WO2023149806A1

WO2023149806A1 - Cleaning head for cleaning an underwater surface

Info

Publication number: WO2023149806A1
Application number: PCT/NO2023/050028
Authority: WO
Inventors: Trond STENSLET; Erling Eriksen
Original assignee: Marine Pro As
Priority date: 2022-02-07
Filing date: 2023-02-02
Publication date: 2023-08-10
Also published as: NO20220169A1

Abstract

A cleaning head (10) for cleaning an underwater surface (3), such as a boat hull. The cleaning head has a main housing (31) with a front rim (37) that defines a front aperture facing in a surface-facing direction. A seal assembly (39) is configured to abut the underwater surface. A rotating brush (33) abuts against the underwater surface. Moreover, a brush motor (53) rotates the rotating brush (33). The position of the seal assembly (39) with respect to the position of the rotating brush (33) is adjustable along the surface-facing direction, as the cleaning head (10) further comprises a seal adjustment means (80), configured to move the seal assembly (39) with respect to the rotating brush (33) along the surface-facing direction.

Description

CLEANING HEAD FOR CLEANING AN UNDERWATER SURFACE

Technical Field

The present invention relates to a cleaning head suitable for cleaning surfaces below the water surface, such as boat hulls.

Background Art

US6877452B1 discloses a boat cleaning assembly with brushes. The brushes are arranged on respective arms and on a gimbal arrangement, such that they can adapt to the angle of the boat hull.

US5441368A presents a solution for removing fouling on submerged marine surfaces, wherein a cleaning member arranged on telescopic arms can be submerged for cleaning said surfaces.

DE19718974A1 shows a similar assembly, wherein a plurality of brushes are used to clean the hull of a boat below the water line.

US20080216732A1 uses a vast number of cleaning brushes to clean the submerged portion of a hull.

While several solutions for cleaning boat hulls are known, few solutions are designed for taking care of the substances that are removed from the hull. Such substances may contain hazardous waste that should be treated accordingly, instead of being let into the sea.

Furthermore, known solutions involve controlling the force against the boat hull by merely controlling the arm carrying the brush head. Consequently, some parts of the hull may experience excessive brush force, while other parts may experience too low brush force.

An object of the present invention may be to provide a cleaning head that is configured for collecting the substances that er cleaned off the cleaned surface.

Another object of the present invention may be to provide a cleaning head that enable a better controllable contact force against the cleaned surface. Summary of invention

According to a first aspect of the present invention, there is provided a cleaning head for cleaning an underwater surface, such as a boat hull. The cleaning head comprises a main housing comprising a front rim that defines a front aperture facing in a surface-facing direction, a seal assembly configured to abut the underwater surface, a rotating brush configured to abut the underwater surface, and a brush motor to rotate the rotating brush.

The position of the seal assembly with respect to the position of the rotating brush is adjustable along the surface-facing direction, as the cleaning head further comprises a seal adjustment means. The seal adjustment means is configured to move the seal assembly with respect to the rotating brush along the surface-facing direction.

With the term "surface-facing direction" is meant the direction towards the underwater surface when the cleaning head is in use.

Preferably, the seal assembly is arranged on the front rim of the main housing, protruding in the surface -facing direction. In this manner, when the main housing is moved against the hull, the seal assembly will abut against the hull and provide some sealing function against the hull.

In some embodiments, the seal adjustment means can comprise an inflatable bellows. In this manner, the mutual position between the seal assembly and the rotating brush can be governed by supply of fluid into and out of the inflatable bellows.

The cleaning head can have a brush plate, wherein the rotating brush protrudes from the brush plate with a circular configuration. Moreover, the cleaning head can further comprise a vane assembly within the circular configuration. The vane assembly can comprise a vane arranged on the brush plate. A vane aperture can extend through the brush plate, from the vane to the opposite side of the brush plate. The vane assembly will contribute in flowing water in the desired direction, as will be discussed further below. In some embodiments, the cleaning head can comprise a flow gap arranged radially outside the rotating brush and the brush plate. In such embodiments, the radial distance of the flow gap can correspond to at least 5 % of the radius of the rotating brush or at least 5 % of the radius of the brush plate.

In some embodiments, the radial distance of the gap can be even larger, for instance 10 % or 15 % of the radius of the rotating brush or brush plate, respectively.

The flow gap will thus be substantial, such that a substantial amount of water can flow on the radially outside of the rotating brush.

The vane assembly will provide a water flow through the brush plate. As a result, debris and particles removed from the underwater surface will be transported towards the center portion of the main body, away from the seal assembly. This will contribute to reducing the risk of possible leakage of removed contaminants from within the main housing and into the ambience, through the seal assembly. The water flow on the radial outside of the rotating brush will also contribute to reducing the risk of possible leakage, as water, with possibly suspended contaminants and debris, will flow towards the water outlet (i.e. away from the seal assembly).

The cleaning head may also comprise a base plate between the brush motor and the main housing, a drive shaft connecting the brush motor to the rotating brush, wherein the drive shaft extends into the main housing.

In such embodiments, the seal adjustment means can advantageously be arranged between the main housing and the brush motor.

The cleaning head may further comprise a position gauge measuring the mutual position between the rotating brush and the main housing. In this manner, the operator, or a control unit, can control the mutual position of the seal assembly and the rotating brush based on such input.

Advantageously, the cleaning head can further comprise a force gauge configured to measure a force between a cleaning rig, to which the cleaning head is attached, and the cleaning head.

In some embodiments, wherein the cleaning head comprises the gimbal assembly and the support assembly, the force gauge can advantageously measure the force between the support assembly and the gimbal assembly.

The force gauge can give information to the operator and/or a control unit about the force exerted from the cleaning rig onto the cleaning head, and hence onto the underwater surface.

In embodiments wherein the cleaning head comprises the linear actuator, the force gauge can be arranged between the linear actuator and the gimbal assembly. The force gauge can, however, instead be arranged such that the linear actuator is between the force gauge and the gimbal assembly.

The cleaning rig can be of various types, such as a robotic arm manipulating the cleaning head.

The seal assembly can advantageously comprise a brush seal. As will become apparent from the further discussion below, although the term seal is used herein, some intended flow of water shall occur. I.e., some water shall flow into the cleaning head, past the seal assembly, and will be let out through a water outlet.

The cleaning head may further comprise an auxiliary seal, wherein the seal assembly protrudes beyond the auxiliary seal in the surface-facing direction.

The auxiliary seal can protrude in the same, surface-facing direction as the seal assembly.

Preferably, the auxiliary seal can be arranged radially outside the seal assembly.

The inclusion of the auxiliary seal can reduce the amount of water that enters cleaning head. Consequently, the amount of water that has been used for the cleaning process will be less. In a typical embodiment, where the used and thus dirty water shall be treated in a water cleaning facility, this will result in less water that needs to be cleaned.

In some embodiments, the cleaning head comprises a gimbal assembly, and a support assembly that supports, with the gimbal assembly, the main body, the seal assembly, and the rotating brush. Further, it may comprise a linear actuator, wherein the position of the seal assembly and the position of the rotating brush, with respect to the support assembly, are controlled by the linear actuator.

With such a linear actuator, the operator and/or a control unit, can accurately adjust the position of the cleaning head with respect to the underwater surface that shall be cleaned. Le., the contact force between the cleaning head and the underwater surface can be controlled with improved accuracy.

In embodiments where the adjustment means is an inflatable bellows, the inflatable bellows can be in form of a tubular circle with two ends. This facilitates replacement of the bellows.

According to a second aspect of the present invention, there is provided a cleaning head for cleaning an underwater surface, such as a boat hull. The cleaning head comprises a main housing comprising a front rim that defines a front aperture facing in a surface-facing direction. Further, it comprises a seal assembly configured to abut against the underwater surface, and a brush assembly comprising a rotating brush. According to the second aspect of the invention, the cleaning head comprises a flow gap radially outside of the brush assembly, wherein the radial dimension of the flow gap is at least 15 mm, or wherein the radial dimension of the flow gap is at least 5 % of the radius of the brush assembly.

In some embodiments of this aspect of the invention, the radial dimension of the flow gap can be at least 20 mm, or at least 25 mm. Alternatively or in addition, the radial dimension of the flow gap can be at least 10 %, 15 % or even 20 % of the radius of the brush assembly.

The flow gap can typically be located between the brush assembly and an internal face of the main housing.

According to a third aspect of the present invention, there is provided a cleaning rig comprising a cleaning head according to one of the aspects presented above. The cleaning rig further comprises a control unit configured to control the rotational speed of the rotating brush and the seal adjustment means, based on input from one or more of

- a position gauge which is configured to measure mutual position between the brush and the main housing; - a force gauge configured to measure a force exerted onto the cleaning head from the cleaning rig;

- a hull inspection assembly;

- an impact detection arrangement;

- measured characteristics of outlet water exiting the cleaning head.

In one embodiment of the cleaning rig, the control unit is configured to control one or more of

- a pneumatic air supply that is connected to the seal adjustment means;

- the rotor motor;

- a linear actuator governing the position of the seal assembly and the position of the rotating brush, with respect to a support assembly;

- an adjustable outlet valve arranged inline with a water outlet, wherein the outlet valve is configured to control the outlet of water through the water outlet;

- a pump arranged in line with a water outer.

Detailed description of the invention

While various possible features of the invention have been discussed in general terms above, a more detailed and non-limiting example of embodiment will be presented in the following with reference to the drawings, in which

Fig. 1 depicts a hull cleaning assembly configured to clean the submerged portion of a boat hull while the boat is in the water;

Fig. 2 is a perspective view of a cleaning head;

Fig. 3a is a cross-section side view of the cleaning head shown in Fig. 2;

Fig. 3b is a cross-section side view of an upper part of an alternative embodiment of the cleaning head;

Fig. 4 is a side view of the cleaning head shown in Fig. 2;

Fig. 5 is another cross-section side view of the cleaning head shown in Fig. 2; Fig. 5a is a top view of a seal adjustment means in the form of a bellows;

Fig. 6 is a perspective view of an embodiment of the cleaning head;

Fig. 7a is a perspective view showing a portion of an embodiment of the cleaning head;

Fig. 7b is a perspective view of a carriage assembly that can be part of a cleaning head;

Fig. 8 is a cross-section side view of a portion of a cleaning head, illustrating water flowing into a cleaning head main housing;

Fig. 9 is a perspective view depicting a brush of the cleaning head; and

Fig. 10 is a schematic illustration depicting a control unit having possible interfaces.

Fig. 1 depicts a hull cleaning assembly 1 configured for cleaning the portion of a boat hull 3 that is below the water surface. The hull cleaning assembly 1 comprises two cleaning heads 10 that are carried on a cleaning rig 20. In the shown embodiment, the cleaning rig 20 is installed on a floating pier 5. The cleaning rig 20 comprises two towers 21 that supports two arms 23. The two cleaning heads 10 are supported on the respective arms 23. Furthermore, the said towers 21 are configured to move horizontally on horizontal guides 7 that are arranged on the floating pier 5. Advantageously, the cleaning head 10 is supported by a carrier that can move along the extension of the arm 23.

The arms 23 can move vertically on the towers 21 . Moreover, the cleaning heads 10 can move along the extension of the respective arms 23. As now will be understood, the cleaning heads 10 can thus be moved along the hull surface for cleaning the hull 3. Moreover, the brushes can be moved up and out above the water surface.

Other configurations of a cleaning rig 20 are possible, for instance including telescopic members, robot arms controlling the cleaning heads 10, assemblies comprising only one cleaning head 10, etc.

Reference is now made to Fig. 2 and to Fig. 3a. Fig. 2 is a perspective view of a cleaning head 10, while Fig. 3a shows the cleaning head 10 with a crosssection side view. The cleaning head 10 comprises a main housing 31 with a front aperture configured to face the boat hull 3. Inside the main housing 31 there is arranged a cleaning device, here in the form of a rotating brush 33. In some embodiments, the brush 33 may comprise fibers from plants, such as piassava. In such embodiments, the brush 33 will comprise a plurality of piassava fibers arranged to form a brush. As the skilled person will appreciate, the brush 33 is configured to clean the surface of a boat hull 3 when moved against the hull.

The brush 33 can also comprise synthetic brush wires.

Also shown in Fig. 3a, is a front rim 37 of the main housing 31 . The front rim 37 defines the said front aperture of the main housing 31 .

Protruding from the front rim 37 there is arranged a seal assembly 39. The seal assembly 39 protrudes towards the boat hull 3 during cleaning. Furthermore, the seal assembly 39 has a circular configuration such that it encircles the aperture of the main housing 31 . The aperture of the main housing 31 is defined by the front rim 37.

Preferably, the seal assembly 39 comprises a brush seal, as in the shown embodiment. Moreover, in the shown embodiment, the seal assembly 39 comprises a first brush seal 39a and a second brush seal 39b. Depending on embodiment, the first and second brush seals 39a, 39b may have different characteristics. Moreover, in some embodiments, there may be only one brush seal, or even more than two brush seals.

Furthermore, surrounding the front aperture of the main housing 31 , there is arranged an auxiliary seal 35. The auxiliary seal 35 has a circular configuration. It can be a flexible lip seal configured to protrude towards the boat hull 3, beyond the extension of the main housing 31 . Consequently, when or if the main housing 31 is forced against the boat hull 3, the auxiliary seal 35 may contact the boat hull 3 and provide some degree of sealing function between the interior of the main housing 31 and the ambience. While the auxiliary seal 35 is well shown in Fig. 2, its attachment to the main housing 31 appears also from the cross-section side view shown in Fig. 3a. The seal assembly 39 protrudes further than the auxiliary seal 35. Consequently, when moving the cleaning head 10 towards the boat hull 3, the seal assembly 39 will abut the boat hull 3 while the auxiliary seal 35 may not abut the boat hull 3. This will depend on the force used to press the cleaning head 10 against the boat hull 3. It may also partly depend on the configuration of the boat hull 3. For instance, if the boat hull 3 comprises sharp, protruding edges, as is common for planing boats, these may bend away the seal assembly 39 and possibly contact the auxiliary seal 35.

As will be discussed in better detail below, although the term “seal’ is used herein, the seal assembly 39 and the auxiliary seal 35 are configured to admit a flow of water into the interior of the main housing 31 . Le., during operation, an intended leakage of water will occur, past the seals and into the interior of the main housing 31 .

As illustrated in Fig. 2, in the shown embodiment the cleaning head 10 comprises a gimbal assembly 40, through which it is suspended to the cleaning rig 20. The gimbal assembly 40 comprises an attachment bow 41 . The attachment bow 41 connects to the cleaning rig 20 at its attachment portion 41 a.

A suspension element 43, which in the present embodiment is in the form of a suspension ring, connects to the attachment bow 41 over a pair of primary hinges 43a, of which only one primary hinge 43a is visible in Fig. 2. The primary hinges 43a are located at the respective ends of two primary suspension arms 43b that extends from the suspension ring 43. The suspension element 43 is thus able to pivot about a first pivot axis that extends between the two primary hinges 43a.

To the suspension element 43 there is attached a base element 45 (Fig. 3a). The base element 45 comprises a base plate 45a, from which two base arms 45b extends such as to configure the base element 45 as a bow. The base element 45 connects to the suspension element 43 over two secondary hinges 45c. The secondary hinges 45c are located at the respective base arms 45b and at two secondary suspension arms 43c. As the skilled person will appreciate, the suspension element 43 is able to pivot with respect to the base element 45, about a second axis that extends between the two secondary hinges 45c. Since the main housing 31 connects to the base element 45, as will be discussed further below, the main housing 31 is able to pivot about said first and second axes. Consequently, when the cleaning head 10 abuts the boat hull 3, it is configured to adapt its orientation to the boat hull.

Referring still to Fig. 2 and to Fig. 3a, at the rear of (or below with the orientation shown in these images) the main housing 31 , there is a motor housing 51 . The motor housing 51 is attached to the base plate 45a of the base element 45. The base plate 45a is thus interposed between the main housing 31 and the motor housing 51 , as shown in Fig. 3a.

Inside the motor housing 51 there is a brush motor 53 configured to rotate the rotating brush 33. The motor housing 51 has a releasable lid 51 a to provide access to the interior of the motor housing 51 . The brush motor 53 has a motor shaft 55 that connects to a through drive shaft 57. Furthermore, the through drive shaft 57 connects to a brush plate 59, to which said rotating brush 33 is attached. Hence, when the brush motor 53 is operated, the rotating brush 33 rotates.

The rotating brush 33 and the brush plate 59 are parts of a rotating brush assembly 30.

The brush motor 53 can be of various types. For instance, the brush motor 53 can be a pneumatic motor (air motor), a hydraulic motor or an electric motor. In the shown embodiment, the brush motor 53 is a pneumatic motor. The pneumatic motor 53 has an air supply inlet 53a and an air outlet 53b.

In the shown embodiment the interior of the motor housing 51 is sealed off from the ambient water. Consequently, the through drive shaft 57 extends through a rotary shaft seal 61 . Furthermore, a bearing 63 is arranged as an interface between the base plate 45a and the through drive shaft 57.

While the purpose of the rotary shaft seal 61 is to prevent water from entering the motor housing 51 , a further means for preventing such intrusion is arranged. The motor housing 51 comprises pre-tensioned check valve 65, through which the air from the air outlet 53b of the pneumatic motor 53 can escape from the motor housing 51 . The check valve 65 is adjusted or pre-tensioned in such way that the pressure inside the motor housing 51 is larger than the pressure of the surrounding water. Consequently, in this manner water is prevented from entering the motor housing 51 . As the skilled person will appreciate, the pressure of the ambient water and hence the needed pressure inside the motor housing 51 will depend on the water depth.

In an alternative embodiment, a tube or hose (not shown) can connect to the check valve 65 and extend to a level above the water surface. In this manner, the air exiting the air outlet 53b of the pneumatic motor 53 is communicated back up to the air ambience.

Alternatively, such a tube or hose can connect directly to the interior of the motor housing 51 , i.e. without the shown check valve 65.

In yet another embodiment, the cleaning head 10 can be without the shown motor housing 51 . In such embodiments, one would need a brush motor 53 that tolerates use in water.

During cleaning of the boat hull 3, the brush 33 is pressed against the boat hull 3 while rotated with the brush motor 53. Due to the rotation of the brush 33, the water inside the main housing 31 takes a circulating flow pattern. Moreover, the rotating brush assembly 30 comprises one or more vane assemblies 70. In the shown embodiment, the vane assembly 70 comprises a vane 71 protruding upwards from the brush plate 59, and a vane aperture 73, which extends through the brush plate 59. As indicated with the dashed lines in Fig. 3a, the vane aperture 73 is arranged immediately below the vane 71 . During rotation of the brush plate 59, the vanes 71 collect water and cleaned-off debris, and force the water along with contamination down through the vane apertures 73. The water thus flows downwards, with respect to the orientation shown in Fig. 3a, towards the lower end of the main housing 31 .

As shown in Fig. 2 and Fig. 4, there is arranged a water outlet 32. During cleaning, water will enter the main housing 31 through gaps between the seal assembly 39 and the boat hull 3, and/or through the fibers of the first and second brush seals 39a, 39b. This forms a water inlet 34, which is indicated in Fig. 3a and which is better illustrated in Fig. 8.

As will be appreciated, the entering water will also flow through the gap between the auxiliary seal 35 and the boat hull 3. The entered water will be present inside the main housing 31 for some time during cleaning and will eventually flow out of the main housing 31 through the water outlet 32. The water exiting the main housing 31 may carry debris that is cleaned off the boat hull 3, such as marine fouling and antifouling paint (polymers) with biocides, as well as wear and tear from the brush 33.

As is perhaps best shown with the perspective view of Fig. 9, the rotating brush 33 circular shape, protruding up from the brush plate 59. Moreover, the vanes 71 are arranged inside the circular shape of the rotating brush 33.

Consequently, debris and other contents that are cleaned off the boat hull 3, will be transported with the water flow within said circular shape and through the vane assembly 70.

The amount of water entering the main housing 31 can primarily be adjusted by controlling the water flow through the water outlet 32. Such control can for instance be provided with a manually or automatically operated outlet valve 121 , which is schematically shown in Fig. 10, being controlled by a control unit 110. Typically, an outlet hose will be connected the water outlet 32. The outlet valve 121 can be connected in line with the outlet hose above the water surface. Moreover, a pump 123, which is schematically shown as being controlled by the control unit 110 in Fig. 10, can be connected to the water outlet 32. Such a pump 123 can typically be arranged below the water surface.

Since the water flowing out of the water outlet 32 will or may contain contaminants, it is advantageous to use a low flow of water out from the water outlet. That will result in less amount of water that shall be cleaned.

As an auxiliary means of controlling the water flow into the main housing 31 , the operator can adjust the force by which the seal assembly 39 if pressed against the boat hull 3. As the skilled person will appreciate, if forcing the seal assembly 39, along with the auxiliary seal 35, against the boat hull 3 with increased force, less water may enter the main housing 31 . The desired amount of water flowing into (and thus out of) the main housing 31 may be affected by the amount of matter (dirt, fouling, etc.) that is cleaned off the boat hull 3, the composition of such matter, and the ability to receive the contaminated water for treatment. The water exiting through the water outlet 32 can be transported to a water holding tank (not shown). A transport pump (not shown) can be provided for pumping the used or contaminated water to the water holding tank.

The skilled person will now appreciate that during cleaning of the hull, both the main housing 31 with its seal assembly 39, and the rotating brush 33, will be pressed against the boat hull 3. The respective forces, by which the seal assembly 39 and the rotating brush 33 are pressed against the hull 3 may depend on the characteristics of the hull. In one embodiment, the operator may for instance want to press the seal assembly 39 against the hull 3 with a force corresponding to 2 kg (i.e. about 20 N), while the force from the rotating brush could correspond to 8 kg (i.e. about 80 N).

To provide such forces from the cleaning head 10 against the hull 3, a force must be applied from the cleaning rig 20, such as from the arm 23 shown in Fig. 1 , onto the cleaning hull 10.

Furthermore, due to the circulating water inside the main housing 31 , there will be a negative pressure inside the main housing (vortex effect). In addition, if water is pumped out from the water outlet 32, as discussed above, the pressure inside the main housing 31 may be even further reduced. Consequently, the hydrostatic pressure existing outside the main housing 31 will also contribute to forcing the main housing 31 , i.e. the seal assembly 39, against the boat hull 3.

To enable the operator to adjust the force from the seal assembly 39 onto the boat hull 3, the cleaning head 10 comprises a seal adjustment means 80. In Fig. 3a, interposed between the main housing 31 and the base plate 45a, the seal adjustment means 80 is shown. In the discussed embodiment, the seal adjustment means 80 is in the form of an inflatable bellows. Its function will be discussed in the following with particular reference to Fig. 3a, Fig. 4, and Fig. 5. In other embodiments, the seal adjustment means 80 may have other configurations, for instance hydraulic members, electric actuators, etc.

Fig. 4 depicts the cleaning head 10 with a side view, with some parts removed for illustrative purpose. The bellows 80 is configured as an endless ring, like the inner tube of an inflatable wheel. The bellows 80 encircles the drive shaft 57.

Fig. 5 is a cross-section side view corresponding to Fig. 3a. However, as appears from Fig. 5, the bellows 80 has been somewhat compressed. This compression is due to the force onto the main housing 31 , i.e. onto the seal assembly 39, from the boat hull 3.

While the position of the brush 33 with respect to the base plate 45a, along the axial direction of the drive shaft 57, remains constant, the axial position of the main housing 31 does not. Instead, due to the force onto the main housing 31 , the bellows 80 has become compressed such that the axial position of the main housing 31 is closer to the base plate 45a. As a result, the rotating brush 33 will be pressed against the boat hull 3 with increased force, while less force appears between the seal assembly 39 and the boat hull 3.

The fluid, (e.g. a gas, typically air) pressure inside the bellows 80 can be controlled through an air supply line 81 , which in Fig. 3a is merely schematically illustrated. The air supply line 81 is connected to an air supply (not shown) and a control system (not shown) for controlling the pressure inside the bellows 80. The air supply can provide pressurized air to the bellows 80. Hence, if the operator, or possibly a control system, needs to adjust the force applied from the main housing 31 (i.e. the seal assembly 39) against the hull 3, the pressure in the bellows 80 is altered. For instance, if more pressure shall be applied from the seal assembly 39 against the boat hull 3, the gas pressure inside the bellows 80 is increased.

As schematically shown in Fig. 3a and Fig. 5, there is arranged a position gauge 83 which is configured to measure mutual position between the brush 33 and the main housing 31 . In the shown embodiment, the position gauge 83 is arranged between the base plate 45a and the main housing 31 .

Also shown in Fig. 3a and Fig. 5 are a plurality of bellows protection elements 85, which limit the maximum compression of the bellows 80.

The main housing 31 thus slides along the drive shaft 57, when the bellows is operated or compressed. To maintain a constant angular position between the main housing 31 and the base plate 45, motor housing 51 etc., a rotation preventer arrangement can be arranged (not shown). Such a rotation preventer arrangement can for instance be a protrusion extending from the main housing 31 into a receiving slot arranged on the base plate 45a. Fig. 5a depicts an alternative embodiment of the seal adjustment means 80, wherein the bellows 80 does not have the shape of an endless ring. Instead, the bellows 80 shown in Fig. 5a has the shape of a tubular circle with two ends 80a. In this manner, the operator can replace the bellows 80 easier, since drive shaft 57 can be received between the two ends 80a such that the bellows can be put into its operating position. Le., the bellows 80 can be put into its operating position with a movement directed radially with respect to the drive shaft 57.

Fig. 6 is a perspective view showing an embodiment of the cleaning head 10, wherein the cleaning head comprises a support assembly 400. Reference is also made to Fig. 7b, which depicts the support assembly 400 from another angle and with several parts of the cleaning head 10 removed for illustrational purpose.

In the shown embodiment, the support assembly 400 is in form of a carriage, provided with wheels 401 for moving along the arm 23 of the cleaning rig 20. The main body 31 , the attachment bow 41 , and the suspension element 43 discussed above can be recognized in Fig. 6.

The support assembly 400 comprises a linear guide 403 which is shown in Fig. 7b. The linear guide 403 is configured to receive a guide element 405, which is shown in Fig. 2. The shown embodiment comprises two guide elements 405, of which one is configured to be guided in a linear direction by two linear guides 403. The guide elements 405 are arranged on the attachment bow 41 .

Shown in Fig. 6 is a linear actuator 407. In the shown embodiment, the linear actuator 407 is in form a telescopic drive. It may for instance be an electrically, pneumatically, or hydraulically driven actuator. The linear actuator 407 is at one end attached to an actuator plate 409, which is fixed with respect to the support assembly 400. At its opposite end, the linear actuator 407 is attached to the attachment portion 41 a (see Fig. 2) of the attachment bow 41 .

As the skilled reader now will appreciate, by operating the linear actuator 407, the vertical position of the brush 33 can be adjusted. It shall be appreciated that in this context, the term vertical is used with respect to for instance the image shown in Fig. 2. During use, the cleaning head 10 may of course have a different orientation, depending on the hull 3 being cleaned. When operating the linear actuator 407, the guide elements 405 will move along the linear guides 403.

By operating the linear actuator 407, both the main body 31 (on which inter alia the seal assembly 39 is arranged) and the rotating brush 33 can be moved. In addition, and as discussed above, the operator can control the mutual position between the main body 31 and the rotating brush 33.

While some types of cleaning rigs may be capable of controlling the position of the cleaning head 10 with sufficient accuracy and speed, other cleaning rigs may not. In the latter cases, the linear actuator 407 will enable the operator, or typically a control unit, to control the position of the cleaning head 10 with respect to the boat hull 3 with better precision and speed. In other embodiments the cleaning head 10 can be manipulated with an arrangement configured to control the position and the applied force between the cleaning head 10 and the boat hull, such that the linear actuator 407 would be superfluous. Such an arrangement could for instance be a robotic arm (not shown).

Referring again to Fig. 7b, the support assembly 400 comprises a transversal beam element with an actuator aperture 411 , through which the linear actuator 407 will extend.

It will be understood that while the support assembly 400 discussed above is in form of a carriage with wheels 401 , other embodiments may be different. For instance, the support assembly 400 may be an assembly without wheels, for instance being manipulated at the end portion of a robotic arm (not shown).

Reference is now made to Fig. 3b, which illustrates an upper portion of the cleaning head 10 with a cross-section side view. In this embodiment, the cleaning head 10 comprises an impact detection arrangement 200. The impact detection arrangement 200 is configured to detect a collision between the cleaning head 10 and an object. Typically, the impact detection arrangement 200 will detect a collision between the cleaning head 10 and an object during lateral movement of the cleaning head 10 along the surface of the boat hull 3. A control unit that controls the movement of the cleaning head 10 can be configured to stop the movement or alter the movement of the cleaning head 10 upon detection of such a collision. In the embodiment shown in Fig. 3b, the impact detection arrangement 200 comprises an impact bow 201 that is attached to the main housing 31 with a plurality of attachment means 203. In the embodiment shown in fig. 3b, the impact bow 201 is in form of a ring element that encircles the main body 31 and that is arranged with a distance from the main body 31 . The impact detection can be provided in various manners. For instance, the impact bow 201 may be of a soft material and may comprise an inner tube filled with a monitored gas pressure. Thus, an impact will compress the inner tube and trigger a rise in the monitored gas pressure.

Fig. 7a is a perspective view showing the attachment bow 41 and the attachment portion 41 a, which is part of the attachment bow 41 . To measure the force by which the entire cleaning head is pressed against the boat hull 3, there is arranged a force gauge 90 between the attachment bow 41 and the linear actuator 407 (not shown in Fig. 7a). Thus, the operator or a control unit can monitor this applied force against the hull 3. The force gauge 90 may typically comprise a compression load cell, by means of which the force can be monitored. It will be understood that the total force exerted from the cleaning head 10 onto the boat hull 3, is distributed between the force from the rotating brush 33 and the force from the seal assembly 39. Moreover, this force distribution can be controlled with the seal adjustment means 80.

Fig. 7a further shows an embodiment where the cleaning head 10 comprises a hull inspection assembly 100. The hull inspection assembly 100 can comprise a data capturing device 101 , which in the shown image is in form of a camera 101 configured to monitor the boat hull 3, typically when the cleaning head 10 abuts against and moves along the boat hull 3. In the shown embodiment, the hull inspection assembly 100 comprises an inspection support arm 103, on which the camera 101 is supported.

Fig. 7b depicts an alternative embodiment of the hull inspection assembly 100. In this embodiment, the hull inspection assembly 100 is connected to the support assembly 400 discussed above.

The hull inspection assembly 100 can be used for various types of data capturing. The captured data can be used as basis for control of the various functions of the cleaning head 10, and for movement of the cleaning head along the hull 3. The data capturing device 101 , can for instance be a submergible stereo camera, a green laser apparatus, an ultrasound device, or similar.

Typical data capturing can include 3D scan of the hull (below the waterline), wherein the shape of the hull’s surface is scanned, as well as the components of the surface (e.g. chemicals, types of fouling, hull damages etc.). Furthermore, the data capturing can include real-time monitoring of the position of the cleaning head 10 with respect to the hull 3 during cleaning.

Fig. 8 shows a cross-section side-view through a portion of the cleaning head 10 during cleaning of a boat hull 3. A water inlet 34 is indicated at the interface between the boat hull 3 and the seal assembly 39. As indicated with the dashed arrows, some water may enter the main housing 31 through a gap between the seal assembly 39 and the boat hull 3. Furthermore, some water may enter through the seal assembly 39 itself, i.e. through the first and second brush seals 39a, 39b in the present embodiment.

Fig. 9 is a perspective view illustrating the embodiment of the vane assembly 70 in better detail. As shown in this image, the vane 71 extends upward from the brush plate 59. When the brush plate 59 rotates, clockwise in the shown embodiment, water will be collected by the vane 71 and transported to the opposite side of the brush plate 59, through the vane aperture 73.

Fig. 10 is a schematic diagram showing a control unit 110 configured to control various functions of the cleaning head 10. Moreover, it is configured to control such functions based on input from various input devices, such as the position gauge 83, the force gauge 90, the hull inspection assembly 100, and the impact detection arrangement 200. Among the functions or devices, which the control unit 110 can be configured to control, are the brush motor 53, the seal adjustment means 80 (bellows), the linear actuator 407, the outlet valve 121 , and the pump 123. In the shown embodiment, a schematically shown pneumatic air supply 111 is configured to supply pressurized air to the rotor motor 53. Thus, by controlling the air supply 111 with the control unit 110, the speed of the rotating brush 33 is controlled.

Furthermore, by controlling, with the control unit 110 via the air supply 111 , the pressure inside the bellows 80, the mutual axial position between the rotating brush 33 and the seal assembly 39 can be controlled.

Monitored parameters that may affect the control of the speed of the rotating brush 33 and the seal adjustment means, i.e. the bellows 80, can typically comprise:

- the force measured by the force gauge 90;

- the mutual position between the brush 33 and the main housing 31 , as measured by the position gauge 83;

- input from the hull inspection assembly 100, which may be interpreted by the control unit 110 or other means, which may provide input about the shape of the boat hull 3, and/or about its condition, such as degree of fouling etc.

Also connected to the control unit 110 is a cleaning unit movement control line 113. The cleaning unit movement control line 113 can be used to control the movement of the cleaning unit 10, such as its speed along the boat hull 3 and the total force between the cleaning unit 10 and the boat hull 3, as measured (at least indirectly) by the force gauge 90.

Claims

1 . A cleaning head (10) for cleaning an underwater surface (3), such as a boat hull, comprising

- a main housing (31 ) comprising a front rim (37) that defines a front aperture facing in a surface-facing direction;

- a seal assembly (39) configured to abut the underwater surface (3);

- a rotating brush (33) configured to abut the underwater surface (3);

- a brush motor (53) to rotate the rotating brush (33); characterized in that the position of the seal assembly (39) with respect to the position of the rotating brush (33) is adjustable along the surface-facing direction, as the cleaning head (10) further comprises a seal adjustment means (80), configured to move the seal assembly (39) with respect to the rotating brush (33) along the surface-facing direction.

2. A cleaning head (10) according to claim 1 , characterized in that the seal adjustment means (80) comprises an inflatable bellows.

3. A cleaning head (10) according to one of the preceding claims, characterized in that it comprises a brush plate (59), wherein the rotating brush (33) protrudes from the brush plate with a circular configuration, and wherein the cleaning head further comprises a vane assembly (70) within the circular configuration, as the vane assembly (70) comprises

- a vane (71 ) arranged on the brush plate (59);

- a vane aperture (73) extending through the brush plate (59), from the vane (71 ) to the opposite side of the brush plate.

4. A cleaning head according to claim 3, characterized in that it comprises a flow gap (33a, 59a) arranged radially outside the rotating brush (33) and the brush plate (59), wherein the radial distance of the flow gap (33a, 59a) corresponds to at least 5 % of the radius of the rotating brush (33) or at least 5 % of the radius of the brush plate (59).

5. A cleaning head (10) according to one of the preceding claims, characterized in that it further comprises

- a base plate (45a) between the brush motor (53) and the main housing (31 );

- a drive shaft (57) connecting the brush motor (53) to the rotating brush (33), wherein the drive shaft (57) extends into the main housing (31 ).

6. A cleaning head (10) according to claim 5, characterized in that the seal adjustment means (80) is arranged between the main housing (31 ) and the brush motor (53).

7. A cleaning head (10) according to any one of the preceding claims, characterized in that it further comprises a position gauge (83) measuring the mutual position between the rotating brush (33) and the main housing (31 ).

8. A cleaning head (10) according to one of the preceding claims, characterized in that it further comprises a force gauge (90) configured to measure a force between a cleaning rig (20), to which the cleaning head (10) is attached, and the cleaning head (10).

9. A cleaning head (10) according to one of the preceding claims, characterized in that the seal assembly (39) comprises a brush seal.

10. A cleaning head (10) according to one of the preceding claims, characterized in that it further comprises an auxiliary seal (35), wherein the seal assembly (39) protrudes beyond the auxiliary seal (35) in the surfacefacing direction.

1 1 . A cleaning head (10) according to one of the preceding claims, characterized in that it further comprises

- a gimbal assembly (40);

- a support assembly (400) supporting, with the gimbal assembly (40), the main body (31 ), the seal assembly (39), and the rotating brush (33);

- a linear actuator (407), wherein the position of the seal assembly (39) and the position of the rotating brush (33), with respect to the support assembly (400), are controlled by the linear actuator (407).

12. A cleaning head (10) according to claim 2, or according to claim 2 and any other preceding claim, characterized in that the inflatable bellows (80) is in form of a tubular circle with two ends (80a).

13. A cleaning head (10) for cleaning an underwater surface (3), such as a boat hull, comprising

- a seal assembly (39) configured to abut against the underwater surface (3);

- a brush assembly (30) comprising a rotating brush (33), characterized in that it comprises a flow gap (33a, 59a) radially outside of the brush assembly (30), wherein the radial dimension of the flow gap is at least 15 mm, or wherein the radial dimension of the flow gap is at least 5 % of the radius of the brush assembly (30).

14. A cleaning rig (20) comprising a cleaning head (10) according to one of the preceding claims, wherein the cleaning rig (20) further comprises a control unit (110) configured to control the rotational speed of the rotating brush (33) and the seal adjustment means (80), based on input from one or more of

- a position gauge (83) which is configured to measure mutual position between the brush (33) and the main housing (31 );

- a force gauge (90) configured to measure a force exerted onto the cleaning head (10) from the cleaning rig (20);

- a hull inspection assembly (100);

- an impact detection arrangement (200);

- measured characteristics of outlet water exiting the cleaning head.

15. A cleaning rig (10) according to claim 14, characterized in that the control unit (110) is configured to control one or more of

- a pneumatic air supply (111 ) that is connected to the seal adjustment means (80);

- the rotor motor (53);

- a linear actuator (407) governing the position of the seal assembly (39) and the position of the rotating brush (33), with respect to a support assembly (400);

- an adjustable outlet valve (121 ) arranged inline with a water outlet (32), wherein the outlet valve (121 ) is configured to control the outlet of water through the water outlet (32);

- a pump (123) arranged in line with a water outer (32).