The Helios HRFD 250/4 Ex is an explosion-proof axial duct fan designed for use in hazardous environments, certified according to ATEX standards. It features a sturdy cylindrical duct made of galvanised sheet steel with flanges on both ends for secure installation, meeting DIN 24155 dimensional and flange hole specifications.
This model is equipped with a highly efficient, 7‑blade profiled impeller manufactured from impact-resistant, anti-static polymers, dynamically balanced to DIN ISO 1940 and VDI 2060 class 6.3 standards. It operates safely within a temperature range of ‑30 °C to +40 °C and has an electrical resistance below 1 Ohm to minimize static buildup.
The fan is powered by a totally enclosed, maintenance-free 3‑phase squirrel cage motor with sealed-for-life ball bearings, delivering quiet operation. Note that this motor is not speed controllable. The explosion-proof construction ensures safe performance in industrial settings where hazardous atmospheres are present.