Improvement in the ventilation arrangement of a fume extraction hood

A fume extractor hood comprising, an upper planar horizontal member adapted to capture and collect vapours and gases flowing up from a cooktop lying therebelow, where the vapours and fumes to be extracted are generated, a suction conduit that is open in the middle region of the upper planar horizontal member, first suction means associated to the suction conduit and adapted to suck in the fumes and vapours therefrom and blow them outside, wherein such means comprise a suction fan associated to the conduit, ventilation means adapted to impart a whirling motion about a vertical axis (X) to the mixture of air and other gases contained in the volume below the upper planar horizontal member. The ventilation means comprises: an internally hollow cylindrical member, a peripheral edge of which is placed onto the outer edge of the upper planar horizontal member, and which extends vertically downwards from the upper planar horizontal member without reaching the level of the cooktop or simuilar surface lying therebelow. The ventilation means also comprises a plurality of outflow channels distributed over the internal cylindrical wall of the cylindrical member, these outflow channels being oriented vertically and being each provided with at least one outflow port. The cylindrical member has a substantially octagonal shape, and each of the outflow channels is positioned in correspondence to a respective corner of the cylindrical member.