Device for the generation of ultrasonic waves

This device comprises at least one piezoelectric or magnetostrictive ultrasonic converter (11), a main acoustic waveguide chamber (12), an intermediate acoustic waveguide chamber (13) and a tubular waveguide (14) associated with said chambers. Said waveguide (14) comprises an open or closed tubular body of circular or polygonal cross-section constituting a waveguide. The tube is closed at its upstream end by a base defining a first mechanical filter (15) and, at its downstream end, has an annular thickening (16) lying outside the tube and defining a second mechanical filter (17). The interior of the tube defines an acoustic chamber (18). The two filters (15, 17) are used to filter the vibrations of at least one range of given frequencies.