Abstract: 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.

Abstract: The invention relates to a fluid premixer for mixing a first fluid and a second fluid by aspirating the second fluid into the first fluid by Venturi effect. The premixer comprises a pipe which has a first inlet for the first fluid at a first pressure and a second inlet for the second fluid to be mixed into the first fluid to form a mixture. The pipe also has an outlet for the mixture at a second pressure and a shutter movable between several positions where each position defines a distinct degree of shutting of the pipe. The premixer also includes a control element to control the position of the shutter as a function of the difference between the first pressure and the second pressure.