Mouth of a hood for sucking up fine particles, and laser device for ablating a surface layer of a wall comprising such a hood

A hood for sucking up fine particles, comprising

• an air intake mouth comprising a crest intended to be arranged close to a wall able to emit fine particles, the crest defining an internal portion of the hood and an external portion;
• and
• a suction outlet intended to suck up the fine particles;
• wherein the mouth further comprises an external lip extending towards the suction outlet and comprising a leading edge located on the same side as the outlet in relation to the crest, in such a way that, when the hood is in operation, the sucked-up air undergoes no separation at the lip and that an air separation zone is located only in the internal portion of the hood and in that the mouth further comprises an internal shoulder able to form a vortex trap beyond the crest in the separation zone, in such a way that, when the hood is in operation, the vortices remain inside the hood in relation to the wall.