UV irradiation unit, UV reactor, and method for operating a UV irradiation unit

Abstract

The invention relates to a UV irradiation unit (15, 16) for irradiating a medium (105), the UV irradiation unit comprising a housing body (107), which adjoins a treatment volume (100) through which the medium (105) can flow, and a plurality of light sources (102), which are designed to irradiate the treatment volume (100) with UV radiation, wherein the housing body (107) is largely transparent to the UV radiation (17) emitted by the light sources (102). The UV irradiation unit (15, 16) also comprises a coupling-in structure (112), which is designed to couple some of the UV radiation (17) emitted by at least one of the light sources (102) into the housing body (107) such that the UV radiation (17) or a converted radiation (18) resulting from the UV radiation is conducted through the housing body (107) via the optical waveguide effect.

Description

[0001] UV RADIATION UNIT, UV REACTOR AND METHOD FOR OPERATION

[0002] ONE UV RADIATION UNIT

[0003] DESCRIPTION

[0004] UV reactors used to irradiate media, such as water or air, for example for disinfection, have light sources capable of generating electromagnetic radiation in the UV range, particularly in the UV-C range. For example, mercury vapor lamps or UV-C LEDs (light-emitting diodes) are used as light sources. Generally, concepts are being sought to monitor the light sources during operation in order to detect a failure or impaired performance of the light sources.

[0005] The present invention is based on the objective of providing an improved UV irradiation unit, an improved UV reactor and an improved method for operating a UV irradiation unit.

[0006] According to the implementation forms, the problem is solved by the subject matter of the independent patent claims. Further developments are defined in the dependent patent claims.

[0007] According to the embodiments, a UV irradiation unit for irradiating a medium comprises a housing body adjacent to a treatment volume through which the medium can flow, and a plurality of light sources configured to irradiate the treatment volume with UV radiation, the housing body being largely transparent to the UV radiation emitted by the light sources. The UV irradiation unit further comprises an induction structure configured to couple a portion of the UV radiation emitted by at least one of the light sources into the housing body, so that the UV radiation, or a converted radiation resulting from the UV radiation, is guided through the housing body via the optical waveguide effect.

[0008] For example, the coupling structure can include a notch in the housing body on one side facing the light source.

[0009] According to the design specifications, a boundary surface of the indentation may contain a mirrored finish.

[0010] The UV irradiation unit can, according to its design, also have a converter material on a surface of the indentation facing the light source.

[0011] According to further embodiments, the coupling structure can include a notch in the housing body on a side facing away from the light source, as well as a mirrored surface on a surface of the notch facing the light source.

[0012] According to further embodiments, the coupling structure can include a notch in the housing body on a side facing away from the light source, as well as a converter material on a surface of the notch facing the light source.

[0013] According to further embodiments, the coupling structure can include a protruding area of ​​the housing body on a side facing away from the light source, as well as a mirrored surface on a surface of the protruding area facing the light source.

[0014] According to further embodiments, the coupling structure can comprise a protruding area of ​​the housing body on one side facing the light source. According to further embodiments, the light sources can be arranged inside the volume enclosed by the housing body.

[0015] According to other versions, the light sources can be arranged outside the outer surface of the housing body.

[0016] For example, the UV irradiation unit may also include a detector for detecting the radiation passed through the housing body.

[0017] According to further embodiments, a UV irradiation unit for irradiating a medium comprises a housing body adjacent to a treatment volume through which the medium can flow, and a plurality of light sources configured to irradiate the treatment volume with UV radiation, the housing body being largely transparent to the UV radiation emitted by the light sources. The UV irradiation unit may further include an optical fiber configured to guide the UV radiation emitted by at least one of the light sources along a longitudinal direction of the housing body.

[0018] For example, the light sources can be arranged inside the volume enclosed by the housing body.

[0019] According to other versions, the light sources can be arranged outside the outer surface of the housing body.

[0020] According to various embodiments, the UV irradiation unit can further include a detector for detecting the radiation transmitted through the optical fiber. Other embodiments relate to a UV reactor with the UV irradiation unit as described above.

[0021] A method for operating a UV irradiation unit as described above includes serially switching on a single light source, detecting the radiation passed through the housing body by the detector, and serially switching off the light source.

[0022] The accompanying drawings serve to illustrate exemplary embodiments of the invention. The drawings depict these embodiments and, together with the description, serve to explain them. Further exemplary embodiments and many of the intended advantages will become apparent from the detailed description below. The elements and structures shown in the drawings are not necessarily drawn to scale. Identical reference symbols refer to identical or corresponding elements and structures.

[0023] Figures 1A and 1B show schematic cross-sectional views through UV irradiation units according to various designs.

[0024] Figures 2A to 2C show different configurations of coupling structures.

[0025] Figures 3A and 3B show schematic cross-sectional views of UV irradiation units according to various designs.

[0026] Figures 4A and 4B show cross-sectional views to illustrate further coupling structures.

[0027] Figures 5A to 5D show schematic cross-sectional views of UV irradiation units according to various embodiments. Figures 6A and 6B show schematic cross-sectional views of UV irradiation units according to further embodiments.

[0028] Figures 7A and 7B show cross-sectional views to illustrate UV reactors according to various designs.

[0029] Fig. 8 summarizes a method according to implementation forms.

[0030] The following detailed description refers to the accompanying drawings, which form part of the disclosure and show specific embodiments for illustrative purposes. In this context, directional terminology such as "top," "bottom," "front," "back," "over," "on," "in front," "behind," "front," "back," etc., refers to the orientation of the figures just described. Since the components of the embodiments can be positioned in different orientations, the directional terminology serves only for explanation and is in no way restrictive.

[0031] The description of the exemplary embodiments is not limiting, as other exemplary embodiments exist and structural or logical modifications can be made without deviating from the scope defined by the patent claims. In particular, elements of the exemplary embodiments described below can be combined with elements of other described exemplary embodiments, unless otherwise indicated by the context.

[0032] Fig. 1A shows a schematic cross-sectional view of a UV irradiation unit 15, 16 according to embodiments. The UV irradiation unit 15, 16 has a housing body 107 which adjoins a treatment volume 100 through which a medium 105 to be irradiated can flow, i.e., through which a medium to be irradiated can flow. For example, the medium 105 to be treated can be air or water.

[0033] The UV irradiation unit 15, 16 has a plurality of light sources 102 configured to irradiate the treatment volume 100 with UV radiation 17. The housing body 107 is largely transparent to the UV radiation emitted by the light sources 102. For example, the light sources can be configured to emit a wavelength smaller than 390 nm. The light sources are thus configured to emit electromagnetic radiation in the UV range, in particular in the UV-C range.

[0034] The light sources 102 can, for example, include LEDs which, for instance, have nitride-containing semiconductor materials. According to further embodiments, the light sources 102 can also be implemented in any other way, for example as mercury vapor lamps.

[0035] The inset at the bottom right of Fig. 1A shows a cross-sectional view perpendicular to a direction of extension of the housing body 107, for example, parallel to the y-z plane. As shown in the inset, one or more supports 110, on each of which several light sources 102 can be arranged, can each be arranged outside a volume enclosed by the housing body 107. In this case, the treatment volume 100 is enclosed by the housing body 107.

[0036] The housing body 107 is largely transparent to the UV radiation emitted by the light sources 102. This means that the transparency of the housing body 107 is greater than 95%, for example greater than 98% or greater than 99%, relative to the emitted radiant power. The housing body 107 can, for example, be cylindrical. According to other embodiments, the housing body can also have any other cross-sectional shape in a direction perpendicular to a direction of extension of the housing body 107.

[0037] For example, the housing body 107 can be made of quartz glass. According to one embodiment, the supports 110 with the light sources 102 are arranged outside the outer wall of the housing body 107, and the medium 105 to be cleaned flows through the treatment volume 100, which is enclosed by the housing body 107.

[0038] According to further embodiments, which are shown with reference to Fig. 1B and are also consistent with the cross-sectional view shown in Fig. 1A, the plurality of light sources can also be arranged within the volume enclosed by the housing body 107, and the treatment volume is arranged outside the housing body 107.

[0039] The UV irradiation unit 15, 16 further comprises a coupling structure 112, 113, which is configured to couple a portion of the UV radiation 17 emitted by at least one of the light sources 102 into the housing body 107. As a result, the UV radiation 17 or a converted radiation 18 resulting from the UV radiation 17 is guided through the housing body 107 via the optical waveguide effect. As shown in Fig. 1A, for example, a side 125 of the housing body 107 facing the light source 102 can be provided with structures that enable the emitted radiation 17 to be coupled into the housing body 107. As shown in Fig. 1A, the coupling structures 112 can be implemented as indentations 113 or as concave areas. As shown in Figure 1A, a refraction of the emitted UV radiation 17 takes place at the transition from air to the housing body 107.As a result, a portion of the UV radiation 17 strikes the side 126 of the housing body facing away from the light source at a below-critical angle within the housing body 107. This can lead to total internal reflection and thus a light guide effect.

[0040] The portion of the incoming radiation 17 is thus guided via total internal reflection partially to the end of the housing body along the x-direction. There, this radiation can be coupled out again and detected.

[0041] In this way it is possible to monitor the function and impairment of the performance of the light sources 102.

[0042] Fig. 1B shows a cross-sectional view of the UV irradiation unit according to further embodiments. The inset at the top right of Fig. 1B shows a cross-sectional view of the UV irradiation unit 15 along a direction perpendicular to a direction of extension of the housing body 107, i.e., for example, parallel to the y-z plane. As can be seen in the inset, the light sources 102 are arranged within a volume enclosed by the housing body 107. The treatment volume 100 is arranged outside the housing body 107. As will be shown with reference to Fig. 7A, a UV reactor 10 is also arranged such that it encloses the housing body 107.

[0043] The individual elements of the UV irradiation unit 15, shown in Fig. 1B, are each similar to or identical to those shown in Fig. 1A. The individual light sources 102 can be arranged on a suitable support 110. For example, electrical lines for controlling the individual light sources 102 can be provided within the support 110. Cooling lines can also be arranged within the support 110. The individual light sources 102 can be arranged at any radial position around the support 110. As shown in the installation in Fig. 1B, several light sources 102 can be arranged along the circumference of the support 110.

[0044] Fig. 2A shows a cross-sectional view of the irradiation unit 15, 16 according to further embodiments. As shown, the indentations 113 can have any shape, for example, those that have no symmetry with respect to an axis running parallel to the z-direction. Boundary surfaces of the indentation 113 can be planar or approximately planar surfaces.

[0045] According to embodiments shown in Fig. 2B, the coupling structure can also be designed as a protruding area 115. For example, the protruding area 115 can be symmetrical with respect to an axis parallel to the z-direction. The protruding area 115 can have straight or curved surfaces.

[0046] According to embodiments shown in Fig. 2C, a mirror coating 114 can be provided within the indentation 113. According to all embodiments described here, the mirror coating 114 can, for example, comprise a metallic layer with high reflectivity. According to further embodiments, the mirror coating 114 can also be implemented by dielectric layers, which, for example, realize a Bragg reflector. Furthermore, the indentation 113 has flat surfaces. For example, in an embodiment where the indentation 113 has flat surfaces with a mirror coating 114, particularly shallow angles of incidence into the housing body 107 can be achieved. In this way, total internal reflection of the coupled radiation is ensured.

[0047] The configurations of the coupling structure 113, which are shown in Figures 2A to 2C, are applicable to the UV treatment unit shown in Figures 1A and 1B.

[0048] According to embodiments shown in Fig. 3A, the coupling structure 112 can also be realized by indentations 113 arranged on a side 126 of the housing body 107 facing away from the light source 102. In this case, a mirrored surface 114 can again be arranged on the surface of the indentation 113, so that a deflection of the incident radiation is achieved independently of the angle of incidence. The position and design of the indentation 113 can, for example, be such that only electromagnetic radiation 17 emitted by a specific light source 102 is reflected by an associated indentation 113. In this way, it can be clearly demonstrated from which light source 102 the UV radiation 17 was emitted, which is subsequently detected by a detector 121. The UV irradiation unit 16, which is shown in Fig.3A is shown, corresponds in its geometry to the irradiation unit shown in Fig. 1A, in which the light sources are arranged on an outer wall of the housing body 107.

[0049] Fig. 3B shows a similar arrangement to that in Fig. 3A. In this case, the UV irradiation unit 15 is designed such that the light sources 102 are enclosed by the housing body 107, similar to that shown in Fig. 1B. The embodiments of Figs. 4A and 4B are each applicable to the irradiation units 15 and 16 shown in Figs. 1A and 1B.

[0050] Fig. 4A shows a cross-sectional view of a UV irradiation unit 15, 16, in which a notch 113 with a mirrored surface 114 is arranged on a side 126 of the housing body 107 facing away from the light source 102. The notch can, for example, have flat or largely flat surfaces. The mirrored surface 114 is arranged on a flat surface facing an associated light source 102. In this way, a particularly shallow angle of the UV radiation 17, 18 guided through the housing body 107 can also be achieved.

[0051] Fig. 4B shows an arrangement in which the coupling structure 112 is realized as a protruding area 115 or as a convex area. Additionally, part of the surface of the protruding area 115 is mirrored with a reflective coating 114. For example, a flat surface facing the light source 102 is mirrored. The protruding area 115 is arranged on a side 126 of the housing body 107 facing away from the light source 102.

[0052] As will be shown later with reference to Figures 7A and 7B, the UV reactor can further comprise a detector configured to detect the radiation 17, 18 passed through the housing body 107. The detector 121 can be a component of the UV reactor or an external component. According to further embodiments, the detector 121 can also be a component of the UV irradiation unit 15, 16. According to further embodiments, the coupling structure 112 can also comprise a converter material 116 by which the radiation passed through the housing body 107 is converted. In this way, it is possible to use a more cost-effective detector, configured, for example, to detect electromagnetic radiation with a longer wavelength than that of the emitted UV radiation. Accordingly, more cost-effective detection can be achieved in this way.In general, the wavelength of electromagnetic radiation emitted by a light source 102 can be converted using a converter material containing a phosphor or phosphor.

[0053] Examples of phosphors include metal oxides, metal halides, metal sulfides, metal nitrides, and others. These compounds may also contain additives that cause them to emit specific wavelengths. For example, the additives may include rare-earth materials. YAG:Ce is one example of a yellow phosphor. 3+ (with cerium-activated yttrium aluminum garnet (Y3A150I2)) or (Sri.7Bao.2Euo.i) SiO4 can be used. Other phosphors can be found at MSiO4:Eu 2+ , in which M can be Ca, Sr, or Ba. By selecting the cations with an appropriate concentration, a desired conversion wavelength can be chosen. Many other examples of suitable phosphors are known.

[0054] As shown in Fig. 5A, the converter material 116 can be arranged within a recess 113. The light sources 102 can be arranged outside the volume enclosed by the housing body 107, as shown in Fig. 1A.

[0055] Fig. 5B shows a cross-sectional view of the UV irradiation unit, in which the light sources are arranged inside the housing body 107. In this case, the coupling structures 112 with the converter material 116 can be realized in a similar manner to that shown in Fig. 5A.

[0056] According to the embodiments shown in Figs. 5A and 5B, the indentations 113 are arranged on the side 125 of the housing body 107 facing the light source 102.

[0057] According to the embodiments shown in Fig. 5C, the indentation 113 with the converter material 116 can also be arranged on the side 126 of the housing body 107 facing away from the light source 102.

[0058] Fig. 5D illustrates an arrangement in which the light sources 102 are arranged inside the volume enclosed by the housing body 107. The recess 113 with the converter material 116 is located on the side 126 of the housing body 107 facing away from the light source 102.

[0059] Fig. 6A shows a cross-sectional view of a UV irradiation unit 15, 16, in which optical fibers 117 are provided, through which UV radiation emitted by at least one of the light sources 102 can be guided along a longitudinal direction of the housing body 107, for example the x-direction.

[0060] Unlike the representation shown in Figures 1 to 5, the emitted UV radiation is thus guided not via the housing body 107, but via the optical fiber 117. For example, the optical fibers 117 can each be assigned to a corresponding light source 102. The optical fibers 117 can, for example, run through the support 110. For example, the UV irradiation unit 16 can be designed such that the individual light sources 102 are arranged outside an outer wall of the housing body 107. According to embodiments shown in Figure 6B, the light sources 102 can also be arranged inside the volume enclosed by the housing body 107.

[0061] Fig. 7A shows a cross-sectional view of a UV reactor 10 with a UV irradiation unit 15, as shown, for example, in the preceding figures. Here, the light sources 102 are arranged, for example, such that they are located within the volume enclosed by the housing body 107. Fig. 7A also shows a non-functional light source 109 that does not emit UV radiation. As shown in Fig. 7A, the UV irradiation unit 15 or several irradiation units 15 are arranged inside a reactor chamber 106, which may, for example, be made of stainless steel. For example, a medium 105 to be irradiated may be introduced into the interior of the reactor chamber 106 via an inlet 103 and discharged via an outlet 104. For example, the flow direction of the medium 105 to be irradiated may correspond to a longitudinal axis of the UV irradiation unit.According to further embodiments, the flow direction of the medium 105 to be irradiated can also differ from the longitudinal axis 108.

[0062] The UV reactor 10 can have a detector 121 configured to detect UV or electromagnetic radiation that has passed through the housing 107. The UV reactor 10 can further have an evaluation unit 122 suitable for further evaluating the detected signal. According to other embodiments, the UV reactor 10 can also have a control unit 123. For example, the control unit 123 can be configured to selectively control certain light sources 102 and not control other light sources 102, so that by evaluating the detection result obtained from the detector 121 and evaluated by the evaluation unit 122, it is possible to determine which of the light sources 102 are defective or have limited functionality.According to further embodiments, the detector 121, the evaluation unit 122, and the control unit 123, or individual units / devices, can also be located outside the UV reactor 10. According to yet other embodiments, these components can also be part of the UV irradiation unit 15. As shown in Fig. 7A, it is possible to mount the detector 121 on the same flange as the light sources 102. In this way, a separate flange is not required, and maintenance of the detector 121 can be carried out together with the light sources 102.

[0063] For example, the detector 121 can be a commercially available detector 121, for example a SiC-based detector, for example for detecting UV radiation. For example, one detector can be provided per UV irradiation unit. According to further embodiments, if the coupling structure 112 has a converter material, the detector 121 can be configured to detect electromagnetic radiation with a longer wavelength than UV radiation.

[0064] Fig. 7B shows a UV reactor in which the light sources 102 are arranged outside the volume enclosed by the housing body 107, i.e., outside the reactor chamber 106. Other components of the UV reactor 10 are similar to those described with reference to Fig. 7A.

[0065] Fig. 8 summarizes a method according to embodiments. A method for operating a UV irradiation unit as described above comprises the serial switching on (S 100) of a single light source, the detection (S 110) of the radiation passed through the housing body by the detector, and the serial switching off (S 120) of the light source. In this context, the terms "serial switching on" and "serial switching off" mean that only one light source of a UV irradiation unit 15, 16 is switched on at any one time. More precisely, the next light source 102 is only switched on once all other light sources 102 have been switched off. In this way, using, for example, one detector 121 per UV irradiation unit 15, 16, it is possible to determine exactly which of the light sources 102 is defective or has limited functionality.

[0066] As described, the housing body 107 is provided on either side 125 facing the light source 102 or on side 126 facing away from the light source 102 with coupling structures 112, which allow the UV-C radiation 17 to be coupled into the housing body 107. The portion of the radiation entering below the critical angle is then partially guided to the end of the housing body 107 by total internal reflection. There, this radiation can be coupled out again and detected. In this way, it is possible to monitor the function or impairment of individual light sources 102. The coupling structures 112 can, for example, be implemented by notches or cutouts 113, so that the radiation can enter the housing body 107 directly. The indentations or cutouts 113 may be partially mirrored so that the reflected radiation enters the housing body 107 at the critical angle and in the correct direction.

[0067] According to further embodiments, the coupling structures 112 can also be realized as concave inclusions, through which an optical element with a defined field of view is provided, which causes coupling into the housing body 107. According to further embodiments, the coupling structures can also include converter materials 116 for conversion to shorter wavelengths. In this way, it is possible to use a less expensive detector. According to yet other embodiments, it is possible to use an optical fiber 117. In this case, the associated bundle of optical fibers 117 can run outside the housing body. Accordingly, a modification of the housing body 107 is not necessary.

[0068] The coupling structures 112 can be provided at various points on the housing body 107. In this way, it is possible to monitor the entire length of the housing body 107 and thus all light sources 102 individually. When the individual light sources 102 are switched on sequentially, they can be monitored individually.

[0069] The described concept makes it possible to monitor the individual light sources without requiring additional components within the treatment volume 100 that could influence or impair the flow of the medium 105. Only a small fraction of the radiation couples into the housing 107. Because the described concept allows monitoring of the condition of all light sources 102, greater operational reliability and cost efficiency can be achieved. In particular, only the light sources that are actually defective or non-functional need to be replaced.

[0070] Although specific embodiments have been illustrated and described herein, those skilled in the art will recognize that the specific embodiments shown and described can be replaced by a multitude of alternative and / or equivalent embodiments without departing from the scope of protection of the invention. The application is intended to cover any adaptations or variations of the specific embodiments discussed herein. Therefore, the invention is limited only by the claims and their equivalents.

[0071] REFERENCE MARK LIST

[0072] 10 UV reactors

[0073] 15 UV irradiation units (inside the reactor)

[0074] 16 UV irradiation units (outside the outer wall)

[0075] 17 emitted radiation

[0076] 18 converted radiation

[0077] 100 treatment volumes

[0078] 102 light sources

[0079] 103 Admission

[0080] 104 Outlet

[0081] 105 medium to be irradiated

[0082] 106 Reactor chamber

[0083] 107 Housing body

[0084] 108 Longitudinal axis

[0085] 109 Non-functional light source

[0086] 110 carriers

[0087] 112 Coupling structure

[0088] 113 Notch

[0089] 114 Mirror coating

[0090] 115 protruding area

[0091] 116 Converter material

[0092] 117 Optical fiber

[0093] 121 Detector

[0094] 122 evaluation unit

[0095] 123 Control unit

[0096] 125 side facing the light source

[0097] 126 Side facing away from the light source

Claims

REQUIREMENTS 1. UV irradiation unit (15, 16) for irradiating a medium (105), comprising: a housing body (107) adjoining a treatment volume (100) through which the medium (105) can flow; a plurality of light sources (102) configured to irradiate the treatment volume (100) with UV radiation, wherein the housing body (107) is largely transparent to the UV radiation (17) emitted by the light sources (102); and a coupling structure (112) configured to couple a portion of the UV radiation (17) emitted by at least one of the light sources (102) into the housing body (107), such that the UV radiation (17) or a converted radiation (18) resulting from the UV radiation is guided through the housing body (107) via the light guide effect.

2. UV irradiation unit (15, 16) according to claim 1, wherein the coupling structure (112) comprises a notch (113) of the housing body (107) on a side facing the light source (102).

3. UV irradiation unit (15, 16) according to claim 2, wherein a boundary surface of the indentation (113) contains a mirror coating (114).

4. UV irradiation unit (15, 16) according to claim 2 or 3, further comprising a converter material (116) on a surface of the indentation (113) facing the light source (102).

5. UV irradiation unit (15, 16) according to claim 1, wherein the coupling structure (112) has a notch (113) in the housing- body (107) on a side (126) facing away from the light source (102) and a mirrored surface (114) on a surface of the indentation (113) facing the light source (102).

6. UV irradiation unit (15, 16) according to claim 1, wherein the coupling structure (112) comprises a notch (113) of the housing body (107) on a side (126) facing away from the light source (102) and a converter material (116) on a surface of the notch (113) facing the light source (102).

7. UV irradiation unit (15, 16) according to claim 1, wherein the coupling structure (112) comprises a protruding area (115) of the housing body (107) on a side (126) facing away from the light source (102) and a mirroring (114) on a surface of the protruding area (115) facing the light source (102).

8. UV irradiation unit (15, 16) according to claim 1, wherein the coupling structure (112) comprises a protruding area (115) of the housing body (107) on a side (125) facing the light source (102).

9. UV irradiation unit (15) according to one of the preceding claims, wherein the light sources (102) are arranged inside the volume enclosed by the housing body (107).

10. UV irradiation unit (16) according to any one of claims 1 to 8, wherein the light sources (102) are arranged outside an outer surface of the housing body (107).

11. UV irradiation unit (15, 16) according to one of the preceding claims, further comprising a detector (121) for subsequent- indicate the radiation (17, 18) passed through the housing body (107).

12. UV irradiation unit (15, 16) for irradiating a medium (105) comprising: a housing body (107) adjoining a treatment volume (100) through which the medium (105) can flow; a plurality of light sources (102) configured to irradiate the treatment volume (100) with UV radiation (17), wherein the housing body (107) is largely transparent to the UV radiation (17) emitted by the light sources (102); and an optical fiber (117) configured to guide the UV radiation (17) emitted by at least one of the light sources (107) along a longitudinal direction of the housing body (107).

13. UV irradiation unit (15) according to claim 12, wherein the light sources (102) are arranged inside the volume enclosed by the housing body (107).

14. UV irradiation unit (16) according to claim 12, wherein the light sources (102) are arranged outside an outer surface of the housing body (107).

15. UV irradiation unit (15, 16) according to one of claims 12 to 14, further comprising a detector (121) for detecting the radiation (17) guided through the optical fiber (117).

16. UV reactor (10) with the UV irradiation unit (15, 16) according to one of claims 1 to 15.

17. Method for operating a UV irradiation unit (15, 16) according to claim 11, comprising serially switching on (S100) a single light source (102); detecting (S110) the radiation (17, 18) passed through the housing body (107) by the detector (121); and serially switching off (S120) the light source (102).

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