FIELD OF THE INVENTION

The invention relates to a system that is designed to realize an anti-bio fouling effect on at least a grating of a grating unit for use with a marine object, the grating unit being configured for allowing fluid to pass therethrough and the grating being adapted to prevent items from passing through the grating unit along with the fluid.

Further, the invention relates to an assembly of a system as mentioned and a grating unit as mentioned, and also to an arrangement of a marine object and an assembly as mentioned.

BACKGROUND OF THE INVENTION

Various structures that are temporarily or permanently exposed to an aqueous environment are prone to biofouling. For instance, in a marine environment (including both seawater and freshwater), marine objects such as vessels, oil rigs, pipelines, support structures for sea-based wind turbines, structures for harvesting tidal/wave energy, etc. are subject to organisms growing on them, especially in areas that are temporarily or

permanently exposed to water. As a result, the drag of vessels increases, the moving of parts can be hampered, and filters can become clogged. In respect of the influence of bio fouling on the drag of vessels, it is noted that biofouling can involve an increase of up to 40% in fuel consumption. For the sake of clarity, it is noted that the word“vessel” as used in the present text is to be understood as referring to a watercraft such as a ship, a boat, a yacht or a submarine.

In general, biofouling is the accumulation of microorganisms, plants, algae, small animals and the like on surfaces. According to some estimates, over 1,800 species comprising over 4,000 organisms are responsible for biofouling. Hence, biofouling is caused by a wide variety of organisms, and involves much more than an attachment of barnacles and seaweeds to surfaces. Biofouling is divided into micro fouling that includes biofilm formation and bacterial adhesion, and macro fouling that includes the attachment of larger organisms. Due to the distinct chemistry and biology that determine what prevents them from settling, organisms are also classified as being hard or soft. Hard fouling organisms include calcareous organisms such as barnacles, encrusting bryozoans, mollusks, polychaetes and other tube worms, and zebra mussels. Soft fouling organisms include non-calcareous organisms such as seaweed, hy droids, algae and biofilm“slime”. Together, these organisms form a fouling community.

As mentioned in the foregoing, biofouling creates substantial problems.

Various methods have been developed to address these problems. For instance, robots exist that are designed to scrape biofouling from the hulls of vessels. Another method involves irradiating a surface that is subject to bio fouling with anti-bio fouling light. In this respect, it is noted that ultraviolet light, particularly ultraviolet light of type C, i.e. UV -C light, is known for being effective when it comes to anti-bio fouling so that good results may be achieved. It is an object of the invention to provide ways of effectively applying the method according to which anti-bio fouling light is applied in order to obtain a satisfactory level of anti-bio fouling results on at least a grating of a grating unit for use with a marine object. Examples of a grating unit as mentioned are a grating unit arranged at an inlet opening of a vessel’s sea chest and a grating unit arranged in a drive unit for use with a vessel, such as a stern drive. In the latter case, the grating unit may be used in an intake arrangement of water for cooling a motor and/or one or more other components of the drive unit, for example. It is desirable to perform an anti-biofouling action on at least a grating of grating unit for use with a marine object as otherwise it is a matter of time before the grating unit gets clogged once it has been put to operation in an aqueous environment.

SUMMARY OF THE INVENTION

The invention provides a system that is designed to realize an anti-biofouling effect on at least a grating of a grating unit for use with a marine object, the grating unit being configured for allowing fluid to pass therethrough and the grating being adapted to prevent items from passing through the grating unit along with the fluid, the system including at least one light source that is configured to emit anti-biofouling light, and the system being arrangeable with respect to the grating for emitting the anti-biofouling light towards, in and/or away from the grating in an activated state of the system.

The grating unit to which the invention is applicable may particularly be of the type that is intended to be positioned at an interface of an exterior and an interior of a marine object. The grating of the grating unit has a function in blocking items from flowing through an opening that is provided for allowing water to pass. Within the scope of the invention, the grating may be of any suitable design. In a general sense, the grating may comprise a number of elements and spaces between the elements. Maximum dimensions of items that are enabled to pass the grating along with water are determined by dimensions of the spaces between the elements of the grating. Items of which the dimensions are larger than those maximum dimensions are blocked from passing the grating.

According to the invention, an anti-bio fouling system is provided that includes at least one anti-bio fouling light source and that is arrangeable with respect to the grating, for emitting the anti-bio fouling light towards, in and/or away from the grating in an activated state of the system. Hence, the invention covers various options of achieving an anti- biofouling effect on a grating. The system according to the invention may be provided as one or more units that are to be arranged in, on, or at a distance from the grating, wherein it may or may not be advantageous for the design of the grating to be adapted, for example by making one or more parts of the grating transparent to the anti-bio fouling light. A practical way of arranging the system at a distance from the grating may involve arranging the system on the marine object. In general, the system may include at least one carrier that is arrangeable to extend from the marine object at an outside of the marine object, from the grating unit and/or in the grating unit. Further, the system according to the invention may be realized as an integral part of the grating unit, for example by designing the grating with one or more transparent parts in which discrete light sources such as UV-C LEDs are embedded.

It follows from the foregoing that practical ways of making the system according to the invention available involve providing the system i) as a part, probably an integral part, of the grating unit, ii) as an add-on of the grating unit and/or the marine object with which the grating unit is to be used, and iii) on a separate carrier. Emission of anti bio fouling light in a direction away from the grating may be achieved by arranging a suitable kind of light-emitting covering on the grating.

The system according to the invention may particularly be arrangeable with respect to the grating at a side of the grating that is a most downstream side when an inflow of fluid towards the marine object through the grating is assumed, at an opposite side of the grating, or at both sides of the grating. Assuming that the grating unit is intended to be positioned at an interface of an exterior and an interior of a marine object, as mentioned earlier, it may be advantageous to have the system only at the side of the grating that is defined as the most downstream side, as that implies that the system is in the interior of the marine object. Nevertheless, within the framework of the invention, it is very well possible for the system to be arrangeable with respect to the grating at the other side of the grating, or at both sides. The system according to the invention may include any type of light source. Also, the number of light sources can be chosen freely within the framework in the invention. It is possible to use a number of UV-C LEDs in the anti-bio fouling system, for example, but many alternatives are feasible, including alternatives in which both a light -generating device and some kind of light-guiding device are used. The at least one light source of the system may be designed to emit light in any suitable range of directions, such as a limited range of directions, wherein the at least one light source may even be of the type that is denoted as unidirectional in practice.

In the following, particulars of a number of practical embodiments of the system according to the invention are defined and explained, as combined with a grating unit. In this respect, it is noted that the invention further relates to an assembly of a system defined in the foregoing and a grating unit for use with a marine object, the grating unit being configured for allowing fluid to pass therethrough and comprising a grating that is adapted to prevent items from passing through the grating unit along with the fluid.

In the first place, the system may include at least one movable component that is configured to be movably arranged on the marine object, on the grating unit and/or in the grating unit. The at least one light source of the system may or may not be arranged on the at least one movable component. One possibility for the at least one movable component is to be arranged so as to cover the at least one light source of the system in one position and to allow exposure of the at least one light source of the system in another position. Another possibility for the at least one movable component is to serve as a carrier of the at least one light source of the system, so that the at least one light source can be moved to various positions by means of the movable component, wherein one of the possible positions may be a rest position.

In the second place, the system may comprise an elongated body that is configured to emit anti-biofouling light, wherein the elongated body is arranged to intersect with the grating, extending from a position at one side of the grating to another. The elongated body may be a tubular UV-C lamp, for example. It may be advantageous to have the elongated body at a central position in the grating so as to let the system be maximally effective in subjecting the grating to an anti-biofouling action. By letting the elongated body extend from the grating along a certain distance at the side of the grating where the items to be blocked from passing the grating may be present, the elongated body can have an additional function in hindering the items from reaching the grating and possibly even pushing away the items from the grating. It may be practical for the system to include just one elongated body, but embodiments of the system including more elongated bodies are also feasible.

In the third place, the grating unit may comprise a tube-like member defining a passage/channel of the grating unit, wherein the grating is located in or at an end of the tube- like member, wherein the system comprises at least one sheet that is configured to emit anti bio fouling light, and wherein the sheet is arranged to cover at least a portion of an interior surface of the tube-like member. For example, in a case in which the grating is located in the tube-like member, at a distance from the end of the tube-like member, the system may comprise two elongated sheets bent to a ring and arranged so as to cover portions of the interior surface of the tube-like member along the entire circumference of the tube-like member, at opposite sides of the grating.

In the fourth place, the grating may be generally bowl- shaped, and the system may be configured to emit anti-bio fouling light at a position of a rim of the generally bowl shaped grating. Preferably, in order to have the best possible anti-biofouling effect in that situation, the system is designed such that anti-biofouling light emitted at the rim of the generally bowl- shaped grating is directed towards the remainder of the grating.

In the fifth place, the grating may comprise at least one item blocking body arranged in an opening of the grating unit, and the system may comprise at least one unit that is arranged on the at least one item blocking body and configured to emit anti-biofouling light away from the at least one item blocking body. In such a case, the grating may be of a relatively uncomplicated, basic design. For example, the grating may include no more than a single item blocking body that is positioned in the middle of an opening, the item blocking body having dimensions with are slightly smaller than those of the opening so as to have space around the item blocking body through which fluid may pass. The item blocking body may be used as a carrier of at least one unit of the system, wherein the at least unit may serve for emitting anti-biofouling light in a direction away from the item blocking body.

As mentioned earlier, it may be advantageous if the grating unit comprises at least one transparent part that is configured to allow anti-biofouling light emitted by the system in the activated state thereof to pass through. According to another or an additional possibility, the grating may be especially designed so as to avoid as much as possible that an element of the grating to be irradiated with anti-biofouling light is in the shadow of another element. For example, in case the grating comprises a number of elongated parts or bars, the cross-section of those elongated parts may be triangular or square. Further, having at least one planar side on at least one elongated part of the grating may enhance effectiveness of an anti-bio fouling action on the basis of reflection of the anti-bio fouling light emitted by the system in the activated state thereof. In this respect, it is noted that it may be advantageous for the grating to be at least partially provided with a coating configured to promote reflection of the anti-biofouling light.

The invention does not only relate to a system designed to realize an anti- biofouling effect on at least a grating of a grating unit for use with a marine object and to an assembly of such a system and a grating unit as mentioned. The fact is that the invention further relates to an arrangement of a marine object and an assembly as mentioned, the marine object having at least one part accommodating a component of the system that is configured to emit anti-biofouling light and that is at a position with respect to the grating unit for emitting the anti-biofouling light towards at least the grating of the grating unit. The part of the marine object accommodating the component of the system may be a fixed bulged part of the marine object, or may be movable with respect to the marine object so as to be retractable/expandable with respect to the marine object. A practical example of a component of the system is a UV-C lamp.

The invention further involves a method for arranging the system with respect to at least a grating of a grating unit as mentioned, a method for arranging an assembly of the system and the grating unit with respect to at least a part of a marine object as mentioned, and also a method of controlling operation of the system, for putting the system in the activated state whenever appropriate. The latter method may at least involve determining an on/off condition of the at least one light source of the system in cases in which the at least one light source is not operated continuously. This may be done in any suitable manner, for example by following a protocol determining a repetitive sequence of a time that the at least one light source should be operated and a time that the at least one light source does not need to emit anti-biofouling light. Depending on the design of the system according to the invention, controlling operation of the system may further involve a step of moving at least one component of the system with respect to the grating in order to put the at least one component in any desired/predetermined position with respect to the grating.

In the context of the invention, the following considerations may be relevant. Taking into account the fact that anti-biofouling light may be harmful to human beings, which is known to be the case when UV-C light is used, the design of the system may be chosen such that the extent to which anti-biofouling light is emitted to the system’s environment in the activated state of the system is minimized. Still further, any possible practical way of powering the at least one light source of the system is covered by the invention, including using batteries, having means for generating electric power on the basis of one or more environmental aspects such as motion and temperature difference, providing wireless transfer of electric energy through coils, etc.

The above-described and other aspects of the invention will be apparent from and elucidated with reference to the following detailed description of a number of possible embodiments of a system that is designed to realize a light-based anti-bio fouling effect on at least a grating of a grating unit for use with a marine object.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be explained in greater detail with reference to the figures, in which equal or similar parts are indicated by the same reference signs, and in which:

Fig. 1 diagrammatically shows a sectional view of a grating unit for use with a marine object, and illustrates a first embodiment of an anti-bio fouling system according to the invention;

Fig. 2 diagrammatically shows a sectional view of a grating unit for use with a marine object, and illustrates a second embodiment of an anti-bio fouling system according to the invention;

Fig. 3 diagrammatically shows a sectional view of a grating unit for use with a marine object, and illustrates a third embodiment of an anti-bio fouling system according to the invention;

Fig. 4 diagrammatically shows a sectional view of a grating unit for use with a marine object, and illustrates a fourth embodiment of an anti-bio fouling system according to the invention;

Fig. 5 diagrammatically shows a front view of a grating unit for use with a marine object, and illustrates a fifth embodiment of an anti-bio fouling system according to the invention;

Fig. 6 diagrammatically shows a perspective view of a grating unit for use with a marine object; and

Fig. 7 diagrammatically shows a sectional view of the grating unit depicted in Fig. 6, and illustrates a sixth embodiment of an anti-biofouling system according to the invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

The invention is in the context of realizing an anti-bio fouling effect on at least a grating of a grating unit for use with a marine object by means of anti-biofouling light. Various feasible embodiments of the system are illustrated in the figures and the particulars of those embodiments and other possibilities existing within the framework of the invention are described and explained in the following.

Fig. 1 illustrates an anti-biofouling system 1 according to a first embodiment of the invention. The anti-biofouling system 1 is in an assembly 15 with a grating unit 20 and activatable to irradiate at least a grating 21 of the grating unit 20 with anti-biofouling light. The grating unit 20 is depicted as mounted in a marine object, Fig. 1 diagrammatic ally showing a portion of the marine object incorporating the grating unit 20 in hatched fashion. The grating unit 20 can be provided as an integral part of the marine object, but it is also possible that the grating unit 20 is provided as a separate part that is adapted to be insertable in the marine object, the marine object being designed with a cavity that is suitable for receiving the grating unit 20 in that case. An advantage of the latter possibility is that the manufacturing process of the marine object may be simplified and that it is much easier to replace the grating unit 20 if so desired.

Generally speaking, a grating unit 20 includes a passage 22 for fluid to flow through and the grating 21 as mentioned earlier, the grating 21 being arranged in the passage 22. A longitudinal dimension of the passage 22, i.e. a dimension of the passage 22 as seen in a flow direction, can be as small as the dimension of the grating 21 in the same direction, or can be larger. In the latter case, the passage 22 can be referred to as a channel 22, and the grating 21 can be located at any appropriate level in the channel 22. In the example shown in Fig. 1, the grating unit 20 includes a channel 22 having a relatively wide front section and a relatively narrow back section, the grating 21 being located at the front of the channel 22.

The grating unit 20 as shown is intended to be used as a fluid intake grating unit 20, i.e. to enable a fluid flow in a direction from the front to the back, wherein the fluid passes the grating 21 first as a result of which items are prevented from passing the grating 21 along with the fluid and reaching the interior of the grating unit 20. In the context of the invention, a practical example of a fluid is water. The grating units 20 shown in the other figures are also of the fluid intake type, which does not alter the fact that the invention also covers grating units 20 of the fluid outlet type and grating units 20 having a combined fluid intake/outlet functionality. The grating 21 can be of any functional design for the purpose of constituting one or more obstacles in the channel 22. In view thereof, the grating 21 is only

diagrammatically depicted in Fig. 1 as an array of triangles. The grating 21 and the channel 22 can have any appropriate peripheral shape, such as a circular or a square shape.

The anti-biofouling system 1 according to the first embodiment of the invention comprises an elongated body 11 that is arranged so as to extend inside the channel 22 and through the grating 21 in the assembly 15 of the system 1 and the grating unit 20. The elongated body 11 is adapted to emit anti-biofouling light and may include at least one suitable light source 10 such as a tubular UV-C lamp or an array of UV-C LEDs, for example. It may be so that the anti-biofouling system 1 comprises more than one elongated body 11, wherein it is preferred for the elongated bodies 11 to be more or less evenly distributed over the grating 21. As shown in Fig. 1, in case a single elongated body 11 is used, it may be advantageous if the elongated body 11 is at a central position in the grating unit 20.

The grating 21 may serve for supporting the at least one elongated body 11 of the anti-biofouling system 1 according to the invention, and it is also possible that one or more other supports 23 are applied, for example at a more downstream position. It is not necessary for the at least one elongated body 11 to extend all the way through the grating 21, although this is advantageous in case it is desired to provide anti-biofouling light to both sides of the grating 21. In any case, the design of the grating 21 may be adapted so as to optimize the extent to which all elements of the grating 21 can be reached by the anti- biofouling light.

By means of the anti-biofouling system 1 according to the invention, anti- biofouling effects can be realized on the grating 21, so that the grating 21 is prevented from getting clogged. All that is needed is that the at least one elongated body 11 is activated to emit anti-biofouling light. In the shown example, the elongated body 11 is arranged to perform an anti-biofouling action not only on the grating 21, but also on the surface 24 delimiting the channel 22, which will hereinafter be referred to as the channel surface 24.

The at least one light source 10 of the anti-biofouling system 1 can be operated in any suitable way, wherein the at least one light source 10 may be kept in an activated state continuously or only during certain time periods, and wherein the anti-biofouling light may be emitted at a certain intensity level or at varying intensity levels. The state of the at least one light source 10 may be set by means of a preprogrammed control device that may also be adapted to allow a human operator to determine settings of the anti-biofouling system 1. Fig. 2 illustrates an anti-biofouling system 2 according to a second

embodiment of the invention. The anti-biofouling system 2 is in an assembly 15 with a grating unit 20 and activatable to irradiate at least a grating 21 of the grating unit 20 with anti-biofouling light. The grating unit 20 is depicted as mounted in a marine object, Fig. 2 diagrammatically showing a portion of the marine object incorporating the grating unit 20 in hatched fashion.

The anti-biofouling system 2 according to the second embodiment of the invention comprises at least one sheet-like light emission unit 12 arranged on the channel surface 24 of the grating unit 20. The at least one sheet-like light emission unit 12 may include a slab of material that is transparent to the anti-biofouling light in which one or more light sources 10 such as UV-C LEDs are embedded, or a flat light emission fiber, for example. In the configuration shown in Fig. 2, the grating 21 is at a downstream position with respect to the front of the grating unit 20, and the anti-biofouling system 2 comprises two sheet-like light emission units 12 positioned in the direct vicinity of the grating 21, one on each side of the grating 21, wherein the light emission units 12 are in a ring-shaped configuration on the channel surface 24.

The grating 21 can be at any suitable position in the grating unit 20, the number of sheet-like light emission units 12 may be chosen freely, and the at least one area of the channel surface 24 to be covered by the light emission units 12 may be chosen freely as well, wherein it is even possible to fully cover the channel surface 24. The light emission units 12 may be arranged at only one or at both sides of the grating 21. In the shown example, in case the light emission units 12 include UV-C LEDs, it may be advantageous if those LEDs are of the side-emitting type and are oriented so as to emit the anti-biofouling light in a direction towards the grating 21.

As an alternative to using at least one sheet-like emission unit 12 covering at least one area of the channel surface 24, an embodiment of the anti-biofouling system is feasible in which the material of the grating unit 20 delimiting the channel 22, i.e. the material underlying the channel surface 24, is at least partially transparent to the anti- biofouling light, wherein light sources 10 such as UV-C LEDs may be embedded in the material, or wherein the material may function as a light guide extending from a position where light is generated during operation of the anti-biofouling system 2, for example.

Fig. 3 illustrates an anti-biofouling system 3 according to a third embodiment of the invention. The anti-biofouling system 3 is in an assembly 15 with a grating unit 20 and activatable to irradiate at least a grating 21 of the grating unit 20 with anti-biofouling light. The grating unit 20 is depicted as mounted in a marine object, Fig. 3 diagrammatic ally showing a portion of the marine object incorporating the grating unit 20 in hatched fashion.

The anti-bio fouling system 3 according to the third embodiment of the invention resembles the anti-bio fouling system 2 according to the second embodiment of the invention to some extent. A difference between the anti-biofouling systems 2, 3 is related to the position of the grating 21 in the grating unit 20. In the case of the anti-biofouling system 3 according to the third embodiment of the invention, the grating 21 is located in a front intake piece 25 of the grating unit 20. In view thereof, the anti-biofouling system 3 is designed so as to cover both the front intake piece 25 and an area of the channel 22 directly downstream of the front intake piece 25 with sheet-like light emission units 12.

Options mentioned earlier are equally applicable to the anti-biofouling system 3 according to the third embodiment of the invention. For example, good anti-biofouling results may be obtained when the sheet-like light emission unit 12 arranged in the channel 22 has side-emitting UV-C LEDs that are oriented towards the grating 21. Also, it may be beneficial for the design of the grating 21 to be chosen such that the extent to which one element of the grating 21 is in the shadow of another element of the grating 21 is minimized. A way to achieve this is to apply triangular shaped in the grating 21, as diagrammatically shown in both Figs. 1 and 3, or square (cross-sectional) shapes, for example. Another or additional way to achieve this is to apply an appropriate spatial configuration of elements of the grating 21 such as a staggered configuration or a V-shaped configuration instead of a configuration in a single linear row. Further, the grating 21 may be at least partially provided with a coating configured to promote reflection of the anti-biofouling light.

Fig. 4 illustrates an anti-biofouling system 4 according to a fourth embodiment of the invention. The anti-biofouling system 4 is in an assembly 15 with a grating unit 20 and activatable to irradiate at least a grating 21 of the grating unit 20 with anti-biofouling light, as indicated by arrows in Fig. 4. In this case, the grating 21 of the grating unit 20 is generally bowl-shaped, inwardly directed from a front level of the grating unit 20. In view thereof, it may be advantageous for the anti-biofouling system 4 to comprise a light emission unit 12 that is arranged as a ring at a top periphery of the bowl-shaped grating 21, as shown. Such a light emission unit 12 may be provided as a sheet-like light emission unit that is applied to an underlying surface area, but it is also possible for such a light emission unit 12 to comprise a transparent portion of material in which light sources 10 may be embedded and/or which may guide light coupled into the material at a position where the light is generated, in conformity with what has been suggested earlier. Fig. 5 illustrates an anti-biofouling system 5 according to a fifth embodiment of the invention. The anti-biofouling system 5 is in an assembly 15 with a grating unit 20 that is of a relatively simple design, including a grating 21 that consists of a single item blocking body. The grating unit 20 is depicted as mounted in a marine object, Fig. 5 diagrammatically showing a portion of the marine object incorporating the grating unit 20 in hatched fashion.

The grating 21 of the grating unit 20 is mounted in an inlet hole of the grating unit 20 with a narrow space being present between the grating 21 and the material defining the hole. The grating unit 20 may be of any suitable design, wherein the inlet hole may provide access to any suitable downstream structure, such as a shallow indent or an elongated channel. The anti-biofouling system 5 according to the invention may comprise a sheet-like light emission unit 12 that is arranged to cover the surface of the grating 21 at least partially, at one side or both sides of the grating 21. In this configuration, the anti-biofouling system 5 serves to achieve an anti-biofouling effect on the grating 21 by emitting anti-biofouling light away from the grating 21. In this respect, in conformity with what has been suggested earlier, another possibility involves an integration of the light emission functionality in the grating 21, which can be realized by having a grating 21 in which at least one light source 10 is embedded, the grating 21 being at least partially transparent to the anti-biofouling light that is emitted by the at least one light source 10 during operation of the anti-biofouling system 5.

Figs. 6 and 7 relate to an anti-biofouling system 6 according to a sixth embodiment of the invention. Fig. 7 shows the anti-biofouling system 7 in an assembly 15 with a grating unit 20, and further illustrates a larger context of the assembly 15 by depicting the grating unit 20 as mounted in a portion of a panel 30 of a marine object. Fig. 6 shows the grating unit 20, which is of a type that is generally known as strainer or scoop strainer, and that is generally used with marine objects that are movable through the water, such as vessels.

Details of the grating unit 20 can be derived from both Fig. 6 and Fig. 7. The grating unit 20 comprises a generally bowl-shaped part 26 that is partially closed at the top. The grating 21 is integrated in a part of the bottom of the bowl-shaped part 26, the bottom having an otherwise closed appearance. In Fig. 7, for the sake of illustration of the grating 21, the grating 21 is depicted as an interrupted structure in the bottom of the bowl- shaped part 26. The grating unit 20 further comprises a tube part 27 that extends from the bowl- shaped part 26 at a position where the bowl- shaped part 26 is at least partially closed at the top. The tube part 27 is open to the bowl- shaped part 26, so that when the grating unit 20 moves through the water with the grating 21 at a leading position, it is achieved that water enters the bowl-shaped part 26 through the grating 21 and is made to flow from the bowl-shaped part 26 to the tube part 27 and further down the tube part 27.

The anti-bio fouling system 6 is adapted to realize anti-bio fouling effects on both the exterior and the interior of the grating 21, and also on interior surface areas of the grating unit 20. To that end, the anti-bio fouling system 6 comprises at least two effective components. A first one of the effective components of the anti-biofouling system 6 is diagrammatically shown at the left side of Fig. 7, and comprises at least one light source 10 that is mounted in a holding structure 31 arranged on the marine object and that is at a position for radiating anti-biofouling light towards the exterior of the grating 21, as indicated by a first set of arrows in Fig. 7. When the marine object is moving, the holding structure 31 may have an additional function in creating an advantageous water flow profile at the grating 21. The holding structure 31 may have a fixed arrangement on the marine object or may be retractable/expendable with respect to the marine object so that it is possible to have the holding structure 31 out of the way if so desired. Another one of the effective components of the anti-biofouling system 6 is arranged in the interior of the grating unit 20 and serves for emitting anti-biofouling light away from one interior surface area of the grating unit 20 and towards another interior surface area of the grating unit 20, as indicated by a second set of arrows in Fig. 7. As explained earlier, at least one sheet-like light emission unit 12 may be used to this end, in which case the at least one sheet-like light emission unit 12 may at least be arranged so as to cover at least an area of the interior surface of the grating unit 20 and/or the grating unit 20 may comprise at least one portion that is transparent to the anti-biofouling light and that is provided with at least one light source 10 and/or that is coupled to a position where light is generated.

In respect of the above examples of the anti-biofouling system according to the invention explained with reference to the figures, it is noted that a fixed positioning of the components involved in emitting the anti-biofouling light is assumed. For the sake of completeness, it is noted that the invention also covers the possibility of having a movable arrangement of such components, wherein it may be so that the components are movable between an inactivated position and an activated position and/or between various activated positions.

It will be clear to a person skilled in the art that the scope of the invention is not limited to the examples discussed in the foregoing, but that several amendments and modifications thereof are possible without deviating from the scope of the invention as defined in the attached claims. It is intended that the invention be construed as including all such amendments and modifications insofar they come within the scope of the claims or the equivalents thereof. While the invention has been illustrated and described in detail in the figures and the description, such illustration and description are to be considered illustrative or exemplary only, and not restrictive. The invention is not limited to the disclosed embodiments. The drawings are schematic, wherein details that are not required for understanding the invention may have been omitted, and not necessarily to scale.

Variations to the disclosed embodiments can be understood and effected by a person skilled in the art in practicing the claimed invention, from a study of the figures, the description and the attached claims. In the claims, the word“comprising” does not exclude other steps or elements, and the indefinite article“a” or“an” does not exclude a plurality.

Any reference signs in the claims should not be construed as limiting the scope of the invention.

Elements and aspects discussed for or in relation with a particular embodiment may be suitably combined with elements and aspects of other embodiments, unless explicitly stated otherwise. Thus, 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.

The terms“comprise” and“include” as used in this text will be understood by a person skilled in the art as covering the term“consist of’. Hence, the term“comprise” or “include” may in respect of an embodiment mean“consist of’, but may in another embodiment mean“contain/have/be equipped with at least the defined species and optionally one or more other species”.

Notable aspects of the invention can be summarized as follows. In the context of anti-bio fouling, a system is provided that is designed to realize an anti-bio fouling effect on at least a grating 21 of a grating unit 20 for use with a marine object, the grating unit 20 being configured for allowing fluid to pass therethrough and the grating 21 being adapted to prevent items from passing through the grating unit 20 along with the fluid, the system including at least one light source 10 that is configured to emit anti-bio fouling light, and the system being arrangeable with respect to the grating 21 for emitting the anti-bio fouling light towards, in and/or away from the grating 21 in an activated state of the system. The system may be arrangeable with respect to the grating 21 at one side of the grating 21 only, or at two different sides of the grating 21. One or more components of the system may be provided as integral parts of the grating unit 20 and/or the design of the grating 21 may have aspects promoting distribution of the anti-bio fouling light in/on the grating 21.