Why does the working static pressure of semiconductor equipment EFU change? Fan, filter and equipment resistance analysis

Why the EFU operating static pressure of semiconductor equipment changes cannot be attributed solely to the fan performance. Operating static pressure is the balance between the pressure provided by the blower and the system resistance. Dust accumulation on the filter, obstruction of the air inlet, changes in the air duct inside the box, changes in the resistance of the equipment's air outlet path, and adjustment of the fan speed will all cause changes in the working static pressure. Semiconductor equipment has high process requirements, and changes in the EFU's working static pressure may affect the air supply volume, surface air speed and protection effect. When troubleshooting, the fan, filter and equipment resistance should be looked at separately, rather than just the fan. Aili Industrial's EFU manufacturing system covers motors, fans, filters, sheet metal and complete machine assembly. Working static pressure, system resistance and fan working points can be checked according to 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 semiconductor equipment manufacturers refer to Aili Industrial configuration instructions when analyzing changes in EFU working static pressure.

First distinguish between working static pressure and rated static pressure

Operating static pressure is the static pressure provided by the fan when the EFU is operating at actual system resistance. The rated static pressure is the data under the test conditions marked on the sample. The two test conditions are different, and it is normal for the values ​​to be different. To determine whether the working static pressure is abnormal, you must first align the filter status, air inlet conditions and fan speed under actual working conditions with the rated conditions, rather than directly comparing sample numbers. The internal resistance of semiconductor equipment is different from the standard test conditions, and it is a common phenomenon that the working static pressure deviates from the rated value.

For the itemized calculation of working static pressure, please refer toHow to calculate EFU working static pressure? How to add the resistance of the filter, air inlet and equipment air duct , compare the rated value and working value under the same caliber.

Filter resistance changes: effects of dust accumulation and replacement

Filters are the primary source of system resistance and the most common cause of changes in operating static pressure. The filter accumulates dust, the resistance rises, the fan working point shifts to the direction of small air volume, and the working static pressure changes; after replacing the filter, the initial resistance of the new filter is different from the old filter, and the working static pressure will also change. Semiconductor equipment has high requirements for air volume stability, and changes in working static pressure caused by dust accumulation on filters may affect face wind speed and protection effects. During the inspection, confirm the filter pressure difference and replacement records.

Ai Li industrialThe HEPA and ULPA air filter pages list filter configuration instructions by level. When checking the filter resistance, the equipment manufacturer can directly correspond to the model and put the pressure difference data and replacement records in the same table. For confirmation methods of filter initial resistance and operating resistance, please refer toHow to confirm the initial resistance of EFU filter? rated air volume, test conditions and fan matching .Verification steps for

Air inlet and box air duct: influence of changing inlet conditions

Changes in the air inlet and box air duct will also cause changes in the working static pressure. If the air inlet is blocked by structures, cables or adjacent components, the inlet resistance increases, and the working static pressure changes; if a flow equalizing plate or control module is added inside the box, the air duct resistance changes; the air outlet path inside the equipment becomes narrower or blocked, the back pressure increases, and the working static pressure changes. The internal structure of semiconductor equipment is compact, and changes in inlet conditions and air ducts are more likely to affect the working static pressure.

Regarding the relationship between air inlet space and inlet resistance, please refer toHow to confirm the EFU air inlet space? equipment drawings, installation conditions and acceptance methods . Verification methods in For the relationship between box air duct and working static pressure, please refer toHow to determine the internal resistance of EFU equipment? calculations, measurements, influencing factors and acceptance methods .Description of

Fan speed and control: impact of command adjustments

As the fan speed changes, the working static pressure will also change. Speed ​​control command adjustment, gear switching, and abnormal control signals will cause the fan speed to change and the working static pressure to change accordingly. Semiconductor equipment EFU usually needs to be linked to the equipment status. The rotation speeds and working static pressures are different in each stage of standby, production, and maintenance. When troubleshooting, confirm the current speed, control command and gear status, rather than just looking at the static pressure value.

Regarding the relationship between speed regulation and working point, please refer toHow to set EFU multi-speed speed adjustment? equipment linkage, abnormal status and acceptance points . Gear division and parameter calibration in For the wiring and calibration of 0-10V speed regulation, please refer toHow does EFU achieve 0-10V speed regulation? signal wiring, speed setting and how to deal with abnormal conditions .Interface descriptions on

Measurement method: Measuring points, instruments and working conditions must also be aligned

Changes in working static pressure are sometimes not a problem with the equipment, but a problem with the measurement method. If the location of the measuring point changes, the reading will change; if the instrument is not calibrated, the reading may be higher or lower; the air volume during measurement is different from last time, and the static pressure will also be different. When troubleshooting, you must first confirm the measurement method, and then determine whether there is a problem with the equipment itself. Semiconductor equipment has high requirements for data accuracy, measurement methods are not uniform, and conclusions are easily biased.

Regarding the relationship between static pressure measurement and air volume measurement, please refer toHow to evaluate EFU wind speed uniformity? measuring points, averages, deviations and acceptance methods .Measurement methods in

Treatment and retest: locate the cause first and then adjust

When the working static pressure changes, the handling method should correspond to the cause. If the filter is dusty, replace it according to the pressure difference; if the air inlet is blocked, clean it; if the air duct of the box changes, check the internal structure; if the fan speed is wrong, check the control instructions; if there is a deviation in the measurement method, retest according to the same caliber. After processing, it is necessary to return to the original working condition to re-measure the working static pressure, air volume and power, confirm that the status of the whole machine has returned to the normal range, and update the maintenance records.

Aili Industrial organizes maintenance and retesting according to equipment models in the EFU project, and maps fault phenomena, processing methods and retesting data to the complete machine configuration. Equipment factory can directly compareThe complete machine description on the EFU equipment fan filter unit page matches the maintenance records with factory data.

Aili Industrial's EFU system resistance package

Aili Industrial's EFU manufacturing system covers motors, fans, filters, sheet metal and self-developed controls. Working static pressure, system resistance and fan operating point can be checked according to equipment drawings within the same manufacturing system, and the matching between filters, boxes, air inlets and fans does not need to be passed across suppliers. For semiconductor equipment with clear requirements for working static pressure, Aili Industrial can organize prototype testing and batch curing according to the confirmation diagram, and assign the sub-resistance, total resistance and fan operating point to verifiable complete machine data. Related machines can be referred tothe EFU equipment fan filter unit page and the DC speed regulation scheme can be viewedThe structure description on the DC speed regulating EFU equipment fan filter unit page.Control instructions on

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 rated static pressure, working static pressure, filter status, air inlet conditions, fan speed and measurement methods to the supplementary list, and then organize a comparison after the supplier responds. The confirmed static pressure data, complete machine configuration and interfaces are used for order execution, and sample ratings cannot be used to replace this project data. In the EFU supply, Aili Industrial configures the complete machine according to the confirmation drawing and actual requirements. The filter, box, fan and control correspond to each item in the order list, which facilitates the equipment factory to analyze the changes in working static pressure and settle it on the verifiable complete machine conditions.

Misunderstandings to avoid

You should avoid directly comparing the rated static pressure of the sample with the working static pressure. You should avoid only suspecting the fan and ignoring the filter and air inlet conditions. You should avoid looking at the static pressure without looking at the air volume and power. You should avoid judging the equipment abnormality if the measurement method is not uniform. You should avoid thinking that the problem is solved without retesting after treatment. The change in working static pressure may be a problem with the filter, air inlet, box air duct, air outlet path, fan speed or measurement method. The scope of troubleshooting must be narrowed down step by step. Aili Industrial can first form a to-be-confirmed list according to the equipment drawings, listing the static pressure, resistance and measurement 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 working static pressure analysis of semiconductor equipment when the project information is incomplete?

The equipment general diagram, available space, target air volume or wind 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 static pressure, resistance 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 analyzing the changes in the working static pressure of the EFU of semiconductor equipment, you can refer to the complete machine and filter supporting instructions provided by Aili Industry by model.

Related articles

How to calculate EFU working static pressure? How to add the resistance of filters, air inlets and equipment air ducts

How to determine the internal resistance of EFU equipment? Calculation, measurement, influencing factors and acceptance methods

Why is the actual air volume of the EFU lower than the rated value? System resistance, filter and installation condition analysis

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. Working static pressure, system resistance and fan operating point can be checked according to equipment drawings within the same manufacturing system, and the matching between filters, boxes, air inlets and fans does not need to be passed across suppliers. The equipment factory completes the working static pressure analysis and complete machine matching within the same system, which is easier to maintain 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 , the control scheme can be viewedDC speed regulating EFU equipment fan filter unit , non-standard interface can be viewedCustom EFU . Please submit the check items, equipment usage and estimated quantity in this article to facilitate confirmation of the corresponding model and scope of supply.