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Blauberg Box-FI 50x25 4D

Centrifugal fans in sound-insulated casing for rectangular ducts. Maximum air flow up to 1850 m³/h.
EAN codeEAN4058448055812
  • Description
  • Characteristics
  • Capacity diagram
  • Downloads
  • Designation key
  • Dimensions
  • Additional characteristics
  • Accessories

Supply and extract ventilation systems installed in various premises. Compatible with 400x200 up to 1000x500 mm rectangular air ducts.


Atmospheric resistant galvanized steel casing and impeller. The casing is heat- and sound-insulated with 50 mm mineral wool. The fan is rated for continuous operation. Fitted with standard 20 mm connecting flanges for connection to rectangular air ducts. Access cover on the casing for inspection and maintenance operations.


The fan is designed for mounting inside rectangular air ducts and can be installed in any position. The fan flanges are connected to the air ducts through the bolts inserted into the flange holes. Mounting to a round air duct on exhaust flange through a round pipe reducer. Available upon order. If flexible vibration-absorbing connectors are used to connect the fan to the air ducts provide their fixation to mounting structures with supports or brackets. While mounting provide enough space for accessing the cover for service operations.


Four- or six-pole asynchronous motor with external rotor and centrifugal impeller with forward curved blades. Due to its impeller design the fan has excellent air dynamic charakteristics (high performance and pressure drop).Single-phase (E) or three-phase (D) motor modifications.Equipped with ball bearings for longer service life.Dynamically balanced impeller.Overheating protection by built-in thermal switches with leaded outside terminals for connection to external protecting controls.The thermal switch terminal leads are designed for connection to respective circuit ot the overload relay or respective terminals of the autotransformer or thyristor speed controller.

Speed control

Smooth speed control with an external thyristor controller or step speed control with an external auto transformer (both available upon separate order).

Parameter Box-FI 50x25 4D Measurement unit
Voltage 400 V
Phase 3 ˜
Frequency 50 Hz
Power 570 W
Current 0.94 A
RPM 1270 min-1
Maximum air flow 514 l/s
Maximum air flow 1850 m³/h
Sound pressure level at 3 m 44 dBА
Transported air temperature -20...+40 °С
Motor IP rating IP44 -
Ingress protection rating IPX4 -
EC motor no -
Weight 40.5 kg
Width 500 mm
Height 250 mm
Casing material galvanized steel -
Outdoor mounting no -
Sound-insulated casing yes -
Air duct for rectangular air ducts -
Design centrifugal -
Type Exhaust, Supply -
Mounting Inline -
ErP 2018 -
Capacity diagram
Capacity diagram
  • Selection method:
  • Air capacity:
  • Pressure:
Operating point
  • Air capacity: --
  • Pressure: ---
Documents archieve
Documents archieve
Select a document type
  • Catalogues
  • Technical documentation
  • Certificates
Box - user's manual (pdf 3.76Mb)
Box-FI - data sheet (pdf 1.17Mb)
Box-FI - image (png 616.3Kb)
Designation key
Designation key
Series Flange size (width x height) [cm] Motor
Number of poles
Box-FI 40x20; 50x25; 50x30; 60x30; 60x35; 70x40; 80x50; 90x50; 100x50 4; 6 E: single-phase
D: three-phase

Model Overall dimensions [mm]
B B1 B2 B3 H H1 H2 H3 L
Box-FI 50x25 4D 500 520 540 570 250 270 290 410 640
Additional characteristics
Additional characteristics
Sound power level, A-weighted Octave frequency bands [Hz] LpA 3 m [dBA] LpA 1 m [dBA]
Total 63 125 250 500 1000 2000 4000 8000
LwA to inlet [dBA] 80 68 75 72 69 72 70 68 65 59 69
LwA to outlet [dBA] 83 63 72 72 74 76 76 75 70 62 72
LwA to environment [dBA] 65 43 51 56 56 60 55 54 56 44 54
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