipment drawings, listing the measuring points, working conditions and judgment conditions together.

Related questions and answers

Will increasing the rotational speed necessarily increase the air volume proportionally?

uncertain. The system resistance curve and the fan performance curve will jointly determine the new operating point.

How to promote EFU wind speed uniformity evaluation when 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 measuring points, working conditions and judgment 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 evaluating the EFU wind speed uniformity, you can refer to the complete machine and structural supporting instructions provided by Aili Industry by model.

Related articles

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

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

How to determine the EFU outlet wind speed? Selection basis, equipment matching and acceptance 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 wind speed distribution on the air outlet surface and the working point of the complete machine can be checked according to the equipment drawings within the same manufacturing system. The air guide structure, flow equalization design and complete machine interface do not need to be transferred between multiple suppliers. The equipment factory completes the wind speed uniformity evaluation and complete machine matching 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.