Filtering device for dust and other pollutants

A device for filtering dust particles or other polluting agents in an air flow, said device comprising a spiral duct which extends in the form of superimposed volutes around a vertical generatrix (X), said duct extending between an inlet mouth and an outlet mouth for said air flow, said device wherein each volute of said duct has a cross-section with a larger dimension (y), measured along an axis (Y) perpendicular to said generatrix (X), at least five times greater than a smaller dimension (x), measured with respect to said generatrix, so as to obtain in zones of said duct a vacuum effect such as to separate and remove the dust particles or other polluting agents from said air flow and convey the finer dust particles in the direction of the generatrix (X).