Patent ID: 8293185

Claim:
An ultraviolet irradiation apparatus comprising: a conduit having a central axis and adapted to conduct a fluid through its interior along its length from an inlet port to an outlet port downstream of the inlet port; an array of static mixer elements located within the conduit, each static mixer element comprising one or more deflection surfaces adapted to split and rotate said fluid's flow, wherein the array of static mixer elements comprises at least one first static mixer element and at least one second static mixer element alternately positioned along the length of the conduit, wherein at least one of the first and second static mixer elements substantially extends across the conduit's cross section, whereby undeviated flow of said fluid substantially parallel to the central axis is prevented, wherein each first static mixer element comprises four first deflection surfaces substantially symmetrically arranged around the central axis of the conduit, wherein each second static mixer element is positioned to split and rotate said fluid flow from an adjacent upstream first static mixer element, and wherein each second static mixer element comprises four second deflection surfaces substantially symmetrically arranged around the central axis of the conduit, each arranged to be substantially downstream of a corresponding first deflection surface of the adjacent upstream first static mixer element; and at least four elongate ultraviolet radiation sources located within the conduit and mutually spaced from each other and from the conduit's inner wall and substantially symmetrically arranged around the central axis of the conduit, the elongate ultraviolet radiation sources extending through apertures in the deflection surfaces of the static mixer elements, and the elongate ultraviolet radiation sources further being mutually spaced and arranged so that fluid may pass through a region located between each adjacent pair of the four ultraviolet radiation sources, wherein the array of static mixer elements and the elongate ultraviolet radiation sources are arranged for relative motion therebetween along longitudinal axes of the ultraviolet radiation sources, whereby the relative motion wipes surfaces of the elongate ultraviolet radiation sources.