WO2024256723A1

WO2024256723A1 - High pressure jetting device for cleaning steel surfaces

Info

Publication number: WO2024256723A1
Application number: PCT/EP2024/066796
Authority: WO
Inventors: Gijsbert Christiaan SLINGERLAND
Original assignee: Derc Waterjetting B.V.
Priority date: 2023-06-16
Filing date: 2024-06-17
Publication date: 2024-12-19
Also published as: NL2035114B1

Abstract

A cleaning device (1) for cleaning a steel workpiece the device comprising: a carrier (20), comprising a plurality of traction wheels (21) for moving the device over the workpiece and comprising a magnet for coupling the carrier to the workpiece, a cleaning head (10), attached to the carrier and arranged in front of the carrier, a lever assembly (30), functionally arranged in between the carrier and the cleaning head and configured to press the cleaning head against the workpiece during use of the device, the lever assembly comprising: an inner lever arm (31), fixedly attached to the carrier and projecting in front of the carrier, an outer lever arm (32), rotatably connected to the inner lever arm and rotatably connected to the cleaning head, and a pretension device (33), configured to exert a pretension force between the inner lever arm and the outer lever arm for pressing the cleaning head against the workpiece.

Description

Title: High pressure jetting device for cleaning steel surfaces

Field of the invention

The present invention relates to a cleaning device for cleaning steel workpieces, such as a hull of a ship. The present invention further provides a method of cleaning a steel workpiece, for example of removing paint from a hull of a ship and/or of removing contamination from an upright wall.

State of the art

At present, various types of cleaning devices are known for cleaning workpieces. In certain applications, the workpieces that are to be cleaned are made of a steel and are aligned upright in a plane having at least a component extending vertically. Examples hereof are storage tanks for oil products and hulls of ships.

To this effect, cleaning devices have been developed which comprise a carrier with a plurality of wheels and with a magnet, configured to exert a magnetic attractive force on the workpiece during use. The magnetic attractive force pulls the cleaning device to the workpiece during use, while the wheels to rest against the workpiece. The cleaning device is configured to subject one or more of its wheels to a traction force, to drive the cleaning device over the workpiece in a movement direction having at least a component parallel to a vertical direction, under constant attraction by the magnetic attractive force to prevent the cleaning device from falling. An example of such a magnetic cleaning device is disclosed in US 2021/107138 A1. The known cleaning devices further comprise a cleaning head, comprising spraying nozzles and configured to be moved over the surface of the workpiece, and a lever assembly for connecting the carrier and the cleaning head to each other.

The known magnetic cleaning device has the drawback that the construction of its cleaning head only allows limited mutual movements between the carrier and the cleaning head. This limited degree of movement may be sufficient for the cleaning of oil storage tanks, which are curved to a minor extent only. However, it was found by the applicant that the known cleaning devices may not be enable sufficient cleaning of surfaces that are curved to a larger extent, such as the undersides of ship hulls.

Object of the invention

It is therefore an object of the invention to provide a cleaning device that is able to clean curved workpieces to a better extent, or at least to provide an alternative cleaning device. Detailed description

The present invention provides a cleaning device for cleaning steel workpieces, such as a hull of a ship, the device comprising: a carrier, comprising a plurality of traction wheels for moving the device over the workpiece in a movement direction and comprising a magnet for coupling the carrier to the workpiece under influence of magnetic forces, a cleaning head, attached to the carrier and arranged in front of the carrier, seen along the movement direction, a lever assembly, functionally arranged in between the carrier and the cleaning head and configured to press the cleaning head against the workpiece during use of the device, wherein at least part of the traction wheels are spread apart in the movement direction to define at least two traction wheel axles aligned perpendicular to the movement direction, and wherein the cleaning head comprises a plurality of support wheels, configured to roll over the workpiece during use, characterized in that the lever assembly comprises: an inner lever arm, attached to the carrier and projecting in front of the carrier, seen along the movement direction, an outer lever arm, rotatably connected to the inner lever arm and rotatably connected to the cleaning head, and a pretension device, preferably functionally arranged between the inner lever arm and the outer lever arm, and configured to exert a pretension force between the inner lever arm and the outer lever arm for pressing the cleaning head against the workpiece.

The present invention thus provides a cleaning device with a magnetic carrier, being able to be coupled to a steel workpiece under influence of magnetic forces. The magnet of the carrier may be embodied as a permanent magnet or as an electromagnet, being configured to emit an electromagnetic field to couple the carrier to the steel workpiece.

The traction wheels of the carrier are configured to enable rolling of the carrier over the workpiece, which rolling generally takes place in a movement direction, i.e. a linear movement direction, for example aligned parallel to a vertical direction. The carrier is further able to make turns, for example by rotating the wheels at different rotational velocities, to allow the carrier to turn in a manner similar as tracked vehicles.

Seen in the movement direction, the traction wheels are spaced apart to define the two spaced traction wheel axles of the carrier, which are placed at a distance from each other in the movement direction. Each traction wheel axle is composed of at least one traction wheel that is configured to rotate about an axis of rotation aligned in a transverse direction, aligned perpendicular to the movement direction and parallel to the surface of the workpiece. The carrier may for example comprise two traction wheel axles, each having two traction wheels, giving a total of four traction wheels. The spaced traction wheel axles may provide the benefit that the carrier is more stable against forward and backward tilting under influence of the cleaning head being pressed on and moved over the surface of the workpiece.

The cleaning head itself is located in front of the carrier, seen in the movement direction. During use of the cleaning device, the cleaning head is moved over the workpiece surface that is to be cleaned first, so that the traction wheels of the carrier always roll over cleaned parts of the workpiece. This may offer the benefit that, compared to rolling over surfaces that are still to be cleaned, the wheels directly contact the cleaned steel, which may improve the magnetic attraction and traction force of the carrier.

The cleaning head may comprise a rotary nozzle, being configured to jet high-pressure fluid onto the surface of the workpiece, in order to ablate contaminations and to remove coating layers from the workpiece. The rotary nozzle may be accommodated underneath an enclosed cover, to seal the interior of the cleaning head from the surroundings of the cleaning device, in order to prevent the surroundings from being contaminated with possibly polluted fluids from the cleaning head.

The cleaning head comprises a plurality of support wheels, which are configured to rest on and to roll over the surface of the workpiece, to form a rigid support for the cleaning head and to allow the cleaning head to be firmly pressed on the workpiece surface, whilst safeguarding a constant and desired spacing between the cleaning head, i.e. the cover and/or the nozzle, and the workpiece surface.

The cleaning head is attached to the carrier by means of a lever assembly. The lever assembly is connected to the carrier and to the cleaning head, being configured to move the cleaning head relative to the carrier and to press the cleaning head against the workpiece during use. The pressing against the workpiece is desired to obtain the best possible cleaning result and to prevent leakage of contaminated fluids.

The lever assembly of the present cleaning device comprises an inner lever arm, an outer lever arm and a pretension device. The inner lever arm may be fixedly connected to the carrier, or may even be part of the carrier, i.e. integrally connected thereto. This inner lever arm is configured to remain substantially stationary relative to the carrier, i.e. at least stationary to prevent rotations parallel about axes parallel to the axis of rotation, so that the entire weight of the carrier and that the magnetic attractive force can be transmitted to the cleaning head, via the inner lever arm, to press the cleaning head against the workpiece.

The inner lever arm projects in front of the carrier, so that the lever assembly is arranged in front of the carrier as well. The outer lever arm of the lever assembly is connected to the inner lever arm, projecting in front of the carrier to an even further extent. The outer lever arm is also rotatably connected to the cleaning head, enabling mutual rotations between the cleaning head and the outer lever arm. These mutual rotations between the lever arms and the cleaning head may be defined around axes of rotation parallel to the transverse direction, so that the rotations enable forward and backward tilting of the cleaning head relative to the workpiece, seen with respect to the movement direction.

The present cleaning device thus comprises a lever assembly with two lever arms that are freely rotatable relative to each other, in the absence of blocking means between them for blocking mutual rotations during use. The rotatable connections between the lever arms provide a larger degree of movement for the cleaning head, so that the cleaning head is able to accurately follow the contours of the workpiece. The same holds for the rotatable connection between the cleaning head and the outer lever arm, which is free of blocking means for blocking rotations as well, which enables mutual rotations between them to further improve following of the workpiece by the cleaning head, to enable improved cleaning of curved workpieces.

The lever assembly of the present cleaning device finally comprises the pretension device, configured to exert a pretension force between the inner lever arm and the outer lever arm for pressing the cleaning head against the workpiece. The pretension device may comprise a spring or a gas spring and may be configured to exert a compressive pretension force between inner lever arm and the outer lever arm, in order to push the outer lever arm, i.e. an outer end thereof, towards the workpiece, so that the cleaning head is pressed against the workpiece. As indicated, the magnetic attraction forces between the carrier and the workpiece thereby serve to counter the pressing of the cleaning head against the workpiece, by holding, i.e. pulling the carrier towards the workpiece. The pretension device may be functionally arranged between the inner lever arm and the outer lever arm, for example directly connected to the respective lever arms by means of rotatable connections, in order to directly act on the lever arms.

In an embodiment, the support wheels may each comprise a support wheel body and a plurality of rollers that are spread over the perimeter of the support wheel body. The rollers are able to rotate relative to the support wheel body around an axis perpendicular to the axis of rotation of the support wheel body. The rollers may roll over the workpiece surface when the carrier is making a sideward turn, whereas the support wheel bodies may then remain stationary relative to the cleaning head.

Alternatively, the support wheels of the cleaning head may be pivotable support wheels, which are configured to pivot around a pivot axis perpendicular to the surface of the workpiece, so that they are able to follow movements of the carrier, for example when the carrier is making a turn. In an embodiment, at least part of the support wheels are spread apart in the movement direction to define at least two support wheel axles aligned perpendicular to the movement direction. Each support wheel axle is thereby composed of at least one support wheel that is configured to rotate about an axis of rotation aligned perpendicular to the movement direction.

During use, the support wheels substantially take up all forces exerted by the lever assembly pressing the cleaning head against the workpiece surface, which implies that the cover of the cleaning head itself no longer has to provide a significant contribution in this functionality, as it is the case in existing cleaning devices. This enables the present cover to be optimized for sealing against the workpiece surface, for example allowing the cleaning head to be provided relatively flexible to follow the contours of the workpiece, whereas existing cleaning head covers without support wheels needed to be relatively rigid, and thus inflexible, for transferring the forces from the lever assembly onto the workpiece.

The cleaning head may for example comprise two support wheel axles, each having two support wheels, giving a total of four support wheels. The spaced support wheel axles may provide the benefit that the cleaning head is more stable against forward and backward tilting over the surface of the workpiece.

Seen in the movement direction, the cleaning head may comprise two support wheels at a frontal end, which are spaced apart in the transverse direction. Likewise, the cleaning head may comprise two support wheels at a rear end as well, which are also spaced apart in the transverse direction. The four support wheels may thereby be arranged in a rectangular, for example a square pattern. Such a support wheel pattern may offer a rigid support for the cleaning head, upon being pressed on the surface of the workpiece, to enable the cleaning head to accurately follow the contours of the workpiece to improve cleaning thereof.

Alternatively, the cleaning head may comprise three support wheels, with either two spaced support wheels at its frontal end and a single support wheel at its rear end, or with a single support wheel at its frontal end and two spaced support wheels at its rear end.

In a further embodiment, the outer lever arm is rotatably connected to the cleaning head centrally in between the support wheel axles, seen along the movement direction. The lever assembly thereby joins the cleaning head centrally in between the support wheels, for example centrally in the rectangular support wheels pattern. This may enable that the cleaning head is pressed on the workpiece via all support wheels during use, which may improve the stability of the cleaning head during use and which may further improve following of the workpiece contour to improve cleaning thereof.

In an embodiment, the cleaning head comprises a bridging member, extending substantially in the movement direction, wherein the support wheels are arranged on opposite ends of the bridging member, and wherein the outer lever arm is rotatably connected to a central portion of the bridging member. The bridging member forms a connection between the support wheels and the outer lever arms, to transmit the pretension forces from the outer lever arm towards the support wheels for pressing the cleaning head against the workpiece surface.

The bridging member may extend over and/or around the cover of the cleaning head, so that the cover may not need to perform a structural function for the cleaning head. The bridging member thereby serves to transfer all forces from the lever assembly, which means that the cover is substantially bypassed in terms of transferring forces from the lever assembly towards the workpiece surface. This enables the cover to be optimized for closing- off the interior of the cleaning head against the workpiece surface, for example allowing the cover to be made relatively flexible to follow the contours of the workpiece.

The cleaning device according to this embodiment may comprise two of the bridging members extending in the movement direction. Each of the bridging members may be associated with a respective frontal support wheel, arranged at the frontal end of the cleaning head, with a respective rear support wheel, arranged at the rear end of the cleaning head, and with a respective outer lever arm of the lever assembly.

The two bridging members may be mirror images of each other in the transverse direction. The provision of the bridging members, for example being mirror images of each other, may provide a further benefit for following the contours of the workpiece with the cleaning head, by sideward tilting, to further improve cleaning of the workpiece.

In an embodiment, the outer lever arm extends between an inner end, located proximate to the carrier, and an opposed outer end, the inner lever arm is rotatably connected to the outer lever arm at the inner end thereof, the cleaning head is rotatably connected to the outer lever arm at the outer end thereof, the outer lever arm comprises an outer attachment point, which is spaced at a distance from a straight line between the inner end and the outer end of the outer lever arm, and the pretension device is rotatably connected to the outer lever arm at the outer attachment point.

According to this embodiment, the outer lever arm may have, at least in terms of function, a triangular shape between its inner end, its outer end and the outer attachment point. Hence, a straight line may be drawn virtually between the inner end and the outer end of the outer lever arm, which line forms one side of the virtual triangle. Other sides of the virtual triangle are formed by respective virtual lines between the inner end of the outer lever arm and the outer attachment point and between the outer end of the outer lever arm and the outer attachment point. As such, the pretension device may not need to extend substantially adjacent to the outer lever arm, but instead at a distance therefrom. This spacing may give rise to a lever arm for the pretension force exerted by the pretension device, in order to increase the force acting on the cleaning head for pressing the cleaning head on the workpiece surface.

In a further embodiment, the outer attachment point is located substantially vertically above the outer end of the outer lever arm. With the term ‘vertically above’ it is at least meant that the outer attachment point is located vertically higher than the outer end of the outer lever arm. The outer attachment point may be horizontally offset relative to the outer end of the outer lever arm, or both may be positioned above each other. The vertical spacing may be beneficial to increase the lever arm at which the pretension device is arranged, in order to increase the torque generated by the pretension device and to maximize the force at which the cleaning head is pressed against the workpiece surface.

As such, the pretension device extends vertically above and optionally substantially parallel to the outer lever arm. Furthermore, especially where the outer attachment point is positioned directly above the outer end of the outer lever arm, the length of the pretension device may be increased, which may enable an increase in stroke length of the pretension device and/or a further increase in the pretension force.

In an embodiment, the inner lever arm extends between an inner end and an opposed outer end, the inner lever arm is connected to the carrier with its inner end, the outer lever arm is rotatably connected to the inner lever arm at the outer end thereof, the inner lever arm comprises an inner attachment point, which is spaced at a distance from a straight line between the inner end and the outer end of the inner lever arm, and the pretension device is rotatably connected to the inner lever arm at the inner attachment point.

According to this embodiment, the inner lever arm may have, at least in terms of function, a triangular shape between its inner end, its outer end and the inner attachment point. Hence, a straight line may be drawn virtually between the inner end and the outer end of the inner lever arm, which line forms one side of the virtual triangle. Other sides of the virtual triangle are formed by respective virtual lines between the inner end of the inner lever arm and the inner attachment point and between the outer end of the inner lever arm and the inner attachment point.

As such, the pretension device may not need to extend substantially adjacent to the inner lever arm, but instead at a distance therefrom. This spacing may give rise to a lever arm for the pretension force exerted by the pretension device, in order to increase the force acting on the cleaning head for pressing the cleaning head on the workpiece surface. In a further embodiment, the inner attachment point is located substantially vertically above the inner end of the inner lever arm. With the term ‘vertically above’ it is here at least meant that the inner attachment point is located vertically higher than the inner end of the inner lever arm. The inner attachment point may be horizontally offset relative to the inner end of the inner lever arm, or both may be positioned above each other. The vertical spacing may be beneficial to increase the lever arm at which the pretension device is arranged, in order to increase the torque generated by the pretension device and to maximize the force at which the cleaning head is pressed against the workpiece surface.

As such, the pretension device extends vertically above and optionally substantially parallel to the inner lever arm. Furthermore, especially where the inner attachment point is positioned directly above the inner end of the inner lever arm, the length of the pretension device may be increased, which may enable an increase in stroke length of the pretension device and/or a further increase in the pretension force.

In an alternative embodiment, the outer lever arm extends between an inner end, located proximate to the carrier, and an opposed outer end, the inner lever arm is rotatably connected to the outer lever arm at a central portion thereof, located centrally in between its inner end and outer end, the cleaning head is rotatably connected to the outer lever arm at the outer end thereof, and the pretension device is rotatably connected to the outer lever arm at the inner end thereof.

According to this embodiment, the inner lever arm extends from the carrier towards the front, seen in the movement direction, and is connected to the central portion of the outer lever arm. The outer lever arm pivots around the inner lever arm, being connected to the pretension device at its inner end and to the cleaning head at its outer end.

This configuration of the lever assembly may provide the benefit that the forces acting on the outer lever arm are balanced around the rotation point with the inner lever arm. Hence, one side of the outer lever arm, i.e. the inner end thereof, is subjected to forces from the pretension device and the other side of the outer lever arm, i.e. the outer end thereof, is subjected to forces acting on the cleaning head for pressing the cleaning head on the workpiece surface.

In a further alternative embodiment, the inner lever arm extends between an inner end and an opposed outer end, the inner lever arm is connected to the carrier with its inner end, the outer lever arm is rotatably connected to the inner lever arm at the outer end thereof, and the pretension device is rotatably connected to the inner lever arm at a central portion thereof, located centrally in between its inner end and outer end. According to this embodiment, the pretension device extends from the central portion of the inner lever arm, for example extending towards the inner end of the outer lever arms. The pretension device is thus provided somewhat forward, away from the carrier. This may enable the pretension device from rotating the outer lever arm relative to the inner lever arm to a larger extent. The pretension device may thereby extend substantially perpendicular to the workpiece surface, so that all forces acting on the outer member extend substantially perpendicular to the workpiece surface.

Alternatively, the pretension device may be connected to the inner end of the inner lever arm, i.e. adjacent the carrier.

In an embodiment, the cleaning device comprises two of the lever assemblies, each comprising the respective inner lever arm, outer lever arm and pretension device, and the lever assemblies are mirror images of each other, seen with respect to a symmetry plane parallel to the movement direction. Both lever assemblies may thereby be arranged next to each other in the transverse direction, so that the cleaning head is pressed on the workpiece on two opposite sides, which enables the cleaning head to better follow the contours of the workpiece, to improve the cleaning of the workpiece.

In a further embodiment, the cleaning head comprises two of the bridging members, each comprising two of the support wheels, and the bridging members are mirror images of each other, seen in the symmetry plane.

According to this embodiment, each of the lever assemblies is associated with a respective one of the bridging members, so that each of the combined lever assemblies and bridging members presses the cleaning head against the workpiece surface on opposed sides. This may further improve the stability of the cleaning head on the workpiece surface, to further improve the cleaning.

In an additional or alternative embodiment, the lever assemblies, e.g. the inner lever arms, outer lever arms and pretension devices thereof, are movable independent of each other. This may allow the cleaning head to tilt sidewardly relative to the movement direction. Sideward tilting of the cleaning head, in addition to the forward and backward tilting of the cleaning head under influence of its rotatable connection to the outer lever arms, may further enable the cleaning head to follow the contours of the workpiece, to further improve cleaning thereof. If, for example, the cleaning head is tilted to the right, the right lever assembly may press the cleaning head lower than the left lever assembly. Likewise, left tilting of the cleaning head may involve that the left lever assembly pressed the cleaning head lower than the right lever assembly. The presence of multiple support wheels axles may advantageously provide that at least two support wheels are pressed against the workpiece surface simultaneously, i.e. independent of a tilting orientation of the cleaning head; For example, at least two diagonally opposite support wheels may contact the workpiece surface, or two straight opposite, e.g. in the movement direction, may contact the workpiece surface to provide for a rigid support.

In an embodiment, the outer lever arm is connected to the cleaning head through a multiaxial hinged connection, configured to enable forward and backward tilting and sideward tilting of the cleaning head, seen along the movement direction. The multiaxial hinged connection between the outer lever arm and the cleaning head may allow for mutual tilting between the outer lever arm and the cleaning head about multiple orthogonal axes of rotation, to more accurately follow the contours of the workpiece, to further improve cleaning thereof.

The provision of the multiaxial hinged connection may be beneficial where the cleaning device comprises the two lever assemblies and/or the two bridging members. This enables each lever assembly and associated bridging member to be moved independently of each other, for example allowing either side of the cleaning head to be pressed lower than the other side, to enable sideward tilting of the cleaning head to follow the contours of the workpiece, to further improve cleaning thereof.

In an additional or alternative embodiment, the inner lever arm is rotatably attached to the carrier, wherein the inner lever arm is rotatable relative to the carrier about a sideward rotation axis parallel to the movement direction of the device. This sideward rotation of the inner lever arm may enable that the cleaning head of the cleaning device is able to follow sideward curvatures of the workpiece surface. Should the cleaning device comprise multiple lever assemblies, the inner lever arms may be connected rotatably to the carrier individually, to each rotate about their own sideward axis of rotation, or may be jointly rotatably connected to the carrier, to jointly rotate about a common sideward axis of rotation.

In an embodiment, the pretension device is a gas spring. Gas springs are typically compressive springs that have been found to be convenient for use in the present cleaning device, because their spring force is relatively constant, irrespective of the degree of compression. The gas spring may, for example, extend in between the central portion of the inner lever arm and the inner portion of the outer lever arm, being configured to push both portions away from each other.

In an embodiment, lever assembly comprises a manually operable handle, which is functionally arranged in between the pretension device, e.g. the gas spring, and the inner lever arm and/or in between the pretension device, e.g. the gas spring, and the outer lever arm, wherein the handle is configured to lift the cleaning head from the workpiece surface, for example after use of the cleaning device.

In an embodiment, wherein an axis of rotation of the rotatable connection between the inner lever arms and the outer lever arms projects over the cleaning head. This means that the length of the outer lever arm, i.e. the length from the rotatable connection towards its connection with the cleaning head, can be as short as possible. As such, the short length may provide the effect that the outer lever arm may rotate over a relatively large angle relative to the inner lever arm, allowing the cleaning head to follow relatively large curvatures and height difference in the workpiece, whilst maintaining a large force pretensioning it against the workpiece.

In an embodiment, the cleaning head comprises a rotary nozzle, facing the workpiece and configured to jet a pressurized fluid towards the substrate. The pressurized fluid can thereby be jetted onto the surface of the workpiece, in order to ablate contaminations and to remove coatings from the workpiece.

In a further embodiment, the cleaning head further comprises a cover, defining a cleaning head interior in which the nozzle is arranged, and a flexible seal device, located underneath the cover and configured to be pressed against the workpiece for closing-off the cleaning head interior against the workpiece. The rotary nozzle may be accommodated underneath the enclosed cover, to seal the interior of the cleaning head from the surroundings of the cleaning device, in order to prevent the surroundings from being contaminated with polluted fluid from the cleaning head.

The flexible seal device is configured to follow the contours of the workpiece to obtain a seal between the cover and the workpiece, to prevent fluid and contaminants from escaping. The flexible seal device may be pretensioned against the workpiece during use, for example being elastically compressed when pressed against the workpiece. The compression may exert a pretensioning force of the sealing device against the workpiece.

To this effect, the flexible seal device may comprise an annular bellow, arranged underneath the perimeter of the cover and configured to be compressed when the cleaning head is pressed against the workpiece.

The flexible seal device may further comprise an annular wear ring underneath the bellow, which is configured to be in direct contact with the workpiece during use of the cleaning device. The wear ring can be made of a wear-resistant material, in order to prevent wear from sliding over the workpiece surface whilst the cleaning head is pressed against the workpiece.

In an embodiment, the cleaning device may comprise suction means, emerging from the interior of the cleaning head, i.e. underneath the cover, to remove fluid and contaminants from the interior of the cleaning head. The suction means may thereto generate a vacuum underneath the cover, in the interior of the cleaning head, which vacuum may further contribute in pressing the cleaning head against the workpiece.

In an embodiment, the cover is solely attached to the bridging member and located centrally in between the support wheels. This embodiment may enable that the cleaning head is pressed against the workpiece via the support wheels, which serve to counter the forces at which the cleaning head is pretensioned against the workpiece. No significant forces may be transmitted via the cover itself, although the cover may be pressed against the workpiece somewhat to establish a proper seal against the workpiece.

The reduced forces acting on the cover may allow for an improved flexibility thereof, thus allowing improved sealing. Furthermore, the wear of the cover may be reduced, thus improving lifespan. Finally, the surrounding support wheels may allow for a more constant pretensioning of the cover against the workpiece, thus allowing for improved cleaning of the workpiece.

The present invention further provides a cleaning head for use in a cleaning device according to the present invention.

The cleaning head according to the present invention may comprise one or more of the features and/or benefits disclosed herein in relation to the cleaning device according to the present invention, for example as recited in the appended claims.

The present invention finally provides a method of cleaning a steel workpiece, for example of removing paint from a hull of a ship and/or of removing contamination from an upright wall, the method comprising the steps of: providing a cleaning device as disclosed herein, arranging the cleaning device on the workpiece with its carrier, coupling the cleaning device to the workpiece by means of the magnet, pressing the cleaning head against the workpiece under influence of the pretension force, and moving the cleaning device over the workpiece whilst jetting a pressurized fluid towards the workpiece with a rotary nozzle of the cleaning head.

The method according to the present invention may further comprise one or more of the features and/or benefits disclosed herein in relation to the cleaning device according to the present invention, for example as recited in the appended claims.

According to the present method, first, the cleaning device is arranged on the workpiece. The cleaning device may, but not necessarily needs to, be placed on a horizontal portion of the workpiece. Instead, the cleaning device may also be held against a portion of the workpiece at least having a component extending vertically.

Next, the coupling of the cleaning device to the workpiece may be effected by establishing the magnetic attraction force from the magnet in the carrier to hold the cleaning device against the workpiece without falling. The coupling may take place by activating an electromagnet in the carrier, i.e. by subjecting it to an alternating electric current, to emit the electromagnetic field required for magnetically attracting the carrier of the cleaning device to the workpiece.

The cleaning head is thereafter pressed against the workpiece, so that the interior of the cleaning head is sealed against the workpiece, to prevent fluids and contaminants inside the cleaning head interior from escaping. The pretension force that presses the cleaning head against the workpiece is furthermore counteracted by the magnetic attraction force between the carrier and the workpiece.

Finally, the cleaning device is configured to jet pressurized fluid, e.g. water, from its nozzle to remove contaminants and/or coating layers from the workpiece surface. Meanwhile, the cleaning device is rolled over the workpiece, to enable the cleaning head with pressurized fluid to go over substantially the entire surface of the workpiece.

The workpiece may have a curved surface, for example curved irregularly. The cleaning device used in the present method comprises a cleaning head that is able to accurately follow the surface of the workpiece, to be able to clean the workpiece in an improved manner.

Brief description of drawings

Further characteristics of the invention will be explained below, with reference to embodiments, which are displayed in the appended drawings, in which:

Figure 1 schematically depicts an embodiment of the cleaning head of the cleaning device according to the present invention,

Figure 2 schematically depicts an embodiment of the cleaning device according to the present invention, arranged on a workpiece with a flat surface, Figure 3 schematically depicts the cleaning device of figure 2, arranged on a workpiece with a concave surface,

Figure 4 schematically depicts the cleaning device of figure 2, arranged on a workpiece with a convex surface, and

Figure 5 schematically depicts an alternative embodiment of the cleaning device according to the present invention.

Throughout the figures, the same reference numerals are used to refer to corresponding components or to components that have a corresponding function.

Detailed description of embodiments

Figure 1 schematically depicts an embodiment of the cleaning head of the cleaning device according to the present invention, to which cleaning head is referred to with reference numeral 10. An embodiment of the present cleaning device is shown in figures 2 - 4 and is referred to with reference numeral 1.

The present cleaning device 1 is intended for cleaning steel workpieces 100. The device 1 comprises a carrier 20, comprising a plurality of traction wheels 21 for moving the device 1 over the workpiece 100 in a movement direction M and comprising a magnet for coupling the carrier 20 to the workpiece 100 under influence of magnetic forces F. The magnet is an electromagnet, arranged inside the carrier and not visible in the figures, which magnet is configured to emit an electromagnetic field to couple the carrier 20 to the steel workpiece 100.

The traction wheels 21 are configured to enable rolling of the carrier 20 over the workpiece 100. Seen in the movement direction M, the traction wheels 21 are spaced apart to define the two spaced traction wheel axles 22 of the carrier 20, which are placed at a distance from each other in the movement direction M. Each traction wheel axle 22 is composed of two traction wheels 21 , giving a total of four traction wheels 21.

The cleaning head 10 is attached to the carrier 20 by means of two lever assemblies 30 and is arranged in front of the carrier 20, seen along the movement direction M. The lever assemblies 30 are each configured to press the cleaning head 10 against the workpiece 100 during use of the device 1. During use of the cleaning device 1 , the cleaning head 10 is moved over the workpiece surface 101 that is to be cleaned first, so that the traction wheels 21 of the carrier 20 always roll over cleaned parts 102 of the workpiece 100.

The cleaning head 10 comprises a rotary nozzle, not visible in the figures, being configured to jet high-pressure fluid onto the surface of the workpiece 100, in order to ablate contaminations and to remove coating layers from the workpiece 100. The cleaning head 10 further comprises a cover 11 , defining a cleaning head interior in which the nozzle is arranged. The cleaning head 10 further comprises a flexible seal device, located underneath the cover 11 and configured to be pressed against the workpiece 100 for closing-off the cleaning head interior against the workpiece 100. The flexible seal device is configured to follow the contours of the workpiece 100 to obtain a seal between the cover 11 and the workpiece 100, to prevent fluid and contaminants from escaping. To this effect, the flexible seal device comprises an annular bellow 12, arranged underneath the perimeter of the cover 11 and configured to be compressed to be pretensioned against the workpiece 100 during use. The flexible seal device further comprises an annular wear ring 13 underneath the bellow 12, which is configured to be in direct contact with the workpiece 100 during use of the cleaning device 1.

The lever assemblies 30 are mirror images of each other, seen with respect to a symmetry plane parallel to the movement direction M. Both lever assemblies 30 are connected to the carrier 20 and to the cleaning head 10 and each comprise an inner lever arm 31, an outer lever arm 32 and a pretension device, embodied as a gas spring 33. The inner lever arm 31 is fixedly connected to the carrier 20 and is configured to remain stationary relative to the carrier 20, so that the entire weight of the carrier 20 and that the magnetic attractive force F can be transmitted to the cleaning head 10 to press the cleaning head 10 against the workpiece 100.

The inner lever arm 31 projects in front of the carrier 20 and the outer lever arm 32 is connected to the inner lever arm 31, projecting in front of the carrier 20 to an even further extent. An axis of rotation of a rotatable connection 34 between the inner lever arms 31 and the outer lever arms 32 projects over the cleaning head 10.

The outer lever arm 32 is also rotatably connected to the cleaning head 10, enabling mutual rotations between the cleaning head 10 and the outer lever arm 32. These mutual rotations are defined around axes of rotation parallel to a transverse direction, perpendicular to the movement direction M and the plane of the drawings of figures 2 - 4, so that the rotations enable forward and backward tilting of the cleaning head 10 relative to the workpiece 100.

The gas springs 33 of the lever assemblies 30 are configured to exert a pretension force between the inner lever arm 31 and the outer lever arm 32 for pressing the cleaning head 10 against the workpiece 100. The gas springs 33 are attached to the inner lever arm 31 via respective handles 35, which can be manually operated lift the cleaning head 10 from the workpiece 100, for example after use of the cleaning device 10.

The inner lever arm 31 extends between an inner end 311 and an opposed outer end 312. The inner lever arm 31 is fixedly connected to the carrier 20 with its inner end 311 and the outer lever arm 32 is rotatably connected to the inner lever arm 31 at the outer end 312 thereof. The inner lever arm 31 comprises an inner attachment point, which is provided on an inner strut 36 that is integrally connected to the inner lever arm 31 itself. The gas spring 33 is, via the handle 35, attached to the inner lever arm 31 via the inner attachment point. The inner attachment point on the inner strut 36 is located substantially above the first end 311 of the inner lever arm 31, so that the gas spring 33 extends vertically above at a distance from the inner lever arm 31, i.e. at a distance from a virtual straight line between the inner end 311 and the outer end 312 thereof.

The outer lever arm 32 extends between an inner end 321, located proximate to the carrier 20, and an opposed outer end 323. The inner lever arm 31 is rotatably connected to the outer lever arm 32 at the inner end thereof 321. The cleaning head 10 is rotatably connected to the outer lever arm 32 at the outer end 322 thereof. The outer lever arm 32 comprises an outer attachment point, which is provided on an outer strut 37 that is integrally connected to the outer lever arm 32 itself. The gas spring 33 is attached to the outer lever arm 32 via the outer attachment point. The outer attachment point on the outer strut 37 is located substantially above the second end 321 of the outer lever arm 32, so that the gas spring 33 extends vertically above at a distance from the outer lever arm 32, i.e. at a distance from a virtual straight line between the inner end 321 and the outer end 322 thereof.

Seen in a horizontal direction, e.g. along the movement direction M, the gas springs 33 have a length corresponding to the overall length of the lever assemblies 30. Hence, the gas springs 33 extend from above the inner end 311 of the inner lever arm 31 towards the outer end 322 of the outer lever 32. By having this length of the gas spring 33 maximized, the stroke length thereof may be maximized accordingly.

The cleaning head 10 comprises a four support wheels 14, which are configured to rest on and to roll over the surface of the workpiece 100, to form a rigid support for the cleaning head 10 and to safeguard a constant and desired spacing between the cleaning head 10, i.e. the nozzle therein, and the workpiece 100. The support wheels 14 each comprise a support wheel body 15 and a plurality of rollers 16 that are spread over the perimeter of the support wheel body 15. The rollers 16 are able to rotate relative to the support wheel body 15 to roll over the workpiece 100 when the carrier 20 is making a sideward turn, during which turning the support wheel body 15 itself remains stationary.

The support wheels 14 are spread apart in the movement direction M to define two support wheel axles 17 aligned perpendicular to the movement direction M. Each support wheel axle 17 comprises two support wheels 14, giving a total of four support wheels 14. Two of the support wheels 14 are located at a frontal end of the cleaning head 10 and two of the support wheels 14 are arranged at a rear end of the cleaning head 10 as well. The four support wheels 14 are thereby be arranged in a square support wheel pattern, seen from above in a direction perpendicular to the workpiece 100. The outer lever arm 32 is rotatably connected to the cleaning head 10 centrally in between the support wheel axles 17, seen along the movement direction M. The lever assemblies 30 thereby join the cleaning head 10 centrally in between the support wheels 14.

The cleaning head 10 comprises two bridging members 18, which extend substantially in the movement direction M, above the cover 11. The support wheels 14 are arranged on opposite ends of the bridging member 18 and the outer lever arm 32 of each lever assembly 30 is rotatably connected to a central portion of the bridging member 18. The bridging members 18 thereby form a connection between the support wheels 14 and the outer lever arms 32, to transmit the pretension forces from the outer lever arm 32 towards the support wheels 14 for pressing the cleaning head 10 against the workpiece 100. The bridging members 18 thereby serve to transfer all forces from the lever assemblies 30, which means that the cover 11 is substantially bypassed in terms of transferring forces from the lever assemblies 30 towards the workpiece surface 100. The two bridging members 18 are mirror images of each other in the transverse direction.

Both lever assemblies 30, e.g. the inner lever arms 31, outer lever arms 32 and gas springs 33 thereof, are movable independent of each other. This may allow the cleaning head 10 to tilt sidewardly relative to the movement direction M.

Figure 2 depicts the cleaning device 1 arranged on a workpiece 100 with a flat surface. It is visible in figure 2 that the traction wheels 21 and the support wheels 14 are in line with each other on the workpiece 100 and that the gas spring 33 is arranged in an intermediate state, being compressed to an intermediate length.

In figure 3, the cleaning device 1 is shown to have been driven to a concave part of the workpiece 100. The cleaning head 10 is shown to have been forced upward by rolling over the concave workpiece 100 with its support wheels 14. The upward movement of the outer end of the outer lever arm 32 has moved the inner end of the outer lever arm 32 in a downward direction, thereby having compressed the gas spring 33 relative to its intermediate length.

Likewise, figure 4 shows that the cleaning device 1 has been driven to a convex part of the workpiece 100. The cleaning head 10 is shown to have been forced downward under influence of the compressive force from the gas spring 33, which has been expanded to a relatively large length relative to its intermediate length. The upward movement of the inner end of the outer lever arm 32 has moved the outer end of the outer lever arm 32 in a downward direction, thereby downwardly pressing the cleaning head 10 on the workpiece 100. Figure 5 schematically depicts an alternative embodiment of the cleaning device 1. This cleaning head 10 is similar to the cleaning head shown in figures 1 - 4. However, the two lever assemblies 30 of this cleaning device 1 are embodied differently.

The gas springs 33 of the lever assemblies 30 are configured to exert a pretension force between the inner lever arm 31 and the outer lever arm 32 for pressing the cleaning head 1 against the workpiece 100.

The inner lever arm 31 extends between an inner end 311 and an opposed outer end 312. The inner lever arm 31 is fixedly connected to the carrier 20 with its inner end 311 and the outer lever arm 32 is rotatably connected to the inner lever arm 31 at the outer end 312 thereof. The gas spring 33 is rotatably connected to the inner lever arm 31 at the inner end 311.

The outer lever arm 32 extends between an inner end 321, located proximate to the carrier 20, and an opposed outer end 323. The inner lever arm 31 is rotatably connected to the outer lever arm 32 at a central portion thereof 322, located centrally in between its inner end 321 and outer end 323. The cleaning head 10 is rotatably connected to the outer lever arm 32 at the outer end 323 thereof. Furthermore, the gas spring 33 is rotatably connected to the outer lever arm 32 at the inner end 321 thereof. The support wheels 14 are spread apart in the movement direction M to define two support wheel axles 17 aligned perpendicular to the movement direction M. Each support wheel axle 17 comprises two support wheels 14, giving a total of four support wheels 14. Two of the support wheels 14 are located at a frontal end of the cleaning head 10 and two of the support wheels 14 are arranged at a rear end of the cleaning head 10 as well. The four support wheels 14 are thereby be arranged in a square support wheel pattern, seen from above in a direction perpendicular to the workpiece 100.

The outer lever arm 32 is rotatably connected to the cleaning head 10 centrally in between the support wheel axles 17, seen along the movement direction M. The lever assemblies 30 thereby join the cleaning head 10 centrally in between the support wheels 14. Both lever assemblies 30, e.g. the inner lever arms 31, outer lever arms 32 and gas springs 33 thereof, are movable independent of each other. This may allow the cleaning head 10 to tilt sidewardly relative to the movement direction M.

Claims

1. Cleaning device (1) for cleaning a steel workpiece (100), such as a hull of a ship, the device comprising: a carrier (20), comprising a plurality of traction wheels (21) for moving the device over the workpiece in a movement direction (M) and comprising a magnet for coupling the carrier to the workpiece under influence of magnetic forces (F), a cleaning head (10), attached to the carrier and arranged in front of the carrier, seen along the movement direction, a lever assembly (30), functionally arranged in between the carrier and the cleaning head and configured to press the cleaning head against the workpiece during use of the device, wherein at least part of the traction wheels are spread apart in the movement direction to define at least two traction wheel axles (22) aligned perpendicular to the movement direction, and wherein the cleaning head comprises a plurality of support wheels (14), configured to roll over the workpiece during use, characterized in that, the lever assembly comprises: an inner lever arm (31), attached to the carrier and projecting in front of the carrier, seen along the movement direction, an outer lever arm (32), rotatably connected to the inner lever arm and rotatably connected to the cleaning head, and a pretension device (33), which is functionally arranged between the inner lever arm and the outer lever arm and configured to exert a pretension force between the inner lever arm and the outer lever arm for pressing the cleaning head against the workpiece.

2. Cleaning device according to claim 1 , wherein at least part of the support wheels are spread apart in the movement direction to define at least two support wheel axles (17) aligned perpendicular to the movement direction.

3. Cleaning device according to claim 2, wherein the outer lever arm is rotatably connected to the cleaning head centrally in between the support wheel axles, seen along the movement direction.

4. Cleaning device according to claim 1 or 2, wherein the cleaning head comprises a bridging member (18), extending substantially in the movement direction, wherein the support wheels are arranged on opposite ends of the bridging member, and wherein the outer lever arm is rotatably connected to a central portion of the bridging member.

5. Cleaning device according to any of the preceding claims, wherein the outer lever arm extends between an inner end (321), located proximate to the carrier, and an opposed outer end (322), wherein the inner lever arm is rotatably connected to the outer lever arm at the inner end (321) thereof, wherein the cleaning head is rotatably connected to the outer lever arm at the outer end (322) thereof, wherein the outer lever arm comprises a outer attachment point, for example arranged on an outer strut (37), which is spaced at a distance from a straight line between the inner end and the outer end of the outer lever arm, and wherein the pretension device is rotatably connected to the outer lever arm at the outer attachment point.

6. Cleaning device according to claim 5, wherein the outer attachment point is located substantially vertically above the outer end of the outer lever arm.

7. Cleaning device according to any of the preceding claims, wherein the inner lever arm extends between an inner end (311) and an opposed outer end (312), wherein the inner lever arm is connected to the carrier with its inner end, wherein the outer lever arm is rotatably connected to the inner lever arm at the outer end thereof, wherein the inner lever arm comprises a inner attachment point, for example arranged on an inner strut (36), which is spaced at a distance from a straight line between the inner end and the outer end of the inner lever arm, and wherein the pretension device is rotatably connected to the inner lever arm at the inner attachment point.

8. Cleaning device according to claim 7, wherein the inner attachment point is located substantially vertically above the inner end of the inner lever arm.

9. Cleaning device according to any of the preceding claims, comprising two of the lever assemblies, each comprising the respective inner lever arm, outer lever arm and pretension device, and wherein the lever assemblies are mirror images of each other, seen with respect to a symmetry plane parallel to the movement direction.

10. Cleaning device according to claim 4 and claim 9, wherein the cleaning head comprises two of the bridging members, each comprising two of the support wheels, and wherein the bridging members are mirror images of each other, seen in the symmetry plane.

11. Cleaning device according to claim 9 or 10, wherein the lever assemblies, e.g. the inner lever arms, outer lever arms and pretension devices thereof, are movable independent of each other.

12. Cleaning device according to any of the preceding claims, wherein the pretension device is a gas spring.

13. Cleaning device according to any of the preceding claims, wherein the cleaning head comprises a rotary nozzle, facing the workpiece and configured to jet a pressurized fluid towards the substrate.

14. Cleaning device according to claim 13, wherein the cleaning head further comprises a cover (11), defining a cleaning head interior in which the nozzle is arranged, and a flexible seal device (12), located underneath the cover and configured to be pressed against the workpiece for closing-off the cleaning head interior against the workpiece.

15. Cleaning device according to claim 4 or 10 and claim 14, wherein the cover is solely attached to the bridging member and located centrally in between the support wheels.

16. Lever assembly for use in the cleaning device according to any of the preceding claims.

17. Method of cleaning a steel workpiece, for example of removing paint from a hull of a ship and/or of removing contamination from an upright wall, the method comprising the steps of: providing a cleaning device according to any of the claims 1 - 15, arranging the cleaning device on the workpiece with its carrier, coupling the cleaning device to the workpiece by means of the magnet, pressing the cleaning head against the workpiece under influence of the pretension force, and moving the cleaning device over the workpiece whilst jetting a pressurized fluid towards the workpiece with a rotary nozzle of the cleaning head.