Cleaning module, cleaning devices and cleaning processes for underwater cleaning of ship hulls

Abstract

Cleaning module for underwater cleaning of a ship's hull (9) from growth (11) by marine organisms, comprising: - an ultrasonic plate oscillator (1), - a frame (4) formed in one plane and closed all around, - at least three magnetic positioning and fastening actuators (3) attached to the frame (4), and - a control and regulation unit, characterized in that the cleaning module further comprises: - several hexapod actuators (2) connecting the ultrasonic plate oscillator (1) and the frame (4) to form a hexapod, - a suction device (5) surrounding the ultrasonic plate oscillator (1) for sucking off the growth (11) detached from the ship's hull (9), and - a sensor unit designed to detect the position on the ship's hull (9) and to detect the distance of the ultrasonic plate oscillator (1) from the ship's hull (9), wherein the at least three magnetic positioning and fastening actuators (3) attached to the frame (4) are designed for positioning and magnetically fixing the hexapod to the ship's hull (9) and for adjusting the distance of the hexapod to the ship's hull (9), and wherein the control and regulation unit is arranged to control the position and orientation of the ultrasonic plate oscillator (1) relative to the ship's hull (9) and to regulate the distance of the ultrasonic plate oscillator (1) from the ship's hull (9).

Description

[0001] The invention relates to a cleaning module, cleaning devices equipped with the cleaning module and a cleaning method for underwater cleaning of ship hulls covered with marine organisms, which are particularly suitable for proactive cleaning of ship hulls covered with biofilms.

[0002] Due to its high transport volume, commercial shipping is one of the most environmentally friendly and energy-efficient modes of transport. Irrespective of this, shipping is also constantly striving to save fuel and reduce emissions. A serious problem that contributes to increasing emissions is the growth of marine fauna and flora on ships. This type of growth is caused, among other things, by extended layovers in marine areas with intensive growth or reduced speed ("slow steaming") of 8 to 12 knots due to low capacity utilization. But even minimal growth, known as biofilm, increases fuel consumption and thus emissions. In order to save fuel and keep operating costs low, many shipowners have their hulls cleaned even when the growth of biofilm is minimal.

[0003] Conventionally, cleaning is carried out by divers, mechanical systems, such as those equipped with brushes, or in dry docks. However, brushing or high-pressure water jets often damage or remove the antifouling coating applied to the ship's hull to inhibit growth. However, cleaning over the antifouling coatings is prohibited in many ports or at least requires a permit due to the risk of water contamination from the biocides contained in the established antifouling coatings.

[0004] Underwater cleaning of ships moored in harbors or at anchor is primarily performed by divers using special equipment with powered rotating brushes. Also known are robot-based cleaning devices based on remotely operated vehicles (ROVs), which can perform this cleaning semi-automatically while the ship is in port for loading or unloading. In addition to brush- or water-jet-based cleaning devices and methods, ultrasound-based cleaning processes for cleaning ship hulls have been proposed, as is evident, for example, from DE 24 50 593 A1.

[0005] US Patent No. 4,890,567 describes a robotic cleaning device that uses ultrasonic cavitation in combination with liquid sprays to remove biofouling and toxic coatings from ship hulls. Cleaning takes place within a closed housing that is held and moved on the ship's hull by a magnetic chassis. The device is specifically designed for use in dry docks.

[0006] EP 2 497 708 A1 discloses a device for determining the position of a movable cleaning or inspection unit on a surface, in particular on a ship's hull. The device combines an optical and a magnetic detection system to evaluate both surface and subsurface features for precise navigation and position detection.

[0007] JP 2014-43200 A describes an underwater cleaning device for cleaning ship bottoms and sides, which moves along the ship's surface. The device is equipped with rotating brushes and drive thrusters and uses special position sensors to precisely track its trajectory. Position determination is achieved using a mechanical roller system (distance measuring roller) in combination with sensors for detecting the roll rotation, the contact pressure, and the direction of rotation, thus allowing the direction and distance of movement to be determined.

[0008] The object of the invention is to provide a cleaning module, cleaning devices and a cleaning method for the gentle underwater cleaning of ship hulls, which make it possible to clean ship hulls with different main frame constructions without the use of divers, whereby the contamination of the seawater with biocide-containing antifouling layer detachments is to be avoided.

[0009] This object is achieved by a cleaning module for underwater cleaning of a ship's hull according to claim 1, the cleaning devices equipped with the cleaning module according to claims 5 and 6, and the cleaning method according to claim 7. Appropriate developments of the invention are listed in claims 2 to 4 and 8 to 10.

[0010] According to the invention, the cleaning module, which is intended to remove marine growth on the ship's hull, comprises an ultrasonic plate transducer, a circumferentially closed frame formed in a single plane, and several (usually six) hexapod actuators. The hexapod actuators connect the ultrasonic plate transducer and the frame to form a hexapod. The frame preferably has a hexagonal shape.

[0011] At least three (preferably four) magnetic positioning and fastening actuators are attached to the frame, which serve to position and magnetically fix the hexapod to the ship's hull and to adjust or adjust the distance of the hexapod to the ship's hull.

[0012] The hexapod actuators, as well as the positioning and mounting actuators, are linear adjustment units that are articulated at their end sections in a generally known manner. These are preferably fluid-dynamically optimized, high-strength lightweight components with hybrid axes (e.g., a combination of an electromechanical drive with a hydraulic axis or a toothed belt linear unit with a hydraulic drive).

[0013] When used as intended for cleaning a ship's hull, the cleaning module is first secured in the area of ​​one of several cleaning fields located on the hull using positioning and fastening actuators. Ultrasound is then emitted toward the overgrown hull using an ultrasonic plate transducer appropriately aligned to the hull. The ultrasonic waves and the cavitation effects they trigger in the water detach the growth from the hull. Once the growth in the cleaning field has been removed or the desired level of cleaning has been achieved, the cleaning module can be moved to another location on the hull to continue underwater cleaning in the cleaning field created there.By gradually relocating the cleaning module and the associated relocation of the respective cleaning field, the growth on the entire ship's hull can finally be removed.

[0014] The ultrasonic plate oscillator of the cleaning module according to the invention is housed or enclosed by a suction device for extracting the growth detached from the ship's hull. This means that the suction device is only open toward the ship's hull or has a suction opening extending upwards toward the ship's hull. The suction device is preferably designed to be contour-flexible, i.e., the peripheral edge of the suction opening can adapt to the contours of the ship's hull. The detached and vacuumed growth is conveyed, for example, via a hose system to a dinghy for filtration / dewatering and transport.

[0015] Furthermore, the cleaning module has a sensor unit designed to detect the position on the ship's hull and to detect the distance of the ultrasonic plate transducer from the ship's hull, and a control and regulation unit designed to control the position and orientation of the ultrasonic plate transducer relative to the ship's hull and to regulate the distance of the ultrasonic plate transducer from the ship's hull.

[0016] Preferably, the sensor unit is also configured to detect the contour of the ship's hull (in the form of a contour scan) or the distance of the ultrasonic plate transducer from the ship's hull in a spatially resolved manner in order to optimally adapt the alignment of the cleaning module and / or the ultrasonic plate transducer to the shape of the ship's hull (for example, to compensate for the frame angle).

[0017] The position and orientation of the ultrasonic plate transducer relative to the ship's hull are controlled by positioning and mounting actuators, which allow the distance and tilt of the entire hexapod (including the ultrasonic plate transducer) relative to the ship's hull to be adjusted. The hexapod actuators themselves can be used to change both the position within the cleaning field (preferably by vertically moving the ultrasonic plate transducer) and the tilt of the ultrasonic plate transducer. The distance of the ultrasonic plate transducer from the ship's hull can be adjusted through feedback from the data acquired by the sensor unit.

[0018] The control and regulation device is connected to the individual components, i.e. the ultrasonic plate transducer, the hexapod actuators, the positioning and fastening actuators, the sensor unit and, if necessary, other components, in a known manner.

[0019] The cleaning module is preferably powered directly by the ship; it can also have a power supply unit installed within the cleaning module. In addition to power from the ship, data can also be exchanged with the ship. The data can, for example, be forwarded to an operator who monitors the cleaning process in real time and intervenes if damage is detected.

[0020] According to the cleaning method according to the invention, which is carried out with the described cleaning module, the cleaning module is first fixed to the ship's hull by means of the positioning and fastening actuators in the area of ​​the cleaning field intended for cleaning. The ultrasonic plate transducer is then guided by the hexapod actuators over the area of ​​the cleaning field by controlling the hexapod actuators and the positioning and fastening actuators, preferably parallel to the ship's hull at a distance of 100 ± 20 mm. The growth is removed from the ship's hull by means of the ultrasound emitted by the ultrasonic plate transducer. The removed growth is finally vacuumed away by the suction device and conveyed to a dinghy, for example, via a suction hose connected to the suction device.

[0021] The frequency of the ultrasound emitted by the ultrasonic plate transducer is preferably in the range of 20 kHz to 25 kHz.

[0022] One of the advantages of the semi-automatic cleaning module and cleaning process according to the invention is the contactless and thus gentle cleaning of the ship's hull. The introduction of biocide-containing microparticles from antifouling coatings into the seawater is prevented by the suction device surrounding the ultrasonic plate transducer.

[0023] The design of the cleaning module as a contour-flexible manipulator, especially in conjunction with the rapidly variable positioning and orientation of the ultrasonic plate transducer achieved via the hexapod, enables the ultrasonic energy to be optimally coupled to the area of ​​the hull surface covered in vegetation, thus achieving the best possible cleaning results with minimal energy consumption. The cleaning module adapts flexibly to the hull surface, making it particularly suitable for cleaning uneven surfaces, bulges, and curves.

[0024] The high travel speed of the hexapod actuators also enables efficient travel across the cleaning field.

[0025] The magnetic fixation of the cleaning module by means of the positioning and fastening actuators during the cleaning process ensures that the optimal distance between the ultrasonic plate transducer and the hull surface is maintained.

[0026] The cleaning module is particularly suitable for proactive cleaning and grooming of ship hulls in the presence of biofilm growth. In addition to restoring a smooth, low-friction ship hull, which ensures optimal performance—i.e., low fuel consumption and reduced emissions—it also reduces the problem of the introduction of alien marine life.

[0027] Ultrasonic cleaning can also be performed during slow travel, minimizing layover times. The cleaning module can be secured from the deck using a mounting or emergency bracket.

[0028] According to one embodiment of the cleaning module, the sensor unit is designed to detect growth on the ship's hull, i.e., the sensor unit has suitable sensors that can be used to determine the growth or the growth intensity on the ship's hull. This allows, among other things, the degree of cleaning of the cleaned surfaces to be recorded.

[0029] The cleaning module's sensor unit can also include sensors for monitoring the environment, which can be used, for example, to perform a horizontal and / or vertical environmental scan. This allows for early detection and prevention of collisions with attachments to the ship's hull (especially when moving the cleaning module).

[0030] The cleaning module is preferably a subcomponent of a movable cleaning device or a cleaning system.

[0031] According to a first embodiment, such a cleaning device comprises, in addition to the cleaning module according to the invention, a linear gantry on which the cleaning module is suspended and height-adjustable. The linear gantry is attached to a linearly movable carriage that is magnetically attached to the ship's hull and serves for the horizontal linear movement of the cleaning module on the ship's hull, which is connected to the carriage via the linear gantry. The carriage typically moves above the growth surface on the ship's hull and rigidly guides the linear gantry. The carriage is designed, in particular, as a magnetic crawler, which enables dynamic, contour-independent attachment to the ship's hull.

[0032] To clean the ship's hull with this type of cleaning device, the cleaning module is moved along the ship's hull by the linearly movable, magnetically attached traversing unit, which moves the cleaning module horizontally to the respective cleaning area on the hull. During this horizontal movement of the traversing unit, the cleaning module is temporarily fixed to the hull by means of the positioning and fastening actuators. The vertical positioning or vertical movement of the cleaning module is carried out by means of the linear gantry.

[0033] The traversing unit and the linear gantry serve as motion actuators for positioning and repositioning the cleaning module on the ship's hull. Once a section of the hull has been cleaned, the cleaning module is moved to a new position and temporarily fixed in the cleaning field created there. The linear gantry (via the suspended arrangement of the cleaning module) compensates for the constant change in position or relative movement of the traversing unit with respect to the cleaning module temporarily fixed to the ship's hull, enabling a step-by-step relocation of the cleaning module.

[0034] When the cleaning module is moved, the magnetic positioning and fastening actuators compensate for external influences, such as wave movements or currents, so that the cleaning module cannot be pushed away from the ship's hull or swing against it.

[0035] The control and regulation unit is configured to control the horizontal movement via the travel unit and the vertical movement via the linear gantry. For cleaning the ship's hull, a path guidance with a cleaning pattern suitable for the respective ship can also be stored in the control and regulation unit.

[0036] Furthermore, an additional sensor unit can be attached to the travel unit or the linear gantry. This unit can be used, among other things, to perform horizontal environmental scans for collision warning, determine the horizontal position of the cleaning module relative to the linear gantry, and / or detect the varying holding forces of the cleaning module suspended from the linear gantry due to environmental influences. The sensors for determining the vertical position of the cleaning module relative to the linear gantry can also be part of the cleaning module's sensor unit.

[0037] According to a second, alternative embodiment of the cleaning device, the cleaning module according to the invention is integrated into a remotely operated underwater vehicle (ROUV), which docks onto the ship's hull and cleans the hull using the cleaning module according to a predetermined cleaning plan. During cleaning of the ship's hull, the underwater vehicle moves to the respective cleaning area to be treated, and the cleaning module is fixed to the ship's hull in the area of ​​this cleaning area. The cleaning device is repositioned after completion of cleaning of the respective cleaning area until the entire ship's hull is finally cleaned. The remotely operated underwater vehicle can be equipped with or without a magnetic crawler.

[0038] The cleaning module or cleaning devices can also be supplemented with virtual reality components to facilitate operation and for educational and training purposes.

[0039] For extended use of the cleaning module, the ultrasonic plate transducer can be replaced with a sensor based on alternating current induced field measurement (e.g., an ACFM probe) after cleaning. This makes it possible to inspect the ship's hull for structural defects after cleaning (e.g., in the area of ​​weld seams). Hyperspectral cameras or high-resolution sonars can also be used. This allows the cleaning of ship hulls to be combined with structural health monitoring (SHM) to detect structural defects at an early stage and initiate maintenance work.

[0040] The invention is explained in more detail below using an exemplary embodiment and with reference to the schematic drawings, in which identical or similar features are provided with the same reference numerals. In the drawings: Fig. 1: a variant of the cleaning device with the cleaning module in side view, and Fig. 2: this design variant of the cleaning device with the cleaning module in top view.

[0041] The cleaning module of the Fig. The cleaning device shown in Figure 1 is fixed to the side of the ship's hull 9 by means of the positioning and fastening actuators 3, whereby the square, an area of ​​1 m 2 having ultrasonic plate transducer 1 is located below the waterline 10.

[0042] The hexapod of the cleaning module consists of the ultrasonic plate transducer 1, the frame 4, and the hexapod actuators 2 connecting the ultrasonic plate transducer 1 to the frame 4. This hexapod enables—as indicated by the arrows—the vertical displacement of the ultrasonic plate transducer 1, the tilting of the ultrasonic plate transducer 1, and the change of the distance of the ultrasonic plate transducer 1 from the surface of the ship's hull 9.

[0043] By means of the positioning and fastening actuators 3, the orientation and distance of the hexapod in relation to the ship's hull 9 can also be changed (see arrows in the area of ​​the positioning and fastening actuators 3).

[0044] The ultrasonic plate transducer 1 is enclosed by the suction device 5, by means of which the growth 11 detached from the ship's hull 9 is sucked off and guided into a dinghy (not shown) by means of the suction hose 6.

[0045] Above the waterline 10, the magnetically adhering travel unit 8 (magnetic crawler) is located on the ship's hull 9. The line portal 7 is attached to the travel unit 8, to which the cleaning module is suspended and adjustable in height.

[0046] The side view of the ship's hull 9 in the Fig. The cleaning device shown in Figure 2 corresponds to the cleaning device of Fig. 1.

[0047] The Fig. 2 illustrates the position of the cleaning field 12 in which the ship's hull 9 is currently being cleaned by means of the ultrasonic plate transducer 1. After completion of the cleaning, the cleaning module can be moved by means of the traversing unit 8 and / or by means of the linear gantry 7 (according to the arrows) in order to position the cleaning module in a part of the ship's hull 9 that has not yet been cleaned (i.e., covered with growth 11).

[0048] The hexagonal frame 4 is connected to the ultrasonic plate transducer 1 via six hexapod actuators 2. The hexapod is supported on the ship's hull 9 via the four positioning and mounting actuators 3. List of reference symbols 1 ultrasonic plate transducer 2 hexapod actuators 3 Positioning and fixing actuator 4 frames 5 Suction device 6 Suction hose 7 Line portal 8 Traversing unit 9 Hull 10 Waterline 11 Vegetation 12 cleaning field

Claims

[1] Cleaning module for underwater cleaning of a ship’s hull (9) from growth (11) by marine organisms, comprising: - an ultrasonic plate oscillator (1), - a frame (4) formed in one plane and closed all around, - at least three magnetic positioning and fastening actuators (3) attached to the frame (4), and - a control and regulation unit, characterized by that the cleaning module further comprises: - several hexapod actuators (2) connecting the ultrasonic plate oscillator (1) and the frame (4) to form a hexapod, - a suction device (5) surrounding the ultrasonic plate oscillator (1) for sucking off the growth (11) detached from the ship's hull (9), and - a sensor unit designed to detect the position on the ship's hull (9) and to detect the distance of the ultrasonic plate oscillator (1) from the ship's hull (9), wherein the at least three magnetic positioning and fastening actuators (3) attached to the frame (4) are designed for positioning and magnetically fixing the hexapod to the ship's hull (9) and for adjusting the distance of the hexapod to the ship's hull (9), and wherein the control and regulation unit is arranged to control the position and orientation of the ultrasonic plate oscillator (1) relative to the ship's hull (9) and to regulate the distance of the ultrasonic plate oscillator (1) from the ship's hull (9). [2] Cleaning module according to claim 1, characterized by that the sensor unit is further designed to detect the degree of cleaning of the ship's hull (9). [3] Cleaning module according to claim 1 or 2, characterized bythat the sensor unit further comprises sensors for monitoring the environment of the cleaning module. [4] Cleaning module according to one of claims 1 to 3, characterized by that the hexapod actuators (2) and / or the positioning and fastening actuators (3) are flow-optimized lightweight components with hybrid axes. [5] Cleaning device, characterized by that it comprises a cleaning module according to one of claims 1 to 4 for the underwater cleaning of a ship's hull (9), further comprising a line portal (7) on which the cleaning module is suspended in a height-adjustable manner, and a displacement unit (8) which is magnetically adhered to the ship's hull (9) and is linearly movable for the horizontal linear movement of the cleaning module on the ship's hull (9) which is connected to the displacement unit (8) via the line portal (7). [6] Cleaning device comprising a remotely operated underwater vehicle, characterized bythat a cleaning module according to one of claims 1 to 4 is attached to the remote-controlled underwater vehicle. [7] Cleaning process for underwater cleaning of a ship’s hull (9), characterized by that it is carried out by means of a cleaning module according to one of claims 1 to 4 in a predetermined cleaning field (12) on the ship's hull (9), wherein (a) the cleaning module is positioned and fixed on the ship's hull (9) in the area of ​​the cleaning field (12) by means of the positioning and fastening actuators (3), (b) the ultrasonic plate oscillator (1) is guided by means of the hexapod actuators (2) over the area of ​​the cleaning field (12), by controlling the hexapod actuators (2) and the positioning and fastening actuators (3) parallel to the ship's hull (9) at a distance of 100 ± 20 mm, whereby the growth (11) is removed from the ship's hull (9) by means of the ultrasound emitted by the ultrasonic plate oscillator (1), (c) the detached growth (11) is sucked off by means of the suction device (5). [8] Cleaning method according to claim 7, characterized by that the frequency of the ultrasound emitted by the ultrasonic plate oscillator (1) is in the range of 20 kHz to 25 kHz. [9] Cleaning method according to claim 7 or 8, carried out with a cleaning device according to claim 5, characterized byin that the linearly movable movement unit (8) which is magnetically adhered to the ship's hull (9) is moved with a permanent, horizontal movement along the ship's hull (9) in order to move the cleaning module horizontally to the respective cleaning field (12) on the ship's hull (9), wherein during this horizontal movement of the movement unit (8) the cleaning module is temporarily fixed to the respective cleaning field (12), wherein the relative movement of the movement unit (8) to the temporarily fixed cleaning module is compensated by means of the line portal (7), and wherein the cleaning module is moved vertically on the ship's hull (9) by means of the line portal (7) for height positioning in the area of ​​the respective cleaning field (12). [10] Cleaning method according to claim 7 or 8, carried out with a cleaning device according to claim 6, characterized by that the respective cleaning field (12) is approached by means of the remote-controlled vehicle.

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