UV reactor comprising a mixing device

Abstract

The invention relates to a UV reactor (10) for irradiating a medium (104), comprising an assembly (105) of LEDs (102, 103) which are designed to irradiate the medium (104), and a mixing device (108) for mixing electromagnetic radiation (15) which has been emitted by each of the LEDs (102). The UV reactor (10) also comprises a detection device (110) which is designed to detect a failure of at least one defective LED (103), and a control device (112) for controlling the LEDs (102), which is designed to increase a control power of the LEDs (102) if the failure of at least one defective LED (103) has been detected.

Description

[0001] UV REACTOR WITH MIXING DEVICE

[0002] DESCRIPTION

[0003] UV reactors for irradiating media, such as water or air, typically feature LEDs (light-emitting diodes) capable of generating electromagnetic radiation in the UV range, particularly in the UV-C range. Generally, concepts are sought that can ensure reliable irradiation of the medium, even if individual LEDs fail.

[0004] The present invention is based on the object of providing an improved UV reactor.

[0005] According to embodiments, the problem is solved by the subject matter of the independent patent claims. Further developments are defined in the dependent patent claims.

[0006] According to embodiments, a UV reactor for irradiating a medium comprises an array of LEDs configured to irradiate the medium, and a mixing device for mixing electromagnetic radiation emitted by each of the LEDs. The UV reactor further comprises a detection device configured to detect a failure of at least one defective LED, and a control device for controlling the LEDs, which is configured to increase a control power of the LEDs when the failure of at least one defective LED has been detected.

[0007] According to embodiments, the light mixing device can comprise a mixing chamber. Furthermore, the light mixing device can comprise a reflector element for deflecting electromagnetic radiation toward the medium. According to embodiments, the detection device is arranged between the array of LEDs and the mixing device.

[0008] For example, the detection device may comprise a beam splitter and a detector, and the beam splitter is configured to feed a portion of the emitted electromagnetic radiation to the detector.

[0009] According to embodiments, the detector can be designed as a planar detector, and the control device is configured to selectively control LEDs of the array of LEDs.

[0010] According to further embodiments, the detector has a plurality of detector elements, and the detection device is arranged to direct electromagnetic radiation emitted by the individual LEDs to an associated detector element.

[0011] For example, the detection device may comprise a detector that is more than 95% transparent to electromagnetic radiation emitted by the LEDs.

[0012] According to embodiments, the detector comprises a solar cell.

[0013] According to embodiments, the detection device comprises a converter element and a detector, wherein the converter element is configured to convert electromagnetic radiation emitted by the LEDs into visible light and the detector is configured to detect visible light.

[0014] For example, the detection device comprises a reduced reactor chamber filled with a converter material, an optical element for supplying electromagnetic radiation to the reduced reactor chamber and a detector.

[0015] According to embodiments, the detection device can be configured to determine a position of the at least one defective LED.

[0016] According to further embodiments, the detection device can be configured to determine a number of defective LEDs.

[0017] For example, the control device can be configured to increase the control power of LEDs arranged adjacent to the defective LED.

[0018] According to further embodiments, the control device can be configured to increase the control power of LEDs arranged adjacent to the defective LED more than the control power of the remaining LEDs.

[0019] According to embodiments, the control device may be configured to supply a continuous signal to the LEDs, wherein the continuous output signal is increased when the failure of an LED has been detected.

[0020] According to further embodiments, the control device can be configured to supply a pulse-width modulated signal to the LEDs, wherein the pulse width of the signal is increased when the failure of an LED has been detected.

[0021] The accompanying drawings are intended to provide an understanding of embodiments of the invention. The drawings illustrate embodiments and, together with the description, serve to explain the same. Further embodiments and many of the intended advantages will be apparent from the following detailed description. The elements and structures shown in the drawings are not necessarily to scale. Like reference numerals refer to like or corresponding elements and structures.

[0022] Fig. 1A shows a schematic cross-sectional view of a UV reactor transverse to the flow direction of a medium to be irradiated according to embodiments.

[0023] Fig. 1B shows a schematic cross-sectional view along a flow direction of a medium to be irradiated according to embodiments.

[0024] Fig. 2 shows a cross-sectional view of a UV reactor according to further embodiments.

[0025] Fig. 3A shows a schematic view of a UV reactor according to further embodiments.

[0026] Fig. 3B shows an example of an arrangement of LEDs.

[0027] Fig. 3C illustrates examples of detector signals for different modulation methods.

[0028] Fig. 4A shows a schematic cross-sectional view of a UV reactor with a transparent detector according to further embodiments.

[0029] Fig. 4B shows a plan view of elements of a transparent detector. Fig. 4C shows a plan view of elements of a transparent detector according to further embodiments.

[0030] Fig. 5 shows a schematic cross-sectional view of a UV reactor according to further embodiments.

[0031] Fig. 6A shows a schematic cross-sectional view of a UV reactor with a converter element according to embodiments.

[0032] Fig. 6B shows an example of a converter element.

[0033] Fig. 7A shows an example of a signal that can be generated by the control device.

[0034] Fig. 7B shows another example of a signal that can be generated by the control device.

[0035] In the following detailed description, reference is made to the accompanying drawings, which form a part of the disclosure, and in which specific embodiments are shown for purposes of illustration. In this context, directional terminology such as "top", "bottom", "front", "back", "over", "on", "in front of", "behind", "fore", "rear", 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 is for the purpose of explanation only and is in no way limiting.

[0036] The description of the embodiments is not limiting, as other embodiments exist and structural or logical changes may be made without departing from the scope defined by the claims. In particular, elements of embodiments described below may be combined with elements of other described embodiments, unless the context indicates otherwise.

[0037] The term "vertical," as used in this description, is intended to describe an orientation that is substantially perpendicular to the first surface of a substrate or semiconductor body. The vertical direction may, for example, correspond to a growth direction during layer growth.

[0038] The terms "lateral" and "horizontal," as used in this description, are intended to describe an orientation or alignment that is substantially parallel to a first surface of a substrate or semiconductor body. This may, for example, be the surface of a wafer or a chip (die).

[0039] The horizontal direction can, for example, lie in a plane perpendicular to a growth direction during the growth of layers.

[0040] Fig. 1A shows a cross-sectional view of an example of a UV reactor 10 for irradiating a medium 104. The cross-sectional view is taken, for example, in a direction perpendicular to a flow direction of the medium 104 to be irradiated. The medium 104 to be irradiated can be, for example, water or air. According to embodiments, the medium 104 to be irradiated can also be any other material, for example a material to be oxidized or a material to be subjected to a surface treatment, for example a material to be hardened. In general, the medium 104 to be irradiated can be solid, liquid, or gaseous. The term "flow direction" indicates a relative movement between the UV reactor 10 and the medium 104 to be irradiated. It is self-evident that the medium 104 to be irradiated can also be stationary, while the UV reactor 10 moves in the opposite direction to the flow direction 106.

[0041] For example, the UV reactor 10 has a reactor chamber 100 through which the medium 104 to be cleaned flows. A part of the reactor outer wall 101 can, for example, be designed as an optical window 107, which is transparent to electromagnetic radiation emitted by the individual LEDs 102. The UV reactor further has an arrangement 105 of LEDs 102, 103. The LEDs 102, 103 are configured to irradiate the medium 104. The LEDs 102, 103 can, in particular, be implemented as LEDs that are configured to emit electromagnetic radiation in the UV range, for example in the UV-C range.

[0042] The UV reactor further comprises a mixing device 108 which is configured to mix electromagnetic radiation which has been emitted by the LEDs 102. Furthermore, the UV reactor 10 comprises a detection device 110 which is configured to detect a failure of at least one LED 103. In addition, the UV reactor 10 comprises a control device 112 for controlling the LEDs 102, 103. The control device 112 is configured to increase a control power of the LEDs if the failure of at least one LED 103 has been detected. For example, the control device 112 can be configured to increase the control power of the LEDs depending on a number of defective LEDs 103.

[0043] In this way, LED failure can be compensated for in a simple and reliable manner. In particular, the occurrence of "leakage paths," i.e., areas that are insufficiently illuminated due to an LED failure, can be avoided.

[0044] The functionality of the control device for increasing the drive power of the LEDs 102 will be explained in more detail with reference to Figs. 7A, 7B. Overall, the term "increased drive power" refers to a signal strength observed over a certain period of time, for example, a temporally increased operating current.

[0045] The detection device 110 can, for example, be arranged between the array 105 of LEDs and the mixing device 108. According to further embodiments, the detection device 110 can be arranged on a side of the reactor chamber 100 and the medium 104 to be irradiated that is spaced apart from the array of LEDs 105.

[0046] For example, the mixing device 108 can be designed as a mixing chamber 109 or comprise one. For example, the emitted electromagnetic radiation 15 can radiate through the mixing chamber 109. The interior of the mixing chamber 109 can be coated, for example, with a highly reflective material, for example PTFE (polytetrafluoroethylene, Teflon). For example, PTFE can cause diffuse reflection. According to further embodiments, the mixing chamber 109 can also comprise a quartz glass rod. According to embodiments, an inner side of the mixing chamber 109 facing the arrangement 105 can be coated with a specularly reflective material, for example an Al coating, in order to avoid back reflections into the individual LEDs 102, 103.

[0047] The mixing device 108 is arranged between the LEDs 102, 103 and the medium 104. The mixing device 108 is configured to mix electromagnetic radiation 15 emitted by each of the LEDs 102, so that in the region of the reactor chamber 100, electromagnetic radiation 15 from two adjacent LEDs 102 is superimposed on one another.

[0048] According to further examples, the mixing device 108 can be designed such that electromagnetic radiation from three LEDs 102 is superimposed on one another. For example, these three LEDs 102 can be arranged next to one another along one direction. For example, the superimposition of the electromagnetic radiation of the LEDs can occur in the entire volume through which the medium 104 flows. For example, the superimposition can also occur in at least 90% of the volume through which the medium 104 flows. As shown in Fig. 1A, the mixing device 108 can be configured to widen the emission cones or emission cones 124 of the individual LEDs 102 so that the emission cones 124 of the next-but-one LEDs 102 touch or intersect.For example, the emission cones 124 of the next but one LEDs 102 can intersect or touch in at least 90% of the volume through which the medium 104 flows or even in the entire volume through which the medium 104 flows.

[0049] Fig. 1B shows a schematic cross-sectional view of the UV reactor 10 along a flow direction 106 of the medium 104 to be cleaned. As shown in Fig. 1B, several arrays 105 of LEDs can be arranged along the flow direction 106, for example on opposite sides or other positions of the reactor chamber 100. The array of LEDs can each be arranged in a direction perpendicular to the flow direction 106. For example, a

[0050] The circumference of the reactor chamber 100, as shown in Fig. 1A, can be quadrangular. According to further embodiments, a cross-section of the reactor chamber 100 can also be cylindrical or correspond to a different shape. As shown in Figs. 1A and 1B, the arrangement 105 of LEDs can each be arranged on an outer side of the reactor chamber 100. According to further embodiments, however, other arrangement possibilities are also conceivable. For example, the arrangement 15 of LEDs can also be provided in the interior of the reactor chamber 100. According to embodiments, the UV reactor 10 can also be designed without a reactor chamber. This can be the case, for example, if the medium 104 to be irradiated is solid and stationary and the UV reactor 10 moves relative to the medium 104 to be irradiated.

[0051] Fig. 2 shows a schematic cross-sectional view of a UV reactor according to further embodiments. The UV reactor 10 contains similar elements as described with reference to Figs. 1A and 1B. Deviating from embodiments shown in Figs. 1A, 1B, here the mixing device 108 comprises a mixing chamber 109 and a reflector element 111. As shown in Fig. 2, electromagnetic radiation 15 emitted by the individual LEDs 102 is first mixed in the mixing chamber 109 and then reflected by the reflector element 111 towards the UV reactor 10. The reflector element 111 can, for example, comprise a prism, for example a quartz prism, or can be implemented as a transparent element with a reflective coating, for example a PTFE coating. In the case of Fig .In the embodiment of the mixing device 108 shown in Figure 2, it is possible for the arrangement 105 of LEDs 102, 103 to be arranged laterally next to the reactor chamber 100. For example, the arrangement 105 of LEDs 102, 103 can be arranged such that it does not overlap with the reactor chamber 100 in the vertical and horizontal directions. Figure 3A shows a schematic view of components of a UV reactor 10 according to further embodiments. For example, here the UV reactor comprises a beam splitter 115, through which a portion of the emitted electromagnetic radiation 15 can be directed to a detector 116. A large portion of the emitted radiation 15 is directed in the direction of the reactor chamber 100. In this way, it is possible to use a large portion of the emitted electromagnetic radiation 15 to irradiate the medium 104.At the same time, it is possible to use a portion of the emitted electromagnetic radiation 15 to determine whether one or more of the LEDs are failing. For example, a first optical element 113 can be arranged between the beam splitter 115 and the detector 116. For example, the first optical element 113 can suitably direct the electromagnetic radiation 15 onto the detector 116.

[0052] According to embodiments, the detector 116 can be designed as a planar detector. According to further embodiments, it is also possible for the detector 116 to be an arrangement of individual detector elements 1162, 1162, ... 116 n by which individual signals can be individually detected. For example, if the detector 116 comprises a plurality of individual detector elements 116i, 1162, ... 116 n, it is possible, if necessary using the first optical element 113, which can be configured to direct the emitted electromagnetic radiation to a detector element assigned to each of the LEDs, to directly determine whether at least one of the LEDs fails, how many LEDs 103 are defective and to determine a position of the defective LEDs 103.

[0053] If the detector 116 is designed as a planar detector, the individual LEDs of the array 105 can be controlled individually, for example using suitable modulation methods. By evaluating the received signal of the detector 116, it can then be determined whether and which of the individual LEDs 103 are failing. Using a modulation method, for example, the detection accuracy can be increased. Furthermore, it can be determined how many LEDs 103 are defective and at which positions they are present. This is explained in more detail with reference to Fig. 3C.

[0054] The second optical element 114 may, for example, be a mixing chamber 109, a suitable lens or another suitable element for superimposing the beams 15.

[0055] In the arrangement shown in Fig. 3A, the array 105 of LEDs can also be arranged outside the reactor chamber 100. Here, too, it is possible that the array 105 does not overlap the reactor chamber 100 either vertically or horizontally.

[0056] According to all embodiments, for example, if it can be determined by evaluating the received signal of detector 116 which of the LEDs 103 is defective, the control device can be configured to increase the control power of selected LEDs or to increase it more than the control power of other LEDs. For example, the control device can be configured to increase the control power, in particular, of LEDs 124 that are arranged adjacent to a defective LED 103.

[0057] This is explained in more detail in Fig. 3B. According to Fig. 3B, the LEDs 124 which are arranged adjacent to the defective LED 103 are driven by the control device 112 with a higher drive power than the other LEDs 102. According to embodiments, the control device 112 can drive the immediately adjacent LEDs 124 with an increased drive power. According to further embodiments, the control device can also drive the LEDs adjacent to the immediately adjacent LEDs 124 with an increased drive power. Furthermore, the drive power of the remaining LEDs 102 can also be increased compared to operation without defective LEDs. In this way, the energy efficiency of the UV reactor, in particular of the control device 112, can be increased.

[0058] The right part of Fig. 3C illustrates detector signals I as a function of time t for various modulation methods when a planar detector 116 is used. The left part of Fig. 3C shows an arrangement 105 of LEDs 102 with a defective LED 103. Under (i) a method is shown in which the control device controls all LEDs 102, 103 except one. Here, at t=ti, the detector signal I is increased, and the non-controlled LED corresponds to the defective LED 103. Accordingly, the defective LED 103 can be detected by identifying the non-controlled LED at time ti.

[0059] (ii) shows a process in which all LEDs 102, 103 are continuously controlled. At time t=ti, the intensity decreases. Since all LEDs are continuously controlled, it is not possible to determine which of the LEDs is defective.

[0060] (iii) shows a method in which the LEDs are controlled sequentially. At time t=ti, the detector signal I is reduced. Accordingly, the defective LED 103 can be identified.

[0061] As described, using a suitable modulation method, it is possible to determine which and how many of the LEDs 103 are defective. As a result, as described, for example, with reference to Fig. 3B, the driving power of the adjacent LEDs can be increased or increased more than that of the non-adjacent LEDs.

[0062] According to embodiments illustrated in Fig. 4A, the detector is embodied as a transparent detector 117. For example, the detector 117 may be more than 95% transparent to the radiation 15 emitted by the LEDs 102. The detector 117 is arranged between the array 105 of LEDs and the mixing device 108. For example, the transparent detector 117 may have the structure of one or more solar cells. For example, the solar cells may be designed such that they are transparent to UV radiation 15 emitted by the LEDs 102. According to further embodiments, they may be arranged spaced apart from one another on a transparent substrate.

[0063] As shown in Fig. 4B, for example, individual detector elements 119 can be arranged above a transparent substrate 118. For example, the individual detector elements 119 can be arranged in rows and columns. Accordingly, it is possible to precisely determine the position of defective LEDs 103. By selecting a suitable size for the individual detector elements 119, it can be achieved that a large part of the emitted electromagnetic radiation 15 is transmitted through the detector 117.

[0064] According to further embodiments, which are illustrated in Fig. 4G, the transparent detector 117 may also comprise a transparent substrate 118 with a detector surface 120 arranged thereabove. In this case, for example, the position of defective LEDs 103 may be detected by sequentially controlling the individual LEDs, similar to that described with reference to Figs. 3A and 3C.

[0065] According to further embodiments, an arrangement with a reduced reactor chamber 121 can also be arranged between the arrangement 105 of LEDs and the reactor chamber 100. As shown in Fig. 5, for example, a first optical element 113, for example one or more lenses for collimating incident electromagnetic radiation 15, can be arranged between the arrangement 105 of LEDs and the reduced reactor chamber 121. Furthermore, a detector 116 can be arranged adjacent to the reduced reactor chamber 121. Furthermore, a second optical element 114, for example for expanding the rays transmitted through the reactor chamber 121, can be provided. In this way, a mixing of the emitted light rays 15 also takes place. For example, a liquid with a converter material can be arranged in the reduced reactor chamber 121.By irradiation with electromagnetic radiation in the UV range, the converter material can be excited, resulting in an optical signal. This can be detected by the detector 116. The detector 116 can, for example, be configured to detect UV radiation. According to further embodiments, the detector 116 can also be configured to detect visible light. By monitoring the intensity of the detected signal, it can be determined whether or not defective LEDs 103 are present. By using a modulation method in which individual LEDs are controlled, the detection accuracy can be increased and it can be determined which LED 103 is defective.

[0066] Fig. 6A shows a schematic cross-sectional view of a UV reactor 10 according to further embodiments. Unlike in embodiments shown, for example, in Fig. 4A, here a converter element 122 is arranged between the array 105 of LEDs and the mixing device 108. For example, the converter element 122 can be coated with a suitable phosphor. In this way, a luminous pattern is generated in the converter element 122, which can be recorded, for example, by the detector 116. As a result, the presence of defective LEDs 103 can be detected. For example, the detector 116 can be arranged directly in front of the array 105 of LEDs or behind the array of LEDs 105 with respect to an arrangement direction of the array of LEDs 105 and the reactor chamber 100. Since the converter element

[0067] 122 is configured to convert the emitted electromagnetic radiation into visible light, a detector 116 that detects visible light can be used. This is significantly more cost-effective than a detector that detects UV radiation. According to embodiments, the phosphor can be evenly distributed on the converter element 122.

[0068] According to further embodiments, which are shown in Fig. 6B, it is also possible that individual phosphorus areas

[0069] 123 are arranged on the converter element 122.

[0070] Figures 7A and 7B show examples of signals used by the driver 112 to drive the array 105 of LEDs. As shown in Figure 7A, the driver 112 may be configured to provide a continuous signal to the array 105 of LEDs. If the failure of an LED has been detected, the continuous output signal is increased. This is illustrated in Figure 7A by the dashed line.

[0071] According to embodiments illustrated in Fig. 7B, the control device may also be capable of supplying pulse-width-modulated signals to the LEDs. In this case, the pulse width of the signals may be increased if the failure of an LED 103 has been detected. This is illustrated in Fig. 7B by the dashed line.

[0072] As described, according to embodiments, LED failure can be compensated for in a simple and reliable manner. In particular, the occurrence of "leakage paths," i.e., areas that are insufficiently irradiated due to an LED failure, can be avoided. As a result, maintenance of the UV reactor is simplified, since failed LEDs cannot be replaced immediately.

[0073] The UV reactor 10 described here can be used, for example, for cleaning, for example, disinfecting water. According to embodiments, the UV reactor 10 can also be used for other treatment systems, for example, an oxidation reactor, for disinfecting surfaces, or for surface treatment such as curing processes in the printing industry.

[0074] Although specific embodiments have been illustrated and described herein, those skilled in the art will recognize that the specific embodiments shown and described may be replaced by a variety of alternative and / or equivalent designs without departing from the scope of the invention. This 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. LIST OF REFERENCE SIGNS

[0075] 10 UV reactor

[0076] 15 electromagnetic radiation

[0077] 100 reactor chamber

[0078] 101 Reactor outer wall

[0079] 102 functional LEDs

[0080] 103 defective LEDs

[0081] 104 Medium

[0082] 105 Arrangement of LEDs

[0083] 106 Flow direction

[0084] 107 optical window

[0085] 108 Mixing device

[0086] 109 Mixing chamber

[0087] 110 Detection device

[0088] 111 Reflector element

[0089] 112 Control device

[0090] 113 first optical element

[0091] 114 second optical element

[0092] 115 beam splitters

[0093] 116 Detector

[0094] H öx ^.-ll ön detector element

[0095] 117 transparent detector

[0096] 118 transparent substrate

[0097] 119 Detector element

[0098] 120 detector pool

[0099] 121 reduced reactor chamber

[0100] 122 Converter element

[0101] 123 Phosphorus area

[0102] 124 emission cones

Claims

CLAIMS 1. UV reactor (10) for irradiating a medium (104), comprising: a reactor chamber (100) through which the medium (104) can flow; an arrangement (105) of LEDs (102, 103) which are designed to irradiate the medium (104); a mixing device (108) which is arranged between the LEDs (102, 103) and the medium (104) and which is designed to mix electromagnetic radiation (15) which has been emitted by each of the LEDs (102) so that, in the region of the reactor chamber (100), electromagnetic radiation from two adjacent LEDs (102) is superimposed on one another; a detection device (110) which is designed to detect a failure of at least one defective LED (103); and a control device (112) for controlling the LEDs (102), which is configured to increase a control power of the LEDs (102) when the failure of at least one defective LED (103) has been detected.

2. UV reactor (10) according to claim 1, wherein the light mixing device (108) comprises a mixing chamber (109).

3. UV reactor (10) according to claim 2, wherein the light mixing device (108) comprises a reflector element (111) for deflecting electromagnetic radiation (15) in the direction of the medium (104).

4. UV reactor (10) according to one of the preceding claims, wherein the detection device (110) is arranged between the Arrangement (105) of LEDs and the mixing device (108) is arranged.

5. UV reactor (10) according to claim 4, wherein the detection device (110) comprises a beam splitter (115) and a detector (116), and the beam splitter (115) is configured to supply a portion of the emitted electromagnetic radiation (15) to the detector (116).

6. UV reactor (10) according to claim 5, wherein the detector (116) is designed as a planar detector and the control device (112) is configured to selectively control LEDs (102, 103) of the array (105) of LEDs.

7. UV reactor (10) according to claim 5, wherein the detector (116) comprises a plurality of detector elements (116i, 1162,... 116 n ), and the detection device (110) is arranged to direct electromagnetic radiation emitted by the individual LEDs (102) to an associated detector element (116i).

8. UV reactor (10) according to claim 4, wherein the detection device (110) comprises a detector (117) which is more than 95% transparent to electromagnetic radiation (15) emitted by the LEDs (102).

9. UV reactor (10) according to claim 8, wherein the detector (117) has a solar cell.

10. UV reactor (10) according to claim 4, wherein the detection device (110) comprises a converter element (122) and a detector (116), wherein the converter element (122) is arranged to detect electromagnetic radiation emitted by the LEDs (102). radiation (15) into visible light and the detector (116) is arranged to detect visible light.

11. UV reactor (10) according to claim 4, wherein the detection device (110) comprises a reduced reactor chamber (121) filled with a converter material, as well as an optical element (113) for supplying electromagnetic radiation to the reduced reactor chamber (121) and a detector (116).

12. UV reactor (10) according to one of the preceding claims, wherein the detection device (110) is arranged to detect a position of the at least one defective LED (103).

13. UV reactor (10) according to one of the preceding claims, wherein the detection device (110) is arranged to determine a number of defective LEDs (103).

14. UV reactor (10) according to claim 12 or 13, wherein the control device (112) is configured to increase the control power of LEDs (124) arranged adjacent to the defective LED (103).

15. UV reactor (10) according to claim 12 or 13, wherein the control device (112) is configured to increase the control power of LEDs (124) arranged adjacent to the defective LED (103) more than the control power of the remaining LEDs (102).

16. UV reactor (10) according to one of the preceding claims, wherein the control device (112) is arranged to supply a continuous signal to the LEDs (102, 103) for controlling, wherein the continuous output signal is increased if the failure of at least one LED (103) has been detected.

17. UV reactor (10) according to one of claims 1 to 15, wherein the control device (112) is arranged to supply a pulse-width modulated signal to the LEDs (102, 103) for control, wherein the pulse width of the signal is increased if the failure of at least one LED (103) has been detected.

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