Device for killing organisms in water with light and its use

Abstract

Device (1) for killing organisms with which water (2) is contaminated by exposing the water (2) to light (5) - a conduit (3) for conveying the water (2), - a light source (4) providing the light (5) and - a light distributor (6) which directs the light (5) through a light exit window (7) onto the water (2) in the pipe (3), - wherein the light distributor (6) is arranged within the conductor (3) such that an annular free conductor cross-section (14) remains between the outer circumferential surface (15) of the light distributor (6) and the inner circumferential surface (16) of the conductor (3), - wherein the light exit window (7) is arranged in the outer circumferential surface (15) of the light distributor (6) and is extended in a ring-shaped manner along the entire ring-shaped free conductor cross-section (14) and - wherein the light distributor (6) distributes the light (5) from the light source (4) through the light exit window (7) uniformly over the entire annular free cross-section (14) of the conductor, characterized in that the light distributor (6) widens the light (5) coming from the light source (4) with a lens optic (20) and then focuses it into an annular focal line (23) in the free cross-section (14) of the conductor, wherein the focal line (23) is at a distance from the light exit window (7) and at a distance from the inner circumferential surface (16) of the conductor (3).

Description

TECHNICAL FIELD OF THE INVENTION

[0001] The invention relates to a device for killing organisms contaminated with water by exposing the water to light. More specifically, the present invention relates to a device having the features of the preamble of independent claim 1.

[0002] The term “water” here includes all liquids that essentially consist of water, in particular water in and from open bodies of water, such as saline seawater, but also wastewater and water that has been deliberately treated with additives, such as cooling water containing antifreeze.

[0003] The organisms with which the water is contaminated may, in particular, be potential pathogens and, on the other hand, organisms that tend to multiply in the water, causing it to become cloudy, and / or grow on surfaces wetted by the water. STATE OF THE ART

[0004] WO 2016 / 107829 A1 discloses a system for preventing the growth of biofilms on water-wetted surfaces, in particular the exterior surfaces of a ship. The system involves irradiating the surfaces with light while moving relative to a light source. The light is UV-A light or UV-C light, which is provided by a laser.

[0005] Preventing the growth of biofilms of marine organisms by irradiating surfaces or the water adjacent to them with ultraviolet light in order to kill the marine organisms or prevent them from adhering to the underwater surfaces is known from US 5 322 569 A.

[0006] WO 1983 / 001400 A1 discloses a method for removing material from an outer surface of a ship, in which a laser beam is directed onto the material.

[0007] US Pat. No. 6,407,385 B1 discloses a method for removing foreign material particles from a sample surface using pulsed laser light. The surface containing the foreign particle to be removed is wetted with water. Otherwise, the path of the laser light to the sample surface is kept free of water. The wavelength of the laser light is selected so that it is absorbed by the water.

[0008] US 2020 / 0369352 A1 discloses a method for preventing the growth of fouling on surfaces and ships using UV-C light, which is supplied via a light-conducting optical medium adjacent to the respective surface.

[0009] WO 2019 / 178624 A1 discloses a device for disinfecting pipelines using electromagnetic radiation, in particular UV light. A source of the electromagnetic radiation is arranged on a spray chain, which is held at a distance from the floor and lateral wall areas by means of spacers. The wavelength range of the electromagnetic radiation is between 200 and 300 nm.

[0010] DE 10 2015 115 988 A1 discloses a device for treating liquids with at least one UV illuminating element directed at the liquid, which has a measuring device for measuring a flow rate and / or contamination of the liquid. The measuring device is coupled to a control device that controls the power of the UV illuminating element. The UV illuminating element is arranged in a hollow body through which the liquid flows, such that it is in direct contact with the liquid.

[0011] EP 2 829 519 B1 discloses a device for water disinfection and sterilization by treatment with ultraviolet radiation, which comprises at least one emitter with wavelengths in the UV-C range. The emitter is arranged in a disinfection reactor that can be submerged in a water storage tank. The disinfection reactor consists of an elongated reactor chamber open on both sides with a system inlet and a system outlet. In addition to the UV-C emitter, a pump is arranged in the reactor chamber to generate a volume flow through the reactor chamber. The housing of the disinfection reactor in the area of ​​the emitter is made of UV-C-permeable quartz glass.

[0012] From US 6 570 167 B1 a device for treating a liquid with UV light is known, in which the liquid flows through an annular space between a glass tube enclosing a UV lamp and an aluminum tube arranged coaxially thereto.

[0013] A device for disinfecting liquids is known from AT 514 097 A1. A UV-emitting diode is mounted on a carrier located in a UV-permeable cylindrical body, which is located on the axis of a pipe through which the liquid to be disinfected flows. The liquid to be disinfected is set into a rotating motion by a pinhole before irradiation. The diode emitting the UV light is operated in pulsed or timed mode. The UV light from the diode is evenly distributed via a reflecting cone in the flow space between the UV-permeable cylindrical body and the pipe running around it. OBJECT OF THE INVENTION

[0014] The invention is based on the object of demonstrating a device for killing organisms contaminated in water by exposing the water to light, which ensures that the light acts with high intensity on all the water conducted through a pipe. SOLUTION

[0015] The object of the invention is achieved by a device having the features of independent claim 1 and its use having the features of claim 15. Preferred embodiments of the device according to the invention are defined in the dependent claims. DESCRIPTION OF THE INVENTION

[0016] A device according to the invention for killing organisms contaminated in water by exposing the water to light comprises a conduit for conducting the water, a light source providing the light, and a light distributor directing the light through a light exit window onto the water in the conduit.

[0017] As already stated at the beginning, the term “water” here includes all liquids consisting essentially of water, in particular water in and from open waters, such as saline seawater, but also wastewater and water deliberately mixed with additives, such as cooling water mixed with antifreeze.

[0018] The light directed onto the water can, in principle, be any light of sufficient intensity to kill the organisms contaminated with the water. Laser light is preferred because it can not only be provided with sufficient intensity, but its monochromaticity and collimation also offer advantages when directed onto the water.

[0019] In the device according to the invention, the light distributor is arranged within the line such that an annular free line cross-section remains between the outer peripheral surface of the light distributor and the inner peripheral surface of the line. The light exit window is arranged in the outer peripheral surface of the light distributor and extends circumferentially along the entire annular free line cross-section. The light distributor distributes the light from the light source through the light exit window evenly across the entire annular free line cross-section. This implies, in particular, that light passes into the free line cross-section from each circumferential region of the light exit window, which extends along the entire annular free line cross-section.

[0020] Using a lens optic, the light distributor expands the light coming from the light source and then focuses it into an annular focal line in the free cable cross-section, whereby the focal line runs at a distance from the light exit window and at a distance from the inner circumferential surface of the cable.

[0021] The seamless distribution of light from the light source across the entire annular extent of the light exit window is achieved in the device according to the invention in particular by the light distributor fanning out the light coming from the light source toward the light exit window using a conical mirror. It is understood that the light coming from the light source strikes the conical mirror along the conical axis of the conical mirror, with the light intensity distribution being as rotationally symmetrical as possible to the conical axis. Preferably, the conical mirror fans out the light radially to the conical axis of the conical mirror. The conical mirror can have a polished mirror surface. Preferably, the conical mirror is provided with a highly reflective coating matched to the wavelength of the light in order to redirect the light toward the light exit window with as little loss as possible.For example, monochrome laser light is advantageous in this respect.

[0022] Specifically, the conical mirror of the device according to the invention can have a full angle of approximately 70° to 90° and be arranged coaxially with the light exit window within the outer peripheral surface of the light distributor. When the light coming from the light source is collimated and incident parallel to the conical axis of the conical mirror, it is deflected radially to its conical axis by a conical mirror with a full angle of 90°. The light thus spans the distance between the light exit window and the inner surface of the line via the shortest possible path.

[0023] Because the light distributor uses the lens optics to focus the light coming from the light source onto the focal line in the free cross-section of the cable. This line runs in a ring around the light distributor, preferably at equal distances from the light exit window and the inner circumferential surface of the cable. The light rays do not strike the conical mirror parallel to its conical axis. To still fan out the light radially to the conical axis with the conical mirror, a conical mirror with a full angle of less than 90° is required. The exact value of the full angle depends on the focal length of the lens optics of the light distributor.

[0024] The lens optics comprises at least one lens for shaping, in particular for expanding, collimating and / or focusing, the light coming from the light source. Expanding the light with the lens optics has the advantage of facilitating a uniform distribution of the light across the entire annular free line cross-section with the help of the conical mirror. A small offset of the conical axis of the conical mirror relative to the central axis of the incident light results in a much smaller error in the desired uniformity of the light distribution across the free line cross-section with a large cross-section of the incident light than with a small cross-section of the incident light. Focusing the light coming from the light source into the annular focal line within the free line cross-section maximizes the intensity with which the light affects the organisms in the water.Preferably, the lens optics of the light distributor has a long focal length of at least five times the maximum diameter of the expanded light from the light source, so that the light from the light source is spatially concentrated to a high intensity over the entire free line cross-section between the light exit window and the inner circumferential surface of the line.

[0025] Specifically, the outer peripheral surface of the light distributor and the inner peripheral surface of the line in the device according to the invention can be arranged in the shape of a cylindrical shell section and coaxially to each other. This creates ideal conditions for a uniform distribution of the light from the light source across the entire annular, free line cross-section.

[0026] The line of the device according to the invention can comprise a T-piece, with the light distributor mounted on a flange that closes the opening at one end of the T-piece's cross pipe and ends freely in the cross pipe. The water then flows between the other two openings of the T-piece through a 90° bend.

[0027] The light source of the device according to the invention can be arranged outside the line. The light source can be coupled to the light distributor via a light guide or directly. In the latter case, the light source can be mounted on the same flange as the light distributor. Arranging the light source inside the line, so that it is cooled by the water, is also possible. In any case, the light source preferably comprises a laser.

[0028] The outer peripheral surface of the light distributor, including the light exit window, can be formed with a transparent tube. In particular, the transparent tube is a glass tube, preferably a quartz glass tube, which allows the light from the light source to pass through as unhindered as possible.

[0029] In the device according to the invention, the light source typically provides light with a wavelength of visible light or the adjacent UV range. Light with a wavelength between 300 nm and 700 nm is preferred, and even more preferably between 400 nm and 550 nm. In this wavelength range of blue light, the absorption of light by pure water is only slight. The light can therefore spread through the water until it reaches organisms to be killed. In other words, light in the preferred wavelength range is selectively absorbed by the organisms to be killed and is therefore particularly efficient in killing the organisms. The blue light is preferably provided in a narrow wavelength band by a laser of the light source.

[0030] In particular, the light source of the device according to the invention provides the light with such a light output and the light distributor of the device according to the invention distributes the light from the light source over the annular free line cross-section in such a way that in all areas of the annular free line cross-section a surface power density or intensity of the light transverse to its propagation direction of at least 1 W / mm 2 is achieved. This ensures that every portion of the water flowing through the annular free cross-section is exposed to light with at least this intensity. Preferably, the achieved surface power density, i.e., the intensity with which every portion of the water flowing through the annular free cross-section is exposed to light, is at least 2 W / mm 2or even more. The surface power density, or intensity, of the light is increased by focusing or spatially concentrating the light from the light source within the free flow cross-section. With high light intensity, damage to organisms is much more likely than with the same light power distributed over a larger area perpendicular to its direction of propagation.

[0031] At the same time, the specific light output of the light per 1 mm of circumferential length of the inner circumferential surface of the line opposite the light exit window can be at least 10 W, preferably at least 20 W. This means that the light is provided with such a light output and distributed over the annular free line cross-section that at least 5 W, preferably at least 10 W, of light output per 1 mm of circumferential length reaches the entire inner circumferential surface of the line opposite the light exit window. This ensures that every portion of the water flowing through the free line cross-section is exposed to a minimum light dose, which depends on the flow velocity at which the water flows through the free line cross-section, but can easily be adjusted so that it is sufficient to cause significant damage to the organisms contained therein.

[0032] In the device according to the invention, it is advantageous if the inner circumferential surface of the conduit opposite the light exit window is mirrored. It is particularly advantageous if the light incident through the light exit window onto the inner circumferential surface of the conduit is reflected back in the opposite direction by the mirrored inner circumferential surface, thus increasing the intensity of the light acting on the water flowing through the free flow cross-section. This is achieved by the light radially impinging on the inner circumferential surface in the shape of a cylindrical jacket section, or by the inner circumferential surface being shaped like a concave mirror, which focuses the incident light back onto its annular focal line.

[0033] Specifically, the distance between the light exit window and the opposite surface of the cable can be between 20 mm and 150 mm. Typically, this distance is between 50 mm and 100 mm for the device according to the invention.

[0034] If the water is not pumped through the annular free pipe cross-section of the device according to the invention by another external pump, the device according to the invention can have its own pump which pumps the water through the annular free pipe cross-section.

[0035] In a further development of the device according to the invention, a turbidity sensor is arranged in front of the light exit window in the flow direction of the annular free line cross-section and / or a fluorescence sensor is arranged behind the light exit window, and a controller of the device activates the light source depending on the signals from the turbidity sensor and / or the fluorescence sensor. The turbidity of the water detected by the turbidity sensor influences the range of the light in the water. Thus, with greater turbidity, a greater light output must be provided so that each portion of the water flowing through the annular free line cross-section is exposed to the light with a certain minimum intensity or minimum dose. To ensure a certain minimum dose, the flow rate of the water can also be reduced.The fluorescence sensor can be designed to detect autofluorescence of living organisms. The fluorescent light sensor, located downstream of the light exit window, can thus be used to check whether the organisms in the water have actually been killed by the light or at least damaged to such an extent that they will die. Additional sensors can be used to measure other parameters such as the water flow rate through the free pipe cross-section, the water temperature, the water salinity, and the water pressure, which can influence the required light output of the light source to eliminate a registered contamination of the water with organisms by exposure to the light.

[0036] The line of the device according to the invention can be connected to a ballast water tank, in particular on board a ship, to a cooling water system, for example an open cooling water system on board a ship, but also to a closed cooling water system, to a drinking water tank or to a waste water tank in order to at least prevent the proliferation and / or growth of organisms in the respective tank or system or to completely disinfect the water in the respective tank so that it is suitable, for example, for the irrigation of plants used for food or even as drinking water.

[0037] Advantageous further developments of the invention emerge from the patent claims, the description and the drawings.

[0038] The number of features mentioned in the patent claims and the description is to be understood as meaning that exactly this number or a greater number than the stated number is present, without the need for the explicit use of the adverb "at least." Thus, for example, if reference is made to a sensor, this is to be understood as meaning that exactly one sensor, two sensors, or more sensors can be present. The features mentioned in the patent claims may be supplemented by further features or may be the only features present in the subject matter of the respective patent claim.

[0039] The reference signs contained in the patent claims do not represent a limitation of the scope of the subject-matter protected by the patent claims. They serve solely to make the patent claims easier to understand. BRIEF DESCRIPTION OF THE CHARACTERS

[0040] In the following, the invention is further explained and described with reference to preferred embodiments shown in the figures. Fig. 1 shows a device according to the invention in longitudinal section and Fig. Figure 2 shows a schematic light absorption spectrum of water. FIGURE DESCRIPTION

[0041] The Fig. The device 1 shown in Figure 1 is used to kill organisms with which a body of water 2 is contaminated. The device 1 has a line 3 that conducts the water 2. A light source 4 of the device 1 provides light 5, with which the device 1 acts on the water 2 in order to kill the organisms in the water 2. The light 5 is directed by a light distributor 6 through an exit window 7 onto the water 2 in the line 3. Specifically, the light distributor 6 is cylindrical in shape with a rounded tip 8, which is directed opposite to a flow direction 9 of the water 2 through the line 3, indicated by arrows. The cylindrical light distributor 6 projects coaxially into a cross pipe 10 of a T-piece 11 of the line 3. The cross pipe 10 has pipe flanges 12 at both ends.An opening at one of the two ends of the cross pipe 10 is closed by a flange 13 attached to the pipe flange 12 there, on which the light distributor 6 is mounted and from which the light distributor 6 projects into the cross pipe 10, where it ends freely with its rounded tip 8. The water 2 flowing into the cross pipe 10 passes past the light distributor 6 through an annular free line cross-section 14, which is delimited inwards by the cylindrical outer peripheral surface 15 of the light distributor 6, in which the light exit window 7 is arranged, and outwards by the inner peripheral surface 16 of the line 3, which is also shaped like a cylindrical section. The water 2 is then diverted by a baffle 17 into a connecting pipe 18 of the T-piece 11 with a further pipe flange 19 at the third opening of the T-piece 11.

[0042] According to Fig. 1, the light 5 from the light source 4 is fed to the light distributor 6 via a light guide 21. The light source 4 can couple the light 5, which it usually generates with a laser, for example a diode laser, but can also couple it directly and thus without loss into the light distributor 6 and for this purpose can also be mounted on the flange 13. The light distributor 6 distributes the light 5 from the light source 4 through the light exit window 7 evenly over the entire annular free line cross-section 14. For this purpose, the light distributor 6 has a Fig. 1, which expands the light 5 and focuses it via a conical mirror 22 into a focal line 23 running annularly around the light exit window 7. The conical mirror 22 is arranged with its conical axis 24 coaxial with the outer peripheral surface 7, and the light 5 coming from the light source 4 falls onto the conical mirror 22 with an intensity distribution that is rotationally symmetrical to the conical axis 24. The conical mirror 22 fans out the light 5 radially to its conical axis 24 so that it spans the entire annular free line cross-section 14. The inner surface 16 is preferably mirrored in the area opposite the light exit window 7 in order to reflect the light 5 incident here radially back to the conical axis 24.Upstream of the light exit window 7 is a turbidity sensor 25, which is designed with an LED 27 in a transmission configuration opposite a detector 26 and emits light 28 toward the detector 26. The turbidity sensor 25 detects the turbidity of the water 2 as a result of sediments and organisms contained therein. Downstream of the light exit window 7 is a fluorescence sensor 29 in a transmission configuration with an LED 31 opposite a detector 30, which emits monochromatic, for example, blue, light 32. The light 32 stimulates living organisms to fluoresce. The detector 30 registers the intensity of fluorescent light from such living organisms at wavelengths other than that of the light 32. The fluorescence sensor 29 thus detects the residual contamination of the water 2 with still living organisms. In other words, the killing of organisms in water 2 is checked by the absence of fluorescence.A controller 33 controls or regulates a light output of the light 5 emitted by the light source 4 depending on the signals of the turbidity sensor 25 and the fluorescence sensor 29. The controller 33 can take into account the signals of further sensors 34.

[0043] The line 3 of the device 1 can be connected, for example, to a ballast water tank on board a ship, a cooling water system on board a ship, a drinking water tank, or a wastewater tank. The water 2 can be circulated through the device 1 with the aid of a pump (not shown here) or can be exposed to the light 5 only as it flows into or out of the respective tank.

[0044] The light 5 from the light source 4 is preferably blue laser radiation with a wavelength between 400 and 550 nm. As shown in Fig.As the schematic light absorption spectrum of water shown in Figure 2 shows, the absorption coefficient of water is particularly low in this wavelength range. This means that pure water 2 allows light 5 of this wavelength to pass through it essentially unhindered. Thus, the light 5 reaches all areas of the free flow cross-section 14 with high intensity. However, organisms in the water 2 struck by the light 5 absorb the light 5 and are thereby killed. LIST OF REFERENCE SYMBOLS 1 device 2 water 3 Line 4 Light source 5 light 6 light distributors 7 light exit windows 8 rounded tip 9 Direction of water flow 10 Cross tube 11 T-piece 12 Pipe flange 13 Flange 14 annular free cable cross-section 15 Outer peripheral surface 16 inner peripheral surface 17 Baffle 18 pipe section 19 Pipe flange 20 lens optics 21 light guides 22 conical mirrors 23 focal line 24 Cone axis 25 Turbidity sensor 26 Detector 27 LED 28 light 29 Fluorescence sensor 30 detector 31 LED 32 light 33 Control 34 Sensor

Claims

[1] Device (1) for killing organisms with which a water (2) is contaminated by exposing the water (2) to light (5) with - a pipe (3) for conducting the water (2), - a light source (4) providing the light (5) and - a light distributor (6) which directs the light (5) through a light exit window (7) onto the water (2) in the pipe (3), - wherein the light distributor (6) is arranged within the line (3) in such a way that an annular free line cross-section (14) remains between the outer peripheral surface (15) of the light distributor (6) and the inner peripheral surface (16) of the line (3), - wherein the light exit window (7) is arranged in the outer circumferential surface (15) of the light distributor (6) and is extended in a ring-shaped manner in the circumferential direction along the entire annular free line cross-section (14) and - wherein the light distributor (6) distributes the light (5) from the light source (4) through the light exit window (7) evenly over the entire annular free line cross-section (14), characterized by that the light distributor (6) expands the light (5) coming from the light source (4) with a lens optic (20) and then focuses it into an annular focal line (23) in the free line cross-section (14), wherein the focal line (23) runs at a distance from the light exit window (7) and at a distance from the inner circumferential surface (16) of the line (3). [2] Device (1) according to claim 1, characterized by that the light distributor (6) fans out the light (5) coming from the light source (4) with a conical mirror (22), preferably radially to the conical axis (24) of the conical mirror (22), towards the light exit window (7). [3] Device (1) according to claim 2, characterized bythat the conical mirror (22) has a full angle of 60° to 90° and is arranged coaxially to the light exit window (7) within the outer peripheral surface (15) of the light distributor (6). [4] Device (1) according to one of the preceding claims, characterized by that the focal line (23) runs at equal distances from the light exit window (7) and from the inner circumferential surface (16) of the line (3). [5] Device (1) according to one of the preceding claims, characterized by that the outer peripheral surface (15) of the light distributor (6) and the inner peripheral surface (16) of the line (3) are arranged in the shape of a cylinder jacket section and coaxially to one another. [6] Device (1) according to one of the preceding claims, characterized by that the line (3) has a T-piece (11), wherein the light distributor (6) is mounted on a flange (13) which closes an opening at one end of the cross tube (10) of the T-piece (11) and ends freely in the cross tube (10). [7] Device (1) according to one of the preceding claims, characterized by that the light source (4) comprises a laser and is preferably arranged outside the line (3). [8] Device (1) according to one of the preceding claims, characterized by that the outer peripheral surface (15) of the light distributor (6) including the light exit window (7) is formed from a transparent glass tube, preferably a quartz glass tube. [9] Device (1) according to one of the preceding claims, characterized by that the light source (4) provides the light (5) with a wavelength between 300 nm and 700 nm, preferably between 400 nm and 550 nm. [10] Device (1) according to one of the preceding claims, characterized by that the light source (4) provides the light (5) with such a light output and the light distributor (6) distributes the light (5) in such a way, - that in all areas of the annular free line cross-section (14) a surface power density of the light (5) transverse to its propagation direction of at least 1 W / mm 2 , preferably at least 2 W / mm 2 , is achieved and / or - that the specific light output of the light (5) is at least 10 W, preferably at least 20 W, per 1 mm of circumferential length of the inner circumferential surface (16) of the line (3) opposite the light exit window (7). [11] Device (1) according to one of the preceding claims, characterized by that the inner peripheral surface (16) of the line (3) opposite the light exit window (7) is mirrored. [12] Device (1) according to one of the preceding claims, characterized by that the distance between the light exit window (7) and the opposite inner circumferential surface (16) of the line (3) is between 20 mm and 150 mm, preferably between 50 mm and 100 mm. [13] Device (1) according to one of the preceding claims, characterized by that a pump of the device (1) pumps the water (2) through the annular free pipe cross-section (14). [14] Device (1) according to one of the preceding claims, characterized by that in the flow direction of the annular free line cross-section (14) a turbidity sensor (25) is arranged in front of the light exit window (7) and a fluorescence sensor (29) is arranged behind the light exit window (7) and that a controller (33) of the device (1) controls the light source (4) depending on signals from the turbidity sensor (25) and the fluorescence sensor (29). [15] Use of a device (1) according to one of the preceding claims for killing organisms with which a water (2) is contaminated, wherein the line (3) is connected to - a ballast water tank, in particular on board a ship, - a cooling water system, in particular on board a ship, - a drinking water tank or - is connected to a waste water tank.

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