Patent ID: 8153058

Claim:
A device for the treatment of a liquid or gaseous medium using UV radiation, said device comprising, in combination: (a) an elongate UV radiation source arranged in an axial longitudinal direction and providing radiation (R) with a wavelength in the at least one of the UVC and UV range in a substantially radial direction of irradiation; (b) a plurality of layers of transmissive treatment chambers (K 1 -K 4 ), serially arranged one on the other in the radiation direction (R); (c) a plurality of transmissive separating layers (T 1 -T 4 ) that separate the UV-transmissive treatment chambers (K 1 -K 4 ) from each other; (d) an upper cover and a lower cover, between which are located the UV radiation source and the separating layers (T 1 -T 4 ); and (e) an exposure time prolongation device, at least a portion (D 1 -D 3 ) of which is located in at least one of said upper and lower covers; wherein, beginning with a first treatment chamber (K 1 ) adjacent to the UV radiation source, said chambers form a flow channel for the medium running in the longitudinal direction of the UV radiation source, said flow channel emptying into the subsequent treatment chamber (K 2 , K 3 , K 4 ) further from the UV radiation source in the direction of irradiation (R); and wherein a portion of the exposure time prolongation device that is located in at least one of the covers includes a turbulence device (D 1 -D 3 ) for the medium to be treated.