The invention relates to a device for irradiating an absorbing liquid, forexample waste water to be disinfected, in a throughflow. Said device comprisesat least two radiator units having one cylindrical UV radiation source (4) andthree concentric sheaths (1, 2, 3). A cooling medium for carrying off heatfrom the UV radiation source flows in a hollow space between the inner (3) andthe center (2) sheath. The inventive device allows to use high-performance UVradiation sources and to evenly irradiate the zones of irradiation andprevents floating particles from settling down on the radiator units.
