VM and VVSM fans are indispensable for both metallurgical enterprises and other industries where the transported air contains dust and other solid particles. Mill fans are usually installed after cyclones, separators, or similar equipment. The dust content in the airflow of such fans can be up to 80 g/m³ of coal or other dust. This is achieved by manufacturing a special impeller designed to operate with highly dust-laden air mixtures. Dust particles entering the airflow must not differ in size (fraction) or adhesion properties from coal dust. The maximum allowable temperature of the air transported by mill fans is +200°C.