DFX ventilation fan boxes deliver scheduled air volume quietly and reliably after duct resistance is added, combining compact direct-drive or flexible belt-drive arrangements with double-skin acoustic insulation.
Compare YONGFAN DFX-I external-rotor direct-drive units (DFX-I-10 to 18) and DFX high-capacity belt-drive configurations (DFX-I-10 to 40) across airflow (800 to 171,000 m³/h), total pressure (190 to 1,460 Pa), and building applications from hotels and offices to schools and industrial workshops.
A fan box moves air strictly at the intersection of its fan curve and total system resistance. Long duct runs, elbows, volume control dampers, grilles, and diffusers all consume static pressure.
Inlet and outlet duct connections also introduce aerodynamic losses. [ISO 5801](https://www.iso.org/standard/56517.html) defines laboratory test airways, while [ISO/TR 16219:2024](https://www.iso.org/standard/87617.html) addresses system effect penalties caused by poor field installations.
Resolving airflow, total pressure, drive type (direct vs belt), and service access clearance together guarantees trouble-free handover.
DFX sizing accounts for external duct static loss and internal cabinet losses to ensure target CFM delivery on site.
Direct drive external-rotor motors eliminate belt wear for tight spaces; belt-drive units allow site speed optimization up to 171,000 m³/h.
Hinged quick-release access panels require adequate side clearance for motor inspection and bearing lubrication.
DFX-I-10 to DFX-I-18 direct-drive units with double-skin acoustic lining provide quiet continuous air exchange for guest rooms, luxury apartments, and corridor extract.
Medium-capacity belt-drive DFX cabinets with forward-curved double-inlet centrifugal wheels, delivering high airflow with low NC noise ratings in ceiling voids.
DFX units configured for large occupant loads, providing continuous fresh air ventilation with VFD speed modulation and motorized shutoff dampers.
Large belt-drive DFX cabinets up to 171,000 m³/h and 1,460 Pa for factory warehouse ventilation, machinery room heat removal, and process exhaust.
| DFX Variant | Documented Size Range | Airflow Boundary Range | Total Pressure Boundary | Primary Engineering Advantage | Action |
|---|---|---|---|---|---|
DFX-I External-Rotor Direct-Drive |
DFX-I-10, 12, 15, 18 | 800 – 18,500 m³/h |
190 – 820 Pa ΔPt |
Compact cabinet depth; zero belt maintenance; quiet external-rotor motor | Configure Direct |
DFX Heavy-Duty Belt-Drive |
DFX-I-10 through DFX-I-40 | 2,500 – 171,000 m³/h |
240 – 1,460 Pa ΔPt |
High airflow and higher pressure capability; flexible pulley speed matching | Configure Belt |
DFX cabinets offer flexible inlet/outlet configurations (in-line straight, side inlet, top discharge). Confirm overall length, width, and height against structural ceiling hangers and duct connections.
Flexible canvas/neoprene duct connectors and internal spring isolators isolate vibration and simplify connection alignment.
Do not select DFX at the extreme cutoff point of its airflow table. Ensure the design duty sits within the stable central portion of the pressure-volume curve with at least a 10–15% pressure margin for duct loading.
Motor power ratings should provide adequate safety factor to prevent thermal trip under cold startup air density conditions.
Submitting your duct layout, calculated static pressure loss, and available ceiling height enables our team to confirm direct vs belt drive and supply certified 3D CAD drawings.
Pentapost corner joiners and extruded aluminium framework eliminate cabinet vibration and ensure air-tight casing sealing.
Galvanized steel double-skin panels with high-density acoustic insulation drastically reduce sound transmission to occupied spaces.
Double-inlet forward-curved centrifugal impellers are dynamically balanced to ISO 1940 G2.5 on precision electronic balancing machines.
Every DFX fan box is tested for electrical motor current, vibration velocity, and bearing alignment prior to export packaging.
Direct-drive (DFX-I-10 to 18) uses external-rotor motors with zero belt maintenance and compact depth. Belt-drive (up to DFX-I-40) reaches higher airflows up to 171,000 m³/h with flexible speed matching.
DFX Belt-Drive Series reaches up to 171,000 m³/h and 1,460 Pa total pressure on larger cabinet frame sizes.
No. External duct static pressure must be calculated. Selecting a fan box on airflow alone can result in severe airflow reduction on site.
Yes. DFX panels feature double-skin construction packed with high-density acoustic mineral wool to minimize casing breakout noise.
DFX cabinets support in-line straight, side inlet, top discharge, and bottom discharge spigot orientations for flexible duct routing.
For multi-stage filtration, select DFX Purification Fan Boxes, which integrate primary G4, secondary F8, HEPA, and carbon modules.
Standard DFX is for normal ventilation. For 280 °C / 30 min emergency fire smoke duty, specify the HTFC Series.
Yes. YONGFAN manufactures BDFX / BHTFC explosion-proof fan boxes certified under GB 3836 for hazardous gas areas.
Send your required airflow, external duct resistance, acoustic limits, and space dimensions — our application engineers will confirm total pressure requirements and provide complete technical submittals.
