Method and device for biofouling prevention on vessels by means of UV radiation and surface modification

Abstract

The invention provides an object (10), that during use is at least partly submerged in water, wherein the object (100) is selected from the group consisting of a vessel (1) and an infrastructural object (15), the object (10) further comprising an anti-biofouling system (200) comprising an UV emitting element (210), wherein the UV emitting element (210) is configured to irradiate with UV radiation (221) during an irradiation stage one or more of (i) a first part (111) of an external surface (11) of said object (10) and (ii) water adjacent to said first part (111) of said external surface (11) of said object (10), wherein the object (10) further comprises protruding elements (100) with the UV emitting element (210) configured between the protruding elements (100) and configured depressed relative to the protruding elements (100).

Claims

1. A method of protecting an object against biofouling, the method comprising: providing an anti-biofouling system, the anti-biofouling system comprising an UV emitting element; providing protruding elements to the object, wherein the UV emitting element is configured between the protruding elements, wherein the UV emitting element is configured depressed relative to the protruding elements; irradiating with the UV emitting element one or more of a portion of an external surface of the object and water adjacent to the portion of the external surface of the object.

2. The method according to claim 1, wherein the external surface comprises the protruding elements.

3. An anti-biofouling system comprising an UV emitting unit comprising a surface profile, wherein the surface profile comprises at least one protruding element; and an optical medium, wherein the optical medium is configured to provide UV radiation from a light source to a radiation escape surface of the optical medium, wherein the optical medium is configured depressed relative to the at least one protruding element.

4. An anti-biofouling system according to claim 3, wherein the optical medium is configured between the at least one protruding element, wherein the optical medium comprises one or more of the light sources, wherein the one or more light sources comprise solid state light sources, wherein the optical medium comprises silicone as waveguide material, wherein the surface profile and protruding elements comprise steel.

5. A method for providing an anti-biofouling system in the form of UV emitting unit to an object comprising: attaching anti-biofouling system to the external surface of the object, wherein the anti-biofouling system comprises: a surface profile comprising protruding elements; and an optical medium, wherein the optical medium is configured between the protruding elements, wherein the optical medium is configured depressed relative to the protruding elements.

6. The method according to claim 1, wherein the UV emitting element comprises an optical medium, wherein the optical medium is configured to provide the UV radiation of a light source to the one or more of the portion of the external surface of the object and water adjacent to the portion of the external surface of the object, wherein the optical medium is configured between the protruding elements, wherein the optical medium is configured depressed relative to the protruding elements.

7. The method according to claim 6, wherein the optical medium comprises one or more of the light sources, wherein the one or more light sources comprise solid state light sources, wherein the optical medium comprises silicone.

8. The method according to claim 1, wherein the external surface comprises the protruding elements.

9. The method according to claim 1, wherein the object comprises a surface profile, wherein the surface profile comprises the protruding elements, wherein the surface profile is attached to the external surface, wherein the anti-biofouling system comprises the protruding elements.

10. The method according to claim 9, wherein the object comprises a UV emitting unit, wherein the UV emitting unit comprises the surface profile and an optical medium, wherein the surface profile is attached to the external surface.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings in which corresponding reference symbols indicate corresponding parts, and in which:

(2) FIGS. 1a-1b schematically depict some embodiments and variants; and

(3) FIGS. 2a-2j schematically depict some embodiments and variants.

(4) The drawings are not necessarily on scale.

DETAILED DESCRIPTION OF THE EMBODIMENTS

(5) FIG. 1a schematically depicts an object 10 that during use is at least partly submerged in water 2. The object 100 is selected from the group consisting of a vessel 1 and an infrastructural object 15 (see also FIG. 1b). The object 10 further comprises an anti-biofouling system 200 comprising an UV emitting element 210, wherein the UV emitting element 210 is configured to irradiate with UV radiation 221 during an irradiation stage one or more of (i) a first part 111 of an external surface 11 of said object 10 and (ii) water 2 adjacent to said first part 111 of said external surface 11 of said object 10. Reference 13 indicates the water line; reference LL indicates a load line (of a vessel 1). The protruding elements may especially only be arranged e.g. within a range of e.g. 1 meter above and 1 meter below the load line LL (see also below).

(6) As indicated above, the term “vessel”, indicated with reference 1, may e.g. refer to e.g. a boat or a ship (ref 10a in FIG. 1b), etc., such as a sail boat, a tanker, a cruise ship, a yacht, a ferry, a submarine (ref 10d in FIG. 1b), etc. etc., like schematically indicated in FIGS. 1b. The term “infrastructural object”, indicated with reference 15, may especially refer to aquatic applications that are in general arranged substantially stationary, such as a dam/sluice (references 10e/10f in FIG. 1b), a pontoon (ref 10c in FIG. 1b), an oilrig (ref 10b in FIG. 1b), etc. etc.

(7) In a specific embodiment, the object 10 further comprises a control system 300 (see e.g. FIG. 2g) configured to control said UV radiation 221 as function of input information comprising information of one or more of (i) a location of the object 10, (ii) movement of the object 10, (iii) a distance of the object 10 to a second object 20, and (iv) a position of the part 111 of the external surface 11 relative to the water. Hence, especially the anti-biofouling system is configured to control said UV radiation as function of input information comprising information of a human UV radiation exposure risk. In an embodiment, the anti-biofouling system 200 may include an integrated control system 300 and an integrated sensor 310. Hence, the control system 300 may be configured to control an intensity of the anti-fouling light as function of one or more of (i) a feedback signal related to a biofouling risk and (ii) a timer for time-based varying the intensity of the anti-fouling light. Such feedback signal may be provided by the sensor.

(8) The object 10 may further comprises protruding elements 100 with the UV emitting element 210 configured between the protruding elements 100 and configured depressed relative to the protruding elements 100. FIGS. 2a-2c schematically depict how the anti-biofouling system 200 or the UV emitting element 210 may be configured between protruding elements. Here, by way of example the anti-biofouling system 200 essentially consists of the UV emitting element 210, which essentially consists of an optical medium 270 (waveguide) for guiding UV radiation to the radiation escape surface, indicated with reference 230, of the optical medium 270. However, the anti-biofouling system 200 may also comprise a plurality of UV emitting elements 210, and also other elements, such as a control unit, etc. (see also e.g. above). In FIG. 2a schematically three variants of the configuration of the anti-biofouling system 200/UV emitting elements 210/optical media 270 are shown.

(9) In the variant I, the radiation escape window is 230 is substantially flat and the protruding elements 100 are especially rims (see also below), defining a substantially rectangular cavity 121 wherein the biofouling system 200/UV emitting elements 210/optical media 270 is configured, depressed relative to the protruding elements 100. Reference d3 indicates the height difference between protruding element 100 and the UV emitting element; 210; reference d4 indicates the height difference between protruding element 100 and the optical medium 270. By way of example, a light source 220, such as a solid state light source, is embedded in the optical medium.

(10) In variant II, substantially the same cavity 121 is provided between the protruding elements 100, but the radiation escape surface 230 is concave. Here, by way of example two light sources 220 are embedded in the optical medium 270. Note that the distances (of each respective light source) to the protruding elements 100 differ. Hence, the light source 220 has two or more nearest neighboring protruding elements 100, wherein a first shortest distance d1 between a first nearest neighboring protruding element 100 and the light source 220 is equal to or less than 50% of a second shortest distance d2 between a second nearest neighboring protruding element 100 and said light source 220.

(11) In variant III, the cavity 121 provided between the protruding elements 100 has a concave bottom or cavity back side 122. Here, the radiation escape surface 230 is chosen to be flat. Further, by way of example an optical fiber or fiber 225 is comprised by the optical medium 270. A light source 220 (not depicted) may couple UV radiation 221 into the fiber, which on its turn couples light into the optical medium. Methods to couple UV radiation into a fiber and/or into an optical medium are known in the art. FIG. 2a may also depict embodiments of UV emitting units 1210 comprising a surface profile 110 comprising protruding elements 100, and an optical medium 270 configured to provide UV radiation 221 of a light source 220 to a radiation escape surface 230 of optical medium 270, wherein the optical medium 270 is configured between the protruding elements 100 and configured depressed relative to the protruding elements 100. Such unit 1210 may be configured to an existing external surface of an object (see also FIG. 2c).

(12) FIG. 2b schematically depicts three variants of configurations of the UV emitting elements and the protruding elements 100, here configured as rims 102, in a top view. Variant I of FIG. 2b may e.g. correspond to variant I of FIG. 2a. Note the row of light sources 220. Variant II in FIG. 2b may correspond to variant II of FIG. 2a, though here two fibers 225 have been chosen (instead of light sources 220). Note that at an edge the light source 220 is configured to couple UV radiation 221 into the fiber 225. Variant III of FIG. 2b may e.g. correspond to variant III of FIG. 2a, with a fiber 225 between the two rims 102.

(13) FIG. 2c schematically depicts a configuration of a plurality of UV emitting elements 210 to an external surface 11 of an object 10, such as a vessel 1. The UV emitting elements 210 may e.g. be comprised by a single anti-biofouling system 200. Due to the protruding elements 100, a collision with e.g. a quay 16 is not necessarily detrimental to the in general more sensible optical elements, such as a light source or a UV emitting element 210. Reference 13 indicates the water line (also indicated with LL).

(14) Instead of rims, also pin shaped or otherwise shaped protruding elements 100 may be applied. FIGS. 2d-2e schematically depict some embodiment, with FIG. 2d, variant I showing the UV emitting elements being configured between the protruding elements 100, and with variant II showing a top view wherein the protruding elements 100 protrude through openings 107 in the UV emitting element 210, such as an opening in the optical medium 270. FIG. 2e schematically depicts a similar variant as variant II of FIG. 2d, but now in side view or cross-sectional view (perpendicular cross-section).

(15) FIG. 2f shows a chicken-wire embodiment where light sources 210, such as UV LEDs, are arranged in a grid and connected in a series of parallel connections. The LEDs can be mounted at the nodes either through soldering, gluing or any other known electrical connection technique for connecting the LEDs to the chicken wires. One or more LEDs can be placed at each node. DC or AC driving can be implemented. If AC is used, then a couple of LEDs in anti parallel configuration may be used. The person skilled in the art knows that at each node more than one couple of LEDs in anti parallel configuration can be used. The actual size of the chicken-wire grid and the distance between UV LEDs in the grid can be adjusted by stretching the harmonica structure. The chicken-wire grid may be embed in an optical medium.

(16) FIG. 2g schematically depicts an embodiment wherein a vessel 1, as embodiment of the object 10, comprises a plurality of anti-biofouling systems 200 and/or a one or more of such anti-biofouling systems 200 comprising a plurality of UV emitting elements 210. For instance, dependent upon the height of the specific such anti-biofouling system 200 and/or the height of the UV emitting elements 210, such as relative to a water (line), the respective UV emitting elements 210 may be switched on. FIG. 2g also indicates the load line LL. About 0.5-2 m above, indicated with h2, and about 0.5-2 m below the load line LL, indicated with h1, the protruding elements 100 may be applied.

(17) FIG. 2h schematically depicts in more detail a variant of e.g. the UV emitting unit 1210 with a curved cavity backside 122. Such curvature may be used to provide a good distribution of the UV radiation 221 over the UV radiation escape surface. Optionally, the cavity back side 122 may also include an UV reflective coating 123.

(18) FIG. 2i schematically depicts a kind of negative of FIG. 2d. Here, a unit is provided which can be used as a protruding element, with a recession 1107 for hosting the light source, or especially the UV emitting element 210, or the optical medium 270, or the entire anti-biofouling system 200. Here, by way of example the recession or indentation 1107 is round. However, also other shapes, including square or rectangular may be used. Further, the configuration may be differently “packed” like a hexagonal configuration, etc. Such unit may be as a whole be attached to an external surface of an object. Note that thereby the surface of the unit may become (at least part of the) external surface of the object.

(19) In an embodiment, at least part of the anti-biofouling system, such as UV emitting element, could be arranged underneath a protruding element. That is, the protruding element might e.g. be a hollow steel strip, with UV emitting element inside/embedded. For instance, the protruding element anti-biofouling system or UV emitting element, could be made in a factory, and installed as an add-on strip, directly on the original external surface of the object, such as a steel hull, see e.g. FIG. 2j

(20) As indicated above, ships hulls are often damaged due to mechanical impact of fenders or the harbor quay, objects floating in the water, tugs, petrol supply ships etc. (see illustration in FIG. 2c). The mechanical damage is concentrated along the load line (see FIG. 2c/2g, ref. LL): ca 2 meter above till 2 meter below. Herein, this area will be indicated with “boot top”. It is also an area exposed to both seawater and sunshine, making the environment harsh.

(21) The waterline can vary of course depending on the load of the ship but is normally close to the load line indicated on the ship. Herein, a UV based antifouling construction to keep the hull of ships clean is suggested. Amongst others, this idea describes a solution to protect this construction against mechanical stress. It may only need to be applied at the boot top.

(22) For new build ships the steel hull plate could be rolled in the curve shape. In case of existing ships, with the solution as defined herein, added afterwards, a steel profile can be attached to the ship. The curved surface can be coated with a highly UV reflective material, such as paint containing BaO.sub.2 or other reflective ingredients. The vertical curve should be optimized to generate sufficient spread of the UV light. This could be a parabolic form with the light source in de focus point. The light source can e.g. be a quartz fiber with light originating from a UV laser and/or a string of UV LED's. The sizes of the profile and distance between the LED's will depend on the power emitted per cm.sup.2. To be effective as antifouling the optical power leaving the radiation escape surface should especially be above 1 mW/dm.sup.2

(23) The UV light source may be embedded in a UV transparent material, such as silicone. The steel profile stands out more than the transparent material, thus giving mechanical protection, but limited to a few millimeters to ensure the UV light keeps the steel rim clean as well. The material and the light source, including wiring can be attached to the profile before the solution is added to the ship, being manufactured under factory conditions. Instead of a curved surface other shapes are possible, e.g. in FIGS. 2a (II) and 2b (II) the same idea is drawn with a T shaped profile. This has the advantage the light source can be protected even further by placing it in the corner. Other embodiments may be based on the addition of bumpers made of steel, tough silicon or glass may also be possible (see FIGS. 2d-2e).

(24) The term “substantially” herein, such as in “substantially all light” or in “substantially consists”, will be understood by the person skilled in the art. The term “substantially” may also include embodiments with “entirely”, “completely”, “all”, etc. Hence, in embodiments the adjective substantially may also be removed. Where applicable, the term “substantially” may also relate to 90% or higher, such as 95% or higher, especially 99% or higher, even more especially 99.5% or higher, including 100%. The term “comprise” includes also embodiments wherein the term “comprises” means “consists of”. The term “and/or” especially relates to one or more of the items mentioned before and after “and/or”. For instance, a phrase “item 1 and/or item 2” and similar phrases may relate to one or more of item 1 and item 2. The term “comprising” may in an embodiment refer to “consisting of” but may in another embodiment also refer to “containing at least the defined species and optionally one or more other species”.

(25) Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein.

(26) The devices herein are amongst others described during operation. As will be clear to the person skilled in the art, the invention is not limited to methods of operation or devices in operation.

(27) It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. Use of the verb “to comprise” and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. The article “a” or “an” preceding an element does not exclude the presence of a plurality of such elements. The invention may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In the device claim enumerating several means, several of these means may be embodied by one and the same item of hardware. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

(28) The invention further applies to a device comprising one or more of the characterizing features described in the description and/or shown in the attached drawings. The invention further pertains to a method or process comprising one or more of the characterizing features described in the description and/or shown in the attached drawings.

(29) The various aspects discussed in this patent can be combined in order to provide additional advantages. Furthermore, some of the features can form the basis for one or more divisional applications.