Background Elements which are lying in water, will be fouled with marine organisms. This is a dis- advantage, because the organisms corrode the materials construction the elements, and, in addition, if the fouling is not equally distributed on the surface, it can cause imbalance.

Several solutions to this problem, i. e. removal of subsea fouling, are known, for example from US patent publications 5,001,801,5,069,234,5,085,016,5,265,634 and 5,615,696. All these devices are large, complex and heavy. When there is a need for cleaning light weight elements in water, it is impossible to use heavy devices, because this will influence the balance, and the element may overturn. Also, if fish are close by, which should not be affected of this cleaning, which for example is the case of a fish rearing unit, the construction should not be too large or noisy.

Object The main object of the invention is to provide a device for cleaning light weight constructions in water, the device shall be light, simple to use, for example from a boat, and not noisy.

In addition it should be easy to handle, either by the operator walking on the floating construction or from a boat or raft.

Invention The object of the invention is achieved by a device according to the characterizing part of patent claim 1. With this embodiment, it is possible for one person to clean fouled floating rings, without substantial effort. The device may be simple and robust and can be used with minor services. Wear will be limited to the brushes which can be replaced quickly and with- out large cost.

Further features are given in the dependant claims. The invention will, in the following, be described in detail with reference to an example of preferred embodiments.

Examples The invention will be described hereinafter with reference to the accompanying drawings, where Figure 1 shows a cross section of an embodiment of the invention, fastened to a floating collar, which consists of a simple pipe, Figure 2 shows a sketch of the device in Figure 1, from the front, fastened to a floating collar, Figure 3 shows a sketch of another embodiment for cleaning twin pipes, from the side, and Figure 4 shows the detail of an embodiment of a cleaning brush.

Figures 1 to 3 show a floating ring or pipe 11 of plastic, which can be lying singly or in pairs on the sea surface. Such floating rings are normally provided with binding clamps (not shown) that combine the two or more floating rings and/or carry railings and other rising structures at the inner edge of the ring. The cleaning device has a carrier roller 12 which is shaped to correspond with the radius of the pipe 11, so that it can ride upon the pipe, which serves as a U shaped track. The axis 13 of the carrier roller 12 carries a protruding stem 14, for example of quadrangled pipe, having an upper part 14A and a lower part 14B protruding below the floating ring 11. At the lower end 14B a hydraulic engine 15 is fastened, with a horizontally protruding axis 16 which carries a rotating brush 17 with an U shaped profile, reciprocal to the diameter of the pipe 11.

The distance between the carrier roller 12 and the cleaning brush 17, and the co-operation with the pipe 11, appears from Figure 2. It shows how an oblique position of the stem 14 can reduce the distance between the two rotating elements, and thereby create a touch pressure for the cleaning brush 17.

For operation of the hydraulic engine 15, at the upper end 14A of the stem 14, a drive unit is placed with an electric motor 18 and a hydraulic pump 19 with cross-over pipes 20 to the engine 15. The drive unit with couplings switch is encapsulated in a case 21 with rising handles 22.

The main advantages of the cleaning device according to the invention, is it's small size and low weight. This means that it can be positioned in place, and operated by one operator, who can also transport the cleaning device past obstructions along the floating collar. The use of hydraulic power as a driving medium will create little noise.

As shown in Figure 2, the device will, in use, be held angularly. In this way, a certain pressure will be exerted between the cleaning brush and the pipe. The distance between the cleaning brush and the carrier roller can be made adjustable, for example in such a way that the cleaning brush is pressed upwards with a spring loading.

Figure 3 shows a modified embodiment of the invention, for use on a twin pipe 11,11', with distancing pieces 30, carrying clamping rings, distributed along the opposing circum- ferences. The most important difference between the above described embodiment and the modified embodiment, is that a twin brush 17,17'is used with an adapter 31 for brushing the underside of distancing pieces 30, which can be distributed along the circumference.

In order to easily place the cleaning brush 17,17'on the floating collar, the carrier arm 14 may have a joint 32, with an horizontal axis tangential to the floating ring, performing an outer joint-part 14B'of the carrier arm 14. This part 14B'of the joint, can be swung with an hydraulic cylinder 33 which is fixed to the upper part of the carrier arm 14, and operated from the aggregate 18,19.

From the floating collar, a row of railing-poles 34 rise, that carry catches 35 for the seine net, at their upper part.

Figure 4 shows a cleaning brush 17 with helical grooves 36 and tops 37, which together will transport loosened particles broadwise out of the fish rearing unit.

1. Cleaning device to clean marine fouling from tube-shaped subsea structures, in particular floating rings for fish rearing units, comprising a carrier holding one or more motor driven brushes that rotates upon the fouled surfaces, characterized in that it comprises a pair of rollers with an upper carrier roller (12) with a substantially U shaped circumferential track, to rest on the floating ring (11), and an under- lying cleaning brush (17) with reciprocal U shaped tracks, and that is connected to a driving engine (15).

2. Cleaning device according to claim 1, characterized in that the carrier roller (12) and the cleaning brush (17) have parallel axes (13,16).

3. Cleaning device according to claim 2, characterized in that the carrier roller (12) and the cleaning brush (17) are fastened to a common carrier (14) which rises up to at least one prehensile handle (22,23), and is a support to a drive unit (18,19), in particular an electric engine driving a hydraulic pump.

4. Cleaning device according to claim 3, characterized in that the carrier (14) constitutes a lever, that with the weight of the drive unit, pressurizes the carrier roller (12) and the cleaning brush (17) to the floating ring.