WO2018199767A1

WO2018199767A1 - An underwater cleaning device and apparatus

Info

Publication number: WO2018199767A1
Application number: PCT/NO2018/050103
Authority: WO
Inventors: Trond Sivertsen
Original assignee: Mpi As
Priority date: 2017-04-28
Filing date: 2018-04-16
Publication date: 2018-11-01
Also published as: NO20180516A1; NO20170713A1; NO343072B1

Abstract

An underwater cleaning device comprises a disc member (100; 110; 120; 130; 140; 150) rotatably connected to a mounting member (101) and having a first disc side (104a) arranged to face a submerged object to be cleaned. The disc member comprises a plurality of nozzles (105) fluidly connected to conduits (106) configured for supply of pressurized liquid, arranged on the first disc side (104a) and configured for discharging pressurized liquid tangentially with respect to the disc member and away from the disc first side (104a); causing a disc rotation (R). At least one through-going opening (103; 107; 122) is arranged between the disc first side (104a) and an opposite disc second side (104b), and a plurality of blade members (111; 121; 131) are arranged radially on the disc second side (104b). The openings may be one or more circumferential slits and/or a circumferential row of holes arranged concentrically on the disc member. An underwater cleaning apparatus (1) one or more disc members (100; 110; 120; 130; 140; 150). The cleaning apparatus is useful for cleaning a seine or net in a net pen.

Description

An underwater cleaning device and apparatus Field of the invention

The invention concerns an underwater cleaning device as set out by the preamble of claim 1, and an underwater cleaning apparatus as set out by the preamble of claim 11. The invention is particularly useful for cleaning submerged seines, nets or cages in net pens in a fish farming plant.

Background of the invention

A ship's hull which is subjected to marine organisms is prone to barnacle growth and general fouling, making the hull surface rough and uneven. This leads to greater friction resistance when the ship is propelled through the water, which in turn means a significant increase in fuel consumption. Frequent hull cleaning is therefore required, both from economic and environmental points of view.

Marine fouling is also a problem in the fish farming industry, where the fouling on submerged seines (or cages or nets) in the fish farming plant's net pens restricts water flow into and out of the net pen hence causes oxygen depletion in the water inside the net pen. Net pens have traditionally been cleaned by divers which have utilized high- pressured water jets to remove the fouling, more sophisticated devices have been developed.

The prior art includes WO 2005/044657 (Andersen, et al.), which describes a device for cleaning submerged surfaces, such as ships' hulls. The device comprises a rotary disc having nozzles for discharging pressurized liquid against the surface to be cleaned. The nozzles are mounted obliquely in relation to the rotational axis of the rotary disc and are arranged to be supplied with pressurized liquid through a hollow spindle that is concentric with the rotational axis.

The prior art also includes KR 2008/0093536 (Park, et al.), which describes an underwater robot for cleaning and inspecting a ship's hull. The robot comprises wheels for rolling on the submerged hull, vertical/horizontal thrusters to induce movement in the vertical and horizontal directions, and a water jet spraying device. The robot wheels are driven by motor, whereby the robot is driven along the ship hull. The robot is remotely controlled from a console (above water), via an umbilical cable.

The prior art also includes US 4 462 328 (Oram), which describes a carriage with wheels for travelling along the ship hull and having a plurality of cleaning nozzles and a reactor nozzle aligned to produce a reactive force which opposed the force component of the cleaning nozzles which tends to urge the carriage away from the hull of a ship.

The prior art also includes WO2012/074408 A2 (Andersen), which describes a device for cleaning of ship's hulls or other submerged surfaces. The device comprises a cleaning disc arranged in a housing, thus forming a cavity between the cleaning disc and the housing. The cleaning disc is rotatably supported by a spindle and configured for rotation about a rotational axis by a drive motor. The cleaning disc has one side facing the surface to be cleaned and comprises a plurality of nozzles for discharging liquid under pressure against the surface. The nozzles are arranged such that the cleaning liquid is ejected more or less radially from the disc, and inclined downwardly, out from the housing such that the cleaning liquid will impinge the adjacent hull surface which is being cleaned. The cleaning disc comprises a number of holes, extending between the disc's inward side and its outward side (the outward side being the side facing the hull when the unit is in operation) and arranged at regular intervals around the disc. When the cleaning disc is rotating, the holes serve as liquid transfer ports, transporting liquid from the disc's outward side to the inward side and thus into the cavity, from which the liquid is evacuated through designated outflow openings.

The prior art also includes US 4 926 775 (Andorsen), which describes a cleaning apparatus for use under water, particularly for cleaning vertical surfaces which are fouled by marine organisms. One or more nozzles for spraying water at high pressure at a surface to be cleaned are arranged on a rotary disc-shaped unit where the rotation axis is intended to be generally perpendicular to the surface which is to be cleaned. The nozzles are obliquely located in a circular plane so that the rotating unit can rotate. Beyond the periphery of the rotating unit there is a casing which forms an annular chamber with an outlet which is at least partly directed away from the surface which is to be cleaned. The annular chamber is formed from two generally cylindrical or truncated conical casing units which are positioned at a radial distance from each other with their internal ends concentric with respect to the nozzle holder.

The prior art also includes WO2010/005314 Al (Sivertsen), which describes a device for maneuvering and propulsion of a submerged cleaning apparatus. The cleaning apparatus is intended for removal of marine fouling from submerged marine

installations, such as seines and pens in fish farming plants. The device comprises an induction part adapted to supply of a fluid at high pressure, a nozzle with an inlet for supply of the fluid at high pressure, and a tubular body with an induction side and an outlet where the nozzle is arranged close to the induction side. Such water jet can be combined with a number of water jet devices which is mounted to a front board for an apparatus for removal of marine fouling from marine installations. The front board will typically be provided with two or more rotating cleaning units. The rotating cleaning units are propelled by high pressure water, preferably from the same high pressure source as the water jet devices. A system comprising the front board, two or more rotating cleaning units and at least a water jet device is referred to as "the rotor apparatus" for cleaning of marine installations.

The prior art also includes JP 2001-276754 (Ozaka), which describes a submersible cleaning robot equipped with a cleaning nozzle unit which jets high-pressure water to a cultured fish net from the bottom of a robot casing. A cleaning nozzle unit is fitted to the lower end of a rotary shaft supported at a rotary joint. Further, a propeller is fitted to the upper end of the rotary shaft. The cleaning nozzle unit, the rotary shaft and the propeller are integrally rotated by the jet reaction of the high-pressure water from the cleaning nozzle unit. Thus, the propulsion force of the robot toward the cultured fish net is obtained by the rotation of the propeller.

The prior art also includes WO 2007/105303 Al (Osaka, et al.), which describes an underwater cleaning robot by jetting high-pressure water from a cleaning nozzle unit to the surface of an object while moving along the surface. The cleaning nozzle unit is attached to a rotating shaft rotatably provided at a robot body and is constructed so as to rotate together with the rotating shaft by reaction of jetting of the high-pressure water. A propeller is attached to the rotating shaft and rotates as the rotating shaft rotates, producing propulsion force for pressing the robot body against the surface of the object. The leading edges of the propeller blades are formed to have a sweepback angle that prevents twining of foreign objects on the propeller.

The prior art also includes WO 2013/047061 Al (Osaka, et al.), which describes an underwater cleaning robot having cleaning nozzle units rotatably provided on a lower part of a robot body, and a travel device for moving the robot body. The travel device includes first travel means provided on the left and right of the robot body, and second travel means respectively provided frontward and backward of the first travel means and located above bottom ends of the first travel means.

It is an object of this invention to provide cleaning apparatus and vehicle which is more efficient and simpler to operate that those of the prior art, particularly in cleaning nets and seines of a fish pen.

Summary of the invention

The invention is set forth and characterized in the main claim, while the dependent claims describe other characteristics of the invention.

It is thus provided an underwater cleaning device, comprising a rotatable member having a first side arranged to face a submerged object to be cleaned; the rotatable member further comprising a plurality of nozzles fluidly connected to conduits configured for supply of pressurized liquid; said nozzles being arranged on said first side and configured for discharging pressurized liquid, causing a rotation; characterized by a plurality of blade members arranged and configured to provide a thrust force towards said submerged object.

In one embodiment, the rotatable member is a disc member rotatably connected to a mounting member and having a first disc side arranged to face a submerged object to be cleaned; the disc member further comprising a plurality of nozzles fluidly connected to conduits configured for supply of pressurized liquid; said nozzles being arranged on the first disc side and configured for discharging pressurized liquid tangentially with respect to the disc member and away from the disc first side causing a disc rotation;

characterized by at least one through-going opening between the disc first side and an opposite disc second side, and a plurality of blade members arranged radially on the disc second side. In one embodiment, the at least one opening comprises at least one circumferential slit, arranged concentrically on the disc member. In one embodiment, the at least one opening comprises at least circumferential row of holes, arranged concentrically on the disc member. These two embodiments may be combined. The blade members may be vanes or turbine blades. The holes may have an inclined bore geometry, with a water inlet opening on the disc first side and an outlet opening on the disc second side, whereby ambient water will be forced into the inlet opening and ejected out of the outlet opening when the disc member is rotating.

In one embodiment, a plurality of vanes are arranged in the circumferential slit.

In one embodiment, the rotatable member comprises an impeller, a thrust propeller, or a turbine. The rotatable member may be arranged in a duct.

It is also provided an underwater cleaning apparatus, opposite first and second sides, where the first apparatus side is configured for facing a submerged object to be cleaned; thruster means arranged and controllable for moving the cleaning apparatus relative to said object; characterized by one or more underwater cleaning devices according to the invention, arranged on the cleaning apparatus and having the first disc side arranged to face said submerged object to be cleaned.

In one embodiment, the thruster means comprise one or more thruster modules, each comprising one or more thruster units configured to be powered by pressurized water. In one embodiment, the thruster means comprise one or more electrical thrusters.

The underwater cleaning apparatus comprises in one embodiment traction means configured for interaction with said object. In one embodiment, the underwater cleaning apparatus comprises designated receptacles having a shape corresponding to the shape of a thruster module.

In one embodiment, the thruster means comprises water deflector means forming a slot in the region of a thruster means outlet, said slot configured for mixing water ejected from the thruster with ambient water.

The invented underwater cleaning apparatus preferably has a rectangular, plate-like shape. It is not as tall as some of the prior art cleaning apparatuses, partly due to the fact that the propeller blades are assembled on (and thus integrated with) the cleaning disc. This provides improved maneuverability in the water and easier handling during deployment, retrieval and transportation.

The disc's through-going openings supply the water to the propeller blades located immediately adjacent to the through-going openings, i.e. transporting water from the first disc side to the second disc side, and thus contribute to increasing the suction effect and hence the movement towards the object to be cleaned, compared to the prior art discs.

The underwater cleaning apparatus is particularly useful for cleaning a seine or net in a net pen.

Brief description of the drawings

These and other characteristics of the invention will become clear from the following description of embodiments of the invention, given as non-restrictive examples, with reference to the attached schematic drawings, wherein:

Figure 1 is a perspective view of a first embodiment of the underwater cleaning apparatus according to the invention;

Figure 2 corresponds to figure 1, but in this figure certain parts have been removed for illustration purposes;

Figure 3 is another perspective view of the cleaning apparatus illustrated in figures 1 and 2;

Figure 4 is a partly exploded view of the cleaning apparatus illustrated in figure

2;

Figure 5 is another perspective view of the cleaning apparatus illustrated in figure 4

Figure 6 corresponds to figure 4, but is a further exploded view and certain parts have been removed for illustration purposes; Figure 7 corresponds to figure 6, but illustrate only the traction components (all other components having been removed for illustration purposes, and the right-hand side of the figure is an exploded view);

Figure 8 corresponds to figure 6, but even more parts have been removed to illustrate internal structures and components;

Figure 9 corresponds to figure 8, but even more parts have been removed to illustrate internal structures and components;

Figure 10 is a perspective view of a second embodiment of the underwater cleaning apparatus according to the invention;

Figure 11 corresponds to figure 10, but shows a thruster module removed from its receptacle;

Figure 12 is a perspective view of a third embodiment of the underwater cleaning apparatus according to the invention;

Figure 13 is a partly exploded view of the cleaning apparatus illustrated in figure

12;

Figure 14 is a perspective view of a first embodiment of a cleaning disc according to the invention;

Figure 15 corresponds to figure 14, but is a see-through drawing; illustrating internal parts and geometries of the cleaning disc;

Figure 16 is a perspective view of the embodiment illustrated in figure 14, and illustrates that side of the disc which will be facing the object to be cleaned when the disc is in use for its intended purpose;

Figure 17 is a perspective view of a second embodiment of a cleaning disc according to the invention;

Figure 18 is a perspective view of the embodiment illustrated in figure 17, and illustrates that side of the disc which will be facing the object to be cleaned when the disc is in use for its intended purpose; Figure 19 is a perspective view of a third embodiment of a cleaning disc according to the invention;

Figure 20 is a perspective view of the embodiment illustrated in figure 19, and illustrates that side of the disc which will be facing the object to be cleaned when the disc is in use for its intended purpose;

Figure 21 is a perspective view of a fourth embodiment of a cleaning disc according to the invention;

Figure 22 is a partly exploded view of the embodiment illustrated in figure 21;

Figure 23 is a perspective view of a fifth embodiment of a cleaning disc according to the invention;

Figure 24 is a perspective view of a sixth embodiment of a cleaning disc according to the invention;

Figure 25 is a perspective view of the embodiment illustrated in figure 24, and illustrates that side of the disc which will be facing the object to be cleaned when the disc is in use for its intended purpose;

Figure 26 and is a perspective view of a seventh embodiment of a cleaning disc according to the invention;

Figure 27 is a perspective view of the embodiment illustrated in figure 26, and illustrates that side of the disc which will be facing the object to be cleaned when the disc is in use for its intended purpose;

Figure 28 is a perspective view of a variant of the embodiment illustrated in figure 26, in which the slits are not furnished with vanes;

Figure 29 is a perspective view of an embodiment of a thruster module according to the invention, incorporating deflector plates;

Figure 30 is a sectional view of the embodiment of the thruster module illustrated in figure 29; Figure 31 is a perspective view of an embodiment of the underwater cleaning apparatus having three thruster modules of the kind illustrated in figures 29 and 30;

Figures 32a-e are perspective views of other embodiments of the invented cleaning disc;

Figure 33a is a perspective view of yet an embodiment of a cleaning disc according to the invention, wherein an impeller has been fitted to that side of the disc which will be facing away from the object to be cleaned when the disc is in use for its intended purpose;

Figure 33b is another perspective view of the embodiment illustrated in figure 33a, illustrating that side of the disc which will be facing the object to be cleaned when the disc is in use for its intended purpose;

Figure 34a is a perspective view of an embodiment of a cleaning thrust propeller according to the invention, illustrating that side of the propeller which will be facing away from the object to be cleaned when the propeller is in use;

Figure 34b is another perspective view of the embodiment illustrated in figure 34a, illustrating that side of the thrust propeller which will be facing the object to be cleaned when the turbine is in use;

Figures 35a and 35b are perspective views of a cleaning disc arranged inside a duct;

Figures 35c and 35d are perspective views of the cleaning disc and duct configurations illustrated in figures 35a and 35b, but a portion of the duct has been removed to better illustrate the cleaning disc;

Figure 36a is a perspective views of an embodiment of the cleaning disc; and figure 36b is a perspective view of the cleaning disc arranged inside a duct, a portion of the duct having been removed to better illustrate the cleaning disc;

Figures 37a and 37b are perspective views of a cleaning disc and impeller configuration, arranged inside a duct, and a portion of the duct having been removed to better illustrate the cleaning disc and impeller; Figures 38a and 38b are perspective views of a cleaning turbine arranged inside a duct, and a portion of the duct having been removed to better illustrate the cleaning turbine;

Figures 39a and 39b correspond to figures 38a and 38b, but a portion of the duct has not been removed; and

Figures 40a and 40b are perspective views of a cleaning thrust propeller arranged inside a duct.

Detailed description of a preferential embodiment

The following description will use terms such as "horizontal", "vertical", "lateral", "back and forth", "up and down", "upper", "lower", "inner", "outer", "forward", "rear", etc. These terms generally refer to the views and orientations as shown in the drawings and that are associated with a normal use of the invention. The terms are used for the reader's convenience only and shall not be limiting.

Referring initially to figures 1, 2 and 3, the invented underwater cleaning apparatus 1 has in the illustrated embodiment a flat, rectangular and plate-like, shape. For the purpose of this description, that side of the cleaning apparatus 1 which will be facing the object to be cleaned (i.e. seine or net in a net pen, or a submerged surface) will be referred to as the first, or lower, side 20, whereas the opposite side will be referred to as the second, or upper, side 21. The nominal direction of travel for the underwater cleaning apparatus 1 when cleaning a submerged object is indicated in figure 1 by the arrow M, but it should be understood that the apparatus 1 may be moved in other directions. For the purpose of this description, reference numbers 22 and 23 designate a cleaning apparatus forward region and rear region, respectively.

The cleaning apparatus comprises rounded bumpers 11 and traction belts 2, arranged on opposite edges of the apparatus. The traction belts are shaped to interact with the object to be cleaned (e.g. having knobs, ridges or serrations; not shown), such that the cleaning apparatus can be "driven" on the object. This feature is particularly advantageous when cleaning flexible and moving nets hanging in the water. The direction of travel M may be in any direction on the net. The traction belts are driven by hydraulic or electric motors (not shown in figure 6). Roller cylinders 3 are arranged in the forward and rear regions 23, 24, as illustrated, and serve to prevent the cleaning apparatus from becoming snagged by the net or seine. In the illustrated embodiment, the roller cylinders are hollow, open cylinders, but it should be understood that the roller cylinders may be solid members, for example comprising a buoyant material. The interconnection between the roller cylinders 3, traction belts 2 and the motors is described below with reference to figure 7.

Arranged on the cleaning apparatus' upper side 21 are three covers 9, each having three ports 9a, and three grilles 10. The ports 9a provide outlets from respective thrusters inside the apparatus (described below). The grilles 10 are arranged in front of outlets from respective cleaning disks 100 that are rotatably arranged on the cleaning apparatus' lower side 20 (see figure 2). It should be understood the cleaning apparatus may comprise fewer or more cleaning discs and thrusters than the number illustrated. The rotatable cleaning discs 100 are arranged on the cleaning apparatus' lower side 20. The cleaning discs, as well as various embodiments, are described below. Reference numbers 12 designate inlet grilles for the embedded thrusters, described below.

A camera 4 is arranged on the upper side 21, and connected to the cleaning apparatus 1 via a centrally mounted support structure 24 having a suitable rake, whereby the camera is arranged toward and above the rear region 23. Therefore, in use, the operator is able to see the forward portion of the cleaning apparatus, which enhances operator control. Lights 26 (which may be rotatable) are arranged on the cleaning apparatus forward portion. The support structure 24 is provided with holes 33 that may be used as attachment points for a lifting cable (not shown).

The cleaning apparatus 1 is remotely controlled via an umbilical or bundle 25, comprising flexible hoses for feeding liquid (preferably water) at high pressures to thrusters and the cleaning discs and hydraulic oil to the motors, power cables to the motors 34 (if electric), camera and lights, signal cables, and other control cables as required. Such umbilicals and cables and control means are well known in the art and need therefore not be described in more detail. Reference number 5 designates a connector interface for the umbilical or bundle 25. In a normal mode of operation, the umbilical or bundle 25 is connected to power and control facilities (not shown) located in e.g. a boat on the water surface. On the cleaning apparatus, the high-pressure liquid is fed to the thrusters via hoses 25a and to the cleaning discs via piping 25b.

Referring now to figures 4 and 5, the cleaning apparatus 1 comprises thruster modules 13 that each are powered by high-pressure water (e.g. 300 bar) through hoses 25a. In the illustrated embodiment, each thruster module 13 comprises three water jet thrusters 13a (see figure 5) with respective thruster outlets 9a. The thruster may be any thruster known in the art, but may conveniently be of the kind described in the above mentioned WO2010/005314 Al (Sivertsen). Fewer or more thrusters than illustrated may be used. The thruster module 13 is formed as a replaceable module and the cleaning apparatus comprises corresponding receptacles 14, each having a shape complementary to that of the thruster module and extending through the apparatus body. This configuration allows fast and efficient replacement of thruster modules. When the thruster module is installed in a receptacle 14, the thruster cover 9 is almost flush with the upper side 21 and the thruster inlet grille 12 is almost flush with the lower side 20.

Referring to figures 29, 30 and 31, the thruster module 13' is in one embodiment furnished with water deflector plates 30, 31, arranged on the thruster cover 9 via a base structure 32. A rear deflector plate 31 is arranged behind (downstream of) the thruster outlet 9a and extend down to the thruster cover 9. A forward deflector plate 30 is arranged in front of the thruster outlet 9a and a distance above the thruster cover 9, thereby forming a slot S between the forward deflector plate 30 and the thruster cover 9 and between the forward deflector plate 30 and rear deflector plate 31. When the thruster is operating and the cleaning apparatus is in operation as described above, water W_e is ejected from the thruster outlet and is mixed with ambient water Wi which is drawn in under the forward deflector plate 30; the resultant water flow W escaping through the rearward end of the slot S.

Referring to figures 4, 6 and 9, each cleaning disc 100 is supported in the cleaning apparatus by a disc mount 101 connected to a girder 19a or 19b(see figures 4), which is described in more detail below. Figures 8 and 9 also illustrate the main structural components of the cleaning apparatus. A base frame 15, which for example may be formed of a steel material, or a light-weight material such as aluminium, supports two parallel beams or girders 19a,b, extending between the base frame short ends. The girders provide support for the disk mounts 101. A buoyant material 17 (e.g.

"Divinycell") is arranged inside the base frame, between the base frame walls and girders. Ducts 17 (see figures 6 and 8) are formed through the buoyant material; one duct per cleaning disc. Upper and lower panels 16a,b, which comprise cut-out portions corresponding to the shapes of the above mentioned thruster modules and inlet grilles, are fastened to the upper and lower sides of the base frame, respectively. The panels hold the buoyancy material in place and contributes to the overall torsional stiffness of the cleaning apparatus.

One embodiment of the traction system will now be described with reference to figure 6. Two motors (here: hydraulic) 34a,b have respective connection ports 5 for connection to an umbilical. Each motor 34a,b is arranged in a respective support bracket 36a,b which also supports one end of a respective roller cylinder 3d,c. Each roller cylinder 3d,c is rotatably connected at its other end to respective first belt drive wheels 37a,b (only 37a shown in figure 7). Each traction belt 2a,b is rotatably supported and driven by respective first drive wheels 37a,d, and in turn drive respective second drive wheels 37c,d (only 37c shown in figure 7). Each second drive wheel 37c,d is connected to a first end of respective roller cylinders 3b, a. The second ends of the roller cylinders 3b, a are rotatably supported by a support bracket 35. Therefore, the first motor 34a will drive the (rear) roller cylinder 3d, the traction belt 2a, and the (forward) roller cylinder 3b. The second motor 34b will drive a corresponding set of roller cylinders and belt on the other apparatus right-hand side ( the left side in figure 7).

Other embodiments of the underwater cleaning apparatus according to the invention are illustrated in figures 10, 11, 12 and 13 and will be described in the following. Only differences with respect to the first embodiment (figures 1-9) are described.

In the embodiments illustrated in figures 10-13, the thrusters are bidirectional thrusters 27a, comprising a respective propeller powered by an electric motor. Figure 13 illustrates the electric thruster 27a, upper cover 27 and lower cover 27b. Compared to the unidirectional high-pressure water jet thrusters 13a described above, the

bidirectional thrusters 27a provide the cleaning apparatus 1 with improved

maneuverability, allowing it to move in the water as a conventional remotely operated vehicle (ROV). It should be understood that water deflector plates 30, 31, described above with reference to figures 29-31, may be arranged on the thruster cover 27.

The thruster assembly 27, 27a,b may be formed as a replaceable thruster module 27c as illustrated in figure 11 (corresponding to the thruster module 13 described above with reference to figure 4), fitting into the receptacle 14.

Figures 12 and 13 illustrate an embodiment in which optional respective thruster pods 6 are arranged on support structures 7 on both sides of the camera. Reference number 6' indicates an exploded view of a thruster pod, revealing also an electric thruster 27a.

In the embodiment illustrated in figures 12 and 13, the traction belts (reference number 2 in figure 10) have been replaced by free-wheeling inline rollers 28. Also, the roller cylinders (reference number 3 in figure 1) have been replace by a plurality of freewheeling rollers 29. It should be understood, therefore, that the underwater cleaning apparatus may use driven traction belts 2 and roller cylinders 3 (figures 10 and 11) or the free-wheeling rollers shown in figures 12 and 13.

Various embodiments of the cleaning disc will now be described with reference to figures 14 to 28.

Figures 14, 15 and 16 illustrate a cleaning disc 100 according to a first embodiment. The cleaning disc 100 is connected to a spindle which is rotatably supported by a disc mount 101 (internal bearings not shown). The disc mount 101 is configured for connection to the girders 19a,b as described above. The cleaning disc may be made of polyoxymethylene (POM) or any other suitable material, and manufactured according to processes that are well known in the art. As illustrated in figures 14 and 15, the disc comprises internal and radially extending fluid conduits 106 which are connected to the above mentioned pipes 25b via the disc mount 101. Each fluid conduit 106 is fluidly connected to a nozzle 105, which is arranged in the lower, or first, disc side 104a (see figure 14). This lower disc side 104a is arranged on the cleaning apparatus lower side 20 (see figure 3) when the disc is assembled as described above. The nozzles 105 are arranged with a downward inclination (i.e. away from the lower side 104a), and oriented tangentially on the disc 100. In use, therefore, pressurized water is ejected tangentially and downwardly, generating a thrust force T as indicated in figure 16. This causes the disc to rotate in the direction R. The high-pressure water jet being ejected from the nozzle therefore serve to rotate the disc and to clean the object against which the cleaning apparatus is being arranged. Such cleaning discs are well known in the art and need therefore not be described in more detail here. When the cleaning apparatus is used for cleaning a net pen, the marine fouling is removed from the net by the water jet, and forced into the seine or net where it will sink toward the net pen bottom.

The water jet will also tend to generate a reaction force F (see figure 14), i.e. pushing the cleaning apparatus away from the net pen. In order to mitigate this tendency and in effect provide the cleaning disc 100 with a thrust component towards the net pen (or other object that is being cleaned), the cleaning disc is provided with a number of through-going holes 103, arranged at circumferentially and at regular intervals on the disc, in the vicinity of the disc periphery. The holes 103 have an inclined bore geometry, with an inlet opening 103a and an outlet opening 103b arranged in a staggered relationship on opposite sides of the disc. In operation, when the disc is rotating, ambient water will be forced into the inlet opening 103a (on the disc first side 104a) and ejected out of the outlet opening 103b on the disc second side 104b. The holes 103 are therefore in effect thrust-augmenting devices.

Figures 17 and 18 illustrate a cleaning disc 110 according to a second embodiment. The cleaning disc 110 corresponds to the cleaning disc 110 of the first embodiment, but comprises in addition three (only two shown) propeller blades 111 arranged at regular intervals on the second disc side 104b (opposite to the first disc side 104a), radially extending from and connected to the spindle via a boss 112. Each blade 111 has a root- to-tip twist as shown in the figures, and the tip is preferably arranged in the vicinity of an outlet opening 103b. When the disc 110 is rotating, the blades 111 provide an additional thrust component towards the net pen (or other object that is being cleaned). It should be understood that the blades 111 may be mounted at inclinations different than those illustrated, thereby adjusting the propeller pitch.

Figures 19 and 20 illustrate a cleaning disc 120 according to a third embodiment. The cleaning disc 120 corresponds to the cleaning disc 110 of the first embodiment, but comprises in addition a second group of circumferentially arranged holes 122. The holes 122 have an internal bore geometry that correspond to that of the holes 103. Also, a number of propeller blades 121 are arranged on the second disc side 104b and connected to the disc via a support ring 123. In the illustrated embodiment, each blade 121 is arranged at a respective outlet opening 103b. When the disc 120 is rotating, the blades 121 provide an additional thrust component towards the net pen (or other object that is being cleaned). It should be understood that the blades 121 may be mounted at inclinations different than those illustrated, thereby adjusting the propeller pitch.

Figures 21 and 22 illustrate a cleaning disc 130 according to a fourth embodiment. The cleaning disc 130 corresponds to the cleaning disc 110 of the first embodiment, but comprises in addition a number of propeller blades 131 arranged on the second disc side 104b and connected to the disc via a support ring 133. When the disc 130 is rotating, the blades 131 provide an additional thrust component towards the net pen (or other object that is being cleaned). The support ring 133 may be split in part-rings 133a,b as shown in figure 22, whereby individual blades 131 may be replaced. It should be understood that the blades 131 may be mounted at inclinations different than those illustrated, thereby adjusting the propeller pitch.

Figure 23 illustrates a cleaning disc 140 according to a fifth embodiment. The cleaning disc 140 corresponds to the cleaning disc 130 of the third embodiment, but does not have through-going holes. The cleaning disc 140 comprises two circular slits 107, which serve to reduce the disc surface area and allow a passage of water from the first disc side 104a to the second disc side 104b. The slits are in effect made up of two concentric rings interconnected and connected to the spindle via spoke supports 152. The spoke supports hold the water supply conduits 106 (not shown in figure 23), described above with reference to figure 15. The increased water flow (through the slits) will contribute to the efficiency of the propeller blades 131. Thus, when the disc 140 is rotating, the blades 131 will yield an additional thrust component towards the net pen (or other object that is being cleaned). It should be understood that the blades 131 may be mounted at inclinations different than those illustrated, thereby adjusting the propeller pitch.

Figures 24 and 25 illustrate a cleaning disc 150 according to a sixth embodiment. The cleaning disc 150 comprises two concentrically arranged circular slits 107, in effect made up of two concentric rings interconnected and connected to the spindle via spoke supports 152. The spoke supports hold the water supply conduits 106 (not shown in figures 24 and 25), described above with reference to figure 15. The slits 107 serve to reduce the disc surface area and allow a passage of water from the first disc side 104a to the second disc side 104b. This increased water flow (through the slits) will contribute to the efficiency of the propeller blades 111. Thus, when the disc 150 is rotating, the blades 111 will yield an additional thrust component towards the net pen (or other object that is being cleaned). It should be understood that the blades 111 may be mounted at inclinations different than those illustrated, thereby adjusting the propeller pitch. Also, although not illustrated, a variant of the cleaning disk 150 without the blades 11 1 is conceivable.

Figures 26 and 27 illustrate a cleaning disc 160 according to a seventh embodiment. The cleaning disc 160 comprises two concentrically arranged circular slits 107, in effect made up of two concentric rings interconnected and connected to the spindle via spoke supports 152. The slits 107 serve to reduce the disc surface area and allow a passage of water from the first disc side 104a to the second disc side 104b. A plurality of vanes 161 are arranged at an oblique angle in the slits, thereby in effect forming a turbine. Thus, when the disc 160 is rotating, the vanes 161 will yield an additional thrust component towards the net pen (or other object that is being cleaned).

Figure 28 illustrates a cleaning disc 160', which is a variant of the cleaning disc 160, but in which is the concentric slits 107 are open, without vanes.

Figures 32a-e illustrate other embodiments of the invented cleaning disc lOOa-f, having various configurations of through-going holes or openings 103a-c. The openings may be circular, oval, curved; or constitute sectors 103c (see figure 32e).

In figures 33a,b an impeller 200 with blades 201 has been fitted to that side of the cleaning disc lOOd which will be facing away from the object to be cleaned when the disc is in use for its intended purpose. It should be understood that the impeller may be fitted to other embodiments of the cleaning disc than the one shown in figures 33a,b.

Figures 34a,b illustrate a cleaning thrust propeller 210, which may replace (substitute) the cleaning discs described above. The thrust propeller 210 comprises propeller blades 211 connected to a hub 212 which is rotatably supported in a manner similar to that of the cleaning discs. Towards the free end (tip) of each blade 210, cleaning nozzles 105 are arranged, fluidly connected to a source of pressurized fluid (not shown) and operated as described above with reference to the cleaning discs. In use, the rotating propeller will generate a thrust force towards the object to be cleaned.

Figures 35a-d are perspective views of a cleaning disc 100a arranged inside a duct 38. In figures 35c and 35d a portion of the duct has been removed to better illustrate the cleaning disc. It should be understood that duct mat be fitted with other embodiments of the cleaning disc than the one shown in figures 35a-d. The duct 38 may be installed in the through-going duct 37 (see figure 8), or may be integrated with the through-going duct.

Figure 36b is a perspective view of the cleaning disc lOOf arranged inside a duct (a portion of the duct has been removed to better illustrate the cleaning disc). Figures 37a,b illustrate similar configurations.

Figures 38a,b and 39a,b illustrate a cleaning turbine 220 arranged inside a duct 38. Figures 40a,b are perspective views of a cleaning thrust propeller 210 arranged inside a duct 38.

In all of the above mentioned embodiments in which a rotatable cleaning disc, turbine or propeller has been arranged inside a duct, a gap G is formed between the inner duct wall and the rotatable member (see figures 38b, 39b, 40b).

It should be understood that the embodiments of the disc described above are examples, and that the through-going holes, number and form of propeller blades, and slits may be combined in ways other than those illustrated. As such, the invention shall not be limited to the number of holes, slits or propeller blades shown in the drawings.

It should also be understood that the underwater cleaning apparatus 1 may be equipped with any one of the embodiments of the disc, turbines, propellers and impellers described above, as well as any combination of these. Discs may be arranged on the cleaning apparatus 1 to the be counter-rotating, in which case the through-going hole geometry and propeller blade pitch will be arranged in opposite directions. In a practical application, for cleaning a net pen, the disc diameter is typically 600 mm and rotate at about 300 to 400 RPM. The pressure supplied to the cleaning nozzles is on the order of 250 to 300 bar. The invention shall, however, not be limited to such values. The invented cleaning apparatus is particularly useful for cleaning flexible nets and seines, for example in a net pen.

Claims

1. An underwater cleaning device, comprising a rotatable member (100; 110; 120; 130; 140; 150; 160; 200; 210; 220) having a first side arranged to face a submerged object to be cleaned; the rotatable member further comprising a plurality of nozzles (105) fluidly connected to conduits (106) configured for supply of pressurized liquid; said nozzles being arranged on said first side and configured for discharging pressurized liquid; causing a rotation (R);

characterized by

a plurality of blade members (111; 121; 131; 201; 211; 221) arranged and configured to provide a thrust force towards said submerged object.

2. The underwater cleaning device of claim 1, wherein the rotatable member is a disc member (100; 110; 120; 130; 140; 150; 160) rotatably connected to a mounting member (101) and having a first disc side (104a) arranged to face a submerged object to be cleaned; and said nozzles being arranged on the first disc side (104a); and the disc member comprising at least one through-going opening (103; 107; 122) between the disc first side (104a) and an opposite disc second side (104b), and a plurality of blade members (111; 121; 131) arranged radially on the disc second side (104b).

3. The underwater cleaning device of claim 2, wherein the at least one opening comprises at least one circumferential slit (107), arranged concentrically on the disc member.

4. The underwater cleaning device of claim 2 or claim 3, wherein the at least one opening comprises at least circumferential row of holes (103; 122), arranged concentrically on the disc member.

5. The underwater cleaning device of any one of claims 1-4, wherein the blade members are vanes (121).

6. The underwater cleaning device of any one of claims 1-5, wherein the blade members are turbine blades (111; 131).

7. The underwater cleaning device of any one of claims 4-6, wherein the holes (103; 122) have an inclined bore geometry, with a water inlet opening (103a) on the disc first side (104a) and an outlet opening (103b) on the disc second side (104b), whereby ambient water will be forced into the inlet opening (103a) and ejected out of the outlet opening (103b) when the disc member is rotating.

8. The underwater cleaning device of claim 3, wherein a plurality of vanes (161) are arranged in the circumferential slit (107).

9. The underwater cleaning device of claim 1, wherein the rotatable member comprises an impeller (200), a thrust propeller (210), or a turbine (220).

10. The underwater cleaning device of any one of claims 1-9, wherein the rotatable member is arranged in a duct (38; 37).

11. An underwater cleaning apparatus (1) comprising:

- opposite first and second sides (20, 21), where the first apparatus side (20) is configured for facing a submerged object to be cleaned;

- thruster means (13; 27c) arranged and controllable for moving the cleaning apparatus relative to said object;

characterized by

- one or more underwater cleaning devices according to any one of claims 1-10, arranged on the cleaning apparatus (1) and having the first side (104a) arranged to face said submerged object to be cleaned.

12. The underwater cleaning apparatus of claim 11, wherein the thruster means comprise one or more thruster modules (13; 13'), each comprising one or more thruster units (13a) configured to be powered by pressurized water.

13. The underwater cleaning apparatus of claim 11, wherein the thruster means (27c) comprise one or more electrical thrusters (27a).

14. The underwater cleaning apparatus of any one of claims 11-13, further comprising traction means (2) configured for interaction with said object.

15. The underwater cleaning apparatus of any one of claims 11-14, further comprising designated receptacles (14) having a shape corresponding to the shape of a thruster module (13; 27c).

16. The underwater cleaning apparatus of any one of claims 11-15, wherein the thruster means comprises water deflector means (30, 31) forming a slot (S) in the region of a thruster means outlet (9a), said slot configured for mixing water (W_e) ejected from the thruster with ambient water (Wi).

17. The underwater cleaning apparatus of any one of claims 11-16, wherein the apparatus has a rectangular, plate-like shape.

18. Use of the cleaning apparatus according to any one of claims 11-17 for cleaning said submerged object, wherein the object is a seine or net in a net pen.