What does the EFU filter do? Position and usage boundaries of equipment-side clean air supply

What does the EFU filter do? You can't just answer 'filtering particles'. The EFU filter is responsible for intercepting particles in the air path and is the last barrier for clean air supply. Its scope of action is the path after the air outlet surface of the filter and before it is sent to the protected area, including the efficiency of the filter itself, the seal between the filter and the box, and the cleanliness of the air supply path. If the filter grade is selected high, but the sealing is not in place, the risk of bypass still exists; if the filter is installed correctly, but the air supply path is contaminated, the protection effect will be compromised. To understand the role of the EFU filter, you need to look at its position in the air path, where the filter boundary is, how it cooperates with the fan and box, and which problems are not within the scope of the filter. Aili Industrial's EFU manufacturing system covers motors, fans, filters, sheet metal and complete machine assemblies. The filter's efficiency, resistance, sealing and complete machine 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 Aili Industrial product descriptions when understanding the functions of EFU filters and planning and selection.

Position in the air path: Filtration is the last step before air supply

The EFU filter is located in the air path after the fan and before the air outlet (or after the air inlet and before the fan, depending on the structure), responsible for intercepting particles before the air supply. Air enters from the air inlet, passes through the filter, and is pressurized by the fan before being sent out; the position of the filter determines which section of air it intercepts. The filter is placed in front of the fan to protect the inside of the fan; the filter is placed after the fan to ensure the cleanliness of the sent air. The positions of different structures are different, and the action boundaries of filters are also different.

Regarding the composition and working principle of EFU in the whole machine, please refer toWhat is EFU? The structure, function, working principle and applicable equipment description are explained in the description, and the function of the filter is understood in the air path of the whole machine.

Filter boundary: level determines interception capability, sealing determines actual effect

The filtration boundary of the EFU filter is determined by the filter grade and sealing status. The grade determines how large particles can be intercepted, and the sealing determines whether there is a bypass of unfiltered air. If the grade is selected high and the sealing is not in place, the actual protection effect will still be reduced; if the grade is selected appropriately and the sealing is reliable, the filter can play its role. The filter boundary is not the line on the filter outlet surface, but the boundary formed by the filter and the box sealing surface.

Ai Li industrialThe HEPA and ULPA air filter pages list filter configuration instructions by grade. When confirming the filtration boundary, the equipment manufacturer can directly correspond to the model and check the grade, sealing and leak detection conditions together. Regarding the selection method of H13 filter, please refer toHow to choose H13 filter for EFU? efficiency, resistance, sealing and overall machine matching methods .Check points in

Cooperate with the fan: the filter resistance determines the fan working point

The function of the EFU filter is directly related to the fan operating point. The filter has resistance, and the fan needs to provide enough static pressure to overcome the resistance and deliver the target air volume to the protected area. As the filter level increases, the resistance increases, and the fan operating point shifts toward the direction of smaller air volume; the filter accumulates dust, the resistance increases, and the air volume decreases. The filter and fan are in a cooperative relationship and are not independent components. Only confirm the filter level and not the fan residual pressure. The air volume may be insufficient after installation.

Regarding the relationship between the initial resistance of the filter and the matching of the fan, please refer toHow to confirm the initial resistance of EFU filter? rated air volume, test conditions and fan matching . Verification steps for For the analysis method of fan operating point, please refer toHow to choose EFU centrifugal fan? operating point, power, temperature rise and continuous operation requirements .Description of

Cooperate with the box: the sealing structure determines the risk of bypass

The function of the EFU filter also depends on its cooperation with the cabinet. The sealing structure between the filter and the box determines whether there is a bypass of unfiltered air. Uneven sealing surface, uneven pressing, and frame deformation may cause bypass. When bypass exists, no matter how high the filter level is, the actual protection effect will be reduced. The cooperation between the filter and the box is a key link in whether the filter can play its role.

Regarding the relationship between sealing structure and complete machine sealing, please refer toHow to confirm EFU installation seal? equipment drawings, installation conditions and acceptance methods .Verification methods in

Use boundaries: Which issues are outside the scope of the filter

Understand what the EFU filter does and what problems are not within the scope of the filter. The overall cleanliness level of the equipment, pollutants taken away by the process exhaust, the external environment of the equipment, particles brought in by personnel operations, and the pollution of the air supply path after the filter cannot be solved by filters alone. The filter is responsible for intercepting particles in the air that pass through it. The cleaning of the path after the filter, the overall airflow organization of the equipment, and the control of external pollution sources require the cooperation of the equipment designer and the system solution.

For the relationship between airflow boundary and protection effect, please refer toWhy does the same air volume produce different cleaning and protection effects? In the instructions, consider the filter's range of action together with the airflow conditions inside the equipment.

Applicable scenarios: Different devices have different requirements for filters

The scope of the EFU filter changes with the device scenario. Semiconductor front-end equipment focuses on particle control of the wafer path, lithography equipment focuses on the cleanliness of the optical path, etching equipment also considers the impact of corrosive gases on filters, and SMT placement machines focus on the protection of the mounting area. Different equipment has different requirements for filter grade, sealing and material. When selecting, first clarify the equipment scene and protection area, and then determine the filter grade, structure and sealing method.

For EFU configuration methods of different devices, please refer toHow to configure the semiconductor front-end equipment EFU? the key points of clean areas, air volume filtration and equipment interfaces . Area division and interface confirmation ideas in For corrosion environment coordination of etching equipment, please refer toHow to configure the etching equipment EFU? how to coordinate clean air supply, process exhaust and corrosive environment .Explain

Aili Industrial's EFU filter package

Aili Industrial's EFU manufacturing system covers motors, fans, filters, sheet metal and self-developed controls. The efficiency, resistance, sealing and working point of the whole machine of the filter can be checked according to the equipment drawings in the same manufacturing system. The size of the filter, the structure of the box and the interface of the whole machine do not need to be transferred between multiple suppliers. For equipment with clear requirements for filters, Aili Industrial can organize prototype verification and batch curing according to the confirmation drawing, and put the filtration grade, sealing structure and leak detection requirements 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 filtration level, filtration boundary, sealing structure, fan coordination and usage boundary to the supplementary list, and then organize the comparison after the supplier responds. The confirmed filter model, 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 filter, fan and box correspond one by one according to the order list, which facilitates the equipment manufacturer to place the role of the filter on the verifiable complete machine conditions.

Misunderstandings to avoid

It should be avoided to equate the filter with the overall cleanliness plan of the equipment. It should be avoided to only confirm the filter grade but not the sealing status. It should be avoided to ignore the working point cooperation between the filter and the fan. It should be avoided to ignore the path pollution after the filter. It should be avoided to blame the external pollution problem of the equipment on the filter head. The role of the EFU filter is local and has boundaries. Only by drawing the boundaries clearly can the selection and acceptance be based on it. Aili Industrial can first form a to-be-confirmed list according to the equipment drawings, listing the filtration level, sealing and boundary conditions together.

Related questions and answers

Is the higher the filtration efficiency level more suitable for EFU?

uncertain. Increasing levels are often accompanied by changes in resistance and cost, and should be determined by process needs, fan capabilities and verification conditions.

How to promote EFU filter selection 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 filtration level, sealing and boundary conditions together.

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

Prepare current project information around functional boundaries, rated operating conditions and equipment interfaces. 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 understanding the function of the EFU filter, you can refer to the complete machine and filter supporting instructions provided by Aili Industry by model.

Related articles

What is EFU? Structure, function, working principle and applicable equipment description

What is the function of device-side EFU? Position and usage boundaries of equipment-side clean air supply

How to choose H13 filter for EFU? Efficiency, resistance, sealing and complete machine matching methods

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 efficiency, resistance, sealing and working point of the whole machine of the filter can be checked according to the equipment drawings in the same manufacturing system. The size of the filter, the structure of the box and the interface of the whole machine do not need to be transferred between multiple suppliers. The equipment factory completes filter selection 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 , 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.