WO2007071813A1

WO2007071813A1 - Brush structure

Info

Publication number: WO2007071813A1
Application number: PCT/FI2006/000415
Authority: WO
Inventors: Fred Larsen
Original assignee: Lamor Corporation Ab
Priority date: 2005-12-21
Filing date: 2006-12-20
Publication date: 2007-06-28
Also published as: FI20051310A; FI20051310A0; FI125052B

Abstract

The invention relates to a brush structure for removing impurities, especially oil, from the surface of water. The brush of the brush structure comprises a big number of bristles (2) , whose ends form in the direction of rotation of the brush a substantially continuous brush surface (3) , which is limited by edges (4) in the transverse direction. In addition, the brush structure comprises, at least partly beneath the brush in the vicinity of the brush surface, a jacket (5) preventing exit of impurities from the bristles and directing the impurities forward along with the bristles. According to the invention, a part of the bristles are shorter (1) so that recesses (6) transverse in the direction of motion of the brush are formed in the vicinity of them in the brush surface, the recesses extending at least to the one edge (4) of the brush surface thereby forming water collection cavities together with the jacket (5) , along which cavities the water separated from the bristles is allowed to flow out prior to the removal (7) of impurities from the bristles.

Description

BRUSH STRUCTURE

FIELD OF THE INVENTION

The present invention relates to a brush structure defined in the preamble of claim 1 for removing impurities from the surface of water.

BACKGROUND OF THE INVENTION

The invention is, above all, designed for removing oil and oily products from the surface of water, but it is also applicable to removal of other impurities floating on the surface of water, including liquid, powdery and granular agents. Prior art in the field of the invention represent publications FI71596 and EP1003938, which describe rotating brush mats, as well publication EP468992 showing a drum-like brush. In the publications, the bristles of rotating or revolving brushes gather oil or other impurities from the surface of water; and whilst being stuck in the bristles, in gaps between them, the impurities are lifted to the surface of water. The bristles are then cleaned above the water level in various plough or comb structures known per se .

As a yardstick for the efficiency of the brush structure, the separation capability of water and oil is used; this means that as the brush gathers oil, the proportion of water therein from the total amount of liquid is as small as possible. When collecting thick oils, there usually is not a problem, but the closer the viscosity of the oil to be collected is to that of water, the more there will be water remaining among the bristles along with the oil . Naturally, the problems can be alleviated by reducing the rotational speed of the brushes, in which case, most of the water, which is more fluid, flows from between the bristles before purification. However, this is not a desired solution to the problem because in the prevention of impurities, velocity is an important factor, and one always has to try to re- move oil or similar impurities from the surface of water as fast and efficiently as possible.

OBJECTIVE OF THE INVENTION

It is an objective of the invention to eliminate the disadvantages referred to above.

One specific objective of the invention is to disclose a new kind of brush structure enabling one to keep the water content of the oil that has been col- lected and recovered as low as possible, especially when the viscosity of the impurities to be collected is near to that of water.

SUMMARY OF THE INVENTION

The brush structure of the invention is characterized by what is presented in claim 1.

The brush structure of the invention is designed for removing impurities, especially oil, from the surface of water. The brush of the brush structure comprises a big number of bristles, whose ends form a substantially continuous brush surface in the direction of rotation of the brush, the brush surface being limited by the edges in the transverse direction. In addition, the brush structure comprises, at least partly beneath the brush in the vicinity of the brush surface, a jacket preventing exit of the impurities from the bristles and directing the impurities forward along with the bristles, for example, into a suitable collection vessel, a purification point of brushes, etc. A suitable curved jacket preferably is disposed relatively close to the bristle ends, e.g. 5 to 50mm, depending on the diameter of the brush. According to the invention, a part of the bristles are shorter so that in the vicinity of them in the brush surface, recesses transverse in the direction of motion of the brush are formed, the recesses extending at least to the one edge of the brush surface. In this manner, together with the plate-like jacket - a plate - that is impermeable to impurities, the recesses form water collection cavities, along which cavities the water separated from the bristles is allowed to flow out before removal of the impurities from the bristles. In other words, the brush surface of the brush has areas or recesses possessing both length and width, in the vicinity of which the several adjacent bristles are shorter. In this manner, the recesses form, between the jacket and the brush surface, areas favorable to collection of water and separation of oil, and as these areas, in addition, open out of the edges, they thereby form flow paths, along which the water is al- lowed to flow out of the bristles prior to their purification from oil.

The size, structure and shape of the recesses functioning and used according to the invention can vary greatly, depending on the size of the brushes and brush surfaces, the rotational speed of the brushes, the bristle material, the impurity on the surface of water that is to be collected, as well as on the viscosity and temperature of the impurity. It is substantial that the brush surface of the brush has notches, gaps, recesses or the like formed by the bristles that open up sideward in the direction of motion of the brush, so that the water accumulated in them is allowed to flow out of them prior to the purification of the bristles. One has found that a functional solution is one in which the recesses cover most of the surface area of the brush surface and the longer bristles that extend near to the jacket form narrower strips between the recesses.

The recesses can be unidirectional so that they only open to the one edge of the brush, but pref- erably, the recesses extend through the brush surface from its one end to the other. There are recesses throughout the entire brush surface at uniform or suitably alternating intervals. They can be of uniform width, but more suitably, they widen towards the edges so that they have a bigger flow cross section in the vicinity of the edges of the brush surface than in the middle. In the same manner, they can be of uniform depth or increasing in depth towards the edges .

The front edge and rear edge of the recess can be linear or curved or suitable combinations of these. Preferably, however, the shape of the recess is slanting rearward towards the edges of the brush in the direction of rotation thereof. In that case, the rotational movement of the brush together with the shape of the brush achieves in the recess efficient flow of water towards the edges of the recess.

The brush structure according to the invention is equally well applicable to be used in both cylindrical brushes rotating about one shaft and in belt-like brush structures where the brush surface consists at least of two curved brush surfaces and straight brush surfaces between them.

The brush structure according to the invention has significant advantages compared to prior art. In the invention, the water that has gotten into the brush along with the impurities is given a possibility to be separated and removed from among the impurities. The downward directed bristles and the continuous jacket beneath them form between them flow paths, into which the water with a lower viscosity is separated more efficiently due to both gravity and centrifugal force, while the impurities with a higher viscosity remain stuck in the bristles. In this manner, the invention enables higher rotational speeds of brushes, as well as better and cleaner separation results and a bigger collection capacity due to these. While the invention resembles a conventional scraper conveyor, it functions exactly on the contrary. In a scraper conveyor, the rakes scoop up the mass to be conveyed and convey it ahead. In the invention, the rakes, i.e. longer bristles, absorb oil in the same manner as the shorter ones, but ahead and in the rear of them there are gaps, and being more running, the water quickly flows into these gaps and out of them prior to the purification of the brushes. In this manner, in a conventional scraper conveyor, the gaps between the rakes collect the desired mass, whereas in the invention, the gaps between the "rakes" remove the non-desired portion from the collected mass .

LIST OF FIGURES

In the following section, the invention will be described in detail referring to the accompanying drawings, in which Fig. 1 schematically represents one brush according to the invention as seen from the side;

Fig. 2 illustrates a part of the surface of the brush of Fig. 1;

Fig. 3 illustrates one collection device ac- cording to the invention as seen from the top; and

Fig. 4 illustrates the device of Fig. 3 from the side.

DETAILED DESCRIPTION OP THE INVENTION

Figs. 1 and 2 illustrate one brush according to the invention, the drum-like brush having a big number of radial bristles 2, whose ends form a cylindrical brush surface 3 with edges 4. A part of the bristles and in this embodiment the biggest part i.e. about 75% are shorter 1, so that the brush surface has bristle ends at two different heights in the direction of the radius. In this manner, the brush surface has narrower, higher V-shaped walls and corresponding V- shaped wider recesses 6 between them. The tip of "V" in the middle of the brush points to the direction of rotation of the brush. Arranged outside the edges 4 of the brush are flow paths 8, along which the water from the recesses is allowed to flow downwards i.e. against the direction of rotation of the brush.

The operation of the brush is based on coop- eration with a curved jacket 5 (shown in Fig. 4) disposed partly beneath the brush. The curved plate-like jacket is disposed near the brush surface 3, i.e. at a small distance from the ends of the longer bristles. Thus, the longer bristles push the water and impuri- ties ahead of them along a uniform jacket.

The device as shown in Figs. 3 and 4 includes, at both ends thereof, pontoons 9, supported on which the device floats on the water surface. In the middle there is a collection trough 10, into which the impurities to be collected flow. Placed on both sides i.e. two sides of the collection trough, next to each other, are three brushes of the invention, shown in Figs. 1 and 2. The brushes are disposed at a small distance from each other so that a space for flow paths 8 is left between them. A curved plate i.e. a jacket 5 with a curve of about 90 degrees is disposed on the lower surface of the brushes, extending from the lowest point to the edge of the collection trough 10. Placed above the edge of the collection trough is a discharge device 7 known and used per se in the field; that is to say a comb-like structure through which the bristles of the brush pass so that the oil that has stuck to them is scraped off and deposited into the collection trough.

The apparatus functions as follows. As the apparatus floats in the water, on the surface of which there is oil, the brushes are rotated so that they rotate towards the collection trough 10 and the discharge device 7 from beneath. In that case, the oil and water that have stuck to the bristles travel along with the bristles into an area disposed above the curved jacket 5. As there are recesses 6 i.e. free space between the bristles, owing to its lower viscosity and weaker adherence to the bristles, the water is allowed to flow into these recesses more freely than oil and also due to gravity and centrifugal force. Be- cause these recesses are in a free flow connection with the outside of the jacket via the edges of the brush, the water is allowed to freely flow out from top of the jacket before arriving at the discharge device 7. In this manner, by suitably selecting the ro- tational speed of the brush according to the fluids to be processed, the fluid arriving at the discharge device 7 can be made practically anhydrous. The outflow of water is enhanced by the shape of the recesses of the brush surface, the shape slanting rearward in the direction of rotation of the brush towards its edges.

The invention is not limited merely to the examples of its embodiments referred to above, but many modifications are possible within the scope of the inventive idea defined by the claims.

Claims

1. A brush structure for removing impurities from the surface of water, the brush of the brush structure comprising a big number bristles (2) , whose ends form in the direction of rotation of the brush a substantially continuous brush surface (3) , which is limited by edges (4) in the transverse direction, and the brush structure comprises, at least partly beneath the brush in the vicinity of the brush surface, a jacket (5) preventing exit of impurities from the bristles and directing the impurities forward along with the bristles, c ha r a c t e r i z e d in that a part of the bristles are shorter (1) so that in the vicinity of them in the brush surface, recesses (6) transverse in the direction of motion of the brush are formed, the recesses extending at least to the one edge (4) of the brush surface, thereby forming water collection cavities with the jacket (5) , along which cavities the water which is separated from the bris- ties is allowed to flow out before removal (7) of the impurities from the bristles.

2. The brush structure as defined in claim 1, c ha r a c t e r i z e d in that the recess (6) extends to both edges of the brush surface.

3. The brush structure as defined in claim 1 or 2, c h a r a c t e r i z e d in that the recess (6) is of uniform width through its entire length.

4. The brush structure as defined in claim 1 or 2, c h a r a c t e r i z e d in that the recess is increasing in width towards the edges.

5. The brush structure as defined in any one of claims 1 to 4, c h a r a c t e r i z e d in that the front edge and rear edge of the recess (6) are linear.

6. The brush structure as defined in any one of claims 1 to 4, cha ra c t e r i z e d in that the front edge and rear edge of the recess are curved.

7. The brush structure as defined in any one of claims 1 to 6, c h a r a c t e r i z e d in that the recess (6) has a shape slanting rearward in the direction of rotation of the brush towards the edges (4) .

8. The brush structure as defined in any one of claims 1 to 7, c h a r a c t e r i z e d in that the recess has a standard depth or one increasing towards the edge .

9. The brush structure as defined in any one of claims 1 to 8, c h a r a c t e r i z e d in that the brush surface is a cylindrical surface that rotates about a shaft .

10. The brush structure as defined in any one of claims 1 to 8, c h a r a c t e r i z e d in that the brush surface is a surface of a belt-like brush consisting at least of two curved brush surfaces and straight brush surfaces between them.

11. The brush structure as defined in any one of claims 1 to 10, c ha r a c t e r i z e d in that the impurity to be removed from the surface of water is oil.