US Patent 10507342 Fire-fight ventilator with ovalised air jet

A fire fighting blower (1) comprises a propeller (2) coaxially mounted in a tubular casing (3) for generating an axial airflow. The blower comprises an airflow guiding device (9) in the casing (3) for obtaining a concentrated air jet having a substantially ovalized section, it comprises within the tubular casing (3) an assembly of first deflectors (4) for concentrating the axial airflow and generating a concentrated axial air jet and an assembly of second deflectors (16, 17) for generating an air stream deflected from the concentrated axial air jet so that the concentrated air jet having an ovalized section is a combination of the concentrated axial air jet and the deflected air stream.