How to choose ultra-thin EFU fan? Space, air volume, static pressure, heat dissipation and maintenance points

Fan selection for ultra-thin EFU is two different ways from standard EFU. The standard EFU box is thick enough to accommodate a conventional external rotor fan. When selecting, just check the operating point according to the air volume curve. The cabinet of the ultra-thin model is pressed to 70mm or even thinner, and a conventional fan cannot be inserted into it, so only a flat brushless motor and compact impeller can be used. After the fan is thinned, the air volume and static pressure characteristics, heat dissipation conditions and maintenance methods must be rechecked. Choosing an ultra-thin EFU fan is not about 'finding a thin fan to install in', but confirming whether the fan can still deliver wind to the target working point in a restricted space. Aili Industrial's 70mm ultra-thin EFU uses a self-developed flat brushless motor and a dynamically balanced aluminum alloy wind wheel. The fan, box and filter are matched in the same manufacturing system.

Space: first look at the net height, and then look at how much the fan occupies

There are two levels of spatial constraints for ultra-thin EFU. The first layer is the total clear height left for the EFU by the equipment, and the second layer is the space left for the fan inside the EFU. The installation space of the EFU on the equipment side is usually between 100-150mm. The cabinet thickness of the 70mm ultra-thin model is 70mm, and the total thickness after including the filter is about 100mm. This total thickness determines whether the equipment interlayer can be installed.

But what matters when selecting a fan is not the thickness of the box shell, but the height occupied by the fan body inside the box . The thickness of the motor of conventional external rotor fans often exceeds 50mm, and there is almost no margin for the impeller and airflow channel when placed in a 70mm box. The flat brushless motor reduces the thickness of the motor to about 28mm, leaving space for the installation of the impeller and the passage of airflow. When selecting, the supplier should be asked to specify the height of the fan body and the diameter of the impeller, rather than just giving a box size. If the supplier only writes '70mm cabinet' but does not explain how much the fan occupies, the air duct may have been squeezed by the motor and become shapeless after being installed. Regarding the impact of the internal structure of the box on air flow, please refer toHow to design ultra-thin EFU air duct? compact structure, airflow organization and prototype verification .Description of inlet flow guidance and internal flow equalization in

Air volume and static pressure: Thin fan does not mean low static pressure, but it depends on how the curve goes.

The most common mistake to make when selecting an ultra-thin EFU fan is to only look at the rated air volume. The sample says 800 m³/h, but the actual air supply after being installed in the equipment may only be 600 m³/h - because there is back pressure inside the equipment, there is resistance in the filter, and there are turns in the air duct. Ultra-slim models have tight internal spaces and short airflow paths, and system resistance is often higher than during open bench testing.

What you need to look at when selecting a model is the static pressure margin under the target air volume . The air volume range of Aili Industrial's 70mm ultra-thin EFU is 200-800 m³/h, and the surface wind speed is adjustable from 0.35-0.45 m/s. But when it comes to a specific piece of equipment, what needs to be confirmed is: under the conditions of internal back pressure of the equipment (including filter final resistance, air duct resistance, and air outlet blockage), whether the fan's working point still falls in the high-efficiency zone. If the fan curve is close to the stall zone near the target air volume, the air volume will become unstable, and the wind speed fluctuation will directly affect the cleanliness. For the reading of fan operating point, please refer toHow to view the EFU fan performance curve? air volume, static pressure, power and operating point .Description of

Another point that is easily overlooked is the relationship between the air volume coverage of the ultra-slim model and the size of the impeller . Under the same box thickness, the larger the impeller diameter, the higher the air volume and static pressure at the same speed. However, the diameter of the impeller is limited by the length and width of the box. If the length and width of the non-standard size EFU are reduced too small, the diameter of the impeller will be reduced, and the air volume capacity will be reduced. When selecting a model, the length and width of the cabinet and the air volume requirements should be checked together instead of determining the size first and then requiring the air volume.

Heat dissipation: the fan itself is the heat source

The heat dissipation issue of ultra-thin EFU must be considered during the fan selection stage. The standard EFU box has a large space, and the motor heat has enough area to dissipate through the box wall; the ultra-thin model has a thin box and tight internal space, and the motor and control board are squeezed into a limited volume, making it easier for heat to accumulate. Although flat brushless motors are more efficient, the windings and bearings will still generate heat during continuous operation. If there is no reasonable air flow path in the box to take away the heat, the temperature rise will gradually increase, affecting the motor life and speed stability.

When selecting a fan, you need to confirm two things: the temperature rise characteristics of the fan itself (whether the supplier provides data on the motor housing temperature or winding temperature under continuous operation), and whether there is cooling airflow passing through the motor in the box . In ultra-thin cabinets, the airflow used to cool the motor and the air supply airflow sent to the filter often share the same channel. When selecting, make sure that the cooling path is not overcrowded. If the EFU is installed in a closed cavity of the equipment, the inlet air temperature itself may be higher than the ambient temperature of the workshop. The temperature rise check when selecting the fan should use the actual inlet air temperature in the equipment rather than the open bench data. For the verification method of temperature rise during continuous operation, please refer toHow to deal with ultra-thin EFU heat dissipation? source of temperature rise, air path coordination and long-term operation verification .Recording requirements for

Maintenance: How to replace the fan if it is broken, how to pump the filter

Fan maintenance for ultra-thin EFU needs to be thought through clearly during the selection stage. The equipment-side EFU is installed inside the machine, and the surrounding space is limited. If the fan or filter needs to be replaced, whether the operating space is sufficient or whether the equipment sheet metal needs to be removed will directly affect the downtime.

When selecting the model, you should confirm the installation method of the fan : whether it is an independent module pulled out from one side of the box, or whether it is integrated with the box structure and requires disassembly of the entire unit. The ultra-thin models are compact inside. Some designs stack the fan and filter together, so there is no need to move the fan when changing the filter; some designs require the fan to be removed before the filter can be taken out. When purchasing, the supplier should be asked to provide maintenance path instructions, or refer toHow to confirm the mounting hole position of customized EFU? Regarding the ideas for inspection of fixing and sealing surfaces in datum, tolerance, fixing and sealing surface inspection, check the maintenance space as part of the confirmation diagram. For the filter replacement direction and extraction space, please refer toHow to choose EFU filter without partition? Efficiency, Resistance, Sealing and Complete Machine Matching Methods .Complete machine matching instructions in

Aili Industrial's 70mm ultra-thin EFU supports the customization of the side air inlet/side air outlet structure and the flange interface is directly connected to the equipment air duct. The assembly relationship between the fan and the box is marked in the confirmation diagram, which facilitates the equipment manufacturer to check the maintenance space during the selection stage.

How to generate executable turbine verification results

First confirm the clear height of the equipment installation space, the length and width restrictions of the EFU box and the target air volume, and then ask the supplier to provide the air volume-static pressure operating point under back pressure conditions in the equipment , the height of the fan body, continuous operation temperature rise data and maintenance path instructions. Include the fan type, impeller size, heat dissipation conditions and replacement methods in the supplementary list. The confirmed fan configuration corresponds to the BOM of the complete machine, and open bench ratings cannot be used to replace the actual operating conditions within the equipment. Aili Industrial's EFU manufacturing system covers motors, fans, filters and complete machine assemblies. Fan matching for ultra-thin models can be checked against equipment drawings in the same system. The air volume, temperature rise and maintenance space data at the prototype stage are archived together with the confirmation drawings.

Misunderstandings to avoid

It should be avoided to only look at the thickness of the box without looking at the height of the fan body. It should be avoided to use the rated air volume of the sample to replace the air volume under back pressure conditions in the equipment. It should be avoided to ignore the independence of the motor heat dissipation path in the ultra-thin box. It should be avoided to avoid not confirming the operation space for filter replacement and fan maintenance during the selection stage. The core of ultra-thin EFU fan selection is not 'finding the thinnest fan', but the four conditions of space, air volume, static pressure, heat dissipation and maintenance form a verifiable working point in the actual installation environment of the equipment.

Related questions and answers

Is the thinner the ultra-thin EFU fan, the better?
no. After the thickness of the fan is compressed to a certain extent, the impeller diameter and airflow channel will be restricted, and the air volume and static pressure capacity will decrease. What should be looked at when selecting a model is 'within the allowable thickness of the box, whether the fan can provide sufficient static pressure at the target air volume', rather than simply comparing the thickness of the motor. The 70mm cabinet is paired with a flat motor of about 28mm, which is a balance between space and performance.

The air volume on the fan sample is 800, but the air volume installed in the equipment is only 500. Is this normal?
Depends on equipment internal back pressure and filter resistance. The sample air volume is usually the value under the condition of open bench, without filter or with primary resistance filter. The EFU in the equipment faces the final resistance filter, the air duct turns and the air outlet surface is blocked. The system resistance is higher and the actual air volume decreases is a normal phenomenon. When selecting, the supplier should be asked to provide air volume data including target filters and equipment back pressure.

The fan of the ultra-thin EFU is broken. Can I just replace the fan without replacing the whole machine?
Depends on the design. The fans of some ultra-thin models are independent modules that can be removed and replaced from one side of the box; the fans of some models are integrated with the box structure and need to be returned to the factory or replaced as a whole. When selecting the model, you should confirm the maintenance method, and write the replacement space and operation steps into the confirmation diagram to avoid finding that it cannot be removed until a fault occurs.

Related articles

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How to deal with ultra-thin EFU heat dissipation? Source of temperature rise, air path coordination and long-term operation verification

How to view the EFU fan performance curve? Air volume, static pressure, power and working point

Key points for selection and acceptance inspection

Aili Industrial EFU selection and procurement support

Aili Industrial's 70mm ultra-thin EFU uses a self-developed flat brushless motor and a high-precision dynamically balanced aluminum alloy wind wheel. The air volume is 200-800 m³/h, the surface wind speed is adjustable from 0.35-0.45 m/s, and it supports H13/H14 to U15/U16 filtration levels and RS485/Modbus control. For ultra-thin models, the fan working point, internal heat dissipation path and maintenance space of the box can be checked according to the equipment drawings, and the prototype data and confirmation drawings are filed together.

Learn about Aili Industrial EFU products and customized configurations. Check out the compact models.70mm ultra-thin EFU , the entire machine 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 clear height of the equipment installation space, target air volume, internal back pressure conditions and estimated quantity to facilitate confirmation of fan model and complete machine configuration.