C l a i m s
1. A cleaning device (2) for a surface of an underwater structure (22) , the cleaning device (2) comprising:
- a support structure (4) ;
5 - at least one cleaning roller (6, 8) which is rotatable about its longitudinal axis, which is provided with external cleaning elements (12, 14), and which is fastened to the support structure (4) ;
- at least one rotary device (16, 18) connected to saido cleaning roller (6, 8) for rotation thereof, insofar as such rotation under water (20) will generate water currents emanating from said cleaning roller (6, 8) ; and
- at least one flow diverter (24, 26) including a diverter surface (28, 30) structured for directionals diversion of at least a part of emanating water currents directed toward the surface of the underwater structure (22) , c h a r a c t e r i z e d i n that said cleaning roller (6, 8) and flow diverter (24, 26), via operational cooperation, are structured in a manner allowing them too independently provide said directional diversion so as to produce a net flow-generated reaction force (F) capable of driving the cleaning device in the direction of the surface of the underwater structure (22) , which will force the cleaning roller (6, 8) toward the underwater5 structure surface, whereby said cooperation and resulting reaction force (F) form an independent driving means for the cleaning device (2) .
2. The cleaning device (2) according to claim 1, c h a r a c t e r i z e d i n that said diverter surface0 (28, 30) is structured for directional diversion parallel to the surface of the underwater structure (22) .
3. The cleaning device (2) according to claim 1 or 2 , c h a r a c t e r i z e d i n that said diverter surface (28, 30) is structured for directional diversion away from the surface of the underwater structure (22) .
4. The cleaning device (2) according to claim 1, 2 or 3 , c h a r a c t e r i z e d i n that said flow diverter (24, 26) is comprised of a diverter plate.
5. The cleaning device (2) according to claim 1, 2 or 3 , c h a r a c t e r i z e d i n that said flow diverter (24, 26) is comprised of a diverter housing which includes said diverter surface (28, 30) .
6. The cleaning device (2) according to claim 5, c h a r a c t e r i z e d i n that the diverter housing also includes a surface portion disposed adjacent to a circumference portion of the cleaning roller (6, 8), the circumference portion of which will have a rotational direction toward the surface of the underwater structure (22) during operation, the constellation of which will restrain water current between said surface portion and circumference portion.
7. The cleaning device (2) according to any one of claims 1-
6, c h a r a c t e r i z e d i n that said flow diverter (24, 26) is structured to be movable relative to said cleaning roller (6, 8) .
8. The cleaning device (2) according to any one of claims 1-
7, c h a r a c t e r i z e d i n that the cleaning device (2) , on a side which will face toward the surface of the underwater structure (22) during operation, is provided with at least one spacer (32) for allowing, during operation, a distance to be maintained between the surface of the underwater structure (22) and the rotational axis of the cleaning roller (6, 8) .
9. The cleaning device (2) according to claim 8, c h a r a c t e r i z e d i n that said spacer (32) is structured to be movable relative to said cleaning roller (6, 8) .
10. The cleaning device (2) according to any one of claims 1- 9, c h a r a c t e r i z e d i n that said rotary device (16, 18) is chosen from a group comprising:
- hydraulically operated rotary devices;
- pneumatically operated rotary devices;
- electrically operated rotary devices; and - mechanically operated rotary devices.
11. The cleaning device (2) according to any one of claims 1- 10, c h a r a c t e r i z e d i n that said cleaning elements (12, 14) are comprised of outwardly extending elements chosen from a group comprising: - brushes;
- blades;
- knobs ; and
- buttons .
12. The cleaning device (2) according to any one of claims 1- 11, c h a r a c t e r i z e d i n that the cleaning device (2) also is provided with a collecting device for waste released from the surface of the underwater structure (22) .
13. The cleaning device (2) according to any one of claims 1- 12, c h a r a c t e r i z e d i n that the cleaning device (2) is provided with only one cleaning roller (6, 8) .
14. The cleaning device (2) according to any one of claims 1- 12, c h a r a c t e r i z e d i n that the cleaning device (2) is provided with at least one pair of cooperating cleaning rollers (6, 8) which are disposed at a distance from each other, and which are structured for production of said directional diversion and net reaction force (F) through rotation of the cleaning rollers (6, 8) in opposite rotational directions.
15. The cleaning device (2) according to claim 14, c h a r a c t e r i z e d i n that a pair of cooperating cleaning rollers (6, 8), when structured for production of said directional diversion and net reaction force (F) through rotation in a direction toward each other at the surface of the underwater structure (22) , is provided each with a rotary device (16, 18) and each with a flow diverter (24, 26) .
16. The cleaning device (2) according to claim 14, c h a r a c t e r i z e d i n that a pair of cooperating cleaning rollers (6, 8) , when structured for production of said directional diversion and net reaction force (F) through rotation in a direction away from each other at the surface of the underwater structure (22) , is provided each with a rotary device (16, 18) and each with a flow diverter (24, 26) .
17. The cleaning device (2) according to claim 14, c h a r a c t e r i z e d i n that a pair of cooperating cleaning rollers (6, 8) , when structured for production of said directional diversion and net reaction force (F)
5 through rotation in a direction away from each other at the surface of the underwater structure (22) , is provided each with a rotary device (16, 18) and a joint flow diverter .
18. A method of cleaning a surface of an underwater structureo (22), the method comprising the following steps:
(A) using a cleaning device (2) comprising:
- a support structure (4) ;
- at least one cleaning roller (6, 8) which is rotatable about its longitudinal axis, which is provideds with external cleaning elements (12, 14), and which is fastened to the support structure (4) ;
- at least one rotary device (16, 18) connected to said cleaning roller (6, 8) for rotation thereof; and
- at least one flow diverter (24, 26) which 0 includes a diverter surface (28, 30) structured for directional diversion of at least a part of emanating water currents directed toward the surface of the underwater structure (22) ;
(B) lowering the cleaning device (2) into water (20) in5 vicinity of said underwater structure surface;
(C) by means of a driving means, forcing said cleaning roller (6, 8) toward the surface of the underwater structure (22) ;
(D) by means of said rotary device (16, 18) , rotatingo said cleaning roller (6, 8) about said longitudinal axis for rotational cleaning of the surface of the underwater structure (22), c h a r a c t e r i z e d i n that the method also comprises:
- in step (A), structuring said cleaning roller (6, 8) and flow diverter (24, 26) in a manner allowing them to independently provide, via operational cooperation, said directional diversion so as to produce a net flow- generated reaction force (P) capable of driving the cleaning device in the direction of the surface of the underwater structure (22) ; and
- in step (D) , rotating the cleaning roller (6, 8) in a rotational direction which directs emanating and underwater- structure-directed water currents toward the flow diverter (24, 26) and thus produces said net flow- generated reaction force (F) , which will force the cleaning roller (6, 8) toward the underwater structure surface, whereby said cooperation and resulting reaction force (F) form an independent driving means for the cleaning device (2) .
19. The method according to claim 18, c h a r a c t e r i z e d i n that the method also comprises :
- in step (A) , using a cleaning device (2) including at least one pair of cooperating cleaning rollers (6, 8) which are disposed at a distance from each other, and which are structured for production of said directional diversion through rotation of the cleaning rollers (6, 8) in opposite rotational directions; and
- in step (D) , rotating the cleaning rollers (6, 8) in opposite rotational directions for production of said net reaction force (F) , which forces said cleaning rollers (6, 8) toward the surface of the underwater structure (22) .
20. The method according to claim 19, c h a r a c t e r i z e d i n that the method also comprises :
- in step (A) , using a cleaning device (2) wherein said pair of cleaning rollers (6, 8) is provided each with a rotary device (16, 18); and
- in step (D) , rotating the one cleaning roller faster than the other cleaning roller, whereby the cleaning device (2) is driven along the surface of the underwater structure (22) .
21. The method according to claim 19 or 20, c h a r a c t e r i z e d i n that the method also comprises a step (E) of reversing the rotational directions of the cleaning rollers (6, 8) , whereby the cleaning rollers (6, 8) are forced outwards and away from the surface of the underwater structure (22) . |
A CLEANING DEVICE FOR AN UNDERWATER STRUCTURE AND ALSO A METHOD OF USING SAME
Area of the invention
The present invention concerns a cleaning device for a surface of an underwater structure, for example a net structure in a breeding farm, an underwater hull, a marine structure, an offshore installation, a platform leg, an underwater pillar or similar. The invention also concerns a method of cleaning the surface of the underwater structure .
Background of the invention
The background of the invention is from the breeding of marine organisms, such as fish and shells, in breeding farms placed in the sea. However, such breeding farms may just as well be placed in a lake or in a river.
Common to most such breeding farms is the use of flow-through net structures for storage and cultivation of the particular marine organisms. In fish farming, enclosures in the form of large net bags, or aquaculture net cages, extending down into
the sea and enclosing the farmed fish are used. In connection with modern shellfish breeding farms, long floating nets which are stretched out and extend down into the sea are oftentimes used. The floating net may be comprised of a coarse-meshed net onto which farmed shellfish, for example blue mussels, are attached and are cultivated.
Oftentimes, such breeding farms will be located in the sea for a long time, possibly permanent, and will thus be subjected to various marine fouling. Generally, such marine fouling is undesirable inasmuch as the fouling gradually plugs up the net structure and increases the weight of the breeding farm. The fouling also restricts throughput of water, which contains oxygen and nutrients to the farmed organisms. For these reasons, such fouling must be removed regularly from the net structure. Removal of such fouling from the surfaces of other types of underwater structures may also be desirable or necessary, for example from hulls, legs, pillars, offshore installations, marine structures and the like.
It is stressed, however, that even though the background of the invention is in the aquaculture industry, there are obvious applications for the present cleaning device and method in other branches of industry.
Prior art and disadvantages thereof
Depending on what type of underwater structure is to be cleaned, there are different types of devices and methods for such cleaning.
For smaller underwater structures, it may prove most appropriate to remove the structure from the water and clean it onshore . Smaller net structures may be taken onshore and cleaned manually. This method of cleaning the structure may be inefficient given that it is heavy, labour-intensive and/or expensive.
For larger underwater structures , the cleaning is most appropriately carried out under water. In this connection it is known to use divers to carry out high pressure jetting of the underwater structure, which may prove cumbersome, labour- intensive, expensive and/or dangerous. Larger underwater structures may also be placed in a dry dock for further cleaning. Alternatively, a brush device, disc device or jetting device lowered into the water, but which is operated and controlled by personnel located above water, may be used. All of these cleaning methods are relatively comprehensive and comparatively inefficient.
Concerning cleaning of net structures for use in the aquaculture industry, the closest prior art appears to be represented by the following patent publications:
- JP 4234927; and
- CN 2882246 Y.
Both of these publications describe a remotely operated cleaning device for a net structure placed under water. The cleaning device comprises a hull having a front end provided with rotatable brushes which, when under water, will face toward the net structure for cleaning thereof. The hull is also provided with at least one separate propulsion device of propeller-type for allowing the cleaning device to be driven
toward the net structure, possibly also along the net structure, during the cleaning operation. Both publications describe a relatively comprehensive and complicated cleaning device.
Also, the following patent publications are mentioned as background prior art :
- NO 303312, which corresponds to WO 98/58535;
- JP 9009818;
- NO 322173; - NO 310902; and
- NO 313746.
Both NO 303312 (WO 98/58535) and JP 9009818 describe a cleaning device for a net wall, in which the very cleaning is carried out by means of brushes mounted on the inside of a submersible hull. The hull consists of two separate hull parts which, when in position of use, are positioned opposite each other on each side of the net wall. The hull parts are attracted to each other by means of magnetic forces exerted by magnets disposed in the hull. Moreover, each hull part is provided with rollers/wheels for allowing the hull to be moved along the net wall. In NO 303312, each hull part is provided with brushes facing toward the net wall for cleaning therof, whereas in JP 9009818 only the one hull part is provided with brushes directed toward the net wall. However, both publications assume use of magnetic forces in order to force the hull parts against each other and against the net wall during cleaning thereof. Both publications describe a relatively comprehensive and complicated cleaning device which, due to use of magnetic forces to keep separated hull parts connected, are relatively unreliable and unpractical.
NO 322173, NO 310902 and NO 313746 also describe submersible cleaning units for net bags, among other things. However, such a cleaning unit comprises one or several rotatable wash discs proved with wash nozzles for jetting and cleaning of a net bag or other type of underwater structure . The cleaning unit is lowered into water and is guided toward the underwater structure. In NO 322173, the cleaning unit is guided toward and along a net by means of propulsion elements, for example propellers, mounted thereon. In NO 310902, the cleaning unit is formed with external, bevelled foil surfaces which, when the unit is moved in the water, form a foil effect forcing the unit toward a net. In NO 313746, it is indicated that the force of gravity is used to keep the cleaning unit stable relative to an underwater structure during cleaning thereof.
NO 310768 is also mentioned in this connection, which describes a suspension arrangement for automatic guiding of a cleaning device for an underwater structure, such as marine structures, net cage, ship hulls, platforms, etc. Another type of suspension arrangement for such a cleaning device is also shown in said JP 9009818.
The objects of the invention
The primary object of the invention is to provide a simple and efficient technical solution for cleaning a surface of an underwater structure .
A more specific object of the invention is to provide a technical solution for simple and efficient removal of fouling on a net structure in a breeding farm.
How to achieve the objects
Said object are achieved by virtue of features disclosed in the following description, which the subsequent claims are based upon.
According to a first aspect of the invention there is provided a cleaning device for a surface of an underwater structure, the cleaning device comprising:
- a support structure;
- at least one cleaning roller which is rotatable about its longitudinal axis, which is provided with external cleaning elements, and which is fastened to the support structure; and
- at least one rotary device connected to said cleaning roller for rotation thereof. Such rotation under water will generate water currents emanating from said cleaning roller. The distinctive characteristic of the cleaning device is that it is provided with at least one flow diverter which includes a diverter surface structured for directional diversion of at least a part of emanating water currents- directed toward the surface of the underwater structure.
Said flow diverter is structured in a manner allowing it to divert emanating water currents coming from at least a longitudinal portion of said cleaning roller.
Yet further, and as mentioned above, the underwater structure may, for example, be comprised of a net structure, an underwater hull, a marine structure, an offshore installation, a platform leg, an underwater pillar or similar.
For use under water, the cleaning device may be lowered from a suitable suspension arrangement and be placed in vicinity of the underwater structure. Such a suspension arrangement does not form a part of the present invention and, therefore,
will not be discussed in detail herein. However, it is obvious that a suspension arrangement of a type described in the above-mentioned NO 310768 and JP 9009818 may be used in this connection.
Upon having placed the cleaning device in its position of use under water and upon rotating said cleaning roller in the right direction about its longitudinal axis, said directional diversion will produce a net flow-generated reaction force toward the surface of the underwater structure. Thereby, the cleaning device and the cleaning roller are also forced toward the surface of the underwater structure . The cleaning roller and the resulting reaction force thus form a driving means for the cleaning device. This principle of propulsion distinguishes the present cleaning device for all of the cleaning devices according to the above-mentioned prior art.
It is to be mentioned in this connection that emanating water currents will emanate, to a large extent, tangentially from the circumference of the cleaning roller, and they will have a discharge speed that depends on the rotational speed of the cleaning roller. Without any form of directional diversion, these water currents will emanate in all direction from the circumference of the cleaning roller. Reaction forces caused by these emanating water currents will thus neutralize each other, whereby no net flow-generated reaction force is produced. On the other hand, and in order to produce a net reaction force that will force the cleaning device toward the surface of the underwater structure during cleaning, at least a part of the underwater-structure-directed water currents must be re-directed in another direction. This is because underwater-structure-directed water currents will produce reaction forces directed away from the surface of the underwater structure, which is an undesirable effect during
the cleaning operation. Emanating water currents directed away from the surface of the underwater structure, contribute on the other hand to produce reaction forces directed toward the surface of the underwater structure, which is a desirable effect during the cleaning operation. For this reason, water currents directed away from the underwater structure should be allowed to flow as unrestricted and freely as possible.
By attenuating or removing reaction forces directed away from the surface of the underwater structure, a net flow-generated reaction force toward the surface of the underwater structure will be produced. This is achieved by means of said flow diverter and its diverter surface .
As such, the diverter surface of the flow diverter may be structured for directional diversion parallel to and/or away from the surface of the underwater structure .
In one embodiment, said flow diverter may be comprised of a diverter plate.
In another embodiment, said flow diverter may be comprised of a diverter housing which includes said diverter surface. The diverter housing may have any form suitable for allowing said underwater-structure-directed water currents to be diverted. Insofar as such a diverter housing has an extent both in terms of area and volume, the housing may also have a form which is suitable for appropriate directional control of other water currents present around the cleaning device during^ operation in water. Such a diverter housing may also function as a part of said support structure of the cleaning device.
The diverter housing may also include a surface portion disposed adjacent to a circumference portion of the cleaning roller, the circumference portion of which will have a
rotational direction toward the surface of the underwater structure during operation. Such a constellation will restrain water current between said surface portion and circumference portion.
Said flow diverter may also be structured to be movable relative to said cleaning roller. This may be advantageous during replacement of the cleaning roller, possibly to be able to use another type of cleaning roller having, for example, a different outer dimension, different shape and/or a different type of cleaning element on the outside of the cleaning roller.
Moreover, on a side which will face toward the surface of the underwater structure during operation, the cleaning device may be provided with at least one spacer for allowing, during operation, a distance to be maintained between the surface of the underwater structure and the rotational axis of the cleaning roller. Such a spacer may be structured in flow- through or bypass-flow manner. Upon maintaining a certain distance between the surface of the underwater structure and the rotational axis of the cleaning roller, the contact of the cleaning roller with said surface may be adapted to the particular type of cleaning element on the outside of the cleaning roller, and also adapted to the particular type of surface to be cleaned. For a net structure, this surface may be comprised of a flow-through wicker work of thread, whereas this surface may be tight and impervious for an underwater hull, pillar or similar.
Yet further, the spacer may consist of a grate structure made from, for example, bails, pipes, rods, wire, etc. of a suitable material, for example metals or plastics. Thus, the
spacer will also function as a barrier between the surface of the underwater structure and the cleaning roller. If the underwater structure is comprised of a flexible net structure or similar, such a barrier may be useful for avoiding that the cleaning roller (s) pull(s) the flexible net structure into the cleaning device and thus causes shutdown or possible damages to the net structure and/or the cleaning device . The spacer may also be comprised of, or include, spacer wheels, spacer rollers or similar movement elements. The latter may be advantageous during cleaning of an impervious surface .
Said spacer may also be structured to be movable relative to said cleaning roller. This may be advantageous for allowing the distance to be adjusted between the surface of the underwater structure and the cleaning roller, and thus to be able to adjust the cleaning roller's depth and/or compressive force toward said surface.
Said rotary device for the at least one cleaning roller may be chosen from a group comprising:
- hydraulically operated rotary devices; - pneumatically operated rotary devices;
- electrically operated rotary devices; and
- mechanically operated rotary devices.
Such rotary devices may receive a corresponding motive power from remote or local power sources and via suitable transmission connections. Preferably, the operation and control of the cleaning device is carried out via remote control from surface, and via suitable cabled or wireless connections. Such operation and control may also be carried out locally. During remote operation of the cleaning device,
also remotely controlled surveillance cameras and light sources may be used to the extent necessary or desirable.
Yet further, said cleaning elements may be comprised of outwardly extending elements chosen from a group comprising: - brushes;
- blades;
- knobs ; and
- buttons .
In this connection, cleaning elements are used which, when placed on the cleaning roller, are structured with a suitable length, distribution and density with respect to the particular cleaning operation.
The cleaning device may also be provided with a collecting device for waste released from the surface of the underwater structure. Such a collecting device may, for example, be comprised of a collecting net or suction device for such waste .
In one embodiment, the cleaning device may be provided with only one cleaning roller.
In another embodiment, the cleaning device may be provided with at least one pair of cooperating cleaning rollers which are disposed at a distance from each other, and which are structured for production of said directional diversion and net reaction force through rotation of the cleaning rollers in opposite rotational directions.
Rotation in opposite rotational directions may be carried out either by rotating the cleaning rollers toward each other or away from each other at the surface of the underwater structure. This becomes important for the placement of the flow diverters in the cleaning device.
Upon rotation toward each other at the surface of the underwater structure, water currents will be generated in a flow region located between and possibly immediately outside the cleaning rollers, the water currents of which are directed away from the surface of the underwater structure. Water currents directed toward the surface of the underwater structure will then be generated on the opposite and external sides of the rollers, the water currents of which must, according to the invention, be re-directed by means of flow diverters .
Accordingly, a pair of cooperating cleaning rollers, when structured for production of said directional diversion and net reaction force through rotation in a direction toward each other at the surface of the underwater structure, may be provided each with a rotary device and each with a flow diverter. Each flow diverter will then be structured in a manner allowing water currents to be re-directed toward the surface of the underwater structure at said external sides of • the rollers. This implies that the flow diverters are placed within or in immediate vicinity of said external sides of the rollers . The subsequent exemplary embodiment shows two cleaning rollers cooperating in this manner.
Upon rotation away from each other at the surface of the underwater structure, water currents will be generated in the flow region located between and possibly immediately outside
the cleaning rollers, the water currents of which are directed toward the surface of the underwater structure, and the water currents of which must, according to the invention, be re-directed by means of at least one flow diverter. Water currents directed away from the surface of the underwater structure will then be generated on the opposite and external sides of the rollers.
Accordingly, a pair of cooperating cleaning rollers, when structured for production of said directional diversion and net reaction force through rotation in a direction away from each other at the surface of the underwater structure, may be provided each with a rotary device and each with a flow diverter, alternatively provided each with a rotary device and a joint flow diverter. Each flow diverter or the joint flow diverter will then be structured in a manner allowing water currents to be re-directed toward the surface of the underwater structure at said flow region between and possibly immediately outside the cleaning rollers. This implies that each flow diverter, alternatively the joint flow diverter, is placed within or in immediate vicinity of said flow region.
According to a second aspect of the invention there is provided a method of cleaning a surface of an underwater structure, the method comprising the following steps:
(A) using a cleaning device comprising: - a support structure;
- at least one cleaning roller which is rotatable about its longitudinal axis, which is provided with external cleaning elements, and which is fastened to the support structure ; and - at least one rotary device connected to said cleaning roller for rotation thereof;
(B) lowering the cleaning device into water in vicinity of
said surface of the underwater structure;
(C) by means of a driving means, forcing said cleaning roller toward the surface of the underwater structure;
(D) by means of said rotary device, rotating said cleaning roller about said longitudinal axis for rotational cleaning of the surface of the underwater structure .
The distinctive characteristic of the method is that it also comprises :
- in step (A) , using a cleaning device which also is provided with at least one flow diverter including a diverter surface structured for directional diversion of at least a part of emanating water currents directed toward the surface of the underwater structure; and
- in step (D) , rotating said cleaning roller in a rotational direction which directs emanating and underwater-structure- directed water currents toward said flow diverter so as to produce a net flow-generated reaction force which forms said driving means, and which forces said cleaning roller toward the surface of the underwater structure .
According to one embodiment, the method may also comprise the following:
- in step (A) , using a cleaning device including at least one pair of cooperating cleaning rollers which are disposed at a distance from each other, and which are structured for production of said directional diversion through rotation of the cleaning rollers in opposite rotational directions; and
- in step (D) , rotating the cleaning rollers in opposite rotational directions for production of said net reaction force, which forces said cleaning roller toward the surface of the underwater structure .
The method may also comprise:
- in step (A) , using a cleaning device wherein said pair of
cleaning rollers are provided each with a rotary device; and - in step (D) , rotating the one cleaning roller faster than the other cleaning roller, whereby the cleaning device is driven along the surface of the underwater structure .
The latter is related to the fact that the cleaning rollers, upon being rotated in opposite rotational directions when in position of use, also produce oppositely directed reaction forces parallel to the surface of the underwater structure. Upon equal rotational speeds, these parallel-extending reaction forces will neutralize each other. Upon unequal rotational speeds, the cleaning roller having the largest rotational speed will produce a larger reaction force than the reaction force from the cleaning roller having the smallest rotational speed. Thereby, a net reaction force which is parallel to the surface of the underwater structure, and which drives the cleaning device along the surface, is produced. The movement of the cleaning device along the surface of the underwater structure may thus be controlled through appropriate control of the rotational speed of the cleaning rollers.
Yet further, the method may also comprise a step (E) of reversing the rotational direction of the cleaning rollers, whereby the cleaning rollers are forced outwards and away from the surface of the underwater structure. This step may be useful, among other things, for cleaning waste from the cleaning rollers and their cleaning elements.
A non- limiting exemplary embodiment of a cleaning device according to the invention will now be shown.
Short description of the figures of the exemplary embodiment
Figure 1 shows a cleaning device according to the invention as viewed in a bird's-eye perspective and comprising two parallel and cooperating cleaning rollers;
Figure 2 shows the cleaning device according to figure 1 as viewed in a worm's eye perspective;
Figure 3 shows a front elevation of the cleaning device according to figures 1 and 2, where figure 3 also shows a horizontal section line B-B through the cleaning device;
Figure 4 shows a side elevation of the cleaning device according to figure 3, where figure 4 also shows the cleaning device placed against a net structure suspended in water;
Figure 5 shows a base view of the cleaning device as viewed along said section line B-B in figure 3, where figure 5 also shows the cleaning device placed against said net structure;
Figure 6 shows the cleaning device according to figure 5 when in position of use and during cleaning of said net structure, where figure 6 also shows a net flow-generated reaction force F forcing the cleaning device against the net structure; and
Figure 7 shows the cleaning device according to figure 6, but where the device also includes a secondary flow diverter placed between the cleaning rollers.
The figures are somewhat simplified and only shows essential elements of the cleaning device. The shapes, relative
dimensions and mutual positions of the elements may also be somewhat distorted. In the following, equal, equivalent or corresponding details in the figures will generally be assigned the same reference numeral.
Description of the exemplary embodiment
Figures 1 and 2 show perspective views of a cleaning device 2 according to the invention, whereas figures 3-5 show the cleaning device 2 as viewed from different angles.
The cleaning device 2 comprises a flow-through and supporting frame structure 4, which includes a top plate 4a and a bottom plate 4b connected at a distance from each other by means of several spacer pipes 4c.
Two parallel and cooperating cleaning rollers 6 and 8, each of which is rotatable about its longitudinal axis, are disposed between the top plate 4a and the bottom plate 4b. Each cleaning roller 6, 8 is rotatably supported in the top plate 4a and the bottom plate 4b by means of suitable supports 10, for example ball-bearings. In addition, each cleaning roller 6, 8 is provided with external cleaning elements in the form of brushes 12 and 14. Each cleaning roller 6, 8, at the lower end thereof, is also connected to a hydraulic motor 16, 18 for rotation of the cleaning roller 6, 8.
In position of use under water 20, when the cleaning device 2 is disposed in vicinity of a flexible net structure 22 to be cleaned, the hydraulic motors 16, 18 will be connected to a remote or local power unit for supply of hydraulic motive power via suitable hydraulic lines. The cleaning device 2 is
operated and remotely controlled from surface, and via cabled or wireless connections. If necessary or desirable, also remotely controlled surveillance cameras and light sources may be used. However, this is not shown in the figures. Said net structure 22 may, for example, be comprised of a coarse- meshed net for breeding of blue mussels, or a net bag for a aquaculture net cage .
The distinctive characteristic of the cleaning device 2 is that each cleaning roller 6, 8 is associated with a flow diverter, which in this exemplary embodiment is comprised of a diverter plate 24, 26. Each diverter plate 24, 26 includes a diverter surface 28, 30 structured for directional diversion of at least a part of those water currents which are directed toward said net structure 22 upon emanating from the associated cleaning roller 6, 8 during rotation thereof. In figures 6 and 7, the flow directions of emanating water currents are indicated with black, downstream-directed arrows. In these figures, also the cleaning rollers 6, 8 have black arrows applied thereto indicating their rotational directions during the cleaning operation.
The cleaning device 2 is also provided with a spacer in the form of a grate structure 32 for allowing, during operation, a distance to be maintained between the net structure 22 and the rotational axes of the cleaning rollers 6, 8. In this exemplary embodiment, the grate structure 32 includes three pipe bails 32a connected by means of a number of tie bars 32b. The pipe bails 32a extend between the top plate 4a and the bottom plate 4b of the frame structure 4 and are fastened thereto via respective upper end portions 32a' and lower end portions 32a' ' . The grate structure 32 functions like a barrier between the net structure 22 and the cleaning rollers
6, 8. All figures except figure 4 show the external cleaning brushes 12, 14 of the cleaning rollers 6, 8 carried partially through the grate structure 32. Thereby, the cleaning brushes 12, 14 are also carried partially through the mesh openings in the net structure 22 when bearing against the net structure 22. In this manner, both sides of the net structure 22 as well as the thread surfaces defining the mesh openings in the net structure 22 are cleaned. By so doing, an extremely good cleaning result is achieved. The grate structure 32 also prevents the flexible net structure from being pulled into the cleaning device 2 during rotation of the cleaning rollers 6, 8.
In this exemplary embodiment, the grate structure 32 is structured to be movable relative to the cleaning rollers 6, 8. This is possible by virtue of the end portions 32a', 32a'' of the pipe bails 32a being releasably fastened to the top plate 4a and the bottom plate 4b, respectively. This is shown in best mode in figures 1 and 2. By means of suitable fastening means, which in this example are comprised of threaded bolts and associated nuts, said end portions 32a' , 32a' ' are releasably fastened to the top plate 4a and the bottom plate 4b via respective, longitudinally extending holes 34a and 34b therethrough. Figure 5 shows the lower end portions 32a' ' releasably fastened to the bottom plate 4b, the upper end portions 32a' being fastened in a corresponding manner to the top plate 4a. The holes 34a, 34b have a longitudinal extent which is perpendicular to the net structure 22 when the cleaning device 2 is placed against the net structure 22. By unfastening the fastening means, the grate structure 32 may be moved relative to the net structure 22, whereby the distance between the net structure 22 and the cleaning rollers 6, 8 may be adjusted.
Figures 6 and 7 show the cleaning device 2 in operation under water 20 and placed against the net structure 22 during cleaning thereof. In order to illustrate the flow pattern better, the grate structure 32, the holes 34a, 34b and various spacer pipes 4c have been removed from figures 6 and 7.
The embodiments according to figures 6 and 7 show a pair of cooperating cleaning rollers 6, 8 structured for production of said directional diversion and net reaction force F. In this case, this effect is achieved through rotation of the cleaning rollers 6, 8 in a direction toward each other at the surface of the net structure 22. As a result of this rotational pattern, water currents will be generated which are directed away from the net structure 22 in a flow region 36 located between and immediately outside the cleaning rollers 6, 8. Simultaneously, on the opposite and external sides of the cleaning rollers 6, 8, water currents will be generated which are directed toward the net structure 22 and which, according to the invention, are re-directed by means of said diverter plates 24, 26. The resulting flow pattern generates a net reaction force F which is directed toward the net structure 22, and which may force the cleaning device 2 with significant force toward the net structure 22. Said flow pattern is indicated with black, downstream-directed arrows, whereas the reaction force F is indicated with a broad, white arrow in the figures.
Upon reversing the rotational directions of the cleaning rollers 6, 8, however, the cleaning rollers 6, 8 will be forced away from the net structure 22. This may be useful for cleaning waste from the cleaning brushes 12, 14 on the cleaning rollers 6, 8.
In figure 7, the cleaning device 2 is also provided with a secondary flow diverter in the form of a triangular structure 38 placed between the cleaning rollers 6, 8 and within said flow region 36. The triangular structure 38 provide further directional assistance for outwardly directed water currents, but it may also serve to counteract interfering backflow of water to the flow region 36 and toward the cleaning rollers 6, 8.
A further advantageous feature of the present invention is that the cleaning device 2 may be driven along the net structure 22 by rotating the one cleaning roller 6 faster than the other cleaning roller 8, or vice versa. This is carried out through appropriate control of their hydraulic motors 16, 18. Upon unequal rotational speeds of the cleaning rollers 6, 8, a net reaction force which is parallel to the net structure 22 is produced, the net reaction force of which thus drives the cleaning device 2 along the net structure 22. This may be exploited appropriately for movement along the net structure 22 during cleaning thereof.