Helios Fans RDD 250/4 Ex

The Helios RDD 250/4 Ex is a powerful explosion-proof horizontal roof fan engineered for industrial applications where ATEX compliance is essential. Designed to safely ventilate hazardous environments, this unit offers a high level of performance and durability.

Its housing is made of seawater-resistant aluminum, providing long-lasting corrosion resistance and built-in intrusion protection. The fan includes a galvanized steel engine support plate and base plate, complemented by an aluminum inlet nozzle. The base is pre-fitted with a threaded screw and a standardized hole pattern (DIN 24155, sheet 3) to allow easy mounting of suction-side accessories. A discharge-side safety grille is included in accordance with DIN EN ISO 13857.

The RDD 250/4 Ex features a newly designed radial impeller with backward-curved aluminum blades, dynamically balanced according to DIN ISO 1940 – 1 for smooth, vibration-free operation. It is powered by a three-phase external rotor motor in a closed IP44-rated housing, protected against moisture and dust. The motor is speed-controllable, maintenance-free, and fitted with ball bearings for reliable continuous use. Its explosion-proof design ensures safe performance in ATEX-classified zones.