EP2513382B1

EP2513382B1 - Cutter unit equipped with a pump

Info

Publication number: EP2513382B1
Application number: EP10837095.8A
Authority: EP
Inventors: Toni Mikkola
Original assignee: Lannen Mce Oy
Current assignee: Laennen Mce Oy
Priority date: 2009-12-14
Filing date: 2010-12-14
Publication date: 2019-11-27
Anticipated expiration: 2030-12-14
Also published as: FI125993B; FI20090474A0; WO2011073500A1; RU2567060C2; EP2513382A1; EP2513382A4; RU2012129973A; FI20090474A

Description

Invention relates to a cutter unit equipped with a pump which cutter unit comprises a rotatable cutting device with the help of which underwater soil can be cut, wherein the mass, such as the mass created from the soil and water, and that becomes created during the cutting moves inside the cutter unit and further to the pump with which the said mass being in a fluid form is pumped to a suitable location.
The publication US 637831 discloses a combination with a suction-pipe of a cutting or stirring device comprising a series of blades supported at their inner ends only. The blades curved back toward the suction-pipe and additionally curved away from their direction of rotation, so that their cutting edges are at an angle to the tangent of the circle of rotation, thus forming blades with a double curvature. The publication JPU 360139857 describes a crushing device rotated by a drive source, such as an underwater motor. The device is formed in a spiral shape on the outer periphery of the main spindle. The outer diameter dimension is gradually enlarged from the tip portion to the base portion. Previously rotating cutting heads used in underwater earthwork, such as dredging, are known which cutting heads are moved at the bottom when the cutting heads separate the soil from the bottom. Further pumps that are adjusted by the cutting head are known with which pumps separated mass and water are pumped further to the shore or to a barge along special pipeworks, such as flexible pipeworks. The rotating cutter separates from the bottom mud, stones, parts of plants and while operating at the shore often also items thrown into water. The cutting head has already a structure in itself that sieves bigger objects, such as stones to a certain extend so that too big stones cannot reach the pump. In practise there has been a disadvantage that fibrous parts, such as roots of aquatic plants or thick stems located at the bottom of the water areas do not become crushed with the cutting head, but they move along the mass to the pump maintaining their long structure and stay in front of the blades of the cutter or in the wings of the pump while rotating. Further even though these kinds of roots of the aquatic plants and other stems would make their way to the pump, they deteriorate considerably the pumping result. With the help of the pumps the mass that has been separated from the bottom is moved even over kilometres. Everything that hinders the pumping raises the energy consumption of the pumping and lessens the profit. Especially when a water area that has a plentiful vegetation is being dredged with the help of the cutting head and with a pump attached to it, it has been stated that the crushing of the flora is advantageous for the succeeding of the forwarding of the separated mass carried out by pumping. With the cutter unit according to the invention an unexpected improvement can be achieved in relation to the current, known technique of earth filling by suction in which the soil that has been separated from the bottom by cutting is pumped elsewhere along a pipework. It is characteristic of the cutter unit according to the invention that a cutting/ crushing device is adjusted between the cutting device and the pump which cutting/ crushing device comprises counter blades and a rotating, double-ended knife edge installed at the front side of these seen from the flow direction of the mass which knife edge is installed in an eccentric way in relation to its axis of rotation.
The advantage of the cutter unit according to the invention is the fact that with the help of it especially plant based parts of plants that have become separated from the bottom and are tough and elongated become crushed in a reliable way into small pieces enough so that they move along the mass both through the pump and later in the pipeworks. The cutting/crushing device according to the invention causes pulse like movement due to the installation of an eccentric knife edge and causes cutting effect of two kinds during the cutting/crushing occurring against the counter blades. These impacts ensure the crushing of the tough parts of plants and ensure their progressive motion immediately through the cutting/crushing device. In the invention the knife edge keeps the suction inlet of the pump clean by cutting the plants that are accumulated to it and also sticky mud masses that otherwise would get stuck at the opening of the suction inlet.
In the following the invention is described more detailed by referring to the accompanying drawings in which

Figure 1 shows a cutter unit according to the invention when the main parts are being separated.
Figures 2 a - f show a cutting/crushing device when the knife edge has various positions seen from the flow direction of the mass.

In the figure 1 parts of a cutter unit are shown in which case a rotatable cutting device 1 functions as the part that processes the soil which cutter unit comprises a hemispherical, processing part that has tip blades 5 and curved side blades 7. The soil and water that have been separated from the gaps between the blades 5 and 7 have a free access inside the cutting device 1. With the help of the suction effect of the pump 4 that comes further on in the unit the soil and water are still sucked inside the cutting device 1.
The soil and water that have penetrated the cutting device 1 come to the cutting/crushing device which comprises in this case a sector part that has approximately a size of a half-circle which sector part is equipped with three counter blades 8. The counter blades 8 are elongated and they are installed in the direction of the radius in relation to the axis 6. The axis 6 is an axis that conveys the rotation to the cutting device 1 and it extends to the tip of the cutting device 1 till the blades 5 and is attached to the body of the blades 5 in order to convey the rotation to the whole cutting device 1.
To the front side of the counter blades 8 a knife edge 2 is adjusted to be rotating along the cutting device 1 which knife edge rotates well near the counter blades 8. The knife edge 2 is double-ended and its at least curved parts have been sharpened. Regarding its body, the knife edge 2 is adjusted to be eccentric in relation to its own rotational centre. The rotational centre is the same as the centre of the axis 6. The body of the knife edge 2 is next to the axis 6 and bypasses the axis 6. The knife edge 2 is attached to the frame 12 of the cutter unit 1 at its ends which frame correspondingly has the counter parts of the attachment in an asymmetrical way. The pump 4 is rotated with the help of a hydraulic motor which motor can be located inside a pump casing. The wings 11 of the pump are shown, also the pole 10 of the axis of the pump 4. The milling fixture has its own motor for example inside a casing 3 from which a power transmission axis 6 is led to the cutting device 1.
In the figure 2a the location of the knife edge 2 is shown in one rotation position. The knife edge 2 has tip parts 9 that are at front in relation to the direction of rotation of the blade. Curved, sharpened parts start from the tips 9 which parts cut or crush parts of plants latest then when they end up between the counter blade 8 and the curved, sharpened part of the knife edge 2. The mass continues to move further to the pump 4 from the gaps between the counter blades 8 and the body 13 of the crushing device.
Figure 2b shows the half-circle structure of the cutting/crushing device in which half-circle structure the part 14 is closed and that part does not have counter blades, either. The knife edge 2 functions efficiently when there are counter blades 8 only at a certain sector and especially in front of the gap that leads to the pump 4.
Figure 2c shows the position of the knife edge 2 in which position an elongated object, like a stem of a plant 15 has penetrated the gap between the counter blades. The curved, sharpened part of the knife edge 2 meets the stem of the plant 15 and if the stem does not become cut straight away, it moves towards the counter blade 8 and being pushed by the curved, sharpened part it moves even towards the rotational centre, like the figure 2d shows. When the stem 15 of the plant moves at the sharpened part, its clipping becomes ensured and its movement towards the centre means still that the knife edge 2 has a greater cutting force when the cutting point will have a smaller radius.
In the figures 2e and 2f there is the second end of the knife edge in which end there is a sharpened part equipped with a steeper curvature at the location of the counter blades 8. The cutting effect of this sharpened part is different compared to the first end. The cutting point against the counter blades 8 is at a larger radius. This kind of cyclical variation of the cutting points intensifies the cutting/crushing and ensures the fact that even the tough parts of plants to be cut can quickly penetrate between the counter blades 8 and can continue to the pump 4.
In the figure 2f the location of the knife edge 2 is shown in its entirety in such a eccentric way that the angle α is approximately 180° or even over it. The collisions of the curved, sharpened parts of the knife edge 2 to the counter blades 8 do not occur at regular intervals, but there is a longer and shorter collision interval by turns. This feature has clearly an improving effect regarding the drift of the tough parts of plants that otherwise are hard to handle. Naturally the drift of the parts of plants can be improved by also a another very strong stream consisting of a fluid mass to be pumped through counter blades 8 to the pump 4.
The sector part comprising counter blades 8 is advantageously under 360°, but most suitably approximately a half-circle. The knife edge 2 is located in such a way (figure 2f) that the sector angle α that it covers is most advantageously 180° or over it, for example angle value α 200°.

Claims

Cutter unit equipped with a pump (4) which cutter unit comprises a rotatable cutting device (1) with the help of which underwater soil can be cut wherein the mass that becomes created during the cutting, such as the mass that becomes created from the soil and water moves inside the cutting device (1) and further to the pump (4) with the help of which pump the mentioned mass is pumped to a suitable location, a cutting/crushing device (2, 8) arranged between the cutting device (1) and the pump (4) which cutting/crushing device comprises counter blades (8) and a rotating knife comprising a continuous knife edge (2) having two ends installed at the front side of said counter blades (8) in the flow direction of the mass which knife edge is installed in an eccentric way in relation to its axis of rotation, characterized in that the knife edge (2) further comprises tips (9), wherein cutting ends of the knife edge (2) are curved in such a way that the tips (9) of the knife edge (2) move ahead in relation to the rest of the knife edge (2) body when the knife edge (2) is rotating.
Cutter unit according to the claim 1, characterized in that elongated counter blades (8) that are installed fixed are located in the direction of the radius.
Cutter unit according to the claim 1, characterized in that the knife edge (2) further comprises a first and second tip (9), wherein the first tip (9) portion of the knife edge (2) has a milder curvature than the second, curved tip (9) portion of the knife edge (2) when the knife edge (2) is rotating.
Cutter unit according to the claim 3, characterized in that the direction of the curvature at least of the second tip (9) part of the knife edge (2) in relation to the direction of the counter blade (8) is such that the curvature of the blade aims to move the piece (15) to be cut/crushed towards the rotational centre of the cutter unit.
Cutter unit according to the claim 1, characterized in that the cutter unit further comprises a sector part having a sector angle equipped with the counter blades (8), wherein the sector angle to which counter blades (8) are located is under 360°.
Cutter unit according to the claim 5, characterized in that the sector angle to which the counter blades (8) are located is under 200°.
Cutter unit according to the claim 5, characterized in that the counter blades (8) are installed to that sector angle through which the mass moves to the pump (4).