Backward Curved Centrifugal Fans

Backward Curved Centrifugal Fans are radial fans with blades bent back. They are characterized by extremely high available pressures and a compact design. The aerodynamic rotor geometry and the shape of blades combined with energy-efficient electronically commutated EC motors or high-efficiency AC induction motors provide very favorable operating parameters: high capacity, efficiency, and the ability to cope with high flow resistance.

Such fans are widely used in devices where there are high air flow resistances, where a compact design or smooth capacity regulation is required: recuperators, ventilation units, filtration devices, etc.

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-EC072-10013323050/604500550,436844B-25 ~ +60PA66350
B3P155-EC072-00115523050/603750400,36344B-25 ~ +60PA66450
B3P175-EC072-10017523050/603750800,657444B-25 ~ +60PA66650
B3P190-EC072-00219023050/603750950,737844B-25 ~ +60PA66750
B3P190-EC092-10019023050/60410015018044B-25 ~ +60PA66800
B3P220-EC072-10022023050/602500700,67144B-25 ~ +60PA66850
B3P220-EC092-10022023050/60331014517544B-25 ~ +60PA66980
B3P225-EC072-10022523050/602500800,66944B-25 ~ +60PA661100
B3P225-EC092-02222523050/6030001901,357944B-25 ~ +60PA661500
B3P250-EC072-00825023050/602150900,86844B-25 ~ +60PA661150
B3P250-EC092-02025023050/6026001701,16944B-25 ~ +60PA661350
B3P250-EC092-03325023050/60250014517444B-25 ~ +60aluminium1680
B3P250-EC102-00125023050/6031702701,28444-25 ~ +60aluminium1730
B3P280-EC092-00428023050/60232513517544B-25 ~ +60stal1530
B3P280-EC092-10028023050/6020001300,97344B-25 ~ +60stal1900
B3P280-EC137-1002803x40050/6028507801,18244F-25 ~ +60aluminium2980
B3P310-EC092-10031023050/6019251751,37444B-25 ~ +60aluminium2200
B3P310-EC092-00131023050/6017701751,37354B-25 ~ +60aluminium2450
B3P310-EC102-10031023050/6022503001,46854B-25 ~ +60aluminium2500
B3P310-EC102-00131023050/6022003201,456854B-25 ~ +60aluminium2750
B3P310-EC137-1003103x40050/6026009801,647444F-25 ~ +60aluminium4250
B3P355-EC092-00135523050/6014001200,96854B-25 ~ +60aluminium2480
B3P355-EC102-10035523050/6019003301,57754B-25 ~ +60aluminium3050
B3P355-EC102-00135523050/6017003101,47354B-25 ~ +60aluminium3050
B3P355-EC137-1003553x40050/6021009901,637944F-25 ~ +60aluminium5100
B3P400-EC102-10040023050/60140022017254B-25 ~ +60aluminium3500
B3P400-EC102-00140023050/6014303301,56954B-25 ~ +60aluminium3550
B3P400-EC137-1004003x40050/6015507251,227344F-25 ~ +60aluminium5400
B3P450-EC102-10045023050/6011002601,27044B-25 ~ +60aluminium4600
B3P450-EC137-1004503x40050/60145010001,677344B-25 ~ +60aluminium7400
B3P470-EC102-00247023050/6011001850,856942B-25 ~ +60stal4000
B3P470-EC102-00347023050/6011001850,856944B-25 ~ +60stal4000
B3P500-EC137-1005003x40050/6011008701,467144B-25 ~ +60aluminium7900
B3P560-EC137-1005603x40050/608507701,36944B-25 ~ +60aluminium9050

Plug fans are EC centrifugal fans with backwards curved blades that provide high compression and efficiency

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.

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.

A forward curved impeller usually has a more compact design but requires a spiral housing to generate static pressure.

  • 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

Compact plug fan EC 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