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What Is Fan Filter Unit？

Views: 0 Author: Site Editor Publish Time: 2026-03-06 Origin: Site

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The performance of FFUs is heavily reliant on the internal fans. Cigeair utilizes top-quality domestic and international EC series DC fans as the core components of FFUs, ensuring stability and consistency of performance. The filters can be customized to utilize fiberglass filter paper or PTFE filter paper, which optimizes the filters’ initial resistance to meet customers' demands for ultra-low energy consumption.

As a high-tech enterprise in the field of purification equipment, Cigeair's FFUs have earned widespread recognition and application among customers. Cigeair has delivered comprehensive and high-quality cleanroom air purification solutions for numerous electronics and pharmaceutical companies.

FFU Structure and Classification：

FFU basic parameters

Noise levels for domestic brand FFUs generally range from 42 to 56 dBA. DC FFUs are typically quieter by about 1-3 dBA compared to AC FFUs of the same size and specifications.

Vibration

Generally less than 1.0mm/s

Face velocity

The common standard wind speed is 0.45 m/s, and the rest can be customized

Uniformity

Indicates the consistency of the FFU face velocity, which is determined by the design and manufacturing quality of the fan, filter, and diffuser.

External static pressure

Also known as residual pressure, this parameter is critical for the lifespan of the FFU and is closely related to the fan. Typically, an external static pressure of at least 90 Pa is required at a face velocity of 0.45 m/s.

Power consumption

AC systems typically range from 100-300 watts, while DC systems range from 50-220 watts. DC systems consume 30%-50% less power than AC systems.

Technical Features of Cigeair EC FFU

More energy-efficient

EC FFUs can save about 30%-40% energy compared to AC fan FFUs.

Quieter operation

EC FFUs are about 5 dBA quieter than AC fan FFUs.

Easier control

AC FFUs use a manual speed control system suitable for facilities with fewer than 200 FFUs. In contrast, EC FFUs are ideal for large cleanroom facilities, They employ intelligent control systems managed by computers for each FFU, resulting in improved efficiency and reduced maintenance costs.

As customer demands for energy efficiency, noise, and controllability of FFUs increase, the application of EC FFUs is becoming increasingly widespread. In the following section, we will introduce the performance and technical features of EC FFUs, focusing on the fan, filter, housing, and control system.

Technical advantages of EC FFU

Active PFC technology

EBM fans can save energy up to 33%, while passive filtering method can only save 4%.

Compensation principle

Active power filters generate harmonic currents with equal amplitude but opposite phase.

This ensures that the load current on the supply side is a sine wave.

Main hazards of harmonics

Harmonics can cause relay protection and safety automation devices to fail or malfunction.

They can trigger resonance phenomena, which may result in damage to capacitors and transformers due to overcurrent or overvoltage.

Harmonics increase the harmonic losses in power systems.

They diminish the efficiency of electrical equipment, causing devices like rotating motors, capacitors, transformers, and conductors (e.g., low-voltage neutral lines, cables, bus bars, etc.) to operate under overload conditions (heating, vibration, abnormal noise, etc.), thereby shortening their lifespan.

"Zero" current startup technology

Figure 1 depicts the startup current diagram of typical AC FFUs and some domestic DC FFUs. Within 2.5 seconds after startup, a significant inrush current is generated, which is usually 3.5 times of the running current. This surge exerts a considerable impact on the power grid and power switching system.

Cigeair PuriFan EC FFU adopts German EBM fan, incorporating a gradual current discharge function. Upon FFU startup, the current gradually increases over 12 seconds before reaching the running current level. This feature effectively safeguards the power grid and power switch systems.

200V-270V ultra-wide voltage design

After 2004, DC fans integrated rectification and communication modules within the fan, effectively becoming a single unit. This change introduced the wide voltage design concept.

Voltage fluctuations are common in large electronic factories, where the start and stop of large electrical equipment such as air conditioners, pumps, and boilers can cause voltage fluctuations. The 200-270V wide voltage range ensures stable operation of the fans despite grid voltage fluctuations.

3D impeller design

The company has always been a leader in the industry in terms of impeller design.

The 3D impeller is developed from a simple curved impeller with appropriate tilt and airflow analysis. The guide strips on the blades feature patented technology. The angle of tilt and the design of the guide strips are derived from extensive calculations and experiments.

Thanks to the 3D impeller, the fan achieves the required air volume at a lower speed, thereby effectively reducing noise.

Patented "soft" commutation technology, no commutation noise

The patented "soft" commutation technology eliminates commutation noise. DC motors belong to the category of brushless motors. All brushless DC motors have an electronic commutation circuit, which eliminates the noise caused by mechanical commutation.

On this basis, DC fans incorporate patented "soft" commutation technology, which stabilizes the current during each commutation, thereby eliminating fluctuations. Particularly at high speeds, this technology significantly reduces commutation noise.

The new magnet material produces a homogenous magnetic field with no ripples, thereby minimizing magnetic field resonance and noise.

Soft start and soft brake technology

The Cigeair EC FFU incorporates soft brake/start function. As shown in the figure, initially, the fan operates in reverse 970 rpm (250Pa off-board pressure). After power on, the fan initiates the soft brake program; after 4.2 seconds, it absorbs the reverse current and the speed drops to reverse 40 rpm, facilitating a soft landing of rotation speed. Subsequently, it transitions into the soft start program, and after 12.2s, the fan speed gradually increases to forward 1613 rpm and enters the normal operation.

Cigeair's Latest AXI-I Control System

1、The upgraded super gateway simplifies installation and is compatible with eLisa 7.

2、Independent internal data transmission improves feedback speed by over 20 times compared to the original gateway configuration.

Cigeair's Latest AXI-I Control System

Upgrade of Cigeair control system (improved communication speed)

Working principle of control system (taking one PC controlling 19840 FFUs as an example)

Every 6 seconds, 10 main gateways report data from one FFU communication interface, with 31 FFUs per interface. Consequently, the server receives data for 10X31=310 FFUs every 6 seconds. To receive data for 19,840 FFUs, it takes (19840/310)6=384 seconds.

Every 8 seconds, the server receives data from all super gateways. In this system, there are 80*248=19,840 FFUs, so the scanning period is 8 seconds, 48 times faster than the original system.

Communication architecture comparison

The two systems adjust the gateway architecture by replacing the original main and sub gateways with super gateways, and adjusting the number of gateways.

The super gateway is directly connected between the switch and the FFUs, eliminating the need for a sub gateway stage. The RS485 signal is directly converted to a high-speed TCP/IP signal.

Each FFU communication port on the super gateway scans independently, improving scanning speed compared to the sequential scanning of the original sub gateways.

The scanning speed of the original system's main gateway is directly related to the number of managed sub gateways. The more gateways, the longer the scanning period. The new structure's super gateway manages only 248 FFUs, thus maintaining a scanning period of 8 seconds regardless of the total number of FFUs in the system.

Latest FFU control system - Cigeair AIX software

Interface beautification

Convenient operation

Optional database and server

for easy management

Cigeair's Latest AXI-I Control System

Cigeair - Software interface

System management

System parameter User management User log Modify log Change password

Fan management

Fan position lock Fan error record Fan operation log Gateway status Search

Cigeair's Latest AXI-I Control System

Cigeair - Software interface

Cigeair AXI-I features

Cross-regional management of drawing method

Centralized display control of FFU parameters

Automatic reading of EC fan serial

number for easy maintenance

Cigeair AXI-I Latest Control System

Cigeair AXI-I features

FFU vector diagram code display, easy to find and use

Streaming live video surveillance

Cigeair AXI-I features

Cigeair FFU incorporates a pressure differential control unit, facilitating automatic FFU speed adjustment. This feature enables the FFU's air outlet speed to be automatically adjusted based on the aging of the HEPA filters. As a result, it ensures the FFU maintains its original operating condition and preserves the cleanliness level of the cleanroom. AIX-I is currently the only control software integrating this feature.

Selection of high-efficiency baffle-free

filter efficiency