FIELD OF THE DISCLOSURE

The present disclosure relates to a method for recovering floating matter, and particularly to a method for collecting floating matter from a surface of water. The present disclosure further concerns an arrangement for collecting floating matter from a surface of water.

BACKGROUND OF THE DISCLOSURE

Document WO 2015/044515 A1 discloses a method for collecting oil from a surface of water. The method comprises the steps of collecting oil from a surface of water to bristles of a rotating brush wheel, scraping oil from the bristles of the rotating brush wheel using a scraper comb, leading scraped oil to a space formed between the scraper comb and a wall, the space having a converging shape, leading oil along the converging space to a gap, leading oil through the gap, and leading oil from the gap to a container.

Document Fl 85528 C discloses an oil collecting appliance arranged in the flow duct for oil-mixed water in an oil pollution control vessel, the appliance comprising a chain strand- shaped collecting element, designed to run around at least two shafts, which element is provided with oil collecting brush elements and arranged so that it slopes downwards and forwards in the direction of flow of the water, and at the upper end of which element means of removal are arranged for taking over the oil collected by the collecting appliance. According to the document, brush elements are arranged on horizontally aligned, long and narrow plate-shaped elements situated at intervals from one another in the direction of rotation of the collecting element, which plate-shaped elements are fixed to strand-shaped chains, belts or similar elements that move around the shafts.

A problem with the known method is that it is not suitable for light oils and other floating matter that has low viscosity. Heavy oil having high viscosity is pushed against the gap by the moving bristles but matter having low viscosity cannot be lead to the gap but it flows back to the water without going through the gap to the container.

BRIEF DESCRIPTION OF THE DISCLOSURE

An object of the present disclosure is to provide a method and an arrangement for implementing the method to overcome the above problems.

The object of the disclosure is achieved by a method and an arrangement which are characterized by what is stated in the independent claims. The preferred embodiments of the disclosure are disclosed in the dependent claims. The disclosure is based on the idea of separating collected floating matter from the bristles by bending and releasing the bristles, causing the floating matter spray away from the bristles.

An advantage of the method and arrangement of the disclosure is that it provides an improved collecting efficiency of matter having a low viscosity.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following the disclosure will be described in greater detail by means of preferred embodiments with reference to the accompanying drawings, in which

Figure 1 is a schematic cross sectional view of an embodiment of the disclosure; and Figure 2 is a schematic cross sectional view of an embodiment of the disclosure.

DETAILED DESCRIPTION OF THE DISCLOSURE

The disclosure relates to a method for collecting floating matter from a surface of water. The method comprises collecting floating matter from a surface of water to bristles 1 1 of a rotating brush wheel 10. The brush wheel 10 is submerged at least partly in the water. According to an embodiment of the disclosure the floating matter is oil, preferably light oil.

Preferably the viscosity of the oil is less than 44 mm ² /s at 50 °C. The floating matter may also be fine solid matter, such as powder or flakes.

The method comprises bending and releasing the bristles 1 1 for separating collected floating matter from the bristles 1 1 . In other words, the bristles 1 1 of the rotating brush wheel 10 are first bent for storing elastic energy in the bristles 1 1 . Then the bristles 1 1 are released from the bent state for a rapid release of the stored elastic energy and for generating kinetic energy to the bristles 1 1 , causing the bristles 1 1 to return to their original shape. During this returning motion, the bristles 1 1 and the floating matter collected to the bristles obtain a speed. During the movement, floating matter is acted upon a centrifugal force, causing floating matter to separate from the bristles 1 1 and move away from the bristles 1 1 . When the bristles 1 1 are returned to their original position, the motion of the bristles 1 1 is suddenly stopped, causing floating matter still attached to the bristles 1 1 to separate from the bristles 1 1 due to momentum and move away from the bristles 1 1 . In practise the floating matter is sprayed away from the bristles 1 1 . Floating matter is separated from the bristles 1 1 without scraping the floating matter off from the bristles 1 1 for example using a comb.

The method comprises leading the separated floating matter to a container 40. In other words, the spraying floating matter 1 1 is caught and lead to a container 40. According to an embodiment of the disclosure the bending and releasing of the bristles 1 1 is performed by a bending and releasing means 20 formed by bar or a strip. Preferably the bending and releasing means 20 is arranged at a distance from a body the brush wheel 10 where the bristles protrude, wherein the distance is smaller than the minimum length of the bristles 1 1 .

Preferably the separating of floating matter from the bristles 1 1 is performed as close to the surface of water as possible. According to an embodiment of the disclosure the separating of floating matter from the bristles 1 1 is performed at a position that is at most 90°, alternatively at most 80°, at most 70°, at most 60°, at most 50°, at most 40°, at most 30°, at most 20° or at most 10°, of rotation of the brush wheel 10 using the point where the bristles 1 1 of the rotating brush wheel 10 leave the surface of water as a starting point. This is to prevent floating matter, which may have only a weak adhesion to the bristles 1 1 , from flowing off from the bristles 1 1 before reaching the bending and releasing means 20 and thus returning to the water. The maximum angle, i.e. the position of the separation, depends on the viscosity of the floating matter. According to an embodiment the position of separating floating matter from the bristles 1 1 is adjusted according to the viscosity of the floating matter or to the wave conditions of the water. During higher waves the position of separating can be adjusted at a higher angle compared to the position that can be used when the waves are low. Here the surface of water should be understood as the average surface of water taking the waves into consideration.

The rotating brush wheel 10 has an axis of rotation 12 and the axis of rotation 12 defines a horizontal plane 13. Separating of floating matter from the bristles 1 1 is performed below the horizontal plane 13. In other words, separating of floating matter from the bristles 1 1 is performed between the horizontal plane 13 and the surface of water. Separating floating matter in this way promotes performing the separation as close to the surface of water as possible. It also prevents positioning the brush wheel 10 too deep into the water which would cause increase in drag caused by the water to the brush wheel 10, resulting in higher energy consumption in rotating the brush wheel 10.

The disclosure relates also to an arrangement for collecting floating matter from a surface of water. For example, the arrangement is attached to a marine vessel. The arrangement comprises a rotatable brush wheel 10 for collecting floating matter from a surface of water on bristles 1 1 of the rotatable brush wheel 10.

The arrangement comprises a bending and releasing means 20 arranged to bend and release the bristles 1 1 when the brush wheel 10 rotates for separating collected floating matter from the bristles 1 1 . According to an embodiment the bending and releasing means 20 comprises a bar or a strip.

The arrangement comprises a leading means 30 arranged to lead the separated floating matter to a container 40. According to an embodiment the leading means 30 comprises a guide plate. The guide plate is arranged at a path of the spraying floating matter so that it leads the separated floating matter to the container 40. Alternatively, the leading means 30 is formed by one of more walls of the container 40.

The rotatable brush wheel 10 has an axis of rotation 12 and the axis of rotation 12 defines a horizontal plane 13 when the arrangement is in an operating position. The bending and releasing means 20 is arranged above the surface of water between the lowest point of the rotatable brush wheel 10 and the horizontal plane 13 when the arrangement is in an operating position. In this case the operating position means that the arrangement is partly submerged in water so that the axis of rotation 12 is above the surface of water.