This invention relates to a cleaning apparatus. Specifically, it involves a cleaning apparatus for cleaning undesired material from the surface of an object, wherein a rotor which is rotatable about an axis, comprises at least one outwardly extending cleaning element, said cleaning element by rotation of the rotor about the axis is arranged to repeatedly impact against the surface of the object.

During various operations such as assembly, maintenance or disassembly of submerged objects, it is often necessary to clean at least parts of the surface of the object. Typical surface contaminants are marine fouling, shells, mineral deposits, corrosion products, mud and gravel.

It is known to use rotary cleaning tools where metallic cleaning elements may, for example, in the form of chain or metal rods/wires repeatedly impact against the surface of the object to be cleaned. Cleaning tools of this nature can be effective, but often damage the surface of the object.

From publication US3616484 is known a sleeve body which encloses a portion of a rotating end brush. The sleeve body may be made of a plastic material.

From publication US4200947 is known a rotary cleaning device comprising a boss which is provided with projecting brush elements which are preferably steel rods having a minimal degree of flexibility. One of the purposes of the cleaning device is to remove paint from a surface.

From publication WO8100689 is known a grinding tool in which a number of steel rods project from a core. The steel rods are arranged such that they can be removed from the tool in a simple way.

It is also known to use sharp cleaning elements, which may have the same disadvantages as mentioned above. In some cases, brush-like cleaning elements made of thin fibers of synthetic or natural materials are used. Tampico fiber is an example of a natural material which is used in a brush-like cleaning element. Such brush-like synthetic or natural materials generally show a relatively poor efficiency when used against adhering contaminants or loose contaminants with relatively high density, such as gravel, both of which can be removed using the present invention. Said contaminants having a relatively high density may for example cover a portion of a pipe on the seabed.

Cleaning using high pressure water is effective at shallow water depth, but the clea ning action decreases with depth because the pressure difference between the water pressure and the ambient pressure decreases.

The invention has for its object to remedy or reduce at least one of the disadvantages of the prior art.

This object is achieved according to the invention by the features defined in the following description and in the appended claims.

The invention is defined by the independent patent claims. The dependent claims define advantageous embodiments of the invention.

There is provided a cleaning apparatus for cleaning undesired material from the surface of an object, wherein a rotor which is rotatable about an axis, comprises at least one outwardly extending cleaning element, said cleaning element by rotation of the rotor about the axis is arranged to repeatedly impact against the surface of the object, and wherein the cleaning element comprises an elastomeric material having a density between 0.8 and 2.

Thus, an elastomeric material having a density between 0.8 and 2 is utilized in a cleaning element extending from a rotating apparatus.

The elastomeric material may be a natural or a synthetic material. Suitable materials which may be used in the cleaning element include, but are not limited to:

- Thermoplastic elastomers (TPE) such as styrene-copolyester, polyurethane, polyam- ide and polyolefin plastics;

- Natural rubber or synthetic rubber. An example of synthetic rubber which is suitable for the purpose is ethylene-propylene rubber (EPM). Cleaning elements of this nature have proven to be both effective and relatively gentle for cleaning underwater. They are insignificantly affected by the prevailing water pressure and show efficiency, also at greater depths. They are also suitable for use in air.

Practical tests show that amongst others, the TPE material polyurethane is suited for the purpose. Commercially available qualities of this material may be found with densities between 1 and 1.25.

The hardness of the cleaning element affects cleaning performance. Cleaning elements with a hardness of Shore 30A - 100A have been shown to be suitable to achieve the purpose of the invention.

Cleaning element elongation at break has through trials, been shown to be important for the lifetime and cleaning performance of the cleaning element. Elongation at break should be in the range 100% to 600%, and preferably closer to 600% than 100%. Previously named ethylene-propylene rubber (EPM) is an example of a material having an elongation of 600%.

In certain usage situations, it may be advantageous if the material of the cleaning element, in addition to the elastomeric material, comprises a proportion of polymeric constituents having physical characteristics that are different from the cleaning element's overall physical properties.

In this document, the overall physical properties refers to the physical properties that the cleaning element possesses during use. In some cases, also ceramic or metallic constituents may be included in the material of the cleaning element. The purpose of including particles of various constituents in the cleaning element is for example to increase the stiffness or average density of the cleaning element.

The previously mentioned polymeric, ceramic and metal constituents can be included in the cleaning element separately, or in any combination with the elastomeric material. Thus, the density of the cleaning element could be higher than 2.

In cases where it is desirable to maintain cleaning element gentle action against the surface of the object, it is advantageous if, for example, said polymeric, ceramic or metallic constituents are encapsulated in the cleaning member.

In use, the cleaning elements are subject to wear. Thus, any added polymeric, ceramic and/or metallic constituents may eventually be exposed to the surface of the object to be cleaned. To keep said added constituents entrapped in the elastomeric material for the greatest possible extent, the constituents may be disposed near a center portion of a longitudinal axis of the cleaning element, or to the side of the longitudinal axis which upon rotation of the cleaning element does not impact the surface of the object to be cleaned .

In some cases, it may be desirable that the cleaning element has a certain abrasive effect on the surface of the object to be cleaned . One such case would be where it is necessary to remove for example corrosion product or paint. In such a case, it may be advantageous if for example said ceramic, metallic and/or polymeric constituents are substantially uniformly distributed over the cleaning element cross section.

This has the effect that said constituents impact the surface of the object, also for a cleaning element that has not been reduced in cross section because of wear.

Trials have shown that up to 50% of cleaning element volume may comprise one or a combination of said polymeric, ceramic or metallic constituents.

In one embodiment, the previously mentioned polymeric, ceramic and/or metallic constituents are uniformly distributed along a longitudinal axis of the cleaning element.

In an alternative embodiment, the previously mentioned polymeric, ceramic and/or metallic constituents are non uniformly distributed along the longitudinal axis of the cleaning element.

For example, the previously mentioned polymeric, ceramic and/or metallic constituents can be applied only to a section along the cleaning element longitudinal axis so that the cleaning element density varies along the cleaning element longitudinal axis, for example, but not exclusively, closer to a free end portion of the cleaning element than the end portion of the cleaning element attachment to the rotor. It can thus provide a cleaning element which has a varying cleaning effect along its longitudinal axis. For example, by placing said polymeric, ceramic and/or metallic constituents in the end portion of the cleaning element, the cleaning element could cause a more powerful cleaning at one portion of the surface of the object than other portions of the surface of the object. Such a "variable" cleaning effect will be particularly useful if it is necessary to remove paint or rust on for example a weld in conjunction with NDT (non destructive testing), while the rest of the surface of the object requires only a gentle cleaning that does not harm the paint. In order to reduce the density of the cleaning in relation to the density of the elasto- meric material, a weight-reducing constituent can be introduced under manufacture of the cleaning element.

An example of a suitable weight-reducing constituent is a gas, for example air or nitrogen. Another example of a suitable weight-reducing constituent is small glass spheres, for example of the type sold under the trade name Q-Cel.

The cleaning element may be articulated attached to the rotor. Alternatively, the cleaning element may be screwed or otherwise coupled to the rotor by means of a fixed connection. In still another alternative embodiment, the cleaning element could be made in one piece, wherein the at least one outwardly extending cleaning element is fixed to a core or root portion connected to a rotor connected to a motor.

The cleaning apparatus is relatively gentle when cleaning painted surfaces, plastics, rubber and the like. Cleaning elements which do not include abrasive constituents such as the aforementioned ceramic or metallic constituents or where these are a rranged non-homogeneously in a cross section of the cleaning member as discussed above, is particularly gentle.

The cleaning apparatus motor, which is typically electrically, hydraulically or pneumatically driven, may advantageously be located near the rotor. The motor can if desired be mounted in the rotor.

The cleaning apparatus according to the invention can be configured with various attachments, for example to the object to be cleaned, a nearby structure, or an ROV.

However, it should be understood that the cleaning apparatus according to the invention could also be configured to be handled by an operator, such as a diver, carrying out cleaning in relatively shallow water. The previously mentioned attachment may thus be suitable handles.

The cleaning apparatus according to the invention enables effective and gentle cleaning also in deep water. The cleaning apparatus is also suitable for use in air and to remove material covering for example a buried pipe on the seabed.

The invention is defined by the independent patent claims. The dependent claims define advantageous embodiments of the invention.

In the following is described an example of a preferred embodiment illustrated in the accompanying drawings, wherein : Fig. 1 is a perspective view of a cleaning apparatus according to the invention; and

Fig. 2 shows an alternative embodiment of cleaning elements which are suitable for use in the cleaning apparatus.

Same or corresponding elements may be indicated by the same reference numerals in Fig. 1 and Fig. 2.

In Fig. 1 the numeral 1 denotes a cleaning apparatus comprising a central rotor 2 which is rotatable about an axis 4 and where the rotor 2 is provided with outward projecting cleaning elements 6.

A number of cleaning elements 6 are distributed in sets of three around the rotor 2. Each set of cleaning elements 6 is in the aforementioned figure connected to the rotor 2 by means of an articulated shaft 8. It should be understood that there can be more or fewer than the four cleaning elements 6 as shown.

Regardless of the number of cleaning elements 6, it is advantageous if the cleaning elements 6 are spaced substantially equidistant around the rotor 2 so that imbalance is avoided. By using two or more sets of cleaning elements 6, as shown in Fig. 1 and 2, where three sets are shown, the total number of cleaning elements 6 should be arranged balanced around the rotor 2.

This means that each individual set does not necessarily need to be balanced, as long as the total number of cleaning elements 6 are balanced

The rotor 2 with the cleaning elements 6 are connected to a motor 10, which is secured by means of a not shown attachment. The rotor 2 and the motor 10 is only shown in Fig. 1.

In Fig. 2 are also three sets of cleaning elements 6 arranged around the rotor (not shown). Unlike the cleaning elements 6 shown in Fig. 1, the four cleaning elements 6 in each of the sets in Fig. 2 are arranged integrated with a root portion 7 which is in engagement with the rotor in the position of use.

The engagement may for instance be provided by means of a not shown spline coupling. The root portion 7 and the cleaning elements 6 shown in Fig. 2 is molded in one piece.

In Fig. 2 the three sets of cleaning elements 6 and the corresponding root portion 7 are restrained against axial movement along the longitudinal axis 4 by means of a locking plate 9 which is brought into engagement with an end piece 7' by means of a screw/nut connection 9' .

The screw in the screw/nut connection 9' is threadedly connected with a motor not shown, for example of the type shown in Fig. 1. The end piece 7' may be made of the same elastomeric material as the root portion 7 and the cleaning elements 6.

In one embodiment, the end piece 7', the root portion 7 and the cleaning elements 6 are molded in one piece. In an alternative embodiment, end piece 7' may be fabricated separately from the root portion 7 and the cleaning elements 6.

In said alternative embodiment, the end piece 7' be made of the same elastomeric material as the root portion 7 and the cleaning elements 6, or they can be manufactured in another suitable material.

In order to arrange the sets of cleaning elements 6 with an axial clearance, the end- pieces are also arranged between each of the sets of cleaning elements 6.

By using separate end pieces 7', i.e. end pieces 7' which are fabricated separately from the root portion 7 and the cleaning elements 6, the mutual axial clearance between the sets of cleaning elements 6 is very easily adapted to the application .

For example, it would be desirable to have a small distance, typically 0.5-2 cm between the cleaning elements 6, if the purpose is to remove loose contamination from, for example, a pipeline on the seabed.

By simultaneously providing each of the sets of cleaning elements 6 side by side in the same plane as shown in Fig. 2, and thus not mutually angularly displaced about longitudinal axis 4, the cleaning elements provide a "shovel effect" and thus effectively remove soils from for example the previously mentioned pipeline.

Due to the individually movable cleaning elements 6, "the shovel" will also be effective in depressions or protruding portions on the surface of the object to be cleaned.

If the purpose of the cleaning is primarily to dislodge contaminants from the surface of an object 12, as the case will often be for objects present in water above the seabed, it may be advantageous to mount the cleaning elements 6 with larger mutual distance so that dislodged contaminants also can pass between two adjacent cleaning elements It should be noted that a combination of integrated end piece 7 ', that are molded integrally with the root portion 7 and the cleaning elements 6, and a separate end piece 7' to achieve the desired spacing between each set of cleaning elements 6 may also be used.

Depending on the type of contaminant to be removed from the surface of an object 12 the selection of suitable characteristics of the cleaning elements 6 can be made dependent upon density, hardness, elasticity and dimensions.

Cleaning elements 6 shown in Fig. 1 and Fig 2 has a uniform cross sectional shape along its longitudinal axis. In an alternative embodiment (not shown), one or more portions of the cleaning elements may be designed with varying cross section .

For example, a portion of the cleaning element 6 located adjacent to the free end portion of the cleaning element 6, may have a larger cross section than a portion located closer to said root portion 7 or the rotor 2.

Thus, one can obtain a similar effect to that obtained by placing said previously mentioned polymeric, ceramic and/or metallic constituents non-homogeneously along the cleaning element longitudinal axis.

The cleaning element 6 surface which impacts the surface of the object 12 to be cleaned, is in the embodiment of Fig. 1 and Fig. 2 shown with a smooth surface. However, it should be understood that at least a portion of said surface may possess an uneven surface, for example in the form of a surface undulating in an axial direction.

Such an undulating surface will exhibit greater friction when impacting the surface of the object 12 than a corresponding cleaning element 6 with a smooth surface.

During rotation of the cleaning apparatus 1, the cleaning elements 6 will impact against the surface of the object 12 to be cleaned.

The density, hardness, elasticity, dimension and rotation speed of the cleaning elements 6 can be chosen to provide an effective, yet gentle cleaning of the surface of the object 12 without damaging it in any appreciable degree.

In a prototype of the apparatus 1 the cleaning elements 6 are made of the TPE material polyurethane, and have a length of 250 mm and a square cross section measuring 25x25 mm. It should be understood that the cleaning elements 6 could be made of other suitable material and other dimensions that are tailored for specific applications. It should be noted that the above embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims.

In the claims, any reference numbers placed between parentheses shall not be con- strued as limiting the claim. Use of the verb "comprise" and its conjugations, does not exclude the presence of elements or steps other than those stated in a claim. The indefinite articles "a" or "an" in front of an element does not exclude the presence of a plurality of such elements.