Number of views: 5491 Author: Aili Industry Release time: 2026-09-28 Source: Ai Li Industrial
Fan box selection is not about picking a model with the largest 'maximum air volume', but first matching the design air volume and its corresponding external static pressure into a set of working points, and then checking the input power, noise, size, power supply, control interface and maintenance conditions of the whole machine. Looking at air volume alone, static pressure alone, and motor power alone cannot determine how the equipment will operate after it is installed in the system.
The air volume must correspond to a certain external static pressure. The nominal maximum air volume is often obtained under specific test conditions and does not necessarily correspond to the actual resistance of the project. The same fan box may send out a larger air volume when a short air duct is connected. After a filter section and a long air duct are connected, the air volume will be significantly reduced. The selection table should contain at least three parameters: 'air volume, external static pressure, and machine input power' at the same time. If necessary, a performance curve should also be provided.
The nominal maximum air volume and maximum static pressure are usually not at the same operating point. Putting the two maximum values together as project requirements will cause misjudgment in selection. The correct approach is to find the intersection point of the design air volume and external static pressure on the performance curve, confirm that this intersection falls near the fan's high efficiency area, and leave an adjustment margin to deal with the increase in resistance such as dust accumulation on the filter.
The noise value should also describe the measurement distance and operating conditions. The noise measured 1 meter away from the unit cannot be directly compared with the value measured 3 meters away. At different speeds, the noise will also change. When selecting, the supplier should be asked to indicate the test conditions instead of just giving a decibel number.
The external resistance that the fan box needs to overcome comes from multiple links: filter section, coil, air valve, muffler, elbow, reducer, straight section of the air duct and the most unfavorable branch. Each of these consumes the pressure provided by the blower. If you only estimate based on the length of the straight pipe and ignore local components and filter sections, the selected fan may have insufficient air flow in the actual system.
When the cleaning or air conditioning system has a filter section, the cleaning status and the allowable pressure difference before maintenance should be understood separately. If the fan is selected only according to the clean filter status, the equipment may not be able to meet the terminal air volume after running for a period of time. The margin cannot be increased indefinitely, otherwise daily operation may require throttling for a long time, resulting in unnecessary energy consumption.
If the end of the system adoptsFor HEPA/ULPA high-efficiency filters , the initial resistance and resistance after use of the filter should be included in the total resistance of the system, and the replacement conditions should be written into the calculation boundary. When the process requirements are higher, it can also be evaluatedDoes the ULPA ultra-high efficiency filter meet the requirements?
After obtaining the supplier's information, you can mark the design air volume and external static pressure as a point on the same performance curve and observe three things: whether this point falls in the high-efficiency area of the fan; whether there is an operable range nearby that can meet the change in filter resistance; whether the shaft power, machine input power and noise conditions corresponding to the point are within the allowable range of the project.
Then check the drawing interface and electrical point table. The direction of the air outlet, flange size, foundation hole position, box weight, access door direction, power supply voltage, and control signal type should be consistent with the site conditions. Of two fan cases with the same performance, only one may be truly suitable for the existing computer room. If the project adopts a DC speed regulation solution, it is also necessary to confirm the driver installation location, heat dissipation conditions and speed regulation signal type.
Many selection errors are not due to miscalculation of performance, but due to mismatched interfaces. Just because the equipment can be placed in the computer room does not mean that it can be maintained; if the performance is up to standard, it does not mean that the control cabinet can be wired. The selection stage should also confirm: the direction and size of the air inlet and outlet, flange specifications, vibration reduction requirements, maintenance space, hoisting path, power supply conditions, speed control interface and fault feedback method.
Promote selection based on the working point table, on-site installation diagram and control point table, so that the drawings, quotations and acceptance data can correspond to the same set of conditions. Aili Industrial has supporting capabilities in fans, motors, controls and sheet metal structures, and can check the parameters of the entire machine according to project working conditions, reducing on-site modifications caused by interface inconsistencies. Specific configuration options can be found inIt is confirmed in the fan box product catalog that non-standard projects should provide equipment or machine room drawings, and then shape them based on the determined working points and on-site interfaces.
The blower box is responsible for providing the power, and the filtration task is usually performed by a separate device. Clean room ceiling air supply is comparableFFU fan filter unit ; centralized management of multiple devices can be matchedThe FFU computer group control system realizes zone speed regulation and status monitoring. Protection of single process equipment can be consideredEquipment-side fan filter unit (EFU) . The final filtered air supply at the end of the air duct can beHigh-efficiency air supply outlet (HEPA BOX) . The division of labor boundaries between these equipment and the fan box should be clearly drawn on the system flow chart to avoid confusing power equipment and filtering equipment.
