Backward Curved Centrifugal Fans +

Backward Curved Centrifugal Fans + are radial fans with blades bent back and equipped with a compact air flow module. They are characterised by extremely high available pressures and a compact design. The aerodynamic air intake cone is integrated into the rotor for maximum efficiency of the fan unit. Combined with energy-efficient, electronically commutated EC motors, they provide very favourable operating parameters: high performance, efficiency, as well as the ability to cope with high flow resistance.

Such a compact design significantly speeds up installing the fan in the device. Thanks to the factory-integrated cone and fan, there is no need to position the entire system. Assembling the unit comes down to screwing in only 4 screws.

Technical data of the fans

Product codeDiameter [mm]Power [V]Frequency [Hz]Maximum rotational speed [min-1]Power [W]Electricity [A]Sound pressure level Lp [dB (A)]IPInsulation classWorking temperature range [oC]Rotor materialMaximum efficiency [m3/h]
B3P133-EC072-01013323050/604500550,436844B-25 ~ +60PA66330
B3P190-EC072-00519023050/603750950,737844B-25 ~ +60PA66750
B3P250-EC092-02525023050/6026001701,16944B-25 ~ +61PA661350
B3P280-EC092-01328023050/6020001300,97344B-25 ~ +62PA661900
B3P280-EC137-0102803x40050/6028507801,18544B-25 ~ +63PA662950
B3P310-EC092-01331023050/6017701751,37344B-25 ~ +64PA662400
B3P310-EC102-01331023050/6022003201,456844B-25 ~ +65PA662800
B3P310-EC137-0103103x40050/6026009801,647444B-25 ~ +66PA664250
B3P355-EC102-01335523050/6017003101,47344B-25 ~ +67PA661700
B3P355-EC137-0103553x40050/6021009901,637944B-25 ~ +68PA665050
B3P400-EC102-01340023050/6014303301,56944B-25 ~ +69PA663500
B3P400-EC137-0104003x40050/6015507251,227344B-25 ~ +70PA665400
B3P450-EC137-0104503x40050/60145010061,677344B-25 ~ +71PA667200
B3P500-EC137-0105003x40050/6011008701,467144B-25 ~ +72PA667900
B3P560-EC137-0105603x40050/608508501,36944B-25 ~ +73PA669000

Plug fan+ is an EC centrifugal fan with backward curved blades and mounting plate - high pressure, high efficiency, quick installation

Centrifugal fans with backward blades are compact industrial fans that are flexible in their use and provide high airflow capacity at high discharge pressure. Optimized design and high-efficiency, easy-to-regulate EC motors help to keep running costs low in the long term. They are appreciated by manufacturers of industrial solutions for their high efficiency and high available compression while maintaining low energy consumption. In addition, the fans in the plug fan+ version have a factory-integrated funnel and mounting plate to speed up installation.

The radial fans with backwards curved blades available from manufacturer AFL have been developed for both efficient and comfortable use. The range includes models that guarantee quiet and trouble-free operation and are made of high-quality components and assemblies. These parameters are just as relevant for commercial and industrial premises. The characteristics of the selected models are summarised in the graph below.

Operating principle of the radial fan with backward curved blades

In radial fans, the air is directed outwards from the impeller, perpendicular to the motor’s axis of rotation.

In addition, we can distinguish between different types of rotors, the two commonly used types being:

  • Forward curved blades
    The forward curved impeller has a greater number of shallow blades pointing in the direction of rotation and can have a single air inlet or a wider double inlet. A forward-bent impeller produces the same pressure as a backwards curved impeller at a much lower sp, and this makes such fans relatively quiet.
  • Backward curved blades - plug fan
    Backward curved impellers have a smaller number of longer blades facing away from the direction of rotation.
    Backward curved impellers require higher speeds than forward curved impellers but operate more efficiently due to the pressure generation mechanism. The advantage of this design is that it is less susceptible to motor overload.

EC centrifugal fans with backward curved blades - a wide range of applications

EC compact plug fans+ are used wherever a high airflow capacity is needed with high installation resistance. Tailored actuators and control technology ensure targeted airflow, whether in refrigeration, air conditioning, ventilation or renewable energy.


They are perfect for products such as air handling units, heat recovery units, air purifiers or roof fans. They are used in industrial ventilation applications where the ability to overcome system resistance is also needed in addition to high efficiency.

They are perfect for products such as air handling units, recuperators, air purifiers or roof fans. They are used in industrial ventilation applications where the ability to overcome system resistance is also needed in addition to high efficiency.

All AFL’s backward blade EC radial fans have been developed to meet the highest requirements. Their main advantages are:

  • Low operating costs due to high-efficiency ratio.
  • Outstanding flexibility due to fully adjustable air flow rate.
  • Compact dimensions for every type of installation.
  • Indywidualne rozwiązania specjalne, dopasowane do potrzeb klienta
  • Durability due to top-quality components and a controlled production process.
  • Compliance with European directives and standards, CE, RoHS, Reach, ErP certifications